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Sample records for stall standing behavior

  1. Ingestive behavior of lambs confined in individual and group stalls.

    Science.gov (United States)

    Filho, A Eustáquio; Carvalho, G G P; Pires, A J V; Silva, R R; Santos, P E F; Murta, R M; Pereira, F M

    2014-02-01

    The experiment was conducted to evaluate the ingestive behavior of lambs confined in individual and group stalls. We used thirty-four lambs in their growing phase, aged an average of three months, with mean initial live weight of 17.8±5.2 kg. They were allotted in a completely randomized design with 24 animals kept in individual stalls and 10 animals confined as a group. The experiment lasted for a total of 74 days, and the first 14 days were dedicated to the animals' adaption to the management, facilities and diets. The data collection period lasted 60 days, divided into three 20-d periods for the behavior evaluation. The animals were subjected to five days of visual observation during the experiment period, by the quantification of 24 h a day, with evaluations on the 15th day of each period and an interim evaluation consisting of two consecutive days on the 30th and 31st day of the experiment. The animals confined as a group consumed less (pbehavior.

  2. Wider stall space affects behavior, lesion scores, and productivity of gestating sows.

    Science.gov (United States)

    Salak-Johnson, J L; DeDecker, A E; Levitin, H A; McGarry, B M

    2015-10-01

    Limited space allowance within the standard gestation stall is an important welfare concern because it restricts the ability of the sow to make postural adjustments and hinders her ability to perform natural behaviors. Therefore, we evaluated the impacts of increasing stall space and/or providing sows the freedom to access a small pen area on sow well-being using multiple welfare metrics. A total of 96 primi- and multiparous crossbred sows were randomly assigned in groups of 4 sows/treatment across 8 replicates to 1 of 3 stall treatments (TRT): standard stall (CTL; dimensions: 61 by 216 cm), width-adjustable stall (flex stall [FLX]; dimensions: adjustable width of 56 to 79 cm by 216 cm), or an individual walk-in/lock-in stall with access to a small communal open-pen area at the rear of the stall (free-access stall [FAS]; dimensions: 69 by 226 cm). Lesion scores, behavior, and immune and productivity traits were measured at various gestational days throughout the study. Total lesion scores were greatest for sows in FAS and least for sows in FLX ( pregnancy progressed, lesion scores increased among sows in CTL ( postural behaviors and sham chew behavior were affected by TRT ( changes in postural behaviors, lesion severity scores, and other sow traits. Moreover, compromised welfare measures found among sows in various stall environments may be partly attributed to the specific constraints of each stall system such as restricted stall space in CTL, insufficient floor space in the open-pen area of the FAS system, and gate design of the FLX (e.g., direction of bars and feeder space). These results also indicate that parity and gestational day are additional factors that may exacerbate the effects of restricted stall space or insufficient pen space, further compromising sow well-being.

  3. Study of Near-Stall Flow Behavior in a Modern Transonic Fan with Composite Sweep

    Science.gov (United States)

    Hah, Chunill; Shin, Hyoun-Woo

    2011-01-01

    Detailed flow behavior in a modern transonic fan with a composite sweep is investigated in this paper. Both unsteady Reynolds-averaged Navier-Stokes (URANS) and Large Eddy Simulation (LES) methods are applied to investigate the flow field over a wide operating range. The calculated flow fields are compared with the data from an array of high-frequency response pressure transducers embedded in the fan casing. The current study shows that a relatively fine computational grid is required to resolve the flow field adequately and to calculate the pressure rise across the fan correctly. The calculated flow field shows detailed flow structure near the fan rotor tip region. Due to the introduction of composite sweep toward the rotor tip, the flow structure at the rotor tip is much more stable compared to that of the conventional blade design. The passage shock stays very close to the leading edge at the rotor tip even at the throttle limit. On the other hand, the passage shock becomes stronger and detaches earlier from the blade passage at the radius where the blade sweep is in the opposite direction. The interaction between the tip clearance vortex and the passage shock becomes intense as the fan operates toward the stall limit, and tip clearance vortex breakdown occurs at near-stall operation. URANS calculates the time-averaged flow field fairly well. Details of measured RMS static pressure are not calculated with sufficient accuracy with URANS. On the other hand, LES calculates details of the measured unsteady flow features in the current transonic fan with composite sweep fairly well and reveals the flow mechanism behind the measured unsteady flow field.

  4. The computation of the post-stall behavior of a circulation controlled airfoil

    Science.gov (United States)

    Linton, Samuel W.

    1993-01-01

    The physics of the circulation controlled airfoil is complex and poorly understood, particularly with regards to jet stall, which is the eventual breakdown of lift augmentation by the jet at some sufficiently high blowing rate. The present paper describes the numerical simulation of stalled and unstalled flows over a two-dimensional circulation controlled airfoil using a fully implicit Navier-Stokes code, and the comparison with experimental results. Mach numbers of 0.3 and 0.5 and jet total to freestream pressure ratios of 1.4 and 1.8 are investigated. The Baldwin-Lomax and k-epsilon turbulence models are used, each modified to include the effect of strong streamline curvature. The numerical solutions of the post-stall circulation controlled airfoil show a highly regular unsteady periodic flowfield. This is the result of an alternation between adverse pressure gradient and shock induced separation of the boundary layer on the airfoil trailing edge.

  5. Associations of herd- and cow-level factors, cow lying behavior, and risk of elevated somatic cell count in free-stall housed lactating dairy cows.

    Science.gov (United States)

    Watters, M E Alexandrea; Meijer, Karin M A; Barkema, Herman W; Leslie, Kenneth E; von Keyserlingk, Marina A G; Devries, Trevor J

    2013-09-01

    Recent evidence suggests that the risk of intramammary infection in dairy cows is related to lying patterns. The objectives of this study were to quantify the standing and lying behavior of dairy cows milked 3×/d, determine the cow- and herd-level factors associated with these behaviors, and relate these findings to the risk of an elevated somatic cell count (SCC). Five commercial free-stall dairy herds in Eastern Ontario, milking 3×/d, were enrolled in a longitudinal study. Forty Holstein-Friesian cows/herd were randomly selected as focal animals based on days in milk (cow SCC was recorded at the beginning of each period and end of the final period. Elevated SCC (eSCC) was used as an indicator of subclinical mastitis. A new incident eSCC was defined as an individual cow that started the period with a SCC cows for hygiene and lameness. Throughout the course of the study, cows averaged 11.2h/d of lying time, split into 8.6 lying bouts/d that were on average 84.6 min in length. Later lactation cows had longer daily lying times that were split into fewer lying bouts of longer duration than cows earlier in lactation. Lame cows had longer daily lying times and lying bout durations than non-lame cows. Cows with greater milk yield had lower lying times than lower producing cows. Average post-milking standing time across the study herds was 103 min. Manipulation of feed (feed delivery or push-up) by the stockperson, in the hour before milking or shortly thereafter, resulted in the longest post-milking standing times. Over the study period, 48 new eSCC were detected, resulting in a mean herd incidence rate of 0.91 eSCC/cow-year at risk for all study herds. A non-linear relationship between post-milking standing time and eSCC incidence was found; compared to those cows that lie down cows that lie down for the first time >90 min after milking had a lower risk of acquiring a new eSCC. The risk of experiencing an eSCC was also increased in multiparous cows, and in those cows

  6. Calculation of Rotor Performance and Loads Under Stalled Conditions

    National Research Council Canada - National Science Library

    Yeo, Hyeonsoo

    2003-01-01

    Rotor behavior in stalled conditions is investigated using wind tunnel test data of a 1/10-scale CH-47B/C type rotor, which provides a set of test conditions extending from unstalled to light stall...

  7. Clinical ketosis and standing behavior in transition cows.

    Science.gov (United States)

    Itle, A J; Huzzey, J M; Weary, D M; von Keyserlingk, M A G

    2015-01-01

    Ketosis is a common disease in dairy cattle, especially in the days after calving, and it is often undiagnosed. The objective of this study was to compare the standing behavior of dairy cows with and without ketosis during the days around calving to determine if changes in this behavior could be useful in the early identification of sick cows. Serum β-hydroxybutyrate (BHBA) was measured in 184 cows on a commercial dairy farm twice weekly from 2 to 21d after calving. Standing behavior was measured from 7d before calving to 21d after calving using data loggers. Retrospectively, 15 cows with clinical ketosis (3 consecutive BHBA samples >1.2mmol/L and at least one sample of BHBA >2.9mmol/L) were matched with 15 nonketotic cows (BHBA ketosis occurred 4.5±2.1d after calving. Total daily standing time was longer for clinically ketotic cows compared with nonketotic cows during wk -1 (14.3±0.6 vs. 12.0±0.7h/d) and on d 0 (17.2±0.9 vs. 12.7±0.9h/d) but did not differ during the other periods. Clinically ketotic cows exhibited fewer standing bouts compared with nonketotic cows on d 0 only (14.6±1.9 vs. 20.9±1.8bouts/d). Average standing bout duration was also longer for clinically ketotic cows on d 0 compared with nonketotic cows [71.3min/bout (CI: 59.3 to 85.5) vs. 35.8min/bout (CI: 29.8 to 42.9)] but was not different during the other periods. Differences in standing behavior in the week before and on the day of calving may be useful for the early detection of clinical ketosis in dairy cows. Copyright © 2015 American Dairy Science Association. Published by Elsevier Inc. All rights reserved.

  8. 2014 Behavioral Health and Performance Standing Review Panel

    Science.gov (United States)

    Steinberg, Susan; Leon, Gloria; Dimsdale, Joel; Balkin, Thomas; Bono, Joyce; Caldwell, John; Joiner, Thomas; Paulus, Martin; Zaccaro, Stephen

    2015-01-01

    The 2014 Behavioral Health and Performance (BHP) Standing Review Panel (from here on referred to as the SRP) met for a site visit in Houston, TX on December 17 - 18, 2014. The SRP reviewed the updated research plan for the Risk of Performance Errors Due to Fatigue Resulting from Sleep Loss, Circadian Desynchronization, Extended Wakefulness, and Work Overload (Sleep Risk) and also received a status update on the Risk of Adverse Behavioral Conditions and Psychiatric Disorders (BMed Risk) and the Risk of Performance Decrements Due to Inadequate Cooperation, Coordination, Communication, and Psychosocial Adaptation within a Team (Team Risk).

  9. Construction of hydrogenation stalls for explosions

    Energy Technology Data Exchange (ETDEWEB)

    Raichle, L.

    1943-05-03

    This report contained explanations for different questions that had been asked by the Association of Chemical Manufacturers. The first item discussed was the pressure occurring in hydrogenation stalls in hydrogen explosions. The pressures actually used were much smaller than the maximum design pressure due to burning gases being allowed to escape from the top and front of the stalls since these areas were open and it could not be assumed that the whole stall space was filled with a 32% hydrogen concentration at the beginning of an explosion. The second item discussed was specifications and rules for the building of hydrogenation stalls. These included the calculations for simple wind pressure according to the Building Code with the usual safety factors and the calculations for an inner pressure of 300 kg/m/sup 2/ with the usual safety factors. An explanation of a stall explosion in Poelitz and reinforced stall construction in Poelitz were two other items that were discussed. Appendix I of the report involved maximum pressures and temperature in hydrogen explosions. Diagram I was involved with this. Appendix II discussed the behavior of a hydrogen flame at high emerging velocities and Appendix III discussed stall construction at Poelitz.

  10. Mind the movement: Frontal asymmetry stands for behavioral motivation, bilateral frontal activation for behavior.

    Science.gov (United States)

    Rodrigues, Johannes; Müller, Mathias; Mühlberger, Andreas; Hewig, Johannes

    2018-01-01

    Frontal asymmetry has been investigated over the past 30 years, and several theories have been developed about its meaning. The original theory of Davidson and its diversification by Harmon-Jones & Allen allocated approach motivation to relative left frontal brain activity and withdrawal motivation to relative right frontal brain activity. Hewig and colleagues extended this theory by adding bilateral frontal activation representing a biological correlate of the behavioral activation system if actual behavior is shown. Wacker and colleagues formulated a theory related to the revised reinforcement sensitivity theory by Gray & McNaughton. Here, relative left frontal brain activation represents the revised behavioral activation system and behavior, while relative right frontal brain activation represents the revised behavioral inhibition system, representing the experience of conflict. These theories were investigated with a newly developed paradigm where participants were able to move around freely in a virtual T maze via joystick while having their EEG recorded. Analyzing the influence of frontal brain activation during this virtual reality task on observable behavior for 30 participants, we found more relative left frontal brain activation during approach behavior and more relative right brain activation for withdrawal behavior of any kind. Additionally, there was more bilateral frontal brain activation when participants were engaged in behavior compared to doing nothing. Hence, this study provides evidence for the idea that frontal asymmetry stands for behavioral approach or avoidance motivation, and bilateral frontal activation stands for behavior. Additionally, observable behavior is not only determined by frontal asymmetry, but also by relevant traits. © 2017 Society for Psychophysiological Research.

  11. Airfoil stall interpreted through linear stability analysis

    Science.gov (United States)

    Busquet, Denis; Juniper, Matthew; Richez, Francois; Marquet, Olivier; Sipp, Denis

    2017-11-01

    Although airfoil stall has been widely investigated, the origin of this phenomenon, which manifests as a sudden drop of lift, is still not clearly understood. In the specific case of static stall, multiple steady solutions have been identified experimentally and numerically around the stall angle. We are interested here in investigating the stability of these steady solutions so as to first model and then control the dynamics. The study is performed on a 2D helicopter blade airfoil OA209 at low Mach number, M 0.2 and high Reynolds number, Re 1.8 ×106 . Steady RANS computation using a Spalart-Allmaras model is coupled with continuation methods (pseudo-arclength and Newton's method) to obtain steady states for several angles of incidence. The results show one upper branch (high lift), one lower branch (low lift) connected by a middle branch, characterizing an hysteresis phenomenon. A linear stability analysis performed around these equilibrium states highlights a mode responsible for stall, which starts with a low frequency oscillation. A bifurcation scenario is deduced from the behaviour of this mode. To shed light on the nonlinear behavior, a low order nonlinear model is created with the same linear stability behavior as that observed for that airfoil.

  12. Exploratory study of the effects of wing-leading-edge modifications on the stall/spin behavior of a light general aviation airplane

    Science.gov (United States)

    1979-01-01

    Configurations with full-span and segmented leading-edge flaps and full-span and segmented leading-edge droop were tested. Studies were conducted with wind-tunnel models, with an outdoor radio-controlled model, and with a full-scale airplane. Results show that wing-leading-edge modifications can produce large effects on stall/spin characteristics, particularly on spin resistance. One outboard wing-leading-edge modification tested significantly improved lateral stability at stall, spin resistance, and developed spin characteristics.

  13. A CFD Database for Airfoils and Wings at Post-Stall Angles of Attack

    Science.gov (United States)

    Petrilli, Justin; Paul, Ryan; Gopalarathnam, Ashok; Frink, Neal T.

    2013-01-01

    This paper presents selected results from an ongoing effort to develop an aerodynamic database from Reynolds-Averaged Navier-Stokes (RANS) computational analysis of airfoils and wings at stall and post-stall angles of attack. The data obtained from this effort will be used for validation and refinement of a low-order post-stall prediction method developed at NCSU, and to fill existing gaps in high angle of attack data in the literature. Such data could have potential applications in post-stall flight dynamics, helicopter aerodynamics and wind turbine aerodynamics. An overview of the NASA TetrUSS CFD package used for the RANS computational approach is presented. Detailed results for three airfoils are presented to compare their stall and post-stall behavior. The results for finite wings at stall and post-stall conditions focus on the effects of taper-ratio and sweep angle, with particular attention to whether the sectional flows can be approximated using two-dimensional flow over a stalled airfoil. While this approximation seems reasonable for unswept wings even at post-stall conditions, significant spanwise flow on stalled swept wings preclude the use of two-dimensional data to model sectional flows on swept wings. Thus, further effort is needed in low-order aerodynamic modeling of swept wings at stalled conditions.

  14. Cow preference and usage of free stalls compared with an open pack area.

    Science.gov (United States)

    Fregonesi, J A; von Keyserlingk, M A G; Weary, D M

    2009-11-01

    Free-stall housing systems are designed to provide a comfortable and hygienic lying area, but some aspects of stall design may restrict usage by cows. The aim of this study was to compare free-stall housing with a comparable lying area (open pack) without stall partitions. We predicted that cows would spend more time lying down and standing in the bedded area when provided access to an open pack than when in free stalls. We also predicted that cows would spend less time standing outside of the lying area and less time perching with the front 2 hooves in the lying area when using the open pack. Groups (n = 8) of 12 cows each were provided access to either the open pack or stalls. After a 7-d adaptation period, each group was tested sequentially in the 2 treatments for 3 d each. This no-choice phase was followed by an 8-d choice phase during which cows had simultaneous access to both treatments. During the no-choice phase, cows spent more time lying down (13.03 +/- 0.24 vs. 12.48 +/- 0.24 h/d) and standing with all 4 hooves in the bedded area (0.96 +/- 0.12 vs. 0.41 +/- 0.12 h/d) of the open pack than in the stalls. During the choice phase, cows spent more time lying down (7.20 +/- 0.29 vs. 5.86 +/- 0.29 h/d) and standing with all 4 hooves in the bedded area (0.58 +/- 0.07 vs. 0.12 +/- 0.07 h/d) of the open pack than in the stalls. In both the no-choice (1.66 +/- 0.24 vs. 0.55 +/- 0.24 h/d) and choice (0.55 +/- 0.07 vs. 0.29 +/- 0.07 h/d) phases, cows spent more time standing with just 2 hooves in the stalls than in the open pack. In conclusion, cows spent more time lying and standing with all 4 hooves in the bedded open pack than in the stalls. Additionally, cows spent more time standing in the alley and standing with just the front 2 hooves on the bedding in the stalls than in the bedded open pack; increased standing time on wet concrete is a known risk factor for lameness.

  15. Theoretical Antecedents of Standing at Work: An Experience Sampling Approach Using the Theory of Planned Behavior

    Science.gov (United States)

    Meyer, M. Renée Umstattd; Wu, Cindy; Walsh, Shana M.

    2016-01-01

    Time spent sitting has been associated with an increased risk of diabetes, cancer, obesity, and mental health impairments. However, 75% of Americans spend most of their days sitting, with work-sitting accounting for 63% of total daily sitting time. Little research examining theory-based antecedents of standing or sitting has been conducted. This lack of solid groundwork makes it difficult to design effective intervention strategies to decrease sitting behaviors. Using the Theory of Planned Behavior (TPB) as our theoretical lens to better understand factors related with beneficial standing behaviors already being practiced, we examined relationships between TPB constructs and time spent standing at work among “positive deviants” (those successful in behavior change). Experience sampling methodology (ESM), 4 times a day (midmorning, before lunch, afternoon, and before leaving work) for 5 consecutive workdays (Monday to Friday), was used to assess employees' standing time. TPB scales assessing attitude (α = 0.81–0.84), norms (α = 0.83), perceived behavioral control (α = 0.77), and intention (α = 0.78) were developed using recommended methods and collected once on the Friday before the ESM surveys started. ESM data are hierarchically nested, therefore we tested our hypotheses using multilevel structural equation modeling with Mplus. Hourly full-time university employees (n = 50; 70.6% female, 84.3% white, mean age = 44 (SD = 11), 88.2% in full-time staff positions) with sedentary occupation types (time at desk while working ≥6 hours/day) participated. A total of 871 daily surveys were completed. Only perceived behavioral control (β = 0.45, p deviance approach to enhance perceived behavioral control, in addition to implementing environmental changes like installing standing desks. PMID:29546189

  16. Theoretical Antecedents of Standing at Work: An Experience Sampling Approach Using the Theory of Planned Behavior

    Directory of Open Access Journals (Sweden)

    M. Renée Umstattd Meyer

    2016-09-01

    Full Text Available Time spent sitting has been associated with an increased risk of diabetes, cancer, obesity, and mental health impairments. However, 75% of Americans spend most of their days sitting, with work-sitting accounting for 63% of total daily sitting time. Little research examining theory-based antecedents of standing or sitting has been conducted. This lack of solid groundwork makes it difficult to design effective intervention strategies to decrease sitting behaviors. Using the Theory of Planned Behavior (TPB as our theoretical lens to better understand factors related with beneficial standing behaviors already being practiced, we examined relationships between TPB constructs and time spent standing at work among “positive deviants” (those successful in behavior change. Experience sampling methodology (ESM, 4 times a day (midmorning, before lunch, afternoon, and before leaving work for 5 consecutive workdays (Monday to Friday, was used to assess employees’ standing time. TPB scales assessing attitude (α = 0.81–0.84, norms (α = 0.83, perceived behavioral control (α = 0.77, and intention (α = 0.78 were developed using recommended methods and collected once on the Friday before the ESM surveys started. ESM data are hierarchically nested, therefore we tested our hypotheses using multilevel structural equation modeling with Mplus. Hourly full-time university employees (n = 50; 70.6% female, 84.3% white, mean age = 44 (SD = 11, 88.2%in full-time staff positions with sedentary occupation types (time at desk while working ≥6 hours/day participated. A total of 871 daily surveys were completed. Only perceived behavioral control (β = 0.45, p < 0.05 was related with work-standing at the event-level (model fit: just fit; mediation through intention was not supported. This is the first study to examine theoretical antecedents of real-time work-standing in a naturalistic field setting among positive deviants. These relationships should be further

  17. 14 CFR 25.103 - Stall speed.

    Science.gov (United States)

    2010-01-01

    ... 14 Aeronautics and Space 1 2010-01-01 2010-01-01 false Stall speed. 25.103 Section 25.103... STANDARDS: TRANSPORT CATEGORY AIRPLANES Flight Performance § 25.103 Stall speed. (a) The reference stall speed, VSR, is a calibrated airspeed defined by the applicant. VSR may not be less than a 1-g stall...

  18. DAILY TIME BUDGET OF DAIRY COWS HOUSED IN TIE STALL BARNS, DURING TOTAL CONFINEMENT

    Directory of Open Access Journals (Sweden)

    D. GAVOJDIAN

    2009-10-01

    Full Text Available Although individual and social behavior of cattle has been studied extensively under pasture and loose housing conditions, similar behavioral data for partial or total confinement housing are limited. Essentially, the 24- h time budget represents the net response of a cow to her environment (Grant, 2003. Daily time budget was first introduced by Grant and Albright (in 2000 for cows housed in free-stall environment. Choices in stabling and management affect the behavior, health, longevity and performance of cows. Behavior while resting, eating, ruminating, urinating or defecating provides additional information about comfort. In the current study were used ten Romanian Black and White multiparous cows, housed in a tie stall barn 24 hours per day. Experiments were carried out during the cold season, in February 2008. Cows monitored were in their first hundred days of lactation. In our study cows spent resting on average 379.9 minutes (6.33 hours, value that represents 26.38 % from the days interval. Time devoted to feeding was on average 341.9 minutes (5.69 hours, in 17.5 periods. Rumination had place on average in 17.3 periods and a total time of 517.5 minutes (8.62 hours. Cows adopted lying position on average 581.2 minutes (40.36% from 24-h and standing position on average in 858.7 minutes (59.63% from 24-h.

  19. Dynamic behavior of microscale particles controlled by standing bulk acoustic waves

    Energy Technology Data Exchange (ETDEWEB)

    Greenhall, J.; Raeymaekers, B., E-mail: bart.raeymaekers@utah.edu [Department of Mechanical Engineering, University of Utah, Salt Lake City, Utah 84112 (United States); Guevara Vasquez, F. [Department of Mathematics, University of Utah, Salt Lake City, Utah 84112 (United States)

    2014-10-06

    We analyze the dynamic behavior of a spherical microparticle submerged in a fluid medium, driven to the node of a standing bulk acoustic wave created by two opposing transducers. We derive the dynamics of the fluid-particle system taking into account the acoustic radiation force and the time-dependent and time-independent drag force acting on the particle. Using this dynamic model, we characterize the transient and steady-state behavior of the fluid-particle system as a function of the particle and fluid properties and the transducer operating parameters. The results show that the settling time and percent overshoot of the particle trajectory are dependent on the ratio of the acoustic radiation force and time-independent damping force. In addition, we show that the particle oscillates around the node of the standing wave with an amplitude that depends on the ratio of the time-dependent drag forces and the particle inertia.

  20. 14 CFR 25.203 - Stall characteristics.

    Science.gov (United States)

    2010-01-01

    ... 14 Aeronautics and Space 1 2010-01-01 2010-01-01 false Stall characteristics. 25.203 Section 25.203 Aeronautics and Space FEDERAL AVIATION ADMINISTRATION, DEPARTMENT OF TRANSPORTATION AIRCRAFT AIRWORTHINESS STANDARDS: TRANSPORT CATEGORY AIRPLANES Flight Stalls § 25.203 Stall characteristics. (a) It must...

  1. Emotion-related personality traits and peer social standing: unique and interactive effects in cyberbullying behaviors.

    Science.gov (United States)

    Ciucci, Enrica; Baroncelli, Andrea

    2014-09-01

    This study investigated the unique and interactive effects of emotion-related personality traits (i.e., callousness and uncaring traits) and peer social standing (i.e., social preference and perceived popularity) on cyberbullying behaviors in preadolescents. A total of 529 preadolescents (247 boys, 46.69%) were recruited from an Italian middle school (Mage=12 years and 7 months; SD=1 year and 2 months). The participants primarily consisted of Italian children (91.12%). A series of binary logistic regression analyses parted by gender were conducted to examine the main and interactive effects of self-reported emotion-related variables and peer-reported social standing in the prediction of self-reported cyberbullying behaviors, while controlling for cyber victimization and grade effects. In girls, an uncaring disposition was directly associated with cyberbullying behaviors, whereas in boys this association only emerged for those with low perceived popularity. Our results indicated that, in developing anti(cyber)bullying programs, school researchers and practitioners should jointly consider individual and contextual factors.

  2. Behavioral Health and Performance (BHP) Standing Review Panel (SRP) Final Report

    Science.gov (United States)

    Suedfeld, Peter; Bootzin, Richard; Harvey, Allison; Leon, Gloria; Musson, David; Oltmanns, Thomas; Paulus, Martin

    2010-01-01

    The first meeting of the Behavioral Health and Performance (BHP) Standing Review Panel (SRP) was held in Houston, TX on November 1-3, 2009. Our task was to assess the Integrated Research Plan (IRP) related to the fields covered in the SRP charge (see section VIII). Having considered and discussed the extensive materials distributed prior to the meeting, and the highly informative briefings by the NASA BHP Human Research Program (HRP) personnel during the site visit, the SRP agreed that the IRP is comprehensive and was developed carefully. Question and answer periods with the presenters were particularly productive and helpful to the SRP. The presenters' willingness to share information and positive responses to the SRP's suggestions were greatly appreciated. Although the IRP and related documents are impressive, the SRP does have a number of recommendations regarding both the overall plan and its component parts.

  3. Clutch-Starting Stalled Research Students

    Science.gov (United States)

    Ahern, Kathy; Manathunga, Catherine

    2004-01-01

    Many research students go through periods where their research seems to stall, their motivation drops, and they seem unable to make any progress. As supervisors, we attempt to remain alert to signs that our student's progress has stalled. Drawing on cognitive strategies, this article explores a problem-solving model supervisors can use to identify…

  4. Basis for an Active Stall Avoidance System

    Directory of Open Access Journals (Sweden)

    Richard Schulze

    2000-01-01

    Full Text Available A single-stage subsonic compressor was examined with respect to compressor instabilities. During the inception of rotating stall, the transients of the pressure rise and mass flow were measured as well as their hysteresis. The development of the stall cell and the characteristics of the unstable operating range were determined.

  5. Dynamic stall characterization using modal analysis of phase-averaged pressure distributions

    Science.gov (United States)

    Harms, Tanner; Nikoueeyan, Pourya; Naughton, Jonathan

    2017-11-01

    Dynamic stall characterization by means of surface pressure measurements can simplify the time and cost associated with experimental investigation of unsteady airfoil aerodynamics. A unique test capability has been developed at University of Wyoming over the past few years that allows for time and cost efficient measurement of dynamic stall. A variety of rotorcraft and wind turbine airfoils have been tested under a variety of pitch oscillation conditions resulting in a range of dynamic stall behavior. Formation, development and separation of different flow structures are responsible for the complex aerodynamic loading behavior experienced during dynamic stall. These structures have unique signatures on the pressure distribution over the airfoil. This work investigates the statistical behavior of phase-averaged pressure distribution for different types of dynamic stall by means of modal analysis. The use of different modes to identify specific flow structures is being investigated. The use of these modes for different types of dynamic stall can provide a new approach for understanding and categorizing these flows. This work uses airfoil data acquired under Army contract W911W60160C-0021, DOE Grant DE-SC0001261, and a gift from BP Alternative Energy North America, Inc.

  6. The influence of elevated feed stalls on feeding behaviour of lactating dairy cows

    Directory of Open Access Journals (Sweden)

    Barbara Benz

    2014-10-01

    Full Text Available The performance level of high yielding cows can only be guaranteed by high quality forage and high feed intake. An about 15–20 cm elevated and 160 cm long feed stall with rubber flooring doesn’t only offer undisturbed meals but also a yielding and dry standing surface. In a pilot stable with 130 dairy cows (German Simmental the feeding alley was subsequently equipped with elevated feed stalls. The results show that animals frequented the feeding barn less often while the duration of single meals prolonged. The specific behavioural changes differed depending on milk yield and number of lactation.

  7. Early Adolescents' Social Standing in Peer Groups: Behavioral Correlates of Stability and Change

    Science.gov (United States)

    Lansford, Jennifer E.; Killeya-Jones, Ley A.; Miller, Shari; Costanzo, Philip R.

    2009-01-01

    Sociometric nominations, social cognitive maps, and self-report questionnaires were completed in consecutive years by 327 students (56% girls) followed longitudinally from grade 7 to grade 8 to examine the stability of social standing in peer groups and correlates of changes in social standing. Social preference, perceived popularity, network…

  8. The Relevance of the Dynamic Stall Effect for Transient

    DEFF Research Database (Denmark)

    Jauch, Clemens; Sørensen, Poul; Bak-Jensen, Birgitte

    2005-01-01

    This article describes a methodology to quantify the influence of dynamic stall on transient fault operations of active-stall turbines. The model of the dynamic stall effect is introduced briefly. The behaviour of the dynamic stall model during a transient fault operation is described mathematica...

  9. Biomimetic Wind Turbine Design with Lift Enhancing Periodic Stall

    NARCIS (Netherlands)

    Stamhuis, Eize Jan

    2017-01-01

    A wind turbine includes a rotor; a blade; and a periodic stall system. The periodic stall system selectively moves at least part of the blade in an oscillating motion whereby an angle of incidence continuously varies to invoke periodic stall. The periodic stall system can move the entire blade or

  10. The Physiologic and Behavioral Implications of Playing Active and Sedentary Video Games in a Seated and Standing Position.

    Science.gov (United States)

    Sanders, Gabriel J; Rebold, Michael; Peacock, Corey A; Williamson, Meagan L; Santo, Antonio S; Barkley, Jacob E

    Previous studies have assessed physiologic response while playing video games per manufacturer instructions with participants standing during active video game play and seated during sedentary game play. It is not known whether an assigned seated or standing position affects positional preference and oxygen consumption (VO2) while gaming. The purpose of the study was to assess VO2 and preference of playing active and sedentary video games in a seated and standing position. VO2 was assessed in 25 participants during four, 20-minute conditions; resting, PlayStation 2 Madden NFL Football 2011, Nintendo Wii-Sports Boxing and Nintendo Wii Madden NFL Football 2011. Each condition was divided into two positional conditions (10 minutes seated, 10 minutes standing) and each participant indicated their positional preference after each 20-minute condition. Standing VO2 (4.4 ± 0.2 ml • kg-1 • min-1 PS2, 4.6 ± 0.1 ml • kg-1 • min-1 Wii Madden, 6.8 ± 0.3 ml • kg-1 • min-1Wii Boxing) was significantly (p ≤ 0.001) greater than seated VO2 (4.0 ± 0.1 ml • kg-1 • min-1 PS2, 4.2 ± 0.1 ml • kg-1 • min-1 Wii Madden, 6.1 ± 0.3 ml • kg-1 • min-1Wii Boxing) for each gaming condition. Participants preferred (p ≤ 0.001) to sit for all gaming conditions except Wii Boxing. Playing video games while standing increases VO2 to a greater extent than playing the same games in a seated position. Standing was only preferred for the most physiologically challenging game, Wii Boxing. Gaming position should be considered when assessing the physiologic and behavioral outcomes of playing video games.

  11. Prediction of induced vibrations in stall

    Energy Technology Data Exchange (ETDEWEB)

    Thirstrup Petersen, J.; Thomsen, K.; Aagaard Madsen, H. [Risoe National Lab., Wind Energy and Atmospheric Physics Dept., Roskilde (Denmark)

    1999-03-01

    The main results from recent research in stall induced vibrations are presented. The focus is on the edgewise blade vibrations, which during the last decade have turned out to be a potential threat against the stable operation of stall regulated wind turbines and a fact, which must be dealt with by the designer. The basic physical explanation for the phenomenon and examples of design precaution, which can be taken, are presented. (au)

  12. Impact of a classroom standing desk intervention on daily objectively measured sedentary behavior and physical activity in youth.

    Science.gov (United States)

    Silva, Danilo R; Minderico, Cláudia S; Pinto, Fernando; Collings, Paul J; Cyrino, Edilson S; Sardinha, Luís B

    2018-02-03

    We investigated the impact of a standing desk intervention on daily objectively monitored sedentary behavior and physical activity in 6th grade school students. Cluster non-randomised controlled trial. Two classes (intervention students: n=22 [aged 11.8±0.4years]; control students: n=27 [11.6±0.5years]) from a public school in Lisbon were selected. The intervention involved replacing traditional seated classroom desks for standing desks, for a total duration of 16 weeks, in addition to performing teacher training and holding education/motivation sessions with students and parents. Sedentary behavior (ActivPAL inclinometer) and physical activity (Actigraph GT3X+ accelerometer) were measured for seven days immediately before and after the intervention. There were no differences in baseline behaviors between intervention and control groups (p>0.05). At follow-up (16 weeks), it was observed that the intervention group had decreased time spent sitting (total week: -6.8% and at school: -13.0% relative to baseline) and increased standing (total week: 16.5% and at school: 31.0%) based on inclinometer values (p-value for interaction group*time <0.05). No significant differences in activity outcomes were observed outside school time (week or weekend) between groups. We conclude that a 16 week classroom standing desk intervention successfully reduced sitting time and increase standing time at school, with no observed compensatory effects outside of school time. Copyright © 2018 Sports Medicine Australia. Published by Elsevier Ltd. All rights reserved.

  13. High-Speed Experiments on Combustion-Powered Actuation for Dynamic Stall Suppression

    Science.gov (United States)

    Matalanis, Claude; Bowles, Patrick; Lorber, Peter; Crittenden, Thomas; Glezer, Ari; Schaeffler, Norman; Min, Byung-Young; Jee, Solkeun; Kuczek, Andrzej; Wake, Brian

    2016-01-01

    This work documents high-speed wind tunnel experiments conducted on a pitching airfoil equipped with an array of combustion-powered actuators (COMPACT). The main objective of these experiments was to demonstrate the stall-suppression capability of COMPACT on a high-lift rotorcraft airfoil, the VR-12, at relevant Mach numbers. Through dynamic pressure measurements at the airfoil surface it was shown that COMPACT can positively affect the stall behavior of the VR-12 at Mach numbers up to 0.4. Static airfoil results demonstrated 25% and 50% increases in post-stall lift at Mach numbers of 0.4 and 0.3, respectively. Deep dynamic stall results showed cycle-averaged lift coefficient increases up to 11% at Mach 0.4. Furthermore, it was shown that these benefits could be achieved with relatively few pulses during down-stroke and with no need to pre-anticipate the stall event. The flow mechanisms responsible for stall suppression were investigated using particle image velocimetry.

