1,690 research outputs found

    Scoring Dawg Core Breakoff and Retention Mechanism

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    This novel core break-off and retention mechanism consists of a scoring dawg controlled by a set of two tubes (a drill tube and an inner tube). The drill tube and the inner tube have longitudinal concentric holes. The solution can be implemented in an eccentric tube configuration as well where the tubes have eccentric longitudinal holes. The inner tube presents at the bottom two control surfaces for controlling the orientation of the scoring dawg. The drill tube presents a sunk-in profile on the inside of the wall for housing the scoring dawg. The inner tube rotation relative to the drill tube actively controls the orientation of the scoring dawg and hence its penetration and retrieval from the core. The scoring dawg presents a shaft, two axially spaced arms, and a tooth. The two arms slide on the control surfaces of the inner tube. The tooth, when rotated, can penetrate or be extracted from the core. During drilling, the two tubes move together maintaining the scoring dawg completely outside the core. After the desired drilling depth has been reached the inner tube is rotated relative to the drill tube such that the tooth of the scoring dawg moves toward the central axis. By rotating the drill tube, the scoring dawg can score the core and so reduce its cross sectional area. The scoring dawg can also act as a stress concentrator for breaking the core in torsion or tension. After breaking the core, the scoring dawg can act as a core retention mechanism. For scoring, it requires the core to be attached to the rock. If the core is broken, the dawg can be used as a retention mechanism. The scoring dawg requires a hard-tip insert like tungsten carbide for scoring hard rocks. The relative rotation of the two tubes can be controlled manually or by an additional actuator. In the implemented design solution the bit rotation for scoring was in the same direction as the drilling. The device was tested for limestone cores and basalt cores. The torque required for breaking the 10-mm diameter limestone cores was 5 to 5.8 lb-in. (0.56 to 0.66 N-m)

    ORTOFOTOMAPS USE AND SYSTEM GNSS POSITION DETERMINATION ROMPOS PROJECT MANAGEMENT MINE CLOSURE IN MARAMUREŞ COUNTY THE USE OF GIS

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    Is the use ortofotomaps and GNSS position determination system ROMPOS, project management of mine closures, the current concern to policy makers in the county of Maramures. In making decisions on mine closure project management can use GNSS positioning systems positioning and target areas ortofotomaps scale 1:1000, 1:2000 or 1:5000. Good decisions in drafting mine closures has to their conservation and environmental protection, and can be more easily taken knowingly when using ortofotomaps and GNSS positioning systems ROMPOS with Information Systems Geographic, which are indispensable in all fields, and particularly in developing these projects. presented previously are parts of GNSS positioning system ROMPOS, its use in decision making on projects of mine closures and benefits arising from this use in this area. In the final draw general conclusions and specific to look at using GNSS positioning systems ROMPOS ortofotomaps position determination and decision making on projects of mine closures, but the usefulness and speed in making decision systems using these relatively new in Romania, and especially in Maramures count

    System for Packaging Planetary Samples for Return to Earth

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    A system is proposed for packaging material samples on a remote planet (especially Mars) in sealed sample tubes in preparation for later return to Earth. The sample tubes (Figure 1) would comprise (1) tubes initially having open tops and closed bottoms; (2) small, bellows-like collapsible bodies inside the tubes at their bottoms; and (3) plugs to be eventually used to close the tops of the tubes. The top inner surface of each tube would be coated with solder. The side of each plug, which would fit snugly into a tube, would feature a solder-filled ring groove. The system would include equipment for storing, manipulating, filling, and sealing the tubes. The containerization system (see Figure 2) will be organized in stations and will include: the storage station, the loading station, and the heating station. These stations can be structured in circular or linear pattern to minimize the manipulator complexity, allowing for compact design and mass efficiency. The manipulation of the sample tube between stations is done by a simple manipulator arm. The storage station contains the unloaded sample tubes and the plugs before sealing as well as the sealed sample tubes with samples after loading and sealing. The chambers at the storage station also allow for plug insertion into the sample tube. At the loading station the sample is poured or inserted into the sample tube and then the tube is topped off. At the heating station the plug is heated so the solder ring melts and seals the plug to the sample tube. The process is performed as follows: Each tube is filled or slightly overfilled with sample material and the excess sample material is wiped off the top. Then, the plug is inserted into the top section of the tube packing the sample material against the collapsible bellowslike body allowing the accommodation of the sample volume. The plug and the top of the tube are heated momentarily to melt the solder in order to seal the tube

