Note: This page contains sample records for the topic affects torque production from Science.gov.
While these samples are representative of the content of Science.gov,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of Science.gov
to obtain the most current and comprehensive results.
Last update: August 15, 2014.
1

Torque  

NSDL National Science Digital Library

The simulation of a rotating wheel below shows the relationship between net torque on the wheel and its angular acceleration. The center of the wheel is fixed so that the net external force on the wheel remains zero.

Christian, Wolfgang; Belloni, Mario

2008-02-19

2

Production Experiences with the Cray-Enabled TORQUE Resource Manager  

SciTech Connect

High performance computing resources utilize batch systems to manage the user workload. Cray systems are uniquely different from typical clusters due to Cray s Application Level Placement Scheduler (ALPS). ALPS manages binary transfer, job launch and monitoring, and error handling. Batch systems require special support to integrate with ALPS using an XML protocol called BASIL. Previous versions of Adaptive Computing s TORQUE and Moab batch suite integrated with ALPS from within Moab, using PERL scripts to interface with BASIL. This would occasionally lead to problems when all the components would become unsynchronized. Version 4.1 of the TORQUE Resource Manager introduced new features that allow it to directly integrate with ALPS using BASIL. This paper describes production experiences at Oak Ridge National Laboratory using the new TORQUE software versions, as well as ongoing and future work to improve TORQUE.

Ezell, Matthew A [ORNL; Maxwell, Don E [ORNL; Beer, David [Adaptive Computing

2013-01-01

3

Moderate static stretching and torque production of the knee flexors.  

PubMed

Recent studies have suggested that acute static stretching (SS) decreases muscular strength and performance, particularly of the knee extensors. The purpose of this study was to investigate the effect of SS on peak concentric and eccentric torque production in the knee flexors. Subjects (13 women and 16 men) were tested for isokinetic concentric (CON) and eccentric (ECC) peak torque at 2 velocities (60 and 210 degrees x s(-1)) before and after a 3-minute knee flexor SS protocol. Subjects also underwent a control day in which the isokinetic pre- and posttests were separated by 10 minutes of sitting rather than stretching. A sit and reach test was administered on both days to assess changes in flexibility that occurred as a result of the stretching or control protocols. The change in flexibility was significantly greater after stretching than after sitting. Changes in peak torque were not significantly different between the stretching and control conditions for either velocity or contraction type. Compared with the control condition, SS of the knee flexors before maximal isokinetic testing does not lead to significantly diminished CON or ECC torque output at slow or fast contraction velocities. These data suggest that moderate SS does not impact the performance of all muscle groups. PMID:20145556

Winke, Molly R; Jones, Nathaniel B; Berger, Christopher G; Yates, James W

2010-03-01

4

Maximal Torque and Muscle Strength is Affected by Seat Distance from the Steering Wheel when Driving  

PubMed Central

[Purpose] This research analyzed how seat distance and gender affect maximal torque and muscle strength when driving to present base data for the optimal driving posture. [Subjects and Methods] The subjects were 27 college students in their 20's, 15 males and 12 females. After had been measured, the subjects sat in front of a steering wheel with the distance between the steering wheel and the seat set in turns. at 50, 70, and 90% their arm length, and the maximal torque and muscle strength were measured. [Results] Both the maximal torque and muscle strength were found to be greater in male subjects than female subjects whether they turned the steering wheel clockwise or counterclockwise. The difference was big enough to be statistically significant. Maximal torque was greatest when the seat distance was 50% of arm length, whether turning the steering wheel clockwise or counterclockwise. There were statistically significant differences in maximal torque between seat distances of 50 and 70% and 90% of the arm length. Muscle strength, in contrast, was found to be the greatest at a seat distance of 70% of arm length. [Conclusion] We conclude that greater torque can be obtained when the steering wheel is nearer the seat while greater muscle strength can be obtained when the seat distance from the steering wheel is 70% of the arm length.

Yoo, Kyung-Tae; An, Ho-Jung; Lee, Sun-Kyung; Choi, Jung-Hyun

2013-01-01

5

Muscle-damaging exercise affects isokinetic torque more at short muscle length.  

PubMed

The aim of this study was to investigate the differences in the length-dependent changes in quadriceps muscle torque during voluntary isometric and isokinetic contractions performed after severe muscle-damaging exercise. Thirteen physically active men (age = 23.8 ± 3.2 years, body weight = 77.2 ± 4.5 kg) performed stretch-shortening cycle (SSC) exercise comprising 100 drop jumps with 30-second intervals between each jump. Changes in the voluntary and electrically evoked torque in concentric and isometric conditions at different muscle lengths, muscle soreness, and plasma creatine kinase (CK) activity were assessed within 72 hours after SSC exercise. Isokinetic knee extension torque decreased significantly (p < 0.05) at all joint angles after SSC exercise. At 2 minutes and at 72 hours after SSC exercise, the changes in knee torque were significantly smaller at 80° (where 180° = full knee extension) than at 110-130°. At 2 minutes after SSC exercise, the optimal angle for isokinetic knee extension torque shifted by 9.5 ± 8.9° to a longer muscle length (p < 0.05). Electrically induced torque at low-frequency (20-Hz) stimulation decreased significantly more at a knee joint angle of 130° than at 90°. The subjects felt acute muscle pain and CK activity in the blood increased to 1,593.9 ± 536.2 IU·L?¹ within 72 hours after SSC exercise (p < 0.05). This study demonstrates that the effect of muscle-damaging exercise on isokinetic torque is greatest for contractions at short muscle lengths. These findings have practical importance because the movements in most physical activities are dynamic in nature, and the decrease in torque at various points in the range of motion during exercise might affect overall performance. PMID:21273917

Skurvydas, Albertas; Brazaitis, Marius; Kamandulis, Sigitas

2011-05-01

6

Acute effects of static stretching on maximal eccentric torque production in women.  

PubMed

The purpose of this study was to examine the acute effects of static stretching on peak torque (PT) and the joint angle at PT during maximal, voluntary, eccentric isokinetic muscle actions of the leg extensors at 60 and 180 degrees x s(-1) for the stretched and unstretched limbs in women. Thirteen women (mean age +/- SD = 20.8 +/- 0.8 yr; weight +/- SD = 63.3 +/- 9.5 kg; height +/- SD = 165.9 +/- 7.9 cm) volunteered to perform separate maximal, voluntary, eccentric isokinetic muscle actions of the leg extensors with the dominant and nondominant limbs on a Cybex 6000 dynamometer at 60 and 180 degrees x s(-1). PT (Nm) and the joint angle at PT (degrees) were recorded by the dynamometer software. Following the initial isokinetic assessments, the dominant leg extensors were stretched (mean stretching time +/- SD = 21.2 +/- 2.0 minutes) using 1 unassisted and 3 assisted static stretching exercises. After the stretching (4.3 +/- 1.4 minutes), the isokinetic assessments were repeated. The statistical analyses indicated no changes (p > 0.05) from pre- to poststretching for PT or the joint angle at PT. These results indicated that static stretching did not affect PT or the joint angle at PT of the leg extensors during maximal, voluntary, eccentric isokinetic muscle actions at 60 and 180 degrees x s(-1) in the stretched or unstretched limbs in women. In conjunction with previous studies, these findings suggested that static stretching may affect torque production during concentric, but not eccentric, muscle actions. PMID:16686563

Cramer, Joel T; Housh, Terry J; Coburn, Jared W; Beck, Travis W; Johnson, Glen O

2006-05-01

7

Intrasession and intersession reliability in maximal and explosive isometric torque production of the elbow flexors.  

PubMed

The purpose of this study was to assess intrasession and intersession reliability of maximal and explosive isometric torque production of the elbow flexors and its respective neuromuscular activation pattern. Subjects (13 men, age: 24.8 ± 3.1 years, height: 1.9 ± 0.1 m, body mass: 83.7 ± 12.7 kg; and 6 women, age: 26.5 ± 1.4 years, height: 1.7 ± 0.1 m, body mass: 62.7 ± 7.0 kg) were tested and retested 2-7 days later performing unilateral maximal isometric elbow flexions. Absolute (coefficient of variation [CV], test-retest variability [TRV], Bland-Altman plots with 95% limits of agreement) and relative reliability statistics (intraclass correlation coefficient) were calculated for various mechanical (i.e., maximal isometric torque, rate of torque development, impulse) and electromyographical measures (i.e., mean average voltage) at different time intervals relative to onset of torque (i.e., 30, 50, 100, 200, 300, 400, 100-200 ms). Intraclass correlation coefficient values were ? 0.61 for all mechanical and electromyographical measures and time intervals indicating good to excellent intrasession and intersession reliability. Bland-Altman plots confirmed these findings by showing that only 0-2 (? 13.3%) data points were beyond the limits of agreement. Regarding torque and electromyographic measures, CV (11.9-32.3%) and TRV (18.4-53.8%) values were high during the early intervals of torque development (? 100 ms) indicating high variability. During the later intervals (>100 ms), lower CV (i.e., 5.0-29.9%) and TRV values (i.e., 5.4-34.6%) were observed indicating lower variability. The present study revealed that neuromuscular performance during explosive torque production of the elbow flexors is reproducible in time intervals >100 ms after onset of isometric actions, whereas during earlier time intervals variability is high. PMID:24276297

Prieske, Olaf; Wick, Ditmar; Granacher, Urs

2014-06-01

8

Temperature effects on torque production and efficiency of PM motors using NdFeB magnets  

Microsoft Academic Search

Recent developments in high energy magnets have created widespread interest in the area of permanent magnet (PM) motors. The use of PM synchronous motors or brushless motors to replace conventional DC or induction type motors has not been as speedy as anticipated earlier. This paper deals with the temperature effects of PM motors using neodymium magnets on the torque production

Tomy Sebastian

1995-01-01

9

Larger plantar flexion torque variability implies less stable balance in the young: an association affected by knee position.  

PubMed

The present study examined the association between plantar flexion torque variability during isolated isometric contractions and during quiet bipedal standing. For plantar flexion torque measurements in quiet stance (QS), subjects stood still over a force plate. The mean plantar flexion torque level exerted by each subject in QS (divided by 2 to give the torque due to a single leg) served as the target torque level for right leg force-matching tasks in extended knee (KE) and flexed knee (KF) conditions. Muscle activation levels (EMG amplitudes) of the triceps surae and mean, standard deviation and coefficient of variation of plantar flexion torque were computed from signals acquired during periods with and without visual feedback. No significant correlations were found between EMG amplitudes and torque variability, regardless of the condition and muscle being analyzed. A significant correlation was found between torque variability in QS and KE, whereas no significant correlation was found between torque variability in QS and KF, regardless of vision availability. Therefore, torque variability measured in a controlled extended knee plantar flexion contraction is a predictor of torque variability in the anterior-posterior direction when the subjects are in quiet standing. In other words, larger plantar flexion torque variability in KE (but not in KF) implies less stable balance. The mechanisms underlying the findings above are probably associated with the similar proprioceptive feedback from the triceps surae in QS and KE and poorer proprioceptive feedback from the triceps surae in KF due to the slackening of the gastrocnemii. An additional putative mechanism includes the different torque contributions of each component of the triceps surae in the two knee angles. From a clinical and research standpoint, it would be advantageous to be able to estimate changes in balance ability by means of simple measurements of torque variability in a force matching task. PMID:24060221

Mello, Emanuele Moraes; Magalhães, Fernando Henrique; Kohn, André Fabio

2013-12-01

10

Ordinal logistic regression for affective product design  

Microsoft Academic Search

Affective product design, which focuses on customers¿ affective responses and aspirations, is arousing attention increasingly. This paper draws on ordinal logistic regression to deal with affective product design, mapping from designer domain to customer domain. It takes a designer¿s perspective and facilitates the handling of affective information and assists the designers to make trade-off decisions. Specifically, ten generic affective dimensions

F. Zhou; D. Wu; X. Yang; J. Jiao

2008-01-01

11

Geophysical Factors Affecting Plant Productivity.  

National Technical Information Service (NTIS)

A model for productivity is presented. It combines a model for photosynthesis with an energy budget approach to leaf energy balance. The photosynthesis model describes the rate of photosynthesis of a leaf as a function of leaf temperature, diffusive resis...

D. M. Gates H. B. Johnson C. S. Yocum P. W. Lommen

1969-01-01

12

Neuromuscular-skeletal constraints on the acquisition of skill in a discrete torque production task.  

PubMed

The organisation of the human neuromuscular-skeletal system allows an extremely wide variety of actions to be performed, often with great dexterity. Adaptations associated with skill acquisition occur at all levels of the neuromuscular-skeletal system although all neural adaptations are inevitably constrained by the organisation of the actuating apparatus (muscles and bones). We quantified the extent to which skill acquisition in an isometric task set is influenced by the mechanical properties of the muscles used to produce the required actions. Initial performance was greatly dependent upon the specific combination of torques required in each variant of the experimental task. Five consecutive days of practice improved the performance to a similar degree across eight actions despite differences in the torques required about the elbow and forearm. The proportional improvement in performance was also similar when the actions were performed at either 20 or 40% of participants' maximum voluntary torque capacity. The skill acquired during practice was successfully extrapolated to variants of the task requiring more torque than that required during practice. We conclude that while the extent to which skill can be acquired in isometric actions is independent of the specific combination of joint torques required for target acquisition, the nature of the kinetic adaptations leading to the performance improvement in isometric actions is influenced by the neural and mechanical properties of the actuating muscles. PMID:17006690

Shemmell, Jonathan; Forner, Matthew; Tathem, Benjamin; Tresilian, James R; Riek, Stephan; Barry, Benjamin K; Carson, Richard G

2006-11-01

13

Hyperphysics: Torque  

NSDL National Science Digital Library

This item is a short introduction to the concept of torque and how it influences the rotational motion of an object. It also contains links to more advanced materials involving torque calculation and direction, vector angular quantities, lever action, and angular acceleration. This item is part of a larger base of resources and instructional materials being continually developed by Rod Nave, Georgia State University.

Nave, Carl R.

2007-01-23

14

The effect of a four-week proprioceptive neuromuscular facilitation stretching program on isokinetic torque production.  

PubMed

Flexibility is widely accepted as an important component of fitness, yet flexibility training can be detrimental to muscle performance particularly where a high number of stretch cycles are performed. The purpose of this study was to investigate whether chronic proprioceptive neuromuscular facilitation (PNF) stretch training could successfully improve the knee flexion range of motion without having a detrimental effect on the peak isokinetic torque of the quadriceps. The minimum knee angle in flexion and the peak isokinetic quadriceps torque were measured at 120 and 270 degrees xs. Subjects then participated in a 4-week quadriceps flexibility training program consisting of 3 cycles of PNF stretching performed 3 times a week. The range of motion was recorded before and after the first stretching session of each week. At the end of the 4-week period, the peak isokinetic quadriceps torque and flexibility were again measured. The mean (SE) improvement in the knee flexion range of motion over the whole program was 9.2 degrees (1.45 degrees ), and typical gains after a single stretching session were around 3 degrees . Post hoc analysis showed that the pretraining session range of motion was significantly improved in week 4 compared with the pretraining session range of motion in weeks 1 and 2 (p < 0.05). There was no change (p = 0.9635) in the peak isokinetic torque produced at 120 degrees xs (week 1: 121.9 (4.6) N x m; week 2: 121.9 (5.2) N x m) or at 270 degrees xs (week 1: 88.1 (3.4) N x m; week 2: 88.6 (4.9) N x m). These findings suggest that it is possible to improve flexibility using 3 PNF stretch cycles performed 3 times a week without altering muscle isokinetic strength characteristics. PMID:19620921

Higgs, Fiona; Winter, Samantha L

2009-08-01

15

Torque teno sus virus 1 and 2 viral loads in postweaning multisystemic wasting syndrome (PMWS) and porcine dermatitis and nephropathy syndrome (PDNS) affected pigs.  

PubMed

Torque teno viruses (TTV) are small, non-enveloped viruses with a circular single-stranded DNA genome, which are considered non-pathogenic. However, TTVs have been eventually linked to human diseases. TTVs infecting pigs, Torque teno sus virus 1 (TTSuV1) and 2 (TTSuV2), have been recently associated to porcine circovirus diseases (PCVD). To get more insights into such potential disease association, the aim of this study was to quantify TTSuV1 and TTSuV2 viral loads in serum of pigs affected by two PCVDs, postweaning multisystemic wasting syndrome (PMWS) and porcine dermatitis and nephropathy syndrome (PDNS). Such study was carried out by means of a newly developed real-time quantitative PCR (qPCR) method. Both TTSuVs were highly prevalent among studied pigs. TTSuV2 viral loads were significantly higher in PMWS affected animals, further supporting the previously suggested association between TTSuV2 and PMWS. On the contrary, TTSuV1 prevalence and loads were not related with the studied PCVDs. PMID:21719215

Aramouni, M; Segalés, J; Sibila, M; Martin-Valls, G E; Nieto, D; Kekarainen, T

2011-12-15

16

How liability law affects medical productivity  

Microsoft Academic Search

Previous research suggests that “direct” reforms to the liability system—reforms designed to reduce the level of compensation to potential claimants—reduce medical expenditures without important consequences for patient health outcomes. We extend this research by identifying the mechanisms through which reforms affect the behavior of health care providers. Although we find that direct reforms improve medical productivity primarily by reducing malpractice

Daniel P. Kessler; Mark B. McClellan

2002-01-01

17

Doublet Electrical Stimulation Enhances Torque Production in People With Spinal Cord Injury  

PubMed Central

Background Muscle fatigue prevents repetitive use of paralyzed muscle after spinal cord injury (SCI). Objective This study compared the effects of hybrid patterns of muscle stimulation in individuals with acute and chronic SCI. Methods Individuals with chronic (n = 11) or acute paralysis (n = 3) underwent soleus muscle activation with a constant (CT) or doublet (DT) stimulation train before and at various times after a fatigue protocol. Results The chronically paralyzed soleus was highly fatigable with a fatigue index (FI) of 19% ± 6%, whereas the acutely paralyzed soleus was fatigue resistant (FI = 89% ± 8%). For the chronically paralyzed group, the DT protocol caused less than 5% improvement in peak and mean force relative to the CT protocol before fatigue; however, after fatigue the DT protocol caused an increase in peak and mean force (>10%), compared with the CT protocol (P < .05). As the chronically paralyzed muscle developed low-frequency fatigue, the DT protocol became more effective than the CT protocol (P < .05). The DT protocol increased the rate of torque development before fatigue (42% ± 78%), after fatigue (62% ± 52%), and during recovery (87% ± 54% to 101% ± 56%; P < .05). The acutely paralyzed group showed minimal change in peak and mean torque with the DT protocol. Conclusions Chronic reduced activity is associated with muscle adaptations (slow to fast) that render the muscle more amenable to force enhancement through doublet train activation after fatigue. These findings are applicable to patients using neuromuscular stimulation.

Chang, Ya-Ju; Shields, Richard K.

2014-01-01

18

Electric Field Driven Torque in ATP Synthase  

PubMed Central

FO-ATP synthase (FO) is a rotary motor that converts potential energy from ions, usually protons, moving from high- to low-potential sides of a membrane into torque and rotary motion. Here we propose a mechanism whereby electric fields emanating from the proton entry and exit channels act on asymmetric charge distributions in the c-ring, due to protonated and deprotonated sites, and drive it to rotate. The model predicts a scaling between time-averaged torque and proton motive force, which can be hindered by mutations that adversely affect the channels. The torque created by the c-ring of FO drives the ?-subunit to rotate within the ATP-producing complex (F1) overcoming, with the aid of thermal fluctuations, an opposing torque that rises and falls with angular position. Using the analogy with thermal Brownian motion of a particle in a tilted washboard potential, we compute ATP production rates vs. proton motive force. The latter shows a minimum, needed to drive ATP production, which scales inversely with the number of proton binding sites on the c-ring.

Miller, John H.; Rajapakshe, Kimal I.; Infante, Hans L.; Claycomb, James R.

2013-01-01

19

Tennis in hot and cool conditions decreases the rapid muscle torque production capacity of the knee extensors but not of the plantar flexors  

PubMed Central

Objectives To assess the time course of changes in rapid muscle force/torque production capacity and neuromuscular activity of lower limb muscles in response to prolonged (?2?h) match-play tennis under heat stress. Methods The rates of torque development (RTD) and electromyographic activity (EMG; ie, root mean square) rise were recorded from 0 to 30, –50, –100 and –200?ms during brief (3–5?s) explosive maximal isometric voluntary contractions (MVC) of the knee extensors (KE) and plantar flexors (PF), along with the peak RTD within the entirety of the torque-time curve. These values were recorded in 12 male tennis players before (prematch) and after (postmatch, 24 and 48?h) match-play in HOT (?37°C) and COOL (?22°C) conditions. Results The postmatch core temperature was greater in the HOT (?39.4°C) vs COOL (?38.7°C) condition (p<0.05). Reductions in KE RTD occurred within the 0–200?ms epoch after contraction onset postmatch and at 24?h, compared with prematch, independent of environmental conditions (p<0.05). A similar reduction in the KE peak RTD was also observed postmatch relative to prematch (p<0.05). No differences in KE RTD values were observed after normalisation to MVC torque. Furthermore, the rate of KE EMG activity rise remained unchanged. Conversely, the PF contractile RTD and rate of EMG activity rise were unaffected by the exercise or environmental conditions. Conclusions In the KE, a reduction in maximal torque production capacity following prolonged match-play tennis appears to account for the decrease in the rate of torque development, independent of environmental conditions, while remaining unchanged in the PF.

Girard, Olivier; Racinais, Sebastien; Periard, Julien D

2014-01-01

20

Torque teno sus virus 1 and 2 distribution in tissues of porcine circovirus type 2-systemic disease affected and age-matched healthy pigs.  

PubMed

The present work was aimed to investigate the torque teno sus virus 1 and 2 (TTSuV1 and 2) loads of different tissues of pigs affected by porcine circovirus type 2 (PCV2)-systemic disease (PCV2-SD) and healthy age-matched ones. A total of 20 pigs (10 healthy and 10 diagnosed as PCV2-SD) were chosen for the study. From each pig, a total of 7 tissues were analyzed, including lung, kidney, liver, ileum, bone marrow, and mesenteric and mediastinal lymph nodes. TTSuV 1 and 2 were quantified by means of species-specific real time quantitative PCR methods. Both TTSuVs were distributed systemically. Results showed the highest loads for TTSuV2 in tissues from diseased pigs. The highest TTSuV1 DNA load was found in bone marrow, lung, and liver, while it was in bone marrow, mediastinal lymph node and liver for TTSuV2. Bone marrow was the tissue with the highest viral DNA burden for both TTSuV species. Overall, statistically significant differences were observed in viral DNA load, with TTSuV2 showing higher loads than TTSuV1 (p<0.05). Also, tissues from PCVD-SD affected pigs showed higher TTSuV2 loads than tissues of the healthy group (p<0.05). It was concluded that both TTSuVs had a wide tissue distribution all over the body, with differential load comparing diseased versus healthy pigs. It is likely that other tissues not included in this study would also be infected by TTSuVs. PMID:23395293

Nieto, David; Kekarainen, Tuija; Aramouni, Mario; Segalés, Joaquim

2013-05-01

21

Establishing a relationship between maximum torque production of isolated joints to simulate EVA ratchet push-pull maneuver: A case study  

NASA Technical Reports Server (NTRS)

As manned exploration of space continues, analytical evaluation of human strength characteristics is critical. These extraterrestrial environments will spawn issues of human performance which will impact the designs of tools, work spaces, and space vehicles. Computer modeling is an effective method of correlating human biomechanical and anthropometric data with models of space structures and human work spaces. The aim of this study is to provide biomechanical data from isolated joints to be utilized in a computer modeling system for calculating torque resulting from any upper extremity motions: in this study, the ratchet wrench push-pull operation (a typical extravehicular activity task). Established here are mathematical relationships used to calculate maximum torque production of isolated upper extremity joints. These relationships are a function of joint angle and joint velocity.

Pandya, Abhilash; Maida, James; Hasson, Scott; Greenisen, Michael; Woolford, Barbara

1993-01-01

22

Affecting the System through Productive Evaluation.  

ERIC Educational Resources Information Center

The Educational Products Information Exchange Institute (EPIE) produces independently researched information on instructional material. The author believes textbook evaluation must be viewed in terms of the learner. The school, as a human system, may move toward effective expressive, productive interactions with internal and external environments…

Komoski, P. Kenneth

23

The effect of hand-grip stabilization on isokinetic torque at the knee.  

PubMed

Isokinetic dynamometers commonly measure muscle strength during conditioning and rehabilitation. Previous studies have shown that stabilization can affect isokinetic torque production. However, the effect of stabilization with hand-grip use has not been examined, and there are inconsistencies in the literature regarding its use. Fifteen men (mean age +/- SD = 24 +/- 3 years, height = 187 +/- 6 cm, mass = 84 +/- 10 kg) and 15 women (age = 25 +/- 4 years, height = 167 +/- 8 cm, mass = 62 +/- 6 kg) were tested on a Cybex 6000 dynamometer. Torque and joint angle signals, as well as quadriceps and hamstrings electromyographic (EMG) signals, were recorded during maximal knee flexion/extension at speeds of 60, 180, and 300 degrees x s(-1). Subjects performed the testing both with (stabilized) and without (nonstabilized with arms folded across the chest) hand-grip use. Repeated-measures analysis of variance (ANOVA) revealed a significant-motion (flexion, extension), X-condition (stabilized, non-stabilized) interaction in the data from the men in which hand-grip stabilization resulted in an 8.4% increase in knee extensor torque vs. a 0.2% increase in knee flexor torque. Stabilization did not significantly affect torque in women. The EMG analyses did not indicate a significant change in either agonist drive or antagonist cocontraction that accounted for the enhanced torque output with hand-grip use. This study found that hand-grip use enhanced knee extension maximal torque in men, but did not affect torque in women. The EMG data did not account for the changes in the torque data. Differences between men and women may have been due to mechanical factors and grip strength. These results indicate that hand-grip use needs to be considered when examining gender differences in knee strength and when studying knee flexion-extension ratios. PMID:11710668

Stumbo, T A; Merriam, S; Nies, K; Smith, A; Spurgeon, D; Weir, J P

2001-08-01

24

Variables Affecting the Production of Standard Biodiesel  

Microsoft Academic Search

Biodiesel is composed of fatty acid methyl esters, currently made from vegetable oils using basic catalysts. The oils must\\u000a be reacted two or three times with methanol, in the presence of sodium methoxide to make products which meet the ASTM and\\u000a European biodiesel standards. It is also believed that sodium hydroxide can never be used as the catalyst because it

Sonam Mahajan; Samir K. Konar; David G. B. Boocock

2007-01-01

25

Dynamics of Torque teno sus virus 1 (TTSuV1) and 2 (TTSuV2) DNA loads in serum of healthy and postweaning multisystemic wasting syndrome (PMWS) affected pigs.  

PubMed

Torque teno viruses (TTVs) are vertebrate infecting, small viruses with circular single stranded DNA, classified in the Anelloviridae family. In pigs, two different TTV species have been described so far, Torque teno sus virus 1 (TTSuV1) and 2 (TTSuV2). TTSuVs have lately been linked to postweaning multisystemic wasting syndrome (PMWS). In the present study, TTSuV1 and TTSuV2 prevalence and DNA loads in longitudinally collected serum samples of healthy and PMWS affected pigs from Spanish conventional, multi-site farms were analyzed. Serum samples were taken at 1, 3, 7, 11 and around 15 weeks of age (age of PMWS outbreak) and viral DNA loads determined by quantitative PCR. For both TTSuV species, percentage of viremic pigs increased progressively over time, with the highest prevalence in animals of about 15 weeks of age. TTSuV1 and TTSuV2 viral DNA loads in healthy and TTSuV1 loads in PMWS affected animals increased until 11 weeks of age declining afterwards. On the contrary, TTSuV2 DNA loads in PMWS affected pigs increased throughout the sampling period. It seems that TTSuV species differ in the in vivo infection dynamics in PMWS affected animals. PMID:21680113

Nieto, D; Aramouni, M; Grau-Roma, L; Segalés, J; Kekarainen, T

2011-09-28

26

Product design enhancement using apparent usability and affective quality  

Microsoft Academic Search

In this study, apparent usability and affective quality were integrated in a design framework called the Usability Perception and Emotion Enhancement Model (UPEEM). The UPEEM was validated using structural equation modeling (SEM). The methodology consists of four phases namely product selection, attribute identification, design alternative generation, and design alternative evaluation. The first stage involved the selection of a product that

Rosemary R. Seva; Katherine Grace T. Gosiaco; Ma. Crea Eurice D. Santos; Denise Mae L. Pangilinan

2011-01-01

27

An affective-cognitive framework of product ecosystem design  

Microsoft Academic Search

Companies have been constantly confronting the challenge of designing products for a totality of user experience, both affectively pleasurable with optimal intensity and cognitively convenient with appropriate intuition. It becomes more common that consumer products turn to be correlated with one another, in conjunction with services, use environments, along with many use context-related factors. This leads to a scenario of

F. Zhou; R. J. Jiao; Q. Xu; S. Chen; X. Qu; M. G. Helander

2009-01-01

28

Cytokine production in bipolar affective disorder patients under lithium treatment  

Microsoft Academic Search

Background: Our knowledge concerning immune functioning in bipolar affective disorder (BAD) is limited, while lithium's immunomodulatory effects seem multiple and conflicting. Our aim was to evaluate cytokine production and lithium's effect on it in BAD patients, using ELISPOT technique as a sensitive tool. Methods: Cytokine (IL-2, IL-6, IL-10 and IFN-?) production from isolated peripheral blood lymphocytes (PBLs) was evaluated (ELISPOT

Fotini Boufidou; Chryssoula Nikolaou; Basil Alevizos; Ioannis A. Liappas; George N. Christodoulou

2004-01-01

29

Muscle response to pneumatic hand tool torque reaction forces.  

PubMed

Surface electromyography was used for studying the effects of torque reaction force acting against the hand, on forearm muscle activity and grip force for five subjects operating right angle, air shut-off nutrunners. Four tools having increasing spindle torque were operated using short and long torque reaction times. Nutrunner spindle torque ranged between 30 Nm and 100 Nm. Short torque reaction time was considered 0.5 s while long torque reaction time was 2 s. Peak horizontal force was the greatest component of the reaction force acting against the hand and accounted for more than 97% of the peak resultant hand force. Peak hand force increased from 89 N for the smallest tool to 202 N for the largest tool. Forearm muscle rms EMG, scaled for grip force, indicated average flexor activity during the Torque-reaction phase was more than four times greater than the Pre-start and Post Shut-off phases, and two times greater than the Run-down phase. Flexor EMG activity during the Torque-reaction phase increased for increasing tool peak spindle torque. Average flexor rms EMG activity, scaled for grip force, during the Torque-reaction phase increased from 372 N for the 30 Nm nutrunner to 449 N for the 100 Nm nutrunner. Flexor rms EMG activity averaged during the Torque-reaction phase and scaled for grip force was 390 N for long torque reaction times and increased to 440 N for short torque reaction times. Flexor rms EMG integrated over the torque reaction phase was 839 Ns for long torque reaction times and decreased to 312 Ns for short torque reaction times. The average latency between tool spindle torque onset and peak initial flexor rms EMG for long torque reaction times was 294 ms which decreased to 161 ms for short torque reaction times. The average latency between peak tool spindle torque, just prior to tool shut-off, and peak final rms EMG for long torque reaction times was 97 ms for flexors and 188 ms for extensors, which decreased for short torque reaction times to 47 ms for flexors and 116 ms for extensors. The results suggest that right angle nutrunner torque reaction forces can affect extrinsic hand muscles in the forearm, and hence grip exertions, by way of a reflex response.(ABSTRACT TRUNCATED AT 400 WORDS) PMID:2776745

Radwin, R G; VanBergeijk, E; Armstrong, T J

1989-06-01

30

Variable Geometry Torque Converter.  

National Technical Information Service (NTIS)

Program objective was to design and evaluate a breadboard variable reactor system using the B-1 secondary power system torque converter. Results of the evaluation indicate that a variable reactor can be used in a small, high-speed torque converter to cont...

K. W. Benn G. L. Perrone

1978-01-01

31

Angular Acceleration without Torque?  

ERIC Educational Resources Information Center

Hardly. Just as Robert Johns qualitatively describes angular acceleration by an internal force in his article "Acceleration Without Force?" here we will extend the discussion to consider angular acceleration by an internal torque. As we will see, this internal torque is due to an internal force acting at a distance from an instantaneous center.

Kaufman, Richard D.

2012-01-01

32

Product design enhancement using apparent usability and affective quality.  

PubMed

In this study, apparent usability and affective quality were integrated in a design framework called the Usability Perception and Emotion Enhancement Model (UPEEM). The UPEEM was validated using structural equation modeling (SEM). The methodology consists of four phases namely product selection, attribute identification, design alternative generation, and design alternative evaluation. The first stage involved the selection of a product that highly involves the consumer. In the attribute identification stage, design elements of the product were identified. The possible values of these elements were also determined for use in the experimentation process. Design of experiments was used to identify how the attributes will be varied in the design alternative stage and which of the attributes significantly contribute to affective quality, apparent usability, and desirability in the design evaluation stage. Results suggest that product attributes related to form are relevant in eliciting intense affect and perception of usability in mobile phones especially those directly related to functionality and aesthetics. This study considered only four product attributes among so many due to the constraints of the research design employed. Attributes related to aesthetic perception of a product enhance apparent usability such as those related to dimensional ratios. PMID:20961531

Seva, Rosemary R; Gosiaco, Katherine Grace T; Santos, Ma Crea Eurice D; Pangilinan, Denise Mae L

2011-03-01

33

Managing Dialogue: How Information Availability Affects Collaborative Reference Production  

ERIC Educational Resources Information Center

Two experiments investigated how both shared and privileged knowledge affect reference production during dialogue. Dyads of participants jointly established routes for an imaginary person. Each participant was given a map featuring shared landmarks (i.e., they also appeared on the partner's map) and privileged landmarks (i.e., they did not appear…

Knutsen, Dominique; Le Bigot, Ludovic

2012-01-01

34

Torque correlation length and stochastic twist dynamics of DNA  

NASA Astrophysics Data System (ADS)

We introduce a short correlation length for torque in twisting-stiff biomolecules, which is necessary for the physical property that torque fluctuations be finite in amplitude. We develop a nonequilibrium theory of dynamics of DNA twisting which predicts two crossover time scales for temporal torque correlations in single-molecule experiments. Bending fluctuations can be included, and at linear order we find that they do not affect the twist dynamics. However, twist fluctuations affect bending, and we predict the spatial inhomogeneity of twist, torque, and buckling arising in nonequilibrium "rotor-bead" experiments.

Banigan, Edward J.; Marko, John F.

2014-06-01

35

Factors affecting productive efficiency in primary care clinics.  

PubMed

This study examines factors affecting the productive efficiency of primary care clinics. The empirical analysis uses a single-stage stochastic frontier regression model, in which factors affecting productive efficiency are specified as part of the inefficiency error component and estimated simultaneously with the production function. The study population includes primary care clinics in the US Military Health System from 1999 through 2003; the analytical data set is an unbalanced panel of 442 observations. The study's main results were that primary care clinics not associated with medical centres had significantly higher levels of productive efficiency than those associated with medical centres and that having proportionately more civilian staff (and thus less turnover) had a positive impact on productive efficiency. Due to their nature, these findings would be expected to also be applicable to the production of primary care in other settings. A key implication of the results is that improvements in productive efficiency should be a top priority, given the possibility for providing more primary care visits without increases in cost. PMID:18275665

Schmacker, Eric R; McKay, Niccie L

2008-02-01

36

Space Suit Joint Torque Testing  

NASA Technical Reports Server (NTRS)

In 2009 and early 2010, a test was performed to quantify the torque required to manipulate joints in several existing operational and prototype space suits in an effort to develop joint torque requirements appropriate for a new Constellation Program space suit system. The same test method was levied on the Constellation space suit contractors to verify that their suit design meets the requirements. However, because the original test was set up and conducted by a single test operator there was some question as to whether this method was repeatable enough to be considered a standard verification method for Constellation or other future space suits. In order to validate the method itself, a representative subset of the previous test was repeated, using the same information that would be available to space suit contractors, but set up and conducted by someone not familiar with the previous test. The resultant data was compared using graphical and statistical analysis and a variance in torque values for some of the tested joints was apparent. Potential variables that could have affected the data were identified and re-testing was conducted in an attempt to eliminate these variables. The results of the retest will be used to determine if further testing and modification is necessary before the method can be validated.

Valish, Dana J.

2011-01-01

37

Magnetostrictive torque sensor  

NASA Astrophysics Data System (ADS)

Magnetostrictive wire having a low surface-to-volume ratio established by a constant nonplanar cross-section is helically deformed into contact with a shaft under a stress maintaining the wire in fixed relation to the shaft surface. Magnetic anisotropy is imparted to the wire by twist thereof about its cross-sectional axis while the wire is being helically deformed into contact with the shaft surface to form a torque sensor through which accurate torque detection is achieved.

Savage, Howard T.; Clark, Arthur E.; Wun-Fogle, Marilyn; Kabacoff, Lawrence T.; Hernando, Antonio

1994-05-01

38

Magnetostrictive torque sensor  

NASA Astrophysics Data System (ADS)

Magnetostrictive wire having a low surface-to-volume ratio established by a constant non-planar cross-section, is helically deformed into contact with a shaft under a stress maintaining the wire in fixed relation to the shaft surface. Magnetic anisotropy is imparted to the wire by twist thereof about its cross-sectional axis while the wire is being helically deformed into contact with the shaft surface to form a torque sensor through which accurate torque detection is achieved.

Savage, Howard T.; Clark, Arthur E.; Wun-Fogie, Marilyn; Kabacoff, Lawrence T.; Herando, Antonio; Beihoff, Bruce

1989-06-01

39

Fabricated torque shaft  

DOEpatents

A fabricated torque shaft is provided that features a bolt-together design to allow vane schedule revisions with minimal hardware cost. The bolt-together design further facilitates on-site vane schedule revisions with parts that are comparatively small. The fabricated torque shaft also accommodates stage schedules that are different one from another in non-linear inter-relationships as well as non-linear schedules for a particular stage of vanes.

Mashey, Thomas Charles (Anderson, SC)

2002-01-01

40

How does burnout affect physician productivity? A systematic literature review  

PubMed Central

Background Interest in the well-being of physicians has increased because of their contributions to the healthcare system quality. There is growing recognition that physicians are exposed to workplace factors that increase the risk of work stress. Long-term exposure to high work stress can result in burnout. Reports from around the world suggest that about one-third to one-half of physicians experience burnout. Understanding the outcomes associated with burnout is critical to understanding its affects on the healthcare system. Productivity outcomes are among those that could have the most immediate effects on the healthcare system. This systematic literature review is one of the first to explore the evidence for the types of physician productivity outcomes associated with physician burnout. It answers the question, “How does burnout affect physician productivity?” Methods A systematic search was performed of: Medline Current, Medline in process, PsycInfo, Embase and Web of Science. The search period covered 2002 to 2012. The searches identified articles about practicing physicians working in civilian settings. Articles that primarily looked only at residents or medical students were excluded. Productivity was captured by hours worked, patients seen, sick leave, leaving the profession, retirement, workload and presenteeism. Studies also were excluded if: (1) the study sample was not comprised of at least 50% physicians, (2) the study did not examine the relationship between burnout and productivity or (3) a validated measure of burnout was not used. Results The search identified 870 unique citations; 5 met the inclusion/exclusion criteria. This review indicates that globally there is recognition of the potential impact of physician burnout on productivity. Productivity was examined using: number of sick leave days, work ability, intent to either continue practicing or change jobs. The majority of the studies indicate there is a negative relationship between burnout and productivity. However, there is variation depending on the type of productivity outcome examined. Conclusions There is evidence that burnout is associated with decreased productivity. However, this line of inquiry is still developing. A number of gaps are yet to be filled including understanding how to quantify the changes in productivity related to burnout.

2014-01-01

41

Core Material Parameter Analysis of Torque Characteristics of Small Motor  

NASA Astrophysics Data System (ADS)

This paper discusses the effect of manufacturing deterioration and permanent magnet conditions on cogging torque and iron loss in 12-pole small motors using 9-slot cores (20mm outer dia.). Manufacturing stress and strain increase 12n-th order cogging torques and iron loss, and smaller-clearance punching and larger-clearance clinching reduces iron loss althouogh they hardly affect cogging torque. The 9n-th order cogging torques are influenced a little by stress-relief annealing. The magnetization conditions of permanent magnet influences not only iron loss, but also cogging torque, which may be proportional to the square of magnet magnetization. However, cogging torques are hard to be induced at lower magnet magnetization.

Kaido, Chikara; Yamasaki, Jiro; Hanzawa, Kazufumi; Kaneko, Sachiko; Hashimoto, Toshio; Kimura, Toru; Shishido, Yuji

42

Detailed methodology for determining torque limits to maximize preload for high-strength threaded fasteners  

NASA Astrophysics Data System (ADS)

High-strength threaded fasteners are an amazing product of engineering, and one of the most common methods of making structural attachments. They are frequently used in structural joints because of two important features: such fasteners allow disassembly and reassembly of the joint, and they can generate high clamping loads called preload. To achieve the full benefit of threaded fasteners, the initial preload must be maximized. The benefits of high preload are well documented and include improved fatigue resistance, increased joint stiffness, and better resistance to vibration loosening. For joints in shear, preload resists relative motion, or slip, of the clamped members. Many factors, like elastic interactions and embedment, tend to lower the initial preload placed on the fastener. These factors provide additional motivation to maximize the initial preload. Also, in aerospace applications, maximized preloads help to achieve the full structural capacity from the fasteners, thereby minimizing weight. Of the available methods for controlling fastener preload, "torque control" is the most common. Unfortunately, determining the torque to maximize preload is problematic and greatly complicated by the large preload scatter generally seen with torque control. This dissertation presents a detailed methodology for generating torque limits to maximize preload for high-strength threaded fasteners. The methodology accounts for the large scatter in preload found with torque control, and therefore, addresses the statistical challenges of dealing with preload uncertainty. In developing this methodology, the probabilities of yielding the bolt during installation were calculated. To calculate these probabilities, the expected scatter in effective stress had to be determined. The scatter (or uncertainty) in the bolt's effective stress was shown to be less than the scatter in bolt preload. This result was observed in the torque-tension test data and also predicted by propagation of uncertainty theory. Prevailing torque is the torque required to overcome a locking feature in a fastener. The locking feature, typically added to the nut, helps to maintain preload and provide resistance to vibration loosening. Using this methodology, the prevailing torque of each locking nut is measured at installation to ensure that it is within specification. However, the measured prevailing torque is not added to the specified torque limit because its effect is already included in the torque limit value. Prevailing torque was shown to slightly reduce the achievable preload. Finally, the methodology was developed for specific fastener combinations; defined as a specific bolt type, nut, washer, and lubricant. Since friction is known to be the main influence on preload and preload scatter, testing specific fastener combinations limits the variables that affect friction. Once a torque limit is determined for a specific fastener combination, it can be applied to any joint using that combination. Taking this approach eliminates the need and the cost of lot-specific or joint-specific testing. A wide range of torque-tension fastener testing was conducted in support of this work. The results from this research should enable design engineers and structural analysts to produce more optimized bolted joints, leading to better structural designs.

Hissam, D. Andy

43

Ironless armature torque motor  

NASA Technical Reports Server (NTRS)

Four iron-less armature torque motors, four Hall device position sensor assemblies, and two test fixtures were fabricated. The design approach utilized samarium cobalt permanent magnets, a large airgap, and a three-phase winding in a stationary ironless armature. Hall devices were employed to sense rotor position. An ironless armature torque motor having an outer diameter of 4.25 inches was developed to produce a torque constant of 65 ounce-inches per ampere with a resistance of 20.5 ohms. The total weight, including structural elements, was 1.58 pounds. Test results indicated that all specifications were met except for generated voltage waveform. It is recommended that investigations be made concerning the generated voltage waveform to determine if it may be improved.

Fisher, R. L.

1972-01-01

44

Analysis of cogging torque considering tolerance of axial displacement on BLDC motor by using a stochastic simulation coupled with 3-D EMCN  

Microsoft Academic Search

In this paper, a tolerance analysis concerned with an axial displacement on a brushless dc motor is studied. The axial displacement occurring in productions of a brushless dc motor directly affects its torque ripple. Therefore, the tolerance analysis is very important to improve the robustness of its production. This work is accomplished by stochastic simulation in order to overcome disadvantages

Young-Kyoun Kim; Jeong-Jong Lee; Jung-Pyo Hong; Yoon Hur

2004-01-01

45

Factors affecting the estimate of primary production from space  

NASA Technical Reports Server (NTRS)

Remote sensing of primary production in the euphotic zone has been based mostly on visible-band and water-leaving radiance measured with the coastal zone color scanner. There are some robust, simple relationships for calculating integral production based on surface measurements, but they also require knowledge for photoadaptive parameters such as maximum photosynthesis which currently cannot be obtained from spave. A 17,000-station data set is used to show that space-based estimates of maximum photosynthesis could improve predictions of psi, the water column light utiliztion index, which is an important term in many primary productivity models. Temperature is also examined as a factor for predicting hydrographic structure and primary production. A simple model is used to relate temperature and maximum photosynthesis; the model incorporates (1) the positive relationship between maximum photosynthesis and temperature and (2) the strongly negative relationship between temperature and nitrate in the ocean (which directly affects maximum growth rates via nitrogen limitation). Since these two factors relate to carbon and nitrogen, 'balanced carbon/nitrogen assimilation' was calculated using the Redfield ratio, It is expected that the relationship between maximum balanced carbon assimilation versus temperature is concave-down, with the peak dependent on nitrate uptake kinetics, temperature-nitrate relationships,a nd the carbon chlorophyll ration. These predictions were compared with the sea truth data. The minimum turnover time for nitrate was also calculated using this approach. Lastly, sea surface temperature gradients were used to predict the slope of isotherms (a proxy for the slope of isopycnals in many waters). Sea truth data show that at size scales of several hundred kilometers, surface temperature gradients can provide information on the slope of isotherms in the top 200 m of the water column. This is directly relevant to the supply of nutrients into the surface mixed layer, which is useful for predicting integral biomass and primary production.

Balch, W. M.; Byrne, C. F.

1994-01-01

46

Detection of a porcine boca-like virus in combination with porcine circovirus type 2 genotypes and Torque teno sus virus in pigs from postweaning multisystemic wasting syndrome (PMWS)-affected and non-PMWS-affected farms in archival samples from Great Britain.  

PubMed

In this study we detail the detection and genetic analysis of a novel porcine boca-like virus (PBo-likeV) in archival sera and tissue samples from pigs from farms in Great Britain. We also investigate the distribution of porcine circovirus type 2 (PCV2) genotypes and Torque teno sus virus (TTSuV) genogroups 1 and 2 in combination with this novel PBo-likeV. PBo-likeV was detected in over 70% of all tissues investigated. Over 24% of all tissues recovered from PMWS-affected animals had all viruses present and 25% of tissues recovered from non-PMWS-affected pigs were positive for all 4 viruses. PMID:23578709

McMenamy, Michael J; McKillen, John; McNair, Irene; Duffy, Catherine; Blomström, Anne-Lie; Charreyre, Catherine; Welsh, Michael; Allan, Gordon

2013-06-28

47

An intelligent fuzzy regression approach for affective product design that captures nonlinearity and fuzziness  

Microsoft Academic Search

Affective product design aims at incorporating customers’ affective needs into design variables of a new product so as to optimise customers’ affective satisfaction. Faced with fierce competition in marketplaces, companies try to determine the settings in order to maximise customers’ affective satisfaction with products. To achieve this, a set of customer survey data is required in order to develop a

K. Y. Chan; C. K. Kwong; T. S. Dillon; K. Y. Fung

2011-01-01

48

Torque equilibrium attitudes for the Space Station  

NASA Technical Reports Server (NTRS)

All spacecraft orbiting in a low earth orbit (LEO) experience external torques due to environmental effects. Examples of these torques include those induced by aerodynamic, gravity-gradient, and solar forces. It is the gravity-gradient and aerodynamic torques that produce the greatest disturbances to the attitude of a spacecraft in LEO, and large asymmetric spacecraft, such as the space station, are affected to a greater degree because the magnitude of the torques will, in general, be larger in proportion to the moments of inertia. If left unchecked, these torques would cause the attitude of the space station to oscillate in a complex manner and the resulting motion would destroy the micro-gravity environment as well as prohibit the orbiter from docking. The application of control torques will maintain the proper attitude, but the controllers have limited momentum capacity. When any controller reaches its limit, propellant must then be used while the device is reset to a zero or negatively-biased momentum state. Consequently, the rate at which momentum is accumulated is a significant factor in the amount of propellant used and the frequency of resupply necessary to operate the station. A torque profile in which the area curve for a positive torque is not equal to the area under the curve for a negative torque is 'biased,' and the consequent momentum build-up about that axis is defined as secular momentum because it continues to grow with time. Conversely, when the areas are equal, the momentum is cyclic and bounded. A Torque Equilibrium Attitude (TEA) is thus defined as an attitude at which the external torques 'balance' each other as much as possible, and which will result in lower momentum growth in the controllers. Ideally, the positive and negative external moments experienced by a spacecraft at the TEA would exactly cancel each other out and small cyclic control torques would be required only for precise attitude control. Over time, the only momentum build-up in the controllers would be due to electro-mechanical losses within the device. However, the atmospheric torques are proportional to the density of the atmosphere and the density varies with the orbital position, time of day, time of year, and the solar cycle. In addition, there are unmodeled disturbances and uncertainties in the mass and inertias. Therefore, there is no constant attitude that will completely balance the environmental torques and the dynamic TEA cannot be solved in closed form. The objective of this research was to determine a method to calculate a dynamic TEA such that the rate of momentum build-up in the controllers would be minimized and to implement this method in the MATRIX(x) simulation software by Integrated Systems, Inc.

Thompson, Roger C.

1993-01-01

49

Reluctance torque analysis and reactance calculation of IPM for HEVs based on FEM  

Microsoft Academic Search

Rational utilization of reluctance torque can effectively improve torque performance and speed range in constant power region of interior permanent magnet(IPM) electric machines, thereby affecting dynamic performance of HEVs. This paper presents a reluctance torque analysis method on the basis of calculating the torque-power angle characteristic curve in advantage of FEM. Moreover, the direct(d) and quadrature(q) axis synchronous reactance is

Liwei Song; Daqian Jiang; Shumei Cui; Shan Sheng

2010-01-01

50

Torque, Cognitive Ability, and Schooling.  

ERIC Educational Resources Information Center

West African Hausan Children (N=110) aged 5-6 were administered a torque test and relationshps between the torque task and visual spatial tasks were analyzed. Findings supported the assumption that educational experience related to circling accounts for decrease in torque, or that the educational experiences have potential influence on cortical…

Csapo, Marg

1985-01-01

51

Floating-Pinion Torque Splitter  

NASA Technical Reports Server (NTRS)

Designed-in looseness at right locations helps to distribute torques more evenly. Gear-drive mechanism helps to apportion torques nearly equally along two parallel drive paths from input bevel gear to output bull gear. Mechanism of this type used as part of redundant drive train between engine and rotor of helicopter. Weighs less than comparably rated prior torque-splitting mechanisms.

