Experimental studies of load vibrations when moving the DEC-251 loading crane

Measurement of the parameters of vibrations of the load moved by a self-propelled crane with a flexible rope suspension when the crane moves along an unprepared construction site with irregularities is an urgent task, since it will allow using the obtained numerical values of the vibration parameters to improve the accuracy of the crane’s operation in terms of moving loads. Based on the solution of this problem, it is possible to create systems for automatic damping of cargo vibrations. This will reduce the time spent on performing a work step when moving a load. This also solves the problem of reducing the dynamic loads on the elements of the crane. The article discusses one of the methods for determining the angles of deviations of the point of the load and the point of suspension of the load on the boom when moving the DEK-251 mobile crane along the unevenness of the construction site using the projection-polynomial mathematical model of the optoelectronic system. As an example, the article presents a number of graphs of time dependences of changes in the values of the angles of deviations of the load and the point of suspension of the load when moving over the unevenness of the site of a crane with a boom length of 22 meters and an angle of inclination of the boom of 48 degrees. The cargo was at a height of 4.8 meters, the weight of the cargo was 200 kilograms. The graphical time dependences of the load fluctuations and the load suspension point in the longitudinal plane are given in the form of angles of deviations from the lens center, taking into account the microrelief. The data allows you to calculate the linear coordinates of objects in space. Moreover, the results were obtained taking into account the camera errors.

CALCULATION OF POLYNOMIAL RATIO APPROXIMATED SURFACES OF BIFOCAL LENS

General imperfection of existent synthesis methods of bifocal lens surface is use complexity emerging over lack of analytical solution. Method of successive approximations is relatively simple, its main problem is determination of power polynomial coefficient approximating illuminated and shadow surface of being synthesized lens. To solve this problem it is suggest analytical determination method of polynomial coefficient approximating illuminated and shadow surface of bifocal lens. This method based on equality condition of electric path length of edge beam and beam passing through lens center. It is obtained analytical equation which permit to determine interdependence polynomials coefficients approximating illuminated and shadow surface of bifocal lens. Moreover, been finded equation allow to calculate bifocal lens thickness, that impossible using known methods of synthesis methods of bifocal lens surface. Cross-section of bifocal lens was be calculated with being suggested analytical method.

Hydrography, Circulation, and Mixing at the Calypso Deep (the Deepest Mediterranean Trough) during 2006–09

The mass and flow fields from June 2006 to May 2009 in the Calypso Deep (bottom depth ~5.2 km) are investigated using eddy-resolving surface-to-bottom hydrography (station grid spacing ~0.2°) and two tall moorings yielding current-meter records at depths from 700 m to near bottom. A salty warm lens (excess core salinity and temperature are ~0.01 and 0.025°C relative to the surrounding water) of Cretan Deep Water with a core at ~3000 m and a horizontal (vertical) scale of ~50 km (1.5 km) is identified in June 2006 to be locked over the trough. The lens coincides with local maxima in dissolved oxygen. In October 2006 the salinity content of the lens and of all deeper layers is increased; the oxygen maxima are shifted to the bottom layers, indicating an episodic intrusion of higher-density ventilated Adriatic water. The circulation changes from anticyclonic at all depths in June 2006 to cyclonic below ~2.5 km in October 2006, whereas after January 2007 it is cyclonic at all instrumented depths. The measured currents are weak (mean speeds < 5 cm s−1) and persistent in direction, being mostly along the bottom topography at all current-meter depths. After October 2006, the lens erodes due to salt/heat loss caused predominantly by lateral (intrusive) mixing, which works from the outside toward the lens center. The horizontal diffusivity is on the order of ~10 m2 s−1, near the center of the lens, and ~102 to 103 m2 s−1, at its periphery, with an average error ~15 times the diffusivity value. In the deepest part of the trough and in periods of predominance of vertical mixing the vertical diffusivity at 4400 m is ~(4 ± 3) × 10−3 m2 s−1.

Study of Biomaterials Acoustic Signature Using Annular Lenses

In this work, we study the microstructure of porous alumina Al2O3 through the acoustic signature behavior V(z). This function depends on the low porosity when annular lenses conditions at an operating frequency of 1 GHz are used. In non destructive control, this quantitative investigation which allows the determination of mechanical materials properties is of a great importance in the measurement of the surface waves attenuation in this type of biomaterials. Hence, we have numerically simulated the porous alumina acoustic signatures through variable occultation of generating rays at the lens center, in order to quantify the occultation limiting angle. Consequently, the evaluation of the equivalent Rayleigh velocity using the fast Fourier transform (F.F.T) spectra was achieved thanks to the suppression of the Rayleigh mode generation.

Effects of Grinding Wheel Vibration on Surface Quality of Axisymmetric Aspheric Lens

Minute vibration of grinding wheel greatly restricts machining accuracy of axisymmetric aspheric surface in precision grinding. This paper is dedicated to analysis micro-topography of grinding surface under grinding wheel vibration. The relative motion track of wheel to ideal lens surface and the interference of them are involved to study the effects of grinding wheel vibration on surface quality. For different operation parameters, the processed surface presents various micro-topography, and the restriction extent of vibration to surface quality is also different. Vibration waveform in the region near lens center is smoothed greatly by the interference of wheel and the processed surface. Therefore, surface quality gets some improvement from edge to center for axisymmetric aspheric lens. Experiment results verified the validity of the theoretical analysis.

The optics of the growing lungfish eye: Lens shape, focal ratio and pupillary movements inNeoceratodus forsteri(Krefft, 1870)

Lungfish (order Dipnoi) evolved during the Devonian period and are believed to be the closest living relatives to the land vertebrates. Here we describe the previously unknown morphology of the lungfish eye in order to examine ocular adaptations present in early sarcopterygian fish. Unlike many teleosts, the Australian lungfishNeoceratodus forsteripossesses a mobile pupil with a slow pupillary response similar to amphibians. The structure of the eye changes from juvenile to adult, with both eye and lens becoming more elliptical in shape with growth. This change in structure results in a decrease in focal ratio (the distance from lens center to the retina divided by the lens radius) and increased retinal illumination in adult fish. Despite a degree of lenticular correction for spherical aberration, there is considerable variation across the lens. A re-calculation of spatial resolving power using measured focal ratios from cryosectioning reveals a low ability to discriminate fine detail. The dipnoan eye shares more features with amphibian eyes than with most teleost eyes, which may echo the visual needs of this living fossil.