Function Of Angular Displacement Research Articles

Multilayer planar inductor array based angular position sensor for cryogenic application

The design, development and testing of a cryogenically operated multilayer planar inductor array based eddy current angular position/rotation transducer is claimed. An array of 4 multi-layered coils is used to divide the 360° into four sectors of 90° each. Switching between each of the inductor is done by a cold electronics based multiplexer circuit coupled to an unbuffered inverter LC oscillator. The angular displacement is a function of frequency of cold electronic LC oscillator. The pickup coil forms the inductor of the oscillator which is operated down to 4.2 K and uses thermal cycled stable components. The change in frequency as a function of angular displacement was calibrated at cryogenic temperatures. The developed sensor was found to have good thermal stability, sensitivity and repeatability over the entire cryogenic range.

Geometrical and mechanical characteristics of deformed balance spring obtained by simulation study

This paper analyzes the geometrical and mechanical characteristics of balance springs, which have the most important influence on the oscillation rate of the balance wheel and, consequently, the most decisive effects on the timekeeper’s accuracy. These characteristics are obtained by a set of SolidWorks simulations of static structural studies based on the finite element model, which are performed and accomplished in a specific and original way. Our study demonstrates that the position of the balance spring center of mass and its momentum of inertia are not constant but depend on the angular displacement of the spring collet end. It also shows that the torque spring rate (the spring stiffness) varies as a function of angular displacement during the balanced spring twist. All results are presented numerically and graphically by a set of diagrams and can contribute to the better understanding of the balance spring geometrical and mechanical features and, therefore, be applied for improving a timepiece’s accuracy. Moreover, the method of simulation study disclosed and explained in this paper provides general suggestions and guidance for similar studies. The accuracy of the presented results, as well as the validity of the complete simulation-based method, is proven by the experimentally determined relationship between balance spring restoring torque, stiffness, and spring angular displacement.

Design and Demonstration of a Test-Rig for Static Performance-Studies of Permanent Magnet Couplings

The design and construction of an easy-to-use test-rig for permanent magnet couplings is presented. Static torque of permanent magnet couplings as a function of angular displacement is measured of permanent magnet couplings through an semi-automated test system. The test-rig is capable of measuring torque up to 240 Nm (in increments of 0.1 Nm) at a angular step of 0.0011 degrees (mechanical). Axial, radial, and angular misalignment can be imposed on the coupling in order to study abnormal and faulty operating conditions. This can also be used to assess installation tolerances. Measured data is stored in a USB thumb-drive, and no additional software or hardware is needed to operate the test-rig. Tests of the aligned static torque performance of two different cylindrical couplings are presented along with radial and axial misalignment-tests of one. The results demonstrates the diversity and usefulness of the the designed test-rig. Furthermore, the coupling-performance shows a clear influence of end-effects for axially short couplings, and are found to be very robust to small misalignment.

Special Application Magnetorheological Valve Numerical and Experimental Analysis

The paper addresses analytical, numerical and experimental aspects of the design of magnetorheological (MR) fluid valve. Magnetic flux in valve’s cross-section is analysed with the help of finite element method (FEM) software. Based on the magnetic field intensity distribution within valve’s MR fluid annular gap, simulation model of the shock absorber equipped with newly designed MR valves is developed. Prototypes of MR valve are built and embedded in the stationary barrier of the rotary shock absorber, instead of standard, passive check valves. Simulation and preliminary experimental results comprising resistance force values as a function of angular displacement and angular velocity are presented.

Anterolateral and Medial Locking Plate Stiffness in Distal Tibial Fracture Model

The purpose of this study was to compare the axial and torsional stiffness between anterolateral and medial distal tibial locking plates in a pilon fracture model. The biomechanical stiffness of anterolateral or medial plated pilon fracture models was evaluated. Six Sawbones Composite Tibiae with a simulated pilon fracture representing varus or valgus comminution (OTA 43-A2.2) were plated with a Synthes 3.5-mm contoured LCP anterolateral or medial locking distal tibia plate. Load as a function of axial displacement and torque as a function of angular displacement were recorded. Each tibia was tested with a fracture wedge in place and removed with a medial and then anterolateral plate. Loading the tibial plateau medial to the central axis, no significant difference in mean stiffness between the anterolateral and medial plates was demonstrated with the fracture wedge in place. A significant difference was demonstrated with the wedge removed. Loading the plateau posterior to the central axis, no significant difference in mean stiffness between plates was demonstrated with the wedge in place or removed. With the wedge in place, there was a significant difference in mean torsional stiffness for clockwise rotation, but not counterclockwise rotation. With the wedge removed, no significant difference appeared in mean stiffness for clockwise and counterclockwise rotation. Distal tibia extra-articular fractures stabilized with anterolateral or medial locking plate constructs demonstrated no statistically significant difference in biomechanical stiffness in compression and torsion testing. We believe this study indicates the primary concern when treating a pilon fracture may be soft-tissue considerations. Further clinical studies are required before definitive changes can be recommended regarding pilon fracture fixation.

Individual differences in ERPs during mental rotation of characters: Lateralization, and performance level

The cognitive process of imaging an object turning around is called mental rotation. Many studies have been put forward analyzing mental rotation by means of event-related potentials (ERPs). Event-related potentials (ERPs) were measured during mental rotation of characters in a sample ( N = 82) with a sufficient size to obtain even small effects. A bilateral ERP amplitude modulation as a function of angular displacement was observed at parietal leads without any lateralization. Sex had no effect on mental rotation of characters, neither with respect to performance nor with respect to brain potentials. When the sample was split into groups of high- and low-performers, however, the results indicated (a) in line with the idea of neural efficiency substantially larger amplitudes for low-performers; (b) that the smaller amplitudes of the high-performers involved larger parietal networks; and (c) a left-parietal disengagement of neural activity for high-performers but a right-parietal disengagement for low-performers. The latter finding became evident through an analysis of internal consistencies of ERP amplitudes across conditions and performance levels, showing that internal consistencies were reduced at all three leads in the high-performance group for the biggest rotation angle, relative the other conditions and the low-performing group.

