WorldWideScience

Sample records for range gear train

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

    Science.gov (United States)

    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.

  2. 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

    Energy Technology Data Exchange (ETDEWEB)

    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.

  3. Finite Elements Contact Modelling of Planetary Gear Trains

    Science.gov (United States)

    Stoyanov, Svetlin; Dobrev, Vasko; Dobreva, Antoaneta

    2017-10-01

    The paper presents the application aspects of computer technologies concerning the process of creating theoretical contact models of planetary gear trains using Abaqus/Explicit. The necessary assumptions, constrains and specific features of these gear drives are discussed in details. The models created are appropriate and useful tools for computer simulation research of the dynamic behaviour of planetary gear trains.

  4. Preliminary Investigation of the Thermal Behavior of High-Speed Helical Gear Trains

    Science.gov (United States)

    Handschuh, Robert F.; Kilmain, Charles J.

    2002-01-01

    A preliminary experimental investigation of the thermal behavior of high-speed helical gears will be presented. A full-scale torque regenerative test stand has been built to test a representative helical gear train as that used in tiltrotor aircraft. Power loss and temperature data from a wide range of operating conditions were measured. Loop power ranged up to 3730 kW (5000 hp). Drive system components representative of flight quality hardware were used in the test program. The results attained in this initial study indicated that windage losses due to the high rotational speeds that were tested were far more important than the losses due to the gear meshing losses.

  5. Teaching Planetary Gear Trains with the Aid of Nomographs

    Directory of Open Access Journals (Sweden)

    Essam Lauibi Esmail

    2013-01-01

    Full Text Available 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 systems, such as automotive transmissions, are much easier to understand. Nomographs of Fundamental Gear Entities (FGEs are constructed based on the nomographs of their fundamental circuits, without specifying the exact gear dimensions. They are then unified in one system nomograph. Nomographs are promising to provide designers with an efficient tool for the design of geared mechanisms.

  6. Gearing.

    Science.gov (United States)

    1985-12-01

    preform is made and ",’ sintered. The sintered powder- metal preformed part is * 𔃾.*S heated to forging temperature and finished forged. The - hot-formed...translation of the metal occurs in this direction. ibt . However, there is a small sliding component acting along the tooth. If the pitch surfaces of the mating...trademark. The (Ilcason Morks. Rochester, N.Y. 9 Usual form Mitre gear Mitre gear Mtega Crown gear Internal bevel gear Roote cone Pitchangleangl

  7. Gears and gear drives

    CERN Document Server

    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

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

    Science.gov (United States)

    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.

  9. Motor Integrated Permanent Magnet Gear with a Wide Torque-Speed Range

    DEFF Research Database (Denmark)

    Rasmussen, Peter Omand; Matzen, Torben N.; Jahns, T. M.

    2009-01-01

    This paper present a new motor integrated permanent magnet gear with a wide torque-speed range. In the paper a 35 kW permanent magnet motor with a base speed of 4000 rpm and a top speed of 14000 rpm is integrated into a permanent magnetic gear with a gearing ratio of 8.67. The design process...... of the combined unit is described together with a description of the construction of the part for a test model. The unit is unique in the sense that it has superior traction characteristics and a torque density of 130 Nm/l which is more 1.5 times of other reported motor integrated permanent magnet gears. The unit...

  10. Thermal Behavior of High-Speed Helical Gear Trains Investigated

    Science.gov (United States)

    Handschuh, Robert F.

    2003-01-01

    High-speed and heavily loaded gearing are commonplace in the rotorcraft systems employed in helicopter and tiltrotor transmissions. The components are expected to deliver high power from the gas turbine engines to the high-torque, low-speed rotor, reducing the shaft rotational speed in the range of 25:1 to 100:1. These components are designed for high power-to-weight ratios, thus the components are fabricated as light as possible with the best materials and processing to transmit the required torque and carry the resultant loads without compromising the reliability of the drive system. This is a difficult task that is meticulously analyzed and thoroughly tested experimentally prior to being applied on a new or redesigned aircraft.

  11. Operational Influence on Thermal Behavior of High-Speed Helical Gear Trains

    Science.gov (United States)

    Handschuh, Robert F.; Kilmain, Charles J.

    2006-01-01

    An experimental effort has been conducted on an aerospace-quality helical gear train to investigate the thermal behavior of the gear system as many important operational conditions were varied. Drive system performance measurements were made at varying speeds and loads (to 5,000 hp and 15,000 rpm). Also, an analytical effort was undertaken for comparison to the measured results. The influence of the various loss mechanisms from the analysis for this high speed helical gear train gearbox will be presented and compared to the experimental results.

  12. Influence of compressive gear on powerlifting performance: role of blood flow restriction training.

    Science.gov (United States)

    Godawa, Travis M; Credeur, Daniel P; Welsch, Michael A

    2012-05-01

    This study investigated the effects of powerlifting gear on training volume and performance, defined by the squat, bench press, and deadlift. Eighteen powerlifters (18-26 years) were randomized into either a group that trained and competed using compressive gear (CG) or without the gear (NON). Training volume, volume progression, and powerlifting performance were assessed before and after 10 weeks of training. Training volume increased in the first 4 weeks for both groups. Volume lifted for squat and the totals were greater in the CG. There was an increase in squat (19.05 ± 30.97 lb, p = 0.02), deadlift (19.05 ± 21.17 lb, p = 0.001), and the total score (44.00 ± 60.44 lb, p = 0.005) for both the groups. The improvements in squat (CG = 33.85 vs. NON = 5.74, p = 0.07) and totals (CG = 66.59 vs. NON = 23.67, p = 0.15) were greater in the CG. Both groups showed a significant and similar increase in the Wilks scores (+13.54 points, p = 0.03). There was a trend toward greater volume progression in those wearing CG during the initial stages of training. Both the groups significantly improved performance for the squat, and deadlift, and had higher totals, and Wilks scores, indicating significant strength gains. The greater magnitude of improvements in the squat and totals for the CG lifters suggests an ergogenic potential of training with powerlifting gear.

  13. Design of a wearable cable-driven upper limb exoskeleton based on epicyclic gear trains structure.

    Science.gov (United States)

    Xiao, Feiyun; Gao, Yongsheng; Wang, Yong; Zhu, Yanhe; Zhao, Jie

    2017-07-20

    Many countries, including Japan, Italy, and China are experiencing demographic shifts as their populations age. Some basic activities of daily living (ADLs) are difficult for elderly people to complete independently due to declines in motor function. In this paper, a 6-DOF wearable cable-driven upper limb exoskeleton (CABexo) based on epicyclic gear trains structure is proposed. The main structure of the exoskeleton system is composed of three epicyclic gear train sections. This new exoskeleton has a parallel mechanical structure to the traditional serial structure, but is stiffer and has a stronger carrying capacity. The traditional gear transmission structure is replaced with a cable transmission system, which is quieter, and has higher accuracy and smoother transmission. The static workspace of the exoskeleton is large enough to meet the demand of assisting aged and disabled individuals in completing most of their activities of daily living (ADLs).

  14. Experimental Study of the Influence of Speed and Load on Thermal Behavior of High-Speed Helical Gear Trains

    Science.gov (United States)

    Handschuh, R.; Kilmain, C.

    2005-01-01

    An experimental effort has been conducted on an aerospace-quality helical gear train to investigate the thermal behavior of the gear system as speed, load, and lubricant flow rate were varied. Temperature test data from a helical gear train at varying speeds and loads (to 5000 hp and 15000 rpm) was collected using thermocouple rakes and axial arrays. The instrumentation was able to capture the radial and axial expelled lubricant-air environment (fling-off lubricant) that is expelled during the gear meshing process. Effects of operational characteristics are presented.

  15. AN APPLICATION OF MULTICRITERIA OPTIMIZATION TO THE TWO-CARRIER TWO-SPEED PLANETARY GEAR TRAINS

    Directory of Open Access Journals (Sweden)

    Jelena Stefanović-Marinović

    2017-04-01

    Full Text Available The objective of this study is the application of multi-criteria optimization to the two-carrier two-speed planetary gear trains. In order to determine mathematical model of multi-criteria optimization, variables, objective functions and conditions should be determined. The subject of the paper is two-carrier two-speed planetary gears with brakes on single shafts. Apart from the determination of the set of the Pareto optimal solutions, the weighted coefficient method for choosing an optimal solution from this set is also included in the mathematical model.

  16. Method and Device for Speed Change by the Epicyclic Gear Train with Stepped-Planet Gear Set

    Directory of Open Access Journals (Sweden)

    Malashchenko Volodymyr

    2016-08-01

    Full Text Available The article describes new method and device for continuously variable speed change management via compound epicyclic gearing with composite planet gears and closed circuit hydrosystem, when the speed control element is either outer ring gear (annulus or the carrier or sun gear. In each case, the control element connected to closed circuit hydrosystem and can be in motion or immovable depending on the bandwidth of hydrosystem’s regulating throttle. We had held theoretical research and received graphic dependences between velocities of driving, control and driven elements by means of computer programing.

  17. Some structural aspects that are relevant for synthesis of planetary gear trains

    Energy Technology Data Exchange (ETDEWEB)

    Rajasri, I. [Pathfinder Engineering College, Hanamkonda (India); Gupta, A.V.S.S.K.S. [JNTU, Hyderabad (India); Rao, Y.V.D. [BITS-Pilani. Dept. of Mechanical Engineering, Hyderabad (India)

    2012-07-01

    Gear Trains are typically used in various mechanisms including wind turbines and robots to transmit specified motion and/or torque between two or more shafts and wind turbines need drives and overdrives that amplify the speed of turbine shaft and provide high speed at generator shaft. Planetary gear trains (PGT) are compact, easy to build and operate. Therefore PGTs are most suitable for such drives including over drives. Graph theory used in synthesis of the PGTs is also useful to identify various possible structural aspects of the PGTs. Generation of PGTs is followed by the test for isomorphism in PGTs generated. In this context various structural aspects relevant for the synthesis of PGTs is described. (Author)

  18. Random Vibration and Dynamic Analysis of a Planetary Gear Train in a Wind Turbine

    Directory of Open Access Journals (Sweden)

    Jianming Yang

    2016-01-01

    Full Text Available Premature failure of gearboxes is a big challenge facing the wind power industry. It highly depends on fully understanding the embedded dynamics to solve this problem. To this end, this paper investigates the random vibration and dynamics of planetary gear trains (PGTs in wind turbines under the excitation of wind turbulence. The turbulence is represented by the Von Karmon spectrum and implemented by passing white noise through a 2nd-order shaping filter. Then, extra equations are formed and added to the original governing equations of motion. With this augmented equation set, a recursive numerical algorithm based on stochastic Newmark scheme is applied to solve for the statistics of the responses starting from initial conditions. After simulation, the variances of the vibration responses and the dynamic meshing forces at gear meshes are obtained.

  19. Spherical gearing with intermediate ball elements: parameter ranges with a high contact ratio

    Science.gov (United States)

    Gorbenko, M. V.; Gorbenko, T. I.

    2017-02-01

    The paper presents analytical research of the geometry and kinematical parameters of spherical gearing with ball intermediate elements. The main attention is paid to the influence of the offset coefficient on the tooth geometry generation, the contact ratio and the motion transmission angle. Intermediate ball element racetracks on the gear are trochoidal curves on a spherical surface. Two areas for the offset coefficient values providing a high value of the contact ratio - basic trochoid (without offset) and prolate trochoid with abutting racetracks of adjacent ball elements ― were revealed. Analysis of the investigated parameters showed that for power transmission, it is preferable to use spherical gearing without an offset, and for kinematic transmission, it is possible to use profiles with a large offset. The present study allows making a rational choice of geometrical parameters depending on the transmission predestination.

  20. Offset Compound Gear Drive

    Science.gov (United States)

    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.

  1. Hybrid Gear

    Science.gov (United States)

    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.

  2. Multi-Objective Optimization of Two-Stage Helical Gear Train Using NSGA-II

    Directory of Open Access Journals (Sweden)

    R. C. Sanghvi

    2014-01-01

    Full Text Available Gears not only transmit the motion and power satisfactorily but also can do so with uniform motion. The design of gears requires an iterative approach to optimize the design parameters that take care of kinematics aspects as well as strength aspects. Moreover, the choice of materials available for gears is limited. Owing to the complex combinations of the above facts, manual design of gears is complicated and time consuming. In this paper, the volume and load carrying capacity are optimized. Three different methodologies (i MATLAB optimization toolbox, (ii genetic algorithm (GA, and (iii multiobjective optimization (NSGA-II technique are used to solve the problem. In the first two methods, volume is minimized in the first step and then the load carrying capacities of both shafts are calculated. In the third method, the problem is treated as a multiobjective problem. For the optimization purpose, face width, module, and number of teeth are taken as design variables. Constraints are imposed on bending strength, surface fatigue strength, and interference. It is apparent from the comparison of results that the result obtained by NSGA-II is more superior than the results obtained by other methods in terms of both objectives.

  3. Magnetic Gearing Versus Conventional Gearing in Actuators for Aerospace Applications

    Science.gov (United States)

    Puchhammer, Gregor

    2014-01-01

    Magnetic geared actuators (MGA) are designed to perform highly reliable, robust and precise motion on satellite platforms or aerospace vehicles. The design allows MGA to be used for various tasks in space applications. In contrast to conventional geared drives, the contact and lubrication free force transmitting elements lead to a considerable lifetime and range extension of drive systems. This paper describes the fundamentals of magnetic wobbling gears (MWG) and the deduced inherent characteristics, and compares conventional and magnetic gearing.

  4. Gear materials, properties, and manufacture

    National Research Council Canada - National Science Library

    Davis, J. R

    2005-01-01

    ... . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 9 Strength . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 11 Gear Materials . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . ....

  5. Weapons of Mass Destruction Technology Evaluation and Training Range

    Energy Technology Data Exchange (ETDEWEB)

    Kevin Larry Young

    2009-05-01

    The Idaho National Laboratory (INL) has a long history for providing technology evaluation and training for military and other federal level Weapons of Mass Destruction (WMD) response agencies. Currently there are many federal organizations and commercial companies developing technologies related to detecting, assessing, mitigating and protecting against hazards associated with a WMD event. Unfortunately, very few locations exist within the United States where WMD response technologies are realistically field tested and evaluated using real chemical, biological, radiological, nuclear and explosive materials. This is particularly true with biological and radiological hazards. Related to this lack of adequate WMD, multi-hazard technology testing capability is the shortage of locations where WMD response teams can train using actual chemical, biological, and radiological material or highly realistic simulates. In response to these technology evaluation and training needs, the INL has assembled a consortium of subject matter experts from existing programs and identified dedicated resources for the purpose of establishing an all-hazards, WMD technology evaluation and training range. The author describes the challenges associated with creating the all-hazards WMD technology evaluation and training range and lists the technical, logistical and financial benefits of an all-hazards technology evaluation and training range. Current resources and capabilities for conducting all-hazard technology evaluation and training at the INL are identified. Existing technology evaluation and training programs at the INL related to radiological, biological and chemical hazards are highlighted, including successes and lessons learned. Finally, remaining gaps in WMD technology evaluation and training capabilities are identified along with recommendations for closing those gaps.

  6. Gear Tooth Wear Detection Algorithm

    Science.gov (United States)

    Delgado, Irebert R.

    2015-01-01

    Vibration-based condition indicators continue to be developed for Health Usage Monitoring of rotorcraft gearboxes. Testing performed at NASA Glenn Research Center have shown correlations between specific condition indicators and specific types of gear wear. To speed up the detection and analysis of gear teeth, an image detection program based on the Viola-Jones algorithm was trained to automatically detect spiral bevel gear wear pitting. The detector was tested using a training set of gear wear pictures and a blind set of gear wear pictures. The detector accuracy for the training set was 75 percent while the accuracy for the blind set was 15 percent. Further improvements on the accuracy of the detector are required but preliminary results have shown its ability to automatically detect gear tooth wear. The trained detector would be used to quickly evaluate a set of gear or pinion pictures for pits, spalls, or abrasive wear. The results could then be used to correlate with vibration or oil debris data. In general, the program could be retrained to detect features of interest from pictures of a component taken over a period of time.

  7. Fuze Gear Train Efficiency

    Science.gov (United States)

    1981-11-01

    P6.06. S a1.0 POINTIFr .94;11 ALPHA)) -02 .O~ 5 La1. POINTEr a94 AIPHA)) a Pfl.3E S *1.0 P’) INTEF a 94149 AIPHAO a Pnl*h& S v 1.0 POINTirr a .949!. ALPHA...conditions, the point efficiency is computed according to equation 3 (ref E-1), i.e., Cŕ PO INTEF KRA 3IO M-in where, withb Ka lt ny The cycle

  8. Gear materials, properties, and manufacture

    National Research Council Canada - National Science Library

    Davis, J. R

    2005-01-01

    ... . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . vii Introduction to Gear Technology Chapter 1 Basic Understanding of Gears . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1...

  9. Effects on vocal range and voice quality of singing voice training: the classically trained female voice.

    Science.gov (United States)

    Pabon, Peter; Stallinga, Rob; Södersten, Maria; Ternström, Sten

    2014-01-01

    A longitudinal study was performed on the acoustical effects of singing voice training under a given study program, using the voice range profile (VRP). Pretraining and posttraining recordings were made of students who participated in a 3-year bachelor singing study program. A questionnaire that included questions on optimal range, register use, classification, vocal health and hygiene, mixing technique, and training goals was used to rate and categorize self-assessed voice changes. Based on the responses, a subgroup of 10 classically trained female voices was selected, which was homogeneous enough for effects of training to be identified. The VRP perimeter contour was analyzed for effects of voice training. Also, a mapping within the VRP of voice quality, as expressed by the crest factor, was used to indicate the register boundaries and to monitor the acoustical consequences of the newly learned vocal technique of "mixed voice." VRPs were averaged across subjects. Findings were compared with the self-assessed vocal changes. Pre/post comparison of the average VRPs showed, in the midrange, (1) a decrease in the VRP area that was associated with the loud chest voice, (2) a reduction of the crest factor values, and (3) a reduction of maximum sound pressure level values. The students' self-evaluations of the voice changes appeared in some cases to contradict the VRP findings. VRPs of individual voices were seen to change over the course of a singing education. These changes were manifest also in the average group. High-resolution computerized recording, complemented with an acoustic register marker, allows a meaningful assessment of some effects of training, on an individual basis and for groups that comprise singers of a specific genre. It is argued that this kind of investigation is possible only within a focused training program, given by a faculty who has agreed on the goals. Copyright © 2014 The Voice Foundation. Published by Mosby, Inc. All rights reserved.

  10. Heavy-metal contamination on training ranges at the Grafenwoehr Training Area, Germany

    Energy Technology Data Exchange (ETDEWEB)

    Zellmer, S.D.; Schneider, J.F.

    1993-05-01

    Large quantities of lead and other heavy metals are deposited in the environment of weapons ranges during training exercises. This study was conducted to determine the type, degree, and extent of heavy-metal contamination on selected handgun, rifle, and hand-grenade ranges at Grafenwoehr Training Area, Germany. Soil, vegetation, and surface-water samples were collected and analyzed using the inductively-coupled plasma atomic-emission spectroscopy (ICP-AES) method and the toxic characterization leaching procedure (TCLP). The ICP-AES results show that above-normal levels of lead and copper are in the surface soil at the handgun range, high concentrations of lead and copper are in the berm and soil surface at the rifle range, and elevated levels of cadmium and above-normal concentrations of arsenic, copper, and zinc are present in the surface soil at the hand-grenade range. The TCLP results show that surface soils can be considered hazardous waste because of lead content at the rifle range and because of cadmium concentration at the hand-grenade range. Vegetation at the handgun and rifle ranges has above-normal concentrations of lead. At the hand-grenade range, both vegetation and surface water have high levels of cadmium. A hand-held X-ray fluorescence (XRF) spectrum analyzer was used to measure lead concentrations in soils in a field test of the method. Comparison of XRF readings with ICP-AES results for lead indicate that the accuracy and precision of the hand-held XRF unit must improve before the unit can be used as more than a screening tool. Results of this study show that heavy-metal contamination at all three ranges is limited to the surface soil; heavy metals are not being leached into the soil profile or transported into adjacent areas.

  11. Modern gear production

    CERN Document Server

    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

  12. Kinematic geometry of gearing

    CERN Document Server

    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

  13. Modular gear bearings

    Science.gov (United States)

    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.

  14. Detecting gear tooth fracture in a high contact ratio face gear mesh

    Science.gov (United States)

    Zakrajsek, James J.; Handschuh, Robert F.; Lewicki, David G.; Decker, Harry J.

    1995-01-01

    This paper summarized the results of a study in which three different vibration diagnostic methods were used to detect gear tooth fracture in a high contact ratio face gear mesh. The NASA spiral bevel gear fatigue test rig was used to produce unseeded fault, natural failures of four face gear specimens. During the fatigue tests, which were run to determine load capacity and primary failure mechanisms for face gears, vibration signals were monitored and recorded for gear diagnostic purposes. Gear tooth bending fatigue and surface pitting were the primary failure modes found in the tests. The damage ranged from partial tooth fracture on a single tooth in one test to heavy wear, severe pitting, and complete tooth fracture of several teeth on another test. Three gear fault detection techniques, FM4, NA4*, and NB4, were applied to the experimental data. These methods use the signal average in both the time and frequency domain. Method NA4* was able to conclusively detect the gear tooth fractures in three out of the four fatigue tests, along with gear tooth surface pitting and heavy wear. For multiple tooth fractures, all of the methods gave a clear indication of the damage. It was also found that due to the high contact ratio of the face gear mesh, single tooth fractures did not significantly affect the vibration signal, making this type of failure difficult to detect.

  15. Anti-backlash gear bearings

    Science.gov (United States)

    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.

  16. Finite Element Residual Stress Analysis of Planetary Gear Tooth

    Directory of Open Access Journals (Sweden)

    Jungang Wang

    2013-01-01

    Full Text Available 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 influence of residual stress on equivalent stress of addendum, pitch circle, and dedendum of internal and external meshing planetary gear tooth profile is analyzed, according to non-linear contact theory, thermodynamic theory, and finite element theory. The results show that the equivalent stresses of planetary gear at both meshing and nonmeshing surface are significantly and differently reduced by residual stress. The study benefits fatigue cracking analysis and dynamic optimization design of planetary gear train.

  17. Gear bearing drive

    Science.gov (United States)

    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.

  18. Modeling Vibration Intensity of Aircraft Bevel Gears

    Directory of Open Access Journals (Sweden)

    V. V. Golovanov

    2017-01-01

    Full Text Available The subject is the aircraft bevel gears, which are part of the drive systems of gas turbine engines and helicopter transmissions. The article deals with defect specifics of the aircraft conical gears with a circular tooth as compared to the conical gear wheels of general engineering. The finite element method has been used to find by calculation that the main reason for destruction of aircraft bevel gears is a resonant vibration excitation of the gear wheel rim due to its nodal diameter eigenvibrations happened to be within the operating range of the transmission rotation frequencies. A parametric finite element model has been developed. It allows us to investigate the impact of modification parameters of the drive side of gear wheels on the function of the kinematic transmission error at different values of transmitted torque. Using the method of main coordinates, a reduced dynamic model of the bevel gear has been developed to allow simulating the vibration intensity of bevel gears with various parameters of the working profile modification. Within the framework of evaluation test of the dynamic model, amplitude-frequency characteristics have been constructed for the main parameters of transmission oscillations, including vibrational stresses in the teeth space. It is found that modification parameters of the transmission drive side have a significant effect on the vibration intensity of the bevel gears in the entire operating range. The main factor affecting the vibration stress amplitude in the gear wheel is the amplitude of the kinematic error function with the corresponding torque transmitted. The obtained research results can be used when designing the new aircraft drives and modernizing the existing ones. As part of the further development, it is expected to create a technique for recording the damage accumulation in the conical gears, taking into account the typical flight profile of a gas turbine engine or a helicopter.

  19. Estimating Gear Teeth Stiffness

    DEFF Research Database (Denmark)

    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 an individual tooth can be expressed in a linear form assuming that the contact length is constant....

  20. Landing gear noise attenuation

    Science.gov (United States)

    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.

  1. Knowledge of Repetitions Range Affects Force Production in Trained Females

    Directory of Open Access Journals (Sweden)

    Israel Halperin, Saied J. Aboodarda, Fabien A. Basset, David G. Behm

    2014-12-01

    Full Text Available Most studies have examined pacing strategies with cyclical activities (running and cycling. It has been demonstrated that males employ different pacing strategies during repeated maximal voluntary contractions (MVCs dependent upon a known endpoint. Since different fatiguing mechanisms have been identified between the genders, it is not known if females use comparable pacing strategies. The purpose of this study was to examine if informing female subjects regarding the number of MVCs to perform would affect force and electromyography (EMG. Twenty well-trained females completed 3 fatiguing protocols in a randomized order. In the control condition participants were informed they would perform twelve MVCs and then actually completed twelve. In the unknown condition they were not told how many MVCs to perform but were stopped after twelve. In the deception condition they were initially informed to perform 6 MVCs, but after the 6th MVC they were asked to perform a few more MVCs and were stopped after twelve. During the first 6 MVCs, forces in the deception condition were greater compared to the unknown (p = 0.021, ES = 0.65, 5% and control (p = 0.022, ES = 0.42, 3% conditions. No differences were found between conditions in the last 6 MVCs. A main effect for repetitions showed force deficits during the first 6 MVCs (p = 0.000, ES = 1.81, 13% and last 6 MVCs (p = 0.05, ES = 0.34, 3%. No differences were found between conditions in biceps and triceps EMG. However, EMG decreased during the first 6 MVCs for biceps (p = 0.001, ES = 1.0, 14% and triceps (p = 0.001, ES = 0.76, 14% across conditions. No differences were found in the last 6 MVCs. The anticipation of performing fewer MVCs led to increased force, whereas no endpoint led to decreased force production.

  2. 50 CFR 665.227 - Allowable gear and gear restrictions.

    Science.gov (United States)

    2010-10-01

    ... 50 Wildlife and Fisheries 9 2010-10-01 2010-10-01 false Allowable gear and gear restrictions. 665... Fisheries § 665.227 Allowable gear and gear restrictions. (a) Hawaii coral reef ecosystem MUS may be taken only with the following allowable gear and methods: (1) Hand harvest; (2) Spear; (3) Slurp gun; (4...

  3. 50 CFR 665.627 - Allowable gear and gear restrictions.

    Science.gov (United States)

    2010-10-01

    ... 50 Wildlife and Fisheries 9 2010-10-01 2010-10-01 false Allowable gear and gear restrictions. 665... Island Area Fisheries § 665.627 Allowable gear and gear restrictions. (a) Coral reef ecosystem MUS may be taken only with the following allowable gear and methods: (1) Hand harvest; (2) Spear; (3) Slurp gun; (4...

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

    Science.gov (United States)

    2010-10-01

    ... 50 Wildlife and Fisheries 9 2010-10-01 2010-10-01 false Allowable gear and gear restrictions. 665... Fisheries § 665.127 Allowable gear and gear restrictions. (a) American Samoa coral reef ecosystem MUS may be taken only with the following allowable gear and methods: (1) Hand harvest; (2) Spear; (3) Slurp gun; (4...

  5. 50 CFR 665.427 - Allowable gear and gear restrictions.

    Science.gov (United States)

    2010-10-01

    ... 50 Wildlife and Fisheries 9 2010-10-01 2010-10-01 false Allowable gear and gear restrictions. 665... Archipelago Fisheries § 665.427 Allowable gear and gear restrictions. (a) Mariana coral reef ecosystem MUS may be taken only with the following allowable gear and methods: (1) Hand harvest; (2) Spear; (3) Slurp...

  6. Ultrasonic test of highly stressed gear shafts

    Energy Technology Data Exchange (ETDEWEB)

    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.

  7. Self-lubricating gear

    Science.gov (United States)

    Demorest, K. E.

    1969-01-01

    Self-lubricating gear, designed for long term operation in a vacuum at high, low, and ambient temperatures, is constructed of alternating layers of metal and a dry lubricant material, such as polytetrafluoroethylene, with a suitable reinforcing material bonded into a laminated composite unit, which is machined to form a standard gear.

  8. Comparison of the produced and perceived voice range profiles in untrained and trained classical singers

    NARCIS (Netherlands)

    Hunter, Eric J.; Svec, Jan G.; Titze, Ingo R.

    2006-01-01

    Frequency and intensity ranges (in true decibel sound pressure level, 20 mu Pa at 1 m) of voice production in trained and untrained vocalists were compared with the perceived dynamic range (phons) and units of loudness (sones) of the ear. Results were reported in terms of standard voice range

  9. Partial tooth gear bearings

    Science.gov (United States)

    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.

  10. Range of motion, neuromechanical and architectural daptations to plantar flexor stretch training in humans

    DEFF Research Database (Denmark)

    Blazevich, Anthony John; Cannavan, Dale; Waugh, Charlie M

    2014-01-01

    flexor stretches after 3 wk of twice-daily stretch training (4×30-s). No changes were observed in a non-exercising control group (N=9), however stretch training elicited a 19.9% increase in dorsiflexion range of motion (ROM) and 28% increase in passive joint moment at end ROM (N=12). Only a trend toward...

  11. Dynamics of High-Speed Precision Geared Rotor Systems

    Directory of Open Access Journals (Sweden)

    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.

  12. Voice Range Profiles of Singing Students: The Effects of Training Duration and Institution.

    Science.gov (United States)

    Lycke, Hugo; Siupsinskiene, Nora

    2016-01-01

    The aim of the study was to assess differences in voice parameters measured by the physiological voice range profile (VRP) in groups of vocally healthy subjects differentiated by the duration of vocal training and the training institution. Six basic frequency- and intensity-related VRP parameters and the frequency dip of the register transition zone were determined from VRP recordings of 162 females studying in individual singing lessons (1st-5th level) in Dutch, Belgian, English, and French public or private training facilities. Sixty-seven nonsinging female students served as controls. Singing students in more advanced singing classes demonstrated a significantly greater frequency range, particularly at high frequencies, than did first-year students. Students with private training showed a significantly increased mean intensity range in comparison to those in group classes, while students with musical theater training exhibited significantly increased frequency- and intensity-related VRP parameters in comparison to the students with classical training. When compared to nonsingers, all singing student subgroups showed significant increases in all basic VRP parameters. However, the register transition parameter was not influenced by training duration or institution. Our study suggests that the extension of physiological vocal limits might depend on training duration and institution. © 2016 S. Karger AG, Basel.

  13. The cycloid Permanent Magnetic Gear

    DEFF Research Database (Denmark)

    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 regard...

  14. Offset Compound Gear Inline Two-Speed Drive

    Science.gov (United States)

    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.

  15. Documentation of the Range 8C rehabilitation demonstration project at Hohenfels Training Area, West Germany

    Energy Technology Data Exchange (ETDEWEB)

    Zellmer, S.D.; Hinchman, R.R.; Carter, R.P.; Severinghaus, W.D.; Lacey, R.M.; Brent, J.J.

    1987-03-01

    Continued and intensive tactical training for the last 35 years at the Hohenfels Training Area (HTA), Federal Republic of Germany, has resulted in extensive environmental damage and reduced training realism. The US Corps of Engineers Construction Engineering Research Laboratory is developing an Integrated Training Area Management (ITAM) Program for the Seventh Army Training Command for use at HTA. Argonne National Laboratory was asked to assist in one element of the ITAM program, a training range rehabilitation demonstration project. The rehabilitation project was begun in 1986 on a 62-ha watershed that included about 16 ha of meadow with training damage typical of HTA. On the basis of amount of plant ground cover, type and degree of erosion, and soil properties, 10 rehabilitation prescriptions were developed to reestablish plant cover, control erosion, and improve training realism. Prescriptions were installed by a local contractor in September 1986. A monitoring program is under way to determine the effectiveness of this effort. Results and experience gained from this project will be used in the ITAM program and for rehabilitation training courses conducted at HTA.

  16. The study of double flank micro gear roll testing

    Science.gov (United States)

    Liu, Yen-Chih; An, Nai-Chun; Yang, Shu-Han; Yan, Sheng-Zhan; Chen, Shih-Lu

    2011-12-01

    The recent fast development of multifunctional portable electronic devices results in the obvious requirement of micro mechanical components. Due to the popular application of the micro actuators and the micro gearboxes, micro gears become the frequently used micro mechanical component in a small device such as small intelligent robots or dental surgical devices. Metal Industries Research & Development Centre (MIRDC) has successfully developed a small speed reducer that comprises several micro planetary gear trains. The module of this micro planetary gear train is 0.12mm. Since all gears are small, no commercial instrument is available for inspection. How to evaluate the manufacturing quality of micro gears becomes an important issue. This study focuses on the double flank gear rolling test and a specialized apparatus is built referring to the testing requirements in the international standards. The center distance variation during the rolling test is recorded and two indices, the total radial composite deviation and the maximum tooth-to-tooth radial composite deviation, are calculated to evaluate the accuracy grade of the micro gears. Experimental results show that the accuracy of the micro gear made by the cold forging process conforms to grade 7 defined in the ISO 1328-2 while grade 2 is achieved if the JGMA 116-02 is specified.

  17. LSRA with Shuttle main gear

    Science.gov (United States)

    1993-01-01

    A space shuttle landing gear system is visible between the two main landing gear components on this NASA CV-990, modified as a Landing Systems Research Aircraft. The space shuttle landing gear test unit, operated by a high-pressure hydraulic system, allowed engineers to assess and document the performance of space shuttle main and nose landing gear systems, tires and wheel assemblies, plus braking and nose wheel steering performance.

  18. On gear tooth stiffness evaluation

    DEFF Research Database (Denmark)

    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...

  19. Normative voice range profiles in vocally trained and untrained children aged between 7 and 10 years.

    Science.gov (United States)

    Schneider, Berit; Zumtobel, Michaela; Prettenhofer, Walter; Aichstill, Birgitta; Jocher, Werner

    2010-03-01

    Only limited data on normal vocal constitution and vocal capabilities in school-aged children are available. To take better care of children's voices, it might be helpful to know voice ranges and limits of not only vocally trained but also vocally untrained children. Goal of this study was the evaluation of singing voice capabilities of vocally healthy children with different social and vocal/musical backgrounds using voice range profile measurements (VRP). VRP percentiles that reflect constitutional aspects were suggested. In this cross-sectional study, 186 children (aged between seven and 10 years), attending five schools, were included. VRP measurements were performed under field conditions. Interviews and questionnaires regarding vocal strain and vocal training were applied; the answers were used for classification of singing activity and vocal training (KLASAK). All children reached a mean singing voice range of at least two octaves. By using the answers of interviews and questionnaires, the children could be classified according to vocal strain and vocal training. The groups showed no significant differences regarding VRP measurements. In the following step, percentiles were calculated. Twenty-five percent of all children (P25) reached a minimum voice range of almost two octaves, namely, 22 semitones (ST) from 220 to 784 Hz with soft and loud singing. Half of the children (P50) had a voice range of 24 ST (2 octaves), while soft singing and a larger voice range of 26 ST while loud singing. The measurements of third quartile (P75) revealed that 25% of children have even a larger voice range than 29 dB (from 196 Hz/g to 1047 Hz/c3) and can sing at most frequencies louder than 90 dB. P90 demonstrated that 10% of the children can sing even lower or higher than the frequency range between 196 Hz/g and 1319 Hz/e3 analyzed. The voice range seems not to be constrained by social but by voice/musical background: children of vocally/musically encouraged schools had wider

  20. 49 CFR 230.89 - Reverse gear.

    Science.gov (United States)

    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 gear...

  1. Changes in spinal range of motion after a flexibility training program in elderly women

    Directory of Open Access Journals (Sweden)

    Battaglia G

    2014-04-01

    Full Text Available Giuseppe Battaglia,1,2 Marianna Bellafiore,1,2 Giovanni Caramazza,2 Antonio Paoli,3 Antonino Bianco,1,2 Antonio Palma1,2 1Department of Law, Society, and Sport Sciences, University of Palermo, Palermo, Italy; 2Sicilian Regional Sports School of Italian National Olympic Committee (CONI, Sicily, Italy; 3Department of Biomedical Sciences, University of Padova, Padova, Italy Background: Aging-related reduced spinal mobility can interfere with the execution of important functional skills and activities in elderly women. Although several studies have shown positive outcomes in response to spinal flexibility training programs, little is known about the management of sets and repetitions in training protocols. The purpose of this study was to investigate the effects of an 8-week specific and standardized flexibility training program on the range of spinal motion in elderly women. Methods: Participants were recruited in a senior center of Palermo and randomly assigned in two groups: trained group (TG and control group (CG, which included 19 and 18 women, respectively. TG was trained for 8 weeks at two sessions/week. In particular, every session included three phases: warm up (~10 minutes, central period (~50 minutes, and cool down (~10 minutes. CG did not perform any physical activity during the experimental period. Spinal ranges of motion (ROM were measured from neutral standing position to maximum bending position and from neutral standing position to maximum extension position before and after the experimental period, using a SpinalMouse® device (Idiag, Volkerswill, Switzerland. Results: After the training period, TG showed an increase in spinal inclination by 16.4% (P<0.05, in sacral/hip ROM by 29.2% (P<0.05, and in thoracic ROM by 22.5% (P>0.05 compared with CG from maximum extension position to maximum bending position. We did not observe any significant difference in TG's lumbar ROM compared with CG after the training period (P>0.05. Conclusion

  2. Effect of three types of flexibility training on active and passive hip range of motion.

    Science.gov (United States)

    López-Bedoya, J; Vernetta-Santana, M; Robles-Fuentes, A; Ariza-Vargas, L

    2013-06-01

    The aim of this study was to measure the effect of 3 types of flexibility training, hold-relax (HR, N.=9), active isolated stretching (AIS, N.=9) and passive static stretching (PSS, N.=11) on passive and active range of motion of hip flexion after 9 weeks of flexibility training. The subjects were physical education college students (14 men and 15 women) whose ages ranged between 20 and 24 years (age mean 21.79, SD: 2.45). A multigroup pre- post-test design with three experimental groups was used. The range of movement was measured by digitalization of pre-test and post-test images. Significant differences were found among the pre- and post-test for the three groups (P<0.05) on passive range of motion of the hip flexion, although there were no significant post-test differences between experimental groups. However, on the active range of motion of hip flexion there was only significant improvement among the pre-test and post-tests for PSS group (P<0.05). The results suggest that PSS is the best option for the improvement of both active and passive range of motion.

  3. Distribution and Fate of Energetics on DoD Test and Training Ranges: Interim Report 5

    Science.gov (United States)

    2005-04-01

    Military Reservation (MMR) near Falmouth, MA (USA) on Cape Cod . The Training Ranges and Impact Area at Camp Edwards encompass approximately 14,000...were fired until 1997, when a moratorium on artillery and mortar firing was established by the U.S. Environmental Protection Agency (EPA). A compre...Sagamore Lens, a major groundwater recharge 102 Chapter 6 Update on Massachusetts Military Reservation area and the most productive portion of the Cape Cod

  4. Wide-Range Temperature Sensors with High-Level Pulse Train Output

    Science.gov (United States)

    Hammoud, Ahmad; Patterson, Richard L.

    2009-01-01

    Two types of temperature sensors have been developed for wide-range temperature applications. The two sensors measure temperature in the range of -190 to +200 C and utilize a thin-film platinum RTD (resistance temperature detector) as the temperature-sensing element. Other parts used in the fabrication of these sensors include NPO (negative-positive- zero) type ceramic capacitors for timing, thermally-stable film or wirewound resistors, and high-temperature circuit boards and solder. The first type of temperature sensor is a relaxation oscillator circuit using an SOI (silicon-on-insulator) operational amplifier as a comparator. The output is a pulse train with a period that is roughly proportional to the temperature being measured. The voltage level of the pulse train is high-level, for example 10 V. The high-level output makes the sensor less sensitive to noise or electromagnetic interference. The output can be read by a frequency or period meter and then converted into a temperature reading. The second type of temperature sensor is made up of various types of multivibrator circuits using an SOI type 555 timer and the passive components mentioned above. Three configurations have been developed that were based on the technique of charging and discharging a capacitor through a resistive element to create a train of pulses governed by the capacitor-resistor time constant. Both types of sensors, which operated successfully over the wide temperature range, have potential use in extreme temperature environments including jet engines and space exploration missions.

  5. Bevel gear fundamentals and applications

    CERN Document Server

    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.

  6. Range 8C Rehabilitation Demonstration Project, Hohenfels Training Area, Germany: Final report

    Energy Technology Data Exchange (ETDEWEB)

    Zellmer, S.D.; Hinchman, R.R.; Johnson, D.O. (Argonne National Lab., IL (United States). Energy Systems Div.); Severinghaus, W.D. (Corps of Engineers, Champaign, IL (United States)); Brent, J.J. (Army Construction Engineering Research Lab., Champaign, IL (United States))

    1991-11-01

    More than 30 years of intensive and continual tactical training has caused extensive environmental damage at the US Army Hohenfels Training Area in Germany. The Range 8C Rehabilitation Demonstration Project, followed by a three-year monitoring effort, was conducted to develop and evaluate the environmental and economic effectiveness of seven revegetation and four erosion control prescriptions implemented at a 16-ha site. The point-intercept method was used to measure the types and amounts of vegetation established and the changes in the vegetative community during three years of military use on the seven areas treated with revegetation prescriptions. Field observations were made to determine the suitability and durability of four types of erosion control structures. Soil fertility and a source of seed appeared to be the most limiting factors in establishing vegetation, while seedbed preparation had only a minor influence. Grasses appeared to be more resistant to vehicle traffic than did other types of vegetation. Because grassed waterways were used as roads by military vehicles and a system of graded terraces was expensive, these erosion control prescriptions were unsuitable and uneconomical for use on training areas. Low-cost riprap waterbars and porous check dams slowed the velocity of runoff, trapped sediments, and were durable. Recommendations were formulated to improve the environmental and economic effectiveness of future rehabilitation efforts on tactical training areas.

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

    DEFF Research Database (Denmark)

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

    results obtained in gear standards measurement uncertainties are presented. This review also describes the design and development of a new type of master gear: the Gauge Block Gear (GBG).The GBG was developed for the performance verification of CMMs, for the specific task of pitch and chordal tooth......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 guidelines......, in order to give an overview of the improvements achieved in the last 25 years. Special attention is paid to gear metrology on coordinate measuring machines (CMMs). Calibration chains for the major gear geometrical quantities developed by Physikalisch-Technische Bundesanstalt (PTB) as well as their recent...

  8. Actively Controlled Landing Gear for Aircraft Vibration Reduction

    Science.gov (United States)

    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.

  9. APPLICATION OF ASYMMETRIC PROFILE IN GEARINGS WITH ECCENTRIC GEARS

    Directory of Open Access Journals (Sweden)

    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.

  10. 46 CFR 28.885 - Cargo gear.

    Science.gov (United States)

    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 rope...

