Roller Testing to Mimic Damage of the ISS SARJ Ring and Durability Test to Simulate Fifteen Years of SARJ Operation Using the Damaged Surface

NASA Technical Reports Server (NTRS)

Krantz, Timothy L.; Elchert, Justin P.; DellaCorte, Christopher; Dube, Michael J.

2016-01-01

The International Space Station's starboard Solar Alpha Rotary Joint (SARJ) experienced a breakdown of the joint's race ring surface. The starboard SARJ mechanism was cleaned and lubricated with grease. To provide some guidance on the expected behavior of the damaged SARJ ring with continued operations, experiments were conducted using rollers and a vacuum roller test rig. The approach of the experimental work involved three main steps: (1) initiate damage using conditions representative of the SARJ with inadequate lubrication; (2) propagate the damage by operating the test rollers without lubrication; and (3) assess the durability of the roller by testing to simulate the equivalent of 15 years of SARJ operation on the damaged surface assuming adequate grease lubrication. During the rig testing, additional and/or replacement grease was introduced at regular intervals to maintain good lubrication in the rig. The damage to the nitride layer continued even after application of grease. The grease lubrication proved to be effective for limiting the value of the axial force that can be developed. Limiting the axial force on the SARJ mechanism is important since the larger the axial force the more concentrated the load pressure becomes on the blend-radius location on the SARJ roller. After the testing simulating 15 years of SARJ operations, the wear depths were the order of 0.2 mm for the nitrided 15-5 roller and the order of 0.06 mm for the mating 440C roller. Metallographic inspections were done to search for indications of impending fatigue or other fracture indications that might eventually propagate and cause structural failure. There were no indications or features found that could eventually compromise structural integrity.

The Shock and Vibration Bulletin. Part 1. Invited Papers, Submarine Shock Testing, Shock Analysis, Shock Testing

DTIC Science & Technology

1973-06-01

approximately 4. Use of a cold gas for determining was determined and presented in Figure 3. This analysis was unsteady flow characteristics and...driven by a hydraulic motor. shown experimentally that drawbar force re- Roller motion develops a high rotating force , ductions greater than one part in...of doors, a water table flow bient pressure. The interest in determining this decay time is analogy was used. With this analogy, a two-dimensional

Failure Analysis of a CH-47 Horizontal Hinge Pin Assembly, P/N 114RS226

DTIC Science & Technology

2006-12-01

and globular) dispersed in a matrix of tempered martensite observed in all the metallographic cross sections produced from the M50 steel rings and...ring, were shown to have met the requirements of AMS 6491 (1)—the specification for VIM- VAR M50 required by each roller- bearing set drawing (see table...2). Although the phosphorus content for each part was at or near the maximum level allowed by AMS 6491, literature on M50 steel and a conversation

Optical Fiber On-Line Detection System for Non-Touch Monitoring Roller Shape

NASA Astrophysics Data System (ADS)

Guo, Y.; Wang, Y. T.

2006-10-01

Basing on the principle of reflective displacement fiber-optic sensor, a high accuracy non-touch on-line optical fiber measurement system for roller shape is presented. The principle and composition of the detection system and the operation process are expatiated also. By using a novel probe of three optical fibers in equal transverse space, the effects of fluctuations in the light source, reflective changing of target surface and the intensity losses in the fiber lines are automatically compensated. Meantime, an optical fiber sensor model of correcting static error based on BP artificial neural network (ANN) is set up. Also by using interpolation method and value filtering to process the signals, effectively reduce the influence of random noise and the vibration of the roller bearing. So enhance the accuracy and resolution remarkably. Experiment proves that the accuracy of the system reach to the demand of practical production process, it provides a new method for the high speed, accurate and automatic on line detection of the mill roller shape.

A single center's conversion from roller pump to centrifugal pump technology in extracorporeal membrane oxygenation.

PubMed

Shade, Brandon C; Schiavo, Kellie; Rosenthal, Tami; Connelly, James T; Melchior, Richard W

2016-06-05

Recent advances in blood pump technology have led to an increased use of centrifugal pumps for prolonged extracorporeal membrane oxygenation (ECMO). Data from the Extracorporeal Life Support Organization confirms that many institutions have converted to centrifugal pumps after prior experience with roller pump technology. Centrifugal pump technology is more compact and may generate less heat and hemolysis than a conventional roller pump. Based on the potential advantages of centrifugal pumps, a decision was made institution-wide to convert to centrifugal pump technology in pediatric implementation of ECMO. Based on limited prior experience with centrifugal pumps, a multidisciplinary approach was used to implement this new technology. The new centrifugal pump (Sorin Revolution, Arvada, CO) was intended for ECMO support in the cardiac intensive care unit (CICU), the pediatric intensive care unit (PICU) and the neonatal intensive care unit (NICU). The perfusion team used their knowledge and expertise with centrifugal pumps to create the necessary teaching tools and interactive training sessions for the technical specialists who consisted primarily of registered nurses and respiratory therapists. The first phase consisted of educating all personnel involved in the care of the ECMO patient, followed by patient implementation in the CICU, followed by the PICU and NICU. The institution-wide conversion took several months to complete and was well received among all disciplines in the CICU and PICU. The NICU personnel did use the centrifugal pump circuit, but decided to revert back to using the roller pump technology. A systematic transition from roller pump to centrifugal pump technology with a multidisciplinary team can ensure a safe and successful implementation. © The Author(s) 2016.

Neural correlate of spatial presence in an arousing and noninteractive virtual reality: an EEG and psychophysiology study.

PubMed

Baumgartner, Thomas; Valko, Lilian; Esslen, Michaela; Jäncke, Lutz

2006-02-01

Using electroencephalography (EEG), psychophysiology, and psychometric measures, this is the first study which investigated the neurophysiological underpinnings of spatial presence. Spatial presence is considered a sense of being physically situated within a spatial environment portrayed by a medium (e.g., television, virtual reality). Twelve healthy children and 11 healthy adolescents were watching different virtual roller coaster scenarios. During a control session, the roller coaster cab drove through a horizontal roundabout track. The following realistic roller coaster rides consisted of spectacular ups, downs, and loops. Low-resolution brain electromagnetic tomography (LORETA) and event-related desynchronization (ERD) were used to analyze the EEG data. As expected, we found that, compared to the control condition, experiencing a virtual roller coaster ride evoked in both groups strong SP experiences, increased electrodermal reactions, and activations in parietal brain areas known to be involved in spatial navigation. In addition, brain areas that receive homeostatic afferents from somatic and visceral sensations of the body were strongly activated. Most interesting, children (as compared to adolescents) reported higher spatial presence experiences and demonstrated a different frontal activation pattern. While adolescents showed increased activation in prefrontal areas known to be involved in the control of executive functions, children demonstrated a decreased activity in these brain regions. Interestingly, recent neuroanatomical and neurophysiological studies have shown that the frontal brain continues to develop to adult status well into adolescence. Thus, the result of our study implies that the increased spatial presence experience in children may result from the not fully developed control functions of the frontal cortex.

Effect of Roller Geometry on Roller Bearing Load-Life Relation

NASA Technical Reports Server (NTRS)

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.

Cross transfer acute effects of foam rolling with vibration on ankle dorsiflexion range of motion.

PubMed

García-Gutiérrez, María Teresa; Guillén-Rogel, Paloma; Cochrane, Darryl J; Marín, Pedro J

2018-06-01

Foam roller is a device used as a massage intervention for rehabilitation and fitness performance. To examine the effects on the ankle dorsiflexion mobility of the foam roller as well as the combination of foam roller and vibration applied to the ankle plantarflexors muscles, and to observe the possible cross-effect. Thirty-eight undergraduate students participated in the study (19 males and 19 females). This study investigated. Three conditions (3 sets of 20 s) were performed in a randomized order (independent variables): 1) foam roller (Roller), 2) foam roller and vibration (Roller+VIB), and 3) no foam roller or vibration (Control). to determine whether of foam roller with or without vibration would benefit ankle dorsiflexion mobility. Ankle dorsiflexion ROM and plantar flexor were measured in both legs before and immediately after the treatment. A cross-effect was found in the non-stimulated leg. There was a significant effect on ankle mobility of Roller and Roller+VIB conditions (6% and 7%, p<0.001). Foam roller massage and vibration stimulus' foam roller massage increase ankle mobility producing a cross-effect.

The numerical simulation and experiment on extrusion roller embossing of light diffusion plate with micro-structure

NASA Astrophysics Data System (ADS)

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

2018-01-01

Extrusion roller embossing process has demonstrated the ability to produce polymer film with micro-structure. However the influence of various parameters on the forming quality has not been understood clearly. In this paper, a light diffusion plate with semi cylindrical micro-structure array as the research object, the influence of the main processing parameters such as roller speed, pressuring distance and polymer film temperature to the rolling quality was investigated in detail by simulation and experimental methods. The results show that the thickness of the light diffusion plate and the micro-structure fitting diameter increases with the increasing of the roll speed and the polymer film temperature, and decreases with the increasing of the pressing distance. Besides, the simulation results conformed well to the experimental results.

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

PubMed

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. Are foam rollers or roller massagers effective for increasing hamstrings flexibility in asymptomatic physically active adults? Summary of Key Findings: The literature was searched for studies on the effects of using foam rollers or roller massagers to increase hamstrings flexibility in asymptomatic physically active adults. Four randomized controlled trials were included; 2 studies provided level 2 or 3 evidence regarding foam rollers and 2 studies provided level 2 or 3 evidence regarding roller massagers. Both roller-massager studies reported increases in hamstrings flexibility after treatment. Data from the foam-roller studies did not demonstrate a statistically significant increase in hamstrings flexibility, but 1 study did demonstrate a strong effect size. Clinical Bottom Line: The reviewed moderate-quality studies support the use of roller massagers but provide limited evidence on the effectiveness of foam rolling to increase hamstrings flexibility in asymptomatic physically active adults. Flexibility gains may be improved by a longer duration of treatment and administration by a trained therapist. Gains appear to decline rapidly postrolling. Neither device has been shown to confer a therapeutic benefit superior to static stretching, and the effectiveness of these devices for preventing injury is unknown. Strength of Recommendation: Grade B evidence supports the use of roller massagers to increase hamstrings flexibility in asymptomatic physically active adults.

Roller bearing geometry design

NASA Technical Reports Server (NTRS)

Savage, M.; Pinkston, B. H. W.

1976-01-01

A theory of kinematic stabilization of rolling cylinders is extended and applied to the design of cylindrical roller bearings. The kinematic stabilization mechanism puts a reverse skew into the rolling elements by changing the roller taper. Twelve basic bearing modification designs are identified amd modeled. Four have single transverse convex curvature in their rollers while eight have rollers which have compound transverse curvature made up of a central cylindrical band surrounded by symmetric bands with slope and transverse curvature. The bearing designs are modeled for restoring torque per unit axial displacement, contact stress capacity, and contact area including dynamic loading, misalignment sensitivity and roller proportion. Design programs are available which size the single transverse curvature roller designs for a series of roller slopes and load separations and which design the compound roller bearings for a series of slopes and transverse radii of curvature. The compound rollers are proportioned to have equal contact stresses and minimum size. Design examples are also given.

A 3D unstructured grid nearshore hydrodynamic model based on the vortex force formalism

NASA Astrophysics Data System (ADS)

Zheng, Peng; Li, Ming; van der A, Dominic A.; van der Zanden, Joep; Wolf, Judith; Chen, Xueen; Wang, Caixia

2017-08-01

A new three-dimensional nearshore hydrodynamic model system is developed based on the unstructured-grid version of the third generation spectral wave model SWAN (Un-SWAN) coupled with the three-dimensional ocean circulation model FVCOM to enable the full representation of the wave-current interaction in the nearshore region. A new wave-current coupling scheme is developed by adopting the vortex-force (VF) scheme to represent the wave-current interaction. The GLS turbulence model is also modified to better reproduce wave-breaking enhanced turbulence, together with a roller transport model to account for the effect of surface wave roller. This new model system is validated first against a theoretical case of obliquely incident waves on a planar beach, and then applied to three test cases: a laboratory scale experiment of normal waves on a beach with a fixed breaker bar, a field experiment of oblique incident waves on a natural, sandy barred beach (Duck'94 experiment), and a laboratory study of normal-incident waves propagating around a shore-parallel breakwater. Overall, the model predictions agree well with the available measurements in these tests, illustrating the robustness and efficiency of the present model for very different spatial scales and hydrodynamic conditions. Sensitivity tests indicate the importance of roller effects and wave energy dissipation on the mean flow (undertow) profile over the depth. These tests further suggest to adopt a spatially varying value for roller effects across the beach. In addition, the parameter values in the GLS turbulence model should be spatially inhomogeneous, which leads to better prediction of the turbulent kinetic energy and an improved prediction of the undertow velocity profile.

Effects of roller massager on muscle recovery after exercise-induced muscle damage.

PubMed

Casanova, Nuno; Reis, Joana F; Vaz, João R; Machado, Rita; Mendes, Bruno; Button, Duane C; Pezarat-Correia, Pedro; Freitas, Sandro R

2018-01-01

Two experiments (n = 10) were conducted to determine the effects of roller massager (RM) on ankle plantar flexor muscle recovery after exercise-induced muscle damage (EIMD). Experiment 1 examined both functional [i.e., ankle plantar flexion maximal isometric contraction and submaximal (30%) sustained force; ankle dorsiflexion maximal range of motion and resistance to stretch; and medial gastrocnemius pain pressure threshold] and morphological [cross-sectional area, thickness, fascicle length, and fascicle angle] variables, before and immediately, 1, 24, 48, and 72 h after an EIMD stimulus. Experiment 2 examined medial gastrocnemius deoxyhaemoglobin concentration kinetics before and 48 h after EIMD. Participants performed both experiments twice: with (RM) and without (no-roller massager; NRM) the application of a RM (6 × 45 s; 20-s rest between sets). RM intervention did not alter the functional impairment after EIMD, as well as the medial gastrocnemius morphology and oxygenation kinetics (P > 0.05). Although, an acute increase of ipsilateral (RM = + 19%, NRM = -5%, P = 0.032) and a strong tendency for contralateral (P = 0.095) medial gastrocnemius pain pressure threshold were observed. The present results suggest that a RM has no effect on plantar flexors performance, morphology, and oxygenation recovery after EIMD, except for muscle pain pressure threshold (i.e., a soreness).

Quality by design I: Application of failure mode effect analysis (FMEA) and Plackett-Burman design of experiments in the identification of "main factors" in the formulation and process design space for roller-compacted ciprofloxacin hydrochloride immediate-release tablets.

PubMed

Fahmy, Raafat; Kona, Ravikanth; Dandu, Ramesh; Xie, Walter; Claycamp, Gregg; Hoag, Stephen W

2012-12-01

As outlined in the ICH Q8(R2) guidance, identifying the critical quality attributes (CQA) is a crucial part of dosage form development; however, the number of possible formulation and processing factors that could influence the manufacturing of a pharmaceutical dosage form is enormous obviating formal study of all possible parameters and their interactions. Thus, the objective of this study is to examine how quality risk management can be used to prioritize the number of experiments needed to identify the CQA, while still maintaining an acceptable product risk profile. To conduct the study, immediate-release ciprofloxacin tablets manufactured via roller compaction were used as a prototype system. Granules were manufactured using an Alexanderwerk WP120 roller compactor and tablets were compressed on a Stokes B2 tablet press. In the early stages of development, prior knowledge was systematically incorporated into the risk assessment using failure mode and effect analysis (FMEA). The factors identified using FMEA were then followed by a quantitative assessed using a Plackett-Burman screening design. Results show that by using prior experience, literature data, and preformulation data the number of experiments could be reduced to an acceptable level, and the use of FMEA and screening designs such as the Plackett Burman can rationally guide the process of reducing the number experiments to a manageable level.

21 CFR 870.4370 - Roller-type cardiopulmonary bypass blood pump.

Code of Federal Regulations, 2010 CFR

2010-04-01

... 21 Food and Drugs 8 2010-04-01 2010-04-01 false Roller-type cardiopulmonary bypass blood pump. 870... Roller-type cardiopulmonary bypass blood pump. (a) Identification. A roller-type cardiopulmonary bypass blood pump is a device that uses a revolving roller mechanism to pump the blood through the...

21 CFR 870.4370 - Roller-type cardiopulmonary bypass blood pump.

Code of Federal Regulations, 2014 CFR

2014-04-01

... 21 Food and Drugs 8 2014-04-01 2014-04-01 false Roller-type cardiopulmonary bypass blood pump. 870... Roller-type cardiopulmonary bypass blood pump. (a) Identification. A roller-type cardiopulmonary bypass blood pump is a device that uses a revolving roller mechanism to pump the blood through the...

21 CFR 870.4370 - Roller-type cardiopulmonary bypass blood pump.

Code of Federal Regulations, 2011 CFR

2011-04-01

... 21 Food and Drugs 8 2011-04-01 2011-04-01 false Roller-type cardiopulmonary bypass blood pump. 870... Roller-type cardiopulmonary bypass blood pump. (a) Identification. A roller-type cardiopulmonary bypass blood pump is a device that uses a revolving roller mechanism to pump the blood through the...

21 CFR 870.4370 - Roller-type cardiopulmonary bypass blood pump.

Code of Federal Regulations, 2012 CFR

2012-04-01

... 21 Food and Drugs 8 2012-04-01 2012-04-01 false Roller-type cardiopulmonary bypass blood pump. 870... Roller-type cardiopulmonary bypass blood pump. (a) Identification. A roller-type cardiopulmonary bypass blood pump is a device that uses a revolving roller mechanism to pump the blood through the...

21 CFR 870.4370 - Roller-type cardiopulmonary bypass blood pump.

Code of Federal Regulations, 2013 CFR

2013-04-01

... 21 Food and Drugs 8 2013-04-01 2013-04-01 false Roller-type cardiopulmonary bypass blood pump. 870... Roller-type cardiopulmonary bypass blood pump. (a) Identification. A roller-type cardiopulmonary bypass blood pump is a device that uses a revolving roller mechanism to pump the blood through the...

Thrust rollers

NASA Technical Reports Server (NTRS)

Vranish, John M. (Inventor)

2007-01-01

A thrust roller bearing system comprising an inner rotating member, an outer rotating member and multiple rollers coupling the inner rotating member with outer rotating member. The inner and outer rotating members include thrust lips to enable the rollers to act as thrust rollers. The rollers contact inner and outer rotating members at bearing contact points along a contact line. Consequently, the radial/tilt and thrust forces move synchronously and simultaneously to create a bearing action with no slipping.

Roller unlocking sprags

NASA Technical Reports Server (NTRS)

Vranish, John M. (Inventor)

1999-01-01

A roller type sprag member consisting of three main elements, an outer roller half section, an inner roller half section, and an assembly-location pin. The sprag locks using roller locking techniques in a manner well known in the case of a three-dimensional (3-D) locking sprag. It unlocks, however, using a roll technique in which the inner and outer roller halves rotate in mutually opposite directions, one clockwise and the other counterclockwise. In the process of rotation, the roller is foreshortened between the distance across the sprag contact surfaces, whereupon it loses its ability to act as a locking sprag and releases.

Research of paste transition to substrate in LTCC-technology

NASA Astrophysics Data System (ADS)

Litunov, S. N.; Yurkov, V. Y.

2018-01-01

The electronics development demands for accuracy of printed technologies, in particular, to screen printing. Under a flat blade operation the print form is deformed and the image is distorted relative to the original. A squeegee in a form of a smooth cylinder reduces distortion, but it allows obtaining satisfactory print quality only when using high density grids. The paper shows findings of using roller squeegee with dosed ink supply. The roller squeegee is provided with an elastic layer. Dosage is carried out due to the cells on the elastic layer surface. There were used meshes 100-31 and 120-34 for the stencil. The experiments were carried out with layers of photopolymers and rubber. The carried out calculations made possible to choose the optimum printing pressure. Under the selected conditions, the printed image had minimal distortion. The findings allow drawing a conclusion about the possibility of roller squeegee using in chips manufacture according to LTCC-technology.

Spherical roller bearing analysis. SKF computer program SPHERBEAN. Volume 1: Analysis

NASA Technical Reports Server (NTRS)

Kleckner, R. J.; Pirvics, J.

1980-01-01

The models and associated mathematics used within the SPHERBEAN computer program for prediction of the thermomechanical performance characteristics of high speed lubricated double row spherical roller bearings are presented. The analysis allows six degrees of freedom for each roller and three for each half of an optionally split cage. Roller skew, free lubricant, inertial loads, appropriate elastic and friction forces, and flexible outer ring are considered. Roller quasidynamic equilibrium is calculated for a bearing with up to 30 rollers per row, and distinct roller and flange geometries are specifiable. The user is referred to the material contained here for formulation assumptions and algorithm detail.

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

NASA Technical Reports Server (NTRS)

Anderson, William J.; Shipitalo, William

1991-01-01

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.

Traction Drives for Zero Stick-Slip Robots, and Reaction Free, Momentum Balanced Systems

NASA Technical Reports Server (NTRS)

Anderson, William J.; Shipitalo, William; Newman, Wyatt

1995-01-01

Two differential (dual input, single output) drives (a roller-gear and a pure roller), and a momentum balanced (single input, dual output) drive (pure roller ) were designed, fabricated, and tested. The differential drives are each rated at 295 rad/sec (2800 rpm) input speed, 450 N-m (4,000 in-lbf) output torque. The momentum balanced drive is rated at 302 rad/sec (2880 rpm) input speed, and dual output torques of 434N-m (3840 in-lbf). The Dual Input Differential Roller-Gear Drive (DC-700) has a planetary roller-gear system with a reduction ratio (one input driving the output with the second input fixed) of 29.23: 1. The Dual Input Differential Roller Drive (DC-500) has a planetary roller system with a reduction ratio of approximately 24:1. Each of the differential drives features dual roller-gear or roller arrangements consisting of a sun, four first row planets, four second row planets, and a ring. The Momentum Balanced (Grounded Ring) Drive (DC-400) has a planetary roller system with a reduction ratio of 24:1 with both outputs counterrotating at equal speed. Its single roller cluster consists of a sun, five first and five second row planets, a roller cage or spider and a ring. Outputs are taken from both the roller cage and the ring which counterrotate. Test results reported for all three drives include angular and torque ripple (linearity and cogging), viscous and Coulomb friction, and forward and reverse power efficiency. Of the two differential drives, the Differential Roller Drive had better linearity and less cogging than did the Differential Roller-Gear Drive, but it had higher friction and lower efficiency (particularly at low power throughput levels). Use of full preloading rather than a variable preload system in the Differential Roller Drive assessed a heavy penalty in part load efficiency. Maximum measured efficiency (ratio of power out to power in) was 95% for the Differential Roller-Gear Drive and 86% for the Differential Roller Drive. The Momentum Balanced (Grounded Ring) Drive performed as expected kinematically. Reduction r-atios to the two counterrotating outputs (design nominal=24:1) were measured to be 23.98:1 and 24.12:1 at zero load.. At 25ONm (2200 in-lbf) output torque the ratio changed 2% due to roller creep. This drive was the smoothest of all three as determined from linearity and cogging tests, and maximum measured efficiency (ratio of power out to power in) was 95%. The disadvantages of full preloading as comvared to variable preload were apparent in this drive as in the Differential Roller Drive. Efficiencies at part load were low, but improved dramatically with increases in torque. These were consistent with friction measurements which indicated losses primarily from Coulomb friction. The initial preload level setting was low so roller slip was encountered at higher torques during testing.

System for automatically aligning a support roller system under a rotating body

DOEpatents

Singletary, B. Huston

1983-01-01

Two support rings on a rotatable drum respectively engage conically tapered nd surfaces of support rollers mounted on pivot universally relative to its axis of rotation and translate therealong. Rotation of the drum on differential conical support roller diameters causes pivotal steering and axial translation of support roller until roller is centered on support rings.

Roller Coasters!

ERIC Educational Resources Information Center

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…

System for automatically aligning a support roller system under a rotating body

DOEpatents

Singletary, B.H.

1982-07-21

Two support rings on a rotatable drum respectively engage conically tapered end surfaces of support rollers mounted on pivot universally relative to its axis of rotation and translate therealong. Rotation of the drum on differential conical support roller diameters causes pivotal steering and axial translation of support roller until roller is centered on support rings.

Eco-friendly rubberized cotton fabric roller for ginning machines.

PubMed

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.

Salmonella transfer during pilot plant scale washing and roller conveying of tomatoes.

PubMed

Wang, Haiqiang; Ryser, Elliot T

2014-03-01

Salmonella transfer during washing and roller conveying of inoculated tomatoes was quantified using a pilot scale tomato packing line equipped with plastic, foam, or brush rollers. Red round tomatoes (2.3 kg) were dip inoculated with Salmonella enterica serovar Typhimurium LT2 (avirulent) (4 log CFU/g), air dried for 2 h, and then washed in sanitizer-free water for 2 min. Inoculated tomatoes were then passed single file over a 1.5-m conveyor equipped with plastic, foam, or brush rollers followed by 25 previously washed uninoculated tomatoes. Tomato samples were collected after 2 min of both washing and roller conveying, with all 25 uninoculated tomatoes collected individually after conveying. Roller surface samples were collected before and after conveying the uninoculated tomatoes. Both tomato and surface samples were quantitatively examined for Salmonella by direct plating or membrane filtration using xylose lysine Tergitol 4 agar. Regardless of the roller type, Salmonella populations on inoculated tomatoes did not significantly (P < 0.05) decrease during contact with the roller conveyors. After conveying uninoculated tomatoes over contaminated foam rollers, 96% of the 25 tomatoes were cross-contaminated with Salmonella at >100 CFU per tomato. With plastic rollers, 24 and 76% of tomatoes were cross-contaminated with Salmonella at 10 to 100 and 1 to 10 CFU per tomato, respectively. In contrast, only 8% of 25 tomatoes were cross-contaminated with brush rollers with Salmonella populations of 1 to 10 CFU per tomato. Overall, cross-contamination was greatest with foam, followed by plastic and brush rollers (P < 0.05). Adding peroxyacetic acid or chlorine to the wash water significantly decreased cross-contamination during tomato conveying, with chlorine less effective in controlling Salmonella on foam compared with plastic and brush rollers.

Kinematic correction for roller skewing

NASA Technical Reports Server (NTRS)

Savage, M.; Loewenthal, S. H.

1980-01-01

A theory of kinematic stabilization of rolling cylinders is developed for high-speed cylindrical roller bearings. This stabilization requires race and roller crowning to produce changes in the rolling geometry as the roller shifts axially. These changes put a reverse skew in the rolling elements by changing the rolling taper. Twelve basic possible bearing modifications are identified in this paper. Four have single transverse convex curvature in the rollers while eight have rollers with compound transverse curvature composed of a central cylindrical band of constant radius surrounded by symmetric bands with both slope and transverse curvature.

Kinematic correction for roller skewing

NASA Technical Reports Server (NTRS)

Savage, M.; Loewenthal, S. H.

1980-01-01

A theory of kinematic stabilization of rolling cylinders is developed for high-speed cylindrical roller bearings. This stabilization requires race and roller crowning to product changes in the rolling geometry as the roller shifts axially. These changes put a reverse skew in the rolling elements by changing the rolling taper. Twelve basic possible bearing modifications are identified in this paper. Four have single transverse convex curvature in the rollers while eight have rollers with compound transverse curvature composed of a central cylindrical band of constant radius surrounded by symmetric bands with both slope and transverse curvature.

Problematics of Reliability of Road Rollers

NASA Astrophysics Data System (ADS)

Stawowiak, Michał; Kuczaj, Mariusz

2018-06-01

This article refers to the reliability of road rollers used in a selected roadworks company. Information on the method of road rollers service and how the service affects the reliability of these rollers is presented. Attention was paid to the process of the implemented maintenance plan with regard to the machine's operational time. The reliability of road rollers was analyzed by determining and interpreting readiness coefficients.

49 CFR 230.103 - Tender roller bearing journal boxes.

Code of Federal Regulations, 2011 CFR

2011-10-01

... 49 Transportation 4 2011-10-01 2011-10-01 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. ...

49 CFR 230.103 - Tender roller bearing journal boxes.

Code of Federal Regulations, 2010 CFR

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. ...

Experimental use of rubber-tire rollers as a means of improving density in asphalt overlays.

DOT National Transportation Integrated Search

1991-01-01

This study reports the results of comparative tests on sections of asphalt pavement rolled with conventional steel-wheel rollers and those rolled with a rubber tire roller added between the steel-wheel breakdown and steel wheel finish rollers. Nuclea...

Evaluation of the use of rubber-tire rollers on asphalt concrete.

DOT National Transportation Integrated Search

1989-01-01

The addition of a rubber-tire roller was required on two projects on maintenance schedules and on two construction projects in 1988. The rubber-tire roller was used as an addition to the conventional rollers on one-half of each project. The rubber-ti...

Hysteroscopic resection on virtual reality simulator: What do we measure?

PubMed

Panel, P; Neveu, M-E; Villain, C; Debras, F; Fernandez, H; Debras, E

2018-06-01

The objective was to compare results of two groups of population (novices and experts) on a virtual reality simulator of hysteroscopy resection for different metrics and for a multimetric score to assess its construct validity. Nineteen gynecologist who had at least 5 years of experience with hysteroscopy and self-evaluated their expertise at 4/5 or 5/5 were included as expert population. Twenty first-year gynecology residents in Paris were included as novice population. A standardized set of 4 hysteroscopy resection cases (polypectomy, myomectomy, roller ball endometrial ablation and septum resection) was performed on a virtual reality simulator (HystSim™) by the group of novices and experts. Results obtained on the simulator for overall score and for the parameters were compared by applying the Mann-Whitney test. Overall score of novices and experts were significantly different for three resection cases (polypectomy P<0.001, myomectomy P<0.001, roller ball endometrial ablation <0.001). The overall score was not different in the septum resection (P=0.456). For the four cases, the economy score (included cumulative path length, procedure time and camera alignment) were statistically different between novices and experts (polypectomy P<0.001, myomectomy P=0.001, roller ball endometrial ablation P<0.001, septum resection P<0.001). The overall score on HystSim™ was able to discriminate novices between experts on polypectomy, myomectomy and roller ball endometrial ablation cases but not on septum resection. The economy score was the more reliable to reflect the surgeon experience. It could be used to evaluate and to train students on hysteroscopic resection on a virtual reality simulator. Copyright © 2018 Elsevier Masson SAS. All rights reserved.

[The noise factor in the manufacture of chocolate and pastry products].

PubMed

Tsvetkov, D; Kalburova, F

1988-01-01

Studies are performed on the noise and vibration condition and hearing in women workers in enterprises for confectionery. It is established that the noise is leading occupational hazard in the working environment and in half of the working places significantly surpasses the sanitary norms and the peak values reach sometimes to 102-105 db/A. Especially intensive sources of noise are some machines and industrial operations-vibratory tables, mixers, cocoa-rollers, grinder for sugar and cocoa, the operation "hammering of forms". The vibrations (general) are rarely met hazard in industry. A considerable decrease of hearing in the examined women workers is established.

Experimental Investigation of Bearing Slip in a Wind Turbine Gearbox During a Transient Grid Loss Event

DOE Office of Scientific and Technical Information (OSTI.GOV)

Helsen, Jan; Guo, Yi; Keller, Jonathan

This work investigates the behaviour of the high speed stage of a wind turbine gearbox during a transient grid loss event. Dynamometer testing on a full scale wind turbine nacelle is used. A combination of external and internal gearbox measurements is analysed. Particular focus is on the characterization of the high speed shaft tapered roller bearing slip behaviour. This slipping behaviour is linked to dynamic events by many researchers and described as potential bearing failure initiator. However only limited full scale dynamic testing is documented. Strain gauge bridges in grooves along the circumference of the outer ring are used tomore » characterize the bearing behaviour in detail. It is shown that during the transient event the high speed shaft experiences a combined torsional and bending deformation. These unfavourable loading conditions induce roller slip in the bearings during the torque reversals indicating the potential of the applied load case to go beyond the preload of the tapered roller bearing.« less

Experimental and numerical study of the effect of rolling parameters on shaft deformation during the longitudinal rolling process

NASA Astrophysics Data System (ADS)

Kowalik, Marek; Trzepiecinski, Tomasz

2018-05-01

This paper presents the characteristics of the process of longitudinal rolling of shafts and the geometry of the working section of forming rollers with a secant profile. In addition, the analytical formulae defining the geometry of a roller profile were determined. The experiments were carried out on shafts made of S235JR and C45 structural steels and the MSC.Marc + Mentat program was used for the numerical analysis of the rolling process based on the finite element method. The paper analyses the effect of roller geometry on the changes in value of the widening coefficient and the diameter reduction coefficient for the first forming passage. It was found that the mechanical properties of the shaft material have a slight influence on the widening coefficient. The value of the widening coefficient of the shaft increases with increase in the initial diameter of the shaft. Increasing shaft diameter causes an increase of strain gradient on the cross-section of the shaft.

High-precision register error control using active-motion-based roller in roll-to-roll gravure printing

NASA Astrophysics Data System (ADS)

Jung, Hoeryong; Nguyen, Ho Anh Duc; Choi, Jaeho; Yim, Hongsik; Shin, Kee-Hyun

2018-05-01

The roll-to-roll (R2R) gravure printing method is increasingly being utilized to fabricate electronic devices such as organic thin-film transistor (OTFT), radio-frequency identification (RFID) tags, and flexible PCB owing to its characteristics of high throughput and large area. High precision registration is crucial to satisfy the demand for device miniaturization, the improvement of resolution and accuracy. This paper presents a novel register control method that uses an active motion-based roller (AMBR) to reduce register error in R2R gravure printing. Instead of shifting the phase of the downstream printing roller, which leads to undesired tension disturbance, the 1 degree-of-freedom (1-DOF) mechanical device AMBR is used to compensate for web elongation by controlling its motion according to the register error. The performance of the proposed control method is verified through simulations and experiments, and the results show that the proposed register control method using the AMBR could maintain a register error under ±15 µm.

Roller to separator contact forces and cage to shaft speed ratios in roller bearings

NASA Technical Reports Server (NTRS)

Nypan, L. J.

1978-01-01

Cage to roller force measurements, cage to shaft speed ratios are reported for 115- and 118-mm bore roller bearings operating at speeds of 4000, 8000, and 12,000 rpm under loads ranging from 360 to 6670 N (80 to 1500 lb).

Roller ginning

USDA-ARS?s Scientific Manuscript database

Roller ginning provided the first mechanical means of separating cotton lint from seed. The first true roller gin was the Churka gin, which was hand operated and consisted of two hard rollers that ran together at the same surface speed, pinching fiber from the seed and producing up to 2.3 kg (5.0 l...

Life analysis of multiroller planetary traction drive

NASA Technical Reports Server (NTRS)

Coy, J. J.; Rohn, D. A.; Loewenthal, S. H.

1981-01-01

A contact fatigue life analysis was performed for a constant ratio, Nasvytis Multiroller Traction Drive. The analysis was based on the Lundberg-Palmgren method for rolling element bearing life prediction. Life adjustment factors for materials, processing, lubrication and traction were included. The 14.7 to 1 ratio drive consisted of a single stage planetary configuration with two rows of stepped planet rollers of five rollers per row, having a roller cluster diameter of approximately 0.21 m, a width of 0.06 m and a weight of 9 kg. Drive system 10 percent life ranged from 18,800 hours at 16.6 kW (22.2 hp) and 25,000 rpm sun roller speed, to 305 hours at maximum operating conditions of 149 kw (200 hp) and 75,000 rpm sun roller speed. The effect of roller diameter and roller center location on life were determined. It was found that an optimum life geometry exists.

Is It More Thrilling to Ride at the Front or the Back of a Roller Coaster?

NASA Astrophysics Data System (ADS)

Alberghi, Stefano; Foschi, Alessandro; Pezzi, Giovanni; Ortolani, Fabio

2007-12-01

An activity called "Project Physics, a Classroom Without Walls" was started during the spring of 2003 at the amusement park in Mirabilandia (Italy). Many thousands of students from Italian middle and high schools are today participating in the initiative. Under the guidance of trained tutors, they perform physics experiments on some of the attractions at the park such as the roller coaster, the Ferris wheel, and the launch towers. The students involved in the experiments can enjoy learning how to observe reality through the eyes of a scientist and to apply classroom concepts to real situations. They discuss the sensations experienced on the rides, perform measurements with traditional and computer-interfaced instruments, analyze collected data, and discuss the results in an open-air physics laboratory. This paper describes the results of one such activity.

48 CFR 252.225-7016 - Restriction on acquisition of ball and roller bearings.

Code of Federal Regulations, 2010 CFR

2010-10-01

... of ball and roller bearings. 252.225-7016 Section 252.225-7016 Federal Acquisition Regulations System... and roller bearings. As prescribed in 225.7009-5, use the following clause: Restriction on Acquisition of Ball and Roller Bearings (MAR 2006) (a) Definitions. As used in this clause' (1) Bearing...

77 FR 45588 - Tapered Roller Bearings and Parts Thereof, Finished and Unfinished, From the People's Republic of...

Federal Register 2010, 2011, 2012, 2013, 2014

2012-08-01

... DEPARTMENT OF COMMERCE International Trade Administration [A-570-601] Tapered Roller Bearings and... new shipper review (``NSR'') of the antidumping duty order on tapered roller bearings from the People... The notice announcing the antidumping duty order on tapered roller bearings from the PRC was published...

76 FR 6397 - Tapered Roller Bearings and Parts Thereof, Finished and Unfinished From the People's Republic of...

Federal Register 2010, 2011, 2012, 2013, 2014

2011-02-04

... DEPARTMENT OF COMMERCE International Trade Administration [A-570-601] Tapered Roller Bearings and... on tapered roller bearings (``TRBs'') from the People's Republic of China (``PRC'') meets the... published in the Federal Register on June 15, 1987. See Antidumping Duty Order; Tapered Roller Bearings and...

76 FR 45777 - Tapered Roller Bearings and Parts Thereof, Finished and Unfinished From the People's Republic of...

Federal Register 2010, 2011, 2012, 2013, 2014

2011-08-01

... DEPARTMENT OF COMMERCE International Trade Administration [A-570-601] Tapered Roller Bearings and... tapered roller bearings (``TRBs'') from the People's Republic of China (``PRC'') meets the statutory and... Register on June 15, 1987. See Antidumping Duty Order; Tapered Roller Bearings and Parts Thereof, Finished...

29 CFR 1918.63 - Chutes, gravity conveyors and rollers.

Code of Federal Regulations, 2014 CFR

2014-07-01

... 29 Labor 7 2014-07-01 2014-07-01 false Chutes, gravity conveyors and rollers. 1918.63 Section 1918... Equipment Other Than Ship's Gear § 1918.63 Chutes, gravity conveyors and rollers. (a) Chutes shall be of... and gravity conveyor roller sections shall be firmly placed and secured to prevent displacement...

29 CFR 1918.63 - Chutes, gravity conveyors and rollers.

Code of Federal Regulations, 2011 CFR

2011-07-01

... 29 Labor 7 2011-07-01 2011-07-01 false Chutes, gravity conveyors and rollers. 1918.63 Section 1918... Equipment Other Than Ship's Gear § 1918.63 Chutes, gravity conveyors and rollers. (a) Chutes shall be of... and gravity conveyor roller sections shall be firmly placed and secured to prevent displacement...

29 CFR 1918.63 - Chutes, gravity conveyors and rollers.

Code of Federal Regulations, 2013 CFR

2013-07-01

... 29 Labor 7 2013-07-01 2013-07-01 false Chutes, gravity conveyors and rollers. 1918.63 Section 1918... Equipment Other Than Ship's Gear § 1918.63 Chutes, gravity conveyors and rollers. (a) Chutes shall be of... and gravity conveyor roller sections shall be firmly placed and secured to prevent displacement...

29 CFR 1918.63 - Chutes, gravity conveyors and rollers.

Code of Federal Regulations, 2012 CFR

2012-07-01

... 29 Labor 7 2012-07-01 2012-07-01 false Chutes, gravity conveyors and rollers. 1918.63 Section 1918... Equipment Other Than Ship's Gear § 1918.63 Chutes, gravity conveyors and rollers. (a) Chutes shall be of... and gravity conveyor roller sections shall be firmly placed and secured to prevent displacement...

29 CFR 1918.63 - Chutes, gravity conveyors and rollers.

Code of Federal Regulations, 2010 CFR

2010-07-01

... 29 Labor 7 2010-07-01 2010-07-01 false Chutes, gravity conveyors and rollers. 1918.63 Section 1918... Equipment Other Than Ship's Gear § 1918.63 Chutes, gravity conveyors and rollers. (a) Chutes shall be of... and gravity conveyor roller sections shall be firmly placed and secured to prevent displacement...

The influence of grip on oxygen consumption and leg forces when using classical style roller skis.

PubMed

Ainegren, M; Carlsson, P; Laaksonen, M S; Tinnsten, M

2014-04-01

The purpose of this study was to investigate the influence of classical style roller skis' grip (static friction coefficients, μS) on cross-country skiers' oxygen consumption and leg forces during treadmill roller skiing, when using the diagonal stride and kick double poling techniques. The study used ratcheted wheel roller skis from the open market and a uniquely designed roller ski with an adjustable camber and grip function. The results showed significantly (P ≤ 0.05) higher oxygen consumption (∼ 14%), heart rate (∼ 7%), and lower propulsive forces from the legs during submaximal exercise and a shorter time to exhaustion (∼ 30%) in incremental maximal tests when using roller skis with a μS similar to on-snow skiing, while there was no difference between tests when using different pairs of roller skis with a similar, higher μS. Thus, we concluded that oxygen consumption (skiing economy), propulsive leg forces, and performance time are highly changed for the worse when using roller skis with a lower μS, such as for on-snow skiing with grip-waxed cross-country skis, in comparison to ratcheted wheel roller skis with several times higher μS. © 2012 John Wiley & Sons A/S. Published by John Wiley & Sons Ltd.

Roller-massager application to the quadriceps and knee-joint range of motion and neuromuscular efficiency during a lunge.

PubMed

Bradbury-Squires, David J; Noftall, Jennifer C; Sullivan, Kathleen M; Behm, David G; Power, Kevin E; Button, Duane C

2015-02-01

Roller massagers are used as a recovery and rehabilitative tool to initiate muscle relaxation and improve range of motion (ROM) and muscular performance. However, research demonstrating such effects is lacking. To determine the effects of applying a roller massager for 20 and 60 seconds on knee-joint ROM and dynamic muscular performance. Randomized controlled clinical trial. University laboratory. Ten recreationally active men (age = 26.6 ± 5.2 years, height = 175.3 ± 4.3 cm, mass = 84.4 ± 8.8 kg). Participants performed 3 randomized experimental conditions separated by 24 to 48 hours. In condition 1 (5 repetitions of 20 seconds) and condition 2 (5 repetitions of 60 seconds), they applied a roller massager to the quadriceps muscles. Condition 3 served as a control condition in which participants sat quietly. Visual analog pain scale, electromyography (EMG) of the vastus lateralis (VL) and biceps femoris during roller massage and lunge, and knee-joint ROM. We found no differences in pain between the 20-second and 60-second roller-massager conditions. During 60 seconds of roller massage, pain was 13.5% (5.7 ± 0.70) and 20.6% (6.2 ± 0.70) greater at 40 seconds and 60 seconds, respectively, than at 20 seconds (P < .05). During roller massage, VL and biceps femoris root mean square (RMS) EMG was 8% and 7%, respectively, of RMS EMG recorded during maximal voluntary isometric contraction. Knee-joint ROM was 10% and 16% greater in the 20-second and 60-second roller-massager conditions, respectively, than the control condition (P < .05). Finally, average lunge VL RMS EMG decreased as roller-massage time increased (P < .05). Roller massage was painful and induced muscle activity, but it increased knee-joint ROM and neuromuscular efficiency during a lunge.

Formation of marine snow and enhanced enzymatic activities in oil-contaminated seawater

NASA Astrophysics Data System (ADS)

Ziervogel, K.; McKay, L.; Yang, T.; Rhodes, B.; Nigro, L.; Gutierrez, T.; Teske, A.; Arnosti, C.

2010-12-01

The fate of oil spilled into the ocean depends on its composition, as well as on biological, chemical, and physical characteristics of the spill site. We investigated the effects of oil addition from the Deepwater Horizon (DH) spill on otherwise uncontaminated water collected close to the spill site. Incubation on a roller table mimicked the physical dynamics of natural seawater, leading to the formation of marine snow-oil aggregates. We measured the enzymatic activities of heterotrophic microbes associated with the aggregates and in the surrounding water, and assessed microbial population and community composition as oil-marine snow aggregates formed and aged in the water. Surface seawater taken near the spill site in May 2010 that had no visible crude oil was incubated in 1-l glass bottles with (oil-bottles) and without (no-oil bottles) a seawater-oil mixture collected from the same site. In the oil-bottles formation of brownish, densely packed marine snow (2-3 cm diameter) was observed within the first hour of the roller table incubation. In contrast no-oil bottles showed aggregate formation only after 3 days, and aggregates were almost transparent, less abundant, and smaller in size (< 1cm diameter). Subsamples of the water surrounding the aggregates were taken throughout 21 days of the roller table incubation, and analyzed for bacterial abundance and community structure as well as the activities of hydrolytic enzymes that are used by heterotrophic bacteria to degrade organic matter. We monitored oil-degrading activities with MUF-stearate and -butyrate, and also measured b-glucosidase, alkaline phosphatase, aminopeptidase, and six different polysaccharide hydrolase activities. Enzymatic activities were up to one order of magnitude higher in the oil-bottles compared with the no-oil bottles throughout the entire incubation time. Butyrate hydrolysis was elevated throughout the time course of the incubation, and stearate hydrolysis was particularly high over the initial 10 days. Activities of enzymes not directly associated with metabolism of oil were also enhanced, however, particularly b-glucosidase, leucine aminopeptidase, and two of the polysaccharide hydrolase activities. These enhanced activities may be a reflection of increased overall microbial metabolism and growth in the oil-bottles, as demonstrated by the 4-fold increase in suspended bacterial cell numbers in oil-bottles over the course of the incubation. Suspended cell numbers in no-oil bottles remained almost unchanged throughout the incubation time. Moreover, aggregates from the oil-bottles were densely colonized by highly active bacteria (5 x 10^9 cells ml-1), one order of magnitude greater than for no-oil aggregates, and two orders of magnitude greater than in the surrounding water. Comparisons of microbial community composition of the oil-bottles and no-oil bottles as well as of the aggregates are currently in progress. Aggregates observed in seawater at the DH spill site likely transport highly active microbial communities to the deeper waters, where they facilitate degradation of deepwater oil.

36 CFR 13.916 - Use of roller skates, skateboards, roller skis, in-line skates, and similar devices.

Code of Federal Regulations, 2010 CFR

2010-07-01

... Public Property NATIONAL PARK SERVICE, DEPARTMENT OF THE INTERIOR NATIONAL PARK SYSTEM UNITS IN ALASKA Special Regulations-Denali National Park and Preserve General Provisions § 13.916 Use of roller skates... 36 Parks, Forests, and Public Property 1 2010-07-01 2010-07-01 false Use of roller skates...

36 CFR 13.916 - Use of roller skates, skateboards, roller skis, in-line skates, and similar devices.

Code of Federal Regulations, 2011 CFR

2011-07-01

... Public Property NATIONAL PARK SERVICE, DEPARTMENT OF THE INTERIOR NATIONAL PARK SYSTEM UNITS IN ALASKA Special Regulations-Denali National Park and Preserve General Provisions § 13.916 Use of roller skates... 36 Parks, Forests, and Public Property 1 2011-07-01 2011-07-01 false Use of roller skates...

36 CFR 13.916 - Use of roller skates, skateboards, roller skis, in-line skates, and similar devices.

Code of Federal Regulations, 2014 CFR

2014-07-01

... Public Property NATIONAL PARK SERVICE, DEPARTMENT OF THE INTERIOR NATIONAL PARK SYSTEM UNITS IN ALASKA Special Regulations-Denali National Park and Preserve General Provisions § 13.916 Use of roller skates... 36 Parks, Forests, and Public Property 1 2014-07-01 2014-07-01 false Use of roller skates...

A Mathematical Roller Derby.

ERIC Educational Resources Information Center

Drucker, Daniel

1992-01-01

Describes an experiment to determine which of four objects, hollow cylinders, solid cylinders, hollow balls, and solid balls, will reach the bottom of an inclined plane first when released simultaneously. Provides solutions to the problem and supplementary exercises. (MDH)

Temperature and Thermal Expansion Analysis of the Cooling Roller Based on the Variable Heat Flux Boundary Condition

NASA Astrophysics Data System (ADS)

Li, Yongkang; Yang, Yang; He, Changyan

2018-04-01

Planar flow casting (PFC) is a primary method for preparing an amorphous ribbon. The qualities of the amorphous ribbon are significantly influenced by the temperature and thermal expansion of the cooling roller. This study proposes a new approach to analyze the three-dimensional temperature and thermal expansion of the cooling roller using variable heat flux that acted on the cooling roller as a boundary condition. First, a simplified two-dimensional model of the PFC is developed to simulate the distribution of the heat flux in the circumferential direction with the software FLUENT. The resulting heat flux is extended to be three-dimensional in the ribbon's width direction. Then, the extended heat flux is imported as the boundary condition by the CFX Expression Language, and the transient temperature of the cooling roller is analyzed in the CFX software. Next, the transient thermal expansion of the cooling roller is simulated through the thermal-structural coupling method. Simulation results show that the roller's temperature and expansion are unevenly distributed, reach the peak value in the middle width direction, and the quasi-steady state of the maximum temperature and thermal expansion are achieved after approximately 50 s and 150 s of casting, respectively. The minimum values of the temperature and expansion are achieved when the roller has a thickness of 45 mm. Finally, the reliability of the approach proposed is verified by measuring the roller's thermal expansion on the spot. This study provides theoretical guidance for the roller's thermal expansion prediction and the gap adjustment in the PFC.

