Sample records for affects torque production

  1. Torque production in permanent-magnet synchronous motors

    Microsoft Academic Search

    J. De La Ree; N. Boules

    1989-01-01

    An analytical method was developed to determine cogging as well as commutating torque in permanent-magnet machines of both buried and surface-mounted magnet types. A detailed analysis of the torque production in a permanent magnet synchronous motor drive with rectangular current excitation is presented. The effect of skewing is considered. The proposed method takes advantage of the knowledge of the flux

  2. Contraction history affects the in vivo quadriceps torque-velocity relationship in humans

    Microsoft Academic Search

    Levente Rácz; Sándor Béres; Tibor Hortobágyi; József Tihanyi

    2002-01-01

    .   We hypothesized that the history of contraction would affect the in vivo quadriceps torque-velocity relationship. We examined\\u000a the quadriceps torque-velocity relationship of the human knee extensors at the descending and ascending limb of the torque-position\\u000a relationship by initiating the knee extension at a knee angle position of 1.39 rad (80) or 0.87 rad (50) over a 0.52 rad\\u000a (30) range of motion

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

    PubMed Central

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

    2013-01-01

    [Purpose] This research analyzed how seat distance and gender affect maximal torque and muscle strength when driving to present base data for the optimal driving posture. [Subjects and Methods] The subjects were 27 college students in their 20's, 15 males and 12 females. After had been measured, the subjects sat in front of a steering wheel with the distance between the steering wheel and the seat set in turns. at 50, 70, and 90% their arm length, and the maximal torque and muscle strength were measured. [Results] Both the maximal torque and muscle strength were found to be greater in male subjects than female subjects whether they turned the steering wheel clockwise or counterclockwise. The difference was big enough to be statistically significant. Maximal torque was greatest when the seat distance was 50% of arm length, whether turning the steering wheel clockwise or counterclockwise. There were statistically significant differences in maximal torque between seat distances of 50 and 70% and 90% of the arm length. Muscle strength, in contrast, was found to be the greatest at a seat distance of 70% of arm length. [Conclusion] We conclude that greater torque can be obtained when the steering wheel is nearer the seat while greater muscle strength can be obtained when the seat distance from the steering wheel is 70% of the arm length. PMID:24259937

  4. The fatigue effect of a simulated futsal match protocol on isokinetic knee torque production.

    PubMed

    Dal Pupo, Juliano; Detanico, Daniele; Santos, Saray Giovana Dos

    2014-11-01

    The objective of this study was to investigate the effects of a simulated futsal match protocol on isokinetic knee torque production. Twenty-one young futsal players participated in this study and performed a futsal-specific protocol comprising two blocks of 20-minute activities to simulate the match demands. At pre-protocol, half-time, and post-protocol, the concentric and eccentric isokinetic peak torque of the knee flexor and extensor muscles, the angle of peak torque, and the conventional and functional torque ratios were assessed. ANOVA was used to compare the variables (significance level p <  0.05). A decrease of knee flexor and extensor eccentric torque and knee flexor concentric torque was found, in which the pre-protocol levels were higher than those at half-time, with both being larger than those at post-protocol. The knee extensor concentric torque reduced at half-time. The angle of eccentric torque of knee flexors increased, and the conventional and functional torque ratios decreased at post-protocol. In conclusion, the protocol produced a time-dependent reduction of knee flexor and extensor torque in both concentric and eccentric actions. These findings suggested a possible impairment of performance and the emergence of risk factors for hamstring strains during a futsal match. PMID:25420210

  5. Measurement of upper extremity torque production and its relationship to throwing speed in the competitive athlete.

    PubMed

    Bartlett, L R; Storey, M D; Simons, B D

    1989-01-01

    This study was conducted to establish whether or not a correlation exists between peak torque production of upper extremity (UE) musculature and throwing speed. Eleven professional baseball players were tested for upper extremity peak torque production using a Cybex II Isokinetic Dynamometer. Throwing speed was measured with a radar gun. Results of statistical analysis performed on the data indicate a correlation between shoulder adductors and throwing speed. PMID:2929844

  6. The framework of product affection

    Microsoft Academic Search

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

    2009-01-01

    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

  7. How Joint Torques Affect Hamstring Injury Risk in Sprinting Swing–Stance Transition

    PubMed Central

    SUN, YULIANG; WEI, SHUTAO; ZHONG, YUNJIAN; FU, WEIJIE; LI, LI; LIU, YU

    2015-01-01

    ABSTRACT Purpose The potential mechanisms of hamstring strain injuries in athletes are not well understood. The study, therefore, was aimed at understanding hamstring mechanics by studying loading conditions during maximum-effort overground sprinting. Methods Three-dimensional kinematics and ground reaction force data were collected from eight elite male sprinters sprinting at their maximum effort. Maximal isometric torques of the hip and knee were also collected. Data from the sprinting gait cycle were analyzed via an intersegmental dynamics approach, and the different joint torque components were calculated. Results During the initial stance phase, the ground reaction force passed anteriorly to the knee and hip, producing an extension torque at the knee and a flexion torque at the hip joint. Thus, the active muscle torque functioned to produce flexion torque at the knee and extension torque at the hip. The maximal muscle torque at the knee joint was 1.4 times the maximal isometric knee flexion torque. During the late swing phase, the muscle torque counterbalanced the motion-dependent torque and acted to flex the knee joint and extend the hip joint. The loading conditions on the hamstring muscles were similar to those of the initial stance phase. Conclusions During both the initial stance and late swing phases, the large passive torques at both the knee and hip joints acted to lengthen the hamstring muscles. The active muscle torques generated mainly by the hamstrings functioned to counteract those passive effects. As a result, during sprinting or high-speed locomotion, the hamstring muscles may be more susceptible to high risk of strain injury during these two phases. PMID:24911288

  8. Factors affecting consumer perceptions on product safety

    Microsoft Academic Search

    Alan Ching Biu Tse

    1999-01-01

    Examines how perceived product safety may be affected by such product-related factors as price, brand name, store name, promotion channels, source credibility, country of origin, nature of product testing authority and warranty. Shows that perceived product safety was significantly affected by all of the variables mentioned above. Implies that, by carefully manipulating these variables in formulating marketing strategies, managers can

  9. Affective Productions of Mathematical Experience

    ERIC Educational Resources Information Center

    Walshaw, Margaret; Brown, Tony

    2012-01-01

    In underscoring the affective elements of mathematics experience, we work with contemporary readings of the work of Spinoza on the politics of affect, to understand what is included in the cognitive repertoire of the Subject. We draw on those resources to tell a pedagogical tale about the relation between cognition and affect in settings of…

  10. FACTORS AFFECTING ANFO FUMES PRODUCTION

    Microsoft Academic Search

    James H. Rowland III; Richard Mainiero

    For many years there have been small scale tests available for evaluating the toxic fumes production by cap- sensitive explosives (DOT Class 1.1), but these could not be used with blasting agents due to the large charge sizes and heavy confinement required for proper detonation. Considering the extensive use of blasting agents in construction and mining, there is a need

  11. Provocative mechanical tests of the peripheral nervous system affect the joint torque-angle during passive knee motion.

    PubMed

    Andrade, R J; Freitas, S R; Vaz, J R; Bruno, P M; Pezarat-Correia, P

    2015-06-01

    This study aimed to determine the influence of the head, upper trunk, and foot position on the passive knee extension (PKE) torque-angle response. PKE tests were performed in 10 healthy subjects using an isokinetic dynamometer at 2°/s. Subjects lay in the supine position with their hips flexed to 90°. The knee angle, passive torque, surface electromyography (EMG) of the semitendinosus and quadriceps vastus medialis, and stretch discomfort were recorded in six body positions during PKE. The different maximal active positions of the cervical spine (neutral; flexion; extension), thoracic spine (neutral; flexion), and ankle (neutral; dorsiflexion) were passively combined for the tests. Visual analog scale scores and EMG were unaffected by body segment positioning. An effect of the ankle joint was verified on the peak torque and knee maximum angle when the ankle was in the dorsiflexion position (P?torque (P?torque when the cervical and thoracic spines were flexed (P?torque-angle response since different positions of head, upper trunk, and foot induce dissimilar knee mechanical responses during passive extension. PMID:24941915

  12. A novel, single stator dual PM rotor, synchronous machine: Topology, circuit model, controlled dynamics simulation and 3D FEM analysis of torque production

    Microsoft Academic Search

    Ion Boldea; Marcel Topor; Fabrizio Marignetti; Sorin Ioan Deaconu; Lucian Nicolae Tutelea

    2010-01-01

    This paper introduces a novel brushless, single winding and single stator, dual PM rotor axial-air-gap machine capable to deliver independently torque at the two rotors by adequate vector control. The proposed topologies, the circuit model, controlled dynamics simulation and preliminary 3D FEM torque production on a case study constitute the core of the paper. The proposed dual mechanical port system

  13. Variables that affect productivity in school foodservices.

    PubMed

    Mayo, C R; Olsen, M D; Frary, R B

    1984-02-01

    Productivity in school foodservice can be measured through the use of a statistical model designed to evaluate predictors of productivity. The model in this study utilized 6 productivity measures and 12 predictor variables which served to broaden the basis upon which school foodservice administrators can make sound decisions regarding productivity. Significant findings indicated that the number of employees producing meals should be kept to a minimum; contingencies inherent in each operating unit affect the total amount of labor time used to produce meals; managers should have at least a two-year certificate of training; menu steps should be kept to a minimum; the use of disposable ware may aid in keeping payroll cost at a controllable level. PMID:6693690

  14. Does Gracilis Tendon Harvest During ACL Reconstruction with a Hamstring Autograft Affect Torque of Muscles Responsible for Shin Rotation?

    PubMed

    Królikowska, Aleksandra; Czamara, Andrzej; Kentel, Maciej

    2015-01-01

    BACKGROUND A growing body of evidence indicates that in patients after anterior cruciate ligament reconstruction (ACLR) with a combined semitendinosus and gracilis (STGR) graft there are large deficits in the internal rotation strength, which has led some authors to recommend harvest of only ST tendon whenever possible. The purpose of this study was to assess the isometric (IT) and peak torque (PT) of the muscles responsible for shin rotation in patients after ACLR with an ST or with an STGR graft. MATERIAL AND METHODS Twenty patients with an ST graft and 20 patients with a combined STGR graft underwent a 6-month postoperative rehabilitation program after ACLR. At the end of the rehabilitation program, the IT and PT of the muscles responsible for internal (IR) and external rotation (ER) of the shin were measured. The results were compared to the results of a control group. Additionally, to determine the reliability of the dynamometer for clinical research, a test-retest assessment was performed. RESULTS There were no statistically significant differences between the 3 groups of participants. Nevertheless, in the STGR group there was a statistically significant difference between the IT of muscles internally rotating the shin in the involved knee and uninvolved knee at 25° of the internal shin rotation. CONCLUSIONS Comparison of IT and PT measurements performed after 24 weeks of postoperative rehabilitation generally showed no differences between patients after ACLR with the use of ST graft and patients who received a combination graft consisting of STGR. Nevertheless, there was an influence of GR harvest on internal shin rotation torque at a deep internal rotation angle. PMID:26190033

  15. Knee extension isometric torque production differences based on verbal motivation given to introverted and extroverted female children.

    PubMed

    McWhorter, J Wesley; Landers, Merrill; Young, Daniel; Puentedura, E Louie; Hickman, Robbin A; Brooksby, Candi; Liveratti, Marc; Taylor, Lisa

    2011-08-01

    To date, little research has been conducted to test the efficacy of different forms of motivation based on a female child's personality type. The purpose of this study was to evaluate the ability of female children to perform a maximal knee extension isometric torque test with varying forms of motivation, based on the child's personality type (introvert vs. extrovert). The subjects were asked to perform a maximal isometric knee extension test under three different conditions: 1) with no verbal motivation, 2) with verbal motivation from the evaluator only, and 3) with verbal motivation from a group of their peers and the evaluator combined. A 2×3 mixed ANOVA was significant for an interaction (F 2,62=17.530; p<0.0005). Post hoc testing for the introverted group showed that scores without verbal motivation were significantly higher than with verbal motivation from the evaluator or the evaluator plus the peers. The extroverted group revealed that scores with verbal motivation from the evaluator or the evaluator plus the peers were significantly higher than without verbal motivation. Results suggest that verbal motivation has a varying effect on isometric knee extension torque production in female children with different personality types. Extroverted girls perform better with motivation, whereas introverted girls perform better without motivation from others. PMID:20812856

  16. Evaluating how electronic charting affects resident productivity.

    PubMed

    Henning, Daniel; Horng, Steven; Sanchez, Leon

    2013-03-01

    Electronic medical records (EMRs) are becoming standard to improve the communication of information and longevity of patient records. Using an EMR in the emergency department (ED) could potentially slow residents evaluating patients. We evaluated how introducing an EMR affected resident productivity in an academic ED. We retrospectively studied first year emergency medicine residents from a large, academic, tertiary care center before-and-after the institution of an EMR on July 1st, 2010. No residents from the 2009-2010 class used the EMR, while all of the 2010-2011 residents used the EMR. We performed univariate and multivariate analyses using productivity, measured in patients per hour (pt/hr), as the primary outcome. A mixed-model multivariate regression, stratified by acuity zone, was created incorporating EMR and other possible confounders: admissions, signouts, daily ED volume, and days after July 1st for each shift. The study was granted IRB waiver of informed. We reviewed 2,405 shifts: 1,259 shifts before and 1,146 shifts after EMR implementation. When using the EMR, the univariate analysis estimated a 0.084 pt/hr increase in the high acuity zone (p = 0.1317) and 0.029 pt/hr decrease (p = 0.7085) in the low acuity zone. The multivariate regression estimated a 0.038 pt/hr increase (p = 0.3413) in the high acuity zone and a 0.009 pt/hr increase (p = 0.9049) in the low acuity zone with the EMR. Despite the expectation that electronic charting is detrimental to resident productivity, our analyses do not suggest a significant relationship between resident productivity and using the EMR. PMID:23334927

  17. Electric Field Driven Torque in ATP Synthase

    PubMed Central

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

    2013-01-01

    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

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

    PubMed Central

    Girard, Olivier; Racinais, Sébastien; Périard, Julien D

    2014-01-01

    Objectives To assess the time course of changes in rapid muscle force/torque production capacity and neuromuscular activity of lower limb muscles in response to prolonged (?2?h) match-play tennis under heat stress. Methods The rates of torque development (RTD) and electromyographic activity (EMG; ie, root mean square) rise were recorded from 0 to 30, –50, –100 and –200?ms during brief (3–5?s) explosive maximal isometric voluntary contractions (MVC) of the knee extensors (KE) and plantar flexors (PF), along with the peak RTD within the entirety of the torque-time curve. These values were recorded in 12 male tennis players before (prematch) and after (postmatch, 24 and 48?h) match-play in HOT (?37°C) and COOL (?22°C) conditions. Results The postmatch core temperature was greater in the HOT (?39.4°C) vs COOL (?38.7°C) condition (p<0.05). Reductions in KE RTD occurred within the 0–200?ms epoch after contraction onset postmatch and at 24?h, compared with prematch, independent of environmental conditions (p<0.05). A similar reduction in the KE peak RTD was also observed postmatch relative to prematch (p<0.05). No differences in KE RTD values were observed after normalisation to MVC torque. Furthermore, the rate of KE EMG activity rise remained unchanged. Conversely, the PF contractile RTD and rate of EMG activity rise were unaffected by the exercise or environmental conditions. Conclusions In the KE, a reduction in maximal torque production capacity following prolonged match-play tennis appears to account for the decrease in the rate of torque development, independent of environmental conditions, while remaining unchanged in the PF. PMID:24668381

  19. The production of a low-energy proton beam as a source of torque for a confined electron plasma

    Microsoft Academic Search

    Damon Todd

    2004-01-01

    A nonneutral plasma stored in a Penning-Malmberg trap takes the shape of a long cylinder of charge that rotates about the axial magnetic field of the confining solenoid. In the absence of external torques a plasma should survive indefinitely, but trap asymmetry and imperfect vacuum provide torques opposing the plasma's rotation which leads to plasma radial expansion and eventual loss.

  20. Hex ball torque test

    NASA Technical Reports Server (NTRS)

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

    1986-01-01

    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.

  1. Chapter 2 Climate Change Affecting Rice Production

    Microsoft Academic Search

    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

    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

  2. Reaction torque minimization techniques for articulated payloads

    NASA Technical Reports Server (NTRS)

    Kral, Kevin; Aleman, Roberto M.

    1988-01-01

    Articulated payloads on spacecraft, such as antenna telemetry systems and robotic elements, impart reaction torques back into the vehicle which can significantly affect the performance of other payloads. This paper discusses ways to minimize the reaction torques of articulated payloads through command-shaping algorithms and unique control implementations. The effects of reaction torques encountered on Landsat are presented and compared with simulated and measured data of prototype systems employing these improvements.

  3. Factors affecting microcin E492 production.

    PubMed

    de Lorenzo, V

    1985-03-01

    The production of the antibiotic polypeptide microcin E492 by Klebsiella pneumoniae RYC492 has been studied in respect to the composition of the culture medium. The nature of both the carbon and nitrogen sources had a dramatic effect on the levels of the microcin detected in the supernants of the liquid cultures. Gluconeogenic precursors such as lactate or citrate led to microcin titers 10 to 100 fold higher than those obtained with glucose. However, neither glycerol nor cAMP stimulated the production, ruling out a typical type of catabolic repression by glucose. Limitation of growth by phosphate or nitrogen led to a marked decrease in production. Treatment with mitomycin C did not result in an enhancement of microcin levels. PMID:3924870

  4. 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)

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

    1993-01-01

    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.

  5. Metabolic differences in temperamental Brahman cattle can affect productivity

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Many factors may adversely affect the growth and productivity of livestock. These include stressors associated with management practices, such as weaning, handling relative to transportation, and vaccination, that can modulate growth through the production of stress-related hormones (i.e., cortisol,...

  6. Dexel-based force-torque rendering and volume updating for 5DOF haptic product prototyping and virtual sculpting

    Microsoft Academic Search

    Weihang Zhu; Yuan-shin Lee

    2004-01-01

    This paper presents new techniques of Dexel-based force–torque rendering and volume-updating for haptic virtual sculpting of complex surfaces with a developed 5-DOF (degree of freedom) haptic interface. In the proposed methodology, 5-axis tool motion and analytical tool swept volume are formulated for updating the virtual stock material, which is represented with the Dexel volume model. Based on the tool motion

  7. Ultrasensitive polarimetric torque sensor

    Microsoft Academic Search

    Nicolas Javahiraly; Ayoub Chakari; Lionel Calegari; Patrick Meyrueis

    2002-01-01

    We propose the study and the design of an ultra sensitive polarimetric torque sensor. The principle is based on the measurement of the torsion angle (theta) induced on the shaft when a torque T is applied on it. This optical torque sensor has been tested for aluminum, steel and Plexiglas shafts with different geometries. The torsion angle has been measured

  8. Fine-tuning motor torque

    SciTech Connect

    O`Connor, L.

    1996-01-01

    Direct-torque control, a new method of regulating the output of ac induction motors, provides a swift response to input commands. A new variable-speed ac motor drive system that responds to torque input commands 10 times faster than current state-of-the-art drives has been developed by ABB Industrial Systems Inc. in New Berlin, Wis. The new control system, called the ACS 600, provides an alternative to drive systems that use sophisticated flux vector control or more routine pulse width modulation--the primary methods of regulating the output of ac induction motors. The ACS 600 is suitable for use in single motor applications that require a standard level of performance, such as conveyors, fans, and pumps. But it will likely be more valuable in applications that require the linking of multiple motors, such as textile production, and in applications that require tight control over torque, such as cranes, elevators, and centrifuges.

  9. Analysis of torque ripple due to phase commutation in brushless DC machines

    Microsoft Academic Search

    Renato Carlson; Michel Lajoie-Mazenc; J. C. d. S. Fagundes

    1992-01-01

    An original analytical study concerning the torque ripple due to phase commutation on brushless DC motors is developed. The results indicate that the relative ripple is independent of current, varies with speed, and may reach 50% of the average torque. The amplitude of the torque ripple and the duration of the commutation are analyzed, showing how this affects the torque-speed

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

    E-print Network

    Taranto, Michael Vincent

    1974-01-01

    PARAMETERS AFFECTING PRODUCTION AND CHARACTFR OF AN EXTRUSION TEXTURIZED PROTEIN PRODUCT FROM DEFATTED GLANDLESS COTTONSEED MEAL A Thesis by MICHAEL UINCENT TARANTO Submitted to the Graduate College of Texas A&M University in partial... fulfillment of the requirement for the degree of MASTER OF SCIENCE August 1974 Major Subject: Food Technology PARAMETERS AFFECTING PRODUCTION AND CHARACTER OF AN EXTRUSION TEXTURIZED PROTEIN PRODUCT FROM DEFATTFD GLANDLESS COTTONSEED MEAL A Thesis...

  11. MINI-REVIEW Bioprospecting for microbial products that affect

    E-print Network

    Christner, Brent C.

    , frozen food preparation, transgenic crops, and even weather modifica- tion. Ice-interacting proteins haveMINI-REVIEW Bioprospecting for microbial products that affect ice crystal formation and growth possibilities for a number of agricultural, biomedical, and industrial applications. Since their discov- ery

  12. UK TORQUE INTERCOMPARISON - 2007

    Microsoft Academic Search

    Andy Robinson; Andy Knott

    This paper gives details of a round robin torque comparison involving the National Physical Laboratory (NPL) and nine other UK laboratories. The comparison covered two ranges: 20 N·m to 100 N·m and 200 N·m to 1 kN·m. The work was an effective way of disseminating the unit of torque to industry via the UK's new national torque standard, giving assurance

  13. MET2 affects production of hydrogen sulfide during wine fermentation.

    PubMed

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

    2014-08-01

    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

  14. The torque correlation length and stochastic twist dynamics of DNA

    PubMed Central

    Banigan, Edward J.; Marko, John F.

    2014-01-01

    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. PMID:25019813

  15. Torque correlation length and stochastic twist dynamics of DNA

    NASA Astrophysics Data System (ADS)

    Banigan, Edward J.; Marko, John F.

    2014-06-01

    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.

  16. Angular Acceleration without Torque?

    ERIC Educational Resources Information Center

    Kaufman, Richard D.

    2012-01-01

    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.

  17. van der Waals torque

    NASA Astrophysics Data System (ADS)

    Esquivel-Sirvent, Raul; Schatz, George

    2014-03-01

    The theory of generalized van der Waals forces by Lifshtz when applied to optically anisotropic media predicts the existence of a torque. In this work we present a theoretical calculation of the van der Waals torque for two systems. First we consider two isotropic parallel plates where the anisotropy is induced using an external magnetic field. The anisotropy will in turn induce a torque. As a case study we consider III-IV semiconductors such as InSb that can support magneto plasmons. The calculations of the torque are done in the Voigt configuration, that occurs when the magnetic field is parallel to the surface of the slabs. The change in the dielectric function as the magnetic field increases has the effect of decreasing the van der Waals force and increasing the torque. Thus, the external magnetic field is used to tune both the force and torque. The second example we present is the use of the torque in the non retarded regime to align arrays of nano particle slabs. The torque is calculated within Barash and Ginzburg formalism in the nonretarded limit, and is quantified by the introduction of a Hamaker torque constant. Calculations are conducted between anisotropic slabs of materials including BaTiO3 and arrays of Ag nano particles. Depending on the shape and arrangement of the Ag nano particles the effective dielectric function of the array can be tuned as to make it more or less anisotropic. We show how this torque can be used in self assembly of arrays of nano particles. ref. R. Esquivel-Sirvent, G. C. Schatz, Phys. Chem C, 117, 5492 (2013). partial support from DGAPA-UNAM.

  18. Effect of stripe height on the critical current density of spin-torque noise in a tunneling magnetoresistive read head with a low resistance area product below 1.0 ? ?m2

    NASA Astrophysics Data System (ADS)

    Endo, Yasushi; Fan, Peng; Yamaguchi, Masahiro

    2015-05-01

    To understand the spin-torque effect on the noise in tunneling magnetoresistive (TMR) read heads, the GHz range noise spectra of TMR read heads with a narrow track width (w = 36 nm), and various stripe heights (h) are investigated as a function of the external magnetic field (Hex) and dc bias current density (j). The strong noise peak intensity depends on both Hex and j, indicating that the spin-torque affects the thermal mag-noise under a positive (negative) j for a positive (negative) Hex, regardless of h in the TMR heads. Due to the increased shape anisotropy, the critical current density (jc), where the non-thermal fluctuation noise originates from the spin-torque, increases markedly as the head dimension is reduced, and the maximum value of jc is approximately +1.5 × 1012 A/m2 for a head with w = 36 nm and h = 15 nm. These results demonstrate that the non-thermal fluctuation noise originating from the spin-torque in the TMR head can be suppressed in the current density range below 1012 A/m2, as the head dimension is reduced and the shape anisotropy is increased.

  19. Displaceable Gear Torque Controlled Driver

    NASA Technical Reports Server (NTRS)

    Cook, Joseph S., Jr. (Inventor)

    1997-01-01

    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.

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

    NASA Astrophysics Data System (ADS)

    Hissam, D. Andy

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

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

    PubMed

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

    2013-06-28

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

  2. Variable Torque Prescription: State of Art.

    PubMed Central

    Lacarbonara, Mariano; Accivile, Ettore; Abed, Maria R.; Dinoi, Maria Teresa; Monaco, Annalisa; Marzo, Giuseppe; Capogreco, Mario

    2015-01-01

    The variable prescription is widely described under the clinical aspect: the clinics is the result of the evolution of the state-of-the-art, aspect that is less considered in the daily literature. The state-of-the-art is the key to understand not only how we reach where we are but also to learn how to manage propely the torque, focusing on the technical and biomechanical purpos-es that led to the change of the torque values over time. The aim of this study is to update the clinicians on the aspects that affect the torque under the biomechanical sight, helping them to understand how to managing it, following the “timeline changes” in the different techniques so that the Variable Prescription Orthodontic (VPO) would be a suitable tool in every clinical case. PMID:25674173

  3. What Is Torque?

    NSDL National Science Digital Library

    Bartelt, Terry L. M.

    This interactive presentation, created by Terry Bartelt for the Electromechanical Digital Library, discusses the concept: "What is torque?" Bartelt begins with a simple example of torque, illustrated using a crank, pail, and water well. After this important introduction, the author introduces the student to the mathematics behind torque. Four different scenarios are used to help students walk through the calculations. Bartelt explains each using helpful interactive flash animations. These are not only useful in the explanation, but they allow the student to more fully engage with the topic. Overall, this is a nice introduction into both the physical and mathematical concept of force. The author concludes the presentation with a brief series of questions.

  4. Ironless armature torque motor

    NASA Technical Reports Server (NTRS)

    Fisher, R. L.

    1972-01-01

    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.

  5. Knowledge Elecitation for Factors Affecting Taskforce Productivity using a Questionnaire

    E-print Network

    Muhammad Sohail; Abdur Rashid Khan

    2009-07-30

    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.

  6. 29 CFR 784.138 - Perishable state of the aquatic product as affecting exemption.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ...APPLICABLE TO FISHING AND OPERATIONS ON AQUATIC PRODUCTS Exemptions Provisions Relating to Fishing and Aquatic Products General Character and Scope of the Section 13(a)(4) Exemption § 784.138 Perishable state of the aquatic product as affecting...

  7. 40 CFR 63.6004 - How do I demonstrate continuous compliance with the emission limits for tire production affected...

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ...compliance with the emission limits for tire production affected sources? 63.6004 Section...Continuous Compliance Requirements for Tire Production Affected Sources § 63.6004 How...compliance with the emission limits for tire production affected sources? (a) You...

  8. Emotions, affects and the production of social life.

    PubMed

    Fox, Nick J

    2015-06-01

    While many aspects of social life possess an emotional component, sociology needs to explore explicitly the part emotions play in producing the social world and human history. This paper turns away from individualistic and anthropocentric emphases upon the experience of feelings and emotions, attending instead to an exploration of flows of 'affect' (meaning simply a capacity to affect or be affected) between bodies, things, social institutions and abstractions. It establishes a materialist sociology of affects that acknowledges emotions as a part, but only a part, of a more generalized affective flow that produces bodies and the social world. From this perspective, emotions are not a peculiarly remarkable outcome of the confluence of biology and culture, but part of a continuum of affectivity that links human bodies to their physical and social environment. This enhances sociological understanding of the part emotions play in shaping actions and capacities in many settings of sociological concern. PMID:25788237

  9. Floating-Pinion Torque Splitter

    NASA Technical Reports Server (NTRS)

    Melles, Harold W.

    1994-01-01

    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.

  10. Multiple-Cantilever Torque Sensor

    NASA Technical Reports Server (NTRS)

    Lurie, Boris J.; Schier, J. Alan; Socha, Michael

    1989-01-01

    Sensitivity to spurious loads small. High stiffness, high resolution, and ease of fabrication among features of specially designed torque sensor. Device flexible and sensitive to torque about its cylindrical axis and stiff enough to be insensitive to bending about any perpendicular axis. Measures and transmits torque between driving and driven plates.

  11. An Approach to Sensorless Detection of Human Input Torque and Its Application to Power Assist Motion in Electric Wheelchair

    NASA Astrophysics Data System (ADS)

    Kaida, Yukiko; Murakami, Toshiyuki

    A wheelchair is an important apparatus of mobility for people with disability. Power-assist motion in an electric wheelchair is to expand the operator's field of activities. This paper describes force sensorless detection of human input torque. Reaction torque estimation observer calculates the total disturbance torque first. Then, the human input torque is extracted from the estimated disturbance. In power-assist motion, assist torque is synthesized according to the product of assist gain and the average torque of the right and left input torque. Finally, the proposed method is verified through the experiments of power-assist motion.

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

    Microsoft Academic Search

    Mohammad S. Islam; Sayeed Mir; Tomy Sebastian

    2004-01-01

    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

  13. Discourse Goals Affect the Process and Product of Nominal Metaphor Production.

    PubMed

    Utsumi, Akira; Sakamoto, Maki

    2014-06-13

    Although a large number of studies have addressed metaphor comprehension, only a few attempts have so far been made at exploring the process of metaphor production. Therefore, in this paper, we address the problem of how people generate nominal metaphors or identify an apt vehicle for a given topic of nominal metaphors. Specifically, we examine how the process and product of metaphor production differ between two discourse goals of metaphor, namely an explanatory purpose (e.g., to clarify) and a literary purpose (e.g., to aesthetically pleasing). Experiment 1 analyzed the metaphors (or vehicles) generated in the metaphor production task, and demonstrated that people identified more prototypical exemplars of the property to be attributed to the topic as a vehicle for explanatory metaphors than for literary metaphors. In addition, it was found that metaphors generated for the explanatory purpose were more apt and conventional, and had high topic-vehicle similarity than those generated for the literary purpose, while metaphors generated for the literary purpose were more familiar and imageable than those for the explanatory purpose. Experiment 2 used a priming paradigm to assess the online availability of prototypical and less prototypical members of the topic property during metaphor production. The result was that both prototypical and less prototypical members were activated in producing literary metaphors, while neither members were activated in the production of explanatory metaphors. These findings indicate that the process of metaphor production is affected by discourse goals of metaphor; less prototypical members of the category are searched for a vehicle during the production of literary metaphors, and thus literary metaphors are generated with less prototypical vehicles than explanatory metaphors. PMID:24924472

  14. Factors affecting strength and durability of densified biomass products

    Microsoft Academic Search

    Nalladurai Kaliyan; R. Vance Morey

    2009-01-01

    Effectiveness of a densification process to create strong and durable bonding in densified products such as pellets, briquettes, and cubes can be determined by testing the strength (i.e., compressive resistance, impact resistance, and water resistance), and durability (i.e., abrasion resistance) of the densified products. These tests can indicate the maximum force\\/stress that the densified products can withstand, and the amount

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

    PubMed Central

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

    2014-01-01

    The acute effect of whole-body vibration (WBV) training may enhance muscular performance via neural potentiation of the stretch reflex. The purpose of this study was to investigate if acute WBV exposure affects the stretch induced knee jerk reflex [onset latency and electromechanical delay (EMD)] and the isokinetic knee extensor peak torque performance. Twenty-two subjects were randomly assigned to the intervention or control group. The intervention group received WBV in a semi-squat position at 30° knee flexion with an amplitude of 0.69 mm, frequency of 45 Hz, and peak acceleration of 27.6 m/s2 for 3 minutes. The control group underwent the same semii-squatting position statically without exposure of WBV. Two-way mixed repeated measures analysis of variance revealed no significant group effects differences on reflex latency of rectus femoris (RF) and vastus lateralis (VL; p = 0.934 and 0.935, respectively) EMD of RF and VL (p = 0.474 and 0.551, respectively) and peak torque production (p = 0.483) measured before and after the WBV. The results of this study indicate that a single session of WBV exposure has no potentiation effect on the stretch induced reflex and peak torque performance in healthy young adults. Key Points There is no acute potentiation of stretch reflex right after whole body vibration. Acute whole body vibration does not improve mus-cle peak torque performance in healthy young adults. PMID:24570602

  16. Special-Purpose High-Torque Permanent-Magnet Motors

    NASA Technical Reports Server (NTRS)

    Doane, George B., III

    1995-01-01

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

  17. Chemical factors affecting fission product transport in severe LMFBR accidents

    SciTech Connect

    Wichner, R.P.; Jolley, R.L.; Gat, U.; Rodgers, B.R.

    1984-10-01

    This study was performed as a part of a larger evaluation effort on LMFBR accident, source-term estimation. Purpose was to provide basic chemical information regarding fission product, sodium coolant, and structural material interactions required to perform estimation of fission product transport under LMFBR accident conditions. Emphasis was placed on conditions within the reactor vessel; containment vessel conditions are discussed only briefly.

  18. Nanowire spin torque oscillator driven by spin orbit torques

    NASA Astrophysics Data System (ADS)

    Duan, Zheng; Smith, Andrew; Yang, Liu; Youngblood, Brian; Lindner, Jürgen; Demidov, Vladislav E.; Demokritov, Sergej O.; Krivorotov, Ilya N.

    2014-12-01

    Spin torque from spin current applied to a nanoscale region of a ferromagnet can act as negative magnetic damping and thereby excite self-oscillations of its magnetization. In contrast, spin torque uniformly applied to the magnetization of an extended ferromagnetic film does not generate self-oscillatory magnetic dynamics but leads to reduction of the saturation magnetization. Here we report studies of the effect of spin torque on a system of intermediate dimensionality—a ferromagnetic nanowire. We observe coherent self-oscillations of magnetization in a ferromagnetic nanowire serving as the active region of a spin torque oscillator driven by spin orbit torques. Our work demonstrates that magnetization self-oscillations can be excited in a one-dimensional magnetic system and that dimensions of the active region of spin torque oscillators can be extended beyond the nanometre length scale.

  19. Produce Surface Characteristics Affect Product Quality and Safety

    Technology Transfer Automated Retrieval System (TEKTRAN)

    The surface characteristics of fresh-cut fruits and vegetables vary largely among produce types, maturities and processing procedure. Studies have shown that the surface topography of produce significantly affected adherence, attachment, and biofilm formation of bacteria, as well as their removal a...

  20. Light and Temperature: Key Factors Affecting Walleye Abundance and Production

    Microsoft Academic Search

    Nigel P. Lester; Alan J. Dextrase; Robert S. Kushneriuk; Michael R. Rawson; Phil A. Ryan

    2004-01-01

    We used published information to determine optimum light and temperature conditions for walleye Sander vitreus (formerly Stizostedion vitreum) and then applied this simple niche definition to predict how water clarity, temperature, and bathymetry affect walleye habitat availability. Our model calculated thermal–optical habitat area (TOHA), the benthic area of a lake that supplies optimum light, and temperature conditions for walleye during

  1. Factors affecting the fermentative lactic acid production from renewable resources 1

    Microsoft Academic Search

    Karin Hofvendahl

    2000-01-01

    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.

  2. The Effect of Snake Muscular System on Actuators' Torque

    Microsoft Academic Search

    Seyed Mehdi Rezaei; Farshad Barazandeh; Mohammad S. Haidarzadeh; Seid M. Sadat

    2010-01-01

    Most of the research conducted on snake robots has been on movement, control or dynamics. There is only some research dealing\\u000a with the reduction of actuators’ sizes. Actuator size usually depends on the force\\/torque it can provide. Small actuators\\u000a imply a more efficient, long lasting, lighter and more flexible robot. The required force\\/torque and energy consumption consequently\\u000a is directly affected

  3. Factors affecting quality of fresh-cut horticultural products

    Microsoft Academic Search

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

    1996-01-01

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

  4. Factors affecting color stability of vinegar pickled meat products 

    E-print Network

    Ploch, Carol Ann

    1978-01-01

    . Smith Four replications of eight treatment combinations in model vinegar pickles were made (50 or 150 ppm sodium nitrite; 200 or 600 ppm sodium erythoxbate; 30 or 50 grain vinegar; 10 ppm FDIC Red No. 40 or Stange red shade). All pickles contained 7... 150 ppm nitrite and 600 ppm erythorbate. Visual color scores decreased (P& . 05) with increasing storage intervals. pH values were signifi- cantly (P &. 05) affected by color additive, vinegar strength, nitrite level, erythorbate level and storage...

  5. Processes affecting greenhouse gas production in experimental boreal reservoirs

    NASA Astrophysics Data System (ADS)

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

    2013-04-01

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

  6. Cultural practices in cotton (Gossypium hirsutum) affect weed seed production

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Billions of dollars are lost annually due to weeds or weed control, but weeds persist. Successful weed management systems must reduce weed populations. The objectives of this research were to 1) determine if cotton row spacing has an impact on weed growth and seed production and 2) evaluate the infl...

  7. Affected functional networks associated with sentence production in classic galactosemia.

    PubMed

    Timmers, Inge; van den Hurk, Job; Hofman, Paul Am; Zimmermann, Luc Ji; Uluda?, Kâmil; Jansma, Bernadette M; Rubio-Gozalbo, M Estela

    2015-08-01

    Patients with the inherited metabolic disorder classic galactosemia have language production impairments in several planning stages. Here, we assessed potential deviations in recruitment and connectivity across brain areas responsible for language production that may explain these deficits. We used functional magnetic resonance imaging (fMRI) to study neural activity and connectivity while participants carried out a language production task. This study included 13 adolescent patients and 13 age- and gender-matched healthy controls. Participants passively watched or actively described an animated visual scene using two conditions, varying in syntactic complexity (single words versus a sentence). Results showed that patients recruited additional and more extensive brain regions during sentence production. Both groups showed modulations with syntactic complexity in left inferior frontal gyrus (IFG), a region associated with syntactic planning, and in right insula. In addition, patients showed a modulation with syntax in left superior temporal gyrus (STG), whereas the controls did not. Further, patients showed increased activity in right STG and right supplementary motor area (SMA). The functional connectivity data showed similar patterns, with more extensive connectivity with frontal and motor regions, and restricted and weaker connectivity with superior temporal regions. Patients also showed higher baseline cerebral blood flow (CBF) in right IFG and trends towards higher CBF in bilateral STG, SMA and the insula. Taken together, the data demonstrate that language abnormalities in classic galactosemia are associated with specific changes within the language network. These changes point towards impairments related to both syntactic planning and speech motor planning in these patients. PMID:25979518

  8. How Soil Roughness Affects Runoff and Sediment Production?

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Effects of soil surface roughness on runoff and sediment production have not been clearly quantified, mostly due to the lack of a logical separation between geometric (i.e., surface microtopography) and process (i.e., runoff generation, soil detachment by raindrop and runoff) scales. In this resea...

