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Sample records for adi internal gears

  1. Bifurcation phenomena in internal dynamics of gear systems

    Hortel M.

    2007-10-01

    Full Text Available The impact effects in gear mesh represent specific phenomena in the dynamic investigation of highspeed light transmission systems with kinematic couplings. They are caused of greater dynamic than static elastic deformations in meshing gear profiles. In term of internal dynamics they are influenced among others by time heteronomous stiffness functions in gear mesh and resonance tuning of stiffness level. The damping in gear mesh and in gear system is concerned significantly in the amplitude progress, greatness and phase shift of relative motion towards stiffness function alternatively towards its modify form in gear mesh. In consequence of these and another actions rise above resonance characteristics certain singular locations with jump amplitude course.

  2. Bending strength model for internal spur gear teeth

    Savage, Michael; Rubadeux, K. L.; Coe, H. H.

    1995-01-01

    Internal spur gear teeth are normally stronger than pinion teeth of the same pitch and face width since external teeth are smaller at the base. However, ring gears which are narrower have an unequal addendum or are made of a material with a lower strength than that of the meshing pinion may be loaded more critically in bending. In this study, a model for the bending strength of an internal gear tooth as a function of the applied load pressure angle is presented which is based on the inscribed Lewis constant strength parabolic beam. The bending model includes a stress concentration factor and an axial compression term which are extensions of the model for an external gear tooth. The geometry of the Lewis factor determination is presented, the iteration to determine the factor is described, and the bending strength J factor is compared to that of an external gear tooth. This strength model will assist optimal design efforts for unequal addendum gears and gears of mixed materials.

  3. Internal strain measurement of carburized gear by neutron diffraction

    Internal strain and stress distributions of carburized transmission gear was non destructively measured by neutron diffraction in order to understand deformation behavior after carburizing. The material used in this study was chromium-molybdenum steel, SCM 420 H. The carburized case depth was determined by microscope and measuring hardness distribution. The diffractions from Fe-110 and 211 planes were used, and internal strain was obtained from the lattice spacing change. Reference coupon specimens were cut from the same carburized gear, and then lattice spacing was measured as stress-free one. As the results, the carburized case depths of shift fork groove and dog clutches were relatively deeper than that of gear wheel. From measured axial, radial and hoop residual strains near the internal spline, large tensile residual strain parallel to the axial direction was generated in the shift fork groove. Furthermore, tensile residual strains parallel to the axial and hoop directions were also generated in the gear wheel. Residual strains of carburized gear were found to be not uniform, and be balanced by local deformation through the whole gear including the shift fork groove and dog clutches. (author)

  4. To internal dynamics of gear systems with split power flow

    Hortel, Milan; Škuderová, Alena

    1. Brno : Univerzita obrany, 2013 - (Stodola, J.; Šťastný, J.; Vališ, D.; Neumann, V.), s. 245-258 ISBN 978-80-7231-939-8 Institutional support: RVO:61388998 Keywords : planetary gear systems * nonlinear dynamics * parametric vibration * time heteronymous damping * impact effects Subject RIV: JT - Propulsion, Motors ; Fuels

  5. Application of x-ray method for measuring internal stress in the gear teeth surface layer

    This paper presents the methodics of the internal stress measurements concerning cylindrical gear teeth of involute profile. There are the method selected, relation between stress and strain presented and conditions of investigation discussed in the study, including preparation of samples for investigation and conditions of the strain measurement. Exemplifying results of stress measurements for teeth of gears made of 4OH steel are shown. Suitability of the developed investigation method is indicated

  6. On optimization of internal/external spur gears tooth bending strength

    Pedersen, Niels Leergaard

    Gear fatigue strength is primarily controlled by the durability and load capacity, the first is typically related to pitting damage and the second to tooth-breakage. The pitting is due to the tooth contact and the shape of the contacting surfaces, the tooth breakage is controlled by the stress...... level at the tooth root. As with most machine elements the design/geometry is defined in standards (ISO). The present work focuses on changing the tooth root design of both external and internal gears, in order to improve the stress concentration factor. The design changes made are compliant with the...... standard, i.e. the optimized gear design can mesh with a standard gear....

  7. Phase-Oriented Gear Systems

    Vranish, John M.

    2007-01-01

    Phase-oriented gear systems are differential planetary transmissions in which each planet gear has two sets of unequal numbers of teeth indexed at prescribed relative angles (phases). The figure illustrates an application of the phase-oriented gearing concept to a relatively simple speed-reducing differential planetary transmission that includes a sun gear, an idler gear, three identical planet gears, a ground internal ring gear, and an output internal ring gear. Typically, the ground internal ring gear and output internal ring gear have different numbers of teeth, giving rise to a progressive and periodic phase shift between the corresponding pairs of teeth engaged by each successive planet gear. To accommodate this phase shift, it is necessary to introduce a compensating phase shift between the ground-gear-engaging and output-gearengaging sections of each planet gear. This is done by individually orienting each planet gear

  8. Gears and gear drives

    Jelaska, Damir T

    2012-01-01

    Understanding how gears are formed and how they interact or 'mesh' with each other is essential when designing equipment that uses gears or gear trains. The way in which gear teeth are formed and how they mesh is determined by their geometry and kinematics, which is the topic of this book.  Gears and Gear Drives provides the reader with comprehensive coverage of gears and gear drives. Spur, helical, bevel, worm and planetary gears are all covered, with consideration given to their classification, geometry, kinematics, accuracy control, load capacity and manufacturing. Cylindric

  9. Nonlinear Dynamic Analysis of Coupled Gear-Rotor-Bearing System with the Effect of Internal and External Excitations

    ZHOU Shihua; SONG Guiqiu; REN Zhaohui; WEN Bangchun

    2016-01-01

    Extensive studies on nonlinear dynamics of gear systems with internal excitation or external excitation respectively have been carried out. However, the nonlinear characteristics of gear systems under combined internal and external excitations are scarcely investigated. An eight-degree-of-freedom(8-DOF) nonlinear spur gear-rotor-bearing model, which contains backlash, transmission error, eccentricity, gravity and input/output torque, is established, and the coupled lateral-torsional vibration characteristics are studied. Based on the equations of motion, the coupled spur gear-rotor-bearing system(SGRBS) is investigated using the Runge-Kutta numerical method, and the effects of rotational speed, error fluctuation and load fluctuation on the dynamic responses are explored. The results show that a diverse range of nonlinear dynamic characteristics such as periodic motion, quasi-periodic motion, chaotic behaviors and impacts exhibited in the system are strongly attributed to the interaction between internal and external excitations. Significantly, the changing rotational speed could effectively control the vibration of the system. Vibration level increases with the increasing error fluctuation. Whereas the load fluctuation has an influence on the nonlinear dynamic characteristics and the increasing excitation force amplitude makes the vibration amplitude increase, the chaotic motion may be restricted. The proposed model and numerical results can be used for diagnosis of faults and vibration control of practical SGRBS.

  10. Nonlinear dynamic analysis of coupled gear-rotor-bearing system with the effect of internal and external excitations

    Zhou, Shihua; Song, Guiqiu; Ren, Zhaohui; Wen, Bangchun

    2016-03-01

    Extensive studies on nonlinear dynamics of gear systems with internal excitation or external excitation respectively have been carried out. However, the nonlinear characteristics of gear systems under combined internal and external excitations are scarcely investigated. An eight-degree-of-freedom(8-DOF) nonlinear spur gear-rotor-bearing model, which contains backlash, transmission error, eccentricity, gravity and input/output torque, is established, and the coupled lateral-torsional vibration characteristics are studied. Based on the equations of motion, the coupled spur gear-rotor-bearing system(SGRBS) is investigated using the Runge-Kutta numerical method, and the effects of rotational speed, error fluctuation and load fluctuation on the dynamic responses are explored. The results show that a diverse range of nonlinear dynamic characteristics such as periodic motion, quasi-periodic motion, chaotic behaviors and impacts exhibited in the system are strongly attributed to the interaction between internal and external excitations. Significantly, the changing rotational speed could effectively control the vibration of the system. Vibration level increases with the increasing error fluctuation. Whereas the load fluctuation has an influence on the nonlinear dynamic characteristics and the increasing excitation force amplitude makes the vibration amplitude increase, the chaotic motion may be restricted. The proposed model and numerical results can be used for diagnosis of faults and vibration control of practical SGRBS.

  11. Offset Compound Gear Drive

    Stevens, Mark A.; Handschuh, Robert F.; Lewicki, David G.

    2010-01-01

    The Offset Compound Gear Drive is an in-line, discrete, two-speed device utilizing a special offset compound gear that has both an internal tooth configuration on the input end and external tooth configuration on the output end, thus allowing it to mesh in series, simultaneously, with both a smaller external tooth input gear and a larger internal tooth output gear. This unique geometry and offset axis permits the compound gear to mesh with the smaller diameter input gear and the larger diameter output gear, both of which are on the same central, or primary, centerline. This configuration results in a compact in-line reduction gear set consisting of fewer gears and bearings than a conventional planetary gear train. Switching between the two output ratios is accomplished through a main control clutch and sprag. Power flow to the above is transmitted through concentric power paths. Low-speed operation is accomplished in two meshes. For the purpose of illustrating the low-speed output operation, the following example pitch diameters are given. A 5.0 pitch diameter (PD) input gear to 7.50 PD (internal tooth) intermediate gear (0.667 reduction mesh), and a 7.50 PD (external tooth) intermediate gear to a 10.00 PD output gear (0.750 reduction mesh). Note that it is not required that the intermediate gears on the offset axis be of the same diameter. For this example, the resultant low-speed ratio is 2:1 (output speed = 0.500; product of stage one 0.667 reduction and stage two 0.750 stage reduction). The design is not restricted to the example pitch diameters, or output ratio. From the output gear, power is transmitted through a hollow drive shaft, which, in turn, drives a sprag during which time the main clutch is disengaged.

  12. Holmes-Adie Syndrome

    ... pupil. Thoracic sympathectomy, which severs the involved sympathetic nerve, is the definitive treatment for excessive sweating. What is the prognosis? Holmes-Adie syndrome is not life-threatening or disabling. The loss of deep tendon reflexes is permanent. Some symptoms of the disorder may ...

  13. Hybrid Gear

    Handschuh, Robert F. (Inventor); Roberts, Gary D. (Inventor)

    2016-01-01

    A hybrid gear consisting of metallic outer rim with gear teeth and metallic hub in combination with a composite lay up between the shaft interface (hub) and gear tooth rim is described. The composite lay-up lightens the gear member while having similar torque carrying capability and it attenuates the impact loading driven noise/vibration that is typical in gear systems. The gear has the same operational capability with respect to shaft speed, torque, and temperature as an all-metallic gear as used in aerospace gear design.

  14. Triple gear

    Schleimer, Saul; Segerman, Henry

    2013-01-01

    A relatively common sight in graphic designs is a planar arrangement of three gears in contact. However, since neighboring gears must rotate in opposite directions, none of the gears can move. We give a non-planar, and non-frozen, arrangement of three linked gears.

  15. Research of the Pressure Angle for Whole Cycloidal Gears

    LIU Ling-tao; WANG Jian-hua

    2011-01-01

    The working profile of whole cycloidal gear is made up of epicycloid and hypocycloid entirely, according to the theory of meshing of gears and the properties of the cycloid, deals with the derivation of the pressure angle formula for the whole cycloidal gear in theory, and reveals changes of the pressure angle of whole cycloidal gear through examples, finds the application relationships between the pressure angle and other design parameters of the whole cycloidal gear, proves the possibility that the whole cycloidal gear can be used in internal parallel move gear mechanism, also provides theoretic fundament for designing internal parallel move whole cycloidal gear correctly.

  16. 新型内平动齿轮减速器的设计%Design of a new internal parallel moving gear reducer

    周利锋; 廖启征; 魏世民; 宋原

    2012-01-01

    在内平动齿轮传动原理的基础上利用平行四边形放缩机构作为外齿轮平动的发生机构,设计了一种新的内平动齿轮减速器.采用周向均布的4套放缩机构驱动两片啮合点相位差为180°的外齿轮,有效地平衡了传动过程中的惯性力.分析了平行四边形放缩机构的最佳传动角.通过分析渐开线少齿差啮合齿轮的干涉,得到了啮合参数的选择依据和计算步骤.最后设计了该减速器的三维实体模型,进行了运动仿真.该减速器具有传动比大、体积小、输入输出同轴线等优点.%Based on internal parallel moving gear drive principle and by using the scaling parallel four-bar linkage as the generator for parallel moving of external gear, a new internal parallel moving gear reducer was designed. Four four-bar linkages equally distributed in circumference were used to drive two external gears with 180° of phase difference at meshing point, and the inertial force during the transmission process was balanced effectively. The optimum transmission angle of the four-bar linkage had been calculated. After analyzing the interference of involute less tooth number difference gear mesh, the constraint condition and calculation procedure were given out. At last, the 3D model of the new gear ret ducer had been designed, and the kinematic simulation had been completed. The new reducer has advantages in large transmission radio, small volume, light weight and coaxial input and output.

  17. A superconducting magnetic gear

    Campbell, A. M.

    2016-05-01

    A comparison is made between a magnetic gear using permanent magnets and superconductors. The objective is to see if there are any fundamental reasons why superconducting magnets should not provide higher power densities than permanent magnets. The gear is based on the variable permeability design of Attilah and Howe (2001 IEEE Trans. Magn. 37 2844-46) in which a ring of permanent magnets surrounding a ring of permeable pole pieces with a different spacing gives an internal field component at the beat frequency. Superconductors can provide much larger fields and forces but will saturate the pole pieces. However the gear mechanism still operates, but in a different way. The magnetisation of the pole pieces is now constant but rotates with angle at the beat frequency. The result is a cylindrical Halbach array which produces an internal field with the same symmetry as in the linear regime, but has an analytic solution. In this paper a typical gear system is analysed with finite elements using FlexPDE. It is shown that the gear can work well into the saturation regime and that the Halbach array gives a good approximation to the results. Replacing the permanent magnets with superconducting tapes can give large increases in torque density, and for something like a wind turbine a combined gear and generator is possible. However there are major practical problems. Perhaps the most fundamental is the large high frequency field which is inevitably present and which will cause AC losses. Also large magnetic fields are required, with all the practical problems of high field superconducting magnets in rotating machines. Nevertheless there are ways of mitigating these difficulties and it seems worthwhile to explore the possibilities of this technology further.

  18. Selective Intracellular Delivery of Recombinant Arginine Deiminase (ADI) Using pH-Sensitive Cell Penetrating Peptides To Overcome ADI Resistance in Hypoxic Breast Cancer Cells.

    Yeh, Tzyy-Harn; Chen, Yun-Ru; Chen, Szu-Ying; Shen, Wei-Chiang; Ann, David K; Zaro, Jennica L; Shen, Li-Jiuan

    2016-01-01

    Arginine depletion strategies, such as pegylated recombinant arginine deiminase (ADI-PEG20), offer a promising anticancer treatment. Many tumor cells have suppressed expression of a key enzyme, argininosuccinate synthetase 1 (ASS1), which converts citrulline to arginine. These tumor cells become arginine auxotrophic, as they can no longer synthesize endogenous arginine intracellularly from citrulline, and are therefore sensitive to arginine depletion therapy. However, since ADI-PEG20 only depletes extracellular arginine due to low internalization, ASS1-expressing cells are not susceptible to treatment since they can synthesize arginine intracellularly. Recent studies have found that several factors influence ASS1 expression. In this study, we evaluated the effect of hypoxia, frequently encountered in many solid tumors, on ASS1 expression and its relationship to ADI-resistance in human MDA-MB-231 breast cancer cells. It was found that MDA-MB-231 cells developed ADI resistance in hypoxic conditions with increased ASS1 expression. To restore ADI sensitivity as well as achieve tumor-selective delivery under hypoxia, we constructed a pH-sensitive cell penetrating peptide (CPP)-based delivery system to carry ADI inside cells to deplete both intra- and extracellular arginine. The delivery system was designed to activate the CPP-mediated internalization only at the mildly acidic pH (6.5-7) associated with the microenvironment of hypoxic tumors, thus achieving better selectivity toward tumor cells. The pH sensitivity of the CPP HBHAc was controlled by recombinant fusion to a histidine-glutamine (HE) oligopeptide, generating HBHAc-HE-ADI. The tumor distribution of HBHAc-HE-ADI was comparable to ADI-PEG20 in a mouse xenograft model of human breast cancer cells in vivo. In addition, HBHAc-HE-ADI showed increased in vitro cellular uptake in cells incubated in a mildly acidic pH (hypoxic conditions) compared to normal pH (normoxic conditions), which correlated with p

  19. Recent ADI iteration analysis and results

    Wachspress, E.L.

    1994-12-31

    Some recent ADI iteration analysis and results are discussed. Discovery that the Lyapunov and Sylvester matrix equations are model ADI problems stimulated much research on ADI iteration with complex spectra. The ADI rational Chebyshev analysis parallels the classical linear Chebyshev theory. Two distinct approaches have been applied to these problems. First, parameters which were optimal for real spectra were shown to be nearly optimal for certain families of complex spectra. In the linear case these were spectra bounded by ellipses in the complex plane. In the ADI rational case these were spectra bounded by {open_quotes}elliptic-function regions{close_quotes}. The logarithms of the latter appear like ellipses, and the logarithms of the optimal ADI parameters for these regions are similar to the optimal parameters for linear Chebyshev approximation over superimposed ellipses. W.B. Jordan`s bilinear transformation of real variables to reduce the two-variable problem to one variable was generalized into the complex plane. This was needed for ADI iterative solution of the Sylvester equation.

  20. NICI: combining coronagraphy, ADI, and SDI

    Artigau, Etienne; Wahhaj, Zahed; Hartung, Markus; Hayward, Thomas L; Close, Laird M; Chun, Mark R; Liu, Michael C; Trancho, Gelys; Rigaut, Francois; Toomeye, Douglas W; Ftaclas, Christ

    2008-01-01

    The Near-Infrared Coronagraphic Imager (NICI) is a high-contrast AO imager at the Gemini South telescope. The camera includes a coronagraphic mask and dual channel imaging for Spectral Differential Imaging (SDI). The instrument can also be used in a fixed Cassegrain Rotator mode for Angular Differential Imaging (ADI). While coronagraphy, SDI, and ADI have been applied before in direct imaging searches for exoplanets. NICI represents the first time that these 3 techniques can be combined. We present preliminary NICI commissioning data using these techniques and show that combining SDI and ADI results in significant gains.

  1. The gears design methods

    Dřevický, Miroslav

    2012-01-01

    Summary: The purpose of this thesis is to present some methods for gear calculation. In the chapter "Design methods for gears" are described four methods of calculation. Detail description of procedure for calculation by using these methods is in this chapter, including designing calculation and checking calculation. There are primary mentioned the calculation methods for a front gears with straight gearing. In the chapter "Calculation of gear set" is the gear set computed by using each meth...

  2. Modern gear production

    Watson, H J

    1970-01-01

    Modern Gear Production focuses on the processes and methods in gear making. The book first gives information on the history of gear making and types of gears. Topics such as the classification of gears based on the disposition of their shafts; shafts lying in the same plane with axes intersecting; and shafts lying in parallel planes but with axes inclined to one another are then discussed. The text describes gear groups, tooth forms, and gear materials. Heat treatment of steels, casehardening, nitriding, induction hardening, sulfinuzing, and flame hardening are explained. The book takes a look

  3. Optimal Design of Internal Gear Shaper Cutter Based on Matlab Genetic Algorithm Optimization Toolbox%基于Matlab遗传算法工具箱的内插齿刀优化设计

    唐德威; 刘丹; 邓宗全; 姜生元

    2012-01-01

    插齿刀参数的选取决定着插齿刀寿命、耐用度和被加工齿轮质量.为了使渐开线内齿轮插齿刀获得更好的切削性能,综合考虑切入顶切、干涉顶切等约束条件,建立了以插齿刀最大重磨厚度、最大变位系数及最大齿数参数为优化目标的数学模型,该模型为插齿刀参数优化设计奠定了基础.在所建立的教学模型基础上,针对传统插齿刀参数优化方法不易全局寻优、速代收敛慢等不足,提出了一种基于Matlab遗传算法工具箱求解渐开线直齿内插齿刀参数的优化设计方法.%The parameter selection of the gear shaper cutter will affect the cutting characters including the service life & endurance of the gear shaper cutter and the quality of the processed gears. By comprehensive consideration of the constraint conditions for cut—in top cut and interfered top cut, a mathematical model is established by taking the parameters such as regrinding thickness of gear shaper cutter, the maximum deflection coefficient and the maximum number of teeth as the optimization objectives in order to enable the gear shaper cutter for inner gears with involute curve to obtain preferable cutting performances. This model has laid the foundation in design for parameter optimization of gear shaper cutter. On the base of established mathematical model and aiming at the deficiency i.e. the traditional parameter optimization method for gear shaper cutter is difficult in global optimization and slow in iterative convergence, this article proposes a new design method to optimize the parameters of the internal gear shaper cutter for processing of the involute straight tooth which is built on the toolbox of Matlab genetic algorithm.

  4. Modular gear bearings

    Vranish, John M. (Inventor)

    2009-01-01

    A gearing system using modular gear bearing components. Each component is composed of a core, one or more modules attached to the core and two or more fastening modules rigidly attaching the modules to the core. The modules, which are attached to the core, may consist of gears, rollers or gear bearing components. The core orientation affects the orientation of the modules attached to the core. This is achieved via the keying arrangement of the core and the component modules that attach to the core. Such an arrangement will also facilitate the phase tuning of gear modules with respect to the core and other gear modules attached to the core.

  5. HIGH EFFICIENCY GEAR

    Florian Ion Tiberiu Petrescu

    2014-04-01

    Full Text Available Normal 0 false false false EN-US X-NONE X-NONE MicrosoftInternetExplorer4 The paper presents an original method for determining gear efficiency, gearing forces, velocities and powers. It analyzes the way in which certain parameters affect gear efficiency. Furthermore, an original method for determining geared transmissions efficiency as a function of the contact ratio is concisely presented. With the presented relations, one can make a dynamic synthesis of geared transmissions with the aim of increasing gearing mechanisms efficiency.

  6. Kinematic geometry of gearing

    Dooner, David B

    2012-01-01

    Building on the first edition published in 1995 this new edition of Kinematic Geometry of Gearing has been extensively revised and updated with new and original material. This includes the methodology for general tooth forms, radius of torsure', cylinder of osculation, and cylindroid of torsure; the author has also completely reworked the '3 laws of gearing', the first law re-written to better parallel the existing 'Law of Gearing" as pioneered by Leonard Euler, expanded from Euler's original law to encompass non-circular gears and hypoid gears, the 2nd law of gearing describing a unique relat

  7. Anti-backlash gear bearings

    Vranish, John M. (Inventor)

    2009-01-01

    A gear bearing having a first gear and a second gear, each having a plurality of teeth. Each gear operates on two non-parallel surfaces of the opposing gear teeth to perform both gear and bearing functions simultaneously. The gears are moving at substantially the same speed at their contact points. The gears may be roller gear bearings or phase-shifted gear bearings, and may be arranged in a planet/sun system or used as a transmission. One preferred embodiment discloses and describes an anti-backlash feature to counter ''dead zones'' in the gear bearing movement.

  8. Noncircular gears design and generation

    Litvin, Faydor L; Gonzalez-Perez, Ignacio

    2009-01-01

    Noncircular Gears: Design and Generation represents the extension of the modern theory of gearing applied to the design and manufacture of the main types of noncircular gears: conventional and modified elliptical gears, eccentric gears, oval gears, gears with lobes, and twisted gears. This book is enhanced by updated theoretical description of the methods of generation of noncircular gears by enveloping methods similar to those applied to the generation of circular gears. Noncircular Gears: Design and Generation also offers new developments directed to extend the application of noncircular gea

  9. AERODYNAMIC IMPROVEMENT OF KhADI 33 RACING CAR RADIATOR COMPARTMENT

    A. Avershyn

    2011-01-01

    Full Text Available Aerodynamic characteristics of radiator compartment of KhADI 33 racing car on the basis of the decision of the interfaced problem of internal and external aerodynamics are numerically investigated. The rational variant of radiator compartment which is characterized by high throughput and low level of non-uniformity of speed field at the input is offered.

  10. ELASTIC-PLASTIC BEHAVIOUR OF ADVANCED ADI STUDIED BY IN-SITU SEM TENSILE TEST

    Petrenec, M.; Tesařová, H.; Krahula, Karel; Polák, Jaroslav

    Ostrava: TANGER Ltd, 2013, s. 676-681. ISBN 978-80-87294-41-3. [METAL 2013 - International Conference on Metallurgy and Materials /22./. Brno (CZ), 15.05.2013-17.05.2013] Institutional support: RVO:68081723 Keywords : ADI with nickel alloying * in-situ tensile test * mechanical properties * deformation mechanisms * SEM-FEG Subject RIV: JL - Materials Fatigue, Friction Mechanics

  11. Gear bearing drive

    Weinberg, Brian (Inventor); Mavroidis, Constantinos (Inventor); Vranish, John M. (Inventor)

    2011-01-01

    A gear bearing drive provides a compact mechanism that operates as an actuator providing torque and as a joint providing support. The drive includes a gear arrangement integrating an external rotor DC motor within a sun gear. Locking surfaces maintain the components of the drive in alignment and provide support for axial loads and moments. The gear bearing drive has a variety of applications, including as a joint in robotic arms and prosthetic limbs.

  12. Estimating Gear Teeth Stiffness

    Pedersen, Niels Leergaard

    2013-01-01

    The estimation of gear stiffness is important for determining the load distribution between the gear teeth when two sets of teeth are in contact. Two factors have a major influence on the stiffness; firstly the boundary condition through the gear rim size included in the stiffness calculation and...

  13. Landing gear noise attenuation

    Moe, Jeffrey W. (Inventor); Whitmire, Julia (Inventor); Kwan, Hwa-Wan (Inventor); Abeysinghe, Amal (Inventor)

    2011-01-01

    A landing gear noise attenuator mitigates noise generated by airframe deployable landing gear. The noise attenuator can have a first position when the landing gear is in its deployed or down position, and a second position when the landing gear is in its up or stowed position. The noise attenuator may be an inflatable fairing that does not compromise limited space constraints associated with landing gear retraction and stowage. A truck fairing mounted under a truck beam can have a compliant edge to allow for non-destructive impingement of a deflected fire during certain conditions.

  14. Estimating Gear Teeth Stiffness

    Pedersen, Niels Leergaard

    2013-01-01

    The estimation of gear stiffness is important for determining the load distribution between the gear teeth when two sets of teeth are in contact. Two factors have a major influence on the stiffness; firstly the boundary condition through the gear rim size included in the stiffness calculation and secondly the size of the contact. In the FE calculation the true gear tooth root profile is applied. The meshing stiffness’s of gears are highly non-linear, it is however found that the stiffness of ...

  15. Operator experiences with international safeguards in the back end of the fuel cycle-geared to economic efficiency

    The nuclear industry in the Federal Republic of Germany (FRG) started at an early date to close the nuclear fuel cycle. Today, facilities operate for the enrichment of 235U, for its conversion, and for the fabrication of both uranium and uranium-plutonium mixed-oxide fuel elements. Pilot plants for the chemical processing of spent-fuel elements, as well as for the vitrification of the highly radioactive waste solutions, are also being operated on an industrial scale. This development has been generously sponsored by the Federal Minister of Research and Technology. This paper, which reports on the commitment of industry in the FRG to close the back end of the nuclear fuel cycle and the interaction of industrial activities with international safeguards, includes a discussion of efforts to implement a second way of entsorgung, the direct disposal of spent-fuel elements. International safeguards in German nuclear installations have proven to be sufficient to provide a high degree of guarantee against diversion at the various stages of the fuel cycle. Moreover, the state of the art that has been achieved and the improvements discussed will enable both the inspectorates and the operator to exercise efficient safeguards in future plants, including bulk-handling facilities, without impairing the economy of operation of the facilities

  16. Landing Gear Door Liners for Airframe Noise Reduction

    Jones, Michael G. (Inventor); Howerton, Brian M. (Inventor); Van De Ven, Thomas (Inventor)

    2014-01-01

    A landing gear door for retractable landing gear of aircraft includes an acoustic liner. The acoustic liner includes one or more internal cavities or chambers having one or more openings that inhibit the generation of sound at the surface and/or absorb sound generated during operation of the aircraft. The landing gear door may include a plurality of internal chambers having different geometries to thereby absorb broadband noise.

  17. Microadditions of boron and vanadium in ADI

    Rzychoń T.

    2007-01-01

    Full Text Available In the second part of the study, describing the role of vanadium and boron microadditions in the process of structure formation in heavy-walled castings made from ADI, the results of own investigations were presented. Within this study two series of melts of the ductile iron were made, introducing microadditions of the above mentioned elements to both unalloyed ductile iron and the ductile iron containing high levels of nickel and copper (the composition typical of ADI. Melts were conducted with iron-nickel-magnesium master alloy. Thermal analysis of the solidification process of the cast keel blocks was conducted, the heat treatment of the alloys was carried out, and then the effect of the introduced additions of boron and vanadium on the hardenability of the investigated cast iron was examined and evaluated.

  18. Modeling of the process of gear shifting in planetary gear trains of motor vehicles

    Aleksandar R. Grkić

    2011-04-01

    Full Text Available Gear boxes, i. e. the realization of their functions, especially gear shift, have a big impact on vehicle operation quality through their effects on the performance of vehicles and their comfort. This paper shows a method of modeling the transition process during gear shifting in planetary gear trains. The simulation model is developed with in order to provide virtual research of planetary gear trains, which would positively decrease the number of real prototypes, thus considerably saving time and contributing to the quality improvement of the final product (planetary gear train and vehicles in general. Introduction Modeling of gear shift processes has been carried out on the planetary gear type Ravigneaux used in planetary gear trains of motor vehicles. The model was developed modularly, so that more simulation models can be added to the whole. At the same time each subsystem is a model for itself and can be used independently from the main model. Simplified engine model Bearing in mind that, for the simulation of the planetary gear which is the subject of this paper, the necessary input parameters are in the form of engine torque Mm, angular velocity and motor ωm moment of inertia of rotating engine components reduced to the input shaft gear, a simplified model of an internal combustion engine has been formed. Model of external load External load resistance is in the form of the torque Mt occurring on the drive wheel of the vehicle. On the other hand, this load is defined by the moment of inertia of rotating elements from the planetary gear to the drive wheel, reduced to the output shaft. Model of friction transmission simulation Transmission power control in planetary gears is achieved through friction components. The output size of this subsystem is the moment of carrying the friction assembly. Simulation model of the planetary gear train The model simulation of the planetary gear type Ravigneaux was formed in accordance with the kinematic

  19. Unique microstructure and excellent mechanical properties of ADI

    Jincheng Liu

    2006-01-01

    Amongst the cast iron family, ADI has a unique microstructure and an excellent, optimised combination of mechanical properties. The main microstructure of ADI is ausferrite, which is a mixture ofextremely fine acicular ferrite and stable, high carbon austenite. There are two types of austenite in ADI:(1) the coarser and more equiaxed blocks of austenite between non-parallel acicular structures, which exist mainly in the last solidified area, and (2) the thin films of ustenite between the indi...

  20. ADI After Austenitising From Intercritical Temperature

    A. Kowalski; S. Kloska-Nawarecka; Regulski, K.

    2013-01-01

    ADI subjected to austenitising at intercritical temperatures contains in its matrix the precipitates of pre-eutectoid ferrite. Studies were carried out on the ductile iron of the following chemical composition: C = 3,80%, Si = 2,30%, Mn = 0,28%, P = 0,060%, S = 0,010%, Mg = 0,065%, Ni = 0,60%, Cu = 0,70%, Mo = 0,21% This cast iron was austenitised at three different temperatures, i.e. 800, 815 and 830oC and austempered at 360 and 380oC. For each variant of the cast iron heat treatment, the me...

  1. Gear Crack Propagation Investigation

    1995-01-01

    Reduced weight is a major design goal in aircraft power transmissions. Some gear designs incorporate thin rims to help meet this goal. Thin rims, however, may lead to bending fatigue cracks. These cracks may propagate through a gear tooth or into the gear rim. A crack that propagates through a tooth would probably not be catastrophic, and ample warning of a failure could be possible. On the other hand, a crack that propagates through the rim would be catastrophic. Such cracks could lead to disengagement of a rotor or propeller from an engine, loss of an aircraft, and fatalities. To help create and validate tools for the gear designer, the NASA Lewis Research Center performed in-house analytical and experimental studies to investigate the effect of rim thickness on gear-tooth crack propagation. Our goal was to determine whether cracks grew through gear teeth (benign failure mode) or through gear rims (catastrophic failure mode) for various rim thicknesses. In addition, we investigated the effect of rim thickness on crack propagation life. A finite-element-based computer program simulated gear-tooth crack propagation. The analysis used principles of linear elastic fracture mechanics, and quarter-point, triangular elements were used at the crack tip to represent the stress singularity. The program had an automated crack propagation option in which cracks were grown numerically via an automated remeshing scheme. Crack-tip stress-intensity factors were estimated to determine crack-propagation direction. Also, various fatigue crack growth models were used to estimate crack-propagation life. Experiments were performed in Lewis' Spur Gear Fatigue Rig to validate predicted crack propagation results. Gears with various backup ratios were tested to validate crack-path predictions. Also, test gears were installed with special crack-propagation gages in the tooth fillet region to measure bending-fatigue crack growth. From both predictions and tests, gears with backup ratios

  2. Partial tooth gear bearings

    Vranish, John M. (Inventor)

    2010-01-01

    A partial gear bearing including an upper half, comprising peak partial teeth, and a lower, or bottom, half, comprising valley partial teeth. The upper half also has an integrated roller section between each of the peak partial teeth with a radius equal to the gear pitch radius of the radially outwardly extending peak partial teeth. Conversely, the lower half has an integrated roller section between each of the valley half teeth with a radius also equal to the gear pitch radius of the peak partial teeth. The valley partial teeth extend radially inwardly from its roller section. The peak and valley partial teeth are exactly out of phase with each other, as are the roller sections of the upper and lower halves. Essentially, the end roller bearing of the typical gear bearing has been integrated into the normal gear tooth pattern.

  3. 78 FR 68432 - Applicability Determination Index (ADI) Database System Recent Posting: Applicability...

    2013-11-14

    ... AGENCY Applicability Determination Index (ADI) Database System Recent Posting: Applicability... the Applicability Determination Index (ADI) database system is available on the Internet through the... for each document posted on the ADI database system on October 30, 2013; the applicable category;...

  4. 50 CFR 665.127 - Allowable gear and gear restrictions.

    2010-10-01

    ... 50 Wildlife and Fisheries 9 2010-10-01 2010-10-01 false Allowable gear and gear restrictions. 665.127 Section 665.127 Wildlife and Fisheries FISHERY CONSERVATION AND MANAGEMENT, NATIONAL OCEANIC AND... Fisheries § 665.127 Allowable gear and gear restrictions. (a) American Samoa coral reef ecosystem MUS may...

  5. 50 CFR 665.627 - Allowable gear and gear restrictions.

    2010-10-01

    ... 50 Wildlife and Fisheries 9 2010-10-01 2010-10-01 false Allowable gear and gear restrictions. 665.627 Section 665.627 Wildlife and Fisheries FISHERY CONSERVATION AND MANAGEMENT, NATIONAL OCEANIC AND... Island Area Fisheries § 665.627 Allowable gear and gear restrictions. (a) Coral reef ecosystem MUS may...

  6. 50 CFR 665.427 - Allowable gear and gear restrictions.

    2010-10-01

    ... 50 Wildlife and Fisheries 9 2010-10-01 2010-10-01 false Allowable gear and gear restrictions. 665.427 Section 665.427 Wildlife and Fisheries FISHERY CONSERVATION AND MANAGEMENT, NATIONAL OCEANIC AND... Archipelago Fisheries § 665.427 Allowable gear and gear restrictions. (a) Mariana coral reef ecosystem MUS...

  7. 50 CFR 665.227 - Allowable gear and gear restrictions.

    2010-10-01

    ... 50 Wildlife and Fisheries 9 2010-10-01 2010-10-01 false Allowable gear and gear restrictions. 665.227 Section 665.227 Wildlife and Fisheries FISHERY CONSERVATION AND MANAGEMENT, NATIONAL OCEANIC AND... Fisheries § 665.227 Allowable gear and gear restrictions. (a) Hawaii coral reef ecosystem MUS may be...

  8. Research of HCR Gearing Properties from Warm Scuffing Damage Point of View

    Kuzmanović Siniša

    2014-12-01

    Full Text Available The issue of design and dimensioning of HCR gearing, particularly of the gearings with an internal engagement, it nowadays, especially in the design of hybrid cars drives, highly topical. This kind of gearing has many advantages in operation, but at the same time it is more complicated in stage of its design and load capacity calculation. Authors in this contribution present some results of temperature scuffing research of internal and external HCR gearing. There are given the equations for calculation of warm scuffing resistance of both external and internal HCR gearing derived according to the integral temperature criterion.

  9. ADI After Austenitising From Intercritical Temperature

    A. Kowalski

    2013-01-01

    Full Text Available ADI subjected to austenitising at intercritical temperatures contains in its matrix the precipitates of pre-eutectoid ferrite. Studies were carried out on the ductile iron of the following chemical composition: C = 3,80%, Si = 2,30%, Mn = 0,28%, P = 0,060%, S = 0,010%, Mg = 0,065%, Ni = 0,60%, Cu = 0,70%, Mo = 0,21% This cast iron was austenitised at three different temperatures, i.e. 800, 815 and 830oC and austempered at 360 and 380oC. For each variant of the cast iron heat treatment, the mechanical properties, i.e. YS, TS, EL and Hardness, were measured, and structure of the matrix was examined. Higher plastic properties were obtained owing to the presence of certain amount of pre-eutectoid ferrite. The properties were visualised using fuzzy logic model in a MATLAB. software.

  10. Review on common calibration and measurement practises for measuring gears on CMMs

    Sammatini-Malberg, Maria-Pia; De Chiffre, Leonardo

    The present report reviews the state of the art of metrology of cylindrical gears with involute toothing. The subjects covered in the state of the art range from gear measuring instruments to gear standards, together with a general introduction to international and national standards and guidelin...

  11. The cycloid Permanent Magnetic Gear

    Rasmussen, Peter Omand; Andersen, Torben Ole; Jørgensen, Frank T.

    2008-01-01

    This paper presents a new permanent-magnet gear based on the cycloid gearing principle. which normally is characterized by an extreme torque density and a very high gearing ratio. An initial design of the proposed magnetic gear was designed, analyzed, and optimized with an analytical model...... regarding torque density. The results were promising as compared to other high-performance magnetic-gear designs. A test model was constructed to verify the analytical model....

  12. Communication: Molecular gears.

    Burnell, E Elliott; de Lange, Cornelis A; Meerts, W Leo

    2016-09-01

    The (1)H nuclear magnetic resonance spectrum of hexamethylbenzene orientationally ordered in the nematic liquid crystal ZLI-1132 is analysed using covariance matrix adaptation evolution strategy. The spectrum contains over 350 000 lines with many overlapping transitions, from which four independent direct dipolar couplings are obtained. The rotations of the six methyl groups appear to be correlated due to mutual steric hindrance. Adjacent methyl groups show counter-rotating or geared motion. Hexamethylbenzene thus behaves as a molecular hexagonal gear. PMID:27608981

  13. Landing-gear impact

    Flugge, W

    1952-01-01

    Report deals with the impact forces in landing gears. Both the landing impact and the taxiing impact have been considered, but drag forces have so far been excluded. The differential equations are developed and their numerical integration is shown, considering the nonlinear properties of the oleo shock strut. A way is shown for determining the dimensions of the metering pin from a given load-time diagram. A review of German literature on landing-gear impact is also presented.

  14. Unique microstructure and excellent mechanical properties of ADI

    Jincheng Liu

    2006-11-01

    Full Text Available Amongst the cast iron family, ADI has a unique microstructure and an excellent, optimised combination of mechanical properties. The main microstructure of ADI is ausferrite, which is a mixture ofextremely fine acicular ferrite and stable, high carbon austenite. There are two types of austenite in ADI:(1 the coarser and more equiaxed blocks of austenite between non-parallel acicular structures, which exist mainly in the last solidified area, and (2 the thin films of ustenite between the individual ferriteplatelets in the acicular structure. It is this unique microstructure, which gives ADI its excellent static and dynamic properties, and good low temperature impact toughness. The effect of microstructure on the mechanical properties is explained in more detail by examining the microstructure at the atomic scale. Considering the nanometer grain sizes, the unique microstructure, the excellent mechanical properties,good castability, (which enables near net shape components to be produced economically and in large volumes, and the fact that it can be 100% recycled, it is not overemphasized to call ADI a high-tech,nanometer and “green” material. ADI still has the potential to be further improved and its production and the number of applications for ADI will continue to grow, driven by the resultant cost savings over alternative materials.

  15. An anti-backlash designed planetary gear mechanism: description of general planar motion using matrix methods

    Vojtěch Klouček; Stanislav Prýl; Veronika Šulcová

    2015-01-01

    Design of the integrated gear mechanism so arranged that to the three-phase asynchronous motor chassis with a squirrel cage is integrated gear mechanism with internal teeth. In order to eliminate all the backlashes in the gearing and bearings, is branched into two identical gears, between which is inserted the flexible component.The kinematics of bodies, which held general planar motion, are solved by matrix methods of investigation of constrained multibody systems.

  16. 二齿差纯滚动活齿内齿圈的数字化设计与加工%Digital Design and Manufacturing on New Two-tooth Difference Pure Rolling Movable Teeth Internal Gear

    张帅; 梁尚明; 蒋立茂; 张杰; 姚进

    2012-01-01

    Aimingat the problem of the low machining precision and manufacturing difficulties of the new two-tooth difference pure rolling internal gear profile,α method of 3D digital design and manufacturing was proposed based on UG NX design platfomuThree-dimensional modeling of the internal gear profile was established though envelope equationAnd the tooth profile was analyzed and digital processing was illustrated in detail With the help of UG NX design platform,the problems in manufacturing procession were effectively solved,which reduced costs in product design and production and improved work efficiency.Though NC machine cutting simulation,the risk of parts false processing was reduced.The digital design and manufacturing based on UG NX design platform provided a new method for the design and manufacture of internal gear.%针对新型二齿差纯滚动活齿内齿圈轮廓曲线加工精度低,加工难度大的问题,提出了基于UG NX设计平台的三维数字化设计与加工的方法.通过二齿差纯滚动滚柱活齿外端曲线的包络方程,在UG NX设计平台对内齿圈三维建模.对齿形进行了分析并对数字化加工做了详细的说明.借助UG NX设计平台,有效解决了内齿圈加工过程中的难题,降低了产品设计、生产成本,提高了工作效率.通过数控机床的切削仿真,降低了零件加工错误的风险.UG NX设计平台的数字化设计与加工为内齿圈的设计与制造提供了新的方法.

  17. Gear checker analysis and evaluation using a virtual gear checker

    The vibration of gears is one of the serious problems for machines. The characteristics of vibration of gears are considerably affected by the tooth flank form deviation of micrometer order; therefore, strict quality control of the tooth flank form is required. However, because the gear checker (a gear-measuring machine) is structurally complex, it is difficult to analyze how the error factors of the gear checkers affect the measurement result. In this research, a virtual gear checker (VGC) is proposed, that is, a computer program that considers the structures, motions and possible error factors of the real gear checkers, such as motion error. The VGC can be used to simulate the gear measurement, and the effects of the error factors on the measurement result can be analyzed. It is possible to evaluate the uncertainty of tooth flank measurement much more easily and quickly with a VGC than with a real gear checker. A VGC can be used to analyze not only the gear measurement but also arbitrary-shaped objects such as a ball artefact, and the theoretical measurement result is output from the VGC. In this paper, we describe the development of a VGC, and the effect of error factors and the uncertainties of gear measurement are analyzed

  18. On gear tooth stiffness evaluation

    Pedersen, Niels Leergaard; Jørgensen, Martin Felix

    2014-01-01

    The estimation of gear stiffness is important for determining the load distribution between the gear teeth when two sets of teeth are in contact. Two factors have a major influence on the stiffness; firstly the boundary condition through the gear rim size included in the stiffness calculation and...... secondly the size of the contact. In the FE calculation the true gear tooth root profile is applied. The meshing stiffnesses of gears are highly non-linear, it is however found that the stiffness of an individual tooth can be expressed in a linear form assuming that the contact width is constant. © 2014...

  19. Bevel gear fundamentals and applications

    2016-01-01

    This is the first book to offer a complete presentation of bevel gears. An expert team of authors highlights the areas of application for these machine elements and presents the geometrical features of bevel gears as well as the various gear cutting processes based on gear cutting theory. The aspect of three-dimensional gearing is assessed in detail in terms of flank design, load capacity and noise behavior. A representation of production processes with the required technologies provides a knowledge base on which sound decisions can be based. The authors offer a thorough introduction to the complex world of bevel gears and present the rapid advances of these machine elements in a detailed, comprehensible manner.  This book addresses design engineers in mechanical engineering and vehicle manufacturing, as well as producers of bevel gears and students in mechanical engineering.

  20. p-adična števila

    Grešak, Rozalija

    2015-01-01

    Realna števila običajno vpeljemo s pomočjo Dedekindovih rezov. V magistrskem delu se osredotočimo na konstrukcijo realnih števil s pomočjo metrične napolnitve racionalnih števil, torej s pomočjo Cauchyjevih zaporedij. Nato na podoben način konstruiramo p-adična števila, opišemo njihove glavne značilnosti in nekaj njihovih topoloških lastnosti. V nadaljevanju opišemo konstrukcijo kompleksnih p-adičnih števil in primerjamo običajna kompleksna števila s p-adičnimi kompleksnimi števili. Magistrsk...

  1. Energy efficiency improvement by gear shifting optimization

    Blagojevic Ivan A.

    2013-01-01

    Full Text Available Many studies have proved that elements of driver’s behavior related to gear selection have considerable influence on the fuel consumption. Optimal gear shifting is a complex task, especially for inexperienced drivers. This paper presents an implemented idea for gear shifting optimization with the aim of fuel consumption minimization with more efficient engine working regimes. Optimized gear shifting enables the best possible relation between vehicle motion regimes and engine working regimes. New theoretical-experimental approach has been developed using On-Board Diagnostic technology which so far has not been used for this purpose. The matrix of driving modes according to which tests were performed is obtained and special data acquisition system and analysis process have been developed. Functional relations between experimental test modes and adequate engine working parameters have been obtained and all necessary operations have been conducted to enable their use as inputs for the designed algorithm. The created Model has been tested in real exploitation conditions on passenger car with Otto fuel injection engine and On-Board Diagnostic connection without any changes on it. The conducted tests have shown that the presented Model has significantly positive effects on fuel consumption which is an important ecological aspect. Further development and testing of the Model allows implementation in wide range of motor vehicles with various types of internal combustion engines.