  11. Qualitative evaluation of general practices developing training for a range of health disciplines.

    Science.gov (United States)

    Hughes, Lesley A

    2014-01-01

    This study adopted an interpretative approach, using focus groups and face-to-face interviews to evaluate the development of a five-year pilot project within general practice. The aim of the project is for these practices to offer training to a range of health disciplines from varying academic levels, develop capacity and provide interprofessional education as part of the learning ethos. Eight consortia are involved in the project, which is funded by the workforce and education directorate and the Deanery of the Yorkshire and Humber Strategic Health Authority. The evaluation was undertaken 18 months into the project, to understand the views and experiences of primary care practitioners and university educationalists, in order to identify achievements and barriers to the project's development. The study revealed positive attitudes towards the project, and that steps are being taken to engage in dialogue with universities to increase student numbers, but progress is slow. Early experiences of student nurses taking up placements in the practices reveal incompatible learning outcomes between what is expected for curriculum and learning opportunities within primary care. A common concern is the impact increased students may pose on existing support structures, and that this may compromise student learning. Concern is evident over self-belief and competencies to teach across professions, and the ambiguity over the learning outcomes for IPE and the training required to support this. It is recommended that a systems theory be adopted to provide strategic planning across clinical and education organisations to ensure that structures of communication, leadership and training adequately meet the aims of the project. The paper will be of interest to practitioners in primary care who may be considering expanding services and training, and to educationalists seeking to allocate students to placements in primary care.

  12. The Effectiveness of Shrouding on Reducing Meshed Spur Gear Power Loss Test Results

    Science.gov (United States)

    Delgado, I. R.; Hurrell, M. J.

    2017-01-01

    Gearbox efficiency is reduced at high rotational speeds due to windage drag and viscous effects on rotating, meshed gear components. A goal of NASA aeronautics rotorcraft research is aimed at propulsion technologies that improve efficiency while minimizing vehicle weight. Specifically, reducing power losses to rotorcraft gearboxes would allow gains in areas such as vehicle payload, range, mission type, and fuel consumption. To that end, a gear windage rig has been commissioned at NASA Glenn Research Center to measure windage drag on gears and to test methodologies to mitigate windage power losses. One method used in rotorcraft gearbox design attempts to reduce gear windage power loss by utilizing close clearance walls to enclose the gears in both the axial and radial directions. The close clearance shrouds result in reduced drag on the gear teeth and reduced power loss. For meshed spur gears, the shrouding takes the form of metal side plates and circumferential metal sectors. Variably positioned axial and radial shrouds are incorporated in the NASA rig to study the effect of shroud clearance on gearbox power loss. A number of researchers have given experimental and analytical results for single spur gears, with and without shrouding. Shrouded meshed spur gear test results are sparse in the literature. Windage tests were run at NASA Glenn using meshed spur gears at four shroud configurations: unshrouded, shrouded (max. axial, max. radial), and two intermediate shrouding conditions. Results are compared to available meshed spur gear power loss data analyses as well as single spur gear data analyses.

  13. Energy efficiency improvement by gear shifting optimization

    Directory of Open Access Journals (Sweden)

    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.

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

    Science.gov (United States)

    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. A MATHEMATICAL MODEL OF CHP 2000 TYPE PROGRESSIVE GEAR

    Directory of Open Access Journals (Sweden)

    Paweł Lonkwic

    2016-12-01

    Full Text Available The project of CHP2000 type progressive gear has been presented in the article. The offered solution from its construction point of view differs from the existing solutions due to the application of Belleville springs packets supporting the braking roller cam and achieving a flexible range of the gear loading. The standard concept of the gear loading within a mathematical and a geometrical model has been presented in the article. The proposed solution can be used in the friction lifts with the loading capacity from 8500 up to 20000 N.

  16. PASSIVE ACOUSTIC MONITORING OF ODONTOCETES IN THE VICINITY OF PUULOA UNDERWATER DETONATION TRAINING RANGE, HAWAII RANGE COMPLEX, OAHU

    Science.gov (United States)

    2016-09-25

    anthropogenic sounds of all types can interfere with those sounds and consequently can have negative effects on marine mammals (Mohl et al. 1999; Carrington...through the center of the range and seaward. The eastern portion of the range and shoreward consists of a hard lava rock/ fossilized coral substrate...anchors on the bottom (Lammers et al. 2008). A-7 Characteristics of the Sensor Technology SQ26-01 hydrophone and EAR energy detectors as shown in

  17. 33 CFR 334.1170 - San Pablo Bay, Calif.; gunnery range, Naval Inshore Operations Training Center, Mare Island...

    Science.gov (United States)

    2010-07-01

    ... range, Naval Inshore Operations Training Center, Mare Island, Vallejo. 334.1170 Section 334.1170... Operations Training Center, Mare Island, Vallejo. (a) The Danger Zone. A sector in San Pablo Bay delineated..., Vallejo, California, will conduct gunnery practice in the area during the period April 1 through September...

  18. SELECTED GEARS CUTTING METHODS DEVELOPMENT

    Directory of Open Access Journals (Sweden)

    Stanisław PŁONKA

    2015-06-01

    Full Text Available The paper presents a somewhat extended approach to the cutting tools classification. After that authors present results of the research concerning the form – grinding of spur gears with helical teeth. The modern gear – grinding machine Rapid 900 of HOEFLER is described and results of the accuracy and surface roughness researches are given. Then an example is given, based on references, of the bevel spherical involute, gears cutting, illustrating the development from the cutting of very large straight bevel gears based on the double tracing method suitable for old template – type bevel gear planers to the modern approach using CNC milling machine (3 or 4axis controlled, the principle of Free Form Surfaces cutting.

  19. David Brown gear industries generates world first in swing racks

    Energy Technology Data Exchange (ETDEWEB)

    1987-09-01

    Discusses the gear construction and design of draglines in operation in South Africa. each of the 21 draglines in operation has on average sets of 80 gears ranging from 400 mm to 4 m in diameter. Of these, the largest single unit is the swing rack or ring gear, which on the largest draglines in South Africa is 11.8 m in diameter with teeth of 127 mm circular pitch. The swing rack allows smooth rotational movement of the superstructure, boom and bucket of the dragline. Discusses the cutting of a swing rack for the B-E 1570 at New Vaal with involute profile to a pitch accuracy two grades higher on the AGMA scale than achieved by the previous method of manufacture. The swing rack was cut by David Brown Gear Industries on its 390 ton 14 metre MAAG plano-generator at Benoni. Discusses the accuracy achieved in the cutting and the importance of accuracy for smooth operation and long life. Describes the development of local capability for manufacturing high quality gears and how this should defeat pirates supplying components who win orders on lower price and quicker delivery. Describes other applications in the mining industry of gears supplied by DBGI including the Radicon worm gearbox frequently used on belt conveyors, worm gears for vertical spindle mills for coal crushing; and reduction mills for ESCOM's power stations.

  20. Correlation of Gear Surface Fatigue Lives to Lambda Ratio (Specific Film Thickness)

    Science.gov (United States)

    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.

  1. analysis of gear milling at vari gear milling at various gear milling

    African Journals Online (AJOL)

    eobe

    feedrates for cutting a tooth ing a tooth ing a tooth of a spur gear. Thus, as of a spur gear. Thus, as. The model will serve as a useful tool in prepar. Keywords: Cutting speed, feedrate, time. 1. INTRODUCTION. INTRODUCTION. INTRODUCTION. In milling, a multi-toothed cutter, rotating at a fi position on the machine, shapes ...

  2. Analysis of justification for applying two gear sets within the universal gear reducers

    OpenAIRE

    Rackov Milan; Kuzmanović Siniša; Knežević Ivan; Čavić Maja; Penčić Marko

    2017-01-01

    In the area of universal gear reducers, standard does not prescribe relations between load capacity, gear ratios and axis heights. Therefore, larger load capacity of some gear reducers manufacturers has advantage for lower gear ratio and, vice versa, smaller load capacity of the gearbox achieves higher values of gear ratio. However, there are some manufacturers who produce gear reducers with smaller or larger load capacity for higher or lower gear ratio, within the same axis height. This pape...

  3. Kinematic synthesis of bevel-gear-type robotic wrist mechanisms

    Science.gov (United States)

    Lin, Chen-Chou

    Bevel-gear-type robotic wrist mechanisms are commonly used in industry. The reasons for their popularity are that they are compact, light-weight, and relatively inexpensive. However, there are singularities in their workspace, which substantially degrade their manipulative performance. The objective of this research is to develop an atlas of three-degree-of-freedom bevel-gear-type wrist mechanisms, and through dimensional synthesis to improve their kinematic performance. The dissertation contains two major parts: the first is structural analysis and synthesis, the other is kinematic analysis and dimensional synthesis. To synthesize the kinematic structures of bevel-gear-type wrist mechanisms, the kinematic structures are separated from their functional considerations. All kinematic structures which satisfy the mobility condition are enumerated in an unbiased, systematic manner. Then the bevel-gear-type wrist mechanisms are identified by applying the functional requirements. Structural analysis shows that a three-degree-of-freedom wrist mechanism usually consists of non-fractionated, two degree-of-freedom epicyclic gear train jointed with the base link. Therefore, the structural synthesis can be simplified into a problem of examining the atlas of non-fractionated, two-degree-of-freedom epicyclic gear trains. The resulting bevel-gear-type wrist mechanism has been categorized and evaluated. It is shown that three-degree-of-freedom, four-jointed wrist mechanisms are promising for further improving the kinematic performance. It is found that a spherical planetary gear train is necessarily imbedded in a three-degree-of-freedom, four-jointed wrist mechanism. Therefore, to study the workspace and singularity problems of three-degree-of-freedom four-jointed spherical wrist mechanisms, we have to study the trajectories of spherical planetary gear trains. The parametric equations of the trajectories and some useful geometric properties for the analysis and synthesis of

  4. Rigid MATLAB drivetrain model of a 500 kW wind turbine for predicting maximum gear tooth stresses in a planetary gearbox using multibody gear constraints

    DEFF Research Database (Denmark)

    Jørgensen, Martin Felix; Pedersen, Niels Leergaard; Sørensen, Jens Nørkær

    2014-01-01

    multiple planetary gears are not taken into account. Finite Element Method (FEM) calculations show that when the wind turbine runs close to the maximum wind speed, the maximum gear tooth stress is in the range of 500–700 MPa, which is considered to be realistic using a “worst-case” method. The presented......The aeroelastic FLEX 5 code and a semi-advanced rigid multibody model has been utilized for simulating drivetrain forces and moments in a real 500 kW wind turbine. Experimental validation is carried out with results based on known physical properties of the blades, tower, hub, gearbox, shaft...... for not only transferring torque but also for calculating the gear tooth and internal body reaction forces. The method is appropriate for predicting gear tooth stresses without considering all the complexity of gear tooth geometries. This means that, e.g. gear tooth load-sharing and load-distribution among...

  5. Engineering analysis and test results of the pre-stage planetary gear trains for wrist rotation and pitch assembly and azimuth and elevation assembly of the extendable stiff arm manipulator kit assembly

    Science.gov (United States)

    Morris, R. N.

    1973-01-01

    In order to improve the performance capability of the Extendable Stiff Arm Manipulator (ESAM) it was necessary to increase the overall gear ratio by a factor of approximately four. This is accomplished with minimum effect to existing hardware by the interposition of a planetary gear transmission between the respective drive motors and the harmonic drive transmissions. The engineering analysis in support of this design approach and the subsequent no-load test results are reported.

  6. EFFECTIVENESS OF ECCENTRIC TRAINING, DYNAMIC RANGE OF MOTION EXERCISES AND STATIC STRETCHING ON FLEXIBILITY OF HAMSTRING MUSCLE AMONG FOOTBALL PLAYERS.

    Directory of Open Access Journals (Sweden)

    Askar P.V

    2015-12-01

    Full Text Available Background: Hamstring stretch is an important part of treatment programs aimed at decreasing the likelihood of hamstring injury. Few studies have examine the effect of eccentric training, static stretching and dynamic range of motion(DROM exercise in improving hamstring flexibility this study compares the effect of eccentric training and static stretching in improving hamstring flexibility. The purpose of this study was to determine the effects of Eccentric training, Static stretching and Dynamic range of motion (DROM exercise in improving hamstring flexibility and the second objective is find which technique is more effective in improving hamstring flexibility when compared with a control group. Study design is Experimental pre-test post-test design. Methods: 88 male subjects with limited hamstring flexibility were recruited for this study were assigned to four group. Group1 received eccentric training, group2 received dynamic range of motion exercise, group3 received static stretching and group4 was served as control group. Hamstring length was measured pre intervention and post intervention using a self-monitored active knee extension test. Results: Eccentric training, static stretching and dynamic range of motion exercise showed a significant increase in hamstring length between pre and post intervention. Following a between group analysis done by independent t test revealed a significant difference between group1 group2 and group3 Conclusion: It is concluded that eccentric training, dynamic range of motion (DROM exercise and static stretching groups improved hamstring flexibility.

  7. Remote sensing training needs in professional forest and range resource management curricula

    Science.gov (United States)

    Meyer, M. P.

    1981-01-01

    The status of remote sensing training in accredited U.S. forestry schools is reviewed. It is noted that there is a serious lack of emphasis on aerial photography and aerial photointerpretation in the current curricula. This lack of training at the professional school limits entering employee capability and necessitates expensive on-the-job training.

  8. 50 CFR 648.123 - Gear restrictions.

    Science.gov (United States)

    2010-10-01

    ... limited to, nets, net strengtheners, ropes, lines, or chafing gear, on the top of the regulated portion of... 50 Wildlife and Fisheries 8 2010-10-01 2010-10-01 false Gear restrictions. 648.123 Section 648.123... § 648.123 Gear restrictions. (a) Trawl vessel gear restrictions—(1) Minimum mesh size. No owner or...

  9. 29 CFR 1918.54 - Rigging gear.

    Science.gov (United States)

    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 from...

  10. 50 CFR 648.84 - Gear-marking requirements and gear restrictions.

    Science.gov (United States)

    2010-10-01

    ... 50 Wildlife and Fisheries 8 2010-10-01 2010-10-01 false Gear-marking requirements and gear... Management Measures for the NE Multispecies and Monkfish Fisheries § 648.84 Gear-marking requirements and gear restrictions. (a) Bottom-tending fixed gear, including, but not limited to, gillnets and longlines...

  11. Modelling the Meshing of Cycloidal Gears

    Directory of Open Access Journals (Sweden)

    Nachimowicz Jerzy

    2016-06-01

    Full Text Available Cycloidal drives belong to the group of planetary gear drives. The article presents the process of modelling a cycloidal gear. The full profile of the planetary gear is determined from the following parameters: ratio of the drive, eccentricity value, the equidistant (ring gear roller radius, epicycloid reduction ratio, roller placement diameter in the ring gear. Joong-Ho Shin’s and Soon-Man Kwon’s article (Shin and Know, 2006 was used to determine the profile outline of the cycloidal planetary gear lobes. The result was a scatter chart with smooth lines and markers, presenting the full outline of the cycloidal gear.

  12. The effects of frequency range, vowel, dynamic loudness level, and gender on nasalance in amateur and classically trained singers.

    Science.gov (United States)

    Jennings, Jori Johnson; Kuehn, David P

    2008-01-01

    This study addresses two questions: (1) How much nasality is present in classical Western singing? (2) What are the effects of frequency range, vowel, dynamic level, and gender on nasality in amateur and classically trained singers? The Nasometer II 6400 by KayPENTAX (Lincoln Park, NJ) was used to obtain nasalance values from 21 amateur singers and 25 classically trained singers while singing an ascending five-tone scalar passage in low, mid, and high frequency ranges. Each subject sang the scalar passage at both piano and mezzo-forte dynamic loudness levels on each of the five cardinal vowels (/a/, /e/, /i/, /o/, /u/). A repeated mixed-model analysis indicated a significant main effect for the amateur/classically trained distinction, dynamic loudness level, and vowel, but not for frequency range or gender. The amateur singers had significantly higher nasalance scores than classically trained singers in all ranges and on all vowels except /o/. Dynamic loudness level had a significant effect on nasalance for all subject groups except for female majors in the mid- and high-frequency ranges. The vowel, /i/, received significantly higher nasalance than all of the other vowels. Although results of this study show that dynamic loudness level, vowel, and level of training in classical singing have a significant effect on nasality, nasalance scores for most subjects were relatively low. Only six of the subjects, all of whom were amateur singers, had average nasalance scores that could be considered hypernasal (ie, a nasalance average of 22 or above).

  13. Modelling of teeth of a gear transmission for modern manufacturing technologies

    Science.gov (United States)

    Monica, Z.; Banaś, W.; Ćwikla, G.; Topolska, S.

    2017-08-01

    The technological process of manufacturing of gear wheels is influenced by many factors. It is designated depending on the type of material from which the gear is to be produced, its heat treatment parameters, the required accuracy, the geometrical form and the modifications of the tooth. Therefor the parameters selection process is not easy and moreover it is unambiguous. Another important stage of the technological process is the selection of appropriate tools to properly machine teeth in the operations of both roughing and finishing. In the presented work the focus is put first of all on modern production methods of gears using technologically advanced instruments in comparison with conventional tools. Conventional processing tools such as gear hobbing cutters or Fellows gear-shaper cutters are used from the beginning of the machines for the production of gear wheels. With the development of technology and the creation of CNC machines designated for machining of gears wheel it was also developed the manufacturing technology as well as the design knowledge concerning the technological tools. Leading manufacturers of cutting tools extended the range of tools designated for machining of gears on the so-called hobbing cutters with inserted cemented carbide tips. The same have be introduced to Fellows gear-shaper cutters. The results of tests show that is advantaged to use hobbing cutters with inserted cemented carbide tips for milling gear wheels with a high number of teeth, where the time gains are very high, in relation to the use of conventional milling cutters.

  14. Regular Aerobic Training Combined with Range of Motion Exercises in Juvenile Idiopathic Arthritis

    Directory of Open Access Journals (Sweden)

    Mine Doğru Apti

    2014-01-01

    Full Text Available Objective. To assess the effects of regular aerobic training combined with range of motion (ROM exercises on aerobic capacity, quality of life, and function in children with juvenile idiopathic arthritis (JIA. Methods. Thirty patients with JIA and 20 healthy age-matched controls (mean age ± SD, 11.3 ± 2.4 versus 11.0 ± 2.3, resp.; P>0.05 were included. All patients performed aerobic walking (4 days a week for 8 weeks and active and passive ROM exercises of involved joints. All patients completed the childhood health assessment questionnaire (CHAQ and the child health questionnaire. ROM measurements of joints were performed by using universal goniometer. Aerobic capacity was determined by measuring peak oxygen uptake (VO2peak during an incremental treadmill test. Results. Peak oxygen uptake and exercise duration were significantly lower in JIA group than in controls (32.5 ± 6.6 versus 35.9 ± 5.8 and 13.9 ± 1.9 versus 15.0 ± 2.0, resp.; P<0.05 for both. Eight-week combined exercise program significantly improved exercise parameters of JIA patients (baseline versus postexercise VO2peak and exercise duration, 32.5 ± 6.6 to 35.3 ± 7.9 and 13.9 ± 1.9 to 16.3 ± 2.2, resp.; P<0.001 for both. Exercise intervention significantly improved CHAQ scores in JIA patients (0.77 ± 0.61 to 0.20 ± 0.28, P<0.001. Conclusion. We suggest that regular aerobic exercise combined with ROM exercises may be an important part of treatment in patients with JIA.

  15. USAREUR Local Training Areas (LTAs). Integrated Training Area Management (ITAM) FY09 Status Report: Sustainable Range Program (SRP)

    Science.gov (United States)

    2010-03-01

    project methodology and cost estimate, each project has a description, Benefits to Training, Impact if Not Funded, and a graphics page that...form of large waterlogged hollows from M1 tanks and other heavy vehicle usage. Because it is located in a forested area that lacks adequate direct...the west side of Poedeldorf LTA becomes flooded on either side, and the trail itself becomes waterlogged , because of a lack of drainage ditches

  16. The muscular flexibility training and the range of movement improvement: a critical literature review

    Directory of Open Access Journals (Sweden)

    L.F. Coelho

    2008-01-01

    Full Text Available The muscular flexibility training put in evidence a train of neurophysiological principals and an intricate amount of muscular and viscous-elastic properties. There are a lot of stretching methods, used on the clinical and sport contexts. Despite its common utilization, it isn’t usual the health and educational professionals reflect about the compounds and efficacy of the diverse stretching methods. In this article, we realize a critical review about the diverse methods used on the flexibility training, as the principles and parameters related with that. We will done special emphasis to the principles of the proprioceptive neuromuscular facilitation and the diverse local relaxation methods, like warming. We will also have in count the revealing data relating to the Elasticity Coefficient paradox, witch can help to conceive an intervention philosophy of the flexibility training different from what it have being defended and practiced.

  17. The muscular flexibility training and the range of movement improvement: a critical literature review

    Directory of Open Access Journals (Sweden)

    Luís Filipe dos Santos Coelho

    2007-12-01

    Full Text Available The muscular flexibility training put in evidence a train of neurophysiological principals and an intricate amount of muscular and viscous-elastic properties. There are a lot of stretching methods, used on the clinical and sport contexts. Despite its common utilization, it isn’t usual the health and educational professionals reflect about the compounds and efficacy of the diverse stretching methods. In this article, we realize a critical review about the diverse methods used on the flexibility training, as the principles and parameters related with that. We will done special emphasis to the principles of the proprioceptive neuromuscular facilitation and the diverse local relaxation methods, like warming. We will also have in count the revealing data relating to the Elasticity Coefficient paradox, witch can help to conceive an intervention philosophy of the flexibility training different from what it have being defended and practiced.

  18. The muscular flexibility training and the range of movement improvement: A critical literature review

    Directory of Open Access Journals (Sweden)

    Luís Filipe dos Santos Coelho

    2008-12-01

    Full Text Available The muscular flexibility training put in evidence a train of neurophysiological principals and an intricate amount of muscular and viscous-elastic properties. There are a lot of stretching methods, used on the clinical and sport contexts. Despite its common utilization, it isn’t usual the health and educational professionals reflect about the compounds and efficacy of the diverse stretching methods. In this article, we realize a critical review about the diverse methods used on the flexibility training, as the principles and parameters related with that. We will done special emphasis tothe principles of the proprioceptive- neuromuscular facilitation and the diverse local relaxation methods, like warming. We will also have incount the revealing data relating tothe Elasticity Coefficient paradox, which can help to conceive an intervention philosophy of the flexibility training different from what it have being defended and practiced.

  19. Theory of gearing kinematics, geometry, and synthesis

    CERN Document Server

    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

  20. Advanced Face Gear Surface Durability Evaluations

    Science.gov (United States)

    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.

  1. Coherent lidar modulated with frequency stepped pulse trains for unambiguous high duty cycle range and velocity sensing in the atmosphere

    DEFF Research Database (Denmark)

    Lindelöw, Per Jonas Petter; Mohr, Johan Jacob

    2007-01-01

    Range unambiguous high duty cycle coherent lidars can be constructed based on frequency stepped pulse train modulation, even continuously emitting systems could be envisioned. Such systems are suitable for velocity sensing of dispersed targets, like the atmosphere, at fast acquisition rates...

  2. Advanced theories of hypoid gears

    CERN Document Server

    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

  3. Effects of Climate Change and Urban Development on Army Training Capabilities: Firing Ranges and Maneuver Areas

    Science.gov (United States)

    2016-08-01

    51 8 Soil resiliency and vegetation recovery values for five CONUS installations. The proposed multiplicative value is calculated...dividing the sum of the soil resiliency and vegetation recovery values by 10...listing of threatened and/or endangered spe- cies (TES) or their habitats can also result in the reduction of training area footprints and/or the time

  4. THE EFFECTS OF BACK EXTENSION TRAINING ON BACK MUSCLE STRENGTH AND SPINAL RANGE OF MOTION IN YOUNG FEMALES

    Directory of Open Access Journals (Sweden)

    Yıldız Yaprak

    2013-04-01

    Full Text Available The objective of this study was to determine the effects of a 10-week dynamic back extension training programme and its effects on back muscle strength, back muscle endurance and spinal range of motion (ROM for healthy young females. Seventy-three young females (age: 19.32±1.80 years, height: 158.89±4.71 cm, body weight: 55.67±6.30 kg volunteered for the study. Prior to the training period, all participants completed anthropometric measurements, back muscle strength and endurance test, lateral bending and spinal ROM measurements. After measurements, the participants were divided into two groups. The exercise group (N:35 performed the dynamic back extension exercise 3 days per week for 10 weeks. The control group (N:38 did not participate in any type of exercise. The mixed design ANOVA (group x time was used to determine the difference in pre- and post-training values. The present findings show that there were significant differences between pre-training and post-training values for back muscle strength and spinal ROM in the exercise group. Following the dynamic strength training programme, back muscle strength and spine ROM values except flexion of the lumbar 5-sacrum 1 (L5-S1 segment of the exercise group showed a significant increase when compared with the pre test values. The control group did not show any significant changes when compared with the pre-training values. The results demonstrate that the 10-week dynamic strength training programme was effective for spinal extension ROM and back muscle strength, but there was no change in back muscle endurance. In this context, this programme could potentially be used to prevent the decrease of spinal ROM as well as provide an increase in the fitness parameters of healthy individuals.

  5. The Effectiveness of Shrouding on Reducing Meshed Spur Gear Power Loss - Test Results

    Science.gov (United States)

    Delgado, I. R.; Hurrell, M. J.

    2017-01-01

    Gearbox efficiency is reduced at high rotational speeds due to windage drag and viscous effects on rotating, meshed gear components. A goal of NASA aeronautics rotorcraft research is aimed at propulsion technologies that improve efficiency while minimizing vehicle weight. Specifically, reducing power losses to rotorcraft gearboxes would allow gains in areas such as vehicle payload, range, mission type, and fuel consumption. To that end, a gear windage rig has been commissioned at NASA Glenn Research Center to measure windage drag on gears and to test methodologies to mitigate windage power losses. One method used in rotorcraft gearbox design attempts to reduce gear windage power loss by utilizing close clearance walls to enclose the gears in both the axial and radial directions. The close clearance shrouds result in reduced drag on the gear teeth, and reduced power loss. For meshed spur gears, the shrouding takes the form of metal side plates and circumferential metal sectors. Variably positioned axial and radial shrouds are incorporated in the NASA rig to study the effect of shroud clearance on gearbox power loss. A number of researchers have given experimental and analytical results for single spur gears, with and without shrouding. Shrouded meshed spur gear test results are sparse in the literature. Windage tests were run at NASA Glenn using meshed spur gears at four shroud configurations: unshrouded, shrouded (max. axial, max radial), and two intermediate shrouding conditions. Results are compared to available meshed spur gear power loss data analyses as well as single spur gear data/analyses. Recommendations are made for future work.

  6. Analysis of Wear Behavior of Graphene OXIDE — Polyamide Gears for Engineering Applications

    Science.gov (United States)

    Rajamani, Geetha; Paulraj, Jawahar; Krishnan, Kanny

    Recent advances in polymer nanocomposites open a wide range of applications in various industrial sectors. Due to their high potential properties, these materials are replacing the usage of metals for many heavier components in automobile industries. In this experimental work, the tribological performance of Graphene oxide (GO) — Polyamide is investigated against pristine polyamide by fabricating gears for the usage in engineering applications. A gear test rig was developed in-house for analysis to study the specific wear rate and temperature gradient at different conditions of load and speeds. The wear resistance of the polyamide gears with the addition of 0.03wt.% of graphene oxide is better than the pristine polyamide gears and the specific wear rate is reduced significantly. The reduced specific wear rate of these polymer nanocomposite gears is attributed to the superior properties of graphene oxide such as High specific surface area, good adhesion properties and enhanced glass transition temperatures. The GO nanocomposite gear seems to be a potential alternative against conventional gears for engineering applications. Finally, the wear mechanisms and the potential of GO-based polyamide nanocomposite gears were proposed tentatively in the development of transmission gears for engineering applications.

  7. Baseline Experimental Results on the Effect of Oil Temperature on Shrouded Meshed Spur Gear Windage Power Loss

    Science.gov (United States)

    Delgado, Irebert R.; Hurrell, Michael

    2017-01-01

    Rotorcraft gearbox efficiencies are reduced at increased surface speeds due to viscous and impingement drag on the gear teeth. This windage power loss can affect overall mission range, payload, and frequency of transmission maintenance. Experimental and analytical studies on shrouding for single gears have shown it to be potentially effective in mitigating windage power loss. Efficiency studies on unshrouded meshed gears have shown the effect of speed, oil viscosity, temperature, load, lubrication scheme, etc. on gear windage power loss. The open literature does not contain experimental test data on shrouded meshed spur gears. Gear windage power loss test results are presented on shrouded meshed spur gears at elevated oil inlet temperatures and constant oil pressure both with and without shrouding. Shroud effectiveness is compared at four oil inlet temperatures. The results are compared to the available literature and follow-up work is outlined.

  8. Design and construction of permanent magnetic gears

    DEFF Research Database (Denmark)

    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 mech...

  9. 50 CFR 648.104 - Gear restrictions.

    Science.gov (United States)

    2010-10-01

    ..., lines, or chafing gear, on the top of the regulated portion of a trawl net; except that, one splitting... 50 Wildlife and Fisheries 8 2010-10-01 2010-10-01 false Gear restrictions. 648.104 Section 648.104... Flounder Fisheries § 648.104 Gear restrictions. (a) General. (1) Otter trawlers whose owners are issued a...

  10. 50 CFR 648.23 - Gear restrictions.

    Science.gov (United States)

    2010-10-01

    ... gear, on the top of the regulated portion of a trawl net that results in an effective mesh opening of... 50 Wildlife and Fisheries 8 2010-10-01 2010-10-01 false Gear restrictions. 648.23 Section 648.23... Mackerel, Squid, and Butterfish Fisheries § 648.23 Gear restrictions. (a) Mesh restrictions and exemptions...

  11. Tooth bending fatigue failures in gears

    CSIR Research Space (South Africa)

    Fernandes, PJL

    1996-09-01

    Full Text Available . Like all mechanical components, gears can and do fail in service for a variety of reasons. In most cases, except for an increase in noise level and vibration, total gear failure is often the first and only indication of a problem. Many modes of gear...

  12. Can a 5 Week Strength Training Program Produce Range of Motion Adaptations in Amateur Female Tennis Players?

    Directory of Open Access Journals (Sweden)

    Andrew L. SHIM

    2015-12-01

    Full Text Available Objective: The purpose of this study was to assess range of motion adaptations in amateur tennis players based on the effects of a five week strength training program on the dominant and non-dominant arm. Subjects: An experimental and control group of six collegiate women tennis players (Div II and NAIA participated. After initial assessment, six subjects participated in a five week, four times a week, pre-season strength training program consisting of five exercises: External Rotation 90°, Seated Row, Scaption, Chest Press, and External Shoulder Rotation (Rubber tubing. Results: Data analysis through a paired t-test showed that there were no significant changes in ROM in the experimental group when compared to the control group. In conclusion, a strength training program is highly recommended for female overhead athletes combined with a proper flexibility regimen to promote best practice.

  13. Negative stiffness in gear contact

    Directory of Open Access Journals (Sweden)

    Půst L.

    2015-12-01

    Full Text Available The tooth contact stiffness is very often included in dynamic mathematical models of gear drives. It is an important value for calculation of torsion eigenfrequencies as well as the dynamic properties of the whole transmission systems. Planetary gear drives have several advantages over simple parallel axis gears, especially due to theirs compact design and great torque-to-weight ratio caused by multiple parallel paths. However, the dimensional or mounting errors can cause that some planets have the tendency to take more load than the others. One of the ways how to improve load sharing is the application of flexible planetary pins or by using a free central wheel. However in such cases, the wheels motion is defined in one rotation coordinate and two translation coordinates — tangential and radial. The reaction force at radial change of axis distance is usually neglected. The focus of this contribution is to derive the stiffness of this radial connection and to analyse the influence of radial stiffness on planetary gear dynamics.

  14. GEAR UP Aspirations Project Evaluation

    Science.gov (United States)

    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…

  15. Explosive Ordnance Disposal Proficiency Range and Multi-Purpose Contingency Training Area

    Science.gov (United States)

    2007-04-01

    etiquette , communications, treatment of nuclear, biological, chemical casualties and integrated base defense. Field training and night operation exercises... Asian alone 27,437 4% 30,390 4% NA - 393,957 5% Native Hawaiian/Pacific Islander alone 485 ə% 380 ə% NA - 3,900 ə% Other (alone and two or...visitors to Andrews AFB lodging and dining opportunities. Approximately 9,500 Camp Spring residents, 68% of the population, are employed in the

  16. Military Training: DOD Met Annual Reporting Requirements in Its 2016 Sustainable Ranges Report

    Science.gov (United States)

    2016-06-01

    from March 2016 to June 2016 in accordance with generally accepted government auditing standards . Those standards require that we plan and perform... internal , DOD factors and influences that constrain or have the potential to inhibit the full access or operational use of the live training and test...which the report met mandated statutory requirements and whether DOD faced challenges in preparing its report. We conducted this performance audit

  17. Vibroacoustic testing of gear transmissions for hoist drives

    Energy Technology Data Exchange (ETDEWEB)

    Antoniak, J.; Spalek, J. (Politechnika Slaska, Gliwice (Poland). Instytut Mechanizacji Gornictwa)

    1990-01-01

    The drive system of a hoist used in the Knurow black coal mine in Poland was investigated using vibroacoustic testing. The system consisted of 2 electric motors each with a power of 1,300 kW (600 r.p.m.) and the GCD-17 gear transmission. Vibrations and acoustic emission generated by individual elements of the mechanical transmission (roller bearings, gear wheels etc.) are evaluated. Design and operation of a measuring system, site selection of measuring points, frequency range of vibrations generated by the bearings or gears are analyzed. Examples of vibration spectra are evaluated. Recommendations for use of vibroacoustic testing in diagnostics of heavy-duty mining equipment are made. 3 refs.

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

    Directory of Open Access Journals (Sweden)

    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.

  19. Expeditionary Readiness Course Expansion Final Supplemental Environmental Assessment, Nevada Test and Training Range

    Science.gov (United States)

    2010-09-01

    constituting special-status taxa is relatively low (10 percent of flora). Cheatgrass, red brome , halogeton, and Russian thistle are invasive species that...NOXIOUS WEEDS AND INVASIVE PLANT SPECIES Cheatgrass (Bromus tectorum), red brome (Bromus madritensis var. rubens), halogeton (Halogeton glomeratus), and...found throughout the North Range. Red brome is mostly restricted to valley bottoms and alluvial fans in the South Range. Both of these grasses are

  20. 33 CFR 334.830 - Lake Michigan; small-arms range adjacent to U.S. Naval Training Center, Great Lakes, Ill.

    Science.gov (United States)

    2010-07-01

    ... adjacent to U.S. Naval Training Center, Great Lakes, Ill. 334.830 Section 334.830 Navigation and Navigable... REGULATIONS § 334.830 Lake Michigan; small-arms range adjacent to U.S. Naval Training Center, Great Lakes, Ill... section shall be enforced by the Commander, U.S. Naval Training Center, Great Lakes, Illinois, and such...

  1. Spectrum Management Guidelines for National and Service Test and Training Ranges

    Science.gov (United States)

    2017-07-12

    C-1 C.3 UAV/ Drone and Situational Awareness Data Link (PLRS/EPLRS/A-EPLRS, 420 – 450 MHz... GPS Global Positioning System ISM Installation Spectrum Manager JTIDS Joint Tactical Information Distribution System KMR Kwajalein Missile Range...Positioning System ( GPS ).” CJCSM 3212.03A. 8 November 2013. May be superseded by update. Available to users with appropriate credentials at

  2. Modeling and Validation of a Navy A6-Intruder Actively Controlled Landing Gear System

    Science.gov (United States)

    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 by using actively controlled landing gear. 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 are used to validate the model. The control design is described and closed-loop test and analysis comparisons are presented.

  3. Design of Gear Churning Power Loss Measurement Device

    OpenAIRE

    Wang Bin; Zhou Ya Jie; Wang Ping

    2017-01-01

    To explore the impacts of gear churning power losses, a research was conducted to achieve the internal causes of power losses of churning gear by designing a gear churning power losses measurement device. The gear churning power losses could be influenced by different gear modules, the number of teeth and the axial position of gear. Finally, the impacts of gear churning power losses were discussed by comparing experimental data and theoretical data.

  4. Investigation on wear characteristic of biopolymer gear

    Science.gov (United States)

    Ghazali, Wafiuddin Bin Md; Daing Idris, Daing Mohamad Nafiz Bin; Sofian, Azizul Helmi Bin; Basrawi, Mohamad Firdaus bin; Khalil Ibrahim, Thamir

    2017-10-01

    Polymer is widely used in many mechanical components such as gear. With the world going to a more green and sustainable environment, polymers which are bio based are being recognized as a replacement for conventional polymers based on fossil fuel. The use of biopolymer in mechanical components especially gear have not been fully explored yet. This research focuses on biopolymer for spur gear and whether the conventional method to investigate wear characteristic is applicable. The spur gears are produced by injection moulding and tested on several speeds using a custom test equipment. The wear formation such as tooth fracture, tooth deformation, debris and weight loss was observed on the biopolymer spur gear. It was noted that the biopolymer gear wear mechanism was similar with other type of polymer spur gears. It also undergoes stages of wear which are; running in, linear and rapid. It can be said that the wear mechanism of biopolymer spur gear is comparable to fossil fuel based polymer spur gear, thus it can be considered to replace polymer gears in suitable applications.

  5. ADAPTIVE DEFLECTION OF WING NOSE FLAP OF COMBAT TRAINING AIRCRAFT AND ITS IMPACT ON FLIGHT RANGE AND DURATION

    Directory of Open Access Journals (Sweden)

    M. V. Kondalov

    2014-01-01

    Full Text Available In this article presented the main result of numerical investigation of ability to improve the aerodynamic perfection of modern combat training aircraft. To determine the aerodynamic characteristic was used the discrete vortex method with closed vortex frames. In the work was presented the algorithm of a deflection of mechanization of a wing for increase of aerodynamic quality of the aircraft. The calculation of flight range and duration was at incremental extension and at realization of adaptive deflection of nose flap for Mach number M < 0.6.

  6. Dynamic investigation of a locomotive with effect of gear transmissions under tractive conditions

    Science.gov (United States)

    Chen, Zaigang; Zhai, Wanming; Wang, Kaiyun

    2017-11-01

    Locomotive is used to drag trailers to move or supply the braking forces to slow the running speed of a train. The electromagnetic torque of the motor is always transmitted by the gear transmission system to the wheelset for generation of the tractive or braking forces at the wheel-rail contact interface. Consequently, gear transmission system is significant for power delivery of a locomotive. This paper develops a comprehensive locomotive-track vertical-longitudinal coupled dynamics model with dynamic effect of gear transmissions. This dynamics model enables considering the coupling interactions between the gear transmission motion, the vertical and the longitudinal motions of the vehicle, and the vertical vibration of the track structure. In this study, some complicated dynamic excitations, such as the gear time-varying mesh stiffness, nonlinear gear tooth backlash, the nonlinear wheel-rail normal contact force and creep force, and the rail vertical geometrical irregularity, are considered. Then, the dynamic responses of the locomotive under the tractive conditions are demonstrated by numerical simulations based on the established dynamics model and by experimental test. The developed dynamics model is validated by the good agreement between the experimental and the theoretical results. The calculated results reveal that the gear transmission system has strong dynamic interactions with the wheel-rail contact interface including both the vertical and the longitudinal motions, and it has negligible effect on the vibrations of the bogie frame and carbody.

  7. Group-Effort Applied Research (GEAR): Expanding Opportunities for Undergraduate Research Through Original, Class-Based Research Projects

    Science.gov (United States)

    Moore, Sean D.; Teter, Ken

    2014-01-01

    Undergraduate research clearly enriches the educational development of participating students, but these experiences are limited by the inherent inefficiency of the standard one student - one mentor model for undergraduate research. Group-Effort Applied Research (GEAR) was developed as a strategy to provide substantial numbers of undergraduates with meaningful research experiences. The GEAR curriculum delivers concept-driven lecture material and provides hands-on training in the context of an active research project from the instructor's lab. Because GEAR is structured as a class, participating students benefit from intensive, supervised research training that involves a built-in network of peer support and abundant contact with faculty mentors. The class format also ensures a relatively standardized and consistent research experience. Furthermore, meaningful progress toward a research objective can be achieved more readily with GEAR than with the traditional one student - one mentor model of undergraduate research because sporadic mistakes by individuals in the class are overshadowed by the successes of the group as a whole. Three separate GEAR classes involving three distinct research projects have been offered to date. In this paper, we provide an overview of the GEAR format and review some of the recurring themes for GEAR instruction. We propose GEAR can serve as a template to expand student opportunities for life science research without sacrificing the quality of the mentored research experience. PMID:24898007

  8. 29 CFR 1919.19 - Gear requiring welding.

    Science.gov (United States)

    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 heat...

  9. A Circularly Arranged Sextuple Triptycene Gear Molecule.

    Science.gov (United States)

    Ube, Hitoshi; Yamada, Ryo; Ishida, Jun-Ichi; Sato, Hiroyasu; Shiro, Motoo; Shionoya, Mitsuhiko

    2017-11-22

    Herein we report the synthesis of a circularly arranged sextuple triptycene gear molecule, hexakis(10-dodecyloxy-9-triptycyl)ethynylbenzene, via the trimerization of the corresponding triyne with a cobalt catalyst. The six triptycene gears are closely engaged with each other as confirmed by single crystal X-ray structure analysis, and their motion in solution was established by NMR spectroscopy. Notably, when one bulky RuCp* complex was attached to one triptycene gear, the whole movement of the six gears was highly restricted via their mechanical engagement. Development of such a multigear molecule would provide a structural basis for molecular motion transmission systems with a switching function.

  10. Hypoid Gear Tooth Bearing Pattern Analysis : 1st Report, The Gear Dimensions for Tooth Bearing Development

    OpenAIRE

    高橋, 幸一; 伊藤, 紀男; 呉, 為民; 吉野, 雅禎

    1990-01-01

    Tooth bearing patterns for hypoid gears cannot be described by conventional theory. In gear manufacturing factories, tooth bearing development is still required in order to obtain good tooth bearing patterns. This paper presents a new method for the development of hypoid tooth bearing patterns which differs from the conventional and experimental gear cutting methods. This report makes it possible to obtain accurate hypoid gear dimensions which consist of the mating pressure angles, spiral ang...

  11. Parametric Design on Internal Gear of Cycloid Gear Pump with NX10.0

    Science.gov (United States)

    Zhang, Enguang; Chen, Min; Deng, Baoqing

    2017-10-01

    The parametric equation of the theoretical contour curve of cycloid gear was established in this paper. Using the NX10.0 software, parametric design of cycloidal gear profile curve was carried out, and the radius of curvature with the contour curve of cycloid gear was analyzed. The consistency between the simulation results and the theoretical design results was verified by assembly analysis, and the parametric drive of the cycloidal gear was verified simultaneously.