  9. The FRIABLE1 Gene Product Affects Cell Adhesion in Arabidopsis

    PubMed Central

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

    2012-01-01

    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

  10. Repeated Torque Cycles Reduce Bolt Preload

    NASA Technical Reports Server (NTRS)

    Akian, Richard A.

    1993-01-01

    Report describes experiment to determine effect of repeated torque cycles upon preload applied by bolt tightened to given torque. Results indicate preload attainable at given torque decreases on subsequent cycles.

  11. How hollow melanosomes affect iridescent colour production in birds

    PubMed Central

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

    2013-01-01

    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

  12. Momentum Confinement at Low Torque

    SciTech Connect

    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

    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.

  13. Torque control for electric motors

    NASA Technical Reports Server (NTRS)

    Bernard, C. A.

    1980-01-01

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

  14. Cam-Design Torque Wrench

    NASA Technical Reports Server (NTRS)

    Schick, P. H. J.; Gattuso, S. A.

    1982-01-01

    New Torque wrench for electrical connnectors automatically tightens its grip with increasing torque to insure against slippage. Tool requires only minimal clearance between connector and adjacent structures or components. Wrench is operated with one hand and can be used on connectors of various shapes.

  15. Fault-Tolerant Torque Control of BLDC Motors

    Microsoft Academic Search

    Farhad Aghili

    2011-01-01

    Fault tolerance is critical for servomotors used in high-risk applications, such as aerospace, robots, and military. These motors should be capable of continued functional operation, even if insulation failure or open-circuit of a winding occur. This paper presents a fault-tolerant (FT) torque controller for brushless dc (BLdc) motors that can maintain accurate torque production with minimum power dissipation, even if

  16. Nanowire Spin Torque Oscillator Driven by Spin Orbit Torques

    NASA Astrophysics Data System (ADS)

    Smith, Andrew; Duan, Zheng; Yang, Liu; Youngblood, Brian; Krivorotov, Ilya

    2014-03-01

    We report microwave signal emission from a spin torque oscillator driven by spin orbit torques in a 17 um long Py(5 nm)/Pt(5 nm) ferromagnetic nanowire with an 1.8 um long active region. The emitted signal arises from excitation of the bulk and edge spin wave eigenmodes of the nanowire and detected with anisotropic magnetoresistance. This type of self-oscillatory dynamics is qualitatively different from the previously reported self-localized nonlinear bullet mode excited by spin orbit torques in extended ferromagnetic films. The eigenmode self-oscillations in the nanowire geometry are enabled by geometric confinement suppressing nonlinear magnon scattering. Our work demonstrates feasibility of spin torque oscillators with a micrometer-scale active region.

  17. Thermomagnetic Torque in Nh3 

    E-print Network

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

    1970-01-01

    there is no torque. Also, there is no torque in He which has a magnetic moment. This thermomag- netic torque (Scott effect) is related to the Senftle- ben-Beenakker (SB) effect which causes a change of viscosity and thermal conductivity with magnetic field.... Extensive theoretical work has been carried out on the SB effect, and a large amount of theoretical work has been done on the Scott effect. Levi and Beenakker, ' using solutions of the Boltzmann equation based on the third Chapman- Enskog approximation...

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

    E-print Network

    Arhonditsis, George B.

    by-products have been reported to result from the use of chlorine for drinking water disinfection classification and qualitative target levels set by the WHO and the European Union for chlorination byFACTORS AFFECTING THE FORMATION OF ORGANIC BY-PRODUCTS DURING WATER CHLORINATION: A BENCH

  19. RICE PRODUCTION SYSTEM AND STUDY METHODOLOGY AFFECT RICE IRRIGATION-WATER USE ESTIMATES

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Rice irrigation-water use was estimated in Mississippi (MS) and Arkansas (AR) in 2003 and 2004. Irrigation inputs were compared on naturally sloping and precision-graded fields. In MS, rice production consumed, on average, 895 mm water, but irrigation inputs were greatly affected by production syste...

  20. Torque generated by the bacterial flagellar motor close to stall.

    PubMed Central

    Berry, R M; Berg, H C

    1996-01-01

    In earlier work in which electrorotation was used to apply external torque to tethered cells of the bacterium Escherichia coli, it was found that the torque required to force flagellar motors backward was considerably larger than the torque required to stop them. That is, there appeared to be substantial barrier to backward rotation. Here, we show that in most, possibly all, cases this barrier is an artifact due to angular variation of the torque applied by electrorotation, of the motor torque, or both; the motor torque appears to be independent to speed or to vary linearly with speed up to speeds of tens of Hertz, in either direction. However, motors often break catastrophically when driven backward, so backward rotation is not equivalent to forward rotation. Also, cells can rotate backward while stalled, either in randomly timed jumps of 180 degrees or very slowly and smoothly. When cells rotate slowly and smoothly backward, the motor takes several seconds to recover after electrorotation is stopped, suggesting that some form of reversible damage has occurred. These findings do not affect the interpretation of electrorotation experiments in which motors are driven rapidly forward. PMID:8968619

  1. Torque generated by the bacterial flagellar motor close to stall.

    PubMed

    Berry, R M; Berg, H C

    1996-12-01

    In earlier work in which electrorotation was used to apply external torque to tethered cells of the bacterium Escherichia coli, it was found that the torque required to force flagellar motors backward was considerably larger than the torque required to stop them. That is, there appeared to be substantial barrier to backward rotation. Here, we show that in most, possibly all, cases this barrier is an artifact due to angular variation of the torque applied by electrorotation, of the motor torque, or both; the motor torque appears to be independent to speed or to vary linearly with speed up to speeds of tens of Hertz, in either direction. However, motors often break catastrophically when driven backward, so backward rotation is not equivalent to forward rotation. Also, cells can rotate backward while stalled, either in randomly timed jumps of 180 degrees or very slowly and smoothly. When cells rotate slowly and smoothly backward, the motor takes several seconds to recover after electrorotation is stopped, suggesting that some form of reversible damage has occurred. These findings do not affect the interpretation of electrorotation experiments in which motors are driven rapidly forward. PMID:8968619

  2. Heat Control via Torque Control in Friction Stir Welding

    NASA Technical Reports Server (NTRS)

    Venable, Richard; Colligan, Kevin; Knapp, Alan

    2004-01-01

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

  3. Rotating vector methods for smooth torque control of a switched reluctance motor drive

    SciTech Connect

    Nagel, N.J.; Lorenz, R.D.

    2000-04-01

    This paper has two primary contributions to switched reluctance motor (SRM) control: a systematic approach to smooth torque production and a high-performance technique for sensorless motion control. The systematic approach to smooth torque production is based on development of novel rotating spatial vectors methods that can be used to predict the torque produced in an arbitrary SRM. This analysis directly leads to explicit, insightful methods to provide smooth torque control of SRM's. The high-performance technique for sensorless motion control is based on a rotating vector method for high bandwidth, high resolution, position, and velocity estimation suitable for both precise torque and motion control. The sensorless control and smooth torque control methods are both verified experimentally.

  4. Torque Tube Stiffens Trailer Frame

    NASA Technical Reports Server (NTRS)

    Macmartin, Malcolm J.

    1992-01-01

    Trailer frame incorporates longitudinal torque tube absorbing torsional loads and stiffening trailer. Used to transport large cylindrical objects like pressure vessels, tanks, and rocket engines without subjecting them to damage or excessive loads.

  5. Pressurized fluid torque driver control and method

    NASA Technical Reports Server (NTRS)

    Cook, Joseph S., Jr. (inventor)

    1994-01-01

    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.

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

    SciTech Connect

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

    2008-04-01

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

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

    PubMed

    Shen, Z H; Seipel, J E

    2012-12-01

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

  8. Tapered nanowire spin torque oscillator driven by spin orbit torques

    NASA Astrophysics Data System (ADS)

    Yang, Liu; Smith, Andrew; Youngblood, Brian; Duan, Zheng; Krivorotov, Ilya

    2015-03-01

    We report microwave signal emission from a spin torque oscillator driven by spin orbit torques in a tapered Pt(7nm)/Py(5nm) ferromagnetic nanowire with 2 um long active region. The tapered nanowire oscillator exhibits lower spectral linewidth (<1 MHz) and higher integrated power (>1 nW) compared to a spin torque oscillator based on a nanowire with spatially uniform width. The tapered nanowire oscillator has two distinct regimes of the microwave signal emission: a low-current, low-amplitude regime with a soft onset of the microwave emission and a higher-current regime with a hard onset of large-amplitude oscillations. The existence of the two regimes arises from spatially non-uniform effective damping in the tapered nanowire geometry. The non-uniformity of the effective damping results in nucleation of magnetization self-oscillations at the narrow end of the nanowire and subsequent steady growth of the self-oscillatory region with increasing current throughout the low-power regime. The sudden turn on of the high-power regime takes place at a critical current, for which spatially averaged effective damping of the nanowire changes sign from positive to negative. Our work paves the way towards high-power spectrally pure spin torque oscillators driven by spin orbit torques.

  9. A nuclear mutation affects the synthesis of the chloroplast psbA gene production Chlamydomonas reinhardtii

    Microsoft Academic Search

    Jacqueline Girard-Bascou; Yves Pierre; Dominique Drapier

    1992-01-01

    The effect of the nuclear mutation F34 on the synthesis of chloroplast-encoded photosystem II (PSII) polypeptides has been controversal. While we had concluded that the synthesis of the psbC gene product (P6) was specifically deficient in this mutant, another laboratory has found that the synthesis of the psbA gene product, the herbicide-binding protein D1, was primarily affected. These conflicting results

  10. Split torque transmission load sharing

    NASA Technical Reports Server (NTRS)

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

    1992-01-01

    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.

  11. 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

    2010-07-01

    ... true Minimum Data for Continuous...Limits for Tire Production Affected Sources...Part 63—Minimum Data for Continuous...Limits for Tire Production Affected Sources...maintain minimum data to show continuous...limits for tire production affected...

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

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Glycerol is a major byproduct from biodiesel production, and developing new uses for glycerol is imperative to overall economics and sustainability of the biodiesel industry. With the aim of producing xylitol and/or arabitol as the value-added products from glycerol, 214 yeast strains, many osmotole...

  13. Factors that Affect Student Motivation in a Dairy Products Elective Course

    ERIC Educational Resources Information Center

    Ismail, Baraem; Hayes, Kirby

    2005-01-01

    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…

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

    ERIC Educational Resources Information Center

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

    2011-01-01

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

  15. Factors Affecting the Functional Properties of Whey Protein Products: A Review

    Microsoft Academic Search

    M. H. Abd El-Salam; Safinaz El-Shibiny; Aida Salem

    2009-01-01

    Numerous why protein products (WPP) have been developed as excellent food ingredients with unique functional properties. However, the functional properties of WPP are affected by several compositional and processing factors. Recently, novel processing technologies such as high hydrostatic pressure, ultrasound, extrusion and tribomechanical activation have been used to modify the functional properties of WPP. Also, WPP have been used as

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

    E-print Network

    van Kessel, Chris

    to poor germination, poor seedling growth or insufficient seedlings. Rice needs to be sown at times whereOpportunities to increasing dry season rice productivity in low temperature affected areas of Queensland, Brisbane, Queensland 4072, Australia c Department of Plant and Environmental Sciences, University

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

    Microsoft Academic Search

    T. A. Jones; D. C. Nielson

    1994-01-01

    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

  18. ALOX5 gene variants affect eicosanoid production and response to fish oil supplementation

    Technology Transfer Automated Retrieval System (TEKTRAN)

    The objective of this study was to determine whether 5-lipoxygenase (ALOX5) gene variants associated with cardiovascular disease affect eicosanoid production by monocytes. The study was a randomized, double-masked, parallel intervention trial with fish oil (5.0 g of fish oil daily, containing 2.0 g ...

  19. Research on torque balance of permanent-magnet brushless DC motor

    Microsoft Academic Search

    Haifeng Wang; Jie Yang; Guobiao Gu

    2007-01-01

    We would encounter the output torque balance problem of several motors during many industry productive processes such as steel rolling, papermaking, printing, electric vehicle, ship propelling and so on in modern times. However the normal speed control method can't meet with the requirements of the multi-motors output torque balance for that the load of different motor may not be equal

  20. Maximum torque control of an induction machine in the field weakening region

    Microsoft Academic Search

    Sang-Hoon Kim; Seung-Ki Sul

    1995-01-01

    In this paper, a new approach to the induction machine control that ensures the production of maximum torque per ampere over the entire field weakening region is presented. Considering the limitations of voltage and current, the optimal current condition for yielding the maximum torque is obtained. Also, since the onset of the field weakening operation is automatically adjusted according to

  1. Power Tool Would Require Little Bracing Torque

    NASA Technical Reports Server (NTRS)

    Canniff, Joseph H.

    1995-01-01

    Proposed rotary power tool exerts required torque on workpiece, but little or no bracing torque applied to tool to keep it from turning in opposite direction. Instead, working torque neutralized by nearly equal and opposite torque generated within tool. Used easily underwater, on slippery surfaces, or in other environments in which external bracing of tool against rotation difficult or impossible. Minimizes armbreaking forces resulting from tool binding.

  2. Periodic torque ripples minimization in PMSM using learning variable structure control based on a torque observer

    Microsoft Academic Search

    Weizhe Qian; J. X. Xu; S. K. Panda

    2003-01-01

    PM synchronous motor drives are widely used for high-performance industrial servo applications where torque smoothness is an essential requirement. However, parasitic torque pulsations do exist in PMSM drive due to non-perfect sinusoidal flux distribution, cogging torque and current measurement errors. A consequence of these torque ripples is speed oscillation that deteriorates the drive performance particularly at low speeds. In this

  3. Electromagnetic Torque Tweezers: A Versatile Approach for Measurement of Single-Molecule Twist and Torque

    E-print Network

    Dekker, Nynke

    Electromagnetic Torque Tweezers: A Versatile Approach for Measurement of Single-Molecule Twist of freedom. Here we present electromagnetic torque tweezers (eMTT) that combine permanent and electromagnets from single-molecules to living cells. KEYWORDS: Electromagnetic torque tweezers, torque spectroscopy

  4. Quenched Slonczewski windmill in spin-torque vortex oscillators

    NASA Astrophysics Data System (ADS)

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

    2012-12-01

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

  5. Redundancy resolution of manipulators through torque optimization

    Microsoft Academic Search

    John M. Hollerbach; Ki C. Suh

    1985-01-01

    Methods for resolving kinematic redundancies of manipulators by the effect on joint torque are examined. When the generalized inverse is formulated in terms of accelerations and incorporated into the dynamics, the effect of redundancy resolution on joint torque can be directly reflected. One method chooses the joint acceleration null-space vector to minimize joint torque in a least squares sense; when

  6. Viral protease inhibitors affect the production of virulence factors in Cryptococcus neoformans.

    PubMed

    Sidrim, J J C; Perdigão-Neto, L V; Cordeiro, R A; Brilhante, R S N; Leite, J J G; Teixeira, C E C; Monteiro, A J; Freitas, R M F; Ribeiro, J F; Mesquita, J R L; Gonçalves, M V F; Rocha, M F G

    2012-07-01

    The effects of the protease inhibitors saquinavir, darunavir, ritonavir, and indinavir on growth inhibition, protease and phospholipase activities, as well as capsule thickness of Cryptococcus neoformans were investigated. Viral protease inhibitors did not reduce fungal growth when tested in concentrations ranging from 0.001 to 1.000 mg/L. A tendency toward increasing phospholipase activity was observed with the highest tested drug concentration in a strain-specific pattern. However, these drugs reduced protease activity as well as capsule production. Our results confirm a previous finding that antiretroviral drugs affect the production of important virulence factors of C. neoformans. PMID:22716223

  7. FACTORS AFFECTING THE ADOPTION OF VALUE-ADDED PRODUCTION ON COW-CALF FARMS

    Microsoft Academic Search

    Michael P. Popp; Merle D. Faminow; Lucas D. Parsch

    1999-01-01

    Factors that affect the decision to feed or sell calves at weaning are analyzed for Arkansas cow-calf operators. A discrete choice logit model is used to analyze the adoption of value-added cattle production. Farm size, human capital, perception of risk\\/returns and enterprise diversification are hypothesized to explain this decision. Regional factors and land quality are also accounted for. Operator perceptions

  8. Direct torque control of permanent magnet drives

    SciTech Connect

    French, C.; Acarnley, P. [Univ. of Newcastle upon Tyne (United Kingdom)

    1995-12-31

    Many permanent magnet motor drives use an open loop form of torque control, based on the assumption that output torque is proportional to applied current. In a practical motor this assumption may not always be correct, due to sub-optimal alignment of magnets, non-uniformity of magnetic material, current sensor non-linearities and current controller limitations. These factors, together with non-optimized current references, can lead to high values of torque ripple and copper loss. This paper describes a method of estimating the electro-magnetic torque from the rate of change of co-energy with respect to position, thus taking account of mutual torque, reluctance torque and saturation effects. The paper shows how the estimator can be used in a direct torque control scheme. The direct torque controller maximizes the torque:copper loss ratio. Implementation of the direct torque controller in a DSP based drive system is described, with steady-state and transient experimental results illustrating the effectiveness of the direct torque control scheme.

  9. A Study on Reduction of Vibration Based on Decreased Cogging Torque for Interior Type Permanent Magnet Motor

    Microsoft Academic Search

    Seung-Hoon Lee; Kwang-Kyu Han; Ho-Jin Ahn; Gyu-Hong Kang; Young-Dae Son; Gyu-Tak Kim

    2008-01-01

    This paper presents a reduction method of vibration based on decreased cogging torque for interior type permanent magnet motor. The vibration source which affects biggest in the vibration of the interior type permanent magnet motor is the force, cogging torque, of the radius direction in compliance with a magnetic energy from between stator and the rotor. The notch is established

  10. Proximity to forest edge does not affect crop production despite pollen limitation.

    PubMed

    Chacoff, Natacha P; Aizen, Marcelo A; Aschero, Valeria

    2008-04-22

    A decline in pollination function has been linked to agriculture expansion and intensification. In northwest Argentina, pollinator visits to grapefruit, a self-compatible but pollinator-dependent crop, decline by approximately 50% at 1km from forest edges. We evaluated whether this decrease in visitation also reduces the pollination service in this crop. We analysed the quantity and quality of pollen deposited on stigmas, and associated limitation of fruit production at increasing distances (edge: 10, 100, 500 and 1000m) from the remnants of Yungas forest. We also examined the quantitative and qualitative efficiency of honeybees as pollen vectors. Pollen receipt and pollen tubes in styles decreased with increasing distance from forest edge; however, this decline did not affect fruit production. Supplementation of natural pollen with self- and cross-pollen revealed that both pollen quantity and quality limited fruit production. Despite pollen limitation, honeybees cannot raise fruit production because they often do not deposit sufficient high-quality pollen per visit to elicit fruit development. However, declines in visitation frequency well below seven visits during a flower's lifespan could decrease production beyond current yields. In this context, the preservation of forest remnants, which act as pollinator sources, could contribute to resilience in crop production. Like wild plants, pollen limitation of the yield among animal-pollinated crops may be common and indicative not only of pollinator scarcity, but also of poor pollination quality, whereby pollinator efficiency, rather than just abundance, can play a broader role than previously appreciated. PMID:18230596

  11. Observations of nitric acid removal that strongly affects the relationship between ozone and NOx oxidation products

    NASA Astrophysics Data System (ADS)

    Neuman, J.; Nowak, J. B.; Zheng, W.; Flocke, F.; Ryerson, T.; Trainer, M.; Holloway, J.; Parrish, D.; Fehsenfeld, F.

    2007-12-01

    Over the past 20 years, the relationship between ozone formation and NOx precursors has been examined in order to understand the factors that control ozone pollution. Understanding the fate of NOx and its oxidation products is necessary to accurately determine the dependence of ozone upon NOx. Measurements of ozone, NOx, and NOx oxidation products were obtained from the NOAA WP-3 aircraft during the 2006 Texas Air Quality Study under a variety of meteorological conditions in plumes downwind from Houston, Texas. Over 50 crosswind transects of coalesced plumes from the Houston urban and industrial areas were examined. Nitric acid, which is one of the primary NOx oxidation products, can be removed rapidly from the atmosphere by deposition. This deposition affects reactive nitrogen partitioning and causes an increase in the slope of the correlation between ozone and the products of NOx oxidation (often interpreted as ozone production efficiency). During this study, nitric acid loss increased when wind speeds were high, causing the ozone to NOy-NOx correlation slopes to increase dramatically. Accounting for this loss is necessary to use correlation slopes of ozone versus NOy-NOx to represent an ozone production efficiency that describes the NOx-VOC chemistry.

  12. Reconstructing the intermittent dynamics of the torque in wind turbines

    NASA Astrophysics Data System (ADS)

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

    2014-06-01

    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.

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

    NASA Astrophysics Data System (ADS)

    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

    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.

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

    NASA Astrophysics Data System (ADS)

    Alday, Josu; Resco de Dios, Víctor

    2014-05-01

    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.

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

    PubMed Central

    2014-01-01

    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

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

    Microsoft Academic Search

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

    2010-01-01

    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

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

    E-print Network

    Clegg, Chally Joel

    1991-01-01

    the Process and Cooked Product. (August 1991) Chally Joel Clegg, B. S. , University of Nebraska-Lincoln Chair of Advisory Committee: Dr. Lloyd Rooney Pearl millet Pennisetum american m) was parboiled by boil-soak-boil (BSB), soak-boil (SB), or soak... not significantly affect the level of broken kernels compared to nonparboiled pearl millet. BSB, SB, and SBS methods dried slowly were similar in milling properties. Otherwise, rapid drying of BSB method milled best, followed by SB, then SBS method. Sun and oven...

  18. PREFACE: The Science of Making Torque from Wind 2014 (TORQUE 2014)

    NASA Astrophysics Data System (ADS)

    Mann, Jakob; Bak, Christian; Bechmann, Andreas; Bingöl, Ferhat; Dellwik, Ebba; Dimitrov, Nikolay; Giebel, Gregor; Hansen, Martin O. L.; Jensen, Dorte Juul; Larsen, Gunner; Aagaard Madsen, Helge; Natarajan, Anand; Rathmann, Ole; Sathe, Ameya; Nørkær Sørensen, Jens; Nørkær Sørensen, Niels

    2014-06-01

    The 186 papers in this volume constitute the proceedings of the fifth Science of Making Torque from Wind conference, which is organized by the European Academy of Wind Energy (EAWE, www.eawe.eu). The conference, also called Torque 2014, is held at the Technical University of Denmark (DTU) 17-20 June 2014. The EAWE conference series started in 2004 in Delft, the Netherlands. In 2007 it was held in Copenhagen, in 2010 in Heraklion, Greece, and then in 2012 in Oldenburg, Germany. The global yearly production of electrical energy by wind turbines has grown approximately by 25% annually over the last couple of decades and covers now 2-3% of the global electrical power consumption. In order to make a significant impact on one of the large challenges of our time, namely global warming, the growth has to continue for a decade or two yet. This in turn requires research and education in wind turbine aerodynamics and wind resources, the two topics which are the main subjects of this conference. Similar to the growth in electrical power production by wind is the growth in scientific papers about wind energy. Over the last decade the number of papers has also grown by about 25% annually, and many research based companies all over the world are founded. Hence, the wind energy research community is rapidly expanding and the Torque conference series offers a good opportunity to meet and exchange ideas. We hope that the Torque 2014 will heighten the quality of the wind energy research, while the participants will enjoy each others company in Copenhagen. Many people have been involved in producing the Torque 2014 proceedings. The work by more than two hundred reviewers ensuring the quality of the papers is greatly appreciated. The timely evaluation and coordination of the reviews would not have been possible without the work of sixteen ''section editors'' all from DTU Wind Energy: Christian Bak, Andreas Bechmann, Ferhat Bingöl, Ebba Dellwik, Nikolay Dimitrov, Gregor Giebel, Martin O L Hansen, Dorte Juul Jensen, Gunner Larsen, Helge Aagaard Madsen, Jakob Mann, Anand Natarajan, Ole Rathmann, Ameya Sathe, Jens Nørkær Sørensen and Niels Nørkær Sørensen, who are all co-editors of these proceedings. The resources provided by the Center for Computational Wind Turbine Aerodynamics and Atmospheric Turbulence funded by the Danish Council for Strategic Research grant no. 09-067216 and the Danish Ministry of Science, Innovation and Higher Education Technology and Production, grant no. 11- 117018 are gratefully acknowledged. We are also immensely indebted to the very responsive help and support from the editorial team at IoP, especially Sarah Toms and Anete Ashton, during the reviewing process of these proceedings. We are looking forward to meeting you in Copenhagen and also to Torque 2016, which will take place at the Technical University of Munich, Germany. Roskilde, Denmark, June 2014 Ebba Dellwik, Ameya Sathe and Jakob Mann Technical University of Denmark EAWE DTU

  19. Magnetic field control. [electromechanical torquing device

    NASA Technical Reports Server (NTRS)

    Haeussermann, W. (inventor)

    1982-01-01

    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.

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

    NASA Astrophysics Data System (ADS)

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

    2008-12-01

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

  1. Long-term productivity of lowland and upland switchgrass cytotypes as affected by cutting frequency.

    PubMed

    Monti, A; Bezzi, G; Pritoni, G; Venturi, G

    2008-11-01

    A considerable number of studies has been conducted on switchgrass (Panicum virgatum L.) as a bioresource for energy over the last few years. Nonetheless, some important issues concerning the agro-technique are still open. This research examines the long-term total dry matter yield (TDM) and ash content of two lowland (L) and two upland (U) switchgrass cytotypes, as affected by one or two-cut system, under southern EU climatic conditions (44 degrees 33' N). Overall, L produced higher TDM than U (on average 14.9 and 11.7 Mg ha(-1), respectively); two-cut system allowed to produce higher biomass yields (especially in U) than single harvest during the two first years, but it also drastically reduced plant vigour and productivity of all cytotypes in the following two years. Moreover, under two-cut system almost total seasonal biomass derived from the early harvest, while the second cut slightly contributed to the total seasonal biomass, nor it appeared to offset the additional harvest costs. Biomass quality was also significantly affected by cutting frequency, with two-cut system leading to a considerably higher ash content of biomass. Therefore, it is perceived that two-cut system is not worthwhile with U and L cytotypes as bioresource for energy production under southern EU conditions. PMID:18387801

  2. TITER AND PRODUCT AFFECTS THE DISTRIBUTION OF GENE EXPRESSION AFTER INTRAPUTAMINAL CONVECTION-ENHANCED DELIVERY

    PubMed Central

    Emborg, Marina E.; Hurley, Samuel A.; Joers, Valerie; Tromp, Do P.M.; Swanson, Christine R.; Ohshima-Hosoyama, Sachiko; Bondarenko, Viktorya; Cummisford, Kyle; Sonnemans, Marc; Hermening, Stephan; Blits, Bas; Alexander, Andrew L.

    2014-01-01

    Background Efficacy and safety of intracerebral gene therapy for brain disorders, like Parkinson’s disease, depends on appropriate distribution of gene expression. Objectives To assess if the distribution of gene expression is affected by vector titer and protein type. Methods Four adult macaque monkeys seronegative for adeno-associated virus 5 (AAV5) received in the right and left ventral postcommisural putamen 30?l inoculation of a high or low titer suspension of AAV5 encoding glial derived neurotrophic factor (GDNF) or green fluorescent protein (GFP). Inoculations were performed using convection enhanced delivery and intraoperative MRI (IMRI). Results IMRI confirmed targeting and infusion cloud irradiating from the catheter tip into surrounding area. Postmortem analysis six weeks after surgery revealed GFP and GDNF expression ipsilateral to the injection side that had a titer-dependent distribution. GFP and GDNF expression was also observed in fibers in the Substantia Nigra (SN) pars reticulata (pr), demonstrating anterograde transport. Few GFP-positive neurons were present in the SN pars compacta (pc), possibly by direct retrograde transport of the vector. GDNF was present in many SNpc and SNpr neurons. Conclusions After controlling for target and infusate volume, intracerebral distribution of gene product is affected by vector titer and product biology. PMID:24943657

  3. Optimal design and selection of magneto-rheological brake types based on braking torque and mass

    NASA Astrophysics Data System (ADS)

    Nguyen, Q. H.; Lang, V. T.; Choi, S. B.

    2015-06-01

    In developing magnetorheological brakes (MRBs), it is well known that the braking torque and the mass of the MRBs are important factors that should be considered in the product’s design. This research focuses on the optimal design of different types of MRBs, from which we identify an optimal selection of MRB types, considering braking torque and mass. In the optimization, common types of MRBs such as disc-type, drum-type, hybrid-type, and T-shape types are considered. The optimization problem is to find an optimal MRB structure that can produce the required braking torque while minimizing its mass. After a brief description of the configuration of the MRBs, the MRBs’ braking torque is derived based on the Herschel-Bulkley rheological model of the magnetorheological fluid. Then, the optimal designs of the MRBs are analyzed. The optimization objective is to minimize the mass of the brake while the braking torque is constrained to be greater than a required value. In addition, the power consumption of the MRBs is also considered as a reference parameter in the optimization. A finite element analysis integrated with an optimization tool is used to obtain optimal solutions for the MRBs. Optimal solutions of MRBs with different required braking torque values are obtained based on the proposed optimization procedure. From the results, we discuss the optimal selection of MRB types, considering braking torque and mass.

  4. Effects of flux and torque hysteresis band amplitude in direct torque control of induction machines

    Microsoft Academic Search

    D. Casadei; G. Grandi; G. Serra; A. Tani

    1994-01-01

    Direct torque control of induction machines allows high dynamic performance to be obtained utilising a simple signal processing method. Furthermore, this control technique does not require current regulators so reducing the hardware requirements. In this paper, the influence of the amplitude of flux and torque hysteresis bands on switching frequency, torque and flux ripple, current distortion and drive losses is

  5. 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

    2013-07-01

    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 . . ....

  6. 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

    2012-07-01

    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 . . ....

  7. 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

    2010-07-01

    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 . . ....

  8. 40 CFR Table 10 to Subpart Xxxx of... - Continuous Compliance With the Emission Limits for Tire Production Affected Sources

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    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 . . ....

  9. 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

    2011-07-01

    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 . . ....

  10. Bax Affects Production of Reactive Oxygen by the Mitochondria of Non-apoptotic Neurons

    PubMed Central

    Kirkland, Rebecca A.; Franklin, James L.

    2007-01-01

    Depriving sympathetic neurons in cell culture of nerve growth factor (NGF) causes their apoptotic death. Bax-induced release of cytochrome c from mitochondria and the subsequent activation of cytosolic caspases are central to this death. A Bax-dependent increase of mitochondrial-derived reactive oxygen species (ROS) that is an important component of the apoptotic cascade in these cells begins soon after NGF withdrawal. Here we report that Bax can also influence mitochondrial production of ROS in non-apoptotic sympathetic neurons. We determined ROS levels by using confocal microscopy to monitor changes in the fluorescence intensity of a redox-sensitive dye loaded into single cells. ROS levels were similar in NGF-replete bax wild-type neurons and neurons from which bax had been deleted. To enhance any effects that Bax might have on ROS levels in NGF-replete cells we exposed cultures to the ATP synthase inhibitor, oligomycin. This treatment hyperpolarizes mitochondrial membrane potential (??m), an event that can favor increased ROS production. NGF-replete neurons from mice in which bax had been deleted had much higher levels of mitochondrial-derived ROS when treated with oligomycin than did bax wild-type cells. Oligomycin treatment also caused greater hyperpolarization of ??m in bax-deleted cells than in wild-type cells. These findings indicate that Bax can affect mitochondrial ROS production in non-apoptotic neurons and may do so by altering ??m. PMID:17097638

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

    NASA Technical Reports Server (NTRS)

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

    2001-01-01

    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.

  12. Magnetic Tweezers for the Measurement of Twist and Torque

    E-print Network

    Dekker, Nynke

    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

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

    SciTech Connect

    Taniguchi, Tomohiro; Tsunegi, Sumito; Kubota, Hitoshi; Imamura, Hiroshi [National Institute of Advanced Industrial Science and Technology (AIST), Spintronics Research Center, Tsukuba 305-8568 (Japan)

    2014-04-14

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

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

    NASA Technical Reports Server (NTRS)

    Roithmayr, Carlos M.

    1999-01-01

    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.

  15. Modeling mechanical torque in wind turbines

    Microsoft Academic Search

    J. Villanueva; L. Alvarez-Icaza

    2009-01-01

    The mechanical torque of a wind turbine is modeled from a friction phenomenon perspective. Two models for the torque generated are proposed based on a relative speed between the wind and turbine blades. The main advantage of these models is the possibility of using real-time standard identification techniques for recovering their parameters value. Models are compared with a heuristic reference

  16. Torque Angle Loop Analysis of Synchronous Machines

    Microsoft Academic Search

    A. S. Gopala Rao; D. Thukaram; B. S. Ramakrishna Iyengar

    1986-01-01

    This paper reports the dynamic stability analysis of a single machine infinite bus system through torque angle loop analysis and forms an extension of the work on Block diagrams and torque angle loop analysis of synchronous machines reported by I. Nagy [3]. It aims to incorporate in the machine model, the damper windings (one on each axis) and to compare

  17. Fault-tolerant ripple-free torque control of brushless motors

    Microsoft Academic Search

    Farhad Aghili

    2010-01-01

    Fault tolerance is critical for servomotors used in high-risk applications, such as aerospace, robots, and military. These motors should be capable of continued functional operation even if insulation failure or open-circuit of a winding occur. This paper presents a fault-tolerant (FT) ripple-free torque controller for brushless DC (BLDC) motors that can maintain accurate torque production with minimum power dissipation even

  18. Quality of shrimp analogue product as affected by addition of modified potato starch.

    PubMed

    Remya, S; Basu, S; Venkateshwarlu, G; Mohan, C O

    2015-07-01

    The present study was aimed to investigate the effects of addition of modified potato starch on the biochemical and textural properties of shrimp analogue/imitation shrimp, a popular value-added product prepared from surimi. Three batches of shrimp analogues were prepared with 0 % (NPS), 50 % (CPS) and 100 % (MPS) of modified starch incorporation and various quality attributes were monitored at regular intervals during frozen storage (-20 °C). Loss of myofibrillar protein was least for the shrimp analogue sample added with 100 % modified potato starch. The expressible moisture content of MPS (2.48 %) was less affected by long term storage compared to CPS (3.38 %) and NPS (3.99 %). During extended low temperature storage, the textural quality of sea food analogue was highly influenced by the type of starch added to it. The percentage of modified potato starch added to shrimp analogue significantly (p???0.05) affected its hardness and fracturability. MPS samples did not show significant changes in hardness during storage as compared to other two samples. Springiness of shrimp analogue increased 2.57, 1.5 and 1.77 times with the storage period for samples with NPS, CPS and MPS, respectively. Addition of modified potato starch improved the sensory quality and textural properties of shrimp analogue and reduced the quality degradation during frozen storage as compared to NPS which contained only native potato starch. PMID:26139909

  19. In-line rotating capacitive torque sensor

    DOEpatents

    Kronberg, J.W.

    1991-09-10

    Disclosed are a method and apparatus for measuring torques developed along a rotating mechanical assembly comprising a rotating inner portion and a stationary outer portion. The rotating portion has an electrically-conductive flexing section fitted between two coaxial shafts in a configuration which varies radially in accordance with applied torque. The stationary portion comprises a plurality of conductive plates forming a surface concentric with and having a diameter slightly larger than the diameter of the rotating portion. The capacitance between the outer, nonrotating and inner, rotating portion varies with changes in the radial configuration of the rotating portion. Signal output varies approximately linearly with torque for small torques, nonlinearly for larger torques. The sensor is preferably surrounded by a conductive shell to minimize electrical interference from external sources. 18 figures.

  20. In-line rotating capacitive torque sensor

    DOEpatents

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

    1991-01-01

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

  1. An Exploration of U.S. Consumer Perceptions and Affect: Two Forms of a Soy-Based Food Product

    Microsoft Academic Search

    Marshall Ottenfeld; Donald Bernstein; Carl L. Witte

    2008-01-01

    This article focuses on a consumer comparison of fresh tofu and frozen tofu, and the investigation of consumer perceptions of and responses to, both products. A literature review of consumer perceptions and attitudes toward soy products was carried out. Consumer perceptions and affect were then qualitatively investigated using separate focus groups composed of “soy-users” and “health conscious” consumers. Extensive taste

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

    PubMed

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

    2014-02-01

    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

  3. 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

    2010-07-01

    ... true Minimum Data for Continuous...Limits for Tire Cord Production Affected Sources...Part 63—Minimum Data for Continuous...Limits for Tire Cord Production Affected Sources...maintain minimum data to show continuous...limits for tire cord production affected...

  4. Comparison of the MODIS Active Fire Product and Burned Area Product in Detecting Fire Affected Pixels in the Ecosystems of Belize 2003 - 2009 

    E-print Network

    van, Warmerdam

    2010-11-24

    The MODIS Active Fire Product (AFP) and the Burned Area Product (BAP) were used to analyze the spatial and temporal distribution of fire affected pixels in the ecosystems of Belize from 2003-2009. There was an overall trend of decreasing fire...

  5. Electric Field Driven Torque in Biological Rotary Motors

    E-print Network

    Miller,, John H; Maric, Sladjana; Infante, Hans L; Claycomb, James R

    2013-01-01

    Ion driven rotary motors, such as Fo-ATP synthase (Fo) and the bacterial flagellar motor, act much like a battery-powered electric motor. They convert energy from ions as they move from high to low potential across a membrane into torque and rotary motion. Here we propose a mechanism whereby electric fields, emanating from channels in one or more stators, act on asymmetric charge distributions due to protonated and deprotonated sites in the rotor and drive it to rotate. The model predicts an ideal scaling law between torque and ion motive force, which can be hindered by mitochondrial mutations. The rotor of Fo drives the gamma-subunit to rotate within the ATP-producing complex (F1), working against an opposing torque that rises and falls periodically with angular position. Drawing an analogy with Brownian motion of a particle in a tilted washboard potential, we compute the highly nonlinear ATP production rate vs. proton motive force (pmf), showing a minimum pmf needed to drive ATP production with important me...

  6. Switching Torque Converter: Concept and Preliminary Implementation

    NASA Astrophysics Data System (ADS)

    Hirota, Koichi; Ikei, Yasushi

    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.

  7. Magnetic torque on a rotating superconducting sphere

    NASA Technical Reports Server (NTRS)

    Holdeman, L. B.

    1975-01-01

    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.

  8. Torquing preload in a lubricated bolt

    NASA Technical Reports Server (NTRS)

    Seegmiller, H. L.

    1978-01-01

    The tension preload obtained by torquing a 7/8 in. diam UNC high strength bolt was determined for lubricated and dry conditions. Consistent preload with a variation of + or - 3% was obtained when the bolt head area was lubricated prior to each torque application. Preload tensions nearly 70% greater than the value predicted with the commonly used formula occurred with the lubricated bolt. A reduction to 39% of the initial preload was observed during 50 torque applications without relubrication. Little evidence of wear was noted after 203 cycles of tightening.

  9. How Fo-ATPase generates rotary torque.

    PubMed

    Oster, G; Wang, H; Grabe, M

    2000-04-29

    The F-ATPases synthesize ATP using a transmembrane ionmotive force (IMF) established by the electron transport chain. This transduction involves first converting the IMF to a rotary torque in the transmembrane Fo portion. This torque is communicated from Fo to the F1 portion where the energy is used to release the newly synthesized ATP from the catalytic sites according to Boyer's binding change mechanism. Here we explain the principle by which an IMF generates this rotary torque in the Fo ion engine. PMID:10836505

  10. Assessment of cultivation factors that affect biomass and geraniol production in transgenic tobacco cell suspension cultures.