The structure of young star clusters

We analyse and compare the clustering of young stars in Chamaeleon I and Taurus. We compute the mean surface-density of companion stars \bar{N} as a function of angular displacement \theta from each star. We then fit \bar{N}(\theta) with two simultaneous power laws. For Chamaeleon I, the exponents of the power laws are 1.97 and 0.28, with the elbow at ~0.011 degrees. For Taurus, we obtain 2.02 and 0.87, with the elbow at ~0.013 deg. For both star clusters the observational data make quite large systematic excursions from the best fitting curve in the binary regime. These excursions may be attributable to evolutionary effects of the types discussed recently by Nakajima et al. and Bate et al. In the clustering regime the data conform to the best fitting curve very well. We also calculate the box-dimensions for the two star clusters. However, the limited dynamic range makes these estimates simply descriptors of the large-scale clustering, and not admissible evidence for fractality. We also propose two algorithms for objectively generating maps of constant stellar surface-density in young star clusters. Such maps are useful for comparison with molecular-line and dust-continuum maps of star-forming clouds, and with the results of numerical simulations. These maps retain information which is suppressed in the evaluation of \bar{N}(\theta). Analyzing such maps can be used to discriminate between fractal structure and single-level clustering, and to determine the degree of central condensation in small-N clusters. Algorithm I uses a universal smoothing length, and therefore has a restricted dynamic range, but it is implicitly normalized. Algorithm II uses a local smoothing length, which gives it much greater dynamic range, but it has to be normalized explicitly.

A new technique for formant extraction by adaptive smoothing of Fourier spectra.

A new technique to automatically track formant frequencies in voiced speech was developed. Continuity constraints were imposed by adaptively smoothing the short-time Fourier representation. At each point in the time-frequency field, the average energy distribution within a linear window was computed as a function of angular displacement. The angle at which the energy density was closest in magnitude to the point under consideration was chosen as the most likely direction of energy correlation. Weighted smoothing was then performed in that direction. This allowed potential candidate peaks to be enhanced if they lay on a formant track but were not robust enough to be picked on their own merit. Continuous and distinct peak tracks were thus generated even in cases where formants were close. Higher level speech knowledge sources were then called upon to assign peak tracks to formant slots. A measure of reliability was also estimated for each assignment. Experiments conducted on sentences from the TIMIT database yielded very encouraging results. Results will be presented. [Work supported by NSF.]

The emission pattern of vocalizations and directionality of the sonar system in the echolocating bat, Pteronotus parnelli

The radiation patterns of the first three harmonics (approx. 30, 60, 90 kHz) of the mustached bat biosonar signal were measured from vocalizations elicited by cortical microstimulation. The primary foci of the acoustic beam patterns were in front of the mouth but somewhat below the horizontal plane. The prominent second and third harmonics showed sharp cutoffs between 20 degrees and 30 degrees lateral to the midline. Sidelobes were found, suggesting the influence of some vocal tract interference. When compared with previously measured estimates of the directionality of the auditory system, the vocal emission patterns are roughly complementary: Regions of maximum auditory sensitivity are found in areas of submaximal power for the sonar pulse beam pattern. The result is that, for the two most important harmonics, the "biosonar system" (i.e., vocal beam pattern plus receiver directionality) has a broader and more uniform directionality than either component alone. Therefore, within a limited region of space, echo amplitude will vary less as a function of angular displacement. This reduces the confounding influences of absolute sound pressure level on interaural intensity differences.

Determination of Preferred Orientation in Crystals from Surface Diffraction Techniques

This paper will examine a method of determining preferred orientation in reflection diffraction specimen without the use of a camera constant for the electron microscope. This method was devised in the absence of being able to find any such method in the literature. The method was used to study the orientation of nickel crystals grown on the faces of Al2O3 substrates. The diffraction work was done with 75kv (.0446A) electrons on a model HU-11 Hitachi Electron Microscope. Diffraction patterns were recorded on a photographic film in such a manner that successive frames showed pattern change as a function of angular displacement (tilt rotation).If for any surface diffraction pattern, the orientation data of the crystals involved were desired, the following procedure would yield accurate results. The first action is to reproduce the pattern at a convenient size. This can be done by photographic means or by any other means available. Next, the interplanor spacings should be measured for at least three sets of planes which appear in the pattern.

Eye-movement latency, duration, and response time as a function of angular displacement.

Eye-movement latency, duration, and response time as a function of angular displacement.

Design of Automatic Recording Instruments for Magnetic Measurements in a Hot Cell

Two remotely controlled, automatic recording instruments have been designed and constructed for making magnetic measurements in a hot cell: A torque magnetometer for crystal anistropy measurements and a magnetostrictometer for magnetostriction measurements. The magnetometer automatically plots the torque exerted on a slowly rotating sample as a function of angular displacement with respect to the direction of the applied field. Its sensitivity is 2×103 erg/mv. The magnetostrictometer automatically plots strain as a function of applied field. Its maximum sensitivity is 0.2×10−6 in./in. mv. Emphasis is placed on design features that enable these instruments to be operated by remote control. In this type of hot cell work, the handling of the samples to be tested requires the use of an expert operator at the manipulator. For this reason tools and jigs are described that compensate for operator inexperience. Such tools are an automatic screw driver, a vacuum pickup, jigs for bonding prewound strain gauges to the samples, etc.