  12. Expression in grasses of multiple transgenes for degradation of munitions compounds on live-fire training ranges.

    Science.gov (United States)

    Zhang, Long; Routsong, Ryan; Nguyen, Quyen; Rylott, Elizabeth L; Bruce, Neil C; Strand, Stuart E

    2017-05-01

    The deposition of toxic munitions compounds, such as hexahydro-1, 3, 5-trinitro-1, 3, 5-triazine (RDX), on soils around targets in live-fire training ranges is an important source of groundwater contamination. Plants take up RDX but do not significantly degrade it. Reported here is the transformation of two perennial grass species, switchgrass (Panicum virgatum) and creeping bentgrass (Agrostis stolonifera), with the genes for degradation of RDX. These species possess a number of agronomic traits making them well equipped for the uptake and removal of RDX from root zone leachates. Transformation vectors were constructed with xplA and xplB, which confer the ability to degrade RDX, and nfsI, which encodes a nitroreductase for the detoxification of the co-contaminating explosive 2, 4, 6-trinitrotoluene (TNT). The vectors were transformed into the grass species using Agrobacterium tumefaciens infection. All transformed grass lines showing high transgene expression levels removed significantly more RDX from hydroponic solutions and retained significantly less RDX in their leaf tissues than wild-type plants. Soil columns planted with the best-performing switchgrass line were able to prevent leaching of RDX through a 0.5-m root zone. These plants represent a promising plant biotechnology to sustainably remove RDX from training range soil, thus preventing contamination of groundwater. © 2016 The Authors. Plant Biotechnology Journal published by Society for Experimental Biology and The Association of Applied Biologists and John Wiley & Sons Ltd.

  13. Load Sharing Behavior of Star Gearing Reducer for Geared Turbofan Engine

    Science.gov (United States)

    Mo, Shuai; Zhang, Yidu; Wu, Qiong; Wang, Feiming; Matsumura, Shigeki; Houjoh, Haruo

    2017-07-01

    Load sharing behavior is very important for power-split gearing system, star gearing reducer as a new type and special transmission system can be used in many industry fields. However, there is few literature regarding the key multiple-split load sharing issue in main gearbox used in new type geared turbofan engine. Further mechanism analysis are made on load sharing behavior among star gears of star gearing reducer for geared turbofan engine. Comprehensive meshing error analysis are conducted on eccentricity error, gear thickness error, base pitch error, assembly error, and bearing error of star gearing reducer respectively. Floating meshing error resulting from meshing clearance variation caused by the simultaneous floating of sun gear and annular gear are taken into account. A refined mathematical model for load sharing coefficient calculation is established in consideration of different meshing stiffness and supporting stiffness for components. The regular curves of load sharing coefficient under the influence of interactions, single action and single variation of various component errors are obtained. The accurate sensitivity of load sharing coefficient toward different errors is mastered. The load sharing coefficient of star gearing reducer is 1.033 and the maximum meshing force in gear tooth is about 3010 N. This paper provides scientific theory evidences for optimal parameter design and proper tolerance distribution in advanced development and manufacturing process, so as to achieve optimal effects in economy and technology.

  14. Impact of specific training and competition on myocardial structure and function in different age ranges of male handball players.

    Science.gov (United States)

    Agrebi, Brahim; Tkatchuk, Vladimir; Hlila, Nawel; Mouelhi, Emna; Belhani, Ali

    2015-01-01

    Handball activity involves cardiac changes and demands a mixture of both eccentric and concentric remodeling within the heart. This study seeks to explore heart performance and cardiac remodeling likely to define cardiac parameters which influence specific performance in male handball players across different age ranges. Forty three players, with a regular training and competitive background in handball separated into three groups aged on average 11.78 ± 0.41 for youth players aka "schools", "elite juniors" 15.99 ± 0.81 and "elite adults" 24.46 ± 2.63 years, underwent echocardiography and ECG examinations. Incremental ergocycle and specific field (SFT) tests have also been conducted. With age and regular training and competition, myocardial remodeling in different age ranges exhibit significant differences in dilatation's parameters between "schools" and "juniors" players, such as the end-diastolic diameter (LVEDD) and the end-systolic diameter of the left ventricle (LVESD), the root of aorta (Ao) and left atrial (LA), while significant increase is observed between "juniors" and "adults" players in the interventricular septum (IVS), the posterior wall thicknesses (PWT) and LV mass index. ECG changes are also noted but NS differences were observed in studied parameters. For incremental maximal test, players demonstrate a significant increase in duration and total work between "schools" and "juniors" and, in total work only, between "juniors" and "seniors". The SFT shows improvement in performance which ranged between 26.17 ± 1.83 sec to 31.23 ± 2.34 sec respectively from "seniors" to "schools". The cross-sectional approach used to compare groups with prior hypothesis that there would be differences in exercise performance and cardiac parameters depending on duration of prior handball practice, leads to point out the early cardiac remodeling within the heart as adaptive change. Prevalence of cardiac chamber dilation with less hypertrophy remodeling was found

  15. A fabrication process for electrostatic microactuators with integrated gear linkages

    NARCIS (Netherlands)

    Legtenberg, R.; Legtenberg, Rob; Berenschot, Johan W.; Elwenspoek, Michael Curt; Fluitman, J.H.J.

    A surface micromachining process is presented which has been used to fabricate electrostatic microactuators. These microactuators are interconnected with each other and linked to other movable microstructures by integrated gear linkages. The gear linkages consist of rotational and linear gear

  16. 50 CFR 654.22 - Gear restrictions.

    Science.gov (United States)

    2010-10-01

    ... 50 Wildlife and Fisheries 8 2010-10-01 2010-10-01 false Gear restrictions. 654.22 Section 654.22..., DEPARTMENT OF COMMERCE STONE CRAB FISHERY OF THE GULF OF MEXICO Management Measures § 654.22 Gear... be located on the top horizontal section of the trap. If the throat is longer in one dimension, the...

  17. 50 CFR 665.246 - Gear identification.

    Science.gov (United States)

    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 traps...

  18. 50 CFR 665.428 - Gear identification.

    Science.gov (United States)

    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 board...

  19. 50 CFR 665.128 - Gear identification.

    Science.gov (United States)

    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 board...

  20. 50 CFR 665.804 - Gear identification.

    Science.gov (United States)

    2010-10-01

    ... 50 Wildlife and Fisheries 9 2010-10-01 2010-10-01 false Gear identification. 665.804 Section 665.804 Wildlife and Fisheries FISHERY CONSERVATION AND MANAGEMENT, NATIONAL OCEANIC AND ATMOSPHERIC... Fisheries § 665.804 Gear identification. (a) Identification. The operator of each permitted vessel in the...

  1. 50 CFR 665.228 - Gear identification.

    Science.gov (United States)

    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 the...

  2. 50 CFR 665.628 - Gear identification.

    Science.gov (United States)

    2010-10-01

    ... 50 Wildlife and Fisheries 9 2010-10-01 2010-10-01 false Gear identification. 665.628 Section 665.628 Wildlife and Fisheries FISHERY CONSERVATION AND MANAGEMENT, NATIONAL OCEANIC AND ATMOSPHERIC... Fisheries § 665.628 Gear identification. (a) The vessel number must be affixed to all fish and crab traps on...

  3. Erratum: Professor J. H. S. Gear

    African Journals Online (AJOL)

    s short of their. Lesley, a nd their amily a proper Wake on 15 November 1994. Erratum: Professor J. H. S. Gear. The name of Professor B. D. Schoub, Director of the. National Institute for Virology, was inadvertently omitted as the author of the obituary of Professor J. H. S. Gear published in the September 1994 SAMJ. Books.

  4. Post-Closure Strategy for Use-Restricted Sites on the Nevada National Security Site, Nevada Test and Training Range, and Tonopah Test Range, Nevada

    Energy Technology Data Exchange (ETDEWEB)

    Silvas, A. J. [National Security Technologies, LLC. (NSTec), Mercury, NV (United States)

    2014-03-26

    The purpose of this Post-Closure Strategy is to provide a consistent methodology for continual evaluation of post-closure requirements for use-restricted areas on the Nevada National Security Site (NNSS), Nevada Test and Training Range (NTTR), and Tonopah Test Range (TTR) to consolidate, modify, or streamline the program. In addition, this document stipulates the creation of a single consolidated Post-Closure Plan that will detail the current post-closure requirements for all active use restrictions (URs) and outlines its implementation and subsequent revision. This strategy will ensure effective management and control of the post-closure sites. There are currently over 200 URs located on the NNSS, NTTR, and TTR. Post-closure requirements were initially established in the Closure Report for each site. In some cases, changes to the post-closure requirements have been implemented through addenda, errata sheets, records of technical change, or letters. Post-closure requirements have been collected from these multiple sources and consolidated into several formats, such as summaries and databases. This structure increases the possibility of inconsistencies and uncertainty. As more URs are established and the post-closure program is expanded, the need for a comprehensive approach for managing the program will increase. Not only should the current requirements be obtainable from a single source that supersedes all previous requirements, but the strategy for modifying the requirements should be standardized. This will enable more effective management of the program into the future. This strategy document and the subsequent comprehensive plan are to be implemented under the assumption that the NNSS and outlying sites will be under the purview of the U.S. Department of Energy, National Nuclear Security Administration for the foreseeable future. This strategy was also developed assuming that regulatory control of the sites remains static. The comprehensive plan is not

  5. Magnetorheological fluids and applications to adaptive landing gear for a lightweight helicopter

    Science.gov (United States)

    Ahure-Powell, Louise A.

    During hard landing or crash events of a helicopter there are impact loads that can be injurious to crew and other occupants as well as damaging to the helicopter structure. Landing gear systems are the first in line to protect crew and passengers from detrimental crash loads. The main focus of this research is to improve landing gear systems of a lightweight helicopter. Magnetorheological fluids (MRFs) provide potential solutions to several engineering challenges in a broad range of applications. One application that has been considered recently is the use of magnetorheological (MR) dampers in helicopter landing gear systems. In such application, the adaptive landing gear systems have to continuously adjust their stroking load in response to various operating conditions. In order to support this rotorcraft application, there is a necessity to validate that MRFs are qualified for landing gear applications. First, MRF composites, synthesized utilizing three hydraulic oils certified for use in landing gear systems, two average diameters of spherical magnetic particles, and a lecithin surfactant, are formulated to investigate their performance for potential use in a helicopter landing gear. The magnetorheology of these MR fluids is characterized through a range of tests, including (a) magnetorheology (yield stress and viscosity) as a function of magnetic field, (b) sedimentation analysis using an inductance-based sensor, (c) cycling of a small-scale MR damper undergoing sinusoidal excitations (at 2.5 and 5 Hz), and (d) impact testing of an MR damper for a range of magnetic field strengths and velocities using a free-flight drop tower facility. The performance of these MR fluids was analyzed, and their behavior was compared to standard commercial MR fluids. Based on this range of tests used to characterize the MR fluids synthesized, it was shown that it is feasible to utilize certified landing gear hydraulic oils as the carrier fluids to make suitable MR fluids

  6. FATIGUE PROPERTIES OF SPRING REINFORCES POLYMER GEARS

    Directory of Open Access Journals (Sweden)

    Hilal CAN

    2005-03-01

    Full Text Available Failure of gears, occur surface pressure stress and fracture at base of teeth. For steel gears, it is known that process of carburizing increases fatigue strength. Internal stress on the surface increases of fracture fatigue strength. In this study fatigue properties of polypropylene gear reinforced with 1.2 mm wire diameter metallic springs was investigated. Extension springs were used as reinforcement element and placed into the mould and stretched before injection of polypropylene material into the mould. After injection of polypropylene, stretched springs were loosened in order to obtain pre-stressing. Fatigue tests were performed on the produced gear. Reinforcement increased the strength of gears. At result of experiments, pre-stressing increase in service life 12 times more than that of specimens without reinforcement.

  7. Gear Crack Level Classification Based on EMD and EDT

    Directory of Open Access Journals (Sweden)

    Haiping Li

    2015-01-01

    Full Text Available Gears are the most essential parts in rotating machinery. Crack fault is one of damage modes most frequently occurring in gears. So, this paper deals with the problem of different crack levels classification. The proposed method is mainly based on empirical mode decomposition (EMD and Euclidean distance technique (EDT. First, vibration signal acquired by accelerometer is processed by EMD and intrinsic mode functions (IMFs are obtained. Then, a correlation coefficient based method is proposed to select the sensitive IMFs which contain main gear fault information. And energy of these IMFs is chosen as the fault feature by comparing with kurtosis and skewness. Finally, Euclidean distances between test sample and four classes trained samples are calculated, and on this basis, fault level classification of the test sample can be made. The proposed approach is tested and validated through a gearbox experiment, in which four crack levels and three kinds of loads are utilized. The results show that the proposed method has high accuracy rates in classifying different crack levels and may be adaptive to different conditions.

  8. Fishing-gear restrictions and biomass gains for coral reef fishes in marine protected areas.

    Science.gov (United States)

    Campbell, Stuart J; Edgar, Graham J; Stuart-Smith, Rick D; Soler, German; Bates, Amanda E

    2017-08-04

    Strong empirical evidence supports recovery of reef fish populations with fishery closures. In countries where full exclusion of people from fishing may be perceived as inequitable, fishing gear restrictions on non-selective and destructive gears may offer socially relevant management alternatives to build recovery of fish biomass. Even so, very few studies have statistically compared the responses of tropical reef fisheries to alternative management strategies. Here we test for the effects of fishery closures and fishing gear restrictions on tropical reef fish biomass, at the community and family level, at 1,396 underwater surveys conducted at 617 unique sites across a spatial hierarchy within 22 global marine ecoregions representing five realms. We compare total biomass across local fish assemblages, and among 20 reef fish families inside marine protected areas (MPAs) with different fishing restrictions: no-take, hook and line fishing only, several fishing gears allowed, to sites open to all fishing gears. We include a further category representing remote sites where fishing pressure is low. As expected, full fishery closures, often referred to as 'no-take' zones, most benefit community and family level fish biomass in comparison with restrictions on fishing gears and openly fished sites. We further find that although biomass responses to fishery closures are highly variable across families, some fishery targets (e.g., Carcharhinidae, and Lutjanidae) respond positively to multiple restrictions on fishing gears (i.e., where gears other than hook and line fishing are not permitted). Remoteness also imparts a positive influence on the response of community level fish biomass and many fish families. Our findings provide strong support for the role of fishing restrictions in building recovery of fish biomass, and indicate important interactions among fishing gear types on removal of fish biomass among a range of reef fish families. This article is protected by

  9. Treadmill training with an incline reduces ankle joint stiffness and improves active range of movement during gait in adults with cerebral palsy

    DEFF Research Database (Denmark)

    Lorentzen, Jakob; Kirk, Henrik; Fernandez-Lago, Helena

    2017-01-01

    PURPOSE: We investigated if 30 min of daily treadmill training with an incline for 6 weeks would reduce ankle joint stiffness and improve active range of movement in adults with cerebral palsy (CP). METHODS: The study was designed as a randomized controlled clinical trial including 32 adults...... with CP (GMFCS 1-3) aged 38.1 SD 12 years. The training group (n = 16) performed uphill treadmill training at home daily for 30 min for 6 weeks in addition to their usual activities. Passive and reflex mediated stiffness and range of motion (ROM) of the ankle joint, kinematic and functional measures...

  10. Impact of specific training and competition on myocardial structure and function in different age ranges of male handball players.

    Directory of Open Access Journals (Sweden)

    Brahim Agrebi

    Full Text Available Handball activity involves cardiac changes and demands a mixture of both eccentric and concentric remodeling within the heart. This study seeks to explore heart performance and cardiac remodeling likely to define cardiac parameters which influence specific performance in male handball players across different age ranges. Forty three players, with a regular training and competitive background in handball separated into three groups aged on average 11.78 ± 0.41 for youth players aka "schools", "elite juniors" 15.99 ± 0.81 and "elite adults" 24.46 ± 2.63 years, underwent echocardiography and ECG examinations. Incremental ergocycle and specific field (SFT tests have also been conducted. With age and regular training and competition, myocardial remodeling in different age ranges exhibit significant differences in dilatation's parameters between "schools" and "juniors" players, such as the end-diastolic diameter (LVEDD and the end-systolic diameter of the left ventricle (LVESD, the root of aorta (Ao and left atrial (LA, while significant increase is observed between "juniors" and "adults" players in the interventricular septum (IVS, the posterior wall thicknesses (PWT and LV mass index. ECG changes are also noted but NS differences were observed in studied parameters. For incremental maximal test, players demonstrate a significant increase in duration and total work between "schools" and "juniors" and, in total work only, between "juniors" and "seniors". The SFT shows improvement in performance which ranged between 26.17 ± 1.83 sec to 31.23 ± 2.34 sec respectively from "seniors" to "schools". The cross-sectional approach used to compare groups with prior hypothesis that there would be differences in exercise performance and cardiac parameters depending on duration of prior handball practice, leads to point out the early cardiac remodeling within the heart as adaptive change. Prevalence of cardiac chamber dilation with less hypertrophy remodeling

  11. Impact of specific training and competition on myocardial structure and function in different age ranges of male handball players

    Science.gov (United States)

    Agrebi, Brahim; Tkatchuk, Vladimir; Hlila, Nawel; Mouelhi, Emna; Belhani, Ali

    2015-01-01

    Handball activity involves cardiac changes and demands a mixture of both eccentric and concentric remodeling within the heart. This study seeks to explore heart performance and cardiac remodeling likely to define cardiac parameters which influence specific performance in male handball players across different age ranges. Forty three players, with a regular training and competitive background in handball separated into three groups aged on average 11.78±0.41 for youth players aka “schools”, “elite juniors” 15.99±0.81 and “elite adults” 24.46±2.63 years, underwent echocardiography and ECG examinations. Incremental ergocycle and specific field (SFT) tests have also been conducted. With age and regular training and competition, myocardial remodeling in different age ranges exhibit significant differences in dilatation’s parameters between “schools” and “juniors” players, such as the end-diastolic diameter (LVEDD) and the end-systolic diameter of the left ventricle (LVESD), the root of aorta (Ao) and left atrial (LA), while significant increase is observed between “juniors” and “adults” players in the interventricular septum (IVS), the posterior wall thicknesses (PWT) and LV mass index. ECG changes are also noted but NS differences were observed in studied parameters. For incremental maximal test, players demonstrate a significant increase in duration and total work between “schools” and “juniors” and, in total work only, between “juniors” and “seniors”. The SFT shows improvement in performance which ranged between 26.17±1.83 sec to 31.23±2.34 sec respectively from “seniors” to “schools”. The cross-sectional approach used to compare groups with prior hypothesis that there would be differences in exercise performance and cardiac parameters depending on duration of prior handball practice, leads to point out the early cardiac remodeling within the heart as adaptive change. Prevalence of cardiac chamber dilation

  12. Effects of two proprioceptive training programs on ankle range of motion, pain, functional and balance performance in individuals with ankle sprain.

    Science.gov (United States)

    Lazarou, Lazaros; Kofotolis, Nikolaos; Pafis, Georgios; Kellis, Eleftherios

    2017-09-08

    Following ankle sprain, residual symptoms are often apparent, and proprioceptive training is a treatment approach. Evidence, however, is limited and the optimal program has to be identified. To investigate the effects of two post-acute supervised proprioceptive training programs in individuals with ankle sprain. Participants were recruited from a physiotherapy center for ankle sprain rehabilitation. In a pre-post treatment, blinded-assessor design, 22 individuals were randomly allocated to a balance or a proprioceptive neuromuscular facilitation (PNF) group. Both groups received 10 rehabilitation sessions, within a six-week period. Dorsiflexion range of motion (ROM), pain, functional and balance performance were assessed at baseline, at the end of training and eight weeks after training. Follow-up data were provided for 20 individuals. Eight weeks after training, statistically significant (pfunctional performance measures for both balance and PNF groups. Eight weeks after training, significant (pfunctional performance in individuals with sprain. Balance programs are also recommended for pain relief.

  13. How automatic is manual gear shifting?

    Science.gov (United States)

    Shinar, D; Meir, M; Ben-Shoham, I

    1998-12-01

    Manual gear shifting is often used as an example of an automated (vs. controlled) process in driving. The present study provided an empirical evaluation of this assumption by evaluating sign detection and recall performance of novice and experienced drivers driving manual shift and automatic transmission cars in a downtown area requiring frequent gear shifting. The results showed that manual gear shifting significantly impaired sign detection performance of novice drivers using manual gears compared with novice drivers using an automatic transmission, whereas no such differences existed between the two transmission types for experienced drivers. The results clearly demonstrate that manual gear shifting is a complex psychomotor skill that is not easily (or quickly) automated and that until it becomes automated, it is an attention-demanding task that may impair other monitoring aspects of driving performance. Actual or potential applications of this research include a reevaluation of the learning process in driving and the need for phased instruction in driving from automatic gears to manual gears.

  14. Vehicle transmission gear 2009; Getriebe in Fahrzeugen 2009

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    2009-07-01

    with single dry clutch and electric torque support (G. Hellenbroich); (37) New solutions to increase cost-effectiveness of city bus drive lines with modern automatic powershift transmissions (P. Wunderlich); (38) Evaluation of the gearchanging comfort at commercial vehicles (W. Wessel); (39) New structure-optimised transmission systems for advanced commercial vehicles (R. Resch); (40) Depth of details of powertrain models for depocting driveability effects (F. Matthies); (41) A nonlinear transmission approach for dual mass flywheels (C. Benatzky); (42) Clattering and rattling is still a challenge for vehicle transmission developers (M. Dally); (43) Study on the effect of driving cycles on energy efficiency of electric vehicles (J. Fenzhu); (44) Modular modelling and simulation of hybrid power trains (G. Kelz); (45) The integration of electrical axle drives in hybrid vehicle and electric vehicles (H. Schaefer); (46) Energy balance of the optimized CVT hybrid driveline (B.-R. Hoehm); (47) Functional efficiency comparison between split- and parallel-hybrid using advanced energy flow analysis methods (P. Guttenberg); (48) Simulation of the fuel consumption benefits of various transmission arrangements and control strategies within a flywheel based mechanical hybrid system (W. Body); (49) Ideal test specifications for transmissions (T. Kassel); (50) The 'Hybrid Effect': Influence of hybridisation on the durability of automatic transmissions (T. Lavall); (51) Schaeffler lightweight differentials (R. Malik); (52) Integrated all wheel drive in the ZF eight-speed automatic gear (D. Baasch); (53) Optimized structures for amplifying torque vectoring systems (A. Sue); (54) The new sport differential in the Audi S4 (U. Pinschmidt).

  15. The hydrodynamic drag and the mobilisation of sediment into the water column of towed fishing gear components

    Science.gov (United States)

    O'Neill, F. G.; Summerbell, K. J.

    2016-12-01

    The hydrodynamic drag of towed fishing gears leads to direct impacts on the benthic environment, and can play a major role in the overall economic efficiency of the fishing operation and emissions of nitrogen oxides, sulphur oxides and greenhouse gases such as CO2. Here we investigate some of the underpinning processes which govern these issues and make direct hydrodynamic drag measurements and calculate the hydrodynamic drag coefficients for a range of well-defined gear components that, when fished, are in contact with the seabed. We measure the concentration and particle size distribution of the sediment mobilised into the water column in the wake of these gear elements, at a range of towing speeds, and demonstrate that as the hydrodynamic drag increases the amount of sediment mobilised also increases. We also vary the weight of the elements and show that this does not influence the amount of sediment put into the water column. These results provide a better understanding of the physical and mechanical processes that take place when a towed fishing gear interacts with the seabed. They will permit the development of more fuel efficient gears and gears of reduced benthic impact and will improve the empirical modelling of the sediment mobilised into the turbulent wake behind towed fishing gears which will lead to better assessments of the environmental and ecological impact of fishing gears.

  16. Engagement of Metal Debris into Gear Mesh

    Science.gov (United States)

    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.

  17. MODERNIZATION OF TRACKED VEHICLE RUNNING GEARS

    Directory of Open Access Journals (Sweden)

    V. A. Korobkin

    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.

  18. Fuel economy of multigrade gear lubricants

    Energy Technology Data Exchange (ETDEWEB)

    Bala, V. [Ethyl Petroleum Additives Inc., Richmond, VA (United States); Brandt, G. [Ethyl Mineraloel-Additives GmbH, Hamburg (Germany); Walters, D.K. [Ethyl Petroleum Additives Ltd., Bracknell (United Kingdom)

    2000-06-09

    The paper discusses the setup of a light duty axle efficiency test in evaluating gear lubricants for their fuel economy performance. Data collected with an internal reference oil highlight the repeatability of the test in different axles. Comparisons between single grade SAE 90 to multigrade gear lubricants were made under a variety of pinion torques and speeds to simulate highway and city driving conditions. A discussion of lubricant rheology and its importance to maintaining film strength for adequate bearing and gear lubrication for optimum torque efficiency and axle temperature is provided. (Author)

  19. DESIGN OF AN EFFICIENT GEAR DRIVEN BICYCLE

    OpenAIRE

    K. Rajasuthan*, G. Balaji, M. Palpandi

    2016-01-01

    In our project bicycle is driven with a series of spur gears which will increase the speed of bicycle and also the bicycles becomes more efficient than a conventional sprocket driven bicycle. Spur gears are used in series to transmit power from the pedal to the rear wheel of the bicycle. This bicycle enables us to put less effort for pedaling. For a very low input effort, we can get maximum output. Distance covered by this gear driven bicycle for few minutes of pedaling will also be 3-4 times...

  20. VARIABLE MESH STIFFNESS OF SPUR GEAR TEETH USING ...

    African Journals Online (AJOL)

    primary source of parametric vibration excitation in geared systems, by virtue of large magnitude change in stiffness that occurs during gear engagement. A gear mesh kinematic simulation. WIll be developeJ 1(1 simulate the meshing actIOn 01 two spur gears,. Recently, greatcr elliphasis has been played on the creation of ...

  1. Development of a high-performance magnetic gear

    DEFF Research Database (Denmark)

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

    2005-01-01

    This paper presents calculation and measurement results of a highperformance permanent-magnetic gear. The analyzed permanent-magnetic gear has a gear ratio of 5.5 and is able to deliver 27 N.m. The analysis has shown that special attention needs to be paid to the system where the gear is to be in...

  2. 46 CFR 108.641 - Instructions for changing steering gear.

    Science.gov (United States)

    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 steering...

  3. 49 CFR 230.77 - Foundation brake gear.

    Science.gov (United States)

    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 be...

  4. 14 CFR 25.1515 - Landing gear speeds.

    Science.gov (United States)

    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, as...

  5. 46 CFR 58.25-20 - Piping for steering gear.

    Science.gov (United States)

    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 be...

  6. 29 CFR 1919.31 - Proof tests-loose gear.

    Science.gov (United States)

    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 (whether...

  7. Group 13, 1990 Astronaut Class candidate Sherlock examines T-38 landing gear

    Science.gov (United States)

    1990-01-01

    Astronaut candidate (ASCAN) Nancy J. Sherlock examines T-38A landing gear along with a NASA Staff Pilot during T-38A flight training at Ellington Field located near JSC. Sherlock, along with classmates from the Group 13 1990 Astronaut class, participated in the familiarization session prior to flying aboard the T-38A aircraft.

  8. Improving applied roughness measurement of involute helical gears

    Science.gov (United States)

    Koulin, G.; Zhang, J.; Frazer, R. C.; Wilson, S. J.; Shaw, B. A.

    2017-12-01

    With improving gear design and manufacturing technology, improvement in metrology is necessary to provide reliable feedback to the designer and manufacturer. A recommended gear roughness measurement method is applied to a micropitting contact fatigue test gear. The development of wear and micropitting is reliably characterised at the sub-micron roughness level. Changes to the features of the localised surface texture are revealed and are related to key gear meshing positions. The application of the recommended methodology is shown to provide informative feedback to the gear designer in reference to the fundamental gear coordinate system, which is used in gear performance simulations such as tooth contact analysis.

  9. Efficiency of nonstandard and high contact ratio involute spur gears

    Science.gov (United States)

    Anderson, N. E.; Loewenthal, S. H.

    1986-01-01

    A power loss prediction was extended to include involute spur gears of nonstandard proportions. The method is used to analyze the effects of modified addendum, tooth thickness, and gear center distance in addition to the parameters previously considered which included gear diameter, pitch, pressure angle, face width, oil viscosity, speed, and torque. Particular emphasis was placed on high contact ratio gearing (contact ratios greater than two). Despite their higher sliding velocities, high contact ratio gears are designed to levels of efficiency comparable to those of conventional gears while retaining their advantages through proper selection of gear geometry.

  10. Automatic gear sorting system based on monocular vision

    Directory of Open Access Journals (Sweden)

    Wenqi Wu

    2015-11-01

    Full Text Available An automatic gear sorting system based on monocular vision is proposed in this paper. A CCD camera fixed on the top of the sorting system is used to obtain the images of the gears on the conveyor belt. The gears׳ features including number of holes, number of teeth and color are extracted, which is used to categorize the gears. Photoelectric sensors are used to locate the gears׳ position and produce the trigger signals for pneumatic cylinders. The automatic gear sorting is achieved by using pneumatic actuators to push different gears into their corresponding storage boxes. The experimental results verify the validity and reliability of the proposed method and system.

  11. Sea Turtle Human/Gear Interactions Data

    Data.gov (United States)

    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...

  12. Vibration Based Sun Gear Damage Detection

    Science.gov (United States)

    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.

  13. Deformation and stiffness of spur gear teeth and their influence on gear noise

    Directory of Open Access Journals (Sweden)

    Silvia MEDVECKÁ-BEŇOVÁ

    2015-12-01

    Full Text Available Gear teeth are deformed due to the load. The deformation of gear teeth is causing some negative as well as positive effects. A tooth has a complex shape and due to the complex shape of the teeth, a theoretical determination of the deformation is difficult. The existing experimental techniques are based on static deflection measurements gearing loaded of constant force or seismic measurement deviations at slow rotation. Recently, at ever faster evolving computer technology and the available literature, we can encounter modern numerical methods, such as finite element method (FEM, which can serve as methods for the determination of teeth of gearing. The article is devoted to the problems of gearing stiffness analysis. The problem is solved for spur gears. Deformation analysis solved by FEM is used for calculations of the gearing stiffness. There are many influences that cause vibrations in the gearbox and that have to be taken into account already in the phase of design, manufacture, installation and operation. Detailed analysis of gearboxes manufacturers have shown that improving of the gear accuracy cannot reduce the transmission unit noise to the desired level. Only fundamental changes to the shape of the tooth and changes in production technology can achieve stronger noise reduction of gear mechanism.

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

    Science.gov (United States)

    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.

  15. More Electric Landing Gear Actuation Study

    OpenAIRE

    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...

  16. Instrumentation and test gear circuits manual

    CERN Document Server

    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

  17. Structure design and motion simulation of the pin-cycloid gear planetary reducer with ring-plate-type

    Science.gov (United States)

    Duan, Hongjie; Li, Lijun; Tao, Junyi

    2017-06-01

    The pin-cycloid gear planetary reducer with ring-plate-type is a new type of reducers. It has high transmission ratio range and high efficiency. In this paper the working principle of pin-cycloid gear planetary reducer is discussed, and the structure of the reducer is designed. Especially for the complexity and the difficulty in modelling of the cycloid gear tooth profile, the parametric design module of cycloid gear is developed to solve the cycloid gear modelling problem through the second development of Solid Works. At last, the speed schemes of the input shaft and output shaft of the reducer are obtained by the motion simulation. Through the analysis of the simulation curves, the rationality of the structure design is proved, which provides a theoretical basis for the design and manufacture of the reducer.

  18. Hantaan virus surveillance targeting small mammals at nightmare range, a high elevation military training area, Gyeonggi Province, Republic of Korea.

    Directory of Open Access Journals (Sweden)

    Terry A Klein

    Full Text Available Rodent-borne disease surveillance was conducted at Nightmare Range (NM-R, near the demilitarized zone in northeast Gyeonggi Province, Republic of Korea, to identify hemorrhagic fever with renal syndrome (HFRS risks for a mountainous high-elevation (500 m military training site. Monthly surveys were conducted from January 2008-December 2009. A total of 1,720 small mammals were captured belonging to the Orders Rodentia [Families, Sciuridae (1 species and Muridae (7 species] and Soricomorpha [Family, Soricidae (1species]. Apodemus agrarius, the primary reservoir for Hantaan virus (HTNV, accounted for 89.9% (1,546 of all small mammals captured, followed by Myodes regulus (4.0%, Crocidura lasiura (3.9%, Micromys minutus (1.4%, Mus musculus (0.3%, Microtus fortis (0.2%, Apodemus peninsulae (0.2%, Tamias sibiricus (0.1%, and Rattus norvegicus (<0.1%. Three species were antibody-positive (Ab+ for hantaviruses: A. agrarius (8.2%, M. minutus (4.2%, and C. lasiura (1.5%. HTNV specific RNA was detected in 93/127 Ab+ A. agrarius, while Imjin virus specific RNA was detected in 1/1 Ab+ C. lasiura. Overall, hantavirus Ab+ rates for A. agrarius increased with weight (age and were significantly higher among males (10.9% than females (5.1% (P<0.0001. High A. agrarius gravid rates during the fall (August-September were associated with peak numbers of HFRS cases in Korea that followed high gravid rates. From 79 RT-PCR positive A. agrarius, 12 HTNV RNA samples were sequenced and compared phylogenetically based on a 320 nt sequence from the GC glycoprotein-encoding M segment. These results demonstrate that the HTNV isolates from NM-R are distinctly separated from HTNV isolated from the People's Republic of China. These studies provide for improved disease risk assessments that identify military activities, rodent HTNV rates, and other factors associated with the transmission of hantaviruses during field training exercises.

  19. Straddle Design Of Spiral Bevel And Hypoid Gears

    Science.gov (United States)

    Handschuh, Robert F.; Litvin, Faydor L.; Kuan, Chihping; Kieffer, Jonathan; Bossler, Robert

    1994-01-01

    Computer-assisted method of analysis of straddle designs for spiral bevel and hypoid gears helps prevent undercutting of gear shafts during cutting of gear teeth. Analytical method and computer program based on equations for surface traced out by motion of head cutter, equation for cylindrical surface of shaft, and equations expressing relationships among coordinate systems fixed to various components of gear-cutting machine tool and gear.

  20. Voice training and changing weight--are they reflected in speaking fundamental frequency, voice range, and pitch breaks of 13-year-old girls? A longitudinal study.

    Science.gov (United States)

    Willis, Elizabeth C; Kenny, Dianna T

    2011-09-01

    Assessment of the voice-change progress of 20 girls (12-13 years) over 1 year by observing changes in speaking fundamental frequency (SFo), voice range, and register pitch breaks in the context of weight, height, voice training, and self-perception. One-year longitudinal collective case study. Twenty girls were recorded at the beginning and end of a year; nine girls were recorded another three times. SFo, vocal range, and characteristics were analyzed and interactions between these data assessed against weight and height to indicate pubertal development, and to test the hypothesis that changes in weight, height, SFo, and pitch breaks were related. Effects of training and the girls' self-perception of their voice use were also assessed. Vocal characteristics changed as the girls passed through different weight ranges. During 47.5-52.4 kg (called band 2) and 52.4-57.5 kg (band 3), there was progressive contraction of vocal range and in some girls a slight rise in SFo between recording times 1 and 5. Both high- and low-pitch breaks were present in 45% of girls' voices. Girls in band 4 (pitch breaks in vocal-range areas that indicated the development of adult vocal registers. In this study, voice-trained girls were heavier, had higher SFo, used wider speech-range inflection, had a higher vocal range, and greater voice-use confidence; all girls lost confidence in their voice use over the year. In this longitudinal study of twenty 13-year-old girls, voice changes in SFo, vocal range, and pitch-break frequency were synchronous with certain weight ranges. Girls with training registered higher maximum phonational frequency and were more confident in their voice use than girls without training. Copyright © 2011 The Voice Foundation. Published by Mosby, Inc. All rights reserved.

  1. Failure of Harmonic Gears During Verification of a Two-Axis Gimbal for the Mars Reconnaissance Orbiter Spacecraft

    Science.gov (United States)

    Johnson, Michael R.; Gehling, Russ; Head, Ray

    2006-01-01

    The Mars Reconnaissance Orbiter (MRO) spacecraft has three two-axis gimbal assemblies that support and move the High Gain Antenna and two solar array wings. The gimbal assemblies are required to move almost continuously throughout the mission's seven-year lifetime, requiring a large number of output revolutions for each actuator in the gimbal assemblies. The actuator for each of the six axes consists of a two-phase brushless dc motor with a direct drive to the wave generator of a size-32 cup-type harmonic gear. During life testing of an actuator assembly, the harmonic gear teeth failed completely, leaving the size-32 harmonic gear with a maximum output torque capability less than 10% of its design capability. The investigation that followed the failure revealed limitations of the heritage material choices that were made for the harmonic gear components that had passed similar life requirements on several previous programs. Additionally, the methods used to increase the stiffness of a standard harmonic gear component set, while accepted practice for harmonic gears, is limited in its range. The stiffness of harmonic gear assemblies can be increased up to a maximum stiffness point that, if exceeded, compromises the reliability of the gear components for long life applications.

  2. Nonlinear modeling of adaptive magnetorheological landing gear dampers under impact conditions

    Science.gov (United States)

    Ahuré Powell, Louise A.; Choi, Young T.; Hu, Wei; Wereley, Norman M.

    2016-11-01

    Adaptive landing gear dampers that can continuously adjust their stroking load in response to various operating conditions have been investigated for improving the landing performance of a lightweight helicopter. In prior work, adaptive magnetorheological (MR) landing gear dampers that maintained a constant peak stroking force of 4000 lbf across sink rates ranging from 6 to 12 ft s‑1 were designed, fabricated and successfully tested. In this follow-on effort, it is desired to expand the high end of the sink rate range to hold the peak stroking load constant for sink rates ranging from 6 to 26 ft s‑1, thus extending the high end of the speed range from 12 (in the first study) to 26 ft s‑1. To achieve this increase, a spring-based relief valve MR landing gear damper was developed. In order to better understand the MR landing gear damper behavior, a modified nonlinear Bingham Plastic model was formulated, and it incorporates Darcy friction, viscous forces across the MR and relief valves to better account for the damper force behavior at higher speeds. In addition, gas pressure inside the MR damper piston is considered so the total damper force includes a gas force. The MR landing gear damper performance is characterized using drop tests, and the experiments are used to validate model predictions data at low and high nominal impact speeds up to 26 ft s‑1 (shaft velocity of 9.6 ft s‑1).

  3. 77 FR 6084 - Taking and Importing Marine Mammals; U.S. Navy Training in the Southern California Range Complex

    Science.gov (United States)

    2012-02-07

    ... 2008. There was a Major Training Exercise (MTE) the same day of the sighting, but it was 30-50 nautical... training event with MMOs, 24 sightings were made of about 599 marine mammals. The frequency of sightings... sightings during MTEs, there were 110 sightings within 1,000 yards that qualified as mitigation events...

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

    Science.gov (United States)

    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.

  5. Role of soil organic carbon and colloids in sorption and transport of TNT, RDX and HMX in training range soils.

    Science.gov (United States)

    Sharma, Prasesh; Mayes, Melanie A; Tang, Guoping

    2013-08-01

    Contamination of soils and groundwater by munitions compounds (MCs) is of significant concern at many U.S. Department of Defense sites. Soils were collected from operational training ranges in Maryland (APG), Massachusetts (MMR-B and MMR-E) and Washington (JBLM) and sorption and transport studies were conducted to investigate the effects of soil organic carbon (OC) and textural clay content on fate of dissolved MCs (TNT, RDX, HMX). Sorption experiments showed higher distribution coefficients [TNT:42-68 L kg(-1), RDX:6.9-8.7 L kg(-1) and HMX:2.6-3.1 L kg(-1)] in OC rich soils (JBLM, MMR-E) compared to clay rich soils (MMR-B and APG) [TNT:19-21 L kg(-1), RDX:2.5-3.4 L kg(-1), HMX:0.9-1.2 L kg(-1)]. In column experiments, breakthrough of MCs was faster in MMR-B and APG compared to MMR-E and JBLM soils. Among TNT, RDX and HMX, breakthrough was fastest for RDX followed by HMX and TNT for all columns. Defining the colloidal fraction as the difference between unfiltered samples and samples filtered with a 3 kDa filter, ~36%, ~15% and ~9% of TNT, RDX and HMX were found in the colloidal fraction in the solutions from sorption experiments, and around 20% of TNT in the effluent from the transport experiments. Results demonstrate that OC rich soils may enhance sorption and delay transport of TNT, RDX and HMX compared to clay-rich soils. Further, transport of TNT may be associated with soil colloid mobilization. Copyright © 2013 Elsevier Ltd. All rights reserved.

  6. Gear Tooth Root Stresses of a Very Heavily Loaded Gear Pair-Case Study: Orbiter Body Flap Actuator Pinion and Ring Gear

    Science.gov (United States)

    Krantz, Timothy L.; Handschuh, Robert F.

    2015-01-01

    The space shuttle orbiter's body flap actuator gearing was assessed as a case study of the stresses for very heavily loaded external-internal gear pairs (meshing pinion and ring gear). For many applications, using the high point of single tooth contact (HPSTC) to locate the position of the tooth force is adequate for assessing the maximum tooth root stress condition. But for aerospace gearing such an approach may be inadequate for assessing the stress condition while also simultaneously minimizing mass. In this work specialized contact analyses and finite element methods were used to study gear tooth stresses of body flap actuator gears. The analytical solutions considered the elastic deformations as an inherent part of the solutions. The ratio for the maximum tooth stresses using the HPSTC approach solutions relative to the contact analysis and finite element solutions were 1.40 for the ring gear and 1.28 for the pinion gear.

  7. PECULIARITIES OF RUNNING GEAR CONSTRUCTION OF ROLLING STOCK

    Directory of Open Access Journals (Sweden)

    S. V. Myamlin

    2017-06-01

    Full Text Available Purpose. To determine the dynamic qualities of the main locomotives that characterize safety traffic along straight and curved track sections in the entire range of operational speeds, it is necessary to perform a whole range of studies. One of the necessary conditions for a qualitative improvement of the traction rolling stock of railways is the determination of the parameters of its running gears. Among the issues related to this problem, the important task is to determine the dynamic qualities of locomotives at the design stage, taking into account the selected technical solutions in the design of running gears. At the same time, special attention is paid to the connections of the body with bogie, in particular, using the inclined rods. Methodology. Mathematical modeling is carried out by the method of numerical integration of the equations of the mathematical model of locomotive spatial oscillations to determine the dynamic loading of the mainline locomotive using the software package "Dynamics of Rail Vihicles" ("DYNRAIL". Findings. The research results show that in order to create a simple and reliable design of running gears, which will reduce maintenance and repair costs, will have low initial cost and operating costs for the whole life cycle, high traction force as close as possible to the ultimate force in traction, will make it possible to operate in the multiple traction mode, the designers and scientists should implement scientific and technical solutions. Originality. In accordance with researches authors formed general classification formation of body/bogie connections and the general classification of structures of inclined rod of locomotives. Practical value. Generalization of the results of theoretical, scientific-methodical, experimental studies aimed at further improving the running gears of long-distance locomotives of perspective structures is urgent in improving the rolling stock constructions. The research carried out by

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

    DEFF Research Database (Denmark)

    Pedersen, Niels Leergaard

    2010-01-01

    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...

