Circular Displacements Research Articles

Method for Noise Reduction by Averaging the Filtering Results on Circular Displacements Using Wavelet Transform and Local Binary Pattern

Algorithms for noise reduction that use the translation invariant wavelet transform indirectly are spatially selective filtering algorithms in the wavelet domain. These algorithms use the undecimated wavelet transform to accurately determine the coefficients corresponding to the contours in the images, these being processed differently from the other wavelet coefficients. The use of the undecimated wavelet transform in image noise reduction applications leads not only to an improvement in terms of Mean Square Error (MSE), but also in terms of the content quality of the processed images. In the case of noise reduction procedures by truncation of wavelet coefficients, artifacts appear, especially in the approximation of singularities, due to some pseudo-Gibbs phenomena. These artifacts, which appear locally, are troublesome in the case of object recognition applications from images acquired in conditions of nonuniform illumination and low contrast. In this work we propose a method of feature extractor based on undecimated wavelet transform (UWT) and local binary pattern (LBP). The results obtained on images acquired from drones in adverse conditions show promising results in terms of accuracy. The authors show that the displacement-invariant wavelet transform is an very good method of compression and noise reduction in signals.

Design and optimisation of rotary vibrating screening process in silicon photovoltaic panel recycling: A particle-scale model study

The efficient separation of crushed solar panel particles is a critical step in photovoltaics (PV) recycling. In this paper, a DEM-based computer model is used to investigate the separation of crushed solar panel particles in a variety of shapes (including rod-like glass particles and chip-like solar cell particles and small broken residue) at the particle scale in a lab-scale rotary vibrating screen. The screening process of individual particles, including looseness, stratification, collision and penetration, can be well captured by the DEM simulations. Then the effects of several key vibration parameters on screening efficiency are studied, including circular displacements and oscillatory amplitude and frequency, and their underlying mechanism is explored at the particle scale. The simulation results show that with the increase of circular displacements from 1 to 3 mm, the screening efficiency increases from 89.5% to 91.8%. With the rise of oscillatory amplitude from 0.1° to 0.6°, the screening efficiency decreases significantly from 92.0% to 87.3%. With the increase of oscillatory frequency from 10 Hz to 25 Hz, the screening efficiency decreases slightly from 92.1% to 91.2%. The optimal screening condition is identified, i.e., >3 mm circular displacement, <0.1° oscillatory amplitude, and < 10 Hz oscillatory frequency, significantly enhancing screening efficiency. This study is helpful for rotary vibrating screen device scale-up and process optimisation in the PV recycling industry.

SPECTRUM CHARACTERISTICS IN TELEVISION SYSTEMS OBJECTS WITH QUASI-PERIODIC PHASE-TIME CONVERSIONS OF VIDEO INFORMATION

Quasiperiodic phase-time transformations of video information can be car-ried out both due to the objects corresponding displacements themselves, and through the necessary displacements organization, for example, in the signal sensor of television systems. The essence of this transformation type is rel-ative, time-periodic displacements of controlled objects in raster space on the photosensitive surface of the signal sensor, accompanied by changes in the position of the object relative to the optical axis. In this case, large-scale changes in coordinates also affect the angle of each element of the object image. Consequently, the action of the operator of “periodic circular dis-placements” is associated with the occurrence of the effect of relative sup-pression of the upper spatial frequencies of the initial influence. The article shows that in terms of the effect on the spatio-temporal spectrum of the initial impact, it is advisable to classify the operator of “periodic linear displace-ments” as operators of the differential type, and the operator of “periodic circular displacements” as operators of the integral type. Any operator of integral type can be reduced to differential type and vice versa. An example is considered where the operator of periodic circular displacements is easily converted to a differential type when introducing a return circular displace-ment along the same trajectory.