  2. Dynamic Modeling and Chaotic Analysis of Gear Transmission System in a Braiding Machine with or without Random Perturbation

    Zhang Yujing; Meng Zhuo; Sun Yize

    2016-01-01

    This paper is aimed at analyzing the dynamic behavior of the gear transmission system in a braiding machine. In order to observe the nonlinear phenomenon and reveal the time-varying gear meshing mechanism, a mathematical model with five degrees-of-freedom gear system under internal and external random disturbance of gear system is established. With this model, bifurcation diagrams, Poincare maps, phase diagrams, power spectrum, time-process diagrams, and Lyapunov exponents are used to identif...

  3. Design and construction of permanent magnetic gears

    Jørgensen, Frank Thorleif

    This thesis deals with design and development of permanent magnetic gears. The goal of this thesis is to develop knowledge and calculation software for magnetic gears. They use strong NdFeB permanent magnets and a new magnetic gear technology, which will be a serious alternative to classical....... This magnetic gear type is searched and only a single reference [74] is found and that is why the combination of a cycloidal gear and a magnetic gear are considered as an innovative supplement to magnetic gear technology. A magnetic cycloidal gear is designed with a gearing of 1:21 and a calculated...

  4. APPLICATION OF ASYMMETRIC PROFILE IN GEARINGS WITH ECCENTRIC GEARS

    Silvia MEDVECKÁ-BEŇOVÁ

    2014-12-01

    Full Text Available Gearing was designed to meet specific requirement, during one rotation was continuous change of gear ratio. The gearing consists of two identical gears. The basic shape of the wheel is formed by an ellipse. One of the foci is the center of rotation. Wheels are designed for only one direction of rotation. Active and passive side involute curve were created by rolling the basic evoluta elliptical wheel independently. It was used for the production of NC cutting machine for EDM 005 B EIR with managing RS-ER5. This machine allows you to create a constructed shape gears, keeping the necessary accuracy of 0.01 mm and roughness of Ra 1.6 micron. The basic of production, a draft gear was designed using AutoCAD software. Thus follows designed and manufactured elliptical gearing was subjected to the tests and meets all the requirements that were imposed on the gear. Proportion loads of teeth are different from the standard load of circular gears.

  5. APPLICATION OF ASYMMETRIC PROFILE IN GEARINGS WITH ECCENTRIC GEARS

    Silvia MEDVECKÁ-BEŇOVÁ; Vojtková, Jarmila

    2014-01-01

    Gearing was designed to meet specific requirement, during one rotation was continuous change of gear ratio. The gearing consists of two identical gears. The basic shape of the wheel is formed by an ellipse. One of the foci is the center of rotation. Wheels are designed for only one direction of rotation. Active and passive side involute curve were created by rolling the basic evoluta elliptical wheel independently. It was used for the production of NC cutting machine for EDM 005 B EIR with ma...

  6. The comparative studies of ADI versus Hadfield cast steel wear resistance

    Mieczysław Kaczorowski

    2011-04-01

    Full Text Available The results of comparative studies of wear resistance of ADI versus high manganese Hadfield cast steel are presented. For evaluation ofwear resistance three type of ADI were chosen. Two of them were of moderate strength ADI with 800 and 1000MPa tensile strength whilethe third was 1400MPa tensile strength ADI. The specimens were cut from ADI test YII type casting poured and heat treated in Institute ofFoundry in Krakow. The pin on disc method was used for wear resistance experiment. The specimens had a shape of 40mm long rod withdiameter 6mm. The load and speed were 100N and 0,54m/s respectively. It was concluded that the wear resistance of ADI is comparablewith high manganese cast steel and in case of low tensile grade ADI and is even better for high strength ADI than Hadfield steel.

  7. 49 CFR 230.89 - Reverse gear.

    2010-10-01

    ... 49 Transportation 4 2010-10-01 2010-10-01 false Reverse gear. 230.89 Section 230.89 Transportation... Reversing Gear § 230.89 Reverse gear. (a) General provisions. Reverse gear, reverse levers, and quadrants... quadrant. Proper counterbalance shall be provided for the valve gear. (b) Air-operated power reverse...

  8. 46 CFR 28.885 - Cargo gear.

    2010-10-01

    ... 46 Shipping 1 2010-10-01 2010-10-01 false Cargo gear. 28.885 Section 28.885 Shipping COAST GUARD... Aleutian Trade Act Vessels § 28.885 Cargo gear. (a) The safe working load (SWL) for the assembled gear... the load the gear is approved to lift, excluding the weight of the gear itself. (b) All wire...

  9. Negative stiffness in gear contact

    Půst, Ladislav; Pešek, Luděk; Radolfová, Alena

    Plzeň : University of West Bohemia, 2015 - (Adámek, V.). s. 93-94 ISBN 978-80-261-0568-8. [Computational Mechanics 2015 /31./. 09.11.2015-11.11.2015, Špičák] R&D Projects: GA TA ČR TA04011656 Institutional support: RVO:61388998 Keywords : gear box * planetary gear s * gear trains * radial contact stiffness Subject RIV: BI - Acoustics

  10. Research on synchronous gear pump

    LUAN Zhen-hui

    2010-01-01

    Based on a comprehensive analysis of the structure and existing problems of the gear pump, provided a structure principle of a synchronous gear pump. The discussions focused on the working principle, construction features and finite element analysis of the hydraulic gear. The research indicates that the new pump has such advantages as lower noise, better distributed flow and a high work pressure, and it can be widely used in hydraulic systems.

  11. Ideally Efficient Irreversible Molecular Gears

    Sokolov, I. M.

    2000-01-01

    Typical man-made locomotive devices use reversible gears, as cranks, for transforming reciprocating motion into directed one. Such gears are holonomic and have the transduction efficiency of unity. On the other hand, a typical gear of molecular motors is a ratchet rectifier, which is irreversible. We discuss what properties of rectifier mostly influence the transduction efficiency and show that an apliance which locks under backwards force can achieve the energetic efficiency of unity, withou...

  12. Gears Based on Carbon Nanotubes

    Jaffe, Richard; Han, Jie; Globus, Al; Deardorff, Glenn

    2005-01-01

    Gears based on carbon nanotubes (see figure) have been proposed as components of an emerging generation of molecular- scale machines and sensors. In comparison with previously proposed nanogears based on diamondoid and fullerene molecules, the nanotube-based gears would have simpler structures and are more likely to be realizable by practical fabrication processes. The impetus for the practical development of carbon-nanotube- based gears arises, in part, from rapid recent progress in the fabrication of carbon nanotubes with prescribed diameters, lengths, chiralities, and numbers of concentric shells. The shafts of the proposed gears would be made from multiwalled carbon nanotubes. The gear teeth would be rigid molecules (typically, benzyne molecules), bonded to the nanotube shafts at atomically precise positions. For fabrication, it may be possible to position the molecular teeth by use of scanning tunneling microscopy (STM) or other related techniques. The capability to position individual organic molecules at room temperature by use of an STM tip has already been demonstrated. Routes to the chemical synthesis of carbon-nanotube-based gears are also under investigation. Chemical and physical aspects of the synthesis of molecular scale gears based on carbon nanotubes and related molecules, and dynamical properties of nanotube- based gears, have been investigated by computational simulations using established methods of quantum chemistry and molecular dynamics. Several particularly interesting and useful conclusions have been drawn from the dynamical simulations performed thus far: The forces acting on the gears would be more sensitive to local molecular motions than to gross mechanical motions of the overall gears. Although no breakage of teeth or of chemical bonds is expected at temperatures up to at least 3,000 K, the gears would not work well at temperatures above a critical range from about 600 to about 1,000 K. Gear temperature could probably be controlled by

  13. Gears, Pregears and Related Domains

    Brown, Philip R.; Porter, R. Michael

    2015-01-01

    We study conformal mappings from the unit disk to one-toothed gear-shaped planar domains from the point of view of the Schwarzian derivative. Gear-shaped (or "gearlike") domains fit into a more general category of domains we call "pregears" (images of gears under Mobius transformations), which aid in the study of the conformal mappings for gears and which we also describe in detail. Such domains being bounded by arcs of circles, the Schwarzian derivative of the Riemann mapping is known to be ...

  14. High Pressure Angle Gears: Comparison to Typical Gear Designs

    Handschuh, Robert F.; Zabrajsek, Andrew J.

    2010-01-01

    A preliminary study has been completed to determine the feasibility of using high-pressure angle gears in aeronautic and space applications. Tests were conducted in the NASA Glenn Research Center (GRC) Spur Gear Test Facility at speeds up to 10,000 rpm and 73 N*m (648 in.*lb) for 3.18, 2.12, and 1.59 module gears (8, 12, and 16 diametral pitch gears), all designed to operate in the same test facility. The 3.18 module (8-diametral pitch), 28 tooth, 20deg pressure angle gears are the GRC baseline test specimen. Also, 2.12 module (12-diametral pitch), 42 tooth, 25deg pressure angle gears were tested. Finally 1.59 module (16-diametral pitch), 56 tooth, 35deg pressure angle gears were tested. The high-pressure angle gears were the most efficient when operated in the high-speed aerospace mode (10,000 rpm, lubricated with a synthetic turbine engine oil), and produced the lowest wear rates when tested with a perfluoroether-based grease. The grease tests were conducted at 150 rpm and 71 N*m (630 in.*lb).

  15. Double Helical Gear Performance Results in High Speed Gear Trains

    Handschuh, Robert F.; Ehinger, Ryan; Sinusas, Eric; Kilmain, Charles

    2010-01-01

    The operation of high speed gearing systems in the transmissions of tiltrotor aircraft has an effect on overall propulsion system efficiency. Recent work has focused on many aspects of high-speed helical gear trains as would be used in tiltrotor aircraft such as operational characteristics, comparison of analytical predictions to experimental data and the affect of superfinishing on transmission performance. Baseline tests of an aerospace quality system have been conducted in the NASA Glenn High-Speed Helical Gear Train Test Facility and have been described in earlier studies. These earlier tests had utilized single helical gears. The results that will be described in this study are those attained using double helical gears. This type of gear mesh can be configured in this facility to either pump the air-oil environment from the center gap between the meshing gears to the outside of tooth ends or in the reverse direction. Tests were conducted with both inward and outward air-oil pumping directions. Results are compared to the earlier baseline results of single helical gears.

  16. Gearing Up for the Fair——Promoters are attracting overseas attention to the upcoming annual international investment and trade fair in Xiamen,southeast China

    2006-01-01

    As the 10th China International Fair for Investment and Trade (CIFIT) draws near, a variety of promotional events are being intensively planned by the CIFIT organizing committee. The fair starts September 8, and in a bid to further raise the level of the exposition and better integrate it into the

  17. The comparative studies of ADI versus Hadfield cast steel wear resistance

    Mieczysław Kaczorowski; Anna Krzyńska; Paweł Skoczylas

    2011-01-01

    The results of comparative studies of wear resistance of ADI versus high manganese Hadfield cast steel are presented. For evaluation ofwear resistance three type of ADI were chosen. Two of them were of moderate strength ADI with 800 and 1000MPa tensile strength whilethe third was 1400MPa tensile strength ADI. The specimens were cut from ADI test YII type casting poured and heat treated in Institute ofFoundry in Krakow. The pin on disc method was used for wear resistance experiment. The specim...

  18. The changes of ADI structure during high temperature annealing

    A. Krzyńska

    2010-01-01

    Full Text Available The results of structure investigations of ADI during it was annealing at elevated temperature are presented. Ductile iron austempered at temperature 325oC was then isothermally annealed 360 minutes at temperature 400, 450, 500 and 550oC. The structure investigations showed that annealing at these temperatures caused substantial structure changes and thus essential hardness decrease, which is most useful property of ADI from point of view its practical application. Degradation advance of the structure depends mainly on annealing temperature, less on the time of the heat treatment. It was concluded that high temperature annealing caused precipitation of Fe3C type carbides, which morphology and distribution depend on temperature. In case of 400oC annealing the carbides precipitates inside bainitic ferrite lath in specific crystallographic planes and partly at the grain boundaries. The annealing at the temperature 550oC caused disappearing of characteristic for ADI needle or lath – like morphology, which is replaced with equiaxed grains. In this case Fe3C carbides take the form very fine precipitates with spheroidal geometry.

  19. Mechanical properties and structure of austempered ductile iron -ADI

    Krzyńska A.

    2007-01-01

    Full Text Available The results of experimental study of austempered ductile iron are presented. The aim of the investigations was to look closer into the structure – mechanical properties relationships of this very attractive cast material. The experiment was carried out with 500 7 grade ductile iron, which was austempered using different parameters of heat treatment. The specimens were first solution treated 1 hour in 910oC and then isothermally quenched for different time in silicon oil bath of temperature 275, 325, 300 and 350oC. The mechanical properties heat treated specimens were tested in tensile to evaluate yield stress Re, 0.2, tensile strength Rm and elongation A10. Additionally hardness of heat treated samples was measured using Brinell-Rockwell hardness tester. Structure of the specimens was studied either with conventional metallography, scanning (SEM and transmission (TEM electron microscopy. It followed from the study that conventional grade ductile iron enabled to produce both low and high strength ADI, depend on heat treatment parameters. As expected the low temperature isothermal quenching produced higher strength ADI compare to the same ductile iron but austempered at 350oC. It was discovered however, that low yield strength ADI obtained for short time quenching at 275oC exhibited high strengthening effect while strained in tensile. So it was concluded that this had to by cause by large amount of untransformed austenite, which FCC lattice is characterized by high strengthening coefficient.

  20. 29 CFR 1918.54 - Rigging gear.

    2010-07-01

    ... 29 Labor 7 2010-07-01 2010-07-01 false Rigging gear. 1918.54 Section 1918.54 Labor Regulations...) SAFETY AND HEALTH REGULATIONS FOR LONGSHORING Vessel's Cargo Handling Gear § 1918.54 Rigging gear. (a... other alternate device shall be provided to allow trimming of the gear and to prevent employees...

  1. Development in Geared Turbofan Aeroengine

    Mohd Tobi, A. L.; Ismail, A. E.

    2016-05-01

    This paper looks into the implementation of epicyclic gear system to the aeroengine in order to increase the efficiency of the engine. The improvement made is in the direction of improving fuel consumption, reduction in pollutant gasses and perceived noise. Introduction of epicyclic gear system is capable to achieve bypass ratio of up to 15:1 with the benefits of weight and noise reduction. Radical new aircraft designs and engine installation are being studied to overcome some of the challenges associated with the future geared turbofan and open-rotor engine.

  2. Translation and validation of Autism Diagnostic Interview-Revised (ADI-R for autism diagnosis in Brazil

    Michele M. Becker

    2012-03-01

    Full Text Available OBJECTIVE: To translate into Brazilian Portuguese the Autism Diagnostic Interview-Revised (ADI-R, an extremely useful diagnostic tool in autism. METHODS: A case-control study was done to validate the ADI-R. After being translated, the interview was applied in a sample of 20 patients with autism and 20 patients with intellectual disability without autism, in order to obtain the initial psychometric properties. RESULTS: The internal consistency was high, with a of Crombach of 0.967. The validity of criterion had sensitivity and specificity of 100%, having as a gold standard the DSM-IV diagnostic criteria. The interview had high discriminant validity, with higher scores in the group of patients with autism, as well as high interobserver consistency, with median kappa of 0.824. CONCLUSION: The final version of ADI-R had satisfactory psychometric characteristics, indicating good preliminary validation properties. The instrument needs to be applied in bigger samples in other areas of the country.

  3. Numerical Simulation Of Cutting Of Gear Teeth

    Oswald, Fred B.; Huston, Ronald L.; Mavriplis, Dimitrios

    1994-01-01

    Shapes of gear teeth produced by gear cutters of specified shape simulated computationally, according to approach based on principles of differential geometry. Results of computer simulation displayed as computer graphics and/or used in analyses of design, manufacturing, and performance of gears. Applicable to both standard and non-standard gear-tooth forms. Accelerates and facilitates analysis of alternative designs of gears and cutters. Simulation extended to study generation of surfaces other than gears. Applied to cams, bearings, and surfaces of arbitrary rolling elements as well as to gears. Possible to develop analogous procedures for simulating manufacture of skin surfaces like automobile fenders, airfoils, and ship hulls.

  4. Optimization of compound gear pump

    栾振辉

    2002-01-01

    This paper introduces the performances of compound gear pump. Based on the target of having the smallest mass per unit volume, the paper established a mathematical model of optimization, and obtained the results of optimization of the pump.

  5. Untersuchungen zur Zerspanbarkeit von austenitisch-ferritischem Gusseisen mit Kugelgraphit (ADI)

    Klöpper, Carsten Felix

    2006-01-01

    In many applications increasing demands on weight and cost saving require the application of new materials. In this regard austempered ductile iron (ADI) offers a high potential. Cast iron materials exhibit a high freedom of shape combined with rather low manufacturing costs. In addition, ADI offers an excellent combination of high strength, high toughness and a good wear resistance. The fabrication of ADI-parts consists of a casting process and a following special heat treatment. Depending o...

  6. Theoretical Proof of Unconditional Stability of the 3-D ADI-FDTD Method

    WANG Yingjun; WANG Bingzhong; SHAO Wei

    2003-01-01

    In order to eliminate Courant-Friedrich-Levy(CFL) condition restraint and improve computational efficiency, a new finite-difference time-domain(FDTD) methodbased on the alternatingdirection implicit(ADI) technique is introduced recently. In this paper, a theoretical proof of the stability of the three-dimensional(3-D) ADI-FDTD method is presented. It is shown that the 3-D ADI-FDTD method is unconditionally stable and free from the CFL condition restraint.

  7. Clinical Validity of the ADI-R in a US-Based Latino Population

    Vanegas, Sandra B.; Magaña, Sandra; Morales, Miguel; McNamara, Ellyn

    2016-01-01

    The Autism Diagnostic Interview-Revised (ADI-R) has been validated as a tool to aid in the diagnosis of Autism; however, given the growing diversity in the United States, the ADI-R must be validated for different languages and cultures. This study evaluates the validity of the ADI-R in a US-based Latino, Spanish-speaking population of 50 children…

  8. 50 CFR 660.212 - Fixed gear fishery-prohibitions.

    2010-10-01

    ... vessel subject to subparts C and E a set net, trap or pot, longline, or commercial vertical hook-and-line... by Annex V of the International Convention for the Prevention of Pollution From Ships, 1973 (Annex V... permit with a longline or trap (pot) endorsement and longline and/or trap gear onboard in an...

  9. Effect of alloying elements on austempered ductile iron (ADI properties and its process: Review

    Amir Sadighzadeh Benam

    2015-01-01

    Full Text Available Austempered ductile iron (ADI parts have a unique combination of high strength and toughness with excellent design flexibility and low cost. These excellent properties are directly related to its microstructure called "ausferrite" that is the result of austempering heat treatment applied to ductile irons. Alloying elements increase ADI austemperability and change speeds of austempering reactions. Thus, they can affect ADI resultant microstructure and mechanical properties. In this paper, the effects of alloying elements on ADI mechanical properties, microstructural changes, two-stage austempering reactions, processing windows, austemperability, and other aspects are reviewed.

  10. Intermediate boundary conditions for LOD, ADI and approximate factorization methods

    Leveque, R. J.

    1985-01-01

    A general approach to determining the correct intermediate boundary conditions for dimensional splitting methods is presented. The intermediate solution U is viewed as a second order accurate approximation to a modified equation. Deriving the modified equation and using the relationship between this equation and the original equation allows us to determine the correct boundary conditions for U*. This technique is illustrated by applying it to locally one dimensional (LOD) and alternating direction implicit (ADI) methods for the heat equation in two and three space dimensions. The approximate factorization method is considered in slightly more generality.

  11. Theory of gearing kinematics, geometry, and synthesis

    Radzevich, Stephen P

    2012-01-01

    The first book of its kind, Theory of Gearing: Kinematics, Geometry, and Synthesis systematically develops a scientific theory of gearing that makes it possible to synthesize novel gears with the desired performance. Written by a leading gearing expert who holds more than 200 patents, it presents a modern methodology for gear design. The proposed theory is based on a key postulate: all the design parameters for an optimal gear pair for a particular application can be derived from (a) a given configuration of the rotation vectors of the driving and driven shafts and (b) the power transmitted by

  12. Advanced Face Gear Surface Durability Evaluations

    Lewicki, David G.; Heath, Gregory F.

    2016-01-01

    The surface durability life of helical face gears and isotropic super-finished (ISF) face gears was investigated. Experimental fatigue tests were performed at the NASA Glenn Research Center. Endurance tests were performed on 10 sets of helical face gears in mesh with tapered involute helical pinions, and 10 sets of ISF-enhanced straight face gears in mesh with tapered involute spur pinions. The results were compared to previous tests on straight face gears. The life of the ISF configuration was slightly less than that of previous tests on straight face gears. The life of the ISF configuration was slightly greater than that of the helical configuration.

  13. Advanced theories of hypoid gears

    Wang, Xudong

    2013-01-01

    In order to develop more efficient types of gears, further investigation into the theories of engagement is necessary. Up until now most of the research work on the theories of engagement has been carried out separately on different groups, and based on individual types of profiles. This book aims at developing some universal theories, which can not only be used for all types of gears, but can also be utilized in other fields such as sculptured surfaces. The book has four characteristics: the investigations are concentrated on mismatched tooth surfaces; all the problems are dealt with from a

  14. Development of a gear vibration indicator and its application in gear wear monitoring

    Hu, Chongqing; Smith, Wade A.; Randall, Robert B.; Peng, Zhongxiao

    2016-08-01

    Gear tooth wear is an inevitable phenomenon and has a significant influence on gear dynamic features. Although vibration analysis has been widely used to diagnose localised gear tooth faults, its techniques for gear wear monitoring have not been well-established. This paper aims at developing a vibration indicator to evaluate the effects of wear on gear performance. For this purpose, a gear state vector is extracted from time synchronous averaged gear signals to describe the gear state. This gear state vector consists of the sideband ratios obtained from a number of tooth meshing harmonics and their sidebands. Then, two averaged logarithmic ratios, ALR and mALR, are defined with fixed and moving references, respectively, to provide complementary information for gear wear monitoring. Since a fixed reference is utilised in the definition of ALR, it reflects the cumulated wear effects on the gear state. An increase in the ALR value indicates that the gear state deviates further from its reference condition. With the use of a moving reference, the indicator mALR shows changes in the gear state within short time intervals, making it suitable for wear process monitoring. The efficiency of these vibration indicators is demonstrated using experimental results from two sets of tests, in which the gears experienced different wear processes. In addition to gear wear monitoring, the proposed indicators can be used as general parameters to detect the occurrence of other faults, such as a tooth crack or shaft misalignment, because these faults would also change the gear vibrations.

  15. Numerical investigation of landing gear noise

    Liu, Wen

    2011-01-01

    Noise generated by aircraft landing gears is a major contributor to the overall airframe noise of a commercial aircraft during landing approach. Because of the complex geometry of landing gears, the prediction of landing gear noise has been very difficult and currently relies on empirical tools, which have limited reliability and flexibility on the applications of unconventional gear architectures. The aim of this research is to develop an efficient and accurate numerical method to investigat...

  16. Computer simulation of gear tooth manufacturing processes

    Mavriplis, Dimitri; Huston, Ronald L.

    1990-01-01

    The use of computer graphics to simulate gear tooth manufacturing procedures is discussed. An analytical basis for the simulation is established for spur gears. The simulation itself, however, is developed not only for spur gears, but for straight bevel gears as well. The applications of the developed procedure extend from the development of finite element models of heretofore intractable geometrical forms, to exploring the fabrication of nonstandard tooth forms.

  17. Research on stepless transmission utilizing noncircular gears

    2007-01-01

    In view of the lack of systemic analysis for stepless transmission using noncircular gears, two basic noncircular gear units, an addition unit adopting differential mechanism and a multiplication unit applying a fixed gear train, are proposed. Then, the design methods of the noncircular gear pair of each unit, transmission ratio relationship, rotation angle relationship and key parameters with specific physical meanings are studied. The adjusting properties, composing strategy and varying range of transmiss...

  18. Effect of Si, Mn and Al on the Microstructure and Mechanical Properties of ADI Weld Metal

    2002-01-01

    The effects of Si, Mn and Al on the microstructure and mechanical properties of ADI weld have been studied. The microstructure of ADI weld metal mainly consists of bainitic ferrite and retained austenite. Mechanical properties of ADI weld increase with increasing Si content, but an excess of Si(3.79%) results in decreasing the austemperability owing to decreasing the carbon content of the matrix austenite. Mn increases the retained austenite volume fraction,but the ductility and impact toughness of weld obviously decrease with increasing Mn content because of increased amount of martenite and twin martenite. In the range of 0.13%~0.64%Al, increasing Al content favours improving the mechanical properties of ADI weld. Therefore, it is very important to select suitable Si, Mn and Al contents to improve mechanical properties of ADI weld.

  19. 50 CFR 300.109 - Gear disposal.

    2010-10-01

    ... 50 Wildlife and Fisheries 7 2010-10-01 2010-10-01 false Gear disposal. 300.109 Section 300.109... Antarctic Marine Living Resources § 300.109 Gear disposal. (a) The operator of a harvesting vessel may not... fishing vessels or gear, or that may catch fish or cause damage to any marine resource, including...

  20. 50 CFR 648.203 - Gear restrictions.

    2010-10-01

    ... Herring Fishery § 648.203 Gear restrictions. (a) Midwater trawl gear may only be used by a vessel issued a... 50 Wildlife and Fisheries 8 2010-10-01 2010-10-01 false Gear restrictions. 648.203 Section 648.203 Wildlife and Fisheries FISHERY CONSERVATION AND MANAGEMENT, NATIONAL OCEANIC AND ATMOSPHERIC...

  1. 50 CFR 648.144 - Gear restrictions.

    2010-10-01

    ... Fishery § 648.144 Gear restrictions. (a) Trawl gear restrictions—(1) General. (i) Otter trawlers whose... 50 Wildlife and Fisheries 8 2010-10-01 2010-10-01 false Gear restrictions. 648.144 Section 648.144 Wildlife and Fisheries FISHERY CONSERVATION AND MANAGEMENT, NATIONAL OCEANIC AND ATMOSPHERIC...

  2. 50 CFR 665.664 - Gear restrictions.

    2010-10-01

    ... 50 Wildlife and Fisheries 9 2010-10-01 2010-10-01 false Gear restrictions. 665.664 Section 665.664 Wildlife and Fisheries FISHERY CONSERVATION AND MANAGEMENT, NATIONAL OCEANIC AND ATMOSPHERIC ADMINISTRATION... § 665.664 Gear restrictions. Only selective gear may be used to harvest coral from any precious...

  3. 50 CFR 665.464 - Gear restrictions.

    2010-10-01

    ... 50 Wildlife and Fisheries 9 2010-10-01 2010-10-01 false Gear restrictions. 665.464 Section 665.464 Wildlife and Fisheries FISHERY CONSERVATION AND MANAGEMENT, NATIONAL OCEANIC AND ATMOSPHERIC ADMINISTRATION... Gear restrictions. Only selective gear may be used to harvest coral from any precious coral permit area....

  4. GEAR UP Aspirations Project Evaluation

    Trimble, Brad A.

    2013-01-01

    The purpose of this study was to conduct a formative evaluation of the first two years of the Gaining Early Awareness and Readiness for Undergraduate Programs (GEAR UP) Aspirations Project (Aspirations) using a Context, Input, Process, and Product (CIPP) model so as to gain an in-depth understanding of the project during the middle school…

  5. Dynamic ADI computations of thermoelastic stresses in crystalline laser media

    This article considers thermoelastic effects which influence both the thermal engineering design and optical propagation in solid state high average power laser (HAPL) systems. The methods and computations described here have been developed for applications, ultimately, to crystalline slabs with arbitrary symmetry properties and with arbitrary spatial orientations between crystalline axes and slab configurations. For this, accurate numerical solutions are required simultaneously for the heat equation and Hooke's law in thier most general tensor forms. Prompted by the optical problem requirements in HAPL systems, this work utilizes implementations of Eulerian discretizations and dynamic ADI methods for solving general fourth-order elliptic partial differential equations (PDE's) which describe stress potentials in anisotropic media. These formulations can provide both steady state and transient PDE solutions. This article concludes with computed results for trigonal Al2O3 crystal deformations in various crystal axes/slab orientations

  6. Hainan Gears Up

    ZHANG ZHIPING

    2010-01-01

    @@ Hainan, the southernmost province and the second largest island in China, is well known as a fascinating tropical locale with blue seas basking in beautiful sunshine. At the end of 2009, the island's plan to build it into an international tourist destination was approved by the Central Government. The state is to give greater support and set in place favorable policies for Hainan to fuel its opening up and development.

  7. THE TORQUE METHOD USED FOR STUDYING COUPLED TWO-CARRIER PLANETARY GEAR TRAINS

    Arnaudov, Kiril; Karaivanov, Dimitar

    2013-01-01

    Using the torque method, one can determine not only the speed ratios in complex compound planetary gear trains, but also the magnitude and direction of internal power flows and thus the efficiency. A brief description of the torque method is given in this paper. As an example, a two-carrier compound planetary gear train connected in series was studied. Some more specific and difficult cases of application of this clear and simple method are reviewed a planetary gear train with two degrees of ...

  8. Forced oscillations with time-varying mesh stiffness and backlash in gear systems

    ZHAO Ying; WEN Jian-min; WANG Xiao-ming; LIU Hong; WANG Wei-ling

    2009-01-01

    A dynamic model to describe the torsional vibration behaviors of a spur gear system is presented in this paper. Differential equations of nonlinear dynamics for the gear system exhibiting combined nonlinearity in-fluence such as time-varying mesh stiffness, backlash and dynamic transmission error (DTE) were obtained. The method of multiple scales was employed to solve the nonlinear differential equations with parametric excita-tion in gear systems, by which both the frequency-response curves of the primary resonance caused by internal excitation and the analytical periodic solutions of nonlinear differential equations were obtained. The nonlinear influence of stiffness variation, the damping and the internal excitation on the system response was shown by fre-quency-response curves. Compared with numerical examples, the approximate analytical solutions are in good a-greement with exact solutions, which proves that the method of multiple scales is effective for solving nonlinear problems in gear systems.

  9. Identification of a Non-Linear Landing Gear Model Using Nature-Inspired Optimization

    Felipe A.C. Viana; Valder Steffen Jr.; Marcelo A.X. Zanini; Sandro A. Magalhães; Góes, Luiz C.S.

    2008-01-01

    This work deals with the application of a nature-inspired optimization technique to solve an inverse problem represented by the identification of an aircraft landing gear model. The model is described in terms of the landing gear geometry, internal volumes and areas, shock absorber travel, tire type, and gas and oil characteristics of the shock absorber. The solution to this inverse problem can be obtained by using classical gradient-based optimization methods. However, this is a difficult ta...

  10. Free vibration of planetary gearing

    Půst, Ladislav; Pešek, Luděk; Radolfová, Alena

    Praha : Ústav termomechaniky AV ČR, v. v. i., 2015 - (Zolotarev, I.; Pešek, L.), s. 45-54 ISBN 978-80-87012-57-4. [DYMAMESI 2015. Praha (CZ), 24.11.2015] R&D Projects: GA TA ČR TA04011656 Institutional support: RVO:61388998 Keywords : four-planetary gear ing * free vibrations * input and output devices * torsion model Subject RIV: BI - Acoustics

  11. Lubricants for wind power plants. Gear oils. Requirements and properties; Schmierstoffe fuer Windenergieanlagen. Getriebeoele. Anforderungen und Eigenschaften

    Bock, Wolfgang [Fuchs Europe Schmierstoffe GmbH, Mannheim (Germany)

    2012-11-01

    Alternative energy supply is in the focus and in the discussion world-wide. Electrical energy coming from wind power plants is an important part in the energy supply chain. The lubricants used in wind power plants are often special lubricants, developed for the specific requirements of the application. The range of lubricants included adhesive lubricants, greases, pastes, hydraulic fluids, gear and lubricating oils as well as other specialities. Besides the greases and the hydraulic oils, the gear oil is the most important lubricant in wind power plants. The gear oil is used in the main gear of a wind power plant or in the Azimut gear sets. The lubricant has to be developed to match the requirements of the gear set, the tooth sets, the bearings, the seals, paints, etc. The gear oil has to fulfil the requirements according to DIN 51517, part 3 - CLP / CKC industrial gear oils, and in addition the specific requirements of gear and bearing manufacturers according to wind power plant specifications have to be fulfilled. The presentation ''Lubricants for Wind Power Plants - Requirements and Properties'' gives an overview of the industrial gear oils market, the classification of gear oils according to German and international standards is presented, and it describes the properties of a fully synthetic industrial gear oil based on polyalphaolefin which was especially developed for the main gear unit in wind power plants. The mechanical-dynamic tests for gear oils used in wind power plants (anti-scuffing properties, roller bearing wear protection, micro-pitting protection) are presented, together with the specific tests required by world-wide known bearing manufacturers. In addition the presentation shows test results of low speed wear tests. Compatibility tests with elastomers and sealing materials and the low temperature properties of fully synthetic gear oils based on polyalphaolefin are also discussed. The industrial gear oils for wind power plants

  12. Reduction of belt CVT gear noise by gear train modification. Optimize vibration characteristics of gear train; Belt CVT no gear noise teigen gijutsu. Gear train shindo tokusei no saitekika

    Arimatsu, M.; Kawakami, T. [Nissan Motor Co. Ltd., Tokyo (Japan)

    1997-10-01

    With the reduction of vehicle noise, the requirements for an efficient method to reduce transmission gear noise have become stronger yearly. So far efforts to reduce gear noise have generally focused on ways of improving the gears themselves. In addition to these traditional methods, it proved very beneficial to us to optimize the gear train structure. Nissan has just released the new Belt CVT for 2.0L Front wheel drive vehicles. We have been analyzing vibration of the gear train by using a finite element model since the early development stage, and we could achieve the quiet gears effectively. 2 refs., 9 figs.

  13. Dudley's handbook of practical gear design and manufacture

    Radzevich, Stephen P

    2012-01-01

    A unique, single source reference for all aspects of gears, Dudley's Handbook of Practical Gear Design and Manufacture, Second Edition provides comprehensive and consistent information on the design and manufacture of gears for the expert and novice alike. The second edition of this industry standard boasts seven new chapters and appendices as well as a wealth of updates throughout. New chapters and expanded topics include: Gear Types and Nomenclature, Gear Tooth Design, Gear Reactions and Mountings, Gear Vibration, The Evolution of the Gear Art, Novikov Gearing and the Inadequacy of the Term,

  14. 29 CFR 1919.19 - Gear requiring welding.

    2010-07-01

    ... 29 Labor 7 2010-07-01 2010-07-01 false Gear requiring welding. 1919.19 Section 1919.19 Labor... (CONTINUED) GEAR CERTIFICATION Certification of Vessels' Cargo Gear § 1919.19 Gear requiring welding. Chains or other gear which have been lengthened, altered or repaired by welding shall be properly...

  15. Gear failure of a PHWR refuelling machine

    After ten year service in Atucha Nuclear Station a gear belonging to a pressurized heavy water reactor refuelling machine, failed. The gear box was used to transmit motion to the inlet-outlet heavy-water valve of that machine. Visual examination of the gear device revealed an absence of lubricant and several gear teeth were broken off at the root. The gear motion was transmitted from a speed-reducing device with controlled adjustable times in order to produce a right fitness of the valve closure. The main cause of gear failure was due to misalignment produced during assembly or in-service operation. It is suggested to control periodically the level of oil lubricant. (orig./IHOE)

  16. Magnetorheological landing gear: 1. A design methodology

    Batterbee, D.C.; N.D. Sims; STANWAY, R.; Wolejsza, Zbigniew

    2007-01-01

    Aircraft landing gears are subjected to a wide range of excitation conditions, which result in conflicting damping requirements. A novel solution to this problem is to implement semi-active damping using magnetorheological (MR) fluids. This paper presents a design methodology that enables an MR landing gear to be optimized, both in terms of its damping and magnetic circuit performance, whilst adhering to stringent packaging constraints. Such constraints are vital in landing gear, if MR techno...

  17. Tool Gear: Infrastructure for Parallel Tools

    May, J; Gyllenhaal, J

    2003-04-17

    Tool Gear is a software infrastructure for developing performance analysis and other tools. Unlike existing integrated toolkits, which focus on providing a suite of capabilities, Tool Gear is designed to help tool developers create new tools quickly. It combines dynamic instrumentation capabilities with an efficient database and a sophisticated and extensible graphical user interface. This paper describes the design of Tool Gear and presents examples of tools that have been built with it.

  18. An arithmetic for core physics real-time simulation based on ADI

    Alternative Direction Implicit (ADI) method is a traditional approach to solve diffusion problems. But it's not a good method for solving neutron diffusion equations in real-time simulation. To conquer this, an improved ADI method is introduced in this paper. Its accuracy is tested by its application to the core physics real-time simulation for Qinshan NPP. With online correction technology, this method can be used in the core physics real-time simulation for the reactor whole life stage. (authors)

  19. Study on ADI CD bias correlating ABC function

    Deng, Guogui; Hao, Jingan; Xing, Bin; Jiang, Yuntao; Li, Gaorong; Zhang, Qiang; Yue, Liwan; Zu, Yanlei; Hu, Huayong; Liu, Chang; Shen, Manhua; Zhang, Shijian; He, Weiming; Zhang, Nannan; Lin, Yi-Shih; Wu, Qiang; Shi, Xuelong

    2015-03-01

    As the technology node of semiconductor industry is being driven into more advanced 28 nm and beyond, the critical dimension (CD) error budget at after-development inspection (ADI) stage and its control are more and more important and difficult (1-4). 1 nm or even 0.5 nm CD difference is critical for process control. 0.5~1 nm drift of poly linewidth will result in a detectable off-target drift of device performance. The 0.5~1 nm CD drift of hole or metal linewidth on the backend interconnecting layers can potentially contribute to the bridging of metal patterns to vias, and thereby impact yield. In this paper, we studied one function in the scanning electron microscope (SEM) measurement, i.e. the adjustment of brightness and contrast (ABC). We revealed how the step of addressing focus and even the choice of addressing pattern may bring in a systematic error into the CD measurement. This provides a unique insight in the CD measurement and the measurement consistency of through-pitch (TP) patterns and functional patterns.

  20. Effects of gear crack propagation paths on vibration responses of the perforated gear system

    Ma, Hui; Pang, Xu; Zeng, Jin; Wang, Qibin; Wen, Bangchun

    2015-10-01

    This paper investigates the dynamic behaviors of a perforated gear system considering effects of the gear crack propagation paths and this study focuses on the effects of a crack propagating through the rim on the time-varying mesh stiffness (TVMS) and vibration responses. Considering the effects of the extended tooth contact, a finite element (FE) model of a gear pair is established based on ANSYS software. TVMS of the perforated gear with crack propagating through tooth and rim are calculated by using the FE model. Furthermore, a lumped mass model is adopted to investigate the vibration responses of the perforated gear system. The results show that there exist three periods related to slots of the gear body in a rotating period of the perforated gear. Gear cracks propagating through tooth and rim both reduce the gear body stiffness and lead to reduction of TVMS besides the crack tooth contact moment, and the TVMS weakening for the former is less than that for the latter. Moreover, the results also show that the gear crack propagating through the rim (CPR) has a greater effect on vibration responses than the gear crack propagating through the tooth (CPT) under the same crack level. Vibration level increases with the increasing crack depth, especially for the gear with CPR.

  1. 50 CFR 648.84 - Gear-marking requirements and gear restrictions.

    2010-10-01

    ... 50 Wildlife and Fisheries 8 2010-10-01 2010-10-01 false Gear-marking requirements and gear restrictions. 648.84 Section 648.84 Wildlife and Fisheries FISHERY CONSERVATION AND MANAGEMENT, NATIONAL... Management Measures for the NE Multispecies and Monkfish Fisheries § 648.84 Gear-marking requirements...

  2. Comparative toxicokinetics of low-viscosity mineral oil in Fischer 344 rats, Sprague-Dawley rats, and humans--implications for an Acceptable Daily Intake (ADI).

    Boogaard, Peter J; Goyak, Katy O; Biles, Robert W; van Stee, Leo L P; Miller, Matthew S; Miller, Mary Jo

    2012-06-01

    Oral repeated-dose studies with low-viscosity mineral oils showed distinct species and strain differences, which are hypothesized to be due to differences in bioavailability, with Fischer 344 rats being more susceptible than Sprague-Dawley rats or dogs. Sensitive analytical methodology was developed for accurate measurement of low levels of mineral hydrocarbons and applied in single-dose toxicokinetics studies in rats and humans. Fischer 344 rats showed a 4-fold higher AUC(0-∞) and consistently higher blood and liver concentrations were found than Sprague-Dawley rats. Hepatic mineral hydrocarbon concentration tracked the blood concentration in both strains, indicating that blood concentrations can serve as functional surrogate measure for hepatic concentrations. In human volunteers receiving 1mg/kg body weight of low-viscosity white oil, all blood concentrations of mineral hydrocarbons were below the detection limit. Comparison with threshold blood concentrations associated with NOAELs in both rat strains, indicate that the margin-of-exposure is at least 37-fold. Using an internal dose metric rather than applied dose reduces the uncertainty around the temporary ADI considerably since it intrinsically accounts for intra- and inter-species differences. The current data support replacement of the temporary ADI of 0.01 mg/kg/day by a (permanent) ADI of at least 1.0mg/kg/day for low- and medium-viscosity mineral oils. PMID:22425899

  3. Optimum weight design of functionally graded material gears

    Jing, Shikai; Zhang, He; Zhou, Jingtao; Song, Guohua

    2015-11-01

    Traditional gear weight optimization methods consider gear tooth number, module, face width or other dimension parameters of gear as design variables. However, due to the complicated form and geometric features peculiar to the gear, there will be large amounts of design parameters in gear design, and the influences of gear parameters changing on gear trains, transmission system and the whole equipment have to be taken into account, which increases the complexity of optimization problem. This paper puts forward to apply functionally graded materials (FGMs) to gears and then conduct the optimization. According to the force situation of gears, the material distribution form of FGM gears is determined. Then based on the performance parameters analysis of FGMs and the practical working demands for gears, a multi-objective optimization model is formed. Finally by using the goal driven optimization (GDO) method, the optimal material distribution is achieved, which makes gear weight and the maximum deformation be minimum and the maximum bending stress do not exceed the allowable stress. As an example, the applying of FGM to automotive transmission gear is conducted to illustrate the optimization design process and the result shows that under the condition of keeping the normal working performance of gear, the method achieves in greatly reducing the gear weight. This research proposes a FGM gears design method that is able to largely reduce the weight of gears by optimizing the microscopic material parameters instead of changing the macroscopic dimension parameters of gears, which reduces the complexity of gear weight optimization problem.

  4. Dynamic Analysis of Wind Turbine Planetary Gears Using an Extended Harmonic Balance Approach: Preprint

    Guo, Y.; Keller, J.; Parker, R. G.

    2012-06-01

    The dynamics of wind turbine planetary gears with gravity effects are investigated using an extended harmonic balance method that extends established harmonic balance formulations to include simultaneous internal and external excitations. The extended harmonic balance method with arc-length continuation and Floquet theory is applied to a lumped-parameter planetary gear model including gravity, fluctuating mesh stiffness, bearing clearance, and nonlinear tooth contact to obtain the planetary gear dynamic response. The calculated responses compare well with time domain integrated mathematical models and experimental results. Gravity is a fundamental vibration source in wind turbine planetary gears and plays an important role in system dynamics, causing hardening effects induced by tooth wedging and bearing-raceway contacts. Bearing clearance significantly reduces the lowest resonant frequencies of translational modes. Gravity and bearing clearance together lowers the speed at which tooth wedging occurs lower than the resonant frequency.

  5. CNC FLEXIBLE GENERATING SPECIFIC GEAR TOOTH PROFILE BASED ON STANDARD INVOLUTE GEAR HOB

    Feng Xianying; Li Hui; Ai Xing

    2004-01-01

    A new method named orthogonal two-way link-shift here has been proposed. Based on the method and a standard involute gear hob, a specific gear tooth profile (including an arbitrary gear tooth profile and a modified involute gear tooth profile) can be generated on a CNC(computer numerical control) hobbing machine. Computer simulation has been carried out, and the results prove that the method is right and practicable. So, the fabrication costs can be greatly decreased than before. The new method has momentous significance to realize gear's optimized modification under different work conditions.

  6. Dynamic Modeling and Chaotic Analysis of Gear Transmission System in a Braiding Machine with or without Random Perturbation

    Zhang Yujing

    2016-01-01

    Full Text Available This paper is aimed at analyzing the dynamic behavior of the gear transmission system in a braiding machine. In order to observe the nonlinear phenomenon and reveal the time-varying gear meshing mechanism, a mathematical model with five degrees-of-freedom gear system under internal and external random disturbance of gear system is established. With this model, bifurcation diagrams, Poincare maps, phase diagrams, power spectrum, time-process diagrams, and Lyapunov exponents are used to identify the chaotic status. Meanwhile, by these analytical methods, spur gear pair with or without random perturbation are compared. The numerical results suggest that the vibration behavior of the model is consistent with that of Clifford system. The chaotic system associated parameters are picked out, which can be helpful to the design and control of braiding machines.

  7. Computer aided design of spur gear teeth

    Huston, R. L.; Mavriplis, D.; Oswald, F. B.

    1989-01-01

    Procedures for computer-modeling of spur gear tooth fabrication are given. It is shown that the standard involute tooth form results from a cutter with an involute shape rolling onto a gear blank. Specifically, the envelope of an involute is an involute. Examples are given and applications are discussed.

  8. 50 CFR 665.128 - Gear identification.

    2010-10-01

    ... 50 Wildlife and Fisheries 9 2010-10-01 2010-10-01 false Gear identification. 665.128 Section 665.128 Wildlife and Fisheries FISHERY CONSERVATION AND MANAGEMENT, NATIONAL OCEANIC AND ATMOSPHERIC... § 665.128 Gear identification. (a) The vessel number must be affixed to all fish and crab traps on...

  9. 50 CFR 660.506 - Gear restrictions.

    2010-10-01

    ... restrictions. The only fishing gear authorized for use in the reduction fishery for northern anchovy off... 50 Wildlife and Fisheries 9 2010-10-01 2010-10-01 false Gear restrictions. 660.506 Section 660.506 Wildlife and Fisheries FISHERY CONSERVATION AND MANAGEMENT, NATIONAL OCEANIC AND ATMOSPHERIC...

  10. 50 CFR 648.163 - Gear restrictions.

    2010-10-01

    ... Bluefish Fishery § 648.163 Gear restrictions. If the Council determines through its annual review or... 50 Wildlife and Fisheries 8 2010-10-01 2010-10-01 false Gear restrictions. 648.163 Section 648.163 Wildlife and Fisheries FISHERY CONSERVATION AND MANAGEMENT, NATIONAL OCEANIC AND ATMOSPHERIC...

  11. 50 CFR 665.246 - Gear identification.