  14. Internal Flow of a High Specific-Speed Diagonal-Flow Fan (Rotor Outlet Flow Fields with Rotating Stall

    Directory of Open Access Journals (Sweden)

    Norimasa Shiomi

    2003-01-01

    Full Text Available We carried out investigations for the purpose of clarifying the rotor outlet flow fields with rotating stall cell in a diagonal-flow fan. The test fan was a high–specific-speed (ns=1620 type of diagonal-flow fan that had 6 rotor blades and 11 stator blades. It has been shown that the number of the stall cell is 1, and its propagating speed is approximately 80% of its rotor speed, although little has been known about the behavior of the stall cell because a flow field with a rotating stall cell is essentially unsteady. In order to capture the behavior of the stall cell at the rotor outlet flow fields, hot-wire surveys were performed using a single-slant hotwire probe. The data obtained by these surveys were processed by means of a double phase-locked averaging technique, which enabled us to capture the flow field with the rotating stall cell in the reference coordinate system fixed to the rotor. As a result, time-dependent ensemble averages of the three-dimensional velocity components at the rotor outlet flow fields were obtained. The behavior of the stall cell was shown for each velocity component, and the flow patterns on the meridional planes were illustrated.

  15. Plasma-based Compressor Stall Control

    Science.gov (United States)

    McGowan, Ryan; Corke, Thomas

    2017-11-01

    The use of dielectric barrier discharge (DBD) plasma actuator casing treatment to prevent or delay stall inception in an axial fan is examined. The actuators are powered by a pulsed-DC waveform which induces a larger peak velocity than a purely AC waveform such as a sine or sawtooth wave. With this system, a high-voltage DC source is supplied to both electrodes, remaining constant in time for the exposed electrode. Meanwhile, the covered electrode is periodically grounded for several microseconds and allowed to rise back to the source DC level. To test the actuators' ability to interact with and modify the formation of stall cells, a facility has been designed and constructed around nonconductive fan blades. The actuators are installed in the fan casing near the blade tips. The instrumentation allows for the measurement of rotating pressure disturbances (traveling stall cells) in this tip gap region as well as fan performance characteristics including pressure rise and flow rate. The casing plasma actuation is found to reduce the correlation of the rotating stall cells, thereby extending the stall margin of the fan. Various azimuthal arrangements of the plasma actuator casing treatment is explored, as well as input voltage levels to the actuator to determine optimum conditions. NASA SBIR Contract NNX14CC12C.

  16. The relevance of the dynamic stall effect for transient fault operations of active-stall wind turbines

    Energy Technology Data Exchange (ETDEWEB)

    Jauch, Clemens; Soerensen, Poul; Jensen, Birgitte Bak

    2005-06-15

    This article describes a methodology to quantify the influence of dynamic stall on transient fault operations of active-stall turbines. The model of the dynamic stall effect is introduced briefly. The behaviour of the dynamic stall model during a transient fault operation is described mathematically, and from this its effect quantified. Two quantities are chosen to describe the influence of the dynamic stall effect: one is active power and the other is time delay. Subsequently a transient fault scenario is simulated with and without the dynamic stall effect and the differences discussed. From this comparison, the conclusion is drawn that the dynamic stall effect has some influence on the post-fault behaviour of the wind turbine, and it is hence suggested that the dynamic stall effect is considered if an active-stall wind turbine is to be modelled realistically. (Author)

  17. Reversible swelling-shrinking behavior of hydrogen-bonded free-standing thin film stabilized by catechol reaction.

    Science.gov (United States)

    Sun, Jiaxing; Su, Chao; Zhang, Xuejian; Yin, Wenjing; Xu, Jian; Yang, Shuguang

    2015-05-12

    Dopamine-modified poly(acrylic acid) (PAA-dopa) and poly(vinylpyrrolidone) (PVPON) was layer-by-layer (LbL) assembled to prepare thin film based on hydrogen bonding. The carboxylic group of acrylic acid and the phenolic hydroxyl group of dopamine can both act as hydrogen bond donors. The critical assembly and the critical disintegration pH values of PVPON/PAA-dopa film are enhanced compared with PVPON/PAA film. The hydrogen-bonded PVPON/PAA-dopa thin film can be cross-linked via catechol chemistry of dopamine. After cross-linking, the film can be exfoliated from the substrate in alkaline solution to get a free-standing film. Moreover, by tuning the pH value, deprotonation and protonation of PAA will make the hydrogen bond in the film break and reconstruct, which induces that the free-standing film has a reversible swelling-shrinking behavior.

  18. Load prediction of stall regulated wind turbines

    Energy Technology Data Exchange (ETDEWEB)

    Bjoerck, A.; Dahlberg, J.Aa. [Aeronautical Research Inst. of Sweden, Bromma (Sweden); Carlen, I. [Chalmers Univ. of Technology, Goeteborg (Sweden). Div. of Marine Structural Engineering; Ganander, H. [Teknikgruppen AB, Sollentua (Sweden)

    1996-12-01

    Measurements of blade loads on a turbine situated in a small wind farm shows that the highest blade loads occur during operation close to the peak power i.e. when the turbine operates in the stall region. In this study the extensive experimental data base has been utilised to compare loads in selected campaigns with corresponding load predictions. The predictions are based on time domain simulations of the wind turbine structure, performed by the aeroelastic code VIDYN. In the calculations a model were adopted in order to include the effects of dynamic stall. This paper describes the work carried out so far within the project and key results. 5 refs, 10 figs

  19. Dynamic stall and 3D effects

    Energy Technology Data Exchange (ETDEWEB)

    Bjoerck, A.; Thor, S.E. [Aeronautical Research Inst. of Sweden, Bromma (Sweden)

    1996-12-01

    The JOULE II project `Dynamic stall and 3D effects` started in January 1994 and was completed in September 1995. The objective of the project has been to increase the understanding of the three-dimensional and unsteady aerodynamics of stall controlled HAWT`s. The objectives have also been to develop `engineering models` suitable for inclusion into aero-elastic codes. The project included the participation of 13 parties within Europe. This paper describes an overview of the work carried out within the project and key results. 3 refs, 4 figs

  20. Education stalls and subsequent stalls in African fertility: A descriptive overview

    Directory of Open Access Journals (Sweden)

    Anne Goujon

    2015-12-01

    Full Text Available Background: Recent stalls in fertility decline have been observed in a few countries in sub-Saharan Africa, and so far no plausible common reason has been identified in the literature. This paper develops the hypothesis that these fertility stalls could be associated with stalls in the progress of education among the women of the relevant cohorts, possibly resulting partly from the Structural Adjustment Programs (SAPs of the 1980s. Methods: We descriptively link the change in the education composition of successive cohorts of young women in sub-Saharan Africa and the recent fertility stalls. We use reconstructed data on population by age, gender, and level of education from www.wittgenstein centre.org/dataexplorer, and fertility rates from the United Nations. Results: In most sub-Saharan African countries, we observe that the same countries that had fertility stalls had a stall in the progress of education, particularly for young women who were of primary school age during the 1980s, when most of the countries were under structural adjustment. Conversely, stalls in fertility are less common in countries that did not have an education stall, possibly in relation to SAPs. Conclusions: The results point to the possibility of a link between the recent fertility stalls and discontinuities in the improvement of the education of the relevant cohorts, which in turn could be related to the SAPs in the 1980s. This descriptive finding now needs to be corroborated through more detailed cohort-specific fertility analysis. If the education-fertility link can be further established, it will have important implications for the projections of population growth in affected countries.

  1. Dynamic behavior of PEM FCPPs under various load conditions and voltage stability analysis for stand-alone residential applications

    Science.gov (United States)

    Uzunoglu, M.; Onar, O. C.; Alam, M. S.

    In this paper, dynamic behavior and performance of a fuel cell power plant (FCPP) which operates in parallel with a battery bank is tested under classified load conditions, such as mostly resistive, mostly inductive, resistive-inductive and non-linear loads. Thereafter, voltage stability analysis is performed using the dynamic response of the FCPP for stand-alone residential applications. Simulation results are obtained using the MATLAB ® and Simulink ® software packages, based on the mathematical and dynamic electrical models of the system. Using the experimental results, a validated model has been realized and voltage stability analysis is performed through this model.

  2. 16 CFR 1505.50 - Stalled motor testing.

    Science.gov (United States)

    2010-01-01

    ... 16 Commercial Practices 2 2010-01-01 2010-01-01 false Stalled motor testing. 1505.50 Section 1505... USE BY CHILDREN Policies and Interpretations § 1505.50 Stalled motor testing. (a) § 1505.6(e)(4)(ii) requires that a motor-operated toy be tested with the motor stalled if the construction of the toy is such...

  3. Post-spill behavior in an Oil Contaminated Mangrove Stand Avicennia Marina (Forssk.) Vierh in UAE

    International Nuclear Information System (INIS)

    Youssef, T.; El-Amry, M.; Youssef, A.

    2000-01-01

    The effect of post-spill defoliation and the subsequent readjustment in resource allocation was investigated in relation to individual reproductive fitness of the monotypic mangrove stands Avicennia mariana in Umm Al-Qwain Bay, northeastern United Arab Emirates. The effects of persistence of high levels of oil hydrocarbons in the sediments after the spill on propagule dispersal, seedling recruitment, and anomalous vegetative growth forms were also studied. Growth and physiological performance of the new individuals produced from polluted and unpolluted vegetations were compared under glasshouse conditions. Vegetative recovery of oil mangrove stands from post-spill massive defoliation had a negative effect on all stages of plant reproductive events including flowering, fruiting and propagule dispersal. Persistence of toxic levels of oil hydrocarbons in the substrate has further reduced the possibility of successful establishment of new generation in the contaminated site. A significant correlation exists between the levels of hydrocarbons in the sediments and the degree of anomalies in shoot growth of seedlings (r=0.862) and the newly growing pneumataphores (r=0.827). Improving substrate condition by reducing levels of toxic hydrocarbons would increase the chance for better recruitment and performance of the new generation of seedlings. Active rehabilitation processes at the site may enhance the site productivity and minimize time for natural recovery. (author)

  4. Simulation model of an active stall wind turbine controller

    Energy Technology Data Exchange (ETDEWEB)

    Jauch, C.; Hansen, A.D.; Soerensen, P. [Risoe National Lab., Wind Energy Dept., Rosilde (Denmark); Blaabjerg, F. [Aalborg Univ., Inst. of Energy Technology (Denmark)

    2004-07-01

    This paper describes an active stall wind turbine controller. The objective is to develop a general model of an active stall controller in order to simulate the operation of grid connected active stall wind turbines. The active stall turbine concept and its control strategies are presented and evaluated on the basis of simulations. The presented controller is described for continuous operation under all wind speeds from start-up wind speed to shut doven wind speed. Due to its parametric implementation it is general i.e. it can represent different active stall wind turbine controllers and can be implemented in different simulation tools. (au)

  5. Numerical Investigations of Dynamic Stall Control

    Directory of Open Access Journals (Sweden)

    Florin FRUNZULICA

    2014-04-01

    Full Text Available In this paper we investigated numerically the dynamic stall phenomenon and the possibilities to control it, with application to vertical axis wind turbines (for urban users. The Phenomenon appear at low tip speed ratio (TSR<4 and it has a great impact on structural integrity of the wind turbine and power performances. For this reason we performed a computational study of dynamic stall around NACA 0012 airfoil in pitching motion at relative low Reynolds number (105. Also, we performed the same analysis for four flow control methods: two passive (Gurney flap and slot and two active (blowing jet on the rounded trailing edge and synthetic jet periodically activated. The Results are compared to those of an existing experimental case test.

  6. Dynamic Stall Control Using Plasma Actuators

    Science.gov (United States)

    Webb, Nathan; Singhal, Achal; Castaneda, David; Samimy, Mo

    2017-11-01

    Dynamic stall occurs in many applications, including sharp maneuvers of fixed wing aircraft, wind turbines, and rotorcraft and produces large unsteady aerodynamic loads that can lead to flutter and mechanical failure. This work uses flow control to reduce the unsteady loads by excitation of instabilities in the shear layer over the separated region using nanosecond pulse driven dielectric barrier discharge (NS-DBD) plasma actuators. These actuators have been shown to effectively delay or mitigate static stall. A wide range of flow parameters were explored in the current work: Reynolds number (Re = 167,000 to 500,000), reduced frequency (k = 0.025 to 0.075), and excitation Strouhal number (Ste = 0 to 10). Based on the results, three major conclusions were drawn: (a) Low Strouhal number excitation (Ste eliminated the dynamic stall vortex (DSV), thereby dramatically reducing the unsteady loading. The decrease in the strength of the DSV is achieved by the formation of shear layer coherent structures that bleed the leading-edge vorticity prior to the ejection of the DSV.

  7. Self-standing elastomeric composites based on lithium ferrites and their dielectric behavior

    Energy Technology Data Exchange (ETDEWEB)

    Soreto Teixeira, S.; Graça, M. P. F.; Costa, L. C. [I3N and Physics Department, University of Aveiro, 3810-193 Aveiro (Portugal); Dionisio, M. [REQUIMTE, Departamento de Química, Faculdade de Ciências e Tecnologia, Universidade Nova de Lisboa, 2829-516 Caparica (Portugal); Ilcíkova, M.; Mosnacek, J.; Spitalsky, Z. [Polymer Institute, Slovak Academy of Sciences, Dúbravská cesta 9, Bratislava (Slovakia); Krupa, I. [Polymer Institute, Slovak Academy of Sciences, Dúbravská cesta 9, Bratislava (Slovakia); Center for Advanced Materials, Qatar University, P.O. Box 2713, Doha (Qatar)

    2014-12-14

    Lithium ferrite (LiFe{sub 5}O{sub 8}) is an attractive material for technological applications due to its physical properties, which are significantly dependent on the preparation method and raw materials. In this work, LiFe{sub 5}O{sub 8} crystallites were obtained by controlled heat-treatment process at 1100 °C, of a homogeneous mixture of Li{sub 2}O-Fe{sub 2}O{sub 3} powders, prepared by wet ball-milling and using lithium and iron nitrates as raw materials. The main goal was the preparation of a flexible and self-standing tick composite film by embedding lithium ferrite particles in a polymeric matrix, taking advantage of the good mechanical properties of the polymer and of the electrical and dielectric properties of the ferrite. The selected polymer matrix was styrene-b-isoprene-b-styrene copolymer. To prepare the composites, the lithium ferrite particles were chemically modified in order to functionalize their surface. To analyse the influence of the particles surface modification, different composites were made, with modified and unmodified particles. The structure of the obtained composites was studied by FTIR, XRD, TGA, and DSC techniques. The dielectric properties were analysed, in the frequency range between 10 Hz and 1 MHz and in function of temperature in the range between −73 °C and 127 °C. These properties were related with the structure and concentration of the particles in the matrix network. The composites with the modified particles present higher dielectric constant, maintaining values of loss tangent sufficiently low (<10{sup −2}) that can be considered interesting for technological applications.

  8. Self-standing elastomeric composites based on lithium ferrites and their dielectric behavior

    Science.gov (United States)

    Soreto Teixeira, S.; Graça, M. P. F.; Dionisio, M.; Ilcíkova, M.; Mosnacek, J.; Spitalsky, Z.; Krupa, I.; Costa, L. C.

    2014-12-01

    Lithium ferrite (LiFe5O8) is an attractive material for technological applications due to its physical properties, which are significantly dependent on the preparation method and raw materials. In this work, LiFe5O8 crystallites were obtained by controlled heat-treatment process at 1100 °C, of a homogeneous mixture of Li2O-Fe2O3 powders, prepared by wet ball-milling and using lithium and iron nitrates as raw materials. The main goal was the preparation of a flexible and self-standing tick composite film by embedding lithium ferrite particles in a polymeric matrix, taking advantage of the good mechanical properties of the polymer and of the electrical and dielectric properties of the ferrite. The selected polymer matrix was styrene-b-isoprene-b-styrene copolymer. To prepare the composites, the lithium ferrite particles were chemically modified in order to functionalize their surface. To analyse the influence of the particles surface modification, different composites were made, with modified and unmodified particles. The structure of the obtained composites was studied by FTIR, XRD, TGA, and DSC techniques. The dielectric properties were analysed, in the frequency range between 10 Hz and 1 MHz and in function of temperature in the range between -73 °C and 127 °C. These properties were related with the structure and concentration of the particles in the matrix network. The composites with the modified particles present higher dielectric constant, maintaining values of loss tangent sufficiently low (<10-2) that can be considered interesting for technological applications.

  9. Stalling HIV through social marketing: prospects in Pakistan.

    Science.gov (United States)

    Husain, Sara; Shaikh, Babar T

    2005-07-01

    Over the last two decades HIV/AIDS has evolved from a series of interesting case-reports to a growing epidemic that threatens the entire world. It is feared to cause devastation among large pockets of populations and may roll back more than thirty years of public health achievements. This killer disease has been more amenable to behavioral change than by provision of curative services and attempts are being made to educate the public about this threat. Various techniques of promotion have been tried through out the world including television dramas/soaps, mass media and school curricula. Social marketing is an evolving strategy used to influence human behavior and choices. By using the principles of marketing and promoting behavior as a product, social marketers attempt to understand the dynamics of human behaviour and devise messages and products to change, modify, accept or reject unsafe behaviors or practices. Thus, social marketers provide an effective force to combat the spread of HIV and may serve to be invaluable allies in health promotion efforts. In a complex and diversified cultural milieu of Pakistan, social marketing can have a significant impact on health determinants and the conditions that will facilitate the adoption of health-oriented behaviors and practices. This paper gives an account of the elements needed for the success of a health promotion strategy adopted in a developing country and makes a case for social marketing to be adopted as the lead strategy for stalling HIV/AIDS in Pakistan.

  10. Modeling how substitution of sedentary behavior with standing or physical activity is associated with health-related quality of life in colorectal cancer survivors

    OpenAIRE

    van Roekel, Eline H.; Bours, Martijn J. L.; Breedveld-Peters, Jos? J. L.; Willems, Paul J. B.; Meijer, Kenneth; Kant, IJmert; van den Brandt, Piet A.; Beets, Geerard L.; Sanduleanu, Silvia; Weijenberg, Matty P.

    2016-01-01

    Purpose Previous research indicates that sedentary behavior is unfavorably associated with health-related quality of life (HRQoL) of colorectal cancer (CRC) survivors. Using isotemporal substitution modeling, we studied how substituting sedentary behavior with standing or physical activity was associated with HRQoL in CRC survivors, 2?10?years post-diagnosis. Methods A cross-sectional study was conducted in stage I?III CRC survivors (n?=?145) diagnosed at Maastricht University Medical Center+...

  11. 14 CFR 23.201 - Wings level stall.

    Science.gov (United States)

    2010-01-01

    ... 14 Aeronautics and Space 1 2010-01-01 2010-01-01 false Wings level stall. 23.201 Section 23.201 Aeronautics and Space FEDERAL AVIATION ADMINISTRATION, DEPARTMENT OF TRANSPORTATION AIRCRAFT AIRWORTHINESS.... Starting from a speed at least 10 knots above the stall speed, the elevator control must be pulled back so...

  12. 14 CFR 33.65 - Surge and stall characteristics.

    Science.gov (United States)

    2010-01-01

    ... 14 Aeronautics and Space 1 2010-01-01 2010-01-01 false Surge and stall characteristics. 33.65 Section 33.65 Aeronautics and Space FEDERAL AVIATION ADMINISTRATION, DEPARTMENT OF TRANSPORTATION AIRCRAFT... stall characteristics. When the engine is operated in accordance with operating instructions required by...

  13. Compressible dynamic stall vorticity flux control using a dynamic ...

    Indian Academy of Sciences (India)

    management of its unsteady vorticity using a variable droop leading edge (VDLE) airfoil. Through ... the pressure gradient term for the dynamic stall conditions encountered by a helicopter-rotor retreating blade. Thus ... This paper discusses control of compressible dynamic stall using the novel idea of variable droop leading ...

  14. Theoretical analysis of transcription process with polymerase stalling

    Science.gov (United States)

    Li, Jingwei; Zhang, Yunxin

    2015-05-01

    Experimental evidence shows that in gene transcription RNA polymerase has the possibility to be stalled at a certain position of the transcription template. This may be due to the template damage or protein barriers. Once stalled, polymerase may backtrack along the template to the previous nucleotide to wait for the repair of the damaged site, simply bypass the barrier or damaged site and consequently synthesize an incorrect messenger RNA, or degrade and detach from the template. Thus, the effective transcription rate (the rate to synthesize correct product mRNA) and the transcription effectiveness (the ratio of the effective transcription rate to the effective transcription initiation rate) are both influenced by polymerase stalling events. So far, no theoretical model has been given to discuss the gene transcription process including polymerase stalling. In this study, based on the totally asymmetric simple exclusion process, the transcription process including polymerase stalling is analyzed theoretically. The dependence of the effective transcription rate, effective transcription initiation rate, and transcription effectiveness on the transcription initiation rate, termination rate, as well as the backtracking rate, bypass rate, and detachment (degradation) rate when stalling, are discussed in detail. The results showed that backtracking restart after polymerase stalling is an ideal mechanism to increase both the effective transcription rate and the transcription effectiveness. Without backtracking, detachment of stalled polymerase can also help to increase the effective transcription rate and transcription effectiveness. Generally, the increase of the bypass rate of the stalled polymerase will lead to the decrease of the effective transcription rate and transcription effectiveness. However, when both detachment rate and backtracking rate of the stalled polymerase vanish, the effective transcription rate may also be increased by the bypass mechanism.

  15. Effect of stall design on dairy calf transition to voluntary feeding on an automatic milk feeder after introduction to group housing.

    Science.gov (United States)

    Wilson, Tanya R; LeBlanc, Stephen J; DeVries, Trevor J; Haley, Derek B

    2018-03-14

    Automatic milk feeders (AMF) for young dairy calves are widely used in the dairy industry. These feeders are thought to have benefits for calf health and welfare and may reduce labor required for feeding; however, little is known about how calves adapt to feeding with AMF. The objective of this study was to observe the effects of feeding stall design on calves learning to use the AMF. The hypothesis was that solid side stalls, compared with steel bar stalls, would result in a longer latency to approach and feed from the AMF without assistance. A total of 147 Holstein calves (80 male and 67 female) were enrolled at 4 d of age, introduced to a group pen, and, at the same time, trained on an AMF. For training, calves were allowed to suck on the trainer's fingers and guided to the teat. Calves were allocated to 1 of 2 stall designs at the pen level, depending on which treatment cohort they were born into, either with steel bar stall walls (n = 46 male, 34 female calves) or with solid side stall walls (n = 34 male, 33 female calves). For 72 h after introductory training on the AMF, data from the feeders were collected and calf behavior was monitored by video. Outcomes measured included latency to first voluntary visit to the feeder and to first feeding, time spent in the feeder, amount of milk consumed over 72 h, number of retraining sessions required (retrained if linear regression models or a Poisson model for the outcome of retraining. For certain outcomes the effects of stall design interacted with difficulty of training (willingness to enter feeder and drink); for the 38% of calves that were scored as moderately difficult to train on a scale of easy, moderate, or difficult, treatment (stall design) differences were detected. These calves took 2× longer to lick or bite toward the nipple, 2× longer to first voluntarily feeding, and consumed less milk over 72 h following training when trained on the steel bar stall design. These results suggest simple features of a

  16. Drive Stands

    Data.gov (United States)

    Federal Laboratory Consortium — The Electrical Systems Laboratory (ESL)houses numerous electrically driven drive stands. A drive stand consists of an electric motor driving a gearbox and a mounting...

  17. Dynamic Stall in Pitching Airfoils: Aerodynamic Damping and Compressibility Effects

    Science.gov (United States)

    Corke, Thomas C.; Thomas, Flint O.

    2015-01-01

    Dynamic stall is an incredibly rich fluid dynamics problem that manifests itself on an airfoil during rapid, transient motion in which the angle of incidence surpasses the static stall limit. It is an important element of many manmade and natural flyers, including helicopters and supermaneuverable aircraft, and low-Reynolds number flapping-wing birds and insects. The fluid dynamic attributes that accompany dynamic stall include an eruption of vorticity that organizes into a well-defined dynamic stall vortex and massive excursions in aerodynamic loads that can couple with the airfoil structural dynamics. The dynamic stall process is highly sensitive to surface roughness that can influence turbulent transition and to local compressibility effects that occur at free-stream Mach numbers that are otherwise incompressible. Under some conditions, dynamic stall can result in negative aerodynamic damping that leads to limit-cycle growth of structural vibrations and rapid mechanical failure. The mechanisms leading to negative damping have been a principal interest of recent experiments and analysis. Computational fluid dynamic simulations and low-order models have not been good predictors so far. Large-eddy simulation could be a viable approach although it remains computationally intensive. The topic is technologically important owing to the desire to develop next-generation rotorcraft that employ adaptive rotor dynamic stall control.

  18. Near Stall Flow Analysis in the Transonic Fan of the RTA Propulsion System

    Science.gov (United States)

    Hah, Chunill

    2010-01-01

    Turbine-based propulsion systems for access to space have been investigated at NASA Glenn Research center. A ground demonstrator engine for validation testing has been developed as a part of the program. The demonstrator, the Revolutionary Turbine Accelerator (RTA-1), is a variable cycle turbofan ramjet designed to transition from an augmented turbofan to a ramjet that produces the thrust required to accelerate the vehicle to Mach 4. The RTA-1 is designed to accommodate a large variation in bypass ratio from sea level static to Mach 4 flight condition. A key component of this engine is a new fan stage that accommodates these large variations in bypass ratio and flow ranges. In the present study, unsteady flow behavior in the fan of the RTA-1 is studied in detail with large eddy simulation (LES) and the numerical results are compared with measured data. During the experimental study of the fan stage, humming sound was detected at 100 % speed near stall operation. The main purpose of the study is to investigate details of the unsteady flow behavior at near stall operation and to identify a possible cause of the hum. The large eddy simulation of the current flow field reproduces main features of the measured flow very well. The LES simulation indicates that non-synchronous flow instability develops as the fan operates toward the stall limit. The FFT analysis of the calculated wall pressure shows that the rotating flow instability has the characteristic frequency that is about 50% of the blade passing frequency.

  19. A Beddoes-Leishman type dynamic stall model in state-space and indicial formulations

    DEFF Research Database (Denmark)

    Hansen, M.H.; Gaunaa, Mac; Aagaard Madsen, Helge

    2004-01-01

    This report contains a description of a Beddoes-Leishman type dynamic stall model in both a state-space and an indicial function formulation. The model predicts the unsteady aerodynamic forces and moment on an airfoil section undergoing arbitrary motionin heave, lead-lag, and pitch. The model...... features, such as overshoot of the lift, in the stall region. The linearized model is shown to give identicalresults to the full model for small amplitude oscillations. Furthermore, it is shown that the response of finite thichkness airfoils can be reproduced to a high accuracy by the use of specific...... is carried out by comparing the response of the model with inviscid solutions and observing the general behavior of the model using known airfoil data as input. Theproposed dynamic model gives results identical to inviscid solutions within the attached-flow region; and it exhibits the expected dynamic...

  20. Flap motion of helicopter rotors with novel, dynamic stall model

    Directory of Open Access Journals (Sweden)

    Han Wei

    2016-01-01

    Full Text Available In this paper, a nonlinear flapping equation for large inflow angles and flap angles is established by analyzing the aerodynamics of helicopter blade elements. In order to obtain a generalized flap equation, the Snel stall model was first applied to determine the lift coefficient of the helicopter rotor. A simulation experiment for specific airfoils was then conducted to verify the effectiveness of the Snel stall model as it applies to helicopters. Results show that the model requires no extraneous parameters compared to the traditional stall model and is highly accurate and practically applicable. Based on the model, the relationship between the flapping angle and the angle of attack was analyzed, as well as the advance ratio under the dynamic stall state.

  1. HAWT dynamic stall response asymmetries under yawed flow conditions

    Energy Technology Data Exchange (ETDEWEB)

    Schreck, S.; Robinson, M.; Hand, M.; Simms, D.

    2000-02-28

    Horizontal axis wind turbines can experience significant time varying aerodynamic loads, potentially causing adverse effects on structures, mechanical components, and power production. As designers attempt lighter and more flexible wind energy machines, greater accuracy and robustness will become even more critical in future aerodynamics models. Aerodynamics modeling advances, in turn, will rely on more thorough comprehension of the three-dimensional, unsteady, vortical flows that dominate wind turbine blade aerodynamics under high load conditions. To experimentally characterize these flows, turbine blade surface pressures were acquired at multiple span locations via the NREL Phase IV Unsteady Aerodynamics Experiment. Surface pressures and associated normal force histories were used to characterize dynamic stall vortex kinematics and normal force amplification. Dynamic stall vortices and normal force amplification were confirmed to occur in response to angle of attack excursions above the static stall threshold. Stall vortices occupied approximately one-half of the blade span and persisted for nearly one-fourth of the blade rotation cycle. Stall vortex convection varied along the blade, resulting in dramatic deformation of the vortex. Presence and deformation of the dynamic stall vortex produced corresponding amplification of normal forces. Analyses revealed consistent alterations to vortex kinematics in response to changes in reduced frequency, span location, and yaw error. Finally, vortex structures and kinematics not previously documented for wind turbine blades were isolated.

  2. The Implications of Big-Five Standing for the Distribution of Trait Manifestation in Behavior: Fifteen Experience-Sampling Studies and a Meta-Analysis

    Science.gov (United States)

    Fleeson, William; Gallagher, M. Patrick

    2009-01-01

    One of the fundamental questions in personality psychology is whether and how strongly trait standing relates to the traits that people actually manifest in their behavior, when faced with real pressures and real consequences of their actions. One reason this question is fundamental is the common belief that traits do not predict how individuals behave, which leads to the reasonable conclusion that traits are not important to study. However, this conclusion is surprising given that there is almost no data on the ability of traits to predict distributions of naturally occurring, representative behaviors of individuals (and that there are many studies showing that traits do indeed predict specific behaviors). This paper describes a meta-analysis of 15 experience-sampling studies, conducted over the course of eight years, amassing over 20,000 reports of trait manifestation in behavior. Participants reported traits on typical self-report questionnaires, then described their current behavior multiple times per day for several days, as the behavior was occurring. Results showed that traits, contrary to expectations, were strongly predictive of individual differences in trait manifestation in behavior, predicting average levels with correlations between .42 and .56 (approaching .60 for stringently restricted studies). Several other ways of summarizing trait manifestation in behavior were also predicted from traits. These studies provide evidence that traits are powerful predictors of actual manifestation of traits in behavior. PMID:19968421

  3. Is Social Licence A Licence To Stall?

    Directory of Open Access Journals (Sweden)

    Mark Lowey

    2016-03-01

    Full Text Available The School of Public Policy at the University of Calgary organized a one-day symposium on Oct. 8, 2014 in Calgary, as part of the School’s TransCanada Corporation Energy Policy and Regulatory Frameworks Program. The symposium was titled “Is Social License a License to Stall?” Held at the Hotel Arts, the event attracted a full-capacity audience of about 110 people, including representatives from industry, government and environmental non-government organizations. The symposium included four moderated panel sessions and a keynote speaker at lunch. The School of Public Policy set the framework for discussion at the Calgary symposium with the following description: Canada’s regulators act in the public interest to review energy and infrastructure project applications. Regulators are guided by procedural fairness and follow a transparent application, review and hearing process with data filings and sworn testimony. But that’s changing. “Social license” is a relatively new term, which some interests are using to create a different standard for the approval of projects — especially energy projects. According to social license advocates, projects must meet often ill-defined requirements set up by non-governmental organizations, local residents or other interests — a new hurdle for project approval, but without the rigour and rule of law of a regulator. Is social license a meaningful addition to the regulatory process, or is it being used as a constantly moving goal-post designed to slow down regulatory processes, delay project implementation, frustrate energy infrastructure expansion and even enrich those advocates who promote it as a new model? This paper summarises the discussion and the themes that emerged throughout the day. Most notably, panellists concluded that “social licence” is a real and significant issue that presents both an opportunity and a problem, not only for regulators but for all parties involved in the

  4. Where Do I Stand? Examining the Effects of Leader-Member Exchange Social Comparison on Employee Work Behaviors

    Science.gov (United States)

    Vidyarthi, Prajya R.; Liden, Robert C.; Anand, Smriti; Erdogan, Berrin; Ghosh, Samiran

    2010-01-01

    Taking an approach integrating principles of leader-member exchange (LMX) differentiation with social comparison theory, we contend that subjective ratings by individuals of their LMX compared to the LMXs of coworkers (labeled LMX social comparison, or LMXSC) explain unique and meaningful variance in outcomes beyond LMX and the actual standing of…

  5. Comportamento ingestivo de vacas Jersey confinadas durante a fase inicial da lactação Ingestive behavior of Jersey cows in free stall at the beginning of lactation

    Directory of Open Access Journals (Sweden)

    Cintia Oliveira da Costa

    2003-04-01

    Full Text Available Este trabalho foi desenvolvido com o objetivo de caracterizar o comportamento ingestivo de vacas da raça Jersey durante duas épocas do ano (estações fria e quente e aos 30, 60 e 90 dias pós-parto. Os tempos diários gastos com ingestão, ruminação e descanso foram estimados a partir de observações visuais realizadas por um único observador bem treinado. Os registros das atividades comportamentais foram realizados a intervalos de 10 minutos, durante 24 horas por dia, cinco dias por período, totalizando 30 dias de observações. Os animais foram observados individualmente. Os tempos médios de ingestão e ruminação foram maiores na estação quente, comparados à estação fria e aos 30 dias pós-parto comparados aos 90 dias pós-parto, e associados com os efeitos positivos de temperatura, fotoperíodo e teor de fibra da silagem. O peso vivo decresceu até 30 dias pós-parto, apresentando recuperação aos 90 dias pós-parto. A produção de leite apresentou interação significativa entre época e período, com menor produção de leite aos 60 dias pós-parto em relação aos 30 e 90 dias pós-parto, principalmente na estação quente, fato parcialmente atribuído às mudanças na composição química da silagem. Concluiu-se que as vacas leiteiras modificaram seu comportamento ingestivo para se adaptarem às mudanças nutricionais, ambientais (efeito de época e anatômicas e fisiológicas (efeito do número de dias após o parto.This trial aimed to characterize the ingestive behavior of Jersey dairy cows during cool and warm seasons, and at 30, 60 and 90 days post-partum. Daily time spent eating, ruminating and idling was estimated through visual observations recorded by a well trained observer. Records were made intermittently, using 10 minutes interval during 24 hours, five days per period, totalizing 30 days of observations. Ingestive behavior was recorded for each individual animal. Daily eating and rumination times were larger

  6. Dynamic Stall Characteristics of Drooped Leading Edge Airfoils

    Science.gov (United States)

    Sankar, Lakshmi N.; Sahin, Mehmet; Gopal, Naveen

    2000-01-01

    Helicopters in high-speed forward flight usually experience large regions of dynamic stall over the retreating side of the rotor disk. The rapid variations in the lift and pitching moments associated with the stall process can result in vibratory loads, and can cause fatigue and failure of pitch links. In some instances, the large time lag between the aerodynamic forces and the blade motion can trigger stall flutter. A number of techniques for the alleviation of dynamic stall have been proposed and studied by researchers. Passive and active control techniques have both been explored. Passive techniques include the use of high solidity rotors that reduce the lift coefficients of individual blades, leading edge slots and leading edge slats. Active control techniques include steady and unsteady blowing, and dynamically deformable leading edge (DDLE) airfoils. Considerable amount of experimental and numerical data has been collected on the effectiveness of these concepts. One concept that has not received as much attention is the drooped-leading edge airfoil idea. It has been observed in wind tunnel studies and flight tests that drooped leading edge airfoils can have a milder dynamic stall, with a significantly milder load hysteresis. Drooped leading edge airfoils may not, however, be suitable at other conditions, e.g. in hover, or in transonic flow. Work needs to be done on the analysis and design of drooped leading edge airfoils for efficient operation in a variety of flight regimes (hover, dynamic stall, and transonic flow). One concept that is worthy of investigation is the dynamically drooping airfoil, where the leading edge shape is changed roughly once-per-rev to mitigate the dynamic stall.