Temperature and Thermal Expansion Analysis of the Cooling Roller Based on the Variable Heat Flux Boundary Condition

NASA Astrophysics Data System (ADS)

Li, Yongkang; Yang, Yang; He, Changyan

2018-06-01

Planar flow casting (PFC) is a primary method for preparing an amorphous ribbon. The qualities of the amorphous ribbon are significantly influenced by the temperature and thermal expansion of the cooling roller. This study proposes a new approach to analyze the three-dimensional temperature and thermal expansion of the cooling roller using variable heat flux that acted on the cooling roller as a boundary condition. First, a simplified two-dimensional model of the PFC is developed to simulate the distribution of the heat flux in the circumferential direction with the software FLUENT. The resulting heat flux is extended to be three-dimensional in the ribbon's width direction. Then, the extended heat flux is imported as the boundary condition by the CFX Expression Language, and the transient temperature of the cooling roller is analyzed in the CFX software. Next, the transient thermal expansion of the cooling roller is simulated through the thermal-structural coupling method. Simulation results show that the roller's temperature and expansion are unevenly distributed, reach the peak value in the middle width direction, and the quasi-steady state of the maximum temperature and thermal expansion are achieved after approximately 50 s and 150 s of casting, respectively. The minimum values of the temperature and expansion are achieved when the roller has a thickness of 45 mm. Finally, the reliability of the approach proposed is verified by measuring the roller's thermal expansion on the spot. This study provides theoretical guidance for the roller's thermal expansion prediction and the gap adjustment in the PFC.

Rib forming tool for tubing

DOEpatents

Rowley, James P.; Lewandowski, Edward F.; Groh, Edward F.

1976-01-01

Three cylindrical rollers are rotatably mounted equidistant from the center of a hollow tool head on radii spaced 120.degree. apart. Each roller has a thin flange; the three flanges lie in a single plane to form an internal circumferential rib in a rotating tubular workpiece. The tool head has two complementary parts with two rollers in one part of the head and one roller in the other part; the two parts are joined by a hinge. A second hinge, located so the rollers are between the two hinges, connects one of the parts to a tool bar mounted in a lathe tool holder. The axes of rotation of both hinges and all three rollers are parallel. A hole exposing equal portions of the three roller flanges is located in the center of the tool head. The two hinges permit the tool head to be opened and rotated slightly downward, taking the roller flanges out of the path of the workpiece which is supported on both ends and rotated by the lathe. The parts of the tool head are then closed on the workpiece so that the flanges are applied to the workpiece and form the rib. The tool is then relocated for forming of the next rib.

Ice-skating and roller disco injuries in Dublin.

PubMed Central

Horner, C.; McCabe, M. J.

1984-01-01

A comparative study was carried out on a series of 72 ice-skating and 57 roller skating injuries over a sixteen month period. The average patient age was 20.5 years in the ice-skating group and 16.5 years in the roller skating group. Females predominated in both groups accounting for 72% of ice-skaters injured and 77% of roller skaters injured. Ice-skaters sustained more serious injuries than roller skaters as was evident from the significant difference in fracture numbers in the two groups. Ice-skating fractures accounted for 40% of all injuries while roller skating fractures were only 14% of their total injuries. The majority of ice-skating fractures occurred in females. As a result of our study we recommended several preventative measures. Images p207-a p207-b PMID:6487948

Multiple rolling/crimping effects on termination of two summer cover crops in a conservation system

USDA-ARS?s Scientific Manuscript database

A field experiment was initiated in the 2015 growing season at the USDA-NSDL to determine the effectiveness of a prototype two-stage roller/crimper in mechanical termination of two summer cover crops intended for organic systems. The experiment was a randomized complete block design with four replic...

Study of rolling element dynamic interactions with separators and raceway paths: Roller to separator contact forces and cage to shaft speed ratios in roller bearings

NASA Technical Reports Server (NTRS)

Nypan, L. J.

1978-01-01

Cage to roller force measurements, cage to shaft forces, and cage to shaft speed ratios are reported for 115 and 118mm bore roller bearings operating at speeds of 4,000, 8,000, and 12,000 rpm under loads ranging from 360 to 6670 N (80 to 1500 lb).

Simulation of roller compaction with subsequent tableting and characterization of lactose and microcrystalline cellulose.

PubMed

Hein, Stephanie; Picker-Freyer, Katharina M; Langridge, John

2008-01-01

Tablets are by far the most common solid oral dosage forms, and many drugs need to be granulated before they can be tableted. Increasingly roller compaction is being used as a dry granulation technique; however it is a very time and material intensive method. Thus some mini roller compactors and simulations of the roller compaction process have been developed as a means of studying the technique at small scale. An important factor in the selection of materials for roller compaction is their ability to be recompressed into tablets after the initial roller compaction and milling steps. In this paper the roller compaction process was simulated on the basis of some models by Gereg and Cappola (2002) and Zinchuk et al. (2004). An eccentric tableting machine was used to make compacts from alpha-lactose monohydrate, anhydrous beta-lactose, spray-dried lactose and microcrystalline cellulose at different maximum relative densities (rho rel,max 0.6-0.9). These compacts were milled immediately to granules with a rotary granulator. The properties of the granules were analyzed and compared to the properties of the original powders. These granules and powders were then tableted at different maximum relative densities (rho rel,max 0.75-0.95) and their properties including elastic recovery, crushing force and 3D-model were analyzed. The properties of the tablets made from the granules were compared to the properties of the tablets made from the powders to determine which excipients are most suitable for the roller compaction process. The study showed that anhydrous beta-lactose is the preferred form of lactose for use in roller compaction since compaction did not affect tablet crushing force to a large extent. With the simulation of roller compaction process one is able to find qualified materials for use in roller compaction without the necessity of a great deal of material and time.

Lateral Stability Simulation of a Rail Truck on Roller Rig

NASA Astrophysics Data System (ADS)

Dukkipati, Rao V.

The development of experimental facilities for rail vehicle testing 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 development of the Roller Rigs and to establish an analytic framework for the design and interpretation of tests to be conducted on Roller Rigs. The work described here represents initial efforts towards meeting these objectives. Generic linear models were developed of a freight car (with a characteristic North American three-piece truck) on tangent track. The models were developed using the generalized multi body dynamics software MEDYNA. Predictions were made of the theoretical linear model hunting (lateral stability) characteristics of the freight car, i. e., the critical speeds and frequencies, for five different configurations: (a) freight car on track, (b) the freight car's front truck on the roller stand and its rear truck on track, (c) freight car on the roller rig, (d) a single truck on track, and (e) single truck on the roller stand. These were compared with the Association of American Railroads' field test data for an 80-ton hopper car equipped with A-3 ride control trucks. Agreement was reached among all the analytical models, with all models indicating a range of hunting speeds of 2% from the highest to lowest. The largest discrepancy, approximately 6%, was indicated between the models and the field test data. Parametric study results using linear model of freight truck on the roller rig show 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 destabilizing 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.

Vibratory roller study.

DOT National Transportation Integrated Search

1984-01-01

Recently, much criticism has been directed toward the use of vibratory rollers to compact bituminous concrete. The results of the study reported here indicate that when these rollers are operated properly they can produce dense, strong, smooth riding...

Preliminary Comparison of 17- and 75-millimeter-bore Cageless Cylindrical Roller Bearings with Conventional Cylindrical Roller Bearings at High Speeds

NASA Technical Reports Server (NTRS)

Macks, E Fred; Anderson, W J; Nemeth, Zolton N

1953-01-01

Preliminary results at high speeds indicate lower bearing temperatures, less internal bearing wear, and greater reliability of the conventional, cage-type cylindrical roller bearings than of either full-complement or special cageless roller bearings of the types investigated, although the latter bearing types have been operated successfully to DN values of 1.0 X 10 superscript 6.

Ecology of the Sand Roller (Percopsis transmontana) in a lower Snake River Reservoir, Washington

USGS Publications Warehouse

Tiffan, Kenneth F.; Erhardt, John M.; Rhodes, Tobyn N.; Hemingway, Rulon J.

2017-01-01

The Sand Roller (Percopsis transmontana), has not been abundant in the Snake River since it was first found in the system in the 1950s, but its population has apparently increased in recent years. As a result, we initiated a study to better understand its ecology in habitats of Lower Granite Reservoir. From November 2014 to October 2015, Sand Rollers were present along shorelines, with peak abundance being observed during spring months. Logistic regression analyses showed that Sand Rollers were more likely to be present in shoreline habitats at temperatures ≤18.4°C. Fish were found over a range of substrates, with the lowest odds of fish presence being associated with riprap, which is common in hydropower reservoirs. From length-frequency analysis, we suggest that Sand Roller spawning occurs primarily in May and early June. Assessment of Sand Roller diets found dipteran (chironomid) larvae and pupae were the most important prey consumed by all sizes of Sand Rollers, but Opossum Shrimp (Neomysis mercedis) were also prominent in diets of larger fish in shoreline and offshore habitats. At a time when the populations of so many native species are in decline, the increase of the Sand Roller population in the lower Snake River represents a positive, yet curious occurrence.

Quincke random walkers

NASA Astrophysics Data System (ADS)

Pradillo, Gerardo; Heintz, Aneesh; Vlahovska, Petia

2017-11-01

The spontaneous rotation of a sphere in an applied uniform DC electric field (Quincke effect) has been utilized to engineer self-propelled particles: if the sphere is initially resting on a surface, it rolls. The Quincke rollers have been widely used as a model system to study collective behavior in ``active'' suspensions. If the applied field is DC, an isolated Quincke roller follows a straight line trajectory. In this talk, we discuss the design of a Quincke roller that executes a random-walk-like behavior. We utilize AC field - upon reversal of the field direction a fluctuation in the axis of rotation (which is degenerate in the plane perpendicular to the field and parallel to the surface) introduces randomness in the direction of motion. The MSD of an isolated Quincke walker depends on frequency, amplitude, and waveform of the electric field. Experiment and theory are compared. We also investigate the collective behavior of Quincke walkers,the transport of inert particles in a bath of Quincke walkers, and the spontaneous motion of a drop containing Quincke active particle. supported by NSF Grant CBET 1437545.

Kinematic stability of roller pairs in free rolling contact

NASA Technical Reports Server (NTRS)

Savage, M.; Loewenthal, S. H.

1976-01-01

A set of generalized stability equations was developed for roller pairs in free rolling contact. A symmetric, dual contact model was used. Four possible external contact profiles that possess continuous contacting surfaces were studied. It was found that kinematic stability would be insured if the larger radius of transverse curvature, in absolute value, and the smaller rolling radius both exist on the roller that has the apex of its conical surface outboard of its main body. The stability criteria developed are considered to be useful for assessing axial restraint requirements for a variety of roller mechanisms and in the selection of roller contact geometry for traction drive devices.

Roller compacted concrete : field evaluation and mixture optimization.

DOT National Transportation Integrated Search

2014-08-01

Roller Compacted Concrete (RCC) as an economical, fast construction and sustainable materials has attracted increasing attention for pavement construction. The growth of roller-compacted concrete pavement used in different regions is impeded by conce...

48 CFR 225.7009 - Restriction on ball and roller bearings.

Code of Federal Regulations, 2010 CFR

2010-10-01

... 48 Federal Acquisition Regulations System 3 2010-10-01 2010-10-01 false Restriction on ball and roller bearings. 225.7009 Section 225.7009 Federal Acquisition Regulations System DEFENSE ACQUISITION... roller bearings. ...

Une Experience d'enseignement programme de la grammaire francaise (An Experiment in Programed Instruction of French Grammar).

ERIC Educational Resources Information Center

Girard, Jacques D.

An experiment is reported involving the teaching of the agreement of the past participle without an auxiliary verb, with "avoir" and with "etre," patterned after the studies of S. Roller in 1952-53 in this area. The initial experimentation is updated and involves the use of a Skinnerian model of programed instruction. The objectives, operational…

Roller-compacted concrete pavements.

DOT National Transportation Integrated Search

2010-09-01

Roller-compacted concrete (RCC) gets its name from the heavy vibratory steel drum and rubber-tired rollers used to help compact it into its final form. RCC has similar strength properties and consists of the same basic ingredients as conventional con...

Vibratory roller evaluation study : final report.

DOT National Transportation Integrated Search

1976-03-01

The Louisiana Department of Highways has recently completed a program to evaluate the use of vibratory rollers in the compaction of asphaltic concrete pavements. In all, a total of nine different vibratory rollers was tested along with conventional s...

The 1982 epidemic--roller skating injuries.

PubMed Central

Bunker, T. D.

1983-01-01

A series of 100 roller skating injuries is presented. Roller skating injuries have been occurring at a higher rate than the previously reported skateboarding epidemic of 1977. The severity of injury has been lower, 32% fractures and dislocations occurring whilst roller skating, compared to 60% whilst skateboarding. In particular a striking reduction is seen in ankle fractures. Fifty questionnaires detailing method of injury were analysed. Images p205-a Fig. 1 Fig. 2 PMID:6652406

Increasing the Energy Efficiency of the Cyclic Action Mechanisms in Rolling for a Roller Bed Used as an Example

NASA Astrophysics Data System (ADS)

andreev, A. N.; Kolesnichenko, D. A.

2017-12-01

The possibility of increasing the energy efficiency of the production cycle in a roller bed is briefly reviewed and justified. The sequence diagram of operation of the electrical drive in a roller bed is analyzed, and the possible increase in the energy efficiency is calculated. A method for energy saving is described for the application of a frequency-controlled asynchronous electrical drive of drive rollers in a roller bed with an increased capacitor capacity in a dc link. A fine mathematical model is developed to describe the behavior of the electrical drive during the deceleration of a roller bed. An experimental setup is created and computer simulation and physical modeling are performed. The basic information flows of the general hierarchical automatic control system of an enterprise are described and determined with allowance for the proposed method of increasing the energy efficiency.

The Dramaturg as Professor: Riding the Roller Coaster of Authority in Linking a Seminar to a Production.

ERIC Educational Resources Information Center

Nouryeh, Andrea J.

2001-01-01

Outlines a team-teaching experiment between a director and dramaturg which was linked to a production of Caryl Churchill's "Cloud Nine." Investigates aesthetic choices, gender identity and sexuality that the play raises. Notes the problems in this arrangement and suggests that engaging in this kind of pedagogical experiment demands much…

Development of an aerostatic bearing system for roll-to-roll printed electronics

NASA Astrophysics Data System (ADS)

Chen, Shasha; Chen, Weihai; Liu, Jingmeng; Chen, Wenjie; Jin, Yan

2018-06-01

Roll-to-roll printed electronics is proved to be an effective way to fabricate electrical devices on various substrates. High precision overlay alignment plays a key role to create multi-layer electrical devices. Multiple rollers are adopted to support and transport the substrate web. In order to eliminate the negative effect of the machining error and assembling error of the roller, a whole roll-to-roll system including two aerostatic bearing devices with arrayed restrictors is proposed in this paper. Different to the conventional roller, the aerostatic bearing device can create a layer of air film between the web and the device to realize non-contact support and transport. Based on simplified Navier–Stokes equations, the theoretical model of the air film is established. Moreover, the pressure distribution of the whole flow field and single restrictor in different positions are modeled by conducting numerical simulation with computational fluid dynamics (CFD) software FLUENT. The load capacity curves and stiffness curves are generated to provide guidance for optimizing the structure of the device. A prototype of the aerostatic bearing system is set up and the experiment tests are carried out. For the proposed aerostatic bearing roller with a diameter of 100 mm and length of 200 mm, the experimental results show the aerostatic bearing method can achieve the position accuracy in a range of 1 μm in the vertical direction of the web, which is much better than that using existing methods.

Roller Compacted Concrete over Soil Cement under Accelerated Loading : Research Project Capsule

DOT National Transportation Integrated Search

2012-09-01

Roller compacted concrete (RCC) is a stiff , zero-slump concrete mixture placed with modifi ed : asphalt paving equipment and compacted by vibratory rollers. Properly designed RCC mixes : can achieve outstanding compressive strengths similar to those...

Space Shuttle Orbiter Atlantis Liquid Oxygen Prevalve Detent Roller Cracking Investigation

NASA Technical Reports Server (NTRS)

Holleman, Elizabeth; Eddleman, David; Richard, James; Jacobs, Rebecca

2008-01-01

During routine inspections of the Space Shuttle's Main Propulsion System (MPS) Liquid Oxygen (LO2) pre-valve, the mechanism provided to maintain the valve in the open position was found cracked. The mechanism is a Vespel roller held against the valve visor by a stack of Belleville springs. The roller has been found cracked 3 times. All three instances were in the same valve in the same location. There are 6 pre-valves on each orbiter, and only one has exhibited this problem. Every-flight inspections were instituted and the rollers were found to be cracked after only one flight. Engineers at Marshall Space Flight Center, Johnson Space Center and Kennedy Space Center worked together to determine a solution. There were several possible contributors to the failure: a mis-aligned visor, an out of specification edge with a sharp radius, an out of specification tolerance stack up of a Belleville spring stack that caused un-predicted loads on the Vespel SP-21 roller, and a dimple machined into the side of the roller to indicate LO2 compatibility that created a stress riser. The detent assembly was removed and replaced with parts that were on the low-side of the tolerance stack up to eliminate the potential for high loads on the detent roller. After one flight, the roller was inspected and showed fewer signs of wear and no cracks.

Space Shuttle Orbiter Atlantis Liquid Oxygen Pre-Valve Detent Roller Cracking Investigation

NASA Technical Reports Server (NTRS)

Holleman, Elizabeth; Eddleman, David; Jacobs, Rebecca; Richard, James

2008-01-01

During routine inspections of the Space Shuttle s Main Propulsion System Liquid Oxygen (LO2) pre-valve, the mechanism provided to maintain the valve in the open position was found cracked. The mechanism is a Vespel roller held against the valve visor by a stack of Belleville springs. The roller has been found cracked 3 times. All three instances were in the same valve in the same location. There are 6 pre-valves on each orbiter, and only one has exhibited this problem. Every-flight inspections were instituted and the rollers were found to be cracked after only one flight. Engineers at Marshall Space Flight Center, Johnson Space Center, and Kennedy Space Center worked together to determine a solution. There were several possible contributors to the failure: a misaligned visor, an out-of-specification edge with a sharp radius, an out-of-specification tolerance stack up of a Belleville spring stack that caused un-predicted loads on the Vespel SP-21 roller, and a dimple machined into the side of the roller to indicate LO2 compatibility that created a stress riser. The detent assembly was removed and replaced with parts that were on the low side of the tolerance stack up to eliminate the potential for high loads on the detent roller. After one flight, the roller was inspected and showed fewer signs of wear and no cracks.

Improvement of Railroad Roller Bearing Test Procedures & Development of Roller Bearing Diagnostic Techniques. Volume 2.

DOT National Transportation Integrated Search

1982-04-01

A comprehensive review of existing basic diagnostic techniques applicable to the railcar roller bearing defect and failure problem was made. Of the potentially feasible diagnostic techniques identified, high frequency vibration was selected for exper...

Improving feeding powder distribution to the compaction zone in the roller compaction.

PubMed

Yu, Mingzhe; Omar, Chalak; Schmidt, Alexander; Litster, James D; Salman, Agba D

2018-07-01

In the roller compaction process, powder flow properties have a significant influence on the uniformity of the ribbon properties. The objective of this work was to improve the powder flow in the feeding zone by developing novel feeding guiders which are located in the feeding zone close to the rollers in the roller compactor (side sealing system). Three novel feeding guiders were designed by 3D printing and used in the roller compactor, aiming to control the amount of powder passing across the roller width. The new feeding guiders were used to guide more powder to the sides between the rollers and less powder to the centre comparing to the original feeding elements. Temperature profile and porosity across the ribbon width indicated the uniformity of the ribbon properties. Using the novel feeding guiders resulted in producing ribbons with uniform temperature profile and porosity distribution across the ribbon width. The design of the feeding guiders contributed to improving the tensile strength of the ribbons produced from the compaction stage as well as reducing the fines produced from the crushing stage. Copyright © 2018 Elsevier B.V. All rights reserved.

A study on rheological characteristics of roller milled fenugreek fractions.

PubMed

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.

Finite element estimation of the residual stresses in roller-straightened rail

DOT National Transportation Integrated Search

2004-11-13

The purpose of this paper is to develop models to accurately predict : the residual stresses due to the roller straightening of railroad rails. : Several aspects of residual stress creation in rail due to roller : straightening are addressed. The eff...

Depreciation of bearing blocks of rollers of roller conveyers of rolling mills

NASA Astrophysics Data System (ADS)

Artiukh, Viktor; Belyaev, Michael; Ignatovich, Igor; Miloradova, Nadezda

2017-10-01

Essential increase in functional durability of a node of a roller of the roller conveyer of the rolling mill by the rational choice of parameters of the small-size shock-absorber (buffer adapter) is shown. At the same time dimensions of a node don’t change, costs of reconstruction are small. The possibility of management of loadings in a bearing node without change of technology parameters of the process which is carried out by the rolling mill is confirmed.

Parametric analysis of plastic strain and force distribution in single pass metal spinning

NASA Astrophysics Data System (ADS)

Choudhary, Shashank; Tejesh, Chiruvolu Mohan; Regalla, Srinivasa Prakash; Suresh, Kurra

2013-12-01

Metal spinning also known as spin forming is one of the sheet metal working processes by which an axis-symmetric part can be formed from a flat sheet metal blank. Parts are produced by pressing a blunt edged tool or roller on to the blank which in turn is mounted on a rotating mandrel. This paper discusses about the setting up a 3-D finite element simulation of single pass metal spinning in LS-Dyna. Four parameters were considered namely blank thickness, roller nose radius, feed ratio and mandrel speed and the variation in forces and plastic strain were analysed using the full-factorial design of experiments (DOE) method of simulation experiments. For some of these DOE runs, physical experiments on extra deep drawing (EDD) sheet metal were carried out using En31 tool on a lathe machine. Simulation results are able to predict the zone of unsafe thinning in the sheet and high forming forces that are hint to the necessity for less-expensive and semi-automated machine tools to help the household and small scale spinning workers widely prevalent in India.

Investigation of roller-compacted concrete for use in pavements in Virginia.

DOT National Transportation Integrated Search

2016-12-01

Roller-compacted concrete (RCC) is a stiff mixture of aggregate, cementitious materials, and water with zero slump. RCC : is consolidated or compacted in the fresh state by use of a roller with or without vibration. RCC typically is placed with aspha...

Method and apparatus to control the lateral motion of a long metal bar being formed by a mechanical process such as rolling or drawing

DOEpatents

Chang, Tzyy-Shuh [Ann Arbor, MI; Huang, Hsun-Hau [Ann Arbor, MI; Lin, Chang-Hung [Ypsilanti, MI

2011-01-04

An apparatus to control lateral motion of a bar moving along a guidance path includes a pair of rotatable hubs each having at least first and second rollers at locations around the perimeter of the hub. The first roller has a first retaining groove of a first radius and the second roller has a second groove of a second radius smaller than the first radius. Each hub further includes at least one guiding element located between the rollers with a guide channel extending in the outer surface. A mounting system allows the hubs to be rotated between first and second positions. In the first position the first rollers oppose each other forming a guideway having a first, enlarged diameter for capturing a free end of an approaching bar. In the second position the second rollers form a second, smaller diameter to match the actual size of the bar.

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

NASA Technical Reports Server (NTRS)

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.

Improvement of Railroad Roller Bearing Test Procedures & Development of Roller Bearing Diagnostic Techniques. Volume 1.

DOT National Transportation Integrated Search

1982-03-01

Bearing defect data from 8,000 railroad roller bearings are analyzed to determine their defect modes and defect rate distributions. Cone bore growth, brinelling, and fatigue are identified as the predominant defect modes during the first 12 years of ...

49 CFR 215.115 - Defective roller bearing.

Code of Federal Regulations, 2010 CFR

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— (i...

49 CFR 215.115 - Defective roller bearing.

Code of Federal Regulations, 2013 CFR

2013-10-01

..., 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— (i...

49 CFR 215.115 - Defective roller bearing.

Code of Federal Regulations, 2011 CFR

2011-10-01

..., 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— (i...

49 CFR 215.115 - Defective roller bearing.

Code of Federal Regulations, 2014 CFR

2014-10-01

..., 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— (i...

49 CFR 215.115 - Defective roller bearing.

Code of Federal Regulations, 2012 CFR

2012-10-01

..., 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— (i...

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

Federal Register 2010, 2011, 2012, 2013, 2014

2012-02-29

... INTERNATIONAL TRADE COMMISSION [Investigation No. 731-TA-344 (Third Review)] Tapered Roller Bearings From China; Scheduling of a Full Five- Year Review AGENCY: United States International Trade... whether revocation of the antidumping duty order on tapered roller bearings from China would be likely to...

77 FR 45587 - Tapered Roller Bearings and Parts Thereof, Finished and Unfinished, from the People's Republic of...

Federal Register 2010, 2011, 2012, 2013, 2014

2012-08-01

... DEPARTMENT OF COMMERCE International Trade Administration [A-570-601] Tapered Roller Bearings and... new shipper review (``NSR'') of the antidumping duty order on tapered roller bearings (``TRBs'') from... from Zhejiang Zhengda Bearing Co., Ltd. (``Zhejiang Zhengda''). Zhejiang Zhengda's request was made in...

Continuous overturn control of compactors/rollers by rollover protective structures

PubMed Central

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

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

PubMed Central

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

2015-01-01

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. PMID:26473858

Effects of glovebox gloves on grip and key pinch strength and contact forces for simulated manual operations with three commonly used hand tools.

PubMed

Sung, Peng-Cheng

2014-01-01

This study examined the effects of glovebox gloves for 11 females on maximum grip and key pinch strength and on contact forces generated from simulated tasks of a roller, a pair of tweezers and a crescent wrench. The independent variables were gloves fabricated of butyl, CSM/hypalon and neoprene materials; two glove thicknesses; and layers of gloves worn including single, double and triple gloving. CSM/hypalon and butyl gloves produced greater grip strength than the neoprene gloves. CSM/hypalon gloves also lowered contact forces for roller and wrench tasks. Single gloving and thin gloves improved hand strength performances. However, triple layers lowered contact forces for all tasks. Based on the evaluating results, selection and design recommendations of gloves for three hand tools were provided to minimise the effects on hand strength and optimise protection of the palmar hand in glovebox environments. To improve safety and health in the glovebox environments where gloves usage is a necessity, this study provides recommendations for selection and design of glovebox gloves for three hand tools including a roller, a pair of tweezers and a crescent wrench based on the results discovered in the experiments.

Adhesive Wear of Rollers in Vacuum

NASA Technical Reports Server (NTRS)

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

Sensing roller for in-process thickness measurement

DOEpatents

Novak, James L.

1996-01-01

An apparatus and method for processing materials by sensing roller, in which the sensing roller has a plurality of conductive rings (electrodes) separated by rings of dielectric material. Sensing capacitances or impedances between the electrodes provides information on thicknesses of the materials being processed, location of wires therein, and other like characteristics of the materials.

76 FR 72213 - Tapered Roller Bearings From China; Notice of Commission determination To Conduct a Full Five...

Federal Register 2010, 2011, 2012, 2013, 2014

2011-11-22

... INTERNATIONAL TRADE COMMISSION [Investigation No. 731-TA-344 (Third Review)] Tapered Roller Bearings From China; Notice of Commission determination To Conduct a Full Five-Year Review AGENCY: United...(c)(5)) to determine whether revocation of the antidumping duty order on tapered roller bearings from...

78 FR 45912 - Tapered Roller Bearings and Parts Thereof, Finished and Unfinished, From the People's Republic of...

Federal Register 2010, 2011, 2012, 2013, 2014

2013-07-30

... DEPARTMENT OF COMMERCE International Trade Administration [A-570-601] Tapered Roller Bearings and... Bearing Co., Ltd.'s (Tainai's) request for a new shipper review (NSR) of the antidumping duty order on tapered roller bearings and parts thereof, finished and unfinished (TRBs), from the People's Republic of...

Electromagnetic brake/clutch device

NASA Technical Reports Server (NTRS)

Vranish, John M. (Inventor)

1994-01-01

An electromagnetic brake/clutch device includes a drive shaft supported by at least one bearing for transmitting torque, a housing, affixed to prevent its rotation, surrounding the drive shaft, and an electromagnetically activated device within the housing to selectively prevent and allow rotation of the drive shaft. The electromagnetically activated device includes a plurality of cammed rollers to prevent counter-clockwise rotation of the drive shaft. The drive shaft includes a circumferential disk and the housing includes a reaction ring for engagement with the plurality of cammed rollers. The plurality of cammed rollers are released from engagement with the circumferential disk and the reaction ring by a plurality of tripping mechanisms within the housing. The tripping action uses the locking force to act as a release force merely by changing the boundary conditions of the roller interface angles. The tripping mechanisms include trippers for disengaging the plurality of cammed rollers and an anvil shaped portion for providing lateral movement of the trippers. The plurality of cammed rollers is preloaded to engagement with the circumferential disk and reaction ring by a spring, and is located with respect to an adjacent tripping mechanism with another spring.

Partial tooth gear bearings

NASA Technical Reports Server (NTRS)

Vranish, John M. (Inventor)

2010-01-01

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

Termination of cover crops using rollers/crimpers

USDA-ARS?s Scientific Manuscript database

An integral component of conservation agriculture systems is the use of a high-residue winter cover crop; however, terminating cover crops is an addition expense and planting into high-residue can be a challenge. An experiment was conducted using black oat (Avena strigosa Schreb.), rye (Secale cere...

Anthropometric and somatotype characteristics of world class male roller skaters by discipline.

PubMed

Vila, H; Abraldes, J A; Rodríguez, N; Ferragut, C

2015-01-01

The aim of this study was twofold: 1) to describe the anthropometric profile and somatotype of the elite male roller skaters; and: 2) to assess if there are any differences in these items by roller skating discipline (figures, freestyle, pair and dance). Eighty-eight male skater participants in the 51st Figure Roller Skating World Championship were selected for the study. The International Society for the Advancement of Kinanthropometry (ISAK) protocol was used to determine the anthropometric profile of the figure skaters. Additionally, Body Mass Index (BMI), sum of four and six skinfolds and somatotype were also analysed. No significant differences were found for the sum of four and six skinfolds among disciplines. Significant differences were found for flexed arm (P≤0.05), forearm (P≤0.05) and wrist girths (P≤0.001) between artistic roller figure and pair skaters. Significant differences were found in waist girth (P≤0.05), flexed arm, forearm and wrist girths (P≤0.001) between artistic roller freestyle and pairs skaters. No differences were found in lower limbs girths among disciplines. Significant differences were found in humerus (P<0.05) and bistyloid (P<0.05) breadth among disciplines. The general somatotype is endo-mesomorphic for roller freestyle and figure skaters. In pair skaters the somatotype is ecto-mesomorphic, and for dance skaters it is balanced mesomorphic.

Sensing roller for in-process thickness measurement

DOEpatents

Novak, J.L.

1996-07-16

An apparatus and method are disclosed for processing materials by sensing roller, in which the sensing roller has a plurality of conductive rings (electrodes) separated by rings of dielectric material. Sensing capacitances or impedances between the electrodes provides information on thicknesses of the materials being processed, location of wires therein, and other like characteristics of the materials. 6 figs.

United States Air Force Analysis Extract AFSC 2A6X4 Aircraft Fuel Systems (Active Duty)

DTIC Science & Technology

2001-02-01

8217AFOMS (AETC) Randolph AFB TX’ V0226 Spec tools/equip use/oper - Rollers or Stitchers ACTIVE...8217AFOMS (AETC) Randolph AFB TX’ V0226 Spec tools/equip use/oper - Rollers or Stitchers ...equip use/oper - Rollers or Stitchers USAFE AETC PACAF AFSOC ACC AMC AFMC

United States Air Force Analysis Extract AFSC 2A6X4 Aircraft Fuel Systems (ANG/AFRC)

DTIC Science & Technology

2001-02-01

8217AFOMS (AETC) Randolph AFB TX’ V0226 Spec tools/equip use/oper - Rollers or Stitchers ...8217 V0226 Spec tools/equip use/oper - Rollers or Stitchers ANG ANG ANG RES RES...8217AFOMS (AETC) Randolph AFB TX’ V0226 Spec tools/equip use/oper - Rollers or Stitchers

78 FR 3396 - Tapered Roller Bearings and Parts Thereof, Finished and Unfinished, From the People's Republic of...

Federal Register 2010, 2011, 2012, 2013, 2014

2013-01-16

... pillow blocks) incorporating tapered rollers, with or without spindles, whether or not for automotive use... JTEKT (Thailand) Co., Ltd. We valued CPZ/SKF's roller steel using Harmonized Tariff Schedule (``HTS... circular cross- section''), rather than HTS category 7227.90 (``Bars and rods of alloy steel (other than...

A weed compaction roller system for use with mechanical herbicide application

Treesearch

Adam H. Wiese; Daniel A. Netzer; Don E. Riemenschneider; Ronald S., Jr. Zalesny

2006-01-01

We designed, constructed, and field-tested a versatile and unique weed compaction roller system that can be used with mechanical herbicide application for invasive weed control in tree plantations, agronomic settings, and areas where localized flora and fauna are in danger of elimination from the landscape. The weed compaction roller system combined with herbicide...

Validation of a Functional Pyelocalyceal Renal Model for the Evaluation of Renal Calculi Passage While Riding a Roller Coaster.

PubMed

Mitchell, Marc A; Wartinger, David D

2016-10-01

The identification and evaluation of activities capable of dislodging calyceal renal calculi require a patient surrogate or validated functional pyelocalyceal renal model. To evaluate roller coaster facilitation of calyceal renal calculi passage using a functional pyelocalyceal renal model. A previously described adult ureteroscopy and renoscopy simulator (Ideal Anatomic) was modified and remolded to function as a patient surrogate. Three renal calculi of different sizes from the patient who provided the original computed tomographic urograph on which the simulator was based were used. The renal calculi were suspended in urine in the model and taken for 20 rides on the Big Thunder Mountain Railroad roller coaster at Walt Disney World in Orlando, Florida. The roller coaster rides were analyzed using variables of renal calculi volume, calyceal location, model position on the roller coaster, and renal calculi passage. Sixty renal calculi rides were analyzed. Independent of renal calculi volume and calyceal location, front seating on the roller coaster resulted in a passage rate of 4 of 24. Independent of renal calculi volume and calyceal location, rear seating on the roller coaster resulted in a passage rate of 23 of 36. Independent of renal calculi volume in rear seating, calyceal location differed in passage rates, with an upper calyceal calculi passage rate of 100%; a middle calyceal passage rate of 55.6%; and a lower calyceal passage rate of 40.0%. The functional pyelocalyceal renal model serves as a functional patient surrogate to evaluate activities that facilitate calyceal renal calculi passage. The rear seating position on the roller coaster led to the most renal calculi passages.

Cost of a roller skating rink to the local accident and emergency department.

PubMed Central

Nayeem, N; Shires, S E; Porter, J E

1990-01-01

A 14 month retrospective study was undertaken to determine the cost implications of the opening of a roller skating rink to the local hospital accident and emergency department (A and E). A total of 398 patients attended following injury at the roller skating rink, of whom 384 were included in the study. The estimated cost of their injuries was determined by the hospital accounts department. The average cost per patient attending the A and E department following roller skating injury was about 100 pounds. The total cost to the A and E department of all injuries sustained at the rink over this period was 38,412 pounds. The cost implications of opening a roller skating rink for the A and E department are considerable. If proposals for self-budgeting are applied, A and E departments will have to seek additional funding if such leisure facilities are opened in their vicinity. PMID:2097020

Reduced-tillage organic corn production in a hairy vetch cover crop

USDA-ARS?s Scientific Manuscript database

There is much interest in developing no-tillage systems for organic farming, however, potential limitations include the inability to control weeds and to provide sufficient crop available N. A three-year field experiment was conducted on organically-certified land to explore the use of roller-crimp...

Oak leaf roller: contact toxicity of four insecticides applied to the larvae

Treesearch

Lula E. Greene; Marion Page

1974-01-01

A defoliator of oak and witch-hazel, the oak leaf roller (Archips semiferanus [Walker]) is found in large numbers in northeastern United States and in southwest Ontario, Canada. DDT was formerly used to control this insect. As a preliminary step in finding alternatives to DDT for field testing against the oak leaf roller, four insecticides were...

Effects of different roller/crimper designs and rolling speed on rye cover crop termination and seedcotton yield in A no-till system

USDA-ARS?s Scientific Manuscript database

Rollers/crimpers have been utilized in no-till systems to mechanically terminate cover crops as a substitute for chemical termination; however, excessive vibration generated by the original straight bar roller adopted from Brazil has delayed its adoption in the U.S. To reduce excessive vibration, pr...

The System of Simulation and Multi-objective Optimization for the Roller Kiln

NASA Astrophysics Data System (ADS)

Huang, He; Chen, Xishen; Li, Wugang; Li, Zhuoqiu

It is somewhat a difficult researching problem, to get the building parameters of the ceramic roller kiln simulation model. A system integrated of evolutionary algorithms (PSO, DE and DEPSO) and computational fluid dynamics (CFD), is proposed to solve the problem. And the temperature field uniformity and the environment disruption are studied in this paper. With the help of the efficient parallel calculation, the ceramic roller kiln temperature field uniformity and the NOx emissions field have been researched in the system at the same time. A multi-objective optimization example of the industrial roller kiln proves that the system is of excellent parameter exploration capability.

Development of small bore, high speed tapered roller bearing

NASA Technical Reports Server (NTRS)

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.

Effect of Roller Profile on Cylindrical Roller Bearing Life Prediction

NASA Technical Reports Server (NTRS)

Poplawski, Joseph V.; Zaretsky, Erwin V.; Peters, Steven M.

2000-01-01

Four roller profiles used in cylindrical roller bearing design and manufacture were analyzed using both a closed form solution and finite element analysis (FEA) for stress and life. The roller profiles analyzed were flat, tapered end, aerospace, and fully crowned loaded against a flat raceway. Four rolling-element bearing life models were chosen for this analysis and compared. These were those of Weibull, Lundberg and Palmgren, Ioannides and Harris, and Zaretsky. The flat roller profile without edge loading has the longest predicted life. However, edge loading can reduce life by as much as 98 percent. The end tapered profile produced the highest lives but not significantly different than the aerospace profile. The fully crowned profile produces the lowest lives. The resultant predicted life at each stress condition not only depends on the life equation used but also on the Weibull slope assumed. For Weibull slopes of 1.5 and 2, both Lundberg-Palmgren and Iaonnides-Harris equations predict lower lives than the ANSI/ABMAJISO standards. Based upon the Hertz stresses for line contact, the accepted load-life exponent of 10/3 results in a maximum Hertz stress-life exponent equal to 6.6. This value is inconsistent with that experienced in the field.

Assessment of solid microneedle rollers to enhance transmembrane delivery of doxycycline and inhibition of MMP activity.

PubMed

Omolu, Abbie; Bailly, Maryse; Day, Richard M

2017-11-01

Many chronic wounds exhibit high matrix metalloproteinase (MMP) activity that impedes the normal wound healing process. Intradermal delivery (IDD) of sub-antimicrobial concentrations of doxycycline, as an MMP inhibitor, could target early stages of chronic wound development and inhibit further wound progression. To deliver doxycycline intradermally, the skin barrier must be disrupted. Microneedle rollers offer a minimally invasive technique to penetrate the skin by creating multiple microchannels that act as temporary conduits for drugs to diffuse through. In this study, an innovative and facile approach for delivery of doxycycline across Strat-M TM membrane was investigated using microneedle rollers. The quantity and rate of doxycycline diffusing through the micropores directly correlated with increasing microneedle lengths (250, 500 and 750 μm). Treatment of Strat-M TM with microneedle rollers resulted in a reduction in fibroblast-mediated collagen gel contraction and MMP activity compared with untreated Strat-M TM . Our results show that treatment of an epidermal mimetic with microneedle rollers provides sufficient permeabilization for doxycycline diffusion and inhibition of MMP activity. We conclude that microneedle rollers are a promising, clinically ready tool suitable for delivery of doxycycline intradermally to treat chronic wounds.

A method of increasing the depth of the plastically deformed layer in the roller burnishing process

NASA Astrophysics Data System (ADS)

Kowalik, Marek; Trzepiecinski, Tomasz

2018-05-01

The subject of this paper is an analysis of the determination of the depth of the plastically deformed layer in the process of roller burnishing a shaft using a newly developed method in which a braking moment is applied to the roller. It is possible to increase the depth of the plastically deformed layer by applying the braking moment to the roller during the burnishing process. The theoretical considerations presented are based on the Hertz-Bielayev and Huber-Mises theories and permit the calculation of the depth of plastic deformation of the top layer of the burnished shaft. The theoretical analysis has been verified experimentally and using numerical calculations based on the finite element method using the Msc.MARC program. Experimental tests were carried out on ring-shaped samples made of C45 carbon steel. The samples were burnished at different values of roller force and different values of braking moment. A significant increase was found in the depth of the plastically deformed surface layer of roller burnished shafts. Usage of the phenomenon of strain hardening of steel allows the technology presented here to increase the fatigue life of the shafts.

Skateboarding: more dangerous than roller skating or in-line skating.

PubMed

Osberg, J S; Schneps, S E; Di Scala, C; Li, G

1998-10-01

To describe the circumstances, severity, and outcomes of skating-related injuries among children admitted to trauma centers. A cross-sectional comparison of roller skaters (n = 154), in-line skaters (n = 190), and skateboarders (n = 254) aged 5 to 19 years who were hospitalized with injuries. Seventy-nine hospitals and pediatric trauma centers participating in the National Pediatric Trauma Registry between October 1988 and April 1997. Three quarters (75.8%) of the study sample were male, nearly half (47.8%) were injured on roads, and more than one third (37.1%) had head injuries. Among skateboarders, 50.8% had head injuries compared with 33.7% of in-line skaters and 18.8% of roller skaters (P<.001). According to the Injury Severity Score, injuries to skateboarders were 8 times more likely to be severe or critical compared with roller skaters' injuries and more than 2 times as likely to be severe or critical compared with in-line skaters' injuries. Mean hospital length of stay was 6.0 days for skateboarders, 3.4 days for in-line skaters, and 2.4 days for roller skaters (P<.001). Skateboarders were more likely to be male and to be injured on roads than were in-line skaters or roller skaters. Skateboarding-related injuries are more severe and have more serious consequences than roller skating or in-line skating injuries. Research is needed to identify ergonomic and behavioral factors responsible for higher head injury risk to skateboarders, and interventions are needed to reduce the risk.

Video analysis of falls experienced by paediatric iceskaters and roller/inline skaters

PubMed Central

Knox, C L; Comstock, R D

2006-01-01

Objectives To evaluate differences in the way iceskaters and roller/inline skaters fall. Methods Children's falls related to skating were videotaped and categorised based on type of skating activity, child's estimated age, direction of fall, whether the child attempted to break the fall, and whether the head struck the skating surface. Results In total, 216 iceskating and 201 roller/inline skating falls were captured on videotape. In both iceskating and roller/inline skating, the majority of falls were forward in direction. The skaters attempted to break the falls with their arms or hands in over 90% of falls in both iceskating (93.1%) and roller/inline skating (94.5%). A greater proportion of falls in iceskating resulted in the head striking the skating surface (13.0%) than did those in roller/inline skating (3.0%) (odds ratio = 4.8; 95% confidence interval 1.9 to 13.3; p<0.001). Conclusions This study found that paediatric iceskaters and roller/inline skaters fall similarly and that both types of skaters try to break their falls with their arms or hands; however, because iceskating takes place on a low friction surface, attempts to break falls with the arms or hands are often unsuccessful, leading to head and face injuries. The development of a new type of protective gear, a wrist guard with a non‐slip palm, should stop iceskaters from striking the head, protect against upper extremity fractures, and unlike a bulky helmet, should not discourage children from skating. PMID:16505087

The selection of flying roller as an effort to increase the power of scooter-matic as the main power of centrifugal pump for fire fighter motor cycle

NASA Astrophysics Data System (ADS)

Hadi Sutrisno, Himawan

2018-03-01

In densely populated settlements, fires often occur and cause losses. In some instances, the process of the occurrence of fires takes place so quickly that to reduce and avoid the occurrence of a fire disaster effort is required in accordance with the existing environmental condition. Fire fighter motorcycle by using motorcycle scooter-matic is considered suitable as one alternative to combating fire hazard in densely populated residential settlements. The use of motorcycle engines as the driving force of the pump often leads to unstable and not optimum power. Thus, the water spray on the centrifugal pump also becomes not maximum. To increase the engine power at scooter-matic engine idle rotation (700-2000 rpm), then the flying roller replacement with certain mass weight becomes an option. By selecting a 10 to 14 gram flying roller mass, the power analysis using a dynotest engine produces several variations. Of the calculation, the mass of a 14 gram flying roller provides a significant increase in motor power on the upper rotation. Meanwhile, on the lower power rotation using a flying roller with a mass of 10 grams provides an increase in power compared to a standard flying roller on a scooter matic motor engine. As a reference to the use of scooter-matic motor power as the pump power, the result of use of the flying roller with a mass of 10 grams becomes the best option.

Remote Sensing Characteristics of Wave Breaking Rollers

NASA Astrophysics Data System (ADS)

Haller, M. C.; Catalan, P.

2006-12-01

The wave roller has a primary influence on the balances of mass and momentum in the surf zone (e.g. Svendsen, 1984; Dally and Brown, 1995; Ruessink et al., 2001). In addition, the roller area and its angle of inclination on the wave front are important quantities governing the dissipation rates in breaking waves (e.g Madsen et al., 1997). Yet, there have been very few measurements published of individual breaking wave roller geometries in shallow water. A number of investigators have focused on observations of the initial jet-like motion at the onset of breaking before the establishment of the wave roller (e.g. Basco, 1985; Jansen, 1986), while Govender et al. (2002) provide observations of wave roller vertical cross-sections and angles of inclination for a pair of laboratory wave conditions. Nonetheless, presently very little is known about the growth, evolution, and decay of this aerated region of white water as it propagates through the surf zone; mostly due to the inherent difficulties in making the relevant observations. The present work is focused on analyzing observations of the time and space scales of individual shallow water breaking wave rollers as derived from remote sensing systems. Using a high-resolution video system in a large-scale laboratory facility, we have obtained detailed measurements of the growth and evolution of the wave breaking roller. In addition, by synchronizing the remote video with in-situ wave gages, we are able to directly relate the video intensity signal to the underlying wave shape. Results indicate that the horizontal length scale of breaking wave rollers differs significantly from the previous observations of Duncan (1981), which has been a traditional basis for roller model parameterizations. The overall approach to the video analysis is new in the sense that we concentrate on individual breaking waves, as opposed to the more commonly used time-exposure technique. In addition, a new parameter of interest, denoted Imax, is introduced based on the envelope of the intensity signal. The parameter is shown to be much less sensitive to trailing wave breaking foam, which typically corrupts time-exposure data. In the present work this parameter is shown to provide high-resolution information regarding the onset of wave breaking and the spatial evolution of the wave roller. Ongoing work will attempt to relate the shoreward transformation of the intensity maximum and the geometric characteristics of the wave roller to the spatial distribution of wave breaking dissipation. Finally, we will compare wave breaking characteristics as imaged by two separate remote sensors. Synoptic images from both video and microwave radar remote sensors were obtained in September of 2005 at Duck, NC. This combination of the two observing systems will allow direct quantitative comparisons between the two imaging mechanisms and lead to a better understanding of the strengths and weaknesses of both for nearshore research and observational remote sensing.

26. Detail view of drum girder with rollers below, resting ...

Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

26. Detail view of drum girder with rollers below, resting on fixed turntable upon masonry center pier. Swing drive shaft (vertical) is turned by level gear of horizontal shaft (protruding through machine room wall), which turns pinion gear toothed to fixed turntable rack below rollers. (Nov. 25, 1988) - University Heights Bridge, Spanning Harlem River at 207th Street & West Harlem Road, New York County, NY

METHOD OF APPLYING METALLIC COATINGS

DOEpatents

Robinson, J.W.; Eubank, L.D.