    2010-10-01

    ... 50 Wildlife and Fisheries 9 2010-10-01 2010-10-01 false Gear identification. 665.246 Section 665.246 Wildlife and Fisheries FISHERY CONSERVATION AND MANAGEMENT, NATIONAL OCEANIC AND ATMOSPHERIC... Gear identification. In Permit Area 1, the vessel's official number must be marked legibly on all...

  12. 50 CFR 665.228 - Gear identification.

    2010-10-01

    ... 50 Wildlife and Fisheries 9 2010-10-01 2010-10-01 false Gear identification. 665.228 Section 665.228 Wildlife and Fisheries FISHERY CONSERVATION AND MANAGEMENT, NATIONAL OCEANIC AND ATMOSPHERIC... Gear identification. (a) The vessel number must be affixed to all fish and crab traps on board...

  13. 50 CFR 665.428 - Gear identification.

    2010-10-01

    ... 50 Wildlife and Fisheries 9 2010-10-01 2010-10-01 false Gear identification. 665.428 Section 665.428 Wildlife and Fisheries FISHERY CONSERVATION AND MANAGEMENT, NATIONAL OCEANIC AND ATMOSPHERIC... § 665.428 Gear identification. (a) The vessel number must be affixed to all fish and crab traps on...

  14. 50 CFR 679.24 - Gear limitations.

    2010-10-01

    ..., hooks are removed without jeopardizing the life of the birds. (3) Seabird avoidance gear requirements.... long. 55°00′ N. lat., 167°00′ W. long. (e) Seabird avoidance program for vessels fishing with hook-and... with hook-and-line gear must comply with the seabird avoidance requirements as specified in...

  15. The Dilemma of Derelict Gear.

    Scheld, A M; Bilkovic, D M; Havens, K J

    2016-01-01

    Every year, millions of pots and traps are lost in crustacean fisheries around the world. Derelict fishing gear has been found to produce several harmful environmental and ecological effects, however socioeconomic consequences have been investigated less frequently. We analyze the economic effects of a substantial derelict pot removal program in the largest estuary of the United States, the Chesapeake Bay. By combining spatially resolved data on derelict pot removals with commercial blue crab (Callinectes sapidus) harvests and effort, we show that removing 34,408 derelict pots led to significant gains in gear efficiency and an additional 13,504 MT in harvest valued at US $21.3 million--a 27% increase above that which would have occurred without removals. Model results are extended to a global analysis where it is seen that US $831 million in landings could be recovered annually by removing less than 10% of the derelict pots and traps from major crustacean fisheries. An unfortunate common pool externality, the degradation of marine environments is detrimental not only to marine organisms and biota, but also to those individuals and communities whose livelihoods and culture depend on profitable and sustainable marine resource use. PMID:26790394

  16. Methods for detecting fatigue cracks in gears

    A crack in the tooth root is the least desirable damage caused to gear units and it often causes failure of gear unit operation. For fault analyses presented in this article, gear units with real damages or faults produced on the basis of numerical simulations of real operating conditions are used; tests were carried out in a laboratory test plant. Damages in gear units can be identified by monitoring vibrations. The influences of a crack in a single-stage gear unit on produced vibrations are presented. Significant changes in tooth stiffness are caused by a fatigue crack in the tooth root whereas, in relation to other faults, changes of other dynamic parameters are more expressed. Non-stationary signals are analysed, using the family of Time Frequency Analysis tools, which include Wavelets and Joint Time Frequency Analyses.

  17. Polyamide worm gear: manufacturing and performance

    Alexandre Luís Gasparin

    2012-06-01

    Full Text Available The focus of this paper is to establish a characterisation method for seven polyamide (PA grades to determine the major material to manufacture an automotive worm gear. The composite properties were measured according to the worm gear loadings: tensile strength, Young's modulus, abrasion and impact resistance. They were also correlated to the PA moisture absorption and its glass fibre (GF reinforcement. The data from mechanical tests were applied in the finite element analysis (FEA using the von Mises stress criterion. Before the rig tests of the PA worm gears, the injection process was evaluated, through the capillary rheometry. A higher difficulty to process PA 6/6 30% GF was found, due to its lower apparent viscosity. In the end, the influence of moisture absorption was as decisive to the gear's material selection as the GF to the pinion. Thus, the PAs with the best performance were: PA 6 with 30% GF (gear and with PA 60% GF (pinion.

  18. Torsional Vibration of Machines with Gear Errors

    Vibration and noise induced by errors and faults in gear meshes are key concerns for the performance of many rotating machines and the prediction of developing faults. Of particular concern are displacement errors in the gear mesh and for rigid gears these may be modelled to give a linear set of differential equations with forced excitation. Other faults, such as backlash or friction, may also arise and give non-linear models with rich dynamics. This paper considers the particular case of gear errors modelled as a Fourier series based on the tooth meshing frequency, leading immediately to non-linear equations of motion, even without the presence of other non-linear phenomena. By considering the perturbed response this system may be modelled as a parametrically excited system. This paper motivates the analysis, derives the equations of motion for the case of a single gear mesh, and provides example response simulations of a boiler feed pump including phase portraits and power spectra.

  19. Analysis of Landing-Gear Behavior

    Milwitzky, Benjamin; Cook, Francis E

    1953-01-01

    This report presents a theoretical study of the behavior of the conventional type of oleo-pneumatic landing gear during the process of landing impact. The basic analysis is presented in a general form and treats the motions of the landing gear prior to and subsequent to the beginning of shock-strut deflection. The applicability of the analysis to actual landing gears has been investigated for the particular case of a vertical landing gear in the absence of drag loads by comparing calculated results with experimental drop-test data for impacts with and without tire bottoming. The calculated behavior of the landing gear was found to be in good agreement with the drop-test data.

  20. Testing of heating and cooling process of ADI cast iron with use of ATND method

    A. Białobrzeski

    2008-10-01

    Full Text Available ADI (Austempered Ductile Iron cast iron, owing to its unique combination of high tensile strength and abrasion resistance with very goodplasticity, founds implementation in many branches of industry as a substitute of alloy cast steel and carburized or heat treated steels. Inspite of its solid position among producers and recipients of castings, there are still undertaken studies aimed at perfection of its propertiesand recognition of mechanisms enabling obtaining such properties.The paper presents implementation of thermal-voltage-derivative (ATND method to registration of heating and cooling course of ADIcast iron with EN-GJS-1200-2 grade. ADI cast iron with EN-GJS-1200-2 grade underwent the study. Heat treatment of the cast iron wasperformed in Foundry Institute with use of LT ADI-350/1000 processing line. Results obtained from the testing illustrate in graphic formregistered heating and cooling curves of investigated cast irons obtained with use of the ATND method.

  1. Možnosti programování mikrořadičů

    Šubrt, Stanislav

    2011-01-01

    Tato práce se zabývá vnitřní strukturou a možnostmi programování mikrořadičů. Cílem práce je popsat vnitřní strukturu mikrořadičů z pohledu programátora, zhodnotit výhody a nevýhody jejich programování v jazyce symbolických adres, jazyce C a nástrojích vyšší úrovně. Dále se práce zabývá přenositelností kódu mezi různými rodinami a architekturami mikrořadičů.

  2. GENETIC ALGORITHM IN REDUCTION OF NUMERICAL DISPERSION OF 3-D ADI-FDTD METHOD

    Zhang Yan; Lǖ Shanwei; Gao Wenjun

    2007-01-01

    A new method to reduce the numerical dispersion of the three-dimensional Alternating Direction Implicit Finite-Difference Time-Domain(3-D ADI-FDTD)method is proposed.Firstly,the numerical formulations of the 3-D ADI-FDTD method are modified with the artificial anisotropy,and the new numerical dispersion relation is derived.Secondly,the relative permittivity tensor of the artificial anisotropy can be obtained by the Adaptive Genetic Algorithm(AGA).In order to demonstrate the accuracy and efficiency of this new method,a monopole antenna is simulated as an example.And the numerical results and the computational requirements of the proposed method are cornpared with those of the conventional ADI-FDTD method and the measured data.In addition the reduction of the numerical dispersion is investigated as the objective function of the AGA.It is found that this new method is accurate and efficient by choosing proper objective function.

  3. 14 CFR 25.1515 - Landing gear speeds.

    2010-01-01

    ... 14 Aeronautics and Space 1 2010-01-01 2010-01-01 false Landing gear speeds. 25.1515 Section 25... Limitations § 25.1515 Landing gear speeds. (a) The established landing gear operating speed or speeds, V LO, may not exceed the speed at which it is safe both to extend and to retract the landing gear,...

  4. 14 CFR 23.477 - Landing gear arrangement.

    2010-01-01

    ... 14 Aeronautics and Space 1 2010-01-01 2010-01-01 false Landing gear arrangement. 23.477 Section 23....477 Landing gear arrangement. Sections 23.479 through 23.483, or the conditions in appendix C, apply to airplanes with conventional arrangements of main and nose gear, or main and tail gear....

  5. 29 CFR 1919.31 - Proof tests-loose gear.

    2010-07-01

    ... 29 Labor 7 2010-07-01 2010-07-01 false Proof tests-loose gear. 1919.31 Section 1919.31 Labor... (CONTINUED) GEAR CERTIFICATION Certification of Vessels: Tests and Proof Loads; Heat Treatment; Competent Persons § 1919.31 Proof tests—loose gear. (a) Chains, rings, shackles and other loose gear...

  6. 46 CFR 108.641 - Instructions for changing steering gear.

    2010-10-01

    ... 46 Shipping 4 2010-10-01 2010-10-01 false Instructions for changing steering gear. 108.641 Section... steering gear. Instructions stating, in order, the different steps to be taken for changing to emergency and secondary steering gear must be posted in the steering gear room and at each secondary...

  7. 46 CFR 58.25-20 - Piping for steering gear.

    2010-10-01

    ... 46 Shipping 2 2010-10-01 2010-10-01 false Piping for steering gear. 58.25-20 Section 58.25-20... MACHINERY AND RELATED SYSTEMS Steering Gear § 58.25-20 Piping for steering gear. (a) Pressure piping must... the hydraulic system can be readily recharged from within the steering-gear compartment and must...

  8. 49 CFR 230.77 - Foundation brake gear.

    2010-10-01

    ... 49 Transportation 4 2010-10-01 2010-10-01 false Foundation brake gear. 230.77 Section 230.77... Tenders Brake and Signal Equipment § 230.77 Foundation brake gear. (a) Maintenance. Foundation brake gear...) Distance above the rails. No part of the foundation brake gear of the steam locomotive or tender shall...

  9. 50 CFR 660.211 - Fixed gear fishery-definitions.

    2010-10-01

    ... 50 Wildlife and Fisheries 9 2010-10-01 2010-10-01 false Fixed gear fishery-definitions. 660.211... Groundfish-Limited Entry Fixed Gear Fisheries § 660.211 Fixed gear fishery—definitions. These definitions are... weekly and/or bimonthly trip limits. Limited entry fixed gear fishery means the fishery composed...

  10. 50 CFR 622.46 - Prevention of gear conflicts.

    2010-10-01

    ... 50 Wildlife and Fisheries 8 2010-10-01 2010-10-01 false Prevention of gear conflicts. 622.46... Management Measures § 622.46 Prevention of gear conflicts. (a) No person may knowingly place in the Gulf EEZ... zones for shrimp trawling and the use of fixed gear to prevent gear conflicts. Necessary prohibitions...

  11. Low-Noise Spiral Bevel Gears

    Lewicki, David G.; Handschuh, Robert F.; Coy, John J.; Henry, Zachary; Thomas, John; Litvin, Faydor L.

    1994-01-01

    Modified spiral bevel gears that generate relatively little noise and vibration designed and fabricated for use in U.S. Army OH-58D helicopter. Noise reduced by 12 to 19 dB. Similar low-noise, low-vibration spiral bevel gears used in other helicopters, with consequent benefits in comfort and health of pilots and passengers, enhancement of pilots' performance and safety through reduction of audible distraction, and reduction in cost and weight of helicopters through reduction in amount of sound-proofing material. Low-noise, low-vibration spiral bevel gears also used in drive axles of cars and trucks for smoother, quieter rides.

  12. NASA Orbiter Extended Nose Landing Gear

    King, Steven R.; Jensen, Scott A.; Hansen, Christopher P.

    1999-01-01

    This paper discusses the design, development, test, and evaluation of a prototype Extended Nose Landing Gear (ENLG) for NASA's Space Shuttle orbiters. The ENLG is a proposed orbiter modification developed in-house at NASA's Johnson Space Center (JSC) by a joint government/industry team. It increases the orbiter's nose landing gear (NLG) length, thereby changing the vehicle's angle of attack during rollout, which lowers the aerodynamic forces on the vehicle. This, in combination with a dynamic elevon change, will lower the loads on the orbiter's main landing gear (MLG). The extension is accomplished by adding a telescoping section to the current NLG strut that will be pneumatically extended during NLG deployment.

  13. MODERNIZATION OF TRACKED VEHICLE RUNNING GEARS

    V. Tamelo

    2013-01-01

    Full Text Available The paper contains some proposals pertaining  to modernization of tracked vehicle running gears, bogie hydro-pneumatic suspension, methodology  for bench-tests and description of test-bench equipment which is applied for testing bogie hydro-pneumatic suspension. Test results of a hydro-pneumatic spring with parameter stabilization system are given in the paper.The paper presents  description of tracked vehicle running gears with bogie hydro-pneumatic suspension which is equipped with a system for stabilizing a road clearance. Testing results of the gears being part of a test mule are cited in the paper.

  14. Engagement of Metal Debris into Gear Mesh

    handschuh, Robert F.; Krantz, Timothy L.

    2010-01-01

    A series of bench-top experiments was conducted to determine the effects of metallic debris being dragged through meshing gear teeth. A test rig that is typically used to conduct contact fatigue experiments was used for these tests. Several sizes of drill material, shim stock and pieces of gear teeth were introduced and then driven through the meshing region. The level of torque required to drive the "chip" through the gear mesh was measured. From the data gathered, chip size sufficient to jam the mechanism can be determined.

  15. High Speed Gear Sized and Configured to Reduce Windage Loss

    Kunz, Robert F. (Inventor); Medvitz, Richard B. (Inventor); Hill, Matthew John (Inventor)

    2013-01-01

    A gear and drive system utilizing the gear include teeth. Each of the teeth has a first side and a second side opposite the first side that extends from a body of the gear. For each tooth of the gear, a first extended portion is attached to the first side of the tooth to divert flow of fluid adjacent to the body of the gear to reduce windage losses that occur when the gear rotates. The gear may be utilized in drive systems that may have high rotational speeds, such as speeds where the tip velocities are greater than or equal to about 68 m/s. Some embodiments of the gear may also utilize teeth that also have second extended portions attached to the second sides of the teeth to divert flow of fluid adjacent to the body of the gear to reduce windage losses that occur when the gear rotates.

  16. On the possibility of replacing high manganese cast steel military vehicle track pads with ADI

    M. Kaczorowski

    2010-01-01

    Full Text Available The theoretical considerations of possibility replacing of high manganese cast steel used for military vehicle track pads with ADI are presented. Except these considerations, comparative investigations including tensile strength tests hardness measurements and impact resistance were included. Moreover, the structure investigation was carried out using either conventional light metallography and scanning (SEM. The last one was applied for fractography investigations, the aim of which was to discover the mode of fracture. The discussion of experimental results leads to conclusion that ADI, known as high friction resistant, looks to be concurrent material with respect to high manganese cast steel used now for tang track pads.

  17. OSOBITOSTI STIJENKE MOKRAĆNOG MJEHURA U DOJENČADI DO 6 MJESECI ŽIVOTA

    Saraga, Marijan; Drnasin, Kristina; Čapkun, Vesna

    2007-01-01

    Cilj: Odrediti ultrazvukom normalne vrijednosti debljine stijenke mokraćnog mjehura zdrave dojenčadi u prvih 6 mjeseci života i utvrditi postoje li razlike s obzirom na spol. Ispitanici i metode: Obavljen je ultrazvučni probir mokraćnog mjehura 416-ero zdrave donošene dojenčadi (216 muške i 200 ženske) u dobi od 0,5 do 6 mjeseci života. Debljine stijenke mokraćnog mjehura analizirane su ultrazvučnim aparatom Siemens Sonoline Prima, semikonveksnom sondom od 5,0 MHz i linearnom sondom od 7,5 MH...

  18. Influence of gear loss factor on the power loss prediction

    C. M. C. G. Fernandes; P. M. T. Marques; R. C. Martins; J. H. O. Seabra

    2015-01-01

    In order to accurately predict the power loss generated by a meshing gear pair the gear loss factor must be properly evaluated. Several gear loss factor formulations were compared, including the author's approach. A gear loss factor calculated considering the load distribution along the path of contact was implemented. The importance of the gear loss factor in the power loss predictions was put in evidence comparing the predictions with experimental results. It was ...

  19. Empirical Prediction of Aircraft Landing Gear Noise

    Golub, Robert A. (Technical Monitor); Guo, Yue-Ping

    2005-01-01

    This report documents a semi-empirical/semi-analytical method for landing gear noise prediction. The method is based on scaling laws of the theory of aerodynamic noise generation and correlation of these scaling laws with current available test data. The former gives the method a sound theoretical foundation and the latter quantitatively determines the relations between the parameters of the landing gear assembly and the far field noise, enabling practical predictions of aircraft landing gear noise, both for parametric trends and for absolute noise levels. The prediction model is validated by wind tunnel test data for an isolated Boeing 737 landing gear and by flight data for the Boeing 777 airplane. In both cases, the predictions agree well with data, both in parametric trends and in absolute noise levels.

  20. Sea Turtle Human/Gear Interactions Data

    National Oceanic and Atmospheric Administration, Department of Commerce — The Southeast Fisheries Science Center Mississippi Laboratories is responsible for new gear development and testing to reduce bycatch and incidental interactions of...

  1. Vibration Based Sun Gear Damage Detection

    Hood, Adrian; LaBerge, Kelsen; Lewicki, David; Pines, Darryll

    2013-01-01

    Seeded fault experiments were conducted on the planetary stage of an OH-58C helicopter transmission. Two vibration based methods are discussed that isolate the dynamics of the sun gear from that of the planet gears, bearings, input spiral bevel stage, and other components in and around the gearbox. Three damaged sun gears: two spalled and one cracked, serve as the focus of this current work. A non-sequential vibration separation algorithm was developed and the resulting signals analyzed. The second method uses only the time synchronously averaged data but takes advantage of the signal/source mapping required for vibration separation. Both algorithms were successful in identifying the spall damage. Sun gear damage was confirmed by the presence of sun mesh groups. The sun tooth crack condition was inconclusive.

  2. 基于ADIS16365的惯性传感系统设计%Design of Inertial Sensing System Based on ADIS16365

    邓德源; 蔺震; 高林

    2011-01-01

    系统以ADIS16365为惯性传感器,LM3S8962为核心处理器,IAR为开发平台,卡尔曼滤波和辛普森积分为数据处理方法,研制基于ADIS16365的惯性传感系统.结果表明,该系统具有较高的角度稳定性和准确性.为了使该系统具有应用的灵活性,将该传感系统作为CAN节点应用在整个系统设计中.该系统已用于亚太机器人比赛中,实现了准确定位.%An inertial sensing system was designed by taking ADIS16365 as inertial senser, LM3S8962 as kernel processor, IAR as development platform, Kalman filter and Simpson integration as data processing methods. The results of static and dynamic tests show that the system has high stability and high accuracy. The sensing system is used as a CAN node in the design of a whole equipment to make the equipment more flexible. The inertial sensing system was successfully used in ABU Robocon Contest and implemented the accurate location.

  3. Perforated fairings for landing gear noise control

    Boorsma, K.; Zhang, X; Molin, N.

    2008-01-01

    Landing gears of commercial aircraft make an important contribution to total aircraft noise in the approach configuration. Using fairings to shield components from high speed impingement reduces noise. Furthermore, perforating these fairings has been confirmed by flight tests to further enable noise reduction. Following a more fundamental study on the application of perforated fairings, a study has been performed to investigate and optimize the benefits of bleeding air through landing gear fa...

  4. More Electric Landing Gear Actuation Study

    Li, Wei

    2009-01-01

    This report addresses the problem of landing gear actuation system design on more-electric aircraft (MEA). Firstly, information about more-electric aircraft and more-electric actuators was gathered and sorted. Current more-electric landing actuation system applications and researches were also summarized. Then several possible more-electric landing gear actuation concepts were identified. To evaluate these concepts, the case study method has been used. A concept aircraft “MR...

  5. Vibration Control of MR Damper Landing Gear

    Disha Saxena; Harsh Rathore

    2013-01-01

    In the field of Automation, Fuzzy Control Fuzzy control has significant merits which are utilized in intelligent controllers, especially for vibration control systems. This paper is concerned with the application aspects of the developed MR damper for landing gear system, to attenuate the sustained vibrations during the landing phase. Also a comparative study is made on the responses obtained from the MR damper landing gear by utilizing PID and Fuzzy PID controllers.Theory is a well-known tec...

  6. Computational aeroacoustic study of a landing gear

    Khanal, B.; Knowles, K.; Saddington, Alistair J.; Obayashi, S

    2009-01-01

    Computational study of a single wheel landing gear con guration was completed to understand the noise source and it's nature. The ow eld visualisation showed the present of large structural shedding in the wake side of the the landing gear wheel. These large structures were responsible for the low frequency noise. Spectral peaks at frequencies lower than 200 Hz were found to exist from the analysis of the frequency content of the pressure signals at far eld. These low freque...

  7. Polyamide worm gear: manufacturing and performance

    Alexandre Luís Gasparin; Leandro Luís Corso; Eduardo Kirinus Tentardini; Regina Célia Reis Nunes; Maria Madalena Camargo Forte; Ricardo Vinicius Bof de Oliveira

    2012-01-01

    The focus of this paper is to establish a characterisation method for seven polyamide (PA) grades to determine the major material to manufacture an automotive worm gear. The composite properties were measured according to the worm gear loadings: tensile strength, Young's modulus, abrasion and impact resistance. They were also correlated to the PA moisture absorption and its glass fibre (GF) reinforcement. The data from mechanical tests were applied in the finite element analysis (FEA) using t...

  8. Instrumentation and test gear circuits manual

    Marston, R M

    2013-01-01

    Instrumentation and Test Gear Circuits Manual provides diagrams, graphs, tables, and discussions of several types of practical circuits. The practical circuits covered in this book include attenuators, bridges, scope trace doublers, timebases, and digital frequency meters. Chapter 1 discusses the basic instrumentation and test gear principles. Chapter 2 deals with the design of passive attenuators, and Chapter 3 with passive and active filter circuits. The subsequent chapters tackle 'bridge' circuits, analogue and digital metering techniques and circuitry, signal and waveform generation, and p

  9. X-38 Landing Gear Skid Test Report

    Gafka, George K.; Daugherty, Robert H.

    2000-01-01

    NASA incorporates skid-equipped landing gear on its series of X-38 flight test vehicles. The X-38 test program is the proving ground for the Crew Return Vehicle (CRV) a gliding parafoil-equipped vehicle designed to land at relatively low speeds. The skid-equipped landing gear is designed to attenuate the vertical landing energy of the vehicle at touchdown using crushable materials within the struts themselves. The vehicle then slides out as the vehicle horizontal energy is dissipated through the skids. A series of tests was conducted at Edwards Airforce Base (EAFB) in an attempt to quantify the drag force produced while "dragging" various X-38 landing gear skids across lakebed regions of varying surface properties. These data were then used to calculate coefficients of friction for each condition. Coefficient of friction information is critical for landing analyses as well as for landing gear load and interface load analysis. The skid specimens included full- and sub-scale V201 (space test vehicle) nose and main gear designs, a V131/V 132 (atmospheric flight test vehicles) main gear skid (actual flight hardware), and a newly modified, full-scale V201 nose -ear skid with substantially increased edge curvature as compared to its original design. Results of the testing are discussed along with comments on the relative importance of various parameters that influence skid stability and other dynamic behavior.

  10. An Overview of Landing Gear Dynamics

    Pritchard, Jocelyn

    1999-01-01

    One of the problems facing the aircraft community is landing gear dynamics, especially shimmy and brake-induced vibration. Although neither shimmy nor brake-induced vibrations are usually catastrophic, they can lead to accidents due to excessive wear and shortened life of gear parts and contribute to pilot and passenger discomfort. Recently, NASA has initiated an effort to increase the safety of air travel by reducing the number of accidents by a factor of five in ten years. This safety initiative has spurred an increased interest in improving landing gear design to minimize shimmy and brake-induced vibration that are still largely misunderstood phenomena. In order to increase the understanding of these problems, a literature survey was performed. The major focus of the paper is to summarize work documented from the last ten years to highlight the latest efforts in solving these vibration problems. Older publications are included to understand the longevity of the problem and the findings from earlier researchers. The literature survey revealed a variety of analyses, testing, modeling, and simulation of aircraft landing gear. Experimental validation and characterization of shimmy and brake-induced vibration of aircraft landing gear are also reported. This paper presents an overview of the problem documented in the references together with a history of landing gear dynamic problems and solutions. Based on the assessment of this survey, recommendations of the most critically needed enhancements to the state of the art are given.

  11. Ultrasonic test of highly stressed gear shafts

    Schreiner, T. [Siemens AG, Power Generation, KWU, Muelheim (Germany); Heinrich, W. [Siemens AG, Power Generation, KWU, Berlin (Germany); Achtzehn, J. [Siemens AG, Power Generation, ICVW, Erlangen (Germany); Hensley, H. [Siemens Power Generation (Germany)

    1998-12-31

    In the power plant industry, gears are used for increasingly higher turbine capacities. Efficiency enhancements, particularly for the combined gas and steam turbine process, lead to an increase in stresses, even for high-performance gears. Consequently, the requirements for non-destructive material testing are on the increase as well. At Siemens KWU, high-performance gears are used so far only for gas turbines with lower rating (65 MW) to adapt the gas turbine speed (5413 rpm) to the generator speed (3000 rpm/ 50 Hz or 3600 rpm/60 Hz). The gear train consists of a forged and case-hardened wheel shaft and pinion shaft made of material 17 CrNiMo 6, where the wheel shaft can be either a solid or a hollow shaft. Dimensions are typically 2.3 m length and 1 m diameter. As a rule, pinion shafts are solid. The gear design, calling for an additional torsion shaft turning inside the hollow wheel shaft, can absorb more torsional load surges and is more tolerant of deviations during gear train alignment. This design requires two additional forgings (torsion shaft and hub) and an additional bearing 2 refs.

  12. Systems and Methods for Implementing Bulk Metallic Glass-Based Strain Wave Gears and Strain Wave Gear Components

    Hofmann, Douglas C. (Inventor); Wilcox, Brian (Inventor)

    2016-01-01

    Bulk metallic glass-based strain wave gears and strain wave gear components. In one embodiment, a strain wave gear includes: a wave generator; a flexspline that itself includes a first set of gear teeth; and a circular spline that itself includes a second set of gear teeth; where at least one of the wave generator, the flexspline, and the circular spline, includes a bulk metallic glass-based material.

  13. A hypothetical immunemediated unifying mechanism for the Holmes-Adie syndrome

    C. M. de Castro Costa

    1988-06-01

    Full Text Available The Holmes-Adie syndrome consists of pupillotonia, arreflexia and autonomic dysfunction. Some explanations for these different symptoms have been attempted, centred upen neuropathological and electrophysiological findings. A hypothetical immunemediated mechanism, as in the Guillain Barré syndrome, is presented in this paper for explaining the three chief symptoms of the syndrome.

  14. FATIGUE PROPERTIES OF AUSTEMPERED DUCTILE IRON (ADI)IN WATER ENVIRONMENT

    Q.Z.Cai; B.K.Wei; Y.Tanaka

    2004-01-01

    The acicular ferrite in austempered ductile iron(ADI)matrix around graphite was corroded preferentially in wet condition,promoting crack origination and propagation and resulting in the disappearance of ADI fatigue limit.ADI fatigue strength was gradually reduced with increasing the time of test and was reduced by 50% in wet condition at 107 cycles compared with the fatigue limit in dry condition.The fatigue strength variation of ferritic ductile iron in wet condition was similar to that of ADI.The ferritic ductile iron,however,has better corrosion resistance so that the fatigue strength was lowered only by 10% in wet condition at 107 cycles compared with the fatigue limit in dry condition.On the other hand,the fatigue limits of A DI and ferritic ductile iron were dropped by 32% and 25% in tap water dipping 480h/dry condition respectively compared with those in dry condition.The reduction of fatigue limit was attributed to corrosion pits formation correlated with stress concentration,resulting in origination and propagation of fatigue crack.

  15. Laser Heat Treatment on Gear Surface and Its Practical Application

    MA Chun-yin; DAI Zhong-sen; SU Bao-rong

    2004-01-01

    Making gears with hardened tooth flank is one of the important developments in gear manufacturing. However, the conventional heat treating methods have a common shortcoming--producing big deformation. In this work, we demonstrate, by study, experiment and practical use, that not only has the laser heat treatment solved the difficult problems in conventional technique, but also it has great superiority. The use cases proved that the laser-treated gears are able to substitute for all the gears including gears with complicated shape, high precision and high performance imported gears and all those gears that cannot be manufactured by conventional methods. Moreover, our laser-treated gears have won quite good economic benefit.Obviously, the laser heat treatment for gears is a highly competitive technique having good prospects.

  16. Research on the Problem of Spur Gear Teeth Contact in the Car Gear Box

    Viktor Skrickij

    2011-04-01

    Full Text Available The article presents research on the problem of two gear contact in the car gearbox. Contact stiffness is evaluated for the whole period of mesh. Also, contact stresses are evaluated in the contact place. The presented method can be used for calculating spur gear.Article in Lithuanian

  17. Model-Checking Real-Time Properties of an Aircraft Landing Gear System Using Fiacre

    Berthomieu, Bernard; Dal Zilio, Silvano; Fronc, Lukasz

    2014-01-01

    International audience We describe our experience with modeling the landing gear system of an aircraft using the formal specification language Fiacre. Our model takes into account the behavior and timing properties of both the physical parts and the control software of this system. We use this formal model to check safety and real-time properties on the system but also to find a safe bound on the maximal time needed for all gears to be down and locked (assuming the absence of failures). Ou...

  18. Nonlinear parametrically excited vibration and active control of gear pair system with time-varying characteristic

    刘爽; 王进进; 刘金杰; 李雅倩

    2015-01-01

    In the present work, we investigate the nonlinear parametrically excited vibration and active control of a gear pair system involving backlash, time-varying meshing stiffness and static transmission error. Firstly, a gear pair model is established in a strongly nonlinear form, and its nonlinear vibration characteristics are systematically investigated through different approaches. Several complicated phenomena such as period doubling bifurcation, anti period doubling bifurcation and chaos can be observed under the internal parametric excitation. Then, an active compensation controller is designed to suppress the vibration, including the chaos. Finally, the effectiveness of the proposed controller is verified numerically.

  19. DETERMINATION OF TRANSMISSION GEAR RATIO IN MECHANICAL PART OF TRACTOR ELECTRO-MECHANICAL TRANSMISSION

    Ch. I. Zhdanovich

    2016-01-01

    Full Text Available A methodology has been developed for selection of gear number and transmission gear ratios in mechanical part of a wheel-type tractor with electro-mechanical transmission containing a propulsion asynchronous electric motor with variablefrequency control. The paper proposes to determine a transmission gear ratio on the basis of the following: provision of wheel torque dependence on tractor speed which is the best one for a traction process and during transfer from one gear to the other; provision of nominal operational mode of the electric motor for all tractor operations where it is working for a long period of time; provision of minimum possible number of gears; complete realization of internal combustion engine power on the tractor wheels at limit operational mode of the electric motor. As a characteristic of the asynchronous electric motor with variable-frequency control contains various portions which can be used either completely or partially due to operating conditions, the gear number is determined in the process of transmission gear ration finding but not prior to this. A wheel torque of the tractor with electro-mechanical transmission can be limited according to the following factors: grip of wheel with supporting surface; maximum power of an internal combustion engine which can be transferred to the wheels and a torque which is developed by a propulsion electric motor. It is not proposed to exceed nominal operational mode of the propulsion electric motor for all the operations of the tractor if it is working for a long period of time because in the case of significant excess of the nominal operational mode of the asynchronous electric motor its rather long operation leads to low efficiency and high losses in power, large heat liberation and consequently requires to develop more complicated system for electric motor cooling. An excess of nominal electric motor torque can be justified for short-term operational modes because in this case

  20. Kinetics of borided gear steels

    Ibrahim Gunes

    2013-06-01

    In this study, the case properties and diffusion kinetics of GS18NiMoCr36 (GS18), GS22NiMoCr56 (GS22) and GS32NiCrMo6.4 (GS32) gear steels borided in Ekabor-II powder were investigated by conducting a series of experiments at temperatures of 1123, 1173 and 1223 K for 2, 4 and 6 h. The boride layer was characterized by optical microscopy, X-ray diffraction technique and microVickers hardness tester. X-ray diffraction analysis of boride layers on the surface of the steels revealed the existence of FeB, Fe2B, CrB and Cr2B compounds. The thickness of the boride layer increases by increasing boriding time and temperature for all steels. The hardness of the boride compounds formed on the surface of the steels GS18, GS22 and GS32 ranged from 1624 to 1905 HV0,05, 1702 to 1948 HV0,05, and 1745 to 2034 HV0,05 respectively, whereas Vickers hardness values of the untreated steels GS18, GS22 and GS32 were 335 HV0,05, 358 HV0,05 and 411 HV0,05, respectively. The activation energies (Q) of borided steels were 228.644 kJ/mol for GS18, 280.609 kJ/mol for GS22 and 294.359 kJ/mol for GS32. The growth kinetics of the boride layers forming on the GS18, GS22 and GS32 steels and the thickness of boride layers were also investigated.

  1. Computer aided design and analysis of gear tooth geometry

    Chang, S. H.; Huston, R. L.

    1987-01-01

    A simulation method for gear hobbing and shaping of straight and spiral bevel gears is presented. The method is based upon an enveloping theory for gear tooth profile generation. The procedure is applicable in the computer aided design of standard and nonstandard tooth forms. An inverse procedure for finding a conjugate gear tooth profile is presented for arbitrary cutter geometry. The kinematic relations for the tooth surfaces of straight and spiral bevel gears are proposed. The tooth surface equations for these gears are formulated in a manner suitable for their automated numerical development and solution.

  2. A Computational Investigation of Gear Windage

    Hill, Matthew J.; Kunz, Robert F.

    2012-01-01

    A CFD method has been developed for application to gear windage aerodynamics. The goals of this research are to develop and validate numerical and modeling approaches for these systems, to develop physical understanding of the aerodynamics of gear windage loss, including the physics of loss mitigation strategies, and to propose and evaluate new approaches for minimizing loss. Absolute and relative frame CFD simulation, overset gridding, multiphase flow analysis, and sub-layer resolved turbulence modeling were brought to bear in achieving these goals. Several spur gear geometries were studied for which experimental data are available. Various shrouding configurations and free-spinning (no shroud) cases were studied. Comparisons are made with experimental data from the open literature, and data recently obtained in the NASA Glenn Research Center Gear Windage Test Facility. The results show good agreement with experiment. Interrogation of the validative and exploratory CFD results have led, for the first time, to a detailed understanding of the physical mechanisms of gear windage loss, and have led to newly proposed mitigation strategies whose effectiveness is computationally explored.

  3. RELIABILITY BASED DESIGN OF A GEAR BOX

    D.MADHUSEKHAR

    2014-08-01

    Full Text Available Reliability is the probability that a system, component or device will perform without failure for a specified period of time under specified operating conditions. The concept of reliability is of great importance in the design of various machine members. Conventional engineering design uses a deterministic approach. It disregards the fact that the material properties, the dimensions of the components and the externally applied loads are statistical in nature. In conventional design this uncertainties are covered with a factor of safety, which is not always successful. The growing trend towards reducing uncertainty and increasing reliability is to use the probabilistic approach. In the present work a three shaft four speed gear box and six speed gear box are designed using reliability principles. For the specified reliability of the system (Gear box, component reliability (Gear pair is calculated by considering the system as a series system. Design is considered to be safe and adequate if the probability of failure of gear box is less than or equal to a specified quantity in each of the two failure modes. . All the parameters affecting the design are considered as random variables and all the random variables are assumed to follow normal distribution. A computer program in C++ is developed to calculate the face widths in bending and surface failure modes. The larger one out of the two values is considered. By changing the variations in the design parameters, variations in the face widths are studied.

  4. Stabilization of the Gear-Grimshaw system on a periodic domain

    Capistrano-Filho, Roberto de A.; Komornik, Vilmos; Pazoto, Ademir F.

    2013-01-01

    This paper is devoted to the study of a nonlinear coupled system of two Korteweg-de Vries equations in a periodic domain under the effect of an internal damping term. The system was introduced Gear and Grimshaw to model the interactions of two-dimensional, long, internal gravity waves propagation in a stratified fluid. Designing a time-varying feedback law and using a Lyapunov approach we establish the exponential stability of the solutions in Sobolev spaces of any positive integral order.

  5. Improving backdrivability in geared rehabilitation robots.

    Nef, Tobias; Lum, Peter

    2009-04-01

    Many rehabilitation robots use electric motors with gears. The backdrivability of geared drives is poor due to friction. While it is common practice to use velocity measurements to compensate for kinetic friction, breakaway friction usually cannot be compensated for without the use of an additional force sensor that directly measures the interaction force between the human and the robot. Therefore, in robots without force sensors, subjects must overcome a large breakaway torque to initiate user-driven movements, which are important for motor learning. In this technical note, a new methodology to compensate for both kinetic and breakaway friction is presented. The basic strategy is to take advantage of the fact that, for rehabilitation exercises, the direction of the desired motion is often known. By applying the new method to three implementation examples, including drives with gear reduction ratios 100-435, the peak breakaway torque could be reduced by 60-80%. PMID:19184156

  6. Plasma Fairings for Quieting Aircraft Landing Gear Noise Project

    National Aeronautics and Space Administration — A major component of airframe noise for commercial transport aircraft is the deployed landing gear. The noise from the gear originates due to complex, unsteady...

  7. Data Fusion Tool for Spiral Bevel Gear Condition Indicator Data

    Dempsey, Paula J.; Antolick, Lance J.; Branning, Jeremy S.; Thomas, Josiah

    2014-01-01

    Tests were performed on two spiral bevel gear sets in the NASA Glenn Spiral Bevel Gear Fatigue Test Rig to simulate the fielded failures of spiral bevel gears installed in a helicopter. Gear sets were tested until damage initiated and progressed on two or more gear or pinion teeth. During testing, gear health monitoring data was collected with two different health monitoring systems. Operational parameters were measured with a third data acquisition system. Tooth damage progression was documented with photographs taken at inspection intervals throughout the test. A software tool was developed for fusing the operational data and the vibration based gear condition indicator (CI) data collected from the two health monitoring systems. Results of this study illustrate the benefits of combining the data from all three systems to indicate progression of damage for spiral bevel gears. The tool also enabled evaluation of the effectiveness of each CI with respect to operational conditions and fault mode.

  8. Vibration Control of MR Damper Landing Gear

    Disha Saxena

    2013-03-01

    Full Text Available In the field of Automation, Fuzzy Control Fuzzy control has significant merits which are utilized in intelligent controllers, especially for vibration control systems. This paper is concerned with the application aspects of the developed MR damper for landing gear system, to attenuate the sustained vibrations during the landing phase. Also a comparative study is made on the responses obtained from the MR damper landing gear by utilizing PID and Fuzzy PID controllers.Theory is a well-known technique to acquire the desired response of different non-linear systems.

  9. Measurement of Gear Tooth Dynamic Friction

    Rebbechi, Brian; Oswald, Fred B.; Townsend, Dennis P.

    1996-01-01

    Measurements of dynamic friction forces at the gear tooth contact were undertaken using strain gages at the root fillets of two successive teeth. Results are presented from two gear sets over a range of speeds and loads. The results demonstrate that the friction coefficient does not appear to be significantly influenced by the sliding reversal at the pitch point, and that the friction coefficient values found are in accord with those in general use. The friction coefficient was found to increase at low sliding speeds. This agrees with the results of disc machine testing.

  10. Improving bending stress in spur gears using asymmetric gears and shape optimization

    Pedersen, Niels Leergaard

    2010-01-01

    Bending stress plays a significant role in gear design wherein its magnitude is controlled by the nominal bending stress and the stress concentration due to the geometrical shape. The bending stress is indirectly related to shape changes made to the cutting tool. This work shows that the bending...... stress can be reduced significantly by using asymmetric gear teeth and by shape optimizing the gear through changes made to the tool geometry. However, to obtain the largest possible stress reduction a custom tool must be designed depending on the number of teeth, but the stress reductions found are not...

  11. DESIGN AND ANALYSIS OF A COMPOSITE BEVEL GEAR IN AN AUTOMOBILE DIFFERENTIAL GEAR BOX

    Mr. Rohit Sreekumar *, Prof. T. Jeyapoovan

    2016-01-01

    In automotive Industry,the differential gear plays an important role in power transmission as well as in the handling of the automobile.It transmits torque through three different shafts. This project deals with the design and optimization of the differential gear box through use of composite material. The solid modelling is done by using SOLIDWORKS. Static analysis is performed on the gear using Ni-CR steel, malleable cast iron, aluminium alloy and glass filled polyamide using ANSYS 14.5 The...

  12. Experimental assessment of low noise landing gear component design

    Dobrzynski, Werner; Chow, Leung Choi; Smith, Malcolm; Boillot, Antoine; Dereure, Olivier; Molin, Nicolas

    2009-01-01

    Landing gear related airframe noise is one of the dominant aircraft noise components at approach. It therefore is essential to particularly reduce landing gear noise. In the European SILENCER project, advanced low noise gears had been designed and tested at full scale. In the current European co-financed project TIMPAN (Technologies to IMProve Airframe Noise) still more advanced low noise design concepts were investigated and noise tested on a ¼ scaled main landing gear model in the German-Du...

  13. CAD SIMULATION & FEM ANALYSIS OF AIRCRAFT LANDING GEAR MECHANISM

    Nilesh W. Nirwan; Dilip G. Gangwani,

    2015-01-01

    Aircraft landing gear supports the entire weight of an aircraft during landing and ground operations. They are attached to primary structural members of the aircraft. The type of gear depends on the aircraft design and its intended use. Most landing gear has wheels to facilitate operation to and from hard surfaces, such as airport runways. Other gear feature skids for this purpose, such as those found on helicopters, balloon gondolas, and in the tail area of some tail dragger airc...

  14. 50 CFR 622.31 - Prohibited gear and methods.

    2010-10-01

    ... 50 Wildlife and Fisheries 8 2010-10-01 2010-10-01 false Prohibited gear and methods. 622.31... Management Measures § 622.31 Prohibited gear and methods. In addition to the prohibited gear/methods specified in this section, see §§ 622.33, 622.34, and 622.35 for seasonal/area prohibited gear/methods...

  15. Design, Modeling, Application and Analysis of Bevel Gears

    1 Engr.Rufus Ogbuka Chime ,Mnse , Mnimech

    2016-04-01

    Full Text Available Computer technology has touched all areas of today’s life, impacting how we obtain railway tickets, shop online and receive medical advice from remote location. Computer-based design analysis is nowadays a common activity in most development projects. Traditionally, the design field has been identified with particular end products, e.g., mechanical design, electrical design, ship design. In these fields, design work is largely based on specific techniques to foster certain product characteristics and principles The scope of this work includes, to design, to model the bevel gear, to select gear materials , to detailed factor safety in design and to analysis bevel gears. Gears are toothed elements that transmit rotary motion from one shaft to another. Gears are generally rugged and durable and their power transmission efficiency is as high as 98%. Gears are usually more costly than chains and belts. Bevel gears are gears where the axes of the two shafts intersect and the toothbearing faces of the gears themselves are conically shaped. Bevel gears are most often mounted on shafts that are 90 degrees apart, but can be designed to work at other angles as well. The pitch surface of bevel gears is a cone. Two bevel gears in mesh is known as bevel gearing. In bevel gearing, the pitch cone angles of the pinion and gear are to be determined from the shaft angle, i.e., the angle between the intersecting shafts. The bevel gear has many diverse applications such as locomotives, marine applications, automobiles, printing presses, cooling towers, power plants, steel plants, railway track inspection machines, etc.

  16. Design and finite element mode analysis of noncircular gear

    Lin, C.; Cheng, K.; Qin, D.; Zhu, C; Qiu, H; Ran, X

    2008-01-01

    The noncircular gear transmission is an important branch of the gear transmission, it is characterized by its compact structure, good dynamic equilibration and other advantages, and can be used in the automobile, engineering machine, ship, machine tool, aviation and spaceflight field etc. Studying on the dynamics feature of noncircular gear transmission can improve the ability to carry loads of, reduce the vibration and noise of, increase the life of the noncircular gear transmission machine,...

  17. Theoretical analysis on flow characteristics of melt gear pump

    Zhao, R. J.; Wang, J. Q.; Kong, F. Y.

    2016-05-01

    The relationship between Geometric parameters and theoretical flow of melt gear pump is revealed, providing a theoretical basis to melt gear pump design. The paper has an analysis of meshing movement of melt gear pump on the condition of four different tooth numbers, stack movement law and flow ripple. The regulation of flow pulsation coefficient is researched by MATLAB software. The modulus formula of melt gear pump is proposed, consistent with actual situation.

  18. 14 CFR 27.477 - Landing gear arrangement.

    2010-01-01

    ... 14 Aeronautics and Space 1 2010-01-01 2010-01-01 false Landing gear arrangement. 27.477 Section 27... AIRWORTHINESS STANDARDS: NORMAL CATEGORY ROTORCRAFT Strength Requirements Ground Loads § 27.477 Landing gear arrangement. Sections 27.235, 27.479 through 27.485, and 27.493 apply to landing gear with two wheels aft,...

  19. 14 CFR 25.483 - One-gear landing conditions.

    2010-01-01

    ... 14 Aeronautics and Space 1 2010-01-01 2010-01-01 false One-gear landing conditions. 25.483 Section... AIRWORTHINESS STANDARDS: TRANSPORT CATEGORY AIRPLANES Structure Ground Loads § 25.483 One-gear landing conditions. For the one-gear landing conditions, the airplane is assumed to be in the level attitude and...

  20. 14 CFR 29.477 - Landing gear arrangement.

    2010-01-01

    ... 14 Aeronautics and Space 1 2010-01-01 2010-01-01 false Landing gear arrangement. 29.477 Section 29... AIRWORTHINESS STANDARDS: TRANSPORT CATEGORY ROTORCRAFT Strength Requirements Ground Loads § 29.477 Landing gear arrangement. Sections 29.235, 29.479 through 29.485, and 29.493 apply to landing gear with two wheels aft,...

  1. 30 CFR 75.1404 - Automatic brakes; speed reduction gear.