    PubMed

    Vasilev, Nikolay; Schmitz, Christian; Grömping, Ulrike; Fischer, Rainer; Schillberg, Stefan

    2014-01-01

    A large-scale statistical experimental design was used to determine essential cultivation parameters that affect biomass accumulation and geraniol production in transgenic tobacco (Nicotiana tabacum cv. Samsun NN) cell suspension cultures. The carbohydrate source played a major role in determining the geraniol yield and factors such as filling volume, inoculum size and light were less important. Sucrose, filling volume and inoculum size had a positive effect on geraniol yield by boosting growth of plant cell cultures whereas illumination of the cultures stimulated the geraniol biosynthesis. We also found that the carbohydrates sucrose and mannitol showed polarizing effects on biomass and geraniol accumulation. Factors such as shaking frequency, the presence of conditioned medium and solubilizers had minor influence on both plant cell growth and geraniol content. When cells were cultivated under the screened conditions for all the investigated factors, the cultures produced ? 5.2 mg/l geraniol after 12 days of cultivation in shaking flasks which is comparable to the yield obtained in microbial expression systems. Our data suggest that industrial experimental designs based on orthogonal arrays are suitable for the selection of initial cultivation parameters prior to the essential medium optimization steps. Such designs are particularly beneficial in the early optimization steps when many factors must be screened, increasing the statistical power of the experiments without increasing the demand on time and resources. PMID:25117009

  11. ?? T cells affect IL-4 production and B-cell tolerance

    PubMed Central

    Huang, Yafei; Heiser, Ryan A.; Detanico, Thiago O.; Getahun, Andrew; Kirchenbaum, Greg A.; Casper, Tamara L.; Aydintug, M. Kemal; Carding, Simon R.; Ikuta, Koichi; Huang, Hua; Cambier, John C.; Wysocki, Lawrence J.; O’Brien, Rebecca L.; Born, Willi K.

    2015-01-01

    ?? T cells can influence specific antibody responses. Here, we report that mice deficient in individual ?? T-cell subsets have altered levels of serum antibodies, including all major subclasses, sometimes regardless of the presence of ?? T cells. One strain with a partial ?? deficiency that increases IgE antibodies also displayed increases in IL-4–producing T cells (both residual ?? T cells and ?? T cells) and in systemic IL-4 levels. Its B cells expressed IL-4–regulated inhibitory receptors (CD5, CD22, and CD32) at diminished levels, whereas IL-4–inducible IL-4 receptor ? and MHCII were increased. They also showed signs of activation and spontaneously formed germinal centers. These mice displayed IgE-dependent features found in hyper-IgE syndrome and developed antichromatin, antinuclear, and anticytoplasmic autoantibodies. In contrast, mice deficient in all ?? T cells had nearly unchanged Ig levels and did not develop autoantibodies. Removing IL-4 abrogated the increases in IgE, antichromatin antibodies, and autoantibodies in the partially ??-deficient mice. Our data suggest that ?? T cells, controlled by their own cross-talk, affect IL-4 production, B-cell activation, and B-cell tolerance. PMID:25535377

  12. Factors affecting yield and safety of protein production from cassava by Cephalosporium eichhorniae

    SciTech Connect

    Mikami, Y.; Gregory, K.F.; Levadoux, W.L.; Balagopalan, C.; Whitwill, S.T.

    1982-01-01

    The properties of C. eichhorniae 152 (ATCC 38255) affecting protein production from cassava carbohydrate, for use as an animal feed, were studied. This strain is a true thermophile, showing optimum growth at 45-47 degrees, maximum protein yield at 45 degrees, and no growth at 25 degrees. It has an optimum pH of approximately 3.8 and is obligately acidophilic, being unable to sustain growth at pH of more than or equal to 6.0 in a liquid medium, or pH of more than or equal to 7.0 on solid media. The optimum growth conditions of pH 3.8 and 45 degrees were strongly inhibitive to potential contaminants. It rapidly hydrolyzed cassava starch. It did not utilize sucrose, but approximately 16% of the small sucrose component of cassava was chemically hydrolyzed during the process. Growth with cassava meal (50 g/l) was complete in approximately 20 h, yielding 22.5 g/l (dry biomass), containing 41% crude protein (48-50% crude protein in the mycelium) and 31% true protein (7.0 g/l). Resting and germinating spores (10 to the power of 6 - 10 to the power of 8 per animal) injected by various routes into normal and gamma-irradiated 6-week-old mice and 7-day-old chickens failed to initiate infections.

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

    PubMed

    Chen, Yigen; Poland, Therese M

    2009-12-01

    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

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

    NASA Astrophysics Data System (ADS)

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

    2013-12-01

    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.

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

    SciTech Connect

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

    2010-12-15

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

  16. Particle Swarm Optimized Direct Torque Control of Induction Motors

    Microsoft Academic Search

    O. S. El-Laban; H. A. Abdel Fattah; H. M. Emara; A. F. Sakr

    2006-01-01

    The flux and torque hysteresis bands are the only adjustable parameters in direct torque control (DTC) of induction motors. Their selection greatly influences the inverter switching loss, motor harmonic loss and motor torque ripples, which are major performance criteria. In this paper, the effects of flux and torque hysteresis bands on these criteria are investigated and optimized via the minimization,

  17. Fourth-order acoustic torque in intense sound fields

    NASA Technical Reports Server (NTRS)

    Wang, T. G.; Kanber, H.; Olli, E. E.

    1978-01-01

    The observation of a fourth-order acoustic torque in intense sound fields is reported. The torque was determined by measuring the acoustically induced angular deflection of a polished cylinder suspended by a torsion fiber. This torque was measured in a sound field of amplitude greater than that in which first-order acoustic torque has been observed.

  18. Direct torque control of induction machines using space vector modulation

    Microsoft Academic Search

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

    1992-01-01

    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

  19. Torque ripple reduction in PMSM DTC drives using matrix converters

    Microsoft Academic Search

    Carlos Ortega; Antoni Arias; Cedric Caruana; Maurice Apap; Josep Balcells

    2007-01-01

    The paper investigates the use of the small voltage vectors of matrix converters (MC) in order to reduce the inherent torque ripple that appears when direct torque control (DTC) is used to control permanent magnets synchronous motors (PMSM). The new approach will differentiate between small and large torque errors, thus reducing the electromagnetic torque ripple. A comparison between the classical

  20. Damping assembly for a torque converter clutch

    SciTech Connect

    Dull, D.C.

    1989-12-26

    This patent describes a turbine damped torque converter and clutch. It comprises: a pressure plate; a torque converter turbine; a torque converter impeller; means including a control chamber for the pressure plate means for controlling the apply and release of the clutch for engaging the clutch with the impeller; a torque converter output shaft; a planetary gear arrangement including an input gear drivingly connected with the pressure plate, a reaction gear drivingly connected with the turbine, an output member drivingly connected with the output shaft and pinion gear means meshing with the input gear and the reaction gear for drivingly interconnecting the turbine and the pressure plate at a drive ratio of the turbine to the pressure plate of less than 1:1; and one-way drive means disposed between the turbine and the output shaft for preventing the turbine from overrunning the output shaft.

  1. Torque equilibrium attitude control for Skylab reentry

    NASA Technical Reports Server (NTRS)

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

    1979-01-01

    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.

  2. Improved computed torque control for industrial robots

    NASA Technical Reports Server (NTRS)

    Uebel, Mark; Minis, Ioannis; Cleary, Kevin

    1992-01-01

    The authors examine the computed torque control problem for a robot arm with flexible, geared, joint drive systems which are typical in many industrial robots. The standard computed torque algorithm is not directly applicable to this class of manipulators due to the dynamics introduced by the joint drive systems. The proposed approach overcomes this problem by combining a novel computed torque algorithm with simple torque controllers at each joint of the robot. The control scheme is applied to a seven degree-of-freedom industrial manipulator, and the system performance in standard tasks is evaluated using both dynamic simulation and actual experiments. The results show that the proposed controller leads to improved tracking performance over a conventional PD (proportional plus derivative) controller.

  3. 40 CFR 1065.310 - Torque calibration.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ...you calibrate the torque-measurement system with a reference force and a lever arm. (b) Recommended procedure to quantify lever-arm length. Quantify the lever-arm length, NIST-traceable within ±0.5% uncertainty. The...

  4. Selecting custom torque prescriptions for the straight-wire appliance.

    PubMed

    Johnson, Earl

    2013-04-01

    Selecting custom torque prescriptions based on the treatment needs of each patient can reduce the amount of routine archwire torque adjustment needed and speed torque correction, thus reducing the total treatment time. Using the appropriate torque prescription prevents iatrogenic torque problems and allows most torque corrections to be done earlier with more resilient nickel-titanium and beta-titanium wires. As a result, fewer time-consuming final torque adjustments are needed with stainless steel finishing wires, resulting in shorter treatment time. PMID:23540633

  5. Brake assembly including torque monitor

    SciTech Connect

    Dillmann, C.W.

    1992-07-21

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

  6. The Superrotation of Venus: Where's the Torque?

    E-print Network

    Chafin, Clifford

    2014-01-01

    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.

  7. Torque on an exoplanet from an anisotropic evaporative wind

    E-print Network

    Teyssandier, Jean; Adams, Fred C; Quillen, Alice C

    2015-01-01

    Winds from short-period Earth and Neptune mass exoplanets, driven by high energy radiation from a young star, may evaporate a significant fraction of a planet's mass. If the momentum flux from the evaporative wind is not aligned with the planet/star axis, then it can exert a torque on the planet's orbit. Using steady-state one-dimensional evaporative wind models we estimate this torque using a lag angle that depends on the product of the speed of the planet's upper atmosphere and a flow timescale for the wind to reach its sonic radius. We also estimate the momentum flux from time-dependent one-dimensional hydrodynamical simulations. We find that only in a very narrow regime in planet radius, mass and stellar radiation flux is a wind capable of exerting a significant torque on the planet's orbit. Similar to the Yarkovsky effect, the wind causes the planet to drift outward if atmospheric circulation is prograde (super-rotating) and in the opposite direction if the circulation is retrograde. A close-in super Ear...

  8. Knudsen torque on heated micro beams

    NASA Astrophysics Data System (ADS)

    Li, Qi; Liang, Tengfei; Ye, Wenjing

    2014-12-01

    Thermally induced mechanical loading has been shown to have significant effects on micro/nano objects immersed in a gas with a non-uniform 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. Using the asymptotic analysis in the near continuum regime, the Knudsen torque acting on an asymmetrically located uniformly heated microbeam in a cold enclosure is investigated. The existence of a non-zero net torque is demonstrated. In addition, it has been found that by manipulating the system configuration, the rotational direction of the torque can be changed. Two types of rotational motion of the microbeam have been identified: the pendulum motion of a rectangular beam, and the unidirectional rotation of a cylindrical beam. A rotational frequency of 4 rpm can be achieved for the cylindrical beam with a diameter of 3?m at Kn = 0.005. Illustrated by the simulations using the direct simulation of Monte Carlo, the Knudsen torque can be much increased in the transition regime, demonstrating the potential of Knudsen torque serving as a rotation engine for micro/nano objects.

  9. Microbiological and physicochemical factors affecting Aspergillus section Flavi incidence in Cavendish banana ( Musa cavendishii ) chips production in Southern Philippines

    Microsoft Academic Search

    A. C. Sales; P. V. Azanza; T. Yoshizawa

    2005-01-01

    Microbiological and physicochemical factors affecting the incidence of Aspergillus section Flavi in dried Cavendish banana (Musa cavendishii) chips production in Southern Philippines were examined. The average counts of Aspergillus section Flavi (AFC) in fresh and dried Cavendish bananas from 10 production batches of the Philippine Agro-Industrial Development Cooperative in Davao del Norte, Southern Philippines were 1.2 × 102 and 1.6

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

    PubMed Central

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

    2011-01-01

    The objective of this study was to determine whether 5-lipoxygenase (ALOX5) gene variants associated with cardiovascular disease affect eicosanoid production by monocytes. The study was a randomized, double-masked, parallel intervention trial with fish oil (5.0 g of fish oil daily, containing 2.0 g of eicosapentaenoic acid [EPA] and 1.0 g of docosahexaenoic acid [DHA]) or placebo oil (5.0 g of corn/soy mixture). A total of 116 subjects (68% female, 20–59 years old) of African American ancestry enrolled, and 98 subjects completed the study. Neither ALOX5 protein nor arachidonic acid-derived LTB4, LTD4, and LTE4 varied by genotype, but 5-hydroxyeicosatetraenoate (5-HETE), 6-trans-LTB4, 5-oxo-ETE, 15-HETE, and 5,15-diHETE levels were higher in subjects homozygous for the ALOX5 promoter allele containing five Sp1 element tandem repeats (“55” genotype) than in subjects with one deletion (d) (three or four repeats) and one common (“d5” genotype) allele or with two deletion (“dd”) alleles. The EPA-derived metabolites 5-HEPE and 15-HEPE and the DHA-derived metabolite 17-HDoHE had similar associations with genotype and increased with supplementation; 5-HEPE and 15-HEPE increased, and 5-oxo-ETE decreased to a greater degree in the 55 than in the other genotypes. This differential eicosanoid response is consistent with the previously observed interaction of these variants with dietary intake of omega-3 fatty acids in predicting cardiovascular disease risk. PMID:21296957

  11. Do labour productivity and preferences about work load distribution affect reproduction management and performance in pig farms

    Microsoft Academic Search

    G. Martel; J.-Y. Dourmad; B. Dedieu

    2008-01-01

    Increases in labour productivity are essential factors, as well as technical effectiveness, for the competitiveness of pig farming. However, the preferences of farmers for controlled (i.e. limited) daily working hours or available days for vacation also increase. The objective of this study was to explore how these preferences about work might be associated to specific combinations of practices or affect

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

    E-print Network

    Kroeger, Timothy H

    2013-09-19

    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...

  13. A method to accurately estimate the muscular torques of human wearing exoskeletons by torque sensors.

    PubMed

    Hwang, Beomsoo; Jeon, Doyoung

    2015-01-01

    In exoskeletal robots, the quantification of the user's muscular effort is important to recognize the user's motion intentions and evaluate motor abilities. In this paper, we attempt to estimate users' muscular efforts accurately using joint torque sensor which contains the measurements of dynamic effect of human body such as the inertial, Coriolis, and gravitational torques as well as torque by active muscular effort. It is important to extract the dynamic effects of the user's limb accurately from the measured torque. The user's limb dynamics are formulated and a convenient method of identifying user-specific parameters is suggested for estimating the user's muscular torque in robotic exoskeletons. Experiments were carried out on a wheelchair-integrated lower limb exoskeleton, EXOwheel, which was equipped with torque sensors in the hip and knee joints. The proposed methods were evaluated by 10 healthy participants during body weight-supported gait training. The experimental results show that the torque sensors are to estimate the muscular torque accurately in cases of relaxed and activated muscle conditions. PMID:25860074

  14. A Method to Accurately Estimate the Muscular Torques of Human Wearing Exoskeletons by Torque Sensors

    PubMed Central

    Hwang, Beomsoo; Jeon, Doyoung

    2015-01-01

    In exoskeletal robots, the quantification of the user’s muscular effort is important to recognize the user’s motion intentions and evaluate motor abilities. In this paper, we attempt to estimate users’ muscular efforts accurately using joint torque sensor which contains the measurements of dynamic effect of human body such as the inertial, Coriolis, and gravitational torques as well as torque by active muscular effort. It is important to extract the dynamic effects of the user’s limb accurately from the measured torque. The user’s limb dynamics are formulated and a convenient method of identifying user-specific parameters is suggested for estimating the user’s muscular torque in robotic exoskeletons. Experiments were carried out on a wheelchair-integrated lower limb exoskeleton, EXOwheel, which was equipped with torque sensors in the hip and knee joints. The proposed methods were evaluated by 10 healthy participants during body weight-supported gait training. The experimental results show that the torque sensors are to estimate the muscular torque accurately in cases of relaxed and activated muscle conditions. PMID:25860074

  15. Force, Torque and Stiffness: Interactions in Perceptual Discrimination

    PubMed Central

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

    2011-01-01

    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

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

    NASA Technical Reports Server (NTRS)

    Bartos, R. D.

    1992-01-01

    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.

  17. Torque shudder protection device and method

    DOEpatents

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

    1997-03-11

    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.

  18. Torque converter slipping clutch and control

    SciTech Connect

    Wonn, Q.E.

    1987-02-17

    This patent describes a controlled slip torque converter and clutch comprising; an input shell; a torque converter means having an impeller drivingly connected with the input shell, a turbine and a stator disposed for toroidal flow, the torque converter means transmitting drive torque from the impeller to the turbine in a slipping relation; clutch means engageable in response to fluid pressure to limit the slip relation between the impeller and turbine and being disposed in drive relation between the input shell and the turbine and cooperating therewith to form clutch apply chamber means and clutch release chamber means; variable flow restriction means including spring means disposed between the clutch apply chamber means and the release chamber means for providing a controlled flow from the apply chamber means to the release chamber means; and viscous damper means disposed in parallel relation with the spring means on the variable flow restriction means and being responsive to torque disturbances at the clutch means and the turbine to restrict the rate at which the flow restriction means varies.

  19. Torque shudder protection device and method

    DOEpatents

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

    1997-01-01

    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.

  20. Factors Affecting Carbohydrate Production and the Formation of Transparent Exopolymer Particles (TEP) by Diatoms 

    E-print Network

    Chen, Jie

    2014-03-25

    Diatoms exude large amounts of exopolymers (EPS), which are predominantly composed of carbohydrates. EPS may coagulate into transparent exopolymer particles (TEP). Sticky TEP affects the formation of aggregates and marine snow, and consequently...

  1. Measurement of torque in steam turbine-generator shafts following severe disturbances on the electrical supply system; Analysis and implementation

    SciTech Connect

    Hammons, T.J. (Dept. of Electronics and Electrical Engineering, Glasgow Univ., Glasgow G12 8QQ (GB)); Chanal, L. (Ecole Nationale Superieure d'Ingenieurs Electriciens de Grenoble (FR))

    1991-03-01

    The paper reviews phenomena that affects performance of transducers that measure torque at positions along a turbine-generator shaft, and then describes the design of a transducer for precise measurement of torque at positions on a steam turbine-generator shaft that results from severe disturbances on the electrical supply system. Torque at shaft couplings following severe supply system events predicted using continuum models of turbine-generator shafts is analyzed and compared with that obtained over a section of the shaft by shaft twist and overall stiffness of the section. Algorithms for processing torque deduced from twist over a section of shaft to estimate true torque at specific shaft locations are discussed. Studies are performed to severe L-L-L short circuits with clearance. The paper describes the design of a transient shaft torque transducer which uses discs, with slits, which are secured to the rotating shaft. The time interval between pulses obtained when slits pass transducers are measured and compared with the time intervals which correspond to zero torque so as to calibrate the measurements.

  2. Torque limit of PM motors for field-weakening region operation

    DOEpatents

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

    2012-02-14

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

  3. Manipulation of Magnetic Insulators Using Spin Torque from the Spin Hall Effect

    NASA Astrophysics Data System (ADS)

    Jermain, Colin; Paik, Hanjong; Heron, John; Aradhya, Sriharsha; Schlom, Darrell; Ralph, Dan

    2014-03-01

    We will report the growth and fabrication of devices incorporating thin films of the magnetic insulators yttrium iron garnet and lutetium iron garnet with thicknesses less than 20 nm. We perform the growth using oxide MBE, achieving high-quality films with magnetic damping parameters for single 5 nm films as small as 0.00036. We use electron beam lithography and ion milling to pattern the films into device structures with sizes ranging from 100 nm to above 1 micron, integrated with Ta contacts so that we can use the spin Hall effect to apply spin-transfer torque to the magnetic materials. We will use these devices to study how the spin Hall torque affects the effective magnetic damping parameter of isolated magnetic insulator devices, and whether spin Hall torque can be used to drive reliable magnetic switching in these materials at low current levels.

  4. AX-5 space suit bearing torque investigation

    NASA Technical Reports Server (NTRS)

    Loewenthal, Stuart; Vykukal, Vic; Mackendrick, Robert; Culbertson, Philip, Jr.

    1990-01-01

    The symptoms and eventual resolution of a torque increase problem occurring with ball bearings in the joints of the AX-5 space suit are described. Starting torques that rose 5 to 10 times initial levels were observed in crew evaluation tests of the suit in a zero-g water tank. This bearing problem was identified as a blocking torque anomaly, observed previously in oscillatory gimbal bearings. A large matrix of lubricants, ball separator designs and materials were evaluated. None of these combinations showed sufficient tolerance to lubricant washout when repeatedly cycled in water. The problem was resolved by retrofitting a pressure compensated, water exclusion seal to the outboard side of the bearing cavity. The symptoms and possible remedies to blocking are discussed.

  5. Thomas precession: Where is the torque

    SciTech Connect

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

    1992-04-01

    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.

  6. Peak torque and rate of torque development influence on repeated maximal exercise performance: contractile and neural contributions.

    PubMed

    Morel, Baptiste; Rouffet, David M; Saboul, Damien; Rota, Samuel; Clémençon, Michel; Hautier, Christophe A

    2015-01-01

    Rapid force production is critical to improve performance and prevent injuries. However, changes in rate of force/torque development caused by the repetition of maximal contractions have received little attention. The aim of this study was to determine the relative influence of rate of torque development (RTD) and peak torque (T(peak)) on the overall performance (i.e. mean torque, T(mean)) decrease during repeated maximal contractions and to investigate the contribution of contractile and neural mechanisms to the alteration of the various mechanical variables. Eleven well-trained men performed 20 sets of 6-s isokinetic maximal knee extensions at 240° · s(-1), beginning every 30 seconds. RTD, T(peak) and T(mean) as well as the Rate of EMG Rise (RER), peak EMG (EMG(peak)) and mean EMG (EMG(mean)) of the vastus lateralis were monitored for each contraction. A wavelet transform was also performed on raw EMG signal for instant mean frequency (if(mean)) calculation. A neuromuscular testing procedure was carried out before and immediately after the fatiguing protocol including evoked RTD (eRTD) and maximal evoked torque (eT(peak)) induced by high frequency doublet (100 Hz). T(mean) decrease was correlated to RTD and T(peak) decrease (R(²) = 0.62; p<0.001; respectively ?=0.62 and ?=0.19). RER, eRTD and initial if(mean) (0-225 ms) decreased after 20 sets (respectively -21.1 ± 14.1, -25 ± 13%, and ~20%). RTD decrease was correlated to RER decrease (R(²) = 0.36; p<0.05). The eT(peak) decreased significantly after 20 sets (24 ± 5%; p<0.05) contrary to EMG(peak) (-3.2 ± 19.5 %; p=0.71). Our results show that reductions of RTD explained part of the alterations of the overall performance during repeated moderate velocity maximal exercise. The reductions of RTD were associated to an impairment of the ability of the central nervous system to maximally activate the muscle in the first milliseconds of the contraction. PMID:25901576

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

    NASA Astrophysics Data System (ADS)

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

    2014-05-01

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

  8. Joint torques and powers are reduced during ambulation for both limbs in patients with unilateral claudication

    PubMed Central

    Koutakis, Panagiotis; Pipinos, Iraklis I.; Myers, Sara A.; Stergiou, Nicholas; Lynch, Thomas G.; Johanning, Jason M.

    2015-01-01

    Objectives Symptomatic peripheral arterial disease (PAD) results in significant gait impairment. In an attempt to fully delineate and quantify these gait alterations, we analyzed joint kinematics, torques (rotational forces) and powers (rotational forces times angular velocity) in PAD patients with unilateral claudication for both the affected and non-affected legs. Methods Twelve patients with unilateral PAD (age: 61.69±10.53 years, ABI: Affected Limb 0.59 ± 0.25; Non-Affected Limb 0.93 ± 0.12) and ten healthy controls (age: 67.23 ± 12.67 years, ABI>1.0 all subjects) walked over a force platform to acquire gait kinetics, while joint kinematics were recorded simultaneously. Data were collected for the affected and non-affected limbs during pain free (PAD-PF) and pain induced (PAD-P) trials. Kinetics and kinematics were combined to quantify torques and powers during the stance period from the hip, knee, and ankle joints. Results The affected limb demonstrated significantly (p<0.05) reduced ankle plantar flexion torque compared to control during late stance in both PAD-PF and PAD-P trials. There were significant reductions in ankle plantar flexion power generation during late stance for both the affected (P<.05) and non-affected limbs (P<.05) compared to control during PAD-PF and PAD-P trials. No significant differences were noted in torques comparing the non-affected limb in PAD-PF and PAD-P conditions to control for knee and hip joints throughout the stance phase. Significant reductions were found in knee power absorption in early stance and knee power generation during mid stance for both limbs of the PAD patients as compared to control (P<.05). Conclusions PAD patients with unilateral claudication demonstrate significant gait impairments in both limbs that are present even before they experience any claudication symptoms. Overall, our data demonstrate significantly reduced ankle plantar flexion torque and power during late stance with reduced knee power during early and mid stance for the affected limb. Further studies are needed to determine if these findings dependent on the location and the severity of lower extremity ischemia and whether the changes in the non-affected limb are the result of underlying PAD or compensatory changes from the affected limb dysfunction. PMID:19837536

  9. Distribution and abundance of predators that affect duck production--prairie pothole region

    USGS Publications Warehouse

    Sargeant, A.B.; Greenwood, R.J.; Sovada, M.A.; Shaffer, T.L.

    1993-01-01

    During 1983-88, the relative abundance of 18 species and species-groups of mammalian and avian predators affecting duck production in the prairie pothole region was determined in 33 widely scattered study areas ranging in size from 23-26 km2. Accounts of each studied species and species-group include habitat and history, population structure and reported densities, and information on distribution and abundance from the present study. Index values of undetected, scarce, uncommon, common, or numerous were used to rate abundance of nearly all species in each study area. Principal survey methods were livetrapping of striped skunks (Mephitis mephitis) and Franklin's ground squirrels (Spermophilus franklinii), systematic searches for carnivore tracks in quarter sections (0.65 km2), daily records of sightings of individual predator species, and systematic searches for occupied nests of tree-nesting avian predators. Abundances of predators in individual areas were studied 1-3 years.The distribution and abundance of predator species throughout the prairie pothole region have undergone continual change since settlement of the region by Europeans in the late 1800's. Predator populations in areas we studied differed markedly from those of pristine times. The changes occurred from habitat alterations, human-inflicted mortality of predators, and interspecific relations among predator species. Indices from surveys of tracks revealed a decline in the abundance of red foxes (Vulpes vulpes) and an albeit less consistent decline in the abundance of raccoons (Procyon lotor) with an increase in the abundance of coyotes (Canis latrans). Records of locations of occupied nests revealed great horned owls (Bubo virginianus) and red-tailed hawks (Buteo jamaicensis) tended to nest 0.5 km apart, and American crows (Corvus brachyrhynchos) tended to avoid nesting 0.5 km of nests of red-tailed hawks. Excluding large gulls, for which no measurements of abundance were obtained, the number of predator species averaged 12.2 (SD = 1.60) per study area; common or numerous predator species averaged 6.0 (SD = 1.54) per study area (minimal because the abundance of weasels [Mustela erminea; M. frenata] in all areas and of minks [Mustela vison] and raptors in some areas was not rated). Major changes in relative abundance of individual predator species studied >1 year were few. Predator species most restricted to the aspen parkland were the Franklin's ground squirrel, black-billed magpie (Pica pica), American crow (Corvus brachyrlus), and red-tailed hawk; species most restricted to the prairie were the badger (Taxidea taxus), Swainson's hawk (Buteo swainsoni), and ferruginous hawk (B. regalis). The coyote, black-billed magpie, and American crow were most numerous in Canada, whereas the red fox, raccoon, mink, ferruginous hawk, and great horned owl were most numerous in the United States. The number of common or numerous egg-eating predator species (excludes large gulls and weasels, which were not rated) averaged 4.6 (SD = 0.90) per study area. The average numbers of common or numerous egg-eating species per study area did not differ among provinces and states, but birds gradually replaced mammals from southeast to northwest across the region. Investigators are urged to assess composition of predator populations and relative abundance of predator species for evaluations of waterfowl recruitment.

  10. Torque detected broad band electron spin resonance

    NASA Astrophysics Data System (ADS)

    El Hallak, Fadi; van Slageren, Joris; Dressel, Martin

    2010-09-01

    We present a novel technique to measure high frequency electron spin resonance spectra in a broad frequency range (30-1440 GHz) with high sensitivity. We use a quasioptical setup with tunable frequency sources to induce magnetic resonance transitions. These transitions are detected by measuring the change in the magnetic torque signal by means of cantilever torque magnetometry. The setup allows tuning of the frequency, magnetic field, polarization, and the angle between the sample and the external magnetic field. We demonstrate the capabilities of this technique by showing preliminary results obtained on a single crystal of an Fe4 molecular nanomagnet.

  11. Galactoglucomannan Oligosaccharide Supplementation Affects Nutrient Digestibility, Fermentation End-Product Production, and Large Bowel Microbiota of the Dog

    Technology Transfer Automated Retrieval System (TEKTRAN)

    A galactoglucomannan oligosaccharide (GGMO) obtained from fiberboard production was evaluated as a dietary supplement for dogs. The GGMO substrate contained high concentrations of oligosaccharides containing mannose, xylose, and glucose, with the mannose component accounting for 35% of dry matter. ...

  12. They Raise Them Differently Up North - Different Production Practices in Australian Growing Areas May Affect Mycorrhizae

    Technology Transfer Automated Retrieval System (TEKTRAN)

    This report briefly summarizes the results from a survey to determine cultural blueberry practices and production differences used in New South Wales (NSW), Victoria, Tasmania, and Queensland. The purpose of the survey was to collect information on a number of production practices that had been s...

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

    Microsoft Academic Search

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

    2011-01-01

    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

  14. Genetic, Physiological, and Environmental Factors Affecting Acrylamide Concentration in Fried Potato Products

    Technology Transfer Automated Retrieval System (TEKTRAN)

    The discovery of acrylamide in processed potato products has brought increased interest in the controlling Maillard reaction precursors (reducing sugars and amino acids) in potato tubers. Because of their effects on nonenzymatic browning of fried potato products, reducing sugars and amino acids have...

  15. INDUSTRIAL AND MUNICIPAL BY-PRODUCTS AS SOIL SUPPLEMENTS AFFECT BLUEBERRY FRUIT QUALITY

    Technology Transfer Automated Retrieval System (TEKTRAN)

    The effect of industrial and municipal by-products as constituents in soil-free media and as soil supplements on fruit quality of highbush blueberry (Vaccinium corymbosum L.) were evaluated in this study. These by-products include coal ash, composted sewage and leaf compost. Combinations of ash and ...

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

    PubMed

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

    2014-07-01

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

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

    Microsoft Academic Search

    Simon P Elliott

    2003-01-01

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

  18. How body mass and lifestyle affect juvenile biomass production in placental mammals

    PubMed Central

    Sibly, Richard M.; Grady, John M.; Venditti, Chris; Brown, James H.

    2014-01-01

    In mammals, the mass-specific rate of biomass production during gestation and lactation, here called maternal productivity, has been shown to vary with body size and lifestyle. Metabolic theory predicts that post-weaning growth of offspring, here termed juvenile productivity, should be higher than maternal productivity, and juveniles of smaller species should be more productive than those of larger species. Furthermore because juveniles generally have similar lifestyles to their mothers, across species juvenile and maternal productivities should be correlated. We evaluated these predictions with data from 270 species of placental mammals in 14 taxonomic/lifestyle groups. All three predictions were supported. Lagomorphs, perissodactyls and artiodactyls were very productive both as juveniles and as mothers as expected from the abundance and reliability of their foods. Primates and bats were unproductive as juveniles and as mothers, as expected as an indirect consequence of their low predation risk and consequent low mortality. Our results point the way to a mechanistic explanation for the suite of correlated life-history traits that has been called the slow–fast continuum. PMID:24403339

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

    PubMed Central

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

    2008-01-01

    Liquid and solid foods are documented to elicit differential appetitive and food intake responses. This study was designed to assess the influences of liquid vs solid meal replacement products on postprandial appetite ratings and subsequent food intake in healthy older adults. This study used a randomized and crossover design with two 1-day trials (1 week between trials), and 24 adults (12 men and 12 women) aged 50 to 80 years with body mass index (calculated as kg/m2) between 22 and 30 participated. After an overnight fast, the subjects consumed meal replacement products as either a beverage (liquid) or a bar (solid). The meal replacement products provided 25% of each subject's daily estimated energy needs with comparable macro-nutrient compositions. Subjects rated their appetite on a 100 mm quasilogarithmic visual analog scale before and 15, 30, 45, 60, 90, 120, and 150 minutes after consuming the meal replacement product. At minute 120, each subject consumed cooked oatmeal ad libitum to a “comfortable level of fullness.” Postprandial composite (area under the curve from minute 15 to minute 120) hunger was higher (P=0.04) for the liquid vs solid meal replacement products and desire to eat (P=0.15), preoccupation with thoughts of food (P=0.07), and fullness (P=0.25) did not differ for the liquid vs solid meal replacement products. On average, the subjects consumed 13.4% more oatmeal after the liquid vs solid (P=0.006) meal replacement product. These results indicate that meal replacement products in liquid and solid form do not elicit comparable appetitive and ingestive behavior responses and that meal replacement products in liquid form blunt the postprandial decline in hunger and increase subsequent food intake in older adults. PMID:18589034

  20. 14 CFR 39.17 - What must I do if a change in a product affects my ability to accomplish the actions required in...

    Code of Federal Regulations, 2012 CFR

    2012-01-01

    ... 2012-01-01 false What must I do if a change in a product affects...AIRWORTHINESS DIRECTIVES § 39.17 What must I do if a change in a product affects...alternative method of compliance. Unless you can show the change eliminated the...

  1. 14 CFR 39.17 - What must I do if a change in a product affects my ability to accomplish the actions required in...

    Code of Federal Regulations, 2011 CFR

    2011-01-01

    ... 2011-01-01 false What must I do if a change in a product affects...AIRWORTHINESS DIRECTIVES § 39.17 What must I do if a change in a product affects...alternative method of compliance. Unless you can show the change eliminated the...

  2. 14 CFR 39.17 - What must I do if a change in a product affects my ability to accomplish the actions required in...

    Code of Federal Regulations, 2013 CFR

    2013-01-01

    ... 2013-01-01 false What must I do if a change in a product affects...AIRWORTHINESS DIRECTIVES § 39.17 What must I do if a change in a product affects...alternative method of compliance. Unless you can show the change eliminated the...

  3. 14 CFR 39.17 - What must I do if a change in a product affects my ability to accomplish the actions required in...

    Code of Federal Regulations, 2014 CFR

    2014-01-01

    ... 2014-01-01 false What must I do if a change in a product affects...AIRWORTHINESS DIRECTIVES § 39.17 What must I do if a change in a product affects...alternative method of compliance. Unless you can show the change eliminated the...

  4. Does selection for production traits affect the ability to cope with pathogens? 

    E-print Network

    Coltherd, Jennifer Carolyn

    2011-06-27

    Phenotypic selection for production traits causes changes in the underlying genetics of the animal. As such, intensive selection on one trait may have consequences on other traits. Indeed alterations to traits seemingly unrelated to the desirable...

  5. 75 FR 27614 - WTO Dispute Settlement Proceeding Regarding United States-Measures Affecting the Production and...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2010-05-17

    ...including clove, but would continue to permit the production and sale of other cigarettes, including cigarettes containing menthol, beginning 90 days after the legislation was signed into law. Indonesia appears to allege that this provision of the...

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

    E-print Network

    Wilson, Carolyn E.

    2010-10-12

    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...

  7. System to Produce Mechanical Inertial Force and\\/or Torque

    Microsoft Academic Search

    Dan Ciulin

    2008-01-01

    The Top and\\/or the gyroscope are devices able to produce inertial torques that maintains their direction in space if no external\\u000a torques are applied. The resulted inertial torques are based on Coriolis forces. Two gyroscopes, placed as near as possible\\u000a on a platform, may be used as a ‘doublet’ to produce inertial forces and\\/or torques. As the gyroscope is a

  8. Factors affecting the production of terpenes in seedlings of Pinus elliottii 

    E-print Network

    Ishihara, Hiroichi

    1987-01-01

    of terpenes was calculated using an internal standard, and data were subjected to statistical tests. For seedlings in the greenhouse, terpene content increased with seedling age. Upon wounding the seedlings, total resin acid production increased... 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...

  9. A surprising observation that oxygen can affect the product enantiopurity of an enzyme-catalysed reaction.

    PubMed

    Fryszkowska, Anna; Toogood, Helen S; Mansell, David; Stephens, Gill; Gardiner, John M; Scrutton, Nigel S

    2012-11-01

    Enzymes are natural catalysts, controlling reactions with typically high stereospecificity and enantiospecificity in substrate selection and/or product formation. This makes them useful in the synthesis of industrially relevant compounds, particularly where highly enantiopure products are required. The flavoprotein pentaerythritol tetranitrate (PETN) reductase is a member of the Old Yellow Enzyme family, and catalyses the asymmetric reduction of ?-alkyl-?-arylnitroalkenes. Under aerobic conditions, it additionally undergoes futile cycles of NAD(P)H reduction of flavin, followed by reoxidation by oxygen, which generates the reactive oxygen species (ROS) hydrogen peroxide and superoxide. Prior studies have shown that not all reactions catalysed by PETN reductase yield enantiopure products, such as the reduction of (E)-2-phenyl-1-nitroprop-1-ene (PNE) to produce (S)-2-phenyl-1-nitropropane (PNA) with variable enantiomeric excess (ee). Recent independent studies of (E)-PNE reduction by PETN reductase showed that the major product formed could be switched to (R)-PNA, depending on the reaction conditions. We investigated this phenomenon, and found that the presence of oxygen and ROS influenced the overall product enantiopurity. Anaerobic reactions produced consistently higher nitroalkane (S)-PNA product yields than aerobic reactions (64% versus 28%). The presence of oxygen dramatically increased the preference for (R)-PNA formation (up to 52% ee). Conversely, the presence of the ROS superoxide and hydrogen peroxide switched the preference to (S)-PNA product formation. Given that oxygen has no role in the natural catalytic cycle, these findings demonstrate a remarkable ability to manipulate product enantiopurity of this enzyme-catalysed reaction by simple manipulation of reaction conditions. Potential mechanisms of this unusual behaviour are discussed. PMID:22978386

  10. Manure Phosphorus Extractability as Affected by Aluminum and Iron By-Products and Aerobic Composting

    Microsoft Academic Search

    Thanh H. Dao; L. J. Sikora; A. Hamasaki; R. L. Chaney

    2001-01-01

    manure, respectively. The by-products also reduced the 0.5 M NH4F- extractable phosphorus (FEP) fraction. Shifts in P forms between Miller, 1994). The Al 3 reacted with ammonia released FEP and 0.1 M NaOH-extractable phosphorus (SHEP) depended during the decomposition of uric acid and organic N upon the Al and Fe contents of the by-products while the combined in poultry manure.

