WorldWideScience

Sample records for two-axis track rollers

  1. Two-axis solar tracking accomplished through small lateral translations.

    Science.gov (United States)

    Hallas, Justin M; Baker, Katherine A; Karp, Jason H; Tremblay, Eric J; Ford, Joseph E

    2012-09-01

    High-concentration solar-power optics require precise two-axis tracking. The planar micro-optic solar concentrator uses a lenslet array over a planar waveguide with small reflective facets at the focal point of each lenslet to couple incident light into the waveguide. The concentrator can use conventional tracking, tilting the entire assembly, but the system geometry also allows tracking by small lateral translation of the lenslet relative to the waveguide. Here, we experimentally demonstrate such microtracking with the existing concentrator optics and present optimized optical designs for systems with higher efficiency and angle range.

  2. A Two-Axis Goniometric Sensor for Tracking Finger Motion.

    Science.gov (United States)

    Wang, Lefan; Meydan, Turgut; Williams, Paul Ieuan

    2017-04-05

    The study of finger kinematics has developed into an important research area. Various hand tracking systems are currently available; however, they all have limited functionality. Generally, the most commonly adopted sensors are limited to measurements with one degree of freedom, i.e., flexion/extension of fingers. More advanced measurements including finger abduction, adduction, and circumduction are much more difficult to achieve. To overcome these limitations, we propose a two-axis 3D printed optical sensor with a compact configuration for tracking finger motion. Based on Malus' law, this sensor detects the angular changes by analyzing the attenuation of light transmitted through polarizing film. The sensor consists of two orthogonal axes each containing two pathways. The two readings from each axis are fused using a weighted average approach, enabling a measurement range up to 180 ∘ and an improvement in sensitivity. The sensor demonstrates high accuracy (±0.3 ∘ ), high repeatability, and low hysteresis error. Attaching the sensor to the index finger's metacarpophalangeal joint, real-time movements consisting of flexion/extension, abduction/adduction and circumduction have been successfully recorded. The proposed two-axis sensor has demonstrated its capability for measuring finger movements with two degrees of freedom and can be potentially used to monitor other types of body motion.

  3. Research on electromechanical resonance of two-axis tracking system

    Science.gov (United States)

    Zhao, Zhi-ming; Xue, Ying-jie; Zeng, Shu-qin; Li, Zhi-guo

    2017-02-01

    The multi-axes synchronous system about the spatial two-axis turntable is the key equipment for semi-physical simulation and test in aerospace. In this paper, the whole structure design of the turntable is created by using Solidworks, then putting the three-dimensional solid model into ANSYS to build the finite element model. The software ANSYS is used to do the simulation about the static and dynamic analysis of two-axis turntable. Based on the modal analysis, we can forecast the inherent frequencies and the mode of vibration during the launch conditions which is very important to the design and safety of the structure.

  4. Two-axis tracking using translation stages for a lens-to-channel waveguide solar concentrator.

    Science.gov (United States)

    Liu, Yuxiao; Huang, Ran; Madsen, Christi K

    2014-10-20

    A two-axis tracking scheme designed for concentration realized by a single-axis mechanical tracker and a translation stage is discussed. The translation stage is used for adjusting positions for seasonal sun movement. It has two-dimensional x-y tracking instead of horizontal movement x-only. This tracking method is compatible with planar waveguide solar concentrators. A prototype system with 50x concentration shows >75% optical efficiency throughout the year in simulation and >65% efficiency experimentally. This efficiency can be further improved by the use of anti-reflection layers and a larger waveguide refractive index.

  5. Solar Tracking Systems and A Two-Axis Active Prototype With Stepwise Movement

    OpenAIRE

    Gökhan ORAL; Osman N. UÇAN

    2014-01-01

    In this work, criteria for a two-axis solar tracking system that provides a higher voltage and power output than a fixed solar panel, are determined and a prototype is realized with stepwise movement. From that point on, to design a practical solar tracker, extensive research studies were conducted which resulted in determination of optimal techniques and components. As a result, by using a small scale solar panel, servo motors as drive elements, Arduino processor as the controller, and a wir...

  6. Development of Intelligent Fuzzy Controller for a Two-Axis Solar Tracking System

    Directory of Open Access Journals (Sweden)

    Cong-Hui Huang

    2016-05-01

    Full Text Available This paper proposes the development of a two-axis sun tracking solar energy system using fuzzy logic as intelligent quality policy. To achieve maximum efficiency for solar panels, it is necessary to follow the sun’s path in the sky. Therefore, the architecture for the two-axis sun tracking solar energy system uses software to control the hardware. The hardware comprises (i solar cells; (ii lead-acid batteries; (iii a gear box; (iv a stepping motor; and (v a light detection circuit, while the software comprises (i a detection system; (ii a fuzzy tracking controller; and (iii a database system. A fuzzy logic controller is designed as the software architecture of the system to decide the timing for tracking the sun. The nearest position that results in receiving direct sunlight is obtained from the database. Our system is fully automatic in a changing environment and takes into account meteorological changes and the effects of the external environment arising from a malfunction. This approach reduces the number of starting motors and results in smaller energy loss in cloudy, cloud mask, or unstable weather conditions.

  7. Two-axis Beam Steering Mirror Control system for Precision Pointing and Tracking Applications

    Energy Technology Data Exchange (ETDEWEB)

    Ulander, Klaus [California Polytechnic State Univ. (CalPoly), San Luis Obispo, CA (United States)

    2006-01-01

    Precision pointing and tracking of laser beams is critical in numerous military and industrial applications. This is particularly true for systems requiring atmospheric beam propagation. Such systems are plagued by environmental influences which cause the optical signal to break up and wander. Example applications include laser communications, precision targeting, active imaging, chemical remote sensing, and laser vibrometry. The goal of this project is to build a beam steering system using a two-axis mirror to maintain precise pointing control. Ultimately, position control to 0.08% accuracy (40 {micro}rad) with a bandwidth of 200 Hz is desired. The work described encompasses evaluation of the instrumentation system and the subsequent design and implementation of an analog electronic controller for a two-axis mirror used to steer the beam. The controller operates over a wide temperature range, through multiple mirror resonances, and is independent of specific mirrors. The design was built and successfully fielded in a Lawrence Livermore National Laboratory free-space optics experiment. All measurements and performance parameters are derived from measurements made on actual hardware that was built and field tested. In some cases, specific design details have been omitted that involve proprietary information pertaining to Lawrence Livermore National Laboratory patent positions and claims. These omissions in no way impact the general validity of the work or concepts presented in this thesis.

  8. Pneu-Scan - A novel, lightweight two-axis telemetry tracking system

    Science.gov (United States)

    Sullivan, A.

    The development of Pneu-Scan, a conically scanning tracking antenna feed for telemetry applications, is described. Pneu-Scan has the advantage of being pneumatically driven, thereby eliminating the need for a heavy electric drive motor. Air from the dehydrator/pressurizer system is used to drive the Pneu-Scan pedestal at a scan speed which is proportional to the continuously varying pressure. The S-band tracking feed of the Pneu-Scan is less than five inches in diameter and is considerably lighter than single-channel monopulse (SCM) feeds. Aperture blocking of Pneu-Scan is more than two times smaller than conventional SCM designs. The antenna reflector of the Pneu-Scan system is a lightweight 5-foot graphite-epoxy parabolical reflector positioned by an elevator-over-azimuth pedestal. The elevation assembly is surrounded by an inflatable rotodome which rotates with azimuth. The rotating sphere was designed to have a minimum wind-induced torque, thereby minimizing the required drive power. The weight of the entire system is less than 135 pounds. The principle characteristics of the Pneu-Scan system are summarized in a table.

  9. Seguidor Solar de Dos Ejes para un Horno Solar Two-Axis Sun Tracking System for a Solar Furnace

    Directory of Open Access Journals (Sweden)

    Gabriel Villeda

    2011-01-01

    Full Text Available Se presenta el diseño y fabricación de un seguidor solar de dos ejes (rotación-elevación, el cual controla un helióstato de un horno solar para la cocción de tabiques de arcilla. El sistema trabaja con motores controlados desde una computadora personal. El algoritmo para el seguidor solar se desarrolló en un lenguaje de programación visual, calcula los ángulos de seguimiento primario y secundario del helióstato y los despliega en una pantalla. El microcontrolador está programado para controlar el funcionamiento de los motores a pasos, los cuales mueven el helióstato del horno solar. El seguimiento primario y secundario es el mismo para los equinoccios, mientras que para los solsticios son diferentes debido a que durante el verano en el hemisferio norte existe mayor altura solar que en invierno. El seguidor solar permite una captación más eficiente de la radiación solar debido a que sigue minuto a minuto el movimiento aparente del Sol.The design and manufacture of a two-axis sun tracking system (rotation-elevation, which controls a heliostat of a solar furnace for clay brick firing is presented. The system works with motors controlled through a personal computen The algorithm for the sun tracking system was developed in a visual programming language, calculates the primary and secondary tracking angles of the heliostat and shows them in a screen. The microcontroller is programmed to control the step driver engines, which move the heliostat of the solar furnace. The primary and secondary tracking is the same for the equinoxes, whereas for the solstices are different because the solar altitude is greater in summer than in winter in the northern hemisphere. The sun tracking system permits a more efficient capture of the solar radiation since it continuously follows the apparent movement of the Sun.

  10. Double lens collimator solar feedback sensor and master slave configuration: Development of compact and low cost two axis solar tracking system for CPV applications

    KAUST Repository

    Burhan, Muhammad

    2016-08-31

    The conventional CPV systems, as big unit design, are only suitable to be installed in the open regions, like desert areas. This gigantic system design restricts their use on the rooftop of commercial and residential buildings, unlike the conventional PV systems. This paper proposes a compact but highly accurate and cheap two axis solar tracking system, designed for CPV system field operation. The proposed system is designed and verified for tracking accuracy requirement of 0.3 degrees, and has maximum capability of as high as 0.1 degrees tracking accuracy. High tracking accuracy is ensured using in-house built double lens collimator solar feedback sensor, within a fraction of the cost of commercial solar tracking sensors. A hybrid tracking algorithm is developed in C-programming using astronomical and optical solar tracking methods. As compact CPV system design demands larger number of tracking units, for same power capacity of system. Therefore, a master slave control configuration is also proposed for the CPV field operation. Only master tracker will be equipped with the expensive tracking devices, while the required tracking information will be sent to all of the slave trackers using wireless communication through ZigBee devices. With detailed optical design, simulation and control strategy, a prototype of the proposed CPV tracking system is developed, experimentally investigated and verified for tracking accuracy for outdoor operation at the rooftop. (C) 2016 Elsevier Ltd. All rights reserved.

  11. Designing and Simulation of a Two-Axis Solar Tracking System by Exact Relations of Solar Angles

    Directory of Open Access Journals (Sweden)

    Faezeh Esmaili Ranjbar

    2013-01-01

    Full Text Available In this study, a system has been designed and simulated to track sunlight, which identifies sun location based on the exact relations of solar angles and without any optical sensor. In fact the relations which have been used in this study are far more accurate compared to similar cases, because of using the "equation of time" and reducing the tracking time of every 15 minutes. In this system, an economical micro-controller has been used to generate the necessary orders to control system and two stepper motors for powering solar array. By adding a real-time clock IC (RTC to angle differentiation circuit, dynamic plane has improved.

  12. The Comfortable Roller Coaster--on the Shape of Tracks with a Constant Normal Force

    Science.gov (United States)

    Nordmark, Arne B.; Essen, Hanno

    2010-01-01

    A particle that moves along a smooth track in a vertical plane is influenced by two forces: gravity and normal force. The force experienced by roller coaster riders is the normal force, so a natural question to ask is, what shape of the track gives a normal force of constant magnitude? Here we solve this problem. It turns out that the solution is…

  13. The Comfortable Roller Coaster--on the Shape of Tracks with a Constant Normal Force

    Science.gov (United States)

    Nordmark, Arne B.; Essen, Hanno

    2010-01-01

    A particle that moves along a smooth track in a vertical plane is influenced by two forces: gravity and normal force. The force experienced by roller coaster riders is the normal force, so a natural question to ask is, what shape of the track gives a normal force of constant magnitude? Here we solve this problem. It turns out that the solution is…

  14. Genetic Algorithm Based PID Controller Design for a Precise Tracking of Two-Axis Piezoelectric Micropositioning Stage

    Directory of Open Access Journals (Sweden)

    Yasir Khudhair Abbas

    2012-01-01

    Full Text Available In this paper, an intelligent tracking control system of both single- and double-axis Piezoelectric Micropositioner stage is designed using Genetic Algorithms (GAs method for the optimal Proportional-Integral-Derivative (PID controller tuning parameters. The (GA-based PID control design approach is a methodology to tune a (PID controller in an optimal control sense with respect to specified objective function. By using the (GA-based PID control approach, the high-performance trajectory tracking responses of the Piezoelectric Micropositioner stage can be obtained. The (GA code was built and the simulation results were obtained using MATLAB environment. The Piezoelectric Micropositioner simulation model with the (GA-based PID control is illustrated to show the validity of the proposed control method for practical applications, such as scanning microscopy.

  15. Design of two-axis tracking system of solar streetlamp%太阳能路灯双轴跟踪系统设计

    Institute of Scientific and Technical Information of China (English)

    刘日平; 任天平; 吕寻浩

    2014-01-01

    针对当前太阳能路灯转换效率低的弊端,介绍了一种太阳能路灯双轴跟踪系统,通过实时检测光强的变化驱动执行机构,保证太阳能电池板始终垂直于太阳光线,从而提高太阳能利用效率。实验表明,太阳能电池板在双轴跟踪情况下,发电量要比最佳角度固定安装提高34%。%Due to the low conversion efficiency of solar tracker, the paper introduces a kind of two-axis tracking system. It tests the change of light and droved actuator on time to make sure the solar panels and sun light meet each other at right angles to increase the conversion efficiency of solar tracker. According to experiments , the two-axis tracker can increase the power output by 34 percent.

  16. The comfortable roller coaster-on the shape of tracks with a constant normal force

    Energy Technology Data Exchange (ETDEWEB)

    Nordmark, Arne B; Essen, Hanno, E-mail: hanno@mech.kth.s [Department of Mechanics, KTH, 100 44 Stockholm (Sweden)

    2010-11-15

    A particle that moves along a smooth track in a vertical plane is influenced by two forces: gravity and normal force. The force experienced by roller coaster riders is the normal force, so a natural question to ask is, what shape of the track gives a normal force of constant magnitude? Here we solve this problem. It turns out that the solution is related to the Kepler problem; the trajectories in velocity space are conic sections.

  17. The comfortable roller coaster -- on the shape of tracks with constant normal force

    CERN Document Server

    Nordmark, Arne B

    2010-01-01

    A particle that moves along a smooth track in a vertical plane is influenced by two forces: gravity and normal force. The force experienced by roller coaster riders is the normal force, so a natural question to ask is: what shape of the track gives a normal force of constant magnitude? Here we solve this problem. It turns out that the solution is related to the Kepler problem; the trajectories in velocity space are conic sections.

  18. Dragline roller track improvement. Volume I. Evaluation of low hardness dragline track materials in rolling contact. Final report, September 30, 1976-July 30, 1980

    Energy Technology Data Exchange (ETDEWEB)

    Dunfee, J.; Leonard, L.; Rumbarger, J.

    1980-01-01

    The Franklin Research Center (FRC), a Division of the Franklin Institute, was contracted by the Bureau of Mines to improve walking dragline roller tracks. The contract was subsequently transferred to the Department of Energy. The period from September 1977 to September 1978 covered laboratory rolling contact rig tests to evaluate typical low hardness dragline track materials. The results of this work are covered by DOE/ET/9121-1 Final Report, Volume I. The period from September 1978 to July 1980 covered field measurements of dragline roller circle loadings. The results of this work are covered by DOE/ET/9121-2 Final Report, Volume II. The laboratory rolling contact rig test results indicate that forged vacuum degassed air melt steel materials are recommended over air-melt cast materials for rollers and tracks. The steels tested exhibited good freedom from sensitivity to stress raisers like brinell marks and small holes or discontinuities (Volume I). The largest unknown in a recommended method for life testing roller tracks is the condition of the upper rotating frame structure and the lower tub supporting structure.

  19. Two-axis angular effector

    Energy Technology Data Exchange (ETDEWEB)

    Vaughn, Mark R. (Albuquerque, NM); Robinett, III, Rush D. (Tijeras, NM); Phelan, John R. (Albuquerque, NM); Van Zuiden, Don M. (Albuquerque, NM)

    1997-01-21

    A new class of coplanar two-axis angular effectors. These effectors combine a two-axis rotational joint analogous to a Cardan joint with linear actuators in a manner to produce a wider range of rotational motion about both axes defined by the joint. This new class of effectors also allows design of robotic manipulators having very high strength and efficiency. These effectors are particularly suited for remote operation in unknown surroundings, because of their extraordinary versatility. An immediate application is to the problems which arise in nuclear waste remediation.

  20. Two-axis angular effector

    Energy Technology Data Exchange (ETDEWEB)

    Vaughn, M.R.; Robinett, R.D. III; Phelan, J.R.; Zuiden, D.M. Van

    1997-01-21

    A new class of coplanar two-axis angular effectors is described. These effectors combine a two-axis rotational joint analogous to a Cardan joint with linear actuators in a manner to produce a wider range of rotational motion about both axes defined by the joint. This new class of effectors also allows design of robotic manipulators having very high strength and efficiency. These effectors are particularly suited for remote operation in unknown surroundings, because of their extraordinary versatility. An immediate application is to the problems which arise in nuclear waste remediation. 11 figs.

  1. Roller coasters, g forces, and brain trauma: on the wrong track?

    Science.gov (United States)

    Smith, Douglas H; Meaney, David F

    2002-10-01

    There has been enormous attention in the general press on the possibility that high G force roller coasters are inducing brain injury in riders. Armed with a handful of anecdotal case reports of brain injuries, the U.S. Congress has recently proposed legislation to regulate the level of G forces of roller coasters. However, high G forces are well tolerated during many activities and, therefore, are a poor measure for the risk of brain injury. Rather, accelerations of the head that can be caused by G forces are the key to producing injury. To determine the extent of head accelerations during roller coaster rides, we acquired G force data from three popular high G roller coasters. We used the highest recorded G forces in a simple mathematical model of head rotational acceleration, with the head rigidly pivoting from the base of the skull at a radius representing typical men and women. With this model, we calculated peak head rotational accelerations in three directions. Even for a conservative worst-case scenario, we found that the highest estimated peak head accelerations induced by roller coasters were far below conventional levels that are predicted for head injuries. Accordingly, our findings do not support the contention that current roller coaster rides produce high enough forces to mechanically deform and injure the brain.

  2. Roller Coasters!

    Science.gov (United States)

    Ansberry, Karen; Morgan, Emily

    2008-01-01

    Students of all ages are fascinated by the ups, downs, loops, and twists of roller coaster rides! What they may not realize is that there is a lot of science involved in making a roller coaster work. This month's column puts students in the shoes of a roller coaster designer as they work in teams to create their own roller coasters. (Contains 1…

  3. Roller Coasters!

    Science.gov (United States)

    Ansberry, Karen; Morgan, Emily

    2008-01-01

    Students of all ages are fascinated by the ups, downs, loops, and twists of roller coaster rides! What they may not realize is that there is a lot of science involved in making a roller coaster work. This month's column puts students in the shoes of a roller coaster designer as they work in teams to create their own roller coasters. (Contains 1…

  4. Roller-gear drives for robotic manipulators design, fabrication and test

    Science.gov (United States)

    Anderson, William J.; Shipitalo, William

    1991-09-01

    Two single axis planetary roller-gear drives and a two axis roller-gear drive with dual inputs were designed for use as robotic transmissions. Each of the single axis drives is a two planet row, four planet arrangement with spur gears and compressively loaded cylindrical rollers acting in parallel. The two axis drive employs bevel gears and cone rollers acting in parallel. The rollers serve a dual function: they remove backlash from the system, and they transmit torque when the gears are not fully engaged.

  5. Roller/Gear Drives For Robotic Manipulators

    Science.gov (United States)

    Anderson, William J.; Shipitalo, William

    1995-01-01

    Pitch/yaw roller/gear drive and wrist-roll roller/gear drive designed to incorporate several features desirable in robotic-joint actuators. Includes zero backlash, high efficiency, smooth motion (little ripple in torque and in speed ratio), and high degree of back-drivability. Pitch/yaw drive is novel two-axis drive containing combination of gears, rollers, and springs acting together eliminating backlash and cogging. Wrist-roll drive more-conventional single-axis drive offering advantages like those of pitch/yaw drive.

  6. Two-axis joint assembly and method

    Science.gov (United States)

    Le, Thang D. (Inventor); Lewis, James L. (Inventor); Carroll, Monty B. (Inventor)

    2010-01-01

    In an embodiment, a two-axis joint that utilizes planar reactions to handle moments applied to the side of the joint thereby allowing the device to remain low profile and compact with minimal intrusion to the mounting surface of the two-axis joint. To handle larger moments, the diameter of the planar member can be increased without increasing the overall height of the joint assembly thereby retaining the low profile thereof. Upper and lower antifriction bearings may be positioned within a housing engage the planar member to reduce rotational friction. The upper and lower bearings and a hub which supports the planar member transfer forces produced by moments applied to the side of the joint so as to spread the forces over the area of the housing.

  7. Rocking rollers

    NARCIS (Netherlands)

    Van Kasteren, J.

    2003-01-01

    The weight of people and luggage makes the conveyor belts at Schiphol Airport sag a little, causing extra wear to both the plastic guide rollers and the rubber conveyor belt itself. Together with Karel Drenth, Gabriel Lodewijks, Professor of Transport Engineering & Logistics at Delft University of

  8. 基于SolidWorks的过山车轨道三维建模仿真%Solid Works-based 3D modeling and simulation of roller coaster track

    Institute of Scientific and Technical Information of China (English)

    银明; 杨瑞刚; 杨明亮

    2012-01-01

    This paper describes the method of 3S modeling parametric design of roller coaster by SolidWorks. With the method, 3D space model of the roller coaster track can be established and the dynamics simulation can be performed to effectively improve the design and thus to improve safety performance of the roller coaster.%阐述了应用SolidWorks对过山车进行三维参数化设计的方法,通过该方法可以建立出过山车轨道的三维空间模型,并通过该轨道模型对过山车进行动态仿真,有效改进过山车的设计,提高过山车的安全性能.

  9. Design and Dynamic Study of Friction-test Instrument of Roller Coaster Wheel-Track%过山车轮轨摩擦实验台设计及动态性能研究

    Institute of Scientific and Technical Information of China (English)

    宋海洋; 屈福政

    2013-01-01

    The friction coefficient of roller coaster wheel-track system is very important to the design of roller coaster .The paper presented the design of friction coefficient test instrument , and then did research on the dynamic a-nalysis of test instrument by using the ADAMS dynamics simulation software and ANSYS finite element analysis soft -ware.By testing out five groups of friction coefficient under different pressure through the simulation , the friction coeffi-cient about normal pressure and velocity function relation by using MATLAB software is achieved .Finally, the feasibili-ty of the test instrument is verified .%过山车轮轨系统的摩擦系数对过山车设计至关重要。首先介绍了摩擦系数测试实验台设计,然后利用ADAMS动力学仿真软件和ANSYS有限元分析软件,对实验台动态性能进行了研究。通过仿真测试出五组不同作用力下的摩擦系数,利用MATLAB软件进行数据处理,得到摩擦系数与作用力和速度的函数关系,验证了实验台的可行性。

  10. Design and Fabrication of a Two Axis Parabolic Solar Dish Collector

    Directory of Open Access Journals (Sweden)

    Prof. Sonal C Yogi

    2014-11-01

    Full Text Available The work consists of the design of the chain drive system and the fabrication of the two axis parabolic solar dish. It is a model study of the two axis parabolic dish which worked by the automatic circuit that was developed. Ready made parabolic solar dish is taken and fabricated. The circular iron ring provides the two axis motion of the dish. A compound chain drive system was developed for the smooth movement of the dish. An electromechanical system which tracks the sun on both axes and which is controlled via a programmable logic control (PLC was designed and implemented. In this a theoretical study was done. A C program was made which gave the required result for the graphical representation of the recorded radiation. Programmable Logic Controls (PLC was used instead of photo sensors, which are widely used for tracking the sun. The azimuthal angle of the sun from sunrise to sunset times was calculated for each day of the year at 23.59 Lat & 72.38Longitude in the Northern hemisphere, the location of the city Mehsana. According to this azimuth angle, the required analog signal was taken from the PLC analog module and sent to the power window motor, which controlled the position of the panel to ensure that the rays fall vertically on the panel. After the mechanical control of the system was started, the performance measurements of the solar panel were carried out. The values obtained from the measurements were compared and the necessary evaluations were conducted.

  11. The Power and Joy of Derby: Women’s Participation, Empowerment, and Transformation in a Flat-Track Roller Derby Team

    Directory of Open Access Journals (Sweden)

    John Paul

    2015-11-01

    Full Text Available In what ways do sports make a difference in the lives of the people who play them? In this paper, we employ a sporting feminist perspective to answer this question and detail how women benefit from the sport of roller derby. Our analyses are structured around the themes of the body (exploring examples of bodily empowerment and reconceptualization; the team (highlighting feminist themes of loyalty and team as family; and the crowd (identifying the ways in which derby is “sold” to the crowd, as well as the ways in which athletes use derby to challenge conceptions of beauty, desirability, and femininity. In the end, this work comments on the multiple examples of feminist expression and positive sporting participation found in derby, including the use of sport to reject notions of weakness and fragility, and a greater willingness to critically assess gender inequities beyond the world of sport.

  12. An Interval Type-2 Fuzzy Neural Network Control on Two-Axis Motion System

    Directory of Open Access Journals (Sweden)

    Ye Xiaoting

    2013-11-01

    Full Text Available In this paper, an interval type-2 fuzzy neural network (IT2FNN control system is proposed to control a two-axis motion system, which is composed of two permanent magnet linear synchronous motors. The IT2FNN control system, which combines the merits of an interval type-2 fuzzy logic system and a neural network, is developed to approximate an unknown dynamic function. Moreover, adaptive learning algorithms that can train the parameters of the IT2FNN online are derived using the Lyapunov stability theorem. Furthermore, a robust compensator is proposed to confront the uncertainties. To relax the requirement for the value of the lumped uncertainty in the robust controller, an adaptive lumped uncertainty estimation law is also investigated. The proposed control algorithms are implemented. From the simulated and experimental results, the contour tracking performance of the two-axis motion control system is significantly improved and the robustness can be obtained as well using the proposed IT2FNN control system.    

  13. Angle hybrid control for a two-axis piezo-positioning system and its application

    Science.gov (United States)

    Zhu, Wei; Zhou, Qinbo; Rui, Xiaoting

    2016-09-01

    The hysteresis characteristics of piezoelectric actuators and the residual vibration in the rapid positioning process will greatly affect the positioning accuracy and speed of a piezo-driven positioning system (PPS). In order to improve the positioning accuracy and to restrain the residual vibration of a two-axis PPS, a hybrid controller is proposed and explored based on a comprehensive model by combining the proposed feedforward linearization, the zero vibration and derivative shaping, and the linear-quadratic Gaussian feedback control for the PPS. The experimental results show that the proposed hybrid control significantly improves the positioning accuracy and suppresses the residual vibration of the PPS. Its application shows that the PPS proposed herein can effectively enhance the astronomical telescope’s star tracking and pointing performance.

  14. A broadband two axis flux-gate magnetometer

    Directory of Open Access Journals (Sweden)

    P. Palangio

    1998-06-01

    Full Text Available A broadband two axis flux-gate magnetometer was developed to obtain high sensitivity in magnetotelluric measurements. In magnetotelluric sounding, natural low frequency electromagnetic fields are used to estimate the conductivity of the Earth's interior. Because variations in the natural magnetic field have small amplitude(10-100 pT in the frequency range 1 Hz to 100 Hz, highly sensitive magnetic sensors are required. In magnetotelluric measurements two long and heavy solenoids, which must be installed, in the field station, perpendicular to each other (north-south and east-west and levelled in the horizontal plane are used. The coil is a critical component in magnetotelluric measurements because very slight motions create noise voltages, particularly troublesome in wooded areas; generally the installation takes place in a shallow trench. Moreover the coil records the derivative of the variations rather than the magnetic field variations, consequently the transfer function (amplitude and phase of this sensor is not constant throughout the frequency range 0.001-100 Hz. The instrument, developed at L'Aquila Geomagnetic Observatory, has a flat response in both amplitude and phase in the frequency band DC-100 Hz, in addition it has low weight, low power, small volume and it is easier to install in the field than induction magnetometers. The sensivity of this magnetometer is 10 pT rms.

  15. Propagation of angular errors in two-axis rotation systems

    Science.gov (United States)

    Torrington, Geoffrey K.

    2003-10-01

    Two-Axis Rotation Systems, or "goniometers," are used in diverse applications including telescope pointing, automotive headlamp testing, and display testing. There are three basic configurations in which a goniometer can be built depending on the orientation and order of the stages. Each configuration has a governing set of equations which convert motion between the system "native" coordinates to other base systems, such as direction cosines, optical field angles, or spherical-polar coordinates. In their simplest form, these equations neglect errors present in real systems. In this paper, a statistical treatment of error source propagation is developed which uses only tolerance data, such as can be obtained from the system mechanical drawings prior to fabrication. It is shown that certain error sources are fully correctable, partially correctable, or uncorrectable, depending upon the goniometer configuration and zeroing technique. The system error budget can be described by a root-sum-of-squares technique with weighting factors describing the sensitivity of each error source. This paper tabulates weighting factors at 67% (k=1) and 95% (k=2) confidence for various levels of maximum travel for each goniometer configuration. As a practical example, this paper works through an error budget used for the procurement of a system at Sandia National Laboratories.

  16. Movement decoupling control for two-axis fast steering mirror

    Science.gov (United States)

    Wang, Rui; Qiao, Yongming; Lv, Tao

    2017-02-01

    Based on flexure hinge and piezoelectric actuator of two-axis fast steering mirror is a complex system with time varying, uncertain and strong coupling. It is extremely difficult to achieve high precision decoupling control with the traditional PID control method. The feedback error learning method was established an inverse hysteresis model which was based inner product dynamic neural network nonlinear and no-smooth for piezo-ceramic. In order to improve the actuator high precision, a method was proposed, which was based piezo-ceramic inverse model of two dynamic neural network adaptive control. The experiment result indicated that, compared with two neural network adaptive movement decoupling control algorithm, static relative error is reduced from 4.44% to 0.30% and coupling degree is reduced from 12.71% to 0.60%, while dynamic relative error is reduced from 13.92% to 2.85% and coupling degree is reduced from 2.63% to 1.17%.

  17. Two Axis Pointing System (TAPS) attitude acquisition, determination, and control

    Science.gov (United States)

    Azzolini, John D.; McGlew, David E.

    1990-12-01

    The Two Axis Pointing System (TAPS) is a 2 axis gimbal system designed to provide fine pointing of Space Transportation System (STS) borne instruments. It features center-of-mass instrument mounting and will accommodate instruments of up to 1134 kg (2500 pounds) which fit within a 1.0 by 1.0 by 4.2 meter (40 by 40 by 166 inch) envelope. The TAPS system is controlled by a microcomputer based Control Electronics Assembly (CEA), a Power Distribution Unit (PDU), and a Servo Control Unit (SCU). A DRIRU-II inertial reference unit is used to provide incremental angles for attitude propagation. A Ball Brothers STRAP star tracker is used for attitude acquisition and update. The theory of the TAPS attitude determination and error computation for the Broad Band X-ray Telescope (BBXRT) are described. The attitude acquisition is based upon a 2 star geometric solution. The acquisition theory and quaternion algebra are presented. The attitude control combines classical position, integral and derivative (PID) control with techniques to compensate for coulomb friction (bias torque) and the cable harness crossing the gimbals (spring torque). Also presented is a technique for an adaptive bias torque compensation which adjusts to an ever changing frictional torque environment. The control stability margins are detailed, with the predicted pointing performance, based upon simulation studies. The TAPS user interface, which provides high level operations commands to facilitate science observations, is outlined.

  18. The World's Best Roller Coasters.

    Science.gov (United States)

    Jones, T. Griffith; Jones, Linda Cronin

    1995-01-01

    Constructing model roller coasters is a great way for students to explore concepts related to energy and motion. Describes making a model roller coaster with 4th grade students. Students learn about different forms of energy and answer their own questions about roller coasters. (NB)

  19. The World's Best Roller Coasters.

    Science.gov (United States)

    Jones, T. Griffith; Jones, Linda Cronin

    1995-01-01

    Constructing model roller coasters is a great way for students to explore concepts related to energy and motion. Describes making a model roller coaster with 4th grade students. Students learn about different forms of energy and answer their own questions about roller coasters. (NB)

  20. Roller coaster headaches revisited.

    Science.gov (United States)

    Huang, Paul P

    2003-11-01

    Roller coasters are probably one of the more popular rides at amusement parks around the world. Despite their relative safety, nontraumatic intracranial injuries have been reported following roller coaster rides. The presence of an intracranial arachnoid cyst may increase the risk of nontraumatic injury in this setting. We describe a 33-year-old female with a left middle fossa arachnoid cyst who presented with increasing headaches from bilateral subdural hygromas after a roller coaster ride. The patient underwent bilateral burr hole drainage of her subdural hygromas with resolution of her symptoms. This case demonstrates the potential risks of intracranial injury in patients with an underlying arachnoid cyst who engage in certain types of recreational activity.

  1. Rock 'n Roller Coaster

    DEFF Research Database (Denmark)

    Timmermans, Bram; Bekkers, Rudi; Bordoli, Luca

    of firms in the industry increases; (ii) the period of shakeout where the number of firms decreases; and finally, (iii) the stage of stability or maturity, during which the number of firms does not change substantially. Be that as it may, this model has several strong assumptions and, consequently...... on all the firms that are, or have been, active in the roller coaster industry. To identify background information on these firms and its founders, we use various sources of online and offline media, e.g. books, roller coaster magazines, information on trade fairs, websites of roller coaster interest......-entry experience in the same market and pre-entry experience in technological related fields. We find that these two categories of firms produce rather distinct type of products. This is also reflected by differences in patent behavior of the type of entrants. The technological related diversifiers produce...

  2. Rates of solar angles for two-axis concentrators

    Science.gov (United States)

    Yung, C. S.; Lansing, F. L.

    1982-01-01

    The Sun's position by the azimuth and elevation angles and its rate of change at any time of day are determined to design 2 axis tracking mechanisms of solar concentrators. The Sun's angles and their rates for selected months of the year (March, June, September and December) and for seven selected atitudes (0, + or - 30, + or - 60, + or - 90) covering both the northern and southern hemispheres were studied. The development of the angle and angle rate analytical expressions for any month, hour of day, and latitude provides the solar concentrator designer with a quantitative determination of the limiting Sun's position and angle rates for an accurate automatic tracking mechanism.

  3. Roller Coaster Science.

    Science.gov (United States)

    Sumners, Carolyn; Jones, Howard L.

    1983-01-01

    Discusses the science of roller coasters, relating gravity, potential/kinetic energy, inertia, and centripetal force to the various parts of the ride, providing tips on linking classroom discussions to field trips. Includes sample student activity sheet and source for additional units using amusement park rides/playground activities to teach…

  4. Roller Toaster Food Truck

    OpenAIRE

    López Tarache, Óscar Mauricio; Guerrero Prieto, Juan Sebastián

    2015-01-01

    Creación y desarrollo de un restaurante móvil "Food Truck Roller Toaster" el cual produce y comercializa Sándwiches y Ensaladas Gourmet bajo el concepto de lo Tostado. Durante la Tesis se tratan temas de desarrollo de marca, diseño de producto, estudios de mercado, entre otros.

  5. Roller Coaster Science.

    Science.gov (United States)

    Sumners, Carolyn; Jones, Howard L.

    1983-01-01

    Discusses the science of roller coasters, relating gravity, potential/kinetic energy, inertia, and centripetal force to the various parts of the ride, providing tips on linking classroom discussions to field trips. Includes sample student activity sheet and source for additional units using amusement park rides/playground activities to teach…

  6. Dropping a particle out of a roller coaster

    Science.gov (United States)

    Mungan, Carl E.; Lipscombe, Trevor C.

    2014-07-01

    A rider in a roller coaster lets go of a particle such as a small marble. How far does the marble travel horizontally from the point of release before hitting the ground, assuming the speed of the roller coaster is determined by conservation of mechanical energy starting from the highest hill up which it was pulled? Where should the marble be released along the track if one wishes to maximize the range of the marble? These questions constitute interesting variations on conventional problems in two-dimensional kinematics, appropriate for an undergraduate course in classical mechanics. Exploration of various shapes of tracks could form interesting student projects for numerical or experimental investigation.

  7. Roller Cam Positioners

    Energy Technology Data Exchange (ETDEWEB)

    Bowden, Gordon B.

    2010-12-07

    Roller Cam Positioners could support the LCLS undulator sections allowing micron sized alignment adjustment of each undulator in 5 degrees of freedom. The supports are kinematic with the number of degrees of freedom matched to the number of constraints. Ton loads are supported on simple ball bearings. Motion is intrinsically bounded. Positioning mechanisms are based on pure rolling motion with sub-micron hysteresis and micron resolution. This note describes a general purpose positioning mechanism suitable for undulator support.

  8. The roller coaster flight strategy of bar-headed geese conserves energy during Himalayan migrations

    National Research Council Canada - National Science Library

    Bishop, C M; Spivey, R J; Hawkes, L A; Batbayar, N; Chua, B; Frappell, P B; Milsom, W K; Natsagdorj, T; Newman, S H; Scott, G R; Takekawa, J Y; Wikelski, M; Butler, P J

    2015-01-01

    .... Instead, a "roller coaster" strategy, of tracking the underlying terrain and discarding large altitude gains only to recoup them later in the flight with occasional benefits from orographic lift...

  9. Statistical analysis of the performance and simulation of a two-axis tracking PV system

    Energy Technology Data Exchange (ETDEWEB)

    Perpinan, O. [Grupo de Sistemas Fotovoltaicos, IES-UPM, UPM, Ciudad Universitaria s/n, 28040 Madrid (Spain)

    2009-11-15

    The energy produced by a photovoltaic system over a given period can be estimated from the incident radiation at the site where the Grid Connected PV System (GCPVS) is located, assuming knowledge of certain basic features of the system under study. Due to the inherently stochastic nature of solar radiation, the question ''How much energy will a GCPVS produce at this location over the next few years?'' involves an exercise of prediction inevitably subjected to a degree of uncertainty. Moreover, during the life cycle of the GCPVS, another question arises: ''Is the system working correctly?''. This paper proposes and examines several methods to cope with these questions. The daily performance of a PV system is simulated. This simulation and the interannual variability of both radiation and productivity are statistically analyzed. From the results several regression adjustments are obtained. This analysis is shown to be useful both for productivity prediction and performance checking exercises. Finally, a statistical analysis of the performance of a GCPVS is carried out as a detection method of malfunctioning parts of the system. (author)

  10. Net efficiency of roller skiing with a diagonal stride.

    Science.gov (United States)

    Nakai, Akira; Ito, Akira

    2011-02-01

    The aims of this study were: (a) to determine net efficiency during roller skiing with a diagonal stride at various speeds; (b) to assess the development of net efficiency across speeds; and (c) to examine the characteristics of efficiency in diagonal roller skiing. Two-dimensional kinematics and oxygen uptake were determined in eight male collegiate cross-country ski athletes who roller skied with the diagonal stride at various speeds on a level track. Net efficiency was calculated from rates of internal and external work and net energy expenditure. Individual net efficiency ranged from 17.7% to 52.1%. Net efficiency in the entire group of athletes increased with increasing speed, reached a maximum value of 37.3% at 3.68 m · s(-1), before slowly decreasing. These findings indicate that roller skiing with the diagonal stride at high speed is a highly efficient movement and that an optimal speed exists at which net efficiency can be maximally enhanced in diagonal roller skiing.

  11. Roller Coasters Need Calculus Too!

    Directory of Open Access Journals (Sweden)

    Christina Marshall

    2011-01-01

    Full Text Available Using the specifications of the given launch roller coaster, we were able to determine the position vector of the roller coaster as a function of time. After determining the position function, we took the derivative of this function to calculate the velocity of the coaster as a function of time. From this calculated velocity vector, we were able to determine the time required for the coaster to reach its maximum height. We substitute this time value back into the position function to determine the maximum height the launch roller coaster can obtain.

  12. Roller coaster-induced barotrauma.

    Science.gov (United States)

    Al-Khudari, Samer; Loochtan, Michael; Yaremchuk, Kathleen

    2011-03-01

    We present the case of a 24-year-old male who presented to the otolaryngology clinic for otalgia and aural fullness after riding a roller coaster. We present his clinical course and outcome and briefly discuss the mechanism of injury and otologic barotrauma. Roller coasters have been reported as the cause of many different types of injuries, but this is the first reported case of otologic barotrauma. As the engineering for roller coasters continues to advance in terms of increasing speed, otolaryngologists need to be aware of a new etiology of otologic barotrauma. Copyright © 2010 The American Laryngological, Rhinological, and Otological Society, Inc.

  13. Tolerance Design of Logarithmic Roller Profiles in Cylindrical Roller Bearings

    Science.gov (United States)

    Fujiwara, Hiroki; Yamauchi, Kazuto

    A logarithmic profile is essentially optimal crowning geometry for rolling machine elements such as bearing rollers and raceways. Although some design methods of the profile have been proposed, they do not refer to the tolerance of the geometry required in engineering applications and in production. This paper shows how to define the tolerance range associated with the optimum roller profile, previously suggested by one of the authors. The overall tolerance is reasonably defined by giving the reduced amount of roller radius at three points so that the von Mises equivalent stress will not exceed a specified limit, where the point locations are not measured from the roller end but from the intersection of the crowning and the chamfer. For the purpose of design usefulness, the tolerance expression is offered in dimensionless form.

  14. Two-axis gimbal for air-to-air and air-to-ground laser communications

    Science.gov (United States)

    Talmor, Amnon G.; Harding, Harvard; Chen, Chien-Chung

    2016-03-01

    For bi-directional links between high-altitude-platforms (HAPs) and ground, and air-to-air communication between such platforms, a hemispherical +30°C field-of-regard and low-drag low-mass two-axis gimbal was designed and prototyped. The gimbal comprises two servo controlled non-orthogonal elevation over azimuth axis, and inner fast steering mirrors for fine field-of-regard adjustment. The design encompasses a 7.5cm diameter aperture refractive telescope in its elevation stage, folded between two flat mirrors with an exit lens leading to a two mirrors miniature Coude-path fixed to the azimuth stage. Multiple gimbal configurations were traded prior to finalizing a selection that met the requirements. The selected design was manifested onboard a carbon fiber and magnesium composite structure, motorized by custom-built servo motors, and commutated by optical encoders. The azimuth stage is electrically connected to the stationary base via slip ring while the elevation stage made of passive optics. Both axes are aligned by custom-built ceramic-on-steel angular contact duplex bearings, and controlled by embedded electronics featuring a rigid-flex PCB architecture. FEA analysis showed that the design is mechanically robust over a temperature range of +60°C to -80°C, and with first mode of natural frequencies above 400Hz. The total mass of the prototyped gimbal is 3.5kg, including the inner optical bench, which contains fast steering mirrors (FSMs) and tracking sensors. Future version of this gimbal, in prototyping stage, shall weigh less than 3.0kg.

  15. Roller Coasters Need Calculus Too!

    OpenAIRE

    Christina Marshall

    2011-01-01

    Using the specifications of the given launch roller coaster, we were able to determine the position vector of the roller coaster as a function of time. After determining the position function, we took the derivative of this function to calculate the velocity of the coaster as a function of time. From this calculated velocity vector, we were able to determine the time required for the coaster to reach its maximum height. We substitute this time value back into the position function to determin...

  16. Roller Coasters Need Calculus Too!

    OpenAIRE

    Christina Marshall

    2011-01-01

    Using the specifications of the given launch roller coaster, we were able to determine the position vector of the roller coaster as a function of time. After determining the position function, we took the derivative of this function to calculate the velocity of the coaster as a function of time. From this calculated velocity vector, we were able to determine the time required for the coaster to reach its maximum height. We substitute this time value back into the position function to determin...

  17. Principle of reflecting measurement system for roller wear and software simulation

    Science.gov (United States)

    Zheng, Longjiang; Wang, Kai; Guo, Yuan; Wang, Yutian

    2006-11-01

    Roller plays an important role in rolling mill. However, the effective surface of roller is limited. After long time working, the surface of roller will wear. The roller wear will result in difficult controlling of shape and thickness of steel board. Further more, it can lead to the decline of product quality. So the measurement of roller wear is very urgent for rolling mill to ensure their product quality. In this paper, a measurement method for roller wear is introduced in detail. This method offers advantages of sensitivity, immediate response, electromagnetic interference, simplicity and non-contact. It can detect in the atrocious condition on-line and examine roller wear precisely and real time. It is an effective method at low cost instance. The basic principle of this system is optical reflection principle. In the paper, after explaining the principle of this measurement system, an error compensation algorithm is exactly calculated to improve accuracy of this measurement system. This algorithm is brought out to offset the shift of measurement track. And a simulation-software program is compiled with Microsoft Visual Basic 6.0 based on this principle. By using this simulation-software, the date of I/O signal for this system is gained. And the signal verse is automatically drawn in this software.

  18. Improvement of the stone elimination roller mill

    Institute of Scientific and Technical Information of China (English)

    SunGuofeng

    2005-01-01

    Elimination roller mill as raw materials preparing equipments is universally used in brick making industry. Stone Elimination Roller Mill should have following characteristics: high machine strength and good wearresistant of roller shell, safety reliability, high machinery intensity (impact strength) and rigidity, reliable hermetically sealed construction.

  19. High-performance two-axis gimbal system for free space laser communications onboard unmanned aircraft systems

    Science.gov (United States)

    Locke, Michael; Czarnomski, Mariusz; Qadir, Ashraf; Setness, Brock; Baer, Nicolai; Meyer, Jennifer; Semke, William H.

    2011-03-01

    A custom designed and manufactured gimbal with a wide field-of-view and fast response time is developed. This enhanced custom design is a 24 volt system with integrated motor controllers and drivers which offers a full 180o fieldof- view in both azimuth and elevation; this provides a more continuous tracking capability as well as increased velocities of up to 479° per second. The addition of active high-frequency vibration control, to complement the passive vibration isolation system, is also in development. The ultimate goal of this research is to achieve affordable, reliable, and secure air-to-air laser communications between two separate remotely piloted aircraft. As a proof-of-concept, the practical implementation of an air-to-ground laserbased video communications payload system flown by a small Unmanned Aerial Vehicle (UAV) will be demonstrated. A numerical tracking algorithm has been written, tested, and used to aim the airborne laser transmitter at a stationary ground-based receiver with known GPS coordinates; however, further refinement of the tracking capabilities is dependent on an improved gimbal design for precision pointing of the airborne laser transmitter. The current gimbal pointing system is a two-axis, commercial-off-the-shelf component, which is limited in both range and velocity. The current design is capable of 360o of pan and 78o of tilt at a velocity of 60o per second. The control algorithm used for aiming the gimbal is executed on a PC-104 format embedded computer onboard the payload to accurately track a stationary ground-based receiver. This algorithm autonomously calculates a line-of-sight vector in real-time by using the UAV autopilot's Differential Global Positioning System (DGPS) which provides latitude, longitude, and altitude and Inertial Measurement Unit (IMU) which provides the roll, pitch, and yaw data, along with the known Global Positioning System (GPS) location of the ground-based photodiode array receiver.

  20. Stopping a Roller Coaster Train

    Science.gov (United States)

    Pendrill, Ann-Marie; Karlsteen, Magnus; Rodjegard, Henrik

    2012-01-01

    A roller coaster ride comes to an end. Magnets on the train induce eddy currents in the braking fins, giving a smooth rise in braking force as the remaining kinetic energy is absorbed by the brakes and converted to thermal energy. In this paper an IR camera was used to monitor the temperature of the first braking fin, before, during and after the…

  1. Stopping a Roller Coaster Train

    Science.gov (United States)

    Pendrill, Ann-Marie; Karlsteen, Magnus; Rodjegard, Henrik

    2012-01-01

    A roller coaster ride comes to an end. Magnets on the train induce eddy currents in the braking fins, giving a smooth rise in braking force as the remaining kinetic energy is absorbed by the brakes and converted to thermal energy. In this paper an IR camera was used to monitor the temperature of the first braking fin, before, during and after the…

  2. 3D Design and Analysis of Crushing Roller of High-pressure Grinding Roller

    Institute of Scientific and Technical Information of China (English)

    2002-01-01

    Crushing roller is one of the main parts of High-p re ssure Grinding Roller, which is a kind of high efficient ore crushing equipment. A kind of assembled roller, which is more convenient to renovate worn surface b y simply replacing segmented surface of the roller, was developed. The structura l models of assembled roller's components were designed with SolidWorks softwar e based on feature modeling, these solid models of the roller were virtually ass embled. Through this work, not only was the assemble i...

  3. Direct calculation of acceleration field through homogeneous transformation for two-axis centrifuge

    Institute of Scientific and Technical Information of China (English)

    吴广玉; 任顺清; 陈希军

    2003-01-01

    A precision centrifuge is an inertial navigation test equipment used for calibrating the characteristicsof accelerometers with high overloading, and a two-axis centrifuge can be used to generate either constant accel-eration or harmonic acceleration. The moving trajectory equation about the origin of the accelerometer coordinatesystem in a two-axis centrifuge was directly deduced through homogeneous transformation. The acceleration vec-tor of the origin in accelerometer coordinate system was achieved by making the second derivative of this trajec-tory equation. The acceleration components were acquired by decomposing this acceleration vector along thethree axes of the accelerometer coordinate system. The correctness of the homogeneous transformation was veri-fied through vector analysis.

  4. Use of two-axis joystick for control of externally powered shoulder disarticulation prostheses

    Directory of Open Access Journals (Sweden)

    Robert D. Lipschutz, BSME, CP

    2011-07-01

    Full Text Available We explored a new method for simple and accurate control of shoulder movement for externally powered shoulder disarticulation prostheses with a two-axis joystick. We tested 10 subjects with intact shoulders and arms to determine the average amount of shoulder motion and force available to control an electronic input device. We then applied this information to two different input strategies to examine their effectiveness: (1 a traditional rocker potentiometer and a pair of force-sensing resistors and (2 a two-axis joystick. Three nondisabled subjects and two subjects with shoulder disarticulation amputations attempted to control an experimental externally powered shoulder using both control strategies. Two powered arms were tested, one with powered flexion/extension and humeral rotation and one with powered flexion/extension and adduction/abduction. Overwhelmingly, the subjects preferred the joystick control, because it was more intuitively linked with their shoulder movement. Additionally, two motions (one in each axis could be controlled simultaneously. This pilot study provides valuable insight into an effective means of controlling high-level, externally powered prostheses with a two-axis joystick.

  5. Use of a Two-Axis Joystick for Control of Externally Powered, Shoulder Disarticulation Prostheses

    Science.gov (United States)

    Lipschutz, Robert D.; Lock, Blair; Sensinger, Jonathon; Schultz, Aimee E.; Kuiken, Todd A.

    2015-01-01

    We explored a new method for simple and accurate control of shoulder movement for externally powered shoulder disarticulation prostheses using a two-axis joystick. Ten subjects with intact shoulders and arms were tested to determine the average amount of shoulder motion and force available for control of an electronic input device. This information was then applied to two different input strategies in order to examine their effectiveness: (1) a traditional strategy implemented with a rocker potentiometer and a pair of force-sensing resistors (FSRs), and (2) a strategy implemented with a two-axis joystick. Three able-bodied subjects and two subjects with shoulder disarticulation amputations attempted to control an experimental powered shoulder using both control strategies. Two powered arms were tested, one with powered flexion/extension and humeral rotation, and one with powered flexion/extension and adduction/abduction. Overwhelmingly, the subjects preferred the joystick control, as it was more intuitively linked with their shoulder movement. Additionally, two motions (one in each axis) could be controlled simultaneously. This pilot study provides valuable insight into an effective means of controlling high-level, externally powered prostheses via a two-axis joystick. PMID:21938653

  6. Use of two-axis joystick for control of externally powered shoulder disarticulation prostheses.

    Science.gov (United States)

    Lipschutz, Robert D; Lock, Blair; Sensinger, Jonathon; Schultz, Aimee E; Kuiken, Todd A

    2011-01-01

    We explored a new method for simple and accurate control of shoulder movement for externally powered shoulder disarticulation prostheses with a two-axis joystick. We tested 10 subjects with intact shoulders and arms to determine the average amount of shoulder motion and force available to control an electronic input device. We then applied this information to two different input strategies to examine their effectiveness: (1) a traditional rocker potentiometer and a pair of force-sensing resistors and (2) a two-axis joystick. Three nondisabled subjects and two subjects with shoulder disarticulation amputations attempted to control an experimental externally powered shoulder using both control strategies. Two powered arms were tested, one with powered flexion/extension and humeral rotation and one with powered flexion/extension and adduction/abduction. Overwhelmingly, the subjects preferred the joystick control, because it was more intuitively linked with their shoulder movement. Additionally, two motions (one in each axis) could be controlled simultaneously. This pilot study provides valuable insight into an effective means of controlling high-level, externally powered prostheses with a two-axis joystick.

  7. Effect of Roller Geometry on Roller Bearing Load-Life Relation

    Science.gov (United States)

    Oswald, Fred B.; Zaretsky, Erwin V.; Poplawski, Joseph V.

    2015-01-01

    Cylindrical roller bearings typically employ roller profile modification to equalize load distribution, minimize stress concentration at roller ends and allow for a small amount of misalignment. The 1947 Lundberg-Palmgren analysis reported an inverse fourth power relation between load and life for roller bearings with line contact. In 1952, Lundberg and Palmgren changed their load-life exponent to 10/3 for roller bearings, assuming mixed line and point contact. The effect of roller-crown profile was reanalyzed in this paper to determine the actual load-life relation for modified roller profiles. For uncrowned rollers (line contact), the load-life exponent is p = 4, in agreement with the 1947 Lundberg-Palmgren value but crowning reduces the value of the exponent, p. The lives of modern roller bearings made from vacuum-processed steels significantly exceed those predicted by the Lundberg-Palmgren theory. The Zaretsky rolling-element bearing life model of 1996 produces a load-life exponent of p = 5 for flat rollers, which is more consistent with test data. For the Zaretsky model with fully crowned rollers p = 4.3. For an aerospace profile and chamfered rollers, p = 4.6. Using the 1952 Lundberg-Palmgren value p = 10/3, the value incorporated in ANSI/ABMA and ISO bearing standards, can create significant life calculation errors for roller bearings.

  8. Roller coasters: let the rider beware.

    Science.gov (United States)

    Holtzman, D K; Paul, R L

    1997-06-01

    To describe a pediatric patient with a severe abdominal injury following a roller coaster crash, and to review the relevant literature of lap belt injuries and roller coaster safety regulations. Case report. A seven-year-old girl sitting in the front seat of a two-person roller coaster car was injured when it crashed into the stopped car in front. The patient's injuries, including a partial hepatic amputation, were due to the combined forces of both passengers applied against her lap belt. Roller coaster restraint systems do not have the same federal or state oversights as motor vehicles and can result in life-threatening injuries.

  9. Design and performance test of a two-axis fast steering mirror driven by piezoelectric actuators

    Science.gov (United States)

    Fang, Chu; Guo, Jin; Yang, Guo-qing; Jiang, Zhen-hua; Xu, Xin-hang; Wang, Ting-feng

    2016-09-01

    A novel design of a two-axis fast steering mirror (FSM) with piezoelectric actuators is proposed for incoherent laser beam combination. The mechanical performance of the FSM is tested. The results show that the tilting range of the mirror is about 4 mrad, and the 1st-order resonance frequency is about 250 Hz. A self-designed grating encoder is taken as the sensor, which ensures the optimal precision of 10 μrad. The novel mechanical design can meet the requirement of engineering in incoherent laser beam combination.

  10. Relationship of rolling bearing stiffness with diameter of roller

    Institute of Scientific and Technical Information of China (English)

    郭茂林; 王刚; 张瑞

    2002-01-01

    The theoretical formula of roller bearing stiffness is induced and compared with its empirical formula.In the experience formula the stiffness of roller bearing has nothing to do with the roller diameter. The relation-ship of roller bearing stiffness with roller diameter was studied using Hz contacting theory. It is concluded thatconclusion in experience formula is only approximate result of data processing under special conditions, and therelation between stiffness of roller bearing and roller diameter must be taken into consideration while designingor selecting roller bearings.

  11. Development of Control System of Two - axis Solar Tracker%双轴式太阳跟踪装置控制系统的研究

    Institute of Scientific and Technical Information of China (English)

    耿其东; 李春燕

    2011-01-01

    介绍了双轴式太阳跟踪装置控制系统的原理及特点,设计了基于位置敏感探测器(PSD)的太阳跟踪器,实现对太阳的自动跟踪.控制系统同时采用太阳运动轨迹跟踪方法和传感器跟踪方法来完成1次跟踪,与以往2种模式相切换的控制系统相比,此系统的可靠性更好、跟踪精度更高、制造和运行成本低、性价比高,有广阔的应用前景.%This article describes the control theory and characteristic of two - axis solar track ing system, based on a position- sensitive detector a tracking device is designed and automatic track ing of sun. The control system use the methods of both program control and sensor track to complete a tracking mission, it has good reliability, high tracking accuracy, low manufacturing and operating cost, cost - effective and broad application prospects.