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

    Directory of Open Access Journals (Sweden)

    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

  10. Firefighter burn injuries: predictable patterns influenced by turnout gear.

    Science.gov (United States)

    Kahn, Steven A; Patel, Jignesh H; Lentz, Christopher W; Bell, Derek E

    2012-01-01

    Approximately 100 firefighters suffer fatal injuries annually and tens of thousands receive nonfatal injuries. Many of these injuries require medical attention and restricted activity but may be preventable. This study was designed to elucidate etiology, circumstances, and patterns of firefighter burn injury so that further prevention strategies can be designed. In particular, modification of protective equipment, or turnout gear, is one potential strategy to prevent burn injury. An Institutional Review Board-approved retrospective review was conducted with records of firefighters treated for burn injury from 2005 to 2009. Data collected included age, gender, TBSA, burn depth, anatomic location, total hospital days per patient, etiology, and circumstances of injury. Circumstances of injury were stratified into the following categories: removal/dislodging of equipment, failure of equipment to protect, training errors, and when excessive external temperatures caused patient sweat to boil under the gear. Over the 4-year period, 20 firefighters were treated for burn injury. Mean age was 38.9 ± 8.9 years and 19 of 20 patients were male. Mean burn size was 1.1 ± 2.7% TBSA. Eighteen patients suffered second-degree burns, while two patients suffered first-degree burns. Mean length of hospitalization was 2.45 days. Scald burns were responsible for injury to 13 firefighters (65%). Flame burns caused injury to four patients (20%). Only three patients received contact burns (15%). The face was the site most commonly burned, representing 29% of injuries. The hand/wrist and ears were the next largest groups, with 23 and 16% of the injuries, respectively. Other areas burned included the neck (10%), arm (6.5%), leg (6.5%), knees (3%), shoulders (3%), and head (3%). Finally, the circumstance of injury was evaluated for each patient. Misuse and noncontiguous areas of protective equipment accounted for 14 of the 20 injuries (70%). These burns were caused when hot steam

  11. Channel Propagation Model for Train to Vehicle Alert System at 5.9 GHz using Dedicated Short Range Communication

    OpenAIRE

    Rowe, Christopher D

    2016-01-01

    The most common railroad accidents today involve collisions between trains and passenger vehicles at railroad grade crossings [1][2]. Due to the size and speed of a train, these collisions generally result in significant damage and serious injury. Despite recent efforts by projects such as Operation Lifesaver to install safety features at grade crossings, up to 80% of the United States railroad grade crossings are classified as 'unprotected' with no lights, warnings, or crossing gates [2]. F...

  12. Wear Resistance Assessment of Fluoropolymer Coated Gears

    Directory of Open Access Journals (Sweden)

    Lidia Nedeloni

    2017-11-01

    Full Text Available Power transmissions that incorporate gears dissipate a significant amount of energy and noise. Thus, any improvement in their performance contributes to reducing energy consumption and noise pollution. In recent years, the opportunities offered by conventional technologies to increase gear performance have been fully exploited. Therefore, surface depositions on gear teeth have become increasingly important technologies in achieving objectives such as: improving energy performance, providing greater protection against superficial defects, increasing load capacity and reducing acoustic emissions generated during operation. However, gear coating technologies have begun to be developed, but the investigations are still insufficient. In this study, we carried out wear resistance investigations performed on fluoropolymer coatings for different working speeds, loads and lubrication conditions. The results point out that the deterioration rate of the coating increases with the increase of the working speed and the applied load. In addition, a slight lubrication, applied at the start of testing, leads to a noticeable improvement in wear behaviour. This study represents one step further in understanding the wear process of fluoropolymer coated gears

  13. A Computational Investigation of Gear Windage

    Science.gov (United States)

    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.

  14. A ground-based magnetic survey of Frenchman Flat, Nevada National Security Site and Nevada Test and Training Range, Nevada: data release and preliminary interpretation

    Science.gov (United States)

    Phillips, Jeffrey D.; Burton, Bethany L.; Curry-Elrod, Erika; Drellack, Sigmund

    2014-01-01

    The Nevada National Security Site (NNSS, formerly the Nevada Test Site) is located in southern Nevada approximately 105 kilometers (km) (65 miles) northwest of Las Vegas. Frenchman Flat is a sedimentary basin located on the eastern edge of NNSS and extending eastward into the adjacent Nevada Test and Training Range (NTTR).

  15. D Modelling with the Samsung Gear 360

    Science.gov (United States)

    Barazzetti, L.; Previtali, M.; Roncoroni, F.

    2017-02-01

    The Samsung Gear 360 is a consumer grade spherical camera able to capture photos and videos. The aim of this work is to test the metric accuracy and the level of detail achievable with the Samsung Gear 360 coupled with digital modelling techniques based on photogrammetry/computer vision algorithms. Results demonstrate that the direct use of the projection generated inside the mobile phone or with Gear 360 Action Direction (the desktop software for post-processing) have a relatively low metric accuracy. As results were in contrast with the accuracy achieved by using the original fisheye images (front and rear facing images) in photogrammetric reconstructions, an alternative solution to generate the equirectangular projections was developed. A calibration aimed at understanding the intrinsic parameters of the two lenses camera, as well as their relative orientation, allowed one to generate new equirectangular projections from which a significant improvement of geometric accuracy has been achieved.

  16. Improving backdrivability in geared rehabilitation robots.

    Science.gov (United States)

    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%.

  17. On the Correlation of Specific Film Thickness and Gear Pitting Life

    Science.gov (United States)

    Krantz, Timothy L.

    2015-01-01

    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 defined as the ratio of lubricant film thickness to the composite surface roughness. It can be difficult to combine results of studies to create a cohesive and comprehensive dataset. In this work gear surface fatigue lives for a wide range of specific film values were studied using tests done with common rigs, speeds, lubricant temperatures, and test procedures. This study includes previously reported data, results of an additional 50 tests, and detailed information from lab notes and tested gears. The dataset comprised 258 tests covering specific film values (0.47 to 5.2). The experimentally determined surface fatigue lives, quantified as 10-percent life estimates, ranged from 8.7 to 86.8 million cycles. The trend is one of increasing life for increasing specific film. The trend is nonlinear. The observed trends were found to be in good agreement with data and recommended practice for gears and bearings. The results obtained will perhaps allow for the specific film parameter to be used with more confidence and precision to assess gear surface fatigue for purpose of design, rating, and technology development.

  18. Investigation of pitting load-carrying capacity of case carburized gears with grease lubrication; Untersuchung der Gruebchentragfaehigkeit einsatzgehaerteter Zahnradpaarungen bei Schmierung mit Getriebefetten

    Energy Technology Data Exchange (ETDEWEB)

    Hochmann, Michael; Michaelis, Klaus; Hoehn, Bernd-Robert

    2009-07-15

    In this research project the influence of flow greases NLGI 00 on the pitting load-carrying capacity of case carburized gears is systematically investigated. In the range of limited life and infinite life the pitting life time and the pitting load-carrying capacity of gear greases in NLGI 00 on the basis of a base oil of ISO VG 680 is lower than that of the respective base oil in the test method C-PT/8.3/90. This is caused by the unfavourable heat dissipation and the higher bulk temperature of the test gears with grease lubrication. In the test method C-PT/5.5/90 with reduced circumferential speed gear grease in NLGI 00 and its base oil ISO VG 680 show comparable bulk temperatures and pitting life times. In the range of limited life the pitting life time of gear greases in NLGI 00 correlates with the kinematic viscosity of the base oil. But in the range of infinite life the base oil viscosity of gear greases in NLGI 00 influences the pitting load-carrying capacity only slightly. For gear greases in NLGI 00 a good comparability can be stated for the experimental and the calculated pitting load-carrying capacity with the calculation according to Knauer if appropriate friction coefficients, e.g. measured values are used. In the range of boundary friction and high lubricant temperatures the thickener of gear greases in NLGI 00 decreases the friction in comparison to the base oil. (orig.)

  19. MODERNIZATION OF TRACKED VEHICLE RUNNING GEARS

    OpenAIRE

    V. A. Korobkin; A. Ya. Kotlobai; V. P. Boikov; A. A. Kotlobai; V. F. Tamelo

    2013-01-01

    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...

  20. Environmental Assessment: Target Upgrades on Leach Lake Tactical Range at the National Training Center, Fort Irwin, California

    Science.gov (United States)

    2006-06-01

    northern extent of its range includes the Coso Range and the Argus Range (Inyo County) in the northwest and the Avawatz Mountains and the Soda...sections to provide a comparative framework for evaluating the potential impacts on individual resources of the Proposed Action and No Action Al- ternative

  1. Improvement of vibroacoustic properties of toothed gears through constructional modifications of gear teeth

    Directory of Open Access Journals (Sweden)

    Andrzej WIECZOREK

    2009-01-01

    Full Text Available The paper draws attention to methods of minimizing values of vibroacoustic factors by reducing the sources. In the case of toothed gears such causes include, first of all, deviations in workmanship, excitations generated when teeth move in and out of mesh, as well as mesh stiffness variations. The paper presents results of experimental research on vibroacoustic properties of gear wheels with modified and non-modified high-profile teeth. Basing on these results, it was determined that the best results in counteracting vibrations and noise are obtained by using jointly an increased gear contact ratio and a tooth profile modification.

  2. 76 FR 4870 - Taking and Importing Marine Mammals; U.S. Navy Training in the Southern California Range Complex

    Science.gov (United States)

    2011-01-27

    ... required that the Navy update the ICMP Plan to reflect development in three areas, specifically: (1... for marine species monitoring, which may reflect monitoring differences in some Navy training areas..., 2011. Helen M. Golde, Deputy Director, Office of Protected Resources, National Marine Fisheries Service...

  3. 76 FR 30552 - Taking and Importing Marine Mammals: U.S. Navy Training in the Virginia Capes Range Complex and...

    Science.gov (United States)

    2011-05-26

    ..., identified by 0648-BB03, by any one of the following methods: Electronic Submissions: Submit all electronic...). Attachments to electronic comments will be accepted in Microsoft Word, Excel, WordPerfect, or Adobe PDF file... certification includes critically important anti- submarine warfare that requires training on the use and...

  4. Plasma Fairings for Quieting Aircraft Landing Gear Noise Project

    Data.gov (United States)

    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 bluff...

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

    Science.gov (United States)

    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.

  6. Mathematical Modelling of Involute Spur Gears Manufactured by Rack Cutter

    Directory of Open Access Journals (Sweden)

    Tufan Gürkan YILMAZ

    2016-05-01

    Full Text Available In this study, mathematical modelling of asymmetric involute spur gears was situated in by Litvin approach. In this context, firstly, mathematical expressions of rack cutter which manufacture asymmetric involute spur gear, then mathematical expression of asymmetric involute spur gear were obtained by using differential geometry, coordinate transformation and gear theory. Mathematical expressions were modelled in MATLAB and output files including points of involute spur gear’s teeth were designed automatically thanks to macros.

  7. Characterization and Fate of Gun and Rocket Propellant Residues on Testing and Training Ranges: Interim Report 2

    Science.gov (United States)

    2010-12-01

    Recherche Scientifique Centre Eau, Terre, et Environnement 290, de la Couronne Québec, Québec G1K 9A9 CANADA Peter Woods British Army Training...series of large-column tests have been completed at Institut National de la Recherche Scientifique – Eau, Terre et Environnement . The columns were...Eau, Terre, et Environnement (INRS-ETE). Four lysimeters were used for the sampling of interstitial water (depths: 10, 30, 60 cm, and background

  8. 50 CFR 640.22 - Gear and diving restrictions.

    Science.gov (United States)

    2010-10-01

    ... 50 Wildlife and Fisheries 8 2010-10-01 2010-10-01 false Gear and diving restrictions. 640.22 Section 640.22 Wildlife and Fisheries FISHERY CONSERVATION AND MANAGEMENT, NATIONAL OCEANIC AND... ATLANTIC Management Measures § 640.22 Gear and diving restrictions. (a) Prohibited gear and methods. (1) A...

  9. 50 CFR 648.51 - Gear and crew restrictions.

    Science.gov (United States)

    2010-10-01

    ... strengtheners, ropes, lines, or chafing gear, on the top of a trawl net, except that one splitting strap and one... top) possessed or used by vessels fishing with scallop dredge gear shall not be smaller than 10-inch... restrictions. No chafing gear or cookies shall be used on the top of a scallop dredge. (ii) Link restrictions...

  10. Gear cutting tools fundamentals of design and computation

    CERN Document Server

    Radzevich, Stephen P

    2010-01-01

    Presents the DG/K-based method of surface generation, a novel and practical mathematical method for designing gear cutting tools with optimal parameters. This book proposes a scientific classification for the various kinds of the gear machining meshes, discussing optimal designs of gear cutting tools.

  11. Analytical and Experimental Vibration Analysis of a Faulty Gear System

    Science.gov (United States)

    Choy, F. K.; Braun, M. J.; Polyshchuk, V.; Zakrajsek, J. J.; Townsend, D. P.; Handschuh, R. F.

    1994-01-01

    A comprehensive analytical procedure was developed for predicting faults in gear transmission systems under normal operating conditions. A gear tooth fault model is developed to simulate the effects of pitting and wear on the vibration signal under normal operating conditions. The model uses changes in the gear mesh stiffness to simulate the effects of gear tooth faults. The overall dynamics of the gear transmission system is evaluated by coupling the dynamics of each individual gear-rotor system through gear mesh forces generated between each gear-rotor system and the bearing forces generated between the rotor and the gearbox structure. The predicted results were compared with experimental results obtained from a spiral bevel gear fatigue test rig at NASA Lewis Research Center. The Wigner-Ville distribution (WVD) was used to give a comprehensive comparison of the predicted and experimental results. The WVD method applied to the experimental results were also compared to other fault detection techniques to verify the WVD's ability to detect the pitting damage, and to determine its relative performance. Overall results show good correlation between the experimental vibration data of the damaged test gear and the predicted vibration from the model with simulated gear tooth pitting damage. Results also verified that the WVD method can successfully detect and locate gear tooth wear and pitting damage.

  12. 50 CFR 600.510 - Gear avoidance and disposal.

    Science.gov (United States)

    2010-10-01

    ... fishery in which the FFV is engaged. (b) Gear conflicts. The operator of each FFV that is involved in a conflict or that retrieves the gear of another vessel must immediately notify the appropriate USCG..., fishing gear, net scraps, bale straps, plastic bags, oil drums, petroleum containers, oil, toxic chemicals...

  13. Molecular Dynamics Simulation of Carbon Nanotube Based Gears

    Science.gov (United States)

    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.

  14. 46 CFR 182.610 - Main steering gear.

    Science.gov (United States)

    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 service...

  15. 30 CFR 75.1404 - Automatic brakes; speed reduction gear.

    Science.gov (United States)

    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 devices...

  16. 46 CFR 167.65-25 - Steering gear tests.

    Science.gov (United States)

    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 of...

  17. 46 CFR 61.20-1 - Steering gear.

    Science.gov (United States)

    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 Inspections...

  18. Automotive gear oil lubricant from soybean oil

    Science.gov (United States)

    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...

  19. Handcycling : different modes and gear ratios

    NARCIS (Netherlands)

    van der Woude, L H; Bosmans, I; Bervoets, B; Veeger, DirkJan (H. E. J.)

    2001-01-01

    Handrim wheelchair propulsion is a straining form of ambulation. In contrast, arm crank exercise in laboratory settings has shown a higher degree of gross mechanical efficiency and increased levels of peak power output. Moreover, arm crank exercise can be conducted at different gear ratios and in

  20. Analysis of landing gear noise during approach

    NARCIS (Netherlands)

    Merino Martinez, R.; Snellen, M.; Simons, D.G.

    2016-01-01

    Airframe noise is becoming increasingly important during approach, even reaching higher noise levels than the engines in some cases. More people are a_ected due to low ight altitudes and _xed tra_c routing associated with typical approaches. For most air- craft types, the landing gear system is a

  1. Predicting lethal entanglements as a consequence of drag from fishing gear.

    Science.gov (United States)

    van der Hoop, Julie M; Corkeron, Peter; Henry, Allison G; Knowlton, Amy R; Moore, Michael J

    2017-02-15

    Large whales are frequently entangled in fishing gear and sometimes swim while carrying gear for days to years. Entangled whales are subject to additional drag forces requiring increased thrust power and energy expenditure over time. To classify entanglement cases and aid potential disentanglement efforts, it is useful to know how long an entangled whale might survive, given the unique configurations of the gear they are towing. This study establishes an approach to predict drag forces on fishing gear that entangles whales, and applies this method to ten North Atlantic right whale cases to estimate the resulting increase in energy expenditure and the critical entanglement duration that could lead to death. Estimated gear drag ranged 11-275N. Most entanglements were resolved before critical entanglement durations (mean±SD 216±260days) were reached. These estimates can assist real-time development of disentanglement action plans and U.S. Federal Serious Injury assessments required for protected species. Copyright © 2016 Elsevier Ltd. All rights reserved.

  2. Contactless Mechanical Components: Gears, Torque Limiters and Bearings

    Directory of Open Access Journals (Sweden)

    Jose Luis Perez-Diaz

    2014-12-01

    Full Text Available Contactless mechanical components are mechanical sets for conversion of torque/speed, whose gears and moving parts do not touch each other, but rather they provide movement with magnets and magnetic materials that exert force from a certain distance. Magneto-mechanical transmission devices have several advantages over conventional mechanisms: no friction between rotatory elements (no power losses or heat generation by friction so increase of efficiency, no lubrication is needed (oil-free mechanisms and no lubrication auxiliary systems, reduced maintenance (no lubricant so no need of oil replacements, wider operational temperature ranges (no lubricant evaporation or freezing, overload protection (if overload occurs magnet simply slides but no teeth brake, through-wall connection (decoupling of thermal and electrical paths and environmental isolation, larger operative speeds (more efficient operative conditions, ultralow noise and vibrations (no contact no noise generation. All these advantages permit us to foresee in the long term several common industrial applications in which including contactless technology would mean a significant breakthrough for their performance. In this work, we present three configurations of contactless mechanical passive components: magnetic gears, magnetic torque limiters and superconducting magnetic bearings. We summarize the main characteristic and range of applications for each type; we show experimental results of the most recent developments showing their performance.

  3. Effect of task specific training and wrist-fingers extension splint on hand joints range of motion and function after stroke.

    Science.gov (United States)

    Khallaf, Mohamed E; Ameer, Mariam A; Fayed, Eman E

    2017-01-01

    Most stroke patients experience hand impairments that can result in persistent limitations in daily activities. This study aimed at estimating the immediate and retention effects of task specific training and wrist/fingers extension splint on hand joints range of motion and function after stroke. Twenty-four right handed patients with first ever stroke represented the sample of the study. The participants were randomly assigned into two equal groups. The study group received task specific exercises five times a week for an hour concurrently with wrist/fingers extension splint which was used two hours for each three hours (day and night) excluding exercises and sleeping hours for 16 weeks. The control group received traditional passive stretch and range of motion exercises. Manual dexterity and upper limb function were assessed by nine holes peg test and Fugl-Meyer upper extremity and hand. Goniometry was used for measuring wrist, metacarpophalangeal, thumb carpometacarpal joints active range of motion. Significant improvements were observed in nine holes peg test, Fugl-Meyer upper extremity and hand scores and ranges of motion at post-intervention and follow-up compared to pre-intervention at P≤0.05. The results of this study provide an evidence that task specific training and wrist/fingers extension splint are effective in improving fingers dexterity, upper extremity function and wrist/hand range of motion.

  4. Particularidades del cálculo de engranajes plásticos. // Particularities of plastic gear calculation.

    Directory of Open Access Journals (Sweden)

    J. L. Moya Rodríguez

    2003-05-01

    Full Text Available En los últimos tiempos los materiales plásticos han tenido una proliferación en todos los campos de la Industria Mecánica,debido esencialmente a su bajo costo y a las mejoras de las propiedades mecánicas que se han ido logrando. En el casoparticular de las transmisiones por engranajes existe una gran cantidad de estos materiales que pueden ser usados y dehecho se utilizan para la fabricación de ruedas dentadas de características muy disímiles. En la literatura científica existemuy poca información disponible sobre las fallas de engranajes plásticos, métodos de calculo a resistencia y posiblesmateriales a emplear con sus respectivas propiedades mecánicas. Inclusive este tema no se aborda en los currículos deestudio tradicionales en Ibero-América. Queda mucho por discutir aun acerca del empleo de las correcciones del dentado enestas ruedas dentadas plásticas. En el presente trabajo se hace un análisis de los materiales, características, estudio de lasfallas principales, métodos de calculo y ejemplos de aplicación de los engranajes plásticos.Palabras claves: Plásticos, engranes, perfil dentado.__________________________________________________________________________Abstract.Recently the use of plastic materials has been growing up due to their low cost and the improvements achieved on theirmechanical properties. In the particular case of gear transmissions there are great quantities of polymers that can be usedfor gears. Plastic gears are powerful means of cutting drive cost, weight, noise, and wear. Plastic gears also open newopportunities for smaller and more efficient transmissions. There is few information in Scientific literature about plasticgears failures, designing methods and materials. Most engineering reference books are desicated to steel gears but there areremarkably silent about plastic gears. Design methods for plastic gears and gear trains must be modernized, because muchof the information available is derived

  5. Research on the Design and Modification of Asymmetric Spur Gear

    Directory of Open Access Journals (Sweden)

    Xiaohe Deng

    2015-01-01

    Full Text Available A design method for the geometric shape and modification of asymmetric spur gear was proposed, in which the geometric shape and modification of the gear can be obtained directly according to the rack-cutter profile. In the geometric design process of the gear, a rack-cutter with different pressure angles and fillet radius in the driving side and coast side was selected, and the generated asymmetric spur gear profiles also had different pressure angles and fillets accordingly. In the modification design of the gear, the pressure angle modification of rack-cutter was conducted firstly and then the corresponding modified involute gear profile was obtained. The geometric model of spur gears was developed using computer-aided design, and the meshing process was analyzed using finite element simulation method. Furthermore, the transmission error and load sharing ratio of unmodified and modified asymmetric spur gears were investigated. Research results showed that the proposed gear design method was feasible and desired spur gear can be obtained through one time rapid machining by the method. Asymmetric spur gear with better transmission characteristic can be obtained via involute modification.

  6. Experimental investigation of active loads control for aircraft landing gear

    Science.gov (United States)

    Mcgehee, J. R.; Dreher, R. C.

    1982-01-01

    Aircraft dynamic loads and vibrations resulting from landing impact and from runway and taxiway unevenness are recognized as significant in causing fatigue damage, dynamic stress on the airframe, crew and passenger discomfort, and reduction of the pilot's ability to control the aircraft during ground operations. One potential method for improving operational characteistics of aircraft on the ground is the application of active control technology to the landing gears to reduce ground loads applied to the airframe. An experimental investigation was conducted which simulated the landing dynamics of a light airplane to determine the feasibility and potential of a series hydraulic active control main landing gear. The experiments involved a passive gear and an active control gear. Results of this investigation show that a series hydraulically controlled gear is feasible and that such a gear is very effective in reducing the loads transmitted by the gear to the airframe during ground operations.

  7. Active control landing gear for ground load alleviation

    Science.gov (United States)

    Mcgehee, J. R.; Morris, D. L.

    1985-01-01

    Results of analytical and experimental investigations of a series-hydraulic active control landing gear show that such a gear is feasible when using existing hardware and is very effective in reducing loads, relative to those generated by a conventional (passive year) gear, transmitted to the airframe during ground operations. Analytical results obtained from an active gear, flexible aircraft, take-off and landing analysis are in good agreement with experimental data and indicate that the analysis is a valid tool for study and initial design of series-hydraulic active control landing gears. An analytical study of a series-hydraulic active control main landing gear on an operational supersonic airplane shows that the active gear has the potential for improving the dynamic response of the aircraft and significantly reducing structural fatigue damage during ground operations.

  8. Influence of Gear Design Parameters on Gearbox Radiated Noise

    Science.gov (United States)

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

    1994-01-01

    Spur and helical gears were tested in the NASA gear-noise rig to compare the noise produced by different gear designs. Sound power measurements were performed under controlled conditions for a matrix of operating conditions. Sound power was computed from near-field acoustic intensity scans taken just above the top surface of the gearbox. Test gears included four spur and five helical gear designs. The gears were designed to be as nearly identical as possible except for deliberate differences in tooth geometry and contact ratio. Test results are presented as a function of the gear design and operating conditions in the form of sound power charts and as narrow-band spectra.

  9. The Drag of Airplane Wheels, Wheel Fairings and Landing Gears. 2. Nonretractable and Partly Retractable Landing Gears,

    Science.gov (United States)

    1935-01-01

    fairings were tested when in the mately 3,000 pounds weight. The present report givs landing condition as well as in the partly retracted the results of...weight. The tween the nacelle and the gear as well as for the effect landing gears were mounted on a wing of 5foot chord_ of the gear on the aerodynamic...was 1)refiously noted ill 06 .. 6 the case without tiliet on landing gear A. Vahles of drag (die to hlnling gear 1) whell partly Sretracted into, the

  10. 75 FR 4047 - Taking and Importing Marine Mammals; U.S. Navy Training in the Southern California Range Complex

    Science.gov (United States)

    2010-01-26

    ... death, the ultimate status of the other whale is unknown) a large whale, one of which was later identified as a fin whale. Of note, in both cases the Navy was in compliance with the mitigation and... monitoring measures, if appropriate. Whale Strikes in 2009 In their SOCAL Range Complex Environmental Impact...

  11. Electron Beam Welding of Gear Wheels by Splitted Beam

    Science.gov (United States)

    Dřímal, Daniel

    2014-06-01

    This contribution deals with the issue of electron beam welding of high-accurate gear wheels composed of a spur gearing and fluted shaft joined with a face weld for automotive industry. Both parts made of the high-strength low-alloy steel are welded in the condition after final machining and heat treatment, performed by case hardening, whereas it is required that the run-out in the critical point of weldment after welding, i. e. after the final operation, would be 0.04 mm max.. In case of common welding procedure, cracks were formed in the weld, initiated by spiking in the weld root. Crack formation was prevented by the use of an interlocking joint with a rounded recess and suitable welding parameters, eliminating crack initiation by spiking in the weld root. Minimisation of the welding distortions was achieved by the application of tack welding with simultaneous splitting of one beam into two parts in the opposite sections of circumferential face weld attained on the principle of a new system of controlled deflection with digital scanning of the beam. This welding procedure assured that the weldment temperature after welding would not be higher than 400 °C. Thus, this procedure allowed achieving the final run-outs in the critical point of gearwheels within the maximum range up to 0.04 mm, which is acceptable for the given application. Accurate optical measurements did not reveal any changes in the teeth dimensions.

  12. Interventions geared towards strengthening the health system of Namibia through the integration of palliative care

    Science.gov (United States)

    Freeman, Rachel; Luyirika, Emmanuel BK; Namisango, Eve; Kiyange, Fatia

    2016-01-01

    The high burden of non-communicable diseases and communicable diseases in Africa characterised by late presentation and diagnosis makes the need for palliative care a priority from the point of diagnosis to death and through bereavement. Palliative care is an intervention that requires a multidisciplinary team to address the multifaceted needs of the patient and family. Thus, its development takes a broad approach that involves engaging all key stakeholders ranging from policy makers, care providers, educators, the public, patients, and families. The main focus of stakeholder engagement should address some core interventions geared towards improving knowledge and awareness, strengthening skills and attitudes about palliative care. These interventions include educating health and allied healthcare professionals on the palliative care-related problems of patients and best practices for care, explaining palliative care as a clinical and holistic discipline and demonstrating its effectiveness, the need to include palliative care into national policies, strategic plans, training curriculums of healthcare professionals and the engagement of patients, families, and communities. Interventions from a five-year programme that was aimed at strengthening the health system of Namibia through the integration of palliative care for people living with HIV and AIDS and cancer in Namibia are shared. This article illustrates how a country can implement the World Health Organisation’s public health strategy for developing palliative care services, which recommends four pillars: government policy, education, drug availability, and implementation. PMID:27563348

  13. Geared Topological Metamaterials with Tunable Mechanical Stability

    Directory of Open Access Journals (Sweden)

    Anne S. Meeussen

    2016-11-01

    Full Text Available The classification of materials into insulators and conductors has been shaken up by the discovery of topological insulators that conduct robustly at the edge but not in the bulk. In mechanics, designating a material as insulating or conducting amounts to asking if it is rigid or floppy. Although mechanical structures that display topological floppy modes have been proposed, they are all vulnerable to global collapse. Here, we design and build mechanical metamaterials that are stable and yet capable of harboring protected edge and bulk modes, analogous to those in electronic topological insulators and Weyl semimetals. To do so, we exploit gear assemblies that, unlike point masses connected by springs, incorporate both translational and rotational degrees of freedom. Global structural stability is achieved by eliminating geometrical frustration of collective gear rotations extending through the assembly. The topological robustness of the mechanical modes makes them appealing across scales from engineered macrostructures to networks of toothed microrotors of potential use in micromachines.

  14. Aeroacoustic Analysis of a Simplified Landing Gear

    Science.gov (United States)

    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.

  15. Surface contact fatigue failures in gears

    CSIR Research Space (South Africa)

    Fernandes, PJL

    1997-06-01

    Full Text Available of subsurface cracks under pure rolling conditions. Surface contact fatigue failures in gears 101 rolling contact fatigue leads to the formation of a microstructural feature referred to as "butterfly wings" \\[3\\]. These are formed.... Depending on the relative velocities of the contacting bodies, rolling and sliding may occur in the same direction*- positive sliding--or in opposite directions negative sliding. The effect of the latter is that the surface...

  16. Gear distortion analysis due to heat treatment process

    Science.gov (United States)

    Guterres, Natalino F. D. S.; Rusnaldy, Widodo, Achmad

    2017-01-01

    One way to extend the life time of the gear is minimizing the distortion during the manufacturing process. One of the most important processes in manufacturing to produce gears is heat treatment process. The purpose of this study is to analyze the distortion of the gear after heat treatment process. The material of gear is AISI 1045, and it was designed with the module (m) 1.75, and a number of teeth (z) 29. Gear was heat-treated in the furnace at a temperature of 800°C, holding time of 30 minutes, and then quenched in water. Furthermore, surface hardening process was also performed on gear teeth at a temperature of 820°C and holding time of 35 seconds and the similar procedure of analysis was conducted. The hardness of gear after heat treatment average 63.2 HRC and the teeth surface hardness after gear to induction hardening was 64.9 HRC at the case depth 1 mm. The microstructure of tested gear are martensitic and pearlite. The highest distortion on tooth thickness to upper than 0.063 can cause high precision at the tooth contact is not appropriate. Besides the shrinkage of tooth thickness will also affect to contact angle because the size of gear tolerance was not standardized.

  17. DESIGN IMPROVEMENT OF THE LOCOMOTIVE RUNNING GEARS

    Directory of Open Access Journals (Sweden)

    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

  18. A1c Gear: Laboratory quality HbA1c measurement at the point of care.

    Science.gov (United States)

    Ejilemele, Adetoun; Unabia, Jamie; Ju, Hyunsu; Petersen, John R

    2015-05-20

    HbA1c is an important part of assessing the diabetic control and since the use of point-of-care devices for monitoring HbA1c is increasing, it is important to determine how these devices compare to the central laboratory. One hundred and twenty patient samples were analyzed on the Bio-Rad Variant™II and one POC analyzer (Sakae A1c Gear). Three patient sample pools containing ~5%, ~7%, and ~10% HbA1c levels were run over 20 days. Three reagent lots and three instruments were evaluated for the A1c Gear. The 120 patient samples showed strong correlation (R(2)>0.989) when compared to the Variant™II with means=8.06% and 7.81%, for Variant IIand A1c Gear, respectively. Changing reagent lots or instruments had no impact for the A1c Gear. The ~5%, ~7%, and ~10% pools within-run and between-run imprecision was between 0.87-1.33% and 1.03-1.32%, and 1.41-2.35% and 1.24-1.89% with total imprecision of 1.67-2.35% and 1.61-2.31% for the A1c Gear and Variant II, respectively. The A1c Gear showed a small negative bias (0.25% HbA1c) across HbA1c measurement ranges of Gear meets the criteria of total CV Gear can give results as precise as the laboratory at the POC. Copyright © 2015. Published by Elsevier B.V.

  19. Magnet-Sleeve-Sealed Mini Trochoidal-Gear Pump Prototype with Polymer Composite Gear

    Directory of Open Access Journals (Sweden)

    Pedro Javier Gamez-Montero

    2017-09-01

    Full Text Available The trochoidal-gear technology has been growing in groundbreaking fields. Forthcoming applications are demanding to this technology a step forward in the conceiving stage of positive displacement machines. The compendium of the qualities and the inherent characteristics of trochoidal-gear technology, especially towards the gerotor pump, together with scale/size factor and magnetic-driven transmission has led to the idea of a magnet-sleeve-sealed variable flow mini trochoidal-gear pump. From its original concept, to the last phase of the design development, the proof of concept, this new product will intend to overcome problems such as noise, vibration, maintenance, materials, and dimensions. The paper aims to show the technological path followed from the concept, design, and model, to the manufacture of the first prototype, where the theoretical and numerical approaches are not always directly reflected in the prototype performance results. Early in the design process, from a standard-commercial sintered metal mini trochoidal-gear unit, fundamental characteristics and dimensional limitations have been evaluated becoming the strategic parameters that led to its configuration. The main technical challenge to confront is being sealed with non-exterior driveshaft, ensuring that the whole interior is filled and wetted with working fluid and helping the hydrodynamic film formation, the pumping effect, and the heat dissipation. Subsequently, the mini pump architecture, embodiment, methodology, materials, and manufacture are presented. The trend of applications of polymer composite materials and their benefits wanted to be examined with this new mini pump prototype, and a pure polyoxymethylene mini trochoidal-gear set has been designed and manufactured. Finally, both the sintered and the polymer trochoidal-gear units have been experimentally tested in an in-house full-instrumented mini test bench. Although the main goal of the presented work is the

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

    Directory of Open Access Journals (Sweden)

    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.

  1. Assessment of Gear Damage Monitoring Techniques Using Vibration Measurements

    Science.gov (United States)

    Wang, Wilson Q.; Ismail, Fathy; Farid Golnaraghi, M.

    2001-09-01

    Each gear damage monitoring technique has its merits and limitations. This paper experimentally investigates the sensitivity and robustness of the currently well-accepted techniques: phase and amplitude demodulation, beta kurtosis and wavelet transform. Four gear test cases were used: healthy gears, cracked, filed and chipped gears. The vibration signal was measured on the gearbox housing and processed, online, under three filtering conditions: general signal average, overall residual and dominant meshing frequency residual. Test results show that beta kurtosis is a very reliable time-domain diagnostic technique. Phase modulation is very sensitive to gear imperfections, but other information should be used to confirm its diagnostic results. Continuous wavelet transform provides a good visual inspection especially when residual signals are used. The diagnosis based only on dominant meshing frequency residual, however, should not be used independently for gear health condition monitoring, it may give false alarms.

  2. Bifurcation phenomena in internal dynamics of gear systems

    Directory of Open Access Journals (Sweden)

    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.

  3. Fault Analysis on Bevel Gear Teeth Surface Damage of Aeroengine

    Science.gov (United States)

    Cheng, Li; Chen, Lishun; Li, Silu; Liang, Tao

    2017-12-01

    Aiming at the trouble phenomenon for bevel gear teeth surface damage of Aero-engine, Fault Tree of bevel gear teeth surface damage was drawing by logical relations, the possible cause of trouble was analyzed, scanning electron-microscope, energy spectrum analysis, Metallographic examination, hardness measurement and other analysis means were adopted to investigate the spall gear tooth. The results showed that Material composition, Metallographic structure, Micro-hardness, Carburization depth of the fault bevel gear accord with technical requirements. Contact fatigue spall defect caused bevel gear teeth surface damage. The small magnitude of Interference of accessory gearbox install hole and driving bevel gear bearing seat was mainly caused. Improved measures were proposed, after proof, Thermoelement measures are effective.

  4. GEAR: genomic enrichment analysis of regional DNA copy number changes.

    Science.gov (United States)

    Kim, Tae-Min; Jung, Yu-Chae; Rhyu, Mun-Gan; Jung, Myeong Ho; Chung, Yeun-Jun

    2008-02-01

    We developed an algorithm named GEAR (genomic enrichment analysis of regional DNA copy number changes) for functional interpretation of genome-wide DNA copy number changes identified by array-based comparative genomic hybridization. GEAR selects two types of chromosomal alterations with potential biological relevance, i.e. recurrent and phenotype-specific alterations. Then it performs functional enrichment analysis using a priori selected functional gene sets to identify primary and clinical genomic signatures. The genomic signatures identified by GEAR represent functionally coordinated genomic changes, which can provide clues on the underlying molecular mechanisms related to the phenotypes of interest. GEAR can help the identification of key molecular functions that are activated or repressed in the tumor genomes leading to the improved understanding on the tumor biology. GEAR software is available with online manual in the website, http://www.systemsbiology.co.kr/GEAR/.

  5. Landing Gear Door Liners for Airframe Noise Reduction

    Science.gov (United States)

    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.

  6. GEARS: An Enterprise Architecture Based On Common Ground Services

    Science.gov (United States)

    Petersen, S.

    2014-12-01

    Earth observation satellites collect a broad variety of data used in applications that range from weather forecasting to climate monitoring. Within NOAA the National Environmental Satellite Data and Information Service (NESDIS) supports these applications by operating satellites in both geosynchronous and polar orbits. Traditionally NESDIS has acquired and operated its satellites as stand-alone systems with their own command and control, mission management, processing, and distribution systems. As the volume, velocity, veracity, and variety of sensor data and products produced by these systems continues to increase, NESDIS is migrating to a new concept of operation in which it will operate and sustain the ground infrastructure as an integrated Enterprise. Based on a series of common ground services, the Ground Enterprise Architecture System (GEARS) approach promises greater agility, flexibility, and efficiency at reduced cost. This talk describes the new architecture and associated development activities, and presents the results of initial efforts to improve product processing and distribution.

  7. Differences in End Range of Motion Vertical Jump Kinetic and Kinematic Strategies Between Trained Weightlifters and Elite Short Track Speed Skaters.

    Science.gov (United States)

    Haug, William B; Spratford, Wayne; Williams, Kym J; Chapman, Dale W; Drinkwater, Eric J

    2015-09-01

    The purpose of this investigation was to identify differences in end range of motion (ROM) kinetic and kinematic strategies between highly resistance and vertical jump-trained athletes and controls. Weightlifters (WL: n = 4), short track speed skaters (STSS: n = 5), and nonresistance-trained controls (C: n = 6) performed 6 standing vertical squat jumps (SJ) and countermovement jumps (CMJ) without external resistance. Jump testing was performed using 3-dimensional marker trajectories captured with a 15-camera motion analysis system synchronized with 2 in-ground force plates. During SJ, there were large effects for the difference in time before toe off of peak vertical velocity between WL to STSS and C (ES: -1.43; ES: -1.73, respectively) and for the decrease between peak and toe off vertical velocity (ES: -1.28; ES: -1.71, respectively). During CMJ, there were large effects for the difference in time before toe off of peak vertical velocity between WL to STSS and C (ES: -1.28; ES: -1.53, respectively) and for decrease between peak and toe off vertical velocity (ES: -1.03; ES: -1.59, respectively). Accompanying these differences for both jump types were large effects for time of joint deceleration before toe off for all lower body joints between WL compared with C with large effects between WL and STSS at the hip and between STSS and C at the ankle. These findings suggest that the end ROM kinetic and kinematic strategy used during jumping is group-specific in power-trained athletes, with WL exhibiting superior strategies as compared with resistance- and jump-trained STSS.

  8. High-intensity, unilateral resistance training of a non-paretic muscle group increases active range of motion in a severely paretic upper extremity muscle group after stroke.

    Directory of Open Access Journals (Sweden)

    M. A. Urbin

    2015-05-01

    Full Text Available Limited rehabilitation strategies are available for movement restoration when paresis is too severe following stroke. Previous research has shown that high-intensity resistance training of one muscle group enhances strength of the homologous, contralateral muscle group in neurologically-intact adults. How this cross education phenomenon might be exploited to moderate severe weakness in an upper extremity muscle group after stroke is not well understood. The primary aim of this study was to examine adaptations in force-generating capacity of severely paretic wrist extensors resulting from high-intensity, dynamic contractions of the non-paretic wrist extensors. A secondary, exploratory aim was to probe neural adaptations in a subset of participants from each sample using a single-pulse, transcranial magnetic stimulation protocol. Separate samples of neurologically-intact controls (n=7 and individuals > 4 months post stroke (n=6 underwent 16 sessions of training. Following training, one-repetition maximum of the untrained wrist extensors in the control group and active range of motion of the untrained, paretic wrist extensors in the stroke group were significantly increased. No changes in corticospinal excitability, intracortical inhibition or interhemispheric inhibition were observed in control participants. Both stroke participants who underwent TMS testing, however, exhibited increased voluntary muscle activation following the intervention. In addition, motor-evoked potentials that were unobtainable prior to the intervention were readily elicited afterwards in a stroke participant. Results of this study demonstrate that high-intensity resistance training of a non-paretic upper extremity muscle group can enhance voluntary muscle activation and force-generating capacity of a severely paretic muscle group after stroke. There is also preliminary evidence that corticospinal adaptations may accompany these gains.

  9. The theory and practice of worm gear drives

    CERN Document Server

    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

  10. Diagnostics of power transmissions system with tooth gear

    Directory of Open Access Journals (Sweden)

    Grzegorz WOJNAR

    2008-01-01

    Full Text Available This paper presents results of laboratory tests that were aimed at detecting early stages of various faults in toothed wheels by measurement and analysis of transverse vibration speed of the transmission gear shafts. In experimental investigation, cracking of the root tooth and chipping of the tooth were detected. The laser vibrometer Ometron VH300+ was used for non-contact measurement of shaft transversal vibration speed. Gear vibrations were recorded in selected points of gear housing and gear shafts at different speeds and gear loads. Results were analyzed and compared but in this paper is presented only selected examples. This paper shows that on the basis of the transverse vibration speed of transmission gear shafts, it is possible to detect defects at an earlier stage than on the basis of the housing vibration accelerations. In the case of measuring gear shaft vibration velocity, the way of the signal generated by the defect of a gear wheel (or bearing is shortened as well as the influence of composed transmittance of the bearing-gear housing system is eliminated. WV time-frequency analysis and complex continuous wavelet transformations were used for detection. The authors introduced a measure of local tooth damage, which was proportional to the size of damage. The results of research presented in this paperconfirmed that the defect's measure is very sensitive to the development of teeth faults.

  11. Turbine Engine with Differential Gear Driven Fan and Compressor

    Science.gov (United States)

    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.

