These are representative sample records from Science.gov related to your search topic.
For comprehensive and current results, perform a real-time search at Science.gov.
1

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] [ORNL; Maxwell, Don E [ORNL] [ORNL; Beer, David [Adaptive Computing] [Adaptive Computing

2013-01-01

2

Torque Production in Permanent-Magnet Synchronous Motor Drives with Rectangular Current Excitation  

Microsoft Academic Search

Special features of torque production in self-controlled permanent-magnet (PM) synchronous motor drives with rectangular current excitation have been investigated. Addressed issues include the generation of undesired torque pulsations at low speeds and system operating locus limits imposed at high speeds by saturation of the current regulator. Attention is limited to motors in which sources of reluctance torque are suppressed by

Thomas M. Jahns

1984-01-01

3

The influence of crank configuration on muscle activity and torque production during arm crank ergometry.  

PubMed

This study investigated the effect of crank configuration on muscle activity and torque production during submaximal arm crank ergometry. Thirteen non-specifically trained male participants volunteered. During the research trials they completed a warm-up at 15W before two 3-min exercise stages were completed at 50 and 100W; subjects used either a synchronous or asynchronous pattern of cranking. During the final 30-s of each submaximal exercise stage electromyographic and torque production data were collected. After the data had been processed each parameter was analysed using separate 2-way ANOVA tests with repeated measures. The activity of all muscles increased in line with external workload, although a shift in the temporal pattern of muscle activity was noted between crank configurations. Patterns of torque production during asynchronous and synchronous cranking were distinct. Furthermore, peak, minimum and delta (peak-minimum) torque values were different (P<0.05) between crank configurations at both workloads. For example, at 100W, peak torque using synchronous [19.6 (4.3) Nm] cranking was higher (P<0.05) compared to asynchronous [16.8 (1.6) Nm] cranking. In contrast minimum torque was lower (P<0.05) at 100 W using synchronous [4.8 (1.7)Nm] compared to asynchronous [7.3 (1.2)Nm] cranking. There was a distinct bilateral asymmetry in torque production during asynchronous cranking with the dominant transmitting significantly more force to the crank arm. Taken together, these preliminary data demonstrate the complex nature of muscle activity during arm crank ergometry performed with an asynchronous or synchronous crank set-up. Further work is required to determine how muscle activity (EMG activity) and associated patterns of torque production influence physiological responses and functional capacity during arm crank ergometry. PMID:17337211

Smith, Paul M; Chapman, Mark L; Hazlehurst, Kathryn E; Goss-Sampson, Mark A

2008-08-01

4

The framework of product affection  

Microsoft Academic Search

This paper introduces a conceptual framework for the process underlying emotional responses that result from the perception of products. The framework distinguishes different kinds of product affection on the basis of emotional psychology. Accordingly, the product affection is divided into three levels: the reflection emotional level, the basic emotional level, the emotional senior level. By revealing the characteristics of the

J. Q. Mao; Y. H. Zhou; H. B. Yang

2009-01-01

5

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

6

Sugars proportionately affect artemisinin production.  

PubMed

Little is known about the effect of sugars in controlling secondary metabolism. In this study, sugars alone or in combination with their analogs were used to investigate their role in the production of the antimalarial drug, artemisinin, in Artemisia annua L. seedlings. Compared to sucrose, a 200% increase in artemisinin by glucose was observed. Different ratios of fructose to glucose yielded artemisinin levels directly proportional to increases in relative glucose concentration. When the glucose analog, 3-O-methylglucose, was added with glucose, artemisinin production was dramatically decreased, but hexokinase activity was significantly increased compared to glucose alone. In contrast, neither mannose nor mannitol had any significant effect on artemisinin yield. In comparison with 30 g/l sucrose, artemisinin levels were significantly reduced by 80% in the presence of 27 g/l sucrose + 3 g/l palatinose, which cannot be transported into cells through the sucrose transporter. Together these results suggest that both monosaccharide and disaccharide sugars are likely acting not only as carbon sources but also as signals to affect the downstream production of artemisinin, and that the mechanism of these effects appears to be complex. PMID:17221224

Wang, Y; Weathers, P J

2007-07-01

7

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

8

The Eccentric Torque Production Capacity of the Ankle, Knee, and Hip Muscle Groups in Patients with Unilateral Chronic Ankle Instability  

PubMed Central

Purpose The aim of this study was to investigate eccentric torque production capacity of the ankle, knee and hip muscle groups in patients with unilateral chronic ankle instability (CAI) as compared to healthy matched controls. Methods In this case-control study, 40 participants (20 with CAI and 20 controls) were recruited based on convenient non-probability sampling. The average peak torque to body weight (APT/BW) ratio of reciprocal eccentric contraction of ankle dorsi flexor/plantar flexor, ankle evertor/invertor, knee flexor/extensor, hip flexor/extensor and hip abductor/adductor was determined using an isokinetic dynamometer. All subjects participated in two separate sessions with a rest interval of 48 to 72 hours. In each testing session, the torque production capacity of the ankle, knee, and hip muscle groups of only one lower limb was measured. At first, 3 repetitions of maximal eccentric-eccentric contraction were performed for the reciprocal muscles of a joint in a given movement direction. Then, the same procedure of practice and testing trials was repeated for the next randomly-ordered muscle group or joint of the same limb. Results There was no significant interaction of group (CAI and healthy controls) by limb (injured and non-injured) for any muscle groups. Main effect of limb was not significant. Main effect of group was only significant for eccentric torque production capacity of ankle dorsi flexor and hip flexor muscle groups. The APT/BW ratio of these muscles was significantly lower in the CAI group than the healthy controls (P<0.05). Conclusion CAI is associated with eccentric strength deficit of ankle dorsi flexor and hip flexor muscles as indicated by reduction in torque production capacity of these muscles compared to healthy controls. This strength deficit appeared to exist in both the injured and non-injured limbs of the patients. PMID:23802057

Negahban, Hossein; Moradi-Bousari, Aida; Naghibi, Saeed; Sarrafzadeh, Javad; Shaterzadeh-Yazdi, Mohammad-Jafar; Goharpey, Shahin; Etemadi, Malihe; Mazaheri, Masood; Feizi, Awat

2013-01-01

9

Amplitude and frequency measures of surface electromyography during dual task elbow torque production  

Microsoft Academic Search

Summary  Studies of motor unit recruitment thresholds have demonstrated the existence of task-specific motor units within the muscles controlling the elbow. Two degree-of-freedom (df) task specificity was investigated at higher levels of elbow torque using the amplitude and frequency characteristics of surface electromyography (EMG). Flexion and supination torque data were collected together with EMG from electrode pairs on the brachioradialis (BRAD),

G. E. Caldwell; J. C. Jamison; S. Lee

1993-01-01

10

Leg dominancy in relation to fast isometric torque production and squat jump height  

Microsoft Academic Search

We hypothesized that maximal unilateral isometric knee extensor torque, the rate of torque development during maximally fast\\u000a isometric contractions and unilateral squat jump performance would be better with the dominant than non-dominant leg. Limb\\u000a dominancy was established using the step up, balance recovery, and ball kick test. On two days, eight men (21.5 ± 2.2 years,\\u000a means ± SD) performed unilateral maximal isometric contractions with

Cornelis Jo de Ruiter; Alex de Korte; Sander Schreven; Arnold de Haan

2010-01-01

11

Conventionally assessed voluntary activation does not represent relative voluntary torque production  

PubMed Central

The ability to voluntarily activate a muscle is commonly assessed by some variant of the twitch interpolation technique (ITT), which assumes that the stimulated force increment decreases linearly as voluntary force increases. In the present study, subjects (n = 7) with exceptional ability for maximal voluntary activation (VA) of the knee extensors were used to study the relationship between superimposed and voluntary torque. This includes very high contraction intensities (90–100%VA), which are difficult to consistently obtain in regular healthy subjects (VA of ?90%). Subjects were tested at 30, 60, and 90° knee angles on two experimental days. At each angle, isometric knee extensions were performed with supramaximal superimposed nerve stimulation (triplet: three pulses at 300 Hz). Surface EMG signals were obtained from rectus femoris, vastus lateralis, and medialis muscles. Maximal VA was similar and very high across knee angles: 97 ± 2.3% (mean ± SD). At high contraction intensities, the increase in voluntary torque was far greater than would be expected based on the decrement of superimposed torque. When voluntary torque increased from 79.6 ± 6.1 to 100%MVC, superimposed torque decreased from 8.5 ± 2.6 to 2.8 ± 2.3% of resting triplet. Therefore, an increase in VA of 5.7% (from 91.5 ± 2.6 to 97 ± 2.3%) coincided with a much larger increase in voluntary torque (20.4 ± 6.1%MVC) and EMG (33.9 ± 6.6%max). Moreover, a conventionally assessed VA of 91.5 ± 2.6% represented a voluntary torque of only 79.6 ± 6.1%MVC. In conclusion, when maximal VA is calculated to be ?90% (as in regular healthy subjects), this probably represents a considerable overestimation of the subjects’ ability to maximally drive their quadriceps muscles. PMID:17357793

Kooistra, R. D.; de Ruiter, C. J.

2007-01-01

12

Electric field driven torque in ATP synthase.  

PubMed

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. PMID:24040370

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

2013-01-01

13

Hex ball torque test  

NASA Technical Reports Server (NTRS)

A series of torque tests were performed on four flight-type hex ball universal joints in order to characterize and determine the actual load-carrying capability of this device. The universal joint is a part of manual actuation rods for scientific instruments within the Hubble Space Telescope. It was found that the hex ball will bind slightly during the initial load application. This binding did not affect the function of the universal joint, and the units would wear-in after a few additional loading cycles. The torsional yield load was approximately 50 ft-lb, and was consistent among the four test specimens. Also, the torque required to cause complete failure exceeded 80 ft-lb. It is concluded that the hex ball universal joint is suitable for its intended applications.

Robinson, B. A.; Foster, C. L.

1986-01-01

14

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

15

Power tong torque control  

Microsoft Academic Search

Torque controlled powered pipe tongs, are described the apparatus comprises: (a) a power tong powered by a fluid motor; (b) a fluid power source connected to the motor; (c) a force conducting element attached to the power tong, situated to oppose reaction torque from the tongs when torque is applied to pipe; (d) force sensing means operatively associated with the

D. A. Buck; R. N. James

1987-01-01

16

Chapter 2 Climate Change Affecting Rice Production  

Microsoft Academic Search

This review addresses possible adaptation strategies in rice production to abiotic stresses that will aggravate under climate change: heat (high temperature and humidity), drought, salinity, and submergence. Each stress is discussed regarding the current state of knowledge on damage mechanism for rice plants as well as possible developments in germplasm and crop management technologies to overcome production losses. Higher temperatures

R. Wassmann; S. V. K. Jagadish; S. Heuer; A. Ismail; E. Redona; R. Serraj; R. K. Singh; G. Howell; H. Pathak; K. Sumfleth

2009-01-01

17

Torque production in the shoulder of the normal young adult maleThe interaction of function, dominance, joint angle, and angular velocity  

Microsoft Academic Search

Shoulder torque measurements were obtained from 36 normal young adult males during flexion, abduction, internal rotation, and external rotation. Normative, an gle-specific torque measurements were determined un der isometric conditions and isokinetically at 48 deg\\/ sec. The effects of dominance, angular velocity, and joint position were determined and a method provided for determining the expected maximal torque at a spe

James C. Otis; Russell F. Warren; Sherry I. Backus; Thomas J. Santner; Jay D. Mabrey

1990-01-01

18

Analytical Modeling and Evaluation of Affective Product Ecosystems  

Microsoft Academic Search

The consideration of human-product-environment interactions is consistent with the wisdom of 'product ecosystems', which essentially entail a scenario of affective design of the entire system with customer experience in the loop. The 'emotional' aspects play an important role in forming customer perception, and thus to influence the performance of product ecosystem design. This paper developed an analytical model for product

ROGER J. JIAO; MARTIN HELANDER; YIYANG ZHANG; JUN DU; QIANLI XU

19

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

20

Analytical Affect Modeling and Evaluation for Product Ecosystems  

Microsoft Academic Search

Background A better understanding of human cognitive and affective capacities will likely lead to new applications, products and\\/or services, spanning a whole range of potential industries. The potential of affect evaluation has been observed by a few industrial initiatives including IBM's and Philips' initiatives in pervasive computing. Philips Design has launched a number of large projects such as Vision of

Roger J. Jiao; Martin Helander

21

Feasibility of estimating isokinetic knee torque using a neural network model  

Microsoft Academic Search

Many studies have investigated the relationships between electromyography (EMG) and torque production. A few investigators have used adjusted learning algorithms and feed-forward artificial neural networks (ANNs) to estimate joint torque in the elbow. This study sought to estimate net isokinetic knee torque using ANN models. Isokinetic knee extensor and flexor torque data were measured simultaneously with agonist and antagonist EMG

Michael E. Hahn

2007-01-01

22

Dynamics of railway wagons subjected to braking\\/traction torque  

Microsoft Academic Search

Braking or traction torque is regarded as an important source of wheelset skid and a potential source of derailment risk that adversely affects the safety levels of train operations; therefore, this research examines the effect of braking\\/traction torque to the longitudinal and lateral dynamics of wagons. This paper reports how train operations safety could be adversely affected due to various

Zuoyan Zhang; Manicka Dhanasekar

2009-01-01

23

Factors affecting fruit and seed production in Dactylorhiza maculata (Orchidaceae)  

Microsoft Academic Search

It has been argued that some of resources needed for fruit and seed production in terrestrial orchids originate from storage in underground biomass. Resources for female reproductive traits may also originate from current photosynthesis. Orchid mycorrhiza may also influence fruit and seed production. The extent to which current photosynthetic activity and nutrient uptake via mycorrhizal fungi affect fruit and seed

ELISA VALLIUS

2001-01-01

24

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

25

Predicting shaft torque amplification  

SciTech Connect

Shaft Torque Amplification (STA) is the form of SSR characterized by the higher system-model complexity and computational requirements its simulation, normally in a time-domain environment, demands. A multi-modal approach drawing the turbogenerator torsional response to electrical torque impulses applied to the machine air-gap is introduced in this article as an alternative STA analysis frame. Peak torque results from the proposed algorithm are compared with similar ones obtained from EMTP runs. Loss-of-life calculations and a capacitor-reinsertion application as STA control means, are included.

Achilles, R.A. [Achilles (R.A.), Neuquen (Argentina)] [Achilles (R.A.), Neuquen (Argentina)

1995-02-01

26

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

27

Displaceable Gear Torque Controlled Driver  

NASA Technical Reports Server (NTRS)

Methods and apparatus are provided for a torque driver including a displaceable gear to limit torque transfer to a fastener at a precisely controlled torque limit. A biasing assembly biases a first gear into engagement with a second gear for torque transfer between the first and second gear. The biasing assembly includes a pressurized cylinder controlled at a constant pressure that corresponds to a torque limit. A calibrated gage and valve is used to set the desired torque limit. One or more coiled output linkages connect the first gear with the fastener adaptor which may be a socket for a nut. A gear tooth profile provides a separation force that overcomes the bias to limit torque at the desired torque limit. Multiple fasteners may be rotated simultaneously to a desired torque limit if additional output spur gears are provided. The torque limit is adjustable and may be different for fasteners within the same fastener configuration.

Cook, Joseph S., Jr. (Inventor)

1997-01-01

28

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

29

Negative Optical Torque  

NASA Astrophysics Data System (ADS)

Light carries angular momentum, and as such it can exert torques on material objects. Applications of these opto-mechanical effects were limited initially due to their smallness in magnitude, but later becomes powerful and versatile after the invention of laser. Novel and practical approaches for harvesting light for particle rotation have since been demonstrated, where the structure is always subjected to a positive optical torque along a certain axis if the incident angular momentum has a positive projection on the same axis. We report here an interesting phenomenon of ``negative optical torque'', meaning that incoming photons carrying angular momentum rotate an object in the opposite sense. Surprisingly this can be realized quite straightforwardly in simple planar structures. Field retardation is a necessary condition and discrete rotational symmetry of material object plays an important role. The optimal conditions are explored and explained.

Chen, Jun; Ng, Jack; Ding, Kun; Fung, Kin Hung; Lin, Zhifang; Chan, C. T.

2014-09-01

30

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

31

MET2 affects production of hydrogen sulfide during wine fermentation.  

PubMed

The production of hydrogen sulfide (H2S) during yeast fermentation contributes negatively to wine aroma. We have mapped naturally occurring mutations in commercial wine strains that affect production of H2S. A dominant R310G mutant allele of MET2, which encodes homoserine O-acetyltransferase, is present in several wine yeast strains as well as in the main lab strain S288c. Reciprocal hemizygosity and allele swap experiments demonstrated that the MET2 R310G allele confers reduced H2S production. Mutations were also identified in genes encoding the two subunits of sulfite reductase, MET5 and MET10, which were associated with reduced H2S production. The most severe of these, an allele of MET10, showed five additional phenotypes: reduced growth rate on sulfate, elevated secretion of sulfite, and reduced production in wine of three volatile sulfur compounds: methionol, carbon disulfide and methylthioacetate. Alleles of MET5 and MET10, but not MET2, affected H2S production measured by colour assays on BiGGY indicator agar, but MET2 effects were seen when bismuth was added to agar plates made with Sauvignon blanc grape juice. Collectively, the data are consistent with the hypothesis that H2S production during wine fermentation results predominantly from enzyme activity in the sulfur assimilation pathway. Lower H2S production results from mutations that reduce the activity of sulfite reductase, the enzyme that produces H2S, or that increase the activity of L-homoserine-O-acetyltransferase, which produces substrate for the next step in the sulfur assimilation pathway. PMID:24841117

Huang, Chien; Roncoroni, Miguel; Gardner, Richard C

2014-08-01

32

Food and predators affect egg production in song sparrows.  

PubMed

Although the possibility that food and predators may interact in limiting avian populations has long been recognized, there have been few attempts to test this experimentally in the field. We conducted a manipulative food addition experiment on the demography of Song Sparrows (Melospiza melodia) across sites that varied in predator abundance, near Victoria, British Columbia, Canada, over three consecutive breeding seasons. We previously showed that food and predators had interactive effects on annual reproductive success (young fledged per female). Here, we report the effects on egg production. Our results show that food limits the total number of eggs laid over the breeding season ("total egg production") and that interactive food and predator effects, including food effects on nest predation, determine how those eggs are "parceled out" into different nests. Food addition alone significantly affected total egg production, and there was no significant interannual variability in this result. At the same time, both food and predators affected the two determinants of total egg production: "clutch number" (total number of clutches laid) and average clutch size. Both clutch number and size were affected by a food x predator x year interaction. Clutch number was lower at low-predator locations because there was less nest predation and thus less renesting. Food addition also significantly reduced nest predation, but there was significant interannual variation in this effect. This interannual variation was responsible for the food x predator x year interactions because the larger the effect of food on nest predation in a given year, the smaller was the effect of food on clutch number; and the smaller the effect of food on clutch number, the larger was the effect of food on clutch size. Potential predator and year effects on total egg production were thus cancelled out by an inverse relationship between clutch number and clutch size. We suggest that combined food and predator effects on demography could be the norm in both birds and mammals. PMID:17089655

Zanette, Liana; Clinchy, Michael; Smith, James N M

2006-10-01

33

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

34

Estimates of Venusian atmospheric torque  

NASA Astrophysics Data System (ADS)

An estimate is derived of the solar gravitational torque on the thermal atmospheric tide of Venus. The value obtained is compared with the computed torque on the body of the planet itself caused by viscous coupling between it and the superrotating atmosphere. The comparison suggests that the solar thermal torque and the viscous torque are effective in the maintenance of the four-day superrotation of the Venusian atmosphere.

McCue, J.; Dormand, J. R.; Gadian, A. M.

1992-04-01

35

Spark Ignition Engine Torque Management Grant A. Ingram1, Matthew A. Franchek,  

E-print Network

such as AFR, engine speed, mass air flow, spark, and exhaust gas recirculation (EGR) affect engine torque pro. To this end, a system level model of engine torque pro- duction is experimentally determined. Next, a crank the nonlinear system characteristics and pure delay. The controller de- sign methodology applied to the torque

Balakrishnan, Venkataramanan "Ragu"

36

Spark Ignition Engine Torque Management Grant A. Ingram 1 , Matthew A. Franchek,  

E-print Network

such as AFR, engine speed, mass air flow, spark, and exhaust gas recirculation (EGR) affect engine torque pro. To this end, a system level model of engine torque pro­ duction is experimentally determined. Next, a crank the nonlinear system characteristics and pure delay. The controller de­ sign methodology applied to the torque

Balakrishnan, Venkataramanan "Ragu"

37

Torque-Splitting Gear Drive  

NASA Technical Reports Server (NTRS)

Geared drive train transmits torque from input shaft in equal parts along two paths in parallel, then combines torques in single output shaft. Scheme reduces load on teeth of meshing gears while furnishing redundancy to protect against failures. Such splitting and recombination of torques common in design of turbine engines.

Kish, J.

1991-01-01

38

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

39

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

40

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. PMID:18708468

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

2008-01-01

41

Issues in reducing the cogging torque of mass-produced permanent-magnet brushless DC motor  

Microsoft Academic Search

A variety of techniques are available to reduce cogging torque in permanent-magnet brushless DC motors. Theoretically, all the techniques are quite effective for minimizing the cogging torque. This paper presents the efficacy of these methods in mass production subject to manufacturing tolerances\\/variations. The cogging torque minimization becomes a challenging task when the requirement is very stringent in applications such as

Mohammad S. Islam; Sayeed Mir; Tomy Sebastian

2004-01-01

42

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

43

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

44

Thermomagnetic Torque in Nh3  

E-print Network

June 1970) A study of the thermomagnetic torque (Scott effect) in NH3 is reported. The small posi- tive Scott torque is measured as a function of magnetic field for absolute pressures of 0.028, 0.043, 0.048, 0.057, and 0.078 Torr. At maximum torque..., the magnetic field Hp for each pressure P is given by Hp ?-b(P+a), where a=-4. 4&&10 3 Torr and b=3. 18&&103 Oe/Torr. INTRODUCTION In 1967 Scott, Sturner, and Williamson' opened an exciting new field with the discovery of a thermo- magnetic torque on a...

Adair, Thomas W.; McClurg, G. R.

1970-01-01

45

Torque feedback transmission  

SciTech Connect

This patent describes an infinitely variable transmission of inline configuration for interconnecting a primer mover with a load for clutch free operation in a range of speed including hydraulic neutral comprising: a. planetary gear train means having a ring gear, planetary gears supported by a planetary gear carrier, and a sun gear, the sun gear being connected mechanically to the load, output shaft means for joining the sun gear to the load; b. variable torque feedback means comprising (i) a variable displacement hydraulic motor whose rotor shaft is in line with the output shaft means and drivingly connected to the prime mover and the planetary gear carrier during the full range of operation of the transmission, and (ii) a fixed displacement hydraulic pump connected hydraulically to the motor, the rotor shaft of the pump being connected mechanically to the ring gear and being axially displaced from the output shaft means; c. means for adjusting the displacement volume within the hydraulic motor for controlling the torque feedback in the transmission to provide infinitely variable coupling between the prime mover and the load over the full range of the transmission including hydraulic neutral; d. a speed reducer between the primer mover and the motor rotor shaft and a speed multiplier between the sun gear and the load; and e. mechanical transmission assembly means between the speed multiplier and the load in line with the motor rotor shaft and the output shaft means for providing selection of drive, reverse, park, and neutral.

Whalen, B.L.

1987-01-20

46

40 CFR 63.5984 - What emission limits must I meet for tire production affected sources?  

Code of Federal Regulations, 2012 CFR

... false What emission limits must I meet for tire production affected sources? 63.5984 Section...Standards for Hazardous Air Pollutants: Rubber Tire Manufacturing Emission Limits for Tire Production Affected Sources § 63.5984...

2012-07-01

47

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

...2014-07-01 false Emission Limits for Tire Production Affected Sources 1 Table...Standards for Hazardous Air Pollutants: Rubber Tire Manufacturing Pt. 63, Subpt. XXXX...XXXX of Part 63—Emission Limits for Tire Production Affected Sources As...

2014-07-01

48

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

Code of Federal Regulations, 2011 CFR

...2009-07-01 true Emission Limits for Tire Production Affected Sources 1 Table...Standards for Hazardous Air Pollutants: Rubber Tire Manufacturing Pt. 63, Subpt. XXXX...XXXX of Part 63—Emission Limits for Tire Production Affected Sources As...

2011-07-01

49

40 CFR 63.5984 - What emission limits must I meet for tire production affected sources?  

Code of Federal Regulations, 2013 CFR

... true What emission limits must I meet for tire production affected sources? 63.5984 Section...Standards for Hazardous Air Pollutants: Rubber Tire Manufacturing Emission Limits for Tire Production Affected Sources § 63.5984...

2013-07-01

50

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

Code of Federal Regulations, 2010 CFR

...2010-07-01 true Emission Limits for Tire Cord Production Affected Sources 2 ...Standards for Hazardous Air Pollutants: Rubber Tire Manufacturing Pt. 63, Subpt. XXXX...XXXX of Part 63—Emission Limits for Tire Cord Production Affected Sources As...

2010-07-01

51

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

Code of Federal Regulations, 2012 CFR

...2012-07-01 false Emission Limits for Tire Production Affected Sources 1 Table...Standards for Hazardous Air Pollutants: Rubber Tire Manufacturing Pt. 63, Subpt. XXXX...XXXX of Part 63—Emission Limits for Tire Production Affected Sources As...

2012-07-01

52

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

Code of Federal Regulations, 2013 CFR

...2012-07-01 true Emission Limits for Tire Production Affected Sources 1 Table...Standards for Hazardous Air Pollutants: Rubber Tire Manufacturing Pt. 63, Subpt. XXXX...XXXX of Part 63—Emission Limits for Tire Production Affected Sources As...

2013-07-01

53

40 CFR 63.5984 - What emission limits must I meet for tire production affected sources?  

Code of Federal Regulations, 2010 CFR

... true What emission limits must I meet for tire production affected sources? 63.5984 Section...Standards for Hazardous Air Pollutants: Rubber Tire Manufacturing Emission Limits for Tire Production Affected Sources § 63.5984...

2010-07-01

54

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

Code of Federal Regulations, 2011 CFR

...2009-07-01 true Emission Limits for Tire Cord Production Affected Sources 2 ...Standards for Hazardous Air Pollutants: Rubber Tire Manufacturing Pt. 63, Subpt. XXXX...XXXX of Part 63—Emission Limits for Tire Cord Production Affected Sources As...

2011-07-01

55

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

Code of Federal Regulations, 2012 CFR

...2012-07-01 false Emission Limits for Tire Cord Production Affected Sources 2 ...Standards for Hazardous Air Pollutants: Rubber Tire Manufacturing Pt. 63, Subpt. XXXX...XXXX of Part 63—Emission Limits for Tire Cord Production Affected Sources As...

2012-07-01

56

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

...2014-07-01 false Emission Limits for Tire Cord Production Affected Sources 2 ...Standards for Hazardous Air Pollutants: Rubber Tire Manufacturing Pt. 63, Subpt. XXXX...XXXX of Part 63—Emission Limits for Tire Cord Production Affected Sources As...

2014-07-01

57

40 CFR 63.5984 - What emission limits must I meet for tire production affected sources?  

... false What emission limits must I meet for tire production affected sources? 63.5984 Section...Standards for Hazardous Air Pollutants: Rubber Tire Manufacturing Emission Limits for Tire Production Affected Sources § 63.5984...

2014-07-01

58

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

Code of Federal Regulations, 2013 CFR

...2012-07-01 true Emission Limits for Tire Cord Production Affected Sources 2 ...Standards for Hazardous Air Pollutants: Rubber Tire Manufacturing Pt. 63, Subpt. XXXX...XXXX of Part 63—Emission Limits for Tire Cord Production Affected Sources As...

2013-07-01

59

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

Code of Federal Regulations, 2010 CFR

...2010-07-01 true Emission Limits for Tire Production Affected Sources 1 Table...Standards for Hazardous Air Pollutants: Rubber Tire Manufacturing Pt. 63, Subpt. XXXX...XXXX of Part 63—Emission Limits for Tire Production Affected Sources As...

2010-07-01

60

40 CFR 63.5984 - What emission limits must I meet for tire production affected sources?  

Code of Federal Regulations, 2011 CFR

... true What emission limits must I meet for tire production affected sources? 63.5984 Section...Standards for Hazardous Air Pollutants: Rubber Tire Manufacturing Emission Limits for Tire Production Affected Sources § 63.5984...

2011-07-01

61

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

62

High torque miniature rotary actuator  

Microsoft Academic Search

This paper summarizes the design and the development of a miniature rotary actuator (36 mm diameter by 100 mm length) used in spacecraft mechanisms requiring high torques and\\/or ultra-fine step resolution. This actuator lends itself to applications requiring high torque but with strict volume limitations which challenge the use of conventional rotary actuators. The design challenge was to develop a

Ruben Nalbandian

2005-01-01

63

Knowledge Elecitation for Factors Affecting Taskforce Productivity using a Questionnaire  

E-print Network

In this paper we present the process of Knowledge Elicitation through a structured questionnaire technique. This is an effort to depict a problem domain as Investigation of factors affecting taskforce productivity. The problem has to be solved using the expert system technology. This problem is the very first step how to acquire knowledge from the domain experts. Knowledge Elicitation is one of the difficult tasks in knowledge base formation which is a key component of expert system. The questionnaire was distributed among 105 different domain experts of Public and Private Organizations (i.e. Education Institutions, Industries and Research etc) in Pakistan. A total 61 responses from these experts were received. All the experts were well qualified, highly experienced and has been remained the members for selection committees a number of times for different posts. Facts acquired were analyzed from which knowledge was extracted and elicited. A standard shape was given to the questionnaire for further research as a knowledge learning tool. This tool may be used as a standard document for selection and promotion of employees.

Muhammad Sohail; Abdur Rashid Khan

2009-07-30

64

Knowledge of Repetitions Range Affects Force Production in Trained Females  

PubMed Central

Most studies have examined pacing strategies with cyclical activities (running and cycling). It has been demonstrated that males employ different pacing strategies during repeated maximal voluntary contractions (MVCs) dependent upon a known endpoint. Since different fatiguing mechanisms have been identified between the genders, it is not known if females use comparable pacing strategies. The purpose of this study was to examine if informing female subjects regarding the number of MVCs to perform would affect force and electromyography (EMG). Twenty well-trained females completed 3 fatiguing protocols in a randomized order. In the control condition participants were informed they would perform twelve MVCs and then actually completed twelve. In the unknown condition they were not told how many MVCs to perform but were stopped after twelve. In the deception condition they were initially informed to perform 6 MVCs, but after the 6th MVC they were asked to perform a few more MVCs and were stopped after twelve. During the first 6 MVCs, forces in the deception condition were greater compared to the unknown (p = 0.021, ES = 0.65, 5%) and control (p = 0.022, ES = 0.42, 3%) conditions. No differences were found between conditions in the last 6 MVCs. A main effect for repetitions showed force deficits during the first 6 MVCs (p = 0.000, ES = 1.81, 13%) and last 6 MVCs (p = 0.05, ES = 0.34, 3%). No differences were found between conditions in biceps and triceps EMG. However, EMG decreased during the first 6 MVCs for biceps (p = 0.001, ES = 1.0, 14%) and triceps (p = 0.001, ES = 0.76, 14%) across conditions. No differences were found in the last 6 MVCs. The anticipation of performing fewer MVCs led to increased force, whereas no endpoint led to decreased force production. Key points Pacing strategies occur during repeated (fatiguing) MVCs as a function of end point expectations. Females use similar pacing strategies as previously published results with males. Without a known end point, females will tend to pace themselves by decreasing force output even when asked to perform maximal contractions.

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

2014-01-01

65

Variation in Soybean Seed Composition as Affected by Variety and Environment Under Commercial Production in Minnesota  

Microsoft Academic Search

The soybean plant (Glycine max (L.) Merrill) produces a seed rich in protein and oil. Seed composition is greatly affected by both plant genetics and the production environment. Seed composition affects protein levels of a valuable product -- soybean meal; therefore, both buyers and processors have a great interest in genetic and environmental factors affecting soybean seed composition. A survey

S. L. Naeve; T. A. O'Neill; J. H. Orf

66

Zero torque gear head wrench  

NASA Technical Reports Server (NTRS)

A gear head wrench particularly suited for use in applying torque to bolts without transferring torsional stress to bolt-receiving structures is introduced. The wrench is characterized by a coupling including a socket, for connecting a bolt head with a torque multiplying gear train, provided within a housing having an annulus concentrically related to the socket and adapted to be coupled with a spacer interposed between the bolt head and the juxtaposed surface of the bolt-receiving structure for applying a balancing counter-torque to the spacer as torque is applied to the bolt head whereby the bolt-receiving structure is substantially isolated from torsional stress. As a result of the foregoing, the operator of the wrench is substantially isolated from any forces which may be imposed.