Melles, Harold W.

1994-01-01

52

Manufacturing techniques - Split torque path helicopter transmission  

NASA Technical Reports Server (NTRS)

A description of the manufacturing techniques, capital equipment, tooling plan, and assembly methods necessary to manufacture the split torque path gearbox is presented. This transmission was designed and built for the advanced rotorcraft transmission program of the U.S. Army and NASA. Consideration is given to the engineering technology advancements along with a description of the integrated product development team process.

Mitchell, George D., Jr.

1991-01-01

53

Neither Helix in the Coiled Coil Region of the Axle of F1-ATPase Plays a Significant Role in Torque Production  

PubMed Central

F1-ATPase is an ATP-driven rotary molecular motor in which the central ?-subunit rotates inside the cylinder made of ?3?3 subunits. The amino and carboxy termini of the ?-subunit form the axle, an ?-helical coiled coil that deeply penetrates the stator cylinder. We previously truncated the axle step by step, starting with the longer carboxy terminus and then cutting both termini at the same levels, resulting in a slower yet considerably powerful rotation. Here we examine the role of each helix by truncating only the carboxy terminus by 25–40 amino-acid residues. Longer truncation impaired the stability of the motor complex severely: 40 deletions failed to yield rotating the complex. Up to 36 deletions, however, the mutants produced an apparent torque at nearly half of the wild-type torque, independent of truncation length. Time-averaged rotary speeds were low because of load-dependent stumbling at 120° intervals, even with saturating ATP. Comparison with our previous work indicates that half the normal torque is produced at the orifice of the stator. The very tip of the carboxy terminus adds the other half, whereas neither helix in the middle of the axle contributes much to torque generation and the rapid progress of catalysis. None of the residues of the entire axle played a specific decisive role in rotation.

Hossain, Mohammad Delawar; Furuike, Shou; Maki, Yasushi; Adachi, Kengo; Suzuki, Toshiharu; Kohori, Ayako; Itoh, Hiroyasu; Yoshida, Masasuke; Kinosita, Kazuhiko

2008-01-01

54

Importance of correcting isokinetic peak torque for the effect of gravity when calculating knee flexor to extensor muscle ratios.  

PubMed

The purpose of our investigation was to compare, for the hamstring and quadriceps femoris muscles, peak torque values uncorrected for gravity with the peak torque values corrected for gravity and to determine the effect of making this correction on the hamstring to quadriceps femoris muscle peak torque ratio at slow and fast isokinetic speeds. We measured peak torques isokinetically at 60 degrees/sec (slow) and 240 degrees/sec (fast) in 25 female university soccer players. The gravity effect torque (GET) is the torque resulting from the effect of gravity on the combined weight of the leg and dynamometer arm at the precise angle of extension and flexion peak torque. The GET was added to the measured quadriceps femoris muscle peak torque and subtracted from the hamstring muscle peak torque to yield gravity corrected values. Failure to consider GET greatly underestimated quadriceps femoris muscle torque and overestimated hamstring muscle torque and the ratio between these torques at both speeds. Whereas the uncorrected hamstring to quadriceps femoris muscle peak torque ratio increased as speeds went from 60 degrees/sec to 240 degrees/sec, the gravity corrected ratio significantly decreased. Clinicians must remember the importance of making the gravity correction in patients with reduced torque output where the gravitational torque is a greater percentage of the measured torque to ascertain correctly the relative strength of antagonists inversely affected by gravity. PMID:3941824

Fillyaw, M; Bevins, T; Fernandez, L

1986-01-01

55

Physclips: Rotation, torques, precession  

NSDL National Science Digital Library

This web page provides a multimedia introduction to rotation. It includes topics such as rotational kinetic energy, rotational kinematics, moment of inertia, torques, Newton's laws for rotation, and angular momentum. Short video clips, still images, graphs, and diagrams are integrated with text to promote understanding of important concepts. This tutorial is part of the PhysClip collection of web-based resources on introductory mechanics, electricity, and magnetism.

Wolfe, Joe

2009-06-19

56

Special-Purpose High-Torque Permanent-Magnet Motors  

NASA Technical Reports Server (NTRS)

Permanent-magnet brushless motors that must provide high commanded torques and satisfy unusual heat-removal requirement are developed. Intended for use as thrust-vector-control actuators in large rocket engines. Techniques and concepts used to design improved motors for special terrestrial applications. Conceptual motor design calls for use of rotor containing latest high-energy-product rare-earth permanent magnets so that motor produces required torque while drawing smallest possible currents from power supply. Torque generated by electromagnetic interaction between stator and permanent magnets in rotor when associated electronic circuits applied appropriately temporally and spatially phased currents to stator windings. Phase relationships needed to produce commanded torque computed in response to torque command and to electronically sensed angular position of rotor relative to stator.

Doane, George B., III

1995-01-01

57

Acute Whole-Body Vibration does not Facilitate Peak Torque and Stretch Reflex in Healthy Adults  

PubMed Central

The acute effect of whole-body vibration (WBV) training may enhance muscular performance via neural potentiation of the stretch reflex. The purpose of this study was to investigate if acute WBV exposure affects the stretch induced knee jerk reflex [onset latency and electromechanical delay (EMD)] and the isokinetic knee extensor peak torque performance. Twenty-two subjects were randomly assigned to the intervention or control group. The intervention group received WBV in a semi-squat position at 30° knee flexion with an amplitude of 0.69 mm, frequency of 45 Hz, and peak acceleration of 27.6 m/s2 for 3 minutes. The control group underwent the same semii-squatting position statically without exposure of WBV. Two-way mixed repeated measures analysis of variance revealed no significant group effects differences on reflex latency of rectus femoris (RF) and vastus lateralis (VL; p = 0.934 and 0.935, respectively) EMD of RF and VL (p = 0.474 and 0.551, respectively) and peak torque production (p = 0.483) measured before and after the WBV. The results of this study indicate that a single session of WBV exposure has no potentiation effect on the stretch induced reflex and peak torque performance in healthy young adults. Key Points There is no acute potentiation of stretch reflex right after whole body vibration. Acute whole body vibration does not improve mus-cle peak torque performance in healthy young adults.

Yeung, Ella W.; Lau, Cheuk C.; Kwong, Ada P.K.; Sze, Yan M.; Zhang, Wei Y.; Yeung, Simon S.

2014-01-01

58

Starting Torque of Single-Phase Flux-Switching Permanent Magnet Motors  

Microsoft Academic Search

In this paper, the starting torque of the 4\\/2 single-phase FSPM motor is investigated by finite element analysis, and validated experimentally. It is shown that the rotor pole-arc can significantly affect the electromagnetic torque and starting capability, since it also affects the amplitude and waveform of the cogging torque, and, therefore, the number and angular location of stable rotor rest

Y. Chen; Z. Zhu; D. Howe; Y. Ye

2006-01-01

59

Factors affecting regional changes in hardwood lumber production  

Microsoft Academic Search

Hardwood lumber production increased by nearly 1.8 billion board feet between 1986 and 1990 and decreased sharply in 1991. However. not all areas of the country experienced the same growth in hardwood lumber production during the 1980s. While lumber production in inland regions of the eastern United States and the west increased during the 1980s. lumber output in regions adjacent

William G. Luppold; Gilbert P. Dempsey

60

National Shipbuilding Research Program. 1997 Ship Production Symposium, Paper Number 7: Physiological Factors Affecting Quality and Safety in Production Environment.  

National Technical Information Service (NTIS)

Physiological and psychological influences affect the reliability of human performance, particularly in shift work production environments. These influences affect all personnel and include in part the quality and quantity of sleep achieved, the effects o...

V. Cantwell

1997-01-01

61

SMT Stencil Cleaning – A Decision that Could Affect Production  

Microsoft Academic Search

SMT stencil cleaning has traditionally been thought of as a ‘maintenance’ procedure with little or no impact on production. Today, CFC and VOC cleaning processes are being replaced because of environmental concerns, and fine-pitch and ultra fine-pitch assemblies are commonplace. These changes in cleaning processes and product specifications have shed new light on the importance of properly cleaning SMT screens

Richard S. Clouthier

1996-01-01

62

Momentum Confinement at Low Torque  

SciTech Connect

Momentum confinement was investigated on DIII-D as a function of applied neutral beam torque at constant normalized {beta}{sub N}, by varying the mix of co (parallel to the plasma current) and counter neutral beams. Under balanced neutral beam injection (i.e. zero total torque to the plasma), the plasma maintains a significant rotation in the co-direction. This 'intrinsic' rotation can be modeled as being due to an offset in the applied torque (i.e. an 'anomalous torque'). This anomalous torque appears to have a magnitude comparable to one co-neutral beam source. The presence of such an anomalous torque source must be taken into account to obtain meaningful quantities describing momentum transport, such as the global momentum confinement time and local diffusivities. Studies of the mechanical angular momentum in ELMing H-mode plasmas with elevated q{sub min} show that the momentum confinement time improves as the torque is reduced. In hybrid plasmas, the opposite effect is observed, namely that momentum confinement improves at high torque/rotation. The relative importance of E x B shearing between the two is modeled using GLF23 and may suggest a possible explanation.

Solomon, W M; Burrell, K H; deGrassie, J S; Budny, R; Groebner, R J; Heidbrink, W W; Kinsey, J E; Kramer, G J; Makowski, M A; Mikkelsen, D; Nazikian, R; Petty, C C; Politzer, P A; Scott, S D; Van Zeeland, M A; Zarnstorff, M C

2007-06-26

63

Torque control for electric motors  

NASA Technical Reports Server (NTRS)

Method for adjusting electric-motor torque output to accomodate various loads utilizes phase-lock loop to control relay connected to starting circuit. As load is imposed, motor slows down, and phase lock is lost. Phase-lock signal triggers relay to power starting coil and generate additional torque. Once phase lock is recoverd, relay restores starting circuit to its normal operating mode.

Bernard, C. A.

1980-01-01

64

Transpiration affects soil CO2 production in a dry grassland  

NASA Astrophysics Data System (ADS)

Although soil CO2 efflux can be highly variable on the diel time scale, it is often measured during daytime only. However, to get a full understanding of soil CO2 efflux and its impact on carbon cycle processes, looking at diurnal processes is crucial. Therefore, our aim was to investigate how diel variation in soil CO2 efflux from a dry, sandy grassland in Hungary depends on variations in potential drivers, such as gross primary production (GPP) and evapotranspiration (ET). In order to reach this goal, we combined measurements of CO2 and H2O fluxes by eddy covariance, soil chambers and soil CO2 gradient system. Surface CO2 fluxes were partitioned into the three CO2 production components originating from the three soil layers to clarify the timing and the source of the CO2 within the top 50 cm of the soil. CO2 production rates during the growing season were higher during nighttime than during daytime. This diel course was not only driven by soil temperature and soil moisture, but also by ET. This was shown by changes of ET causing a hysteresis loop in the diel response of CO2 production to soil temperature. CO2 production was coupled to soil temperature at night and during midday (12-14 h), when ET remained relatively constant. However, when ET was changing over time, CO2 production was decoupled from soil temperature. In order to disentangle these effects, we carried out time-lag analyses between CO2 production and efflux residuals after having subtracted the main effects of soil temperature and soil water content from measured CO2 fluxes. The results showed a strong negative correlation between ET rates and residuals of soil CO2 production, and a less strong, but still significantly time-lagged positive correlation between GPP and residuals of soil CO2 production. Thus, we could show that there is a rapid negative response of soil CO2 production rates to transpiration (suggesting CO2 transport in the xylem stream) and a delayed positive response to GPP, indicating the importance of newly synthesized non-structural carbohydrates for soil respiration. We conclude that the instant effect of soil temperature and transpiration in combination with the time-lagged effect of GPP governed the diel changes in soil CO2 production at our site. If measurements are carried out at night or during daytime only, then this can lead to considerable misinterpretations of CO2 production rates. Hence we recommend that estimates of respiration rates at a specific site should include both nocturnal and daytime processes.

Balogh, János; Fóti, Szilvia; Pintér, Krisztina; Burri, Susanne; Eugster, Werner; Papp, Marianna; Nagy, Zoltán

2014-05-01

65

Factors affecting quality of fresh-cut horticultural products  

Microsoft Academic Search

Fresh-cut products, also known as lightly or minimally processed products, are highly perishable because a large proportion of their surface area is without epidermis, the outer protective layer of tissue. Temperature, atmosphere, relative humidity and sanitation must be regulated to maintain quality of fresh-cuts. In the 0–10 °C range, Q10 of respiration rates ranged from 2.0 to 8.6 among various

Alley E. Watada; Nathanee P. Ko; Donna A. Minott

1996-01-01

66

Some factors affecting tannase production by Aspergillus niger Van Tieghem  

PubMed Central

One variable at a time procedure was used to evaluate the effect of qualitative variables on the production of tannase from Aspergillus niger Van Tieghem. These variables including: fermentation technique, agitation condition, tannins source, adding carbohydrates incorporation with tannic acid, nitrogen source type and divalent cations. Submerged fermentation under intermittent shaking gave the highest total tannase activity. Maximum extracellular tannase activity (305 units/50 mL) was attained in medium containing tannic acid as tannins source and sodium nitrate as nitrogen source at 30 °C for 96 h. All added carbohydrates showed significant adverse effects on the production of tannase. All tested divalent cations significantly decreased tannase production. Moreover, split plot design was carried out to study the effect of fermentation temperature and fermentation time on tannase production. The results indicated maximum tannase production (312.7 units/50 mL) at 35 °C for 96 h. In other words, increasing fermentation temperature from 30 °C to 35 °C resulted in increasing tannase production.

Aboubakr, Hamada A.; El-Sahn, Malak A.; El-Banna, Amr A.

2013-01-01

67

Thermal Spin Transfer Torques  

NASA Astrophysics Data System (ADS)

The coupling between spin and charge in electronic transport is studied in the field of spintronics. Heat currents are coupled to both charge and spin currents as well [1]. This extension of spintronics to what may be called ``spin caloritronics'' recently enjoys renewed attention [2]. The spin-transfer torque associated with electric currents can excite magnetizations in nanostructures, switching magnetic configuration in spin valves and move domain walls in magnetic wires when exceeding critical values of the order of 10^7Acm-2 [3]. Also heat currents transfer spin angular momentum [4], either intrinsically or via the thermoelectric generation of particle spin currents. We predict that temperature differences of the order of 100 K over typical metallic nanostructures cause effects equivalent to the critical charge current densities. In this talk I will give a brief review of various aspects of spin caloritronics with emphasis on thermal spin transfer torques. This work has been carried out in collaboration with Moosa Hatami, Qinfang Zhang, Paul Kelly, Hans Joakim Skadsem, Arne Brataas and Sadamichi Maekawa. [4pt] [1] M. Johnson and R.H. Silsbee, Phys. Rev. B 35, 4959 (1987).[0pt] [2] International Workshop on Spin Caloritronics, Lorentz Center of Leiden University, 9-13 February 2009, http://www.lorentzcenter.nl/lc/web/2009/323/info.php3?wsid=323[0pt] [3] D. C. Ralph and M. D. Stiles, J. Magn. Magn. Mater. 320, 1190 (2008).[0pt] [4] M. Hatami, G.E.W. Bauer, Q. Zhang, and P.J. Kelly, Phys. Rev. Lett. 99, 066603 (2007).

Bauer, Gerrit

2009-03-01

68

Factors affecting slip melting point of palm oil products  

Microsoft Academic Search

The effect of different factors affecting the slip melting point of palm oil has been evaluated. The most important factor\\u000a appears to be the difference in tempering temperatures. The influence of different tempering temperatures on slip point values\\u000a is, however, dependent on the nature of the sample. For hydrogenated oils and for some high-melting palm stearins, tempering\\u000a has no effect.

K. G. Berger; W. L. Siew; Flingoh C. H. OH

1982-01-01

69

Processes affecting greenhouse gas production in experimental boreal reservoirs  

NASA Astrophysics Data System (ADS)

Flooding land for water reservoir creation has many environmental impacts including the production of the greenhouse gases (GHG) carbon dioxide (CO2) and methane (CH4). To assess processes governing GHG emissions from the flooding of terrestrial carbon, three experimental reservoirs were constructed in upland boreal forest areas of differing carbon stores as part of the Flooded Upland Dynamics Experiment (FLUDEX). We calculated process-based GHG budgets for these reservoirs over 5 years following the onset of flooding. Stable isotopic budgets of carbon were necessary to separate community respiration (CR), which produces CO2, from net primary production (NPP), which consumes CO2, and to separate CH4 production from CH4 consumption via oxidation. NPP removed up to 44% of the CO2 produced from CR. CR and NPP exhibited different year-after-year trends. CH4 flux to the atmosphere increased about twofold over 3 years, yet isotopic budgets showed CH4 production in flooded soils increased nearly tenfold. CH4 oxidation near the flooded soil-water interface greatly decreased the CH4 flux from the water column to the atmosphere. Ebullition was the most important conduit of CH4 to the atmosphere after 3 years. Although CH4 production increased with time, the total GHG flux, in CO2 equivalents, declined. Contrary to expectations, neither CR nor total GHG fluxes were directly related to the quantity of organic carbon flooded. Instead, these reservoirs produced a strikingly similar amount of CO2 equivalents over 5 years.

Venkiteswaran, Jason J.; Schiff, Sherry L.; St. Louis, Vincent L.; Matthews, Cory J. D.; Boudreau, Natalie M.; Joyce, Elizabeth M.; Beaty, Kenneth G.; Bodaly, R. Andrew

2013-04-01

70

Temperature can interact with landscape factors to affect songbird productivity.  

PubMed

Increased temperatures and more extreme weather patterns associated with global climate change can interact with other factors that regulate animal populations, but many climate change studies do not incorporate other threats to wildlife in their analyses. We used 20 years of nest-monitoring data from study sites across a gradient of habitat fragmentation in Missouri, USA, to investigate the relative influence of weather variables (temperature and precipitation) and landscape factors (forest cover and edge density) on the number of young produced per nest attempt (i.e., productivity) for three species of songbirds. We detected a strong forest cover × temperature interaction for the Acadian Flycatcher (Empidonax virescens) on productivity. Greater forest cover resulted in greater productivity because of reduced brood parasitism and increased nest survival, whereas greater temperatures reduced productivity in highly forested landscapes because of increased nest predation but had no effect in less forested landscapes. The Indigo Bunting (Passerina cyanea) exhibited a similar pattern, albeit with a marginal forest cover × temperature interaction. By contrast, productivity of the Northern Cardinal (Cardinalis cardinalis) was not influenced by landscape effects or temperature. Our results highlight a potential difficulty of managing wildlife in response to global change such as habitat fragmentation and climate warming, as the habitat associated with the greatest productivity for flycatchers was also that most negatively influenced by high temperatures. The influence of high temperatures on nest predation (and therefore, nest predators) underscores the need to acknowledge the potential complexity of species' responses to climate change by incorporating a more thorough consideration of community ecology in the development of models of climate impacts on wildlife. PMID:23504884

Cox, W Andrew; Thompson, Frank R; Reidy, Jennifer L; Faaborg, John

2013-04-01

71

Important factors affecting trout production in the Black Sea Region, Turkey  

Microsoft Academic Search

ABSRACT: We determined the factors affecting trout production in the Black Sea Region, Turkey, on 55 trout farms. The factors affecting trout production were studied using the Cobb-Douglas production function. The explanatory variables in the model explained 99.4% of the variation in trout production. The partial percentage of the feed-use variable was 99%, whereas that of all other variables was

M. Bozo? lu; V. Ceyhan; H. Avni Cinemre; O. Kiliç

2007-01-01

72

Will Water Scarcity Affect Agricultural Production in China?  

Microsoft Academic Search

China has achieved impressive increases in grain production over the last 50 years due in large part to the expansion of irrigation, but many observers are beginning to question whether irrigated agriculture is sustainable in areas of China where water is relatively scarce. Despite competition from rapidly growing industry and increasingly wealthy consumers, farmers still receive over two-thirds of China's

Bryan Lohmar; Jinxia Wang

73

How lingering representations of abandoned context words affect speech production.  

PubMed

Four experiments tested whether and how initially planned but then abandoned speech can influence the production of a subsequent resumption. Participants named initial pictures, which were sometimes suddenly replaced by target pictures that were related in meaning or word form or were unrelated. They then had to stop and resume with the name of the target picture. Target picture naming latencies were measured separately for trials in which the initial speech was skipped, interrupted, or completed. Semantically related initial pictures helped the production of the target word, although the effect dissipated once the utterance of the initial picture name had been completed. In contrast, phonologically related initial pictures hindered the production of the target word, but only for trials in which the name of the initial picture had at least partly been uttered. This semantic facilitation and phonological interference did not depend on the time interval between the initial and target picture, which was either varied between 200 ms and 400 ms (Experiments 1-2) or was kept constant at 300 ms (Experiments 3-4). We discuss the implications of these results for models of speech self-monitoring and for models of problem-free word production. PMID:22673067

Tydgat, Ilse; Diependaele, Kevin; Hartsuiker, Robert J; Pickering, Martin J

2012-07-01

74

Bacterial biogas production in coastal systems affected by freshwater inputs  

Microsoft Academic Search

The concentrations of two greenhouse gases, nitrous oxide (N2O) and methane (CH4), and the bacterial processes involved in their production (nitrification and denitrification for N2O, and methanogenesis for CH4), were determined in surface waters of two coastal areas under the influence of freshwater inputs, on one part in the Gulf of Lions and the Rhone River plume, in northwestern Mediterranean

D. Marty; P Bonin; V Michotey; M Bianchi

2001-01-01

75

Lipases production by Bacillus circulans under mesophilic and osmophilic conditions. Factors affecting lipases production.  

PubMed

A facultative osmophilic bacterium able to produce lipases (isolated from bee honey) was identified as Bacillus circulans. Factors affecting lipases production by such isolate were studied. Dox's liquid medium supplied with 2 and/or 30% sucrose was used as a basal medium, under static culture condition, for such a purpose. Results have showed that the optimal sucrose concentration at which the isolate produced its maximal yield of lipases was 30% after an incubation period of 24 hours at 40 degrees C, and this was corresponding to an incubation period of 48 hours at 40 degrees C in presence of 2% sucrose. The optimal pH value was 7 in the first case while, 6.5 in the second. Furthermore production of extracellular lipases by such isolate was achieved in presence and absence of tributyrin as a carbon source instead of sucrose when supplied to Dox's liquid medium. Also the production of extracellular lipases by such isolate was not enhanced in presence of tributyrin as a supplement to Dox's liquid medium when supplied with 2 and/or 30% sucrose as carbon sources. This might suggest that the extracellular lipases of such isolate is constitutive in nature. PMID:6681018

Elwan, S H; el-Hoseiny, M M; Ammar, M S; Mostafa, S A

1983-01-01

76

40 CFR Table 2 to Subpart Xxxx of... - Emission Limits for Tire Cord Production Affected Sources  

Code of Federal Regulations, 2013 CFR

...Limits for Tire Cord Production Affected Sources 2 Table 2 to Subpart XXXX of Part...STANDARDS FOR HAZARDOUS AIR POLLUTANTS FOR SOURCE CATEGORIES (CONTINUED) National...Limits for Tire Cord Production Affected Sources As stated in § 63.5986, you...

2013-07-01

77

Space Suit Joint Torque Measurement Method Validation  

NASA Technical Reports Server (NTRS)

In 2009 and early 2010, a test method was developed and performed to quantify the torque required to manipulate joints in several existing operational and prototype space suits. This was done in an effort to develop joint torque requirements appropriate for a new Constellation Program space suit system. The same test method was levied on the Constellation space suit contractors to verify that their suit design met the requirements. However, because the original test was set up and conducted by a single test operator there was some question as to whether this method was repeatable enough to be considered a standard verification method for Constellation or other future development programs. In order to validate the method itself, a representative subset of the previous test was repeated, using the same information that would be available to space suit contractors, but set up and conducted by someone not familiar with the previous test. The resultant data was compared using graphical and statistical analysis; the results indicated a significant variance in values reported for a subset of the re-tested joints. Potential variables that could have affected the data were identified and a third round of testing was conducted in an attempt to eliminate and/or quantify the effects of these variables. The results of the third test effort will be used to determine whether or not the proposed joint torque methodology can be applied to future space suit development contracts.

Valish, Dana; Eversley, Karina

2012-01-01

78

Factors affecting the bioaccessibility of fluoride from seafood products.  

PubMed

Fluoride is considered important for health because of its beneficial effect on the prevention of dental caries and on bone development in the child population. However, excessive intake has negative effects. The main pathway for exposure is oral, through consumption of drinking water, and some food products. Therefore its bioaccessibility (quantity of the element solubilized during the digestive process) is a parameter to be considered when estimating the risk/benefit associated with this element. The aim of the present study was to evaluate the influence of the digestion phase, gastrointestinal digestion factors (pH, pepsin and bile salt concentrations) and the presence of cations on the bioaccessibility of fluoride from seafood products. The results show that the solubilization of fluoride takes place entirely during the gastric phase. Its bioaccessibility is strongly influenced by conditions that favor the formation of insoluble complexes of fluoride with other elements present in the matrix. The factors that are most influential in reducing its bioaccessibility are the increase in pH in the gastric phase, the presence of cations, especially in the intestinal phase, and a low concentration of bile salts. PMID:23747712

Rocha, R A; de la Fuente, B; Clemente, M J; Ruiz, A; Vélez, D; Devesa, V

2013-09-01

79

Heat Control via Torque Control in Friction Stir Welding  

NASA Technical Reports Server (NTRS)

In a proposed advance in friction stir welding, the torque exerted on the workpiece by the friction stir pin would be measured and controlled in an effort to measure and control the total heat input to the workpiece. The total heat input to the workpiece is an important parameter of any welding process (fusion or friction stir welding). In fusion welding, measurement and control of heat input is a difficult problem. However, in friction stir welding, the basic principle of operation affords the potential of a straightforward solution: Neglecting thermal losses through the pin and the spindle that supports it, the rate of heat input to the workpiece is the product of the torque and the speed of rotation of the friction stir weld pin and, hence, of the spindle. Therefore, if one acquires and suitably processes data on torque and rotation and controls the torque, the rotation, or both, one should be able to control the heat input into the workpiece. In conventional practice in friction stir welding, one uses feedback control of the spindle motor to maintain a constant speed of rotation. According to the proposal, one would not maintain a constant speed of rotation: Instead, one would use feedback control to maintain a constant torque and would measure the speed of rotation while allowing it to vary. The torque exerted on the workpiece would be estimated as the product of (1) the torque-multiplication ratio of the spindle belt and/or gear drive, (2) the force measured by a load cell mechanically coupled to the spindle motor, and (3) the moment arm of the load cell. Hence, the output of the load cell would be used as a feedback signal for controlling the torque (see figure).

Venable, Richard; Colligan, Kevin; Knapp, Alan

2004-01-01

80

Experimental study on torque control using harmonic drive built-in torque sensors  

Microsoft Academic Search

The authors have proposed a torque sensor which utilizes elasticity of harmonic drives. The characteristics of joint torque control were experimentally examined using this torque sensor. Three types of torque control laws were implemented with a one-link arm to find a control method which provides excellent friction reduction and dynamic response in joint torque. The experimental results of the joint

Minoru Hashimoto; Toshiaki Shimono; Ken-ichi Koreyeda; Hideho Tanaka; Y. Koyosawa; Hideki Hirabayashi

1992-01-01

81

Inward Torque and High-Friction Handles Can Reduce Required Muscle Efforts for Torque Generation  

Microsoft Academic Search

Objective: The effects of handle friction and torque direction on muscle activity and torque are empirically investigated using cylindrical handles. Background: A torque biomechanical model that considers contact force, friction, and torque direction was evaluated using different friction handles. Methods: Twelve adults exerted hand torque in opposite directions about the long axis of a cylinder covered with aluminum or rubber

Na Jin Seo; Thomas J. Armstrong; Don B. Chaffin; James A. Ashton-Miller

2008-01-01

82

Clinorotation affects morphology and ethylene production in soybean seedlings  

NASA Technical Reports Server (NTRS)

The microgravity environment of spaceflight influences growth, morphology and metabolism in etiolated germinating soybean. To determine if clinorotation will similarly impact these processes, we conducted ground-based studies in conjunction with two space experiment opportunities. Soybean (Glycine max [L.] Merr.) seeds were planted within BRIC (Biological Research In Canister) canisters and grown for seven days at 20 degrees C under clinorotation (1 rpm) conditions or in a stationary upright mode. Gas samples were taken daily and plants were harvested after seven days for measurement of growth and morphology. Compared to the stationary upright controls, plants exposed to clinorotation exhibited increased root length (125% greater) and fresh weight (42% greater), whereas shoot length and fresh weight decreased by 33% and 16% respectively. Plants grown under clinorotation produced twice as much ethylene as the stationary controls. Seedlings treated with triiodo benzoic acid (TIBA), an auxin transport inhibitor, under clinorotation produced 50% less ethylene than the untreated control subjected to the same gravity treatment, whereas a treatment with 2,4-D increased ethylene by five-fold in the clinorotated plants. These data suggest that slow clinorotation influences biomass partitioning and ethylene production in etiolated soybean plants.

Hilaire, E.; Peterson, B. V.; Guikema, J. A.; Brown, C. S.; Sager, J. C. (Principal Investigator)

1996-01-01

83

Long-term affected energy production of waste to energy technologies identified by use of energy system analysis  

Microsoft Academic Search

Affected energy production is often decisive for the outcome of consequential life-cycle assessments when comparing the potential environmental impact of products or services. Affected energy production is however difficult to determine. In this article the future long-term affected energy production is identified by use of energy system analysis. The focus is on different uses of waste for energy production. The

M. Muenster; P. Meibom

2010-01-01

84

Balancing Control for Dispersed Generators Considering Torsional Torque Suppression and AVR Performance for Synchronous Generators  

Microsoft Academic Search

Electric utility deregulation made possible for PPSs (Power Producer and Supplier) to entry the electricity market. PPSs are supposed to achieve 30-minute balancing control for stable supply of electric power. Meanwhile, load rejection and instantaneous voltage drop greatly affect turbine shafting, that is torsional torque oscillation. Therefore, PPSs have to consider reduction of torsional torque to prevent generator shaft damage.

Tomonobu Senjyu; Eitaro Omine; Daisuke Hayashi; Endusa Billy Muhando; Atsushi Yona; Toshihisa Funabashi

2008-01-01

85

Monitoring cutting tool operation and condition with a magnetoelastic rate of change of torque sensor  

SciTech Connect

Application of a magnetoelastic rate of change of torque sensor to monitor the condition of milling cutters and operating parameters is described. Cutting tools naturally degrade with use by wear, chipping, or fracture, and the efficiency and quality of the product are highly dependent on the tool condition. The theoretical analysis is compared to experimental data in detecting changes in torque during each cutting event, and the rate of change of torque signal is investigated for a variety of cutting tool conditions.

Garshelis, Ivan J.; Kari, Ryan J.; Tollens, Stijn P. L.; Cuseo, James M. [Magnova, Inc., Pittsfield, Massachusetts 01201 (United States) and MagCanica, Inc., San Diego, California 92117 (United States); MagCanica, Inc., San Diego, California 92117 (United States)

2008-04-01

86

A fundamental mechanism of legged locomotion with hip torque and leg damping.  

PubMed

New models and theories of legged locomotion are needed to better explain and predict the robustly stable legged locomotion of animals and some bio-inspired robots. In this paper we observe that a hip-torque and leg-damping mechanism is fundamental to many legged robots and some animals and determine its affect on locomotion dynamics. We discuss why this hip-torque-and-leg-damping mechanism is not so easily understood. We investigate how hip-torque and leg-damping affect the stability and robustness of locomotion using a mathematical model: First, we extend the canonical spring-loaded-inverted-pendulum model to include constant hip torque and leg damping proportional to leg length speed. Then, we calculate the stability and robustness of locomotion as a function of increasing levels of torque and damping, starting from zero-the energy conserving and marginally stable special case-to high levels of torque and damping. We find that the stabilizing effects of hip-torque and leg-damping occur in the context of the piecewise-continuous dynamics of legged locomotion, and so linear intuition does not apply. We discover that adding hip torque and leg damping changes the stability of legged locomotion in an unexpected way. When a small amount of torque and damping are added, legged locomotion is initially destabilized. As more torque and damping are added, legged locomotion turns stable and becomes increasingly more stable and more robust the more torque and damping are added. Also, stable locomotion becomes more probable over the biologically-relevant region of the parameter space, indicating greater prediction and explanatory capabilities of the model. These results provide a more clear understanding of the hip-torque-and-leg-damping mechanism of legged locomotion, and extend existing theory of legged locomotion towards a greater understanding of robustly stable locomotion. PMID:22989956

Shen, Z H; Seipel, J E

2012-12-01

87

Split torque transmission load sharing  

NASA Technical Reports Server (NTRS)

Split torque transmissions are attractive alternatives to conventional planetary designs for helicopter transmissions. The split torque designs can offer lighter weight and fewer parts but have not been used extensively for lack of experience, especially with obtaining proper load sharing. Two split torque designs that use different load sharing methods have been studied. Precise indexing and alignment of the geartrain to produce acceptable load sharing has been demonstrated. An elastomeric torque splitter that has large torsional compliance and damping produces even better load sharing while reducing dynamic transmission error and noise. However, the elastomeric torque splitter as now configured is not capable over the full range of operating conditions of a fielded system. A thrust balancing load sharing device was evaluated. Friction forces that oppose the motion of the balance mechanism are significant. A static analysis suggests increasing the helix angle of the input pinion of the thrust balancing design. Also, dynamic analysis of this design predicts good load sharing and significant torsional response to accumulative pitch errors of the gears.

Krantz, T. L.; Rashidi, M.; Kish, J. G.

1992-01-01

88

40 CFR Table 1 to Subpart Xxxx of... - Emission Limits for Tire Production Affected Sources  

Code of Federal Regulations, 2013 CFR

... National Emissions Standards for Hazardous Air Pollutants: Rubber Tire Manufacturing Pt. 63, Subpt. XXXX, Table 1 Table...exceed 0.024 grams per megagram (0.00005 pounds per ton) of rubber used at the tire production affected...

2013-07-01

89

40 CFR 1065.310 - Torque calibration.  

Code of Federal Regulations, 2010 CFR

...2009-07-01 2009-07-01 false Torque calibration. 1065.310 Section 1065.310...CONTROLS ENGINE-TESTING PROCEDURES Calibrations and Verifications Measurement of...Ambient Conditions § 1065.310 Torque calibration. (a) Scope and...

2009-07-01

90

14 CFR 27.361 - Engine torque.  

Code of Federal Regulations, 2012 CFR

...2014-01-01 false Engine torque. 27.361...Strength Requirements Flight Loads § 27.361 Engine torque. (a) For...three, and four, for engines with four, three...Sept. 2, 1988] Control Surface and System...

2014-01-01

91

14 CFR 29.361 - Engine torque.  

Code of Federal Regulations, 2013 CFR

...2014-01-01 false Engine torque. 29.361...Strength Requirements Flight Loads § 29.361 Engine torque. The limit...three, and four, for engines with four, three...Sept. 2, 1988] Control Surface and System...

2014-01-01

92

Intelligent torque sensing and robust torque control of harmonic drive under free-motion  

Microsoft Academic Search

A harmonic drive is a compact, light-weight and high-ratio torque transmission device which is used in many electrically actuated robot manipulators. In many robotic control strategies it is assumed that the actuator is an ideal torque source. However, converting harmonic drive systems to ideal torque sources is still a challenging control problem for researchers. In this paper the torque control

H. D. Taghirad; P. R. Belanger

1997-01-01

93

Spin Transfer torques in Antiferromagnets  

NASA Astrophysics Data System (ADS)

Spin Transfer Torque (STT) has attracted tremendously growing interest in the past two decades. Consisting on the transfer of spin angular momentum of a spin polarized current to local magnetic moments, the STT gives rise to a complex dynamics of the magnetization. Depending on the the structure, the STT shows a dominated In plane component for spin valves [1], whereas both components coexist for magnetic tunneling junctions (MTJ) [2]. For latter case the symmetry of the structure is considered to be decisive in identifying the nature and behavior of the torque [3]. In the present study we are interested in magnetic structures where we substitute either one or both of the magnetic layers by antiferromagnets (AF). We use Non-equilibrium Green's function formalism applied on a tight-binding model to investigate the nature of the spin torque. We notice the presence of two types of torque exerted on (AF), a torque which tends to rotate the order parameter and another one that competes with the exchange interaction. We conclude by comparison with previous works [4-5].[4pt] [1] Xia, K., Kelly, P. J., Bauer, G. E. W., Brataas, A. & Turek, Phys. Rev. B 65, 220401 (2002). [2] Sankey, J. C. et al. Nature Phys. 4, 67--71 (2008). [3] A. Kalitsov. et al. and W. H. Butler, Phys. Rev. B 79, 174416 (2009). [4] A. S. N'uñez , R. A. Duine, Paul Haney, and A. H. MacDonald, Phys. Rev. B 73, 214426 (2006). [5] R. A. Duine et al., Phys. Rev. B 75, 014433 (2007).

Saidaoui, Hamed; Waintal, Xavier; Manchon, Aurelien

2013-03-01

94

Computerized Torque Control for Large dc Motors  

NASA Technical Reports Server (NTRS)

Speed and torque ranges in generator mode extended. System of shunt resistors, electronic switches, and pulse-width modulation controls torque exerted by large, three-phase, electronically commutated dc motor. Particularly useful for motor operating in generator mode because it extends operating range to low torque and high speed.

Willett, Richard M.; Carroll, Michael J.; Geiger, Ronald V.

1987-01-01

95

Radiative Torques: Analytical Model And Basic Properties  

NASA Astrophysics Data System (ADS)

We attempt to get a physical insight into grain alignment processes by studying basic properties of radiative torques (RATs). For this purpose we consider a simple toy model of a helical grain that reproduces well the basic features of RATs. The model grain consists of a reflecting spheroidal body with a reflecting mirror attached at an angle to it. Being very simple, the model allows analytical description of RATs that act upon it. We show a good correspondence of RATs obtained for this model and those of irregular grains calculated by DDSCAT. Our analysis of the role of different torque components for grain alignment reveals that one of the three RAT components does not affect the alignment, but induces only for grain precession. The other two components provide a generic alignment with grain long axes perpendicular to the light radiation, if the radiation dominates the grain precession, and perpendicular to magnetic field, otherwise. The latter coincides with the famous predictions of the Davis-Greenstein process, but our model does not invoke paramagnetic relaxation. In addition, we find that a substantial part of grains subjected to RATs gets aligned with low angular momentum, which testifies, that most of the grains in diffuse interstellar medium do not rotate fast, i.e. rotate with thermal or even sub-thermal velocities. For the radiation-dominated environments, we find that the alignment can take place on the time scale much shorter than the time of gaseous damping of grain rotation.

Hoang, Thiem; Lazarian, A.

2007-05-01

96

Quenched Slonczewski windmill in spin-torque vortex oscillators  

NASA Astrophysics Data System (ADS)

We present a combined analytical and numerical study on double-vortex spin-torque nano-oscillators and describe a mechanism that suppresses the windmill modes. The magnetization dynamics is dominated by the gyrotropic precession of the vortex in one of the ferromagnetic layers. In the other layer, the vortex gyration is strongly damped. The dominating layer for the magnetization dynamics is determined by the sign of the product between sample current and the chiralities. Measurements on Fe/Ag/Fe nanopillars support these findings. The results open up a new perspective for building high quality-factor spin-torque oscillators operating at selectable, well-separated frequency bands.

Sluka, V.; Kákay, A.; Deac, A. M.; Bürgler, D. E.; Hertel, R.; Schneider, C. M.

2012-12-01

97

Torque generation mechanism of ATP synthase  

NASA Astrophysics Data System (ADS)

ATP synthase is a rotary motor that produces adenosine triphosphate (ATP), the chemical currency of life. Our proposed electric field driven torque (EFT) model of FoF1-ATP synthase describes how torque, which scales with the number of c-ring proton binding sites, is generated by the proton motive force (pmf) across the mitochondrial inner membrane. When Fo is coupled to F1, the model predicts a critical pmf to drive ATP production. In order to fully understand how the electric field resulting from the pmf drives the c-ring to rotate, it is important to examine the charge distributions in the protonated c-ring and a-subunit containing the proton channels. Our calculations use a self-consistent field approach based on a refinement of reported structural data. The results reveal changes in pKa for key residues on the a-subunit and c-ring, as well as titration curves and protonation state energy diagrams. Health implications will be briefly discussed.

Miller, John; Maric, Sladjana; Scoppa, M.; Cheung, M.

2010-03-01

98

Demographic and Academic Factors Affecting Research Productivity at the University of KwaZulu-Natal  

ERIC Educational Resources Information Center

Research output affects both the strength and funding of universities. Accordingly university academic staff members are under pressure to be active and productive in research. Though all academics have research interest, all are not producing research output which is accredited by the Department of Education (DOE). We analyzed the demographic and…

North, D.; Zewotir, T.; Murray, M.

2011-01-01

99

Factors that Affect Student Motivation in a Dairy Products Elective Course  

ERIC Educational Resources Information Center

Student motivation is influenced by instructional approach. Motivation is a function of initiating and sustaining goal-directed behavior. The objective of this study was to identify factors (positive and negative) that affect motivation in a junior-level dairy products elective course. Student attitudes were surveyed each year half-way through the…

Ismail, Baraem; Hayes, Kirby

2005-01-01

100

Exploration of Lexical-Semantic Factors Affecting Stress Production in Derived Words  

ERIC Educational Resources Information Center

Purpose: This study examined whether lexical frequency, semantic knowledge, or sentence context affect children's production of primary stress in derived words with stress-changing suffixes (e.g., "-ity"). Method: Thirty children (M[subscript age] = 9;1 [years;months]) produced a limited set of high-frequency (HF) and low-frequency (LF) derived…

Jarmulowicz, Linda; Taran, Valentina L.

2007-01-01

101

Altering SARS Coronavirus Frameshift Efficiency Affects Genomic and Subgenomic RNA Production  

PubMed Central

In previous studies, differences in the amount of genomic and subgenomic RNA produced by coronaviruses with mutations in the programmed ribosomal frameshift signal of ORF1a/b were observed. It was not clear if these differences were due to changes in genomic sequence, the protein sequence or the frequency of frameshifting. Here, viruses with synonymous codon changes are shown to produce different ratios of genomic and subgenomic RNA. These findings demonstrate that the protein sequence is not the primary cause of altered genomic and subgenomic RNA production. The synonymous codon changes affect both the structure of the frameshift signal and frameshifting efficiency. Small differences in frameshifting efficiency result in dramatic differences in genomic RNA production and TCID50 suggesting that the frameshifting frequency must stay above a certain threshold for optimal virus production. The data suggest that either the RNA sequence or the ratio of viral proteins resulting from different levels of frameshifting affects viral replication.

Plant, Ewan P.; Sims, Amy C.; Baric, Ralph S.; Dinman, Jonathan D.; Taylor, Deborah R.

2013-01-01

102

Analysis of extrinsic and intrinsic factors affecting event related desynchronization production.  

PubMed

Recently there has been an increase in the number of stroke patients with motor paralysis. Appropriate re-afferent sensory feedback synchronized with a voluntary motor intention would be effective for promoting neural plasticity in the stroke rehabilitation. Therefore, BCI technology is considered to be a promising approach in the neuro-rehabilitation. To estimate human motor intention, an event-related desynchronization (ERD), a feature of electroencephalogram (EEG) evoked by motor execution or motor imagery is usually used. However, there exists various factors that affect ERD production, and its neural mechanism is still an open question. As a preliminary stage, we evaluate mutual effects of intrinsic (voluntary motor imagery) and extrinsic (visual and somatosensory stimuli) factors on the ERD production. Experimental results indicate that these three factors are not always additively interacting with each other and affecting the ERD production. PMID:23366957

Takata, Yohei; Kondo, Toshiyuki; Saeki, Midori; Izawa, Jun; Takeda, Kotaro; Otaka, Yohei; It, Koji

2012-01-01

103

Isokinetic elbow torque development in children.  

PubMed

The aim of this study was to examine age and gender differences in isokinetic eccentric (ECC) elbow flexion (EF) and extension (EE) torques in children. Thirty-seven children participated in a 3-year longitudinal study. The average age +/- SD at the first test occasion was 13.0 +/- 0.3 years. Isokinetic ECC EF and EE torques at 0.52 rad . s (-1), MRI determined muscle cross-sectional areas (CSAs), stature, and arm length were determined annually. Concentric (CON) EF and EE torques for the same children reported previously, enabled functional torque ratios (ECC antagonist/CON agonist) to be calculated [ ]. In contrast to isokinetic EF torques, ECC EE torques were not significantly higher than CON EE torques (across test occasions and for boys and girls). Functional torque ratios did not significantly differ with age or between boys and girls. Multilevel modelling was used to examine age and gender effects once differences in body/muscle size had been considered. ECC EF torque was relatively greater in girls following adjustment for size. These data contribute to the understanding of differences in upper body strength performance and injury propensity during growth and maturation, suggesting CON and ECC torque development are muscle and gender specific. PMID:18004682

Wood, L E; Dixon, S; Grant, C; Armstrong, N

2008-06-01

104

Isometric, Isotonic, and Isokinetic Torque Variations in Four Muscle Groups through a Range of Joint Motion.  

National Technical Information Service (NTIS)

This investigation described and examined variations in maximal torque production in knee extension, knee flexion, elbow extension, and elbow flexion through a range of joint motion. Subjects were young, healthy male (N = 16) and female (N = 15) soldiers....

J. J. Knapik J. E. Wright R. H. Mawdsley J. Braun

1981-01-01

105

A Design Decision-Making Support Model for Prioritizing Affective Qualities of Product  

Microsoft Academic Search

\\u000a Nowadays, the affective qualities elicited by the product design plays a crucial role in determining the likelihood of its\\u000a success in today’s increasingly competitive marketplace. To resolve the trade-offs dilemma in multiple-attribute optimization\\u000a of affective user satisfaction, a decision-making support model based on the two-dimensional quality model, the extended Kano\\u000a model, is presented in this study. The proposed model can

Chun-Chih Chen; Ming-Chuen Chuan

2011-01-01

106

Investigation of Motorcycle Steering Torque Components  

NASA Astrophysics Data System (ADS)

When driving along a circular path, the rider controls a motorcycle mainly by the steering torque. This work addresses an in-depth analysis of the steady state cornering and in particular the decomposition of the motorcycle steering torque in its main components, such as road-tyre forces, gyroscopic torques, centrifugal and gravity effects. A detailed and experimentally validated multibody model of the motorcycle is used herein to analyze the steering torque components at different speeds and lateral accelerations. First the road tests are compared with the numerical results for three different vehicles and then a numerical investigation is carried out to decompose the steering torque. Finally, the effect of longitudinal acceleration and deceleration on steering torque components is presented.

Cossalter, V.; Lot, R.; Massaro, M.; Peretto, M.

2011-10-01

107

Balancing Control for Dispersed Generators Considering Torsional Torque Suppression and AVR Performance for Synchronous Generators  

NASA Astrophysics Data System (ADS)

Electric utility deregulation made possible for PPSs (Power Producer and Supplier) to entry the electricity market. PPSs are supposed to achieve 30-minute balancing control for stable supply of electric power. Meanwhile, load rejection and instantaneous voltage drop greatly affect turbine shafting, that is torsional torque oscillation. Therefore, PPSs have to consider reduction of torsional torque to prevent generator shaft damage. This paper propose the control system which enables to achieve both 30-minute balancing control and reduction of torsional torque by using H? controller. The effectiveness of proposed controller will be verified by using MATLAB.

Senjyu, Tomonobu; Omine, Eitaro; Hayashi, Daisuke; Muhando, Endusa Billy; Yona, Atsushi; Funabashi, Toshihisa

108

Optical fibre Bragg sensor torque transducer  

NASA Astrophysics Data System (ADS)

The benefits of an Optical Torque Transducer (OTT) based on optical fibre Bragg sensors for applications in any environment prone to electro-magnetic and temperature influences are outlined. By using an optical Rotation Coupler (RC) the transducer avoids slip rings or telemetry systems. The OTT enables the measurement of both torque and temperature free from electro-magnetic interference (EMI) in situations conventionally very difficult to make these measurements. OTT torque measurements compare favorably with that of a dynamometer.

van Wyk, A. J.; Snyman, M. C. S.

2007-07-01

109

Peak torque occurrence in the range of motion during isokinetic extension and flexion of the knee.  

PubMed

The purpose of this study was to 1) assess the knee angles of hamstring and quadriceps peak torques at slow (60 degrees.sec-1) and moderate (180 degrees.sec-1) isokinetic velocities in healthy adult males (N = 143) and females (N = 106), 2) determine if velocity has an effect on these peak torque angles, and 3) determine if subject's age, sex, and muscle strength have an effect on the results. The Cybex II dynamometer was used to record the measurements. At 60 degrees.sec-1, the mean peak torque for the hamstrings occurred at 33 degrees for men and 37 degrees for women (p < 0.001) (0 degree = full extension). At 180 degrees.sec-1, the corresponding angles were 40 and 44 degrees (p < 0.01). In both groups the increase was 7 degrees (p < 0.001). At 60 degrees.sec-1, the peak torque angle of the quadriceps was 54 degrees in both groups. At 180 degrees.sec-1, the angle occurred significantly later in men (11 degrees later) and in women (10 degrees later) (p < 0.001 for both). Subject's age (18 to 40 years) did not affect the results. In female hamstrings, the knee angle of peak torque had a highly significant (p < 0.001) negative correlation to muscle strength; that is, in female hamstrings, the peak torque angles occurred later in the range of motion when muscle strength decreased. This possibly explained the difference observed between men and women in the peak torque angles of hamstrings. In conclusion, people involved in isokinetic testing of muscular performance should be aware that the peak torque occurs later in the range of motion with increasing angular velocity, especially when testing weak muscle groups. In high angular velocities this may become a problem since the limb may pass the optimal joint position for muscular performance, and the recorded peak torque may not represent the subject's maximal torque capacity. PMID:8300265

Kannus, P; Beynnon, B

1993-11-01

110

Torque limited drive for manual valves  

DOEpatents

The present invention is directed to a torque-limiting handwheel device for preventing manual valves from being damaged due to the application of excessive torque during the opening or closing operation of the valves. Torque can only be applied when ridges in the handwheel assembly engage in channels machined in the face of the baseplate. The amount of torque required for disengagement of the ridges from the channels is determined by the force exerted by various Bellville springs and the inclination of the side faces of the channels.

Elliott, Philip G. (Metropolis, IL); Underwood, Daniel E. (Paducah, KY)

1989-01-01

111

Influence of tumour carriage on the production of lymphokines affecting macrophage behaviour.  