1961-08-01

A method for applying a protective coating to a uranium rod is described. The steps include preheating the unanium rod to the coating temperature, placement of the rod between two rotating rollers, pouring a coating metal such as aluminum-silicon in molten form between one of the rotating rollers and the uranium rod, and rotating the rollers continually until the coating is built up to the desired thickness. (AEC)

A numerical model of a HIL scaled roller rig for simulation of wheel-rail degraded adhesion condition

NASA Astrophysics Data System (ADS)

Conti, Roberto; Meli, Enrico; Pugi, Luca; Malvezzi, Monica; Bartolini, Fabio; Allotta, Benedetto; Rindi, Andrea; Toni, Paolo

2012-05-01

Scaled roller rigs used for railway applications play a fundamental role in the development of new technologies and new devices, combining the hardware in the loop (HIL) benefits with the reduction of the economic investments. The main problem of the scaled roller rig with respect to the full scale ones is the improved complexity due to the scaling factors. For this reason, before building the test rig, the development of a software model of the HIL system can be useful to analyse the system behaviour in different operative conditions. One has to consider the multi-body behaviour of the scaled roller rig, the controller and the model of the virtual vehicle, whose dynamics has to be reproduced on the rig. The main purpose of this work is the development of a complete model that satisfies the previous requirements and in particular the performance analysis of the controller and of the dynamical behaviour of the scaled roller rig when some disturbances are simulated with low adhesion conditions. Since the scaled roller rig will be used to simulate degraded adhesion conditions, accurate and realistic wheel-roller contact model also has to be included in the model. The contact model consists of two parts: the contact point detection and the adhesion model. The first part is based on a numerical method described in some previous studies for the wheel-rail case and modified to simulate the three-dimensional contact between revolute surfaces (wheel-roller). The second part consists in the evaluation of the contact forces by means of the Hertz theory for the normal problem and the Kalker theory for the tangential problem. Some numerical tests were performed, in particular low adhesion conditions were simulated, and bogie hunting and dynamical imbalance of the wheelsets were introduced. The tests were devoted to verify the robustness of control system with respect to some of the more frequent disturbances that may influence the roller rig dynamics. In particular we verified that the wheelset imbalance could significantly influence system performance, and to reduce the effect of this disturbance a multistate filter was designed.

Research on friction torque analysis of planetary roller screw mechanism considering load distribution

NASA Astrophysics Data System (ADS)

Gan, Fajin; Mao, Pengcheng; Zheng, Shicheng; Li, Guangliang; Xin, Shupeng

2018-04-01

Based on the Hertzian contact theory, frictional moment of planetary roller screw mechanism (RSM) caused by elastic hysteresis, roller's spinning sliding, and differential sliding was analyzed, which were considering load distribution of rollers threads. The relationship between friction torque of screw pairs and its input axial load were obtained. Finally, the frictional moment of the screw pairs under the situation overstress will created at some localized contact surfaces were discussed. Results shows that the frictional moment caused by elastic hysteresis gives the greatest rise to the total frictional moment and that due to differential sliding can be ignored. The stress uniformity has great influence on the frictional moment.

Product Development and Cost Analysis of Fabricating the Prototype of Roller Clamp in Intravenous (I.V) Tubing Medical Devices using Fused Deposition Modeling (FDM) Technology

NASA Astrophysics Data System (ADS)

Way, Yusoff

2018-01-01

The main aim of this research is to develop a new prototype and to conduct cost analysis of the existing roller clamp which is one of parts attached to Intravenous (I.V) Tubing used in Intravenous therapy medical device. Before proceed with the process to manufacture the final product using Fused Deposition Modeling (FDM) Technology, the data collected from survey were analyzed using Product Design Specifications approach. Selected concept has been proven to have better quality, functions and criteria compared to the existing roller clamp and the cost analysis of fabricating the roller clamp prototype was calculated.

Roller-transducer scanning of wooden pallet parts for defect detection

Treesearch

Mohammed F. Kabir; Daniel L. Schmoldt; Mark E. Schafer

2001-01-01

Ultrasonic scanning experiments were conducted on two species of pallet deckboards using rolling transducers in a pitch-catch arrangement. Sound and unsound knots, cross grain, bark pockets, holes, splits, decay, and wane were characterized using several ultrasound parameters. Almost all parameters displayed sensitivity to defects distinctly from clear wood regions—...

Mechanical Paradox: The Uphill Roller

ERIC Educational Resources Information Center

Cortes, Emilio; Cortes-Poza, D.

2011-01-01

We analyse in detail the dynamics of a mechanical system which is a rigid body with the geometry of a double cone. This double cone is apparently able to spontaneously roll uphill along inclined rails. The experiment has been known for some centuries, and because of its peculiar behaviour, it has been named "mechanical paradox". Although this…

What Can Be Learned from the Roller Coaster Journeys of Young People Making Ultimately Successful Transitions beyond School?

ERIC Educational Resources Information Center

Bryce, Jennifer; Anderson, Michelle

2008-01-01

This project investigated the interrelationships between family expectations and young people's post-school plans. All of the participants were from financially disadvantaged families. The research used interviews to understand these young people's perspectives of their transition experiences: the ways in which young people's school experiences…

High speed cylindrical roller bearing analysis. SKF computer program CYBEAN. Volume 2: User's manual

NASA Technical Reports Server (NTRS)

Dyba, G. J.; Kleckner, R. J.

1981-01-01

CYBEAN (CYlindrical BEaring ANalysis) was created to detail radially loaded, aligned and misaligned cylindrical roller bearing performance under a variety of operating conditions. Emphasis was placed on detailing the effects of high speed, preload and system thermal coupling. Roller tilt, skew, radial, circumferential and axial displacement as well as flange contact were considered. Variable housing and flexible out-of-round outer ring geometries, and both steady state and time transient temperature calculations were enabled. The complete range of elastohydrodynamic contact considerations, employing full and partial film conditions were treated in the computation of raceway and flange contacts. The practical and correct implementation of CYBEAN is discussed. The capability to execute the program at four different levels of complexity was included. In addition, the program was updated to properly direct roller-to-raceway contact load vectors automatically in those cases where roller or ring profiles have small radii of curvature. Input and output architectures containing guidelines for use and two sample executions are detailed.

Investigation of Tapered Roller Bearing Damage Detection Using Oil Debris Analysis

NASA Technical Reports Server (NTRS)

Dempsey, Paula J.; Krieder, Gary; Fichter, Thomas

2006-01-01

A diagnostic tool was developed for detecting fatigue damage to tapered roller bearings. Tapered roller bearings are used in helicopter transmissions and have potential for use in high bypass advanced gas turbine aircraft engines. This diagnostic tool was developed and evaluated experimentally by collecting oil debris data from failure progression tests performed by The Timken Company in their Tapered Roller Bearing Health Monitoring Test Rig. Failure progression tests were performed under simulated engine load conditions. Tests were performed on one healthy bearing and three predamaged bearings. During each test, data from an on-line, in-line, inductance type oil debris sensor was monitored and recorded for the occurrence of debris generated during failure of the bearing. The bearing was removed periodically for inspection throughout the failure progression tests. Results indicate the accumulated oil debris mass is a good predictor of damage on tapered roller bearings. The use of a fuzzy logic model to enable an easily interpreted diagnostic metric was proposed and demonstrated.

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

Treesearch

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...

Numerical Simulation of Roller Levelling using SIMULIA Abaqus

NASA Astrophysics Data System (ADS)

Trusov, K. A.; Mishnev, P. A.; Kopaev, O. V.; Nushtaev, D. V.

2017-12-01

The finite element (FE) 2D-model of roller levelling process is developed in the SIMILIA Abaqus. The objective of this paper is development FE-model and investigation of adjustable parameters of roller leveller together with elastic-plastic material behaviour. Properties of the material were determined experimentally. After levelling, the strip had a residual stress distribution. The longbow after cutting is predicted too. Recommendation for practical use were proposed.

Interrelations of green oak leaf roller population and common oak: results of 30-year monitoring and mathematical modeling

Treesearch

V. V. Rubtsov; I. A. Utkina

2003-01-01

Long-term monitoring followed by mathematical modeling was used to describe the population dynamics of the green oak leaf roller Tortrix viridana L. over a period of 30 years and to study reactions of oak stands to different levels of defoliation. The mathematical model allows us to forecast the population dynamics of the green oak leaf roller and...

Roller compaction of different pseudopolymorphic forms of theophylline: Effect on compressibility and tablet properties.

PubMed

Hadzović, Ervina; Betz, Gabriele; Hadzidedić, Seherzada; El-Arini, Silvia Kocova; Leuenberger, Hans

2010-08-30

The effect of roller compaction on disintegration time, dissolution rate and compressibility of tablets prepared from theophylline anhydrate powder, theophylline anhydrate fine powder and theophylline monohydrate was studied. In addition, the influence of adding microcrystalline cellulose, a commonly used excipient, in mixtures with these materials was investigated. Theophylline anhydrate powder was used as a model drug to investigate the influence of different compaction pressures on the tablet properties. Tablets with same porosity were prepared by direct compaction and by roller compaction/re-compaction. Compressibility was characterized by Heckel and modified Heckel equations. Due to the property of polymorphic materials to change their form during milling and compression, X-ray diffraction analysis of theophylline anhydrate powder, theophylline anhydrate fine powder and theophylline monohydrate powders and granules was carried out. After roller compaction the disintegration time and the dissolution rate of the tablets were significantly improved. Compressibility of theophylline anhydrate powder and theophylline anhydrate fine powder was decreased, while theophylline monohydrate showed higher compressibility after roller compaction. Microcrystalline cellulose affected compressibility of theophylline anhydrate powder, theophylline anhydrate fine powder and theophylline monohydrate whereby the binary mixtures showed higher compressibility than the individual materials. X-ray diffraction analyses confirmed that there were no polymorphic/pseudopolymorphic changes after roller compaction. Copyright 2010 Elsevier B.V. All rights reserved.

Differential compaction behaviour of roller compacted granules of clopidogrel bisulphate polymorphs.

PubMed

Khomane, Kailas S; Bansal, Arvind K

2014-09-10

In the present work, in-die and out-of-die compaction behaviour of dry-granulated powders of clopidogrel bisulphate (CLP) polymorphs, form I and form II, was investigated using a fully instrumented rotary tablet press. Each polymorph was compacted at three different roller pressures [70.3 (S1), 105.5 (S2) and 140.6 (S3)kgf/cm(2)], and obtained granules were characterized for their physico-mechanical properties. Compaction data were analyzed for out-of-die compressibility, tabletability and compactibility profiles, and in-die Heckel, Kawakita and Walker analysis. The roller compacted granules of both forms showed markedly different tabletting behaviour. Roller pressure exhibited a trend on compaction behaviour of form I granules, whereas, in case of form II, the effect was insignificant. Tabletability of the six granule batches follows the order; I_S1>I_S2>I_S3>II_S1≈II_S2≈II_S3. In case of form I, the reduced tabletability of the granules compacted at higher roller pressure was attributed to the decreased compressibility and plastic deformation. This was confirmed by compressibility plot and various mathematical parameters derived from Heckel (Py), Kawakita (1/b) and Walker (W) equations. The reduced tabletability of form I granules was due to 'granule hardening' during roller compaction. On the other hand, insignificant effect of roller compaction on tabletting behaviour of form II granules was attributed to brittle fragmentation. The extensive fragmentation of granules offered new 'clean' surfaces and higher contact points that negated the effect of granule hardening. Copyright © 2014 Elsevier B.V. All rights reserved.

An investigation into the impact of magnesium stearate on powder feeding during roller compaction.

PubMed

Dawes, Jason; Gamble, John F; Greenwood, Richard; Robbins, Phil; Tobyn, Mike

2012-01-01

A systematic evaluation on the effect of magnesium stearate on the transmission of a placebo formulation from the hopper to the rolls during screw fed roller compaction has been carried out. It is demonstrated that, for a system with two 'knurled' rollers, addition of 0.5% w/w magnesium stearate can lead to a significant increase in ribbon mass throughput, with a consequential increase in roll gap, compared to an unlubricated formulation (manufactured at equivalent process conditions). However, this effect is reduced if one of the rollers is smooth. Roller compaction of a lubricated formulation using two smooth rollers was found to be ineffective due to a reduction in friction at the powder/roll interface, i.e. powder was not drawn through the rollers leading to a blockage in the feeding system. An increase in ribbon mass throughput could also be achieved if the equipment surfaces were pre-lubricated. However this increase was found to be temporary suggesting that the residual magnesium stearate layer was removed from the equipment surfaces. Powder sticking to the equipment surfaces, which is common during pharmaceutical manufacturing, was prevented if magnesium stearate was present either in the blend, or at the roll surface. It is further demonstrated that the influence of the hopper stirrer, which is primarily used to prevent bridge formation in the hopper and help draw powder more evenly into the auger chamber, can lead to further mixing of the formulation, and could therefore affect a change in the lubricity of the carefully blended input material.

Linear mass actuator

NASA Technical Reports Server (NTRS)

Holloway, Sidney E., III (Inventor); Crossley, Edward A., Jr. (Inventor); Jones, Irby W. (Inventor); Miller, James B. (Inventor); Davis, C. Calvin (Inventor); Behun, Vaughn D. (Inventor); Goodrich, Lewis R., Sr. (Inventor)

1992-01-01

A linear mass actuator includes an upper housing and a lower housing connectable to each other and having a central passageway passing axially through a mass that is linearly movable in the central passageway. Rollers mounted in the upper and lower housings in frictional engagement with the mass translate the mass linearly in the central passageway and drive motors operatively coupled to the roller means, for rotating the rollers and driving the mass axially in the central passageway.

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

NASA Astrophysics Data System (ADS)

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 the road rollers, is their bearings. Depending on the load, carried by the vehicle and the rotational speed of the drive wheel, the bearings themselves can greatly affect the diameter of the rollers and the whole Mecanum wheels. The solution of this problem is presented in the paper. It is illustrated with virtual models elaborated in advanced program of the CAE class.

Pediatric fractures during skateboarding, roller skating, and scooter riding.

PubMed

Zalavras, Charalampos; Nikolopoulou, Georgia; Essin, Daniel; Manjra, Nahid; Zionts, Lewis E

2005-04-01

Skateboarding, roller skating, and scooter riding are popular recreational and sporting activities for children and adolescents but can be associated with skeletal injury. The purpose of this study is to describe the frequency and characteristics of fractures resulting from these activities. Fractures from skateboarding, roller skating, and scooter riding compose a considerable proportion of pediatric musculoskeletal injuries. Case series; Level of evidence, 4. Demographic data and injury characteristics were analyzed for all patients who presented to the pediatric fracture clinic of the level I trauma center from January 2001 to May 2002 after sustaining fractures due to skateboarding, roller skating, and scooter riding. Among a total of 2371 fractures, the authors identified 325 fractures (13.7%) that occurred during one of these activities. There were 187 patients (mean age, 13 years; 95% male) who sustained 191 skateboard-related fractures, 64 patients (mean age, 10.8 years; 54% male) who sustained 65 fractures while roller skating, and 66 patients (mean age, 9.7 years; 64% male) who sustained 69 fractures while riding a scooter. The forearm was fractured most often, composing 48.2% of skate-boarding fractures, 63.1% of roller-skating fractures, and 50.7% of fractures due to scooter riding. Of the forearm fractures, 94% were located in the distal third. In the skateboarding group, 10 of 191 (5.2%) fractures were open injuries of the forearm, compared to 6 of 2046 (0.3%) fractures caused by other mechanisms of injury (significant odds ratio, 18.8). Skateboarding, roller-skating, and scooter-riding accidents result in a large proportion of pediatric fractures. An open fracture, especially of the forearm, was more likely to be caused by skateboarding than by other mechanisms of injury. Use of wrist and forearm protective equipment should be considered in all children who ride a skateboard.

A method for testing railway wheel sets on a full-scale roller rig

NASA Astrophysics Data System (ADS)

Liu, Binbin; Bruni, Stefano

2015-09-01

Full-scale roller rigs for tests on a single axle enable the investigation of several dynamics and durability problems related with the design and operation of the railway rolling stock. In order to exploit the best potential of this test equipment, appropriate test procedures need to be defined, particularly in terms of actuators' references, to make sure that meaningful wheel -rail contact conditions can be reproduced. The aim of this paper is to propose a new methodology to define the forces to be generated by the actuators in the rig in order to best reproduce the behaviour of a wheel set and especially the wheel -rail contact forces in a running condition of interest as obtained either from multi-body system (MBS) simulation or from on-track measurements. The method is supported by the use of a mathematical model of the roller rig and uses an iterative correction scheme, comparing the time histories of the contact force components from the roller rig test as predicted by the mathematical model to a set of target contact force time histories. Two methods are introduced, the first one considering a standard arrangement of the roller rig, the second one assuming that a differential gear is introduced in the rig, allowing different rolling speeds of the two rollers. Results are presented showing that the deviation of the roller rig test results from the considered targets can be kept within low tolerances (1% approximately) as far as the vertical and lateral contact forces on both wheels are concerned. For the longitudinal forces, larger deviations are obtained except in the case where a differential gear is introduced.

Vapor Cavitation in Dynamically Loaded Journal Bearings

NASA Technical Reports Server (NTRS)

Jacobson, B. O.; Hamrock, B. J.

1983-01-01

High speed motion camera experiments were performed on dynamically loaded journal bearings. The length to diameter ratio of the bearing, the speed of the roller and the tube, the surface material of the roller, and the static and dynamic eccentricity of the bearing were varied. One hundred and thirty-four cases were filmed. The occurrence of vapor cavitation was clearly evident in the films and figures presented. Vapor cavitation was found to occur when the tensile stress applied to the oil exceeded the tensile strength of the oil or the binding of the oil to the surface. The physical situation in which vapor cavitation occurs is during the squeezing and sliding motion within a bearing. Besides being able to accurately capture the vapor cavitation on film, an analysis of the formation and collapse of the cavitation bubbles and characteristics of the bubble content are presented.

Observation and analysis of emergent coherent structures in a high-energy-density shock-driven planar mixing layer experiment

DOE PAGES

Doss, Forrest William; Flippo, Kirk Adler; Merritt, Elizabeth Catherine

2016-08-03

Coherent emergent structures have been observed in a high-energy-density supersonic mixing layer experiment. A millimeter-scale shock tube uses lasers to drive Mbar shocks into the tube volume. The shocks are driven into initially solid foam (60 mg/cm 3) hemicylinders separated by an Al or Ti metal tracer strip; the components are vaporized by the drive. Before the experiment disassembles, the shocks cross at the tube center, creating a very fast (ΔU > 200 km/s) shear-unstable zone. After several nanoseconds, an expanding mixing layer is measured, and after 10+ ns we observe the appearance of streamwise-periodic, spanwise-aligned rollers associated with themore » primary Kelvin-Helmholtz instability of mixing layers. We additionally image roller pairing and spanwise-periodic streamwise-aligned filaments associated with secondary instabilities. New closures are derived to connect length scales of these structures to estimates of fluctuating velocity data otherwise unobtainable in the high-energy-density environment. Finally, this analysis indicates shear-induced specific turbulent energies 10 3 – 10 4 times higher than the nearest conventional experiments. Because of difficulties in continuously driving systems under these conditions and the harshness of the experimental environment limiting the usable diagnostics, clear evidence of these developing structures has never before been observed in this regime.« less

Computer Analysis Of High-Speed Roller Bearings

NASA Technical Reports Server (NTRS)

Coe, H.

1988-01-01

High-speed cylindrical roller-bearing analysis program (CYBEAN) developed to compute behavior of cylindrical rolling-element bearings at high speeds and with misaligned shafts. With program, accurate assessment of geometry-induced roller preload possible for variety of out-ring and housing configurations and loading conditions. Enables detailed examination of bearing performance and permits exploration of causes and consequences of bearing skew. Provides general capability for assessment of designs of bearings supporting main shafts of engines. Written in FORTRAN IV.

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

PubMed

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.

Comparison of Performance of Experimental and Conventional Cage Designs and Materials for 75-millimeter-bore Cylindrical Roller Bearings at High Speed

NASA Technical Reports Server (NTRS)

Anderson, William J; Macks, E Fred; Nemeth, Zolton N

1954-01-01

The results of two investigations, one to determine the relative merits of four experimental and two conventional design 75-millimeter-bore (size 215) cylindrical roller bearings and one to determine the relative merits of nodular iron and bronze as cage materials for this size and type of bearing, are presented in this report. Nine test bearings were operated over a range of dn values (product of bearing bore in mm and shaft speed in r.p.m) from 0.3 x 10(6) to 2.3 x 20(6), radial loads for 7 to 1613 pounds, and oil flows from 2 to 8 pounds per minute with a single-jet circulatory oil feed. Of the six bearings used to evaluate designs, four were experimental types with outer-race-riding cages and inner-race-guided rollers, and two were conventional types, one with outer-race-guided rollers and cage and one with inner-race-guided rollers and cage. Each of these six test bearings was equipped with a different design cage made of nodular iron. The experimental combination of an outer-race-riding cage with a straight-through outer race and inner-race-guided rollers was found to give the best over-all performance based on limiting dn values and bearing temperatures.

Computer program for analysis of high speed, single row, angular contact, spherical roller bearing, SASHBEAN. Volume 2: Mathematical formulation and analysis

NASA Technical Reports Server (NTRS)

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.

Effects of Clozapine and Alprazolam on Cognitive Deficits and Anxiety-Like Behaviors in a Ketamine-Induced Rat Model of Schizophrenia

DTIC Science & Technology

2005-01-01

xii LIST OF TABLES Table 1. DSM-IV-TR Criteria for Schizophrenia (abbreviated) Table 2. Experimental Design Table 3. Experiment #1... Experimental Timeline Table 4. Experiment #2: Experimental Timeline Table 5. Experiment #1: Results of MANOVAs for Prepulse Inhibition Variables...rats. Please see Table 2 for a description of treatments and cell sizes for each experiment . Table 2. Experimental Design Ketamine (mg/kg

Development of a continuous roll-to-roll processing system for mass production of plastic optical film

NASA Astrophysics Data System (ADS)

Chang, Chih-Yuan; Tsai, Meng-Hsun

2015-12-01

This paper reports a highly effective method for the mass production of large-area plastic optical films with a microlens array pattern based on a continuous roll-to-roll film extrusion and roller embossing process. In this study, a thin steel mold with a micro-circular hole array pattern is fabricated by photolithography and a wet chemical etching process. The thin steel mold was then wrapped onto a metal cylinder to form an embossing roller mold. During the roll-to-roll process operation, a thermoplastic raw material (polycarbonate grains) was put into the barrel of the plastic extruder with a flat T-die. Then, the molten polymer film was extruded and immediately pressed against the surface of the embossing roller mold. Under the proper processing conditions, the molten polymer will just partially fill the micro-circular holes of the mold and due to surface tension form a convex lens surface. A continuous plastic optical film with a microlens array pattern was obtained. Experiments are carried out to investigate the effect of plastic microlens formation on the roll-to-roll process. Finally, the geometrical and optical properties of the fabricated plastic optical film were measured and proved satisfactory. This technique shows great potential for the mass production of large-area plastic optical films with a microlens array pattern.

Method of forming magnesium alloy sheets

DOEpatents

Mualidharan, Govindarajan; Muth, Thomas R.; Harper, David C.

2015-12-22

A machine for asymmetric rolling of a work-piece includes pair of rollers disposed in an arrangement to apply opposing, asymmetric rolling forces to roll a work-piece therebetween, wherein a surface of the work-piece is rolled faster than an opposite surface of the work-piece; and an exit constraint die rigidly disposed adjacent an exit side of the pair of rollers so that, as the work-piece exits the pair of rollers, the work-piece contacts the exit constraint die to constrain curling of the work-piece.

14. UPPER SHOES, FIXED SHOES, ROLLER SHOES, CENTER WEB, AND ...

Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

14. UPPER SHOES, FIXED SHOES, ROLLER SHOES, CENTER WEB, AND ROLLER BED PLATES. (Also includes a sheet index and a schedule of parts). American Bridge Company, Ambridge Plant No. 5, sheet no. 4, dated April 7, 1928, order no. F5073. For U.S. Steel Products Company, Pacific Coast Depot, order no. SF578. For Southern Pacific Company, order no. 8873-P-28746. various scales. - Napa River Railroad Bridge, Spanning Napa River, east of Soscol Avenue, Napa, Napa County, CA

Tension is servo controlled in film advance system

NASA Technical Reports Server (NTRS)

1965-01-01

Servocontrol device feeds film into a roller system. Two linear potentiometers connected to spring loaded tension rollers furnish servo input signal. Can be used in any continuous material transport system.

14 CFR 25.693 - Joints.

Code of Federal Regulations, 2013 CFR

2013-01-01

... system joints (in push-pull systems) that are subject to angular motion, except those in ball and roller... in cable control systems. For ball or roller bearings, the approved ratings may not be exceeded...

49 CFR 215.117 - Defective roller bearing adapter.

Code of Federal Regulations, 2012 CFR

2012-10-01

... ADMINISTRATION, DEPARTMENT OF TRANSPORTATION RAILROAD FREIGHT CAR SAFETY STANDARDS Freight Car Components... a car, if the car has a roller bearing adapter that is— (a) Cracked or broken; (b) Not in its design...

49 CFR 215.117 - Defective roller bearing adapter.

Code of Federal Regulations, 2010 CFR

2010-10-01

... ADMINISTRATION, DEPARTMENT OF TRANSPORTATION RAILROAD FREIGHT CAR SAFETY STANDARDS Freight Car Components... a car, if the car has a roller bearing adapter that is— (a) Cracked or broken; (b) Not in its design...

49 CFR 215.117 - Defective roller bearing adapter.

Code of Federal Regulations, 2014 CFR

2014-10-01

... ADMINISTRATION, DEPARTMENT OF TRANSPORTATION RAILROAD FREIGHT CAR SAFETY STANDARDS Freight Car Components... a car, if the car has a roller bearing adapter that is— (a) Cracked or broken; (b) Not in its design...

49 CFR 215.117 - Defective roller bearing adapter.

Code of Federal Regulations, 2013 CFR

2013-10-01

... ADMINISTRATION, DEPARTMENT OF TRANSPORTATION RAILROAD FREIGHT CAR SAFETY STANDARDS Freight Car Components... a car, if the car has a roller bearing adapter that is— (a) Cracked or broken; (b) Not in its design...

49 CFR 215.117 - Defective roller bearing adapter.

Code of Federal Regulations, 2011 CFR

2011-10-01

... ADMINISTRATION, DEPARTMENT OF TRANSPORTATION RAILROAD FREIGHT CAR SAFETY STANDARDS Freight Car Components... a car, if the car has a roller bearing adapter that is— (a) Cracked or broken; (b) Not in its design...

Analysis of crack propagation in roller bearings using the boundary integral equation method - A mixed-mode loading problem

NASA Technical Reports Server (NTRS)

Ghosn, L. J.

1988-01-01

Crack propagation in a rotating inner raceway of a high-speed roller bearing is analyzed using the boundary integral method. The model consists of an edge plate under plane strain condition upon which varying Hertzian stress fields are superimposed. A multidomain boundary integral equation using quadratic elements was written to determine the stress intensity factors KI and KII at the crack tip for various roller positions. The multidomain formulation allows the two faces of the crack to be modeled in two different subregions, making it possible to analyze crack closure when the roller is positioned on or close to the crack line. KI and KII stress intensity factors along any direction were computed. These calculations permit determination of crack growth direction along which the average KI times the alternating KI is maximum.

Evaluation of a high-torque backlash-free roller actuator

NASA Technical Reports Server (NTRS)

Steinetz, Bruce M.

1988-01-01

The results are presented of a test program that evaluated the stiffness, accuracy, torque ripple, frictional losses, and torque holding capability of a 16:1 ratio, 430 N-m (320 ft-lb) planetary roller drive for a potential space vehicle actuator application. The drive's planet roller supporting structure and bearings were found to be the largest contributors to overall drive compliance, accounting for more than half the total. In comparison, the traction roller contacts themselves contributed only 9 percent of the drive's compliance based on an experimentally verified stiffnesss model. Torque ripple tests showed the drive to be extremely smooth, actually providing some damping of input torsional oscillations. The drive also demonstrated the ability to hold static torque with drifts of 7 arc sec or less over a 24-hour period at 35 percent of full load.

Manually Operated Welding Wire Feeder

NASA Technical Reports Server (NTRS)

Rybicki, Daniel J. (Inventor)

2001-01-01

A manual welding wire feeder apparatus comprising a bendable elongate metal frame with a feed roller mounted at the center thereof for rotation about an axis transverse to the longitudinal axis of the frame. The frame ends are turned up as tabs and each provided with openings in alignment with each other and the mid-width center of the roller surface. The tab openings are sized to accommodate welding wire and each extends to a side edge of the tab, both opening on the same side of the frame, whereby welding wire can be side-loaded onto the frame. On the side of the frame, opposite the roller a lock ring handle is attached tangentially and is rotatable about the attachment point and an axis perpendicular to the frame. The device is grasped in the hand normally used to hold the wire. A finger is placed through the loop ring and the frame positioned across the palm and lower fingers. The thumb is positioned atop the wire so it can be moved from the back of the frame across the roller, and towards the front. In doing so, the wire is advanced at a steady rate in axial alignment with the tab openings and roller. To accommodate different wire diameters the frame is bendable about its center in the plane of the frame axis and wire so as to keep the wire in sufficient tension against the roller and to keep the wire fixed when the frame is tilted and thumb pressure released.

Habitat differences in dung beetle assemblages in an African savanna-forest ecotone: implications for secondary seed dispersal.

PubMed

Kunz, Britta K; Krell, Frank-Thorsten

2011-06-01

The probability and pattern of secondary seed dispersal by dung beetles (Scarabaeinae) depend on their community structure and composition at the site of primary deposition, which, in turn, seem to be strongly determined by vegetation. Consequently, we expected pronounced differences in secondary seed dispersal between forest and savanna in the northern Ivory Coast, West Africa. We found 99 dung beetle species at experimentally exposed dung piles of the olive baboon (Papio anubis (Lesson, 1827)), an important primary seed disperser in West Africa. Seventy-six species belonged to the roller and tunneler guilds, which are relevant for secondary seed dispersal. Most species showed a clear habitat preference. Contrary to the Neotropics, species number and abundance were much higher in the savanna than in the forest. Rollers and tunnelers each accounted for approximately 50% of the individuals in the savanna, but in the forest rollers made up only 4%. Seeds deposited into the savanna by an omnivorous primary disperser generally have a higher overall probability of being more rapidly dispersed secondarily by dung beetles than seeds in the forest. Also, rollers disperse seeds over larger distances. In contrast to other studies, small rollers were active in dispersal of large seeds, which were seemingly mistaken for dung balls. Our results suggest that rollers can remove seeds from any plant dispersed in primate dung in this ecosystem. © 2011 ISZS, Blackwell Publishing and IOZ/CAS.

Moment measurements in dynamic and quasi-static spine segment testing using eccentric compression are susceptible to artifacts based on loading configuration.

PubMed

Van Toen, Carolyn; Carter, Jarrod W; Oxland, Thomas R; Cripton, Peter A

2014-12-01

The tolerance of the spine to bending moments, used for evaluation of injury prevention devices, is often determined through eccentric axial compression experiments using segments of the cadaver spine. Preliminary experiments in our laboratory demonstrated that eccentric axial compression resulted in "unexpected" (artifact) moments. The aim of this study was to evaluate the static and dynamic effects of test configuration on bending moments during eccentric axial compression typical in cadaver spine segment testing. Specific objectives were to create dynamic equilibrium equations for the loads measured inferior to the specimen, experimentally verify these equations, and compare moment responses from various test configurations using synthetic (rubber) and human cadaver specimens. The equilibrium equations were verified by performing quasi-static (5 mm/s) and dynamic experiments (0.4 m/s) on a rubber specimen and comparing calculated shear forces and bending moments to those measured using a six-axis load cell. Moment responses were compared for hinge joint, linear slider and hinge joint, and roller joint configurations tested at quasi-static and dynamic rates. Calculated shear force and bending moment curves had similar shapes to those measured. Calculated values in the first local minima differed from those measured by 3% and 15%, respectively, in the dynamic test, and these occurred within 1.5 ms of those measured. In the rubber specimen experiments, for the hinge joint (translation constrained), quasi-static and dynamic posterior eccentric compression resulted in flexion (unexpected) moments. For the slider and hinge joints and the roller joints (translation unconstrained), extension ("expected") moments were measured quasi-statically and initial flexion (unexpected) moments were measured dynamically. In the cadaver experiments with roller joints, anterior and posterior eccentricities resulted in extension moments, which were unexpected and expected, for those configurations, respectively. The unexpected moments were due to the inertia of the superior mounting structures. This study has shown that eccentric axial compression produces unexpected moments due to translation constraints at all loading rates and due to the inertia of the superior mounting structures in dynamic experiments. It may be incorrect to assume that bending moments are equal to the product of compression force and eccentricity, particularly where the test configuration involves translational constraints and where the experiments are dynamic. In order to reduce inertial moment artifacts, the mass, and moment of inertia of any loading jig structures that rotate with the specimen should be minimized. Also, the distance between these structures and the load cell should be reduced.

Is It More Thrilling to Ride at the Front or the Back of a Roller Coaster?

ERIC Educational Resources Information Center

Alberghi, Stefano; Foschi, Alessandro; Pezzi, Giovanni; Ortolani, Fabio

2007-01-01

An activity called "Project Physics, a Classroom Without Walls" was started during the spring of 2003 at the amusement park in Mirabilandia (Italy). Many thousands of students from Italian middle and high schools are today participating in the initiative. Under the guidance of trained tutors, they perform physics experiments on some of…

Granular self-organization by autotuning of friction.

PubMed

Kumar, Deepak; Nitsure, Nitin; Bhattacharya, S; Ghosh, Shankar

2015-09-15

A monolayer of granular spheres in a cylindrical vial, driven continuously by an orbital shaker and subjected to a symmetric confining centrifugal potential, self-organizes to form a distinctively asymmetric structure which occupies only the rear half-space. It is marked by a sharp leading edge at the potential minimum and a curved rear. The area of the structure obeys a power-law scaling with the number of spheres. Imaging shows that the regulation of motion of individual spheres occurs via toggling between two types of motion, namely, rolling and sliding. A low density of weakly frictional rollers congregates near the sharp leading edge whereas a denser rear comprises highly frictional sliders. Experiments further suggest that because the rolling and sliding friction coefficients differ substantially, the spheres acquire a local time-averaged coefficient of friction within a large range of intermediate values in the system. The various sets of spatial and temporal configurations of the rollers and sliders constitute the internal states of the system. Experiments demonstrate and simulations confirm that the global features of the structure are maintained robustly by autotuning of friction through these internal states, providing a previously unidentified route to self-organization of a many-body system.

Tapered Roller Bearing Damage Detection Using Decision Fusion Analysis

NASA Technical Reports Server (NTRS)

Dempsey, Paula J.; Kreider, Gary; Fichter, Thomas

2006-01-01

A diagnostic tool was developed for detecting fatigue damage of tapered roller bearings. Tapered roller bearings are used in helicopter transmissions and have potential for use in high bypass advanced gas turbine aircraft engines. A diagnostic tool was developed and evaluated experimentally by collecting oil debris data from failure progression tests conducted using health monitoring hardware. Failure progression tests were performed with tapered roller bearings under simulated engine load conditions. Tests were performed on one healthy bearing and three pre-damaged bearings. During each test, data from an on-line, in-line, inductance type oil debris sensor and three accelerometers were monitored and recorded for the occurrence of bearing failure. The bearing was removed and inspected periodically for damage progression throughout testing. Using data fusion techniques, two different monitoring technologies, oil debris analysis and vibration, were integrated into a health monitoring system for detecting bearing surface fatigue pitting damage. The data fusion diagnostic tool was evaluated during bearing failure progression tests under simulated engine load conditions. This integrated system showed improved detection of fatigue damage and health assessment of the tapered roller bearings as compared to using individual health monitoring technologies.

Fluid management in roll-to-roll nanoimprint lithography

NASA Astrophysics Data System (ADS)

Jain, A.; Bonnecaze, R. T.

2013-06-01

The key process parameters of UV roll-to-roll nanoimprint lithography are identified from an analysis of the fluid, curing, and peeling dynamics. The process includes merging of droplets of imprint material, curing of the imprint material from a viscous liquid to elastic solid resist, and pattern replication and detachment of the resist from template. The time and distances on the web or rigid substrate over which these processes occur are determined as function of the physical properties of the uncured liquid, the cured solid, and the roller configuration. The upper convected Maxwell equation is used to model the viscoelastic liquid and to calculate the force on the substrate and the torque on the roller. The available exposure time is found to be the rate limiting parameter and it is O(√Rho /uo), where R is the radius of the roller, ho is minimum gap between the roller and web, and uo is the velocity of the web. The residual layer thickness of the resist should be larger than the gap between the roller and the substrate to ensure complete feature filling and optimal pattern replication. For lower residual layer thickness, the droplets may not merge to form a continuous film for pattern transfer.

"No. 169. Congressional party visiting the roller crest dam in ...

Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

"No. 169. Congressional party visiting the roller crest dam in 1915. Dedication." - Grand Valley Diversion Dam, Half a mile north of intersection of I-70 & Colorado State Route 65, Cameo, Mesa County, CO

Railcar Roller Bearing Failure Progression Tests

DOT National Transportation Integrated Search

1982-04-01

This report describes the laboratory endurance test of six railcar roller bearings that had previously suffered physical damage or were otherwise degraded as a result of actual railroad service. Two different onboard impending bearing failure sensors...

Field evaluation of roller integrated intelligent compaction monitoring

DOT National Transportation Integrated Search

2016-05-01

DOTD conducted a demonstration : project to evaluate intelligent compaction (IC). The : project developed specifications, which allo : wed and incorporated : the IC rollers on the : project. The specification went through th : e competitive bidding p...

100. DAM ROLLER GATES GEAR SEGMENTS & TRACK ...

Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

100. DAM - ROLLER GATES - GEAR SEGMENTS & TRACK EXTENSIONS (ML-8-47/16-FS) June 1935 - Upper Mississippi River 9-Foot Channel, Lock & Dam No. 8, On Mississippi River near Houston County, MN, Genoa, Vernon County, WI

Gearbox Reliability Collaborative Gearbox 3 Planet Bearing Calibration

DOE Office of Scientific and Technical Information (OSTI.GOV)

Keller, Jonathan

2017-03-24

The Gearbox Reliability Collaborative gearbox was redesigned to improve its load-sharing characteristics and predicted fatigue life. The most important aspect of the redesign was to replace the cylindrical roller bearings with preloaded tapered roller bearings in the planetary section. Similar to previous work, the strain gages installed on the planet tapered roller bearings were calibrated in a load frame. This report describes the calibration tests and provides the factors necessary to convert the measured units from dynamometer testing to bearing loads, suitable for comparison to engineering models.

Profiled Roller Stress/Fatigue Life Analysis Methodology and Establishment of an Appropriate Stress/Life Exponent

NASA Technical Reports Server (NTRS)

1997-01-01

The objective of this work was to determine the three dimensional volumetric stress field, surface pressure distribution and actual contact area between a 0.50" square roller with different crown profiles and a flat raceway surface using Finite Element Analysis. The 3-dimensional stress field data was used in conjunction with several bearing fatigue life theories to extract appropriate values for stress-life exponents. Also, results of the FEA runs were used to evaluate the laminated roller model presently used for stress and life prediction.

3000-HP Roller Gear Transmission Development Program. Volume 3. Roller Gear Manufacture

DTIC Science & Technology

1975-07-01

power is fed through the ramp roller clutch type free- wheel units to spur gears which mesh with the combining spur gear whose centerline is common...when the engine tends to turn faster than the main rotor shaft. It is in the free- wheel mode when the main rotor shaft tends to turn faster than the...gears are cut progrind at this time. Check face runout on each end of largo gears. Not to exceed .002" TIR 30 EBW one end 40 EBW opposite end

Do Maximal Roller Skiing Speed and Double Poling Performance Predict Youth Cross-Country Skiing Performance?

PubMed Central

Stöggl, Roland; Müller, Erich; Stöggl, Thomas

2017-01-01

The aims of the current study were to analyze whether specific roller skiing tests and cycle length are determinants of youth cross-country (XC) skiing performance, and to evaluate sex specific differences by applying non-invasive diagnostics. Forty-nine young XC skiers (33 boys; 13.8 ± 0.6 yrs and 16 girls; 13.4 ± 0.9 yrs) performed roller skiing tests consisting of both shorter (50 m) and longer durations (575 m). Test results were correlated with on snow XC skiing performance (PXC) based on 3 skating and 3 classical distance competitions (3 to 6 km). The main findings of the current study were: 1) Anthropometrics and maturity status were related to boys’, but not to girls’ PXC; 2) Significant moderate to acceptable correlations between girls’ and boys’ short duration maximal roller skiing speed (double poling, V2 skating, leg skating) and PXC were found; 3) Boys’ PXC was best predicted by double poling test performance on flat and uphill, while girls’ performance was mainly predicted by uphill double poling test performance; 4) When controlling for maturity offset, boys’ PXC was still highly associated with the roller skiing tests. The use of simple non-invasive roller skiing tests for determination of PXC represents practicable support for ski clubs, schools or skiing federations in the guidance and evaluation of young talent. Key points Double poling tests on flat and uphill terrain and short duration maximal speed tests were the highest cross-country skiing predicting factors in girls and boys. Only in the boys there was an effect of maturation on the performance outcomes, pointing out that girls seem to be almost fully matured at the age of 13 in contrast to the boys. Roller skiing tests over short distance (50-m) and longer distance 225 m and 350 m are stable and valid measures and suitable for performance prediction in youth cross-country skiers. PMID:28912656

Comparison of High-Speed Operating Characteristics of Size 215 Cylindrical-Roller Bearings as Determined in Turbojet Engine and in Laboratory Test Rig

NASA Technical Reports Server (NTRS)

Macks, E Fred; Nemeth, Zolton N

1951-01-01

A comparison of the operating characteristics of 75-millimeter-bore (size 215) cylindrical-roller one-piece inner-race-riding cage-type bearings was made using a laboratory test rig and a turbojet engine. Cooling correlation parameters were determined by means of dimensional analysis, and the generalized results for both the inner- and outer-race bearing operating temperatures are compared for the laboratory test rig and the turbojet engine. Inner- and outer-race cooling-correlation curves were obtained for the turbojet-engine turbine-roller bearing with the same inner- and outer-race correlation parameters and exponents as those determined for the laboratory test-rig bearing. The inner- and outer-race turbine roller-bearing temperatures may be predicted from a single curve, regardless of variations in speed, load, oil flow, oil inlet temperature, oil inlet viscosity, oil-jet diameter or any combination of these parameters. The turbojet-engine turbine-roller-bearing inner-race temperatures were 30 to 60 F greater than the outer-race-maximum temperatures, the exact values depending on the operating condition and oil viscosity; these results are in contrast to the laboratory test-rig results where the inner-race temperatures were less than the outer-race-maximum temperatures. The turbojet-engine turbine-roller bearing, maximum outer-race circumferential temperature variation was approximately 30 F for each of the oils used. The effect of oil viscosity on inner- and outer-race turbojet-engine turbine-roller-bearing temperatures was found to be significant. With the lower viscosity oil (6x10(exp -7) reyns (4.9 centistokes) at 100 F; viscosity index, 83), the inner-race temperature was approximately 30 to 35 F less than with the higher viscosity oil (53x10(exp -7) reyns (42.8 centistokes) at 100 F; viscosity index, 150); whereas the outer-race-maximum temperatures were 12 to 28 F lower with the lower viscosity oil over the DN range investigated.

Portable Roller Staking Tool

NASA Technical Reports Server (NTRS)

Bird, R. G.; Berson, L. A.

1983-01-01

Staking tool compact and portable. Tool combines clamping and staking operations in single unit. Tool clamps workpiece (a bearing or bushing), alines it, and stakes on of flat faces. Used for most roller staking operations which acess both faces of workpiece.

Survey of Freight Car Roller Bearing Requirements and Failure Modes

DOT National Transportation Integrated Search

1973-07-01

AAR roller bearing requirements and interchange rules are presented and reviewed; also included and reviewed are rules covering adapters and grease for freight car bearings. Bearing fatigue theory, methods of fatigue life calculations, and characteri...

98. DAM ROLLER GATE GENERAL ARRANGEMENTSECTION AND ELEVATION ...

Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

98. DAM - ROLLER GATE - GENERAL ARRANGEMENT-SECTION AND ELEVATION (ML-8-47/1-FS) June 1935 - Upper Mississippi River 9-Foot Channel, Lock & Dam No. 8, On Mississippi River near Houston County, MN, Genoa, Vernon County, WI

An analytical investigation of a conceptual design for the station transverse boom rotary joint structure

NASA Technical Reports Server (NTRS)

Lake, M. S.; Bush, H. G.

1986-01-01

A study was conducted to define an annular ring, discrete roller assembly concept for the space station transverse boom rotary joint. The concept was analyzed using closed-form and finite element techniques, to size structural members for a range of joint diameters and to determine necessary equivalent stiffnesses for the roller assemblies. Also, a mass study of the system was conducted to determine its practicality, and maximum loads in the joint were identified. To obtain the optimum balance between high stiffness and low structural mass in the design of the rotary joint, it is necessary to maximize the diameter of the annular ring within operational constraints (i.e., shuttle cargo bay size). Further, a rotary joint designed with the largest possible ring diameter will result in minimum operational loads in both the roller assemblies and the transition truss members while also allowing minimum design stiffnesses for the roller assemblies.

Performance of large-bore tapered-roller bearings under combined radial and thrust load at shaft speeds to 15,000 rpm

NASA Technical Reports Server (NTRS)

Parker, R. J.; Signer, H. R.

1977-01-01

The performance of 120.65-mm bore tapered roller bearings was investigated at shaft speeds up to 15,000 rpm. Temperature distribution and bearing heat generation were determined as a function of shaft speed, radial and thrust loads, lubricant flow rate, and lubricant inlet temperature. Lubricant was supplied by either jets or by a combination of holes through the cone directly to the cone-rib contact and jets at the roller small-end side. Cone-rib lubrication significantly improved high-speed tapered-roller bearing performance, yielding lower cone-face temperatures and lower power loss and allowing lower lubricant flow rates for a given speed condition. Bearing temperatures increased with increased shaft speed and decreased with increased lubricant flow rate. Bearing power loss increased with increased shaft speed and increased lubricant flow rate.

Motorized support jack

DOEpatents

Haney, Steven J.; Herron, Donald Joe

2003-05-13

A compact, vacuum compatible motorized jack for supporting heavy loads and adjusting their positions is provided. The motorized jack includes: (a) a housing having a base; (b) a first roller device that provides a first slidable surface and that is secured to the base; (c) a second roller device that provides a second slidable surface and that has an upper surface; (d) a wedge that is slidably positioned between the first roller device and the second roller device so that the wedge is in contact with the first slidable surface and the second slidable surface; (e) a motor; and (d) a drive mechanism that connects the motor and the wedge to cause the motor to controllably move the wedge forwards or backwards. Individual motorized jacks can support and lift of an object at an angle. Two or more motorized jacks can provide tip, tilt and vertical position adjustment capabilities.

Motorized support jack

DOEpatents

Haney, Steven J.; Herron, Donald Joe

2001-01-01

A compact, vacuum compatible motorized jack for supporting heavy loads and adjusting their positions is provided. The motorized jack includes: (a) a housing having a base; (b) a first roller device that provides a first slidable surface and that is secured to the base; (c) a second roller device that provides a second slidable surface and that has an upper surface; (d) a wedge that is slidably positioned between the first roller device and the second roller device so that the wedge is in contact with the first slidable surface and the second slidable surface; (e) a motor; and (d) a drive mechanism that connects the motor and the wedge to cause the motor to controllably move the wedge forwards or backwards. Individual motorized jacks can support and lift of an object at an angle. Two or more motorized jacks can provide tip, tilt and vertical position adjustment capabilities.

Stretch-shortening cycle in roller ski skating: effects of technique.

PubMed

Perrey, S; Millet, G Y; Candau, R; Rouillon, J D

1998-11-01

The purposes of this study were 1) to examine the occurrence of the stretch-shortening cycle (SSC) in the three principal techniques of ski skating and 2) to test the hypothesis that differences in SSC behaviour may explain the choice of a technique when the grade is altered. Ten highly skilled male cross-country skiers roller skied at 5.3+/-0.1 m x s(-1) using the V1 skate (V1), V2-alternate (V2A), and V2 skate (V2) techniques. Knee and ankle joint kinematics, EMG of the vastus lateralis (VL) and gastrocnemius lateralis (GL) muscles, and roller ski velocity were recorded during the last 40 s of each bout of roller skiing. The existence of an EMG signal during the eccentric phase prior to the thrust, as well as the lack of significant delay between the two phases, showed that SSC occurs in the three techniques of roller ski skating with the exception of 50% of the subjects at the weak side knee with V1. The VL stretching velocity over the eccentric phase was higher (p < 0.005) with V2 and V2A than V1, indicating that less elastic energy was stored in the lower limbs extensor muscles with V1. This could partly explain why this technique is not used on flat terrains during races. However, no differences of average EMG activity or IEMG existed between techniques for either GL or VL during the concentric phase, suggesting that the theoretical advantage due to the SSC behaviour is minor in roller ski skating.