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

    Microsoft Academic Search

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

    2012-01-01

    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

  12. Petunia?×?hybrida floral scent production is negatively affected by high-temperature growth conditions.

    PubMed

    Cna'ani, Alon; Mühlemann, Joelle K; Ravid, Jasmin; Masci, Tania; Klempien, Antje; Nguyen, Thuong T H; Dudareva, Natalia; Pichersky, Eran; Vainstein, Alexander

    2015-07-01

    Increasing temperatures due to changing global climate are interfering with plant-pollinator mutualism, an interaction facilitated mainly by floral colour and scent. Gas chromatography-mass spectroscopy analyses revealed that increasing ambient temperature leads to a decrease in phenylpropanoid-based floral scent production in two Petunia?×?hybrida varieties, P720 and Blue Spark, acclimated at 22/16 or 28/22?°C (day/night). This decrease could be attributed to down-regulation of scent-related structural gene expression from both phenylpropanoid and shikimate pathways, and up-regulation of a negative regulator of scent production, emission of benzenoids V (EOBV). To test whether the negative effect of increased temperature on scent production can be reduced in flowers with enhanced metabolic flow in the phenylpropanoid pathway, we analysed floral volatile production by transgenic 'Blue Spark' plants overexpressing CaMV 35S-driven Arabidopsis thaliana production of anthocyanin pigments 1 (PAP1) under elevated versus standard temperature conditions. Flowers of 35S:PAP1 transgenic plants produced the same or even higher levels of volatiles when exposed to a long-term high-temperature regime. This phenotype was also evident when analysing relevant gene expression as inferred from sequencing the transcriptome of 35S:PAP1 transgenic flowers under the two temperature regimes. Thus, up-regulation of transcription might negate the adverse effects of temperature on scent production. PMID:25402319

  13. Factors affecting mycelial biomass and exopolysaccharide production in submerged cultivation of Antrodia cinnamomea using complex media.

    PubMed

    Lin, En-Shyh; Chen, Yueh-Hsiang

    2007-09-01

    Submerged cultures were used to identify growth-limiting nutrients by Antrodia cinnamomea strains. The mycelial biomass and EPS production by A. cinnamomea BCRC 35396 were markedly higher than other A. cinnamomea strains. A relatively high C/N ratio was favorable for both the mycelial growth (5.41 g/l) and EPS production (0.55 g/l); the optimum ratio was 40. The glucose was available utilized preferentially for mycelial growth, rather than for EPS production. Flushing the culture medium with nitrogen had a stimulating effect on both mycelial growth and EPS production. In addition, peptone, yeast extract and malt extract appeared to be important and significant component for EPS production. Phosphate ion, magnesium ion and thiamine were probably not essential for mycelial growth. By optimizing the effects of additional nutrition, the results showed that 5% (w/v) glucose, 0.8% (w/v) peptone, 0.8% (w/v) yeast extract, 0.8% (w/v) malt extract, 0.03% (w/v) KH2PO4, 0.1% (w/v) MgSO4 .7H2O and 0.1% (w/v) thiamine could lead to the maximum production of EPS (1.36 g/l). PMID:17071080

  14. A force and torque tensegrity sensor

    Microsoft Academic Search

    Cornel Sultan; Robert Skelton

    2004-01-01

    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

  15. Torque-balanced vibrationless rotary coupling

    DOEpatents

    Miller, Donald M. (Sunnyside, WA)

    1980-01-01

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

  16. Design and Development of Torque Controlled Joints

    Microsoft Academic Search

    Dieter Vischer; Oussama Khatib

    1989-01-01

    This paper discusses the effect of basic manipulator characteristics upon the implementation of high performance joint torque control. Two manipulators with very different characteristics (high and low gear ratios) are used in this analysis: The PUMA 560 manipulator and ARTISAN, a ten degree-of-freedom manipulator currently under development at Stanford. The experimental results obtained with a prototype link of ARTISAN are

  17. Torque Limits for Fasteners in Composites

    NASA Technical Reports Server (NTRS)

    Zhao, Yi

    2002-01-01

    The two major classes of laminate joints are bonded and bolted. Often the two classes are combined as bonded-bolted joints. Several characteristics of fiber reinforced composite materials render them more susceptible to joint problems than conventional metals. These characteristics include weakness in in-plane shear, transverse tension/compression, interlaminar shear, and bearing strength relative to the strength and stiffness in the fiber direction. Studies on bolted joints of composite materials have been focused on joining assembly subject to in-plane loads. Modes of failure under these loading conditions are net-tension failure, cleavage tension failure, shear-out failure, bearing failure, etc. Although the studies of torque load can be found in literature, they mainly discussed the effect of the torque load on in-plane strength. Existing methods for calculating torque limit for a mechanical fastener do not consider connecting members. The concern that a composite member could be crushed by a preload inspired the initiation of this study. The purpose is to develop a fundamental knowledge base on how to determine a torque limit when a composite member is taken into account. Two simplified analytical models were used: a stress failure analysis model based on maximum stress criterion, and a strain failure analysis model based on maximum strain criterion.

  18. Noncontact Measurements Of Torques In Shafts

    NASA Technical Reports Server (NTRS)

    Schwartzbart, Aaron

    1991-01-01

    Additional information extracted from eddy-current proximeter. Positioned over rotating shaft, measures both displacement of and torsion in shaft. Torque applied to shaft calculable from output of proximeter. Possible to extract torsion information from existing tape-recorded proximeter data.

  19. Torque, Tension, And Friction In Bolts

    NASA Technical Reports Server (NTRS)

    Morawski, Julian

    1992-01-01

    Improved equations predict relationships among tension in bolt, torque applied to bolt during installation, effective coefficient of friction, and number of times bolt has been installed. Bolted joints designed with new equations, use fewer and/or smaller bolts to carry same loads, reducing weights.

  20. Torque wrench allows readings from inaccessible locations

    NASA Technical Reports Server (NTRS)

    De Barnardo, M.

    1966-01-01

    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.

  1. A New Twist on Torque Labs

    ERIC Educational Resources Information Center

    Lane, W. Brian

    2014-01-01

    The traditional introductory-level meterstick-balancing lab assumes that students already know what torque is and that they readily identify it as a physical quantity of interest. We propose a modified version of this activity in which students qualitatively and quantitatively measure the amount of force required to keep the meterstick level. The…

  2. Torque and First-Class Levers

    NSDL National Science Digital Library

    Michael Horton

    2009-05-30

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

  3. Compliant Gearing For Redundant Torque Drive

    NASA Technical Reports Server (NTRS)

    Isabelle, C.; Kish, J.

    1993-01-01

    Elastomeric bearings make torque loads more nearly equal. Bearings couple drive shaft with ring spur gear. Inner elastomeric bearing radially stiff and circumferentially compliant, while outer elastomeric bearings circumferentially stiff and radially compliant. Combination accommodates minor variations in dimensions and placements of gears, shafts, and other components.

  4. Isokinetic Peak Torque in Young Wrestlers

    E-print Network

    Housh, Terry J.; Johnson, Glen O.; Housh, Dona J.; Stout, Jeffrey R.; Weir, Joseph P.; Weir, Loree L.; Eckerson, Joan M.

    1996-01-01

    The purpose of the present study was to examine age-related changes in isokinetic leg flexion and extension peak torque (PT), PT/body weight (PT/ BW), and F*T/fat-free weight (PT/FFW) in young wrestlers. Male wrestlers (A^ = 108; age M ± SD = 11.3...

  5. Giant thermal spin-torque-assisted magnetic tunnel junction switching.

    PubMed

    Pushp, Aakash; Phung, Timothy; Rettner, Charles; Hughes, Brian P; Yang, See-Hun; Parkin, Stuart S P

    2015-05-26

    Spin-polarized charge currents induce magnetic tunnel junction (MTJ) switching by virtue of spin-transfer torque (STT). Recently, by taking advantage of the spin-dependent thermoelectric properties of magnetic materials, novel means of generating spin currents from temperature gradients, and their associated thermal-spin torques (TSTs), have been proposed, but so far these TSTs have not been large enough to influence MTJ switching. Here we demonstrate significant TSTs in MTJs by generating large temperature gradients across ultrathin MgO tunnel barriers that considerably affect the switching fields of the MTJ. We attribute the origin of the TST to an asymmetry of the tunneling conductance across the zero-bias voltage of the MTJ. Remarkably, we estimate through magneto-Seebeck voltage measurements that the charge currents that would be generated due to the temperature gradient would give rise to STT that is a thousand times too small to account for the changes in switching fields that we observe. PMID:25971730

  6. Bioprospecting for microbial products that affect ice crystal formation and growth

    Microsoft Academic Search

    Brent C. Christner

    2010-01-01

    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,

  7. Galactoglucomannan oligosaccharide Supplementation affects Nutrient Digestibility, Fermentation End-product Production, and Large Bowel Microbiota of the Dog

    Technology Transfer Automated Retrieval System (TEKTRAN)

    A galactoglucomannan oligosaccharide (GGMO) obtained from fiberboard production was evaluated as a dietary supplement for dogs. The GGMO substrate contained high concentrations of mannose, xylose, and glucose oligosaccharides. Adult dogs assigned to a 6x6 Latin square design were fed six diets, ea...

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

    Microsoft Academic Search

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

    2006-01-01

    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.

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

    ERIC Educational Resources Information Center

    Hixon, Thomas J.

    2006-01-01

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

  10. Optimum torque performance in PMSM drives above rated speed

    Microsoft Academic Search

    Alf Khre Adnanes; Tore M. Undeland

    1991-01-01

    The torque capability of a salient pole PMSM drive is theoretically analyzed. The analysis is performed with a linear, stationary, model of the motor, assuming constant voltage boundary and continuous current limitations. General steady state torque and power characteristics are presented. A new controller which ensures maximum torque to current ratio in the whole speed range is presented. Simulations and

  11. A low torque ripple PMSM drive for EPS applications

    Microsoft Academic Search

    Guang Liu; Alex Kurnia; Ronan De Larminat; Phil Desmond; T. O'Gorman

    2004-01-01

    This paper describes the practical design considerations of a low torque ripple permanent magnet synchronous motor (PMSM) drive for electric power steering (EPS) application. The impact of various controller elements on torque ripple performance is discussed in detail. The experimental results show that the low cost dc-link current sensing scheme used in the design can achieve excellent and consistent torque

  12. Torque sensorless control in multidegree-of-freedom manipulator

    Microsoft Academic Search

    Toshiyuki Murakami; Fangming Yu; Kouhei Ohnishi

    1993-01-01

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

  13. Torque ripple in a Darrieus, vertical axis wind turbine

    Microsoft Academic Search

    R. C. Reuter Jr.; R. C. Jr

    1980-01-01

    Interaction between a steady wind and a rotating, Darrieus, vertical axis wind turbine produces time periodic aerodynamic loads which cause time dependent torque variations, referred to as torque ripple, to occur in the mechanical link between the turbine and the electrical generator. There is concern for the effect of torque ripple upon fatigue life of drive train components and upon

  14. Photoexcited azo-dye induced torque in nematic liquid crystals

    Microsoft Academic Search

    B. Saad; T. V. Galstyan; M. M. Denariez-Roberge; M. Dumont

    1998-01-01

    We study molecule reorientation initiated by absorption of resonant light, in D2 azo dye doped nematic liquid crystals. The photoexcitation of the dye subsystem creates a torque on the host, that is not collinear with the traditional dielectric torque. The temporal and geometrical characteristics of these torques are also different. Transient three dimensional molecular reorientation is detected through different paths

  15. A direct torque controller for permanent magnet synchronous motor drives

    Microsoft Academic Search

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

    1999-01-01

    This paper describes an investigation of direct torque control (DTC) for permanent magnet synchronous motor (PMSM) drives. The analysis of PMSMs shows that the increase of electromagnetic torque is proportional to the increase of the angle between the stator and rotor flux linkages and therefore fast torque response can be obtained by increasing the rotating speed of the stator flux

  16. Rotary torque and rpm indicator for oil well drilling rigs

    Microsoft Academic Search

    Chien

    1981-01-01

    Monitoring the torque applied by the rotary table to the drill string and the rpm of the drill string is provided. An intermediate adapter is positioned between the drill kelly and the rotary table. A strain gauge is attached to the intermediate adapter to measure torsional deformation and provide an indication of rotary torque. Transmission of torque data is accomplished

  17. Increasing the High Speed Torque of Bipolar Stepper

    E-print Network

    Peters, Dennis

    Increasing the High Speed Torque of Bipolar Stepper Motors Introduction To successfully follow at the desired rates, and drive the load torque at the desired speeds. While the size of a bipolar stepper motor rates of the winding currents in a bipolar stepper motor pushes the motor to deliver more torque at high

  18. Quality of dissolved organic matter affects planktonic but not biofilm bacterial production in streams.

    PubMed

    Kamjunke, Norbert; Herzsprung, Peter; Neu, Thomas R

    2015-02-15

    Streams and rivers are important sites of organic carbon mineralization which is dependent on the land use within river catchments. Here we tested whether planktonic and epilithic biofilm bacteria differ in their response to the quality of dissolved organic carbon (DOC). Thus, planktonic and biofilm bacterial production was compared with patterns of DOC along a land-use gradient in the Bode catchment area (Germany). The freshness index of DOC was positively related to the proportion of agricultural area in the catchment. The humification index correlated with the proportion of forest area. Abundance and production of planktonic bacteria were lower in headwaters than at downstream sites. Planktonic production was weakly correlated to the total concentration of DOC but more strongly to quality-measures as revealed by spectra indexes, i.e. positively to the freshness index and negatively to the humification index. In contrast to planktonic bacteria, abundance and production of biofilm bacteria were independent of DOC quality. This finding may be explained by the association of biofilm bacteria with benthic algae and an extracellular matrix which represent additional substrate sources. The data show that planktonic bacteria seem to be regulated at a landscape scale controlled by land use, whereas biofilm bacteria are regulated at a biofilm matrix scale controlled by autochthonous production. Thus, the effects of catchment-scale land use changes on ecosystem processes are likely lower in small streams dominated by biofilm bacteria than in larger streams dominated by planktonic bacteria. PMID:25460970

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

    PubMed

    Abdelli, R; Rekioua, D; Rekioua, T

    2011-04-01

    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

  20. Agronomic factors affecting dryland grain sorghum maturity and production in northeast Colorado

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Grain sorghum [Sorghum bicolor (L.) Moench] is an important dryland crop in southeast Colorado, but expansion into northeast Colorado is thought to be limited due to the shorter growing season. The study examined whether sorghum production could be expanded into northeast Colorado. A 2-year study ...

  1. A survey of the factors affecting the productivity of construction projects in Iran

    Microsoft Academic Search

    Parviz Ghoddousi; Mohammad Reza Hosseini

    2012-01-01

    The intense competition between the Iranian construction companies has led them to take all appropriate measures to decrease the costs as much as possible. Hence, due to the pivotal role of human resources in construction projects cost, a major part of Iranian construction companies seek their profitability and survival in maximizing the productivity of their operatives. Because of the widespread

  2. Peat amendment and production of different crop plants affect earthworm populations in field soil

    Microsoft Academic Search

    Sanna Kukkonen; Ansa Palojärvi; Mauri Räkköläinen; Mauritz Vestberg

    2004-01-01

    A field experiment was conducted to study the effects of peat amendment and crop production system on earthworms. The experiment was established on a field previously cultivated with oats and with silt as the main soil type. Perennial crops strawberry, timothy and caraway, and annual crops rye, turnip rape, buckwheat, onion and fiddleneck were cultivated with conventional methods. All the

  3. Sunflower, soybean, and grain sorghum crop production as affected by dripline depth

    Technology Transfer Automated Retrieval System (TEKTRAN)

    A five-year field study (2004-2008) using irrigation water from an unlined surface reservoir was conducted to examine the effect of dripline depth (0.2, 0.3, 0.4, 0.5, or 0.6 m) on subsurface drip-irrigated rotational crop production of sunflower, soybean, and grain sorghum on a deep silt loam soil ...

  4. Intestinal microbial affects of yeast products on weaned and transport stressed pigs

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Study objectives were to determine effects of a commercially available yeast product (XPC, Diamond-V Mills) and stress of transportation on total Enterobacteriaceae, Escherichia coli, coliforms, and Lactobacilli populations in the intestine of weaning pigs. In a RCB design with a 2 x 2 factorial ar...

  5. COTTON PRODUCTION WITH COVER CROPS: ALDICARB AND NITROGEN AFFECT YIELD AND FIBER PROPERTIES

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Conservation tillage with cover crops is gaining wide acceptance for cotton (Gossypium hirustum L.) production, but little is known about the effects of habitat manipulation on thrips (Frankliniella sp.) populations and the effects of thrips damage on cotton yield and quality. The objectives of this...

  6. Milk production traits of beef cows as affected by horn fly numbers and breed type

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Pesticide resistance in horn flies indicates the need for more sustainable production systems. Cows sired by Bonsmara (BONS;n=7), Brangus (BRAN;n=13), Charolais (CHAR;n=8), Gelbvieh (GELV;n=5), Hereford (HERF;n=12), and Romosinuano (ROMO;n=8) from Brangus dams were used to determine breed difference...

  7. Project Summary This project is to investigate how hypoxia affects the production of specific types of

    E-print Network

    Richards-Kortum, Rebecca

    investigated hyaluronic acid turnover and production in heart valves in response to hypoxic stress. Hypoxic hypoxia as low as 0.1% oxygen tension. In investigating the hyaluronic acid response of mitral proteins: HYAL, VEGF and HIF1 . HYAL is critical in hyaluronic acid maintenance because it is responsible

  8. ACID MINE DRAINAGE AND COAL COMBUSTION PRODUCTS AFFECT CORBICULA FLUMINEA AND GAMBUSIA AFFINIS 1

    Microsoft Academic Search

    C. M. Porter; R. W. Nairn

    2004-01-01

    Toxicity tests and exposure experiments define the impacts of different metals on terrestrial and aquatic organisms. However, few examinations have evaluated the impacts of combined metals, similar to acid mine drainage (AMD), on fish and invertebrates. Toxicity associated with some selenium rich coal combustion products (CCP) has been identified, but little work has been done to identify toxicity associated with

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

    E-print Network

    Crews, Stephen

    (Andropogon gerardii, Schizachyrium scoparium, Poa pratensis, and Carex siccata) over two growing seasons 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

  10. Cultivar, harvest date, and nitrogen fertilization affect production and quality of fall oat

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Previous research has shown that oat (Avena sativa L.) has promise as a fall-forage option for dairy producers. In addition, dairy producers often have a recurring need to identify opportunity windows for manure hauling other than before or after production of corn (Zea mays L.). Our objectives were...

  11. Chronic cobalt exposure affects antioxidants and ATP production in rat myocardium.

    PubMed

    Clyne, N; Hofman-Bang, C; Haga, Y; Hatori, N; Marklund, S L; Pehrsson, S K; Wibom, R

    2001-01-01

    Chronic cobalt exposure is characterized by severe cardiac insufficiency. Since the mechanisms of cobalt toxicity are not yet clear, we analysed the effects of chronic cobalt exposure on antioxidant enzyme activities and myocardial mitochondrial ATP production rate in a rat model. One group of rats was fed a conventional diet and another a cobalt supplemented diet for 24 weeks. The manganese-superoxide dismutase activity was markedly reduced in the cobalt rats (18+/-4.7 U/mg protein) compared to the control rats (100+/-22 U/mg protein; p <0.001). Activity in the respiratory chain enzymes succinate-cytochrome c reductase, NADH-cytochrome c reductase and cytochrome c oxidase was also reduced in the cobalt rats (p<0.01). Glutamate dehydrogenase activity, located in the mitochondrial matrix, was unchanged. The mitochondrial ATP production rate in relation to myocardial mass was lower in the cobalt rats for all substrates tested except palmitoyl-l-carnitine + malate. In conclusion, 24 weeks of chronic cobalt exposure induces a marked decrease in manganese-superoxide dismutase activity, a moderate decrease in mitochondrial ATP production rate and a general reduction in the capacity of the respiratory chain. The impairment in mitochondrial ATP production might be secondary to the decreased manganese-superoxide dismutase activity, causing inactivation of mitochondrial factors susceptible to superoxide radicals. PMID:11768320

  12. Restoration of eroded landscapes to reduce variability in soil properties affecting productivity

    Technology Transfer Automated Retrieval System (TEKTRAN)

    In hilly landscapes, tillage and water erosion combine to induce large variability in soil productivity at the field scale. Approaches to manage this variability have been proposed, including restoring the landscape by physically moving soil from areas of net deposition to areas of net soil loss. We...

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

    ERIC Educational Resources Information Center

    Eagan, Mark Kevin, Jr.

    2010-01-01

    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.…

  14. Variable environment and market affects optimal nitrogen management in wheat and cattle production systems

    Technology Transfer Automated Retrieval System (TEKTRAN)

    The average efficiency of fertilizer nitrogen (N) in grain production of cereals is about 33% worldwide, and a 1% increase in fertilizer N use efficiency (NUE) could annually save US producers 200-400 million US dollars. Process-based crop simulation models provide a unique opportunity to improve f...

  15. Water use and water productivity of sugarbeet, malt barley and potato as affected by irrigation frequency

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Successful irrigation management is one of the most important agronomic practices for achieving profitable yield and maximizing crop water productivity (CWP) while maintaining environmental quality by minimizing water losses to runoff and deep drainage. This study was conducted to compare the influe...

  16. Microbiological and physicochemical factors affecting Aspergillus section Flavi incidence in Cavendish banana (Musa cavendishii) chips production in Southern Philippines.

    PubMed

    Sales, A C; Azanza, P V; Yoshizawa, T

    2005-01-01

    Microbiological and physicochemical factors affecting the incidence of Aspergillus section Flavi in dried Cavendish banana (Musa cavendishii) chips production in Southern Philippines were examined. The average counts of Aspergillus section Flavi (AFC) in fresh and dried Cavendish bananas from 10 production batches of the Philippine Agro-Industrial Development Cooperative in Davao del Norte, Southern Philippines were 1.2 x 10(2) and 1.6 x 10(2) cfu/g, respectively. Isolates from both samples were identified to be Aspergillus flavus based on spore type and conidial structure of isolates. An increasing trend in the AFC of Cavendish bananas was observed during dried banana chips processing. Variability in the AFC between production batches was attributed to differences in aerobic and fungal populations and physicochemical characteristics of the fruits, peel damage of the raw materials, concentration of AFC in the air and food-contact surfaces of the production area, and temperature and relative humidity (RH) conditions of the environment during production and storage. Physicochemical characteristics of Cavendish bananas from the receipt of raw materials up to the first day of drying were within the reported range of values allowing growth and toxin production by aflatoxigenic fungi. Air-borne AFC varied depending on the section of the production area examined. The close proximity of the waste disposal area from the production operation to the preparation, drying and storage areas suggests that cross-contamination, probably air-borne or insect-borne was a likely occurrence. The hands of workers were also identified as AFC sources. Results of this study highlight the need for the development of strategies to control aflatoxigenic fungi and aflatoxin contamination in Philippine dried Cavendish bananas. PMID:15750731

  17. Prehension Synergies during Smooth Changes of the External Torque

    PubMed Central

    Sun, Yao; Park, Jaebum; Zatsiorsky, Vladimir M.; Latash, Mark L.

    2011-01-01

    We studied characteristics of digit action and their co-variation patterns across trials (prehension synergies) during static holding of an object while the external torque could change slowly and smoothly. The subjects held in the air an instrumented handle with an attachment that allowed a smooth change in the external torque over about 12 s; the load was always kept constant. Series of trials were performed under three conditions: The torque could be zero throughout the trial or it could change slowly requiring a smooth change of the effort from a non-zero pronation value to zero (PR-0) or from a non-zero supination value to zero (SU-0). The handle was kept vertical at all times. Indices of variance and co-variation of elemental variables (forces and moments of force produced by individual digits) stabilizing such performance variables as total normal force, total tangential force, and total moment of force were computed at two levels of an assumed control hierarchy. At the upper level, the task is shared between the thumb and virtual finger (an imagined digit with the mechanical action equal to that of the four fingers), while at the lower level, action of the virtual finger is shared among the actual four fingers. We analyzed the total moment of force as the sum of the moments of force produced by the thumb and virtual finger and also as the sum of the moments of force produced by the normal forces and tangential forces. The results showed that the adjustments in the total moment of force were produced primarily with changes in the moment produced by the virtual finger and by changes in the moment produced by the normal forces. The normal force of the thumb at the final state (which was the same across conditions) was larger in the two conditions with changes in the external torque. The safety margin was significantly higher in the PR-0 condition, and it dropped with the decrease in the external torque. A co-contraction index was computed to reflect moment of force production by the fingers acting against the total moment produced by the virtual finger. It was higher for the SU-0 condition. Most variance indices dropped with a decrease in the external torque. The co-variation indices, however, remained unchanged over the trial duration. They showed signs of a trade-off between the two levels of the assumed hierarchy: Larger indices at the higher level corresponded to smaller indices at the lower level. This study and the previous one (Sun et al. 2011) document several previously unknown features of prehensile tasks. The results show that characteristics of digit action and interaction in such tasks depend not only on the magnitudes of external constraints but on a variety of other factors including time changes in the constraints and their history. PMID:21796540

  18. Torque ripple in a Darrieus, vertical axis wind turbine

    SciTech Connect

    Reuter, R.C. Jr.

    1980-01-01

    Interaction between a steady wind and a rotating, Darrieus, vertical axis wind turbine produces time periodic aerodynamic loads which cause time dependent torque variations, referred to as torque ripple, to occur in the mechanical link between the turbine and the electrical generator. There is concern for the effect of torque ripple upon fatigue life of drive train components and upon power quality. An analytical solution characterizing the phenomenon of torque ripple has been obtained which is based upon a Fourier expansion of the time dependent features of the problem. Numerical results for torque ripple, some experimental data, determination of acceptable levels and methods of controlling it, are presented and discussed.

  19. Bibliometric approach of factors affecting scientific productivity in environmental sciences and ecology.

    PubMed

    Dragos, Cristian Mihai; Dragos, Simona Laura

    2013-04-01

    Different academic bibliometric studies have measured the influence of economic, political and linguistic factors in the academic output of countries. Separate analysis in different fields can reveal specific incentive factors. Our study proves that the Environmental Performance Index, computed by Yale University, is highly significant (p<0.01) for the productivity of research and development activities in environmental sciences and ecology. The control variables like education financing, publishing of ISI Thomson domestic journals and the English language are also significant. The methodology uses Ordinary Least Squares multiple regressions with convincing results (R(2)=0.752). The relative positions of the 92 countries in the sample are also discussed. We draw up a ranking of the countries' concern for the environment, considering evenly the scientific productivity and the environment quality. We notice huge differences concerning the number of inhabitants and population income between the countries that dominate the classification and those occupying the last positions. PMID:23425795

  20. SCO5745, a bifunctional RNase J ortholog, affects antibiotic production in Streptomyces coelicolor.

    PubMed

    Bralley, Patricia; Aseem, Madiha; Jones, George H

    2014-03-01

    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

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

    PubMed Central

    Bralley, Patricia; Aseem, Madiha

    2014-01-01

    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

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

    PubMed

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

    2014-11-01

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

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

    NASA Astrophysics Data System (ADS)

    Hsiang, S. M.

    2009-12-01

    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.

  4. Cyanide exposure affects the production and excretion of ammonia by the mudskipper Boleophthalmus boddaerti

    Microsoft Academic Search

    Shit F Chew; Elaine Goh; Cheng B Lim; Yuen K Ip

    1998-01-01

    The concentrations of ammonia in the plasma of the mudskipper Boleophthalmus boddaerti exposed to cyanide for 1–6 days were significantly greater than the respective values of the controls. This was due to an increase in the production of NH3 in the muscle and an increase in the retention of NH3 and\\/or NH4+ in the blood of the cyanide-exposed fish when

  5. Bone Mineral Density of Adolescents as Affected by Calcium Intake through Milk and Milk Products

    Microsoft Academic Search

    E. Renner; M. Hermes; H. Stracke

    1998-01-01

    Elevated levels of milk and milk products were incorporated into the diet of 15–16yr old adolescents with subaverage bone mineral density in order to obtain a daily calcium intake of about 1200mg. The bone mineral density was significantly improved by about 50% when compared with control subjects without such a dietary intervention (+0.053 vs +0.036gcm-2). The rate of increase, however,

  6. Competition Affects the Production of First Backcross Offspring on F 1 -hybrids, Brassica Napus × B. Rapa

    Microsoft Academic Search

    Marina Mosbæk Johannessen; Christian Damgaard; Bente Anni Andersen; Rikke Bagger Jørgensen

    2006-01-01

    Summary  Interspecific F1-hybrids may arise in fields with transplastomic oilseed rape where B. rapa occurs as a weed. Spilled seeds, including transplastomic F1-hybrids with B. rapa, may germinate, which creates an opportunity for production of transplastomic BC1 with B. rapa as father (BC1r). Field trials were made with three different proportions of B. napus, B. rapa and F1-hybrids and three different

  7. Torque generated by the flagellar motor of Escherichia coli.

    PubMed Central

    Berg, H C; Turner, L

    1993-01-01

    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

  8. Displaceable Spur Gear Torque Controlled Driver and Method

    NASA Technical Reports Server (NTRS)

    Cook, Joseph S., Jr. (Inventor)

    1996-01-01

    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.

  9. Displaceable spur gear torque controlled driver and method

    NASA Technical Reports Server (NTRS)

    Cook, Joseph S., Jr. (inventor)

    1994-01-01

    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.

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

    PubMed

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

    2000-03-01

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

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

    NASA Technical Reports Server (NTRS)

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

    1999-01-01

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

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

    USGS Publications Warehouse

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

    2008-01-01

    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.

  13. A mutation in the aroE gene affects pigment production, virulence, and chemotaxis in Xanthomonas oryzae pv. oryzae.

    PubMed

    Kim, Hong-Il; Noh, Tae-Hwan; Lee, Chang-Soo; Park, Young-Jin

    2015-01-01

    Xanthomonas oryzae pv. oryzae (Xoo) causes bacterial blight (BB) in rice. To study its function, a random insertion mutation library of Xoo was constructed using the Tn5 transposon. A mutant strain with decreased virulence against the susceptible rice cultivar IR24 was isolated from the library (aroE mutant), which also had extremely low pigment production. Thermal asymmetric interlaced-polymerase chain reaction (TAIL-PCR) and sequence analysis of the mutant revealed that the transposon was inserted into the aroE gene (encoding shikimate dehydrogenase). To investigate gene expression changes in the pigment- and virulence-deficient mutant, DNA microarray analysis was performed, which showed downregulation of 20 genes involved in the chemotaxis of Xoo. Our findings reveal that mutation of the aroE gene affects virulence and pigment production, as well as expression of genes involved in Xoo chemotaxis. PMID:25213405

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

    NASA Technical Reports Server (NTRS)

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

    1973-01-01

    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.

  15. Swing switching of spin-torque valves

    NASA Astrophysics Data System (ADS)

    Dunn, Tom; Kamenev, Alex

    2012-11-01

    We propose a method for inducing magnetization reversal using an AC spin current polarized perpendicular to the equilibrium magnetization of the free magnetic layer. We show that the critical AC spin current is significantly smaller than the corresponding DC one. The effect is understood as a consequence of the underdamped nature of the spin-torque oscillators. It allows to use the kinetic inertia to overcome the residual energy barrier, rather than suppressing the latter by a large spin current. The effect is similar to a swing which may be set into high amplitude motion by a weak near-resonant push. The optimal AC frequency is identified as the upper bifurcation frequency of the corresponding driven nonlinear oscillator. Together with fast switching times it makes the perpendicular AC method to be the most efficient way to realize spin-torque memory valve.

  16. Six component robotic force-torque sensor

    NASA Technical Reports Server (NTRS)

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

    1987-01-01

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

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

    PubMed Central

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

    2009-01-01

    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

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

    PubMed

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

    2013-12-01

    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

  19. Body torque modulation for a microrobotic fly

    Microsoft Academic Search

    Benjamin M. Finio; Jessica K. Shang; Robert J. Wood

    2009-01-01

    The Harvard Microrobotics Lab has previously demonstrated the world's first at-scale robotic insect capable of vertical takeoff with external power. Both of the robot's wings were driven by a single power actuator and 1-DOF mechanical transmission-making independent control of both wings, and therefore asymmetric flapping and the generation of a net body torque, impossible. This paper presents a method to

  20. Monitoring in torque-summed electromechanical actuators

    Microsoft Academic Search

    Fawaz Annaz

    2008-01-01

    The main aim of this paper is to address cross-monitoring techniques (lumped and hardware) in a single-type torque-summed architecture. In the lumped cross-monitoring technique, all lanes will be represented by their lumped models, while in hardware cross-monitoring, three-phase equivalents will model each motor. The analysis is based on a 4-lane actuation system capable of driving aerodynamic and inertial loads (with

  1. Monitoring in smart torque-summed actuators

    Microsoft Academic Search

    Fawaz Y. Annaz

    2009-01-01

    This paper addresses fault detection and fault isolation in single-type torque-summed architecture. The analysis is based around a 4-lane actuation system capable of driving aerodynamic and inertial loads (with 2 lanes failed) of an aileron control surface similar to that of the Sea Harrier. The paper describes the lanes and the dedicated embed microprocessor\\/s that performs the control and monitoring

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

    PubMed

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

    2014-07-01

    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

  3. Development of an ankle torque measurement device for measuring ankle torque during walking

    PubMed Central

    Tanino, Genichi; Tomita, Yutaka; Mizuno, Shiho; Maeda, Hirofumi; Miyasaka, Hiroyuki; Orand, Abbas; Takeda, Kotaro; Sonoda, Shigeru

    2015-01-01

    [Purpose] To develop a device for measuring the torque of an ankle joint during walking in order to quantify the characteristics of spasticity of the ankle and to verify the functionality of the device by testing it on the gait of an able-bodied individual and an equinovarus patient. [Subjects and Methods] An adjustable posterior strut (APS) ankle-foot orthosis (AFO) was used in which two torque sensors were mounted on the aluminum strut for measuring the anterior-posterior (AP) and medial-lateral (ML) directions. Two switches were also mounted at the heel and toe in order to detect the gait phase. An able-bodied individual and a left hemiplegic patient with equinovarus participated. They wore the device and walked on a treadmill to investigate the device’s functionality. [Results] Linear relationships between the torques and the corresponding output of the torque sensors were observed. Upon the analyses of gait of an able-body subject and a hemiplegic patient, we observed toque matrices in both AP and ML directions during the gait of the both subjects. [Conclusion] We developed a device capable of measuring the torque in the AP and ML directions of ankle joints during gait.

  4. Development of an ankle torque measurement device for measuring ankle torque during walking.

    PubMed

    Tanino, Genichi; Tomita, Yutaka; Mizuno, Shiho; Maeda, Hirofumi; Miyasaka, Hiroyuki; Orand, Abbas; Takeda, Kotaro; Sonoda, Shigeru

    2015-05-01

    [Purpose] To develop a device for measuring the torque of an ankle joint during walking in order to quantify the characteristics of spasticity of the ankle and to verify the functionality of the device by testing it on the gait of an able-bodied individual and an equinovarus patient. [Subjects and Methods] An adjustable posterior strut (APS) ankle-foot orthosis (AFO) was used in which two torque sensors were mounted on the aluminum strut for measuring the anterior-posterior (AP) and medial-lateral (ML) directions. Two switches were also mounted at the heel and toe in order to detect the gait phase. An able-bodied individual and a left hemiplegic patient with equinovarus participated. They wore the device and walked on a treadmill to investigate the device's functionality. [Results] Linear relationships between the torques and the corresponding output of the torque sensors were observed. Upon the analyses of gait of an able-body subject and a hemiplegic patient, we observed toque matrices in both AP and ML directions during the gait of the both subjects. [Conclusion] We developed a device capable of measuring the torque in the AP and ML directions of ankle joints during gait. PMID:26157244

  5. Dietary inclusion of diallyl disulfide, yucca powder, calcium fumarate, an extruded linseed product, or medium-chain fatty acids does not affect methane production in lactating dairy cows.

    PubMed

    van Zijderveld, S M; Dijkstra, J; Perdok, H B; Newbold, J R; Gerrits, W J J

    2011-06-01

    Two similar experiments were conducted to assess the effect of diallyl disulfide (DADS), yucca powder (YP), calcium fumarate (CAFU), an extruded linseed product (UNSAT), or a mixture of capric and caprylic acid (MCFA) on methane production, energy balance, and dairy cow performance. In experiment 1, a control diet (CON1) and diets supplemented with 56 mg of DADS/kg of dry matter (DM), 3g of YP/kg of DM, or 25 g of CAFU/kg of DM were evaluated. In experiment 2, an inert saturated fat source in the control diet (CON2) was exchanged isolipidically for an extruded linseed source (100g/kg of DM; UNSAT) or a mixture of C8:0 and C10:0 (MCFA; 20.3g/kg of DM). In experiment 2, a higher inclusion level of DADS (200mg/kg of DM) was also tested. Both experiments were conducted using 40 lactating Holstein-Friesian dairy cows. Cows were adapted to the diet for 12 d and were subsequently kept in respiration chambers for 5 d to evaluate methane production, diet digestibility, energy balance, and animal performance. Feed intake was restricted to avoid confounding effects of possible differences in ad libitum feed intake on methane production. Feed intake was, on average, 17.5 and 16.6 kg of DM/d in experiments 1 and 2, respectively. None of the additives reduced methane production in vivo. Methane production in experiment 1 was 450, 453, 446, and 423 g/d for CON1 and the diets supplemented with DADS, YP, and CAFU, respectively. In experiment 2, methane production was 371, 394, 388, and 386 g/d for CON2 and the diets supplemented with UNSAT, MCFA, and DADS, respectively. No effects of the additives on energy balance or neutral detergent fiber digestibility were observed. The addition of MCFA increased milk fat content (5.38% vs. 4.82% for control) and fat digestibility (78.5% vs. 59.8% for control), but did not affect milk yield or other milk components. The other products did not affect milk yield or composition. Results from these experiments emphasize the need to confirm methane reductions observed in vitro with in vivo data. PMID:21605778

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

    PubMed

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

    2012-12-01

    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

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

    PubMed

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

    2014-08-01

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

  8. A differential electromagnetic induction torque sensor and its finite element analysis.

    PubMed

    Hao, Zhao

    2015-05-01

    Torque is an important parameter for condition monitoring and fault diagnosis for rotary machines. This paper describes a new structure differential torque sensor based on the principle of electromagnetic induction. The method involves the construction of a pulsating flux by the excitation winding of the sensor, and the torsion angle produced by the load torque is converted into the angle displacements of the excitation winding and the output winding. Last, the output winding of sensor generates an induction potential force, which is proportional to the load torque as seen through electromagnetic coupling. Sensor sensitivity would be reduced by load effect; therefore, this paper presents a suppression method that can ensure the sensitivity is not affected. The transfer function of the sensor is constructed through Laplace transformation. The sensor characteristics are simulated by finite elements, including the influence of winding coil numbers and excitation voltage frequency. The sensor was calibrated by a torsion testing machine, and the experimental results indicated that the sensitivity of the sensor is about 18.2 mV/Nm, the non-repeatability error is about 2.3%, the non-linear error is about 3.3%, and the hysteresis error is about 2.6%. PMID:26026550

  9. A differential electromagnetic induction torque sensor and its finite element analysis

    NASA Astrophysics Data System (ADS)

    Hao, Zhao

    2015-05-01

    Torque is an important parameter for condition monitoring and fault diagnosis for rotary machines. This paper describes a new structure differential torque sensor based on the principle of electromagnetic induction. The method involves the construction of a pulsating flux by the excitation winding of the sensor, and the torsion angle produced by the load torque is converted into the angle displacements of the excitation winding and the output winding. Last, the output winding of sensor generates an induction potential force, which is proportional to the load torque as seen through electromagnetic coupling. Sensor sensitivity would be reduced by load effect; therefore, this paper presents a suppression method that can ensure the sensitivity is not affected. The transfer function of the sensor is constructed through Laplace transformation. The sensor characteristics are simulated by finite elements, including the influence of winding coil numbers and excitation voltage frequency. The sensor was calibrated by a torsion testing machine, and the experimental results indicated that the sensitivity of the sensor is about 18.2 mV/Nm, the non-repeatability error is about 2.3%, the non-linear error is about 3.3%, and the hysteresis error is about 2.6%.