PubMed Central

Normal and cyclophosphamide (Cy)-enhanced delayed-type hypersensitivity (DTH) reactions to sheep red blood cells (SRBC) were severely impaired in CD1 mice injected with 10(6) viable Landschütz ascites carcinoma (LAC) cells at the time of immunization. The tumour-induced suppression of DTH was accompanied by inhibition of splenic T-lymphocyte responses to antigen and mitogen. This was assessed by measuring lymphocyte transformation and the production of two lymphokines affecting macrophage behavior, i.e. lymphocyte-derived chemotactic factor (LDCF) and macrophage procoagulant-inducing factor (MPIF). Our results imply that impaired production/function of lymphokines affecting macrophage behaviour may play a key role in tumour-induced suppression of cell-mediated immunity and that this inhibition is independent of Cy-sensitive suppressor cells.

McIntosh, L C; Morrice, L M; Udagawa, Y; Thomson, A W

1986-01-01

112

Herbivore and Fungal Pathogen Exclusion Affects the Seed Production of Four Common Grassland Species  

PubMed Central

Insect herbivores and fungal pathogens can independently affect plant fitness, and may have interactive effects. However, few studies have experimentally quantified the joint effects of insects and fungal pathogens on seed production in non-agricultural populations. We examined the factorial effects of insect herbivore exclusion (via insecticide) and fungal pathogen exclusion (via fungicide) on the population-level seed production of four common graminoid species (Andropogon gerardii, Schizachyrium scoparium, Poa pratensis, and Carex siccata) over two growing seasons in Minnesota, USA. We detected no interactive effects of herbivores and pathogens on seed production. However, the seed production of all four species was affected by either insecticide or fungicide in at least one year of the study. Insecticide consistently doubled the seed production of the historically most common species in the North American tallgrass prairie, A. gerardii (big bluestem). This is the first report of insect removal increasing seed production in this species. Insecticide increased A. gerardii number of seeds per seed head in one year, and mass per seed in both years, suggesting that consumption of flowers and seed embryos contributed to the effect on seed production. One of the primary insect species consuming A. gerardii flowers and seed embryos was likely the Cecidomyiid midge, Contarinia wattsi. Effects on all other plant species varied among years. Herbivores and pathogens likely reduce the dispersal and colonization ability of plants when they reduce seed output. Therefore, impacts on seed production of competitive dominant species may help to explain their relatively poor colonization abilities. Reduced seed output by dominant graminoids may thereby promote coexistence with subdominant species through competition-colonization tradeoffs.

Dickson, Timothy L.; Mitchell, Charles E.

2010-01-01

113

Herbivore and fungal pathogen exclusion affects the seed production of four common grassland species.  

PubMed

Insect herbivores and fungal pathogens can independently affect plant fitness, and may have interactive effects. However, few studies have experimentally quantified the joint effects of insects and fungal pathogens on seed production in non-agricultural populations. We examined the factorial effects of insect herbivore exclusion (via insecticide) and fungal pathogen exclusion (via fungicide) on the population-level seed production of four common graminoid species (Andropogon gerardii, Schizachyrium scoparium, Poa pratensis, and Carex siccata) over two growing seasons in Minnesota, USA. We detected no interactive effects of herbivores and pathogens on seed production. However, the seed production of all four species was affected by either insecticide or fungicide in at least one year of the study. Insecticide consistently doubled the seed production of the historically most common species in the North American tallgrass prairie, A. gerardii (big bluestem). This is the first report of insect removal increasing seed production in this species. Insecticide increased A. gerardii number of seeds per seed head in one year, and mass per seed in both years, suggesting that consumption of flowers and seed embryos contributed to the effect on seed production. One of the primary insect species consuming A. gerardii flowers and seed embryos was likely the Cecidomyiid midge, Contarinia wattsi. Effects on all other plant species varied among years. Herbivores and pathogens likely reduce the dispersal and colonization ability of plants when they reduce seed output. Therefore, impacts on seed production of competitive dominant species may help to explain their relatively poor colonization abilities. Reduced seed output by dominant graminoids may thereby promote coexistence with subdominant species through competition-colonization tradeoffs. PMID:20711408

Dickson, Timothy L; Mitchell, Charles E

2010-01-01

114

Factors affecting production of COS and CS 2 in Leucaena and Mimosa species  

Microsoft Academic Search

Carbon disulfide (CS2) and carbonyl sulfide (COS) are colorless, foul-smelling, volatile sulfur compounds with biocidal properties. Some plants produce CS2 or COS or both. When used as an intercrop or forecrop, these plants may have agronomic potential in protecting other plants. Most of the factors which affect production of these plant-generated organic sulfides are unknown. We determined the effects of

Zhe Feng; Peter G. Hartel

1996-01-01

115

Factors affecting waterfowl breeding density and productivity estimates in the Northeast  

USGS Publications Warehouse

During 1977-79, information useful for making breeding pair and brood surveys was obtained while studying black duck (Anas rubripes) habitat selection and productivity in south-central Maine. Surveys should be initiated in relation to sunrise and sunset time. Morning versus evening counts, familiarity with the survey area, wetland dynamics of the study area, wetland surface water area, and allotment of relative survey effort are discussed as they affect the conduct and results of brood surveys.

Longcore, J.R.; Ringelman, J.K.

1980-01-01

116

Granulocyte Macrophage Colony-Stimulating Factor Deficiency Affects Vascular Elastin Production and Integrity of Elastic Lamellae  

Microsoft Academic Search

Background: Granulocyte macrophage colony-stimulating factor (GM-CSF) deficiency affects the production and fiber assembly\\/organization of the vascular collagenous matrix; structural alterations to the elastic system were observed. The present study elaborates the effect of GM-CSF deficiency on the vascular elastin system. Methods and Results: Histological examination of the aorta of GM-CSF-deficient mice revealed structurally altered elastic fibers. The elastic fiber area

Gabriele Weissen-Plenz; Heike Eschert; Wolfgang Völker; Jürgen R. Sindermann; Stefan Beissert; Horst Robenek; Hans H. Scheld; Günter Breithardt

2008-01-01

117

Torque control with nonlinear compensation for harmonic drive DC motors  

Microsoft Academic Search

By controlling the torsional angle of the torque sensing element without using the torque sensor output, a high stiffness torque control system for geared DC motors has been proposed. This torque control system is successful when the torque sensor and the harmonic drive gear are modeled as linear springs. This paper describes a drive system observer added to the previous

Kenji KANEKO; Toshiyuki MURAKAMI; Kouhei OHNISHI; Kiyoshi KOMORIYA

1994-01-01

118

Prediction of automotive engine power and torque using least squares support vector machines and Bayesian inference  

Microsoft Academic Search

Automotive engine power and torque are significantly affected with effective tune-up. Current practice of engine tune-up relies on the experience of the automotive engineer. The engine tune-up is usually done by trial-and-error method, and then the vehicle engine is run on the dynamometer to show the actual engine output power and torque. Obviously, the current practice costs a large amount

Chi-Man Vong; Pak-Kin Wong; Yi-Ping Li

2006-01-01

119

Ejs Torque Free Top Model  

NSDL National Science Digital Library

The Ejs Torque Free Top model displays the motion of a top, in both the space frame and body frame, with no net toque applied. The top has an initial angular speed in the x, y, and z directions. The moments of inertia in each direction, and the initial angular positions and angular speeds can be changed via textboxes. You can modify this simulation if you have Ejs installed by right-clicking within the plot and selecting âOpen Ejs Modelâ from the pop-up menu item. Ejs Torque Free Top model was created using the Easy Java Simulations (Ejs) modeling tool. It is distributed as a ready-to-run (compiled) Java archive. Double clicking the ejs_ehu_rigid_bodies_free.jar file will run the program if Java is installed. Ejs is a part of the Open Source Physics Project and is designed to make it easier to access, modify, and generate computer models. Additional Ejs models for rigid body dynamics are available. They can be found by searching ComPADRE for Open Source Physics, OSP, or Ejs.

Aguirregabiria, Juan

2008-08-18

120

Self-oscillation in spin torque oscillator stabilized by field-like torque  

NASA Astrophysics Data System (ADS)

The effect of the field-like torque on the self-oscillation of the magnetization in spin torque oscillator with a perpendicularly magnetized free layer was studied theoretically. A stable self-oscillation at zero field is excited for negative ? while the magnetization dynamics stops for ? = 0 or ? > 0, where ? is the ratio between the spin torque and the field-like torque. The reason why only the negative ? induces the self-oscillation was explained from the view point of the energy balance between the spin torque and the damping. The oscillation power and frequency for various ? were also studied by numerical simulation.

Taniguchi, Tomohiro; Tsunegi, Sumito; Kubota, Hitoshi; Imamura, Hiroshi

2014-04-01

121

Radiation Forces and Torques without Stress (Tensors)  

ERIC Educational Resources Information Center

To understand radiation forces and torques or to calculate them does not require invoking photon or electromagnetic field momentum transfer or stress tensors. According to continuum electromagnetic theory, forces and torques exerted by radiation are a consequence of electric and magnetic fields acting on charges and currents that the fields induce…

Bohren, Craig F.

2011-01-01

122

High torque bellows seal rotary drive  

NASA Technical Reports Server (NTRS)

Bellows seal rotary drive device was developed which allows high torque transmission through sealed compartments. Bearing friction which would normally be carried by sealing bellows in comparable devices is absorbed by universal-gimbal joint. It can be used to transmit high torque, low speed, rotary motion through sealed barriers to prevent contamination or escape of fluids.

Diaguila, A. J.; Macomber, J. W.; Adams, D. W.

1972-01-01

123

40 CFR 63.6004 - How do I demonstrate continuous compliance with the emission limits for tire production affected...  

Code of Federal Regulations, 2013 CFR

...emission limits for tire production affected sources? 63.6004 Section 63.6004 Protection...STANDARDS FOR HAZARDOUS AIR POLLUTANTS FOR SOURCE CATEGORIES (CONTINUED) National Emissions...Requirements for Tire Production Affected Sources § 63.6004 How do I...

2013-07-01

124

40 CFR Table 6 to Subpart Xxxx of... - Initial Compliance With the Emission Limits for Tire Production Affected Sources  

Code of Federal Regulations, 2013 CFR

...Emission Limits for Tire Production Affected Sources 6 Table 6 to Subpart XXXX of Part...STANDARDS FOR HAZARDOUS AIR POLLUTANTS FOR SOURCE CATEGORIES (CONTINUED) National Emissions...Emission Limits for Tire Production Affected Sources As stated in § 63.5996, you...

2013-07-01

125

In-line rotating capacitive torque sensor  

DOEpatents

A method and apparatus for measuring torques developed along a rotating mechanical assembly comprising a rotating inner portion and a stationary outer portion. The rotating portion has an electrically-conductive flexing section fitted between two coaxial shafts in a configuration which varies radially in accordance with applied torque. The stationary portion comprises a plurality of conductive plates forming a surface concentric with and having a diameter slightly larger than the diameter of the rotating portion. The capacitance between the outer, nonrotating and inner, rotating portion varies with changes in the radial configuration of the rotating portion. Signal output varies approximately linearly with torque for small torques, nonlinearly for larger torques. The sensor is preferably surrounded by a conductive shell to minimize electrical interference from external sources.

Kronberg, James W. (P.O. Box 385, Beach Island, SC 29841)

1991-01-01

126

Estimating Torque Imparted on Spacecraft Using Telemetry  

NASA Technical Reports Server (NTRS)

There have been a number of missions with spacecraft flying by planetary moons with atmospheres; there will be future missions with similar flybys. When a spacecraft such as Cassini flies by a moon with an atmosphere, the spacecraft will experience an atmospheric torque. This torque could be used to determine the density of the atmosphere. This is because the relation between the atmospheric torque vector and the atmosphere density could be established analytically using the mass properties of the spacecraft, known drag coefficient of objects in free-molecular flow, and the spacecraft velocity relative to the moon. The density estimated in this way could be used to check results measured by science instruments. Since the proposed methodology could estimate disturbance torque as small as 0.02 N-m, it could also be used to estimate disturbance torque imparted on the spacecraft during high-altitude flybys.

Lee, Allan Y.; Wang, Eric K.; Macala, Glenn A.

2013-01-01

127

Environmental Qualification of an Actuator Torque Switch  

SciTech Connect

Environmental qualification testing was performed on a modified Limitorque torque switch for the torque switch safety functions in the Limitorque type SMB actuators located inside and outside containment in a nuclear power plant. The torque switch specimen was installed in a Limitorque SMB-1 electric actuator mounted on an 8'' Velan gate valve and operated with a customized programmable logic controller to allow normal torque switch behaviour to be observed. The present paper describes the qualification testing performed. The modified torque switch was aged to a 30-year service life at the normal service conditions for both inside and outside containment. Aging included radiation, thermal and cycle aging. A seismic test and then a combined Loss of Coolant Accident (LOCA) and Main Steam Line Break (MSLB) steam accident simulation were followed. After each stage of aging, functional tests were done to confirm normal insulation resistance, normal contact resistance and normal operation. (authors)

Chan, A.M.; Barreca, S.L. [Kinectrics, Inc., 800 Kipling Avenue Toronto, Ontario M8Z 6C4 (Canada); Kostela, T. [Ontario Power Generation, Inc., 700 University Avenue Toronto, Ontario, M5G 1X6 (Canada)

2006-07-01

128

In-line rotating capacitive torque sensor  

SciTech Connect

A method and apparatus for measuring torques developed along a rotating mechanical assembly comprising a rotating inner portion and a stationary outer portion. The rotating portion has an electrically-conductive flexing section fitted between two coaxial shafts in a configuration which varies radially in accordance with applied torque. The stationary portion comprises a plurality of conductive plates forming a surface concentric with and having a diameter slightly larger than the diameter of the rotating portion. The capacitance between the outer, nonrotating and inner, rotting portion varies with changes in the radial configuration of the rotating portion. Signal output varies approximately linearly with torque for small torques, nonlinearly for larger torques. The sensor is preferably surrounded by a conductive shell to minimize electrical interference from external sources. 8 figs.

Kronberg, J.W.

1990-01-08

129

Torque control during lingual anterior retraction without posterior appliances  

PubMed Central

Objective To evaluate the factors that affect torque control during anterior retraction when utilizing the C-retractor with a palatal miniplate as an exclusive source of anchorage without posterior appliances. Methods The C-retractor was modeled using a 3-dimensional beam element (0.9-mm-diameter stainless-steel wire) attached to mesh bonding pads. Various vertical heights and 2 attachment positions for the lingual anterior retraction hooks (LARHs) were evaluated. A force of 200 g was applied from each side hook of the miniplate to the splinted segment of 6 or 8 anterior teeth. Results During anterior retraction, an increase in the LARH vertical height increased the amount of lingual root torque and intrusion of the incisors. In particular, with increasing vertical height, the tooth displacement pattern changed from controlled tipping to bodily displacement and then to lingual root displacement. The effects were enhanced when the LARH was located between the central and lateral incisors, as compared to when the LARH was located between the lateral incisors and canines. Conclusions Three-dimensional lingual anterior retraction of the 6 or 8 anterior teeth can be accomplished using the palatal miniplate as the only anchorage source. Using LARHs at different heights or positions affects the quality of torque and intrusion.

Mo, Sung-Seo; Sung, Sang-Jin; Chung, Kyu-Rhim; Chun, Yun-Sic; Kook, Yoon-Ah; Nelson, Gerald

2013-01-01

130

Climate change induced rainfall patterns affect wheat productivity and agroecosystem functioning dependent on soil types  

NASA Astrophysics Data System (ADS)

Wheat is a crop of global importance supplying more than half of the world's population with carbohydrates. We examined, whether climate change induced rainfall patterns towards less frequent but heavier events alter wheat agroecosystem productivity and functioning under three different soil types. Therefore, in a full-factorial experiment Triticum aestivum L. was cultivated in 3 m2 lysimeter plots containing the soil types sandy calcaric phaeozem, gleyic phaeozem or calcic chernozem. Prognosticated rainfall patterns based on regionalised climate change model calculations were compared with current long-term rainfall patterns; each treatment combination was replicated three times. Future rainfall patterns significantly reduced wheat growth and yield, reduced the leaf area index, accelerated crop development, reduced arbuscular mycorrhizal fungi colonisation of roots, increased weed density and the stable carbon isotope signature (?13C) of both old and young wheat leaves. Different soil types affected wheat growth and yield, ecosystem root production as well as weed abundance and biomass. The interaction between climate and soil type was significant only for the harvest index. Our results suggest that even slight changes in rainfall patterns can significantly affect the functioning of wheat agroecosystems. These rainfall effects seemed to be little influenced by soil types suggesting more general impacts of climate change across different soil types. Wheat production under future conditions will likely become more challenging as further concurrent climate change factors become prevalent.

Tabi Tataw, James; Baier, Fabian; Krottenthaler, Florian; Pachler, Bernadette; Schwaiger, Elisabeth; Whylidal, Stefan; Formayer, Herbert; Hösch, Johannes; Baumgarten, Andreas; Zaller, Johann G.

2014-05-01

131

Encoding of tangential torque in responses of tactile afferent fibres innervating the fingerpad of the monkey  

PubMed Central

Torsional loads are ubiquitous during everyday dextrous manipulations. We examined how information about torque is provided to the sensorimotor control system by populations of tactile afferents. Torsional loads of different magnitudes were applied in clockwise and anticlockwise directions to a standard central site on the fingertip. Three different background levels of contact (grip) force were used. The median nerve was exposed in anaesthetized monkeys and single unit responses recorded from 66 slowly adapting type-I (SA-I) and 31 fast adapting type-I (FA-I) afferents innervating the distal segments of the fingertips. Most afferents were excited by torque but some were suppressed. Responses of the majority of both afferent types were scaled by torque magnitude applied in one or other direction, with the majority of FA-I afferent responses and about half of SA-I afferent responses scaled in both directions. Torque direction affected responses in both afferent types, but more so for the SA-I afferents. Latencies of the first spike in FA-I afferent responses depended on the parameters of the torque. We used a Parzen window classifier to assess the capacity of the SA-I and FA-I afferent populations to discriminate, concurrently and in real-time, the three stimulus parameters, namely background normal force, torque magnitude and direction. Despite the potentially confounding interactions between stimulus parameters, both the SA-I and the FA-I populations could extract torque magnitude accurately. The FA-I afferents signalled torque magnitude earlier than did the SA-I afferents, but torque direction was extracted more rapidly and more accurately by the SA-I afferent population.

Birznieks, Ingvars; Wheat, Heather E; Redmond, Stephen J; Salo, Lauren M; Lovell, Nigel H; Goodwin, Antony W

2010-01-01

132

Nuclear DNA content affects the productivity of conifer forests by altering hydraulic architecture  

NASA Astrophysics Data System (ADS)

Predictions of future global climate rely on feedbacks between terrestrial vegetation and the global carbon cycle, but the exact mechanisms underlying this relationship are still being discussed. One of the key knowledge gaps lies on the scaling of cellular processes to the ecosystem level. Here we examine whether an under-explored plant trait, inter-specific variation in the bulk amount of DNA in unreplicated somatic cells (2C DNA content), can explain inter-specific variation in the maximum productivity of conifer forests. We expected 2C DNA content to be negatively related to conifer productivity because: 1) it is positively correlated with cell volume (which, in turn, potentially affects structural features such as leaf mass area, a strong predictor of photosynthetic capacity); 2) it is positively correlated with stomatal size (with larger stomata leading to lower overall stomatal conductance and, by extension, lower CO2 uptake); and 3) larger genome sizes may reduce P availability in RNA (which has been hypothesized to slow growth). We present the results of regression and independent contrasts in different monospecific forests encompassing a 52º latitudinal gradient, each being dominated by 1 of 35 different conifer species. Contrary to expectations, we observed a positive correlation between genome size and maximum Gross Primary Productivity (R2 = 0.47) and also between genome size maximum tree height (R2 = 0.27). This correlation was apparently driven by the effects of genome size on stem hydraulics, since 2C DNA was positively correlated with wood density (R2 = 0.40) and also with resistance to cavitation (P50, R2 = 0.28). That is, increased genome sizes have a positive effect on the productivity of conifer forests by affecting the vascular tissues to increase their capacity for water transport. Our results shed a new light on the evolution of the vascular system of conifer forests and how they affect ecosystem productivity, and indicate the potential to further explore the trait of genome size for understanding global patterns of forest productivity.

Alday, Josu; Resco de Dios, Víctor

2014-05-01

133

Do non-native plant species affect the shape of productivity-diversity relationships?  

USGS Publications Warehouse

The relationship between ecosystem processes and species richness is an active area of research and speculation. Both theoretical and experimental studies have been conducted in numerous ecosystems. One finding of these studies is that the shape of the relationship between productivity and species richness varies considerably among ecosystems and at different spatial scales, though little is known about the relative importance of physical and biological mechanisms causing this variation. Moreover, despite widespread concern about changes in species' global distributions, it remains unclear if and how such large-scale changes may affect this relationship. We present a new conceptual model of how invasive species might modulate relationships between primary production and species richness. We tested this model using long-term data on relationships between aboveground net primary production and species richness in six North American terrestrial ecosystems. We show that primary production and abundance of non-native species are both significant predictors of species richness, though we fail to detect effects of invasion extent on the shapes of the relationship between species richness and primary production.

Drake, J. M.; Cleland, E. E.; Horner-Devine, M. C.; Fleishman, E.; Bowles, C.; Smith, M. D.; Carney, K.; Emery, S.; Gramling, J.; Vandermast, D. B.; Grace, J. B.

2008-01-01

134

Understanding mechanisms and factors related to implant fixation; a model study of removal torque.  

PubMed

Osseointegration is a prerequisite for achieving a stable long-term fixation and load-bearing capacity of bone anchored implants. Removal torque measurements are often used experimentally to evaluate the fixation of osseointegrated screw-shaped implants. However, a detailed understanding of the way different factors influence the result of removal torque measurements is lacking. The present study aims to identify the main factors contributing to anchorage. Individual factors important for implant fixation were identified using a model system with an experimental design in which cylindrical or screw-shaped samples were embedded in thermosetting polymers, in order to eliminate biological variation. Within the limits of the present study, it is concluded that surface topography and the mechanical properties of the medium surrounding the implant affect the maximum removal torque. In addition to displaying effects individually, these factors demonstrate interplay between them. The rotational speed was found not to influence the removal torque measurements within the investigated range. PMID:24566379

Stenlund, Patrik; Murase, Kohei; Stålhandske, Christina; Lausmaa, Jukka; Palmquist, Anders

2014-06-01

135

International Space Station Attitude Control and Energy Storage Experiment: Effects of Flywheel Torque  

NASA Technical Reports Server (NTRS)

The Attitude Control and Energy Storage Experiment is currently under development for the International Space Station; two counter-rotating flywheels will be levitated with magnetic bearings and placed in vacuum housings. The primary objective of the experiment is to store and discharge energy, in combination with existing batteries, into the electrical power system. The secondary objective is to use the flywheels to exert torque on the Station; a simple torque profile has been designed so that the Station's Control Moment Gyroscopes will be assisted in maintaining torque equilibrium attitude. Two energy storage contingencies could result in the inadvertent application of torque by the flywheels to the Station: an emergency shutdown of one flywheel rotor while the other remains spinning, and energy storage with only one rotor instead of the counterrotating pair. Analysis of these two contingencies shows that attitude control and the microgravity environment will not be adversely affected.

Roithmayr, Carlos M.

1999-01-01

136

The effect of rotating platform TKA on strain distribution and torque transmission on the proximal tibia.  

PubMed

Limited experimental data exist comparing the mechanical response of the tibial cortex between fixed and rotating platform (RP) total knee arthroplasty (TKA), particularly in the revision setting. We asked if RP-TKA significantly affects tibiofemoral torque and cortical stain response in both the primary and revision settings. Fixed and RP tibial trays were implanted into analogue tibias and biomechanically tested under axial and torsional loading. Torque and strain response were analyzed using digital image correlation. Fixed bearing designs exhibited 13.8 times greater torque (P<0.01), and 69% (P<0.01) higher cortical strain than RP designs. Strain response was similar in the primary and revision cohorts. The decrease in torque transfer could act as a safeguard to reduce stress, micromotion and torsional fatigue in scenario of poor bone stock. PMID:24290741

Malinzak, Robert A; Small, Scott R; Rogge, Renee D; Archer, Derek B; Oja, Jordan W; Berend, Michael E; Ritter, Merrill A

2014-03-01

137

Torque Ripple Reduction of Reluctance Torque Assisted Motors Using Asymmetric Flux Barriers  

NASA Astrophysics Data System (ADS)

Interior permanent magnet synchronous motor (IPMSM) is efficient and can be operated in wide speed region; therefore it is used widely. However, torque ripple of reluctance torque assisted motors, for example IPMSM and synchronous reluctance motor (SynRM), is very large. The skew is known in the prior art as a torque ripple reduction method of AC motors. Although the skew is effective for torque ripple reduction, structure is complicated and it has the disadvantage that average torque will decrease. The discontinuous variation of magnetic resistance between flux barriers and teeth cause the torque ripple. In this paper, in order to ease the discontinuous variation of magnetic resistance, flux barriers are asymmetrically designed so that the relative position relation between flux barriers and teeth may not be in agreement as much as possible. As a result, the torque ripple can be reduced dramatically without the average torque decrease. The experimental motor has been fabricated and the results of measuring torque ripple prove the validity of the torque ripple reduction using asymmetric flux barriers.

Hiramoto, Kenji; Takeda, Yoji; Sanada, Masayuki; Morimoto, Shigeo

138

Electrostatics in the environment: How they may affect health and productivity  

NASA Astrophysics Data System (ADS)

Lifestyles and the built environment have changed considerably during the past century and have greatly influenced the electric field, small air ion and charged submicron aerosol regimes to which individuals are often exposed. In particular the use of electrical items, synthetic materials/finishes and low humidity levels that can lead to the generation of high electrostatic charges, along with inadequate grounding protocols and building techniques which create 'Faraday cage'-like conditions, have all greatly altered the electromagnetic nature of the microclimates many people occupy for prolonged periods of time. It is suggested that the type, polarity and strengths of electric fields individuals are exposed to may affect their likelihood of succumbing to ill-health through influencing biological functioning, oxygen-uptake and retention rates of inhaled submicron contaminants to a far greater degree than previously realised. These factors can also influence the degree of local surface contamination and adhesion that occurs. It is further suggested that both health and work productivity can be affected by such factors, and that improved 'best practice' electro-hygiene/productivity protocols should be adopted wherever practical.

Jamieson, K. S.; Simon, H. M. Ap; Bell, J. N. B.

2008-12-01

139

Setting tool with retractable torque fingers  

SciTech Connect

A method is described of setting a liner in a well bore using a setting tool of the type adapted to be made up in a pipe string for releasably engaging a setting sleeve in a well bore, comprising the steps of: connecting a mandrel in the pipe string which has a setting nut with external connecting threads for engaging mating connecting threads located on the interior of a setting sleeve disposed about the mandrel, the mandrel being slidably disposed within the setting nut when the setting nut is engaging the setting sleeve, the mandrel being slidable between an extended, running-in position and a weight set-down position; mounting a torque collar on the mandrel exterior, the torque collar having at least one torque finger mounted thereon which is axially slidable on an external surface of the torque collar in a plane which is parallel to the longitudinal axis of the tool, the setting sleeve having at least one end notch adapted to receive the axially slidable torque finger; initially latching the mandrel to the setting sleeve with each torque finger received within its respective end notch; setting weight down on the pipe string from the well surface to release the latch and allow relative movement between the connecting threads of the setting nut and setting sleeve; applying right hand torque to the pipe string to release the connecting threads of the setting nut from the setting sleeve; temporarily lifting the pipe string and setting tool to test the disengagement of the setting nut; again resting the setting tool on the setting sleeve; rotating the pipe string to realign the torque finger and the setting sleeve end notch and reengage the torque finger with the end notch; and continuing to rotate to the right to rotate the setting sleeve during subsequent well bore operations.

Nevels, D.L.; Baugh, J.L.

1986-07-08

140

Canceling Torque Caused By Boiloff Of Cryogen  

NASA Technical Reports Server (NTRS)

Proposed technique for cancellation of small torques caused by venting of cryogens from tanks in spacecraft adaptable to use in making small corrections in orientations of terrestrial scientific instruments. Torque eliminated by directing exhaust gas through "T" vent. To cancel remaining small torque, that side of "T" from which exhaust produces smaller thrust heated just enough to equalize opposing thrusts. Concept useful in situations in which conventional electromagnetic actuators not suitable because of constraints related to temperature, radiation, or vibration and equipment required to be robust, simple, reliable, light in weight, and without moving parts.

Bhandari, Pradeep

1993-01-01

141

Magnetic torque on a rotating superconducting sphere  

NASA Technical Reports Server (NTRS)

The London theory of superconductivity is used to calculate the torque on a superconducting sphere rotating in a uniform applied magnetic field. The London theory is combined with classical electrodynamics for a calculation of the direct effect of excess charge on a rotating superconducting sphere. Classical electrodynamics, with the assumption of a perfect Meissner effect, is used to calculate the torque on a superconducting sphere rotating in an arbitrary magnetic induction; this macroscopic approach yields results which are correct to first order. Using the same approach, the torque due to a current loop encircling the rotating sphere is calculated.

Holdeman, L. B.

1975-01-01

142

Tidal Torques are the Answer  

NASA Astrophysics Data System (ADS)

Angular momentum conservation places severe restrictions on the possible steady-state differential rotation of any body. The only terms that survive the time-averaging of the zonal momentum equation (which expresses this conservation rule) are due to tidal torques, Lorentz (magnetic) forces, and friction. These terms are all much smaller than the canceling terms due to Coriolis forces and Reynolds stresses. So numerical models which do not solve the equations of motion exactly will inevitably give erroneous results. On the other hand, the time-average equations are straightforward to solve analytically. The results are that the balance between tidal torques and friction determines the differential rotation; and the tidal dissipation and friction together determine the diabatic heating which maintains the required baroclinicity (horizontal temperature gradients). In conducting regions, the dynamo equation and the time-average zonal momentum equation form a nonlinear, but dissipative, system which is mathematically equivalent to the famous Lorenz system. The behavior of the resulting ?? dynamo can be quite various, but depends on only a few parameters (the strength of the ?-effect [?], the strength of the differential rotation [?], and the magnetic Prandtl number [?/?] being the most important). It is totally independent of the Coriolis force, which does not appear in the time-average zonal balance. Equilibrium is reached when there is a balance between the Lorentz force and friction with B2R2 ~ ???(D - Dmin), where the dynamo number D ~ ??R2/?2. The time and spatial dependence of the dynamo is a function of D as indicated in the Table. In particular, there is a critical value of D above which the steady-state solutions of the dynamo are unstable, resulting in possible chaotic behavior. The jets and thermal structure of the neutral atmosphere principally depend on the tidal forcing frequency, the (vertical) thermal structure of the troposphere, the viscosity, and the Prandtl number. These parameters can be determined by straightforward assimilation of the observed winds and temperatures into a nearly linear model based on the strengths of tidal modes. This simple approach explains all of the observed differential rotations and hydromagnetic dynamos in the solar system.t;

Houben, H.

2012-12-01

143

Torque ripple and misalignment torque compensation for the built-in torque sensor of harmonic drive systems  

Microsoft Academic Search

A harmonic drive is a compact, lightweight, and high-ratio torque transmission device which is used in many electrically actuated robot manipulators. In this paper a built-in torque sensor for harmonic-drive systems is examined in detail. The method proposed by Hashimoto, in which strain gauges are directly mounted on the flexspline, is employed and improved in this paper. To minimize sensing

H. D. Taghirad; P. R. Belanger

1998-01-01

144

Radiative torques: analytical model and basic properties  

NASA Astrophysics Data System (ADS)

We attempt to get a physical insight into grain alignment processes by studying basic properties of radiative torques (RATs). For this purpose we consider a simple toy model of a helical grain that reproduces well the basic features of RATs. The model grain consists of a spheroidal body with a mirror attached at an angle to it. Being very simple, the model allows analytical description of RATs that act upon it. We show a good correspondence of RATs obtained for this model and those of irregular grains calculated by DDSCAT. Our analysis of the role of different torque components for grain alignment reveals that one of the three RAT components does not affect the alignment, but induces only for grain precession. The other two components provide a generic alignment with grain long axes perpendicular to the radiation direction, if the radiation dominates the grain precession, and perpendicular to magnetic field, otherwise. The latter coincides with the famous predictions of the Davis-Greenstein process, but our model does not invoke paramagnetic relaxation. In fact, we identify a narrow range of angles between the radiation beam and the magnetic field, for which the alignment is opposite to the Davis-Greenstein predictions. This range is likely to vanish, however, in the presence of thermal wobbling of grains. In addition, we find that a substantial part of grains subjected to RATs gets aligned with low angular momentum, which testifies that most of the grains in diffuse interstellar medium do not rotate fast, that is, rotate with thermal or even subthermal velocities. This tendency of RATs to decrease grain angular velocity as a result of the RAT alignment decreases the degree of polarization, by decreasing the degree of internal alignment, that is, the alignment of angular momentum with the grain axes. For the radiation-dominated environments, we find that the alignment can take place on the time-scale much shorter than the time of gaseous damping of grain rotation. This effect makes grains a more reliable tracer of magnetic fields. In addition, we study a self-similar scaling of RATs as a function of ?/aeff. We show that the self-similarity is useful for studying grain alignment by a broad spectrum of radiation, that is, interstellar radiation field.

Lazarian, A.; Hoang, Thiem

2007-07-01

145

The effect of extraneous movements on peak torque and constant joint angle torque-velocity curves.  

PubMed

During isokinetic knee testing, some subjects flex the trunk and contralateral knee during knee extension and the trunk and contralateral knee during knee flexion. This investigation assessed the effect of these extraneous movements on peak and constant joint angle torque (15 degrees below horizontal). Twenty-one subjects performed isokinetic knee extensions and flexions at 60, 180, and 300 degrees/sec under stabilized and nonstabilized conditions. The nonstabilized testing was performed with intentional trunk and contralateral leg movements. The stabilized condition resulted in greater torque values than the nonstabilized condition for extension and flexion for both peak torque and constant joint angle torque. The angle at which flexion peak torque occurred was further from full extension at 60 and 180 degrees/sec under the nonstabilized condition, while no differences were found for extension. These results indicate that extraneous movements can decrease torque output, which may be due to changes in muscle length caused by the extraneous movements. PMID:8728528

Weir, J P; Evans, S A; Housh, M L

1996-05-01

146

Turbulent Torques on Protoplanets in a Dead Zone  

NASA Astrophysics Data System (ADS)

Migration of protoplanets in their gaseous host disks may be largely responsible for the observed orbital distribution of extrasolar planets. Recent simulations have shown that the magnetorotational turbulence thought to drive accretion in protoplanetary disks can affect migration by turning it into an orbital random walk. However, these simulations neglected the disk's ionization structure. Low ionization fraction near the midplane of the disk can decouple the magnetic field from the gas, forming a dead zone with reduced or no turbulence. Here, to understand the effect of dead zones on protoplanetary migration, we perform numerical simulations of a small region of a stratified disk with magnetorotational turbulence confined to thin active layers above and below the midplane. Turbulence in the active layers exerts decreased, but still measurable, gravitational torques on a protoplanet located at the disk midplane. We find a decrease of 2 orders of magnitude in the diffusion coefficient for dead zones with dead-to-active surface density ratios approaching realistic values in protoplanetary disks. This torque arises primarily from density fluctuations within a distance of one scale height of the protoplanet. Turbulent torques have correlation times of only ~0.3 orbital periods and apparently time-stationary distributions. These properties are encouraging signs that stochastic methods can be used to determine the orbital evolution of populations of protoplanets under turbulent migration. Our results indicate that dead zones may be dynamically distinct regions for protoplanetary migration.

Oishi, Jeffrey S.; Mac Low, Mordecai-Mark; Menou, Kristen

2007-11-01

147

Turbulent Torques on Protoplanets in a Dead Zone  

NASA Astrophysics Data System (ADS)

Dynamical migration of protoplanets seems likely to explain the observed distribution of extrasolar planets. Previous work on laminar disks predicts short migration times (less than the disk lifetime). This is a significant problem for the "core accretion" scenario, in which giant planets are thought to form from small, rocky protoplanetary cores in the disk. However, there have been recent suggestions that the turbulence providing accretion in protoplanetary disks might enhance migration by turning laminar migration into a random walk, possibly providing a solution to the short migration timescale. I will report the results of local, 3D simulations of MHD turbulence with quiescent "dead zones" of varying sizes at the midplane. I demonstrate that turbulent torques on a massless protoplanet at the midplane are strongly affected by the presence of dead zones, which considerably decrease the total turbulent torque on the planet. In all cases, the torques have a finite correlation time and are dominated by gas close to the planet. These results can be incorporated into statistical models for the survival of a population of protoplanets in a disk, allowing a better understanding of the nature of planet migration and survival.

Oishi, Jeffrey S.; Mac Low, M.; Menou, K.

2006-12-01

148

Greenhouse tomato limited cluster production systems: crop management practices affect yield.  

PubMed

Limited-cluster production systems may be a useful strategy to increase crop production and profitability for the greenhouse tomato (Lycopersicon esculentum Mill). In this study, using an ebb-and-flood hydroponics system, we modified plant architecture and spacing and determined the effects on fruit yield and harvest index at two light levels. Single-cluster plants pruned to allow two leaves above the cluster had 25% higher fruit yields than did plants pruned directly above the cluster; this was due to an increase in fruit weight, not fruit number. Both fruit yield and harvest index were greater for all single-cluster plants at the higher light level because of increases in both fruit weight and fruit number. Fruit yield for two-cluster plants was 30% to 40% higher than for single-cluster plants, and there was little difference in the dates or length of the harvest period. Fruit yield for three-cluster plants was not significantly different from that of two-cluster plants; moreover, the harvest period was delayed by 5 days. Plant density (5.5, 7.4, 9.2 plants/m2) affected fruit yield/plant, but not fruit yield/unit area. Given the higher costs for materials and labor associated with higher plant densities, a two-cluster crop at 5.5 plants/m2 with two leaves above the cluster was the best of the production system strategies tested. PMID:11858257

Logendra, L S; Gianfagna, T J; Specca, D R; Janes, H W

2001-08-01

149

Nitrogen and phosphorus fertilization negatively affects strigolactone production and exudation in sorghum.  

PubMed

Strigolactones (SLs) are essential host recognition signals for both root parasitic plants and arbuscular mycorrhizal fungi, and SLs or their metabolites function as a novel class of plant hormones regulating shoot and root architecture. Our previous study indicated that nitrogen (N) deficiency as well as phosphorus (P) deficiency in sorghum enhanced root content and exudation of 5-deoxystrigol, one of the major SLs produced by sorghum. In the present study, we examined how N and P fertilization affects SL production and exudation in sorghum plants subjected to short- (5 days) or long-term (10 days) N or P deficiency and demonstrated their common and distinct features. The root contents and exudation of SLs in the N- or P-deficient sorghum plants grown for 6, 12 or 24 h with or without N or P fertilization were quantified by LC-MS/MS. In general, without fertilization, root contents and exudation of SLs stayed at similar levels at 6 and 12 h and then significantly increased at 24 h. The production of SLs responded more quickly to P fertilization than the secretion of SLs, while regulation of SL secretion began earlier after N fertilization. It is suggested that sorghum plants regulate SL production and exudation when they are subjected to nutrient deficiencies depending on the type of nutrient and degree of deficiency. PMID:23925853

Yoneyama, Kaori; Xie, Xiaonan; Kisugi, Takaya; Nomura, Takahito; Yoneyama, Koichi

2013-11-01

150

EDITORIAL: Spin-transfer-torque-induced phenomena Spin-transfer-torque-induced phenomena  

Microsoft Academic Search

This cluster, consisting of five invited articles on spin-transfer torque, offers the very first review covering both magnetization reversal and domain-wall displacement induced by a spin-polarized current. Since the first theoretical proposal on spin-transfer torque---reported by Berger and Slonczewski independently---spin-transfer torque has been experimentally demonstrated in both vertical magnetoresistive nano-pillars and lateral ferromagnetic nano-wires. In the former structures, an electrical

Atsufumi Hirohata

2011-01-01

151

Noise in Spin Torque Oscillators  

NASA Astrophysics Data System (ADS)

In a spin torque oscillator (STO), a direct current passing through a reference magnetic layer becomes spin polarized and transfers angular momentum to a second magnetic layer that is excited into steady-state oscillation. The oscillating magnetization causes an oscillating device resistance, through either the giant magnetoresistance effect or the tunneling magnetoresistance effect, which in combination with the bias current generates an oscillating voltage as the output signal. Interest in potential applications of STOs in integrated microwave circuits is driven by their rapid frequency tunability, small size (<100 nm), and compatibility with standard semiconductor processing techniques. For any oscillator, noise is both an important figure of merit for applications and a useful probe of internal physical processes. I will summarize the theoretical and experimental state of our understanding of frequency and phase noise in a variety of oscillators, considering both time domain and frequency domain measurements. Some aspects can be explained by the effects of thermal fluctuations. Others, such as frequency noise that varies as 1/f at low frequencies, are not yet understood.

Keller, Mark

2011-03-01

152

Brake assembly including torque monitor  

SciTech Connect

This patent describes a brake assembly for selectively braking rotation of an input shaft extending from a control rod drive having a longitudinal centerline axis, the shaft being rotatable for selectively inserting and withdrawing a control rod in a nuclear reactor vessel. It comprises a stationary base; an annular bearing mounted to the base; a brake mounted to the bearing; a backing plate mounted to the bearing; a first braking pad fixedly joined to the backing plate; a rotor disc fixedly connected to the input shaft and disposed adjacent to the first pad; a second braking pad disposed adjacent to the rotor disc; and means for selectively clamping the first and second pads against the rotor disc for braking the input shaft; means for torsionally restraining the brake including: a pin extending outwardly from the backing plate toward the base; and a spring extending from the base to the pin and generally perpendicular to the centerline axis; and means for monitoring the angle for monitoring braking torque capability of the brake.

Dillmann, C.W.

1992-07-21

153

A Computational Model of Torque Generation: Neural, Contractile, Metabolic and Musculoskeletal Components  

PubMed Central

The pathway of voluntary joint torque production includes motor neuron recruitment and rate-coding, sarcolemmal depolarization and calcium release by the sarcoplasmic reticulum, force generation by motor proteins within skeletal muscle, and force transmission by tendon across the joint. The direct source of energetic support for this process is ATP hydrolysis. It is possible to examine portions of this physiologic pathway using various in vivo and in vitro techniques, but an integrated view of the multiple processes that ultimately impact joint torque remains elusive. To address this gap, we present a comprehensive computational model of the combined neuromuscular and musculoskeletal systems that includes novel components related to intracellular bioenergetics function. Components representing excitatory drive, muscle activation, force generation, metabolic perturbations, and torque production during voluntary human ankle dorsiflexion were constructed, using a combination of experimentally-derived data and literature values. Simulation results were validated by comparison with torque and metabolic data obtained in vivo. The model successfully predicted peak and submaximal voluntary and electrically-elicited torque output, and accurately simulated the metabolic perturbations associated with voluntary contractions. This novel, comprehensive model could be used to better understand impact of global effectors such as age and disease on various components of the neuromuscular system, and ultimately, voluntary torque output.

Callahan, Damien M.; Umberger, Brian R.; Kent-Braun, Jane A.

2013-01-01

154

14 CFR 25.361 - Engine torque.  

Code of Federal Regulations, 2010 CFR

...accounting for propeller control system malfunction, including quick feathering, acting simultaneously with 1g level flight loads...due to malfunction or structural failure (such as compressor jamming). (2) A limit engine torque load imposed by the...

2009-01-01

155

14 CFR 25.361 - Engine torque.  

Code of Federal Regulations, 2010 CFR

...accounting for propeller control system malfunction, including quick feathering, acting simultaneously with 1g level flight loads...due to malfunction or structural failure (such as compressor jamming). (2) A limit engine torque load imposed by the...

2010-01-01

156

Advanced Inductive Plasmas with Low Torque Startup  

NASA Astrophysics Data System (ADS)

Experiments on DIII-D have been performed to investigate the access and performance of advanced inductive discharges produced with zero net torque for the full duration of the plasma. With low torque, the plasma is particularly susceptible to 2/1 neoclassical tearing modes, which typically slow and lock, spoiling confinement and ending the high beta phase. Attempts to reduce the residual error field did not appear to significantly modify the stability at low torque. The addition of a modest amount of electron cyclotron heating (1 MW), configured for current drive aimed at the q=2 surface, appeared adequate to reduce the mode amplitude sufficiently to allow stable operation at ?N˜2.5 with q95˜4.3. Details of the stability, confinement and current profile, and comparison with typical high torque advanced inductive discharges will be presented.

Solomon, W. M.; Okabayashi, M.; Buttery, R. J.; Ferron, J. R.; Garofalo, A. M.; Jackson, G. L.; La Haye, R. J.; Luce, T. C.; Petty, C. C.; Politzer, P. A.; Welander, A. S.; Hanson, J. M.; in, Y.; Lanctot, M. J.; Turco, F.

2011-11-01

157

14 CFR 23.361 - Engine torque.  

Code of Federal Regulations, 2013 CFR

...the limit loads from flight condition A of § 23...this section, a limit engine torque corresponding...accounting for propeller control system malfunction...simultaneously with lg level flight loads. In the absence... (b) For turbine engine installations,...

2014-01-01

158

Cutting Fluid Performance Testing: Tapping Torque Test.  

National Technical Information Service (NTIS)

A tapping torque test was conducted on 10 cutting and tapping fluid samples. The test was performed to establish the comparative efficacy of competitive fluids in controlled conditions. The recent health concern over trichloroethane in tapping fluids has ...

E. E. Kelley

1989-01-01

159

Dynamics of a Split Torque Helicopter Transmission.  

National Technical Information Service (NTIS)

Split torque designs, proposed as alternatives to traditional planetary designs for helicopter main rotor transmissions, can save weight and be more reliable than traditional designs. This report presents the results of an analytical study of the system d...

T. L. Krantz

1994-01-01

160

40 CFR 1065.310 - Torque calibration.  

Code of Federal Regulations, 2010 CFR

...dynamometer during calibration to reduce frictional static hysteresis. Determine each weight's force by multiplying its NIST-traceable...dynamometer during calibration to reduce frictional static hysteresis. In this case, the reference torque is determined...

2010-07-01

161

Compliant humanoid robot control by the torque transformer  

Microsoft Academic Search

This paper presents a new control architecture for compliant motion control and safe physical interaction between humanoid robot and human. One of the key technologies in this framework is the torque transformer, which enables the implementation of joint torque control on the traditional joint position controlled robots. In this framework, the torque control is accomplished by converting desired joint torque

Taizo Yoshikawa; Oussama Khatib

2009-01-01

162

Yielding Torque-Tube System Reduces Crash Injuries  

NASA Technical Reports Server (NTRS)

Yielding torque-tube system minimizes injuries by limiting load transferred to occupant in crash. When properly integrated into seat structure, torque tube yields in plastic deformation stage of material and maintains a relatively constant resistance to applied torque for many degrees of rotation. Yielding torque-tube system is expected to find application in aircraft and automobile industries.

Mcsmith, D. G.

1982-01-01

163

How the Structure of Mesoscale Precipitation Systems Affects their Production of Transient Luminous Events  

NASA Astrophysics Data System (ADS)

Recently, Lang et al. (2010) analyzed the parent lightning of transient luminous events (TLEs) in the context of the structure and evolution of two mesoscale convective systems (MCSs). These two MCSs were very different - one a giant symmetric leading-line/trailing stratiform storm, and one a small asymmetric MCS that contained a mesoscale convective vortex. These structural differences were associated with substantially different TLE-parent lightning structure as well as TLE production. The results suggested that TLE (especially sprite) production, and TLE-parent positive charge altitude, depend on MCS morphology. Current work is focused on analyzing the structure, evolution, lightning behavior, and TLE production of additional MCSs over various regions of the United States. Several additional TLE-producing MCS cases already have been identified for the years 2008-2010, featuring a variety of organizational modes (symmetric, asymmetric, and other more exotic varieties) in different meteorological regimes (including some cold-season cases). More cases will be incorporated as they occur and are observed. Data sources include geostationary satellite imagery, Doppler radar, three-dimensional lightning mapping networks, ground-strike detection networks, charge moment change measurements, and low-light video observations. The ultimate goal is to further test the hypothesis that MCS structure affects TLE production, and if so to quantify its impact. Research on two Oklahoma case studies, a multicellular system that occurred on 24 March 2009 and a classic bow-echo MCS that occurred on 19 August 2009, is ongoing. Over a 2.5-h period, the March case produced 23 observed TLEs (all sprites) whose parent flashes occurred within 175 km of the Oklahoma Lightning Mapping Array (OKLMA). The median altitude of LMA sources during the TLEs was 5.9 km above Mean Sea Level (MSL), or -19.2 °C. The August storm produced, in 2.5 hours, 34 TLEs (all sprites) with 32 of those having parent flashes within 175 km of the OKLMA. The median altitude for those flashes was higher, 7.1 km MSL, though at a warmer temperature of -14.7 °C due to the time of season. Based on analysis of the radar structures and the lightning data, the two storms support the hypothesized effects of organizational mode on sprite production. In particular, sprite production by the August MCS appeared to benefit from its leading-line/trailing-stratiform structure, which likely led to a higher altitude for the dominant stratiform positive charge layer. This would increase charge moment change, a key metric for the production of sprites.

Lang, T. J.; Lyons, W.; Rutledge, S. A.; Cummer, S. A.; MacGorman, D. R.

2011-12-01

164

Electric arc furnace impact on generator torque  

Microsoft Academic Search

Electric arc furnaces draw power in pulses at approximately 5-6 Hz. This pulsing load is generally modeled as step-load-step-unload where the step is a complete load and complete unload. This step in power creates a step in the electrical torque of a generator supplying electricity to the electric arc furnace. This step in torque creates a torsional interaction that can

Mark W. Baldwin

2004-01-01

165

40 CFR Table 10 to Subpart Xxxx of... - Continuous Compliance With the Emission Limits for Tire Production Affected Sources  

Code of Federal Regulations, 2013 CFR

As stated in § 63.6004, you must show continuous compliance with the emission limits for tire production affected sources according to the following table: For . . . For the following emission limit . . . You must demonstrate continuous compliance by . . ....

2013-07-01

166

40 CFR 63.5987 - What are my alternatives for meeting the emission limits for tire cord production affected sources?  

Code of Federal Regulations, 2013 CFR

...FOR HAZARDOUS AIR POLLUTANTS FOR SOURCE CATEGORIES (CONTINUED) National Emissions Standards for Hazardous Air Pollutants: Rubber Tire Manufacturing Emission Limits for Tire Cord Production Affected Sources § 63.5987 What are my alternatives...

2013-07-01

167

40 CFR Table 12 to Subpart Xxxx of... - Continuous Compliance With the Emission Limits for Tire Cord Production Affected Sources  

Code of Federal Regulations, 2010 CFR

...Production Affected Sources 12 Table 12 to Subpart XXXX of Part 63 Protection of Environment ENVIRONMENTAL...Rubber Tire Manufacturing Pt. 63, Subpt. XXXX, Table 12 Table 12 to Subpart XXXX of Part 63âContinuous Compliance With the...

2010-07-01

168

Preparing for rectal microbicides: sociocultural factors affecting product uptake among potential South american users.  