Stress-strain state of the storage silos under the action of the asymmetric load

This paper deals with the investigation of work of the vertical steel cylindrical storage silos for grain with the different thickness of casing sheets and stiffeners at different height sunder the asymmetric wind load. Construction is designed using the analytical method involving decomposition of load into the completed trigonometric series and adding separate stress-strain states of k influence. The construction design model is a thin-walled cylindrical shell reinforced with vertical stiffeners. According to the shell theory, all unknown elements of the stress-strain states from the wind load components are expressed by unknown function ξk (x). In the analysis, the introduced hypotheses were used, which provides for using exponential dependence to describe the thickness changing law of the casing sheets and stiffeners and the equality of the change rate of these characteristics. The obtained results for silos with corrugated wall showed that the desired function which characterizes the stress-strain state of the construction is determined by ratio of the total cross-section area of all stiffeners to the cross-sectional area of the silo provided this ratio is constant at all heights. Represented calculation formulas for radial, circular and longitudinal displacements, and for strains in cross-sections are simple enough for using in the engineering practice.

Exploring wear at the nanoscale with circular mode atomic force microscopy.

The development of atomic force microscopy (AFM) has allowed wear mechanisms to be investigated at the nanometer scale by means of a single asperity contact generated by an AFM tip and an interacting surface. However, the low wear rate at the nanoscale and the thermal drift require fastidious quantitative measurements of the wear volume for determining wear laws. In this paper, we describe a new, effective, experimental methodology based on circular mode AFM, which generates high frequency, circular displacements of the contact. Under such conditions, the wear rate is significant and the drift of the piezoelectric actuator is limited. As a result, well-defined wear tracks are generated and an accurate computation of the wear volume is possible. Finally, we describe the advantages of this method and we report a relevant application example addressing a Cu/Al2O3 nanocomposite material used in industrial applications.

Dynamic response of circular and annular circular plates using spectral element method

This paper presents development of the spectral element method (SEM) for analysis of circular and annular circular plates vibration under impact load. A novel formulation is proposed in frequency domain for conducting spectral element matrix. Several numerical examples are presented in order to demonstrate performance of the presented method compared to other numerical methods in literature. The presented formulation was applied in order to analyze vibration of annular circular plates with various thicknesses and various internal-to-external radius ratios. In addition, annular circular plate displacements subjected to an impact load were calculated using the presented SEM.

Utilization of optical tracking to validate a software-driven isocentric approach to robotic couch movements for proton radiotherapy.

An optical tracking and positioning system (OTPS) was developed to validate the software-driven isocentric (SDI) approach to control the six-degrees-of-freedom movement of a robotic couch. The SDI approach to movements rotating around a predefined isocenter, referred to as a GeoIso, instead of a mechanical pivot point was developed by the robot automation industry. With robotic couch-sag corrections for weight load in a traditional SDI approach, movements could be accurately executed for a GeoIso located within a 500 mm cubic volume on the couch for treatments. The accuracy of SDI movement was investigated using the OTPS. The GeoIso was assumed to align with the proton beam isocenter (RadIso) for gantry at the reference angle. However, the misalignment between GeoIso and RadIso was quantitatively investigated by measuring the displacements at various couch angles for a target placed at the RadIso at an initial couch angle. When circular target displacements occur on a plane, a relative isocenter shift (RIS) correction could be applied in the SDI movement to minimize target displacements. Target displacements at a fixed gantry angle without and with RIS correction were measured for 12 robotic couches. Target displacements for various gantry angles were performed on three couches in gantry rooms to study the gantry-induced RadIso shift. The RIS correction can also be applied for the RadIso shift. A new SDI approach incorporating the RIS correction with the couch sag is described in this study. In parallel, the accuracy of SDI translation movements for various weight loads of patients on the couch was investigated during positioning of patients for proton prostate treatments. For a fixed gantry angle, measured target displacements without RIS correction for couch rotations in the horizontal plane varied from 4 to 20 mm. However, measured displacements perpendicular to couch rotation plane were about 2 mm for all couches. Extracted misalignments of GeoIso and RadIso in the horizontal plane were about 10 mm for one couch and within 3 mm for the rest of couches. After applying the RIS correction, the residual target displacements for couch rotations were within 0.5 mm to RadIso for all couches. For various gantry angles, measured target location for each angle was within 0.5 mm to its excepted location by the preset RadIso shift. Measured target displacements for ± 30° of couch rotations were within 0.5 mm for gantry angles at 0° and 180°. Overall, nearly 85% of couch movements were within 0.5 mm in the horizontal plane and 0.7 mm vector distance from required displacements. The authors present an optical tracking methodology to quantify for software-driven isocentric movements of robotic couches. By applying proper RIS correction for misaligned GeoIso and RadIso for each couch, and the RadIso shifts for a moving gantry, residual target displacements for isocentric couch movements around the actual RadIso can be reduced to submillimeter tolerance.