Mcdougal, A. R.; Norman, R. M. (inventors)

1976-01-01

67

Magnetically torqued thin accretion disks  

E-print Network

We consider geometrically thin accretion disks around millisecond X-ray pulsars. We start with the Shakura-Sunyaev thin disk model as a basis and modify the disk equations with a magnetic torque from the central neutron ...

Savcheva, Antonia Stefanova

2006-01-01

68

Pressurized fluid torque driver control and method  

NASA Technical Reports Server (NTRS)

Methods and apparatus are provided for a torque driver including a displaceable gear to limit torque transfer to a fastener at a precisely controlled torque limit. A biasing assembly biases a first gear into engagement with a second gear for torque transfer between the first and second gear. The biasing assembly includes a pressurized cylinder controlled at a constant pressure that corresponds to a torque limit. A calibrated gage and valve is used to set the desired torque limit. One or more coiled output linkages connect the first gear with the fastener adaptor which may be a socket for a nut. A gear tooth profile provides a separation force that overcomes the bias to limit torque at the desired torque limit. Multiple fasteners may be rotated simultaneously to a desired torque limit if additional output spur gears are provided. The torque limit is adjustable and may be different for fasteners within the same fastener configuration.

Cook, Joseph S., Jr. (inventor)

1994-01-01

69

Biological Factors Affecting Seed Production in East African Highland Bananas  

Microsoft Academic Search

Seed production from hybridizations involving the East African Highland bananas (Mum spp., AAA group) is low due to high levels of sterility. This is a major impediment for the development of hybrids with disease and pest resistance and superior agronomic traits. The objective of this study was to examine the effect of inflorescence and stigma developmental stages on seed production

R. Ssebuliba; M. Magambo; D. Talengera; D. Makumbi; A. Tenkouano; P. Rubaihayo; M. Pillay

2006-01-01

70

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

71

FACTORS AFFECTING THE PHOTOCHEMICAL PRODUCTION OF CARBONYL SULFIDE IN SEAWATER  

EPA Science Inventory

Our laboratory studies indicate that the photochemical production of carbonyl sulfide (COS) in seawater can result from the photosensitized reaction of organosulfur compounds. Because natural photosensitizers are more prevalent in coastal waters than the open ocean, these results...

72

Solidification microstructure affecting ductility in semi-solid-cast products  

Microsoft Academic Search

The semi-solid process produces globular instead of dendritic alpha phase and extraordinarily fine fibrous aluminum–silicon eutectic structure, which apparently enables exceptionally high ductility, even when casting copper-containing and secondary alloys that would normally have limited ductility. Contrary to the experience with liquid cast products of the same alloys, semi-solid products can be given a T-5 heat treatment without loss of

J. L. Jorstad; Q. Y. Pan; D. Apelian

2005-01-01

73

Factors Affecting the Rate of Lactate Production in Rat Lens  

Microsoft Academic Search

The rate of lactate production from various glycolytic intermediates was tested with a dispersed lens incubating system. Conditions required to establish maximal linear activity (lactate production vs. time) in each case was examined. It was confirmed that under noninhibitory concentrations of ATP, hexokinase paced glycolysis. At pH 7.05, the glycolytic rate was 40% of that at pH 7.43 (37.5°C); pH

Hong-Ming Cheng

1977-01-01

74

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

75

Split torque transmission load sharing  

NASA Astrophysics Data System (ADS)

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.

1992-10-01

76

Personal and Institutional Characteristics Affecting Research Productivity of Academic Accountants  

Microsoft Academic Search

Accounting research and publication have taken on a role far beyond the advancement and dissemination of knowledge. Academics and institutions now focus on publications in major journals for funding, prestige, merit, and tenure decisions.This article attempts to identify institutional and individual variables that correlate with accounting research productivity. The results could benefit new PhDs, current faculty, and institutions wishing to

Alan S. Levitan; Russ Ray

1992-01-01

77

Running Torque of Ball Bearings with Polymer Lubricant (Effect of the Enclosure Form of Polymer Lubricant)  

Microsoft Academic Search

This article deals with the running torque of ball bearings with polymer lubricant (solid composite material composed of plastic impregnated with a large amount of oil or grease). The results of the experiment showed that the measured running torque of ball bearings with polymer lubricant was affected by the enclosure form of the polymer lubricant. With regard to ball bearings

HIROYUKI OHTA; MASAYUKI KANATSU

2005-01-01

78

The FRIABLE1 Gene Product Affects Cell Adhesion in Arabidopsis  

PubMed Central

Cell adhesion in plants is mediated predominantly by pectins, a group of complex cell wall associated polysaccharides. An Arabidopsis mutant, friable1 (frb1), was identified through a screen of T-DNA insertion lines that exhibited defective cell adhesion. Interestingly, the frb1 plants displayed both cell and organ dissociations and also ectopic defects in organ separation. The FRB1 gene encodes a Golgi-localized, plant specific protein with only weak sequence similarities to known proteins (DUF246). Unlike other cell adhesion deficient mutants, frb1 mutants do not have reduced levels of adhesion related cell wall polymers, such as pectins. Instead, FRB1 affects the abundance of galactose- and arabinose-containing oligosaccharides in the Golgi. Furthermore, frb1 mutants displayed alteration in pectin methylesterification, cell wall associated extensins and xyloglucan microstructure. We propose that abnormal FRB1 action has pleiotropic consequences on wall architecture, affecting both the extensin and pectin matrices, with consequent changes to the biomechanical properties of the wall and middle lamella, thereby influencing cell-cell adhesion. PMID:22916179

Neumetzler, Lutz; Humphrey, Tania; Lumba, Shelley; Snyder, Stephen; Yeats, Trevor H.; Usadel, Bjorn; Vasilevski, Aleksandar; Patel, Jignasha; Rose, Jocelyn K. C.; Persson, Staffan; Bonetta, Dario

2012-01-01

79

Bacterial Community Affects Toxin Production by Gymnodinium catenatum  

PubMed Central

The paralytic shellfish toxin (PST)-producing dinoflagellate Gymnodinium catenatum grows in association with a complex marine bacterial community that is both essential for growth and can alter culture growth dynamics. Using a bacterial community replacement approach, we examined the intracellular PST content, production rate, and profile of G. catenatum cultures grown with bacterial communities of differing complexity and composition. Clonal offspring were established from surface-sterilized resting cysts (produced by sexual crosses of strain GCDE06 and strain GCLV01) and grown with: 1) complex bacterial communities derived from each of the two parent cultures; 2) simplified bacterial communities composed of the G. catenatum-associated bacteria Marinobacter sp. strain DG879 or Alcanivorax sp. strain DG881; 3) a complex bacterial community associated with an untreated, unsterilized sexual cross of the parents. Toxin content (STX-equivalent per cell) of clonal offspring (134–197 fmol STX cell?1) was similar to the parent cultures (169–206 fmol STX cell?1), however cultures grown with single bacterial types contained less toxin (134–146 fmol STX cell?1) than offspring or parent cultures grown with more complex mixed bacterial communities (152–176 fmol STX cell?1). Specific toxin production rate (fmol STX day?1) was strongly correlated with culture growth rate. Net toxin production rate (fmol STX cell?1 day?1) did not differ among treatments, however, mean net toxin production rate of offspring was 8-fold lower than the parent cultures, suggesting that completion of the sexual lifecycle in laboratory cultures leads to reduced toxin production. The PST profiles of offspring cultures were most similar to parent GCDE06 with the exception of cultures grown with Marinobacter sp. DG879 which produced higher proportions of dcGTX2+3 and GC1+2, and lower proportions of C1+2 and C3+4. Our data demonstrate that the bacterial community can alter intracellular STX production of dinoflagellates. In G. catenatum the mechanism appears likely to be due to bacterial effects on dinoflagellate physiology rather than bacterial biotransformation of PST toxins. PMID:25117053

Albinsson, Maria E.; Negri, Andrew P.; Blackburn, Susan I.; Bolch, Christopher J. S.

2014-01-01

80

Factors affecting pouring ready mix concrete production rate using tower cranes in Egypt  

Microsoft Academic Search

Poor productivity of construction industry is one of the causes of cost and time overruns in construction projects. The first stage to control this problem is to identify factors affecting productivity and analyse them in order to control their effect in productivity. In Egypt, construction productivity is influenced by several factors that vary from project to project as well as

Emad El-Maghraby; Jan Frick; Christopher Irgens

2011-01-01

81

Factors affecting the fermentative lactic acid production from renewable resources 1  

Microsoft Academic Search

Parameters affecting the fermentative lactic acid (LA) production are summarized and discussed: microorganism, carbon- and nitrogen-source, fermentation mode, pH, and temperature. LA production is compared in terms of LA concentration, LA yield and LA productivity. Also by-product formation and LA isomery are discussed.

Karin Hofvendahl

2000-01-01

82

Spin-torque building blocks  

NASA Astrophysics Data System (ADS)

The discovery of the spin-torque effect has made magnetic nanodevices realistic candidates for active elements of memory devices and applications. Magnetoresistive effects allow the read-out of increasingly small magnetic bits, and the spin torque provides an efficient tool to manipulate -- precisely, rapidly and at low energy cost -- the magnetic state, which is in turn the central information medium of spintronic devices. By keeping the same magnetic stack, but by tuning a device's shape and bias conditions, the spin torque can be engineered to build a variety of advanced magnetic nanodevices. Here we show that by assembling these nanodevices as building blocks with different functionalities, novel types of computing architecture can be envisaged. We focus in particular on recent concepts such as magnonics and spintronic neural networks.

Locatelli, N.; Cros, V.; Grollier, J.

2014-01-01

83

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

E-print Network

Herbivore and Fungal Pathogen Exclusion Affects the Seed Production of Four Common Grassland Exclusion Affects the Seed Production of Four Common Grassland Species. PLoS ONE 5(8): e12022. doi:10 and the colonization of large-scale disturbances [1,2]. Soil disturbance in the North American tallgrass prairie

Crews, Stephen

84

Factors Affecting the Production of Vietnamese Tones: A Study of American Learners  

ERIC Educational Resources Information Center

This study investigates factors that affect the accuracy of tone production by American students of Vietnamese as a second language (L2). Nine hypotheses are examined, each of which isolates a factor expected to affect production accuracy: (a) task type, (b) the position of a tone in a clause, (c) discourse distance between a model provided by a…

Nguyen, Hanh thi; Macken, Marlys A.

2008-01-01

85

Constructing a hybrid Kansei engineering system based on multiple affective responses: Application to product form design  

Microsoft Academic Search

This study proposes an expert system, which is called hybrid Kansei engineering system (HKES) based on multiple affective responses (MARs), to facilitate the development of product form design. HKES is consists of two sub-systems, namely forward Kansei engineering system (FKES) and backward Kansei engineering system (BKES). FKES is utilized to generate product alternatives and BKES is utilized to predict affective

Chih-Chieh Yang

2011-01-01

86

High torque miniature rotary actuator  

NASA Astrophysics Data System (ADS)

This paper summarizes the design and the development of a miniature rotary actuator (36 mm diameter by 100 mm length) used in spacecraft mechanisms requiring high torques and/or ultra-fine step resolution. This actuator lends itself to applications requiring high torque but with strict volume limitations which challenge the use of conventional rotary actuators. The design challenge was to develop a lightweight (less than 500 grams), very compact, high bandwidth, low power, thermally stable rotary actuator capable of producing torques in excess of 50 N.m and step resolutions as fine as 0.003 degrees. To achieve a relatively high torsional stiffness in excess of 1000 Nm/radian, the design utilizes a combination of harmonic drive and multistage planetary gearing. The unique design feature of this actuator that contributes to its light weight and extremely precise motion capability is a redundant stepper motor driving the output through a multistage reducing gearbox. The rotary actuator is powered by a high reliability space-rated stepper motor designed and constructed by Moog, Inc. The motor is a three-phase stepper motor of 15 degree step angle, producing twenty-four full steps per revolution. Since micro-stepping is not used in the design, and un-powered holding torque is exhibited at every commanded step, the rotary actuator is capable of reacting to torques as high as 35 Nm by holding position with the power off. The output is driven through a gear transmission having a total train ratio of 5120:1, resulting in a resolution of 0.003 degrees output rotation per motor step. The modular design of the multi-stage output transmission makes possible the addition of designs having different output parameters, such as lower torque and higher output speed capability. Some examples of an actuator family based on this growth capability will be presented in the paper.

Nalbandian, Ruben

2005-07-01

87

Bacterial biogas production in coastal systems affected by freshwater inputs  

NASA Astrophysics Data System (ADS)

The concentrations of two greenhouse gases, nitrous oxide (N 2O) and methane (CH 4), and the bacterial processes involved in their production (nitrification and denitrification for N 2O, and methanogenesis for CH 4), 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 Sea, and on the other part in the inner Thermaikos Gulf, in Aegean Sea, eastern Mediterranean Sea. High concentrations of dissolved CH 4 and N 2O were recorded in the surface waters of Gulf of Lions and Gulf of Thermaikos, up to 1300 nM for CH 4, and 40 nM for N 2O. No direct relationship could be found between the concentration and production of the biogases, as they may also be produced in deep water or bottom sediment in shallow areas, or derived from anthropogenic activity or ship contamination in polluted areas. Irrespective of the origin of CH 4 and N 2O, the presence of extremely high concentrations of these two gases in superficial seawater implies that they can easily escape to the atmosphere; consequently, these nearshore waters enriched in greenhouse gases may play an important role in the increase in atmospheric concentration of both CH 4 and N 2O.

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

2001-12-01

88

How hollow melanosomes affect iridescent colour production in birds  

PubMed Central

Developmental constraints and trade-offs can limit diversity, but organisms have repeatedly evolved morphological innovations that overcome these limits by expanding the range and functionality of traits. Iridescent colours in birds are commonly produced by melanin-containing organelles (melanosomes) organized into nanostructured arrays within feather barbules. Variation in array type (e.g. multilayers and photonic crystals, PCs) is known to have remarkable effects on plumage colour, but the optical consequences of variation in melanosome shape remain poorly understood. Here, we used a combination of spectrophotometric, experimental and theoretical methods to test how melanosome hollowness—a morphological innovation largely restricted to birds—affects feather colour. Optical analyses of hexagonal close-packed arrays of hollow melanosomes in two species, wild turkeys (Meleagris gallopavo) and violet-backed starlings (Cinnyricinclus leucogaster), indicated that they function as two-dimensional PCs. Incorporation of a larger dataset and optical modelling showed that, compared with solid melanosomes, hollow melanosomes allow birds to produce distinct colours with the same energetically favourable, close-packed configurations. These data suggest that a morphological novelty has, at least in part, allowed birds to achieve their vast morphological and colour diversity. PMID:23902909

Eliason, Chad M.; Bitton, Pierre-Paul; Shawkey, Matthew D.

2013-01-01

89

How hollow melanosomes affect iridescent colour production in birds.  

PubMed

Developmental constraints and trade-offs can limit diversity, but organisms have repeatedly evolved morphological innovations that overcome these limits by expanding the range and functionality of traits. Iridescent colours in birds are commonly produced by melanin-containing organelles (melanosomes) organized into nanostructured arrays within feather barbules. Variation in array type (e.g. multilayers and photonic crystals, PCs) is known to have remarkable effects on plumage colour, but the optical consequences of variation in melanosome shape remain poorly understood. Here, we used a combination of spectrophotometric, experimental and theoretical methods to test how melanosome hollowness--a morphological innovation largely restricted to birds--affects feather colour. Optical analyses of hexagonal close-packed arrays of hollow melanosomes in two species, wild turkeys (Meleagris gallopavo) and violet-backed starlings (Cinnyricinclus leucogaster), indicated that they function as two-dimensional PCs. Incorporation of a larger dataset and optical modelling showed that, compared with solid melanosomes, hollow melanosomes allow birds to produce distinct colours with the same energetically favourable, close-packed configurations. These data suggest that a morphological novelty has, at least in part, allowed birds to achieve their vast morphological and colour diversity. PMID:23902909

Eliason, Chad M; Bitton, Pierre-Paul; Shawkey, Matthew D

2013-09-22

90

DTC Based Induction Motor Speed Control Using 10-Sector Methodology for Torque Ripple Reduction  

NASA Astrophysics Data System (ADS)

A direct torque control (DTC) drive allows direct and independent control of flux linkage and electromagnetic torque by the selection of optimum inverter switching modes. It is a simple method of signal processing which gives excellent dynamic performance. Also transformation of coordinates and voltage decoupling are not required. However, the possible discrete inverter switching vectors cannot always generate exact stator voltage required, to obtain the demanded electromagnetic torque and flux linkages. This results in the production of ripples in the torque as well as flux waveforms. In the present paper a torque ripple reduction methodology is proposed. In this method the circular locus of flux phasor is divided into 10 sector as compared to six sector divisions in conventional DTC method. The basic DTC scheme and the 10-sector method are simulated and compared for their performance. An analysis is done with sector increment so that finally the torque ripple varies slightly as the sector is increased.

Pavithra, S.; Dinesh Krishna, A. S.; Shridharan, S.

2014-09-01

91

Firing of antagonist small-diameter muscle afferents reduces voluntary activation and torque of elbow flexors  

PubMed Central

During muscle fatigue, firing of small-diameter muscle afferents can decrease voluntary activation of the fatigued muscle. However, these afferents may have a more widespread effect on other muscles in the exercising limb. We examined if the firing of fatigue-sensitive afferents from elbow extensor muscles in the same arm reduces torque production and voluntary activation of elbow flexors. In nine subjects we examined voluntary activation of elbow flexors by measuring changes in superimposed twitches evoked by transcranial magnetic stimulation of the motor cortex during brief (2–3 s) maximal voluntary contractions (MVC). Inflation of a blood pressure cuff following a 2-min sustained MVC blocked blood flow to the fatigued muscle and maintained firing of small-diameter afferents. After a fatiguing elbow flexion contraction, maximal flexion torque was lower (26.0 ± 4.4%versus 67.9 ± 5.2% of initial maximal torque; means ±s.d.; P < 0.001) and superimposed twitches were larger (4.1 ± 1.1%versus 1.8 ± 0.2% ongoing MVC, P= 0.01) with than without ischaemia. After a fatiguing elbow extensor contraction, maximal flexion torque was also reduced (82.2 ± 4.9%versus 91.4 ± 2.3% of initial maximal torque; P= 0.007), superimposed twitches were larger (2.7 ± 0.7%versus 1.3 ± 0.2% ongoing MVC; P= 0.02) and voluntary activation lower (81.6 ± 8.2%versus 95.5 ± 6.9%; P= 0.04) with than without ischaemia. After a fatiguing contraction, voluntary drive to the fatigued muscles is reduced with continued input from small-diameter muscle afferents. Furthermore, fatigue of the elbow extensor muscles decreases voluntary drive to unfatigued elbow flexors of the same arm. Therefore, firing of small-diameter muscle afferents from one muscle can affect voluntary activation and hence torque generation of another muscle in the same limb. PMID:23652589

Kennedy, David S; McNeil, Chris J; Gandevia, Simon C; Taylor, Janet L

2013-01-01

92

Environmental and genetic factors affecting udder characters and milk production in Chios sheep  

E-print Network

Environmental and genetic factors affecting udder characters and milk production in Chios sheep A environmental and genetic factors influencing udder characteristics and milk production in Chios sheep. All. Seasonal effects were significant for udder circumference, test-day milk and total milk production

Paris-Sud XI, Université de

93

A MULTI-YEAR STUDY OF FACTORS AFFECTING FRUIT PRODUCTION IN ARISTOLOCHIA PAUCINERVIS  

E-print Network

A MULTI-YEAR STUDY OF FACTORS AFFECTING FRUIT PRODUCTION IN ARISTOLOCHIA PAUCINERVIS-pollination seems to be a decisive factor in fruit production because the number of germinated pollen and the fruit can be the first factor limiting fruit production (Schemske, 1980; Howell and Roth, 1981; Arista et al

Herrera, Carlos M.

94

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

95

2004-01-1370 Observer Design for Torque Balancing on a DI Engine  

E-print Network

a bias in injected masses between cylinders (relative errors can be up to 20%). Torque production is a monotonic function of the fuel mass injected into each cylinder. · This torque variation is thus a periodic of injected fuel and to the burning velocity)[1]. This model includes combustion and a transformation

96

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

97

CO2, nitrogen, and diversity differentially affect seed production of prairie plants.  

PubMed

Plant species composition and diversity is often influenced by early life history stages; thus, global change could dramatically affect plant community structure by altering seed production. Unfortunately, plant reproductive responses to global change are rarely studied in field settings, making it difficult to assess this possibility. To address this issue, we quantified the effects of elevated CO2, nitrogen deposition, and declining diversity on inflorescence production and inflorescence mass of 11 perennial grassland species in central Minnesota, U.S.A. We analyzed these data to ask whether (1) global change differentially affects seed production of co-occurring species; (2) seed production responses to global change are similar for species within the same functional group (defined by ecophysiology and growth form); and (3) seed production responses to global change match productivity responses: We found that, on average, allocation to seed production decreased under elevated CO2, although individual species responses were rarely significant due to low power (CO2 treatment df = 2). The effects of nitrogen deposition on seed production were similar within functional groups: C4 grasses tended to increase while C3 grasses tended to decrease allocation to seed production. Responses to nitrogen deposition were negatively correlated to productivity responses, suggesting a trade-off. Allocation to seed production of some species responded to a diversity gradient, but responses were uncorrelated to productivity responses and not similar within functional groups. Presumably, species richness has complex effects on the biotic and abiotic variables that influence seed production. In total, our results suggest that seed production of co-occurring species will be altered by global change, which may affect plant communities in unpredictable ways. Although functional groups could be used to generalize seed production responses to nitrogen deposition in Minnesota prairies, we caution against relying on them for predictive purposes without a mechanistic understanding of how resource availability and biotic interactions affect seed production. PMID:19694130

HilleRisLambers, J; Harpole, W S; Schnitzer, S; Tilman, D; Reich, P B

2009-07-01

98

Pearl millet: parboiling methods and factors affecting the process and cooked product  

E-print Network

PEARL MILLET: PARBOILING METHODS AND FACTORS AFFECTING THE PROCESS AND COOKED PRODUCT A Thesis by CHALLY JOEL CLEGG Submitted to the Office of Graduate Studies Texas A8 M University in partial fulfillment of the requirements for the degree... of MASTER OF SCIENCE August 1991 Major Subject: Food Science and Technology PEARL MILLET: PARBOILING METHODS AND FACTORS AFFECTING THE PROCESS AND COOKED PRODUCT A Thesis by CHALLY JOEL CLEGG Approved as to style and content by: LI d W. Roon...

Clegg, Chally Joel

2012-06-07

99

Factors affecting the cooking and extrusion properties of sorghum for noodle production  

E-print Network

FACTORS AFFECTING THE COOKING AND EXTRUSION PROPERTIES OF SORGHUM FOR NOODLE PRODUCTION A Thesis by ROSEMARY IKALAFENG LEKALAKE Submitted to the Office of Graduate Studies of Texas A&M University in partial fulfillment of the requirements... for the degree of MASTER OF SCIENCE August 1993 Major Subject: Food Science and Technology FACTORS AFFECTING THE COOKING AND EXTRUSION PROPERTIES OF SORGHUM FOR NOODLE PRODUCTION A Thesis by ROSEMARy IKALAFENG LEKALAKE Approved as to style and content by...

Lekalake, Rosemary Ikalafeng

2012-06-07

100

Trophoblast Production of a Weakly Bioactive Human Chorionic Gonadotropin in Trisomy 21-Affected Pregnancy  

E-print Network

CG, are of placental origin. When the fetus is trisomy 21-affected, it is now well established that total human1 Trophoblast Production of a Weakly Bioactive Human Chorionic Gonadotropin in Trisomy 21-Affected Endocrinol Metab 02/2004; 89(2): 727-32 #12;2 ABSTRACT Total human chorionic gonadotropin (hCG) is high

Paris-Sud XI, Université de

101

Relation between torque history, firing frequency, decruitment levels and force balance in two flexors of the elbow.  

PubMed

By means of intramuscular electromyographic recordings, we studied the firing frequencies and recruitment/decruitment thresholds of individual motor units in two elbow flexors, the biarticular biceps brachii muscle and the monoarticular brachioradialis muscle. Subjects had to perform isometric contractions with increasing elbow flexion torque until a specific peak torque level was reached. The torque level was kept constant for 6 s during which firing frequencies were measured. Then the torque was decreased to a lower level and, after 3 s, firing frequencies were again measured for 6 s. By repeating this procedure, the torque level was decreased stepwise until the motor unit under study stopped firing. The last level before the unit stopped firing was considered to be the decruitment torque level. We measured the firing frequency at recruitment and decruitment, the torque-frequency relationship and the recruitment and decruitment torque thresholds after various levels of peak torque. In the biceps, both the firing frequencies at a specific torque level and the decruitment torque level itself were independent of the peak torque. In the brachioradialis, however, firing frequencies at a specific torque level decreased and decruitment torque levels increased after subjects generated higher peak torques. Thus, in this muscle firing frequencies as well as decruitment thresholds show hysteresis effects. The result indicates a shift of force from the brachioradialis muscle during recruitment to the biceps muscle during decruitment. This shift is smaller than was concluded from previous studies in which decruitment threshold levels for the brachioradialis muscle were assumed to be independent of force history. Moreover, we found that in both muscles decruitment firing frequencies were lower than recruitment frequencies and they were independent of the peak torque level. In order to analyse the effect of the peak torque level on the distribution of force over the two muscles, we performed a model study in which we simulated the activation-frequency relation of two elbow flexors: a biceps-like and brachioradialis-like muscle, each contributing equally to the elbow torque during recruitment. In addition, we analysed how the different behaviour of the biceps and the brachioradialis during decruitment alters their contribution to the total torque production and how this redistribution is caused. The model study shows that the shift in contribution to the total torque is not constant during the relaxation phase and is not caused by a simple mechanism like a shift of activation from one muscle to another. Furthermore, changes limited to the muscle in which hysteresis is present do not seem to be sufficient to explain the experimental results. PMID:10638433

van Groeningen, C J; Nijhof, E J; Vermeule, F M; Erkelens, C J

1999-12-01

102

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

Code of Federal Regulations, 2012 CFR

...continuous compliance with the emission limits for tire production affected sources? 63.6004...Standards for Hazardous Air Pollutants: Rubber Tire Manufacturing Continuous Compliance Requirements for Tire Production Affected Sources §...

2012-07-01

103

40 CFR 63.5986 - What emission limits must I meet for tire cord production affected sources?  

... false What emission limits must I meet for tire cord production affected sources? 63.5986...Standards for Hazardous Air Pollutants: Rubber Tire Manufacturing Emission Limits for Tire Cord Production Affected Sources §...

2014-07-01

104

40 CFR Table 7 to Subpart Xxxx of... - Initial Compliance With the Emission Limits for Tire Cord Production Affected Sources  

...Compliance With the Emission Limits for Tire Cord Production Affected Sources 7 ...Standards for Hazardous Air Pollutants: Rubber Tire Manufacturing Pt. 63, Subpt. XXXX...Compliance With the Emission Limits for Tire Cord Production Affected Sources...

2014-07-01

105

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

Code of Federal Regulations, 2010 CFR

...Compliance With the Emission Limits for Tire Production Affected Sources 6 Table...Standards for Hazardous Air Pollutants: Rubber Tire Manufacturing Pt. 63, Subpt. XXXX...Compliance With the Emission Limits for Tire Production Affected Sources As...

2010-07-01

106

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

...alternatives for meeting the emission limits for tire cord production affected sources? 63.5987...Standards for Hazardous Air Pollutants: Rubber Tire Manufacturing Emission Limits for Tire Cord Production Affected Sources §...

2013-07-01

107

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

...Compliance With the Emission Limits for Tire Production Affected Sources 6 Table...Standards for Hazardous Air Pollutants: Rubber Tire Manufacturing Pt. 63, Subpt. XXXX...Compliance With the Emission Limits for Tire Production Affected Sources As...

2013-07-01

108

40 CFR Table 7 to Subpart Xxxx of... - Initial Compliance With the Emission Limits for Tire Cord Production Affected Sources  

Code of Federal Regulations, 2012 CFR

...Compliance With the Emission Limits for Tire Cord Production Affected Sources 7 ...Standards for Hazardous Air Pollutants: Rubber Tire Manufacturing Pt. 63, Subpt. XXXX...Compliance With the Emission Limits for Tire Cord Production Affected Sources...

2012-07-01

109

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

...alternatives for meeting the emission limits for tire cord production affected sources? 63.5987...Standards for Hazardous Air Pollutants: Rubber Tire Manufacturing Emission Limits for Tire Cord Production Affected Sources §...

2014-07-01

110

40 CFR 63.5996 - How do I demonstrate initial compliance with the emission limits for tire production affected...  

Code of Federal Regulations, 2012 CFR

...compliance with the emission limits for tire production affected sources? 63.5996...Standards for Hazardous Air Pollutants: Rubber Tire Manufacturing Testing and Initial Compliance Requirements for Tire Production Affected Sources §...

2012-07-01

111

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

Code of Federal Regulations, 2011 CFR

...Compliance With the Emission Limits for Tire Cord Production Affected Sources 12...Standards for Hazardous Air Pollutants: Rubber Tire Manufacturing Pt. 63, Subpt. XXXX...Compliance With the Emission Limits for Tire Cord Production Affected Sources...

2011-07-01

112

40 CFR 63.5985 - What are my alternatives for meeting the emission limits for tire production affected sources?  

Code of Federal Regulations, 2013 CFR

...alternatives for meeting the emission limits for tire production affected sources? 63.5985 Section...Standards for Hazardous Air Pollutants: Rubber Tire Manufacturing Emission Limits for Tire Production Affected Sources § 63.5985...

2013-07-01

113

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

...continuous compliance with the emission limits for tire production affected sources? 63.6004...Standards for Hazardous Air Pollutants: Rubber Tire Manufacturing Continuous Compliance Requirements for Tire Production Affected Sources §...

2014-07-01

114

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

Code of Federal Regulations, 2010 CFR

...continuous compliance with the emission limits for tire production affected sources? 63.6004...Standards for Hazardous Air Pollutants: Rubber Tire Manufacturing Continuous Compliance Requirements for Tire Production Affected Sources §...

2010-07-01

115

40 CFR 63.5985 - What are my alternatives for meeting the emission limits for tire production affected sources?  

...alternatives for meeting the emission limits for tire production affected sources? 63.5985 Section...Standards for Hazardous Air Pollutants: Rubber Tire Manufacturing Emission Limits for Tire Production Affected Sources § 63.5985...

2014-07-01

116

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

...Compliance With the Emission Limits for Tire Cord Production Affected Sources 12...Standards for Hazardous Air Pollutants: Rubber Tire Manufacturing Pt. 63, Subpt. XXXX...Compliance With the Emission Limits for Tire Cord Production Affected Sources...

2010-07-01

117

40 CFR 63.5986 - What emission limits must I meet for tire cord production affected sources?  

Code of Federal Regulations, 2013 CFR

... true What emission limits must I meet for tire cord production affected sources? 63.5986...Standards for Hazardous Air Pollutants: Rubber Tire Manufacturing Emission Limits for Tire Cord Production Affected Sources §...

2013-07-01

118

40 CFR 63.5986 - What emission limits must I meet for tire cord production affected sources?  

Code of Federal Regulations, 2012 CFR

... false What emission limits must I meet for tire cord production affected sources? 63.5986...Standards for Hazardous Air Pollutants: Rubber Tire Manufacturing Emission Limits for Tire Cord Production Affected Sources §...

2012-07-01

119

40 CFR 63.5996 - How do I demonstrate initial compliance with the emission limits for tire production affected...  

Code of Federal Regulations, 2011 CFR

...compliance with the emission limits for tire production affected sources? 63.5996...Standards for Hazardous Air Pollutants: Rubber Tire Manufacturing Testing and Initial Compliance Requirements for Tire Production Affected Sources §...

2011-07-01

120

40 CFR 63.5985 - What are my alternatives for meeting the emission limits for tire production affected sources?  

Code of Federal Regulations, 2012 CFR

...alternatives for meeting the emission limits for tire production affected sources? 63.5985 Section...Standards for Hazardous Air Pollutants: Rubber Tire Manufacturing Emission Limits for Tire Production Affected Sources § 63.5985...

2012-07-01

121

40 CFR 63.5985 - What are my alternatives for meeting the emission limits for tire production affected sources?  

Code of Federal Regulations, 2010 CFR

...alternatives for meeting the emission limits for tire production affected sources? 63.5985 Section...Standards for Hazardous Air Pollutants: Rubber Tire Manufacturing Emission Limits for Tire Production Affected Sources § 63.5985...

