498 research outputs found

    Model representation in the PANCOR wall interference assessment code

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    An investigation into the aircraft model description requirements of a wall interference assessment and correction code known as PANCOR was conducted. The accuracy necessary in specifying various elements of the model description were defined. It was found that the specified lift coefficient is the most important model parameter in the wind tunnel simulation. An accurate specification of the model volume was also found to be important. Also developed was a partially automated technique for generating wing lift distributions that are required as input to PANCOR. An existing three dimensional transonic small disturbance code was modified to provide the necessary information. A group of auxiliary computer programs and procedures was developed to help generate the required input for PANCOR

    Sedimentological and diagenetic study of the Early Middle Miocene Jeribe Limestone Formation in selected wells from Iraq northern oilfields (Ajil; Hamrin; Jadid; Khashab)

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    Five subsurface sections covering the entire length of the Jeribe Limestone Formation (Early Middle Miocene) were studied from four oilfields in northern Iraq. It is hoped to unravel this formation microfacies ; depositional environment; diagenetic attributes and their parental processes; and the relationship between these processes and the observed porosity patterns. The microfacies were found to include mudstone, wackestone, packstone, and grainstone, which have been deposited respectively in open platform, restricted platform, and edge platform which represent the lagoonal environment, while the deposits of the lower parts of the Jeribe formation especially in well Hamrin- 2 reflect a deeper fore slope environment. By using the lithofacies association concepts, the depositional model of the Jeribe Formation was built. From a reservoir point of view, the formation suffered from two groups of diagenetic processes. The first one includes the porosity destructive ones such as cementation; compaction; mechanical degradation; anhydritization; and silicification. The second group include porosity enhancers ones which to include dissolution; and dolomitization

    Wall interference and boundary simulation in a transonic wind tunnel with a discretely slotted test section

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    A computational simulation of a transonic wind tunnel test section with longitudinally slotted walls is developed and described herein. The nonlinear slot model includes dynamic pressure effects and a plenum pressure constraint, and each slot is treated individually. The solution is performed using a finite-difference method that solves an extended transonic small disturbance equation. The walls serve as the outer boundary conditions in the relaxation technique, and an interaction procedure is used at the slotted walls. Measured boundary pressures are not required to establish the wall conditions but are currently used to assess the accuracy of the simulation. This method can also calculate a free-air solution as well as solutions that employ the classical homogeneous wall conditions. The simulation is used to examine two commercial transport aircraft models at a supercritical Mach number for zero-lift and cruise conditions. Good agreement between measured and calculated wall pressures is obtained for the model geometries and flow conditions examined herein. Some localized disagreement is noted, which is attributed to improper simulation of viscous effects in the slots

    Uranium and Plutonium Recovery by Tributylphosphate Solvation and Trioctylamine Ion association Mechanisms

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    In this work a flowsheet has been put for the recovery of uranium and plutonium from 2.5M nitric acid solutions using 17.5% tributyl phosphate (TBP) and 2.5% trioctylamine (TOA) in kerosene diluent . The fission products (resulting from irradiated of uranium samples in nuclear research reactor) were removed from the desired actinides U & Pu .The organic phase TBP/TOA/Kerosene, containing both actinides U&Pu were stripped using 0.1 M HNO3. Trioctylamine (2.5 volume ratio ) in mesitylene , has been used in conditions appropriate for the recovery of Pu . From the experiments done using mixer- settler , the concentration of uranium in the organic phase in such conditions was very low ,not exceeding parts of a million

    Enhancing face recognition at a distance using super resolution

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    The characteristics of surveillance video generally include low-resolution images and blurred images. Decreases in image resolution lead to loss of high frequency facial components, which is expected to adversely affect recognition rates. Super resolution (SR) is a technique used to generate a higher resolution image from a given low-resolution, degraded image. Dictionary based super resolution pre-processing techniques have been developed to overcome the problem of low-resolution images in face recognition. However, super resolution reconstruction process, being ill-posed, and results in visual artifacts that can be visually distracting to humans and/or affect machine feature extraction and face recognition algorithms. In this paper, we investigate the impact of two existing super-resolution methods to reconstruct a high resolution from single/multiple low-resolution images on face recognition. We propose an alternative scheme that is based on dictionaries in high frequency wavelet subbands. The performance of the proposed method will be evaluated on databases of high and low-resolution images captured under different illumination conditions and at different distances. We shall demonstrate that the proposed approach at level 3 DWT decomposition has superior performance in comparison to the other super resolution methods

    Exploring Sheraoh Island at South-Eastern Qatar: First Distributional Records of Some Inland and Offshore Biota with Annotated Checklist

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    Sheraoh island is the most remote among Qatari islands, nearly 73.5 km south-eastern of the mainland of the peninsula. In March 2010, a preliminary general survey of the species was conducted. Observations were made partly by wading and snorkeling in the intertidal zone and partly by surveying the inland habitats. In total the 31 species were recorded, 4 species of halophyte plants: Halopeplis perfoliata, Suaeda vermiculata, Salsola baryosoma and Zygophyllum qatarense, one unexpected terrestrial mammal: the cape hare Lepus capensis, 2 species of visiting birds: Motacilla flava and Anthus campestus and one species of sea bird. Phalacrocorax nigrogularis, one dolphin species: Sousa chinensis. The largest richness was found in the marine habitats, 3 species of sea weeds: Colpomenia sinusa, Padina boergesenii and Sargassum boveanum, 3 species of corals: Anomastraea irregularis, Platygyra lamellina and Porites harrisoni, 2 species of nudibranchs: Chromodoris cazae and Chromodoris sp. (unidentified)., 4 crab species: Hermit crab (unidentified), Etisus laevimanus, Grapsus albolineatus and Lambrus prensor, 4 species of echinoderms: Pentacentral mammillatus, Ophiothela venusta, Diadema setosum and Echinometra mathaei, 5 species of bony fish: Doryrhamphus sp. (larva), Cypserulus oligolepis, Lethrinus nebulosus, Cephalopholis miniatus and Hemiramphus marginatus, one species of sea snakes: Hydrophis sp. The most striking result is to collect an unknown nudibranch species and to report the cape hare which is unexpected inhabitant. All figures of this study are published for the first time in Qatar.Qatar Universit

    Construction of dictionaries to reconstruct high-resolution images for face recognition

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    This paper presents an investigation into the construction of over-complete dictionaries to use in reconstructing a super resolution image from a single input low-resolution image for face recognition at a distance. The ultimate aim is to exploit the recently developed Compressive Sensing (CS) theory to develop scalable face recognition schemes that do not require training. Here we shall demonstrate that dictionaries that satisfy the Restricted Isometry Property (RIP) used for CS can achieve face recognition accuracy levels as good as those achieved by dictionaries that are learned from face image databases using elaborate procedures
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