  12. High efficiency gears synthesis by avoid the interferences

    Directory of Open Access Journals (Sweden)

    Florian Ion Tiberiu Petrescu

    2014-05-01

    Full Text Available Normal 0 false false false EN-US X-NONE X-NONE MicrosoftInternetExplorer4 The paper presents an original method to determine the efficiency of the gear, the forces of the gearing, the velocities and the powers. It is analyzing the influence of a few parameters concerning gear efficiency. These parameters are: z1 - the number of teeth for the primary wheel of gear; z2 - the number of teeth of the secondary wheel of gear; alpha0 - the normal pressure angle on the divided circle; beta - the inclination angle. With the relations presented in this paper, it can synthesize the gear’s mechanisms. Today, the gears are present everywhere, in the mechanical’s world (In vehicle’s industries, in electronics and electro-technique equipments, in energetically industries, etc. Optimizing this mechanism (the gears mechanism, we can improve the functionality of the transmissions with gears. At the gear mechanisms an important problem is the interference of the teeth. To avoid the interference between teeth, we must know the minimum number of teeth of the driving wheel, in function of the pressure angle (normal on the pitch circle, alpha0, in function of the tooth inclination angle (beta, and in function of the transmission ratio (i.

  13. Molecular Dynamics Simulations of Laser Powered Carbon Nanotube Gears

    Science.gov (United States)

    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.

  14. Physical and physiological aspects of gear efficiency in North Sea brown shrimp fisheries

    Science.gov (United States)

    Berghahn, R.; Wiese, K.; Lüdemann, K.

    1995-03-01

    In search of means to reduce the by-catch of juvenile flatfish in the shrimp fishery, vibrations and changes in current velocity caused by shrimp trawls were investigated in the field and in the laboratory. Buried as well as emerged shrimps ( Crangon crangon) exhibit tailflips 5 10 cm before being touched by the rollers of a shrimp gear approaching them at a speed of 0.5 m·sec-1, as was revealed by slow motion video recordings in aquaria under artificial light. Hence, the signal effective in triggering escape must be attenuated strongly with increasing distance. Sediment vibration, commonly assumed to be an important signal in triggering escape of shrimps, was found to decrease by a factor 100·m-1. Signals from the rollers of a commercial shrimp gear in operation (towing speed 1 m·sec-1) were directly recorded with an accelerometer. Their frequency ranged from 50 to 500 Hz and reached an acceleration of 40 m·sec-2 on soft bottom or up to 100 m·sec-2 on hard substrate. Accelerometers, which had been buried right at the surface of a tidal sand flat during low tide, produced only one sharp signal of 100 Hz with an acceleration of 24 m·sec-2, when a shrimp gear swept them on the submerged tidal flats. However, in aquaria short sinusoidal signals (Crangon accessible to the gear.

  15. GEAR WHEELS THE PROCESSED BY ELECTRICAL EROSION

    Directory of Open Access Journals (Sweden)

    MARCEL S.POPA

    2015-12-01

    Full Text Available For low tooth loads and low peripheral speeds between 0.3 and 2 m / s are chosen based alloys and steels, gray cast iron. In industry are preferable ferrous alloys: bronze, brass and aluminum alloys, and where speeds and demands are low gears are made of sheet steel or alloys. Wheel group required less include some hand-operated mechanisms, such as jacks, some trolls. These wheels are larger and they are made of alloy steel, semi-hard and sometimes gray cast iron FC250, FC300.

  16. Fishing gear-related injury in California marine wildlife.

    Science.gov (United States)

    Dau, Brynie Kaplan; Gilardi, Kirsten V K; Gulland, Frances M; Higgins, Ali; Holcomb, Jay B; Leger, Judy St; Ziccardi, Michael H

    2009-04-01

    We reviewed medical records from select wildlife rehabilitation facilities in California to determine the prevalence of injury in California Brown Pelicans (Pelecanus occidentalis), gulls (Larus spp.), and pinniped species (Zalophus californianus, Mirounga angustirostris, and Phoca vitulina) due to fishing gear entanglement and ingestion from 2001 to 2006. Of 9,668 Brown Pelican, gull, and pinniped cases described during the 6-yr study period (2001-06), 1,090 (11.3%) were fishing gear-related. Pelican injuries caused by fishing gear were most common in the Monterey Bay region, where 59.6% of the pelicans rescued in this area and admitted to a rehabilitation center were injured by fishing gear over the 6-yr period. The highest prevalence of fishing gear-related injury in gulls was documented in the Los Angeles/Orange County region (16.1%), whereas the highest prevalences in pinnipeds were seen in the San Diego region (3.7%). Despite these higher prevalences of gull and pinniped fishing gear-related injuries in these specific regions, there was no statistical significance in these trends. Juvenile gulls and pinnipeds were more commonly injured by fishing gear than adults (gulls: P = 0.03, odds ratio = 1.29; pinnipeds: P = 0.01, odds ratio = 2.07). Male pinnipeds were twice as likely to be injured by fishing gear as females (P gear-related injury cases that were successfully rehabilitated and released (percentage of cases successfully rehabilitated to the point of release out of the total number of fishing gear-related injury cases) was high in all three species groups (pelicans: 63%; gulls: 54%; pinnipeds: 70%). Fishing gear-related injuries in Brown Pelicans and gulls were highest in the fall, but there was only a significant difference between seasons for fishing gear-related injuries in pelicans. Fishing gear-related injuries in pinnipeds most commonly occurred in summer; however, a statistical difference was not detected between seasons for pinnipeds. Derelict

  17. Hybrid foundry patterns of bevel gears

    Directory of Open Access Journals (Sweden)

    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.

  18. Composite skid landing gear design investigation

    Science.gov (United States)

    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. Demonstrations of bio-inspired perching landing gear for UAVs

    Science.gov (United States)

    Tieu, Mindy; Michael, Duncan M.; Pflueger, Jeffery B.; Sethi, Manik S.; Shimazu, Kelli N.; Anthony, Tatiana M.; Lee, Christopher L.

    2016-04-01

    Results are presented which demonstrate the feasibility and performance of two concepts of biologically-inspired landing-gear systems that enable bird-sized, unmanned aerial vehicles (UAV's) to land, perch, and take-off from branchlike structures and/or ledges. The first concept follows the anatomy of birds that can grasp ahold of a branch and perch as tendons in their legs are tensioned. This design involves a gravity-activated, cable-driven, underactuated, graspingfoot mechanism. As the UAV lands, its weight collapses a four-bar linkage pulling a cable which curls two opposing, multi-segmented feet to grasp the landing target. Each foot is a single, compliant mechanism fabricated by simultaneouly 3D-printing a flexible thermo-plastic and a stiffer ABS plastic. The design is optimized to grasp structures over a range of shapes and sizes. Quasi-static and flight tests of this landing gear affixed to RC rotorcraft (24 cm to 550 cm in diameter) demonstrate that the aircraft can land, perch, and take-off from a tree branch, rectangular wood board, PVC pipe, metal hand rail, chair armrest, and in addition, a stone wall ledge. Stability tests show that perching is maintained under base and wind disturbances. The second design concept, inspired by roosting bats, is a two-material, 3D-printed hooking mechanism that enables the UAV to stably suspend itself from a wire or small-diameter branch. The design balances structural stiffness for support and flexibility for the perching process. A flight-test demonstrates the attaching and dis-engaging of a small, RC quadcopter from a suspended line.

  20. Contact stress analysis of involute spur gear by Finite Element ...

    African Journals Online (AJOL)

    In this paper the contact stress in rolling-sliding contact of involute spur gear and the effect of coefficient of friction was analyzed. To achieve this, first, three dimensional involute spur gear pairs were developed in Solid works 2012 Premium and the 3D model was exported to ANSYS workbench 14.5. Next, the analysis was ...

  1. Nonlinear Vibroimpact Characteristics of a Planetary Gear Transmission System

    Directory of Open Access Journals (Sweden)

    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.

  2. 50 CFR 300.130 - Vessel and gear restrictions.

    Science.gov (United States)

    2010-10-01

    ... 50 Wildlife and Fisheries 7 2010-10-01 2010-10-01 false Vessel and gear restrictions. 300.130... gear restrictions. (a) Factory vessels. Factory vessels are prohibited from operating in treaty waters... top of the trap that, when removed, will leave an opening no smaller than the throat or entrance of...

  3. Involute Spur Gear Template Development by Parametric Technique ...

    African Journals Online (AJOL)

    Nekky Umera

    An International Multi-Disciplinary Journal, Ethiopia. Vol. 3 (2), January, 2009. ISSN 1994-9057 (Print). ISSN 2070-0083 (Online). Involute Spur Gear Template Development by ... The third method and the most accurate system is the graphic ..... a three-dimensional part directly from a parametric solid modeled gear file.

  4. Modelling of acoustic emission generated in involute spur gear pair

    Science.gov (United States)

    Sharma, Ram Bihari; Parey, Anand; Tandon, Naresh

    2017-04-01

    Acoustic emission (AE) is an important technique for the condition monitoring and diagnostics of various mechanical system components like gear, bearing, macahine tool etc. Several researchers have found experimentally that gear operating parameters such as speed, load, specific film thickness, temperature etc. influence the energy of AE generated during meshing of the gears. But there is lack of mathematical model to comprehend the actual physical mechanism in the gear for the same. In this study, a theoretical model has been developed to establish a rapport between gear operating parameters and energy of AE on the bases of asperity contact and friction between involute surfaces of gear using Hertzian contact approach, statistical concepts, and varying sliding velocity of gear tooth mechanism. The effects of load sharing, lubrication, and dynamic load condition during the gear mesh cycle are also considered in the developed model. An experimental study has been performed for validation of developed theoretical model. A satisfactory validation has been perceived between the AE rms (root mean square) predicted by the developed theoretical model and obtained experimental results.

  5. High-speed T-38A landing gear extension loads

    Science.gov (United States)

    Schmitt, A. L.

    1980-01-01

    Testing of T-38A landing gear extension at high speed and high altitude is described. The mechanisms are shown together with peak hydraulic pressure data during landing gear deployment with active and inactive strut door flaps. Results of strain gage measurements of stress on various structural members are included.

  6. Fishing gear selectivity for Lates niloticus L., Oreochromis niloticus L ...

    African Journals Online (AJOL)

    Catch effort data on which fisheries management regulations are sometimes based are not available for most lakes in Uganda. However, failure to regulate fishing gears and methods has been a major cause of collapse of fisheries in the country. Fisheries hiwe been damaged by destructive and non-selective fishing gears ...

  7. 49 CFR 229.57 - Foundation brake gear.

    Science.gov (United States)

    2010-10-01

    ... 49 Transportation 4 2010-10-01 2010-10-01 false Foundation brake gear. 229.57 Section 229.57 Transportation Other Regulations Relating to Transportation (Continued) FEDERAL RAILROAD ADMINISTRATION... Foundation brake gear. A lever, rod, brake beam, hanger, or pin may not be worn through more than 30 percent...

  8. Design of Gear Defect Detection System Based on Machine Vision

    Science.gov (United States)

    Wang, Yu; Wu, Zhiheng; Duan, Xianyun; Tong, Jigang; Li, Ping; Chen, min; Lin, Qinglin

    2018-01-01

    In order to solve such problems as low efficiency, low quality and instability of gear surface defect detection, we designed a detection system based on machine vision, sensor coupling. By multisensory coupling, and then CCD camera image collection of gear products, using VS2010 to cooperate with Halcon library for a series of analysis and processing of images. At last, the results are fed back to the control end, and the rejected device is removed to the collecting box. The system has successfully identified defective gear. The test results show that this system can identify and eliminate the defects gear quickly and efficiently. It has reached the requirement of gear product defect detection line automation and has a certain application value.

  9. Investigations of Shuttle Main Landing Gear Door Environmental Seals

    Science.gov (United States)

    Finkbeiner, Joshua; Dunlap, Pat; Steinetz, Bruce; DeMango, Jeff; Newswander, Daniel

    2005-01-01

    The environmental seals for the main landing gear doors of the Shuttle Orbiters were raised by the Columbia Accident Investigation Board as a potential safety concern. Inspections of seals installed on the Shuttle Discovery revealed that they were permanently deformed and no longer met certified seal compression requirements. Replacement of the seals led to the inability to fully close the main landing gear doors. Johnson Space Center requested that Glenn Research Center conduct tests on the main landing gear door environmental seals to assist in installing the seals in a manner to allow the main landing gear doors to fully close. Further testing was conducted to fill out the seal performance database. Results from the testing indicated that the method of bonding the seals was important in reducing seal loads on the main landing gear doors. Also, the replacement seals installed in Shuttle Discovery were found to have leakage performance sufficient to meet the certification requirements.

  10. GEAR: A database of Genomic Elements Associated with drug Resistance.

    Science.gov (United States)

    Wang, Yin-Ying; Chen, Wei-Hua; Xiao, Pei-Pei; Xie, Wen-Bin; Luo, Qibin; Bork, Peer; Zhao, Xing-Ming

    2017-03-15

    Drug resistance is becoming a serious problem that leads to the failure of standard treatments, which is generally developed because of genetic mutations of certain molecules. Here, we present GEAR (A database of Genomic Elements Associated with drug Resistance) that aims to provide comprehensive information about genomic elements (including genes, single-nucleotide polymorphisms and microRNAs) that are responsible for drug resistance. Right now, GEAR contains 1631 associations between 201 human drugs and 758 genes, 106 associations between 29 human drugs and 66 miRNAs, and 44 associations between 17 human drugs and 22 SNPs. These relationships are firstly extracted from primary literature with text mining and then manually curated. The drug resistome deposited in GEAR provides insights into the genetic factors underlying drug resistance. In addition, new indications and potential drug combinations can be identified based on the resistome. The GEAR database can be freely accessed through http://gear.comp-sysbio.org.

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

    DEFF Research Database (Denmark)

    Pedersen, Niels Leergaard

    2015-01-01

    The strength of a gear is typically defined relative to durability (pitting) and load capacity (tooth-breakage). Tooth-breakage is controlled by the root shape and this gear part can be designed because there is no contact between gear pairs here. The shape of gears is generally defined by differ......The strength of a gear is typically defined relative to durability (pitting) and load capacity (tooth-breakage). Tooth-breakage is controlled by the root shape and this gear part can be designed because there is no contact between gear pairs here. The shape of gears is generally defined...

  12. Dynamic Research of the Flexible Wheel of a Double Harmonic Gear Transmission

    Directory of Open Access Journals (Sweden)

    Draghita Ianici

    2015-07-01

    Full Text Available The paper presents the results of a dynamic research of the flexible wheel of the double harmonic gear transmission, by determining the state of strain and stress of its wall, in cases the wheel is deformed by a mechanical waves generator with: two rolls, two eccentric discs and cam. The dynamic research involves modelling and the numerical simulation of flexible wheel, by using the finite element method, with the help of SolidWorks Simulation program in elastic range.

  13. Assessment of potential energy savings following the replacement of gear-motor-driven systems by frequency-converter-fed direct drives; Energiesparpotential bei Ersatz von Getriebemotoren durch FU-Antriebe. Potentialanalyse

    Energy Technology Data Exchange (ETDEWEB)

    Tanner, R.; Riesen, H. J.

    2007-03-15

    This project deals with the energy saving potential that can be achieved by replacing gear motor driven systems by frequency converter fed direct drives. Estimates have shown that due to the high percentage of gear motor installations, which amounts to approximately 10% of all motor driven systems, a significant amount of energy could be saved. However, several barriers impose major restrictions to the broad application of such actions: With the exception of worm gears that reach about 20% of all gear drives, todays' gears already offer a high efficiency of 97-98%. Gear motors are often included in OEM integrated solutions. Many processes require complex adaptations that can complicate replacements or make it even impractical. For low speed or high torque requirements, gear motors may have a dominant advantage concerning the compactness. Our investigations have shown, that in spite of such barriers the replacement of gear motors by direct motors can sum up to a significant amount of energy savings in many cases. Looking at the worm gear systems and the restricted speed and torque ranges that are covered by the direct drives from several suppliers we assume a total saving potential of about 78 GWh per year for Switzerland. (author)

  14. Generation of gear tooth surfaces by application of CNC machines

    Science.gov (United States)

    Litvin, F. L.; Chen, N. X.

    1994-01-01

    This study will demonstrate the importance of application of computer numerically controlled (CNC) machines in generation of gear tooth surfaces with new topology. This topology decreases gear vibration and will extend the gear capacity and service life. A preliminary investigation by a tooth contact analysis (TCA) program has shown that gear tooth surfaces in line contact (for instance, involute helical gears with parallel axes, worm gear drives with cylindrical worms, etc.) are very sensitive to angular errors of misalignment that cause edge contact and an unfavorable shape of transmission errors and vibration. The new topology of gear tooth surfaces is based on the localization of bearing contact, and the synthesis of a predesigned parabolic function of transmission errors that is able to absorb a piecewise linear function of transmission errors caused by gear misalignment. The report will describe the following topics: description of kinematics of CNC machines with six degrees of freedom that can be applied for generation of gear tooth surfaces with new topology. A new method for grinding of gear tooth surfaces by a cone surface or surface of revolution based on application of CNC machines is described. This method provides an optimal approximation of the ground surface to the given one. This method is especially beneficial when undeveloped ruled surfaces are to be ground. Execution of motions of the CNC machine is also described. The solution to this problem can be applied as well for the transfer of machine tool settings from a conventional generator to the CNC machine. The developed theory required the derivation of a modified equation of meshing based on application of the concept of space curves, space curves represented on surfaces, geodesic curvature, surface torsion, etc. Condensed information on these topics of differential geometry is provided as well.

  15. Dual lead-crowning for helical gears with anti-twist tooth flanks on the internal gear honing machine

    Science.gov (United States)

    Tran, Van-Quyet; Wu, Yu-Ren

    2017-12-01

    For some specific purposes, a helical gear with wide face-width is applied for meshing with two other gears simultaneously, such as the idle pinions in the vehicle differential. However, due to the fact of gear deformation, the tooth edge contact and stress concentration might occur. Single lead-crowning is no more suitable for such a case to get the appropriate position of contact pattern and improve the load distribution on tooth surfaces. Therefore, a novel *Email: method is proposed in this paper to achieve the wide-face-width helical gears with the dual lead-crowned and the anti-twisted tooth surfaces by controlling the swivel angle and the rotation angle of the honing wheel respectively on an internal gear honing machine. Numerical examples are practiced to illustrate and verified the merits of the proposed method.

  16. Acoustical analysis of gear housing vibration

    Science.gov (United States)

    Seybert, A. F.; Wu, T. W.; Wu, X. F.; Oswald, Fred B.

    1991-01-01

    The modal and acoustical analysis of the NASA gear-noise rig is described. Experimental modal analysis techniques were used to determine the modes of vibration of the transmission housing. The resulting modal data were then used in a boundary element method (BEM) analysis to calculate the sound pressure and sound intensity on the surface of the housing as well as the radiation efficiency of each mode. The radiation efficiencies of the transmission housing modes are compared with theoretical results for finite, baffled plates. A method that uses the measured mode shapes and the BEM to predict the effect of simple structural changes on the sound radiation efficiency of the modes of vibration is also described.

  17. Investigating Vibration Properties of a Planetary Gear Set with a Cracked Tooth in a Planet Gear

    Science.gov (United States)

    2014-12-23

    sidebands appear at mfm±nfplanet± kfc or mfm±nfplanet±kfp, where m, n and k are all integers; fp represents rotation frequency of the planet gear and...region from 43 fm to 45 fm. Sidebands are not symmetric and sizable sidebands located at mfm±nfplanet± kfc or mfm±nfplanet±kfp, where m, n and k are

  18. Effect of a single-session meditation training to reduce stress and improve quality of life among health care professionals: a "dose-ranging" feasibility study.

    Science.gov (United States)

    Prasad, Kavita; Wahner-Roedler, Dietlind L; Cha, Stephen S; Sood, Amit

    2011-01-01

    The primary aim of the study was to assess the feasibility of incorporating a single-session meditation-training program into the daily activities of healthy employees of a tertiary-care academic medical center. The study also assessed the most preferred duration of meditation and the effect of the meditation program on perceived stress, anxiety, and overall quality of life (QOL). Seventeen healthy clinic employees were recruited for this study. After an initial group instruction session covering basic information about meditation, Paced Breathing Meditation (PBM) was taught to the participants. Participants were instructed to self-practice meditation with the help of a DVD daily for a total of 4 weeks. The DVD had three different programs of 5, 15, and 30 minutes with a menu option to choose one of the programs. (1) Patient diary, (2) Perceived Stress Scale (PSS), (3) Linear Analogue Self-Assessment (LASA), (4) Smith Anxiety Scale (SAS). Primary outcome measures were compared using the paired t-test. All participants were female; median age was 48 years (range 33-60 y). The 5-minute meditation session was practiced by 14 participants a total of 137 times during the 4-week trial period, the 15-minute session by 16 participants a total of 223 times, and the 30-minute session by 13 participants 71 times. The median number of days practiced was 25 (range 10-28 d); the average total time practiced was 394 minutes (range 55-850 min). After 4 weeks of practice, the scores of the following instruments improved significantly from baseline: PSS (P stress, anxiety, and QOL.

  19. Two dimensional model of a permanent magnet spur gear

    DEFF Research Database (Denmark)

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

    2005-01-01

    This paper presents calculation and measurement results of a high-performance permanent-magnetic gear. The analyzed permanent-magnetic gear has a gear ratio of 5.5 and is able to deliver 27 N/spl middot/m. The analysis has shown that special attention needs to be paid to the system where the gear...... is to be installed because of a low natural torsion spring constant. The analyzed gear was also constructed in practice in order to validate the analysis and predict the efficiency. The measured torque from the magnetic gear was only 16 N/spl middot/m reduced by the large end-effects. A systematic 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 losses...

  20. A Study on the Dynamic Behaviour of Lightweight Gears

    Directory of Open Access Journals (Sweden)

    Shadi Shweiki

    2017-01-01

    Full Text Available This paper investigates the dynamic effects of mass reduction on a pair of spur gears. A one-Degree-of-Freedom (DOF model of a mechanical oscillator with clearance-type nonlinearity and linear viscous damping is used to perform the investigations. One-dimensional (1D gear pair models aim at studying the torsional gear vibrations around the rotational axes and can be used to simulate either gear whine or gear rattle phenomena. High computational efficiency is reached by using a spring-damper element with variable stiffness to model the gear meshing process. The angle-dependent mesh stiffness function is computed in a preparation phase through detailed Finite Element (FE simulations and then stored in a lookup table, which is then interpolated during the dynamic simulation allowing for high computational efficiency. Nonlinear contact effects and influence of material discontinuities due to lightweighting are taken into account by FE simulations with high level of detail. Finally, the influence of gear body topology is investigated through a sensitivity analysis, in which analytical functions are defined to describe the time-varying mesh stiffness.

  1. Hybrid Gear Performance Under Loss-of-Lubrication Conditions

    Science.gov (United States)

    Laberge, Kelsen E.; Berkebile, Stephen P.; Handschuh, Robert F.; Roberts, Gary D.

    2017-01-01

    Hybrid composite gear technology is being investigated to increase power density in rotorcraft drive systems. These gears differ from conventional steel gears in that the structural web material is replaced with a lightweight carbon fiber composite. Past studies have focused on performance of this technology under normal operating conditions, however, for this technology to be viable it must also withstand adverse conditions. The study presented here evaluates the performance of hybrid gears under loss-of-lubrication conditions in NASA Glenn Research Centers Contact Fatigue Test Facility. Two experiments are presented using small-scale 3.5 inch (8.9 cm) pitch diameter hybrid gears and compared to a baseline steel gear pair. Results of these tests show that there are limitations to the use of a hexagonal interlock pattern between the steel and composite. There is also evidence that the presence of polymer in the gear during an oil out event has a potential to increase time to failure. Further studies are planned to expand on these initial findings.

  2. Dynamics of Multistage Gear Transmission with Effects of Gearbox Vibrations

    Science.gov (United States)

    Choy, F. K.; Tu, Y. K.; Zakrajsek, J. J.; Townsend, Dennis P.

    1990-01-01

    A comprehensive approach is presented in analyzing the dynamic behavior of multistage gear transmission systems with the effects of gearbox induced vibrations and mass imbalances of the rotor. The modal method, with undamped frequencies and planar mode shapes, is used to reduce the degrees of freedom of the gear system for time-transient dynamic analysis. Both the lateral and torsional vibration modes of each rotor-bearing-gear stage as well as the interstage vibrational characteristics are coupled together through localized gear mesh tooth interactions. In addition, gearbox vibrations are also coupled to the rotor-bearing-gear system dynamics through bearing support forces between the rotor and the gearbox. Transient and steady state dynamics of lateral and torsional vibrations of the geared system are examined in both time and frequency domains to develop interpretations of the overall modal dynamic characteristics under various operating conditions. A typical three-stage geared system is used as an example. Effects of mass imbalance and gearbox vibrations on the system dynamic behavior are presented in terms of modal excitation functions for both lateral and torsional vibrations. Operational characteristics and conclusions are drawn from the results presented.

  3. Modal analysis of multistage gear systems coupled with gearbox vibrations

    Science.gov (United States)

    Choy, F. K.; Ruan, Y. F.; Tu, Y. K.; Zakrajsek, J. J.; Townsend, D. P.

    1991-01-01

    An analytical procedure to simulate vibrations in gear transmission systems is presented. This procedure couples the dynamics of the rotor-bearing gear system with the vibration in the gear box structure. The model synthesis method is used in solving the overall dynamics of the system, and a variable time-stepping integration scheme is used in evaluating the global transient vibration of the system. Locally each gear stage is modeled as a multimass rotor-bearing system using a discrete model. The modal characteristics are calculated using the matrix-transfer technique. The gearbox structure is represented by a finite element models, and modal parameters are solved by using NASTRAN. The rotor-gear stages are coupled through nonlinear compliance in the gear mesh while the gearbox structure is coupled through the bearing supports of the rotor system. Transient and steady state vibrations of the coupled system are examined in both time and frequency domains. A typical three-geared system is used as an example for demonstration of the developed procedure.

  4. Evaluation of Gear Condition Indicator Performance on Rotorcraft Fleet

    Science.gov (United States)

    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.

  5. Technology Innovation of Power Transmission Gearing in Aviation

    Science.gov (United States)

    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.

  6. 50 CFR 697.23 - Restricted gear areas.

    Science.gov (United States)

    2010-10-01

    ... Measures § 697.23 Restricted gear areas. (a) Resolution of lobster gear conflicts with fisheries managed.... 70°16.1′ W. to 181 39°59.3′ N. 70°14.0′ W. Offshore Boundary Point to Latitude Longitude 69 40°07.9...°59.7′ N. 70°13.05′ W. 181 39°59.3′ N. 70°14.0′ W. to 119 40°02.75′ N. 70°16.1′ W. (c) Restricted Gear...

  7. Engagement of Metal Debris into a Gear Mesh

    Science.gov (United States)

    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. Life and reliability modeling of bevel gear reductions

    Science.gov (United States)

    Savage, M.; Brikmanis, C. K.; Lewicki, D. G.; Coy, J. J.

    1985-01-01

    A reliability model is presented for bevel gear reductions with either a single input pinion or dual input pinions of equal size. The dual pinions may or may not have the same power applied for the analysis. The gears may be straddle mounted or supported in a bearing quill. The reliability model is based on the Weibull distribution. The reduction's basic dynamic capacity is defined as the output torque which may be applied for one million output rotations of the bevel gear with a 90 percent probability of reduction survival.

  9. Stress Analysis of Gear Meshing Impact Based on SPH Method

    Directory of Open Access Journals (Sweden)

    Rahmatjan Imin

    2014-01-01

    Full Text Available Based on the kinetic equations of the gear mesh impact, SPH discrete equations were established. Numerical simulation was carried out on the meshing impact process of the gear, and stress and strain of each discrete point were obtained. After data processing, stress propagation was calculated, which shows stress distribution on tooth-profile surface. It is concluded that the stress concentrate mainly occurs in the pitch circle. The paper provides an effective new numerical simulation algorithm to gear mechanical properties analysis.

  10. Influence of various base oils on friction and power loss in gears; Einfluss verschiedener Grundoele auf Reibung und Verlustleistung in Zahnradgetrieben

    Energy Technology Data Exchange (ETDEWEB)

    Doleschel, A.; Michaelis, K.; Hoehn, B.R.

    2001-03-01

    The frictional behaviour of synthetic lubricants was systematically investigated in a twin disc test rig and a back-to-back gear test rig. For 22 lubricants (mineral oil, polyalfaolefin (PAO), polyglycol (PG), ester and mixtures) the coefficient of friction was measured in the twin disc test rig, dependant on pressure, oil temperature, rolling and sliding velocity. In the gear test rig pressure and velocity was varied for 9 lubricants. The mineral oil shows an estimated coefficient of friction of about {mu} >> 0.045, the synthetic lubricants have a lower coefficient of friction. In the twin disc test rig the lowest coefficient of friction with PG as low as 20% of the coefficient of mineral oil was measured, depending on the mixture of EO:PO. In the gear test rig such low coefficients of friction were not measured, but still values of 60% compared to mineral oil were obtained. Esters show in the twin disc test rig a coefficient of friction in the range of 30% to 100% of the coefficient of friction of mineral oil, in the gear test rig in the range of 60% to 100%. From these investigations a calculation method for the coefficient of friction in disc and gear contacts was derived. With these equations the power loss and efficiency of transmissions in practice, lubricated with synthetic gear oils can be evaluated. (orig.)

  11. PM2.5 Gravimetric Lab Training (2016 NAAMC)

    Science.gov (United States)

    This training focused on understanding/applying the PM2.5 FRM in 40 CFR part 50, Appendix L and the updated QA Guidance Document 2.12. it was geared primarily for monitoring and QA managers and staff.

  12. Evaluation of a peat moss plus soybean oil (PMSO) technology for reducing explosive residue transport to groundwater at military training ranges under field conditions.

    Science.gov (United States)

    Fuller, Mark E; Schaefer, Charles E; Steffan, Robert J

    2009-11-01

    An evaluation of peat moss plus crude soybean oil (PMSO) for mitigation of explosive contamination of soil at military facilities was performed using large soil lysimeters under field conditions. Actual range soils were used, and two PMSO preparations with different ratios of peat moss:soybean oil (1:1, PO1; 1:2, PO2) were compared to a control lysimeter that received no PMSO. PMSO was applied as a 10 cm layer on top of the soil, and Composition B detonation residues from a 55-mm mortar round were applied at the surface of each of the lysimeters. Dissolution of the residues occurred during natural precipitation events over the course of 18 months. Hexahydro-1,3,5-trinitro-1,3,5-triazine (RDX) emanating from the Composition B residues were significantly reduced by the PO2 PMSO material compared to the untreated control. Soil pore water RDX concentrations and RDX fluxes were reduced over 100-fold compared to the control plots at comparable depths. Residual RDX in the soil profile was also significantly lower in the PMSO treated plots. PO1 PMSO resulted in lower reductions in RDX transport than the PO2 PMSO. The transport of the RDX breakdown product hexahydro-1-nitroso-3,5-dinitro-1,3,5-triazine (MNX) was also greatly reduced by the PMSO materials. Results were in general agreement with a previously developed fate and transport model describing PMSO effectiveness. These results demonstrate the potential effectiveness of the inexpensive and environmentally benign PMSO technology for reducing the subsurface loading of explosives at training ranges and other military facilities.

  13. 14 CFR 23.729 - Landing gear extension and retraction system.

    Science.gov (United States)

    2010-01-01

    ... use of hydraulic pressure) to keep the landing gear extended. (c) Emergency operation. For a landplane... 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...

  14. 46 CFR 97.37-33 - Instructions for changing steering gear.

    Science.gov (United States)

    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 be...

  15. 46 CFR 58.25-10 - Main and auxiliary steering gear.

    Science.gov (United States)

    2010-10-01

    ... 46 Shipping 2 2010-10-01 2010-10-01 false Main and auxiliary steering gear. 58.25-10 Section 58.25... AUXILIARY MACHINERY AND RELATED SYSTEMS Steering Gear § 58.25-10 Main and auxiliary steering gear. (a) Power-operated main and auxiliary steering gear must be separate systems that are independent throughout their...

  16. 50 CFR Table 19 to Part 679 - Seabird Avoidance Gear Codes

    Science.gov (United States)

    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 prevent...

  17. Equi-Depth Tooth Hypoid Gear Using Formate Gear Cutting Method : 2nd Report, Cutting Conditions and Tooth Bearing Pattern

    OpenAIRE

    伊藤, 紀男; 野村, 和弘

    1995-01-01

    In general, a hypoid gear and a spiral bevel gear for cars are made up of a formate gear and a generated pinion. The tooth shape is tapered tooth. Much practice is required to obtain excellent tooth bearing of the tapered tooth. If we convert a tapered tooth to an equi-depth tooth, it is thought that we could easily obtain practical tooth bearing. To date, however, there is no paper that theoretically analyzes tooth bearing of the equi-depth tooth and actually demonstrates it. Therefore the t...

  18. Design and analysis of composite spur gears using finite element method

    Science.gov (United States)

    Rajeshkumar, S.; Manoharan, R.

    2017-11-01

    In this study, the parametric design and contact analysis of composite spur gears are investigated numerically. Composite gear provides an adequate strength to weight ratio, more hardness, durability and low maintenance cost. It is emerging better alternatives for replacing metallic gears. The finite element model of spur gear is developed with the assistance of the Ansys software. In this study each design factor such has stress distributions, strain and deformation are considered to compare composite gear with steel and polymer gears. An APDL gear model has been developed for the design evaluation and comparison study.

  19. Plasma Fairings for Quieting Aircraft Landing Gear Noise Project

    Data.gov (United States)

    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...

  20. Characteristics study of the gears by the CAD/CAE

    Science.gov (United States)

    Wang, P. Y.; Chang, S. L.; Lee, B. Y.; Nguyen, D. H.; Cao, C. W.

    2017-09-01

    Gears are the most important transmission component in machines. The rapid development of the machines in industry requires a shorter time of the analysis process. In traditional, the gears are analyzed by setting up the complete mathematical model firstly, considering the profile of cutter and coordinate systems relationship between the machine and the cutter. It is a really complex and time-consuming process. Recently, the CAD/CAE software is well developed and useful in the mechanical design. In this paper, the Autodesk Inventor® software is introduced to model the spherical gears firstly, and then the models can also be transferred into ANSYS Workbench for the finite element analysis. The proposed process in this paper is helpful to the engineers to speed up the analyzing process of gears in the design stage.

  1. 3D MODELLING WITH THE SAMSUNG GEAR 360

    National Research Council Canada - National Science Library

    L. Barazzetti; M. Previtali; F. Roncoroni

    2017-01-01

    .... The aim of this work is to test the metric accuracy and the level of detail achievable with the Samsung Gear 360 coupled with digital modelling techniques based on photogrammetry/computer vision algorithms...

  2. Analysis of vibration characteristic for helical gear under hydrodynamic conditions

    Directory of Open Access Journals (Sweden)

    Fuhao Liu

    2017-01-01

    Full Text Available Based on the elasto-hydrodynamic lubrication theory, a 2-degree-of-freedom nonlinear dynamic model of helical gears with double-sided film is proposed, in which the minimum film thickness behaves as a function of load parameters, lubricant parameters, and the geometry of the contact. Then, the comparison of the hysteresis loops in different gear models shows the soundness of the presented model. Using numerical method, the time evolution of lubricant normal force, minimum film thickness, and lubricant stiffness is obtained in order to demonstrate the influence of the driving torque and pinion’s velocity. The results obtained in this article can contribute to the root cause for the gear vibration and show that the hydrodynamic flank friction has almost no influence on the gear system.

  3. Vibration Signature Analysis of a Faulted Gear Transmission System

    Science.gov (United States)

    Choy, F. K.; Huang, S.; Zakrajsek, J. J.; Handschuh, R. F.; Townsend, D. P.

    1996-01-01

    A comprehensive procedure in predicting faults in gear transmission systems under normal operating conditions is presented. Experimental data were obtained from a spiral bevel gear fatigue test rig at NASA/Lewis. Time-synchronous-averaged vibration data were recorded throughout the test as the fault progressed from a small single pit to severe pitting over several teeth, and finally tooth fracture. A numerical procedure based on the Wigner-Ville distribution was used to examine the time-averaged vibration data. Results from the Wigner-Ville procedure are compared to results from a variety of signal analysis techniques that include time-domain analysis methods and frequency analysis methods. Using photographs of the gear tooth at various stages of damage, the limitations and accuracy of the various techniques are compared and discussed. Conclusions are drawn from the comparison of the different approaches as well as the applicability of the Wigner-Ville method in predicting gear faults.

  4. Computer simulation of gear cutting and strength analysis with ...

    African Journals Online (AJOL)

    helical gear in mechanical power transmissions. This is because of its advantages in standardization, machining, high efficiency and adaptability to load and center distance. For mechanical power transmission, involving high speed a maximum, ...

  5. The dogfish scourge: protecting fishing gear from shark attack

    National Research Council Canada - National Science Library

    Hurley, G.V; Stone, H.H; Lemon, D

    1987-01-01

    .... Effective shark repellents, on or near gear, must overcome these attractive stimuli and, at the same time, not discourage commercially desirable species, not be toxic to fish or humans, and be affordable...

  6. Close-up of LSRA Shuttle main gear

    Science.gov (United States)

    1993-01-01

    A space shuttle landing gear system is clearly seen between the two main landing gear components on this NASA CV-990, modified as a Landing Systems Research Aircraft. The space shuttle landing gear test unit, operated by a high-pressure hydraulic system, allowed engineers to assess and document the performance of space shuttle main and nose landing gear systems, tires and wheel assemblies, plus braking and nose wheel steering performance. The series of 155 test missions for the space shuttle program, conducted at NASA's Dryden Flight Research Center, Edwards, California, provided extensive data about the life and endurance of the shuttle tire systems and helped raise the shuttle crosswind landing limits at Kennedy.

  7. Enhanced Prediction of Gear Tooth Surface Fatigue Life Project

    Data.gov (United States)

    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...

  8. Environmental Impact Statement, Establishment of the Gandy Range Extension and Adjacent Restricted Airspace as an Area for Supersonic Flight Training, Hill AFB, Utah

    Science.gov (United States)

    1985-10-03

    training. The authority to exceed the speed of sound is required to remove artificial restrictions on training. The piiot needs to train as he will...maintain subsonic speeds would be an artificial barrier that would not exist in actual ’wartime" situations and pilots may actually develop bad habits...ould be the human egg, the unborn child within the mother’s womb , is affected by sonic boom which would be - children in schools relating to their

  9. Reduction of contact stresses using involute gears with asymmetric teeth

    Directory of Open Access Journals (Sweden)

    Jarmila VOJTKOVÁ

    2015-12-01

    Full Text Available Asymmetrical involute gears have a different value of the operating pressure angle for right and left side of the gear. These teeth are suitable for one direction of rotation. Such teeth enable to change the length of the generating line. They enable to improve the value of reduced radii of curvature. Asymmetrical teeth allow reducing the values of Hertz's pressures, especially on the root of the teeth. Hertz pressures are directly related to the asymmetry.

  10. Darwin-industrien i højt gear

    DEFF Research Database (Denmark)

    Kjærgaard, Peter C.

    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...

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

    OpenAIRE

    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...

  12. VTVL concept optimisation of the landing gear

    Directory of Open Access Journals (Sweden)

    Camelia Elena MUNTEANU

    2017-03-01

    Full Text Available Vertical takeoff, vertical landing (VTVL is a subject of international interest at the moment thanks to the successful recovery of the Blue Origin vehicle. Aggressive weight targets with a short development time in the aerospace and space industry clearly need an integration of advanced computer aided structural optimization methods. Topological optimization is used from the concept phase of a design process development in order to obtain a fundamental design approach. The aim of the article is to determine the principal directions for distribution of the material for a VTVL landing gear within the specified volume in order to obtain the initial design approach. To achieve the maximum performance within the studied component, the result is then refined from a manufacturability point of view. The use of such methods notably reduces the development iterations between the design and stress departments. Thus, the overall time is reduced which translates into a lower overall cost and shorter time development from the concept to the final product.

  13. High-speed gears for gas turbine drive

    Energy Technology Data Exchange (ETDEWEB)

    Kane, J.

    1995-06-01

    Recently, Lufkin Industries, Power Transmission Div., full-load tested a high-speed gear designed to couple a 50 Hz electric power generator to a GE LM6000 gas turbine for a power generation project in Australia. The gear is rated 52.2 MW to match the output of the LM6000 gas turbine believed to be one of the largest gear testing operations for this type and size of gear. Each gear drive manufactured by Lufkin is full-speed tested to verify its performance. Tests performed on high-speed units duplicate field conditions, as closely as possible, in order to verify critical speed analysis results and new bearing designs, if used. Lufkin also tests design techniques used in the development of new products. The finite element analysis performed to predict housing deflection in the thrust bearing area of a new extruder driveline was verified by testing of a prototype unit housing. Recently, housing structure stiffness and natural frequencies were predicted and verified on the test stand for some 50 MW vertically offset gear units. A complete data acquisition system is used to gather data from bearing, inlet and drain temperature monitoring points. The temperature monitoring system will accommodate type T,K,J, and E thermocouples and platinum and nickel RTDs.

  14. Internally geared screw machines with ported end plates

    Science.gov (United States)

    Read, M. G.; Smith, I. K.; Stosic, N.

    2017-08-01

    It is possible to design cylindrical helical gearing profiles such that an externally lobed inner gear rotates inside an internally lobed outer gear while maintaining continuous lines of contact between the gears. The continuous contact between the inner and outer rotors (analogous to the main and gate rotors in a conventional screw machine) creates a series of separate working chambers. In this type of machine the rotors have parallel axes of rotation, and if both rotors are free to rotate about their own axes, these axes can be fixed in space. The use of ported end plates is proposed to control the period during which fluid is allowed to enter or leave the working chambers of the internally geared screw machine. As with conventional screw machines, these internally geared rotors can then be used to achieve compression or expansion of a trapped mass of fluid, and the machine geometry can be designed in order to optimise performance for particular applications. This paper describes the geometrical analysis of some simple rotor profiles and explores the effect on rotor torques for particular applications of this novel screw configuration.

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

    Directory of Open Access Journals (Sweden)

    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. Study on Warm Forging Prosess of 45 Steel Asymmetric Gear

    Science.gov (United States)

    Qi, Yushi; Du, Zhiming; Sun, Hongsheng; Chen, Lihua; Wang, Changshun

    2017-09-01

    Asymmetric gear has complex structure, so using plastic forming technology to process the gear has problems of large forming load, short die life, bad tooth filling, and so on. To solve these problems, this paper presents a radial warm extrusion process of asymmetric gear to reduce the forming load and improve the filling in the toothed corner portion. Using the new mold and No. 45 steel to conducting forming experiments under the optimal forming parameters: billet temperature is 800°C, mold temperature is 250°C, the forming speed is 30mm/s, and the friction coefficient is 0.15, we can obtain the complete asymmetric gear with better surface and tooth filling. Asymmetric gears’ microstructure analysis and mechanical testing showed that the small grain evenly distributed in the region near the addendum circle with high strength; the area near the central portion of the gear had a coarse grain size, uneven distribution and low strength. Significant metal flow lines at the corner part of the gear indicated that a large number of late-forming metal flowed into the tooth cavity filling the corner portion.