PubMed

Objectives. We examined views on rectal microbicides (RMs), a potential HIV prevention option, among men who have sex with men and transgender women in 3 South American cities. Methods. During September 2009 to September 2010, we conducted 10 focus groups and 36 in-depth interviews (n?=?140) in Lima and Iquitos, Peru, and Guayaquil, Ecuador, to examine 5 RM domains: knowledge, thoughts and opinions about RM as an HIV prevention tool, use, condoms, and social concerns. We coded emergent themes in recorded and transcribed data sets and extracted representative quotes. We collected sociodemographic information with a self-administered questionnaire. Results. RM issues identified included limited knowledge; concerns regarding plausibility, side effects, and efficacy; impact on condom use; target users (insertive vs receptive partners); and access concerns. Conclusions. Understanding the sociocultural issues affecting RMs is critical to their uptake and should be addressed prior to product launch. PMID:24825222

Galea, Jerome T; Kinsler, Janni J; Imrie, John; Nureña, César R; Ruiz, Lucía; Galarza, Luis Fernando; Sánchez, Jorge; Cunningham, William E

2014-06-01

169

The Receptor for Advanced Glycation End Products (RAGE) Affects T Cell Differentiation in OVA Induced Asthma  

PubMed Central

The receptor for glycation end products (RAGE) has been previously implicated in shaping the adaptive immune response. RAGE is expressed in T cells after activation and constitutively in T cells from patients with diabetes. The effects of RAGE on adaptive immune responses are not clear: Previous reports show that RAGE blockade affects Th1 responses. To clarify the role of RAGE in adaptive immune responses and the mechanisms of its effects, we examined whether RAGE plays a role in T cell activation in a Th2 response involving ovalbumin (OVA)-induced asthma in mice. WT and RAGE deficient wild-type and OT-II mice, expressing a T cell receptor specific for OVA, were immunized intranasally with OVA. Lung cellular infiltration and T cell responses were analyzed by immunostaining, FACS, and multiplex bead analyses for cytokines. RAGE deficient mice showed reduced cellular infiltration in the bronchial alveolar lavage fluid and impaired T cell activation in the mediastinal lymph nodes when compared with WT mice. In addition, RAGE deficiency resulted in reduced OT-II T cell infiltration of the lung and impaired IFN? and IL-5 production when compared with WT mice and reduced infiltration when transferred into WT hosts. When cultured under conditions favoring the differentiation of T cells subsets, RAGE deficient T cells showed reduced production of IFN? but increased production of IL-17. Our data show a stimulatory role for RAGE in T activation in OVA-induced asthma. This role is largely mediated by the effects of RAGE on T cell proliferation and differentiation. These findings suggest that RAGE may play a regulatory role in T cell responses following immune activation.

Akirav, Eitan M.; Henegariu, Octavian; Preston-Hurlburt, Paula; Schmidt, Ann Marie; Clynes, Raphael; Herold, Kevan C.

2014-01-01

170

Decreased summer drought affects plant productivity and soil carbon dynamics in Mediterranean woodland  

NASA Astrophysics Data System (ADS)

Precipitation patterns are expected to change in the Mediterranean region within the next decades, with projected decreases in total rainfall and increases in extreme events. We manipulated precipitation patterns in a Mediterranean woodland, dominated by Arbutus unedo L., to study the effects of changing precipitation regimes on above-ground net primary production (ANPP) and soil C dynamics, specifically plant-derived C input to soil and soil respiration (SR). Experimental plots were exposed to either a 20 % reduction of throughfall or to water addition targeted at maintaining soil water content above a minimum of 10 % v/v. Treatments were compared to control plots which received ambient precipitation. The throughfall manipulation experiment started in 2004 and we report data up to the 2009 growing season. Enhanced soil moisture during summer months highly stimulated annual stem primary production, litter fall, SR and net annual plant-derived C input to soil which on average increased by 130 %, 26 %, 50 % and 220 %, respectively, as compared to control. In contrast, the 20 % reduction in throughfall (equivalent to 10 % reduction of precipitation) did not significantly change soil moisture at the site, and therefore did not significantly affect ANPP or SR. We conclude that minor changes (around 10 % reduction) in precipitation amount are not likely to significantly affect ANPP or soil C dynamics in Mediterranean woodland. However, if summer rain increases, C cycling will significantly accelerate but soil C stocks are not likely to be changed in the short-term. More studies involving modelling of long term C dynamics are needed to predict if the estimated increases in soil C input under wet conditions is going to be sustained and if labile C is being substituted to stable C, with a negative effect on long term soil C stocks.

Cotrufo, M. F.; Alberti, G.; Inglima, I.; Marjanovi?, H.; Lecain, D.; Zaldei, A.; Peressotti, A.; Miglietta, F.

2011-06-01

171

Decreased summer drought affects plant productivity and soil carbon dynamics in a Mediterranean woodland  

NASA Astrophysics Data System (ADS)

Precipitation patterns are expected to change in the Mediterranean region within the next decades, with projected decreases in total rainfall and increases in extreme events. We manipulated precipitation patterns in a Mediterranean woodland, dominated by Arbutus unedo L., to study the effects of changing precipitation regimes on above-ground net primary production (ANPP) and soil C dynamics, specifically plant-derived C input to soil and soil respiration (SR). Experimental plots were exposed to either a 20 % reduction of throughfall or to water addition targeted at maintaining soil water content above a minimum of 10 % v/v. Treatments were compared to control plots which received ambient precipitation. Enhanced soil moisture during summer months highly stimulated annual stem primary production, litter fall, SR and net annual plant-derived C input to soil which on average increased by 130 %, 26 %, 58 % and 220 %, respectively, as compared to the control. In contrast, the 20 % reduction in throughfall (equivalent to 10 % reduction in precipitation) did not significantly change soil moisture at the site, and therefore did not significantly affect ANPP or SR. We conclude that minor changes (around 10 % reduction) in precipitation amount are not likely to significantly affect ANPP or soil C dynamics in Mediterranean woodlands. However, if summer rain increases, C cycling will significantly accelerate but soil C stocks are not likely to be changed in the short-term. More studies involving modelling of long-term C dynamics are needed to predict if the estimated increases in soil C input under wet conditions is going to be sustained and if labile C is being substituted to stable C, with a negative effect on long-term soil C stocks.

Cotrufo, M. F.; Alberti, G.; Inglima, I.; Marjanovi?, H.; Lecain, D.; Zaldei, A.; Peressotti, A.; Miglietta, F.

2011-09-01

172

Extraneous torque and compensation control on the electric load simulator  

NASA Astrophysics Data System (ADS)

In this paper a novel motor-drive load simulator based on compensation control strategy is proposed and designed. Through analyzing the torque control system consisting of DC torque motor, PWM module and torque sensor, it is shown that performance of the motor-drive load simulator is possible to be as good as that of the electro-hydraulic load simulator in the range of small torque. In the course of loading, the rotation of the actuator would cause a strong disturbance torque through the motor back-EMF, which produces extraneous torque similar as in electro-hydraulic load simulator. This paper analyzes the cause of extraneous torque inside the torque motor in detail and presents an appropriate compensation control with which the extraneous torque can be compensated and the good performance of the torque control system can be obtained. The results of simulation indicate that the compensation is very effective and the track performance is according with the request.

Jiao, Zongxia; Li, Chenggong; Ren, Zhiting

2003-09-01

173

Analysis of Cogging Torque and its Effect on Direct Torque Control (DTC) in a Segmented Interior Permanent Magnet Machine  

Microsoft Academic Search

This paper investigates reduced cogging torque seen in the Segmented Interior Permanent Magnet (SIPM) machine and explores the effects of cogging torque on direct torque control (DTC) performance. In the segmented IPM machine, the pole magnets are segmented to provide an improved flux-weakening capability to the rotor. The cogging torque of the segmented IPM machine is found to be significantly

Rukmi Dutta; Saad Sayeef; M. F. Rahman

2007-01-01

174

Robust speed control of IM with torque feedforward control  

Microsoft Academic Search

The authors describe a digital signal processor-based (DSP-based) robust speed control for an induction motor (IM) with the load-torque observer and the torque feedforward control. In the proposed system, the load torque is estimated by the minimal-order state observer based on the torque component of a vector-controlled IM. Using the load-torque observer, a speed controller can be provided with a

Makoto Iwasaki; N. Matusi

1993-01-01

175

Potentiation Increases Peak Twitch Torque by Enhancing Rates of Torque Development and Relaxation  

PubMed Central

The aim of this study was to measure the extent to which potentiation changes in response to an isometric maximal voluntary contraction. Eleven physically active subjects participated in two separate studies. Single stimulus of electrical stimulation of the femoral nerve was used to measure torque at rest in unpotentiated quadriceps muscles (study 1 and 2), and potentiated quadriceps muscles torque in a 10 min period after a 5 s isometric maximal voluntary contraction of the quadriceps muscles (study 1). Additionally, potentiated quadriceps muscles torque was measured every min after a further 10 maximal voluntary contractions repeated every min (study 2). Electrical stimulation repeated several times without previous maximal voluntary contraction showed similar peak twitch torque. Peak twitch torque 4 s after a 5 s maximal voluntary contraction increased by 45±13% (study 1) and by 56±10% (study 2), the rate of torque development by 53±13% and 82±29%, and the rate of relaxation by 50±17% and 59±22%, respectively, but potentiation was lost already two min after a 5 s maximal voluntary contraction. There was a tendency for peak twitch torque to increase for the first five repeated maximal voluntary contractions, suggesting increased potentiation with additional maximal voluntary contractions. Correlations for peak twitch torque vs the rate of torque development and for the rate of relaxation were r2= 0.94 and r2=0.97. The correlation between peak twitch torque, the rate of torque development and the rate of relaxation suggests that potentiation is due to instantaneous changes in skeletal muscle contractility and relaxation.

Froyd, Christian; Beltrami, Fernando Gabe; Jensen, J?rgen; Noakes, Timothy David

2013-01-01

176

Direct torque control of induction machines with constant switching frequency and reduced torque ripple  

Microsoft Academic Search

Direct torque control (DTC) of induction machines is known to have a simple control structure with comparable performance to that of the field-oriented control technique. Two major problems that are usually associated with DTC drives are: switching frequency that varies with operating conditions and high torque ripple. To solve these problems, and at the same time retain the simple control

Nik Rumzi Nik Idris; Abdul Halim Mohamed Yatim

2004-01-01

177

Isometric force production parameters during normal and experimental low back pain conditions  

PubMed Central

Background The control of force and its between-trial variability are often taken as critical determinants of motor performance. Subjects performed isometric trunk flexion and extension forces without and with experiment pain to examine if pain yields changes in the control of trunk forces. The objective of this study is to determine if experimental low back pain modifies trunk isometric force production. Methods Ten control subjects participated in this study. They were required to exert 50 and 75% of their isometric maximal trunk flexion and extension torque. In a learning phase preceding the non painful and painful trials, visual and verbal feedbacks were provided. Then, subjects were asked to perform 10 trials without any feedback. Time to peak torque, time to peak torque variability, peak torque variability as well as constant and absolute error in peak torque were calculated. Time to peak and peak dF/dt were computed to determine if the first peak of dF/dt could predict the peak torque achieved. Results Absolute and constant errors were higher in the presence of a painful electrical stimulation. Furthermore, peak torque variability for the higher level of force was increased with in the presence of experimental pain. The linear regressions between peak dF/dt, time to peak dF/dt and peak torque were similar for both conditions. Experimental low back pain yielded increased absolute and constant errors as well as a greater peak torque variability for the higher levels of force. The control strategy, however, remained the same between the non painful and painful condition. Cutaneous pain affects some isometric force production parameters but modifications of motor control strategies are not implemented spontaneously. Conclusions It is hypothesized that adaptation of motor strategies to low back pain is implemented gradually over time. This would enable LBP patients to perform their daily tasks with presumably less pain and more accuracy.

Descarreaux, Martin; Blouin, Jean-Sebastien; Teasdale, Normand

2005-01-01

178

Equilibria of a charged artificial satellite subject to gravitational and Lorentz torques  

NASA Astrophysics Data System (ADS)

The attitude dynamics of a rigid artificial satellite subject to a gravity gradient and Lorentz torques in a circular orbit are considered. Lorentz torque is developed on the basis of the electrodynamic effects of the Lorentz force acting on the charged satellite's surface. We assume that the satellite is moving in a Low Earth Orbit in the geomagnetic field, which is considered to be a dipole. Our model of torque due to the Lorentz force is developed for an artificial satellite with a general shape, and the nonlinear differential equations of Euler are used to describe its attitude orientation. All equilibrium positions are determined and conditions for their existence are obtained. The numerical results show that the charge q and radius ?0 of the center of charge for the satellite provide a certain type of semi-passive control for the attitude of the satellite. The technique for this kind of control would be to increase or decrease the electrostatic screening on the satellite. The results obtained confirm that the change in charge can affect the magnitude of the Lorentz torque, which can also affect control of the satellite. Moreover, the relationship between magnitude of the Lorentz torque and inclination of the orbit is investigated.

Abdel-Aziz, Yehia A.; Shoaib, Muhammad

2014-07-01

179

Force, Torque and Stiffness: Interactions in Perceptual Discrimination  

PubMed Central

Three experiments investigated whether force and torque cues interact in haptic discrimination of force, torque and stiffness, and if so, how. The statistical relation between force and torque was manipulated across four experimental conditions: Either one type of cue varied while the other was constant, or both varied so as to be positively correlated, negatively correlated, or uncorrelated. Experiment 1 showed that the subjects’ ability to discriminate force was improved by positively correlated torque but impaired with uncorrelated torque, as compared to the constant torque condition. Corresponding effects were found in Experiment 2 for the influence of force on torque discrimination. These findings indicate that force and torque are integrated in perception, rather than being processed as separate dimensions. A further experiment demonstrated facilitation of stiffness discrimination by correlated force and torque, whether the correlation was positive or negative. The findings suggest new means of augmenting haptic feedback to facilitate perception of the properties of soft objects.

Wu, Bing; Klatzky, Roberta L.; Hollis, Ralph L.

2011-01-01

180

Torque shudder protection device and method  

DOEpatents

A torque shudder protection device for an induction machine includes a flux command generator for supplying a steady state flux command and a torque shudder detector for supplying a status including a negative status to indicate a lack of torque shudder and a positive status to indicate a presence of torque shudder. A flux adapter uses the steady state flux command and the status to supply a present flux command identical to the steady state flux command for a negative status and different from the steady state flux command for a positive status. A limiter can receive the present flux command, prevent the present flux command from exceeding a predetermined maximum flux command magnitude, and supply the present flux command to a field oriented controller. After determining a critical electrical excitation frequency at which a torque shudder occurs for the induction machine, a flux adjuster can monitor the electrical excitation frequency of the induction machine and adjust a flux command to prevent the monitored electrical excitation frequency from reaching the critical electrical excitation frequency.

King, Robert D. (Schenectady, NY); De Doncker, Rik W. A. A. (Malvern, PA); Szczesny, Paul M. (Ballston Lake, NY)

1997-01-01

181

Feasibility study for convertible engine torque converter  

NASA Technical Reports Server (NTRS)

The feasibility study has shown that a dump/fill type torque converter has excellent potential for the convertible fan/shaft engine. The torque converter space requirement permits internal housing within the normal flow path of a turbofan engine at acceptable engine weight. The unit permits operating the engine in the turboshaft mode by decoupling the fan. To convert to turbofan mode, the torque converter overdrive capability bring the fan speed up to the power turbine speed to permit engagement of a mechanical lockup device when the shaft speed are synchronized. The conversion to turbofan mode can be made without drop of power turbine speed in less than 10 sec. Total thrust delivered to the aircraft by the proprotor, fan, and engine during tansient can be controlled to prevent loss of air speed or altitude. Heat rejection to the oil is low, and additional oil cooling capacity is not required. The turbofan engine aerodynamic design is basically uncompromised by convertibility and allows proper fan design for quiet and efficient cruise operation. Although the results of the feasibility study are exceedingly encouraging, it must be noted that they are based on extrapolation of limited existing data on torque converters. A component test program with three trial torque converter designs and concurrent computer modeling for fluid flow, stress, and dynamics, updated with test results from each unit, is recommended.

1985-01-01

182

Potential of trypanotolerance as a contribution to sustainable livestock production in tsetse affected Africa.  

PubMed

Tsetse transmitted trypanosomiasis is possibly the major constraint on livestock and agriculture development in Subsaharan Africa. Control of the disease has been based on vector control as well as on the use of trypanocidal drugs to treat or prevent infection in animals. Both control methods are effective but have proven not to be sustainable. Moreover, the development of a vaccine against trypanosomiasis is unlikely to be successful in the near future. On the other hand, trypanotolerant cattle, like the N'Dama can survive and produce in tsetse affected areas without interventions. This taurine breed has been indigenous to Africa for approximately 7,000 years and forms presently about 6% of the bovine population of Africa. Generally the N'Dama are kept in the rural areas by the small-scale farmer as a multi-purpose animal. Recent studies have defined management characteristics and assessed the production potential at the village level and under ranching conditions of N'Dama cattle exposed to various levels of tsetse challenge. Furthermore, experimental infections showed conclusively the superior resistance to the effects of infection of the N'Dama cattle when compared to zebu cattle and have confirmed that trypanotolerance is innate in N'Dama cattle. Studies have been conducted on development of protective humoral and cellular responses, the regulation of parasite multiplication and control of anaemia. These studies provided tools for identifying components of trypanotolerance. The ability to resist the development of anaemia in the face of infection, has shown to be correlated with the capacity to be productive; moreover, PCV values can serve as selection criterium for trypanotolerance. Subsequently, repeatabilities and heritabilities of trypanotolerance and performance traits were estimated.(ABSTRACT TRUNCATED AT 250 WORDS) PMID:8285944

Paling, R W; Dwinger, R H

1993-06-01

183

Physical processes affecting availability of dissolved silicate for diatom production in the Arabian Sea  

NASA Technical Reports Server (NTRS)

A passive tracer to represent dissolved silicate concentrations, with biologically realistic uptake kinetics, is successfully incorporated into a three-dimensional, eddy-resolving, ocean circulation model of the Indian Ocean. Hypotheses are tested to evaluate physical processes which potentially affect the availability of silicate for diatom production in the Arabian Sea. An alternative mechanism is offered to the idea that open ocean upwelling is primarily responsible for the high, vertical nutrient flux and consequent large-scale phytoplankton bloom in the northwestern Arabian Sea during the southwest monsoon. Model results show that dissolved silicate in surface waters available for uptake by diatoms is primarily influenced by the intensity of nearshore upwelling from soutwest monsoonal wind forcing and by the offshore advective transport of surface waters. The upwelling, which in the model occurs within 200 +/- 50 km of the coast, appears to be a result of a combination of coastal upwelling, Elkman pumping, and divergence of the coastal flow as it turns offshore. Localized intensifications of silicate concentrations appear to be hydrodynamically driven and geographically correlated to coastal topographic features. The absence of diatoms in sediments of the eastern Arabian Basin is consistent with modeled distributional patterns of dissolved silicate resulting from limited westward advection of upwelled coastal waters from the western continental margin of India and rapid uptake of available silicate by diatoms. Concentrations of modeled silicate become sufficiently low to become unavailable for diatom production in the eastern Arabian Sea, a region between 61 deg E and 70 deg E at 8 deg N on the south, with the east and west boundaries converging on the north at approximately 67 deg E, 20 deg N.

Young, David K.; Kindle, John C.

1994-01-01

184

Denitrifying Bacterial Communities Affect Current Production and Nitrous Oxide Accumulation in a Microbial Fuel Cell  

PubMed Central

The biocathodic reduction of nitrate in Microbial Fuel Cells (MFCs) is an alternative to remove nitrogen in low carbon to nitrogen wastewater and relies entirely on microbial activity. In this paper the community composition of denitrifiers in the cathode of a MFC is analysed in relation to added electron acceptors (nitrate and nitrite) and organic matter in the cathode. Nitrate reducers and nitrite reducers were highly affected by the operational conditions and displayed high diversity. The number of retrieved species-level Operational Taxonomic Units (OTUs) for narG, napA, nirS and nirK genes was 11, 10, 31 and 22, respectively. In contrast, nitrous oxide reducers remained virtually unchanged at all conditions. About 90% of the retrieved nosZ sequences grouped in a single OTU with a high similarity with Oligotropha carboxidovorans nosZ gene. nirS-containing denitrifiers were dominant at all conditions and accounted for a significant amount of the total bacterial density. Current production decreased from 15.0 A·m?3 NCC (Net Cathodic Compartment), when nitrate was used as an electron acceptor, to 14.1 A·m?3 NCC in the case of nitrite. Contrarily, nitrous oxide (N2O) accumulation in the MFC was higher when nitrite was used as the main electron acceptor and accounted for 70% of gaseous nitrogen. Relative abundance of nitrite to nitrous oxide reducers, calculated as (qnirS+qnirK)/qnosZ, correlated positively with N2O emissions. Collectively, data indicate that bacteria catalysing the initial denitrification steps in a MFC are highly influenced by main electron acceptors and have a major influence on current production and N2O accumulation.

Vilar-Sanz, Ariadna; Puig, Sebastia; Garcia-Lledo, Arantzazu; Trias, Rosalia; Balaguer, M. Dolors; Colprim, Jesus; Baneras, Lluis

2013-01-01

185

Plant Products Affect Growth and Digestive Efficiency of Cultured Florida Pompano (Trachinotus carolinus) Fed Compounded Diets  

PubMed Central

Costs of compounded diets containing fish meal as a primary protein source can be expected to rise as fish meal prices increase in response to static supply and growing demand. Alternatives to fish meal are needed to reduce production costs in many aquaculture enterprises. Some plant proteins are potential replacements for fish meal because of their amino acid composition, lower cost and wide availability. In this study, we measured utilization of soybean meal (SBM) and soy protein concentrate (SPC) by Florida pompano fed compounded diets, to determine the efficacy of these products as fish meal replacements. We also calculated apparent digestibility coefficients (ADCs) for canola meal (CM), corn gluten meal (CGM), and distillers dried grains with solubles (DDGS), following typical methods for digestibility trials. Juvenile Florida pompano were fed fish-meal-free diets containing graded levels of SBM and SPC, and weight gain was compared to a control diet that contained SBM, SPC, and fish meal. Fish fed diets that contained 25–30 percent SBM in combination with 43–39 percent SPC had weight gain equivalent to fish fed the control diet with fish meal, while weight gain of fish fed other soy combinations was significantly less than that of the control group. Apparent crude protein digestibility of CGM was significantly higher than that of DDGS but not significantly different from CM. Apparent energy digestibility of DDGS was significantly lower than CGM but significantly higher than CM. Findings suggested that composition of the reference diet used in a digestibility trial affects the values of calculated ADCs, in addition to the chemical and physical attributes of the test ingredient.

Lech, Gregory P.; Reigh, Robert C.

2012-01-01

186

Predicting the Affects of Climate Change on Evapotranspiration and Agricultural Productivity of Semi-arid Basins  

NASA Astrophysics Data System (ADS)

Many arid and semi-arid regions around the world are experiencing water shortages that have become increasingly problematic. Since the late 1800s, upstream diversions in Nevada's Walker River have delivered irrigation supply to the surrounding agricultural fields resulting in a dramatic water level decline of the terminal Walker Lake. Salinity has also increased because the only outflow from the lake is evaporation from the lake surface. The Heihe River basin of northwestern China, a similar semi-arid catchment, is also facing losses from evaporation of terminal locations, agricultural diversions and evapotranspiration (ET) of crops. Irrigated agriculture is now experiencing increased competition for use of diminishing water resources while a demand for ecological conservation continues to grow. It is important to understand how the existing agriculture in these regions will respond as climate changes. Predicting the affects of climate change on groundwater flow, surface water flow, ET and agricultural productivity of the Walker and Heihe River basins is essential for future conservation of water resources. ET estimates from remote sensing techniques can provide estimates of crop water consumption. By determining similarities of both hydrologic cycles, critical components missing in both systems can be determined and predictions of impacts of climate change and human management strategies can be assessed.

Peri, L.; Tyler, S. W.; Zheng, C.; Pohll, G. M.; Yao, Y.

2013-12-01

187

Beneficial mycorrhizal symbionts affecting the production of health-promoting phytochemicals.  

PubMed

Fresh fruits and vegetables are largely investigated for their content in vitamins, mineral nutrients, dietary fibers, and plant secondary metabolites, collectively called phytochemicals, which play a beneficial role in human health. Quantity and quality of phytochemicals may be detected by using different analytical techniques, providing accurate quantification and identification of single molecules, along with their molecular structures, and allowing metabolome analyses of plant-based foods. Phytochemicals concentration and profiles are affected by biotic and abiotic factors linked to plant genotype, crop management, harvest season, soil quality, available nutrients, light, and water. Soil health and biological fertility play a key role in the production of safe plant foods, as a result of the action of beneficial soil microorganisms, in particular of the root symbionts arbuscular mycorrhizal fungi. They improve plant nutrition and health and induce changes in secondary metabolism leading to enhanced biosynthesis of health-promoting phytochemicals, such as polyphenols, carotenoids, flavonoids, phytoestrogens, and to a higher activity of antioxidant enzymes. In this review we discuss reports on health-promoting phytochemicals and analytical methods used for their identification and quantification in plants, and on arbuscular mycorrhizal fungi impact on fruits and vegetables nutritional and nutraceutical value. PMID:25025092

Sbrana, Cristiana; Avio, Luciano; Giovannetti, Manuela

2014-06-01

188

Self-induced torque in hyperbolic metamaterials.  

PubMed

Optical forces constitute a fundamental phenomenon important in various fields of science, from astronomy to biology. Generally, intense external radiation sources are required to achieve measurable effects suitable for applications. Here we demonstrate that quantum emitters placed in a homogeneous anisotropic medium induce self-torques, aligning themselves in the well-defined direction determined by an anisotropy, in order to maximize their radiation efficiency. We develop a universal quantum-mechanical theory of self-induced torques acting on an emitter placed in a material environment. The theoretical framework is based on the radiation reaction approach utilizing the rigorous Langevin local quantization of electromagnetic excitations. We show more than 2 orders of magnitude enhancement of the self-torque by an anisotropic metamaterial with hyperbolic dispersion, having negative ratio of permittivity tensor components, in comparison with conventional anisotropic crystals with the highest naturally available anisotropy. PMID:23909352

Ginzburg, Pavel; Krasavin, Alexey V; Poddubny, Alexander N; Belov, Pavel A; Kivshar, Yuri S; Zayats, Anatoly V

2013-07-19

189

Helicopter Anti-Torque System Using Strakes  

NASA Technical Reports Server (NTRS)

A helicopter is disclosed with a system for controlling main-rotor torque which reduces the power and size requirements of conventional anti-torque means. The torque countering forces are generated by disrupting the main rotor downwash flowing around the fuselage. The downwash flow is separated from the fuselage surface by a strake positioned at a specified location on the fuselage. This location is determined by the particular helicopter wash pattern and fuselage configuration, generally being located between 20 deg before top dead center (TDC) and 80 deg from TDC on the fuselage side to which the main rotor blade approaches during rotation. The strake extends along the fuselage from the cabin section to the aft end and can be continuous or separated for aerodynamic surfaces such as a horizontal stabilizer.

Kelley, H. L.; Wilson, J. C.; Phelps, A. E. (inventors)

1984-01-01

190

Atmospheric Gravitational Torque Variations Based on Various Gravity Fields  

NASA Technical Reports Server (NTRS)

Advancements in the study of the Earth's variable rate of rotation and the motion of its rotation axis have given impetus to the analysis of the torques between the atmosphere, oceans and solid Earth. The output from global general circulation models of the atmosphere (pressure, surface stress) is being used as input to the torque computations. Gravitational torque between the atmosphere, oceans and solid Earth is an important component of the torque budget. Computation of the gravitational torque involves the adoption of a gravitational model from a wide variety available. The purpose of this investigation is to ascertain to what extent this choice might influence the results of gravitational torque computations.

Sanchez, Braulio V.; Rowlands, David; Smith, David E. (Technical Monitor)

2001-01-01

191

Reduced elbow extension torque during vibrations.  

PubMed

Impact sports and vibration platforms trigger vibrations within soft tissues and the skeleton. Although the long-term effects of vibrations on the body have been studied extensively, the acute effects of vibrations are little understood. This study determined the influence of acute vibrations at different frequencies and elbow angles on maximal isometric elbow extension torque and muscle activity. Vibrations were generated by a pneumatic vibrator attached to the lever of a dynamometer, and were applied on the forearm of 15 healthy female subjects. The subjects were instructed to push maximally against the lever at three different elbow angles, while extension torque and muscle activity were quantified and compared between vibration and non-vibration (control) conditions. A change in vibration frequency had no significant effects on torque and muscle activity although vibrations in general decreased the maximal extension torque relative to the control by 1.8% (±5.7%, p>0.05), 7.4% (±7.9%, p<0.01), and 5.0% (±8.2%, p<0.01) at elbow angles of 60°, 90°, and 120°, respectively. Electromyographic activity increased significantly between ?30% and 40% in both triceps and biceps with vibrations. It is speculated that a similar increase in muscle activity between agonist and antagonist, in combination with an unequal increase in muscle moment arms about the elbow joint, limit the maximal extension torque during exposure to vibrations. This study showed that maximal extension torque decreased during vibration exposure while muscle activity increased and suggests that vibrations may be counterproductive during activities requiring maximal strength but potentially beneficial for strength training. PMID:22771229

Friesenbichler, Bernd; Coza, Aurel; Nigg, Benno M

2012-08-31

192

Torque limit of PM motors for field-weakening region operation  

DOEpatents

The invention includes a motor controller and technique for controlling a permanent magnet motor. In accordance with one aspect of the present technique, a permanent magnet motor is controlled by receiving a torque command, determining a physical torque limit based on a stator frequency, determining a theoretical torque limit based on a maximum available voltage and motor inductance ratio, and limiting the torque command to the smaller of the physical torque limit and the theoretical torque limit. Receiving the torque command may include normalizing the torque command to obtain a normalized torque command, determining the physical torque limit may include determining a normalized physical torque limit, determining a theoretical torque limit may include determining a normalized theoretical torque limit, and limiting the torque command may include limiting the normalized torque command to the smaller of the normalized physical torque limit and the normalized theoretical torque limit.

Royak, Semyon (Beachwood, OH); Harbaugh, Mark M. (Richfield, OH)

2012-02-14

193

Influence of two levels of caffeine on maximal torque at selected angular velocities.  

PubMed

The purpose of this study was to determine the effect of two doses of caffeine on peak torque and muscle endurance in the knee extensors and flexors. Twenty males and 16 females were randomly assigned to one of three groups: 600 mg caffeine, 300 mg caffeine, or a control receiving a placebo. Subjects with similar caffeine consumption history were used and all subjects abstained from caffeine usage for 24 hours prior to testing. Subjects were tested for maximal strength and endurance at 75, 180, and 300 degrees per second using a Cybex II Isokinetic Dynomometer interfaced with a Cybex Data Reduction Computer. After pretesting, each subject was given one of three solutions using a double-blind design. Following a one hour rest and absorption period, the subjects were again tested. Data were analyzed using a 3 x 2 repeated measures analysis of variance with a grouping factor at three levels (600 mg vs 300 mg vs 0 mg) and a trial factor at two levels (pre- vs posttest). The following variables were analyzed at all angular velocities: peak torque and subsequent joint angle, peak torque at 30 degrees, and peak torque at 70 degrees. At 300 degrees per second, the dependent variables were total torque for 15 repetitions, total torque for the first 3 repetitions, and total torque for the last 3 repetitions. The results indicated no significant changes from pre- to posttest. It was concluded that maximal strength and endurance was not affected by the two levels of caffeine used in this study and that caffeine may not be considered an ergogenic aid in strength output in subjects naive to resistance training. PMID:1753719

Jacobson, B H; Edwards, S W

1991-06-01

194

Evoked EMG-based torque prediction under muscle fatigue in implanted neural stimulation  

NASA Astrophysics Data System (ADS)

In patients with complete spinal cord injury, fatigue occurs rapidly and there is no proprioceptive feedback regarding the current muscle condition. Therefore, it is essential to monitor the muscle state and assess the expected muscle response to improve the current FES system toward adaptive force/torque control in the presence of muscle fatigue. Our team implanted neural and epimysial electrodes in a complete paraplegic patient in 1999. We carried out a case study, in the specific case of implanted stimulation, in order to verify the corresponding torque prediction based on stimulus evoked EMG (eEMG) when muscle fatigue is occurring during electrical stimulation. Indeed, in implanted stimulation, the relationship between stimulation parameters and output torques is more stable than external stimulation in which the electrode location strongly affects the quality of the recruitment. Thus, the assumption that changes in the stimulation-torque relationship would be mainly due to muscle fatigue can be made reasonably. The eEMG was proved to be correlated to the generated torque during the continuous stimulation while the frequency of eEMG also decreased during fatigue. The median frequency showed a similar variation trend to the mean absolute value of eEMG. Torque prediction during fatigue-inducing tests was performed based on eEMG in model cross-validation where the model was identified using recruitment test data. The torque prediction, apart from the potentiation period, showed acceptable tracking performances that would enable us to perform adaptive closed-loop control through implanted neural stimulation in the future.

Hayashibe, Mitsuhiro; Zhang, Qin; Guiraud, David; Fattal, Charles

2011-10-01

195

Recent Advances of Reluctance Torque Assisted Motors  

NASA Astrophysics Data System (ADS)

The history of motor technology began with the discovery of electromagnetic induction by Faraday. Various kinds of motors were developed by the recent progress of the fundamental technology (magnetic structure, magnetic material, drive circuit, control method). Especially, motors using the reluctance torque have many advantages and some of them are used as high efficient motors. This paper overviews recent advances of reluctance torque assisted motors such as Switched Reluctance Motor (SRM), Synchronous Reluctance Motor (SynRM) and Interior Permanent Magnet Synchronous Motor (IPMSM).

Ohyama, Kazunobu

196

Optimizing the rate and timing of phosphogypsum application to magnesium-affected soils for crop yield and water productivity enhancement  

Microsoft Academic Search

The levels of magnesium (Mg2+) in irrigation waters and soils are increasing in several irrigation schemes worldwide. Excess levels of Mg2+ in irrigation waters and\\/or in soils negatively affect soil physical properties (infiltration rate and hydraulic conductivity) and ultimately crop growth and yield. Although few studies have been undertaken on productivity enhancement of magnesium-affected soils by adding a source of

F. Vyshpolsky; K. Mukhamedjanov; U. Bekbaev; S. Ibatullin; T. Yuldashev; A. D. Noble; A. Mirzabaev; A. Aw-Hassan; M. Qadir

2010-01-01

197

Reducing the net torque and flow ripple effects of multiple hydraulic piston motor drives  

NASA Technical Reports Server (NTRS)

The torque and flow ripple effects which result when multiple hydraulic motors are used to drive a single motion of a mechanical device can significantly affect the way in which the device performs. This article presents a mathematical model describing the torque and flow ripple effects of a bent-axis hydraulic piston motor. The model is used to show how the ripple magnitude can be reduced when multiple motors are used to drive a motion. A discussion of the hydraulic servo system of the 70-m antennas located with the Deep Space Network is included to demonstrate the application of the concepts presented.

Bartos, R. D.

1992-01-01

198

Long-term affected energy production of waste to energy technologies identified by use of energy system analysis  

SciTech Connect

Affected energy production is often decisive for the outcome of consequential life-cycle assessments when comparing the potential environmental impact of products or services. Affected energy production is however difficult to determine. In this article the future long-term affected energy production is identified by use of energy system analysis. The focus is on different uses of waste for energy production. The Waste-to-Energy technologies analysed include co-combustion of coal and waste, anaerobic digestion and thermal gasification. The analysis is based on optimization of both investments and production of electricity, district heating and bio-fuel in a future possible energy system in 2025 in the countries of the Northern European electricity market (Denmark, Norway, Sweden, Finland and Germany). Scenarios with different CO{sub 2} quota costs are analysed. It is demonstrated that the waste incineration continues to treat the largest amount of waste. Investments in new waste incineration capacity may, however, be superseded by investments in new Waste-to-Energy technologies, particularly those utilising sorted fractions such as organic waste and refuse derived fuel. The changed use of waste proves to always affect a combination of technologies. What is affected varies among the different Waste-to-Energy technologies and is furthermore dependent on the CO{sub 2} quota costs and on the geographical scope. The necessity for investments in flexibility measures varies with the different technologies such as storage of heat and waste as well as expansion of district heating networks. Finally, inflexible technologies such as nuclear power plants are shown to be affected.

Muenster, M., E-mail: maem@risoe.dtu.d [Risoe National Laboratory for Sustainable Energy, Technical University of Denmark, Frederiksborgvej 399, 4000 Roskilde (Denmark); Meibom, P. [Risoe National Laboratory for Sustainable Energy, Technical University of Denmark, Frederiksborgvej 399, 4000 Roskilde (Denmark)

2010-12-15

199

Long-term affected energy production of waste to energy technologies identified by use of energy system analysis.  

PubMed

Affected energy production is often decisive for the outcome of consequential life-cycle assessments when comparing the potential environmental impact of products or services. Affected energy production is however difficult to determine. In this article the future long-term affected energy production is identified by use of energy system analysis. The focus is on different uses of waste for energy production. The Waste-to-Energy technologies analysed include co-combustion of coal and waste, anaerobic digestion and thermal gasification. The analysis is based on optimization of both investments and production of electricity, district heating and bio-fuel in a future possible energy system in 2025 in the countries of the Northern European electricity market (Denmark, Norway, Sweden, Finland and Germany). Scenarios with different CO(2) quota costs are analysed. It is demonstrated that the waste incineration continues to treat the largest amount of waste. Investments in new waste incineration capacity may, however, be superseded by investments in new Waste-to-Energy technologies, particularly those utilising sorted fractions such as organic waste and refuse derived fuel. The changed use of waste proves to always affect a combination of technologies. What is affected varies among the different Waste-to-Energy technologies and is furthermore dependent on the CO(2) quota costs and on the geographical scope. The necessity for investments in flexibility measures varies with the different technologies such as storage of heat and waste as well as expansion of district heating networks. Finally, inflexible technologies such as nuclear power plants are shown to be affected. PMID:20471819

Münster, M; Meibom, P

2010-12-01

200

GFP affects human T cell activation and cytokine production following in vitro stimulation.  

PubMed

There are many Green Fluorescent Proteins (GFPs) originating from diverse species that are invaluable to cell biologists today because of their ability to provide experimental visualization of protein expression. Since their initial discovery, they have been modified and improved to provide more stable variants with emission ranges spanning a wide array of colors. Due to their ease of expression both in-vitro and in-vivo, they are an attractive choice for use as markers in molecular biology. GFPs are generally assumed to have negligible effects on the cells to which they have been introduced. However, a growing number of reports indicate that this is not always the case. Consequently, because of GFP's ubiquitous use, it is important to document the nature and extent of unintended effects. In this report, we find that GFP affects T cell activation, leading to defects in clustering, upregulation of the activation marker CD25 and IL-2 cytokine production following stimulation in human primary T cells that also express TurboGFP. We utilized a reporter assay which has been routinely used to assay the NF-?B pathway and found reduced NF-?B activitation in stimulated HEK293 and HeLa cells that were co-transfected with TurboGFP, suggesting that GFP interferes with signaling through the NF-?B pathway. These findings indicate that the utilization of GFP-tagged vectors may negatively impact in vitro experiments in T cells, emphasizing the critical importance of controls to identify any GFP-induced effects. PMID:23577054

Koelsch, Kristi A; Wang, YuJing; Maier-Moore, Jacen S; Sawalha, Amr H; Wren, Jonathan D

2013-01-01

201

Auxins affected ginsenoside production and growth of hairy roots in Panax hybrid.  

PubMed

Hairy roots of interspecific hybrid ginseng (Panax ginseng x P. quinquefolium), induced by Agrobacterium rhizogenes ATCC 15834, grew well in B5 liquid media supplemented with 2.5 microM auxins (3-indole butyric acid (IBA), 1-naphtaleneacetic acid (NAA) and 3-indoleacetic acid (IAA)). The hairy roots cultured in B5 liquid medium supplemented with 2.5 microM IBA showed best growth (6.39 g fresh weight per a flask, at week 8). The highest content of the total ginsenosides was 1.63% as dry weight at week 8 when cultured with 2.5 microM NAA. The different auxins affected the numbers and lateral branching roots. Especially, 2.5 microM IBA promoted the lateral root formation (43.7+/-4.0 roots, at week 8), and 2.5 microM NAA promoted the lateral root growth (45.3+/-5.6 mm, at week 8). The growth and ginsenosides production of 8-week old hairy roots cultured in B5 liquid media supplemented with IBA and NAA combinations were also investigated. Hairy roots produced higher amounts of ginsenosides in B5 liquid media supplemented with 0.5-1.0 microM IBA and NAA combinations than that cultured in B5 liquid media supplemented with only IBA and NAA. The highest yield of ginsenoside was obtained when cultured with 0.5 microM IBA and 1.0 microM IBA combination (6.38 mg per a flask, at week 8). PMID:15133240

Washida, Daisuke; Shimomura, Koichiro; Takido, Michio; Kitanaka, Susumu

2004-05-01

202

Pulsed electromagnetic fields stimulation affects BMD and local factor production of rats with disuse osteoporosis.  

PubMed

Pulsed electromagnetic fields (PEMF) have been used widely to treat nonunion fractures and related problems in bone healing, as a biological and physical method. With the use of Helmholtz coils and PEMF stimulators to generate uniform time-varying electromagnetic fields, the effects of extremely low frequency electromagnetic fields on bone mineral density (BMD) and local factor production in disuse osteoporosis (DOP) rats were investigated. Eighty 4-month-old female Sprague Dawley (SD) rats were randomly divided into intact (INT) group, DOP group, calcitonin-treated (CT) group, and PEMF stimulation group. The right hindlimbs of all the rats were immobilized by tibia-tail fixation except for those rats in the INT group. Rats in the CT group were injected with calcitonin (2 IU/kg, i.p., once a day) and rats in the PEMF group were irradiated with PEMF immediately postoperative. The BMD, serum transforming growth factor-beta 1 (TGF-beta1), and interleukin-6 (IL-6) concentration of the proximal femur were measured 1, 2, 4, and 8 weeks after treatment. Compared with the CT and DOP groups, the BMD and serum TGF-beta1 concentration in the PEMF group increased significantly after 8 weeks. The IL-6 concentration in the DOP group was elevated significantly after operation. The PEMF group showed significantly lower IL-6 level than the DOP group. The results found demonstrate that PEMF stimulation can efficiently suppress bone mass loss. We, therefore, conclude that PEMF may affect bone remodeling process through promoting TGF-beta1 secretion and inhibiting IL-6 expression. PMID:19670410

Shen, Wei-Wei; Zhao, Jian-Hua

2010-02-01

203

ALOX5 gene variants affect eicosanoid production and response to fish oil supplementation[S  

PubMed Central

The objective of this study was to determine whether 5-lipoxygenase (ALOX5) gene variants associated with cardiovascular disease affect eicosanoid production by monocytes. The study was a randomized, double-masked, parallel intervention trial with fish oil (5.0 g of fish oil daily, containing 2.0 g of eicosapentaenoic acid [EPA] and 1.0 g of docosahexaenoic acid [DHA]) or placebo oil (5.0 g of corn/soy mixture). A total of 116 subjects (68% female, 20–59 years old) of African American ancestry enrolled, and 98 subjects completed the study. Neither ALOX5 protein nor arachidonic acid-derived LTB4, LTD4, and LTE4 varied by genotype, but 5-hydroxyeicosatetraenoate (5-HETE), 6-trans-LTB4, 5-oxo-ETE, 15-HETE, and 5,15-diHETE levels were higher in subjects homozygous for the ALOX5 promoter allele containing five Sp1 element tandem repeats (“55” genotype) than in subjects with one deletion (d) (three or four repeats) and one common (“d5” genotype) allele or with two deletion (“dd”) alleles. The EPA-derived metabolites 5-HEPE and 15-HEPE and the DHA-derived metabolite 17-HDoHE had similar associations with genotype and increased with supplementation; 5-HEPE and 15-HEPE increased, and 5-oxo-ETE decreased to a greater degree in the 55 than in the other genotypes. This differential eicosanoid response is consistent with the previously observed interaction of these variants with dietary intake of omega-3 fatty acids in predicting cardiovascular disease risk.

Stephensen, Charles B.; Armstrong, Patrice; Newman, John W.; Pedersen, Theresa L.; Legault, Jillian; Schuster, Gertrud U.; Kelley, Darshan; Vikman, Susanna; Hartiala, Jaana; Nassir, Rami; Seldin, Michael F.; Allayee, Hooman

2011-01-01

204

Dynamics of spin torque switching in all-perpendicular spin valve nanopillars  

NASA Astrophysics Data System (ADS)

We present a systematic experimental study of the spin-torque-induced magnetic switching statistics at room temperature, using all-perpendicularly magnetized spin-valves as a model system. Three physical regimes are distinguished: a short-time ballistic limit below a few nanoseconds, where spin-torque dominates the reversal dynamics from a thermal distribution of initial conditions; a long time limit, where the magnetization reversal probability is determined by spin-torque-amplified thermal activation; and a cross-over regime, where the spin-torque and thermal agitation both contribute. For a basic quantitative understanding of the physical processes involved, an analytical macrospin model is presented which contains both spin-torque dynamics and finite temperature effects. The latter was treated rigorously using a Fokker-Plank formalism, and solved numerically for specific sets of parameters relevant to the experiments to determine the switching probability behavior in the short-time and cross-over regimes. This analysis shows that thermal fluctuations during magnetization reversal greatly affect the switching probability over all the time scales studied, even in the short-time limit.

Liu, H.; Bedau, D.; Sun, J. Z.; Mangin, S.; Fullerton, E. E.; Katine, J. A.; Kent, A. D.

2014-05-01

205

Coupling between switching regulation and torque generation in bacterial flagellar motor  

PubMed Central

The bacterial flagellar motor plays a crucial role in both bacterial locomotion and chemotaxis. Recent experiments reveal that the switching dynamics of the motor depend on the rotation speed of the motor, and thus the motor torque, non-monotonically. Here we present a unified mathematical model which treats motor torque generation based on experimental torque-speed curves and the torque-dependent switching based on the conformational spread model. The model successfully reproduces the observed switching rate as a function of the rotation speed, and provides a generic physical explanation independent of most details. A stator affects the switching dynamics through two mechanisms: accelerating the conformational flipping rate of individual rotor-switching units, which contributes most when the stator works at a high torque and thus a low speed; and influencing a larger number of rotor-switching units within unit time, whose contribution is the greatest when the motor rotates at a high speed. Consequently, the switching rate shows a maximum at intermediate speed, where the above two mechanisms find an optimal output. The load-switching relation may serve as a mechanism for sensing the physical environment, similar to the chemotaxis mechanism for sensing the chemical environment. It may also coordinate the switch dynamics of motors within the same cell.

Bai, Fan; Minamino, Tohru; Wu, Zhanghan; Namba, Keiichi

2013-01-01

206

Robust torque optimization for BLDC spindle motors  

Microsoft Academic Search

A robust design for torque optimization of brushless DC spindle motors applied in a hard disk drive, using the Taguchi method, is described and illustrated in this paper. The optimal design process takes into consideration noises that arise in the manufacturing process, such as manufacturing tolerances for the stator tooth shape and variation of the rotor magnet magnetization distribution due

Teck-Seng Low; Shixin Chen; Xianke Gao

2001-01-01

207

Torque and First-Class Levers  

NSDL National Science Digital Library

This inquiry activity should be done before students have studied the operation of a first-class lever. The activity could be used when discussing simple machines or torque. Although it involves the use of a lever, the activity is not really about simple

Horton, Michael

2009-05-30

208

Voltage induced torque in magnetic tunnel junctions  

Microsoft Academic Search

A mechanism is proposed for a voltage induced torque in magnetic tunnel junctions when the magnetizations on opposite sides of the junction are not parallel to each other. By taking into account the effect of the electron–electron interaction, we found in tunnel structures the possibility of an enhanced spin switching effect that, when normalized with respect to the current, can

Z. F. Lin; S. T. Chui; L. B. Hu

2004-01-01

209

Torque-balanced vibrationless rotary coupling  

DOEpatents

This disclosure describes a torque-balanced vibrationless rotary coupling for transmitting rotary motion without unwanted vibration into the spindle of a machine tool. A drive member drives a driven member using flexible connecting loops which are connected tangentially and at diametrically opposite connecting points through a free floating ring.

Miller, Donald M. (Sunnyside, WA)

1980-01-01

210

Radiative Torques: Analytical Model And Basic Properties  

Microsoft Academic Search

We attempt to get a physical insight into grain alignment processes by studying basic properties of radiative torques (RATs). For this purpose we consider a simple toy model of a helical grain that reproduces well the basic features of RATs. The model grain consists of a reflecting spheroidal body with a reflecting mirror attached at an angle to it. Being

Thiem Hoang

2007-01-01

211

Dynamic torque measurement for automotive application  

Microsoft Academic Search

This work presents a system for the measurement and monitoring of the torque transmitted to the wheel of a moving vehicle. The transducer was built on the aluminum alloy wheel and the electronic system installed right on the center of the wheel assembly. The whole system spins with the tire, commanded by the power sent by the engine. The designed

Valner Brusamarello; Alexandre Balbinot; Luiz Carlos Gertz; André Cerviéri

2010-01-01

212

Air brake-dynamometer accurately measures torque  

NASA Technical Reports Server (NTRS)

Air brake-dynamometer assembly combines the principles of the air turbine and the air pump to apply braking torque. The assembly absorbs and measures power outputs of rotating machinery over a wide range of shaft speeds. It can also be used as an air turbine.

1965-01-01

213

The reverse-torque test: a clinical report.  

PubMed

Reverse torque to failure on implants has been studied in animals. Three implants were reverse torqued to failure in a human volunteer, with failure rates between 45 and 58 Ncm. Clinical data are presented on 404 implants examined after reverse-torque testing and loading, with no increase in failure rates. Reverse-torque testing at 20 Ncm appears to be a safe, reliable method for verifying osseointegration with pure titanium screw-shaped implants. PMID:8666448

Sullivan, D Y; Sherwood, R L; Collins, T A; Krogh, P H

1996-01-01

214

Note: Nonlinear susceptibility from high DC field torque magnetometry  

NASA Astrophysics Data System (ADS)

Torque magnetometry is a convenient technique to measure the magnetic properties of anisotropic materials. Advances in micromachining have made torque magnetometers precise and reliable even in adverse conditions such as very high magnetic fields and very low temperatures. In most applications with such magnetometers the measured torque signals are used to arrive at the linear magnetic susceptibility. In this short note we extend torque magnetometry to measure nonlinear susceptibilities and illustrate our methods with representative data on the heavy fermion compound UPt3.

Shivaram, B. S.