  7. The Dynamics of SecM-Induced Translational Stalling

    Directory of Open Access Journals (Sweden)

    Albert Tsai

    2014-06-01

    Full Text Available SecM is an E. coli secretion monitor capable of stalling translation on the prokaryotic ribosome without cofactors. Biochemical and structural studies have demonstrated that the SecM nascent chain interacts with the 50S subunit exit tunnel to inhibit peptide bond formation. However, the timescales and pathways of stalling on an mRNA remain undefined. To provide a dynamic mechanism for stalling, we directly tracked the dynamics of elongation on ribosomes translating the SecM stall sequence (FSTPVWISQAQGIRAGP using single-molecule fluorescence techniques. Within 1 min, three peptide-ribosome interactions work cooperatively over the last five codons of the SecM sequence, leading to severely impaired elongation rates beginning from the terminal proline and lasting four codons. Our results suggest that stalling is tightly linked to the dynamics of elongation and underscore the roles that the exit tunnel and nascent chain play in controlling fundamental steps in translation.

  8. The dynamics of SecM-induced translational stalling.

    Science.gov (United States)

    Tsai, Albert; Kornberg, Guy; Johansson, Magnus; Chen, Jin; Puglisi, Joseph D

    2014-06-12

    SecM is an E. coli secretion monitor capable of stalling translation on the prokaryotic ribosome without cofactors. Biochemical and structural studies have demonstrated that the SecM nascent chain interacts with the 50S subunit exit tunnel to inhibit peptide bond formation. However, the timescales and pathways of stalling on an mRNA remain undefined. To provide a dynamic mechanism for stalling, we directly tracked the dynamics of elongation on ribosomes translating the SecM stall sequence (FSTPVWISQAQGIRAGP) using single-molecule fluorescence techniques. Within 1 min, three peptide-ribosome interactions work cooperatively over the last five codons of the SecM sequence, leading to severely impaired elongation rates beginning from the terminal proline and lasting four codons. Our results suggest that stalling is tightly linked to the dynamics of elongation and underscore the roles that the exit tunnel and nascent chain play in controlling fundamental steps in translation. Copyright © 2014 The Authors. Published by Elsevier Inc. All rights reserved.

  9. A Comparative Study of Three Methodologies for Modeling Dynamic Stall

    Science.gov (United States)

    Sankar, L.; Rhee, M.; Tung, C.; ZibiBailly, J.; LeBalleur, J. C.; Blaise, D.; Rouzaud, O.

    2002-01-01

    During the past two decades, there has been an increased reliance on the use of computational fluid dynamics methods for modeling rotors in high speed forward flight. Computational methods are being developed for modeling the shock induced loads on the advancing side, first-principles based modeling of the trailing wake evolution, and for retreating blade stall. The retreating blade dynamic stall problem has received particular attention, because the large variations in lift and pitching moments encountered in dynamic stall can lead to blade vibrations and pitch link fatigue. Restricting to aerodynamics, the numerical prediction of dynamic stall is still a complex and challenging CFD problem, that, even in two dimensions at low speed, gathers the major difficulties of aerodynamics, such as the grid resolution requirements for the viscous phenomena at leading-edge bubbles or in mixing-layers, the bias of the numerical viscosity, and the major difficulties of the physical modeling, such as the turbulence models, the transition models, whose both determinant influences, already present in static maximal-lift or stall computations, are emphasized by the dynamic aspect of the phenomena.

  10. Time Accurate Unsteady Simulation of the Stall Inception Process in the Compression System of a US Army Helicopter Gas Turbine Engine

    National Research Council Canada - National Science Library

    Hathaway, Michael D; Herrick, Greg; Chen, Jenping; Webster, Robert

    2004-01-01

    .... Improved understanding of the stall inception process and how stall control technologies mitigate such will provide compressors with increased tolerance to stall, thereby expanding the operational...

  11. Dynamics and Control of Three-Dimensional Perching Maneuver under Dynamic Stall Influence

    Science.gov (United States)

    Feroskhan, Mir Alikhan Bin Mohammad

    Perching is a type of aggressive maneuver performed by the class 'Aves' species to attain precision point landing with a generally short landing distance. Perching capability is desirable on unmanned aerial vehicles (UAVs) due to its efficient deceleration process that potentially expands the functionality and flight envelope of the aircraft. This dissertation extends the previous works on perching, which is mostly limited to two-dimensional (2D) cases, to its state-of-the-art threedimensional (3D) variety. This dissertation presents the aerodynamic modeling and optimization framework adopted to generate unprecedented variants of the 3D perching maneuver that include the sideslip perching trajectory, which ameliorates the existing 2D perching concept by eliminating the undesirable undershoot and reliance on gravity. The sideslip perching technique methodically utilizes the lateral and longitudinal drag mechanisms through consecutive phases of yawing and pitching-up motion. Since perching maneuver involves high rates of change in the angles of attack and large turn rates, introduction of three internal variables thus becomes necessary for addressing the influence of dynamic stall delay on the UAV's transient post-stall behavior. These variables are then integrated into a static nonlinear aerodynamic model, developed using empirical and analytical methods, and into an optimization framework that generates a trajectory of sideslip perching maneuver, acquiring over 70% velocity reduction. An impact study of the dynamic stall influence on the optimal perching trajectories suggests that consideration of dynamic stall delay is essential due to the significant discrepancies in the corresponding control inputs required. A comparative study between 2D and 3D perching is also conducted to examine the different drag mechanisms employed by 2D and 3D perching respectively. 3D perching is presented as a more efficient deceleration technique with respect to spatial costs and

  12. PTEN Regulates DNA Replication Progression and Stalled Fork Recovery

    Science.gov (United States)

    He, Jinxue; Kang, Xi; Yin, Yuxin; Chao, K.S. Clifford; Shen, Wen H.

    2015-01-01

    Faithful DNA replication is a cornerstone of genomic integrity. PTEN plays multiple roles in genome protection and tumor suppression. Here we report on the importance of PTEN in DNA replication. PTEN depletion leads to impairment of replication progression and stalled fork recovery, indicating an elevation of endogenous replication stress. Exogenous replication inhibition aggravates replication-originated DNA lesions without inducing S-phase arrest in cells lacking PTEN, representing replication stress tolerance. Our analysis reveals the physical association of PTEN with DNA replication forks and PTEN-dependent recruitment of Rad51. PTEN deletion results in Rad51 dissociation from replication forks. Stalled replication forks in Pten null cells can be reactivated by ectopic Rad51 or PTEN, the latter facilitating chromatin loading of Rad51. These data highlight the interplay of PTEN with Rad51 in promoting stalled fork restart. We propose that loss of PTEN may initiate a replication stress cascade that progressively deteriorates through the cell cycle. PMID:26158445

  13. Active Suppression of Rotating Stall Inception with Distributed Jet Actuation

    Directory of Open Access Journals (Sweden)

    Huu Duc Vo

    2007-01-01

    Full Text Available An analytical and experimental investigation of the effectiveness of full-span distributed jet actuation for active suppression of long length-scale rotating stall inception is carried out. Detailed modeling and experimental verification highlight the important effects of mass addition, discrete injectors, and feedback dynamics, which may be overlooked in preliminary theoretical studies of active control with jet injection. A model of the compression system incorporating nonideal injection and feedback dynamics is verified with forced response measurements to predict the right trends in the movement of the critical pole associated with the stall precursor. Active control experiments with proportional feedback control show that the predicted stall precursors are suppressed to give a 5.5% range extension in compressor flow coefficient. In addition, results suggest that the proposed model could be used to design a more sophisticated controller to further improve performance while reducing actuator bandwidth requirements.

  14. Stall Recovery Guidance Algorithms Based on Constrained Control Approaches

    Science.gov (United States)

    Stepanyan, Vahram; Krishnakumar, Kalmanje; Kaneshige, John; Acosta, Diana

    2016-01-01

    Aircraft loss-of-control, in particular approach to stall or fully developed stall, is a major factor contributing to aircraft safety risks, which emphasizes the need to develop algorithms that are capable of assisting the pilots to identify the problem and providing guidance to recover the aircraft. In this paper we present several stall recovery guidance algorithms, which are implemented in the background without interfering with flight control system and altering the pilot's actions. They are using input and state constrained control methods to generate guidance signals, which are provided to the pilot in the form of visual cues. It is the pilot's decision to follow these signals. The algorithms are validated in the pilot-in-the loop medium fidelity simulation experiment.

  15. "What you see depends on where you stand" exploring the relationship between leadership behavior and job type in health care.

    Science.gov (United States)

    Gover, Laura; Duxbury, Linda

    2013-01-01

    This chapter seeks to increase our understanding of health care employees' perceptions of effective and ineffective leadership behavior within their organization. Interviews were conducted with 59 employees working in a diversity of positions within the case study hospital. Interviewees were asked to cite behaviors of both an effective and an ineffective leader in their organization. They were also asked to clarify whether their example described the behavior of a formal or informal leader. Grounded theory data analysis techniques were used and findings were interpreting using existing leadership behavior theories. (1) There was a consistent link between effective leadership and relationally oriented behaviors. (2) Employees identified both formal and informal leadership within their hospital. (3) There were both similarities and differences with respect to the types of behaviors attributed to informal versus formal leaders. (4) Informants cited a number of leadership behaviors not yet accounted for in the leadership behavior literature (e.g., 'hands on', 'professional', 'knows organization'). (5) Ineffective leadership behavior is not simply the opposite of effective leadership. Findings support the following ideas: (1) there may be a relationship between the type of job held by employees in health care organizations and their perceptions of leader behavior, and (2) leadership behavior theories are not yet comprehensive enough to account for the varieties of leadership behavior in a health care organization. This study is limited by the fact that it focused on only those leadership theories that considered leader behavior. There are two practical implications for health care organizations. (1) leaders should recognize that the type of behavior an employee prefers from a leader may vary by follower job group (e.g., nurses may prefer relational behavior more than managerial staff do), and (2) organizations could improve leader development programs and evaluation

  16. EQUINE THERMOREGULATORY RESPONSES DURING SUMMERTIME ROAD TRANSPORT AND STALL CONFINEMENT

    Directory of Open Access Journals (Sweden)

    ANGELA R. GREEN

    2007-04-01

    Full Text Available Thermoregulatory responses of horses subjected to summer-time road transport and stall confinement were investigated in this study. Six mature geldings were transported 168 km in a 4-horse trailer and were monitored while tethered in their stalls, on alternate days. Core body temperature (GT demonstrated negligible response during transport, but GT following transport was higher than GT for non-transport. GT tended to increase with increased temperature humidity index (THI. THI within the trailer was greatest for positions near the front, and was influenced by daily weather which varied over experiment days from heat stress conditions to moderate discomfort.

  17. A dynamic stall model for airfoils with deformable trailing edges

    DEFF Research Database (Denmark)

    Andersen, Peter Bjørn; Gaunaa, Mac; Bak, Christian

    2009-01-01

    The present work contains an extension of the Beddoes-Leishman-type dynamic stall model. In this work, a deformable trailing-edge flap has been added to the dynamic stall model. The model predicts the unsteady aerodynamic forces and moments on an airfoil section undergoing arbitrary motion in hea...... for the attached flow region and Hansen et al. The model is compared qualitatively to wind tunnel measurements of a Riso/ B1-18 blade section equipped with deformable trailing-edge flap devices in the form of piezoelectric devices. Copyright © 2009 John Wiley & Sons, Ltd....

  18. Regulation of bacterial gene expression by ribosome stalling and rescuing.

    Science.gov (United States)

    Jin, Yongxin; Jin, Shouguang; Wu, Weihui

    2016-05-01

    Ribosome is responsible for protein synthesis and is able to monitor the sequence and structure of the nascent peptide. Such ability plays an important role in determining overall gene expression profile of the bacteria through ribosome stalling and rescuing. In this review, we briefly summarize our current understanding of the regulation of gene expression through ribosome stalling and rescuing in bacteria, as well as mechanisms that modulate ribosome activity. Understanding the mechanisms of how bacteria modulate ribosome activity will provide not only fundamental insights into bacterial gene regulation, but also new candidate targets for the development of novel antimicrobial agents.

  19. A dynamic stall model for airfoils with deformable trailing edges

    DEFF Research Database (Denmark)

    Andersen, Peter Bjørn; Gaunaa, Mac; Bak, Dan Christian

    2007-01-01

    on an airfoil section undergoing arbitrary motion in heave, lead-lag, pitch, Trailing Edge (TE) flapping. In the linear region, the model reduces to the inviscid model of Gaunaa [4], which includes the aerodynamic effect of a thin airfoil with a deformable camberline in inviscid flow. Therefore, the proposed......The present work contains an extension of the Beddoes-Leishman (B-L) type dynamic stall model, as described by Hansen et al. [7]. In this work a Deformable Trailing Edge Geometry (DTEG) has been added to the dynamic stall model. The model predicts the unsteady aerodynamic forces and moments...

  20. Dynamic Stall Flow Control Through the Use of a Novel Plasma Based Actuator Technology, Phase I

    Data.gov (United States)

    National Aeronautics and Space Administration — Lynntech proposes a novel flow control methodology for airfoils undergoing dynamic stall. Dynamic stall refers to an aerodynamic phenomenon that is experienced by...

  1. Unsteady Double Wake Model for the Simulation of Stalled Airfoils

    DEFF Research Database (Denmark)

    Ramos García, Néstor; Cayron, Antoine; Sørensen, Jens Nørkær

    2015-01-01

    separation and its dynamics. In this paper, the calculated integral forces have been successfully validated against wind tunnel measurements for the FFA-W3-211 airfoil. Furthermore, the computed highly unsteady flow field is analyzed in detail for a set of angles of attack ranging from light to deep stall...

  2. Dynamic Characteristics of Rotating Stall in Mixed Flow Pump

    Directory of Open Access Journals (Sweden)

    Xiaojun Li

    2013-01-01

    Full Text Available Rotating stall, a phenomenon that causes flow instabilities and pressure hysteresis by propagating at some fraction of the impeller rotational speed, can occur in centrifugal impellers, mixed impellers, radial diffusers, or axial diffusers. Despite considerable efforts devoted to the study of rotating stall in pumps, the mechanics of this phenomenon are not sufficiently understood. The propagation mechanism and onset of rotating stall are not only affected by inlet flow but also by outlet flow as well as the pressure gradient in the flow passage. As such, the complexity of these concepts is not covered by the classical explanation. To bridge this research gap, the current study investigated prerotation generated at the upstream of the impeller, leakage flow at the tip clearance between the casing and the impeller, and strong reserve flow at the inlet of the diffuser. Understanding these areas will clarify the origin of the positive slope of the head-flow performance curve for a mixed flow pump. Nonuniform pressure distribution and adverse pressure gradient were also introduced to evaluate the onset and development of rotating stall within the diffuser.

  3. The Mechanical Impact of Aerodynamic Stall on Tunnel Ventilation Fans

    Directory of Open Access Journals (Sweden)

    A. G. Sheard

    2012-01-01

    Full Text Available This paper describes work aimed at establishing the ability of a tunnel ventilation fan to operate without risk of mechanical failure in the event of aerodynamic stall. The research establishes the aerodynamic characteristics of a typical tunnel ventilation fan when operated in both stable and stalled aerodynamic conditions, with and without an anti-stall stabilisation ring, with and without a “nonstalling” blade angle and at full, half, and one quarter design speed. It also measures the fan’s peak stress, thus facilitating an analysis of the implications of the experimental results for mechanical design methodology. The paper concludes by presenting three different strategies for tunnel ventilation fan selection in applications where the selected fan will most likely stall. The first strategy selects a fan with a low-blade angle that is nonstalling. The second strategy selects a fan with a high-pressure developing capability. The third strategy selects a fan with a fitted stabilisation ring. Tunnel ventilation system designers each have their favoured fan selection strategy. However, all three strategies can produce system designs within which a tunnel ventilation fan performs reliably in-service. The paper considers the advantages and disadvantages of each selection strategy and considered the strengths and weaknesses of each.

  4. THE IMPACT OF LOCALIZATION AND BARN TYPE ON INSOLATION OF SIDEWALL STALLS DURING SUMMER

    Directory of Open Access Journals (Sweden)

    Sabina Angrecka

    2017-07-01

    The obtained results allowed us to identify optimal orientation of barns and to suggest the simplest technical measures to protect sidewall stalls from solar heat gain deleterious to cows. The model analysis of stall shading demonstrated that extension of barn eaves to 1 m on the southern side reduced the insolation of stalls over even up to 90% of their area.

  5. Simulation Model of an Active-stall Fixed-speed Wind Turbine Controller

    DEFF Research Database (Denmark)

    Jauch, Clemens; Hansen, Anca D.; Soerensen, Poul

    2004-01-01

    This paper describes an active-stall wind turbine controller. The objective is to develop a general model of an active stall controller in order to simulate the operation of grid connected active stall wind turbines. The active stall turbine concept and its control strategies are presented...... and evaluated by simulations. The presented controller is described for continuous operation under all wind speeds from start-up wind speed to shut down wind speed. Due to its parametric implementation it is general i.e. it can represent different active stall wind turbine controllers and can be implemented...

  6. Simulation model of an active-stall fixed-speed wind turbine controller

    Energy Technology Data Exchange (ETDEWEB)

    Jauch, C.; Hansen, A.D.; Sorensen, P.; Blaabjerg, F.

    2004-07-01

    This paper describes an active-stall wind turbine controller. The objective is to develop a general model of an active stall controller in order to simulate the operation of grid connected active stall wind turbines. The active stall turbine concept and its control strategies are presented and evaluated by simulations. The presented controller is described for continuous operation under all wind speeds from start-up wind speed to shut down wind speed. Due to its parametric implementation it is general i. e. it can represent different active stall wind turbine controllers and can be implemented in different simulation tools. (author)

  7. Flexible and fixed partitions in freestalls--effects on lying behavior and cow preference.

    Science.gov (United States)

    Ruud, L E; Bøe, K E

    2011-10-01

    The objective was to investigate the effect of stall partition design on total lying time, lying position, and stall cleanliness, and to evaluate the preferences of cows regarding stalls with traditional fixed stall dividers or flexible stall dividers. Using a crossover design, 16 nonlactating dairy cows were housed singly for 9 d in pens with 2 freestalls, 1 with fixed cantilever dividers and 1 with flexible dividers. The cows were first given access to one stall type, and then to the other type of stall, and finally to both in a preference test. Type of stall divider did not influence lying behavior (13.5h for fixed versus 14.0 h for flexible, ± 0.4h), lying positions, or stall cleanliness; however, the cows showed a preference for lying in the flexible stalls (65.2 for flexible vs. 34.8 for fixed ± 8.2%). This indicated that cows are able to distinguish between type of stall divider and that it is important to them; however, it is not clear if the reason for this is the shape or the properties of the dividers. We concluded that cattle chose a flexible stall divider over a fixed one, but the long-term consequences of this preference are not clear, because no obvious changes in stall usage were observed when cows were only given access to one type of divider. Copyright © 2011 American Dairy Science Association. Published by Elsevier Inc. All rights reserved.

  8. Flow and Noise Characteristics of Centrifugal Fan under Different Stall Conditions

    Directory of Open Access Journals (Sweden)

    Lei Zhang

    2014-01-01

    Full Text Available An implicit, time-accurate 3D Reynolds-averaged Navier-Stokes (RANS solver is used to simulate the rotating stall phenomenon in a centrifugal fan. The goal of the present work is to shed light on the flow field and particularly the aerodynamic noise at different stall conditions. Aerodynamic characteristics, frequency domain characteristics, and the contours of sound power level under two different stall conditions are discussed in this paper. The results show that, with the decrease of valve opening, the amplitude of full pressure and flow fluctuations tends to be larger and the stall frequency remains the same. The flow field analysis indicates that the area occupied by stall cells expands with the decrease of flow rate. The noise calculation based on the simulation underlines the role of vortex noise after the occurrence of rotating stall, showing that the high noise area rotates along with the stall cell in the circumferential direction.

  9. Numerical study on a single bladed vertical axis wind turbine under dynamic stall

    Energy Technology Data Exchange (ETDEWEB)

    Bangga, Galih [Institute of Aerodynamics and Gas Dynamics, University of Stuttgart, Stuttgart (Germany); Hutomo, Go; Sasongko, Herman [Dept. of Mechanical Engineering, Institut Teknologi Sepuluh Nopember, Surabaya (Indonesia); Wiranegara, Raditya [School of Mechanical Aerospace and Civil Engineering, University of Manchester, Manchester (United Kingdom)

    2017-01-15

    The aim of this study is to investigate the flow development of a single bladed vertical axis wind turbine using Computational fluid dynamics (CFD) methods. The blade is constructed using the NACA 0012 profile and is operating under stalled conditions at tip speed ratio of 2. Two dimensional simulations are performed using a commercial CFD package, ANSYS Fluent 15.0, employing the Menter-SST turbulence model. For the preliminary study, simulations of the NACA 0012 airfoil under static conditions are carried out and compared with available measurement data and calculations using the boundary layer code XFOIL. The CFD results under the dynamic case are presented and the resulting aerodynamic forces are evaluated. The turbine is observed to generate negative power at certain azimuth angles which can be divided into three main zones. The blade vortex interaction is observed to strongly influence the flow behavior near the blade and contributes to the power production loss. However, the impact is considered small since it covers only 6.4 % of the azimuth angle range where the power is negative compared to the dynamic stall impact which covers almost 22 % of the azimuth angle range.

  10. Compliance with NAGCAT work practices recommendations for youth cleaning service alleys in stall barns.

    Science.gov (United States)

    Canan, B D; Asti, L; Heaney, C; Ashida, S; Renick, K; Xiang, H; Stallones, L; Jepsen, S D; Crawford, J M; Wilkins, J R

    2011-04-01

    Unintentional injury is the leading cause of death in the U.S. among persons 1 to 44 years of age. Over one million children and adolescents in the U.S. live, work, and/or play on farms, where injury risk is relatively high compared to other settings. In an attempt to reduce the number of childhood agricultural injuries occurring on farms, the North American Guidelines for Children's Agricultural Tasks (NAGCAT) was developed to assist parents or other caregivers in assigning developmentally appropriate chores to youth exposed to agricultural hazards. The results presented here are from a longitudinal study in which we obtained (self-reported) daily chore, injury, and safety behavior data from children and adolescents. We focused on one NAGCAT chore, cleaning a service alley in a stall barn, in order to estimate the extent of compliance with specific work practice recommendations contained in the NAGCAT. Our results indicated that among the four NAGCAT-recommended safety practices for cleaning service alleys in stall barns (wearing nonskid shoes, leather gloves, a respirator, and eye protection), wearing non-skid shoes was the only safety practice reported with any degree of regularity. Overall, boys were more likely to wear non-skid shoes compared to girls. In addition, older youth were generally more likely to report higher work practice compliance compared to younger youth.

  11. DYNSTALL: Subroutine package with a dynamic stall model

    Energy Technology Data Exchange (ETDEWEB)

    Bjoerck, Anders [Aeronautical Research Inst. of Sweden, Bromma (Sweden)

    2001-03-01

    A subroutine package, called DYNSTALL, for the calculation of 2D unsteady airfoil aerodynamics is described. The subroutines are written in FORTRAN. DYNSTALL is basically an implementation of the Beddoes-Leishman dynamic stall model. This model is a semi-empirical model for dynamic stall. It includes, however, also models for attached flow unsteady aerodynamics. It is complete in the sense that it treats attached flow as well as separated flow. Semi-empirical means that the model relies on empirically determined constants. Semi because the constants are constants in equations with some physical interpretation. It requires the input of 2D airfoil aerodynamic data via tables as function of angle of attack. The method is intended for use in an aeroelastic code with the aerodynamics solved by blade/element method. DYNSTALL was written to work for any 2D angles of attack relative to the airfoil, e.g. flow from the rear of an airfoil.

  12. Study and Control of a Radial Vaned Diffuser Stall

    Directory of Open Access Journals (Sweden)

    Aurélien Marsan

    2012-01-01

    Full Text Available The aim of the present study is to evaluate the efficiency of a boundary layer suction technique in case of a centrifugal compressor stage in order to extend its stable operating range. First, an analysis of the flow pattern within the radial vaned diffuser is presented. It highlights the stall of the diffuser vanes when reaching a low massflow. A boundary layer separation in the hub-suction side corner grows when decreasing the massflow from the nominal operating point to the surge and finally leads to a massive stall. An aspiration strategy is investigated in order to control the stall. The suction slot is put in the vicinity of the saddle that originates the main separating skin-friction line, identified thanks to the analysis of the skin-friction pattern. Several aspiration massflow rates are tested, and two different modelings of the aspiration are evaluated. Finally, an efficient control is reached with a removal of only 0,1% of the global massflow and leads—from a steady-state calculations point of view—to an increase by 40% of the compressor operating range extent.

  13. Vorticity Transport on a Flexible Wing in Stall Flutter

    Science.gov (United States)

    Akkala, James; Buchholz, James; Farnsworth, John; McLaughlin, Thomas

    2014-11-01

    The circulation budget within dynamic stall vortices was investigated on a flexible NACA 0018 wing model of aspect ratio 6 undergoing stall flutter. The wing had an initial angle of attack of 6 degrees, Reynolds number of 1 . 5 ×105 and large-amplitude, primarily torsional, limit cycle oscillations were observed at a reduced frequency of k = πfc / U = 0 . 1 . Phase-locked stereo PIV measurements were obtained at multiple chordwise planes around the 62.5% and 75% spanwise locations to characterize the flow field within thin volumetric regions over the suction surface. Transient surface pressure measurements were used to estimate boundary vorticity flux. Recent analyses on plunging and rotating wings indicates that the magnitude of the pressure-gradient-driven boundary flux of secondary vorticity is a significant fraction of the magnitude of the convective flux from the separated leading-edge shear layer, suggesting that the secondary vorticity plays a significant role in regulating the strength of the primary vortex. This phenomenon is examined in the present case, and the physical mechanisms governing the growth and evolution of the dynamic stall vortices are explored. This work was supported by the Air Force Office of Scientific Research through the Flow Interactions and Control Program monitored by Dr. Douglas Smith, and through the 2014 AFOSR/ASEE Summer Faculty Fellowship Program (JA and JB).

  14. Simulasi Numerik Dynamic Stall Pada Airfoil Yang Berosilasi

    Directory of Open Access Journals (Sweden)

    Galih S.T.A. Bangga

    2012-09-01

    Full Text Available Kebutuhan analisa pada sudu helikopter, kompresor, kincir angin dan struktur streamline lainya yang beroperasi pada angle of attack yang tinggi dan melibatkan instationary effects yang disebut dynamic stall menjadi semakin penting. Fenomena ini ditandai dengan naiknya dynamic lift melewati static lift maksimum pada critical static stall angle, vortex yang terbentuk pada leading edge mengakibatkan naiknya suction contribution yang kemudian terkonveksi sepanjang permukaan hingga mencapai trailling edge diikuti terbentuknya trailling edge vortex yang menunjukkan terjadinya lift stall. Fenomena ini sangat berbahaya terhadap struktur airfoil itu sendiri. Secara umum, beban fatique yang ditimbulkan oleh adanya efek histerisis karena fluktuasi gaya lift akibat induksi vibrasi lebih besar dibandingkan kondisi statis. Simulasi numerik dilakukan secara 2D dengan menggunakan profil Boeing-Vertol V23010-1.58 pada α0 = 14.92°. Standard-kω dan SST-kω digunakan sebagai URANS turbulence modelling. Model osilasi dari airfoil disusun dalam suatu user defined function (UDF. Gerakan meshing beserta airfoil diakomodasi dengan menggunakan dynamic mesh approach. Simulasi numerik menunjukkan bahwa, model SST-kω menunjukkan performa yang lebih baik dibandingkan dengan Standard-kω. Fenomena travelling vortex yang terjadi mampu ditangkap dengan baik, meski pada angle of attack yang tinggi URANS turbulence model gagal memprediksikan fenomena yang terjadi karena dominasi efek 3D.

  15. Prediction of dynamic loads and induced vibrations in stall

    Energy Technology Data Exchange (ETDEWEB)

    Thirstrup Petersen, J.; Aagaard Madsen, H. [Risoe National Lab. (Denmark); Bjoerck, A. [Aeronautical Research Inst. of Sweden (Sweden); Enevoldsen, P. [Bonus Energy A/S (Denmark); Oeye, S. [The Technical Univ. of Denmark (Denmark); Ganander, H. [Teknikgruppen AB (Sweden); Winkelaar, D. [Netherlands Energy Research Foundation (Netherlands)

    1998-05-01

    Results from research in an EC Joule-III project and from national projects are presented. The objectives are improvement of design methods for stall regulated wind turbines with emphasis on stall induced vibrations and dynamic stall. The primary concern is limitation of the edgewise vibrations in the fundamental blade natural mode shape, which have caused trouble on modern wind turbines of approximate size 500 kW nominal power and 40 m rotor diameter. A theoretical study of quasi-steady aerodynamics confirms that the vibrations are driven basically by energy supplied from the aerodynamic forces during stalled operation. This energy exchange is equivalent to negative aerodynamic damping. The theoretical approach identifies the main parameters controlling the phenomenon. These parameters describe the steady and the dynamic airfoil characteristics, the overall aerodynamic layout of the blade, e.g. chord length and twist, the structural properties of the blade, e.g. structural damping and properties controlling the resulting vibration direction. Furthermore, full aeroelastic calculations and comparison with measurements show that the properties of the supporting structure, i.e. the main shaft, the nacelle and the tower, are important, as the global vibration of the rotor on its support may exchange energy with the blade vibration, when the blade natural frequency is close to one of the frequencies of the coupled rotor tilt-yaw mode shapes, usually denoted the global rotor whirl frequencies. It is confirmed that the influence of changing the primary design parameters can be determined by use of qualified aeroelastic calculations. Presented design guidelines therefore build on both the simple quasi-steady models, which can be used for the preliminary choice of the design variables mentioned above, and on full aeroelastic calculations. The aeroelastic calculations refine the design basis and should be used for choosing the final design variables and for final

  16. Precautions against axial fan stall in reactor building to Tianwan NPP

    International Nuclear Information System (INIS)

    Liu Chunlong; Pei Junmin

    2011-01-01

    The paper introduces the mechanism and harm of rotating stall of axial fans, analyzes the necessity for prevention against axial fan stall in reactor building of Tianwan NPP, introduces the precautions, and then makes an assessment on anti-stall effect of flow separators. It can provide reference for model-selection or reconstruction of similar fans in power stations, and for operation and maintenance of axial fans. (authors)

  17. Comparison of Different Stall Conditions in Axial Flow Compressor Using Analytic Wavelet Transform

    Directory of Open Access Journals (Sweden)

    Arshad Ali

    2017-12-01

    Full Text Available The rotating stall inception data analysis using Analytic Wavelet Transform (AWT in a low-speed axial compressor was presented in the authors’ previous studies [1], [2]. These studies focused on the detection of instability inception in an axial flow compressor when it enters into the instability regime due to the modal type of stall perturbation. In this paper, the effectiveness of AWT is further studied by applying it under different testing conditions. In order to examine the results of AWT on highly sampled data, at first, the stall data were acquired at a high sampling frequency and the results were compared with the conventional filtered signals. Secondly, the AWT analysis of stall data was carried out for the condition when compressor experienced a spike type rotating stall disturbance. The stall inception information obtained from the AWT analysis was then compared with the commonly used stall detection techniques. The results show that AWT is equally beneficial for the diagnostic of compressor instability regardless of the data sampling rate and represents an outstanding ability to detect stall disturbance irrespective of the type of stall precursor, i.e. the modal wave or spike.

  18. Enhancing BEM simulations of a stalled wind turbine using a 3D correction model

    Science.gov (United States)

    Bangga, Galih; Hutomo, Go; Syawitri, Taurista; Kusumadewi, Tri; Oktavia, Winda; Sabila, Ahmad; Setiadi, Herlambang; Faisal, Muhamad; Hendranata, Yongki; Lastomo, Dwi; Putra, Louis; Kristiadi, Stefanus; Bumi, Ilmi

    2018-03-01

    Nowadays wind turbine rotors are usually employed with pitch control mechanisms to avoid deep stall conditions. Despite that, wind turbines often operate under pitch fault situation causing massive flow separation to occur. Pure Blade Element Momentum (BEM) approaches are not designed for this situation and inaccurate load predictions are already expected. In the present studies, BEM predictions are improved through the inclusion of a stall delay model for a wind turbine rotor operating under pitch fault situation of -2.3° towards stall. The accuracy of the stall delay model is assessed by comparing the results with available Computational Fluid Dynamics (CFD) simulations data.

  19. Numerical simulation of the RISOe1-airfoil dynamic stall

    Energy Technology Data Exchange (ETDEWEB)

    Bertagnolio, F.; Soerensen, N. [Risoe National Lab., Wind Energy and Atmospheric Physics Dept., Roskilde (Denmark)

    1997-12-31

    In this paper we are concerned with the numerical computation of the dynamic stall that occur in the viscous flowfield over an airfoil. These results are compared to experimental data that were obtained with the new designed RISOe1-airfoil, both for a motionless airfoil and for a pitching motion. Moreover, we present some numerical computations of the plunging and lead-lag motions. We also investigate the possibility of using the pitching motion to simulate the plunging and lead-lag situations. (au)

  20. El departamento musical Disney : las Silly Symphonies y Carl Stalling

    OpenAIRE

    Duarte del Moral, Marina

    2014-01-01

    La historia de la animación tiene un nombre propio: Walt Disney. Gracias a su experimentación en diversos campos de esta materia, Disney consigue desarrollar la animación y su universo de una forma perseverante y continua, adaptándose a los diversos cambios producidos desde el nacimiento de ésta, reinventando una y otra vez el sector y añadiendo su toque mágico a la personalidad de cada personaje y cada obra. En este camino no está solo gracias al trabajo de genios como Carl Stalling, que apo...

  1. FBH1 Catalyzes Regression of Stalled Replication Forks

    DEFF Research Database (Denmark)

    Fugger, Kasper; Mistrik, Martin; Neelsen, Kai J

    2015-01-01

    DNA replication fork perturbation is a major challenge to the maintenance of genome integrity. It has been suggested that processing of stalled forks might involve fork regression, in which the fork reverses and the two nascent DNA strands anneal. Here, we show that FBH1 catalyzes regression......, is required for early phosphorylation of ATM substrates such as CHK2 and CtIP as well as hyperphosphorylation of RPA. These phosphorylations occur prior to apparent DNA double-strand break formation. Furthermore, FBH1-dependent signaling promotes checkpoint control and preserves genome integrity. We propose...

  2. The FFA dynamic stall model. The Beddoes-Leishman dynamic stall model modified for lead-lag oscillations

    Energy Technology Data Exchange (ETDEWEB)

    Bjoerck, A. [FFA, The Aeronautical Research Institute of Sweden, Bromma (Sweden)

    1997-08-01

    For calculations of the dynamics of wind turbines the inclusion of a dynamic stall model is necessary in order to obtain reliable results at high winds. For blade vibrations in the lead-lag motion the velocity relative to the blade will vary in time. In the present paper modifications to the Beddoes-Leishman model is presented in order to improve the model for calculations of cases with a varying relative velocity. Comparisons with measurement are also shown and the influence on the calculated aerodynamic damping by the modifications are investigated. (au)

  3. A.C. Plasma Anemometer for Axial Compressor Stall Warning

    Science.gov (United States)

    Matlis, Eric; Cameron, Joshua; Morris, Scott; Corke, Thomas

    2007-11-01

    Compressor sections of turbo jet engines are subject to stall and surge as a result of flow instabilities that occur upstream of the compressor rotor. One of the instability modes that contributes to compressor surge is the so-called `spike' mode of stall inception. It has been shown that this mode of instability can be predicted before onset by performing real-time statistical auto-correlation measurements of the blade-passing pressure characteristic at the mid-chord location of the rotor. These measurements are performed with pressure sensors or hot-wires that are too fragile for a full-scale compressor. We have developed a sensor that can survive the vibration and temperatures of a full-scale rig while providing the bandwidth necessary to resolve the blade passage signature required by this coherence technique. This sensor, called the Plasma Anemometer, provides high-bandwith point measurements of velocity or pressure fluctuations with unparalleled mechanical robustness and resistance to vibration and thermal effects.

