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Effect of randomly distributed polypropylene fiber reinforcement on the shear behavior of sandy soil

, stiffness) as well as their spatial configuration (e.g., matrix packing and fiber orientation, fiber distribution). However,a limited number of studies have been focused on the investigation of the behavior of polypropylene fiber reinforced sand using the direct shear apparatus. This paper presents the experimental results of direct shear tests carried out on sand samples reinforced with polypropylene fibers. Results of this study are presented and discussed regarding the effect of relative density, normal stress and fiber percentage on the shearbehavior of reinforced

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Cantilever Beam Natural Frequencies in Centrifugal Inertia Field

Abstract

In the advanced mechanical science the well known fact is that the gravity influences on the natural frequencies and modes even for the vertical structures and pillars. But, the condition that should be fulfilled in order for the gravity to be taken into account is connected with the ration between the gravity value and the geometrical cross section inertia. The gravity is related to the earth acceleration but for moving structures there exist many other acceleration exaggerated forces and such are forces caused by the centrifugal accelerations. Large rotating structures, as wind power generators, chopper wings, large antennas and radars, unfolding space structures and many others are such examples. It is expected, that acceleration based forces influence on the structure modal and frequency properties, which is a subject of the present investigations.

In the paper, rotating beams are subject to investigations and modal and frequency analysis is carried out. Analytical dependences for the natural resonances are derived and their dependences on the angular velocity and centrifugal accelerations are derived. Several examples of large rotating beams with different orientations of the rotating shaft are presented. Numerical experiments are conducted. Time histories of the beam tip deflections, that depict the beam oscillations are presented.

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Design of Gravity Assist trajectory from Earth to Jupiter

took one G. A. from Jupiter, one from Saturn, later from Uranus, and then move up to Neptune and beyond. Galileo passed by Venus then twice by Earth, and finally go up to its path Jupiter. Cassini passed by Venus twice, then Earth, and finally Jupiter on the way to Saturn [ 1 , 2 , 3 ]. In a gravity assist trajectory, angular momentum is transferred from the orbiting planet to a spacecraft, while the value of it’s speed relative to planet is not changed during a gravity assist flyby, but it’s direction is changed. However, both value and direction of spacecraft

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Numerical modeling of open pit (OP) to underground (UG) transition in coal mining

References [1] AHMED H.M., EBERHARDT E., DUNBAR W.S., Interaction between block caving and rock slope deformation kinematics as a function of cave position and orientation of discontinuities, Institute of Materials, Minerals and Mining and The Aus. IMM, 2014. [2] BAI M., KENDORSKI F., VAN ROOSENDAAL D., Chinese and North American high-extraction underground coal mining strata behavior and water protection experience and guidelines, Proceedings of the 14th International Conference on Ground Control in Mining, Morgantown 1995

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Concrete surface evaluation based on the reflected TLS laser beam’s intensity image classification

captured by TLS based on Ground Control Points (GCPs) (terrain/dam details) were geometrically transformed, so that they received a consistent orientation. Assuming that the measuring of laser beam reflection intensity allows for diagnosis of concrete construction conditions, [ 13 ] performed an analytical experiment exploring possibilities of using automated image recognition methods such as ISODATA (Iterative Self- Organizing Data Analysis Technique), [ 9 ]) used for unsupervised classification of multispectral satellite images [ 5 , 6 ]. This technique allows for

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On the perturbed restricted three-body problem

evaluations regarding the masses and the distances of the participating bodies. In this way, a classic example in space dynamics is the Sun-Earth-Moon system. Some important contributions related to the libration points in the restricted three-body problem with one or both primaries are oblate spheroids when the equatorial plane is coincident with the plane of motion were studied by Subbarao and Sharma [ 28 ], Sharma and Subbarao [ 23 ], and Markellos et al. [ 20 ]. Abouelmagd [ 9 ] also studied the effects of oblateness J 2 and J 4 for the more massive primary in the

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