2010-07-01

122

40 CFR 63.5996 - How do I demonstrate initial compliance with the emission limits for tire production affected...  

Code of Federal Regulations, 2013 CFR

...compliance with the emission limits for tire production affected sources? 63.5996...Standards for Hazardous Air Pollutants: Rubber Tire Manufacturing Testing and Initial Compliance Requirements for Tire Production Affected Sources §...

2013-07-01

123

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

Code of Federal Regulations, 2010 CFR

...alternatives for meeting the emission limits for tire cord production affected sources? 63.5987...Standards for Hazardous Air Pollutants: Rubber Tire Manufacturing Emission Limits for Tire Cord Production Affected Sources §...

2010-07-01

124

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

...Compliance With the Emission Limits for Tire Cord Production Affected Sources 12...Standards for Hazardous Air Pollutants: Rubber Tire Manufacturing Pt. 63, Subpt. XXXX...Compliance With the Emission Limits for Tire Cord Production Affected Sources...

2013-07-01

125

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

Code of Federal Regulations, 2011 CFR

...Compliance With the Emission Limits for Tire Production Affected Sources 6 Table...Standards for Hazardous Air Pollutants: Rubber Tire Manufacturing Pt. 63, Subpt. XXXX...Compliance With the Emission Limits for Tire Production Affected Sources As...

2011-07-01

126

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

Code of Federal Regulations, 2012 CFR

...Compliance With the Emission Limits for Tire Production Affected Sources 6 Table...Standards for Hazardous Air Pollutants: Rubber Tire Manufacturing Pt. 63, Subpt. XXXX...Compliance With the Emission Limits for Tire Production Affected Sources As...

2012-07-01

127

40 CFR Table 7 to Subpart Xxxx of... - Initial Compliance With the Emission Limits for Tire Cord Production Affected Sources  

Code of Federal Regulations, 2013 CFR

...Compliance With the Emission Limits for Tire Cord Production Affected Sources 7 ...Standards for Hazardous Air Pollutants: Rubber Tire Manufacturing Pt. 63, Subpt. XXXX...Compliance With the Emission Limits for Tire Cord Production Affected Sources...

2013-07-01

128

40 CFR 63.5985 - What are my alternatives for meeting the emission limits for tire production affected sources?  

Code of Federal Regulations, 2011 CFR

...alternatives for meeting the emission limits for tire production affected sources? 63.5985 Section...Standards for Hazardous Air Pollutants: Rubber Tire Manufacturing Emission Limits for Tire Production Affected Sources § 63.5985...

2011-07-01

129

40 CFR 63.5986 - What emission limits must I meet for tire cord production affected sources?  

Code of Federal Regulations, 2011 CFR

... true What emission limits must I meet for tire cord production affected sources? 63.5986...Standards for Hazardous Air Pollutants: Rubber Tire Manufacturing Emission Limits for Tire Cord Production Affected Sources §...

2011-07-01

130

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

Code of Federal Regulations, 2012 CFR

...alternatives for meeting the emission limits for tire cord production affected sources? 63.5987...Standards for Hazardous Air Pollutants: Rubber Tire Manufacturing Emission Limits for Tire Cord Production Affected Sources §...

2012-07-01

131

40 CFR Table 7 to Subpart Xxxx of... - Initial Compliance With the Emission Limits for Tire Cord Production Affected Sources  

Code of Federal Regulations, 2010 CFR

...Compliance With the Emission Limits for Tire Cord Production Affected Sources 7 ...Standards for Hazardous Air Pollutants: Rubber Tire Manufacturing Pt. 63, Subpt. XXXX...Compliance With the Emission Limits for Tire Cord Production Affected Sources...

2010-07-01

132

40 CFR 63.5986 - What emission limits must I meet for tire cord production affected sources?  

Code of Federal Regulations, 2010 CFR

... true What emission limits must I meet for tire cord production affected sources? 63.5986...Standards for Hazardous Air Pollutants: Rubber Tire Manufacturing Emission Limits for Tire Cord Production Affected Sources §...

2010-07-01

133

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

...Compliance With the Emission Limits for Tire Cord Production Affected Sources 12...Standards for Hazardous Air Pollutants: Rubber Tire Manufacturing Pt. 63, Subpt. XXXX...Compliance With the Emission Limits for Tire Cord Production Affected Sources...

2014-07-01

134

40 CFR 63.5996 - How do I demonstrate initial compliance with the emission limits for tire production affected...  

Code of Federal Regulations, 2010 CFR

...compliance with the emission limits for tire production affected sources? 63.5996...Standards for Hazardous Air Pollutants: Rubber Tire Manufacturing Testing and Initial Compliance Requirements for Tire Production Affected Sources §...

2010-07-01

135

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

Code of Federal Regulations, 2012 CFR

...Compliance With the Emission Limits for Tire Cord Production Affected Sources 12...Standards for Hazardous Air Pollutants: Rubber Tire Manufacturing Pt. 63, Subpt. XXXX...Compliance With the Emission Limits for Tire Cord Production Affected Sources...

2012-07-01

136

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

Code of Federal Regulations, 2011 CFR

...continuous compliance with the emission limits for tire production affected sources? 63.6004...Standards for Hazardous Air Pollutants: Rubber Tire Manufacturing Continuous Compliance Requirements for Tire Production Affected Sources §...

2011-07-01

137

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

Code of Federal Regulations, 2011 CFR

...alternatives for meeting the emission limits for tire cord production affected sources? 63.5987...Standards for Hazardous Air Pollutants: Rubber Tire Manufacturing Emission Limits for Tire Cord Production Affected Sources §...

2011-07-01

138

40 CFR Table 7 to Subpart Xxxx of... - Initial Compliance With the Emission Limits for Tire Cord Production Affected Sources  

Code of Federal Regulations, 2011 CFR

...Compliance With the Emission Limits for Tire Cord Production Affected Sources 7 ...Standards for Hazardous Air Pollutants: Rubber Tire Manufacturing Pt. 63, Subpt. XXXX...Compliance With the Emission Limits for Tire Cord Production Affected Sources...

2011-07-01

139

40 CFR 63.5996 - How do I demonstrate initial compliance with the emission limits for tire production affected...  

...compliance with the emission limits for tire production affected sources? 63.5996...Standards for Hazardous Air Pollutants: Rubber Tire Manufacturing Testing and Initial Compliance Requirements for Tire Production Affected Sources §...

2014-07-01

140

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

Code of Federal Regulations, 2013 CFR

...continuous compliance with the emission limits for tire production affected sources? 63.6004...Standards for Hazardous Air Pollutants: Rubber Tire Manufacturing Continuous Compliance Requirements for Tire Production Affected Sources §...

2013-07-01

141

Reconstructing the intermittent dynamics of the torque in wind turbines  

E-print Network

We apply a framework introduced in the late nineties to analyze load measurements in off-shore wind energy converters (WEC). The framework is borrowed from statistical physics and properly adapted to the analysis of multivariate data comprising wind velocity, power production and torque measurements, taken at one single WEC. In particular, we assume that wind statistics drives the fluctuations of the torque produced in the wind turbine and show how to extract an evolution equation of the Langevin type for the torque driven by the wind velocity. It is known that the intermittent nature of the atmosphere, i.e. of the wind field, is transferred to the power production of a wind energy converter and consequently to the shaft torque. We show that the derived stochastic differential equation quantifies the dynamical coupling of the measured fluctuating properties as well as it reproduces the intermittency observed in the data. Finally, we discuss our approach in the light of turbine monitoring, a particular importa...

Lind, Pedro G; Peinke, Joachim

2014-01-01

142

Reconstructing the intermittent dynamics of the torque in wind turbines  

NASA Astrophysics Data System (ADS)

We apply a framework introduced in the late nineties to analyze load measurements in off-shore wind energy converters (WEC). The framework is borrowed from statistical physics and properly adapted to the analysis of multivariate data comprising wind velocity, power production and torque measurements, taken at one single WEC. In particular, we assume that wind statistics drives the fluctuations of the torque produced in the wind turbine and show how to extract an evolution equation of the Langevin type for the torque driven by the wind velocity. It is known that the intermittent nature of the atmosphere, i.e. of the wind field, is transferred to the power production of a wind energy converter and consequently to the shaft torque. We show that the derived stochastic differential equation quantifies the dynamical coupling of the measured fluctuating properties as well as it reproduces the intermittency observed in the data. Finally, we discuss our approach in the light of turbine monitoring, a particular important issue in off-shore wind farms.

Lind, Pedro G.; Wächter, Matthias; Peinke, Joachim

2014-06-01

143

Quantifying Magnetic Stellar Wind Torques  

NASA Astrophysics Data System (ADS)

In order to be able to understand the evolution of stellar spin rates and differential rotation, it is necessary to have a rigorous theory for predicting angular momentum loss via magnetic stellar winds that is applicable over a wide range of conditions. Based upon the results of multidimensional, numerical simulations and semi-analytic calculations, we present an improved formulation for predicting the stellar wind torque, which is valid for varying degrees of magnetization in the wind, as well as for stellar spin rates that range from the slow- to the fast-magnetic-rotator regimes.

Matt, Sean; MacGregor, K. B.; Pinsonneault, M. H.; Greene, T. P.

2011-01-01

144

Magnetic field control. [electromechanical torquing device  

NASA Technical Reports Server (NTRS)

A torque control for an electromechanical torquing device of a type where a variable clearance occurs between a rotor and field is described. A Hall effect device senses the field present, which would vary as a function of spacing between field and rotor. The output of the Hall effect device controls the power applied to the field so as to provide a well defined field and thus a controlled torque to the rotor which is well defined.

Haeussermann, W. (inventor)

1982-01-01

145

Production of arabitol from glycerol: strain screening and study of factors affecting production yield  

Microsoft Academic Search

Glycerol is a major by-product from biodiesel production, and developing new uses for glycerol is imperative to overall economics\\u000a and sustainability of the biodiesel industry. With the aim of producing xylitol and\\/or arabitol as the value-added products\\u000a from glycerol, 214 yeast strains, many osmotolerant, were first screened in this study. No strains were found to produce large\\u000a amounts of xylitol

Srujana Koganti; Tsung Min Kuo; Cletus P. Kurtzman; Nathan Smith; Lu-Kwang Ju

2011-01-01

146

Parameters affecting production and character of an extrusion texturized protein product from defatted glandless cottonseed meal  

E-print Network

for product and process development studies. Cottonseed, another of the world's major oilseed crops, has many favorable attributes which have long been recognized, but because sample material has been limited, product develop- ment also has been limited.... One will note from Table 4 that the average product temperature in head No. 8 was higher and in head No. 5 was lower than the circulating oil temperature. Table 4 also shows the obvious trend that as the circulating oil temper- ature increases...

Taranto, Michael Vincent

2012-06-07

147

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

148

Age-related relative increases in electromyography activity and torque according to the maximal capacity during upright standing  

Microsoft Academic Search

The aim of this study was to assess the relative torque (a percentage of the maximal capacity of torque production) at the\\u000a ankle joint in young and elderly adults during different postural tasks of increasing difficulty. Seven young (~22 years old)\\u000a and seven older (~80 years old) men took part in this investigation. Maximal agonist torque was estimated from resultant and\\u000a antagonist

Maxime BillotEmilie; Emilie M. Simoneau; Jacques Van Hoecke; Alain Martin

2010-01-01

149

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

150

Age-related relative increases in electromyography activity and torque according to the maximal capacity during upright standing.  

PubMed

The aim of this study was to assess the relative torque (a percentage of the maximal capacity of torque production) at the ankle joint in young and elderly adults during different postural tasks of increasing difficulty. Seven young (approximately 22 years old) and seven older (approximately 80 years old) men took part in this investigation. Maximal agonist torque was estimated from resultant and antagonist torques in both populations in plantar-flexion (PF) and dorsi-flexion (DF). The sum of PF and DF maximal agonist torques was considered as the maximal capacity of torque production. The centre of pressure (CoP) displacement was analysed during Normal Quiet Stance, Romberg and One Leg Balance. During maximal contractions and postural tasks, the electromyographic (EMG) activity was simultaneously recorded on the triceps surae and tibialis anterior muscles. We observed that the maximal capacity of torque production was negatively correlated with the CoP displacement, whatever the population and the postural tasks. The relative torque during all postural tasks was positively correlated with the CoP displacement in both populations. Moreover, older adults needed more EMG activity than young adults to produce the same torque. From this knowledge, one can assume that increasing strength in the muscles of the ankle joint may improve postural stability in older adults; this might have implications in the prevention of falls in elderly persons and in rehabilitation programs for elderly people who have already fallen. PMID:20213469

Billot, Maxime; Simoneau, Emilie M; Van Hoecke, Jacques; Martin, Alain

2010-07-01

151

Study on affecting factors of collaborative product development based on collaboration hierarchy model  

Microsoft Academic Search

Aiming at the levels of collaborative degree in web-based product development, a collaboration hierarchy model of this product\\u000a development is developed in this paper. Based on the model, the affecting factors on collaboration levels are analyzed systematically\\u000a from many aspects, such as technology, organization and business. A gap analysis method is studied in detail, and is applied\\u000a in a real

Xiaodong Zhang; Yingzi Li; Zhiqiang Zhang

2007-01-01

152

Magnetic torque maximization in a camera shutter module by the topology optimization  

Microsoft Academic Search

In recent years, there has been a stronger demand for the weight reduction of components of various portable electronic devices.\\u000a This work is motivated by the need to reduce the weight of a camera shutter module without much decreasing the torque generated\\u000a by its magnetic circuit. Because the camera shutter speed is most significantly affected by the torque, the magnitude

Jihun Kim; Kyung Ho Sun; Woochul Kim; Jae Eun Kim

2010-01-01

153

Explosive sport training and torque kinetics in children.  

PubMed

A high rate of force development (RFD) is often more important than maximal force in daily and sports activities. In children, resistance training has been shown to increase maximal force. It is unclear whether, or to what extent, can children improve RFD and force kinetics. For this study, we compared strength and force kinetics of boy gymnasts with those of untrained boys and untrained men. Eight boy gymnasts (age, 9.5 ± 1.2 y), 20 untrained boys (age, 10.1 ± 1.3 y), and 20 untrained men (age, 22.9 ± 4.4 y) performed maximal, explosive, isometric elbow flexions (EF) and knee flexions (KF). Peak torque (maximal voluntary contraction (MVC)), elapsed times to 10%-100% MVC, peak rate of torque development (RTDpk), and other kinetics parameters were determined. When gymnasts were compared with untrained boys, size-normalized EF MVC was 11%-20% higher, RTDpk was 32% higher, and times to 30% and 80% MVC were 16% and 55% shorter, respectively (p < 0.05). No corresponding differences were observed in KF. Furthermore, although the normalized EF MVC was 28% lower in gymnasts than in men (p < 0.001), their torque kinetics parameters were similar. These findings highlight the specificity of gymnastics training, which markedly elevated the torque kinetics of young, prepubertal boys to adult levels, but only moderately affected peak torque. It is suggested that neurologic adaptations, such as enhanced firing and activation rates or increased type II motor-unit recruitment, as well as changes in musculotendinous stiffness, could explain these findings. PMID:23980732

Dotan, Raffy; Mitchell, Cameron J; Cohen, Rotem; Gabriel, David; Klentrou, Panagiota; Falk, Bareket

2013-07-01

154

FACTORS AFFECTING THE FORMATION OF ORGANIC BY-PRODUCTS DURING WATER CHLORINATION  

E-print Network

FACTORS AFFECTING THE FORMATION OF ORGANIC BY-PRODUCTS DURING WATER CHLORINATION: A BENCH conditions in water treatment plants is a critical issue that should take into account the influence, 2001; Christman et al., 1983; Water, Air, and Soil Pollution 159: 357­371, 2004. C 2004 Kluwer Academic

Arhonditsis, George B.

155

Engendered Analysis of the Socioeconomic Factors Affecting Smallholder Dairy Productivity: Experience from Kenya  

Microsoft Academic Search

The existing gap between potential and actual milk yield in Kenyan dairy farming and the need to bridge it led to the formulation of this study. The objective was to determine the socioeconomic factors including the gender variable affecting smallholder dairy productivity. The aim of incorporating gender was to capture in detail the factors peculiar to male and female smallholder

J. M. Chengole; L. N. Kimenye; S. G. Mbogoh

2003-01-01

156

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

157

Indian ricegrass (Oryzopsis hymenoides) Germination affected by irrigation and bagging during seed production  

Microsoft Academic Search

Seed dormancy is the primary factor limiting stand establishment of Indian ricegrass [Oryzopsis hymenoides (Roem. & Schult.) Ricker] in rangeland reseedings in western North America. Our objective was to determine if irrigation or bagging of plants during seed production affected dormancy of two Indian ricegrass accessions, the cultivar Paloma and the experimental population PI 478833. Bagging of inflorescences for research

T. A. Jones; D. C. Nielson

1994-01-01

158

Opportunities to increasing dry season rice productivity in low temperature affected areas  

E-print Network

Opportunities to increasing dry season rice productivity in low temperature affected areas Sipaseuth a , J. Basnayake b,*, S. Fukai b , T.C. Farrell b , M. Senthonghae a , Sengkeo a , S. Phamixay March 2007 Abstract Rice is a major source of food for more than 2.7 billion people and planted

van Kessel, Chris

159

Analyzing the Laws, Regulations, and Policies Affecting FDA-Regulated Products  

E-print Network

Analyzing the Laws, Regulations, and Policies Affecting FDA-Regulated Products FDLI FOOD AND DRUG additional regulation. As part of the National Nanotechnol- ogy Initiative (NNI) in the United States, 26 federal agencies, including the Food and Drug Administration (FDA), contributed to the development

Kokkoli, Efie

160

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

161

Minimization of torque ripple in SRM drives  

Microsoft Academic Search

The torque pulsations in switched reluctance motors (SRMs) are relatively higher compared to sinusoidal machines due to the doubly salient structure of the motor. The magnetization pattern of the individual phases together with the T-i-? characteristics of the motor dictate the amount of torque ripple during operation. Both machine design and electronic control approaches have been used to minimize the

Iqbal Husain

2002-01-01

162

New Calculations of Stellar Wind Torques  

NASA Astrophysics Data System (ADS)

Using numerical simulations of magnetized stellar winds, we carry out a parameter study to find the dependence of the stellar wind torque on observable parameters. We find that the power-law dependencies of the torque on parameters is significantly different than what has been used in all spin evolution models to date.

Matt, Sean P.; Pudritz, Ralph E.

2009-02-01

163

Magnetic Tweezers for the Measurement of Twist and Torque  

E-print Network

1 Magnetic Tweezers for the Measurement of Twist and Torque Authors: Jan n.h.dekker@tudelft.nl Corresponding author: Nynke H. Dekker Keywords: magnetic tweezers, magnetic torque tweezers, freely-orbiting magnetic tweezers, twist, torque

Dekker, Nynke

164

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

165

Fixed Torque Dynamo and Motor Model  

NSDL National Science Digital Library

The Fixed Torque Dynamo and Motor Model solves the coupled differential equations for an electric motor driven by a dynamo (generator). The model can be used as to illustrate elementary instabilities or bifurcations discussed in courses about nonlinear oscillators and dynamical systems. When the dynamo is driven at constant torque, chaotic reversals of the generated current and of the angular rotation of the motor are observed. The main window displays the dynamo angular velocity ?1, motor angular velocity ?2 and current I time series and a second window displays the phase space. The stator current Is (A), torque T (Nâ¢m), and resistance R (ohm) are adjustable. The Fixed Torque Dynamo and Motor Model was created using the Easy Java Simulations (EJS) modeling tool. It is distributed as a ready-to-run (compiled) Java archive. Double click the ejs_chaos_FixedTorqueDynamoAndMotor.jar file to run the program if Java is installed.

Christian, Wolfgang

2011-11-23

166

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

167

RADIOACTIVE MATERIAL PACKAGING TORQUE REQUIREMENTS COMPLIANCE  

SciTech Connect

Shipping containers used to transport radioactive material (RAM) in commerce employ a variety of closure mechanisms. Often, these closure mechanisms require a specific amount of torque be applied to a bolt, nut or other threaded fastener. It is important that the required preload is achieved so that the package testing and analysis is not invalidated for the purpose of protecting the public. Torque compliance is a means of ensuring closure preload, is a major factor in accomplishing the package functions of confinement/containment, sub-criticality, and shielding. This paper will address the importance of applying proper torque to package closures, discuss torque value nomenclature, and present one methodology to ensure torque compliance is achieved.

Watkins, R.; Leduc, D.

2011-03-24

168

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. PMID:20142274

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

2010-01-01

169

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

170

Switching Torque Converter: Concept and Preliminary Implementation  

NASA Astrophysics Data System (ADS)

It is preferable to refrain from switching the torque in mechanical systems because the abrupt change tends to cause vibration and noise. However, such vibration can be beneficial if it is used to store mechanical energy. Moreover, torque switching operations at higher frequencies are becoming possible because of the recent advances in clutch devices. This paper describes a novel torque conversion mechanism based on torque switching operations. The fundamental principle of the mechanism is the reciprocal translation between the work to and from axles and the rotational energy of a flywheel. Clutches are used to intermittently connect or disconnect the axles with the flywheel; the output torque is controlled by changing the time ratio of the connection. By performing switching operations at a higher frequency, almost continuous torque conversion can be realized. A prototype was created using electrorheological fluid clutches, and it showed the potential for torque conversion. The performance of the prototype was also analyzed by numerical simulation; this showed that the prototype worked in accordance with the principle. Moreover, the potential capability of the principle was investigated using a numerical model and the results suggest that by improving the mechanical design, a considerable improvement in performance is possible.

Hirota, Koichi; Ikei, Yasushi

171

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

172

Casimir torque between corrugated metallic plates  

E-print Network

We consider two parallel corrugated plates and show that a Casimir torque arises when the corrugation directions are not aligned. We follow the scattering approach and calculate the Casimir energy up to second order in the corrugation amplitudes, taking into account nonspecular reflections, polarization mixing and the finite conductivity of the metals. We compare our results with the proximity force approximation, which overestimates the torque by a factor 2 when taking the conditions that optimize the effect. We argue that the Casimir torque could be measured for separation distances as large as 1 $\\mu{\\rm m}.$

Robson B. Rodrigues; Paulo A. Maia Neto; Astrid Lambrecht; Serge Reynaud

2007-10-30

173

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

174

Maternal costs in offspring production affect investment rules in joint rearing  

E-print Network

, not group augmentation, predicts helping in an obligate cooperatively breeding bird. Proceedings of the Royal Society B: Biological Sciences, 279, 3861–3869. Browning, L. E., Young, C. M., Savage, J. L., Russell, D. J. F., Barclay, H., Griffith, S. C... Maternal costs in offspring production affect investment rules in joint rearing James L. Savage1*, Andrew F. Russell2 & Rufus A. Johnstone1 1 Department of Zoology, University of Cambridge, Downing Street, Cambridge CB2 3EJ, U.K. 2 Centre...

Savage, James L.; Russell, Andrew F.; Johnstone, Rufus A.

2012-11-21

175

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

176

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

177

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

National Technical Information Service (NTIS)

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 tor...

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

1995-01-01

178

Turbulent Torques on Protoplanets in a Dead Zone  

E-print Network

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 two 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 $\\sim 0.3$ 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.

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

2007-02-20

179

Polyhydroxyalkanoate synthesis affects biosurfactant production and cell attachment to hydrocarbons in Pseudomonas sp. KA-08.  

PubMed

Stressful conditions prevailing in hydrocarbon-contaminated sites influence the diversity, distribution, and activities of microorganisms. Oil bioremediation agents should develop special characteristics to cope with these environments like surfactant production and cellular affinity to hydrocarbons. Additionally, polyhydroxyalkanoate (PHA) accumulation was proven to improve tolerance to stressful conditions. Pseudomonas sp. KA-08 was isolated from a chronic oil-contaminated environment, it is highly tolerant to xylene, and it is able to accumulate PHA and to produce surfactant compounds that lower the water surface tension (ST) as well as bioemulsifiers. In this work, we studied the effect of the capability to accumulate PHAs on biosurfactant production and microbial attachment to hydrocarbons (MATH). Our results showed that PHA synthesis capability has a favorable effect in the production of compounds which affect the ST but not on the production of bioemulsifiers. On the other hand, PHA accumulation affects cellular affinity to xylene. MATH analysis showed that a PHA-negative mutant increased its affinity to xylene compared with the wild-type strain. This result was also observed in Pseudomonas putida GPp104 (a PHA(-) mutant), suggesting that this effect could be generalized to other Pseudomonas strains. PMID:24519857

Di Martino, Carla; Catone, Mariela V; López, Nancy I; Raiger Iustman, Laura J

2014-06-01

180

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

181

Torque equilibrium attitude control for Skylab reentry  

NASA Technical Reports Server (NTRS)

All the available torque equilibrium attitudes (most were useless from the standpoint of lack of electrical power) and the equilibrium seeking method are presented, as well as the actual successful application during the 3 weeks prior to Skylab reentry.

Glaese, J. R.; Kennel, H. F.

1979-01-01

182

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

183

The Superrotation of Venus: Where's the Torque?  

E-print Network

The superrotation of the atmosphere of Venus requires a large torque on the up- per atmosphere. Mechanisms for providing a net balancing of this through waves or ionospheric motions to other parts of the atmosphere have been proposed but all have difficulties. Here we demonstrate that the albedo gradient from the day to night side of the cloud layer allows a gradient of light pressure that is sufficient to provide an external torque to drive this flow.

Chafin, Clifford

2014-01-01

184

Torque ripple minimization of doubly salient permanent-magnet motors  

Microsoft Academic Search

Due to the nature of salient poles in both the stator and rotor, the doubly salient permanent-magnet (DSPM) motor suffers from severe torque ripples. In this paper, the torque ripple of DSPM motors is analyzed, and the torque ripple factor is newly derived. A new approach, namely the conduction angle control, is proposed to minimize the torque ripple. Moreover, the

K. T. Chau; Qiang Sun; Ying Fan; Ming Cheng

2005-01-01

185

Direct torque control of induction machines using space vector modulation  

Microsoft Academic Search

A direct induction machine torque control method based on predictive, deadbeat control of the torque and flux is presented. By estimating the synchronous speed and the voltage behind the transient reactance, the change in torque and flux over the switching period is calculated. The stator voltage required to cause the torque and flux to be equal to their respective reference

Thomas G. Habetler; Francesco Profumo; Michele Pastorelli; Leon M. Tolbert

1992-01-01

186

Long-term changes in the production by estuarine macrobenthos affected by multiple stressors  

NASA Astrophysics Data System (ADS)

The macrobenthic production of an estuarine system was evaluated over a 14-year study period in a seagrass bed and in a sandflat. Over this period, the estuary suffered severe eutrophication and extreme weather events with important impacts on the community, impairing system functioning and ultimately the goods and services provided by the estuary (decline in the seagrass bed, decreased community production and/or a boost in the production by opportunist species, such as Hydrobia ulvae). Following the anthropogenic impacts, management measures were introduced which allowed a gradual recovery of the seagrass bed and a new macrobenthic community structure manifested by production increases of slow-growing species, such as Scrobicularia plana and Hediste diversicolor. There was a gradual re-orientation of energy into population biomass instead of population density but this was not translated into higher community production, mainly due to the decreased production of opportunist species ( H. ulvae and several polychaetes). Several weather extreme events occurred during this post-mitigation phase - floods, heatwaves and droughts, all of which had negative impacts on macrobenthic dynamics and production. The heatwaves led to the greatest decreases in macrobenthic production, mainly due to S. plana perhaps associated with its physiological intolerance of higher temperatures. The prolonged drought that followed the heatwaves maintained low levels of production by S. plana and H. ulvae. With climate change, the frequency and intensity of extreme weather events are likely to increase worldwide so that the recovery of impacted/disturbed systems from impacts such as eutrophication may be seriously affected by these additional stressors, compromising attempts to improve the ecological quality of estuarine ecosystems.

Dolbeth, M.; Cardoso, P. G.; Grilo, T. F.; Bordalo, M. D.; Raffaelli, D.; Pardal, M. A.

2011-03-01

187

Classical Torques on Gravity Probe B Gyroscopes  

NASA Astrophysics Data System (ADS)

Classical torques are a source of systematic error in Gravity Probe B experiment, so they were intensively studied throughout the whole program, which resulted in the detailed pre-flight Error Tree for each GP-B gyroscope. Extended classification of torques, their theory and examples are presented. Post-flight on-orbit calibrations showed unexpectedly large torque proportional to the spin-to-roll axis misalignment (proportionality up to ˜1 deg misalignment; misalignment through the science period within 50 arc-sec). The torque may be explained by a non-uniform distribution of electric potential over the rotor and housing surfaces (patch effect due to the micro-crystal structure, and/or dipole layer on the surface, etc.). A complete theory of the patch effect torque is established. It implies the corresponding signal model that allows one to separate the relativistic drift from the classical one and remove the effect of the latter, obtaining the desired accuracy of the relativistic drift rate determination. The most recent post-flight upper bound of the drift rate from all other classical torques is also given.

Silbergleit, Alex; Mac Keiser, G.; Ohshima, Yoshimi

2007-04-01

188

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. PMID:23405245

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

2013-01-01

189

A reactive torque control law for gyroscopically controlled space vehicles  

NASA Technical Reports Server (NTRS)

A method of control is developed based on the reactive torques as seen by the individual CMG gimbals. The application of a torque to the gimbal of a CMG rotates the momentum vector and applies a torque to the spacecraft according to well-known laws. The response (rotation) of the vehicle produces a reverse or reaction torque opposing the torque producing the gimbal movement. The reactive torque and the pseudoinverse control schemes are contrasted in order to point out the simplicity of the first method. Simulation was performed only to the extent necessary to prove that reactive torque stabilization and control is feasible.

Farmer, J. E.

1973-01-01

190

Dynamical corotation torques on low-mass planets  

E-print Network

We study torques on migrating low-mass planets in locally isothermal discs. Previous work on low-mass planets generally kept the planet on a fixed orbit, after which the torque on the planet was measured. In addition to these static torques, when the planet is allowed to migrate it experiences dynamical torques, which are proportional to the migration rate and whose sign depends on the background vortensity gradient. We show that in discs a few times more massive than the Minimum Mass Solar Nebula, these dynamical torques can have a profound impact on planet migration. Inward migration can be slowed down significantly, and if static torques lead to outward migration, dynamical torques can take over, taking the planet beyond zero-torque lines set by saturation of the corotation torque in a runaway fashion. This means the region in non-isothermal discs where outward migration is possible can be larger than what would be concluded from static torques alone.

Paardekooper, Sijme-Jan

2014-01-01

191

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

192

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

193

Intracolonial genetic variation affects reproductive skew and colony productivity during colony foundation in a parthenogenetic termite  

PubMed Central

Background In insect societies, intracolonial genetic variation is predicted to affect both colony efficiency and reproductive skew. However, because the effects of genetic variation on these two colony characteristics have been tested independently, it remains unclear whether they are affected by genetic variation independently or in a related manner. Here we test the effect of genetic variation on colony efficiency and reproductive skew in a rhinotermitid termite, Reticulitermes speratus, a species in which female-female pairs can facultatively found colonies. We established colonies using two types of female-female pairs: colonies founded by sisters (i.e., sister-pair colonies) and those founded by females from different colonies (i.e., unrelated-pair colonies). Colony growth and reproductive skew were then compared between the two types of incipient colonies. Results At 15 months after colony foundation, unrelated-pair colonies were larger than sister-pair colonies, although the caste ratio between workers and nymphs, which were alternatively differentiated from young larvae, did not differ significantly. Microsatellite DNA analyses of both founders and their parthenogenetically produced offspring indicated that, in both sister-pair and unrelated-pair colonies, there was no significant skew in the production of eggs, larvae, workers and soldiers. Nymph production, however, was significantly more skewed in the sister-pair colonies than in unrelated-pair colonies. Because nymphs can develop into winged adults (alates) or nymphoid reproductives, they have a higher chance of direct reproduction than workers in this species. Conclusions Our results support the idea that higher genetic variation among colony members could provide an increase in colony productivity, as shown in hymenopteran social insects. Moreover, this study suggests that low genetic variation (high relatedness) between founding females increases reproductive skew via one female preferentially channeling her relatives along the reproductive track. This study thus demonstrated that, in social insects, intracolonial genetic variation can simultaneously affect both colony efficiency and reproductive skew. PMID:25123355

2014-01-01

194

Effects of fatigue on the torque-velocity relation in muscle  

PubMed Central

Background: The extent to which fatigue is related to the velocity of shortening is still not fully understood. Objectives: To examine the effects of fatigue induced by maximal intensity exercise at different velocities on subsequent torque-velocity relations in muscle. Methods: Ten men (mean (SD) age 25 (3) years; stature 1.78 (0.34) m; body mass 80.6 (14.5) kg) provided written informed consent and, over a five day period in a randomised manner, performed 16 fatiguing bouts of maximal intensity exercise on an isokinetic dynamometer each followed by one repetition maximum action. Concentric peak torque of the preferred leg was assessed at angular velocities of 0.52, 1.05, 2.09, and 3.14 rad/s. Mechanical work performed for all fatiguing bouts was held at 3050–3150 J. After a 45 second rest, a maximum effort was performed at one of the preset velocities. As a baseline, dependent variables of peak torque (N.m), angle of peak torque (rad), and mean torque (N.m) were measured at each velocity. An analysis of covariance was used to compare torque-velocity relations, and one factor, within subject analyses of variance with repeated measures investigated differences from baseline. Results: Torque-velocity relations for all dependent variables did not differ (p>0.05). Similarly, angles at which peak torque occurred were not velocity dependent and did not differ from baseline and subsequent exercise measures (p>0.05). Generally, fatiguing exercise at low velocities led to reductions in peak and mean torque in subsequent exercise at higher velocities (p<0.05). Conclusions: Torque-velocity relations fundamentally remain intact after fatigue induced at any velocity, although the magnitude changes. The results suggest that the greater decline in torque during subsequent exercise at high velocities could be due to greater exhaustion of fatigue sensitive type II fibres, whereas low velocity subsequent exercise is less affected because of the greater use of type I fibres. PMID:12453837

Spendiff, O; Longford, N; Winter, E

2002-01-01

195

Does humor in radio advertising affect recognition of novel product brand names?  