  10. Factors affecting production of mold mycelium and protein in synthetic media.

    PubMed Central

    Graham, D C; Steinkraus, K H; Hackler, L R

    1976-01-01

    The effects of certain cultural conditions on the yield of dry mycelium, protein, and total amino acid content of Rhizopus oligosporus Saito (NRRL 2710), Rhizopus rhizopodiformis (Cohn apud Lichtheim) Zopf (NRRL 6246), and Absidia corymbifera (Cohn) Sacc. et Trotter (NRRL 6247) were studied. The yield of mycelium was found to significantly increase as the spore inoculum was increased from 187,500 to 2,250,000 spores. But the total amino acids (grams/liter) did not change significantly, whereas the percentage of crude protein decreased. An inoculum containing approximately 750,000 spores/ml was used in all of the other experiments. Mycelial production was highest at 37 degrees C for all three molds. However, the best temperature for percentage of crude protein and total amino acids varied with the organism. The mycelial yield and total crude protein of R. oligosporus showed some significant changes as the C/N ratio was increased in 3% glucose medium. In a synthetic medium having a 15:1 C/N ratio, the strains of R. oligosporus, R. rhizopodiformis, and A. corymbifera had better yields from falactose than glucose, not only in dry mycelium but also in total crude protein (grams/liter) and total amino acids (grams/liter). R. oligosporus grew very well on several ammonium salts. but the maximum yield of dry mycelium, total crude protein (grams/liter), and total amino acids (grams/liter) occurred with ammonium sulfate. The optimum pH for both Rhizopus species was 4.0, although R. oligosporus grew equally well at pH 3.0 and slightly less at pH 5.0. The highest yield of mycelium for A. corymbifera was obtained in a medium with an initial pH of 8.0. It was calculated that a fermenter chanrged with an adequate medium and 1,000 lb (about 450 kg) of R. oligosporus or A. corymbifera cells could produce 88 or 90 lb of protein (on a dry-weight basis) per h if the product was removed continuously. PMID:10836

  11. Bevel gear driver and method having torque limit selection

    NASA Technical Reports Server (NTRS)

    Cook, Joseph S., Jr. (inventor)

    1994-01-01

    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.

  12. The sps Gene Products Affect the Germination, Hydrophobicity, and Protein Adsorption of Bacillus subtilis Spores

    PubMed Central

    Cangiano, Giuseppina; Sirec, Teja; Panarella, Cristina; Isticato, Rachele; Baccigalupi, Loredana; De Felice, Maurilio

    2014-01-01

    The multilayered surface of the Bacillus subtilis spore is composed of proteins and glycans. While over 70 different proteins have been identified as surface components, carbohydrates associated with the spore surface have not been characterized in detail yet. Bioinformatic data suggest that the 11 products of the sps operon are involved in the synthesis of polysaccharides present on the spore surface, but an experimental validation is available only for the four distal genes of the operon. Here, we report a transcriptional analysis of the sps operon and a functional study performed by constructing and analyzing two null mutants lacking either all or only the promoter-proximal gene of the operon. Our results show that both sps mutant spores apparently have normal coat and crust but have a small germination defect and are more hydrophobic than wild-type spores. We also show that spores lacking all Sps proteins are highly adhesive and form extensive clumps. In addition, sps mutant spores have an increased efficiency in adsorbing a heterologous enzyme, suggesting that hydrophobic force is a major determinant of spore adsorption and indicating that a deep understanding of the surface properties of the spore is essential for its full development as a surface display platform. PMID:25239894

  13. Bevel Gear Driver and Method Having Torque Limit Selection

    NASA Technical Reports Server (NTRS)

    Cook, Joseph S., Jr. (Inventor)

    1997-01-01

    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.

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

    PubMed

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

    2014-03-01

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

  15. Electronic measurement of variable torques in precision work technology

    NASA Technical Reports Server (NTRS)

    Maehr, M.

    1978-01-01

    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.

  16. Torque–speed relationship of the bacterial flagellar motor

    PubMed Central

    Xing, Jianhua; Bai, Fan; Berry, Richard; Oster, George

    2006-01-01

    Many swimming bacteria are propelled by flagellar filaments driven by a rotary motor. Each of these tiny motors can generate an impressive torque. The motor torque vs. speed relationship is considered one of the most important measurable characteristics of the motor and therefore is a major criterion for judging models proposed for the working mechanism. Here we give an explicit explanation for this torque–speed curve. The same physics also can explain certain puzzling properties of other motors. PMID:16432218

  17. Defining the mechanisms by which the reactive oxygen species by-product, 4-hydroxynonenal, affects human sperm cell function.

    PubMed

    Baker, Mark A; Weinberg, Anita; Hetherington, Louise; Villaverde, Ana-Izabel; Velkov, Tony; Baell, Jonathan; Gordon, Christopher P

    2015-04-01

    Lipid peroxidation products such as the naturally occurring aldehyde 4-hydroxynonenal (4-HNE) are known to be cytotoxic toward different cell types, including spermatozoa. In order to understand this at the molecular level, we have employed a proteomic approach to characterize direct 4-HNE adducts on human spermatozoa. Several proteins were identified to be of particular interest, including aldehyde labeling of histone methyltransferase and dynein heavy chain. In addition, we found that 4-HNE bound to part of the activation segment, cysteine residue 199, of protein kinase A (PKA). Interestingly, at low levels, addition of 4-HNE had a stimulatory effect on PKA. However, this did not correlate to increased phosphotyrosine levels during capacitation. This data explains the link between reactive oxygen species and sperm toxicity. Given that epigenetic regulation is likely affected in oxidative-stressed spermatozoa, this data show that spermatozoa appear to shut down under these conditions before reaching the egg. PMID:25673561

  18. Remote sensing for assessing the zone of benefit where deep drains improve productivity of land affected by shallow saline groundwater.

    PubMed

    Kobryn, H T; Lantzke, R; Bell, R; Admiraal, R

    2015-03-01

    The installation of deep drains is an engineering approach to remediate land salinised by the influence of shallow groundwater. It is a costly treatment and its economic viability is, in part, dependent on the lateral extent to which the drain increases biological productivity by lowering water tables and soil salinity (referred to as the drains' zone of benefit). Such zones may be determined by assessing the biological productivity response of adjacent vegetation over time. We tested a multi-temporal satellite remote sensing method to analyse temporal and spatial changes in vegetation condition surrounding deep drainage sites at five locations in the Western Australian wheatbelt affected by dryland salinity-Morawa, Pithara, Beacon, Narembeen and Dumbleyung. Vegetation condition as a surrogate for biological productivity was assessed by Normalised Difference Vegetation Index (NDVI) during the peak growing season. Analysis was at the site scale within a 1000 m buffer zone from the drains. There was clear evidence of NDVI increasing with elevation, slope and distance from the drain. After accounting for elevation, slope and distance from the drain, there was a significant increase in NDVI across the five locations after installation of deep drains. Changes in NDVI after drainage were broadly consistent with measured changes at each site in groundwater levels after installation of the deep drains. However, this study assessed the lateral extent of benefit for biological productivity and gave a measure of the area of benefit along the entire length of the drain. The method demonstrated the utility of spring NDVI images for rapid and relatively simple assessment of the change in site condition after implementation of drainage, but approaches for further improvement of the procedure were identified. PMID:25481499

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

    PubMed

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

    2014-01-01

    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 B? (AFB?), B? (AFB?), G? (AFG?) and G? (AFG?) 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, AFB? 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 B? 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, AFG? and AFG? 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

  20. Description of current-driven torques in magnetic tunnel junctions

    NASA Astrophysics Data System (ADS)

    Manchon, A.; Ryzhanova, N.; Vedyayev, A.; Chschiev, M.; Dieny, B.

    2008-04-01

    A free electron description of spin-dependent transport in magnetic tunnel junctions with non-collinear magnetizations is presented. We investigate the origin of transverse spin density in tunneling transport and the quantum interferences which give rise to oscillatory torques on the local magnetization. Spin transfer torque is also analyzed and an important bias asymmetry is found as well as a damped oscillatory behavior. Furthermore, we investigate the influence of the s-d exchange coupling on torque, in particular in the case of half-metallic MTJs, in which the spin transfer torque is due to interfacial spin-dependent reflections.

  1. Torque ripple minimization in switched reluctance motors using adaptive fuzzy control

    Microsoft Academic Search

    Sayeed Mir; Malik Elbuluk; Iqbal Husain

    1997-01-01

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

  2. A linear maximum torque per ampere control for IPMSM drives over full-speed range

    Microsoft Academic Search

    Ching-Tsai Pan; Shinn-Ming Sue

    2005-01-01

    In this paper, a linear torque control strategy is first proposed for interior permanent magnet synchronous motor drives to fully utilize the reluctance torque and simplify the controller design. The proposed linear torque control strategy also extends the existing maximum torque per ampere control in the constant torque limit region up to the entire field-weakening region. It is found that

  3. A torque magnetometer for thin films applications

    NASA Astrophysics Data System (ADS)

    Rigue, J.; Chrischon, D.; de Andrade, A. M. H.; Carara, M.

    2012-04-01

    We describe the development of an automatic torque magnetometer based on a torsion pendulum. The instrument uses the capacitive arrange developed by Randall D. Peters, Rev. Sci. Instr. 60 (8), 2789 (1989), as sample's angular position sensor. The instrument performance is illustrated by measuring the in plane magnetic anisotropy of Co thin films and systems with exchange-bias. It possesses a sensitivity of 10?10 Nm and is capable to determine anisotropy constants in magnetic films as thin as 3 nm. The instrument design and the measurement procedures are presented.

  4. Torque generation by the flagellar rotary motor.

    PubMed Central

    Berg, H C

    1995-01-01

    A review is given of the structure and dynamics of the flagellar rotary motor. Force-generating elements in a motor driving a tethered bacterium (a cell fixed to the substratum by a single flagellum) exert forces of order 20 pN while moving at speeds of order 1 micron/s. Force-generating elements in a motor driving a flagellar filament in a bundle exert forces some 10-fold lower but move at speeds more than 10-fold higher. The motor torque-speed relationship has been measured over a wide dynamic range. Motors strongly resist being driven backwards and are easily broken. PMID:7787060

  5. Evidence of sustained populations of a small reef fish on artificial structures. Does depth affect production on artificial reefs?

    PubMed

    Fowler, A M; Booth, D J

    2012-03-01

    The length frequencies and age structures of resident Pseudanthias rubrizonatus (n = 407), a small protogynous serranid, were measured at four isolated artificial structures on the continental shelf of north-western Australia between June and August 2008, to determine whether these structures supported full (complete size and age-structured) populations of this species. The artificial structures were located in depths between 82 and 135 m, and growth rates of juveniles and adults, and body condition of adults, were compared among structures to determine the effect of depth on potential production. All life-history stages, including recently settled juveniles, females and terminal males, of P. rubrizonatus were caught, ranging in standard length (L(s)) from 16·9 to 96·5 mm. Presumed ages estimated from whole and sectioned otoliths ranged between 22 days and 5 years, and parameter ±s.e. estimates of the von Bertalanffy growth model were L(?) = 152 ± 34 mm, k = 0·15(±0·05) and t(0) = -1·15(±0·15). Estimated annual growth rates were similar between shallow and deep artificial structures; however, otolith lengths and recent growth of juveniles differed among individual structures, irrespective of depth. The artificial structures therefore sustained full populations of P. rubrizonatus, from recently settled juveniles through to adults; however, confirmation of the maximum age attainable for the species is required from natural populations. Depth placement of artificial reefs may not affect the production of fish species with naturally wide depth ranges. PMID:22380556

  6. Low-Intensity Pulsed Ultrasound Affects Chondrocyte Extracellular Matrix Production via an Integrin-Mediated p38 MAPK Signaling Pathway.

    PubMed

    Xia, Peng; Ren, Shasha; Lin, Qiang; Cheng, Kai; Shen, Shihao; Gao, Mingxia; Li, Xueping

    2015-06-01

    Although low-intensity pulsed ultrasound (LIPUS) regulates p38 mitogen-activated protein kinase (MAPK) and promotes cartilage repair in osteoarthritis, the role of integrin-mediated p38 MAPK in the effect of LIPUS on extracellular matrix (ECM) production of normal and OA chondrocytes remains unknown. The aim of this study was to investigate whether LIPUS affects ECM production in normal and OA rabbit chondrocytes through an integrin-p38 signaling pathway. A rabbit model of OA was established by anterior cruciate ligament transection, and chondrocytes were isolated from normal or OA cartilage and cultured in vitro. Chondrocytes were treated with LIPUS and then pre-incubated with the integrin inhibitor GRGDSP or the p38 inhibitor SB203580. Expression of type II collagen, MMP-13, integrin ?1, p38 and phosphorylated p38 was assessed by Western blot analysis. We found that type II collagen and integrin ?1 were upregulated (p < 0.05), whereas MMP-13 was downregulated (p < 0.05) in normal and OA chondrocytes. Furthermore, phosphorylated p38 was upregulated (p < 0.05) in normal chondrocytes, but downregulated (p < 0.05) in OA chondrocytes after LIPUS stimulation. Pre-incubation of chondrocytes with the integrin inhibitor disrupted the effects of LIPUS on normal and OA chondrocytes. Pre-incubation of chrondocytes with the p38 inhibitor reduced the effects of LIPUS on normal chondrocytes, but had no impact on OA chondrocytes. Our findings suggest that the integrin-p38 MAPK signaling pathway plays an important role in LIPUS-mediated ECM production in chondrocytes. PMID:25736607

  7. Spin-orbit torques in magnetic bilayers

    NASA Astrophysics Data System (ADS)

    Haney, Paul

    2015-03-01

    Spintronics aims to utilize the coupling between charge transport and magnetic dynamics to develop improved and novel memory and logic devices. Future progress in spintronics may be enabled by exploiting the spin-orbit coupling present at the interface between thin film ferromagnets and heavy metals. In these systems, applying an in-plane electrical current can induce magnetic dynamics in single domain ferromagnets, or can induce rapid motion of domain wall magnetic textures. There are multiple effects responsible for these dynamics. They include spin-orbit torques and a chiral exchange interaction (the Dzyaloshinskii-Moriya interaction) in the ferromagnet. Both effects arise from the combination of ferromagnetism and spin-orbit coupling present at the interface. There is additionally a torque from the spin current flux impinging on the ferromagnet, arising from the spin hall effect in the heavy metal. Using a combination of approaches, from drift-diffusion to Boltzmann transport to first principles methods, we explore the relative contributions to the dynamics from these different effects. We additionally propose that the transverse spin current is locally enhanced over its bulk value in the vicinity of an interface which is oriented normal to the charge current direction.

  8. Electromagnetic force and torque in ponderable media.

    PubMed

    Mansuripur, Masud

    2008-09-15

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

  9. Nonambipolarity, orthogonal conductivity, poloidal flow, and torque

    SciTech Connect

    Hulbert, G.W.; Perkins, F.W.

    1989-02-01

    Nonambipolar processes, such as neutral injection onto trapped orbits or ripple-diffusion loss of ..cap alpha..-particles, act to charge a plasma. A current j/sub r/ across magnetic surfaces must arise in the bulk plasma to maintain charge neutrality. An axisymmetric, neoclassical model of the bulk plasma shows that these currents are carried by the ions and exert a j/sub r/B/sub theta/R/c torque in the toroidal direction. A driven poloidal flow V/sub theta/ = E/sub r/'c/B must also develop. The average current density is related to the radial electric field E/sub r/' = E/sub r/ + v/sub /phi//B/sub theta//c in a frame moving with the plasma via the orthogonal conductivity = sigma/sub /perpendicular//E/sub r/', which has the value sigma/sub /perpendicular// = (1.65epsilon/sup 1/2/)(ne/sup 2/..nu../sub ii//M..cap omega../sub theta//sup 2/) in the banana regime. If an ignited plasma loses an appreciable fraction ..delta.. of its thermonuclear ..cap alpha..-particles by banana ripple diffusion, then the torque will spin the plasma to sonic rotation in a time /tau//sub s/ approx. 2/tau//sub E//..delta.., /tau//sub E/ being the energy confinement time. 10 refs., 1 fig.

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

    NASA Technical Reports Server (NTRS)

    Aldridge, Hal A.; Juang, Jer-Nan

    1997-01-01

    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.

  11. Torque prediction using the flux-MMF diagram in AC, DC, and reluctance motors

    Microsoft Academic Search

    David A. Staton; Rajesh P. Deodhar; Wen L. Soong; Timothy J. E. Miller

    1996-01-01

    This paper uses the flux-MMF diagram to compare and contrast the torque production mechanism in seven common types of electric motor. The flux-MMF diagram is a generalized version of the flux-linkage versus current (?-i) diagram for switched-reluctance motors. It is illustrated for switched-reluctance, synchronous-reluctance, induction, brushless AC, brushless DC, interior PM and commutator motors. The calculated flux-MMF diagrams for motors

  12. On torque ripple reduction in current-fed switched reluctance motors

    Microsoft Academic Search

    A. M. Stankovic; G. Tadmor; Z. J. Coric; I. Agirman

    1999-01-01

    This paper addresses a basic control issue in switched reluctance motor (SRM) drives-the production of a ripple-free torque. Simple and largely model-independent conventional supply waveforms are not able to satisfy this requirement. The goal of this paper is to improve SRM dynamical performance by compensating for motor nonlinearities, while maintaining the robustness of conventional methods. The method is based on

  13. Variation tolerant sensing scheme of Spin-Transfer Torque Memory for yield improvement

    Microsoft Academic Search

    Zhenyu Sun; Hai Li; Yiran Chen; Xiaobin Wang

    2010-01-01

    Spin-Transfer Torque Random Access Memory (STT-RAM) demonstrated great potentials as an universal memory for its fast access speed, zero standby power, excellent scalability and simplicity of cell structure. However, large process variations of both magnetic tunneling junction and CMOS process severely limit the yield of STT-RAM chips and prevent the massive production from happening. In this paper, we analyze the

  14. A Systems Approach to the Torque Control of a Permanent Magnet Brushless Motor

    E-print Network

    Paul, Benjamin J.

    1987-08-01

    Many approaches to force control have assumed the ability to command torques accurately. Concurrently, much research has been devoted to developing accurate torque actuation schemes. Often, torque sensors have been ...

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

    PubMed

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

    2012-04-01

    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

  16. Van der Waals torque induced by external magnetic fields

    NASA Astrophysics Data System (ADS)

    Esquivel-Sirvent, R.; Cocoletzi, G. H.; Palomino-Ovando, M.

    2010-12-01

    We present a method for inducing and controlling van der Waals torques between two parallel slabs using a constant magnetic field. The torque is calculated using the Barash theory of dispersive torques. In III-IV semiconductors such as InSb, the effect of an external magnetic field is to induce an optical anisotropy, in an otherwise isotropic material, that will in turn induce a torque. The calculations of the torque are done in the Voigt configuration, with the magnetic field parallel to the surface of the slabs. As a case study we consider a slab made of calcite and a second slab made of InSb. In the absence of magnetic field there is no torque. As the magnetic field increases, the optical anisotropy of InSb increases and the torque becomes different from zero, increasing with the magnetic field. The resulting torque is of the same order of magnitude as that calculated using permanent anisotropic materials when the magnetic fields is close to 1 T.

  17. On Attitude Stabilization of Symmetric Spacecraft with Two Control Torques

    E-print Network

    Tsiotras, Panagiotis

    On Attitude Stabilization of Symmetric Spacecraft with Two Control Torques Panagiotis Tsiotras. However, feedback control laws can be derived for a restricted problem corresponding to attitude stabi] the problem of attitude stabilization of a symmet- ric spacecraft is treated, using control torques supplied

  18. Designing Well Paths To Reduce Drag and Torque

    Microsoft Academic Search

    M. C. Sheppard; C. Wick; T. Burgess

    1987-01-01

    A deviated well with an undersection trajectory (i.e., a trajectory lying below the conventional tangent section and constantly building to target) can exhibit lower drag and torque than a conventional well geometry in certain circumstances. The influence of well geometry on drag and torque is discussed, making use of the results of the theoretical model. Although an undersection well may

  19. Torque meter aids study of hysteresis motor rings

    NASA Technical Reports Server (NTRS)

    Cole, M.

    1967-01-01

    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.

  20. Direct shaft torque measurements in a transient turbine facility

    Microsoft Academic Search

    Paul F. Beard; Thomas Povey

    2011-01-01

    This paper describes the development and implementation of a shaft torque measurement system for the Oxford Turbine Research Facility (formerly the Turbine Test Facility (TTF) at QinetiQ, Farnborough), or OTRF. As part of the recent EU TATEF II programme, the facility was upgraded to allow turbine efficiency measurements to be performed. A shaft torque measurement system was developed as part

  1. 14 CFR 29.397 - Limit pilot forces and torques.

    Code of Federal Regulations, 2011 CFR

    2011-01-01

    ...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)...

  2. 14 CFR 29.397 - Limit pilot forces and torques.

    Code of Federal Regulations, 2012 CFR

    2012-01-01

    ...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)...

  3. 14 CFR 29.397 - Limit pilot forces and torques.

    Code of Federal Regulations, 2013 CFR

    2013-01-01

    ...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)...

  4. 14 CFR 29.397 - Limit pilot forces and torques.

    Code of Federal Regulations, 2014 CFR

    2014-01-01

    ...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)...

  5. 14 CFR 27.397 - Limit pilot forces and torques.

    Code of Federal Regulations, 2012 CFR

    2012-01-01

    ...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)...

  6. 14 CFR 27.397 - Limit pilot forces and torques.

    Code of Federal Regulations, 2013 CFR

    2013-01-01

    ...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)...

  7. 14 CFR 27.397 - Limit pilot forces and torques.

    Code of Federal Regulations, 2011 CFR

    2011-01-01

    ...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)...

  8. 14 CFR 29.397 - Limit pilot forces and torques.

    Code of Federal Regulations, 2010 CFR

    2010-01-01

    ...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)...

  9. 14 CFR 27.397 - Limit pilot forces and torques.

    Code of Federal Regulations, 2010 CFR

    2010-01-01

    ...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)...

  10. 14 CFR 27.397 - Limit pilot forces and torques.

    Code of Federal Regulations, 2014 CFR

    2014-01-01

    ...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)...

  11. Minimization of Torque Ripple in Brushless DC Motor Drives

    Microsoft Academic Search

    Hoang Le-Huy; Robert Perret; Rene Feuillet

    1986-01-01

    Torque characteristics of brushless dc motors are studied in terms of the EMF and the feed currents for two feeding schemes: two-phase feeding and three-phase feeding. Various techniques for minimizing torque ripple are considered and discussed. For three-phase feeding systems, a selective harmonics elimination technique is studied and its effectiveness is evaluated.

  12. Sensorless torque estimation using adaptive Kalman filter and disturbance estimator

    Microsoft Academic Search

    Sang-Chul Lee; Hyo-Sung Ahn

    2010-01-01

    This paper presents a stochastic estimation method and a signal processing based method for estimating disturbance torques without using any force sensors. The first method will address a robustness against measurement noises by estimating noise covariance. The second method will show several practical merits. By containing system models inside of the estimator, the total disturbance torque injected into the plant

  13. Damping torque estimation and oscillatory stability margin prediction

    Microsoft Academic Search

    Hassan Ghasemi; Claudio Canizares

    2006-01-01

    The damping torque of linearized models of power systems is studied here as a possible on-line security index, based on system identification techniques applied to realistic measurements. First, the theoretical values of damping and synchronizing coefficients of the electromagnetic torque are discussed in detail. These values are then used to investigate the accuracy of damping coefficient identified from on-line measurements

  14. Direct torque control of induction machines using space vector modulation

    Microsoft Academic Search

    T. G. Habetler; F. Profumo; M. Pastorelli; L. M. Tolbert

    1991-01-01

    A control scheme for direct torque and flux control of induction machines based on the stator flux field orientation method is proposed. With the proposed predictive control scheme, an inverter duty cycle is directly based on the torque and flux errors, the transient reactance of the machine, and an estimated value of the voltage behind the transient reactance. A method

  15. Atypical Brain Torque in Boys With Developmental Stuttering

    Microsoft Academic Search

    Jeffrey Ryan Mock; Janet N. Zadina; David M. Corey; Jeremy D. Cohen; Lisa C. Lemen; Anne L. Foundas

    2012-01-01

    The counterclockwise brain torque, defined as a larger right prefrontal and left parietal-occipital lobe, is a consistent brain asymmetry. Reduced or reversed lobar asymmetries are markers of atypical cerebral laterality and have been found in adults who stutter. It was hypothesized that atypical brain torque would be more common in children who stutter. Magnetic resonance imaging-based morphology measures were completed

  16. Haptic Rendering Algorithm for Biomolecular Docking with Torque Force

    Microsoft Academic Search

    Xiyuan Hou; Olga Sourina

    2010-01-01

    Haptic devices enable the user to manipulate the molecules and feel interactions during the docking process in virtual environment on the computer. Implementation of torque feedback allows the user to have more realistic experience during force simulation and find the optimum docking positions faster. In this paper, we propose a haptic rendering algorithm for biomolecular docking with torque force. It

  17. Development of a biped robot with torque controlled joints

    Microsoft Academic Search

    Christian Ott; C. Baumgartner; J. Mayr; M. Fuchs; R. Burger; Dongheui Lee; O. Eiberger; A. Albu-Schaffer; M. Grebenstein; G. Hirzinger

    2010-01-01

    This paper gives an overview of the development of a novel biped walking machine. The robot is designed as an experimental system for studying biped locomotion based on torque controlled joints. As an underlying drive technology, the torque controlled joint units of the DLR-KUKA-Lightweight-Robot are employed. The relevant design choices for using this technology in a biped robot with integrated

  18. Study on Improved Maximum-Torque Slip Frequency Control

    Microsoft Academic Search

    Du Guiping; Zhang Weilin

    2010-01-01

    This paper introduces the main control methods of AC motor. Using traditional slip frequency control method, the PI parameters are hard to be determined, digitization of the current-slip curve is hard to be realized and the maximum torque cannot be obtained. A maximum-torque slip frequency control method is proposed to meet the requirements of mining locomotives. Simulation and experiment shows

  19. Optical torque on small bi-isotropic particles.

    PubMed

    Nieto-Vesperinas, Manuel

    2015-07-01

    We establish the equations for the time-averaged optical torque on dipolar bi-isotropic particles. Due to the interference of the scattered fields, it has a term additional to the one that is commonly employed in theory and experiments. Its consequences for conservation of energy, angular momentum, and effects like negative torques are discussed. PMID:26125357

  20. Torque vectors of neck muscles in the cat

    Microsoft Academic Search

    C. R. Wickland; J. F. Baker; B. W. Peterson

    1991-01-01

    Anatomical texts describe the neck musculature without measurements of muscle locations or quantitative estimates of pulling actions (torques). This study is based on measurements in stereotaxic coordinates of cat neck muscle origins and insertions, and neck intervertebral rotation axes. Torque vectors in three dimensions were calculated for 14 pairs of dorsal and ventral muscles that insert on the skull or

  1. Spin Torque and Zeta Force of Dimer of Alkali Atoms

    Microsoft Academic Search

    Masato Senami; Jun Nishikawa; Takaaki Hara; Akitomo Tachibana

    2010-01-01

    In this work, the novel theoretical approach to predict the torque for spin is studied. This approach is based on the novel quantities, the spin torque and the zeta force, which are proposed by one of the authors. These quantities govern the dynamics of the spin of electrons, and hence, can clarify the essential description of the dynamics of the

  2. NEW DEVELOPMENT OF TORQUE ANALYSIS OF SYNCHRONOUS MACHINE

    Microsoft Academic Search

    WANG. XIANGHENG; K. L. LO

    1997-01-01

    By using a multi-loop model, a new technique for analysing the torque of a synchronous machine is presented in this paper. The electro-magnetic torque of the machine which is very difficult to calculate in some operation conditions by other methods, can be obtained from the inductances of the machine and the currents of every loop of the machine, then the

  3. Torque and drag characteristics of a six bladed savonius rotor

    Microsoft Academic Search

    Shamsun Nahar; Mohammad Ali

    2012-01-01

    The research work has been carried out to study the aerodynamic characteristic i.e., drag coefficient torque coefficient etc. of a vertical axis type six bladed Savonius rotor. At first drag and torque characteristics of the six bladed Savonius rotor are determined by measuring the pressure distribution over the convex and concave surfaces of each blade at different angle of rotation.

  4. Spin-transfer-torque effect in ferromagnets and antiferromagnets

    NASA Astrophysics Data System (ADS)

    Wei, Zhen

    Spintronics in metallic multilayers, composed of ferromagnetic (F) and non-magnetic (N) metals, grew out of two complementary discoveries. The first, Giant Magneto-resistance (GMR), refers to a change in multilayer resistance when the relative orientation of magnetic moments in adjacent F-layers is altered by an applied magnetic field. The second, Spin-Transfer-Torque (STT), involves a change in the relative orientation of F-layer moments by an electrical current. This novel physical phenomenon offers unprecedented spatial and temporal control over the magnetic state of a ferromagnet and has tremendous potential in a broad range of technologies, including magnetic memory and recording. Because of its small size (<10nm), point contact is a very efficient probe of electrical transport properties in extremely small sample volumes yet inaccessible with other techniques. We have observed the point-contact excitations in magnetic multilayers at room temperature and extended the capabilities of our point-contact technique to include the sensitivity to wavelengths of the current-induced spin waves. Recently MacDonald and coworkers have predicted that similar to ferromagnetic multilayers, the magnetic state of an antiferromagnetic (AFM) system can affect its transport properties and result in antiferromagnetic analogue of giant magnetoresistance (GMR) = AGMR; while high enough electrical current density can affect the magnetic state of the system via spin-transfer-torque effect. We show that a high density dc current injected from a point contact into an exchange-biased spin valve (EBSV) can systematically change the exchange bias, increasing or decreasing it depending on the current direction. This is the first evidence for current-induced effects on magnetic moments in antiferromagnetic (FeMn or IrMn) metals. We searched for AGMR in multilayers containing different combinations of AFM=FeMn and F=CoFe layers. At low currents, no magnetoresistance (MR) was observed in any samples suggesting that no AGMR is present in these samples. In samples containing F-layers, high current densities sometimes produced a small positive MR -- largest resistance at high fields. For a given contact resistance, this MR was usually larger for thicker F-layers, and for a given current, it was usually larger for larger contact resistances (smaller contacts). We tentatively attribute this positive MR to suppression at high currents of spin accumulation induced around and within the F-layers.

  5. Torque Expressions and Equivalent Circuits for Salient Pole Synchronous Machines

    NASA Astrophysics Data System (ADS)

    Kondo, Minoru

    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.

  6. Electromagnetic Torques, Precession and Evolution of Magnetic Inclination of Pulsars

    E-print Network

    Zanazzi, J J

    2015-01-01

    We present analytic calculations of the electromagnetic torques acting on a magnetic neutron star rotating in vacuum, including near-zone torques associated with the inertia of dipole and quadrupole magnetic fields. We incorporate these torques into the rotational dynamics of a rigid-body neutron star, and show that the effects of the inertial torque can be understood as a modification of the moment of inertia tensor of the star. We apply our rotational dynamics equation to the Crab pulsar, including intrinsic distortions of the star and various electromagnetic torques, to investigate the possibility that the counter-alignment of the magnetic inclination angle, as suggested by recent observations, could be explained by pulsar precession. We find that if the effective principal axis of the pulsar is nearly aligned with either the magnetic dipole axis or the rotation axis, then precession may account for the observed counter-alignment over decade timescales. Over the spindown timescale of the pulsar, the magnet...

  7. Torque: topology-free querying of protein interaction networks

    PubMed Central

    Bruckner, Sharon; Hüffner, Falk; Karp, Richard M.; Shamir, Ron; Sharan, Roded

    2009-01-01

    Torque is a tool for cross-species querying of protein–protein interaction networks. It aims to answer the following question: given a set of proteins constituting a known complex or a pathway in one species, can a similar complex or pathway be found in the protein network of another species? To this end, Torque seeks a matching set of proteins that are sequence similar to the query proteins and span a connected region of the target network, while allowing for both insertions and deletions. Unlike existing approaches, Torque does not require knowledge of the interconnections among the query proteins. It can handle large queries of up to 25 proteins. The Torque web server is freely available for use at http://www.cs.tau.ac.il/?bnet/torque.html. PMID:19491310

  8. Torque Sensor Based on Tunnel-Diode Oscillator

    NASA Technical Reports Server (NTRS)

    Chui, Talso; Young, Joseph

    2008-01-01

    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.

  9. Overexpression of the Insulin-Like Growth Factor II Receptor Increases ?-Amyloid Production and Affects Cell Viability.

    PubMed

    Wang, Y; Buggia-Prévot, V; Zavorka, M E; Bleackley, R C; MacDonald, R G; Thinakaran, G; Kar, S

    2015-07-15

    Amyloid ? (A?) peptides originating from amyloid precursor protein (APP) in the endosomal-lysosomal compartments play a critical role in the development of Alzheimer's disease (AD), the most common type of senile dementia affecting the elderly. Since insulin-like growth factor II (IGF-II) receptors facilitate the delivery of nascent lysosomal enzymes from the trans-Golgi network to endosomes, we evaluated their role in APP metabolism and cell viability using mouse fibroblast MS cells deficient in the murine IGF-II receptor and corresponding MS9II cells overexpressing the human IGF-II receptors. Our results show that IGF-II receptor overexpression increases the protein levels of APP. This is accompanied by an increase of ?-site APP-cleaving enzyme 1 levels and an increase of ?- and ?-secretase enzyme activities, leading to enhanced A? production. At the cellular level, IGF-II receptor overexpression causes localization of APP in perinuclear tubular structures, an increase of lipid raft components, and increased lipid raft partitioning of APP. Finally, MS9II cells are more susceptible to staurosporine-induced cytotoxicity, which can be attenuated by ?-secretase inhibitor. Together, these results highlight the potential contribution of IGF-II receptor to AD pathology not only by regulating expression/processing of APP but also by its role in cellular vulnerability. PMID:25939386

  10. Environmental Factors Affecting Production, Release, and Field Populations of Conidia of Alternaria alternata, the Cause of Brown Spot of Citrus.

    PubMed

    Timmer, L W; Solel, Z; Gottwald, T R; Ibañez, A M; Zitko, S E

    1998-11-01

    ABSTRACT Alternaria brown spot, caused by Alternaria alternata pv. citri, affects many tangerines and their hybrids, causing loss of immature leaves and fruit and reducing the marketability of the remaining fruit. Conidial production of A. alternata was greatest on mature leaves moistened and maintained at near 100% relative humidity (RH) for 24 h, whereas leaves that had been soaked or maintained at moderate RH produced few conidia. Conidial release from filter paper cultures and infected leaves was studied in a computer-controlled environmental chamber. Release of large numbers of conidia was triggered from both substrates by sudden drops in RH or by simulated rainfall events. Vibration induced release of low numbers of conidia, but red/infrared irradiation had no effect. In field studies from 1994 to 1996, air sampling with a 7-day recording volumetric spore trap indicated that conidia were present throughout the year with periodic large peaks. The number of conidia captured was not closely related to rainfall amounts or average wind speed, but was weakly related to the duration of leaf wetness. Likewise, disease severity on trap plants placed in the field weekly during 1995 to 1996 was not closely related to conidial numbers or rainfall amounts, but was weakly related to leaf wetness duration. Sufficient inoculum appears to be available to allow infection to occur throughout the year whenever susceptible host tissue and moisture are available. PMID:18944857

  11. Alternating bending-steady torque fatigue reliability

    NASA Technical Reports Server (NTRS)

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

    1974-01-01

    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.

  12. Spin supercurrents and torquing with Majorana fermions

    NASA Astrophysics Data System (ADS)

    Shtengel, Kirill; Kovalev, Alexey; de, Amrit

    2014-03-01

    We show that resonant coupling and entanglement between a mechanical resonator and majorana bound states can be achieved via spin supercurrents in a 1D quantum wire with strong spin-orbit interactions in the proximity of s-wave superconductor. The bound states induced by vibrating and stationary magnets can hybridize thus resulting in spin-current induced 4 ? -periodic torque, as a function of the relative field angle, acting on the resonator. We propose a realization based on spin transistor like architecture in which a heterostructure nanowire consists of semiconductors with large and small g-factors in order to form the topological and non-topological regions. We also study the feasibility of detecting and manipulating majorana bound states with the use of magnetic resonance force microscopy techniques. U.S. Army Research Office under Grant No. W911NF-11-1-0027, NSF under Grant No. 1018935, DARPA-QuEST program, NSF under Grant DMR-0748925.

  13. A Tail Not to Get "Torqued" About

    NASA Technical Reports Server (NTRS)

    1999-01-01

    NASA has licensed technology to a Washington state company for improving the performance, stability and control of helicopters. Under the agreement, Boundary Layer Research, Inc., Everett, Wash., will commercially market an aerodynamic device called "tailboom strakes." The license will allow the company to market the NASA-patented device to civil and military operators of single rotor helicopters. For the past year Boundary Layer Research has been working with NASA Langley Research Center, Hampton, Va., to explore the viability of helicopter strake technology developed by a NASA-Army team of researchers. The technology is applicable to all single rotor helicopters and is patented by NASA as a "Low Speed Anti-Torque System." The company has applied for Federal Aviation Administration certification to make the technology available to civil operators and owners.

  14. IEEE TRANSACTIONS ON INDUSTRIAL ELECTRONICS, VOL. 46, NO. 1, FEBRUARY 1999 177 On Torque Ripple Reduction in Current-Fed

    E-print Network

    Stankoviæ, Aleksandar

    Reduction in Current-Fed Switched Reluctance Motors Aleksandar M. Stankovi´c, Member, IEEE, Gilead Tadmor issue in switched reluctance motor (SRM) drives--the production of a ripple-free torque. Simple verifying the analytical approach are included. Index Terms-- Nonlinear systems, reluctance motor drives

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

    Microsoft Academic Search

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

    2003-01-01

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

  16. Hydrodynamic modeling of pseudorapidity flow correlations in relativistic heavy-ion collisions and the torque effect

    NASA Astrophysics Data System (ADS)

    Bo?ek, Piotr; Broniowski, Wojciech; Olszewski, Adam

    2015-05-01

    We analyze correlations between the event-plane angles in different intervals of pseudorapidity within the 3+1-dimensional viscous hydrodynamics with the Glauber-model initial conditions. As predicted earlier, the fluctuations in the particle production mechanism in the earliest stage, together with asymmetry of the emission profiles in pseudorapidity from the forward and backwardgoing wounded nucleons, lead to the torque effect, namely, decorrelation of the event-plane angles in distant pseudorapidity bins. We use two- or three-bin measures of correlation functions to quantify the effect, with the latter compared to the recent data from the CMS collaboration. We find a sizable torque effect, with magnitude larger at the BNL Relativistic Heavy Ion Collider than at the CERN Large Hadron Collider.