    2010-07-01

    ... 30 Mineral Resources 1 2010-07-01 2010-07-01 false Automatic brakes; speed reduction gear. 75.1404... Automatic brakes; speed reduction gear. Each locomotive and haulage car used in an underground coal mine... brakes, locomotives and haulage cars shall be subject to speed reduction gear, or other similar...

  2. 46 CFR 167.65-25 - Steering gear tests.

    2010-10-01

    ... 46 Shipping 7 2010-10-01 2010-10-01 false Steering gear tests. 167.65-25 Section 167.65-25... SHIPS Special Operating Requirements § 167.65-25 Steering gear tests. On all nautical school ships making voyages of more than 48 hours' duration, the entire steering gear, the whistle, the means...

  3. 29 CFR 1915.116 - Use of gear.

    2010-07-01

    ... 29 Labor 7 2010-07-01 2010-07-01 false Use of gear. 1915.116 Section 1915.116 Labor Regulations...) OCCUPATIONAL SAFETY AND HEALTH STANDARDS FOR SHIPYARD EMPLOYMENT Gear and Equipment for Rigging and Materials Handling § 1915.116 Use of gear. (a) The provisions of this section shall apply to ship...

  4. 46 CFR 61.20-1 - Steering gear.

    2010-10-01

    ... 46 Shipping 2 2010-10-01 2010-10-01 false Steering gear. 61.20-1 Section 61.20-1 Shipping COAST... Periodic Tests of Machinery and Equipment § 61.20-1 Steering gear. (a) The marine inspector must inspect the steering gear at each inspection for certification for vessels whose Certificate of...

  5. 46 CFR 182.610 - Main steering gear.

    2010-10-01

    ... 46 Shipping 7 2010-10-01 2010-10-01 false Main steering gear. 182.610 Section 182.610 Shipping...) MACHINERY INSTALLATION Steering Systems § 182.610 Main steering gear. (a) A vessel must be provided with a main steering gear that is: (1) Of adequate strength and capable of steering the vessel at all...

  6. Molecular Dynamics Simulation of Carbon Nanotube Based Gears

    Han, Jie; Globus, Al; Jaffe, Richard; Deardorff, Glenn; Chancellor, Marisa K. (Technical Monitor)

    1996-01-01

    We used molecular dynamics to investigate the properties and design space of molecular gears fashioned from carbon nanotubes with teeth added via a benzyne reaction known to occur with C60. A modified, parallelized version of Brenner's potential was used to model interatomic forces within each molecule. A Leonard-Jones 6-12 potential was used for forces between molecules. One gear was powered by forcing the atoms near the end of the buckytube to rotate, and a second gear was allowed.to rotate by keeping the atoms near the end of its buckytube on a cylinder. The meshing aromatic gear teeth transfer angular momentum from the powered gear to the driven gear. A number of gear and gear/shaft configurations were simulated. Cases in vacuum and with an inert atmosphere were examined. In an extension to molecular dynamics technology, some simulations used a thermostat on the atmosphere while the hydrocarbon gear's temperature was allowed to fluctuate. This models cooling the gears with an atmosphere. Results suggest that these gears can operate at up to 50-100 gigahertz in a vacuum or inert atmosphere at room temperature. The failure mode involves tooth slip, not bond breaking, so failed gears can be returned to operation by lowering temperature and/or rotation rate. Videos and atomic trajectory files in xyz format are presented.

  7. 50 CFR 660.372 - Fixed gear sablefish fishery management.

    2010-10-01

    ... 50 Wildlife and Fisheries 9 2010-10-01 2010-10-01 false Fixed gear sablefish fishery management... West Coast Groundfish Fisheries § 660.372 Fixed gear sablefish fishery management. This section applies to the primary season for the fixed gear limited entry sablefish fishery north of 36° N. lat.,...

  8. 50 CFR 660.219 - Fixed gear identification and marking.

    2010-10-01

    ... 50 Wildlife and Fisheries 9 2010-10-01 2010-10-01 false Fixed gear identification and marking. 660.219 Section 660.219 Wildlife and Fisheries FISHERY CONSERVATION AND MANAGEMENT, NATIONAL OCEANIC AND... Groundfish-Limited Entry Fixed Gear Fisheries § 660.219 Fixed gear identification and marking. (a)...

  9. 50 CFR 648.51 - Gear and crew restrictions.

    2010-10-01

    ... Atlantic Sea Scallop Fishery § 648.51 Gear and crew restrictions. (a) Trawl vessel gear restrictions. Trawl... 50 Wildlife and Fisheries 8 2010-10-01 2010-10-01 false Gear and crew restrictions. 648.51 Section 648.51 Wildlife and Fisheries FISHERY CONSERVATION AND MANAGEMENT, NATIONAL OCEANIC AND...

  10. 50 CFR 697.23 - Restricted gear areas.

    2010-10-01

    ... 50 Wildlife and Fisheries 9 2010-10-01 2010-10-01 false Restricted gear areas. 697.23 Section 697.23 Wildlife and Fisheries FISHERY CONSERVATION AND MANAGEMENT, NATIONAL OCEANIC AND ATMOSPHERIC... Measures § 697.23 Restricted gear areas. (a) Resolution of lobster gear conflicts with fisheries...

  11. 50 CFR 654.25 - Prevention of gear conflicts.

    2010-10-01

    ... 50 Wildlife and Fisheries 8 2010-10-01 2010-10-01 false Prevention of gear conflicts. 654.25... Measures § 654.25 Prevention of gear conflicts. (a) No person may knowingly place in the management area... necessary and appropriate to prevent gear conflicts. Necessary prohibitions or restrictions will...

  12. AN ADI GALERKIN METHOD WITH MOVING FINITE ELEMENT SPACES FOR A CLASS OF SECOND-ORDER HYPERBOLIC EQUATIONS

    2001-01-01

    An alternating-direction implicit (ADI) Galerkin nuthod with moving finite element spaces is formulated for a class of second-order hyperbolic equations in two space variables. A priori H1-error estimate is derived.

  13. PROFILAKSA BOLESTI NOVOROĐENČADI UZROKOVANE BETA HEMOLITIČNIM STREPTOKOKOM IZ SKUPINE B

    Stanojević, Milan; Pavičić-Bošnjak, Anita; Matijević, Ratko; Mišković, Berivoj; Habek, Dubravko

    2009-01-01

    Beta hemolitični streptokok iz skupine B (BHSB) može izazvati vrlo tešku bolest u fetusa, novorođenčadi i dojenčadi. Aspiracija zaražene plodove vode može dovesti do smrti ploda, konatalne pnumonije ili sepse. Prolazak kroz zaraženi porodni kanal može izazvati kolonizaciju, ranu bolest tijekom prvih 7 dana života i kasnu bolest nakon prvoga tjedna pa sve do trećega mjeseca. Prevalencija bolesti bila je prije provođenja intrapartalne profilakse od 2 do 15 na 1000 živorođenih od čega je 80% otp...

  14. Suvremeni pristup liječenju retinopatije nedonoščadi

    Vatavuk, Zoran; Benčić, Goran; Andrijević Derk, Biljana; Mandić, Zdravko

    2008-01-01

    Retinopatija nedonoščadi obuhvaća vazoproliferativne promjene na mrežnici, koje nastaju kao posljedica prijevremenog rođenja, zbog kojeg dolazi do prekida normalnog razvoja krvnih žila mrežnice. U svijetu je ova bolest odgovorna za sljepoću više od 50.000 djece. U posljednjih 50 godina svijet je zabilježio tri velike epidemije retinopatije nedonoščadi, a posljednja epidemija traje još uvijek i obuhvaća zemlje Latinske Amerike i istočne Europe. Studije CRYO-ROP i ETROP pokazale su učinkovitost...

  15. Influência da adição de dimetil dicarbonato (DMDC) em vinhos tintos

    Lucas, Daniela da Costa

    2009-01-01

    A adição do conservante Dimetil Dicarbonato (DMDC) em vinho, foi permitida pela Comunidade Europeia desde 2006, com um limite máximo de 200 mg/L, atendendo às seguintes prescrições: a adição deve ser efectuada pouco antes do engarrafamento; o tratamento pode apenas ser aplicado a vinhos com teor de açúcares superior a 5g/L; o produto não deve ser detectável no vinho colocado no mercado. O DMDC permite a conservação do vinho durante longos períodos de tempo, eliminando vários tipos de micro...

  16. Chronic cough in the Holmes-Adie syndrome: association in five cases with autonomic dysfunction

    Kimber, J; Mitchell, D.; Mathias, C

    1998-01-01

    The Holmes-Adie syndrome consists of unilateral or bilateral tonic pupils with near light dissociation and tendon areflexia. It is associated with autonomic disturbances affecting sudomotor and vasomotor function. Five such patients are reported on who also had a troublesome chronic dry cough, which was of unknown aetiology and was resistant to a range of treatments. The cough may be related to involvement of afferent or efferent pathways in the vagus. Chronic cough may b...

  17. Reconsideration of the temporary ADI and refined exposure assessment for Sunset Yellow FCF (E 110

    EFSA Panel on Food Additives and Nutrient Sources added to food (ANS

    2014-07-01

    Full Text Available The Panel on Food Additives and Nutrient Sources added to Food (ANS Panel has previously provided a scientific opinion re-evaluating the safety of Sunset Yellow FCF (E 110 as a food additive in the EU and establishing a temporary acceptable daily intake (ADI of 1 mg/kg bw/day (EFSA ANS Panel, 2009. Following a request by the European Commission, the ANS Panel was asked to assess newly submitted data from a study conducted as a result of the recommendations contained in the 2009 opinion. In addition, EFSA was requested to carry out the refined exposure assessment of Sunset Yellow FCF. The new information assessed comprised an evaluation of the 28-day study report, the data considered by the Joint FAO/WHO Expert Committee on Food Additives (JECFA in its latest evaluation from 2011, and any additional toxicological information that had become available since the completion of the previous evaluation by the ANS Panel. The ANS Panel has considered that the newly submitted data from the 28-day study and the overall available toxicological database on Sunset Yellow FCF provides a basis to revise the established temporary ADI and concluded that, based on the NOAEL of 375 mg/kg bw/day from the long-term feeding study in rats and an uncertainty factor of 100, a new ADI for Sunset Yellow FCF of 4 mg/kg bw/day can be established, in agreement with the latest evaluation by JECFA. Exposure estimates for Sunset Yellow FCF based both on the currently authorised MPLs and reported use levels provided are well below the new ADI of 4 mg/kg bw/day for all population groups. Overall, the Panel concluded that, using data provided by the food industry and Member States, the reported uses and use levels of Sunset Yellow FCF (E 110 would not be of safety concern.

  18. Pengaruh Kewajiban Karyawan Terhadap Kewajiban Perusahaan Di Lihat Dari Sisi Etika Bisnis Pada PT. Adi Sarana Armada (ASSA) Cabang Medan

    Harahap, Teguh Ardiansyah

    2013-01-01

    This research titled “The effect of employee obligations to liability company in views of bussines ethic at PT. Adi Sarana Armada (ASSA) Chapter Medan”. The purpose of this study is to determine and analyze the effect of employee obligations to liability company in views of bussines ethic at PT. Adi Sarana Armada (ASSA) Chapter Medan. Methods of data analysis using descriptive method and quantitative methods, ie the Simple Linear Regression Analysis. Analyze data using statistical data pr...

  19. COMPARISON OF SOCIO ECONOMIC STATUS AND SOCIAL, EMOTIONAL AND BEHAVIOUR PROBLEM OF STUDENTS STUDYING IN ADI-DRAVIDAR WELFARE SCHOOLS

    R. Gnanadevan; G Sivakumar

    2015-01-01

    The aim of the study is to compare the socio economic status and social, emotional and behaviour problem of students studying in Adi-Dravidar welfare schools, for which the survey method has been adapted. Random sampling technique has been used for the present study for the selection of sample. The sample of the study includes the adolescent students studying in Adi- Dravidar Welfare School in Cuddalore District. The social, emotional and behaviour problem scale standardised by the R.Gn...

  20. Construction of novel Saccharomyces cerevisiae strains for bioethanol active dry yeast (ADY production.

    Daoqiong Zheng

    Full Text Available The application of active dry yeast (ADY in bioethanol production simplifies operation processes and reduces the risk of bacterial contamination. In the present study, we constructed a novel ADY strain with improved stress tolerance and ethanol fermentation performances under stressful conditions. The industrial Saccharomyces cerevisiae strain ZTW1 showed excellent properties and thus subjected to a modified whole-genome shuffling (WGS process to improve its ethanol titer, proliferation capability, and multiple stress tolerance for ADY production. The best-performing mutant, Z3-86, was obtained after three rounds of WGS, producing 4.4% more ethanol and retaining 2.15-fold higher viability than ZTW1 after drying. Proteomics and physiological analyses indicated that the altered expression patterns of genes involved in protein metabolism, plasma membrane composition, trehalose metabolism, and oxidative responses contribute to the trait improvement of Z3-86. This work not only successfully developed a novel S. cerevisiae mutant for application in commercial bioethanol production, but also enriched the current understanding of how WGS improves the complex traits of microbes.

  1. GEAR UP: Providing Opportunities or Conflict?

    Walsh, Rachael

    2008-01-01

    Since 1965 the federal government has attempted to provide low socioeconomic status students with equal access to postsecondary education through the Higher Education Act and its multiplicative programmatic efforts. Implemented as one such program in 1998, the Gaining Early Awareness and Readiness for Undergraduate Programs, or GEAR UP, has been…

  2. Work in Olkiluotto in top gear

    Several years are works in Olkiluoto executed in top gear - more than 4,000 operatives work in three shift operations for seven days a week. The fi rst deep repository for spent nuclear fuel has started to be constructed there as well. (author)

  3. Computing Contact Stresses In Gear Teeth

    Oswald, Fred B.; Somprakit, Paisan; Huston, Ronald L.

    1995-01-01

    Improved method of computing contact stresses in gear teeth accounts for complicating effects like those of static and sliding friction. Provides iterative procedure for determination of contact region and nodal contact forces along with contact stresses. Method based on equations and computational procedure incorporating these effects routinely.

  4. 50 CFR 648.123 - Gear restrictions.

    2010-10-01

    ... 50 Wildlife and Fisheries 8 2010-10-01 2010-10-01 false Gear restrictions. 648.123 Section 648.123 Wildlife and Fisheries FISHERY CONSERVATION AND MANAGEMENT, NATIONAL OCEANIC AND ATMOSPHERIC ADMINISTRATION, DEPARTMENT OF COMMERCE FISHERIES OF THE NORTHEASTERN UNITED STATES Management Measures for the Scup...

  5. 50 CFR 654.22 - Gear restrictions.

    2010-10-01

    ... 50 Wildlife and Fisheries 8 2010-10-01 2010-10-01 false Gear restrictions. 654.22 Section 654.22 Wildlife and Fisheries FISHERY CONSERVATION AND MANAGEMENT, NATIONAL OCEANIC AND ATMOSPHERIC ADMINISTRATION, DEPARTMENT OF COMMERCE STONE CRAB FISHERY OF THE GULF OF MEXICO Management Measures § 654.22...

  6. Prophylactic inspection of gears; Prophylaxe fuers Getriebe

    Thomas, Torsten

    2011-07-29

    Gears must be sound and functional in order to ensure perfect operation. Some manufacturers are offering a new generation of sensors for permanent monitoring of the lubricant status in the transmission system and of the number of particles contained in the lubricating oil.

  7. Automotive gear oil lubricant from soybean oil

    The use of lubricants that are based on renewable materials is rapidly increasing. Vegetable oils have good lubricity, wear protection and low volatility which are desired properties for automotive gear lubricant applications. Soybean oil is used widely in the lubricant industry due to its properti...

  8. Machinability of Austempered Ductile Iron (ADI) Produced by Integrated Green Technology of Continuous Casting-Heat Treatment Processes

    Meena, A.; El Mansori, M.; Ghidossi, P.

    2011-01-01

    This study presents the novel processing technique known as continuous casting-heat treatment processes to produce Austempered Ductile Iron (ADI) which is a new class of ductile iron. ADI is characterized by improved mechanical properties but has low machinability as compared to other cast irons and steel of similar strength. The novel technique is developed by the integration of casting (in die casting) and heat treatment processes in foundry to save cost energy and time. Specimens just after casting were austenitized at 930° C for 90 min and then austempered in fluidized bed at 380° C for 90 and 120 min. Hence, the effect of austempering time on the morphology of retained austenite and mechanical properties of the material were examined and compared with conventionally produced ADI. Drilling tests were then carried out to evaluate the machinability of ADI in terms of cutting forces, chip micro-hardness, chip morphology and surface roughness. The mechanical properties of ADI austempered for 120 min have found to be better as compare to the ADI austempered for 90 min.

  9. Stuck in gear: age-related loss of variable gearing in skeletal muscle.

    Holt, Natalie C; Danos, Nicole; Roberts, Thomas J; Azizi, Emanuel

    2016-04-01

    Skeletal muscles power a broad diversity of animal movements, despite only being able to produce high forces over a limited range of velocities. Pennate muscles use a range of gear ratios, the ratio of muscle shortening velocity to fiber shortening velocity, to partially circumvent these force-velocity constraints. Muscles operate with a high gear ratio at low forces; fibers rotate to greater angles of pennation, enhancing velocity but compromising force. At higher forces, muscles operate with a lower gear ratio; fibers rotate little so limiting muscle shortening velocity, but helping to preserve force. This ability to shift gears is thought to be due to the interplay of contractile force and connective tissue constraints. In order to test this hypothesis, gear ratios were determined in the medial gastrocnemius muscles of both healthy young rats, and old rats where the interaction between contractile and connective tissue properties was assumed to be disrupted. Muscle fiber and aponeurosis stiffness increased with age (PGear ratio decreased with increasing force in young (Pgearing is lost in old muscle. These findings support the hypothesis that variable gearing results from the interaction between contractile and connective tissues and suggest novel explanations for the decline in muscle performance with age. PMID:27030778

  10. The load capacity of PC/ABS spur gears and investigation of gear damage

    M.T. Demirci

    2009-11-01

    Full Text Available Purpose: Recently, Polyamide 66 and Teflon as plastic materials have been widely used at the manufacturing of gear mechanism. The purpose of the paper is to examinee the load capacity of PC/ABS spur gears and investigation of gear damage.Design/methodology/approach: In this study, usability of PC/ABS composite plastic materials as spur gear was investigated. PC/ABS gears were tested by applying three different loading at two different numbers of revolutions on the FZG experiment set.Findings: As a result of the experiments, load capability of PC/ABS materials was seen rather high, if one of the spur gear pair was steel (AISI 8620.Practical implications: In fact that, PC/ABS materials are durable against flame, air, ultraviolet lights and holding lower moisture than PA66 GFR 30 materials, the usage of them brings an advantage in many industrial areas.Originality/value: Using PC/ ABC materials provides many advantages due to fire, air and ultraviolet light durability and low moisture holding properties.

  11. Initial noise predictions for rudimentary landing gear

    Spalart, Philippe R.; Shur, Mikhail L.; Strelets, Mikhail Kh.; Travin, Andrey K.

    2011-08-01

    A four-wheel "rudimentary" landing gear (RLG) truck was designed for public-domain research, with a level of complexity which is manageable in current numerical simulations, and a weak Reynolds-number sensitivity. Experimental measurements of wall-pressure fluctuations are allowing a meaningful test of unsteady simulations with emphasis on noise generation. We present three Detached-Eddy Simulations (DES) using up to 18 million points in the high-order NTS code. The first is incompressible with the model placed in the wind tunnel, as requested for the 2010 workshop on Benchmark problems for Airframe Noise Computations (BANC-I), intended for force and surface-pressure studies. The second and third are at Mach 0.115 and Mach 0.23, with only one wall, a "ceiling" analogous to a wing (but infinite and inviscid), and are used to exercise far-field noise prediction by coupling the Detached-Eddy Simulations and a Ffowcs-Williams/Hawkings calculation. The results include wall-pressure, and far-field-noise intensities and spectra. The wall pressure signals in the three simulations are very similar and, in a comparison published separately, agree well with experiment and other simulations. In the absence of experimental noise data, the attention is focused on internal quality checks, by varying the permeable Ffowcs-Williams/Hawkings calculation surface and then by using only the solid surface. An unexpected finding at these Mach numbers is an apparent strong role for quadrupoles, revealed by a typical deficit of 3 dB in the solid-surface results, relative to the permeable-surface results. The solid-surface approach has variants, related to the presence of the ceiling (a plane of symmetry), which can increase this error further; there is little consensus on the exact configuration of the solid surfaces in the Ffowcs-Williams/Hawkings calculation procedure. Tentative theoretical arguments suggest that a balance somewhat in favor of quadrupoles over dipoles is plausible at Mach

  12. CNOOC Geared Up for 2008

    2008-01-01

    Propped up by soaring international oil prices and its rich offshore oil resources,CNOOC is well positioned to raise its output for 2008 Amid the dark prospects of a global economic downturn,Chinese oil suppliers have been able to sustain global pressure thanks to a stretched domestic oil supply.China National Offshore Oil Corp.(CNOOC),the largest offshore oil and gas producer of China,has

  13. RDS-21 Face-Gear Surface Durability Tests

    Lewicki, David G.; Heath, Gregory F.; Filler, Robert R.; Slaughter, Stephen C.; Fetty, Jason

    2007-01-01

    Experimental fatigue tests were performed to determine the surface durability life of a face gear in mesh with a tapered spur involute pinion. Twenty-four sets of gears were tested at three load levels: 7200, 8185, and 9075 lb-in face gear torque, and 2190 to 3280 rpm face gear speed. The gears were carburized and ground, shot-peened and vibro-honed, and made from VIM-VAR Pyrowear 53 steel per AMS 6308. The tests produced 17 gear tooth spalling failures and 7 suspensions. For all the failed sets, spalling occurred on at least one tooth of all the pinions. In some cases, the spalling initiated a crack in the pinion teeth which progressed to tooth fracture. Also, spalling occurred on some face gear teeth. The AGMA endurance allowable stress for a tapered spur involute pinion in mesh with a face gear was determined to be 275 ksi for the material tested. For the application of a tapered spur involute pinion in mesh with a face gear, proper face gear shim controlled the desired gear tooth contact pattern while proper pinion shim was an effective way of adjusting backlash without severely affecting the contact pattern.

  14. The aeronautics face-gear NC hobbing machining technology

    Wu, Canhui; Wang, Yanzhong

    2013-03-01

    Face-gear drives become the main direction of research for aeronautical drives because of their special advantages. Face-gear machining problems have became to baffle the embedded research for face-gear. The basal coordinate systems of face-gear hobbing were setted up according to the face-gear hobbing theory. The hobbing surface equation of facegear was established by using the equation of pinion tooth surface and matrix for coordinate transform based on the gear geometry and applied theory, then the hobbing tooth surface constrain conditions for dedendum undercutting were analyzed, at the same time, the hobbing nodal points were used to construct the three-dimensional basal worm model of face-gear hob by recurring to the three-dimensional software. Furthermore, the special hob for face-gear machining was designed and manufactured. The exact assembly and machining simulation were finished by using the program development software VC++6.0 and the UG customization function in the light of the face-gear hobbing theory. It validates the hob correctness and gets the gear hobbing program. According to the result of machining simulation, facegear numerical control(NC) hob machining was realized in the four-axis NC machine tool. It improves the cutting efficiency and establishs the base for face-gear grinding.

  15. Efficiency of fishing gears in the river Halda, Chittagong, Bangladesh

    Mohammad Arshad-Ul-Alam

    2015-12-01

    Full Text Available To determine the catch efficiency of fishing gears, catch per unit effort (CPUEdata were collected for two years during January 2007 to December 2008 from the river Halda. Analyses were done to examine the variation of CPUE among gears, studied sections, months and years. The mean CPUE for pooled data of all gears was 2.247±0.265 kg.gear-1day-1 and 2.697±0.355 kg.gear-1day-1 for 2007 and 2008 respectively. Among eight gear categories, bag nets yielded the highest CPUE during 2007 (5.957±0.704 kg.gear-1day-1 and seine nets during 2008 (7.288±1.477 kg.gear-1day-1. Among 31 gear types, small meshed bag nets yielded the highest CPUE (18.065±6.660 and 15.69±4.479 kg.gear-1day-1 during 2007 and 2008 respectively. CPUE was highest during March-April and September-November periods. Analysis of variance showed significant difference among catch rates of different fishing gears. The CPUE differed significantly among different months for net fence, gill net, cast net and scoop net during 2007; and for seine net, net fence, bag net and cast net during 2008.

  16. Dynamics of High-Speed Precision Geared Rotor Systems

    Lim Teik C.

    2014-07-01

    Full Text Available Gears are one of the most widely applied precision machine elements in power transmission systems employed in automotive, aerospace, marine, rail and industrial applications because of their reliability, precision, efficiency and versatility. Fundamentally, gears provide a very practical mechanism to transmit motion and mechanical power between two rotating shafts. However, their performance and accuracy are often hampered by tooth failure, vibrations and whine noise. This is most acute in high-speed, high power density geared rotor systems, which is the primary scope of this paper. The present study focuses on the development of a gear pair mathematical model for use to analyze the dynamics of power transmission systems. The theory includes the gear mesh representation derived from results of the quasi-static tooth contact analysis. This proposed gear mesh theory comprising of transmission error, mesh point, mesh stiffness and line-of-action nonlinear, time-varying parameters can be easily incorporated into a variety of transmission system models ranging from the lumped parameter type to detailed finite element representation. The gear dynamic analysis performed led to the discovery of the out-of-phase gear pair torsion modes that are responsible for much of the mechanical problems seen in gearing applications. The paper concludes with a discussion on effectual design approaches to minimize the influence of gear dynamics and to mitigate gear failure in practical power transmission systems.

  17. Investigation of Sideband Index Response to Prototype Gear Tooth Damage

    Dempsey, Paula J.

    2013-01-01

    The objective of this analysis was to evaluate the ability of gear condition indicators (CI) to detect contact fatigue damage on spiral bevel gear teeth. Tests were performed in the NASA Glenn Spiral Bevel Gear Fatigue Rig on eight prototype gear sets (pinion/gear). Damage was initiated and progressed on the gear and pinion teeth. Vibration data was measured during damage progression at varying torque values while varying damage modes to the gear teeth were observed and documented with inspection photos. Sideband indexes (SI) and root mean square (RMS) CIs were calculated from the time synchronous averaged vibration data. Results found that both CIs respond differently to varying torque levels, damage levels and damage modes

  18. Bevel gear driver and method having torque limit selection

    Cook, Joseph S., Jr. (Inventor)

    1994-01-01

    This invention comprises a torque drive mechanism utilizing axially translatable, mutually engageable transmission members having mating crown gears, driven and driving members with a three-element drive train being biased together by resilient means or by a fluid actuator system, the apparatus being operable to transmit a precisely controlled degree of torque to a driven member. The apparatus is applicable for use in hand tools and as a replacement for impact torque drivers, torque wrenches, motorized screw drivers, or the like, wherein the applied torque must be precisely controlled or limited. The bevel torque drive includes a drive gear which is axially displaceable and rotatable within cylindrical driver housing, a rotatable intermediate gear, and an output gear. Key rotationally secures displaceable gear with respect to input shaft but permits axial movement therebetween. A thrust bearing is preferably connected to the lower end of shaft for support to reduce play and friction between shaft and a transmission joint disc during rotation of the gear train. Coaxially mounted coiled spring is footed against displaceable gear for biasing the displaceable gear toward and into engagement with the intermediate gear for driving intermediate gear and output gear. Torque control is achieved by the use of straight or spiral beveled gears which are of configurations adapted to withdraw from mutual engagement upon the torque exceeding a predetermined limit. The novel, advantageous features of the invention include the configuration of the mating, crown gear sets and the axially translatable, slidable drive gear. The mechanism is capable of transmitting a high degree of torque within a narrow, compact transmission housing. The compact size and narrow, elongated configuration of the housing is particularly applicable for use in hand tools and in multiple torque driver mechanisms in which it is necessary to drive multiple fasteners which are located in close proximity. Prior

  19. Bevel gear driver and method having torque limit selection

    Cook, Joseph S., Jr.

    1994-08-01

    This invention comprises a torque drive mechanism utilizing axially translatable, mutually engageable transmission members having mating crown gears, driven and driving members with a three-element drive train being biased together by resilient means or by a fluid actuator system, the apparatus being operable to transmit a precisely controlled degree of torque to a driven member. The apparatus is applicable for use in hand tools and as a replacement for impact torque drivers, torque wrenches, motorized screw drivers, or the like, wherein the applied torque must be precisely controlled or limited. The bevel torque drive includes a drive gear which is axially displaceable and rotatable within cylindrical driver housing, a rotatable intermediate gear, and an output gear. Key rotationally secures displaceable gear with respect to input shaft but permits axial movement therebetween. A thrust bearing is preferably connected to the lower end of shaft for support to reduce play and friction between shaft and a transmission joint disc during rotation of the gear train. Coaxially mounted coiled spring is footed against displaceable gear for biasing the displaceable gear toward and into engagement with the intermediate gear for driving intermediate gear and output gear. Torque control is achieved by the use of straight or spiral beveled gears which are of configurations adapted to withdraw from mutual engagement upon the torque exceeding a predetermined limit. The novel, advantageous features of the invention include the configuration of the mating, crown gear sets and the axially translatable, slidable drive gear. The mechanism is capable of transmitting a high degree of torque within a narrow, compact transmission housing. The compact size and narrow, elongated configuration of the housing is particularly applicable for use in hand tools and in multiple torque driver mechanisms in which it is necessary to drive multiple fasteners which are located in close proximity. Prior

  20. Hypoxia-induced nitric oxide production and tumour perfusion is inhibited by pegylated arginine deiminase (ADI-PEG20).

    Burrows, Natalie; Cane, Gaelle; Robson, Mathew; Gaude, Edoardo; J Howat, William; Szlosarek, Peter W; Pedley, R Barbara; Frezza, Christian; Ashcroft, Margaret; Maxwell, Patrick H

    2016-01-01

    The hypoxic tumour microenvironment represents an aggressive, therapy-resistant compartment. As arginine is required for specific hypoxia-induced processes, we hypothesised that arginine-deprivation therapy may be useful in targeting hypoxic cancer cells. We explored the effects of the arginine-degrading agent ADI-PEG20 on hypoxia-inducible factor (HIF) activation, the hypoxia-induced nitric oxide (NO) pathway and proliferation using HCT116 and UMUC3 cells and xenografts. The latter lack argininosuccinate synthetase (ASS1) making them auxotrophic for arginine. In HCT116 cells, ADI-PEG20 inhibited hypoxic-activation of HIF-1α and HIF-2α, leading to decreased inducible-nitric oxide synthase (iNOS), NO-production, and VEGF. Interestingly, combining hypoxia and ADI-PEG20 synergistically inhibited ASS1. ADI-PEG20 inhibited mTORC1 and activated the unfolded protein response providing a mechanism for inhibition of HIF and ASS1. ADI-PEG20 inhibited tumour growth, impaired hypoxia-associated NO-production, and decreased vascular perfusion. Expression of HIF-1α/HIF-2α/iNOS and VEGF were reduced, despite an increased hypoxic tumour fraction. Similar effects were observed in UMUC3 xenografts. In summary, ADI-PEG20 inhibits HIF-activated processes in two tumour models with widely different arginine biology. Thus, ADI-PEG20 may be useful in the clinic to target therapy-resistant hypoxic cells in ASS1-proficient tumours and ASS1-deficient tumours. PMID:26972697

  1. Some characteristics of the design of heads for the cutting of bevel gears with negative curvature of the circular-arc tooth line

    Savinov, A. P.; Iastrebov, V. M.

    The principles of the design of the external and internal finishing cutters of heads for the machining of bevel gears with negative curvature of the circular-arc tooth line are examined. The differences between heads for the machining of circular-arc teeth with positive and negative curvatures are discussed. A newly developed design of a head for the machining of bevel gears with negative curvature of the circular-arc tooth is described as an example.

  2. Aeroacoustic Analysis of a Simplified Landing Gear

    Lockard, David P.; Khorrami, Mehdi, R.; Li, Fei

    2004-01-01

    A hybrid approach is used to investigate the noise generated by a simplified landing gear without small scale parts such as hydraulic lines and fasteners. The Ffowcs Williams and Hawkings equation is used to predict the noise at far-field observer locations from flow data provided by an unsteady computational fluid dynamics calculation. A simulation with 13 million grid points has been completed, and comparisons are made between calculations with different turbulence models. Results indicate that the turbulence model has a profound effect on the levels and character of the unsteadiness. Flow data on solid surfaces and a set of permeable surfaces surrounding the gear have been collected. Noise predictions using the porous surfaces appear to be contaminated by errors caused by large wake fluctuations passing through the surfaces. However, comparisons between predictions using the solid surfaces with the near-field CFD solution are in good agreement giving confidence in the far-field results.

  3. Gear Windage Modeling Progress - Experimental Validation Status

    Kunz, Rob; Handschuh, Robert F.

    2008-01-01

    In the Subsonics Rotary Wing (SRW) Project being funded for propulsion work at NASA Glenn Research Center, performance of the propulsion system is of high importance. In current rotorcraft drive systems many gearing components operate at high rotational speed (pitch line velocity > 24000 ft/ min). In our testing of high speed helical gear trains at NASA Glenn we have found that the work done on the air - oil mist within the gearbox can become a significant part of the power loss of the system. This loss mechanism is referred to as windage. The effort described in this presentation is to try to understand the variables that affect windage, develop a good experimental data base to validate, the analytical project being conducted at Penn State University by Dr. Rob Kunz under a NASA SRW NRA. The presentation provides an update to the status of these efforts.

  4. Innovative process chains for crankshafts and gears

    Denkena, B.; Becker, J.C.; Kramer, N.; Catoni, F. [Hannover Univ. (DE). Inst. of Production Engineering and Machine Tools (IFW)

    2005-07-01

    Precision forged parts offer a great potential regarding strength but also process chain efficiency. Nevertheless, varying stock allowances call for powerful grinding processes to ensure an economical production. Vitrified bonded CBN tools offer a potential which is not fully used in crankshaft and gear grinding because of process specific limits. The complex geometry of grinding tools used in continuous generating gear grinding usually causes dressing speed ratios far larger than those common for grinding wheels of simple geometry. In this paper the effects of the dressing speed ratio are discussed and general strategies to improve the speed ratio are offered. In path controlled grinding of crankshafts the complex geometry and the varying stiffness of the crankshafts causes differing form and geometrical errors, depending on the crankshaft dimensions and the deviation. In this paper the effects of typical deflections are presented and a general strategy to correct these deviations is discussed. (orig.)

  5. International

    This rubric reports on 10 short notes about international economical facts about nuclear power: Electricite de France (EdF) and its assistance and management contracts with Eastern Europe countries (Poland, Hungary, Bulgaria); Transnuclear Inc. company (a 100% Cogema daughter company) acquired the US Vectra Technologies company; the construction of the Khumo nuclear power plant in Northern Korea plays in favour of the reconciliation between Northern and Southern Korea; the delivery of two VVER 1000 Russian reactors to China; the enforcement of the cooperation agreement between Euratom and Argentina; Japan requested for the financing of a Russian fast breeder reactor; Russia has planned to sell a floating barge-type nuclear power plant to Indonesia; the control of the Swedish reactor vessels of Sydkraft AB company committed to Tractebel (Belgium); the renewal of the nuclear cooperation agreement between Swiss and USA; the call for bids from the Turkish TEAS electric power company for the building of the Akkuyu nuclear power plant answered by three candidates: Atomic Energy of Canada Limited (AECL), Westinghouse (US) and the French-German NPI company. (J.S.)

  6. Dynamics of Simple Planet Gearing Model

    Půst, Ladislav; Pešek, Luděk

    Praha : Institute of Theoretical and Applied Mechanics ASCR, v. v. i, 2015 - (Náprstek, J.; Fischer, C.). s. 246-247 ISBN 978-80-86246-42-0. ISSN 1805-8248. [Engineering mechanics 2015 /21./. 11.05.2015-14.05.2015, Svratka] R&D Projects: GA TA ČR(CZ) TA04011656 Institutional support: RVO:61388998 Keywords : planet gearing box * flexible pin * free and forced vibration * response curves Subject RIV: BI - Acoustics

  7. Numerical simulation of nanopulse penetration of biological matter using the ADI-FDTD method

    Zhu, Fei

    Nanopulses are ultra-wide-band (UWB) electromagnetic pulses with pulse duration of only a few nanoseconds and electric field amplitudes greater than 105 V/m. They have been widely used in the development of new technologies in the field of medicine. Therefore, the study of the nanopulse bioeffects is important to ensure the appropriate application with nanopulses in biomedical and biotechnological settings. The conventional finite-difference time-domain (FDTD) method for solving Maxwell's equations has been proven to be an effective method to solve the problems related to electromagnetism. However, its application is restricted by the Courant, Friedrichs, and Lewy (CFL) stability condition that confines the time increment and mesh size in the computation in order to prevent the solution from being divergent. This dissertation develops a new finite difference scheme coupled with the Cole-Cole expression for dielectric coefficients of biological tissues to simulate the electromagnetic fields inside biological tissues when exposed to nanopulses. The scheme is formulated based on the Yee's cell and alternating direction implicit (ADI) technique. The basic idea behind the ADI technique is to break up every time step into two half-time steps. At the first half-step, the finite difference operator on the right-hand side of the Maxwell's equation is implicit only along one coordinate axis direction. At the second half-step, the finite difference operator on the right-hand side of the Maxwell's equation is implicit only along the other coordinate axis direction. As such, only tridiagonal linear systems are solved. In this numerical method, the Cole-Cole expression is approximated by a second-order Taylor series based on the z-transform method. In addition, the perfectly matched layer is employed for the boundary condition, and the total/scattered field technique is employed to generate the plane wave in order to prevent the wave reflection. The scheme is tested by numerical

  8. La carnavalización del Archivo en Adiós, Ayacucho de Julio Ortega

    Quiroz Ciriaco, Victor Felipe Segundo

    2014-01-01

    En Adiós Ayacucho (1986/2008), del escritor peruano Julio Ortega, se cuestiona que la ideología patente en la producción textual dominante de la época de la Imposición Colonial (siglo XVI) continúa operando, a fines del siglo XX, en la lógica del discurso antropológico, tercer relato maestro empleado para narrar Latinoamérica. Por ello, planteamos que la obra de Ortega se configura como una variante de las ficciones del Archivo. Además, establecemos que el recorrido narrativo del protagonista...

  9. An average/deprivation/inequality (ADI analysis of chronic disease outcomes and risk factors in Argentina

    De Maio Fernando G

    2009-06-01

    Full Text Available Abstract Background Recognition of the global economic and epidemiological burden of chronic non-communicable diseases has increased in recent years. However, much of the research on this issue remains focused on individual-level risk factors and neglects the underlying social patterning of risk factors and disease outcomes. Methods Secondary analysis of Argentina's 2005 Encuesta Nacional de Factores de Riesgo (National Risk Factor Survey, N = 41,392 using a novel analytical strategy first proposed by the United Nations Development Programme (UNDP, which we here refer to as the Average/Deprivation/Inequality (ADI framework. The analysis focuses on two risk factors (unhealthy diet and obesity and one related disease outcome (diabetes, a notable health concern in Latin America. Logistic regression is used to examine the interplay between socioeconomic and demographic factors. The ADI analysis then uses the results from the logistic regression to identify the most deprived, the best-off, and the difference between the two ideal types. Results Overall, 19.9% of the sample reported being in poor/fair health, 35.3% reported not eating any fruits or vegetables in five days of the week preceding the interview, 14.7% had a BMI of 30 or greater, and 8.5% indicated that a health professional had told them that they have diabetes or high blood pressure. However, significant variation is hidden by these summary measures. Educational attainment displayed the strongest explanatory power throughout the models, followed by household income, with both factors highlighting the social patterning of risk factors and disease outcomes. As educational attainment and household income increase, the probability of poor health, unhealthy diet, obesity, and diabetes decrease. The analyses also point toward important provincial effects and reinforce the notion that both compositional factors (i.e., characteristics of individuals and contextual factors (i.e., characteristics

  10. Silagem de capim-elefante com a adição de casca de soja

    Lima, Paulo Guataçara da Costa

    2012-01-01

    Resumo: O presente trabalho teve por objetivo, apresentar uma alternativa à confecção de silagem de capim-elefante (Pennisetum purpureum Schumach.), sem se fazer a pré-secagem, quando a planta apresenta grande quantidade de água. O baixo teor de matéria seca no estádio vegetativo dessa forragem é o maior problema no processo fermentativo. O aumento da matéria seca, através da adição da casca de soja, resíduo alimentar barato e de baixo teor de umidade, tem por finalidade controlar as fermenta...

  11. Face Gear Technology for Aerospace Power Transmission Progresses

    2005-01-01

    The use of face gears in an advanced rotorcraft transmission design was first proposed by the McDonnell Douglas Helicopter Company during their contracted effort with the U.S. Army under the Advanced Rotorcraft Transmission (ART) program. Face gears would be used to turn the corner between the horizontal gas turbine engine and the vertical output rotor shaft--a function currently done by spiral bevel gears. This novel gearing arrangement would substantially lower the drive system weight partly because a face gear mesh would be used to split the input power between two output gears. However, the use of face gears and their ability to operate successfully at the speeds and loads required for an aerospace environment was unknown. Therefore a proof-of-concept phase with an existing test stand at the NASA Lewis Research Center was pursued. Hardware was designed that could be tested in Lewis' Spiral Bevel Gear Test Rig. The initial testing indicated that the face gear mesh was a feasible design that could be used at high speeds and load. Surface pitting fatigue was the typical failure mode, and that could lead to tooth fracture. An interim project was conducted to see if slight modifications to the gear tooth geometry or an alternative heat treating process could overcome the surface fatigue problems. From the initial and interim tests, it was apparent that for the surface fatigue problems to be overcome the manufacturing process used for this component would have to be developed to the level used for spiral bevel gears. The current state of the art for face gear manufacturing required using less than optimal gear materials and manufacturing techniques because the surface of the tooth form does not receive final finishing after heat treatment as it does for spiral bevel gears. This resulted in less than desirable surface hardness and manufacturing tolerances. An Advanced Research and Projects Agency (ARPA) Technology Reinvestment Project has been funded to investigate

  12. Improving fishing effort descriptors: Modelling engine power and gear-size relations of five European trawl fleets

    Eigaard, Ole Ritzau; Rihan, Dominic; Graham, Norman;

    2011-01-01

    Based on information from an international inventory of gears currently deployed by trawlers in five European countries, the relationship between vessel engine power and trawl size is quantified for different trawl types, trawling techniques and target species. Using multiplicative modelling it i...

  13. Bifurcation phenomena in internal dynamics of gear systems

    Hortel, Milan; Škuderová, Alena

    2007-01-01

    Roč. 1, č. 1 (2007), s. 53-62. ISSN 1802-680X. [Computational Mechanics 2007. Hrad Nečtiny, 05.11.2007-07.11.2007] R&D Projects: GA ČR(CZ) GA101/07/0884 Institutional research plan: CEZ:AV0Z20760514 Keywords : nonlinear dynamics * parametric systems * motions with impacts Subject RIV: BI - Acoustics

  14. DESIGN IMPROVEMENT OF THE LOCOMOTIVE RUNNING GEARS

    S. V. Myamlin

    2013-09-01

    Full Text Available Purpose. To determine the dynamic qualities of the mainline freight locomotives characterizing the safe motion in tangent and curved track sections at all operational speeds, one needs a whole set of studies, which includes a selection of the design scheme, development of the corresponding mathematical model of the locomotive spatial fluctuations, construction of the computer calculation program, conducting of the theoretical and then experimental studies of the new designs. In this case, one should compare the results with existing designs. One of the necessary conditions for the qualitative improvement of the traction rolling stock is to define the parameters of its running gears. Among the issues related to this problem, an important place is occupied by the task of determining the locomotive dynamic properties on the stage of projection, taking into account the selected technical solutions in the running gear design. Methodology. The mathematical modeling studies are carried out by the numerical integration method of the dynamic loading for the mainline locomotive using the software package «Dynamics of Rail Vehicles » («DYNRAIL». Findings. As a result of research for the improvement of locomotive running gear design it can be seen that the creation of the modern locomotive requires from engineers and scientists the realization of scientific and technical solutions. The solutions enhancing design speed with simultaneous improvement of the traction, braking and dynamic qualities to provide a simple and reliable design, especially the running gear, reducing the costs for maintenance and repair, low initial cost and operating costs for the whole service life, high traction force when starting, which is as close as possible to the ultimate force of adhesion, the ability to work in multiple traction mode and sufficient design speed. Practical Value. The generalization of theoretical, scientific and methodological, experimental studies aimed

  15. 14 CFR 23.729 - Landing gear extension and retraction system.

    2010-01-01

    ... 14 Aeronautics and Space 1 2010-01-01 2010-01-01 false Landing gear extension and retraction... Design and Construction Landing Gear § 23.729 Landing gear extension and retraction system. (a) General. For airplanes with retractable landing gear, the following apply: (1) Each landing gear...

  16. 78 FR 68817 - Proposed Information Collection; Comment Request; Northeast Region Gear Identification

    2013-11-15

    ... Region Gear Identification AGENCY: National Marine Fisheries Service (NMFS), National Oceanic and.... Abstract This notice is for the extension of Paperwork Reduction Act requirements regarding fishing gear... fishing gear mark the gear with specified information. The gear marking requirements provide vessel...

  17. A Lightweight Model for Gear Mesh Dynamics Incorporating Variable Mesh Stiffness

    Fokas Nikolaos

    2015-01-01

    Full Text Available Variable stiffness of the gear tooth mesh for a pair of spur gears is computed using an accurate lightweight mathematical formulation. This is used to simulate gear dynamic behavior. Gear eigenfrequencies are calculated for the SDOF system and correlated with gear physical properties and the effect of stiffness variation during a mesh cycle is studied.

  18. Displaceable Spur Gear Torque Controlled Driver and Method

    Cook, Joseph S., Jr. (Inventor)

    1996-01-01

    Methods and apparatus are provided for a torque driver including a laterally displaceable gear support member to carry an output spur gear. A biasing assembly biases the output spur gear into engagement with a pinion to which is applied an input torque greater than a desired output torque limit for a threaded fastener such as a nut or screw. A coiled output linkage connects the output spur gear with a fastener adaptor which may be a socket for a nut. A gear tooth profile provides a separation force that overcomes the bias to limit torque at the desired torque limit. Multiple fasteners may be rotated simultaneously to a desired torque limit if additional output spur gears are provided. A gauged selector mechanism is provided to laterally displace multiple driven members for fasteners arranged in differing configurations. The torque limit is selectably adjustable and may be different for fasteners within the same fastener configuration.

  19. Displaceable spur gear torque controlled driver and method

    Cook, Joseph S., Jr.