  4. Evaluating Classroom Interaction with the iPad®: An Updated Stalling's Tool

    Science.gov (United States)

    MacKinnon, Gregory; Schep, Lourens; Borden, Lisa Lunney; Murray-Orr, Anne; Orr, Jeff; MacKinnon, Paula

    2016-01-01

    A large study of classrooms in the Caribbean context necessitated the use of a validated classroom observation tool. In practice, the paper-version Stalling's instrument (Stallings & Kaskowitz 1974) presented specific challenges with respect to (a) facile data collection and (b) qualitative observations of classrooms. In response to these…

  5. Simulation of Entropy Generation under Stall Conditions in a Centrifugal Fan

    Directory of Open Access Journals (Sweden)

    Lei Zhang

    2014-06-01

    Full Text Available Rotating stalls are generally the first instability met in turbomachinery, before surges. This 3D phenomenon is characterized by one or more stalled flow cells which rotate at a fraction of the impeller speed. The goal of the present work is to shed some light on the entropy generation in a centrifugal fan under rotating stall conditions. A numerical simulation of entropy generation is carried out with the ANSYS Fluent software which solves the Navier-Stokes equations and user defined function (UDF. The entropy generation characteristics in the centrifugal fan for five typical conditions are presented and discussed, involving the design condition, conditions on occurrence and development of stall inception, the rotating stall conditions with two throttle coefficients. The results show that the entropy generation increases after the occurrence of stall inception. The high entropy generation areas move along the circumferential and axial directions, and finally merge into one stall cell. The entropy generation rate during circumferential propagation of the stall cell is also discussed, showing that the entropy generation history is similar to sine curves in impeller and volute, and the volute tongue has a great influence on entropy generation in the centrifugal fan.

  6. Has Uganda experienced any stalled fertility transitions? Reflecting on the last four decades (1973-2011).

    Science.gov (United States)

    Kabagenyi, Allen; Reid, Alice; Rutaremwa, Gideon; Atuyambe, Lynn M; Ntozi, James P M

    2015-09-23

    Persistent high fertility is associated with mother and child mortality. While most regions in the world have experienced declines in fertility rates, there are conflicting views as to whether Uganda has entered a period of fertility transition. There are limited data available that explicitly detail the fertility trends and patterns in Uganda over the last four decades, from 1973 to 2011. Total fertility rate (TFR) is number of live births that a woman would have throughout her reproductive years if she were subject to the prevailing age specific fertility patterns. The current TFR for Uganda stands at 6.2 children born per woman, which is one of the highest in the region. This study therefore sought to examine whether there has been a fertility stall in Uganda using all existing Demographic Health Survey data, to provide estimates for the current fertility levels and trends in Uganda, and finally to examine the demographic and socioeconomic factors responsible for fertility levels in Uganda. This is a secondary analysis of data from five consecutive Ugandan Demographic Health Surveys (UDHS); 1988/1989, 1995, 2000/2001, 2006 and 2011. Using pooled data to estimate for fertility levels, patterns and trends, we applied a recently developed fertility estimation approach. A Poisson regression model was also used to analyze fertility differentials over the study period. Over the studied period, fertility trends and levels fluctuated from highs of 8.8 to lows of 5.7, with no specific lag over the study period. These findings suggest Uganda is at the pre-transitional stage, with indications of imminent fertility rate reductions in forthcoming years. Marital status remained a strong predictor for number of children born, even after controlling for other variables. This study suggests there is no evidence of a fertility stall in Uganda, but demonstrates an onset of fertility transition in the country. If this trend continues, Uganda will experience a low fertility rate in

  7. Optimal parameters for the FFA-Beddoes dynamic stall model

    Energy Technology Data Exchange (ETDEWEB)

    Bjoerck, A.; Mert, M. [FFA, The Aeronautical Research Institute of Sweden, Bromma (Sweden); Madsen, H.A. [Risoe National Lab., Roskilde (Denmark)

    1999-03-01

    Unsteady aerodynamic effects, like dynamic stall, must be considered in calculation of dynamic forces for wind turbines. Models incorporated in aero-elastic programs are of semi-empirical nature. Resulting aerodynamic forces therefore depend on values used for the semi-empiricial parameters. In this paper a study of finding appropriate parameters to use with the Beddoes-Leishman model is discussed. Minimisation of the `tracking error` between results from 2D wind tunnel tests and simulation with the model is used to find optimum values for the parameters. The resulting optimum parameters show a large variation from case to case. Using these different sets of optimum parameters in the calculation of blade vibrations, give rise to quite different predictions of aerodynamic damping which is discussed. (au)

  8. Proposed Chevron Tengiz venture stalls amid Soviet political squabble

    International Nuclear Information System (INIS)

    Anon.

    1991-01-01

    This paper reports on the status of foreign investment in Soviet oil and gas joint ventures which has reached a critical juncture. Just as the U.S. is considering granting most favored nation trade status to the U.S.S.R., the joint venture petroleum deal seen as the litmus test for such deals-Chevron Corp.'s proposed addition of supergiant Tengiz oil field to its Caspian Sea joint venture-has stalled amid controversy. Unconfirmed reports from Soviet officials and other foreign joint venture participants in the U.S.S.R. have Chevron pulling out of the long negotiated, multibillion dollar project after the Soviets rejected the company's terms. Chevron, however, insists the project is still alive

  9. Introducing sit-stand desks increases classroom standing time among university students

    Directory of Open Access Journals (Sweden)

    Matthew Jerome

    2017-12-01

    Full Text Available Excessive sedentary behavior has been associated with many negative health outcomes. While an understudied health topic, there is evidence that university students are excessively sedentary. Sit-stand desks have been shown to reduce sedentary time among pre-university students (ages 5–18years and sedentary workers but have not been tested in university classrooms. This study tested the effects of introducing sit-stand desks into a university classroom on student's classroom sitting and standing behaviors. Using a cross-over design, students received access to both traditional seated desks and sit-stand desks for six weeks. Data were collected between September and December, 2016. We recruited 304 healthy undergraduate university students enrolled in one of two small (25 seats classrooms at a large Midwestern university during the fall of 2016. Average minutes of standing/hour/student, average percent class time spent standing, and the number of sit-stand transitions/student/hour were directly observed with video camera surveillance. Participants stood significantly more (p<0.001 when provided access to sit-stand desks (7.2min/h/student; 9.3% of class time spent standing compared to when they had access to seated desks (0.7min/h/student; 1.6% of class time spent standing but no differences were observed for the number of sit-stand transitions (p=0.47. Students reported high favorability for the sit-stand desks and improvements in several student engagement and affective outcomes while using the sit-stand desks. These findings support introducing sit-stand desks in university classrooms as an approach to reduce sedentary behaviors of university students. Keywords: Sedentary, University students, Sit-stand desk

  10. Analysis of Low Speed Stall Aerodynamics of a Swept Wing with Laminar Flow Glove

    Science.gov (United States)

    Bui, Trong T.

    2014-01-01

    Reynolds-Averaged Navier-Stokes (RANS) computational fluid dynamics (CFD) analysis was conducted to study the low-speed stall aerodynamics of a GIII aircraft's swept wing modified with a laminar-flow wing glove. The stall aerodynamics of the gloved wing were analyzed and compared with the unmodified wing for the flight speed of 120 knots and altitude of 2300 ft above mean sea level (MSL). The Star-CCM+ polyhedral unstructured CFD code was first validated for wing stall predictions using the wing-body geometry from the First American Institute of Aeronautics and Astronautics (AIAA) CFD High-Lift Prediction Workshop. It was found that the Star-CCM+ CFD code can produce results that are within the scattering of other CFD codes considered at the workshop. In particular, the Star-CCM+ CFD code was able to predict wing stall for the AIAA wing-body geometry to within 1 degree of angle of attack as compared to benchmark wind-tunnel test data. Current results show that the addition of the laminar-flow wing glove causes the gloved wing to stall much earlier than the unmodified wing. Furthermore, the gloved wing has a different stall characteristic than the clean wing, with no sharp lift drop-off at stall for the gloved wing.

  11. Analysis of Low-Speed Stall Aerodynamics of a Swept Wing with Laminar-Flow Glove

    Science.gov (United States)

    Bui, Trong T.

    2014-01-01

    Reynolds-Averaged Navier-Stokes (RANS) computational fluid dynamics (CFD) analysis was conducted to study the low-speed stall aerodynamics of a GIII aircraft's swept wing modified with a laminar-flow wing glove. The stall aerodynamics of the gloved wing were analyzed and compared with the unmodified wing for the flight speed of 120 knots and altitude of 2300 ft above mean sea level (MSL). The Star-CCM+ polyhedral unstructured CFD code was first validated for wing stall predictions using the wing-body geometry from the First American Institute of Aeronautics and Astronautics (AIAA) CFD High-Lift Prediction Workshop. It was found that the Star-CCM+ CFD code can produce results that are within the scattering of other CFD codes considered at the workshop. In particular, the Star-CCM+ CFD code was able to predict wing stall for the AIAA wing-body geometry to within 1 degree of angle of attack as compared to benchmark wind-tunnel test data. Current results show that the addition of the laminar-flow wing glove causes the gloved wing to stall much earlier than the unmodified wing. Furthermore, the gloved wing has a different stall characteristic than the clean wing, with no sharp lift drop-off at stall for the gloved wing.

  12. Investigating Stall Flutter using a DS model-An application for HAWTs

    International Nuclear Information System (INIS)

    Nichols, James; Haans, Wouter; Witcher, David; Attorni, Andrea

    2014-01-01

    As wind turbine blades become larger there is a tendency for the blade torsional stiffness to reduce, producing the possibility of dynamic instability at moderate windspeeds. While linearised methods can assess the envelope of allowable blade properties for avoiding classical flutter with attached flow aerodynamics, wind turbine aerofoils can experience stalled flow. Therefore, it is necessary to explore the possible effects of stall-flutter on blade stability. This paper aims to address methods for judging the stability of blade designs during both attached flow and stalled flow behaviour. This paper covers the following areas: i) Attached flow model A Beddoes-Leishman indicial model is presented and the choice of coefficients is explained in the context of Theodorsen's theory for flat-plate aerofoils and experimental results by Beddoes and Leishman. Special attention is given to the differing dynamic behaviour of the pitching moment due to flapping motion, pitching motion and dynamically varying inflow. (ii) Classical flutter analysis The time domain attached flow model is verified against a linear flutter analysis by comparing time domain results for a 3D model of a representative multi-megawatt turbine blade, varying the position of the centre of mass along the chord. The results show agreement to within 6% for a range of flutter onset speeds. (iii) Dynamic stall model On entering the stalled region, damping of torsional motion of an aerofoil section can become negative. A dynamic stall model which encompasses the effects of trailing edge separation and leading edge vortex detachment is presented and validated against published experimental data. (iv) Stall flutter The resulting time domain model is used in simulations validating the prediction of reduced flutter onset for stalled aerofoils. Representative stalled conditions for a multi-megawatt wind turbine blade are investigated to assess the possible reduction in flutter speed. A maximum reduction of 17

  13. Analysis of Low-Speed Stall Aerodynamics of a Business Jets Wing Using STAR-CCM+

    Science.gov (United States)

    Bui, Trong

    2016-01-01

    Reynolds-Averaged Navier-Stokes (RANS) computational fluid dynamics (CFD) analysis was conducted: to study the low-speed stall aerodynamics of a GIII aircrafts swept wing modified with (1) a laminar-flow wing glove, or (2) a seamless flap. The stall aerodynamics of these two different wing configurations were analyzed and compared with the unmodified baseline wing for low-speed flight. The Star-CCM+ polyhedral unstructured CFD code was first validated for wing stall predictions using the wing-body geometry from the First AIAA CFD High-Lift Prediction Workshop.

  14. Assisting children with attention deficit hyperactivity disorder to reduce the hyperactive behavior of arbitrary standing in class with a Nintendo Wii remote controller through an active reminder and preferred reward stimulation.

    Science.gov (United States)

    Shih, Ching-Hsiang; Wang, Shu-Hui; Wang, Yun-Ting

    2014-09-01

    Recent studies in the field of special education have shown that in combination with software technology, high-tech commercial products can be applied as useful assistive technology devices to help people with disabilities. This study extended this concept to turn a Nintendo Wii Remote Controller into a high-performance limb action detector, in order to evaluate whether two students with Attention Deficit Hyperactivity Disorder (ADHD) could reduce their hyperactive behavior through an active reminder and stimulation in the form of the participants' preferred rewards. This study focused on one particular hyperactive behavior common to both students: standing up arbitrarily during class. The active reminder was in the form of vibration feedback provided via the built-in function of the Wii Remote Controller, which was controlled and triggered by a control system to remind participants when they were engaging in standing behavior. This study was performed according to a multiple baseline design across participants. The results showed that both participants significantly improved their control over their hyperactive behavior during the intervention phase, and retained this effective performance in the maintenance phase. The practical and developmental implications of the findings are discussed. Copyright © 2014 Elsevier Ltd. All rights reserved.

  15. The Effects of Gilts Housed Either in Group with the Electronic Sow Feeding System or Conventional Stall.

    Science.gov (United States)

    Jang, J C; Jung, S W; Jin, S S; Ohh, S J; Kim, J E; Kim, Y Y

    2015-10-01

    This experiment was conducted to assess the welfare and productivity of gestating gilts in groups with the electronic sow feeding (ESF) system compared to conventional stalls. A total of 83 gilts (Yorkshire×Landrace) were housed into individual stalls to be artificially inseminated. Gilts confirmed pregnant were introduced to their treatment, conventional stalls (ST) or groups with the ESF system. All gilts were taken to the farrowing crates one week prior to their expected farrowing date. In the gestation period, there were no significant differences between gilts allocated to ST and ESF on growth performance. However, backfat thickness gain (p = 0.08) and body condition score (BCS) at 110 days of gestation (p = 0.10) tended to be higher in ESF gilts than ST. Likewise, gilts housed in group showed significantly higher estimated body muscle contents at 110 days of gestation (p = 0.02) and body muscle change during gestation (p = 0.01). There was a trend for a shorter parturition time in ESF gilts (p = 0.07). In the lactation period, group housed gilts showed a tendency to increased BCS changes (p = 0.06). Reproductive performance did not differ with the exception of piglet mortality (ST = 0.2 no. of piglets vs ESF = 0.4 no. of piglets; p = 0.01). In blood profiles, ST gilts showed a higher cortisol level at 110 days of gestation (p = 0.01). Weaning to estrus interval was shorter in gilts housed in ESF than ST (p = 0.01). In locomotory behaviors, ESF gilts recorded a tendency to elevate locomotion score at 36, 70, and 110 days of gestation (p = 0.07, p = 0.06, and p = 0.06, respectively). Similarly, ESF gilts showed significantly higher incidence of scratches at 36, 70, and 110 days of gestation (p = 0.01). Moreover, farrowing rates were higher in stall treatment (97.6%) compare to group housing treatment (95.2%). In conclusion, while group housed gilts with ESF system positively affected welfare status in combination with less physiologically stressful

  16. A model for roll stall and the inherent stability modes of low aspect ratio wings at low Reynolds numbers

    Science.gov (United States)

    Shields, Matt

    The development of Micro Aerial Vehicles has been hindered by the poor understanding of the aerodynamic loading and stability and control properties of the low Reynolds number regime in which the inherent low aspect ratio (LAR) wings operate. This thesis experimentally evaluates the static and damping aerodynamic stability derivatives to provide a complete aerodynamic model for canonical flat plate wings of aspect ratios near unity at Reynolds numbers under 1 x 105. This permits the complete functionality of the aerodynamic forces and moments to be expressed and the equations of motion to solved, thereby identifying the inherent stability properties of the wing. This provides a basis for characterizing the stability of full vehicles. The influence of the tip vortices during sideslip perturbations is found to induce a loading condition referred to as roll stall, a significant roll moment created by the spanwise induced velocity asymmetry related to the displacement of the vortex cores relative to the wing. Roll stall is manifested by a linearly increasing roll moment with low to moderate angles of attack and a subsequent stall event similar to a lift polar; this behavior is not experienced by conventional (high aspect ratio) wings. The resulting large magnitude of the roll stability derivative, Cl,beta and lack of roll damping, Cl ,rho, create significant modal responses of the lateral state variables; a linear model used to evaluate these modes is shown to accurately reflect the solution obtained by numerically integrating the nonlinear equations. An unstable Dutch roll mode dominates the behavior of the wing for small perturbations from equilibrium, and in the presence of angle of attack oscillations a previously unconsidered coupled mode, referred to as roll resonance, is seen develop and drive the bank angle? away from equilibrium. Roll resonance requires a linear time variant (LTV) model to capture the behavior of the bank angle, which is attributed to the

  17. Initial design of a stall-controlled wind turbine rotor

    Energy Technology Data Exchange (ETDEWEB)

    Nygaard, T.A. [Inst. for Energiteknikk, Kjeller (Norway)

    1997-08-01

    A model intended for initial design of stall-controlled wind turbine rotors is described. The user specifies relative radial position of an arbitrary number of airfoil sections, referring to a data file containing lift-and drag curves. The data file is on the same format as used in the commercial blade-element code BLADES-/2/, where lift- and drag coefficients are interpolated from tables as function of Reynolds number, relative thickness and angle of attack. The user can set constraints on a selection of the following: Maximum power; Maximum thrust in operation; Maximum root bending moment in operation; Extreme root bending moment, parked rotor; Tip speed; Upper and lower bounds on optimisation variables. The optimisation variables can be selected from: Blade radius; Rotational speed; Chord and twist at an arbitrary number of radial positions. The user can chose linear chord distribution and a hyperbola-like twist distribution to ensure smooth planform and twist, or cubic spline interpolation for one or both. The aerodynamic model is based on classical strip theory with Prandtl tip loss correction, supplemented by empirical data for high induction factors. (EG)

  18. Experimental Investigation of Stall Inception Mechanisms of Low Speed Contra Rotating Axial Flow Fan Stage

    Directory of Open Access Journals (Sweden)

    Tegegn Dejene Toge

    2015-01-01

    Full Text Available The present paper is an attempt in understanding the stall inception mechanism in a low speed, contra rotating axial flow fan stage, using wavelet transforms. The rotors used in this study have relatively large tip gap (about 3% of the blade span and aspect ratio of 3. The study was carried out near stall and at stall mass flow conditions for different speed ratios of rotor-2 to rotor-1. Unsteady pressure data from the casing wall mounted sensors are used to understand the stall inception mechanism. The wavelet transform clearly indicates that stall inception occurs mainly through long length scale disturbances for both rotors. It also reveals that short length disturbances occur simultaneously or intermittently in the case of rotor-1. The analysis shows the presence of a strong modal disturbance with 25–80% of the rotor frequency in the case of rotor-1 at the stall mass flow for all the speed combinations studied. The most interesting thing observed in the present study is that the frequency amplitude of the disturbance level is very small for both rotors.

  19. A Method to Predict Compressor Stall in the TF34-100 Turbofan Engine Utilizing Real-Time Performance Data

    Science.gov (United States)

    2015-06-01

    pass turbo –fan engine sensor data to seek its deterioration modelling and prognostics capability. In futurity this will allow for achievement of...preventive maintenance for the TF34-100 jet engine to prevent engine compressor stalls for the A-10 aircraft. Due to their destructive nature, compressor...stalls are a significant concern in axial flow compressor jet engines. A compressor stall is caused by air approaching the compressor blades at an

  20. The Effect of Different Types of Physical Exercise on the Behavioural and Physiological Parameters of Standardbred Horses Housed in Single Stalls

    Directory of Open Access Journals (Sweden)

    Barbara Padalino

    2014-01-01

    Full Text Available The aim of this study was to investigate the impacts of three different physical exercises on the physiological and behavioural patterns of Standardbred trotters housed in single stalls. Twelve racing mares were observed twice during each different exercise: daily training (DT consisted of forty minutes at slow trot (4-5 m/s in a small track; maximal exercise (ME consisted of 1600 m run at maximal velocity; race (R was a real race of 1600 m. The mares were examined at rest in their stall (Time I, soon after the completion of the exercise (Time II, one hour (Time III, and two hours (Time IV after the exercise. Their heart rate, respiratory rate, and rectal temperature were recorded and they were videotaped in order to complete a focal animal sampling ethogram. All physiological parameters increased after exercise, in accordance with its intensity. After R and ME horses spent more time drinking, eating, and standing. The incidence of abnormal behaviours was very low and it was not affected by the different types of exercise. Overall, the assessment of horse behaviour after physical exercise by means of a focal animal sampling ethogram represents a useful tool to monitor equine welfare.

  1. An archival analysis of stall warning system effectiveness during airborne icing encounters

    Science.gov (United States)

    Maris, John Michael

    An archival study was conducted to determine the influence of stall warning system performance on aircrew decision-making outcomes during airborne icing encounters. A Conservative Icing Response Bias (CIRB) model was developed to explain the historical variability in aircrew performance in the face of airframe icing. The model combined Bayes' Theorem with Signal Detection Theory (SDT) concepts to yield testable predictions that were evaluated using a Binary Logistic Regression (BLR) multivariate technique applied to two archives: the NASA Aviation Safety Reporting System (ASRS) incident database, and the National Transportation Safety Board (NTSB) accident databases, both covering the period January 1, 1988 to October 2, 2015. The CIRB model predicted that aircrew would experience more incorrect response outcomes in the face of missed stall warnings than with stall warning False Alarms. These predicted outcomes were observed at high significance levels in the final sample of 132 NASA/NTSB cases. The CIRB model had high sensitivity and specificity, and explained 71.5% (Nagelkerke R2) of the variance of aircrew decision-making outcomes during the icing encounters. The reliability and validity metrics derived from this study suggest indicate that the findings are generalizable to the population of U.S. registered turbine-powered aircraft. These findings suggest that icing-related stall events could be reduced if the incidence of stall warning Misses could be minimized. Observed stall warning Misses stemmed from three principal causes: aerodynamic icing effects, which reduced the stall angle-of-attack (AoA) to below the stall warning calibration threshold; tail stalls, which are not monitored by contemporary protection systems; and icing-induced system issues (such as frozen pitot tubes), which compromised stall warning system effectiveness and airframe envelope protections. Each of these sources of missed stall warnings could be addressed by Aerodynamic Performance

  2. Stall Margin Improvement in a Centrifugal Compressor through Inducer Casing Treatment

    Directory of Open Access Journals (Sweden)

    V. V. N. K. Satish Koyyalamudi

    2016-01-01

    Full Text Available The increasing trend of high stage pressure ratio with increased aerodynamic loading has led to reduction in stable operating range of centrifugal compressors with stall and surge initiating at relatively higher mass flow rates. The casing treatment technique of stall control is found to be effective in axial compressors, but very limited research work is published on the application of this technique in centrifugal compressors. Present research was aimed to investigate the effect of casing treatment on the performance and stall margin of a high speed, 4 : 1 pressure ratio centrifugal compressor through numerical simulations using ANSYS CFX software. Three casing treatment configurations were developed and incorporated in the shroud over the inducer of the impeller. The predicted performance of baseline compressor (without casing treatment was in good agreement with published experimental data. The compressor with different inducer casing treatment geometries showed varying levels of stall margin improvement, up to a maximum of 18%. While the peak efficiency of the compressor with casing treatment dropped by 0.8%–1% compared to the baseline compressor, the choke mass flow rate was improved by 9.5%, thus enhancing the total stable operating range. The inlet configuration of the casing treatment was found to play an important role in stall margin improvement.

  3. An airloads theory for morphing airfoils in dynamic stall with experimental correlation

    Science.gov (United States)

    Ahaus, Loren A.

    Helicopter rotor blades frequently encounter dynamic stall during normal flight conditions, limiting the applicability of classical thin-airfoil theory at large angles of attack. Also, it is evident that because of the largely different conditions on the advancing and retreating sides of the rotor, future rotorcraft may incorporate dynamically morphing airfoils (trailing-edge aps, dynamic camber, dynamic droop, etc.). Reduced-order aerodynamic models are needed for preliminary design and ight simulation. A unified model for predicting the airloads on a morphing airfoil in dynamic stall is presented, consisting of three components. First, a linear airloads theory allows for arbitrary airfoil deformations consistent with a morphing airfoil. Second, to capture the effects of the wake, the airloads theory is coupled to an induced ow model. Third, the overshoot and time delay associated with dynamic stall are modeled by a second-order dynamic filter, along the lines of the ONERA dynamic stall model. This paper presents a unified airloads model that allows arbitrary airfoil morphing with dynamic stall. Correlations with experimental data validate the theory.

  4. A time-varying subjective quality model for mobile streaming videos with stalling events

    Science.gov (United States)

    Ghadiyaram, Deepti; Pan, Janice; Bovik, Alan C.

    2015-09-01

    Over-the-top mobile video streaming is invariably influenced by volatile network conditions which cause playback interruptions (stalling events), thereby impairing users' quality of experience (QoE). Developing models that can accurately predict users' QoE could enable the more efficient design of quality-control protocols for video streaming networks that reduce network operational costs while still delivering high-quality video content to the customers. Existing objective models that predict QoE are based on global video features, such as the number of stall events and their lengths, and are trained and validated on a small pool of ad hoc video datasets, most of which are not publicly available. The model we propose in this work goes beyond previous models as it also accounts for the fundamental effect that a viewer's recent level of satisfaction or dissatisfaction has on their overall viewing experience. In other words, the proposed model accounts for and adapts to the recency, or hysteresis effect caused by a stall event in addition to accounting for the lengths, frequency of occurrence, and the positions of stall events - factors that interact in a complex way to affect a user's QoE. On the recently introduced LIVE-Avvasi Mobile Video Database, which consists of 180 distorted videos of varied content that are afflicted solely with over 25 unique realistic stalling events, we trained and validated our model to accurately predict the QoE, attaining standout QoE prediction performance.

  5. Planter unit test stand

    Science.gov (United States)

    A planter test stand was developed to evaluate individual row-crop metering units in early 2013. This test stand provided the ability to quantify actual seed metering in terms of population, seed spacing, skips, and multiples over a range of meter RPMs and vacuum pressures. Preliminary data has been...

  6. The role of tip clearance in high-speed fan stall

    Energy Technology Data Exchange (ETDEWEB)

    Adamczyk, J.J. (NASA Lewis Research Center, Cleveland, OH (United States)); Celestina, M.L. (Sverdrup Tech., Inc., Cleveland, OH (United States)); Greitzer, E.M. (Massachusetts Institute of Technology, Cambridge, MA (United States))

    1993-01-01

    A numerical experiment has been carried out to define the near-stall casing endwall flow field of a high-speed fan rotor. The experiment used a simulation code incorporating a simple clearance model, whose calibration is presented. The results of the simulation show that the interaction of the tip leakage vortex and the in-passage shock plays a major role in determining the fan flow range. More specifically, the computations imply that it is the area increase of this vortex as it passes through the in-passage shock that is the source of the blockage associated with stall. In addition, for fans of this type, it is the clearance over the forward portion of the fan blade that controls the flow processes leading to stall.

  7. The role of tip clearance in high-speed fan stall

    Science.gov (United States)

    Adamczyk, J. J.; Celestina, M. L.; Greitzer, E. M.

    1991-01-01

    A numerical experiment has been carried out to define the near-stall casing endwall flowfield of a high-speed fan rotor. The experiment used a simulation code incorporating a simple clearance model, whose calibration is presented. The results of the simulation show that the interaction of the tip leakage vortex and the in-pasage shock plays a major role in determining the fan flow range. More specifically, the computations imply that it is the area increase of this vortex as it passes through the in-passage shock, which is the source of the blockage associated with stall. In addition, for fans of this type, it is the clearance over the forward portion of the fan blade which controls the flow processes leading to stall.

  8. Effect of summer grazing on welfare of dairy cows reared in mountain tie-stall barns

    Directory of Open Access Journals (Sweden)

    Simonetta Dovier

    2010-09-01

    Full Text Available Traditional mountain farms have an important economic, social and environmental role. The Alps management system for dairy cows consists of animals kept indoors from autumn to spring, mostly in tie-stalls, and moved to mountain pasture in summer. The aim of our study was to assess the effect of mountain summer grazing on the welfare of dairy cows housed in tie-stall barns. Twenty-four farms were considered. In twelve of them, animals were reared in tie-stalls and moved to mountain pasture for three months in summer; they were visited three times: (i four weeks before grazing during the indoor period in the stall; (ii about three weeks after the start of grazing; and (iii in the stall, in autumn, at least three weeks after returning from grazing. The other twelve farms kept the animals in tie-stalls all year; they were visited once in autumn. Data were collected following a protocol that considers animal-based measures and structure information on the basis of Quality Welfare Consortium® indications. Data allowed the calculation of both the Animal Needs Index score (ANI 35L and an overall assessment of the cows’ welfare obtained from three general aspects: housing, animal’s physical condition, and animal’s behaviour. Summer grazing had a significant positive effect on injuries, lameness and animal’s rising duration but a negative effect on faeces consistency. Moreover, a reduction of tongue playing was observed. The ANI 35L and the overall assessment did not show significant differences linked to summer grazing, which tended to have a positive but temporary effect on animal behaviour.

  9. Prediction of RNA Polymerase II recruitment, elongation and stalling from histone modification data

    DEFF Research Database (Denmark)

    Chen, Yun; Jørgensen, Mette; Kolde, Raivo

    2011-01-01

    strategies are needed to progress from descriptive annotation of data to quantitative, predictive models. RESULTS: Here, we describe a computational framework which with high accuracy can predict the locations of core promoters, the amount of recruited RNAPII at the promoter, the amount of elongating RNAPII...... of RNAPII stalling. CONCLUSIONS: In this study we introduce a general framework to accurately predict the level of RNAPII recruitment, elongation, stalling and mRNA expression from chromatin signals. The versatility of the method also makes it ideally suited to investigate other genomic data....

  10. Analysis of compressible light dynamic stall flow at transitional Reynolds numbers

    DEFF Research Database (Denmark)

    Dyken, R.D. Van; Ekaterinaris, John A.; Chandrasekhara, M.S.

    1996-01-01

    Numerical and experimental results of steady and light dynamic stall flow over an oscillating NACA 0012 airfoil at a freestream Mach number of 0.3 and Reynolds number of 0.54 x 10(6) are compared, The experimental observation that dynamic stall is induced from the bursting of a laminar separation...... point is specified suitably and a simple transition length model is incorporated to determine the extent of the laminar separation bubble. The thin-layer approximations of compressible, Reynolds-averaged, Navier-Stokes equations are used for the numerical solution, with an implicit, upwind-biased, third...

  11. Diagnosis of voltage collapse due to induction motor stalling using static analysis

    International Nuclear Information System (INIS)

    Karbalaei, F.; Kalantar, M.; Kazemi, A.

    2008-01-01

    Induction motor stalling is one of the important reasons for voltage collapse. This paper presents that, for induction motor stalling diagnosis, it is not necessary to use a third or first order dynamic model of induction motors. Instead, a method is presented based on algebraic calculations for which the steady state model of the induction motor considering different kinds of mechanical loads (constant and variable torque) is added to the power flow equations. Simulation results for a simple system confirm the correctness of the proposed method as compared to dynamic simulation results

  12. Power control of a wind farm with active stall wind turbines and AC grid connection

    DEFF Research Database (Denmark)

    Hansen, Anca Daniela; Sørensen, Poul; Iov, Florin

    This paper describes the design of a centralised wind farm controller for a wind farm made-up exclusively of active stall wind turbines with AC grid connection. The overall aim of such controller is to enable the wind farms to provide the best grid support. The designed wind farm control involves...... both the control on wind turbine level as well as the central control on the wind farm level. The ability of active stall wind farms with AC grid connection to regulate the power production to the reference power ordered by the operators is assessed and discussed by means of simulations....

  13. Kids, Schools, & Health--Where Do We Stand? Results of the New Mexico 1991 Youth Risk Behavior and 1992 School Health Surveys.

    Science.gov (United States)

    Utah Univ., Salt Lake City. Health Education Dept.

    This report describes the results of two statewide surveys: (1) The 1991 Youth Risk Behavior Survey; and (2) The 1992 New Mexico School Health Education Survey. These findings are intended to be used by educators across New Mexico to help focus the development of effective school-based comprehensive health education programs. Childrens' health…

  14. Jordan's 2002 to 2012 Fertility Stall and Parallel USAID Investments in Family Planning: Lessons From an Assessment to Guide Future Programming.

    Science.gov (United States)

    Spindler, Esther; Bitar, Nisreen; Solo, Julie; Menstell, Elizabeth; Shattuck, Dominick

    2017-12-28

    Health practitioners, researchers, and donors are stumped about Jordan's stalled fertility rate, which has stagnated between 3.7 and 3.5 children per woman from 2002 to 2012, above the national replacement level of 2.1. This stall paralleled United States Agency for International Development (USAID) funding investments in family planning in Jordan, triggering an assessment of USAID family planning programming in Jordan. This article describes the methods, results, and implications of the programmatic assessment. Methods included an extensive desk review of USAID programs in Jordan and 69 interviews with reproductive health stakeholders. We explored reasons for fertility stagnation in Jordan's total fertility rate (TFR) and assessed the effects of USAID programming on family planning outcomes over the same time period. The assessment results suggest that the increased use of less effective methods, in particular withdrawal and condoms, are contributing to Jordan's TFR stall. Jordan's limited method mix, combined with strong sociocultural determinants around reproduction and fertility desires, have contributed to low contraceptive effectiveness in Jordan. Over the same time period, USAID contributions toward increasing family planning access and use, largely focused on service delivery programs, were extensive. Examples of effective initiatives, among others, include task shifting of IUD insertion services to midwives due to a shortage of female physicians. However, key challenges to improved use of family planning services include limited government investments in family planning programs, influential service provider behaviors and biases that limit informed counseling and choice, pervasive strong social norms of family size and fertility, and limited availability of different contraceptive methods. In contexts where sociocultural norms and a limited method mix are the dominant barriers toward improved family planning use, increased national government investments

  15. Validation of the Beddoes-Leishman Dynamic Stall Model for Horizontal Axis Wind Turbines using MEXICO data

    NARCIS (Netherlands)

    Pereira, R.; Schepers, G.; Pavel, M.D.

    2011-01-01

    The aim of this study is to assess the load predicting capability of a classical Beddoes-Leishman dynamic stall model in a horizontal axis wind turbine (HAWT) environment, in the presence of yaw-misalignment. The dynamic stall model was tailored to the HAWT environment, and validated against

  16. Variable Attitude Test Stand

    Data.gov (United States)

    Federal Laboratory Consortium — The Variable Attitude Test Stand designed and built for testing of the V-22 tilt rotor aircraft propulsion system, is used to evaluate the effect of aircraft flight...

  17. A stochastic model for the simulation of wind turbine blades in static stall

    DEFF Research Database (Denmark)

    Bertagnolio, Franck; Rasmussen, Flemming; Sørensen, Niels N.

    2010-01-01

    The aim of this work is to improve aeroelastic simulation codes by accounting for the unsteady aerodynamic forces that a blade experiences in static stall. A model based on a spectral representation of the aerodynamic lift force is defined. The drag and pitching moment are derived using...

  18. Physics of Prestall Propagating Disturbances in Axial Compressors and Their Potential as a Stall Warning Indicator

    Directory of Open Access Journals (Sweden)

    Mario Eck

    2017-03-01

    Full Text Available Axial compressors in aero engines are prone to suffering a breakdown of orderly flow when operating at the peak of the pressure rise characteristic. The damaging potential of separated flows is why a safe distance has to be left between every possible operating point and an operating point at which stall occurs. During earlier investigations of stall inception mechanisms, a new type of prestall instability has been found. In this study, it could be demonstrated that the prestall instability characterised by discrete flow disturbances can be clearly assigned to the subject of “Rotating Instabilities”. Propagating disturbances are responsible for the rise in blade passing irregularity. If the mass flow is reduced successively, the level of irregularity increases until the prestall condition devolves into rotating stall. The primary objective of the current work is to highlight the basic physics behind these prestall disturbances by complementary experimental and numerical investigations. Before reaching the peak of the pressure rise characteristic flow, disturbances appear as small vortex tubes with one end attached to the casing and the other attached to the suction surface of the rotor blade. These vortex structures arise when the entire tip region is affected by blockage and at the same time the critical rotor incidence is not exceeded in this flow regime. Furthermore, a new stall indicator was developed by applying statistical methods to the unsteady pressure signal measured over the rotor blade tips, thus granting a better control of the safety margin.