SU‐C‐103‐01: An Optical Tracking and Positioning System for Proton Therapy

Purpose: An optical tracking and positioning system (OTPS) for proton therapy was developed to study the characteristics of robotic couch movement and the trend of inter‐fractional displacements on positioning patients treated for prostate or brain cancers. Methods: For patient localization, required movements of couch must be precisely executed. Commercial robotic couch with software‐driven six‐degree isocentric freedom was utilized in our clinic. To align couch rotating center within 1 mm to proton beam, movements of couch without or with patient loads were accurately measured within 0.5 mm without and by the OTPS; including a stereoscopically infrared camera and rigid body tools. To investigate large 10 mm inter‐fractional couch displacements with 5.0 mm standard deviation (S.D.) observed on one patient using head mask for immobilization, a mathematic formula, referred to as 3PtTrack method, was developed for studying the trend of inter‐fractional patient movements within head mask. Results: Typical 4.0 mm circular couch displacements were measured at horizontal plane while displacements were 2.0 mm at vertical plane; however, large 20 mm circular displacements were observed at Procure first clinic couch. After applying software‐driven ISO alignment, residual displacements at couch rotation were 0.3 mm. 85% of movements with patient loads on couch were within 0.5 mm to required values at horizontal plane. The 3PtTrack method could place daily QA device to required location within 0.5mm over a period of 3 months. Movements within mask were found to be similar (both less 5.0 mm with 2.0 mm S.D.) for two patients with largely different couch displacements. Conclusion: The couch rotation was well aligned to proton beam by using OTPS. Movements with patient loads were accurately executed. Large couch displacements presented an issue of fixation on head mask to couch, while smaller movement measured by 3PtTrack indicate that patients still moved with masks.

Interface circular inclusion under mixed conditions of interaction with a piecewise homogeneous transversally isotropic space

We reduce the problem of a circular absolutely rigid inclusion of arbitrary shape that is under conditions of complete adhesion to one transversally isotropic half-space and under conditions of smooth contact with another transversally isotropic half-space to a system of two-dimensional singular integral equations. We obtain solutions of this system in an explicit form, which enables us to determine the stress field and the field of displacements in the vicinity of the inclusion under arbitrary load. Dependences of translational and circular displacements of the inclusion on the resultant loads, principal moments, and elastic properties of the half-spaces are determined. We investigate the asymptotics of stresses in the vicinity of the inclusion and determine the directions of the largest and smallest stress concentration.

Wedging of an elastic wedge by a rigid plate under conditions of contact with detaching

We consider a problem of wedging of an elastic wedge by a rigid plate along an edge crack that is located on the axis of symmetry of the wedge and reaches its vertex. The detachment of the crack faces from the surfaces of the plate is taken into account. Using the Wiener–Hopf method, we obtain an analytic solution of the problem. The size of the detachment zone, the stress intensity factor, the distribution of stresses on the line of continuation of the crack and in the contact domain, and circular displacements of the crack faces are determined.