Effects of oil and dispersant on formation of marine oil snow and transport of oil hydrocarbons.

PubMed

Fu, Jie; Gong, Yanyan; Zhao, Xiao; O'Reilly, S E; Zhao, Dongye

2014-12-16

This work explored the formation mechanism of marine oil snow (MOS) and the associated transport of oil hydrocarbons in the presence of a stereotype oil dispersant, Corexit EC9500A. Roller table experiments were carried out to simulate natural marine processes that lead to formation of marine snow. We found that both oil and the dispersant greatly promoted the formation of MOS, and MOS flocs as large as 1.6-2.1 mm (mean diameter) were developed within 3-6 days. Natural suspended solids and indigenous microorganisms play critical roles in the MOS formation. The addition of oil and the dispersant greatly enhanced the bacterial growth and extracellular polymeric substance (EPS) content, resulting in increased flocculation and formation of MOS. The dispersant not only enhanced dissolution of n-alkanes (C9-C40) from oil slicks into the aqueous phase, but facilitated sorption of more oil components onto MOS. The incorporation of oil droplets in MOS resulted in a two-way (rising and sinking) transport of the MOS particles. More lower-molecular-weight (LMW) n-alkanes (C9-C18) were partitioned in MOS than in the aqueous phase in the presence of the dispersant. The information can aid in our understanding of dispersant effects on MOS formation and oil transport following an oil spill event.

Use of roller-compacted concrete pavement in Stafford, Virginia.

DOT National Transportation Integrated Search

2015-05-01

Roller-compacted concrete (RCC) is a relatively stiffer hydraulic cement concrete mixture than regular concrete when : fresh. Similar to regular concrete, RCC is a mixture of aggregate, cementitious materials, and water, but it is placed using asphal...

Prevention of Roller Bearing-Initiated Burnoffs in Railroad Freight Car Journals

DOT National Transportation Integrated Search

1979-01-01

The objective of this program was to determine the technical feasibility and cost effectiveness of constructing three separate devices for the prevention of catastrophic roller bearing-initiated, railroad journal failure. 1. Construction of a low cos...

Application of Roller Compacted Concrete in Colorado's Roadways

DOT National Transportation Integrated Search

2012-10-01

Roller Compacted Concrete (RCC) is a no-slump concrete mixture that is transported, placed, and compacted with : the same construction equipment as asphalt pavement. RCCs were used to construct three sections of pavement in : Weld County Road 28 (WCR...

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

PubMed Central

Sakurai, Yoshihisa; Fujita, Zenya; Ishige, Yusuke

2016-01-01

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. PMID:27049388

Decreasing inventory of a cement factory roller mill parts using reliability centered maintenance method

NASA Astrophysics Data System (ADS)

Witantyo; Rindiyah, Anita

2018-03-01

According to data from maintenance planning and control, it was obtained that highest inventory value is non-routine components. Maintenance components are components which procured based on maintenance activities. The problem happens because there is no synchronization between maintenance activities and the components required. Reliability Centered Maintenance method is used to overcome the problem by reevaluating maintenance activities required components. The case chosen is roller mill system because it has the highest unscheduled downtime record. Components required for each maintenance activities will be determined by its failure distribution, so the number of components needed could be predicted. Moreover, those components will be reclassified from routine component to be non-routine component, so the procurement could be carried out regularly. Based on the conducted analysis, failure happens in almost every maintenance task are classified to become scheduled on condition task, scheduled discard task, schedule restoration task and no schedule maintenance. From 87 used components for maintenance activities are evaluated and there 19 components that experience reclassification from non-routine components to routine components. Then the reliability and need of those components were calculated for one-year operation period. Based on this invention, it is suggested to change all of the components in overhaul activity to increase the reliability of roller mill system. Besides, the inventory system should follow maintenance schedule and the number of required components in maintenance activity so the value of procurement will be decreased and the reliability system will increase.

Rotary roller of no. 2 seamless line in bays 19 ...

Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

Rotary roller of no. 2 seamless line in bays 19 and 20 of the main pipe mill building looking north. - U.S. Steel National Tube Works, Main Pipe Mill Building, Along Monongahela River, McKeesport, Allegheny County, PA

Rotary roller mandrel of no. 2 seamless line in bays ...

Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

Rotary roller mandrel of no. 2 seamless line in bays 19 and 20 of the main pipe mill building looking south. - U.S. Steel National Tube Works, Main Pipe Mill Building, Along Monongahela River, McKeesport, Allegheny County, PA

77 FR 50716 - Tapered Roller Bearings From China

Federal Register 2010, 2011, 2012, 2013, 2014

2012-08-22

... INTERNATIONAL TRADE COMMISSION [Investigation No. 731-TA-344 (Third Review)] Tapered Roller..., the United States International Trade Commission (Commission) determines, pursuant to section 751(c... notice in the Office of the Secretary, U.S. International Trade Commission, Washington, DC, and by...

18. VIEW OF ROLLER LEVELER USED TO STRAIGHTEN AND FLATTEN ...

Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

18. VIEW OF ROLLER LEVELER USED TO STRAIGHTEN AND FLATTEN METAL SHEETS. (7/2/86) - Rocky Flats Plant, Uranium Rolling & Forming Operations, Southeast section of plant, southeast quadrant of intersection of Central Avenue & Eighth Street, Golden, Jefferson County, CO

Acoustic detection of rail car roller bearing defects. Phase III, System evaluation test.

DOT National Transportation Integrated Search

2003-08-01

In July 1999, Transportation Technology Center, Inc. (TTCI), a subsidiary of the Association of American Railroads (AAR), conducted a system evaluation test as part of the Federal Railroad Administrations (FRA) Improved Freight Car Roller Bearing ...

Vibratory roller evaluation study : interim report No. 1.

DOT National Transportation Integrated Search

1974-08-01

The Louisiana Department of Highways has in progress a two phase program to evaluate the use of vibratory rollers in the compaction of asphaltic concrete pavements. Phase one on the first construction project is now complete with eight different vibr...

Bead Roller, at right, used for preparing flume sheeting (still ...

Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

Bead Roller, at right, used for preparing flume sheeting (still in use, 2004); on left is a pipe cutter. Facing southeast - Childs-Irving Hydroelectric Project, Childs System, Childs Powerhouse, Forest Service Road 708/502, Camp Verde, Yavapai County, AZ

Method and apparatus for setting precise nozzle/belt and nozzle/edge dam block gaps

DOEpatents

Carmichael, Robert J.; Dykes, Charles D.; Woodrow, Ronald

1989-05-16

A pair of guide pins are mounted on sideplate extensions of the caster and mating roller pairs are mounted on the nozzle assembly. The nozzle is advanced toward the caster so that the roller pairs engage the guide pins. Both guide pins are remotely adjustable in the vertical direction by hydraulic cylinders acting through eccentrics. This moves the nozzle vertically. The guide pin on the inboard side of the caster is similarly horizontally adjustable. The nozzle roller pair which engage the inboard guide pin are flanged so that the nozzle moves horizontally with the inboard guide pin.

TUBE FLANGING APPARATUS HAVING SPIRAL CAM ACTUATED FLANGING ROLLERS

DOEpatents

Bellarts, H.J.

1958-06-24

A tube flaring apparatus designed to roll flawless uniform flanges on tube ends suitable for use in a Van Stone joint is described. Tapered rollers are mounted on gear segnnents and placed in the end of the tube. The assembly is rotated axially within the tube, and periodically the gear segments are moved by a worm gear so as to force the rollers radially against the tube wall until eventually a perfect 90 d flange is formed on the tube. All flanges formed by this machine are uniform, stronger, and have fewer possibilities for leaks than conventional methods heretofore used.

Variable loading roller

DOEpatents

Williams, Daniel M.

1989-01-01

An automatic loading roller for transmitting torque in traction drive devices in manipulator arm joints includes a two-part camming device having a first cam portion rotatable in place on a shaft by an input torque and a second cam portion coaxially rotatable and translatable having a rotating drive surface thereon for engaging the driven surface of an output roller with a resultant force proportional to the torque transmitted. Complementary helical grooves on the respective cam portions interconnected through ball bearings interacting with those grooves effect the rotation and translation of the second cam portion in response to rotation of the first.

Variable loading roller

DOEpatents

Williams, D.M.

1988-01-21

An automatic loading roller for transmitting torque in traction drive devices in manipulator arm joints includes a two-part camming device having a first cam portion rotatable in place on a shaft by an input torque and a second cam portion coaxially rotatable and translatable having a rotating drive surface thereon for engaging the driven surface of an output roller with a resultant force proportional to the torque transmitted. Complementary helical grooves in the respective cam portions interconnected through ball bearings interacting with those grooves effect the rotation and translation of the second cam portion in response to rotation of the first. 14 figs.

Supervisory Control of the Right Arm of the Beam Assembly Teleoperator.

DTIC Science & Technology

1985-05-10

22332 L pQ5)1OLLA, Fg & E AND ADDRESS 12. REPORT DATE ATTN: DAPC-OPA-E 10 May 85 200 Stovall Street 13 NUMBEROF PAGES tf1 Alexandria. V4rqi nia 22332 171...MODUOE MOO FIGURE~ I. RgTArSuste -ll7- DC MOTOR END EFFECTOR FOR ROLLER SMALL POWER MODULE SOLENOID VALVE BOX MAIN POWER FIGURE A.6 Left Arm Subsystem...closed pneumatically. It is controlled by the ICS through the solenoid valve box and the RRT. At the base of the end effector is a roller. This roller

Composite prepreg application device

NASA Technical Reports Server (NTRS)

Sandusky, Donald A. (Inventor); Marchello, Joseph M. (Inventor)

1995-01-01

A heated shoe and cooled pressure roller assembly for composite prepreg application is provided. The shoe assembly includes a heated forward contact surface having a curved pressure surface. The following cooled roller provides a continuous pressure to the thermoplastic while reducing the temperature to approximately 5 C below glass transition temperature. Electric heating coils inside the forward portion of the shoe heat a thermoplastic workpiece to approximately 100 C above the glass transition. Immediately following the heated contact surface, a cooled roller cools the work. The end sharpened shape of the heated shoe trailing edge tends to prevent slag buildup and maintain a uniform, relaxed stress fabrication.

Roller skating injuries in children.

PubMed

Inkelis, S H; Stroberg, A J; Keller, E L; Christenson, P D

1988-06-01

Many children who roller skate sustain injuries. To determine the type and severity of these mishaps, the medical records of 76 children less than 16 years of age with roller skating injuries presenting to two pediatric emergency departments were reviewed. Seventy-five percent were girls, and 25% were boys. The upper extremity was the most common body part injured (74%) (P less than 0.0001). Lower extremity injuries occurred in 12%, head and face injuries in 10%, and chest injuries in 4%. The most common type of injury was a fracture (69%), with the wrist and forearm being most frequently fractured (53%). Hospitalization and long-term sequelae were infrequent. Younger children (less than or equal to 9) had an increased frequency of fracture injury (P less than 0.02). This is most likely because maturation of lower and upper extremity speed, strength, agility, coordination, balance, and reaction time and morphologically stronger bones combine to afford relative protection to the older child. Physicians and parents need to be aware of a child's skill level before the child is encouraged to roller skate. Measures which may decrease the likelihood of injury include protective gear, instruction in roller skating technique, learning to skate in an uncongested area on level, familiar terrain, and learning to fall properly.

Remote repair appliance

DOEpatents

Heumann, Frederick K.; Wilkinson, Jay C.; Wooding, David R.

1997-01-01

A remote appliance for supporting a tool for performing work at a worksite on a substantially circular bore of a workpiece and for providing video signals of the worksite to a remote monitor comprising: a baseplate having an inner face and an outer face; a plurality of rollers, wherein each roller is rotatably and adjustably attached to the inner face of the baseplate and positioned to roll against the bore of the workpiece when the baseplate is positioned against the mouth of the bore such that the appliance may be rotated about the bore in a plane substantially parallel to the baseplate; a tool holding means for supporting the tool, the tool holding means being adjustably attached to the outer face of the baseplate such that the working end of the tool is positioned on the inner face side of the baseplate; a camera for providing video signals of the worksite to the remote monitor; and a camera holding means for supporting the camera on the inner face side of the baseplate, the camera holding means being adjustably attached to the outer face of the baseplate. In a preferred embodiment, roller guards are provided to protect the rollers from debris and a bore guard is provided to protect the bore from wear by the rollers and damage from debris.

Standardization and assessment of cell culture media quantities in roller poly ethylene terephthalate bottles employed in the industrial rabies viral vaccine production.

PubMed

Jagannathan, S; Chaansha, S; Rajesh, K; Santhiya, T; Charles, C; Venkataramana, K N

2009-09-15

Vero cells are utilized for production of rabies vaccine. This study deals with the optimize quantity media require for the rabies vaccine production in the smooth roller surface. The rabies virus (Pasteur vaccine strain) is infected to monolayer of the various experimented bottles. To analyze the optimal quantity of media for the production of rabies viral harvest during the process of Vero cell derived rabies vaccine. The trials are started from 200 to 400 mL (PTARV-1, PTARV-2, PTARV-3, PTARV-4 and PTARV-5). The samples are taken in an appropriate time intervals for analysis of In Process Quality Control (IPQC) tests. The collected viral harvests are further processed to rabies vaccine in a pilot level and in addition to scale up an industrial level. Based on the evaluation the PTARV-2 (250 mL) show highly encouraging results for the Vero cell derived rabies vaccine production.

76 FR 73596 - Notice of Scope Rulings

Federal Register 2010, 2011, 2012, 2013, 2014

2011-11-29

... LLC and OTR Wheel Engineering, Inc.; its wheel hub units/assemblies with tapered roller bearings are...-601: Tapered Roller Bearings from the People's Republic of China Requestor: New Trend Engineering... Requestor: OTR Wheel Engineering, Inc. (``OTR Wheel''); whether OTR Wheel's ``Trac Master'' and ``Traction...

Acoustic detection of railcar roller bearing defects. Phase I, Laboratory test.

DOT National Transportation Integrated Search

2003-06-01

A series of tests were performed at the Bearing Test Facility at the Transportation Technology Center, Inc. (TTCI) in Pueblo, Colorado, to gather acoustic and acceleration emissions for a number of roller bearing defect types designated by the rail i...

Better Seals for Vacuum Bags

NASA Technical Reports Server (NTRS)

Penn, B.; Clemons, J. M.

1983-01-01

Roller tool spreads even layer of adhesive. Tool easily constructed from metal, plastic, or wood. Sewing-thread spool serves as roller, nail as axle, and jigsawed block of wood as handle. Tool rolled and pressed against plastic film to assure even layer of adhesive around periphery.

Roller compaction of moist pharmaceutical powders.

PubMed

Wu, C-Y; Hung, W-L; Miguélez-Morán, A M; Gururajan, B; Seville, J P K

2010-05-31

The compression behaviour of powders during roller compaction is dominated by a number of factors, such as process conditions (roll speed, roll gap, feeding mechanisms and feeding speed) and powder properties (particle size, shape, moisture content). The moisture content affects the powder properties, such as the flowability and cohesion, but it is not clear how the moisture content will influence the powder compression behaviour during roller compaction. In this study, the effect of moisture contents on roller compaction behaviour of microcrystalline cellulose (MCC, Avicel PH102) was investigated experimentally. MCC samples of different moisture contents were prepared by mixing as-received MCC powder with different amount of water that was sprayed onto the powder bed being agitated in a rotary mixer. The flowability of these samples were evaluated in terms of the poured angle of repose and flow functions. The moist powders were then compacted using the instrumented roller compactor developed at the University of Birmingham. The flow and compression behaviour during roller compaction and the properties of produced ribbons were examined. It has been found that, as the moisture content increases, the flowability of moist MCC powders decreases and the powder becomes more cohesive. As a consequence of non-uniform flow of powder into the compaction zone induced by the friction between powder and side cheek plates, all produced ribbons have a higher density in the middle and lower densities at the edges. For the ribbons made of powders with high moisture contents, different hydration states across the ribbon width were also identified from SEM images. Moreover, it was interesting to find that these ribbons were split into two halves. This is attributed to the reduction in the mechanical strength of moist powder compacts with high moisture contents produced at high compression pressures. Copyright (c) 2010 Elsevier B.V. All rights reserved.

Nest ecology of blood parasites in the European roller and its ectoparasitic carnid fly.

PubMed

Václav, Radovan; Betáková, Tatiana; Švančarová, Petra; Pérez-Serrano, Jorge; Criado-Fornelio, Ángel; Škorvanová, Lucia; Valera, Francisco

2016-06-01

Haemosporidian parasites are considered the most important vector-borne parasites. However, vector identity and ecology is unknown for most such host-vector-parasite systems. In this study, we employ microscopic and molecular analyses to examine haemosporidian prevalence in a migratory, cavity-nesting bird, European roller Coracias garrulus, and its nidicolous blood-feeding ectoparasite Carnus hemapterus. This system is unique in that the ectoparasite is confined to a near-closed environment, in contrast to the free-wandering system of haematophagous dipterans such as mosquitoes. Blood film analysis confirms previous works in that Haemoproteus parasites are widely prevalent in adult rollers and belong to a single species, Haemoproteus coraciae. Leucocytozoon sp. and Trypanosoma sp. also are detected in adult rollers at low intensities with this technique. By means of molecular analysis, we report for the first time Plasmodium sp. presence in C. garrulus. Based on PCR results, Plasmodium parasites are relatively less prevalent than Haemoproteus parasites (20% vs. 31%) in rollers. In contrast, haemosporidian prevalences show the opposite trend for Carnus flies: Plasmodium sp. occurrence (62%) clearly predominates over that of Haemoproteus sp. (5%). A comparison between roller and Carnus samples reveals a significantly higher prevalence of Plasmodium sp. in Carnus samples. Insect survey and phylogenetic analysis suggest Culicoides flies as Haemoproteus sp. vectors, which appear to readily transmit the parasite in southern Spain. This study does not find support for Carnus flies to serve as biological or mechanical vectors of haemosporidians. In spite of this, nidicolous blood-feeding ectoparasites, such as carnid flies, appear as a suitable model for studies on the occurrence and temporal dynamics of avian haemosporidians such as Plasmodium sp. present at low intensities. Copyright © 2016 Elsevier Inc. All rights reserved.

Roller Coaster Science.

ERIC Educational Resources Information Center

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…

Roller Skating; Physical Education: 9.8414.

ERIC Educational Resources Information Center

Amacker, Kathy; Mikell, Lenora

GRADES OR AGES: Grades 7-12. SUBJECT MATTER: Methods and procedures of roller skating. ORGANIZATION AND PHYSICAL APPEARANCE: The contents are divided into six areas, which are Course Guidelines, Course Description and Accreditation Standard Broad Goal, Course of Study Behavioral Objectives, Course Content, Learning Activities and Teaching…

Compaction of asphaltic concrete pavement with high intensity pneumatic roller : part I.

DOT National Transportation Integrated Search

1963-07-01

The purpose of this investigation was to: : 1) Determine the magnitude of the compactive effort and the umber of passes required in the field to obtain optimum density using a high intensity pneumatic roller. : 2) Effect a correlation between the fie...

Productivity of a large-wheeled skidder and roller chopper for preparing sites.

Treesearch

Edwin S. Miyata; Helmuth M. Steinhilb; Glenn D. Mroz; Lynne A. Coyer

1983-01-01

Discusses the results of a field test of a Pettibone Master 1500 skidder and Flecor Corporation SS812 roller chopper for site preparation work in Wisconsin. Includes cost, productivity, and effectiveness of site preparation on 23.4 acres (9.47 ha).

Roller Locking Brake

NASA Technical Reports Server (NTRS)

Vranish, John M.

1993-01-01

Roller locking brake is normally braking rotary mechanism allowing free rotation when electromagnet in mechanism energized. Well suited to robots and other machinery which automatic braking upon removal of electrical power required. More compact and reliable. Requires little electrical power to maintain free rotation and exhibits minimal buildup of heat.

Load beam unit replaceable inserts for dry coal extrusion pumps

DOEpatents

Saunders, Timothy; Brady, John D.

2012-11-13

A track assembly for a particulate material extrusion pump according to an exemplary aspect of the present disclosure includes a link assembly with a roller bearing. An insert mounted to a load beam located such that the roller bearing contacts the insert.

Investigation of improved compaction by rubber-tire rollers : final report.

DOT National Transportation Integrated Search

1987-01-01

The study consisted of a review of the literature and field testing on five projects. The field testing on each project consisted of rolling a conventional section using the contractor's steel-wheel rollers and rolling a test section using a rubber-t...

Rolling Bearing Life Prediction-Past, Present, and Future

NASA Technical Reports Server (NTRS)

Zaretsky, E V; Poplawski, J. V.; Miller, C. R.

2000-01-01

Comparisons were made between the life prediction formulas of Lundberg and Palmgren, Ioannides and Harris, and Zaretsky and full-scale ball and roller bearing life data. The effect of Weibull slope on bearing life prediction was determined. Life factors are proposed to adjust the respective life formulas to the normalized statistical life distribution of each bearing type. The Lundberg-Palmgren method resulted in the most conservative life predictions compared to Ioannides and Harris, and Zaretsky methods which produced statistically similar results. Roller profile can have significant effects on bearing life prediction results. Roller edge loading can reduce life by as much as 98 percent. The resultant predicted life not only depends on the life equation used but on the Weibull slope assumed, the least variation occurring with the Zaretsky equation. The load-life exponent p of 10/3 used in the American National Standards Institute (ANSI)/American Bearing Manufacturers Association (ABMA)/International Organization for Standardization (ISO) standards is inconsistent with the majority roller bearings designed and used today.

Corning HYPERFlask® for viral amplification and production of diagnostic reagents.

PubMed

Kearney, Brian J; Voorhees, Matthew A; Williams, Priscilla L; Olschner, Scott P; Rossi, Cynthia A; Schoepp, Randal J

2017-04-01

Viral preparations are essential components in diagnostic research and development. The production of large quantities of virus traditionally is done by infecting numerous tissue culture flasks or roller bottles, which require large incubators and/or roller bottle racks. The Corning HYPERFlask ® is a multilayer flask that uses a gas permeable film to provide gas exchange between the cells and culture medium and the atmospheric environment. This study evaluated the suitability of the HYPERFlask for production of Lassa, Ebola, Bundibugyo, Reston, and Marburg viruses and compared it to more traditional methods using tissue culture flasks and roller bottles. The HYPERFlask produced cultures were equivalent in virus titer and indistinguishable in immunodiagnostic assays. The use of the Corning HYPERFlask for viral production is a viable alternative to traditional tissue culture flasks and roller bottles. HYPERFlasks allow for large volumes of virus to be produced in a small space without specialized equipment. Copyright © 2016. Published by Elsevier B.V.

Cutting roller

DOE Office of Scientific and Technical Information (OSTI.GOV)

Best, G.; Weikert, N.B.

1984-05-29

A cutting roller for a mining machine, having a substantially conical closure member arranged to face the workings and a tubular body member which has a larger diameter at the end nearer the face working face than at the discharge end. The tubular member carries at least one cutting blade, and the closure member mounts at least one cutting blade; each blade is provided at its edge region with a plurality of bit holders for the attachment of cutter bits. The outer surface of the body member merges into the substantially conical closure member in a smooth, even curve, somore » that the outside diameter of the body member in the region of the working face is substantially greater than the diameter in the region of the discharge end of the cutting roller. The roller is provided with liquid distribution channels on each cutting blade, which channels are connected to a single liquid distribution ring channel in the region of the substantially conical closure member.« less

Regenerative braking device

DOEpatents

Hoppie, Lyle O.

1982-01-12

Disclosed are several embodiments of a regenerative braking device for an automotive vehicle. The device includes a plurality of rubber rollers (24, 26) mounted for rotation between an input shaft (14) connectable to the vehicle drivetrain and an output shaft (16) which is drivingly connected to the input shaft by a variable ratio transmission (20). When the transmission ratio is such that the input shaft rotates faster than the output shaft, the rubber rollers are torsionally stressed to accumulate energy, thereby slowing the vehicle. When the transmission ratio is such that the output shaft rotates faster than the input shaft, the rubber rollers are torsionally relaxed to deliver accumulated energy, thereby accelerating or driving the vehicle.

Bearing construction for refrigeration compresssor

DOEpatents

Middleton, Marc G.; Nelson, Richard T.

1988-01-01

A hermetic refrigeration compressor has a cylinder block and a crankshaft rotatable about a vertical axis to reciprocate a piston in a cylinder on the cylinder block. A separate bearing housing is secured to the central portion of the cylinder block and extends vertically along the crankshaft, where it carries a pair of roller bearings to journal the crankshaft. The crankshaft has a radially extending flange which is journaled by a thrust-type roller bearing above the bearing housing to absorb the vertical forces on the crankshaft so that all three of the roller bearings are between the crankshaft and the bearing housing to maintain and control the close tolerances required by such bearings.

Composite prepreg application device

NASA Technical Reports Server (NTRS)

Sandusky, Donald A. (Inventor); Marchello, Joseph M. (Inventor)

1996-01-01

A heated shoe and cooled pressure roller assembly for composite prepreg application is provided. The shoe assembly includes a heated forward contact surface having a curved pressure surface. The following cooled roller provides a continuous pressure to the thermoplastic while reducing the temperature to approximately 5.degree. C. below glass transition temperature. Electric heating coils inside the forward portion of the shoe heat a thermoplastic workpiece to approximately 100.degree. C. above the glass transition. Immediately following the heated contact surface, a cooled roller cools the work. The end sharpened shape of the heated shoe trailing edge tends to prevent slag buildup and maintain a uniform, relaxed stress fabrication.

77 FR 2271 - Tapered Roller Bearings and Parts Thereof, Finished and Unfinished, From the People's Republic of...

Federal Register 2010, 2011, 2012, 2013, 2014

2012-01-17

... DEPARTMENT OF COMMERCE International Trade Administration [A-570-601] Tapered Roller Bearings and...: Import Administration, International Trade Administration, Department of Commerce. SUMMARY: On July 13, 2011, the Department of Commerce (``Department'') published the preliminary results and intent to...

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

USDA-ARS?s Scientific Manuscript database

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...

Modeling of contact theories for the manipulation of biological micro/nanoparticles in the form of circular crowned rollers based on the atomic force microscope

DOE Office of Scientific and Technical Information (OSTI.GOV)

Korayem, M. H.; Khaksar, H.; Taheri, M.

2013-11-14

This article has dealt with the development and modeling of various contact theories for biological nanoparticles shaped as cylinders and circular crowned rollers for application in the manipulation of different biological micro/nanoparticles based on Atomic Force Microscope. First, the effective contact forces were simulated, and their impact on contact mechanics simulation was investigated. In the next step, the Hertz contact model was simulated and compared for gold and DNA nanoparticles with the three types of spherical, cylindrical, and circular crowned roller type contact geometries. Then by reducing the length of the cylindrical section in the circular crowned roller geometry, themore » geometry of the body was made to approach that of a sphere, and the results were compared for DNA nanoparticles. To anticipatory validate the developed theories, the results of the cylindrical and the circular crowned roller contacts were compared with the results of the existing spherical contact simulations. Following the development of these contact models for the manipulation of various biological micro/nanoparticles, the cylindrical and the circular crowned roller type contact theories were modeled based on the theories of Lundberg, Dowson, Nikpur, Heoprich, and Hertz for the manipulation of biological micro/nanoparticles. Then, for a more accurate validation, the results obtained from the simulations were compared with those obtained by the finite element method and with the experimental results available in previous articles. The previous research works on the simulation of nanomanipulation have mainly investigated the contact theories used in the manipulation of spherical micro/nanoparticles. However since in real biomanipulation situations, biological micro/nanoparticles of more complex shapes need to be displaced in biological environments, this article therefore has modeled and compared, for the first time, different contact theories for use in the biomanipulation of cylindrical and circular crowned roller shaped micro/nanoparticles. The results of models indicate that the contact model of Hertz achieves the largest amount of deformation for the DNA nanoparticle in cylindrical form and the contact model of Heoprich achieves the largest deformation for the circular crowned roller shaped DNA. Of course, this finding is not always true for the other nanoparticles; and considering the mechanical and environmental characteristics, different results can be obtained. Also, by comparing the deformations of different types of nanoparticles, it was determined that the platelet type nanoparticles display the highest degree of deformation in all the considered models, due to their particular mechanical characteristics.« less

Innovative Design to Prevent Reversal of Roller Blood Pump Rotation in the Event of Electromechanical Failure: An Easy Solution to a Devastating Problem

PubMed Central

Skoletsky, Jennifer S.; White, Brian T.; Austin, Jon W.

2007-01-01

Abstract: 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 heartlung 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 180° 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. PMID:17672191

Laterally bendable belt conveyor

DOEpatents

Peterson, William J.

1985-01-01

An endless, laterally flexible and bendable belt conveyor particularly adapted for coal mining applications in facilitating the transport of the extracted coal up- or downslope and around corners in a continuous manner is disclosed. The conveying means includes a flat rubber belt reinforced along the middle portion thereof along which the major portion of the belt tension is directed so as to cause rotation of the tubular shaped belt when trammed around lateral turns thus preventing excessive belt bulging distortion between adjacent belt supports which would inhibit belt transport. Pretension induced into the fabric reinforced flat rubber belt by conventional belt take-up means supports the load conveyed when the belt conveyor is making lateral turns. The carrying and return portions of the belt are supported and formed into a tubular shape by a plurality of shapers positioned along its length. Each shaper is supported from above by a monorail and includes clusters of idler rollers which support the belt. Additional cluster rollers in each shaper permit the belt supporting roller clusters to rotate in response to the belt's operating tension imposed upon the cluster rollers by induced lateral belt friction forces. The freely rotating roller clusters thus permit the belt to twist on lateral curves without damage to itself while precluding escape of the conveyed material by effectively enclosing it in the tube-shaped, inner belt transport length.

Remote repair appliance

DOEpatents

Heumann, F.K.; Wilkinson, J.C.; Wooding, D.R.

1997-12-16

A remote appliance for supporting a tool for performing work at a work site on a substantially circular bore of a work piece and for providing video signals of the work site to a remote monitor comprises: a base plate having an inner face and an outer face; a plurality of rollers, wherein each roller is rotatably and adjustably attached to the inner face of the base plate and positioned to roll against the bore of the work piece when the base plate is positioned against the mouth of the bore such that the appliance may be rotated about the bore in a plane substantially parallel to the base plate; a tool holding means for supporting the tool, the tool holding means being adjustably attached to the outer face of the base plate such that the working end of the tool is positioned on the inner face side of the base plate; a camera for providing video signals of the work site to the remote monitor; and a camera holding means for supporting the camera on the inner face side of the base plate, the camera holding means being adjustably attached to the outer face of the base plate. In a preferred embodiment, roller guards are provided to protect the rollers from debris and a bore guard is provided to protect the bore from wear by the rollers and damage from debris. 5 figs.

Detection of internally infested popcorn using electrically conductive roller mills

USDA-ARS?s Scientific Manuscript database

To detect popcorn kernels infested by the internal feeding stored-product insect pest Sitophilus zeamais, maize weevil, a laboratory roller mill was modified so that the electrical conductivity of the grain is measured while the kernels are milled between the rolls. When a kernel with a S. zeamais l...

AXONOMETRIC, LAUNCH DOOR AND DOOR CYLINDER, LAUNCH PLATFORM ROLLER GUIDE, ...

Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

AXONOMETRIC, LAUNCH DOOR AND DOOR CYLINDER, LAUNCH PLATFORM ROLLER GUIDE, CRIB SUSPENSION SHOCK STRUT, LAUNCH PLATFORM - Dyess Air Force Base, Atlas F Missle Site S-8, Launch Facility, Approximately 3 miles east of Winters, 500 feet southwest of Highway 1770, center of complex, Winters, Runnels County, TX

78 FR 40692 - Tapered Roller Bearings and Parts Thereof, Finished and Unfinished, From the People's Republic of...

Federal Register 2010, 2011, 2012, 2013, 2014

2013-07-08

... DEPARTMENT OF COMMERCE International Trade Administration [A-570-601] Tapered Roller Bearings and..., International Trade Administration, Department of Commerce. SUMMARY: The Department of Commerce (Department) is... Department selected one mandatory respondent for individual examination (i.e., Changshan Peer Bearing Co. Ltd...

77 FR 24179 - Tapered Roller Bearings and Parts Thereof, Finished and Unfinished, From the People's Republic of...

Federal Register 2010, 2011, 2012, 2013, 2014

2012-04-23

... DEPARTMENT OF COMMERCE International Trade Administration [A-570-601] Tapered Roller Bearings and... Trade Administration, Department of Commerce. DATES: Effective Date: April 23, 2012. SUMMARY: On January 17, 2012, the Department of Commerce (``Department'') published the final results of the antidumping...

78 FR 38943 - Tapered Roller Bearings and Parts Thereof, Finished and Unfinished, From the People's Republic of...

Federal Register 2010, 2011, 2012, 2013, 2014

2013-06-28

... DEPARTMENT OF COMMERCE International Trade Administration [A-570-601] Tapered Roller Bearings and..., Department of Commerce. SUMMARY: The Department of Commerce (the Department) has received information..., International Trade Administration, U.S. Department of Commerce, 14th Street and Constitution Avenue NW...

Compaction of asphaltic concrete pavement with high intensity pneumatic roller : part II : densification due to traffic.

DOT National Transportation Integrated Search

1965-10-01

In the early of 1961 a research project was undertaken by the Louisiana Department of Highways in cooperation with the Bureau of Public Roads to study the effect of high intensity pneumatic rollers on the density of asphaltic concrete pavement using ...

New seed-cotton reclaimer for high speed roller gins

USDA-ARS?s Scientific Manuscript database

An experimental laboratory prototype reclaimer is being developed by the USDA-ARS in cooperation with Lummus Corporation. The objective of the project is to develop a seed-cotton reclaimer for high speed roller ginning that has a higher operational capacity and reduced seed loss in comparison to cur...

Effect on interference fits on roller bearing fatigue life

NASA Technical Reports Server (NTRS)

Coe, H. H.; Zaretsky, E. V.

1986-01-01

An analysis was performed to determine the effects of inner-ring speed and press fits on roller bearing fatigue life. The effects of the resultant hoop and radial stresses on the principal stresses were considered. The maximum shear stresses below the Hertzian contact were determined for different conditions of inner-ring speed and load, and were applied to a conventional roller bearing life analysis. The effect of mean stress was determined using Goodman diagram approach. Hoop stresses caused by press fits and centrifugal force can reduce bearing life by as much as 90 percent. Use of a Goodman diagram predicts life reductions of 20 to 30 percent. The depth of the maximum shear stress remains virtually unchanged.

Effect of interference fits on roller bearing fatigue life

NASA Technical Reports Server (NTRS)

Coe, Harold H.; Zaretsky, Erwin V.

1987-01-01

An analysis was performed to determine the effects of inner-ring speed and press fits on roller bearing fatigue life. The effects of the resultant hoop and radial stresses on the principal stresses were considered. The maximum shear stresses below the Hertzian contact were determined for different conditions of inner-ring speed and load, and were applied to a conventional roller bearing life analysis. The effect of mean stress was determined using Goodman diagram approach. Hoop stresses caused by press fits and centrifugal force can reduce bearing life by as much as 90 percent. Use of a Goodman diagram predicts life reduction of 20 to 30 percent. The depth of the maximum shear stress remains virtually unchanged.

Modeling of rolling element bearing mechanics

NASA Technical Reports Server (NTRS)

Greenhill, L. M.

1991-01-01

Roller element bearings provide the primary mechanical interface between rotating and nonrotating components in the high performance turbomachinery of the Space Shuttle Main Engine (SSME). Knowledge of bearing behavior under various loading and environmental conditions is essential to predicting and understanding the overall behavior of turbopumps, including rotordynamic stability, critical speeds and bearing life. The objective is to develop mathematical models and computer programs to describe the mechanical behavior of ball and cylinder roller bearings under the loading and environmental conditions encountered in the SSME and future high performance rocket engines. This includes characteristics such as nonlinear load/motion relationships, stiffness and damping, rolling element loads for life prediction, and roller and cage stability.

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

DOE Office of Scientific and Technical Information (OSTI.GOV)

Zheng, Yi; Zhang, Qin; Liu, Jing, E-mail: jliu@mail.ipc.ac.cn

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 themore » roller-ball pen electronics.« less

High speed cylindrical roller bearing analysis, SKF computer program CYBEAN. Volume 2: User's manual

NASA Technical Reports Server (NTRS)

Kleckner, R. J.; Pirvics, J.

1978-01-01

The CYBEAN (Cylindrical Bearing Analysis) was created to detail radially loaded, aligned and misaligned cylindrical roller bearing performance under a variety of operating conditions. Emphasis was placed on detailing the effects of high speed, preload and system thermal coupling. Roller tilt, skew, radial, circumferential and axial displacement as well as flange contact were considered. Variable housing and flexible out-of-round outer ring geometries, and both steady state and time transient temperature calculations were enabled. The complete range of elastohydrodynamic contact considerations, employing full and partial film conditions were treated in the computation of raceway and flange contacts. Input and output architectures containing guidelines for use and a sample execution are detailed.

Sidewall containment of liquid metal with horizontal alternating magnetic fields

DOEpatents

Pareg, Walter F.

1990-01-01

An apparatus for confining molten metal with a horizontal alternating magnetic field. In particular, this invention employs a magnet that can produce a horizontal alternating magnetic field to confine a molten metal at the edges of parallel horizontal rollers as a solid metal sheet is cast by counter-rotation of the rollers.

Sidewall containment of liquid metal with horizontal alternating magnetic fields

DOEpatents

Praeg, Walter F.

1995-01-01

An apparatus for confining molten metal with a horizontal alternating magnetic field. In particular, this invention employs a magnet that can produce a horizontal alternating magnetic field to confine a molten metal at the edges of parallel horizontal rollers as a solid metal sheet is cast by counter-rotation of the rollers.

78 FR 61443 - Small Business Size Standards: Waiver of the Nonmanufacturer Rule

Federal Register 2010, 2011, 2012, 2013, 2014

2013-10-03

... to rescind the Class Waiver of the Nonmanufacturer Rule (NMR) for Aerospace Ball and Roller Bearings... accessed by accessing the following URL: http://www.sba.gov/sites/default/files/files/NMR_WAIVED_3110... roller bearings manufactured by small businesses, unless an Individual Waiver of the NMR is granted by...

Methoprene influences reproduction and flight capacity in adults of the rice leaf roller, Cnaphalocrocis medinalis (Guenee) (Lepidoptera: Pyralidae)

USDA-ARS?s Scientific Manuscript database

Juvenile hormone (JH) influences many aspects of insect biology, including oogenesis-flight syndrome tradeoffs between migration and reproduction. Drawing on studies of many migratory insects, we posed the hypothesis that JH influences migratory capacity and oogenesis in the rice leaf roller, Cnapha...

Curves of Constant Width.

ERIC Educational Resources Information Center

Flaten, James A.

1999-01-01

Argues that it is possible to get a smooth ride on noncircular wheels on a smooth road if the load is supported using the wheels as rollers. Illustrates that the key to getting a smooth ride is for the rollers to measure the same height from top to bottom, regardless of how they are rotated. (CCM)

12. DETAIL LOOKING AT DOWNSTREAM APRON OF LOGWAY, WITH ROLLER ...

Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

12. DETAIL LOOKING AT DOWNSTREAM APRON OF LOGWAY, WITH ROLLER GATE TRACK IN RIGHT FOREGROUND, POWER PENSTOCK OUTLETS (WITH DRAFT TUBE CONTROL VENTS OVER) IN LEFT BACKGROUND AND NEW YORK CANAL IN EXTREME LEFT BACKGROUND. VIEW TO NORTHWEST. - Boise Project, Boise River Diversion Dam, Across Boise River, Boise, Ada County, ID

High Speed Cylindrical Roller Bearing Analysis, SKF Computer Program CYBEAN. Volume 1: Analysis

NASA Technical Reports Server (NTRS)

Kleckner, R. J.; Pirvics, J.

1978-01-01

The CYBEAN (CYlindrical BEaring ANalysis) program was created to detail radially loaded, aligned and misaligned Cylindrical roller bearing performance under a variety of operating conditions. The models and associated mathematics used within CYBEAN are described. The user is referred to the material for formulation assumptions and algorithm detail.

76 FR 76126 - Uncovered Innerspring Units from the People's Republic of China: Preliminary Results and...

Federal Register 2010, 2011, 2012, 2013, 2014

2011-12-06

... merchandise into the United States exported by Reztec. Consequently, we intend to rescind the review, in part... at 870; Tapered Roller Bearings and Parts Thereof, Finished and Unfinished, From Japan, and Tapered Roller Bearings, Four Inches or Less in Outside Diameter, and Components Thereof, From Japan; Preliminary...

An Analysis of US Emergency Department Visits From Falls From Skiing, Snowboarding, Skateboarding, Roller-Skating, and Using Nonmotorized Scooters.

PubMed

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. © The Author(s) 2015.

Effect of Silicon Nitride Balls and Rollers on Rolling Bearing Life

NASA Technical Reports Server (NTRS)

Zaretsky, Erwin V.; Vlcek, Brian L.; Hendricks, Robert C.

2005-01-01

Three decades have passed since the introduction of silicon nitride rollers and balls into conventional rolling-element bearings. For a given applied load, the contact (Hertz) stress in a hybrid bearing will be higher than an all-steel rolling-element bearing. The silicon nitride rolling-element life as well as the lives of the steel races were used to determine the resultant bearing life of both hybrid and all-steel bearings. Life factors were determined and reported for hybrid bearings. Under nominal operating speeds, the resultant calculated lives of the deep-groove, angular-contact, and cylindrical roller hybrid bearings with races made of post-1960 bearing steel increased by factors of 3.7, 3.2, and 5.5, respectively, from those calculated using the Lundberg-Palmgren equations. An all-steel bearing under the same load will have a longer life than the equivalent hybrid bearing under the same conditions. Under these conditions, hybrid bearings are predicted to have a lower fatigue life than all-steel bearings by 58 percent for deep-groove bearings, 41 percent for angular-contact bearings, and 28 percent for cylindrical roller bearings.

Design and Operating Characteristics of High-Speed, Small-Bore Cylindrical-Roller Bearings

NASA Technical Reports Server (NTRS)

Pinel, Stanley, I.; Signer, Hans R.; Zaretsky, Erwin V.

2000-01-01

The computer program SHABERTH was used to analyze 35-mm-bore cylindrical roller bearings designed and manufactured for high-speed turbomachinery applications. Parametric tests of the bearings were conducted on a high-speed, high-temperature bearing tester and the results were compared with the computer predictions. Bearings with a channeled inner ring were lubricated through the inner ring, while bearings with a channeled outer ring were lubricated with oil jets. Tests were run with and without outer-ring cooling. The predicted bearing life decreased with increasing speed because of increased contact stresses caused by centrifugal load. Lower temperatures, less roller skidding, and lower power losses were obtained with channeled inner rings. Power losses calculated by the SHABERTH computer program correlated reasonably well with the test results. The Parker formula for XCAV (used in SHABERTH as a measure of oil volume in the bearing cavity) needed to be adjusted to reflect the prevailing operating conditions. The XCAV formula will need to be further refined to reflect roller bearing lubrication, ring design, cage design, and location of the cage-controlling land.

Evaluation of a high-torque backlash-free roller actuator

NASA Technical Reports Server (NTRS)

Steinetz, Bruce M.; Rohn, Douglas A.; Anderson, William

1986-01-01

The results are presented of a test program that evaluated the stiffness, accuracy, torque ripple, frictional losses, and torque holding capability of a 16:1 ratio, 430 N-m (320 ft-lb) planetary roller drive for a potential space vehicle actuator application. The drive's planet roller supporting structure and bearings were found to be the largest contributors to overall drive compliance, accounting for more than half of the total. In comparison, the traction roller contacts themselves contributed only 9 percent of the drive's compliance based on an experimentally verified stiffness model. The drive exhibited no backlash although 8 arc sec of hysteresis deflection were recorded due to microcreep within the contact under torque load. Because of these load-dependent displacements, some form of feedback control would be required for arc second positioning applications. Torque ripple tests showed the drive to be extremely smooth, actually providing some damping of input torsional oscillations. The drive also demonstrated the ability to hold static torque with drifts of 7 arc sec or less over a 24 hr period at 35 percent of full load.

The Therapeutic Roller Coaster

PubMed Central

CHU, JAMES A.

1992-01-01

Survivors of severe childhood abuse often encounter profound difficulties. In addition to posttraumatic and dissociative symptomatology, abuse survivors frequently have characterologic problems, particularly regarding self-care and maintaining relationships. Backgrounds of abuse, abandonment, and betrayal are often recapitulated and reenacted in therapy, making the therapeutic experience arduous and confusing for therapists and patients. Efforts must be directed at building an adequate psychotherapeutic foundation before undertaking exploration and abreaction of past traumatic experiences. This discussion sets out a model for treatment of childhood abuse survivors, describing stages of treatment and suggesting interventions. Common treatment dilemmas or "traps" are discussed, with recommendations for their resolution. PMID:22700116

Effects of a Gentle, Self-Administered Stimulation of Perineal Skin for Nocturia in Elderly Women: A Randomized, Placebo-Controlled, Double-Blind Crossover Trial.

PubMed

Iimura, Kaori; Watanabe, Nobuhiro; Masunaga, Koichi; Miyazaki, Shogo; Hotta, Harumi; Kim, Hunkyung; Hisajima, Tatsuya; Takahashi, Hidenori; Kasuya, Yutaka

2016-01-01

Somatic afferent nerve stimuli are used for treating an overactive bladder (OAB), a major cause of nocturia in the elderly. Clinical evidence for this treatment is insufficient because of the lack of appropriate control stimuli. Recent studies on anesthetized animals show that gentle stimuli applied to perineal skin with a roller could inhibit micturition contractions depending on the roller's surface material. We examined the efficacy of gentle skin stimuli for treating nocturia. The study was a cross-over, placebo-controlled, double-blind randomized clinical study using two rollers with different effects on micturition contractions. Participants were elderly women (79-89 years) with nocturia. Active (soft elastomer roller) or placebo (hard polystyrene roller) stimuli were applied to perineal skin by participants for 1 min at bedtime. A 3-day baseline assessment period was followed by 3-day stimulation and 4-day resting periods, after which the participants were subjected to other stimuli for another 3 days. The primary outcome was change in the frequency of nighttime urination, for which charts were maintained during each 3-day period. Twenty-four participants were randomized, of which 22 completed all study protocols. One participant discontinued treatment because of an adverse event (abdominal discomfort). In participants with OAB (n = 9), change from baseline in the mean frequency of urination per night during the active stimuli period (mean ± standard deviation, -0.74 ± 0.7 times) was significantly greater than that during placebo stimuli periods (-0.15 ± 0.8 times [p < 0.05]). In contrast, this difference was not observed in participants without OAB (n = 13). These results suggest that gentle perineal stimulation with an elastomer roller is effective for treating OAB-associated nocturia in elderly women. Here the limitation was a study period too short to assess changes in the quality of sleep and life. UMIN Clinical Trial Registry (CTR) UMIN000015809.

Roller massage decreases spinal excitability to the soleus.

PubMed

Young, James D; Spence, Alyssa-Joy; Behm, David G

2018-04-01

Roller massage (RM) interventions have shown acute increases in range of motion (ROM) and pain pressure threshold (PPT). It is unclear whether the RM-induced increases can be attributed to changes in neural or muscle responses. The purpose of this study was to evaluate the effect of altered afferent input via application of RM on spinal excitability, as measured with the Hoffmann (H-) reflex. A randomized within-subjects design was used. Three 30-s bouts of RM were implemented on a rested, nonexercised, injury-free muscle with 30 s of rest between bouts. The researcher applied RM to the plantar flexors at three intensities of pain: high, moderate, and sham. Measures included normalized M-wave and H-reflex peak-to-peak amplitudes before, during, and up to 3 min postintervention. M-wave and H-reflex measures were highly reliable. RM resulted in significant decreases in soleus H-reflex amplitudes. High-intensity, moderate-intensity, and sham conditions decreased soleus H-reflex amplitudes by 58%, 43%, and 19%, respectively. H-reflexes induced with high-intensity rolling discomfort or pain were significantly lower than moderate and sham conditions. The effects were transient in nature, with an immediate return to baseline following RM. This is the first evidence of RM-induced modulation of spinal excitability. The intensity-dependent response observed indicates that rolling pressure or pain perception may play a role in modulation of the inhibition. Roller massage-induced neural modulation of spinal excitability may explain previously reported increases in ROM and PPT. NEW & NOTEWORTHY Recent evidence indicates that the benefits of foam rolling and roller massage are primarily accrued through neural mechanisms. The present study attempts to determine the neuromuscular response to roller massage interventions. We provide strong evidence of roller massage-induced neural modulation of spinal excitability to the soleus. It is plausible that reflex inhibition may explain subsequent increases in pain pressure threshold.