PubMed

The authors proposed that item selection during shopping is based on brand name recognition rather than recall. College students rated advertisements and news stories of a simulated radio program for level of amusement (orienting activity) before participating in a surprise recognition test. Humor level of the advertisements was varied systematically, and content was controlled. According to signal detection analysis, humor did not affect the strength of recognition memory for brand names (nonsense units). However, brand names and product types were significantly more likely to be associated when appearing in humorous advertisements than in nonhumorous advertisements. The results are compared with prior findings concerning humor and recall. PMID:11506048

Berg, E M; Lippman, L G

2001-04-01

196

Two Penicillium camembertii mutants affected in the production of cyclopiazonic acid.  

PubMed Central

Penicillium camembertii was mutated and screened for cyclopiazonic acid-negative mutants. With a simple and rapid mini-extraction method for detection of cyclopiazonic acid production, we were able to isolate two strains which were affected in the production of this metabolite. One strain had completely lost the ability to synthesize detectable amounts of this secondary metabolite, whereas the other mutant produced 50 to 100 times less cyclopiazonic acid than the wild type. Also, the former strain had a changed morphology compared with the wild type. This morphological alteration appears to be coupled to the inability to produce cyclopiazonic acid because morphological revertants were able to synthesize cyclopiazonic acid to a level comparable to the wild type. The second mutant accumulated a new metabolite which was detectable by two-dimensional thin-layer chromatography. This new metabolite, however, appears not to be a direct precursor of cyclopiazonic acid. Images PMID:2268164

Geisen, R; Glenn, E; Leistner, L

1990-01-01

197

Numerical and Experimental Investigation of Roll Forces and Torques in Cold Roll Forming of a Channel Section  

NASA Astrophysics Data System (ADS)

One of the most important issues in the review of cold roll forming process of metals is estimation of force and torque. The optimum production line can be designed determining the effective parameters on force and torque. Some of these parameters are material, sheet thickness, bending angle, lubrication conditions, rolls rotational speed and distance of the stands. The aim of this study is to investigate the effect of thickness, yield strength, sheet width and forming angle plate on the force and torque applied on rolls. So the forming process was 3D simulated in finite element software Marc/mentat. Simulation results showed that with increase of yield strength, thickness and forming angle, applied force and torque on rolls will increase. Also the increase in sheet width- assuming constant flange length- will increase the force on the rolls and reduce the torque needed for forming. The effect of thickness and sheet width was experimentally investigated which verified the results obtained by FEA.

Davoodi, B.; Naeini, H. Moslemi; Asl, Y. Dadgar; Azizi T., R.; Kasaei, M. M.; Panahizadeh, V. R.

2011-01-01

198

Torque rheological parameters to predict pellet quality in extrusion-spheronization.  

PubMed

This study explored the feasibility of predicting the quality of microcrystalline cellulose (MCC) pellets prepared by extrusion-spheronization using torque rheological characterization. Rheological properties of eleven MCC grades as well as their binary mixtures with lactose (3:7) at various water contents were determined using a mixer torque rheometer (MTR). Derived torque parameters were: maximum torque and cumulative energy of mixing (CEM). CEM values of MCC powders (CEM((MCC))) could be attributed to their physical properties such as crystallinity, V(low P) and V(total) (volumes of mercury intruded in their pores at low pressure and the total intrusion volume), bulk and tapped densities. For both MCC powders and their binary mixtures, strong correlation was observed between their torque parameters and the properties of their pellets formed with 30 and 35% (w/w) water. Since this relationship was valid over a broad water content range, rheological assessment for pre-formulation purposes need not be performed at optimized water contents. These results demonstrated the usefulness of torque rheometry as an effective means of comparing and evaluating MCC grades especially when substitution of equivalent grades is encountered. In so doing, the tedious and expensive pre-production (pre-formulation and optimization) work can be considerably reduced. PMID:16574352

Soh, J L P; Liew, C V; Heng, P W S

2006-06-01

199

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

200

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

201

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. 5 figs.

King, R.D.; Doncker, R.W.A.A. De.; Szczesny, P.M.

1997-03-11

202

Photosynthesis, Productivity, and Yield of Maize Are Not Affected by Open-Air Elevation of CO2 Concentration in  

E-print Network

Photosynthesis, Productivity, and Yield of Maize Are Not Affected by Open-Air Elevation of CO2 that photosynthesis and production of maize may be unaffected by rising [CO2] in the absence of drought. This suggests that rising [CO2] may not provide the full dividend to North American maize production anticipated

Rogers, Alistair

203

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. PMID:21359137

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

2011-01-01

204

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

205

Thomas precession: Where is the torque  

SciTech Connect

Special relativity appears to violate the conservation of angular momentum {bold L} since it predicts that an accelerated gyroscope will precess, i.e., {bold L} will change in the absence of any applied torque. The paradox is resolved in a simple example by demonstrating that there is a torque present. The mass distribution in the gyroscope undergoes a relativistic distortion, and the center of mass is displaced away from the position of the accelerating force. The resulting torque {tau}={ital d}{bold L}/{ital dt}. The model also shows the physical origins of spin-orbit coupling and of the oscillating term.'' A related calculation shows why a moving magnetic dipole has an {ital electric} dipole moment.

Muller, R.A. (Department of Physics and Lawrence Berkeley Laboratory, University of California, Berkeley, California 94720 (United States))

1992-04-01

206

Torque for an Inertial Piezoelectric Rotary Motor  

PubMed Central

For a novel inertial piezoelectric rotary motor, the equation of the strain energy in the piezoceramic bimorph and the equations of the strain energy and the kinetic energy in the rotor are given. Based on them, the dynamic equation of the motor is obtained. Using these equations, the inertial driving torque of the motor is investigated. The results show that the impulsive driving torque changes with changing peak voltage of the excitation signal, the piezoelectric stress constant, the thickness of the piezoceramic bimorph, and the rotor radius obviously. Tests about the motor torque are completed which verifies the theory analysis here in. The results can be used to design the operating performance of the motor. PMID:24470794

Xing, Jichun

2013-01-01

207

Agent-patient similarity affects sentence structure in language production: evidence from subject omissions in Mandarin  

PubMed Central

Interference effects from semantically similar items are well-known in studies of single word production, where the presence of semantically similar distractor words slows picture naming. This article examines the consequences of this interference in sentence production and tests the hypothesis that in situations of high similarity-based interference, producers are more likely to omit one of the interfering elements than when there is low semantic similarity and thus low interference. This work investigated language production in Mandarin, which allows subject noun phrases to be omitted in discourse contexts in which the subject entity has been previously mentioned in the discourse. We hypothesize that Mandarin speakers omit the subject more often when the subject and the object entities are conceptually similar. A corpus analysis of simple transitive sentences found higher rates of subject omission when both the subject and object were animate (potentially yielding similarity-based interference) than when the subject was animate and object was inanimate. A second study manipulated subject-object animacy in a picture description task and replicated this result: participants omitted the animate subject more often when the object was also animate than when it was inanimate. These results suggest that similarity-based interference affects sentence forms, particularly when the agent of the action is mentioned in the sentence. Alternatives and mechanisms for this effect are discussed.

Hsiao, Yaling; Gao, Yannan; MacDonald, Maryellen C.

2014-01-01

208

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

209

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

Code of Federal Regulations, 2011 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 . . ....

2011-07-01

210

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

Code of Federal Regulations, 2010 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 . . ....

2010-07-01

211

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

Code of Federal Regulations, 2012 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 . . ....

2012-07-01

212

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

213

Achieving Consistent Maximum Brake Torque with Varied Injection Timing in a DI Diesel Engine  

E-print Network

The brake torque of a direct-injection diesel engine is known to plateau over a range of injection timings. Injection timing affects the engine’s ignition delay and the fractions of fuel which burn in premixed and diffusion modes. Therefore...

Kroeger, Timothy H

2013-09-19

214

Comparison of methods of minimization of cogging torque in wind generators using FE analysis  

Microsoft Academic Search

Most small wind turbines use permanent magnet (PM) generators. Small wind turbines are usually self-starting and require very simple controls. The cogging torque, which is generated by the interaction between the magnet- ized pole of PMs and the salient poles of the armature core, affects the self-start ability and results in undesirable mechanical vibrations and noises. Thus, minimization of cogging

AJAY KUMAR; SANJAY MARWAHA; ANUPMA MARWAHA

2006-01-01

215

Model Predictive Control of Velocity and Torque Split in a Parallel Hybrid Vehicle  

Microsoft Academic Search

Fuel economy of parallel hybrid electric vehicles is affected by both the torque split ratio and the vehicle velocity. To optimally schedule both variables, information about the surrounding traffic is necessary, but may be made available through telemetry. Consequently, in this paper, a nonlinear model predictive control algorithm is proposed for the vehicle control system to maximise fuel economy while

Tae Soo Kim; Chris Manzie; Rahul Sharma

2009-01-01

216

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. PMID:24759895

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

2014-01-01

217

New Simple Torque-Sensorless Torque Control for Quasi-Perfect Compensation of 6th Harmonic Torque Ripple Due to Nonsinusoidal Distribution of Back EMF of PMSM  

NASA Astrophysics Data System (ADS)

This paper proposes a new torque-sensorless torque control method for permanent-magnet synchronous motors (PMSMs). The proposed method can almost perfectly compensate the 6th harmonic torque ripple that is caused by the nonsinusoidal distributions of the back EMF and rotor magnetic flux of PMSMs. The torque control system is, in principle, constructed on the basis of the vector control, but has two new dedicated speed-varying devices—a harmonic torque observer and current controller. The speed-varying harmonic torque observer can estimate the harmonic component over a wide speed range, even in the case where the produced torque is constant, and generate a suitable compensating signal. The speed-varying current controller shows stable control performance over a wide speed range, it can fully track the compensated current command containing the dc and 6th harmonic components. The effectiveness of the proposed method is examined and verified through extensive numerical experiments.

Shinnaka, Shinji; Kishida, Hideo

218

MicroRNAs targeting Nicastrin regulate A? production and are affected by target site polymorphisms  

PubMed Central

Despite the growing number of genome-wide association studies, the involvement of polymorphisms in microRNA target sites (polymiRTS) in Alzheimer’s disease (AD) remains poorly investigated. Recently, we have shown that AD-associated single-nucleotide polymorphisms (SNPs) present in the 3? untranslated region (3?UTR) of amyloid precursor protein (APP) could directly affect miRNA function. In theory, loss of microRNA (miRNA) function could lead to risk for AD by increasing APP expression and A? peptide production. In this study, we tested the hypothesis that Nicastrin, a ?-secretase subunit involved in A? generation, could be regulated by miRNAs, and consequently affected by 3?UTR polymorphisms. Bioinformatic analysis identified 22 putative miRNA binding sites located in or near Nicastrin 3?UTR polymorphisms. From these miRNA candidates, six were previously shown to be expressed in human brain. We identified miR-24, miR-186, and miR-455 as regulators of Nicastrin expression, both in vitro and under physiological conditions in human cells, which resulted in altered A? secretion. Using luciferase-based assays, we further demonstrated that rs113810300 and rs141849450 SNPs affected miRNA-mediated repression of Nicastrin. Notably, rs141849450 completely abolished the miR-455-mediated repression of Nicastrin. Finally, the rs141849450 variant was identified in 1 out of 511 AD cases but not in 631 controls. These observations set the stage for future studies exploring the role of miRNAs and 3?UTR polymorphisms in AD. PMID:25100943

Delay, Charlotte; Dorval, Veronique; Fok, Alice; Grenier-Boley, Benjamin; Lambert, Jean-Charles; Hsiung, G.-Y.; Hebert, Sebastien S.

2014-01-01

219

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

220

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

221

Insecticide use in hybrid onion seed production affects pre- and postpollination processes.  

PubMed

Research on threats to pollination service in agro-ecosystems has focused primarily on the negative impacts of land use change and agricultural practices such as insecticide use on pollinator populations. Insecticide use could also affect the pollination process, through nonlethal impacts on pollinator attraction and postpollination processes such as pollen viability or pollen tube growth. Hybrid onion seed (Allium cepa L., Alliaceae) is an important pollinator-dependent crop that has suffered yield declines in California, concurrent with increased insecticide use. Field studies suggest that insecticide use reduces pollination service in this system. We conducted a field experiment manipulating insecticide use to examine the impacts of insecticides on 1) pollinator attraction, 2) pollen/stigma interactions, and 3) seed set and seed quality. Select insecticides had negative impacts on pollinator attraction and pollen/stigma interactions, with certain products dramatically reducing pollen germination and pollen tube growth. Decreased pollen germination was not associated with reduced seed set; however, reduced pollinator attraction was associated with lower seed set and seed quality, for one of the two female lines examined. Our results highlight the importance of pesticide effects on the pollination process. Overuse may lead to yield reductions through impacts on pollinator behavior and postpollination processes. Overall, in hybrid onion seed production, moderation in insecticide use is advised when controlling onion thrips, Thrips tabaci, on commercial fields. PMID:24665681

Gillespie, Sandra; Long, Rachael; Seitz, Nicola; Williams, Neal

2014-02-01

222

A Sensorless Direct Torque Control Scheme Suitable for Electric Vehicles  

E-print Network

a regenerative torque demand; the remaining pedal travel brings in a set of standard mechanical brakes. For EV of the maximum available torque. Similarly, the first portion of the brake pedal travel is used to derive

Paris-Sud XI, Université de

223

Torque wrench allows readings from inaccessible locations  

NASA Technical Reports Server (NTRS)

Torque wrench with an adjustable drive shaft permits indicator to remain in view when used on sections of equipment with limited access. The shaft is capable of protruding from either side of the wrench head by means of spring loaded balls.

De Barnardo, M.

1966-01-01

224

Radiative Torque Alignment: Essential Physical Processes  

NASA Astrophysics Data System (ADS)

Aligned grains provide a unique way to trace magnetic field topology in many astrophysical environments. In Lazarian & Hoang (2006), we derived analytical expressions for radiative torque (RAT) components, and studied the dynamics of grains assuming that the maximal inertia axis is always parallel to angular momentum. In this paper, to get insight into the dynamics of grains when thermal fluctuations are accounted for, we use AMO, and perform analytically averaging for RAT components. In addition, we study the RAT alignment for irregular grains (shape 1 and 3). We also evaluate the influence of suprathermal torques arising from H2 formation, as well as randomizing collisions with atomic gas on the alignment of grains driven by radiative torques (RATs). Our study is both based on the analytical model (AMO) and numerical calculations of RATs for irregular grains. To describe the H2 formation torques and random collisions we use the Langevin equation approach. We show that when thermal fluctuations are included, for both AMO and irregular grains, RATs tend to align grains at attractor points with low angular momentum (low-J attractor point). We found that random collisions by atomic gas act to substantially disalign the grain alignment in the case the phase trajectory map has only the low-J attractor point. In particular, if there exist attractor points at high angular momentum in the phase trajectory map, gas bombardment can move grains from the low- J attractor point to the high-J attractor point. Thus the degree of alignment increases.

Hoang, Thiem; Lazarian, A.

2007-05-01

225

A force and torque tensegrity sensor  

Microsoft Academic Search

Tensegrity structures represent a special class of flexible structures, whose members can simultaneously perform the functions of strength, sensing, actuating, and feedback control. In this article we show how these structures intrinsic properties can be exploited to construct a smart sensor for simultaneous measurement of six different quantities: three orthogonal forces and three orthogonal torques. The static and dynamic characteristics

Cornel Sultan; Robert Skelton

2004-01-01

226

High starting torque for AC SCR controller  

Microsoft Academic Search

A control strategy is proposed for AC thyristor controllers. The main feature of the proposed technique is that motors can start with high torque, while using an economical design. This allows the use of AC thyristor controllers for a wide range of applications, where they have not been used before. The method employs the AC thyristor controller as a discrete

Antonio Ginart; Rosana Esteller; A. Maduro; R. Piiiero; R. Moncada

1999-01-01

227

Cogging Torque Reduction in Permanent Magnet Machines  

Microsoft Academic Search

This paper examines two methods - magnet shifting and optimizing the magnet pole arc - for reducing cogging torque in permanent magnet machines. The methods were applied to existing machine designs and their performance was calculated using finite-element analysis (FEA). Prototypes of the machine designs were constructed and experimental results obtained. It is shown that the FEA predicted the cogging

Luke Dosiek; Pragasen Pillay

2007-01-01

228

Influence of electron-magnon scattering on spin transfer torque in magnetic tunnel junctions  

NASA Astrophysics Data System (ADS)

Manipulating the magnetization direction using spin transfer torque in magnetic tunnel junctions (MTJs) has been one of the most important challenges in spin electronics for the past five years. Elastic tunneling theories show that the torque possesses two components, one being mainly linear in bias voltage whereas the other shows a quadratic bias dependence. These theoretical results have been recently confirmed by ``spin-diode'' experiments [1]. However, the validity of the elastic tunneling has been questioned by two experimental studies [2]. These studies show that the bias dependence of the out-of-plane torque can be dramatically different from the elastic quadratic dependence. Using the Transfer Hamiltonian formalism, we study the influence of interfacial electron-magnon scattering on the bias dependence of the spin transfer torque. We show that this mechanism can strongly affect the bias dependence of the spin transfer torque, in agreement with the recent experimental studies [2]. [1] J. C. Sankey et al., Nature Physics 4, 67 (2008); H. Kubota et al., Nature Physics 4, 37 (2008). [2] S. Petit, et al., Phys. Rev. Lett. 98, 077203 (2007); Z. Li, et al., Phys. Rev. Lett. 100, 246602 (2008).

Manchon, Aurelien; Zhang, Shufeng

2009-03-01

229

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. PMID:22680910

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

2013-01-01

230

IL-27 affects helper T cell responses via regulation of PGE2 production by macrophages.  

PubMed

IL-27 is a heterodimeric cytokine that regulates both innate and adaptive immunity. The immunosuppressive effect of IL-27 largely depends on induction of IL-10-producing Tr1 cells. To date, however, effects of IL-27 on regulation of immune responses via mediators other than cytokines remain poorly understood. To address this issue, we examined immunoregulatory effects of conditional medium of bone marrow-derived macrophages (BMDMs) from WSX-1 (IL-27R?)-deficient mice and found enhanced IFN-? and IL-17A secretion by CD4(+) T cells as compared with that of control BMDMs. We then found that PGE2 production and COX-2 expression by BMDMs from WSX-1-deficient mice was increased compared to control macrophages in response to LPS. The enhanced production of IFN-? and IL-17A was abolished by EP2 and EP4 antagonists, demonstrating PGE2 was responsible for enhanced cytokine production. Murine WSX-1-expressing Raw264.7 cells (mWSX-1-Raw264.7) showed phosphorylation of both STAT1 and STAT3 in response to IL-27 and produced less amounts of PGE2 and COX-2 compared to parental RAW264.7 cells. STAT1 knockdown in parental RAW264.7 cells and STAT1-deficiency in BMDMs showed higher COX-2 expression than their respective control cells. Collectively, our result indicated that IL-27/WSX-1 regulated PGE2 secretion via STAT1-COX-2 pathway in macrophages and affected helper T cell response in a PGE2-mediated fashion. PMID:25088998

Sato, Yayoi; Hara, Hiromitsu; Okuno, Toshiaki; Ozaki, Naoko; Suzuki, Shinobu; Yokomizo, Takehiko; Kaisho, Tsuneyasu; Yoshida, Hiroki

2014-08-22

231

Conservation of Angular-Momentum in Thermomagnetic Torque Experiments  

E-print Network

June 1974) The conservation of orbital angular momentum has the following consequence for Scott-effect experiments: The torque exerted on the outer cylinder is equal in size but opposite in direction to the torque on the inner cylinder. This is true... for each of the two contributions to the torque, namely, the bulk and slip contribution. I. INTRODUCTION Recently Wood et al. ' reported an experimental study of the conservation of angular momentum in thermomagnetic torque experiments (Scott ef...

Vestner, H.; Adair, Thomas W.

1975-01-01

232

Consumers' willingness to pay for organic food : Factors that affect it and variation per organic product type  

Microsoft Academic Search

Purpose – Seeks to provide answers to two questions: is willingness to pay (WTP) for organic products influenced by the same set of factors that affect purchasing of conventional foods? Does WTP for organic products vary according to different food categories? Design\\/methodology\\/approach – Purchasers were approached during their food shopping in retail chains in Athens in July 2003. Sample inclusion

Athanasios Krystallis; George Chryssohoidis

2005-01-01

233

Performances improvements and torque ripple minimization for VSI fed induction machine with direct control torque.  

PubMed

This paper describes a torque ripple reduction technique with constant switching frequency for direct torque control (DTC) of an induction motor (IM). This method enables a minimum torque ripple control. In order to obtain a constant switching frequency and hence a torque ripple reduction, we propose a control technique for IM. It consists of controlling directly the electromagnetic torque by using a modulated hysteresis controller. The design methodology is based on space vector modulation (SVM) of electrical machines with digital vector control. MATLAB simulations supported with experimental study are used. The simulation and experimental results of this proposed algorithm show an adequate dynamic to IM; however, the research can be extended to include synchronous motors as well. The implementation of the proposed algorithm is described. It doesn't require any PI controller in the torque control loop. The hardware inverter is controlled digitally using a Texas Instruments TMS320F240 digital signal processor (DSP) with composed C codes for generating the required references. The results obtained from simulation and experiments confirmed the feasibility of the proposed strategy compared to the conventional one. PMID:21193193

Abdelli, R; Rekioua, D; Rekioua, T

2011-04-01

234

Staphylococcus aureus CcpA affects virulence determinant production and antibiotic resistance.  

PubMed

Carbon catabolite protein A (CcpA) is known to function as a major regulator of gene expression in different gram-positive organisms. Deletion of the ccpA homologue (saCOL1786) in Staphylococcus aureus was found to affect growth, glucose metabolization, and transcription of selected virulence determinants. In liquid culture, deletion of CcpA decreased the growth rate and yield; however, the effect was only transient during the exponential-growth phase as long as glucose was present in the medium. Depletion of glucose and production of lactate was delayed, while the level of excretion of acetate was less affected and was even higher in the mutant culture. On solid medium, in contrast, growth of the DeltaccpA mutant resulted in smaller colonies containing a lower number of CFU per colony. Deletion of CcpA had an effect on the expression of important virulence factors of S. aureus by down-regulating RNAIII, the effector molecule of the agr locus, and altering the transcription patterns of hla, encoding alpha-hemolysin, and spa, encoding protein A. CcpA inactivation markedly reduced the oxacillin resistance levels in the highly methicillin-resistant S. aureus strain COLn and the teicoplanin resistance level in a glycopeptide-intermediate-resistant S. aureus strain. The presence of CcpA in the capsular polysaccharide serotype 5 (CP5)-producing strain Newman abolished capsule formation and decreased cap operon transcription in the presence of glucose. The staphylococcal CcpA thus not only is involved in the regulation of carbon metabolism but seems to function as a modulator of virulence gene expression as well. PMID:16569828

Seidl, Kati; Stucki, Martin; Ruegg, Martin; Goerke, Christiane; Wolz, Christiane; Harris, Llinos; Berger-Bächi, Brigitte; Bischoff, Markus

2006-04-01

235

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, 2012 CFR

...Compliance With the Emission Limits for Tire Production Affected Sources 9 Table...Standards for Hazardous Air Pollutants: Rubber Tire Manufacturing Pt. 63, Subpt. XXXX...Compliance With the Emission Limits for Tire Production Affected Sources As...

2012-07-01

236

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

...Compliance With the Emission Limits for Tire Production Affected Sources 9 Table...Standards for Hazardous Air Pollutants: Rubber Tire Manufacturing Pt. 63, Subpt. XXXX...Compliance With the Emission Limits for Tire Production Affected Sources As...

2014-07-01

237

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, 2011 CFR

...Compliance With the Emission Limits for Tire Production Affected Sources 9 Table...Standards for Hazardous Air Pollutants: Rubber Tire Manufacturing Pt. 63, Subpt. XXXX...Compliance With the Emission Limits for Tire Production Affected Sources As...

2011-07-01

238

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, 2012 CFR

...Compliance With the Emission Limits for Tire Cord Production Affected Sources 11...Standards for Hazardous Air Pollutants: Rubber Tire Manufacturing Pt. 63, Subpt. XXXX...Compliance With the Emission Limits for Tire Cord Production Affected Sources...

2012-07-01

239

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

...Compliance With the Emission Limits for Tire Production Affected Sources 9 Table...Standards for Hazardous Air Pollutants: Rubber Tire Manufacturing Pt. 63, Subpt. XXXX...Compliance With the Emission Limits for Tire Production Affected Sources As...

2010-07-01

240

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, 2010 CFR

...Compliance With the Emission Limits for Tire Cord Production Affected Sources 11...Standards for Hazardous Air Pollutants: Rubber Tire Manufacturing Pt. 63, Subpt. XXXX...Compliance With the Emission Limits for Tire Cord Production Affected Sources...

2010-07-01

241

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

...Compliance With the Emission Limits for Tire Cord Production Affected Sources 11...Standards for Hazardous Air Pollutants: Rubber Tire Manufacturing Pt. 63, Subpt. XXXX...Compliance With the Emission Limits for Tire Cord Production Affected Sources...

2013-07-01

242

40 CFR Table 11 to Subpart Xxxx of... - Minimum Data for Continuous Compliance With the Emission Limits for Tire Cord Production Affected...  

...Compliance With the Emission Limits for Tire Cord Production Affected Sources 11...Standards for Hazardous Air Pollutants: Rubber Tire Manufacturing Pt. 63, Subpt. XXXX...Compliance With the Emission Limits for Tire Cord Production Affected Sources...

2014-07-01

243

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, 2011 CFR

...Compliance With the Emission Limits for Tire Cord Production Affected Sources 11...Standards for Hazardous Air Pollutants: Rubber Tire Manufacturing Pt. 63, Subpt. XXXX...Compliance With the Emission Limits for Tire Cord Production Affected Sources...

2011-07-01

244

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, 2013 CFR

...Compliance With the Emission Limits for Tire Production Affected Sources 9 Table...Standards for Hazardous Air Pollutants: Rubber Tire Manufacturing Pt. 63, Subpt. XXXX...Compliance With the Emission Limits for Tire Production Affected Sources As...

2013-07-01

245

Factors affecting the productivity of manufacturing sector in Sri Lanka: a spatial analysis  

Microsoft Academic Search

Two indexes of productivity — labour productivity and capital productivity — have been employed to measure and map productivity patterns of manufacturing industries in Sri Lanka. There exist extensive regional differences in the levels of productivity. Regression results show that the spatial variation of labour productivity is positively related to capital intensity and the level of urbanization and is negatively

Sriyani Dias

1991-01-01

246

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. PMID:22536344

Lech, Gregory P.; Reigh, Robert C.

2012-01-01

247

Denitrifying bacterial communities affect current production and nitrous oxide accumulation in a microbial fuel cell.  

PubMed

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. PMID:23717427

Vilar-Sanz, Ariadna; Puig, Sebastià; García-Lledó, Arantzazu; Trias, Rosalia; Balaguer, M Dolors; Colprim, Jesús; Bañeras, Lluís

2013-01-01

248

EMG-Torque Estimation of Constant-Posture, Quasi-Constant-Torque Contractions at Varied Joint Angles  

E-print Network

relates the simultaneous biceps/triceps surface electromyogram (EMG) of 12 subjects to elbow torque A significant literature has developed around the problem of relating the surface EMG to muscle tensionsEMG-Torque Estimation of Constant-Posture, Quasi- Constant-Torque Contractions at Varied Joint

Clancy, Ted

249

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

250

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

251

Biotic and abiotic factors affect green ash volatile production and emerald ash borer adult feeding preference.  

PubMed

The emerald ash borer, Agrilus planipennis Fairmaire (Coleoptera: Buprestidae), is an exotic woodborer first detected in 2002 in Michigan and Ontario and is threatening the ash resource in North America. We examined the effects of light exposure and girdling on green ash (Fraxinus pennsylvanica Marsh) volatile production, and effects of light exposure, girdling, and leaf age on emerald ash borer adult feeding preferences and phototaxis. Green ash seedlings grown under higher light exposure had lower amounts of three individual volatile compounds, (Z)-3-hexenol, (E)-beta-ocimene, and (Z,E)-alpha-farnesene, as well as the total amount of six detected volatile compounds. Girdling did not affect the levels of these volatiles. Emerald ash borer females preferred mature leaves, leaves from girdled trees, and leaves grown in the sun over young leaves, leaves from nongirdled trees, and leaves grown in the shade, respectively. These emerald ash borer preferences were most likely because of physical, nutritional, or biochemical changes in leaves in response to the different treatments. Emerald ash borer females and males showed positive phototaxis in laboratory arenas, a response consistent with emerald ash borer preference for host trees growing in sunlight. PMID:20021772

Chen, Yigen; Poland, Therese M

2009-12-01

252

Impact of finger posture on mapping from muscle activation to joint torque  

Microsoft Academic Search

Background. The mapping from muscle activation to joint torque production can be difficult to determine for the multi-articular muscles of the fingers. This relationship was examined in vivo as a function of posture in the index finger.Methods. Five healthy adults participated in an experiment in which the seven muscles of the index finger were sequentially electrically stimulated using intramuscular electrodes.

Derek G. Kamper; Heidi C. Fischer; Erik G. Cruz

2006-01-01

253

Split torque type gearbox fault detection using acoustic emission and vibration sensors  

Microsoft Academic Search

In comparison with a traditional planetary gearbox, the split torque gearbox (STG) potentially offers lower weight, increased reliability, and improved efficiency. These benefits have driven the helicopter OEMs to develop products using the STG. However, this may pose a challenge for the current gear analysis methods used in Health and Usage Monitoring Systems (HUMS). Gear analysis uses time synchronous averages

David He; Ruoyu Li; Eric Bechhoefer

2010-01-01

254

Simulation study of the reduction of cogging torque in permanent magnet motors  

Microsoft Academic Search

The reduction of cogging torque in permanent magnet motors has been studied by varying the geometry shape of the saliencies of the armature core on stator of a 12-pole 9-tooth spindle motor. Mechanism of this reduction is explained by the minimum net integral of the product of normal and tangential magnetic flux with respect to the mechanical angle between the

Y. D. Yao; D. R. Huang; J. C. Wang; S. H. Liou; S. J. Wang; T. F. Ying; D. Y. Chiang

1997-01-01

255

A Self-Learning Solution for Torque Ripple Reduction for Non-Sinusoidal Permanent Magnet  

E-print Network

1 A Self-Learning Solution for Torque Ripple Reduction for Non-Sinusoidal Permanent Magnet Motor in a permanent-magnet non-sinusoidal synchronous motor. Solutions for calculating optimal currents are deduced PERMANENT MAGNET SYNCHRONOUS MOTORS (PMSMs) are widely used in many industrial production systems due

256

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. PMID:8298044

Berg, H C; Turner, L

1993-01-01

257

Displaceable Spur Gear Torque Controlled Driver and Method  

NASA Technical Reports Server (NTRS)

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

Cook, Joseph S., Jr. (Inventor)

1996-01-01

258

Displaceable spur gear torque controlled driver and method  

NASA Technical Reports Server (NTRS)

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

Cook, Joseph S., Jr. (inventor)

1994-01-01

259

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

260

Torque-while-turnaround scan mirror assembly  

NASA Technical Reports Server (NTRS)

Mechanical aspects in the development of an oscillating scan mirror mechanism were reviewed, that featured a remarkably low level of structural vibration for the impact energies involved in mirror oscillation. Another feature was that energy lost during impact was returned to the mirror by applying torque only during the instant of impact. Because the duration of impact was only about 0.010 second, it was critical that energy losses be minimal because there was not much time to restore them.