    1994-08-01

    Methods and apparatus are provided for a torque driver including a laterally displaceable gear support member to carry an output spur gear. A biasing assembly biases the output spur gear into engagement with a pinion to which is applied an input torque greater than a desired output torque limit for a threaded fastener such as a nut or screw. A coiled output linkage connects the output spur gear with a fastener adaptor which may be a socket for a nut. A gear tooth profile provides a separation force that overcomes the bias to limit torque at the desired torque limit. Multiple fasteners may be rotated simultaneously to a desired torque limit if additional output spur gears are provided. A gauged selector mechanism is provided to laterally displace multiple driver members for fasteners arranged in differing configurations. The torque limit is selectably adjustable and may be different for fasteners within the same fastener configuration.

  20. Prediction of potential failures in hydraulic gear pumps

    E. Lisowski

    2010-07-01

    Full Text Available Hydraulic gear pumps are used in many machines and devices. In hydraulic systems of machines gear pumps are main component ofsupply unit or perform auxiliary function. Gear pumps opposite to vane pumps are less complicated. They consists of such components as:housing, gear wheels, bearings, shaft, seal for rotation motion which are not very sensitive for damage and that is why they are using veryoften. However, gear pumps are break down from time to time. Usually damage of pump cause shutting down of machines and devices.One of the way for identifying potential failures and foreseeing their effects is a quality method. On the basis of these methods apreventing action might be undertaken before failure appear. In this paper potential failures and damages of a gear pump were presented bythe usage of matrix FMEA analysis.

  1. Influence of material and gear parameters on the safety of gearing in metallurgical industry

    S. Medvecká - Beňová

    2015-01-01

    Full Text Available This paper deals with the appropriate choice of parameters to obtain the desired level of safety of gears in a gearbox to drive the conveyor in the metallurgical industry under increased load. Steel with surface hardness up to 350 HBW, or heat treated steel with hardness of 500 - 650 HBW are used. As a final heat treatment are used surface hardening, cementation and hardening, nitridation. Good properties of heat-treated steels are at the correct thickness of the heat-treated layer of the tooth. Results are presented for dual-ratio gearbox with spur gears from operation of an integrated steel company.

  2. Marketing of fishing gear materials and fishing gear making in parts of Kainji Lake basin

    Ago, N.D.; Tafida, A.A.

    2005-01-01

    The importance of fishing gear in fishing cannot be over-emphasized; as without it fish cannot be obtained. The method used to catch fish affects the condition in which the product is landed. This means that a bad-catching method would produced bad fish to the consumer. To achieve the goal of self-sufficiency in fish production in Nigeria, there is need to address the lingering problems of fishing gear and craft technology, especially in terms of availability of materials and their cost. The ...

  3. HEALTH MONITORING OF ELECTRICAL ACTUATORS FOR LANDING GEARS

    Phillips, Paul

    2012-01-01

    There are numerous benefits associated with replacing hydraulic actuators with electrical counterparts as part of an all electric landing gear including reduced consumption of non-propulsive engine power, reduced weight, reduced cost and the elimination of hydraulic systems. The development of health monitoring systems to support the introduction of electrical actuation systems into landing gears will aid in guaranteeing reliability and to optimise landing gear maintenance activ...

  4. Prediction of Landing Gear Noise Reduction and Comparison to Measurements

    Lopes, Leonard V.

    2010-01-01

    Noise continues to be an ongoing problem for existing aircraft in flight and is projected to be a concern for next generation designs. During landing, when the engines are operating at reduced power, the noise from the airframe, of which landing gear noise is an important part, is equal to the engine noise. There are several methods of predicting landing gear noise, but none have been applied to predict the change in noise due to a change in landing gear design. The current effort uses the Landing Gear Model and Acoustic Prediction (LGMAP) code, developed at The Pennsylvania State University to predict the noise from landing gear. These predictions include the influence of noise reduction concepts on the landing gear noise. LGMAP is compared to wind tunnel experiments of a 6.3%-scale Boeing 777 main gear performed in the Quiet Flow Facility (QFF) at NASA Langley. The geometries tested in the QFF include the landing gear with and without a toboggan fairing and the door. It is shown that LGMAP is able to predict the noise directives and spectra from the model-scale test for the baseline configuration as accurately as current gear prediction methods. However, LGMAP is also able to predict the difference in noise caused by the toboggan fairing and by removing the landing gear door. LGMAP is also compared to far-field ground-based flush-mounted microphone measurements from the 2005 Quiet Technology Demonstrator 2 (QTD 2) flight test. These comparisons include a Boeing 777-300ER with and without a toboggan fairing that demonstrate that LGMAP can be applied to full-scale flyover measurements. LGMAP predictions of the noise generated by the nose gear on the main gear measurements are also shown.

  5. ANALYTICAL WEIGHT ESTIMATION OF UNCONVENTIONAL LANDING GEAR DESIGNS

    Parés Prat, Andreu; Borhani Coca, Dario; Munjulury, Raghu Chaitanya; Berry, Patrick

    2015-01-01

    Landing gear weight calculations can be carried out using statistical or analytical methods. Statistical methods were used in the past and offered quick group weights, however, they are not capable of computing with accuracy the weight of unconventional landing gears which have special geometries and performances. In this work, landing gear weight is computed using analytical methods. The procedure established by Kraus and Wille is acquired as a baseline so as to create a program able to deal...

  6. Tool Gear: Infrastructure for Building Parallel Programming Tools

    May, J M; Gyllenhaal, J

    2002-12-09

    Tool Gear is a software infrastructure for developing performance analysis and other tools. Unlike existing integrated toolkits, which focus on providing a suite of capabilities, Tool Gear is designed to help tool developers create new tools quickly. It combines dynamic instrumentation capabilities with an efficient database and a sophisticated and extensible graphical user interface. This paper describes the design of Tool Gear and presents examples of tools that have been built with it.

  7. STUDY ON WEAR AND DESTRUCTION OF HOB IN GEAR HOBBING

    2002-01-01

    The wear and destruction appearances of hobs are researched. The reasons of the wear and destruction of hobare analyzed. And the influence of the change of the hobbing force and the hobbing temperature on the wear and destruc-tion of hob in gear hobbing is also analyzed. In gear hobbing, the main wear mechanisms are adhesion and ploughingwhen cutting the 20CrMnTi gear using W 18Cr4V high-speed steel hob.

  8. Finite Element Residual Stress Analysis of Planetary Gear Tooth

    Jungang Wang; Yong Wang; Zhipu Huo

    2013-01-01

    A method to simulate residual stress field of planetary gear is proposed. In this method, the finite element model of planetary gear is established and divided to tooth zone and profile zone, whose different temperature field is set. The gear’s residual stress simulation is realized by the thermal compression stress generated by the temperature difference. Based on the simulation, the finite element model of planetary gear train is established, the dynamic meshing process is simulated, and in...

  9. Interactions of two co-propagating laser beams in underdense plasmas using a generalized Peaceman-Rachford ADI form

    A generalized Peaceman-Rachford (P-R) ADI form based on the regularized finite difference scheme is employed in order to study the interactions of two co-propagating laser beams in underdense plasmas. A numerical algorithm using the P-R ADI form is constructed for solution of coupled 2D time-dependent non-linear Schroedinger equations for quasineutral plasmas in paraxial approximation. The ability of the form to solve the equations is discussed, and its performance in simulating phenomena associated with the interactions in the presence of pondermotive nonlinearity and relativistic nonlinearity is examined. It is shown that the generalized P-R ADI form can accurately solve the coupled NLS equations. With simulation results, the form is shown to be suitable to simulate the interactions of two co-propagating laser beams with underdense plasma, and it can successively simulate the associated phenomena at varying conditions. (author)

  10. Gear-shaft linkage, especially for nuclear reactor coolant pumps

    The pump comprises: - inlet and outlet channels for the pumped fluid - a rotating shaft - a gear wheel mounted on the shaft by an axial locking nut which can support the axial hydraulic force - a thermal barrier above the gear wheel. A hydrostatic bearing fitted to the exterior surround of the gear wheel, the gear shaft linkage is made by at least a centering and locating device having a cylindrical span and an axial stop and another independent device which can take up the torque

  11. Offset Compound Gear Inline Two-Speed Drive

    Stevens, Mark A. (Inventor); Handschuh, Robert F. (Inventor); Lewicki, David G. (Inventor)

    2014-01-01

    A two-speed transmission having an input shaft and an output shaft, the transmission being capable of transitioning between fixed ratios, the high-range ratio being direct 1:1 and the low-range ratio being about 2:1. The transmission is a simple lightweight, yet robust, configuration utilizing only two gear meshes, being comprised of an input gear, a cluster gear, and an output gear. The transmission is controlled with a clutch and a sprag and with the input and output shafts turning in the same direction.

  12. Computer-aided design of bevel gear tooth surfaces

    Shuo, Hung Chang; Huston, Ronald L.; Coy, John J.

    1989-01-01

    This paper presents a computer-aided design procedure for generating bevel gears. The development is based on examining a perfectly plastic, cone-shaped gear blank rolling over a cutting tooth on a plane crown rack. The resulting impression on the plastic gear blank is the envelope of the cutting tooth. This impression and envelope thus form a conjugate tooth surface. Equations are presented for the locus of points on the tooth surface. The same procedures are then extended to simulate the generation of a spiral bevel gear. The corresponding governing equations are presented.

  13. Computer aided design of bevel gear tooth surfaces

    Chang, S. H.; Huston, R. L.; Coy, J. J.

    1989-01-01

    This paper presents a computer-aided design procedure for generating bevel gears. The development is based on examining a perfectly plastic, cone-shaped gear blank rolling over a cutting tooth on a plane crown rack. The resulting impression on the plastic gear blank is the envelope of the cutting tooth. This impression and envelope thus form a conjugate tooth surface. Equations are presented for the locus of points on the tooth surface. The same procedures are then extended to simulate the generation of a spiral bevel gear. The corresponding governing equations are presented.

  14. The theory and practice of worm gear drives

    Dudás, Ilés

    2005-01-01

    Worm gears are special gears that resemble screws, and can be used to drive other gears. Worm gears, enable two non-touching shafts in a machine to mesh (join) together. This publication, unique in that it combines both theoretical and practical design aspects, including the latest results of research and development, provides detailed treatment of the theory and production of worm drives, as well as the overarching subject of production geometry of helicoidal surfaces.Included are mathematical models for a number of practical applications; a description of dressing equipment r

  15. Molecular Dynamics Simulations of Laser Powered Carbon Nanotube Gears

    Srivastava, Deepak; Globus, Al; Han, Jie; Chancellor, Marisa K. (Technical Monitor)

    1997-01-01

    Dynamics of laser powered carbon nanotube gears is investigated by molecular dynamics simulations with Brenner's hydrocarbon potential. We find that when the frequency of the laser electric field is much less than the intrinsic frequency of the carbon nanotube, the tube exhibits an oscillatory pendulam behavior. However, a unidirectional rotation of the gear with oscillating frequency is observed under conditions of resonance between the laser field and intrinsic gear frequencies. The operating conditions for stable rotations of the nanotube gears, powered by laser electric fields are explored, in these simulations.

  16. Turbine Engine with Differential Gear Driven Fan and Compressor

    Suciu, Gabriel L. (Inventor); Pagluica, Gino J. (Inventor); Duong, Loc Quang (Inventor); Portlock, Lawrence E. (Inventor)

    2013-01-01

    A gas turbine engine provides a differential gear system coupling the turbine to the bypass fan and the compressor. In this manner, the power/speed split between the bypass fan and the compressor can be optimized under all conditions. In the example shown, the turbine drives a sun gear, which drives a planet carrier and a ring gear in a differential manner. One of the planet carrier and the ring gear is coupled to the bypass fan, while the other is coupled to the compressor.

  17. Design, Load Analysis and Optimization of Compound Epicyclic Gear Trains

    Syed Ibrahim Dilawer

    2013-01-01

    - Gears in the Epicyclic gear trains are one of the most critical components in the mechanical power transmission system in which failure of one gear will affect the whole transmission system, thus it is very necessary to determine the causes of failure in an attempt to reduce them. The different modes of failure of gears and their possible remedies to avoid the failure are mentioned in J.R. Davis (2005) [17], Khurmi & Gupta (2006) [19], P. Kannaiah (2006) [18] [20] as bending failure (load f...

  18. EFFECT OF GEAR WIDTH AND HELIX ANGLE ON FACTOR OF DYNAMIC LOAD OF DOUBLE CIRCULAR ARC HELICAL GEARING

    Wu Baolin

    2004-01-01

    Based on theory of mechanical dynamics, meshing characteristic as well as the dynamic model of double circular arc helical gearing, an analysis approach and a computer program have been developed for studying the state of dynamic load and factor of dynamic load of the gearing, the changing situation of dynamic load and dynamic load factor vs some affecting factors such as gear width, helix angle and accuracy grade etc are investigated. A series of conclusions are obtained: ①With the increasing in the values of gear width, the dynamic load factor appears slow decreasing tendency in most region of gear width. ② When the accuracy grades of the gearing are improved, the values of dynamic load factor decrease. ③ The value of dynamic load factor appears a decreasing tendency with the increasing of value of helix angle at the same ratio of critical rotational speed.

  19. MODEL PELAYANAN STROKE TERPADU DI RUMAH SAKIT ADI HUSADA UNDAAN WETAN SURABAYA

    Koosnadi Saputra

    2012-11-01

    Full Text Available Stroke or brain attack is basically brain dysfunction as the effect of disparity on vascular circulation of the brain that caused by various factors. The basic aspect of the brain are influenced by various factors. The basic physiology and psychology aspects of the stroke is essential to understand, especially the correlation to underlying diseases and psychological stress as a social trigger aspect phenomenon. Although stroke could occur at all ages, generally it attacks adult people, and its incidence is increasing at the older age groups. Considering doctor needs to propmtly recognize the symptoms of stroke including its problems, as to manage the problems and to prevent are the most important things to do. The Adi Husada Undaan Wetan Hospital of Surabaya has built the Pelayanan Stroke Terpadu (PST as a system to manage stroke patients which composed of a stroke team specialists who work in prompt responses, prompt treatments and prompt rehabilitation. The PST was developed based on experiences on stroke patient treatment during 12 year period (1 994-2006 in Adi Husada Hospital Surabaya and the data of computerized axial tomography comparing•year 1995 to 2006 (pre-programof the PST condition. Key words:

  20. Holmes-Adie syndrome, autoimmune hepatitis and celiac disease: A case report

    Timea Csak; Aniko Folhoffer; Andrea Horvath; Judit Halász; Csaba Diczházi; Zsuzsa Schaff; Ferenc Szalay

    2006-01-01

    A 35-year-old female patient presented with the following symptoms of Holmes-Adie syndrome: photophobia,enlargement of the left pupil unresponsive to light,Achilles areflexia. The pilocarpine test was positive. No tumor or other neurological abnormality was found. She had a 19-year history of autoimmune hepatitis. Flares up were observed following each 3 deliveries. At age of 31she presented with diarrhea and weight loss. Abdominal tumor was detected by ultrasound. The surgically removed tumor was histologically a benign mesenteric multicystic lymphangioma. Simultaneously, celiac disease was diagnosed. Gluten-free diet resulted in a significant improvement of celiac disease, but not of autoimmune hepatitis. Autonomic neuropathy was proven by standard cardiovascular tests. The patient was a homozygous carrier for HLA DQ2 antigen characteristic for celiac disease and heterozygous for HLA DR3 B8 frequent in autoimmune liver diseases. Our novel observation on association of Holmes-Adie syndrome with autoimmune hepatitis and celiac disease is suggestive for a common immunological background for all three entities present in a patient with mesenteric multicystic lymphangioma.

  1. 76 FR 50180 - Proposed Information Collection; Comment Request; Northwest Region Gear Identification Requirements

    2011-08-12

    ... Fishery Conservation and Management Act (MSA). The marking of fishing gear is also valuable in actions... Region Gear Identification Requirements AGENCY: National Oceanic and Atmospheric Administration (NOAA... management programs depends significantly on regulatory compliance. The requirements that fishing gear...

  2. The relative noise levels of parallel axis gear sets with various contact ratios and gear tooth forms

    Drago, Raymond J.; Lenski, Joseph W., Jr.; Spencer, Robert H.; Valco, Mark; Oswald, Fred B.

    1993-01-01

    The real noise reduction benefits which may be obtained through the use of one gear tooth form as compared to another is an important design parameter for any geared system, especially for helicopters in which both weight and reliability are very important factors. This paper describes the design and testing of nine sets of gears which are as identical as possible except for their basic tooth geometry. Noise measurements were made at various combinations of load and speed for each gear set so that direct comparisons could be made. The resultant data was analyzed so that valid conclusions could be drawn and interpreted for design use.

  3. Variable gearing in a biologically inspired pneumatic actuator array

    A fundamental feature of pennate muscles is that muscle fibers are oriented at an angle to the line of action and rotate as they shorten, becoming more oblique throughout a contraction. This change in fiber orientation (pennation angle) can amplify the shortening velocity of a fiber and increase output velocity of the muscle. The velocity advantage resulting from dynamic changes in pennation angle can be characterized as a gear ratio (muscle velocity/fiber velocity). A recent study has shown that a pennate muscle's gear ratio varies automatically depending on the load such that a muscle operates with a high gear during rapid contractions and low gear during forceful contractions. We examined whether this variable gearing behavior can be replicated in a pennate array of artificial muscles. We used McKibben type pneumatic actuators, which shorten in tension when filled with compressed gas. Similar to muscle fibers, the actuators expand radially during shortening, a feature thought to be a critical part of the variable gearing mechanism in pennate muscles. We arranged McKibben actuators in an array oriented to mimic a pennate muscle, and quantified the system's gear ratio during contraction against a range of loads. Video was used to measure the gear ratio during each contraction. We find that similar to pennate muscles, the gear ratio decreases significantly with increasing load and that variable gearing results from load-dependent variation in the amount of actuator rotation. These results support the idea that variable gearing in pennate muscles is mediated by difference is fiber rotation and the direction of muscle bulging. The behavior of our artificial muscle array also highlights the potential benefits of bio-inspired architectures in artificial muscle arrays, including the ability to vary force and speed automatically in response to variable loading conditions. (paper)

  4. Glow-discharge nitriding of gears

    The method of glow-discharge nitriding of gear parts made of 30Kh2NMFA steel is introduced. The diffusion saturation is carried out in the atmosphere of dissociated ammonia at the temperature of 520-540 deg C and 200-800 Pa pressure for 16-40 h depending on the required thickness of the nitrided layer (0.2-0.5 mm). The structure of the nitrided metal is a layer of nitride compounds of the Fe4N type and diffusion zone enriched with nitrides. Glow-discharge nitrided parts with 600-650 HV strength retain certain wear resistance and fatigue strength as compared with gas nitriding

  5. Topological Expression Model of Satellite Gear Mechanism

    Yang Ping

    2005-01-01

    By investigation of the topological characteristics of the kinematic structure of Satellite Gear Mechanism (SGM) with graph theory, the graph model of SGM is analyzed, and a topological expression model between input and output of SGM is established based on systematic design point. Meanwhile, the mathematical expression for SGM is deduced by integrating matrix theory and graph theory; thus, the topological characteristics of the kinematic structure of SGM can be converted into a matrix model, and the topological design problem of SGM into a matrix operation problem. In addition, a brief discussion about the measures for identification of isomorphism of the graph mode is made.

  6. Nonlinear parametrically excited vibration and active control of gear pair system with time-varying characteristic

    Liu, Shuang; Wang, Jin-Jin; Liu, Jin-Jie; Li, Ya-Qian

    2015-10-01

    In the present work, we investigate the nonlinear parametrically excited vibration and active control of a gear pair system involving backlash, time-varying meshing stiffness and static transmission error. Firstly, a gear pair model is established in a strongly nonlinear form, and its nonlinear vibration characteristics are systematically investigated through different approaches. Several complicated phenomena such as period doubling bifurcation, anti period doubling bifurcation and chaos can be observed under the internal parametric excitation. Then, an active compensation controller is designed to suppress the vibration, including the chaos. Finally, the effectiveness of the proposed controller is verified numerically. Project supported by the National Natural Science Foundation of China (Grant No. 61104040), the Natural Science Foundation of Hebei Province, China (Grant No. E2012203090), and the University Innovation Team of Hebei Province Leading Talent Cultivation Project, China (Grant No. LJRC013).

  7. 14 CFR 25.477 - Landing gear arrangement.

    2010-01-01

    ... 14 Aeronautics and Space 1 2010-01-01 2010-01-01 false Landing gear arrangement. 25.477 Section 25.477 Aeronautics and Space FEDERAL AVIATION ADMINISTRATION, DEPARTMENT OF TRANSPORTATION AIRCRAFT AIRWORTHINESS STANDARDS: TRANSPORT CATEGORY AIRPLANES Structure Ground Loads § 25.477 Landing gear...

  8. Potential for Landing Gear Noise Reduction on Advanced Aircraft Configurations

    Thomas, Russell H.; Nickol, Craig L.; Burley, Casey L.; Guo, Yueping

    2016-01-01

    The potential of significantly reducing aircraft landing gear noise is explored for aircraft configurations with engines installed above the wings or the fuselage. An innovative concept is studied that does not alter the main gear assembly itself but does shorten the main strut and integrates the gear in pods whose interior surfaces are treated with acoustic liner. The concept is meant to achieve maximum noise reduction so that main landing gears can be eliminated as a major source of airframe noise. By applying this concept to an aircraft configuration with 2025 entry-into-service technology levels, it is shown that compared to noise levels of current technology, the main gear noise can be reduced by 10 EPNL dB, bringing the main gear noise close to a floor established by other components such as the nose gear. The assessment of the noise reduction potential accounts for design features for the advanced aircraft configuration and includes the effects of local flow velocity in and around the pods, gear noise reflection from the airframe, and reflection and attenuation from acoustic liner treatment on pod surfaces and doors. A technical roadmap for maturing this concept is discussed, and the possible drag increase at cruise due to the addition of the pods is identified as a challenge, which needs to be quantified and minimized possibly with the combination of detailed design and application of drag reduction technologies.

  9. 33 CFR 164.39 - Steering gear: Foreign tankers.

    2010-07-01

    ... 33 Navigation and Navigable Waters 2 2010-07-01 2010-07-01 false Steering gear: Foreign tankers... (CONTINUED) PORTS AND WATERWAYS SAFETY NAVIGATION SAFETY REGULATIONS § 164.39 Steering gear: Foreign tankers. (a) This section applies to each foreign tanker of 10,000 gross tons or more, except a public...

  10. 50 CFR 600.510 - Gear avoidance and disposal.

    2010-10-01

    ... fishery in which the FFV is engaged. (b) Gear conflicts. The operator of each FFV that is involved in a... 50 Wildlife and Fisheries 8 2010-10-01 2010-10-01 false Gear avoidance and disposal. 600.510 Section 600.510 Wildlife and Fisheries FISHERY CONSERVATION AND MANAGEMENT, NATIONAL OCEANIC...

  11. 50 CFR 648.296 - Gear restricted areas.

    2010-10-01

    ... Tilefish Fishery § 648.296 Gear restricted areas. No vessel of the United States may fish with bottom... 50 Wildlife and Fisheries 8 2010-10-01 2010-10-01 false Gear restricted areas. 648.296 Section 648.296 Wildlife and Fisheries FISHERY CONSERVATION AND MANAGEMENT, NATIONAL OCEANIC AND...

  12. 50 CFR 648.264 - Gear requirements/restrictions.

    2010-10-01

    ... Measures for the Atlantic Deep-Sea Red Crab Fishery § 648.264 Gear requirements/restrictions. (a) Limited... 50 Wildlife and Fisheries 8 2010-10-01 2010-10-01 false Gear requirements/restrictions. 648.264 Section 648.264 Wildlife and Fisheries FISHERY CONSERVATION AND MANAGEMENT, NATIONAL OCEANIC...

  13. 50 CFR 648.234 - Gear restrictions. [Reserved

    2010-10-01

    ... Fishery § 648.234 Gear restrictions. ... 50 Wildlife and Fisheries 8 2010-10-01 2010-10-01 false Gear restrictions. 648.234 Section 648.234 Wildlife and Fisheries FISHERY CONSERVATION AND MANAGEMENT, NATIONAL OCEANIC AND ATMOSPHERIC...

  14. Nonlinear Vibroimpact Characteristics of a Planetary Gear Transmission System

    Jianxing Zhou

    2016-01-01

    Full Text Available In order to research the vibroimpact characteristics of a planetary gear transmission system under high speed and lightly loaded conditions, a new modeling method is proposed. In the modeling process, linear spring was used to simulate gear mesh elasticity under heavy load cases, and Hertz contact theory was used to calculate the contact force of gear pair under light load cases. Then, effects of the working conditions on the system vibroimpact characteristics are analyzed. The results show that, with input speed growing, the mesh force produced obvious fluctuations on the resonance frequencies of the sun gear and carrier torsion vibration, ring gear’s transverse vibration under the heavy load. Under light load condition, the collision vibration occurs in the gear pair; the changing trend of the contact force shows strongly nonlinear characteristics. The time of mesh-apart in gears pair decreases gradually as the load is increased; until it reaches collision vibration threshold value, the gear pair is no longer mesh-apart. With increasing of the input speed, the time of mesh-apart is decreased gradually; the fluctuation amplitude of contact force shows a linearly increasing trend. The study provides useful theoretical guideline for planetary gear transmission low-noise design.

  15. Analysis of Pitch Gear Deterioration using Indicators

    Nielsen, Jannie Jessen; Sørensen, John Dalsgaard

    This work concerns a case study in the context of risk-based operation and maintenance of offshore wind turbines. For turbines with electrical pitch systems, deterioration can generally be observed at the pitch gear teeth; especially at the point the blades are located during normal production. T...... SCADA system, it became obvious that seasonal changes in the temperature were the primary cause of the decrease. A model was established to remove the effect of the explained variation, and see if deterioration can be detected in the peak torque.......This work concerns a case study in the context of risk-based operation and maintenance of offshore wind turbines. For turbines with electrical pitch systems, deterioration can generally be observed at the pitch gear teeth; especially at the point the blades are located during normal production....... This deterioration is expected to cause larger loads, because increased play causes dynamic loads. At some point, the increased loads can be expected to cause a failure somewhere in the pitch system. If the loads increase with the size of the damage, the loads can be used as indicators of the size of...

  16. Hybrid foundry patterns of bevel gears

    Budzik G.

    2007-01-01

    Full Text Available Possibilities of making hybrid foundry patterns of bevel gears for investment casting process are presented. Rapid prototyping of gears with complex tooth forms is possible with the use of modern methods. One of such methods is the stereo-lithography, where a pattern is obtained as a result of resin curing with laser beam. Patterns of that type are applicable in precision casting. Removing of stereo-lithographic pattern from foundry mould requires use of high temperatures. Resin burning would generate significant amounts of harmful gases. In case of a solid stereo-lithographic pattern, the pressure created during gas burning may cause the mould to crack. A gas volume reduction may be achieved by using patterns of honeycomb structure. However, this technique causes a significant worsening of accuracy of stereo-lithographic patterns in respect of their dimensions and shape. In cooperation with WSK PZL Rzeszów, the Machine Design Department of Rzeszow University of Technology carried out research on the design of hybrid stereo-lithographic patterns. Hybrid pattern consists of a section made by stereo-lithographic process and a section made of casting wax. The latter material is used for stereo-lithographic pattern filling and for mould gating system. The hybrid pattern process consists of two stages: wax melting and then the burn-out of stereolithographic pattern. Use of hybrid patterns reduces the costs of production of stereolithographic patterns. High dimensional accuracy remains preserved in this process.

  17. The NASA landing gear test airplane

    Carter, John F.; Nagy, Christopher J.

    1995-01-01

    A tire and landing gear test facility has been developed and incorporated into a Convair 990 aircraft. The system can simulate tire vertical load profiles to 250,000 lb, sideslip angles to 15 degrees, and wheel braking on actual runways. Onboard computers control the preprogrammed test profiles through a feedback loop and also record three axis loads, tire slip angle, and tire condition. The aircraft to date has provided tire force and wear data for the Shuttle Orbiter tire on three different runways and at east and west coast landing sites. This report discusses the role of this facility in complementing existing ground tire and landing gear test facilities, and how this facility can simultaneously simulate the vertical load, tire slip, velocity, and surface for an entire aircraft landing. A description is given of the aircraft as well as the test system. An example of a typical test sequence is presented. Data collection and reduction from this facility are discussed, as well as accuracies of calculated parameters. Validation of the facility through ground and flight tests is presented. Tests to date have shown that this facility can operate at remote sites and gather complete data sets of load, slip, and velocity on actual runway surfaces. The ground and flight tests have led to a successful validation of this test facility.

  18. Composite skid landing gear design investigation

    Shrotri, Kshitij

    A Composite Skid Landing Gear Design investigation has been conducted. Limit Drop Test as per Federal Aviation Regulations (FAR) Part 27.725 and Crash test as per MIL STD 1290A (AV) were simulated using ABAQUS to evaluate performance of multiple composite fiber-matrix systems. Load factor developed during multiple landing scenarios and energy dissipated during crash were computed. Strength and stiffness based constraints were imposed. Tsai-Wu and LaRC04 physics based failure criteria were used for limit loads. Hashin's damage initiation criteria with Davila-Camanho's energy based damage evolution damage evolution law were used for crash. Initial results indicate that all single-composite skid landing gear may no be feasible due to strength concerns in the cross member bends. Hybridization of multiple composites with elasto-plastic aluminum 7075 showed proof of strength under limit loads. Laminate tailoring for load factor optimization under limit loads was done by parameterization of a single variable fiber orientation angle for multiple laminate families. Tsai-Wu failure criterion was used to impose strength contraints. A quasi-isotropic N = 4 (pi/4) 48 ply IM7/8552 laminate was shown to be the optimal solution with a load failure will be initiated as matrix cracking under compression and fiber kinking under in-plane shear and longitudinal compression. All failures under limit loads being reported in the metal-composite hybrid joint region, the joint was simulated by adhesive bonding and filament winding, separately. Simply adhesive bonding the metal and composite regions does not meet strength requirements. A filament wound metal-composite joint shows proof of strength. Filament wound bolted metal-composite joint shows proof of strength. Filament wound composite bolted to metal cross member radii is the final joining methodology. Finally, crash analysis was conducted as per requirements from MIL STD 1290A (AV). Crash at 42 ft/sec with 1 design gross weight (DGW

  19. Actively Controlled Landing Gear for Aircraft Vibration Reduction

    Horta, Lucas G.; Daugherty, Robert H.; Martinson, Veloria J.

    1999-01-01

    Concepts for long-range air travel are characterized by airframe designs with long, slender, relatively flexible fuselages. One aspect often overlooked is ground induced vibration of these aircraft. This paper presents an analytical and experimental study of reducing ground-induced aircraft vibration loads using actively controlled landing gears. A facility has been developed to test various active landing gear control concepts and their performance. The facility uses a NAVY A6-intruder landing gear fitted with an auxiliary hydraulic supply electronically controlled by servo valves. An analytical model of the gear is presented including modifications to actuate the gear externally and test data is used to validate the model. The control design is described and closed-loop test and analysis comparisons are presented.

  20. Dynamic Analysis of Geared Rotors by Finite Elements

    Kahraman, A.; Ozguven, H. Nevzat; Houser, D. R.; Zakrajsek, J. J.

    1992-01-01

    A finite element model of a geared rotor system on flexible bearings has been developed. The model includes the rotary inertia of on shaft elements, the axial loading on shafts, flexibility and damping of bearings, material damping of shafts and the stiffness and the damping of gear mesh. The coupling between the torsional and transverse vibrations of gears were considered in the model. A constant mesh stiffness was assumed. The analysis procedure can be used for forced vibration analysis geared rotors by calculating the critical speeds and determining the response of any point on the shafts to mass unbalances, geometric eccentricities of gears, and displacement transmission error excitation at the mesh point. The dynamic mesh forces due to these excitations can also be calculated. The model has been applied to several systems for the demonstration of its accuracy and for studying the effect of bearing compliances on system dynamics.

  1. On-line tribochemical strengthening of gear surface

    2001-01-01

    It has been found that under favorable friction conditions some antiwear elements inlubricating additives can permeate into subsurface of metal which can strengthens the friction sur-faces and improves anti-wear capacity of frication pairs. It is in many ways similar to chemical heattreatment. A new concept, technology of on-line strengthening, was logically put forward. Based oncurrent gear surface treatment technology, the on-line strengthen of gear surface is proposed. Itsdesign method is established. Based on it, the on-line strengthen of gear is achieved on CL-100gear test machine. A new method is put forward for strengthen treatment of gear surface. Andthree kinds of surface film were suggested.

  2. Design of stimulation optimized planetary gears; Entwurf anregungsoptimierter Planetengetriebe

    Paples, Jennifer; Vill, Dietmar [Bochum Univ. (Germany). Lehrstuhl fuer Industrie- und Fahrzeugantriebstechnik

    2013-06-01

    Planetary gears are characterized by their high power density combined with their compactness. To take full advantage of these benefits a uniform distribution of the load on the individual planet gears has to be achieved. In planetary gears the chronology of the meshing of the teeth involved depends only on the macro-geometry of the gears, namely the number of teeth and the angular pitch of the planet carrier. The interaction between these meshing teeth provides an additional parameter for excitation because of their phase delayed stiffnesses, which counteracts this uniform distribution. With the aid of the variation of toothing parameters, such as tooth height or shift factors, which are influenced by the design engineer, the stiffnesses in the meshing between sun and planet and between planet and ring gear can be balanced at its best to provide low vibration. (orig.)

  3. A GPU-accelerated semi-implicit ADI method for incompressible and compressible Navier-Stokes equations

    Ha, Sanghyun; You, Donghyun

    2015-11-01

    Utility of the computational power of Graphics Processing Units (GPUs) is elaborated for solutions of both incompressible and compressible Navier-Stokes equations. A semi-implicit ADI finite-volume method for integration of the incompressible and compressible Navier-Stokes equations, which are discretized on a structured arbitrary grid, is parallelized for GPU computations using CUDA (Compute Unified Device Architecture). In the semi-implicit ADI finite-volume method, the nonlinear convection terms and the linear diffusion terms are integrated in time using a combination of an explicit scheme and an ADI scheme. Inversion of multiple tri-diagonal matrices is found to be the major challenge in GPU computations of the present method. Some of the algorithms for solving tri-diagonal matrices on GPUs are evaluated and optimized for GPU-acceleration of the present semi-implicit ADI computations of incompressible and compressible Navier-Stokes equations. Supported by the Basic Science Research Program through the National Research Foundation of Korea (NRF) funded by the Ministry of Science, ICT and Future Planning Grant NRF-2014R1A2A1A11049599.

  4. Reliability Based Optimum Design of a Gear Box

    D.Madhusekhar

    2014-10-01

    Full Text Available The gear box represents an important mechanical sub system. In machine tools, the propose of a gear box is to provide a series of useful output speeds so that the machining operation can be carried out at its most optimum operating conditions high spindle speeds with low feed rate for roughing operations. An important aspect in the design of machine tool transmission is to keep the cost and volume of the gear box to a minimum. The probabilistic approach to design has been considered to be more rational compared to the conventional design approach based on the factor of safety. The existence of uncertainties in either engineering simulations or manufacturing processes calls for a reliability-based design optimization (RBDO model for robust and cost-effective designs. In the present work a three shaft four speed gear box is designed using reliability principles. For the specified reliability of the system (Gear box, component reliability (Gear pair is calculated by considering the system as a series system. Design is considered to be safe and adequate if the probability of failure of gear box is less than or equal to a specified quantity in each of the two failure modes. A FORTRAN program has been developed to calculate the mean values of face widths of gears for the minimum mass of gear box. By changing the probability of failure of system variations in the face widths are studied. The reliability based optimum design results are compared with those obtained by deterministic optimum design. The minimum mass of the gear box is increase as the specified values of the reliability is increased.

  5. An arithmetic for core physics real-time simulation based on ADI

    In the core physics real-time simulation, the traditional Alternative Direction Implicit (ADI) method for solving the neutron diffusion equations requires too much calculation time to meet the real-time demand. In this paper, one fuel assembly is considered as one mesh-cell in radial direction to reduce the calculation time; the adjusting factor is added to the finite difference equations to improve the calculation accuracy. The calculation accuracy and speed are tested by its application to the core physics real-time simulation for Qin Shan NPP PHASE Ⅱ. The simulation result shows that this approach is applicable for the core physics real-time simulation. With online correction technology, the online real time simulation is accomplished. (authors)

  6. Classifying Autism Spectrum Disorders by ADI-R: Subtypes or Severity Gradient?

    Cholemkery, Hannah; Medda, Juliane; Lempp, Thomas; Freitag, Christine M

    2016-07-01

    To reduce phenotypic heterogeneity of Autism spectrum disorders (ASD) and add to the current diagnostic discussion this study aimed at identifying clinically meaningful ASD subgroups. Cluster analyses were used to describe empirically derived groups based on the Autism Diagnostic Interview-revised (ADI-R) in a large sample of n = 463 individuals with ASD aged 3-21. Three clusters were observed. Most severely affected individuals regarding all core symptoms were allocated to cluster 2. Cluster 3 comprised moderate symptom severity of social communication impairments (SCI) and less stereotyped repetitive behavior (RRB). Minor SCI and relatively more RRB characterized cluster 1. This study offers support for both, a symptom profile, and a gradient model of ASD within the spectrum due to the sample included. PMID:26956715

  7. Shared Memory Parallelization of an Implicit ADI-type CFD Code

    Hauser, Th.; Huang, P. G.

    1999-01-01

    A parallelization study designed for ADI-type algorithms is presented using the OpenMP specification for shared-memory multiprocessor programming. Details of optimizations specifically addressed to cache-based computer architectures are described and performance measurements for the single and multiprocessor implementation are summarized. The paper demonstrates that optimization of memory access on a cache-based computer architecture controls the performance of the computational algorithm. A hybrid MPI/OpenMP approach is proposed for clusters of shared memory machines to further enhance the parallel performance. The method is applied to develop a new LES/DNS code, named LESTool. A preliminary DNS calculation of a fully developed channel flow at a Reynolds number of 180, Re(sub tau) = 180, has shown good agreement with existing data.

  8. Chemical-specific adjustment factors (inter-species toxicokinetics) to establish the ADI for steviol glycosides.

    Roberts, Ashley; Lynch, Barry; Rogerson, Rebecca; Renwick, Andrew; Kern, Hua; Coffee, Matthew; Cuellar-Kingston, Nicole; Eapen, Alex; Crincoli, Christine; Pugh, George; Bhusari, Sachin; Purkayastha, Sidd; Carakostas, Michael

    2016-08-01

    The acceptable daily intake (ADI) of commercially available steviol glycosides is currently 0-4 mg/kg body weight (bw)/day, based on application of a 100-fold uncertainty factor to a no-observed-adverse-effect-level value from a chronic rat study. Within the 100-fold uncertainty factor is a 10-fold uncertainty factor to account for inter-species differences in toxicokinetics (4-fold) and toxicodynamics (2.5-fold). Single dose pharmacokinetics of stevioside were studied in rats (40 and 1000 mg/kg bw) and in male human subjects (40 mg/kg bw) to generate a chemical-specific, inter-species toxicokinetic adjustment factor. Tmax values for steviol were at ∼8 and ∼20 h after administration in rats and humans, respectively. Peak concentrations of steviol were similar in rats and humans, while steviol glucuronide concentrations were significantly higher in humans. Glucuronidation in rats was not saturated over the dose range 40-1000 mg/kg bw. The AUC0-last for steviol was approximately 2.8-fold greater in humans compared to rats. Chemical-specific adjustment factors for extrapolating toxicokinetics from rat to human of 1 and 2.8 were established based on Cmax and AUC0-last data respectively. Because these factors are lower than the default value of 4.0, a higher ADI for steviol glycosides of between 6 and 16 mg/kg bw/d is justified. PMID:27181453

  9. Systems design of advanced gear steels

    Wise, John Patrick

    A new generation of Ni-Co secondary hardening gear steels has been developed using a systems approach. These high toughness ultrahigh-strength martensitic steels show great promise for demanding gear applications. Quantitative science-based modeling was used to create prototype alloys of superior strength and fatigue resistance over conventional steels. Carburizing and strengthening models were developed to relate processing parameters to microstructure and microstructure to strength. The failure of the DICTRA software to accurately predict the carburizing behavior of Ni-Co steels led to a series of experiments to refine its kinetic database. New carbon diffusivities were calculated from the concentration gradients of carburized model alloys, resulting in a significant improvement of simulation accuracy. A structure/property model was created to equate the strength of a secondary hardening steel to the sum of the effects of solid solution, precipitates, dislocation density, and the substructure of the lath martensite matrix. The strengthening model was subsequently combined with the carburizing simulations to predict the hardness gradient in a case-hardened alloy based upon initial carburizing conditions. In addition, existing precipitation theory was used in conjunction with the microstructure/strength relationship to simulate the evolution of material hardness during secondary hardening. The creation of three prototype gear steels began with the use of the strengthening model to establish the carbon and alloying element contents required to reach the core and case hardness objectives of 50 and 70 HRC respectively. The design approach also included the establishment of proper transformation and solution temperatures and the maximization of the efficiency of the Msb2C carbide strengthening dispersion. The core hardnesses of the C3-A and B prototypes significantly exceeded the design goal. A reduction in core carbon content from 0.16 to 0.12 weight percent was

  10. Identification of a Non-Linear Landing Gear Model Using Nature-Inspired Optimization

    Felipe A.C. Viana

    2008-01-01

    Full Text Available This work deals with the application of a nature-inspired optimization technique to solve an inverse problem represented by the identification of an aircraft landing gear model. The model is described in terms of the landing gear geometry, internal volumes and areas, shock absorber travel, tire type, and gas and oil characteristics of the shock absorber. The solution to this inverse problem can be obtained by using classical gradient-based optimization methods. However, this is a difficult task due to the existence of local minima in the design space and the requirement of an initial guess. These aspects have motivated the authors to explore a nature-inspired approach using a method known as LifeCycle Model. In the present formulation two nature-based methods, namely the Genetic Algorithms and the Particle Swarm Optimization were used. An optimization problem is formulated in which the objective function represents the difference between the measured characteristics of the system and its model counterpart. The polytropic coefficient of the gas and the damping parameter of the shock absorber are assumed as being unknown: they are considered as design variables. As an illustration, experimental drop test data, obtained under zero horizontal speed, were used in the non-linear landing gear model updating of a small aircraft.

  11. Analysis of Pitch Gear Deterioration using Indicators

    Nielsen, Jannie Jessen; Sørensen, John Dalsgaard

    2011-01-01

    supported by results from a measurement campaign where measurements are available both before and after maintenance was performed. The loads dramatically decreased after the maintenance. However, after a few more months of measurements, and by including data from the SCADA system, it became obvious that......This work concerns a case study in the context of risk-based operation and maintenance of offshore wind turbines. For wind turbines with electrical pitch systems, deterioration can generally be observed at the pitch gear teeth; especially at the point where the blades are located during normal...... production. This deterioration is expected to cause larger loads, because increased play causes dynamic loads. At some point, the increased loads can be expected to cause failure somewhere in the pitch system. If the loads increase with the size of the damage, the loads can be used as indicators of the size...

  12. 飞利浦GoGear MUSE

    2010-01-01

    当价格成为选择苹果最痛苦的纠结时,其实还有一个腕级的品牌可供选择——飞利浦。从2008年进入国内,已经有包括GoGearSA28、Mix、SA075等在内的一大批数码播放产品脱颖而出。个性与差异化是飞利浦GoGear系列播放器的特质。关于MUSE,早在今年4月的国内经销商大会上已经被躁光,并被飞利浦官方评价为“最牛使用体验”。真相是什么呢?。

  13. Increased Fidelity in Prediction Methods For Landing Gear Noise

    Lopes, Leonard V.; Brentner, Kenneth S.; Morris, Philip J.; Lockhard, David P.

    2006-01-01

    An aeroacoustic prediction scheme has been developed for landing gear noise. The method is designed to handle the complex landing gear geometry of current and future aircraft. The gear is represented by a collection of subassemblies and simple components that are modeled using acoustic elements. These acoustic elements are generic, but generate noise representative of the physical components on a landing gear. The method sums the noise radiation from each component of the undercarriage in isolation accounting for interference with adjacent components through an estimate of the local upstream and downstream flows and turbulence intensities. The acoustic calculations are made in the code LGMAP, which computes the sound pressure levels at various observer locations. The method can calculate the noise from the undercarriage in isolation or installed on an aircraft for both main and nose landing gear. Comparisons with wind tunnel and flight data are used to initially calibrate the method, then it may be used to predict the noise of any landing gear. In this paper, noise predictions are compared with wind tunnel data for model landing gears of various scales and levels of fidelity, as well as with flight data on fullscale undercarriages. The present agreement between the calculations and measurements suggests the method has promise for future application in the prediction of airframe noise.

  14. A study on the automated design system for gear

    A computer aided design system for spur, helical, bevel and worm gears by using AutoCAD system and its AutoLISP computer language was newly developed in this study. Two methods are available for a designer to draw a gear. The first method needs the gear design parameters such as pressure, module, number of tooth, shaft angle, velocity, materials, etc. When the gear design parameters are inputted, a gear is drawn in AutoCAD system and maximum allowable power and shaft diameter are calculated additionally. The second method calculates all dimensions and gear design parameters to draw a gear when the information such as transmission, reduction ratio, rpm, materials and pressure are inputted. The system includes four programs. Each program is composed of a data input module, a database module, a strength calculation module, a drawing module, a text module and a drawing edit module. In conclusion, the CAD system would be widely used in companies to find the geometric data and manufacturing course

  15. DESIGN OF NONCIRCULAR GEARS WITH DISCONTINUOUS PITCH CURVE

    ZHANG Rui; WU Xutang

    2006-01-01

    When the noncircular gear pair is applied to the continuously variable transmission (CVT)with gear, the transmission ratio function is discontinuous. In accordance with this unique characteristic, a new approach to design and analyze noncircular gears with discontinuous pitch curve is proposed. The design courses of various noncircular gear pairs with discontinuous pitch curve are unified based on the numerical algorithm of spline fitting and "fairing boundary condition".According to the particularity of discontinuous pitch curve, the rules and procedures for teeth distribution are recommended. It is explained in detail why the undercut is formed and how to manage the undercut based on meshing principle. In addition, the calculation formulas for each tooth profile segment are also derived. If the tooth profile data are calculated, the measurement and the incision process for noncircular gear can be conducted and the CAD simulation can be achieved easily. To ensure the continuity of the transmission, the transmission interference of the tooth which is located at ratio of gear pair is obtained. The case study shows that this approach is successful and opens up a new way for the design ofnoncircular gear.

  16. Evaluation of Gear Condition Indicator Performance on Rotorcraft Fleet

    Antolick, Lance J.; Branning, Jeremy S.; Wade, Daniel R.; Dempsey, Paula J.