Mechanism for Deploying a Long, Thin-Film Antenna from a Rover

NASA Technical Reports Server (NTRS)

Lazio, Joseph; Matthews, B.; Nesnas, Issa A.; Zarzhitsky, Dimitri

2013-01-01

Observations with radio telescopes address key problems in cosmology, astrobiology, heliophysics, and planetary science including the first light in the Universe (Cosmic Dawn), magnetic fields of extrasolar planets, particle acceleration mechanisms, and the lunar ionosphere. The Moon is a unique science platform because it allows access to radio frequencies that do not penetrate the Earth's ionosphere and because its far side is shielded from intense terrestrial emissions. A radio antenna can be realized by using polyimide film as a substrate, with a conducting substance deposited on it. Such an antenna can be rolled into a small volume for transport, then deployed by unrolling, and a robotic rover offers a natural means of unrolling a polyimide film-based antenna. An antenna deployment mechanism was developed that allows a thin film to be deposited onto a ground surface, in a controlled manner, using a minimally actuated rover. The deployment mechanism consists of two rollers, one driven and one passive. The antenna film is wrapped around the driven roller. The passive roller is mounted on linear bearings that allow it to move radially with respect to the driven roller. Springs preload the passive roller against the driven roller, and prevent the tightly wrapped film from unspooling or "bird's nesting" on the driven spool. The antenna deployment mechanism is integrated on the minimally-actuated Axel rover. Axel is a two-wheeled rover platform with a trailing boom that is capable of traversing undulated terrain and overcoming obstacles of a wheel radius in height. It is operated by four motors: one that drives each wheel; a third that controls the rotation of the boom, which orients the body mounted sensors; and a fourth that controls the rover's spool to drive the antenna roller. This low-mass axle-like rover houses its control and communication avionics inside its cylindrical body. The Axel rover teleoperation software has an auto-spooling mode that allows a user to automatically deploy the thin-film antenna at a rate proportional to the wheel speed as it drives the rover along its trajectory. The software allows Axel to deposit the film onto the ground to prevent or minimize relative motion between the film and the terrain to avoid the risk of scraping and antenna with the terrain.

Occupational exposure to unburnt tobacco and potential risk of toxic optic neuropathy: A cross-sectional study among beedi rollers in selected rural areas of coastal Karnataka, India

PubMed Central

Naseer, Ansaba; Shivalli, Siddharudha; Arunachalam, Cynthia

2017-01-01

Background Beedi also known as poor man’s cigarette is manufactured in almost all major states of India. Beedi workers are exposed to various health risks. There is an increased risk of systemic absorption of tobacco through skin and mucous membrane. The optic nerve is susceptible to damage from several toxic substances including tobacco. This group of disorders is known as toxic optic neuropathy (TON). The association of TON with occupational exposure to unburnt tobacco in beedi rollers has not been explored. Objectives Among the beedi rollers in Mangaluru and Bantwal talukas of Dakshina Kannada District, Karnataka, India: to assess the magnitude of potential TON utilizing colour vision and contrast sensitivity as screening tools and to identify the demographic, biological and occupational factors associated with potential TON. Methods A community-based cross-sectional study was conducted from April-Sept 2016 in Mangaluru and Bantwal talukas, of Dakshina Kannada district, Karnataka. Beedi rollers from twelve villages (six from each taluka) were included. In each of the selected villages, the investigators identified beedi collection centres and all the eligible beedi rollers were included in the study till the required number of beedi rollers for that village was achieved. Participants were screened at the study site for visual acuity, colour vision and contrast sensitivity and those with abnormal colour and contrast sensitivity in the presence of good visual acuity were considered to have potential TON. Results A total of 377 beedi rollers were approached; of which 365 consented to take part in the study (response rate: 96.81%). Women constituted the majority of the participants (n = 338, 92.6%). Based on the screening criteria, the prevalence of potential TON was 17.5% (n = 64, 95% CI: 13.5–21.9). On multiple logistic regression analysis, duration of beedi rolling (Adj OR: 1.061; 95% CI 1.015–1.109, p = 0.009), advancing age (Adj OR: 1.096; 95% CI 1.058–1.136, p<0.001) and presence of diabetes (Adj OR: 6.315; 95% CI 1.4572–27.376, p = 0.014) were independent correlates of potential TON. Conclusion In the present study, almost one out of six beedi rollers displayed clinical signs of potential TON. Increased duration of beedi rolling, advancing age and presence of diabetes were the independent correlates of potential TON. However, with this cross-sectional study it is not possible to conclude if these factors play a role individually or collectively or are a serendipitous association, for which large scale analytical studies are required. PMID:29149211

Fault Detection of a Roller-Bearing System through the EMD of a Wavelet Denoised Signal

PubMed Central

Ahn, Jong-Hyo; Kwak, Dae-Ho; Koh, Bong-Hwan

2014-01-01

This paper investigates fault detection of a roller bearing system using a wavelet denoising scheme and proper orthogonal value (POV) of an intrinsic mode function (IMF) covariance matrix. The IMF of the bearing vibration signal is obtained through empirical mode decomposition (EMD). The signal screening process in the wavelet domain eliminates noise-corrupted portions that may lead to inaccurate prognosis of bearing conditions. We segmented the denoised bearing signal into several intervals, and decomposed each of them into IMFs. The first IMF of each segment is collected to become a covariance matrix for calculating the POV. We show that covariance matrices from healthy and damaged bearings exhibit different POV profiles, which can be a damage-sensitive feature. We also illustrate the conventional approach of feature extraction, of observing the kurtosis value of the measured signal, to compare the functionality of the proposed technique. The study demonstrates the feasibility of wavelet-based de-noising, and shows through laboratory experiments that tracking the proper orthogonal values of the covariance matrix of the IMF can be an effective and reliable measure for monitoring bearing fault. PMID:25196008

Electrohydrodynamic interactions in Quincke rotation: from pair dynamics to collective motion

NASA Astrophysics Data System (ADS)

Das, Debasish; Saintillan, David

2013-11-01

Weakly conducting dielectric particles suspended in a dielectric liquid can undergo spontaneous sustained rotation when placed in a sufficiently strong dc electric field. This phenomenon of Quincke rotation has interesting implications for the rheology of these suspensions whose effective viscosity can be reduced by application of an external field. While previous models based on the rotation of isolated particles have provided accurate estimates for this viscosity reduction in dilute suspensions discrepancies have been reported in more concentrated systems where particle-particle interactions are likely significant. Motivated by this observation we extend the classic description of Quincke rotation based on the Taylor-Melcher leaky dielectric model to account for pair electrohydrodynamic interactions between identical spheres using method of reflections. We also consider the case of spherical particles undergoing Quincke rotation next to a planar electrode, where hydrodynamic interactions with the no-slip boundary lead to a self-propelled velocity. The interactions between such Quincke rollers are analyzed, and a transition to collective motion is predicted in sufficiently dense collections of many rollers, in agreement with recent experiments.

Preliminary list of the leaf-roller moths (Insecta: Lepidoptera: Tortricidae) of Virginia with comments on spatial and temporal distribution

USDA-ARS?s Scientific Manuscript database

Based on the examination of 3,457 pinned specimens, we document 263 species of leaf-roller moths (Lepidoptera: Tortricidae) from the Commonwealth of Virginia. The vast majority of specimens examined are from five unrelated efforts: a survey of George Washington Memorial Parkway National Park, Fairfa...

Sidewall containment of liquid metal with horizontal alternating magnetic fields

DOEpatents

Praeg, W.F.

1995-01-31

An apparatus is disclosed for confining molten metal with a horizontal alternating magnetic field. In particular, this invention employs a magnet that can produce a horizontal alternating magnetic field to confine a molten metal at the edges of parallel horizontal rollers as a solid metal sheet is cast by counter-rotation of the rollers. 19 figs.

77 FR 2031 - Tapered Roller Bearings and Parts Thereof, Finished and Unfinished From the People's Republic of...

Federal Register 2010, 2011, 2012, 2013, 2014

2012-01-13

... Parts Thereof, Finished and Unfinished From the People's Republic of China: Extension of the Time Limit..., International Trade Administration, U.S. Department of Commerce, 14th Street and Constitution Avenue NW..., finished and unfinished from the People's Republic of China. See Tapered Roller Bearings and Parts Thereof...

Visualization in Mechanics: The Dynamics of an Unbalanced Roller

ERIC Educational Resources Information Center

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…

Condition Assessment Aspects of an Asset Management Program

DTIC Science & Technology

2008-01-01

of a roller gate..................................................................................................49 Figure 11. Torsion in a roller...each component of these structures (filters, drains , motors, wire rope, etc.). This is accomplished by a pre- developed framework that is tailored to...various types of miter gates to account for within the algorithm. Depending on the anchorage system (rigid versus flexible ) and whether the lock is

75 FR 844 - Tapered Roller Bearings and Parts Thereof, Finished and Unfinished, from the People's Republic of...

Federal Register 2010, 2011, 2012, 2013, 2014

2010-01-06

... pillow blocks) incorporating tapered rollers, with or without spindles, whether or not for automotive use... Department has made the following changes: We have revised the surrogate value for tube steel. See Issues and... Analysis Memorandum''). We have corrected the direct material calculation for bar and tube steel in our...

Spherical roller bearing analysis. SKF computer program SPHERBEAN. Volume 2: User's manual

NASA Technical Reports Server (NTRS)

Kleckner, R. J.; Dyba, G. J.

1980-01-01

The user's guide for the SPHERBEAN computer program for prediction of the thermomechanical performance characteristics of high speed lubricated double row spherical roller bearings is presented. The material presented is structured to guide the user in the practical and correct implementation of SPHERBEAN. Input and output, guidelines for program use, and sample executions are detailed.

75 FR 73128 - Certain Printing and Imaging Devices and Components Thereof; Notice of Commission Determination...

Federal Register 2010, 2011, 2012, 2013, 2014

2010-11-29

...'' include any line extending parallel to the central axis of the roller? Or, does this refer to the central... ``a longitudinal direction'' can include any line extending parallel to the central axis of the roller...) The finding that the Taylor reference (``A Telerobot on the World Wide Web'') (RX-281) does not...

75 FR 61747 - Coffin Butte Energy Park, LLC; Notice of Preliminary Permit Application Accepted for Filing and...

Federal Register 2010, 2011, 2012, 2013, 2014

2010-10-06

... Power Act (FPA), proposing to study the feasibility of the Coffin Butte Pumped Storage Water Power... triangular earth and roller compacted concrete embankment; creating a 50-acre upper reservoir with a storage...); (2) a 6,300-foot-long, 60-foot-high oval earth and roller compacted concrete embankment; creating a...

Study of device for precompaction and uniform supply of materials to working bodies of aggregate

NASA Astrophysics Data System (ADS)

Romanovich, A. A.; Kolesnikov, R. S.; Romanovich, M. A.

2018-03-01

The article considers perspective ways of increase of reliability and durability of the press roller grinder due to the uniform supply of crushed materials across the width of the rolls. The mechanism of distribution and pre- compaction of materials in a roller arrangement has been analytically studied, an equation has been derived for calculating the effort expended. The materials of the article are devoted to increasing the reliability of the press roller grinder due to the uniform supply of grindable materials along the width of the rolls and may be of interest to Russian and foreign organizations that carry out their activities in the field of exploitation, designing and manufacturing of crushing and grinding equipment.

Method and apparatus for corrugating strips

DOEpatents

Day, Jack R.; Curtis, Charles H.

1983-01-01

The invention relates to a method and a machine for transversely corrugating a continuous strip of metallic foil. The product foil comprises a succession of alternately disposed corrugations, each defining in cross section, a major segment of a circle. The foil to be corrugated is positioned to extend within a vertical passage in the machine. The walls of the passage are heated to promote the desired deformation of the foil. Foil-deforming rollers are alternately passed obliquely across the passage to respectively engage transverse sections of the foil. The rollers and their respective section of deformed foil comprise a stacked assembly which is moved incrementally through the heated passageway. As the assembly emerges from the passageway, the rollers spill from the corrugated foil and are recovered for re-use.

Magnetic bearings for a high-performance optical disk buffer

NASA Technical Reports Server (NTRS)

Hockney, Richard; Hawkey, Timothy

1993-01-01

An optical disk buffer concept can provide gigabit-per-second data rates and terabit capacity through the use of arrays of solid state lasers applied to a stack of erasable/reusable optical disks. The RCA optical disk buffer has evoked interest by NASA for space applications. The porous graphite air bearings in the rotary spindle as well as those used in the linear translation of the read/write head would be replaced by magnetic bearings or mechanical (ball or roller) bearings. Based upon past experience, roller or ball bearings for the translation stages are not feasible. Unsatisfactory, although limited experience exists with ball bearing spindles also. Magnetic bearings, however, appear ideally suited for both applications. The use of magnetic bearings is advantageous in the optical disk buffer because of the absence of physical contact between the rotating and stationary members. This frictionless operation leads to extended life and reduced drag. The manufacturing tolerances that are required to fabricate magnetic bearings would also be relaxed from those required for precision ball and gas bearings. Since magnetic bearings require no lubricant, they are inherently compatible with a space (vacuum) environment. Magnetic bearings also allow the dynamics of the rotor/bearing system to be altered through the use of active control. This provides the potential for reduced vibration, extended regions of stable operation, and more precise control of position.

Quantitative evaluation of hand cranking a roller pump in a crisis management drill.

PubMed

Tomizawa, Yasuko; Tokumine, Asako; Ninomiya, Shinji; Momose, Naoki; Matayoshi, Toru

2008-01-01

The heart-lung machines for open-heart surgery have improved over the past 50 years; they rarely break down and are almost always equipped with backup batteries. The hand-cranking procedure only becomes necessary when a pump breaks down during perfusion or after the batteries have run out. In this study, the performance of hand cranking a roller pump was quantitatively assessed by an objective method using the ECCSIM-Lite educational simulator system. A roller pump connected to an extracorporeal circuit with an oxygenator and with gravity venous drainage was used. A flow sensor unit consisting of electromagnetic sensors was used to measure arterial and venous flow rates, and a built-in pressure sensor was used to measure the water level in the reservoir. A preliminary study of continuous cranking by a team of six people was conducted as a surprise drill. This system was then used at a perfusion seminar. At the seminar, 1-min hand-cranking drills were conducted by volunteers according to a prepared scenario. The data were calculated on site and trend graphs of individual performances were given to the participants as a handout. Preliminary studies showed that each person's performance was different. Results from 1-min drills showed that good performance was not related to the number of clinical cases experienced, years of practice, or experience in hand cranking. Hand cranking to maintain the target flow rate could be achieved without practice; however, manipulating the venous return clamp requires practice. While the necessity of performing hand cranking during perfusion due to pump failure is rare, we believe that it is beneficial for perfusionists and patients to include hand-cranking practice in periodic extracorporeal circulation crisis management drills because a drill allows perfusionists to mentally rehearse the procedures should such a crisis occur.

Development of a paper based roll-to-roll nanoimprinting machine

NASA Astrophysics Data System (ADS)

Son, Byungwook

Nanoimprint lithography (NIL) has been developed and studied since 1995. It is a technique where micro- or nanoscale patterns are transferred to soft materials such as polymer through pressing a stamp with certain patterns into this materials and then solidifying it by cooling at lower temperature or curing under ultra violet excitement. High Cost and low throughput of batch mode nanoimprint lithography (NIL) processes are limiting its wide range of applications in meeting industry manufacturing requirements. The roll-to-roll (R2R) nanoimprinting technology is emerged as a solution to this issue. This thesis study presents the design, build and test of an innovative R2R T-NIL process machine for nanofabrication and MEMS fabrication applications, which consists of individual modules of heating, inking, pressuring, and rotational speed control. The system utilizes PDMS as mold material, PMMA as imprinting material, and paper as substrate material. In order to achieve a uniform pressure on PMMA during imprinting process, an innovative air pressure device (APD) was developed and integrated with R2R machine. The APD replaces the conventional 2-roll line contact pressure approach and can cover one third of the surface of the imprinting roller with a uniform pressure (1-3 psi). During the imprinting experiment, a mixture of PMMA (20w %) and 2-Ethoxyethyl acetate is applied on the paper substrate by an inking roller using capillary force and an IR heater is used for pre-heating and drying of polymer layers before it is fed into the imprinting module. Two 500-Watt cartridge heaters are installed on the roller and provide the heat to raise the PMMA film temperature during the imprinting.

Becoming a father is an emotional roller coaster - an analysis of first-time fathers' blogs.

PubMed

Asenhed, Liselotte; Kilstam, Jennie; Alehagen, Siw; Baggens, Christina

2014-05-01

To identify and describe the process of fatherhood during the partner's pregnancy among expectant, first-time fathers. Pregnancy seems to be a demanding period for expectant fathers, and this period is a part of their transition to fatherhood. Blogs can be seen as personal diaries and offer an alternative method of collecting data as they are an arena for sharing experiences and narratives. An explorative qualitative design. Blogs from the Internet by eleven first-time fathers living in Sweden were included in the study. Qualitative content analysis was used for the analysis of the blogs. A theme emerged expressing the latent content of the text: 'Becoming a father for the first time is an emotional roller coaster where the role of the expectant father is not obvious' and five different categories describing the manifest content: the pregnancy, a new life, to make the child real, preparations for the delivery and the arrival of the child, and a new role in life. The metaphor 'roller coaster' indicates the tension between different feelings about the men's future as fathers. They are searching for answers on how to be a good father. They feel excluded when they visit antenatal care centres and have difficulties finding out how to support their partner. This is an existential period when they understand themselves as adults and also miss relatives who have died. During pregnancy, the men start to communicate with their child, and this interaction gives a sense of reality and creates hope and joy about being a father. Staff involved in antenatal care can use the knowledge from this study when meeting with expectant fathers. Perspectives expressed in blogs may enhance the professionals' understanding that the transition process of fatherhood is complex. © 2013 John Wiley & Sons Ltd.

Influence of ambient moisture on the compaction behavior of microcrystalline cellulose powder undergoing uni-axial compression and roller-compaction: a comparative study using near-infrared spectroscopy.

PubMed

Gupta, Abhay; Peck, Garnet E; Miller, Ronald W; Morris, Kenneth R

2005-10-01

This study evaluates the effect of variation in the ambient moisture on the compaction behavior of microcrystalline cellulose (MCC) powder. The study was conducted by comparing the physico-mechanical properties of, and the near infrared (NIR) spectra collected on, compacts prepared by roller compaction with those collected on simulated ribbons, that is, compacts prepared under uni-axial compression. Relative density, moisture content, tensile strength (TS), and Young modulus were used as key sample attributes for comparison. Samples prepared at constant roller compactor settings and feed mass showed constant density and a decrease in TS with increasing moisture content. Compacts prepared under uni-axial compression at constant pressure and compact mass showed the opposite effect, that is, density increased while TS remained almost constant with increasing moisture content. This suggests difference in the influence of moisture on the material under roller compaction, in which the roll gap (i.e., thickness and therefore density) remains almost constant, vs. under uni-axial compression, in which the thickness is free to change in response to the applied pressure. Key sample attributes were also related to the NIR spectra using multivariate data analysis by the partial least squares projection to latent structures (PLS). Good agreement was observed between the measured and the NIR-PLS predicted values for all key attributes for both, the roller compacted samples as well as the simulated ribbons. Copyright (c) 2005 Wiley-Liss, Inc. and the American Pharmacists Association

Preliminary evaluation of steel-roller round baler for woody biomass baling

Treesearch

B. J. Stokes; D. L. Sirois; S. L. Woodfin

1987-01-01

A round hay baler with little modification was used to bale small-diameter, crushed trees. The trees had been crushed using a series of compression rollers. Bale cores had to be developed by hand before the baler became self-feeding. Windrowed material was packed off the ground by the baler system after a core had been developed.

77 FR 65668 - Tapered Roller Bearings and Parts Thereof, Finished and Unfinished From the People's Republic of...

Federal Register 2010, 2011, 2012, 2013, 2014

2012-10-30

...) incorporating tapered rollers, with or without spindles, whether or not for automotive use. These products are... steel scrap by-product. We intended to grant an offset for this byproduct but made a clerical error in the Preliminary Results by not granting an offset for the steel scrap but rather, adding it to direct...

Apparatus for efficient sidewall containment of molten metal with horizontal alternating magnetic fields utilizing low reluctance rims

DOEpatents

Praeg, Walter F.

1999-01-01

A method and apparatus for casting sheets of metal from molten metal. The apparatus includes a containment structure having an open side, a horizontal alternating magnetic field generating structure and rollers including low reluctance rim structures. The magnetic field and the rollers help contain the molten metal from leaking out of the containment structure.

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

NASA Technical Reports Server (NTRS)

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.

Stopping a Roller Coaster Train

ERIC Educational Resources Information Center

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…

One City, Two Worlds, and Yet...: New York from "Roller Skates" to "Stevie."

ERIC Educational Resources Information Center

Hendrickson, Linnea

1998-01-01

Explores Ruth Sawyer's "Roller Skates" and John Steptoe's "Stevie"--two very different works linked by common themes and settings. Concludes that these works portray children exploring the variety and richness of life in New York City of the 1890s and of the 1960s, and that both emphasize the importance of love, family, and…

Water removal of wet veneer by roller pressing

Treesearch

Koji Adachi; Masafumi Inoue; Kozo Kanayama; Roger M. Rowell; Shuichi Kawai

2004-01-01

High moisture content, flat sawn Japanese cedar (Cryptomeria japonica D. Don) veneer was compressed using a roller press to mechanically remove water. The amount of water removed depended on the amount of compression applied. At 60% compression, 400 kg/m3 of water was removed. The process was not dependent on the size of the wood, the degree of compression, or the feed...

75 FR 9391 - Tapered Roller Bearings and Parts Thereof, Finished or Unfinished, from the People's Republic of...

Federal Register 2010, 2011, 2012, 2013, 2014

2010-03-02

... Parts Thereof, Finished or Unfinished, from the People's Republic of China: Extension of Time Limit for... review of the antidumping duty order on tapered roller bearings and parts thereof, finished or unfinished... March 9, 2010. Statutory Time Limits Section 751(a)(3)(A) of the Tariff Act of 1930, as amended (``the...

Scale up of diesel oil biodegradation in a baffled roller bioreactor.

PubMed

Nikakhtari, Hossein; Song, Wanning; Kumar, Pardeep; Nemati, Mehdi; Hill, Gordon A

2010-05-01

Diesel oil is a suitable substance to represent petroleum contamination from accidental spills in operating and transportation facilities. Using a microbial culture enriched from a petroleum contaminated soil, biodegradation of diesel oil was carried out in 2.2, 55, and 220 L roller baffled bioreactors. The effects of bioreactor rotation speed (from 5 to 45 rpm) and liquid loading (from 18% to 73% of total volume) on the biodegradation of diesel oil were studied. In the small scale bioreactor (2.2L), the maximum rotation speed of 45 rpm resulted in the highest biodegradation rate with a first order biodegradation kinetic constant of 0.095 d(-1). In the larger scale bioreactors, rotation speed did not affect the biodegradation rate. Liquid loadings higher than 64% resulted in reduced biodegradation rates in the small scale bioreactor; however, in the larger roller bioreactors liquid loading did not affect the biodegradation rate. Biodegradation of diesel oil at 5 rpm and 73% loading is recommended for operating large scale roller baffled bioreactors. Under these conditions, high diesel oil concentrations up to 50 gL(-1) can be bioremediated at a rate of 1.61 gL(-1)d(-1). Copyright 2010 Elsevier Ltd. All rights reserved.

Effects of frequency on gross efficiency and performance in roller ski skating.

PubMed

Leirdal, S; Sandbakk, O; Ettema, G

2013-06-01

The purpose of the present study was to examine the effect of frequency on efficiency and performance during G3 roller ski skating. Eight well-trained male cross-country skiers performed three submaximal 5-min speeds (10, 13, and 16 km/h) and a time-to-exhaustion (TTE) performance (at 20 km/h) using the G3 skating technique using freely chosen, high, and low frequency at all four speeds. All tests were done using roller skis on a large treadmill at 5% incline. Gross efficiency (GE) was calculated as power divided by metabolic rate. Power was calculated as the sum of power against frictional forces and power against gravity. Metabolic rate was calculated from oxygen consumption and blood lactate concentration. Freely chosen frequency increased from 60 to 70 strokes/min as speed increased from 10 to 20 km/h. GE increased with power. At high power (20 km/h performance test), both efficiency and performance were significantly reduced by high frequency. In regard to choice of frequency during G3 roller ski skating, cross-country skiers seems to be self-optimized both in relation to energy saving (efficiency) and performance (TTE). © 2011 John Wiley & Sons A/S.

Feasibility study of a discrete bearing/roller drive rotary joint for the space station

NASA Technical Reports Server (NTRS)

Loewenthal, S. H.; Schuller, F. T.

1986-01-01

The most critical mechanism on board the proposed space station is the continously rotating joint which must accurately align the solar power units with the sun during earth orbit. The feasibility of a multiple, discrete bearing supported joint driven by a self-loading, pinch drive actuator was investigated for this application. This concept appears to offer greater protection against catastrophic jamming, less sensitivity to adverse thermal gradients, greater accessibility to inorbit servicing or replacement and greater adaptability to very large (5 m) truss members than to more conventional continuous support bearing/gear reducer joints. Analytical trade studies performed herein establish that a discrete cam roller bearing support system having eight hangers around a continuous ring would provide sufficient radial and bending stiffness to prevent any degradation in the fundamental frequencies of the solar wing structure. Furthermore, it appears that the pinch roller drive mechanism can be readily sized to meet or exceed system performance and service life requirements. Wear life estimates based on experimental data for a steel roller coated with an advanced polyimide film show a continuous service life more than two orders of magnitude greater than required for this application.

Effect of the variation in the ambient moisture on the compaction behavior of powder undergoing roller-compaction and on the characteristics of tablets produced from the post-milled granules.

PubMed

Gupta, Abhay; Peck, Garnet E; Miller, Ronald W; Morris, Kenneth R

2005-10-01

Effect of variation in the ambient moisture levels on the compaction behavior of a 10% acetaminophen (APAP) powder blend in microcrystalline cellulose (MCC) powder was studied by comparing the physical and mechanical properties of ribbons prepared by roller compaction with those of simulated ribbons, i.e., tablets prepared under uni-axial compression. Relative density, moisture content, tensile strength, and Young's modulus were used as key compact properties for comparison. Moisture was found to facilitate the particle rearrangement of both, the APAP and the MCC particles, as well as the deformation of the MCC particles. The tensile strength of the simulated ribbons also showed an increase with increasing moisture content. An interesting observation was that the tensile strength of the roller compacted samples first increased and then decreased with increasing moisture content. Variation in the ambient moisture during roller compaction was also found to influence the characteristics of tablets produced from the granules obtained post-milling the ribbons. A method to study this influence is also reported. Copyright (c) 2005 Wiley-Liss, Inc. and the American Pharmacists Association

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

PubMed

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.

Spread prediction model of continuous steel tube based on BP neural network

NASA Astrophysics Data System (ADS)

Zhai, Jian-wei; Yu, Hui; Zou, Hai-bei; Wang, San-zhong; Liu, Li-gang

2017-07-01

According to the geometric pass of roll and technological parameters of three-roller continuous mandrel rolling mill in a factory, a finite element model is established to simulate the continuous rolling process of seamless steel tube, and the reliability of finite element model is verified by comparing with the simulation results and actual results of rolling force, wall thickness and outer diameter of the tube. The effect of roller reduction, roller rotation speed and blooming temperature on the spread rule is studied. Based on BP(Back Propagation) neural network technology, a spread prediction model of continuous rolling tube is established for training wall thickness coefficient and spread coefficient of the continuous rolling tube, and the rapid and accurate prediction of continuous rolling tube size is realized.

Roller skating accidents and injuries.

PubMed

Sedlin, E D; Zitner, D T; McGinniss, G

1984-02-01

A consecutive series of 65 fractures, dislocations, and ligament tears produced by roller skating accidents treated by the Orthopaedic Department of the Mt. Sinai Services at City Hospital Center of Elmhurst, New York, is reviewed. It was learned that the injuries resulting from collisions occurring in a skating rink were more serious than those resulting from street accidents. Data indicated that lack of expertise is a prominent factor in the production of serious injury. However, the sport has inherent risk which is not eliminated by expertise. It was concluded that roller skating can and does produce disabling injuries. In order to reduce the number of injuries it will be required to reduce crowding in rinks, designate separate beginners' areas, use training wheels or clampon-type of skates when learning, encourage lessons, and separate beginners in the rinks.

Method and apparatus for corrugating strips

DOEpatents

Day, J.R.; Curtis, C.H.

1981-10-27

The invention relates to a method and a machine for transversely corrugating a continuous strip of metallic foil. The product foil comprises a succession of alternately disposed corrugations, each defining in a cross section, a major segment of a circle. The foil to be corrugated is positioned to extend within a vertical passage in the machine. The walls of the passage are heated to promote the desired deformation of the foil. Foil-deforming rollers are alternately passed obliquely across the passage to respectively engage transverse sections of the foil. The rollers and their respective section of deformed foil comprise a stacked assembly which is moved incrementally through the heated passageway. As the assembly emerges from the passageway, the rollers spill from the corrugated foil and are recovered for re-use.

CAM/LIFTER forces and friction

DOE Office of Scientific and Technical Information (OSTI.GOV)

Gabbey, D.J.; Lee, J.; Patterson, D.J.

1992-02-01

This report details the procedures used to measure the cam/lifter forces and friction. The present effort employed a Cummins LTA-10, and focuses on measurements and dynamic modeling of the injector train. The program was sponsored by the US Department of Energy in support of advanced diesel engine technology. The injector train was instrumented to record the instantaneous roller speed, roller pin friction torque, pushrod force, injector link force and cam speed. These measurements, together with lift profiles for pushrod and injector link displacement, enabled the friction work loss in the injector train to be determined. Other significant design criteria suchmore » as camshaft roller follower slippage and maximum loads on components were also determined. Future efforts will concentrate on the dynamic model, with tests run as required for correlation.« less

Comparison of High-Speed Operating Characteristics of Size 215 Cylindrical-Roller Bearings as Determined in Turbojet Engine and in Laboratory Test Rig

NASA Technical Reports Server (NTRS)

Macks, E Fred; Nemeth, Zolton N

1952-01-01

A comparison of the operating characteristics of 75-millimeter-bore (size 215) cylindrical-roller one-piece inner-race-riding cage-type bearings was made by means of a laboratory test rig and a turbojet engine. Cooling correlation parameters were determined by means of dimensional analysis, and the generalized results for both the inner- and the outer-race bearing operating temperatures are computed for the laboratory test rig and the turbojet engine. A method is given that enables the designer to predict the inner- and outer-race turbine roller-bearing temperatures from single curves, regardless of variations in speed, load, oil flow, oil inlet temperature, oil inlet viscosity, oil-jet diameter, or any combination of these parameters.

Experience of Application of Liquid Lubricating Materials during Wide Strip Hot Rolling

NASA Astrophysics Data System (ADS)

Platov, S. I.; Dema, R. R.; Kharchenko, M. V.; Amirov, R. N.

2017-12-01

The paper presents the results of the scientific and practical research of roller systems operation at feed of liquid lubricating materials through the example of the wide strip hot rolling Mill-2000 at PAO MMK. The experiments proved that application of lubricating materials leads to decrease of energy-power parameters of the process by 12 to 15 %, and reduction of work roll wear by 10 to 12%. The practical results of the study are developed recommendations on determination of consumption-volumetric parameters of the supplied lubricating material depending on rheological and geometrical parameters of the rolled strip and current wear of work rolls.

A comprehensive dynamic model of double-row spherical roller bearing—Model development and case studies on surface defects, preloads, and radial clearance

NASA Astrophysics Data System (ADS)

Cao, M.; Xiao, J.

2008-02-01

Bearing excitation is one of the most important mechanical sources for vibration and noise generation in machine systems of a broad range of industries. Although extensively investigated, accurately predicting the vibration/acoustic behavior of bearings remains a challenging task because of its complicated nonlinear behaviors. While some ground work has been laid out on single-row deep-grooved ball (DGB) bearing, comprehensive modeling effort on spherical roller bearing (SRB) has yet to be carried out. This is mainly due to the facts that SRB system carries one more extra degree of freedom (DOF) on the moving race (could be either inner or outer race) and in general has more rolling elements compared with DGB. In this study, a comprehensive SRB excitation source model is developed. In addition to the vertical and horizontal displacements considered in previous investigations, the impacts of axial displacement/load are addressed by introducing the DOF in the axial shaft direction. Hence, instead of being treated as pre-assumed constants, the roller-inner/outer race contact angles are formulated as functions of the axial displacement of the moving race to reflect their dependence on the axial movement. The approach presented in this paper accounts for the point contacts between rollers and inner/outer races, as well as line contacts when the loads on individual rollers exceed the limit for point contact. A detailed contact-damping model reflecting the influences of the surface profiles and the speeds of the both contacting elements is developed and applied in the SRB model. Waviness of all the contact surfaces (including inner race, outer race, and rollers) is included and compared in this analysis. Extensive case studies are carried out to reveal the impacts of surface waviness, radial clearance, surface defects, and loading conditions on the force and displacement responses of the SRB system. System design guidelines are recommended based on the simulation results. This model is also applicable for bearing health monitoring, as demonstrated by the numerical case studies showing the frequency response of the system with moderate-to-large point defects on both inner and outer races, as well as the rollers. Comparisons between the simulation results and some conclusions reflecting common sense available in open literature serves as first hand partial validation of the developed model. Future validation efforts and further improvement directions are also provided. The comprehensive model developed in this investigation is a useful tool for machine system design, optimization, and performance evaluation.

2012 DoD Historic Building Workshop: After-Action Report for Legacy Project # 10-387

DTIC Science & Technology

2012-09-01

Figure 16). The Thurs- day event was at the Giant Dipper roller coaster in Belmont Park, Califor- nia. ERDC/CERL SR-12-12 15 Figure 15. HBW...experiences and lessons learned as well as conversation about possible solutions. The format was the big difference between the 2008 HBC and 2012 HBW...additional cost, identify locations that can accommodate a large crowd for op- tional evening gatherings or happy hour. The gatherings were a big hit

29. Photocopy of photograph of the West Side Milling District, ...

Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

29. Photocopy of photograph of the West Side Milling District, dated 1912, original filed as MH5.9/NP1h/p14 in Audio-visual Collection of Minnesota Historical Society, St. Paul; SHOWS CROWN ROLLER MILL (THREE-QUARTER VIEW OF SOUTH AND WEST SIDES); LOOKING NORTHEAST - Crown Roller Mill, 105 Fifth Avenue, South, West Side Milling District, Minneapolis, Hennepin County, MN

9. VIEW OF MOLTEN SALT BATH EQUIPMENT AND ROLLER PRESSES ...

Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

9. VIEW OF MOLTEN SALT BATH EQUIPMENT AND ROLLER PRESSES BEING INSTALLED ON THE WEST SIDE (SIDE B) OF BUILDING 883. SIDE B OF BUILDING 883 WAS USED TO PROCESS ENRICHED URANIUM FROM 1957-66. (1/23/57) - Rocky Flats Plant, Uranium Rolling & Forming Operations, Southeast section of plant, southeast quadrant of intersection of Central Avenue & Eighth Street, Golden, Jefferson County, CO

"U.S.R.S., Grand Valley Project, Colo. Sprocket, shaft and chain for ...

Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

"U.S.R.S., Grand Valley Project, Colo. Sprocket, shaft and chain for 70 ft. roller hoist. May 14, 1915." Note that on this and other working drawings of the roller gates, the German manufacturer/patent holder is not acknowledged - Grand Valley Diversion Dam, Half a mile north of intersection of I-70 & Colorado State Route 65, Cameo, Mesa County, CO

Roller compaction: Effect of relative humidity of lactose powder.

PubMed

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 product. Copyright © 2016 Elsevier B.V. All rights reserved.

A fuel-based approach for emission factor development for highway paving construction equipment in China.

PubMed

Li, Zhen; Zhang, Kaishan; Pang, Kaili; Di, Baofeng

2016-12-01

The objective of this paper is to develop and demonstrate a fuel-based approach for emissions factor estimation for highway paving construction equipment in China for better accuracy. A highway construction site in Chengdu was selected for this study with NO emissions being characterized and demonstrated. Four commonly used paving equipment, i.e., three rollers and one paver were selected in this study. A portable emission measurement system (PEMS) was developed and used for emission measurements of selected equipment during real-world highway construction duties. Three duty modes were defined to characterize the NO emissions, i.e., idling, moving, and working. In order to develop a representative emission factor for these highway construction equipment, composite emission factors were estimated using modal emission rates and the corresponding modal durations in the process of typical construction duties. Depending on duty mode and equipment type, NO emission rate ranged from 2.6-63.7mg/s and 6.0-55.6g/kg-fuel with the fuel consumption ranging from 0.31-4.52 g/s correspondingly. The NO composite emission factor was estimated to be 9-41mg/s with the single-drum roller being the highest and double-drum roller being the lowest and 6-30g/kg-fuel with the pneumatic tire roller being the highest while the double-drum roller being the lowest. For the paver, both time-based and fuel consumption-based NO composite emission rates are higher than all of the rollers with 56mg/s and 30g/kg-fuel, respectively. In terms of time-based quantity, the working mode contributes more than the other modes with idling being the least for both emissions and fuel consumption. In contrast, the fuel-based emission rate appears to have less variability in emissions. Thus, in order to estimate emission factors for emission inventory development, the fuel-based emission factor may be selected for better accuracy. The fuel-based composite emissions factors will be less variable and more accurate than time-based emission factors. As a consequence, emissions inventory developed using this approach will be more accurate and practical.

The Lived Experience of Childbearing From Survivors of Sexual Abuse: "It Was the Best of Times, It Was the Worst of Times".

PubMed

LoGiudice, Jenna A; Beck, Cheryl T

2016-07-01

In the United States, one in every 5 women will experience sexual violence. Survivors are at risk for difficult pregnancies, substance abuse, stress, fear, and preterm births. A history of sexual abuse can impact several aspects of a woman's childbirth, thereby affecting her long-term physical and emotional well-being. The adverse pregnancy outcomes, combined with the prevalence of sexual abuse, underscore the need for research to understand survivors' experiences. This study's purpose was to understand the lived experience of pregnancy, labor, and birth from survivors. A qualitative, descriptive phenomenological research design was utilized. The purposeful sample included 8 female, self-identifying survivors of sexual abuse with at least one childbearing experience. Analysis identified 302 significant statements that formed 7 overarching themes: 1) No one asked me. Just ask me!; 2) An emotional roller coaster: From excitement to grief for what could have been a better experience; 3) All of a sudden I was that little girl again and/or I compartmentalized it: The all-or-nothing experience; 4) Am I even here?: Nothing was explained and I had no voice; 5) All too familiar: No support, nowhere to turn; 6) Holding on to the choices I can make: Who my doctor is and how I feed my baby; and 7) Overprotection: Keeping my child safe. The final result was the essence of childbearing for survivors in this study. They were not screened for a history of sexual abuse. Enjoyment and excitement were juxtaposed with guilt and fear. They had no voice, lacked support, and overwhelmingly desired control. They overprotected their children, from infancy into adulthood. The childbearing experience was a complex, emotional roller coaster permeated by the past. Women's health care providers can utilize the results to provide therapeutic care to survivors to prevent revictimization. The results elucidate the importance of screening for a history of sexual abuse and discussing the implications such a history can have on the childbearing experience. © 2016 by the American College of Nurse-Midwives.

Neuromuscular Responses of Elite Skaters During Different Roller Figure Skating Jumps

PubMed Central

Pantoja, Patrícia Dias; Mello, André; Liedtke, Giane Veiga; Kanitz, Ana Carolina; Cadore, Eduardo Lusa; Pinto, Stephanie Santana; Alberton, Cristine Lima; Kruel, Luiz Fernando Martins

2014-01-01

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. PMID:25114728

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

NASA Technical Reports Server (NTRS)

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.

Effect of Internal Clearance on Load Distribution and Life of Radially Loaded Ball and Roller Bearings

NASA Technical Reports Server (NTRS)

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

2012-01-01

The effect of internal clearance on radially loaded deepgroove ball and cylindrical roller bearing load distribution and fatigue life was determined for four clearance groups defined in the bearing standards. The analysis was extended to negative clearance (interference) conditions to produce a curve of life factor versus internal clearance. Rolling-element loads can be optimized and bearing life maximized for a small negative operating clearance. Life declines gradually with positive clearance and rapidly with increasing negative clearance. Relationships were found between bearing life and internal clearance as a function of ball or roller diameter, adjusted for load. Results are presented as life factors for radially loaded bearings independent of bearing size or applied load. In addition, a modified Stribeck Equation is presented that relates the maximum rolling-element load to internal bearing clearance.

CAM/LIFTER forces and friction. Final report, September 15, 1988--November 30, 1991

DOE Office of Scientific and Technical Information (OSTI.GOV)

Gabbey, D.J.; Lee, J.; Patterson, D.J.

1992-02-01

This report details the procedures used to measure the cam/lifter forces and friction. The present effort employed a Cummins LTA-10, and focuses on measurements and dynamic modeling of the injector train. The program was sponsored by the US Department of Energy in support of advanced diesel engine technology. The injector train was instrumented to record the instantaneous roller speed, roller pin friction torque, pushrod force, injector link force and cam speed. These measurements, together with lift profiles for pushrod and injector link displacement, enabled the friction work loss in the injector train to be determined. Other significant design criteria suchmore » as camshaft roller follower slippage and maximum loads on components were also determined. Future efforts will concentrate on the dynamic model, with tests run as required for correlation.« less

Low-frequency vibrations of a cylindrical shell rotating on rollers

NASA Astrophysics Data System (ADS)

Filippov, S. B.

2018-05-01

Small free low-frequency vibrations of a rotating closed cylindrical shell which is in a contact with rigid cylindrical rollers are considered. Assumptions of semi-momentless shell theory are used. By means of the expansion of solutions in truncated Fourier series in circumference coordinate the system of the algebraic equations for the approximate calculation of the vibration frequencies and the mode shapes is obtained. The algorithm for the evaluation of frequencies and vibration modes based on analytical solution is developed. In particular, the lowest frequencies of thin cylindrical shell, representing greatest interest for applications, were found. Approximate results are compared with results of numerical calculations carried out by the Finite Elements Analysis. It is shown that the semi-momentless theory can be used for the evaluation of the low frequencies of a cylindrical shell rotating on rollers.

Studies of The Durability of Belt Conveyor Idlers with Working Loads Taken into Account

NASA Astrophysics Data System (ADS)

Król, Robert

2017-12-01

The results of laboratory and operational studies conducted in the Machinery Systems Division of Wroclaw University of Technology in recent years have became the basis for selecting proper belt conveyor roller designs optimized for specific strength and operational criteria. The usefulness of the results for assessing the energy intensity of idlers, estimating their durability and determining modernization policies has been confirmed. Methods of estimating the durability of carrying idlers on the basis of the identified output stream distributions are presented. Results of studies carried out using an analytical method and a laboratory method are reported. It has been shown that the operational durability of a roller is determined by its design, the roller set parameters (the spacing and the angle of bevel) and the operating conditions having a bearing on the irregularity of the transported output stream.

Lubrication of optimized-design tapered-roller bearings to 2.4 million DN

NASA Technical Reports Server (NTRS)

Parker, R. J.; Pinel, S. I.; Signer, Hans R.

1980-01-01

The performance of 120.65 mm (4.75 in.) bore high speed design, tapered roller bearings was investigated at shaft speeds to 20,000 rpm (2.4 million DN) under combined thrust and radial load. The test bearing design was computer optimized for high speed operation. Temperature distribution bearing heat generation were determined as a function of shaft speed, radial and thrust loads, lubricant flow rates, and lubricant inlet temperature. The high speed design, tapered roller bearing operated successfully at shaft speeds up to 20,000 rpm under heavy thrust and radial loads. Bearing temperatures and heat generation with the high speed design bearing were significantly less than those of a modified standard bearing tested previously. Cup cooling was effective in decreasing the high cup temperatures to levels equal to the cone temperature.

Construction Foundation Report, Grand River, Bowman-Haley Project, North Dakota. Volume 1. Text, Drawings, Photos.

DTIC Science & Technology

1985-05-01

tamping rollers. Final compaction was by rubber -t ired rollers. Compaction was to 95% of maximum density. Time between placing the 6" layers and...taree ue go dscribe*he:. 0 IoldNYeRAEL Boreast ol bsnc of eater readngs in the Iiraphic Log ’G I CAYI CQ 5A esL.- ADS@ * nbr ; i cneeeiItt be oetrued O

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

ERIC Educational Resources Information Center

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…

Development of Mainshaft High-Speed Cylindrical Roller Bearings for Gas Turbine Engines.

DTIC Science & Technology

1978-10-01

roller motion, that calculation may then be eliminated for subsequent, similar runs. TIhis option provides the user a corresponding savings in computer...to W BEARING DN X !0.6 Figl"re 2..’ Test of Grou p-N Bearing No, ,5 Shows" Increased Skid as l~oad Is N" l)’creans4’d but With No Skid at Anyt Loand

Advanced Technology for Pyrotechnic Mixtures and Munitions

DTIC Science & Technology

1977-07-01

or at ambient I ,/ BLENDING AND CASTING CURING REMOVING MOLD WAFER MANUFACTURING ? / I / SI ,/ iAUTOMATIC LOADING Figure 1. Plastic Bonded Starter Mix...material (fines) is recycled through the compacting rollers. asshwn The Chilsonator used at EA consisted only of the compaction rollers and the controls ...standardized process controls . Oversize material is pulverized and combined with the undersize material for s" ,regranulation in another batch. 2 ,Both the

Rolamite acceleration sensor

DOEpatents

Abbin, Joseph P.; Briner, Clifton F.; Martin, Samuel B.

1993-01-01

A rolamite acceleration sensor which has a failsafe feature including a housing, a pair of rollers, a tension band wrapped in an S shaped fashion around the rollers, wherein the band has a force-generation cut out and a failsafe cut out or weak portion. The failsafe cut out or weak portion breaks when the sensor is subjected to an excessive acceleration so that the sensor fails in an open circuit (non-conducting) state permanently.

Dynamic and thermal analysis of high speed tapered roller bearings under combined loading

NASA Technical Reports Server (NTRS)

Crecelius, W. J.; Milke, D. R.

1973-01-01

The development of a computer program capable of predicting the thermal and kinetic performance of high-speed tapered roller bearings operating with fluid lubrication under applied axial, radial and moment loading (five degrees of freedom) is detailed. Various methods of applying lubrication can be considered as well as changes in bearing internal geometry which occur as the bearing is brought to operating speeds, loads and temperatures.

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

ERIC Educational Resources Information Center

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,…

Competition After Windrowing or Single-Roller Chopping For Site Preparation in the Southern Piedmont

Treesearch

James H. Miller

1980-01-01

For two years, post-treatment regrowth of herbaceous and woody species was sampled on two adjoining areas in the southern Piedmont where they had been either sheared and piled into windrows or chopped by a single pass of a single-drum roller-chopper. Windrowing yielded 55% less total standing crop of woody trees, shrubs, and vines after 2 years than chopping did. But...

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

PubMed

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

2008-02-12

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 size fractions between 0 and 2000 microm and by calculating the demixing potential. Significant inhomogeneous occurrence of calcium carbonate in the size fractions was demonstrated, depending mostly on the particles sizes of sorbitol but also on the morphological forms of calcium carbonate. The heterogeneous distribution of calcium carbonate was related to the decrease in compactibility of roller compacted granules in comparison to the ungranulated materials. This phenomenon was explained by a mechanism where fracturing of the ribbon during granulation occurred at the weakest interparticulate bonds (the calcium carbonate: calcium carbonate bonds) and consequently exposed the weakest areas of bond formation on the surface of the granules. Accordingly, the non-uniform allocation of the interparticulate attractive forces in a tablet would cause a lowering of the compactibility. Furthermore, the ability of the powder to agglomerate in the roller compactor was demonstrated to be related to the ability of the powder to be compacted into a tablet, thus the most compactable calcium carbonate and the smallest sized sorbitol improved the homogeneity by decreasing the demixing potential.

Distribution and Molecular Characterization of β-Glucans from Hull-Less Barley Bran, Shorts and Flour

PubMed Central

Zheng, Xueling; Li, Limin; Wang, Qi

2011-01-01

Six hull-less barley cultivars widely grown in China were roller-milled to produce bran, shorts and flour fractions. The distribution and molecular characteristics of β-glucans from the three roller-milled fractions were investigated. The β-glucan contents in the six hull-less barley cultivars varied from 4.96% to 7.62%. For all the six cultivars, the shorts fraction contained the highest concentration of β-glucan (8.12–13.01%), followed by bran (6.15–7.58%) and flour (2.48–2.95%). Crude β-glucans were prepared from the three roller-milled fractions using aqueous sodium carbonate (pH 10). These preparations contained 45.38–71.41% β-glucan, 10.81–17.26% arabinoxylan, 2.6–9.6% protein, 2.7–9.0% starch, and 5.23–9.68% ash. Purification using α-amylase and β-xylanase in combination with pH adjustment and dialysis produced high purity β-glucan preparations (91–95%). The molecular weight (Mw) of β-glucan preparations from roller-milled fractions ranged from 117,600 to 852,400 g/mol. β-Glucan from flour had higher Mw than those from shorts and bran within the same cultivar, and β-glucan preparations from bran had the lowest Mw. PMID:21673907

An improved filter elution and cell culture assay procedure for evaluating public groundwater systems for culturable enteroviruses.