  12. Installation of TVC Actuators in a Two Axis Inertial Load Simulator Test Stand

    Science.gov (United States)

    Dziubanek, Adam

    2013-01-01

    This paper is about the installation of Space Shuttle Main Engines (SSME) actuators in the new Two Axis Inertial Load Simulator (ILS) at MSFC. The new test stand will support the core stage of the Space Launch System (SLS). Because of the unique geometry of the new test stand standard actuator installation procedures will not work. I have been asked to develop a design on how to install the actuators into the new test stand. After speaking with the engineers and technicians I have created a possible design solution. Using Pro Engineer design software and running my own stress calculations I have proven my design is feasible. I have learned how to calculate the stresses my design will see from this task. From the calculations I have learned I have over built the apparatus. I have also expanded my knowledge of Pro Engineer and was able to create a model of my idea.

  13. Endoscopic swept-source optical coherence tomography based on a two-axis microelectromechanical system mirror

    Science.gov (United States)

    Wang, Donglin; Fu, Linlai; Wang, Xin; Gong, Zhongjian; Samuelson, Sean; Duan, Can; Jia, Hongzhi; Ma, Jun Shan; Xie, Huikai

    2013-08-01

    A microelectromechanical system (MEMS) mirror based endoscopic swept-source optical coherence tomography (SS-OCT) system that can perform three-dimensional (3-D) imaging at high speed is reported. The key component enabling 3-D endoscopic imaging is a two-axis MEMS scanning mirror which has a 0.8×0.8 mm2 mirror plate and a 1.6×1.4 mm2 device footprint. The diameter of the endoscopic probe is only 3.5 mm. The imaging rate of the SS-OCT system is 50 frames/s. OCT images of both human suspicious oral leukoplakia tissue and normal buccal mucosa were taken in vivo and compared. The OCT imaging result agrees well with the histopathological analysis.

  14. Two-axis water-immersible microscanning mirror for scanning optics and acoustic microscopy

    Science.gov (United States)

    Xu, Song; Zou, Jun

    2016-10-01

    Fast multiaxis scanning is useful for not only optical but also acoustic microscopic imaging. Although they have been used for optical scanning, the application of (MEMS) scanning mirrors in acoustic microscopy is still very limited due to their small mirror plate size, and more importantly, inability to operate in liquids (as ultrasound coupling media). A microfabricated two-axis water-immersible scanning mirror for optical and acoustic microscopy is reported. It has an optical and acoustically reflective mirror plate (6 mm×4 mm) to provide numerical aperture for ultrasound beam steering. Electromagnetic and mechanical analysis and simulation were conducted to estimate the mechanical tilting angle and resonance frequency of both fast and slow axes, which matches well with the measurement results. The fast axis has a resonant frequency of 320 Hz in air and 220 Hz in water, which is more than 10 times higher than that of the slow axis (24 Hz in air and 14 Hz in water). Under a 100-mA driving current, the scanning angles of the fast axis reached ±9.5 deg in both air and water at the resonance frequency, respectively. The scanning angles of the slow axis reached ±15 deg in air and ±12.5 deg in water at resonant frequencies, respectively. Raster scanning of a collimated laser beam was achieved by driving both axes simultaneously close to their own resonance frequencies. The feasibility of using the two-axis water-immersible scanning mirror in scanning acoustic microscopy was also demonstrated.

  15. Roller coaster-associated retinal detachments.

    Science.gov (United States)

    Shaikh, Saad

    2011-01-01

    The purpose of this study was to report two cases of rhegmatogenous retinal detachment noted immediately after roller coaster riding in an at-risk population. In separate incidents, a 35-year-old woman and a 45-year-old woman, both significantly myopic, presented with visual symptoms after riding roller coasters. Both patients were found to have acute rhegmatogenous retinal detachments associated with myopic degenerative changes. The pathology supported an acute, traumatic etiology for the detachments. Roller coaster riding should be considered an adjunct risk factor for retinal detachment in predisposed patients.

  16. Chuanshi Brand Tri-cone Roller Bit

    Institute of Scientific and Technical Information of China (English)

    Chen Xilong; Shen Zhenzhong; Yuan Xiaoyi

    1997-01-01

    @@ Compared with other types of bits, the tri-cone roller bit has the advantages of excellent comprehensive performance, low price, wide usage range. It is free of formation limits. The tri-cone roller bit accounts for 90% of the total bits in use. The Chengdu Mechanical Works, as a major manufacturer of petroleum mechanical products and one of the four major tri-cone roller bit factories in China,has produced 120 types of bits in seven series and 19 sizes since 1967. The bits manufactured by the factory are not only sold to the domestic oilfields, but also exported to Japan, Thailand, Indonesia, the Philippines and the Middle East.

  17. Seguidor Solar de Dos Ejes para un Horno Solar Two-Axis Sun Tracking System for a Solar Furnace

    OpenAIRE

    Gabriel Villeda; Alejandro Castañeda; José T Vega; Jorge Pineda

    2011-01-01

    Se presenta el diseño y fabricación de un seguidor solar de dos ejes (rotación-elevación), el cual controla un helióstato de un horno solar para la cocción de tabiques de arcilla. El sistema trabaja con motores controlados desde una computadora personal. El algoritmo para el seguidor solar se desarrolló en un lenguaje de programación visual, calcula los ángulos de seguimiento primario y secundario del helióstato y los despliega en una pantalla. El microcontrolador está programado para control...

  18. Low-Friction, Low-Profile, High-Moment Two-Axis Joint

    Science.gov (United States)

    Lewis, James L.; Le, Thang; Carroll, Monty B.

    2010-01-01

    The two-axis joint is a mechanical device that provides two-degrees-of-freedom motion between connected components. A compact, moment-resistant, two-axis joint is used to connect an electromechanical actuator to its driven structural members. Due to the requirements of the overall mechanism, the joint has a low profile to fit within the allowable space, low friction, and high moment-reacting capability. The mechanical arrangement of this joint can withstand high moments when loads are applied. These features allow the joint to be used in tight spaces where a high load capability is required, as well as in applications where penetrating the mounting surface is not an option or where surface mounting is required. The joint consists of one base, one clevis, one cap, two needle bearings, and a circular shim. The base of the joint is the housing (the base and the cap together), and is connected to the grounding structure via fasteners and a bolt pattern. Captive within the housing, between the base and the cap, are the rotating clevis and the needle bearings. The clevis is attached to the mechanical system (linear actuator) via a pin. This pin, and the rotational movement of the clevis with respect to the housing, provides two rotational degrees of freedom. The larger diameter flange of the clevis is sandwiched between a pair of needle bearings, one on each side of the flange. During the assembly of the two-axis joint, the circular shims are used to adjust the amount of preload that is applied to the needle bearings. The above arrangement enables the joint to handle high moments with minimal friction. To achieve the high-moment capability within a low-profile joint, the use of depth of engagement (like that of a conventional rotating shaft) to react moment is replaced with planar engagement parallel to the mounting surface. The needle bearings with the clevis flange provide the surface area to react the clevis loads/moments into the joint housing while providing minimal

  19. Two-Axis Solar Heat Collection Tracker System for Solar Thermal Applications

    Directory of Open Access Journals (Sweden)

    Tsung-Chieh Cheng

    2013-01-01

    Full Text Available An experimental study was performed to investigate the effect of using a continuous operation two-axes tracking on the solar heat energy collected. This heat-collection sun tracking which LDR (light dependent resistor sensors installed on the Fersnel lens was used to control the tracking path of the sun with programming method of control with a closed loop system. The control hardware was connected to a computer through Zigbee wireless module and it also can monitor the whole tracking process information on a computer screen. An experimental study was performed to investigate the effect of using two-axes tracking on the solar heat energy collected. The results indicate that sun tracking systems are being increasingly employed to enhance the efficiency of heat collection by polar-axis tracking of the sun. Besides, the heating power was also measured by designed power measurement module at the different focal length of Fresnel lens, and the design of shadow mask of LDR sensors is an important factor for solar photothermal applications. Moreover, the results also indicated that the best time to obtain the largest solar irradiation power is during 11:00 –13:00  in Taiwan.

  20. Two-axis polydimethylsiloxane-based electromagnetic microelectromechanical system scanning mirror for optical coherence tomography

    Science.gov (United States)

    Kim, Sehui; Lee, Changho; Kim, Jin Young; Kim, Jeehyun; Lim, Geunbae; Kim, Chulhong

    2016-10-01

    Compact size and fast imaging abilities are key requirements for the clinical implementation of an optical coherence tomography (OCT) system. Among the various small-sized technology, a microelectromechanical system (MEMS) scanning mirror is widely used in a miniaturized OCT system. However, the complexities of conventional MEMS fabrication processes and relatively high costs have restricted fast clinical translation and commercialization of the OCT systems. To resolve these problems, we developed a two-axis polydimethylsiloxane (PDMS)-based MEMS (2A-PDMS-MEMS) scanning mirror through simple processes with low costs. It had a small size of 15×15×15 mm3, was fast, and had a wide scanning range at a low voltage. The AC/DC responses were measured to evaluate the performance of the 2A-PDMS-MEMS scanning mirror. The maximum scanning angles were measured as ±16.6 deg and ±11.6 deg along the X and Y axes, respectively, and the corresponding field of view was 29.8 mm×20.5 mm with an optical focal length of 50 mm. The resonance frequencies were 82 and 57 Hz along the X and Y axes, respectively. Finally, in vivo B-scan and volumetric OCT images of human fingertips and palms were successfully acquired using the developed SD-OCT system based on the 2A-PDMS-MEMS scanning mirror.

  1. Spontaneous transfer of chirality in an atropisomerically enriched two-axis system.

    Science.gov (United States)

    Barrett, Kimberly T; Metrano, Anthony J; Rablen, Paul R; Miller, Scott J

    2014-05-01

    One of the most well-recognized stereogenic elements in a chiral molecule is an sp(3)-hybridized carbon atom that is connected to four different substituents. Axes of chirality can also exist about bonds with hindered barriers of rotation; molecules containing such axes are known as atropisomers. Understanding the dynamics of these systems can be useful, for example, in the design of single-atropisomer drugs or molecular switches and motors. For molecules that exhibit a single axis of chirality, rotation about that axis leads to racemization as the system reaches equilibrium. Here we report a two-axis system for which an enantioselective reaction produces four stereoisomers (two enantiomeric pairs): following a catalytic asymmetric transformation, we observe a kinetically controlled product distribution that is perturbed from the system's equilibrium position. As the system undergoes isomerization, one of the diastereomeric pairs drifts spontaneously to a higher enantiomeric ratio. In a compensatory manner, the enantiomeric ratio of the other diastereomeric pair decreases. These observations are made for a class of unsymmetrical amides that exhibits two asymmetric axes--one axis is defined through a benzamide substructure, and the other axis is associated with differentially N,N-disubstituted amides. The stereodynamics of these substrates provides an opportunity to observe a curious interplay of kinetics and thermodynamics intrinsic to a system of stereoisomers that is constrained to a situation of partial equilibrium.

  2. Monolithically integrated two-axis microgripper for polarization maintaining in optical fiber assembly.

    Science.gov (United States)

    Zhang, Jianbin; Lu, Kangkang; Chen, Weihai; Jiang, Jun; Chen, Wenjie

    2015-02-01

    Polarization maintaining optical fiber (PMOF) is a kind of special optical fiber that is designed to transmit the linearly polarized light. Unlike the general optical fiber, it is critical to conduct the rotational alignment between two PMOFs to guarantee the efficiency of light transmission. Until now, this alignment task still cannot be addressed with an efficient and economical way. Hence, we propose a monolithically integrated two-axis flexure-based microgripper that has the grasping and rubbing functions. To achieve a compact structure, the microgripper is designed with an asymmetric architecture. In this paper, the pseudo-rigid body model approach and finite element analysis are conducted to provide the essential guideline to accomplish the theoretical design. The prototype is fabricated by wire electrical discharge machining, with which two experiments are conducted to validate the performance of the microgripper. The experimental results demonstrate that the proposed microgripper can firmly grasp the optical fiber with the diameter of 250 μm and meanwhile can rub it more than 90° accurately and effectively, which indicate that it can satisfy the operating requirements well in the PMOF assembly.

  3. Investigation on coaxial stability of nano-bearing under two axis-deviation perturbations

    Institute of Scientific and Technical Information of China (English)

    2010-01-01

    A spatial cylindrical model on nano-bearing constructed by double-walled carbon nano-tube (DWCNT) is established. Two motion equations are advanced to characterize the eccentric and deflective mode of the nano-bearing, respectively. On the basis of these equations, the coaxial stability of the nano-bearing under two axis-deviation perturbations is investigated. A characteristic parameter λ * governing the coaxial stability of the nano-bearing is determined. The influences of the angular velocity, interlayer spacing and axial length of the nano-bearing on the characteristic parameter λ * are analyzed and discussed in detail. It is found that when the angular velocity or interlayer spacing is smaller than a certain critical value, the parameter λ * keeps negative, and the coaxial stability of the nano-bearing is maintained. However, the axial length has very insignificant influence on λ * . In addition, for the two non-coaxial modes, the eccentric mode occurs more easily than the deflective one. The results of this paper provide a further insight into the coaxial stability of nano-bearing via the spatial model.

  4. Pulmonary hemorrhage resulting from roller coaster.

    Science.gov (United States)

    Yin, Ming; Tian, Qing; Shen, Hong

    2011-03-01

    Roller coasters are probably one of the more popular rides at amusement parks around the world, and there are few reported injuries. We report a case of symmetric diffuse upper lobe hemorrhage resulting from roller coaster in a previously healthy woman. The clinical course, management, and etiology of her case are discussed; and the literature is reviewed. To our knowledge, pulmonary hemorrhage in this setting has not yet been described.

  5. Large Area Roller Embossing of Multilayered Ceramic Green Composites

    CERN Document Server

    Shan, X; Shi, C W P; Tay, C K; Lu, C W

    2008-01-01

    In this paper, we will report our achievements in developing large area patterning of multilayered ceramic green composites using roller embossing. The aim of our research is to pattern large area ceramic green composites using a modified roller laminating apparatus, which is compatible with screen printing machines, for integration of embossing and screen printing. The instrumentation of our roller embossing apparatus, as shown in Figure1, consists of roller 1 and rollers 2. Roller 1 is heated up to the desired embossing temperature ; roller 2 is, however, kept at room temperature. The mould is a nickel template manufactured by plating nickel-based micro patterns (height : 50 $\\mu$m) on a nickel film (thickness : 70 $\\mu$m) ; the substrate for the roller embossing is a multilayered Heraeus Heralock HL 2000 ceramic green composite. Comparing with the conventional simultaneous embossing, the advantages of roller embossing include : (1) low embossing force ; (2) easiness of demoulding ; (3) localized area in co...

  6. Environmental impact studies of Chrome rollers used by cotton roller ginning industries and design and development of pollution free chromeless RCF rollers.

    Science.gov (United States)

    Singh, Gurdeep; Iyer, G Vijayan

    2004-01-01

    This study focuses on environmental chromium contamination and pollution caused by the use of Chrome Composite Leather-Clad (CCLC) rollers commonly used in cotton roller ginning industries and attempts to eliminate this problem by providing eco-friendly chrome-less rollers.

  7. Sound propagation in two-axis underwater channel based on beam-displacement ray-mode theory

    Institute of Scientific and Technical Information of China (English)

    2007-01-01

    Sound propagation in a deep ocean two-axis underwater channel is often complex and difficult to simulate between surface channel and sound fixing and ranging (SOFAR) channel. The beam-displacement ray-mode (BDRM) theory is a normal mode method for propagation modeling in horizontally stratified shallow water. An improved method for computing the upper boundary reflection coefficient in the BDRM is proposed and applied to calculate the acoustic fields of a two-axis underwater channel. Transmission losses in the two-axis underwater channel are calculated in the new BDRM. The corresponding results are in good agreement with those from the Kraken code, and furthermore the computed speed of the new BDRM excels the other methods.

  8. Characteristics of Left-Right Spiral Hollow Cylindrical Roller

    Institute of Scientific and Technical Information of China (English)

    Liming Lu; Qiping Chen; Yujiang Qin

    2015-01-01

    Based on new rolling⁃sliding compound bearings, the wear between the one⁃way spiral hollow cylindrical roller and the ribs of the inner and outer ring of rolling⁃sliding compound bearings is reduced by innovational structural design. A new left⁃right spiral hollow cylindrical roller is proposed to replace the one⁃way spiral hollow cylindrical roller. The finite element analysis models of ordinary cylindrical rollers, one⁃way spiral hollow cylindrical rollers and left⁃right spiral hollow cylindrical rollers are respectively established by ABAQUS. The axial displacement of their center mass and the stress distribution of left⁃right spiral hollow cylindrical rollers are compared and analyzed. Theoretical study results show that this new left⁃right spiral hollow cylindrical roller not only inherits the advantages of one⁃way spiral hollow cylindrical rollers, but also avoids the axial offset and the serious wear of the one⁃way spiral hollow cylindrical roller. And the theory research conclusion is verified by the experiment. The left⁃right spiral hollow cylindrical roller has the advantages to overcome boundary stress concentration like logarithmic convex roller. The rolling⁃sliding compound bearings equipped with the new rollers can be better to adapt to the impact of vibration load.

  9. Adhesive Wear of Rollers in Vacuum

    Science.gov (United States)

    Shaeef, Iqbal; Krantz, Timothy L.

    2012-01-01

    This work was done to support NASA's James Webb Space Telescope that is equipped with a Near Infrared Camera and Spectrograph and Micro Shutter Assembly (MSA). A MSA mechanism's qualification test in cryogenic vacuum at 30deg K for 96K cycles resulted in roller wear and formation of some debris. Lab tests in vacuum were conducted at NASA Glenn Research Center (GRC) to understand the wear of Ti6Al4V mated with 440F steel rollers. Misalignment angle was found to have the most significant effect on debris formation. At misalignment angle of 1.4deg, significant amount of wear debris were formed within 50,000 cycles. Very few wear particles were found for a zero misalignment angle, and the total wear was small even after 367,000 cycles. The mode of wear in all the tests was attributed to adhesion, which was clearly evident from video records as well as the plate-like amalgamated debris material from both rollers. The adhesive wear rate was found to be approximately proportional to the misalignment angle. The wear is a two-way phenomenon, and the mixing of both roller materials in wear debris was confirmed by x-ray fluorescence (XRF) and EDX spectra. While there was a net loss of mass from the steel rollers, XRF and energy dispersive x-ray (EDX) spectra showed peaks of Ti on steel rollers, and peaks of Fe on Ti rollers. These results are useful for designers in terms of maintaining appropriate tolerances to avoid misalignment of rolling elements and the resulting severe wear

  10. A FILTRATION METHOD AND APPARATUS INCLUDING A ROLLER WITH PORES

    DEFF Research Database (Denmark)

    2008-01-01

    The present invention offers a method for separating dry matter from a medium. A separation chamber is at least partly defined by a plurality of rollers (2,7) and is capable of being pressure regulated. At least one of the rollers is a pore roller (7) having a surface with pores allowing permeabi...

  11. 49 CFR 230.103 - Tender roller bearing journal boxes.

    Science.gov (United States)

    2010-10-01

    ... 49 Transportation 4 2010-10-01 2010-10-01 false Tender roller bearing journal boxes. 230.103... Locomotives and Tenders Running Gear § 230.103 Tender roller bearing journal boxes. Tender roller bearing journal boxes shall be maintained in a safe and suitable condition....

  12. Self-Mobilization Using a Foam Roller Versus a Roller Massager: Which Is More Effective for Increasing Hamstrings Flexibility?

    Science.gov (United States)

    DeBruyne, Danielle M; Dewhurst, Marina M; Fischer, Katelyn M; Wojtanowski, Michael S; Durall, Chris

    2017-01-01

    Clinical Scenario: Increasing the length of the muscle-tendon unit may prevent musculotendinous injury. Various methods have been proposed to increase muscle-tendon flexibility, including self-mobilization using foam rollers or roller massagers, although the effectiveness of these devices is uncertain. This review was conducted to determine if the use of foam rollers or roller massagers to improve hamstrings flexibility is supported by moderate- to high-quality evidence.

  13. Riding the Metalloproteinase Roller Coaster.

    Science.gov (United States)

    Murphy, Gillian

    2017-03-15

    To many of us in the field, working on Matrix Metalloproteinases (MMPs) has felt like riding a roller coaster, traveling through times of both excitement and despair. I was fortunate to join the ride when it was a mere carousel of three activities thought to target the proteins that comprise the extracellular matrix (ECM). New technologies brought the thrills of discovery, as we uncovered specific proteinase genes and defined specialised activities in different cellular processes. The MMPs and the sister families of 'A Disintegrin And Metalloproteinase' (ADAMs), ADAMs with ThromboSpondin domains (ADAM-TS) and Astacins are now recognised as key signalling 'scissors' that drive rapid changes in a plethora of cellular pathways. My many excellent colleagues and collaborators and I were enthused to contribute to the early development of the field and continue to be amazed at its growth and sophistication. In contrast, the hype and failure of early inhibitor discovery have dogged our standing with the pharmaceutical industry and grant giving bodies. However, the true believers have kept going, and knowledge of particular functions of MMPs and their contributions to disease progression has progressed. Recognition of the strategic importance of proteinase function should inspire more work harnessing new technologies such as imaging, proteomics and gene editing to generate a more precise understanding of individual situations. New approaches to inhibitor design and assessment are possible and the consequent ability to precisely abrogate specific MMP activity could contribute to the fight against a number of pathologies with unmet needs. What a ride it could be!

  14. Roller coaster migraine: an underreported injury?

    Science.gov (United States)

    McBeath, J G; Nanda, A

    2000-10-01

    A 28-year-old woman presented with severe headache, sleep problems, memory problems, and irritability 2 months after a violent roller coaster ride. She was diagnosed with posttraumatic migraine, and intravenous dihydroergotamine resolved her symptoms. Imaging studies, electroencephalogram, and visual and auditory evoked responses were normal. Imipramine, divalproex sodium, and propranolol were prescribed to prevent the headaches from recurring and dihydroergotamine nasal spray was prescribed for breakthrough headaches. We consider the many short but significant brain insults delivered during the roller coaster ride a critical factor in triggering this instance of posttraumatic migraine, which while unmanaged was a source of significant disability for the patient.

  15. Physics and roller coasters-The Blue Streak at Cedar Point

    Science.gov (United States)

    Speers, Robert R.

    1991-06-01

    The use of a roller coaster for external classroom studies of kinematics, forces, dynamics, and energy conservation is discussed. Experimental accelerometer measurements of the vertical forces acting on riders of the Blue Streak at Cedar Point in Sandusky, Ohio are presented. Theoretically, the track profile is used to calculate/predict the vertical forces acting on a rider at the hilltops, valley bottoms, and several other points of interest along the track. Finally the experimental results and theoretical predictions are compared in the context of a rider's experiences.

  16. A microneedle roller for transdermal drug delivery.

    Science.gov (United States)

    Park, Jung-Hwan; Choi, Seong-O; Seo, Soonmin; Choy, Young Bin; Prausnitz, Mark R

    2010-10-01

    Microneedle rollers have been used to treat large areas of skin for cosmetic purposes and to increase skin permeability for drug delivery. In this study, we introduce a polymer microneedle roller fabricated by inclined rotational UV lithography, replicated by micromolding hydrophobic polylactic acid and hydrophilic carboxy-methyl-cellulose. These microneedles created micron-scale holes in human and porcine cadaver skin that permitted entry of acetylsalicylic acid, Trypan blue and nanoparticles measuring 50nm and 200nm in diameter. The amount of acetylsalicylic acid delivered increased with the number of holes made in the skin and was 1-2 orders of magnitude greater than in untreated skin. Lateral diffusion in the skin between holes made by microneedles followed expected diffusional kinetics, with effective diffusivity values that were 23-160 times smaller than in water. Compared to inserting microneedles on a flat patch, the sequential insertion of microneedles row by row on a roller required less insertion force in full-thickness porcine skin. Overall, polymer microneedle rollers, prepared from replicated polymer films, offer a simple way to increase skin permeability for drug delivery.

  17. Rock ‘n Roller Coaster

    DEFF Research Database (Denmark)

    Timmermans, Bram; Bekkers, Rudi; Bordoli, Luca

    This article investigates the 50 years evolution of the European steel roller coaster industry, which can be classified as a complex products systems (CoPS) industry. This industry is characterized as a non-shake out industry where entry can be divided in three waves, i.e. early diversifiers, new...

  18. Rock ‘n Roller Coaster

    DEFF Research Database (Denmark)

    Timmermans, Bram; Bekkers, Rudi; Bordoli, Luca

    This article investigates the 50 years evolution of the European steel roller coaster industry, which can be classified as a complex products systems (CoPS) industry. This industry is characterized as a non-shake out industry where entry can be divided in three waves, i.e. early diversifiers, new...

  19. ROLLER COMPACTED CONCRETE RCC UNTUK BANGUNAN BENDUNGAN

    Directory of Open Access Journals (Sweden)

    Handoko Sugiharto

    2003-01-01

    Full Text Available The using of Roller Compacted Concrete (RCC is one of many alternatives that can be used to decrease dam construction cost. Many Roller Compacted Concrete (RCC composition has been developed to achieve maximum compressive strength. Due to the economical consideration and the possibility of the execution, drop hammer system has been used for this research. Compression test is done after the age of the sample reaches seven, 28, 60, and 90 days. The result shows that 60/40 composition of gravel/sand has higher average compressive strength on all age of sample. The highest compressive strength the achieve is 17.78 MPa for 90 days sample. Abstract in Bahasa Indonesia : Penggunaan Roller Compacted Concrete (RCC merupakan salah satu alternatif yang dapat digunakan untuk mengurangi biaya pembuatan konstruksi bendungan. Berbagai komposisi benda uji Roller Compacted Concrete (RCC dibuat untuk mengetahui kuat tekan yang paling maksimal. Ditinjau dari segi ekonomis dan kemudahan pelaksanaan, maka digunakan sistem alat pemadat drop hammer. Dilakukan tes kuat tekan setelah umur benda uji masing-masing mencapai tujuh, 28, 60, dan 90 hari. Hasil penelitian menunjukkan bahwa komposisi kerikil/pasir sebesar 60/40 selalu memiliki kuat tekan rata-rata yang lebih tinggi pada semua umur benda uji. Kuat tekan terbesar pada benda uji umur 90 hari mencapai 17.78 MPa.

  20. Pervasive liquid metal based direct writing electronics with roller-ball pen

    Energy Technology Data Exchange (ETDEWEB)

    Zheng, Yi; Zhang, Qin [Beijing Key Lab of CryoBiomedical Eng. and Key Lab of Cryogenics, Technical Institute of Physics and Chemistry, Chinese Academy of Sciences, Beijing 100190 (China); Liu, Jing, E-mail: jliu@mail.ipc.ac.cn [Beijing Key Lab of CryoBiomedical Eng. and Key Lab of Cryogenics, Technical Institute of Physics and Chemistry, Chinese Academy of Sciences, Beijing 100190 (China); Department of Biomedical Engineering, School of Medicine, Tsinghua University, Beijing 100084 (China)

    2013-11-15

    A roller-ball pen enabled direct writing electronics via room temperature liquid metal ink was proposed. With the rolling to print mechanism, the metallic inks were smoothly written on flexible polymer substrate to form conductive tracks and electronic devices. The contact angle analyzer and scanning electron microscope were implemented to disclose several unique inner properties of the obtained electronics. An ever high writing resolution with line width and thickness as 200 μm and 80 μm, respectively was realized. Further, with the administration of external writing pressure, GaIn{sub 24.5} droplets embody increasing wettability on polymer which demonstrates the pervasive adaptability of the roller-ball pen electronics.

  1. Head motions while riding roller coasters: Implications for brain injury

    OpenAIRE

    Pfister, Bryan J.; Chickola, Larry; Smith, Douglas H.

    2009-01-01

    The risk of traumatic brain injury (TBI) while riding roller coasters has received substantial attention. Case reports of TBI around the time of riding roller coasters have led many medical professionals to assert that the high gravitational forces (G-forces) induced by roller coasters pose a significant TBI risk. Head injury research, however, has shown that G-forces alone cannot predict TBI. Established head injury criterions and procedures were employed to compare the potential of TBI betw...

  2. Roller-coaster Life in China

    Institute of Scientific and Technical Information of China (English)

    Anthony; L.Iacono

    2008-01-01

    Our arrival in Changzhou in late Au- gust was the start of a roller-coaster ride.The stability and peace of a few days always gave away to the stress and frustration of the days after, only to return once again to calm in the following days.Adjusting to the local conditions is proved dif- ficult,and even now,after living in China for a year, negativity still arises in response to certain behav-

  3. An automatic registration system of multi-view 3D measurement data using two-axis turntables

    Science.gov (United States)

    He, Dong; Liu, Xiaoli; Cai, Zewei; Chen, Hailong; Peng, Xiang

    2016-09-01

    Automatic registration is a key researcher issue in 3D measurement field. In this work, we developed the automatic registration system, which is composed of a stereo system with structured light and two axis turntables. To realize the fully automatically 3D point registration, the novel method is proposed for calibration the stereo system and the two turntable direction vector simultaneously. The plane calibration rig with marked points was placed on the turntable and was captured by the left and right cameras of the stereo system with different rotation angles of the two axis turntable. By the shot images, a stereo system (intrinsically and extrinsically) was calibrated with classics camera model, and reconstruction 3D coordinates of the marked points with different angle of the two turntable. The marked point in different angle posted the specific circle, and the normal line of the circle around the turntable axis direction vector. For the each turntable, different points have different circle and normal line, and the turntable axis direction vector is calculated by averaging the different normal line. And the result show that, the proposed registration system can precisely register point cloud under the different scanning angles. In addition, there are no the ICP iterative procedures, and that make it can be used in registration of the point cloud without the obvious features like sphere, cylinder comes and the other rotator.

  4. An implantable two axis micromanipulator made with a 3D printer for recording neural activity in free-swimming fish.

    Science.gov (United States)

    Rogers, Loranzie S; Van Wert, Jacey C; Mensinger, Allen F

    2017-08-15

    Chronically implanted electrodes allow monitoring neural activity from free moving animals. While a wide variety of implanted headstages, microdrives and electrodes exist for terrestrial animals, few have been developed for use with aquatic animals. A two axis micromanipulator was fabricated with a Formlabs 3D printer for implanting electrodes into free-swimming oyster toadfish (Opsanus tau). The five piece manipulator consisted of a base, body, electrode holder, manual screw drive and locking nut. The manipulator measured approximately 25×20×30mm (l×w×h) and weighed 5.28g after hand assembly. Microwire electrodes were inserted successfully with the manipulator to record high fidelity signals from the anterior lateral line nerve of the toadfish. The micromanipulator allowed the chronically implanted electrodes to be repositioned numerous times to record from multiple sites and extended successful recording time in the toadfish by several days. Three dimensional printing allowed an inexpensive (<$US 5 material), two axis micromanipulator to be printed relatively rapidly (<2h) to successfully record from multiple sites in the anterior lateral line nerve of free-swimming toadfish. Copyright © 2017 Elsevier B.V. All rights reserved.

  5. Traction coefficient in a roller-inner ring EHD contact in a jet engine roller bearing

    Energy Technology Data Exchange (ETDEWEB)

    Sottomayor, A. [INEGI-CETRIB, Faculdade de Engenharia da Universidade do Porto (Portugal); Campos, A. [INEGI-CETRIB, Faculdade de Engenharia da Universidade do Porto (Portugal); Seabra, J. [Dept. de Engenharia Mecanica e Gestao Industrial, Faculdade de Engenharia da Universidade do Porto (Portugal)

    1997-08-01

    A simplified non-newtonian EHD model developed previously is used for the analysis of a roller-inner ring contact in a jet engine roller bearing. The lubricant behaves according to the viscoelastic rheological model, with a Ree-Eyring fluid, and the lubricant parameters are function of the pressure, temperature and rolling speed. The traction coefficient results obtained with this model are compared with previous experimental results obtained in a twin-disk machine. Finally, the influence of the operating conditions (pressure, temperature, rolling speed and slide-to-roll ratio) and of the waviness of the contacting surfaces, on the traction coefficient inside the roller-inner ring contact, is analysed. (orig.)

  6. Eco-friendly rubberized cotton fabric roller for ginning machines.

    Science.gov (United States)

    Iyer, G V

    2007-01-01

    This article discusses the pollution caused by chrome composite leather-clad (CCLC) rollers commonly used in cotton roller ginning mills and suggests an alternative roller material. CCLC rollers contain about 18,000 to 36,000 mg/kg (ppm) total chromium in trivalent and hexavalent forms, which are toxic to human health and carcinogenic. When seed-cotton is processed in double roller (DR) ginning machines, the lint is contaminated with chromium, and chromium particles are carried into the spun yarns and cotton by-products. Specifically, due to persistent rubbing of the leather-clad roller over the stationary knife during the ginning process, the lint is contaminated with about 140 to 1990 ppm of chromium, and the spun yarns and cotton by-products contain about 100 to 200 ppm, far in excess of the standard limit of 0.1 ppm. Gin and mill workers are directly exposed to this carcinogenic substance. To offset this problem, pollution-free rubberized cotton fabric (RCF) rollers have been fabricated and tested in roller gins. The RCF roller covering is made of multiple layers of fabric bonded together using a white rubber compound, which has a surface finish conducive to high ginning efficiency. This eliminates chromium contamination and pollution during the ginning process. On the basis of the design and development of various test rollers and subsequent evaluation studies, the performance of pollution-free RCF rollers has been demonstrated with reference to their commercial benefit and eco-friendliness in cotton ginning mills.

  7. Miniature endoscopic optical coherence tomography probe employing a two-axis microelectromechanical scanning mirror with through-silicon vias.

    Science.gov (United States)

    Liu, Lin; Wu, Lei; Sun, Jingjing; Lin, Elaine; Xie, Huikai

    2011-02-01

    We present the design and experimental results of a new MEMS-based endoscopic optical coherence tomography (OCT) probe. The uniqueness of this miniature OCT imaging probe is a two-axis MEMS mirror with through-silicon vias (TSVs) for interconnecting. The TSV interconnection enables ultracompact probe design, successfully reducing the probe size to only 2.6 mm in diameter. The MEMS mirror is actuated by an electrothermal actuator that is capable of scanning ± 16° at only 3.6 V DC. Two-dimensional and three-dimensional OCT images of microspheres embedded in PDMS and acute rat brain tissue have been obtained with this miniature probe in a time-domain OCT system.

  8. Two-axis MEMS scanner with transfer-printed high-reflectivity, broadband monolithic silicon photonic crystal mirrors.

    Science.gov (United States)

    Jeong, Jae-Woong; Park, Bryan; Keum, Hohyun; Kim, Seok; Rogers, John A; Solgaard, Olav

    2013-06-03

    We present a two-axis electrostatic MEMS scanner with high-reflectivity monolithic single-crystal-silicon photonic crystal (PC) mirrors suitable for applications in harsh environments. The reflective surfaces of the MEMS scanner are transfer-printed PC mirrors with low polarization dependence, low angular dependence, and reflectivity over 85% in the wavelength range of 1490nm~1505nm and above 90% over the wavelength band of 1550~1570nm. In static mode, the scanner has total scan range of 10.2° on one rotation axis and 7.8° on the other. Dynamic operation on resonance increase the scan range to 21° at 608Hz around the outer rotation axis and 9.5° at 1.73kHz about the inner rotation axis.

  9. Physical parameter identification method based on modal analysis for two-axis on-road vehicles: Theory and simulation

    Science.gov (United States)

    Zheng, Minyi; Zhang, Bangji; Zhang, Jie; Zhang, Nong

    2016-07-01

    Physical parameters are very important for vehicle dynamic modeling and analysis. However, most of physical parameter identification methods are assuming some physical parameters of vehicle are known, and the other unknown parameters can be identified. In order to identify physical parameters of vehicle in the case that all physical parameters are unknown, a methodology based on the State Variable Method(SVM) for physical parameter identification of two-axis on-road vehicle is presented. The modal parameters of the vehicle are identified by the SVM, furthermore, the physical parameters of the vehicle are estimated by least squares method. In numerical simulations, physical parameters of Ford Granada are chosen as parameters of vehicle model, and half-sine bump function is chosen to simulate tire stimulated by impulse excitation. The first numerical simulation shows that the present method can identify all of the physical parameters and the largest absolute value of percentage error of the identified physical parameter is 0.205%; and the effect of the errors of additional mass, structural parameter and measurement noise are discussed in the following simulations, the results shows that when signal contains 30 dB noise, the largest absolute value of percentage error of the identification is 3.78%. These simulations verify that the presented method is effective and accurate for physical parameter identification of two-axis on-road vehicles. The proposed methodology can identify all physical parameters of 7-DOF vehicle model by using free-decay responses of vehicle without need to assume some physical parameters are known.

  10. Roller coaster related fatalities, United States, 1994--2004.

    Science.gov (United States)

    Pelletier, A R; Gilchrist, J

    2005-10-01

    To determine the number of fatalities related to roller coasters and examine factors common to multiple incidents. A case was defined as the death of a person, which was associated with a roller coaster in the United States between 15 May 1994 and 14 May 2004. Cases were identified from four (1) Consumer Product Safety Commission, (2) Lexis-Nexis, (3) Medline, and (4) Safer parks. Forty people, ranging in age from 7 to 77 years, were killed in 39 separate incidents. Twenty nine (73%) deaths occurred among roller coaster patrons. Eleven fatalities resulted from external causes related to injuries from falls or collisions. Eighteen people died from medical conditions that might have been caused or exacerbated by riding a roller coaster; 15 were the result of intracranial hemorrhages or cardiac problems. Eleven (28%) deaths involved employees; all were caused by injuries. Approximately four deaths annually in the United States are associated with roller coasters. Prevention of roller coaster fatalities is dependent on establishing an effective surveillance system for amusement ride injuries, engineering rides to better protect both patrons and employees, improving training and supervision of employees regarding safety precautions, and posting cautionary notices near roller coasters for people with specified medical conditions. Further research is needed on roller coaster related deaths resulting from intracranial hemorrhages and cardiac problems.

  11. Roller coaster related fatalities, United States, 1994–2004

    Science.gov (United States)

    Pelletier, A; Gilchrist, J

    2005-01-01

    Objective: To determine the number of fatalities related to roller coasters and examine factors common to multiple incidents. Methods: A case was defined as the death of a person, which was associated with a roller coaster in the United States between 15 May 1994 and 14 May 2004. Cases were identified from four data sources: (1) Consumer Product Safety Commission, (2) Lexis-Nexis, (3) Medline, and (4) Saferparks. Results: Forty people, ranging in age from 7 to 77 years, were killed in 39 separate incidents. Twenty nine (73%) deaths occurred among roller coaster patrons. Eleven fatalities resulted from external causes related to injuries from falls or collisions. Eighteen people died from medical conditions that might have been caused or exacerbated by riding a roller coaster; 15 were the result of intracranial hemorrhages or cardiac problems. Eleven (28%) deaths involved employees; all were caused by injuries. Conclusions: Approximately four deaths annually in the United States are associated with roller coasters. Prevention of roller coaster fatalities is dependent on establishing an effective surveillance system for amusement ride injuries, engineering rides to better protect both patrons and employees, improving training and supervision of employees regarding safety precautions, and posting cautionary notices near roller coasters for people with specified medical conditions. Further research is needed on roller coaster related deaths resulting from intracranial hemorrhages and cardiac problems. PMID:16203841

  12. Head motions while riding roller coasters: implications for brain injury.

    Science.gov (United States)

    Pfister, Bryan J; Chickola, Larry; Smith, Douglas H

    2009-12-01

    The risk of traumatic brain injury (TBI) while riding roller coasters has received substantial attention. Case reports of TBI around the time of riding roller coasters have led many medical professionals to assert that the high gravitational forces (G-forces) induced by roller coasters pose a significant TBI risk. Head injury research, however, has shown that G-forces alone cannot predict TBI. Established head injury criterions and procedures were employed to compare the potential of TBI between daily activities and roller coaster riding. Three-dimensional head motions were measured during 3 different roller coaster rides, a pillow fight, and car crash simulations. Data was analyzed and compared with published data, using similar analyses of head motions. An 8.05 m/s car crash lead to the largest head injury criterion measure of 28.1 and head impact power of 3.41, over 6 times larger than the roller coaster rides of 4.1 and 0.36. Notably, the linear and rotational components of head acceleration during roller coaster rides were milder than those induced by many common activities. As such, there appears to be an extremely low risk of TBI due to the head motions induced by roller coaster rides.

  13. On the Stability of a Bicycle on Rollers

    Science.gov (United States)

    Cleary, Patricia A.; Mohazzabi, Pirooz

    2011-01-01

    Riding a bicycle on the newest form of indoor training, rollers, presents a unique experiment on bicycle stability. The stability factors eliminated by riding on rollers are discussed in terms of refined handling and control of the centre of mass on a bicycle. This paper is intended for undergraduate physics majors as well as any other general…

  14. 49 CFR 215.117 - Defective roller bearing adapter.

    Science.gov (United States)

    2010-10-01

    ... ADMINISTRATION, DEPARTMENT OF TRANSPORTATION RAILROAD FREIGHT CAR SAFETY STANDARDS Freight Car Components Suspension System § 215.117 Defective roller bearing adapter. A railroad may not place or continue in service a car, if the car has a roller bearing adapter that is— (a) Cracked or broken; (b) Not in its...

  15. 49 CFR 215.115 - Defective roller bearing.

    Science.gov (United States)

    2010-10-01

    ..., DEPARTMENT OF TRANSPORTATION RAILROAD FREIGHT CAR SAFETY STANDARDS Freight Car Components Suspension System § 215.115 Defective roller bearing. (a) A railroad may not place or continue in service a car, if the car has— (1) A roller bearing that shows signs of having been overheated as evidenced by—...

  16. Design algorithm for generatrix profile of cylindrical crowned rollers

    Directory of Open Access Journals (Sweden)

    Creţu Spiridon

    2017-01-01

    Full Text Available The cross-section of roller profile controls the pressure distribution in the contact area and radically affects the roller bearings basic dynamic load rating and rating lives. Today the most used roller profiles are the logarithmic profile and cylindrical-crowned (ZB profile. The logarithmic profile has a continuous evolution with no discontinuities till the intersection with the end fillet while ZB profile has two more discontinuities at the intersections points between the crowning circle and straight line generatrix. Using a semianalytical method, a numerical study has been carried out to find the optimum ZB profile for rollers incorporated in cylindrical rollers bearings. The basic reference rating life (L10_r has been used as optimization criterion.

  17. Neurologic complication after a roller coaster ride.

    Science.gov (United States)

    Sa Leitao, Davi; Mendonca, Dercio; Iyer, Harish; Kao, Cheng-Kai

    2012-01-01

    Neurologic complications after roller coaster rides are uncommon but potentially catastrophic. Physicians should have a high index of suspicion and prompt appropriate investigation. A 22-year-old healthy African American man presented with a 2-day history of constant occipital headache associated with vertigo, nausea, vomiting, and ambulatory dysfunction. Physical examination showed gait ataxia, slight dysmetria, and vertical nystagmus. Magnetic resonance imaging (MRI) of the brain showed early subacute ischemic infarct in the right cerebellum in the distribution of the right posterior inferior cerebellar artery. Magnetic resonance angiography of the neck showed focal dissection of the right vertebral artery at C1 through C2 level. On subsequent questioning, the patient recollected riding a roller coaster 2 weeks before the onset of symptoms. Anticoagulation with heparin was started, and the patient was bridged to oral warfarin. After a 5-day uneventful hospital course, symptoms improved and patient was discharged on oral anticoagulation. Cervicocephalic arterial dissections after roller coaster rides are rarely described in literature. The acceleration and abrupt changes of direction might lead to indirect trauma that is applied to mobile portions of the cervicocephalic arteries leading to intimal tears. Magnetic resonance angiography combined with axial T1-weighted cervical MRI is preferred because it is a high-sensitive, noninvasive test. The rationale for the use of anticoagulants or antiplatelets in patients with cervicocephalic arterial dissection is to prevent early recurrence and infarction. However, a meta-analysis failed to show significant difference in the rates of disability or death between both groups. Therefore, the decision for medical treatment should be made in a case-by-case basis.

  18. Kinematics and Dynamics of Roller Chain Drives

    DEFF Research Database (Denmark)

    Fuglede, Niels

    with a clear derivation of the seating and release configurations, as well as the driven sprocket angular position, velocity and discontinuous acceleration. The approximate analysis allows for simple expressions describing the seating and release configurations and shows the influence of main design parameters...... is presented, which also allows for exact sprocket center positions for a chain with a given number of links. Results show that the total chain wrapping length varies periodically with the tooth frequency. These results are of practical importance to both the design, installation and operation of roller chain...

  19. Comparison of a Vibrating Foam Roller and a Non-vibrating Foam Roller Intervention on Knee Range of Motion and Pressure Pain Threshold: A Randomized Controlled Trial.

    Science.gov (United States)

    Cheatham, Scott W; Stull, Kyle R; Kolber, Morey J

    2017-08-08

    The use of foam rollers to provide soft-tissue massage has become a common intervention among health and fitness professionals. Recently, manufacturers have merged the science of vibration therapy and foam rolling with the development of vibrating foam rollers. To date, no peer reviewed investigations have been published on this technology. The purpose of this study was to compare the effects of a vibrating roller and non-vibrating roller intervention on prone knee flexion passive range of motion (ROM) and pressure pain thresholds (PPT) of the quadriceps musculature. Forty-five recreationally active adults were randomly allocated to one of three groups: vibrating roller, non-vibrating roller, and control. Each roll intervention lasted a total of 2 minutes. The control group did not roll. Dependent variables included prone knee flexion ROM and PPT measures. Statistical analysis included parametric and non-parametric tests to measure changes among groups. The vibrating roller demonstrated the greatest increase in PPT (180kPa, pvibrating roller (112kPa, pcontrol (61kPa, pvibrating roller demonstrated the greatest increase in ROM (7 degrees, pvibrating roller (5 degrees, pcontrol (2 degrees, pvibrating and non-vibrating roller (p=.03) and vibrating roller and control (pvibrating roller and control (pvibrating and non-vibrating roller (p=.31). A significant difference was found between the vibrating roller and control group (pvibrating roller and control (pvibrating roller may increase an individual's tolerance to pain greater than a non-vibrating roller. This investigation should be considered exploratory and a starting point for future research on this technology.

  20. Elasto-plastic contact between rollers

    Science.gov (United States)

    Chu, Kunliang; Li, Penghui

    1991-12-01

    Knowledge of the three-dimensional contact stress between roller and rolling road for a strain- hardening material in an elasto-plastic state is limited, to say the least. Mathematical analyses of stress for this problem meet with extreme difficulties. Therefore, experimental approaches are desirable. The experimental elasto-plastic stress analysis method proposed by A. R. Hunter is extended in this investigation. The model material is epoxy resin, which exhibits a frozen nonlinear effective stress-strain behavior similar to that of bearing steel when subjected to a thermal cycle whose maximum temperature is significantly less than the critical temperature of the material. This effective stress-strain curve and an effective birefringence- stress curve were obtained by subjecting uniaxial tensile specimens to constant stress and the appropriate thermal cycle. Then the model was subjected to the same thermal cycle and a uniform distributed load that would develop a plastic zone. The stress distributions on the contact surface and the plastic-zone expansion law were obtained from photomechanical analysis of the slices removed from the model. Several important conclusions were summed up that would greatly improve the roller bearing design.

  1. ELASTOHYDRODYNAMIC LUBRICATION OF LOGARITHMIC PROFILE ROLLER CONTACTS

    Institute of Scientific and Technical Information of China (English)

    2001-01-01

    An account of numerical solutions to the isothermal and flooded elastohydrodynamic lubrication(EHL)of a logarithmic profile roller, which is rolling over a flat plane,is givenThe analysis takes account of sidew ays flow of lubricant in the inlet region of the contactWhen the results are p resented in suitable nondimensional groups,it is shown that more uniformly pre ssure and shape of the film distributing in axial direction is taken place under light loadingAs the increase of the load,the end closure is displayed and the oil pressure rises sharply at the endsThe seal action formed by the end closu re makes the film thickness a littleAnd the minimum film thickness is transfer red from the central to the ends and the value is reduced rapidlyAs the increa se of the speed,the end closure becomes much seriousThe optimum crowning value obtained in EHL state is larger than the design value obtained in elastostatic contact state for the same working conditionsIn order to verify the correctnes s of theory,optical interferometry is applied to measure the oil film thickness between a logarithmic profiled roller and a glass plate under pure rolling condi tionsIt is found the agreement between numerical solutions and experiments is very good

  2. 3000-HP Roller Gear Transmission Development Program. Volume 5. Aircraft Tiedown Testing

    Science.gov (United States)

    1975-07-01

    54 8 5-Hour Break-in Spectrum . a . . . . . . 74 9 Endurance Test, 10-Hour Cycle . . . . . . 76 10 5-Hour Brak -in Test Power Levels . . . . 81...Roller Srface, First-Row Pinion As a result of insufficient blending of the first-row pinion roller radius serial number 69, the sun gear exhibited a...first- row pinion rollers. This was attributable to insuffi- cient blending of the roller crown on the mating second-row gear roller. 2. The spherical

  3. Modeling of electro-statically actuated two-axis (tip-tilt) MEMS torsion micro-mirrors for laser beamsteering

    Science.gov (United States)

    Edwards, C. L.; Boone, B. G.; Levine, W. S.; Davis, C. C.

    2007-04-01

    The availability of recently developed MEMS micro-mirror technology provides an opportunity to replace macro-scale actuators for free-space laser beamsteering in lidar and communication systems. Such an approach is under investigation at the Johns Hopkins University Applied Physics Laboratory for use on space-based platforms. Precision modeling of mirror pointing and its dynamics are critical to optimal design and control of MEMS beamsteerers. Beginning with Hornbeck's torque approach, this paper presents a first-principle, analytically closed-form torque model for an electro-statically actuated two-axis (tip-tilt) MEMS structure. An Euler dynamic equation formulation describes the gimbaled motion as a coupled pair of damped harmonic oscillators with a common forcing function. Static physical parameters such as MEMS mirror dimensions, facet mass, and height are inputs to the model as well as dynamic harmonic oscillator parameters such as damping and restoring constants fitted from measurements. A Taylor series expansion of the torque function provides valuable insights into basic one dimensional as well as two dimensional MEMS behavior, including operational sensitivities near "pull-in." The model also permits the natural inclusion and analysis of pointing noise sources such as electrical drive noise, platform vibration, and molecular Brownian motion. MATLAB and SIMULINK simulations illustrate performance sensitivities, controllability, and physical limitations, important considerations in the design of optimal pointing systems.

  4. A generalized electrostatic micro-mirror (GEM) model for a two-axis convex piecewise linear shaped MEMS mirror

    Science.gov (United States)

    Edwards, C. L.; Edwards, M. L.

    2009-05-01

    MEMS micro-mirror technology offers the opportunity to replace larger optical actuators with smaller, faster ones for lidar, network switching, and other beam steering applications. Recent developments in modeling and simulation of MEMS two-axis (tip-tilt) mirrors have resulted in closed-form solutions that are expressed in terms of physical, electrical and environmental parameters related to the MEMS device. The closed-form analytical expressions enable dynamic time-domain simulations without excessive computational overhead and are referred to as the Micro-mirror Pointing Model (MPM). Additionally, these first-principle models have been experimentally validated with in-situ static, dynamic, and stochastic measurements illustrating their reliability. These models have assumed that the mirror has a rectangular shape. Because the corners can limit the dynamic operation of a rectangular mirror, it is desirable to shape the mirror, e.g., mitering the corners. Presented in this paper is the formulation of a generalized electrostatic micromirror (GEM) model with an arbitrary convex piecewise linear shape that is readily implemented in MATLAB and SIMULINK for steady-state and dynamic simulations. Additionally, such a model permits an arbitrary shaped mirror to be approximated as a series of linearly tapered segments. Previously, "effective area" arguments were used to model a non-rectangular shaped mirror with an equivalent rectangular one. The GEM model shows the limitations of this approach and provides a pre-fabrication tool for designing mirror shapes.

  5. 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.

  6. A New Physical Parameter Identification Method for Two-Axis On-Road Vehicles: Simulation and Experiment

    Directory of Open Access Journals (Sweden)

    Minyi Zheng

    2015-01-01

    Full Text Available A new physical parameter identification method for two-axis on-road vehicle is presented. The modal parameters of vehicle are identified by using the State Variable Method. To make it possible to determine the matrices M, C, and K of the vehicle, a known mass matrix ΔM is designed to add into the vehicle in order to increase the number of equations ensuring that the number of equations is more than the one of unknowns. Therefore, the physical parameters of vehicle can be estimated by using the least square method. To validate the presented method, a numerical simulation example and an experiment example are given in this paper. The numerical simulation example shows that the largest of absolute value of percentage error is 1.493%. In the experiment example, a school bus is employed in study for the parameter identification. The simulation result from full-car model with the estimated physical parameters is compared with the test result. The agreement between the simulation and the test proves the effectiveness of the proposed estimation method.

  7. 5 V Compatible Two-Axis PZT Driven MEMS Scanning Mirror with Mechanical Leverage Structure for Miniature LiDAR Application.

    Science.gov (United States)

    Ye, Liangchen; Zhang, Gaofei; You, Zheng

    2017-03-05

    The MEMS (Micro-Electronical Mechanical System) scanning mirror is an optical MEMS device that can scan laser beams across one or two dimensions. MEMS scanning mirrors can be applied in a variety of applications, such as laser display, bio-medical imaging and Light Detection and Ranging (LiDAR). These commercial applications have recently created a great demand for low-driving-voltage and low-power MEMS mirrors. However, no reported two-axis MEMS scanning mirror is available for usage in a universal supplying voltage such as 5 V. In this paper, we present an ultra-low voltage driven two-axis MEMS scanning mirror which is 5 V compatible. In order to realize low voltage and low power, a two-axis MEMS scanning mirror with mechanical leverage driven by PZT (Lead zirconate titanate) ceramic is designed, modeled, fabricated and characterized. To further decrease the power of the MEMS scanning mirror, a new method of impedance matching for PZT ceramic driven by a two-frequency mixed signal is established. As experimental results show, this MEMS scanning mirror reaches a two-axis scanning angle of 41.9° × 40.3° at a total driving voltage of 4.2 Vpp and total power of 16 mW. The effective diameter of reflection of the mirror is 2 mm and the operating frequencies of two-axis scanning are 947.51 Hz and 1464.66 Hz, respectively.

  8. Development of small bore, high speed tapered roller bearing

    Science.gov (United States)

    Morrison, F. R.; Gassel, S. S.; Bovenkerk, R. L.

    1981-01-01

    The performance of four rolling bearing configurations for use on the input pinion shaft of a proposed commercial helicopter transmission was evaluated. The performance characteristics of a high speed tapered roller bearing operating under conditions comparable to those existing at this input pinion shaft were defined. The tapered roller bearing shaft support configuration was developed for the gearbox using commercially available bearing designings. The configuration was optimized and interactive thermomechanically system analyzed. Automotive pinion quality tapered roller bearings were found to be reliable under load and speed conditions in excess of those anticipated in the helicopter transmission. However, it is indicated that the elastohydrodynamic lubricant films are inadequate.

  9. Roller-chain Drives Mechanics using Multibody Dynamics Tools

    DEFF Research Database (Denmark)

    Ambrosio, Jorge A. C.; Hansen, John Michael

    1999-01-01

    An integrated model for the simulation of roller-chain drives based on a multibody dynamics methodology is presented here in order to describeits complex dynamic behavior. The chain is modeled by masses lumped at the roller locations and connected by translational spring-damper elements in order...... to take into account the elastic flexibility of the chain and the energy dissipation at the joints. The driver and driven sprockets are modeled as rigid bodies that can be repositioned during the analysis in order to simulate automatic tensioners or out-of-balanceshafts. The problem of the rollers...

  10. Chronic subdural haematoma after riding a roller coaster.

    Science.gov (United States)

    Yamakami, Iwao; Mine, Seiichiro; Yamaura, Akira; Fukutake, Toshio

    2005-01-01

    We report a 20-year-old man who developed a chronic subdural haematoma (CSDH) after riding a "giant" roller coaster. The patient had a past history of a subdural hygroma, diagnosed six weeks after a motorcycle accident. Three months after this accident, he rode on a roller coaster, but suffered no direct head trauma during the ride. Three weeks later, he developed a CSDH requiring surgical evacuation. Roller coaster riding, associated with high velocities and extreme acceleration/deceleration forces is a modern cause of CSDH in the young, which may be increasing due to ever-faster rides.

  11. A Calculation Method of Profile Error Influenced by Tool Error for Two-Axis Coordinated CNC Machining of a Spatial Barrel-Cam

    Institute of Scientific and Technical Information of China (English)

    2001-01-01

    Taking the CNC machining for the spatial barrel-cam with rectilinear translating and a conical roller follower as an example, the calculation method and the law of the profile error △n influenced by the tool error AR is given.

  12. Intelligent compaction theory of high roller compacted concrete dam

    Institute of Scientific and Technical Information of China (English)

    Liu Donghai

    2012-01-01

    The concept and realization process of intelligent compaction for the construction of high roller compacted concrete dam were presented, as well as the theory of monitoring and intelligent feedback control. Based on the real-time analysis of the compaction index, a multiple regression model of the dam compactness was established and a realime estimation method of compaction quality for the entire work area of roller compacted concrete dam was proposed finally. The adaptive adjustment of the roiling process parameters was achieved, with the speed, the exciting force, the roller pass and the compaction thickness meeting the standards during the whole construction process. As a result, the compaction quality and construction efficiency can be improved. The research provides a new way for the construction quality control of roller compacted concrete dam.