  19. Numerical Study on the Acoustic Characteristics of an Axial Fan under Rotating Stall Condition

    Directory of Open Access Journals (Sweden)

    Lei Zhang

    2017-11-01

    Full Text Available Axial fan is an important piece of equipment in the thermal power plant that provides enough air for combustion of coal. This paper focuses on the aerodynamic noise characteristics of an axial fan in the development from stall inception to stall cells. The aerodynamic noise characteristic of monitoring region in time and frequency domains was simulated employing the large-eddy simulation (LES, with the addition of throttle setting and the Ffowcs Williams-Hawkings (FW-H noise model. The numerical results show that, under the design condition, the acoustic pressure presents regular periodicity along with the time. The noise energy is concentrated with high energy of the fundamental frequency and high order harmonics. During the stall inception stage, the acoustic pressure amplitude starts fluctuating and discrete frequencies are increased significantly in the low frequency; among them, there are three obvious discrete frequencies: 27.66 Hz, 46.10 Hz and 64.55 Hz. On the rotating stall condition, the fluctuation of the acoustic pressure level and amplitude are more serious than that mentioned above. During the whole evolution process, the acoustic pressure peak is difficult to keep stable all the time, and a sudden increase of the peak value at the 34.5th revolution corresponds to the relative velocity’s first sudden increase at the time when the valve coefficient is 0.780.

  20. Accounting for biases in riboprofiling data indicates a major role for proline in stalling translation.

    Science.gov (United States)

    Artieri, Carlo G; Fraser, Hunter B

    2014-12-01

    The recent advent of ribosome profiling-sequencing of short ribosome-bound fragments of mRNA-has offered an unprecedented opportunity to interrogate the sequence features responsible for modulating translational rates. Nevertheless, numerous analyses of the first riboprofiling data set have produced equivocal and often incompatible results. Here we analyze three independent yeast riboprofiling data sets, including two with much higher coverage than previously available, and find that all three show substantial technical sequence biases that confound interpretations of ribosomal occupancy. After accounting for these biases, we find no effect of previously implicated factors on ribosomal pausing. Rather, we find that incorporation of proline, whose unique side-chain stalls peptide synthesis in vitro, also slows the ribosome in vivo. We also reanalyze a method that implicated positively charged amino acids as the major determinant of ribosomal stalling and demonstrate that it produces false signals of stalling in low-coverage data. Our results suggest that any analysis of riboprofiling data should account for sequencing biases and sparse coverage. To this end, we establish a robust methodology that enables analysis of ribosome profiling data without prior assumptions regarding which positions spanned by the ribosome cause stalling. © 2014 Artieri and Fraser; Published by Cold Spring Harbor Laboratory Press.

  1. EVALUATION OF STYRENE EMISSIONS FROM A SHOWER STALL/BATHTUB MANUFACTURING FACILITY

    Science.gov (United States)

    The report gives results of emissions measurements carried out at a representative facility (Eljer Plumbingware in Wilson, NC) that manufactures polyester-resin-reinforced shower stalls and bathtubs by spraying styrene-based resins onto molds in vented, open, spray booths. Styren...

  2. 14 CFR 23.203 - Turning flight and accelerated turning stalls.

    Science.gov (United States)

    2010-01-01

    ... 14 Aeronautics and Space 1 2010-01-01 2010-01-01 false Turning flight and accelerated turning stalls. 23.203 Section 23.203 Aeronautics and Space FEDERAL AVIATION ADMINISTRATION, DEPARTMENT OF... a 30 degree bank. Reduce speed by steadily and progressively tightening the turn with the elevator...

  3. Power reduction and the radial limit of stall delay in revolving wings of different aspect ratio

    NARCIS (Netherlands)

    Kruyt, J.W.; Heijst, Van G.F.; Altshuler, D.L.; Lentink, David

    2015-01-01

    Airplanes and helicopters use high aspect ratio wings to reduce the power required to fly, but must operate at low angle of attack to prevent flow separation and stall. Animals capable of slow sustained flight, such as hummingbirds, have low aspect ratio wings and flap their wings at high angle

  4. Vortical structures responsible for delayed stall in an idealized humpback whale flipper model

    Science.gov (United States)

    Kim, Heesu; Kim, Jooha; Choi, Haecheon

    2016-11-01

    In this study, we investigate how the tubercles on the leading edge of an idealized humpback whale flipper model delay the stall. Oil-surface visualization is performed to see the surface flow pattern on the suction surface, and PIV is conducted in several streamwise and crossflow planes at different attack angles (α). Without tubercles, leading edge separation first occurs near the tip region and progresses inboard with increasing α. With tubercles, however, two types of vortical motions are observed at the mid-span. The first is streamwise vortex arrays which are dominant at α 9° , and these structures appear near the trailing edge. These two types of vortical motions delay flow separation at the peak regions of the mid-span, eliminating the spanwise stall progression and resulting in delayed stall. At α = 16° at which the tubercle model stalls, a large-scale streamwise vortex is originated from flow separation near the root region. This structure delays flow separation at the mid-span, leading to higher lift coefficient. Supported by NRF-2014M3C1B1033848.

  5. Identification of phlebovirus and arenavirus RNA sequences that stall and repress the exoribonuclease XRN1.

    Science.gov (United States)

    Charley, Phillida A; Wilusz, Carol J; Wilusz, Jeffrey

    2018-01-05

    Regulated mRNA decay plays a vital role in determining both the level and quality of cellular gene expression. Viral RNAs must successfully evade this host RNA decay machinery to establish a productive infection. One way for RNA viruses to accomplish this is to target the cellular exoribonuclease XRN1, because this enzyme is accessible in the cytoplasm and plays a major role in mRNA decay. Members of the Flaviviridae use RNA structures in their 5'- or 3'-untranslated regions to stall and repress XRN1, effectively stabilizing viral RNAs while also causing significant dysregulation of host cell mRNA stability. Here, we use a series of biochemical assays to demonstrate that the 3'-terminal portion of the nucleocapsid (N) mRNA of Rift Valley fever virus, a phlebovirus of the Bunyaviridae family, also can effectively stall and repress XRN1. The region responsible for impeding XRN1 includes a G-rich portion that likely forms a G-quadruplex structure. The 3'-terminal portions of ambisense-derived transcripts of multiple arenaviruses also stalled XRN1. Therefore, we conclude that RNAs from two additional families of mammalian RNA viruses stall and repress XRN1. This observation. emphasizes the importance and commonality of this viral strategy to interfere with the 5'-to-3'-exoribonuclease component of the cytoplasmic RNA decay machinery. © 2018 by The American Society for Biochemistry and Molecular Biology, Inc.

  6. Theory/test correlation of helicopter rotor blade element airloads in the blade stall regime

    Science.gov (United States)

    Bobo, C. J.

    1972-01-01

    The effects of stall on a rotor blade element in a three-dimensional rotating environment was investigated. The model rotor test provided blade element airloads and local boundary layer flow characteristics at the three-quarter blade radius position for a wide range of rotor operating conditions. A description of the test program and the test results are presented.

  7. Field rotor measurements. Data sets prepared for analysis of stall hysteresis

    Energy Technology Data Exchange (ETDEWEB)

    Aagaard Madsen, H.; Thirstrup Petersen, J. [Risoe National Lab. (Denmark); Bruining, A. [Delft Univ. of Technology (Netherlands); Brand, A. [ECN (Netherlands); Graham, M. [Imperical College (United Kingdom)

    1998-05-01

    As part of the JOULE-3 project `STALLVIB` an analysis and synthesis of the data from the field rotor experiments at ECN, Delft University, Imperial College, NREL and Risoe has been carried out. This has been done in order to see to what extent the data could be used for further development and validation of engineering dynamic stall models. A detailed investigation of the influence of the post-processing of the different data sets has been performed. Further, important statistical functions such as PSD spectra, coherence and transfer functions have been derived for the data sets which can be used as basis for evaluation of the quality of the data seen relative to actual application of the data. The importance of using an appropriate low-pass filtering to remove high frequency noise has been demonstrated when the relation between instantaneous values of e.g. {alpha} and C{sub N} is considered. In general, the complicated measurement on a rotor of {alpha} and w and the interpretation of these parameters combined with the strongly three-dimensional, turbulent flow field around the rotating blade has the consequence that it seems difficult to derive systematic information from the different data sets about stall hysteresis. In particular, the measurement of {alpha}, which determination of the stagnation point gives reasonable data below stall but fails in stall. On the other hand, measurements of {alpha} with a five hole pitot tube can be used also in the stall region. Another main problem is the non-dimensionalization of the coefficients C{sub N} and C{sub r}. If the dynamic pressure used for the non-dimensionalization is not fully correlated with the aerodynamic pressure over the considered airfoil section due to e.g. influence of the gravity on the pressure pipes, the hysteresis loops will be distorted. However, using the data with caution and applying a suitable post-processing as described by the different participants, it will probably be possible to obtain some

  8. Modeling dynamic stall on wind turbine blades under rotationally augmented flow fields

    Energy Technology Data Exchange (ETDEWEB)

    Guntur, S. [National Renewable Energy Laboratory (NREL), Golden, CO (United States); Schreck, S. [National Renewable Energy Laboratory (NREL), Golden, CO (United States); Sorensen, N. N. [Technical Univ. of Denmark, Lyngby (Denmark); Bergami, L. [Technical Univ. of Denmark, Lyngby (Denmark)

    2015-04-22

    It is well known that airfoils under unsteady flow conditions with a periodically varying angle of attack exhibit aerodynamic characteristics different from those under steady flow conditions, a phenomenon commonly known as dynamic stall. It is also well known that the steady aerodynamic characteristics of airfoils in the inboard region of a rotating blade differ from those under steady two-dimensional (2D) flow conditions, a phenomenon commonly known as rotational augmentation. This paper presents an investigation of these two phenomena together in the inboard parts of wind turbine blades. This analysis is carried out using data from three sources: (1) the National Renewable Energy Laboratory’s Unsteady Aerodynamics Experiment Phase VI experimental data, including constant as well as continuously pitching blade conditions during axial operation, (2) data from unsteady Delayed Detached Eddy Simulations (DDES) carried out using the Technical University of Denmark’s in-house flow solver Ellipsys3D, and (3) data from a simplified model based on the blade element momentum method with a dynamic stall subroutine that uses rotationally augmented steady-state polars obtained from steady Phase VI experimental sequences, instead of the traditional 2D nonrotating data. The aim of this work is twofold. First, the blade loads estimated by the DDES simulations are compared to three select cases of the N sequence experimental data, which serves as a validation of the DDES method. Results show reasonable agreement between the two data in two out of three cases studied. Second, the dynamic time series of the lift and the moment polars obtained from the experiments are compared to those from the dynamic stall subroutine that uses the rotationally augmented steady polars. This allowed the differences between the stall phenomenon on the inboard parts of harmonically pitching blades on a rotating wind turbine and the classic dynamic stall representation in 2D flow to be

  9. Parametric analyses on dynamic stall control of rotor airfoil via synthetic jet

    Directory of Open Access Journals (Sweden)

    Qijun ZHAO

    2017-12-01

    Full Text Available The effects of synthetic jet control on unsteady dynamic stall over rotor airfoil are investigated numerically. A moving-embedded grid method and an Unsteady Reynolds Averaged Navier-Stokes (URANS solver coupled with k-ω Shear Stress Transport (SST turbulence model are established for predicting the complex flowfields of oscillatory airfoil under jet control. Additionally, a velocity boundary condition modeled by sinusoidal function has been developed to fulfill the perturbation effect of periodic jet. The validity of present CFD method is evaluated by comparisons of the calculated results of baseline dynamic stall case for rotor airfoil and jet control case for VR-7B airfoil with experimental data. Then, parametric analyses are conducted emphatically for an OA212 rotor airfoil to investigate the effects of jet control parameters (jet location, dimensionless frequency, momentum coefficient, jet angle, jet type and dual-jet on dynamic stall characteristics of rotor airfoil. It is demonstrated by the calculated results that efficiency of jet control could be improved with specific momentum coefficient and jet angle when the jet is located near separation point of rotor airfoil. Furthermore, the dual-jet could improve control efficiency more obviously on dynamic stall of rotor airfoil with respect to the unique jet, and the influence laws of dual-jet’s angles and momentum coefficients on control effects are similar to those of the unique jet. Finally, unsteady aerodynamic characteristics of rotor via synthetic jet which is located on the upper surface of rotor blade in forward flight are calculated, and as a result, the aerodynamic characteristics of rotor are improved compared with the baseline. The results indicate that synthetic jet has the capability in improving aerodynamic characteristics of rotor. Keywords: Airfoil, Dynamic stall characteristics, Flow control, Moving-embedded grid methodology, Navier-Stokes equations, Parametric

  10. Power reduction and the radial limit of stall delay in revolving wings of different aspect ratio.

    Science.gov (United States)

    Kruyt, Jan W; van Heijst, GertJan F; Altshuler, Douglas L; Lentink, David

    2015-04-06

    Airplanes and helicopters use high aspect ratio wings to reduce the power required to fly, but must operate at low angle of attack to prevent flow separation and stall. Animals capable of slow sustained flight, such as hummingbirds, have low aspect ratio wings and flap their wings at high angle of attack without stalling. Instead, they generate an attached vortex along the leading edge of the wing that elevates lift. Previous studies have demonstrated that this vortex and high lift can be reproduced by revolving the animal wing at the same angle of attack. How do flapping and revolving animal wings delay stall and reduce power? It has been hypothesized that stall delay derives from having a short radial distance between the shoulder joint and wing tip, measured in chord lengths. This non-dimensional measure of wing length represents the relative magnitude of inertial forces versus rotational accelerations operating in the boundary layer of revolving and flapping wings. Here we show for a suite of aspect ratios, which represent both animal and aircraft wings, that the attachment of the leading edge vortex on a revolving wing is determined by wing aspect ratio, defined with respect to the centre of revolution. At high angle of attack, the vortex remains attached when the local radius is shorter than four chord lengths and separates outboard on higher aspect ratio wings. This radial stall limit explains why revolving high aspect ratio wings (of helicopters) require less power compared with low aspect ratio wings (of hummingbirds) at low angle of attack and vice versa at high angle of attack. © 2015 The Author(s) Published by the Royal Society. All rights reserved.

  11. The ribosome quality control pathway can access nascent polypeptides stalled at the Sec61 translocon.

    Science.gov (United States)

    von der Malsburg, Karina; Shao, Sichen; Hegde, Ramanujan S

    2015-06-15

    Cytosolic ribosomes that stall during translation are split into subunits, and nascent polypeptides trapped in the 60S subunit are ubiquitinated by the ribosome quality control (RQC) pathway. Whether the RQC pathway can also target stalls during cotranslational translocation into the ER is not known. Here we report that listerin and NEMF, core RQC components, are bound to translocon-engaged 60S subunits on native ER membranes. RQC recruitment to the ER in cultured cells is stimulated by translation stalling. Biochemical analyses demonstrated that translocon-targeted nascent polypeptides that subsequently stall are polyubiquitinated in 60S complexes. Ubiquitination at the translocon requires cytosolic exposure of the polypeptide at the ribosome-Sec61 junction. This exposure can result from either failed insertion into the Sec61 channel or partial backsliding of translocating nascent chains. Only Sec61-engaged nascent chains early in their biogenesis were relatively refractory to ubiquitination. Modeling based on recent 60S-RQC and 80S-Sec61 structures suggests that the E3 ligase listerin accesses nascent polypeptides via a gap in the ribosome-translocon junction near the Sec61 lateral gate. Thus the RQC pathway can target stalled translocation intermediates for degradation from the Sec61 channel. © 2015 von der Malsburg et al. This article is distributed by The American Society for Cell Biology under license from the author(s). Two months after publication it is available to the public under an Attribution–Noncommercial–Share Alike 3.0 Unported Creative Commons License (http://creativecommons.org/licenses/by-nc-sa/3.0).

  12. Armillaria species in coniferous stands

    Directory of Open Access Journals (Sweden)

    Anna Żółciak

    2013-12-01

    Full Text Available Identification of the Armillaria species in selected coniferous stands (Scots pine stands, Norway spruce stands and fir stands was the aim of the work carried out on the basis of mating tests and consideration of macroscopic traits of fruit-bodies. One species of Armillaria [A. ostoyae (Romagnesi Herink] was found in Scots pine stands, three species [A. ostoyae, A. cepistipes Velenovský and A. borealis Marxmüller et Korhonen] were found in Norway spruce stands and two species [A. ostoyae and A. cepistipes] were found in fir stands.

  13. Investigation of the wind climate in connection with double-stall on wind turbines in Tarifa[Spain]; Undersoegelse af vindklima i forbindelse med dobbelt-stall paa vindmoeller i Tarifa

    Energy Technology Data Exchange (ETDEWEB)

    Christensen, T. [ELSAMPROJEKT A/S, Fredericia, (Denmark); Jensen, L.E. [LM Glasfiber A/S, Lunderskov (Denmark)

    2000-08-01

    This project has compiled data to allow the Danish manufacturers of wind turbines and blades to improve their knowledge of double stall. On the basis of the double stall difficulties different types of turbines using different makes of blades have encountered in the Tarifa area in Southern Spain, meteorological parameters and production data from two turbines have been measured for a local site. Part of the acquired data have been analysed to reach an understanding of why double stall occurs. The analysis strongly suggests that a change in power level due to double stall can be a result of several external factors: (1) Rain cleaning the blades. (2) A more or less random change in the wind speed components uv, or w, which in some cases can affect a - probably - fairly thick boundary layer. (3) A change in the high frequency turbulence where the vortex impact is too insignificant to affect an - almost - randomly - thick boundary layer. (au)

  14. Golden rule (standing theology)

    OpenAIRE

    Ellis, Randolph

    2017-01-01

    This study offers an example of ‘standing theology’ as distinguished from sitting theology or kneeling theology. The occasion was the Fourth Sunday of Easter in Bangor Cathedral, 2015. The Epistle reading was 1 John 3: 16–24.\\ud \\ud

  15. Economics of stand management

    Science.gov (United States)

    David K. Lewis

    1986-01-01

    This paper sets out to demonstrate the importance of considering the wealth represented by the growing stock in economic analyses of stand management alternatives, and to demonstrate the role of thinning in the manipulation of the efficiency of growing stock in the management of shortleaf pine (Pinus echinata Mill.). These goals are achieved through a demonstration of...

  16. Principles of managing stands

    Science.gov (United States)

    David A. Marquis; Rodney Jacobs

    1989-01-01

    Forest stands are managed to achieve some combination of desired products or values. These products or values may include income and tangible benefits from timber production or fees for hunting rights and other recreational activities. The values may be intangible, such as the enjoyment of seeing wildlife or flowering plants, or the simple satisfaction of knowing that...

  17. Why Do Promising Therapies Stall in Development and How Can We Move Them Forward?

    Science.gov (United States)

    Wegner, Craig D; Goodwin, Andrew; Cook, Jon C; Allamneni, Krishna; Sohn, Jane; McVean, Maralee

    There are many reasons that molecules fail to progress to market and various principles of risk-benefit decisions that can help drive the molecule through development. This symposium included discussions on global strategies involved in pushing promising molecules to market, what to do when a molecule stalls in its progress to market, and options for rescuing the molecule and pushing it forward again. Innovative partnerships that bring stalled drugs back into clinical development were also addressed. A regulatory perspective on common reasons for a molecule to fail in its forward progress was presented. In addition, situations arise when a third-party advisory committee can provide input to help overcome issues identified by a regulatory agency. Using examples from the private and public domain, presentations centered on how to repurpose a molecule and when more science is needed.

  18. Grid support of a wind farm with active stall wind turbines and AC grid connection

    DEFF Research Database (Denmark)

    Hansen, Anca Daniela; Sørensen, Poul Ejnar; Iov, F.

    2006-01-01

    grid connection. The designed control system has the task of enabling such a wind farm to provide the best grid support. It is based on two control levels: a supervisory control level, which controls the power production of the whole farm by sending out reference signals to each individual wind turbine......, and a local control level, which ensures that the reference power signals at the wind turbine level are reached. The ability of active stall wind farms with AC grid connection to control the power production to the reference power ordered by the operators is assessed and discussed by means of simulations.......One of the main concerns in the grid integration of large wind farms is their ability to behave as active controllable components in the power system. This article presents the design of a new integrated power control system for a wind farm made up exclusively of active stall wind turbines with AC...

  19. Learning to Stand: The Acceptability and Feasibility of Introducing Standing Desks into College Classrooms

    Directory of Open Access Journals (Sweden)

    Roberto M. Benzo

    2016-08-01

    Full Text Available Prolonged sedentary behavior is an independent risk factor for multiple negative health outcomes. Evidence supports introducing standing desks into K-12 classrooms and work settings to reduce sitting time, but no studies have been conducted in the college classroom environment. The present study explored the acceptability and feasibility of introducing standing desks in college classrooms. A total of 993 students and 149 instructors completed a single online needs assessment survey. This cross-sectional study was conducted during the fall semester of 2015 at a large Midwestern University. The large majority of students (95% reported they would prefer the option to stand in class. Most students (82.7% reported they currently sit during their entire class time. Most students (76.6% and instructors (86.6% reported being in favor of introducing standing desks into college classrooms. More than half of students and instructors predicted having access to standing desks in class would improve student’s “physical health”, “attention”, and “restlessness”. Collectively, these findings support the acceptability of introducing standing desks in college classrooms. Future research is needed to test the feasibility, cost-effectiveness and efficacy of introducing standing desks in college classrooms. Such studies would be useful for informing institutional policies regarding classroom designs.

  20. Simulation model of a transient fault controller for an active-stall wind turbine

    Energy Technology Data Exchange (ETDEWEB)

    Jauch, C.; Soerensen, P.; Bak Jensen, B.

    2005-01-01

    This paper describes the simulation model of a controller that enables an active-stall wind turbine to ride through transient faults. The simulated wind turbine is connected to a simple model of a power system. Certain fault scenarios are specified and the turbine shall be able to sustain operation in case of such faults. The design of the controller is described and its performance assessed by simulations. The control strategies are explained and the behaviour of the turbine discussed. (author)

  1. DksA guards elongating RNA polymerase against ribosome-stalling-induced arrest.

    Science.gov (United States)

    Zhang, Yan; Mooney, Rachel A; Grass, Jeffrey A; Sivaramakrishnan, Priya; Herman, Christophe; Landick, Robert; Wang, Jue D

    2014-03-06

    In bacteria, translation-transcription coupling inhibits RNA polymerase (RNAP) stalling. We present evidence suggesting that, upon amino acid starvation, inactive ribosomes promote rather than inhibit RNAP stalling. We developed an algorithm to evaluate genome-wide polymerase progression independently of local noise and used it to reveal that the transcription factor DksA inhibits promoter-proximal pausing and increases RNAP elongation when uncoupled from translation by depletion of charged tRNAs. DksA has minimal effect on RNAP elongation in vitro and on untranslated RNAs in vivo. In these cases, transcripts can form RNA structures that prevent backtracking. Thus, the effect of DksA on transcript elongation may occur primarily upon ribosome slowing/stalling or at promoter-proximal locations that limit the potential for RNA structure. We propose that inactive ribosomes prevent formation of backtrack-blocking mRNA structures and that, in this circumstance, DksA acts as a transcription elongation factor in vivo. Copyright © 2014 Elsevier Inc. All rights reserved.

  2. An automatic system for the detection of dairy cows lying behaviour in free-stall barns

    Directory of Open Access Journals (Sweden)

    Simona M.C. Porto

    2013-09-01

    Full Text Available In this paper, a method for the automatic detection of dairy cow lying behaviour in free-stall barns is proposed. A computer visionbased system (CVBS composed of a video-recording system and a cow lying behaviour detector based on the Viola Jones algorithm was developed. The CVBS performance was tested in a head-to-head free stall barn. Two classifiers were implemented in the software component of the CVBS to obtain the cow lying behaviour detector. The CVBS was validated by comparing its detection results with those generated from visual recognition. This comparison allowed the following accuracy indices to be calculated: the branching factor (BF, the miss factor (MF, the sensitivity, and the quality percentage (QP. The MF value of approximately 0.09 showed that the CVBS missed one cow every 11 well detected cows. Conversely, the BF value of approximately 0.08 indicated that one false positive was detected every 13 well detected cows. The high value of approximately 0.92 obtained for the sensitivity index and that obtained for QP of about 0.85 revealed the ability of the proposed system to detect cows lying in the stalls.

  3. Piloted Simulator Evaluation Results of Flight Physics Based Stall Recovery Guidance

    Science.gov (United States)

    Lombaerts, Thomas; Schuet, Stefan; Stepanyan, Vahram; Kaneshige, John; Hardy, Gordon; Shish, Kimberlee; Robinson, Peter

    2018-01-01

    In recent studies, it has been observed that loss of control in flight is the most frequent primary cause of accidents. A significant share of accidents in this category can be remedied by upset prevention if possible, and by upset recovery if necessary, in this order of priorities. One of the most important upsets to be recovered from is stall. Recent accidents have shown that a correct stall recovery maneuver remains a big challenge in civil aviation, partly due to a lack of pilot training. A possible strategy to support the flight crew in this demanding context is calculating a recovery guidance signal, and showing this signal in an intuitive way on one of the cockpit displays, for example by means of the flight director. Different methods for calculating the recovery signal, one based on fast model predictive control and another using an energy based approach, have been evaluated in four relevant operational scenarios by experienced commercial as well as test pilots in the Vertical Motion Simulator at NASA Ames Research Center. Evaluation results show that this approach could be able to assist the pilots in executing a correct stall recovery maneuver.

  4. The Relationships between Selection and Processing Food with Escherichia coli Contaminant on Food Stall Serving

    Directory of Open Access Journals (Sweden)

    Tris Eryando

    2014-04-01

    Full Text Available Escherichia coli in food stalls surrounding the X Campuss in Depok, year 2012. The research conducted to examine food safety, which were served in surrounding the campus X in Depok. Escherichia coli (E. coli existence was used to indicate the quality of hygiene and sanitation of the food that was served. Using the cross sectional method, the research examined the persons who served the food to be sold in the food stalls in the campus. There were 173 food servers chosen as the respondents from 10 different food stalls around the university. The existence of E. coli examined in the microbiology laboratory in the Faculty of Public Health. Using the most probable number (MPN method found that 59.54% of the food served in the campus were contaminated E. coli. Factors affecting the existence of E. coli were the raw materials (vegetables treated and the length of cooking of the materials (rice/beens. The improper treatment such as washing with no running water or even unwashed vegetables had 5 times risk of the E. coli contamination. Cooking less than 15 minutes was also more risky than cooking more than 15 minutes. As a result, this is very important to find a method to improve knowledge and to increase practical skills in food safety. Furthermore, in this research area may give contribution to avoid E. coli contamination which will prevent unnecessary illness among students in the campus.

  5. Replisome stall events have shaped the distribution of replication origins in the genomes of yeasts

    Science.gov (United States)

    Newman, Timothy J.; Mamun, Mohammed A.; Nieduszynski, Conrad A.; Blow, J. Julian

    2013-01-01

    During S phase, the entire genome must be precisely duplicated, with no sections of DNA left unreplicated. Here, we develop a simple mathematical model to describe the probability of replication failing due to the irreversible stalling of replication forks. We show that the probability of complete genome replication is maximized if replication origins are evenly spaced, the largest inter-origin distances are minimized, and the end-most origins are positioned close to chromosome ends. We show that origin positions in the yeast Saccharomyces cerevisiae genome conform to all three predictions thereby maximizing the probability of complete replication if replication forks stall. Origin positions in four other yeasts—Kluyveromyces lactis, Lachancea kluyveri, Lachancea waltii and Schizosaccharomyces pombe—also conform to these predictions. Equating failure rates at chromosome ends with those in chromosome interiors gives a mean per nucleotide fork stall rate of ∼5 × 10−8, which is consistent with experimental estimates. Using this value in our theoretical predictions gives replication failure rates that are consistent with data from replication origin knockout experiments. Our theory also predicts that significantly larger genomes, such as those of mammals, will experience a much greater probability of replication failure genome-wide, and therefore will likely require additional compensatory mechanisms. PMID:23963700

  6. Aire unleashes stalled RNA polymerase to induce ectopic gene expression in thymic epithelial cells.

    Science.gov (United States)

    Giraud, Matthieu; Yoshida, Hideyuki; Abramson, Jakub; Rahl, Peter B; Young, Richard A; Mathis, Diane; Benoist, Christophe

    2012-01-10

    Aire is a transcriptional regulator that induces expression of peripheral tissue antigens (PTA) in thymic medullary epithelial cells (MECs), driving immunological self-tolerance in differentiating T cells. To elucidate its mechanistic pathways, we examined its transcriptional impact in MECs in vivo by microarray analysis with mRNA-spanning probes. This analysis revealed initiation of Aire-activated genes to be comparable in Aire-deficient and wild-type MECs, but with a block to elongation after 50-100 bp in the absence of Aire, suggesting activation by release of stalled polymerases by Aire. In contrast, patterns of activation by transcription factors such as Klf4 were consistent with regulation of initiation. Mapping of Aire and RNA polymerase-II (Pol-II) by ChIP and high-throughput sequencing (ChIP-seq) revealed that Aire bound all Pol-II-rich transcriptional start sites (TSS), irrespective of its eventual effect. However, the genes it preferentially activated were characterized by a relative surfeit of stalled polymerases at the TSS, which resolved once Aire was introduced into cells. Thus, transcript mapping and ChIP-seq data indicate that Aire activates ectopic transcription not through specific recognition of PTA gene promoters but by releasing stalled polymerases.

  7. Short revolving wings enable hovering animals to avoid stall and reduce drag

    Science.gov (United States)

    Lentink, David; Kruyt, Jan W.; Heijst, Gertjan F.; Altshuler, Douglas L.

    2014-11-01

    Long and slender wings reduce the drag of airplanes, helicopters, and gliding animals, which operate at low angle of attack (incidence). Remarkably, there is no evidence for such influence of wing aspect ratio on the energetics of hovering animals that operate their wings at much higher incidence. High incidence causes aircraft wings to stall, hovering animals avoid stall by generating an attached vortex along the leading edge of their wings that elevates lift. Hypotheses that explain this capability include the necessity for a short radial distance between the shoulder joint and wing tip, measured in chord lengths, instead of the long tip-to-tip distance that elevates aircraft performance. This stems from how hovering animals revolve their wings around a joint, a condition for which the precise effect of aspect ratio on stall performance is unknown. Here we show that the attachment of the leading edge vortex is determined by wing aspect ratio with respect to the center of rotation-for a suite of aspect ratios that represent both animal and aircraft wings. The vortex remains attached when the local radius is shorter than 4 chord lengths, and separates outboard on more slender wings. Like most other hovering animals, hummingbirds have wing aspect ratios between 3 and 4, much stubbier than helicopters. Our results show this makes their wings robust against flow separation, which reduces drag below values obtained with more slender wings. This revises our understanding of how aspect ratio improves performance at low Reynolds numbers.

  8. Behavioral changes in female Asian elephants when given access to an outdoor yard overnight.

    Science.gov (United States)

    Powell, David M; Vitale, Cathy

    2016-07-01

    A study was conducted at the Bronx Zoo to determine whether providing elephants with access to an outdoor corral at night had any significant effects on behavior, use of space, and use of a sand corral. Activity budgets for three female Asian elephants were compared when the subjects were housed indoors overnight and when they were given access to an outdoor yard overnight. Observations were recorded via infrared video cameras between the hours of 1900 and 0700 during the months of July-September. Two of the three elephants showed a significant preference for spending time outdoors, whereas, the third elephant spent most of her time indoors. Standing and play behavior increased when the elephants had outdoor access while lying down and feeding behavior decreased. Swaying behavior decreased significantly when the elephants had access to the outdoor yard. The elephants made very little use of a sand-floor stall regardless of whether or not they had access to outdoors. The results of this study, suggest that having access to alternate areas overnight can promote well-being by reducing repetitive behavior and allowing animals to express their preferences for different locations. The relative importance of choice alone vs. the behavioral opportunities provided by choice options for zoo animals is discussed. Zoo Biol. 35:298-303, 2016. © 2016 Wiley Periodicals, Inc. © 2016 Wiley Periodicals, Inc.

  9. Take a Stand!

    DEFF Research Database (Denmark)

    Danquah, I. H.; Kloster, S.; Holtermann, A.

    2017-01-01

    Background: Prolonged sitting time has been associated with adverse health outcomes. Interventions at work may contribute to reduced sitting. The objective was to test if a multicomponent work-based intervention can reduce sitting time and the number of prolonged sitting periods (> 30 min......), increase the number of sit-to-stand transitions and decrease waist circumference and body fat percentage among office workers. Primary outcomes were: change in sitting time, prolonged sitting periods and sit-to-stand transitions at followup 1 month later. Methods: At four workplaces, 19 offices (317...... workers in total) were cluster randomized for intervention or control. The intervention included the appointment of local ambassadors, management support, environmental changes, a lecture and a workshop. Sitting time was measured using an ActiGraph GT3X+ fixed on the thigh. Data were processed using Acti4...

  10. Stand-alone XLIF

    DEFF Research Database (Denmark)

    Hansen, E. J.; Simony, A.; Hummel, Stefan

    2015-01-01

    and clinical/radiological results in 22 patients treated with XLIF procedure for DS or degenerative disc disease (DDD). Material and methods: 22 consecutive patients with DS underwent surgery with the XLIF stand-alone procedure, with follow-up of 24 months. Clinical outcome scores were collected. Complications......Introduction: Adult thoracolumbar degeneration is an increasing challenge in the aging population. With age the progressive degeneration of the discs leads to an asymmetric collapse and a thoracolumbar coronal plane deformity, a degenerative scoliosis (DS). Aim: To evaluate the complication rate......-year follow-up, with a 31.8% revision rate. Due to the high revision rate we recommend supplementary posterior instrumentation, to achieve a higher fusion rate. When considering XLIF-stand-alone procedure for DS or DDD without supplemental posterior instrumentation, only single-level disease should...

  11. Multi-Purpose Test Stand

    Data.gov (United States)

    Federal Laboratory Consortium — The Multi-Purpose Test Stand is used for a wide variety of tests. The Stand is designed to be rotated through a range of fixed yaw positions to allow engines to be...

  12. The effect of alphacypermethrin-treated mesh protection against African horse sickness virus vectors on jet stall microclimate, clinical variables and faecal glucocorticoid metabolites of horses.

    Science.gov (United States)

    Page, Patrick; Ganswindt, Andre; Schoeman, Johan; Venter, Gert; Guthrie, Alan

    2017-09-09

    African horse sickness (AHS) is of importance to health and international trade in horses worldwide. During export from and transit through AHS endemic countries or zones, physical and chemical measures to protect horses from the vectors of AHS virus (AHSV) are recommended by the World Organization for Animal Health. Protection of containerized air transport systems for horses (jet stalls) with alphacypermethrin insecticide-treated high density polyethylene mesh is effective in reducing the Culicoides midge vector attack rate. In order to determine the effect of this mesh on jet stall ventilation and horse welfare under temperate climatic conditions, jet stall microclimate, clinical variables and faecal glucocorticoid metabolite (FGM) levels of 12 horses were monitored during overnight housing in either a treated or untreated stall in two blocks of a 2 × 3 randomized crossover design. Temperature difference between the treated stall and outside was significantly higher than the difference between the untreated stall and outside at 1/15 time points only (P = 0.045, r = 0.70). Relative humidity (RH) difference between the treated stall and outside did not differ from the untreated stall and outside. Temperature and RH in the treated stall were highly and significantly correlated with outside temperature (r = 0.96, P < 0.001) and RH (r = 0.95, P < 0.001), respectively. No significant differences were detected between rectal temperatures, pulse and respiratory rates of horses in the treated stall compared to the untreated stall. Mean FGM concentrations for horses housed in the treated stall peaked earlier (24 h) and at a higher concentration than horses housed in the untreated stall (48 h), but were not significantly different from baseline. No significant difference was detected in FGM concentrations when the treated and untreated stall groups were compared at individual time points up to 72 h after exiting the jet stall. Alphacypermethrin

  13. Standing equine dental surgery.

    Science.gov (United States)

    Menzies, Robert A; Easley, Jack

    2014-04-01

    Dental surgeries refer to procedures that affect the dental tissues or their supporting structures. With the development of specific, efficacious, and conservative treatments, morbidity risks have been lowered and chances of benefiting the health of equids improved. Advances in quality of sedation, analgesia, and locoregional anesthesia allow a majority of dental surgeries to be performed in the standing patient. This update focuses on an orthograde endodontic technique, a minimally invasive buccotomy technique, with the potential to combine it with a transbuccal screw extraction technique, and revisits the AO pinless external fixator for fractures of the body of the mandible. Copyright © 2014 Elsevier Inc. All rights reserved.

