The combination of the hydraulic impactor and positive displacement motor (PDM) is becoming more popular in drilling engineering. However, negatives PDM on cannot be ignored. To improve performance technique, influence fluid pulsation from was studied first; then, structure optimized to its impact force; finally, field tests were carried out 2 wells shallow formation. results indicate that fluc...

Using an alternative mechanism to dissipation or scattering, bistable structures and mechanical metamaterials have shown promise for mitigating the detrimental effects of impact by reversibly locking energy into strained material. Herein, we extend prior works on absorption via computationally explore dependence kinetic transmission velocity mass impactor, with strain rates exceeding 102 s−1. W...

This paper presents research into the energy balance of stressing conveyor belts by impact processes. Research is described in areas measuring resistance to puncture, process, and effect changes height on tensile forces. Measurements were performed a rubber–textile belt with polyamide carcass. Hammers pyramidal spherical impactors used compare examined conveyor. Values obtained for maximum ener...

Introduction: Collisions between planetesimals at speeds of several kilometers per second were common during the early evolution of our Solar System [e.g. 1,2,3,4]. However, shock heating of planetesimals in such impacts has largely been dismissed as a substantial heat source because of the high impact velocity required to shock-heat significant volumes of non-porous rock [e.g. 5,6]. However, r...

1 The Deep Impact Discovery Mission M. F. A’Hearn , L.A. McFadden, C.M. Lisse, D.D. Wellnitz (U.Md), M.J.S. Belton, (Belton Space Initiatives), A. Delamere (Ball Aerospace and Technologies Corp), K.P. Klaasen (JPL), J.Kissel (MPI), K.J. Meech (U.Hawaii), H.J. Melosh (U. Arizona), P.H. Schultz (Brown U.), J.M. Sunshine (SAIC), J. Veverka (Cornell U.), and D.K. Yeomans (JPL) The Deep Impact missi...

Hygroscopic properties of atmospheric particles were studied in the marine tropospheric boundary layer over the Atlantic and Indian Oceans during two consecutive field studies: the Aerosols99 cruise (Atlantic Ocean) from 15 January to 20 February 1999, and the INDOEX cruise (Indian Ocean Experiment) from 23 February to 30 March 1999. The hygroscopic properties were compared to optical and chemi...

Recent ly the s ingle-impact hypothes is for forming the Moon has gained some favorable attention. We present in this paper a series of three-dimensional numerical s imulat ions of an impact be tween the protoear th and an object about 0.1 o f its mass . For computat ional convenience both objects were a s sumed to be composed of granite. We studied the effects on the ou tcome of the collision ...

In the current test procedure proposed by the European Enhanced Vehicle-safety Committee (EEVC) /WG17 for evaluating leg injuries to pedestrians, a legform impactor with a rigid bony structure is used. The risk of damages to knee ligaments is evaluated with the shearing displacement and the bending angle at the knee joint. A recent study has focused on evaluating biofidelity of the legform. How...