    2010-01-01

    The U.S. Army is currently expanding its fleet of Health Usage Monitoring Systems (HUMS) equipped aircraft at significant rates, to now include over 1,000 rotorcraft. Two different on-board HUMS, the Honeywell Modern Signal Processing Unit (MSPU) and the Goodrich Integrated Vehicle Health Management System (IVHMS), are collecting vibration health data on aircraft that include the Apache, Blackhawk, Chinook, and Kiowa Warrior. The objective of this paper is to recommend the most effective gear condition indicators for fleet use based on both a theoretical foundation and field data. Gear diagnostics with better performance will be recommended based on both a theoretical foundation and results of in-fleet use. In order to evaluate the gear condition indicator performance on rotorcraft fleets, results of more than five years of health monitoring for gear faults in the entire HUMS equipped Army helicopter fleet will be presented. More than ten examples of gear faults indicated by the gear CI have been compiled and each reviewed for accuracy. False alarms indications will also be discussed. Performance data from test rigs and seeded fault tests will also be presented. The results of the fleet analysis will be discussed, and a performance metric assigned to each of the competing algorithms. Gear fault diagnostic algorithms that are compliant with ADS-79A will be recommended for future use and development. The performance of gear algorithms used in the commercial units and the effectiveness of the gear CI as a fault identifier will be assessed using the criteria outlined in the standards in ADS-79A-HDBK, an Army handbook that outlines the conversion from Reliability Centered Maintenance to the On-Condition status of Condition Based Maintenance.

  17. 14 CFR 27.501 - Ground loading conditions: landing gear with skids.

    2010-01-01

    ... 14 Aeronautics and Space 1 2010-01-01 2010-01-01 false Ground loading conditions: landing gear... § 27.501 Ground loading conditions: landing gear with skids. (a) General. Rotorcraft with landing gear...) The gear in its most critically deflected position for the landing condition being considered; and...

  18. 14 CFR 29.501 - Ground loading conditions: landing gear with skids.

    2010-01-01

    ... 14 Aeronautics and Space 1 2010-01-01 2010-01-01 false Ground loading conditions: landing gear... § 29.501 Ground loading conditions: landing gear with skids. (a) General. Rotorcraft with landing gear...) The gear in its most critically deflected position for the landing condition being considered; and...

  19. 50 CFR Table 19 to Part 679 - Seabird Avoidance Gear Codes

    2010-10-01

    ... 50 Wildlife and Fisheries 9 2010-10-01 2010-10-01 false Seabird Avoidance Gear Codes 19 Table 19... ALASKA Pt. 679, Table 19 Table 19 to Part 679—Seabird Avoidance Gear Codes VESSEL LOGBOOK CODE SEABIRD AVOIDANCE GEAR OR METHOD. 1 Paired Streamer Lines: Used during deployment of hook-and-line gear to...

  20. 46 CFR 97.37-33 - Instructions for changing steering gear.

    2010-10-01

    ... 46 Shipping 4 2010-10-01 2010-10-01 false Instructions for changing steering gear. 97.37-33... steering gear. (a) Instructions in at least 1/2 inch letters and figures shall be posted in the steering... gear. Each clutch, gear, wheel, lever, valve, or switch which is used during the changeover shall...

  1. 50 CFR 660.213 - Fixed gear fishery-recordkeeping and reporting.

    2010-10-01

    ... 50 Wildlife and Fisheries 9 2010-10-01 2010-10-01 false Fixed gear fishery-recordkeeping and... West Coast Groundfish-Limited Entry Fixed Gear Fisheries § 660.213 Fixed gear fishery—recordkeeping and..., apply to limited entry fixed gear fishery vessels. (b) Declaration reports for limited entry fixed...

  2. 50 CFR 660.230 - Fixed gear fishery-management measures.

    2010-10-01

    ... 50 Wildlife and Fisheries 9 2010-10-01 2010-10-01 false Fixed gear fishery-management measures... West Coast Groundfish-Limited Entry Fixed Gear Fisheries § 660.230 Fixed gear fishery-management... apply to vessels participating in the limited entry groundfish fixed gear fishery and may not...

  3. If the Gear Fits, Spin It!: Embodied Education and in-Game Assessments

    Johnson-Glenberg, M.C.; Birchfield, D.; Megowan-Romanowicz, C.; Snow, E.L.

    2015-01-01

    Two embodied gears games were created. Better learners should use fewer gear switches to reflect their knowledge. Twenty–three 7th graders, playing as dyads, used gestures to manipulate virtual gears. The Kinect sensor tracked arm-spinning movements and switched gear diameters. Knowledge tests were

  4. Catching large herring larvae: Gear applicability and larval distribution

    Munk, Peter

    1988-01-01

    given to the influence of gear speed on catching effectiveness. An additional objective was to investigate larval distributional patterns of potential importance to sampling strategy. Gear speed had a pronounced influence on the efficiency of the IKMT. Catches per unit volume filtered decreased to one...... third when speed was increased by one knot. The efficiency of the MIK did not change in the speed range investigated, and this gear was in every case more efficient than the IKMT. Larvae were found to be patchily distributed at the scale of sampling, and the degree of patchiness did not increase when...

  5. ARTIFICIAL NEURAL NETWORKS BASED GEARS MATERIAL SELECTION HYBRID INTELLIGENT SYSTEM

    X.C. Li; W.X. Zhu; G. Chen; D.S. Mei; J. Zhang; K.M. Chen

    2003-01-01

    An artificial neural networks(ANNs) based gear material selection hybrid intelligent system is established by analyzing the individual advantages and weakness of expert system (ES) and ANNs and the applications in material select of them. The system mainly consists of tow parts: ES and ANNs. By being trained with much data samples,the back propagation (BP) ANN gets the knowledge of gear materials selection, and is able to inference according to user input. The system realizes the complementing of ANNs and ES. Using this system, engineers without materials selection experience can conveniently deal with gear materials selection.

  6. Computer Synthesis Approaches of Hyperboloid Gear Drives with Linear Contact

    Abadjiev Valentin

    2014-09-01

    Full Text Available The computer design has improved forming different type software for scientific researches in the field of gearing theory as well as performing an adequate scientific support of the gear drives manufacture. Here are attached computer programs that are based on mathematical models as a result of scientific researches. The modern gear transmissions require the construction of new mathematical approaches to their geometric, technological and strength analysis. The process of optimization, synthesis and design is based on adequate iteration procedures to find out an optimal solution by varying definite parameters.

  7. Engagement of Metal Debris into a Gear Mesh

    Handschuh, Robert F.; Krantz, Timothy L.

    2010-01-01

    A series of bench top experiments was conducted to determine the effects of metallic debris being dragged through meshing gear teeth. A test rig that is typically used to conduct contact fatigue experiments was used for these tests. Several sizes of drill material, shim stock, and pieces of gear teeth were introduced and then driven through the meshing region. The level of torque required to drive the "chip" through the gear mesh was measured. From the data gathered, chip size sufficient to jam the mechanism can be determined.

  8. Epicyclic Gear Train Solution Techniques with Application to Tandem Bicycling

    Corey, Christopher A.

    2003-01-01

    This thesis presents a unification of kinematic and force-based methods for the design and analysis of planetary gear trains along with a discussion of potential applications in tandem biking. Specifically, this thesis will provide a simple solution technique for the general case of a two-degree of freedom (2DOF) planetary gear train along with new graphical design aids. It will also address the use of epicyclic gear trains as a power coupling in a tandem bike. In the current literature, p...

  9. Technology Innovation of Power Transmission Gearing in Aviation

    Handschuh, Robert F.

    2009-01-01

    An overview of rotary wing evolution and innovations over the last 20 years was presented. This overview is provided from a drive system perspective. Examples of technology innovations that have changed and advanced drive systems of rotary wing vehicles will be provided. These innovations include full 6-axis CNC gear manufacture, face gear development to aerospace standards, health and usage monitoring, and gear geometry and bearing improvements. Also, an overview of current state-of-the-art activities being conducted at NASA Glenn is presented with a short look to fixed and rotary wing aircraft and systems needed for the future.

  10. A study on the worm gear deficiencies in MOV actuators

    An MOV(Motor Operated Valve) is a valve system which is operated by an electric motor. The actuator in an MOV is composed of a motor, a worm, a worm gear and bearings. Faults of these components affect the performance of MOVs. Therefore detecting the faults of components before their break will contribute greatly to the safe operation of power plants. However it is very difficult to inspect the components without disassembly. In this paper, we diagnose the worm gear by examining motor torque signature, since the condition of the worm gear is related to the motor torque signature. We tested a worn gear and broken teeth. The rotating parts such as the valve shaft was reviewed and the actuator was checked additionally. For the tests, a simulator was designed and manufactured

  11. Plasma Fairings for Quieting Aircraft Landing Gear Noise Project

    National Aeronautics and Space Administration — This Phase II SBIR project deals with the design, development, and testing of a "Plasma Fairing" to reduce noise on the Gulfstream G550 landing gear. The plasma...

  12. The Dynamic Behaviour of Gears with High Transmission Ratio

    Ivana Atanasovska

    2012-06-01

    Full Text Available This paper describes the dynamic behaviour of helical gears with new standpoint for calculation of influence variables: mesh teeth stiffness, contact lines lengths and load distribution during mesh period. Nonlinear contact Finite Element Analysis and the new iteration procedure are used for calculation of meshed teeth deformations, stiffness and contact loads. The normal load distribution calculated with this procedure is used for evaluation of nonlinear dynamic analytical model of helical gears motion. Described investigation is especially important for gear pairs with high value of transmission ratio, often used in large transport machines. The presented models and results can be used for helical gears modeling when standard procedures don’t cover the requirements.

  13. Enhanced Prediction of Gear Tooth Surface Fatigue Life Project

    National Aeronautics and Space Administration — Sentient will develop an enhanced prediction of gear tooth surface fatigue life with rigorous analysis of the tribological phenomena that contribute to pitting...

  14. Research of Gear Fault Detection in Morphological Wavelet Domain

    Hong, Shi; Fang-jian, Shan; Bo, Cong; Wei, Qiu

    2016-02-01

    For extracting mutation information from gear fault signal and achieving a valid fault diagnosis, a gear fault diagnosis method based on morphological mean wavelet transform was designed. Morphological mean wavelet transform is a linear wavelet in the framework of morphological wavelet. Decomposing gear fault signal by this morphological mean wavelet transform could produce signal synthesis operators and detailed synthesis operators. For signal synthesis operators, it was just close to orginal signal, and for detailed synthesis operators, it contained fault impact signal or interference signal and could be catched. The simulation experiment result indicates that, compared with Fourier transform, the morphological mean wavelet transform method can do time-frequency analysis for original signal, effectively catch impact signal appears position; and compared with traditional linear wavelet transform, it has simple structure, easy realization, signal local extremum sensitivity and high denoising ability, so it is more adapted to gear fault real-time detection.

  15. OPTIMIZATION OF HEATING OF GEAR WHEEL USING NUMERICAL MODELING

    Soňa Benešová

    2013-09-01

    Full Text Available Successful heat treating and carburizing of gear wheels for wind turbine gear boxes requires that plastic deformation in the wheel is minimized. Numerical modeling using the DEFORM software was aimed at exploring the effects of the base, on which the gear wheel rests during heating, on the heating process. Homogeneous heating was assumed. It was found that the base heats up more quickly than the workpiece. It is the consequence of the base's shape and volume. As a result, the base expands and slides against the wheel, predominantly at the first heating stage. Later on, it prevents the gear wheel from expanding, causing plastic deformation in the wheel. The findings were used for designing new heating schedules to minimize these undesirable interactions and to reduce the plastic deformation to a negligible magnitude. In addition, this paper presents an example of a practical use of numerical modeling in the DEFORM software.

  16. OPTIMIZATION OF HEATING OF GEAR WHEEL USING NUMERICAL MODELING

    Sona Benesova

    2013-05-01

    Full Text Available Successful heat treating and carburizing of gear wheels for wind turbine gear boxes requires that plastic deformation in the wheel is minimized. Numerical modeling using the DEFORM software was aimed at exploring the effects of the base, on which the gear wheel rests during heating, on the heating process. Homogeneous heating was assumed. It was found that the base heats up more quickly than the workpiece. It is the consequence of the base's shape and volume. As a result, the base expands and slides against the wheel, predominantly at the first heating stage. Later on, it prevents the gear wheel from expanding, causing plastic deformation in the wheel. The findings were used for designing new heating schedules to minimize these undesirable interactions and to reduce the plastic deformation to a negligible magnitude. In addition, this paper presents an example of a practical use of numerical modeling in the DEFORM software.

  17. Experimental Measurements of Belt Gears in Newly Developed Device

    Jozef Mascenik

    2016-05-01

    Full Text Available The paper deals with the alternative of determination of state of the belt gear. To realize themeasurements a newly developed device was designed for measurement and diagnostics of the belt gears. The main task is to detect the V-belt slip expressed by the coefficient of elastic creep and of specific slip with a measuring device. The measurements regarding can be performed if input revolutions of the electric motor and torque of the belt gear are constant whereas the tensioning force of the belt gear changes. It is also possible to perform the measurement if the input revolutions of the electric motor and the tensioning forces are constant and the torque changes.

  18. Prediction of Landing Gear Loads Using Machine Learning Techniques

    Cross, Elizabeth; Worden, Keith; Sartor, Pia N; Southern, Paul

    2012-01-01

    This work aims to establish if significant correlations exist between flight parameters recorded on production aircraft and the loads induced in the landing gear by employing accurate nonlinear regression models developed using machine learning techniques. The mathematical modelling approach used in the development of the regression model employs both classical Multi-Layer Perceptron (MLP) and Bayesian MLP neural networks. The MLP neural networks in this work were developed using landing gear...

  19. Aircraf landing gear design in respect of pavement design

    Fabre, C.; ALBIN, A; Balay, Jean Maurice

    2009-01-01

    This paper considers the close relationship between aircraft landing gear (LG) and pavement design in respect of airfield pavement compatibility. In pavement design and analysis, we usually deal with pavement structures, materials and design thickness procedure but rarely aircraft LG design This paper emphasizes key drivers, which must be considered for new aircraft LG design to achieve aircraft pavement compatibility. Several parameters such as number & size of wheels, type of gear, brakes, ...

  20. A400M landing gear, loads measurement evaluation

    Rodríguez Juncosa, David

    2008-01-01

    Two A400M aircraft landing gears have been instrumented. The experience obtained with the first aircraft led some modifications to the second aircraft instrumentation. The project consists in studying the behaviour of the second aircraft landing gear loads measurements , as well as comparison with those of the first aircraft. The analysis of this comparison will lead to a proposal for an improvement of the measurement method (instrumentation, loading cases, etc).

  1. Magnetorheological landing gear: 2. Validation using experimental data

    Batterbee, D.C.; N.D. Sims; STANWAY, R.; Rennison, M.

    2007-01-01

    Aircraft landing gears are subjected to a wide range of excitation conditions with conflicting damping requirements. A novel solution to this problem is to implement semi-active damping using magnetorheological (MR) fluids. In part 1 of this contribution, a methodology was developed that enables the geometry of a flow mode MR valve to be optimized within the constraints of an existing passive landing gear. The device was designed to be optimal in terms of its impact performance, which was dem...

  2. Aeroacoustic control of landing gear noise using perforated fairings

    Boorsma, Koen

    2008-01-01

    A study was performed to investigate and optimize the application of perforated fairings for landing gear noise control. The sparse knowledge about this new subject has necessitated a more fundamental study involving a basic fairing-strut configuration, followed by wind tunnel tests on a simplified landing gear configuration incorporating perforated fairings. For the basic configuration, various exchangeable perforated half-cylindrical shells shrouding a circular cylinder we...

  3. Adaptive Landing Gear: Optimum Control Strategy and Potential for Improvement

    Grzegorz Mikułowski; Łukasz Jankowski

    2009-01-01

    An adaptive landing gear is a landing gear (LG) capable of active adaptation to particular landing conditions by means of controlled hydraulic force. The objective of the adaptive control is to mitigate the peak force transferred to the aircraft structure during touch-down, and thus to limit the structural fatigue factor. This paper investigates the ultimate limits for improvement due to various strategies of active control. Five strategies are proposed and investigated numerically using a~va...

  4. Darwin-industrien i højt gear

    2008-01-01

    Darwin-industrien i højt gear. Næste år bliver et 'Darwin-år' - både tilhængere og kritikere gør sig klar. Udgivelsesdato: 12. december......Darwin-industrien i højt gear. Næste år bliver et 'Darwin-år' - både tilhængere og kritikere gør sig klar. Udgivelsesdato: 12. december...

  5. Dynamics of High-Speed Precision Geared Rotor Systems

    Lim Teik C.

    2014-01-01

    Gears are one of the most widely applied precision machine elements in power transmission systems employed in automotive, aerospace, marine, rail and industrial applications because of their reliability, precision, efficiency and versatility. Fundamentally, gears provide a very practical mechanism to transmit motion and mechanical power between two rotating shafts. However, their performance and accuracy are often hampered by tooth failure, vibrations and whine noise. This is most acute in hi...

  6. Hydrostatic self-locking bevel differential gear; Hydrostatisch selbstsperrendes Kegelraddifferentialgetriebe

    Kalmbach, K.

    2001-07-01

    The product range of the rail vehicle industry comprises the construction of railroad material for long-distance and short-distance transport. This includes, for example, locomotives and cars, subway, light railway and tramway cars as well as rail vehicle equipment. The development of the industry is determined by the demand for transport services and government actions for the extension of railways and procurement of suitable vehicle types. In contrast to road vehicles, differential gears are only used in a negligible percentage of rail vehicles. Primarily in the short-distance rail transport sector, the demand for differential gears is growing due to increased drive power, smaller wheel diameters, lower vehicle mass with higher load capacity, the introduction of low-floor technology as well as the requirement of employing ever more quiet vehicles. In hydrostatic self-locking differential gears, oil is supplied to the gears within the differential gearbox. They only rotate relative to each other when the differential gear performs a compensation movement. In this case, oil is transported in the tooth space to the meshing of the gears, where it is displaced due to the meshing and must drain through tight gaps. The pressure generated by this process acts against the compensation movement of the gear, and the drive torque is transmitted to the wheel that has the higher friction. The achievable locking torque is linearly dependent on the differential speed of the drive wheel. This locking effect is achieved without wear-prone components and works automatically without active external intervention. The design space required corresponds to that of conventional differential gears, as the locking effect is integrated in the existing design. (orig.)

  7. A computer aided design procedure for generating gear teeth

    Chang, S. H.; Huston, R. L.; Coy, J. J.

    1984-01-01

    A procedure for computer aided design (CAD) of gear teeth is presented. It is developed for generated teeth fabricated by a hob cutter or a shaper. It provides a means for analytically and numerically determining the tooth profile, given the cutter profile. An illustrative example with involute tooth profiles is given. Application with non-standard profiles and with bevel, spiral bevel, and hypoid gears is discussed.

  8. QUALITY CONTROL ON THE AUSTENITIC-BAINITIC DUCTILE IRON GEAR

    2000-01-01

    By reasonable casting, spheroidizing , inoculating and heat treating processes to control cupola metallurgy and the lipuid iron chemical compositions, a new kind of austenitic-bainitic ductile iron which can substitute for 20CrMnTi carburizing steel is studied. The gears made by the cast iron are high in quality,low in weight and the production cost is greatly reduced. The mechanical properties of the gear, including wear resistance, fatigue resistance, durability and others, can be greatly improved.

  9. An Artificial Intelligence Approach for Gears Diagnostics in AUVs

    Graciliano Nicolás Marichal; María Lourdes Del Castillo; Jesús López; Isidro Padrón; Mariano Artés

    2016-01-01

    In this paper, an intelligent scheme for detecting incipient defects in spur gears is presented. In fact, the study has been undertaken to determine these defects in a single propeller system of a small-sized unmanned helicopter. It is important to remark that although the study focused on this particular system, the obtained results could be extended to other systems known as AUVs (Autonomous Unmanned Vehicles), where the usage of polymer gears in the vehicle transmission is frequent. Few st...

  10. Bebida com adição de soro de leite e fibra alimentar prebiótica

    Mirela Guedes Bosi

    2013-03-01

    Full Text Available O objetivo deste trabalho foi avaliar a aceitação sensorial de bebida não fermentada, com adição de inulina e polpa de acerola. Seis formulações foram desenvolvidas, com adição de 0, 20, 40, 60, 80 e 100% de soro. O pH do soro foi 6,59, e a acidez de 0,103% de ácido lático. Utilizou-se a escala hedônica de nove pontos no teste de aceitação. As médias hedônicas das amostras com 0, 20 e 40% de soro não diferiram significativamente e variaram entre 6 e 8 pontos. As bebidas desenvolvidas com até 60% de soro são alternativas interessantes para o aproveitamento desse subproduto em laticínios.

  11. High-order compact ADI method using predictor-corrector scheme for 2D complex Ginzburg-Landau equation

    Shokri, Ali; Afshari, Fatemeh

    2015-12-01

    In this article, a high-order compact alternating direction implicit (HOC-ADI) finite difference scheme is applied to numerical solution of the complex Ginzburg-Landau (GL) equation in two spatial dimensions with periodical boundary conditions. The GL equation has been used as a mathematical model for various pattern formation systems in mechanics, physics, and chemistry. The proposed HOC-ADI method has fourth-order accuracy in space and second-order accuracy in time. To avoid solving the nonlinear system and to increase the accuracy and efficiency of the method, we proposed the predictor-corrector scheme. Validation of the present numerical solutions has been conducted by comparing with the exact and other methods results and evidenced a good agreement.

  12. A Landing Gear Noise Reduction Study Based on Computational Simulations

    Khorrami, Mehdi R.; Lockard, David P.

    2006-01-01

    Landing gear is one of the more prominent airframe noise sources. Techniques that diminish gear noise and suppress its radiation to the ground are highly desirable. Using a hybrid computational approach, this paper investigates the noise reduction potential of devices added to a simplified main landing gear model without small scale geometric details. The Ffowcs Williams and Hawkings equation is used to predict the noise at far-field observer locations from surface pressure data provided by unsteady CFD calculations. Because of the simplified nature of the model, most of the flow unsteadiness is restricted to low frequencies. The wheels, gear boxes, and oleo appear to be the primary sources of unsteadiness at these frequencies. The addition of fairings around the gear boxes and wheels, and the attachment of a splitter plate on the downstream side of the oleo significantly reduces the noise over a wide range of frequencies, but a dramatic increase in noise is observed at one frequency. The increased flow velocities, a consequence of the more streamlined bodies, appear to generate extra unsteadiness around other parts giving rise to the additional noise. Nonetheless, the calculations demonstrate the capability of the devices to improve overall landing gear noise.

  13. Continued Evaluation of Gear Condition Indicator Performance on Rotorcraft Fleet

    Delgado, Irebert R.; Dempsey, Paula J.; Antolick, Lance J.; Wade, Daniel R.

    2013-01-01

    This paper details analyses of condition indicator performance for the helicopter nose gearbox within the U.S. Army's Condition-Based Maintenance Program. Ten nose gearbox data sets underwent two specific analyses. A mean condition indicator level analysis was performed where condition indicator performance was based on a 'batting average' measured before and after part replacement. Two specific condition indicators, Diagnostic Algorithm 1 and Sideband Index, were found to perform well for the data sets studied. A condition indicator versus gear wear analysis was also performed, where gear wear photographs and descriptions from Army tear-down analyses were categorized based on ANSI/AGMA 1010-E95 standards. Seven nose gearbox data sets were analyzed and correlated with condition indicators Diagnostic Algorithm 1 and Sideband Index. Both were found to be most responsive to gear wear cases of micropitting and spalling. Input pinion nose gear box condition indicators were found to be more responsive to part replacement during overhaul than their corresponding output gear nose gear box condition indicators.

  14. Surface Fatigue Life of High Temperature Gear Materials

    Townsend, Dennis P.

    1994-01-01

    Three high temperature gear materials were evaluated using spur gear surface fatigue tests. These materials were, VASCO max 350, VASCO matrix 2, and nitralloy N and were evaluated for possible use in high temperature gear applications. The fatigue life of the three high temperature gear materials were compared with the life of the standard AISI 9310 aircraft gear material. Surface fatigue tests were conducted at a lubricant inlet temperature of 321 K (120 F), a lubricant outlet temperature of 350 K (170 F), a maximum Hertz stress of 1.71 GPa (248 ksi), a speed of 10,000 rpm, and with a synthetic paraffinic lubricant. The life of the nitralloy N was approximately the same as the AISI 9310, the life of the VASCO max 350 was much less than the AISI 9310 while the life of the VASCO matrix 2 was several times the life of the AISI 9310. The VASCO max 350 also showed very low fracture toughness with approximately half of the gears failed by tooth fracture through the fatigue spall. The VASCO matrix 2 had approximately 10-percent fracture failure through the fatigue spalls indicating moderate to good fracture toughness.

  15. Fault Feature Analysis of a Cracked Gear Coupled Rotor System

    Hui Ma

    2014-01-01

    Full Text Available Considering the misalignment of gear root circle and base circle and accurate transition curve, an improved mesh stiffness model for healthy gear is proposed, and it is validated by comparison with the finite element method. On the basis of the improved method, a mesh stiffness model for a cracked gear pair is built. Then a finite element model of a cracked gear coupled rotor system in a one-stage reduction gear box is established. The effects of crack depth, width, initial position, and crack propagation direction on gear mesh stiffness, fault features in time domain and frequency domain, and statistical indicators are investigated. Moreover, fault features are also validated by experiment. The results show that the improved mesh stiffness model is more accurate than the traditional mesh stiffness model. When the tooth root crack appears, distinct impulses are found in time domain vibration responses, and sidebands appear in frequency domain. Amplitudes of all the statistical indicators ascend gradually with the growth of crack depth and width, decrease with the increasing crack initial position angle, and firstly increase and then decrease with the growth of propagation direction angle.

  16. Prevalence and predictors of selfmedication with antibiotics among Adi-haqi Campus students of Mekelle University, Ethiopia

    Tadele Eticha; Haylay Araya; Adissu Alemayehu; Gebremedhin Solomon; Dagim Ali

    2014-01-01

    Background: Self-medication with antibiotics is one form of antibiotic misuse which enhances the development of antibiotic resistance. Antibiotic resistance is a worldwide public health problem which leads to treatment failures causing deaths and an increase in health care costs. The objective of this study was to determine the prevalence and predictors of antibiotic self-medication among students of Adi-haqi Campus of Mekelle University (ACMU) in Mekelle, Ethiopia. Materials and methods: ...

  17. Influence of process parameters on the properties of austempered ductile iron (ADI examined with the use of data mining methods

    D. Wilk-Kołodziejczyk

    2016-10-01

    Full Text Available The article presents opportunities offered by the data mining analysis as applied to studies of the effect of process parameters on the mechanical properties of ADI. The applied methods of regression trees and cluster analysis allow for the detection of relationships between parameters and also allow determination of strength and form of the impact of different factors. The results of this study allow the creation of knowledge bases for systems supporting the decision-making process in technology.

  18. Limited Entry Fixed Gear 2009-10 (Collect cost and earning data from the Limited Entry (LE) fixed gear fleet)

    National Oceanic and Atmospheric Administration, Department of Commerce — Design and implement collection of economic data from the limited entry groundfish fixed gear fleet. Work includes identifying the survey population, developing a...

  19. One-step leapfrog ADI-FDTD method for simulating electromagnetic wave propagation in general dispersive media.

    Wang, Xiang-Hua; Yin, Wen-Yan; Chen, Zhi Zhang David

    2013-09-01

    The one-step leapfrog alternating-direction-implicit finite-difference time-domain (ADI-FDTD) method is reformulated for simulating general electrically dispersive media. It models material dispersive properties with equivalent polarization currents. These currents are then solved with the auxiliary differential equation (ADE) and then incorporated into the one-step leapfrog ADI-FDTD method. The final equations are presented in the form similar to that of the conventional FDTD method but with second-order perturbation. The adapted method is then applied to characterize (a) electromagnetic wave propagation in a rectangular waveguide loaded with a magnetized plasma slab, (b) transmission coefficient of a plane wave normally incident on a monolayer graphene sheet biased by a magnetostatic field, and (c) surface plasmon polaritons (SPPs) propagation along a monolayer graphene sheet biased by an electrostatic field. The numerical results verify the stability, accuracy and computational efficiency of the proposed one-step leapfrog ADI-FDTD algorithm in comparison with analytical results and the results obtained with the other methods. PMID:24103929

  20. Unveiling the Mechanism of Arginine Transport through AdiC with Molecular Dynamics Simulations: The Guiding Role of Aromatic Residues

    Krammer, Eva-Maria; Ghaddar, Kassem; André, Bruno

    2016-01-01

    Commensal and pathogenic enteric bacteria have developed several systems to adapt to proton leakage into the cytoplasm resulting from extreme acidic conditions. One such system involves arginine uptake followed by export of the decarboxylated product agmatine, carried out by the arginine/agmatine antiporter (AdiC), which thus works as a virtual proton pump. Here, using classical and targeted molecular dynamics, we investigated at the atomic level the mechanism of arginine transport through AdiC of E. coli. Overall, our MD simulation data clearly demonstrate that global rearrangements of several transmembrane segments are necessary but not sufficient for achieving transitions between structural states along the arginine translocation pathway. In particular, local structural changes, namely rotameric conversions of two aromatic residues, are needed to regulate access to both the outward- and inward-facing states. Our simulations have also enabled identification of a few residues, overwhelmingly aromatic, which are essential to guiding arginine in the course of its translocation. Most of them belong to gating elements whose coordinated motions contribute to the alternating access mechanism. Their conservation in all known E. coli acid resistance antiporters suggests that the transport mechanisms of these systems share common features. Last but not least, knowledge of the functional properties of AdiC can advance our understanding of the members of the amino acid-carbocation-polyamine superfamily, notably in eukaryotic cells. PMID:27482712

  1. 3-D ADI-FDTD modeling of GPR backscatter from complex targets for the training of artificial neural networks

    Sassen, D. S.; Everett, M. E.

    2007-12-01

    Artificial neural networks can provide approximate solutions to ground-penetrating radar (GPR) problems in cases where real time performance is needed. Examples include discrimination of landmines or UXO's, and in circumstances that require a high number of successive forward problems, for example inversion or imaging. The training of neural networks to work within even a limited range of targets and electromagnetic properties requires a large set of successive examples generated from numerical methods such as finite difference time domain (FDTD). The traditional FDTD technique suffers from numerical dispersion unless time steps are kept below the Courant stability limit. The accurate modeling of electromagnetic scattering by complex targets require a refined grid, subgrids, or conformal grids that can significantly increase computation time, making neural network training inefficient. A relatively recent FDTD technique, ADI-FDTD, uses implicit equations that help to cancel numerical dispersion and allow for unconditionally stable modeling of EM propagation and therefore is not bound by the Courant stability limit. The technique is especially efficient for the accurate modeling of complex targets. Our ADI-FDTD code includes the ability to refine the model grid and to implement a conformal gridding to improve model accuracy without effecting the overall computation time. We will explore the tradeoff in computation time and accuracy in modeling the GPR backscatter of various targets using both the ADI-FDTD technique and the traditional FDTD technique for the purpose of neural network training.

  2. Microstructure and Mechanical Properties of ADI Depending on Austenitization Methods and Parameters

    T. Giętka

    2012-04-01

    Full Text Available Ductile iron was quenched using two-variant isothermal transformation. The first treatment variant consisted of one-phase austenitization at a temperature t = 830, 860 or 900 C, cooling down to an isothermal transformation temperature of 300 or 400 C and holding from 8 to 64 minutes. The second treatment variant consisted of two-phase austenitization. Cast iron was austenitizied at a tem- perature t = 950 C and cooled down to a supercritical temperature t ’ = 900, 860 or 830 C. Isothermal transformation was conducted under the same conditions as those applied to the first variant. Ferrite cast iron was quenched isothermally. Basic strength (Rp0.2, Rm and plastic (A5 properties as well as matrix microstructure and hardness were examined.As a result of heat treatment, the following ADI grades were obtained: EN-GJS-800-8, EN-GJS-1200-2 and EN-GJS-1400-1 in accordance with PN–EN 1564:2000 having plasticity of 1.5÷4 times more than minimum requirements specified in the standard.

  3. POD/DEIM Nonlinear model order reduction of an ADI implicit shallow water equations model

    Stefanescu, Razvan

    2012-01-01

    In the present paper we consider a 2-D shallow-water equations (SWE) model on a $\\beta$-plane solved using an alternating direction fully implicit (ADI) finite-difference scheme on a rectangular domain. The scheme was shown to be unconditionally stable for the linearized equations. The discretization yields a number of nonlinear systems of algebraic equations. We then use a proper orthogonal decomposition (POD) to reduce the dimension of the SWE model. Due to the model nonlinearities, the computational complexity of the reduced model still depends on the number of variables of the full shallow - water equations model. By employing the discrete empirical interpolation method (DEIM) we reduce the computational complexity of the reduced order model due to its depending on the nonlinear full dimension model and regain the full model reduction expected from the POD model. To emphasize the CPU gain in performance due to use of POD/DEIM, we also propose testing an explicit Euler finite difference scheme (EE) as an a...

  4. Gear Design Effects on the Performance of High Speed Helical Gear Trains as Used in Aerospace Drive Systems

    Handschuh, R.; Kilmain, C.; Ehinger, R.; Sinusas, E.

    2013-01-01

    The performance of high-speed helical gear trains is of particular importance for tiltrotor aircraft drive systems. These drive systems are used to provide speed reduction / torque multiplication from the gas turbine output shaft and provide the necessary offset between these parallel shafts in the aircraft. Four different design configurations have been tested in the NASA Glenn Research Center, High Speed Helical Gear Train Test Facility. The design configurations included the current aircraft design, current design with isotropic superfinished gear surfaces, double helical design (inward and outward pumping), increased pitch (finer teeth), and an increased helix angle. All designs were tested at multiple input shaft speeds (up to 15,000 rpm) and applied power (up to 5,000 hp). Also two lubrication, system-related, variables were tested: oil inlet temperature (160 to 250 degF) and lubricating jet pressure (60 to 80 psig). Experimental data recorded from these tests included power loss of the helical system under study, the temperature increase of the lubricant from inlet to outlet of the drive system and fling off temperatures (radially and axially). Also, all gear systems were tested with and without shrouds around the gears. The empirical data resulting from this study will be useful to the design of future helical gear train systems anticipated for next generation rotorcraft drive systems.

  5. Vibration and Operational Characteristics of a Composite-Steel (Hybrid) Gear

    Handschuh, Robert F.; LaBerge, Kelsen E.; DeLuca, Samuel; Pelagalli, Ryan

    2014-01-01

    Hybrid gears have been tested consisting of metallic gear teeth and shafting connected by composite web. Both free vibration and dynamic operation tests were completed at the NASA Glenn Spur Gear Fatigue Test Facility, comparing these hybrid gears to their steel counterparts. The free vibration tests indicated that the natural frequency of the hybrid gear was approximately 800 Hz lower than the steel test gear. The dynamic vibration tests were conducted at five different rotational speeds and three levels of torque in a four square test configuration. The hybrid gears were tested both as fabricated (machined, composite layup, then composite cure) and after regrinding the gear teeth to the required aerospace tolerance. The dynamic vibration tests indicated that the level of vibration for either type of gearing was sensitive to the level of load and rotational speed.

  6. Aerodynamics of a Gulfstream G550 Nose Landing Gear Model

    Neuhart, Dan H.; Khorrami, Mehdi R.; Choudhari, Meelan M.

    2009-01-01

    In this paper we discuss detailed steady and unsteady aerodynamic measurements of a Gulfstream G550 nose landing gear model. The quarter-scale, high-fidelity model includes part of the lower fuselage and the gear cavity. The full model configuration allowed for removal of various gear components (e.g. light cluster, steering mechanism, hydraulic lines, etc.) in order to document their effects on the local flow field. The measurements were conducted at a Reynolds number of 7.3 x 10(exp 4) based on the shock strut (piston) diameter and a freestream Mach number of 0.166. Additional data were also collected at lower Mach numbers of 0.12 and 0.145 and correspondingly lower Reynolds numbers. The boundary layer on the piston was tripped to enable turbulent flow separation, so as to better mimic the conditions encountered during flight. Steady surface pressures were gathered from an extensive number of static ports on the wheels, door, fuselage, and within the gear cavity. To better understand the resultant flow interactions between gear components, surface pressure fluctuations were collected via sixteen dynamic pressure sensors strategically placed on various subcomponents of the gear. Fifteen of the transducers were flush mounted on the gear surface at fixed locations, while the remaining one was a mobile transducer that could be placed at numerous varying locations. The measured surface pressure spectra are mainly broadband in nature, lacking any local peaks associated with coherent vortex shedding. This finding is in agreement with off-surface flow measurements using PIV that revealed the flow field to be a collection of separated shear layers without any dominant vortex shedding processes.

  7. Parametric Analysis of the End Face Engagement Worm Gear

    DENG Xingqiao; WANG Jueling; WANG Jinge; CHEN Shouan; YANG Jie

    2015-01-01

    A novel specific type of worm drive, so-called end face engagement worm gear(EFEWD), is originally presented to minimize or overcome the gear backlash. Different factors, including the three different types, contact curves, tooth profile, lubrication angle and the induced normal curvature are taken into account to investigate the meshing characteristics and create the profile of a novel specific type of worm drive through mathematical models and theoretical analysis. The tooth of the worm wheel is very specific with the sine-shaped tooth which is located at the alveolus of the worm and the tooth profile of a worm is generated by the meshing movement of the worm wheel with the sine-shaped tooth, but just the end face of the worm(with three different typical meshing types) is adapted to meshing, and therefore an extraordinary manufacturing methods is used to generate the profile of the end face engagement worm. The research results indicates that the bearing contacts of the generated conjugate hourglass worm gear set are in line contacts, with certain advantages of no-backlash, high precision and high operating efficiency over other gears and gear systems besides the end face engagement worm gear drive may improve bearing contact, reduce the level of transmission errors and lessen the sensitivity to errors of alignment. Also, the end face engagement worm can be easily made with superior meshing and lubrication performance compared with the conventional techniques. In particular, the meshing and lubrication performance of the end face engagement worm gear by using the end face to meshing can be increased over 10% and 7%, respectively. This investigate is expect to provide a new insight on the design of the future no-backlash worm drive for industry.

  8. Parametric analysis of the end face engagement worm gear

    Deng, Xingqiao; Wang, Jueling; Wang, Jinge; Chen, Shouan; Yang, Jie

    2015-11-01

    A novel specific type of worm drive, so-called end face engagement worm gear(EFEWD), is originally presented to minimize or overcome the gear backlash. Different factors, including the three different types, contact curves, tooth profile, lubrication angle and the induced normal curvature are taken into account to investigate the meshing characteristics and create the profile of a novel specific type of worm drive through mathematical models and theoretical analysis. The tooth of the worm wheel is very specific with the sine-shaped tooth which is located at the alveolus of the worm and the tooth profile of a worm is generated by the meshing movement of the worm wheel with the sine-shaped tooth, but just the end face of the worm(with three different typical meshing types) is adapted to meshing, and therefore an extraordinary manufacturing methods is used to generate the profile of the end face engagement worm. The research results indicates that the bearing contacts of the generated conjugate hourglass worm gear set are in line contacts, with certain advantages of no-backlash, high precision and high operating efficiency over other gears and gear systems besides the end face engagement worm gear drive may improve bearing contact, reduce the level of transmission errors and lessen the sensitivity to errors of alignment. Also, the end face engagement worm can be easily made with superior meshing and lubrication performance compared with the conventional techniques. In particular, the meshing and lubrication performance of the end face engagement worm gear by using the end face to meshing can be increased over 10% and 7%, respectively. This investigate is expect to provide a new insight on the design of the future no-backlash worm drive for industry.

  9. The study about planetary gearbox virtual prototyping with nonlinear gear contact characteristics

    The virtual prototypes of gear transmission system built in most multi-body dynamic software have difficulties in describing the gear mesh characteristics. The gear mesh contact is modelled as rigid contact and this is not accurate for the gear mesh contact, which is elastic or flexible. The gear contact formula used in the multi-body dynamic software does not reveal the gear contact nonlinear stiffness characteristic. The model built with gear meshing contact is difficult to solve because of its time-consuming algorithm. In the paper a new method is put forward to build the virtual prototype of planetary gearbox system according to the nonlinear mesh stiffness and mesh phase obtained through FEM models. This new FEM method of gear mesh stiffness calculation is much more accurate than the common formulas. The gear mesh nonlinear stiffness of sun gear- pinion and pinion-ring gear of all the planetary gear sets in gearbox are obtained through MATALB code, which is used to read and plot the analyzing result data. The gear mesh phase differences between different pinions with suns or rings of different planetary gear set can be also obtained. With all these data modelled in simulink (or other software) and integrated with the multi-body dynamic planetary gearbox model and the gear meshing contact problem in multi-body gear models is solved easily and accurately. The interfaces for gear mesh stiffness and mesh phases are designed for multi-body dynamic model and simulink. The nonlinear planetary gear set prototyping models are integrated to become the whole planetary gear box model and the whole vehicle system model built in multi-body dynamic software can be integrated to simulate different duty conditions. At last high speed input is put into the nonlinear planetary transmission model and the different duty cases are simulated. The dynamic characteristics of different parts are obtained. The dynamic characteristic comparison between nonlinear and linear models is made

  10. Mathematical Modeling And Design Optimization Of Plunge Shaving Cutter For Gears With Tooth Modifications

    Chang, Shinn-Liang; Liu, Jia-Hung

    2009-10-01

    Gears are the most important components in transmission systems. Modifications of gear teeth can accommodate errors and deformations encountered in the manufacture, assembly, and operation of gear pairs. For plunge shaving gears with tooth modifications, the design criteria of cutter clearance manufactured by protuberance hob cutter is investigated. With this novel design, the cutter has better strength and stiffness to keep the shaved gear profile stable. With the analytical descriptions of crowned gear and hence plunge shaving cutter have been constructed so that the grinding wheel can be optimized to minimized the topographic error. Efficiency is greatly improved by avoiding the traditional trial and error method.

  11. One Approach to the Synthesis, Design and Manufacture of Hyperboloid Gear Sets With Face Mating Gears. Part 1: Basic Theoretical and Cad Experience

    Abadjiev Valentin

    2016-06-01

    Full Text Available Hyperboloid gear drives with face mating gears are used to transform rotations between shafts with non-parallel and non-intersecting axes. A special case of these transmissions are Spiroid and Helicon gear drives. The classical gear drives of this type are the Archimedean ones. The objective of this study are hyperboloid gear drives with face meshing, when the pinion possesses threads of conic convolute, Archimedean and involute types, or the pinion has threads of cylindrical convolute, Archimedean and involute types. For simplicity, all three types transmis- sions with face mating gears and a conic pinion are titled Spiroid and all three types transmissions with face mating gears and a cylindrical pinion are titled Helicon.

  12. Vibration Propagation of Gear Dynamics in a Gear-Bearing-Housing System Using Mathematical Modeling and Finite Element Analysis

    Parker, Robert G.; Guo, Yi; Eritenel, Tugan; Ericson, Tristan M.

    2012-01-01

    Vibration and noise caused by gear dynamics at the meshing teeth propagate through power transmission components to the surrounding environment. This study is devoted to developing computational tools to investigate the vibro-acoustic propagation of gear dynamics through a gearbox using different bearings. Detailed finite element/contact mechanics and boundary element models of the gear/bearing/housing system are established to compute the system vibration and noise propagation. Both vibration and acoustic models are validated by experiments including the vibration modal testing and sound field measurements. The effectiveness of each bearing type to disrupt vibration propagation is speed-dependent. Housing plays an important role in noise radiation .It, however, has limited effects on gear dynamics. Bearings are critical components in drivetrains. Accurate modeling of rolling element bearings is essential to assess vibration and noise of drivetrain systems. This study also seeks to fully describe the vibro-acoustic propagation of gear dynamics through a power-transmission system using rolling element and fluid film wave bearings. Fluid film wave bearings, which have higher damping than rolling element bearings, could offer an energy dissipation mechanism that reduces the gearbox noise. The effectiveness of each bearing type to disrupt vibration propagation in explored using multi-body computational models. These models include gears, shafts, rolling element and fluid film wave bearings, and the housing. Radiated noise is mapped from the gearbox surface to surrounding environment. The effectiveness of rolling element and fluid film wave bearings in breaking the vibro-acoustic propagation path from the gear to the housing is investigated.

  13. Aeroacoustic Evaluation of Flap and Landing Gear Noise Reduction Concepts

    Khorrami, Mehdi R.; Humphreys, William M., Jr.; Lockard, David P.; Ravetta, Patricio A.

    2014-01-01

    Aeroacoustic measurements for a semi-span, 18% scale, high-fidelity Gulfstream aircraft model are presented. The model was used as a test bed to conduct detailed studies of flap and main landing gear noise sources and to determine the effectiveness of numerous noise mitigation concepts. Using a traversing microphone array in the flyover direction, an extensive set of acoustic data was obtained in the NASA Langley Research Center 14- by 22-Foot Subsonic Tunnel with the facility in the acoustically treated open-wall (jet) mode. Most of the information was acquired with the model in a landing configuration with the flap deflected 39 deg and the main landing gear alternately installed and removed. Data were obtained at Mach numbers of 0.16, 0.20, and 0.24 over directivity angles between 56 deg and 116 deg, with 90 deg representing the overhead direction. Measured acoustic spectra showed that several of the tested flap noise reduction concepts decrease the sound pressure levels by 2 - 4 dB over the entire frequency range at all directivity angles. Slightly lower levels of noise reduction from the main landing gear were obtained through the simultaneous application of various gear devices. Measured aerodynamic forces indicated that the tested gear/flap noise abatement technologies have a negligible impact on the aerodynamic performance of the aircraft model.

  14. Computer Synthesis Approaches of Hyperboloid Gear Drives with Linear Contact

    Abadjiev, Valentin; Kawasaki, Haruhisa

    2014-09-01

    The computer design has improved forming different type software for scientific researches in the field of gearing theory as well as performing an adequate scientific support of the gear drives manufacture. Here are attached computer programs that are based on mathematical models as a result of scientific researches. The modern gear transmissions require the construction of new mathematical approaches to their geometric, technological and strength analysis. The process of optimization, synthesis and design is based on adequate iteration procedures to find out an optimal solution by varying definite parameters. The study is dedicated to accepted methodology in the creation of soft- ware for the synthesis of a class high reduction hyperboloid gears - Spiroid and Helicon ones (Spiroid and Helicon are trademarks registered by the Illinois Tool Works, Chicago, Ill). The developed basic computer products belong to software, based on original mathematical models. They are based on the two mathematical models for the synthesis: "upon a pitch contact point" and "upon a mesh region". Computer programs are worked out on the basis of the described mathematical models, and the relations between them are shown. The application of the shown approaches to the synthesis of commented gear drives is illustrated.