  13. Comparison between the Needle and Roller Electrospinning of Polyvinylbutyral

    Directory of Open Access Journals (Sweden)

    F. Yener

    2012-01-01

    Full Text Available The effect of the concentration of polyvinylbutyral solution on the process throughput and fibre properties was studied in needle and roller electrospinning. Whereas the polymer throughput is an optional independent parameter in needle electrospinning, it is a dependent parameter that is affected by both the material and process parameters in roller electrospinning. Polymer throughput increases considerably with an increasing concentration of polymer solutions in roller electrospinning. The properties of the nanofibers and the quality of the nanofiber layers were also studied. Fibre diameters increase with an increasing concentration in both techniques. Fibre diameters produced by needle electrospinning are smaller than those produced by roller electrospinning. The distribution of fibre diameters is rather narrow and not significantly dependent on the concentration of solutions in either technique.

  14. Vibratory behaviors of Jeffcott system on cylindrical roller bearings

    Institute of Scientific and Technical Information of China (English)

    Hao WU; Jianwen WANG; Qi AN

    2009-01-01

    A Jeffcott rotor system on cylindrical roller beatings is studied in detail. Its critical speed is calculated by a new calculation method with roller bearing stiffness and damping. The influences of beating parameters, such as the roller length, rotor mass, distance between the bearings and the kinematics viscosity of lubrication on the system critical speed are numerically studied, and the influences of an oil film and damping on the critical speed are also studied. Regular curves of the relationship between the geometric parameters and the system critical speed are obtained. The results show that with increasing roller length and radial load, the critical speed increases; and with increasing rotor mass and the distance between the beatings and the kinematics viscosity, the critical speed decreases. This means that an oil film will decrease the critical rotational speed of the rotor system.

  15. EVALUATION OF A LOW FRICTION - HIGH EFFICIENCY ROLLER BEARING ENGINE

    Energy Technology Data Exchange (ETDEWEB)

    Kolarik, Robert V. II; Shattuck, Charles W.; Copper, Anthony P.

    2009-06-30

    This Low Friction (High Efficiency Roller Bearing) Engine (LFE) report presents the work done by The Timken Company to conduct a technology demonstration of the benefits of replacing hydrodynamic bearings with roller bearings in the crankshaft and camshaft assemblies of an internal combustion engine for the purpose of collecting data sufficient to prove merit. The engines in the present study have been more extensively converted to roller bearings than any previous studies (40 needle roller bearings per engine) to gain understanding of the full potential of application of bearing technology. The project plan called for comparative testing of a production vehicle which was already respected for having demonstrated low engine friction levels with a rollerized version of that engine. Testing was to include industry standard tests for friction, emissions and fuel efficiency conducted on instrumented dynamometers. Additional tests for fuel efficiency, cold start resistance and other measures of performance were to be made in the actual vehicle. Comparative measurements of noise, vibration and harshness (NVH), were planned, although any work to mitigate the suspected higher NVH level in the rollerized engine was beyond the scope of this project. Timken selected the Toyota Avalon with a 3.5L V-6 engine as the test vehicle. In an attempt to minimize cost and fabrication time, a ‘made-from’ approach was proposed in which as many parts as possible would be used or modified from production parts to create the rollerized engine. Timken commissioned its test partner, FEV Engine Technology, to do a feasibility study in which they confirmed that using such an approach was possible to meet the required dimensional restrictions and tolerances. In designing the roller bearing systems for the crank and cam trains, Timken utilized as many production engine parts as possible. The crankshafts were produced from production line forgings, which use Timken steel, modified with special

  16. Optimization analysis on assembly interference of cylindrical roller bearings

    Directory of Open Access Journals (Sweden)

    Zhen-huan Ye

    2015-07-01

    Full Text Available Distribution of loads and contact stress has a great influence on fatigue life of bearings. In view of the fact that the nonload area is ubiquitous in cylindrical roller bearings, there is a method for prolonging the fatigue life design by adjusting the working clearance of cylindrical roller bearings. In this article, optimization model of fatigue life of cylindrical roller bearings is developed with a quasi-dynamic method and calculated method of bearing life based on micro-area contact, considering the effect of assembly interference, temperature rise, and high-speed centrifugation. Aiming to the different geometry parameters and operating parameters of bearings, the effects of assembly interference on bearing fatigue life are discussed. The results show that the optimum fatigue life of roller bearings is achieved at negative working clearance with the loads distributed evenly within half ring. The optimum working clearance of roller bearings is not influenced by radial load. But with the increase in pitch diameter or decrease in rolling elements, the optimum assembly interference increases, and accelerating revolution of roller bearings will increase the optimum assembly interference as well.

  17. Analysis of roller pen inks by capillary zone electrophoresis

    Institute of Scientific and Technical Information of China (English)

    ZHAO Pengcheng; WANG Yanji; XU Yuanyuan; YAO Lijuan

    2007-01-01

    The analysis of roller pen inks has become more and more important in fraudulent document examination because of the extensive use of roller pens in financial documents.Capillary electrophoresis with powerful resolution was applied for the analysis of roller pen inks.The experiment focused on the optimization of the separation of the extract from commercially available roller pen entries.A better separation electropherogram was obtained when a 20 mM borate buffer at pH 8.5 and a fused silica capillary with an inner diameter of 100 μm with a total length of 47 (40 cm to the detector window)were used.Five inks from roller pens of different manufacturers and countries were analyzed,and their electropherograms showed that most patterns are distinctly different from each other.Capillary with inner diameter of 100 μm increased the intensity of determination;therefore,color dyes were identified in the visible range and were able to provide more information for comparing types of roller pen inks.

  18. A study on rheological characteristics of roller milled fenugreek fractions.

    Science.gov (United States)

    Sakhare, Suresh D; Inamdar, Aashitosh A; Prabhasankar, P

    2016-01-01

    Fenugreek seeds were fractionated by roller milling to get various fractions. The roller milled fractions and whole fenugreek flour (WFF) were evaluated for the flow behavior and time-dependent flow properties using a rotational viscometer at the temperatures of 10-60 (0)C. The samples subjected to a programmed shear rate increase linearly from 0 to 300 s(-1) in 3 min and successive decrease linearly shear rate from 300 s(-1) to 0 in 3 min. The roller milled fractions and WFF paste exhibited non-Newtonian pseudoplastic behavior. Difference in hysteresis loop area was observed among the roller milled fractions and WFF, being more noticeable at lower temperatures. Power law and Casson models were used to predict flow properties of samples. The power law model described well the flow behavior of the roller milled fractions and WFF at temperatures tested. Except flour (FL) fraction, consistency coefficient, m, increased with the temperature both in the forward and backward measurements. The roller milled fractions and WFF exhibited rheopectic behavior that increased viscosity with increasing the shear speed and the temperature. For all the sample tested, initial shear stress increased with increase in shear rate and temperature.

  19. Parametric sensitivity of two axis models for turbo-generators; Sensibilidad parametrica de modelos de dos ejes para turbogeneradores

    Energy Technology Data Exchange (ETDEWEB)

    Morales Castorena, Armando

    2003-06-15

    The results of parameter sensitivity studies performed on two axis equivalent circuits (TAECs) of synchronous machines are presented in this thesis. The circuits consist of inductive and resistive elements. Their connectivity represents the magnetic and electric coupling inside the machine as well as its energy losses. Two equivalent circuits are needed to represent the machine, one for the direct axis (d) and another for the quadrature axis (q), because it is modeled under the two-axis reaction theory of Park. Parameter values have been identified in advance, using standstill frequency response tests (SSFR). This response was calculated using a finite element model of a turbine generator. The parameter identification is achieved by applying an optimization process based on a hybrid algorithm (stochastic-deterministic). The fitness function is defined as the square of the differences between magnitudes and phase angles of the frequency response functions of the TAECs and of the turbogenerator. This procedure yields the TAECs that better fit the frequency response of the machine. Thus, the circuits identified are considered good models of the machine and they can be applied for digital simulation of dynamic behavior. The identified TAECs are the basis of the parameter sensitivity studies reported here. These studies consist of doing very small variations to parameter values, and to calculate the new value of the fitness function. The ratio between the change of the fitness function to the change in parameter value is called sensitivity of the fitness function, or simply, sensitivity function. Its magnitude indicates which parameter has a greater or lesser influence on the fitness function. If the fitness function is very sensitive to a particular parameter, then the rightness of the identified value of that parameter may be in doubt. With this information it is possible to establish the reliability of the identification process and to exert corrective actions. It is

  20. Significant changes in the skin microbiome mediated by the sport of roller derby

    Directory of Open Access Journals (Sweden)

    James F. Meadow

    2013-03-01

    Full Text Available Diverse bacterial communities live on and in human skin. These complex communities vary by skin location on the body, over time, between individuals, and between geographic regions. Culture-based studies have shown that human to human and human to surface contact mediates the dispersal of pathogens, yet little is currently known about the drivers of bacterial community assembly patterns on human skin. We hypothesized that participation in a sport involving skin to skin contact would result in detectable shifts in skin bacterial community composition. We conducted a study during a flat track roller derby tournament, and found that teammates shared distinct skin microbial communities before and after playing against another team, but that opposing teams’ bacterial communities converged during the course of a roller derby bout. Our results are consistent with the hypothesis that the human skin microbiome shifts in composition during activities involving human to human contact, and that contact sports provide an ideal setting in which to evaluate dispersal of microorganisms between people.

  1. Dropout Reasons in Iranian Youth Roller Skaters

    Directory of Open Access Journals (Sweden)

    Hosein H E Y D A R I

    2014-12-01

    Full Text Available The main drop - out reasons from the sport of roller skating amongst Iranian youth skaters has been examined. A questionnaire with 53 items (adopted from Enoksen, 2011 representing seven subscales namel y: training factors and facilities, executive factors and team, education and work obligations, motivational aspects, social - cultural environment, choice of other sport activities and interests and economic factors was especially developed for this researc h. Responses were measured on a Likert scale ranging from “strongly disagree” to “strongly agree” in relation to each statement. In all 11 2 skaters predominantly male (mean age 17.1, SD = 1.63 with a mean = 5.43 years of experience (SD = 2.92 that had di scontinued in the past two years completed the questionnaire. Results of one sample t - tests showed that all factors expect “social - cultural environment” are significant indicators for drop out from skating with “economical factors” scoring the highest rank ing. Correlational analysis showed that younger participants agree more strongly th at “executive factors and team” and “education and work obligations” were the best predictors of drop out. Those with fewer years of experience considered “training factors and facilities”, “motivational aspects and social and cultural environment” as more likely reasons for quitting. Implications of the findings are discussed.

  2. Underviserens roller fra centrum til periferi

    Directory of Open Access Journals (Sweden)

    Hanne Leth Andersen

    2006-05-01

    Full Text Available

    Første gang publiceret i UNEV nr. 7: E-læring i sprogfag, juni 2006, red. Signe Hvid Maribo og Ole Lauridsen. ISSN 1603-5518.

    Artiklen "Underviserens roller fra centrum til periferi" sætter fokus på færdighedstræning, herunder ordforråd og grammatik, og på undervisningsdifferentiering ved inddragelse af digitale medier i undervisningen. Det er oplagt, at underviseren indtager en mere perifer, men ikke mindre væsentlig rolle i fremtidens lærings-orienterede (sprogundervisning, mens den lærende indtager centrum i forhold til egne læreprocesser. Der gives konkrete eksempler på, hvordan man kan arbejde konstruktivt med mundtlig dialogtræning ved at inddrage forskellige elektroniske redskaber og metoder samt hvordan man kan arbejde med forskellige typer af korpora i fremmedsprogs-undervisningen til arbejde med ordforråd, grammatik og tekstforståelse.

  3. Temperature distribution and scuffing of tapered roller bearing

    Science.gov (United States)

    Wang, Ailin; Wang, Jiugen

    2014-11-01

    In the field of aerospace, high-speed trains and automobile, etc, analysis of temperature filed and scuffing failure of tapered roller bearings are more important than ever, and the scuffing failure of elements of such rolling bearings under heavy load and high speed still cannot be effectively predicted yet. A simplified model of tapered roller bearings consisted of one inner raceway, one outer raceway and a tapered roller was established, in which the interaction of several heat sources is ignored. The contact mechanics model, temperature model and model of scuffing failure are synthesized, and the corresponding computer programs are developed to analyze the effects of bearings parameters, different material and operational conditions on thermal performance of bearings, and temperature distribution and the possibility of surface scuffing are obtained. The results show that load, speed, thermal conductivity and tapered roller materials influence temperature rise and scuffing failure of bearings. Ceramic material of tapered roller results in the decrease of scuffing possibility of bearings to a high extent than the conventional rolling bearing steel. Compared with bulk temperature, flash temperature on the surfaces of bearing elements has a little influence on maximum temperature rise of bearing elements. For the rolling bearings operated under high speed and heavy load, this paper proposes a method which can accurately calculate the possibility of scuffing failure of rolling bearings.

  4. Pressure pulsation in roller pumps: a validated lumped parameter model.

    Science.gov (United States)

    Moscato, Francesco; Colacino, Francesco M; Arabia, Maurizio; Danieli, Guido A

    2008-11-01

    During open-heart surgery roller pumps are often used to keep the circulation of blood through the patient body. They present numerous key features, but they suffer from several limitations: (a) they normally deliver uncontrolled pulsatile inlet and outlet pressure; (b) blood damage appears to be more than that encountered with centrifugal pumps. A lumped parameter mathematical model of a roller pump (Sarns 7000, Terumo CVS, Ann Arbor, MI, USA) was developed to dynamically simulate pressures at the pump inlet and outlet in order to clarify the uncontrolled pulsation mechanism. Inlet and outlet pressures obtained by the mathematical model have been compared with those measured in various operating conditions: different rollers' rotating speed, different tube occlusion rates, and different clamping degree at the pump inlet and outlet. Model results agree with measured pressure waveforms, whose oscillations are generated by the tube compression/release mechanism during the rollers' engaging and disengaging phases. Average Euclidean Error (AEE) was 20mmHg and 33mmHg for inlet and outlet pressure estimates, respectively. The normalized AEE never exceeded 0.16. The developed model can be exploited for designing roller pumps with improved performances aimed at reducing the undesired pressure pulsation.

  5. Temperature Distribution and Scuffing of Tapered Roller Bearing

    Institute of Scientific and Technical Information of China (English)

    WANG Ailin; WANG Jiugen

    2014-01-01

    In the field of aerospace, high-speed trains and automobile, etc, analysis of temperature filed and scuffing failure of tapered roller bearings are more important than ever, and the scuffing failure of elements of such rolling bearings under heavy load and high speed still cannot be effectively predicted yet. A simplified model of tapered roller bearings consisted of one inner raceway, one outer raceway and a tapered roller was established, in which the interaction of several heat sources is ignored. The contact mechanics model, temperature model and model of scuffing failure are synthesized, and the corresponding computer programs are developed to analyze the effects of bearings parameters, different material and operational conditions on thermal performance of bearings, and temperature distribution and the possibility of surface scuffing are obtained. The results show that load, speed, thermal conductivity and tapered roller materials influence temperature rise and scuffing failure of bearings. Ceramic material of tapered roller results in the decrease of scuffing possibility of bearings to a high extent than the conventional rolling bearing steel. Compared with bulk temperature, flash temperature on the surfaces of bearing elements has a little influence on maximum temperature rise of bearing elements. For the rolling bearings operated under high speed and heavy load, this paper proposes a method which can accurately calculate the possibility of scuffing failure of rolling bearings.

  6. Selection and Calculation of Optimum Generatrix of Rolling contacts for Roller Bearings,

    Science.gov (United States)

    the rollers. The reason for the concentration of contact stresses at the edges of cylindrical rollers is the edge effect , a sharp increase in...inaccuracy in bearing manufacture. A new form of generatrix is suggested produced with large radius camber and elements decreasing the influence of the edge ... effect , considering the actual operating conditions of circles and rollers and providing increased bearing durability in bearings with rollers having rectangular generatrix.

  7. A Solution of Drawing Straightening Roller Curve by Conjugate Revolving Quadric Theory

    Institute of Scientific and Technical Information of China (English)

    DU Xiaozhong; WANG Jianmei; HUANG Qingxue; SUN Binyu

    2006-01-01

    Based on the theory of conjugate revolving quadric theory, the analytic method of calculating the straightening roller curve in the procedure of straightening the bar has been given. Meanwhile, the equations, which describe roller curve and the longitudinal section, are given and simulated in computer. A brief method of designing and drawing the straightening roller curve is introduced.

  8. Improving the compaction properties of roller compacted calcium carbonate.

    Science.gov (United States)

    Bacher, C; Olsen, P M; Bertelsen, P; Kristensen, J; Sonnergaard, J M

    2007-09-05

    The effects of roller compaction process parameters, morphological forms of calcium carbonate and particle size of sorbitol on flow, compaction and compression properties were investigated. The morphology of the calcium carbonate and the sorbitol particle size were more influential on the compaction properties than the settings of the roller compactor. The roller compaction process was demonstrated to be robust and stable in regard to flowability and compactibility. The flowability of the granules was improved adequately to facilitate compression in a production scale rotary tablet press. By adding sorbitol to the calcium carbonate, the compressibility - characterized by the Walker coefficient W(ID) - and the compactibility C(P) were improved considerably. A correlation between the consolidation characteristics was demonstrated. Compactibility data from the compaction simulator correlated with the tablet press for two of the calcium carbonates, the cubic form and the ground quality.

  9. The roller coaster flight strategy of bar-headed geese conserves energy during Himalayan migrations

    Science.gov (United States)

    Bishop, C.M.; Spivey, R.J.; Hawkes, L. A.; Batbayar, N.; Chua, B.; Frappell, P.B.; Milsom, W.K.; Natsagdorj, T.; Newman, S.H.; Scott, G.R.; Takekawa, John Y.; Wikelski, Martin; Butler, Patrick J.

    2015-01-01

    The physiological and biomechanical requirements of flight at high altitude have been the subject of much interest. Here, we uncover a steep relation between heart rate and wingbeat frequency (raised to the exponent 3.5) and estimated metabolic power and wingbeat frequency (exponent 7) of migratory bar-headed geese. Flight costs increase more rapidly than anticipated as air density declines, which overturns prevailing expectations that this species should maintain high-altitude flight when traversing the Himalayas. Instead, a "roller coaster" strategy, of tracking the underlying terrain and discarding large altitude gains only to recoup them later in the flight with occasional benefits from orographic lift, is shown to be energetically advantageous for flights over the Himalayas.

  10. The roller coaster flight strategy of bar-headed geese conserves energy during Himalayan migrations.

    Science.gov (United States)

    Bishop, C M; Spivey, R J; Hawkes, L A; Batbayar, N; Chua, B; Frappell, P B; Milsom, W K; Natsagdorj, T; Newman, S H; Scott, G R; Takekawa, J Y; Wikelski, M; Butler, P J

    2015-01-16

    The physiological and biomechanical requirements of flight at high altitude have been the subject of much interest. Here, we uncover a steep relation between heart rate and wingbeat frequency (raised to the exponent 3.5) and estimated metabolic power and wingbeat frequency (exponent 7) of migratory bar-headed geese. Flight costs increase more rapidly than anticipated as air density declines, which overturns prevailing expectations that this species should maintain high-altitude flight when traversing the Himalayas. Instead, a "roller coaster" strategy, of tracking the underlying terrain and discarding large altitude gains only to recoup them later in the flight with occasional benefits from orographic lift, is shown to be energetically advantageous for flights over the Himalayas.

  11. Rollers in low-head dams - Challenges and solutions

    Science.gov (United States)

    Zamankhan, Piroz

    2012-12-01

    Low-head dams exist in many rivers for the purposes of diverting water for open-channel irrigation and providing power plants with cooling water. Flow over low-head dams is quite complex and dangerous rollers often develop down-stream that tend to trap and submerge floating objects. This paper presents an analysis of the problem based on physical and computational fluid dynamics (CFD) modeling and the result of this analysis in the form of design suggestions intended to diminish the hazards associated with rollers.

  12. Wear of Steel and Ti6Al4V Rollers in Vacuum

    Science.gov (United States)

    Krantz, Timothy L.; Shareef, Iqbal

    2012-01-01

    This investigation was prompted by results of a qualification test of a mechanism to be used for the James Webb Space Telescope. Post-test inspections of the qualification test article revealed some loose wear debris and wear of the steel rollers and the mating Ti6Al4V surfaces. An engineering assessment of the design and observations from the tested qualification unit suggested that roller misalignment was a controlling factor. The wear phenomena were investigated using dedicated laboratory experiments. Tests were done using a vacuum roller rig for a range of roller misalignment angles. The wear in these tests was mainly adhesive wear. The measured wear rates were highly correlated to the misalignment angle. For all tests with some roller misalignment, the steel rollers lost mass while the titanium rollers gained mass indicating strong adhesion of the steel with the titanium alloy. Inspection of the rollers revealed that the adhesive wear was a two-way process as titanium alloy was found on the steel rollers and vice versa. The qualification test unit made use of 440F steel rollers in the annealed condition. Both annealed 440F steel rollers and hardened 440C rollers were tested in the vacuum roller rig to investigate possibility to reduce wear rates and the risk of loose debris formation. The 440F and 440C rollers had differing wear behaviors with significantly lesser wear rates for the 440C. For the test condition of zero roller misalignment, the adhesive wear rates were very low, but still some loose debris was formed

  13. Heat transfer analysis for the roller shell under the condition of periodic thermal shock

    Institute of Scientific and Technical Information of China (English)

    Lihua Zhan; Xiaoqian Li

    2003-01-01

    According to the actual working conditions of roller shell in the process of continuous roll casting, the Fourier heat transfer law is used to conduct the simulating analysis for the temperature distribution of the roller shell under the condition of periodic thermal shock. The temperature variation law inside the roller shell is studied during the process of continuous roll casting, and the steady temperature distributions of the roller shell at different casting velocities have been obtained when the thermal contact conductance between the roller shell and the casting strip is considered.

  14. Numerically Analysed Thermal Condition of Hearth Rollers with the Water-Cooled Shaft

    Directory of Open Access Journals (Sweden)

    A. V. Ivanov

    2016-01-01

    Full Text Available Continuous furnaces with roller hearth have wide application in the steel industry. Typically, furnaces with roller hearth belong to the class of medium-temperature heat treatment furnaces, but can be used to heat the billets for rolling. In this case, the furnaces belong to the class of high temperature heating furnaces, and their efficiency depends significantly on the reliability of the roller hearth furnace. In the high temperature heating furnaces are used three types of watercooled shaft rollers, namely rollers without insulation, rollers with insulating screens placed between the barrel and the shaft, and rollers with bulk insulation. The definition of the operating conditions of rollers with water-cooled shaft greatly facilitates the choice of their design parameters when designing. In this regard, at the design stage of the furnace with roller hearth, it is important to have information about the temperature distribution in the body of the rollers at various operating conditions. The article presents the research results of the temperature field of the hearth rollers of metallurgical heating furnaces. Modeling of stationary heat exchange between the oven atmosphere and a surface of rollers, and between the cooling water and shaft was executed by finite elements method. Temperature fields in the water-cooled shaft rollers of various designs are explored. The water-cooled shaft rollers without isolation, rollers with screen and rollers with bulk insulation, placed between the barrel and the water-cooled shaft were investigated. Determined the change of the thermo-physic parameters of the coolant, the temperature change of water when flowing in a pipe and shaft, as well as the desired pressure to supply water with a specified flow rate. Heat transfer coefficients between the cooling water and the shaft were determined directly during the solution based on the specified boundary conditions. Found that the greatest heat losses occur in the

  15. APPLICATION OF SUB-ELEMENT AND MICRO-ELEMENT IN BEM WITH ROLLER BEARING LOAD

    Institute of Scientific and Technical Information of China (English)

    Shu Xuedao; Xing Xidong

    2004-01-01

    Aiming at the discontinuous traction on contact elements of roller bearing, new concepts of sub- and micro-element are put forward. In the sub-element and micro-element, traction influence coefficient has been modified, which is calculated by the former boundary element method (BEM) with roller bearing load. Hence, three-dimensional distribution of load on roller bearing is calculated accurately. In practice, it has been proved that this method has higher calculation accuracy. An effective numerical method is offered for analyzing load characteristics of roller bearing to improve service longevity of roller bearing and operation efficiency of rolling mill.

  16. Deviation Prevention Ability of Rollers in Continuous Annealing Furnace and Application

    Institute of Scientific and Technical Information of China (English)

    ZHANG Yan; YANG Quan; HE An-rui; YAO Xi-jiang; GUO De-fu

    2012-01-01

    In order to reduce the strip deviation in the practical production procedure in the continuous annealing fur- nace, a dynamic simulation model was built through finite element method (FEM) to conduct the quantification cal- culation of the effect of regular roller contour types on strip deviation. The result reveals that comparing to the flat roller, forward roller contour can prevent the strip deviation to some degree. In terms of prevention ability, double- taper roller is the strongest, single-taper roller and crown roller are less stronger; and more roller contour values raise the prevention ability. Accordingly, optimization method was applied to continuous annealing furnace, and it largely reduced accidents such as strip break and limited speed that are caused by the deviation.

  17. The Physics of the Roller Coaster: Learning Physics through Simulation.

    Science.gov (United States)

    Hannum, Wallace

    2001-01-01

    This instructional design blends a structured learning environment (the physics lesson) with an engaging, playful, simulated environment (roller coaster construction), putting into operation ideas from both cognitive and constructivist theories. Two instructional models are used: a general design model for creating instruction and a lesson design…

  18. Traumatic bilateral ECCA injury in a roller coaster enthusiast.

    Science.gov (United States)

    Stahlfeld, Kurt R; Roozrokh, Hootan C

    2002-07-01

    Vascular and trauma surgeons have seen a marked increase in the incidence of traumatic injury of the ECCA. Making the diagnosis is straightforward, but requires a high index of suspicion. This patient's injury is from hyperextension/flexion trauma that occurred from repetitive rides on roller coasters.

  19. Kinematics of roller chain drives - Exact and approximate analysis

    DEFF Research Database (Denmark)

    Fuglede, Niels; Thomsen, Jon Juel

    2016-01-01

    An exact and approximate kinematic analysis of a roller chain drive modeled as a four-bar mechanism is presented. The span connects the sprockets such that they rotate in the same direction, and the sprocket size, number of teeth, and shaft center distance can be arbitrary. The driven sprocket...

  20. Visualization in Mechanics: The Dynamics of an Unbalanced Roller

    Science.gov (United States)

    Cumber, Peter S.

    2017-01-01

    It is well known that mechanical engineering students often find mechanics a difficult area to grasp. This article describes a system of equations describing the motion of a balanced and an unbalanced roller constrained by a pivot arm. A wide range of dynamics can be simulated with the model. The equations of motion are embedded in a graphical…

  1. Uklare roller i postmoderne organisationer - om ledelse og selvstyrende grupper

    DEFF Research Database (Denmark)

    Visholm, Steen

    2005-01-01

    I denne artikel tages udgangspunkt i en psykoanalytisk tilgang til forståelsen af lederes og ansattes reaktioner på uklare roller i forbindelse med teamorganisering. På baggrund af analysen af en case fra en dansk industrivirksomhed argumenteres i artiklen for, at psykoanalysen vil kunne bidrage ...

  2. The Physics of the Roller Coaster: Learning Physics through Simulation.

    Science.gov (United States)

    Hannum, Wallace

    2001-01-01

    This instructional design blends a structured learning environment (the physics lesson) with an engaging, playful, simulated environment (roller coaster construction), putting into operation ideas from both cognitive and constructivist theories. Two instructional models are used: a general design model for creating instruction and a lesson design…

  3. A self-feeding roller bottle for continuous cell culture.

    Science.gov (United States)

    Berson, R Eric; Friederichs, Goetz

    2008-01-01

    The concept of a self-feeding roller bottle that delivers a continuous supply of fresh media to cells in culture, which is mechanically simplistic and works with existing roller apparatuses, is presented here. A conventional roller bottle is partitioned into two chambers; one chamber contains the fresh culture media reservoir, and the other contains the cell culture chamber. A spiroid of tubing inside the fresh media reservoir acts as a pump when the bottle rotates on its horizontal axis, continuously delivering fresh media through an opening in the partition to the cell culture chamber. The modified bottle proved capable of maintaining steady-state cell densities of a hybridoma cell line over the 10-day period tested, although at lower densities than reached during batch operation due to the continuous volume dilution. Steady-state density proved to be controllable by adjusting the perfusion rate, which changes with the rotation rate of the bottle. Specific antibody production rate is as much as 3.7 times the rate in conventional roller bottles operating with intermittent batch feeding.

  4. Sport selection in under-17 male roller hockey

    NARCIS (Netherlands)

    Coelho-E-Silva, Manuel J.; Vaz, Vasco; Simoes, Filipe; Carvalho, Humberto M.; Valente-Dos-Santos, Joao; Figueiredo, Antonio J.; Pereira, Vanildo; Vaeyens, Roel; Philippaerts, Renaat; Elferink-Gemser, Marije T.; Malina, Robert M.

    2012-01-01

    Characteristics of 32 international and 41 local under-17 (U-17) (14.516.5 years) roller hockey players were considered in the context of discrimination by competitive level using training history, anthropometry, skeletal maturation, and several laboratory and field performance tests. More

  5. Visualization in Mechanics: The Dynamics of an Unbalanced Roller

    Science.gov (United States)

    Cumber, Peter S.

    2017-01-01

    It is well known that mechanical engineering students often find mechanics a difficult area to grasp. This article describes a system of equations describing the motion of a balanced and an unbalanced roller constrained by a pivot arm. A wide range of dynamics can be simulated with the model. The equations of motion are embedded in a graphical…

  6. Sport selection in under-17 male roller hockey

    NARCIS (Netherlands)

    Coelho-E-Silva, Manuel J.; Vaz, Vasco; Simoes, Filipe; Carvalho, Humberto M.; Valente-Dos-Santos, Joao; Figueiredo, Antonio J.; Pereira, Vanildo; Vaeyens, Roel; Philippaerts, Renaat; Elferink-Gemser, Marije T.; Malina, Robert M.

    2012-01-01

    Characteristics of 32 international and 41 local under-17 (U-17) (14.516.5 years) roller hockey players were considered in the context of discrimination by competitive level using training history, anthropometry, skeletal maturation, and several laboratory and field performance tests. More internati

  7. Extrusion Roller Imprinting with a Variotherm Belt Mold

    Directory of Open Access Journals (Sweden)

    Raymond Frenkel

    2014-12-01

    Full Text Available Although many precision fabrication techniques have demonstrated the ability to produce microstructures and micro-devices with sub 100 nm accuracy, we are yet to see a scalable manufacturing process for large-area production. One promising solution to scalable micro- and nanofabrication is thermal roller imprinting. However, existing investigations on thermal roller imprinting revealed poor pattern transfer fidelity, especially for high aspect ratio features. The standard roller imprinting process suffers from the lack of an effective holding and cooling stage so that the adverse effects from the viscoelastic nature of polymers are not managed. To rectify this problem and further improve the production rate, a new extrusion roller imprinting process with a variotherm belt mold is designed, and its prototype was established at a laboratory scale. The process testing results demonstrate that a 30 μm sawtooth pattern can be faithfully transferred to extruded polyethylene film at take-up speeds higher than 10 m/min. The results are promising in that microfeatures or even nanofeatures may be successfully replicated by a robust and scalable industrial process suitable for large-area, continuous production.

  8. 现代圆柱滚子轴承设计%Design of Modem Cylindrical Roller Bearing

    Institute of Scientific and Technical Information of China (English)

    张俊杰; 潘德仁; 王敏

    2000-01-01

    By improving steel material quality,adopting plastic cage,improving rib structure and using crowned rollers,the life and performance of cylindrical roller bearing can be largely increased.The paper introduces the establishment of target function,determination of restrict condition and optimizing design for some parameters such as roller diameter,length,number of roller and the maximum dynamic load rating etc,and emphasizes on statement for crowned desip of roller and selection of cage.

  9. Control Parameters Optimization Based on Co-Simulation of a Mechatronic System for an UA-Based Two-Axis Inertially Stabilized Platform

    Directory of Open Access Journals (Sweden)

    Xiangyang Zhou

    2015-08-01

    Full Text Available This paper presents a method based on co-simulation of a mechatronic system to optimize the control parameters of a two-axis inertially stabilized platform system (ISP applied in an unmanned airship (UA, by which high control performance and reliability of the ISP system are achieved. First, a three-dimensional structural model of the ISP is built by using the three-dimensional parametric CAD software SOLIDWORKS®; then, to analyze the system’s kinematic and dynamic characteristics under operating conditions, dynamics modeling is conducted by using the multi-body dynamics software ADAMS™, thus the main dynamic parameters such as displacement, velocity, acceleration and reaction curve are obtained, respectively, through simulation analysis. Then, those dynamic parameters were input into the established MATLAB® SIMULINK® controller to simulate and test the performance of the control system. By these means, the ISP control parameters are optimized. To verify the methods, experiments were carried out by applying the optimized parameters to the control system of a two-axis ISP. The results show that the co-simulation by using virtual prototyping (VP is effective to obtain optimized ISP control parameters, eventually leading to high ISP control performance.

  10. Control Parameters Optimization Based on Co-Simulation of a Mechatronic System for an UA-Based Two-Axis Inertially Stabilized Platform.

    Science.gov (United States)

    Zhou, Xiangyang; Zhao, Beilei; Gong, Guohao

    2015-08-14

    This paper presents a method based on co-simulation of a mechatronic system to optimize the control parameters of a two-axis inertially stabilized platform system (ISP) applied in an unmanned airship (UA), by which high control performance and reliability of the ISP system are achieved. First, a three-dimensional structural model of the ISP is built by using the three-dimensional parametric CAD software SOLIDWORKS(®); then, to analyze the system's kinematic and dynamic characteristics under operating conditions, dynamics modeling is conducted by using the multi-body dynamics software ADAMS™, thus the main dynamic parameters such as displacement, velocity, acceleration and reaction curve are obtained, respectively, through simulation analysis. Then, those dynamic parameters were input into the established MATLAB(®) SIMULINK(®) controller to simulate and test the performance of the control system. By these means, the ISP control parameters are optimized. To verify the methods, experiments were carried out by applying the optimized parameters to the control system of a two-axis ISP. The results show that the co-simulation by using virtual prototyping (VP) is effective to obtain optimized ISP control parameters, eventually leading to high ISP control performance.

  11. Disentangling migratory routes and wintering grounds of Iberian near-threatened European Rollers Coracias garrulus.

    Directory of Open Access Journals (Sweden)

    Juan Rodríguez-Ruiz

    Full Text Available Long-distance migrants are suffering drastic declines in the last decades. Causes beneath this problem are complex due to the wide spatial and temporal scale involved. We aim to reveal migratory routes, stopover areas, wintering grounds, and migratory strategies for the most southwestern populations of the near-threatened European Roller Coracias garrulus in order to identify conservation key areas for the non-breeding stage of this species. To this end, we used tracking data from seven satellite transmitters fitted to birds breeding in different populations throughout the Iberian Peninsula and four geolocators fitted to individuals in a southeastern Iberian population. Precise satellite data were used to describe daily activity patterns and speed in relation to the main regions crossed during the migration. Individuals from the most southwestern Iberian populations made a detour towards the Atlantic African coast whereas those from northeastern populations followed a straight north-to-south route. We identified important stopover areas in the Sahel belt, mainly in the surroundings of the Lake Chad, and wintering grounds on southwestern Africa farther west than previously reported for the species. Concerning the migratory strategy, satellite data revealed: 1 a mainly nocturnal flying activity, 2 that migration speed depended on the type of crossed habitat, with higher average speed while crossing the desert; and 3 that the migration was slower and lasted longer in autumn than in spring. The studied populations showed weak migratory connectivity, suggesting the confluence of birds from a wide range of breeding grounds in a restricted wintering area. Therefore, we suggest to target on defining precisely key areas for this species and identifying specific threats in them in order to develop an appropriate global conservation programme for the European Roller.

  12. Student investigations of the forces in a roller coaster loop

    Science.gov (United States)

    Pendrill, Ann-Marie

    2013-11-01

    How does the experience of a riding in a roller coaster loop depend on your position in the train? This question has been investigated by first year engineering physics students by using multiple representations of force and motion. Theoretical considerations for a circular loop show that the differences between the forces on a rider in the front, middle or back of the train depend on the ratio between train length and radius of the loop, which can be estimated from a photograph. Numerical computations complement the analysis of a video clip, accelerometer data, and measurements of the time needed for the train to move over the highest point. A roller coaster ride gives striking examples of Newton's laws applied to your own body, and demonstrates that the experience depends on the vector character of velocity and acceleration.

  13. Den danske professionelle fundraiser og de mange roller

    DEFF Research Database (Denmark)

    Vinstrup, Anya Bjørn

    2015-01-01

    Udforskningen af den professionelle fundraiser på de danske universiteter er et forskningsfelt, hvor der endnu kun er meget lidt viden. Organiseringen af fundraisere på de danske universiteter er forskellige med både centrale enheder, decentrale enheder og forskellige kombinationer af disse....... Diskussioner af hvad en fundraisers arbejdsområde, motivation og roller i det hele taget er, danner udgangspunkt for kvantitative og kvalitative analyser. Data er indsamlet via et online spørgeskema sendt til så vidt muligt alle fundraisere på de 8 danske universiteter. Der er undersøgt for statistisk...... vægtningen af de forskellige roller, samt hvorfor man blev fundraiser, og hvad der motiverer en i arbejdet. Det er en grundlæggende eksplorativ analyse, af nogle af de elementer, der er med til at influere valget og organiseringen af arbejdet med professionel fundraising samt ledelsen af de professionelle...

  14. Simulation and Analysis of Roller Chain Drive Systems

    DEFF Research Database (Denmark)

    Pedersen, Sine Leergaard

    formulation for the simulation of the dynamics of roller chain drives using a continuous contact force method is developed in this work. The model of the contact surface between the rollers and sprocket has shown to be an important issue regarding the numerical stability of the simulation program and a model...... with a real tooth profile proves superior to other applied models. With this model it is possible to perform a dynamic simulation of large marine engine chain drives. Through the application of this method, it is shown that the interrelated dynamics of the elements in the chain drive system is captured...... and the contact problem is characterized. The chain drive model is compared with simplified analytical results, while the necessary experimental validation is left for future studies....

  15. Fabrication of Silk Nanofibres with Needle and Roller Electrospinning Methods

    Directory of Open Access Journals (Sweden)

    Nongnut Sasithorn

    2014-01-01

    Full Text Available In this study, silk nanofibres were prepared by electrospinning from silk fibroin in a mixture of formic acid and calcium chloride. A needle and a rotating cylinder were used as fibre generators in the spinning process. The influences of the spinning electrode and spinning parameters (silk concentration and applied voltage on the spinning process, morphology of the obtained fibres, and the production rate of the spinning process were examined. The concentration of the spinning solution influenced the diameter of the silk electrospun fibres, with an increase in the concentration increasing the diameters of the fibres in both spinning systems. The diameters of the electrospun fibres produced by roller electrospinning were greater than those produced by needle electrospinning. Moreover, increasing the concentration of the silk solution and the applied voltage in the spinning process improved the production rate in roller electrospinning but had less influence on the production rate in needle electrospinning.

  16. 刀辊和砧辊硬度匹配试验研究%Study on hardness matching of knife roller and anvil roller

    Institute of Scientific and Technical Information of China (English)

    廖昌城

    2015-01-01

    提高刀辊材料硬度可减少磨损,延长其使用寿命,提高模切速度,但会导致与之配合的砧辊损伤更为严重。为了使刀辊和砧辊系统总磨损量达到最小,试验研究了刀辊和砧辊的硬度匹配问题。利用滚动磨损试验机研究了刀辊与砧辊的硬度匹配,分析了不同硬度刀辊与砧辊匹配时的摩擦磨损与表面损伤行为。结果表明:不同硬度刀辊和砧辊试样匹配对滚动摩擦系数基本无影响;随刀辊硬度增加,刀辊磨损量呈下降趋势,砧辊磨损量表现为线性增加,刀辊和砧辊总磨损量呈先降低后增加的趋势,当刀辊与砧辊硬度比为1.016时,刀辊和砧辊系统总磨损量达到最小。刀辊硬度对刀辊和砧辊试样表面损伤形貌没有影响,刀辊和砧辊试样表面损伤形貌均表现为表面剥落损伤机制。%Increaing the hardness of knife roller material can reduce the knife roller’s wear,prolong its service life and improve its cutting speed,but it might result in more serious damage of the matched anvil roller.To minimize the overall wear of the knife roller and the anvil roller,the hard-ness matching of the knife roller and the anvil roller was researched via rolling wear testing machine. The friction wear and surface damage behaviours of the knife roller and the anvil roller samples matched under different hardnesses were analysed.The matching of the knife roller and anvil roller samples under different hardness had no effect on rolling friction coefficient.The knife roller’s wear decreased with the increase of the roller’s hardness while the wear of the anvil roller increased line-arly.The overall wear of the knife roller and the anvil roller samples decreased but then increased. When the hardness ratio of the knife roller to the anvil roller is 1.016,the overall system wear of the knife roller and the anvil roller minimized.The knife roller’s hardness had no effect on the

  17. Rotor-Bearing Dynamics Technology Design Guide. Part 4. Cylindrical Roller Bearings

    Science.gov (United States)

    1979-12-01

    ýbluck ,,lb.,mb i Tapered Roller Bearings Roller Beating Stiffness Tapered Roller Bearing Stiffness Turbine Bearings VRoller Bearings Rotordynamics ...input for rotordynamic response programs. The complete stiffness matrix is calculated including centrifugal effects. Considerations such as elastohydro...those parts directly connected with preparation of input for the rotordynamic response programs (Part 1(5) of the revised series) were retained. The

  18. Analysis of the quality renovated continuous steel casting roller

    Indian Academy of Sciences (India)

    J Viňáš; J Brezinová; A Guzanová

    2013-06-01

    This paper presents the possibility of restoration of worn contact surfaces of rollers for continuous casting of steel. Permanent effort of steel producers to extend the lifespan of these components requires the implementation of new filler materials or modifying technological renovation processes to reduce the economic costs. This matter seems to be very important for the world leaders in steel production, e.g., ArcelorMittal, Tata Steel, but also for smaller concerns such as Magnitogorsk Iron and Steel Works, Salzgitter, etc. Renovation of continuous steel casting rollers, made of X12Cr13 EN 10088-1-97, was realised using submerged arc surfacing technology. Worn surface of roller was machined and surfaced using one interlayer and two cover layers. The quality of deposited layers was verified using non-destructive and destructive tests. The influence of filler material on the tribological properties of contact surfaces of deposited layers was analysed by abrasive wear test. Studies were made in the influence of surfacing parameters on cladding metal mixing (mixed) with base metal and also influence of heat introduced by welding using metallographic analysis. The experiments confirmed very good wear resistance of the applied filler metal due to dispersion strengthening caused by finely dispersed carbides and nitrides in the weld coating. The measures to be taken into account in renovation of rollers using hard surfacing, as well as the development of research in this area were also given. The experiments have confirmed that parameters used are suitable for studying filler materials.

  19. The Process Analysis of the Roller Stretching for Wool Slenderization

    Institute of Scientific and Technical Information of China (English)

    刘洪玲; 于伟东; 章悦庭

    2003-01-01

    A theoretical estimation for the multiple-drawing has been derived under the consideration of fiber length distribution for the wool fiber stretching system. The functions of the roller drawing system and the parameters in stretching process have also been analyzed. The theoretical algorithms have been verified by the experimental results and can be used for the estimation of fiber length and its distribution after the stretching.

  20. Kinematics and Path Following Control of an Articulated Drum Roller

    Science.gov (United States)

    BIAN, Yongming; YANG, Meng; FANG, Xiaojun; WANG, Xiahui

    2017-07-01

    Automatic navigation of an articulated drum roller, which is an articulated steering type vehicle widely used in the construction industry, is highly expected for operation cost reduction and improvement of work efficiency. In order to achieve the path following control, considering that its steering system is articulated steering and two frames are articulated by an active revolute joint, a kinematic model and an error dynamic state-space equation of an articulated drum roller are proposed. Besides, a state-feedback control law based on Lyapunov stability theory is also designed, which can be proved to achieve the purpose of control by the analysis of stability. What's more, to evaluate the performance of the proposed method, simulation under the MATLAB/Simulink and experiments using positioning algorithm and errors correction at the uneven construction site are performed, with initial displacement error (-1.5 m), heading error (-0.11 rad) and steering angle (-0.19 rad). Finally, simulation and experimental results show that the errors and steering angle can decrease gradually, and converge to zero with time. Meanwhile, the control input is not saturated. An articulated drum roller can lock into a desired path with the proposed method in uneven fields.

  1. Development of A Revolving Die and Roller Fish Feed Pelletizer

    Directory of Open Access Journals (Sweden)

    Theresa K. Kaankuka

    2013-02-01

    Full Text Available A revolving die and roller type pelletizing machine was designed and constructed to produce fish feed pellets for small scale fish farmers. The major components of the pelletizer were the hopper, rollers, a flat die, shaft, discharge tray, frame, V-belt, V-pulley and electric motor. These components were designed based on strength and rigidity. An electric motor drives the die by a shaft connected to its pulley. The rotation of the die initiates the rotation of the rollers which pick up the feed material and compress it into the die holes to form pellets. The pelletizing machine was tested at two speed levels of 507 and 761 rpm and at three moisture content (MC levels (wet basis of 20, 25 and 30�20At 30�0MC, highest pellet output of 34.3 kg/hr and 40.4 kg/hr were obtained for die speeds of 507 and 761 rpm respectively. Higher pellet output obtained from die speed of 761 rpm could be as a result of the production of higher heat which resulted in proper gelatinization of the carbohydrate in the compounded feed. The gelatinized starch acts as a binding agent and this reduces crumbling during pelleting. The small and medium scale fish farmer can operate the machine because of its simplicity and this will alleviate the problem of sourcing for imported fish feed.

  2. SKF TOROIDAL ROLLER BEARING CARB – PRODUCTIVITY IMPROVEMENT AND MAINTENANCE COST REDUCTION THROUGH RELIABILITY AND SUSTAINABILITY

    Directory of Open Access Journals (Sweden)

    Tiberiu LAURIAN

    2010-06-01

    Full Text Available The CARB bearing is a single row bearing with long, slightly crowned symmetrical rollers. It combines the self-aligning capability of the spherical roller bearing with the unconstrained axial displacement ability of the cylindrical roller bearing. The optimal combination of both raceway profiles provides a favorable load distribution in the bearing, as well as low frictional running. This paper emphasizes the functioning characteristics of the SKF CARB toroidal roller bearing by means of a multibody dynamics simulation. Different conditions like load direction, races relative position or angular misalignment, are taken into consideration.

  3. Identification of loading conditions resulting in roller slippage in gearbox bearings of large wind turbines

    DEFF Research Database (Denmark)

    Dabrowski, Dariusz; Natarajan, Anand

    2017-01-01

    The dynamic loads on the rollers inside the bearings of large wind turbine gearboxes operating under transient conditions are presented with a focus on identifying conditions leading to slippage of rollers. The methodology was developed using a multi-body model of the drivetrain coupled with aero......The dynamic loads on the rollers inside the bearings of large wind turbine gearboxes operating under transient conditions are presented with a focus on identifying conditions leading to slippage of rollers. The methodology was developed using a multi-body model of the drivetrain coupled...

  4. The dynamics and optimal control of spinning spacecraft and movable telescoping appendages, part A. [two axis control with single offset boom

    Science.gov (United States)

    Bainum, P. M.; Sellappan, R.

    1977-01-01

    The problem of optimal control with a minimum time criterion as applied to a single boom system for achieving two axis control is discussed. The special case where the initial conditions are such that the system can be driven to the equilibrium state with only a single switching maneuver in the bang-bang optimal sequence is analyzed. The system responses are presented. Application of the linear regulator problem for the optimal control of the telescoping system is extended to consider the effects of measurement and plant noises. The noise uncertainties are included with an application of the estimator - Kalman filter problem. Different schemes for measuring the components of the angular velocity are considered. Analytical results are obtained for special cases, and numerical results are presented for the general case.

  5. Roller compaction: Effect of relative humidity of lactose powder.

    Science.gov (United States)

    Omar, Chalak S; Dhenge, Ranjit M; Palzer, Stefan; Hounslow, Michael J; Salman, Agba D

    2016-09-01

    The effect of storage at different relative humidity conditions, for various types of lactose, on roller compaction behaviour was investigated. Three types of lactose were used in this study: anhydrous lactose (SuperTab21AN), spray dried lactose (SuperTab11SD) and α-lactose monohydrate 200M. These powders differ in their amorphous contents, due to different manufacturing processes. The powders were stored in a climatic chamber at different relative humidity values ranging from 10% to 80% RH. It was found that the roller compaction behaviour and ribbon properties were different for powders conditioned to different relative humidities. The amount of fines produced, which is undesirable in roller compaction, was found to be different at different relative humidity. The minimum amount of fines produced was found to be for powders conditioned at 20-40% RH. The maximum amount of fines was produced for powders conditioned at 80% RH. This was attributed to the decrease in powder flowability, as indicated by the flow function coefficient ffc and the angle of repose. Particle Image Velocimetry (PIV) was also applied to determine the velocity of primary particles during ribbon production, and it was found that the velocity of the powder during the roller compaction decreased with powders stored at high RH. This resulted in less powder being present in the compaction zone at the edges of the rollers, which resulted in ribbons with a smaller overall width. The relative humidity for the storage of powders has shown to have minimal effect on the ribbon tensile strength at low RH conditions (10-20%). The lowest tensile strength of ribbons produced from lactose 200M and SD was for powders conditioned at 80% RH, whereas, ribbons produced from lactose 21AN at the same condition of 80% RH showed the highest tensile strength. The storage RH range 20-40% was found to be an optimum condition for roll compacting three lactose powders, as it resulted in a minimum amount of fines in the

  6. New Low Cost Structure for Dual Axis Mount Solar Tracking System Using Adaptive Solar Sensor

    DEFF Research Database (Denmark)

    Argeseanu, Alin; Ritchie, Ewen; Leban, Krisztina Monika

    2010-01-01

    A solar tracking system is designed to optimize the operation of solar energy receivers. The objective of this paper is proposing a new tracking system structure with two axis. The success strategy of this new project focuses on the economical analysis of solar energy. Therefore it is important...... to determine the most cost effective design, to consider the costs of production and maintenance, and operating. The proposed tracking system uses a new solar sensor position with an adaptive feature....

  7. Textile processing improvements due to high speed roller ginning of upland cotton

    Science.gov (United States)

    Selective breeding has improved upland cotton fiber properties. Processing capacities of new high-speed roller ginning technology approach that of saw ginning. Spinning mills are interested in mill performance data comparing new upland cultivars processed by both saw and roller ginning. Four dive...

  8. Aspects of geometric calculation of the planetary gear train with intermediate rollers. Part 1

    Science.gov (United States)

    I-Kan, An; Il'In, A. S.; Lazurkevich, A. V.

    2016-04-01

    The paper presents the geometric calculation of the planetary gear train with intermediate rollers, where the number of intermediate rollers is greater or less than that of the teeth in the annular gear by one, the profile surface of the annular gear teeth being the same. The gear ratio is changed by both a value and a sign.

  9. Aspects of geometric calculation of the planetary gear train with intermediate rollers. Part 1

    OpenAIRE

    An I-Kan; Ilin, A. S.; Lazurkevich, A. V.

    2016-01-01

    The paper presents the geometric calculation of the planetary gear train with intermediate rollers, where the number of intermediate rollers is greater or less than that of the teeth in the annular gear by one, the profile surface of the annular gear teeth being the same. The gear ratio is changed by both a value and a sign.

  10. INFLUENCE CONSTRUCTION OF THE ROLLER ON THE POWER OF THE DRIVE SYSTEM OF THE BELT CONVEYOR

    Directory of Open Access Journals (Sweden)

    Tadeusz OPASIAK

    2014-09-01

    Full Text Available The paper presents a study of new design of rollers. The study focused on the measurement of static and dynamic resistance of rotating rollers and the impact of new construction on the power consumption of the belt conveyor. Rollers have been modified through the use of class C4 bearing seals and labyrinth seal U4Exp 62/65 with a cover 2LU4 of runner construction. Measurements of static and dynamic resistance of rotating rollers were made on a universal rollers stand and power measurements were carried out on a belt conveyor power supply system Gwarek 1200 No. TW in mine KWK Mysłowice–Wesoła.

  11. Experimental performance investigation of glazing system combined with internal roller blinds

    DEFF Research Database (Denmark)

    Larsen, Olena Kalyanova; Jensen, Rasmus Lund; Iversen, Tore Dahl;

    2016-01-01

    is carried out by experimental work in a full-scale test facility, the Cube, with two types of window (double and triple glazed) and two types of solar shading: highly reflective roller blind and highly absorbing roller blind. Danish Building simulation software, BSim is used to illustrate the scale......-value of the system (window + roller blind). Solar shading coefficient in such practice is assumed to be independent of the window properties and solar incidence angle. This paper is aimed to illustrate the deviation between the actual and assumed performance of the window system with internal roller blind. This task...... of deviation between the experimental results and the results obtained with common assumptions for solar properties of shading device. It is concluded that the solar shading coefficient for an internal roller blind, as a standalone parameter, is not good enough to describe the solar properties of the system...

  12. A roller chain drive model including contact with guide-bars

    DEFF Research Database (Denmark)

    Pedersen, Sine Leergaard; Hansen, John Michael; Ambrósio, J. A. C.

    2004-01-01

    and continuous force methods, respectively. In the unilateral constraint methodology the kinematic constraints are introduced in the system anytime a contact between the rollers and the sprockets is detected. The condition for the constraint addition is based on the relative distance between the roller centre...... and the sprocket centre, i.e. a constraint is added when such distance is less than the pitch radius. The unilateral kinematic constraint is removed when its associated constraint reaction force, applied on the roller, is in the direction of the root of the sprocket teeth. In order to improve the numerical...... as continuous force. The model of the roller-chain drive now proposed departs from an earlier model where two contact/impact methods are proposed to describe the contact between the rollers of the chain and the teeth of the sprockets. These different formulations are based on unilateral constraints...

  13. FAULT DIAGNOSIS APPROACH FOR ROLLER BEARINGS BASED ON EMPIRICAL MODE DECOMPOSITION METHOD AND HILBERT TRANSFORM

    Institute of Scientific and Technical Information of China (English)

    Yu Dejie; Cheng Junsheng; Yang Yu

    2005-01-01

    Based upon empirical mode decomposition (EMD) method and Hilbert spectrum, a method for fault diagnosis of roller bearing is proposed. The orthogonal wavelet bases are used to translate vibration signals of a roller bearing into time-scale representation, then, an envelope signal can be obtained by envelope spectrum analysis of wavelet coefficients of high scales. By applying EMD method and Hilbert transform to the envelope signal, we can get the local Hilbert marginal spectrum from which the faults in a roller bearing can be diagnosed and fault patterns can be identified. Practical vibration signals measured from roller bearings with out-race faults or inner-race faults are analyzed by the proposed method. The results show that the proposed method is superior to the traditional envelope spectrum method in extracting the fault characteristics of roller bearings.

  14. Simulation modeling of wheeled vehicle dynamics on the stand "Roller"

    Directory of Open Access Journals (Sweden)

    G. O. Kotiev

    2014-01-01

    Full Text Available The tests are an integral part of the wheeled vehicle design, manufacturing, and operation. The need for their conducting arises from the research and experimental activities to assess the qualitative and quantitative characteristics of the vehicles in general, as well as the individual components and assemblies. It is obvious that a variety of design features of wheeled vehicles request a development of methods both for experimental studies and for creating the original bench equipment for these purposes.The main positive feature of bench tests of automotive engineering is a broad capability to control the combinations of traction loads, speed rates, and external input conditions. Here, the steady state conditions can be used for a long time, allowing all the necessary measurements to be made, including those with video and photo recording experiment.It is known that the benefits of test "M" type (using a roller dynamometer include a wide range of test modes, which do not depend on the climatic conditions, as well as a capability to use a computer-aided testing programs. At the same time, it is known that the main drawback of bench tests of full-size vehicle is that the tire rolling conditions on the drum mismatch to the real road pavements, which are difficult to simulate on the drum surface. This problem can be solved owing to wheeled vehicle tests at the benches "Roller" to be, in efficiency, the most preferable research method. The article gives a detailed presentation of developed at BMSTU approach to its solving.Problem of simulation mathematical modeling has been solved for the vehicle with the wheel formula 8 × 8, and individual wheel-drive.The simulation results have led to the conclusion that the proposed principle to simulate a vehicle rolling on a smooth non-deformable support base using a bench " Roller " by simulation modeling is efficient.

  15. Positron annihilation lifetime spectroscopy study of roller burnished magnesium alloy

    Directory of Open Access Journals (Sweden)

    Zaleski Radosław

    2015-12-01

    Full Text Available The effect of roller burnishing on Vickers’ hardness and positron lifetimes in the AZ91HP magnesium alloy was studied. The microhardness increases with an increase in the burnishing force and with a decrease in the feed. The comparison of various methods of analysis of positron annihilation lifetime (PAL spectra allowed identification of two components, which are related to solute-vacancy complexes and vacancy clusters, respectively. It was found that the increase in microhardness was related to the increase in the concentration of vacancy clusters.