2014-04-01

215

Robust torque control of harmonic drive under constrained-motion  

Microsoft Academic Search

A harmonic drive is a compact, light-weight and high-ratio torque transmission device which has almost zero backlash. Its unique performance features captures the attention of designers in many industrial applications, especially in robotics. However, the torque control of harmonic drive systems is still a challenging problem for researchers. In this paper the torque control of an harmonic drive system for

H. D. Taghirad; P. R. Belanger

1997-01-01

216

A joint torque sensing technique for robots with harmonic drives  

Microsoft Academic Search

A joint torque sensing technique for robots with harmonic drives is proposed. Elasticity of harmonic drives is utilized to measure the joint torque. The technique provides joint torque sensing without reducing the stiffness of the robot and changing the mechanical structure of the joints. A finite-element analysis of flexsplines, which are flexible thin cups made from steel in harmonic drives,

Minoru Hashimoto; Yoshihide Kiyosawa; H. Hirabayashi; R. P. Paul

1991-01-01

217

A torque sensing technique for robots with harmonic drives  

Microsoft Academic Search

The authors propose a joint torque sensing technique making use of the existing structural elasticity of robots. The technique provides joint torque sensing without reducing the stiffness of the robot or changing the mechanical structure of the joints. The elasticity of the flexsplines of the harmonic drives is utilized to measure the joint torque. The flexsplines are flexible thin cups,

M. Hashimoto; Yoshihide Kiyosawa; R. P. Paul

1993-01-01

218

Ripple compensation of harmonic drive built-in torque sensing  

Microsoft Academic Search

Built-in torque sensing in Harmonic Drives enables torque sensing without assembling additional torque sensors into mechanisms where Harmonic Drives are already present. The sensing principle has been known for about ten years, but it is not widely utilized yet, mainly because of a relatively high ripple signal in the sensing output, generated by the gear operation. Ripple is difficult to

Ivan Godler; Tamotsu Ninomiya; Masashi Horiuchi; Minoru Hashimoto

1999-01-01

219

Torque sensorless control in multidegree-of-freedom manipulator  

Microsoft Academic Search

A torque sensorless control for a multi-degree-of-freedom manipulator is described. In the method, two disturbance observers are applied to each joint. One is used to realize a robust motion controller. The other is used to obtain a sensorless torque controller. A robust acceleration controller based on the disturbance observer is shown. To obtain the sensorless torque control, it is necessary

Toshiyuki Murakami; Fangming Yu; Kouhei Ohnishi

1993-01-01

220

A direct torque controller for permanent magnet synchronous motor drives  

Microsoft Academic Search

This paper presents a direct torque control scheme for permanent magnet synchronous motor (PMSM) drives, where current controllers followed by PWM or hysteresis comparator are not used. The switching table specific for a PMSM is derived. The experimental results show that the torque response is extremely fast and that the position sensor is not essential for the inner torque loop

M. F. Rahman; L. Zhong; W. Y. Hu; K. W. Lim; M. A. Rahman

1997-01-01

221

Dynamic gearbox simulation for fault diagnostics using a torque transducer  

Microsoft Academic Search

Gears are common mechanical components used to transfer torque. A gear train consists of multiple gears on multiple gear shafts with the purpose of producing an output torque or speed proportional to an input torque or speed. Gear trains are usually housed in a gearbox, which contains the gears, gear shafts, bearings, and some sort of lubrication. Gearboxes are found

Christopher Jon Bruns

2011-01-01

222

40 CFR Table 12 to Subpart Xxxx of... - Continuous Compliance With the Emission Limits for Tire Cord Production Affected Sources  

Code of Federal Regulations, 2013 CFR

...Emission Limits for Tire Cord Production Affected Sources 12 Table 12 to Subpart XXXX of Part 63 Protection of Environment...Rubber Tire Manufacturing Pt. 63, Subpt. XXXX, Table 12 Table 12 to Subpart XXXX of Part 63âContinuous...

2013-07-01

223

Specific gravity — dry matter relationship and reducing sugar changes affected by potato variety, production area and storage  

Microsoft Academic Search

The validity of the specific gravity-dry matter relationship in potato tubers is affected by factors such as variety, area of production and storage conditions. Previous work reported by Woodbury and Weinheimer (10) showed that regression coefficients for percent dry matter on specific gravity increased with storage length. Ross and co-workers (8) reported an increase in percent dry matter for a

William M. Agle; G. W. Woodbury

1968-01-01

224

Advanced glycated end-products affect HIF-transcriptional activity in renal cells.  

PubMed

Advanced glycated end-products (AGEs) are ligands of the receptor for AGEs and increase in diabetic disease. MAPK organizer 1 (Morg1) via its binding partner prolyl-hydroxylase domain (PHD)-3 presumably plays a role in the regulation of hypoxia-inducible factor (HIF)-1? and HIF-2? transcriptional activation. The purpose of this study was to analyze the influence of AGEs on Morg1 expression and its correlation to PHD3 activity and HIF-transcriptional activity in various renal cell types. The addition of glycated BSA (AGE-BSA) significantly up-regulated Morg1 mRNA levels in murine mesangial cells and down-regulated it in murine proximal tubular cells and differentiated podocytes. These effects were reversible when the cells were preincubated with a receptor for ?-AGE antibody. AGE-BSA treatment induced a relocalization of the Morg1 cellular distribution compared with nonglycated control-BSA. Analysis of PHD3 activity demonstrated an elevated PHD3 enzymatic activity in murine mesangial cells but an inhibition in murine proximal tubular cells and podocytes after the addition of AGE-BSA. HIF-transcriptional activity was also affected by AGE-BSA treatment. Reporter gene assays and EMSAs showed that AGEs regulate HIF- transcriptional activity under nonhypoxic conditions in a cell type-specific manner. In proximal tubular cells, AGE-BSA stimulation elevated mainly HIF-1? transcriptional activity and to a lesser extent HIF-2?. We also detected an increased expression of the HIF-1? and the HIF-2? proteins in kidneys from Morg1 heterozygous (HZ) placebo mice compared with the Morg1 wild-type (WT) placebo-treated mice, and the HIF-1? protein expression in the Morg1 HZ streptozotocin-treated mice was significantly higher than the WT streptozotocin-treated mice. Analysis of isolated mesangial cells from Morg1 HZ (±) and WT mice showed an inhibited PHD3 activity and an increased HIF-transcriptional activity in cells with only one Morg1 allele. These findings are important for a better understanding of the molecular mechanisms of diabetic nephropathy. PMID:24030251

Bondeva, Tzvetanka; Heinzig, Juliane; Ruhe, Carola; Wolf, Gunter

2013-11-01

225

Rib Torque Does Not Assist Resting Tidal Expiration or Most Conversational Speech Expiration  

ERIC Educational Resources Information Center

Purpose: This research note discusses a common misconception in speech science and speech-language pathology textbooks that rib torque (i.e., "rotational stress") assists resting tidal expiration and conversational speech production. Method: The nature of this misconception is considered. Conclusion: An alternate conceptualization is offered that…

Hixon, Thomas J.

2006-01-01

226

Torque generated by the flagellar motor of Escherichia coli.  

PubMed Central

Cells of the bacterium Escherichia coli were tethered and spun in a high-frequency rotating electric field at a series of discrete field strengths. This was done first at low field strengths, then at field strengths generating speeds high enough to disrupt motor function, and finally at low field strengths. Comparison of the initial and final speed versus applied-torque plots yielded relative motor torque. For backward rotation, motor torque rose steeply at speeds close to zero, peaking, on average, at about 2.2 times the stall torque. For forward rotation, motor torque remained approximately constant up to speeds of about 60% of the zero-torque speed. Then the torque dropped linearly with speed, crossed zero, and reached a minimum, on average, at about -1.7 times the stall torque. The zero-torque speed increased with temperature (about 90 Hz at 11 degrees C, 140 Hz at 16 degrees C, and 290 Hz at 23 degrees C), while other parameters remained approximately constant. Sometimes the motor slipped at either extreme (delivered constant torque over a range of speeds), but eventually it broke. Similar results were obtained whether motors broke catastrophically (suddenly and completely) or progressively or were de-energized by brief treatment with an uncoupler. These results are consistent with a tightly coupled ratchet mechanism, provided that elastic deformation of force-generating elements is limited by a stop and that mechanical components yield at high applied torques.

Berg, H C; Turner, L

1993-01-01

227

40 CFR 63.5795 - How do I know if my reinforced plastic composites production facility is a new affected source or...  

Code of Federal Regulations, 2013 CFR

...composites production facility is a new affected source or an existing affected source? 63.5795 Section 63.5795 Protection...EMISSION STANDARDS FOR HAZARDOUS AIR POLLUTANTS FOR SOURCE CATEGORIES (CONTINUED) National...

2013-07-01

228

Throwing darts utilizes the interaction torque of the elbow joint.  

PubMed

Acquiring the skillful movements of experts is a difficult task in many fields. If we find quantitative indices of skillful movement, we can develop an adaptive training system using the indices. We focused on throwing darts in our previous study. It was found that optimization criteria of sum of squared joint torque changes over time was negatively correlated with subject's scores, suggesting that the experts optimally controlled the shoulder elevations and rotation around the elbow joint in terms of dynamics. In this study, we investigate the relationship between the skill level of subjects and their utilization joint torque components such as the muscular torque, interaction torque and gravity torque. It is shown found that the sum of squared joint torque components of the subjects correlates with their scores, suggesting that the subjects who can take higher scores utilize the interaction torque of the elbow joint without shoulder displacement. PMID:22254551

Tamei, Tomoya; Obayashi, Chihiro; Shibata, Tomohiro

2011-01-01

229

Does artificial snow production affect soil and vegetation of ski pistes? A review  

Microsoft Academic Search

The production of artificial snow and the use of snow additives in ski resorts have increased considerably during the last 20 years. Their ecological consequences are the subject of environmental concerns. This review compiles studies about the ecological implications of ski pistes preparation in general and of artificial snow production. The main direct impacts of ski piste preparation on the

Christian Rixen; Veronika Stoeckli; Walter Ammann

2003-01-01

230

Factors affecting the development of two fermented milk products in Zimbabwe  

Microsoft Academic Search

Summary The effect of container, of pasteurization and of using starter cultures were studied with respect to lactic acid production, lactic acid bacterial counts, total microbial counts and the acceptability of two traditionally- and industrially-fermented milk products of Zimbabwe. Earthenware pots were better containers for the fermentation of pasteurized milk than glass containers. Pasteurization decreased both lactic acid bacteria counts

Sara Feresu; M. I. Muzondo

1989-01-01

231

Key factors affecting microbial anode potential in a microbial electrolysis cell for H 2 production  

Microsoft Academic Search

In order to optimize operations of microbial electrolysis cell (MEC) for hydrogen production, microbial anode potential (MAP) was analyzed as a function of factors in biofilm anode system, including pH, substrate and applied voltage. The results in “H” shape reactor showed that MAP reflected the information when any factor became limiting for hydrogen production. Commonly, hydrogen generation started around anode

Aijie Wang; Wenzong Liu; Nanqi Ren; Jizhong Zhou; Shaoan Cheng

2010-01-01

232

Does the shelterwood method to regenerate oak forests affect acorn production and predation?  

Microsoft Academic Search

The shelterwood system is one of the primary methods currently used to encourage regeneration of oak forests; yet, little is known about its influence on acorn production and predation. We compared acorn production, and predation by insects and mammals in stands of red oak (Quercus rubra L.) that were regenerated by the shelterwood method (50% canopy removal) to that of

M. I. Bellocq; C. Jones; D. C. Dey; J. J. Turgeon

2005-01-01

233

Soil Management and Landscape Variability Affects Field-Scale Cotton Productivity  

Microsoft Academic Search

A better understanding of interactions between soil management and landscape variability and their effects on cotton (Gossypium hirsutum L.) productivity is needed for precision management. We assessed management practices and landscape variability effects on seed cotton yield in a 9-ha, Alabama field (Typic and Aquic Paleu- dults) during 2001-2003. We hypothesize that landscapes have major effects on cotton productivity, but

J. A. Terra; Joey N. Shaw; D. W. Reeves; R. L. Raper; E. van Santen; E. B. Schwab; P. L. Mask

2006-01-01

234

Altering n-3 to n-6 polyunsaturated fatty acid ratios affects prostaglandin production by ovine uterine endometrium.  

PubMed

Consumption of n-3 polyunsaturated fatty acids (PUFAs) is considered beneficial to health but effects on fertility remain uncertain. This study investigated the effect of n-3 PUFA supplementation on endometrial prostaglandin (PG) production. Ovine uterine endometrial cells were cultured to confluence in DMEM/F12 medium containing 10% foetal bovine serum. Stromal and epithelial cell populations were confirmed by immunocytochemistry. Cultures were supplemented with 0, 20 or 100 ?M of ?-linolenic acid (ALA), stearidonic acid (SDA), eicosapentaenoic acid (EPA) with lipopolysaccharide (LPS) at 0 and 0.1 ?g/ml, or different combinations of EPA with arachidonic acid (AA) in serum-free medium for 24h. PGs were quantified using radioimmunoassay and PG-endoperoxide synthase (PTGS) isoforms, PGE and PGF synthase (microsomal PGES1 and PGFS) mRNAs by qPCR. LPS increased PGE2 production significantly without changing PGF2? production, causing increased PGE2:PGF2? ratios. ALA and SDA increased PGE2, PGF2? and PGE2:PGF2? ratios (P<0.05-0.01) while EPA alone did not affect PG generation. AA significantly stimulated PTGS1 and PTGS2 mRNA expression and PGE2 and PGF2? production (P<0.01). The stimulatory effect of AA was attenuated by up to 80% (P<0.05) when AA was combined with EPA. The PGE2:PGF2? ratio was not affected by AA or EPA alone, but increased when these two PUFAs were combined (P<0.05). SDA and EPA decreased PTGS1 mRNA expression (P<0.05) but did not alter PTGS2 expression. EPA and AA up-regulated mPGES1 expression (P<0.05) without affecting PGFS expression. Since AA is preferentially incorporated in uterine endometrium to produce 2-series PGs, alteration of PG production by EPA may affect many reproductive processes. PMID:24287151

Cheng, Zhangrui; Abayasekara, D Robert E; Ward, Freya; Preece, Daniel M W; Raheem, Kabir A; Wathes, D Claire

2013-12-01

235

Effect of series elasticity on isokinetic torque-angle relationship in humans.  

PubMed

The influence of muscle series elasticity on the relationship between torque and joint angle during dynamic contractions was studied. The torque-angle relationship during the maximal isokinetic knee extension was determined for six male subjects (25-45 years) at 0.52, 1.05, 1.57, 2.09, 2.62, 3.49 rad/s. The knee joint angle at which peak torque was observed showed a systematic shift to more extended positions, i.e., the quadriceps muscle-tendon unit length became shorter as the velocity increased [from 1.01 (0.12) rad (0.52 rad/s) to 0.75 (0.14) rad (3.49 rad/s), mean (SD)]. The corresponding difference in muscle-tendon unit length between 0.52 and 3.49 rad/s, estimated from the angle shift at peak torque and the moment arm length change of the quadriceps muscles, was 9 (4) mm. The relationship between estimated changes in muscle-tendon unit length and muscle force of the vastus lateralis and intermedius (VLI) over the seven velocities (including isometric contraction, 0 rad/s) coincided with the load-elongation properties of the series elastic component of VLI, determined separately in vivo by ultrasonography when the same subjects performed a ramp isometric knee extension. The results suggest that the torque-angle relationship is affected by the interaction between contractile and elastic components, and that peak torque angle shift is attributable to the elongation of tendinous tissues as a function of force applied to them. PMID:12172877

Kawakami, Y; Kubo, K; Kanehisa, H; Fukunaga, T

2002-08-01

236

Interannual Atmospheric Torque and ENSO: Where is the Polar Motion Signal?  

NASA Astrophysics Data System (ADS)

Climate variability on interannual time scales is dominated by the El Nino / Southern Oscillation (ENSO), an ocean-atmosphere instability originating in the equatorial Pacific. ENSO has a strong signature in length-of-day (LOD), which can be accounted for almost entirely by atmospheric angular momentum (AAM) variations. It has been noted, however, that ENSO effects on polar motion (PM) are much weaker and hard to detect. In this study, we use the torque approach to explore Earth-atmosphere interaction associated with ENSO, and seek to understand why the large atmospheric fluctuations arising from ENSO are not effective in exciting PM variations. PM is affected by atmospheric torques acting in the equatorial plane, which arise largely from gravitational and surface pressure interactions with the Earth's bulge. Using the inverted barometer (IB) approximation for the effect of atmospheric loading on the ocean, we find that the bulge torque exhibits significant coherence with the Southern Oscillation Index (SOI), confirming that the atmosphere acts to force PM in association with ENSO. While the bulge torque is correlated with geodetic excitation at high (sub-annual) frequencies, however, the two series are not coherent at longer (interannual) periods, presumably due to the effects of other excitation sources (e.g. oceans) on these time scales. Local (i.e., non-bulge) torques are also found to be coherent with the SOI, in particular due to the interaction of surface pressure anomalies with the large-scale topography of Antarctica. The local torques can be directly related to wind term anomalies of equatorial AAM, largely associated with extratropical vortices located over the Pacific ocean.

Marcus, S. L.; de Viron, O.; Dickey, J. O.

2003-12-01

237

How can farming intensification affect the environmental impact of milk production?  

PubMed

The intensification process of the livestock sector has been characterized in recent decades by increasing output of product per hectare, increasing stocking rate, including more concentrated feed in the diet, and improving the genetic merit of the breeds. In dairy farming, the effects of intensification on the environmental impact of milk production are not completely clarified. The aim of the current study was to assess the environmental impacts of dairy production by a life cycle approach and to identify relations between farming intensity and environmental performances expressed on milk and land units. A group of 28 dairy farms located in northern Italy was involved in the study; data collected during personal interviews of farmers were analyzed to estimate emissions (global warming potential, acidification, and eutrophication potentials) and nonrenewable source consumption (energy and land use). The environmental impacts of milk production obtained from the life cycle assessment were similar to those of other recent studies and showed high variability among the farms. From a cluster analysis, 3 groups of farms were identified, characterized by different levels of production intensity. Clusters of farms showed similar environmental performances on product basis, despite important differences in terms of intensification level, management, and structural characteristics. Our study pointed out that, from a product perspective, the most environmentally friendly way to produce milk is not clearly identifiable. However, the principal component analysis showed that some characteristics related to farming intensification, such as milk production per cow, dairy efficiency, and stocking density, were negatively related to the impacts per kilogram of product, suggesting a role of these factors in the mitigation strategy of environmental burden of milk production on a global scale. Considering the environmental burden on a local perspective, the impacts per hectare were positively associated with the intensification level. PMID:24792806

Bava, L; Sandrucci, A; Zucali, M; Guerci, M; Tamburini, A

2014-07-01

238

A dynamic method for magnetic torque measurement  

NASA Technical Reports Server (NTRS)

In a magnetic suspension system, accurate force measurement will result in better control performance in the test section, especially when a wider range of operation is required. Although many useful methods were developed to obtain the desired model, however, significant error is inevitable since the magnetic field distribution of the large-gap magnetic suspension system is extremely nonlinear. This paper proposed an easy approach to measure the magnetic torque of a magnetic suspension system using an angular photo encoder. Through the measurement of the velocity change data, the magnetic torque is converted. The proposed idea is described and implemented to obtain the desired data. It is useful to the calculation of a magnetic force in the magnetic suspension system.

Lin, C. E.; Jou, H. L.

1994-01-01

239

Six component robotic force-torque sensor  

NASA Technical Reports Server (NTRS)

The results of a two-phase contract studying the feasibility of a miniaturized six component force-torque sensor and development of a working laboratory system were described. The principle of operation is based upon using ultrasonic pulse-echo ranging to determine the position of ultrasonic reflectors attached to a metal or ceramic cover plate. Because of the small size of the sensor, this technology may have application in robotics, to sense forces and torques at the finger tip of a robotic end effector. Descriptions are included of laboratory experiments evaluating materials and techniques for sensor fabrication and of the development of support electronics for data acquisition, computer interface, and operator display.

Grahn, Allen R.; Hutchings, Brad L.; Johnston, David R.; Parsons, David C.; Wyatt, Roland F.

1987-01-01

240

Torque Transmission Device at Zero Leakage  

NASA Technical Reports Server (NTRS)

In a few critical applications, mechanical transmission of power by rotation at low speed is required without leakage at an interface. Herein we examine a device that enables torque to be transmitted across a sealed environmental barrier. The barrier represents the restraint membrane through which the torque is transmitted. The power is transferred through elastic deformation of a circular tube into an elliptical cross-section. Rotation of the principle axis of the ellipse at one end results in a commensurate rotation of an elliptical cross section at the other end of the tube. This transfer requires no rigid body rotation of the tube allowing a membrane to seal one end from the other. Both computational and experimental models of the device are presented.

Hendricks, R. C.; Mullen, R. L.

2005-01-01

241

The Influence of Induced Positive Affect and Design Experience on Aesthetic Responses to New Product Designs  

Microsoft Academic Search

This experiment found that positive affect, induced by a gift of a small bag of candy (not consumed), enhanced ratings of the visual appeal of a set of six digital cameras by male participants untrained and trained in principles of design theory, as compared to control groups who did not receive candy (N = 10 per group). The number of

Joep Frens; Kees Overbeeke

2008-01-01

242

Volatile production by Aspergillus versicolor as a possible cause of odor in houses affected by fungi  

Microsoft Academic Search

Aspergillus versicolor, which has been isolated from several mould affected houses was shown by laboratory studies under axenic conditions to produce several specific volatile compounds on water agar. These compounds were not produced by the fungus when grown on a rich malt extract medium or on several synthetic media. The volatile compounds were analysed by GC-MS. The majority of the

Jonny Bjurman; Jan Kristensson

1992-01-01

243

Gamma hydroxybutyric acid (GHB) concentrations in humans and factors affecting endogenous production  

Microsoft Academic Search

The endogenous nature of the drug of abuse gamma hydroxybutyric acid (GHB) has caused various interpretative problems for toxicologists. In order to obtain data for the presence of endogenous GHB in humans and to investigate any factors that may affect this, a volunteer study was undertaken. The GHB concentrations in 119 urine specimens from GHB-free subjects and 25 urine specimens

Simon P Elliott

2003-01-01

244

Physicochemical factors differentially affect the biomass and bacteriocin production by bovine Enterococcus mundtii CRL1656.  

PubMed

Bovine Enterococcus mundtii CRL1656 (Centro de Referencia para Lactobacilos Culture Collection) produces an anti-Listeria and anti-Streptococcus dysgalactiae bacteriocin identified as mundticin CRL1656. The strain and its bacteriocin are candidates to be included in a beneficial product to prevent bovine mastitis as an alternative to antimicrobial agents. To optimize the production of biomass and mundticin CRL1656 by E. mundtii CRL1656, a complete 3×2(4) factorial design was applied. The effect of culture medium, initial pH, inoculum size, incubation temperature, and agitation conditions on biomass and bacteriocin production was evaluated simultaneously. Growth parameters were determined using the modified Gompertz model. A nonlinear model was used to estimate the effects of the variables on growth parameters. Bacteriocin production was analyzed using a linear mixed model. Optimal biomass and mundticin CRL1656 production by E. mundtii CRL1656 were obtained in different conditions. Maximal growth was recorded in autolyzed yeast, peptone, tryptone, Tween 80, and glucose or M17 broths, pH 6.5, 5.0% inoculum, 30°C, with agitation. However, bacteriocin titers were higher in autolyzed yeast, peptone, tryptone, Tween 80, and glucose or de Man-Rogosa-Sharpe (MRS) broths, pH 6.5, 30°C, both with or without agitation. Knowledge of the optimum conditions for growth and bacteriocin production of E. mundtii CRL1656 will allow the obtainment of high levels of biomass and mundticin CRL1656 as bioingredients of potential products to prevent bovine mastitis. PMID:24359825

Espeche, M Carolina; Tomás, M Silvina Juárez; Wiese, Birgitt; Bru, Elena; Nader-Macías, M E Fátima

2014-02-01

245

An ironless armature brushless torque motor  

NASA Technical Reports Server (NTRS)

A high torque motor with improved servo mechanism is reported. Armature windings are cast into an epoxy cylinder and armature conductors are integrally cast with an aluminum mounting ring which provides thermal conductance directly into the structure. This configuration eliminates magnetic hysteresis because there is no relative motion between the rotating magnetic field and any stationary iron. The absence of destabilization forces provides a fast electrical response compared with a typical torquer of conventional construction.

Studer, P. A.

1973-01-01

246

Liquid and Solid Meal Replacement Products Differentially Affect Postprandial Appetite and Food Intake in Older Adults  

PubMed Central

Liquid and solid foods are documented to elicit differential appetitive and food intake responses. This study was designed to assess the influences of liquid vs solid meal replacement products on postprandial appetite ratings and subsequent food intake in healthy older adults. This study used a randomized and crossover design with two 1-day trials (1 week between trials), and 24 adults (12 men and 12 women) aged 50 to 80 years with body mass index (calculated as kg/m2) between 22 and 30 participated. After an overnight fast, the subjects consumed meal replacement products as either a beverage (liquid) or a bar (solid). The meal replacement products provided 25% of each subject's daily estimated energy needs with comparable macro-nutrient compositions. Subjects rated their appetite on a 100 mm quasilogarithmic visual analog scale before and 15, 30, 45, 60, 90, 120, and 150 minutes after consuming the meal replacement product. At minute 120, each subject consumed cooked oatmeal ad libitum to a “comfortable level of fullness.” Postprandial composite (area under the curve from minute 15 to minute 120) hunger was higher (P=0.04) for the liquid vs solid meal replacement products and desire to eat (P=0.15), preoccupation with thoughts of food (P=0.07), and fullness (P=0.25) did not differ for the liquid vs solid meal replacement products. On average, the subjects consumed 13.4% more oatmeal after the liquid vs solid (P=0.006) meal replacement product. These results indicate that meal replacement products in liquid and solid form do not elicit comparable appetitive and ingestive behavior responses and that meal replacement products in liquid form blunt the postprandial decline in hunger and increase subsequent food intake in older adults.

Stull, April J.; Apolzan, John W.; Thalacker-Mercer, Anna E.; Iglay, Heidi B.; Campbell, Wayne W.

2008-01-01

247

Nature and measurements of torque ripple of permanent-magnet adjustable-speed motors  

SciTech Connect

Torque ripple of permanent-magnet motors can be classified into four types depending on the nature of their origin. The four types are pulsating torque, fluctuating torque, reluctance cogging torque, and inertia and mechanical system torque. Pulsating torques are inherently produced by the trapezoidal back-emf`s and trapezoidal currents used in certain permanent-magnet adjustable-speed motors. The torque ripples caused by pulsating torques may be reduced by purposely produced fluctuating counter torques. Air-gap torque measurements are conducted on a sample motor. Experimental results agree with theoretical expectations.

Hsu, J.S.; Scoggins, B.P.; Scudiere, M.B.; Marlino, L.D.; Adams, D.J.; Pillay, P.

1995-08-01

248

Systems, methods and computer program products for assessing delivery affectivity in quality function deployment  

US Patent & Trademark Office Database

Systems, methods, and computer program products are provided for a quantifiable assessment of the delivery effectiveness of Quality Function Deployment (QFD) planning designs. In this regard, present embodiments provide quantifiable metrics that help a key stakeholder, such as a product or service provider, determine the level of success for each design requirement or Critical-To-Quality (CTQ) attribute defined in the QFD design process. Thus, based on presently described embodiments, the stakeholder can assess how well the deployment of their product or service met the original defined CTQs and/or design requirements and which CTQs and which design requirements related to those CTQs should garner further attention to ensure that the CTQ meets its objective, which in turn allows for the opportunity for the highest possible customer satisfaction with the new or re-designed product, process or service.

2013-10-01

249

Characterization of a purF operon mutation which affects colicin V production.  

PubMed Central

A mini-Tn10-kan insertion mutation identified a gene in the chromosome of Escherichia coli required for colicin V production from plasmid pColV-K30. With the complete restriction map of E. coli, the mutation was rapidly mapped to 50.0 min, within the purF operon. Sequence analysis showed that the insertion occurred in a gene with no previously known function which is located directly upstream of purF. We designated this gene cvpA for colicin V production. The mutant requires adenine for growth, probably because of a polar effect on purF expression. However, an adenine auxotroph showed no defect in colicin V production, suggesting that the cvpA mutation is responsible for the effect on colicin V production. Two possible models of cvpA1 allele function are discussed. Images

Fath, M J; Mahanty, H K; Kolter, R

1989-01-01

250

Affects of Provider Type on Patient Satisfaction, Productivity and Cost Efficiency.  

National Technical Information Service (NTIS)

The purpose of this one year retrospective quantitative study is to determine if the type of provider (physician, nurse practitioner, and physician assistant) influences patient satisfaction and productivity. 104,013 Army beneficiaries who visited their P...

T. Foster

2006-01-01

251

The Spin Torque Lego - from spin torque nano-devices to advanced computing architectures  

NASA Astrophysics Data System (ADS)

Spin transfer torque (STT), predicted in 1996 [1], and first observed around 2000, brought spintronic devices to the realm of active elements. A whole class of new devices, based on the combined effects of STT for writing and Giant Magneto-Resistance or Tunnel Magneto-Resistance for reading has emerged. The second generation of MRAMs, based on spin torque writing : the STT-RAM, is under industrial development and should be out on the market in three years. But spin torque devices are not limited to binary memories. We will rapidly present how the spin torque effect also allows to implement non-linear nano-oscillators, spin-wave emitters, controlled stochastic devices and microwave nano-detectors. What is extremely interesting is that all these functionalities can be obtained using the same materials, the exact same stack, simply by changing the device geometry and its bias conditions. So these different devices can be seen as Lego bricks, each brick with its own functionality. During this talk, I will show how spin torque can be engineered to build new bricks, such as the Spintronic Memristor, an artificial magnetic nano-synapse. I will then give hints on how to assemble these bricks in order to build novel types of computing architectures, with a special focus on neuromorphic circuits. [4pt] [1] J. C. Slonczewski, J. Magn. Magn. Mater. 159, 1 (1996) & L. Berger, Phys. Rev. B 54, 9353 (1996)

Grollier, Julie

2013-03-01

252

Factors affecting quality and post-production life of Exacum affine  

Microsoft Academic Search

Two cultivars of Exacum affine, White Princess and Royal Dane, were grown under supplementary light conditions (70 and 100?molm?2s?1). The higher light intensity reduced the production time and resulted in increased flower development during the post-production period in an interior environment. To test ethylene responses, the plants were sprayed with the anionic silver thiosulphate complex (STS) and then exposed to

Margrethe Serek; Louisa Trolle

2000-01-01

253

Screening of yeasts for production of xylitol fromd-xylose and some factors which affect xylitol yield in Candida guilliermondii  

Microsoft Academic Search

Summary The ability to convertd-xylose to xylitol was screened in 44 yeasts from five genera. All but two of the strains produced some xylitol with varying rates and yields. The best xylitol producers were localized largely in the speciesCandida guilliermondii andC. tropicalis. Factors affecting xylitol production by a selectedC. guilliermondii strain, FTI-20037, were investigated. The results showed that xylitol yield

Maria F. S. Barbosa; Maria B. de Medeiros; Ismael M. de Mancilha; Henry Schneider; Hung Lee

1988-01-01

254

Factors affecting the polycyclic aromatic hydrocarbon content of cereals, fats and other food products  

Microsoft Academic Search

Factors affecting polycyclic aromatic hydrocarbon (PAH) concentrations in oils and fats, cereals and related foodstuffs have been investigated. Levels of PAHs were low in retail fish and animal?derived oils and fats, such as butter, where the mean benzo(a)pyrene concentration was 0.06 ?g\\/kg. Higher and more variable amounts were present in retail vegetable oils for which the mean level of benzo(a)pyrene

M. J. Dennis; R. C. Massey; G. Cripps; I. Venn; N. Howarth; G. Lee

1991-01-01

255

Bioprospecting for microbial products that affect ice crystal formation and growth  

Microsoft Academic Search

At low temperatures, some organisms produce proteins that affect ice nucleation, ice crystal structure, and\\/or the process\\u000a of recrystallization. Based on their ice-interacting properties, these proteins provide an advantage to species that commonly\\u000a experience the phase change from water to ice or rarely experience temperatures above the melting point. Substances that bind,\\u000a inhibit or enhance, and control the size, shape,

Brent C. Christner

2010-01-01

256

Maximal peak torque as a predictor of angle-specific torques of hamstring and quadriceps muscles in man.  

PubMed

This study assessed the relationship between the isokinetic peak torque (PT) (speed of movement 1.05 and 3.14 rads-1) and the angle-specific torques (ASTs) at 0.26 and 1.31 rad of knee flexion in multiple contractions of the quadriceps and hamstrings in 70 individuals with a chronic anterior cruciate ligament (ACL) insufficiency and 78 individuals with a chronic medial collateral ligament (MCL) insufficiency in one knee. At every test speed, the Pearson product moment correlation coefficients (r) between the PT and ASTs were highly significant (P less than 0.001) in the uninjured knees (r = 0.61-0.93) as well as in the knees with ACL (r = 0.61-0.87) and MCL (r = 0.74-0.91) insufficiency. In addition, in both groups the majority of the correlation coefficients exceeded 0.80, which is generally regarded as the threshold for the relationship to be considered clinically significant. Furthermore, using regression analysis, both extremities showed completely non-systematic distribution of the residuals. It is concluded that in healthy knees or knees with ACL or MCL insufficiency, the predictability of ASTs from PT was good, and, therefore, that AST analyses may offer little additional information about thigh muscle function to that obtained from a simpler and more commonly used measurement, the PT analysis. PMID:1748100

Kannus, P; Järvinen, M; Lehto, M

1991-01-01

257

Relationship between Peak Torque and Angle-specific Torques in an Isokinetic Contraction of Normal and Laterally Unstable Knees.  

PubMed

This study assessed the relationship between the isokinetic peak torque (PT) (speed of movement, 60 degrees /sec and 180 degrees /sec) and the angle-specific torques (ASTs) at 15 and 75 degrees of knee flexion in multiple contractions of the quadriceps and hamstrings in 21 subjects having a chronic lateral collateral ligament (LCL) insufficiency in one knee. At every test speed, the Pearson product moment (r) correlation coefficients between the PT and ASTs were highly significant (p < 0.001) in the uninjured (r = 0.66-0.92) as well as in the LCL insufficient (r = 0.78-0.88) knees. In both extremities, the majority of the correlation coefficients exceeded 0.80, which was the threshold set before the study for the coefficients to be exceeded before the relationship could be considered clinically important. Using regression analysis, both extremities showed completely nonsystematic distribution of the residuals. In conclusion, concerning healthy or LCL-insufficient knees, the correlations between PT and ASTs were high and consistent. Therefore, AST analyses may offer little additional information about thigh muscle function to that obtained through a simpler and more commonly used measurement, the PT analysis. J Orthop Sports Phys Ther 1991;13(2):89-94. PMID:18796855

Kannus, P

1991-01-01

258

Evolution of binary black holes in self gravitating discs. Dissecting the torques  

NASA Astrophysics Data System (ADS)

Context. Massive black hole binaries, formed in galaxy mergers, are expected to evolve in dense circumbinary discs. Understanding of the disc-binary coupled dynamics is vital to assess both the final fate of the system and its potentially observable features. Aims: Aimed at understanding the physical roots of the secular evolution of the binary, we study the interplay between gas accretion and gravity torques in changing the binary elements (semi-major axis and eccentricity) and its total angular momentum budget. We pay special attention to the gravity torques, by analysing their physical origin and location within the disc. Methods: We analysed three-dimensional smoothed particle hydrodynamics simulations of the evolution of initially quasi-circular massive black hole binaries (BHBs) residing in the central hollow (cavity) of massive self-gravitating circumbinary discs. We performed a set of simulations adopting different thermodynamics for the gas within the cavity and for the "numerical size" of the black holes. Results: We show that (i) the BHB eccentricity growth found in our previous work is a general result, independent of the accretion and the adopted thermodynamics; (ii) the semi-major axis decay depends not only on the gravity torques but also on their subtle interplay with the disc-binary angular momentum transfer due to accretion; (iii) the spectral structure of the gravity torques is predominately caused by disc edge overdensities and spiral arms developing in the body of the disc and, in general, does not reflect directly the period of the binary; (iv) the net gravity torque changes sign across the BHB corotation radius (positive inside vs negative outside) We quantify the relative importance of the two, which appear to depend on the thermodynamical properties of the instreaming gas, and which is crucial in assessing the disc-binary angular momentum transfer; (v) the net torque manifests as a purely kinematic (non-resonant) effect as it stems from the low density cavity, where the material flows in and out in highly eccentric orbits. Conclusions: Both accretion onto the black holes and the interaction with gas streams inside the cavity must be taken into account to assess the fate of the binary. Moreover, the total torque exerted by the disc affects the binary angular momentum by changing all the elements (mass, mass ratio, eccentricity, semimajor axis) of the black hole pair. Commonly used prescriptions equating tidal torque to semi-major axis shrinking might therefore be poor approximations for real astrophysical systems.

Roedig, C.; Sesana, A.; Dotti, M.; Cuadra, J.; Amaro-Seoane, P.; Haardt, F.

2012-09-01

259

Different blood and sugar feeding regimes affect the productivity of Anopheles arabiensis colonies (Diptera: Culicidae).  

PubMed

The success of the sterile insect technique for the management of mosquito populations depends on the release of large numbers of competitive sterile male insects. Sustainable mosquito production can only be obtained when proper mass-rearing equipment and adequate methods are available, including those to feed blood to the female mosquitoes. The blood feeding apparatus Hemotek consists of a small aluminum plate to which a collagen membrane is fixed and filled with blood kept warm by an electric heating element. A larger aluminum plate was developed to feed a larger number of female mosquitoes with blood that is kept at a constant temperature. The effect of different blood feeding regimes (feeding frequency and time the blood is kept in the Hemotek) and sugar deprivation before blood feeding on egg production of female Anopheles arabiensis Patton was tested. Egg production was higher when blood was offered to the mosquitoes every day as compared with every 2 or 4 d. Sugar deprivation for 7 h before blood feeding enhanced egg production by 50% compared with female mosquitoes that had continuous access to sugar. Neither male nor female survival was impaired. Finally, we showed that the same blood could be kept warm and used over several hours to feed mosquitoes in multiple cages without any impact on egg production or hatch rate. Being able to use the same blood over extended periods would save considerable time, handling, and funds. PMID:23540122

Damiens, D; Soliban, S M; Balestrino, F; Alsir, R; Vreysen, M J B; Gilles, J R L

2013-03-01

260

How polyamine synthesis inhibitors and cinnamic acid affect tropane alkaloid production.  

PubMed

Hairy roots of Brugmansia candida produce the tropane alkaloids scopolamine and hyoscyamine. In an attempt to divert the carbon flux from competing pathways and thus enhance productivity, the polyamine biosynthesis inhibitors cyclohexylamine (CHA) and methylglyoxal-bis-guanylhydrazone (MGBG) and the phenylalanine-ammonia-lyase inhibitor cinnamic acid were used. CHA decreased the specific productivity of both alkaloids but increased significantly the release of scopolamine (approx 500%) when it was added in the mid-exponential phase. However, when CHA was added for only 48 h during the exponential phase, the specific productivity of both alkaloids increased (approx 200%), favoring scopolamine. Treatment with MGBG was detrimental to growth but promoted release into the medium of both alkaloids. However, when it was added for 48 h during the exponential phase, MGBG increased the specific productivity (approx 200%) and release (250- 1800%) of both alkaloids. Cinnamic acid alone also favored release but not specific productivity. When a combination of CHA or MGBG with cinnamic acid was used, the results obtained were approximately the same as with each polyamine biosynthesis inhibitor alone, although to a lesser extent. Regarding root morphology, CHA inhibited growth of primary roots and ramification. However, it had a positive effect on elongation of lateral roots. PMID:17416978

Marconi, Patricia L; Alvarez, María A; Pitta-Alvarez, Sandra I

2007-01-01

261

Intrinsic domain wall flexing from current-induced spin torque  

NASA Astrophysics Data System (ADS)

Spin torque generated by coherent carrier transport in domain walls [1] is a major component in the development of spintronic devices [2]. We model spin torque in N'eel walls [3] using a piecewise linear transfer-matrix method [4] to calculate spin torque on interior wall segments. For a ? wall with a total positive torque (current left-to-right), we find the largest positive and negative spin torques left of the central region, 4-5 orders of magnitude larger than the center. The wall's rightward push comes from the back of the wall; all other significant regions pull to the left. Adding a second wall (both walls with positive total torque) changes the first wall little, but produces spin torques in the second wall with large canceling torques on the left, and the push rightward from a smaller torque on the right. The gradient of torque across the wall generates an intrinsic domain wall flexing (distinct from extrinsic wall flexing from pinning centers [5]). Work supported by an ARO MURI.[4pt] [1] M. Yamanouchi et al., Nature 428, 539 (2004).[0pt] [2] S. Parkin et al., Science 320, 190 (2008)[0pt] [3] G. Vignale and M. Flatt'e, Phys. Rev. Lett. 89, 098302 (2002)[0pt] [4] E. Golovatski and M. Flatt'e, Phys. Rev. B, 84, 115210 (2011)[0pt] [5] A. Balk et al., Phys. Rev. Lett. 107, 077205 (2011).

Golovatski, Elizabeth; Flatté, Michael

2012-02-01

262

Differences in elbow flexion torque measured concentrically, eccentrically, and isometrically.  

PubMed

The purposes of this study were to describe torque-velocity relationships during concentric, eccentric, and isometric testing of elbow flexor muscles and to determine test-retest reliability of a specific isokinetic testing protocol. Thirty healthy women were tested using an isokinetic dynamometer at velocities of 0 degrees, 30 degrees, 120 degrees, and 210 degrees/sec. Reliability was assessed in 20 of the subjects by retesting concentric and eccentric torques at 30 degrees and 120 degrees/sec after a 30-minute rest interval. The highest torque from three maximal efforts was considered to be peak torque. Mean eccentric peak torque was greater than either isometric or concentric peak torque; as isokinetic test velocity increased, the differences between concentric and eccentric torques became larger. Intraclass correlation coefficients ranged from .72 to .83, indicating lack of consistency between test and retest torques. Consecutive concentric-eccentric testing and lack of mechanical stabilization might have contributed to test-retest variability and to the relatively small differences between concentric and eccentric torques. Continued study of reliability of isokinetic testing protocols and further investigation of concentric-eccentric torque-velocity relationships are advocated. PMID:3615588

Griffin, J W

1987-08-01

263

Submerged Conidiation and Product Formation by Aspergillus niger at Low Specific Growth Rates Are Affected in Aerial Developmental Mutants ?  

PubMed Central

Exposure to an aerial environment or severe nutrient limitation induces asexual differentiation in filamentous fungi. Submerged cultivation of Aspergillus niger in carbon- and energy-limited retentostat cultures both induces and fuels conidiation. Physiological and transcriptomic analyses have revealed that this differentiation strongly affects product formation. Since conidiation is inherent in the aerial environment, we hypothesized that product formation near zero growth can be influenced by affecting differentiation or development of aerial hyphae in general. To investigate this idea, three developmental mutants (?fwnA, scl-1, and scl-2 mutants) that have no apparent vegetative growth defects were cultured in maltose-limited retentostat cultures. The secondary-metabolite profile of the wild-type strain defined flavasperone, aurasperone B, tensidol B, and two so far uncharacterized compounds as associated with conidium formation, while fumonisins B2, B4, and B6 were characteristic of early response to nutrient limitation by the vegetative mycelium. The developmental mutants responded differently to the severe substrate limitation, which resulted in distinct profiles of growth and product formation. fwnA encodes the polyketide synthase responsible for melanin biosynthesis during aerial differentiation, and we show that conidial melanin synthesis in submerged retentostat cultures and aurasperone B production are fwnA dependent. The scl-1 and scl-2 strains are two UV mutants generated in the ?fwnA background that displayed reduced asexual conidiation and formed sclerotium-like structures on agar plates. The reduced conidiation phenotypes of the scl-1 and scl-2 strains are reflected in the retentostat cultivation and are accompanied by elimination or severely reduced accumulation of secondary metabolites and distinctly enhanced accumulation of extracellular protein. This investigation shows that submerged conidiation and product formation of a mitosporic fungus cultured at low specific growth rates can be fundamentally affected by interfering with the genetic program for differentiation of aerial hyphae, opening new perspectives for tailoring industrial performance.

J?rgensen, Thomas R.; Nielsen, Kristian F.; Arentshorst, Mark; Park, JooHae; van den Hondel, Cees A.; Frisvad, Jens C.; Ram, Arthur F.

2011-01-01

264

Submerged conidiation and product formation by Aspergillus niger at low specific growth rates are affected in aerial developmental mutants.  

PubMed

Exposure to an aerial environment or severe nutrient limitation induces asexual differentiation in filamentous fungi. Submerged cultivation of Aspergillus niger in carbon- and energy-limited retentostat cultures both induces and fuels conidiation. Physiological and transcriptomic analyses have revealed that this differentiation strongly affects product formation. Since conidiation is inherent in the aerial environment, we hypothesized that product formation near zero growth can be influenced by affecting differentiation or development of aerial hyphae in general. To investigate this idea, three developmental mutants (?fwnA, scl-1, and scl-2 mutants) that have no apparent vegetative growth defects were cultured in maltose-limited retentostat cultures. The secondary-metabolite profile of the wild-type strain defined flavasperone, aurasperone B, tensidol B, and two so far uncharacterized compounds as associated with conidium formation, while fumonisins B(2), B(4), and B(6) were characteristic of early response to nutrient limitation by the vegetative mycelium. The developmental mutants responded differently to the severe substrate limitation, which resulted in distinct profiles of growth and product formation. fwnA encodes the polyketide synthase responsible for melanin biosynthesis during aerial differentiation, and we show that conidial melanin synthesis in submerged retentostat cultures and aurasperone B production are fwnA dependent. The scl-1 and scl-2 strains are two UV mutants generated in the ?fwnA background that displayed reduced asexual conidiation and formed sclerotium-like structures on agar plates. The reduced conidiation phenotypes of the scl-1 and scl-2 strains are reflected in the retentostat cultivation and are accompanied by elimination or severely reduced accumulation of secondary metabolites and distinctly enhanced accumulation of extracellular protein. This investigation shows that submerged conidiation and product formation of a mitosporic fungus cultured at low specific growth rates can be fundamentally affected by interfering with the genetic program for differentiation of aerial hyphae, opening new perspectives for tailoring industrial performance. PMID:21652743

Jørgensen, Thomas R; Nielsen, Kristian F; Arentshorst, Mark; Park, Joohae; van den Hondel, Cees A; Frisvad, Jens C; Ram, Arthur F

2011-08-01

265

Moving beyond Frontiers: How Institutional Context Affects Degree Production and Student Aspirations in STEM  

ERIC Educational Resources Information Center

Colleges and universities in the U.S. face increasing pressure from policymakers and corporate leaders to increase their production of undergraduate degrees in science, technology, engineering, and mathematics (STEM). These pressures stem from a need to maintain the country's global economic competitiveness in science and engineering innovation.…

Eagan, Mark Kevin, Jr.

2010-01-01

266

Decreased summer drought affects plant productivity and soil carbon dynamics in a Mediterranean woodland  

Microsoft Academic Search

Precipitation patterns are expected to change in the Mediterranean region within the next decades, with projected decreases in total rainfall and increases in extreme events. We manipulated precipitation patterns in a Mediterranean woodland, dominated by Arbutus unedo L., to study the effects of changing precipitation regimes on above-ground net primary production (ANPP) and soil C dynamics, specifically plant-derived C input

M. F. Cotrufo; G. Alberti; I. Inglima; H. Marjanovic; D. Lecain; A. Zaldei; A. Peressotti; F. Miglietta

2011-01-01

267

Decreased summer drought affects plant productivity and soil carbon dynamics in Mediterranean woodland  

Microsoft Academic Search

Precipitation patterns are expected to change in the Mediterranean region within the next decades, with projected decreases in total rainfall and increases in extreme events. We manipulated precipitation patterns in a Mediterranean woodland, dominated by Arbutus unedo L., to study the effects of changing precipitation regimes on above-ground net primary production (ANPP) and soil C dynamics, specifically plant-derived C input

M. F. Cotrufo; G. Alberti; I. Inglima; H. Marjanovic; D. Lecain; A. Zaldei; A. Peressotti; F. Miglietta

2011-01-01

268

Lesion-Site Affects Grammatical Gender Assignment in German: Perception and Production Data  

ERIC Educational Resources Information Center

Two experiments investigated phonological, derivational-morphological and semantic aspects of grammatical gender assignment in a perception and a production task in German aphasic patients and age-matched controls. The agreement of a gender indicating adjective (feminine, masculine or neuter) and a noun was evaluated during perception in…

Hofmann, Juliane; Kotz, Sonja A.; Marschhauser, Anke; von Cramon, D. Yves; Friederici, Angela D.

2007-01-01

269

How technology and price affect US tight gas potential. Part 1. Technology of tight gas production  

Microsoft Academic Search

The tight gas resource in the US currently is estimated at 900 tcf, of which 600 tcf is considered technically recoverable. This gas is found in basins that cover a prospective area of one million square miles (one million sections). Of these, ca 120,000 sections are potentially productive. The tight gas picture is composed of many different and often complex

R. W. Jr. Veatch; O. Baker

1983-01-01

270

Phosphoribosyl pyrophosphate synthetase activity affects growth and riboflavin production in Ashbya gossypii  

PubMed Central

Background Phosphoribosyl pyrophosphate (PRPP) is a central compound for cellular metabolism and may be considered as a link between carbon and nitrogen metabolism. PRPP is directly involved in the de novo and salvage biosynthesis of GTP, which is the immediate precursor of riboflavin. The industrial production of this vitamin using the fungus Ashbya gossypii is an important biotechnological process that is strongly influenced by substrate availability. Results Here we describe the characterization and manipulation of two genes of A. gossypii encoding PRPP synthetase (AGR371C and AGL080C). We show that the AGR371C and AGL080C gene products participate in PRPP synthesis and exhibit inhibition by ADP. We also observed a major contribution of AGL080C to total PRPP synthetase activity, which was confirmed by an evident growth defect of the ?agl080c strain. Moreover, we report the overexpression of wild-type and mutant deregulated isoforms of Agr371cp and Agl080cp that significantly enhanced the production of riboflavin in the engineered A. gossypii strains. Conclusion It is shown that alterations in PRPP synthetase activity have pleiotropic effects on the fungal growth pattern and that an increase in PRPP synthetase enzymatic activity can be used to enhance riboflavin production in A. gossypii.