Starkus, C. J.

1977-01-01

261

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

262

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

263

Dynamics of a split torque helicopter transmission  

NASA Astrophysics Data System (ADS)

A high reduction ratio split torque gear train has been proposed as an alternative to a planetary configuration for the final stage of a helicopter transmission. A split torque design allows a high ratio of power-to-weight for the transmission. The design studied in this work includes a pivoting beam that acts to balance thrust loads produced by the helical gear meshes in each of two parallel power paths. When the thrust loads are balanced, the torque is split evenly. A mathematical model was developed to study the dynamics of the system. The effects of time varying gear mesh stiffness, static transmission errors, and flexible bearing supports are included in the model. The model was demonstrated with a test case. Results show that although the gearbox has a symmetric configuration, the simulated dynamic behavior of the first and second compound gears are not the same. Also, results show that shaft location and mesh stiffness tuning are significant design parameters that influence the motions of the system.

Rashidi, Majid; Krantz, Timothy

264

Effect of BMI on knee joint torques in ergometer rowing.  

PubMed

Although an authoritative panel recommended the use of ergometer rowing as a non-weight-bearing form of exercise for obese adults, the biomechanical characterization of ergometer rowing is strikingly absent. We examined the interaction between body mass index (BMI) relative to the lower extremity biomechanics during rowing in 10 normal weight (BMI 18-25), 10 overweight (BMI 25-30 kg·m?²), and 10 obese (BMI > 30 kg·m?²) participants. The results showed that BMI affects joint kinematics and primarily knee joint kinetics. The data revealed that high BMI leads to unfavorable knee joint torques, implying increased loads of the medial compartment in the knee joint that could be avoided by allowing more variable foot positioning on future designs of rowing ergometers. PMID:23549387

Roemer, Karen; Hortobagyi, Tibor; Richter, Chris; Munoz-Maldonado, Yolanda; Hamilton, Stephanie

2013-12-01

265

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

266

Nature and assessments of torque ripples 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 assessments 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. [Oak Ridge National Lab., TN (United States); Pillay, P. [Univ. of New Orleans, LA (United States)

1995-12-31

267

Some Factors Affecting Milk Production and Post Partum Body Weight of Fat-Tailed Norduz Ewes in Turkey  

Microsoft Academic Search

Bingöl, M., Aygün, T., Gökdal, Ö. and Yilmaz, A. 2005. Some factors affecting milk production and post partum body weight of fat-tailed Norduz ewes in Turkey. J. Appl. Anim. Res., 27: 125–127.This study was conducted to determine some traits of milk production and post partum body weights of Norduz ewes in Van-Norduz provinces. Overall means for lactation period, lactation milk

Mehmet Bingöl; Turgut Aygün; Özdal Gökdal; Ayhan Yilmaz

2005-01-01

268

A preliminary study of patellar tendon torques during jumping.  

PubMed

The etiology of patellar tendinopathy (jumper's knee) has been attributed to a significant increase in patellar tendon torques associated with jumping. While some investigators have suggested that patellar tendon torques are greater during takeoff, little is known about the relative magnitudes of patellar tendon torques during takeoff and landing. We hypothesized that peak patellar tendon torques are greater in jump takeoff than in landing, and that there is a linear correlation between jump height and peak patellar tendon torque. Seven asymptomatic, recreational male athletes each performed a series of 21 jumps ranging from low to maximal height. A calibrated fiber-optic sensor, implanted transversely within the patellar tendon was used to measure the knee torque during takeoff and landing. There was no significant difference in the peak patellar tendon torque experienced during takeoff and landing within individuals. There was a moderate correlation (r = .64) between maximum takeoff patellar tendon torques and jump height. There was a weak correlation (r = .52) between maximum landing patellar tendon torques and jump height. There was a moderate correlation (r = .67) between maximum 60 degrees/s isokinetic extension torque and maximum jump height. The lack of a strong correlation between jump height and patellar tendon forces during take-off or landing suggests that these forces may be technique dependent. Therefore, modifying takeoff and/or landing techniques could reduce patellar tendon force and potentially lessen the incidence of patellar tendinopathy. PMID:20095457

Elvin, Niell; Elvin, Alex; Scheffer, Cornie; Arnoczky, Steven; Dillon, Edwin; Erasmus, P J

2009-11-01

269

Dynamical corotation torques on low-mass planets  

NASA Astrophysics Data System (ADS)

We study torques on migrating low-mass planets in locally isothermal discs. Previous work on low-mass planets generally kept the planet on a fixed orbit, after which the torque on the planet was measured. In addition to these static torques, when the planet is allowed to migrate it experiences dynamical torques, which are proportional to the migration rate and whose sign depends on the background vortensity gradient. We show that in discs a few times more massive than the minimum-mass solar nebula, these dynamical torques can have a profound impact on planet migration. Inward migration can be slowed down significantly, and if static torques lead to outward migration, dynamical torques can take over, taking the planet beyond zero-torque lines set by saturation of the corotation torque in a runaway fashion. This means that the region in non-isothermal discs, where outward migration is possible, can be larger than what would be concluded from static torques alone.

Paardekooper, S.-J.

2014-11-01

270

Bevel gear driver and method having torque limit selection  

NASA Technical Reports Server (NTRS)

This invention comprises a torque drive mechanism utilizing axially translatable, mutually engageable transmission members having mating crown gears, driven and driving members with a three-element drive train being biased together by resilient means or by a fluid actuator system, the apparatus being operable to transmit a precisely controlled degree of torque to a driven member. The apparatus is applicable for use in hand tools and as a replacement for impact torque drivers, torque wrenches, motorized screw drivers, or the like, wherein the applied torque must be precisely controlled or limited. The bevel torque drive includes a drive gear which is axially displaceable and rotatable within cylindrical driver housing, a rotatable intermediate gear, and an output gear. Key rotationally secures displaceable gear with respect to input shaft but permits axial movement therebetween. A thrust bearing is preferably connected to the lower end of shaft for support to reduce play and friction between shaft and a transmission joint disc during rotation of the gear train. Coaxially mounted coiled spring is footed against displaceable gear for biasing the displaceable gear toward and into engagement with the intermediate gear for driving intermediate gear and output gear. Torque control is achieved by the use of straight or spiral beveled gears which are of configurations adapted to withdraw from mutual engagement upon the torque exceeding a predetermined limit. The novel, advantageous features of the invention include the configuration of the mating, crown gear sets and the axially translatable, slidable drive gear. The mechanism is capable of transmitting a high degree of torque within a narrow, compact transmission housing. The compact size and narrow, elongated configuration of the housing is particularly applicable for use in hand tools and in multiple torque driver mechanisms in which it is necessary to drive multiple fasteners which are located in close proximity. Prior torque drivers such as 'click-type' torque wrenches do not actually limit torque application but only provide an audible warning that the limit has been reached.

Cook, Joseph S., Jr. (inventor)

1994-01-01

271

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

272

Determining the factors affecting the consumers' willingness to pay higher prices for genetically unmodified products : Tomato case study in Turkey  

Microsoft Academic Search

Purpose – The purpose of this paper is to determine the factors affecting the consumers' willingness to pay higher prices for genetically unmodified products. Design\\/methodology\\/approach – Tomato was selected as a model crop. Data used in this study were gathered from questionnaires conducted in Tokat province of Turkey in April 2006. Questionnaires were accomplished via face-to-face interviews over 262 households.

Z. Gokalp Goktolga; Kemal Esengun

2009-01-01

273

LOOK FOR THE SIGNATURE 1 Look for the Signature: How the Infusion of Personal Signatures Affects Product Evaluations and  

E-print Network

Product Evaluations and Purchase Behavior Abstract Brand managers often infuse personal signatures posit that personal signatures are multidimensional extrinsic cues that, like brands, are imbuedLOOK FOR THE SIGNATURE 1 Look for the Signature: How the Infusion of Personal Signatures Affects

Shyu, Mei-Ling

274

Embryo production in a parthenogenetic snail (Potamopyrgus antipodarum) is negatively affected by the presence of other parthenogenetic females  

E-print Network

Embryo production in a parthenogenetic snail (Potamopyrgus antipodarum) is negatively affected- thenogenetic female snails (Potamopyrgus antipodarum) is dependent on male presence. Rath- er than male to the maintenance of sex in P. antipodarum. Instead, it demonstrates that females of P. antipodarum negatively

Neiman, Maurine

275

Factors affecting the production of terpenes in seedlings of Pinus elliottii  

E-print Network

significantly, and total monoterpene production also increased but not significantly. Seedlings responded to wounding very rapidly, within one hour. Fungal infection also induced resin acid increases, but not significantly. The compositions of terpenes were... 16 18 TABLE OF CONTENTS jCONTINUED} Page Growth of seedlings Wounding effect and seedling age Total resin acid production Total monoterpene production Resin acid composition Monoterpene composition Terpene production in sterile conditions...

Ishihara, Hiroichi

2012-06-07

276

Properties of rice soils affecting methane production potentials: 1. Temporal patterns and diagnostic procedures  

Microsoft Academic Search

Thirty-one rice soils from different locations in the Philippines were incubated anaerobically for 100 d to determine methane (CH4) production potentials and to establish relationships between physico-chemical properties of soil and CH4 production potential. These soils showed pronounced variations in pattern and magnitude of CH4 production. Total CH4 production over 100 d incubation ranged from 163 to 837 µg CH4

Sudip Mitra; Reiner Wassmann; Mahesh C. Jain; Himanshu Pathak

2002-01-01

277

Low writing energy and sub nanosecond spin torque transfer switching of in-plane magnetic tunnel junction for spin torque transfer random access memory  

Microsoft Academic Search

This work investigated in-plane MgO-based magnetic tunnel junctions (MTJs) for the application of spin torque transfer random access memory (STT-RAM). The MTJ in this work had an resistance area product (RA) = 4.3 Omega.mum2, tunneling magnetoresistance ratio ~135%, thermal stability factor Delta(H)=68 (by field measurement), and Delta(I) = 50 (by current measurement). The optimal writing energy was found to be

H. Zhao; A. Lyle; Y. Zhang; P. K. Amiri; G. Rowlands; Z. Zeng; J. Katine; H. Jiang; K. Galatsis; K. L. Wang; I. N. Krivorotov; J.-P. Wang

2011-01-01

278

Matching initial torque with different stimulation parameters influences skeletal muscle fatigue.  

PubMed

A fundamental barrier to using electrical stimulation in the clinical setting is an inability to maintain torque production secondary to muscle fatigue. Electrical stimulation parameters are manipulated to influence muscle torque production, and they may also influence fatigability during repetitive stimulation. Our purpose was to determine the response of the quadriceps femoris to three different fatigue protocols using the same initial torque obtained by altering stimulator parameter settings. Participants underwent fatigue protocols in which either pulse frequency (lowHz), pulse duration (lowPD), or voltage (lowV) was manipulated to obtain an initial torque that equaled 25% of maximum voluntary isometric contraction. Muscle soreness was reported on a visual analog scale 48 h after each fatigue test. The lowHz protocol resulted in the least fatigue (25% +/- 14%); the lowPD (50% +/- 13%) and lowV (48% +/- 14%) protocols had similar levels of fatigue. The lowHz protocol resulted in significantly less muscle soreness than the higher frequency protocols. Stimulation protocols that use a lower frequency coupled with long pulse durations and high voltages result in lesser amounts of muscle fatigue and perceived soreness. The identification of optimal stimulation patterns to maximize muscle performance will reduce the effect of muscle fatigue and potentially improve clinical efficacy. PMID:22773532

Bickel, C Scott; Gregory, Chris M; Azuero, Andres

2012-01-01

279

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

280

Spin Torque in Asymmetric CoFeB/MgO/FeB Magnetic Tunnel Junctions  

NASA Astrophysics Data System (ADS)

Recent studies have shown that the use of asymmetric electrodes in MTJs can significantly affect spin torque (ST) behavior. We will report on the measurement via spin torque ferromagnetic resonance (ST-FMR) and switching phase diagram (SPD) studies of the in-plane and field-like (out-of-plane) torkance of low resistance, asymmetric IrMn/FeB/MgO/FeCoB) and IrMn/FeCoB/MgO/FeB MTJ nanopillars in the as-grown state (TMR˜22%) and the annealed state (TMR˜90%), and in comparison to that of symmetric counterparts; IrMn/FeB/MgO/FeB) and Ir/Mn/FeCoB/MgO/FeCoB MTJs. For the asymmetric MTJs only,the ST-FMR data show a strong field-like torkance for low voltage bias V that reverses sign when the free and pinned layers are reversed. At the higher V regime explored by the SPD the equivalent linear term in the field-like torque can dominate over the in-plane torque, resulting in either the parallel or antiparallel alignment being favored for both bias polarities, depending on the composition of the free layer.

Tseng, Hsin-Wei; Li, Yun; Read, John; Ralph, Daniel; Buhrman, Robert

2012-02-01

281

Torque anomaly in quantum field theory  

NASA Astrophysics Data System (ADS)

The expectation values of energy density and pressure of a quantum field inside a wedge-shaped region appear to violate the expected relationship between torque and total energy as a function of angle. In particular, this is true of the well-known Deutsch-Candelas stress tensor for the electromagnetic field, whose definition requires no regularization except possibly at the vertex. Unlike a similar anomaly in the pressure exerted by a reflecting boundary against a perpendicular wall, this problem cannot be dismissed as an artifact of an ad hoc regularization.

Fulling, S. A.; Mera, F. D.; Trendafilova, C. S.

2013-02-01

282

Muscle torque preservation and physical activity in individuals with stroke  

PubMed Central

Background A greater percent loss of concentric versus eccentric muscle torque (i.e., relative eccentric muscle torque preservation) has been reported in the paretic limb of individuals with stroke and has been attributed to hypertonia and/or co-contractions. Stroke provides a unique condition for examining mechanisms underlying eccentric muscle preservation because both limbs experience similar amounts of general physical activity, but the paretic side is impaired directly by the brain lesion. Purpose The purpose of this study was to determine 1) whether eccentric preservation also exists in the nonparetic limb and 2) the relationship of eccentric or concentric torque preservation with physical activity in stroke. We hypothesized that the nonparetic muscles would demonstrate eccentric muscle preservation, which would suggest that non-neural mechanisms may also contribute to its relative preservation. Methods Eighteen stroke and 18 healthy control subjects (age and sex matched) completed a physical activity questionnaire. Maximum voluntary concentric and eccentric joint torques of the ankle, knee and hip flexors and extensors were measured using an isokinetic dynamometer at 30°/s for the paretic and nonparetic muscles. Relative concentric and eccentric peak torque preservation were expressed as a percentage of control subject torque. Results Relative eccentric torque was higher (more preserved) than relative concentric torque for paretic, as well as nonparetic muscles. Physical activity correlated with paretic (r=0.640, p=0.001) and nonparetic concentric torque preservation (r=0.508, p=0.009), but not with eccentric torque preservation for either leg. Conclusions The relative preservation of eccentric torque in the nonparetic muscles suggest a role of non-neural mechanisms and could also explain the preservation observed in other chronic health conditions. Loss of concentric, but not eccentric muscle torque was related to physical inactivity in stroke. PMID:19516167

Eng, Janice J.; Lomaglio, Melanie J.; MacIntyre, Donna L.

2011-01-01

283

Preparation Torque Limit for Composites Joined with Mechanical Fasteners  

NASA Technical Reports Server (NTRS)

Current design guidelines for determining torque ranges for composites are based on tests and analysis from isotropic materials. Properties of composites are not taken into account. No design criteria based upon a systematic analytical and test analyses is available. This paper is to study the maximum torque load a composite component could carry prior to any failure. Specifically, the torque-tension tests are conducted. NDT techniques including acoustic emission, thermography and photomicroscopy are also utilized to characterize the damage modes.

Thomas, Frank P.; Yi, Zhao

2005-01-01

284

Torque-angle loops in multimachine power systems  

Microsoft Academic Search

The synchronizing and damping torques are derived from the torque-angle loop of a single machine infinite bus-bar system. This paper uses frequency response methods to generalize the analysis to an n machine system. A transfer function matrix G(s) is derived to relate the n-vector of electrical torques to the n-vector of rotor angles. The characteristic locus method is used to

A. M. A. HAMDAN

1984-01-01

285

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

286

Factors affecting egg production, body weight, and feed efficiency, of selected strains of cage layers  

E-print Network

AND DISCUSSION ~ ~ ~ A. Feed Efficiency B. Egg Production C. Body Weights D. Egg Weights. E. Pause in Production. F. Effect of Position Page 1 7 9 . 11 . 12 . 14 . 15 . 16 G. Cage Performance Versus Floor Performanoe. . . 18 H ~ Age to 50 Percent... ~ Statistical comparison of White Inbred Hybrid No. 1, and Inbred for initial body weight, change average body ~eight, and age to production Leghorns, Hybrid No. 2, in body weighted 50 percent 29 VII ' Statistical comparison of White Leghorns, Inbred...

Miller, Marshall Middleton

2012-06-07

287

Synthesis and Review of US Research on the Physical and Biological Factors Affecting Ocean Production of Salmon  

E-print Network

Abstract: This paper is a synthesis and review of the results of US research in the 1990s on the physical and biological factors affecting ocean production of Pacific salmon (Oncorhynchus spp.). The review follows the outline of US research under the North Pacific Anadromous Fish Commission Science Plan, which addresses issues concerning the ocean production of salmon. The research includes studies on juvenile salmon in coastal waters, ecology of salmon in the Gulf of Alaska, retrospective analyses of long-term data series, development and application of stock identification techniques, and international cooperative high seas salmon research. Our review indicates that climate-induced variation in productivity and fishing are the two major factors affecting ocean production of salmon, but the underlying mechanisms are not well known. To understand the processes linking climate, ocean productivity, and salmon production, we need stock-specific information on salmon distribution, abundance, and migration patterns with respect to environmental conditions. We recommend continuation of this research, with a strong emphasis on (1) the development of new technologies and international baselines for salmon stock identification, (2) shipboard research and monitoring programs to provide a platform for process studies, as well as data on interannual variation in ocean growth, distribution, and run timing of key stocks, and (3) the development

Katherine W. Myersl; Robert V. Walkeri; H. Richard Carlson T; John H. Helle; Fish Comm; Bull No

288

Dynamics of railway wagons subjected to braking torques on defective tracks  

Microsoft Academic Search

It is well known that track defects cause profound effects to the dynamics of railway wagons; normally such problems are examined for cases of wagons running at a constant speed. Brake\\/traction torques affect the speed profile due to the wheel–rail contact characteristics but most of the wagon–track interaction models do not explicitly consider them in simulation. The authors have recently

Zuoyan Zhang; Manicka Dhanasekar

2012-01-01

289

Dynamics of railway wagons subjected to braking torques on defective tracks  

Microsoft Academic Search

It is well known that track defects cause profound effects to the dynamics of railway wagons; normally such problems are examined for cases of wagons running at a constant speed. Brake\\/traction torques affect the speed profile due to the wheel–rail contact characteristics but most of the wagon–track interaction models do not explicitly consider them in simulation. The authors have recently

Zuoyan Zhang; Manicka Dhanasekar

2011-01-01

290

Mould growth and mycotoxin production as affected by Equisetum arvense and Stevia rebaudiana extracts  

Microsoft Academic Search

Cereals are very important for human and animal diet. However, agricultural products can be contaminated by moulds and their mycotoxins. On the other hand, natural plant products with antimicrobial properties could be a possibility to control mycotoxigenic fungi in foods and feeds. In this study, Equisetum arvense and Stevia rebaudiana extracts were tested for their efficacy against a range of

Daiana Garcia; Esther Garcia-Cela; Antonio J. Ramos; Vicente Sanchis; Sonia Marín

2011-01-01

291

In situ extraction strategy affects benzophenanthridine alkaloid production fluxes in suspension cultures of Eschscholtzia californica.  

PubMed

The effect of contact between cells and extractive phase on secondary metabolite production was investigated in two-phase suspension cultures of Eschscholtzia californica. A system was designed to extract benzophenanthridine alkaloids from the cell culture, without contact between XAD-7 resins and the cells: only medium was recirculated through a column packed with the extractive phase. This strategy was compared to the classic method of addition of resins directly into the cell suspension. Removal of the product directly from the medium enabled important increases in production of alkaloids, namely a 20-fold increase in sanguinarine production and a 10-fold increase in chelerythrine, with high recovery in the resin. The recirculation strategy greatly simplified the production process since the resins are easily recovered from the cell culture and enable harvest of product without termination of culture. However, due to limited flow rate, the recirculation strategy was slightly less effective than direct addition of resins into the cell suspension. In addition to enabling increased production, removal of secondary metabolites from the medium changed metabolic flux distribution, testifying to a complex control mechanism of production. PMID:15744839

Klvana, M; Legros, R; Jolicoeur, M

2005-02-01

292

Factors Affecting the Water Holding Capacity of Red Meat Products: A Review of Recent Research Advances  

Microsoft Academic Search

The water holding capacity of meat products is a very important quality attribute which has an influence on product yield, which in turn has economic implications, but is also important in terms of eating quality. A number of pre-and post-mortem factors influence the water holding capacity (WHC) of meat. During the growth and development of meat animals, genotype and animal

Qiaofen Cheng; Da-Wen Sun

2008-01-01

293

Torque-ripple minimization in switched reluctance motors using adaptive fuzzy control  

Microsoft Academic Search

An adaptive fuzzy control scheme for the torque-ripple minimization of switched reluctance machines is presented. The fuzzy parameters are initially chosen randomly and then adjusted to optimize the control. The controller produces smooth torque up to the motor base speed. The torque is generated over the maximum positive torque-producing region of a phase. This increases the torque density and avoids

S. Mir; M. E. Elbuluk; I. Husain

1999-01-01

294

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

295

Factors Affecting Carbohydrate Production and Loss in Salt Marsh Sediments of Galveston Bay  

E-print Network

Benthic microalgae (BMA) living within the surface sediment of salt marshes are highly productive organisms that provide a significant proportion of organic carbon inputs into estuarine systems. BMA secrete extracellular carbohydrates in the form...

Wilson, Carolyn E.

2010-10-12

296

40 CFR Table 3 to Subpart Nnnnn of... - Performance Test Requirements for HCl Production Affected Sources  

Code of Federal Regulations, 2010 CFR

...the following requirements for performance tests for HCl production for each...for which you are conducting a performance test, you must . . . Using...with which you will demonstrate continuous compliance with the...

2010-07-01

297

Canola Oil Production and Nutrient Uptake as Affected by Phosphate Solubilizing and Sulfur Oxidizing Bacteria  

Microsoft Academic Search

Canola (Brassica napus L.) is a very important agricultural and industrial crop. Hence, the effects of chemical and biological treatments on canola oil production and nutrient uptake, under calcareous conditions, were evaluated in a field experiment. Phosphorus (P) fertilizer and sulfur (S)-oxidizing bacteria (Thiobacillus sp.) increased canola oil production by a maximum of 548 and 335 kg ha, respectively. P-solubilizing bacteria

S. Salimpour; K. Khavazi; H. Nadian; H. Besharati; Mohammad Miransari

2012-01-01

298

Are Wages and Productivity in Zimbabwe Affected by Human Capital Investment and International Trade?  

Microsoft Academic Search

April 1999Education, training, and increased openness to international markets appear to improve wages and productivity, but Zimbabwe's labor market is segmented, rather than competitive. Workers with similar skills in different sectors do not earn equal wages.To analyze what determines wages and productivity in Zimbabwe, Verner analyzes an employer\\/employee dataset from Zimbabwe's manufacturing sector. Verner finds that:? Formal education, training, and

Dorte Verner

1999-01-01

299

Experimental Investigation on Cold-Roll-Forming Process Effects of Forming Factors and Process Variables on Product Shape, Forming Loads and Torques in Forming Process for Fundamental Cross-Sectional Profiles.  

National Technical Information Service (NTIS)

The effects of various forming factors and process variables on the forming of sheet metal products are discussed. The forming factors are identified and their contribution to the mechanical properties of the metal sheet are defined. The subjects discusse...

H. Suzuki, M. Kiuchi, S. Nakajima

1972-01-01

300

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

301

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

302

Sprouting, plant growth, and tuber production as affected by chemical treatment of white potato seed pieces  

Microsoft Academic Search

Summary  Whole, dormant or sprouted seed potatoes were treated with various concentrations of gibberellic acid, cut, and planted at\\u000a three locations. Emergence of plants from treated seed was more rapid than from untreated seed. However, vigorously sprouting\\u000a seed is less affected by GA than dormant seed. Concentrations of GA as high as 5 ppm had no material effect upon total yield

Herman Timm; Lawrence Rappaport; J. C. Bishop; B. J. Hoyle

1962-01-01

303

Tuberous sclerosis causing mutants of the TSC2 gene product affect proliferation and p27 expression  

Microsoft Academic Search

The autosomal dominant disease tuberous sclerosis (TSC) is caused by mutations in either TSC1 on chromosome 9q34, encoding hamartin, or TSC2 on chromosome 16p13.3, encoding tuberin. TSC is characterized by hamartomas that occur in many organs of affected patients and these have been considered to likely result from defects in proliferation control. Although the true biochemical functions of the two

Thomas Soucek; Margit Rosner; Angelina Miloloza; Marion Kubista; Jeremy P Cheadle; Julian R Sampson; Markus Hengstschläger

2001-01-01

304

Phylogenetic distance and species richness interactively affect the productivity of bacterial communities.  

PubMed

Our understanding of how biodiversity influences ecosystem functioning is entering a new stage of its development through the incorporation of information about the evolutionary relatedness of species. Bacteria are prime providers of essential ecosystem services, representing an excellent model system to perform biodiversity-ecosystem function research. By using bacteria isolated from petroleum-contaminated sites, we show that communities composed of poorly related species were more productive than those containing highly related species. The nature of the forces controlling this positive effect of phylogenetic diversity on community productivity depended on the number of species in culture. In communities of two species the positive effect of phylogenetic diversity on productivity was driven by changes in the selection effect. Communities of two distantly related species were dominated by the most productive species in monoculture, whereas communities of two closely related species were dominated by the less productive species in monoculture. In communities of four species the positive effect of phylogenetic diversity on productivity was driven by changes in the complementarity effect. In communities composed of four distantly related species the influence of positive interactions such as facilitation, cross-feeding, and niche partitioning seemed to outweigh the influence of negative interactions such as interference. As a consequence the proportion of species favored by the presence of other species increased as they became less related. Multiple facets of biodiversity may influence ecosystem functioning. Here, we present evidence of an interaction between phylogenetic and taxonomic diversity on community productivity, underlining the importance of considering multiple aspects of biodiversity when studying its impact on ecosystem functioning. PMID:24400504

Venail, Patrick A; Vives, Martha J

2013-11-01

305

Intra-seasonal precipitation amount and pattern differentially affect primary production of two dominant species of Inner Mongolia grassland  

NASA Astrophysics Data System (ADS)

Understanding impacts of changed precipitation regimes on plant primary production at species level is critical for predicting ecosystem responses to climate change. We examined the responses of two dominant species of Inner Mongolia grassland to altered seasonal precipitation regimes by a manipulated rainout shelter experiment. With the increase of precipitation amount, the perennial rhizomatous grass Leymus chinensis increased below-ground biomass while the perennial bunchgrass Stipa grandis increased above-ground biomass. With the increase of the interval between rainfall events, biomass production of L. chinensis reduced significantly while S. grandis was not affected. Soil moisture and inorganic nitrogen are two dominant environmental factors affecting plant responses in biomass production. Plant functional traits, such as leaf area, leaf number, leaf photosynthetic rate and water use efficiency, also played important roles in affecting species' responses to altered precipitation regimes. Our results clearly showed that two species differed significantly in their responses to altered intra-seasonal precipitation regimes, suggesting that the structure and functioning of grassland ecosystem may be significantly altered by specific species responses to future climate change.

Liu, Yanshu; Pan, Qingmin; Zheng, Shuxia; Bai, Yongfei; Han, Xingguo

2012-10-01

306

An experimental study on fermentative H? production from food waste as affected by pH.  

PubMed

Batch dark fermentation experiments were performed on food waste and mixtures of food waste and wastewater activated sludge to evaluate the influence of pH on biological H2 production and compare the process performance with and without inoculum addition. The effect of a preliminary thermal shock treatment of the inoculum was also investigated as a means to harvest the hydrogenogenic biomass. The best performance in terms of both H2 generation potential and process kinetics was observed at pH=6.5 under all experimental conditions (no inoculum, and untreated or thermally treated inoculum added). H2 production from food waste was found to be feasible even without inoculum addition, although thermal pre-treatment of the inoculum notably increased the maximum production and reduced the lag phase duration. The analysis of the fermentation products indicated that the biological hydrogen production could be mainly ascribed to a mixed acetate/butyrate-type fermentation. However, the presence of additional metabolites in the digestate, including propionate and ethanol, also indicated that other metabolic pathways were active during the process, reducing substrate conversion into hydrogen. The plateau in H2 generation was found to mirror the condition at which soluble carbohydrates were depleted. Beyond this condition, homoacetogenesis probably started to play a role in the degradation process. PMID:24833177

Cappai, G; De Gioannis, G; Friargiu, M; Massi, E; Muntoni, A; Polettini, A; Pomi, R; Spiga, D

2014-08-01

307

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

308

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

309

14 CFR 23.397 - Limit control forces and -torques.  

Code of Federal Regulations, 2010 CFR

...2010-01-01 false Limit control forces and -torques. 23.397 Section 23...System Loads § 23.397 Limit control forces and -torques. (a) In the control...flight from the application of any pilot force within the ranges specified in...

2010-01-01

310

40 CFR 90.306 - Dynamometer torque cell calibration.  

Code of Federal Regulations, 2010 CFR

...2010-07-01 false Dynamometer torque cell calibration. 90.306 Section 90...Provisions § 90.306 Dynamometer torque cell calibration. (a)(1) Any lever...system. (b) Option. A master load-cell or transfer standard may be used to...

2010-07-01

311

40 CFR 91.306 - Dynamometer torque cell calibration.  

Code of Federal Regulations, 2010 CFR

...2010-07-01 false Dynamometer torque cell calibration. 91.306 Section 91...Provisions § 91.306 Dynamometer torque cell calibration. (a)(1) Any lever...system. (b) Option. A master load-cell or transfer standard may be used to...

2010-07-01

312

14 CFR 29.397 - Limit pilot forces and torques.  

Code of Federal Regulations, 2010 CFR

...2010-01-01 false Limit pilot forces and torques. 29.397 Section...Loads § 29.397 Limit pilot forces and torques. (a) Except...this section, the limit pilot forces are as follows: (1) For...within 20 degrees of the plane of motion of the control. (2)...

2010-01-01

313

14 CFR 27.397 - Limit pilot forces and torques.  

Code of Federal Regulations, 2011 CFR

...2011-01-01 false Limit pilot forces and torques. 27.397 Section...Loads § 27.397 Limit pilot forces and torques. (a) Except...this section, the limit pilot forces are as follows: (1) For...within 20 degrees of the plane of motion of the control. (2)...

2011-01-01

314

14 CFR 29.397 - Limit pilot forces and torques.  

...2014-01-01 false Limit pilot forces and torques. 29.397 Section...Loads § 29.397 Limit pilot forces and torques. (a) Except...this section, the limit pilot forces are as follows: (1) For...within 20 degrees of the plane of motion of the control. (2)...

2014-01-01

315

14 CFR 29.397 - Limit pilot forces and torques.  

Code of Federal Regulations, 2011 CFR

...2011-01-01 false Limit pilot forces and torques. 29.397 Section...Loads § 29.397 Limit pilot forces and torques. (a) Except...this section, the limit pilot forces are as follows: (1) For...within 20 degrees of the plane of motion of the control. (2)...

2011-01-01

316

14 CFR 29.397 - Limit pilot forces and torques.  

Code of Federal Regulations, 2013 CFR

...2013-01-01 false Limit pilot forces and torques. 29.397 Section...Loads § 29.397 Limit pilot forces and torques. (a) Except...this section, the limit pilot forces are as follows: (1) For...within 20 degrees of the plane of motion of the control. (2)...

2013-01-01

317

14 CFR 27.397 - Limit pilot forces and torques.  

Code of Federal Regulations, 2013 CFR

...2013-01-01 false Limit pilot forces and torques. 27.397 Section...Loads § 27.397 Limit pilot forces and torques. (a) Except...this section, the limit pilot forces are as follows: (1) For...within 20 degrees of the plane of motion of the control. (2)...