  17. Hydrodynamic modeling of pseudorapidity flow correlations in relativistic heavy-ion collisions and the torque effect

    E-print Network

    Piotr Bozek; Wojciech Broniowski; Adam Olszewski

    2015-03-25

    We analyze correlations between the event-plane angles in different intervals of pseudorapidity within the 3+1-dimensional viscous hydrodynamics with the Glauber-model initial conditions. As predicted earlier, the fluctuations in the particle production mechanism in the earliest stage, together with asymmetry of the emission profiles in pseudorapidity from the forward- and backward going wounded nucleons, lead to the torque effect, namely, decorrelation of the event-plane angles in distant pseudorapidity bins. We use two- or three-bin measures of correlation functions to quantify the effect, with the latter compared to the recent data from the CMS collaboration. We find a sizable torque effect, with magnitude larger at RHIC than at the LHC.

  18. Hydrodynamic modeling of pseudorapidity flow correlations in relativistic heavy-ion collisions and the torque effect

    E-print Network

    Bozek, Piotr; Olszewski, Adam

    2015-01-01

    We analyze correlations between the event-plane angles in different intervals of pseudorapidity within the 3+1-dimensional viscous hydrodynamics with the Glauber-model initial conditions. As predicted earlier, the fluctuations in the particle production mechanism in the earliest stage, together with asymmetry of the emission profiles in pseudorapidity from the forward- and backward going wounded nucleons, lead to the torque effect, namely, decorrelation of the event-plane angles in distant pseudorapidity bins. We use two- or three-bin measures of correlation functions to quantify the effect, with the latter compared to the recent data from the CMS collaboration. We find a sizable torque effect, with magnitude larger at RHIC than at the LHC.

  19. Torque during canal instrumentation using rotary nickel-titanium files.

    PubMed

    Sattapan, B; Palamara, J E; Messer, H H

    2000-03-01

    Nickel-titanium engine-driven rotary instruments are used increasingly in endodontic practice. One frequently mentioned problem is fracture of an instrument in the root canal. Very few studies have been conducted on torsional characteristics of these instruments, and none has been done under dynamic conditions. The purposes of this study were to measure the torque generated and the apical force applied during instrumentation with a commercial engine-driven nickel-titanium file system, and to relate torque generated during simulated clinical use to torsional failure of the instruments. Ten extracted human teeth (five with small-sized and five with medium-sized straight root canals) were instrumented with Quantec Series 2000 files, and the torque and apical force generated were measured. The applied apical force was generally low, not exceeding 150 g in either small or medium canals. The torque depended on the tip size and taper of each instrument, and on canal size. Instruments with 0.05 and 0.06 taper generated the highest torque, which was greater in small than in medium canals. The torque at failure was significantly (p < 0.001) higher than torque during instrumentation, but with considerable variation in the extent of the difference. PMID:11199710

  20. Algorithm for calculating torque base in vehicle traction control system

    NASA Astrophysics Data System (ADS)

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

    2012-11-01

    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.

  1. Lunar and Solar Torques on the Oceanic Tides

    NASA Technical Reports Server (NTRS)

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

    1998-01-01

    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.

  2. Relationship between navicular drop and measuring position of maximal plantar flexion torque of the first and second-fifth metatarsophalangeal joints

    PubMed Central

    Saeki, Junya; Tojima, Michio; Torii, Suguru

    2015-01-01

    [Purpose] The purpose of this study was to determine the relationship between navicular drop and plantar flexion torque of the first and second-fifth metatarsophalangeal joints. [Subjects] Ten healthy young men participated in this study. [Methods] The Pearson product-moment correlation coefficient was calculated to determine the relationship between navicular drop and plantar flexion torque of the first and second-fifth metatarsophalangeal joints. [Results] Significant negative correlations were observed between navicular drop and plantar flexion torques in the lengthened position of the intrinsic toe plantar flexion muscles, but no correlations were found between navicular drop and plantar flexion torques in the neutral position of the ankle and metatarsophalangeal joints. Moreover, the intrinsic toe plantar flexion muscles were found to contribute to the formation of the medial longitudinal arch. [Conclusion] Navicular drop correlates with metatarsophalangeal joint muscle strength in plantar flexion where the intrinsic toe muscles are capable of exerting force. PMID:26180323

  3. High torque DC motor fabrication and test program

    NASA Technical Reports Server (NTRS)

    Makus, P.

    1976-01-01

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

  4. Interactions between torque and helical buckling in drilling

    SciTech Connect

    He, X.; Halsey, G.W.; Kyllingstad, A.

    1995-12-31

    The effects of torque on helical buckling are a concern in coiled tubing drilling. These effects are also important in conventional drilling of long horizontal wells. This paper presents theoretical models for the effects of torque on helical buckling, normal contact force, and pitch of helix in the curved well bore. The effects of helical buckling and the post-buckling contact forces on torque and drag in a drilling operation are also modelled. The models are used for realistic simulations for both conventional drilling and coiled tubing applications.

  5. A flight simulator control system using electric torque motors

    NASA Technical Reports Server (NTRS)

    Musick, R. O.; Wagner, C. A.

    1975-01-01

    Control systems are required in flight simulators to provide representative stick and rudder pedal characteristics. A system has been developed that uses electric dc torque motors instead of the more common hydraulic actuators. The torque motor system overcomes certain disadvantages of hydraulic systems, such as high cost, high power consumption, noise, oil leaks, and safety problems. A description of the torque motor system is presented, including both electrical and mechanical design as well as performance characteristics. The system develops forces sufficiently high for most simulations, and is physically small and light enough to be used in most motion-base cockpits.

  6. Advanced Glycation End-Products Reduce Collagen Molecular Sliding to Affect Collagen Fibril Damage Mechanisms but Not Stiffness

    PubMed Central

    Fessel, Gion; Li, Yufei; Diederich, Vincent; Guizar-Sicairos, Manuel; Schneider, Philipp; Sell, David R.; Monnier, Vincent M.; Snedeker, Jess G.

    2014-01-01

    Advanced glycation end-products (AGE) contribute to age-related connective tissue damage and functional deficit. The documented association between AGE formation on collagens and the correlated progressive stiffening of tissues has widely been presumed causative, despite the lack of mechanistic understanding. The present study investigates precisely how AGEs affect mechanical function of the collagen fibril – the supramolecular functional load-bearing unit within most tissues. We employed synchrotron small-angle X-ray scattering (SAXS) and carefully controlled mechanical testing after introducing AGEs in explants of rat-tail tendon using the metabolite methylglyoxal (MGO). Mass spectrometry and collagen fluorescence verified substantial formation of AGEs by the treatment. Associated mechanical changes of the tissue (increased stiffness and failure strength, decreased stress relaxation) were consistent with reports from the literature. SAXS analysis revealed clear changes in molecular deformation within MGO treated fibrils. Underlying the associated increase in tissue strength, we infer from the data that MGO modified collagen fibrils supported higher loads to failure by maintaining an intact quarter-staggered conformation to nearly twice the level of fibril strain in controls. This apparent increase in fibril failure resistance was characterized by reduced side-by-side sliding of collagen molecules within fibrils, reflecting lateral molecular interconnectivity by AGEs. Surprisingly, no change in maximum fibril modulus (2.5 GPa) accompanied the changes in fibril failure behavior, strongly contradicting the widespread assumption that tissue stiffening in ageing and diabetes is directly related to AGE increased fibril stiffness. We conclude that AGEs can alter physiologically relevant failure behavior of collagen fibrils, but that tissue level changes in stiffness likely occur at higher levels of tissue architecture. PMID:25364829

  7. Torque ripple suppression control for PM motor with current control based on PTC

    Microsoft Academic Search

    Kento Nakamura; Hiroshi Fujimoto; Masami Fujitsuna

    2010-01-01

    PM motor drive systems are widely used for industrial drives. However, PM motors basically produce the torque ripple due to the fluctuation of the magnetic field distribution. Dead time of the inverter, offset of sensors and current measurement errors lead to the torque ripple, too. The torque ripple leads vibration noises. In this paper, we proposed a torque ripple suppression

  8. A new switched reluctance motor drive circuit for torque ripple reduction

    Microsoft Academic Search

    Hiroki Ishikawa; Daohong Wang; Haruo Naitoh

    2002-01-01

    This paper presents a new switched reluctance motor (SRM) drive circuit for torque ripple reduction. The main drawbacks of SRMs are large torque ripple and acoustic noise. The torque ripple can be reduced by the stator current waveform shaping. This paper gives ideal stator current waveforms for the flat instantaneous torque. The new SRM drive circuit is proposed to synthesize

  9. Hydraulic control system for lock-up clutch of torque converter

    Microsoft Academic Search

    Ideta

    1986-01-01

    A hydraulic control system is described for an automatic transmission of an automotive vehicle having an engine, comprising: a pump driven by the engine to discharge hydraulic fluid; a torque converter including a torque converter cavity, an impeller, and a turbine which are disposed in the torque converter cavity, the torque converter including a lock-up clutch which has a lock-up

  10. The Use of Small Voltage Vectors of Matrix Converters in Direct Torque Control of Induction Machines

    Microsoft Academic Search

    Carlos Ortega; Antoni Arias; Josep Ballcells; Cedric Caruanat; Cyril Spiterit; Joseph Ciliat

    2006-01-01

    The effects on torque performance when using small voltage vectors of Matrix Converters is investigated in this paper. These vectors are used in order to reduce the electromagnetic torque ripple which appears when Direct Torque Control technique is used in Induction Motors. Direct Torque Control for Induction Motors using Matrix Converters is reviewed and it is pointed out the problem

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

    Microsoft Academic Search

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

    2007-01-01

    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

  12. Estimates of the dissipative heat and axial torque generated by ocean tides on icy satellites in the outer solar system.

    NASA Astrophysics Data System (ADS)

    Tyler, R.

    2012-09-01

    The tidal flow response generated in a satellite ocean depends strongly on the ocean configuration parameters as these parameters control the form and frequencies of the ocean's natural modes of oscillation; if there is a near match between the form and frequency of one of these natural modes and that of one of the available tidal forcing constituents, the ocean can be resonantly excited, producing a strong tidal response. The fundamental elements of the response are described by the tidal flow and surface fluctuations. Derivative elements of the response include the associated dissipative heat, stress, and forces/torques. The dissipative heat has received much previous attention as it may be important in explaining the heat budget on several of the satellites in the Outer Solar System. While these estimates will be reviewed and compared with the tidal dissipation estimates compiled in Hussman et al. (2010), the primary goal in this presentation is to extend the analysis to consider the tidally generated axial torque on the satellites and the potential consquences for rotation. Interestingly, even a synchronously rotating satellite will, if a global fluid layer is included, experience a complex set of opportunities for torques in both the prograde and retrograde sense. The amplitude and sense of the torque sensitively depends on the ocean parameters controlling the tidal response. This sensitivity, combined with expected feedbacks whereby the tides affect the orbital parameters, suggests that the evolution of the satellite system will experience phases of both prograde and retrograde tidal torques during its evolution. A related point is that parameters of the ocean might be inferred from inferences or observations of torque or rotational deviations. In the panels to the right we show the nondimensional tidal torques associated with obliquity (top) and eccentricity (bottom). The parameters described in the labeling are the fluid density ?, surface gravity g, ocean surface area A, tidal equilibrium height ?F, dissipation quality factor Q,and c=(gh)1/2, cr=?a, with ocean thickness h, rotation rate ?, and radius a. Torque due to tides forced by obliquity as a function of the parameters c/cr and Q. Retrograde ("Westward") and prograde ("Eastward") components shown in left and right panels, respectively. Log10 scale shown in colorbar.

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

    PubMed

    Pigeon, Pascale; Dizio, Paul; Lackner, James R

    2013-09-01

    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

  14. A Sensorless Direct Torque Control Scheme Suitable for Electric Vehicles

    E-print Network

    Paris-Sud XI, Université de

    the vehicle dynamics. Simulations were first carried out on a test vehicle propelled by a 37-kW induction, direct torque control, vehicle dynamics. I. INTRODUCTION Recently a lot of effort was focused

  15. Chiral spin torque arising from proximity-induced magnetization

    NASA Astrophysics Data System (ADS)

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

    2014-05-01

    Domain walls can be driven by current at very high speeds in nanowires formed from ultra-thin, perpendicularly magnetized cobalt layers and cobalt/nickel multilayers deposited on platinum underlayers due to a chiral spin torque. An important feature of this torque is a magnetic chiral exchange field that each domain wall senses and that can be measured by the applied magnetic field amplitude along the nanowire where the domain walls stop moving irrespective of the magnitude of the current. Here we show that this torque is manifested when the magnetic layer is interfaced with metals that display a large proximity-induced magnetization, including iridium, palladium and platinum but not gold. A correlation between the strength of the chiral spin torque and the proximity-induced magnetic moment is demonstrated by interface engineering using atomically thin dusting layers. High domain velocities are found where there are large proximity-induced magnetizations in the interfaced metal layers.

  16. Intraband and interband spin-orbit torques in noncentrosymmetric ferromagnets

    NASA Astrophysics Data System (ADS)

    Li, Hang; Gao, H.; Zârbo, Liviu P.; Výborný, K.; Wang, Xuhui; Garate, Ion; Doǧan, Fatih; ?ejchan, A.; Sinova, Jairo; Jungwirth, T.; Manchon, Aurélien

    2015-04-01

    Intraband and interband contributions to the current-driven spin-orbit torque in magnetic materials lacking inversion symmetry are theoretically studied using the Kubo formula. In addition to the current-driven fieldlike torque TFL=?FLm ×uso (uso being a unit vector determined by the symmetry of the spin-orbit coupling), we explore the intrinsic contribution arising from impurity-independent interband transitions and producing an anti-damping-like torque of the form TDL=?DLm ×(uso×m ) . Analytical expressions are obtained in the model case of a magnetic Rashba two-dimensional electron gas, while numerical calculations have been performed on a dilute magnetic semiconductor (Ga,Mn)As modeled by the Kohn-Luttinger Hamiltonian exchange coupled to the Mn moments. Parametric dependencies of the different torque components and similarities to the analytical results of the Rashba two-dimensional electron gas in the weak disorder limit are described.

  17. Torque and Schizophrenic Vulnerability: As the World Turns

    ERIC Educational Resources Information Center

    Blau, Theodore H.

    1977-01-01

    Based upon reports of parents and guardians, with subjects at an average age of 21 years, it was found that 11 of the youngsters who had exhibited torque had in the interim been diagnosed as schizophrenic. (Author)

  18. `Pugnatron'-like reaction in a patient with familial dystonia: torque induced motion analysis

    PubMed Central

    Walsh, E. Geoffrey

    1974-01-01

    A patient is described who suffered from an unusual extrapyramidal syndrome involving both legs and one arm. In the affected parts there was an extreme degree of rigidity. Measurements have been made of the motion that occurred as a result of applying force to the left foot. The torque was provided by a printed motor. The effect of a maintained plantar flexing force was anomalous for the foot moved to a dorsiflexed position. A model illustrating possible principles of feedback control—the Pugnatron—is described. Images PMID:4836750

  19. Dzyaloshinskii-Moriya domain wall resonance in ferromagnetic nanowires with a spin-transfer torque

    NASA Astrophysics Data System (ADS)

    Li, Zai-Dong; Liu, Fei; Li, Qiu-Yan; He, P. B.

    2015-05-01

    We theoretically investigate the current-induced domain wall resonance in ferromagnetic nanowires with a Dzyaloshinskii-Moriya interaction. The adiabatic and nonadiabatic torques distort the wall's internal structure and exert a global pressure on the wall. An effective Newton's equation is obtained analytically for a domain wall moving in one-dimensional potential and subject to a viscous friction and a driving force. Our results demonstrate that the Dzyaloshinskii-Moriya interaction affects the critical current density for depinning the wall, resonance frequency, and amplitude.

  20. Negative Thrust and Torque Characteristics of an Adjustable-Pitch Metal Propeller

    NASA Technical Reports Server (NTRS)

    Hartman, Edwin P

    1934-01-01

    This report presents the results of a series of negative thrust and torque measurements made with a 4 foot diameter model of a conventional aluminum-alloy propeller. The tests were made in the 20-foot propeller-research tunnel of the National Advisory Committee for Aeronautics. The results show that the negative thrust is considerably affected by the shape and size of the body behind the propeller, that the maximum negative thrust increases with decrease in blade-angle setting, and that the drag of a locked propeller may be greatly reduced by feathering it into the wind. Several examples of possible applications of the data are given.

  1. Controlling Magnetization using Spin Orbit Torque

    NASA Astrophysics Data System (ADS)

    Salahuddin, Sayeef

    2015-03-01

    Recently it has been shown that spin orbit coupling (SOC) and/or broken inversion symmetry in vertical heterostructures can generate accumulation of spins when a charge current is flowing through them. In doing so, it can exert a torque on an adjacent magnet. Indeed, high Z metals (Ta, Pt, W, etc.) with strong SOC have been used to inject spin currents into adjacent ferromagnetic layers and thereby to induce magnetic switching, oscillation, domain wall movement etc. SOC physics promises to significantly reduce the required current for current induced magnetic switching for next generation data-storage applications. In this presentation we shall discuss some of our recent work on SOC induced control of magnets with perpendicular magnetic anisotropy (PMA). A current flowing in-plane presents interesting symmetry problems with respect to a PMA magnet. We shall discuss how these symmetry relations can be utilized for switching of and domain wall movement in the PMA magnets. In addition to storage applications, we shall also discuss possibility of exploiting SOC for spintronic logic applications.

  2. Spintronic Memristor Through Spin-Torque-Induced Magnetization Motion

    Microsoft Academic Search

    Xiaobin Wang; Yiran Chen; Haiwen Xi; Hai Li; Dimitar Dimitrov

    2009-01-01

    Existence of spintronic memristor in nanoscale is demonstrated based upon spin-torque-induced magnetization switching and magnetic-domain-wall motion. Our examples show that memristive effects are quite universal for spin-torque spintronic device at the time scale that explicitly involves the interactions between magnetization dynamics and electronic charge transport. We also proved that the spintronic device can be designed to explore and memorize the

  3. Direct shaft torque measurements in a transient turbine facility

    NASA Astrophysics Data System (ADS)

    Beard, Paul F.; Povey, Thomas

    2011-03-01

    This paper describes the development and implementation of a shaft torque measurement system for the Oxford Turbine Research Facility (formerly the Turbine Test Facility (TTF) at QinetiQ, Farnborough), or OTRF. As part of the recent EU TATEF II programme, the facility was upgraded to allow turbine efficiency measurements to be performed. A shaft torque measurement system was developed as part of this upgrade. The system is unique in that, to the authors' knowledge, it provided the first direct measurement of shaft torque in a transient turbine facility although the system has wider applicability to rotating test facilities in which power measurement is a requirement. The adopted approach removes the requirement to quantify bearing friction, which can be difficult to accurately calibrate under representative operating conditions. The OTRF is a short duration (approximately 0.4 s run time) isentropic light-piston facility capable of matching all of the non-dimensional parameters important for aerodynamic and heat studies, namely Mach number, Reynolds number, non-dimensional speed, stage pressure ratio and gas-to-wall temperature ratio. The single-stage MT1 turbine used for this study is a highly loaded unshrouded design, and as such is relevant to modern military, or future civil aero-engine design. Shaft torque was measured directly using a custom-built strain gauge-based torque measurement system in the rotating frame of reference. This paper describes the development of this measurement system. The system was calibrated, including the effects of temperature, to a traceable primary standard using a purpose-built facility. The bias and precision uncertainties of the measured torque were ±0.117% and ±0.183%, respectively. To accurately determine the shaft torque developed by a turbine in the OTRF, small corrections due to inertial torque (associated with changes in the rotational speed) and aerodynamic drag (windage) are required. The methods for performing these corrections are described.

  4. Torque magnetometry on thin magnetite films at low temperatures

    Microsoft Academic Search

    R. Höhne; C. A Kleint; A. V. Pan; M. K Krause; M. Ziese; P. Esquinazi

    2000-01-01

    Torque magnetometry was used to investigate the magnetic anisotropy of epitaxial Fe3O4 films of thicknesses 420 and 40nm grown by pulsed laser deposition on (001) MgO substrates. Torque measurements at 130K in the (11?0) plane allow us to evaluate the influence of shape and stress anisotropy. As in bulk material field-cooled measurements performed at T=5K show that the magnetic anisotropy

  5. Torques without Rotation: the Right-Angle Lever

    E-print Network

    Shapiro, Joel A

    2012-01-01

    An extended body subject to external forces which exert zero net force and zero total torque in the rest frame, may experience a nonzero torque in another inertial frame, and nonetheless does not rotate. Long known as the Trouton-Noble or right-angle lever paradox, there has been extensive discussion and indeed controversy, but a clear understanding comes from a suitable treatment of angular momentum and simultaneity.

  6. Torques without Rotation: the Right-Angle Lever

    E-print Network

    Joel A. Shapiro

    2012-06-20

    An extended body subject to external forces which exert zero net force and zero total torque in the rest frame, may experience a nonzero torque in another inertial frame, and nonetheless does not rotate. Long known as the Trouton-Noble or right-angle lever paradox, there has been extensive discussion and indeed controversy, but a clear understanding comes from a suitable treatment of angular momentum and simultaneity.

  7. Torqued fireballs in relativistic heavy-ion collisions

    SciTech Connect

    Bozek, Piotr [H. Niewodniczanski Institute of Nuclear Physics, Polish Academy of Sciences, PL-31342 Krakow (Poland); Institute of Physics, Rzeszow University, PL-35959 Rzeszow (Poland); Broniowski, Wojciech [H. Niewodniczanski Institute of Nuclear Physics, Polish Academy of Sciences, PL-31342 Krakow (Poland); Institute of Physics, Jan Kochanowski University, PL-25406 Kielce (Poland); Moreira, Joao [Centro de Fisica Computacional, Department of Physics, University of Coimbra, P-3004-516 Coimbra (Portugal)

    2011-03-15

    We show that the fluctuations in the wounded-nucleon model of the initial stage of relativistic heavy-ion collisions, together with the natural assumption that the forward- (backward-) moving wounded nucleons emit particles preferably in the forward (backward) direction, lead to an event-by-event torqued fireball. The principal axes associated with the transverse shape are rotated in the forward region in the opposite direction than in the backward region. On the average, the standard deviation of the relative torque angle between the forward and backward rapidity regions is {approx}20 deg. for the central and 10 deg. for the midperipheral collisions. The hydrodynamic expansion of a torqued fireball leads to a torqued collective flow, yielding, in turn, torqued principal axes of the transverse-momentum distributions at different rapidities. We propose experimental measures, based on cumulants involving particles in different rapidity regions, which should allow for a quantitative determination of the effect from the data. To estimate the nonflow contributions from resonance decays we run Monte Carlo simulations with therminator, a thermal heavy-ion generator. If the event-by-event torque effect is found in the data, it will support the assumptions concerning the fluctuations in the early stage of the fireball formation, as well as the hypothesis of the asymmetric rapidity shape of the emission functions of the moving sources in the nucleus-nucleus collisions.

  8. Mechanics of torque generation in the bacterial flagellar motor

    E-print Network

    Kranthi K. Mandadapu; Jasmine A. Nirody; Richard M. Berry; George Oster

    2015-01-13

    The bacterial flagellar motor (BFM) is responsible for driving bacterial locomotion and chemotaxis, fundamental processes in pathogenesis and biofilm formation. In the BFM, torque is generated at the interface between transmembrane proteins (stators) and a rotor. It is well-established that the passage of ions down a transmembrane gradient through the stator complex provides the energy needed for torque generation. However, the physics involved in this energy conversion remain poorly understood. Here we propose a mechanically specific model for torque generation in the BFM. In particular, we identify two fundamental forces involved in torque generation: electrostatic and steric. We propose that electrostatic forces serve to position the stator, while steric forces comprise the actual 'power stroke'. Specifically, we predict that ion-induced conformational changes about a proline 'hinge' residue in an $\\alpha$-helix of the stator are directly responsible for generating the power stroke. Our model predictions fit well with recent experiments on a single-stator motor. Furthermore, we propose several experiments to elucidate the torque-speed relationship in motors where the number of stators may not be constant. The proposed model provides a mechanical explanation for several fundamental features of the flagellar motor, including: torque-speed and speed-ion motive force relationships, backstepping, variation in step sizes, and the puzzle of swarming experiments.

  9. A Lyapunov Function-Based Robust Direct Torque Controller for a Switched Reluctance Motor Drive System

    Microsoft Academic Search

    Sanjib Kumar Sahoo; Souvik Dasgupta; Sanjib Kumar Panda; Jian-Xin Xu

    2012-01-01

    A novel Lyapunov function-based direct torque controller for minimization of torque ripples in a switched reluctance motor (SRM) drive system is reported in this paper. SRM magnetization characteristics are highly nonlinear, where torque is a complex and coupled function of the phase currents and rotor position. The direct torque control (DTC) scheme avoids the complex process of torque-to-current conversion as

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

    SciTech Connect

    Hsu, J.S.

    2004-09-30

    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.

  11. Ankle and hip postural strategies defined by joint torques

    NASA Technical Reports Server (NTRS)

    Runge, C. F.; Shupert, C. L.; Horak, F. B.; Zajac, F. E.; Peterson, B. W. (Principal Investigator)

    1999-01-01

    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.

  12. How do price-based sales affect market basket prices? Evidence for fresh food products in German grocery stores

    Microsoft Academic Search

    Jens-Peter Loy; Robert D. Weaver

    2006-01-01

    Sales of fresh food products are a predominant feature in retail pricing around the world. Price-based sales offer significant price cuts in products for a limited time and are the most popular form of promotional sales in Europe. From a consumer perspective, it is of interest to determine whether such price-based sales are reflected in the price of typical market

  13. Lexical Activation in Bilinguals' Speech Production Is Dynamic: How Language Ambiguous Words Can Affect Cross-Language Activation

    ERIC Educational Resources Information Center

    Hermans, Daan; Ormel, E.; van Besselaar, Ria; van Hell, Janet

    2011-01-01

    Is the bilingual language production system a dynamic system that can operate in different language activation states? Three experiments investigated to what extent cross-language phonological co-activation effects in language production are sensitive to the composition of the stimulus list. L1 Dutch-L2 English bilinguals decided whether or not a…

  14. Motor impairments related to brain injury timing in early hemiparesis Part II: abnormal upper extremity joint torque synergies

    PubMed Central

    Sukal-Moulton, Theresa; Krosschell, Kristin J.; Gaebler-Spira, Deborah J.; Dewald, Julius P.A.

    2014-01-01

    Background Extensive neuromotor development occurs early in human life, and the timing of brain injury may affect the resulting motor impairment. In part I of this paper series it was demonstrated that the distribution of weakness in the upper extremity depended on the timing of brain injury in individuals with childhood-onset hemiparesis. Objective The goal of this study was to characterize how timing of brain injury impacts joint torque synergies, or losses of independent joint control. Method Twenty-four individuals with hemiparesis were divided into three groups based on the timing of their injury: before birth (PRE-natal, n=8), around the time of birth (PERI-natal, n=8) and after 6 months of age (POST-natal, n=8). Individuals with hemiparesis, as well as 8 typically developing peers participated in maximal isometric shoulder, elbow, wrist, and finger torque generation tasks while their efforts were recorded by a multiple degree-of-freedom load cell. Motor output in 4 joints of the upper extremity were concurrently measured during 8 primary torque generation tasks to quantify joint torque synergies. Results There were a number of significant coupling patterns identified in individuals with hemiparesis that differed from the typically developing group. POST-natal differences were most noted in the coupling of shoulder abductors with elbow, wrist, and finger flexors, while the PRE-natal group demonstrated significant distal joint coupling with elbow flexion. Conclusion The torque synergies measured provide indirect evidence for the use of bulbospinal pathways in the POST-natal group, while those with earlier injury may utilize relatively preserved ipsilateral corticospinal motor pathways. PMID:23911972

  15. A testing machine for dental air-turbine handpiece characteristics: free-running speed, stall torque, bearing resistance.

    PubMed

    Darvell, Brain W; Dyson, J E

    2005-01-01

    The measurement of performance characteristics of dental air turbine handpieces is of interest with respect to product comparisons, standards specifications and monitoring of bearing longevity in clinical service. Previously, however, bulky and expensive laboratory equipment was required. A portable test machine is described for determining three key characteristics of dental air-turbine handpieces: free-running speed, stall torque and bearing resistance. It relies on a special circuit design for performing a hardware integration of a force signal with respect to rotational position, independent of the rate at which the turbine is allowed to turn during both stall torque and bearing resistance measurements. Free-running speed without the introduction of any imbalance can be readily monitored. From the essential linear relationship between torque and speed, dynamic torque and, hence, power, can then be calculated. In order for these measurements to be performed routinely with the necessary precision of location on the test stage, a detailed procedure for ensuring proper gripping of the handpiece is described. The machine may be used to verify performance claims, standard compliance checks should this be established as appropriate, monitor deterioration with time and usage in the clinical environment and for laboratory investigation of design development. PMID:15765954

  16. Electromagnetic torques, precession and evolution of magnetic inclination of pulsars

    NASA Astrophysics Data System (ADS)

    Zanazzi, J. J.; Lai, Dong

    2015-07-01

    We present analytic calculations of the electromagnetic torques acting on a magnetic neutron star rotating in vacuum, including near-zone torques associated with the inertia of dipole and quadrupole magnetic fields. We incorporate these torques into the rotational dynamics of a rigid-body neutron star, and show that the effects of the inertial torque can be understood as a modification of the moment of inertia tensor of the star. We apply our rotational dynamics equation to the Crab pulsar, including intrinsic distortions of the star and various electromagnetic torques, to investigate the possibility that the counter-alignment of the magnetic inclination angle, as suggested by recent observations, could be explained by pulsar precession. We find that if the effective principal axis of the pulsar is nearly aligned with either the magnetic dipole axis or the rotation axis, then precession may account for the observed counter-alignment over decade time-scales. Over the spindown time-scale of the pulsar, the magnetic inclination angle always decreases.

  17. Reconstruction of Twist Torque in Main Parachute Risers

    NASA Technical Reports Server (NTRS)

    Day, Joshua D.

    2015-01-01

    The reconstruction of twist torque in the Main Parachute Risers of the Capsule Parachute Assembly System (CPAS) has been successfully used to validate CPAS Model Memo conservative twist torque equations. Reconstruction of basic, one degree of freedom drop tests was used to create a functional process for the evaluation of more complex, rigid body simulation. The roll, pitch, and yaw of the body, the fly-out angles of the parachutes, and the relative location of the parachutes to the body are inputs to the torque simulation. The data collected by the Inertial Measurement Unit (IMU) was used to calculate the true torque. The simulation then used photogrammetric and IMU data as inputs into the Model Memo equations. The results were then compared to the true torque results to validate the Model Memo equations. The Model Memo parameters were based off of steel risers and the parameters will need to be re-evaluated for different materials. Photogrammetric data was found to be more accurate than the inertial data in accounting for the relative rotation between payload and cluster. The Model Memo equations were generally a good match and when not matching were generally conservative.

  18. On the torque on birefringent plates induced by quantum fluctuations

    NASA Astrophysics Data System (ADS)

    Munday, Jeremy; Iannuzzi, Davide; Barash, Yuri

    2005-03-01

    We present detailed numerical calculations of the mechanical torque induced by quantum fluctuations of the electromagnetic field on two parallel birefringent plates with in plane optical anisotropy, separated by either vacuum or a liquid (ethanol). The torque is found to vary as sin(2?), where ? represents the angle between the two optical axes, and its magnitude rapidly increases with decreasing plate separation d. For a 40 ?m diameter disk made out of calcite which is kept parallel to a Barium Titanate plate at a distance d=100 nm, the maximum torque (at ?=?/4) is on the order of ˜10-18 N.m. We propose an experiment to observe this torque when the Barium Titanate plate is immersed in ethanol and the other birefringent disk is placed on top of it. In this case the retarded van der Waals (or Casimir-Lifshitz) force between the two birefringent slabs is repulsive. The disk would float parallel to the plate at a distance where its net weight is counterbalanced by the retarded van der Waals repulsion, free to rotate in response to very small driving torques.

  19. Torque on birefringent plates induced by quantum fluctuations

    NASA Astrophysics Data System (ADS)

    Munday, Jeremy N.; Iannuzzi, Davide; Barash, Yuri; Capasso, Federico

    2005-04-01

    We present detailed numerical calculations of the mechanical torque induced by quantum fluctuations on two parallel birefringent plates with in-plane optical anisotropy, separated by either vacuum or a liquid (ethanol). The torque is found to vary as sin(2?) , where ? represents the angle between the two optical axes, and its magnitude rapidly increases with decreasing plate separation d . For a 40?m diameter disk, made out of either quartz or calcite, kept parallel to a barium titanate plate at d?100nm , the maximum torque (at ?=?/4 ) is of the order of ?10-19Nm . We propose an experiment to observe this torque when the barium titanate plate is immersed in ethanol and the other birefringent disk is placed on top of it. In this case the retarded van der Waals (or Casimir-Lifshitz) force between the two birefringent slabs is repulsive. The disk would float parallel to the plate at a distance where its net weight is counterbalanced by the retarded van der Waals repulsion, free to rotate in response to very small driving torques.

  20. Estimation of muscle torque in various combat sports.

    PubMed

    P?dzich, Wioletta; Mastalerz, Andrzej; Sadowski, Jerzy

    2012-01-01

    The purpose of the research was to compare muscle torque of elite combat groups. Twelve taekwondo WTF athletes, twelve taekwondo ITF athletes and nine boxers participated in the study. Measurements of muscle torques were done under static conditions on a special stand which belonged to the Department of Biomechanics. The sum of muscle torque of lower right and left extremities of relative values was significantly higher for taekwondo WTF athletes than for boxers (16%, p < 0.001 for right and 10%, p < 0.05 for left extremities) and taekwondo ITF (10%, p < 0.05 for right and 8% for left extremities). Taekwondo ITF athletes attained significantly higher absolute muscle torque values than boxers for elbow flexors (20%, p < 0.05 for right and 11% for left extremities) and extensors (14% for right and 18%, p < 0.05 for left extremities) and shoulder flexors (10% for right and 12%, p < 0.05 for left extremities) and extensors (11% for right and 1% for left extremities). Taekwondo WTF and taekwondo ITF athletes obtained significantly different relative values of muscle torque of the hip flexors (16%, p < 0.05) and extensors (11%, p < 0.05) of the right extremities. PMID:23394114

  1. Joint Torque Reduction of a Three Dimensional Redundant Planar Manipulator

    PubMed Central

    Yahya, Samer; Moghavvemi, Mahmoud; Almurib, Haider Abbas F.

    2012-01-01

    Research on joint torque reduction in robot manipulators has received considerable attention in recent years. Minimizing the computational complexity of torque optimization and the ability to calculate the magnitude of the joint torque accurately will result in a safe operation without overloading the joint actuators. This paper presents a mechanical design for a three dimensional planar redundant manipulator with the advantage of the reduction in the number of motors needed to control the joint angle, leading to a decrease in the weight of the manipulator. Many efforts have been focused on decreasing the weight of manipulators, such as using lightweight joints design or setting the actuators at the base of the manipulator and using tendons for the transmission of power to these joints. By using the design of this paper, only three motors are needed to control any n degrees of freedom in a three dimensional planar redundant manipulator instead of n motors. Therefore this design is very effective to decrease the weight of the manipulator as well as the number of motors needed to control the manipulator. In this paper, the torque of all the joints are calculated for the proposed manipulator (with three motors) and the conventional three dimensional planar manipulator (with one motor for each degree of freedom) to show the effectiveness of the proposed manipulator for decreasing the weight of the manipulator and minimizing driving joint torques. PMID:22969326

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

    E-print Network

    Shyu, Mei-Ling

    Personal signatures have a long, meaningful history in marketing. For centuries, artists have inscribed.g., Schweppe's Ginger Ale), on promotional materials (e.g., Papa John's Pizza), and even on tangible products

  3. Factors Affecting the Growth and Production of Milk-Clotting Enzyme by Amylomyces rouxii in Rice Liquid Medium

    Microsoft Academic Search

    Pei-Jing Yu; Cheng-Chun Chou

    Summary Amylomyces rouxii is one of the main fungi usually coexisting with yeasts in Chinese yeast ball, the starter of chiu-niang, a traditional Chinese fermented product from rice. In the present study, growth and production of milk-clotting enzyme (MCE) in gelatinous rice liquid culture of A. rouxii as influenced by waxy (gelatinous) rice content in the me- dium (5-20 %),

  4. Coagulase-Negative Staphylococci in Low Birth Weight Infants: Environmental Factors Affecting Biofilm Production in Staphylococcus epidermidis

    Microsoft Academic Search

    Rebecca Bradford; Roziyana Abdul Manan; Suzanne M. Garland; Andrew J. Daley; Margaret A. Deighton

    2011-01-01

    Coagulase-negative staphylococci (CoNS) are the most common cause of biofilm-associated sepsis in very low birth weight infants\\u000a (VLBW). Standard biofilm assays may not predict the pathogenic potential of CoNS since biofilm production is regulated by\\u000a diverse environmental stimuli. Staphylococcus epidermidis isolated from blood cultures from VLBW infants were evaluated for biofilm production in response to various environmental\\u000a stimuli, including intravenous

  5. Short communication: A missense mutation in the PROP1 (prophet of Pit 1) gene affects male fertility and milk production traits in the US Holstein population.

    PubMed

    Lan, X Y; Peñagaricano, F; DeJung, L; Weigel, K A; Khatib, H

    2013-02-01

    In previous studies, we reported significant associations of the POU1F1 pathway genes with reproduction and production traits in several dairy cattle populations. Polymorphisms in genes of this pathway were found to be associated with both female and male fertility traits in dairy cattle. The POU1F1 gene is a direct downstream target for the regulation of the prophet of Pit1 (PROP1) gene, also known as PROP paired-like homeobox 1. Interestingly, the position of PROP1 coincides with a quantitative trait locus affecting ovulation rate in cattle. Therefore, the objective of this study was to investigate whether PROP1 affects fertility and milk production traits in Holstein cattle. Using the DNA pooling sequencing approach, a missense single nucleotide polymorphism that replaces a histidine amino acid with an arginine was detected in exon 3 of PROP1. The arginine allele was found to be associated with a decrease in sire conception rate and an increase in productive life, protein yield, and net merit index in a population of 1,951 Holstein bulls. The transcription factors produced from the histidine and arginine isoforms are known to have different transcription, DNA binding, and regulation activities. As such, we propose that the association of the arginine isoform with decreased bull fertility is likely caused by reduced activity of this allele in male functions. The findings of this study suggest PROP1 polymorphisms as candidates in selection programs for fertility, health, and milk production traits in dairy cattle. PMID:23245960

  6. Seasonal factors affecting egg production and viability of eggs of Acartia tonsa Dana from East Lagoon, Galveston, Texas

    NASA Astrophysics Data System (ADS)

    Ambler, Julie Weills

    1985-06-01

    Egg production and hatching success were determined between March 1981 and March 1982 for the copepod Acartia tonsa Dana from East Lagoon, Galveston, Texas. During three-day experiments in the laboratory, field collected females were fed diets of (1) natural particles collected over the water column, (2) some modification of this and (3) the diatom Thalassiosira weissflogii. The latter served to isolate the effects of temperature and salinity from the effects of the natural particle diets on egg production. Specific rates of egg production, i.e. ?g egg biomass/?g body biomass/time, were consistently higher per unit carbon than nitrogen. The influence of seasonal factors on egg production was compared. Salinity was inversely correlated with egg production, but had less effect than temperature. Positive correlations with temperature were always higher for specific rates per unit nitrogen than carbon. At 15°C, females produced ˜0·25 of their body carbon (or nitrogen) as eggs per day, whereas at 28°C, they produced at least their own biomass as eggs per day (up to 1·80). These high rates of A. tonsa were probably due to its reproductive biology and adaptation to the subtropical habitat as well as the high temperatures and food concentrations. The correlation between specific egg production rate and temperature was less with the natural particle diets than with the unialgal diet. This indicated that the quantity or quality of natural particle assemblages in East Lagoon influenced egg production. Egg viability was highest in the spring, but was not related to diet or the percentage of females with spermatophores.