  17. An Experimental and Theoretical Investigation of Micropiiting in Wind Turbine Gears and Bearings

    Energy Technology Data Exchange (ETDEWEB)

    Kahraman, Ahmet

    2012-03-28

    In this research study, the micro-pitting related contact failures of wind turbine gearbox components were investigated both experimentally and theoretically. On the experimental side, a twin-disk type test machine was used to simulate wind turbine transmission contacts in terms of their kinematic (rolling and sliding speeds), surface roughnesses, material parameters and lubricant conditions. A test matrix that represents the ranges of contact conditions of the wind turbine gear boxes was defined and executed to bring an empirical understanding to the micro-pitting problem in terms of key contact parameters and operating conditions. On the theoretical side, the first deterministic micro-pitting model based on a mixed elastohydrodynamic lubrication formulations and multi-axial near-surface crack initiation model was developed. This physics-based model includes actual instantaneous asperity contacts associated with real surface roughness profiles for predicting the onset of the micro-pit formation. The predictions from the theoretical model were compared to the experimental data for validation of the models. The close agreement between the model and measurements was demonstrated. With this, the proposed model can be deemed suitable for identifying the mechanisms leading to micro-pitting of gear and bearing surfaces of wind turbine gear boxes, including all key material, lubricant and surface engineering aspects of the problem, and providing solutions to these micro-pitting problems.

  18. Modeling Noise Sources and Propagation in External Gear Pumps

    Directory of Open Access Journals (Sweden)

    Sangbeom Woo

    2017-07-01

    Full Text Available As a key component in power transfer, positive displacement machines often represent the major source of noise in hydraulic systems. Thus, investigation into the sources of noise and discovering strategies to reduce noise is a key part of improving the performance of current hydraulic systems, as well as applying fluid power systems to a wider range of applications. The present work aims at developing modeling techniques on the topic of noise generation caused by external gear pumps for high pressure applications, which can be useful and effective in investigating the interaction between noise sources and radiated noise and establishing the design guide for a quiet pump. In particular, this study classifies the internal noise sources into four types of effective load functions and, in the proposed model, these load functions are applied to the corresponding areas of the pump case in a realistic way. Vibration and sound radiation can then be predicted using a combined finite element and boundary element vibro-acoustic model. The radiated sound power and sound pressure for the different operating conditions are presented as the main outcomes of the acoustic model. The noise prediction was validated through comparison with the experimentally measured sound power levels.

  19. Two gears of pumping by the sodium pump.

    Science.gov (United States)

    Clarke, Ronald J; Kane, David J

    2007-12-15

    The kinetics of the phosphorylation and subsequent conformational change of Na(+),K(+)-ATPase was investigated via the stopped-flow technique using the fluorescent label RH421 (pH 7.4, 24 degrees C). The enzyme was preequilibrated in buffer containing 130 mM NaCl to stabilize the E1(Na(+))(3) state. On mixing with ATP in the presence of Mg(2+), a fluorescence increase occurred, due to enzyme conversion into the E2P state. The fluorescence change accelerated with increasing ATP concentration until a saturating limit in the hundreds of micromolar range. The amplitude of the fluorescence change (DeltaF/F(0)) increased to 0.98 at 50 microM ATP. DeltaF/F(0) then decreased to 0.82 at 500 microM. The decrease was attributed to an ATP-induced allosteric acceleration of the dephosphorylation reaction. The ATP concentration dependence of the time course and the amplitude of the fluorescence change could not be explained by either a one-site monomeric enzyme model or by a two-pool model. All of the data could be explained by an (alphabeta)(2) dimeric model, in which the enzyme cycles at a low rate with ATP hydrolysis by one alpha-subunit or at a high rate with ATP hydrolysis by both alpha-subunits. Thus, we propose a two-gear bicyclic model to replace the classical monomeric Albers-Post model for kidney Na(+),K(+)-ATPase.

  20. A tribo-dynamic model of a spur gear pair

    Science.gov (United States)

    Li, S.; Kahraman, A.

    2013-09-01

    In this study, a tribo-dynamics model for spur gear pairs is proposed. The model couples a mixed elastohydrodynamic lubrication model of a spur gear pair with a transverse-torsional dynamic model. The lubrication model provides the dynamic model with friction forces and moments that couple the vibrations of the gears along the off-line-of-action direction to other gear vibrations. In addition, it predicts damping coefficient at the gear mesh in a physics-based manner from the energy loss associated with viscous shearing across the fluid film. In return, the dynamic model predicts the dynamic tooth forces and surface velocities to be used in the lubrication model. An iterative computational scheme is proposed to implement the lubrication and dynamics models simultaneously to couple tribological and dynamic behaviors of a spur gear pair fully. An example gear pair is analyzed using the proposed model to demonstrate this two-way relationship and quantify the impact of operating conditions, surface roughness and lubrication characteristics on the tribo-dynamics response. Dynamic gear mesh tooth forces predicted by the dynamic model are used in the EHL model as the loading. Surface velocity fluctuations due to gear vibrations are included in the EHL formulation in the definition of rolling and sliding velocities as well as non-Newtonian flow coefficients. A physics-based, time-varying, viscous gear mesh damping is defined from the EHL formulations to be used in the dynamic model along the OLOA direction. Since the EHL model considers rough surfaces, the roughness effects in addition to the operating speed, load and temperature effects are all included in the gear mesh damping. Time-varying friction forces acting in the OLOA direction and friction moments acting in torsional direction are computed from the EHL model to be used in the dynamic model to couple LOA and OLOA motions properly. Effects of surface roughness and operating speed, load and temperature conditions on

  1. Streamlined Approach for Environmental Restoration (SAFER) Plan for Corrective Action Unit 411. Double Tracks Plutonium Dispersion (Nellis), Nevada Test and Training Range, Nevada, Revision 0

    Energy Technology Data Exchange (ETDEWEB)

    Matthews, Patrick K. [Navarro-Intera, LLC (N-I), Las Vegas, NV (United States)

    2015-03-01

    This Streamlined Approach for Environmental Restoration (SAFER) Plan addresses the actions needed to achieve closure for Corrective Action Unit (CAU) 411, Double Tracks Plutonium Dispersion (Nellis). CAU 411 is located on the Nevada Test and Training Range and consists of a single corrective action site (CAS), NAFR-23-01, Pu Contaminated Soil. There is sufficient information and historical documentation from previous investigations and the 1996 interim corrective action to recommend closure of CAU 411 using the SAFER process. Based on existing data, the presumed corrective action for CAU 411 is clean closure. However, additional data will be obtained during a field investigation to document and verify the adequacy of existing information, and to determine whether the CAU 411 closure objectives have been achieved. This SAFER Plan provides the methodology to gather the necessary information for closing the CAU. The results of the field investigation will be presented in a closure report that will be prepared and submitted to the Nevada Division of Environmental Protection (NDEP) for review and approval. The site will be investigated based on the data quality objectives (DQOs) developed on November 20, 2014, by representatives of NDEP, the U.S. Air Force (USAF), and the U.S. Department of Energy (DOE), National Nuclear Security Administration Nevada Field Office. The DQO process was used to identify and define the type, amount, and quality of data needed to determine whether CAU 411 closure objectives have been achieved. The following text summarizes the SAFER activities that will support the closure of CAU 411; Collect environmental samples from designated target populations to confirm or disprove the presence of contaminants of concern (COCs) as necessary to supplement existing information; If COCs are no longer present, establish clean closure as the corrective action; If COCs are present, the extent of contamination will be defined and further corrective actions

  2. Corrective Action Investigation Plan for Corrective Action Unit 541: Small Boy Nevada National Security Site and Nevada Test and Training Range, Nevada with ROTC 1

    Energy Technology Data Exchange (ETDEWEB)

    Matthews, Patrick [Navarro-Intera, LLC (N-I), Las Vegas, NV (United States)

    2014-09-01

    Corrective Action Unit (CAU) 541 is co-located on the boundary of Area 5 of the Nevada National Security Site and Range 65C of the Nevada Test and Training Range, approximately 65 miles northwest of Las Vegas, Nevada. CAU 541 is a grouping of sites where there has been a suspected release of contamination associated with nuclear testing. This document describes the planned investigation of CAU 541, which comprises the following corrective action sites (CASs): 05-23-04, Atmospheric Tests (6) - BFa Site; 05-45-03, Atmospheric Test Site - Small Boy. These sites are being investigated because existing information on the nature and extent of potential contamination is insufficient to evaluate and recommend corrective action alternatives (CAAs). Additional information will be obtained by conducting a corrective action investigation before evaluating CAAs and selecting the appropriate corrective action for each CAS. The results of the field investigation will support a defensible evaluation of viable CAAs that will be presented in the investigation report. The sites will be investigated based on the data quality objectives (DQOs) developed on April 1, 2014, by representatives of the Nevada Division of Environmental Protection; U.S. Air Force; and the U.S. Department of Energy (DOE), National Nuclear Security Administration Nevada Field Office. The DQO process was used to identify and define the type, amount, and quality of data needed to develop and evaluate appropriate corrective actions for CAU 541. The site investigation process also will be conducted in accordance with the Soils Activity Quality Assurance Plan, which establishes requirements, technical planning, and general quality practices to be applied to this activity. The potential contamination sources associated with CASs 05-23-04 and 05-45-03 are from nuclear testing activities conducted at the Atmospheric Tests (6) - BFa Site and Atmospheric Test Site - Small Boy sites. The presence and nature of

  3. Aerodynamics of a Gulfstream G550 Nose Landing Gear Model

    Science.gov (United States)

    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.

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

    Science.gov (United States)

    Pedersen, N. L.

    2015-06-01

    The strength of a gear is typically defined relative to durability (pitting) and load capacity (tooth-breakage). Tooth-breakage is controlled by the root shape and this gear part can be designed because there is no contact between gear pairs here. The shape of gears is generally defined by 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 is then used to find the cutting tool (the gear envelope) that can create this optimized gear shape. A simple but sufficiently flexible root parameterization is applied and emphasis is put on the importance of separating the shape parameterization from the finite element analysis of stresses. Large improvements in the stress level are found.

  5. Gear crack level identification based on weighted K nearest neighbor classification algorithm

    Science.gov (United States)

    Lei, Yaguo; Zuo, Ming J.

    2009-07-01

    A crack fault is one of the damage modes most frequently occurring in gears. Identifying different crack levels, especially for early cracks is a challenge in gear fault diagnosis. This paper aims to propose a method to classify the different levels of gear cracks automatically and reliably. In this method, feature parameters in time domain, specially designed for gear damage detection and in frequency domain are extracted to characterize the gear conditions. A two-stage feature selection and weighting technique (TFSWT) via Euclidean distance evaluation technique (EDET) is presented and adopted to select sensitive features and remove fault-unrelated features. A weighted K nearest neighbor (W KNN) classification algorithm is utilized to identify the gear crack levels. The gear crack experiments were conducted and the vibration signals were captured from the gears under different loads and motor speeds. The proposed method is applied to identifying the gear crack levels and the applied results demonstrate its effectiveness.

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

    Science.gov (United States)

    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.

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

    Science.gov (United States)

    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.

  8. Artificial Neural Network Model for Monitoring Oil Film Regime in Spur Gear Based on Acoustic Emission Data

    Directory of Open Access Journals (Sweden)

    Yasir Hassan Ali

    2015-01-01

    Full Text Available The thickness of an oil film lubricant can contribute to less gear tooth wear and surface failure. The purpose of this research is to use artificial neural network (ANN computational modelling to correlate spur gear data from acoustic emissions, lubricant temperature, and specific film thickness (λ. The approach is using an algorithm to monitor the oil film thickness and to detect which lubrication regime the gearbox is running either hydrodynamic, elastohydrodynamic, or boundary. This monitoring can aid identification of fault development. Feed-forward and recurrent Elman neural network algorithms were used to develop ANN models, which are subjected to training, testing, and validation process. The Levenberg-Marquardt back-propagation algorithm was applied to reduce errors. Log-sigmoid and Purelin were identified as suitable transfer functions for hidden and output nodes. The methods used in this paper shows accurate predictions from ANN and the feed-forward network performance is superior to the Elman neural network.

  9. Optimizing Gear Performance by Alloy Modification of Carburizing Steels

    Directory of Open Access Journals (Sweden)

    Thomas Tobie

    2017-10-01

    Full Text Available Both the tooth root and tooth flank load carrying capacity are characteristic parameters that decisively influence gear size, as well as gearbox design. The principal requirements towards all modern gearboxes are to comply with the steadily-increasing power density and to simultaneously offer a high reliability of their components. With increasing gear size, the load stresses at greater material depth increase. Thus, the material and particularly the strength properties also at greater material depth gain more importance. The present paper initially gives an overview of the main failure modes of case carburized gears resulting from material fatigue. Furthermore, the underlying load and stress mechanisms, under particular contemplation of the gear size, will be discussed, as these considerations principally define the required material properties. Subsequently, the principles of newly developed, as well as modified alloy concepts for optimized gear steels with high load carrying capacity are presented. In the experimental work, the load carrying capacity of the tooth root and tooth flank was determined using a pulsator, as well as an FZG back-to-back test rig. The results demonstrate the suitability of these innovative alloy concepts.

  10. Advanced Manufacture of Spiral Bevel and Hypoid Gears

    Directory of Open Access Journals (Sweden)

    Vilmos Simon

    2016-11-01

    Full Text Available In this study, an advanced method for the manufacture of spiral bevel and hypoid gears on CNC hypoid generators is proposed. The optmal head-cutter geometry and machine tool settings are determined to introduce the optimal tooth surface modifications into the teeth of spiral bevel and hypoid gears. The aim of these tooth surface modifications is to simultaneously reduce the tooth contact pressure and the transmission errors, to maximize the EHD load carrying capacity of the oil film, and to minimize power losses in the oil film. The proposed advanced method for the manufacture of spiral bevel and hypoid gears is based on machine tool setting variation on the cradle-type generator conducted by optimal polynomial functions and on the use of a CNC hypoid generator. An algorithm is developed for the execution of motions on the CNC hypoid generator using the optimal relations on the cradle-type machine. Effectiveness of the method was demonstrated by using spiral bevel and hypoid gear examples. Significant improvements in the operating characteristics of the gear pairs are achieved.

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

    Science.gov (United States)

    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.

  12. Unilateral maxillary molar distalization with zygoma-gear appliance.

    Science.gov (United States)

    Kilkis, Dogan; Bayram, Mehmet; Celikoglu, Mevlut; Nur, Metin

    2012-08-01

    The aim of this study was to present the orthodontic treatment of a 15-year-old boy with a unilateral maxillary molar distalization system, called the zygoma-gear appliance. It consisted of a zygomatic anchorage miniplate, an inner bow, and a Sentalloy closed coil spring (GAC International, Bohemia, NY). A distalizing force of 350 g was used during the distalization period. The unilateral Class II malocclusion was corrected in 5 months with the zygoma-gear appliance. The maxillary left first molar showed distalization of 4 mm with an inclination of 3°. The maxillary premolars moved distally with the help of the transseptal fibers. In addition, there were slight decreases in overjet (-0.5 mm) and maxillary incisor inclination (-1°), indicating no anchorage loss from the zygoma-gear appliance. Preadjusted fixed appliances (0.022 × 0.028-in, MBT system; 3M Unitek, Monrovia, Calif) were placed in both arches to achieve leveling and alignment. After 14 months of unilateral distalization with the zygoma-gear appliance and fixed appliances, Class I molar and canine relationships were established with satisfactory interdigitation of the posterior teeth. Acceptable overjet and overbite were also achieved. This article shows that this new system, the zygoma-gear appliance, can be used for unilateral maxillary molar distalization without anchorage loss. Copyright © 2012 American Association of Orthodontists. Published by Mosby, Inc. All rights reserved.

  13. Investigation of Spiral Bevel Gear Condition Indicator Validation via AC-29-2C Using Fielded Rotorcraft HUMS Data

    Science.gov (United States)

    Dempsey, Paula J.; Wade, Daniel R.; Antolick, Lance J.; Thomas, Josiah

    2014-01-01

    additional CIs also not in the on-board system, DiffDA1and SI1, also performed well responding to twelve and ten of the fourteen helicopters evaluated respectively. Of the three CIs currently available in the MSPU, DA1, FM4 and SI3, SI3, responded to eight, DA1 responded to six and FM4 responded to four of the fourteen helicopters evaluated. FM4, the poorest performing CI, was not as responsive to damage as the other five CIs. Conversely, when compared to the other two, it was the only CI that responded to damage on two helicopters. CI response could not be correlated to specific failure modes due to limited pictures and subjective descriptions found within the TDA. Flight regime did affect CI response to some gear faults. Due to the range of operating conditions for each regime, more studies are required to determine their sensitivity to regimes.

  14. Initial noise predictions for rudimentary landing gear

    Science.gov (United States)

    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

  15. HBCUs Gear Up to Produce Hospitality Managers.

    Science.gov (United States)

    Murray, Chris

    1994-01-01

    Increasingly, historically black colleges and universities (HBCUs) are developing professional programs in hotel and restaurant management and travel and tourism. One objective is to train African Americans to become owners and operators of their own enterprises. An obstacle is the perception that hospitality careers involve menial labor. (MSE)

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

    DEFF Research Database (Denmark)

    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....

  17. Vibration and noise analysis of a gear transmission system

    Science.gov (United States)

    Choy, F. K.; Qian, W.; Zakrajsek, J. J.; Oswald, F. B.

    1993-01-01

    This paper presents a comprehensive procedure to predict both the vibration and noise generated by a gear transmission system under normal operating conditions. The gearbox vibrations were obtained from both numerical simulation and experimental studies using a gear noise test rig. In addition, the noise generated by the gearbox vibrations was recorded during the experimental testing. A numerical method was used to develop linear relationships between the gearbox vibration and the generated noise. The hypercoherence function is introduced to correlate the nonlinear relationship between the fundamental noise frequency and its harmonics. A numerical procedure was developed using both the linear and nonlinear relationships generated from the experimental data to predict noise resulting from the gearbox vibrations. The application of this methodology is demonstrated by comparing the numerical and experimental results from the gear noise test rig.

  18. 3D MODELLING WITH THE SAMSUNG GEAR 360

    Directory of Open Access Journals (Sweden)

    L. Barazzetti

    2017-02-01

    Full Text Available The Samsung Gear 360 is a consumer grade spherical camera able to capture photos and videos. The aim of this work is to test the metric accuracy and the level of detail achievable with the Samsung Gear 360 coupled with digital modelling techniques based on photogrammetry/computer vision algorithms. Results demonstrate that the direct use of the projection generated inside the mobile phone or with Gear 360 Action Direction (the desktop software for post-processing have a relatively low metric accuracy. As results were in contrast with the accuracy achieved by using the original fisheye images (front and rear facing images in photogrammetric reconstructions, an alternative solution to generate the equirectangular projections was developed. A calibration aimed at understanding the intrinsic parameters of the two lenses camera, as well as their relative orientation, allowed one to generate new equirectangular projections from which a significant improvement of geometric accuracy has been achieved.

  19. Ideas for Testing of Planetary Gear Sets of Automotive Transmissions

    Directory of Open Access Journals (Sweden)

    Achtenová Gabriela

    2017-06-01

    Full Text Available The article describes the concept of modular stand, where is possible to provide tests of gear pairs with fixed axes from mechanical automotive gearboxes, as well as tests of separate planetary sets from automatic gearboxes. Special attention in the article will be paid to the variant dedicated for testing of planetary gear sets. This variant is particularly interesting because: 1 it is rarely described in the literature, and 2 this topology allows big simplification with respect to testing of standard gearwheels. In the planetary closed-loop stand it is possible to directly link two identical planetary sets. Without any bracing flange or other connecting clutches, shafts or gear sets, just two planetary sets face-to-face will be assembled and connected to the electric motor.

  20. Unsteady Simulation of a Landing-Gear Flow Field

    Science.gov (United States)

    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.

  1. Detection of Pitting in Gears Using a Deep Sparse Autoencoder

    Directory of Open Access Journals (Sweden)

    Yongzhi Qu

    2017-05-01

    Full Text Available In this paper; a new method for gear pitting fault detection is presented. The presented method is developed based on a deep sparse autoencoder. The method integrates dictionary learning in sparse coding into a stacked autoencoder network. Sparse coding with dictionary learning is viewed as an adaptive feature extraction method for machinery fault diagnosis. An autoencoder is an unsupervised machine learning technique. A stacked autoencoder network with multiple hidden layers is considered to be a deep learning network. The presented method uses a stacked autoencoder network to perform the dictionary learning in sparse coding and extract features from raw vibration data automatically. These features are then used to perform gear pitting fault detection. The presented method is validated with vibration data collected from gear tests with pitting faults in a gearbox test rig and compared with an existing deep learning-based approach.

  2. Adaptive Wavelet Transform Method to Identify Cracks in Gears

    Directory of Open Access Journals (Sweden)

    Belsak Ales

    2010-01-01

    Full Text Available Many damages and faults can cause problems in gear unit operation. A crack in the tooth root is probably the least desirable among them. It often leads to failure of gear unit operation. By monitoring vibrations, it is possible to determine the presence of a crack. Signals are, however, very noisy. This makes it difficult to define properties of individual components. Wavelet analysis is an effective tool for analysing signals and for defining properties. In this paper, a denoising method based on wavelet analysis, which takes prior information about impulse probability density into consideration, is used to identify transient information from vibration signals of a gear unit with a fatigue crack in the tooth root.

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

    Science.gov (United States)

    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.

  4. Motor integrated permanent magnet gear in a battery electrical vehicle

    DEFF Research Database (Denmark)

    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......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...

  5. Motor Integrated Permanent Magnet Gear in a Battery Electrical Vehicle

    DEFF Research Database (Denmark)

    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......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...

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

    Directory of Open Access Journals (Sweden)

    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.

  7. Electron Beam Welding of Gear Wheels by Splitted Beam

    Directory of Open Access Journals (Sweden)

    Dřímal Daniel

    2014-06-01

    Full Text Available This contribution deals with the issue of electron beam welding of high-accurate gear wheels composed of a spur gearing and fluted shaft joined with a face weld for automotive industry. Both parts made of the high-strength low-alloy steel are welded in the condition after final machining and heat treatment, performed by case hardening, whereas it is required that the run-out in the critical point of weldment after welding, i. e. after the final operation, would be 0.04 mm max..

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

    DEFF Research Database (Denmark)

    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 as logbook data. Here, we take a different approach starting from the gear itself (design and dimensions) to estimate the physical interactions with the seabed at the level of the individual fishing operation. We defined 14 distinct towed gear groups in European waters (eight otter trawl groups, three beam...... trawl groups, two demersal seine groups, and one dredge group), for which we established gear “footprints”. The footprint of a gear is defined as the relative contribution from individual larger gear components, such as trawl doors, sweeps, and groundgear, to the total area and severity of the gear...

  9. 77 FR 14505 - Proposed Information Collection; Comment Request; Gear-Marking Requirement for Atlantic Large...

    Science.gov (United States)

    2012-03-12

    ... required to paint or otherwise mark their gear with one or two color codes, designating the type of gear... techniques or other forms of information technology. Comments submitted in response to this notice will be...

  10. Enhanced Computer Aided Simulation of Meshing and Contact With Application for Spiral Bevel Gear Drives

    National Research Council Canada - National Science Library

    Litvin, F

    1999-01-01

    An integrated tooth contact analysis (TCA) computer program for the simulation of meshing and contact of gear drives that calculates transmission errors and shift of hearing contact for misaligned gear drives has been developed...

  11. Modal Analysis of Worm and Worm Gear Based on ANSYS Workbench

    Directory of Open Access Journals (Sweden)

    Liu Yichang

    2015-01-01

    Full Text Available To establish the three-dimensional model of the worm and worm gear by using SolidWorks. On the worm and worm gear modal analysis is carried out by using finite element analysis software ANSYS Workbench. Obtain the first 6 order natural frequency and vibration mode characteristics of worm and worm gear. Modal analysis laid the foundation for further study on dynamics analysis, Also for the worm and worm gear structure optimization design provides a reference.

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

    DEFF Research Database (Denmark)

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

    otter trawl groups, 3 beam trawl groups, 2 demersal seine groups, and 1 dredge group), for which we established seafloor “footprints”. The footprint of a gear was defined as the relative contribution from individual larger gear components, such as the trawl doors, sweeps and ground gear, to the total...

  13. 46 CFR 58.25-55 - Overcurrent protection for steering-gear systems.

    Science.gov (United States)

    2010-10-01

    ... steering-gear motor, nor a motor for a steering-gear control system, may be protected by an overload... machinery-control station if there is an overload that would cause overheating of the motor. (d) No control circuit of a motor controller, steering-gear control system, or indicating or alarm system may have...

  14. 46 CFR 185.320 - Steering gear, controls, and communication system tests.

    Science.gov (United States)

    2010-10-01

    ... 46 Shipping 7 2010-10-01 2010-10-01 false Steering gear, controls, and communication system tests... gear, controls, and communication system tests. The master of a vessel shall have examined and tested the steering gear, signaling whistle, propulsion controls, and communication systems of the vessel...

  15. 77 FR 37768 - Airworthiness Directives; Aeronautical Accessories, Inc., High Landing Gear Aft Crosstube Assembly

    Science.gov (United States)

    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...) Applicability This AD applies to High Landing Gear Aft Crosstube Assembly (aft crosstube) part number (P/N) 412...

  16. 75 FR 12462 - Fisheries of the Northeastern United States; Northeast Multispecies Fishery; Removal of Gear...

    Science.gov (United States)

    2010-03-16

    ... United States; Northeast Multispecies Fishery; Removal of Gear Restriction for the U.S./Canada Management... (NOAA), Commerce. ACTION: Temporary rule; removal of gear restrictions. SUMMARY: This action removes temporary gear restrictions in both the Eastern and Western U.S./Canada Areas for limited access Northeast...

  17. 76 FR 472 - Harmonization of Airworthiness Standards for Transport Category Airplanes-Landing Gear Retracting...

    Science.gov (United States)

    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 in...

  18. 78 FR 17188 - Agency Information Collection Activities; Comment Request; Evaluation of the GEAR UP College...

    Science.gov (United States)

    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 an...

  19. 76 FR 5402 - Agency Information Collection Activities; Submission for OMB Review; Comment Request; Gear...

    Science.gov (United States)

    2011-01-31

    ...; Gear Certification ACTION: Notice. SUMMARY: The Department of Labor (DOL) hereby announces the... request (ICR) titled, ``Gear Certification,'' to the Office of Management and Budget (OMB) for review and... accredit companies to inspect and provide certification for cranes, derricks, and accessory gear used in...

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

    Science.gov (United States)

    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 operator...

  1. 46 CFR 78.47-55 - Instructions for changing steering gear.

    Science.gov (United States)

    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 clutch...

  2. 77 FR 36998 - Proposed Information Collection; Comment Request; Mandatory Shrimp Vessel and Gear...

    Science.gov (United States)

    2012-06-20

    ... Information Collection; Comment Request; Mandatory Shrimp Vessel and Gear Characterization Survey AGENCY... for the Gulf Shrimp Vessel and Gear Characterization Form may be found at 50 CFR 622.5(a)(1)(iii)(C... shrimp must complete an annual Gulf Shrimp Vessel and Gear Characterization Form. The form will be...

  3. 46 CFR 196.37-33 - Instructions for changing steering gear.

    Science.gov (United States)

    2010-10-01

    ... 46 Shipping 7 2010-10-01 2010-10-01 false Instructions for changing steering gear. 196.37-33... steering gear. (a) Instructions in at least 1/2 inch letters and figures shall be posted in the steering engineroom, relating in order, the different steps to be taken in changing to the emergency steering gear...

  4. 75 FR 58373 - Gaining Early Awareness and Readiness for Undergraduate Programs (GEAR UP)

    Science.gov (United States)

    2010-09-24

    ... Gaining Early Awareness and Readiness for Undergraduate Programs (GEAR UP) AGENCY: Office of Postsecondary... slate for the GEAR UP Program. SUMMARY: The Secretary intends to use the grant slate developed in FY 2008 for the GEAR UP Program authorized by Title IV, Part A of the Higher Education Act of 1965, as...

  5. 78 FR 40436 - Proposed Information Collection; Comment Request; Mandatory Shrimp Vessel and Gear...

    Science.gov (United States)

    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 and...

  6. Gear-based species selectivity and potential interactions between ...

    African Journals Online (AJOL)

    Gear-based species selectivity and potential interactions between artisanal and aquarium fisheries in coastal Kenya: implications for reef fisheries management. Gladys Okemwa, Boaz Kaunda-Arara, Edward Kimani, Benrick Ogotu, Harrison Ong'anda, Clay Obota, Mary Ontomwa ...

  7. 50 CFR 635.6 - Vessel and gear identification.

    Science.gov (United States)

    2010-10-01

    ... 50 Wildlife and Fisheries 8 2010-10-01 2010-10-01 false Vessel and gear identification. 635.6 Section 635.6 Wildlife and Fisheries FISHERY CONSERVATION AND MANAGEMENT, NATIONAL OCEANIC AND ATMOSPHERIC... or aircraft. (ii) In block arabic numerals permanently affixed to or painted on the vessel in...

  8. Experimental Evaluation of a Motor Integrated Permanent Magnet Gear

    DEFF Research Database (Denmark)

    Rasmussen, Peter Omand; Frandsen, Tommy; Jensen, Kasper Køtter

    2011-01-01

    This paper presents test results of a new motor integrated permanent magnet gear and clarifies a path for future optimizations. The prototype, which fabrication also is described, is initially targeting electrical traction for vehicles. Basic measured parameters in form of back-emf, stall torque...

  9. Loss Investigation of Motor Integrated Permanent Magnet Gear

    DEFF Research Database (Denmark)

    Frandsen, Tommy; Rasmussen, Peter Omand

    2014-01-01

    This paper presents an investigation of the eddycurrent losses caused by 3D effects in a Motor Integrated Permanent Magnet Gear (MIPMG). Two prototypes of a MIPMG have been designed and build to be used as traction units for an electric vehicle. The measured efficiency of the MIPMG is superior...

  10. 50 CFR 622.31 - Prohibited gear and methods.

    Science.gov (United States)

    2010-10-01

    ... royal red shrimp in the Gulf EEZ and transfer at sea. A trap may not be used to fish for royal red... Gulf EEZ, and royal red shrimp taken in the Gulf EEZ cannot be transferred at sea regardless of where... gear. The possession of such snapper-grouper while in the water with a rebreather is prima facie...

  11. Dynamics of simple gearing model with flexible planetary pins

    Czech Academy of Sciences Publication Activity Database

    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

  12. 29 CFR 1918.62 - Miscellaneous auxiliary gear.

    Science.gov (United States)

    2010-07-01

    ..., loose gear such as slings, chains, bridles, blocks and hooks shall be so placed as to avoid damage to... supply such ratings, the employer shall use the tables for wire rope and wire rope slings found in... repaired by a sling manufacturer or an entity of similar competence. Each repaired sling shall be proof...

  13. Involute Spur Gear Template Development by Parametric Technique ...

    African Journals Online (AJOL)

    There are many methods available for developing profiles of gear and spline teeth. Most of the techniques are inaccurate because they use only an approximation of the involute curve profile. The parametric method developed in this paper provides accurate involute curve creation using formulas and exact geometric ...

  14. Involute Spur Gear Template Development by Parametric Technique ...

    African Journals Online (AJOL)

    Nekky Umera

    Abstract. There are many methods available for developing profiles of gear and spline teeth. Most of the techniques are inaccurate because they use only an approximation of the involute curve profile. The parametric method developed in this paper provides accurate involute curve creation using formulas and exact ...

  15. LOADING OF MECHANICAL TRANSMISSION OF TROLLEYBUS TRACTION DRIVING GEAR

    Directory of Open Access Journals (Sweden)

    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. 

  16. 50 CFR 635.21 - Gear operation and deployment restrictions.

    Science.gov (United States)

    2010-10-01

    ... considered to have pelagic longline gear on board when a power-operated longline hauler, a mainline, floats capable of supporting the mainline, and leaders (gangions) with hooks are on board. Removal of any one of... initial list specified in paragraph (c)(2)(v)(D) of this section may facilitate opening the turtle's mouth...

  17. Fault diagnosis in gear using wavelet envelope power spectrum ...

    African Journals Online (AJOL)

    An experimental data set is used to compare the diagnostic capability of the fast Fourier transform power spectrum to the wavelet envelope power spectrum as respectively computed using Laplace and Morlet wavelet functions. The gear testing apparatus was used for experimental studies to obtain the vibration signal from ...

  18. PRINCIPLE "EARLY MATCHING" AERODYNAMIC DESIGN AIRCRAFT WITH LANDING GEAR HOVERCRAFT

    Directory of Open Access Journals (Sweden)

    V. P. Morozov

    2015-01-01

    Full Text Available The principle of "early matching" aircraft aerohydrodynamic layouts with air cushion landing gear is suggested. Application of this principle is considered as an example of adaptation to the ball screw base circuit of light transport aircraft. The principle, other than weight, aerodynamic, technological and operational requirements includes additional project activities related to the installation of ball screws.

  19. Innovative Anti Crash Absorber for a Crashworthy Landing Gear

    Science.gov (United States)

    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. Impedance Synthesis Based Vibration Analysis of Geared Transmission System

    Directory of Open Access Journals (Sweden)

    Yafeng Ren

    2017-01-01

    Full Text Available The severity of gear noise response depends on the sensitivity of geared rotor system dynamics to the transmission error. As gearbox design trending towards lighter weight and lower noise, the influence of housing compliance on system dynamic characteristics cannot be ignored. In this study, a gear-shaft-bearing-housing coupled impedance model is proposed to account for the effect of housing compliance on the vibration of geared transmission system. This proposed dynamic model offers convenient modeling, efficient computing, and ability to combine computed parameters with experimental ones. The numerical simulations on system dynamic characteristics are performed for both a rigid housing configuration and a flexible one. Natural frequencies, dynamic mesh forces, and dynamic bearing reaction loads are computed, and the housing compliance contribution on system dynamic characteristics is analyzed. Results show that increasing housing compliance will decrease the system natural frequencies and will affect the dynamic bearing reaction loads significantly but have very little influence on the dynamic mesh force. Also, the analysis shows that bearing stiffness has significant influence on the degree of housing contribution on system dynamic characteristics.

  1. 181 checklist and assessment of efficiency of some traditional gears

    African Journals Online (AJOL)

    CHECKLIST AND ASSESSMENT OF EFFICIENCY OF SOME TRADITIONAL. GEARS AND CRAFTS USED ON RIVER BENUE. R.A. OBANDE, S. OMEJI AND S.K. NYAM. Department of Fisheries And Aquaculture, University Of Agriculture, P.M.B. 2373,. Makurdi, Benue State,. Nigeria. Tel:08061693370 and 08034111161.

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

    CERN Multimedia

    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. Catch composition and efficiency of major fishing gears used in ...

    African Journals Online (AJOL)

    Catch composition and efficiency of major fishing gears viz; gillnets, basket traps, net traps and 'atidza' (brush park), deployed by fishers on the Volta lake at Dzemeni (Stratum II), was assessed over a 16-month period to determine how their deployment can impact on the fish stocks. Fifty thousand seven hundred and ninety ...

  4. The noise generated by a landing gear wheel with hub and rim cavities

    Science.gov (United States)

    Wang, Meng; Angland, David; Zhang, Xin

    2017-03-01

    Wheels are one of the major noise sources of landing gears. Accurate numerical predictions of wheel noise can provide an insight into the physical mechanism of landing gear noise generation and can aid in the design of noise control devices. The major noise sources of a 33% scaled isolated landing gear wheel are investigated by simulating three different wheel configurations using high-order numerical simulations to compute the flow field and the FW-H equation to obtain the far-field acoustic pressures. The baseline configuration is a wheel with a hub cavity and two rim cavities. Two additional simulations are performed; one with the hub cavity covered (NHC) and the other with both the hub cavity and rim cavities covered (NHCRC). These simulations isolate the effects of the hub cavity and rim cavities on the overall wheel noise. The surface flow patterns are visualised by shear stress lines and show that the flow separations and attachments on the side of the wheel, in both the baseline and the configuration with only the hub cavity covered, are significantly reduced by covering both the hub and rim cavities. A frequency-domain FW-H equation is used to identify the noise source regions on the surface of the wheel. The tyre is the main low frequency noise source and shows a lift dipole and side force dipole pattern depending on the frequency. The hub cavity is identified as the dominant middle frequency noise source and radiates in a frequency range centered around the first and second depth modes of the cylindrical hub cavity. The rim cavities are the main high-frequency noise sources. With the hub cavity and rim cavities covered, the largest reduction in Overall Sound Pressure Level (OASPL) is achieved in the hub side direction. In the other directivities, there is also a reduction in the radiated sound.

  5. 76 FR 70695 - Taking and Importing Marine Mammals: U.S. Navy Training in 12 Range Complexes and U.S. Air Force...

    Science.gov (United States)

    2011-11-15

    ... mailing of paper, disk, or CD-ROM comments should be addressed to Michael Payne, Chief, Permits... Cherry Point (CHPT) Range Complex, the Naval Surface Warfare Center Panama City Division (NSWC PCD), the...

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

    Directory of Open Access Journals (Sweden)

    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.

  7. Electromagnetic Design of a New Electrically Controlled Magnetic Variable-Speed Gearing Machine

    Directory of Open Access Journals (Sweden)

    Chunhua Liu

    2014-03-01

    Full Text Available This paper proposes a new electrically controlled magnetic variable-speed gearing (EC-MVSG machine, which is capable of providing controllable gear ratios for hybrid electric vehicle (HEV applications. The key design feature involves the adoption of a magnetic gearing structure and acceptance of the memory machine flux-mnemonic concept. Hence, the proposed machine can not only offer a gear-shifting mechanism for torque and speed transmission, but also provide variable gear ratios for torque and speed variation. The electromagnetic design is studied and discussed. The finite-element method is developed with the hysteresis model to verify the validity of the machine design.

  8. Experimental and analytical investigation of active loads control for aircraft landing gear

    Science.gov (United States)

    Morris, D. L.; Mcgehee, J. R.

    1983-01-01

    A series hydraulic, active loads control main landing gear from a light, twin-engine civil aircraft was investigated. Tests included landing impact and traversal of simulated runway roughness. It is shown that the active gear is feasible and very effective in reducing the force transmitted to the airframe. Preliminary validation of a multidegree of freedom active gear flexible airframe takeoff and landing analysis computer program, which may be used as a design tool for active gear systems, is accomplished by comparing experimental and computed data for the passive and active gears.

  9. DESIGN AND TEST RESULTS FOR MULTIPLE-CONTACT GEAR OF «BELARUS»-TRACTOR TRANSMISSION

    Directory of Open Access Journals (Sweden)

    V. Supin

    2012-01-01

    Full Text Available Gearing with high contact ratio (HCR has other properties than gearing formed with a standard original profile. The gearing is characterized by increased loading capacity. The paper presents a boundary element method (BEM which is applied to solve a problem pertaining to stress concentration at the tooth root. Gear-box casing with multiple-contact gear has remained in series production. Results of the investigations have been realized in the experimental gearbox of  the «Belarus-1523» tractor.

  10. Generation of helical gears with new surfaces topology by application of CNC machines

    Science.gov (United States)

    Litvin, F. L.; Chen, N. X.; Hsiao, C. L.; Handschuh, Robert F.

    1993-01-01

    Analysis of helical involute gears by tooth contact analysis shows that such gears are very sensitive to angular misalignment that leads to edge contact and the potential for high vibration. A new topology of tooth surfaces of helical gears that enables a favorable bearing contact and a reduced level of vibration is described. Methods for grinding of the helical gears with the new topology are proposed. A TCA (tooth contact analysis) program for simulation of meshing and contact of helical gears with the new topology has been developed. Numerical examples that illustrate the proposed ideas are discussed.

  11. Design optimization on the drive train of a light-weight robotic arm

    DEFF Research Database (Denmark)

    Zhou, Lelai; Bai, Shaoping; Hansen, Michael Rygaard

    2011-01-01

    A drive train optimization method for design of light-weight robots is proposed. Optimal selections of motors and gearboxes from a limited catalog of commercially available components are done simultaneously for all joints of a robotic arm. Characteristics of the motor and gearbox, including gear...... ratio, gear inertia, motor inertia, and gear efficiency, are considered in the drive train modeling. A co-simulation method is developed for dynamic simulation of the arm. A design example is included to demonstrate the proposed design optimization method....

  12. Standard conforming involute gear metrology using an articulated arm coordinate measuring system

    Science.gov (United States)

    Härtig, Frank; Lin, Hu; Kniel, Karin; Shi, Zhaoyao

    2012-10-01

    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.

  13. Method for Manufacturing Bulk Metallic Glass-Based Strain Wave Gear Components

    Science.gov (United States)

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

    2017-01-01

    Systems and methods in accordance with embodiments of the invention implement bulk metallic glass-based strain wave gears and strain wave gear components. In one embodiment, a method of fabricating a strain wave gear includes: shaping a BMG-based material using a mold in conjunction with one of a thermoplastic forming technique and a casting technique; where the BMG-based material is shaped into one of: a wave generator plug, an inner race, an outer race, a rolling element, a flexspline, a flexspline without a set of gear teeth, a circular spline, a circular spline without a set of gear teeth, a set of gear teeth to be incorporated within a flexspline, and a set of gear teeth to be incorporated within a circular spline.

  14. A windowing and mapping strategy for gear tooth fault detection of a planetary gearbox

    Science.gov (United States)

    Liang, Xihui; Zuo, Ming J.; Liu, Libin

    2016-12-01

    When there is a single cracked tooth in a planet gear, the cracked tooth is enmeshed for very short time duration in comparison to the total time of a full revolution of the planet gear. The fault symptom generated by the single cracked tooth may be very weak. This study aims to develop a windowing and mapping strategy to interpret the vibration signal of a planetary gear at the tooth level. The fault symptoms generated by a single cracked tooth of the planet gear of interest can be extracted. The health condition of the planet gear can be assessed by comparing the differences among the signals of all teeth of the planet gear. The proposed windowing and mapping strategy is tested with both simulated vibration signals and experimental vibration signals. The tooth signals can be successfully decomposed and a single tooth fault on a planet gear can be effectively detected.

  15. Experiences of how fishers grab opportunities in (more) free regulation of gear

    DEFF Research Database (Denmark)

    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...