Wedging of an edge crack in the elastic wedge

We study the problem of wedging of an elastic wedge realized along the edge crack with the help of a hard wedge. The analytic solution of the problem is obtained by the Wiener-Hopf method. We determine the stress intensity factors, the distributions of stresses on the continuation of the crack and in the contact zone, and the circular displacements of the crack lips.

Prediction of fatigue lifetime under multiaxial cyclic loading using finite element analysis

Life prediction for GH4169 superalloy thin tubular and notched specimens were investigated under proportional and nonproportional loading with elastic–plastic finite element analysis (FEA). A strain-controlled tension–torsion loading was carried out by applying the axial and circular displacements on one end of the specimen in the cylindrical coordinate system. Uniaxial cyclic stress–strain data at high temperature were used to describe the multi-linear kinematic hardening of the material. The comparison between FEA and experimental results for thin tubular specimen showed that the built model of FE is reliable. A fatigue damage parameter was proposed to predict the fatigue crack initiation life for notched specimen. The results showed that a good agreement was achieved with experimental data.

Radiation problem of normal stress loading of bore surface

AbstractThe radiation of elastic waves at normal harmonic stress loading of a ring strip of the cylindrical bore‐surface in the infinite elastic medium is considered. The wave field is represented by contour integrals. By using the saddle‐point method stress and displacement of asymptotic expansions in the far field were obtained. It is shown that in the far field P‐waves bring radial displacements and stresses, and perpendicular to these, displacements and stresses are caused by S‐waves. In the paper orientation diagrams of radial and circular displacements and frequency dependencies of relative distribution of radiation power source on types of waves are presented. (© 2008 WILEY‐VCH Verlag GmbH &amp; Co. KGaA, Weinheim)

Effect of elastomer slight compressibility

Abstract This paper is concerned with the constitutive equation for slightly compressible elastic material under finite deformations. We show that material slight compressibility can be effectively taken into account in the case of high hydrostatic pressure or highly confined material. In all other situations the application of the incompressible and nearly incompressible material theories gives practically the same results. Therefore it is of interest to consider the problem in which allowing for material slight compressibility leads to results essentially different from those obtained with help of the incompressible material model. In the present paper this difference has been demonstrated for the problem of high hydrostatic pressure causing an increase of the ‘bulk’ and ‘shear’ material moduli. The behavior of a long hollow cylinder of real material under finite deformations is analyzed. The cylinder is subjected to internal pressure and axial and circular displacements at the outer surface. This problem has been solved analytically using the small parameter method. The solution obtained predicts a decrease of the axial and circular displacements of the outer surface under fixed shear (axial and circular) forces when the internal pressure is applied.

Vibrations of an orthotropic plate with an internal flat circular slot

Vibrations of free and clamped transversely isotropic plates with an internal flat circular slot are studied. According to the physical conditions, the normal stresses become uniform within the circular slot and displacements, and the shearing stresses are zero outside the circular slot. These are mixed boundary value problems which give rise to dual integral equations. Following Noble, the dual integral equations are reduced to Fredholm integral equations. Kernals of the integral equations are evaluated by the contour integration technique. The stress intensity factors are obtained for both cases and corresponding isotropic results are deduced. Numerical analysis is performed in the case of Beryl material. The relationship between the dimensionless frequency and the stress intensity factor is presented. The results thus obtained are discussed.

Basic Patterns of Behavior in Wild Anastrepha striata (Diptera: Tephritidae) Flies under Field-Cage Conditions