2013-01-01

318

14 CFR 27.397 - Limit pilot forces and torques.  

Code of Federal Regulations, 2010 CFR

...2010-01-01 false Limit pilot forces and torques. 27.397 Section...Loads § 27.397 Limit pilot forces and torques. (a) Except...this section, the limit pilot forces are as follows: (1) For...within 20 degrees of the plane of motion of the control. (2)...

2010-01-01

319

14 CFR 27.397 - Limit pilot forces and torques.  

Code of Federal Regulations, 2012 CFR

...2012-01-01 false Limit pilot forces and torques. 27.397 Section...Loads § 27.397 Limit pilot forces and torques. (a) Except...this section, the limit pilot forces are as follows: (1) For...within 20 degrees of the plane of motion of the control. (2)...

2012-01-01

320

14 CFR 27.397 - Limit pilot forces and torques.  

...2014-01-01 false Limit pilot forces and torques. 27.397 Section...Loads § 27.397 Limit pilot forces and torques. (a) Except...this section, the limit pilot forces are as follows: (1) For...within 20 degrees of the plane of motion of the control. (2)...

2014-01-01

321

14 CFR 29.397 - Limit pilot forces and torques.  

Code of Federal Regulations, 2012 CFR

...2012-01-01 false Limit pilot forces and torques. 29.397 Section...Loads § 29.397 Limit pilot forces and torques. (a) Except...this section, the limit pilot forces are as follows: (1) For...within 20 degrees of the plane of motion of the control. (2)...

2012-01-01

322

40 CFR 91.306 - Dynamometer torque cell calibration.  

Code of Federal Regulations, 2013 CFR

...2013-07-01 false Dynamometer torque cell calibration. 91.306 Section 91...Provisions § 91.306 Dynamometer torque cell calibration. (a)(1) Any lever...system. (b) Option. A master load-cell or transfer standard may be used to...

2013-07-01

323

40 CFR 90.306 - Dynamometer torque cell calibration.  

Code of Federal Regulations, 2012 CFR

...2012-07-01 false Dynamometer torque cell calibration. 90.306 Section 90...Provisions § 90.306 Dynamometer torque cell calibration. (a)(1) Any lever...system. (b) Option. A master load-cell or transfer standard may be used to...

2012-07-01

324

40 CFR 91.306 - Dynamometer torque cell calibration.  

Code of Federal Regulations, 2012 CFR

...2012-07-01 false Dynamometer torque cell calibration. 91.306 Section 91...Provisions § 91.306 Dynamometer torque cell calibration. (a)(1) Any lever...system. (b) Option. A master load-cell or transfer standard may be used to...

2012-07-01

325

Study of Fuzzy Control in Direct Torque Control system  

Microsoft Academic Search

Due to the multi-variable, strong coupling, nonlinear and time-varying characteristics of induction motor, it is not easy for direct torque control (DTC) system with traditional PID controller to get ideal performance. In order to improve the performance of Direct Torque Control system, a fuzzy PID regulator of motor speed is proposed to adjust the nonlinear control variable. According to the

Mei Baishan; Liu Haihua; Zhang Jinping

2009-01-01

326

Subsynchronous torque calculation in a shaded pole hysteresis motor  

Microsoft Academic Search

This paper deals with the synchronous dips in the torque-speed characteristic of a shaded pole hysteresis motor. The case under consideration is that of the synchronous dip related to the third harmonic of the air-gap field. First we show that the torque Varies between a maximum and a minimum value when the motor runs at one third of synchronous speed

J. Perard; M. Poloujadoff

1976-01-01

327

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

328

Torque measurement methods for very high speed synchronous motors  

Microsoft Academic Search

The article presents two different torque measurement methods for very high speed synchronous motors: one uses an eddy current brake, and the other is an inertial method. The article also presents a ball bearings friction torque measurement method designed for very high speeds.

Pierre-Daniel Pfister; Yves Perriard

2008-01-01

329

Harmonic Torque Calculation of Induction Motors Using Electromagnetic Field Analysis  

Microsoft Academic Search

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

Katsumi Yamazaki; Yoshihisa Haruishi; Takahiro Ara

2004-01-01

330

40 CFR 91.306 - Dynamometer torque cell calibration.  

...2013-07-01 true Dynamometer torque cell calibration. 91.306 Section 91...Provisions § 91.306 Dynamometer torque cell calibration. (a)(1) Any lever...system. (b) Option. A master load-cell or transfer standard may be used to...

2014-07-01

331

40 CFR 90.306 - Dynamometer torque cell calibration.  

...2013-07-01 true Dynamometer torque cell calibration. 90.306 Section 90...Provisions § 90.306 Dynamometer torque cell calibration. (a)(1) Any lever...system. (b) Option. A master load-cell or transfer standard may be used to...

2014-07-01

332

40 CFR 91.306 - Dynamometer torque cell calibration.  

Code of Federal Regulations, 2011 CFR

...2011-07-01 false Dynamometer torque cell calibration. 91.306 Section 91...Provisions § 91.306 Dynamometer torque cell calibration. (a)(1) Any lever...system. (b) Option. A master load-cell or transfer standard may be used to...

2011-07-01

333

40 CFR 90.306 - Dynamometer torque cell calibration.  

Code of Federal Regulations, 2011 CFR

...2011-07-01 false Dynamometer torque cell calibration. 90.306 Section 90...Provisions § 90.306 Dynamometer torque cell calibration. (a)(1) Any lever...system. (b) Option. A master load-cell or transfer standard may be used to...

2011-07-01

334

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

335

"Hotness" stability of chicken hot-wing products as affected by preparation methods and storage.  

PubMed

Chicken hot-drumettes containing 2% cayenne pepper were prepared using three different cooking methods and stored under two different temperatures for "hotness" evaluation. Results demonstrated that the hotness of the samples were highest when products were cooked in a microwave oven, followed by convection oven, and least hot by deep-fat frying. Regardless of the cooking method, the degree of hotness of the hot-drumette decreased drastically during refrigerated storage. Results also indicated that the loss of hotness was associated with the increase of 2-thiobarbituric acid (TBA) values in the product. The addition of antioxidants such as butylated hydroxyanisole (BHA), butylated hydroxytoluene (BHT), rosemary, and sodium nitrate during preparation or vacuum packaging retarded lipid oxidation of chicken hot-drumettes and retarded the loss of hotness of the products during refrigerated storage. PMID:9565248

Chang, M H; Chen, T C

1998-04-01

336

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

337

Maximum Torque and Momentum Envelopes for Reaction Wheel Arrays  

NASA Technical Reports Server (NTRS)

Spacecraft reaction wheel maneuvers are limited by the maximum torque and/or angular momentum that the wheels can provide. For an n-wheel configuration, the torque or momentum envelope can be obtained by projecting the n-dimensional hypercube, representing the domain boundary of individual wheel torques or momenta, into three dimensional space via the 3xn matrix of wheel axes. In this paper, the properties of the projected hypercube are discussed, and algorithms are proposed for determining this maximal torque or momentum envelope for general wheel configurations. Practical strategies for distributing a prescribed torque or momentum among the n wheels are presented, with special emphasis on configurations of four, five, and six wheels.

Markley, F. Landis; Reynolds, Reid G.; Liu, Frank X.; Lebsock, Kenneth L.

2009-01-01

338

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

339

Torque Characteristics of Saturated Permanent-Magnet Synchronous Motors  

NASA Astrophysics Data System (ADS)

The evaluation of torque characteristics in a saturated magnetic field for permanent-magnet (PM) synchronous motors is presented. The torque saturation characteristics of non-salient and salient pole machines are investigated by finite element analysis and measurement. Thus, it is found that the torque saturation originates in the magnetic saturation in both the stator teeth, which are located on the leading position toward the direct axis, and in the stator back yoke, which is located on the lagging position toward the direct axis. This mechanism can also explain the reason for the significant torque saturation in the salient-pole machine; the higher inductance of the quadrature axis of the salient-pole machine causes a significant magnetic saturation in the stator back yoke. Therefore, less saliency or a wider back yoke can improve the torque saturation.

Takahashi, Akeshi; Kikuchi, Satoshi; Wakui, Shinichi; Mikami, Hiroyuki; Ide, Kazumasa; Shima, Kazuo

340

Torque compensation technology for the geostationary meteorological satellite  

NASA Astrophysics Data System (ADS)

To acquire high quality image, the new generation Geostationary Meteorological Satellite in China (GMSC) adopts three-axis stabilized attitude control mode, besides an advanced control system is required to be designed to get higher pointing precision and degree of stability of the satellite. However, the ability of the control system is limited. Torque compensation technology is studied in this paper aiming at rejecting the disturbance factors, which cannot be absorbed by the control system. In the research of torque compensation technology, the main factors that influence the degree of stability of satellite are analyzed; the objects compensated are confirmed through analysis of simulation; the system technical concept of torque compensation is designed; the mathematical models of the compensated objects and compensation devices are founded; the torque compensation arithmetic is designed; the valid arithmetic of torque compensation is proved through simulation. The research provides theoretical principles to develop the new generation GMSC.

Wang, Zhigang; Wang, Lusha; Chen, Shilu; Li, Qing

2009-12-01

341

Microbial Natural Products That Affect Plants, Phytopathogens, and Certain other Microorganisms  

Microsoft Academic Search

Biologically active natural products of microbial origin are diverse in chemical structure and exhibit different responses in divergent assay systems. They may have practical use as plant growth regulators, antimicrobials, and phytotoxins. In addition, they may be viewed as bioactive templates that may be altered to produce compounds with changed specific activities and target specificities.

Horace G. Cutler

1995-01-01

342

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

343

Elevated Seedbed Technique for Improved Rice Production in Flood-and Salt-Affected Areas  

Microsoft Academic Search

One of the interventions formulated to overcome saline water intrusion in Brgy. Sua, Masantol, Pampanga, Philippines was the staggered rice transplanting dates. However, field conditions in the area necessitated the use of an elevated seedbed technique to implement the trial to improve rice production. To fully understand the role of the technique, a study was conducted with the following objectives:

M. V. Lopez; E. R. Genio

2004-01-01

344

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

345

Upper Middle Mainstem Columbia River Subbasin Water Quality Parameters Affected by Hydropower Production  

E-print Network

that can occur. #12;Dissolved Oxygen Dissolved oxygen (DO) levels in the subbasin do not typically decline by Hydropower Production Total Dissolved Gas Total dissolved gas (TDG) supersaturation often occurs during (GBT), a class of harmful and potentially fatal symptoms. Total dissolved gas supersaturation

346

Personal Factors Affecting the Influence of a Marketer in the New Product Development Process  

Microsoft Academic Search

This study investigates the influence of marketers in managing a New Product Development (NPD) Project at an organisation competing in the Australian fast moving consumer goods (FMCG) industry. While the role and influence of marketers is under researched, it is widely accepted that marketers do play an important role in managing NPD Projects in organisations producing consumer goods. This case

Kerry Grigg

347

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

348

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

349

Nanofiber alignment and direction of mechanical strain affect the ECM production of human ACL fibroblast  

Microsoft Academic Search

The effects of fiber alignment and direction of mechanical stimuli on the ECM generation of human ligament fibroblast (HLF) were assessed. The nanofiber matrix was fabricated using electrospinning technique. To align the nanofibers, a rotating target was used. The HLFs on the aligned nanofibers were spindle-shaped and oriented in the direction of the nanofibers. The degree of ECM production was

Chang Hun Lee; Ho Joon Shin; In Hee Cho; Young-Mi Kang; In Ae Kim; Ki-Dong Park; Jung-Woog Shin

2005-01-01

350

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...

351

Forces and Torques on Rotating Spirochete Flagella  

NASA Astrophysics Data System (ADS)

Spirochetes are a unique group of motile bacteria that are distinguished by their helical or flat-wave shapes and the location of their flagella, which reside within the tiny space between the bacterial cell wall and the outer membrane (the periplasm). In Borrelia burgdorferi, rotation of the flagella produces cellular undulations that drive swimming. How these shape changes arise due to the forces and torques that act between the flagella and the cell body is unknown. It is possible that resistive forces come from friction or from fluid drag, depending on whether or not the flagella are in contact with the cell wall. Here, we consider both of these cases. By analyzing the motion of an elastic flagellum rotating in the periplasmic space, we show that the flagella are most likely separated from the bacterial cell wall by a lubricating layer of fluid. This analysis then provides drag coefficients for rotation and sliding of a flagellum within the periplasm.

Yang, Jing; Huber, Greg; Wolgemuth, Charles W.

2011-12-01

352

Nanomechanical torque magnetometry of permalloy cantilevers  

NASA Astrophysics Data System (ADS)

There is mounting interest in bridging the fields of nanomechanics and nanomagnetism. Metallic nanocantilevers, which are magnetic throughout their volume, were fabricated using permalloy in order to detect domain switching along the cantilever length through mechanical deflection driven by magnetic torque. A finite element model describing the interaction of the magnetization of the cantilever with an external driving field is discussed, and illustrated for the simple example of magnetization reversal via propagation of a straight domain wall. The interferometrically obtained cantilever deflection through the magnetic actuation of the fundamental mode exhibits magnetic hysteresis. The experimental results are also compared to the finite element mechanical transformation of the output from a Landau-Lifshitz-Gilbert based micromagnetic simulation of the hysteresis.

Losby, Joseph; Burgess, Jacob A. J.; Holt, Chris M. B.; Westwood, Jocelyn N.; Mitlin, David; Hiebert, Wayne K.; Freeman, Mark R.

2010-12-01

353

Forces and Torques on Rotating Spirochete Flagella  

PubMed Central

Spirochetes are a unique group of motile bacteria that are distinguished by their helical or flat-wave shapes and the location of their flagella, which reside within the tiny space between the bacterial cell wall and the outer membrane (the periplasm). In Borrelia burgdorferi, rotation of the flagella produces cellular undulations that drive swimming. How these shape changes arise due to the forces and torques that act between the flagella and the cell body is unknown. It is possible that resistive forces come from friction or from fluid drag, depending on whether or not the flagella are in contact with the cell wall. Here, we consider both of these cases. By analyzing the motion of an elastic flagellum rotating in the periplasmic space, we show that the flagella are most likely separated from the bacterial cell wall by a lubricating layer of fluid. This analysis then provides drag coefficients for rotation and sliding of a flagellum within the periplasm. PMID:22243185

Yang, Jing; Huber, Greg; Wolgemuth, Charles W.

2012-01-01

354

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

355

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

356

Radiative Torques on Interstellar Grains. I. Superthermal Spin-up  

NASA Astrophysics Data System (ADS)

Irregular dust grains are subject to radiative torques when irradiated by interstellar starlight. It is shown how these radiative torques may be calculated using the discrete dipole approximation. Calculations are carried out for one irregular grain geometry and three different grain sizes. It is shown that radiative torques can play an important dynamical role in spin-up of interstellar dust grains, resulting in rotation rates that may exceed even those expected from H2 formation on the grain surface. Because the radiative torque on an interstellar grain is determined by the overall grain geometry rather than merely the condition of the grain surface, the resulting superthermal rotation is expected to be quite long-lived. By itself, long-lived superthermal rotation would permit grain alignment by normal paramagnetic dissipation on the "Davis-Greenstein" timescale tDG. However, radiative torques arising from anisotropy of the starlight background can act directly to alter the grain alignment on times short compared to tDG. Radiative torques must therefore play a central role in the process of interstellar grain alignment. The radiative torques depend strongly on the grain size, measured by ?eff, the radius of a sphere of equal volume. In diffuse clouds, radiative torques dominate the torques due to H2 formation for ?eff = 0.2 ?m grains, but are relatively unimportant for ?eff ? 0.05 ?m grains. We argue that this may provide a natural explanation for the observation that ? 0.1 ?m grains in diffuse clouds are aligned, while there is very little alignment of ?eff 0.05 ?m grains. We show that radiative torques are ineffective at producing superthermal rotation within quiescent dark clouds, but can be very effective in star-forming regions such as the M17 molecular cloud.

Draine, B. T.; Weingartner, Joseph C.

1996-10-01

357

SCO5745, a Bifunctional RNase J Ortholog, Affects Antibiotic Production in Streptomyces coelicolor  

PubMed Central

The bacterial RNases J are considered bifunctional RNases possessing both endo- and exonucleolytic activities. We have isolated an RNase J ortholog from Streptomyces coelicolor encoded by the gene sco5745. We overexpressed a decahistidine-tagged version of SCO5745 and purified the overexpressed protein by immobilized metal ion affinity chromatography. We demonstrated the presence of both 5?-to-3? exonucleolytic and endonucleolytic activities on the Bacillus subtilis thrS transcript. Exonucleoytic activity predominated with 5? monophosphorylated thrS, while endonucleolytic activity predominated with 5? triphosphorylated thrS. While sco5745 is the only RNase J allele in S. coelicolor, the gene is not essential. Its disruption resulted in delayed production of the antibiotic actinorhodin, overproduction of undecylprodigiosin, and diminished production of the calcium-dependent antibiotic, in comparison with the parental strain. PMID:24415725

Bralley, Patricia; Aseem, Madiha

2014-01-01

358

How do strategic decisions and operative practices affect operating room productivity?  

Microsoft Academic Search

Surgical operating rooms are cost-intensive parts of health service production. Managing operating units efficiently is essential\\u000a when hospitals and healthcare systems aim to maximize health outcomes with limited resources. Previous research about operating\\u000a room management has focused on studying the effect of management practices and decisions on efficiency by utilizing mainly\\u000a modeling approach or before-after analysis in single hospital case.

Antti Peltokorpi

2011-01-01

359

Pseudomonas aeruginosa PAO1 Pyocin Production Affects Population Dynamics within Mixed-Culture Biofilms? †  

PubMed Central

Transcriptomic and phenotypic studies showed that pyocins are produced in Pseudomonas aeruginosa PAO1 aerobic and anaerobic biofilms. Pyocin activity was found to be high in slow-growing anaerobic biofilms but transient in aerobic biofilms. Biofilm coculture of strain PAO1 and a pyocin-sensitive isolate showed that pyocin production had a significant impact on bacterial population dynamics, particularly under anaerobic conditions. PMID:19060137

Waite, Richard D.; Curtis, Michael A.

2009-01-01

360

Fatty acids and oil content in white lupin seed as affected by production practices  

Microsoft Academic Search

Characteristics of the seed oil of white lupin (Lupinus albus L.), a potential alternative winter crop in the mid-Atlantic region of the United States, are not well established. Replicated\\u000a experiments were conducted during the 1998–1999 and 1999–2000 growing seasons with a determinate and an indeterminate cultivar\\u000a to characterize oil and FA in lupin seed in relation to production practices. The

Harbans L. Bhardwaj; Anwar A. Hamama; Edzard van Santen

2004-01-01

361

An empirical analysis of factors affecting the productivity of livestock in southern Botswana  

Microsoft Academic Search

This study attempts to identify factors responsible for differences in the productivity of cattle managed by private and communal livestock farmers in the southern region of Botswana during 1999\\/2000. Sample survey data are used to estimate the parameters of a block recursive regression model. Some of the equations postulated in the model are estimated with two-stage least squares (2SLS) to

M. Mahabile; Michael C. Lyne; A. Panin

2005-01-01

362

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

363

Potato Production as Affected by Crop Parameters and Meteoro Logical Elements  

Microsoft Academic Search

\\u000a Meteorological elements directly influence crop potential productivity, regulating its transpiration, photosynthesis, and\\u000a respiration processes in such a way as to control the growth and development of the plants throughout their physiological\\u000a mechanisms at a given site. The interaction of the meteorological factors with crop responses is complex and has been the\\u000a target of attention of many researchers from all over

André B. Pereira; Nilson A. Villa Nova; Antonio R. Pereira

364

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

365

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 PMID:16349177

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

1994-01-01

366

Experimental Robot Position Sensor Fault Tolerance Using Accelerometers and Joint Torque Sensors  

NASA Technical Reports Server (NTRS)

Robot systems in critical applications, such as those in space and nuclear environments, must be able to operate during component failure to complete important tasks. One failure mode that has received little attention is the failure of joint position sensors. Current fault tolerant designs require the addition of directly redundant position sensors which can affect joint design. The proposed method uses joint torque sensors found in most existing advanced robot designs along with easily locatable, lightweight accelerometers to provide a joint position sensor fault recovery mode. This mode uses the torque sensors along with a virtual passive control law for stability and accelerometers for joint position information. Two methods for conversion from Cartesian acceleration to joint position based on robot kinematics, not integration, are presented. The fault tolerant control method was tested on several joints of a laboratory robot. The controllers performed well with noisy, biased data and a model with uncertain parameters.

Aldridge, Hal A.; Juang, Jer-Nan

1997-01-01

367

Storage of parbaked bread affects shelf life of fully baked end product: a ¹H NMR study.  

PubMed

Full baking of earlier partially baked (parbaked) bread can supply fresh bread to the consumer at any time of the day. When parbaked bread loaves were stored at -25, 4 or 23°C, the extent of crumb to crust moisture migration and amylopectin retrogradation differed with storage temperature, and the firming rate was evidently lowest during frozen storage. The extent of crumb to crust moisture migration during parbaked bread storage largely determined the mass of the fresh finished bread, and its crumb and crust moisture contents. Initial NMR proton mobility, initial resilience, the extent of amylopectin retrogradation and changes in firmness and resilience during storage of fully baked bread were affected by its crumb moisture content. The lowest firming rate was observed for finished bread resulting from parbaked bread stored at -25°C, while the highest firming rate was observed for finished bread from parbaked bread stored at 23°C. PMID:25038661

Bosmans, Geertrui M; Lagrain, Bert; Ooms, Nand; Fierens, Ellen; Delcour, Jan A

2014-12-15

368

Nutrient availability affects pigment production but not growth in lichens of??biological soil crusts  

USGS Publications Warehouse

Recent research suggests that micronutrients such as Mn may limit growth of slow-growing biological soil crusts (BSCs) in some of the drylands of the world. These soil surface communities contribute strongly to arid ecosystem function and are easily degraded, creating a need for new restoration tools. The possibility that Mn fertilization could be used as a restoration tool for BSCs has not been tested previously. We used microcosms in a controlled greenhouse setting to investigate the hypothesis that Mn may limit photosynthesis and consequently growth in Collema tenax, a dominant N-fixing lichen found in BSCs worldwide. We found no evidence to support our hypothesis; furthermore, addition of other nutrients (primarily P, K, and Zn) had a suppressive effect on gross photosynthesis (P = 0.05). We also monitored the growth and physiological status of our microcosms and found that other nutrients increased the production of scytonemin, an important sunscreen pigment, but only when not added with Mn (P = 0.01). A structural equation model indicated that this effect was independent of any photosynthesis-related variable. We propose two alternative hypotheses to account for this pattern: (1) Mn suppresses processes needed to produce scytonemin; and (2) Mn is required to suppress scytonemin production at low light, when it is an unnecessary photosynthate sink. Although Mn fertilization does not appear likely to increase photosynthesis or growth of Collema, it could have a role in survivorship during environmentally stressful periods due to modification of scytonemin production. Thus, Mn enrichment should be studied further for its potential to facilitate BSC rehabilitation. ?? 2008 Elsevier Ltd.

Bowker, M. A.; Koch, G. W.; Belnap, J.; Johnson, N. C.

2008-01-01

369

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

370

Infectivity and egg production of Nematospiroides dubius as affected by space flight and ultraviolet irradiation  

NASA Technical Reports Server (NTRS)

Nematospiroides dubius was tested to determine the infective potential of the third stage larvae and the egg-production and egg-viability rates of the resulting adults after they are exposed to space flight and solar ultraviolet irradiation. The results are indicative that space-flown larvae exposed to solar ultraviolet irradiation were rendered noninfective in C57 mice, whereas flight control larvae that received no solar ultraviolet irradiation matured at the same rate as the ground control larvae. However, depressed egg viability was evident in the flight control larvae.

Long, R. A.; Ellis, W. L.; Taylor, G. R.

1973-01-01

371

Factors affecting aerobic recovery heat production and recovery ratio of frog sartorius.  

PubMed Central

1. Sartorius muscles of Rana temporaria, equilibrated at 20 degrees C in Ringer solution buffered with phosphates, were stimulated isometrically for 0.2 up to 0.75 s at lengths varying from 1.03 to 1.48 times rest length, L0. The aerobic recovery heat was measured for 10.5 min after contraction. 2. The recovery heat production had a complex time course, showing a variable delay to maximum, declining thereafter. In most cases, the rate of heat production did not decrease monotonically; attention was focused on the slow exponential decay which only persisted from 1.5-5 min after contraction. This latter part of the time course was considered as strictly aerobic and characterized by the time constant tau s. 3. Increasing the tetanus duration from 0.2 to 0.75 s increased initial heat Qi and recovery heat Qr in proportion, so that the recovery ratio R (Qr/Qi) did not change; it was equal to 1.29 +/- 0.03 (S.E.M.; n = 44) for muscles at about L0. The kinetics of heat production were modified with longer tetani; in particular, tau s was increased from 2.2 to 5.2 min. 4. When muscles were stretched beyond L0, as long as there was no increase of the resting heat rate (stretch response or 'Feng effect'), recovery heat production had a similar evolution to that in muscles at about L0; R was constant and equal to 1.21 +/- 0.03 (n = 46). 5. When muscles were sufficiently stretched to develop a stretch response, R increased proportionally to the stretch response. The effect seemed independent of the contractile machinery, as it vanished concomitantly with the stretch response, while force and Qi remained unchanged for the length considered. The kinetics were also modified--the delay to maximum was no longer detected and tau s most likely increased. 6. Substitution of 60% of the NaCl of the Ringer solution by NaI (mol/mol) produced a significant increase of R, mainly due to the increase of Qr. 7. The results show that neither the time course nor the amount of aerobic recovery heat Qr are strictly determined by the amount of initial heat Qi. The hypothesis is discussed that Qr might include a variable fraction due to processes which are not directly implicated in the actin-myosin interactions, possibly those involving the cytosolic Ca2+ concentration and the rate of resting metabolism. Images Fig. 3 PMID:2621637

Godfraind-De Becker, A

1989-01-01

372

Egg production, shell thickness, and other physiological parameters of laying hens affected by T-2 toxin.  

PubMed

T-2 toxin has been reported to cause severe oral lesions and neural disturbances in young broiler chickens. T-2 toxin, when added at a level of 20 mug per g of feed, caused oral lesions but no abnormal neural disturbances in young broiler chickens. T-2 toxin, when added at a level of 20 mug per g of feed, caused oral lesions but no abnormal neural symptoms in laying hens. T-2 toxin had no effect on either hemoglobin, hematocrit values, erythrocyte count, plasma glucose, prothrombin times, or the sizes of the liver, spleen, pancreas, and heart. Lipid content of the liver was not altered. Feed consumption, however, was reduced, as were the total plasma protein and lipid concentrations and the total leukocyte count. Most important economically was the lowered egg production and a thinner egg shell. The timing and severity of the symptoms suggest that T-2 toxin causes primary oral lesions that reduce feed consumption with a consequent reduction in serum proteins and lipids, which culminate in decreased egg production. The leucopenia and thinner egg shell may be independent systemic effects of T-2 toxin in laying hens. PMID:1147602

Wyatt, R D; Doerr, J A; Hamilton, P B; Burmeister, H R

1975-05-01

373

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

374

Egg-Laying "Intermorphs" in the Ant Crematogaster smithi neither Affect Sexual Production nor Male Parentage  

PubMed Central

We study male parentage and between-colony variation in sex allocation and sexual production in the desert ant Crematogaster smithi, which usually has only one singly-mated queen per nest. Colonies of this species are known to temporarily store nutrients in the large fat body of intermorphs, a specialized female caste intermediate in morphology between queens and workers. Intermorphs repackage at least part of this fat into consumable but viable male-destined eggs. If these eggs sometimes develop instead of being eaten, intermorphs will be reproductive competitors of the queen but—due to relatedness asymmetries—allies of their sister worker. Using genetic markers we found a considerable proportion of non-queen sons in some, but not all, colonies. Even though intermorphs produce ?1.7× more eggs than workers, their share in the parentage of adult males is estimated to be negligible due to their small number compared to workers. Furthermore, neither colony-level sex allocation nor overall sexual production was correlated with intermorph occurrence or number. We conclude that intermorph-laid eggs typically do not survive and that the storage of nutrients and their redistribution as eggs by intermorphs is effectively altruistic. PMID:24130699

Oettler, Jan; Dijkstra, Michiel B.; Heinze, Jurgen

2013-01-01

375

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

376

Dietary fat affects heat production and other variables of equine performance, under hot and humid conditions.  

PubMed

Does dietary fat supplementation during conditioning improve athletic performance, especially in the heat? Fat adaptation has been used to increase energy density, decrease bowel bulk and faecal output and reduce health risks associated with hydrolysable carbohydrate overload. It may also reduce spontaneous activity and reactivity (excitability), increase fatty acid oxidation, reduce CO2 production and associated acidosis, enhance metabolic regulation of glycolysis, improve both aerobic and anaerobic performance and substantially reduce heat production. A thermochemical analysis of ATP generation showed the least heat release during the direct oxidation of long chain fatty acids, which have a 3% advantage over glucose and 20 to 30% over short chain fatty acids and amino acids. Indirect oxidation via storage as triglyceride increased heat loss during ATP generation by 3% for stearic acid, 65% for glucose and 174% for acetic acid. Meal feeding and nutrient storage, therefore, accentuates the advantage of dietary fat. A calorimetric model was based on initial estimates of net energy for competitive work (10.76 MJ for the Endurance Test of an Olympic level 3-day-event), other work (14.4 MJ/day) and maintenance (36 MJ), then applied estimates of efficiencies to derive associated heat productions for the utilisation of 3 diets, Diet A: hay (100), Diet B: hay and oats (50:50) and Diet C: hay, oats and vegetable oil (45:45:10), the difference between the last 2 diets representing fat adaptation. During a 90.5 min speed and stamina test, heat production was estimated as 37, 35.4 and 34.6 MJ for the 3 diets, respectively, an advantage 0.8 MJ less heat load for the fat adapted horse, which would reduce water needed for evaporation by 0.33 kg and reduce body temperature increase by about 0.07 degree C. Total estimated daily heat production was 105, 93 and 88 MJ for the 3 diets, respectively, suggesting a 5 MJ advantage for the fat adapted horse (Diet C vs. Diet B). Estimated intake energy was 348, 269 and 239 MJ for the 3 diets, respectively, and corresponding daily intakes as fed were 22.2, 16.6 and 12.9 kg, an advantage of 3.7 kg for the fat adapted horse. Water requirement was estimated to decrease by about 6 kg/day in the fat adapted horse: 4 kg less faecal water output and 2 kg less water for evaporation. This model indicated that the fat supplemented diet reduced daily heat load by 5%, feed intake by 22%, faecal output (and bowel ballast) by 31% and water requirement by 12%. The advantage of fat supplementation over hay and oats was in general about half that gained by hay and oats over hay alone. PMID:8894547

Kronfeld, D S

1996-07-01

377

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

378

Algorithm for calculating torque base in vehicle traction control system  

NASA Astrophysics Data System (ADS)

Existing research on the traction control system(TCS) mainly focuses on control methods, such as the PID control, fuzzy logic control, etc, aiming at achieving an ideal slip rate of the drive wheel over long control periods. The initial output of the TCS (referred to as the torque base in this paper), which has a great impact on the driving performance of the vehicle in early cycles, remains to be investigated. In order to improve the control performance of the TCS in the first several cycles, an algorithm is proposed to determine the torque base. First, torque bases are calculated by two different methods, one based on states judgment and the other based on the vehicle dynamics. The confidence level of the torque base calculated based on the vehicle dynamics is also obtained. The final torque base is then determined based on the two torque bases and the confidence level. Hardware-in-the-loop(HIL) simulation and vehicle tests emulating sudden start on low friction roads have been conducted to verify the proposed algorithm. The control performance of a PID-controlled TCS with and without the proposed torque base algorithm is compared, showing that the proposed algorithm improves the performance of the TCS over the first several cycles and enhances about 5% vehicle speed by contrast. The proposed research provides a more proper initial value for TCS control, and improves the performance of the first several control cycles of the TCS.

Li, Hongzhi; Li, Liang; Song, Jian; Wu, Kaihui; Qiao, Yanjuan; Liu, Xingchun; Xia, Yongguang

2012-11-01

379

Development of a multilayered wide-ranged torque magnetorheological brake  

NASA Astrophysics Data System (ADS)

This paper presents the design of a multilayered magnetorheological brake from modelling to prototyping and characterization. A magnetostatic model intended to provide a specific magnetic flux density over a fluid gap regardless of the dimensions of the fluid surface is proposed. The ferromagnetic path and the coil are dimensioned in consequence. The model needs only three inputs to completely define the brake, i.e. the number of fluid gaps, the inner radius of the smallest fluid gap and the fluid gap depth. The evaluation criteria are defined by the torque density, the controllability and the reactivity, described as a function of the dimensions and the number of fluid gaps. The model has been optimized to improve the torque density. The brake has four fluid gaps and has been built and characterized. The expected torque when the fluid reaches the desired induction is 3.4 N m and the measured torque is 3.6 N m. This represents a relative error of 5.5%. The brake has 60 mm diameter, 39 mm width with a hollow shaft of 12 mm diameter. When exploited up to complete saturation, the measured torque is 5.3 N m with 19 W power consumption. The brake has a torque density of 48.1 kN m-2 and a maximum-to-minimum torque ratio of 176, with 50 ms electromechanical time constant.