  14. Standing down Straight: Jump Rhythm Technique's Rhythm-Driven, Community-Directed Approach to Dance Education

    Science.gov (United States)

    Siegenfeld, Billy

    2009-01-01

    "Standing down straight" means to stand on two feet with both stability and relaxation. Using standing down straight as the foundation of class work, Jump Rhythm Technique offers a fresh alternative to conventional systems of dance study. It bases its pedagogy on three behaviors: grounding the body so that it can move with power and efficiency,…

  15. Animal hygiene assessment of microclimate in semi open free-stall barns for dairy cows

    Directory of Open Access Journals (Sweden)

    D. Dimov

    2017-03-01

    Full Text Available Abstract. The study was conducted in three semi open free-stall barns (B1, B2, and B3 for dairy cows with capacities for 120, 120 and 500 cows, respectively, from three different dairy farms (F-1, F-2 and F-3, situated in Central Southern Bulgaria. The investigated farms had the same production system – loose housing in semi open free-stall dairy barn. For each of the farms the main microclimatic parameters – air temperature, relative humidity and speed of airflow were recorded twice a month at 10.00 h 12.00 h, 14.00 h, 16.00 h and 18.00 h of the day inside the barns in three main technological zones - above the stalls, above manure and feed alleys and outside the buildings. It was found that: a Microclimatic parameters (air temperature, air relative humidity and speed of airflow in technological zones (above the stalls, the manure and feed alleys of three semi open free-stall dairy barns meet the animal hygienic requirements for all seasons according to Regulation No. 44 (2006. Exceptions are some values of relative humidity in B1 and B2 in the spring, and in B1 in winter and summer, which are lower than the minimum humidity (50% according to the standard. b The investigated barns are characterized with poor insulation and do not provide enough isolation from the external ambient temperatures. With the exception of winter, the temperature of the air inside the buildings was lower than that outside, with minor differences for all seasons. The fans in the barns have no effect on the inside air temperature, especially in summer. There was a risk of higher temperatures mainly during the summer period. c There is no significant difference between the average temperatures, air humidity and speed of airflow in all technological zones of the investigated barns. d The largest and statistically significant is the difference between the relative air humidity outside and inside the building in Farm 3, followed by buildings in Farm 1 and 2, where the

  16. Prediction of RNA Polymerase II recruitment, elongation and stalling from histone modification data

    Science.gov (United States)

    2011-01-01

    Background Initiation and elongation of RNA polymerase II (RNAPII) transcription is regulated by both DNA sequence and chromatin signals. Recent breakthroughs make it possible to measure the chromatin state and activity of core promoters genome-wide, but dedicated computational strategies are needed to progress from descriptive annotation of data to quantitative, predictive models. Results Here, we describe a computational framework which with high accuracy can predict the locations of core promoters, the amount of recruited RNAPII at the promoter, the amount of elongating RNAPII in the gene body, the mRNA production originating from the promoter and finally also the stalling characteristics of RNAPII by considering both quantitative and spatial features of histone modifications around the transcription start site (TSS). As the model framework can also pinpoint the signals that are the most influential for prediction, it can be used to infer underlying regulatory biology. For example, we show that the H3K4 di- and tri- methylation signals are strongly predictive for promoter location while the acetylation marks H3K9 and H3K27 are highly important in estimating the promoter usage. All of these four marks are found to be necessary for recruitment of RNAPII but not sufficient for the elongation. We also show that the spatial distributions of histone marks are almost as predictive as the signal strength and that a set of histone marks immediately downstream of the TSS is highly predictive of RNAPII stalling. Conclusions In this study we introduce a general framework to accurately predict the level of RNAPII recruitment, elongation, stalling and mRNA expression from chromatin signals. The versatility of the method also makes it ideally suited to investigate other genomic data. PMID:22047616

  17. Prediction of RNA Polymerase II recruitment, elongation and stalling from histone modification data

    Directory of Open Access Journals (Sweden)

    Chen Yun

    2011-11-01

    Full Text Available Abstract Background Initiation and elongation of RNA polymerase II (RNAPII transcription is regulated by both DNA sequence and chromatin signals. Recent breakthroughs make it possible to measure the chromatin state and activity of core promoters genome-wide, but dedicated computational strategies are needed to progress from descriptive annotation of data to quantitative, predictive models. Results Here, we describe a computational framework which with high accuracy can predict the locations of core promoters, the amount of recruited RNAPII at the promoter, the amount of elongating RNAPII in the gene body, the mRNA production originating from the promoter and finally also the stalling characteristics of RNAPII by considering both quantitative and spatial features of histone modifications around the transcription start site (TSS. As the model framework can also pinpoint the signals that are the most influential for prediction, it can be used to infer underlying regulatory biology. For example, we show that the H3K4 di- and tri- methylation signals are strongly predictive for promoter location while the acetylation marks H3K9 and H3K27 are highly important in estimating the promoter usage. All of these four marks are found to be necessary for recruitment of RNAPII but not sufficient for the elongation. We also show that the spatial distributions of histone marks are almost as predictive as the signal strength and that a set of histone marks immediately downstream of the TSS is highly predictive of RNAPII stalling. Conclusions In this study we introduce a general framework to accurately predict the level of RNAPII recruitment, elongation, stalling and mRNA expression from chromatin signals. The versatility of the method also makes it ideally suited to investigate other genomic data.

  18. Replication Stalling and Heteroduplex Formation within CAG/CTG Trinucleotide Repeats by Mismatch Repair

    KAUST Repository

    Viterbo, David

    2016-03-16

    Trinucleotide repeat expansions are responsible for at least two dozen neurological disorders. Mechanisms leading to these large expansions of repeated DNA are still poorly understood. It was proposed that transient stalling of the replication fork by the repeat tract might trigger slippage of the newly-synthesized strand over its template, leading to expansions or contractions of the triplet repeat. However, such mechanism was never formally proven. Here we show that replication fork pausing and CAG/CTG trinucleotide repeat instability are not linked, stable and unstable repeats exhibiting the same propensity to stall replication forks when integrated in a yeast natural chromosome. We found that replication fork stalling was dependent on the integrity of the mismatch-repair system, especially the Msh2p-Msh6p complex, suggesting that direct interaction of MMR proteins with secondary structures formed by trinucleotide repeats in vivo, triggers replication fork pauses. We also show by chromatin immunoprecipitation that Msh2p is enriched at trinucleotide repeat tracts, in both stable and unstable orientations, this enrichment being dependent on MSH3 and MSH6. Finally, we show that overexpressing MSH2 favors the formation of heteroduplex regions, leading to an increase in contractions and expansions of CAG/CTG repeat tracts during replication, these heteroduplexes being dependent on both MSH3 and MSH6. These heteroduplex regions were not detected when a mutant msh2-E768A gene in which the ATPase domain was mutated was overexpressed. Our results unravel two new roles for mismatch-repair proteins: stabilization of heteroduplex regions and transient blocking of replication forks passing through such repeats. Both roles may involve direct interactions between MMR proteins and secondary structures formed by trinucleotide repeat tracts, although indirect interactions may not be formally excluded.

  19. Stall, Spiculate, or Run Away: The Fate of Fibers Growing towards Fluctuating Membranes

    Science.gov (United States)

    Daniels, D. R.; Marenduzzo, D.; Turner, M. S.

    2006-09-01

    We study the dynamics of a growing semiflexible fiber approaching a membrane at an angle. At late times we find three regimes: fiber stalling, when growth stops, runaway, in which the fiber bends away from the membrane, and another regime in which spicules form. We discuss which regions of the resulting “phase diagram” are explored by (i) single and bundled actin fibers in living cells, (ii) sickle hemoglobin fibers, and (iii) microtubules inside vesicles. We complement our analysis with 3D stochastic simulations.

  20. Prediction of H.A.W.T. blade stall and performance

    Energy Technology Data Exchange (ETDEWEB)

    Giannakidis, G.; Graham, J.M.R. [Imperial College, Dept. of Aeronautics, London (United Kingdom)

    1996-09-01

    A model is being developed for the prediction of Horizontal Axis Wind Turbine blade stall and performance coupled with a simple aeroelastic analysis model. For the aerodynamic calculation a two dimensional unsteady Navier-Stokes solver on a sectional basis on the blade is coupled with a three dimensional vortex lattice wake. Pressure coefficient distributions are calculated from the two dimensional viscous flow in each blade section. The aerodynamic computations are coupled with a vibrating beam model in order to incorporate flapwise deformations of the blade. (au) 17 refs.

  1. Modeling dynamic stall on wind turbine blades under rotationally augmented flow fields

    DEFF Research Database (Denmark)

    Guntur, Srinivas; Sørensen, Niels N.; Schreck, Scott

    2016-01-01

    Experiment Phase VI experimental data, including constant as well as continuously pitching blade conditions during axial operation; (2) data from unsteady delayed detached eddy simulations (DDES) carried out using the Technical University of Denmark’s in-house flow solver Ellipsys3D; and (3) data from...... agreement between the model and the experimental data in many cases, which suggests that the current two-dimensional dynamic stall model as used in blade element momentum-based aeroelastic codes may provide a reasonably accurate representation of three-dimensional rotor aerodynamics when used in combination...

  2. Standing Concertation Commmittee

    CERN Document Server

    HR Department

    2007-01-01

    Ordinary meeting on 2 november 2007 Extraordinary meeting on 12 November 2007 The main items discussed at the meetings of the Standing Concertation Committee on 2 November 2007 and 12 November included: Restaurants Supervisory Committee Report The committee took note of the report by the chairman of the Restaurants Supervisory Committee (RSC), T. Lagrange. In particular, it was recorded that, in Restaurant No. 1, the new kitchen and free flow arrangements had been inaugurated and all works had been commissioned on schedule in October 2007.The contractor, Novae, had taken over maintenance of the new kitchen. Some price increases were to be expected in the coming months due mainly to strong increases in the cost of basic ingredients. A problem with bad smells in the area of Restaurant No. 1 was being taken care of by tuning the ventilation system. The RSC wished to thank the management and staff of Restaurant No. 2 for their cooperation while Restaurant No 1 was ...

  3. Standing Concertation Committee

    CERN Document Server

    HR Department

    2009-01-01

    The main items discussed at the meetings of the Standing Concertation Committee in the first quarter of 2009 included: Merit Appraisal and Recognition Scheme (MARS) 2009 exercise The committee took note of 2009 MARS ceiling guidelines giving the advancement budget by career path and amounting to approx 1.80% of the basic salary bill. To this will be added 250 steps CERN-wide, financed by savings from implementation of the international indemnity for 2007, 2008 and the first half of 2009. The specific Senior Staff Guidelines, including the proposed number of promotions from Career Path E to F, were also noted. The guidelines with respect to step distribution were also noted: the minima and maxima remain the same as in previous years. Compliance with the guidelines will continue to be monitored closely (more details, including a frequently asked questions section). It was also noted that Financial Awards (awards for extraordinary service and responsibility allowances) may b...

  4. Standing Concertation Committee

    CERN Multimedia

    HR Department

    2009-01-01

    Ordinary Meeting on 11 May 2009 The meeting of the Standing Concertation Committee held on 11 May 2009 was entirely dedicated to the preparation of the TREF meeting on 19 & 20 May 2009. The Committee took note, discussed and agreed on some clarifications on a number of documents and presentations that the Management planned to submit and/or present to TREF on the following subjects: • Personnel statistics 2008: J. Purvis presented the Personnel Statistics for 2008 prepared by HR Department. In line with the previous year, key messages were firstly, a general reduction in staff (2544 to 2400, - 6%), secondly, a reduction in administrative services personnel (from 422 to 387, - 8%) and thirdly, a marked increase in the number of Users and Unpaid Associates (from 8369 to 9140, + 9%) • Five-Yearly Review 2010: A series of draft documents were submitted for discussion, comprising an introductory document explaining the statutory basis for the following four document...

  5. Standing Concertation Committee

    CERN Multimedia

    HR Department

    2010-01-01

    Main issues examined at the meeting of 2 October 2009 The October 2009 meeting of the Standing Concertation Committee was entirely devoted to preparation of TREF’s meeting on 21-22 October. The Committee took note of, discussed and agreed on clarifications needed to some of the documents and presentations that the Management intended to submit and/or present to TREF on the following subjects: Equal opportunities The Committee took note of a preliminary report on equal opportunities at CERN drawn up by D. Chromek-Burckhart, the Equal Opportunities Officer, and T. Smith, Chairman of the Equal Opportunities Advisory Panel, containing in particular a proposal for a new process for resolving harassment conflicts. Technical analysis of the CERN Health Insurance Scheme - Actuary’s Report The Committee took note of a presentation by P. Charpentier, Chairman of the CERN Health Insurance Supervisory Board (CHIS Board), on the 2009 actuarial report on the CERN Health Insurance Scheme (CHIS). Th...

  6. STANDING CONCERTATION COMMMITTEE

    CERN Multimedia

    HR Department

    2008-01-01

    ORDINARY MEETING ON 27 FEBRUARY 2008 The main items discussed at the meetings of the Standing Concertation Committee on 27 February 2008 included: Short-term Saved Leave Scheme The committee noted that, by the end of February 2008, some 600 staff had subscribed to the short-term saved leave scheme: approx 58% had subscribed 1 slice, 14% two slices, 5% three slices and 23% four slices. Administrative Circular No. 4 (Rev. 4) - Unemployment Insurance Scheme The committee agreed to recommend Administrative Circular No. 4 (Rev. 4) - Unemployment Insurance Scheme to the Director-General for approval. Administrative Circular No. 30 (Rev. 2) - Financial benefits upon taking up appointment and termination of contract The committee agreed to recommend Administrative Circular No. 30 (Rev. 2) - Financial Benefits upon taking up appointment and termination of contract to the Director-General for approval. Progressive Retirement Programme The Progressive Retirement Programme (PRP) was extended for a further year to 3...

  7. Standing Concertation Committee

    CERN Multimedia

    HR Department

    2008-01-01

    ORDINARY MEETING ON 27 FEBRUARY 2008 The main items discussed at the meetings of the Standing Concertation Committee on 27 February 2008 included: Short-term Saved Leave Scheme The Committee noted that, by the end of February 2008, some 600 staff had enrolled in the short-term saved leave scheme: approx. 58% had signed up for 1 slice, 14% for two slices, 5% for three slices and 23% for four slices. Administrative Circular No. 4 (Rev. 4) - Unemployment Insurance Scheme The Committee agreed to recommend the Director-General to approve Administrative Circular No. 4 (Rev. 4) - Unemployment Insurance Scheme. Administrative Circular No. 30 (Rev. 2) - Financial benefits upon taking up appointment and termination of contract The Committee agreed to recommend the Director-General to approve Administrative Circular No. 30 (Rev. 2) - Financial Benefits upon taking up appointment and termination of contract. Progressive Retirement Programme The Progressive Retirement Programme (PR...

  8. Food Irradiation. Standing legislation

    International Nuclear Information System (INIS)

    Verdejo S, M.

    1997-01-01

    The standing legislation in Mexico on food irradiation matter has its basis on the Constitutional Policy of the Mexican United States on the 4 Th. article by its refers to Secretary of Health, 27 Th. article to the Secretary of Energy and 123 Th. of the Secretary of Work and Social Security. The laws and regulations emanated of the proper Constitution establishing the general features which gives the normative frame to this activity. The general regulations of Radiological Safety expedited by the National Commission for Nuclear Safety and Safeguards to state the specifications which must be fulfill the industrial installations which utilizing ionizing radiations, between this line is founded, just as the requirements for the responsible of the radiological protection and the operation of these establishments. The project of Regulation of the General Health Law in matter of Sanitary Control of Benefits and Services, that in short time will be officialized, include a specific chapter on food irradiation which considers the International Organizations Recommendations and the pertaining harmonization stated for Latin America, which elaboration was in charge of specialized group where Mexico was participant. Additionally, the Secretary of Health has a Mexican Official Standard NOM-033-SSA1-1993 named 'Food irradiation; permissible doses in foods, raw materials and support additives' standing from the year 1995, where is established the associated requirements to the control registers, service constancies and dose limits for different groups of foods, moreover of the specific guidelines for its process. This standard will be adequate considering the updating Regulation of Benefits and Services and the limits established the Regulation for Latin America. The associated laws that cover in general terms it would be the requirements for food irradiation although such term is not manageable. (Author)

  9. Modelling of multiple short-length-scale stall cells in an axial compressor using evolved GMDH neural networks

    International Nuclear Information System (INIS)

    Amanifard, N.; Nariman-Zadeh, N.; Farahani, M.H.; Khalkhali, A.

    2008-01-01

    Over the past 15 years there have been several research efforts to capture the stall inception nature in axial flow compressors. However previous analytical models could not explain the formation of short-length-scale stall cells. This paper provides a new model based on evolved GMDH neural network for transient evolution of multiple short-length-scale stall cells in an axial compressor. Genetic Algorithms (GAs) are also employed for optimal design of connectivity configuration of such GMDH-type neural networks. In this way, low-pass filter (LPF) pressure trace near the rotor leading edge is modelled with respect to the variation of pressure coefficient, flow rate coefficient, and number of rotor rotations which are defined as inputs

  10. 14-3-3 Proteins regulate exonuclease 1-dependent processing of stalled replication forks.

    Directory of Open Access Journals (Sweden)

    Kim Engels

    2011-04-01

    Full Text Available Replication fork integrity, which is essential for the maintenance of genome stability, is monitored by checkpoint-mediated phosphorylation events. 14-3-3 proteins are able to bind phosphorylated proteins and were shown to play an undefined role under DNA replication stress. Exonuclease 1 (Exo1 processes stalled replication forks in checkpoint-defective yeast cells. We now identify 14-3-3 proteins as in vivo interaction partners of Exo1, both in yeast and mammalian cells. Yeast 14-3-3-deficient cells fail to induce Mec1-dependent Exo1 hyperphosphorylation and accumulate Exo1-dependent ssDNA gaps at stalled forks, as revealed by electron microscopy. This leads to persistent checkpoint activation and exacerbated recovery defects. Moreover, using DNA bi-dimensional electrophoresis, we show that 14-3-3 proteins promote fork progression under limiting nucleotide concentrations. We propose that 14-3-3 proteins assist in controlling the phosphorylation status of Exo1 and additional unknown targets, promoting fork progression, stability, and restart in response to DNA replication stress.

  11. Wind-up of a spanwise vortex in deepening transition and stall

    Energy Technology Data Exchange (ETDEWEB)

    Smith, F.T.; Bowles, R.I. [University Coll., London (United Kingdom). Dept. of Mathematics; Walker, J.D.A. [Mechanical Engineering Department, Packard Laboratory No. 19, Lehigh University, Bethlehem, PA 18015 (United States)

    2000-09-01

    A fundamental flow problem of unsteady wind-up of a spanwise vortex is studied in this theoretical work on deepening dynamic stall and transition in a boundary layer, internal layer or related unsteady motion. It examines the nonlinear evolution of the spanwise vortex produced when the local wall pressure develops a maximum or minimum, subsequent to the finite-time break-up of an interacting layer and the impact of normal pressure gradients. The evolution is controlled by an inner-outer interaction between the effects of the normal pressure gradient and the momentum jumps across and outside the vortex, which is situated near the strong inflexion point induced in the mean flow. Although the work concentrates on a particular internal-flow context, many of the flow properties found are generic and in particular apply for a more general case including external flows. Analysis and associated computations point to two main distinct trends in the vortex response, depending to a large extent on a parameter gauging the relative strengths of the above effects. The response is either an explosive one, provoking enhanced wind-up, growth and pressure in the vortex, or it is implosive, causing the vortex to shrink and virtually empty itself through unwinding, leaving little local pressure variation. A further discussion includes the after-effects of this vortex response and some of the connections with experiments and direct computations on deepening stall and transition. (orig.)

  12. Experimental Methods Applied in a Study of Stall Flutter in an Axial Flow Fan

    Directory of Open Access Journals (Sweden)

    John D. Gill

    2004-01-01

    Full Text Available Flutter testing is an integral part of aircraft gas turbine engine development. In typical flutter testing blade mounted sensors in the form of strain gages and casing mounted sensors in the form of light probes (NSMS are used. Casing mounted sensors have the advantage of being non-intrusive and can detect the vibratory response of each rotating blade. Other types of casing mounted sensors can also be used to detect flutter of rotating blades. In this investigation casing mounted high frequency response pressure transducers are used to characterize the part-speed stall flutter response of a single stage unshrouded axial-flow fan. These dynamic pressure transducers are evenly spaced around the circumference at a constant axial location upstream of the fan blade leading edge plane. The pre-recorded experimental data at 70% corrected speed is analyzed for the case where the fan is back-pressured into the stall flutter zone. The experimental data is analyzed using two probe and multi-probe techniques. The analysis techniques for each method are presented. Results from these two analysis methods indicate that flutter occurred at a frequency of 411 Hz with a dominant nodal diameter of 2. The multi-probe analysis technique is a valuable method that can be used to investigate the initiation of flutter in turbomachines.

  13. Active flow control of the laminar separation bubble on a plunging airfoil near stall

    Science.gov (United States)

    Pande, Arth; Agate, Mark; Little, Jesse; Fasel, Hermann

    2017-11-01

    The effects of small amplitude (A/c = 0.048) high frequency (πfc/U∞ = 0.70) plunging motion on the X-56A airfoil are examined experimentally at Re = 200,000 for 12° angle of attack (CL,MAX = 12.25°) . The purpose of this research is to study the aerodynamic influence of structural motion when the wing is vibrating close to its eigenfrequency near static stall. Specific focus is placed on the laminar separation bubble (LSB) near the leading edge and its control via plasma actuation. In the baseline case, the leading edge bubble bursts during the oscillation cycle causing moment stall. A collaborative computational effort has shown that small amplitude forcing at a frequency that is most amplified by the primary instability of the LSB (FLSB+= 1, Fc+= 52) generates coherent spanwise vortices that entrain freestream momentum, thus reducing separation all while maintaining a laminar flow state. Results (PIV and surface pressure) indicate that a similar control mechanism is effective in the experiments. This is significant given the existence of freestream turbulence in the wind tunnel which has been shown to limit the efficacy of this active flow control technique in a model problem using Direct Numerical Simulation. The implications of these results are discussed.

  14. Ethnic Dimensions of Guatemala's Stalled Transition: A Parity-Specific Analysis of Ladino and Indigenous Fertility Regimes.

    Science.gov (United States)

    Grace, Kathryn; Sweeney, Stuart

    2016-02-01

    In some contemporary populations, fertility levels appear to plateau, with women maintaining a consistently high level of fertility for a relatively extended period. Because this plateau does not reflect the historical patterns observed in Europe, the focus of most studies on fertility patterns, mechanisms underlying the plateau and the reinstatement of a decline have not been fully explored and are not fully understood. Through the construction of fertility histories of 25,000 women using multiple years of health survey data, we analyze some of the components of stalled fertility as they pertain to Guatemala, the only Central American country to have experienced a stalled fertility decline.

  15. Behaviorism

    Science.gov (United States)

    Moore, J.

    2011-01-01

    Early forms of psychology assumed that mental life was the appropriate subject matter for psychology, and introspection was an appropriate method to engage that subject matter. In 1913, John B. Watson proposed an alternative: classical S-R behaviorism. According to Watson, behavior was a subject matter in its own right, to be studied by the…

  16. Behavior

    NARCIS (Netherlands)

    Bouwman, L.I.

    2014-01-01

    Health behaviors are people’s actions, some purposefully deployed to promote or protect health; some thoughtlessly undertaken without concern for their potential risk to health; some consciously, even defiantly, deployed regardless of consequences to health. Risk behaviors are specific forms of

  17. Standing Concertation Commmittee

    CERN Multimedia

    HR Department

    2007-01-01

    Ordinary meeting on 27 February 2007 The main items discussed at the meeting of the Standing Concertation Committee on 27 February 2007 included: Saved Leave Scheme (SLS): It was announced that a Management/Staff Association working group had been set up to discuss the Saved Leave Scheme (SLS): Members: M. Büttner, E. Chiaveri (chair), Ph. Defert, D. Klem, M. Vitasse, J.-M. Saint-Viteux. It was noted that the Staff Association was launching a questionnaire on SLS and distributed to all members of the personnel. Merit Recognition Guidelines : in the context of the new Merit Appraisal and Recognition Scheme (MARS), the committee took note of the CERN-wide 2007 Merit Recognition Guidelines, including the Frequently Asked Questions on HR Department's dedicated website. Information on CERN's medium and long-term plans (MTP-LTP)/Contract renewals/ External mobility The Committee took note of the information provided on CERN's MTP-LTP and of documentation distributed at the meeting by the Staff Associatio...

  18. Standing concertation commmittee

    CERN Multimedia

    HR Department

    2009-01-01

    MEETINGS ON 2 AND 9 DECEMBER 2008 The main items discussed at the meetings of the Standing Concertation Committee on 2 and 9 December 2008 included: Medical Service Report 2007 The Committee took note of the report by Dr. E. Reymond (see http://sc-me.web.cern.ch/sc-me/fr/indexFR.htm) and of a number of points raised during the discussion. It was noted that the number of professional accidents declined in 2007 (361 accidents) in comparison with 2006 (483), as well as their gravity and frequency. The CERN Medical Service carried out a study on cancer prevalence (number of cases) and incidence (new cases per year per 100000 people), between 1993 and 2007, which identified some prostate, breast and colorectal cancers, though less than in the two Host States. Specific preventive actions will be promoted by the CERN CHISboard and the Medical Service in this context as well as in other areas. The committee expressed its thanks to all members of the Medical Service for their work i...

  19. Standing Concertation Committee

    CERN Multimedia

    2007-01-01

    ORDINARY MEETING ON 30 JANUARY 2007 The main items discussed at the meeting of the Standing Concertation Committee on 30 January 2007 included: Administrative Circular No. 26: with the introduction of the merit recognition system in the framework of the 5-yearly review of CERN employment conditions, Administrative Circular No. 26 has been revised. The Committee took note of the revised document which is being finalized for submission to the Director-General for approval in the near future. Technical analysis of CERN Health Insurance Scheme: the Committee was informed that a group has been set up by the Director-General to analyse the financial situation of the CERN Health Insurance Scheme in the short and long term, and to propose measures to ensure that the Scheme remains in financial balance, with adequate cover, over the medium term. The group's terms of reference and membership were communicated. Voluntary programmes It was announced that the programmes: 'part-time work as a pre-retirement mea...

  20. Standing Concertation Committee

    CERN Multimedia

    2007-01-01

    Ordinary meeting on 30 January 2007 The main items discussed at the meeting of the Standing Concertation Committee on 30 January 2007 included: Administrative Circular No. 26: with the introduction of the merit recognition system in the framework of the 5-yearly review of CERN employment conditions, Administrative Circular No. 26 has been revised. The committee took note of the revised document which is being finalized for submission to the Director-General for approval in the near future. Technical analysis of CERN Health Insurance Scheme: the Committee was informed that a group has been set up by the Director-General to analyse the financial situation of the CERN Health Insurance Scheme in the short and long term, and to propose measures to ensure that the Scheme remains in financial balance, with adequate cover, over the medium term. The group's terms of reference and membership were communicated. Voluntary programmes It was announced that the programmes: 'part-time work as a pre-retirement measure...

  1. Stand-up physics

    CERN Multimedia

    2009-01-01

    A CMS physicist and amateur stand up comic was named the winner of NESTA FameLab 2009. Tom Whyntie battled it out with nine others young scientists from across the UK to win the contest to find the country’s next top science communicator. Tom Whyntie with his prize money after the NESTA Famelab final.Tom Whyntie, who is currently doing his PhD on the CMS experiment, managed to persuade his supervisor to give him a few days off on 5 June so he could fly back to the UK for the final of NESTA FameLab 2009. In the competition, which has been dubbed ‘the X Factor for scientists’, he had just three minutes to explain a complex scientific idea to a panel of judges made up of high-profile science professionals. During the final, he captivated the audience with his talk about how finding nothing at the LHC, far from being a waste of £5 billion, would actually catalyse the next scientific revolution. It Whyntie’s own words: "If the L...

  2. Standing Concertation Committee

    CERN Multimedia

    HR Department

    2007-01-01

    ORDINARY MEETING ON 27 FEBRUARY 2007 The main items discussed at the meeting of the Standing Concertation Committee on 27 February 2007 included: Saved Leave Scheme (SLS): It was announced that a Management/Staff Association working group had been set up to discuss the Saved Leave Scheme (SLS): Members : M. Büttner, E. Chiaveri (chair), Ph. Defert, D. Klem, M. Vitasse, J.-M. Saint-Viteux. It was noted that the Staff Association was launching a questionnaire on SLS and distributed to all members of the personnel. Merit Recognition Guidelines: In the context of the new Merit Appraisal and Recognition Scheme (MARS), the committee took note of the CERN-wide 2007 Merit Recognition Guidelines, including the Frequently Asked Questions on HR Department's dedicated website. Information on CERN's medium and long-term plans (MTP-LTP)/Contract renewals/ External mobility The Committee took note of the information provided on CERN's MTP-LTP and of documentation distributed at the meeting by the Staff ...

  3. Dynamics of Connecticut hemlock stands

    Science.gov (United States)

    Jeffrey S. Ward; David M. Smith

    2000-01-01

    The stand dynamics and production of two one-acre plots of eastern hemlock (Tsuga canadensis L) in Connecticut have been followed for more than six decades. Data were recorded for all individual trees. One plot (Saltonstall) was established in 1924 after the removal of a hardwood overstory. This stand had a nearly pure, almost fully closed understory...

  4. A-1 Test Stand work

    Science.gov (United States)

    2010-01-01

    Employees at NASA's John C. Stennis Space Center work to maneuver a structural steam beam into place on the A-1 Test Stand on Jan. 13. The beam was one of several needed to form the thrust takeout structure that will support a new thrust measurement system being installed on the stand for future rocket engine testing. Once lifted onto the stand, the beams had to be hoisted into place through the center of the test stand, with only two inches of clearance on each side. The new thrust measurement system represents a state-of-the-art upgrade from the equipment installed more than 40 years ago when the test stand was first constructed.

  5. Behavioral Sciences in a Changing Army. Proceedings in AMEDD Behavioral Sciences Seminar, 19 - 23 March 1979,

    Science.gov (United States)

    1979-03-23

    confronting us because we are vitally concerned with many of those issues. In order to help set the stage for that, I’d like to describe where I think Social...complaint concerning thle behavior of a member of (2) Reprmand ;!?is .4sinciatiof stall be inl vt -t. iflJ signo ~d bl, MeO com- 3)Ssesinfo emesi

  6. Associations between lying behavior and lameness in Canadian Holstein-Friesian cows housed in freestall barns.

    Science.gov (United States)

    Solano, L; Barkema, H W; Pajor, E A; Mason, S; LeBlanc, S J; Nash, C G R; Haley, D B; Pellerin, D; Rushen, J; de Passillé, A M; Vasseur, E; Orsel, K

    2016-03-01

    /bout, or standard deviations of bout duration over 4 d ≥ 70 min had 3.7, 1.7, 2.5, and 3.0 higher odds of being lame, respectively. Factors related to comfort of lying and standing surfaces significantly affected lying behavior. Finally, we inferred that automated measures of lying behavior could contribute to lameness detection, especially when interpreted in the context of other factors known to affect lying behavior, including those associated with the individual cow (e.g., parity and stage of lactation) or environment (e.g., stall surface). Copyright © 2016 American Dairy Science Association. Published by Elsevier Inc. All rights reserved.

  7. Spins, Stalls, and Shutdowns: Pitfalls of Qualitative Policing and Security Research

    Directory of Open Access Journals (Sweden)

    Randy K. Lippert

    2015-11-01

    Full Text Available This article explores key elements of qualitative research on policing and security agencies, including barriers encountered and strategies to prevent them. While it is oft-assumed that policing/security agencies are difficult to access due to their clandestine or bureaucratic nature, this article demonstrates this is not necessarily the case, as access was gained for three distinct qualitative research projects. Yet, access and subsequent research were not without pitfalls, which we term security spins, security stalls, and security shutdowns. We illustrate how each was encountered and argue these pitfalls are akin to researchers falling into risk categories, not unlike those used by policing/security agents in their work. Before concluding we discuss methodological strategies for scholars to avoid these pitfalls and to advance research that critically interrogates the immense policing/security realm. URN: http://nbn-resolving.de/urn:nbn:de:0114-fqs1601108

  8. URANS simulations of separated flow with stall cells over an NREL S826 airfoil

    Science.gov (United States)

    Sarlak, H.; Nishino, T.; Sørensen, J. N.

    2016-06-01

    A series of wind tunnel measurements and oil flow visualization was recently carried out at the Technical University of Denmark in order to investigate flow characteristics over a 14% thick NREL S826 airfoil at low Reynolds numbers. This paper aims at presenting numerical simulations of the same airfoil using unsteady Reynolds-averaged Navier-Stokes (URANS) approach. Results of the simulations are demonstrated in terms of mean flow velocity, lift and drag, as well as pressure distribution, and validated against available experimental data. The simulations are carried out with a wide computational domain (with a span-to-chord ratio of 5) and it is illustrated that the URANS approach is capable of predicting 3D spanwise structures, known as stall cells.

  9. Fixed-speed active-stall wind turbines in offshore applications

    DEFF Research Database (Denmark)

    Akhmatov, Vladislav; Nielsen, Arne Hejde

    2005-01-01

    A large offshore wind farm in the East Danish power system was commissioned in 2003 at Rodsand. The power capacity of the wind farm is 165 MW divided between 72 wind turbines. For this large offshore application, robust and well-known wind technology has been chosen in the form of fixed-speed, ac......, active-stall wind turbines equipped with induction generators. In this paper, maintaining and improving the short-term voltage stability is discussed and systematized in terms of this wind technology. Copyright (C) 2004 John Wiley Sons, Ltd.......A large offshore wind farm in the East Danish power system was commissioned in 2003 at Rodsand. The power capacity of the wind farm is 165 MW divided between 72 wind turbines. For this large offshore application, robust and well-known wind technology has been chosen in the form of fixed-speed...

  10. Performance augmentation with vortex generators: Design and testing for stall-regulated AWT-26 turbine

    Energy Technology Data Exchange (ETDEWEB)

    Griffin, D.A. [Advanced Wind Turbines Inc., Seattle, WA (United States)

    1996-12-31

    A study investigated the use of vortex generators (VGs) for performance augmentation of the stall-regulated AWT-26 wind turbine. Based on wind-tunnel results and analysis, a VG array was designed for and tested on the AWT-26 prototype, designated Pt. Performance and loads data were measured for P1, both with and without VGs installed. The turbine performance with VGs met most of the design requirements; power output was increased at moderate wind speeds with a minimal effect on peak power. However, VG drag penalties caused a loss in power output for low wind speeds, such that performance with VGs resulted in a net decrease in AEP for wind speed sites up to 8.5 m/s. 8 refs., 8 figs., 3 tabs.