  15. Gear Mesh Loss-of-Lubrication Experiments and Analytical Simulation

    Handschuh, Robert F.; Polly, Joseph; Morales, Wilfredo

    2011-01-01

    An experimental program to determine the loss-of-lubrication (LOL) characteristics of spur gears in an aerospace simulation test facility has been completed. Tests were conducted using two different emergency lubricant types: (1) an oil mist system (two different misted lubricants) and (2) a grease injection system (two different grease types). Tests were conducted using a NASA Glenn test facility normally used for conducting contact fatigue. Tests were run at rotational speeds up to 10000 rpm using two different gear designs and two different gear materials. For the tests conducted using an air-oil misting system, a minimum lubricant injection rate was determined to permit the gear mesh to operate without failure for at least 1 hr. The tests allowed an elevated steady state temperature to be established. A basic 2-D heat transfer simulation has been developed to investigate temperatures of a simulated gear as a function of frictional behavior. The friction (heat generation source) between the meshing surfaces is related to the position in the meshing cycle, the load applied, and the amount of lubricant in the contact. Experimental conditions will be compared to those from the 2-D simulation.

  16. Pinion tooth surface generation strategy of spiral bevel gears

    Liu, Guanglei; Fan, Hongwei

    2012-07-01

    Aviation spiral bevel gears are often generated by spiral generated modified (SGM) roll method. In this style, pinion tooth surface modified generation strategy has an important influence on the meshing and contact performances. For the optimal contact pattern and transmission error function, local synthesis is applied to obtain the machine-tool settings of pinion. For digitized machine, four tooth surface generation styles of pinion are proposed. For every style, tooth contact analysis (TCA) is applied to obtain contact pattern and transmission error function. For the difference between TCA transmission error function and design objective curve, the degree of symmetry and agreement are defined and the corresponding sub-objective functions are established. Linear weighted combination method is applied to get an equivalent objective function to evaluate the shape of transmission error function. The computer programs for the process above are developed to analyze the meshing performances of the four pinion tooth surface generation styles for a pair of aviation spiral bevel gears with 38/43 teeth numbers. The four analytical results are compared with each other and show that the incomplete modified roll is optimal for this gear pair. This study is an expansion to generation strategy of spiral bevel gears, and offers new alternatives to computer numerical control (CNC) manufacture of spiral bevel gears.

  17. Materials and lubrication for gear and bearing surfaces in uhv

    During design and construction of the SLAC polarized LEED (PLEED) system, a search was made for a dependable gear, bearing, and lubrication system for the computer-controlled Faraday cup used to measure diffracted beams. Components must be nonmagnetic, bakeable to 2500C, and at room temperature must operate at pressures in the 10-9 to 10-10 Pa range. A test system was constructed which incorporated a meshed pair of dissimilar pitch diameter spur gears, one of which was confined to (by bushings) and rotated on a fixed shaft, while the other gear was driven by a commercial rotary motion feedthrough which was rotated by a servo motor driven in sine fashion with a direction reversal every six turns and peak speeds of 50 rpm. The criterion for a successful pair was approx. 105 turns, the life rating for the feedthrough. Pairs had actual turn counts from less than 1 to 91,000. Materials for gears included stainless steel, beryllium copper, and aluminum alloys. Lubricants used singly and in concert were MoS2, WS2, Ag, hard chrome, and a MoS2-graphite-sodium silicate mixture. The successful gear pair was Ag-plated Al alloy and MoS2-graphite-sodium silicate-coated Be-Cu. Subsequent performance in the PLEED system after repeated bakeouts will also be discussed

  18. Detailed modeling of gear losses; Detaillierte Modellierung von Getriebeverlusten

    Schlegel, Clemens [Schlegel Simulation GmbH, Freising (Germany); Hoesl, Andreas [BMW AG, Muenchen (Germany); Diel, Sergej [Hochschule Landshut (Germany)

    2011-07-01

    The torque losses of gears are an important part of the total losses of today's vehicle drive trains. From measurements it is known that transmission loss factors strongly vary over the operating range of a transmission (torque and rpm). This variation is due to the interaction of the losses of the individual transmission components such as bearings, gear et cetera. Since the emission regulations for vehicles are becoming more restrictive, the targeted reduction of losses in the design phase of a transmission already is highly desirable. The projections of losses helps to save costs (for example, for measurements). It accelerates the development and allows to investigate a series of drive concepts in a short time. In this paper, detailed semi-analytical loss models of the most common gear components are compiled from the literature and manufacturer's documents and implemented in a library of simulation models in the modeling language Modelica. This library contains models for radial seals, rotary joints, planetary gears, bearings of different designs, lubrication systems and lubrication oils. With this library, the loss of vehicle transmissions are calculated for any operating point (gear, torque, rpm, temperature). The results for a 7-speed dual-clutch gearbox are in good agreement with measurements.

  19. Hybrid Gear Preliminary Results-Application of Composites to Dynamic Mechanical Components

    Handschuh, Robert F.; Roberts Gary D.; Sinnamon, R.; Stringer, David B.; Dykas, Brian D.; Kohlman, Lee W.

    2012-01-01

    Composite spur gears were fabricated and then tested at NASA Glenn Research Center. The composite material served as the web of the gear between the gear teeth and a metallic hub for mounting to the torque-applying shaft. The composite web was bonded only to the inner and outer hexagonal features that were machined from an initially all-metallic aerospace quality spur gear. The Hybrid Gear was tested against an all-steel gear and against a mating Hybrid Gear. As a result of the composite to metal fabrication process used, the concentricity of the gears were reduced from their initial high-precision value. Regardless of the concentricity error, the hybrid gears operated successfully for over 300 million cycles at 10000 rpm and 490 in.*lbs torque. Although the design was not optimized for weight, the composite gears were found to be 20% lighter than the all-steel gears. Free vibration modes and vibration/noise tests were also conduct to compare the vibration and damping characteristic of the Hybrid Gear to all-steel gears. The initial results indicate that this type of hybrid design may have a dramatic effect on drive system weight without sacrificing strength.

  20. Combined Effects of Gravity, Bending Moment, Bearing Clearance, and Input Torque on Wind Turbine Planetary Gear Load Sharing: Preprint

    Guo, Y.; Keller, J.; LaCava, W.

    2012-09-01

    This computational work investigates planetary gear load sharing of three-mount suspension wind turbine gearboxes. A three dimensional multibody dynamic model is established, including gravity, bending moments, fluctuating mesh stiffness, nonlinear tooth contact, and bearing clearance. A flexible main shaft, planetary carrier, housing, and gear shafts are modeled using reduced degrees-of-freedom through modal compensation. This drivetrain model is validated against the experimental data of Gearbox Reliability Collaborative for gearbox internal loads. Planet load sharing is a combined effect of gravity, bending moment, bearing clearance, and input torque. Influences of each of these parameters and their combined effects on the resulting planet load sharing are investigated. Bending moments and gravity induce fundamental excitations in the rotating carrier frame, which can increase gearbox internal loads and disturb load sharing. Clearance in carrier bearings reduces the bearing load carrying capacity and thus the bending moment from the rotor can be transmitted into gear meshes. With bearing clearance, the bending moment can cause tooth micropitting and can induce planet bearing fatigue, leading to reduced gearbox life. Planet bearings are susceptible to skidding at low input torque.

  1. Variator loading and control in a V-belt type geared neutral transmission in and around the geared neutral point

    Veenhuizen, P.A.; Bonsen, B.; Klaassen, T.W.G.L.; Meerakker, K.G.O. van de; Veldpaus, F.E.

    2002-07-01

    Geared neutral transmissions still hold the promise of unparalleled transmission properties. The mechanism eliminates the need for a starting device and auxiliary clutches and gears for reverse. A very good launch feel without the use of a torque converter should be one of the main benefits. When combined with two clutches, resulting in a two-stage split-torque geared neutral transmission, the system can be augmented such that very high overdrive ratio's can be obtained, allowing low engine speeds at intermediate engine power levels to reduce fuel consumption. The mode shift can be carried out with a synchronised clutch. One of the main points of concern is the loading of the V-belt-type variator in and around the geared neutral point. It is the purpose of this paper to address this issue in some detail, taking both slip and torque loss into account. Variator control and variator loading in and around the geared neutral point will be addressed. (orig.)

  2. Coupled AXIAL-LATERAL-TORSIONAL Dynamics of a ROTOR-BEARING System Geared by Spur Bevel Gears

    LI, M.; HU, H. Y.; JIANG, P. L.; YU, L.

    2002-07-01

    The coupled lateral-torsional dynamics of parallel rotor-bearing systems has been intensively investigated. However, little attention has been paid to the analysis of coupled vibrations of angled rotor-bearing systems so that the torsional and the lateral vibrations of those systems are usually analyzed separately. In this paper, the coupled axial-lateral-torsional dynamics of a rotor-bearing system geared by bevel gears is studied. The meshing of two spur bevel gears is analyzed on the basis of a pair of virtual cylindrical gears, and thereafter the constraint condition describing the relationship between the generalized displacements of bevel gears is derived under some assumptions. The coupled dynamic model is established by using Lagrange's equation under this constraint condition. The numerical results of a number of case studies show that the critical speeds of the coupled model are different from those of the uncoupled model both in values and modes, and the threshold speed of stability is fairly less than that of the uncoupled model. The effects of system parameters, such as the pitch cone angles, on the coupling behavior are also discussed.

  3. Adaptive Landing Gear: Optimum Control Strategy and Potential for Improvement

    Grzegorz Mikułowski

    2009-01-01

    Full Text Available An adaptive landing gear is a landing gear (LG capable of active adaptation to particular landing conditions by means of controlled hydraulic force. The objective of the adaptive control is to mitigate the peak force transferred to the aircraft structure during touch-down, and thus to limit the structural fatigue factor. This paper investigates the ultimate limits for improvement due to various strategies of active control. Five strategies are proposed and investigated numerically using a~validated model of a real, passive landing gear as a reference. Potential for improvement is estimated statistically in terms of the mean and median (significant peak strut forces as well as in terms of the extended safe sinking velocity range. Three control strategies are verified experimentally using a laboratory test stand.

  4. Investigation of the paired-gear method in selectivity studies

    Sistiaga, Manu; Herrmann, Bent; Larsen, R.B.

    2009-01-01

    We estimated selectivity parameters using simultaneously the paired-gear and covered codend method for two fish species and four different selection systems, for a total of eight study cases. The deviation (Δ) in L50 and SR between these sampling methods observed in a former simulation study was...... repeated throughout the eight cases in this investigation. When using the paired-gear method, the distribution of the estimated L50 and SR is wider; the distribution of the estimated split parameter has a higher variability than the true split; the estimated mean L50 and SR can be biased; the estimated...... recommend that the methodology used to obtain selectivity estimates using the paired-gear method be reviewed....

  5. An efficient finite element solution for gear dynamics

    A finite element formulation for the dynamic response of gear pairs is proposed. Following an established approach in lumped parameter gear dynamic models, the static solution is used as the excitation in a frequency domain solution of the finite element vibration model. The nonlinear finite element/contact mechanics formulation provides accurate calculation of the static solution and average mesh stiffness that are used in the dynamic simulation. The frequency domain finite element calculation of dynamic response compares well with numerically integrated (time domain) finite element dynamic results and previously published experimental results. Simulation time with the proposed formulation is two orders of magnitude lower than numerically integrated dynamic results. This formulation admits system level dynamic gearbox response, which may include multiple gear meshes, flexible shafts, rolling element bearings, housing structures, and other deformable components.

  6. A new procedure for calculating contact stresses in gear teeth

    Somprakit, Paisan; Huston, Ronald L.

    1991-01-01

    A numerical procedure for evaluating and monitoring contact stresses in meshing gear teeth is discussed. The procedure is intended to extend the range of applicability and to improve the accuracy of gear contact stress analysis. The procedure is based upon fundamental solution from the theory of elasticity. It is an iterative numerical procedure. The method is believed to have distinct advantages over the classical Hertz method, the finite-element method, and over existing approaches with the boundary element method. Unlike many classical contact stress analyses, friction effects and sliding are included. Slipping and sticking in the contact region are studied. Several examples are discussed. The results are in agreement with classical results. Applications are presented for spur gears.

  7. An Experimental Study of Fretting of Gear Teeth

    Krantz, Timothy L.

    2008-01-01

    Experiments were conducted to study fretting of gears. The gears were made from case-carburized AISI 9310 alloy to match the material of a flight actuator gearbox of interest. The objective of the testing was to produce damage representative of that observed on flight hardware. The following correlations and observations were noted. The amplitude of dithering motion very strongly influenced the type and magnitude of damage. Sliding amounts on the order of 30% of the width of the line contact were judged to most readily produce fretting damage. There was observed an incubation period on the order of tens-of-thousands of cycles, and the incubation period was influenced by surface roughness, torque, and the motion extent. Fretting damage could be produced for any of the torques tested, and the severity of damage increased slightly with torque. Gear teeth having surface roughness of 0.7-0.8 micrometer were somewhat more resistant to fretting than were smoother surfaces.

  8. Unsteady Simulation of a Landing-Gear Flow Field

    Li, Fei; Khorrami, Mehdi R.; Malik, Mujeeb R.

    2002-01-01

    This paper presents results of an unsteady Reynolds-averaged Navier-Stokes simulation of a landing-gear flow field. The geometry of the four-wheel landing gear assembly consists of several of the fine details including the oleo-strut, two diagonal struts, a door, yokes/pin and a flat-plate simulating the wing surface. The computational results, obtained by using 13.3 million grid points, are presented with an emphasis on the characteristics of the unsteadiness ensuing from different parts of the landing-gear assembly, including vortex shedding patterns and frequencies of dominant oscillations. The results show that the presence of the diagonal struts and the door significantly influence the flow field. Owing to the induced asymmetry, vortices are shed only from one of the rear wheels and not the other. Present computations also capture streamwise vortices originating from the upstream corners of the door.

  9. Contact and Bending Durability Calculation for Spiral-Bevel Gears

    Vijayakar, Sandeep

    2016-01-01

    The objective of this project is to extend the capabilities of the gear contact analysis solver Calyx, and associated packages Transmission3D, HypoidFaceMilled, HypoidFaceHobbed. A calculation process for the surface durability was implemented using the Dowson-Higginson correlation for fluid film thickness. Comparisons to failure data from NASA's Spiral Bevel Gear Fatigue rig were carried out. A bending fatigue calculation has been implemented that allows the use of the stress-life calculation at each individual fillet point. The gears in the NASA test rig did not exhibit any bending fatigue failure, so the bending fatigue calculations are presented in this report by using significantly lowered strength numbers.

  10. Geared-elevator flutter study. [transonic flutter characteristics of empennage

    Ruhlin, C. L.; Doggett, R. V., Jr.; Gregory, R. A.

    1976-01-01

    The paper describes an experimental and analytical study of the transonic flutter characteristics of an empennage flutter model having an all-movable horizontal tail with a geared elevator. Two configurations were flutter tested: one with a geared elevator and one with a locked elevator with the model cantilever-mounted on a sting in the wind tunnel. The geared-elevator configuration fluttered experimentally at about 20% higher dynamic pressures than the locked-elevator configuration. The experimental flutter boundary was nearly flat at transonic speeds for both configurations. It was found that an analysis which treated the elevator as a discrete surface predicted flutter dynamic pressure levels better than analyses which treated the stabilizer and elevator as a warped surface. Warped-surface methods, however, predicted more closely the experimental flutter frequencies and Mach number trends.

  11. Spiral-Bevel-Gear Damage Detected Using Decision Fusion Analysis

    Dempsey, Paula J.; Handschuh, Robert F.

    2003-01-01

    Helicopter transmission integrity is critical to helicopter safety because helicopters depend on the power train for propulsion, lift, and flight maneuvering. To detect impending transmission failures, the ideal diagnostic tools used in the health-monitoring system would provide real-time health monitoring of the transmission, demonstrate a high level of reliable detection to minimize false alarms, and provide end users with clear information on the health of the system without requiring them to interpret large amounts of sensor data. A diagnostic tool for detecting damage to spiral bevel gears was developed. (Spiral bevel gears are used in helicopter transmissions to transfer power between nonparallel intersecting shafts.) Data fusion was used to integrate two different monitoring technologies, oil debris analysis and vibration, into a health-monitoring system for detecting surface fatigue pitting damage on the gears.

  12. Eddy current pulsed thermography for fatigue evaluation of gear

    Tian, Gui Yun; Yin, Aijun; Gao, Bin; Zhang, Jishan; Shaw, Brian

    2014-02-01

    The pulsed eddy current (PEC) technique generates responses over a wide range of frequencies, containing more spectral coverage than traditional eddy current inspection. Eddy current pulsed thermography (ECPT), a newly developed non-destructive testing (NDT) technique, has advantages such as rapid inspection of a large area within a short time, high spatial resolution, high sensitivity and stand-off measurement distance. This paper investigates ECPT for the evaluation of gear fatigue tests. The paper proposes a statistical method based on single channel blind source separation to extract details of gear fatigue. The discussion of transient thermal distribution and patterns of fatigue contact surfaces as well as the non-contact surfaces have been reported. In addition, the measurement for gears with different cycles of fatigue tests by ECPTand the comparison results between ECPT with magnetic Barkhausen noise (MBN) have been evaluated. The comparison shows the competitive capability of ECPT in fatigue evaluation.

  13. Dynamic hypoxic zones in Lake Erie compress fish habitat, altering vulnerability to fishing gears

    Kraus, Richard T.; Knight, Carey T.; Farmer, Troy M.; Gorman, Ann Marie; Collingsworth, Paris D.; Warren, Glenn J.; Kocovsky, Patrick M.; Conroy, Joseph D.

    2015-01-01

    Seasonal degradation of aquatic habitats from hypoxia occurs in numerous freshwater and coastal marine systems and can result in direct mortality or displacement of fish. Yet, fishery landings from these systems are frequently unresponsive to changes in the severity and extent of hypoxia, and population-scale effects have been difficult to measure except in extreme hypoxic conditions with hypoxia-sensitive species. We investigated fine-scale temporal and spatial variability in dissolved oxygen in Lake Erie as it related to fish distribution and catch efficiencies of both active (bottom trawls) and passive (trap nets) fishing gears. Temperature and dissolved oxygen loggers placed near the edge of the hypolimnion exhibited much higher than expected variability. Hypoxic episodes of variable durations were frequently punctuated by periods of normoxia, consistent with high-frequency internal waves. High-resolution interpolations of water quality and hydroacoustic surveys suggest that fish habitat is compressed during hypoxic episodes, resulting in higher fish densities near the edges of hypoxia. At fixed locations with passive commercial fishing gear, catches with the highest values occurred when bottom waters were hypoxic for intermediate proportions of time. Proximity to hypoxia explained significant variation in bottom trawl catches, with higher catch rates near the edge of hypoxia. These results emphasize how hypoxia may elevate catch rates in various types of fishing gears, leading to a lack of association between indices of hypoxia and fishery landings. Increased catch rates of fish at the edges of hypoxia have important implications for stock assessment models that assume catchability is spatially homogeneous.

  14. Estimating seabed pressure from demersal trawls, seines, and dredges based on gear design and dimensions

    Eigaard, Ole Ritzau; Bastardie, Francois; Breen, Mike;

    2016-01-01

    This study assesses the seabed pressure of towed fishing gears and models the physical impact (area and depth of seabed penetration) from trip-based information of vessel size, gear type, and catch. Traditionally fishing pressures are calculated top-down by making use of large-scale statistics such...... the gear's impact. An industry-based survey covering 13 countries provided the basis for estimating the relative impact-area contributions from individual gear components, whereas sediment penetration was estimated based on a literature review. For each gear group, a vessel size–gear size relationship...... was estimated to enable the prediction of gear footprint area and sediment penetration from vessel size. Application of these relationships with average vessel sizes and towing speeds provided hourly swept-area estimates by métier. Scottish seining has the largest overall gear footprint of ∼1.6 km2 h...

  15. Estimation of fatigue damage of airplane landing gear

    LIU Ke-ge; YAN Chu-liang; ZHANG Shu-ming

    2006-01-01

    Taking the main landing gears of fighter and transport airplanes as examples,the fatigue life was estimated by means of the Miner's rule and from the spectrum of the real measurements.The computed results show that the landing damage to the fighter and transport airplanes is 75% and 60% of the total damage,and the damage caused by the landing stroke is 40% of the landing-gear damage.The fatigue damage properties can provide important information for reliable designing and the structural optimization.

  16. Induction heating of gears - pulsing dual-frequency concept

    R. Przyłucki

    2013-04-01

    Full Text Available The paper concerns analysis of gears hardening process. In order to obtain required temperature distribution several variations of single and combined frequencies for selected gear-wheel configurations were considered. The paper includes the calculation models and analysis of geometry and current intensity as well frequency influence on temperature distribution of the tooth surface. All calculations have been carried out by means of the use of Flux3D simulation program, which enables to provide, coupled electromagnetic and temperature fields analysis.

  17. Gear Fault Detection Based on Teager-Huang Transform

    Hui Li

    2010-01-01

    Full Text Available Gear fault detection based on Empirical Mode Decomposition (EMD and Teager Kaiser Energy Operator (TKEO technique is presented. This novel method is named as Teager-Huang transform (THT. EMD can adaptively decompose the vibration signal into a series of zero mean Intrinsic Mode Functions (IMFs. TKEO can track the instantaneous amplitude and instantaneous frequency of the Intrinsic Mode Functions at any instant. The experimental results provide effective evidence that Teager-Huang transform has better resolution than that of Hilbert-Huang transform. The Teager-Huang transform can effectively diagnose the fault of the gear, thus providing a viable processing tool for gearbox defect detection and diagnosis.

  18. Fabrication of micro gear wheels by micropowder injection molding

    Haiqing Yin; Xuanhui Qu; Chengchang Jia

    2008-01-01

    The micropowder injection molding technology was investigated to fabricate the microsized gear wheels on a conventional injection molding machine. The feedstock comprised of carbonyl ferrum powder and a wax-based thermoplastic binder. Microinjection molding was fulfilled at about 423 K under 100 MPa. The heating system was applied to the die to improve the fluidity of the feedstock and subsequently the cooling system was used to enhance the strength of the green compacts after injection by decreasing the temperature of the die. The gear wheels were realized successfully with their addendum circle diameter ranging from 800 to 200 m and with the center hole as small as 60 μtm.

  19. Subsynchronous instability of a geared centrifugal compressor of overhung design

    Hudson, J. H.; Wittman, L. J.

    1980-01-01

    The original design analysis and shop test data are presented for a three stage (poster) air compressor with impellers mounted on the extensions of a twin pinion gear, and driven by an 8000 hp synchronous motor. Also included are field test data, subsequent rotor dynamics analysis, modifications, and final rotor behavior. A subsynchronous instability existed on a geared, overhung rotor. State-of-the-art rotor dynamics analysis techniques provided a reasonable analytical model of the rotor. A bearing modification arrived at analytically eliminated the instability.

  20. Procedure for the automatic mesh generation of innovative gear teeth

    Radicella Andrea Chiaramonte

    2016-01-01

    Full Text Available After having described gear wheels with teeth having the two sides constituted by different involutes and their importance in engineering applications, we stress the need for an efficient procedure for the automatic mesh generation of innovative gear teeth. First, we describe the procedure for the subdivision of the tooth profile in the various possible cases, then we show the method for creating the subdivision mesh, defined by two series of curves called meridians and parallels. Finally, we describe how the above procedure for automatic mesh generation is able to solve specific cases that may arise when dealing with teeth having the two sides constituted by different involutes.

  1. A Model to Determine Mesh Characteristics in a Gear Pair with Tooth Profile Error

    Qibin Wang; Peng Hu; Yimin Zhang; Yi Wang; Xu Pang; Cao Tong

    2014-01-01

    A method to determine the gear mesh stiffness, loaded transmission error, and tooth contact stress is presented with tooth profile error. The single tooth stiffness is calculated by the potential energy method. Contact stress is studied by the classic Hertzian elastic contact theory. Then two cases are presented for validation of the gear mesh stiffness model. It is demonstrated that the gear mesh stiffness model is effective for the gear pair with or without lead crown relief and tip and roo...

  2. Rational and affordable concepts of Landing Gear for small reentry vehicle demonstrators

    Fioriti, Marco; Cardile, Diego; Viola, Nicole; Chiesa, Sergio

    2012-01-01

    The paper proposes an innovative solution for landing gear of small space vehicles, in particular of technological demonstrators of reentry space vehicles. After explaining why small space vehicles can benefit from landing gears, the work investigates a solution, which avoids the use of fluidic systems and minimizes constraints on the whole vehicle, thus limiting cost raising and making the installation of the landing gear easier on vehicles that originally did not envisage landing gears

  3. Testing a wheeled landing gear system for the TH-57 helicopter.

    Heckman, Nancy L.

    1992-01-01

    Using the main gear from a Cessna 182 and the nose gear from a Grumman AAI-B, (patent pending) a comparison with the skid gear currently installed on the TH-57 helicopters was conducted. The initial comparison was done using a structural analysis program, GIFTS, to simultaneously analyze and compare the gear systems. Experimental data was used to verify program results. Experimental testing was conducted for further code validation and analysis of each system's advantages and disadvantages. W...

  4. Aerodynamic Measurements in a Wind Tunnel on Scale Models of a 777 Main Landing Gear

    Ringshia, Aditya K

    2006-01-01

    Aerodynamic measurements were taken over models of the Boeing 777 high fidelity isolated landing gear in the 6- by 6-foot Virginia Tech Stability Wind Tunnel (VT-SWT) at a free-stream Mach number of 0.16. Noise control devices (NCD) were developed at Virginia Tech [9] to reduce noise by shielding gear components, reducing wake interactions and by streamlining the flow around certain landing gear components. Aerodynamic measurements were performed to understand the flow over the landing gear a...

  5. Estimation of seafloor impact from demersal trawls, seines and dredges based on gear design and dimensions

    Eigaard, Ole Ritzau; Bastardie, Francois; Breen, Michael;

    types based on a review of the scientific literature. For each defined gear group a vessel-size (kW or total length) – gear size (total gear width or circumference) relationship was estimated to enable the prediction of gear footprint area and sediment penetration from vessel size. The implications for...... the definition and monitoring of fishing pressure indicators are far-reaching, and are discussed in context of an ecosystem approach to fisheries management (EAFM)...

  6. Numerical Analysis and Demonstration: Transmission Shaft Influence on Meshing Vibration in Driving and Driven Gears

    Xu Jinli; Su Xingyi; Peng Bo

    2015-01-01

    The variable axial transmission system composed of universal joint transmission shafts and a gear pair has been applied in many engineering fields. In the design of a drive system, the dynamics of the gear pair have been studied in detail. However few have paid attention to the effect on the system modal characteristics of the gear pair, arising from the universal joint transmission shafts. This work establishes a torsional vibration mathematical model of the transmission shaft, driving gear,...

  7. PITTING OF TOOTH FLANKS OF CROSSED HELICAL GEARS MADE OF SINTERED STEEL

    Miltenović, Đorđe; Tica, Milan; Miltenović, Aleksandar; Banić, Milan; Živković, Srđan; Mišković, Žarko

    2015-01-01

    Crossed helical gears are used in cars and in many household appliances. The trend towards increased comfort in motor vehicles has led to the utilisation of more than a hundred servo-drives in luxury class automobiles. Important advantages of crossed helical gears are their easy and inexpensive design, low noise performance and high gear ratio that can be realised in one step. Sintered steel is a material with very favourable properties for the manufacture of crossed helical gears. High deman...

  8. An investigation of factors related to the bycatch of small cetaceans in fishing gear

    Mackay, Alice I.

    2011-01-01

    The bycatch of cetaceans in fishing gear is considered to be one of the biggest conservation threats to these species. Gear modifications have the potential to reduce these bycatches in global fisheries but there is little available information on how such modifications may change the fishing performance of gear, or indeed the behavior of cetaceans interacting with fishing gear. Generalized linear models (GLMs) were used to identify factors related to cetacean bycatches in UK bottom set g...

  9. Second-order non-iterative ADI solution of non-linear partial differential equations. [Alternating Direction Implicit scheme

    Wolfshtein, M.; Hirsh, R. S.; Pitts, B. H.

    1975-01-01

    A new method for the solution of non-linear partial differential equations by an ADI procedure is described. Although the method is second order accurate in time, it does not require either iterations or predictor corrector methods to overcome the nonlinearity of the equations. Thus the computational effort required for the solution of the non-linear problem becomes similar to that required for the linear case. The method is applied to a two-dimensional 'extended Burgers equation'. Linear stability is studied, and some numerical solutions obtained. The improved accuracy obtained by the 2nd order truncation error is clearly manifested.

  10. [The problem of cancer in the work of Władysław Kopaczewski (1886-1953)].

    Daszkiewicz, P

    1994-01-01

    Having left Lódź in 1906 Władysław Kopaczewski (1886-1953) studied physics, chemistry and biology at Swiss universities. In 1911 he moved to France where he conducted research in coloidal chemistry simultaneously obtaining a physician's diploma and an MD. During 42 years he spent in France he was dealing with biological systems physics, doing research in medicine, nutritive chemistry and cosmetology. He created an original conception of cancer disease. His theory allowed him to provide the theoretical bases of the cancer physics and to suggest a diagnositic method to direct the search for means of the cancer therapy. PMID:11624929

  11. 77 FR 67261 - Airworthiness Directives; Aeronautical Accessories, Inc., High Landing Gear Forward Crosstube...

    2012-11-09

    ... Accessories, Inc., High Landing Gear Forward Crosstube Assembly AGENCY: Federal Aviation Administration (FAA... Accessories, Inc. (AAI) high landing gear forward crosstube assemblies (crosstubes) installed on Agusta S.p.A..., collapse of the landing gear, and subsequent loss of control of the helicopter. DATES: This AD is...

  12. 76 FR 472 - Harmonization of Airworthiness Standards for Transport Category Airplanes-Landing Gear Retracting...

    2011-01-05

    ... Airworthiness Standards for Transport Category Airplanes--Landing Gear Retracting Mechanisms and Pilot... transport category airplanes on landing gear retracting mechanisms and the pilot compartment view. This... in a stalling maneuver, and would add an additional requirement to keep the landing gear and doors...

  13. 77 FR 1614 - Harmonization of Airworthiness Standards for Transport Category Airplanes-Landing Gear Retracting...

    2012-01-11

    ... Register on January 5, 2011 (76 FR 472). The NPRM proposed to amend the standards for landing gear... Transport Category Airplanes--Landing Gear Retracting Mechanisms and Pilot Compartment View AGENCY: Federal... the airworthiness standards for transport category airplanes on landing gear retracting mechanisms...

  14. 14 CFR 29.497 - Ground loading conditions: landing gear with tail wheels.

    2010-01-01

    ... 14 Aeronautics and Space 1 2010-01-01 2010-01-01 false Ground loading conditions: landing gear... Requirements Ground Loads § 29.497 Ground loading conditions: landing gear with tail wheels. (a) General. Rotorcraft with landing gear with two wheels forward and one wheel aft of the center of gravity must...

  15. 14 CFR 27.549 - Fuselage, landing gear, and rotor pylon structures.

    2010-01-01

    ... 14 Aeronautics and Space 1 2010-01-01 2010-01-01 false Fuselage, landing gear, and rotor pylon... Requirements § 27.549 Fuselage, landing gear, and rotor pylon structures. (a) Each fuselage, landing gear, and... accelerated flight and landing conditions, including engine torque. (Secs. 604, 605, 72 Stat. 778, 49...

  16. 77 FR 5420 - Airworthiness Directives; Aeronautical Accessories Inc. High Landing Gear Aft Crosstube Assembly

    2012-02-03

    ... Accessories Inc. High Landing Gear Aft Crosstube Assembly AGENCY: Federal Aviation Administration (FAA), DOT... (AD) for the Aeronautical Accessories Inc. (AAI) High Landing Gear Aft Crosstube Assembly (aft... proposed actions are intended to prevent failure of a crosstube, collapse of the landing gear,...

  17. 77 FR 37768 - Airworthiness Directives; Aeronautical Accessories, Inc., High Landing Gear Aft Crosstube Assembly

    2012-06-25

    ... Accessories, Inc., High Landing Gear Aft Crosstube Assembly AGENCY: Federal Aviation Administration (FAA), DOT... Accessories, Inc. (AAI), High Landing Gear Aft Crosstube Assembly (aft crosstube) installed on certain Bell... failure of a crosstube, collapse of the landing gear, and subsequent loss of control of the...

  18. 14 CFR 27.497 - Ground loading conditions: landing gear with tail wheels.

    2010-01-01

    ... 14 Aeronautics and Space 1 2010-01-01 2010-01-01 false Ground loading conditions: landing gear... Requirements Ground Loads § 27.497 Ground loading conditions: landing gear with tail wheels. (a) General. Rotorcraft with landing gear with two wheels forward, and one wheel aft, of the center of gravity must...

  19. 46 CFR 78.47-55 - Instructions for changing steering gear.

    2010-10-01

    ... 46 Shipping 3 2010-10-01 2010-10-01 false Instructions for changing steering gear. 78.47-55... OPERATIONS Markings for Fire and Emergency Equipment, Etc. § 78.47-55 Instructions for changing steering gear..., relating in order, the different steps to be taken in changing to the emergency steering gear. Each...

  20. 76 FR 16610 - Proposed Information Collection; Comment Request; Pacific Islands Region Vessel and Gear...

    2011-03-24

    ... Islands Region Vessel and Gear Identification Requirements AGENCY: National Oceanic and Atmospheric... Western Pacific fishery management unit species display identification markings on the vessel and gear, as... require that certain fishing gear must be marked. In the pelagic longline fisheries, the vessel...

  1. 46 CFR 35.20-10 - Steering gear test-T/ALL.

    2010-10-01

    ... 46 Shipping 1 2010-10-01 2010-10-01 false Steering gear test-T/ALL. 35.20-10 Section 35.20-10... Steering gear test—T/ALL. On all tankships making voyages of more than 48 hours' duration, the entire steering gear, the whistle, the means of communication, and the signaling appliances between the bridge...

  2. 78 FR 17188 - Agency Information Collection Activities; Comment Request; Evaluation of the GEAR UP College...

    2013-03-20

    ... Agency Information Collection Activities; Comment Request; Evaluation of the GEAR UP College Savings... to this notice will be considered public records. Title of Collection: Evaluation of the GEAR UP... Undergraduate Programs (GEAR UP). This first Information Collection Request (ICR) for the study presents...

  3. 77 FR 36998 - Proposed Information Collection; Comment Request; Mandatory Shrimp Vessel and Gear...

    2012-06-20

    ... Shrimp Vessel and Gear Characterization Survey AGENCY: National Oceanic and Atmospheric Administration... Shrimp Fishery Management Plan (FMP). The regulations for the Gulf Shrimp Vessel and Gear... and Gear Characterization Form. The form will be provided by NMFS at the time of permit...

  4. 78 FR 40436 - Proposed Information Collection; Comment Request; Mandatory Shrimp Vessel and Gear...

    2013-07-05

    ... Shrimp Vessel and Gear Characterization Survey AGENCY: National Oceanic and Atmospheric Administration... Shrimp Fishery Management Plan (FMP). The regulations for the Gulf Shrimp Vessel and Gear... Gear Characterization Form. The form will be provided by NMFS at the time of permit application...

  5. On the Transmission Noise of Machine Gears and an Effective Solution

    WANG Mei

    2009-01-01

    Noise pollution has become one of the world's three major pollutions. In modem industrial enterprises, the noise from gear transmission is an important source of pollution. In this paper, we first analyse the noise of a gear transmission system. Then, through repairing the margin of gear, using shaving processing, shaving cutter grind- ing to present an effective solution.

  6. Minimizing tooth bending stress in spur gears with simplified shapes of fillet and tool shape determination

    Pedersen, Niels Leergaard

    2015-01-01

    different standards, with the ISO standard probably being the most common one. Gears are manufactured using two principally different tools: rack tools and gear tools. In this work, the bending stress of involute teeth is minimized by shape optimization made directly on the final gear. This optimized shape...

  7. TRANSMISSION MOMENTARY EFFICIENCY BASED ON THE D'ALEMBERT-LAGRANGE EQUATION FOR INVOLUTES GEARS

    Liang Yi; Lai Changying

    2004-01-01

    The D'Alembert-Lagrange equation is introduced and used to derive the formulas of momentary efficiency for external gearing of standard involutes spur gears.The gearings with correct and increased center distance are discussed.The momentary efficiency formula is calculated and analyzed using software Matlab.The derived formula of momentary efficiency is also compared with the traditional formula.

  8. LUBRICATION BASIS THEORY OF WORM PAIR AND TEMPERATURE DISTRIBUTION ON WORM GEAR SURFACE

    1998-01-01

    The lubrication basis theory of worm pair is given. The lubrication state of worm gear is analyzed. It is found that the temperature distribution on the tooth surface of worm gear is closely related with the lubrication state and that the temperature on the tooth surface of worm gear is consistent with the characteristic term of mesh and motion of worm pair.

  9. 50 CFR 660.382 - Limited entry fixed gear fishery management measures.

    2010-10-01

    ... 50 Wildlife and Fisheries 9 2010-10-01 2010-10-01 false Limited entry fixed gear fishery... COAST STATES West Coast Groundfish Fisheries § 660.382 Limited entry fixed gear fishery management... participating in the limited entry groundfish fixed gear fishery and may not be exceeded. Federal...

  10. 50 CFR 660.216 - Fixed gear fishery-observer requirements.

    2010-10-01

    ... 50 Wildlife and Fisheries 9 2010-10-01 2010-10-01 false Fixed gear fishery-observer requirements. 660.216 Section 660.216 Wildlife and Fisheries FISHERY CONSERVATION AND MANAGEMENT, NATIONAL OCEANIC... West Coast Groundfish-Limited Entry Fixed Gear Fisheries § 660.216 Fixed gear...

  11. 50 CFR 600.747 - Guidelines and procedures for determining new fisheries and gear.

    2010-10-01

    ... new fisheries and gear. 600.747 Section 600.747 Wildlife and Fisheries FISHERY CONSERVATION AND... paragraph (b) for determining when fishing gear or a fishery is sufficiently different from those listed in... fishing gear or a fishery is sufficiently different from those listed to require notification of...

  12. 50 CFR 660.231 - Limited entry fixed gear sablefish primary fishery.

    2010-10-01

    ... primary fishery. This section applies to the sablefish primary season for the limited entry fixed gear fishery north of 36° N. lat. Limited entry and open access fixed gear sablefish fishing outside of the... primary season for the limited entry fixed gear fishery, unless at least one limited entry permit...

  13. 50 CFR Table 15 to Part 679 - Gear Codes, Descriptions, and Use

    2010-10-01

    ... 50 Wildlife and Fisheries 9 2010-10-01 2010-10-01 false Gear Codes, Descriptions, and Use 15 Table 15 to Part 679 Wildlife and Fisheries FISHERY CONSERVATION AND MANAGEMENT, NATIONAL OCEANIC AND... ALASKA Pt. 679, Table 15 Table 15 to Part 679—Gear Codes, Descriptions, and Use Gear Codes,...

  14. 50 CFR 660.220 - Fixed gear fishery-crossover provisions.

    2010-10-01

    ... 50 Wildlife and Fisheries 9 2010-10-01 2010-10-01 false Fixed gear fishery-crossover provisions. 660.220 Section 660.220 Wildlife and Fisheries FISHERY CONSERVATION AND MANAGEMENT, NATIONAL OCEANIC... West Coast Groundfish-Limited Entry Fixed Gear Fisheries § 660.220 Fixed gear...

  15. 75 FR 55301 - Proposed Information Collection; Comment Request; Northeast Region Gear Identification Requirements

    2010-09-10

    ... identifying characters on fishing gear aids in fishery law enforcement, and the marking of gear for visibility... Region Gear Identification Requirements AGENCY: National Oceanic and Atmospheric Administration (NOAA... Lindsey.Feldman@noaa.gov . SUPPLEMENTARY INFORMATION: I. Abstract Under the Magnuson-Stevens...

  16. Optimization of PHEV Power Split Gear Ratio to Minimize Fuel Consumption and Operation Cost

    Li, Yanhe

    A Plug-in Hybrid Electric Vehicle (PHEV) is a vehicle powered by a combination of an internal combustion engine and an electric motor with a battery pack. The battery pack can be charged by plugging the vehicle to the electric grid and from using excess engine power. The research activity performed in this thesis focused on the development of an innovative optimization approach of PHEV Power Split Device (PSD) gear ratio with the aim to minimize the vehicle operation costs. Three research activity lines have been followed: • Activity 1: The PHEV control strategy optimization by using the Dynamic Programming (DP) and the development of PHEV rule-based control strategy based on the DP results. • Activity 2: The PHEV rule-based control strategy parameter optimization by using the Non-dominated Sorting Genetic Algorithm (NSGA-II). • Activity 3: The comprehensive analysis of the single mode PHEV architecture to offer the innovative approach to optimize the PHEV PSD gear ratio.

  17. 14 CFR 125.187 - Landing gear: Aural warning device.

    2010-01-01

    ... 14 Aeronautics and Space 3 2010-01-01 2010-01-01 false Landing gear: Aural warning device. 125.187 Section 125.187 Aeronautics and Space FEDERAL AVIATION ADMINISTRATION, DEPARTMENT OF TRANSPORTATION (CONTINUED) AIR CARRIERS AND OPERATORS FOR COMPENSATION OR HIRE: CERTIFICATION AND OPERATIONS CERTIFICATION AND OPERATIONS: AIRPLANES HAVING...

  18. Retraction Assembly for Space Shuttle Extended Nose Landing Gear

    Files, Bradley S.; Nicholson, Leonard S. (Technical Monitor)

    2000-01-01

    As part of a project to encourage the use of shape memory alloy actuators for space actuators, this mechanism uses a nitinol ribbon to provide the necessary motion to help retract the proposed extended nose landing gear (ENLG) for the space shuttle. Initial proof-of-concept design of the ENLG did not include the ability to retract the gear automatically. One proposed actuator for this purpose was designed at Johnson Space Center and uses resistive heating to rotate the ribbon around a cylinder. This rotation then allows the assembly to pull down a wedge that is used to hold the landing gear strut in place, thus returning the landing gear to its previous height before extension. The presentation will follow the design of this assembly from working with the nitinol ribbon to providing mechanical connections and allowing minimal friction for motion of three wraps around a cylinder. Also to be presented is preliminary work on design of a shape memory alloy gripper, a design project to demonstrate uses of NiTi.

  19. Innovative Anti Crash Absorber for a Crashworthy Landing Gear

    Guida, Michele; Marulo, Francesco; Montesarchio, Bruno; Bruno, Massimiliano

    2014-06-01

    This paper defines an innovative concept to anti-crash absorber in composite material to be integrated on the landing gear as an energy-absorbing device in crash conditions to absorb the impact energy. A composite cylinder tube in carbon fiber material is installed coaxially to the shock absorber cylinder and, in an emergency landing gear condition, collapses in order to enhance the energy absorption performance of the landing system. This mechanism has been developed as an alternative solution to a high-pressure chamber installed on the Agusta A129 CBT helicopter, which can be considered dangerous when the helicopter operates in hard and/or crash landing. The characteristics of the anti-crash device are presented and the structural layout of a crashworthy landing gear adopting the developed additional energy absorbing stage is outlined. Experimental and numerical results relevant to the material characterization and the force peaks evaluation of the system development are reported. The anti-crash prototype was designed, analysed, optimized, made and finally the potential performances of a landing gear with the additional anti-crash absorber system are tested by drop test and then correlated with a similar test without the anti-crash system, showing that appreciable energy absorbing capabilities and efficiencies can be obtained in crash conditions.

  20. 14 CFR 121.289 - Landing gear: Aural warning device.

    2010-01-01

    ... 14 Aeronautics and Space 3 2010-01-01 2010-01-01 false Landing gear: Aural warning device. 121.289 Section 121.289 Aeronautics and Space FEDERAL AVIATION ADMINISTRATION, DEPARTMENT OF TRANSPORTATION (CONTINUED) AIR CARRIERS AND OPERATORS FOR COMPENSATION OR HIRE: CERTIFICATION AND OPERATIONS OPERATING REQUIREMENTS: DOMESTIC, FLAG,...

  1. Investigation of Current Methods to Identify Helicopter Gear Health

    Dempsey, Paula J.; Lewicki, David G.; Le, Dy D.

    2007-01-01

    This paper provides an overview of current vibration methods used to identify the health of helicopter transmission gears. The gears are critical to the transmission system that provides propulsion, lift and maneuvering of the helicopter. This paper reviews techniques used to process vibration data to calculate conditions indicators (CI's), guidelines used by the government aviation authorities in developing and certifying the Health and Usage Monitoring System (HUMS), condition and health indicators used in commercial HUMS, and different methods used to set thresholds to detect damage. Initial assessment of a method to set thresholds for vibration based condition indicators applied to flight and test rig data by evaluating differences in distributions between comparable transmissions are also discussed. Gear condition indicator FM4 values are compared on an OH58 helicopter during 14 maneuvers and an OH58 transmission test stand during crack propagation tests. Preliminary results show the distributions between healthy helicopter and rig data are comparable and distributions between healthy and damaged gears show significant differences.

  2. From testbed to reality grid computing steps up a gear

    2004-01-01

    "UK plans for Grid computing changed gear this week. The pioneering European DataGrid (EDG) project came to a successful conclusion at the end of March, and on 1 April a new project, known as Enabling Grids for E-Science in Europe (EGEE), begins" (1 page)

  3. Risk assessment of soils identified on firefighter turnout gear.

    Easter, Elizabeth; Lander, Deborah; Huston, Tabitha

    2016-09-01

    The purpose of this research was to identify the composition of soils on firefighter turnout gear and to determine the dermal exposure risks associated with the soils. Nine used Nomex hoods from the Philadelphia fire department were analyzed for the presence of trace metals and seven sets of used turnout gear were analyzed for semi-volatile organics. Turnout gear samples were removed from areas of the gear known to have high levels of dermal absorption including the collar, armpit, wrist, and crotch areas, from either the outer shell or thermal liner layers. The following compounds were detected: polycyclic aromatic hydrocarbons (PAHs), phthalate plasticizers, and polybrominated diphenyl ether flame retardants (PBDEs). A screening risk assessment was conducted by converting the measured concentrations to an estimated dermally absorbed dose based on estimates for the permeation coefficient (Kp) and an assumed firefighting exposure scenario. Benzo(a) pyrene had the highest dermal exposure risk based on carcinogenic effects and PBDE-99 had the highest dermal exposure risk based on non-carcinogenic effects. For the metals, arsenic had the highest dermal exposure risk for the use hoods. PMID:27027971

  4. Dynamics of simple gearing model with flexible planetary pins

    Půst, Ladislav; Pešek, Luděk; Radolfová, Alena

    2016-01-01

    Roč. 821, č. 2016 (2016), s. 284-281. ISSN 1660-9336 R&D Projects: GA TA ČR TA04011656 Institutional support: RVO:61388998 Keywords : lanetary gearings set * vibrations * rig wheel excitation * driving aggregate Subject RIV: BI - Acoustics

  5. LOADING OF MECHANICAL TRANSMISSION OF TROLLEYBUS TRACTION DRIVING GEAR

    A. I. Safonov

    2009-01-01

    Full Text Available The paper analyzes factors that determine dynamic loads of mechanical transmission of trolleybus traction driving gear. The paper proposes a methodology for determination of calculative moments of loading transmission elements. Results of the research are analyzed and recommendations on  dynamic reduction of trolleybus transmission are given in the paper. 