Jimenez, Alberto; Santos, Maria A; Revuelta, Jose L

2008-01-01

271

Environmental, Management, and Genetic Factors Affecting Semen Production in Holstein Bulls  

Microsoft Academic Search

The objective of this study was to evaluate the importance of environment, management, physiologi- cal status, and genetics on semen quality (volume of the ejaculate, sperm concentration, sperm motility, number of sperm, and number of motile spermatozoa per ejaculate) of Canadian Holstein bulls. For this purpose, semen production data from 198 bulls were analyzed using mixed linear models. Young bulls

M. Mathevon; M. M. Buhr; J. C. M. Dekkers

1998-01-01

272

Factors affecting successful implementation of total productive maintenance : A UK manufacturing case study perspective  

Microsoft Academic Search

Modern manufacturing requires that to be successful organisations must be supported by both effective and efficient maintenance. One approach to improving the performance of maintenance activities is to implement and develop a total productive maintenance (TPM) strategy. However, it is well documented that a number of organisations are failing to successfully implement such strategies. This paper outlines research carried out

C. J. Bamber; J. M. Sharp; M. T. Hides

1999-01-01

273

Acidification and Soil Productivity of Allophanic Andosols Affected by Heavy Application of Fertilizers  

Microsoft Academic Search

The acidification of allophanic Andosols by fertilizer application in relation to soil productivity was studied with special reference to the soil colloidal composition. Among the Japanese cultivated allophanic Andosols, in 95% of the samples, the exchange acidity y1 was < 6, while in 5% of the samples (30 soil samples) the exchange acidity y1 was ? 6. The strongly acidic

Nobuhiko Matsuyama; Masahiko Saigusa; Eiji Sakaiya; Kazunaga Tamakawa; Zenzo Oyamada; Keiichi Kudo

2005-01-01

274

HYDROLOGIC CONDITIONS AFFECTING THE TROPOSPHERIC FLUX OF VINCLOZOLIN AND ITS DEGRADATION PRODUCTS  

EPA Science Inventory

A laboratory chamber was used to determine hydrologic conditions that lead to the tropospheric flux of a suspected anti-androgenic dicarboximide fungicide, vinclozolin (3-(3,5-dichlorophenyl)-5-methyl-5-vinyl-oxzoli-dine-2,4-dione) and three degradation products from sterilized...

275

Local and systemic antibody production in horses affected with chronic obstructive pulmonary disease.  

PubMed

An enzyme-linked immunosorbent assay (ELISA) was used to quantify isotype-specific antibody to Micropolyspora faeni and to Aspergillus fumigatus in the sera and bronchoalveolar lavage fluid (BALF) of normal horses, horses with chronic obstructive pulmonary disease (COPD) and horses with other chronic respiratory diseases. Elevated antibody levels were not detected in the sera of affected horses. However, both IgE and IgA antibody to both allergens was significantly elevated in BALF in COPD affected horses sampled both when symptomatic and asymptomatic. Elevated levels were also found in animals that developed a chronic cough after an acute onset with symptoms compatible with a respiratory virus infection. In one animal a ten fold increase in IgE antibody to the two allergens developed after an interval of 7 weeks. These findings are supportive of a central role of local IgE antibody to mould allergens in the immunopathogenesis of COPD, and also suggest that respiratory viral infection may predispose to the development of COPD in some horses. PMID:8291200

Halliwell, R E; McGorum, B C; Irving, P; Dixon, P M

1993-10-01

276

A mutation in the Xanthomonas oryzae pv. oryzae wxoD gene affects xanthan production and chemotaxis.  

PubMed

Xanthomonas oryzae pv. oryzae causes bacterial blight in rice (Oryza sativa L.). The effect of a mutation in the wxoD gene, that encodes a putative O-antigen acetylase, on xanthan production as well as bacterial chemotaxis was investigated. The mutation increased xanthan production by 52 %. The mutant strain was non-motile on semi-solid agar swarm plates. In addition, several genes involved in chemotaxis, including the cheW, cheV, cheR, and cheD genes, were down-regulated by a mutation in the wxoD gene. Thus, the mutation in the wxoD gene affects xanthan production as well as bacterial chemotaxis. However, the wxoD gene is not essential for the virulence of X. oryzae. PMID:23881323

Nam, Jae-Young; Kim, Hong-Il; Lee, Chang-Soo; Park, Young-Jin

2013-11-01

277

Acute effects of static stretching on characteristics of the isokinetic angle - torque relationship, surface electromyography, and mechanomyography.  

PubMed

The aims of this study were to examine the acute effects of static stretching on peak torque, work, the joint angle at peak torque, acceleration time, isokinetic range of motion, mechanomyographic amplitude, and electromyographic amplitude of the rectus femoris during maximal concentric isokinetic leg extensions at 1.04 and 5.23 rad x s(-1) in men and women. Ten women (mean +/- s: age 23.0 +/- 2.9 years, stature 1.61 +/- 0.12 m, mass 63.3 +/- 9.9 kg) and eight men (age 21.4 +/- 3.0 years, stature 1.83 +/- 0.11 m, mass 83.1 +/- 15.2 kg) performed maximal voluntary concentric isokinetic leg extensions at 1.04 and 5.23 rad x s(-1). Following the initial isokinetic tests, the dominant leg extensors were stretched using four static stretching exercises. After the stretching, the isokinetic tests were repeated. Peak torque, acceleration time, and electromyographic amplitude decreased (P< or = 0.05) from pre- to post-stretching at 1.04 and 5.23 rad . s(-1); there were no changes (P > 0.05) in work, joint angle at peak torque, isokinetic range of motion, or mechanomyographic amplitude. These findings indicate no stretching-related changes in the area under the angle - torque curve (work), but a significant decrease in peak torque, which suggests that static stretching may cause a "flattening" of the angle - torque curve that reduces peak strength but allows for greater force production at other joint angles. These findings, in conjunction with the increased limb acceleration rates (decreased acceleration time) observed in the present study, provide tentative support for the hypothesis that static stretching alters the angle - torque relationship and/or sarcomere shortening velocity. PMID:17454536

Cramer, Joel T; Beck, Travis W; Housh, Terry J; Massey, Laurie L; Marek, Sarah M; Danglemeier, Suzanne; Purkayastha, Sushmita; Culbertson, Julie Y; Fitz, Kristi A; Egan, Alison D

2007-04-01

278

Do Interactions of Land Use and Climate Affect Productivity of Waterbirds and Prairie-Pothole Wetlands?  

Microsoft Academic Search

Availability of aquatic invertebrates on migration and breeding areas influences recruitment of ducks and shorebirds. In wetlands\\u000a of Prairie Pothole Region (PPR), aquatic invertebrate production primarily is driven by interannual fluctuations of water\\u000a levels in response to wet-dry cycles in climate. However, this understanding comes from studying basins that are minimally\\u000a impacted by agricultural landscape modifications. In the past 100–150 years,

Michael J. Anteau

279

Quantitative studies on downy mildew ( Peronospora destructor Berk. Casp.) affecting onion seed production in southern Uruguay  

Microsoft Academic Search

Onion downy mildew (Dm) symptoms and damage on seed production fields in southern Uruguay were quantified during two seasons\\u000a as the progress of incidence, severity, and as the effect of the level of seed-stalks infections on seed yield and quality.\\u000a In addition, the effects of two plantation dates and two plant densities on Dm were studied in a factorial experiment.

Pablo H. González; Paula Colnago; Sebastián Peluffo; Héctor González Idiarte; Javier Zipitría; Guillermo A. Galván

2011-01-01

280

Thermal stress and tropical cyclones affect economic production in Central America and Caribbean  

NASA Astrophysics Data System (ADS)

Surface temperatures and tropical cyclones have large impacts on economic production. Local cyclone energy dissipation reduces output in agriculture and tourism, while stimulating output in construction. High surface temperatures reduce output in several labor-intensive industries; a 1° C increase for two consecutive years results in production losses of ˜13%. The response is greatest during the hottest season and is non-linear, with high temperature days contributing the most to production losses. The structure of this response matches results from a large ergonomics literature, supporting the hypothesis that thermal stress reduces human performance, driving macroeconomic fluctuations. This large response of non-agricultural sectors suggests that current estimates underestimate the scale and scope of economic vulnerabilities to climate change. Responses of each industry to surface temperature, tropical cyclones and rainfall. Estimates represent the change of value-added in the industry in response to each atmospheric variables during the year of production (L=0) and the years prior (L?1). The responses to surface temperature are triangles, tropical cyclones are squares and rainfall are crosses. Estimates are grey if none of the annual responses are significant at the ? = 0.1 level. Whiskers indicate 95% confidence intervals. Tourism receipts displays the five years prior (L=1-5) because of the long response of that industry to cyclones. Agriculture per worker is also plotted as circles when estimated a second time excluding mainland countries from the sample. Units are: temperature- percent change in output per 0.33°C; cyclones- percent changes in output per 1 standard deviation of tropical cyclone energy; rainfall- percent change in output per 2 cm/month.

Hsiang, S. M.

2009-12-01

281

Biomass production and nutrient removal by Chlorella sp. as affected by sludge liquor concentration.  

PubMed

The use of microalgae for biomass production and nutrient removal from the reject water produced in the dewatering process of anaerobically digested sludge, sludge liquor, was investigated. The sludge liquor was characterized by a high content of total suspended solids (1590 mg L(-1)), a high nitrogen concentration (1210 mg L(-1)), and a low phosphorus concentration (28 mg L(-1)). Chlorella sp. was grown in sludge liquor diluted with wastewater treatment plant effluent water to different concentrations (12, 25, 40, 50, 70, and 100%) using batch mode. The environmental conditions were 25 °C, a continuous lightning of 115 ?mol m(-2) s(-1), and a CO2 concentration of 3.0%. The highest biomass production (0.42-0.45 g dry weight L(-1) Day(-1)) was achieved at 40-50% sludge liquor, which was comparable to the production of the control culture grown with an artificial fertilizer. The biomass production was 0.12 and 0.26 g dry weight L(-1) Day(-1) at 12% and 100% sludge liquor, respectively. The percentage of nitrogen in the algal biomass increased from 3.6% in 12% sludge liquor and reached a saturation of ?10% in concentrations with 50% sludge liquor and higher. The phosphorus content in the biomass increased linearly from 0.2 to 1.5% with increasing sludge liquor concentrations. The highest nitrogen removal rates by algal biosynthesis were 33.6-42.6 mg TN L(-1) Day(-1) at 40-70% sludge liquor, while the highest phosphorus removal rates were 3.1-4.1 mg TP L(-1) Day(-1) at 50-100% sludge liquor. PMID:24935023

Akerström, Anette M; Mortensen, Leiv M; Rusten, Bjørn; Gislerød, Hans Ragnar

2014-11-01

282

Tetrazolium-based Assays for Cellular Viability: A Critical Examination of Selected Parameters Affecting Formazan Production  

Microsoft Academic Search

The hydrogen acceptor 3-(4,5-dimethylthiazol-2-yl)-2,5 diphenyItetra- zolium bromide (Mil) is commonlyutilized to estimate cellular viability in drug screening protocols. The present investigation was prompted, in part, by observations that reduction of MTT to its colored reaction product, MTT formazan, varied between cell lines and with culture age. A correlation was established between the D-glucoseconcentration of the culture mediumat the time of

David T. Vistica; Philip Skehan; Dominic Scudiero; Anne Monks; Angela Pittman; Michael R. Boyd

1991-01-01

283

Shiga toxin-1 affects nitric oxide production by human glomerular endothelial and mesangial cells  

Microsoft Academic Search

Acute renal failure hallmarks the pathogenesis of the epidemic form of hemolytic uremic syndrome (D+HUS), which is caused by E. coli strains that produce Shiga-like toxin (Stx). In this study, we investigated the influence of Stx-1 on nitric oxide (NO) production by human glomerular microvascular endothelial cells (GMVEC) and human mesangial cells. NO synthesis by human mesangial cells is in

D. Maroeska te Loo; L. A. H. Monnens; T. J. A. M. van der Velden; Mohammed Karmali; Lambertus van den Heuvel; Victor van Hinsbergh

2006-01-01

284

Management regimes affect woody plant productivity and water use efficiency in an urban desert ecosystem  

Microsoft Academic Search

Woody plant productivity and water use were evaluated under various management regimes in the Central Arizona Phoenix Long\\u000a Term Ecological Research study area during 1999–2003. Management was defined as alteration of plant density, irrigation of\\u000a plants, and removal of plant biomass via pruning. In a ground survey of 204 randomly chosen sites woody plant canopy area\\u000a (CA) was higher in

L. Brooke Stabler

2008-01-01

285

Bevel Gear Driver and Method Having Torque Limit Selection  

NASA Technical Reports Server (NTRS)

Methods and apparatus are provided for a torque driver including an axially displaceable gear with a biasing assembly to bias the displaceable gear into an engagement position. A rotatable cap is provided with a micrometer dial to select a desired output torque. An intermediate bevel gear assembly is disposed between an input gear and an output gear. A gear tooth profile provides a separation force that overcomes the bias to limit torque at a desired torque limit. The torque limit is adjustable and may be adjusted manually or automatically depending on the type of biasing assembly provided. A clutch assembly automatically limits axial force applied to a fastener by the operator to avoid alteration of the desired torque limit.

Cook, Joseph S., Jr. (Inventor)

1997-01-01

286

Factors affecting Anastrepha fraterculus female receptivity modulation by accessory gland products.  

PubMed

In the context of the sterile insect technique (SIT), mass-rearing and male irradiation are imperative. Post-teneral treatments such as the addition of protein in adult's male diet and male hormonal treatment are used to improve sexual performance and to accelerate sexual maturation. In this work we investigated the effect of male accessory glands products (AGPs) on female receptivity of the South American fruit fly Anastrepha fraterculus (Wiedemann), and the effect of strain rearing history, male irradiation, male diet and hormonal treatment on AGPs. Injections of aqueous extracts of male accessory glands into the abdomen of females reduced their receptivity. The AGPs from laboratory males were more effective in inhibiting female receptivity, compared to AGPs from wild males, irrespective of females' origin. The AGPs from fertile males were more effective than AGPs from sterile males. The AGPs from protein-fed males were more effective than AGPs from sugar-fed males. Finally, the AGPs of males treated with juvenile hormone were less effective in inhibiting female receptivity than AGPs of untreated males. We conclude that inhibition of sexual receptivity of A. fraterculus mated females is mediated by products in male accessory gland's and the way that these products act vary widely according to the effect of extrinsic factors. We discuss the results in the perspective of the SIT application for A. fraterculus. PMID:21907717

Abraham, Solana; Cladera, Jorge; Goane, Lucía; Teresa Vera, M

2012-01-01

287

Shiga toxin-1 affects nitric oxide production by human glomerular endothelial and mesangial cells.  

PubMed

Acute renal failure hallmarks the pathogenesis of the epidemic form of hemolytic uremic syndrome (D+HUS), which is caused by E. coli strains that produce Shiga-like toxin (Stx). In this study, we investigated the influence of Stx-1 on nitric oxide (NO) production by human glomerular microvascular endothelial cells (GMVEC) and human mesangial cells. NO synthesis by human mesangial cells is in the micromolar range and that of GMVEC in the picomolar range. Stx-1 reduced NO production in non-stimulated GMVEC (5 nmol/l Stx-1 required) without inhibition of protein synthesis. In non-stimulated and TNFalpha-pretreated mesangial cells, NO production was reduced with a maximal reduction at 10 fmol/l shiga toxin. The cellular iNOS antigen content in mesangial cells was reduced in a concentration-dependent way (10 fmol/l-100 pmol/l), while partial inhibition of protein synthesis required 10 nmol/l Stx-1 in these cells. Our in vitro data suggest that Stx may reduce NO synthesis during the course of HUS development, contributing to the aggravation of the thrombotic microangiopathy and renal failure as observed in HUS. PMID:16944213

Te Loo, D Maroeska; Monnens, Leo; van der Velden, Thea; Karmali, Mohammed; van den Heuvel, Lambertus; van Hinsbergh, Victor

2006-12-01

288

Environmental conditions affecting exopolysaccharide production by Pseudomonas aeruginosa, Micrococcus sp., and Ochrobactrum sp.  

PubMed

Three different chromium-resistant microorganisms (Pseudomonas aeruginosa, Micrococcus sp., and Ochrobactrum sp.) were tested with regard to their EPS production at different pH levels, temperatures, Cr(VI) concentrations, and incubation periods. The optimum pH level was 7 for P. aeruginosa and Micrococcus sp., while it was 8 for Ochrobactrum sp. according to the highest EPS amount at 100 mg/L Cr(VI) concentration. The highest production of EPSs by the three bacteria was obtained under different environmental conditions. P. aeruginosa produced the highest EPS (863.3 mg/L) after incubation for 96 h on media with 50 mg/L Cr(VI) at 20 degrees C, Micrococcus sp. gave the highest yield (444.6 mg/L) after incubation for 72 h on media with 100 mg/L Cr(VI) at the same temperature, and Ochrobactrum sp. had the highest production (430.5 mg/L) on media with 150 mg/L Cr(VI) at 30 degrees C at the end of 48 h of incubation. PMID:18155834

Kiliç, Nur Koçberber; Dönmez, Gönül

2008-06-15

289

Variables that affect xylitol production from sugarcane bagasse hydrolysate in a zeolite fluidized bed reactor.  

PubMed

The operational conditions for xylitol production by fermentation of sugarcane bagasse hydrolysate in a fluidized bed reactor with cells immobilized on zeolite were evaluated. Fermentations were carried out under different conditions of air flowrate (0.0125-0.0375 vvm), zeolite mass (100-200 g), initial pH (4-6), and xylose concentration (40-60 g/L), according to a 2(4) full factorial design. The air flowrate increase resulted in a metabolic deviation from product to biomass formation. On the other hand, the pH increase favored both the xylitol yield (Y(P/S)) and volumetric productivity (Q(P)), and the xylose concentration increase positively influenced the xylitol concentration. The best operational conditions evaluated were based on the use of an air flowrate of 0.0125 vvm, 100 g of zeolite, pH 6, and xylose concentration of 60 g/L. Under these conditions, 38.5 g/L of xylitol were obtained, with a Y(P/S) of 0.72 g/g, Q(P) of 0.32 g/L.h, and cell retention of 25.9%. PMID:16321046

Santos, Júlio C; Mussatto, Solange I; Cunha, Mário A A; Silva, Silvio S

2005-01-01

290

Mutations Affecting Hyphal Colonization and Pyoverdine Production in Pseudomonads Antagonistic toward Phytophthora parasitica  

PubMed Central

In previous studies, Pseudomonas putida 06909 and Pseudomonas fluorescens 09906 suppressed populations of Phytophthora parasitica in the citrus rhizosphere, suggesting that these bacteria may be useful in biological control of citrus root rot. In this study we investigated the mechanisms of antagonism between the bacteria and the fungus. Both bacteria colonized Phytophthora hyphae and inhibited the fungus on agar media. A hyphal column assay was developed to measure the colonization of bacteria on fungal hyphae and to enrich for colonization-deficient mutants. In this way we identified Tn5 mutants of each pseudomonad that were not able to colonize the hyphae and inhibit fungal growth in vitro. Colonization-deficient mutants were nonmotile and lacked flagella. Survival of nonmotile mutants in a citrus soil was similar to survival of a random Tn5 mutant over a 52-day period. Additional screening of random Tn5 mutants of both pseudomonads for loss of fungal inhibition in vitro yielded two distinct types of mutants. Mutants of the first type were deficient in production of pyoverdines and in inhibition of the fungus in vitro, although they still colonized fungal hyphae. Mutants of the second type lacked flagella and were not able to colonize the hyphae or inhibit fungal growth. No role was found for antibiotic production by the two bacteria in the inhibition of the fungus. Our results suggest that both hyphal colonization and pyoverdine production are important in the inhibition of Phytophthora parasitica by P. fluorescens and P. putida in vitro. Images

Yang, Ching-Hong; Menge, John A.; Cooksey, Donald A.

1994-01-01

291

Carnosine inhibits KRAS-mediated HCT116 proliferation by affecting ATP and ROS production.  

PubMed

Carnosine is a natural dipeptide that has generated particular interest for its antioxidant, anti-aging and especially for its antiproliferative properties. In this study, we demonstrate that carnosine inhibits the proliferation of human HCT116 colon cancer cells. In this cell line, the activating KRAS mutation induces mitochondrial ROS, the signaling molecules for cell proliferation. We observed that 50-100 mM carnosine decreases ATP and ROS concentration and induces cell cycle arrest in G1 phase. In HCT116 cells these effects are related to decreased ERK1/2 phosphorylation and increased p21waf1 protein. Our findings support the concept that carnosine could inhibit HCT116 cell growth via its antioxidant activity and its ability to affect glycolysis. PMID:22137144

Iovine, Barbara; Iannella, Maria Luigia; Nocella, Francesca; Pricolo, Maria Rosaria; Bevilacqua, Maria Assunta

2012-02-28

292

Oxygen concentration affects volatile compound biosynthesis during virgin olive oil production.  

PubMed

The effect of O 2 concentration on oil volatile compounds synthesized during the process to obtain virgin olive oil (VOO) was established. The study was carried out either on the whole process or within the main steps (milling and malaxation) of this process with two olive cultivars, Picual and Arbequina, at two ripening stages. Data show that O 2 control during milling has a negative impact on VOO volatile synthesis. This effect seems to depend on cultivar and on the ripening stage in cultivar Picual. Because most VOO volatiles are synthesized during olive fruit crushing at the milling step, O 2 control during malaxation seems to affect just slightly the volatile synthesis. The highest effect was observed when control of O 2 concentration was performed over the whole process. In this case, the content of volatile compounds of oils obtained from both cultivars and ripening stages showed quite similar trends. PMID:18510335

Sánchez-Ortiz, Araceli; Romero, Carmen; Pérez, Ana G; Sanz, Carlos

2008-06-25

293

Four Phase Switched Reluctance Motor Direct Torque Control  

Microsoft Academic Search

The three-phase switched reluctance motor direct torque control method mostly is a simple transplantation of the three-phase AC asynchronous motor direct torque control method, not suitable for arbitrary-phase switched reluctance motor. In this paper, the direct torque control method for the application of a wide range of four-phase switched reluctance motor will be researched, the structural methods of a four-

Wang Mianhua

2011-01-01

294

Thermomechanical characterization of shape memory alloy torque tube actuators  

Microsoft Academic Search

A parametric study was performed on NiTiCu shape memory alloy torque tubes. Four samples with varying wall thickness values were evaluated for their thermo-mechanical response. The torque against the angular displacement was measured for each sample when purely martensitic and purely austenitic. The recovery torque was measured as a function of the pretwist applied during loading in the martensite phase.

Andrew C. Keefe; Gregory P. Carman

2000-01-01

295

Electronic measurement of variable torques in precision work technology  

NASA Technical Reports Server (NTRS)

Approaches for the determination of torques on the basis of length measurements are discussed. Attention is given to torque determinations in which the deformation of a shaft is measured, an electric measurement of the torsion angle, and an approach proposed by Buschmann (1970). Methods for a torque determination conducted with the aid of force measurements make use of piezoelectric approaches. The components used by these methods include a quartz crystal and a charge amplifier.

Maehr, M.

1978-01-01

296

Thickness dependence of spin torque ferromagnetic resonance in Co75Fe25/Pt bilayer films  

NASA Astrophysics Data System (ADS)

The spin Hall angle of Pt in Co75Fe25/Pt bilayer films was experimentally investigated by means of the spin-torque ferromagnetic resonance and the modulation of damping measurements. By comparing the present results with the Ni80Fe20/Pt system, we found that the ferromagnetic layer underneath the Pt one greatly affects the estimation of the spin Hall angle. We also discuss the spin diffusion length of Pt and the ferromagnetic thickness dependence of the Gilbert damping coefficient.

Ganguly, A.; Kondou, K.; Sukegawa, H.; Mitani, S.; Kasai, S.; Niimi, Y.; Otani, Y.; Barman, A.

2014-02-01

297

Transfer from long to short photoperiods affects production efficiency of day-neutral rice  

NASA Technical Reports Server (NTRS)

The day-neutral, semidwarf rice (Oryza sativa L.) cultivar Ai-Nan-Tsao was grown in a greenhouse under summer conditions using high-pressure sodium lamps to extend the natural photoperiod. After allowing 2 weeks for germination, stand establishment, and thinning to a consistent planting density of 212 plants/m2, stands were maintained under continuous lighting for 35 or 49 days before shifting to 8- or 12-h photoperiods until harvest 76 days after planting. Non-shifted control treatments consisting of 8-, 12-, or 24-h photoperiods also were maintained throughout production. Tiller number increased as duration of exposure to continuous light increased before shifting to shorter photoperiods. However, shoot harvest index and yield efficiency rate were lower for all plants receiving continuous light than for those under the 8- or 12-h photoperiods. Stands receiving 12-h photoperiods throughout production had the highest grain yield per plant and equaled the 8-h-photoperiod control plants for the lowest tiller number per plant. As long as stands were exposed to continuous light, tiller formation continued. Shifting to shorter photoperiods late in the cropping cycle resulted in newly formed tillers that were either sterile or unable to mature grain before harvest. Late-forming tillers also suppressed yield of grain in early-forming tillers, presumably by competing for photosynthate or for remobilized assimilate during senescence. Stands receiving 12-h photoperiods throughout production not only produced the highest grain yield at harvest but had the highest shoot harvest index, which is important for resource-recovery strategies in advanced life-support systems proposed for space.

Goldman, K. R.; Mitchell, C. A.

1999-01-01

298

Medium-chain fatty acids affect citrinin production in the filamentous fungus Monascus ruber.  

PubMed

During submerged culture in the presence of glucose and glutamate, the filamentous fungus Monascus ruber produces water-soluble red pigments together with citrinin, a mycotoxin with nephrotoxic and hepatoxic effects on animals. Analysis of the (13)C-pigment molecules from mycelia cultivated with [1-(13)C]-, [2-(13)C]-, or [1, 2-(13)C]acetate by (13)C nuclear magnetic resonance indicated that the biosynthesis of the red pigments used both the polyketide pathway, to generate the chromophore structure, and the fatty acid synthesis pathway, to produce a medium-chain fatty acid (octanoic acid) which was then bound to the chromophore by a trans-esterification reaction. Hence, to enhance pigment production, we tried to short-circuit the de novo synthesis of medium-chain fatty acids by adding them to the culture broth. Of fatty acids with carbon chains ranging from 6 to 18 carbon atoms, only octanoic acid showed a 30 to 50% stimulation of red pigment production, by a mechanism which, in contrast to expectation, did not involve its direct trans-esterification on the chromophore backbone. However, the medium- and long-chain fatty acids tested were readily assimilated by the fungus, and in the case of fatty acids ranging from 8 to 12 carbon atoms, 30 to 40% of their initial amount transiently accumulated in the growth medium in the form of the corresponding methylketone 1 carbon unit shorter. Very interestingly, these fatty acids or their corresponding methylketones caused a strong reduction in, or even a complete inhibition of, citrinin production by M. ruber when they were added to the medium. Several data indicated that this effect could be due to the degradation of the newly synthesized citrinin (or an intermediate in the citrinin pathway) by hydrogen peroxide resulting from peroxisome proliferation induced by medium-chain fatty acids or methylketones. PMID:10698780

Hajjaj, H; Klaébé, A; Goma, G; Blanc, P J; Barbier, E; François, J

2000-03-01

299

Do new cellulolytic enzyme preparations affect the industrial strategies for high solids lignocellulosic ethanol production?  

PubMed

Production of ethanol from lignocellulosic materials has a promising market potential, but the process is still only at pilot/demonstration scale due to the technical and economical difficulties of the process. Operating the process at very high solids concentrations (above 20% dry matter-DM) has proven essential for economic feasibility at industrial scale. Historically, simultaneous saccharification and fermentation (SSF) was found to give better ethanol yields compared to separate hydrolysis and fermentation (SHF), but data in literature are typically based on operating the process at low dry matter conditions. In this work the impact of selected enzyme preparation and processing strategy (SHF, presaccharification and simultaneous saccharification and fermentation-PSSF, and SSF) on final ethanol yield and overall performance was investigated with pretreated wheat straw up to 30% DM. The experiments revealed that an SSF strategy was indeed better than SHF when applying an older generation enzyme cocktail (Celluclast-Novozym 188). In case of the newer product Cellic CTec 2, SHF resulted in 20% higher final ethanol yield compared to SSF. It was possible to close the mass balance around cellulose to around 94%, revealing that the most relevant products could be accounted for. One observation was the presence of oxidized sugar (gluconic acid) upon enzymatic hydrolysis with the latest enzyme preparation. Experiments showed gluconic acid formation by recently discovered enzymatic class of lytic polysaccharides monoxygenases (LPMO's) to be depending on the processing strategy. The lowest concentration was achieved in SSF, which could be correlated with less available oxygen due to simultaneous oxygen consumption by the yeast. Quantity of glycerol and cell mass was also depending on the selected processing strategy. PMID:24022674

Cannella, David; Jørgensen, Henning

2014-01-01

300

Spin torque-generated magnetic droplet solitons.  

PubMed

Dissipative solitons have been reported in a wide range of nonlinear systems, but the observation of their magnetic analog has been experimentally challenging. Using spin transfer torque underneath a nanocontact on a magnetic thin film with perpendicular magnetic anisotropy (PMA), we have observed the generation of dissipative magnetic droplet solitons and report on their rich dynamical properties. Micromagnetic simulations identify a wide range of automodulation frequencies, including droplet oscillatory motion, droplet "spinning," and droplet "breather" states. The droplet can be controlled by using both current and magnetic fields and is expected to have applications in spintronics, magnonics, and PMA-based domain-wall devices. PMID:23493707

Mohseni, S M; Sani, S R; Persson, J; Nguyen, T N Anh; Chung, S; Pogoryelov, Ye; Muduli, P K; Iacocca, E; Eklund, A; Dumas, R K; Bonetti, S; Deac, A; Hoefer, M A; Akerman, J

2013-03-15

301

Small-Bolt Torque-Tension Tester  

NASA Technical Reports Server (NTRS)

The device described here measures the torque-tension relationship for fasteners as small as #0. The small-bolt tester consists of a plate of high-strength steel into which three miniature load cells are recessed. The depth of the recess is sized so that the three load cells can be shimmed, the optimum height depending upon the test hardware. The three miniature load cells are arranged in an equilateral triangular configuration with the test bolt aligned with the centroid of the three. This is a kinematic arrangement.

Posey, Alan J.

2009-01-01

302

Methodology for Determining Limit Torques for Threaded Fasteners  

NASA Technical Reports Server (NTRS)

In aerospace design, where minimizing weight is always a priority, achieving the full capacity from fasteners is essential. To do so, the initial bolt preload must be maximized. The benefits of high preload are well documented and include improved fatigue resistance, a stiffer joint, and resistance to loosening. But many factors like elastic interactions and embedment tend to lower the initial preload placed on the bolt. These factors provide additional motivation to maximize the initial preload. But, to maximize bolt preload, you must determine what torque to apply. Determining this torque is greatly complicated by the large preload scatter generally seen with torque control. This paper presents a detailed methodology for generating limit torques for threaded fasteners. This methodology accounts for the large scatter in preload found with torque control, and therefore, addresses the statistical nature of the problem. It also addresses prevailing torque, a feature common in aerospace fasteners. Although prevailing torque provides a desired locking feature, it can also increase preload scatter. In addition, it can limit the amount of preload that can be generated due to the torsion it creates in the bolt. This paper discusses the complications of prevailing torque and how best to handle it. A wide range of torque-tension bolt testing was conducted in support of this research. The results from this research will benefit the design engineer as well as analyst involved in the design of bolted joints, leading to better, more optimized structural designs.

Hissam, Andy

2011-01-01

303

Note: nonlinear susceptibility from high DC field torque magnetometry.  

PubMed

Torque magnetometry is a convenient technique to measure the magnetic properties of anisotropic materials. Advances in micromachining have made torque magnetometers precise and reliable even in adverse conditions such as very high magnetic fields and very low temperatures. In most applications with such magnetometers the measured torque signals are used to arrive at the linear magnetic susceptibility. In this short note we extend torque magnetometry to measure nonlinear susceptibilities and illustrate our methods with representative data on the heavy fermion compound UPt3. PMID:24784685

Shivaram, B S

2014-04-01

304

Reproducibility of isokinetic peak torque and angle at peak torque in the shoulder joint.  

PubMed

Adequate reliability studies of knee flexion and extension are currently available for isokinetic measurements, but not for the shoulder joint. For this reason, this study examines the variability (%) in the determination of peak torque (PT) and the angle at peak torque (AP) in the test-retest procedure. Differentiation is made between the various types of work (concentric, isometric, eccentric) and the degrees of freedom in the shoulder joint (flexion/extension, abduction/adduction, external rotation/internal rotation). The results show a variability of PT for concentric measurements of 15.0%-19.0% for all degrees of freedom; for flexion/extension and abduction/adduction in isometric and eccentric work, the variability is 17.5%-25.3%. External and internal rotation show generally greater deviation (29.0%-35.3%), except in concentric work. The angle at peak torque can only be reproduced to a limited degree (25.1%-41.1% variability). It is concluded that lower reproducibility can be attained for the shoulder joint compared to the knee joint, depending on the degree of freedom and exercise form tested. It appears meaningful to cite only ranges for the angle at peak torque. PMID:8157380

Mayer, F; Horstmann, T; Kranenberg, U; Röcker, K; Dickhuth, H H

1994-01-01

305

Do interactions of land use and climate affect productivity of waterbirds and prairie-pothole wetlands?  

USGS Publications Warehouse

Availability of aquatic invertebrates on migration and breeding areas influences recruitment of ducks and shorebirds. In wetlands of Prairie Pothole Region (PPR), aquatic invertebrate production primarily is driven by interannual fluctuations of water levels in response to wet-dry cycles in climate. However, this understanding comes from studying basins that are minimally impacted by agricultural landscape modifications. In the past 100–150 years, a large proportion of wetlands within the PPR have been altered; often water was drained from smaller to larger wetlands at lower elevations creating consolidated, interconnected basins. Here I present a case study and I hypothesize that large basins receiving inflow from consolidation drainage have reduced water-level fluctuations in response to climate cycles than those in undrained landscapes, resulting in relatively stable wetlands that have lower densities of invertebrate forage for ducks and shorebirds and also less foraging habitat, especially for shorebirds. Furthermore, stable water-levels and interconnected basins may favor introduced or invasive species (e.g., cattail [Typha spp.] or fish) because native communities "evolved" in a dynamic and isolated system. Accordingly, understanding interactions between water-level fluctuations and landscape modifications is a prerequisite step to modeling effects of climate change on wetland hydrology and productivity and concomitant recruitment of waterbirds.

Anteau, Michael J.

2012-01-01

306

Extracellular pH affects inflammatory cell production of superoxide and nitric oxide.  

PubMed

Previous research has described how high cellular metabolism creates an acidic environment in inflammatory cells during respiratory burst. The aim of our work was to describe the acid-base dependence of exudate in superoxide (O2.-) and nitric oxide (NO.) generation by inflammatory cells from a carrageenan-granuloma. Although the carrageenan solution was alkaline (pH 7.74 when equilibrated with air) the exudate showed an acidification that stabilised at around 7 units of pH. A notable hypercapnia, but not hypoxia, was found in the exudate at up to 24 h. The effect of extracellular acidosis on O2.- and NO. production by inflammatory cells was also studied. The maximum O2.- production and the lowest levels of NO. were found at pH 7, which was closer to the pH of the granuloma-pouch. These results suggest that experiments with inflammatory cells ex vivo should be carried out at an identical pH to that found in vivo in order to reproduce the physiological mechanisms of free radical generation during inflammatory processes. PMID:12435087

Carbonell, T; Ródenas, J; Alfaro, V; Mitjavila, M T; Palacios, L

2002-06-01

307

Interspecific differences in egg production affect egg trace element concentrations after a coal fly ash spill.  

PubMed

In oviparous vertebrates, trace elements transfer from mother to offspring during egg production. For animals that produce eggs slowly, like turtles, the trace element concentration of each egg reflects an integration of dietary and stored accumulation over the duration of vitellogenesis. Because turtles also produce eggs synchronously, all eggs within a clutch should exhibit uniform trace element concentrations. In contrast, for animals that produce eggs in sequence and primarily from current dietary resources, like many birds, the trace element concentrations of eggs should be less uniform within a clutch, and likely reflect short-term changes in dietary exposure. We tested the hypothesis that stinkpot turtle (Sternotherus odoratus) clutches exhibit lower variability and higher repeatability in barium, selenium, strontium, and thallium concentrations than those of tree swallows (Tachycineta bicolor) from a site impacted by a recent coal ash spill. All four trace elements exhibited significantly lower variability and significantly higher repeatability in stinkpot clutches than in swallow clutches. Mean trace element concentrations of stinkpot eggs were also significantly higher than those of swallow eggs although both species feed primarily on aquatic invertebrates. Variability in swallow egg trace element concentrations was partially due to significant laying order effects. Our results support the hypothesis that interspecific variation in the source of resources and in the synchronicity and rate of egg production can lead to interspecific differences in the variability of egg trace element concentrations. PMID:24180645

Van Dyke, James U; Beck, Michelle L; Jackson, Brian P; Hopkins, William A

2013-12-01

308

EDITORIAL: Spin-transfer-torque-induced phenomena Spin-transfer-torque-induced phenomena  

NASA Astrophysics Data System (ADS)

This cluster, consisting of five invited articles on spin-transfer torque, offers the very first review covering both magnetization reversal and domain-wall displacement induced by a spin-polarized current. Since the first theoretical proposal on spin-transfer torque—reported by Berger and Slonczewski independently—spin-transfer torque has been experimentally demonstrated in both vertical magnetoresistive nano-pillars and lateral ferromagnetic nano-wires. In the former structures, an electrical current flowing vertically in the nano-pillar exerts spin torque onto the thinner ferromagnetic layer and reverses its magnetization, i.e., current-induced magnetization switching. In the latter structures, an electrical current flowing laterally in the nano-wire exerts torque onto a domain wall and moves its position by rotating local magnetic moments within the wall, i.e., domain wall displacement. Even though both phenomena are induced by spin-transfer torque, each phenomenon has been investigated separately. In order to understand the physical meaning of spin torque in a broader context, this cluster overviews both cases from theoretical modellings to experimental demonstrations. The earlier articles in this cluster focus on current-induced magnetization switching. The magnetization dynamics during the reversal has been calculated by Kim et al using the conventional Landau--Lifshitz-Gilbert (LLG) equation, adding a spin-torque term. This model can explain the dynamics in both spin-valves and magnetic tunnel junctions in a nano-pillar form. This phenomenon has been experimentally measured in these junctions consisting of conventional ferromagnets. In the following experimental part, the nano-pillar junctions with perpendicularly magnetized FePt and half-metallic Heusler alloys are discussed from the viewpoint of efficient magnetization reversal due to a high degree of spin polarization of the current induced by the intrinsic nature of these alloys. Such switching can be further operated at high frequency resulting in an oscillator, as shown in the article by Sulka et al. These results provide fundamental elements for magnetic random access memories. The later articles discuss domain-wall displacement. Again this phenomenon is also described by Shibata et al based on the LLG equation with spin-torque terms. This analytical model can explain the details of the depinning mechanism and a critical current for the displacement. Experimental observation is presented in the subsequent article by Malinowski et al, showing the depinning processes for the cases of intrinsic and extrinsic pinning sites. Here, the detailed magnetic moment configurations within the wall hold the dominant control over the critical current. These results can be used for future 3-dimensional magnetic memories, such as racetrack memory proposed by IBM. We sincerely hope this cluster offers an up-to-date understanding of macroscopic behaviour induced by spin-transfer torque and contributes to further advancement in this exciting research field. We are grateful to all the authors for spending their precious time and knowledge submitting to this cluster. We would also like to thank Professor Kevin O'Grady for his kind offer of the opportunity to make this review accessible to a general audience.

Hirohata, Atsufumi

2011-09-01

309

Galactoglucomannan oligosaccharide supplementation affects nutrient digestibility, fermentation end-product production, and large bowel microbiota of the dog.  

PubMed

A galactoglucomannan oligosaccharide (GGMO) obtained from fiberboard production was evaluated as a dietary supplement for dogs. The GGMO substrate contained increased concentrations of oligosaccharides containing mannose, xylose, and glucose, with the mannose component accounting for 35% of DM. Adult dogs assigned to a 6 × 6 Latin square design were fed 6 diets, each containing a different concentration of supplemental GGMO (0, 0.5, 1, 2, 4, and 8%) that replaced dietary cellulose. Total tract DM and OM apparent digestibilities increased (P < 0.001) linearly, whereas total tract CP apparent digestibility decreased (P < 0.001) linearly as dietary GGMO substrate concentration increased. Fecal concentrations of acetate, propionate, and total short-chain fatty acids increased (P ? 0.001) linearly, whereas butyrate concentration decreased (P ? 0.001) linearly with increasing dietary concentrations of GGMO. Fecal pH decreased (P ? 0.001) linearly as dietary GGMO substrate concentration increased, whereas fecal score increased quadratically (P ? 0.001). Fecal phenol (P ? 0.05) and indole (P ? 0.01) concentrations decreased linearly with GGMO supplementation. Fecal biogenic amine concentrations were not different among treatments except for phenylethylamine, which decreased (P < 0.001) linearly as dietary GGMO substrate concentration increased. Fecal microbial concentrations of Escherichia coli, Lactobacillus spp., and Clostridium perfringens were not different among treatments. A quadratic increase (P ? 0.01) was noted for Bifidobacterium spp. as dietary GGMO substrate concentration increased. The data suggest positive nutritional properties of supplemental GGMO when incorporated in a good-quality dog food. PMID:20852078

Faber, T A; Hopkins, A C; Middelbos, I S; Price, N P; Fahey, G C

2011-01-01

310

Enterococcus faecium isolated from Lombo, a Portuguese traditional meat product: characterisation of antibacterial compounds and factors affecting bacteriocin production.  

PubMed

Strain ST211CH, identified as a strain of Enterococcus faecium, isolated from Lombo produced a bacteriocin that inhibited the growth of Enterococcus spp., Listeria spp., Klebsiella spp., Lactobacillus spp., Pseudomonas spp., Staphylococcus spp. and Streptococcus spp. The mode of action of the bacteriocin named as bacteriocin ST211Ch was bactericidal against Enterococcus faecalis ATCC19443. As determined by Tricine-SDS-PAGE, the approximate molecular mass of the bacteriocin was 8.0 kDa. Loss in antimicrobial activity was recorded after treatment with proteolytic enzymes. Maximum activity of bacteriocin ST211Ch was measured in broth cultures of E. faecium strain ST211Ch after 24 h; thereafter, the activity was reduced. Bacteriocin ST211Ch remained active after exposure to various temperatures and pHs, as well as to Triton X-100, Tween-80, Tween-20, sodium dodecyl sulfate, NaCl, urea and EDTA. Effect of media components on production of bacteriocin ST211Ch was also studied. On the basis of PCR reactions targeting different bacteriocin genes, i.e. enterocins, curvacins and sakacins, no evidences for the presence of these genes in the total DNA of E. faecium strain ST211Ch was obtained. The bacterium most probably produced a bacteriocin different from those mentioned above. Based on the antimicrobial spectrum, stability and mode of action of bacteriocin ST211CH, E. faecium strain ST211Ch might be considered as a potential candidate with beneficial properties for use in biopreservation to control food spoilage bacteria. PMID:23234731

Todorov, S D; Favaro, L; Gibbs, P; Vaz-Velho, M

2012-12-01

311

A Novel DTC Strategy of Torque and Flux Control for Switched Reluctance Motor Drive  

Microsoft Academic Search

In this paper, a novel methodology for control of torque and flux of switched reluctance motor (SRM) drive in a hystersis manner is described. The philosophy of control is the direct torque control (DTC) by analysis the non-uniform torque characteristics of the motor. The scheme directly controls the torque and the torque ripple by controlling the magnitude of flux linkage

R. Jeyabharath; P. Veena; M. Rajaram

2006-01-01

312

An efficient torque control algorithm for BLDCM with a general shape of back EMF  

Microsoft Academic Search

The authors completely characterize the whole class of the torque control algorithms that enable the brushless DC motors to behave like linear systems but with no torque ripple. The previously known torque control algorithms correspond to either the particular ones in the whole class of the torque control algorithms or their truncated Fourier expansions. The whole class of these torque

Chang-Ik Kang; In-Joong Ha

1993-01-01

313

Small doses, big troubles: modeling growth dynamics of organisms affecting microalgal production cultures in closed photobioreactors.  

PubMed

The destruction of mass cultures of microalgae by biological contamination of culture medium is a pervasive and expensive problem, in industry and research. A mathematical model has been formulated that attempts to explain contaminant growth dynamics in closed photobioreactors (PBRs). The model simulates an initial growth phase without PBR dilution, followed by a production phase in which culture is intermittently removed. Contaminants can be introduced at any of these stages. The model shows how exponential growth from low initial inocula can lead to "explosive" growth in the population of contaminants, appearing days to weeks after inoculation. Principal influences are contaminant growth rate, PBR dilution rate, and the size of initial contaminant inoculum. Predictions corresponded closely with observed behavior of two contaminants, Uronema sp. and Neoparamoeba sp., found in operating PBRs. A simple, cheap and effective protocol was developed for short-term prediction of contamination in PBRs, using microscopy and archived samples. PMID:23262008

Forehead, Hugh I; O'Kelly, Charles J

2013-02-01

314

Ace2p, a regulator of CTS1 (chitinase) expression, affects pseudohyphal production in Saccharomyces cerevisiae.  

PubMed

Some diploid strains of Saccharomyces cerevisiae can grow both as a spherical yeast form and as a filamentous pseudohyphal form. Most yeasts capable of forming pseudohyphae possess a functional FLO8 gene. We show that disrupting the ACE2 transcription factor results in the production of pseudohyphae in a flo8-1 background. Disrupting the CTS1 (chitinase) gene also produces pseudohyphal growth in this background, but at a reduced level. Invasion of solid media by haploid and diploid cells is increased in ACE2 disruptions, but the diploids adhere poorly to the agar. Sigma1278b-derived strains, which generally produce pseudohyphae, have about 30-fold lower chitinase activity than other strains. PMID:9745020

King, L; Butler, G

1998-09-01

315

How wing kinematics affect power requirements and aerodynamic force production in a robotic bat wing.  

PubMed

Bats display a wide variety of behaviors that require different amounts of aerodynamic force. To control and modulate aerodynamic force, bats change wing kinematics, which, in turn, may change the power required for wing motion. There are many kinematic mechanisms that bats, and other flapping animals, can use to increase aerodynamic force, e.g. increasing wingbeat frequency or amplitude. However, we do not know if there is a difference in energetic cost between these different kinematic mechanisms. To assess the relationship between mechanical power input and aerodynamic force output across different isolated kinematic parameters, we programmed a robotic bat wing to flap over a range of kinematic parameters and measured aerodynamic force and mechanical power. We systematically varied five kinematic parameters: wingbeat frequency, wingbeat amplitude, stroke plane angle, downstroke ratio, and wing folding. Kinematic values were based on observed values from free flying Cynopterus brachyotis, the species on which the robot was based. We describe how lift, thrust, and power change with increases in each kinematic variable. We compare the power costs associated with generating additional force through the four kinematic mechanisms controlled at the shoulder, and show that all four mechanisms require approximately the same power to generate a given force. This result suggests that no single parameter offers an energetic advantage over the others. Finally, we show that retracting the wing during upstroke reduces power requirements for flapping and increases net lift production, but decreases net thrust production. These results compare well with studies performed on C. brachyotis, offering insight into natural flight kinematics. PMID:24851830

Bahlman, Joseph W; Swartz, Sharon M; Breuer, Kenneth S

2014-06-01

316

Blastocyst rate of in vitro embryo production in sheep is affected by season.  

PubMed

Summary It has been reported that the number and quality of in vitro produced embryos is season related. This study was conducted to assess the effect of season on cleavage, blastocyst and lambing rates of in vitro produced ovine embryos during 3 years of collection data. Ovaries of Sarda sheep were collected from a slaughterhouse. In total, 5035 oocytes were recovered and matured in TCM-199 with 4 mg/ml bovine serum albumin (BSA), 100 ?M cysteamine, 0.3 mM Na pyruvate, 0.1 UI/ml recombinant follicle-stimulating hormone (r-FSH), 0.1 UI/ml recombinant luteinising hormone (r-LH), and 1 ?g/ml estradiol-17?. Matured oocytes were fertilized with fresh semen in synthetic oviductal fluid (SOF) with 20% heat inactivated estrous sheep serum. The presumptive zygotes were cultured for 6-7 days (blastocyst stage) in SOF medium supplemented with 1% Basel Medium Eagle (BME), 1% Minimum Essential Medium, 1 mM glutamine and 8 mg/ml fatty acid-free BSA. The embryos produced were vitrified and a total of 165 blastocysts (80 from the breeding season and 85 from the anoestrous season) were transferred in pairs into recipient ewes during the reproductive period. There were no significant differences in cleavage rates between seasons in any of the 3 years examined (84% versus 83%, 81% versus 80% and 80% versus 79%, respectively). The blastocyst rate varied significantly between seasons in 2005 and 2007 (P < 0.05), and in 2006 (P < 0.001). There were no differences in pregnancy and lambing rates between embryos during anoestrous versus during the breeding season. In conclusion, only the blastocyst rate appeared to have been affected by season, possibly due to variation in the number of developmentally competent oocytes. PMID:23458093

Mara, L; Sanna, D; Casu, S; Dattena, M; Muñoz, I M Mayorga

2014-08-01

317

Chiral spin torque at magnetic domain walls  

NASA Astrophysics Data System (ADS)

Spin-polarized currents provide a powerful means of manipulating the magnetization of nanodevices, and give rise to spin transfer torques that can drive magnetic domain walls along nanowires. In ultrathin magnetic wires, domain walls are found to move in the opposite direction to that expected from bulk spin transfer torques, and also at much higher speeds. Here we show that this is due to two intertwined phenomena, both derived from spin-orbit interactions. By measuring the influence of magnetic fields on current-driven domain-wall motion in perpendicularly magnetized Co/Ni/Co trilayers, we find an internal effective magnetic field acting on each domain wall, the direction of which alternates between successive domain walls. This chiral effective field arises from a Dzyaloshinskii-Moriya interaction at the Co/Pt interfaces and, in concert with spin Hall currents, drives the domain walls in lock-step along the nanowire. Elucidating the mechanism for the manipulation of domain walls in ultrathin magnetic films will enable the development of new families of spintronic devices.

Ryu, Kwang-Su; Thomas, Luc; Yang, See-Hun; Parkin, Stuart

2013-07-01

318

Frequency-tunable perpendicular spin torque oscillator  

NASA Astrophysics Data System (ADS)

We present an experimental study on the frequency tunability of a perpendicular spin transfer torque oscillator with a perpendicularly magnetized (Co/Pd)5 reference electrode and a Co/(Pd/Co)4 composite oscillating layer of a giant magnetoresistive stack. A current-perpendicular-to-plane magnetoresistance ratio of 2.55% is obtained for the stack. Spin transfer torque induced steady oscillation with a narrow line-width has been obtained with direct current injection. As the injected dc current level is varied from 4.5 to 8.5 mA under a small constant applied field, the oscillation frequency increases from 5 to 6.2 GHz and back to 5.8 GHz. The oscillation with the narrowest linewidth occurs at the injection current magnitude at which the highest oscillation amplitude is also obtained. Micromagnetic modeling suggests that a nanomagnet above its critical single domain size is subjected to higher order spin wave generation at large current density. The spatial inhomogenity created across the nanomagnet can account for the drop in its oscillation frequency at relatively large injection currents.