  16. Hot Roller Embossing for the Creation of Microfluidic Devices

    CERN Document Server

    Ng, Sum Huan

    2008-01-01

    We report on the hot roller embossing of polymer sheets for the creation of microfluidic structures. Measurements conducted on 100 $\\mu$m features showed that the lateral dimensions could be replicated to within 2% tolerance, while over 85% of mould depth was embossed. Feature sizes down to 50 $\\mu$m and feature depths up to 30 $\\mu$m had been achieved. At lower temperatures, asymmetric pile up of polymer material outside embossed regions was observed with higher pile up occurring on the trailing side of the embossed regions.

  17. Foam roller kestävyysjuoksijan iliotibiaalisen hankaussyndrooman fysioterapiassa

    OpenAIRE

    Eskelinen, Anne

    2014-01-01

    Opinnäytetyön tavoitteena oli selvittää, onko foam rollerin käytöstä hyötyä kestävyysjuoksijan iliotibiaalisen hankaussyndrooman (ITBFS) fysioterapiassa. Työ koostuu kirjallisuuskatsauksesta ja fysioterapeuttien henkilökohtaisista tiedonannoista. Foam roller on fysioterapiassa useiden vuosikymmenten ajan käytetty terapiaväline, jonka käyttö on yleistynyt urheilijoiden keskuudessa 2010-luvulla. ITBFS on kestävyysjuoksijoille tyypillinen rasitusvamma, jonka oireet ilmenevät polven ja ulkore...

  18. Fuzzy fault tree analysis of roller oscillating tooth gear drive

    Institute of Scientific and Technical Information of China (English)

    李瑰贤; 杨伟君; 张欣; 李笑; 刘福利

    2002-01-01

    Conventional fault tree and reliability analysis do not reflect the characteristics of basic events asnon-stationary and ergodic process. To overcome these drawbacks, theory of fuzzy sets is employed to run faulttree analysis(FTA) of roller oscillating tooth gear drive( ROTGD), the relative frequencies of basic events areconsidered as symmetrical normal fuzzy numbers, from the logical relationship between different events in thefault tree and fuzzy operators AND and OR, fuzzy probability of top event is solved. Finally, an example is giv-en to demonstrate a real ROTGD system.

  19. Roller Bearing Monitoring by New Subspace-Based Damage Indicator

    Directory of Open Access Journals (Sweden)

    G. Gautier

    2015-01-01

    Full Text Available A frequency-band subspace-based damage identification method for fault diagnosis in roller bearings is presented. Subspace-based damage indicators are obtained by filtering the vibration data in the frequency range where damage is likely to occur, that is, around the bearing characteristic frequencies. The proposed method is validated by considering simulated data of a damaged bearing. Also, an experimental case is considered which focuses on collecting the vibration data issued from a run-to-failure test. It is shown that the proposed method can detect bearing defects and, as such, it appears to be an efficient tool for diagnosis purpose.

  20. A composite control method based on the adaptive RBFNN feedback control and the ESO for two-axis inertially stabilized platforms.

    Science.gov (United States)

    Lei, Xusheng; Zou, Ying; Dong, Fei

    2015-11-01

    Due to the nonlinearity and time variation of a two-axis inertially stabilized platform (ISP) system, the conventional feedback control cannot be utilized directly. To realize the control performance with fast dynamic response and high stabilization precision, the dynamic model of the ISP system is expected to match the ideal model which satisfies the desired control performance. Therefore, a composite control method based on the adaptive radial basis function neural network (RBFNN) feedback control and the extended state observer (ESO), is proposed for ISP. The adaptive RBFNN is proposed to generate the feedback control parameters online. Based on the state error information in the working process, the adaptive RBFNN can be constructed and optimized directly. Therefore, no priori training data is needed for the construction of the RBFNN. Furthermore, a linear second-order ESO is constructed to compensate for the composite disturbance. The asymptotic stability of the proposed control method has been proven by the Lyapunov stability theory. The applicability of the proposed method is validated by a series of simulations and flight tests.

  1. Erythrocyte Fragment Count Predicts Hemolysis in Roller Pumps

    Institute of Scientific and Technical Information of China (English)

    FAN Jun-qiang; XU Shi-wei; CHEN Fang; DING Min-jun

    2007-01-01

    Hemolysis in blood pumps has been measured by various in vitro test methods, in which normalized index of hemolysis (NIH) was established. As NIH is complicated and difficult to calculate, erythrocyte fragment count is proposed in the present study to predict hemolysis in roller pumps. Methods: Five paired in vitro tests wereconducted using the POLYSTAN pediatric pump(group A) and COBE pump(group B). Ten whole blood samples (400 ml ) were circled in the roller pump for 16 h. Erythrocyte fragments count and plasma-free hemoglobin (FHb) were measured before pumping and every two hours through circulation after four-hour-pumping. The morphological changes of erythrocyte were observed by scanning electron microscope. Results: The two groups' EFC and FHb levels were increased linearly during a long duration of pumping and linear regression of erythrocyte fragments count and plasma-free hemoglobin were correlated. Conclusion: Erythrocyte fragments count could be used as an index in evaluating the in vitro hemolytic properties of blood pumps.

  2. Fast EEMD Based AM-Correntropy Matrix and Its Application on Roller Bearing Fault Diagnosis

    Directory of Open Access Journals (Sweden)

    Yunxiao Fu

    2016-06-01

    Full Text Available Roller bearing plays a significant role in industrial sectors. To improve the ability of roller bearing fault diagnosis under multi-rotating situation, this paper proposes a novel roller bearing fault characteristic: the Amplitude Modulation (AM based correntropy extracted from the Intrinsic Mode Functions (IMFs, which are decomposed by Fast Ensemble Empirical mode decomposition (FEEMD and employ Least Square Support Vector Machine (LSSVM to implement intelligent fault identification. Firstly, the roller bearing vibration acceleration signal is decomposed by FEEMD to extract IMFs. Secondly, IMF correntropy matrix (IMFCM as the fault feature matrix is calculated from the AM-correntropy model of the primary vibration signal and IMFs. Furthermore, depending on LSSVM, the fault identification results of the roller bearing are obtained. Through the bearing identification experiments in stationary rotating conditions, it was verified that IMFCM generates more stable and higher diagnosis accuracy than conventional fault features such as energy moment, fuzzy entropy, and spectral kurtosis. Additionally, it proves that IMFCM has more diagnosis robustness than conventional fault features under cross-mixed roller bearing operating conditions. The diagnosis accuracy was more than 84% for the cross-mixed operating condition, which is much higher than the traditional features. In conclusion, it was proven that FEEMD-IMFCM-LSSVM is a reliable technology for roller bearing fault diagnosis under the constant or multi-positioned operating conditions, and as such, it possesses potential prospects for a broad application of uses.

  3. Armed rollers: does nestling's vomit function as a defence against predators?

    Directory of Open Access Journals (Sweden)

    Deseada Parejo

    Full Text Available Chemical defences against predators are widespread in the animal kingdom although have been seldom reported in birds. Here, we investigate the possibility that the orange liquid that nestlings of an insectivorous bird, the Eurasian roller (Coracias garrulus, expel when scared at their nests acts as a chemical defence against predators. We studied the diet of nestling rollers and vomit origin, its chemical composition and deterrent effect on a mammal generalist predator. We also hypothesized that nestling rollers, as their main prey (i.e. grasshoppers do from plants, could sequester chemicals from their prey for their use. Grasshoppers, that also regurgitate when facing to a threat, store the harmful substances used by plants to defend themselves against herbivores. We found that nestling rollers only vomit after being grasped and moved. The production of vomit depended on food consumption and the vomit contained two deterrent chemicals (hydroxycinnamic and hydroxybenzoic acids stored by grasshoppers and used by plants to diminish herbivory, suggesting that they originate from the rollers' prey. Finally, we showed for the first time that the oral secretion of a vertebrate had a deterrent effect on a model predator because vomit of nestling rollers made meat distasteful to dogs. These results support the idea that the vomit of nestling rollers is a chemical defence against predators.

  4. Subdural hematoma in a teenager related to roller-coaster ride.

    Science.gov (United States)

    Roldan-Valadez, Ernesto; Facha, M T; Martinez-Lopez, Manuel; Herrera-Mora, Patricia

    2006-07-01

    Reports about neurological injury related to roller-coaster rides mostly involve adults; we present a case of subdural hematoma in a pediatric patient presented 14 days after a roller-coaster ride. These rides show extreme up-and-down, to-and-fro, and rotatory acceleration/deceleration forces that could produce tensile and shearing stresses with tearing of bridging cerebral veins resulting in subdural hemorrhage. Pediatricians should consider roller-coaster riding a modern cause of subdural hematoma, as well as a possible cause of unexplained neurologic events in otherwise healthy adolescents.

  5. Magnetic Launch Assist Experimental Track

    Science.gov (United States)

    1999-01-01

    In this photograph, a futuristic spacecraft model sits atop a carrier on the Magnetic Launch Assist System, formerly known as the Magnetic Levitation (MagLev) System, experimental track at the Marshall Space Flight Center (MSFC). Engineers at MSFC have developed and tested Magnetic Launch Assist technologies that would use magnetic fields to levitate and accelerate a vehicle along a track at very high speeds. Similar to high-speed trains and roller coasters that use high-strength magnets to lift and propel a vehicle a couple of inches above a guideway, a Magnetic Launch Assist system would electromagnetically drive a space vehicle along the track. A full-scale, operational track would be about 1.5-miles long and capable of accelerating a vehicle to 600 mph in 9.5 seconds. This track is an advanced linear induction motor. Induction motors are common in fans, power drills, and sewing machines. Instead of spinning in a circular motion to turn a shaft or gears, a linear induction motor produces thrust in a straight line. Mounted on concrete pedestals, the track is 100-feet long, about 2-feet wide, and about 1.5-feet high. The major advantages of launch assist for NASA launch vehicles is that it reduces the weight of the take-off, the landing gear, the wing size, and less propellant resulting in significant cost savings. The US Navy and the British MOD (Ministry of Defense) are planning to use magnetic launch assist for their next generation aircraft carriers as the aircraft launch system. The US Army is considering using this technology for launching target drones for anti-aircraft training.

  6. MECHANISM OF ORIGIN OF STRUCTURAL VIBRATIONS IN CONICAL ROLLER BEARINGS

    Directory of Open Access Journals (Sweden)

    V.І. Marchuk

    2014-09-01

    Full Text Available This paper investigates the mechanism of origin of structural, structural and technological defects of rollers. The technique for integrated indicator of vibration working surfaces of the rings to determine the level of life of the finished part to the operation as part of the bearing and predict the vibroacoustic characteristics of rolling bearings. It was established that technological defects cause low-frequency and high-frequency vibrations. The question about the extent to which it is necessary to strengthen the tolerances on the parameters of bearings on which vibration level is determined not errors bearing parts and their structural properties. Calculated values of the amplitudes vibroacceleration due to the rigidity of the bearing vibrations are so small that in some cases adopted precision calculations turned enough to detect such vibrations. Thus, when tested on the vibro-acoustic installations structural vibration does not play an important role.

  7. Computer-Aided Detection System on Tangled Roller

    Institute of Scientific and Technical Information of China (English)

    闫贺庆; 牛新文; 王成焘

    2004-01-01

    The mechanical-touched detector was used commonly in textile production limes. It has some defect with high false alarm rate, response delay and high maintenance cost. In order to overcome such defects, a new kind device was developed and used to detect roller tangled in the production lines. It is based on image processing. The core algorithm was composed of Canny edge detection, removing interference, detection of perpendicularity line and detection of broken tow. After the four steps, the broken tow could be recognized quickly and correctly. The algorithm is robust and high efficiency. So, the detection device has characteristic of stable, quickly-response and low maintains cost. It can keep superiority with long lifespan even in more formidable conditions. It guarantees a safe and stable production condition.

  8. Roller coaster marathon: being a live liver donor.

    Science.gov (United States)

    Cabello, Charlotte C; Smolowitz, Janice

    2008-09-01

    The purpose of this phenomenological study was to examine the meaning of being a live liver donor. Six people between ages 27 and 53 years participated. A qualitative, in-depth, semistructured interview format was used to explore donors' thoughts and feelings about being an organ donor. Five themes were identified: (1) no turning back--how do I live without you? (2) roller coaster marathon, (3) donor network, (4) the scar, and (5) reflections--time to think. At the center of the experience was the donor's commitment to the recipient. Once donors began the process, they were determined to see it through. The process was complex, and donors received various levels of support from family, friends, health care professionals, and others. After donation, as donors recovered and were able to resume their usual daily responsibilities, they reflected on the impact of the experience and how it changed their view of life.

  9. Grinding process within vertical roller mills: experiment and simulation

    Institute of Scientific and Technical Information of China (English)

    WANG Jian-huai; CHEN Qing-ru; KUANG Ya-li; LYNCH A J; ZHUO Jin-wu

    2009-01-01

    Based on screening analysis, laser size analysis, grindability and rigidity tests of samples collected on line from a cement and a power plant, a simulation of the grinding process in vertical roller mills was carried out. The simulation calculation used a breakage function, B. The results indicate that the breakage function, B, and the selection function, S, in the form of a matrix, can be used to express the probability of the material breaking during the grinding process. This allows the size distribution of the product to be numerically estimated. The simulation results also show that the simulated size distribution curves fit the actual ex-perimental product curves quite well. The model provides a good starting point for simulation of the grinding process. Further re-search is needed to determine the proper breakage function and the matrix value of the selection function.

  10. Roller Bearing Health Monitoring Using CPLE Frequency Analysis Method

    Science.gov (United States)

    Jong, Jen-Yi; Jones, Jess H.

    2007-01-01

    This paper describes a unique vibration signature analysis technique Coherence Phase Line Enhancer (CPLE) Frequency Analysis - for roller bearing health monitoring. Defects of roller bearing (e.g. wear, foreign debris, crack in bearing supporting structure, etc.) can cause small bearing characteristic frequency shifts due to minor changes in bearing geometry. Such frequency shifts are often too small to detect by the conventional Power Spectral Density (PSD) due to its frequency bandwidth limitation. This Coherent Phase Line Enhancer technology has been evolving over the last few years and has culminated in the introduction of a new and novel frequency spectrum which is fully described in this paper. This CPLE technology uses a "key phasor" or speed probe as a preprocessor for this analysis. With the aid of this key phasor, this CPLE technology can develop a two dimensional frequency spectrum that preserves both amplitude and phase that is not normally obtained using conventional frequency analysis. This two-dimensional frequency transformation results in several newly defined spectral functions; i. e. CPLE-PSD, CPLE-Coherence and the CPLE-Frequency. This paper uses this CPLE frequency analysis to detect subtle, low level bearing related signals in the High Pressure Fuel Pump (HPFP) of the Space Shuttle Main Engine (SSME). For many rotating machinery applications, a key phasor is an essential measurement that is used in the detection of bearing related signatures. There are times however, when a key phasor is not available; i. e. during flight of any of the SSME turbopumps or on the SSME High Pressure Oxygen Turbopump (HPOTP) where no speed probe is present. In this case, the CPLE analysis approach can still be achieved using a novel Pseudo Key Phasor (PKP) technique to reconstruct a 1/Rev PKP signal directly from external vibration measurements. This paper develops this Pseudo Key Phasor technique and applies it to the SSME vibration data.

  11. Temperature control of transfer roller's bearing based on finite element analysis

    Institute of Scientific and Technical Information of China (English)

    Peng ZHANG; Yourong LI; Han XIAO

    2009-01-01

    After a heat preservation cover is installed on the main rolling line, the heat dissipation environment of the transfer roller working on the heat preservation cover is changed. To ensure the normal production, a reasonable working jet capacity of the roller neck is derived. First, a globe model of the transfer roller is built for finite element analysis. Second, the sub-model of the fixed end bearing is built and the boundary condition of the sub-model is supplied by the results of the globe model. The analysis result of the sub-model shows that the temperature of the transfer roller bearing exceeds 85℃ a rolling periodicity later. With finite element analysis, the heat flux is obtained and the minimum working jet capacity is derived.

  12. Analysis of bearings behaviour with cylindrical rollers with variable center of gravity

    Directory of Open Access Journals (Sweden)

    Barabas Sorin

    2017-01-01

    Full Text Available This paper consists in analysis of the contact stress and deformations appeared to the cylindrical rollers with variable center of gravity who equips large bearings, with finite elements method. Also it proposed an innovative model of lubrication system mounts in the hollow cylindrical rollers of the large bearings where it is stored the lubricant who is driven to the raceways through holes fitted with closing/opening systems made in the cover, controlled by a command system, monitoring and control, equipped with temperature sensors and wireless command. Elimination of lubricant, in stages, leads to changes in position of center of gravity of roller, thus to change its behavior in functioning. Comparison of deformations occurred in cylindrical rollers, solid, with hollowness, and with variable center of gravity, allow favorable conclusions, on the implementation of the proposed lubrication system.

  13. CHINESE JOURNAL OF MECHANICAL ENGINEERING RELIABILITY AND OPTIMIZATION DESIGN OF NEW ROLLER ORIENTATION CLUTCH

    Institute of Scientific and Technical Information of China (English)

    2002-01-01

    The mechanical reliability and optimization theory on the method of reliability-optimization design for the new roller orientation clutch is provided. The result of reliability-optimization design is compared with the result of the conventional design method.

  14. KINEMATICS AND DYNAMICS MODELS OF CYLINDRICAL ROLLER BEARING OF RAILWAY TRANSPORT

    Directory of Open Access Journals (Sweden)

    A. V. Gaydamaka

    2014-05-01

    Full Text Available Purpose. Lack of kinematics models and imperfection of the known dynamics models of the roller bearings of railway rolling stock axle-boxes do not allow designing the optimal structure of bearing cages, providing the required service life and reliability of bearing units of wheel sets for cars and locomotives. The studies of kinematics and dynamics of roller bearings of axle boxes for cars and locomotives and modeling of their parts interaction to create the analytical method of bearing cages calculation are necessary. Methodology. This purpose has been achieved due to the modeling of kinematics of the ideal (without gaps and real (taking account the gaps, manufacturing and installation errors bearings, substantiation of the transfer mechanism of motion from the rollers to bearing cage, modeling the dynamics of rolling, research of interaction forces of the rollers with bearing cage. Findings. It is established that the kinematics of ideal bearing is determined by the contact deformations of the rollers and rings, when the kinematics of real bearing depends mainly on the side gaps in the windows of the bearing cage. On the basis of studies of the real bearing kinematics the dynamics models of the rollers and bearing cage interaction were constructed. The conducted studies of kinematics and dynamics of rolling bearings have changed our view of them as of the planetary mechanism, explained the reason of bearing cage loading, and confirmed the possibility of destruction during operation. Originality. It was first proposed a mechanism for motion transfer from the rollers to the bearing cage of roller bearings, consisting in that the side gap in the bearing cage window is reduced gradually multiple of the number of rollers of radial loading area according to the bearing cage motion. The models of roller bearing dynamics, which allow calculating the interaction forces of parts for all modes of operation, were improved. Practical value. Use of the

  15. 对辊破碎机高锰钢辊轮加工工艺分析%Machining Process Analysis for High Manganese Steel Roller of Roller Crusher

    Institute of Scientific and Technical Information of China (English)

    张磊; 崔守彬; 李宏士

    2013-01-01

    According to the introduction of using requirement for roller crusher structure and high manga -nese steel roller , analyze the feasibility of roller material performance and machining and present the machining process plan for it .Through the application during the production , the feasibility of this plan is tested and verified .%通过对对辊破碎机的结构及其高锰钢辊轮使用要求的介绍,对辊轮的材料性能要求和加工可行性进行了分析,提出了加工工艺方案。通过生产过程中的应用,方案得到了可行性验证。

  16. Pilot Findings of Brain Displacements and Deformations during Roller Coaster Rides.

    Science.gov (United States)

    Kuo, Calvin; Wu, Lyndia C; Ye, Patrick P; Laksari, Kaveh; Camarillo, David B; Kuhl, Ellen

    2017-08-14

    With 300,000,000 riders annually, roller coasters are a popular recreational activity. Although the number of roller coaster injuries is relatively low, the precise effect of roller coaster rides on our brains remains unknown. Here we present the quantitative characterization of brain displacements and deformations during roller coaster rides. For two healthy adult male subjects, we recorded head accelerations during three representative rides, and, for comparison, during running and soccer headers. From the recordings, we simulated brain displacements and deformations using rigid body dynamics and finite element analyses. Our findings show that despite having lower linear accelerations than sports head impacts, roller coasters may lead to brain displacements and strains comparable to mild soccer headers. The peak change in angular velocity on the rides was 9.9 rad/sec, which was higher than the 5.6 rad/sec in soccer headers with ball velocities reaching 7 m/sec. Maximum brain surface displacements of 4.0 mm and maximum principal strains of 7.6% were higher than in running and similar to soccer headers, but below the reported average concussion strain. Brain strain rates during roller coaster rides were similar to those in running, and lower than those in soccer headers. Strikingly, on the same ride and at a similar position, the two subjects experienced significantly different head kinematics and brain deformation. These results indicate that head motion and brain deformation during roller coaster rides are highly sensitive to individual subjects. Although our study suggests that roller coaster rides do not present an immediate risk of acute brain injury, their long-term effects require further longitudinal study.

  17. Bilateral vertebral artery dissection possibly precipitated in delayed fashion as a result of roller coaster rides.

    Science.gov (United States)

    Schneck, Michael; Simionescu, Monica; Bijari, Armita

    2008-01-01

    A 34-year-old woman presented with a 5-month history of persistent vertigo after multiple roller coaster rides, followed by neck pain for 1 month and then 2 weeks of blurred vision related to diplopia. She was ultimately found to have bilateral cervical vertebral artery dissection. The images are described and the literature is reviewed regarding late diagnosis of vertebral dissection and prior cases of roller coaster-associated dissection.

  18. Acute effects of self-myofascial release using a foam roller on arterial function.

    Science.gov (United States)

    Okamoto, Takanobu; Masuhara, Mitsuhiko; Ikuta, Komei

    2014-01-01

    Flexibility is associated with arterial distensibility. Many individuals involved in sport, exercise, and/or fitness perform self-myofascial release (SMR) using a foam roller, which restores muscles, tendons, ligaments, fascia, and/or soft-tissue extensibility. However, the effect of SMR on arterial stiffness and vascular endothelial function using a foam roller is unknown. This study investigates the acute effect of SMR using a foam roller on arterial stiffness and vascular endothelial function. Ten healthy young adults performed SMR and control (CON) trials on separate days in a randomized controlled crossover fashion. Brachial-ankle pulse wave velocity (baPWV), blood pressure, heart rate, and plasma nitric oxide (NO) concentration were measured before and 30 minutes after both SMR and CON trials. The participants performed SMR of the adductor, hamstrings, quadriceps, iliotibial band, and trapezius. Pressure was self-adjusted during myofascial release by applying body weight to the roller and using the hands and feet to offset weight as required. The roller was placed under the target tissue area, and the body was moved back and forth across the roller. In the CON trial, SMR was not performed. The baPWV significantly decreased (from 1,202 ± 105 to 1,074 ± 110 cm·s-1) and the plasma NO concentration significantly increased (from 20.4 ± 6.9 to 34.4 ± 17.2 μmol·L-1) after SMR using a foam roller (both p < 0.05), but neither significantly differed after CON trials. These results indicate that SMR using a foam roller reduces arterial stiffness and improves vascular endothelial function.

  19. Continuous overturn control of compactors/rollers by rollover protective structures

    Science.gov (United States)

    Myers, Melvin L.

    2009-01-01

    The objective of this article is to report on the effectiveness of Rollover Protective Structures (ROPS) in preventing continuous overturns of compactors/rollers. This study is a case-based analysis of government investigation reports of injury-related overturns of compactors/rollers. The overturns were predominately on construction sites including road and embankment construction in the USA. Other sites included driveway and roadway maintenance or repair and transporting of compactors/rollers either by driving or when loading on or unloading from trailers. The principle intervention observed in controlling a continuous overturn (a roll beyond 90° relative to the impact surface) was the presence of a ROPS on a compactor/roller that serves as an anti-roll bar. The main outcome measures are cases of compactor/roller overturns that are restricted to a 90° roll or are continuous (exceed a 90° roll.) All cases of an overturn in which a ROPS was present resulted in no continuous overturn, and the cases involved with no ROPS averaged an overturn of 301°, showing a propensity for a continuous overturn. This case-based analysis identified a ROPS on compactors/rollers as an effective control for reducing the risk of an overturn to 90° relative to the impact plane. PMID:21765649

  20. Impact Analysis of Roller System Stability for Four-High Mill Horizontal Vibration

    Directory of Open Access Journals (Sweden)

    Xiao-bin Fan

    2016-01-01

    Full Text Available In order to study the hot Compact Strip Production (CSP, four-high mill vibration characteristics, and vibration suppression method, the roller system structure stability was analyzed and calculated at first in the paper. And then, the mill stand gap was measured at field and its influence on roll transverse vibration was analyzed. The drum gear coupling effect on the roller system stability and the automatic balance conditions of the coupling transmission torque were studied; the influence of axial force caused by the roller cross on the system stability was analyzed. Finally, the roller transverse friction chatter vibration mechanics model was established; the simulation analysis was carried out with eliminating mill house-bearing clearance and adding floating support for coupling, respectively. And the characteristics of the roller “jump vibration” were studied. We applied copper gaskets to eliminate or reduce mill house-bearing clearance for suppressing the rolling mill vibration on the spot; the test results show that the roller transverse vibration was suppressed after eliminating clearance.

  1. Experimental Validation of a Compound Control Scheme for a Two-Axis Inertially Stabilized Platform with Multi-Sensors in an Unmanned Helicopter-Based Airborne Power Line Inspection System

    OpenAIRE

    2016-01-01

    A compound control scheme is proposed to achieve high control performance for a two-axis inertially stabilized platform (ISP) with multi-sensors applied to an unmanned helicopter (UH)-based airborne power line inspection (APLI) system. Compared with the traditional two closed-loop control scheme that is composed of a high-bandwidth rate loop and a lower bandwidth position loop, a new current loop inside rate loop is particularly designed to suppress the influences of voltage fluctuation from ...

  2. Back analysis of mechanical parameters of roller compacted concrete dam

    Institute of Scientific and Technical Information of China (English)

    2010-01-01

    In view of the diversity and complexity of mechanical parameters of roller compacted concrete dam(RCCD),the uniform design method,partial least-squares regression(PLS)and least squares support vector machine(LSSVM)were applied to the back analysis of RCCD with the use of the complex nonlinear relationship between dam mechanical parameters and dam displacements.During the process of back analysis,the initial samples of parameters were designed with uniform design method.Then,a transversely isotropic model of RCCD was established by MSC.Marc software.Through this model,training samples of LSSVM model could be obtained.And then,the complex nonlinear relationship between relative values of hydraulic components of dam displacements and mechanical parameters was established.Finally,actual relative values of dam hydraulic components are isolated from the measured data of dam displacements by using PLS.By inputting the isolated relative values into LSSVM model,the back analysis values of RCCD mechanical parameters can be obtained.The example analysis showed that mechanical parameters obtained by the above-mentioned back analysis method are reasonable,and the back analysis method is feasible.

  3. Analysis of laboratory compaction methods of roller compacted concrete

    Science.gov (United States)

    Trtík, Tomáš; Chylík, Roman; Bílý, Petr; Fládr, Josef

    2017-09-01

    Roller-Compacted Concrete (RCC) is an ordinary concrete poured and compacted with machines typically used for laying of asphalt road layers. One of the problems connected with this technology is preparation of representative samples in the laboratory. The aim of this work was to analyse two methods of preparation of RCC laboratory samples with bulk density as the comparative parameter. The first method used dynamic compaction by pneumatic hammer. The second method of compaction had a static character. The specimens were loaded by precisely defined force in laboratory loading machine to create the same conditions as during static rolling (in the Czech Republic, only static rolling is commonly used). Bulk densities obtained by the two compaction methods were compared with core drills extracted from real RCC structure. The results have shown that the samples produced by pneumatic hammer tend to overestimate the bulk density of the material. For both compaction methods, immediate bearing index test was performed to verify the quality of compaction. A fundamental difference between static and dynamic compaction was identified. In static compaction, initial resistance to penetration of the mandrel was higher, after exceeding certain limit the resistance was constant. This means that the samples were well compacted just on the surface. Specimens made by pneumatic hammer actively resisted throughout the test, the whole volume was uniformly compacted.

  4. Improving the granule strength of roller-compacted ibuprofen sodium for hot-melt coating processing.

    Science.gov (United States)

    Lopes, Diogo Gomes; Garsuch, Verena; Becker, Karin; Paudel, Amrit; Stehr, Michael; Zimmer, Andreas; Salar-Behzadi, Sharareh

    2016-08-20

    Solvent-free hot-melt coating processing is a novel and cost-efficient approach to manufacturing taste-masked multiparticulate systems. However, most API powders are fine and cohesive and not processable by hot-melt coating. The aim of this study was to produce dense and abrasion-resistant granules with high drug content (>80%) via roller compaction for hot-melt coating process optimization. The selected API was ibuprofen sodium dihydrate, a salt of ibuprofen with improved bioavailability and poor intrinsic compactibility. The formulation and roller compaction process were developed for the production of granules with 94%w/w of API and low friability (∼30%), using sorbitol and isomalt as excipients. The strong bonding mechanism relied on powder jamming prior to the rollers and was investigated via scanning electron microscopy, differential scanning calorimetry and small and wide angle X-ray scattering. It was shown that sorbitol crystals are solubilized during roller compaction and recrystallize as sorbitol hydrate, acting as strong solid bridges. The robustness of the roller compaction process and the re-compaction of fines were investigated. A statistical design of experiments was conducted to evaluate the hot-melt coating process for taste masking of ibuprofen sodium granules. Taste masking required coating ratios higher than 40%w/w of granule batch, emphasizing the need for high-drug-content and abrasion-resistant granules.

  5. Edgewise vibration control of wind turbine blades using roller and liquid dampers

    Science.gov (United States)

    Zhang, Z. L.; Nielsen, S. R. K.

    2014-06-01

    This paper deals with the passive vibration control of edgewise vibrations by means of roller dampers and tuned liquid column dampers (TLCDs). For a rotating blade, the large centrifugal acceleration makes it possible to use roller dampers or TLCDs with rather small masses for effectively suppressing edgewise vibrations. The roller dampers are more volumetrically efficient due to the higher mass density of the steel comparing with the liquid. On the other hand, TLCDs have their advantage that it is easier to specify the optimum damping of the damper by changing the opening ratio of the orifice. In this paper, 2-DOF nonlinear models are suggested for tuning a roller damper or a TLCD attached to a rotating wind turbine blade, ignoring the coupling between the blade and the tower. The decoupled optimization is verified by incorporating the optimized damper into a more sophisticated 13- DOF wind turbine model with due consideration of the coupled blade-tower-drivetrain vibrations, quasi-static aeroelasticity as well as a collective pitch controller. Performances of the dampers are compared in terms of the control efficiency and the practical applications. The results indicate that roller dampers and TLCDs at optimal tuning can effectively suppress the dynamic response of wind turbine blades.

  6. Oxygen mass transfer and scale-up studies in baffled roller bioreactors.

    Science.gov (United States)

    Nikakhtari, H; Song, W; Nemati, M; Hill, G A

    2014-02-01

    Oxygen mass transfer was studied in conventional, bead mill and baffled roller bioreactors. Using central composite rotational design, impacts of size, rotation speed and working volume on the oxygen mass transfer were evaluated. Baffled roller bioreactor outperformed its conventional and bead mill counterparts, with the highest k(L)a obtained in these configurations being 0.58, 0.19, 0.41 min(-1), respectively. Performances of the bead mill and baffled roller bioreactor were only comparable when a high bead loading (40%) was applied. Regardless of configuration increase in rotation speed and decrease in working volume improved the oxygen mass transfer rate. Increase in size led to enhanced mass transfer and higher k(L)a in baffled roller bioreactor (0.49 min(-1) for 2.2 L and 1.31 min(-1) for 55 L bioreactors). Finally, the experimentally determined k(L)a in the baffled roller bioreactors of different sizes fit reasonably well to an empirical correlation describing the k(L)a in terms of dimensionless numbers.

  7. Roller coaster-associated subarachnoid hemorrhage--report of 2 cases.

    Science.gov (United States)

    Rutsch, Sebastian; Niesen, Wolf-Dirk; Meckel, Stephan; Reinhard, Matthias

    2012-04-15

    The most common neurological injuries associated with roller coaster rides are subdural hematoma and cervical artery dissection. We report two cases of roller-coaster associated subarachnoid hemorrhage (SAH). A 40-year-old healthy man developed a strong, holocephalic headache during a roller coaster ride. SAH Hunt & Hess grade II and Fisher grade 3 was diagnosed. An underlying aneurysm of the anterior communicating artery was successfully treated with coil embolization. A 41-year-old female (smoker, otherwise healthy) experienced a sudden, strong headache and diplopia during a roller coaster ride. A perimesencephalic SAH (Hunt & Hess grade II, Fisher grade 3) was disclosed by a CT scan. No aneurysm was detected on angiography. Both patients were discharged without neurological disability. In conclusion, SAH is a rare but relevant differential diagnosis in cases of acute headache during roller coaster rides. Both aneurysmal and non-aneurysmal perimesencephalic SAH can occur. A combination of mechanical factors and excessive blood pressure rises in vulnerable persons is discussed.

  8. A practical approach for the scale-up of roller compaction process.

    Science.gov (United States)

    Shi, Weixian; Sprockel, Omar L

    2016-09-01

    An alternative approach for the scale-up of ribbon formation during roller compaction was investigated, which required only one batch at the commercial scale to set the operational conditions. The scale-up of ribbon formation was based on a probability method. It was sufficient in describing the mechanism of ribbon formation at both scales. In this method, a statistical relationship between roller compaction parameters and ribbon attributes (thickness and density) was first defined with DoE using a pilot Alexanderwerk WP120 roller compactor. While the milling speed was included in the design, it has no practical effect on granule properties within the study range despite its statistical significance. The statistical relationship was then adapted to a commercial Alexanderwerk WP200 roller compactor with one experimental run. The experimental run served as a calibration of the statistical model parameters. The proposed transfer method was then confirmed by conducting a mapping study on the Alexanderwerk WP200 using a factorial DoE, which showed a match between the predictions and the verification experiments. The study demonstrates the applicability of the roller compaction transfer method using the statistical model from the development scale calibrated with one experiment point at the commercial scale. Copyright © 2016 Elsevier B.V. All rights reserved.

  9. Nonlinear Dynamics Behaviors of a Rotor Roller Bearing System with Radial Clearances and Waviness Considered

    Institute of Scientific and Technical Information of China (English)

    Wang Liqin; Cui Li; Zheng Dezhi; Gu Le

    2008-01-01

    A rotor system supported by roller bearings displays very complicated nonlinear behaviors due to nonlinear Hertzian contact forces, radial clearances and bearing waviness. This paper presents nonlinear bearing forces of a roller bearing under four-dimensional loads and establishes 4-DOF dynamics equations of a rotor roller bearing system. The methods of Newmark-β and of Newton-Laphson are used to solve the nonlinear equations. The dynamics behaviors of a rigid rotor system are studied through the bifurcation, the Poincar bility caused by the quasi-periodic bifurcation, the periodic-doubling bifurcation and chaos routes as the rotational speed increases.Clearances, outer race waviness, inner race waviness, roller waviness, damping, radial forces and unbalanced forces-all these bring a significant influence to bear on the system stability. As the clearance increases, the dynamics behaviors become complicated with the number and the scale of instable regions becoming larger. The vibration frequencies induced by the roller bearing waviness and the orders of the waviness might cause severe vibrations. The system is able to eliminate non-periodic vibration by reasonable choice and optimization of the parameters.

  10. Tabletop Experimental Track for Magnetic Launch Assist

    Science.gov (United States)

    2000-01-01

    Marshall Space Flight Center's (MSFC's) Advanced Space Transportation Program has developed the Magnetic Launch Assist System, formerly known as the Magnetic Levitation (MagLev) technology that could give a space vehicle a running start to break free from Earth's gravity. A Magnetic Launch Assist system would use magnetic fields to levitate and accelerate a vehicle along a track at speeds up to 600 mph. The vehicle would shift to rocket engines for launch into orbit. Similar to high-speed trains and roller coasters that use high-strength magnets to lift and propel a vehicle a couple of inches above a guideway, a Magnetic Launch Assist system would electromagnetically propel a space vehicle along the track. The tabletop experimental track for the system shown in this photograph is 44-feet long, with 22-feet of powered acceleration and 22-feet of passive braking. A 10-pound carrier with permanent magnets on its sides swiftly glides by copper coils, producing a levitation force. The track uses a linear synchronous motor, which means the track is synchronized to turn the coils on just before the carrier comes in contact with them, and off once the carrier passes. Sensors are positioned on the side of the track to determine the carrier's position so the appropriate drive coils can be energized. MSFC engineers have conducted tests on the indoor track and a 50-foot outdoor track. The major advantages of launch assist for NASA launch vehicles is that it reduces the weight of the take-off, the landing gear, the wing size, and less propellant resulting in significant cost savings. The US Navy and the British MOD (Ministry of Defense) are planning to use magnetic launch assist for their next generation aircraft carriers as the aircraft launch system. The US Army is considering using this technology for launching target drones for anti-aircraft training.

  11. Hard α-Al2O3 Film Coating on Industrial Roller Using Aerosol Deposition Method

    Science.gov (United States)

    Seto, Naoki; Endo, Kazuteru; Sakamoto, Nobuo; Hirose, Shingo; Akedo, Jun

    2014-12-01

    It is well known that α-Al2O3 forms very hard, highly insulating, smooth films. There is demand for the use of such films instead of conventional hard, smooth films; For example, industrial rollers such as calendering rollers etc. are always required to have a harder and smoother surface than conventional rollers. Therefore, this work investigated the specification of α-Al2O3 films, e.g., their wear resistance and chemical stability, using various tests. This paper also discusses whether α-Al2O3 film can take the place of Cr plating film as a hard, smooth film by comparing their wear resistance and chemical stability.

  12. Optimal Driving of Large Belt Conveyor with Multi-roller Variable-Frequency Drive

    Institute of Scientific and Technical Information of China (English)

    FU Jun-qing; WANG Cong; LI Yu-jin

    2004-01-01

    in this paper, an electromechanically coupled mathematic model of multi-roller driving system for belt conveyor is set up, and the computing equations for dynamic displacement and dynamic tension of the conveyor are also formulated when the hoister is used for straining. Based on the belt conveyor of main inclined shaft in Chengzhuang coal mine, the driving torque, driving power and starting-speed characteristic of each electric motor are studied and measured when multi-roller variable-frequency drive (power distribution 2∶1) is used. The optimal control and the optimal starting-acceleration of the multi-roller variable-frequency drive are determined by a large number of industrial experiments and theoretical calculations.

  13. Roller Burnishing - A Cold Working Tool to Reduce Weld Induced Residual Stress

    Energy Technology Data Exchange (ETDEWEB)

    John Martin

    2002-02-19

    The possibility of stress corrosion cracking (SCC) in regions of tensile residual stress introduced by weld deposited material has been a concern where environmental effects can reduce component life. Roller burnishing, a form of mechanical cold-working, has been considered as a means of providing for residual stress state improvements. This paper provides a computational evaluation of the roller burnishing process to address the permanent deformation needed to introduce a desirable residual stress state. The analysis uses a series of incrementally applied pressure loadings and finite element methodology to simulate the behavior of a roller burnishing tool. Various magnitudes of applied pressure loadings coupled with different size plates and boundary conditions are examined to assess the degree and depth of the residual compressive stress state after cold working. Both kinematic and isotropic hardening laws are evaluated.

  14. Nanocrystalline, superhard, ductile ceramic coatings for roller-cone bit bearings

    Energy Technology Data Exchange (ETDEWEB)

    Namavar, F.; Colter, P.; Karimy, H. [Spire Corp., Bedford, MA (United States)] [and others

    1997-12-31

    The established method for construction of roller bits utilizes carburized steel, frequently with inserted metal bearing surfaces. This construction provides the necessary surface hardness while maintaining other desirable properties in the core. Protective coatings are a logical development where enhanced hardness, wear resistance, corrosion resistance, and surface properties are required. The wear properties of geothermal roller-cone bit bearings could be further improved by application of protective ceramic hard coatings consisting of nanometer-sized crystallites. Nanocrystalline protective coatings provide the required combination of hardness and toughness which has not been available thus far using traditional ceramics having larger grains. Increased durability of roller-cone bit bearings will ultimately reduce the cost of drilling geothermal wells through increased durability.

  15. ANALYSIS OF MOVEMENT RESISTANCE OF CONVEYOR BELT AND ROLLERS IN THE COAL MINE MYSŁOWICE-WESOŁA

    Directory of Open Access Journals (Sweden)

    Tadeusz OPASIAK

    2014-03-01

    Full Text Available The paper presents a study of new design of SAG rollers. The study focused on the measurement of static and dynamic resistance of rotating rollers and the impact of new construction on the power consumption of the conveyor. Rollers have been modified through the use of class C4 bearing seals and labyrinth seal U4Exp 62/65 with a cover 2LU4 of runner construction. Measurements of static and dynamic resistance of rotating rollers were made on a universal rollers test bench, and power measurements were carried out on a belt conveyor power supply system Gwarek 1200 No. TW in KWK Mysłowice-Wesoła

  16. Survey of tracking systems and rotary joints for coolant piping. Final report, August 15, 1978-August 14, 1978. [Includes patents

    Energy Technology Data Exchange (ETDEWEB)

    Furaus, J P; Gruchalla, M E; Sower, G D

    1980-01-01

    Problems were surveyed and evaluated with respect to solar tracking mechanisms and rotary joints for coolant piping. An analytical development of celestial mechanics, one- and two-axis tracking configurations and the effect of tracking accuracy versus collector efficiency are reported. Daily operational requirements and tracking modes were defined and evaluated. A literature and patent search on solar tracking technology was performed. Tracking system and control system performance specifications were determined. Alternative conceptual tracking approaches were defined and a cost and performance evaluation of a mechanical tracking concept was performed. Fluid coupling service specifications were determined. The cost and performance of several types of actuators and error detectors were evaluated with respect to solar tracking mechanisms.

  17. Simulation of accelerated strip cooling on the hot rolling mill run-out roller table

    Directory of Open Access Journals (Sweden)

    E.Makarov

    2016-07-01

    Full Text Available A mathematical model of the thermal state of the metal in the run-out roller table continuous wide hot strip mill. The mathematical model takes into account heat generation due to the polymorphic γ → α transformation of supercooled austenite phase state and the influence of the chemical composition of the steel on the physical properties of the metal. The model allows calculation of modes of accelerated cooling strips on run-out roller table continuous wide hot strip mill. Winding temperature calculation error does not exceed 20°C for 98.5 % of strips of low-carbon and low-alloy steels

  18. Design, development and evaluation of a divergent roller sizer for almond kernels

    Directory of Open Access Journals (Sweden)

    D Ghanbarian

    2015-09-01

    Full Text Available Introduction: Iran is one of the major producers of almonds. According to the statistics released by FAO (2011, Iran with more than 110000 tons of almonds is the third in rank throughout the world. However, most Iranian almonds are presented as an unsorted and unpackaged product. Some producers sort their products by hand which is very time-consuming and labor-intensive. So, there is an essential need for suitable grading and packaging machines especially for the export of almond kernels.Grading, which is sometimes called sorting, is basically separating the material in different homogenous groups according to its specific characteristics like size, shape, color and on the basis of quality. Weighing is one of the best methods for grading agricultural products based on size, but due to its high cost and complexity of operations, usage of weigh size sorting machines is practically limited. So, sizing of most agricultural products is accomplished based on their dimensional attributes such as diameter, length, thickness or a combination of them. Field study shows that recently vibrating sizing machines are used for grading almond kernels. This type of sizing machine is huge, expensive, noisy and it consumes a lot of energy. Thus, the main objective of the present study was the design, development and evaluation of a new prototype of an almond kernel sizing machine. Materials and methods: It is important that the machine could resolve defects of existing vibrating machines. It should provide efficient and cost effective sizing for a wide range of kernel sizes and shapes. Furthermore, it should be of simple construction and be able to accept manual feeding. Previously conducted experiments showed that the thickness of the kernel is the most appropriate dimension for its sizing. Among the different types of dimensional sizing machines, the divergent roller grader which grades the products based on their thickness is considered to be one of the simplest

  19. Design, development and evaluation of a divergent roller sizer for almond kernels

    Directory of Open Access Journals (Sweden)

    D Ghanbarian

    2015-09-01

    Full Text Available Introduction: Iran is one of the major producers of almonds. According to the statistics released by FAO (2011, Iran with more than 110000 tons of almonds is the third in rank throughout the world. However, most Iranian almonds are presented as an unsorted and unpackaged product. Some producers sort their products by hand which is very time-consuming and labor-intensive. So, there is an essential need for suitable grading and packaging machines especially for the export of almond kernels.Grading, which is sometimes called sorting, is basically separating the material in different homogenous groups according to its specific characteristics like size, shape, color and on the basis of quality. Weighing is one of the best methods for grading agricultural products based on size, but due to its high cost and complexity of operations, usage of weigh size sorting machines is practically limited. So, sizing of most agricultural products is accomplished based on their dimensional attributes such as diameter, length, thickness or a combination of them. Field study shows that recently vibrating sizing machines are used for grading almond kernels. This type of sizing machine is huge, expensive, noisy and it consumes a lot of energy. Thus, the main objective of the present study was the design, development and evaluation of a new prototype of an almond kernel sizing machine. Materials and methods: It is important that the machine could resolve defects of existing vibrating machines. It should provide efficient and cost effective sizing for a wide range of kernel sizes and shapes. Furthermore, it should be of simple construction and be able to accept manual feeding. Previously conducted experiments showed that the thickness of the kernel is the most appropriate dimension for its sizing. Among the different types of dimensional sizing machines, the divergent roller grader which grades the products based on their thickness is considered to be one of the simplest

  20. Fuzzy Reliability Design for the Interference Articulation of a Roller Shaft

    Institute of Scientific and Technical Information of China (English)

    2001-01-01

    With regard to function, the strengths for interference articulation of a roller shaft formed a series system. As the three strength reliabilities conditioned each other, there was a problem for the system reliability to apportion rationally. In fact, there was a transition from safety to deactivation. The state of structure was fuzziness which was in both safety and non-safety states. Therefore the reliability was a fuzzy event which considered the randomness for some design parameters and the fuzziness for the thresholds between generalized strength safety and deactivation. The mathematical model of fuzzy reliability design for the interference articulation of the roller shaft was presented. Eight design examples were calculated. ``

  1. The application of plasma-sprayed ceramic coatings on lift roller in float glass

    Institute of Scientific and Technical Information of China (English)

    2005-01-01

    Oxide ceramic was sprayed via high-energy plasma spray using MCrAlY manufactured with special technique as bond coating and oxide ceramic as top coating in this article. Investigation showed that the dense and highly adhesive coating could be obtained with optimized technique. After grinding and polishing, coating roughness was lower than 0. 2μm, which could meet the requirements of lift roller. After one year serv ice, molten Tin could not adhere to the ceramic coating,well it greatly alleviated its corrosion to the roller , kept the surface of oxide ceramic coating smooth and the improve the quality of glass due to the strengthened lift roll.

  2. Modelling of a mecanum wheel taking into account the geometry of road rollers

    Science.gov (United States)

    Hryniewicz, P.; Gwiazda, A.; Banaś, W.; Sękala, A.; Foit, K.

    2017-08-01

    During the process planning in a company one of the basic factors associated with the production costs is the operation time for particular technological jobs. The operation time consists of time units associated with the machining tasks of a workpiece as well as the time associated with loading and unloading and the transport operations of this workpiece between machining stands. Full automation of manufacturing in industry companies tends to a maximal reduction in machine downtimes, thereby the fixed costs simultaneously decreasing. The new construction of wheeled vehicles, using Mecanum wheels, reduces the transport time of materials and workpieces between machining stands. These vehicles have the ability to simultaneously move in two axes and thus more rapid positioning of the vehicle relative to the machining stand. The Mecanum wheel construction implies placing, around the wheel free rollers that are mounted at an angle 450, which allow the movement of the vehicle not only in its axis but also perpendicular thereto. The improper selection of the rollers can cause unwanted vertical movement of the vehicle, which may cause difficulty in positioning of the vehicle in relation to the machining stand and the need for stabilisation. Hence the proper design of the free rollers is essential in designing the whole Mecanum wheel construction. It allows avoiding the disadvantageous and unwanted vertical vibrations of a whole vehicle with these wheels. In the article the process of modelling the free rollers, in order to obtain the desired shape of unchanging, horizontal trajectory of the vehicle is presented. This shape depends on the desired diameter of the whole Mecanum wheel, together with the road rollers, and the width of the drive wheel. Another factor related with the curvature of the trajectory shape is the length of the road roller and its diameter decreases depending on the position with respect to its centre. The additional factor, limiting construction of

  3. Analysis of the Lateral Stability of a Truck on the NRC Curved Track Simulator

    Institute of Scientific and Technical Information of China (English)

    Dukkipati Rao V.

    1994-01-01

    The development of experimental facilities for rail vehicle testing at the NRC Centre for Surface Transportation Technology is being complemented by analytic studies. The purpose of this effort has been to gain insight into the dynamics of rail vehicles in order to guide the development of the Curved Track Simulator (CTS) and to establish an analytic framework for the design and interpretation of tests to be conducted on the CTS. The work described here represents an initial effort towards meeting these objectives.Parametric study results using linear model of freight truck on the CTS showed that (a) increasing roller radius increases critical speed (b) increasing the wheel initial cone angle will decrease the hunting speed (c) increasing the roller cant increases hunting speed (d) decrowning of the wheelset on the rollers will not effect the hunting speed but induces longitudinal destabilzing horizontal forces at the contact and (e) lozenging of wheelset on the rollers induces a yaw moment and the hunting speed decreases with increasing wheelset yaw angle.

  4. An engineering study on the enhanced control and operation of continuous manufacturing of pharmaceutical tablets via roller compaction.

    Science.gov (United States)

    Singh, Ravendra; Ierapetritou, Marianthi; Ramachandran, Rohit

    2012-11-15

    A novel manufacturing strategy based on continuous processing integrated with online monitoring tools coupled with efficient automatic feedback control system is highly desired for efficient Quality by Design (QbD) based manufacturing of the next generation of pharmaceutical products with optimal consumption of time, space and resources. In this manuscript, an efficient plant-wide control strategy for an integrated continuous pharmaceutical tablet manufacturing process via roller compaction has been designed in silico. The designed control system consists of five cascade control loops and three single control loops resulting in 42 controller tuning parameters. An effective controller parameter tuning strategy involving an ITAE method coupled with an optimization strategy has been proposed and the designed control system has been implemented in a first principle model-based flowsheet that was simulated in gPROMS (Process System Enterprise). The advanced techniques (e.g. anti-windup) have been employed to improve the performance of the control system. The ability of the control system to reject the unknown disturbances as well as to track the set point has been analyzed. Results demonstrated enhanced performance of critical quality attributes (CQAs) under closed-loop control compared to open-loop operation thus illustrating the potential of closed-loop feedback control in improving pharmaceutical manufacturing operations.

  5. Determinants of a simulated cross-country skiing sprint competition using V2 skating technique on roller skis.

    Science.gov (United States)

    Mikkola, Jussi; Laaksonen, Marko; Holmberg, Hans-Christer; Vesterinen, Ville; Nummela, Ari

    2010-04-01

    The present study investigated the performance-predicting factors of a simulated cross-country (XC) skiing sprint competition on roller skis, on a slow surface. Sixteen elite male XC skiers performed a simulated sprint competition (4 x 850 m heat with a 20-minute recovery) using V2 skating technique on an indoor tartan track. Heat velocities, oxygen consumption, and peak lactate were measured during or after the heats. Maximal skiing velocity was measured by performing a 30-m speed test. Explosive and maximal force production in the upper body was determined by bench press (BP). Subjects also performed maximal anaerobic skiing test (MAST) and the 2 x 2-km double poling (DP) test. The maximal velocity of MAST (VMAST) and velocities at 3 (V3), 5 (V5), 7 (V7) mmol.L lactate levels in MAST were determined. In the 2 x 2-km test, DP economy (VO2SUBDP) and maximal 2-km DP velocity (VDP2KM) were determined. The best single performance-predicting factors for the sprint performance were VDP2KM (r = 0.73, p skiing power (VMAST, p skiing economy (V3, V5, V7, p skiing sprint competition, whereas the aerobic characteristics become more important as the XC skiing sprint competition progressed. This study indicates that sprint skiers should emphasize sport-specific upper body training, and training skiing economy at high speeds.

  6. Dropping a Particle Out of a Roller Coaster

    Science.gov (United States)

    2014-04-24

    Particle launched from a parabola For a parabolic curve that starts at the origin with zero slope, y = Ax2 with A > 0, the equation determining the...track of known shape. Analytic solutions have been found and discussed for launch off a horizontal ramp, an inclined plane, a parabola , and a

  7. Effect of applying modes of the polymer microneedle-roller on the permeation of L-ascorbic acid in rats.

    Science.gov (United States)

    You, Sung-Kyun; Noh, Young-Wook; Park, Hyoun-Hyang; Han, Manhee; Lee, Seung S; Shin, Sang-Chul; Cho, Cheong-Weon

    2010-01-01

    Despite the advantages of drug delivery through skin, transdermal drug delivery is only used with a small subset of drugs because most compounds cannot cross the skin at therapeutically useful rates. Recently, a new concept known as microneedle was introduced and could be used to pierce effectively to deliver drugs using micron-sized needles in a minimally invasive and painless manner. In this study, the polymer microneedle-roller was fabricated so that it can be applied into the permeation of L-ascorbic acid. Moreover, a recent publication suggested the possibility of ascorbic acid 2-phosphate as a hair restorer; hence, this study was carried out to check the effect of L-ascorbic acid itself on the hair growing rate in rats according to the presence of various application frequencies of the polymer microneedle-roller. When the polymer microneedle-roller was applied nine times with four directions into rat's shaved skin, the permeation of L-ascorbic acid increased by 10.54-fold compared to that of the absence of the polymer microneedle-roller. The histological examination revealed that the skin pretreated with various application frequencies of the polymer microneedle-roller had more transport pathways. The faster hair growing phenomenon was observed in the presence of polymer microneedle-roller compared to the absence of the polymer microneedle-roller.

  8. Visualizing asphalt roller trajectories in context: acquiring, processing, and representing sensor readings

    NARCIS (Netherlands)

    Vasenev, Alexandr Nikolajevitsj

    2015-01-01

    The asphalt compaction process relies heavily on the skills and knowledge of roller operators who act alongside other stakeholders involved in asphalt paving. It is essential that these construction specialists: (1) are adequately informed about the initial temperature distribution of the asphalt la

  9. Liikluseksperimendis edestas roller tsiklit ja teisi osalejaid : “2 vs 4″

    Index Scriptorium Estoniae

    2010-01-01

    12. mail toimus Tallinnas keskkonnasõbraliku motonäituse MoMa raames eksperiment, milles osalesid jalgratas, elektriroller, roller, mootorratas ja auto. Marsruudil Miidurand-Nõmme üritati hommikuses liikluses välja selgitada, milline neist sõiduvahendest kõige edukamalt toime tuleb

  10. Working condition and health hazards in beedi rollers residing in the urban slums of Mumbai

    Directory of Open Access Journals (Sweden)

    Rupali V Sabale

    2012-01-01

    Full Text Available Background: Beedi rollers are exposed to unburnt tobacco dust through cutaneous and pharyngeal route. They are not aware of their rights. Studies have been conducted on beedi workers but not many studies are carried out in urban areas. Thus, study was carried out to understand working condition and health hazards in beedi workers residing in the urban slums of Mumbai and to know whether beedi roller are in better condition in urban areas. Aim: To study working condition and health hazard in beedi rollers in the urban slums. Materials and Methods: Descriptive, cross-sectional, community based study was carried in the urban slums of Mumbai with population of 8985 from April 2011 to June 2011. With snow balling sampling technique, 52 beedi workers were interviewed regarding their socio-economic status, working conditions and health problems after informed consent. Data entry and statistical analysis were performed using the SPSS windows version 14.0 software. Results: The mean age was 45 years with SD of 12 years. All were Hindu females. Around 42.31% were illiterate. Mean years of service were 30 years and they work on an average for eight hours. Children were not involved in beedi rolling. Most common morbidity was fatigue. None were aware of the benefits provided for them. Awareness regarding health hazard and safety measures was poor. Conclusions: The working condition of beedi rollers in the urban areas is not favourable.

  11. The Dynamics of Plant Closings: An Extended Emotional Roller Coaster Ride.

    Science.gov (United States)

    Hurst, Joe B.; Shepard, John W.