  6. Development of a high-performance magnetic gear

    Rasmussen, Peter Omand; Andersen, Torben Ole; Jørgensen, Frank Thorleif;

    2005-01-01

    components in the magnetic gear is also performed in order to figure out why the efficiency for the actual construction was only 81 %. A large magnetic 1055 component originated in the bearings, where an unplanned extra bearing was necessary due to mechanical problems. Without the losses of magnetic origin...

  7. Two dimensional model of a permanent magnet spur gear

    Jørgensen, Frank Thorleif; Andersen, Torben Ole; Rasmussen, Peter Omand

    2005-01-01

    analysis of the loss components in the magnetic gear is also performed in order to figure out why the efficiency for the actual construction was only 81%. A large magnetic loss component originated in the bearings, where an unplanned extra bearing was necessary due to mechanical problems. Without the...

  8. Marine Hydrokinetic Power Take-Off Using Magnetic Gearing

    Bird, Jonathan Z.

    2014-01-01

    This paper reviews different power take-off approaches for rotary based marine hydrokinetic power generation. The technology for wind power generation is used as a guide. A discussion on the potential benefits of utilizing magnetic gearing is presented. University of North Carolina at Chapel Hill. Coastal Studies Institute

  9. Head Gear incline shaft, showing engine houses and skip tipping

    Middlebrook, J E, fl 1890-1899, photographer

    2003-01-01

    207 x 153 mm. Showing the headgear machinery for lifting the trolleys to the surface, with the skips into which is poured the blue ground beyond, and the driving gear in the engine house in the background. A few figures sit in the foreground posed for the photographer.

  10. Motor integrated permanent magnet gear in a battery electrical vehicle

    Frandsen, Tommy; Mathe, Laszlo; Berg, Nick Ilsø;

    2013-01-01

    This paper presents the physical construction and test results of two new demonstrators of a Motor Integrated Permanent Magnet Gear (MIPMG), which is a second version of an already tested demonstrator. The demonstrators will be used as traction units for a Battery Electrical Vehicle (BEV) and the...

  11. Motor Integrated Permanent Magnet Gear in a Battery Electrical Vehicle

    Frandsen, Tommy; Mathe, Laszlo; Berg, Nick Ilsø;

    2015-01-01

    This paper presents the physical construction and test results of two new demonstrators of a Motor Integrated Permanent Magnet Gear (MIPMG), which is a second version of an already tested demonstrator. The demonstrators will be used as traction units for a Battery Electrical Vehicle (BEV) and the...

  12. 50 CFR 654.6 - Vessel and gear identification.

    2010-10-01

    ... 50 Wildlife and Fisheries 8 2010-10-01 2010-10-01 false Vessel and gear identification. 654.6 Section 654.6 Wildlife and Fisheries FISHERY CONSERVATION AND MANAGEMENT, NATIONAL OCEANIC AND ATMOSPHERIC ADMINISTRATION, DEPARTMENT OF COMMERCE STONE CRAB FISHERY OF THE GULF OF MEXICO General Measures § 654.6...

  13. 29 CFR 1918.62 - Miscellaneous auxiliary gear.

    2010-07-01

    ... sling's rated capacity. (2) Synthetic web slings shall be removed from service if they exhibit any of... tested by the repairer to twice the sling's rated capacity before its return to service. The employer... of a lifting appliance or item of loose gear installed after January 21, 1998 shall not...

  14. The additon of screws and the axodes of gear pairs

    ZHANG Wen-xiang

    2001-01-01

    In the light of screw addition, the distribution of instantaneous axes along the common perpendicular of the two screws is determined and all possible sorts of axodes are derived cinematically with the pitch of the relative-motio n screw in the gear pair as the basis and the transmission ratio i as an inde pendent variable.

  15. 50 CFR 300.108 - Vessel and gear identification.

    2010-10-01

    ... harvesting vessel is engaged (as described at 33 CFR part 81). (c) Gear identification. (1) The operator of... contrast to the background and must be permanently affixed to the harvesting vessel in block roman alphabet letters and arabic numerals at least 1 m in height for harvesting vessels over 20 m in length, and...

  16. The additon of screws and the axodes of gear pairs

    张文祥

    2001-01-01

    In the light of screw addition, the distribution of instantaneous axes along the common perpendicular of the two screws is determined and all possible sorts of axodes are derived cinematically with the pitch of the relative-motion screw in the gear pair as the basis and the transmission ratio i as an independent variable.

  17. Aeroacoustic characterization of scaled canonical nose landing gear configurations

    Zawodny, Nikolas S.

    Aircraft noise is a critical issue in the commercial airline industry. Airframe noise is a subcomponent of aircraft noise and is generally dominant over jet engine noise during approach conditions, which can lead to high community impact. Landing gears have been identified as major components of airframe noise during landing configurations for commercial aircraft. They are perhaps the least understood contributors to airframe noise due to complex flow patterns associated with intricate gear component geometries. Nose landing gear in particular have received much attention in recent years, exhibiting acoustic signatures on the order of the main landing gear assembly of an aircraft, while simultaneously being more amenable to scaled wind tunnel testing. In order to characterize the acoustic signature of a complex geometry such as a nose landing gear, it is important to isolate, study, and understand the acoustic contributions of individual component geometries. The purpose of this dissertation is to develop a correlation between the complex flow field nature and far-field acoustic signature of a nose landing gear sub-system. The model under investigation is a 1/2-scale shock-strut cylinder coupled with an adjustable torque link apparatus. This geometry was chosen due to its fundamental importance and implementation across a wide span of commercial aircraft. The fluid dynamic (surface pressure and stereoscopic particle image velocimety) and aeroacoustic (far-field microphone and phased array) experiments were performed in the University of Florida Aeroacoustic Flow Facility. The experimental data compare favorably with the results of a numerical simulation using PowerFLOW, a lattice-Boltzmann solver developed by the Exa Corporation. The far-field acoustic results of this dissertation have shown non-uniform scaling behavior as a function of frequency for the different model configurations tested. For frequencies that appropriately satisfied the condition of acoustic

  18. On the performance of SPAI and ADI-like preconditioners for core collapse supernova simulations in one spatial dimension

    The simulation of core collapse supernovae calls for the time accurate solution of the (Euler) equations for inviscid hydrodynamics coupled with the equations for neutrino transport. The time evolution is carried out by evolving the Euler equations explicitly and the neutrino transport equations implicitly. Neutrino transport is modeled by the multi-group Boltzmann transport (MGBT) and the multi-group flux limited diffusion (MGFLD) equations. An implicity time stepping scheme for the MGBT and MGFLD equations yields Jacobian systems that necessitate scaling and reconditioning. Two types of preconditioners, namely a sparse approximate inverse (SPAI) preconditioner and a preconditioner based on the alternating direction implicit iteration (ADI-like) have been fond to be effective for the MGFLD and MGBT formulations. This paper compares these two preconditioners. The ADI-like preconditioner performs well with both MGBT and MGFLD systems. For the MGBT system tested, the SPAI preconditioner did not give competitive results. However, since the MGBT system in our experiments had a high condition number before scaling and since we used a sequential platform, care must be taken in evaluating these results

  19. On the Performance of SPAI and ADI-like Preconditioners for Core Collapse Supernova Simulations in One Spatial Dimension

    The simulation of core collapse supernovae calls for the time accurate solution of the (Euler) equations for inviscid hydrodynamics coupled with the equations for neutrino transport. The time evolution is carried out by evolving the Euler equations explicitly and the neutrino transport equations implicitly. Neutrino transport is modeled by the multi-group Boltzmann transport (MGBT) and the multi-group flux-limited diffusion (MGFLD) equations. An implicit time-stepping scheme for the MGBT and MGFLD equations yields Jacobian systems that necessitate scaling and preconditioning. Two types of preconditioners, namely, a sparse approximate inverse (SPAI) preconditioner and a preconditioner based on the alternating direction-implicit iteration (ADI-like) have been found to be effective for the MGFLD and MGBT formulations. This paper compares these two preconditioners. The ADI-like preconditioner performs well with both MGBT and MGFLD systems. For the MGBT system tested, the SPAI preconditioner did not give competitive results. However, since the MGBT system in our experiments had a high condition number before scaling and since we used a sequential platform, care must be taken in evaluating these results.

  20. One Approach to the Synthesis, Design and Manufacture of Hyperboloid Gear Sets with Face Mating Gears. Part 2: Review of Practical Realization

    Abadjiev Valentin

    2016-09-01

    Full Text Available Hyperboloid gear drives with face mating gears are used to transform rotations between shafts with non-parallel and non-intersecting axes. A special case of these transmissions are Spiroid1 and Helicon gear drives. The classical gear drives of this type are Archimedean ones. The objective of this study are hyperboloid gear drives with face meshing, when the pinion has threads of conic convolute, Archimedean and involute types, or the pinion has threads of cylindrical convolute, Archimedean and involute types. For simplicity, all three type transmissions with face mating gears and a conic pinion are titled Spiroid and all three type trans- missions with face mating gears and a cylindrical pinion are titled Helicon. Principles of the mathematical modelling of tooth contact synthesis are discussed in Part 1: Basic theoretical and CAD experience of this study. The second part of this article is a brief overview of the innovations and inventions created in this field at the Institute of Mechanics – Bulgarian Academy of Sciences in the last three decades. This study is also dedicated on elaboration of the specialized face gear sets for implementation into bio-robot hand. It is based on the application of 3D software technology, using 3D print for the realization of the physical models of the gear drives.

  1. One Approach to the Synthesis, Design and Manufacture of Hyperboloid Gear Sets With Face Mating Gears. Part 1: Basic Theoretical and Cad Experience

    Abadjiev, Valentin; Abadjieva, Emilia

    2016-06-01

    Hyperboloid gear drives with face mating gears are used to transform rotations between shafts with non-parallel and non-intersecting axes. A special case of these transmissions are Spiroid and Helicon gear drives. The classical gear drives of this type are the Archimedean ones. The objective of this study are hyperboloid gear drives with face meshing, when the pinion possesses threads of conic convolute, Archimedean and involute types, or the pinion has threads of cylindrical convolute, Archimedean and involute types. For simplicity, all three types transmis- sions with face mating gears and a conic pinion are titled Spiroid and all three types transmissions with face mating gears and a cylindrical pinion are titled Helicon. Principles of the mathematical modelling of tooth contact synthesis are discussed in this study. The presented research shows that the synthesis is realized by application of two mathematical models: pitch contact point and mesh region models. Two approaches for synthesis of the gear drives in accordance with Olivier's principles are illustrated. The algorithms and computer programs for optimization synthesis and design of the studied hyperboloid gear drives are presented.

  2. Jakuba Sobieskiego opisanie wyprawy na Moskwę (na podstawie "Diariusza ekspedycyjej moskiewskiej dwuletniej królewica Władysława Anno Domini 1617")

    Borek, Piotr

    2013-01-01

    The essay discusses Jakub Sobieski’s diaries and memories, which belong to the finest specimens of such writing in Polish Baroque. The diary and memoirs of the Moscow campaign of 1617-1618 have survived in only a few copies, with the most important ones in Biblioteka Czartoryskich in Cracow. Reconstruction of Prince Władysław’s struggle for the Russian crown is mostly based on a handwritten testimony called "Diariusz ekspedycyjej moskiewskiej dwuletniej królewica Władysława A. D. 1617" [The D...

  3. Detection and Localization of Tooth Breakage Fault on Wind Turbine Planetary Gear System considering Gear Manufacturing Errors

    Y. Gui

    2014-01-01

    Full Text Available Sidebands of vibration spectrum are sensitive to the fault degree and have been proved to be useful for tooth fault detection and localization. However, the amplitude and frequency modulation due to manufacturing errors (which are inevitable in actual planetary gear system lead to much more complex sidebands. Thus, in the paper, a lumped parameter model for a typical planetary gear system with various types of errors is established. In the model, the influences of tooth faults on time-varying mesh stiffness and tooth impact force are derived analytically. Numerical methods are then utilized to obtain the response spectra of the system with tooth faults with and without errors. Three system components (including sun, planet, and ring gears with tooth faults are considered in the discussion, respectively. Through detailed comparisons of spectral sidebands, fault characteristic frequencies of the system are acquired. Dynamic experiments on a planetary gear-box test rig are carried out to verify the simulation results and these results are of great significances for the detection and localization of tooth faults in wind turbines.

  4. Analysis of effect of random perturbation on dynamic response of gear transmission system

    In order to investigate the effects of random perturbation of a low-frequency excitation caused by torque fluctuations, gear damping ratio, gear backlash, meshing frequency and meshing stiffness, the random dynamic model of a single pair of three-degree-of-freedom spur gear transmission system is established. With gear meshing frequency changing, the dynamic characteristics of the gear transmission system were analyzed by bifurcation diagram, phase diagram, time course diagram and Poincaré map of the system. The effects of random perturbation caused by a low-frequency excitation caused by torque fluctuations, gear damping ratio, gear backlash, meshing frequency and meshing stiffness were comparative analyzed. Numerical simulation shows that the gear transmission system with nonlinear clearance exists rich period-doubling bifurcation phenomenon. With the increasing of the gear meshing frequency, gear transmission system will be from the chaotic motion to periodic motion by inverse period-doubling bifurcation. The effect of the meshing frequency random perturbation on the gear transmission system movement is largest. On the contrary, the effect of the meshing stiffness random perturbation on the system is minimum

  5. Compensation method for the alignment angle error of a gear axis in profile deviation measurement

    In the precision measurement of involute helical gears, the alignment angle error of a gear axis, which was caused by the assembly error of a gear measuring machine, will affect the measurement accuracy of profile deviation. A model of the involute helical gear is established under the condition that the alignment angle error of the gear axis exists. Based on the measurement theory of profile deviation, without changing the initial measurement method and data process of the gear measuring machine, a compensation method is proposed for the alignment angle error of the gear axis that is included in profile deviation measurement results. Using this method, the alignment angle error of the gear axis can be compensated for precisely. Some experiments that compare the residual alignment angle error of a gear axis after compensation for the initial alignment angle error were performed to verify the accuracy and feasibility of this method. Experimental results show that the residual alignment angle error of a gear axis included in the profile deviation measurement results is decreased by more than 85% after compensation, and this compensation method significantly improves the measurement accuracy of the profile deviation of involute helical gear. (paper)

  6. Standard conforming involute gear metrology using an articulated arm coordinate measuring system

    Standard conforming involute gear measurements were taken by a manually operating articulated arm system and the respective task-specific measurement uncertainties were estimated. User-friendly templates were developed to provide almost unambiguous and repeatable measurement results. They allow the metrologist to easily detect and gather the single measurement points according to existing guidelines and standards commonly used in gear metrology. The research activities were carried out at the Physikalisch-Technische Bundesanstalt (PTB), Germany in the Department of Coordinate Metrology. Measurements were taken on a robust and highly accurate large gear measurement standard of PTB, in the following called the gear standard. This gear standard materializes a left-hand and a right-hand gear as well as a spur gear. The 1 m outside diameter of the gear standard is similar to the gears used in wind power plants. A commercial articulated arm coordinate measuring system was used for the measurements. A high temperature stability of ±0.2 °C was provided to minimize thermal influences. The results of profile and helix measurements will be presented. This worldwide first investigation, on the basis of a calibrated involute gear standard, gives users of the articulating arm system quantitative information on a task-specific performance of a representative gear measurement. (paper)

  7. Correlation of Gear Surface Fatigue Lives to Lambda Ratio (Specific Film Thickness)

    Krantz, Timothy Lewis

    2013-01-01

    The effect of the lubrication regime on gear performance has been recognized, qualitatively, for decades. Often the lubrication regime is characterized by the specific film thickness being the ratio of lubricant film thickness to the composite surface roughness. Three studies done at NASA to investigate gearing pitting life are revisited in this work. All tests were done at a common load. In one study, ground gears were tested using a variety of lubricants that included a range of viscosities, and therefore the gears operated with differing film thicknesses. In a second and third study, the performance of gears with ground teeth and superfinished teeth were assessed. Thicker oil films provided longer lives as did improved surface finish. These datasets were combined into a common dataset using the concept of specific film thickness. This unique dataset of more 258 tests provides gear designers with some qualitative information to make gear design decisions.

  8. Experiences of how fishers grab opportunities in (more) free regulation of gear

    Qvist Eliasen, Søren; Mortensen, Lars O.; Ulrich, Clara

    In the Minidisc project 14 vessels fished under conditions corresponding to free choose of gear. Based on the skippers initial idea of gear adjustment and a subsequent interview 6 months later the experiences of the skippers´ choice of “free” gear, the process for adjusting it and the tools for...... evaluating the efficiency and selectivity are discussed. Only incremental development using elements from previous used gear and other fisheries were found. Gear development took place in an interaction between the skipper and trawl maker, while no research was involved. This indicates that free choice of...... gear (under monitored discard ban) would lead to incremental adjustments. Parts of the fleet would have difficulties in evaluating the gear and subsequently optimise by adjusting. This would leave a need for support for development of evaluation procedures, especially among the small vessels. Radical...

  9. Surface Fatigue Lives of Case-Carburized Gears With an Improved Surface Finish

    Krantz, T. L.; Alanou, M. P.; Evans, H. P.; Snidle, R. W.; Krantz, T. L. (Technical Monitor)

    2000-01-01

    Previous research provides qualitative evidence that an improved surface finish can increase the surface fatigue lives of gears. To quantify the influence of surface roughness on life, a set of AISI 93 10 steel gears was provided with a nearmirror finish by superfinishing. The effects of the superfinishing on the quality of the gear tooth surfaces were determined using data from metrology, profilometry, and interferometric microscope inspections. The superfinishing reduced the roughness average by about a factor of 5. The superfinished gears were subjected to surface fatigue testing at 1.71 -GPa (248-ksi) Hertz contact stress, and the data were compared with the NASA Glenn gear fatigue data base. The lives of gears with superfinished teeth were about four times greater compared with the lives of gears with ground teeth but with otherwise similar quality.

  10. Interrelationship between autism diagnostic observation schedule-generic (ADOS-G), autism diagnostic interview-revised (ADI-R), and the diagnostic and statistical manual of mental disorders (DSM-IV-TR) classification in children and adolescents with mental retardation

    de Bildt, A; Sytema, S; Ketelaars, C; Kraijer, D; Mulder, E; Volkmar, F; Minderaa, R

    2004-01-01

    The interrelationship between the Autism Diagnostic Interview-Revised (ADI-R), Autism Diagnostic Observation Schedule-Generic (ADOS-G) and clinical classification was studied in 184 children and adolescents with Mental Retardation (MR). The agreement between the ADI-R and ADOS-G was fair, with a sub

  11. Investigation about crack propagation paths in thin rim gears

    F. Curà

    2014-10-01

    Full Text Available Crack propagation in gears is a problem related not only to the life of the components, but also to the concept of failsafe design. Fail safe design means to design a component in order that, if a failure occurs, this may cause a “safe failure”. This aspect is very important above all in aerospace industry. As a matter of fact, in aerospace application, the need of reducing weight brings to produce gears with very thick rim and web. Considering thin rim gears, when a crack is nucleated near the tooth root, it may propagate through the tooth (causing the loss of the entire tooth or a portion of it or the propagation may follow a path across the wheel diameter (causing the projection of big parts of the gear that may break the gearbox and may cause serious damage to the aircraft. The first failure mode is define as “failsafe failure” and the second one as “catastrophic failure” and of course has to be avoided. Designers need to have robust design criteria in order to predict crack propagation paths and to avoid catastrophic failures. In literature, few works are present concerning this topic, in particular related to the effect of geometrical parameters that may affect the crack propagation. In this work a numerical analysis about crack propagation in gears with respect to the backup ratio (ratio between tooth height and rim thickness, initial crack position and shape has been done by means of the Extended FEM (XFEM technique, realizing 3D models. XFEM 3D is a relatively new technique consisting in enriching traditional finite elements with more complex shape functions; in this way it is possible to propagate crack also between mesh nodes and to have mesh independent results. Aim of this paper is to highlight the crack propagation path in order to give to designers an high confident design criterion, related to the gear geometry. In particular, the effect of both rim thickness and orientation of the initial crack have been considered

  12. Internal examination of CAGR's

    During selected reactor maintenance periods it will be necessary to conduct examinations of reactor internal components to gain assurance of their continuing integrity throughout the design life. Equipment for remote examination is being developed that will measure the distortions of the graphite moderator bricks and extract samples from them for analysis. Other remotely operated equipment will allow closed circuit TV viewing inside the reactors: the equipment provides both wide field and detailed inspection facilities within a single compact unit. Manipulators are being developed to ring the viewing units to the best vantage points. Reeling and handling gear will be operated from outside the vessels and these provide full containment at all times. (author)

  13. Low-rank plus sparse decomposition for exoplanet detection in direct-imaging ADI sequences. The LLSG algorithm

    Gomez Gonzalez, C. A.; Absil, O.; Absil, P.-A.; Van Droogenbroeck, M.; Mawet, D.; Surdej, J.

    2016-04-01

    Context. Data processing constitutes a critical component of high-contrast exoplanet imaging. Its role is almost as important as the choice of a coronagraph or a wavefront control system, and it is intertwined with the chosen observing strategy. Among the data processing techniques for angular differential imaging (ADI), the most recent is the family of principal component analysis (PCA) based algorithms. It is a widely used statistical tool developed during the first half of the past century. PCA serves, in this case, as a subspace projection technique for constructing a reference point spread function (PSF) that can be subtracted from the science data for boosting the detectability of potential companions present in the data. Unfortunately, when building this reference PSF from the science data itself, PCA comes with certain limitations such as the sensitivity of the lower dimensional orthogonal subspace to non-Gaussian noise. Aims: Inspired by recent advances in machine learning algorithms such as robust PCA, we aim to propose a localized subspace projection technique that surpasses current PCA-based post-processing algorithms in terms of the detectability of companions at near real-time speed, a quality that will be useful for future direct imaging surveys. Methods: We used randomized low-rank approximation methods recently proposed in the machine learning literature, coupled with entry-wise thresholding to decompose an ADI image sequence locally into low-rank, sparse, and Gaussian noise components (LLSG). This local three-term decomposition separates the starlight and the associated speckle noise from the planetary signal, which mostly remains in the sparse term. We tested the performance of our new algorithm on a long ADI sequence obtained on β Pictoris with VLT/NACO. Results: Compared to a standard PCA approach, LLSG decomposition reaches a higher signal-to-noise ratio and has an overall better performance in the receiver operating characteristic space

  14. Elderly Adi Women of Arunachal Pradesh: "Living Encyclopedias" and Cultural Refugia in Biodiversity Conservation of the Eastern Himalaya, India

    Singh, Ranjay K.; Rallen, Orik; Padung, Egul

    2013-09-01

    Elderly women of a particular socioecological system are considered to be "living encyclopedias" in biocultural knowledge systems. These women play a pivotal role in retaining and passing on biodiversity-related traditional knowledge to the next generations. Unfortunately the fast changing sociocultural values and the impact of modernity have rendered their knowledge somewhat less valuable and they are being treated as "cultural refugia." Our study on the importance of these women in the conservation of indigenous biodiversity was conducted in 14 randomly selected villages dominated by the Adi tribe of East Siang District, Arunachal Pradesh (northeast India). Data were collected from 531 women (381 elderly and 150 young to middle aged) during 2003-2008 using conventional social science methods and participatory rural appraisal. One innovative method, namely "recipe contest," was devised to mobilize Adi women of each village in order to energies them and explore their knowledge relating to traditional foods, ethnomedicines, and conservation of indigenous biodiversity. Results indicated that 55 plant species are being used by elderly Adi women in their food systems, while 34 plant species are integral parts of ethnomedicinal practices. These women identified different plant species found under multistory canopies of community forests. Elderly women were particularly skilled in preparing traditional foods including beverages and held significantly greater knowledge of indigenous plants than younger women. Lifelong experiences and cultural diversity were found to influence the significance of biodiversity use and conservation. The conservation of biodiversity occurs in three different habitats: jhum lands (shifting cultivation), Morang forest (community managed forests), and home gardens. The knowledge and practice of elderly women about habitats and multistory vegetations, regenerative techniques, selective harvesting, and cultivation practices contribute

  15. Molecular Dynamics Simulation of a Multi-Walled Carbon Nanotube Based Gear

    Han, Jie; Globus, Al; Srivastava, Deepak; Chancellor, Marisa K. (Technical Monitor)

    1997-01-01

    We used molecular dynamics to investigate the properties of a multi-walled carbon nanotube based gear. Previous work computationally suggested that molecular gears fashioned from (14,0) single-walled carbon nanotubes operate well at 50-100 gigahertz. The gears were formed from nanotubes with teeth added via a benzyne reaction known to occur with C60. A modified, parallelized version of Brenner's potential was used to model interatomic forces within each molecule. A Leonard-Jones 6-12 potential was used for forces between molecules. The gear in this study was based on the smallest multi-walled nanotube supported by some experimental evidence. Each gear was a (52,0) nanotube surrounding a (37,10) nanotube with approximate 20.4 and 16,8 A radii respectively. These sizes were chosen to be consistent with inter-tube spacing observed by and were slightly larger than graphite inter-layer spacings. The benzyne teeth were attached via 2+4 cycloaddition to exterior of the (52,0) tube. 2+4 bonds were used rather than the 2+2 bonds observed by Hoke since 2+4 bonds are preferred by naphthalene and quantum calculations by Jaffe suggest that 2+4 bonds are preferred on carbon nanotubes of sufficient diameter. One gear was 'powered' by forcing the atoms near the end of the outside buckytube to rotate to simulate a motor. A second gear was allowed to rotate by keeping the atoms near the end of its outside buckytube on a cylinder. The ends of both gears were constrained to stay in an approximately constant position relative to each other, simulating a casing, to insure that the gear teeth meshed. The stiff meshing aromatic gear teeth transferred angular momentum from the powered gear to the driven gear. The simulation was performed in a vacuum and with a software thermostat. Preliminary results suggest that the powered gear had trouble turning the driven gear without slip. The larger radius and greater mass of these gears relative to the (14,0) gears previously studied requires a

  16. Autism Diagnostic Interview-Revised (ADI-R) Algorithms for Toddlers and Young Preschoolers : Application in a Non-US Sample of 1,104 Children

    de Bildt, Annelies; Sytema, Sjoerd; Zander, Eric; Bölte, Sven; Sturm, Harald; Yirmiya, Nurit; Yaari, Maya; Charman, Tony; Salomone, Erica; LeCouteur, Ann; Green, Jonathan; Bedia, Ricardo Canal; Primo, Patricia García; van Daalen, Emma; de Jonge, Maretha V.; Guðmundsdóttir, Emilía; Jóhannsdóttir, Sigurrós; Raleva, Marija; Boskovska, Meri; Rogé, Bernadette; Baduel, Sophie; Moilanen, Irma; Yliherva, Anneli; Buitelaar, Jan; Oosterling, Iris J.

    2015-01-01

    The current study aimed to investigate the Autism Diagnostic Interview-Revised (ADI-R) algorithms for toddlers and young preschoolers (Kim and Lord, J Autism Dev Disord 42(1):82–93, 2012) in a non-US sample from ten sites in nine countries (n = 1,104). The construct validity indicated a good fit of

  17. Autism Diagnostic Interview-Revised (ADI-R) Algorithms for Toddlers and Young Preschoolers: Application in a Non-US Sample of 1,104 Children

    Bildt, A. de; Sytema, S.; Zander, E.; Bolte, S.; Sturm, H.; Yirmiya, N.; Yaari, M.; Charman, T.; Salomone, E.; LeCouteur, A.; Green, J.; Bedia, R.C.; Primo, P.G.; Daalen, E. van; Jonge, M.V. de; Guethmundsdottir, E.; Johannsdottir, S.; Raleva, M.; Boskovska, M.; Roge, B.; Baduel, S.; Moilanen, I.; Yliherva, A.; Buitelaar, J.; Oosterling, I.J.

    2015-01-01

    The current study aimed to investigate the Autism Diagnostic Interview-Revised (ADI-R) algorithms for toddlers and young preschoolers (Kim and Lord, J Autism Dev Disord 42(1):82-93, 2012) in a non-US sample from ten sites in nine countries (n = 1,104). The construct validity indicated a good fit of

  18. Autism Diagnostic Interview-Revised (ADI-R) Algorithms for Toddlers and Young Preschoolers : Application in a Non-US Sample of 1,104 Children

    de Bildt, Annelies; Sytema, Sjoerd; Zander, Eric; Bolte, Sven; Sturm, Harald; Yirmiya, Nurit; Yaari, Maya; Charman, Tony; Salomone, Erica; LeCouteur, Ann; Green, Jonathan; Canal Bedia, Ricardo; Primo, Patricia Garcia; van Daalen, Emma; de Jonge, Maretha V.; Gudmundsdottir, Emilia; Johannsdottir, Sigurros; Raleva, Marija; Boskovska, Meri; Roge, Bernadette; Baduel, Sophie; Moilanen, Irma; Yliherva, Anneli; Buitelaar, Jan; Oosterling, Iris J.

    2015-01-01

    The current study aimed to investigate the Autism Diagnostic Interview-Revised (ADI-R) algorithms for toddlers and young preschoolers (Kim and Lord, J Autism Dev Disord 42(1):82-93, 2012) in a non-US sample from ten sites in nine countries (n = 1,104). The construct validity indicated a good fit of

  19. Natural convection in a differentially heated rectangular layer solved by an A.D.I. method coupled with compact Hermitian methods of 0<2>-0<4> order

    Boussaid, M. [Institut National de Genie Mecanique, Boumerdes (Algeria); Bouhadef, M. [Algiers Univ. (Algeria). Faculte des Sciences

    1993-12-31

    We study in this article the classical problem of the differentially heated rectangular layer by an O(2)-O(4) order difference method, which is ADI coupled with compact Hermitian method with off-center convection terms, in order to obtain very high Rayleigh numbers (approximately 10 E +11) and for various elongation and tilting layers. (Authors). 8 refs., 7 figs.

  20. Suitability of Alternative Lubricants for Automotive Gear Applications

    Amit Suhane

    2014-03-01

    Full Text Available Rising environmental concerns due to the problems associated with conventional mineral lubricants has renewed interest in usage of alternative resources. Various attempts have been made to explore the possibilities of utilizing vegetable oils for range of applications. Properties like excellent viscosity features, higher biodegradability, lower toxicity, better renewability & natural lubricity etc shows its potential as lubricants inspite of certain technical problems. Critical issues like lower oxidation stability , poor cold temperature properties affects the performance of vegetable oils and restricts its application to limited range . Gear oils are the hidden workhorses of automotive applications. This article highlights the suitability of various vegetable oils for lubricant formulation as an alternative in automotive gearing applications.

  1. Performance evaluation on vibration control of MR landing gear

    This paper is concerned with the applicability of the developed MR damper to the landing gear system for the attenuating undesired shock and vibration in the landing and taxing phases. First of all, the experimental model of the MR damper is derived based on the results of performance evaluations. Next, a simplified skyhook controller, which is one of the most straightforward, but effective approaches for improving ride comport in vehicles with active suspensions, is formulated. Then, the vibration control performances of the landing gear system using the MR damper are theoretically evaluated in the landing phase of the aircraft. A series of simulation analyses show that the proposed MR damper with the skyhook controller is effective for suppressing undesired vibration of the aircraft body. Finally, the effectiveness of the simulation results are additionally verified via HILS (Hardware-in-the-loop-simulation) method.

  2. Vibration isolation based on mass coupling by gear system

    This paper investigates the idea of vibration control through mass coupling and demonstrates this with a simple three mass system coupled together by a gear roller system. The coupling between masses introduces off diagonal terms in the mass matrix. These additional terms are variables and may be utilized in such a way as to eliminate relevant elements of the frequency matrix to obtain zero displacement at the operating frequency. This new found ability for control of non-diagonal elements through the use of a mass coupling therefore forms the back bone of this procedure. The procedure is used to isolate the system at typical operating frequencies by the using the parameters of the gear mechanism. The results showed that such a method can be successful for isolation and the introduction of damping on the system increased the range over which isolation occurred

  3. Topological modeling of a one stage spur gear transmission

    Miladi Chaabane, Mariem; Plateaux, Régis; Choley, Jean-Yves; Karra, Chafik; Riviere, Alain; Haddar, Mohamed

    2014-09-01

    Finding a basis of unification for the modeling of mechatronic systems is the search subject of several works. This paper is a part of a general research designed to the application of topology as a new approach for the modeling of mechatronic systems. Particularly, the modeling of a one stage spur gear transmission using a topological approach is tackled. This approach is based on the concepts of topological collections and transformations and implemented using the MGS(modeling of general systems) language. The topological collections are used to specify the interconnection laws of the one stage spur gear transmission and the transformations are used to specify the local behavior laws of its different components. In order to validate this approach, simulation results are presented and compared with those obtained with MODELICA language using Dymola solver. Since good results are achieved, this approach might be used as a basis of unification for the modeling of mechatronic systems.

  4. Inferring Gear Damage from Oil-Debris and Vibration Data

    Dempsey, Paula

    2006-01-01

    A system for real-time detection of surface-fatigue-pitting damage to gears for use in a helicopter transmission is based on fuzzy-logic used to fuse data from sensors that measure oil-borne debris, referred to as "oil debris" in the article, and vibration signatures. A system to detect helicopter-transmission gear damage is beneficial because the power train of a helicopter is essential for propulsion, lift, and maneuvering, hence, the integrity of the transmission is critical to helicopter safety. To enable detection of an impending transmission failure, an ideal diagnostic system should provide real-time monitoring of the "health" of the transmission, be capable of a high level of reliable detection (with minimization of false alarms), and provide human users with clear information on the health of the system without making it necessary for them to interpret large amounts of sensor data.

  5. Photonic polarization gears for ultra-sensitive angular measurements

    D'Ambrosio, V; Del Re, L; Slussarenko, S; Li, Y; Kwek, L C; Marrucci, L; Walborn, S P; Aolita, L; Sciarrino, F

    2013-01-01

    A key aim in metrology is to find new physical methods for enhancing measurement precision. In this respect, quantum metrology bears great promise, but is unlikely to become practical in the near future. Its ideas can nevertheless provide inspiration for classical methods of immediate value. Here, we demonstrate the generation of NOON-like photonic states of m quanta of angular momentum, with m as high as 100, in a setup that acts as a photonic gear, converting a mechanical rotation of angle {\\theta} into an amplified rotation of the optical polarization by the angle m{\\theta}. Exploiting this effect, we demonstrate angular measurements with a precision comparable to that of the optimal quantum strategy with m photons, but robust to photon losses. The high gear ratio m translates into a similar sensitivity enhancement of optical non-contact angular measurements, boosting the current state-of-the-art by almost two orders of magnitude.

  6. Global behavior of gear system using mixed cell mapping

    SHEN; Yunwen; LIU; Mengjun; DONG; Haijun

    2004-01-01

    In some mechanical nonlinear systems, the transient motion will be undergoing a very long process and the attractor-basin boundaries are so complicated that some difficulties occur in analyzing the system global behavior. To solve this problem a mixed cell mapping method based on the point mapping and the principle of simple cell mapping is developed. The algorithm of the mixed cell mapping is studied. A dynamic model of a gear pair is established with the backlash, damping, transmission error and the time-varying stiffness taken into consideration. The global behaviors of this system are analyzed. The coexistence of the system attractors and the respective attractor-basin of each attractor with different parameters are obtained, thus laying a theoretical basis for improvement of the dynamic behaviors of gear system.

  7. Effect of two synthetic lubricants on life of AISI 9310 spur gears

    Townsend, Dennis P.; Shimski, John

    1991-01-01

    Spur-gear fatigue tests were conducted with two lubricants using a single lot of consumable-electrode vacuum-melted (CVM) AISI 9310 spur gears. The gears were case carburized and hardened to Rockwell C60. The gear pitch diameter was 8.89 cm. The lot of gears was divided into two groups, each of which was tested with a different lubricant. The test lubricants can be classified as synthetic polyol-ester-based lubricants. One lubricant was 30 percent more viscous that the other. Both lubricants have similar pressure viscosity coefficients. Test conditions included a bulk gear temperature of 350 K, a maximum Hertz stress of 1.71 GPa at the pitch line, and a speed of 10,000 rpm. The surface fatigue life of gears tested with one lubricant was approximately 2.4 times that for gears tested with the other lubricant. The lubricant with the 30 percent higher viscosity gave a calculated elastohydrodynamic (EHD) film thickness that was 20 percent higher than the other lubricant. This increased EHD film thickness is the most probable reason for the improvement in surface fatigue life of gears tested with this lubricant over gears tested with the less viscous lubricant.

  8. Use of Protective Gear in Bird Flu Outbreak Response

    2008-12-29

    CDC's Dr. Oliver Morgan discusses how the use of masks and other protective gear impacted whether workers dealing with an outbreak of bird flu in England became sick. The paper is published in the January 2009 issue of CDC’s journal, Emerging Infectious Diseases.  Created: 12/29/2008 by Emerging Infectious Diseases.   Date Released: 12/29/2008.

  9. Stochastic Production and Heterogeneous Risk Preferences: Commercial Fishers’ Gear Choices

    Eggert, Håkan; Tveterås, Ragnar

    2001-01-01

    As long as total effort cannot be completely controlled, a more thorough understanding of fishers’ supply response decisions will be beneficial for fishery managers. In this paper, we present a model of fishers’ gear choice, which is empirically estimated on a panel of Swedish demersal trawlers. The approach allows for heterogeneity both in production technology and in risk preferences. Stochastic revenue functions with fixed effects are estimated and used to predict expected revenue and stan...

  10. Landing Gear Aerodynamic Noise Prediction Using Building-Cube Method

    Daisuke Sasaki; Deguchi Akihito; Hiroshi Onda; Kazuhiro Nakahashi

    2012-01-01

    Landing gear noise prediction method is developed using Building-Cube Method (BCM). The BCM is a multiblock-structured Cartesian mesh flow solver, which aims to enable practical large-scale computation. The computational domain is composed of assemblage of various sizes of building blocks where small blocks are used to capture flow features in detail. Because of Cartesian-based mesh, easy and fast mesh generation for complicated geometries is achieved. The airframe noise is predicted through ...

  11. Bifurcation Analysis of a Nose Landing Gear System

    Tartaruga, Irene; Lowenberg, Mark H.; Cooper, Jonathan E; Sartor, Pia N; Lemmens, Yves

    2016-01-01

    A methodology is proposed to enable the bifurcation analysis of a multi-body nose landing gear (NLG) model by coupling AUTO, a continuation software, to LMS Virtual.Lab Motion, a multi-body software. The approach uses a Singular Value Decomposition (or High Order Singular Value Decomposition) based technique to enable the computation of the stability bounds (e.g. the onset of shimmy) in a very efficient manner. Sensitivity and uncertainty analyses are performed to determine the influence of v...

  12. Numerical continuation applied to landing gear mechanism analysis

    Knowles, J.; Krauskopf, B; Lowenberg, MH

    2010-01-01

    A method of investigating quasi-static mechanisms is presented and applied to an overcentre mechanism and to a nose landing gear mechanism. The method uses static equilibrium equations along with equations describing the geometric constraints in the mechanism. In the spirit of bifurcation analysis, solutions to these steady-state equations are then continued numerically in parameters of interest. Results obtained from the bifurcation method agree with the equivalent results obtained from two ...

  13. STOCHASTIC PRODUCTION AND HETEROGENEOUS RISK PREFERENCES: COMMERCIAL FISHERS' GEAR CHOICE

    Eggert, Hakan; Tveteras, Ragnar

    2001-01-01

    As long as total effort cannot be completely controlled, a more thorough understanding of fishers' supply response decisions will be beneficial for fisheries managers. In this paper, we present a model of fishers' gear choice, which is empirically estimated on a panel of Swedish demersal trawlers. The approach allows for heterogeneity both in production technology and in risk preferences. Stochastic revenue functions with fixed effects are estimated and used to predict expected revenue and st...

  14. Nonlinear Predictive Control of Semi-Active Landing Gear System

    Wu, Dongsu; Gu, Hongbin; Liu, Hui

    2010-01-01

    The application of model predictive control and constructive nonlinear control methodology to semi-active landing gear system is studied in this paper. A unified shock absorber mathematical model incorporates solenoid valve’s electromechanical and magnetic dynamics is built to facilitate simulation and controller design. Then we propose a hierarchical control structure to deal with the high nonlinearity. A dual mode model predictive controller as an outer loop controller is developed to gen...

  15. Tietohallinnon prosessien kehityssuunnitelma COBIT-viitekehysmallilla. CASE: Moventas Gears Oy

    Lähteenmäki, Pasi

    2014-01-01

    Moventas Gears Oy (Moventas) on yksi maailman johtavista teollisuus- ja tuulivoimaturbiini vaihteiden valmistajista. Yhtiö valmistaa voimansiirtoratkaisuja tuulivoima-, sellu-, paperi- ja kaivosteollisuudelle. Moventaksella on noin 900 työntekijää 13 eri maassa sekä maailmanlaajuinen yhteistyökumppaniverkosto. Opinnäytetyön tavoite oli kehittää Moventaksen tietohallinnon prosesseja COBIT viitekehyksen avulla. Tietohallinnon prosessien kehittämisellä on tarkoitus selkeyttää toimintata...

  16. VERIFICATION OF GEAR DYNAMIC MODEL IN DIFFERENT OPERATING CONDITIONS

    Grzegorz PERUŃ

    2014-09-01

    Full Text Available The article presents the results of verification of the drive system dynamic model with gear. Tests were carried out on the real object in different operating conditions. For the same assumed conditions were also carried out simulation studies. Comparison of the results obtained from those two series of tests helped determine the suitability of the model and verify the possibility of replacing experimental research by simulations with use of dynamic model.

  17. Planetary gear profile modification design based on load sharing modelling

    Iglesias, Miguel; Fernández Del Rincón, Alfonso; De-Juan, Ana Magdalena; Garcia, Pablo; Diez, Alberto; Viadero, Fernando

    2015-07-01

    In order to satisfy the increasing demand on high performance planetary transmissions, an important line of research is focused on the understanding of some of the underlying phenomena involved in this mechanical system. Through the development of models capable of reproduce the system behavior, research in this area contributes to improve gear transmission insight, helping developing better maintenance practices and more efficient design processes. A planetary gear model used for the design of profile modifications ratio based on the levelling of the load sharing ratio is presented. The gear profile geometry definition, following a vectorial approach that mimics the real cutting process of gears, is thoroughly described. Teeth undercutting and hypotrochoid definition are implicitly considered, and a procedure for the incorporation of a rounding arc at the tooth tip in order to deal with corner contacts is described. A procedure for the modeling of profile deviations is presented, which can be used for the introduction of both manufacturing errors and designed profile modifications. An easy and flexible implementation of the profile deviation within the planetary model is accomplished based on the geometric overlapping. The contact force calculation and dynamic implementation used in the model are also introduced, and parameters from a real transmission for agricultural applications are presented for the application example. A set of reliefs is designed based on the levelling of the load sharing ratio for the example transmission, and finally some other important dynamic factors of the transmission are analyzed to assess the changes in the dynamic behavior with respect to the non-modified case. Thus, the main innovative aspect of the proposed planetary transmission model is the capacity of providing a simulated load sharing ratio which serves as design variable for the calculation of the tooth profile modifications.

  18. Wearable high-tech gear for homeland security personnel

    Venkateswarlu, Ronda; Hui Wei, Choo; Li Lian, Ngiam; Lim, E. T.; Zhu, Zijian; Yang, Mingjiang

    2006-05-01

    Recent homeland security problems in various countries indicate that fixed surveillance systems at important places are not adequate enough. As the security threats take new dimensions in future, mobile smart security personnel wearing high-tech gear will form the basic infrastructure. See first, listen first, detect first, track first, communicate first with peers, assess the threat and coordinate with security head-quarters are the functions of high-tech gear. This paper proposes a high-tech gear involving (i) hands-free and obtrusion-free textile-based wearable microphone array to capture users voice and interface with body-worn computer, (ii) microphone arrays embedded in textiles to listen and record others voices from a distance, (iii) miniature cameras embedded in the shirt to provide the user with omni vision (iv) wireless personal display as GUI hidden in textile or natural glasses, (v) GPS and body area network for positional awareness for information in the form of text or textile integrated, (vi) reconfigurable HW/SW for all the above functions configured in the form of a usual belt. The main focus of this paper is how to configure the high-tech gear with all these sophisticated functions to disappear into the natural wearables of the user giving him normal look in the public. This project is sponsored by Defence Science & Technology Agency, Ministry of Defence, Singapore. This paper covers multi-discipline technologies at system level, hence not possible to go into details of any subsystem. The main objective of this paper is to share our thoughts and get feedback. Progress and some critical design issues are discussed in this paper.

  19. Planetary Gear Profile Modification Design Based on Load Sharing Modelling

    IGLESIAS Miguel; FERNÁNDEZ DEL RINCÓN Alfonso; DE-JUAN Ana Magdalena; GARCIA Pablo; DIEZ Alberto; VIADERO Fernando

    2015-01-01

    In order to satisfy the increasing demand on high performance planetary transmissions, an important line of research is focused on the understanding of some of the underlying phenomena involved in this mechanical system. Through the development of models capable of reproduce the system behavior, research in this area contributes to improve gear transmission insight, helping developing better maintenance practices and more efficient design processes. A planetary gear model used for the design of profile modifications ratio based on the levelling of the load sharing ratio is presented. The gear profile geometry definition, following a vectorial approach that mimics the real cutting process of gears, is thoroughly described. Teeth undercutting and hypotrochoid definition are implicitly considered, and a procedure for the incorporation of a rounding arc at the tooth tip in order to deal with corner contacts is described. A procedure for the modeling of profile deviations is presented, which can be used for the introduction of both manufacturing errors and designed profile modifications. An easy and flexible implementation of the profile deviation within the planetary model is accomplished based on the geometric overlapping. The contact force calculation and dynamic implementation used in the model are also introduced, and parameters from a real transmission for agricultural applications are presented for the application example. A set of reliefs is designed based on the levelling of the load sharing ratio for the example transmission, and finally some other important dynamic factors of the transmission are analyzed to assess the changes in the dynamic behavior with respect to the non-modified case. Thus, the main innovative aspect of the proposed planetary transmission model is the capacity of providing a simulated load sharing ratio which serves as design variable for the calculation of the tooth profile modifications.

  20. Teaching Planetary Gear Trains with the Aid of Nomographs

    Essam Lauibi Esmail

    2013-01-01

    Planetary gear trains (PGTs) are introduced to undergraduate mechanical engineering students in the course of Theory of Machines. The complexity of the traditional methods for analyzing PGTs has kept many from becoming familiar with the capability of PGTs in mechanisms and machine design. In this paper a unified general formulation for simultaneously visualizing velocities, torques, and power flow through a train is presented on a single nomograph. Therefore, the increasing complex mechanical...