Sim, C. H.; Moneck, M.; Liew, T.; Zhu, J.-G.

2012-04-01

319

Electromagnetic force and torque in ponderable media.  

PubMed

Maxwell's macroscopic equations combined with a generalized form of the Lorentz law of force are a complete and consistent set of equations. Not only are these five equations fully compatible with special relativity, they also conform with conservation laws of energy, momentum, and angular momentum. We demonstrate consistency with the conservation laws by showing that, when a beam of light enters a magnetic dielectric, a fraction of the incident linear (or angular) momentum pours into the medium at a rate determined by the Abraham momentum density, E x H/c(2), and the group velocity V(g) of the electromagnetic field. The balance of the incident, reflected, and transmitted momenta is subsequently transferred to the medium as force (or torque) at the leading edge of the beam, which propagates through the medium with velocity V(g). Our analysis does not require "hidden" momenta to comply with the conservation laws, nor does it dissolve into ambiguities with regard to the nature of electromagnetic momentum in ponderable media. The linear and angular momenta of the electromagnetic field are clearly associated with the Abraham momentum, and the phase and group refractive indices (n(p) and n(g)) play distinct yet definitive roles in the expressions of force, torque, and momentum densities. PMID:18795019

Mansuripur, Masud

2008-09-15

320

The Torque at a Lindblad Vertical Resonance  

NASA Astrophysics Data System (ADS)

A fairly uniform, rapidly and differentially rotating disk of rarely colliding particles (when the frequency of interparticle collisions is much smaller than the local orbital frequency) in a planet-moon system is considered. A moon causes a number of orbital resonant effects in this continuous, viscous (through ordinary collisions) disk. In the frame of hydrodynamical theory, the gravitational torques exerted by an exterior moon on particles at an inner Lindblad horizontal resonance and corresponding vertical resonance are estimated. It is shown that the torques are negative at these resonances, so gaps in the disk near each resonance may be created. The latter result can be used to provide a viable clue to solving the puzzle of narrow, dense, and widely separated rings of Uranus. The model advocated suggests that the Uranian ring orbits have a close connection with the small moons of the planet that are interior to the orbit of Miranda, from Cordelia to Mab, discovered by Voyager 2 imaging observations in 1986.

Griv, Evgeny

2007-08-01

321

Chiral spin torque at magnetic domain walls.  

PubMed

Spin-polarized currents provide a powerful means of manipulating the magnetization of nanodevices, and give rise to spin transfer torques that can drive magnetic domain walls along nanowires. In ultrathin magnetic wires, domain walls are found to move in the opposite direction to that expected from bulk spin transfer torques, and also at much higher speeds. Here we show that this is due to two intertwined phenomena, both derived from spin-orbit interactions. By measuring the influence of magnetic fields on current-driven domain-wall motion in perpendicularly magnetized Co/Ni/Co trilayers, we find an internal effective magnetic field acting on each domain wall, the direction of which alternates between successive domain walls. This chiral effective field arises from a Dzyaloshinskii-Moriya interaction at the Co/Pt interfaces and, in concert with spin Hall currents, drives the domain walls in lock-step along the nanowire. Elucidating the mechanism for the manipulation of domain walls in ultrathin magnetic films will enable the development of new families of spintronic devices. PMID:23770808

Ryu, Kwang-Su; Thomas, Luc; Yang, See-Hun; Parkin, Stuart

2013-07-01

322

Dynamics of a split torque helicopter transmission  

NASA Astrophysics Data System (ADS)

Split torque designs, proposed as alternatives to traditional planetary designs for helicopter main rotor transmissions, can save weight and be more reliable than traditional designs. This report presents the results of an analytical study of the system dynamics and performance of a split torque gearbox that uses a balance beam mechanism for load sharing. The Lagrange method was applied to develop a system of equations of motion. The mathematical model includes time-varying gear mesh stiffness, friction, and manufacturing errors. Cornell's method for calculating the stiffness of spur gear teeth was extended and applied to helical gears. The phenomenon of sidebands spaced at shaft frequencies about gear mesh fundamental frequencies was simulated by modeling total composite gear errors as sinusoid functions. Although the gearbox has symmetric geometry, the loads and motions of the two power paths differ. Friction must be considered to properly evaluate the balance beam mechanism. For the design studied, the balance beam is not an effective device for load sharing unless the coefficient of friction is less than 0.003. The complete system stiffness as represented by the stiffness matrix used in this analysis must be considered to precisely determine the optimal tooth indexing position.

Krantz, Timothy L.

1994-06-01

323

Investigation and Improvement of Torque Response of Control System Based on Direct Torque Control in Interior Permanent Magnet Synchronous Motors  

NASA Astrophysics Data System (ADS)

In this study, we investigate the torque response of a control system that is based on the direct torque control (DTC) principle for an interior permanent magnet synchronous motor (IPMSM). We also propose a gain-scheduling method for improving the torque response. Reference flux vector calculation (RFVC) DTC is used in this study. In RFVC DTC, a PI controller is used for torque control; this is in contrast to the use of the hysteresis comparator and switching table in basic DTC. In this paper, we present the relationship between the torque response and the gain of the PI controller. This relationship is derived by using the transfer function of the torque control loop. In this study, we also examine the difference between the torque responses of two motors that have different machine parameters. The proposed method can be used to realize a torque response that is independent of the operating torque. The simulation results and experimental results presented in this paper show the validity of the derived relationship as well as the effectiveness of the proposed method.

Inoue, Yukinori; Morimoto, Shigeo; Sanada, Masayuki

324

Influence of joint angle on EMG-torque model during constant-posture, quasi-constant-torque contractions.  

PubMed

Electromyogram (EMG)-torque modeling is of value to many different application areas, including ergonomics, clinical biomechanics and prosthesis control. One important aspect of EMG-torque modeling is the ability to account for the joint angle influence. This manuscript describes an experimental study which relates the biceps/triceps surface EMG of 12 subjects to elbow torque at seven joint angles (spanning 45-135°) during constant-posture, quasi-constant-torque contractions. Advanced EMG amplitude (EMG?) estimation processors (i.e., whitened, multiple-channel) were investigated and three non-linear EMG?-torque models were evaluated. When EMG-torque models were formed separately for each of the seven distinct joint angles, a minimum "gold standard" error of 4.23±2.2% MVCF90 resulted (i.e., error relative to maximum voluntary contraction at 90° flexion). This model structure, however, did not directly facilitate interpolation across angles. The best model which did so (i.e., parameterized the angle dependence), achieved an error of 4.17±1.7% MVCF90. Results demonstrated that advanced EMG? processors lead to improved joint torque estimation. We also contrasted models that did vs. did not account for antagonist muscle co-contraction. Models that accounted for co-contraction estimated individual flexion muscle torques that were ?29% higher and individual extension muscle torques that were ?68% higher. PMID:23932797

Liu, Pu; Liu, Lukai; Martel, Francois; Rancourt, Denis; Clancy, Edward A

2013-10-01

325

How technology and price affect US tight gas potential. Part 1. Technology of tight gas production  

SciTech Connect

The tight gas resource in the US currently is estimated at 900 tcf, of which 600 tcf is considered technically recoverable. This gas is found in basins that cover a prospective area of one million square miles (one million sections). Of these, ca 120,000 sections are potentially productive. The tight gas picture is composed of many different and often complex reservoirs, ranging from the shallow horizons of the Northern Great Plains to the deep formations of the Rocky Mountains. These reservoirs range from the blanket-like formations that cover wide geographical areas to the highly lenticular zones such as those common to the Mesa Verde. The one thing they have in common is microdarcy permeabilities. A good perspective of the challenge is obvious when such permeability values are realized to be similar to that of cement normally used for oil and gas well casing strings. The advanced technology presumes improved exploration knowledge, longer fractures, higher fracture conductivity, and a higher density of well development. Advanced technology is particularly necessary for lenticular reservoirs which contain ca 40% of the recoverable gas.

Veatch, R.W. Jr.; Baker, O.

1983-01-01

326

Purine metabolizing capability of Enterobacter agglomerans affects volatiles production and attractiveness to Mexican fruit fly.  

PubMed

We investigated two strains of Enterobacter agglomerans that differ in their ability to metabolize uric acid for (1) attractiveness to sugar-fed Mexican fruit flies, and (2) production of volatile chemicals that may be responsible for the attractiveness. The two strains were cultured on a medium that contained uric acid as the primary nitrogen source to simulate bird feces, a natural substrate for this bacterium. Active cultures of both strains were more attractive than uninoculated uric acid medium to both sexes of sugar-fed flies in wind-tunnel bioassays. The uricase(+) strain was more attractive than the uricase(-) strain to males and to females <9 days old, but not to older females. Volatiles found by solid-phase microextraction in greater amounts in headspace above active cultures of both strains than above uninoculated medium were ammonia, dimethyldisulfide, 3-methylbutanol, 2-phenylethanol, 2,5-dimethylpyrazine, and trimethylpyrazine. The uricase(+) strain produced more ammonia, dimethyldisulfide, and trimethylpyrazine than the uricase(-) strain. An additional chemical, 3-hydroxybutanone, appears to be produced exclusively by the uricase(+) strain. The uricase(-) strain produced more 2-phenylethanol than the uricase(+) strain. Differences in volatiles are consistent with the generally greater attractiveness of the uricase(+) strain compared with the uricase(-) strain as ammonia, 3-hydroxybutanone, and trimethylpyrazine have been demonstrated attractive to sugar-fed Mexican fruit flies. PMID:12371809

Robacker, David C; Lauzon, Carol R

2002-08-01

327

Daylength and temperature during seed production interactively affect adaptive performance of Picea abies progenies.  

PubMed

Adaptive traits in Picea abies (Norway spruce) progenies are influenced by the maternal temperatures during seed production. Here, we have extended these studies by testing the effects of maternal photoperiod and temperature on phenology and frost hardiness on progenies. Using eight phytotron rooms, seeds from three unrelated crosses were made in an environmental 2 x 2 factorial combination of long and short days and high and low temperatures. The progenies were then forced to cease growth rapidly at the end of the first growing season. An interactive memory effect was expressed the second growth season. Progenies from high temperature and short days, and from low temperatures and long days, started growth later in spring, ceased shoot growth later in summer, grew taller and were less frost hardy in the autumn than their full siblings from low temperatures and short days, and from high temperatures and long days. Norway spruce has developed a memory mechanism, regulating adaptive plasticity by photoperiod and temperature, which could counteract harmful effects of a rapidly changing climate. PMID:16313642

Johnsen, Oystein; Daehlen, Ola Gram; Ostreng, Geir; Skrøppa, Tore

2005-12-01

328

Bacillus cereus and Bacillus thuringiensis spores in Korean rice: Prevalence and toxin production as affected by production area and degree of milling.  

PubMed

We determined the prevalence of and toxin production by Bacillus cereus and Bacillus thuringiensis in Korean rice as affected by production area and degree of milling. Rough rice was collected from 64 farms in 22 agricultural areas and polished to produce brown and white rice. In total, rice samples were broadly contaminated with B. cereus spores, with no effect of production area. The prevalence and counts of B. cereus spores declined as milling progressed. Frequencies of hemolysin BL (HBL) production by isolates were significantly (P ? 0.01) reduced as milling progressed. This pattern corresponded with the presence of genes encoding the diarrheal enterotoxins. The frequency of B. cereus isolates positive for hblC, hblD, or nheB genes decreased as milling progressed. Because most B. cereus isolates from rice samples contained six enterotoxin genes, we concluded that B. cereus in rice produced in Korea is predominantly of the diarrheagenic type. The prevalence of B. thuringiensis in rice was significantly lower than that of B. cereus and not correlated with production area. All B. thuringiensis isolates were of the diarrheagenic type. This study provides information useful for predicting safety risks associated with B. cereus and B. thuringiensis in rough and processed Korean rice. PMID:24929722

Kim, Booyoung; Bang, Jihyun; Kim, Hoikyung; Kim, Yoonsook; Kim, Byeong-Sam; Beuchat, Larry R; Ryu, Jee-Hoon

2014-09-01

329

Factors Affecting Process Temperature and Biogas Production in Small-scale Rural Biogas Digesters in Winter in Northern Vietnam.  

PubMed

This study investigated the main factors influencing digester temperature and methods to reduce heat losses during the cold season in the subtropics. Four composite digesters (two insulated and two uninsulated) were buried underground to measure their internal temperature (°C) at a depth of 140 cm and 180 cm, biogas production and methane (CH4) concentration in biogas from August to February. In parallel the temperature of the air (100 cm above ground), in the slurry mixing tank and in the soil (10, 100, 140, and 180 cm depth) was measured by thermocouple. The influent amount was measured daily and the influent chemical composition was measured monthly during the whole experimental period. Seasonal variations in air temperature significantly affected the temperature in the soil, mixing tank and digester. Consequently, biogas production, which is temperature dependent, was influenced by the season. The main factors determining the internal temperature in the digesters were insulation with Styrofoam, air temperature and temperature of slurry in the mixing tank. Biogas production is low due to the cold climate conditions in winter in Northern Vietnam, but the study proved that storing slurry in the mixing tank until its temperature peak at around 14:00 h will increase the temperature in the digester and thus increase potential biogas production. Algorithms are provided linking digester temperature to the temperature of slurry in the mixing tank. PMID:25050049

Pham, C H; Vu, C C; Sommer, S G; Bruun, S

2014-07-01

330

Factors Affecting Process Temperature and Biogas Production in Small-scale Rural Biogas Digesters in Winter in Northern Vietnam  

PubMed Central

This study investigated the main factors influencing digester temperature and methods to reduce heat losses during the cold season in the subtropics. Four composite digesters (two insulated and two uninsulated) were buried underground to measure their internal temperature (°C) at a depth of 140 cm and 180 cm, biogas production and methane (CH4) concentration in biogas from August to February. In parallel the temperature of the air (100 cm above ground), in the slurry mixing tank and in the soil (10, 100, 140, and 180 cm depth) was measured by thermocouple. The influent amount was measured daily and the influent chemical composition was measured monthly during the whole experimental period. Seasonal variations in air temperature significantly affected the temperature in the soil, mixing tank and digester. Consequently, biogas production, which is temperature dependent, was influenced by the season. The main factors determining the internal temperature in the digesters were insulation with Styrofoam, air temperature and temperature of slurry in the mixing tank. Biogas production is low due to the cold climate conditions in winter in Northern Vietnam, but the study proved that storing slurry in the mixing tank until its temperature peak at around 14:00 h will increase the temperature in the digester and thus increase potential biogas production. Algorithms are provided linking digester temperature to the temperature of slurry in the mixing tank.

Pham, C. H.; Vu, C. C.; Sommer, S. G.; Bruun, S.

2014-01-01

331

Oxidation of dimethylselenide by ??MnO2: Oxidation product and factors affecting oxidation rate  

USGS Publications Warehouse

Volatile dimethylselenide (DMSe) was transformed to a nonvolatile Se compound in a ??-MnO2 suspension. The nonvolatile product was a single compound identified as dimethylselenoxide based on its mass spectra pattern. After 24 h, 100% of the DMSe added to a ??-MnO2 suspension was converted to nonpurgable Se as opposed to 20%, 18%, and 4% conversion for chromate, permanganate, and the filtrate from the suspension, respectively. Manganese was found in solution after reaction. These results imply that the reaction between manganese oxide and DMSe was a heterogeneous redox reaction involving solid phase ??-MnO2 and solution phase DMSe. Oxidation of DMSe to dimethylselenoxide [OSe(CH3)2] by a ??-MnO2 suspension appears to be first order with respect to ??-MnO2, to DMSe, and to hydrogen ion with an overall rate law of d[OSe(CH3)2 ]/dt = 95 M-2 min-1 [MnO2]1[DMSe]1[H+]1 for the MnO2 concentration range of 0.89 ?? 10-3 - 2.46 ?? 10-3 M, the DMSe concentration range of 3.9 ?? 10-7 - 15.5 ?? 10-7 M Se, and a hydrogen ion concentation range of 7.4 ?? 10-6 -9.5 ?? 10-8 M. A general surface site adsorption model is consistent with this rate equation if the uncharged |OMnOH is the surface adsorption site. DMSe acts as a Lewis base, and the manganese oxide surface acts as a Lewis acid. DMSe adsorption to |OMnOH can be viewed as a Lewis acid/ base complex between the largely p orbitals of the DMSe lone pair and the unoccupied eg orbitals on manganese oxide. For such a complex, frontier molecular orbital theory predicts electron transfer to occur via an inner-sphere complex between the DMSe and the manganese oxide. ?? 1995 American Chemical Society.

Wang, B.; Burau, R. G.

1995-01-01

332

Nitrate leaching to subsurface drains as affected by drain spacing and changes in crop production system.  

PubMed

Subsurface drainage is a beneficial water management practice in poorly drained soils but may also contribute substantial nitrate N loads to surface waters. This paper summarizes results from a 15-yr drainage study in Indiana that includes three drain spacings (5, 10, and 20 m) managed for 10 yr with chisel tillage in monoculture corn (Zea mays L.) and currently managed under a no-till corn-soybean [Glycine max (L.) Merr.] rotation. In general, drainflow and nitrate N losses per unit area were greater for narrower drain spacings. Drainflow removed between 8 and 26% of annual rainfall, depending on year and drain spacing. Nitrate N concentrations in drainflow did not vary with spacing, but concentrations have significantly decreased from the beginning to the end of the experiment. Flow-weighted mean concentrations decreased from 28 mg L(-1) in the 1986-1988 period to 8 mg L(-1) in the 1997-1999 period. The reduction in concentration was due to both a reduction in fertilizer N rates over the study period and to the addition of a winter cover crop as a "trap crop" after corn in the corn-soybean rotation. Annual nitrate N loads decreased from 38 kg ha(-1) in the 1986-1988 period to 15 kg ha(-1) in the 1997-1999 period. Most of the nitrate N losses occurred during the fallow season, when most of the drainage occurred. Results of this study underscore the necessity of long-term research on different soil types and in different climatic zones, to develop appropriate management strategies for both economic crop production and protection of environmental quality. PMID:15356241

Kladivko, E J; Frankenberger, J R; Jaynes, D B; Meek, D W; Jenkinson, B J; Fausey, N R

2004-01-01

333

Behavior and milk production of buffalo cows as affected by housing system.  

PubMed

To verify the effect of 2 housing systems (with and without a pool and an ample outdoor lot) on behavior and milk yield, 45 lactating buffalo cows were group-housed in a free stall open-sided barn with concrete floor where they received 10 m(2)/head as space allowance (group NP); 43 cows were group-housed in a similar barn, but had access to an outdoor yard (36 m(2)/head) and a concrete pool of 208 m(2) (group WP). Animals were subjected to 8 sessions of instantaneous scan sampling at approximately 10-d intervals. Behavioral variables were expressed as proportions of subjects observed in each category of posture and activity. In addition, rapid behaviors such as agonistic, social, and reproductive interactions, social licking, and self-grooming were recorded continuously. These variables were expressed as number of interactions per animal. At the end of each hour of observation, temperature and relative humidity were recorded. In WP the proportion of animals observed wallowing was 0.476 +/- 0.034, whereas lower proportions were observed standing (0.389 +/- 0.029) or lying (0.141 +/- 0.021) outside the pool. In NP the proportions of animals observed standing and lying were 0.452 +/- 0.042 and 0.548 +/- 0.042, respectively. A significant relationship between mean temperatures recorded on observation days and proportion of animals in the pool was observed (r(s) = 0.41). Fewer animals from group WP were observed idling compared with buffaloes from group NP (0.44 +/- 0.024 vs. 0.509 +/- 0.024, respectively), whereas more WP animals were involved in investigative activities than NP cows (0.099 +/- 0.009 vs. 0.042 +/- 0.009, respectively). A greater number of social interactions (sniffing and nuzzling) and social lickings were observed in group WP than in group NP (0.120 +/- 0.010 vs. 0.067 +/- 0.010, and 0.151 +/- 0.018 vs. 0.090 +/- 0.018, respectively). The WP buffalo cows had a greater milk yield than NP cows (11.73 +/- 0.31 vs. 10.78 +/- 0.28 kg/d, respectively), whereas no differences between groups were observed for protein (4.86 +/- 0.04 vs. 4.80 +/- 0.03% for WP and NP, respectively) and fat contents (8.49 +/- 0.14 vs. 8.38 +/- 0.13% for WP and NP, respectively). We conclude that the provision of a pool and an ample outdoor paddock can have beneficial effects on welfare and milk production of buffaloes. PMID:19233783

De Rosa, G; Grasso, F; Braghieri, A; Bilancione, A; Di Francia, A; Napolitano, F

2009-03-01

334

Developing an excavation torque model for dense cohesionless soils  

Microsoft Academic Search

Torque encountered during the rotary excavation of soils (e.g., when using the DJM method for deep soft ground improvement) poses a serious detrimental effect not only to the excavating machines but also to the viability of a project as a whole. Consequently, this research investigates ways and means of realizing the reduction of torque encountered during the excavation of cohesionless

Nathaniel Ochieng Ambassah; Ryoichi Fukagawa

2005-01-01

335

Core shape optimization for cogging torque reduction of BLDC motor  

Microsoft Academic Search

The cogging torque in the small brushless DC (BLDC) motors used in the digital versatile disk (DVD) driving system or hard disk drive (HDD) system can cause some serious vibration problems. In this paper, some core shapes that reduce cogging torque are found by using a reluctance network method (RNM) for magnetic field analysis and a genetic algorithm (GA) for

Ki-Jin Han; Han-Sam Cho; Dong-Hyeok Cho; Hyun-Rae Cho; Hae-Seok Lee; Hyun-Kyo Jung

1999-01-01

336

Analysis of torque ripple in BLDC motor with commutation time  

Microsoft Academic Search

Torque ripple generated in the commutation period is the main drawback of the brushless DC (BLDC) motor, which deteriorates its precision. Many methods to solve this problem have been studied. In many control methods, torque ripple reduction was considered at the point of current control, which means that if current can be controlled properly, the BLDC motor does not produce

Byoung-Hee Kang; Choel-Ju Kim; Hyung-Su Mok; Gyu-Ha Choe

2001-01-01

337

Intelligent built-in torque sensor for harmonic drive systems  

Microsoft Academic Search

The unique performance features of harmonic drives, such as high gear ratios and high torque capacities in a compact geometry, justify their widespread industrial application especially in many electrically actuated robot manipulators. In many robotic control strategies it is assumed that the actuator is acting as a torque source, and in order to implement such algorithms it is necessary to

Hamid D. Taghirad; P. R. Belanger

1999-01-01

338

Ripple compensation for torque sensors built into harmonic drives  

Microsoft Academic Search

Harmonic drives include a mechanically flexible component which transmits load torque, and therefore, a torque sensor can be built into harmonic drives by cementing strain gages on a flexible component of the gear. However, a periodic sensing error called ripple is generated by deformation of a flexible component during the gear operation. The ripple signal cannot be sufficiently compensated by

Ivan Godler; Tamotsu Ninomiya; Masashi Horiuchi

2001-01-01

339

Torque meter aids study of hysteresis motor rings  

NASA Technical Reports Server (NTRS)

Torque meter, simulating hysteresis motor operation, allows rotor ring performance characteristics to be analyzed. The meter determines hysteresis motor torque and actual stresses of the ring due to its mechanical situation and rotation, aids in the study of asymmetries or defects in motor rings, and measures rotational hysteresis.

Cole, M.

1967-01-01

340

Fuzzy sliding mode direct torque control for PMSM  

Microsoft Academic Search

A fuzzy sliding mode controller for permanent magnet synchronous machine (PMSM) is investigated in this paper, in which direct torque control (DTC) concept, fuzzy variable structure control and space vector modulation (SVM) are integrated to achieve high performance. It features in very low flux and torque ripple, strong robustness and fixed switching frequency. The theoretical analyses for the proposed fuzzy

Rui Guo; Xiuping Wang; Junyou Zhao; Wenbo Yu

2011-01-01

341

Predictive direct torque control for the PM synchronous machine  

Microsoft Academic Search

This paper shows that a predictive digital control combined with the principle of direct torque control (DTC) leads to an excellent dynamic behavior of the synchronous machine with surface-mounted permanent magnets and is a real alternative to the classical field-orientated control. The advantages are a DTC control scheme with constant switching frequency and a predictable torque ripple. The settling times

Mario Pacas; Jürgen Weber

2005-01-01

342

Precise Magnetic Torque Measurements on Single Crystals of Iron  

Microsoft Academic Search

A rugged balance of sufficiently high sensitivity and a rotating magnet capable of producing a field of over 3000 oersteds are used to make magnetic torque curves. The equations for the torque curve of a single crystal disk of any orientation whatsoever are derived on the assumption that the magnetic anisotropy is adequately described by a single constant. Furthermore, a

L. P. Tarasov; F. Bitter

1937-01-01

343

Gas torque effect for molecular combinations of hydrogen and deuterium  

Microsoft Academic Search

A heated cylinder immersed in a rarefield gas experiences an axial torque when an axial magnetic field is applied. Measurements of this torque as a function of gas pressure and field intensity were made for H2, D2 and HD.

G. G. Scott; H. W. Sturner; R. M. Williamson

1967-01-01

344

Tidal Torques: A Critical Review of Some Techniques.  

National Technical Information Service (NTIS)

We review some techniques employed in the studies of torques due to bodily tides, and explain why the MacDonald formula for the tidal torque is valid only in the zeroth order of the eccentricity divided by the quality factor, while its time-average is val...

J. G. Williams M. Efroimsky

2009-01-01

345

Speed control of electrical machines: unknown load torque case  

Microsoft Academic Search

The problem of specifying a desired torque trajectory to achieve speed tracking in passivity-based control of induction motors is addressed. This paper presents a solution to the problem that does not require an acceleration measurement nor knowledge of the load torque. To prove the main result a variant of Sontag's input to state stability is used

H. A. A. Fattah; K. A. Loparo

2001-01-01

346

Harmonic Torque Calculation of Induction Motors Using Electromagnetic Field Analysis  

NASA Astrophysics Data System (ADS)

In this paper, we investigate effects of harmonic electromagnetic field to torque characteristics of induction motors from both side of experiment and electromagnetic field analysis. The characteristics of two kinds of the aluminum cage three-phase induction motors are measured and calculated. One is with the closed rotor slots. The other is semi-closed. In the experiment, the negative torque at synchronous speed is measured by driving the induction motor by the synchronous permanent magnet motor. The total torque at load condition is also measured by the torque detector. In the analysis, the harmonic magnetic fields, the harmonic losses and the harmonic torques at each time and space harmonic order are calculated using the nonlinear time-stepping finite element method to clarify the mechanism of the harmonic torque generation. The measured and the calculated results agree well. It is clarified that the negative torque caused by the slot harmonics at the rated load condition is not negligible and that the negative torque is mainly generated by the harmonic core losses.

Yamazaki, Katsumi; Haruishi, Yoshihisa; Ara, Takahiro

347

Fuzzy logic direct torque control for permanent magnet synchronous motors  

Microsoft Academic Search

An outstanding feature of the conventional direct torque control (DTC) for permanent magnet synchronous motors (PMSM) is its fast dynamic response. However, large torque and flux linkage ripples are generated because of the use of the hysteresis controllers and the crude position signals based on six 60° angular regions for selecting the space voltage vectors. This paper proposes a fuzzy

Dan Sun; Yikang He; Jian Guo Zhu

2004-01-01

348

Milk production traits of beef cows as affected by horn fly count and sire breed type.  

PubMed

Horn fly infestations negatively impact economic traits of beef cattle. Our objective was to determine the impact of horn flies on beef cattle milk yield and quality. Cows (n = 53) were derived from Brangus dams and sired by Bonsmara (n = 7), Brangus (n = 13), Charolais (n = 8), Gelbvieh (n = 5), Hereford (n = 12), and Romosinuano (n = 8) bulls. Horn fly counts and estimates of milk yield and quality were recorded monthly from May through October on individual cows. Data for milk yield and quality and horn fly count were analyzed by mixed model least squares using a linear model including sire breed, cow in sire breed, month, and month × sire breed. Effects of horn fly count on milk yield and quality were estimated by analysis of covariance using log horn fly count and log horn fly count × sire breed. Horn fly counts varied by month (P < 0.0001), with lowest population recorded in May (99 flies) and peaked in August (520 flies). Bonsmara and Gelbvieh sired cows had greater (P < 0.05) milk yield compared to Hereford sired cows (8.75 and 8.62 vs. 6.02 kg/d, respectively). Milk yield from Charolais, Romosinuano, and Brangus sired cows was intermediate (7.28, 7.00, and 7.06 kg/d, respectively). Regression of milk yield on fly count differed (P < 0.05) among sire breeds. Milk yield was reduced (P < 0.05) by 0.99 and 0.64 kg/d per unit increase in log horn fly count in Gelbvieh and Bonsmara sired cows. Regression coefficient for milk yield on log horn fly count was reduced (P < 0.01) in Gelbvieh sired cows when compared with Brangus, Charolais, Hereford, and Romosinuano sired cows, and coefficients for Bonsmara sired cows were reduced (P < 0.05) in comparison to Brangus sired cows. Increases in log fly count were associated with decreases (P < 0.05) in milk fat, solids-not-fat, and milk urea nitrogen. Milk yield was reduced (P < 0.05) by increased fly numbers depending on month of lactation and interaction with log horn fly count. In May, June, and July milk yield was reduced 0.72, 0.68, and 0.71 kg/d per unit increase in log horn fly count. Our results indicate that horn fly infestations reduce milk yield and quality of spring-calving beef cows depending on sire breed and month of lactation. Development of sustainable beef production systems may include selecting breed types whose milk yield and quality is less influenced by horn flies, allowing for better expression of genetic potential for milk yield in nutritionally challenging environments. PMID:24492544

Mays, A R; Brown, M A; von Tunglen, D L; Rosenkrans, C F

2014-03-01

349

Optimal rotor design for reducing the partial demagnetization effect and cogging torque in spoke type PM motor  

NASA Astrophysics Data System (ADS)

This paper proposes an optimized rotor pole shape that can effectively reduce the partial demagnetization effect and cogging torque. First, for reducing the peak amplitude of the external field that directly affects the partial demagnetization on the permanent magnets in spoke-type permanent magnet motor, we conduct a variation of core shape and insertion of a barrier. Second, with the rotor shape obtained by the first processes for reducing the partial demagnetization effect, another part of the rotor pole is varied to make better sinusoidal distributed air gap flux density to reduce the cogging torque. In the process of designing the rotor pole shape, a steepest descent method and a response surface method are applied for improving convergence. By using the finite element method, we show that the optimized rotor pole shape drastically reduces the effect of the partial demagnetization and cogging torque.

Hwang, Kyu-Yun; Yang, Byoung-Yull; Rhyu, Se-Hyun; Kim, Byung-Taek; Kim, Dae-Kyong; Rhee, Sang-Bong; Kwon, Byung-Il

2009-04-01

350

Torque Sensor Based on Tunnel-Diode Oscillator  

NASA Technical Reports Server (NTRS)

A proposed torque sensor would be capable of operating over the temperature range from 1 to 400 K, whereas a typical commercially available torque sensor is limited to the narrower temperature range of 244 to 338 K. The design of this sensor would exploit the wide temperature range and other desirable attributes of differential transducers based on tunnel-diode oscillators as described in "Multiplexing Transducers Based on Tunnel-Diode Oscillators". The proposed torque sensor would include three flexural springs that would couple torque between a hollow outer drive shaft and a solid inner drive shaft. The torque would be deduced from the torsional relative deflection of the two shafts, which would be sensed via changes in capacitances of two capacitors defined by two electrodes attached to the inner shaft and a common middle electrode attached to the outer shaft.

Chui, Talso; Young, Joseph

2008-01-01

351

Torque Expressions and Equivalent Circuits for Salient Pole Synchronous Machines  

NASA Astrophysics Data System (ADS)

Two different torque expressions are proposed for salient pole synchronous machines. One is the traditional torque-voltage equation. The other is a torque-current equation and has been recently used for permanent magnet synchronous motors. Both these expressions have two terms. According to a general interpretation, one of the terms represents the magnet torque and the second term represents the reluctance torque. However, the corresponding terms in these two expressions do not give the same value when the expressions are used for an interior permanent-magnet synchronous motor. The aim of this study is to demonstrate this disagreement and identify the reason for the same by using two different equivalent circuits for salient pole synchronous machines.

Kondo, Minoru

352

Design of digital load torque observer in hybrid electric vehicle  

NASA Astrophysics Data System (ADS)

In hybrid electric vehicle, engine begain to work only when motor was in high speed in order to decrease tail gas emission. However, permanent magnet motor was sensitive to its load, adding engine to the system always made its speed drop sharply, which caused engine to work in low efficiency again and produced much more environment pollution. Dynamic load torque model of permanent magnet synchronous motor is established on the basic of motor mechanical equation and permanent magnet synchronous motor vector control theory, Full- digital load torque observer and compensation control system is made based on TMS320F2407A. Experiment results prove load torque observer and compensation control system can detect and compensate torque disturbing effectively, which can solve load torque disturbing and decrease gas pollution of hybrid electric vehicle.

Sun, Yukun; Zhang, Haoming; Wang, Yinghai

2008-12-01

353

Torque Splitting by a Concentric Face Gear Transmission  

NASA Technical Reports Server (NTRS)

Tests of a 167 Kilowatt (224 Horsepower) split torque face gearbox were performed by the Boeing Company in Mesa, Arizona, while working under a Defense Advanced Research Projects Agency (DARPA) Technology Reinvestment Program (TRP). This paper provides a summary of these cooperative tests, which were jointly funded by Boeing and DARPA. Design, manufacture and testing of the scaled-power TRP proof-of-concept (POC) split torque gearbox followed preliminary evaluations of the concept performed early in the program. The split torque tests were run using 200 N-m (1767 in-lbs) torque input to each side of the transmission. During tests, two input pinions were slow rolled while in mesh with the two face gears. Two idler gears were also used in the configuration to recombine torque near the output. Resistance was applied at the output face gear to create the required loading conditions in the gear teeth. A system of weights, pulleys and cables were used in the test rig to provide both the input and output loading. Strain gages applied in the tooth root fillets provided strain indication used to determine torque splitting conditions at the input pinions. The final two pinion-two idler tests indicated 52% to 48% average torque split capabilities for the two pinions. During the same tests, a 57% to 43% average distribution of the torque being recombined to the upper face gear from the lower face gear was measured between the two idlers. The POC split torque tests demonstrated that face gears can be applied effectively in split torque rotorcraft transmissions, yielding good potential for significant weight, cost and reliability improvements over existing equipment using spiral bevel gearing.

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

2002-01-01

354

Economic analysis of robotic torque measurement system  

SciTech Connect

A cleanroom robot is being used to measure the torque characteristic of rotary solenoids, replacing a manual measurement procedure. The system can test two different part numbers and can distinguish between these parts without operator assistance. To make the system more cost-effective, several tests have been added to sequence. Bearing drag and coil resistance are measured, and the change in resistance due to coil heating is monitored. The insulation resistance between coil and housing is measured at 250 volts. The bar-coded serial number of each unit is read by passing the housing over a bar code wand. All information is used to generate a report for each unit tested, showing part number, serial number, measured data, and pass-fail notification. The system saves 0.114 standard hours per part compared to manual testing and generates a return on investment of over 20 percent. 2 refs., 4 figs.

Lembke, J.R.

1991-07-01

355

Spin transfer torque in ferroelectric tunnel junctions  

NASA Astrophysics Data System (ADS)

The worldwide interest for spintronics grows up every year, magnetic oscillators and resistance switchers became an important part of electronics with promising applications such as tunable microwave radiation, magnetic memory cells, magnetic field sensors, etc. A non-equilibrium spin-dependent transport in magnetic tunnel junctions comprising a ferroelectric barrier was studied. The exact solutions of the free electron Schr"odinger equation for electron tunneling in the presence of interfacial screening are obtained by Bessel and Airy functions. As a result, bias-dependence of the tunneling magneto- and electro-resistance are obtained. The barrier asymmetry induced by the ferroelectric polarization produces strong modifications compared to regular tunnel junctions in the bias-dependence of the transport properties. Furthermore, manipulating the electric polarity of the barrier provides a way to control the magnitude and sign of the spin transfer torque.

Useinov, Arthur; Manchon, Aurelien

2013-03-01

356

Alternating bending-steady torque fatigue reliability  

NASA Technical Reports Server (NTRS)

Results generated by three unique fatigue reliability research machines which can apply alternating-bending loads combined with steady torque are presented. Six-inch long, AISI steel, grooved specimens with a stress concentration factor of 1.42 and Rockwell C 35/40 hardness were subjected to various combinations of these loads and cycled to failure. The generated cycles-to-failure and staircase-testing data are statistically analyzed to develop distributional S-N and Goodman diagrams. Various failure theories are investigated to determine which one best represents the data. The effect of the groove and of the various combined bending-torsion loads on the finite and endurance life strength of such components, as well as on the Goodman diagram, are determined. Design applications are presented.

Kececioglu, D.; Chester, L. B.; Dodge, T. M.

1974-01-01

357

Functional torque ratios and torque curve analysis of shoulder rotations in overhead athletes with and without impingement symptoms.  

PubMed

In this study, we evaluated the peak torque, functional torque ratios, and torque curve profile of the shoulder rotators in overhead athletes with impingement symptoms so as to examine possible alterations in response to sports training and shoulder pain. Twenty-one overhead athletes with impingement symptoms were compared with 25 overhead athletes and 21 non-athletes, none of whom were symptomatic for impingement. The participants performed five maximal isokinetic concentric and eccentric contractions of medial and lateral shoulder rotations at 1.57 rad · s(-1) and 3.14 rad · s(-1). Isokinetic peak torque was used to calculate the eccentric lateral rotation-to-concentric medial rotation and the eccentric medial rotation-to-concentric lateral rotation ratios. An analysis of the torque curve profiles was also carried out. The eccentric lateral rotation-to-concentric medial rotation torque ratio of asymptomatic athletes was lower than that of non-athletes at both test velocities. The concentric medial rotation isokinetic peak torque of the asymptomatic athletes, at 3.14 rad · s(-1), was greater than that of the non-athletes, and the peak appeared to occur earlier in the movement for athletes than non-athletes. These findings suggest that there may be adaptations to shoulder function in response to throwing practice. The eccentric medial rotation-to-concentric lateral rotation torque ratio was altered neither by the practice of university-level overhead sports nor impingement symptoms. PMID:22092229

Zanca, Gisele G; Oliveira, Ana B; Saccol, Michele F; Ejnisman, Benno; Mattiello-Rosa, Stela M

2011-12-01

358

Report on Toyota\\/Prius Motor Torque-Capability, Torque-Property, No-Load Back EMF, and Mechanical Losses  

Microsoft Academic Search

In today's hybrid vehicle market, the Toyota Prius drive system is currently considered the leader in electrical, mechanical, and manufacturing innovations. It is significant that in today's marketplace, Toyota is able to manufacture and sell the vehicle for a profit. This project's objective is to test the torque capability of the 2004 Prius motor and to analyze the torque properties

J. S. Hsu; D. C. W. Ayers; C. L. Coomer; R. H. Wiles

2004-01-01

359

The control of stator flux and torque in the surface permanent magnet synchronous motor direct torque control system  

Microsoft Academic Search

This paper discusses the control of stator flux and torque in the surface permanent magnet synchronous motor (SPMSM) direct torque control (DTC) system. The study shows the angle between stator flux vector and the applying voltage vector determines the dynamic behavior of stator flux and the angle between rotor flux vector and the applying voltage vector determines the dynamic behavior

Yaohua Li; Weiguo Liu; Zhaoyang Fu; Dieter Gerling

2009-01-01

360

Gender-specific knee extensor torque, flexor torque, and muscle fatigue responses during maximal effort contractions  

Microsoft Academic Search

.   The purpose of this study was to examine gender differences in knee extensor and flexor peak torque, work, power, and muscle\\u000a fatigue during maximal effort isokinetic contractions. Subjects included 19 healthy male and 20 healthy female volunteers.\\u000a Following a dynamic warm-up period, subjects performed 30 reciprocal, concentric maximal knee extension and flexion contractions\\u000a at a pre-set angular velocity of

Danny M. Pincivero; Claudio B. Gandaio; Yoshihiko Ito

2003-01-01

361

Improvement of Torque Response and Examination of Sensorless Drive System Based on Direct Torque Control for IPMSM  

NASA Astrophysics Data System (ADS)

This paper examines the sensorless control system based on the direct torque control (DTC) for an interior permanent magnet synchronous motor (IPMSM). In the DTC system, the rotor position is not required, and the rotor speed is estimated from the estimated position of stator flux-linkage vector. In addition, the maximum torque per ampere (MTPA) control and the flux weakening (FW) control can be applied to the DTC as well as the current control method in the d-q reference frame. Therefore the DTC can operate over a wide speed range. The characteristic of the maximum power operation is shown by the experimental result. The torque response is investigated by the simulation and experimental results. A relationship between the controller gain and torque response is shown, and an improvement method of the torque response is proposed.

Inoue, Yukinori; Morimoto, Shigeo; Sanada, Masayuki

362

In situ production of ethane and propane in dust-rich Greenland ice core samples: is methane also affected?  

NASA Astrophysics Data System (ADS)

The analysis of methane and the stable isotopic composition extracted from ice core samples provides a suite of valuable climatic sensitive parameters like CH4 mixing ratios, d13C(CH4), dD(CH4) and the respective interhemispheric differences of these parameters. Their interpretation as palaeoclimatic proxies relies on the assumption that the measured properties represent true atmospheric concentrations after correction for the well-known diffusive processes in the firn column. Up to now, methane is assumed to be unaffected from in situ production with the exception of melt layers and alpine ice cores which show elevated concentrations. In contrast, other trace gases like CO2 and N2O show in situ production under certain conditions, especially in dust-rich Greenland ice core samples. Also other trace gases which are chemically more related to methane, like the hydrocarbons ethane and propane as well as methyl chloride show pronounced in situ production in some ice cores. To explore the processes leading to situ production for ethane and propane and a possible link to methane it is helpful to measure these parameters simultaneously on a single ice core sample. For this task we present a new online preparation line for extraction and measurement of several trace gas species (isotope ratios and/or mixing ratios) of 150-200 g ice samples. The analytical setup comprises continuous flow-isotope ratio mass spectrometry and a custom-built online pre-concentration system with a vacuum extraction part and a continuous He flow GC line. Our setup allows for analysing isotope ratios of CH4(13C) and N2O (d15N, d18O) as well as their mixing ratios and, additionally, the mixing ratios of ethane, propane and methyl chloride. We measured ice core samples on the NGRIP ice core during, selected time intervals covering DO events, the LGM and, the Bølling/Allerød Younger Dryas. Where possible, we focused on intervals where dust showed its larges variability. In summary, we see a strong in situ production for ethane, propane and methyl chloride related to dust concentrations in Greenland ice. However, methane is likely not affected by this production pathway or the contribution is so small that it is hidden in the atmospheric signal so far. A better sampling strategy focusing with a denser temporal coverage on intervals with variable dust loading could further constrain a possible contribution of methane from in situ production.

Schmitt, J.; Seth, B.; Fischer, H.

2012-04-01

363

USAF Civil Engineering Work Force Productivity: An Analysis of Non-Behavioral Factors Affecting Planning Technician Labor Manhour Estimates for In-House Work Requirements.  

National Technical Information Service (NTIS)

The authors investigated how work requirement manhour estimates affect Air Force Civil Engineering productivity ratios by gathering standard and adusted estimates for five hypothetical work requirements and selected planner and work center data from a sam...

W. F. Hanley F. C. Smith

1976-01-01

364

40 CFR Table 9 to Subpart Xxxx of... - Minimum Data for Continuous Compliance With the Emission Limits for Tire Production Affected Sources  

Code of Federal Regulations, 2010 CFR

...Production Affected Sources 9 Table 9 to Subpart XXXX of Part 63 Protection of Environment ENVIRONMENTAL...Rubber Tire Manufacturing Pt. 63, Subpt. XXXX, Table 9 Table 9 to Subpart XXXX of Part 63âMinimum Data for Continuous...

2009-07-01

365

Detection of genetic association and functional polymorphisms of UGDH affecting milk production trait in Chinese Holstein cattle  

PubMed Central

Background We previously localized a quantitative trait locus (QTL) on bovine chromosome 6 affecting milk production traits to a 1.5-Mb region between BMS483 and MNB-209 via genome scanning followed by fine mapping. Results Totally 15 genes were mapped within such linkage region through bioinformatic analysis of the cattle-human comparative map and bovine genome assembly. Of them, the UDP-glucose dehydrogenase (UGDH) was suggested as a potential positional candidate gene for milk production traits based on its corresponding physiological and biochemical functions and genetic effects. By sequencing all the coding exons and the untranslated regions in UGDH with pooled DNA of 8 sires represented the separated families detected in our previous studies, a total of ten SNPs were identified and genotyped in 1417 Holstein cows of 8 separation families. Individual SNP-based association analysis revealed 4 significant associations of SNP Ex1-1, SNP Int3-1, SNP Int5-1, and SNP Ex12-3 with milk yield (P < 0.05), and 2 significant associations of SNP Ex1-1 and SNP Ex12-3 with protein yield (P < 0.05). Furthermore, our haplotype-based association analyses indicated that haplotypes G-C-C, formed by SNP Ex12-2-SNP Int11-1-SNP Ex11-1, T-G, formed by SNP Int9-3-SNP Int9-2, and C-C, formed by SNP Int5-1-SNP Int3-1, are significantly associated with protein percentage (F=4.15; P=0.0418) and fat percentage (F=5.18~7.25; P=0.0072~0.0231). Finally, by using an in vitro expression assay, we demonstrated that the A allele of SNP Ex1-1 and T allele of SNP Ex11-1of UGDH significantly decreases the expression of UGDH by 68.0% at the RNA, and 50.1% at the protein level, suggesting that SNP Ex1-1 and Ex11-1 represent two functional polymorphisms affecting expression of UGDH and may partly contributed to the observed association of the gene with milk production traits in our samples. Conclusions Taken together, our findings strongly indicate that UGDH gene could be involved in genetic variation underlying the QTL for milk production traits.

2012-01-01

366

Cocoa products decrease low density lipoprotein oxidative susceptibility but do not affect biomarkers of inflammation in humans.  

PubMed

Flavonoids and related polyphenolics with antioxidant and anti-inflammatory activities may play a role in the prevention of cardiovascular disease by decreasing oxidative stress and inflammation. We wished to determine the effects of cocoa extract supplementation on markers of oxidative stress and inflammation. Healthy subjects (n = 25) were studied at baseline, after cocoa supplementation (36.9 g of dark chocolate bar and 30.95 g of cocoa powder drink) for 6 wk and after a 6-wk washout period. Fasting blood and early morning urine were collected at the three time points. Two indices of flavonoid intake, total phenols and oxygen radical absorbance capacity of plasma, were measured after an overnight fast. Neither was affected by supplementation. Measures of oxidative stress included copper-catalyzed LDL oxidation kinetics and urinary F(2) isoprostanes. LDL oxidizability was lower after chocolate supplementation as evidenced by a longer lag time (P < 0.05) of conjugated diene formation (101.0 +/- 20.7 min) compared with baseline (91.3 +/- 18.0 min) and washout (96.4 +/- 7.5 min) phases. There was no effect of chocolate on urinary F(2) isoprostane levels or on markers of inflammation including the whole-blood cytokines, interleukin-1 beta, interleukin-6 and tumor necrosis factor-alpha, high sensitivity C-reactive protein and P-selectin. In conclusion, cocoa products supplementation in humans affects LDL oxidizability, but not urinary F(2) isoprostanes or markers of inflammation. PMID:12468604

Mathur, Surekha; Devaraj, Sridevi; Grundy, Scott M; Jialal, Ishwarlal

2002-12-01

367

Lunar and Solar Torques on the Oceanic Tides  

NASA Technical Reports Server (NTRS)

Brosche and Seiler recently suggested that direct lunar and solar tidal torques on the oceanic tides play a significant role in the earth's short-period angular momentum balance ("short-period" here meaning daily and sub-daily). We reexamine that suggestion here, concentrating on axial torques and hence on variations in rotation rate. Only those spherical harmonic components of the ocean tide having the same degree and order as the tidal potential induce nonzero torques. Prograde components (those moving in the same direction as the tide-generating body) produce the familiar secular braking of the earth's rotation. Retrograde components, however, produce rapid variations in UTI at twice the tidal frequency. There also exist interaction torques between tidal constituents, e.g. solar torques on lunar tides. They generate UTI variations at frequencies equal to the sums and differences of the original tidal frequencies. We give estimates of the torques and angular momentum variations for each of the important regimes, secular to quarter-diurnal. For the M(sub 2) potential acting on the M(sub 2) ocean tide, we find an associated angular momentum variation of amplitude 3 x 10(exp 19) N m. This is 5 to 6 orders of magnitude smaller than the angular momentum variations associated with tidal currents. We conclude that these torques do not play a significant role in the short-period angular momentum balance.

Ray, Richard D.; Bills, Bruce G.; Chao, Benjamin F.

1998-01-01

368

Improved extraction torque of hydroxyapatite-coated pedicle screws.  

PubMed

Loosening of the screws is a problem in instrumentation with pedicle screws. Coating with hydroxyapatite improves the holding characteristics for metal implants, but the possible effects on the anchorage of pedicle screws have not been described. In this study, seven patients were operated on with spinal instrumentation using four stainless steel pedicle screws. Hydroxyapatite-coated screws were used in either the upper or the lower of the instrumented levels. The insertion torque was measured. In four cases the screws were removed after 10-22 months and the extraction torque was measured. The mean insertion torque was found to be significantly greater in the hydroxyapatite-coated screws (107 Ncm) than in the standard screws (76 Ncm). In three cases, the extraction torque for the hydroxyapatite-coated screws exceeded the range for the torque wrench (600 Ncm), while the conventional screws were loose (< 5 Ncm). In one case, the extraction torque was 475 and 550 Ncm for the coated screws, and 5 and 25 Ncm for the conventional screws. The difference in extraction torque was significant. Hydroxyapatite coating was shown to have improved the purchase of pedicle screws very effectively. By using fully coated screws, as in the present study, extraction was extremely difficult compared to extraction of conventional stainless steel screws, which were regularly loose. By reducing the area of the screws that is coated, it may be possible to achieve an enhanced purchase while extraction will be easier when compared to fully coated screws. PMID:11189923

Sandén, B; Olerud, C; Johansson, C; Larsson, S

2000-12-01

369

Current-induced torques and interfacial spin-orbit coupling  

NASA Astrophysics Data System (ADS)

In bilayer systems consisting of an ultrathin ferromagnetic layer adjacent to a metal with strong spin-orbit coupling, an applied in-plane current induces torques on the magnetization. The torques that arise from spin-orbit coupling are of particular interest. Here we use first-principles methods to calculate the current-induced torque in a Pt-Co bilayer to help determine the underlying mechanism. We focus exclusively on the analog to the Rashba torque, and do not consider the spin Hall effect. The details of the torque depend strongly on the layer thicknesses and the interface structure, providing an explanation for the wide variation in results found by different groups. The torque depends on the magnetization direction in a way similar to that found for a simple Rashba model. Artificially turning off the exchange spin splitting and separately the spin-orbit coupling potential in the Pt shows that the primary source of the "fieldlike" torque is a proximate spin-orbit effect on the Co layer induced by the strong spin-orbit coupling in the Pt.