  7. Reduction of torque pulsation of Stirling engine-compressor system

    NASA Astrophysics Data System (ADS)

    Koda, Toshihide; Fujiwara, Michio; Suganami, Takuya

    The refrigerant compressor driven by a Stirling engine is built into the heat pump system. The Stirling engine-compressor unit generates rolling vibration due to a fluctuation in combined torque. In order to reduce the rolling vibration, the torque characteristics and the linkage construction of the crankshafts are investigated. The investigation was undertaken for the beta-displacer-type and the two-piston-type configurations. In addition to the Stirling engine, a four-stroke internal combustion engine was considered as a reference. When the Stirling engine drives the compressor, the vibration characteristics depend on its linkage construction. The combined torque which caused the rolling vibration was calculated on the Stirling engine-compressor unit.

  8. Mechanics of Re-Torquing in Bolted Flange Connections

    NASA Technical Reports Server (NTRS)

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

    2010-01-01

    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

  9. Advanced torque converters for robotics and space applications

    NASA Technical Reports Server (NTRS)

    1985-01-01

    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.

  10. On the corotation torque for low-mass eccentric planets

    NASA Astrophysics Data System (ADS)

    Fendyke, Stephen M.; Nelson, Richard P.

    2014-01-01

    We present the results of high-resolution 2D simulations of low-mass planets on fixed eccentric orbits embedded in protoplanetary discs. The aim of this study is to determine how the strength of the sustained, non-linear corotation torque experienced by embedded planets varies as a function of orbital eccentricity, disc parameters and planetary mass. In agreement with previous work we find that the corotation torque diminishes as orbital eccentricity, e, increases. Analysis of the time-averaged streamlines in the disc demonstrates that the width of the horseshoe region narrows as the eccentricity increases, and we suggest that this narrowing largely explains the observed decrease in the corotation torque. We employ three distinct methods for estimating the strength of the unsaturated corotation torque from our simulations, and provide an empirical fit to these results. We find that a simple model where the corotation torque, ?C, decreases exponentially with increasing eccentricity [i.e. ?C ? exp (-e/ef)] provides a good global fit to the data with an e-folding eccentricity, ef, that scales linearly with the disc scale height at the planet location. We confirm that this model provides a good fit for planet masses of 5 and 10 M? in our simulations. The formation of planetary systems is likely to involve significant planet-planet interactions that will excite eccentric orbits, and this is likely to influence disc-driven planetary migration through modification of the corotation torque. Our results suggest that high fidelity models of planetary formation should account for these effects.

  11. Kinetic Energy Principle And Neoclassical Toroidal Torque In Tokamaks

    SciTech Connect

    Jong-Kyu Park

    2011-11-07

    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

  12. Conservation of Angular-Momentum in Thermomagnetic Torque Experiments 

    E-print Network

    Vestner, H.; Adair, Thomas W.

    1975-01-01

    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... equation for orbital angular momentum zz ? (Xxmv)+V ~ L =0Dt where Lpp ?P~ t6ppl~t g p1 is the flux of orbital angular momentum, and D 8 -+v VDt Bt where n~ is the local outer unit normal of the gas at 0~. The force the gas exerts on the unit area...

  13. Kinetic energy principle and neoclassical toroidal torque in tokamaks

    SciTech Connect

    Park, Jong-Kyu [Princeton Plasma Physics Laboratory, Princeton, New Jersey 08543 (United States)

    2011-11-15

    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. 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.

  14. Spin torques due to diffusive spin current in magnetic texture

    NASA Astrophysics Data System (ADS)

    Hosono, Kazuhiro; Shibata, Junya; Kohno, Hiroshi; Nozaki, Yukio

    2013-03-01

    We present a microscopic theory of spin torque due to diffusive spin currents induced by spin accumulation. The obtained expression is a natural extension of the existing one due to “local” spin currents associated with ordinary electric currents, and is the reciprocal of the spin motive force which induces charge accumulation as studied recently [J. Shibata and H. Kohno, Phys. Rev. BPRBMDO1098-012110.1103/PhysRevB.84.184408 84, 184408 (2011)]. The result is applied to a domain wall motion in a nonlocal spin injection system, and the torque and force due to diffusive spin current are evaluated.

  15. Ultrafast switching of antiferromagnets via spin-transfer torque

    NASA Astrophysics Data System (ADS)

    Cheng, Ran; Daniels, Matthew W.; Zhu, Jian-Gang; Xiao, Di

    2015-02-01

    Picosecond switching of the staggered antiferromagnetic order is shown to be realizable through spin-transfer torques from a short current pulse. The coupled dynamics of sublattice magnetization is mapped onto a classical pendulum subject to gravity and a driving pulse, where switching occurs if the pendulum acquires sufficient kinetic energy during the pulse to overcome the maximum of the effective gravity potential. The optimal switching scheme is explored through the dependence of switch angle and magnetic loss on the duration and strength of the current pulse. The physics discussed here provides a general route towards multifunctional THz applications via the spin-transfer torque in antiferromagnetic materials.

  16. Biological Magnetometry: Torque on Superparamagnetic Beads in Magnetic Fields

    NASA Astrophysics Data System (ADS)

    van Oene, Maarten M.; Dickinson, Laura E.; Pedaci, Francesco; Köber, Mariana; Dulin, David; Lipfert, Jan; Dekker, Nynke H.

    2015-05-01

    Superparamagnetic beads are widely used in biochemistry and single-molecule biophysics, but the nature of the anisotropy that enables the application of torques remains controversial. To quantitatively investigate the torques experienced by superparamagnetic particles, we use a biological motor to rotate beads in a magnetic field and demonstrate that the underlying potential is ? periodic. In addition, we tether a bead to a single DNA molecule and show that the angular trap stiffness increases nonlinearly with magnetic field strength. Our results indicate that the superparamagnetic beads' anisotropy derives from a nonuniform intrabead distribution of superparamagnetic nanoparticles.

  17. The torque dependence of the H-mode power threshold in hydrogen, deuterium and helium plasmas in DIII-D

    SciTech Connect

    Gohil, P. [General Atomics; Jernigan, T. C. [Oak Ridge National Laboratory (ORNL); Osborne, T.H. [General Atomics, San Diego; Scoville, J. T. [General Atomics, San Diego; Strait, E. J. [General Atomics

    2010-01-01

    On DIII-D, the H-mode power threshold has been determined for hydrogen, deuterium and helium plasmas heated by neutral beam injection and/or by electron cyclotron heating and as a function of the applied torque plasmas for plasma configurations in the favourable ion grad-B drift direction. The H-mode threshold power has been determined to increase with input torque for all the main ion species (hydrogen, deuterium and helium). The H-mode threshold power for similar plasma parameters and configurations is the least for deuterium, followed by helium and hydrogen in that order. The plasma geometry also affects the power threshold, which is dependent on the X-point height.

  18. Alterations of the in vivo torque-velocity relationship of human skeletal muscle following 30 days exposure to simulated microgravity

    NASA Technical Reports Server (NTRS)

    Dudley, Gary A.; Duvoisin, Marc; Convertino, Victor A.; Buchanan, Paul

    1989-01-01

    The effect of a continuous 30-d-long 6-deg headdown bedrest (BR) on the force output ability of skeletal muscles was investigated in human subjects by measuring peak angle specific torque of the knee extensor (KE) and knee flexor (KF) muscle groups of both limbs during unilateral efforts at four speeds (0.52. 1.74, 2.97, and 4.19 rad/sec) during eccentric action. It was found that, for the KE muscle group, the headdown BR resulted in decreases, by 19 percent on the average, of peak angle specific torque; on the other hand, the strength of the KF muscles was not altered significantly. A post-BR recovery for 30 days was found to restore muscle strength of the KE muscle group to about 92 percent of the pre-BR values. Changes of strength were not affected by the type of speed of muscle action.

  19. Spin transfer torque effects in magnetic nanostructures

    NASA Astrophysics Data System (ADS)

    Chen, Tingyong

    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.

  20. Microbial properties of rhizosphere soils as affected by rotation, grafting, and soil sterilization in intensive vegetable production systems

    Microsoft Academic Search

    Yongqiang Tian; Xueyan Zhang; Jun Liu; Qing Chen; Lihong Gao

    2009-01-01

    The increased use of rotation, grafting, and soil sterilization has been documented to increase crop yield in intensive vegetable production systems in China. It is believed that these practices can promote changes in the rhizosphere that enhance early growth of plants. A 2-year greenhouse experiment on tomato double-cropping systems was conducted to investigate the effects of different agricultural treatments on

  1. ALTERING THE PHYSICAL ENVIRONMENT AFFECTS GROWTH, MORPHOGENESIS AND ESSENTIAL OIL PRODUCTION IN MENTHA SPICATA L. SHOOTS IN VITRO

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Altering the physical environment profoundly alters the growth (fresh weight), morphogenesis (leave, root and shoot numbers) and secondary metabolism [i.e., production of the monoterpene (-)-carvone] of Mentha spicata L. (spearmint) shoots cultured on Murashige and Skoog medium. The type of physica...

  2. Microbial Transformation of Triadimefon to Triadimenol in Soils: Selective Production Rates of Triadimenol Stereoisomers Affect Exposure and Risk

    EPA Science Inventory

    The microbial transformation of triadimefon, an agricultural fungicide of the 1,2,4-triazole class, was followed at a nominal concentration of 50 µg/mL over 4 months under aerobic conditions in three different soil types. Rates and products of transformation were measured, as wel...

  3. Factors affecting the variability in cracked and dirty eggs and egg production profitability on an integrated poultry operation

    Microsoft Academic Search

    A. T. Hill

    1976-01-01

    1. A number of factors causing variability in the percentages of cracked, and dirty eggs and weekly standard margin (WSM) of returns from eggs over production costs were examined on an integrated commercial poultry plant in Scotland.2. As the bird aged, the percentage of cracked eggs increased (P <0.01) and the percentage of grade A eggs and WSM decreased (P

  4. Do Proficiency and Study-Abroad Experience Affect Speech Act Production? Analysis of Appropriateness, Accuracy, and Fluency

    ERIC Educational Resources Information Center

    Taguchi, Naoko

    2011-01-01

    This cross-sectional study examined the effect of general proficiency and study-abroad experience in production of speech acts among learners of L2 English. Participants were 25 native speakers of English and 64 Japanese college students of English divided into three groups. Group 1 (n = 22) had lower proficiency and no study-abroad experience.…

  5. Factors affecting yeast growth and protein yield production from orange, plantain and banana wastes processing residues using Candida sp

    Microsoft Academic Search

    A. Adoki

    2008-01-01

    Agricultural residues rich in carbohydrates can be utilized in fermentation proceses to produce microbial protein which in turn can be used to upgrade both human and animal feeds. Studies to determine the factors influencing cell biomass production with Candida sp. using citrus fruit wastes showed that the test strain was capable of meeting its amino acid requirements in culture when

  6. Yeast genes involved in sulfur and nitrogen metabolism affect the production of volatile thiols from Sauvignon Blanc musts.

    PubMed

    Harsch, Michael J; Gardner, Richard C

    2013-01-01

    Two volatile thiols, 3-mercaptohexan-1-ol (3MH), and 3-mercaptohexyl-acetate (3MHA), reminiscent of grapefruit and passion fruit respectively, are critical varietal aroma compounds in Sauvignon Blanc (SB) wines. These aromatic thiols are not present in the grape juice but are synthesized and released by the yeast during alcoholic fermentation. Single deletion mutants of 67 candidate genes in a laboratory strain of Saccharomyces cerevisiae were screened using gas chromatography mass spectrometry for their thiol production after fermentation of SB grape juice. None of the deletions abolished production of the two volatile thiols. However, deletion of 17 genes caused increases or decreases in production by as much as twofold. These 17 genes, mostly related to sulfur and nitrogen metabolism in yeast, may act by altering the regulation of the pathway(s) of thiol production or altering substrate supply. Deleting subsets of these genes in a wine yeast strain gave similar results to the laboratory strain for sulfur pathway genes but showed strain differences for genes involved in nitrogen metabolism. The addition of two nitrogen sources, urea and di-ammonium phosphate, as well as two sulfur compounds, cysteine and S-ethyl-L-cysteine, increased 3MH and 3MHA concentrations in the final wines. Collectively these results suggest that sulfur and nitrogen metabolism are important in regulating the synthesis of 3MH and 3MHA during yeast fermentation of grape juice. PMID:22684328

  7. Studies on Contact Geometry and Limiting Resistant Torque Characteristics of the Variable Torque Slipping Clutch with Skewed Rollers

    NASA Astrophysics Data System (ADS)

    Feng, Ming; Ono, Kyosuke; Mimura, Kenji

    A slipping clutch capable of delivering a constant resistant torque is described in this paper. Its principle is based on the resistance to slipping offered by the askew disposed cylindrical rollers rolling and slipping between the two specially shaped races. There are three types of this slipping clutch, namely the Right, Left and Cross Skewing respectively, which are distinguished by the directions of the roller askew arrangement and the rotation of the driving race. As a newly developed engineering surface, the surface of the races is in the spatial line contact with the skewed cylindrical rollers. After the equations of the race surface is established, the contact geometry of the tangency between the roller and races is investigated. This is essential for understanding the clutch properties and furthering the contact stress and EHL analyses. In addition, the analyzing procedure used here is also helpful for the study of other sophisticated line contact problems. Based on the assumptions of the maximum static friction force and the uniform distribution of the applied axial force along the contact line, the limiting torque characteristics are discussed in detail. The analysis of the maximum resistant torque clarifies the existence of self-locking problems under certain design parameters. On the other hand, the analysis of the minimum resistant torque shows how the resistant torque approaches the minimum values with changes of the geometrical parameters. These analyses provide the design principals for this slipping clutch in order to optimize the torque characteristics. The preliminary experiments are conducted with two types out of the three and the results prove those concluded from the theoretical analyses very well.

  8. Evaluation of moment arm length and fulcrum sensitivity limit in a 10 N·m dead weight torque standard machine

    Microsoft Academic Search

    Atsuhiro Nishino; Koji Ogushi; Kazunaga Ueda

    2010-01-01

    Many torque tools, such as torque wrenches and torque screwdrivers, as well as torque measuring devices (TMDs) with a rated capacity of less than 5N·m are being widely used in industry. Thus, a small-rated-capacity torque standard has to be established as soon as possible. A 10N·m dead weight torque standard machine (10N·m DWTSM) has been under development since 2006 at

  9. Amino acid and glucose metabolism in fed-batch CHO cell culture affects antibody production and glycosylation.

    PubMed

    Fan, Yuzhou; Jimenez Del Val, Ioscani; Müller, Christian; Wagtberg Sen, Jette; Rasmussen, Søren Kofoed; Kontoravdi, Cleo; Weilguny, Dietmar; Andersen, Mikael Rørdam

    2015-03-01

    Fed-batch Chinese hamster ovary (CHO) cell culture is the most commonly used process for IgG production in the biopharmaceutical industry. Amino acid and glucose consumption, cell growth, metabolism, antibody titer, and N-glycosylation patterns are always the major concerns during upstream process optimization, especially media optimization. Gaining knowledge on their interrelations could provide insight for obtaining higher immunoglobulin G (IgG) titer and better controlling glycosylation-related product quality. In this work, different fed-batch processes with two chemically defined proprietary media and feeds were studied using two IgG-producing cell lines. Our results indicate that the balance of glucose and amino acid concentration in the culture is important for cell growth, IgG titer and N-glycosylation. Accordingly, the ideal fate of glucose and amino acids in the culture could be mainly towards energy and recombinant product, respectively. Accumulation of by-products such as NH4(+) and lactate as a consequence of unbalanced nutrient supply to cell activities inhibits cell growth. The levels of Leu and Arg in the culture, which relate to cell growth and IgG productivity, need to be well controlled. Amino acids with the highest consumption rates correlate with the most abundant amino acids present in the produced IgG, and thus require sufficient availability during culture. Case-by-case analysis is necessary for understanding the effect of media and process optimization on glycosylation. We found that in certain cases the presence of Man5 glycan can be linked to limitation of UDP-GlcNAc biosynthesis as a result of insufficient extracellular Gln. However, under different culture conditions, high Man5 levels can also result from low ?-1,3-mannosyl-glycoprotein 2-?-N-acetylglucosaminyltransferase (GnTI) and UDP-GlcNAc transporter activities, which may be attributed to high level of NH4+ in the cell culture. Furthermore, galactosylation of the mAb Fc glycans was found to be limited by UDP-Gal biosynthesis, which was observed to be both cell line and cultivation condition-dependent. Extracellular glucose and glutamine concentrations and uptake rates were positively correlated with intracellular UDP-Gal availability. All these findings are important for optimization of fed-batch culture for improving IgG production and directing glycosylation quality. PMID:25220616

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

    NASA Technical Reports Server (NTRS)

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

    1981-01-01

    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.

  11. The allometry of root production and root loss in Acer rubrum and Betula papyrifera seedings is not affected by elevated atmospheric CO{sub 2}

    SciTech Connect

    Berntson, G.M.; Bazzaz, F.A. [Harvard Univ., Cambridge, MA (United States)

    1995-09-01

    To study the effect of an elevated CO{sub 2} atmosphere on the dynamics of fine root production and loss, seedlings of Acer rubrum and Betula papyrifera were grown in growth containers that allowed for the non-destructive observation of roots. Plants were germinated and grown in either ambient (400 {mu}l l{sup {minus}1}) or elevated (700 {mu}l l{sup {minus}1}) atmospheric CO{sub 2}. Following transplanting, all visible roots were traced onto acetate sheets at 9 day intervals for approximately two month. Plants were harvested at three times through the course of the experiment to derive correction factors for the amount of root present at the surface of the growth containers. Elevated CO{sub 2} resulted in significant increases in the above and belowground growth of Betula but not Acer. Similarly, gross production and gross loss of roots was increased with elevated CO{sub 2} for Betula but not for Acer. The slope of a model II linear regression between root production and root loss was not significantly affected by CO{sub 2}, species or by ontogeny. Thus, root loss appears to scale directly with root production. When elevated CO{sub 2} leads to increases in root production, we can expect that root loss is also increased.

  12. Ripened dairy products differentially affect hepatic lipid content and adipose tissue oxidative stress markers in obese and type 2 diabetic mice.

    PubMed

    Geurts, Lucie; Everard, Amandine; le Ruyet, Pascale; Delzenne, Nathalie M; Cani, Patrice D

    2012-02-29

    Growing evidence suggests that the consumption of dairy products may contribute to a reduced incidence of cardiovascular risk factors, such as obesity, dyslipidemia, and type 2 diabetes. The fatty acid composition in milk fat, the duration of ripening, and the complexity of the food matrices are important factors that may interfere with the physiological impact. In this study, we treated genetic obese and type 2 diabetic mice (db/db) for 4 weeks with different dairy (cheese-based) products, differing by the duration of ripening (0, 15, or 35 days). We found that 35 days ripened product significantly improved glucose tolerance, an effect associated with a decreased adipose tissue lipid peroxide markers (TBARS and NAPDH-oxidase mRNA expression), without affecting body weight, food intake, and fat mass. Both fermented matrices significantly decreased the hepatic lipid content, without modifying plasma triglycerides or plasma total cholesterol. These data suggest that dairy products issued from longer ripening positively impact glucose tolerance, hepatic steatosis, and adipose tissue oxidative stress. Further investigations are warranted to decipher the interactions between milk products fermentation, lipids, and host metabolism. PMID:22300436

  13. The sigma factor sigma s affects antibiotic production and biological control activity of Pseudomonas fluorescens Pf-5.

    PubMed Central

    Sarniguet, A; Kraus, J; Henkels, M D; Muehlchen, A M; Loper, J E

    1995-01-01

    Pseudomonas fluorescens Pf-5, a rhizosphere-inhabiting bacterium that suppresses several soilborne pathogens of plants, produces the antibiotics pyrrolnitrin, pyoluteorin, and 2,4-diacetylphloroglucinol. A gene necessary for pyrrolnitrin production by Pf-5 was identified as rpoS, which encodes the stationary-phase sigma factor sigma s. Several pleiotropic effects of an rpoS mutation in Escherichia coli also were observed in an RpoS- mutant of Pf-5. These included sensitivities of stationary-phase cells to stresses imposed by hydrogen peroxide or high salt concentration. A plasmid containing the cloned wild-type rpoS gene restored pyrrolnitrin production and stress tolerance to the RpoS- mutant of Pf-5. The RpoS- mutant overproduced pyoluteorin and 2,4-diacetyl-phloroglucinol, two antibiotics that inhibit growth of the phytopathogenic fungus Pythium ultimum, and was superior to the wild type in suppression of seedling damping-off of cucumber caused by Pythium ultimum. When inoculated onto cucumber seed at high cell densities, the RpoS- mutant did not survive as well as the wild-type strain on surfaces of developing seedlings. Other stationary-phase-specific phenotypes of Pf-5, such as the production of cyanide and extracellular protease(s) were expressed by the RpoS- mutant, suggesting that sigma s is only one of the sigma factors required for the transcription of genes in stationary-phase cells of P. fluorescens. These results indicate that a sigma factor encoded by rpoS influences antibiotic production, biological control activity, and survival of P. fluorescens on plant surfaces. PMID:8618880

  14. Diets rich in Maillard reaction products affect protein digestibility in adolescent males aged 11-14 y1-3

    Microsoft Academic Search

    Isabel Seiquer; José Díaz-Alguacil; Cristina Delgado-Andrade; Magdalena Lopez-Frías; Antonio Munoz Hoyos; Gabriel Galdo; María Pilar Navarro

    Background: Adolescents are nutritionally at risk because of their physiologic needs and dietary habits. Maillard reaction products (MRPs) are widely consumed by this population, mainly as a result of their high intake of fast food and snacks. Objective: We compared the effects of diets with different MRP contents on dietary protein utilization in adolescent males aged 11-14y.Thebrowndiet(BD)wasrichandthewhitediet(WD)was poorinMRPcontent(hydroxymethylfurfural:3.87and0.94mg\\/kg; fluorescence intensity:

  15. Ab initio simulations reveal that reaction dynamics strongly affect product selectivity for the cracking of alkanes over H-MFI.

    PubMed

    Zimmerman, Paul M; Tranca, Diana C; Gomes, Joseph; Lambrecht, Daniel S; Head-Gordon, Martin; Bell, Alexis T

    2012-11-28

    Product selectivity of alkane cracking catalysis in the H-MFI zeolite is investigated using both static and dynamic first-principles quantum mechanics/molecular mechanics simulations. These simulations account for the electrostatic- and shape-selective interactions in the zeolite and provide enthalpic barriers that are closely comparable to experiment. Cracking transition states for n-pentane lead to a metastable intermediate (a local minimum with relatively small barriers to escape to deeper minima) where the proton is shared between two hydrocarbon fragments. The zeolite strongly stabilizes these carbocations compared to the gas phase, and the conversion of this intermediate to more stable species determines the product selectivity. Static reaction pathways on the potential energy surface starting from the metastable intermediate include a variety of possible conversions into more stable products. One-picosecond quasiclassical trajectory simulations performed at 773 K indicate that dynamic paths are substantially more diverse than the potential energy paths. Vibrational motion that is dynamically sampled after the cracking transition state causes spilling of the metastable intermediate into a variety of different products. A nearly 10-fold change in the branching ratio between C2/C3 cracking channels is found upon inclusion of post-transition-state dynamics, relative to static electronic structure calculations. Agreement with experiment is improved by the same factor. Because dynamical effects occur soon after passing through the rate-limiting transition state, it is the dynamics, and not only the potential energy barriers, that determine the catalytic selectivity. This study suggests that selectivity in zeolite catalysis is determined by high temperature pathways that differ significantly from 0 K potential surfaces. PMID:23072346

  16. Precipitation timing and magnitude differentially affect aboveground annual net primary productivity in three perennial species in a Chihuahuan Desert grassland.

    PubMed

    Robertson, Traesha R; Bell, Colin W; Zak, John C; Tissue, David T

    2009-01-01

    Plant productivity in deserts may be more directly responsive to soil water availability than to precipitation. However, measurement of soil moisture alone may not be enough to elucidate plant responses to precipitation pulses, as edaphic factors may influence productivity when soil moisture is adequate. The first objective of the study was to determine the responses of the aboveground annual net primary productivity (ANPP) of three perennial species (from different functional groups) in a Chihuahuan Desert grassland to variation in natural precipitation (annual and seasonal) and a 25% increase in seasonal precipitation (supplemental watering in summer and winter). Secondly, ANPP responses to other key environmental and soil parameters were explored during dry, average, and wet years over a 5-yr period. ANPP predictors for each species were dynamic. High ANPP in Dasylirion leiophyllum was positively associated with higher soil NH(4)-N and frequent larger precipitation events, while that in Bouteloua curtipendula was positively correlated with frequent small summer precipitation events with short inter-pulse periods and supplemental winter water. Opuntia phaeacantha was responsive to small precipitation events with short inter-pulse periods. Although several studies have shown ANPP increases with increases in precipitation and soil moisture in desert systems, this was not observed here as a universal predictor of ANPP, particularly in dry years. PMID:19076724

  17. Factors Affecting Poly(3-hydroxybutyrate) Production from Oil Palm Frond Juice by Cupriavidus necator (CCUG52238T)

    PubMed Central

    Mohd Zahari, Mior Ahmad Khushairi; Ariffin, Hidayah; Mokhtar, Mohd Noriznan; Salihon, Jailani; Shirai, Yoshihito; Hassan, Mohd Ali

    2012-01-01

    Factors influencing poly(3-hydroxybutyrate) P(3HB) production by??Cupriavidus necator??CCUG52238T utilizing oil palm frond (OPF) juice were clarified in this study. Effects of initial medium pH, agitation speed, and ammonium sulfate (NH4)2SO4 concentration on the production of P(3HB) were investigated in shake flasks experiments using OPF juice as the sole carbon source. The highest P(3HB) content was recorded at pH?7.0, agitation speed of 220?rpm, and (NH4)2SO4 concentration at 0.5?g/L. By culturing the wild-type strain of C. necator under the aforementioned conditions, the cell dry weight (CDW) and P(3HB) content obtained were 9.31?±?0.13?g/L and 45?±?1.5?wt.%, respectively. This accounted for 40% increment of P(3HB) content compared to the nonoptimized condition. In the meanwhile, the effect of dissolved oxygen tension (DOT) on P(3HB) production was investigated in a 2-L bioreactor. Highest CDW (11.37?g/L) and P(3HB) content (44?wt.%) were achieved when DOT level was set at 30%. P(3HB) produced from OPF juice had a tensile strength of 40?MPa and elongation at break of 8% demonstrated that P(3HB) produced from renewable and cheap carbon source is comparable to those produced from commercial substrate. PMID:23133311

  18. Design considerations of sinusoidally excited permanent-magnet Machines for low-torque-ripple applications

    Microsoft Academic Search

    Mohammad S. Islam; Sayeed Mir; Tomy Sebastian; Samuel Underwood

    2005-01-01

    Several high-performance motor drive applications require the motor drive to produce smooth torque with very stringent torque-ripple requirement. This paper is focused on various machine design considerations that can be used in reducing the torque ripple of a sinusoidally excited permanent-magnet brushless dc motor. The paper quantifies the various sources of torque ripple, which may be minimized by appropriate design

  19. Accurate torque control of saturated interior permanent magnet synchronous motors in the field-weakening region

    Microsoft Academic Search

    Michael M. Bech; Torben S. Frederiksen; Per Sandholdt

    2005-01-01

    This paper focuses on accurate torque control of saturated interior permanent magnet (IPM) synchronous motors operating in the field-weakening region, where the maximum torque per ampere strategy cannot be used. First, a simple-but yet accurate-torque calculation method that takes saturation effects into account is devised: the torque developed at an arbitrary (id, iq) may be calculated using only six parameters,

  20. Design of low-torque-ripple synchronous reluctance motors

    Microsoft Academic Search

    Alfredo Vagati; Michele Pastorelli; G. Francheschini; Stefan Cornel Petrache

    1998-01-01

    A design approach oriented to the minimization of torque ripple is presented for synchronous reluctance motors of the transverse-laminated type. First, the possible types of rotors are classified and the more suited rotor structure is evidenced, to be matched to a given stator. Then, the inner rotor design is described, pointing out the low-ripple measures. Lastly, experimental results are given

  1. a New Processing Method for SAW Resonator Torque Response Signal

    Microsoft Academic Search

    C. Xu; Y. Zhang; S. Zhou; X. Zhao

    2011-01-01

    The response signal is of narrow band, high frequency, low SNR (Signal to Noise Ratio) and transient attenuation. Torque applied to the shaft can be acquired from changes of the center frequency. The resolution of FFT (Fast Fourier Transform) method is limited by sampling length. MLE (Maximum Likelihood Estimate) or LSE (Least Square Estimate) is time-consuming. In this paper, GA

  2. Spin torque dynamics with noise in magnetic nanosystems

    Microsoft Academic Search

    J. Swiebodzinski; A. Chudnovskiy; T. Dunn; A. Kamenev

    2010-01-01

    We investigate the role of equilibrium and nonequilibrium noise in the magnetization dynamics on monodomain ferromagnets. Starting from a microscopic model, we present a detailed derivation of the spin shot-noise correlator. We investigate the ramifications of the nonequilibrium noise on the spin torque dynamics, both in the steady-state precessional regime and the spin switching regime. In the latter case, we

  3. The Shaft Torque of a Tandem Axial-Piston Pump

    E-print Network

    Manring, Noah D.

    The Shaft Torque of a Tandem Axial- Piston Pump Noah D. Manring Viral S. Mehta Mechanical of this study is to identify the best indexed position of two rotating groups within a tandem axial-piston pump characteristics of the pump, other vibration aspects of the machine are also expected to be reduced. In particular

  4. PMSM servo system with speed and torque observer

    Microsoft Academic Search

    Xu Dianguo; Wang Hong; Shi Jingzhuo

    2003-01-01

    A compact state observer on PMSM for velocity estimation and rejection of torque ripple is proposed in this paper. By means of the field orientation principle of PMSM, a linear model is used in this state observer. A PID regulator is tuned in it to reject parameter variation. Since the instantaneous velocity can't be estimated truly when speed is very

  5. TORQUE CONTROL OF AN EXOSKELETAL KNEE WITH EMG SIGNALS

    Microsoft Academic Search

    Christian Fleischer; Günter Hommel

    This paper introduces a control scheme and algorithm for a powered orthosis. Recognizing the intended motion is based on real-time evaluation of EMG signals recorded from the operator's leg muscles. The desired motion is executed with a torque controller for an electric linear actuator. In contrast to most of the previous approaches for similar applications, this is performed without pattern

  6. Centre of Mass, Moments, Torque Centre of Mass

    E-print Network

    Feldman, Joel

    Centre of Mass, Moments, Torque Centre of Mass If you support a body at its center of mass (in a uniform gravitational field) it balances perfectly. That's the definition of the center of mass of the body. If the body consists of a m1 m2 m3 m4 finite number of masses m1, · · · , mn attached

  7. Design, Testing and Optimization of a Constant Torque Propeller

    Microsoft Academic Search

    Christoph Burger; Roy Hartfield

    2007-01-01

    This paper examines the viability of a passive variable pitch propeller for small aerial Remotely Piloted Vehicles (RPV's) and Unmanned Aerial Systems (UAS's) using a self adjusting mechanical pitch control mechanism. The work described in this paper includes the design and testing of a mechanical pitch change mechanism based on a constant torque spring for an off-the-shelf propeller. A propeller

  8. Angular dependence of spin-orbit spin transfer torque

    NASA Astrophysics Data System (ADS)

    Lee, Kyung-Jin

    2013-03-01

    Magnetocrystalline anisotropy arises from the modification of electron states by spin-orbit coupling and is determined by integrating over all occupied electron states. On the other hand, current-induced spin transfer torques arise from the changes in torques that arise from changes in electron populations in the presence of a current. In this respect, spin transfer torques caused by spin-orbit coupling can be interpreted as current-induced corrections to the magnetic anisotropy. From this perspective, we expect a close relationship between the magnetic anisotropy and spin-orbit spin torques. We theoretically study this relationship between magnetic anisotropy and spin-orbit spin torque for a ferromagnet subject to Rashba spin-orbit coupling. For a two-dimensional free-electron model, we find that Rashba spin-orbit coupling results in perpendicular magnetic anisotropy and field-like current-induced spin transfer torques. Both quantities acquire nontrivial angular dependence as the spin-orbit coupling becomes comparable to the s-d exchange interaction. This nontrivial angular dependence can be understood from Fermi surface distortion. In the limits where either the spin-orbit coupling or the s-d exchange interaction is much greater than the other, the Fermi surface consists of two concentric circles, but when they are comparable it distorts. These free-electron calculations are in qualitative agreement with ab initio calculations for Co |Pt bilayers, suggesting that the spin-orbit coupling at the interface is non-negligible in comparison to the s-d exchange interaction there. The nontrivial angular dependence of spin-orbit spin torque may be used as an indicator of strong interfacial spin-orbit coupling, because the spin-orbit spin torque that is induced by the spin Hall effect, has a simple sin ? dependence where ? is the angle between the magnetization and the spin injected into a ferromagnet. This work has been done in collaboration with M. D. Stiles and P. M. Haney. Magnetocrystalline anisotropy arises from the modification of electron states by spin-orbit coupling and is determined by integrating over all occupied electron states. On the other hand, current-induced spin transfer torques arise from the changes in torques that arise from changes in electron populations in the presence of a current. In this respect, spin transfer torques caused by spin-orbit coupling can be interpreted as current-induced corrections to the magnetic anisotropy. From this perspective, we expect a close relationship between the magnetic anisotropy and spin-orbit spin torques. We theoretically study this relationship between magnetic anisotropy and spin-orbit spin torque for a ferromagnet subject to Rashba spin-orbit coupling. For a two-dimensional free-electron model, we find that Rashba spin-orbit coupling results in perpendicular magnetic anisotropy and field-like current-induced spin transfer torques. Both quantities acquire nontrivial angular dependence as the spin-orbit coupling becomes comparable to the s-d exchange interaction. This nontrivial angular dependence can be understood from Fermi surface distortion. In the limits where either the spin-orbit coupling or the s-d exchange interaction is much greater than the other, the Fermi surface consists of two concentric circles, but when they are comparable it distorts. These free-electron calculations are in qualitative agreement with ab initio calculations for Co |Pt bilayers, suggesting that the spin-orbit coupling at the interface is non-negligible in comparison to the s-d exchange interaction there. The nontrivial angular dependence of spin-orbit spin torque may be used as an indicator of strong interfacial spin-orbit coupling, because the spin-orbit spin torque that is induced by the spin Hall effect, has a simple sin ? dependence where ? is the angle between the magnetization and the spin injected into a ferromagnet. This work has been done in collaboration with M. D. Stiles and P. M. Haney. This work is supported by NRF grant (2010-0023798).

  9. Casimir Forces and Quantum Electrodynamical Torques: Physics and Nanomechanics

    Microsoft Academic Search

    Federico Capasso; Jeremy N. Munday; Davide Iannuzzi; H. B. Chan

    2007-01-01

    This paper discusses recent developments on quantum electrodynamical (QED) phenomena, such as the Casimir effect, and their use in nanomechanics and nanotechnology in general. Casimir forces and torques arise from quantum fluctuations of vacuum or, more generally, from the zero-point energy of materials and their dependence on the boundary conditions of the electromagnetic fields. Because the latter can be tailored,

  10. High Horsepower and High Torque Performance of EP Gear Lubricants

    Microsoft Academic Search

    R. K. Nelson; L. J. Valentine

    1960-01-01

    In recent months a series of premature gear failures in field operated vehicles produced indications of insufficient load carrying qualities in extreme pressure lubricants of the GL-4 specification conforming to the new Military L-2105A. This condition prompted dynamometer testing in an investigation of horsepower absorption and high torque absorption of these lubricants as compared with extreme pressure lubricants conforming to

  11. Large Torque Variations in Two Soft Gamma Repeaters

    NASA Technical Reports Server (NTRS)

    Woods, Peter M.; Kouveliotou, Chryssa; Gogus, Ersin; Finger, Mark H.; Swank, Jean; Markwardt, Craig B.; Hurley, Kevin; vanderKlis, Michiel; Six, N. Frank (Technical Monitor)

    2001-01-01

    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. The power spectrum of each source is very red (power-law slope approximately -3.5). These power spectra are consistent in normalization with some accreting systems, yet much steeper in slope 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.

  12. Torque magnetometry of an amorphous-alumina/strontium-titanate interface

    E-print Network

    Lee, S. W.

    We report torque magnetometry measurements of an oxide heterostructure consisting of an amorphous Al[subscript 2]O[subscript 3] thin film grown on a crystalline SrTiO[subscript 3] substrate (a-AO/STO) by atomic layer ...

  13. Increasing the dynamic torque per ampere capability of induction machines

    Microsoft Academic Search

    Ian T. Wallace; Donald W. Novotny; Robert D. Lorenz; Deepakraj M. Divan

    1994-01-01

    The objective of this paper is to present a novel means of increasing the dynamic torque per ampere capability of induction machines. The method developed is based on use of an indirect field oriented controller (IFOC) for the induction machine. It is well known that IFOC allows the rotor flux amplitude to be controlled by the d-axis component of stator

  14. Formal Derivation of Direct Torque Control for Induction Machines

    Microsoft Academic Search

    Zakdy Sorchini; Philip T. Krein

    2006-01-01

    Direct torque control (DTC) is an induction motor control technique that has been successful because it explicitly considers the inverter stage and uses few machine parameters, while being more robust to parameter uncertainty than field-oriented control (FOC). This paper presents a formal derivation of DTC based on singular perturbation and nonlinear control tools. The derivation elaborates an explicit relationship between

  15. Torque transmission mechanism via DELSEED loop of F1-ATPase.

    PubMed

    Watanabe, Rikiya; Koyasu, Kazuma; You, Huijuan; Tanigawara, Mizue; Noji, Hiroyuki

    2015-03-10

    F1-ATPase (F1) is an ATP-driven rotary motor in which the three catalytic ? subunits in the stator ring sequentially induce the unidirectional rotation of the rotary ? subunit. Many lines of evidence have revealed open-to-closed conformational transitions in the ? subunit that swing the C-terminal domain inward. This conformational transition causes a C-terminal protruding loop with conserved sequence DELSEED to push the ? subunit. Previous work, where all residues of DELSEED were substituted with glycine to disrupt the specific interaction with ? and introduce conformational flexibility, showed that F1 still rotated, but that the torque was halved, indicating a remarkable impact on torque transmission. In this study, we conducted a stall-and-release experiment on F1 with a glycine-substituted DELSEED loop to investigate the impact of the glycine substitution on torque transmission upon ATP binding and ATP hydrolysis. The mutant F1 showed a significantly reduced angle-dependent change in ATP affinity, whereas there was no change in the equilibrium for ATP hydrolysis. These findings indicate that the DELSEED loop is predominantly responsible for torque transmission upon ATP binding but not for that upon ATP hydrolysis. PMID:25762326

  16. TORQUE AND DRAG CALCULATIONS IN THREE-DIMENSIONAL WELLBORES 

    E-print Network

    Prurapark, Ruktai A.