PubMed

Dahling, Daniel R

2002-01-01

Large-scale virus studies of groundwater systems require practical and sensitive procedures for both sample processing and viral assay. Filter adsorption-elution procedures have traditionally been used to process large-volume water samples for viruses. In this study, five filter elution procedures using cartridge filters were evaluated for their effectiveness in processing samples. Of the five procedures tested, the third method, which incorporated two separate beef extract elutions (one being an overnight filter immersion in beef extract), recovered 95% of seeded poliovirus compared with recoveries of 36 to 70% for the other methods. For viral enumeration, an expanded roller bottle quantal assay was evaluated using seeded poliovirus. This cytopathic-based method was considerably more sensitive than the standard plaque assay method. The roller bottle system was more economical than the plaque assay for the evaluation of comparable samples. Using roller bottles required less time and manipulation than the plaque procedure and greatly facilitated the examination of large numbers of samples. The combination of the improved filter elution procedure and the roller bottle assay for viral analysis makes large-scale virus studies of groundwater systems practical. This procedure was subsequently field tested during a groundwater study in which large-volume samples (exceeding 800 L) were processed through the filters.

The dynamic analysis of drum roll lathe for machining of rollers

NASA Astrophysics Data System (ADS)

Qiao, Zheng; Wu, Dongxu; Wang, Bo; Li, Guo; Wang, Huiming; Ding, Fei

2014-08-01

An ultra-precision machine tool for machining of the roller has been designed and assembled, and due to the obvious impact which dynamic characteristic of machine tool has on the quality of microstructures on the roller surface, the dynamic characteristic of the existing machine tool is analyzed in this paper, so is the influence of circumstance that a large scale and slender roller is fixed in the machine on dynamic characteristic of the machine tool. At first, finite element model of the machine tool is built and simplified, and based on that, the paper carries on with the finite element mode analysis and gets the natural frequency and shaking type of four steps of the machine tool. According to the above model analysis results, the weak stiffness systems of machine tool can be further improved and the reasonable bandwidth of control system of the machine tool can be designed. In the end, considering the shock which is caused by Z axis as a result of fast positioning frequently to feeding system and cutting tool, transient analysis is conducted by means of ANSYS analysis in this paper. Based on the results of transient analysis, the vibration regularity of key components of machine tool and its impact on cutting process are explored respectively.

Isocyanate Exposure Below Analytical Detection When a Paint Brush and Roller Are Used to Apply Moisture-Cure Polyurethane Paint.

PubMed

Reeb-Whitaker, Carolyn K; Schoonover, Todd M

2016-05-01

Isocyanate exposure is known to be hazardous when polyurethane paints are applied with a spray gun, but less is known of exposure when paint is applied with a paint brush and roller. Concentrations of 1,6-hexamethylene diisocyanate (HDI) monomer and three HDI polymers were assessed when two moisture-cure polyurethane paints containing 31-35% isocyanates were applied with a paint roller and brush. Short-term 15-min samples were taken during paint application in an indoor test environment with no ventilation (n= 12); in an outdoor test environment (n= 11); and in an outdoor in-situ assessment (n= 22). The outdoor in-situ assessment involved the painting of a bus shelter and light poles at a public transit station over two night shifts. All isocyanate samples were below analytical detection. The analytical limits of detection for HDI monomer, HDI biuret, HDI isocyanurate, and HDI uretdione were 0.005, 0.84, 0.87, and 0.88 µg, respectively. The finding that isocyanate concentrations were below detection is attributed to the use of paint roller and brush which minimize paint aerosolization and the paint formulation itself which contained <1% of volatile HDI monomer. © The Author 2016. Published by Oxford University Press on behalf of the British Occupational Hygiene Society.

A numerical study of the laminar necklace vortex system and its effect on the wake for a circular cylinder

NASA Astrophysics Data System (ADS)

Kirkil, Gokhan; Constantinescu, George

2014-11-01

Large Eddy Simulation is used to investigate the structure of the laminar horseshoe vortex (HV) system and the dynamics of the necklace vortices as they fold around the base of a circular cylinder mounted on the flat bed of an open channel for Reynolds numbers defined with the cylinder diameter, D, smaller than 4,460. The study concentrates on the analysis of the structure of the HV system in the periodic breakaway sub-regime which is characterized by the formation of three main necklace vortices. For the relatively shallow flow conditions considered in this study (H/D 1, H is the channel depth), at times, the disturbances induced by the legs of the necklace vortices do not allow the SSLs on the two sides of the cylinder to interact in a way that allows the vorticity redistribution mechanism to lead to the formation of a new wake roller. As a result, the shedding of large scale rollers in the turbulent wake is suppressed for relatively large periods of time. Simulation results show that the wake structure changes randomly between time intervals when large-scale rollers are forming and are convected in the wake (von Karman regime), and time intervals when the rollers do not form.

Optimization of Friction and Wear Properties of Electroless Ni-P Coatings Under Lubrication Using Grey Fuzzy Logic

NASA Astrophysics Data System (ADS)

Mukhopadhyay, Arkadeb; Duari, Santanu; Barman, Tapan Kumar; Sahoo, Prasanta

2017-10-01

The present study aims to evaluate the friction and wear behaviour of electroless Ni-P coatings sliding against hardened chromium coated steel under lubrication. Tribological tests are carried out on a block-on-roller configuration multi tribotester. The effect of variation of applied normal load, rotation speed of the counterface roller and test duration on the coefficient of friction and wear depth is analyzed using Taguchi's robust design philosophy and design of experiments. Optimal setting of the tribo-testing parameters is evaluated using a hybrid grey fuzzy reasoning analysis in a quest to achieve optimal tribological performance of the coatings under lubrication. Analysis of variance reveals the highest contribution by applied normal load in controlling the tribological behaviour under lubrication. Whereas the interaction effect of load and time is also seen to cast a significant effect. Surface morphology studies reveal a typical nodular structure of the deposits. The coatings are seen to be amorphous in its as-deposited condition which becomes crystalline on heat treatment. Further, the synergistic effects of test parameters, microstructure of the coatings, lubrication, etc. on the tribological behaviour are assessed.

Defense Science Board Task Force on Mobility

DTIC Science & Technology

2005-09-01

stock or nonpalletized loads without removing roller conveyors from the deck, but by using flip-over roller trays like those on the ... on such narrow runways, the C-17 can turn around by using its backing capability to perform a three-point star turn. 24. Most of the material presented...Standard Form 298 (Rev. 2-89) (EG) Prescribed by ANSI Std. 230.18 Designed using Perform Pro, WHSIDIOR, Oct 94 OFFICE OF THE SECRETARY

Methods to improve efficiency of production technology of the innovative composite cementing materials

NASA Astrophysics Data System (ADS)

Babaevsky, A. N.; Romanovich, A. A.; Glagolev, E. S.

2018-03-01

The article describes the energy-saving technology and equipment for production of composite binding material with up to a 50% reduction in energy consumption of the process due to a synergistic effect in mechanical activation of the raw mix where a clinker component is substituted with an active mineral supplement. The impact of the gap between the rollers on the final performance of the press roller mill was studied.

Running on Empty: Schools Cope with the Roller-Coaster World of Cost Run-Ups and Budget Let-Downs

ERIC Educational Resources Information Center

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…

Rolamite acceleration sensor

DOEpatents

Abbin, J.P.; Briner, C.F.; Martin, S.B.

1993-12-21

A rolamite acceleration sensor is described which has a failsafe feature including a housing, a pair of rollers, a tension band wrapped in an S shaped fashion around the rollers, wherein the band has a force-generation cut out and a failsafe cut out or weak portion. The failsafe cut out or weak portion breaks when the sensor is subjected to an excessive acceleration so that the sensor fails in an open circuit (non-conducting) state permanently. 6 figures.

A roller-like bird (Coracii) from the Early Eocene of Denmark.

PubMed

Bourdon, Estelle; Kristoffersen, Anette V; Bonde, Niels

2016-09-27

The fossil record of crown group birds (Neornithes) prior to the Cretaceous-Paleogene boundary is scarce and fragmentary. Early Cenozoic bird fossils are more abundant, but are typically disarticulated and/or flattened. Here we report the oldest roller (Coracii), Septencoracias morsensis gen. et sp. nov. (Primobucconidae), based on a new specimen from the Early Eocene (about 54 million years ago) Fur Formation of Denmark. The new fossil is a nearly complete, three-dimensionally preserved and articulated skeleton. It lies at the lower end of the size range for extant rollers. Salient diagnostic features of Septencoracias relative to other Coracii include the proportionally larger skull and the small, ovoid and dorsally positioned narial openings. Our discovery adds to the evidence that the Coracii had a widespread northern hemisphere distribution in the Eocene. Septencoracias is the oldest substantial record of the Picocoraciae and provides a reliable calibration point for molecular phylogenetic studies.

A roller-like bird (Coracii) from the Early Eocene of Denmark

PubMed Central

Bourdon, Estelle; Kristoffersen, Anette V.; Bonde, Niels

2016-01-01

The fossil record of crown group birds (Neornithes) prior to the Cretaceous-Paleogene boundary is scarce and fragmentary. Early Cenozoic bird fossils are more abundant, but are typically disarticulated and/or flattened. Here we report the oldest roller (Coracii), Septencoracias morsensis gen. et sp. nov. (Primobucconidae), based on a new specimen from the Early Eocene (about 54 million years ago) Fur Formation of Denmark. The new fossil is a nearly complete, three-dimensionally preserved and articulated skeleton. It lies at the lower end of the size range for extant rollers. Salient diagnostic features of Septencoracias relative to other Coracii include the proportionally larger skull and the small, ovoid and dorsally positioned narial openings. Our discovery adds to the evidence that the Coracii had a widespread northern hemisphere distribution in the Eocene. Septencoracias is the oldest substantial record of the Picocoraciae and provides a reliable calibration point for molecular phylogenetic studies. PMID:27670387

Study on the Effect of Steel Wheel and Ground on Single Steel Vibratory Roller

NASA Astrophysics Data System (ADS)

Li, Jiabo; You, Guanghui; Qiao, Jiabin; Ye, Min; Guo, Jin; Zhang, Hongyang

2018-03-01

In the compacting operation of single drum vibratory roller, the forces acting on the foundation of drum include the weight of the drum, the weight of the frame, the exciting force and so on. Based on the theoretical study of ground mechanics, this paper analyzes and calculates the forces acting on the steel wheel and the ground, and obtains the distribution of the laminar stress in the ground when the working plane vibrates. Derive the formula of dynamic compressive stress and static compressive stress in the foundation during vibration compaction. Through the compaction test of the soil trough of 20T single drum roller, the compressive stress data of the soil hydraulic field are obtained. The data of the dynamic compressive stress and the static compressive stress of each layer during the third compaction are obtained, and the theoretical research is verified.

Visualization in mechanics: the dynamics of an unbalanced roller

NASA Astrophysics Data System (ADS)

Cumber, Peter S.

2017-04-01

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 user interface for its numerical solution in MATLAB. This allows a student's focus to be on the influence of different parameters on the system dynamics. The simulation tool can be used as a dynamics demonstrator in a lecture or as an educational tool driven by the imagination of the student. By way of demonstration the simulation tool has been applied to a range of roller-pivot arm configurations. In addition, approximations to the equations of motion are explored and a second-order model is shown to be accurate for a limited range of parameters.

Friction behavior of a multi-interface system and improved performance by AlMgB 14–TiB 2–C and diamond-like-carbon coatings

DOE PAGES

Qu, Jun; Blau, Peter J.; Higdon, Clifton; ...

2016-03-29

We investigated friction behavior of a bearing system with two interfaces involved: a roller component experiencing rolling–sliding interaction against twin cylinders under point contacts while simultaneously undergoing pure sliding interaction against a socket under a conformal contact. Lubrication modeling predicted a strong correlation between the roller's rolling condition and the system's friction behavior. Experimental observations first validated the analytical predictions using steel and iron components. Diamond-like-carbon (DLC) coating and AlMgB 14–TiB 2 coating with a carbon topcoat (BAMC) were then applied to the roller and twin cylinders, respectively. In conclusion, testing and analysis results suggest that the coatings effectively decreasedmore » the slip ratio for the roller–cylinder contact and the sliding friction at both bearing interfaces and, as a result, significantly reduced the system frictional torque.« less

In-line pressure within a HOTLINE® Fluid Warmer, under various flow conditions.

PubMed

Higashi, Midoriko; Yamaura, Ken; Matsubara, Yukie; Fukudome, Takuya; Hoka, Sumio

2015-04-01

Roller pump infusion devices are widely used for rapid infusion, and may be combined with separate warming devices. There may be instances however, where the pressures generated by the roller pump may not be compatible with the warming device. We assessed a commonly used roller pump in combination with a HOTLINE® Fluid Warmer, and found that it could generate pressures exceeding the HOTLINE® manufacturers specifications. This was of concern because the HOTLINE® manufacturer guideline states that not for use with pressure devices generating over 300 mmHg. Pressure greater than 300 mmHg may compromise the integrity of the HOTLINE® Fluid Warming Set. The aim of this study was to compare in-line pressure within a HOTLINE® Fluid Warmer at different infusion rates of a roller pump using various sizes of intravenous cannulae. The rapid infusion system comprised a 500 mL-normal saline bag, roller pump type infusion device, HOTLINE® Fluid Warmer (blood and fluid warmer system), and six different sizes of intravenous cannulae. In-line pressure was measured proximal to the HOTLINE® (pre-warmer) and proximal to the cannula (post-warmer), at flow rate of 50-160 mL/min. The in-line pressures increased significantly with increasing flow rate. The pre-warmer pressures exceeded 300 mmHg when the flow rate was ≥120 mL/min with 20-gauge, 48 mm length cannula, 130 with 20-gauge, 25 mm cannula, and 160 mL/min with 18-gauge, 48 mm cannula. However, they were <300 mmHg at any flow rates with 18-gauge, 30 mm cannula and 16-gauge cannulae. The post-warmer pressures exceeded 300 mmHg at the flow rate of 140 mL/min with 20-gauge, 48 mm cannula, and 160 mL/min with 20-gauge, 25 mm cannula, while they were <300 mmHg at any flow rates with 18 and 16-gauge cannulae. The in-line pressure within a HOTLINE® could exceed 300 mmHg, depending on the flow rate and size and length of cannula. It is important to pay attention to the size and length of cannulae and flow rate to keep the maximum in-line pressure<300 mmHg when a roller pump type infusion device is used.

Experiences with Interactive Multi-touch Tables

NASA Astrophysics Data System (ADS)

Fikkert, Wim; Hakvoort, Michiel; van der Vet, Paul; Nijholt, Anton

Interactive multi-touch tables can be a powerful means of communication for collaborative work as well as an engaging environment for competition. Through enticing gameplay we have evaluated user experience on competitive gameplay, collaborative work and musical expression. In addition, we report on our extensive experiences with two types of interactive multi-touch tables and we introduce a software framework that abstracts from their technical differences.

A gravity exercise system. [for muscle conditioning during manned space flight

NASA Technical Reports Server (NTRS)

Brandt, W. E.; Clark, A. L.

1973-01-01

An effective method for muscle conditioning during weightlessness flight is derived from isometric exercise. The basic principle of gravity exercise is to periodically displace the human body upon reactionless rollers so that spacial equilibrium can only be maintained by the proper tension and relaxation of the body's muscles. A rotating platform mounted upon two degrees of freedom rollers provides such a condition of gravitational reaction stress throughout each of its 360 deg rotation.

Pin and roller attachment system for ceramic blades

DOEpatents

Shaffer, James E.

1995-01-01

In a turbine, a plurality of blades are attached to a turbine wheel by way of a plurality of joints which form a rolling contact between the blades and the turbine wheel. Each joint includes a pin and a pair of rollers to provide rolling contact between the pin and an adjacent pair of blades. Because of this rolling contact, high stress scuffing between the blades and the turbine wheel reduced, thereby inhibiting catastrophic failure of the blade joints.

TOP 04-1-010 Effectiveness Testing of Mechanical Clearing Systems - Roller Systems Operating in a Straight Path

DTIC Science & Technology

2017-12-04

36 APPENDIX A. TEST LANE DESIGN AND CONFUGURATION ............. A-1 B. EXAMPLE CHECKLISTS AND DATA SHEETS ............. B-1 C. ROLLER...categories and configurations, burial depths, etc.) allow for direct comparison of systems, from legacy systems (fielded) to new designs not having...effectiveness assessment of the SUT, but may indicate shortfall or design deficiency of the SUT in the integration to a specific PM, or a safety flag

Advanced Power Transmission Technology, Proceedings of a Symposium Held at NASA Lewis Research Center, Cleveland, Ohio on June 9-11, 1981.

DTIC Science & Technology

1983-01-01

experiments of (aggerneier ( rvf . 44). The observed, pronounced reduction in the available traction coefficient with just a few degrees of misalinement...Co., 1979. (AFAPL-TR-79-2007, AD-A069440.) 6. Crecelius, W. J.; and Milke , D. R,: Dynamic and Thermal Analysis of High Speed Tapered Roller Bearings...appearance of milk . When the narrow band of intense light crossed the fan of white oil, a bright line of it was illuminated so that it could be L GRIT BEAM

Creating a business backbone. A first person recount of the planning process involved in laying the foundation of a successful rehabilitation clinic.

PubMed

Babb, Robert W

2007-01-01

Opening your own outpatient therapy center will likely seem an insurmountable task at times. Broken down into the stages of mission establishment, planning and goal setting, establishing financial viability, choosing equipment, promoting your product, and, finally, hiring staff, this task will become less onerous. Remember, it is your practice. True to your vision, and just like high school, be prepared for an emotional roller-coaster ride. Done correctly, this experience will be just as thrilling and ultimately much more gratifying.

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

PubMed

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. © 2014. Published by The Company of Biologists Ltd.

Rheological, physico-sensory, nutritional and storage characteristics of bread enriched with roller milled fractions of black gram (Phaseolus mungo L.).

PubMed

Indrani, D; Sakhare, Suresh D; Milind; Inamdar, Aashitosh A

2015-08-01

Black gram grains were fractionated using roller flour mill. Effect of combination of additives (CA) namely dry gluten powder, sodium stearoyl-2-lactylate, fungal α-amylase on the rheological and bread making characteristics of wheat flour partly replaced with roller milled fractions of black gram was studied. With increase in the addition of straight run flour (SRF), protein rich fraction (PRF), protein and fiber rich fraction (P&FRF) from 0 to 20 %, fiber rich fraction, FRF (0-15 %), the farinograph water absorption increased and dough stability decreased; amylograph pasting temperature increased and peak viscosity decreased; bread volume decreased and crumb firmness value increased indicating adverse effect of these fractions on the rheological and bread making characteristics of wheat flour. Sensory evaluation showed that breads were acceptable only up to the level of 15 % for SRF, PRF & P&FRF and 10 % for FRF. However, when CA containing dry gluten powder, sodium stearoyl-2-lactylate and fungal α-amylase was incorporated the overall quality of the products improved. Use of these fractions increased the protein and fiber contents of bread by 1.24-1.66 and 1.48-3.79 times respectively. The results showed that possibility of utilising roller milled black gram fractions along with CA to improve the taste, texture and nutritional quality of bread.

The three-dimensional evolution of a plane mixing layer. Part 1: The Kelvin-Helmholtz roll-up

NASA Technical Reports Server (NTRS)

Rogers, Michael M.; Moser, Robert D.

1991-01-01

The Kelvin Helmholtz roll up of three dimensional, temporally evolving, plane mixing layers were simulated numerically. All simulations were begun from a few low wavenumber disturbances, usually derived from linear stability theory, in addition to the mean velocity profile. The spanwise disturbance wavelength was taken to be less than or equal to the streamwise wavelength associated with the Kelvin Helmholtz roll up. A standard set of clean structures develop in most of the simulations. The spanwise vorticity rolls up into a corrugated spanwise roller, with vortex stretching creating strong spanwise vorticity in a cup shaped region at the vends of the roller. Predominantly streamwise rib vortices develop in the braid region between the rollers. For sufficiently strong initial three dimensional disturbances, these ribs collapse into compact axisymmetric vortices. The rib vortex lines connect to neighboring ribs and are kinked in the opposite direction of the roller vortex lines. Because of this, these two sets of vortex lines remain distinct. For certain initial conditions, persistent ribs do not develop. In such cases the development of significant three dimensionality is delayed. When the initial three dimensional disturbance energy is about equal to, or less than, the two dimensional fundamental disturbance energy, the evolution of the three dimensional disturbance is nearly linear (with respect to the mean and the two dimensional disturbances), at least until the first Kelvin Helmholtz roll up is completed.

Biomechanical pole and leg characteristics during uphill diagonal roller skiing.

PubMed

Lindinger, Stefan Josef; Göpfert, Caroline; Stöggl, Thomas; Müller, Erich; Holmberg, Hans-Christer

2009-11-01

Diagonal skiing as a major classical technique has hardly been investigated over the last two decades, although technique and racing velocities have developed substantially. The aims of the present study were to 1) analyse pole and leg kinetics and kinematics during submaximal uphill diagonal roller skiing and 2) identify biomechanical factors related to performance. Twelve elite skiers performed a time to exhaustion (performance) test on a treadmill. Joint kinematics and pole/plantar forces were recorded separately during diagonal roller skiing (9 degrees; 11 km/h). Performance was correlated to cycle length (r = 0.77; P < 0.05), relative leg swing (r = 0.71), and gliding time (r = 0.74), hip flexion range of motion (ROM) during swing (r = 0.73) and knee extension ROM during gliding (r = 0.71). Push-off demonstrated performance correlations for impulse of leg force (r = 0.84), relative duration (r= -0.76) and knee flexion (r = 0.73) and extension ROM (r = 0.74). Relative time to peak pole force was associated with performance (r = 0.73). In summary, diagonal roller skiing performance was linked to 1) longer cycle length, 2) greater impulse of force during a shorter push-off with larger flexion/extension ROMs in leg joints, 3) longer leg swing, and 4) later peak pole force, demonstrating the major key characteristics to be emphasised in training.

Drilling plastic formations using highly polished PDC cutters

DOE Office of Scientific and Technical Information (OSTI.GOV)

Smith, R.H.; Lund, J.B.; Anderson, M.

1995-12-31

Highly plastic and over-pressured formations are troublesome for both roller cone and PDC bits. Thus far, attempts to increase penetration rates in these formations have centered around re-designing the bit or modifying the cutting structure. These efforts have produced only moderate improvements. This paper presents both laboratory and field data to illustrate the benefits of applying a mirror polished surface to the face of PDC cutters in drilling stressed formations. These cutters are similar to traditional PDC cutters, with the exception of the reflective mirror finish, applied to the diamond table surfaces prior to their installation in the bit. Resultsmore » of tests conducted in a single point cutter apparatus and a full-scale drilling simulator will be presented and discussed. Field results will be presented that demonstrate the effectiveness of polished cutters, in both water and oil-based muds. Increases in penetration rates of 300-400% have been observed in the Wilcox formation and other highly pressured shales. Typically, the beneficial effects of polished cutters have been realized at depths greater than 7000 ft, and with mud weights exceeding 12 ppg.« less

187Re - 232Th - 238U nuclear geochronometry: constraining magmatism in East-Antarctica and the break-up of Gondwana

NASA Astrophysics Data System (ADS)

Roller, Goetz

2017-04-01

187Re - 232Th - 238U nuclear geochronometry is a new dating method for astronomy, earth and planetary sciences [1-4]. Nucleogeochronometric Rhenium-Osmium two-point-isochron (TPI) ages are calculated using a nuclear geochronometer as one data point in a two-point-isochron diagram [5-7]. The IVREA chronometer, for example, is one of five terrestrial nuclear geochronometers identified so far [8]. Here, it is used to constrain the magmatism of the Ferrar flood basalt province, which has been related to continental rifting and the break-up of Gondwana in the Jurassic.TPI ages for seven (basaltic) andesite whole rock samples from the Prince Albert Mountains (Victoria Land, Antarctica) are calculated. An isochron age of 172 ± 5 Ma (187Os/188Osi = 0.194 ± 0.023) has previously been published for these rocks [9]. Initial TPI 187Os/188Osi ratios show only minor scatter between 187Os/188Osi = 0.2149 ± 0.0064 and 187Os/188Osi = 0.22231 ± 0.00080, in agreement with the enigmatic, suprachondritic 187Os/188Osi = 0.194 ± 0.023 from the isochron [9]. TPI ages for the Mount Joyce samples range from 125.4 ± 9.9 Ma to 139 ± 17 Ma and thus constrain the youngest magmatic event(s) in the Transantarctic Mountains. For the Thumb Point basalt, a TPI age of 219 ± 81 Ma is calculated. Despite of its large uncertainty, the age itself is in agreement with the Triassic 224 Ma and 240 Ma events reported from North Patagonia [10]. The TPI age of 186.1 ± 8.1 Ma from the Ricker Hill basalt can be clearly distinguished from the Mount Murray TPI age of 158 ± 14 Ma, while at Brimstone Peak two TPI age groups of 155 ± 14 Ma and 175.3 ± 3.1 Ma are observed. From this it may be concluded that the seven TPI ages indicate episodic magmatic activity in East-Antarctica between 125 Ma and 219 Ma, leading to the break-up of Gondwana. This picture is consistent with the geochronology of the Antarctic Peninsula, Patagonia, the Karoo and the Ferrar mafic rocks [10]. Thus, besides constraining planetary crust formation in general, nuclear geochronometry may also become an additional powerful tool in constraining not only magmatic activity in Antarctica but also the assembly and break-up of Pangaea and subsequently Gondwana from the Carboniferous on, as revealed by means of nuclear geochronometry for the ultramafic dykes within the Balmuccia peridotite (Ivrea Zone, NW Italy). [1] Roller (2015), Goldschmidt Conf. Abstr. 25, 2672. [2] Roller (2016), Goldschmidt Conf. Abstr. 26, 2642. [3] Roller (2015), Geophys Res. Abstr. 17, 2399. [4] Roller (2016), Geophys Res. Abstr. 18, 33. [5] Roller (2016), JPS Conf. Proc., Nuclei in the Cosmos (NIC XIV), Niigata, Japan, subm. (NICXIV-001); NICXIV Abstr. #1570244284. [6] Roller (2016), JPS Conf. Proc., Nuclei in the Cosmos (NIC XIV), Niigata, Japan, subm. (NICXIV-002); NICXIV Abstr. #1570244285). [7] Roller (2016), JPS Conf. Proc., Nuclei in the Cosmos (NIC XIV), Niigata, Japan, subm. (NICXIV-003); NICXIV Abstr. #1570244281. [8] Roller (2015), Geophys Res. Abstr. 17, 17. [9] Molzahn et al. (1996), Earth Planet. Sci. Lett. 144, 529 - 546. [10] Pankhurst et al. (2000), J. Petrol. 41, 605 - 625.

Pivot tables for mortality analysis, or who needs life tables anyway?

PubMed

Wesley, David; Cox, Hugh F

2007-01-01

Actuarial life-table analysis has long been used by life insurance medical directors for mortality abstraction from clinical studies. Ironically, today's life actuary instead uses pivot tables to analyze mortality. Pivot tables (a feature/function in MS Excel) collapse various dimensions of data that were previously arranged in an "experience study" format. Summary statistics such as actual deaths, actual and expected mortality (usually measured in dollars), and calculated results such as actual to expected ratios, are then displayed in a 2-dimensional grid. The same analytic process, excluding the dollar focus, can be used for clinical mortality studies. For raw survival data, especially large datasets, this combination of experience study data and pivot tables has clear advantages over life-table analysis in both accuracy and flexibility. Using the SEER breast cancer data, we compare the results of life-table analysis and pivot-table analysis.

The influence of increased distal loading on metabolic cost, efficiency, and kinematics of roller ski skating.

PubMed

Bolger, Conor M; Bessone, Veronica; Federolf, Peter; Ettema, Gertjan; Sandbakk, Øyvind

2018-01-01

The purpose of the present study was to examine the influence of increased loading of the roller ski on metabolic cost, gross efficiency, and kinematics of roller ski skating in steep and moderate terrain, while employing two incline-specific techniques. Ten nationally ranked male cross-country skiers were subjected to four 7-minute submaximal intervals, with 0, 0.5, 1.0, and 1.5 kg added beneath the roller-ski in a randomized order. This was done on two separate days, with the G2 skating at 12% incline and 7 km/h speed and G3 skating at 5% incline and 14 km/h speed, respectively. At 12% incline, there was a significant increase in metabolic rate and a decrease in gross efficiency with added weight (P<0.001 and P = 0.002). At 5% incline, no change in metabolic rate or gross efficiency was found (P = 0.89 and P = 0.11). Rating of perceived exertion (RPE) increased gradually with added weight at both inclines (P>0.05). No changes in cycle characteristics were observed between the different ski loadings at either incline, although the lateral and vertical displacements of the foot/skis were slightly altered at 12% incline with added weight. In conclusion, the present study demonstrates that increased loading of the ski increases the metabolic cost and reduces gross efficiency during steep uphill roller skiing in G2 skating, whereas no significant effect was revealed when skating on relatively flat terrain in G3. Cycle characteristics remained unchanged across conditions at both inclines, whereas small adjustments in the displacement of the foot coincided with the efficiency changes in uphill terrain. The increased RPE values with added ski-weight at both inclines indicates that other factors than those measured here could have influenced effort and/or fatigue when lifting a heavier ski.

The development of 8 inch roll-to-plate nanoimprint lithography (8-R2P-NIL) system

NASA Astrophysics Data System (ADS)

Lee, Lai Seng; Mohamed, Khairudin; Ooi, Su Guan

2017-07-01

Growth in semiconductor and integrated circuit industry was observed in the past decennium of years for industrial technology which followed Moore's law. The line width of nanostructure to be exposed was influenced by the essential technology of photolithography. Thus, it is crucial to have a low cost and high throughput manufacturing process for nanostructures. Nanoimprint Lithography technique invented by Stephen Y. Chou was considered as major nanolithography process to be used in future integrated circuit and integrated optics. The drawbacks of high imprint pressure, high imprint temperature, air bubbles formation, resist sticking to mold and low throughput of thermal nanoimprint lithography on silicon wafer have yet to be solved. Thus, the objectives of this work is to develop a high throughput, low imprint force, room temperature UV assisted 8 inch roll to plate nanoimprint lithography system capable of imprinting nanostructures on 200 mm silicon wafer using roller imprint with flexible mold. A piece of resist spin coated silicon wafer was placed onto vacuum chuck drives forward by a stepper motor. A quartz roller wrapped with a piece of transparent flexible mold was used as imprint roller. The imprinted nanostructures were cured by 10 W, 365 nm UV LED which situated inside the quartz roller. Heat generated by UV LED was dissipated by micro heat pipe. The flexible mold detaches from imprinted nanostructures in a 'line peeling' pattern and imprint pressure was measured by ultra-thin force sensors. This system has imprinting speed capability ranging from 0.19 mm/s to 5.65 mm/s, equivalent to imprinting capability of 3 to 20 pieces of 8 inch wafers per hour. Speed synchronization between imprint roller and vacuum chuck was achieved by controlling pulse rate supplied to stepper motor which drive the vacuum chuck. The speed different ranging from 2 nm/s to 98 nm/s is achievable. Vacuum chuck height was controlled by stepper motor with displacement of 5 nm/step.

Characterization of the High-Speed-Stage Bearing Skidding of Wind Turbine Gearboxes Induced by Dynamic Electricity Grid Events

DOE Office of Scientific and Technical Information (OSTI.GOV)

Helsen, Jan; Guillaume, Patrick; Guo, Yi

Bearing behavior is an important factor for wind turbine drivetrain reliability. Extreme loads and dynamic excitations pose challenges to the bearing design and therefore its performance. Excessive skidding of the bearing rollers should be avoided because it can cause scuffing failures. Excitations coming from wind and the electricity grid can subject the drivetrain to fluctuating torque and nontorque loads. Wind-induced excitations have been investigated predominantly in literature. However, modern wind turbines are subjected more and more to grid-induced loads because of stricter electricity grid regulations. For example, during fault-ride-through events, turbines are required to stay connected for a longer periodmore » of time during the grid failure. This work investigates the influence of electrically induced excitations on the skidding behaviour of the tapered roller bearings on the high-speed stage of a wind turbine gearbox. This skidding behaviour during dynamic events is described as a potential bearing failure initiator by many researchers; however, only limited full-scale dynamic testing is documented. Therefore, a dedicated gridloss-type event is defined in the paper and conducted in a dynamometer test on a full-scale wind turbine nacelle. During the event, a complete electricity grid failure is simulated while the turbine is at rated speed and predefined torque levels. Particular focus is on the characterization of the high-speed shaft tapered roller bearing slip behavior. Strain-gauge bridges in grooves along the circumference of the outer ring are used to characterize the bearing load zone in detail. It is shown that during the torque reversals of the transient event, roller slip can be induced. This indicates the potential of the applied load case to go beyond the preload of the tapered roller bearing. Furthermore, the relation between the applied torque and skidding level is studied.« less

Characterization of the High-Speed-Stage Bearing Skidding of Wind Turbine Gearboxes Induced by Dynamic Electricity Grid Events: Preprint

DOE Office of Scientific and Technical Information (OSTI.GOV)

Helsen, Jan; Guillaume, Patrick; Guo, Yi

Bearing behavior is an important factor for wind turbine drivetrain reliability. Extreme loads and dynamic excitations pose challenges to the bearing design and therefore its performance. Excessive skidding of the bearing rollers should be avoided because it can cause scuffing failures. Excitations coming from wind and the electricity grid can subject the drivetrain to fluctuating torque and nontorque loads. Wind-induced excitations have been investigated predominantly in literature. However, modern wind turbines are subjected more and more to grid-induced loads because of stricter electricity grid regulations. For example, during fault-ride-through events, turbines are required to stay connected for a longer periodmore » of time during the grid failure. This work investigates the influence of electrically induced excitations on the skidding behaviour of the tapered roller bearings on the high-speed stage of a wind turbine gearbox. This skidding behaviour during dynamic events is described as a potential bearing failure initiator by many researchers; however, only limited full-scale dynamic testing is documented. Therefore, a dedicated gridloss-type event is defined in the paper and conducted in a dynamometer test on a full-scale wind turbine nacelle. During the event, a complete electricity grid failure is simulated while the turbine is at rated speed and predefined torque levels. Particular focus is on the characterization of the high-speed shaft tapered roller bearing slip behavior. Strain-gauge bridges in grooves along the circumference of the outer ring are used to characterize the bearing load zone in detail. It is shown that during the torque reversals of the transient event, roller slip can be induced. This indicates the potential of the applied load case to go beyond the preload of the tapered roller bearing. Furthermore, the relation between the applied torque and skidding level is studied.« less

Comparative performance of contact plates, electrostatic wipes, swabs and a novel sampling device for the detection of Staphylococcus aureus on environmental surfaces.

PubMed

Lutz, J K; Crawford, J; Hoet, A E; Wilkins, J R; Lee, J

2013-07-01

To evaluate the performance of four sampling methods [contact plates, electrostatic wipes (wipe), swabs and a novel roller sampler] for recovery of Staphylococcus aureus from a stainless steel surface. Stainless steel test plates were inoculated with Staph. aureus, dried for 24 h and sampled using each of the four methods. Samples were either incubated directly (roller, contact plate) or processed using elution and membrane filtration (swab, wipe). Performance was assessed by calculating the apparent sampling efficiency (ASE), analytical sensitivity (Sn) and percentage of replications with positive growth. The wipe demonstrated the best performance across all inoculating concentrations (ASE(48 h) = 18%; Sn(48 h) = 7 CFU per 100 cm(2)). The swab performed well when corrected for area actually sampled (ASE(48 h) = 24%; Sn(48 h) = 76 CFU per 100 cm(2)). Of the contact-based methods, the newly developed roller sampler outperformed the contact plate (roller: ASE(48 h) = 10%; Sn(48 h) = 17 CFU per 100 cm(2); contact plate: ASE(48 h) = 0·04%; Sn(48 h) = 1412 CFU per 100 cm(2)); both contact samplers performed better at higher inoculating concentrations (6E3 CFU per 100 cm(2) for the roller and 6E6 CFU per 100 cm(2) for the contact plate). Overall, the electrostatic wipe produced the highest number of replications resulting in positive growth (74%(24 h), 91%(48 h)). This study demonstrates that selection of the sampling method must be carefully considered, given that different methods have varying performance. This is the first study assessing static wipes for sampling and one that uses a more real-world-relevant 24-h drying time. The results help with infection control, and environmental health professionals choose better sampling methodologies. Journal of Applied Microbiology © 2013 The Society for Applied Microbiology.

Optimization of the dressing parameters in cylindrical grinding based on a generalized utility function

NASA Astrophysics Data System (ADS)

Aleksandrova, Irina

2016-01-01

The existing studies, concerning the dressing process, focus on the major influence of the dressing conditions on the grinding response variables. However, the choice of the dressing conditions is often made, based on the experience of the qualified staff or using data from reference books. The optimal dressing parameters, which are only valid for the particular methods and dressing and grinding conditions, are also used. The paper presents a methodology for optimization of the dressing parameters in cylindrical grinding. The generalized utility function has been chosen as an optimization parameter. It is a complex indicator determining the economic, dynamic and manufacturing characteristics of the grinding process. The developed methodology is implemented for the dressing of aluminium oxide grinding wheels by using experimental diamond roller dressers with different grit sizes made of medium- and high-strength synthetic diamonds type ??32 and ??80. To solve the optimization problem, a model of the generalized utility function is created which reflects the complex impact of dressing parameters. The model is built based on the results from the conducted complex study and modeling of the grinding wheel lifetime, cutting ability, production rate and cutting forces during grinding. They are closely related to the dressing conditions (dressing speed ratio, radial in-feed of the diamond roller dresser and dress-out time), the diamond roller dresser grit size/grinding wheel grit size ratio, the type of synthetic diamonds and the direction of dressing. Some dressing parameters are determined for which the generalized utility function has a maximum and which guarantee an optimum combination of the following: the lifetime and cutting ability of the abrasive wheels, the tangential cutting force magnitude and the production rate of the grinding process. The results obtained prove the possibility of control and optimization of grinding by selecting particular dressing parameters.

Development of procedures for calculating stiffness and damping of elastomers in engineering applications, part 7

NASA Technical Reports Server (NTRS)

Rieger, A.; Zorzi, E.

1980-01-01

An elastomer shear damper was designed, tested, and compared with the performance of the T 55 power turbine supported on the production engine roller bearing support. The Viton 70 shear damper was designed so that the elastomer damper could be interchanged with the production T 55 power turbine roller bearing support. The results show that the elastomer sheer dampener permitted stable operation of the power turbine to the maximum operating speed of 16,000 rpm.

Grinding Parts For Automatic Welding

NASA Technical Reports Server (NTRS)

Burley, Richard K.; Hoult, William S.

1989-01-01

Rollers guide grinding tool along prospective welding path. Skatelike fixture holds rotary grinder or file for machining large-diameter rings or ring segments in preparation for welding. Operator grasps handles to push rolling fixture along part. Rollers maintain precise dimensional relationship so grinding wheel cuts precise depth. Fixture-mounted grinder machines surface to quality sufficient for automatic welding; manual welding with attendant variations and distortion not necessary. Developed to enable automatic welding of parts, manual welding of which resulted in weld bead permeated with microscopic fissures.

REACTOR CONTROL SYSTEM

DOEpatents

MacNeill, J.H.; Estabrook, J.Y.

1960-05-10

A reactor control system including a continuous tape passing through a first coolant passageway, over idler rollers, back through another parallel passageway, and over motor-driven rollers is described. Discrete portions of fuel or poison are carried on two opposed active sections of the tape. Driving the tape in forward or reverse directions causes both active sections to be simultaneously inserted or withdrawn uniformly, tending to maintain a more uniform flux within the reactor. The system is particularly useful in mobile reactors, where reduced inertial resistance to control rod movement is important.

Sidewall containment of liquid metal with vertical alternating magnetic fields

DOEpatents

Lari, Robert J.; Praeg, Walter F.; Turner, Larry R.; Battles, James E.; Hull, John R.; Rote, Donald M.

1990-01-01

An apparatus for containing molten metal using a magnet producing vertical alternating magnetic field positioned adjacent the area in which the molten metal is to be confined. This invention can be adapted particularly to the casting of metal between counter-rotating rollers with the vertical alternating magnetic field used to confine the molten metal at the edges of the rollers. Alternately, the vertical alternating magnetic field can be used as a flow regulator in casting molten metal from an opening in a channel.

ACES II Seat Roller Study: Findings of Detrimental Friction under High Windblast or Adverse Flight Conditions

DTIC Science & Technology

2015-08-12

Seat’s legacy "seat roller" (a dry metal wheel on a shaft), when subjected to high loads (such as ejections at high speeds or with an aircraft yaw...Calibrated, Equivalent, True” KIAS = Knots Indicated Airspeed ( aircraft -dependent interpretation of speed , as displayed on gage) KCAS = Knots...the man-seat on the aircraft rail during high- speed ejections. This high friction response – when combined with modern changes to the ejection system

Pin and roller attachment system for ceramic blades

DOEpatents

Shaffer, J.E.

1995-07-25

In a turbine, a plurality of blades are attached to a turbine wheel by way of a plurality of joints which form a rolling contact between the blades and the turbine wheel. Each joint includes a pin and a pair of rollers to provide rolling contact between the pin and an adjacent pair of blades. Because of this rolling contact, high stress scuffing between the blades and the turbine wheel reduced, thereby inhibiting catastrophic failure of the blade joints. 3 figs.

A "roller-wheel" Pt-containing small molecule that outperforms its polymer analogs in organic solar cells

DOE PAGES

He, Wenhan; Wu, Qin; Livshits, Maksim Y.; ...

2016-05-23

A novel Pt-bisacetylide small molecule (Pt-SM) featuring “roller-wheel” geometry was synthesized and characterized. When compared with conventional Pt-containing polymers and small molecules having “dumbbell” shaped structures, Pt-SM displays enhanced crystallinity and intermolecular π–π interactions, as well as favorable panchromatic absorption behaviors. Furthermore, organic solar cells (OSCs) employing Pt-SM achieve power conversion efficiencies (PCEs) up to 5.9%, the highest reported so far for Pt-containing polymers and small molecules.

Geothermal energy conversion system

NASA Astrophysics Data System (ADS)

Goldstein, David

1991-04-01

A generator having a tubular gear made of shape memory alloy in sheet-form floatingly supported for rotation about an axis fixedly spaced from the rotational axis of a roller gear presented. The tubular gear is sequentially deformed by exposure to a geothermal heat source and meshing engagement with the roller gear. Such sequential deformation of the tubular gear is controlled by a temperature differential to induce and sustain rotation of the gears in response to which the heat energy is converted into electrical energy.

A "roller-wheel" Pt-containing small molecule that outperforms its polymer analogs in organic solar cells

DOE Office of Scientific and Technical Information (OSTI.GOV)

He, Wenhan; Wu, Qin; Livshits, Maksim Y.

A novel Pt-bisacetylide small molecule (Pt-SM) featuring “roller-wheel” geometry was synthesized and characterized. When compared with conventional Pt-containing polymers and small molecules having “dumbbell” shaped structures, Pt-SM displays enhanced crystallinity and intermolecular π–π interactions, as well as favorable panchromatic absorption behaviors. Furthermore, organic solar cells (OSCs) employing Pt-SM achieve power conversion efficiencies (PCEs) up to 5.9%, the highest reported so far for Pt-containing polymers and small molecules.

Software Developed for Analyzing High- Speed Rolling-Element Bearings

NASA Technical Reports Server (NTRS)

Fleming, David P.

2005-01-01

COBRA-AHS (Computer Optimized Ball & Roller Bearing Analysis--Advanced High Speed, J.V. Poplawski & Associates, Bethlehem, PA) is used for the design and analysis of rolling element bearings operating at high speeds under complex mechanical and thermal loading. The code estimates bearing fatigue life by calculating three-dimensional subsurface stress fields developed within the bearing raceways. It provides a state-of-the-art interactive design environment for bearing engineers within a single easy-to-use design-analysis package. The code analyzes flexible or rigid shaft systems containing up to five bearings acted upon by radial, thrust, and moment loads in 5 degrees of freedom. Bearing types include high-speed ball, cylindrical roller, and tapered roller bearings. COBRA-AHS is the first major upgrade in 30 years of such commercially available bearing software. The upgrade was developed under a Small Business Innovation Research contract from the NASA Glenn Research Center, and incorporates the results of 30 years of NASA and industry bearing research and technology.

Middle Cerebral Artery Stroke as Amusement Park Injury: Case Report and Review of the Literature.

PubMed

Baumgartle, Abby; Wolfe, Laura; Puri, Vinay; Moeller, Karen; Bertolone, Salvatore; Raj, Ashok

2017-07-31

Strokes as amusement park injuries are rare, but have been reported in the literature. Only about 20 cases of cerebrovascular accidents after amusement park visits have been described. We report a healthy 12-year-old boy who presented with facial droop, slurred speech, and inability to use his right arm after riding roller coasters at a local amusement park. He was evaluated and found to have a left middle cerebral artery (MCA) infarction. The patient was treated with anticoagulants and has recovered with no major residual symptoms. It is likely that his neurological symptoms occurred due to the high head accelerations experienced on the roller coasters, which are more detrimental to children due to immature cervical spine development and muscle strength. Early diagnosis of dissection and stroke results in a favorable prognosis. Providers and parents should be aware of the potential risk of roller coasters and act quickly on neurologic changes in children that have recently been to an amusement park.

Chemical, rheological and bread making characteristics of bran duster flours from roller flourmills.

PubMed

Sakhare, Suresh D; Indrani, D; Inamdar, Aashitosh A; Gaikwad, Shwetha B; Rao, G Venkateswara

2014-10-01

Bran dusters are used in the wheat flour milling process to increase flour extraction rate. Chemical, rheological and bread characteristics of bran duster flours (BDR1, BDR2, BDR3) and straight run flour (SRF) obtained from two commercial roller flour mills were analyzed. Important chemical characteristics such as ash, dry gluten content, sedimentation value, damaged starch and falling number of bran duster flours were determined. Rheological behavior was tested using farinograph and alveograph equipments. The results showed an increase in ash, dry gluten content and Zeleny's sedimentation value for bran duster flours compared to SRF. Rheological characteristics indicated higher farinograph dough development time and stability values for bran duster flours. Alveograph characteristics indicated higher extensibility and lower elasticity values for bran duster flours. Over all quality score of bread for BDR1 from A and B roller flour mills ranged from 73.4 to 74.7, BDR2 (79-81.8), BDR3 (69-70.4) as against SRF (85.4-86.3).

The effect of harvest time, dry matter content and mechanical pretreatments on anaerobic digestion and enzymatic hydrolysis of miscanthus.

PubMed

Frydendal-Nielsen, Susanne; Hjorth, Maibritt; Baby, Sanmohan; Felby, Claus; Jørgensen, Uffe; Gislum, René

2016-10-01

Miscanthus x giganteus was harvested as both green and mature biomass and the dry matter content of the driest harvest was artificially decreased by adding water in two subsamples, giving a total of five dry matter contents. All five biomass types were mechanically pretreated by roller-milling, extrusion or grinding and accumulated methane production and enzymatically-accessible sugars were measured. Accumulated methane production was studied using sigmoid curves that allowed comparison among the treatments of the rate of the methane production and ultimate methane yield. The green biomass gave the highest methane yield and highest levels of enzymatically-accessible cellulose. The driest biomass gave the best effect from extrusion but with the highest energy consumption, whereas roller-milling was most efficient on wet biomass. The addition of water to the last harvest improved the effect of roller-milling and equalled extrusion of the samples in efficiency. Copyright © 2016 Elsevier Ltd. All rights reserved.

Turbulent Premixed Flames in Microgravity

NASA Technical Reports Server (NTRS)

Menon, Suresh

1996-01-01

The experimental cold-flow facility is now full operational and is currently being used to obtain baseline turbulence data in a Couette flow. The baseline turbulence data is necessary to confirm the capability of the chosen device to generate and maintain the required turbulence intensity. Subsequent reacting flow studies will assume that a similar turbulent flow field exists ahead of the premixed flame. Some modifications and refinements had to be made to enable accurate measurements. It consists of two rollers, one (driven by a motor) which drives a continuous belt and four smaller rollers used to set the belt spacing and tension to minimize belt flutter. The entire assemble is enclosed in a structure that has the dimensions to enable future drop tower experiments of the hot facility. All critical dimensions are the same as the original plans except for the pulley ratio which has been changed to enable a wider operating regime in terms of the Reynolds number. With the current setup, Reynolds numbers as low as 100 and as high as 14,000 can be achieved. This is because the in-between belt spacing can be varied from 1 cm to 7.6 cm, and the belt speed can be accurately varied from .15 m/sec to 3.1 m/sec.