Haney, Paul M.; Lee, Hyun-Woo; Lee, Kyung-Jin; Manchon, Aurélien; Stiles, M. D.

2013-12-01

370

Factors affecting the formation of disinfection by-products during chlorination and chloramination of secondary effluent for the production of high quality recycled water.  

PubMed

During the production of high quality recycled water by reverse osmosis membrane filtration secondary effluent must be disinfected to limit biofouling on the membrane surface. Advanced Water Treatment Plants in South East Queensland, Australia use disinfectant contact times ranging from 30 min up to 24 h. Disinfectants such as chlorine and chloramines react with effluent organic matter to generate disinfection by-products (DBPs) which could be potentially hazardous to human health if the water is destined for supplementing public water supplies. In this context, secondary effluents are of concern because of their high total organic carbon content which can act as DBP precursors. Also, effluent organic matter may form different DBPs to those formed from natural organic matter during conventional drinking water treatment, either in quantity, identity or simply in the abundance of different DBPs relative to each other. It cannot be assumed per se with certainty that DBP formation will be affected in the same way by operational changes as in drinking water production. Response surface modelling has been employed in this study at the bench scale to investigate the effect of reaction time (0-24 h), pH (5.5-8.5), temperature (23-35 °C), disinfection strategy (chlorine vs chloramines used prior to membrane treatment) and the interaction between these different parameters on DBP formation during disinfection of secondary effluent. The concentration of halogenated DBPs formed during the first 24 h of reaction with the different disinfectants followed the order chlorination > in line-formed monochloramine > pre-formed monochloramine. Contact time with chlorine was the major influencing factor on DBP formation during chlorination, except for the bromine-containing trihalomethanes and dibromoacetonitrile for which pH was more significant. Chlorination at high pH led to an increased formation of chloral hydrate, trichloronitromethane, dibromoacetonitrile and the four trihalomethanes while the opposite effect was observed for the other targeted DBPs. Temperature was identified as the least influencing parameter compared to pH and reaction time for all DBPs in all the disinfection strategies, except for the formation of chloral hydrate where pH and temperature had a similar significance and bromoform that was similarly affected by temperature and reaction time. Chloramines employed at pH 8.5 reduced the concentration of all studied DBPs compared to pH 5.5. Furthermore, reaction time was the most significant factor for trichloronitromethane, chloroform, trichloroacetonitrile, dichloroacetonitrile and bromochloroacetonitrile formation while pH was the most influencing factor affecting the formation of the remaining DBPs. PMID:24095593

Doederer, Katrin; Gernjak, Wolfgang; Weinberg, Howard S; Farré, Maria José

2014-01-01

371

Torque and Rotational Speed Estimation with Parameter Identification of Line-Start Induction Motor for Motor-Operated Valves  

NASA Astrophysics Data System (ADS)

This paper presents a method for estimating the torque and rotational speed of line-start induction motors for motor-operated valves. Routine inspections of the valves are carried out because motor-operated valves are used in momentous plants such as power plants where securing, the reliability of the valves are very important. Movement environments in these plants are characterized by high temperature and humidity and therefore, it is difficult to position sensors near motors. In such a case, we must troubleshoot the system without using torque or speed sensors. The proposed method can estimate the torque and speed of an induction motor by using currents and voltages near the switchboard. Furthermore, we propose the parameter identification of mutual inductance by comparing the scalar and vector products between currents and voltages. The proposed method is validated by experimental results.

Takahashi, Akiko; Oguro, Ryuichi; Hanamoto, Tsuyoshi; Tanaka, Koji; Nagaiwa, Keiichiro

372

High torque DC motor fabrication and test program  

NASA Technical Reports Server (NTRS)

The testing of a standard iron and standard alnico permanent magnet two-phase, brushless dc spin motor for potential application to the space telescope has been concluded. The purpose of this study was to determine spin motor power losses, magnetic drag, efficiency and torque speed characteristics of a high torque dc motor. The motor was designed and built to fit an existing reaction wheel as a test vehicle and to use existing brass-board commutation and torque command electronics. The results of the tests are included in this report.

Makus, P.

1976-01-01

373

Surface modification of clutch plates to reduce disengaged drag torque  

NASA Astrophysics Data System (ADS)

Viscous drag torque in disengaged clutches is a significant source of power loss in modern transportation. The main way to reduce this drag torque is to introduce air between the plates when disengaged without reducing the transmission fluid flow eventually needed for reengagement. Six different groove patterns are tested experimentally to determine which have the lowest drag characteristics. Our computations using Fluent showed that the contact angle made by oil with the stationary plate is critical in determining aeration initiation. Experiments coating the stationary plate with an oleophobic substance like Teflon, confirmed these simulations. We will show torque comparisons and visualization through a quartz disk acting as one of the clutch plates.

Aphale, Chinar R.

2005-11-01

374

Antenna axis drive torques for the 70-meter antenna  

NASA Technical Reports Server (NTRS)

Antenna axis speeds versus wind speeds are given in terms of dish size, hydraulic motor size, and the number of servo valves. An increase in the dish diameter of antenna is usually accompanied by increases in the axis torques required to drive the antenna against wind. The proposed increase in the diameters of the 64-m antenna dishes to 70 m (plus a noise shield) does require increased axis torques. The increased dish diameter causes the maximum azimuth and elevation torques to increase 48% and 43% respectively.

Mcginness, H. D.

1985-01-01

375

How do weather extremes affect rice productivity in a changing climate? An answer to episodic lack of sunshine.  

PubMed

Here, we experimentally examined how an episodic lack of sunshine (ELS), as an extreme weather event, would affect rice productivity under warming with elevated [CO2 ]. In 2009 and 2010, rice plants were grown at two levels of [CO2 ] (ca. 390 and 650 ?l l(-1) ) and three levels of warming (?ambient, +1.2 °C, and +2.2/2.4 °C) in six independent temperature gradient field chambers (three each for ambient and elevated [CO2 ]). At panicle initiation (PI), booting (BT), or flowering (FL), rice plants were exposed to ELS (ca. 18% of full sunlight) for 10-14 days consecutively. As expected, ELS elicited a significant reduction in aboveground biomass (AGB) and yields. However, elevated [CO2 ] had the potential to relieve the ELS-induced reduction in AGB and yield, whereas warming had the reverse effect for yields, without a significant warming × [CO2 ] interaction. When ELS applied at PI, BT, and FL, the extents to which warming-reduced yields (averaged across [CO2 ] levels) ranged from 9 to 25%, 7 to 14, and 10 to 18% at +1.2 °C, and ranged from 24 to 56%, 22 to 55%, and 18 to 46% at +2.2/2.4 °C across two seasons, respectively. Meanwhile, under normal sunshine they ranged from 1 to 3% at +1.2 °C and 7 to 21% at +2.2/2.4 °C. Warming predisposed rice plants that had experienced ELS to be more sensitive to spikelet sterility and spikelet number per panicle, accounting for most of the yield reductions. These findings provide evidence that an expected warming could further exacerbate rice productivity if ELS occurs simultaneously during reproductive stages. Our results collectively suggest that it might be critically important to consider extreme events for a holistic evaluation of the potential impact of warming and [CO2 ] on crop productivity, when considering changing climate. PMID:23504904

Choi, Woo-Jung; Lee, Myoung-Seok; Choi, Jae-Eul; Yoon, Sanghoo; Kim, Han-Yong

2013-04-01

376

Highly sensitive nanoscale spin-torque diode.  

PubMed

Highly sensitive microwave devices that are operational at room temperature are important for high-speed multiplex telecommunications. Quantum devices such as superconducting bolometers possess high performance but work only at low temperature. On the other hand, semiconductor devices, although enabling high-speed operation at room temperature, have poor signal-to-noise ratios. In this regard, the demonstration of a diode based on spin-torque-induced ferromagnetic resonance between nanomagnets represented a promising development, even though the rectification output was too small for applications (1.4?mV?mW(-1)). Here we show that by applying d.c. bias currents to nanomagnets while precisely controlling their magnetization-potential profiles, a much greater radiofrequency detection sensitivity of 12,000?mV?mW(-1) is achievable at room temperature, exceeding that of semiconductor diode detectors (3,800?mV?mW(-1)). Theoretical analysis reveals essential roles for nonlinear ferromagnetic resonance, which enhances the signal-to-noise ratio even at room temperature as the size of the magnets decreases. PMID:24141450

Miwa, S; Ishibashi, S; Tomita, H; Nozaki, T; Tamura, E; Ando, K; Mizuochi, N; Saruya, T; Kubota, H; Yakushiji, K; Taniguchi, T; Imamura, H; Fukushima, A; Yuasa, S; Suzuki, Y

2014-01-01

377

Spin transfer torque switching of Co nanoparticles  

NASA Astrophysics Data System (ADS)

Spin transfer torque effect has potential application in Magnetic Random Access Memory (MRAM) devices as a way to address the memory elements. Most spin transfer studies are based on patterned multilayer thin films with 100 nm lateral dimension. In this work, we demonstrate the feasibility of the spin transfer switching of a few cobalt nanoparticles with a diameter of < 5 nm at 4.2 K. The motivation arises from the prospect of device miniaturization and the capability to manipulate an individual magnetic nanoparticle. We use a multilayer thin film Cu(100nm)/Co(10nm)/Cu(3nm)/Co(0.5nm)/Au(2nm). The 0.5 nm Co layer is not continuous, and it consists of isolated Co particles formed due to surface tension. A mechanical point contact is formed on the multilayer film at 4.2K. By varying the size of the contact, the number of nanoparticles underneath a point contact can be controlled between ˜5 and ˜50. Hysteretic loops in dV/dI -- I measurements clearly indicates spin-transfer switching. The dV/dI-I curves are qualitatively different between point contacts involving only few particles (5-10) and those involving many particles (40-50).

Zou, Han; Wang, Xiaojun; Ji, Yi

2009-03-01

378

Highly sensitive nanoscale spin-torque diode  

NASA Astrophysics Data System (ADS)

Highly sensitive microwave devices that are operational at room temperature are important for high-speed multiplex telecommunications. Quantum devices such as superconducting bolometers possess high performance but work only at low temperature. On the other hand, semiconductor devices, although enabling high-speed operation at room temperature, have poor signal-to-noise ratios. In this regard, the demonstration of a diode based on spin-torque-induced ferromagnetic resonance between nanomagnets represented a promising development, even though the rectification output was too small for applications (1.4?mV?mW-1). Here we show that by applying d.c. bias currents to nanomagnets while precisely controlling their magnetization-potential profiles, a much greater radiofrequency detection sensitivity of 12,000?mV?mW-1 is achievable at room temperature, exceeding that of semiconductor diode detectors (3,800?mV?mW-1). Theoretical analysis reveals essential roles for nonlinear ferromagnetic resonance, which enhances the signal-to-noise ratio even at room temperature as the size of the magnets decreases.

Miwa, S.; Ishibashi, S.; Tomita, H.; Nozaki, T.; Tamura, E.; Ando, K.; Mizuochi, N.; Saruya, T.; Kubota, H.; Yakushiji, K.; Taniguchi, T.; Imamura, H.; Fukushima, A.; Yuasa, S.; Suzuki, Y.

2014-01-01

379

Reliability of Cybex II isokinetic evaluations of torque in post-poliomyelitis syndrome.  

PubMed

The aim of this study was to ascertain the reliability of isokinetic strength measurements in a population of post-poliomyelitis subjects (PPS). Eight subjects (four males and females, mean age of 47.5 +/- 10 and 56.8 +/- 16 years, respectively) were evaluated, on a weekly basis for three weeks at approximately the same time of day. During each test session the knee flexors and extensors (bilaterally, where possible) were evaluated. Subjects became familiar with the equipment prior to recording three maximal contractions at the four test velocities (1.05, 2.09, 3.14, 4.18rads.s-1). A two-minute rest period was allowed between sets of contractions. The variables of peak torque, angle of peak torque, torque at specific joint angles (0.79 and 1.05rads), total contractile work, maximum power, and average power were measured on-line with the Cybex II a system using a commercially available software package. In both muscle groups, all the variables were significantly weaker on the most affected, but testable limb (p < 0.01) in subjects where both limbs could be tested (n = 5). Peak torque and total work of the quadriceps were observed to decrease with increasing velocity of movement. The effects of velocity were less apparent in the hamstrings. Average and maximum power developed by the knee extensors and flexors increased with increasing velocity of movement. Reliability of performance over three test sessions was confirmed by the intraclass correlation coefficient (ICC) values derived from the univariate ANOVAs calculated for each of the above variables (> 0.80).(ABSTRACT TRUNCATED AT 250 WORDS) PMID:8328895

Kilfoil, M R; St Pierre, D M

1993-07-01

380

East meets West: Differing views of the Aleutian Low's role in affecting Holocene productivity in the Subarctic North Pacific Ocean  

NASA Astrophysics Data System (ADS)

Modern instrumental and monitoring observations indicate strong multi-decadal changes and spatial heterogeneities affect climate and marine ecosystems in the North Pacific Ocean. Networks of high-resolution paleoclimate archives from this dynamic region are therefore required to describe changes prior to historical records. We present new decadally-resolved marine sediment core data from the Kuril Islands in the Sea of Okhotsk, together with sub-decadal data from the temperate fjords of the Gulf of Alaska (GoAK). These distant sites are located along the western (Kuril) and eastern (GoAK) boundaries of the Subarctic North Pacific Ocean, where micronutrient-rich coastal waters interact with North Pacific high-nutrient-low-chlorophyll (HNLC) waters to drive highly productive marine ecosystems. In the Sea of Okhotsk, a notable increase in opal concentrations (a proxy for past siliceous primary productivity) occurs during the middle Holocene between ~5000 and 6000 yrs ago, while alkenone-based warm season SST proxies either decline or remain relatively constant. A similar middle Holocene increase in opal concentrations is also observed in the GoAK during an interval of declining warm season coastal SAT as inferred from pollen transfer functions [Heusser et al., 1985]. Declining summer solar insolation during the middle Holocene can explain the overall decline in warm-season SST in both the Sea of Okhotsk and the Gulf of Alaska. However, as the increase in opal likely reflects an improvement in North Pacific phytoplankton growing conditions during the spring/summer bloom season, then the opal increase seems unlikely to be related directly to summer solar insolation. We propose a middle Holocene intensification of the Aleutian Low (AL) pressure cell and concomitant changes in North Pacific circulation may be responsible. In both regions, several potential mechanisms related to an intensified AL could result in greater productivity including: (i) increased advection fluxes of HNLC macronutrients into coastal areas; (ii) greater winter vertical mixing due to elevated storm activity; and (iii) enhanced coastal euphotic zone stratification from increased precipitation and fluvial discharge. Long-term changes in sea-ice distribution in the Sea of Okhotsk may also influence productivity locally, though this relationship is complicated by interactions between the Siberian High and the AL, as well as Amur River freshwater discharge.

Addison, J. A.; Finney, B. P.; Harada, N.

2012-12-01

381

Estimation of Coriolis Force and Torque Acting on Ares-1  

NASA Technical Reports Server (NTRS)

A document describes work on the origin of Coriolis force and estimating Coriolis force and torque applied to the Ares-1 vehicle during its ascent, based on an internal ballistics model for a multi-segmented solid rocket booster (SRB).

Mackey, Ryan M.; Kulikov, Igor K.; Smelyanskiy, Vadim; Luchinsky, Dmitry; Orr, Jeb

2011-01-01

382

Constant torque in flagellar bacterial motors optimizes space exploration  

NASA Astrophysics Data System (ADS)

Experiments indicate that the torque provided by the bacterial rotary motor is approximately constant over a large range of angular speeds. Constant torque implies that the power spent in active motion is proportional to the instantaneous bacterial speed, if the relation between angular speed and swimming speed is linear. Here we show that a constant torque maximizes the volume of the region explored by a bacterium in a resource-depleted medium. Given that nutrients in the ocean are often concentrated in separate, ephemeral patches, we propose that the observed constancy of the torque may be a trait evolved to maximize bacterial survival in the ocean. We also discuss the dependence of the explored volume with the particular features of the bacterial propulsion mechanism.

Condat, Carlos A.; di Salvo, Mario E.

2012-02-01

383

Control of noise in magnetic multilayers by spin torque  

NASA Astrophysics Data System (ADS)

In this work we show that the stability of magnetic nanostructures can be enhanced by time-dependent spin momentum transfer. Building reliable magnetic devices at smaller scales need to address the issue of thermal noise. Using two commonly studied magnetic systems with multiple stable states at zero temperature as examples, we show that periodic spin torques can enhance the stability of the system and hence suppress the noise due to interwell transitions. In the case of weak periodic spin torques, stochastic resonance which is usually associated with ac magnetic fields is also manifested for non-conservative torques. In more complex systems with a relatively low energy barrier, it is shown that high frequency spin torques can inhibit interwell transitions and in effect suppress the telegraph noise due to the switching between neigboring states.

Rebei, Adnan

2012-02-01

384

Torque Splitting by a Concentric Face Gear Transmission.  

National Technical Information Service (NTIS)

Tests of a 167 Kilowatt (224 Horsepower) split torque face gearbox were performed by the Boeing Company in Mesa, Arizona, while working under a Defense Advanced Research Projects Agency (DARPA) Technology Reinvestment Program (TRP). This paper provides a ...

R. R. Filler G. F. Heath S. C. Slaughter D. G. Lewicki

2002-01-01

385

14 CFR 23.397 - Limit control forces and -torques.  

Code of Federal Regulations, 2011 CFR

...2014-01-01 false Limit control forces and -torques...AND COMMUTER CATEGORY AIRPLANES Structure Control Surface and System...for commuter category airplanes, the specified values...any individual set of control systems or...

2014-01-01

386

Cogging torque reduction of flux-switching permanent magnet machines without skewing  

Microsoft Academic Search

The flux-switching permanent magnet (FSPM) machine exhibits competitive torque capability and power density due to the high flux density. As a penalty, the cogging torque is relative large, resulting in unfavorable torque pulsation. Due to the simple and robust rotor construction, additional dummy slots are adopted to reduce the cogging torque without skewing magnets or teeth. The optimal dimensions of

Wei Hua; Ming Cheng

2008-01-01

387

3-D magnetic field analysis of hydraulic servo valve torque motor with magnetic fluid  

Microsoft Academic Search

As a functional material, magnetic fluid (MF) is filled in the working clearances of torque motor in hydraulic servo valve. The construction and working principle of torque motor with magnetic fluid are introduced. Using 3-D magnetic field finite element analysis (FEA) method, the magnetic field distribution and characteristics of torque created by the torque motor are analyzed. Calculation results are

Li Songjing; Jiang Dan; Xu Benzhou; Sheng Xiaowei

2005-01-01

388

Cogging Torque in Flux-Switching Permanent Magnet Machines  

Microsoft Academic Search

The influence of manufacturing tolerances on the cogging torque waveforms, as well as the back-EMF waveforms, in 3- and 5-phase flux-switching permanent magnet (FSPM) machines having different numbers of stator\\/rotor poles is investigated by finite element analyses and experiments. The cause of excessive cogging torque in the prototype FSPM machines has been identified. It is due to modular stator structure

Z. Q. Zhu; A. S. Thomas; J. T. Chen; G. W. Jewell

2009-01-01

389

Intelligent built-in torque sensor for harmonic drive systems  

Microsoft Academic Search

A harmonic drive is a compact, light-weight and high-ratio torque transmission device which is used in many electrically actuated robot manipulators. In this paper a built-in torque sensor for harmonic drive systems is examined in detail. The method proposed by Hashimoto (1989), in which strain-gauges are directly mounted on the flexspline, is employed and improved. To minimize sensing inaccuracy, four

H. D. Taghirad; A. Helmy; P. R. Belanger

1997-01-01

390

Robust design for torque optimization using response surface methodology  

Microsoft Academic Search

This paper discusses response surface methodology (RSM) as an efficient approach to parametric model building and design optimization. Application of RSM is presented for torque optimization in spindle motor design. A window-zoom-in method is studied to improve the optimization procedure. Finite-element analysis and RSM using mixed resolution central composite design are utilized to determine the optimum torque performance. Analysis of

X. K. Gao; T. S. Low; Z. J. Liu; S. X. Chen

2002-01-01

391

Pressure gradient torque in highly supersonic nonaxisymmetric accretion  

NASA Technical Reports Server (NTRS)

The contribution of a pressure gradient torque to the angular momentum transfer rate in highly supersonic nonaxisymmetric accretion flows is considered. This study takes into account the contribution due to the pressure variation in the postaccretion-shock region which is significant for high Mach number accretion. For the case of accretion flow with Mach (infinity) of not less than 5, the overall accretion torque is shown to approach a constant value.

Ho, Cheng; Taam, Ronald E.; Fryxell, Bruce A.; Matsuda, Takuya; Koide, Hiroshi

1989-01-01

392

Direct shaft torque measurements in a transient turbine facility  

NASA Astrophysics Data System (ADS)

This paper describes the development and implementation of a shaft torque measurement system for the Oxford Turbine Research Facility (formerly the Turbine Test Facility (TTF) at QinetiQ, Farnborough), or OTRF. As part of the recent EU TATEF II programme, the facility was upgraded to allow turbine efficiency measurements to be performed. A shaft torque measurement system was developed as part of this upgrade. The system is unique in that, to the authors' knowledge, it provided the first direct measurement of shaft torque in a transient turbine facility although the system has wider applicability to rotating test facilities in which power measurement is a requirement. The adopted approach removes the requirement to quantify bearing friction, which can be difficult to accurately calibrate under representative operating conditions. The OTRF is a short duration (approximately 0.4 s run time) isentropic light-piston facility capable of matching all of the non-dimensional parameters important for aerodynamic and heat studies, namely Mach number, Reynolds number, non-dimensional speed, stage pressure ratio and gas-to-wall temperature ratio. The single-stage MT1 turbine used for this study is a highly loaded unshrouded design, and as such is relevant to modern military, or future civil aero-engine design. Shaft torque was measured directly using a custom-built strain gauge-based torque measurement system in the rotating frame of reference. This paper describes the development of this measurement system. The system was calibrated, including the effects of temperature, to a traceable primary standard using a purpose-built facility. The bias and precision uncertainties of the measured torque were ±0.117% and ±0.183%, respectively. To accurately determine the shaft torque developed by a turbine in the OTRF, small corrections due to inertial torque (associated with changes in the rotational speed) and aerodynamic drag (windage) are required. The methods for performing these corrections are described.

Beard, Paul F.; Povey, Thomas

2011-03-01

393

Orion - Super Koropon(Registered Trademark) Torque/Tension Report  

NASA Technical Reports Server (NTRS)

The primary objective of this testing was to obtain torque tension data for the use of Super Koropon Primer Base which was proposed for use on the Orion project. This compound is a corrosion inhibitor/sealer used on threaded fasteners and inserts as specified per NASA/JSC PRC-4004, Sealing of Joints and Faying Surfaces. Some secondary objectives of this testing, were to identify the effect on torque coefficient of several variables. This document contains the outcome of the testing.

Hemminger, Edgar G.; McLeod, Christopher; Peil, John

2012-01-01

394

Prosthetic hand control based on torque estimation from EMG signals  

Microsoft Academic Search

In this paper, we propose a direct torque control method for the prosthetic hand. In order to estimate the joint torque from EMG signals, an artificial neural network by the feedback error learning schema is used. 2-DOF motions, i.e. hand grasping\\/opening and arm flexion\\/extension, are picked up. In the experiments, two measurement conditions of EMG signal are prepared: the forearm

S. Morita; K. Shibatat; X.-Z. Zhengt; K. Ito

2000-01-01

395

Casimir torques between anisotropic boundaries in nematic liquid crystals.  

PubMed

Fluctuation-induced interactions between anisotropic objects immersed in a nematic liquid crystal are shown to depend on the relative orientation of these objects. The resulting long-range "Casimir" torques are explicitly calculated for a simple geometry where elastic effects are absent. Our study generalizes previous discussions restricted to the case of isotropic walls, and leads to new proposals for experimental tests of Casimir forces and torques in nematics. PMID:11497635

Golestanian, R; Ajdari, A; Fournier, J B

2001-08-01

396

Lunar and Solar Torques on the Oceanic Tides  

NASA Technical Reports Server (NTRS)

A general framework for calculating lunar and solar torques on the oceanic tides is developed in terms of harmonic constituents. Axial torques and their associated angular momentum and earth-rotation variations are deduced from recent satellite-altimeter and satellite-tracking tide solutions. Torques on the prograde components of the tide produce the familiar secular braking of the rotation rate. The estimated secular acceleration is approximately -1300 sec/century(sup 2) (less 4% after including atmospheric tides); the implied rate of change in the length of day is 2.28 milliseconds/century. Torques on the retrograde components of the tide produce periodic rotation variations at twice the tidal frequency. Interaction torques, e.g. solar torques on lunar tides, generate a large suite of rotation-rate variations at sums and differences of the original tidal frequencies. These are estimated for periods from 18.6 years to quarter-diurnal. At subdaily periods the angular momentum variations are 5 to 6 orders of magnitude smaller than the variations caused by ocean tidal currents.

Ray, Richard D.; Bills, Bruce G.; Chao, Benjamin Fong

1998-01-01

397

Input torque sensitivity to uncertain parameters in biped robot  

NASA Astrophysics Data System (ADS)

Input torque is themain power to maintain bipedal walking of robot, and can be calculated from trajectory planning and dynamic modeling on biped robot. During bipedal walking, the input torque is usually required to be adjusted due to some uncertain parameters arising from objective or subjective factors in the dynamical model to maintain the pre-planned stable trajectory. Here, a planar 5-link biped robot is used as an illustrating example to investigate the effects of uncertain parameters on the input torques. Kinematic equations of the biped robot are firstly established by the third-order spline curves based on the trajectory planning method, and the dynamic modeling is accomplished by taking both the certain and uncertain parameters into account. Next, several evaluation indices on input torques are introduced to perform sensitivity analysis of the input torque with respect to the uncertain parameters. Finally, based on the Monte Carlo simulation, the values of evaluation indices on input torques are presented, from which all the robot parameters are classified into three categories, i.e., strongly sensitive, sensitive and almost insensitive parameters.

Ding, Chang-Tao; Yang, Shi-Xi; Gan, Chun-Biao

2013-06-01

398

Apparatus to test insertion and removal torque of bone screws.  

PubMed

This paper describes affordable equipment for testing bone screw torque, corresponding to ASTM standard F543-00 for testing metallic medical bone screws. Correct testing of thin and long bone screws is essential due to screw failures during insertion and removal of the screws. Furthermore, insertion torque is an important factor in predicting fixation strength, screw pull-out force and effects of surface treatment of screws. The capability of the custom-built tester was determined using polytetrafluoroethylene and wood disc samples and bone screws. Bovine cortical bones allowed testing to the failure limit, i.e. the torque increased in long screws to the fracture limit. For 2.7 and 3.5 mm thick self-tapping cortical bone screws, the failure torques were 30-50 per cent higher than the minimum values required by the standard (1.0 and 2.3 N m respectively). The equipment provided reproducible results and fulfilled the ASTM standard very well. Preliminary testing with amorphous diamond coated bone screws showed good durability of the coating and on average 10-15 per cent lower torque values compared with uncoated screws. The equipment can be used to measure insertion and removal torques as described in the standard. Furthermore, it also allows testing of normal screws and bolts. PMID:14702987

Koistinen, A; Santavirta, S; Lappalainen, R

2003-01-01

399

Decoupling torque control system for automotive engine tester  

SciTech Connect

This paper presents a novel decoupling control method of the engine torque control for the automobile engine tester. The engine tester is mainly composed of a dynamometer control system and an engine control system. The conventional engine tester has the problem that the performance of the engine torque control system is deteriorated by the influences of the interference between the dynamometer speed control system and the engine torque control system. The authors proposed the practical engine torque control system based on an observer and an identification system to eliminate the interference of the dynamometer speed control system. The effect of observer's parameter error on the engine torque estimation response was analyzed. According to the result of this analysis, a practical method is proposed to identify the engine inertia moment and the shaft spring coefficient that are parameters of the observer. The authors confirmed through simulation and experiments that the proposed decoupling engine torque control system realizes a robust control system from the interference with the dynamometer speed control system.

Nomura, Masakatsu; Suzuki, Masahiko; Hori, Michitaka; Terashima, Masayuki

2000-04-01

400

Estimates of the dissipative heat and axial torque generated by ocean tides on icy satellites in the outer solar system.  

NASA Astrophysics Data System (ADS)

The tidal flow response generated in a satellite ocean depends strongly on the ocean configuration parameters as these parameters control the form and frequencies of the ocean's natural modes of oscillation; if there is a near match between the form and frequency of one of these natural modes and that of one of the available tidal forcing constituents, the ocean can be resonantly excited, producing a strong tidal response. The fundamental elements of the response are described by the tidal flow and surface fluctuations. Derivative elements of the response include the associated dissipative heat, stress, and forces/torques. The dissipative heat has received much previous attention as it may be important in explaining the heat budget on several of the satellites in the Outer Solar System. While these estimates will be reviewed and compared with the tidal dissipation estimates compiled in Hussman et al. (2010), the primary goal in this presentation is to extend the analysis to consider the tidally generated axial torque on the satellites and the potential consquences for rotation. Interestingly, even a synchronously rotating satellite will, if a global fluid layer is included, experience a complex set of opportunities for torques in both the prograde and retrograde sense. The amplitude and sense of the torque sensitively depends on the ocean parameters controlling the tidal response. This sensitivity, combined with expected feedbacks whereby the tides affect the orbital parameters, suggests that the evolution of the satellite system will experience phases of both prograde and retrograde tidal torques during its evolution. A related point is that parameters of the ocean might be inferred from inferences or observations of torque or rotational deviations. In the panels to the right we show the nondimensional tidal torques associated with obliquity (top) and eccentricity (bottom). The parameters described in the labeling are the fluid density ?, surface gravity g, ocean surface area A, tidal equilibrium height ?F, dissipation quality factor Q,and c=(gh)1/2, cr=?a, with ocean thickness h, rotation rate ?, and radius a. Torque due to tides forced by obliquity as a function of the parameters c/cr and Q. Retrograde ("Westward") and prograde ("Eastward") components shown in left and right panels, respectively. Log10 scale shown in colorbar.

Tyler, R.

2012-09-01

401

Linear-quadratic-Gaussian torque control: Application to a flexible joint of a rehabilitation exoskeleton  

Microsoft Academic Search

A linear-quadratic-Gaussian regulator is proposed for the torque control of flexible robotic joints with built-in torque sensor. The regulator requires the joint-torque sensor information only and features: (1) a Kalman filter that, beside reducing the noise and evaluating the derivative of the torque sensor measure, is able to estimate all the external and internal torques acting on the joint; 2)

Rocco Vertechy; Antonio Frisoli; Massimiliano Solazzi; Andrea Dettori; Massimo Bergamasco

2010-01-01

402

Minimization of torque pulsations in a trapezoidal back-EMF permanent magnet brushless DC motor  

Microsoft Academic Search

This paper discusses the different methods used to reduce the torque pulsations (i.e. cogging torque and torque ripple) in a trapezoidal back-EMF permanent magnet (PM) brushless DC motor. The paper covers the design options to reduce both cogging torque and torque ripple. The effect of stator ampere-turns, the influence of rotor magnetization and the effect of the processing of electrical

Sunil Murthy; Benoit Derouane; Buyun Liu; Tomy Sebastian

1999-01-01

403

`Pugnatron'-like reaction in a patient with familial dystonia: torque induced motion analysis  

PubMed Central

A patient is described who suffered from an unusual extrapyramidal syndrome involving both legs and one arm. In the affected parts there was an extreme degree of rigidity. Measurements have been made of the motion that occurred as a result of applying force to the left foot. The torque was provided by a printed motor. The effect of a maintained plantar flexing force was anomalous for the foot moved to a dorsiflexed position. A model illustrating possible principles of feedback control—the Pugnatron—is described. Images

Walsh, E. Geoffrey

1974-01-01

404

Negative thrust and torque characteristics of an adjustable-pitch metal propeller  

NASA Technical Reports Server (NTRS)

This report presents the results of a series of negative thrust and torque measurements made with a 4 foot diameter model of a conventional aluminum-alloy propeller. The tests were made in the 20-foot propeller-research tunnel of the National Advisory Committee for Aeronautics. The results show that the negative thrust is considerably affected by the shape and size of the body behind the propeller, that the maximum negative thrust increases with decrease in blade-angle setting, and that the drag of a locked propeller may be greatly reduced by feathering it into the wind. Several examples of possible applications of the data are given.

Hartman, Edwin P

1934-01-01

405

Effect of magnetic properties of non-oriented electrical steel on torque characteristics of interior-permanent-magnet synchronous motor  

NASA Astrophysics Data System (ADS)

The torque characteristics of interior-permanent-magnet synchronous motor (IPMSM), in which core materials were our conventional non-oriented electrical steel 35SX250 and our developed steels 35SXH, 27SXH with high permeability, were measured by a pulse wave modulation (PWM) inverter control. The torque characteristics of the motor with developed steels were superior to that of conventional steel. The advantage of developed steels was remarkable in the high-toque region. Experimental torque separation using current phase control showed that reluctance torque was strongly affected by the magnetic properties of core materials. And we did magnetic field analysis of the motors by finite element method (FEM). The flux density in the teeth of the stator core was higher in the high permeability steels than that in the conventional steel under the same current condition. The developed steels are expected to be suited to the stator material of IPMSM used as drive motors for electric vehicles and compressor motors for air conditioner.

Fujimura, Hiroshi; Nitomi, Hirokatsu; Yashiki, Hiroyoshi

406

A novel direct torque control for interior permanent-magnet synchronous machine drive with low ripple in torque and flux-a speed-sensorless approach  

Microsoft Academic Search

A novel direct torque control (DTC) scheme for an interior permanent magnet synchronous machine (IPMSM) is proposed in this paper, which features low torque and flux ripple and almost fixed switching frequency. The torque and flux ripples have been significantly reduced compared with those of the basic DTC reported in the literature. A speed estimation scheme is integrated with the

Lixin Tang; Limin Zhong; Muhammed Fazlur Rahman; Yuwen Hu

2003-01-01

407

Ankle and hip postural strategies defined by joint torques  

NASA Technical Reports Server (NTRS)

Previous studies have identified two discrete strategies for the control of posture in the sagittal plane based on EMG activations, body kinematics, and ground reaction forces. The ankle strategy was characterized by body sway resembling a single-segment-inverted pendulum and was elicited on flat support surfaces. In contrast, the hip strategy was characterized by body sway resembling a double-segment inverted pendulum divided at the hip and was elicited on short or compliant support surfaces. However, biomechanical optimization models have suggested that hip strategy should be observed in response to fast translations on a flat surface also, provided the feet are constrained to remain in contact with the floor and the knee is constrained to remain straight. The purpose of this study was to examine the experimental evidence for hip strategy in postural responses to backward translations of a flat support surface and to determine whether analyses of joint torques would provide evidence for two separate postural strategies. Normal subjects standing on a flat support surface were translated backward with a range of velocities from fast (55 cm/s) to slow (5 cm/s). EMG activations and joint kinematics showed pattern changes consistent with previous experimental descriptions of mixed hip and ankle strategy with increasing platform velocity. Joint torque analyses revealed the addition of a hip flexor torque to the ankle plantarflexor torque during fast translations. This finding indicates the addition of hip strategy to ankle strategy to produce a continuum of postural responses. Hip torque without accompanying ankle torque (pure hip strategy) was not observed. Although postural control strategies have previously been defined by how the body moves, we conclude that joint torques, which indicate how body movements are produced, are useful in defining postural control strategies. These results also illustrate how the biomechanics of the body can transform discrete control patterns into a continuum of postural corrections.

Runge, C. F.; Shupert, C. L.; Horak, F. B.; Zajac, F. E.; Peterson, B. W. (Principal Investigator)

1999-01-01

408

Production of peritrichate bacterionanofibers and their proteinaceous components by Acinetobacter sp. Tol 5 cells affected by growth substrates.  

PubMed

The toluene-degrading bacterium Acinetobacter sp. Tol 5 is highly adhesive through cell-surface nanofibers. Previously, we identified two morphologically distinct nanofibers on Tol 5 cells, namely, nonperitrichate anchor-like and peritrichate pilus-like nanofibers. In the present study, the application of improved electron microscopy techniques enabled discrimination of three distinct types of peritrichate nanofibers on Tol 5 cells. Interestingly, production of these nanofibers was affected by the available growth substrate. Thick, long, straight nanofibers a, which were present on cells grown on toluene, lactate, and ethanol, were not observed on cells grown on triacylglycerol (TAG). In contrast, cells grown on TAG were covered with long, curved nanofibers c, which only existed sparsely on cells grown on toluene, lactate, and ethanol. Thin, short, straight nanofibers b were found densely covering the margin of cells grown on all four growth substrates. SDS-PAGE of Tol 5 cell-surface proteins detected a protein of 17.5 kDa that was expressed at a high level on ethanol, but was undetectable on TAG. Conversely, a 26kDa protein was identified that was exclusively expressed on TAG, but was only faintly expressed by cells grown on the other substrates. Based on N-terminal amino acid sequences, the 17.5 and 26 kDa proteins were identified as the major subunits of type 1 and Fil pili, respectively, which are typical bacterionanofibers. From these results, we deduced that nanofibers a and c are type 1 and Fil pili, respectively. The adhesiveness of Tol 5 cells was low only when they were grown on TAG. PMID:20855232

Hori, Katsutoshi; Ishikawa, Masahito; Yamada, Mariko; Higuchi, Aisuke; Ishikawa, Yu; Ebi, Hironori

2011-01-01

409

Isometric, isotonic, and isokinetic torque variations in four muscle groups through a range of joint motion.  

PubMed

The purpose of this investigation was to describe and examine variations in maximal torque produced by knee extension, knee flexion, elbow extension, and elbow flexion through a range of joint motion. Subjects were young, healthy men (n = 16) and women (n = 15). Torque was measured isometrically and isokinetically using a modified Cybex apparatus. Isotonic torque was calculated from a one-repetition maximum using a modified N-K device. Joint angles were monitored with an electrogoniometer. Torque-joint angle curves were constructed for both men and women for each muscle group. Isometric torque was highest, followed by isotonic and isokinetic torque. Torque declined with increasing isokinetic velocity. The angle of peak torque was found to be highly variable in individual subjects. Variations in torque curves were explained in terms of mechanical characteristics of the musculoskeletal system. Muscle group capability was generally found to be well matched to the mechanical requirements of the movement. PMID:6856681

Knapik, J J; Wright, J E; Mawdsley, R H; Braun, J

1983-06-01

410

Torque control system for engine performance test machine for internal combustion engines  

US Patent & Trademark Office Database

A torque control system for an engine performance test machine for internal combustion engines comprises an oscillating type electric dynamometer including a rotor and an oscillating member being oscillatably supported around said rotor and a connecting device for interconnecting the rotor shaft and the rotating member of the engine. The torque control system also includes a load cell for monitoring oscillating torque of the oscillating member, means for generating a first torque occurring at the rotor, means for generating a second torque occurring at the rotating member. The torque control system also includes means for generating a detection signal representative of the sum of said oscillating torque, and the first and second torques, and a controller for adjusting the torque generated by the engine in response to the detection signal.

1991-02-26

411

Nanomagnonic devices based on the spin-transfer torque.  

PubMed

Magnonics is based on signal transmission and processing by spin waves (or their quanta, called magnons) propagating in a magnetic medium. In the same way as nanoplasmonics makes use of metallic nanostructures to confine and guide optical-frequency plasmon-polaritons, nanomagnonics uses nanoscale magnetic waveguides to control the propagation of spin waves. Recent advances in the physics of nanomagnetism, such as the discovery of spin-transfer torque, have created possibilities for nanomagnonics. In particular, it was recently demonstrated that nanocontact spin-torque devices can radiate spin waves, serving as local nanoscale sources of signals for magnonic applications. However, the integration of spin-torque sources with nanoscale magnetic waveguides, which is necessary for the implementation of integrated spin-torque magnonic circuits, has not been achieved to date. Here, we suggest and experimentally demonstrate a new approach to this integration, utilizing dipolar field-induced magnonic nanowaveguides. The waveguides exhibit good spectral matching with spin-torque nano-oscillators and enable efficient directional transmission of spin waves. Our results provide a practical route for the implementation of integrated magnonic circuits utilizing spin transfer. PMID:24813697

Urazhdin, S; Demidov, V E; Ulrichs, H; Kendziorczyk, T; Kuhn, T; Leuthold, J; Wilde, G; Demokritov, S O

2014-07-01

412

Thermal reversal with a spin-transfer torque  

NASA Astrophysics Data System (ADS)

Recent theoretical and experimental studies have shown the presence of the spin-transfer torque (STT) when a current is applied to a spin valve pillar structure. The salient feature of this spin transfer torque is its non-conservative property, i.e., STT can not be written as a magnetization gradient of an energy function. Therefore, the magnetization dynamics as well as thermally assisted reversal show many un-anticipated behaviors. For example, the concept of the energy barrier is ill-defined in the presence of the spin torque and thus the commonly used Brown's formula ( ?=?0 exp[E_b/k_BT]) for the lifetime ? of the thermal reversal is no longer valid. By using the Planck-Fokker equation in combination with micromagnetic simulation, we determine the relaxation time at arbitrary strength of spin torque and magnetic field. We have found that one may still introduce an effective energy barrier to describe thermal agitation, but the actual trajectory of the magnetization vector does not necessarily pass through the saddle points of the effective energy surface. Also, we have obtained the scaling relation between the effective barrier and the spin torque. Research is supported by NSF(ECS-0223568) and INISC.

Li, Zhanjie; Zhang, Shufeng

2003-03-01

413

Eddy Current Sensing of Torque in Rotating Shafts  

NASA Astrophysics Data System (ADS)

The noncontact torque sensing in machine shafts is addressed based on the stress induced in a press-fitted magnetoelastic sleeve on the shaft and eddy current sensing of the changes of electrical conductivity and magnetic permeability due to the presence of stress. The eddy current probe uses dual drive, dual sensing coils whose purpose is increased sensitivity to torque and decreased sensitivity to variations in distance between probe and shaft (liftoff). A mechanism of keeping the distance constant is also employed. Both the probe and the magnetoelastic sleeve are evaluated for performance using a standard eddy current instrument. An eddy current instrument is also used to drive the coils and analyze the torque data. The method and sensor described are general and adaptable to a variety of applications. The sensor is suitable for static and rotating shafts, is independent of shaft diameter and operational over a large range of torques. The torque sensor uses a differential eddy current measurement resulting in cancellation of common mode effects including temperature and vibrations.

Varonis, Orestes J.; Ida, Nathan

2013-12-01

414

40 CFR Table 11 to Subpart Xxxx of... - Minimum Data for Continuous Compliance With the Emission Limits for Tire Cord Production Affected...  

Code of Federal Regulations, 2013 CFR

...Emission Limits for Tire Cord Production Affected Sources 11 Table 11 to Subpart XXXX of Part 63 Protection of Environment...Rubber Tire Manufacturing Pt. 63, Subpt. XXXX, Table 11 Table 11 to Subpart XXXX of Part 63âMinimum...

2013-07-01

415

Young Consumers’ Responses to Event Sponsorship Advertisements of Unhealthy Products: Implications of Schema-triggered Affect Theory  

Microsoft Academic Search

There is growing concern over commercial promotions of products that are unhealthy or unsafe. In some cases, policy recommendations have called for restrictions on promotional activities, such as event sponsorship, when used to promote products like alcohol, tobacco, and fast (\\

Stephen R. McDaniel; Gary R. Heald

2000-01-01

416

Subtask 1.7 Evaluations of Key Factors Affecting Successful Oil Production in the Bakken Formation, North Dakota Phase 2.  

National Technical Information Service (NTIS)

Production from the Bakken and Three Forks Formations continues to trend upward as forecasts predict significant production of oil from unconventional resources nationwide. As the U.S. Geological Survey reevaluates the 3.65 billion bbl technically recover...

D. D. Schmidt D. J. Knudsen E. N. Steadman J. A. Harju J. A. Sorensen S. A. Smith

2011-01-01

417

A testing machine for dental air-turbine handpiece characteristics: free-running speed, stall torque, bearing resistance.  

PubMed

The measurement of performance characteristics of dental air turbine handpieces is of interest with respect to product comparisons, standards specifications and monitoring of bearing longevity in clinical service. Previously, however, bulky and expensive laboratory equipment was required. A portable test machine is described for determining three key characteristics of dental air-turbine handpieces: free-running speed, stall torque and bearing resistance. It relies on a special circuit design for performing a hardware integration of a force signal with respect to rotational position, independent of the rate at which the turbine is allowed to turn during both stall torque and bearing resistance measurements. Free-running speed without the introduction of any imbalance can be readily monitored. From the essential linear relationship between torque and speed, dynamic torque and, hence, power, can then be calculated. In order for these measurements to be performed routinely with the necessary precision of location on the test stage, a detailed procedure for ensuring proper gripping of the handpiece is described. The machine may be used to verify performance claims, standard compliance checks should this be established as appropriate, monitor deterioration with time and usage in the clinical environment and for laboratory investigation of design development. PMID:15765954

Darvell, Brain W; Dyson, J E

2005-01-01

418

Structural transitions in DNA driven by external force and torque  

NASA Astrophysics Data System (ADS)

Experiments on single DNA molecules have shown that abrupt transitions between states of different extensions can be driven by stretching and twisting. Here we show how a simple statistical-mechanical model can be used to globally fit experimental force-extension data of Léger et al. [Phys. Rev. Lett. 83, 1066 (1999)], over a wide range of DNA molecule twisting. We obtain the mean twists, extensions, and free energies of the five DNA states found experimentally. We also predict global force-torque and force-linking number phase diagrams for DNA. At zero force, the unwinding torque for zero-force structural transition from the double helix to an unwound structure is found to be ~-2kBT, while the right-handed torque needed to drive DNA to a highly overwound state ~7kBT.

Sarkar, Abhijit; Léger, Jean-Francois; Chatenay, Didier; Marko, John F.

2001-05-01

419

Non-linear dynamics of the corotation torque  

NASA Astrophysics Data System (ADS)

The excitation of spiral waves by an external perturbation in a disc deposits angular momentum in the vicinity of the corotation resonance (the radius where the speed of a rotating pattern matches the local rotation rate). We use matched asymptotic expansions to derive a reduced model that captures non-linear dynamics of the resulting torque and fluid motions. The model is similar to that derived for forced Rossby wave critical layers in geophysical fluid dynamics. Using the model we explore the saturation of the corotation torque, which occurs when the background potential (specific) vorticity is redistributed by the disturbance. We also consider the effects of dissipation. If there is a radial transport of potential vorticity, the corotation torque does not saturate. The main application is to the creation, growth and migration of protoplanets within discs like the primordial solar nebula. The disturbance also nucleates vortices in the vicinity of corotation, which may spark further epochs of planet formation.

Balmforth, N. J.; Korycansky, D. G.

2001-09-01

420

Study of ball bearing torque under elastohydrodynamic lubrication  

NASA Technical Reports Server (NTRS)

Spinning and rolling torques were measured in an angular-contact ball bearing with and without a cage under several lubrication regimes in a modified NASA spinning torque apparatus. Two lubricants were used - a di-2 ethylhexyl sebacate and a synthetic paraffinic oil, at shaft speeds of 1000, 2000, and 3000 rpm and bearing loads from 45 newtons (10 lb) to 403 newtons (90 lb). An analytical model was developed from previous spinning friction models to include rolling with spinning under lubrication regimes from thin film to flooded conditions. The bearing torque values have a wide variation, under any condition of speed and load, depending on the amount of lubricant present in the bearing. The analytical model compared favorably with experimental results under several lubrication regimes.

Townsend, D. P.; Zaretsky, E. V.; Allen, C. W.

1973-01-01

421

Study of ball bearing torque under elastohydrodynamic lubrication  

NASA Technical Reports Server (NTRS)

Spinning and rolling torques were measured in an angular-contact ball bearing with and without a cage under several lubrication regimes in a modified NASA spinning torque apparatus. Two lubricants were used, a di-2 ethylhexyl sebacate and a synthetic paraffinic oil, at shaft speeds of 1000, 2000, and 3000 rpm and bearing loads from 10 lbs to 90 lbs. An analytical model was developed from previous spinning friction models to include rolling with spinning under lubrication regimes from thin film to flooded conditions. The bearing torque values have a wide variation, under any condition of speed and load, depending on the amount of lubricant present in the bearing. The analytical model compared favorably with experimental results under several lubrication regimes.

Townsend, D. P.; Allen, C. W.; Zaretsky, E. V.

1973-01-01

422

Reverse torque testing and early loading failures: help or hindrance?  

PubMed

Reverse torque testing has been suggested to reduce the incidence of early loading failures during the first year of loading. However, the variables of bone density at stage II uncovery, the assessment of a small degree of implant rotation, and the effect of implant size and design have not been adequately evaluated. In addition, bone is weakest to shear forces, yet this is the primary force applied with reverse torque testing. This article reviews the benefits and disadvantages of reverse torque testing and suggests early crestal bone loss and failure of implants may be the result of this test, especially in less dense bone types. In addition, a nomenclature of implant failures is introduced to improve the correlation of information in the literature to the failure of implants in clinical practice. PMID:11831335

Jividen, G; Misch, C E

2000-01-01

423

Torque transfer coefficient in DNA under torsional stress  

NASA Astrophysics Data System (ADS)

In recent years, significant progress in understanding the properties of supercoiled DNA has been obtained due to nanotechniques that made stretching and twisting of single molecules possible. Quantitative interpretation of such experiments requires accurate knowledge of torques inside manipulated DNA. This paper argues that it is not possible to transfer the entire magnitudes of external torques to the twisting stress of the double helix, and that a reducing torque transfer coefficient (TTC<1) should always be assumed. This assertion agrees with simple physical intuition and is supported by the results of all-atom molecular dynamics (MD) simulations. According to MD, the TTCs around 0.8 are observed in nearly optimal conditions. Reaching higher values requires special efforts and it should be difficult in practice. The TTC can be partially responsible for the persistent discrepancies between the twisting rigidity of DNA measured by different methods.

Mazur, Alexey K.

2012-07-01

424

Radiation torque on nonspherical particles in the transition matrix formalism.  

PubMed

The torque exerted by radiation on small particles is recognized to have a considerable relevance, e.g., on the dynamics of cosmic dust grains and for the manipulation of micro and nanoparticles under controlled conditions. In the present paper we derive, in the transition matrix formalism, the radiation torque applied by a plane polarized wave on nonspherical particles. In case of circularly polarized waves impinging on spherical particles our equations reproduce the findings of Marston and Crichton [Phys. Rev. A 30, 2508-2516 (1984)]. Our equations were applied to calculate the torque on a few model particles shaped as aggregates of identical spheres, both axially symmetric and lacking any symmetry, and the conditions for the stability of the induced rotational motion are discussed. PMID:19529338

Borghese, Ferdinando; Denti, Paolo; Saija, Rosalba; Iatì, Maria A