Extent Of Oscillations Research Articles

Long-Range and High-Precision Fault Measurement Based on Hybrid Integrated Chaotic Laser

We propose a long-range, high-precision optical time domain reflectometry (OTDR) technology based on the hybrid integrated short-external-cavity chaotic semiconductor laser (SCSL) which has the advantages of small volume, simple process, low cost, mass production, stable performance, and high yield. The chaotic signal generated by the hybrid integrated SCSL exhibits a certain extent of oscillations and fluctuates randomly in time series. It can be seen from the auto-correlation curve that the generated chaotic signal has no time-delay signature and the theoretical spatial resolution is 1 cm according to the full width of half maximum. In this letter, not only the measurement of multiple single reflection events but also the measurement of double-reflection events was realized, and the spatial resolutions at different distances were verified. Finally, the spatial resolution and range-independent breakpoints measurement has been realized, and the detection range of 76.54 km and the spatial resolution of 1 cm (7.7 million resolved points) have been experimentally demonstrated.

Stability Analysis of Tower Crane During Rotational Motion and Influence of Wind

This research deals with the stability of tower cranes operating with full load under the influence of wind in order to determine dynamic loading. The case of crane motion is rotation around vertical axes. The method of analysis is the calculation of the stability conditions, getting results through modeling and simulations and experimental measurements. Rotational motion is usually followed by heavy oscillations mainly caused by load swinging, which acts on boom, mast and other parts. When crane works in an open place, it undergoes additional aerodynamic forces caused by wind that have variable intensity and direction. This occurrence can create problems with stability, load drop or crane overturning. Based on wind force, simulations will be applied in order to find the nature of oscillations, form and extent of forces that can cause instability, and to calculate parameters for stability conditions. Analysis will be done using modeling and simulations with computer application SimWise 4d. Results gained will be used to get conclusions about dynamic behavior, extent of oscillations, design of crane stability and safety during work. They will be presented in graphical form.

Post-tetanic changes in background gamma oscillations in interhemisphere interactions.

Experiments conducted on the motor cortex of anesthetized rats were performed to study the effects of high-frequency microstimulation of one of the hemispheres on oscillation parameters in neuronal networks containing callosal cells. Before tetanization, there were three modes in the distribution of gamma oscillation periods, corresponding to frequencies of 40-60, 70-100, and 100-200 Hz. In cells active in pre-tetanization background conditions, the three modes were retained after tetanization; there was a relative increase in the number of oscillatory interactions in that part of the gamma range (40-60 Hz) which dominated before tetanization. The distribution of oscillation periods in neurons which became active in background conditions after tetanization contained the same three modes. Tetanization resulted in a relative decrease in the number of oscillatory interactions and the number of neuron pairs in which additional synchronization occurred, along with a reduction in the extent of oscillations, which is evidence of reduced synchronization. Existing modeling data taken together with the present results led to the suggestion that these post-tetanization changes were based on a modification of the efficiency of excitatory and inhibitory inputs to neurons in both hemispheres.

Pressure Effects in Adsorption Systems

A study of the occurrence of large pressure and flow transients when a strongly adsorbed gas is fed to a column which is initially loaded with a lightly adsorbed gas is presented here. Under certain conditions, these transients can cause premature breakthrough and change the shape of the breakthrough curve. This will result in improper estimation of adsorption parameters by the dynamic column loading method and lower apparent adsorption capacity in a full scale unit. A data acquisition system was used to record the pressure and flow transients. An isothermal PDE model developed to study these transients agreed reasonably well with the nonisothermal experimental results. The PDE model predicts that pressure and flow transients will occur during step and pulse~tests conducted to obtain adsorption and mass transfer parameters by the chromatographic method. For instance, lower adsorption capacity will be realized during step tests due to lowering in column pressure. Oscillations were observed when columns are connected in series. The PDE model also predicts these oscillations. Simulations indicate that the extent of oscillations is dependent on the dead volume between columns.

Detergent Foam Images as Analogue/Digital Model Fluids. 1. Phase Behavior and Effective Pair Potentials

Detergent foam images are investigated as analogue/digital (A/D) models for simple fluids. Results of foam preparation/image processing experiments with quasi-two-dimensional systems are illustrated. In the analysis, the pair and triplet correlation functions, g(r) and ξ(ϑ,s;r), are measured for the vertexes of plateau border networks. The phase morphology is characterized by the amplitude and extent of oscillations in g(r). Effective pair potentials u(r) are calculated via the lowest order equation in the Born−Yvon−Green hierarchy. The u(r) are further investigated via Monte Carlo calculations and the Morse function. The experimental data are used to calculate the pair correlation entropy and the compressibility factor as functions of particle number density. These and other observables enable comparisons between the model systems and real atomic fluids. Overall, the results show foam images to mimic fluid structure at the atomic level in several respects. For the experimental conditions discussed, succe...

Diurnal oscillatory movements of growing leaves of tobacco

The analysis of diurnal oscillatory movements of tobacco leaves was used in the diagnosis of viral infection of plants. The oscillatory helices circumscribed by a growing leaf of a healthy plant were regular, but some deviations, particularly in the transition points, were recorded. In order to make clear the cause of these irregularities of trajectory, the course of elongation of leaf petiole and blade in relation to localization and shift of zones of elongation during ontogenesis was analysed. The present analysis is similar to that described by the author's earlier experiments with pea roots. Oscillatory curves circumscribed by petiole, projected on a horizontal plane, were compared with curves circumscribed by the blade tip. The analysis of the leaves of different ages enabled us to study this process in dependence on growth rate. It was confirmed that oscillations are a result of elongation; the extent of oscillations is quantitatively dependent on the growth rate. An analysis of the zones of growth showed that in petiole the active meristems are localized near to its base while in the leaf lamina they move gradually during the ontogenesis from the apical to the basal part of the leaf blade. Active meristems of young rapidly growing leaves are localized approximately in the middle of the blade while those of old leaves were found in close proximity to the base of the lamina. The growth rate of petiole can be expressed in hundreds of mm per hour (4.8×10−2 mm h−1); half of this value was recorded for its apical part. The growth rate of leaf blade was found approximately ten times higher (3.2×10−1 mm h−1). The oscillatory movements of growing leaf consists of two integrate components: of oscillations originating in the base of the petiole and of oscillations of leaf blade the centrum of which is localized in the basal third of the blade. The arrangement of the experiments did not enable us to determine to what extent the phototropic response of leaf blade participates in leaf movements. The movements of leaves of an intact plant are evidently affected by rhythmic stem oscillations. Stem is an integral part of a system which participates in the transfer of information in plants.