Electronic Gaming Machine (EGM) Environments: Market Segments and Risk.

PubMed

Rockloff, Matthew; Moskovsky, Neda; Thorne, Hannah; Browne, Matthew; Bryden, Gabrielle

2017-12-01

This study used a marketing-research paradigm to explore gamblers' attraction to EGMs based on different elements of the environment. A select set of environmental features was sourced from a prior study (Thorne et al. in J Gambl Issues 2016b), and a discrete choice experiment was conducted through an online survey. Using the same dataset first described by Rockloff et al. (EGM Environments that contribute to excess consumption and harm, 2015), a sample of 245 EGM gamblers were sourced from clubs in Victoria, Australia, and 7516 gamblers from an Australian national online survey-panel. Participants' choices amongst sets of hypothetical gambling environments allowed for an estimation of the implied individual-level utilities for each feature (e.g., general sounds, location, etc.). K-means clustering on these utilities identified four unique market segments for EGM gambling, representing four different types of consumers. The segments were named according to their dominant features: Social, Value, High Roller and Internet. We found that the environments orientated towards the Social and Value segments were most conducive to attracting players with relatively few gambling problems, while the High Roller and Internet-focused environments had greater appeal for players with problems and vulnerabilities. This study has generated new insights into the kinds of gambling environments that are most consistent with safe play.

Air Entrainment and Surface Ripples in a Turbulent Ship Hull Boundary Layer

NASA Astrophysics Data System (ADS)

Masnadi, Naeem; Erinin, Martin; Duncan, James H.

2017-11-01

The air entrainment and free-surface fluctuations caused by the interaction of a free surface and the turbulent boundary layer of a vertical surface-piercing plate is studied experimentally. In this experiment, a meter-wide stainless steel belt travels horizontally in a loop around two rollers with vertically oriented axes. This belt device is mounted inside a large water tank with the water level set just below the top edge of the belt. The belt, rollers, and supporting frame are contained within a sheet metal box to keep the device dry except for one 6-meter-long straight test section. The belt is accelerated suddenly from rest until reaching constant speed in order to create a temporally evolving boundary layer analogous to the spatially evolving boundary layer that would exist along a surface-piercing towed flat plate. Surface ripples are measured using a cinematic laser-induced fluorescence technique with the laser sheet oriented parallel or normal to the belt surface. Air entrainment events and bubble motions are recorded from underneath the water surface using a stereo imaging system. Measurements of small bubbles, that tend to stay submerged for a longer time, are planned via a high-speed digital in-line holographic system. The support of the Office of Naval Research is gratefully acknowledged.

26 CFR 1.430(h)(3)-2 - Plan-specific substitute mortality tables used to determine present value.

Code of Federal Regulations, 2012 CFR

2012-04-01

... paragraph (c)(1)(ii) of this section. Separate mortality tables must be established for each gender under the plan, and a substitute mortality table is permitted to be established for a gender only if the plan has credible mortality experience with respect to that gender. (ii) Credible mortality experience...

26 CFR 1.430(h)(3)-2 - Plan-specific substitute mortality tables used to determine present value.

Code of Federal Regulations, 2013 CFR

2013-04-01

... paragraph (c)(1)(ii) of this section. Separate mortality tables must be established for each gender under the plan, and a substitute mortality table is permitted to be established for a gender only if the plan has credible mortality experience with respect to that gender. (ii) Credible mortality experience...

26 CFR 1.430(h)(3)-2 - Plan-specific substitute mortality tables used to determine present value.

Code of Federal Regulations, 2014 CFR

2014-04-01

... paragraph (c)(1)(ii) of this section. Separate mortality tables must be established for each gender under the plan, and a substitute mortality table is permitted to be established for a gender only if the plan has credible mortality experience with respect to that gender. (ii) Credible mortality experience...

26 CFR 1.430(h)(3)-2 - Plan-specific substitute mortality tables used to determine present value.

Code of Federal Regulations, 2011 CFR

2011-04-01

... paragraph (c)(1)(ii) of this section. Separate mortality tables must be established for each gender under the plan, and a substitute mortality table is permitted to be established for a gender only if the plan has credible mortality experience with respect to that gender. (ii) Credible mortality experience...

Beginning Subbaccalaureate Students' Labor Market Experiences: Six Years Later in 2009. Web Tables. NCES 2012-273

ERIC Educational Resources Information Center

Ifill, Nicole; Radford, Alexandria Walton

2012-01-01

This set of Web Tables presents descriptive statistics on the spring 2009 labor market experiences of subbaccalaureate students who first entered postsecondary education in 2003-04. The Web Tables use data from the nationally representative 2004/09 Beginning Post-secondary Students Longitudinal Study (BPS:04/09), which followed a cohort of…

Comparison of predicted and experimental performance of large-bore roller bearing operating to 3.0 million DN

NASA Technical Reports Server (NTRS)

Coe, H. H.; Huller, F. T.

1980-01-01

Bearing inner and outer race temperatures and the amount of heat transferred to the lubricant were calculated by using the computer program CYBEAN. The results obtained were compared with previously reported experimental data for a 118 mm bore roller bearing that operated at shaft speeds to 25,500 rpm, radial loads to 8,900 N (2000 lb), and total lubricant flow rates to 0.0102 cu m/min (2.7 gal/min). The calculated results compared well with the experimental data.

Roller skating--is it a dangerous sport?

PubMed Central

Tse, P Y; Shen, W Y; Chan, K M; Leung, P C

1987-01-01

A prospective survey of 111 cases of roller skating injuries within one year are reported. Males were more commonly injured than females. There was a high incidence (86%) of serious injuries, 28% of which required surgical treatment. The wrist (23%) was the commonest region involved, followed by the shoulder (20%), the elbow (15%) and the ankle (12%). Collision with other skaters and loss of control were the main factors leading to injury. Better rink discipline, instruction classes and safety publicity should be helpful in minimising accidents. Images Fig. 2 & Fig. 3 PMID:3676638

Computer Program for Analysis of High Speed, Single Row, Angular Contact, Spherical Roller Bearing, SASHBEAN. Volume 2: Mathematical Formulation and Analysis

DTIC Science & Technology

1993-09-01

conformity of roller and raceway spherical crowns, while lending the bearing its self -aligning and high load capacity, also results in relative sliding...thus in the negative direction. A positive axial load, acting along the X-axis is also shown in Figure 1. Due to the self -aligning ability of a...34Pubdic irevmln bude tI thui cftlction of mntorniaton e =-mtmiaed to =,..iage 1 hour per respose . incuding the tme for rewiwng Insruc.tions

Abrasion Resistance and Mechanical Properties of Waste-Glass-Fiber-Reinforced Roller-compacted Concrete

NASA Astrophysics Data System (ADS)

Yildizel, S. A.; Timur, O.; Ozturk, A. U.

2018-05-01

The potential use of waste glass fibers in roller-compacted concrete (RCC) was investigated with the aim to improve its performance and reduce environmental effects. The research was focused on the abrasion resistance and compressive and flexural strengths of the reinforced concrete relative to those of reference mixes without fibers. The freeze-thaw resistance of RCC mixes was also examined. It was found that the use of waste glass fibers at a rate of 2 % increased the abrasion resistance of the RCC mixes considerably.

Sidewall containment of liquid metal with vertical alternating magnetic fields

DOEpatents

Lari, R.J.; Praeg, W.F.; Turner, L.R.; Battles, J.E.; Hull, J.R.; Rote, D.M.

1990-12-04

An apparatus is disclosed for containing molten metal using a magnet producing vertical alternating magnetic field positioned adjacent the area in which the molten metal is to be confined. This invention can be adapted particularly to the casting of metal between counter-rotating rollers with the vertical alternating magnetic field used to confine the molten metal at the edges of the rollers. Alternately, the vertical alternating magnetic field can be used as a flow regulator in casting molten metal from an opening in a channel. 9 figs.

Sidewall containment of liquid metal with vertical alternating magnetic fields

DOEpatents

Lari, R.J.; Praeg, W.F.; Turner, L.R.; Battles, J.E.; Hull, J.R.; Rote, D.M.

1988-06-17

An apparatus for containing molten metal using a magnet producing vertical alternating magnetic field positioned adjacent to the area in which the molten metal is to be confined. This invention can be adapted particularly to the casting of metal between counter-rotating rollers with the vertical alternating magnetic field used to confine the molten metal at the edges of the rollers. Alternately, the vertical alternating magnetic field can be used as a flow regulator in casting molten metal from an opening in a channel. 8 figs.

Lubrication and Cooling Studies of Cylindrical-Roller Bearings at High Speeds

NASA Technical Reports Server (NTRS)

Macks, E Fred; Nemeth, Zolton N

1952-01-01

The results of an experimental investigation of the effect of oil inlet distribution and oil inlet temperature on the inner and outer-race temperatures of 75-millimeter-bore (size 215) cylindrical-roller inner-race-riding cage-type bearings are reported. A radial-load test rig was used over a range of dn values (product of the bearing bore in mm and the shaft speed in r.p.m) from 0.3 x 10(5) to 1.2 x 10(6) and static radial loads from 7 to 1113 pounds.

Spherical roller bearing analysis. SKF computer program SPHERBEAN. Volume 3: Program correlation with full scale hardware tests

NASA Technical Reports Server (NTRS)

Kleckner, R. J.; Rosenlieb, J. W.; Dyba, G.

1980-01-01

The results of a series of full scale hardware tests comparing predictions of the SPHERBEAN computer program with measured data are presented. The SPHERBEAN program predicts the thermomechanical performance characteristics of high speed lubricated double row spherical roller bearings. The degree of correlation between performance predicted by SPHERBEAN and measured data is demonstrated. Experimental and calculated performance data is compared over a range in speed up to 19,400 rpm (0.8 MDN) under pure radial, pure axial, and combined loads.

Effects of water table position and plant functional group on plant community, aboveground production, and peat properties in a peatland mesocosm experiment (PEATcosm)

Treesearch

Lynette R. Potvin; Evan S. Kane; Rodney A. Chimner; Randall K. Kolka; Erik A. Lilleskov

2015-01-01

Aims Our objective was to assess the impacts of water table position and plant functional type on peat structure, plant community composition and aboveground plant production. Methods We initiated a full factorial experiment with 2 water table (WT) treatments (high and low) and 3 plant functional groups (PFG: sedge, Ericaceae,...

Life-table methods for detecting age-risk factor interactions in long-term follow-up studies.

PubMed

Logue, E E; Wing, S

1986-01-01

Methodological investigation has suggested that age-risk factor interactions should be more evident in age of experience life tables than in follow-up time tables due to the mixing of ages of experience over follow-up time in groups defined by age at initial examination. To illustrate the two approaches, age modification of the effect of total cholesterol on ischemic heart disease mortality in two long-term follow-up studies was investigated. Follow-up time life table analysis of 116 deaths over 20 years in one study was more consistent with a uniform relative risk due to cholesterol, while age of experience life table analysis was more consistent with a monotonic negative age interaction. In a second follow-up study (160 deaths over 24 years), there was no evidence of a monotonic negative age-cholesterol interaction by either method. It was concluded that age-specific life table analysis should be used when age-risk factor interactions are considered, but that both approaches yield almost identical results in absence of age interaction. The identification of the more appropriate life-table analysis should be ultimately guided by the nature of the age or time phenomena of scientific interest.

Effects of a Gentle, Self-Administered Stimulation of Perineal Skin for Nocturia in Elderly Women: A Randomized, Placebo-Controlled, Double-Blind Crossover Trial

PubMed Central

Iimura, Kaori; Watanabe, Nobuhiro; Masunaga, Koichi; Miyazaki, Shogo; Hotta, Harumi; Kim, Hunkyung; Hisajima, Tatsuya; Takahashi, Hidenori; Kasuya, Yutaka

2016-01-01

Background Somatic afferent nerve stimuli are used for treating an overactive bladder (OAB), a major cause of nocturia in the elderly. Clinical evidence for this treatment is insufficient because of the lack of appropriate control stimuli. Recent studies on anesthetized animals show that gentle stimuli applied to perineal skin with a roller could inhibit micturition contractions depending on the roller’s surface material. We examined the efficacy of gentle skin stimuli for treating nocturia. Methods The study was a cross-over, placebo-controlled, double-blind randomized clinical study using two rollers with different effects on micturition contractions. Participants were elderly women (79–89 years) with nocturia. Active (soft elastomer roller) or placebo (hard polystyrene roller) stimuli were applied to perineal skin by participants for 1 min at bedtime. A 3-day baseline assessment period was followed by 3-day stimulation and 4-day resting periods, after which the participants were subjected to other stimuli for another 3 days. The primary outcome was change in the frequency of nighttime urination, for which charts were maintained during each 3-day period. Results Twenty-four participants were randomized, of which 22 completed all study protocols. One participant discontinued treatment because of an adverse event (abdominal discomfort). In participants with OAB (n = 9), change from baseline in the mean frequency of urination per night during the active stimuli period (mean ± standard deviation, −0.74 ± 0.7 times) was significantly greater than that during placebo stimuli periods (−0.15 ± 0.8 times [p < 0.05]). In contrast, this difference was not observed in participants without OAB (n = 13). Conclusions These results suggest that gentle perineal stimulation with an elastomer roller is effective for treating OAB-associated nocturia in elderly women. Here the limitation was a study period too short to assess changes in the quality of sleep and life. Trial Registration UMIN Clinical Trial Registry (CTR) UMIN000015809 PMID:27003163

Nuclear Planetology: Constraining the Driving Force in Wegener's Continental Drift Theory

NASA Astrophysics Data System (ADS)

Roller, G.

2015-12-01

Nuclear planetology [1] is a new research field, which aims at deciphering the nuclear physics processes responsible for the evolution of ultra-substellar objects and the driving force in Wegener's continental drift theory by means of Re-Os nuclear geochronometry [2]. Terrestrial Re/Os ratios observed within diamond sulphide inclusions [3], compatible with lunar r-process production ratios of Th/U≈1≈Au/Ir [4], drop from ≈0.8 to 0.2-0.05 for nucleogeochronometric ages between 2.3 Ga and 1.4 Ga [5]. It has therefore been argued [5,6] that the Re/Os fractionation is related to a change in oxygen fugacity due to the physics/chemistry of Earth's core after a possibly Fermi-pressure controlled core collapse [4]. Here, Pd/Ru, Pd/Pt, Pd/Ir, Pd/Os, Ru/Ir, Ru/Os, Pt/Ir or Pt/Os ratios from 24 published H chondrite components [7] are connected to their respective nucleogeochronometric ages to constrain an extended fossil fractionation record over 800 Ma. The following ranges are obtained: 0.06-1.04 (Pd/Ru), 0.06-0.79 (Pd/Pt), 0.06-1.76 (Pd/Os), 0.07-1.94 (Pd/Ir), 1.08-1.99 (Ru/Ir), 0.83-2.41 (Pt/Os), 0.82-2.64 (Pt/Ir). Comparing the Re/Os fractionation pattern of the diamond sulphide inclusions with these results and considering that Re is readily oxidized even at ultra-low oxygen fugacity, it may be concluded that (i) extremely reducing conditions within Earth's core basically preserve any unfractionated r-process element ratio until today; and (ii) nuclear/quantum physics processes leading to the observed ratios and fractionation pattern are ultimately the driving force in Wegener's continental drift theory. [1] Roller (2015), Abstract T34B-0407, AGU Spring Meeting. [2] Roller (2015), Geophys. Res. Abstr. 17, EGU2015-17. [3] Smit et al. (2010), GCA 74, 3292. [4] Roller (2015), Abstract #5041, 78th Ann. Met. Soc. Meeting. [5] Roller (2015), Geophys. Res. Abstr. 17, EGU2015-2399. [6] Roller (2015), Abstract PG34A-0283, AGU Spring Meeting. [7] Horan et al. (2009), GCA 73, 6984.

Computer program for analysis of high speed, single row, angular contact, spherical roller bearing, SASHBEAN. Volume 1: User's guide

NASA Technical Reports Server (NTRS)

Aggarwal, Arun K.

1993-01-01

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 and view the contents of output files on the monitor screen if no paper printouts are required. A separate volume (Volume-2) of this documentation describes, in detail, the underlying mathematical formulations, assumptions, and solution algorithms of this program.

The influence of API concentration on the roller compaction process: modeling and prediction of the post compacted ribbon, granule and tablet properties using multivariate data analysis.

PubMed

Boersen, Nathan; Carvajal, M Teresa; Morris, Kenneth R; Peck, Garnet E; Pinal, Rodolfo

2015-01-01

While previous research has demonstrated roller compaction operating parameters strongly influence the properties of the final product, a greater emphasis might be placed on the raw material attributes of the formulation. There were two main objectives to this study. First, to assess the effects of different process variables on the properties of the obtained ribbons and downstream granules produced from the rolled compacted ribbons. Second, was to establish if models obtained with formulations of one active pharmaceutical ingredient (API) could predict the properties of similar formulations in terms of the excipients used, but with a different API. Tolmetin and acetaminophen, chosen for their different compaction properties, were roller compacted on Fitzpatrick roller compactor using the same formulation. Models created using tolmetin and tested using acetaminophen. The physical properties of the blends, ribbon, granule and tablet were characterized. Multivariate analysis using partial least squares was used to analyze all data. Multivariate models showed that the operating parameters and raw material attributes were essential in the prediction of ribbon porosity and post-milled particle size. The post compacted ribbon and granule attributes also significantly contributed to the prediction of the tablet tensile strength. Models derived using tolmetin could reasonably predict the ribbon porosity of a second API. After further processing, the post-milled ribbon and granules properties, rather than the physical attributes of the formulation were needed to predict downstream tablet properties. An understanding of the percolation threshold of the formulation significantly improved the predictive ability of the models.

High-energy roller injuries to the upper extremity.

PubMed

Askins, G; Finley, R; Parenti, J; Bush, D; Brotman, S

1986-12-01

Eleven cases of high-energy industrial roller injuries treated between 1980 and 1984 were retrospectively reviewed. The dominant extremity was affected in nine. Six patients sustained fractures and/or dislocations, and three of these patients required fasciotomies for clinical signs of impending compartment syndromes. All fracture/dislocations, with the exception of a scapula fracture, anterior dislocation of a thumb interphalangeal joint, and a fractured coronoid process of the ulna, required open reduction with internal fixation. Three patients required split-thickness skin grafting for extensive skin degloving. Two patients required immediate amputation. Late sequelae included prolonged edema, nutritional depletion, neuroma formation of the superficial branch of the radial nerve, late carpal tunnel syndrome, and partial brachial plexus palsy. Industrial roller injuries continue to be an occupational hazard associated with more severe crushing trauma than the low-energy wringer washer injuries first described by MacCollum (11). Attention must be paid to the treatment of crushed skin, muscle, and nerves, fracture stabilization, nutritional support, and occupational therapy. Concurrent monitoring for signs of a developing compartment syndrome and complications of rhabdomyolysis is essential.

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

PubMed Central

Kwak, Dae-Ho; Lee, Dong-Han; Ahn, Jong-Hyo; Koh, Bong-Hwan

2014-01-01

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. PMID:24368701

Lived Experience among Patients Newly Diagnosed with Lung Adenocarcinoma Stage IV within One Year.

PubMed

Shih, Whei-Mei Jean; Hsu, Hsiu-Chin; Jiang, Ru-Shang; Lin, Mei-Hsiang

2015-01-01

lung cancer (LC) is the fifth of the 10 leading causes of death in the world. LC is in first place for cancer-related mortality for both males and females in Taiwan. It is one of the most difficult cancers to treat and is often diagnosed at a late stage. Patients with stage IV are often unprepared for the diagnosis. To explore lived experience among patients newly diagnosed with lung adenocarcinoma stage IV within one year. Twelve participants were recruited in this study. Content analysis of the interviews revealed four themes: (1) emotional roller coaster, (2) trying to find out causes, (3) adjusting my lifestyle, and (4) cancer fighter. This study provides new insight into the experiences of lung cancer patients y with newly diagnosed lung adenocarcinoma stage 4. These results will inform future supportive care service development and intervention research for patients with advanced stage cancer.

The Communicability of Graphical Alternatives to Tabular Displays of Statistical Simulation Studies

PubMed Central

Cook, Alex R.; Teo, Shanice W. L.

2011-01-01

Simulation studies are often used to assess the frequency properties and optimality of statistical methods. They are typically reported in tables, which may contain hundreds of figures to be contrasted over multiple dimensions. To assess the degree to which these tables are fit for purpose, we performed a randomised cross-over experiment in which statisticians were asked to extract information from (i) such a table sourced from the literature and (ii) a graphical adaptation designed by the authors, and were timed and assessed for accuracy. We developed hierarchical models accounting for differences between individuals of different experience levels (under- and post-graduate), within experience levels, and between different table-graph pairs. In our experiment, information could be extracted quicker and, for less experienced participants, more accurately from graphical presentations than tabular displays. We also performed a literature review to assess the prevalence of hard-to-interpret design features in tables of simulation studies in three popular statistics journals, finding that many are presented innumerately. We recommend simulation studies be presented in graphical form. PMID:22132184

The communicability of graphical alternatives to tabular displays of statistical simulation studies.

PubMed

Cook, Alex R; Teo, Shanice W L

2011-01-01

Simulation studies are often used to assess the frequency properties and optimality of statistical methods. They are typically reported in tables, which may contain hundreds of figures to be contrasted over multiple dimensions. To assess the degree to which these tables are fit for purpose, we performed a randomised cross-over experiment in which statisticians were asked to extract information from (i) such a table sourced from the literature and (ii) a graphical adaptation designed by the authors, and were timed and assessed for accuracy. We developed hierarchical models accounting for differences between individuals of different experience levels (under- and post-graduate), within experience levels, and between different table-graph pairs. In our experiment, information could be extracted quicker and, for less experienced participants, more accurately from graphical presentations than tabular displays. We also performed a literature review to assess the prevalence of hard-to-interpret design features in tables of simulation studies in three popular statistics journals, finding that many are presented innumerately. We recommend simulation studies be presented in graphical form.

ASRM Case Insulation development

NASA Technical Reports Server (NTRS)

Tam, W. F. S.; Bell, M.

1993-01-01

The ASRM Case Insulation Program used design of experiments to develop a high performance case insulation. The program traded-off more than thirty properties in areas of ablation performance, material properties, processibility, bonding/aging. Kevlar pulp was found to be the most significant factor. The low-molecular weight ethylene propylene diene monomer, EPDM was the second most significant factor. The curative was the third most significant factor. The tackifier was the fourth most significant factor. The stripwinding process for applying the insulation onto the case inner surfaces was also studied. The parameters selected for experiment were extruder speed, upper roller temperature and extruder nozzle temperature. The extrudability results showed that non-Kevlar filled formulations displayed optimum edges but poor thickness continuity. High Kevlar filled formulations displayed optimum thickness continuity but poor strip edge ratings.

ASRM Case Insulation development

NASA Astrophysics Data System (ADS)

Tam, W. F. S.; Bell, M.

1993-06-01

The ASRM Case Insulation Program used design of experiments to develop a high performance case insulation. The program traded-off more than thirty properties in areas of ablation performance, material properties, processibility, bonding/aging. Kevlar pulp was found to be the most significant factor. The low-molecular weight ethylene propylene diene monomer, EPDM was the second most significant factor. The curative was the third most significant factor. The tackifier was the fourth most significant factor. The stripwinding process for applying the insulation onto the case inner surfaces was also studied. The parameters selected for experiment were extruder speed, upper roller temperature and extruder nozzle temperature. The extrudability results showed that non-Kevlar filled formulations displayed optimum edges but poor thickness continuity. High Kevlar filled formulations displayed optimum thickness continuity but poor strip edge ratings.

Flowing Active Liquids in a Pipe: Hysteretic Response of Polar Flocks to External Fields

NASA Astrophysics Data System (ADS)

Morin, Alexandre; Bartolo, Denis

2018-04-01

We investigate the response of colloidal flocks to external fields. We first show that individual colloidal rollers align with external flows, as would a classical spin with magnetic fields. Assembling polar active liquids from colloidal rollers, we experimentally demonstrate their hysteretic response: Confined colloidal flocks can proceed against external flows. We theoretically explain this collective robustness, using an active hydrodynamic description, and show how orientational elasticity and confinement protect the direction of collective motion. Finally, we exploit the intrinsic bistability of confined active flows to devise self-sustained microfluidic oscillators.

Research report: User's manual for computer program AT81y003 SHABERTH. Steady state and transient thermal analysis of a shaft bearing system including ball, cylindrical and tapered roller bearings

NASA Technical Reports Server (NTRS)

Hadden, G. B.; Kleckner, R. J.; Ragen, M. A.; Sheynin, L.

1981-01-01

The SHABERTH program is capable of simulating the thermomechanical performance of a load support system consisting of a flexible shaft supported by up to five rolling element bearings. Any combination of ball, cylindrical, and tapered roller bearings can be used to support the shaft. The user can select models in calculating lubricant film thickness and traction forces. The formulation of the cage pocket/rolling element interaction model was revised to improve solution numerical convergence characteristics.

Application of the Finite Element Method to Reveal the Causes of Loss of Planeness of Hot-Rolled Steel Sheets during Laser Cutting

NASA Astrophysics Data System (ADS)

Garber, E. A.; Bolobanova, N. L.; Trusov, K. A.

2018-01-01

A finite element technique is developed to simulate the stresses and the strains during strip flattening to reveal the causes of the cutting-assisted loss of planeness of hot-rolled steel sheets processed in roller levelers. The loss of planeness is found to be caused by a nonuniform distribution of the flattening-induced longitudinal tensile stresses over the strip thickness and width. The application of tensile forces to a strip in a roller leveler decreases this nonuniformity and prevents loss of planeness in cutting.

Multiroller traction drive speed reducer: Evaluation for automotive gas turbine engine

NASA Technical Reports Server (NTRS)

Rohn, D. A.; Anderson, N. E.; Loewenthal, S. H.

1982-01-01

Tests were conducted on a nominal 14:1 fixed-ratio Nasvytis multiroller traction drive retrofitted as the speed reducer in an automotive gas turbine engine. Power turbine speeds of 45,000 rpm and a drive output power of 102 kW (137 hp) were reached. The drive operated under both variable roller loading (proportional to torque) and fixed roller loading (automatic loading mechanism locked). The drive operated smoothly and efficiently as the engine speed reducer. Engine specific fuel consumption with the traction speed reducer was comparable to that with the original helical gearset.

Help for the Steel Industry

NASA Technical Reports Server (NTRS)

1991-01-01

A collaboration between NASA Lewis Research Center (LRC) and Gladwin Engineering resulted in the adaptation of aerospace high temperature metal technology to the continuous casting of steel. The continuous process is more efficient because it takes less time and labor. A high temperature material, once used on the X-15 research plane, was applied to metal rollers by a LRC developed spraying technique. Lewis Research Center also supplied mold prototype of metal composites, reducing erosion and promoting thermal conductivity. Rollers that previously cracked due to thermal fatigue, lasted longer. Gladwin's sales have increased, and additional NASA-developed innovations are anticipated.

Mechanical efficiency of two commercial lever-propulsion mechanisms for manual wheelchair locomotion.

PubMed

Lui, Jordon; MacGillivray, Megan K; Sheel, A William; Jeyasurya, Jeswin; Sadeghi, Mahsa; Sawatzky, Bonita Jean

2013-01-01

The purpose of this study was to (1) evaluate the mechanical efficiency (ME) of two commercially available lever-propulsion mechanisms for wheelchairs and (2) compare the ME of lever propulsion with hand rim propulsion within the same wheelchair. Of the two mechanisms, one contained a torsion spring while the other used a roller clutch design. We hypothesized that the torsion spring mechanism would increase the ME of propulsion due to a passive recovery stroke enabled by the mechanism. Ten nondisabled male participants with no prior manual wheeling experience performed submaximal exercise tests using both lever-propulsion mechanisms and hand rim propulsion on two different wheelchairs. Cardiopulmonary parameters including oxygen uptake (VO2), heart rate (HR), and energy expenditure (En) were determined. Total external power (Pext) was measured using a drag test protocol. ME was determined by the ratio of Pext to En. Results indicated no significant effect of lever-propulsion mechanism for all physiological measures tested. This suggests that the torsion spring did not result in a physiological benefit compared with the roller clutch mechanism. However, both lever-propulsion mechanisms showed decreased VO2 and HR and increased ME (as a function of slope) compared with hand rim propulsion (p < 0.001). This indicates that both lever-propulsion mechanisms tested are more mechanically efficient than conventional hand rim propulsion, especially when slopes are encountered.

Documentation of roller-bearing effect on butterfly inspired grooves

NASA Astrophysics Data System (ADS)

Gautam, Sashank; Lang, Amy

2017-11-01

Butterfly wings are covered with scales in a roof shingle pattern which align together to form grooves. The increase or decrease of laminar friction drag depends on the flow orientation to the scales. Flow in the longitudinal direction to the grooves encounters increased surface area which increases the friction drag. However, in the transverse direction, for low Re laminar flow, a single vortex is formed inside each groove and is predicted to remain stable due to the very low Re of the flow in each cavity. These embedded vortices act as roller bearings to the flow above, such that the fluid from the outer boundary layer does not mix with fluid inside the cavities. This leads to a reduction of skin friction drag when compared to a smooth surface. When the cavity flow Re is increased beyond a critical point, the vortex becomes unstable and the low-momentum fluid in the grooves mixes with the outer boundary layer flow, increasing the drag. The objective of this experiment is to determine the critical Re where the embedded vortex transitions from a stable to an unstable state using DPIV. Subsequently, for steady vortex conditions, a comparison of skin friction drag between the grooved and flat plate can show that the butterfly scaled surface can result in sub-laminar friction drag. The National Science Foundation (Grant No. 1335848).

An Investigation of the Effects of Deposit Feeding Invertebrates on the Structural Properties of Clay Minerals.

DTIC Science & Technology

1981-07-01

Dennis M. Lavoie of NORDA for chemical analysis of clay minerals with the x-ray energy dispersive spectrometer. We thank Fred Bowles, Peter Fleischer...diffractograi of Nuculana acuta fecal pellet 11 residue (illite experiment). TABLES TABLE 1. X-ray energy dispersive spectrometer chemical 8 analysis for...inontmorillonite experiments. Counts for elements after background counts removed. TABLE 2. X-ray energy dispersive spectroneter chemical analysis 12 for

Investigation of the phenomenon of electrostatic compromise of a plastic fiber heat exchanger.

PubMed

Elgas, R J

1999-03-01

The use of a new generation of blood oxygenator design using plastic fibers for the heat exchange material is growing. The benefits of a plastic heat exchange material are improved biocompatibility and performance over some of the traditional metals used. During the initial period of clinical use of one of these new oxygenators, there were reports of four blood-to-water leaks. No patient complications were associated with these leaks, but the product was withdrawn from the market. After a thorough evaluation, the cause of the leaks was found to be an electrostatic discharge that occurred within the heat exchanger during priming of the extracorporeal circuit. It was found that an electrostatic potential between the blood path and the water path of the heat exchanger is generated as the prime solution is recirculated by a roller pump with polyvinyl chloride (PVC) pumphead tubing. The magnitude of the potential generated was found to vary with the make and model of the roller pump. If this voltage exceeds the dielectric strength of the fiber, a discharge through the wall of a single heat exchange fiber will occur and produce a hole. Several solutions to this problem of roller pumps generating an electrostatic charge when used with PVC pumphead tubing were identified. Centrifugal blood pumps and roller pumps using silicone rubber pumphead tubing were found to generate no significant electrostatic potential between the blood path and the water path. Another solution, a charge equalization line (CEL), was designed to provide a conductive path for the charge to equilibrate across the fiber wall. The CEL can be either external or internal to the oxygenator. Each of these solutions was validated and the product has been reintroduced for clinical use.

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

PubMed

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.

Changes in technique and efficiency after high-intensity exercise in cross-country skiers.

PubMed

Åsan Grasaas, Christina; Ettema, Gertjan; Hegge, Ann Magdalen; Skovereng, Knut; Sandbakk, Øyvind

2014-01-01

This study investigated changes in technique and efficiency after high-intensity exercise to exhaustion in elite cross-country skiers. Twelve elite male skiers completed 4 min submaximal exercise before and after a high-intensity incremental test to exhaustion with the G3 skating technique on a 5% inclined roller-ski treadmill. Kinematics and kinetics were monitored by instrumented roller skis, work rate was calculated as power against roller friction and gravity, aerobic metabolic cost was determined from gas exchange, and blood lactate values indicated the anaerobic contribution. Gross efficiency was the work rate divided by aerobic metabolic rate. A recovery period of 10 min between the incremental test and the posttest was included to allow the metabolic values to return to baseline. Changes in neuromuscular fatigue in upper and lower limbs before and after the incremental test were indicated by peak power in concentric bench press and squat-jump height. From pretest to posttest, cycle length decreased and cycle rate increased by approximately 5% (P < 0.001), whereas the amount of ski forces did not change significantly. Oxygen uptake increased by 4%, and gross efficiency decreased from 15.5% ± 0.7% to 15.2% ± 0.5% from pretest to posttest (both P < .02). Correspondingly, blood lactate concentration increased from 2.4 ± 1.0 to 6.2 ± 2.5 mmol/L (P < .001). Bench-press and squat-jump performance remained unaltered. Elite cross-country skiers demonstrated a less efficient technique and shorter cycle length during submaximal roller-ski skating after high-intensity exercise. However, there were no changes in ski forces or peak power in the upper and lower limbs that could explain these differences.

Cycling on rollers: influence of tyre pressure and cross section on power requirements.

PubMed

Reiser, Raoul; Watt, Jon; Peterson, Michael

2003-07-01

The resistance against a cyclist while riding on rollers is due mainly to rolling resistance produced by the deformation of the tyre as it rolls against small diameter drums. Resistance is then combined with wheel speed to set power output. The effect of tyre pressure and cross-section on power was investigated by systematically altering the pressure (552 kPa, 690 kPa, and 827 KPa) in a 20c, 23c, 25c, and 28c tyre of the same design while riding at a wheel speed of 45 kph. Average power over 1 minute was measured with a Power Tap Hub (Tune Corporation, Cambridge, Massachusetts, USA) on five occasions. Statistical significance was evaluated at p < 0.05. Power requirements increased significantly with each reduction in tyre pressure for all tyres and pressures except the 25c between 690 and 827 kPa. The 20c tyre required significantly more power from the cyclist at each tested tyre pressure when compared to the other tyres (which were not different from each other). The differences in resistance from tyre size were not observed when ridden on the road. Additionally, a slightly different tyre design from the same manufacturer responded similarly in the 20c, but was significantly different in the 23c size. It was also observed that power requirements increased significantly when both the wheels were ridden on the rollers as compared to just the rear wheel. These results indicate that the power requirements may be significantly altered by the cyclist by adjusting tyre pressure, tyre cross-section size, tyre type, and with the number of wheels contacting the rollers. However, the magnitude of these power requirements may not be suitable for intense workouts of trained cyclists.

Beyond velocity and acceleration: jerk, snap and higher derivatives

NASA Astrophysics Data System (ADS)

Eager, David; Pendrill, Ann-Marie; Reistad, Nina

2016-11-01

The higher derivatives of motion are rarely discussed in the teaching of classical mechanics of rigid bodies; nevertheless, we experience the effect not only of acceleration, but also of jerk and snap. In this paper we will discuss the third and higher order derivatives of displacement with respect to time, using the trampolines and theme park roller coasters to illustrate this concept. We will also discuss the effects on the human body of different types of acceleration, jerk, snap and higher derivatives, and how they can be used in physics education to further enhance the learning and thus the understanding of classical mechanics concepts.

Spectral Retrieval of Latent Heating Profiles from TRMM PR Data: Comparison of Look-Up Tables

NASA Technical Reports Server (NTRS)

Shige, Shoichi; Takayabu, Yukari N.; Tao, Wei-Kuo; Johnson, Daniel E.; Shie, Chung-Lin

2003-01-01

The primary goal of the Tropical Rainfall Measuring Mission (TRMM) is to use the information about distributions of precipitation to determine the four dimensional (i.e., temporal and spatial) patterns of latent heating over the whole tropical region. The Spectral Latent Heating (SLH) algorithm has been developed to estimate latent heating profiles for the TRMM Precipitation Radar (PR) with a cloud- resolving model (CRM). The method uses CRM- generated heating profile look-up tables for the three rain types; convective, shallow stratiform, and anvil rain (deep stratiform with a melting level). For convective and shallow stratiform regions, the look-up table refers to the precipitation top height (PTH). For anvil region, on the other hand, the look- up table refers to the precipitation rate at the melting level instead of PTH. For global applications, it is necessary to examine the universality of the look-up table. In this paper, we compare the look-up tables produced from the numerical simulations of cloud ensembles forced with the Tropical Ocean Global Atmosphere (TOGA) Coupled Atmosphere-Ocean Response Experiment (COARE) data and the GARP Atlantic Tropical Experiment (GATE) data. There are some notable differences between the TOGA-COARE table and the GATE table, especially for the convective heating. First, there is larger number of deepest convective profiles in the TOGA-COARE table than in the GATE table, mainly due to the differences in SST. Second, shallow convective heating is stronger in the TOGA COARE table than in the GATE table. This might be attributable to the difference in the strength of the low-level inversions. Third, altitudes of convective heating maxima are larger in the TOGA COARE table than in the GATE table. Levels of convective heating maxima are located just below the melting level, because warm-rain processes are prevalent in tropical oceanic convective systems. Differences in levels of convective heating maxima probably reflect differences in melting layer heights. We are now extending our study to simulations of other field experiments (e.g. SCSMEX and ARM) in order to examine the universality of the look-up table. The impact of look-up tables on the retrieved latent heating profiles will also be assessed.

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

PubMed

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. Published by Elsevier B.V.

Research on the Influence of Weighing Accuracy Caused by the Position of Tension Wheel on the Electronic Belt-Conveyor Scale

NASA Astrophysics Data System (ADS)

Zhang, Kun; Zhang, Hu; Song, Qiuzhi

2018-01-01

In this paper, a Single- Idler electronic belt-conveyor scale is the Object of study. The contact force between the belt and the supporting roller is calculated by the finite element analysis software ABAQUS. The relationship between the tension distance of the tension wheel and the contact force between the belt and the weighing roller is obtained. The best stretching distance is found through analysis. And the conclusion which is the weighing error is different at the same stretching distance but the different weight of material is obtained. A compensation mechanism is proposed to improve the weighing accuracy.

Effect of speed and press fit on fatigue life of roller-bearing inner-race contact

NASA Technical Reports Server (NTRS)

Coe, H. H.; Zaretsky, E. V.

1985-01-01

An analysis was performed to determine the effects of inner ring speed and press fit on the rolling element fatigue life of a roller bearing inner race contact. The effects of the resultant hoop and radial stresses on the principal stresses were considered. The maximum shear stresses below the Hertzian contact were determined for different conditions of inner ring speed, load, and geometry and were applied to a conventional ring life analysis. The race contact fatigue life was reduced by more than 90 percent for some conditions when speed and press fit were considered. The depth of the maximum shear stress remained virtually unchanged.

Analysis of mixed-mode crack propagation using the boundary integral method

NASA Technical Reports Server (NTRS)

Mendelson, A.; Ghosn, L. J.

1986-01-01

Crack propagation in a rotating inner raceway of a high speed roller bearing is analyzed using the boundary integral equation method. The method consists of an edge crack in a plate under tension, upon which varying Hertzian stress fields are superimposed. A computer program for the boundary integral equation method was written using quadratic elements to determine the stress and displacement fields for discrete roller positions. Mode I and Mode II stress intensity factors and crack extension forces G sub 00 (energy release rate due to tensile opening mode) and G sub r0 (energy release rate due to shear displacement mode) were computed. These calculations permit determination of that crack growth angle for which the change in the crack extension forces is maximum. The crack driving force was found to be the alternating mixed-mode loading that occurs with each passage of the most heavily loaded roller. The crack is predicted to propagate in a step-like fashion alternating between radial and inclined segments, and this pattern was observed experimentally. The maximum changes DeltaG sub 00 and DeltaG sub r0 of the crack extension forces are found to be good measures of the crack propagation rate and direction.

Effect of Processing Variables on Tensile Modulus and Morphology of Polyethylene/Clay Nanocomposites Prepared in an Internal Mixer

NASA Astrophysics Data System (ADS)

Ujianto, O.; Jollands, M.; Kao, N.

2018-03-01

A comparative study on effect of internal mixer on high density Polyethylene (HDPE)/clay nanocomposites preparation was done. Effect of temperature, rotor rotation (rpm), and mixing time, as well as rotor type (Roller and Banbury) on mechanical properties and morphology of HDPE/clay nanocomposites were studied using Box-Behnken experimental design. The model was developed according to secant modulus and confirmed to morphology analysis using Transmission Electron Microscopy (TEM). The finding suggests that there is different mechanisms occurred in each rotor to improve the mechanical properties. The mechanism in Roller is medium shear and medium diffusion, while Banbury is high shear and low diffusion. The difference in mechanism to disperse the clay particles attribute to the different optimum processing conditions in each rotor. The settings for roller samples are predicted around mid temperature, mid speed, and mid mixing time. There is no optimum setting for Banbury within the processing boundaries. The best settings for Banbury are at low, high, low settings. The morphology results showed a hybrid composite structure, with some exfoliations and some intercalations. There was a correlation between better mechanical properties and morphology with more exfoliation and thinner intercalated particles.

Justification of the Shape of a Non-Circular Cross-Section for Drilling With a Roller Cutter

NASA Astrophysics Data System (ADS)

Buyalich, Gennady; Husnutdinov, Mikhail

2017-11-01

The parameters of the shape of non-circular cross-section affect not only the process of blasting, but also the design of the tool and the process of drilling as well. In the conditions of open-pit mining, it is reasonable to use a roller cutter to produce a non-circular cross-section of blasting holes. With regard to the roller cutter, the impact of the cross-section shape on the oscillations of the axial force arising upon its rotation is determined. It is determined that a polygonal shape with rounded comers of the borehole walls connections and their convex shape, which ensures a smaller range of the total axial force and the torque deflecting the bit from the axis of its rotation is the rational form of the non-circular cross-section of the borehole in terms of bit design. It has been shown that the ratio of the number of cutters to the number of borehole corners must be taken into account when justifying the shape of the cross-section, both from the point of view of the effectiveness of the explosion action and from the point of view of the rational design of the bit.

“Roller-Wheel”-Type Pt-Containing Small Molecules and the Impact of “Rollers” on Material Crystallinity, Electronic Properties, and Solar Cell Performance

DOE PAGES

He, Wenhan; Livshits, Maksim Y.; Dickie, Diane A.; ...

2017-07-21

We report the synthesis, characterization, and detailed comparison of a series of novel Pt-bisacetylide containing conjugated small molecules possessing an unconventional “roller-wheel” shaped structure that is distinctly different from the “dumbbell” designs in traditional Pt-bisacetylide containing conjugated polymers and small molecules. The relationships between the chemical nature and length of the “rollers” and the electronic and physical properties of the materials are carefully studied by steady-state spectroscopy, cyclic voltammetry, differential scanning calorimetry, single-crystal X-ray diffraction, transient absorption spectroscopy, theoretical calculation, and device application. It was revealed that if the roller are long enough, these molecules can “slip-stack” in the solidmore » state, leading to high crystallinity and charge mobility. Organic solar cells were fabricated and showed power conversion efficiencies up to 5.9%, out-performing all existing Pt-containing materials. The device performance was also found to be sensitive to optimization conditions and blend morphologies, which are a result of the intricate interplay among materials crystallinity, phase separation, and the relative positions of the lowest singlet and triplet excited states.« less

A Motion Simulator Ride Associated With Headache and Subdural Hematoma: First Case Report.

PubMed

Scranton, Robert A; Evans, Randolph W; Baskin, David S

2016-02-01

We report the first case report of symptomatic bilateral subdural hematomas (SDH) associated with riding a centrifugal motion simulator ride. A previously healthy 55-year-old male developed new onset daily headaches 1 week after going on the ride that were due to symptomatic bilateral SDH requiring operative intervention with a full recovery. There was no history of other trauma or other systemic or intracranial abnormality to account for the development of the SDH. We review the headaches and other clinical features associated with chronic SDH. Twelve cases of roller coaster headaches due to SDH associated with riding roller coasters have been reported. The pathophysiology is reviewed, which we believe is the same mechanism that may be responsible in this case. Although it is possible that this neurovascular injury is truly rare, it is also possible that this injury is underreported as patients and physicians may not make the association or physicians have not reported additional cases. The risk of this injury likely increases with age, as the size of the subdural space increases, and may support the maxim that "roller coasters and simulators are for kids." © 2015 American Headache Society.

Studies of worn surfaces by relocation profilometry

NASA Astrophysics Data System (ADS)

Rîpă, M.; Iliuță, V.

2018-01-01

By relocation profilometry, a series of surface profiles can be recorded from the same track on a specimen. These techniques are used for monitoring specific particular points on the surface subjected to wear processes, in a more accurate manner as comparing to those involving average statistical information for surface. The method is providing a much more significant information about the surface, in a more efficient way, assuring that the same unworn investigated surface is studied after wear test. The studied roughness digital profiles were obtained before and after the testing of rolling/sliding line contacts, characteristic for spur gears, which has been simulated on SAE sets, with a two rollers test machine. The acquisition of the relocated profiles is performed on the same generatrix of the roller, before and after wear testing. To correlate the unworn and worn profiles, a spheroconical indentation was created on the circumferential surface of the disk, in the zone of the tested roller that remain unworn during the test. Measuring changes of the profiles by relocation techniques, two methods for wear assessment are presented: linear wear estimation by simulating the profile wearing and estimation of the volume wear.

“Roller-Wheel”-Type Pt-Containing Small Molecules and the Impact of “Rollers” on Material Crystallinity, Electronic Properties, and Solar Cell Performance

DOE Office of Scientific and Technical Information (OSTI.GOV)

He, Wenhan; Livshits, Maksim Y.; Dickie, Diane A.

We report the synthesis, characterization, and detailed comparison of a series of novel Pt-bisacetylide containing conjugated small molecules possessing an unconventional “roller-wheel” shaped structure that is distinctly different from the “dumbbell” designs in traditional Pt-bisacetylide containing conjugated polymers and small molecules. The relationships between the chemical nature and length of the “rollers” and the electronic and physical properties of the materials are carefully studied by steady-state spectroscopy, cyclic voltammetry, differential scanning calorimetry, single-crystal X-ray diffraction, transient absorption spectroscopy, theoretical calculation, and device application. It was revealed that if the roller are long enough, these molecules can “slip-stack” in the solidmore » state, leading to high crystallinity and charge mobility. Organic solar cells were fabricated and showed power conversion efficiencies up to 5.9%, out-performing all existing Pt-containing materials. The device performance was also found to be sensitive to optimization conditions and blend morphologies, which are a result of the intricate interplay among materials crystallinity, phase separation, and the relative positions of the lowest singlet and triplet excited states.« less

Student Reasoning from Data Tables: Data Interpretation in Light of Student Ability and Prior Belief

NASA Astrophysics Data System (ADS)

Bogdan, Abigail Marie

Here I present my work studying introductory physics students proficiency with the control of variables strategy to evaluate simple data tables. In this research, a primary goal was to identify and to describe the reasoning strategies that students use preferentially when evaluating simple data tables where the control of variables strategy is the normative evaluation strategy. In addition, I aimed to identify and describe the factors that affect students reasoning strategies when analyzing these simple data tables. In a series of experiments, I tested 1,360 introductory physics students, giving them simple tables of experimental data to analyze. Generally, each of the experiments that I conducted had two conditions. In both of these conditions, the data filling the tables was identical; however, in the first condition, the data table was presented in a physical context and students were given a short pre-test to measure their beliefs about the context. In the second condition, the table was given in a more generic context. This was repeated with multiple data tables and physical contexts. In addition to the data table task, students were given several measures of cognitive ability. By using students answers on the pretest about physical context, I was able to measure whether or not each students prior beliefs were consistent with the relationships shown in the data tables. Across all the experiments conducted here, I found that those students whose prior beliefs were consistent with the data were over three times more likely to draw a valid inference from the table than students whose prior beliefs were inconsistent with the data. By further analyzing students responses, I found evidence that this difference in performance could be accounted for by the presence of a belief bias. Students tended to cite data in suboptimal ways, frequently treating their own theories as a source of evidence to be supplemented by or illustrated with examples from the data. Because of this tendency to hunt piecemeal through the tables for supporting examples, contradictory data was often simply overlooked. However, even when noticed, data that contradicted their theories was often ignored, misinterpreted to conform, or discounted in some way.

A new way to experience the International Gastric Cancer Association Congress: the Web Round Tables.