Rossa, Carlos; Jaegy, Adrien; Micaelli, Alain; Lozada, José

2014-02-01

380

Standard practice for torque calibration of testing machines and devices  

E-print Network

1.1 This practice covers procedures and requirements for the calibration of torque for static and quasi-static torque capable testing machines or devices. These may, or may not, have torque indicating systems and include those devices used for the calibration of hand torque tools. Testing machines may be calibrated by one of the three following methods or combination thereof: 1.1.1 Use of standard weights and lever arms. 1.1.2 Use of elastic torque measuring devices. 1.1.3 Use of elastic force measuring devices and lever arms. 1.1.4 Any of the methods require a specific uncertainty of measurement and a traceability derived from national standards of mass and length. 1.2 The procedures of 1.1.1, 1.1.2, and 1.1.3 apply to the calibration of the torque-indicating systems associated with the testing machine, such as a scale, dial, marked or unmarked recorder chart, digital display, etc. In all cases the buyer/owner/user must designate the torque-indicating system(s) to be calibrated and included in the repor...

American Society for Testing and Materials. Philadelphia

2009-01-01

381

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

382

Factors affecting the production of nanostructure lipid carriers of valproic acid.  

PubMed

The objective of this study was to optimize a nano-lipid carrier (NLCs) of valproic acid for nasal delivery using statistical methods. NLCs were prepared by solvent diffusion method followed by ultrasonication. After a preliminary screening study using Taguchi design, the Box-Behnken statistical model using desirability function was applied to evaluate variables affecting key specifications (minimum particle size, maximum drug loading and optimum release) of nano-lipid carriers of valproic acid. Each variable was assessed at three levels of surfactant concentration, acetone/ethanol volume ratio and organic/aqueous phase volume ratio. The best predicted model for particle size and drug release was quadratic model, while for drug loading, 2 factor interaction model fitted better. The measured results for the optimized formulation were a mean size of 154 nm, 47% payload and 75% of drug content released within 21 days. The optimum formulation was obtained using 1% of Poloxamer-188 as surfactant, organic/aqueous phase volume ratio of 1/5 and acetone/ethanol volume ratio of 3/1. Overall, the results show that entrapment of valproic acid in nano-lipid carriers was achieved. Such carriers might be a promising delivery system in the treatment of seizures via the nasal route of administration. PMID:23627046

Varshosaz, Jaleh; Eskandari, Sharareh; Kennedy, Ross; Tabbakhian, Majid; Minaiyan, Mohsen

2013-02-01

383

Potato Production as Affected by Crop Parameters and Meteoro Logical Elements  

NASA Astrophysics Data System (ADS)

Meteorological elements directly influence crop potential productivity, regulating its transpiration, photosynthesis, and respiration processes in such a way as to control the growth and development of the plants throughout their physiological mechanisms at a given site. The interaction of the meteorological factors with crop responses is complex and has been the target of attention of many researchers from all over the world. There is currently a great deal of interest in estimating crop productivity as a function of climate by means of different crop weather models in order to help growers choose planting locations and timing to produce high yields with good tuber quality under site-specific atmospheric conditions. In this manuscript an agrometeorological model based on maximum carbon dioxide assimilation rates for C3 plants, fraction of photosynthetically active radiation, air temperature, photoperiod duration, and crop parameters is assessed as to its performance under tropical conditions. Crop parameters include leaf areaand harvest indexes, dry matter content of potato tubers, and crop cycles to estimate potato potential yields. Productivity obtained with the cultivar Itararé, grown with adequate soil water supply conditions at four different sites in the State of São Paulo (Itararé, Piracicaba, TatuÍ, and São Manuel), Brazil, were used to test the model. The results showed thatthe agrometeorological model tested under the climatic conditions of the State of São Paulo in general underestimated irrigated potato yield by less than 10%.This justifies the recommendation to test the performance of the model in study in other climaticregions for different crops and genotypes under optimal irrigationconditions in further scientific investigations. We reached the conclusion that the agrometeorological model taking into account information on leaf area index, photoperiod duration, photosynthetically active radiation and air temperature is feasible to estimate potential tuber yield at a commercial scale. The performance test shows that it can then be used to forecast harvest time, and also as an effective tool to predict the suitability of potential regions to the cultivation of potato crop, cultivar Itararé, at the State of São Paulo, Brazil.

Pereira, André B.; Villa Nova, Nilson A.; Pereira, Antonio R.

384

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

385

Torque characteristics of solid lubricated precision bearings during oscillatory motion  

NASA Astrophysics Data System (ADS)

MoS2 sputter-coated as well as uncoated (bare) angular-contact ball bearings were tested with various cage materials in a low-speed regime. Various self-lubricating polymers either neat or with additives and metallic cages were tested. The emphasis of this paper is to report on significant torque increases torque bumps observed during non-ball overlap, oscillatory motion for some race/cage combinations. In some race/cage combinations torque bumps can be minimized by proper run-in. No attempt was made to run the bearings to failure, although certain race/cage combinations did in fact fail before the end of test.

Bauer, Reinhold; Fleischauer, Paul D.

1994-01-01

386

Spin Pumping and Spin-Transfer Torques in Antiferromagnets  

NASA Astrophysics Data System (ADS)

Spin pumping and spin-transfer torques are two reciprocal phenomena widely studied in ferromagnetic materials. However, pumping from antiferromagnets and its relation to current-induced torques have not been explored. By calculating how electrons scatter off a normal metal-antiferromagnetic interface, we derive pumped spin and staggered spin currents in terms of the staggered field, the magnetization, and their rates of change. For both compensated and uncompensated interfaces, spin pumping is of a similar magnitude as in ferromagnets with a direction controlled by the polarization of the driving microwave. The pumped currents are connected to current-induced torques via Onsager reciprocity relations.

Cheng, Ran; Xiao, Jiang; Niu, Qian; Brataas, Arne

2014-08-01

387

Torque converter transient characteristics prediction using computational fluid dynamics  

NASA Astrophysics Data System (ADS)

The objective of this research is to investigate the transient torque converter performance used in an automobile. A new technique in computational fluid dynamics is introduced, which includes the inertia of the turbine in a three dimensional simulation of the torque converter during a launch condition. The simulation results are compared to experimental test data with good agreement across the range of data. In addition, the simulated flow structure inside the torque converter is visualized and compared to results from a steady-state calculation.

Yamaguchi, T.; Tanaka, K.

2012-11-01

388

Time domain mapping of spin torque oscillator effective energy.  

PubMed

Stochastic dynamics of spin torque oscillators can be described in terms of magnetization drift and diffusion over a current-dependent effective energy surface given by the Fokker-Planck equation. Here we present a method that directly probes this effective energy surface via time-resolved measurements of the microwave voltage generated by a spin torque oscillator. We show that the effective energy approach provides a simple recipe for predicting spectral linewidths and line shapes near the generation threshold. Our time domain technique also accurately measures the fieldlike component of spin torque in a wide range of the voltage bias values. PMID:24010473

Rowlands, Graham E; Katine, Jordan A; Langer, Juergen; Zhu, Jian; Krivorotov, Ilya N

2013-08-23

389

Spin pumping and spin-transfer torques in antiferromagnets.  

PubMed

Spin pumping and spin-transfer torques are two reciprocal phenomena widely studied in ferromagnetic materials. However, pumping from antiferromagnets and its relation to current-induced torques have not been explored. By calculating how electrons scatter off a normal metal-antiferromagnetic interface, we derive pumped spin and staggered spin currents in terms of the staggered field, the magnetization, and their rates of change. For both compensated and uncompensated interfaces, spin pumping is of a similar magnitude as in ferromagnets with a direction controlled by the polarization of the driving microwave. The pumped currents are connected to current-induced torques via Onsager reciprocity relations. PMID:25126936

Cheng, Ran; Xiao, Jiang; Niu, Qian; Brataas, Arne

2014-08-01

390

Phenotypes and gene expression profiles of Saccharopolyspora erythraea rifampicin-resistant (rif) mutants affected in erythromycin production  

PubMed Central

Background There is evidence from previous works that bacterial secondary metabolism may be stimulated by genetic manipulation of RNA polymerase (RNAP). In this study we have used rifampicin selection as a strategy to genetically improve the erythromycin producer Saccharopolyspora erythraea. Results Spontaneous rifampicin-resistant (rif) mutants were isolated from the parental strain NRRL2338 and two rif mutations mapping within rpoB, S444F and Q426R, were characterized. With respect to the parental strain, S444F mutants exhibited higher respiratory performance and up to four-fold higher final erythromycin yields; in contrast, Q426R mutants were slow-growing, developmental-defective and severely impaired in erythromycin production. DNA microarray analysis demonstrated that these rif mutations deeply changed the transcriptional profile of S. erythraea. The expression of genes coding for key enzymes of carbon (and energy) and nitrogen central metabolism was dramatically altered in turn affecting the flux of metabolites through erythromycin feeder pathways. In particular, the valine catabolic pathway that supplies propionyl-CoA for biosynthesis of the erythromycin precursor 6-deoxyerythronolide B was strongly up-regulated in the S444F mutants, while the expression of the biosynthetic gene cluster of erythromycin (ery) was not significantly affected. In contrast, the ery cluster was down-regulated (<2-fold) in the Q426R mutants. These strains also exhibited an impressive stimulation of the nitrogen regulon, which may contribute to lower erythromycin yields as erythromycin production was strongly inhibited by ammonium. Conclusion Rifampicin selection is a simple and reliable tool to investigate novel links between primary and secondary metabolism and morphological differentiation in S. erythraea and to improve erythromycin production. At the same time genome-wide analysis of expression profiles using DNA microarrays allowed information to be gained about the mechanisms underlying the stimulatory/inhibitory effects of the rif mutations on erythromycin production. PMID:19331655

Carata, Elisabetta; Peano, Clelia; Tredici, Salvatore M; Ferrari, Francesco; Tala, Adelfia; Corti, Giorgio; Bicciato, Silvio; De Bellis, Gianluca; Alifano, Pietro

2009-01-01

391

Extracellular quinones affecting methane production and methanogenic community in paddy soil.  

PubMed

This study investigated the change of CH4 production and methanogenic community in response to the presence of humic substances (humics) analogue, anthraquinone-2,6-disulfonate (AQDS). Anaerobic experiments used a Chinese paddy soil, and three concentration levels of 0.5, 5, and 20 mM AQDS were conducted. Results suggested that the effect of AQDS on methanogenesis was time-dependent and concentration-dependent. Twenty millimolars of AQDS was toxic for methanogenic activity almost for the entire experimental period. Slight inhibition of methanogenesis by AQDS respiration in the 0.5- and 5-mM AQDS-supplemented treatments occurred within the early period, while CH4 accumulated throughout the later period was approximately five and ten times greater than that of the controls without AQDS, respectively. AQDS reduction coupling to acetate oxidization enriched Geobacter species, and the mcrA-targeted T-RFLP profiles revealed significant increase of Methanosarcina at the expense of Methanobacterium in the 0.5- and 5-mM AQDS treatments. The enriched syntrophic association between Geobacter and Methanosarcina was deduced to be an effective methanogenic pathway for converting acetate to CH4 via direct interspecies electron transfer. This study implied the ecological importance of syntrophic interaction between methanogens and microorganisms enriched by anaerobic respiration of non-methanogenic terminal electron acceptors in paddy soils. PMID:23913198

Xu, Jielong; Zhuang, Li; Yang, Guiqin; Yuan, Yong; Zhou, Shungui

2013-11-01

392

Mutations in the lrpE gene of Ralstonia solanacearum affects Hrp pili production and virulence.  

PubMed

The Ralstonia solanacearum hrpB-regulated gene lrpE (hpx5/brg24) encodes a PopC-like leucine-rich repeat (LRR) protein that carries 11 tandem LRR in the central region. Defects in the lrpE gene slightly reduced the virulence of R. solanacearum on host plants and changed the bacterial morphology leading to the formation of large aggregates in a minimal medium. The aggregation in the deltalrpE background required the presence of a functional Hrp type III secretion system. In wild-type R. solanacearum, Hrp pili disappeared from the bacterial surface at the end of the exponential growth phase, when the pili form into long bundles. However, even in the late growth phase, bundled Hrp pili were still observed on the cell surface of the deltalrpE mutant. Such bundles were entangled and anchored the mutant cells in the aggregates. In contrast to PopC, LrpE accumulated in bacterial cells and did not translocate into plant cells as an effector protein. The expression levels of hrp genes increased three- to fivefold in the deltalrpE background compared with those in the wild type. We propose that LrpE may negatively regulate the production of Hrp pili on the cell surface of R. solanacearum to disperse bacterial cells from aggregates. In turn, dispersal may contribute to the movement of the pathogen in the plant vascular system and, as a consequence, the pathogenicity of R. solanacearum. PMID:16903354

Murata, Yukio; Tamura, Naoyuki; Nakaho, Kazuhiro; Mukaihara, Takafumi

2006-08-01

393

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

394

Egyptian cotton ( Gossypium barbadense) flower and boll production as affected by climatic factors and soil moisture status  

NASA Astrophysics Data System (ADS)

The information on impact of climatic factors on cotton production is not generally available, or at least not available in the required form. Understanding this impact may help physiologists determine a possible control of the flowering mechanism in the cotton plant. Two field trials were conducted to investigate the relationships between climatic factors, soil moisture status, and flower and boll production of Gossypium barbadense. The climatic factors considered were daily maximum air temperature (°C), minimum air temperature (°C), maximum-minimum temperature (diurnal temperature range) (°C), sunshine duration (h day-1), maximum relative humidity (%), minimum relative humidity (%), and wind speed (m s-1). Minimum relative humidity and sunshine duration were the most significant climatic factors affecting flower and boll retention and production. Temperature appeared to be less important in the reproduction growth stage of cotton in Egypt than minimum relative humidity and sunshine duration. The soil moisture status showed low and insignificant correlation to flower and boll production. High minimum relative humidity, short period of sunshine duration, and low temperatures enhanced flower and boll formation.

Sawan, Zakaria M.; Hanna, Louis I.; McCuistion, Willis L.; Foote, Richard J.

2010-01-01

395

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

396

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

397

A geostatistical synthesis study of factors affecting gross primary productivity in various ecosystems of North America  

NASA Astrophysics Data System (ADS)

A coupled Bayesian model selection and geostatistical regression modeling approach is adopted for empirical analysis of gross primary productivity (GPP) at six AmeriFlux sites, including the Kennedy Space Center Scrub Oak, Vaira Ranch, Tonzi Ranch, Blodgett Forest, Morgan Monroe State Forest, and Harvard Forest sites. The analysis is performed at a continuum of temporal scales ranging from daily to monthly, for a period of seven years. A total of 10 covariates representing environmental stimuli and indices of plant physiology are considered in explaining variations in GPP. Similarly to other statistical methods, the presented approach estimates regression coefficients and uncertainties associated with the covariates in a selected regression model. Unlike traditional regression methods, however, the approach also estimates the uncertainty associated with the selection of a single "best" model of GPP. In addition, the approach provides an enhanced understanding of how the importance of specific covariates changes with the examined timescale (i.e. temporal resolution). An examination of changes in the importance of specific covariates across timescales reveals thresholds above or below which covariates become important in explaining GPP. Results indicate that most sites (especially those with a stronger seasonal cycle) exhibit at least one prominent scaling threshold between the daily and 20-day temporal scales. This demonstrates that environmental variables that explain GPP at synoptic scales are different from those that capture its seasonality. At shorter time scales, radiation, temperature, and vapor pressure deficit exert the most significant influence on GPP at most examined sites. At coarser time scales, however, the importance of these covariates in explaining GPP declines. Overall, unique best models are identified at most sites at the daily scale, whereas multiple competing models are identified at longer time scales.

Yadav, V.; Mueller, K. L.; Dragoni, D.; Michalak, A. M.

2010-09-01

398

A geostatistical synthesis study of factors affecting gross primary productivity in various ecosystems of North America  

NASA Astrophysics Data System (ADS)

A coupled Bayesian model selection and geostatistical regression modeling approach is adopted for empirical analysis of gross primary productivity (GPP) at six AmeriFlux sites, including the Kennedy Space Center Scrub Oak, Vaira Ranch, Tonzi Ranch, Blodgett Forest, Morgan Monroe State Forest, and Harvard Forest sites. The analysis is performed at a continuum of temporal scales ranging from daily to monthly, for a period of seven years. A total of 10 covariates representing environmental stimuli and indices of plant physiology are considered in explaining variations in GPP. Similar to other statistical methods, the proposed approach estimates regression coefficients and uncertainties associated with the covariates in a selected regression model. However, unlike traditional regression methods, the presented approach also estimates the uncertainty associated with the selection of a single "best" model of GPP. In addition, the approach provides an enhanced understanding of how the importance of specific covariates changes with temporal resolutions. An examination of trends in the importance of specific covariates reveals scaling thresholds above or below which covariates become significant in explaining GPP. Results indicate that most sites (especially those with a stronger seasonal cycle) exhibit at least one prominent scaling threshold between daily to 20-day temporal scale. This demonstrates that environmental variables that explain GPP at synoptic scales are different from those that capture its seasonality. At shorter time scales, radiation, temperature, and vapor pressure deficit exert most significant influence on GPP at most examined sites. However, at coarser time scales, the importance of these covariates in explaining GPP declines. Overall, unique best models are identified at most sites at the daily scale, whereas multiple competing models are identified at larger time scales. In addition, the selected models are able to explain a larger fraction of the observed variability for sites exhibiting strong seasonality.

Yadav, V.; Mueller, K. L.; Dragoni, D.; Michalak, A. M.

2010-02-01

399

Electromagnetic force and torque in ponderable media  

E-print Network

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, ExH/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 ponderab...

Mansuripur, Masud

2014-01-01

400

WARPS AND BARS FROM THE EXTERNAL TIDAL TORQUES OF TUMBLING DARK HALOS  

SciTech Connect

The dark matter halos in LAMBDA cold dark matter cosmological simulations are triaxial and highly flattened. In many cases, these triaxial equilibria are also tumbling slowly, typically about their short axes, with periods of order a Hubble time. Halos may therefore exert a slowly changing external torque on spiral galaxies that can affect their dynamical evolution in interesting ways. We examine the effect of the external torques exerted by a tumbling quadrupolar tidal field on the evolution of spiral galaxies using N-body simulations with realistic, disk galaxy models. We measure the amplitude of the external quadrupole moments of dark halos in cosmological simulations and use these to force disk galaxy models in a series of N-body experiments for a range of pattern speeds. We find that the torques are strong enough to induce long-lived transient warps in disks similar to those observed in real spirals and also induce the bar instability at later times in some galaxy models that are otherwise stable for long periods of time in isolation. We also observe forced spiral structure near the edge of the disk where normally self gravity is too weak to be responsible for such a structure. This overlooked influence of dark halos may well be responsible for many of the peculiar aspects of disk galaxy dynamics.

Dubinski, John [Department of Astronomy and Astrophysics, University of Toronto, 50 St. George Street, Toronto, ON M5S 3H4 (Canada); Chakrabarty, Dalia, E-mail: dubinski@astro.utoronto.c, E-mail: dalia.chakrabarty@nottingham.ac.u [School of Physics and Astronomy, University of Nottingham, Nottingham NG7 2RD (United Kingdom)

2009-10-01

401

On the stress and torque tensors in fluid membranes  

E-print Network

We derive the membrane elastic stress and torque tensors using the standard Helfrich model and a direct variational method in which the edges of a membrane are infinitesimally translated and rotated. We give simple expressions of the stress and torque tensors both in the local tangent frame and in projection onto a fixed frame. We recover and extend the results of Capovilla and Guven [J. Phys. A, 2002, \\textbf{35}, 6233], which were obtained using covariant geometry and Noether's theorem: we show that the Gaussian rigidity contributes to the torque tensor and we include the effect of a surface potential in the stress tensor. Many interesting situations may be investigated directly using force and torque balances instead of full energy minimization. As examples, we consider the force exerted at the end of a membrane tubule, membrane adhesion and domain contact conditions.

Jean-Baptiste Fournier

2007-02-12

402

Mechanism and assessment of spin transfer torque (STT) based memory  

E-print Network

When a sufficient current density passes through the MTJ, the spin-polarized current will exert a spin transfer torque to switch the magnetization of the free layer. This is the fundamental of the novel write mechanism in ...

Loh, Iong Ying

2009-01-01

403

40 CFR 90.306 - Dynamometer torque cell calibration.  

Code of Federal Regulations, 2013 CFR

...the indicated torque (IT) for each calibration weight to be used by: IT=Moment Arm (meters) × Calibration Weight (Newtons) (3) Attach each calibration weight specified in § 90.305(b)(2) to the moment arm at the calibration...

2013-07-01

404

Knudsen torque: A rotational mechanism driven by thermal force  

NASA Astrophysics Data System (ADS)

Thermally induced mechanical loading has been shown to have significant effects on micro- and nano-objects immersed in a gas with a nonuniform temperature field. While the majority of existing studies and related applications focus on forces, we investigate the torque, and thus the rotational motion, produced by such a mechanism. Our study has found that a torque can be induced if the configuration of the system is asymmetric. In addition, both the magnitude and the direction of the torque depend highly on the system configuration, indicating the possibility of manipulating the rotational motion via geometrical design. Based on this feature, two types of rotational micromotor that are of practical importance, namely pendulum motor and unidirectional motor, are designed. The magnitude of the torque at Kn =0.5 can reach to around 2nN×?m for a rectangular microbeam with a length of 100?m.

Li, Qi; Liang, Tengfei; Ye, Wenjing

2014-09-01

405

Measurements of mechanical torque acting on a model wind turbine  

NASA Astrophysics Data System (ADS)

A high precision torque converter is developed and calibrated to measure torques on model wind-turbine generators (small DC motor). By multiplying the measured torque and rotor angular velocity, a direct measurement of the extracted power from the wind turbine can be obtained. This direct method is more advantageous compared to the electrical power measured from the model generator, since it avoids contamination by internal friction, and electric and magnetic losses. The torque converter is mounted on a model wind turbine in a 3 by 3 array (3 rows by 3 columns) of wind turbines in the Corrsin wind tunnel. The power coefficients are obtained as a function of the tip speed ratio. Significant difference between the electrical and mechanical powers is observed, which emphasizes on the importance in using the direct mechanical power measurement. Also, the extracted power by the model turbine is found to be comparable with the power estimated from the kinetic energy flux measured using SPIV.

Kang, Hyung-Suk; Cal, Raul B.; Lebron-Bosques, Jose; Castillo, Luciano; Meneveau, Charles

2009-11-01

406

High-performance direct torque control of an induction motor  

Microsoft Academic Search

A novel direct torque control method for an induction motor is presented which is quite different from field-oriented control. Improving the torque response of a large-capacity induction motor using two sets of three-phase inverters and an open-data induction motor is of special concern. Instantaneous voltage vectors applied by an inverter have redundancy characteristics which provide some flexibility for selecting the

I. Takahashi; Y. Ohmori

1989-01-01

407

Torque measurement methods for very high-speed motors  

Microsoft Academic Search

Purpose – The purpose of this paper is to develop a contactless torque measurement methods. The need for low-weight, high-efficiency and high-power density motors has led to an increased research and development activity in the field of very high speed (VHS) motors or generators. Torque measurement methods are inherently linked with the target speed and power of the motor. Therefore,

Pierre-Daniel Pfister; Yves Perriard

2010-01-01

408

Effect of load torque on the stability of overhung rotors  

Microsoft Academic Search

The dynamic stability of overhung flexible rotors subjected to load torques has been studied analytically. Other factors,\\u000a such as external damping, distributed shaft mass, and gyroscopic moments, are considered. For the analyses, the transfer matrix\\u000a is developed to include the effect of the applied torque and then integrated into a computer program to investigate the stability\\u000a of overhung rotor systems

K. B. Yim; Bong-Jo Ryu

2011-01-01

409

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

410

Micro-leakage at the implant-abutment interface with different tightening torques in vitro  

PubMed Central

Objectives This study evaluated the microleakage at the implant/abutment interface of external hexagon (EH) implants and abutments with different amounts of bacteria and tightening torques. Material and Methods A bacterial suspension was prepared to inoculate the implants. The first phase of this study used nine EH implants and abutments that were divided into three groups with different amounts of bacterial suspension (n=3): V0.5: 0.5 µL; V1.0: 1.0 µL e V1.5: 1.5 µL, and tightened to the manufacturer's recommended torque. The second phase of this experiment used 27 assemblies that were similar to those used in the first phase. These samples were inoculated with 0.5 µL of bacterial suspension and divided into three groups (n=9). T10: 10 Ncm; T20: 20 Ncm and T32: 32 Ncm. The samples were evaluated according to the turbidity of the broth every 24 hours for 14 days, and the bacteria viability was tested after that period. The statistical evaluation was conducted by Kruskal-Wallis testing (p<.05). Results During the first phase, groups V1.0 and V1.5 was presented with bacterial contamination in all samples after 24 h. During the second phase, two samples from group T10 and one from T20 presented positive results for bacterial contamination. Different amounts of bacterial solution led to overflow and contamination during the first 24 h of the experiment. The tightening torques did not statistically affect the microleakage in the assemblies. However, the group that was tightened to 32 Ncm torque did not show any bacterial contamination. Conclusion After 14 days of experimentation, the bacteria were proven to remain viable inside the implant internal cavity. PMID:23138747

da SILVA-NETO, Joao Paulo; PRUDENTE, Marcel Santana; CARNEIRO, Thiago de Almeida Prado Naves; NOBILO, Mauro Antonio de Arruda; PENATTI, Mario Paulo Amante; NEVES, Flavio Domingues das

2012-01-01

411

Optimal brake torque distribution for a four-wheeldrive hybrid electric vehicle stability enhancement  

Microsoft Academic Search

Vehicle stability control logic for a four-wheel-drive hybrid electric vehicle is proposed using the regenerative braking of the rear motor and an electrohydraulic brake (EHB). To obtain the optimal brake torque distribution between the regenerative braking and the EHB torque, a genetic algorithm is used. The genetic algorithm calculates the optimal regenerative braking torque and the optimal EHB torque for

D-H Kim; J-M Kim; S-H Hwang; H-S Kim

2007-01-01

412

Manual Detection of Spatial and Temporal Torque Variation through a Rotary Switch  

Microsoft Academic Search

We report three experiments on manual detection of torque variations experienced through a rotary switch. The experiments were designed to investigate whether torque perception was determined by the spatial or by the temporal characteristics of the rotary switch. In Exp. I, manual detection thresholds of torque variation were measured with raised sinusoidal torque profiles that varied in spatial period from

Hong Z. Tan; Shuo Yang; Zygmunt Pizlo; Pietro Buttolo; Matthew Johnston

2008-01-01

413

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

414

On the corotation torque in a radiatively inefficient disk  

E-print Network

We consider the angular momentum exchange at the corotation resonance between a two-dimensional gaseous disk and a uniformly rotating external potential, assuming that the disk flow is adiabatic. We first consider the linear case for an isolated resonance, for which we give an expression of the corotation torque that involves the pressure perturbation, and which reduces to the usual dependence on the vortensity gradient in the limit of a cold disk. Although this expression requires the solution of the hydrodynamic equations, it provides some insight into the dynamics of the corotation region. In the general case, we find an additional dependence on the entropy gradient at corotation. This dependence is associated to the advection of entropy perturbations. These are not associated to pressure perturbations. They remain confined to the corotation region, where they yield a singular contribution to the corotation torque. In a second part, we check our torque expression by means of customized two-dimensional hydrodynamical simulations. In a third part, we contemplate the case of a planet embedded in a Keplerian disk, assumed to be adiabatic. We find an excess of corotation torque that scales with the entropy gradient, and we check that the contribution of the entropy perturbation to the torque is in agreement with the expression obtained from the linear analysis. We finally discuss some implications of the corotation torque expression for the migration of low mass planets in the regions of protoplanetary disks where the flow is radiatively inefficient on the timescale of the horseshoe U-turns.

C. Baruteau; F. Masset

2007-09-17

415

Structural transitions and elasticity from torque measurements on DNA  

NASA Astrophysics Data System (ADS)

Knowledge of the elastic properties of DNA is required to understand the structural dynamics of cellular processes such as replication and transcription. Measurements of force and extension on single molecules of DNA have allowed direct determination of the molecule's mechanical properties, provided rigorous tests of theories of polymer elasticity, revealed unforeseen structural transitions induced by mechanical stresses, and established an experimental and conceptual framework for mechanical assays of enzymes that act on DNA. However, a complete description of DNA mechanics must also consider the effects of torque, a quantity that has hitherto not been directly measured in micromanipulation experiments. We have measured torque as a function of twist for stretched DNA-torsional strain in over- or underwound molecules was used to power the rotation of submicrometre beads serving as calibrated loads. Here we report tests of the linearity of DNA's twist elasticity, direct measurements of the torsional modulus (finding a value ~40% higher than generally accepted), characterization of torque-induced structural transitions, and the establishment of a framework for future assays of torque and twist generation by DNA-dependent enzymes. We also show that cooperative structural transitions in DNA can be exploited to construct constant-torque wind-up motors and force-torque converters.

Bryant, Zev; Stone, Michael D.; Gore, Jeff; Smith, Steven B.; Cozzarelli, Nicholas R.; Bustamante, Carlos

2003-07-01

416

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

417

Nitrogen deposition but not ozone affects productivity and community composition of subalpine grassland after 3 yr of treatment.  

PubMed

A field experiment was established at 2000 m above sea level (asl) in the central Swiss Alps with the aim of investigating the effects of elevated ozone (O(3)) and nitrogen deposition (N), and of their combination, on above-ground productivity and species composition of subalpine grassland. One hundred and eighty monoliths were extracted from a species-rich Geo-Montani-Nardetum pasture and exposed in a free-air O(3)-fumigation system to one of three concentrations of O(3) (ambient, 1.2 x ambient, 1.6 x ambient) and five concentrations of additional N. Above-ground biomass, proportion of functional groups and normalized difference vegetation index (NDVI) were measured annually. After 3 yr of treatment, the vegetation responded to the N input with an increase in above-ground productivity and altered species composition, but without changes resulting from elevated O(3). N input > 10 kg N ha(-1) yr(-1) was sufficient to affect the composition of functional groups, with sedges benefiting over-proportionally. No interaction of O(3) x N was observed, except for NDVI; positive effects of N addition on canopy greenness were counteracted by accelerated leaf senescence in the highest O(3) treatment. The results suggest that effects of elevated O(3) on the productivity and floristic composition of subalpine grassland may develop slowly, regardless of the sensitive response to increasing N. PMID:17635227

Bassin, Seraina; Volk, Matthias; Suter, Matthias; Buchmann, Nina; Fuhrer, Jürg

2007-01-01

418

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

SciTech Connect

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 relating to the rotor structure. The tested values of no-load back electromotive force (emf) and mechanical losses are also presented.

Hsu, J.S.

2004-09-30

419

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

Microsoft Academic Search

Summary  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)

P. Kannus; M. Jiirvinen; M. Lehto

1991-01-01

420

Immediate compensation for variations in self-generated Coriolis torques related to body dynamics and carried objects  

PubMed Central

We have previously shown that the Coriolis torques that result when an arm movement is performed during torso rotation do not affect movement trajectory. Our purpose in the present study was to examine whether torso motion-induced Coriolis and other interaction torques are counteracted during a turn and reach (T&R) movement when the effective mass of the hand is augmented, and whether the dominant arm has an advantage in coordinating intersegmental dynamics as predicted by the dynamic dominance hypothesis (Sainburg RL. Exp Brain Res 142: 241–258, 2002). Subjects made slow and fast T&R movements in the dark to just extinguished targets with either arm, while holding or not holding a 454-g object. Movement endpoints were equally accurate at both speeds, with either hand, and in both weight conditions, but subjects tended to angularly undershoot and produce more variable endpoints for targets requiring greater torso rotation. There were no changes in endpoint accuracy or trajectory deviation over repeated movements. The dominant right arm was more stable in its control of trajectory direction across targets, whereas the nondominant left arm had an improved ability to stop accurately on the target for higher levels of interaction torques. The trajectories to more eccentric targets were straighter when performed at higher speeds but slightly more deviated when subjects held the weight. Subjects did not slow their torso velocity or change the timing of the arm and torso velocities when holding the weight, although there was a slight decrease in their hand velocity relative to the torso. The delay between the onsets of torso and finger movements was almost twice as large for the right arm than the left, suggesting the right arm was better able to account for torso rotation in the arm movement. Holding the weight increased the peak Coriolis torque by 40% at the shoulder and 45% at the elbow and, for the most eccentric target, increased the peak net torque by 12% at the shoulder and 34% at the elbow. In accordance with Sainburg's dynamic dominance hypothesis, the right arm exhibited an advantage for coordinating intersegmental dynamics, showing a more stable finger velocity in relation to the torso across targets, decreasing error variability with movement speed, and more synchronized peaks of finger relative and torso angular velocities in conditions with greater joint torque requirements. The arm used had little effect on the movement path and the magnitude of the joint torques in any of the conditions. These results indicate that compensations for forthcoming Coriolis torque variations take into account the dynamic properties of the body and of external objects, as well as the planned velocities of the torso and arm. PMID:23803330

DiZio, Paul; Lackner, James R.