  16. IMPROVEMENT OF MATHEMATICAL MODELS FOR ESTIMATION OF TRAIN DYNAMICS

    Directory of Open Access Journals (Sweden)

    L. V. Ursulyak

    2017-12-01

    Full Text Available Purpose. Using scientific publications the paper analyzes the mathematical models developed in Ukraine, CIS countries and abroad for theoretical studies of train dynamics and also shows the urgency of their further improvement. Methodology. Information base of the research was official full-text and abstract databases, scientific works of domestic and foreign scientists, professional periodicals, materials of scientific and practical conferences, methodological materials of ministries and departments. Analysis of publications on existing mathematical models used to solve a wide range of problems associated with the train dynamics study shows the expediency of their application. Findings. The results of these studies were used in: 1 design of new types of draft gears and air distributors; 2 development of methods for controlling the movement of conventional and connected trains; 3 creation of appropriate process flow diagrams; 4 development of energy-saving methods of train driving; 5 revision of the Construction Codes and Regulations (SNiP ΙΙ-39.76; 6 when selecting the parameters of the autonomous automatic control system, created in DNURT, for an auxiliary locomotive that is part of a connected train; 7 when creating computer simulators for the training of locomotive drivers; 8 assessment of the vehicle dynamic indices characterizing traffic safety. Scientists around the world conduct numerical experiments related to estimation of train dynamics using mathematical models that need to be constantly improved. Originality. The authors presented the main theoretical postulates that allowed them to develop the existing mathematical models for solving problems related to the train dynamics. The analysis of scientific articles published in Ukraine, CIS countries and abroad allows us to determine the most relevant areas of application of mathematical models. Practicalvalue. The practical value of the results obtained lies in the scientific validity

  17. Investigation about crack propagation paths in thin rim gears

    Directory of Open Access Journals (Sweden)

    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

  18. The Effect of Temperature in Induction Surface Hardening on the Distortion of Gear

    Science.gov (United States)

    Guterres, N. F. D. S.; Rusnaldy; Widodo, A.

    2017-05-01

    One way to extend the lifetime of gear is minimizing the distortion during the manufacturing process. One of the most important processes in gear manufacturing is induction surface hardening. Induction hardening causes a geometric distortion in gears. This study aimed to analyze the distortion of the gear after induction surface hardening. The material of gear that used in this research is S45C, and it was designed with the a module (m) of 1.75, and 29 teeth (z). In the experiment, the gear was heat-treated using induction hardening at variations of temperatures of 820, 880, and 920 °C with holding time was 35, 45, and 55 s, respectively. Then the gear quenched in water at room temperature. The microstructure analysis was conducted to explore the phase change in gear teeth. Hardness test was also performed on the gear using Rockwell test, and finally, the gear dimension was evaluated. The results showed that the hardness of gear at the teeth surface was 64.9 HRC at the case depth of 5 mm is proper to be used. The microstructure of gear at the surface is martensitic, and the deeper area is pearlite. Gear distortion of all teeth with average thickness was reduced and the highest value was 1.593% at the austenite temperature of 820 °C. While the highest reduction was produced at the temperature of 920 °C and generated the highest shrinkage. The induction surface hardening of the gear was not high, and the highest distortion was found in the outside diameter.

  19. Using continuation analysis to identify shimmy-suppression devices for an aircraft main landing gear

    Science.gov (United States)

    Li, Yuan; Howcroft, Chris; Neild, Simon A.; Jiang, Jason Zheng

    2017-11-01

    This paper considers several passive shimmy-suppression devices for a dual-wheel main landing gear (MLG) and proposes a method of selecting the device parameter values for which no shimmy occurs. Two of these devices include an inerter, a novel mechanical element with the property that the applied force is proportional to the relative acceleration between its terminals. A nonlinear mathematical model is developed to represent the MLG dynamics. A bifurcation study is then carried out to investigate the effects of the shimmy-suppression devices on the gear steady-state response. The aircraft forward speed and the device damping are chosen as the continuation parameters. A range of device parameter values that ensure the aircraft is free from shimmy instability for any forward speed within its operating region are identified. It is shown that the use of a proposed spring-damper configuration can result in a more robust device in terms of the device damping over that of a conventional shimmy damper. Two inerter-based shimmy-suppression devices are then considered and yield further benefits on expanding the zero-shimmy regions in the two-parameter bifurcation diagrams.

  20. Material Compressing Test of the High Polymer Part Used in Draft Gear of Heavy Load Locomotive

    Directory of Open Access Journals (Sweden)

    Wei Yangang

    2016-01-01

    Full Text Available According to the actual load cases of heavy load locomotive, the material compressing tests of the high polymer parts used in the locomotive are researched. The relationship between stress and strain during the material compressing are acquired by means of comparing the many results of the material compressing tests under different test condition. The relationship between stress and strain during the material compressing is nonlinear in large range of strain, but the relationship is approximately linear in small range of strain. The material of the high polymer made in China and the material of the high polymer imported are compared through the tests. The results show that the compressing property of the material of the high polymer made in China and the material of the high polymer imported are almost same. The research offers the foundation to study the structure elasticity of the draft gear.

  1. Performance evaluation on vibration control of MR landing gear

    Energy Technology Data Exchange (ETDEWEB)

    Lee, D Y; Nam, Y J; Park, M K [Graduate School, Pusan National University, Busan 609-735 (Korea, Republic of); Yamane, R [Kokushikan University, 4-28-1 Setagaya, Setagaya-ku, Tokyo 154-8515 (Japan)], E-mail: ldy5577@yahoo.co.kr, E-mail: mkpark1@pusan.ac.kr

    2009-02-01

    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. Study Of Gear Teeth Distortions Due To Heat Treatment

    Directory of Open Access Journals (Sweden)

    V. Khade

    2015-02-01

    Full Text Available Abstract The work aims to study the distortion occurred due to heat treatment on the Gear teeth. The paper studies various causes of distortion control techniques to eliminate distortion which includes changes in design selection of material heat treatment process mainly due to quenching that includes cooling rates quenching mediums fixtures. An experimental study and results conducted for the effects of the distortion on the Gear teeth and to reduce the distortion with certain changes design modification resulting in shape amp size changes phase changes changes in hardness microstructure and residual stresses. It is observed that adequate velocity of quench oil around the component to be heat treated ensures uniform amp desired cooling rate as per heat treatment cycle. Modification in design of baffles achieved the adequate velocity and minimization of distortion. Also Fixtures for holding finished parts or assemblies during heat treatment may be either support or restraint type to control dimensional relations during aging.

  3. Differential Evolution Algorithm for Gear Ratio Optimization of Vehicles

    Directory of Open Access Journals (Sweden)

    İlker Küçükoğlu

    2016-10-01

    Full Text Available In this study, the gear ratio optimization problem for the vehicles is considered to minimize total fuel consumption amount for a given distance and road gradient. The aim of the study is to find best gear ratio values for a gearbox that provide the best consumption value for the vehicle. In order to analyze the fuel consumption changes for a gearbox, fuel consumption formulations, which have a nonlinear structure, are presented based on the total energy requirement of the vehicle. To solve this nonlinear optimization problem, a differential evolution algorithm (DEA is proposed which is one of the popular evolutionary optimization algorithms. In computational studies, the DEA is tested on a vehicle set by considering different road conditions. The results of the experiments show that the proposed DEA is capable to find effective solutions for the problem where an improvement is obtained for each experiment according to the real fuel consumption amount of the vehicles given at their technical reports

  4. Survey gear calibration independent of spatial fish distribution

    DEFF Research Database (Denmark)

    Lewy, Peter; Nielsen, J. Rasmus; Hovgård, Holger

    2004-01-01

    Trawl surveys provide important information for evaluation of relative stock abundance fluctuations over time. Therefore, when survey gears or vessels are changed, it is important to compare the efficiency and selectivity of old and new gears and vessels. A method for estimation of conversion...... and disturbance parameters with their precision are obtained using standard software. Simulation studies carried out additionally showed that the estimated conversion factors were practically unbiased. Because of the independence of the spatial fish distribution, the new method is preferable to the traditional...... paired hauls design for which it is generally not possible to obtain the statistical properties of the estimated conversion factors. The paper is concluded with suggestions on how to optimize survey design. The method was used to estimate conversion factors for Atlantic cod (Gadus morhua) from Danish...

  5. Achievements of Study Concerning Worm Face Gear Made in Romania

    Directory of Open Access Journals (Sweden)

    Vasile Boloş

    2010-12-01

    Full Text Available Worm face gears are a relatively new category of gear failure in 50 years in the USA. They are composed of a conical or cylindrical worm to engage the front wheel of a conical or flat. Geometric configuration to ensure a great contact ratio and lubrication between the flanks favorable conditions which allow their implementation of hardened steel, gray iron, bronze. Also they will produce big rapport of transmission in a single stage. Originally conceived by Illinois Tool Works Company Chicago they were taken and developed at the Institute of Mechanical Izhevsk (Russia. Experimental and theoretical developments were made in Britain, Germany, Hungary, Poland, Bulgaria and Romania. In the present paper is highlighted the concerns and the achievements of researchers from Romania in the period 1980-2009.

  6. Final Environmental Assessment Eglin Gulf Test and Training Range (EGTTR) Precision Strike Weapons (PSW) Test (5-Year Plan) Eglin Air Force Base, Florida

    Science.gov (United States)

    2005-11-01

    Rachycentridae Cobia Sciaenidae Drums Sphymidae Hammerhead sharks Tropical Sphyraenidae Barracudas Fishes of the eastern Gulf can be characterized by...Dusky shark Carcharinus obscurus C One of the larger shark species of continental shelf waters; occurs in Atlantic and Pacific. Feeds on fish...other sharks , rays, squid, octopus, and starfish. Sand tiger shark Odontaspis taurus C In North America, the sand tiger ranges from the Gulf of

  7. Final Environmental Assessment for the Integrated Natural Resources Management Plan for Nellis Air Force Base, Creech Air Force Base, and the Nevada Test And Training Range, NV

    Science.gov (United States)

    2008-06-01

    are considered invasive species. The three most promi- nent annual invasives are tumbleweed or Russian thistle (Sa/so/a tragus) , red brome (Bromus...rubens), and cheat-grass (8. tectorum) . Red brome is desert-adapted and has become com- mon on the South Range, while cheat-grass is adapted to cooler...unaffected by EuroAmerican activities. Russian thistle, red brome , and cheat-grass are aggressive colonizers on disturbed soils, and they have

  8. Planetary gear profile modification design based on load sharing modelling

    Science.gov (United States)

    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.

  9. VERIFICATION OF GEAR DYNAMIC MODEL IN DIFFERENT OPERATING CONDITIONS

    Directory of Open Access Journals (Sweden)

    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.

  10. Testing Aerospace Gears for Bending Fatigue, Pitting, and Scuffing

    Science.gov (United States)

    Krantz, Timothy; Anderson, Cody; Shareef, Iqbal; Fetty, Jason

    2017-01-01

    This work was motivated by the goal to increase the power to weight ratio of rotorcraft drive systems. Experiments were conducted to establish the performance of gears made from an aerospace alloy used in production aircraft. Bending fatigue, pitting, and scuffing test procedures and results are documented. The data establishes a baseline for evaluation of new technologies. Recommendations are made to improve test procedures for future work.

  11. Active control landing gear for ground loads alleviation

    Science.gov (United States)

    Mcgehee, J. R.

    1985-01-01

    An active landing gear has been created by connecting the hydraulic piston in an oleo strut to a hydraulic supply. A controller modulates the pressure in the oleo to achieve the desired dynamic characteristics. Tests on ground rigs (documented by a film) have demonstrated the successful alleviation of induced structural ground loads and the next step will be a flight test using a fighter aircraft.

  12. Use of Protective Gear in Bird Flu Outbreak Response

    Centers for Disease Control (CDC) Podcasts

    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.

  13. Load gear shift in the i{sup 2} transmission of the Autarkic Hybrid; Der Lastschaltvorgang am i{sup 2}-Getriebe des Autarken Hybrid

    Energy Technology Data Exchange (ETDEWEB)

    Foerster, W.J.; Hoehn, B.R.; Pflaum, H.

    1999-07-01

    A central characteristic of the Autarkic Hybrid is the use of infinitely variable contact transmission with a wide spread of gear ratios - the i{sup 2} transmission. A significant extension of the spread in this transmission is realised by the double use of the chain converter operating range. This requires a gear shift that can be carried out as so-called load gear shift without interrupting the tractive force. This type of gear shift has hardly been researched. Therefore basic thoughts for its realisation are explained first. Since the i{sup 2} transmission is of central importance for the total hybrid drive system it is tested on an especially designed test stand. The investigation is going to focus on the general transmission functions before a load gear shift is carried out. A quasi static calculation model that has been calibrated according to the measurements enables the pre-determination of appropriate control parameter for a systematic optimisation of the load gear shift. (orig.) [German] Ein zentrales Merkmal des Autarken Hybrid ist die Verwendung eines stufenlosen Umschlingungsgetriebes mit weiter Spreizung - dem i{sup 2}-Getriebe. An diesem Getriebe wird eine signifikante Spreizungserweiterung durch zweifache Nutzung des Kettenwandler-Stellbereichs erzielt. Hierzu ist ein Umschaltvorgang erforderlich, der ohne Zugkraftunterbrechung als sog. Lastschaltvorgang realisiert werden soll und in dieser Form weitgehend unerforscht ist. Daher werden zunaechst grundlegende Gedanken fuer dessen Realisierung erlaeutert. Wegen der zentralen Bedeutung des i{sup 2}-Getriebes fuer den gesamten Hybrid-Antriebsstrang wird dieses an einem speziell hierfuer konzipierten Pruefstand experimentell untersucht. Dabei stand zunaechst die generelle Getriebefunktion im Mittelpunkt der Untersuchungen, bevor die Durchfuehrung eines Lastschaltvorgangs erfolgte. Ein an den Messungen kalibiriertes, quasistatisches Rechenmodell ermoeglicht sodann Vorausbestimmung geeigneter

  14. Die design and process optimization of plastic gear extrusion

    Science.gov (United States)

    Zhang, Lei; Fu, Zhihong; Yao, Chen; Zang, Gongzheng; Wan, Yue

    2018-01-01

    The flow velocity of the melt in the extruder was simulated by using software Polyflow, and the size of the die channel with the best flow uniformity was obtained. The die profile shape is obtained by reverse design. The length of the shaping section is determined by Ansys transient thermal analysis. According to the simulation results, the design and manufacture of extrusion die of plastic gear and vacuum cooling setting were obtained. The influence of the five process parameters on the precision of the plastic gear were studied by the single factor analysis method, such as the die temperature T, the screw speed R, the die spacing S, the vacuum degree M and the hauling speed V. The optimal combination of process parameters was obtained by using the neural network particle swarm optimization algorithm(T = 197.05 °C, R = 9.04rpm, S = 67mm, M = ‑0.0194MPa). The tooth profile deviation of the extruded plastic gear can reach 9 level of accuracy.

  15. Food-related advertising geared toward Mexican children.

    Science.gov (United States)

    Ramírez-Ley, Karla; De Lira-García, Cynthia; Souto-Gallardo, María de las Cruces; Tejeda-López, María Fernanda; Castañeda-González, Lidia Magdalena; Bacardí-Gascón, Montserrat; Jiménez-Cruz, Arturo

    2009-09-01

    Overweight and obesity have dramatically increased in recent years. In 2006, the prevalence of overweight and obesity among 6- to 12-year-old children was 26% in Mexico. Food advertising has shown to be a contributor to childhood obesity. The purpose of this study was to evaluate the frequency and types of food advertisements geared toward children living in Baja California. Two local channels and three national channels, during a period of 7 h on weekday afternoons and 6 h on weekend mornings, were recorded for 7 days. A total of 235 h were recorded and analyzed. A total of 8299 advertisements were registered; 22% were food-related and 50% were geared toward children. The average of food-related advertisements (FRAs) per half an hour was 4, and half of them were geared toward children. During the time that children may be watching television, 50% of all FRAs were potato and corn chips, desserts and cakes, juices, sweetened cereals, candies, cookies, sweetened beverages and fast foods, which comprises a higher percentage of adult-oriented FRA (32 versus 22%). Children are systematically more exposed than adults to advertisements for high-energy-dense foods.

  16. Numerical Simulation of Oil Jet Lubrication for High Speed Gears

    Directory of Open Access Journals (Sweden)

    Tommaso Fondelli

    2015-01-01

    Full Text Available The Geared Turbofan technology is one of the most promising engine configurations to significantly reduce the specific fuel consumption. In this architecture, a power epicyclical gearbox is interposed between the fan and the low pressure spool. Thanks to the gearbox, fan and low pressure spool can turn at different speed, leading to higher engine bypass ratio. Therefore the gearbox efficiency becomes a key parameter for such technology. Further improvement of efficiency can be achieved developing a physical understanding of fluid dynamic losses within the transmission system. These losses are mainly related to viscous effects and they are directly connected to the lubrication method. In this work, the oil injection losses have been studied by means of CFD simulations. A numerical study of a single oil jet impinging on a single high speed gear has been carried out using the VOF method. The aim of this analysis is to evaluate the resistant torque due to the oil jet lubrication, correlating the torque data with the oil-gear interaction phases. URANS calculations have been performed using an adaptive meshing approach, as a way of significantly reducing the simulation costs. A global sensitivity analysis of adopted models has been carried out and a numerical setup has been defined.

  17. An Artificial Intelligence Approach for Gears Diagnostics in AUVs.

    Science.gov (United States)

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

    2016-04-12

    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 studies have been carried out on these kinds of gears. In this paper, an experimental platform has been adapted for the study and several samples have been prepared. Moreover, several vibration signals have been measured and their time-frequency characteristics have been taken as inputs to the diagnostic system. In fact, a diagnostic system based on an artificial intelligence strategy has been devised. Furthermore, techniques based on several paradigms of the Artificial Intelligence (Neural Networks, Fuzzy systems and Genetic Algorithms) have been applied altogether in order to design an efficient fault diagnostic system. A hybrid Genetic Neuro-Fuzzy system has been developed, where it is possible, at the final stage of the learning process, to express the fault diagnostic system as a set of fuzzy rules. Several trials have been carried out and satisfactory results have been achieved.

  18. An Artificial Intelligence Approach for Gears Diagnostics in AUVs

    Directory of Open Access Journals (Sweden)

    Graciliano Nicolás Marichal

    2016-04-01

    Full Text Available 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 studies have been carried out on these kinds of gears. In this paper, an experimental platform has been adapted for the study and several samples have been prepared. Moreover, several vibration signals have been measured and their time-frequency characteristics have been taken as inputs to the diagnostic system. In fact, a diagnostic system based on an artificial intelligence strategy has been devised. Furthermore, techniques based on several paradigms of the Artificial Intelligence (Neural Networks, Fuzzy systems and Genetic Algorithms have been applied altogether in order to design an efficient fault diagnostic system. A hybrid Genetic Neuro-Fuzzy system has been developed, where it is possible, at the final stage of the learning process, to express the fault diagnostic system as a set of fuzzy rules. Several trials have been carried out and satisfactory results have been achieved.

  19. An Artificial Intelligence Approach for Gears Diagnostics in AUVs

    Science.gov (United States)

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

    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 studies have been carried out on these kinds of gears. In this paper, an experimental platform has been adapted for the study and several samples have been prepared. Moreover, several vibration signals have been measured and their time-frequency characteristics have been taken as inputs to the diagnostic system. In fact, a diagnostic system based on an artificial intelligence strategy has been devised. Furthermore, techniques based on several paradigms of the Artificial Intelligence (Neural Networks, Fuzzy systems and Genetic Algorithms) have been applied altogether in order to design an efficient fault diagnostic system. A hybrid Genetic Neuro-Fuzzy system has been developed, where it is possible, at the final stage of the learning process, to express the fault diagnostic system as a set of fuzzy rules. Several trials have been carried out and satisfactory results have been achieved. PMID:27077868

  20. Preparing New Jersey Students for College and Careers: Evaluation of New Jersey GEAR UP. New Jersey Gear Up: Gaining Early Awareness and Readiness for Undergraduate Programs

    Science.gov (United States)

    New Jersey Commission on Higher Education, 2005

    2005-01-01

    The evaluator finds that New Jersey GEAR UP is an outstanding example of student focused academic development, providing low income and disadvantaged middle school through high school cohorts the skills, knowledge and individual self confidence and aspiration that leads to postsecondary academic success.New Jersey GEAR UP: has met, or nearly met,…

  1. Molecular Dynamics Simulation of a Multi-Walled Carbon Nanotube Based Gear

    Science.gov (United States)

    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

  2. Injection molded plastic helical gear filled with carbon powder made from rice hull

    Science.gov (United States)

    Chen, Yen Chu; Itagaki, Takayoshi; Takahashi, Hideo; Takahashi, Mikio

    2017-07-01

    Natural materials are focused on the ecological responsibility, all over the world. The rice-hull contains natural silica about 20 wt.%. Therefore, a carbonized rice-hull; Rice-Hull-Silica-Carbon (RHSC) is focused as effective utilization of the discarded rice hull. In this study, test plastic helical gears were made form polyacetal copolymer filled with RHSC powder by injection molding. Test helical gears were operated on endurance test. The bulk temperature and noise of test gears were measured during gears operation. Then, the tooth damage of test gears were investigated by using optical microscope. It is clarified that difference of tooth damage by kind of test gears. Moreover, the transition of gear bulk temperature and noise during operation are investigated. Based on these results, the effect of RHSC powder is discussed. From the discussions, it seems reasonable to conclude : (1) The heat resistance of plastic gear is improved by adding the RHSC powder. (2) The fatigue life of plastic gear is improved by adding suitable amount of the RHSC powder. (3) The sound pressure level of plastic gear is reduced by adding the smaller median grain diameter of RHSC powder.

  3. A New Model of the Fractional Order Dynamics of the Planetary Gears

    Directory of Open Access Journals (Sweden)

    Vera Nikolic-Stanojevic

    2013-01-01

    Full Text Available A theoretical model of planetary gears dynamics is presented. Planetary gears are parametrically excited by the time-varying mesh stiffness that fluctuates as the number of gear tooth pairs in contact changes during gear rotation. In the paper, it has been indicated that even the small disturbance in design realizations of this gear cause nonlinear properties of dynamics which are the source of vibrations and noise in the gear transmission. Dynamic model of the planetary gears with four degrees of freedom is used. Applying the basic principles of analytical mechanics and taking the initial and boundary conditions into consideration, it is possible to obtain the system of equations representing physical meshing process between the two or more gears. This investigation was focused to a new model of the fractional order dynamics of the planetary gear. For this model analytical expressions for the corresponding fractional order modes like one frequency eigen vibrational modes are obtained. For one planetary gear, eigen fractional modes are obtained, and a visualization is presented. By using MathCAD the solution is obtained.

  4. Optimal design for an end face engagement worm gear with multiple worm-wheel meshing

    Science.gov (United States)

    Deng, Xingqiao; Zhu, Weibing; Chen, Yonghong; Chen, Shouan; Wang, Jinge

    2017-01-01

    To solve the problem for lacking a special mechanical transmission that could provide multiple outputs with high transmission efficiency and good lubrication in the modern industrial, a novel worm gear, named end face engagement worm gear, with multiple worm-wheel meshing is proposed for the first time. The essential parameters for the worm gear are optimized to enhance lubrication and meshing properties. Moreover, analysis of variance(ANOVA) is applied to determine the optimum levels and to determine the influence of parameters. The ANOVA results show that the novel end face engagement worm gear with multiple worm wheels provides high lubrication(the lubrication angle is more than 89°) and meshing performance(the induce normal curvature is less than 0.0002 mm-1). The interaction between center distance and roller slant distance most strongly influences the lubrication angle(contributed 51.6%), followed by the parameters of center distance(contributed 25.0%), roller slant distance(contributed 16.4%), tooth angle of gear, gear ratio, and roller radius. In addition, roller radius most strongly influences the induced normal curvature(contributed 39.4%), followed by roller slant distance(contributed 15.2%), tooth angle of the gear(contributed 9.0%), center distance, and gear ratio. The proposed worm gear helps to enrich the no-backlash high precision worm drive and the optimal design method can provide a useful reference on performance improvement of other worm gear.

  5. Effect of the cutter parameters and machining parameters on the interference in gear slicing

    Science.gov (United States)

    Chen, Xinchun; Li, Jia; Lou, Benchao; Shi, Jiang; Yang, Qijun

    2013-11-01

    Current researches have not yet found the effect law of the cutter parameters and machining parameters on the interference in gear slicing, the interference between the cutter and machined gear often happens because the appropriate cutter parameters and machining parameters cannot be set, which reduces the gear machining accuracy. The relative position between the major flank face and edge-sweeping surface, distribution law of the interference area in forming process of edge-sweeping surface, and effect law of relative positions among edge-sweeping surfaces on the interference are studied by graphical analysis. The effect law of the cutter parameters and machining parameters on the interference is found. The effect law shows that the interference in gear slicing can be controlled when the relief angle measured on the top edge and feed of every rotation are chosen respectively larger than 9° and smaller than 0.15 mm/r. An internal helical gear is sliced with the spur slice cutter and the cutter parameters and machining parameters are set based on above the effect law. The machined gear is measured in Gear Measuring Center and the detection result shows that the comprehensive accuracy reaches GB/T Class 7, where some reach GB/T Class 6. The result can meet the gear machining accuracy requirement and shows that the effect law found is valid. The problem of the interference in gear slicing is solved and the gear machining accuracy can be improved.

  6. The Design of Intelligent Repair Welding Mechanism and Relative Control System of Big Gear

    Directory of Open Access Journals (Sweden)

    Hong-Yu LIU

    2014-10-01

    Full Text Available Effective repair of worn big gear has large influence on ensuring safety production and enhancing economic benefits. A kind of intelligent repair welding method was put forward mainly aimed at the big gear restriction conditions of high production cost, long production cycle and high- intensity artificial repair welding work. Big gear repair welding mechanism was designed in this paper. The work principle and part selection of big gear repair welding mechanism was introduced. The three dimensional mode of big gear repair welding mechanism was constructed by Pro/E three dimensional design software. Three dimensional motions can be realized by motor controlling ball screw. According to involute gear feature, the complicated curve motion on curved gear surface can be transformed to linear motion by orientation. By this way, the repair welding on worn gear area can be realized. In the design of big gear repair welding mechanism control system, Siemens S7-200 series hardware was chosen. Siemens STEP7 programming software was chosen as system design tool. The entire repair welding process was simulated by experiment simulation. It provides a kind of practical and feasible method for the intelligent repair welding of big worn gear.

  7. Gear wear monitoring by modulation signal bispectrum based on motor current signal analysis

    Science.gov (United States)

    Zhang, Ruiliang; Gu, Fengshou; Mansaf, Haram; Wang, Tie; Ball, Andrew D.

    2017-09-01

    Gears are important mechanical components for power transmissions. Tooth wear is one of the most common failure modes, which can present throughout a gear's lifetime. It is significant to accurately monitor gear wear progression in order to take timely predictive maintenances. Motor current signature analysis (MCSA) is an effective and non-intrusive approach which is able to monitor faults from both electrical and mechanical systems. However, little research has been reported in monitoring the gear wear and estimating its severity based on MCSA. This paper presents a novel gear wear monitoring method through a modulation signal bispectrum based motor current signal analysis (MSB-MCSA). For a steady gear transmission, it is inevitable to exist load and speed oscillations due to various errors including wears. These oscillations can induce small modulations in the current signals of the driving motor. MSB is particularly effective in characterising such small modulation signals. Based on these understandings, the monitoring process was implemented based on the current signals from a run-to-failure test of an industrial two stages helical gearbox under a moderate accelerated fatigue process. At the initial operation of the test, MSB analysis results showed that the peak values at the bifrequencies of gear rotations and the power supply can be effective monitoring features for identifying faulty gears and wear severity as they exhibit agreeable changes with gear loads. A monotonically increasing trend established by these features allows a clear indication of the gear wear progression. The dismantle inspection at 477 h of operation, made when one of the monitored features is about 123% higher than its baseline, has found that there are severe scuffing wear marks on a number of tooth surfaces on the driving gear, showing that the gear endures a gradual wear process during its long test operation. Therefore, it is affirmed that the MSB-MSCA approach proposed is reliable

  8. Face, content, construct and concurrent validity of dry laboratory exercises for robotic training using a global assessment tool.

    Science.gov (United States)

    Ramos, Patrick; Montez, Jeremy; Tripp, Adrian; Ng, Casey K; Gill, Inderbir S; Hung, Andrew J

    2014-05-01

    To evaluate robotic dry laboratory (dry lab) exercises in terms of their face, content, construct and concurrent validities. To evaluate the applicability of the Global Evaluative Assessment of Robotic Skills (GEARS) tool to assess dry lab performance. Participants were prospectively categorized into two groups: robotic novice (no cases as primary surgeon) and robotic expert (≥30 cases). Participants completed three virtual reality (VR) exercises using the da Vinci Skills Simulator (Intuitive Surgical, Sunnyvale, CA, USA), as well as corresponding dry lab versions of each exercise (Mimic Technologies, Seattle, WA, USA) on the da Vinci Surgical System. Simulator performance was assessed by metrics measured on the simulator. Dry lab performance was blindly video-evaluated by expert review using the six-metric GEARS tool. Participants completed a post-study questionnaire (to evaluate face and content validity). A Wilcoxon non-parametric test was used to compare performance between groups (construct validity) and Spearman's correlation coefficient was used to assess simulation to dry lab performance (concurrent validity). The mean number of robotic cases experienced for novices was 0 and for experts the mean (range) was 200 (30-2000) cases. Expert surgeons found the dry lab exercises both 'realistic' (median [range] score 8 [4-10] out of 10) and 'very useful' for training of residents (median [range] score 9 [5-10] out of 10). Overall, expert surgeons completed all dry lab tasks more efficiently (P concurrent validity with the corresponding VR tasks. Until now, the assessment of dry lab exercises has been limited to basic metrics (i.e. time to completion and error avoidance). For the first time, we have shown it is feasibile to apply a global assessment tool (GEARS) to dry lab training. © 2013 The Authors. BJU International © 2013 BJU International.

  9. Solar Training Network and Solar Ready Vets

    Energy Technology Data Exchange (ETDEWEB)

    Dalstrom, Tenley Ann

    2016-09-14

    In 2016, the White House announced the Solar Ready Vets program, funded under DOE's SunShot initiative would be administered by The Solar Foundation to connect transitioning military personnel to solar training and employment as they separate from service. This presentation is geared to informing and recruiting employer partners for the Solar Ready Vets program, and the Solar Training Network. It describes the programs, and the benefits to employers that choose to connect to the programs.

  10. The impact of various distance between axes of worm gear on torque value. Worm gear test stand

    Science.gov (United States)

    Sobek, M.; Baier, A.; Grabowski, Ł.

    2017-08-01

    Transferring both rotational and translational movements in systems used in the automotive industry is a very important and complex issue. In addition, the situation becomes much more difficult and complicated when the design of the transition system requires a high precision of operation as well as a well definite and long operating life. Such requirements are imposed on all components of today’s motor vehicles. However, particular attention is paid to the elements that directly or indirectly affect the safety of persons traveling in the vehicle. Such components are undoubtedly components included as parts of the steering system of the vehicle. Power steering systems have been present in motor vehicles for more than a century. They go through continuous metamorphosis and they are getting better and better. Current power steering systems are based on an electric motor and some kind of transmission. Depending on the position of the drive relative to the steering column, different configurations of the transmission are used. This article will cover issues related to tests of power steering gearing using a worm drive. The worm drive is a very specific example of a propulsion system that uses twisted axles. Normally, in this type of transition you can find two gear units with the axis mounted with a 90° angle between. The components of the worm drive are a worm and a worm gear, also called a worm wheel. In terms of the geometrical form, the worm resembles a helical spur gear. The shape of the worm is similar to the shape of a screw with a trapezoidal thread. A correct matching of these two components ensures proper operation of the entire transmission. Incorrect positioning of the components in relation to each other can significantly reduce the lifetime of the drive unit, and also lead to abnormal work, eg by raising the noise level. This article describes a test method of finding the appropriate distance between the axles of both worm drive units by testing the

  11. On the Influence of Force Distribution and Boundary Condition on Helical Gear Stiffness

    DEFF Research Database (Denmark)

    Pedersen, Niels Leergaard

    2015-01-01

    The gear stiffness has a direct influence on the dynamic response of transmission systems that include a gear box, the stiffness also controls the load distribution among the teeth in mesh. The stiffness of a gear tooth varies non-linearly as the contact line with the meshing gear tooth moves along...... influence on the stiffness. These two factors are the rim thickness included in the stiffness calculation and the contact zone size. In the contact zone the distribution of the load is also shown to be important. Simple possible simplications in relation to the contact load distribution are presented....... The gear stiffness is found using the elastic energy of the loaded tooth. In the nite element calculation the true gear tooth root profile is applied....

  12. Optimum Design of 1st Gear Ratio for 4WD Vehicles Based on Vehicle Dynamic Behaviour

    Directory of Open Access Journals (Sweden)

    M. H. Shojaeefard

    2013-01-01

    Full Text Available This paper presents an approach that allows optimizing gear ratio and vehicle dimension to achieve optimum gear transmission. Therefore, augmented Lagrangian multiplier method, defined as classical method, is utilized to find the optimum gear ratios and the corresponding number of gear teeth applied to all epicyclical gears. The new method is able to calculate and also to optimize the gear ratio based on dynamics of 4WD vehicles. Therefore, 4WD vehicles dynamic equations are employed assuming that the rear wheels or the front wheels are at the point of slip. In addition, a genetic algorithm is modified to preserve feasibility of the encountered solutions. The basic dimension of a sample commercial vehicle (2009 hummer H3 4dr AWD SUV and its gearbox are optimized, and then the effects of changing slip angle, wheel base, and engine torque on optimum vehicle dimension are analyzed.

  13. Online monitoring of boiler rapping gears. Specific targets; Online-Monitoring von Kesselklopfwerken. Konkrete Ergebnisse

    Energy Technology Data Exchange (ETDEWEB)

    Sigg, Alfred; Koller, Felix Bruno [Hitachi Zosen Inova AG, Zurich (Switzerland). Research and Development

    2013-03-01

    The boiler rapping gear from Hitachi Zosen Inova AG (Zurich, Switzerland) is in operation since September 2012. This boiler rapping gear shows that a continuous monitoring of the rapping gear function as well as the automatic induction of correcting measures within a running operation are possible inducing positive results. The three mechanisms of control are: measurement of the pressure loss and outlet temperature, monitoring of the thermal process in the vessel, verification of the functionality of the boiler rapping gear. The verification of the functionality of the boiler rapping gear is the early indicator for the necessary maintenance work for the prolongation of the boiler operating period. Operators of waste incinerators may generate more efficiency from their investment by using boiler rapping gears.

  14. F-106B airplane active control landing gear drop test performance

    Science.gov (United States)

    Howell, William E.; Mcgehee, John R.; Daugherty, Robert H.; Vogler, William A.

    1990-01-01

    Aircraft dynamic loads and vibrations resulting from landing impact and from runway and taxiway unevenness are recognized as significant factors in causing fatigue damage, dynamic stress on the airframe, crew and passenger discomfort, and reduction of the pilot's ability to control the aircraft during ground operations. One potential method for improving operational characteristics of aircraft on the ground is the application of active control technology to the landing gears to reduce ground loads applied to the airframe. An experimental investigation was conducted on series-hydraulic active control nose gear. The experiments involved testing the gear in both passive and active control modes. Results of this investigation show that a series-hydraulic active control gear is feasible and that such a gear is effective in reducing the loads transmitted by the gear to the airframe during ground operations.

  15. Flight investigation of piloting techniques and crosswind limitations using a research type crosswind landing gear

    Science.gov (United States)

    Fisher, B. D.; Deal, P. L.; Champine, R. A.; Patton, J. M., Jr.

    1979-01-01

    A research-type crosswind landing gear was tested in a flight program which used a light STOL transport in strong crosswind conditions. The research-type crosswind landing gear used enabled the airplane to land to crosswinds up to a magnitude of 25 to 30 knots. Three modes of landing-gear operation were investigated: preset, automatic, and castor (passive self-alignment). Actual test data and histograms are given for the 195 'visual flight rules' crosswind landings made.

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

    OpenAIRE

    Eigaard, O.R.; Bastardie, F.; Breen, M.; Hintzen, N.T.; Rijnsdorp, A.D.

    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 as logbook data. Here, we take a different approach starting from the gear itself (design and dimensions) to estimate the physical interactions with the seabed at the level of the individual fishin...

  17. Development of a Model Based Technique for Gear Diagnostics using the Wigner-Ville method

    Science.gov (United States)

    Choy, F.; Xu, A.; Polyshchuk, V.

    1997-01-01

    Imperfections in gear tooth geometry often result from errors in the manufacturing process or excessive material wear during operation. Such faults in the gear tooth geometry can result in large vibrations in the transmission system, and, in some cases, may lead to early failure of the gear transmission system. This report presents the study of the effects of imperfection in gear tooth geometry on the dynamic characteristics of a gear transmission system. The faults in the gear tooth geometry are modeled numerically as the deviation of the tooth profile from its original involute geometry. The changes in gear mesh stiffness due to various profile and pattern variations are evaluated numerically. The resulting changes in the mesh stiffness are incorporated into a computer code to simulate the dynamics of the gear transmission system. A parametric study is performed to examine the sensitivity of gear tooth geometry imperfections on the vibration of a gear transmission system. The parameters variations in this study consist of the magnitude of the imperfection, the pattern of the profile variation, and the total number of teeth affected. Numerical results from the dynamic simulations are examined in both the time and the frequency domains. A joint time-frequency analysis procedure using the Wigner-Ville Distribution is also introduced to identify the location of the damaged tooth from the vibration signature. Numerical simulations of the system dynamics with gear faults were compared to experimental results. An optimal tracker was introduced to quantify the level of damage in the gear mesh system. Conclusions are drawn from the results of this numerical study.

  18. Gearsketch: An Adaptive Drawing-Based Learning Environment for the Gears Domain

    Science.gov (United States)

    Leenaars, Frank A.; Joolingen, Wouter R.; Gijlers, Hannie; Bollen, Lars

    2014-01-01

    GearSketch is a learning environment for the gears domain, aimed at students in the final years of primary school. It is designed for use with a touchscreen device and is based on ideas from drawing-based learning and research on cognitive tutors. At the heart of GearSketch is a domain model that is used to transform learners' strokes into…

  19. Fault feature analysis of cracked gear based on LOD and analytical-FE method

    Science.gov (United States)

    Wu, Jiateng; Yang, Yu; Yang, Xingkai; Cheng, Junsheng

    2018-01-01

    At present, there are two main ideas for gear fault diagnosis. One is the model-based gear dynamic analysis; the other is signal-based gear vibration diagnosis. In this paper, a method for fault feature analysis of gear crack is presented, which combines the advantages of dynamic modeling and signal processing. Firstly, a new time-frequency analysis method called local oscillatory-characteristic decomposition (LOD) is proposed, which has the attractive feature of extracting fault characteristic efficiently and accurately. Secondly, an analytical-finite element (analytical-FE) method which is called assist-stress intensity factor (assist-SIF) gear contact model, is put forward to calculate the time-varying mesh stiffness (TVMS) under different crack states. Based on the dynamic model of the gear system with 6 degrees of freedom, the dynamic simulation response was obtained for different tooth crack depths. For the dynamic model, the corresponding relation between the characteristic parameters and the degree of the tooth crack is established under a specific condition. On the basis of the methods mentioned above, a novel gear tooth root crack diagnosis method which combines the LOD with the analytical-FE is proposed. Furthermore, empirical mode decomposition (EMD) and ensemble empirical mode decomposition (EEMD) are contrasted with the LOD by gear crack fault vibration signals. The analysis results indicate that the proposed method performs effectively and feasibility for the tooth crack stiffness calculation and the gear tooth crack fault diagnosis.

  20. Research on cutting vibration characteristics of face-milling involute gear

    Directory of Open Access Journals (Sweden)

    Chengzhe JIN

    2017-10-01

    Full Text Available Traditional machining methods, such as gear hobbing, gear shaping and gear milling, etc, are commonly used for cutting machining of gear tooth profile, which cannot meet huge machining demand of gears to a certain extent. This article proposes to utilize a face-milling machining method in involute gear machining, which can be used to reduce production cost effectively. Cutting vibration generated during cutting machining has a direct effect on the machining accuracy and machined surface quality of workpiece. Therefore, it is desiderated to perform in-depth research regarding this issue. ADAMS software was used to establish a rigid-flexible coupling virtual prototyping model of face-milling gear milling system and a cutting vibration system model. Cutting vibration analysis was performed for face-milling gear by adopting quick sine frequency sweep method, so that the frequency response characteristics of workpiece in three directions X, Y and Z and space were acquired. The research results will provide reference and theoretical foundation for actual application of face-milling gear machining technology.

  1. Generation of noncircular gears for variable motion of the crank-slider mechanism

    Science.gov (United States)

    Niculescu, M.; Andrei, L.; Cristescu, A.

    2016-08-01

    The paper proposes a modified kinematics for the crank-slider mechanism of a nails machine. The variable rotational motion of the driven gear allows to slow down the velocity of the slider in the head forming phase and increases the period for the forming forces to be applied, improving the quality of the final product. The noncircular gears are designed based on a hybrid function for the gear transmission ratio whose parameters enable multiple variations of the noncircular driven gears and crack-slider mechanism kinematics, respectively. The AutoCAD graphical and programming facilities are used (i) to analyse and optimize the slider-crank mechanism output functions, in correlation with the predefined noncircular gears transmission ratio, (ii) to generate the noncircular centrodes using the kinematics hypothesis, (iii) to generate the variable geometry of the gear teeth profiles, based on the rolling method, and (iv) to produce the gears solid virtual models. The study highlights the benefits/limits that the noncircular gears transmission ratio defining hybrid functions have on both crank-slider mechanism kinematics and gears geometry.

  2. Sizing Optimization and Strength Analysis for Spread-type Gear Reducers

    Directory of Open Access Journals (Sweden)

    Wei-Hsuan Hsu

    2014-08-01

    Full Text Available A reducer is now developed towards the trend of customization service and cost-saving. In this study, a sizing program for the reducer has been developed in order to replace the manual sizing process. We aim at the total center distance of the gear reducer for optimization to reduce gear volume and weight. Also, we checked constrains such as, tooth root bending, tooth contact strength, gear shaft endangered cross-section, bearing life, gear shaft deflection, and torsion angle deformation, etc., to obtain reliable drive strength. Comparisons of sizes and weights before and after optimization confirm that the purpose for reducing production cost is achieved.

  3. GEOMETRY MODELING OF GEAR AND CHAIN DRIVE WITH EVOLUTE PROFILE AND RESEARCH OF ITS CONTACT STRESS

    Directory of Open Access Journals (Sweden)

    Roman PROTASOV

    2017-05-01

    Full Text Available Evolute gearing is realized in a family of teeth profiles for gears and chain drives with convex-concave contact. The main criterion of loading capacity for gear is contact strength, for chain drive – tooth wear. Both indicators depend on the level of contact stress. Therefore, the aim of this work is to determine the contact stress in the evolute gearing. Calculations of contact stress are based on the Hertz formula and the finite element method. The analysis and comparison of results for different evolute profiles is carried out.