PubMed

Morgagni, Paolo; Verlato, Giuseppe; Marrelli, Daniele; Roviello, Franco; de Manzoni, Giovanni

2014-10-01

In an attempt to attract a wider diversity of professionals to the 10th International Gastric Cancer Association Congress (IGCC) held in June 2013, the Scientific Committee of the conference organized a number of pre-congress Web Round Tables to discuss cutting-edge topics relating to gastric cancer treatment. Twenty Web Round Tables, each coordinated by a different chairman, were proposed on the IGCC Website 1 year before the congress. Each chairman identified a number of studies related to the theme of his/her Round Table and invited corresponding authors to send an update of their conclusions in light of their subsequent experience, which would then form the basis of discussion of the Web Round Tables. The chairmen posted several questions regarding these updates on the web and opened a forum for a period of 1-2 months. The forum was free and specifically intended for congress participants. Fifty-one (9.9 %) of the 516 authors contacted took part in the initiative. Two hundred fifty participants from 21 countries joined the forum discussion and posted 671 comments. The Web Round Tables were viewed 15,810 times while the forum was open. Overall, the Web Round Tables aroused considerable interest, especially among young professionals working in the area of gastric cancer who had the opportunity to contact and interact with experts in what often turned out to be an interesting and lively exchange of views. All the discussions are now freely available for consultation on the IGCC website. The Web Round Table experience was presented, with great success, during the conference at special afternoon sessions.

TSP Symposium 2012 Proceedings

DTIC Science & Technology

2012-11-01

and Statistical Model 78 7.3 Analysis and Results 79 7.4 Threats to Validity and Limitations 85 7.5 Conclusions 86 7.6 Acknowledgments 87 7.7...Table 12: Overall Statistics of the Experiment 32 Table 13: Results of Pairwise ANOVA Analysis, Highlighting Statistically Significant Differences...we calculated the percentage of defects injected. The distribution statistics are shown in Table 2. Table 2: Mean Lower, Upper Confidence Interval

Calculating Toxic Corridors.

DTIC Science & Technology

1980-11-01

59 programmable calculator . Method 1 will most likely be used if there is a toxic corridor length table for the chemical; Method 2 if there is no table...experience of the forecaster in making this forecast, availability of a toxic corridor length table for the released chemical, and availability of a TI

Nuclear planetology: understanding planetary mantle and crust formation in the light of nuclear and particle physics

NASA Astrophysics Data System (ADS)

Roller, Goetz

2017-04-01

The Hertzsprung-Russell (HR) diagram is one of the most important diagrams in astronomy. In a HR diagram, the luminosity of stars and/or stellar remnants (white dwarf stars, WD's), relative to the luminosity of the sun, is plotted versus their surface temperatures (Teff). The Earth shows a striking similarity in size (radius ≈ 6.371 km) and Teff of its outer core surface (Teff ≈ 3800 K at the core-mantle-boundary) with old WD's (radius ≈ 6.300 km) like WD0346+246 (Teff ≈ 3820 K after ≈ 12.7 Ga [1]), which plot in the HR diagram close to the low-mass extension of the stellar population or main sequence. In the light of nuclear planetology [2], Earth-like planets are regarded as old, down-cooled and differentiated black dwarfs (Fe-C BLD's) after massive decompression, the most important nuclear reactions involved being 56Fe(γ,α)52Cr (etc.), possibly responsible for extreme terrestrial glaciations events ("snowball" Earth), together with (γ,n), (γ,p) and fusion reactions like 12C(α,γ)16O. The latter reaction might have caused oxidation of the planet from inside out. Nuclear planetology is a new research field, tightly constrained by a coupled 187Re-232Th-238U systematics [3-5]. By means of nuclear/quantum physics and taking the theory of relativity into account, it aims at understanding the thermal and chemical evolution of Fe-C BLD's after gravitational contraction (e.g. Mercury) or Fermi-pressure controlled collapse (e.g. Earth) events after massive decompression, leading possibly to an r-process event, towards the end of their cooling period [2]. So far and based upon 187Re-232Th-238U nuclear geochronometry, the Fe-C BLD hypothesis can successfully explain the global terrestrial MORB 232Th/238U signature [5]. Thus, it may help to elucidate the DM (depleted mantle), EMI (enriched mantle 1), EMII (enriched mantle 2) or HIMU (high U/Pb) reservoirs [6], and the 187Os/188Os isotopic dichotomy in Archean magmatic rocks and sediments [7]. Here I present a conceptual model constraining the evolution of a rocky planet like Earth or Mercury from a stellar precursor of the oldest population to a Fe-C BLD, shifting through different spectral classes in a HR diagram after massive decompression and tremendous energy losses. In the light of WD/BLD cosmochronology [1], solar system bodies like Earth, Mercury and Moon are regarded as captured interlopers from the Galactic bulge, Earth and Moon possibly representing remnants of an old binary system. Such a preliminary scenario is supported by similar ages obtained from WD's for the Galactic halo [1] and, independently, by means of 187Re-232Th-238U nuclear geochronometry [3, 4], together with recent observations extremely metal-poor stars from the cosmic dawn in the bulge of the Milky Way [8]. This might be further elucidated in the near future by Th/U cosmochronometry based upon a nuclear production ratio Th/U = 0.96 [9] and additionally by means of a newly developed nucleogeochronometric age dating method for stellar spectroscopy [9-11]. The model shall stimulate geochemical data interpretation from a different perspective, to constrain the evolution and differentiation of planetary or lunar crusts and mantles in general. [1] Fontaine et al. (2001), Public. Astron. Soc. of the Pacific 113, 409-435. [2] Roller (2015), Abstract T34B-0407, AGU Spring Meeting 2015. [3] Roller (2016), Goldschmidt Conf. Abstr. 26, 2642. [4] Roller (2015), Goldschmidt Conf. Abstr. 25, 2672. [5] Roller (2015), Geophys. Res. Abstr. 18, EGU2016-33. [6] Arevalo et al. (2010), Chem. Geol. 271, 70-85. [7] Roller (2015), Geophys. Res. Abstr. 17, EGU2015-2399. [8] Howes et al. (2015), Nature 527, 484-487. [9] Roller (2016), JPS Conf. Proc., Nuclei in the Cosmos (NIC XIV), Niigata, Japan, subm. (NICXIV-001); NICXIV Abstr. #1570244284. [10] Roller (2016), JPS Conf. Proc., Nuclei in the Cosmos (NIC XIV), Niigata, Japan, subm. (NICXIV-002); NICXIV Abstr. #1570244285. [11] Roller (2016), JPS Conf. Proc., Nuclei in the Cosmos (NIC XIV), Niigata, Japan, subm. (NICXIV-003); NICXIV Abstr. #1570244281.

Motor skill failure or flow-experience? Functional brain asymmetry and brain connectivity in elite and amateur table tennis players.

PubMed

Wolf, Sebastian; Brölz, Ellen; Keune, Philipp M; Wesa, Benjamin; Hautzinger, Martin; Birbaumer, Niels; Strehl, Ute

2015-02-01

Functional hemispheric asymmetry is assumed to constitute one underlying neurophysiological mechanism of flow-experience and skilled psycho-motor performance in table tennis athletes. We hypothesized that when initiating motor execution during motor imagery, elite table tennis players show higher right- than left-hemispheric temporal activity and stronger right temporal-premotor than left temporal-premotor theta coherence compared to amateurs. We additionally investigated, whether less pronounced left temporal cortical activity is associated with more world rank points and more flow-experience. To this aim, electroencephalographic data were recorded in 14 experts and 15 amateur table tennis players. Subjects watched videos of an opponent serving a ball and were instructed to imagine themselves responding with a specific table tennis stroke. Alpha asymmetry scores were calculated by subtracting left from right hemispheric 8-13 Hz alpha power. 4-7 Hz theta coherence was calculated between temporal (T3/T4) and premotor (Fz) cortex. Experts showed a significantly stronger shift towards lower relative left-temporal brain activity compared to amateurs and a significantly stronger right temporal-premotor coherence than amateurs. The shift towards lower relative left-temporal brain activity in experts was associated with more flow-experience and lower relative left temporal activity was correlated with more world rank points. The present findings suggest that skilled psycho-motor performance in elite table tennis players reflect less desynchronized brain activity at the left hemisphere and more coherent brain activity between fronto-temporal and premotor oscillations at the right hemisphere. This pattern probably reflect less interference of irrelevant communication of verbal-analytical with motor-control mechanisms which implies flow-experience and predict world rank in experts. Copyright © 2015 Elsevier B.V. All rights reserved.

Initial in vitro evaluation of a pediatric vortex-mixing membrane lung.

PubMed

Peacock, J A; Bellhouse, B J; Abel, K; Bellhouse, E L; Bellhouse, F H; Jeffree, M A; Sykes, M K; Gardaz, J P

1983-05-01

A new design for a pediatric membrane lung is described in this paper. The lung consists of eight blood compartments, each having six U-shaped blood channels, with microporous PTFE membranes supported on rigid plates in such a way that the membranes form furrowed blood channels. Two rolling diaphragm pumps are attached to the open ends of the U-shaped blood channels; these pumps are operated in antiphase. Mean flow is provided by a roller pump placed at the inlet end of the membrane lung. Pulsatile blood flow within the blood channels produces successive vortex formation and ejection, leading to good blood mixing and high efficiency in gas transport. The design of the rolling diaphragm piston pumps ensures that the blood prime volume is low (280 ml), and the grouping of the pumps at one end of the oxygenator allows the driving mechanism to be simple and compact. The relatively wide blood channels (minimum width 0.5 mm) and vortex mixing make priming the membrane lung particularly easy. The membrane area is 0.39 m2. Preliminary performance testing of the pediatric membrane lung was undertaken by pumping blood around a circuit containing a roller pump, the membrane lung, and a bubble oxygenator (to adjust the blood gases at the inlet to the membrane lung). In five such experiments it was shown that the membrane lung transferred 80 ml O2/min and 120 ml CO2/min at a blood flow rate of 1.5 L/min.

Development of high-speed rolling-element bearings. A historical and technical perspective

NASA Technical Reports Server (NTRS)

Zaretsky, E. V.

1982-01-01

Research on large-bore ball and roller bearings for aircraft engines is described. Tapered roller bearings and small-bore bearings are discussed. Temperature capabilities of rolling element bearings for aircraft engines have moved from 450 to 589 K (350 to 600 F) with increased reliability. High bearing speeds to 3 million DN can be achieved with a reliability exceeding that which was common in commercial aircraft. Capabilities of available bearing steels and lubricants were defined and established. Computer programs for the analysis and design of rolling element bearings were developed and experimentally verified. The reported work is a summary of NASA contributions to high performance engine and transmission bearing capabilities.

CALUTRONS

DOEpatents

Pierson, W.M.

1958-09-16

A vacuum tank is described for a calutron and the mounting means for the tank whereby the tank mav be convenlently positioned in the proper place between the poles of the magnet and there readily adjuated in height. A plurality of grooved guide wheels are mounted on adjustable levers attached to one side of the tank, along with a plurality of plain rollers mounted on adjuatable levers attached to the same side of the tank on the opposite edge. The grooved guide wheels and rollers cooperate with a guide track and runway, respectively, fer movement of the tank into and out of the magant gap, while the adjustable levers permit the accurate positioning of the tank between the magnet pole pieces.

DOE Office of Scientific and Technical Information (OSTI.GOV)

Guo, Yi; Keller, Jonathan; Zhang, Zhiwei

The planetary load sharing characteristics of wind turbine gearboxes supported by cylindrical roller bearings (CRBs) and preloaded tapered roller bearings (TRBs) when subjected to rotor moments are compared in this work. Planetary bearing loads were measured in field-representative dynamometer tests and compared to loads predicted by finite-element models. Load sharing was significantly improved with preloaded TRBs. In pure torque conditions, the upwind planet bearing loads in the gearbox with preloaded TRBs were a maximum of 1.14 compared to 1.47 in the gearbox with CRBs. Consequently, the predicted fatigue life of the complete set of planetary bearings for the gearbox withmore » preloaded TRBs is 3.5 times greater than that of the gearbox with CRBs.« less

Pendulum rides, rotations and the Coriolis effect

NASA Astrophysics Data System (ADS)

Pendrill, Ann-Marie; Modig, Conny

2018-07-01

An amusement park is full of examples that can be made into challenging problems for students, combining mathematical modelling with video analysis, as well as measurements in the rides. Traditional amusement ride related textbook problems include free-fall, circular motion, pendula and energy conservation in roller coasters, where the moving bodies are typically considered point-like. However, an amusement park can offer many more examples that are useful in physics and engineering education, many of them with strong mathematical content. This paper analyses forces on riders in a large rotating pendulum ride, where the Coriolis effect is sufficiently large to be visible in accelerometer data from the rides and leads to different ride experiences in different positions.

Low profile, high load vertical rolling positioning stage

DOEpatents

Shu, Deming; Barraza, Juan

1996-01-01

A stage or support platform assembly for use in a synchrotron accurately positions equipment to be used in the beam line of the synchrotron. The support platform assembly includes an outer housing in which is disposed a lifting mechanism having a lifting platform or stage at its upper extremity on which the equipment is mounted. A worm gear assembly is located in the housing and is adapted to raise and lower a lifting shaft that is fixed to the lifting platform by an anti-binding connection. The lifting platform is moved vertically as the lifting shaft is moved vertically. The anti-binding connection prevents the shaft from rotating with respect to the platform, but does permit slight canting of the shaft with respect to the lifting platform so as to eliminate binding and wear due to possible tolerance mismatches. In order to ensure that the lifting mechanism does not move in a horizontal direction as it is moved vertically, at least three linear roller bearing assemblies are arranged around the outer-periphery of the lifting mechanism. One of the linear roller bearing assemblies can be adjusted so that the roller bearings apply a loading force against the lifting mechanism. Alternatively, a cam mechanism can be used to provide such a loading force.

Electrostatic Potential Generated During Extracorporeal Pump Prime Circulation Before Cardiopulmonary Bypass Initiation

PubMed Central

Newton, Haley S.; Niles, Scott D.; Ploessl, James; Richenbacher, Wayne

2007-01-01

Abstract: The development of electrostatic potentials generated during cardiopulmonary bypass (CPB) procedures using polyvinylchloride (PVC) tubing in conjunction with roller pumps has been previously documented. The resulting damage from the electrostatic discharge (ESD) has been reported to affect gas transfer devices, but details of potential damage to electronic components commonly used during extracorporeal circulation have not been similarly described. The purpose of this study was to measure the ability of a triboelectric potential to be generated from a primed, circulating, adult CPB pump before the initiation of CPB. Two identical adult CPB circuits were assembled: one incorporating a roller pump and the second incorporating a centrifugal pump mechanism. Primed pumps were circulated (1–6 LPM), and evidence of generated triboelectric potentials was evaluated using a digital multimeter (Fluke 8062 A). The ESD generated from an adult CPB circuit using a roller head configuration elicited a charge in excess of 600 DC V. An identical circuit constructed with a centrifugal pump mechanism did not produce any measurable charge. Sensitive electrical components in the CPB hardware platform may be damaged by ESD potential spikes of this magnitude. Preventative measures, such as circuit charge dissipation, may reduce the potential for such damage when using PVC tubing. PMID:17486872

Insensitivity of compaction properties of brittle granules to size enlargement by roller compaction.

PubMed

Wu, Sy-Juen; Sun, Changquan 'Calvin'

2007-05-01

Pharmaceutical granules prepared by roller compaction often exhibit significant loss of tabletability, that is, reduction in tensile strength, when compared to virgin powder. This may be attributed to granule size enlargement for highly plastic materials, for example, microcrystalline cellulose. The sensitivity of powder compaction properties on granule size variations impacts the robustness of the dry granulation process. We hypothesize that such sensitivity of compaction properties on granule size is minimum for brittle materials because extensive fracture of brittle granules during compaction minimizes differences in initial granule size. We tested the hypothesis using three common brittle excipients. Results show that the fine (44-106 microm), medium (106-250 microm), and coarse (250-500 microm) granules exhibit essentially identical tabletability below a certain critical compaction pressure, 100, 140, and 100 MPa for spray-dried lactose monohydrate, anhydrous dibasic calcium phosphate, and mannitol, respectively. Above respective critical pressure, tabletability lines diverge with smaller granules exhibiting slightly higher tablet tensile strength at identical compaction conditions. Overall, tabletability of brittle granules is insensitive to granule size enlargement. The results provide a scientific basis to the common practice of incorporating brittle filler to a typical tablet formulation processed by roller compaction granulation. (c) 2007 Wiley-Liss, Inc. and the American Pharmacists Association.

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

PubMed

Saarinen, Tuomas; Antikainen, Osmo; Yliruusi, Jouko

2017-11-01

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.

Guild structure, diversity and succession of dung beetles associated with Indian elephant dung in South Western Ghats forests

PubMed Central

Sabu, Thomas K.; Vinod, K. V.; Vineesh, P. J.

2006-01-01

The diversity, guild structure and succession of dung beetles associated with Indian elephant dung is described in a deciduous forest site in Western Ghats, a hot spot of diversity in India. Dung beetles were collected using baited pitfall traps and from exposed dung pats in the forest at intervals of 1, 3, 5, 7, 15 and 21 days. Twenty-one dung beetle species belonging to the 3 major functional guilds were recorded. Abundance of dwellers was high compared to rollers deviating from earlier reports on the high abundance of rollers in the afrotropical regions. Dweller Drepanocerus setosus and tunneler Onthophagus bronzeus were the most abundant species. Dung pats aged 3–5 days attracted the highest abundance of dung beetles. Bray Curtis similarity index indicated low community similarity between different stages of succession. Species richness and abundance of tunnelers increased with dung age and decreasing moisture up to a threshold level, followed by a decrease. Rollers and dwellers did not show any significant relationship with dung moisture content. Further research is needed to estimate the dung beetle community associated with the dung pats of other mega herbivores as well as of elephant dung in other forests of the Western Ghats. PMID:19537983

Advanced gearbox technology

NASA Technical Reports Server (NTRS)

Anderson, N. E.; Cedoz, R. W.; Salama, E. E.; Wagner, D. A.

1987-01-01

An advanced 13,000 HP, counterrotating (CR) gearbox was designed and successfully tested to provide a technology base for future designs of geared propfan propulsion systems for both commercial and military aircraft. The advanced technology CR gearbox was designed for high efficiency, low weight, long life, and improved maintainability. The differential planetary CR gearbox features double helical gears, double row cylindrical roller bearings integral with planet gears, tapered roller prop support bearings, and a flexible ring gear and diaphragm to provide load sharing. A new Allison propfan back-to-back gearbox test facility was constructed. Extensive rotating and stationary instrumentation was used to measure temperature, strain, vibration, deflection and efficiency under representative flight operating conditions. The tests verified smooth, efficient gearbox operation. The highly-instrumented advanced CR gearbox was successfully tested to design speed and power (13,000 HP), and to a 115 percent overspeed condition. Measured CR gearbox efficiency was 99.3 percent at the design point based on heat loss to the oil. Tests demonstrated low vibration characteristics of double helical gearing, proper gear tooth load sharing, low stress levels, and the high load capacity of the prop tapered roller bearings. Applied external prop loads did not significantly affect gearbox temperature, vibration, or stress levels. Gearbox hardware was in excellent condition after the tests with no indication of distress.

Improved oil-off survivability of tapered roller bearings

NASA Technical Reports Server (NTRS)

Kreider, Gary E.; Lee, Peter W.

1987-01-01

The aim of this program is to improve the oil-off survivability of a tapered roller bearing when applied to a helicopter transmission, since the tapered bearing has shown a performance advantage in this application. However, the critical roller end-rib conjunction is vulnerable to damage in an oil-off condition. Three powdered metal materials were selected to use as the rib material for oil-off evaluation. These were: M2 steel to a 65% density, CBS 1000M 65% density, and CBS 1000M 75% density. The bearing styles tested were ribbed cone (inner race) and ribbed cup (outer race). Carburized solid CBS 600 was also used as a ribbed material for comparison of oil-off results. The tests were conducted at six speeds from 4000 rpm (0.26 million DN) through 37000 rpm (2.4 million DN).The ribbed cup style bearing achieved longer lives than the ribbed cone style. A standard bearing lasted only 10 minutes at 4000 rpm; however, the 30-min oil-off goal was achieved through 11000 rpm using the survivable ribbed cup bearing. The oil-off lives at 37000 rpm were less than 10 seconds. The grinding of the powder metal materials and surface preparation to achieve an open porosity is extremely critical to the oil-off performance of the powder metal component.

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

PubMed Central

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

An interoperability experiment for sharing hydrological rating tables

NASA Astrophysics Data System (ADS)

Lemon, D.; Taylor, P.; Sheahan, P.

2013-12-01

The increasing demand on freshwater resources is requiring authorities to produce more accurate and timely estimates of their available water. Calculation of continuous time-series of river discharge and storage volumes generally requires rating tables. These approximate relationships between two phenomena, such as river level and discharge, and allow us to produce continuous estimates of a phenomenon that may be impractical or impossible to measure directly. Standardised information models or access mechanisms for rating tables are required to support sharing and exchange of water flow data. An Interoperability Experiment (IE) is underway to test an information model that describes rating tables, the observations made to build these ratings, and river cross-section data. The IE is an initiative of the joint World Meteorological Organisation/Open Geospatial Consortium's Hydrology Domain Working Group (HydroDWG) and the model will be published as WaterML2.0 part 2. Interoperability Experiments (IEs) are low overhead, multiple member projects that are run under the OGC's interoperability program to test existing and emerging standards. The HydroDWG has previously run IEs to test early versions of OGC WaterML2.0 part 1 - timeseries. This IE is focussing on two key exchange scenarios: Sharing rating tables and gauging observations between water agencies. Through the use of standard OGC web services, rating tables and associated data will be made available from water agencies. The (Australian) Bureau of Meteorology will retrieve rating tables on-demand from water authorities, allowing the Bureau to run conversions of data within their own systems. Exposing rating tables and gaugings for online analysis and educational purposes. A web client will be developed to enable exploration and visualization of rating tables, gaugings and related metadata for monitoring points. The client gives a quick view into available rating tables, their periods of applicability and the standard deviation of observations against the relationship. An example of this client running can be seen at the link provided. The result of the IE will form the basis for the standardisation of WaterML2.0 part 2. The use of the standard will lead to increased transparency and accessibility of rating tables, while also improving general understanding of this important hydrological concept.

Near-infrared spectroscopic analysis of the breaking force of extended-release matrix tablets prepared by roller-compaction: influence of plasticizer levels and sintering temperature.

PubMed

Dave, Vivek S; Fahmy, Raafat M; Hoag, Stephen W

2015-06-01

The aim of this study was to investigate the feasibility of near-infrared (NIR) spectroscopy for the determination of the influence of sintering temperature and plasticizer levels on the breaking force of extended-release matrix tablets prepared via roller-compaction. Six formulations using theophylline as a model drug, Eudragit® RL PO or Eudragit® RS PO as a matrix former and three levels of TEC (triethyl citrate) as a plasticizer were prepared. The powder blend was roller compacted using a fixed roll-gap of 1.5 mm, feed screw speed to roller speed ratio of 5:1 and roll pressure of 4 MPa. The granules, after removing fines, were compacted into tablets on a Stokes B2 rotary tablet press at a compression force of 7 kN. The tablets were thermally treated at different temperatures (Room Temperature, 50, 75 and 100 °C) for 5 h. These tablets were scanned in reflectance mode in the wavelength range of 400-2500 nm and were evaluated for breaking force. Tablet breaking force significantly increased with increasing plasticizer levels and with increases in the sintering temperature. An increase in tablet hardness produced an upward shift (increase in absorbance) in the NIR spectra. The principle component analysis (PCA) of the spectra was able to distinguish samples with different plasticizer levels and sintering temperatures. In addition, a 9-factor partial least squares (PLS) regression model for tablets containing Eudragit® RL PO had an r(2) of 0.9797, a standard error of calibration of 0.6255 and a standard error of cross validation (SECV) of 0.7594. Similar analysis of tablets containing Eudragit® RS PO showed an r(2) of 0.9831, a standard error of calibration of 0.9711 and an SECV of 1.192.

Injuries and small-wheel skates.

PubMed

Orenstein, J B

1996-02-01

To determine the types of injuries sustained during the use of in-line skates and to compare them with injuries sustained during the use of roller skates and skateboards, which have similar riding mechanics; and to assess the protection afforded by wrist, elbow, and knee guards. The study population was a consecutive series of injured patients who presented to the emergency department of a Level 1 trauma center between May 1992 and October 1993. Of the 137 patients with skating injuries evaluated in the ED during the study period, 63 (46%) were in-line skaters, 36 (26%) were roller skaters, and 38 (28%) were skateboarders. Minor injuries (sprains, bruises, lacerations) were more common than fractures, and there was no statistical difference in the types of injury between skate groups (P=NS). The most common serious injury was fracture of the distal arm, which occurred in each of the three skater groups (43%, n=59). Of these patients 37% (n=21) required open or closed orthopedic reduction. More fractures of the distal forearm or elbow occurred among skaters who had not been wearing wrist guards (P=.013; risk ratio, 2.07; 95% confidence interval, 1.37 to 3.13). Only 25% of skaters used any protective equipment. In-line skaters owned and used protective equipment more often than did roller-skaters or skateboarders. Most injuries occurred while the patient was travelling in the street or on the sidewalk. Injuries occurred more commonly because the skater was going too fast (35%), because the skater struck an object in the pavement (20%), or because the skater was unable to brake (19%) than because of equipment failure (2%) or interference from motor vehicles (3%). Injuries sustained by in-line skaters were similar to those sustained by roller skaters and skateboarders. The risk of wrist or elbow fracture is greater when wrist guards are not worn.

Roller Massage: A Descriptive Survey of Allied Health Professionals.

PubMed

Cheatham, Scott W

2018-04-13

In sports medicine, the interprofessional care of athletes has become a frequent practice. This type of care often involves different interventions used among professionals. One common intervention prescribed is roller massage (RM) or self-myofascial release. The trends in the use of RM among allied health professionals is non-existent. The surveillance of such responses has not been documented. To survey and document responses in the knowledge, clinical application, and use of RM devices among allied health professionals in the United States. Cross-sectional descriptive survey study. A 20 question survey was sent to allied health professionals including physical therapists, athletic trainers, and fitness professionals. The survey covered topics such as demographics, beliefs about RM, preferred devices, exercise prescription, and client education. Results One thousand forty-two professionals (N=1042) completed the survey. Most respondents believed that RM decreases pain (82%) and increases mobility (76%). A high percentage use a foam roller in their practice (81%), recommend a full-size foam roller (49%), and believe the medium density (48%) is the most effective. A high proportion of respondents prescribe RM for injury treatment (69%) and for pre-and post-exercise (61%). They also recommend rolling daily for 30 seconds to 2 minutes per muscle group (33%) at a self-paced cadence (46%). A high percentage of respondents use patient reported outcomes (74%), joint ROM (49%), and movement-based testing (48%) to measure effects of RM. Eighty-seven percent use live instruction to educate clients and 88% believe there is a gap in the research. The results of this survey document responses in the use of RM among allied health professionals. The reported responses provide insight into how professionals are using RM as an intervention and the potential gaps between the research and professional practice. Future studies are needed to further validate these findings.

Rolling Bearing Life Prediction, Theory, and Application

NASA Technical Reports Server (NTRS)

Zaretsky, Erwin V.

2016-01-01

A tutorial is presented outlining the evolution, theory, and application of rolling-element bearing life prediction from that of A. Palmgren, 1924; W. Weibull, 1939; G. Lundberg and A. Palmgren, 1947 and 1952; E. Ioannides and T. Harris, 1985; and E. Zaretsky, 1987. Comparisons are made between these life models. The Ioannides-Harris model without a fatigue limit is identical to the Lundberg-Palmgren model. The Weibull model is similar to that of Zaretsky if the exponents are chosen to be identical. Both the load-life and Hertz stress-life relations of Weibull, Lundberg and Palmgren, and Ioannides and Harris reflect a strong dependence on the Weibull slope. The Zaretsky model decouples the dependence of the critical shear stress-life relation from the Weibull slope. This results in a nominal variation of the Hertz stress-life exponent. For 9th- and 8th-power Hertz stress-life exponents for ball and roller bearings, respectively, the Lundberg-Palmgren model best predicts life. However, for 12th- and 10th-power relations reflected by modern bearing steels, the Zaretsky model based on the Weibull equation is superior. Under the range of stresses examined, the use of a fatigue limit would suggest that (for most operating conditions under which a rolling-element bearing will operate) the bearing will not fail from classical rolling-element fatigue. Realistically, this is not the case. The use of a fatigue limit will significantly overpredict life over a range of normal operating Hertz stresses. (The use of ISO 281:2007 with a fatigue limit in these calculations would result in a bearing life approaching infinity.) Since the predicted lives of rolling-element bearings are high, the problem can become one of undersizing a bearing for a particular application. Rules had been developed to distinguish and compare predicted lives with those actually obtained. Based upon field and test results of 51 ball and roller bearing sets, 98 percent of these bearing sets had acceptable life results using the Lundberg- Palmgren equations with life adjustment factors to predict bearing life. That is, they had lives equal to or greater than that predicted. The Lundberg-Palmgren model was used to predict the life of a commercial turboprop gearbox. The life prediction was compared with the field lives of 64 gearboxes. From these results, the roller bearing lives exhibited a load-life exponent of 5.2, which correlated with the Zaretsky model. The use of the ANSI/ABMA and ISO standards load-life exponent of 10/3 to predict roller bearing life is not reflective of modern roller bearings and will underpredict bearing lives.

A numerical study of the laminar necklace vortex system and its effect on the wake for a circular cylinder

NASA Astrophysics Data System (ADS)

Kirkil, Gokhan; Constantinescu, George

2012-07-01

Large eddy simulation (LES) is used to investigate the structure of the laminar horseshoe vortex (HV) system and the dynamics of the necklace vortices as they fold around the base of a circular cylinder mounted on the flat bed of an open channel for Reynolds numbers defined with the cylinder diameter, D, smaller than 4460. The study concentrates on the analysis of the structure of the HV system in the periodic breakaway sub-regime, which is characterized by the formation of three main necklace vortices. Over one oscillation cycle of the previously observed breakaway sub-regime, the corner vortex and the primary vortex merge (amalgamate) and a developing vortex separates from the incoming laminar boundary layer (BL) to become the new primary vortex. Results show that while the classical breakaway sub-regime, in which one amalgamation event occurs per oscillation cycle, is present when the nondimensional displacement thickness of the incoming BL at the location of the cylinder is relatively large (δ*/D > 0.1), a new type of breakaway sub-regime is present for low values of δ*/D. This sub-regime, which we call the double-breakaway sub-regime, is characterized by the occurrence of two amalgamation events over one full oscillation cycle. LES results show that when the HV system is in one of the breakaway sub-regimes, the interactions between the highly coherent necklace vortices and the eddies shed inside the separated shear layers (SSLs) are very strong. For the relatively shallow flow conditions considered in this study (H/D ≅ 1, H is the channel depth), at times, the disturbances induced by the legs of the necklace vortices do not allow the SSLs on the two sides of the cylinder to interact in a way that allows the vorticity redistribution mechanism to lead to the formation of a new wake roller. As a result, the shedding of large-scale rollers in the turbulent wake is suppressed for relatively large periods of time. Simulation results show that the wake structure changes randomly between time intervals when large-scale rollers are forming and are convected in the wake (von Karman regime), and time intervals when the rollers do not form. When the wake is in the von Karman regime, the shedding frequency of the rollers is close to that observed for flow past infinitely long cylinders.

Belief in the paranormal and suggestion in the seance room.

PubMed

Wiseman, Richard; Greening, Emma; Smith, Matthew

2003-08-01

In Experiment 1, participants took part in a fake seance. An actor suggested that a table was levitating when, in fact, it remained stationary. After the seance, approximately one third of participants incorrectly reported that the table had moved. Results also showed a significant relationship between the reported movement of the table and belief in the paranormal, with a greater percentage of believers than disbelievers, reporting that the table had moved. Experiment 2 varied whether the suggestion was consistent, or inconsistent, with participants' belief in the paranormal. Results again showed that believers were more susceptible to suggestion than disbelievers, but only when the suggestion was consistent with their belief in the paranormal. Approximately one fifth of participants believed that the fake seances contained genuine paranormal phenomena.

Controlling Force and Depth in Friction Stir Welding

NASA Technical Reports Server (NTRS)

Adams, Glynn; Loftus, Zachary; McCormac, Nathan; Venable, Richard

2005-01-01

Feedback control of the penetration force applied to a pin tool in friction stir welding has been found to be a robust and reliable means for controlling the depth of penetration of the tool. This discovery has made it possible to simplify depth control and to weld with greater repeatability, even on workpieces with long weld joints. Prior to this discovery, depths of penetration in friction stir welding were controlled by hard-tooled roller assemblies or by depth actuators controlled by feedback from such external sensors as linear variable-differential transformers or laser-based devices. These means of control are limited: A hard-tooled roller assembly confines a pin tool to a preset depth that cannot be changed easily during the welding process. A measurement by an external sensor is only an indirect indicative of the depth of penetration, and computations to correlate such a measurement with a depth of penetration are vulnerable to error. The present force-feedback approach exploits the proportionality between the depth and the force of penetration Unlike a depth measurement taken by an external sensor, a force measurement can be direct because it can be taken by a sensor coupled directly to the pin tool. The reading can be processed through a modern electronic servo control system to control an actuator to keep the applied penetration force at the desired level. In comparison with the older depth-control methods described above, this method offers greater sensitivity to plasticizing of the workpiece metal and is less sensitive to process noise, resulting in a more consistent process. In an experiment, a tapered panel was friction stir welded while controlling the force of penetration according to this method. The figure is a plot of measurements taken during the experiment, showing that force was controlled with a variation of 200 lb (890 N), resulting in control of the depth of penetration with a variation of 0.004 in. (0.1 mm).

Scalable alignment of CdS nanowires based on efficient roll-on transfer technique.

PubMed

Yan, Shancheng; Shi, Yi; Xiao, Zhongdang; Wang, Junzhuan; Hu, Dong; Xul, Xin; Lu, Tao; Liu, Aili; Gao, Fan

2013-06-01

A roll-on transfer strategy is developed to enable large-scale and uniform assembly of CdS nanowires on various rigid and flexible substrate materials. In this method, the CdS nanowires were synthesized by the hydrothermal method. The dispersed CdS NWs could be firstly aligned and selectively deposited at the micro/nanochannels between aligned nanofibers on the surface of the donor roller as a result of evaporation-induced flow and capillary action, and then the directional and aligned transfer of the CdS NWs from the donor roller to a receiver substrate via roll-on transfer technique. Finally, a device structures consisting of the nanowire channel and two metal electrodes was fabricated. The electrical property of this device was observed.

Vibration analysis of paper machine's asymmetric tube roll supported by spherical roller bearings

NASA Astrophysics Data System (ADS)

Heikkinen, Janne E.; Ghalamchi, Behnam; Viitala, Raine; Sopanen, Jussi; Juhanko, Jari; Mikkola, Aki; Kuosmanen, Petri

2018-05-01

This paper presents a simulation method that is used to study subcritical vibrations of a tube roll in a paper machine. This study employs asymmetric 3D beam elements based on the Timoshenko beam theory. An asymmetric beam model accounts for varying stiffness and mass distributions. Additionally, a detailed rolling element bearing model defines the excitations arising from the set of spherical roller bearings at both ends of the rotor. The results obtained from the simulation model are compared against the results from the measurements. The results indicate that the waviness of the bearing rolling surfaces contributes significantly to the subcritical vibrations while the asymmetric properties of the tube roll have only a fractional effect on the studied vibrations.

Effect of Bearings on Vibration in Rotating Machinery

NASA Astrophysics Data System (ADS)

Daniel, Rudrapati Victor; Amit Siddhappa, Savale; Bhushan Gajanan, Savale; Vipin Philip, S.; Paul, P. Sam

2017-08-01

In rotary machines vibration is an inherent phenomenon which has the tendency to affect required performance. Amongst the different parameters that affect vibration, selection of appropriate bearing is the most critical component. In this work the effect of different types of bearing on vibration in rotary machines is studied and the magnitude of vibration produced by use of different set of bearings under the same condition of loads and rotational speeds were investigated. Bearings considered in this work were ball bearing, tapered roller bearing, thrust bearing and shaft material considered is of mild steel. From experimental result, it was noted that tapered roller bearing gives the highest amplitude of vibration among all the three bearings whereas the ball bearing gives least amplitude under similar operating conditions.

Performance tests with a 4.75 inch bore tapered-roller bearings at high speeds

NASA Technical Reports Server (NTRS)

Signer, H. R.; Pinel, S. I.

1977-01-01

The tapered-roller bearings were tested at speeds to 15,000 rpm which results in a cone-rib tangential velocity of 130 m/sec. (25,500 ft/min). Lubrication was applied either by jets or directly to the cone-rib, augmented with jets. Additional test parameters included thrust loads to 53,400 N (12,000 lbs), radial loads to 26,700 N (6,000 lbs), lubricant flow rates from 1.9 x 0.000 to 15.1 x 0.001 cubic meter/min. (0.5 to 4.0 gpm), and lubricant inlet temperatures of 350 K and 364 K (170 F and 195 F). Temperature distribution, separator speed, and drive-motor power demand were determined as functions of these test parameters.

Aerodynamics in the amusement park: interpreting sensor data for acceleration and rotation

NASA Astrophysics Data System (ADS)

Löfstrand, Marcus; Pendrill, Ann-Marie

2016-09-01

The sky roller ride depends on interaction with the air to create a rolling motion. In this paper, we analyse forces, torque and angular velocities during different parts of the ride, combining a theoretical analysis, with photos, videos as well as with accelerometer and gyroscopic data, that may be collected e.g. with a smartphone. For interpreting the result, it must be taken into account that the sensors and their coordinate system rotate together with the rider. The sky roller offers many examples for physics education, from simple circular motion, to acceleration and rotation involving several axes, as well as the relation between wing orientation, torque and angular velocities and using barometer pressure to determine the elevation gain.

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

USGS Publications Warehouse

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.

Response of anaerobic carbon cycling to water table manipulation in an Alaskan rich fen

Treesearch

E.S. Kane; M.R. Chivers; M.S. Turetsky; C.C. Treat; D.G. Petersen; M. Waldrop; J.W. Harden; A.D. McGuire

2013-01-01

To test the effects of altered hydrology on organic soil decomposition, we investigated CO2 and CH4 production potential of rich-fen peat (mean surface pH = 6.3) collected from a field water table manipulation experiment including control, raised and lowered water table treatments. Mean anaerobic CO2...

Family Reintegration Experiences of Soldiers with Mild Traumatic Brain Injury

DTIC Science & Technology

2014-02-26

depression scores in the spouse. Weak within-couple correlation were indicated on the other measures. Table 3 presents the Spearman correlation matrix...separately. Table 2: Spearman Correlation Coefficients for Couples Spouse MAT Spouse Depression Spouse...Anxiety Soldier MAT -0.06 Soldier Depression -0.61 Soldier Anxiety -0.12 Table 3: Spearman Correlation Coefficients for Soldiers and

Partnerships: The Path to Improving Crisis Communication

DTIC Science & Technology

2007-03-01

News Media Perceives Relationships with Public Safety.................32 Table 4. Public Safety SWOT Analysis ...opportunities and threats ( SWOT ) of the Seattle fire and police departments. The SWOT analysis is an assessment tool common to strategic planning for...requirements for training • Lack of strategic planning experience Table 4. Public Safety SWOT Analysis 46 Table 4 compares the strengths and

Shaker Table Experiments with Rare Earth Elements Sorption from Geothermal Brine

DOE Data Explorer

Gary Garland

2015-07-21

This dataset described shaker table experiments ran with sieved -50 +100 mesh media #1 in brine #1 that have 2ppm each of the 7 REE metals at different starting pH's of 3.5, 4.5, and 5.5. The experimental conditions are 2g media to 150mL of REE solution, at 70C.

Understanding drivers of peatland extracellular enzyme activity in the PEATcosm experiment: mixed evidence for enzymic latch hypothesis

Treesearch

Karl J. Romanowicz; Evan S. Kane; Lynette R. Potvin; Aleta L. Daniels; Randy Kolka; Erik A. Lilleskov

2015-01-01

Aims. Our objective was to assess the impacts of water table position and plant functional groups on peatland extracellular enzyme activity (EEA) framed within the context of the enzymic latch hypothesis. Methods. We utilized a full factorial experiment with 2 water table (WT) treatments (high and low) and 3 plant functional...

Agents Overcoming Resource Independent Scaling Threats (AORIST)

DTIC Science & Technology

2004-10-01

20 Table 8: Tilted Consumer Preferences Experiment (m=8, N=61, G=2, C=60, Mean over 13 experiments...probabilities. Non-uniform consumer preferences create a new potential for sub-optimal system performance and thus require an additional adaptive...distribu- tion of the capacities across the sup- plier population must match the non- uniform consumer preferences . The second plot in Table 8

Controlled laboratory experiments and modeling of vegetative filter strips with shallow water tables

NASA Astrophysics Data System (ADS)

Fox, Garey A.; Muñoz-Carpena, Rafael; Purvis, Rebecca A.

2018-01-01

Natural or planted vegetation at the edge of fields or adjacent to streams, also known as vegetative filter strips (VFS), are commonly used as an environmental mitigation practice for runoff pollution and agrochemical spray drift. The VFS position in lowlands near water bodies often implies the presence of a seasonal shallow water table (WT). In spite of its potential importance, there is limited experimental work that systematically studies the effect of shallow WTs on VFS efficacy. Previous research recently coupled a new physically based algorithm describing infiltration into soils bounded by a water table into the VFS numerical overland flow and transport model, VFSMOD, to simulate VFS dynamics under shallow WT conditions. In this study, we tested the performance of the model against laboratory mesoscale data under controlled conditions. A laboratory soil box (1.0 m wide, 2.0 m long, and 0.7 m deep) was used to simulate a VFS and quantify the influence of shallow WTs on runoff. Experiments included planted Bermuda grass on repacked silt loam and sandy loam soils. A series of experiments were performed including a free drainage case (no WT) and a static shallow water table (0.3-0.4 m below ground surface). For each soil type, this research first calibrated VFSMOD to the observed outflow hydrograph for the free drainage experiments to parameterize the soil hydraulic and vegetation parameters, and then evaluated the model based on outflow hydrographs for the shallow WT experiments. This research used several statistical metrics and a new approach based on hypothesis testing of the Nash-Sutcliffe model efficiency coefficient (NSE) to evaluate model performance. The new VFSMOD routines successfully simulated the outflow hydrographs under both free drainage and shallow WT conditions. Statistical metrics considered the model performance valid with greater than 99.5% probability across all scenarios. This research also simulated the shallow water table experiments with both free drainage and various water table depths to quantify the effect of assuming the former boundary condition. For these two soil types, shallow WTs within 1.0-1.2 m below the soil surface influenced infiltration. Existing models will suggest a more protective vegetative filter strip than what actually exists if shallow water table conditions are not considered.

Influence of Individual Experience and Flight Strips on Air Traffic Controller Memory/Situational Awareness

DTIC Science & Technology

1993-06-01

Aircraft 21 3-4 Mean Proportion Correct: Last Command Issued 22 3-5 Mean Proportion Correct: Last Altitude Change Issued 23 LIST OF TABLES Table Page 2-1...record altitude changes on strips. The same pattern of results was obtained. Participants with lower video-game experience showed poorer memory for...altitude changes than did those with higher experience, particularly when note- writing was not allowed. Flight strips may have been helpful to the group

The symmetric MSD encoder for one-step adder of ternary optical computer

NASA Astrophysics Data System (ADS)

Kai, Song; LiPing, Yan

2016-08-01

The symmetric Modified Signed-Digit (MSD) encoding is important for achieving the one-step MSD adder of Ternary Optical Computer (TOC). The paper described the symmetric MSD encoding algorithm in detail, and developed its truth table which has nine rows and nine columns. According to the truth table, the state table was developed, and the optical-path structure and circuit-implementation scheme of the symmetric MSD encoder (SME) for one-step adder of TOC were proposed. Finally, a series of experiments were designed and performed. The observed results of the experiments showed that the scheme to implement SME was correct, feasible and efficient.

The physiological and biomechanical differences between double poling and G3 skating in world class cross-country skiers.

PubMed

Sandbakk, Øyvind; Leirdal, Stig; Ettema, Gertjan

2015-03-01

The current study compared differences in cycle characteristics, energy expenditure and peak speed between double poling (DP) and G3 skating. Eight world class male sprint skiers performed a 5-min submaximal test at 16 km h(-1) and an incremental test to exhaustion at a 5% incline during treadmill roller skiing with two different techniques: DP where all propulsion comes from poling, and G3 skating where leg skating is added to each double poling movement. Video analyses determined cycle characteristics; respiratory parameters and blood lactate concentration determined the physiological responses. G3 skating resulted in 16% longer cycle lengths at 16% lower cycle rates, whereas oxygen uptake was independent of technique during submaximal roller skiing. The corresponding advantages for G3 skating during maximal roller skiing were reflected in 14% higher speed, 30% longer cycle length at 16% lower cycle rate and 11% higher peak oxygen uptake (all p < 0.05). Compared to DP approximately 14% higher speed was achieved when leg push-offs were added in G3 skating. This was done by major increases in cycle lengths at slightly lower cycle rates and a higher aerobic energy delivery. However, the oxygen uptake for a given submaximal speed was not affected by technique although higher cycle rate was used in DP.

Combining image processing and modeling to generate traces of beta-strands from cryo-EM density images of beta-barrels.

PubMed

Si, Dong; He, Jing

2014-01-01

Electron cryo-microscopy (Cryo-EM) technique produces 3-dimensional (3D) density images of proteins. When resolution of the images is not high enough to resolve the molecular details, it is challenging for image processing methods to enhance the molecular features. β-barrel is a particular structure feature that is formed by multiple β-strands in a barrel shape. There is no existing method to derive β-strands from the 3D image of a β-barrel at medium resolutions. We propose a new method, StrandRoller, to generate a small set of possible β-traces from the density images at medium resolutions of 5-10Å. StrandRoller has been tested using eleven β-barrel images simulated to 10Å resolution and one image isolated from the experimentally derived cryo-EM density image at 6.7Å resolution. StrandRoller was able to detect 81.84% of the β-strands with an overall 1.5Å 2-way distance between the detected and the observed β-traces, if the best of fifteen detections is considered. Our results suggest that it is possible to derive a small set of possible β-traces from the β-barrel cryo-EM image at medium resolutions even when no separation of the β-strands is visible in the images.

Roller compaction of hydrophilic extended release tablets-combined effects of processing variables and drug/matrix former particle size.

PubMed

Heiman, Johanna; Tajarobi, Farhad; Gururajan, Bindhumadhavan; Juppo, Anne; Abrahmsén-Alami, Susanna

2015-04-01

The present study shows that roller compaction (RC) can successfully be used as a granulation method to prepare hydroxypropyl methylcellulose (HPMC)-based extended release matrix tablets containing a high drug load, both for materials deforming mainly by fragmentation (paracetamol) as for those having mainly plastic deformation (ibuprofen). The combined effect of RC process variables and composition on the manufacturability of HPMC tablets was investigated. Standard wet granulation grade HPMC was compared with a larger particle size direct compressible HPMC grade. Higher roll pressure was found to result in larger paracetamol granules and narrower granule particle size distributions, especially for formulations containing smaller size HPMC. However, for ibuprofen, no clear effect of roll pressure was observed. High roll pressure also resulted in denser ribbon and less bypass fines during RC. Loss of compactibility was observed for granules compared to powder blends, which was found to be related to differences in granule porosity and morphology. Using the large-sized HPMC grade did in some cases result in lower tensile strength tablets but had the advantage to improve the powder flow into the roller compactor. This work also indicates that when the HPMC level lies near the percolation threshold, significant changes can occur in the drug release rate due to changes in other factors (raw material characteristics and processing).

Abrasion Resistance of Nano Silica Modified Roller Compacted Rubbercrete: Cantabro Loss Method and Response Surface Methodology Approach

NASA Astrophysics Data System (ADS)

Adamu, Musa; Mohammed, Bashar S.; Shafiq, Nasir

2018-04-01

Roller compacted concrete (RCC) when used for pavement is subjected to skidding/rubbing by wheels of moving vehicles, this causes pavement surface to wear out and abrade. Therefore, abrasion resistance is one of the most important properties of concern for RCC pavement. In this study, response surface methodology was used to design, evaluate and analyze the effect of partial replacement of fine aggregate with crumb rubber, and addition of nano silica on the abrasion resistance of roller compacted rubbercrete (RCR). RCR is the terminology used for RCC pavement where crumb rubber was used as partial replacement to fine aggregate. The Box-Behnken design method was used to develop the mixtures combinations using 10%, 20%, and 30% crumb rubber with 0%, 1%, and 2% nano silica. The Cantabro loss method was used to measure the abrasion resistance. The results showed that the abrasion resistance of RCR decreases with increase in crumb rubber content, and increases with increase in addition of nano silica. The analysis of variance shows that the model developed using response surface methodology (RSM) has a very good degree of correlation, and can be used to predict the abrasion resistance of RCR with a percentage error of 5.44%. The combination of 10.76% crumb rubber and 1.59% nano silica yielded the best combinations of RCR in terms of abrasion resistance of RCR.