    1986-01-01

    Millions of United States' workers are unemployed, many of them dislocated from their jobs and careers by extended layoffs, drastic manpower reductions, and plant closings. Describes a model of the emotional roller coaster ride taken by employees displaced by a plant closing and suggests approaches to helping them and their families. (Author/ABB)

  12. The Roller-Coaster of Experiences: Becoming the Parent of a Deaf Child

    Science.gov (United States)

    Bosteels, Sigrid; Van Hove, Geert; Vandenbroeck, Michel

    2012-01-01

    When early testing indicates a hearing loss, parents find themselves on a roller-coaster of experiences leaving little time or space for reflection. This study is based on interviews with families in the Flemish region of Belgium, one of the earliest in the world to introduce universal neonatal screening for hearing loss. Starting from a…

  13. Acceleration in One, Two, and Three Dimensions in Launched Roller Coasters

    Science.gov (United States)

    Pendrill, Ann-Marie

    2008-01-01

    During a roller coaster ride, the body experiences acceleration in three dimensions. An accelerometer can measure and provide a graph of the forces on the body during different parts of a ride. To couple the experience of the body to pictures of the ride and an analysis of data can contribute to a deeper understanding of Newton's laws. This…

  14. Application of Design Failure Modes and Effect Analysis (DFMEA to Vertical Roller Mill Gearbox

    Directory of Open Access Journals (Sweden)

    Gaurav J. Pawar 1 ,

    2015-12-01

    Full Text Available Design FMEA is structured method of identifying potential failure modes and providing corrective actions before first production run occurs. This paper aims to provide probable causes of failure, levels of effects of failure and corrective actions to be taken in the design phase for BevelPlanetary Vertical Roller Mill Gearbox.

  15. 3000-HP Roller Gear Transmission Development Program, Volume II. Design Report

    Science.gov (United States)

    1975-12-01

    INDICATOR DUAL INDICATOR Figure 73. Engine Torquemeter System. 142 z o > td Vm...9.5331 •This roller is not corrected to minimize si Idi ng.as the two loading conditions vary greatly. HZj In the following calculations large

  16. HYDRAULIC ACTIVE GUIDE ROLLER SYSTEM FOR HIGH-SPEED ELEVATOR BASED ON FUZZY CONTROLLER

    Institute of Scientific and Technical Information of China (English)

    FENG Yonghui; ZHANG Jianwu

    2007-01-01

    Increase of elevator speed brings about amplified vibrations of high-speed elevator. In order to reduce the horizontal vibrations of high-speed elevator, a new type of hydraulic active guide roller system based on fuzzy logic controller is developed. First the working principle of the hydraulic guide system is introduced, then the dynamic model of the horizontal vibrations for elevator cage with active guide roller system and the mathematical model of the hydraulic system are given. A fuzzy logic controller for the hydraulic system is designed to control the hydraulic actuator. To improve the control performance, preview compensation for the controller is provided. Finally, simulation and experiments are executed to verify the hydraulic active guide roller system and the control strategy. Both the simulation and experimental results indicate that the hydraulic active guide roller system can reduce the horizontal vibrations of the elevator effectively and has better effects than the passive one, and the fuzzy logic controller with preview compensation can give superior control performance.

  17. Edgewise vibration control of wind turbine blades using roller and liquid dampers

    DEFF Research Database (Denmark)

    Zhang, Zili; Nielsen, Søren R.K.

    2014-01-01

    model with due consideration of the coupled blade-tower-drivetrain vibrations, quasi-static aeroelasticity as well as a collective pitch controller. Performances of the dampers are compared in terms of the control efficiency and the practical applications. The results indicate that roller dampers...

  18. Kinematic and dynamic modeling and approximate analysis of a roller chain drive

    DEFF Research Database (Denmark)

    Fuglede, Niels; Thomsen, Jon Juel

    2016-01-01

    A simple roller chain drive consisting of two sprockets connected by tight chain spans is investigated. First, a kinematic model is presented which include both spans and sprockets. An approach for calculating the chain wrapping length is presented, which also allows for the exact calculation of ...

  19. Molecular Dynamics Simulations of the Roller Nanoimprint Process: Adhesion and Other Mechanical Characteristics

    Directory of Open Access Journals (Sweden)

    Fang Te-Hua

    2009-01-01

    Full Text Available Abstract Molecular dynamics simulations using tight-binding many body potential are carried out to study the roller imprint process of a gold single crystal. The effect of the roller tooth’s taper angle, imprint depth, imprint temperature, and imprint direction on the imprint force, adhesion, stress distribution, and strain are investigated. A two-stage roller imprint process was obtained from an imprint force curve. The two-stage imprint process included the imprint forming with a rapid increase of imprint force and the unloading stage combined with the adhesion stage. The results show that the imprint force and adhesion rapidly increase with decreasing taper angle and increasing imprint depth. The magnitude of the maximum imprint force and the time at which this maximum occurs are proportional to the imprint depth, but independent of the taper angle. In a comparison of the imprint mechanisms with a vertical imprint case, while high stress and strain regions are concentrated below the mold for vertical imprint, they also occur around the mold in the case of roller imprint. The regions were only concentrated on the substrate atoms underneath the mold in vertical imprint. Plastic flow increased with increasing imprint temperature.

  20. A study on the fabrication of main scale of linear encoder using continuous roller imprint method

    Science.gov (United States)

    Fan, Shanjin; Shi, Yongsheng; Yin, Lei; Feng, Long; Liu, Hongzhong

    2013-10-01

    Linear encoder composed of main and index scales has an extensive application in the field of modern precision measurement. The main scale is the key component of linear encoder as measuring basis. In this article, the continuous roller imprint technology is applied to the manufacturing of the main scale, this method can realize the high efficiency and low cost manufacturing of the ultra-long main scale. By means of the plastic deformation of the soft metal film substrate, the grating microstructure on the surface of the cylinder mold is replicated to the soft metal film substrate directly. Through the high precision control of continuous rotational motion of the mold, ultra-long high precision grating microstructure is obtained. This paper mainly discusses the manufacturing process of the high precision cylinder mold and the effects of the roller imprint pressure and roller rotation speed on the imprint replication quality. The above process parameters were optimized to manufacture the high quality main scale. At last, the reading test of a linear encoder contains the main scale made by the above method was conducted to evaluate its measurement accuracy, the result demonstrated the feasibility of the continuous roller imprint method.

  1. "Roller coaster maneuver via lateral orbital approach" for reduction of isolated zygomatic arch fractures.

    Science.gov (United States)

    Pilanci, Ozgur; Basaran, Karaca; Datli, Asli; Kuvat, Samet Vasfi

    2013-11-01

    Numerous techniques have been reported for the reduction of zygomatic arch fractures. In this article, we aimed to describe a technique we named as "roller coaster maneuver via lateral orbital approach" to closed reduction of the isolated-type zygomatic arch fractures. Surgical outcomes of 14 patients treated with this method were outlined.

  2. The Dynamics of Plant Closings: An Extended Emotional Roller Coaster Ride.

    Science.gov (United States)

    Hurst, Joe B.; Shepard, John W.

    1986-01-01

    Millions of United States' workers are unemployed, many of them dislocated from their jobs and careers by extended layoffs, drastic manpower reductions, and plant closings. Describes a model of the emotional roller coaster ride taken by employees displaced by a plant closing and suggests approaches to helping them and their families. (Author/ABB)

  3. The Roller-Coaster of Experiences: Becoming the Parent of a Deaf Child

    Science.gov (United States)

    Bosteels, Sigrid; Van Hove, Geert; Vandenbroeck, Michel

    2012-01-01

    When early testing indicates a hearing loss, parents find themselves on a roller-coaster of experiences leaving little time or space for reflection. This study is based on interviews with families in the Flemish region of Belgium, one of the earliest in the world to introduce universal neonatal screening for hearing loss. Starting from a…

  4. Acceleration in One, Two, and Three Dimensions in Launched Roller Coasters

    Science.gov (United States)

    Pendrill, Ann-Marie

    2008-01-01

    During a roller coaster ride, the body experiences acceleration in three dimensions. An accelerometer can measure and provide a graph of the forces on the body during different parts of a ride. To couple the experience of the body to pictures of the ride and an analysis of data can contribute to a deeper understanding of Newton's laws. This…

  5. Micromechanical study of the effect of inclusions on fatigue failure in a roller bearing

    DEFF Research Database (Denmark)

    Cerullo, Michele; Tvergaard, Viggo

    2015-01-01

    of the most commonly used bearing steels, AISI 52100, and two different types of inclusions are considered. The macroscopic stress histories applied correspond to either a Hertzian or an elastohydrodynamic (EHL) contact pressure distribution under the rollers. Findings - The paper shows that sub...

  6. Granule fraction inhomogeneity of calcium carbonate/sorbitol in roller compacted granules

    DEFF Research Database (Denmark)

    Bacher, Charlotte; Olsen, P.M.; Bertelsen, P.;

    2008-01-01

    The granule fraction inhomogeneity of roller compacted granules was examined on mixtures of three different morphologic forms of calcium carbonate and three particle sizes of sorbitol. The granule fraction inhomogeneity was determined by the distribution of the calcium carbonate in each of the 10...

  7. A Roller Bearing Fault Diagnosis Method Based on LCD Energy Entropy and ACROA-SVM

    Directory of Open Access Journals (Sweden)

    HungLinh Ao

    2014-01-01

    Full Text Available This study investigates a novel method for roller bearing fault diagnosis based on local characteristic-scale decomposition (LCD energy entropy, together with a support vector machine designed using an Artificial Chemical Reaction Optimisation Algorithm, referred to as an ACROA-SVM. First, the original acceleration vibration signals are decomposed into intrinsic scale components (ISCs. Second, the concept of LCD energy entropy is introduced. Third, the energy features extracted from a number of ISCs that contain the most dominant fault information serve as input vectors for the support vector machine classifier. Finally, the ACROA-SVM classifier is proposed to recognize the faulty roller bearing pattern. The analysis of roller bearing signals with inner-race and outer-race faults shows that the diagnostic approach based on the ACROA-SVM and using LCD to extract the energy levels of the various frequency bands as features can identify roller bearing fault patterns accurately and effectively. The proposed method is superior to approaches based on Empirical Mode Decomposition method and requires less time.

  8. Modeling waves, currents and sandbars on natural beaches: The effect of surface rollers

    NARCIS (Netherlands)

    Ribas, F.; de Swart, H.E.; Calvete, D.; Falqués, A.

    2011-01-01

    A morphodynamic model has been extended to gain more fundamental knowledge about the formation of nearshore sand bars. The model describes feedbacks between waves, rollers, depth-averaged currents and bed evolution, so that self-organized processes can develop. Offshore wave, wind and tide condition

  9. Design study of a continuously variable roller cone traction CVT for electric vehicles

    Science.gov (United States)

    Mccoin, D. K.; Walker, R. D.

    1980-01-01

    Continuously variable ratio transmissions (CVT) featuring cone and roller traction elements and computerized controls are studied. The CVT meets or exceeds all requirements set forth in the design criteria. Further, a scalability analysis indicates the basic concept is applicable to lower and higher power units, with upward scaling for increased power being more readily accomplished.

  10. 77 FR 12326 - Tapered Roller Bearings From China; Scheduling of a Full Five-Year Review

    Science.gov (United States)

    2012-02-29

    ... From the Federal Register Online via the Government Publishing Office INTERNATIONAL TRADE COMMISSION Tapered Roller Bearings From China; Scheduling of a Full Five- Year Review AGENCY: United States... responses to its notice of institution of the subject five-year review were such that a full review pursuant...

  11. 77 FR 16859 - Tapered Roller Bearings From China; Scheduling of a Full Five-Year Review

    Science.gov (United States)

    2012-03-22

    ... From the Federal Register Online via the Government Publishing Office INTERNATIONAL TRADE COMMISSION Tapered Roller Bearings From China; Scheduling of a Full Five- Year Review AGENCY: United States... Commission determined that responses to its notice of institution of the subject five-year review were such...

  12. 基于双轴磁强计及GPS的滚转角测量方法%Method to measure roll angle by two-axis magnetometer and GPS

    Institute of Scientific and Technical Information of China (English)

    李冰; 霍鹏飞; 祁克玉

    2012-01-01

    In order to measure the roll angle of high-speed rolling projectile in a high-dynamic ballistic trajectory, a method based on GPS and two-axis magnetometer is proposed. With the speed information measurement of GPS and two-axis magnetometer, the roll angel of the projectile in flight is solved in real time with the good vector properties of geomagnetic field. Simulation results show that the method of roll angle measurement has a high accuracy.and can be applied to the roll angel measurement of high-speed rolling projectiles in a high-dynamic ballistic trajectory.%针对高速旋转弹丸在高动态弹道环境下的滚转角测量难度大,精度低等问题,提出了基于双轴磁强计及GPS的滚转角测量方法.该方法利用地磁场良好的矢量特性,利用双轴磁强计和GPS速度信息的量测,实时解算弹丸飞行过程中的滚转角.仿真结果表明,该滚转角测量方法精度较高,能应用于弹丸在高动态、高过载弹道环境下的滚转角测量.

  13. NUMERICAL STUDY OF INFLUENCE OF MUTUAL SLEWIG OF ROLLER BEARING RINGS ON THE PRINCIPAL STRESSES AT CONTACT AREA

    Directory of Open Access Journals (Sweden)

    Lenka JAKUBOVIČOVÁ

    2014-09-01

    Full Text Available Article deals with influence of mutual slewing of roller bearing rings on the principal stresses and their distribution at the contact area. Profile of rolling element is logarithmic. Roller bearing has been loaded by maximum specified load only in radial direction according to the ISO/TS 16281. In practice, the real roller bearings are not loaded only in the radial direction. Therefore, the angle alfa has been gradually slewed from alfa = 0' to 8' and equivalent principal stresses have been evaluated. This change influenced on contact conditions and contact stress distribution has changed.

  14. Rolling Contact Fatigue Life of Steel Rollers Treated by Cavitation Peening and Shot Peening

    Science.gov (United States)

    Seki, Masanori; Soyama, Hitoshi; Kobayashi, Yuji; Gowa, Daisuke; Fujii, Masahiro

    The purpose of this study is to investigate the influence of peening on the rolling contact fatigue (RCF) life of steel rollers. First, steel rollers were treated by three types of peenings to ensure the same surface roughness of peened rollers. One is the cavitation peening (CP) used a cavitating jet in water with an injection pressure of 30 MPa, and the others are the fine particle peening (FPP) with a shot diameter of 0.1 mm and the normal shot peening (NSP) with a shot diameter of 0.3 mm. The surface hardness and the surface compressive residual stress of the steel rollers were increased by all the peenings. In particular, they were most increased by the FPP. On the other hand, the work-hardened depth due to the CP and the NSP was larger than that due to the FPP. As a result of the RCF tests, the RCF lives of the steel rollers were improved by all the peenings, and they were most improved by the NSP. Judging from the pmax - N curves and the [A(σy/√3 HV)]max - N curves, the improvement in RCF lives due to the FPP depended heavily on the increase in surface hardness due to that, and the effects of the CP and the NSP on the RCF were equivalent under the same surface roughness and the same surface hardness. It follows from these that the surface treatment condition should be selected according to the rolling contact conditions and the failure modes of machine elements.

  15. Dynamic Modeling of a Roller Chain Drive System Considering the Flexibility of Input Shaft

    Institute of Scientific and Technical Information of China (English)

    XU Lixin; YANG Yuhu; CHANG Zongyu; LIU Jianping

    2010-01-01

    Roller chain drives are widely used in various high-speed, high-load and power transmission applications, but their complex dynamic behavior is not well researched. Most studies were only focused on the analysis of the vibration of chain tight span, and in these models, many factors are neglected. In this paper, a mathematical model is developed to calculate the dynamic response of a roller chain drive working at constant or variable speed condition. In the model, the complete chain transmission with two sprockets and the necessary tight and slack spans is used. The effect of the flexibility of input shaft on dynamic response of the chain system is taken into account, as well as the elastic deformation in the chain, the inertial forces, the gravity and the torque on driven shaft. The nonlinear equations of movement are derived from using Lagrange equations and solved numerically. Given the center distance and the two initial position angles of teeth on driving and driven sprockets corresponding to the first seating roller on each side of the tight span, dynamics of any roller chain drive with two sprockets and two spans can be analyzed by the procedure. Finally, a numerical example is given and the validity of the procedure developed is demonstrated by analyzing the dynamic behavior of a typical roller chain drive. The model can well simulate the transverse and longitudinal vibration of the chain spans and the torsional vibration of the sprockets. This study can provide an effective method for the analysis of the dynamic characteristics of all the chain drive systems.

  16. DETERMINATION OF ADHESIVE STRENGTH LAYER’S ROLLER COMPACTED CONCRETE THE METHOD AXIAL EXTENSION

    Directory of Open Access Journals (Sweden)

    Tang Van Lam

    2017-07-01

    Full Text Available Roller compacted concrete for the construction of hydraulic and hydroelectric buildings is a composite material, which consists of a binder, fine aggregate (sand, coarse aggregate (gravel or crushed stone, water and special additives that provide the desired concrete workability and impart the required concrete performance properties. Concrete mixture is prepared at from concrete mixing plants strictly metered quantities of cement, water, additives and graded aggregates, whereupon they are delivered to the site laying Mixer Truck and sealing layers with each stack layer. The advantages of roller compaction technology should include the reduction of construction time, which allows fast commissioning construction projects, as well as reduce the amount of investment required. One of the main problems encountered in the process of roller compaction of the concrete mix is the need to provide the required adhesion strength between layers of concrete. This paper presents a method for determining the strength of adhesion between the concrete layers of different ages roller compacted concrete using axial tension. This method makes it possible to obtain objective and accurate results with a total thickness of layers of compacted concrete of up to 300…400 mm. Results from this method, studies have shown that the value of strength between the concrete layers in addition to the composition of the concrete and adhesion depends on the quality and the parallel end surfaces of the cylinder-models, which are mounted steel plates for axial tension, as well as the state of the contact surfaces of the concrete layer. The method can be used to determine the strength of interlayer adhesion in roller compacted concrete, which are used in the construction of dams and other hydraulic structures.

  17. Optimization Controller for Mechatronic Sun Tracking System to Improve Performance

    Directory of Open Access Journals (Sweden)

    Mustafa Engin

    2013-01-01

    Full Text Available An embedded system that contains hardware and software was developed for two-axis solar tracking system to improve photovoltaic panel utilization. The hardware section of the embedded system consists of a 32-bit ARM core microcontroller, motor driver circuits, a motion control unit, pyranometer, GPS receiver, and an anemometer. The real-time control algorithm enables the solar tracker to operate automatically without external control as a stand-alone system, combining the advantages of the open-loop and the closed-loop control methods. The pyranometer is employed to continuously send radiation data to the controller if the measured radiation is above the lower radiation limit the photovoltaic panel can generate power, guaranteeing the solar tracking process to be highly efficient. The anemometer is utilized in the system to ensure that the solar tracking procedure halts under high wind speed conditions to protect the entire system. Latitude, longitude, altitude, date, and real-time clock data are provided by GPS receiver. The algorithm calculates solar time using astronomical equations with GPS data and converts it to pulse-width modulated motor control signal. The overall objective of this study is to develop a control algorithm that improves performance and reliability of the two-axis solar tracker, focusing on optimization of the controller board, drive hardware, and software.

  18. Long-Life, Oil-Free, Light-Weight, Multi-Roller Traction Drives for Planetary Vehicle Surface Exploration Project

    Data.gov (United States)

    National Aeronautics and Space Administration — A multi-roller "oil free" traction drive is under development for use on vehicles used in hostile environments like those that will be encountered on planetary...

  19. Long-Life, Oil-Free Polymeric, Multi-Roller Traction Drives for Planetary Vehicle Surface Exploration Project

    Data.gov (United States)

    National Aeronautics and Space Administration — Multi-roller traction drives have several advantages relative to geared units for aerospace and commercial drive applications. Among these are zero backlash, low...

  20. Fire ants protect mealybugs against their natural enemies by utilizing the leaf shelters constructed by the leaf roller Sylepta derogata.

    Science.gov (United States)

    Zhou, Aiming; Zeng, Ling; Lu, Yongyue; Xu, Yijuan; Liang, Guangwen

    2012-01-01

    The importance of mutualism is receiving more attention in community ecology. In this study, the fire ant Solenopsis invicta was found to take advantage of the shelters constructed by the leaf roller Sylepta derogata to protect mealybugs (Phenacoccus solenopsis) against their natural enemies. This protective effect of fire ant tending on the survival of mealybugs in shelters was observed when enemies and leaf rollers were simultaneously present. Specifically, fire ants moved the mealybugs inside the shelters produced by S. derogata on enemy-infested plants. Compared with that in plants without ants, the survival of mealybugs in shelters in the presence of natural enemies in plants with ants markedly improved. Both the protection of ants and the shelters provided by leaf rollers did not affect the survival of mealybugs in the absence of enemies in plants. Ants and leaf rollers significantly improved the survival of mealybugs in predator-infested plants, whereas no such improvement was observed in parasitoid-infested ones.

  1. A Method for Incipient Fault Diagnosis of Roller Bearings Based on the Wavelet Transform Correlation Filter and Hilbert Transform

    Institute of Scientific and Technical Information of China (English)

    ZENG Qing-hu; QIU Jing; LIU Guan-jun

    2007-01-01

    Noise is the biggest obstacle that makes the incipient fault diagnosis results of roller bearings uncorrected; a new method for diagnosing incipient fault of roller bearings based on the Wavelet Transform Correlation Filter and Hilbert Transform was proposed. First, the weak fault information features are picked up from the roller bearings fault vibration signals by use of a de-noising characteristic of the Wavelet Transform Correlation Filter as the preprocessing of the Hilbert Envelope Analysis. Then, in order to get fault features frequency, de-noised wavelet coefficients of high scales which represent high frequency signal were analyzed by Hilbert Envelope Spectrum Analysis. The simulation signals and diagnosing examples analysis results reveal that the proposed method is more effective than the method of direct wavelet coefficients-Hilbert Transform in de-noising and clarifying roller bearing incipient fault.

  2. Acute, fatal Sarcocystis calchasi-associated hepatitis in Roller pigeons (Columbia livia f. dom.) at Philadelphia Zoo

    Science.gov (United States)

    Four Roller pigeons (Columba livia f. dom.) at the Philadelphia Zoo died suddenly. Necropsy examination revealed macroscopic hepatitis. Microscopically, the predominant lesions were in liver, characterized with necrosis and mixed cell inflammatory response. Sarcocystis calchasi-like schizonts and fr...

  3. Comparing a spray boom to a roller-wiper system for a single-passenger four-wheeler

    Science.gov (United States)

    James D. Haywood; Richard Hallman

    1992-01-01

    The ability of spray booms and carpet-covered roller-wipers mounted on four-wheelers to apply herbicides on pine plantings sites was tested with the following treatments: spray boom application of 0.31 kg (0.69 lb) acid equivalent glyphosate with 0.08 kg (0.18 lb) active ingredient sulfometuron in 215 liters of water/ha (23 gallons/acre) and roller-wiping the...

  4. Miniature Two-Axis Joystick Controller

    Science.gov (United States)

    Hollow, R.

    1983-01-01

    Novel movable-button-actuated self-centering controller uses optoelectronics to produce X and Y signals for aircraft control. In addition to be extremely compact, device puts our voltages having high signal-to-noise ratio, especially at critical center position where in many controllers this ratio is poorest. Combination of new saddle-shaped button and positive centering gives "feel" and "breakout" met with pilot approval.

  5. Two-axis magnetic field sensor

    Science.gov (United States)

    Jander, Albrecht (Inventor); Nordman, Catherine A. (Inventor); Qian, Zhenghong (Inventor); Smith, Carl H. (Inventor)

    2006-01-01

    A ferromagnetic thin-film based magnetic field sensor with first and second sensitive direction sensing structures each having a nonmagnetic intermediate layer with two major surfaces on opposite sides thereof having a magnetization reference layer on one and an anisotropic ferromagnetic material sensing layer on the other having a length in a selected length direction and a smaller width perpendicular thereto and parallel to the relatively fixed magnetization direction. The relatively fixed magnetization direction of said magnetization reference layer in each is oriented in substantially parallel to the substrate but substantially perpendicular to that of the other. An annealing process is used to form the desired magnetization directions.

  6. Designing Drops, Loops, and Hills: The Physics behind Roller Coaster Design

    Science.gov (United States)

    Christiana, Katharyn; Ilie, Carolina

    2013-03-01

    Almost everyone has seen a roller coaster at one time in their life. They range in type from old wooden coasters from decades passes to modern machines made of steel that allow you to stand up while riding. The basic physics behind these machines is relatively simple, but in the modern world we strive to design bigger and better machines that push the human body and the laws of physics to their limits. But how do the designers of these rides maintain the balance between making riders feel like they're on the brink of death while keeping them completely safe? The answer can be found in basic physics and mechanical engineering. This is a part of the honors thesis that focuses on the mechanical principles applied in roller coaster design. The theoretical part of the thesis will be complemented by a full small scale ride design.

  7. Roller Profile Online Measurement Based on Ultrasonic Circulation Pulse-echo Technology

    Institute of Scientific and Technical Information of China (English)

    WEN Shu-hui; XU Feng-rong

    2007-01-01

    In order to meet the high precision requirement of wide steel strip in industry field, a novel online measurement of roller profile based on sonic circulation and pulse-echo technology was introduced. All kinds of the factors influencing the accuracy of roller profile online measurement were analyzed in detail and error compensation analysis of system was accordingly presented. In order to reduce count error, field program gate array(FPGA) was introduced and a highprecision data acquisition system was designed based on digital phase-shift technology. Experiments indicate that the standard deviation of measure data was 7.27 μm, which showed the feasibility and validity of the proposed method, and realized the roll profile measurement with high precision.

  8. Cancer caregivers online: hope, emotional roller coaster, and physical/emotional/psychological responses.

    Science.gov (United States)

    Klemm, Paula; Wheeler, Erlinda

    2005-01-01

    The demands placed on cancer caregivers are well documented. Support for informal caregivers has been shown to increase hope and decrease psychosocial morbidity. The Internet is a readily available means of support for cancer caregivers, however little research on online support for informal caregivers of cancer patients exists. Descriptive statistics and qualitative analysis were used to evaluate messages posted over a 2-month period on an online cancer caregiver listserv. Three major themes emerged from the data: hope, emotional roller coaster, and physical/emotional/psychological responses. Supportive and hopeful statements prevailed among online participants in the current study. However, subjects also described the emotional roller coaster associated with caregiving. Emotional/physical/psychological responses included anger, weakness, exhaustion, grief, and sadness. Outcome research is needed to help evaluate the efficacy of online support for caregivers. Findings in this study can help nurses focus on some problems common to caregivers of cancer patients and plan appropriate interventions and research.

  9. Resolution of sudden sensorineural hearing loss following a roller coaster ride.

    Science.gov (United States)

    Kumar, Aman; Sinha, Amrita; Al-Waa, Ahmad M

    2011-07-01

    We report a case of sudden unilateral sensorineural hearing loss of sudden onset during an aeroplane flight, which completely resolved during a roller coaster ride at Alton Towers theme park. A review of the literature concerning sudden idiopathic sensorineural hearing loss and spontaneous resolution are discussed. Initially, pure-tone audiometry showed a profound sensorineural hearing loss in the right ear and mild sensorineural hearing loss in the left ear (of note, the hearing was normal prior to the episode). Following resolution of the patient's symptoms during a roller coaster ride, pure-tone audiometry showed normal hearing thresholds in both ears. Sudden sensorineural hearing loss is a symptom of cochlear injury and the mechanism of the patient's symptoms was attributed to a patent cochlear aqueduct.

  10. Resolution of Sudden Sensorineural Hearing Loss Following a Roller Coaster Ride

    OpenAIRE

    Kumar, Aman; Sinha, Amrita; Al-Waa, Ahmad M.

    2011-01-01

    We report a case of sudden unilateral sensorineural hearing loss of sudden onset during an aeroplane flight, which completely resolved during a roller coaster ride at Alton Towers theme park. A review of the literature concerning sudden idiopathic sensorineural hearing loss and spontaneous resolution are discussed. Initially, pure-tone audiometry showed a profound sensorineural hearing loss in the right ear and mild sensorineural hearing loss in the left ear (of note, the hearing was normal p...

  11. Optimization of Spherical Roller Bearing Design Using Artificial Bee Colony Algorithm and Grid Search Method

    Science.gov (United States)

    Tiwari, Rajiv; Waghole, Vikas

    2015-07-01

    Bearing standards impose restrictions on the internal geometry of spherical roller bearings. Geometrical and strength constraints conditions have been formulated for the optimization of bearing design. The long fatigue life is one of the most important criteria in the optimum design of bearing. The life is directly proportional to the dynamic capacity; hence, the objective function has been chosen as the maximization of dynamic capacity. The effect of speed and static loads acting on the bearing are also taken into account. Design variables for the bearing include five geometrical parameters: the roller diameter, the roller length, the bearing pitch diameter, the number of rollers, and the contact angle. There are a few design constraint parameters which are also included in the optimization, the bounds of which are obtained by initial runs of the optimization. The optimization program is made to run for different values of these design constraint parameters and a range of the parameters is obtained for which the objective function has a higher value. The artificial bee colony algorithm (ABCA) has been used to solve the constrained optimized problem and the optimum design is compared with the one obtained from the grid search method (GSM), both operating independently. Both the ABCA and the GSM have been finally combined together to reach the global optimum point. A constraint violation study has also been carried out to give priority to the constraint having greater possibility of violations. Optimized bearing designs show a better performance parameter with those specified in bearing catalogs. The sensitivity analysis of bearing parameters has also been carried out to see the effect of manufacturing tolerance on the objective function.

  12. Resolution of Sudden Sensorineural Hearing Loss Following a Roller Coaster Ride

    OpenAIRE

    Kumar, Aman; Sinha, Amrita; Al-Waa, Ahmad M.

    2011-01-01

    We report a case of sudden unilateral sensorineural hearing loss of sudden onset during an aeroplane flight, which completely resolved during a roller coaster ride at Alton Towers theme park. A review of the literature concerning sudden idiopathic sensorineural hearing loss and spontaneous resolution are discussed. Initially, pure-tone audiometry showed a profound sensorineural hearing loss in the right ear and mild sensorineural hearing loss in the left ear (of note, the hearing was normal p...

  13. Study of Stress and Strain Distributions of First Pass Conventional Spinning Under Different Roller-trace

    Institute of Scientific and Technical Information of China (English)

    2002-01-01

    Based on simplified axisymmetrical forming model, a elasto-plastic FEM simulation system of multi-pass conventional spinning is developed. Taking the typical draw-spinning as the study object, and establishing reasonable mechanics model, research on the first pass of spinning process is carried out with FEM system developed. The distributions of the stress and strain are obtained by three types of roller-trace curves: straight line, involute curves and quadratic curves. The results are as follows: (1) The v...

  14. Development of the Roller Pump for Use in the Cardiopulmonary Bypass Circuit

    OpenAIRE

    Cooley, Denton A.

    1987-01-01

    In 1937, John Gibbon proposed his concept of extracorporeal circulation as an aid to cardiac surgery. Subsequently, a number of different types of pumps were tried in the extracorporeal circuit. Today, the pump used most often is a positive displacement twin roller pump, originally patented by Porter and Bradley in 1855. The rotary pump has undergone some minor modifications prior to its use in clinical cardiopulmonary bypass. Cardiovascular surgeons owe much to Porter and Bradley for an inve...

  15. On Calculation Methods and Results for Straight Cylindrical Roller Bearing Deflection, Stiffness, and Stress

    Science.gov (United States)

    Krantz, Timothy L.

    2011-01-01

    The purpose of this study was to assess some calculation methods for quantifying the relationships of bearing geometry, material properties, load, deflection, stiffness, and stress. The scope of the work was limited to two-dimensional modeling of straight cylindrical roller bearings. Preparations for studies of dynamic response of bearings with damaged surfaces motivated this work. Studies were selected to exercise and build confidence in the numerical tools. Three calculation methods were used in this work. Two of the methods were numerical solutions of the Hertz contact approach. The third method used was a combined finite element surface integral method. Example calculations were done for a single roller loaded between an inner and outer raceway for code verification. Next, a bearing with 13 rollers and all-steel construction was used as an example to do additional code verification, including an assessment of the leading order of accuracy of the finite element and surface integral method. Results from that study show that the method is at least first-order accurate. Those results also show that the contact grid refinement has a more significant influence on precision as compared to the finite element grid refinement. To explore the influence of material properties, the 13-roller bearing was modeled as made from Nitinol 60, a material with very different properties from steel and showing some potential for bearing applications. The codes were exercised to compare contact areas and stress levels for steel and Nitinol 60 bearings operating at equivalent power density. As a step toward modeling the dynamic response of bearings having surface damage, static analyses were completed to simulate a bearing with a spall or similar damage.

  16. Rereading "The Jack-Roller:" Hidden Histories in Sociology and Social Work

    Science.gov (United States)

    Shaw, Ian

    2009-01-01

    I revisit one of the iconic Chicago School studies, Clifford Shaw's "The Jack-Roller". A naive reading of Shaw's book leaves the reader with a sense of having been inducted into a melange of what we now know as "sociology" and "social work," but which to Shaw seems a coherent stance. I suggest that this is close to the heart of how things were,…

  17. Neuromuscular Responses of Elite Skaters During Different Roller Figure Skating Jumps

    Directory of Open Access Journals (Sweden)

    Pantoja Patrícia Dias

    2014-07-01

    Full Text Available This study aimed to describe the neuromuscular activity of elite athletes who performed various roller figure skating jumps, to determine whether the muscle activation is greater during jumps with more rotations and in which phase the muscles are more active. This study also aimed to analyze if there is any difference in the muscle activity pattern between female and male skaters. Four elite skaters were evaluated, and each participated in two experimental sessions. During the first session, anthropometric data were collected, and the consent forms were signed. For the second session, neuromuscular data were collected during jumps, which were performed with skates at a rink. The following four roller figure skating jumps were evaluated: single Axel, double Axel, double Mapes and triple Mapes. The neuromuscular activity of the following seven muscles was obtained with an electromyograph which was fixed to the waist of each skater with a strap: biceps femoris, lateral gastrocnemius, tibialis anterior, rectus femoris, vastus lateralis, vastus medialis and gluteus maximus. The signal was transmitted wirelessly to a laptop. During the roller figure skating jumps, the lateral gastrocnemius, rectus femoris, vastus lateralis, biceps femoris and gluteus maximus, showed more activation during the jumps with more rotations, and the activation mainly occurred during the propulsion and flight phases. Female skaters demonstrated higher muscle activities in tibialis anterior, vastus lateralis, vastus medialis and gluteus maximus during the landing phase of the triple Mapes, when compared to their male counterparts. The results obtained in this study should be considered when planning training programs with specific exercises that closely resemble the roller figure skating jumps. This may be important for the success of elite skaters in competitions.

  18. Comparison of hole surface finishing processes with roller burnishing method applied in copper materials

    OpenAIRE

    Adnan AKKURT; Kurt, Abdullah; Ahmet ÖZDEMİR; ŞEKER, Ulvi

    2014-01-01

    Surface finishing processes such as drilling, turning, reaming, grinding, honing and roller burnishing etc. are widely used in manufacturing as hole surface finishing process. In addition to the characteristics of hole such as the surface roughness, the surface hardness and the wear resistance, the circularity and cylindricality of hole are also effective on the performance of hole. In this paper, it is presented that different hole surface finishing processes were applied to the samples made...

  19. Roller and Centrifugal Pumps: A Retrospective Comparison of Bleeding Complications in Extracorporeal Membrane Oxygenation.

    Science.gov (United States)

    Halaweish, Ihab; Cole, Adam; Cooley, Elaine; Lynch, William R; Haft, Jonathan W

    2015-01-01

    Centrifugal pumps are increasingly used for extracorporeal membrane oxygenation (ECMO) rather than roller pumps. However, shear forces induced by these types of continuousflow pumps are associated with acquired von Willebrand factor deficiency and bleeding complications. This study was undertaken to compare adverse bleeding complications with the use of centrifugal and roller pumps in patients on prolonged ECMO support. The records of all adult ECMO patients from June 2002 to 2013 were retrospectively reviewed using the University of Michigan Health System database and the Extracorporeal Life Support Organization registry, focusing on patients supported for at least 5 days. Ninety-five ECMO patients met criteria for inclusion (48 roller vs. 47 centrifugal pump). Indications included pulmonary (79%), cardiac (15%), and extracorporeal cardiopulmonary resuscitation (6%), without significant difference between the two groups. Despite lower heparin anticoagulation (10.9 vs. 13.7 IU/kg/hr) with centrifugal pumps, there was a higher incidence of nonsurgical bleeding (gastrointestinal, pulmonary, and neurological) in centrifugal pump patients (26.1 vs. 9.0 events/1,000 patient-days, p = 0.024). In conclusion, in our historical comparison, despite reduced anticoagulation, ECMO support using centrifugal pumps was associated with a higher incidence of nonsurgical bleeding. The mechanisms behind this are multifactorial and require further investigation.

  20. Intermittent stick-slip dynamics during the peeling of an adhesive tape from a roller.

    Science.gov (United States)

    Cortet, Pierre-Philippe; Dalbe, Marie-Julie; Guerra, Claudia; Cohen, Caroline; Ciccotti, Matteo; Santucci, Stéphane; Vanel, Loïc

    2013-02-01

    We study experimentally the fracture dynamics during the peeling at a constant velocity of a roller adhesive tape mounted on a freely rotating pulley. Thanks to a high speed camera, we measure, in an intermediate range of peeling velocities, high frequency oscillations between phases of slow and rapid propagation of the peeling fracture. This so-called stick-slip regime is well known as the consequence of a decreasing fracture energy of the adhesive in a certain range of peeling velocity coupled to the elasticity of the peeled tape. Simultaneously with stick slip, we observe low frequency oscillations of the adhesive roller angular velocity which are the consequence of a pendular instability of the roller submitted to the peeling force. The stick-slip dynamics is shown to become intermittent due to these slow pendular oscillations which produce a quasistatic oscillation of the peeling angle while keeping constant the peeling fracture velocity (averaged over each stick-slip cycle). The observed correlation between the mean peeling angle and the stick-slip amplitude questions the validity of the usually admitted independence with the peeling angle of the fracture energy of adhesives.

  1. 压丝辊的重新设计%Redesign of the contact rollers

    Institute of Scientific and Technical Information of China (English)

    冯岩; 赵新华

    2013-01-01

    通过对化纤长丝高速卷绕机压丝辊传动方式的深入研究,根据压丝辊主动驱动的发展趋势,结合电动机的工作原理,将卷绕头中的压丝辊做成电动机的转子,取代压丝辊加装的额外电机,从而使卷绕机的机械构造更加紧凑,减少占用空间.%Through analyzing the contact roller drive of high speed winding machine for synthetic filament, and combining the motors principle of work with the trend of development of initiative drive of contact roller in high-speed winding machine, makes the contact roller to motor rotor and takes the place of the additional motor. In order to make the winding mechanism be more compact, the use of room is reduced.

  2. Forces and mechanical energy fluctuations during diagonal stride roller skiing; running on wheels?

    Science.gov (United States)

    Kehler, Alyse L; Hajkova, Eliska; Holmberg, Hans-Christer; Kram, Rodger

    2014-11-01

    Mechanical energy can be conserved during terrestrial locomotion in two ways: the inverted pendulum mechanism for walking and the spring-mass mechanism for running. Here, we investigated whether diagonal stride cross-country roller skiing (DIA) utilizes similar mechanisms. Based on previous studies, we hypothesized that running and DIA would share similar phase relationships and magnitudes of kinetic energy (KE), and gravitational potential energy (GPE) fluctuations, indicating elastic energy storage and return, as if roller skiing is like 'running on wheels'. Experienced skiers (N=9) walked and ran at 1.25 and 3 m s(-1), respectively, and roller skied with DIA at both speeds on a level dual-belt treadmill that recorded perpendicular and parallel forces. We calculated the KE and GPE of the center of mass from the force recordings. As expected, the KE and GPE fluctuated with an out-of-phase pattern during walking and an in-phase pattern during running. Unlike walking, during DIA, the KE and GPE fluctuations were in phase, as they are in running. However, during the glide phase, KE was dissipated as frictional heat and could not be stored elastically in the tendons, as in running. Elastic energy storage and return epitomize running and thus we reject our hypothesis. Diagonal stride cross-country skiing is a biomechanically unique movement that only superficially resembles walking or running.

  3. Clinical use of centrifugal pumps and the roller pump in open heart surgery: a comparative evaluation.

    Science.gov (United States)

    Yoshikai, M; Hamada, M; Takarabe, K; Okazaki, Y; Ito, T

    1996-06-01

    Centrifugal pumps have been used widely as the main pump in open heart surgery to reduce damage to blood elements and to reduce the activation of the coagulation system. The purpose of this study was the evaluation and comparison of the effects of two types of centrifugal pumps and of one type of roller pump on blood elements, the coagulation system, complements, and immunoglobulins. Two types of centrifugal pumps (Lifestream; St. Jude Medical, Chelmsford, Massachusetts; and BP-80: Medtronic, BioMedicus, Inc., Eden Prairie, Minnesota, U.S.A.) and one roller pump (Mera Co.) were used separately as the main pump for cardiopulmonary bypass (CPB) in 29 patients. Platelet counts, lactate dehydrogenase, antithrombin III, thrombin-antithrombin complex (TAT), complements (C3, C4, and CH50) and immunoglobulins G, A, and M values were measured before and after CPB and compared. Values, except those for TAT, showed no significant difference among the three groups. The TAT values increased less in each of the centrifugal pump groups than in the roller pump group. This finding suggests that thrombin synthesis might be suppressed by the use of a centrifugal pump.

  4. Failure Analysis of Scraping Roller%刮胶辊的失效分析

    Institute of Scientific and Technical Information of China (English)

    洪永昌; 韩波

    2013-01-01

    利用金相显微镜和扫描电镜及能谱仪对磨损的刮胶辊组织和表面形貌进行了观察和分析,探讨了刮胶辊的失效原因。结果表明,镀Cr层成分不均匀,并存在少量氧化物夹杂、空洞和显微裂纹,是刮胶辊因磨损而过早产生失效的主要原因。提出了经改进的刮胶辊生产工艺。%The microstructure and surface morphology of worn scraping roller were observed and analyzed by OM , SEM and EDS , and its failure reasons were discussed .The results show that premature failure of the scraping roller due to wear is primarily caused by uneven composition , a small amount of oxide inclusions , voids and microcracks present in the chromium coating .An improved production process was suggested for the scraping roller .

  5. Tracking Porters

    DEFF Research Database (Denmark)

    Bruun, Maja Hojer; Krause-Jensen, Jakob; Saltofte, Margit

    2015-01-01

    Anthropology attempts to gain insight into people's experiential life-worlds through long-term fieldwork. The quality of anthropological knowledge production, however, does not depend solely on the duration of the stay in the field, but also on a particular way of seeing social situations. The an...... the students followed the work of a group of porters. Drawing on anthropological concepts and research strategies the students gained crucial insights about the potential effects of using tracking technologies in the hospital....

  6. Finite Element Analysis of Residual Stress in Ti-6Al-4V Alloy Plate Induced by Deep Rolling Process under Complex Roller Path

    Directory of Open Access Journals (Sweden)

    J. J. Liou

    2014-01-01

    Full Text Available The kinematics of the deep rolling tool, contact stress, and induced residual stress in the near-surface material of a flat Ti-6Al-4V alloy plate are numerically investigated. The deep rolling tool is under multiaxis nonlinear motion in the process. Unlike available deep rolling simulations in the open literature, the roller motion investigated in this study includes penetrative and slightly translational motions. A three-dimensional finite element model with dynamic explicit technique is developed to simulate the instantaneous complex roller motions during the deep rolling process. The initial motion of the rollers followed by the penetration motion to apply the load and perform the deep rolling process, the load releasing, and material recovery steps is sequentially simulated. This model is able to capture the transient characteristics of the kinematics on the roller and contacts between the roller and the plate due to variations of roller motion. The predictions show that the magnitude of roller reaction force in the penetration direction starts to decrease with time when the roller motion changes to the deep rolling step and the residual stress distributions in the near-surface material after the material recovery step varies considerably along the roller path.

  7. Tracking telecommuting

    Energy Technology Data Exchange (ETDEWEB)

    Stastny, P.

    2007-03-15

    Many employees are now choosing to work from home using laptops and telephones. Employers in the oil and gas industry are now reaping a number of benefits from their telecommuting employees, including increased productivity; higher levels of employee satisfaction, and less absenteeism. Providing a telecommunication option can prove to be advantageous for employers wishing to hire or retain employees. Telecommuting may also help to reduce greenhouse gas (GHG) emissions. This article provided details of Teletrips Inc., a company that aids in the production of corporate social responsibility reports. Teletrips provides reports that document employee savings in time, vehicle depreciation maintenance, and gasoline costs. Teletrips currently tracks 12 companies in Calgary, and plans to grow through the development of key technology partnerships. The company is also working with the federal government to provide their clients with emission trading credits, and has forged a memorandum of understanding with the British Columbia government for tracking emissions. Calgary now openly supports telecommuting and is encouraging businesses in the city to adopt telecommuting on a larger scale. It was concluded that the expanding needs for road infrastructure and the energy used by cars to move workers in and out of the city are a massive burden to the city's tax base. 1 fig.

  8. INNER TRACKING

    CERN Multimedia

    P. Sharp

    The CMS Inner Tracking Detector continues to make good progress. The Objective for 2006 was to complete all of the CMS Tracker sub-detectors and to start the integration of the sub-detectors into the Tracker Support Tube (TST). The Objective for 2007 is to deliver to CMS a completed, installed, commissioned and calibrated Tracking System (Silicon Strip and Pixels) aligned to < 100µ in April 2008 ready for the first physics collisions at LHC. In November 2006 all of the sub-detectors had been delivered to the Tracker Integration facility (TIF) at CERN and the tests and QA procedures to be carried out on each sub-detector before integration had been established. In December 2006, TIB/TID+ was integrated into TOB+, TIB/TID- was being prepared for integration, and TEC+ was undergoing tests at the final tracker operating temperature (-100 C) in the Lyon cold room. In February 2007, TIB/TID- has been integrated into TOB-, and the installation of the pixel support tube and the services for TI...

  9. Experimental Validation of a Compound Control Scheme for a Two-Axis Inertially Stabilized Platform with Multi-Sensors in an Unmanned Helicopter-Based Airborne Power Line Inspection System

    Directory of Open Access Journals (Sweden)

    Xiangyang Zhou

    2016-03-01

    Full Text Available A compound control scheme is proposed to achieve high control performance for a two-axis inertially stabilized platform (ISP with multi-sensors applied to an unmanned helicopter (UH-based airborne power line inspection (APLI system. Compared with the traditional two closed-loop control scheme that is composed of a high-bandwidth rate loop and a lower bandwidth position loop, a new current loop inside rate loop is particularly designed to suppress the influences of voltage fluctuation from power supply and motor back electromotive force (BEMF on control precision. In this way, the stabilization accuracy of the ISP is greatly improved. The rate loop, which is the middle one, is used to improve sensor’s stability precision through compensating for various disturbances. To ensure the pointing accuracy of the line of sight (LOS of multi-sensors, the position loop is designed to be the outer one and acts as the main feedback path, by which the accurate pointing angular position is achieved. To validate the scheme, a series of experiments were carried out. The results show that the proposed compound control scheme can achieve reliable control precision and satisfy the requirements of real APLI tasks.

  10. Elite cross-country skiers do not reach their running VO2max during roller ski skating.

    Science.gov (United States)

    Losnegard, T; Hallén, J

    2014-08-01

    Cross-country skiers' VO2max is often measured during treadmill running. However, VO2max during treadmill skiing with the diagonal stride technique is higher, whereas it is lower during double poling, another classical style technique. How these values compare to VO2max during ski skating in elite cross country skiers is not known. Therefore, this study compared VO2max during treadmill uphill running and treadmill roller ski skating. Twenty-two males (21±2 years, 182±6 cm, 77±7 kg, VO2max running; 72.4±4.4 mL·kg-1·min-1) elite cross-country skiers and biathlon athletes underwent testing in both running and roller ski skating before (May) and at the end (October) of the preseason training. From May to October VO2max increased during running (3.1±4.5%, P=0.003, Effect size; ES=0.44, small) but not during roller ski skating (1.8±5.6%, P=0.13, ES=0.24, small). In May the subjects' VO2max during running was 1.7±4.7% higher compared to during roller ski skating (P=0.08, ES=0.24, small) while in October this difference was 3.0±5.0 % (PVO2max during roller ski skating than during running and this relationship does not change during the pre-season training period.

  11. Effects of design parameters on carrying capacity of a double-row tapered roller slewing bearing used in wind turbine

    Directory of Open Access Journals (Sweden)

    Yunfeng Li

    2016-07-01

    Full Text Available Mechanical model with detailed design parameters of a rotor slewing bearing with the structure type of double-row tapered roller for supporting the rotor of the wind turbine was presented. The internal geometrical relationships of the rotor slewing bearing were established in the Cartesian coordinate system. The elastic contact deformations between each tapered roller and the raceways were expressed through the geometrical transformation. The mechanical model was established using the equilibrium relations in the rotor slewing bearing. The safety factor and the fatigue life which represents, respectively, the ability of resisting the rolling contact plastic deformation failure and the rolling contact fatigue failure of the rotor slewing bearing were obtained based on the solution of the mechanical model. Effects of the detailed design parameters such as axial clearance, contact angle, and roller semi-cone angle on the carrying capacity of the rotor slewing bearing were analyzed. The results show that right amount of small negative axial clearance, increase in contact angle, and decrease in roller semi-cone angle are advantageous for enhancing the carrying capacity of the rotor slewing bearing. This provides the basis for the reasonable value selection of the design parameters of the double-row tapered roller slewing bearing for supporting the rotor of the wind turbine.

  12. A new computational fluid dynamics method for in-depth investigation of flow dynamics in roller pump systems.

    Science.gov (United States)

    Zhou, Xiaoming; Liang, Xin M; Zhao, Gang; Su, Youchao; Wang, Yang

    2014-07-01

    Roller pumps are commonly used in circulatory assist devices to deliver blood, but the inherent high mechanical stresses (especially wall shear stress) may cause considerable damage to cells. Conventional experimental approaches to evaluate and reduce device-induced cell damage require considerable effort and resources. In this work, we describe the use of a new computational fluid dynamics method to more effectively study roller pump systems. A generalized parametric model for the fluid field in a typical roller pump system is presented first, and analytical formulations of the moving boundary are then derived. Based on the model and formulations, the dynamic geometry and mesh of the fluid field can be updated automatically according to the time-dependent roller positions. The described method successfully simulated the pulsing flow generated by the pump, offering a convenient way to visualize the inherent flow pattern and to assess shear-induced cell damage. Moreover, the highly reconfigurable model and the semiautomated simulation process extend the usefulness of the presented method to a wider range of applications. Comparison studies were conducted, and valuable indications about the detailed effects of structural parameters and operational conditions on the produced wall shear stress were obtained. Given the good consistency between the simulated results and the existing experimental data, the presented method displays promising potential to more effectively guide the development of improved roller pump systems which produce less mechanical damage to cells.

  13. Application of LCD-SVD Technique and CRO-SVM Method to Fault Diagnosis for Roller Bearing

    Directory of Open Access Journals (Sweden)

    Songrong Luo

    2015-01-01

    Full Text Available Targeting the nonlinear and nonstationary characteristics of vibration signal from fault roller bearing and scarcity of fault samples, a novel method is presented and applied to roller bearing fault diagnosis in this paper. Firstly, the nonlinear and nonstationary vibration signal produced by local faults of roller bearing is decomposed into intrinsic scale components (ISCs by using local characteristic-scale decomposition (LCD method and initial feature vector matrices are obtained. Secondly, fault feature values are extracted by singular value decomposition (SVD techniques to obtain singular values, while avoiding the selection of reconstruction parameters. Thirdly, a support vector machine (SVM classifier based on Chemical Reaction Optimization (CRO algorithm, called CRO-SVM method, is designed for classification of fault location. Lastly, the proposed method is validated by two experimental datasets. Experimental results show that the proposed method based LCD-SVD technique and CRO-SVM method have higher classification accuracy and shorter cost time than the comparative methods.

  14. The use of near-infrared and microwave resonance sensing to monitor a continuous roller compaction process.

    Science.gov (United States)

    Austin, John; Gupta, Anshu; McDonnell, Ryan; Reklaitis, Gintaras V; Harris, Michael T

    2013-06-01

    Roller compaction is commonly used in the pharmaceutical and nutraceutical industries to increase and narrow the size distribution of a particulate material, making it easier to process. Both the moisture content of the material and the density of the roller compacted ribbon affect the uniformity and physical properties of the resultant granules. Without process analytical technologies, these parameters cannot be determined on-line or in real time. In this study, the more commonly used near-infrared (NIR) spectroscopy was compared and contrasted with microwave resonance for the determination of roller-compacted ribbons' envelope density and moisture content. Results indicate that microwave resonance can offer improved accuracy, robustness, and ease-of-use compared with NIR spectroscopy for these property measurements. Copyright © 2013 Wiley Periodicals, Inc.

  15. Cadenas de rodillos. Tendencias de desarrollo y dimensionales según normas ISO. // Trends of roller chain and dimensional series according to ISO standards.

    Directory of Open Access Journals (Sweden)

    M. E. García Domínguez

    2007-05-01

    Full Text Available El artículo es una compilación de resultados derivados de un estudio del desarrollo de la transmisión por cadena de rodillosque permite brindar información relevante sobre la tendencia del mercado internacional, innovaciones recientes en lascadenas de rodillos y las diferencias dimensionales que caracterizan las series geométricas de las cadenas ISO-A e ISO-Bsegún la norma ISO 606:2004.Palabras claves: Cadena de rodillos, ISO 606, dimensiones de cadenas de rodillos.______________________________________________________________________________Abstract:The paper is a compilation of some results associated with the development of roller chain transmissions and outstanding informationin relations with the roller chain market trend, recent innovations and dimensional differences of ISO-A and ISO-B roller chain seriesaccording to ISO Standard 606:2004.Key Words: roller chain, ISO 606, roller chain dimension.

  16. Analysis of Hearth Roller Pickup Occurred Inside Annealing Furnace and Countermeasures%带钢热处理炉辊结瘤分析及对策

    Institute of Scientific and Technical Information of China (English)

    付建辉; 杨柏松

    2013-01-01

    阐述了带钢热处理退火炉炉辊结瘤的原因,分析认为防止带钢打滑和涂层是解决炉辊结瘤的有效手段,同时针对高强板MnO结瘤进行了论证,并提出了DPC74涂层是防止该种结瘤的一种有效手段.%The reasons of hearth roller pickup occurred inside annealing furnace are described.It is thought that avoiding strip slip from the hearth roller and coating for hearth roller are the effective measures to prevent hearth roller pickup.MnO hearth roller pickup of high strength plate is demonstrated,and it is pointed that the coating DPC74 is an effective way to prevent this kind of pickup from occurring.

  17. A 23.2:1 ratio, 300-watt, 26 N-m output torque, planetary roller-gear robotic transmission: Design and evaluation

    Science.gov (United States)

    Newman, Wyatt S.; Anderson, William J.; Shipitalo, William; Rohn, Douglas

    1992-01-01

    The design philosophy and measurements performed on a new roller-gear transmission prototype for a robotic manipulator are described. The design incorporates smooth rollers in a planetary configuration integrated with conventional toothed gears. The rollers were designed to handle low torque with low backlash and friction while the complementary gears support higher torques and prevent accumulated creep or slip of the rollers. The introduction of gears with finite numbers of teeth to function in parallel with the rollers imposes severe limits on available designs. Solutions for two-planet row designs are discussed. A two-planet row, four-planet design was conceived, fabricated, and tested. Detailed calculations of cluster geometry, gear stresses, and gear geometry are given. Measurement data reported here include transmission linearity, static and dynamic friction, inertia, backlash, stiffness, and forward and reverse efficiency. Initial test results are reported describing performance of the transmission in a servomechanism with torque feedback.

  18. Usefulness of extracorporeal membrane oxygenation using double roller pumps in a low body weight newborn: A novel strategy for mechanical circulatory support in an infant

    Directory of Open Access Journals (Sweden)

    Keisuke Nakanishi

    2016-01-01

    Full Text Available Extracorporeal membrane oxygenation (ECMO with a centrifugal pump requires a certain flow rate; therefore, its application for low body weight infants is frequently accompanied by oxygenator membrane malfunction and/or inadequate perfusion. To prevent low-flow associated complications, we report a case in which a novel system of dual roller pumps was used. A baby girl with a body mass index 0.25 m 2 , who experienced difficulty weaning from cardiopulmonary bypass after a Norwood-like operation, required an ECMO. Concerns for the tube lifespan reduction due to roller pump friction led to the use of a double roller pump circulation. The termination of ECMO during tube exchange is not needed, because circulation is maintained by another roller pump. The novel strategy of ECMO with double roller pumps will allow low perfusion rate to provide adequate circulatory support for low body weight patients.

  19. HIGH-SPEED FLOW EROSION ON A NEW ROLLER COMPACTED CONCRETE DAM DURING CONSTRUCTION

    Institute of Scientific and Technical Information of China (English)

    WANG Xin; LUO Shao-ze; HU Ya-an; YUAN Qiang; WANG He-sheng; ZHAO Lan-hao

    2012-01-01

    A new roller compacted concrete dam of Fengman Hydropower Station is to be built in the toe of the old dam,which was identified as a dangerous dam.The new dam during construction would be influenced by the high-speed flow discharged from the old dam,which is an important problem to be considered for the first time in China,and which would affect the construction of the whole project.Therefore,a series of erosion experiments were conducted in this article.A high-speed flow erosion test apparatus was developed for the erosion experiments of the new dam materials.The maximum jet velocity goes up to 40 m/s and the section area of the nozzle is 0.0025 m2.In the process of experiments,the equipment shows a good performance.Erosive wear tests for two types of materials used in the new dam,a roller compacted concrete and a distorted concrete with four kinds of ages were carried out with the flow velocity in the range of 30 m/s-35 m/s.Erosion parameters and erosion laws for the two types of concretes with different ages were determined,and a general relationship between the erosion rate and the flow velocity is obtained as:N =cvP,with the velocity exponent P between 3.33 and 3.93.It is concluded that the erosion resistance of the distorted concrete is better than that of the roller compacted concrete and the mechanical properties of the concretes of over 14 d age are influenced slightly by the water impact.The test results might serve as a practical technique guide for the safety of this project during its construction in the flood season.