    2010-07-14

    Torque and drag (T&D) modeling is regarded as extremely helpful in well planning because it helps to predict and prevent drilling problems that might occur during the drilling process. Although T&D software has existed since the 1990s, some...

  17. Drive torque actuation in active surge control of centrifugal compressors

    E-print Network

    Gravdahl, Jan Tommy

    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 speed Compressor performance control Figure 1: The compression system consists of a centrifugal

  18. A comparison of statistical learning approaches for engine torque estimation

    E-print Network

    Paris-Sud XI, Université de

    A comparison of statistical learning approaches for engine torque estimation A. Rakotomamonjy1 , R of the -insensitive norm in SVMs regularization weight factor engine speed (rotation/min) IC internal combustion that have become generalized in modern vehicles for optimizing engine performance, reducing traction wheel

  19. Torsional Vibration Assessment Using Induction Machine Electromagnetic Torque Estimation

    Microsoft Academic Search

    Shahin Hedayati Kia; Humberto Henao; GÉrard-AndrÉ Capolino

    2010-01-01

    Mechanical anomalies such as load troubles, great torque dynamic variations, and torsional oscillations result in the shaft fatigue of electrical machine and other mechanical parts such as bearings and gearboxes. Particularly, the torsional vibration may attain a significant level at resonant frequencies which damage or cause additional lifetime consumption of mechanical parts. In this way, this paper proposes a noninvasive

  20. Torque Calculation Method of Spherical Robotic Wrist Motor

    Microsoft Academic Search

    Sung Hong Won; Ju Lee

    2006-01-01

    This paper presents the torque calculation method of a new spherical robotic wrist motor capable of three degrees of freedom (DOF) motion in a single joint. The spherical motor bases its operation principle on permanent magnet BLDC motor. Prediction of the spherical motor characteristics requires the computation of the exact motor dynamics at each position and angle using 3D finite

  1. The vector alignments of asteroid spins by thermal torques

    E-print Network

    Nesvorny, David

    The vector alignments of asteroid spins by thermal torques David Vokrouhlicky´1 , David Nesvorny´2 ........................................................................................................................................................................................................................... Collisions have been thought to be the dominant process altering asteroid rotations, but recent observations of the Koronis family of asteroids suggest that this may be incorrect. This group of asteroids was formed

  2. Synchronizing and Damping Torques Analysis of Nonlinear Voltage Regulators

    Microsoft Academic Search

    Gurunath Gurrala; Indraneel Sen

    2011-01-01

    This paper makes an attempt to assess the ben- efits of replacing a conventional generator excitation system with a nonlinear voltage regulator using the concepts of synchronizing and damping torque components in a single machine infinite bus (SMIB) system. In recent years, there has been considerable interest in designing nonlinear excitation controllers, which are expected to give better dynamic perfor-

  3. SECOND FLOOR OF OPERATOR'S ROOM, WITH THROTTLE LEVER ABOVE TORQUE ...

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

    SECOND FLOOR OF OPERATOR'S ROOM, WITH THROTTLE LEVER ABOVE TORQUE CONVERTER SWITCH, AT LEFT. MAGNETIC SOLENOID IS IN CENTER, HYDRAULIC BRAKE PUMP IS IN UPPER RIGHT, LOOKING WEST. - Mad River Glen, Single Chair Ski Lift, 62 Mad River Glen Resort Road, Fayston, Washington County, VT

  4. Direct torque control of induction motor-variable switching sectors

    Microsoft Academic Search

    C. G. Mei; S. K. Panda; J. X. Xu; K. W. Lim

    1999-01-01

    An induction motor drive based on direct torque control (DTC) allows high dynamic performance to be obtained with a very simple hysteresis control scheme. In this paper, the problem of stator flux drooping at low speeds has been investigated. By rotating the original flux sectors defined for conventional DTC near the sector boundaries, it is possible to maintain stator flux

  5. Influence of scale on electrostatic forces and torques in AC particulate electrokinetics.

    PubMed

    Jones, T B

    2003-11-01

    Dielectrophoretic forces and torques move and manipulate biological cells, typically of the order of 10 mum ( approximately 10(-5) m) in diameter and ordinarily suspended in aqueous liquids, using electrodes with dimensions around 100 mum ( approximately 10(-4) m). The ability to exploit these same electromechanical effects for particles below 1 mum, that is, <10(-6) m, creates opportunities for remote manipulation and handling of subcellular components, biological macromolecules, and DNA. In this paper, Trimmer's bracket notation is adapted for systematic examination of the scaling laws governing electrokinetic behaviour. The purpose is to shed light on how critical performance measures relevant to the laboratory on a chip are affected by reducing particle sizes and electrode dimensions into the nanometre range. The scaling methodology facilitates consideration of the effect of electrode structure and particle size reduction on voltage, electric field, heating, and response time. Particles with induced moments, dipolar and quadrupolar, as well as permanent dipoles are examined. Separate consideration is given to electrical torque and its application in electrorotation and particle alignment. An eventual goal of these scaling studies is to identify the lower limit on the size of particles that can be manipulated effectively using electrokinetic phenomena. PMID:16468929

  6. An MRF-based device for the torque stiffness control of all movable vertical tails

    NASA Astrophysics Data System (ADS)

    Ameduri, Salvatore; Concilio, Antonio; Gianvito, Antonio; Lemme, Manuel

    2005-05-01

    Aerodynamic control surfaces efficiency is among the major parameters defining the performance of generic aircraft and is strongly affected by geometric and stiffness characteristics. A target of the '3AS' European Project is to estimate the eventual benefits coming from the adaptive control of the torque rigidity of the vertical tail of the EuRAM wind tunnel model. The specific role of CIRA inside the Project is the design of a device based on the "Smart Structures and Materials" concept, able to produce required stiffness variations. Numerical and experimental investigations pointed out that wide excursions of the tail torque rigidity may assure higher efficiency, for several flight regimes. Stiffness variations may be obtained through both classical mechanic-hydraulic and smart systems. In this case, the attainable weight and reliability level may be the significant parameters to drive the choice. For this reason, CIRA focused its efforts also on the design of devices without heavy mechanical parts. The device described in this work is schematically constituted by linear springs linked in a suitably way to the tail shaft. Required stiffness variations are achieved by selectively locking one or more springs, through a hydraulic system, MRF-based. An optimisation process was performed to find the spring features maximising the achievable stiffness range. Then, the hydraulic MRF design was dealt with. Finally, basing on numerical predictions, a prototype was manufactured and an experimental campaign was performed to estimate the device static and dynamic behaviour.

  7. Acceleration tests to determine salient pole synchronous motor inrush currents and torques

    Microsoft Academic Search

    J. H. Dymond; B. Mistry; R. Ong

    2002-01-01

    Determining torque and current at locked rotor and various slips during the acceleration test on a synchronous machine is very tedious and time consuming. Induction and synchronous machines behave similarly during acceleration except that synchronous machine acceleration can include a pulsation torque. Because of the salient poles, conditions exist where the synchronous motor has minimum torque at quadrature axis and

  8. Torque Control Strategies for Snake Robots David Rollinson, Kalyan Vasudev Alwala, Nico Zevallos and Howie Choset

    E-print Network

    Choset, Howie

    Torque Control Strategies for Snake Robots David Rollinson, Kalyan Vasudev Alwala, Nico Zevallos and Howie Choset Abstract-- We present three methods of achieving compliant motion with a snake robot by controlling the torques exerted by the joints of the robot. Two strategies command joint torques based solely

  9. Analytical Method of Torque Calculation for Interior Permanent Magnet Synchronous Machines

    E-print Network

    Tolbert, Leon M.

    method for performing the output torque calculations of an interior permanent magnet synchronous motor (IPMSM) including both permanent magnet and reluctance torque components. This method works well when the inductance values which are required for the calculation of the reluctance torque. The analysis results show

  10. Artificial neural network based torque calculation of switched reluctance motor without locking the rotor

    NASA Astrophysics Data System (ADS)

    Kucuk, Fuat; Goto, Hiroki; Guo, Hai-Jiao; Ichinokura, Osamu

    2009-04-01

    Feedback of motor torque is required in most of switched reluctance (SR) motor applications in order to control torque and its ripple. An SR motor shows highly nonlinear property which does not allow calculating torque analytically. Torque can be directly measured by torque sensor, but it inevitably increases the cost and has to be properly mounted on the motor shaft. Instead of torque sensor, finite element analysis (FEA) may be employed for torque calculation. However, motor modeling and calculation takes relatively long time. The results of FEA may also differ from the actual results. The most convenient way seems to calculate torque from the measured values of rotor position, current, and flux linkage while locking the rotor at definite positions. However, this method needs an extra assembly to lock the rotor. In this study, a novel torque calculation based on artificial neural networks (ANNs) is presented. Magnetizing data are collected while a 6/4 SR motor is running. They need to be interpolated for torque calculation. ANN is very strong tool for data interpolation. ANN based torque estimation is verified on the 6/4 SR motor and is compared by FEA based torque estimation to show its validity.

  11. Robust trajectory following of robots using computed torque structure with VSS

    Microsoft Academic Search

    S. W. WIJESOMA; R. J. RICHARDS

    1990-01-01

    A control approach is proposed for robust accurate trajectory tracking of manipulators based on the computed torque technique and variable-structure systems (VSS) theory. The computed torque structure of the control scheme, most importantly, provides greater insight to the control of manipulators and serves as a unifying framework for control law development. Looking at the control structure from a computed torque

  12. Controller-induced parasitic torque ripples in a PM synchronous motor

    Microsoft Academic Search

    Shaotang Chen; Chandra Namuduri; Sayeed Mir

    2002-01-01

    Permanent magnet (PM) synchronous machines with a sinusoidal back electromotive force are ideally capable of torque-ripple-free operation. However, parasitic torque ripples can still be induced from motor design and controller implementation. This paper focuses on a systematic analysis of possible sources of torque ripple in a PM synchronous machine drive resulting from limitations in the motor controller. It takes into

  13. Online and Offline Rotary Regression Analysis of Torque Estimator for Switched Reluctance Motor Drives

    Microsoft Academic Search

    X. D. Xue; K. W. E. Cheng; S. L. Ho

    2007-01-01

    A new torque estimator for switched reluctance motor (SRM) drives based on 2-D rotary regression analysis is presented in this paper. The proposed torque estimator is composed of a bicubic regressive polynomial as a function of rotor position and input current. The regressive coefficients can be computed offline or online from the torque characteristics acquired either experimentally or from numerical

  14. A novel high torque and low weight segmented switched reluctance motor

    Microsoft Academic Search

    Naresh Vattikuti; Vandana Rallabandi; B. G. Fernandes

    2008-01-01

    Switched reluctance motors (SRM) have advantages of low manufacturing cost, rugged and simple construction and lesser switches in drive circuit. However, some of its disadvantages are noise, torque ripple and low torque per unit volume. A few of these limitations, such as noise and low torque to volume have been mitigated in the segmented switched reluctance machine (SSRM), which uses

  15. MACHINE'S CHARACTERISTICS IDENTIFICATION: A PRELIMINARY STUDY ON DIRECT TORQUE CONTROL FOR SWITCHED RELUCTANCE MOTOR DRIVES

    Microsoft Academic Search

    P. Chancharoensook; M. F. Rahman

    The paper introduces direct torque control for switched reluctance motor drives. The main proposed ideas of this sensorless control are the development of non-linear torque equation, and the accurate identification of machine's characteristics. These two factors are very crucial to the successful implementation of direct torque control in switched reluctance motors. A preliminary work done is the using of finite

  16. Robustness evaluation of deadbeat, direct torque and flux control for induction machine drives

    Microsoft Academic Search

    Björn E. Heinbokel; Robert D. Lorenz

    2009-01-01

    Field oriented control methodologies are one of the dominant industry standards for induction machine drives. While this classical approach has continuously improved, direct torque control (DTC) has emerged as an alternative approach. Deadbeat, direct torque and flux control (DB-DTFC) is a more recent scheme and employs a discrete-time model inversion to achieve decoupled control of both torque and flux with

  17. Analysis of direct torque control in permanent magnet synchronous motor drives

    Microsoft Academic Search

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

    1997-01-01

    This paper describes an investigation of direct torque control (DTC) for permanent magnet synchronous motor (PMSM) drives. It is mathematically proven that the increase of electromagnetic torque in a permanent magnet motor is proportional to the increase of the angle between the stator and rotor flux linkages, and, therefore, the fast torque response can be obtained by adjusting the rotating

  18. SIMULATING REACTIVE/PASSIVE POSTURES BY MEANS OF A HUMAN ACTIVE TORQUE HYBRID MINIMIZATION

    E-print Network

    Rodríguez, Inmaculada

    in the neighbourhood of the joint limits. 1 INTRODUCTION Postures and motions generated by the human body are verySIMULATING REACTIVE/PASSIVE POSTURES BY MEANS OF A HUMAN ACTIVE TORQUE HYBRID MINIMIZATION I.boulic@epfl.ch Keywords: virtual human poses, active muscle torque, passive resistive torque Abstract: In this paper we

  19. Estimation of isometric joint torque from muscle activation and length in intrinsic hand muscle

    Microsoft Academic Search

    Won-Il Park; Hae-Dong Lee; Jung Kim

    2008-01-01

    Due to the complicated relationship between a muscle activation level and isometric joint torques, predicting torques under isometric conditions have been an obstacle to neuromuscular control of robots in the field of human robot interaction (HRI). This study describes the isometric torque estimation of the metacarpophalangeal (MCP) joint of a human hand based on the Hill muscle model. Surface electromyography

  20. Torque, lateral preference, and cognitive ability in primary-grade children

    Microsoft Academic Search

    Corwin Boake; Paul G. Salmon; Gregory Carbone

    1983-01-01

    It has been suggested that torque, the tendency to draw circles in the clockwise direction, is related to left-handedness and is a marker for psychopathology. Results of recent studies conflict with this hypothesis hut are weakened by imprecise definition and unreliable assessment of torque. Measures of torque, lateral preference, and cognitive ability were administered to 181 children in kindergarten and

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

    E-print Network

    Balakrishnan, Venkataramanan "Ragu"

    Spark Ignition Engine Torque Management Grant A. Ingram 1 , Matthew A. Franchek, Venkataramanan the torque of a spark ignition engine equipped with an electronic throttle mass air flow controller constant in order to maintain vehi­ cle drivability. Since the torque of a spark ignition engine varies

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

    E-print Network

    Balakrishnan, Venkataramanan "Ragu"

    Spark Ignition Engine Torque Management Grant A. Ingram1, Matthew A. Franchek, Venkataramanan the torque of a spark ignition engine equipped with an electronic throttle mass air flow controller in order to maintain vehi- cle drivability. Since the torque of a spark ignition engine varies with air

  3. Direct Torque and Flux Regulation of an IPM Synchronous Motor Drive Using Variable Structure Control Approach

    Microsoft Academic Search

    Zhuang Xu; M. Faz Rahman

    2007-01-01

    To enhance high performance of an interior permanent magnet synchronous motor drive, a nonlinear variable structure controller is proposed for the control of torque and stator flux linkage. The modeling and experimental results show that the torque and flux ripples have been significantly minimized. The fast responses and robustness merits of the classic direct torque control are preserved by eliminating

  4. Optimization of average and cogging torque in 3-phase IPM motor drives

    Microsoft Academic Search

    Leila Parsa; Lei Hao; Hamid A. Toliyat

    2002-01-01

    In this paper, an interior permanent magnet (IPM) brushless DC motor for traction applications is analyzed. The effect of magnetization direction, number of stator slots and current waveform on torque pulsation are examined. A three-phase, four-pole IPM motor is considered for the study. The finite element method is used to calculate the torque, reluctance torque, back iron flux density, tooth

  5. A variable structure torque and flux controller for a DTC IPM synchronous motor drive

    Microsoft Academic Search

    Zhuang Xu; M. F. Rahman

    2004-01-01

    A variable structure controller (VSC) is proposed for direct torque and stator flux linkage control of an interior permanent magnet (IPM) synchronous motor. In comparison with conventional direct torque control (DTC), the inverter switching frequency of the proposed drive is constant and controllable by using space vector modulation (SVM), the torque and flux ripple are significantly reduced. The fast response

  6. AUTOMOTIVE DIESEL MAINTENANCE 2. UNIT V, AUTOMATIC TRANSMISSIONS--TORQUE CONVERTER.

    ERIC Educational Resources Information Center

    Human Engineering Inst., Cleveland, OH.

    THIS MODULE OF A 25-MODULE COURSE IS DESIGNED TO DEVELOP AN UNDERSTANDING OF THE OPERATION AND MAINTENANCE OF TORQUE CONVERTERS USED ON DIESEL POWERED VEHICLES. TOPICS ARE (1) FLUID COUPLINGS (LOCATION AND PURPOSE), (2) PRINCIPLES OF OPERATION, (3) TORQUE CONVERRS, (4) TORQMATIC CONVERTER, (5) THREE STAGE, THREE ELEMENT TORQUE CONVERTER, AND (6)…

  7. Spin-transfer torque generated by a topological insulator.

    PubMed

    Mellnik, A R; Lee, J S; Richardella, A; Grab, J L; Mintun, P J; Fischer, M H; Vaezi, A; Manchon, A; Kim, E-A; Samarth, N; Ralph, D C

    2014-07-24

    Magnetic devices are a leading contender for the implementation of memory and logic technologies that are non-volatile, that can scale to high density and high speed, and that do not wear out. However, widespread application of magnetic memory and logic devices will require the development of efficient mechanisms for reorienting their magnetization using the least possible current and power. There has been considerable recent progress in this effort; in particular, it has been discovered that spin-orbit interactions in heavy-metal/ferromagnet bilayers can produce strong current-driven torques on the magnetic layer, via the spin Hall effect in the heavy metal or the Rashba-Edelstein effect in the ferromagnet. In the search for materials to provide even more efficient spin-orbit-induced torques, some proposals have suggested topological insulators, which possess a surface state in which the effects of spin-orbit coupling are maximal in the sense that an electron's spin orientation is fixed relative to its propagation direction. Here we report experiments showing that charge current flowing in-plane in a thin film of the topological insulator bismuth selenide (Bi2Se3) at room temperature can indeed exert a strong spin-transfer torque on an adjacent ferromagnetic permalloy (Ni81Fe19) thin film, with a direction consistent with that expected from the topological surface state. We find that the strength of the torque per unit charge current density in Bi2Se3 is greater than for any source of spin-transfer torque measured so far, even for non-ideal topological insulator films in which the surface states coexist with bulk conduction. Our data suggest that topological insulators could enable very efficient electrical manipulation of magnetic materials at room temperature, for memory and logic applications. PMID:25056062

  8. Spinal circuits can accommodate interaction torques during multijoint limb movements.

    PubMed

    Buhrmann, Thomas; Di Paolo, Ezequiel A

    2014-01-01

    The dynamic interaction of limb segments during movements that involve multiple joints creates torques in one joint due to motion about another. Evidence shows that such interaction torques are taken into account during the planning or control of movement in humans. Two alternative hypotheses could explain the compensation of these dynamic torques. One involves the use of internal models to centrally compute predicted interaction torques and their explicit compensation through anticipatory adjustment of descending motor commands. The alternative, based on the equilibrium-point hypothesis, claims that descending signals can be simple and related to the desired movement kinematics only, while spinal feedback mechanisms are responsible for the appropriate creation and coordination of dynamic muscle forces. Partial supporting evidence exists in each case. However, until now no model has explicitly shown, in the case of the second hypothesis, whether peripheral feedback is really sufficient on its own for coordinating the motion of several joints while at the same time accommodating intersegmental interaction torques. Here we propose a minimal computational model to examine this question. Using a biomechanics simulation of a two-joint arm controlled by spinal neural circuitry, we show for the first time that it is indeed possible for the neuromusculoskeletal system to transform simple descending control signals into muscle activation patterns that accommodate interaction forces depending on their direction and magnitude. This is achieved without the aid of any central predictive signal. Even though the model makes various simplifications and abstractions compared to the complexities involved in the control of human arm movements, the finding lends plausibility to the hypothesis that some multijoint movements can in principle be controlled even in the absence of internal models of intersegmental dynamics or learned compensatory motor signals. PMID:25426061

  9. Effect of q-profile structure on intrinsic torque reversals

    NASA Astrophysics Data System (ADS)

    Lu, Zhixin

    2014-10-01

    Intrinsic toroidal rotation plays an important role in mitigating macroinstability and regulating turbulent transport in ITER, where neutral beams are not sufficient to provide the requisite torque. Recent experiments on C-Mod with LHCD observed rotation reversal related to a change in the q profile. In this work, we focus on understanding the physics of intrinsic rotation reversals in LHCD plasmas, using nonlinear, global gyro-kinetic simulations and analysis of mode structure and spectrum symmetry breaking. The sensitive dependence of turbulent residual stress on magnetic shear is identified and characterized. The basic residual stress is non-vanishing when the k-parallel spectrum symmetry is broken, e.g., by E × B shear induced radial shift, non-uniformity in turbulence intensity, etc.. It is found that at low magnetic shear, the poloidal harmonics can shift strongly in the radial direction, as a feature of non-local effects, due to radial propagation and amplitude variation of the mode. This new symmetry breaking mechanism leads to a change in the sign of spectrum averaged parallel wave vector and thus the direction of intrinsic torque. Theoretical study shows that the competition between magnetic drift and ion kinetic effects determines the non-local effects and the structure of the asymmetry. Specifically, it is found that the direction of the intrinsic torque changes from counter- to co-current in the core, when magnetic shear decreases through a critical value. A critical shear ?R = 0 . 2 ~ 0 . 5 for reversal of CTEM-induced intrinsic torque found by simulation is consistent with that from the LHCD C-Mod reversal experiments. In addition, simulations indicate ?R = 1 ~ 2 for the reversal of ITG-induced torque, a prediction which can be tested by experiments. This work is supported by CER and CMTFO, UCSD and U.S. DOE-PPPL Contract DE-AC02-09CH11466.

  10. Asymmetric warming significantly affects net primary production, but not ecosystem carbon balances of forest and grassland ecosystems in northern China

    PubMed Central

    Su, Hongxin; Feng, Jinchao; Axmacher, Jan C.; Sang, Weiguo

    2015-01-01

    We combine the process-based ecosystem model (Biome-BGC) with climate change-scenarios based on both RegCM3 model outputs and historic observed trends to quantify differential effects of symmetric and asymmetric warming on ecosystem net primary productivity (NPP), heterotrophic respiration (Rh) and net ecosystem productivity (NEP) of six ecosystem types representing different climatic zones of northern China. Analysis of covariance shows that NPP is significant greater at most ecosystems under the various environmental change scenarios once temperature asymmetries are taken into consideration. However, these differences do not lead to significant differences in NEP, which indicates that asymmetry in climate change does not result in significant alterations of the overall carbon balance in the dominating forest or grassland ecosystems. Overall, NPP, Rh and NEP are regulated by highly interrelated effects of increases in temperature and atmospheric CO2 concentrations and precipitation changes, while the magnitude of these effects strongly varies across the six sites. Further studies underpinned by suitable experiments are nonetheless required to further improve the performance of ecosystem models and confirm the validity of these model predictions. This is crucial for a sound understanding of the mechanisms controlling the variability in asymmetric warming effects on ecosystem structure and functioning. PMID:25766381

  11. The Timing of IFN? Production Affects Early Innate Responses to Listeria monocytogenes and Determines the Overall Outcome of Lethal Infection

    PubMed Central

    Pontiroli, Francesca; Dussurget, Olivier; Zanoni, Ivan; Urbano, Matteo; Beretta, Ottavio; Granucci, Francesca; Ricciardi-Castagnoli, Paola; Cossart, Pascale; Foti, Maria

    2012-01-01

    Dendritic cells (DCs) and natural killer (NK) cells are essential components of the innate immunity and play a crucial role in the first phase of host defense against infections and tumors. Listeria monocytogenes (Lm) is an intracellular pathogen that colonizes the cytosol of eukaryotic cells. Recent findings have shown Lm specifically in splenic CD8a+ DCs shortly after intravenous infection. We examined gene expression profiles of mouse DCs exposed to Lm to elucidate the molecular mechanisms underlying DCs interaction with Lm. Using a functional genomics approach, we found that Lm infection induced a cluster of late response genes including type I IFNs and interferon responsive genes (IRGs) in DCs. Type I INFs were produced at the maximal level only at 24 h post infection indicating that the regulation of IFNs in the context of Lm infection is delayed compared to the rapid response observed with viral pathogens. We showed that during Lm infection, IFN? production and cytotoxic activity were severely impaired in NK cells compared to E. coli infection. These defects were restored by providing an exogenous source of IFN? during the initial phase of bacterial challenge. Moreover, when treated with IFN? during early infection, NK cells were able to reduce bacterial titer in the spleen and significantly improve survival of infected mice. These findings show that the timing of IFN? production is fundamental to the efficient control of the bacterium during the early innate phase of Lm infection. PMID:22912878

  12. Factors affecting the machinability of GFR\\/epoxy composites

    Microsoft Academic Search

    I. El-Sonbaty; U. A. Khashaba; T. Machaly

    2004-01-01

    Drilling is an essential operation in the assembly of the structural frames of automobiles and aircrafts. The life of the joint can be critically affected by the quality of the drilled holes. The main objective of the present paper is to investigate the influence of some parameters on the thrust force, torque and surface roughness in drilling processes of fiber-reinforced

  13. Coordinated turn-and-reach movements. I. Anticipatory compensation for self-generated coriolis and interaction torques

    NASA Technical Reports Server (NTRS)

    Pigeon, Pascale; Bortolami, Simone B.; DiZio, Paul; Lackner, James R.

    2003-01-01

    When reaching movements involve simultaneous trunk rotation, additional interaction torques are generated on the arm that are absent when the trunk is stable. To explore whether the CNS compensates for such self-generated interaction torques, we recorded hand trajectories in reaching tasks involving various amplitudes and velocities of arm extension and trunk rotation. Subjects pointed to three targets on a surface slightly above waist level. Two of the target locations were chosen so that a similar arm configuration relative to the trunk would be required for reaching to them, one of these targets requiring substantial trunk rotation, the other very little. Significant trunk rotation was necessary to reach the third target, but the arm's radial distance to the body remained virtually unchanged. Subjects reached at two speeds-a natural pace (slow) and rapidly (fast)-under normal lighting and in total darkness. Trunk angular velocity and finger velocity relative to the trunk were higher in the fast conditions but were not affected by the presence or absence of vision. Peak trunk velocity increased with increasing trunk rotation up to a maximum of 200 degrees /s. In slow movements, peak finger velocity relative to the trunk was smaller when trunk rotation was necessary to reach the targets. In fast movements, peak finger velocity was approximately 1.7 m/s for all targets. Finger trajectories were more curved when reaching movements involved substantial trunk rotation; however, the terminal errors and the maximal deviation of the trajectory from a straight line were comparable in slow and fast movements. This pattern indicates that the larger Coriolis, centripetal, and inertial interaction torques generated during rapid reaches were compensated by additional joint torques. Trajectory characteristics did not vary with the presence or absence of vision, indicating that visual feedback was unnecessary for anticipatory compensations. In all reaches involving trunk rotation, the finger movement generally occurred entirely during the trunk movement, indicating that the CNS did not minimize Coriolis forces incumbent on trunk rotation by sequencing the arm and trunk motions into a turn followed by a reach. A simplified model of the arm/trunk system revealed that additional interaction torques generated on the arm during voluntary turning and reaching were equivalent to < or =1.8 g (1 g = 9.81 m/s(2)) of external force at the elbow but did not degrade performance. In slow-rotation room studies involving reaching movements during passive rotation, Coriolis forces as small as 0.2 g greatly deflect movement trajectories and endpoints. We conclude that compensatory motor innervations are engaged in a predictive fashion to counteract impending self-generated interaction torques during voluntary reaching movements.

  14. Iloprost treatment reduces TNF-alpha production and TNF-RII expression in critical limb ischemia patients without affecting IL6.

    PubMed

    Di Renzo, M; Pieragalli, D; Meini, S; De Franco, V; Pompella, G; Auteri, A; Pasqui, A L

    2005-11-01

    Iloprost, a stable prostacyclin analogue, regulates expression of genes that are involved in inflammation and in cell growth and inhibits the in vitro production of cytokines. We evaluated the effect of an in vivo weekly iloprost treatment on TNF-alpha and IL6 monocyte production (evaluated by ELISA), on monocyte apoptosis (Annexin V/uptake of propidium iodide by flow cytometry) and on peripheral blood mononuclear cell (PBMC) TNF-alpha receptors (TNF-RI and TNF-RII) mRNA expression (RT-PCR) in 14 atherosclerotic critical limb ischemia patients. PBMC were stimulated with LPS for 24h. TNF-alpha production was significantly reduced by iloprost whereas IL6 production was not affected. Iloprost did not accelerate monocyte apoptosis. TNF-RI mRNA expression was not modified by iloprost, whereas TNF-RII mRNA expression was significantly reduced. Our data show that iloprost may have anti-inflammatory effects in addition to the well-known vasodilatatory and anti-aggregant ones. PMID:16095891

  15. Identification and characterization of the Streptomyces globisporus 1912 regulatory gene lndYR that affects sporulation and antibiotic production.

    PubMed

    Ostash, Bohdan; Rebets, Yuriy; Myronovskyy, Maksym; Tsypik, Olga; Ostash, Iryna; Kulachkovskyy, Oleksandr; Datsyuk, Yuriy; Nakamura, Tatsunosuke; Walker, Suzanne; Fedorenko, Victor

    2011-04-01

    Here, we report the identification and functional characterization of the Streptomyces globisporus 1912 gene lndYR, which encodes a GntR-like regulator of the YtrA subfamily. Disruption of lndYR arrested sporulation and antibiotic production in S. globisporus. The results of in vivo and in vitro studies revealed that the ABC transporter genes lndW-lndW2 are targets of LndYR repressive action. In Streptomyces coelicolor M145, lndYR overexpression caused a significant increase in the amount of extracellular actinorhodin. We suggest that lndYR controls the transcription of transport system genes in response to an as-yet-unidentified signal. Features that distinguish lndYR-based regulation from other known regulators are discussed. PMID:21292750

  16. Feed frequency in a sequencing batch reactor strongly affects the production of polyhydroxyalkanoates (PHAs) from volatile fatty acids.

    PubMed

    Valentino, Francesco; Beccari, Mario; Fraraccio, Serena; Zanaroli, Giulio; Majone, Mauro

    2014-06-25

    The production of polyhydroxyalkanoates (PHAs) by activated sludge selected in a sequencing batch reactor (SBR) has been investigated. Several SBR runs were performed at the same applied organic load rate (OLR), hydraulic retention time (HRT) and feed concentration (8.5 g COD L(-1) of volatile fatty acids, VFAs) under aerobic conditions. The effect of the feeding time was only evaluated with a cycle length of 8h; for this particular cycle length, an increase in the storage response was observed by increasing the rate at which the substrate was fed into the reactor (at a fixed feeding frequency). Furthermore, a significantly stronger effect was observed by decreasing the cycle length from 8h to 6h and then to 2h, changing the feed frequency or changing the organic load given per cycle (all of the other conditions remained the same): the length of the feast phase decreased from 26 to 20.0 and then to 19.7% of the overall cycle length, respectively, due to an increase in the substrate removal rate. This removal rate was high and similar for the runs with cycle lengths of 2h and 6h in the SBR. This result was due to an increase in the selective pressure and the specific storage properties of the selected biomass. The highest polymer productivity after long-term accumulation batch tests was 1.7 g PHA L(-1)d(-1), with PHA content in the biomass of approximately 50% on a COD basis under nitrogen limitation. The DGGE profiles showed that the good storage performance correlated to the development of Lampropedia hyalina, which was only observed in the SBR runs characterized by a shorter cycle length. PMID:24184912

  17. Regulatory T Cells Negatively Affect IL-2 Production of Effector T Cells through CD39/Adenosine Pathway in HIV Infection

    PubMed Central

    Jenabian, Mohammad-Ali; Seddiki, Nabila; Yatim, Ahmad; Carriere, Matthieu; Hulin, Anne; Younas, Mehwish; Ghadimi, Elnaz; Kök, Ayrin; Routy, Jean-Pierre; Tremblay, Alain; Sévigny, Jean; Lelievre, Jean-Daniel; Levy, Yves

    2013-01-01

    The mechanisms by which Regulatory T cells suppress IL-2 production of effector CD4+ T cells in pathological conditions are unclear. A subpopulation of human Treg expresses the ectoenzyme CD39, which in association with CD73 converts ATP/ADP/AMP to adenosine. We show here that Treg/CD39+ suppress IL-2 expression of activated CD4+ T-cells more efficiently than Treg/CD39?. This inhibition is due to the demethylation of an essential CpG site of the il-2 gene promoter, which was reversed by an anti-CD39 mAb. By recapitulating the events downstream CD39/adenosine receptor (A2AR) axis, we show that A2AR agonist and soluble cAMP inhibit CpG site demethylation of the il-2 gene promoter. A high frequency of Treg/CD39+ is associated with a low clinical outcome in HIV infection. We show here that CD4+ T-cells from HIV-1 infected individuals express high levels of A2AR and intracellular cAMP. Following in vitro stimulation, these cells exhibit a lower degree of demethylation of il-2 gene promoter associated with a lower expression of IL-2, compared to healthy individuals. These results extend previous data on the role of Treg in HIV infection by filling the gap between expansion of Treg/CD39+ in HIV infection and the suppression of CD4+ T-cell function through inhibition of IL-2 production. PMID:23658513

  18. Peptide Production and Decay Rates Affect the Quantitative Accuracy of Protein Cleavage Isotope Dilution Mass Spectrometry (PC-IDMS)*

    PubMed Central

    Shuford, Christopher M.; Sederoff, Ronald R.; Chiang, Vincent L.; Muddiman, David C.

    2012-01-01

    No consensus has been reached on the proper time to add stable-isotope labeled (SIL) peptides in protein cleavage isotope dilution mass spectrometry workflows. While quantifying 24 monolignol pathway enzymes in the xylem tissue of Populus trichocarpa, we compared the protein concentrations obtained when adding the SIL standard peptides concurrently with the enzyme or after quenching of the digestion (i.e. postdigestion) and observed discrepancies for nearly all tryptic peptides investigated. In some cases, greater than 30-fold differences were observed. To explain these differences and potentially correct for them, we developed a mathematical model based on pseudo-first-order kinetics to account for the dynamic production and decay (e.g. degradation and precipitation) of the native peptide targets in conjunction with the decay of the SIL peptide standards. A time course study of the digests confirmed the results predicted by the proposed model and revealed that the discrepancy between concurrent and postdigestion introduction of the SIL standards was related to differential decay experienced by the SIL peptide and the native peptide in each method. Given these results, we propose concurrent introduction of the SIL peptide is most appropriate, though not free from bias. Mathematical modeling of this method reveals that overestimation of protein quantities would still result when rapid peptide decay occurs and that this bias would be further exaggerated by slow proteolysis. We derive a simple equation to estimate the bias for each peptide based on the relative rates of production and decay. According to this equation, nearly half of the peptides evaluated here were estimated to have quantitative errors greater than 10% and in a few cases over 100%. We conclude that the instability of peptides can often significantly bias the protein quantities measured in protein cleavage isotope dilution mass spectrometry-based assays and suggest peptide stability be made a priority when selecting peptides to use for quantification. PMID:22595788

  19. TNF? altered inflammatory responses, impaired health and productivity, but did not affect glucose or lipid metabolism in early-lactation dairy cows.

    PubMed

    Yuan, Kai; Farney, Jaymelynn K; Mamedova, Laman K; Sordillo, Lorraine M; Bradford, Barry J

    2013-01-01

    Inflammation may be a major contributing factor to peripartum metabolic disorders in dairy cattle. We tested whether administering an inflammatory cytokine, recombinant bovine tumor necrosis factor-? (rbTNF?), affects milk production, metabolism, and health during this period. Thirty-three Holstein cows (9 primiparous and 24 multiparous) were randomly assigned to 1 of 3 treatments at parturition. Treatments were 0 (Control), 1.5, or 3.0 µg/kg body weight rbTNF?, which were administered once daily by subcutaneous injection for the first 7 days of lactation. Statistical contrasts were used to evaluate the treatment and dose effects of rbTNF? administration. Plasma TNF? concentrations at 16 h post-administration tended to be increased (P<0.10) by rbTNF? administration, but no dose effect (P>0.10) was detected; rbTNF? treatments increased (P<0.01) concentrations of plasma haptoglobin. Most plasma eicosanoids were not affected (P>0.10) by rbTNF? administration, but 6 out of 16 measured eicosanoids changed (P<0.05) over the first week of lactation, reflecting elevated inflammatory mediators in the days immediately following parturition. Dry matter and water intake, milk yield, and milk fat and protein yields were all decreased (P<0.05) by rbTNF? treatments by 15 to 18%. Concentrations of plasma glucose, insulin, ?-hydroxybutyrate, non-esterified fatty acids, triglyceride, 3-methylhistidine, and liver triglyceride were unaffected (P>0.10) by rbTNF? treatment. Glucose turnover rate was unaffected (P=0.18) by rbTNF? administration. The higher dose of rbTNF? tended to increase the risk of cows developing one or more health disorders (P=0.08). Taken together, these results indicate that administration of rbTNF? daily for the first 7 days of lactation altered inflammatory responses, impaired milk production and health, but did not significantly affect liver triglyceride accumulation or nutrient metabolism in dairy cows. PMID:24260367

  20. TNF? Altered Inflammatory Responses, Impaired Health and Productivity, but Did Not Affect Glucose or Lipid Metabolism in Early-Lactation Dairy Cows

    PubMed Central

    Mamedova, Laman K.; Sordillo, Lorraine M.; Bradford, Barry J.

    2013-01-01

    Inflammation may be a major contributing factor to peripartum metabolic disorders in dairy cattle. We tested whether administering an inflammatory cytokine, recombinant bovine tumor necrosis factor-? (rbTNF?), affects milk production, metabolism, and health during this period. Thirty-three Holstein cows (9 primiparous and 24 multiparous) were randomly assigned to 1 of 3 treatments at parturition. Treatments were 0 (Control), 1.5, or 3.0 µg/kg body weight rbTNF?, which were administered once daily by subcutaneous injection for the first 7 days of lactation. Statistical contrasts were used to evaluate the treatment and dose effects of rbTNF? administration. Plasma TNF? concentrations at 16 h post-administration tended to be increased (P<0.10) by rbTNF? administration, but no dose effect (P>0.10) was detected; rbTNF? treatments increased (P<0.01) concentrations of plasma haptoglobin. Most plasma eicosanoids were not affected (P>0.10) by rbTNF? administration, but 6 out of 16 measured eicosanoids changed (P<0.05) over the first week of lactation, reflecting elevated inflammatory mediators in the days immediately following parturition. Dry matter and water intake, milk yield, and milk fat and protein yields were all decreased (P<0.05) by rbTNF? treatments by 15 to 18%. Concentrations of plasma glucose, insulin, ?-hydroxybutyrate, non-esterified fatty acids, triglyceride, 3-methylhistidine, and liver triglyceride were unaffected (P>0.10) by rbTNF? treatment. Glucose turnover rate was unaffected (P?=?0.18) by rbTNF? administration. The higher dose of rbTNF? tended to increase the risk of cows developing one or more health disorders (P?=?0.08). Taken together, these results indicate that administration of rbTNF? daily for the first 7 days of lactation altered inflammatory responses, impaired milk production and health, but did not significantly affect liver triglyceride accumulation or nutrient metabolism in dairy cows. PMID:24260367