  4. THE IMPACT OF PROGRESSIVE GEAR GEOMETRY ON THE BRAKING DISTANCE LENGTH UNDER CHANGEABLE OPERATING CONDITIONS

    Directory of Open Access Journals (Sweden)

    Paweł Lonkwic

    2016-03-01

    Full Text Available This article presents independent tests results focused on the geometry impact of progressive gear used in a short distance transportation devices on the braking distance length both under changeable operating conditions as well as changeable loading. Variable operating conditions were obtained with the use of various lubricating agents. Five types of gears such as ASG100, PP16, PR2000, KB160 and a new solution CHP2000 were used for the tests. The tests were conducted with a free fall method application. The method gave a chance to evaluate reliability of tested gears systems and to compare the existing solutions with the proposed gear of CHP2000 type.

  5. Performance-based gear metrology kinematic, transmission, error computation and diagnosis

    CERN Document Server

    Mark, William D

    2012-01-01

    A mathematically rigorous explanation of how manufacturing deviations and damage on the working surfaces of gear teeth cause transmission-error contributions to vibration excitations Some gear-tooth working-surface manufacturing deviations of significant amplitude cause negligible vibration excitation and noise, yet others of minuscule amplitude are a source of significant vibration excitation and noise.   Presently available computer-numerically-controlled dedicated gear metrology equipment can measure such error patterns on a gear in a few hours in sufficient detail to enable

  6. Performance Investigation of a Full-Scale Hybrid Composite Bull Gear

    Science.gov (United States)

    LaBerge, Kelsen; Handschuh, Robert; Roberts, Gary; Thorp, Scott

    2016-01-01

    Hybrid composite gears have been investigated as a weight saving technology for rotorcraft transmissions. These gears differ from conventional steel gears in that the structural material between the shaft interface and the gear rim is replaced with a lightweight carbon fiber composite. The work discussed here is an extension of previous coupon level hybrid gear tests to a full-scale bull gear. The NASA Glenn Research Center High-Speed Helical Gear Rig was modified for this program allowing several hybrid gear web configurations to be tested while utilizing the same gear rim. Testing was performed on both a baseline (steel) web configuration and a hybrid (steel-composite)configuration. Vibration, orbit and temperature data were recorded and compared between configurations. Vibration levels did not differ greatly between the hybrid and steel configurations, nor did temperature differential between inlet and outlet. While orbit shape displayed differences between the hybrid and baseline configurations, the general overall amplitude was comparable. The hybrid configuration discussed here successfully ran at 3300 hp(2,460 kW), however, progressive growth of the orbit while running at this test condition discontinued the test. Researchers continue to search for the cause of this orbit shift.

  7. Analysis and Compensation for Gear Accuracy with Setting Error in Form Grinding

    Directory of Open Access Journals (Sweden)

    Chenggang Fang

    2015-01-01

    Full Text Available In the process of form grinding, gear setting error was the main factor that influenced the form grinding accuracy; we proposed an effective method to improve form grinding accuracy that corrected the error by controlling the machine operations. Based on establishing the geometry model of form grinding and representing the gear setting errors as homogeneous coordinate, tooth mathematic model was obtained and simplified under the gear setting error. Then, according to the gear standard of ISO1328-1: 1997 and the ANSI/AGMA 2015-1-A01: 2002, the relationship was investigated by changing the gear setting errors with respect to tooth profile deviation, helix deviation, and cumulative pitch deviation, respectively, under the condition of gear eccentricity error, gear inclination error, and gear resultant error. An error compensation method was proposed based on solving sensitivity coefficient matrix of setting error in a five-axis CNC form grinding machine; simulation and experimental results demonstrated that the method can effectively correct the gear setting error, as well as further improving the forming grinding accuracy.

  8. Advanced Gear Alloys for Ultra High Strength Applications

    Science.gov (United States)

    Shen, Tony; Krantz, Timothy; Sebastian, Jason

    2011-01-01

    Single tooth bending fatigue (STBF) test data of UHS Ferrium C61 and C64 alloys are presented in comparison with historical test data of conventional gear steels (9310 and Pyrowear 53) with comparable statistical analysis methods. Pitting and scoring tests of C61 and C64 are works in progress. Boeing statistical analysis of STBF test data for the four gear steels (C61, C64, 9310 and Pyrowear 53) indicates that the UHS grades exhibit increases in fatigue strength in the low cycle fatigue (LCF) regime. In the high cycle fatigue (HCF) regime, the UHS steels exhibit better mean fatigue strength endurance limit behavior (particularly as compared to Pyrowear 53). However, due to considerable scatter in the UHS test data, the anticipated overall benefits of the UHS grades in bending fatigue have not been fully demonstrated. Based on all the test data and on Boeing s analysis, C61 has been selected by Boeing as the gear steel for the final ERDS demonstrator test gearboxes. In terms of potential follow-up work, detailed physics-based, micromechanical analysis and modeling of the fatigue data would allow for a better understanding of the causes of the experimental scatter, and of the transition from high-stress LCF (surface-dominated) to low-stress HCF (subsurface-dominated) fatigue failure. Additional STBF test data and failure analysis work, particularly in the HCF regime and around the endurance limit stress, could allow for better statistical confidence and could reduce the observed effects of experimental test scatter. Finally, the need for further optimization of the residual compressive stress profiles of the UHS steels (resulting from carburization and peening) is noted, particularly for the case of the higher hardness C64 material.

  9. Compressibilities and viscosities of reference, vegetable, and synthetic gear lubricants

    DEFF Research Database (Denmark)

    Regueira Muñiz, Teresa; Lugo, Luis; Fernández, Josefa

    2014-01-01

    Nowadays, one of the primary choices of base oils for environmentally aware lubricants is vegetable oils. This is due to their good natural biodegradability and very low toxicity in combination with very good lubricity characteristics. The development of new vegetable-based lubricants requires...... values of six gear lubricants, two of them reference mineral oils and the other four developed biodegradable oils based in high oleic sunflower oil or in synthetic esters. It was found that all of the lubricants have both similar compressibilities and similar expansivities. Dowson and Higginson, Zhu...

  10. Identification of mine rescue equipment reduction gears technical condition

    Science.gov (United States)

    Gerike, B. L.; Klishin, V. I.; Kuzin, E. G.

    2017-09-01

    The article presents the reasons for adopting intelligent service of mine belt conveyer drives concerning evaluation of their technical condition based on the diagnostic techniques instead of regular preventative maintenance. The article reveals the diagnostic results of belt conveyer drive reduction gears condition taking into account the parameters of lubricating oil, vibration and temperature. Usage of a complex approach to evaluate technical conditions allows reliability of the forecast to be improved, which makes it possible not only to prevent accidental breakdowns and eliminate unscheduled downtime, but also to bring sufficient economic benefits through reduction of the term and scope of work during overhauls.

  11. Characterisation and Reduction of Aircraft Landing Gear Noise

    OpenAIRE

    NERI, ELEONORA

    2017-01-01

    APPROVED Aircraft noise has become an important concern in aviation design as it has a negative impact on the health of people living in the vicinity of airports. The total noise of an aircraft is generated by the engines and by the airframe as a result of unsteady flow over the aircraft structure, in particular high-lift devices, such as flaps and slats, and landing gears. While at take-off the airframe contribution to the overall noise is small and it is the engine (jet and fan) noise th...

  12. USE OF AUTODESK SIMULATION MULTIPHYSICS FOR RESEARCH OF TEMPERATURE FIELDS, STRESS AND DEFOMATION IN THE CONSTRUCTION OF GEAR PUMP

    Directory of Open Access Journals (Sweden)

    A. V. Puzanov

    2016-01-01

    Full Text Available Gear pumps are the most common type of hydraulic machines. They are used in various industries: oil and gas processing industry, in machine tools, mobile military, road-building and agricultural machinery. The need to ensure efficiency of hydraulic mobile applications in a wide climatic range requires increasing the accuracy of the calculation methods for the design of their elements. The results of temperature field modeling and caused them stress and strain. The results obtained allowed to justify the design and technological solutions, providing an increase of hydraulic performance at critical ambient temperatures.

  13. Optimization design of wind turbine drive train based on Matlab genetic algorithm toolbox

    Science.gov (United States)

    Li, R. N.; Liu, X.; Liu, S. J.

    2013-12-01

    In order to ensure the high efficiency of the whole flexible drive train of the front-end speed adjusting wind turbine, the working principle of the main part of the drive train is analyzed. As critical parameters, rotating speed ratios of three planetary gear trains are selected as the research subject. The mathematical model of the torque converter speed ratio is established based on these three critical variable quantity, and the effect of key parameters on the efficiency of hydraulic mechanical transmission is analyzed. Based on the torque balance and the energy balance, refer to hydraulic mechanical transmission characteristics, the transmission efficiency expression of the whole drive train is established. The fitness function and constraint functions are established respectively based on the drive train transmission efficiency and the torque converter rotating speed ratio range. And the optimization calculation is carried out by using MATLAB genetic algorithm toolbox. The optimization method and results provide an optimization program for exact match of wind turbine rotor, gearbox, hydraulic mechanical transmission, hydraulic torque converter and synchronous generator, ensure that the drive train work with a high efficiency, and give a reference for the selection of the torque converter and hydraulic mechanical transmission.

  14. Fiber Optic Strain Sensor for Planetary Gear Diagnostics

    Science.gov (United States)

    Kiddy, Jason S.; Lewicki, David G.; LaBerge, Kelsen E.; Ehinger, Ryan T.; Fetty, Jason

    2011-01-01

    This paper presents a new sensing approach for helicopter damage detection in the planetary stage of a helicopter transmission based on a fiber optic strain sensor array. Complete helicopter transmission damage detection has proven itself a difficult task due to the complex geometry of the planetary reduction stage. The crowded and complex nature of the gearbox interior does not allow for attachment of sensors within the rotating frame. Hence, traditional vibration-based diagnostics are instead based on measurements from externally mounted sensors, typically accelerometers, fixed to the gearbox exterior. However, this type of sensor is susceptible to a number of external disturbances that can corrupt the data, leading to false positives or missed detection of potentially catastrophic faults. Fiber optic strain sensors represent an appealing alternative to the accelerometer. Their small size and multiplexibility allows for potentially greater sensing resolution and accuracy, as well as redundancy, when employed as an array of sensors. The work presented in this paper is focused on the detection of gear damage in the planetary stage of a helicopter transmission using a fiber optic strain sensor band. The sensor band includes an array of 13 strain sensors, and is mounted on the ring gear of a Bell Helicopter OH-58C transmission. Data collected from the sensor array is compared to accelerometer data, and the damage detection results are presented

  15. Infant Positioning, Baby Gear Use, and Cranial Asymmetry.

    Science.gov (United States)

    Zachry, Anne H; Nolan, Vikki G; Hand, Sarah B; Klemm, Susan A

    2017-12-01

    Objectives This study aimed to identify predictors of cranial asymmetry. We hypothesize that among infants diagnosed with cranial asymmetry in the sampled region, there is an association between exposure to more time in baby gear and less awake time in prone and side-lying than in infants who do not present with this condition. Methods The study employed a cross sectional survey of caregivers of typically developing infants and infants diagnosed with cranial asymmetry. Results A mutivariable model reveals that caregivers of children who are diagnosed with cranial asymmetry report their children spending significantly less time in prone play than those children without a diagnosis of cranial asymmetry. Side-lying and time spent in baby gear did not attain statistical significance. Conclusions for Practice Occupational therapists, physical therapists, pediatricians, nurses and other health care professionals must provide parents with early education about the importance of varying positions and prone play in infancy and address fears and concerns that may serve as barriers to providing prone playtime.

  16. Rotational swashplate pulse continuously variable transmission based on helical gear axial meshing transmission

    Science.gov (United States)

    Sun, Jiandong; Fu, Wenyu; Lei, Hong; Tian, E.; Liu, Ziping

    2012-11-01

    The current research on pulse continuously variable transmission(CVT) is mainly focused on reducing the pulse degree and making pulse degrees a constant value. Current research mainly confined to find out new design parameters by using the method of optimization, and reduce the pulse degree of pulse CVT and its range of variation. But the fact is that the reduction of the pulse degree is not significant. This article presents a new structure of mechanical pulse CVT—the rotational swashplate pulse CVT with driven by helical gear axial meshing. This transmission is simple and compact in structure and low in pulsatile rate (it adopts 6 guide rods), and the pulsatile degree is irrelevant to the transmission ratio. Theoretically, pulsatile rate could be reduced to zero if appropriate curved surface of the swashplate is used. Compared with the connecting rod pulse CVT, the present structure uses helical gear mechanism as transmission part and it avoids unbalanced inertial force in the former model. This paper analyzes the principle of driving of this transmission, presents its mechanical structure, and discusses its motion characteristics. Experimental prototype of this type of CVT has been manufactured. Tests for the transmission efficiency(when the rotational speed of the output shaft is the maximum) and the angular velocity of the output shaft have been carried out, and data have been analyzed. The experimental results show that the speed of the output shaft for the experimental prototype is slightly lower than the theoretical value, and the transmission efficiency of the experimental prototype is about 70%. The pulse degree of the CVT discussed in this paper is less than the existing pulse CVT of other types, and it is irrelevant to the transmission ratio of the CVT. The research provides the new idea to the CVT study.

  17. ACCURACY RESEARCH OF THE DIAMETRICAL SIZES FORMING AT GEAR SHAPING BY STEPPED CUTTER

    Directory of Open Access Journals (Sweden)

    N. M. Rasulov

    2015-09-01

    Full Text Available The paper presents research results of forming accuracy for diametrical sizes at gear shaping with stepped cutter and the traditional method. Analysis of static technological dimensional pitch size chain of wheels being cut is performed. It was revealed that the most of transmission errors of the wheels, formed by the traditional gear-shaped cutter are caused by manufacturing and installation error of the cutter and result from the formation of each tooth of the wheel with a certain tool. This is not the case with gear shaping by step cutter since at that, the profiles of all gear teeth are formed by means of tooth profile mostly remote from the tool rotation axis. Analysis of occurrence of setting-up errors typical for the above gear shaping methods has been performed. At gear shaping with stepped cutter there are no setting-up error components. It was revealed that this fact causes the absence of errors in the tool position before its each double motion. The accuracy of diametrical sizes increases. Formation mechanism of tool installation errors and workpiece are also given and their analysis is presented. Findings in the field of gear shaping with stepped cutter comply with results of research carried out by the other authors in the field of traditional gear shaping.

  18. 46 CFR 31.10-16 - Inspection and certification of cargo gear-TB/ALL.

    Science.gov (United States)

    2010-10-01

    ... accessory gear; (3) Certification of the testing and examination of cranes, hoists, and their accessory gear; (4) Certification of the testing and examination of chains, rings, hooks, shackles, swivels, and... treatment of chains, rings, hooks, shackles, and swivels which require such treatment; and, (7...

  19. 76 FR 50180 - Proposed Information Collection; Comment Request; Northwest Region Gear Identification Requirements

    Science.gov (United States)

    2011-08-12

    ..., Department of Commerce, Room 6616, 14th and Constitution Avenue, NW., Washington, DC 20230 (or via the... concerning damage, loss, and civil proceedings. The regulations specify fishing gear must be marked with the.... The regulations further specify how the gear is to be marked (e.g., location and color). Law...

  20. 14 CFR 29.497 - Ground loading conditions: landing gear with tail wheels.

    Science.gov (United States)

    2010-01-01

    ... 14 Aeronautics and Space 1 2010-01-01 2010-01-01 false Ground loading conditions: landing gear with tail wheels. 29.497 Section 29.497 Aeronautics and Space FEDERAL AVIATION ADMINISTRATION... Requirements Ground Loads § 29.497 Ground loading conditions: landing gear with tail wheels. (a) General...

  1. 14 CFR 27.497 - Ground loading conditions: landing gear with tail wheels.

    Science.gov (United States)

    2010-01-01

    ... 14 Aeronautics and Space 1 2010-01-01 2010-01-01 false Ground loading conditions: landing gear with tail wheels. 27.497 Section 27.497 Aeronautics and Space FEDERAL AVIATION ADMINISTRATION... Requirements Ground Loads § 27.497 Ground loading conditions: landing gear with tail wheels. (a) General...

  2. Finish machining of hardened gears wheels using cubic boron nitride (CBN inserts

    Directory of Open Access Journals (Sweden)

    R. Talar

    2012-04-01

    Full Text Available The paper presents some results of investigation of finish machining of hardened bearing surfaces of cylindrical gear wheels. Finish machining has been performed with wedges of defined geometry made of CBN. The presented investigation results are related mainly to the wear processes of the cutting wedges. Additional results of quality examination of finish machined gear wheels have been presented, too.

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

    NARCIS (Netherlands)

    Eigaard, O.R.; Bastardie, F.; Breen, M.; Hintzen, N.T.; Rijnsdorp, A.D.

    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

  4. A general method to predict unbalance responses of geared rotor systems

    Science.gov (United States)

    Yang, Yi; Wang, Jiaying; Wang, Xurong; Dai, Yiping

    2016-10-01

    This paper concerns a general method to predict unbalance responses for a geared rotor system, which contains n shafts and at least n-1 spur and/or helical gear meshes. Finite element models of spur gear pairs and helical gear pairs are developed with arbitrary orientation angles, respectively. Then, a general method with a strict mathematical proof is proposed to calculate maximum axis radii of the unbalance response orbit for a geared rotor system. The proposed method is validated through three applications, i.e, a spur geared two-shaft rotor system, a spur geared multi-shaft rotor system and a helical geared multi-shaft rotor system. A classical modal synthesis is also employed as a comparison. Results show that proposed analytical solutions are consistent with the numerical results and have advantages over the modal synthesis. In addition, plenty of computer processing time can be saved with the proposed method. The method reported here may be of interest to engineers and educators attempting to handle the unbalance response analysis effectively and easily.

  5. Development and validation of a new reference cylindrical gear for pitch measurement

    DEFF Research Database (Denmark)

    Malberg, Maria Pia Sammartini; De Chiffre, Leonardo

    2000-01-01

    A new type of master gear, the Gauge Block Gear (GBG), was developed for the performance verification of coordinate measuring machines (CMMs), for the specific task of pitch and chordal tooth thickness measurement. Its main characteristic is the replacement of the teeth with gauge blocks, in order...... to achieve direct traceability of the chordal tooth thickness....

  6. 46 CFR 58.25-70 - Steering-gear control systems.

    Science.gov (United States)

    2010-10-01

    ... MACHINERY AND RELATED SYSTEMS Steering Gear § 58.25-70 Steering-gear control systems. (a) Each power-driven... arranged so that one operation of the switch's lever automatically supplies power to a complete system and... that not more than one control system and its associated power unit or units can be energized from the...

  7. 46 CFR 122.320 - Steering gear, controls, and communication system tests.

    Science.gov (United States)

    2010-10-01

    ... 46 Shipping 4 2010-10-01 2010-10-01 false Steering gear, controls, and communication system tests... communication system tests. The master of a vessel shall have examined and tested the steering gear, signaling whistle, propulsion controls, and communication systems of the vessel prior to getting underway for a...

  8. Diversity of selective and non-selective fishing gear and their impact ...

    African Journals Online (AJOL)

    user

    This survey was conducted in Al-Kalakla Fishery (KF) and Jabel Awlia Dam Fishery (JADF) in the White. Nile River, Khartoum state to identify the selective and non-selective fishing gear. The results showed the selective fishing gear represented by gill-nets and seine nets (beach nets) in both fisheries with clear variation in ...

  9. On the identification of the angular position of gears for the diagnostics of planetary gearboxes

    Science.gov (United States)

    D'Elia, G.; Mucchi, E.; Cocconcelli, M.

    2017-01-01

    Generally, in planetary gearbox diagnostics, vibration transducers are placed on the gearbox case near the ring gear. The relative angular position of the planet gears with respect to the transducer is a useful information for the evaluation of vibration signals related to planet/sun gears. This angular position is usually unknown, or it is known with a large tolerance causing serious difficulties in both gears and bearing diagnostics. In fact, noise and spurious component from healthy planets could overhang the informative content about incipient faults. The present work seeks to propose two alternative methods for the identification of the angular position of the planet gears with respect to the transducer. The first one is based on the study of how the power flows inside the Time Synchronous Average of the ring gear, whilst the second method is based on a modified statistical parameter such as the Crest Factor. The effectiveness of these methods is assessed on the basis of actual vibration signals acquired from a faulty planetary gearbox. The knowledge of the exact angular position of the planet gears allows the diagnostics of both gears and bearings, as proven by extensive experimental activities reported in the paper.

  10. THE APPLICATION OF UNIVERSAL CNC MACHINE TOOL FOR SPUR GEARS MANUFACTURING

    Directory of Open Access Journals (Sweden)

    Leszek Skoczylas

    2013-09-01

    Full Text Available The article introduces two variants of making spur gears by using universal CNC machine tools with universal shank cutter. The measurement of the chosen parameters of geometric structures of gear tooth surface were carried out as well as their comparison was made.

  11. 77 FR 5420 - Airworthiness Directives; Aeronautical Accessories Inc. High Landing Gear Aft Crosstube Assembly

    Science.gov (United States)

    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... aft crosstube assembly, removing paint and sealant, and fluorescent penetrant inspecting each aft...

  12. Diversity of selective and non-selective fishing gear and their impact ...

    African Journals Online (AJOL)

    This survey was conducted in Al-Kalakla Fishery (KF) and Jabel Awlia Dam Fishery (JADF) in the White Nile River, Khartoum state to identify the selective and non-selective fishing gear. The results showed the selective fishing gear represented by gill-nets and seine nets (beach nets) in both fisheries with clear variation in ...

  13. Optimal timing of harvest of two fish species with multiple gear types

    NARCIS (Netherlands)

    Hagendoorn, J.; Kruitwagen, S.; Heijman, W.J.M.

    2000-01-01

    In this paper a bioeconomic model is developed for a commercial fishery with multiple gear types in the case of two independent fish species. Where most bioeconomic fishery models focus on either multiple gear types or multiple species (mostly predator-prey relationships) this model combines both

  14. Bio-economic evaluation of implementing trawl fishing gear with different selectivity

    DEFF Research Database (Denmark)

    Kronbak, Lone Grønbæk; Nielsen, J. Rasmus; Jørgensen, Ole A.

    2009-01-01

    with a baseline. The results from the evaluation are indicators for the consequences on ecological and economic levels. The results show that implementation of different selective fishing gear in the Kattegat and Skagerrak mixed trawl fisheries generally implies a trade off over time between rebuilding the stocks...... and economic loss. Moreover, the analysis shows that implementation of more selective gear is not always beneficial....

  15. 29 CFR Appendix II to Part 1918 - Tables for Selected Miscellaneous Auxiliary Gear (Mandatory)

    Science.gov (United States)

    2010-07-01

    ... 29 Labor 7 2010-07-01 2010-07-01 false Tables for Selected Miscellaneous Auxiliary Gear (Mandatory) II Appendix II to Part 1918 Labor Regulations Relating to Labor (Continued) OCCUPATIONAL SAFETY AND.... 1918, App. II Appendix II to Part 1918—Tables for Selected Miscellaneous Auxiliary Gear (Mandatory...

  16. 78 FR 15009 - Extension of Deadline; Gaining Early Awareness and Readiness for Undergraduate Programs (GEAR UP...

    Science.gov (United States)

    2013-03-08

    ... From the Federal Register Online via the Government Publishing Office DEPARTMENT OF EDUCATION Extension of Deadline; Gaining Early Awareness and Readiness for Undergraduate Programs (GEAR UP)--College... Register (78 FR 4838) a notice inviting applications for the GEAR UP College Savings Account Research...

  17. The use of the virtual reality Helmet Samsung gear VR as interaction interface of a radioactive waste repository simulator

    Energy Technology Data Exchange (ETDEWEB)

    Santos, Julio A. dos; Mól, Antônio C. de A.; Santo, André C. Do E., E-mail: julio_andrade11@hotmail.com [Instituto de Engenharia Nuclear (IEN/CNEN-RJ), Rio de Janeiro, RJ (Brazil); Centro Universitário Carioca (UniCarioca), Rio de Janeiro, RJ (Brazil)

    2017-07-01

    Radioactive waste is all material resulting from human activity that contains elements that emit radiation that can generate risks to health and the environment. In this sense, they are very toxic also for those who perform the storage of radioactive waste in nuclear facilities. On the other hand, the virtual reality (VR) has been destined to the most diverse purposes, like simulations for educational systems, for military purposes as for diverse training. VR can be considered as the junction of three basic principles: immersion, interaction and involvement. Bases on these principles of VR, this work aimed to develop a simulator of a repository of nuclear tailings, for mobile computing, whose interaction interface will be through the Samsung Gear VR helmet. The simulator of the nuclear waste repository was developed in the unity 3D tool and the elements that make up the scenario in the 3D MAX program. In this work we tried to put virtual reality under scrutiny in conjunction with Gear VR, to help in the sensation of immersion, as well as, the possibility of interaction with joysticks. The purpose was to provide greater insight into the operating environment. (author)

  18. Research on Gear Shifting Process without Disengaging Clutch for a Parallel Hybrid Electric Vehicle Equipped with AMT

    Directory of Open Access Journals (Sweden)

    Hui-Long Yu

    2014-01-01

    Full Text Available Dynamic models of a single-shaft parallel hybrid electric vehicle (HEV equipped with automated mechanical transmission (AMT were described in different working stages during a gear shifting process without disengaging clutch. Parameters affecting the gear shifting time, components life, and gear shifting jerk in different transient states during a gear shifting process were deeply analyzed. The mathematical models considering the detailed synchronizer working process which can explain the gear shifting failure, long time gear shifting, and frequent synchronizer failure phenomenon in HEV were derived. Dynamic coordinated control strategy of the engine, motor, and actuators in different transient states considering the detailed working stages of synchronizer in a gear shifting process of a HEV is for the first time innovatively proposed according to the state of art references. Bench test and real road test results show that the proposed control strategy can improve the gear shifting quality in all its evaluation indexes significantly.

  19. Life test failure of harmonic gears in a Two-axis Gimbal for the Mars Reconnaissance Orbiter Spacecraft

    Science.gov (United States)

    Johnson, Michael R.; Gehling, Russ; Head, Ray

    2006-01-01

    This paper will present a process for increasing the stiffness of harmonic gear assemblies and recommend a maximum stiffness point that, if exceeded, compromises the reliability of the gear components for long life applications.

  20. Geared induction motor fault diagnosis by current, noise and vibration considering measurement environment

    Directory of Open Access Journals (Sweden)

    Ki-Seok Kim

    2017-01-01

    Full Text Available Lots of motors have been being used in industry. Therefore many studies have been carried out about the failure diagnosis of motors. In this paper, a diagnosis of gear fault connected to a motor shaft is studied. The fault diagnosis is executed through the comparison of normal gear and abnormal gear. In the abnormal gearbox, a tooth of the intermediate gear is damaged. The measured FFT data are compared with the normal data and analyzed for q-axis current, noise and vibration. Fault gear was found by comparing the FFT with normal FFT. From these, the difference between the normal and abnormal states can be seen by the frequency characteristic analysis for the current as well as noise and vibration.

  1. Optimizing Gear Shifting Strategy for Off-Road Vehicle with Dynamic Programming

    Directory of Open Access Journals (Sweden)

    Xinxin Zhao

    2014-01-01

    Full Text Available Gear shifting strategy of vehicle is important aid for the acquisition of dynamic performance and high economy. A dynamic programming (DP algorithm is used to optimize the gear shifting schedule for off-road vehicle by using an objective function that weighs fuel use and trip time. The optimization is accomplished through discrete dynamic programming and a trade-off between trip time and fuel consumption is analyzed. By using concave and convex surface road as road profile, an optimal gear shifting strategy is used to control the longitudinal behavior of the vehicle. Simulation results show that the trip time can be reduced by powerful gear shifting strategy and fuel consumption can achieve high economy with economical gear shifting strategy in different initial conditions and route cases.

  2. SIMULATION AND MODELING OF CYCLOID GEARS USED IN ORIENTATION MECHANISM OF ROBOTS

    Directory of Open Access Journals (Sweden)

    Lucia PASCALE

    2011-11-01

    Full Text Available Cycloid reducers compared with classical reducers have low axial and radial gauge, high transmission ratio, and a better reliability. Cycloid gearing roller, through its qualities, has an important role in modern mechanical transmissions. The difference between numbers of teeth of the cycloid gear roller can be equal to 1 (|z1 - z2|  1, without risk of interference, as a result, can be obtained big gear ratios in accordance with in lower overall dimensions, while the classic gear have the difference between teeth number min  z1 - z2  4. In this paper, the physical prototype of a new version of roller cycloid reducer is presented. Also one tries to test this variant of cycloid gear on a modern stand trial.

  3. Near-net shape manufacturing of miniature spur gears by wire spark erosion machining

    CERN Document Server

    Gupta, Kapil

    2016-01-01

    This work describes an experimental investigation with the aim to evaluate and establish wire spark erosion machining (WSEM) as a viable alternative for high quality miniature gear manufacturing. External spur type miniature brass (ASTM 858) gears with 12 teeth, 9.8 mm outside diameter and 5 mm face width were manufactured by WSEM. The research work was accomplished in four distinct experimental stages viz., preliminary, pilot, main and confirmation. The aim, scope and findings of each stage are progressively presented and discussed. In essence, the investigation found that it was possible to manufacture miniature gears to high quality by using WSEM. Gears up to DIN 5 quality with a good surface finish (1.2 µm average roughness) and satisfactory surface integrity were achieved. The results suggest that WSEM should be considered a viable alternative to conventional miniature gear manufacturing techniques and that in some instances it may even be superior. This work will prove useful to researchers and profess...

  4. Experimental Study on Vibration Reduction Characteristics of Gear Shafts Based on ISFD Installation Position

    Directory of Open Access Journals (Sweden)

    Kaihua Lu

    2017-01-01

    Full Text Available A novel type of integral squeeze film damper (ISFD is proposed to reduce and isolate vibration excitations of the gear system through bearing to the foundation. Four ISFD designs were tested experimentally with an open first-grade spur gear system. Vibration reduction characteristics were experimentally studied at different speeds for cases where ISFD elastic damping supports were simultaneously installed on the driving and driven shafts, installed on the driven shaft, or only installed on the driving shaft. Experimental results show that the ISFD elastic damping support can effectively reduce shock vibration of the gear system. Additionally, resonant modulation in gear shafts caused by meshing impact was significantly reduced. Different vibration amplitudes of gear shafts with ISFD installed only on driven or driving shafts were compared. Results indicated that vibration reduction is better when ISFD is only installed on the driven shaft than on the driving shaft.

  5. Thermal Behavior of Aerospace Spur Gears in Normal and Loss-of-Lubrication Conditions

    Science.gov (United States)

    Handschuh, Robert F.

    2015-01-01

    Testing of instrumented spur gears operating at aerospace rotorcraft conditions was conducted. The instrumented gears were operated in a normal and in a loss-of-lubrication environment. Thermocouples were utilized to measure the temperature at various locations on the test gears and a test utilized a full-field, high-speed infrared thermal imaging system. Data from thermocouples was recorded during all testing at 1 hertz. One test had the gears shrouded and a second test was run without the shrouds to permit the infrared thermal imaging system to take data during loss-of-lubrication operation. Both tests using instrumented spur gears were run in normal and loss-of-lubrication conditions. Also the result from four other loss-of-lubrication tests will be presented. In these tests two different torque levels were used while operating at the same rotational speed (10000 revolutions per minute).

  6. Spur Gear Tooth Pitting Propagation Assessment Using Model-based Analysis

    Science.gov (United States)

    Liang, Xi-Hui; Liu, Zhi-Liang; Pan, Jun; Zuo, Ming Jian

    2017-11-01

    Tooth pitting is a common failure mode of a gearbox. Many researchers investigated dynamic properties of a gearbox with localized pitting damage on a single gear tooth. The dynamic properties of a gearbox with pitting distributed over multiple teeth have rarely been investigated. In this paper, gear tooth pitting propagation to neighboring teeth is modeled and investigated for a pair of spur gears. Tooth pitting propagation effect on time-varying mesh stiffness, gearbox dynamics and vibration characteristics is studied and then fault symptoms are revealed. In addition, the influence of gear mesh damping and environmental noise on gearbox vibration properties is investigated. In the end, 114 statistical features are tested to estimate tooth pitting growth. Statistical features that are insensitive to gear mesh damping and environmental noise are recommended.

  7. Research on the gear operating state detection based on the fiber Bragg grating sensing technology

    Science.gov (United States)

    Liu, Yijun; Zhang, Wenying; Jin, Zhouyi; Liu, Jiapei; Li, Mingyue; Li, Xin; Geng, Biao; Dong, Bo

    2017-09-01

    With the development of people’s production and the accelerated growth of industrial demand, industrial manufacturers continue to improve the level of real-time detection of gear requirements. In order to improve the safety of mechanical equipment and to reduce the gear failure of the economic losses, the real-time monitoring of gear running technology is of a positive meaning. Based on the existing research results of gear dynamic detection, this paper proposes a fiber-optic grating sense of the gear operating state detection system. Stress tests were performed by varying the different load torques. The experimental results show that at the load of 10Nm and the rotating speed of 70r/min, the dedendum stress reached 130.4MPa. Compared with the theoretical value, the test error was 6.66%.

  8. Experimental Investigation of Shrouding on Meshed Spur Gear Windage Power Loss

    Science.gov (United States)

    Delgado, Irebert R.; Hurrell, Michael J.

    2017-01-01

    Windage power loss in high-speed gearboxes results in efficiency losses and increased heating due to drag on the gear teeth. Test results for meshed spur gear windage power loss are presented at ambient oil inlet temperatures, both with and without shrouding. The rate of windage power loss is observed to increase above a gear surface speed of 10,000 feet per minute (51 meters per second), similar to results presented in the literature. Shrouding is observed to become more effective above 15,000 feet per minute (76 meters per second), decreasing power loss by 10 percent at 25,000 feet per minute (127 meters per second). The need for gearbox oil drain slots limits the effectiveness of shrouding in reducing windage power loss. Windage power loss is observed to decrease with increasing gearbox temperatures and to increase with oil flow. Windage power losses for unshrouded meshed spur gears are 7 times greater than losses determined from unshrouded single spur gear tests. A 6- to 12-times increase in windage power loss is observed in the shrouded meshed spur gear data compared with shrouded single spur gear data. Based on this preliminary study, additional research is suggested to determine the effect of oil drain slot configurations, axial and radial shroud clearances, and higher gear surface speeds on windage power loss. Additional work is also suggested to determine the sensitivity of windage power loss to oil temperature and oil flow. Windage power loss for meshed spur gears tested in both the shrouded and unshrouded configurations is shown to be more than double versus windage power loss for the same spur gears run individually in the same shroud configurations. Further study of the physical processes behind these results is needed to optimize gearbox shrouds for minimum windage power loss.

  9. When skeletons are geared for speed: the morphology, biomechanics, and energetics of rapid animal motion.

    Science.gov (United States)

    McHenry, Matthew J

    2012-11-01

    A skeleton amplifies the minute contractions of muscles to animate the body of an animal. The degree that a muscular contraction displaces an appendage is determined by the gearing provided by the joints of a skeleton. Species that move rapidly commonly possess joints with relatively high gears that produce a large output displacement. However, the speed of an appendage can depend on dynamics that obscure how this motion is influenced by the skeleton. The aim of this review is to resolve mechanical principles that govern the relationship between the gearing and speed of skeletal joints. Forward dynamic models of three rapid force-transmission systems were examined with simulations that varied the gearing of a joint. The leg of a locust, the raptorial appendage of a mantis shrimp, and the jaw of a toad are all driven by the conversion of stored elastic energy into kinetic energy. A locust achieves this conversion with high efficiency when it kicks and thereby applies nearly all stored energy into fast movement. This conversion is unaffected by differences in the leverage of the knee joint, as demonstrated by a maximum kicking speed that was found to be independent of gearing. In contrast, the mantis shrimp creates drag as it strikes toward a prey and thereby loses energy. As a consequence, high gears displace the raptorial appendage relatively far and yield slower motion than do low gears. The muscle that opens a toad's jaw also dissipates energy during ballistic capture of prey. This loss of energy is reduced when jaw opening occurs from the slower muscle contraction produced by a high gear within the jaw. Therefore, the speed of these lever systems is dictated by how gearing affects the efficiency of the conversion of potential energy into kinetic energy. In this way, the energetics of force transmission mediate the relationship between the gearing of a skeletal joint and the maximum speed of its motion.

  10. Effect of gear ratio on peak power and time to peak power in BMX cyclists.

    Science.gov (United States)

    Rylands, Lee P; Roberts, Simon J; Hurst, Howard T

    2017-03-01

    The aim of this study was to ascertain if gear ratio selection would have an effect on peak power and time to peak power production in elite Bicycle Motocross (BMX) cyclists. Eight male elite BMX riders volunteered for the study. Each rider performed three, 10-s maximal sprints on an Olympic standard indoor BMX track. The riders' bicycles were fitted with a portable SRM power meter. Each rider performed the three sprints using gear ratios of 41/16, 43/16 and 45/16 tooth. The results from the 41/16 and 45/16 gear ratios were compared to the current standard 43/16 gear ratio. Statistically, significant differences were found between the gear ratios for peak power (F(2,14) = 6.448; p = .010) and peak torque (F(2,14) = 4.777; p = .026), but no significant difference was found for time to peak power (F(2,14) = 0.200; p = .821). When comparing gear ratios, the results showed a 45/16 gear ratio elicited the highest peak power,1658 ± 221 W, compared to 1436 ± 129 W and 1380 ± 56 W, for the 43/16 and 41/16 ratios, respectively. The time to peak power showed a 41/16 tooth gear ratio attained peak power in -0.01 s and a 45/16 in 0.22 s compared to the 43/16. The findings of this study suggest that gear ratio choice has a significant effect on peak power production, though time to peak power output is not significantly affected. Therefore, selecting a higher gear ratio results in riders attaining higher power outputs without reducing their start time.

  11. 33 CFR 150.505 - When must the operator service and examine lifeboat and rescue boat release gear?

    Science.gov (United States)

    2010-07-01

    ... and examine lifeboat and rescue boat release gear? 150.505 Section 150.505 Navigation and Navigable... and examine lifeboat and rescue boat release gear? (a) The operator must service lifeboat and rescue boat release gear at intervals recommended in the manufacturer's instructions under § 150.502(a), or...

  12. 50 CFR 648.80 - NE Multispecies regulated mesh areas and restrictions on gear and methods of fishing.

    Science.gov (United States)

    2010-10-01

    ...) The ground gear must all be bare wire not larger than 1/2-inch (1.2-cm) for the top leg, not larger... restrictions on gear and methods of fishing. 648.80 Section 648.80 Wildlife and Fisheries FISHERY CONSERVATION... § 648.80 NE Multispecies regulated mesh areas and restrictions on gear and methods of fishing. Except as...

  13. 77 FR 67580 - Fisheries of the Exclusive Economic Zone Off Alaska; Pacific Cod by Vessels Using Jig Gear in the...

    Science.gov (United States)

    2012-11-13

    ... Economic Zone Off Alaska; Pacific Cod by Vessels Using Jig Gear in the Central Regulatory Area of the Gulf... directed fishing for Pacific cod by vessels using jig gear in the Central Regulatory Area of the Gulf of...) apportioned to vessels using jig gear in the Central Regulatory Area of the GOA. DATES: Effective 1200 hrs...

  14. 77 FR 6683 - Fisheries of the Exclusive Economic Zone Off Alaska; Pacific Cod by Vessels Using Pot Gear in the...

    Science.gov (United States)

    2012-02-09

    ... Economic Zone Off Alaska; Pacific Cod by Vessels Using Pot Gear in the Western Regulatory Area of the Gulf... for Pacific cod by vessels using pot gear in the Western Regulatory Area of the Gulf of Alaska (GOA... allowable catch apportioned to vessels using pot gear in the Western Regulatory Area of the GOA. DATES...

  15. 78 FR 10102 - Fisheries of the Exclusive Economic Zone Off Alaska; Pacific Cod by Vessels Using Pot Gear in the...

    Science.gov (United States)

    2013-02-13

    ... Economic Zone Off Alaska; Pacific Cod by Vessels Using Pot Gear in the Central Regulatory Area of the Gulf... for Pacific cod by vessels using pot gear in the Central Regulatory Area of the Gulf of Alaska (GOA... allowable catch apportioned to vessels using pot gear in the Central Regulatory Area of the GOA. DATES...

  16. 77 FR 8177 - Fisheries of the Exclusive Economic Zone Off Alaska; Pacific Cod by Vessels Using Pot Gear in the...

    Science.gov (United States)

    2012-02-14

    ... Economic Zone Off Alaska; Pacific Cod by Vessels Using Pot Gear in the Central Regulatory Area of the Gulf... for Pacific cod by vessels using pot gear in the Central Regulatory Area of the Gulf of Alaska (GOA... allowable catch apportioned to vessels using pot gear in the Central Regulatory Area of the GOA. DATES...

  17. 78 FR 7280 - Fisheries of the Exclusive Economic Zone Off Alaska; Pacific Cod by Vessels Using Pot Gear in the...

    Science.gov (United States)

    2013-02-01

    ... Economic Zone Off Alaska; Pacific Cod by Vessels Using Pot Gear in the Western Regulatory Area of the Gulf... for Pacific cod by vessels using pot gear in the Western Regulatory Area of the Gulf of Alaska (GOA... allowable catch apportioned to vessels using pot gear in the Western Regulatory Area of the GOA. DATES...

  18. 77 FR 62464 - Fisheries of the Exclusive Economic Zone Off Alaska; Pacific Cod by Vessels Using Pot Gear in the...

    Science.gov (United States)

    2012-10-15

    ... Economic Zone Off Alaska; Pacific Cod by Vessels Using Pot Gear in the Central Regulatory Area of the Gulf... for Pacific cod by vessels using pot gear in the Central Regulatory Area of the Gulf of Alaska (GOA... vessels using pot gear in the Central Regulatory Area of the GOA. DATES: Effective 1200 hrs, Alaska local...

  19. 77 FR 14305 - Fisheries of the Exclusive Economic Zone Off Alaska; Pacific Cod by Vessels Using Jig Gear in the...

    Science.gov (United States)

    2012-03-09

    ... Economic Zone Off Alaska; Pacific Cod by Vessels Using Jig Gear in the Central Regulatory Area of the Gulf... for Pacific cod by vessels using jig gear in the Central Regulatory Area of the Gulf of Alaska (GOA... allowable catch apportioned to vessels using jig gear in the Central Regulatory Area of the GOA. DATES...

  20. 77 FR 65640 - Fisheries of the Exclusive Economic Zone Off Alaska; Pacific Cod by Vessels Using Pot Gear in the...

    Science.gov (United States)

    2012-10-30

    ... Economic Zone Off Alaska; Pacific Cod by Vessels Using Pot Gear in the Central Regulatory Area of the Gulf... directed fishing for Pacific cod by vessels using pot gear in the Central Regulatory Area of the Gulf of...) apportioned to vessels using pot gear in the Central Regulatory Area of the GOA. DATES: Effective 1200 hrs...