  20. Anaerobic threshold assessment through the ventilatory method during roller-ski skating testing: right or wrong?

    Science.gov (United States)

    Fabre, Nicolas; Bortolan, Lorenzo; Pellegrini, Barbara; Zerbini, Livio; Mourot, Laurent; Schena, Federico

    2012-02-01

    This study aimed at questioning the validity of the ventilatory method to determine the anaerobic threshold (respiratory compensation point [RCP]) during an incremental roller-ski skating test to exhaustion. Nine elite crosscountry skiers were evaluated. The skiers carried out an incremental roller-ski test on a treadmill with the V2 skating technique. Ventilatory parameters were continuously collected breath by breath, thanks to a portable gas exchange measurement system. Poling signal was obtained using instrumented ski poles. For each stage, ventilatory and poling signals were synchronized and averaged. The poor coefficient of interobserver reliability for the time at RCP confirmed the great difficulty felt by the 3 blinded reviewers for the RCP determination. Moreover, the reviewer agreed with the impossibility of determining RCP in 4 of the 9 skiers. There was no significant difference between breathing frequency (Bf) and poling frequency (Pf) during the last 8 stages. However, it seems that the differences observed during the first stages arose from the use of either a strictly 1:1 or a 1:2 Bf to Pf ratio when the exercise intensity was still moderate. So, even if there were significant differences between the frequencies, the Bf was strictly subordinate to the Pf during the entire test. In the same way, the normalized tidal volume and peak poling forces curves were superposable. These findings showed that when the upper body is mainly involved in the propulsion, the determinants of the ventilation are strictly dependent on the poling pattern during an incremental test to exhaustion. Thus, during roller-ski skating, the determination of RCP must be used cautiously because too much depending on mechanical factors.

  1. Serum ferritin and serum iron changes after cross-country and roller ski endurance races.

    Science.gov (United States)

    Pattini, A; Schena, F; Guidi, G C

    1990-01-01

    We have studied the variations induced in iron status parameters by four endurance races of different lengths. A comprehensive group of 48 healthy, non-iron deficient, endurance athletes were evaluated before and after four different cross-country and roller ski races: I = Skirollonga, roller ski race for individuals (n = 10), mean duration (MD) = 1 h 48 min; II = Marcialonga, cross-country ski race for individuals (n = 9) MD = 3 h 10 min; III = 12-h of Caldonazzo (Trento-Italy) roller ski relay race (n = 13) MD = 12 h; IV = 24-h of Pinzolo (Trento-Italy) cross-country ski relay race (n = 16) MD = 24 h. In the relays the MD includes both exercise and recovery times. Blood samples were taken before and after every race for the determination of the following haematological parameters: red blood count, haemoglobin, and packed cell volume, serum iron concentration [SI], serum ferritin concentration [FERR] and total iron binding capacity (TIBC). The results showed a constant significant increase of [FERR] after the races (+44.9% in I, +50.5% in II, +51.2% in III and +36.5% in IV, P less than 0.01) while [SI] increased only in the first two races (+28.2% in I and +19.7% in II, P less than 0.01) and showed a remarkable decrease in the longer races (-46.1% in III and -39% in IV, P less than 0.01). The TIBC increased in all the races (except II) to the same extent (range 10%-12%).(ABSTRACT TRUNCATED AT 250 WORDS)

  2. Design of a solar tracking interactive kiosk

    Science.gov (United States)

    Greene, Nathaniel R.; Brunskill, Jeffrey C.

    2017-01-01

    A two-axis solar tracker and its interactive kiosk were designed by an interdisciplinary team of students and faculty. The objective was to develop a publicly accessible kiosk that would facilitate the study of energy usage and production on campus. Tracking is accomplished by an open-loop algorithm, microcontroller, and ham radio rotator. Solar panel output is monitored in real time and displayed to the public with lights and digits that can be read by the casual passersby. While maximum power point tracking is the most accurate means of quantifying the output power of a photovoltaic panel, simplicity and design constraints dictated the use of short-circuit current as a proxy for power. A touchscreen display allows kiosk visitors to compare two solar panels, an automatic tracker that faces the sun, and an identical panel whose elevation and azimuth can be controlled with a virtual joystick. This project was a capstone experience for students in physics/engineering, computer science, and instructional technology. We discuss technical challenges and design choices, as well as the educational goals of the kiosk.

  3. DYNAMIC RESPONSE OF ROLLER GEAR INDEXING CAM SYSTEM CONSIDERING CLEARANCE AND MOTOR CHARACTERISTIC

    Institute of Scientific and Technical Information of China (English)

    2001-01-01

    The dynamic responses of roller gear indexing cam mechanism are investigated .With applying Lagarange equation and Gear method,motion equations of this mechanism including clearance,motor characteristic,torsion flexibility are developed and solved.The results show that clearance affects primarily the response on turret,and has little effects on the responses on rotary table.At the same time,the velocity fluctuation of motor shaft is not serious for the existence of inertia of reducer,and the high frequency of velocity fluctuation of camshaft is related with the torsion stiffness of shaft and the clearance between pairs.

  4. Improving the content uniformity of a low-dose tablet formulation through roller compaction optimization.

    Science.gov (United States)

    am Ende, Mary T; Moses, Sara K; Carella, Anthony J; Gadkari, Rashmi A; Graul, Timothy W; Otano, Angel L; Timpano, Robert J

    2007-01-01

    In this investigation, the potency distribution of a low-dose drug in a granulation was optimized through a two-part study using statistically designed experiments. The purpose of this investigation was to minimize the segregation potential by improving content uniformity across the granule particle size distribution, thereby improving content uniformity in the tablet. Initial operating parameters on the Gerteis 3-W-Polygran 250/100/3 Roller Compactor resulted in a U-shaped potency function (potency vs. granule particle size) with superpotent fines and large granules. The roller compaction optimization study was carried out in two parts. Study I used a full factorial design with roll force (RF) and average gap width (GW) as independent variables and Study II used a D-optimal response surface design with four factors: RF, GW, granulating sieve size (SS), and granulator speed (GS). The planned response variables for Study I were bypass weight % and potency of bypass. Response variables for Study II included mean granulation potency with % relative standard deviation (% RSD), granulation particle size, sieve cut potency % RSD, tablet potency with % RSD, compression force at 7 kP crushing strength, and friability of 7-kP tablets. A constraint on GW was determined in Study I by statistical analysis. Bypass and observations of ribbon splitting were minimized when GW was less than 2.6 mm. In Study II, granulation potency, granulation uniformity, and sieve cut uniformity were optimized when the SS was 0.8 mm. Higher RF during dry granulation produced better sieve cut uniformity and tablets with improved uniformity throughout the run, as measured by stratified tablet samples taken during compression and assayed for potency. The recommended optimum roller compaction and milling operating parameters that simultaneously met all constraints were RF = 9 kN, GW = 2.3 mm, SS = 0.8 mm, and GS = 50 rpm. These parameters became the operating parameter set points during a model

  5. VIRTUAL MODEL OF A ROLLER CONVEYOR INTEGRATED INTO A LOGISTIC FLOW

    Directory of Open Access Journals (Sweden)

    POPESCU Adrian

    2015-11-01

    Full Text Available In this article is presented, with the help of graphics, a logistic flow for palletizing and wrapping operations. The loaded pallets are transported by means of a roller conveyor. Creating the virtual model for the conveyer allows us to emphasize the compatibility elements between on the one hand the mechanical assemblies of the flow components and on the other hand the subassemblies of the conveyer structure. The paper has focused on the presentation of the conveyor specific assembly and how are placed the sensors on the mechanical structure of the conveyor. Finally, the main working phases are graphically presented within the flow, highlighting the loaded pallet positions in the flow.

  6. Macular hemorrhage after roller coaster riding in a single-eyed patient with congenital glaucoma

    Directory of Open Access Journals (Sweden)

    Dilek Guven

    Full Text Available ABSTRACT A 21-year-old female presented with a 4-day history of decreased vision in her only functional eye (right eye, OD. She had a history of multiple ocular surgeries in both eyes because of congenital glaucoma and had lost light perception in her left eye several years prior. Ophthalmological examination revealed 0.15 Snellen visual acuity, and fundoscopy revealed nearly total cupping and pallor of the optic disc and multiple retinal hemorrhagic foci in the macula in OD. Lesions spontaneously resolved over a few months. Gravitational forces during a roller coaster ride may have caused this macular hemorrhage.

  7. Development of the roller pump for use in the cardiopulmonary bypass circuit.

    Science.gov (United States)

    Cooley, D A

    1987-06-01

    In 1937, John Gibbon proposed his concept of extracorporeal circulation as an aid to cardiac surgery. Subsequently, a number of different types of pumps were tried in the extracorporeal circuit. Today, the pump used most often is a positive displacement twin roller pump, originally patented by Porter and Bradley in 1855. The rotary pump has undergone some minor modifications prior to its use in clinical cardiopulmonary bypass. Cardiovascular surgeons owe much to Porter and Bradley for an invention that has proved both efficient and effective for cardiopulmonary bypass and has allowed operations on an open heart in a relatively dry, bloodless field.

  8. Macular hemorrhage after roller coaster riding in a single-eyed patient with congenital glaucoma.

    Science.gov (United States)

    Guven, Dilek; Acar, Zeynep; Demir, Mehmet; Sendul, Yekta; Demir, Atilla Gokce; Ergen, Erdem

    2016-01-01

    A 21-year-old female presented with a 4-day history of decreased vision in her only functional eye (right eye, OD). She had a history of multiple ocular surgeries in both eyes because of congenital glaucoma and had lost light perception in her left eye several years prior. Ophthalmological examination revealed 0.15 Snellen visual acuity, and fundoscopy revealed nearly total cupping and pallor of the optic disc and multiple retinal hemorrhagic foci in the macula in OD. Lesions spontaneously resolved over a few months. Gravitational forces during a roller coaster ride may have caused this macular hemorrhage.

  9. INNER TRACKING

    CERN Multimedia

    P. Sharp

    The CMS Inner Tracking Detector continues to make good progress. The successful commissioning of ~ 25% of the Silicon Strip Tracker was completed in the Tracker Integration Facility (TIF) at CERN in July 2007 and the Tracker has since been prepared for moving and installation into CMS at P5. The Tracker was ready to move on schedule in September 2007. The Installation of the Tracker cooling pipes and LV cables between Patch Panel 1 (PP1) on the inside the CMS magnet cryostat, and the cooling plants and power system racks on the balconies has been completed. The optical fibres from PP1 to the readout FEDs in the USC have been installed, together with the Tracker cable channels, in parallel with the installation of the EB/HB services. All of the Tracker Safety, Power, DCS and the VME Readout Systems have been installed at P5 and are being tested and commissioned with CMS. It is planned to install the Tracker into CMS before Christmas. The Tracker will then be connected to the pre-installed services on Y...

  10. INNER TRACKING

    CERN Multimedia

    P. Sharp

    The CMS Inner Tracking Detector continues to make good progress. The successful commissioning of ~ 25% of the Silicon Strip Tracker was completed in the Tracker Integration Facility (TIF) at CERN on 18 July 2007 and the Tracker has since been prepared for moving and installation into CMS at P5. The Tracker will be ready to move on schedule in September 2007. The Installation of the Tracker cooling pipes and LV cables between Patch Panel 1 (PP1) on the inside the CMS magnet cryostat, and the cooling plants and power system racks on the balconies has been completed. The optical fibres from PP1 to the readout FEDs in the USC will be installed in parallel with the installation of the EB/HB services, and will be completed in October. It is planned to install the Tracker into CMS at the end of October, after the completion of the installation of the EB/HB services. The Tracker will then be connected to the pre-installed services on YB0 and commissioned with CMS in December. The FPix and BPix continue to make ...

  11. Patient Treatment Tracking Chart

    Science.gov (United States)

    ... ZIP code here Hepatitis C Treatment Tracking Chart Patient Treatment Tracking Chart Patient Treatment Tracking Chart Sample Chart This chart is ... this website Submit Share this page Related Resource Patient Treatment Tutorial return to top CONNECT Veterans Crisis ...

  12. Characterization of the New GBT Azimuth Track and Pointing Model

    Science.gov (United States)

    Hunter, T. R.; Constantikes, K. T.; Ghigo, F.; Brandt, J.; Grider, R.

    2008-01-01

    Following the completion of the mechanical aspect of the azimuth track refurbishment project (described in the October 2007 Newsletter), it was necessary to character- ize the performance of the new track and implement a new pointing model prior to the resumption of scheduled operations. The Precision Telescope Control System (PTCS) team was responsible for this effort, which required significant planning and development beginning a year ago in January 2007. Although there was high confidence that the refurbishment would yield a flatter and more resilient track, the possibility of remaining low-level features spurred the team to develop a robust technique for measuring track features prior to the April 30 shutdown. To characterize the track, the centerpiece instrument is a pair of two-axis gas-damped capacitive-readout inclinometers mounted on the ends of the elevation axle. With the new track, both the large scale (tens of degrees) and small scale structure has been greatly reduced, with an rms of 0.94 arcseconds (equivalent to 5.7 thousandths of an inch at the track radius). A repeated measurement of the new track over the timescale of a week has shown the remaining features to be stable, but it will be monitored occasionally during the coming year. The nighttime blind pointing performance now shows a standard deviation of 3.4" in cross-elevation, 3.7" in elevation, and 2.0 mm in focus. These rms values are improved by about 1" in elevation and 1 mm in focus over the previous model when compared under the same conditions in fall 2006 and spring 2007.

  13. Development of the Asphalt Multi-Integrated Roller Field and Experimental Studies

    Directory of Open Access Journals (Sweden)

    Abd El Halim Omar Abd El Halim

    2015-01-01

    Full Text Available Asphalt pavements have been compacted using steel drum rollers for a century. However, the problems that are observed today on these pavements are universal with no solution in sight. Intensive research work has been invested to identify the mechanisms that cause these problems. A recent development was the introduction of SuperPave mix design, GP asphalt cements, and the use of reinforcing elements ranging from polymer to steel bars. Yet it seems that none of these solutions have succeeded in eliminating any of the old problems. The pavements suffer from serious distresses regardless of the geographic location of the pavements and its design, materials, traffic loads, and climate condition. This paper presents a new approach to deal with the problems facing the asphalt pavements. While the research efforts to date concentrated on materials-related solutions, this paper identifies conventional compaction equipment as the cause of many problems observed on the pavements. The paper provides the development of the new Asphalt Multi-Integrated Roller, AMIR, and discusses new developments leading to a number of commercial field trials on several Ontario highways. The paper concludes that current compactors must be replaced with soft flat plates in order to achieve the required specifications for long term performance.

  14. Rolo destorroador após a semeadura do trigo Roller after wheat sowing

    Directory of Open Access Journals (Sweden)

    Luiz C. Garcia

    2008-06-01

    Full Text Available Teve-se o objetivo de verificar a influência do rolo destorroador utilizado após a semeadura do trigo, sobre palhada de milho, em duas unidades de produção agrícola. As variáveis analisadas foram: população de plantas 15 dias após a emergência, população de plantas com espigas, grãos por espiga, massa de 1.000 grãos, produtividade e viabilidade econômica da operação. A significativa elevação da população de plantas emergidas com o emprego do rolo destorroador não refletiu nos componentes de produção. Portanto, não se recomenda sua utilização nas condições experimentais.This experiment was carried out to verify the influence of a roller after wheat sowing under corn stover, in two farming areas. The variables studied were: plant population 15 days after seedling, population with cobs, grains per cob, 1000 seed weight, yield and the economic viability of the operation. The significant increase of emerged plants after the usage of a roller didn't reflect in the yield components. Therefore it's not recommended in experimental conditions.

  15. Presenting an Appropriate Neural Network for Optimal Mix Design of Roller Compacted Concrete Dams

    Directory of Open Access Journals (Sweden)

    Taha Mehmannavaz

    2014-03-01

    Full Text Available In general, one of the main targets to achieve the optimal mix design of concrete dams is to reduce the amount of cement, heat of hydration, increasing the size of aggregate (coarse and reduced the permeability. Thus, one of the methods which is used in construction of concrete and soil dams as a suitable replacement is construction of dams in roller compacted concrete method. Spending fewer budgets, using road building machinery, short time of construction and continuation of construction all are the specifications of this construction method, which have caused priority of these two methods and finally this method has been known as a suitable replacement for constructing dams in different parts of the world. On the other hand, expansion of the materials used in this type of concrete, complexity of its mix design, effect of different parameters on its mix design and also finding relations between different parameters of its mix design have necessitated the presentation of a model for roller compacted concretemix design. Artificial neural networks are one of the modeling methods which have shown very high power for adjustment to engineering problems. A kind of these networks, called Multi-Layer Perceptron (MLP neural networks, was used as the main core of modeling in this study along with error-back propagation training algorithm, which is mostly applied in modeling mapping behaviors.

  16. Performance of integrated systems of automated roller shade systems and daylight responsive dimming systems

    Energy Technology Data Exchange (ETDEWEB)

    Park, Byoung-Chul; Choi, An-Seop; Jeong, Jae-Weon [Department of Architectural Engineering, Sejong University, Kunja-Dong, Kwangjin-Gu, Seoul (Korea, Republic of); Lee, Eleanor S. [Building Technologies Department, Lawrence Berkeley National Laboratory, Berkeley, CA (United States)

    2011-03-15

    Daylight responsive dimming systems have been used in few buildings to date because they require improvements to improve reliability. The key underlying factor contributing to poor performance is the variability of the ratio of the photosensor signal to daylight workplane illuminance in accordance with sun position, sky condition, and fenestration condition. Therefore, this paper describes the integrated systems between automated roller shade systems and daylight responsive dimming systems with an improved closed-loop proportional control algorithm, and the relative performance of the integrated systems and single systems. The concept of the improved closed-loop proportional control algorithm for the integrated systems is to predict the varying correlation of photosensor signal to daylight workplane illuminance according to roller shade height and sky conditions for improvement of the system accuracy. In this study, the performance of the integrated systems with two improved closed-loop proportional control algorithms was compared with that of the current (modified) closed-loop proportional control algorithm. In the results, the average maintenance percentage and the average discrepancies of the target illuminance, as well as the average time under 90% of target illuminance for the integrated systems significantly improved in comparison with the current closed-loop proportional control algorithm for daylight responsive dimming systems as a single system. (author)

  17. Performance of Integrated Systems of Automated Roller Shade Systems and Daylight Responsive Dimming Systems

    Energy Technology Data Exchange (ETDEWEB)

    Park, Byoung-Chul; Choi, An-Seop; Jeong, Jae-Weon; Lee, Eleanor S.

    2010-07-08

    Daylight responsive dimming systems have been used in few buildings to date because they require improvements to improve reliability. The key underlying factor contributing to poor performance is the variability of the ratio of the photosensor signal to daylight workplane illuminance in accordance with sun position, sky condition, and fenestration condition. Therefore, this paper describes the integrated systems between automated roller shade systems and daylight responsive dimming systems with an improved closed-loop proportional control algorithm, and the relative performance of the integrated systems and single systems. The concept of the improved closed-loop proportional control algorithm for the integrated systems is to predict the varying correlation of photosensor signal to daylight workplane illuminance according to roller shade height and sky conditions for improvement of the system accuracy. In this study, the performance of the integrated systems with two improved closed-loop proportional control algorithms was compared with that of the current (modified) closed-loop proportional control algorithm. In the results, the average maintenance percentage and the average discrepancies of the target illuminance, as well as the average time under 90percent of target illuminance for the integrated systems significantly improved in comparison with the current closed-loop proportional control algorithm for daylight responsive dimming systems as a single system.

  18. A Sparsity-Promoted Decomposition for Compressed Fault Diagnosis of Roller Bearings

    Science.gov (United States)

    Wang, Huaqing; Ke, Yanliang; Song, Liuyang; Tang, Gang; Chen, Peng

    2016-01-01

    The traditional approaches for condition monitoring of roller bearings are almost always achieved under Shannon sampling theorem conditions, leading to a big-data problem. The compressed sensing (CS) theory provides a new solution to the big-data problem. However, the vibration signals are insufficiently sparse and it is difficult to achieve sparsity using the conventional techniques, which impedes the application of CS theory. Therefore, it is of great significance to promote the sparsity when applying the CS theory to fault diagnosis of roller bearings. To increase the sparsity of vibration signals, a sparsity-promoted method called the tunable Q-factor wavelet transform based on decomposing the analyzed signals into transient impact components and high oscillation components is utilized in this work. The former become sparser than the raw signals with noise eliminated, whereas the latter include noise. Thus, the decomposed transient impact components replace the original signals for analysis. The CS theory is applied to extract the fault features without complete reconstruction, which means that the reconstruction can be completed when the components with interested frequencies are detected and the fault diagnosis can be achieved during the reconstruction procedure. The application cases prove that the CS theory assisted by the tunable Q-factor wavelet transform can successfully extract the fault features from the compressed samples. PMID:27657063

  19. Simultaneous Comparison of Two Roller Compaction Techniques and Two Particle Size Analysis Methods.

    Science.gov (United States)

    Saarinen, Tuomas; Antikainen, Osmo; Yliruusi, Jouko

    2017-05-24

    A new dry granulation technique, gas-assisted roller compaction (GARC), was compared with conventional roller compaction (CRC) by manufacturing 34 granulation batches. The process variables studied were roll pressure, roll speed, and sieve size of the conical mill. The main quality attributes measured were granule size and flow characteristics. Within granulations also the real applicability of two particle size analysis techniques, sieve analysis (SA) and fast imaging technique (Flashsizer, FS), was tested. All granules obtained were acceptable. In general, the particle size of GARC granules was slightly larger than that of CRC granules. In addition, the GARC granules had better flowability. For example, the tablet weight variation of GARC granules was close to 2%, indicating good flowing and packing characteristics. The comparison of the two particle size analysis techniques showed that SA was more accurate in determining wide and bimodal size distributions while FS showed narrower and mono-modal distributions. However, both techniques gave good estimates for mean granule sizes. Overall, SA was a time-consuming but accurate technique that provided reliable information for the entire granule size distribution. By contrast, FS oversimplified the shape of the size distribution, but nevertheless yielded acceptable estimates for mean particle size. In general, FS was two to three orders of magnitude faster than SA.

  20. Modeling of Intermesh Schedule for Strong Heavy Plate Roller Straightener and Finite Element Method Modification

    Directory of Open Access Journals (Sweden)

    Meng Xu

    2016-01-01

    Full Text Available Regarding straightening unit as the research object, considered the different of roller spacing, a mathematical model of intermesh schedule suitable to the 2800 seven-roller strong heavy plate straightening machine was deduced by the geometric method. According to the mathematical model, the intermesh schedules of several specifications of plate were calculated, and the finite element model of straightening process was established in the finite element analysis software Abaqus. By analysing, it was found that those plates after straightening cannot meet the requirement of flatness, due to the existence of the work hardening. The bending deflection of the last straightening unit was modified and the new calculation formula of intermesh schedule was obtained. The values of the modified coefficients were determined by the finite element method. The intermesh schedules of other specifications of plate were calculated by the modified calculation formula and then verified it in Abaqus. The simulation results showed that those plates after straightening meet the requirement of flatness. So, the research results provide a theoretical basis for development of a new plate straightening machine and formulation of intermesh schedule.

  1. Lake Robertson hydroelectric project. Construction of a roller compacted concrete dam

    Energy Technology Data Exchange (ETDEWEB)

    Labelle, M.; Robitaille, F. [Hydro-Quebec, Montreal, PQ (Canada)

    1995-12-31

    Construction of the Lake Robertson hydroelectric project on Quebec`s Lower North Shore was discussed in detail. The dam and powerhouse, located on the HaHa River, consists of a 134 m long concrete gravity dam, and a 21 MW powerhouse with two 69 kV transmission lines and four substations. The climate, terrain, and geography of the region, all of them characterized as severe, and the logistics of construction of the dam and power lines, aggravated by the isolation and severe conditions at the site, were described. The roller compacted concrete design and construction were noted, and justification for a concrete dam over an earth-fill dam was provided. Economics, properties, and composition of the roller compacted concrete (RCC) were examined, and control test results for the RCC concrete were provided. The use of RCC for the Lake Robertson development was described as successful in terms of the quality, watertightness, and completion time. The experience gained by the participants will make it possible to offer RCC as an alternative on various other projects. 2 figs.

  2. Underdetermined Blind Source Separation with Variational Mode Decomposition for Compound Roller Bearing Fault Signals

    Directory of Open Access Journals (Sweden)

    Gang Tang

    2016-06-01

    Full Text Available In the condition monitoring of roller bearings, the measured signals are often compounded due to the unknown multi-vibration sources and complex transfer paths. Moreover, the sensors are limited in particular locations and numbers. Thus, this is a problem of underdetermined blind source separation for the vibration sources estimation, which makes it difficult to extract fault features exactly by ordinary methods in running tests. To improve the effectiveness of compound fault diagnosis in roller bearings, the present paper proposes a new method to solve the underdetermined problem and to extract fault features based on variational mode decomposition. In order to surmount the shortcomings of inadequate signals collected through limited sensors, a vibration signal is firstly decomposed into a number of band-limited intrinsic mode functions by variational mode decomposition. Then, the demodulated signal with the Hilbert transform of these multi-channel functions is used as the input matrix for independent component analysis. Finally, the compound faults are separated effectively by carrying out independent component analysis, which enables the fault features to be extracted more easily and identified more clearly. Experimental results validate the effectiveness of the proposed method in compound fault separation, and a comparison experiment shows that the proposed method has higher adaptability and practicability in separating strong noise signals than the commonly-used ensemble empirical mode decomposition method.

  3. Compressive Sensing of Roller Bearing Faults via Harmonic Detection from Under-Sampled Vibration Signals.

    Science.gov (United States)

    Tang, Gang; Hou, Wei; Wang, Huaqing; Luo, Ganggang; Ma, Jianwei

    2015-10-09

    The Shannon sampling principle requires substantial amounts of data to ensure the accuracy of on-line monitoring of roller bearing fault signals. Challenges are often encountered as a result of the cumbersome data monitoring, thus a novel method focused on compressed vibration signals for detecting roller bearing faults is developed in this study. Considering that harmonics often represent the fault characteristic frequencies in vibration signals, a compressive sensing frame of characteristic harmonics is proposed to detect bearing faults. A compressed vibration signal is first acquired from a sensing matrix with information preserved through a well-designed sampling strategy. A reconstruction process of the under-sampled vibration signal is then pursued as attempts are conducted to detect the characteristic harmonics from sparse measurements through a compressive matching pursuit strategy. In the proposed method bearing fault features depend on the existence of characteristic harmonics, as typically detected directly from compressed data far before reconstruction completion. The process of sampling and detection may then be performed simultaneously without complete recovery of the under-sampled signals. The effectiveness of the proposed method is validated by simulations and experiments.

  4. Fault Detection of Roller-Bearings Using Signal Processing and Optimization Algorithms

    Directory of Open Access Journals (Sweden)

    Dae-Ho Kwak

    2013-12-01

    Full Text Available This study presents a fault detection of roller bearings through signal processing and optimization techniques. After the occurrence of scratch-type defects on the inner race of bearings, variations of kurtosis values are investigated in terms of two different data processing techniques: minimum entropy deconvolution (MED, and the Teager-Kaiser Energy Operator (TKEO. MED and the TKEO are employed to qualitatively enhance the discrimination of defect-induced repeating peaks on bearing vibration data with measurement noise. Given the perspective of the execution sequence of MED and the TKEO, the study found that the kurtosis sensitivity towards a defect on bearings could be highly improved. Also, the vibration signal from both healthy and damaged bearings is decomposed into multiple intrinsic mode functions (IMFs, through empirical mode decomposition (EMD. The weight vectors of IMFs become design variables for a genetic algorithm (GA. The weights of each IMF can be optimized through the genetic algorithm, to enhance the sensitivity of kurtosis on damaged bearing signals. Experimental results show that the EMD-GA approach successfully improved the resolution of detectability between a roller bearing with defect, and an intact system.

  5. Automatic Identification of Subtechniques in Skating-Style Roller Skiing Using Inertial Sensors

    Directory of Open Access Journals (Sweden)

    Yoshihisa Sakurai

    2016-04-01

    Full Text Available This study aims to develop and validate an automated system for identifying skating-style cross-country subtechniques using inertial sensors. In the first experiment, the performance of a male cross-country skier was used to develop an automated identification system. In the second, eight male and seven female college cross-country skiers participated to validate the developed identification system. Each subject wore inertial sensors on both wrists and both roller skis, and a small video camera on a backpack. All subjects skied through a 3450 m roller ski course using a skating style at their maximum speed. The adopted subtechniques were identified by the automated method based on the data obtained from the sensors, as well as by visual observations from a video recording of the same ski run. The system correctly identified 6418 subtechniques from a total of 6768 cycles, which indicates an accuracy of 94.8%. The precisions of the automatic system for identifying the V1R, V1L, V2R, V2L, V2AR, and V2AL subtechniques were 87.6%, 87.0%, 97.5%, 97.8%, 92.1%, and 92.0%, respectively. Most incorrect identification cases occurred during a subtechnique identification that included a transition and turn event. Identification accuracy can be improved by separately identifying transition and turn events. This system could be used to evaluate each skier’s subtechniques in course conditions.

  6. A Two-Stage Compression Method for the Fault Detection of Roller Bearings

    Directory of Open Access Journals (Sweden)

    Huaqing Wang

    2016-01-01

    Full Text Available Data measurement of roller bearings condition monitoring is carried out based on the Shannon sampling theorem, resulting in massive amounts of redundant information, which will lead to a big-data problem increasing the difficulty of roller bearing fault diagnosis. To overcome the aforementioned shortcoming, a two-stage compressed fault detection strategy is proposed in this study. First, a sliding window is utilized to divide the original signals into several segments and a selected symptom parameter is employed to represent each segment, through which a symptom parameter wave can be obtained and the raw vibration signals are compressed to a certain level with the faulty information remaining. Second, a fault detection scheme based on the compressed sensing is applied to extract the fault features, which can compress the symptom parameter wave thoroughly with a random matrix called the measurement matrix. The experimental results validate the effectiveness of the proposed method and the comparison of the three selected symptom parameters is also presented in this paper.

  7. A Sparsity-Promoted Decomposition for Compressed Fault Diagnosis of Roller Bearings

    Directory of Open Access Journals (Sweden)

    Huaqing Wang

    2016-09-01

    Full Text Available The traditional approaches for condition monitoring of roller bearings are almost always achieved under Shannon sampling theorem conditions, leading to a big-data problem. The compressed sensing (CS theory provides a new solution to the big-data problem. However, the vibration signals are insufficiently sparse and it is difficult to achieve sparsity using the conventional techniques, which impedes the application of CS theory. Therefore, it is of great significance to promote the sparsity when applying the CS theory to fault diagnosis of roller bearings. To increase the sparsity of vibration signals, a sparsity-promoted method called the tunable Q-factor wavelet transform based on decomposing the analyzed signals into transient impact components and high oscillation components is utilized in this work. The former become sparser than the raw signals with noise eliminated, whereas the latter include noise. Thus, the decomposed transient impact components replace the original signals for analysis. The CS theory is applied to extract the fault features without complete reconstruction, which means that the reconstruction can be completed when the components with interested frequencies are detected and the fault diagnosis can be achieved during the reconstruction procedure. The application cases prove that the CS theory assisted by the tunable Q-factor wavelet transform can successfully extract the fault features from the compressed samples.

  8. Automatic Identification of Subtechniques in Skating-Style Roller Skiing Using Inertial Sensors.

    Science.gov (United States)

    Sakurai, Yoshihisa; Fujita, Zenya; Ishige, Yusuke

    2016-04-02

    This study aims to develop and validate an automated system for identifying skating-style cross-country subtechniques using inertial sensors. In the first experiment, the performance of a male cross-country skier was used to develop an automated identification system. In the second, eight male and seven female college cross-country skiers participated to validate the developed identification system. Each subject wore inertial sensors on both wrists and both roller skis, and a small video camera on a backpack. All subjects skied through a 3450 m roller ski course using a skating style at their maximum speed. The adopted subtechniques were identified by the automated method based on the data obtained from the sensors, as well as by visual observations from a video recording of the same ski run. The system correctly identified 6418 subtechniques from a total of 6768 cycles, which indicates an accuracy of 94.8%. The precisions of the automatic system for identifying the V1R, V1L, V2R, V2L, V2AR, and V2AL subtechniques were 87.6%, 87.0%, 97.5%, 97.8%, 92.1%, and 92.0%, respectively. Most incorrect identification cases occurred during a subtechnique identification that included a transition and turn event. Identification accuracy can be improved by separately identifying transition and turn events. This system could be used to evaluate each skier's subtechniques in course conditions.

  9. Influence of Surface-profile and Movement-path of Roller on Thickness Thinning during Multi-pass Deep Drawing Spinning

    Directory of Open Access Journals (Sweden)

    Xia Qinxiang

    2016-01-01

    Full Text Available Over thinning is a serious defect influencing the forming quality of spun workpiece during multi-pass deep drawing spinning. Surface-profile and movement-path of roller are the key factors influencing the thinning ratio of wall thickness of spun workpiece. The influence of surface-profile and movement-path of roller on thickness thinning were studied based on numerical simulation and experimental research, four groups of forming experiments were carried out under the combination of the different surface-profile of roller (R12 and R25-12 and movement-path of roller (spinning from the bottom of the blank and spinning from the middle of the blank. The results show that both the surface-profile and movement-path of roller have great influence on wall thickness thinning during multi-pass deep drawing spinning; and compared with the movement-path of roller, the influence of surface-profile of roller is more significant. The experimental results conform well to the simulation ones. It indicates that the FEA model established is reasonable and reliable.

  10. The influence of the residual stress in silicone tubes in the calibration methods of roller pumps used in cardiopulmonary bypass.

    Science.gov (United States)

    Vieira, Francisco Ubaldo; Vieira, Reinaldo Wilson; Antunes, Nilson; Petrucci, Orlando; de Oliveira, Pedro Paulo; Silveira Filho, Lindemberg da Mota; Vilarinho, Karlos Alexandre de Sousa; de Oliveira Severino, Elaine Soraya Barbosa

    2010-01-01

    The rotation of rollers in cardiopulmonary bypass pumps propels the blood through various devices to reach the patient. Very occlusive settings may squeeze red blood cells, whereas a nonocclusive setting may result in retrograde flow. Occlusion of roller pumps may be regulated either by measuring the drop rate or by dynamic calibration. This study evaluated the influence of silicone tubing residual stress found on pump regulation. Silicone tubes obtained from two different suppliers were used in 6-inch DeBakey roller pumps. The variations occurring over time in the measurements of drop rate, dynamic calibration, and tube residual stress were analyzed. Covariance analysis of the four linear regressions has shown a progressive and accentuated reduction in drop rate (p 0.56). This reduction in drop rate measurements may affect the regulation of the pumps before surgical procedures. One probable cause for this reduction is the residual stress found in the silicone tubes. Settings based on the dynamic calibration process tended to be repeated over time. Simple linear regression test (angular coefficient equals zero) has shown a p > 0.79 showing no interference of the silicone tubes residual stress on dynamic calibration, suggesting that one should use this method to calibrate roller pumps.

  11. Fire ants protect mealybugs against their natural enemies by utilizing the leaf shelters constructed by the leaf roller Sylepta derogata.

    Directory of Open Access Journals (Sweden)

    Aiming Zhou

    Full Text Available The importance of mutualism is receiving more attention in community ecology. In this study, the fire ant Solenopsis invicta was found to take advantage of the shelters constructed by the leaf roller Sylepta derogata to protect mealybugs (Phenacoccus solenopsis against their natural enemies. This protective effect of fire ant tending on the survival of mealybugs in shelters was observed when enemies and leaf rollers were simultaneously present. Specifically, fire ants moved the mealybugs inside the shelters produced by S. derogata on enemy-infested plants. Compared with that in plants without ants, the survival of mealybugs in shelters in the presence of natural enemies in plants with ants markedly improved. Both the protection of ants and the shelters provided by leaf rollers did not affect the survival of mealybugs in the absence of enemies in plants. Ants and leaf rollers significantly improved the survival of mealybugs in predator-infested plants, whereas no such improvement was observed in parasitoid-infested ones.

  12. A powered roller/crimper for walk-behind tractors to terminate cover crops in conservation agriculture

    Science.gov (United States)

    Roller/crimper implements have been used in large conservation farming systems to terminate cover crops near maturity and flatten them down to create a mulch through which cash crops can be planted directly into the cover residue. On small farms, tractors are usually small and less powerful relative...

  13. Corrective action plan for CAU No. 404: Roller Coaster Sewage Lagoons and North Disposal Trench, Tonopah Test Range

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    1997-07-01

    This Corrective Action Plan (CAP) provides the selected corrective action alternative and proposes the closure implementation methodology for the Roller Coaster Sewage Lagoons and North Disposal Trench Corrective Action Unit (CAU) No. 404. The site is located on the Tonopah Test Range. CAU 404 consists of two Corrective Action Sites (CAS): the Roller Coaster Lagoons (CAS No TA-03-001-TA-RC) and the North Disposal Trench (CAS No TA-21-001-TA-RC). A site map of the lagoons and trench is provided. The Roller Coaster Sewage Lagoons are comprised of two unlined lagoons that received liquid sanitary waste in 1963 from the Operation Roller Coaster Man Camp and debris from subsequent construction and range cleanup activities. The North Disposal Trench was excavated in approximately 1963 and received solid waste and debris from the man camp and subsequent construction and range cleanup activities. A small hydrocarbon spill occurred during the 1995 Voluntary Corrective Action (VCA) activities in an area associated with the North Disposal Trench CAS.

  14. Silk gland gene expression during larval-pupal transitionin the cotton leaf roller Sylepta derogate (Lepidoptera: pyralidae)

    Science.gov (United States)

    The cotton leaf roller, Sylepta derogata, is a silk-producing insect pest. While young larvae feed on the underside of leaves, the older ones roll cotton leaves and feed on the leaf edges, which defoliates cotton plants. The larvae produce silk to stabilize the rolled leaf and to balloon from used t...

  15. Solar tracking system

    Energy Technology Data Exchange (ETDEWEB)

    Okandan, Murat; Nielson, Gregory N.

    2016-07-12

    Solar tracking systems, as well as methods of using such solar tracking systems, are disclosed. More particularly, embodiments of the solar tracking systems include lateral supports horizontally positioned between uprights to support photovoltaic modules. The lateral supports may be raised and lowered along the uprights or translated to cause the photovoltaic modules to track the moving sun.

  16. Automated identification and evaluation of subtechniques in classical-style roller skiing.

    Science.gov (United States)

    Sakurai, Yoshihisa; Fujita, Zenya; Ishige, Yusuke

    2014-09-01

    The aims of the present study were (1) the development of an automated system for identifying classical-style ski subtechniques using angular rate sensors, and (2) the determination of the relationships among skiing velocity, ski course conditions, and ski subtechniques using a global navigation satellite system (GNSS) and the developed automated identification system. In the first experiment, the performance of a male cross-country skier was used to develop an automated system for identifying classical-style ski subtechniques. In the second one, the performances of five male and five female college cross-country skiers were used to validate the developed identification system. Each subject wore inertial sensors on both wrists and both roller skis, a small video camera on the helmet, and a GNSS receiver. All subjects skied a 6,900-m roller ski course using the classical-style at their maximum speed. The adopted subtechniques were identified by the automated method based on the data obtained from the sensors, and also by visual count from a video recording of the same ski run. The results showed that the automated identification method could be definitively used to recognize various subtechniques. Specifically, the system correctly identified 9,307 subtechnique cycles out of a total of 9,444 counted visually, which indicated an accuracy of 98.5%. We also measured the skiing velocity and the course slope using the GNSS module. The data was then used to determine the subtechnique distributions as a function of the inclination and skiing velocity. It was observed that male and female skiers selected double poling below 6.7° and 5.5° uphill, respectively. In addition, male and female skiers selected diagonal stride above 0.7° and 2.5° uphill, and below 5.4 m/s and 4.5 m/s velocity, respectively. These results implied that the subtechnique distribution plot could be used to analyze the technical characteristics of each skier. Key PointsThe automatic identification

  17. Roller Coaster

    Institute of Scientific and Technical Information of China (English)

    王道林

    1998-01-01

    《英汉大词典》对roll coaster(n.)的释义是:(游乐场的)环滑车道;环滑车2.急转突变的行为(或事件等)。没有附例句。对不及物动词roll coaster不仅有释义,而且附有较多的例词和例句。

  18. Roller coasters without differential equations—a Newtonian approach to constrained motion

    Science.gov (United States)

    Müller, Rainer

    2010-07-01

    Within the context of Newton's equation, we present a simple approach to the constrained motion of a body forced to move along a specified trajectory. Because the formalism uses a local frame of reference, it is simpler than other methods, making more complicated geometries accessible. No Lagrangian multipliers are necessary to determine the constraining forces. Although the method is able to deal with friction, it becomes particularly simple for conservative systems. We give an analytic expression for the constraining force for any two-dimensional frictionless trajectory that can be written in the form y = f(x). The approach is illustrated with examples from roller coaster physics, e.g. the camelback or the clothoid loop. It is possible to find analytic expressions for the constraining force in both cases.

  19. Roller coasters without differential equations-a Newtonian approach to constrained motion

    Energy Technology Data Exchange (ETDEWEB)

    Mueller, Rainer, E-mail: rainer.mueller@tu-bs.d [Technische Universitaet Braunschweig, Physikdidaktik, Pockelsstr. 11, D-38106 Braunschweig (Germany)

    2010-07-15

    Within the context of Newton's equation, we present a simple approach to the constrained motion of a body forced to move along a specified trajectory. Because the formalism uses a local frame of reference, it is simpler than other methods, making more complicated geometries accessible. No Lagrangian multipliers are necessary to determine the constraining forces. Although the method is able to deal with friction, it becomes particularly simple for conservative systems. We give an analytic expression for the constraining force for any two-dimensional frictionless trajectory that can be written in the form y = f(x). The approach is illustrated with examples from roller coaster physics, e.g. the camelback or the clothoid loop. It is possible to find analytic expressions for the constraining force in both cases.

  20. Field Assessment and Specification Review for Roller-Integrated Compaction Monitoring Technologies

    Directory of Open Access Journals (Sweden)

    David J. White

    2011-01-01

    Full Text Available Roller-integrated compaction monitoring (RICM technologies provide virtually 100-percent coverage of compacted areas with real-time display of the compaction measurement values. Although a few countries have developed quality control (QC and quality assurance (QA specifications, broader implementation of these technologies into earthwork construction operations still requires a thorough understanding of relationships between RICM values and traditional in situ point test measurements. The purpose of this paper is to provide: (a an overview of two technologies, namely, compaction meter value (CMV and machine drive power (MDP; (b a comprehensive review of field assessment studies, (c an overview of factors influencing statistical correlations, (d modeling for visualization and characterization of spatial nonuniformity; and (e a brief review of the current specifications.

  1. Hot roller embossing system equipped with a temperature margin-based controller

    Energy Technology Data Exchange (ETDEWEB)

    Kim, Seyoung, E-mail: seyoungkim@kimm.re.kr; Son, Youngsu; Lee, Sunghee; Ham, Sangyong; Kim, Byungin [Department of Robotics and Mechatronics, Korea Institute of Machinery and Materials (KIMM), Daejeon (Korea, Republic of)

    2014-08-15

    A temperature control system was proposed for hot roller embossing. The roll surface was heated using induction coils and cooled with a circulating chilled water system. The temperature of the roll surface was precisely controlled by a temperature margin-based control algorithm that we developed. Implementation of the control system reduced deviations in the roll surface temperature to less than ±2 °C. The tight temperature control and the ability to rapidly increase and decrease the roll temperature will allow optimum operating parameters to be developed quickly. The temperature margin-based controller could also be used to optimize the time course of electrical power and shorten the cooling time by choosing an appropriate temperature margin, possibly for limited power consumption. The chiller-equipped heating roll with the proposed control algorithm is expected to decrease the time needed to determine the optimal embossing process.

  2. Multi fault detection of the roller bearing using the wavelet transformand principal component analysis

    Directory of Open Access Journals (Sweden)

    Jaafar Khalaf Ali, Qusai Talib Abdulwahab, Sajjad Nayyef Abdul kareem

    2016-01-01

    Full Text Available Vibration monitoring and analysis techniques are the key features of successful predictive and proactive maintenance programs. In this work, advanced vibration analysis techniques like Wavelet transform, Principle Component Analysis (PCA and Squared Prediction Error (SPE have been used to detect the faults in bearing. Discrete Wavelet Transforms (DWT decomposes signal to high and low frequencies. PCA is employed to extract important feature and reduce dimension. SPE is used to detect the bearing faults. The experimental data is collected from SpectraQuest's Machine Fault Simulator (MFS-4 apparatus. In this study, four rollers were bearing defects (ball defect, outer race defect, inner race defect and combined defect for 1" and 3/4" bearing. From the results, the suggestion techniques can be used to detect multi-faults in the bearings. The results show that the best wavelet function is Coiflets4 in this method.

  3. The effects of the arm swing on biomechanical and physiological aspects of roller ski skating.

    Science.gov (United States)

    Hegge, Ann Magdalen; Ettema, Gertjan; de Koning, Jos J; Rognstad, Asgeir Bakken; Hoset, Martin; Sandbakk, Øyvind

    2014-08-01

    This study analyzed the biomechanical and physiological effects of the arm swing in roller ski skating, and compared leg-skating (i.e. ski skating without poles) using a pronounced arm swing (SWING) with leg-skating using locked arms (LOCKED). Sixteen elite male cross-country skiers performed submaximal stages at 10, 15 and 20kmh(-1) on a 2% inclined treadmill in the two techniques. SWING demonstrated higher peak push-off forces and a higher force impulse at all speeds, but a longer cycle length only at the highest speed (all Pski skating increases the ski forces and aerobic energy cost at low and moderate speeds, whereas the greater forces at high speed lead to a longer cycle length and smaller anaerobic contribution.

  4. Innovative roller bearings for transmissions in heavy-duty drives; Innovative Waelzlagertechnik fuer Kupplungen in Schwerantrieben

    Energy Technology Data Exchange (ETDEWEB)

    Asch, A.; Lindenthal, H. [Voith Turbo GmbH und Co. KG, Heidenheim (Germany)

    2001-07-01

    Universal joint couplings are used, e.g. in heavy-duty drives in rolling plants where hitch shock loads occur. They must be designed for maximum momentum capacity. As a rule, roller bearings have higher transmission efficiencies than sliding element bearings. The contribution describes a new technology for longer life of the bearings in which the protective effects of the universal joint are considered. [German] Kreuzgelenke sind Ausgleichskupplungen, die beispielsweise in stossbelasteten Schwerantrieben der Walzwerkstechnik eingesetzt werden. Bei diesen Schwerantrieben muessen sie in erster Linie fuer hoechste Drehmomentkapazitaet ausgelegt werden. Waelzlager bieten dabei generell hoehere Uebertragungswirkungsgrade als Alternativen mit Gleitelementen. Der Beitrag stellt eine neue Entwicklung zur gezielten Steigerung der Lagerlebensdauer vor, bei der Stuetzwirkungen der Gelenkkonstruktion beruecksichtigt werden. (orig.)

  5. Nanostructural evolution of Zn by dry roller vibration milling at room temperature

    Institute of Scientific and Technical Information of China (English)

    2006-01-01

    It remains open to date to produce stable nanostructures of single element by dry mechanical method at room temperature on a large scale. Here we report nanostructural evolution of zinc by dry roller vibration milling at room temperature, which leads to structurally near perfect zinc flakes sized 3-5 nm in diameter. The synthesized nanostructures are single crystalline, transparent, uniform, randomly oriented, almost equiaxed, and mostly free from defects. The evolution seems to open a way to optimize zinc nanostructures by the mechanical method, offer valuable references to prepare nanostructures of other metals optimally, and shed light on how to lower the size limit by mechanical milling. Single elemental metal nanostructures with excellent properties give rise to new opportunities in scientific research and development of nanotechnology.

  6. Visualization and prediction of porosity in roller compacted ribbonswith near infrared chemical imaging (NIR-CI)

    DEFF Research Database (Denmark)

    Khorasani, Milad Rouhi; Amigo Rubio, Jose Manuel; Sonnergaard, Jørn

    2015-01-01

    The porosity of roller compacted ribbon is recognized as an important critical quality attribute which has a huge impact on the final product quality. The purpose of this study was to investigate the use of near-infrared chemical imaging (NIR-CI) for porosity estimation of ribbons produced...... at different roll pressures. Two off-line methods were utilized as reference methods. The relatively fast method (oil absorption) was comparable with the more time-consuming mercury intrusion method (R2 = 0.98). Therefore, the oil method was selected as the reference off line method. It was confirmed by both...... reference methods that ribbons compressed at a higher pressure resulted in a lower mean porosity. Using NIR-CI in combination with multivariate data analysis it was possible to visualize and predict the porosity distribution of the ribbons. This approach is considered important for process monitoring...

  7. MECHANICAL DISINTEGRATION OF WHEAT STRAW BY ROLLER-PLATE GRIND SYSTEM WITH SHARP-EDGED SEGMENTS

    Directory of Open Access Journals (Sweden)

    Lukas Kratky

    2015-04-01

    Full Text Available Colloid mills and extruders are widely used for disintegrating wet fibrous biomass. However, their main disadvantages are a high energy requirement in the range of hundreds or thousands of kWh per ton of material, and the fact that they grind in process cycles. Efforts have therefore been made to design a new type of continuously operated grinder. Its disintegration principle uses a roller-plate grinding system with sharp-edged segments, where the compressive and shear forces combine to comminute the particles. Test experiments verified that the grinder disintegrates wet untreated straw to particles below 10mm in an effective manner in a single pass, with an energy requirement of 50 kWht−1 TS. A 23% increase in biogas yield was achieved, leading to a net gain in electric energy of310 kWht−1 TS.

  8. Love at first fright: partner salience moderates roller-coaster-induced excitation transfer.

    Science.gov (United States)

    Meston, Cindy M; Frohlich, Penny F

    2003-12-01

    This study examined the effects of residual nervous system arousal on perceptions of sexual attraction. Researchers approached individuals (males, n = 165; females, n = 135) at amusement parks as they were either waiting to begin or as they had just gotten off a roller-coaster ride. Participants were shown a photograph of an average attractive, opposite-gendered individual and asked to rate the individual on attractiveness and dating desirability. Participants were also asked to rate their seatmates' levels of attractiveness. Consistent with the predictions of excitation transfer theory, for males and females riding with a nonromantic partner, ratings of attractiveness and dating desirability toward the photographed individual were higher among persons exiting than entering the ride. Among persons riding with a romantic partner, there were no significant differences in attractiveness or dating desirability ratings between persons entering and exiting the ride. The findings are discussed in terms of the potential moderator effects of a salient romantic partner on excitation transfer.

  9. Elastohydrodynamic Lubrication Studies on Effects of Crowning Value in Roller Bearings

    Institute of Scientific and Technical Information of China (English)

    2001-01-01

    The purpose of this paper is to present a comparison of numerical calculations and experiment results of optical interferome try in finite line contact for the elastohydrodynamic lubrication(EHL) problem of Lundberg's profiled cylindrical roller under the con ditions of flooded state, moderate load and material parameter. It shows clearly the effects of crowning value on the variations of oil film shape and thickness. The agreement between numerical analysis and experiment results is very good. The results indicate there must be an optimum crowning value that will induce the thickest and most even oil film in EHL state for a given working condition, and this value is larger than the design value in dry contact state for the same working conditions.

  10. Degradation Assessment and Fault Diagnosis for Roller Bearing Based on AR Model and Fuzzy Cluster Analysis

    Directory of Open Access Journals (Sweden)

    Lingli Jiang

    2011-01-01

    Full Text Available This paper proposes a new approach combining autoregressive (AR model and fuzzy cluster analysis for bearing fault diagnosis and degradation assessment. AR model is an effective approach to extract the fault feature, and is generally applied to stationary signals. However, the fault vibration signals of a roller bearing are non-stationary and non-Gaussian. Aiming at this problem, the set of parameters of the AR model is estimated based on higher-order cumulants. Consequently, the AR parameters are taken as the feature vectors, and fuzzy cluster analysis is applied to perform classification and pattern recognition. Experiments analysis results show that the proposed method can be used to identify various types and severities of fault bearings. This study is significant for non-stationary and non-Gaussian signal analysis, fault diagnosis and degradation assessment.

  11. Four-channel accelerometer for diagnostic testing of roller bearings of mine blowers

    Energy Technology Data Exchange (ETDEWEB)

    Lebiedzki, A.

    1992-01-01

    Discusses design, operation and use of a four-channel vibroacoustic monitoring system for control of the main blowers driven by electric motors with a revolution rate of 500 rpm and 1 MW power. The PPWa-22PN piezoelectric acceleration converters manufactured by the EKCEL plant in Katowice were used. The converters were equipped with built-in preamplifiers that enabled measuring cables up to 100 m long to be used. The converters were mounted on the casings of blower roller bearings. Rising acoustic emission and mechanical vibrations measured and recorded by the system were signalled to a driver by three lamps (green, yellow and red ones) showing acoustic emission increase by 2 dB, 4 dB or 6 dB. Reliability of blower control using the system is discussed. 3 refs.

  12. DEVELOPMENT OF TRANSMISSION QUALITY CONTROL CHARTS FOR SINGLE ROLLER- TO- CAM INTERMITTENT MOTION MECHANISMS

    Directory of Open Access Journals (Sweden)

    DR. K. S. TRIPATHI

    2010-10-01

    Full Text Available This paper addresses itself to a portion of a systematic investigation of a very simple intermittent motion mechanism consisting of a single roller crank and a single cam. The mechanism presented in this paper, being continuous contact type, does not have dynamic problems such as sudden jerk experienced in traditional genevamechanism. The cam being the output and the cam radius being a varying quantity, the conventional transmission angle cannot be used. A new rational transmission index is introduced in the present nvestigation. Here transmission index charts are developed as design aids in synthesizing a law of motion ( in general and not just forintermittent motion mechanisms . The variation of transmission index along the motion law curve may be readily seen by superimposing the chosen motion law on the transmission index chart. Appropriate changes may then be made in the motion law as found necessary.

  13. OPTIMAL DESIGNS AND CAPABILITY LIMITS OF SINGLE ROLLER-TO-CAM INDEXING MECHANISMS FOR THREE DWELLS

    Directory of Open Access Journals (Sweden)

    DR. K. S. TRIPATHI

    2010-12-01

    Full Text Available This paper aims to investigate the continuous contact single roller-to-cam indexing mechanism for optimal designs and capability limits, based on generic transmission and curvature constraint for three dwell periods. First of all, the paper determines the solutions of the problems associated with multiple dwells and then develops optimal designs for three maximum extent dwell periods with equal indexing angles with curvature and transmission constraints. Next, stipulating that the three dwell periods should be equal; iteration is done. This gives optimal designs for three equal maximized dwells with equal indexing periods with curvature and transmission constraints. Final information in the form of capability limits will be very helpful to those who search for various alternative indexing mechanisms for several applications of automatic and packaging industries.

  14. Performance Analysis of Functionally Graded Coatings in Contact with Cylindrical Rollers

    Directory of Open Access Journals (Sweden)

    Reza Jahedi

    2015-01-01

    Full Text Available This work presents finite element analysis (FEA and results for rolling contact of a cylindrical roller on an elastic substrate coated by functionally graded material (FGM. The rolling process and the graded coating material property and layers arrangement are modeled using finite element codes which lead to a new methodology. This novel methodology provides a trend in determining surface contact stresses, deformations, contact zones, and energy dissipation through the contact area. Effects of stiffness ratio, friction, and exponentially variation of material property on the contact stresses and deformations are studied. Some of the results are verified with analytical solutions. The study results may be beneficial in graded coated cylindrical components analysis against rolling contact failure and wear.

  15. Failure of the chassis of roller skates for agonistic figure skating

    Directory of Open Access Journals (Sweden)

    Giorgio Olmi

    2015-04-01

    Full Text Available The subject of this work was to investigate the early failure, which occurred in the chassis of a roller skate for figure skating. The paper deals with the preliminary analysis of the crack and with the integrated approach, which had to be followed to overcome the problem. Literature in the fields of physiology and biomechanics was studied to correctly simulate the load distribution on the chassis. Finite element simulation, experimental stress analysis and analytical modeling of impact phenomena had to be combined together to estimate the entity of dynamic loads and the corresponding state of stress. The analysis led to the determination of the primary cause of failure, bending fatigue, and to the suggestion of a simple solution to improve and optimize the project.

  16. Edge coating apparatus with movable roller applicator for solar cell substrates

    Science.gov (United States)

    Pavani, Luca; Abas, Emmanuel

    2012-12-04

    A non-contact edge coating apparatus includes an applicator for applying a coating material on an edge of a solar cell substrate and a control system configured to drive the applicator. The control system may drive the applicator along an axis to maintain a distance with an edge of the substrate as the substrate is rotated to have the edge coated with a coating material. The applicator may include a recessed portion into which the edge of the substrate is received for edge coating. For example, the applicator may be a roller with a groove. Coating material may be introduced into the groove for application onto the edge of the substrate. A variety of coating materials may be employed with the apparatus including hot melt ink and UV curable plating resist.