    Radio Propagation Environment Analysis for Neutrino Radio Detection in Salt Mines

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    Abstract a We consider a neutrino large-scale radio Cherenkov observatory in a Romanian salt mine. We include propagation effects on the radio signal generated and make a threshold analysis, taking into account how the pulse couples to a realistic receiver and signal-to-noise ratio limiting situations

    Delayed Capital Injections for a Risk Process with Markovian Arrivals

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    In this paper we propose a generalisation to the Markov Arrival Process (MAP) risk model, by allowing for a delayed receipt of required capital injections whenever the surplus of an insurance firm is negative. Delayed capital injections often appear in practice due to the time taken for administrative and processing purposes of the funds from a third party or the shareholders of a firm. We introduce a MAP risk model that allows for capital injections to be received instantaneously, or with a random delay, depending on the amount of deficit experienced by the firm. For this model, we derive a system of Fredholm integral equations of the second kind for the Gerber-Shiu function and obtain an explicit expression (in matrix form) in terms of the Gerber-Shiu function of the MAP risk model without capital injections. In addition, we show that the expected discounted accumulated capital injections and the expected discounted overall time in red, up to the time of ruin, satisfy a similar integral equation, which can also be solved explicitly. Finally, to illustrate the applicability of our results, numerical examples are given

    Biblade Sampler

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    A BiBlade sampler may include a first blade and a second blade in a retracted position. The BiBlade sampler may also include a gripper, which is driven by an actuator. The gripper may include a plurality of fingers to force the first blade and the second blade to remain in a retracted position. When the fingers are unhooked, the first blade and the second blade penetrate a surface of an object

    739 observed NEAs and new 2-4m survey statistics within the EURONEAR network

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    We report follow-up observations of 477 program Near-Earth Asteroids (NEAs) using nine telescopes of the EURONEAR network having apertures between 0.3 and 4.2 m. Adding these NEAs to our previous results we now count 739 program NEAs followed-up by the EURONEAR network since 2006. The targets were selected using EURONEAR planning tools focusing on high priority objects. Analyzing the resulting orbital improvements suggests astrometric follow-up is most important days to weeks after discovery, with recovery at a new opposition also valuable. Additionally we observed 40 survey fields spanning three nights covering 11 sq. degrees near opposition, using the Wide Field Camera on the 2.5m Isaac Newton Telescope (INT), resulting in 104 discovered main belt asteroids (MBAs) and another 626 unknown one-night objects. These fields, plus program NEA fields from the INT and from the wide field MOSAIC II camera on the Blanco 4m telescope, generated around 12,000 observations of 2,000 minor planets (mostly MBAs) observed in 34 square degrees. We identify Near Earth Object (NEO) candidates among the unknown (single night) objects using three selection criteria. Testing these criteria on the (known) program NEAs shows the best selection methods are our epsilon-miu model which checks solar elongation and sky motion and the MPC's NEO rating tool. Our new data show that on average 0.5 NEO candidates per square degree should be observable in a 2m-class survey (in agreement with past results), while an average of 2.7 NEO candidates per square degree should be observable in a 4m-class survey (although our Blanco statistics were affected by clouds). At opposition just over 100 MBAs (1.6 unknown to every 1 known) per square degree are detectable to R=22 in a 2m survey based on the INT data, while our two best ecliptic Blanco fields away from opposition lead to 135 MBAs (2 unknown to every 1 known) to R=23.Comment: Published in Planetary and Space Sciences (Sep 2013

    COMPARATIVE STUDY ON THE USE OF GNSS TECHNOLOGY AND TOTAL STATIONS IN THE GENERAL CADASTRE WORKS IN ROMANIA

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    It presents the use of GNSS technology and total stations in the general cadastre works in Romania and a comparative study between the two methods of measurement, and their use together. When using total stations and other '' classical '' measurement methods, it is imperative to reduce projection distance before compensating for the measurements and then determining the coordinates. The widespread use in Romania of measurement methods using GNSS technology and the RTK measurement method, especially the latter for detail points, is beneficial because distance reduction is no longer necessary and generally there are no problems as before when distances are measured with total stations if it is not reduced to the projection plan. Finally, conclusions are drawn from the use of GNSS technology and total stations separately and together in cadastral elevations for the general cadastre. Conclusions on the methods of measurement and the study compared to the two methods of measurement are auspicious and should be learned by those working for the implementation of the general cadastre in Romania.
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