  11. Listeria phospholipases subvert host autophagic defenses by stalling pre-autophagosomal structures

    Science.gov (United States)

    Tattoli, Ivan; Sorbara, Matthew T; Yang, Chloe; Tooze, Sharon A; Philpott, Dana J; Girardin, Stephen E

    2013-01-01

    Listeria can escape host autophagy defense pathways through mechanisms that remain poorly understood. We show here that in epithelial cells, Listeriolysin (LLO)-dependent cytosolic escape of Listeria triggered a transient amino-acid starvation host response characterized by GCN2 phosphorylation, ATF3 induction and mTOR inhibition, the latter favouring a pro-autophagic cellular environment. Surprisingly, rapid recovery of mTOR signalling was neither sufficient nor necessary for Listeria avoidance of autophagic targeting. Instead, we observed that Listeria phospholipases PlcA and PlcB reduced autophagic flux and phosphatidylinositol 3-phosphate (PI3P) levels, causing pre-autophagosomal structure stalling and preventing efficient targeting of cytosolic bacteria. In co-infection experiments, wild-type Listeria protected PlcA/B-deficient bacteria from autophagy-mediated clearance. Thus, our results uncover a critical role for Listeria phospholipases C in the inhibition of autophagic flux, favouring bacterial escape from host autophagic defense. PMID:24162724

  12. Benchmarking welfare indicators in 73 free-stall dairy farms in north-western Spain

    Science.gov (United States)

    Trillo, Yolanda; Quintela, Luis Angel; Barrio, Mónica; Becerra, Juan José; Peña, Ana Isabel; Vigo, Marcos; Garcia Herradon, Pedro

    2017-01-01

    The aim of this study was to describe the status of body condition score (BCS), hock injuries prevalence, locomotion and body hygiene score as animal welfare measures in 73 free-stall dairy cattle farms in Lugo (Spain). A benchmarking process was established across farms: (1) the animal-based indicators were ordered from low to high values; (2) The farms were classified into three categories based on the number of indicators within less than the 25th percentile, 25th to 75th percentile and above the 75th percentile. The median prevalence of unsuitable BCS, hock injuries and clinical lameness was (median (range)) 51.7 per cent (13.3 to 89.5 per cent), 40.0 per cent (7.0per cent to 100 per cent) and 9.0 per cent (0per cent to 60.0 per cent) respectively. The dirtiness of the cow’s coat had a high prevalence (73.0 per cent (37.5per cent to 100 per cent)). Most farms did not display consistently good or poor animal-based indicators and each farm had its own set of strong and weak points. Moreover, facilities design and management practices were described to understand source of the observations made of the cows. The incidence of overstocking was 31.5 per cent for stalls and 26.0 per cent for headlocks. The front lunge space was reduced (farms and they could benefit from others by changing management practices related to facilities and herds. PMID:29018530

  13. Reducing Respiratory Health Risks to Horses and Workers: A Comparison of Two Stall Bedding Materials

    Directory of Open Access Journals (Sweden)

    Markku Saastamoinen

    2015-10-01

    Full Text Available Stable air quality and the choice of bedding material are an important health issue both in horses and people working or visiting horse stables. Risks of impaired respiratory health are those that can especially be avoided by improving air quality in the stable. The choice of bedding material is particularly important in cold climate conditions; where horses are kept most of the day and year indoors throughout their life. This study examined the effect of two bedding materials; wood shavings and peat; on stable air quality and health of horses. Ammonia and dust levels were also measured to assess conditions in the stable. Ammonia was not detected or was at very low levels (<0.25 ppm in the boxes in which peat was used as bedding; but its concentration was clearly higher (1.5–7.0 ppm in stalls with wood shavings as bedding. Personal measurements of workers revealed quite high ammonia exposure (5.9 ppm8h in the boxes in which wood shavings were used; but no exposure was Animals 2015, 5 966 observed in stalls bedded with peat. The respiratory symptoms in horses increased regardless of the bedding material at the beginning of the study. The health status of the horses in the peat bedding group returned to the initial level in the end of the trial but horses bedded with wood shavings continued to be symptomatic. The hooves of the horses with peat bedding had a better moisture content than those of the horses bedded with wood shavings. The results suggest that peat is a better bedding material for horses than wood shavings regarding the health of both horses and stable workers.

  14. Climate trends account for stalled wheat yields in Australia since 1990.

    Science.gov (United States)

    Hochman, Zvi; Gobbett, David L; Horan, Heidi

    2017-05-01

    Global food security requires that grain yields continue to increase to 2050, yet yields have stalled in many developed countries. This disturbing trend has so far been only partially explained. Here, we show that wheat yields in Australia have stalled since 1990 and investigate the extent to which climate trends account for this observation. Based on simulation of 50 sites with quality weather data, that are representative of the agro-ecological zones and of soil types in the grain zone, we show that water-limited yield potential declined by 27% over a 26 year period from 1990 to 2015. We attribute this decline to reduced rainfall and to rising temperatures while the positive effect of elevated atmospheric CO 2 concentrations prevented a further 4% loss relative to 1990 yields. Closer investigation of three sites revealed the nature of the simulated response of water-limited yield to water availability, water stress and maximum temperatures. At all three sites, maximum temperature hastened time from sowing to flowering and to maturity and reduced grain number per m 2 and average weight per grain. This 27% climate-driven decline in water-limited yield is not fully expressed in actual national yields. This is due to an unprecedented rate of technology-driven gains closing the gap between actual and water-limited potential yields by 25 kg ha -1  yr -1 enabling relative yields to increase from 39% in 1990 to 55% in 2015. It remains to be seen whether technology can continue to maintain current yields, let alone increase them to those required by 2050. © 2017 John Wiley & Sons Ltd.

  15. Low-Order Modeling of Dynamic Stall on Airfoils in Incompressible Flow

    Science.gov (United States)

    Narsipur, Shreyas

    Unsteady aerodynamics has been a topic of research since the late 1930's and has increased in popularity among researchers studying dynamic stall in helicopters, insect/bird flight, micro air vehicles, wind-turbine aerodynamics, and ow-energy harvesting devices. Several experimental and computational studies have helped researchers gain a good understanding of the unsteady ow phenomena, but have proved to be expensive and time-intensive for rapid design and analysis purposes. Since the early 1970's, the push to develop low-order models to solve unsteady ow problems has resulted in several semi-empirical models capable of effectively analyzing unsteady aerodynamics in a fraction of the time required by high-order methods. However, due to the various complexities associated with time-dependent flows, several empirical constants and curve fits derived from existing experimental and computational results are required by the semi-empirical models to be an effective analysis tool. The aim of the current work is to develop a low-order model capable of simulating incompressible dynamic-stall type ow problems with a focus on accurately modeling the unsteady ow physics with the aim of reducing empirical dependencies. The lumped-vortex-element (LVE) algorithm is used as the baseline unsteady inviscid model to which augmentations are applied to model unsteady viscous effects. The current research is divided into two phases. The first phase focused on augmentations aimed at modeling pure unsteady trailing-edge boundary-layer separation and stall without leading-edge vortex (LEV) formation. The second phase is targeted at including LEV shedding capabilities to the LVE algorithm and combining with the trailing-edge separation model from phase one to realize a holistic, optimized, and robust low-order dynamic stall model. In phase one, initial augmentations to theory were focused on modeling the effects of steady trailing-edge separation by implementing a non-linear decambering

  16. Droplets bouncing on a standing wave field

    Science.gov (United States)

    Pucci, Giuseppe; Tambasco, Lucas; Harris, Daniel; Bush, John

    2017-11-01

    A liquid bath subject to a vertical vibration becomes unstable to standing surface waves at a critical vibrational acceleration known as the Faraday threshold. We examine the behavior of a millimetric droplet bouncing on the surface of a quasi-one-dimensional fluid channel above the Faraday threshold. We identify a sequence of bifurcations that occurs as the vibrational acceleration is increased progressively, ultimately leading to the erratic, diffusive motion of the droplet along the length of the channel. A simple theoretical model is presented. This work was supported by the US National Science Foundation through Grants CMMI-1333242 and DMS-1614043.

  17. Associations of dairy cow behavior, barn hygiene, cow hygiene, and risk of elevated somatic cell count.

    Science.gov (United States)

    Devries, T J; Aarnoudse, M G; Barkema, H W; Leslie, K E; von Keyserlingk, M A G

    2012-10-01

    Poor dairy cow hygiene has been consistently associated with elevated somatic cell count (SCC) and the risk of subclinical mastitis. The objective of this study was to determine the associations between dairy cow standing and lying behavior, barn hygiene, cow hygiene, and the risk of experiencing elevated SCC. Lactating Holstein dairy cows (n=69; 86 ± 51 DIM; parity: 2.0 ± 1.2; means ± SD), kept in 1 of 2 groups, were monitored over a 4-mo period. Each group contained 61 ± 1 (mean ± SD) cows over the study period; complete data were obtained from 37 and 32 animals within each respective group. Cows were housed in a sand-bedded, freestall barn with 2 symmetrical pens, each with a free cow traffic automatic milking system. To vary barn hygiene, in 4 consecutive 28-d periods, alley manure scrapers in each of the 2 pens were randomly assigned to frequencies of operation of 3, 6, 12, and 24 times per day. During the last 7 d of each period, cow hygiene (upper leg/flank, lower legs, and udder; scale of 1 = very clean to 4 = very dirty) and stall hygiene (number of 0.15×0.15-m squares contaminated with manure in a 1.20×1.65-m grid) were recorded. Standing and lying behavior of the cows were collected during those days using data loggers. Individual-cow SCC was recorded at the beginning and end of each 28-d period. Elevated SCC was used as an indicator of subclinical mastitis; incidence of elevated SCC was defined as having a SCC >200,000 cells/mL at the end of each 28-d period, when SCC was cows having poorer hygiene. Poor udder hygiene was associated with poor stall hygiene. Longer lying duration was associated with poor hygiene of the upper legs/flank and udder. Greater premilking standing duration was associated with poor udder hygiene and decreased frequency of lying bouts was associated with poor hygiene of the lower legs. Higher milk yield was associated with poor hygiene of the udder and lower legs; multiparous cows had poorer hygiene of the upper legs

  18. Finite Element Analysis of a Free-Standing Staircase | Ajagbe ...

    African Journals Online (AJOL)

    The existing approximate analytical methods of analyzing free-standing stairs fail to predict the distribution of any stress resultant and the actual three dimensional behavior of the stair slab system. A more rationale but simple and accurate method of analysis based on finite element method is presented. Plate flexural ...

  19. Design of a 21 m blade with Risø-A1 airfoils for active stall controlled wind turbines

    DEFF Research Database (Denmark)

    Fuglsang, Peter; Sangill, O.; Hansen, P.

    2002-01-01

    This is the final report, from the project, "Design of a Rotor/Airfoil Family for Active Stall-regulated Wind Turbines by Use of Multi-point Optimization". It describes the full scale testing of a 21 m wind turbine blade specially designed for active stallregulation. Design objectives were...... increased ratio of produced energy to turbine loads and more stable power control characteristics. Both were taken directly into account during the design of the blade using numerical optimization. The blade used theRisø-A1 airfoil family, which was specially designed for operation on wind turbine blades...... be concluded that the new LM 21.0 ASR blade could replace the LM 21.0P leading to improved cost efficiency and that the Risø-A1 airfoils were well suited for active stall control. With the newestablished knowledge of the actual airfoil characteristics, a possible future blade design could be made also...

  20. Experimental investigation of flow-induced vibration of a pitch-plunge NACA 0015 airfoil under deep dynamic stall

    Czech Academy of Sciences Publication Activity Database

    Šidlof, Petr; Vlček, Václav; Štěpán, M.

    2016-01-01

    Roč. 67, November (2016), s. 48-59 ISSN 0889-9746 R&D Projects: GA ČR GA13-10527S Institutional support: RVO:61388998 Keywords : NACA 0015 airfoil * aeroelasticity * stall flutter * dynamic stall * limit cycle oscillation * schlieren Subject RIV: BI - Acoustics Impact factor: 2.021, year: 2016 http://ac.els-cdn.com/S0889974615300724/1-s2.0-S0889974615300724-main.pdf?_tid=31f9fa5a-d1c0-11e6-a705-00000aab0f26&acdnat=1483453588_64a6e8b2119c9afad3639cdec32a4569

  1. Static standing and dynamic walking of a practical biped robot

    Energy Technology Data Exchange (ETDEWEB)

    Zheng, Yuan F.; Rao, M.

    1987-01-01

    The study of static standing and dynamic walking of a practical biped robot is presented in this research report. A systematic method for describing the kinematic behavior of a biped robot is first developed. The development is based on the well-known Denavit-Hartenburg convention. As a result, the method is basically the same as the one used for robot manipulators, except for some considerations given to the unique functions and structure of a biped robot. The static standing of a biped robot is then studied. It is argued that static standing capability is very important if a biped robot is to be employed in an industrial environment. In order to measure the performance of the biped in static standing in terms of its stability, two parameters, stable margin and stable index, are introduced. Based on these parameters, optimal stability of the biped robot with one-foot and two-foot standing cases are discussed. For dynamic walking, a mathematical treatment is first described. Conclusion is reached that by proper positioning of the landing, stable dynamic walking can be realized. A practical biped robot is introduced in the final part of the report. Experimental results of static standing and dynamic walking of the biped robot are presented, to verify the theoretical results. 28 refs., 9 figs., 1 tab.

  2. Isotope separation by standing waves

    International Nuclear Information System (INIS)

    Altshuler, S.

    1984-01-01

    The separation of isotopes is accomplished by scattering a beam of particles from a standing electromagnetic wave. The particles may consist of either atoms or molecules, the beam having in either case a desired isotope and at least one other. The particle beam is directed so as to impinge on the standing electromagnetic wave, which may be a light wave. The particles, that is, the atomic or molecular quantum-mechanical waves, see basically a diffraction grating corresponding to the troughs and peaks of the electromagnetic wave. The frequency of the standing electromagnetic wave substantially corresponds to an internal energy level-transition of the desired isotope. Accordingly, the desired isotope is spatially separated by being scattered or diffracted. (author)

  3. Advance Ratio Effects on the Dynamic-stall Vortex of a Rotating Blade in Steady Forward Flight

    Science.gov (United States)

    2014-08-06

    of the wind tunnel and is illustrated in Fig. 1. In order to simplify the operations, a two-bladed rotor design was preferred. The setup had manually...to wind turbines, compressors, helicopter rotors , and even insect wing aerodynamics. Dynamic stall occurs on rotating blades of a helicopter in forward...between the flow structure on helicopter rotor blades, wind turbine blades, and insect wings. Due to these wide engineering implications there has

  4. Parametric analyses for synthetic jet control on separation and stall over rotor airfoil

    Directory of Open Access Journals (Sweden)

    Zhao Guoqing

    2014-10-01

    Full Text Available Numerical simulations are performed to investigate the effects of synthetic jet control on separation and stall over rotor airfoils. The preconditioned and unsteady Reynolds-averaged Navier–Stokes equations coupled with a k − ω shear stream transport turbulence model are employed to accomplish the flowfield simulation of rotor airfoils under jet control. Additionally, a velocity boundary condition modeled by a sinusoidal function is developed to fulfill the perturbation effect of periodic jets. The validity of the present CFD procedure is evaluated by the simulated results of an isolated synthetic jet and the jet control case for airfoil NACA0015. Then, parametric analyses are conducted specifically for an OA213 rotor airfoil to investigate the effects of jet parameters (forcing frequency, jet location and momentum coefficient, jet direction, and distribution of jet arrays on the control effect of the aerodynamic characteristics of a rotor airfoil. Preliminary results indicate that the efficiency of jet control can be improved with specific frequencies (the best lift-drag ratio at F+ = 2.0 and jet angles (40° or 75° when the jets are located near the separation point of the rotor airfoil. Furthermore, as a result of a suitable combination of jet arrays, the lift coefficient of the airfoil can be improved by nearly 100%, and the corresponding drag coefficient decreased by 26.5% in comparison with the single point control case.

  5. Analysis of the grid connection sequence of stall- and pitch-controlled wind turbines

    Energy Technology Data Exchange (ETDEWEB)

    Quinonez-Varela, G.; Cruden, A.; Anaya-Lara, O.; Tumilty, R.; McDonald, J.R. [Univ. of Strathclyde, Inst. for Energy and Environment (United Kingdom)

    2007-11-15

    The realistic modelling of wind turbines and wind farms is crucial in any form of power system analysis, and consequently, knowledge about their electrical characteristics and performance is also vital. One of the operating conditions producing major transient interaction between a wind turbine generator and the local grid is the grid connection sequence itself, which is particularly significant in fixed-speed turbines. This paper presents experimental measurements of the grid connection sequence of both types of fixed speed wind turbines, i.e. stall- and pitch-controlled via a soft-start device performed at two existing wind farms. Some of the results evidenced significant discrepancies between the actual soft-start operating intervals and those stated/suggested by open literature. The discussion of the paper focuses on highlighting the importance of accurate modelling of the grid connection sequence in order to avoid erroneous estimations of the interaction between the turbine and the grid during this operating state, or inappropriate design of the grid connection. (au)

  6. ETAA1 acts at stalled replication forks to maintain genome integrity

    Science.gov (United States)

    Bass, Thomas E.; Luzwick, Jessica W.; Kavanaugh, Gina; Carroll, Clinton; Dungrawala, Huzefa; Glick, Gloria G.; Feldkamp, Michael D.; Putney, Reid; Chazin, Walter J.; Cortez, David

    2017-01-01

    The ATR checkpoint kinase coordinates cellular responses to DNA replication stress. Budding yeast contain three activators of Mec1 (the ATR orthologue); however, only TOPBP1 is known to activate ATR in vertebrates. We identified ETAA1 as a replication stress response protein in two proteomic screens. ETAA1-deficient cells accumulate double-strand breaks, sister chromatid exchanges, and other hallmarks of genome instability. They are also hyper-sensitive to replication stress and have increased frequencies of replication fork collapse. ETAA1 contains two RPA-interaction motifs that localize ETAA1 to stalled replication forks. It also interacts with several DNA damage response proteins including the BLM/TOP3α/RMI1/RMI2 and ATR/ATRIP complexes. It binds ATR/ATRIP directly using a motif with sequence similarity to the TOPBP1-ATR activation domain; and like TOPBP1, ETAA1 acts as a direct ATR activator. ETAA1 functions in parallel to the TOPBP1/RAD9/HUS1/RAD1 pathway to regulate ATR and maintain genome stability. Thus, vertebrate cells contain at least two ATR activating proteins. PMID:27723720

  7. Why commercialization of gene therapy stalled; examining the life cycles of gene therapy technologies.

    Science.gov (United States)

    Ledley, F D; McNamee, L M; Uzdil, V; Morgan, I W

    2014-02-01

    This report examines the commercialization of gene therapy in the context of innovation theories that posit a relationship between the maturation of a technology through its life cycle and prospects for successful product development. We show that the field of gene therapy has matured steadily since the 1980s, with the congruent accumulation of >35 000 papers, >16 000 US patents, >1800 clinical trials and >$4.3 billion in capital investment in gene therapy companies. Gene therapy technologies comprise a series of dissimilar approaches for gene delivery, each of which has introduced a distinct product architecture. Using bibliometric methods, we quantify the maturation of each technology through a characteristic life cycle S-curve, from a Nascent stage, through a Growing stage of exponential advance, toward an Established stage and projected limit. Capital investment in gene therapy is shown to have occurred predominantly in Nascent stage technologies and to be negatively correlated with maturity. Gene therapy technologies are now achieving the level of maturity that innovation research and biotechnology experience suggest may be requisite for efficient product development. Asynchrony between the maturation of gene therapy technologies and capital investment in development-focused business models may have stalled the commercialization of gene therapy.

  8. Flow-around modes for a rhomboid wing with a stall vortex in the shock layer

    Science.gov (United States)

    Zubin, M. A.; Maximov, F. A.; Ostapenko, N. A.

    2017-12-01

    The results of theoretical and experimental investigation of an asymmetrical hypersonic flow around a V-shaped wing with the opening angle larger than π on the modes with attached shockwaves on forward edges, when the stall flow is implemented on the leeward wing cantilever behind the kink point of the cross contour. In this case, a vortex of nonviscous nature is formed in which the velocities on the sphere exceeding the speed of sound and resulting in the occurrence of pressure shocks with an intensity sufficient for the separation of the turbulent boundary layer take place in the reverse flow according to the calculations within the framework of the ideal gas. It is experimentally established that a separation boundary layer can exist in the reverse flow, and its structure is subject to the laws inherent to the reverse flow in the separation region of the turbulent boundary layer arising in the supersonic conic flow under the action of a shockwave incident to the boundary layer.

  9. Histone H2B mono-ubiquitylation maintains genomic integrity at stalled replication forks

    Science.gov (United States)

    Northam, Matthew R.; Trujillo, Kelly M.

    2016-01-01

    Histone modifications play an important role in regulating access to DNA for transcription, DNA repair and DNA replication. A central player in these events is the mono-ubiquitylation of histone H2B (H2Bub1), which has been shown to regulate nucleosome dynamics. Previously, it was shown that H2Bub1 was important for nucleosome assembly onto nascent DNA at active replication forks. In the absence of H2Bub1, incomplete chromatin structures resulted in several replication defects. Here, we report new evidence, which shows that loss of H2Bub1 contributes to genomic instability in yeast. Specifically, we demonstrate that H2Bub1-deficient yeast accumulate mutations at a high frequency under conditions of replicative stress. This phenotype is due to an aberrant DNA Damage Tolerance (DDT) response upon fork stalling. We show that H2Bub1 normally functions to promote error-free translesion synthesis (TLS) mediated by DNA polymerase eta (Polη). Without H2Bub1, DNA polymerase zeta (Polζ) is responsible for a highly mutagenic alternative mechanism. While H2Bub1 does not appear to regulate other DDT pathways, error-free DDT mechanisms are employed by H2Bub1-deficient cells as another means for survival. However, in these instances, the anti-recombinase, Srs2, is essential to prevent the accumulation of toxic HR intermediates that arise in an unconstrained chromatin environment. PMID:27458205

  10. Exploring farmers’ seasonal and full year adoption of stall feeding of livestock in Tigrai region, Ethiopia

    Directory of Open Access Journals (Sweden)

    Hadush Muuz

    2017-01-01

    Full Text Available Adoption of stall feeding (SF of livestock was assessed in northern Ethiopia based on a household survey conducted in 2015. The study covered 21 communities in Tigrai to account for differences in agroecology. The purpose of this study was to understand the driving factors of full or seasonal SF adoption and its intensity. A Heckman selection model was used to estimate adoption and extent of adoption based on a model of technology adoption within an agricultural household framework, and Poisson Model for explaining the number of SF adopting seasons. The descriptive results indicate that 36% of the farmers were actually practicing SF in a full year whereas 55.6% were seasonal adopters in the study area. Empirical results of this study showed that our result is in favor of the Boserupian hypothesis indicating that small grazing land and large exclosure are associated with a higher probability of use of SF and with a higher number of SF adopting seasons. In a similar vein, small average village farm size stimulated SF adoption and adopting seasons, Availability of labor and a number of breed cows significantly increased the probability of using SF by 0.01% and 66% respectively. While animal shock had a marginal effect of 14%, factors such as access to information and early exposure increased SF adoption by about 18% and 6%. Similarly, the positive marginal effect of real milk price is 15%. However, SF appears to be less attractive to those farmers with more herd size and less crop residue.

  11. Residual Liquefaction under Standing Waves

    DEFF Research Database (Denmark)

    Kirca, V.S. Ozgur; Sumer, B. Mutlu; Fredsøe, Jørgen

    2012-01-01

    This paper summarizes the results of an experimental study which deals with the residual liquefaction of seabed under standing waves. It is shown that the seabed liquefaction under standing waves, although qualitatively similar, exhibits features different from that caused by progressive waves....... The experimental results show that the buildup of pore-water pressure and the resulting liquefaction first starts at the nodal section and spreads towards the antinodal section. The number of waves to cause liquefaction at the nodal section appears to be equal to that experienced in progressive waves for the same...

  12. An Induction Linac Test Stand

    CERN Document Server

    De Hope, William; Kihara, Ron; Ong, Mike; Vogtlin, George; Zentler, Jan-Mark

    2005-01-01

    A single-cell test stand has been constructed to facilitate study and guide improvements of the induction electron linac at the FXR radiographic facility at LLNL.* This paper will discuss how modifications in pulse compression and shaping, pulse power transmission, initial ferrite state, and accelerator cell loading have been performed on the test stand and can be applied to the entire accelerator. Some of the specialized diagnostics being used will be described. Finally, the paper will discuss how computer modeling and judicious timing control can be used to optimize accelerator performance by making only selective changes that can be accomplished at minimal cost.

  13. Transonic Wind Tunnel Modernization for Experimental Investigation of Dynamic Stall in a Wide Range of Mach Numbers by Plasma Actuators with Combined Energy/Momentum Action

    Science.gov (United States)

    2015-01-02

    wind tunnel for the study of plasma based methods for the control of dynamic stall for helicopter rotor blades. The tunnel has a 3D positioning...SECURITY CLASSIFICATION OF: This equipment grant supported the design and construction of a subsonic variable speed wind tunnel for the study of...plasma based methods for the control of dynamic stall for helicopter rotor blades. The tunnel has a 3D positioning system and servomotor mounted below

  14. Burnout : de stand van zaken

    NARCIS (Netherlands)

    Taris, T.; Houtman, I.L.D.; Schaufeli, W.

    2013-01-01

    Dit artikel geeft een overzicht van de stand van zaken in het onderzoek naar burnout. Burnout is een syndroom van extreme vermoeidheid (uitputting), afstand nemen van het werk (distantie) en weinig vertrouwen in het eigen kunnen (verminderde competentie), waarbij de oorzaken voor deze aspecten

  15. Students dance longitudinal standing waves

    Science.gov (United States)

    Ruiz, Michael J.

    2017-05-01

    A demonstration is presented that involves students dancing longitudinal standing waves. The resulting kinaesthetic experience and visualization both contribute towards an understanding of the natural modes of vibrations in open and closed pipes. A video of this fun classroom activity is provided (http://mjtruiz.com/ped/dance/).

  16. Wavelength variation of a standing wave along a vertical spring

    Science.gov (United States)

    Welsch, Dylan; Baker, Blane

    2018-03-01

    Hand-driven resonance can be observed readily in a number of mechanical systems including thin boards, rods, strings, and springs. In order to show such behavior in the vertical spring pictured in Fig. 1, a section of spring is grasped at a location about one meter from its free end and driven by small, circular motions of the hand. At driving frequencies of a few hertz, a dramatic standing wave is generated. One of the fascinating features of this particular standing wave is that its wavelength varies along the length of the spring.

  17. Evaluation of free-stall mattress bedding treatments to reduce mastitis bacterial growth

    Energy Technology Data Exchange (ETDEWEB)

    Kristula, M.A.; Dou, Z.; Toth, J.D.; Smith, B.I.; Harvey, N.; Sabo, M. [University of Penn, Kennett Square, PA (United States)

    2008-05-15

    Bacterial counts were compared in free-stall mattresses and teat ends exposed to 5 treatments in a factorial study design on 1 dairy farm. Mattresses in five 30-cow groups were subjected to 1 of 5 bedding treatments every other day: 0.5 kg of hydrated limestone, 120 mL of commercial acidic conditioner, 1 kg of coal fly ash, 1 kg of kiln-dried wood shavings, and control (no bedding). Counts of coliforms, Klebsiella spp., Escherichia coli, and Streptococcus spp. were lowest on mattresses bedded with lime. Mattresses bedded with the commercial acidic conditioner had the next lowest counts for coliforms, Klebsiella spp., and Streptococcus spp. Wood shavings and the no-bedding control had the highest counts for coliform and Klebsiella spp. Compared with wood shavings or control, fly ash reduced the counts of coliforms, whereas for the other 3 bacterial groups, the reduction was not always significant. Streptococcus spp. counts were greatest in the control group and did not differ among the shavings and fly ash groups. Teat swab results indicated that hydrated lime was the only bedding treatment that significantly decreased the counts of both coliforms and Klebsiella spp. There were no differences in Streptococcus spp. numbers on the teats between any of the bedding treatments. Bacterial populations grew steadily on mattresses and were generally higher at 36 to 48 h than at 12 to 24 h, whereas bacterial populations on teats grew rapidly by 12 h and then remained constant. Hydrated lime was the only treatment that significantly reduced bacterial counts on both mattresses and teat ends, but it caused some skin irritation.

  18. Evaluation of rice mutant lines for resistance to brown planthopper, nilaparvata lugens stall

    International Nuclear Information System (INIS)

    Mugiono

    1985-01-01

    The most important and common insect in rice cultivation in South East Asia is brown planthopper, nilaparvata lugens stall. Seven rice mutant lines produced by the National Atomic Energy Agency, Indonesia, were tested at IRRI, the Philippines for resistance to brown planthopper. Those mutant lines were Atomita 1, 627/10-3/PsJ, Atomita 2 and 627/4-E/PsJ originated from Pelita 1/1 which was irradiated with 0.2 kGy of gamma rays and A227/2/PsJ, A227/3/PsJ and A227/5/PsJ, originated from early maturing mutant A23/PsJ/72K from irradiated Pelita 1/1 which was irradiated with 0.1 kGy of gamma rays. Evaluation of resistance was carried out by seedling bulk screening, honeydew excretion, survival and population build up tests by using brown planthopper biotype 1, 2 and 3. Results of these tests showed that the seven tested mutant lines were resistant to biotype 1 but susceptible to biotype 2. Reaction to biotype 3 showed that six mutant lines tested were moderately resistant and only one mutant of 627/4-E/PsJ was susceptible. Reactions of the mutant lines to biotype 1, 2 and 3 were different from the resistant varieties, Mudgo or ASD-7. This indicated that mutant lines might have gene(s) for resistance which differed from those of resistant varieties. The results showed that resistance to brown planthopper is possible to be introduced in Indonesian rice varieties by means of mutations. (author)

  19. Stalled repair of lesions when present within a clustered DNA damage site

    International Nuclear Information System (INIS)

    Lomax, M.E.; Cunniffe, S.; O'Neill, P.

    2003-01-01

    Ionising radiation produces clustered DNA damages (two or more lesions within one or two helical turns of the DNA) which could challenge the repair mechanism(s) of the cell. Using purified base excision repair (BER) enzymes and synthetic oligonucleotides a number of recent studies have established the excision of a lesion within clustered damage sites is compromised. Evidence will be presented that the efficiency of repair of lesions within a clustered DNA damage site is reduced, relative to that of the isolated lesions, since the lifetime of both lesions is extended by up to four fold. Simple clustered damage sites, comprised of single-strand breaks, abasic sites and base damages, one or five bases 3' or 5' to each other, were synthesised in oligonucleotides and repair carried out in mammalian cell nuclear extracts. The rate of repair of the single-strand break/abasic site within these clustered damage sites is reduced, mainly due to inhibition of the DNA ligase. The mechanism of repair of the single-strand break/abasic site shows some asymmetry. Repair appears to be by the short-patch BER pathway when the lesions are 5' to each other. In contrast, when the lesions are 3' to each other repair appears to proceed along the long-patch BER pathway. The lesions within the cluster are processed sequentially, the single-strand break/abasic site being repaired before excision of 8-oxoG, limiting the formation of double-strand breaks to <2%. Stalled processing of clustered DNA damage extends the lifetime of the lesions to an extent that could have biological consequences, e.g. if the lesions are still present during transcription and/or at replication mutations could arise

  20. Energy Expenditure of Standing Compared to Sitting While Conducting Office Tasks.

    Science.gov (United States)

    Burns, Jill; Forde, Cuisle; Dockrell, Sara

    2017-11-01

    Objectives This study aimed to investigate the energy expenditure of common office-based tasks. The objectives were to: (a) test the classification of tasks as sedentary or light-intensity physical activity and (b) compare the energy expenditure of tasks under two postural conditions (sitting and standing). Background The sedentary nature of office work has been highlighted as a health risk, and strategies to reduce sedentary behavior at work have been developed. However, there is limited evidence to guide the utilization of sit-stand workstations in the workplace for metabolic health benefits. Method A repeated measures laboratory-based study compared the energy expenditure of common office tasks in sitting and standing using indirect calorimetry ( n = 22). Four standardized tasks (sitting/standing quietly, reading, typing, sorting paper) under two postural conditions (sitting, standing) were performed in a randomized order. Results The mean energy expenditure for all tasks in sitting and standing was task in sitting compared to standing. In a repeated measures ANOVA, task ( p tasks carried out in sitting compared to standing is negligible. Application The ubiquitous use and utility of sit-stand workstations in the workplace needs to be reviewed. Notwithstanding the potential benefits of movement that may occur naturally, this study confirmed that standing as opposed to sitting does not produce a clinically important increase in energy expenditure.

  1. Transpalpebral eye enucleation in the standing horse

    DEFF Research Database (Denmark)

    Christophersen, Mogens Teken

    Transpalpebral eye enucleation in the standing horse. The Nordic Equine Veterinary Conference, Proceedings, Copenhagen. Denmark. Nov. 2011.......Transpalpebral eye enucleation in the standing horse. The Nordic Equine Veterinary Conference, Proceedings, Copenhagen. Denmark. Nov. 2011....

  2. Standing Up for Learning: A Pilot Investigation on the Neurocognitive Benefits of Stand-Biased School Desks

    Directory of Open Access Journals (Sweden)

    Ranjana K. Mehta

    2015-12-01

    Full Text Available Standing desks have proven to be effective and viable solutions to combat sedentary behavior among children during the school day in studies around the world. However, little is known regarding the potential of such interventions on cognitive outcomes in children over time. The purpose of this pilot study was to determine the neurocognitive benefits, i.e., improvements in executive functioning and working memory, of stand-biased desks and explore any associated changes in frontal brain function. 34 freshman high school students were recruited for neurocognitive testing at two time points during the school year: (1 in the fall semester and (2 in the spring semester (after 27.57 (1.63 weeks of continued exposure. Executive function and working memory was evaluated using a computerized neurocognitive test battery, and brain activation patterns of the prefrontal cortex were obtained using functional near infrared spectroscopy. Continued utilization of the stand-biased desks was associated with significant improvements in executive function and working memory capabilities. Changes in corresponding brain activation patterns were also observed. These findings provide the first preliminary evidence on the neurocognitive benefits of standing desks, which to date have focused largely on energy expenditure. Findings obtained here can drive future research with larger samples and multiple schools, with comparison groups that may in turn implicate the importance of stand-biased desks, as simple environmental changes in classrooms, on enhancing children’s cognitive functioning that drive their cognitive development and impact educational outcomes.

  3. Effect of paddock vs. stall housing on 24 hour gastric pH within the proximal and ventral equine stomach.

    Science.gov (United States)

    Husted, L; Sanchez, L C; Olsen, S N; Baptiste, K E; Merritt, A M

    2008-06-01

    Stall housing has been suggested as a risk factor for ulcer development in the equine stomach; however, the exact pathogenesis for this has not been established. To investigate the effect of 3 environmental situations (grass paddock, stall alone or stall with adjacent companion) on pH in the proximal and the ventral stomach. Six horses with permanently implanted gastric cannulae were used in a randomised, cross-over, block design. Each horse rotated through each of three 24 h environmental situations. Horses remained on their normal diet (grass hay ad libitum and grain b.i.d.) throughout the study. Intragastric pH was measured continuously for 72 h just inside the lower oesophageal sphincter (proximal stomach) and via a pH probe in the gastric cannula (ventral stomach). Neither proximal nor ventral 24 h gastric pH changed significantly between the 3 environmental situations. Mean hourly proximal gastric pH decreased significantly in the interval from 01.00-09.00 h compared to the interval from 13.00-20.00 h, regardless of environmental situation. Median hourly proximal pH only differed in the interval from 06.00-07.00 h compared to the interval 14.00-19.00 h. Neither mean nor median hourly ventral gastric pH varied significantly with the time of day. The change in housing status used in the current study did not affect acid exposure within either region of the equine stomach. The pH in the ventral stomach was uniformly stable throughout the study, while the proximal pH demonstrated a 24 h circadian pattern.