  17. Analysis of 3D curve expansion of conical cam with oscillating tapered roller follower

    Institute of Scientific and Technical Information of China (English)

    2007-01-01

    This paper focuses on the analysis of running conditions and machining processes of conical cam with oscillating follower. We point out the common errors existing in the design and machining of the widely used plane expansion method of conical cam trough-out line. We show that the motion can be divided into two parts, i.e. the oscillating motion of oscillating bar and the rotary motion of oscillating bar relative to the conical cam. By increasing the rotary motion of oscillating bar, the motion path of tapered roller on oscillating bar (i.e. contour surface of conical cam) can be expanded on the cylinder. Based on these analyses,we present a creative and effective designing and machining method for 3D curve expansion of conical cam with oscillating follower.

  18. Hot roller embossing system equipped with a temperature margin-based controller.

    Science.gov (United States)

    Kim, Seyoung; Son, Youngsu; Lee, Sunghee; Ham, Sangyong; Kim, Byungin

    2014-08-01

    A temperature control system was proposed for hot roller embossing. The roll surface was heated using induction coils and cooled with a circulating chilled water system. The temperature of the roll surface was precisely controlled by a temperature margin-based control algorithm that we developed. Implementation of the control system reduced deviations in the roll surface temperature to less than ±2 °C. The tight temperature control and the ability to rapidly increase and decrease the roll temperature will allow optimum operating parameters to be developed quickly. The temperature margin-based controller could also be used to optimize the time course of electrical power and shorten the cooling time by choosing an appropriate temperature margin, possibly for limited power consumption. The chiller-equipped heating roll with the proposed control algorithm is expected to decrease the time needed to determine the optimal embossing process.

  19. Remote reading of roller counter displays; Releve a distance des compteurs

    Energy Technology Data Exchange (ETDEWEB)

    Kettner, Th.; Wolff, J.; Steiner, K. [Elster Produktion GmbH, Steinernstr. (Germany); Ewerlin, U. [Flow Group Systemtechnik GmbH, Dortmund (Germany)

    2000-07-01

    The remote reading of mechanical custody transfer meters means that an electronically reproduced readout is transmitted. Usually pulses are accumulated to provide the reproduction. However, the exact non-corrected meter consumption displayed at the index of the mechanical meter is unknown at the location where the electronically transferred data is collected. To exclude any distortion of the remotely read information, distribution and transmission companies occasionally request a proof of whether the data is correct. The remote reading of roller counters by an optoelectronic encoder technology leads to that proof. The exact non-corrected meter readout can be compared with the reproduced one. The encoder technology, the integration of meter on-line monitoring and BUS compatibility is discussed. (authors)

  20. Roller compaction: Effect of morphology and amorphous content of lactose powder on product quality.

    Science.gov (United States)

    Omar, Chalak S; Dhenge, Ranjit M; Osborne, James D; Althaus, Tim O; Palzer, Stefan; Hounslow, Michael J; Salman, Agba D

    2015-12-30

    The effect of morphology and amorphous content, of three types of lactose, on the properties of ribbon produced using roller compaction was investigated. The three types of lactose powders were; anhydrous SuperTab21AN, α-lactose monohydrate 200 M, and spray dried lactose SuperTab11SD. The morphology of the primary particles was identified using scanning electron microscopy (SEM) and the powder amorphous content was quantified using NIR technique. SEM images showed that 21AN and SD are agglomerated type of lactose whereas the 200 M is a non-agglomerated type. During ribbon production, an online thermal imaging technique was used to monitor the surface temperature of the ribbon. It was found that the morphology and the amorphous content of lactose powders have significant effects on the roller compaction behaviour and on ribbon properties. The agglomerated types of lactose produced ribbon with higher surface temperature and tensile strength, larger fragment size, lower porosity and lesser fines percentages than the non-agglomerated type of lactose. The lactose powder with the highest amorphous content showed to result in a better binding ability between the primary particles. This type of lactose produced ribbons with the highest temperature and tensile strength, and the lowest porosity and amount of fines in the product. It also produced ribbon with more smooth surfaces in comparison to the other two types of lactose. It was noticed that there is a relationship between the surface temperature of the ribbon during production and the tensile strength of the ribbon; the higher the temperature of the ribbon during production the higher the tensile strength of the ribbon.

  1. Effect of formulation composition on the properties of controlled release tablets prepared by roller compaction.

    Science.gov (United States)

    Hariharan, Madhusudan; Wowchuk, Christina; Nkansah, Paul; Gupta, Vishal K

    2004-07-01

    This study discusses the effect of formulation composition on the physical characteristics and drug release behavior of controlled-release formulations made by roller compaction. The authors used mixture experimental design to study the effect of formulation components using diclofenac sodium as the model drug substance and varying relative amounts of microcrystalline cellulose (Avicel), hydroxypropyl methylcellulose (HPMC), and glyceryl behenate (Compritol). Dissolution studies revealed very little variability in drug release. The t70 values for the 13 formulations were found to vary between 260 and 550 min. A reduced cubic model was found to best fit the t70 data and gave an adjusted r-square of 0.9406. Each of the linear terms, the interaction terms between Compritol and Avicel and between all three of the tested factors were found to be significant. The longest release times were observed for formulations having higher concentrations of HPMC or Compritol. Tablets with higher concentrations of Avicel showed reduced ability to retard the release of the drug from the tablet matrix. Crushing strength showed systematic dependence on the formulation factors and could be modeled using a reduced quadratic model. The crushing strength values were highest at high concentrations of Avicel, while tablets with a high level of Compritol showed the lowest values. A predicted optimum formulation was derived by a numerical, multiresponse optimization technique. The validity of the model for predicting physical attributes of the product was also verified by experiment. The observed responses from the calculated optimum formulation were in very close agreement with values predicted by the model. The utility of a mixture experimental design for selecting formulation components of a roller compacted product was demonstrated. These simple statistical tools can allow a formulator to rationally select levels of various components in a formulation, improve the quality of products, and

  2. Roller compaction process development and scale up using Johanson model calibrated with instrumented roll data.

    Science.gov (United States)

    Nesarikar, Vishwas V; Patel, Chandrakant; Early, William; Vatsaraj, Nipa; Sprockel, Omar; Jerzweski, Robert

    2012-10-15

    Roller compaction is a dry granulation process used to convert powder blends into free flowing agglomerates. During scale up or transfer of roller compaction process, it is critical to maintain comparable ribbon densities at each scale in order to achieve similar tensile strengths and subsequently similar particle size distribution of milled material. Similar ribbon densities can be reached by maintaining analogous normal stress applied by the rolls on ribbon for a given gap between rolls. Johanson (1965) developed a model to predict normal stress based on material properties and roll diameter. However, the practical application of Johanson model to estimate normal stress on the ribbon is limited due to its requirement of accurate estimate of nip pressure i.e. pressure at the nip angle. Another weakness of Johanson model is the assumption of a fixed angle of wall friction that leads to use of a fixed nip angle in the model. To overcome the above mentioned limitations, we developed a novel approach using roll force equations based on a modified Johanson model in which the requirement of pressure value at nip angle was eliminated. An instrumented roll on WP120 roller compactor was used to collect normal stress data measured at three locations across the width of a roll (P1, P2, P3), as well as gap and nip angle data on ribbon for placebo and various active blends along with corresponding process parameters. The nip angles were estimated directly using experimental pressure profile data of each run. The roll force equation of Johanson model was validated using normal stress, gap, and nip angle data of the placebo runs. The calculated roll force values compared well with those determined from the roll force equation provided for the Alexanderwerk(®) WP120 roller compactor. Subsequently, the calculation was reversed to estimate normal stress and corresponding ribbon densities as a function of gap and RFU (roll force per unit roll width). A placebo model was developed

  3. Applications of Roller Laser Hardening in Shuigang%轧辊激光强化技术在水钢的应用

    Institute of Scientific and Technical Information of China (English)

    张育茂

    2011-01-01

    轧辊激光强化是将强激光束照射到轧辊表面,使轧辊产生组织相变硬化或在表面形成超细化、高强韧度、高耐磨的合金层。本文介绍了轧辊的激光强化机理和在水钢轧钢生产应用中所取得的效果。%Roll laser strengthening is irradiation of laser beam to the roller surface. As a result, the phase transi- tion hardens will occur in the roller or a layer of extremely fine alloy metal with high tenacity and high wear-ability will be formed on the roller surface. This paper introduces the laser strengthening mechanism for rollers and the effect from production in Shuicheng'Iron & Steel Co Ltd.

  4. Comparison of the centrifugal and roller pump in elective coronary artery bypass surgery--a prospective, randomized study with special emphasis upon platelet activation.

    Science.gov (United States)

    Andersen, Knut S; Nygreen, Else L; Grong, Ketil; Leirvaag, Beryl; Holmsen, Holm

    2003-12-01

    Objective--Evaluation of the centrifugal pump vs roller pump concerning effects upon platelet function, hemolysis and clinical outcome in elective coronary artery bypass surgery. Design--Thirty-four patients were randomized to centrifugal or roller pump. Platelet activation was studied by flow cytometry before, during and up to 3 days after bypass. Results--Duration of bypass, ischemic period, peripheral anastomoses, hospital stay and mortality did not differ. In roller pump patients, platelet aggregates increased by 250% between end of bypass and 3 h postoperatively (p centrifugal pump group, these changes were not significant. Hemolysis increased (20%) at end of bypass and 3 h postoperatively (p centrifugal pump patients, indicating higher susceptibility to postoperative thrombotic complications with the roller pump. Otherwise, there was no clinical evidence for superiority of the centrifugal pump.

  5. Innovational repairing technics successfully applied to continuous casting rollers%连铸辊创新修复工艺的成功应用

    Institute of Scientific and Technical Information of China (English)

    石云霄; 黄挺; 王勇

    2011-01-01

    In order to solve the problem of continuous casting roller failure caused by the introduction of conticaster thin roller closely-arranged technology, Baosteel Equipment Maintenance Department, proceeding from the quality control and cost reduction, successfully broke through the bottleneck which had influenced the running of continuous casting equipments in Baosteel for long time by the aid of "roller core and roller cover segregation repairing technology ".%为解决连铸机细辊密排技术引进以后的连铸辊故障问题,宝钢设备维护部门从控制质量、节约成本的角度出发,运用辊芯辊套修复技术创新手段,成功解决了影响宝钢连铸设备顺行的技术瓶颈问题.

  6. Contact of Tapered Roller with Logarithmic Profile%对数修形圆锥滚子的接触分析

    Institute of Scientific and Technical Information of China (English)

    王爱林; 王庆九; 汪久根

    2012-01-01

    轴承的滚子修形是减小滚子边缘应力集中、提高滚动轴承疲劳寿命的重要措施。本文中建立了圆锥滚子接触的力学模型,依据圆锥滚子与内圈的接触方程,计算分析了接触应力和表层Mi-ses应力分布,并对比讨论了实际载荷大于或小于设计载荷时的接触应力分布和Mises应力场的变化。结果表明:对数修形后的圆锥滚子其端部应力集中情况得到了显著改善;且对于不同载荷的轴承要设计不同的修形量,以避免边缘效应的发生、提高接触疲劳寿命。%The profile design of the rollers of rolling bearings is an important method that can reduce the stress concentration at the edge of the roller and improve the fatigue life of bearings.The contact model of profiled tapered roller was established,then based on the equations of the problem for contact between roller and inner ring,the distributions of contact stress and Mises stress field and their variations with normal load were examined.The comparison of the distributions of above stress fields show that,for the logarithmic tapered roller,the stress concentration of contact stress and the Mises stress inside subsurface at the roller ends is improved;and that the roller profile and blend value should be designed in terms of load to avoid edge effect and prolong the fatigue life of tapered rollers.

  7. Finite element analysis of strength for high capacity roller dollies%大载荷滚轮推车强度有限元分析

    Institute of Scientific and Technical Information of China (English)

    郭子逸; 郑卫刚; 龚苏生

    2012-01-01

    In combination with UC 3D modeling software and ADINA software, the finite element models respectively for both the integral dolly and double-roller of high capacity roller dolly are established in the paper. Then based on the nonlinear contact method, the contact stress of the roller contact surface is analyzed. With comparison of the calculation results under the two conditions, it's concluded that the finite element result of double-roller is close to that by the traditional Hertz theory. The static strength calculation for the roller dolly is performed as well, providing theoretical basis for the design of high capacity roller dolly.%将UG三维建模软件和ADINA软件相结合,分别建立了大载荷滚轮推车的整体和双滚轮的有限元模型.基于非线性接触算法对滚轮接触面的接触应力进行分析,对比2种情况下的计算结果,得到双滚子的有限元结果与传统的赫兹理论较接近.同时对滚轮推车的结构静强度进行了计算,为大载荷滚轮推车的设计提供理论依据.

  8. Custom Modeling for Roller of Brake Tester Based on AMESet%基于AMESet的制动检验台滚筒自定义建模

    Institute of Scientific and Technical Information of China (English)

    刘一峰; 李玉兰

    2014-01-01

    It need representing physical model of the rollers accurately and vividly, in form of one submodel in some element submodel list, when analyzing on roller opposite forces type brake tester with AMESim. Based on dynamics analysis, functions of roller submodel is given, according to the principle of AMESim modeling. The component is designed to represent roller submodel. Custom modeling for roller is implemented with AMESet. Test in AMESim verifies that custom submodel of roller conforms to AMESim component rules, calculates in correction, meets the functional requirements, and achieves the expected goal.%在AMESim中进行滚筒反力式制动检验台检测过程的仿真分析,需要以元件子模型的形式对滚筒的物理模型进行准确、形象的表示。在动力学分析的基础上,根据AMESim的建模原理给出了滚筒子模型应具有的功能,设计了代表滚筒子模型的元件,基于AMESet实现了滚筒的自定义建模。在AMESim中的验证表明,滚筒的自定义子模型符合AMESim的元件规则,计算正确,满足功能需求,实现了预期目标。

  9. Tracked Vehicle - Soft Soil Interactions and Design Sensitivities for Path Clearing Systems Utilizing Multi-Body Dynamics Simulation Methods

    Science.gov (United States)

    2013-08-13

    radius – Pot hole: 17 cm deep x 60 cm long – V-ditch: 1.4 m deep x 7.8 m long – Grades: 40%-60% – Cross-country ( clay only) 13 August 2013 3...band track – Flail or roller-rake path clearing implement. • Soft soil mobility events conducted over clay and sand: – Half-round bump: 17.5 cm...Soil Property Sand Clay Exponent Number (n) [] 1.1 0.13 Terrain Stiffness (kC) [kN/m1+n] 0.99 12.7 Terrain

  10. Renewable Energy Tracking Systems

    Science.gov (United States)

    Renewable energy generation ownership can be accounted through tracking systems. Tracking systems are highly automated, contain specific information about each MWh, and are accessible over the internet to market participants.

  11. Forward tracking detectors

    Indian Academy of Sciences (India)

    Klaus Mönig

    2007-11-01

    Forward tracking is an essential part of a detector at the international linear collider (ILC). The requirements for forward tracking are explained and the proposed solutions in the detector concepts are shown.

  12. 辊底式热处理炉炉底辊在线更换检修的探索%Practice of On-Line Roller Replacement for Roller Hearth Heat Treatment Furnace

    Institute of Scientific and Technical Information of China (English)

    王国强; 张许豪

    2014-01-01

    For the frequent breakage failures of hearth roller of heat treatment furnaces in Wugang new plate mill, the paper analyzes the advantages and disadvantages of current hearth roller replacement method,puts forward the easy and feasible hearth roller on-line replacement solution according to production and actual site conditions,achieves the replacement without furnace shut down,which not only greatly shortens the down time,but also prevents large amount of energy consumption and receives a good result.%针对舞钢新轧钢厂热处理线炉底辊频繁断裂的问题,分析了现行炉底辊更换方法的优缺点,结合生产及现场实际,提出了简单易行的炉底辊在线更换方案,实现了不停炉更换炉底辊,不仅缩短了停炉时间,还避免了能源消耗,取得了良好效果。

  13. Application of Dang Van criterion to rolling contact fatigue in wind turbine roller bearings under elastohydrodynamic lubrication conditions

    DEFF Research Database (Denmark)

    Cerullo, Michele

    2014-01-01

    A 2D plane strain finite element program has been developed to investigate very high cycle fatigue in wind turbine roller bearings due to rolling contact. Focus is on fatigue in the inner ring, where the effect of residual stresses and hardness variation along the depth is accounted for. Both...... classic Hertzian and elastohydrodynamic lubrication theories have been used to model the pressure distribution acting on the inner raceway and results are compared according to the Dang Van multiaxial fatigue criterion. The contact on the bearing raceway is simulated by substituting the roller...... its values to the fatigue limit parameters for the material. It is found that both for Hertzian and elastohydrodynamic lubrication contacts, the Dang Van criterion predicts that fatigue failure will first occur in the subsurface region and that, regardless of the specific pressure distribution used...

  14. Temperature Distribution and Thermal Deformation of the Crystallization Roller Based on the Direct Thermal-Structural Coupling Method

    Science.gov (United States)

    Pan, Liping; He, Zhu; Li, Baokuan; Zhou, Kun; Sun, Ke

    2017-03-01

    The temperature distribution and the thermal deformation of the crystallization roller have a significant effect on the forming process of the thin steel strip. Finite element analysis has been used to simulate the temperature distribution and the thermal deformation in a crystallization roller through the direct thermal-structural coupling analysis method. Various parameters, such as different rotational velocities, diverse locations of cooling water pipes, and typical velocities of cooling water have been systematically investigated. It is found that the temperature and the equivalent stress of the outer surface reach the steady state after 30 s of rotations, and they are influenced remarkably by the factors of rotational velocity and cooling water pipe depth. Meanwhile, the radial displacement approaches the steady state after 300 s of revolutions and is significantly affected by the cooling water velocity.

  15. Temperature Distribution and Thermal Deformation of the Crystallization Roller Based on the Direct Thermal-Structural Coupling Method

    Science.gov (United States)

    Pan, Liping; He, Zhu; Li, Baokuan; Zhou, Kun; Sun, Ke

    2016-12-01

    The temperature distribution and the thermal deformation of the crystallization roller have a significant effect on the forming process of the thin steel strip. Finite element analysis has been used to simulate the temperature distribution and the thermal deformation in a crystallization roller through the direct thermal-structural coupling analysis method. Various parameters, such as different rotational velocities, diverse locations of cooling water pipes, and typical velocities of cooling water have been systematically investigated. It is found that the temperature and the equivalent stress of the outer surface reach the steady state after 30 s of rotations, and they are influenced remarkably by the factors of rotational velocity and cooling water pipe depth. Meanwhile, the radial displacement approaches the steady state after 300 s of revolutions and is significantly affected by the cooling water velocity.

  16. Comparison of Roller Burnishing Method with Other Hole Surface Finishing Processes Applied on AISI 304 Austenitic Stainless Steel

    Science.gov (United States)

    Akkurt, Adnan

    2011-08-01

    Component surface quality and selection of the optimum material are the main factors determining the performance of components used in machine manufacturing. The level of hole surface quality can be evaluated by the measurements regarding surface roughness, micro-hardness, and cylindricity. In this study, data had been obtained for different hole drilling methods. The characteristics of materials obtained after applications were compared for different hole-finishing processes to identify best hole drilling method. AISI 304 austenitic stainless steel material was used. Surface finishing of holes were performed using drilling, turning, reaming, grinding, honing, and roller burnishing methods. The results of the study show that the roller burnishing method gives the best results for mechanical, metallurgical properties, and hole surface quality of the material. On the other hand, the worst characteristics were obtained in the drilling method.

  17. Modeling of Roller Bracket on SolidWorks%基于SolidWorks的上托辊架三维建模

    Institute of Scientific and Technical Information of China (English)

    邵娜

    2015-01-01

    介绍一种利用SolidWorks软件中的焊件设计模块对带式输送机托辊架进行建模的方法,该方法操作简单、快捷。通过对上托辊架的三维建模以及虚拟装配,可以很直观地检查出设计中的错误,提高设计效率。%Introduces a method of roller bracket model of belt conveyor by using weldment design module of SolidWorks software, the method is simple and fast. Through the roller frame 3D modeling and virtual assembly, can be very intuitive to check out the design errors and improve design efficiency.

  18. Performance of ATLAS tracking

    CERN Document Server

    Roe, Shaun; The ATLAS collaboration

    2017-01-01

    Run-2 of the Large Hadron Collider (LHC) has provided new challenges to track and vertex reconstruction with higher centre-of-mass energies and luminosity leading to increasingly high-multiplicity envi-ronments. This talk provides an overview of the tracking performance, highlighting tracking improvements due to the Insertable B-Layer (IBL) and the introduction of time-dependent alignment.

  19. ROLLER COASTER RETINOPATHY: CASE REPORT OF SYMPTOMATIC BILATERAL INTRARETINAL HEMORRHAGES AFTER SHAKING INJURY IN AN OTHERWISE HEALTHY ADULT

    OpenAIRE

    Yogin P. Patel; Saraf, Steven S.; Desai, Ankit; Desai, Uday R.

    2016-01-01

    Purpose: Traumatic head injuries not involving the eye have been known to cause retinal injury through multiple mechanisms. Abusive head trauma remains the prototypical example. We propose to demonstrate the first case of bilateral multiple retinal hemorrhages in a young healthy adult related to riding multiple theme park roller coasters. Methods: The patient was evaluated with a complete ophthalmic examination including dilated extended ophthalmoscopy, fluorescein angiography, optical cohere...

  20. Comparing Variability of Parameters between Roller Bed Brakes Testers and Dynamometric Platform of Ministry Of Transport Facilities

    Directory of Open Access Journals (Sweden)

    Senabre C

    2015-01-01

    Full Text Available This study gives a comparison between which parameters may vary when braking on two different Ministry of Transport (MOT brake testers, such as roller bed brake tester and dynamometric platform. A comparative study between both types of brake testers have been carried out by the mechanical engineering staffs at the mechanical laboratory at the Miguel Hernández University in Elche to determinate which parameters can vary the result of the test.

  1. 带式输送机托辊的参数化设计%Parametric design on belt conveyor roller

    Institute of Scientific and Technical Information of China (English)

    冷岳峰

    2013-01-01

    To solve parametric drawing problem of belt conveyor roller design,uses inlays language VBA principle and method to achieves the parametric design process of the belt conveyor roller components. uses inlays language VBA to writing drawing program,using this application,designers can input the corresponding parameters to get the result of roller drawing to get belt conveyor roller drawings and assembly drawings and other drawing results.The parametric design method reducts design cycle to some kinds of components, reduce the designer’s drawing labour intensity ,and enhances the drawing quality and efficiency.%  为解决带式输送机托辊设计中的参数化绘图问题,采用 VBA 对带式输送机托辊进行参数化设计的原理和方法,实现在 AutoCAD2004环境下,利用 AutoCAD 自带的二次开发软件包 VBA 编制绘图程序,利用此应用程序,设计人员只需输入几个相应的设计参数就可得到托辊完整的零件图和装配图等绘图结果。这种参数化设计方法不仅缩短了对某类零件的设计周期,减轻设计人员绘图劳动强度,同时还提高设计的质量和效率。

  2. The pathology of whiplash maculopathy and retinopathy : Illustrated observations derived from a fatal roller-coaster accident.

    Science.gov (United States)

    Parsons, M A; Talbot, J F; Mudhar, H S; Rutty, Guy N

    2005-03-01

    We present a single case report of a 20-year-old female who died following a severe whiplash head and neck injury sustained during a roller-coaster incident. We present the pathology of her eyes, which we believe to be the first pathological illustration of whiplash maculopathy and retinopathy to be reported within the medical literature. This article presents the macroscopic and microscopic pathology identified in this case and discusses the possible causation of the findings.

  3. Investigation of Lift Bonding for Roller-Compacted Concrete with Low Normal Loads at Variable Placement Times

    Science.gov (United States)

    2013-04-01

    concrete materials together. The maximum capacity of a single batch in this mixer is approximately 27 ft3. The aggregates are dumped from hydraulically...distributed into the mixer . Following the concrete sand, the ASTM #57 crushed limestone was weighed and added to the mixer . The two aggregates were...ER D C/ G SL T R -1 3 -7 Investigation of Lift Bonding for Roller- Compacted Concrete with Low Normal Loads at Variable Placement Times

  4. Influence of thermal crown of guide roller in continuous annealing furnace on roller shape and stress distribution of strip steel%连退炉导向辊热凸度对辊形及带钢应力分布的影响

    Institute of Scientific and Technical Information of China (English)

    杨静; 苏岚; 唐获; 江海涛; 王辉; 林承江

    2011-01-01

    In order to effectively control the thermal crown of guide roller in continuous annealing furnace and reduce the running deviation and buckling deformation of strip steel, a single taper roller was chosen as the research object, and MARC finite element software was used to quantitatively calculate the thermal crown of guide roller with different temperature differences in heating and rapid cooling sections. Meanwhile, the influence of thermal crown on the shape of guide roller and stress distribution of strip steel was studied. It is found that the thermal crown of guide roller tends to increase linearly with increasing the temperature difference on guide roller. In the heating section, with increasing the temperature difference on guide roller, the shape of guide roller after generating the thermal crown becomes double taper, single taper or "M" one. In addition, the distribution of both tensile and maximum stresses for strip steel changes with increasing the temperature difference on guide roller. In the rapid cooling section, the guide roller changes into double taper roller after generating the thermal crown. Moreover, the thermal crown of guide roller has some effect on the tensile and maximum stresses of strip steel, but has no influence on their distribution.%为了更有效地控制连退炉内导向辊热凸度和改善带钢的跑偏及瓢曲变形,以单锥度辊为研究对象,运用MARC有限元软件,定量计算了在加热段和快冷段不同导向辊温差时的导向辊热凸度及其对导向辊辊形和带钢应力分布的影响.研究发现:导向辊热凸度随导向辊温差增大呈直线上升的趋势.在加热段,随着导向辊温差的增大,导向辊产生热凸度后的形状分别为双锥度辊、单锥度辊和"M"型辊,带钢张应力和带钢最大应力分布随着导向辊温差的增大而改变;在快冷段,导向辊产生热凸度后变为双锥度辊,导向辊热凸度会影响带钢张应力值和最大应力值,但不影响其分布.

  5. A Research on Design of The Height of the Roller Coaster%过山车的高度设计研究

    Institute of Scientific and Technical Information of China (English)

    马良才

    2015-01-01

    在游乐场中,过山车十分常见,过山车属于刺激而又惊险的游戏项目。在过山车高速行驶的过程中,已经过山车不断翻滚的过程中,人们会提心吊胆。在过山车整个项目的建设过程中,其设计环节、施工环节、试验环节等都十分重要,尤其是过山车的设计环节。过山车的设计决定了过山车整体工程的质量,更关系到过山车的安全,在过山车项目的设计过程中,过山车的高度设计至关重要,恰当的高度设计不仅能够使人们感受到刺激和惊险,还可以有效保障人们的安全。%In the playground, the roller coaster is very common, riding a roller coaster is an exciting and thrilling play. During the running of roller coaster and in the process of the continuous rolling of the roller coaster, people will be in fear. During the whole construction process of the roller coaster , the design , construction , trial and other links are very important, especially the link of design . The design of roller coaster determines the quality of overall project of the roller coaster, and more concerns the safety of roller coaster, in the design process of the roller coaster, the design of height of the roller coaster design is vital, the design of the appropriate height can not only make people feel the exciting and thrilling, but also effectively guarantee the safety of the people.

  6. An Analysis of US Emergency Department Visits From Falls From Skiing, Snowboarding, Skateboarding, Roller-Skating, and Using Nonmotorized Scooters.

    Science.gov (United States)

    Nathanson, Brian H; Ribeiro, Kara; Henneman, Philip L

    2016-07-01

    We analyzed the US incidence of emergency department (ED) visits and hospitalizations for falls from skiing, snowboarding, skateboarding, roller-skating, and nonmotorized scooters in 2011. The outcome was hospital admission from the ED. The primary analysis compared pediatric patients aged 1 to 17 years to adults aged 18 to 44 years. The analysis used ICD-9 E-codes E885.0 to E885.4 using discharge data from the Nationwide Emergency Department Sample, Healthcare Cost and Utilization Project, Agency for Healthcare Research and Quality. Approximately 214 000 ED visits met study criteria. Skiing injuries had the highest percentage of hospitalizations (3.30% in pediatric patients and 6.65% in adults 18-44 years old). Skateboard and snowboard injuries were more likely to require hospitalization than roller skating injuries in pediatric patients (odds ratio = 2.42; 95% CI = 2.14-2.75 and odds ratio = 1.83; 95% CI =1.55-2.15, respectively). In contrast, skateboard and snowboard injuries were less severe than roller-skating injuries in adults.

  7. ROLLER COASTER RETINOPATHY: CASE REPORT OF SYMPTOMATIC BILATERAL INTRARETINAL HEMORRHAGES AFTER SHAKING INJURY IN AN OTHERWISE HEALTHY ADULT.

    Science.gov (United States)

    Patel, Yogin P; Saraf, Steven S; Desai, Ankit; Desai, Uday R

    2016-01-01

    Traumatic head injuries not involving the eye have been known to cause retinal injury through multiple mechanisms. Abusive head trauma remains the prototypical example. We propose to demonstrate the first case of bilateral multiple retinal hemorrhages in a young healthy adult related to riding multiple theme park roller coasters. The patient was evaluated with a complete ophthalmic examination including dilated extended ophthalmoscopy, fluorescein angiography, optical coherence tomography, and fundus photography. The patient was found to have a bilateral symptomatic macular retinopathy characterized by multiple intraretinal hemorrhages. Given the lack of other systemic findings and negative medical workup, her signs and symptoms were thought to be attributed to the same day attendance of a theme park and riding of multiple roller coasters. Theme park roller coasters, as well as other attractions, may affect the eye at the vitreoretinal interface. This type of acceleration-deceleration injury should be considered in the differential of an adolescent or adult patient with retinal hemorrhage in the absence of other pathologic processes to explain clinical findings.

  8. Welding Squeezing Roller Adjustment for HFW Pipe%高频焊管焊接挤压辊的调整

    Institute of Scientific and Technical Information of China (English)

    朱斌燕; 于宾; 路广平; 任国庆; 翁文

    2011-01-01

    Aiming at welding squeezing roller pass characteristics of high frequency longitudinal seam welded pipe, the method of adjusting welding squeezing roller according to the different specifications were introduced to produce the welded pipe. Combined with the forming process characteristics of high frequency longitudinal seam welded pipe, a method of observing metal flown line of welding zone in fracture section to determine V-apex condition of strip edges end during welding was put forward, and specific methods of adjusting squeezing roller in different V-apex condition were given%针对高频焊管焊接挤压辊的孔型特点,介绍了生产不同规格焊管时焊接挤压辊的调整方法.结合高频焊管的成型工艺特点,提出了通过观察断面焊接区的金属流线方法,判定带钢边部端面焊接过程中合缝状态,并给出了不同合缝状态下调整挤压辊的具体办法.

  9. In vivo histological evaluation of fractional ablative microplasma radio frequency technology using a roller tip: an animal study.

    Science.gov (United States)

    Li, Xiaodan; Fang, Lin; Huang, Luping

    2015-12-01

    The aim of the present study is to investigate the histological characteristics associated with microplasma radio frequency (MPRF) technology in an animal study using different treatment parameters. Two white piglets, aged 6 months, received MPRF treatment using a roller tip; the treatment site was located on the dorsal skin. Four groups of parameters were adopted regarding the performance of the treatment at four zones on the dorsum. Immediately, at 7 days and at 1, 3, and 6 months posttreatment, we observed the healing process and obtained specimens from each treatment zone. Hematoxylin and eosin and Masson stainings of histological sections were performed to assess the degree of tissue injury, the heat effect, the healing process, and neocollagenesis. Heat shock protein (HSP) was also detected using immunohistochemistry. The roller tip generated a fractional treatment, which had a general trend involving an increase in depth and width with increasing pulse energy and decreasing sliding speed. During the wound healing process, dermal neocollagenesis was stimulated, remodeled, and matured gradually. The expression of HSP47 and HPS72 was elevated in the dermis surrounding the microlesions after treatment; it peaked at 1 month posttreatment and became diffuse in the dermis. MPRF is a promising fractional skin resurfacing technique. The roller tip can be used with low risk in the entire treatment zone with rapid healing. An appropriate treatment regimen should be chosen to guarantee therapeutic efficacy and safety.

  10. Roller Shades with Nature Motive Supports WellbeingAmong Patients in a Heart Intensive Unit--Proof ofConcept

    Institute of Scientific and Technical Information of China (English)

    Helle Noorlind Brage

    2014-01-01

    Being a patient in a strange and unknown environment is sometimes very stressful. Research has shown that a healthpromoting environment can reduce anxiety and enhance wellbeing and views of nature can support this. This low-cost intervention wasperformed at a heart surgery intensive care unit.The aim was to use a simple method to improve the health care environment and tomonitor the experiences of patients and staf~ Two patients share the same room at the 1CU. The beds can be separated by roller shadesthat are plain grey and neutral. These were changed to new ones with nature motives. Questionnaires with fixed and open questionswere used for evaluation among patients and staff. Patients treated in an ICU seem to be aware of the surrounding environment even ifthey are severely ill. Both patients and staff stated that the roller shades with motive affected wellbeing in a positive way. An estheticalpleasing environment can contribute to wellbeing even if the effort is small and insignificant. Roller shades with nature motive might bean easy way to improve and strengthen a health promoting environment.

  11. An optimum design on rollers containing the groove with changeable inner diameter based on response surface methodology

    Directory of Open Access Journals (Sweden)

    Xi Zhao

    2016-05-01

    Full Text Available In order to realize the precision plastic forming of the revolving body component with changeable wall thickness, a kind of roller containing grooves with changeable inner diameter is put forward, as the forming mould of the technology of rolling-extrusion. Specifically, first, the arc length of the groove in the roller is designed according to the prediction on the forward slip value during the process of forming, to make accurate control of the actual length of the forming segments; then, to obtain better parameters of the roller structure, a second-order response surface model combining finite element numerical simulation and response surface methodology was put forward, taking the factor of forming uniformity as evaluation index. The result of the experiment shows that, for the formed component, not only the size can meet the needs but also each mechanical property index can be greatly improved, which verify the rationality of the forward slip model and the structural parameter of the optimum model based on the response surface methodology.

  12. Track finding efficiency in

    Energy Technology Data Exchange (ETDEWEB)

    Allmendinger, T.; Bhuyan, B.; Brown, D. N.; Choi, H.; Christ, S.; Covarelli, R.; Davier, M.; Denig, A. G.; Fritsch, M.; Hafner, A.; Kowalewski, R.; Long, O.; Lutz, A. M.; Martinelli, M.; Muller, D. R.; Nugent, I. M.; Lopes Pegna, D.; Purohit, M. V.; Prencipe, E.; Roney, J. M.; Simi, G.; Solodov, E. P.; Telnov, A. V.; Varnes, E.; Waldi, R.; Wang, W. F.; White, R. M.

    2012-12-10

    We describe several studies to measure the charged track reconstruction efficiency and asymmetry of the BaBar detector. The first two studies measure the tracking efficiency of a charged particle using τ and initial state radiation decays. The third uses the τ decays to study the asymmetry in tracking, the fourth measures the tracking efficiency for low momentum tracks, and the last measures the reconstruction efficiency of K$0\\atop{S}$ particles. The first section also examines the stability of the measurements vs. BaBar running periods.

  13. Heat loss analysis and control optimization of furnace roller for roller hearth furnace%辊底炉炉辊改进前后的热损分析和控制优化

    Institute of Scientific and Technical Information of China (English)

    李勇; 王昭东; 王国栋; 李家栋; 付天亮

    2014-01-01

    To design and control furnace roller better, heat loss law of water-cooled furnace roller which surface coat is composed of heat-resistant alloy or asbestos fibers before and after improvement was studied by mathematical models. After analyzing the problems of traditional roller hearth furnace, the improvement reason and key point were pointed out. Heat transfer models for cooling process of two kinds of rollers were established and solved with iteration planning algorithm based on Newton search. Then, the relation between water flow velocity (uw), inlet water temperature (tw-in) and roller cross section temperatures, outlet water temperature (tw-out), water temperature rise (Δtw), cooling water heat absorption (Qw) was studied. The conclusions and recommendations are mainly as follows: 1) Roller cross section temperatures, tw-out, Δtw decrease with the increase of uw. The water critical velocity (uwcv) of two kinds of furnace rolls is 0�07 m/s and 0�09 m/s respectively, and when uw is larger than uwcv, turbulent flow occurs. Considering less water scale and water treatment system cost, tw-out should be under 45℃ andΔtw should be less than 10℃. So suitable uw should be 0�4~0�8 m/s and 0�2~0�6 m/s, when cooling water is entire turbulent flow, cooling efficiency is high, andΔtw is small, above which energy consumption increase greatly and uselessly, but Qw almost remains unchanged. 2) Qw of asbestos fibers roller is small and 78% of heat-resistant alloy roller when cooling water is entire turbulent flow. Application result indicates that consumption of per ton steel is greatly reduced after the improvement and optimization control of furnace rollers, of which the reason is that production is greatly increased due to not grinding rollers, except for optimal control, fiber furnace roller heat loss is small.%采用数学模型分析辊底炉炉辊改进前后的水冷合金辊、纤维辊的热损规律。分析辊底炉存在的问题,指出炉

  14. Advanced Tracking of Vehicles

    DEFF Research Database (Denmark)

    Jensen, Christian Søndergaard; Li, K.-J.; Pakalnis, Stardas

    2005-01-01

    With the continued advances in wireless communications, geo-location technologies, and consumer electronics, it is becoming possible to accurately track the time-varying location of each vehicle in a population of vehicles. This paper reports on ongoing research that has as it objective to develop...... efficient tracking techniques. More specifically, while almost all commercially available tracking solutions simply offer time-based sampling of positions, this paper's techniques aim to offer a guaranteed tracking accuracy for each vehicle at the lowest possible costs, in terms of network traffic...... and server-side updates. This is achieved by designing, prototyping, and testing novel tracking techniques that exploit knowledge of the road network and past movement. These resulting tracking techniques are to support mobile services that rely on the existence of a central server that continuously tracks...

  15. Instrumented roll technology for the design space development of roller compaction process.

    Science.gov (United States)

    Nesarikar, Vishwas V; Vatsaraj, Nipa; Patel, Chandrakant; Early, William; Pandey, Preetanshu; Sprockel, Omar; Gao, Zhihui; Jerzewski, Robert; Miller, Ronald; Levin, Michael

    2012-04-15

    Instrumented roll technology on Alexanderwerk WP120 roller compactor was developed and utilized successfully for the measurement of normal stress on ribbon during the process. The effects of process parameters such as roll speed (4-12 rpm), feed screw speed (19-53 rpm), and hydraulic roll pressure (40-70 bar) on normal stress and ribbon density were studied using placebo and active pre-blends. The placebo blend consisted of 1:1 ratio of microcrystalline cellulose PH102 and anhydrous lactose with sodium croscarmellose, colloidal silicon dioxide, and magnesium stearate. The active pre-blends were prepared using various combinations of one active ingredient (3-17%, w/w) and lubricant (0.1-0.9%, w/w) levels with remaining excipients same as placebo. Three force transducers (load cells) were installed linearly along the width of the roll, equidistant from each other with one transducer located in the center. Normal stress values recorded by side sensors and were lower than normal stress values recorded by middle sensor and showed greater variability than middle sensor. Normal stress was found to be directly proportional to hydraulic pressure and inversely to screw to roll speed ratio. For active pre-blends, normal stress was also a function of compressibility. For placebo pre-blends, ribbon density increased as normal stress increased. For active pre-blends, in addition to normal stress, ribbon density was also a function of gap. Models developed using placebo were found to predict ribbon densities of active blends with good accuracy and the prediction error decreased as the drug concentration of active blend decreased. Effective angle of internal friction and compressibility properties of active pre blend may be used as key indicators for predicting ribbon densities of active blend using placebo ribbon density model. Feasibility of on-line prediction of ribbon density during roller compaction was demonstrated using porosity-pressure data of pre-blend and normal stress

  16. Automated Identification and Evaluation of Subtechniques in Classical-Style Roller Skiing

    Directory of Open Access Journals (Sweden)

    Yoshihisa Sakurai, Zenya Fujita, Yusuke Ishige

    2014-09-01

    Full Text Available The aims of the present study were (1 the development of an automated system for identifying classical-style ski subtechniques using angular rate sensors, and (2 the determination of the relationships among skiing velocity, ski course conditions, and ski subtechniques using a global navigation satellite system (GNSS and the developed automated identification system. In the first experiment, the performance of a male cross-country skier was used to develop an automated system for identifying classical-style ski subtechniques. In the second one, the performances of five male and five female college cross-country skiers were used to validate the developed identification system. Each subject wore inertial sensors on both wrists and both roller skis, a small video camera on the helmet, and a GNSS receiver. All subjects skied a 6,900-m roller ski course using the classical-style at their maximum speed. The adopted subtechniques were identified by the automated method based on the data obtained from the sensors, and also by visual count from a video recording of the same ski run. The results showed that the automated identification method could be definitively used to recognize various subtechniques. Specifically, the system correctly identified 9,307 subtechnique cycles out of a total of 9,444 counted visually, which indicated an accuracy of 98.5%. We also measured the skiing velocity and the course slope using the GNSS module. The data was then used to determine the subtechnique distributions as a function of the inclination and skiing velocity. It was observed that male and female skiers selected double poling below 6.7° and 5.5° uphill, respectively. In addition, male and female skiers selected diagonal stride above 0.7° and 2.5° uphill, and below 5.4 m/s and 4.5 m/s velocity, respectively. These results implied that the subtechnique distribution plot could be used to analyze the technical characteristics of each skier.

  17. Tracks: Nurses and the Tracking Network

    Centers for Disease Control (CDC) Podcasts

    2012-06-06

    This podcast highlights the utility of the National Environmental Public Health Tracking Network for nurses in a variety of work settings. It features commentary from the American Nurses Association and includes stories from a public health nurse in Massachusetts.  Created: 6/6/2012 by National Center for Environmental Health (NCEH)/Division of Environmental Hazards and Health Effects (DEHHE)/Environmental Health Tracking Branch (EHTB).   Date Released: 6/6/2012.

  18. Evaluation of HL-20 roller pump and Rotaflow centrifugal pump on perfusion quality and gaseous microemboli delivery.

    Science.gov (United States)

    Yee, Stella; Qiu, Feng; Su, Xiaowei; Rider, Alan; Kunselman, Allen R; Guan, Yulong; Undar, Akif

    2010-11-01

    The purpose of this study was to compare the HL-20 roller pump (Jostra USA, Austin, TX, USA) and Rotaflow centrifugal pump (Jostra USA) on hemodynamic energy production and gaseous microemboli (GME) delivery in a simulated neonatal cardiopulmonary bypass (CPB) circuit under nonpulsatile perfusion. This study employed a simulated model of the pediatric CPB including a Jostra HL-20 heart-lung machine (or a Rotaflow centrifugal pump), a Capiox BabyRX05 oxygenator (Terumo Corporation, Tokyo, Japan), a Capiox pediatric arterial filter (Terumo Corporation), and ¼-inch tubing. The total volume of the experimental system was 700mL (500mL for the circuit and 200mL for the pseudo neonatal patient). The hematocrit was maintained at 30% using human blood. At the beginning of each trial, a 5mL bolus of air was injected into the venous line. Both GME data and pressure values were recorded at postpump and postoxygenator sites. All the experiments were conducted under nonpulsatile perfusion at three flow rates (500, 750, and 1000mL/min) and three blood temperatures (35, 30, and 25°C). As n=6 for each setup, a total of 108 trials were done. The total number of GME increased as temperature decreased from 35°C to 25°C in the trials using the HL-20 roller pump while the opposite effect occurred when using the Rotaflow centrifugal pump. At a given temperature, total GME counts increased with increasing flow rates for both pumps. Results indicated the Rotaflow centrifugal pump delivered significantly fewer microemboli compared to the HL-20 roller pump, especially under high flow rates. Less than 10% of total microemboli were larger than 40µm in size and the majority of GME were in the 0-20µm class in all trials. Postpump total hemodynamic energy (THE) increased with increasing flow rates and decreasing temperatures in both circuits using these two pumps. The HL-20 roller pump delivered more THE than the Rotaflow centrifugal pump at all tested flow rates and temperature conditions

  19. On the Effect of Thread Turn Profile Angle of the Planetary Roller-Screw Mechanism Parts on Their Basic Parameters

    Directory of Open Access Journals (Sweden)

    D. S. Blinov

    2016-01-01

    Full Text Available One of the most important trends in mechanical engineering development is the constant improvement of load capacity of machines, mechanisms, units and parts without increasing their overall dimensions and weight. This is also true for today’s most prospective planetary rollerscrew mechanisms (PRSM converting motion from rotary to linear type. The problem of PRSM load capacity improvement deserves more attention, because these mechanisms have very high performance characteristics, which leads to problems in the choice of support devices for these mechanisms.However, for many mechanical engineering industries it is important to decrease the PRSMs weight and dimensions, or to improve their reliability and durability. This has led to finding the reserves for improving the PRSM load capacity by decreasing the thread turn profile angle, α, of PRSM threaded parts, as compared to α = 90° in traditional mechanisms. When PRSM calculation methods were developed, it was decided to use α = 90° for transforming the mechanism parts into a physical model and a design pattern. It allowed us to reduce the PRSM designing to well-known roller bearing designing based on very extensive experimental data.Proposed PRSM designs do not contradict to accepted physical models and design patterns – they just have different basic characteristics of PRSM, i.e. static and dynamic load ratings. Proposed PRSM designs with a thread turn profile angle α=70° on their parts allow to increase the load capacity by 15%, as compared to traditional PRSMs, which have threaded parts with a thread turn profile angle α = 90°. There are two factors, which can improve the PRSM load capacity. The first one is the decrease of normal force between mating thread turns of a screw and a roller with the same operational axial force. The second one is the increase of the radius of the shaped profile of a roller thread turn resulting in the expansion of the contact area pattern between the

  20. Lateral translation micro-tracking of planar micro-optic solar concentrator

    Science.gov (United States)

    Hallas, Justin M.; Karp, Jason H.; Tremblay, Eric J.; Ford, Joseph E.

    2010-08-01

    High-concentration photo-voltaic systems focus incident sunlight by hundreds of times by combining focusing lenses with accurate, dual-axis solar tracking. Conventional systems mount large optical arrays on expensive tracking pedestals to maintain normal incidence throughout the day. A recently proposed micro-optic solar concentrator utilizes a twodimensional lens array focusing into a planar slab waveguide. Localized mirrors fabricated on the waveguide surface reflect focused sunlight into guided modes which propagate towards an edge-mounted photovoltaic cell. This geometry enables a new method of solar tracking by laterally translating the waveguide with respect to the lens array to capture off-axis illumination. Using short focal length lenses, translations on the order of millimeters can efficiently collect 70° full-angle incident fields. This allows for either one or two-axis tracking systems where the small physical motion is contained within the physical footprint of a fixed solar panel. Here, we experimentally demonstrate lateral micro tracking for off-axis light collection using table-mounted components. We also present a novel tracking frame based on de-centered cams and describe a lens configuration optimized for off-axis coupling.

  1. DOUBLE TRACKS Test Site interim corrective action plan

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    1996-06-01

    The DOUBLE TRACKS site is located on Range 71 north of the Nellis Air Force Range, northwest of the Nevada Test Site (NTS). DOUBLE TRACKS was the first of four experiments that constituted Operation ROLLER COASTER. On May 15, 1963, weapons-grade plutonium and depleted uranium were dispersed using 54 kilograms of trinitrotoluene (TNT) explosive. The explosion occurred in the open, 0.3 m above the steel plate. No fission yield was detected from the test, and the total amount of plutonium deposited on the ground surface was estimated to be between 980 and 1,600 grams. The test device was composed primarily of uranium-238 and plutonium-239. The mass ratio of uranium to plutonium was 4.35. The objective of the corrective action is to reduce the potential risk to human health and the environment and to demonstrate technically viable and cost-effective excavation, transportation, and disposal. To achieve these objectives, Bechtel Nevada (BN) will remove soil with a total transuranic activity greater then 200 pCI/g, containerize the soil in ``supersacks,`` transport the filled ``supersacks`` to the NTS, and dispose of them in the Area 3 Radioactive Waste Management Site. During this interim corrective action, BN will also conduct a limited demonstration of an alternative method for excavation of radioactive near-surface soil contamination.

  2. Influence of construction interfaces on dynamic characteristics of roller compacted concrete dams

    Institute of Scientific and Technical Information of China (English)

    顾冲时; 王少伟; 包腾飞

    2015-01-01

    To study the influence of construction interfaces on dynamic characteristics of roller compacted concrete dams (RCCDs), mechanical properties of construction interfaces are firstly analyzed. Then, the viscous-spring artificial boundary (VSAB) is adopted to simulate the radiation damping of their infinite foundations, and based on the Marc software, a simplified seismic motion input method is presented by the equivalent nodal loads. Finally, based on the practical engineering of a RCC gravity dam, effects of radiation damping and construction interfaces on the dynamic characteristics of dams are investigated in detail. Analysis results show that dynamic response of the RCC gravity dam significantly reduces about 25%when the radiation damping of infinite foundation is considered. Hot interfaces and the normal cold interfaces have little influence on the dynamic response of the RCC gravity dam. However, nonlinear fracture along the cold interfaces at the dam heel will occur under the designed earthquake if the cold interfaces are combined poorly. Therefore, to avoid the fractures along the construction interfaces under the potential super earthquakes, combination quality of the RCC layers should be significantly ensured.

  3. Evaluation Standard for Safety Coefficient of Roller Compacted Concrete Dam Based on Finite Element Method

    Directory of Open Access Journals (Sweden)

    Bo Li

    2014-01-01

    Full Text Available The lack of evaluation standard for safety coefficient based on finite element method (FEM limits the wide application of FEM in roller compacted concrete dam (RCCD. In this paper, the strength reserve factor (SRF method is adopted to simulate gradual failure and possible unstable modes of RCCD system. The entropy theory and catastrophe theory are used to obtain the ultimate bearing resistance and failure criterion of the RCCD. The most dangerous sliding plane for RCCD failure is found using the Latin hypercube sampling (LHS and auxiliary analysis of partial least squares regression (PLSR. Finally a method for determining the evaluation standard of RCCD safety coefficient based on FEM is put forward using least squares support vector machines (LSSVM and particle swarm optimization (PSO. The proposed method is applied to safety coefficient analysis of the Longtan RCCD in China. The calculation shows that RCCD failure is closely related to RCCD interface strength, and the Longtan RCCD is safe in the design condition. Considering RCCD failure characteristic and combining the advantages of several excellent algorithms, the proposed method determines the evaluation standard for safety coefficient of RCCD based on FEM for the first time and can be popularized to any RCCD.

  4. Adaptive Redundant Lifting Wavelet Transform Based on Fitting for Fault Feature Extraction of Roller Bearings

    Directory of Open Access Journals (Sweden)

    Huaqing Wang

    2012-03-01

    Full Text Available A least square method based on data fitting is proposed to construct a new lifting wavelet, together with the nonlinear idea and redundant algorithm, the adaptive redundant lifting transform based on fitting is firstly stated in this paper. By variable combination selections of basis function, sample number and dimension of basis function, a total of nine wavelets with different characteristics are constructed, which are respectively adopted to perform redundant lifting wavelet transforms on low-frequency approximate signals at each layer. Then the normalized lP norms of the new node-signal obtained through decomposition are calculated to adaptively determine the optimal wavelet for the decomposed approximate signal. Next, the original signal is taken for subsection power spectrum analysis to choose the node-signal for single branch reconstruction and demodulation. Experiment signals and engineering signals are respectively used to verify the above method and the results show that bearing faults can be diagnosed more effectively by the method presented here than by both spectrum analysis and demodulation analysis. Meanwhile, compared with the symmetrical wavelets constructed with Lagrange interpolation algorithm, the asymmetrical wavelets constructed based on data fitting are more suitable in feature extraction of fault signal of roller bearings.

  5. Microstructural and Chemical Characterization of the Tribolayer Formation in Highly Loaded Cylindrical Roller Thrust Bearings

    Directory of Open Access Journals (Sweden)

    Carsten Gachot

    2016-06-01

    Full Text Available Zinc dithiophosphates (ZDDP have been widely applied in automobile industry for over 70 years as a lubricant additive for wear protection. Tribolayers have been described as blue- and brown-colored layers on surfaces observed by microscopical observation or even bare eye presumably as a consequence of layer thickness or chemical composition. However, the reaction pathways of ZDDP tribolayers are still not yet fully understood. In the present study, the difference between the blue- and brown-colored tribolayers has been revealed by high resolution methods in cylindrical roller thrust bearings at relatively high contact pressures of around 1.92 GPa. After running a FE8 standard bearing test with a normal load of 80 kN and a temperature of 60 °C, said tribolayers could be identified on the bearing surfaces. By using Raman spectroscopy, it could be shown that the blue-colored layers are enriched by FeS and ZnS whereas the brown-colored layers show a significant amount of Fe3O4. This is an interesting finding as it clearly shows a correlation between the color appearance of the films and the chemical composition besides potential film thickness variations. Finally, transmission electron microscopy verified the amorphous nature of the formed tribolayer which is in a good agreement with literature.

  6. Dynamics of vehicle-pavement coupled system based on a revised flexible roller contact tire model

    Institute of Scientific and Technical Information of China (English)

    2009-01-01

    A revised flexible roller contact tire model (RFRC tire model) is proposed, which considers not only the geometric and flexible filtering effect, but also tire damping and pavement displacement. A vehi- cle-pavement coupled system is modeled as a two DOF oscillator moving along a simply supported beam on a linear viscoelastic foundation. By using the Galerkin’s and Direct Integral method, dynamical responses of the vehicle-pavement coupled system are obtained based on the RFRC tire model and the traditional single point contact tire model (SPC tire model). The simulation results are compared with test data and the validity of the proposed RFRC tire model is verified. Differences between the two models are also investigated. It is found that the dynamical behaviors for both models agree with each other quite well when road surface roughness is a long harmonic wave. On the other hand, they are different under short harmonic wave or impulse road excitation. Thus the RFRC tire model should be used to compute the tire force and investigate dynamical responses of vehicle and pavement.

  7. Riding the research roller coaster: what went right, what went wrong?

    Science.gov (United States)

    Netta-Turner, Denise; Bucher, Linda; Dixon, Lois; Layton, Norma Jean

    2008-01-01

    Evidence-based practice drives nursing procedures and standards of care. Supporting practice with valid research can be a challenge. After identifying a knowledge- and problem-focused trigger, a group of WOC nurses began a research journey. Our purpose was to determine the effectiveness of the rectal trumpet compared to the fecal collector in maintaining skin integrity in patients with fecal incontinence. The methodology included a convenience sample of 100 patients randomized to rectal trumpet or fecal collector versus standard care. Data were collected on signs of increased skin breakdown or healing, stool leakage around device, dislodgement, and discomfort from device. This article will reveal our journey in conducting this clinical research. After many challenges, the study was terminated, but the experiences and lessons learned during our efforts were invaluable. Even well-planned studies can encounter problems that prevent completion. It is important to evaluate these problems so that lessons can be learned and shared. This is our roller coaster ride in the research world.

  8. Roller Coaster Scanning reveals spontaneous triggering of dendritic spikes in CA1 interneurons.

    Science.gov (United States)

    Katona, Gergely; Kaszás, Attila; Turi, Gergely F; Hájos, Norbert; Tamás, Gábor; Vizi, E Sylvester; Rózsa, Balázs

    2011-02-01

    Inhibitory interneurons are considered to be the controlling units of neural networks, despite their sparse number and unique morphological characteristics compared with excitatory pyramidal cells. Although pyramidal cell dendrites have been shown to display local regenerative events--dendritic spikes (dSpikes)--evoked by artificially patterned stimulation of synaptic inputs, no such studies exist for interneurons or for spontaneous events. In addition, imaging techniques have yet to attain the required spatial and temporal resolution for the detection of spontaneously occurring events that trigger dSpikes. Here we describe a high-resolution 3D two-photon laser scanning method (Roller Coaster Scanning) capable of imaging long dendritic segments resolving individual spines and inputs with a temporal resolution of a few milliseconds. By using this technique, we found that local, NMDA receptor-dependent dSpikes can be observed in hippocampal CA1 stratum radiatum interneurons during spontaneous network activities in vitro. These NMDA spikes appear when approximately 10 spatially clustered inputs arrive synchronously and trigger supralinear integration in dynamic interaction zones. In contrast to the one-to-one relationship between computational subunits and dendritic branches described in pyramidal cells, here we show that interneurons have relatively small (∼14 μm) sliding interaction zones. Our data suggest a unique principle as to how interneurons integrate synaptic information by local dSpikes.