2013-01-01

421

Asian low-androstenone haplotype on pig chromosome 6 does not unfavorably affect production and reproduction traits.  

PubMed

European pigs that carry Asian haplotypes of a 1.94-Mbp region on pig chromosome 6 have lower levels of androstenone, one of the two main compounds causing boar taint. The objective of our study was to examine potential pleiotropic effects of the Asian low-androstenone haplotypes. A single nucleotide polymorphism marker, rs81308021, distinguishes the Asian from European haplotypes and was used to investigate possible associations of androstenone with production and reproduction traits. Eight traits were available from three European commercial breeds. For the two sow lines studied, a favorable effect on number of teats was detected for the low-androstenone haplotype. In one of these sow lines, a favorable effect on number of spermatozoa per ejaculation was detected for the low-androstenone haplotype. No unfavorable pleiotropic effects were found, which suggests that selection for low-androstenone haplotypes within the 1.94 Mbp would not unfavorably affect the other eight relevant traits. PMID:25262849

Hidalgo, A M; Bastiaansen, J W M; Harlizius, B; Knol, E F; Lopes, M S; de Koning, D J; Groenen, M A M

2014-12-01

422

Production of bromoform and dibromomethane by Giant Kelp: Factors affecting release and comparison to anthropogenic bromine sources  

USGS Publications Warehouse

Macrocystis pyrifera (Giant Kelp), a dominant macroalgal species in southern California, produced 171 ng per g fresh wt (gfwt) per day of CHBr3 and 48 ng gfwt-1 d-1 of CH2Br2 during laboratory incubations of whole blades. Comparable rates were measured during in situ incubations of intact fronds. Release of CHBr3 and CH2Br2 by M. pyrifera was affected by light and algal photosynthetic activity, suggesting that environmental factors influencing kelp physiology can affect halomethane release to the atmosphere. Data from H2O2 additions suggest that brominated methane production during darkness is limited by bromide oxidant supply. A bromine budget constructed for a region of southern California indicated that bromine emitted from the use of CH3Br as a fumigant (1 x 108 g Br yr-1) dominates macroalgal sources (3 x 106 g Br yr-1). Global projections, however, suggest that combined emissions of marine algae (including microalgae) contribute substantial amounts of bromine to the global cycle, perhaps on the same order of magnitude as anthropogenic sources.

Goodwin, K. D.; North, W. J.; Lidstrom, M. E.

1998-01-01

423

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

424

Effects of rotational speed and feed rate on temperature rise, feed force and cutting torque when drilling bovine cortical bone  

NASA Astrophysics Data System (ADS)

Surgical procedures that affect the human bone structure often entail drilling operations of bone. The post-operative evolution of these interventions is conditioned largely by the damage generated during the operation. The aim of this study was to determine clearly the influence of the cutting conditions on temperatures and forces when drilling bovine cortical bone, in the interests of further optimization of cutting conditions to minimize the generated damage. The infrared thermography technique and a piezoelectric dynamometer were employed as measurement devices. It was observed that the main parameter affecting temperatures was the feed per tooth. The temperatures obtained were lower when drilling with high feed per tooth, even though an opposite effect was noticed on the feed force and torque, with an increase of them. From the experimental results, prediction models of temperature rise, feed force and cutting torque were created, in order to predict the response based on the selected cutting conditions.

Soriano, J.; Iriarte, L. M.; Eguren, J. A.; Aristimuño, P.; Garay, A.; Arrazola, P. J.

2012-04-01

425

Large Torque Variations in Two Soft Gamma Repeaters  

E-print Network

We have monitored the pulse frequencies of the two soft gamma repeaters SGR 1806-20 and SGR 1900+14 through the beginning of year 2001 using primarily Rossi X-ray Timing Explorer Proportional Counter Array observations. In both sources, we observe large changes in the spin-down torque up to a factor of ~4, which persist for several months. Using long baseline phase-connected timing solutions as well as the overall frequency histories, we construct torque noise power spectra for each SGR. The power spectrum of each source is very red (power-law slope ~-3.5). The torque noise power levels are consistent with some accreting systems on time scales of ~1 year, yet the full power spectrum is much steeper in frequency than any known accreting source. To the best of our knowledge, torque noise power spectra with a comparably steep frequency dependence have only been seen in young, glitching radio pulsars (e.g. Vela). The observed changes in spin-down rate do not correlate with burst activity, therefore, the physical mechanisms behind each phenomenon are also likely unrelated. Within the context of the magnetar model, seismic activity cannot account for both the bursts and the long-term torque changes unless the seismically active regions are decoupled from one another.

Peter M. Woods; Chryssa Kouveliotou; Ersin Gougus; Mark H. Finger; Jean Swank; Craig B. Markwardt; Kevin Hurley; Michiel van der Klis

2001-09-20

426

Nanomagnonic devices based on the spin-transfer torque  

NASA Astrophysics Data System (ADS)

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.

Urazhdin, S.; Demidov, V. E.; Ulrichs, H.; Kendziorczyk, T.; Kuhn, T.; Leuthold, J.; Wilde, G.; Demokritov, S. O.

2014-07-01

427

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

428

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

429

Large Torque Variations in Two Soft Gamma Repeaters  

NASA Technical Reports Server (NTRS)

We have monitored the pulse frequencies of the two soft gamma repeaters SGR 1806-20 and SGR 1900+14 through the beginning of year 2001 using primarily Rossi X-Ray Timing Explorer Proportional Counter Array observations. In both sources, we observe large changes in the spin-down torque up to a factor of approximately 4, which persist for several months. Using long-baseline phase-connected timing solutions as well as the overall frequency histories, we construct torque noise power spectra for each SGR (Soft Gamma Repeater). The power spectrum of each source is very red (power-law slope is approximately -3.5). The torque noise power levels are consistent with some accreting systems on timescales of approximately 1 yr, yet the full power spectrum is much steeper in frequency than any known accreting source. To the best of our knowledge, torque noise power spectra with a comparably steep frequency dependence have been seen only in young, glitching radio pulsars (e.g., Vela). The observed changes in spin-down rate do not correlate with burst activity; therefore, the physical mechanisms behind each phenomenon are also likely unrelated. Within the context of the magnetar model, seismic activity can not account for both the bursts and the long-term torque changes unless the seismically active regions are decoupled from one another.

Woods, Peter M.; Kouveliotou, Chryssa; Gogus, Ersin; Finger, Mark H.; Swank, Jean; Markwardt, Craig B.; Hurley, Kevin; vanderKlis, Michiel

2002-01-01

430

Does body size of dairy cows, at constant ratio of maintenance to production requirements, affect productivity in a pasture-based production system?  

PubMed

This study compared productivity of dairy cows with different body weight (BW), but a constant ratio of maintenance to production requirements in their first lactation, in a pasture-based production system with spring calving. Two herds, Herd L (13 and 14 large cows in 2003 and 2004 respectively; average BW after calving, 721 kg) and Herd S (16 small cows in both years; 606 kg) [Correction added after online publication 14 January 2011: 16 small cows in both years; 621 kg was changed to 16 small cows in both years; 606 kg], all in their second or following lactations, were each allocated 6 ha of pasture and rotationally grazed on 10 parallel paddocks with equal herbage offer and nutritional values. Winter hay, harvested from the same pastures, was offered ad libitum in the indoor periods in a tied stall barn. Each herd received, per lactation and year, approximately 2000 kg dry matter (DM) of concentrates and of fodder beets, equally distributed to every individual. Indoors, the L-cows ingested more DM than the S-cows (18.7 vs. 16.3 kg DM/cow per day; p < 0.01), but DM intake per 100 kg of metabolic BW was similar (13.0 vs. 13.1 kg DM/cow per day). Estimates based on the n-alkane technique gave similar results on pasture (17.9 vs. 15.5 kg DM/cow per day; p < 0.001). Roughage intakes per 100 kg of metabolic BW, at 13.5 kg DM/cow per day, were similar. Mean annual yield of energy-corrected milk (ECM)/ha was slightly higher for the S-herd than the L-herd (13,026 vs. 12,284 kg) but was associated with a higher stocking rate (on average +20%) for the S-herd. Feed conversion efficiency (1.2 vs. 1.3 kg ECM/kg DM intake) and overall milk production efficiency (45.3 vs. 47.3 kg ECM/kg metabolic BW) were similar in L- and S-cows. Thus, both dairy cow types were equally efficient in utilising pasture-based forage. PMID:21114551

Hofstetter, P; Steiger Burgos, M; Petermann, R; Münger, A; Blum, J W; Thomet, P; Menzi, H; Kohler, S; Kunz, P

2011-12-01

431

Litter Moisture and Footpad Dermatitis as Affected by Diets Formulated on an All-Vegetable Basis or Having the Inclusion of Poultry By-Product  

Microsoft Academic Search

SUMMARY Chicken feet (paws) are valuable products in the Asian market. Foot dermatitis, mostly caused by litter condition, can affect the foot skin tissue leading to downgrades and reduced market value. In this study, a diet having animal by-products was compared with 2 all-vegetable diets formulated with corn, soybean meal, and toasted soybean with or without corn gluten meal. A

G. Eichner; S. L. Vieira; C. A. Torres; J. L. B. Coneglian; D. M. Freitas; O. A. Oyarzabal

432

Inactivation of ccpA and aeration affect growth, metabolite production and stress tolerance in Lactobacillus plantarum WCFS1.  

PubMed

The growth of Lactobacillus plantarum WCFS1 and of its ?ccpA ery mutant, WCFS1-2, was compared in batch fermentations in a complex medium at controlled pH (6.5) and temperature (30°C) with or without aeration, in order to evaluate the effect of ccpA inactivation and aeration on growth, metabolism and stress resistance. Inactivation of ccpA and, to a lesser extent, aeration, significantly affected growth, expression of proteins related to pyruvate metabolism and stress, and tolerance to heat, oxidative and cold/starvation stresses. The specific growth rate of the mutant was ca. 60% of that of the wild type strain. Inactivation of ccpA and aerobic growth significantly affected yield and production of lactic and acetic acid. Stationary phase cells were more stress tolerant than exponential phase cells with little or no effect of inactivation of ccpA or aeration. On the other hand, for exponential phase cells inactivation of ccpA impaired both heat stress and cold/starvation stress, but increased oxidative stress tolerance. For both strains, aerobically grown cells were more tolerant of stresses. Evidence for entry in a viable but non-culturable status upon prolonged exposure to cold and starvation was found. Preliminary results of a differential proteomic study further confirmed the role of ccpA in the regulation of carbohydrate catabolism and class I stress response genes and allow to gain further insight on the role of this pleiotropic regulator in metabolism and stress. This is the first study in which the impact of aerobic growth on stress tolerance of L. plantarum is evaluated. Although aerobic cultivation in batch fermentations does not improve growth it does improve stress tolerance, and may have significant technological relevance for the preservation of starter and probiotic cultures. PMID:22326142

Zotta, Teresa; Ricciardi, Annamaria; Guidone, Angela; Sacco, Margherita; Muscariello, Lidia; Mazzeo, Maria Fiorella; Cacace, Giuseppina; Parente, Eugenio

2012-04-01

433

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

434

Water availability and calcium propionate affect fungal population and aflatoxins production in broiler finisher feed during storage.  

PubMed

The aim of this study was to investigate the effects of calcium propionate, water activity (aw) and incubation time on the total fungal count and aflatoxins B1 (AFB1), B2 (AFB2), G1 (AFG1) and G2 (AFG2) production in the broiler finisher feed. The feed was added with calcium propionate (5 g kg(-1)), adjusted to 0.85, 0.90 and 0.95 aw and stored for 28 days at 25°C, analysing for mould growth and aflatoxins production every 7 days. Analysis of variance indicated that all the factors (preservative, aw and storage time) alone and in combination significantly (p < 0.001) affected the total fungal count and aflatoxins production in the feed. Minimum total fungal counts (1.99 × 10(2) CFU g(-1)) were observed in calcium propionate feed at 0.85 aw on day 1 and the highest (4.36 × 10(9) CFUs g(-1)) in control sample at 0.95 aw on day 28 of storage. During the storage period, AFB1 content in control samples increased from 11.35 to 73.44, from 11.58 to 81.81 and from 11.54 to 102.68 ng g(-1), whereas in preserved feed the content of B1 increased from 11.47 to 37.83, from 11.54 to 49.07 and from 11.20 to 53.14 ng g(-1) at 0.85, 0.90 and 0.95 aw, respectively. Similar patterns were noted for AFB2, AFG1 and AFG2 contents. All the aflatoxins readily increased over storage time; however, the increase was much slower in preserved feed that contained a lower amount of available water. This study reveals that calcium propionate addition to poultry litter along with water activity amelioration is an effective tool for controlling mould incidence and aflatoxin production in poultry feed. PMID:25290990

Alam, Sahib; Shah, Hamid Ullah; Khan, Nazir Ahmad; Zeb, Alam; Shah, Abdul Sattar; Magan, Naresh

2014-11-01

435

Mechanics of Re-Torquing in Bolted Flange Connections  

NASA Technical Reports Server (NTRS)

It has been widely accepted that the phenomenon of time-dependent loosening of flange connections is a strong consequence of the viscous nature of the compression seal material. Characterizing the coupled interaction between gasket creep and elastic bolt stiffness has been useful in predicting conditions that facilitate leakage. Prior advances on this sub-class of bolted joints has lead to the development of (1) constitutive models for elastomerics, (2) initial tightening strategies, (3) etc. The effect of re-torque, which is a major consideration for typical bolted flange seals used on the Space Shuttle fleet, has not been fully characterized, however. The current study presents a systematic approach to characterizing bolted joint behavior as the consequence of sequentially applied torques. Based on exprimenta1 and numerical results, the optimal re-torquing parameters have been identified that allow for the negligible load loss after pre-load application

Gordon, Ali P.; Drilling Brian; Weichman, Kyle; Kammerer, Catherine; Baldwin, Frank

2010-01-01

436

Advanced torque converters for robotics and space applications  

NASA Technical Reports Server (NTRS)

This report describes the results of the evaluation of a novel torque converter concept. Features of the concept include: (1) automatic and rapid adjustment of effective gear ratio in response to changes in external torque (2) maintenance of output torque at zero output velocity without loading the input power source and (3) isolation of input power source from load. Two working models of the concept were fabricated and tested, and a theoretical analysis was performed to determine the limits of performance. It was found that the devices are apparently suited to certain types of tool driver applications, such as screwdrivers, nut drivers and valve actuators. However, quantiative information was insufficient to draw final conclusion as to robotic applications.

1985-01-01

437

Magnetic Torque of Microfabricated Elements and Magnetotactic Bacteria  

E-print Network

We present a thorough theoretical analysis of the magnetic torque on microfabricated elements with dimensions in the range of 100 to 500 {\\mu}m and magneto-somes of magnetotactic bacteria of a few {\\mu}m length. We derive simple equations for field dependent torque and magnetic shape anisotropy that can be readily used to replace the crude approximations commonly used. We illustrate and verify the theory on microfabricated elements and magnetotactic bacteria, by field depedent torque magnetometry and by observing their rotation in water under application of a rotating magnetic field. The maximum rotation frequency of the largest microfabricated elements agrees within error boundaries with theory. For smaller, and especially thinner, elements the measured frequencies are a factor of three to four too low. We suspect this is caused by incomplete saturation of the magnetisation in the elements, which is not incorporated in our model. The maximum rotation frequency of magnetotactic bacteria agrees with our model ...

Zondervan, Lars; Khalil, Islam S M; Pichel, Marc P; Misra, Sarthak; Abelmann, Leon

2014-01-01

438

Radiation torque on nonspherical particles in the transition matrix formalism  

NASA Astrophysics Data System (ADS)

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.

Borghese, Ferdinando; Denti, Paolo; Saija, Rosalba; Iatì, Maria A.

2006-10-01

439

Spin transfer torque effects in magnetic nanostructures  

NASA Astrophysics Data System (ADS)

Spin transfer torque (STT) effects have been studied using a point-contact spin injection technique in (1) magnetic trilayers, (2) a single exchange-biased ferromagnetic layer, and (3) magnetic granular solids. In the point-contact spin injection, a sharp metallic tip is in contact with a thin film structure. The high current density (e.g. 10 8 A/cm²) required for the STT effects is achieved by concentrating a current of a few milli-amperes into a point contact with a cross section less than 100 nanometers. Spin (polarized electrons) is injected into the contact region via a spin polarizer, a ferromagnetic film underneath the film structure. Resistance and differential resistance of the contact as a function of the current in the contact are measured at the same time using a lock-in technique. Steps in the resistance and spikes in the differential resistance indicate non-collinear spin structures are induced by the STT effect. The non-collinear spin structures are verified by the magnetoresistance of the contact with a small current without causing any STT effect. The experiments are carried out at cryogenic temperatures obtained by a liquid helium dewar and in magnetic fields up to 9 Tesla provided by a superconductor magnet. In magnetic trilayers such as Co/Cu/Co film where the STT effect is an inverse effect of the giant magnetoresistance (GMR) effect, a magnetic bit can be reversibly written by a spin polarized current injected through a point contact into the continuous film. The magnetic states written depend on the polarity of the injection currents, and remain stable at room temperature. The reversible writing can be achieved for a wide range of contact resistances with a well-defined voltage for the reversal. With the assistance of the exchange coupling of an antiferromagnetic CoO layer, a nanodomain has been created and manipulated by the inhomogeneous current density within a ferromagnetic Co layer, showing hysteretic switching loops at low fields. At high magnetic fields, the hysteretic loops collapse to one polarity of the current and result in spikes in the differential resistance curves. There is no GMR in the single film geometry, the effect is, therefore, a new type of the STT effect which is the inverse effect of the domain wall magnetoresistance (DMR) effect. The resistance steps at high fields have been shown mostly due to the magnetization reversal while the spin precession exists in the vicinity of the reversal current. Surprisingly, no STT effects have been observed in magnetic granular solids Co-Ag at low fields despite the existence of the GMR effect. However, large resistance change has been observed at high fields with high currents. It turns out that the usual high resistance state of a granular solid, the random magnetization state, cannot be obtained by the STT effect. An antiparallel spin structure is rather induced at high fields. This spin structure, which is unattainable by any other means, generates a spectacular magnetoresistance of 400%, the largest ever reported in any metallic systems. The characteristics of the STT effect in granular solids has been studied in great detail both at the liquid helium temperature and 160 K, and has found to be much different from those previously observed in multilayers and single layers. This work has been carried out under the guidance of the author's thesis advisor, Prof. Chia-Ling Chien.

Chen, Tingyong

440

Torque Generation of Enterococcus hirae V-ATPase.  

PubMed

V-ATPase (VoV1) converts the chemical free energy of ATP into an ion-motive force across the cell membrane via mechanical rotation. This energy conversion requires proper interactions between the rotor and stator in VoV1 for tight coupling among chemical reaction, torque generation, and ion transport. We developed an Escherichia coli expression system for Enterococcus hirae VoV1 (EhVoV1) and established a single-molecule rotation assay to measure the torque generated. Recombinant and native EhVoV1 exhibited almost identical dependence of ATP hydrolysis activity on sodium ion and ATP concentrations, indicating their functional equivalence. In a single-molecule rotation assay with a low load probe at high ATP concentration, EhVoV1 only showed the "clear" state without apparent backward steps, whereas EhV1 showed two states, "clear" and "unclear." Furthermore, EhVoV1 showed slower rotation than EhV1 without the three distinct pauses separated by 120° that were observed in EhV1. When using a large probe, EhVoV1 showed faster rotation than EhV1, and the torque of EhVoV1 estimated from the continuous rotation was nearly double that of EhV1. On the other hand, stepping torque of EhV1 in the clear state was comparable with that of EhVoV1. These results indicate that rotor-stator interactions of the Vo moiety and/or sodium ion transport limit the rotation driven by the V1 moiety, and the rotor-stator interactions in EhVoV1 are stabilized by two peripheral stalks to generate a larger torque than that of isolated EhV1. However, the torque value was substantially lower than that of other rotary ATPases, implying the low energy conversion efficiency of EhVoV1. PMID:25258315

Ueno, Hiroshi; Minagawa, Yoshihiro; Hara, Mayu; Rahman, Suhaila; Yamato, Ichiro; Muneyuki, Eiro; Noji, Hiroyuki; Murata, Takeshi; Iino, Ryota

2014-11-01

441

Analysis and simulation of a torque assist automated manual transmission  

NASA Astrophysics Data System (ADS)

The paper presents the kinematic and dynamic analysis of a power-shift automated manual transmission (AMT) characterised by a wet clutch, called assist clutch (ACL), replacing the fifth gear synchroniser. This torque assist mechanism becomes a torque transfer path during gearshifts, in order to overcome a typical dynamic problem of the AMTs, that is the driving force interruption. The mean power contributions during gearshifts are computed for different engine and ACL interventions, thus allowing to draw considerations useful for developing the control algorithms. The simulation results prove the advantages in terms of gearshift quality and ride comfort of the analysed transmission.

Galvagno, E.; Velardocchia, M.; Vigliani, A.

2011-08-01

442

Kinetic Energy Principle And Neoclassical Toroidal Torque In Tokamaks  

SciTech Connect

It is shown that when tokamaks are perturbed the kinetic energy principle is closely related to the neoclassical toroidal torque by the action invariance of particles. Especially when tokamaks are perturbed from scalar pressure equilibria, the imaginary part of the potential energy in the kinetic energy principle is equivalent to the toroidal torque by the Neoclassical Toroidal Viscosity (NTV). A unified description therefore should be made for both physics. It is also shown in this case that the potential energy operator can be self-adjoint and thus the stability calculation can be simplified by minimizing the potential energy

Jong-Kyu Park

2011-11-07

443

Low writing energy and sub nanosecond spin torque transfer switching of in-plane magnetic tunnel junction for spin torque transfer random access memory  

NASA Astrophysics Data System (ADS)

This work investigated in-plane MgO-based magnetic tunnel junctions (MTJs) for the application of spin torque transfer random access memory (STT-RAM). The MTJ in this work had an resistance area product (RA) = 4.3 ?.?m2, tunneling magnetoresistance ratio ˜135%, thermal stability factor ?(H)=68 (by field measurement), and ?(I) = 50 (by current measurement). The optimal writing energy was found to be 0.286 pJ per bit at 1.54 ns for antiparallel (AP) state to parallel (P) state switching, and 0.706 pJ per bit at 0.68 ns for P state to AP state switching. Ultra fast spin torque transfer (STT) switching was also observed in this sample at 580 ps (AP to P) and 560 ps (P to AP). As a result, 0.6-1.3 GHz was determined to be the optimal writing rate from writing energy consumption of view. These results show that in-plane MgO MTJs are still a viable candidate as the fast memory cell for STT-RAM.

Zhao, H.; Lyle, A.; Zhang, Y.; Amiri, P. K.; Rowlands, G.; Zeng, Z.; Katine, J.; Jiang, H.; Galatsis, K.; Wang, K. L.; Krivorotov, I. N.; Wang, J.-P.

2011-04-01

444

Spin transfer torque in antiferromagnetic spin valves: From clean to disordered regimes  

NASA Astrophysics Data System (ADS)

Current-driven spin torques in metallic spin valves composed of antiferromagnets are theoretically studied using the nonequilibrium Green's function method implemented on a tight-binding model. We focus our attention on G-type and L-type antiferromagnets in both clean and disordered regimes. In such structures, spin torques can either rotate the magnetic order parameter coherently (coherent torque) or compete with the internal antiferromagnetic exchange (exchange torque). We show that, depending on the symmetry of the spin valve, the coherent and exchange torques can either be in the plane, ?n×(q×n) or out of the plane ?n×q, where q and n are the directions of the order parameter of the polarizer and the free antiferromagnetic layers, respectively. Although disorder conserves the symmetry of the torques, it strongly reduces the torque magnitude, pointing out the need for momentum conservation to ensure strong spin torque in antiferromagnetic spin valves.

Saidaoui, Hamed Ben Mohamed; Manchon, Aurelien; Waintal, Xavier

2014-05-01

445

Torque characteristics of a 122-centimeter butterfly valve with a hydro/pneumatic actuator  

NASA Technical Reports Server (NTRS)

Actuating torque data from field testing of a 122-centimeter (48 in.) butterfly valve with a hydro/pneumatic actuator is presented. The hydraulic cylinder functions as either a forward or a reverse brake. Its resistance torque increases when the valve speeds up and decreases when the valve slows down. A reduction of flow resistance in the hydraulic flow path from one end of the hydraulic cylinder to the other will effectively reduce the hydraulic resistance torque and hence increase the actuating torque. The sum of hydrodynamic and friction torques (combined resistance torque) of a butterfly valve is a function of valve opening time. An increase in the pneumatic actuating pressure will result in a decrease in both the combined resistance torque and the actuator opening torque; however, it does shorten the valve opening time. As the pneumatic pressure increases, the valve opening time for a given configuration approaches an asymptotical value.

Lin, F. N.; Moore, W. I.; Lundy, F. E.

1981-01-01

446

Depressing the torque vibrations of turbine blades using virtual inertia  

Microsoft Academic Search

Based on an electromechanical analogy, a turbine mechanical system can be transferred into an equivalent electrical circuit, allowing a phasor diagram to be used to evaluate the turbine shaft and blade responses to the electromagnetic (E\\/M) torque disturbance. After investigating six practical large-scale turbine units using frequency scanning, the dynamics of the blades were always found to be sensitive to

Chi-Hshiung Lin; Ta-Peng Tsao

2002-01-01

447

Drive torque actuation in active surge control of centrifugal compressors  

E-print Network

Drive torque actuation in active surge control of centrifugal compressors Jan Tommy Gravdahl , Olav to active surge control is presented for a centrifugal compressor driven by an electrical motor. The main compressor driven by an electrical motor. 1 Background Surge is an unstable operation mode of centrifugal

Gravdahl, Jan Tommy

448

Tidal torque induced by orbital decay in compact object binaries  

NASA Astrophysics Data System (ADS)

As we observe in the moon-earth system, tidal interactions in binary systems can lead to angular momentum exchange. The presence of viscosity is generally regarded as the condition for such transfer to happen. In this paper, we show how the orbital evolution can cause a persistent torque between the binary components, even for inviscid bodies. This preferentially occurs at the final stage of coalescence of compact binaries, when the orbit shrinks successively by gravitational waves and plunging on a time-scale shorter than the viscous time-scale. The total orbital energy transferred to the secondary by this torque is ˜10-2 of its binding energy. We further show that this persistent torque induces a differentially rotating quadrupolar perturbation. Specializing to the case of a secondary neutron star, we find that this non-equilibrium state has an associated free energy of 1047-1048 erg, just prior to coalescence. This energy is likely stored in internal fluid motions, with a sizeable amount of differential rotation. By tapping this free energy reservoir, a pre-existing weak magnetic field could be amplified up to a strength of ?1015 G. Such a dynamically driven tidal torque can thus recycle an old neutron star into a magnetar, with possible observational consequences at merger.

Dall'Osso, Simone; Rossi, Elena M.

2013-01-01

449

Theory comparison and numerical benchmarking on neoclassical toroidal viscosity torque  

NASA Astrophysics Data System (ADS)

Systematic comparison and numerical benchmarking have been successfully carried out among three different approaches of neoclassical toroidal viscosity (NTV) theory and the corresponding codes: IPEC-PENT is developed based on the combined NTV theory but without geometric simplifications [Park et al., Phys. Rev. Lett. 102, 065002 (2009)]; MARS-Q includes smoothly connected NTV formula [Shaing et al., Nucl. Fusion 50, 025022 (2010)] based on Shaing's analytic formulation in various collisionality regimes; MARS-K, originally computing the drift kinetic energy, is upgraded to compute the NTV torque based on the equivalence between drift kinetic energy and NTV torque [J.-K. Park, Phys. Plasma 18, 110702 (2011)]. The derivation and numerical results both indicate that the imaginary part of drift kinetic energy computed by MARS-K is equivalent to the NTV torque in IPEC-PENT. In the benchmark of precession resonance between MARS-Q and MARS-K/IPEC-PENT, the agreement and correlation between the connected NTV formula and the combined NTV theory in different collisionality regimes are shown for the first time. Additionally, both IPEC-PENT and MARS-K indicate the importance of the bounce harmonic resonance which can greatly enhance the NTV torque when E ×B drift frequency reaches the bounce resonance condition.

Wang, Zhirui; Park, Jong-Kyu; Liu, Yueqiang; Logan, Nikolas; Kim, Kimin; Menard, Jonathan E.

2014-04-01

450

Self-similar spherical collapse with tidal torque  

SciTech Connect

N-body simulations have revealed a wealth of information about dark matter halos; however, their results are largely empirical. Using analytic means, we attempt to shed light on simulation results by generalizing the self-similar secondary infall model to include tidal torque. In this first of two papers, we describe our halo formation model and compare our results to empirical mass profiles inspired by N-body simulations. Each halo is determined by four parameters. One parameter sets the mass scale and the other three define how particles within a mass shell are torqued throughout evolution. We choose torque parameters motivated by tidal torque theory and N-body simulations and analytically calculate the structure of the halo in different radial regimes. We find that angular momentum plays an important role in determining the density profile at small radii. For cosmological initial conditions, the density profile on small scales is set by the time rate of change of the angular momentum of particles as well as the halo mass. On intermediate scales, however, {rho}{proportional_to}r{sup -2}, while {rho}{proportional_to}r{sup -3} close to the virial radius.

Zukin, Phillip; Bertschinger, Edmund [Department of Physics, MIT, 77 Massachusetts Avenue, Cambridge, Massachusetts 02139 (United States)

2010-11-15

451

Friction torque in grease lubricated thrust ball bearings  

Microsoft Academic Search

Thrust ball bearings lubricated with several different greases were tested on a modified Four-Ball Machine, where the Four-Ball arrangement was replaced by a bearing assembly. The friction torque and operating temperatures in a thrust ball bearing were measured during the tests. At the end of each test a grease sample was analyzed through ferrographic techniques in order to quantify and

Tiago Cousseau; Beatriz Graça; Armando Campos; Jorge Seabra

2011-01-01

452

Torque Measurement and Ekman Effects in Taylor-Couette Flow  

NASA Astrophysics Data System (ADS)

Magnetorotational instabilities (MRI) are widely viewed to be a key angular-momentum transport mechanism in magnetized accretion discs; however, they have not yet been realized in a laboratory setting. An experiment, currently under way, will use liquid gallium to produce MRI in a Couette flow geometry. In order for MRI to be observed, it is necessary to have an accurate method of characterizing the fluid behavior and of differentiating between MRI-induced behavior and hydrodynamic behavior. One such method is to measure the fluid torque coupling between the inner and outer walls of a Couette flow. This coupling was observed by measuring the reaction torque exerted on the outer-cylinder driving-motor as both inner- and outer-cylinder rotation speeds were varied. This was performed alternately using air and water in the cell to establish mechanical and hydrodynamic background measurement methods for use in future MRI experiments. It was found that outward angular momentum flux and torque coupling were much stronger when inner-cylinder rotation rates were greater than the outer-cylinder rotation rates. Torque coupling measurements were compared with those expected for an Ekman-type transport mechanism based on hydrodynamic simulations.

Hays, R.; Ji, H.; Chen, F.

2003-10-01

453

Instantaneous frictional torque components in a diesel engine  

Microsoft Academic Search

This paper discusses the instantaneous frictional torque (IFT) of many components of a single cylinder diesel engine determined by considering the forces acting on each component and the resulting change in the angular velocity. The IFT for the basic system, consisting of the crankshaft with the flywheel and oil pump, was first determined. The effect of adding each of the

N. A. Henein; A. Fragoulis; W. Bryzik

1989-01-01

454

Ultrasonic resonant piezoelectric actuator with intrinsic torque measurement.  

PubMed

Piezoelectric ultrasonic actuators are widely used in small-scale actuation systems, in which a closed-loop position control is usually utilized. To save an additional torque sensor, the intrinsic measurement capabilities of the piezoelectric material can be employed. To prove feasibility, a motor setu