2,090 research outputs found
A rod-linear cascade model for emulating rotor-stator interaction noise in turbofans: A numerical study
No full textThis manuscript presents a rod-linear cascade model for emulating rotor-stator interaction noise. The model is intended as a test platform for studying noise mitigation techniques for a turbofan fan stage, while it also extends the classical rod-airfoil configuration by considering a row of blades based on realistic geometrical details. The rod-linear cascade model consists of a rod positioned upstream of a 7-blade linear cascade, such that the rod wake impinges onto the central blade. The rod is scaled to obtain a fundamental shedding frequency equal to the first blade passing frequency of the NASA-Glenn Source Diagnostics Test (SDT)fan stage at approach condition. The cascade blade profile is also based on the OGV of the SDT sampled at 90% of the radial span. Subsequently, numerical simulations are performed using lattice-Boltzmann Method on a computational setup comprised of a contraction and a test section enclosing the rod-linear cascade model. The integral length scales of the rod wake and the mean loading of the central blade have been found to be in good agreement with the trends observed in the SDT fan stage. The primary noise sources are localized at the central blade leading edge, although noise propagation to the far-field is influenced by additional diffraction by the other blades. Furthermore, the acoustic-blade row interaction causes intense pressure fluctuation within the inter-blade channels, including in those that are not directly affected by the rod wake.Green Open Access added to TU Delft Institutional Repository ‘You share, we take care!’ – Taverne project https://www.openaccess.nl/en/you-share-we-take-care Otherwise as indicated in the copyright section: the publisher is the copyright holder of this work and the author uses the Dutch legislation to make this work public.Wind Energ
Rod Korns
No full textPhoto showing J. Roderic ("Rod") Korns, a historian of western trails and author of "West from Fort Bridger
Understanding migratory flow caused by helicoid wire spacers in rod bundles: An experimental and theoretical study
No full textThe core of a Liquid Metal Fast Breeder Reactor (LMFBR) consists of cylindrical fuel rods that are wrapped by a helicoidally-wound wire spacer to enhance mixing and to prevent damage by fretting. It is known that the liquid metal close to the rod is forced to follow the wires, and that liquid metal further away from the rod crosses the wires (called: migratory flow). This work aims at gaining more insight into the physics behind migratory flow and to provide a model for its bending angle. To this purpose, the flow field in a 7-rods, wire-wrapped, hexagonal bundle with water is studied within the Reynolds number range of 4990–16330 by using Particle Image Velocimetry (PIV). Refraction of the light is minimized by using Fluorinated Ethylene Propylene (FEP), which is a refractive index-matching (RIM) material. These measurements confirm that liquid near the rod follows the helicoid path and bends cross-wise with respect to the wire further away from the rod. A theoretical model for the bending angle of the flow is derived from the Euler equations and shows that the bending is primarily caused by the pressure gradient field induced by the wire. The model shows a very good correspondence with the experimentally obtained PIV data. These findings improve our understanding of the physics at play in rod bundle flows with wrapped wires and can be of assistance in developing practical correlations for frictional pressure losses and heat transfer in such bundles.Green Open Access added to TU Delft Institutional Repository ‘You share, we take care!’ – Taverne project https://www.openaccess.nl/en/you-share-we-take-care Otherwise as indicated in the copyright section: the publisher is the copyright holder of this work and the author uses the Dutch legislation to make this work public.RST/Reactor Physics and Nuclear MaterialsRST/Radiation, Science and Technolog
Interplanetary robots: true stories of space exploration/ Rod Pyle.