  9. Determination of the Nip Angle in Roller Compactors With Serrated Rolls.

    Science.gov (United States)

    Tan, Bernice Mei Jin; Chan, Lai Wah; Heng, Paul Wan Sia

    2016-06-01

    In roller compaction, the nip angle defines the critical transition interface between the slip and nip regions which is used to model material densification behavior and the properties of compacted ribbons. Current methods to determine the nip angle require either sophisticated instrumentation on smooth rolls or input parameters that are difficult to obtain experimentally. In this study, a practical method to determine nip angles for serrated rolls was developed based on mass balance considerations established around the nip region. Experimental input relating to roll geometry, powder density, and mass output from the compactor were required and they could be obtained reliably. The calculated nip angles were validated against those obtained from physical measurements during actual roll compaction. These nip angles were in agreement for various powder formulations containing plastic and brittle materials. The nip angles ranged from 4° to 12° and decreased significantly when the proportion of brittle material increased. Nip angles were also calculated using the widely used Johanson model. However, wall friction measurement on serrated roll surfaces could be impractical. The Johanson model-derived nip angles could differ by 3°-8° just by altering the roughness of the reference wall and this had compromised their reliability.

  10. Performance Improvement of Ensemble Empirical Mode Decomposition for Roller Bearings Damage Detection

    Directory of Open Access Journals (Sweden)

    Ali Akbar Tabrizi

    2015-01-01

    Full Text Available Ensemble empirical mode decomposition (EEMD is a noise assisted method widely used for roller bearing damage detection. However, to successfully handle this technique still remains a great challenge: identification of two effective parameters (the amplitude of added noise and the number of ensemble trials, which affect the performances of the EEMD. Although a number of algorithms or values have been proposed, there is no robust guide to select optimal amplitude and the ensemble trial number yet, especially for early damage detection. In this study, a reliable method is proposed to determine the suitable amplitude and the proper number of trials is investigated as well. It is shown that the proposed method (performance improved EEMD achieves higher damage detection success rate and creates larger Margin than the original algorithm. It leads to a substantially low trial numbers required to achieve perfect labelling of samples; in turn this fact leads to considerably less computational cost. The number of real vibration signals is analysed to verify effectiveness and robustness of the proposed method in discriminating and separating the faulty conditions.

  11. A novel method for estimating solid fraction of roller-compacted ribbons.

    Science.gov (United States)

    Nkansah, Paul; Wu, Sy-Juen; Sobotka, Stephanie; Yamamoto, Ken; Shao, Zezhi J

    2008-02-01

    A simple method has been developed to estimate solid fraction or relative density of compacts using the weight of ribbons produced during roller compaction. The method provides an alternative to the commonly used dimensional measurement, especially for formulations not amenable to forming quality ribbons. Surface texture of the compaction rolls has been taken into consideration in our mathematical treatment along with correction for ribbon relaxation. Ribbon relaxation occurring upon ribbon exiting the compaction zone is estimated using roll geometry, roll gap, and ribbon thickness. Detailed experimental runs have been carried out to confirm the validity of the proposed theory. The predicted solid fraction was found comparable to that from actual dimensional measurement by caliper. In the case of the microcrystalline cellulose/dicalcium phosphate one:one formulation, the predicted solid fraction had an error sum of squares (SSE) of 2.64E-03 when compared to the dimensional method. When relaxation was included, the SSE decreased by four folds. Similarly, for the microcrystalline cellulose/lactose monohydrate 2:1 formulation, the SSE decreased twelfth folds when relaxation was taken into consideration. These results further confirm the utility of the proposed throughput method for estimating the solid fraction of ribbons.

  12. Determination of interference fit value on entire roller embedded shapemeter roll

    Institute of Scientific and Technical Information of China (English)

    吴海淼; 刘宏民; 于丙强; 杨利坡

    2014-01-01

    For entire roller embedded shapemeter roll, the relationship between the value of interference fit and the sensor pre-pressure, and the pressure transfer performance of shapemeter roll were analyzed by elasticity theory during the cold reversible rolling process. Considering the influence of strip temperature on the interference fit, the distributions of contact pressure of the framework’s top surface and the sensor pre-pressure on different values of interference fit were analyzed by the finite element technology. The results show that the contact pressure of the framework’s top surface and the sensor pre-pressure increase with the increase of the value of interference fit. When the value of interference fit is between 0.05 mm and 0.09 mm, roll body’s inner hole surface, the framework and pressure magnetic sensitive component don’t separate from each other, and the sensor works in the linear segment of characteristic curve, so the normal operation of shapemeter roll is guaranteed.

  13. An investigation of cam-roller mechanism applied in sphere cam engine

    Institute of Scientific and Technical Information of China (English)

    张雷; 潘存云; 徐小军; 徐海军; 张正洲

    2016-01-01

    As an alternative power source for hybrid electrical vehicle(HEV), electric generating system(EGS) driven by sphere cam engine(SCE) is said to own higher power density and integration. In this work, the structure and working principle of EGS were introduced, based on which the advantages of EGS were displayed. The profile of sphere cam was achieved after the desired motion of piston was given. After establishing the dynamic model of power transmission mechanism, the characteristics of cam-roller mechanism were studied. The results show that the optimal cam profile of SCE is a sinusoid curve which has two peaks and two valleys and a mean pressure angle of 47.19°. Because of the special cam shape, the trace of end surface center of piston is an eight-shape curve on a specific sphere surface. SCE running at speed of 3000 r/min can generate the power of 33.81 kW, which could satisfy the need of HEVs. However, the force between cylinder and piston skirt caused by Coriolis acceleration can reach up to 1182 N, which leads to serious wear between cylinder liner and piston skirt and may shorten the lifespan of SCE.

  14. Thickness Analysis of Stone Mastic Asphalt (SMA Slab Compacted Using a Newly Developed Roller Compactor

    Directory of Open Access Journals (Sweden)

    R. Muniandy

    2007-01-01

    Full Text Available Pavement mix design procedures and specifications are usually derived from laboratory experiments. Therefore, laboratory experiments should be able to simulate to a high degree the conditions in the field, especially in term of compaction procedures. Based on literature reviews and analysis of past studies, it can be concluded that there are no exact method for laboratory compaction that can simulate field compaction procedures. Turamesin, a newly developed laboratory compaction device has been designed to provide a solution to the problem of producing laboratory specimens which are representative of materials laid and compacted in the field. This study reports on the evaluation of the thickness of the compacted slabs and analysis of the consistency of the measured parameter. A total of 15 slabs from three different types of asphalt binders, namely Grade 60/70, Grade PG76 and Grade 80/100 were prepared, measured and analyzed. Based on statistical analysis conducted, the compacted slabs were found to have an average area of 590 mm of length by 500 mm of width and thickness ranging from 60 mm to 68 mm. The compacted slabs were found to have problems in terms of the difference in thickness between left-side and right-side of the slab that occurred due to unequal load distribution from the roller compactor. The results obtained from this study will lead to development of Turamesin as an improved laboratory compaction device.

  15. Pediatric ECMO outcomes: comparison of centrifugal versus roller blood pumps using propensity score matching.

    Science.gov (United States)

    Barrett, Cindy S; Jaggers, James J; Cook, E Francis; Graham, Dionne A; Yarlagadda, Vasmi V; Teele, Sarah A; Almond, Christopher S; Bratton, Susan L; Seeger, John D; Dalton, Heidi J; Rycus, Peter T; Laussen, Peter C; Thiagarajan, Ravi R

    2013-01-01

    Centrifugal blood pumps are being increasingly utilized in children supported with extracorporeal membrane oxygenation (ECMO). Our aim was to determine if survival and ECMO-related morbidities in children supported with venoarterial (VA) ECMO differed by blood pump type.Children aged less than 18 years who underwent VA ECMO support from 2007 to 2009 and reported to the Extracorporeal Life Support Organization registry were propensity score matched (Greedy 1:1 matching) using pre-ECMO characteristics.A total of 2,656 (centrifugal = 2,231, roller = 425) patients were identified and 548 patients (274 per pump type) were included in the propensity score-matched cohort. Children supported with centrifugal pumps had increased odds of hemolysis (odds ratio [OR], 4.03 95% confidence interval [CI], 2.37-6.87), hyperbilirubinemia (OR, 5.48; 95% CI, 2.62-11.49), need for inotropic support during ECMO (OR, 1.54; 95% CI, 1.09-2.17), metabolic alkalosis (blood pH > 7.6) during ECMO (OR, 3.13; 95% CI, 1.49-6.54), and acute renal failure (OR, 1.61; 95% CI, 1.10-2.39). Survival to hospital discharge did not differ by pump type.In a propensity score-matched cohort of pediatric ECMO patients, children supported with centrifugal pumps had increased odds of ECMO-related complications. There was no difference in survival between groups.

  16. The physiological and biomechanical contributions of poling to roller ski skating.

    Science.gov (United States)

    Sandbakk, Øyvind; Ettema, Gertjan; Holmberg, Hans-Christer

    2013-08-01

    Poling is considered to make a significant contribution to cross-country skiing with the skating technique. To better understand this contribution, the current investigation compared roller ski skating on a treadmill with the so-called G3 skating technique with (G3-P) and without poling (G3-NP). Seven male elite skiers performed 5-min submaximal tests at 8, 12, and 15 km h(-1), as well as an incremental test to exhaustion with both techniques on a 5 % incline. Ventilatory variables were assessed by open-circuit indirect calorimetry and three-dimensional kinematics analyzed using the Qualisys Pro Reflex system. G3-P was associated with approximately 15 % higher peak velocity and 10 % higher peak oxygen uptake than G3-NP in the incremental test (both P ski gliding and swing phases were longer and the angle between the skis smaller with G3-P (both P ski skating, specifically by enhancing peak oxygen uptake, skiing efficiency and associated biomechanical variables.

  17. Dynamics of vehicle-pavement coupled system based on a revised flexible roller contact tire model

    Institute of Scientific and Technical Information of China (English)

    YANG ShaoPu; LI ShaoHua; LU YongJie

    2009-01-01

    A revised flexible roller contact tire model (RFRC tire model) is proposed, which considers not only the geometric and flexible filtering effect, but also tire damping and pavement displacement. A vehi-cle-pavement coupled system is modeled as a two DOF oscillator moving along a simply supported beam on a linear viscoelastic foundation. By using the Galerkin's and Direct Integral method, dynamical responses of the vehicle-pavement coupled system are obtained based on the RFRC tire model and the traditional single point contact tire model (SPC tire model). The simulation results are compared with test data and the validity of the proposed RFRC tire model is verified. Differences between the two models are also investigated. It is found that the dynamical behaviors for both models agree with each other quite well when road surface roughness is a long harmonic wave. On the other hand, they are different under short harmonic wave or impulse road excitation. Thus the RFRC tire model should be used to compute the tire force and investigate dynamical responses of vehicle and pavement.

  18. Reactive self-tracking solar concentrators: concept, design, and initial materials characterization.

    Science.gov (United States)

    Baker, Katherine A; Karp, Jason H; Tremblay, Eric J; Hallas, Justin M; Ford, Joseph E

    2012-03-10

    Étendue limits angular acceptance of high-concentration photovoltaic systems and imposes precise two-axis mechanical tracking. We show how a planar micro-optic solar concentrator incorporating a waveguide cladding with a nonlinear optical response to sunlight can reduce mechanical tracking requirements. Optical system designs quantify the required response: a large, slow, and localized increase in index of refraction. We describe one candidate materials system: a suspension of high-index particles in a low-index fluid combined with a localized space-charge field to increase particle density and average index. Preliminary experiments demonstrate an index change of aqueous polystyrene nanoparticles in response to a low voltage signal and imply larger responses with optimized nanofluidic materials.

  19. On Not Losing Track

    OpenAIRE

    Washburn, A.R.

    1990-01-01

    IEEE Transactions on Automatic Control, Vol. 35, 1990, pp. 852-855. This paper uses tracking time as an explicit objective in designing tracking algorithms that function in clutter. Implications of using "time to the first mistake" as a measure of tracking time are explored. An optimal tracker is derived for a special circukstance where there is clutter, but no measurement error, and is compared to a tracker based on the Maximum Likelihood principle.

  20. The effect of extrusion and drying on roller techniques concerning the rheological characteristics of rice-, corn-, sweet potato-, bean- and cassava root- and leaf- based composite flour

    Directory of Open Access Journals (Sweden)

    Johanna Aristizábal Galvis

    2013-04-01

    Full Text Available Promoting food security in Latin-America and the Caribbean is directly related to agricultural products. The region faces a food crisis which has reduced large population groups’ access to food. This work contributes to the study of obtaining precooked composite flour made from biofortified crops using protein, vitamin A and/or minerals. This study evaluated the effect of precooked flour’s composition and precooking on its solubility in water, water absorption capacity, consistency and viscosity; such flour was obtained by extrusion and drying on rollers. The composite flours were obtained from cassava roots, sweet potato tubers, corn, rice and bean grains and cassava leaves. Four composite flours were formulated taking four- to six-year-old children’s daily nutrient requirements (protein, iron, zinc and beta-carotenes as a basis. The extruder was operated at 90ºC, 300 rpm screw rotation speed, 17.64 g/min feed flow, with 30% moisture mixture. The dryer rollers were operated at 4 rpm roller rotation speed, 90ºC surface temperature and 1 mm separation between rollers. It was determined that flour dried on rollers led to more complete cooking and modified starch granule structure than precooking by extrusion, thereby producing flour having greater solubility in water, less water absorption, higher consistency and smaller viscosity, comparable to that of pattern flour.

  1. DCS Budget Tracking System

    Data.gov (United States)

    Social Security Administration — DCS Budget Tracking System database contains budget information for the Information Technology budget and the 'Other Objects' budget. This data allows for monitoring...

  2. CWI at TREC 2012, KBA track and Session Track

    NARCIS (Netherlands)

    Araújo, S.; Boscarino, C.; Gebremeskel, G.G.; He, J.; Vries, A.P. de; Voorhees, E.M.; Buckland, L. P.

    2013-01-01

    We participated in two tracks: Knowledge Base Acceleration (KBA) Track and Session Track. In the KBA track, we focused on experi- menting with different approaches as it is the first time the track is launched. We experimented with supervised and unsupervised re- trieval models. Our supervised appro

  3. CWI at TREC 2012, KBA track and Session Track

    NARCIS (Netherlands)

    S. Araújo (Samur); C. Boscarino (Corrado); G.G. Gebremeskel (Gebre); J. He (Jiyin); A.P. de Vries (Arjen)

    2013-01-01

    htmlabstractWe participated in two tracks: Knowledge Base Acceleration (KBA) Track and Session Track. In the KBA track, we focused on experi- menting with different approaches as it is the first time the track is launched. We experimented with supervised and unsupervised re- trieval models. Our supe

  4. 高速铁路道岔辊轮的国产化研制%Domestic Development of Roller for High Speed Railway Turnout

    Institute of Scientific and Technical Information of China (English)

    刘皓

    2014-01-01

    在总结进口客专道岔用辊轮使用经验的基础上,介绍了国产化辊轮的结构设计、制造工艺研究、试制及试用测试等工作;通过检测和试用验证,国产化辊轮能够替代进口产品,同时满足高速铁路道岔使用的要求。%Based on the experience of imported roller for the turnout of passenger dedicated line,this article introduces the structural design,research on manufacturing process,trial production and trial test of domestic roller;through test and trial verification,it is found that domestic roller can be used to replace the imported products and meet the requirements of high speed railway turnout.

  5. On the Wrong Track?

    Science.gov (United States)

    Gursky, Daniel

    1990-01-01

    Discusses problems with student tracking. Although supporters consider tracking the best way for teachers to handle classroom diversity, many minorities say that it condemns their children to an inferior education. Studies show that heterogeneous classes benefit all students if the teachers adopt flexible instructional methods to handle the…

  6. Can Tracking Improve Learning?

    Science.gov (United States)

    Duflo, Esther; Dupas, Pascaline; Kremer, Michael

    2009-01-01

    Tracking students into different classrooms according to their prior academic performance is controversial among both scholars and policymakers. If teachers find it easier to teach a homogeneous group of students, tracking could enhance school effectiveness and raise test scores of both low- and high-ability students. If students benefit from…

  7. Can Tracking Improve Learning?

    Science.gov (United States)

    Duflo, Esther; Dupas, Pascaline; Kremer, Michael

    2009-01-01

    Tracking students into different classrooms according to their prior academic performance is controversial among both scholars and policymakers. If teachers find it easier to teach a homogeneous group of students, tracking could enhance school effectiveness and raise test scores of both low- and high-ability students. If students benefit from…

  8. Large scale tracking algorithms

    Energy Technology Data Exchange (ETDEWEB)

    Hansen, Ross L. [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States); Love, Joshua Alan [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States); Melgaard, David Kennett [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States); Karelitz, David B. [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States); Pitts, Todd Alan [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States); Zollweg, Joshua David [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States); Anderson, Dylan Z. [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States); Nandy, Prabal [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States); Whitlow, Gary L. [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States); Bender, Daniel A. [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States); Byrne, Raymond Harry [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States)

    2015-01-01

    Low signal-to-noise data processing algorithms for improved detection, tracking, discrimination and situational threat assessment are a key research challenge. As sensor technologies progress, the number of pixels will increase signi cantly. This will result in increased resolution, which could improve object discrimination, but unfortunately, will also result in a significant increase in the number of potential targets to track. Many tracking techniques, like multi-hypothesis trackers, suffer from a combinatorial explosion as the number of potential targets increase. As the resolution increases, the phenomenology applied towards detection algorithms also changes. For low resolution sensors, "blob" tracking is the norm. For higher resolution data, additional information may be employed in the detection and classfication steps. The most challenging scenarios are those where the targets cannot be fully resolved, yet must be tracked and distinguished for neighboring closely spaced objects. Tracking vehicles in an urban environment is an example of such a challenging scenario. This report evaluates several potential tracking algorithms for large-scale tracking in an urban environment.

  9. Incentives from Curriculum Tracking

    Science.gov (United States)

    Koerselman, Kristian

    2013-01-01

    Curriculum tracking creates incentives in the years before its start, and we should therefore expect test scores to be higher during those years. I find robust evidence for incentive effects of tracking in the UK based on the UK comprehensive school reform. Results from the Swedish comprehensive school reform are inconclusive. Internationally, I…

  10. Bewegingsvolgsysteem = Monitor tracking system

    NARCIS (Netherlands)

    Slycke, Per Johan; Veltink, Petrus Hermanus; Roetenberg, Daniel

    2006-01-01

    A motion tracking system for tracking an object composed of object parts in a three-dimensional space. The system comprises a number of magnetic field transmitters; a number of field receivers for receiving the magnetic fields of the field transmitters; a number of inertial measurement units for rec

  11. Bewegingsvolgsysteem = Monitor tracking system

    NARCIS (Netherlands)

    Slycke, Per Johan; Veltink, Petrus Hermanus; Roetenberg, Daniel

    2007-01-01

    A motion tracking system for tracking an object composed of object parts in a three-dimensional space. The system comprises a number of magnetic field transmitters; a number of field receivers for receiving the magnetic fields of the field transmitters; a number of inertial measurement units for rec

  12. Eye-Tracking

    Directory of Open Access Journals (Sweden)

    Gabriela GROSSECK

    2006-01-01

    Full Text Available Eye-tracking: one of the newest and most efficient methods of improving on-line marketing communication is called eye-tracking. Marketers have borrowed this technique, usually used in psychological and medical research, in order to study web users with the help of a video camera incorporated in the monitor.

  13. Large scale tracking algorithms.

    Energy Technology Data Exchange (ETDEWEB)

    Hansen, Ross L.; Love, Joshua Alan; Melgaard, David Kennett; Karelitz, David B.; Pitts, Todd Alan; Zollweg, Joshua David; Anderson, Dylan Z.; Nandy, Prabal; Whitlow, Gary L.; Bender, Daniel A.; Byrne, Raymond Harry

    2015-01-01

    Low signal-to-noise data processing algorithms for improved detection, tracking, discrimination and situational threat assessment are a key research challenge. As sensor technologies progress, the number of pixels will increase signi cantly. This will result in increased resolution, which could improve object discrimination, but unfortunately, will also result in a significant increase in the number of potential targets to track. Many tracking techniques, like multi-hypothesis trackers, suffer from a combinatorial explosion as the number of potential targets increase. As the resolution increases, the phenomenology applied towards detection algorithms also changes. For low resolution sensors, "blob" tracking is the norm. For higher resolution data, additional information may be employed in the detection and classfication steps. The most challenging scenarios are those where the targets cannot be fully resolved, yet must be tracked and distinguished for neighboring closely spaced objects. Tracking vehicles in an urban environment is an example of such a challenging scenario. This report evaluates several potential tracking algorithms for large-scale tracking in an urban environment.

  14. Corrective Action Plan for Corrective Action Unit 407: Roller Coaster RADSAFE Area, Tonopah Test Range, Nevada

    Energy Technology Data Exchange (ETDEWEB)

    T. M. Fitzmaurice

    2000-05-01

    This Corrective Action Plan (CAP) has been prepared for the Roller Coaster RADSAFE Area Corrective Action Unit 407 in accordance with the Federal Facility and Consent Order (Nevada Division of Environmental Protection [NDEP] et al., 1996). This CAP provides the methodology for implementing the approved Corrective Action Alternative as listed in the Corrective Action Decision Document (U.S. Department of Energy, Nevada Operations Office, 1999). The RCRSA was used during May and June of 1963 to decontaminate vehicles, equipment, and personnel from the Clean Slate tests. The Constituents of Concern (COCs) identified during the site characterization include plutonium, uranium, and americium. No other COCS were identified. The following closure actions will be implemented under this plan: (1) Remove and dispose of surface soils which are over three times background for the area. Soils identified for removal will be disposed of at an approved disposal facility. Excavated areas will be backfilled with clean borrow soil fi-om a nearby location. (2) An engineered cover will be constructed over the waste disposal pit area where subsurface COCS will remain. (3) Upon completion of the closure and approval of the Closure Report by NDEP, administrative controls, use restrictions, and site postings will be used to prevent intrusive activities at the site. Barbed wire fencing will be installed along the perimeter of this unit. Post closure monitoring will consist of site inspections to determine the condition of the engineered cover. Any identified maintenance and repair requirements will be remedied within 90 working days of discovery and documented in writing at the time of repair. Results of all inspections/repairs for a given year will be addressed in a single report submitted annually to the NDEP.

  15. Importance of using roller compacted concrete in techno-economic investigation and design of small dams

    Science.gov (United States)

    Rouissat, Bouchrit; Smail, N.; Zenagui, S.

    2017-07-01

    In recent years, and under constraints caused by persistent drought, Algeria has launched a new mobilization strategy for surface water resources from small and medium dams. However, by making a review of the studies and achievements of twenty small dams in the west of Algeria, some deficiencies appeared. In addition to reservoir siltation assessment, operation spillways have been the major constraint on the reliability of these types of dams. The objective of this paper is to use the roller compacted concrete (RCC) for small dams' design for the benefit it offers and its ability to incorporate spillways. The development of this reflection was applied to the Khneg Azir earth dam situated in southwest of Algeria. Its uncontrolled lateral spillway has registered significant damage following the flood of October 2005, amounted, at that time, to more than 100 million Algerian dinars (1 million US Dollars). The present research encompasses a technical and economical comparative analysis concerning multiple criteria dam design types coupled with the conjugation of the spillways. Thus, on the basis of financial estimates calculated for all design types, the variant RCC remains competitive with that of the earth dam's spillway isolated (Less than 40% of the cost). To assess the mechanical behavior of the foundations for both types of dams, (earth and RCC dams), numerical modeling has been undertaken, according to the comparative analysis of deformations in the foundations. Analysis of deformations showed that the average foundation deformations was between (0.052-0.85) m for earth dam and (0.023-0.373) m for RCC dam. These economical and technical considerations open up important prospects for the use of RCC in the design of small dams.

  16. E2F Transcription Factors Control the Roller Coaster Ride of Cell Cycle Gene Expression.

    Science.gov (United States)

    Thurlings, Ingrid; de Bruin, Alain

    2016-01-01

    Initially, the E2F transcription factor was discovered as a factor able to bind the adenovirus E2 promoter and activate viral genes. Afterwards it was shown that E2F also binds to promoters of nonviral genes such as C-MYC and DHFR, which were already known at that time to be important for cell growth and DNA metabolism, respectively. These findings provided the first clues that the E2F transcription factor might be an important regulator of the cell cycle. Since this initial discovery in 1987, several additional E2F family members have been identified, and more than 100 targets genes have been shown to be directly regulated by E2Fs, the majority of these are important for controlling the cell cycle. The progression of a cell through the cell cycle is accompanied with the increased expression of a specific set of genes during one phase of the cell cycle and the decrease of the same set of genes during a later phase of the cell cycle. This roller coaster ride, or oscillation, of gene expression is essential for the proper progression through the cell cycle to allow accurate DNA replication and cell division. The E2F transcription factors have been shown to be critical for the temporal expression of the oscillating cell cycle genes. This review will focus on how the oscillation of E2Fs and their targets is regulated by transcriptional, post-transcriptional and post-translational mechanism in mammals, yeast, flies, and worms. Furthermore, we will discuss the functional impact of E2Fs on the cell cycle progression and outline the consequences when E2F expression is disturbed.

  17. Sparse Hashing Tracking.

    Science.gov (United States)

    Zhang, Lihe; Lu, Huchuan; Du, Dandan; Liu, Luning

    2016-02-01

    In this paper, we propose a novel tracking framework based on a sparse and discriminative hashing method. Different from the previous work, we treat object tracking as an approximate nearest neighbor searching process in a binary space. Using the hash functions, the target templates and the candidates can be projected into the Hamming space, facilitating the distance calculation and tracking efficiency. First, we integrate both the inter-class and intra-class information to train multiple hash functions for better classification, while most classifiers in previous tracking methods usually neglect the inter-class correlation, which may cause the inaccuracy. Then, we introduce sparsity into the hash coefficient vectors for dynamic feature selection, which is crucial to select the discriminative and stable features to adapt to visual variations during the tracking process. Extensive experiments on various challenging sequences show that the proposed algorithm performs favorably against the state-of-the-art methods.

  18. TRACKED VEHICLE Rev 75

    Energy Technology Data Exchange (ETDEWEB)

    2007-05-08

    Revision 75 of the Tracked Vehicle software is a soft real-time simulation of a differentially steered, tracked mobile robot, which, because of the track flippers, resembles the iRobot PackBot (http://www.irobot.com/). Open source libraries are used for the physics engine (http://www.ode.org/), the display and user interface (http://www.mathies.com/cpw/), and the program command line and configuration file parameters (http://www.boost.org/). The simulation can be controlled by a USB joystick or the keyboard. The configuration file contains demonstration model parameters of no particular vehicle. This simulation can be used as a starting point for those doing tracked vehicle simulations. This simulation software is essentially a research tool which can be modified and adapted for certain types of tracked vehicle research. An open source license allows an individual researchers to tailor the code to their specific research needs.

  19. Working condition: A key factor in increasing occupational hazard among bidi rollers: A population health research with respect to DNA damage

    Directory of Open Access Journals (Sweden)

    Poonam Shukla

    2011-01-01

    Full Text Available The present investigation was undertaken to study the role of working conditions in occupational hazards among bidi rollers occupationally exposed to tobacco dust with reference to DNA damage in peripheral blood lymphocytes. Initially, biomonitoring was conducted by estimating urinary thioether to detect the extent of xenobiotic exposure, and genotoxicity was evaluated by assessing DNA damage and micronucleus frequency in buccal epithelial cells in female bidi rollers occupationally exposed to bidi tobacco dust. Student′s t-test was used to test the significance between the means. Results showed a significant increase in urinary thioether level in during-shift urine samples as compared to pre-shift samples, which indicated exposure of bidi rollers to xenobiotic compounds. A significant increase in DNA damage was observed in the rollers working in confined environment as compared to those who worked in open and mixed kind of working conditions. Keeping in view the adverse effects of tobacco inhalation on the genotoxic effects in bidi rollers as an occupational hazard and in order to minimize the hazardous effects, it is recommended that masks should be worn by the bidi rollers during work to minimize inhalation of tobacco dust. Gloves should be worn particularly if there are bruises etc. in the palm. To minimize the absorption through eyes, covered glasses should be worn. The entire process of bidi rolling may be done preferably under well ventilated conditions. Due care to be taken to sit in the direction facing the direction of wind to avoid inhalation of blown away tobacco dust.

  20. A Slope Roller on A New Conveyer%一种新型传动结构的斜坡辊道

    Institute of Scientific and Technical Information of China (English)

    万志波; 王艳芹; 要路岗; 印文忠; 刘金锁

    2012-01-01

    浮法玻璃厂联合车间受工艺限制,往往将2楼熔制成形车间和1楼包装车间用斜坡辊道连接起来。而2楼与斜坡之间衔接的凸弧辊道、1楼与斜坡之间衔接的凹弧辊道,其结构形式往往成为设计及安装调试的难点。传统的弧段结构采用锥齿轮箱和同步带传动结构,与当前主流的通轴弧齿锥齿轮结构相比较为落后。本文对浮法玻璃车间斜坡辊道结构进行详细阐述,并提出了一种新的凸、凹弧辊道的传动结构。%The melting and forming workshop on the 2no floor was usually connected with the packing workshop on the 1^st floor by a slope roller due to the limit of process in the combined workshop of float glass factory. The difficulty for design and installation is the convex arc roller which connects between 2nd floor and slope and the concave arc roller which links the 1^st floor with slope roller. The traditional transition section structure includes the bevel gear box and the synchronous belt transmission, which lags behind the current mainstream of the bevel gear shaft structure.. This paper expounds the flat glass workshop slope roller structure, and puts forward a new kind of convex arc and concave arc roller drive structure.

  1. Persistent Aerial Tracking

    KAUST Repository

    Mueller, Matthias

    2016-04-13

    In this thesis, we propose a new aerial video dataset and benchmark for low altitude UAV target tracking, as well as, a photo-realistic UAV simulator that can be coupled with tracking methods. Our benchmark provides the rst evaluation of many state of-the-art and popular trackers on 123 new and fully annotated HD video sequences captured from a low-altitude aerial perspective. Among the compared trackers, we determine which ones are the most suitable for UAV tracking both in terms of tracking accuracy and run-time. We also present a simulator that can be used to evaluate tracking algorithms in real-time scenarios before they are deployed on a UAV "in the field", as well as, generate synthetic but photo-realistic tracking datasets with free ground truth annotations to easily extend existing real-world datasets. Both the benchmark and simulator will be made publicly available to the vision community to further research in the area of object tracking from UAVs. Additionally, we propose a persistent, robust and autonomous object tracking system for unmanned aerial vehicles (UAVs) called Persistent Aerial Tracking (PAT). A computer vision and control strategy is applied to a diverse set of moving objects (e.g. humans, animals, cars, boats, etc.) integrating multiple UAVs with a stabilized RGB camera. A novel strategy is employed to successfully track objects over a long period, by \\'handing over the camera\\' from one UAV to another. We integrate the complete system into an off-the-shelf UAV, and obtain promising results showing the robustness of our solution in real-world aerial scenarios.

  2. Acute, fatal Sarcocystis calchasi-associated hepatitis in Roller pigeons (Columba livia f. dom.) at Philadelphia Zoo.

    Science.gov (United States)

    Trupkiewicz, J G; Calero-Bernal, R; Verma, S K; Mowery, J; Davison, S; Habecker, P; Georoff, T A; Ialeggio, D M; Dubey, J P

    2016-01-30

    Four Roller pigeons (Columba livia f. dom.) at the Philadelphia Zoo died suddenly. Necropsy examination revealed macroscopic hepatitis. Microscopically, the predominant lesions were in liver, characterized with necrosis and mixed cell inflammatory response. Sarcocystis calchasi-like schizonts and free merozoites were identified in liver. Transmission electron microscopy confirmed that schizonts were in hepatocytes. A few schizonts were in spleen. PCR using S. calchasi-specific primers confirmed the diagnosis. Neither lesions nor protozoa were found in brain and muscles. This is the first report of acute visceral S. calchasi-associated sarcocystosis in naturally infected avian hosts.

  3. Can Vacuum Assisted Venous Drainage be Achieved using a Roller Pump in an Emergency? A Pilot Study using Neonatal Circuitry

    OpenAIRE

    Hill, S L; Holt, D. W.

    2007-01-01

    There has been much advancement in perfusion technology over its 50 years of progression. One of these techniques is vacuum-assisted venous drainage (VAVD). Many perfusionists augment venous drainage using VAVD, typically from a wall vacuum source. This study explores alternates to providing VAVD if the wall vacuum fails. In two porcine laboratories, ∼36 in. of 3/16-in. tubing was connected to a sucker return port and placed into the roller head next to the arterial pump. The vacuum was monit...

  4. Computer program for analysis of high speed, single row, angular contact, spherical roller bearing, SASHBEAN. Volume 1: User's guide

    Science.gov (United States)

    Aggarwal, Arun K.

    1993-09-01

    The computer program SASHBEAN (Sikorsky Aircraft Spherical Roller High Speed Bearing Analysis) analyzes and predicts the operating characteristics of a Single Row, Angular Contact, Spherical Roller Bearing (SRACSRB). The program runs on an IBM or IBM compatible personal computer, and for a given set of input data analyzes the bearing design for it's ring deflections (axial and radial), roller deflections, contact areas and stresses, induced axial thrust, rolling element and cage rotation speeds, lubrication parameters, fatigue lives, and amount of heat generated in the bearing. The dynamic loading of rollers due to centrifugal forces and gyroscopic moments, which becomes quite significant at high speeds, is fully considered in this analysis. For a known application and it's parameters, the program is also capable of performing steady-state and time-transient thermal analyses of the bearing system. The steady-state analysis capability allows the user to estimate the expected steady-state temperature map in and around the bearing under normal operating conditions. On the other hand, the transient analysis feature provides the user a means to simulate the 'lost lubricant' condition and predict a time-temperature history of various critical points in the system. The bearing's 'time-to-failure' estimate may also be made from this (transient) analysis by considering the bearing as failed when a certain temperature limit is reached in the bearing components. The program is fully interactive and allows the user to get started and access most of its features with a minimal of training. For the most part, the program is menu driven, and adequate help messages were provided to guide a new user through various menu options and data input screens. All input data, both for mechanical and thermal analyses, are read through graphical input screens, thereby eliminating any need of a separate text editor/word processor to edit/create data files. Provision is also available to select

  5. Features of development of Stevia rebaudiana shoots cultivated in the roller bioreactor and their production of steviol glycosides.

    Science.gov (United States)

    Bondarev, Nikolai; Reshetnyak, Oxana; Nosov, Alexander

    2002-08-01

    Growth and development of Stevia rebaudiana shoots cultivated in the roller bioreactor and their production of steviol glycosides (SGs) were investigated. It was found that, owing to the highly favorable conditions of shoot cultivation created in such an apparatus, the intensity of shoot growth and SG production appeared to be 1.5 - 2.0 times higher than those of the shoots grown in tubes. These results indicate the existence of a positive correlation between these two processes. The data obtained suggest that the enhanced SG production is due to the differentiation of chlorenchyma cells and formation of specific subcellular structures for the glycoside to be accumulated.

  6. Design and Experiment of A New Corn Husking Roller%新型玉米剥皮辊的制作与试验

    Institute of Scientific and Technical Information of China (English)

    张西群; 张辉辰; 陈敬者; 张俊杰; 彭发智; 陈素英

    2015-01-01

    At present , our country corn husker widely exists in the low work efficiency , the huskling rate is low , high rates of breakage and poor processing technology , replacing the high cost of repair , seriously restricted the use and development of maize mechanical harvesting .And the key to solve the above problems lies in the performance of corn husking roller , the design and experiment of new corn husking roller .This paper introduces the new corn husking roller structure, productionmethod and the test results.The results show that: compared with the traditionalpeeling device adopts full rubber roller or cast iron roller , effectively solve the rollers ,low life difficult problem of the high rate of iron roller breakage , improving the peeling rate , a lower wear rate , and increasing the service life , reduce maintenance costs , The properties of husking roller have greatly improved .%我国的玉米剥皮装置普遍存在着作业效率低、剥净率低、破损率高、加工工艺性差及维修更换成本高等问题,严重制约了玉米机械收获的使用与发展。为此,进行了新型玉米剥皮辊的设计与试验。研究结果表明:与传统剥皮装置采用全橡胶辊或铸铁辊相比,新疆玉米剥皮辊有效地解决了胶辊寿命低、铁辊破损率高的难题,其剥净率93%、籽粒损失率0.91%、籽粒破碎率0.69%,增加使用寿命2~3倍,降低了维护成本,剥皮性能有了很大提高。

  7. Sealing features of radial feed roller spinning formed LR6 battery%LR6电池径向旋压封口的密封特性

    Institute of Scientific and Technical Information of China (English)

    楼晓天

    2013-01-01

    Sealing characteristics of LR6 battery prepared by different spinning sealing process were studied.The sealing performance of batteries prepared by axial feed opposite roller spinning sealing process was better than those of radial feed 3-roller spinning crimping and necking process.%研究了不同旋压封口工艺制备的LR6电池的密封特性.对轮轴向进给旋压制备的电池有更好的密封性能.

  8. Production of Highly Lubricious Ti-Based Ceramic Films for Reducing Friction between Web and Transiting Roller

    Science.gov (United States)

    Kohzaki, Masao; Makita, Ryohei

    2013-05-01

    Web transiting process machines have been developed for producing flexible and printed electronics. For establishing a stable roll-to-roll transportation without web defects, the friction coefficient between the web and the transiting roller should be controlled at a low value. We produced the titanium nitride-molybdenum disulfide (TiN-MoS2) composite films by DC magnetron sputtering for improving the frictional characteristics of the transiting roller used in manufacturing process of flexible and printed electronics. The hardness of the TiN-MoS2 films was about 17 GPa at 22% MoS2. The composite films containing 22% MoS2 showed a low friction coefficient of approximately 0.1 at room temperature, which was almost equal to that of diamond-like carbon (DLC) films. In addition, only a small wear was detected on the films after the friction test. The adhesive strength of the composite films was improved by forming the Ti interlayer, and the further reduction of wear was observed.

  9. Picrosirius red staining assessment of collagen after dermal roller application: A minimally invasive percutaneous collagen induction therapy

    Directory of Open Access Journals (Sweden)

    Fatma El-Zahraa Salah El-Deen Yassin

    2014-01-01

    Full Text Available Background: Percutaneous collagen induction (PCI through dermal roller breaks old collagen strands, promotes removal of damaged collagen and induces more collagen formation. Collagen fibers can be assessed by traditional stains or by polarized light assessment of Picrosirius red stain. Objective: The purpose of the current study is the clinical and histopathological evaluation of percutaneous collagen formation in atrophic acne scars after dermal roller application. Patients and Methods: Total study duration was 26 weeks in which 12 patients received seven sessions of PCI at 3-weeks interval, 3 mm punch biopsy specimens of scars were obtained before and after treatment (at 18 and 26 weeks. Microscopic examination of pre and post operative biopsies were done, using routine stains and Picrosirius red stain. Results: PCI induced notable improvement in the appearance of acne scars with significant reduction in the score from 123.3 ± 24.5 to 74.16 ± 16.49 (P = 0.00 after 26 weeks. Polarized light assessment of Picrosirius red stain clarified the gradual replacement of old thick orange-red birefringent collagen fibers by newly synthesized thin green-yellow birefringent ones postoperatively. Conclusion: Skin needling is a simple and minimally invasive procedure. The polarized light assessment of Picrosirius red stain clarified the change of the optical properties of collagen fibers according to the maturation process.

  10. Can vacuum assisted venous drainage be achieved using a roller pump in an emergency? A pilot study using neonatal circuitry.

    Science.gov (United States)

    Hill, S L; Holt, D W

    2007-12-01

    There has been much advancement in perfusion technology over its 50 years of progression. One of these techniques is vacuum-assisted venous drainage (VAVD). Many perfusionists augment venous drainage using VAVD, typically from a wall vacuum source. This study explores alternates to providing VAVD if the wall vacuum fails. In two porcine laboratories, approximately 36 in. of 3/16-in. tubing was connected to a sucker return port and placed into the roller head next to the arterial pump. The vacuum was monitored with a DLP pressure monitoring system (Medtronic). This system was connected to small-bore tubing and attached to a stopcock on top of the reservoir. The vacuum was regulated using another stopcock connected to a non-filtered luer lock port on top of the reservoir or by a segment of 3 x 0.25-in.-diameter tubing attached to the vent port with a c-clamp. Vacuum drainage was achieved, ranging from -18 mmHg to -71 mmHg by manipulating the stopcock or c-clamp. Changes in venous drainage were seen by volume fluctuations in the venous reservoir. The vacuum was adjusted to account for dramatic changes. Augmented venous drainage using a roller pump can be achieved successfully during cardiopulmonary bypass (CPB). This method of active drainage can be used in lieu of wall suction or during times of emergency if wall suction fails.

  11. Comparison of the standard roller pump and a pulsatile centrifugal pump for extracorporeal circulation during routine coronary artery bypass grafting.

    Science.gov (United States)

    Driessen, J J; Fransen, G; Rondelez, L; Schelstraete, E; Gevaert, L

    1991-01-01

    The present prospective study compared the standard nonpulsatile twin roller pump with the Sarns centrifugal pump, in the pulsatile mode, as arterial pumps for extracorporeal circulation during coronary artery bypass grafting (CABG). The study was conducted in two consecutive groups of 25 patients receiving a standard anaesthetic and surgical protocol. The investigated parameters included haemodynamic profiles, oxygen exchange, blood gas and acid-base homeostasis, haematology, coagulation and complement consumption. With comparable settings for pump flow, gas flow and delivered oxygen concentrations, there was no difference between the groups in the main haemodynamic parameters during cardiopulmonary bypass (CPB). However, a tenfold lower dose of sodium nitroprusside was required to keep systemic vascular resistance within physiologic limits during CPB in the centrifugal group (C group) compared with the roller group (R group). During rewarming oxygen extraction was higher in the C group than in the R group. During the first eight hours after CPB no differences in haemodynamics, oxygenation parameters and pulmonary shunt between the groups were observed. During, as well as after, CPB there was no significant difference in blood gas and acid-base homeostasis between either group. Average postoperative blood loss via chest tubes, total transfusions of blood products, haemoglobin and coagulation did not differ between the two groups. However, the white blood cell count, corrected for changes in haematocrit, decreased during the early phase of CPB in the R group, but not in the C group.(ABSTRACT TRUNCATED AT 250 WORDS)

  12. TEHL analysis of high-speed and heavy-load roller bearing with quasi-dynamic characteristics

    Directory of Open Access Journals (Sweden)

    Shi Xiujiang

    2015-08-01

    Full Text Available In this paper, the aero-engine mainshaft roller bearing D1842926 under typical operating conditions is taken as a case study, a new integrated numerical algorithm of quasi-dynamics and thermal elastohydrodynamic lubrication (TEHL is put forward, which can complete the bearing lubricated analysis from global dynamic performance to local TEHL state and break out of the traditional analysis way carried out independently in their own field. The 3-D film thickness distributions with different cases are given through integrated numerical algorithm, meanwhile the minimum film thickness of quasi-dynamic analysis, integrated numerical algorithm and testing are compared, which show that integrated numerical results have good agreements with the testing data, so the algorithm is demonstrated available and can judge the lubrication state more accurately. The parameter effects of operating and structure on pv value, cage sliding rate, TEHL film pressure, thickness and temperature are researched, which will provide an important theoretical basis for the structure design and optimization of aero-engine mainshaft roller bearing.

  13. Human Capital Tracking Tool -

    Data.gov (United States)

    Department of Transportation — AVS is now required to collect, track, and report on data from the following Flight, Business and Workforce Plan. The Human Resource Management’s Performance Target...

  14. Track Loading Vehicle - TLV

    Data.gov (United States)

    Federal Laboratory Consortium — The TLV is designed to apply forces close to the strength limits of the rails and other track structure components, such as ties, rail fasteners, and ballast, while...

  15. 1996 : Track Count Protocol

    Data.gov (United States)

    US Fish and Wildlife Service, Department of the Interior — The goal of St. Vincent National Wildlife Refuge's Track Count Protocol is to provide an index to the population size of game animals inhabiting St. Vincent Island.

  16. Case Analysis Tracking System

    Data.gov (United States)

    National Archives and Records Administration — CATS tracks Public and Federal Agency Reference Requests for OPF (Official Personnel Folder) , EMF (Employee Medical Folder), and eOPF (electronic Official Personnel...

  17. Financial Disclosure Tracking System

    Data.gov (United States)

    US Agency for International Development — USAID's FDTS identifies personal service contractors and local employees who should file disclosure reports. It tracks late filers and identifies those who must take...

  18. Matter Tracking Information System -

    Data.gov (United States)

    Department of Transportation — The Matter Tracking Information System (MTIS) principle function is to streamline and integrate the workload and work activity generated or addressed by our 300 plus...

  19. Neonate turtle tracking data

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — The objectives of this project are to use novel satellite tracking methods to provide improved estimation of threats at foraging areas and along migration routes for...

  20. LHCb on track

    CERN Multimedia

    2006-01-01

    On 7 and 8 June 2006, the last large component of the LHCb experiment was lowered into the cavern. This 10-tonne, 18-metre long metal structure known as 'the bridge' will support the LHCb tracking system.

  1. Patient Treatment Tracking Chart

    Science.gov (United States)

    ... Treatment Tracking Chart Viral Hepatitis Menu Menu Viral Hepatitis Viral Hepatitis Home For Veterans and the Public Veterans ... can record dates of blood work, laboratory values, hepatitis C viral load levels, medication dosages, and side effects. You ...

  2. Energy Tracking Software Platform

    Energy Technology Data Exchange (ETDEWEB)

    Ryan Davis; Nathan Bird; Rebecca Birx; Hal Knowles

    2011-04-04

    Acceleration has created an interactive energy tracking and visualization platform that supports decreasing electric, water, and gas usage. Homeowners have access to tools that allow them to gauge their use and track progress toward a smaller energy footprint. Real estate agents have access to consumption data, allowing for sharing a comparison with potential home buyers. Home builders have the opportunity to compare their neighborhood's energy efficiency with competitors. Home energy raters have a tool for gauging the progress of their clients after efficiency changes. And, social groups are able to help encourage members to reduce their energy bills and help their environment. EnergyIT.com is the business umbrella for all energy tracking solutions and is designed to provide information about our energy tracking software and promote sales. CompareAndConserve.com (Gainesville-Green.com) helps homeowners conserve energy through education and competition. ToolsForTenants.com helps renters factor energy usage into their housing decisions.

  3. Tracking Performance at LHCb

    CERN Multimedia

    Wandernoth, S

    2010-01-01

    We present the tracking performance at LHCb by showing the mass resolution, impact parameter resolution and proper time resolution of the first data taken at LHCb. Furthermore several methods to estimate the tagging efficiency on data are presented.

  4. Procurement Tracking System (PTS)

    Data.gov (United States)

    Office of Personnel Management — The Procurement Tracking System (PTS) is used solely by the procurement staff of the Office of the Inspector General (OIG) at the U.S. Office of Personnel Management...

  5. LHCb VELO Tracking Resolutions

    CERN Multimedia

    Alexander, Michael

    2011-01-01

    The excellent tracking performance of the Vertex Locator (VELO) at LHCb is presented. The resolutions it achieves on single hits, impact parameters, and primary vertex positions are shown, with particular attention paid to measurement of impact parameters.

  6. Applied eye tracking research

    NARCIS (Netherlands)

    Jarodzka, Halszka

    2011-01-01

    Jarodzka, H. (2010, 12 November). Applied eye tracking research. Presentation and Labtour for Vereniging Gewone Leden in oprichting (VGL i.o.), Heerlen, The Netherlands: Open University of the Netherlands.

  7. Jet Car Track Site

    Data.gov (United States)

    Federal Laboratory Consortium — Located in Lakehurst, New Jersey, the Jet Car Track Site supports jet cars with J57 engines and has a maximum jet car thrust of 42,000 pounds with a maximum speed of...

  8. Applied eye tracking research

    NARCIS (Netherlands)

    Jarodzka, Halszka

    2011-01-01

    Jarodzka, H. (2010, 12 November). Applied eye tracking research. Presentation and Labtour for Vereniging Gewone Leden in oprichting (VGL i.o.), Heerlen, The Netherlands: Open University of the Netherlands.

  9. Function integrated track system

    OpenAIRE

    Hohnecker, Eberhard

    2010-01-01

    The paper discusses a function integrated track system that focuses on the reduction of acoustic emissions from railway lines. It is shown that the combination of an embedded rail system (ERS), a sound absorbing track surface, and an integrated mini sound barrier has significant acoustic advantages compared to a standard ballast superstructure. The acoustic advantages of an embedded rail system are particularly pronounced in the case of railway bridges. Finally, it is shown that a...

  10. Vehicle Tracking and Security

    Science.gov (United States)

    Scorer, A. G.

    1998-09-01

    This paper covers the wide area and short range locational technologies that are available for vehicle tracking in particular and mobile user security in general. It also summarises the radio communications services that can deliver information to the user. It considers the use that can be made of these technologies, when combined with procedures for delivering a response, in the security field, notably in relation to personal security, high-value load protection and the after-theft tracking markets.

  11. Provenance Tracking in UNICORE

    OpenAIRE

    Giesler, André; Hagemeier, Björn; Czekala, Myriam

    2015-01-01

    The automated tracking and storage of provenance information allows users of scientific workflow systems to validate and reproduce results of their experiments. Until now, UNICORE has not been providing comprehensive provenance features. For this reason, we plan to equip UNICORE with a flexible provenance tracking mechanism. Our goal is to ensure a suitable traceability of job and workflow processes into a description format supporting query capabilities and interoperability. In a first step,...

  12. MATERIAL TRACKING USING LANMAS

    Energy Technology Data Exchange (ETDEWEB)

    Armstrong, F.

    2010-06-07

    LANMAS is a transaction-based nuclear material accountability software product developed to replace outdated and legacy accountability systems throughout the DOE. The core underlying purpose of LANMAS is to track nuclear materials inventory and report transactions (movement, mixing, splitting, decay, etc.) to the Nuclear Materials Management and Safeguards System (NMMSS). While LANMAS performs those functions well, there are many additional functions provided by the software product. As a material is received onto a site or created at a site, its entire lifecycle can be tracked in LANMAS complete to its termination of safeguards. There are separate functions to track material movements between and within material balance areas (MBAs). The level of detail for movements within a MBA is configurable by each site and can be as high as a site designation or as detailed as building/room/rack/row/position. Functionality exists to track the processing of materials, either as individual items or by modeling a bulk process as an individual item to track inputs and outputs from the process. In cases where sites have specialized needs, the system is designed to be flexible so that site specific functionality can be integrated into the product. This paper will demonstrate how the software can be used to input material into an account and track it to its termination of safeguards.

  13. 75 FR 76297 - Defense Federal Acquisition Regulation Supplement; Restriction on Ball and Roller Bearings (DFARS...

    Science.gov (United States)

    2010-12-08

    ... devote the time to market research and tracking the supply chain to demonstrate the availability of... waive the restriction on a case-by-case basis by certifying that adequate domestic supplies are not... must be treated as nondomestic because the manufacturer is unable to certify to domestic sourcing of...

  14. Computer program for analysis of high speed, single row, angular contact, spherical roller bearing, SASHBEAN. Volume 2: Mathematical formulation and analysis

    Science.gov (United States)

    Aggarwal, Arun K.

    1993-01-01

    Spherical roller bearings have typically been used in applications with speeds limited to about 5000 rpm and loads limited for operation at less than about 0.25 million DN. However, spherical roller bearings are now being designed for high load and high speed applications including aerospace applications. A computer program, SASHBEAN, was developed to provide an analytical tool to design, analyze, and predict the performance of high speed, single row, angular contact (including zero contact angle), spherical roller bearings. The material presented is the mathematical formulation and analytical methods used to develop computer program SASHBEAN. For a given set of operating conditions, the program calculates the bearings ring deflections (axial and radial), roller deflections, contact areas stresses, depth and magnitude of maximum shear stresses, axial thrust, rolling element and cage rotational speeds, lubrication parameters, fatigue lives, and rates of heat generation. Centrifugal forces and gyroscopic moments are fully considered. The program is also capable of performing steady-state and time-transient thermal analyses of the bearing system.

  15. Running on Empty: Schools Cope with the Roller-Coaster World of Cost Run-Ups and Budget Let-Downs

    Science.gov (United States)

    LaFee, Scott

    2009-01-01

    Public education is like riding a roller-coaster, except that in education the thrill tends to come on the way up, when the economy is flying high, and funding is flush and the future feels as bracing as the wind rushing past. However, this is not one of those times. The economy seems to be almost in free fall. Optimism plummets with each…

  16. Innovative design to prevent reversal of roller blood pump rotation in the event of electromechanical failure: an easy solution to a devastating problem.

    Science.gov (United States)

    Skoletsky, Jennifer S; White, Brian T; Austin, Jon W

    2007-06-01

    Despite the advanced technologies of battery back-up for heart-lung consoles and the availability of system-wide generators, electromechanical failure is still occurring. Several heart-lung machine manufacturers still provide unsafe handcranking devices to use in the case of an emergency while using a roller blood pump. A new design has been engineered to eliminate safety and quality issues for the perfusionist and the patient when the need for handcranking presents itself. A ratchet-style handcranking device was fabricated by means of a steel plate with adjustable pins. The adjustable pins allow for use with different models of the Cobe, Stockert, and Jostra heart-lung consoles, which contain roller pumps with 1800 roller heads. Additional modifications such as a 1:2 transmission and fluorescent markers are also used in the design. This innovative design is an improvement in safety compared with the current handcrank provided by Cobe, Stockert, and Jostra. With this modified handcranking device, accidental reverse rotation of the roller pump head cannot occur. Fluorescent markers will improve visualization of the pump head in low-light situations. The ergonomic design improves efficiency by reducing fatigue. Most importantly, a "safe" safety device will replace the current design provided by these manufacturers, thus improving the quality of care by health care providers.

  17. Application of ANSYS in Casting for Centrifugal Compound Roller%ANSYS在离心复合轧辊铸造过程中的应用

    Institute of Scientific and Technical Information of China (English)

    边明茹; 张龙

    2013-01-01

    By applying simulation software ANSYS and combining with practical data of roller production ,the temperature field at the casting and solidification of centrifugal compound roller is simulated, the simulation result provides scientific study ways for formulating rational casting technology of the centrifugal casting,and can improve the product stability of centrifugal casting rollers,which provides design bases and study ways for developing high-powered centrifugal roller.%  应用仿真软件ANSYS,结合轧辊实际生产实践数据,对离心复合轧辊铸造凝固过程的温度场进行仿真模拟,研究仿真结果为轧辊离心铸造制定合理的铸造工艺,提供科学的研究方法,并提高离心铸造轧辊的产品稳定性,对开发高性能的离心轧辊提供有效的设计依据和研究途径。

  18. Running on Empty: Schools Cope with the Roller-Coaster World of Cost Run-Ups and Budget Let-Downs

    Science.gov (United States)

    LaFee, Scott

    2009-01-01

    Public education is like riding a roller-coaster, except that in education the thrill tends to come on the way up, when the economy is flying high, and funding is flush and the future feels as bracing as the wind rushing past. However, this is not one of those times. The economy seems to be almost in free fall. Optimism plummets with each…

  19. Theoretical Research of Radiant Intensity of Roller Hearth Furnace%辊底式热处理炉辐射强度的理论研究

    Institute of Scientific and Technical Information of China (English)

    吴永红

    2012-01-01

    The heat transfer mathematical model between the furnace wall, the radiant tube and the plate (roller) of the roller hearth furnace for steel heat treatment was established to solve the design problem. The influences of radiant intensity of radiant tube on the furnace temperature rate and the radiant tube surface temperature were studied. The value range of the radiant tube radiant intensity of roller hearth furnace was calculated and determined in theory, and the important significance of the radiant intensity for the design of the roller hearth furnace was revealed. Furthermore, through integrating theory with practice, the study results were further confirmed.%针对钢板热处理用辊底式热处理炉的设计,建立了炉墙、辐射管以及炉辊(钢板)之间的传热数学模型,研究了辐射管的辐射强度对炉子升温速度以及辐射管表面温度的影响.从理论上计算并确定了辊底式热处理炉辐射管辐射强度的取值范围,揭示了辐射强度对辊底式热处理炉设计的重要意义,并且通过理论与实际相结合,对研究结果进行了进一步的验证.

  20. Kinetic Analysis of Anti-spin Thread Connection Elastic Roller Based on ABAQUS%基于ABAQUS反旋对接弹性滚子的动力学分析

    Institute of Scientific and Technical Information of China (English)

    卢黎明; 秦豫江; 蔡颖

    2014-01-01

    This paper presents a new anti-spin thread connection elastic roller(ASTCER)that substitutes unidi-rectional helical elastic roller through structural design innovation with spring structure parameters. The finite element analysis model of ordinary cylindrical rollers,unidirectional spiral elastic rollers and anti-spin thread connection elastic rollers is established based on the ABAQUS. The axial displacement of their center of mass and the stress distribution of anti-spin thread connection elastic rollers are analyzed through their stress compari-son. Theoretical studies show that the new anti-spin thread connection elastic roller inherits some advantages of the unidirectional spiral elastic rollers and can avoid the axial offset of the single spiral elastic roller in motion and the huge wear in contact with the inner and outer rings.%借助弹簧结构参数以及结构设计创新,提出了一种替代单向螺旋弹性滚子的新型反旋对接弹性滚子。通过ABAQUS建立了普通圆柱滚子、单向螺旋弹性滚子及反旋对接弹性滚子的有限元分析模型,对比分析了它们的质心轴向位移及反旋对接弹性滚子对接面的应力分布情况。研究表明这种新型反旋对接弹性滚子能继承单向螺旋弹性滚子的主要优点,且能避免单旋向螺旋弹性滚子在运动中的轴向偏移及因此与内外圈挡边接触产生较大的磨损。