We describe the diel patterns of feeding, resting, oviposition, and mating behavior of wild Anastrepha striata Schiner flies. Observations were made in a greenhouse (5 m wide, 6 m long, 4 m tall) in which a total of 91 potted guava, sapodilla, orange, and mango trees had been placed. Overall, we found statistically significant differences in fly activity patterns depending upon the hour of day and sex of fly. Most flies (62.3%) emerged between 0900 and 1200 hours with no significant differences between sexes. Young flies (1–15 d of age) fed preferably on napkin strips soaked in a yeast hydrolysate–sucrose mixture, whereas older flies (>30 d of age) preferred ripe fruit. Bubbling and regurgitation behaviors were common and were correlated with feeding times. Individual flies regurgitated a mean of 23.5 ± 1.5 SE drops and reingested them within 12 ± 3.9 min. Oviposition activity by females (which included ovipositor dragging on the fruit surface) followed a bell-shaped pattern with a peak at 1200–1300 hours. Mean clutch size was 1.5 ± 0.13. A. striata mating behavior is very complex and encompasses short- and long-range interactions between males and females. A larger proportion of males called singly (91.3%), but lek formation was also observed (8.7% of all calling males did so in a lek). The most striking feature of the mating behavior (not previously reported in other Anastrepha species) is the formation of female-male pairs that interact for prolonged periods (mean of 21.3 ± 2.3 min, n = 245). While interacting, flies exhibit elaborate courtship behaviors such as repeated labellum-to-labellum contacts (during which actual male-female substance transfer takes place) and circular displacements in front of the mate. In 78 pairs studied in detail, we observed a mean of 13.3 ± 1.9 mating attempts per pair, with a mean duration of 7.3 ± 0.3 s per attempt. Most mating attempts were unsuccessful (unsuccessful/successful mating attempt ratio, 10:1). Actual copulations had a duration of 29.2 ± 2.3 min ( n = 45). A. striata behavior is discussed in relation to behavior of other Diptera (including Anastrepha ).

Structure and dynamics of M13mp19 circular single‐strand DNA: Effects of ionic strength

Dynamic and static light scattering, CD, and optical melting experiments have been conducted on M13mp19 viral circular single-strand DNA as a function of NaCl concentration. Over the 10,000-fold range in concentration from 100 microM to 1.0 M NaCl, the melting curves and CD spectra indicate an increase in base stacking and stability of stacked regions with increased salt concentration. Analysis of dynamic light scattering measurements of the single-strand DNA solutions as a function of K2 from 1.56 to 20 X 10(10) cm-2 indicates the collected autocorrelation functions are biexponential, thus revealing the presence of two decaying dynamic components. These components are taken to correspond to (1) global translational motions of the molecular center of mass and (2) motions of the internal molecular subunits. From the evaluated relaxation rates of these components, diffusion coefficients D0 and Dplat are determined. The center of mass translational diffusion coefficient D0, varies in a nonmonotonic manner, by 10%, from 3.75 X 10(-8) to 3.39 X 10(-8) cm2/s over the NaCl concentration range from 100 microM to 1.0 M. Likewise, the radius of gyration RG, obtained from static light scattering experiments, varies by 15% from 699 to 830 A over the same NaCl range Dplat, the diffusion coefficient of the internal subunits, displays a different dependence on the NaCl concentration and decreases, by nearly 22% in a titratable fashion, from 12.46 X 10(-8) to 10.26 X 10(-8) cm2/s, when the salt is increased from 100 microM to 1.0 M. A semiquantitative interpretation of these results is provided by analysis of the light scattering data in terms of the circular Rouse-Zimm chain. Rouse-Zimm model parameters are estimated from the experimental results, assuming the circular chains are composed of a fixed number of Gaussian segments, N + 1 = 15. The rms displacement of the internal segments, b, is estimated to be the smallest (442 A) in 100 mM NaCl. Increases of b to 467 A in 100 microM and 524 A in 1.0 M NaCl are observed. Meanwhile, the hypothetical friction factor of the internal subunits, f, progressively increases as the NaCl concentration is raised. It is inferred from the evaluated Rouse-Zimm model parameters that both the static flexibility of the circular chain and diffusive displacements of the internal subunits decrease with increases in NaCl concentration from 100 mM to 1.0 M.(ABSTRACT TRUNCATED AT 400 WORDS)