No full textIncludes bibliographical references and index.A NASA insider tells the exciting story of robotic space missions to explore the solar system. Exploring the planets has been a goal of America's space program since the dawn of the space race. This insider's perspective examines incredible missions of robotic spacecraft to every corner of our solar system and beyond. Some were flown into glory, while others were planned and relegated to dusty filing cabinets. All were remarkable in their aspirations. Award-winning science writer Rod Pyle profiles both the remarkable spacecraft and the amazing scientists and engineers who made them possible. From the earliest sprints past Venus and Mars to Voyager1's current explorations of the space between the stars, this exciting book sheds new light on ever-more ambitious journeys designed to increase the human reach into the solar system. Drawing on his perspective as a writer for NASA's Jet Propulsion Laboratory, ground zero for NASA's planetary exploration, the author further details plans now in development to look for signs of life on Jupiter's moon Europa, submarines that will dive into the hazy hydrocarbon lakes of Saturn's moon Titan, and intelligent spacecraft that will operate for months without human intervention on Mars and in the outer solar system well into the 2030s. Equally compelling are programs of exploration that were considered but never left the drawing board, such as automobile-sized biology laboratories designed for a Mars landing in the 1960s and plans to detonate atomic bombs on the moon. Complemented by many rarely-seen photos and illustrations, these stories of incredible engineering achievements, daring imaginations, and technological genius will fascinate and inspire.1 online resourc
Corrective force analysis for scoliosis from implant rod deformation
Full text linkBackground: Scoliosis is a serious disease in which a human spine is abnormally deformed in three dimensions with vertebral rotation. Surgical treatment is attained when the scoliotic spine is corrected into its normal shape by implant rods and screws fixed into the vertebrae. The three-dimensional corrective forces acting at the screws deformed the implant rod during the surgical treatment of scoliosis. The objective of this study was to propose a method to analyze the three-dimensional forces acting at the rod using the changes of implant rod geometry before and after the surgical treatment. Methods: An inverse method based on Finite Element Analysis is proposed. The geometries of implant rod before and after the surgical treatment were measured three dimensionally. The implant rod before the surgical treatment was reconstructed using an elasto-plastic finite element model. The three-dimensional forces were applied iteratively to the rod through the screws such that the rod is deformed the same after the surgical treatment of scoliosis. Findings: The maximum force acting at the screw of each patient ranged from 198 N to 439 N. The magnitude of forces was clinically acceptable. The maximum forces occurred at the lowest fixation level of vertebra of each patient. Interpretation: The three-dimensional forces distribution that deformed the rod can be evaluated using the changes of implant geometry. Although the current clinical cases are still few, this study demonstrated the feasibility of measuring the forces that deformed the implant rod after the surgical treatment of scoliosis
Editorial Board and Author Guidelines
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Development of sealing device wellhead polished rod sucker rod downhole pump
Full text linkРассмотрены проблемы процесса герметизации устьевого полированного штока установки штангового глубинного насоса. Предложена новая конструкция герметизатора полированного штока. Проведены расчеты по основным узлам герметизатора. Показаны положительные результаты испытаний герметизаторов на скважинах НГДУ «Речицанефть». Промысловые испытания разработанного герметизатора показали, что срок эксплуатации одного пакета сальниковых уплотнителей в среднем увеличивается более чем в шесть раз.The author presentsthe problems of sealing process of wellhead polished rod of sucker-rod depth pump instal-
lation. New design of polished rod sealant is proposed. Calculations were made for the main components of the
sealant. The author shows the positive results of tests of sealants at wells of NGDU Rechitsaneft. Field tests of the
developed sealant showed that the life of one pack of gland sealants on average increases by more than six times
Controlling the drawability of carbon steel wire rod
No full textThe author proposed an indicator of the deformation capacity of carbon steel wire rod, which took into account the tendency of the metal to hardening and the general level of plastic properties, and determined technological approaches to the designation of the optimal total reduction before intermediate heat treatment by drawing low carbon wire rod and wire rod for metal cord
Visual Basic 2012 Programmer's Reference
No full textRod Stephens is a VB programming guru and the author of more than two dozen programming books, including Stephens' Visual Basic Programming 24-Hour Trainer. He also writes frequently for such magazines as Visual Basic Developer, Visual Basic Programmer's Journal, and Dr. Dobb's Journal. Rod's VB Helper website (vb-helper.com) provides thousands of pages of tips, tricks, and code examples for VB programmer
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