  4. Stand hazard rating for central Idaho forests

    Science.gov (United States)

    Robert Steele; Ralph E. Williams; Julie C. Weatherby; Elizabeth D. Reinhardt; James T. Hoffman; R. W. Thier

    1996-01-01

    Growing concern over sustainability of central ldaho forests has created a need to assess the health of forest stands on a relative basis. A stand hazard rating was developed as a composite of 11 individual ratings to compare the health hazards of different stands. The composite rating includes Douglas-fir beetle, mountain pine beetle, western pine beetle, spruce...

  5. Enhancing wildlife habitat when regenerating stands

    Science.gov (United States)

    Frank R., III Thompson

    1989-01-01

    Forest regeneration cuttings affect wildlife habitat more drastically than most forest management practices because a mature forest stand is replaced by a young sapling stand. Regeneration cuttings quickly provide habitat for many wildlife species but they also influence wildlife use of the new stand and adjacent areas throughout the rotation. Retaining snags, cavity...

  6. The one-leg standing radiograph

    OpenAIRE

    Pinsornsak, P.; Naratrikun, K.; Kanitnate, S.; Sangkomkamhang, T.

    2016-01-01

    Objectives The purpose of this study was to compare the joint space width between one-leg and both-legs standing radiographs in order to diagnose a primary osteoarthritis of the knee. Methods Digital radiographs of 100 medial osteoarthritic knees in 50 patients were performed. The patients had undergone one-leg standing anteroposterior (AP) views by standing on the affected leg while a both-legs standing AP view was undertaken while standing on both legs. The severity of the osteoarthritis wa...

  7. Beyond Technology, there Stands Magic

    Directory of Open Access Journals (Sweden)

    Lúcia Fernandes Lobato

    2013-07-01

    Full Text Available This article shows evidence that despite the prominent influences of the technological revolution and the spectacular panoramas on the contemporary world, magic seems to stand beyond technology. To support this hypothesis, the author investigates the images on the cinema, pointing out that to discover magic in a film, for instance, it is necessary to recognize its subjective structures disguised in the objectivity of the screen. Finally, the author indicates that in the field of image production, dance films that are created out of a cross-disciplinary effort are another by product of the fusion between art and video, born out of technological advancements.

  8. Consistent definition and application of Reineke's Stand Density Index in silviculture and stand projection

    Science.gov (United States)

    John D. Shaw; James N. Long

    2010-01-01

    Reineke’s Stand Density Index (SDI) has been available to silviculturists for over 75 years, but application of this stand metric has been inconsistent. Originally described as a measurement of relative density in single-species, even-aged stands, it has since been generalized for use in uneven-aged stands and mixed-species stands. However, methods used to establish...

  9. Theory of single-molecule controlled rotation experiments, predictions, tests, and comparison with stalling experiments in F1-ATPase.

    Science.gov (United States)

    Volkán-Kacsó, Sándor; Marcus, Rudolph A

    2016-10-25

    A recently proposed chemomechanical group transfer theory of rotary biomolecular motors is applied to treat single-molecule controlled rotation experiments. In these experiments, single-molecule fluorescence is used to measure the binding and release rate constants of nucleotides by monitoring the occupancy of binding sites. It is shown how missed events of nucleotide binding and release in these experiments can be corrected using theory, with F 1 -ATP synthase as an example. The missed events are significant when the reverse rate is very fast. Using the theory the actual rate constants in the controlled rotation experiments and the corrections are predicted from independent data, including other single-molecule rotation and ensemble biochemical experiments. The effective torsional elastic constant is found to depend on the binding/releasing nucleotide, and it is smaller for ADP than for ATP. There is a good agreement, with no adjustable parameters, between the theoretical and experimental results of controlled rotation experiments and stalling experiments, for the range of angles where the data overlap. This agreement is perhaps all the more surprising because it occurs even though the binding and release of fluorescent nucleotides is monitored at single-site occupancy concentrations, whereas the stalling and free rotation experiments have multiple-site occupancy.

  10. Thinning in artificially regenerated young beech stands

    Directory of Open Access Journals (Sweden)

    Novák Jiří

    2015-12-01

    Full Text Available Although beech stands are usually regenerated naturally, an area of up to 5,000 ha year−1 is artificially regenerated by beech in the Czech Republic annually. Unfortunately, these stands often showed insufficient stand density and, consequently, lower quality of stems. Therefore, thinning methods developed for naturally regenerated beech stands are applicable with difficulties. The paper evaluates the data from two thinning experiments established in young artificially regenerated beech stands located in different growing conditions. In both experiments, thinning resulted in the lower amount of salvage cut in following years. Positive effect of thinning on periodic stand basal area increment and on periodic diameter increment of dominant trees was found in the beech stand located at middle elevations. On the other hand, thinning effects in mountain conditions were negligible. Thinning focusing on future stand quality cannot be commonly applied in artificially regenerated beech stands because of their worse initial quality and lower density. However, these stands show good growth and response to thinning, hence their management can be focused on maximising beech wood production.

  11. Refrigeration system having standing wave compressor

    Science.gov (United States)

    Lucas, Timothy S.

    1992-01-01

    A compression-evaporation refrigeration system, wherein gaseous compression of the refrigerant is provided by a standing wave compressor. The standing wave compressor is modified so as to provide a separate subcooling system for the refrigerant, so that efficiency losses due to flashing are reduced. Subcooling occurs when heat exchange is provided between the refrigerant and a heat pumping surface, which is exposed to the standing acoustic wave within the standing wave compressor. A variable capacity and variable discharge pressure for the standing wave compressor is provided. A control circuit simultaneously varies the capacity and discharge pressure in response to changing operating conditions, thereby maintaining the minimum discharge pressure needed for condensation to occur at any time. Thus, the power consumption of the standing wave compressor is reduced and system efficiency is improved.

  12. Effects of Gestational Housing on Reproductive Performance and Behavior of Sows with Different Backfat Thickness

    Directory of Open Access Journals (Sweden)

    K. H. Kim

    2016-01-01

    Full Text Available The present study investigated the effects of back-fat thickness at d 107 of gestation and housing types during gestation on reproductive performance and behavior of sows. A total of 64 crossbred sows (Landrace×Yorkshire in their 3 to 4 parities were allotted to one of four treatments (n = 16 over two consecutive parities. During each parity, sows were assigned to two gestational housing types (stall or group housing and two level of back-fat thickness (<20 or ≥20 at d 107 of gestation. Gestating sows were transferred from gestational crates to stalls or pens (group housing 5 weeks before farrowing. All sows were moved to farrowing crates on d 109 of gestation. At weaning, back-fat thickness changes were lesser (p<0.05 in sows having back-fat thickness <20 mm than that of sows with ≥20 mm back-fat thickness at 107 d of gestation. Group housed sows had greater (p<0.05 feed intake and shorter (p<0.05 weaning-to-estrus interval than that of sows in stalls. At weaning, back-fat thickness changes were lesser (p<0.05 in group housed sows than that of sows in stalls. The number of piglets at weaning, growth rate and average daily gain were greater (p<0.05 in group housed sows than that of sows in stalls. During gestation, walking duration was more (p<0.05 in group housed sows. Group housed sows had lesser (p<0.05 farrowing duration and greater (p<0.05 eating time than that of sows in stalls. Result obtained in present study indicated that sows with ≥20 mm back-fat thickness at 107 days had better reproductive performance. Additionally, group housing of sows during last five week of gestation improved the performance and behavior and reproductive efficiency of sows.

  13. Effects of the inlet boundary layer thickness on the flow in an axial compressor (I) : hub corner stall and tip leakage flow

    International Nuclear Information System (INIS)

    Choi, Min Suk; Baek, Je Hyun; Park, Jun Young

    2005-01-01

    A three-dimensional computation was conducted to understand effects of the inlet boundary layer thickness on the internal flow in a low-speed axial compressor operating at the design condition(φ=85%) and near stall condition(φ=65%). At the design condition, the flows in the axial compressor show, independent of the inlet boundary layer thickness, similar characteristics such as the pressure distribution, size of the hub corner-stall, tip leakage flow trajectory, limiting streamlines on the blade suction surface, etc. However, as the load is increased, the hub corner-stall grows to make a large separation region at the junction of the hub and suction surface for the inlet condition with thick boundary layers at the hub and casing. Moreover, the tip leakage flow is more vortical than that observed in case of the thin inlet boundary layer and has the critical point where the trajectory of the tip leakage flow is abruptly turned into the downstream. For the inlet condition with thin boundary layers, the hub corner-stall is diminished so it is indistinguishable from the wake. The tip leakage flow leans to the leading edge more than at the design condition but has no critical point. In addition to these, the severe reverse flow, induced by both boundary layer on the blade surface and the tip leakage flow, can be found to act as the blockage of flows near the casing, resulting in heavy loss

  14. Stall/surge dynamics of a multi-stage air compressor in response to a load transient of a hybrid solid oxide fuel cell-gas turbine system

    Science.gov (United States)

    Azizi, Mohammad Ali; Brouwer, Jacob

    2017-10-01

    A better understanding of turbulent unsteady flows in gas turbine systems is necessary to design and control compressors for hybrid fuel cell-gas turbine systems. Compressor stall/surge analysis for a 4 MW hybrid solid oxide fuel cell-gas turbine system for locomotive applications is performed based upon a 1.7 MW multi-stage air compressor. Control strategies are applied to prevent operation of the hybrid SOFC-GT beyond the stall/surge lines of the compressor. Computational fluid dynamics tools are used to simulate the flow distribution and instabilities near the stall/surge line. The results show that a 1.7 MW system compressor like that of a Kawasaki gas turbine is an appropriate choice among the industrial compressors to be used in a 4 MW locomotive SOFC-GT with topping cycle design. The multi-stage radial design of the compressor enhances the ability of the compressor to maintain air flow rate during transient step-load changes. These transient step-load changes are exhibited in many potential applications for SOFC/GT systems. The compressor provides sustained air flow rate during the mild stall/surge event that occurs due to the transient step-load change that is applied, indicating that this type of compressor is well-suited for this hybrid application.

  15. Analysis of the Unsteady Flow Field in a Centrifugal Compressor from Peak Efficiency to Near Stall with Full-Annulus Simulations

    Directory of Open Access Journals (Sweden)

    Yannick Bousquet

    2014-01-01

    Full Text Available This study concerns a 2.5 pressure ratio centrifugal compressor stage consisting of a splittered unshrouded impeller and a vaned diffuser. The aim of this paper is to investigate the modifications of the flow structure when the operating point moves from peak efficiency to near stall. The investigations are based on the results of unsteady three-dimensional simulations, in a calculation domain comprising all the blade. A detailed analysis is given in the impeller inducer and in the vaned diffuser entry region through time-averaged and unsteady flow field. In the impeller inducer, this study demonstrates that the mass flow reduction from peak efficiency to near stall leads to intensification of the secondary flow effects. The low momentum fluid accumulated near the shroud interacts with the main flow through a shear layer zone. At near stall condition, the interface between the two flow structures becomes unstable leading to vortices development. In the diffuser entry region, by reducing the mass flow, the high incidence angle from the impeller exit induces a separation on the diffuser vane suction side. At near stall operating point, vorticity from the separation is shed into vortex cores which are periodically formed and convected downstream along the suction side.

  16. The Stand-alone Heliostat

    International Nuclear Information System (INIS)

    Garcia Navajas, G. I.; Egea Gea, A.

    2000-01-01

    The first Autonomous Heliostat has been developed by CIEMAT at PSA facilities in Almeria. This heliostat is an innovative approach to reducing the civil engineering work costs in heliostat fields of central tower plants. Channels, cables and other electric elements have been eliminated in the new heliostat. Thus, one 70-nr, classical T glass/metal heliostat has been adapted to include all the new stand-alone concept components. A PV system is able to drive two sun-tracking DC motors between 5 and 24Vdc, 0 and 15A. The heliostat communicates with the control room 400-m away by using a radio-modem working at 9600 baud. An anemometer, a wind switcher, light and ambient temperature sensors have been installed on the heliostat for self-protection decision-making. A PV panel integrated into the heliostat reflecting surface, eliminates cabling and other elements required for a conventional power supply. Communication lines between master control and local control have been replaced by radio-modem. Testing has validated the technical feasibility of the prototype and quantified the real consumption and efficiencies of new elements. The extra costs produced.by the autonomous concepts are compared with the cost of civil work in conventional heliostat field. (Author) 8 refs

  17. Determining maximum stand density index in mixed species stands for strategic-scale stocking assessments

    Science.gov (United States)

    Chris W. Woodall; Patrick D. Miles; John S. Vissage

    2005-01-01

    Stand density index (SDI), although developed for use in even-aged monocultures, has been used for assessing stand density in large-scale forest inventories containing diverse tree species and size distributions. To improve application of SDI in unevenaged, mixed species stands present in large-scale forest inventories, trends in maximum SDI across diameter classes...

  18. Aircraft Stand Allocation with Associated Resource Scheduling

    DEFF Research Database (Denmark)

    Justesen, Tor Fog; Larsen, Jesper; Lusby, Richard Martin

    An aircraft turn-round refers to the set of processes taking place from when an aircraft parks at its arrival stand until the time it departs from its departure stand. When handling a turn-round, the different processes involved (arrival, disembarkation of passengers, cleaning, etc.) require diff...

  19. Milk yield affects time budget in daiyr cows kept in tie-stalls

    DEFF Research Database (Denmark)

    Norring, M.; Valros, A.; Munksgaard, Lene

    2012-01-01

    Effective selection in breeding programs and improved management has increased the milk production per cow. However, the effects of the increased yield on behavior have not yet been clarified. We investigated the effect of milk yield on the time budget of 29 Finnish Ayrshire cows in the same stage...

  20. Suppression of inducer stall based on inlet recirculation in a centrifugal impeller. 1st Report. Improvement in stall limit by ring groove arrangement; Enshin haneguruma iriguchi junkanryu ni yoru inducer shissoku no yokusei. 1. kanjoko ni yoru shissoku genkai no kaizen

    Energy Technology Data Exchange (ETDEWEB)

    Ueki, H.; Ishida, M.; Sakaguchi, D.; Sun, Z. [Nagasaki University, Nagasaki (Japan). Faculty of Engineering

    2000-07-25

    A ring groove arrangement is proposed to suppress unstable flow or surge in a centrifugal blower. The ring groove arrangement connects the upstream position of impeller inlet and the inducer throat tip through a bypass. The recirculation flow 'vas formed by the pressure difference between the two positions, and the recirculation flow rate was changed by increasing the ring groove widths. The inlet recirculation results in a decrease in the flow rate of unstable flow inception, and an up to 800 improvement in stall limit was obtained by the ring groove arrangement at a small expense of the delivery pressure drop. The improvement of stall limit in the present experiment seems to be mainly due to decrease in flow incidence based on the inlet recirculation flow. Tre flow incidence decreases more as the recirculation flow rate increases, thus resulting in a larger improvement in stall limit. (author)

  1. Stalling for Time: It's Not the Magnitude, but the Way Neurons Fire that Matters.

    Science.gov (United States)

    Scott, Stephen H

    2017-07-05

    In this issue of Neuron, Stavisky et al. (2017) demonstrate that visual feedback in M1 during reaching initially reflects a specific pattern of neural activity that does not generate motor output and then is altered to a pattern that does generate motor output. This switch likely provides time for the motor system to consider various behavioral factors when specifying the appropriate motor response during voluntary motor actions. Copyright © 2017 Elsevier Inc. All rights reserved.

  2. Dynamics of dense direct-seeded stands of southern pines

    Science.gov (United States)

    J.C.G. Goelz

    2006-01-01

    Direct seeding of southern pines is an effective method of artificial regeneration, producing extremely dense stands when survival exceeds expectations. Long-term studies of dense direct-seeded stands provide ideal data for exploring development of stands as they approach the limit of maximum stand density. I present data from seven studies with ages of stands ranging...

  3. Behavior analysis, from grinding or not of the teeth of piglets in nursery

    Directory of Open Access Journals (Sweden)

    Gisele Dela Ricci

    2013-12-01

    . Analyzing the behavior of piglets from varying treatments, shift and week, we found an important effect in all proposals. After confronting variables such as treatment and day shift, only the behavior of eating and sitting had no significant effect. But when contrasted treatment and week, important behaviors such as exploratory and playfulness didn't show significant effect. When evaluating individual behavior the playfulness showed significant effect when related to different kinds of handling of teeth. The standing and playful behavior, important evidence of comfort and stress of animals, were the ones which had no significant effect when the variables treatment x week x shift were opposed. The stereotyped behavior, important for the welfare of confined animals, showed no significant effect only for opposing variables: week x shift and treatment, indicating a high correlation between treatment, time of confinement and lack of entertainment of confined animals. Significant effect was found for agonistic behavior in all opposing variables, indicating normal behavior of piglets, both in the early days of birth and the following weeks, due to increased body and consequent reduction in the physical space of the stall. It is concluded from the treatments that the grinding of piglets teeth in the nursery is effective for reducing aggressive behavior and there were fewer animals with injuries in pig farms.

  4. Recent advances in standing equine orthopedic surgery.

    Science.gov (United States)

    O'Brien, Thomas; Hunt, Robert J

    2014-04-01

    In all surgeries with the patient standing under chemical and physical restraint, patient compliance is of the utmost importance. All fractures of the third metacarpal or metatarsal condyles and sagittal fracture of the first phalanx are not amenable to internal fixation with the horse standing, and young unhandled horses may not have a suitable disposition for standing surgical treatment of septic pedal osteitis, or implantation and removal of transphyseal screws. Previous operator experience in performing the procedure or technique under general anesthesia is beneficial. Appreciation of appropriate topographic anatomic landmarks is important, and intraoperative radiographic control is useful. Copyright © 2014 Elsevier Inc. All rights reserved.

  5. Basic Stand Alone Medicare Outpatient Procedures PUF

    Data.gov (United States)

    U.S. Department of Health & Human Services — This release contains the Basic Stand Alone (BSA) Outpatient Procedures Public Use Files (PUF) with information from Medicare outpatient claims. The CMS BSA...

  6. Basic Stand Alone Medicare Hospice Beneficiary PUF

    Data.gov (United States)

    U.S. Department of Health & Human Services — This release contains the Basic Stand Alone (BSA) Hospice Beneficiary Public Use Files (PUF) with information from Medicare hospice claims. The CMS BSA Hospice...

  7. Basic Stand Alone Carrier Line Items PUF

    Data.gov (United States)

    U.S. Department of Health & Human Services — This release contains the Basic Stand Alone (BSA) Carrier Line Items Public Use Files (PUF) with information from Medicare Carrier claims. The CMS BSA Carrier Line...

  8. Basic Stand Alone Medicare Inpatient Claims PUF

    Data.gov (United States)

    U.S. Department of Health & Human Services — This release contains the Basic Stand Alone (BSA) Inpatient Public Use Files (PUF) named CMS 2008 BSA Inpatient Claims PUF with information from 2008 Medicare...

  9. Compressor Load Stand: Commissioning and Control Strategies

    National Research Council Canada - National Science Library

    Causey, Andrew

    1998-01-01

    .... The purpose of this research project was to commission this load stand, which includes setting up the hardware, setting up a control system, a data acquisition system, and an automatic test sequence system...

  10. RLC Forest Stand Carbon Map of Russia

    Data.gov (United States)

    National Aeronautics and Space Administration — This dataset is a 1:15 million scale map of forest stand carbon for the land area of Russia (Stone et al., 2000). The objective was to create a first approximation...

  11. RLC Forest Stand Carbon Map of Russia

    Data.gov (United States)

    National Aeronautics and Space Administration — ABSTRACT: This dataset is a 1:15 million scale map of forest stand carbon for the land area of Russia (Stone et al., 2000). The objective was to create a first...

  12. Minnesota DNR Forest Stand Inventory Version 2

    Data.gov (United States)

    Minnesota Department of Natural Resources — This layer is a digital inventory of individual forest stands. The data is collected by DNR Foresters in each DNR Forestry Administrative Area, and is updated on a...

  13. Commanding Officer's Standing Orders: A Powerful and Unique Genre

    National Research Council Canada - National Science Library

    Turner, Kyle H

    2006-01-01

    Commanding Officer's Standing Orders are critical to shipboard watch standing. Written by the captain and used by watch standers, Standing Orders perform many unique and powerful functions aboard ships...

  14. Species composition of developing Central Appalachian hardwood stands following clearcutting

    Science.gov (United States)

    Lance A. Vickers; Thomas Fox

    2015-01-01

    This study examined the species composition of 47 paired stands on submesic sites on the Appalachian Plateau of West Virginia. Paired stands consisted of a mature stand adjacent to a young clearcut that was

  15. Operating systems: Internals and design principles, 5th ed. William Stallings : Prentice Hall, 2005. ISBN: 0-13-147954-7

    OpenAIRE

    Molinari, Lía Hebe

    2007-01-01

    As a professor of the Operating Systems subject, I can say that for many years the book “Operating Systems Concepts” by Avi Silberschatz et al. was considered as the unquestionable number one in the subject’s bibliography. The book we are talking about now, the new edition of “Operating Systems” by William Stallings, is thought to be the possible replacement of the first one.

  16. The elastic transfer model of angular rate modulation in F1-ATPase stalling and controlled rotation experiments

    Science.gov (United States)

    Volkán-Kacsó, S.

    2017-06-01

    The recent experimental, theoretical and computational advances in the field of F1-ATPase single-molecule microscopy are briefly surveyed. The role of theory is revealed in the statistical analysis, interpretation and prediction of single-molecule experimental trajectories, and in linking them with atomistic simulations. In particular, a theoretical model of elastically coupled molecular group transfer is reviewed and a detailed method for its application in stalling and controlled rotation experiments is provided. It is shown how the model can predict, using previous experiments, the rates of ligand binding/release processes (steps) and their exponential dependence on rotor angle in these experiments. The concept of Brønsted slopes is reviewed in the context of the single-molecule experiments, and the rate versus rotor angle relations are explained using the elastic model. These experimental data are treated in terms of the effect of thermodynamic driving forces on the rates assuming that the rotor shaft is elastically coupled to stator ring subunits in which the steps occur. In the application of the group transfer model on an extended angular range processes leading up to the transfer are discussed. Implications for large-scale atomistic simulation are suggested for the treatment of torque-generating steps.

  17. Exploiting translational stalling peptides in an effort to extend azithromycin interaction within the prokaryotic ribosome nascent peptide exit tunnel.

    Science.gov (United States)

    Washington, Arren Z; Tapadar, Subhasish; George, Alex; Oyelere, Adegboyega K

    2015-08-15

    The ribosome is the primary protein synthesis machine in the cell and is a target for treatment of a variety of diseases including bacterial infection and cancer. The ribosomal peptide exit tunnel, the route of egress for the nascent peptide, is an inviting site for drug design. Toward a rational engagement of the nascent peptide components for the design of small molecule inhibitors of ribosome function, we designed and disclosed herein a set of N-10 indole functionalized azithromycin analogs. The indole moiety of these compounds is designed to mimic the translation stalling interaction of SecM W155 side-chain with the prokaryotic (Escherichia coli) ribosome A751 residue. Many of these N-10 functionalized compounds have enhanced translation inhibition activities against E. coli ribosome relative to azithromycin while a subset inhibited the growth of representative susceptible bacteria strains to about the same extent as azithromycin. Moreover, the inclusion of bovine serum in the bacterial growth media enhanced the anti-bacterial potency of the N-10 functionalized azithromycin analogs by as high as 10-fold. Published by Elsevier Ltd.

  18. A study of the drooped leading edge airfoil. [on wind tunnel models to reduce spin entry after stall

    Science.gov (United States)

    Anderson, J. D., Jr.; Barlow, J. B.

    1979-01-01

    Wind tunnel tests were conducted to examine various aspects of the drooped-leading edge airfoil which reduces the tendency for an airplane to enter a spin after stall occurs. Three baseline models were used for tests of two dimensional models: NACA 0015, 0014.6, and 0014.2. The 14.6% and 14.2% models were derived from NACA 0015 sections by increasing the chord and matching the profiles aft section. Force, balance data (lift, drag, pitching moment) were obtained for each model at a free-steam Reynold's number of 2.66 x 10 to the 6th power/m. In addition, oil flow visualization tests were performed at various angles of attack. An existing NACA 64 sub 1 A211 airfoil was used in a second series of tests. The leading edge flap was segmented in three parts which allowed various baseline/drooped leading edge configurations to be tested. Force balance and flow visualization tests were completer at chord Renolds numbers of 0.44 x 10 to the 6th power, 1.4 x 10 to the 6th power, and 2.11 x 10 to the 6th power. Test results are included.

  19. Using Nature-Based Rehabilitation to Restart a Stalled Process of Rehabilitation in Individuals with Stress-Related Mental Illness

    Directory of Open Access Journals (Sweden)

    Eva Sahlin

    2015-02-01

    Full Text Available After a period of decrease, sick leave in Sweden due to psychiatric diagnoses is on the increase. The lack of established rehabilitation programmes for patients with stress-related mental disorders (SRMD has opened up for the use of garden/nature in a multimodal rehabilitation context (Nature-Based Rehabilitation, NBR. Region Västra Götaland (VGR started an NBR to offer additional rehabilitation for its employees on long-term sick leave due to SRMD, where initial care had not been sufficient. The aim was to explore whether the mental health and well-being of NBR participants had improved at the end of the NBR and at three follow-ups, and to explore the development of sick leave and health care utilization according to the NBR model (n = 57 and an occupational health service (OHS model (n = 45. Self-assessment instruments for measuring burnout, depression, anxiety and wellbeing, and data from regional and national registers were used. Results showed decreased scores on burnout, depression and anxiety, and increased well-being scores and significantly reduced health care utilization in the NBR group. A large movement from ordinary sickness benefit to rehabilitation benefit was observed, which was not observed in the OHS group. The two groups were in different rehabilitation phases, which limited comparisons. The results point to beneficial effects of using NBR for this patient group and for enhancing a stalled rehabilitation process.

  20. Investigating dynamic stall, 3-D and rotational effects on wind turbine blades by means of an unsteady quasi-3D Navier-Stokes solver

    Energy Technology Data Exchange (ETDEWEB)

    Chaviaropoulos, P.K. [CRES-Center for Renewable Energy Sources, Pikermi Attiki (Greece)

    1997-08-01

    The blade element codes provide surprisingly accurate predictions of the aerodynamic loads provided that they are `fed` with proper lift and drag - incidence curves for the profiles mounted on the rotor blades. The evident question is how one can obtain such data. It is common experience that the use of the mostly available steady two-dimensional profile data may lead to serious discrepancies between measured and simulated loads. Although several correction techniques have been proposed as a remedy during the last years, from simplified dynamic stall models suitably tuned for wind turbines to 3-D correction schemes for profile data, the problem is by no means over-passed. Especially for the three-dimensional effects it seems that part of the difficulty is due to our limited understanding of the physical mechanism which is responsible for the extra loading of the inner part of the blades. Recognizing the importance of the above aspects two relevant Joule projects have been launched, the concluded `Dynamic Stall and 3-D Effects` JOU2-CT93-0345 and the ongoing `VISCWIND` JOR3-CT95-0007 project. Part of the activities in the first and all the activities in the second project are devoted to the identification and quantification of the dynamic stall and three-dimensional effects experienced by the wind turbine blades using Navier-Stokes computations. The contribution of CRES in these two projects is briefly presented in this paper. (EG)

  1. Caracterização do microambiente em secção transversal de um galpão do tipo "free-stall" orientado na direção norte-sul Environment characterization in transversal direction in a free-stall housing oriented to north-south direction

    Directory of Open Access Journals (Sweden)

    Alessandro T. Campos

    2004-04-01

    Full Text Available O trabalho teve o objetivo de caracterizar o microambiente climático das baias de um galpão de confinamento para gado leiteiro, modelo "free-stall", no sentido transversal da instalação. O "free-stall" é orientado na direção norte-sul, localizado em Marechal Cândido Rondon, região Oeste do Paraná, com capacidade para abrigar 40 vacas em lactação (40 baias. Visando à determinação do Índice de Temperatura do Globo e Umidade (ITGU e da Carga Térmica de Radiação (CTR, foram instalados quatro globos negros, no centro de baias dispostas no sent ido transversal, dispondo dois globos no lado oeste e dois globos no lado leste (separados pelo corredor de alimentação. Lateralmente ao galpão, no lado leste, havia vegetação a 4 m da instalação, que promovia sombreamento nas primeiras horas do dia. Pode-se concluir que, nas primeiras horas do dia, não há diferença significativa entre os valores de ITGU e CTR encontrados, indicando que o sombreamento, devido à vegetação, foi capaz de amenizar os efeitos da radiação solar. Às 17 h 30 min, verificou-se que há ocorrência de maiores valores, tanto de ITGU quanto de CTR, nas baias localizadas no lado oeste do "free-stall".This work aimed to characterize the microclimatic conditions of the stalls of a free-stall model confinement building for dairy cattle in the transversal direction of the installation. Free-stall building was oriented to north-south direction, located in Marechal Cândido Rondon, west of Paraná State -Brazil, with a capacity of 40 dairy cows (40 stalls. In order to determine the Black-Globe-Humidity Index (BGHI and Radiant Heat Load (RHL, four black globes were installed in the center of stalls disposed in the transversal direction, disposing two globes in the west side and two globes in the east side (separated by the feed alley. At the building sidelong, east side, there was a four meter distant vegetation, that promoted shading in the first hours of the day

  2. Perdas econômicas ocasionadas pelas enfermidades podais em vacas leiteiras confinadas em sistema free stall Economic losses caused by sequels of lameness in free-stall-housed dairy cows

    Directory of Open Access Journals (Sweden)

    R.C. Souza

    2006-12-01

    Full Text Available Avaliaram-se 55 casos clínicos de manqueira em um rebanho de 100 vacas em lactação confinadas em sistema de free stall, durante um ano. As afecções mais observadas foram abscessos de sola e talão, úlcera de sola e dermatite digital que representaram 87,3% (48/55 das ocorrências. O tratamento empregado mostrou-se satisfatório com recuperação de todos os animais tratados com 24,5 dias, em média, sem ocorrência de descarte. O custo com tratamento e redução na produção de leite foi de US$95.80/vaca, o que representou US$52.69 por vaca alojada/ano. Quando se computaram as perdas reprodutivas e com mastite, obtiveram-se US$227.94 adicionais em vaca com problema de manqueira. O custo adicional anual total no rebanho decorrente de seqüelas de manqueira foi de US$12,536.70, que representou US$125.36 por vaca alojada/ano. O período de serviço e o número de serviços por concepção em vacas com problemas de manqueira e normais foram 266 e 200,5 dias e 4,3 e 3,3 serviços, respectivamente. As incidências de mastite e metrite na mesma ordem de citação anterior foram 60% e 25% e 29% e 12,5%.Fifty-five clinical cases of lameness were evaluated in 100 lactating cows housed in a free-stall system during one year. The most observed affections were sole and heel abscesses, sole ulcers and digital dermatitis that accounted for 87.3% (48/55 of the occurrences. The treated cows showed satisfactory recovery (24.5 average days without culling. The total individual cost including treatment and reduction of milk production was US$95.80/cow or US$52.69 per housed cow/year. When reproductive losses and mastitis were considered an additional cost of US$227.94 per lameness cow was estimated. The total additional annual cost from sequels of lameness was US$12.536.70 or US$152.36 per housed cow/year. The number of days open and the number of services per conception in lameness and normal cows were, respectively, 266 and 200.5 days and 4.3 and 3

  3. A user's guide to the combined stand prognosis and Douglas-fir tussock moth outbreak model

    Science.gov (United States)

    Robert A. Monserud; Nicholas L. Crookston

    1982-01-01

    Documentation is given for using a simulation model combining the Stand Prognosis Model and the Douglas-fir Tussock Moth Outbreak Model. Four major areas are addressed: (1) an overview and discussion of the combined model; (2) description of input options; (3) discussion of model output, and (4) numerous examples illustrating model behavior and sensitivity.

  4. Red-Cockaded Woodpecker male/female foraging differences in young forest stands

    Science.gov (United States)

    Kathleen E. Franzreb

    2010-01-01

    The Red-cockaded Woodpecker (Picoides borealis) is an endangered species endemic to pine (Pinusspp.) forests of the southeastern United States. I examined Red-cockaded Woodpecker foraging behavior to learn if there were male/female differences at the Savannah River Site, South Carolina. The study was conducted in largely young forest stands (,50 years of age) in...

  5. The Influence of Residual Stand Densities on Regeneration in Sugar Maple Stands

    Science.gov (United States)

    Carl H. Tubbs

    1968-01-01

    Studies of regeneration 2, 5, and 10 years after cutting mature and overmature sugar maple stands to several residual densities show that (1) sugar maple is still the predominant species under all stand densities (2) nearly all regeneration reaching larger size classes became established before cutting (3) heavier cuttings (30, 50, and 70 square feet) are more rapidly...

  6. High throughput electric thruster test stand design

    International Nuclear Information System (INIS)

    Guss, W.C.; Myer, R.C.; Post, R.S.; Torti, R.P.

    1987-05-01

    The difficulty in developing a test stand for electric (MPD or ion) thrusters involves the following issues: Pumping requirements for high speed and throughput, power supply requirements and associated waste heat removal, erosion of surfaces in contact with the plume and the lack of plume data required for test stand design. The pumping requirements which are dealt with here, have been so difficult to meet that little progress has been made on long pulse issues. A design is proposed using a surface pumping technology, titanium gettering, that has been developed in fusion research laboratories. The getter pumping must be used in a differential pumping scheme to handle the throughput and pumping speed requirements. By starting with short pulse experiments, plume data can be accumulated for the more critical design of the continuous operation test stand for MPD thruster life time tests

  7. Static standing, dynamic standing and spasticity in individuals with spinal cord injury.

    Science.gov (United States)

    Sadeghi, M; Mclvor, J; Finlayson, H; Sawatzky, B

    2016-05-01

    This was a cross-over efficacy study design. To determine spasticity differences between static and dynamic standing training in individuals with spinal cord injury (SCI). Vancouver, Canada. Ten individuals with SCI who could stand with or without bracing or supports participated in both dynamic and static standing training (one session each, 2 days apart) using a Segway. The primary outcome was spasticity as measured by Visual Analog Scale (VAS), Modified Ashworth Scale (MAS) and electromyography (EMG) of the quadriceps, hamstrings, adductors and gastrocnemius. There was no statistically detectable difference in spasticity between dynamic and static standing training in individuals with SCI as measured by VAS, MAS or EMG, although there was a trend towards decreased spasticity after the dynamic training. There is no significant difference in spasticity outcomes between static and dynamic standing training on a Segway for individuals with SCI. This research was funded by Natural Sciences and Engineering Research Council of Canada and International Collaboration on Repair Discoveries.

  8. Standing sausage modes in curved coronal slabs

    Science.gov (United States)

    Pascoe, D. J.; Nakariakov, V. M.

    2016-09-01

    Context. Magnetohydrodynamic waveguides such as dense coronal loops can support standing modes. The ratios of the periods of oscillations for different longitudinal harmonics depend on the dispersive nature of the waveguide and so may be used as a seismological tool to determine coronal parameters. Aims: We extend models of standing sausage modes in low β coronal loops to include the effects of loop curvature. The behaviour of standing sausage modes in this geometry is used to explain the properties of observed oscillations that cannot be accounted for using straight loop models. Methods: We perform 2D numerical simulations of an oscillating coronal loop, modelled as a dense slab embedded in a potential magnetic field. The loop is field-aligned and so experiences expansion with height in addition to being curved. Standing sausage modes are excited by compressive perturbations of the loop and their properties are studied. Results: The spatial profiles of standing sausage modes are found to be modified by the expanding loop geometry typical for flaring loops and modelled by a potential magnetic field in our simulations. Longitudinal harmonics of order n > 1 have anti-nodes that are shifted towards the loop apex and the amplitude of anti-nodes near the loop apex is smaller than those near the loop footpoints. Conclusions: We find that the observation of standing sausage modes by the Nobeyama Radioheliograph in a flaring coronal loop on 12 January 2000 is consistent with interpretation in terms of the global mode (n = 1) and third harmonic (n = 3). This interpretation accounts for the period ratio and spatial structure of the observed oscillations.

  9. Future directions in standing-wave photoemission

    International Nuclear Information System (INIS)

    Gray, Alexander X.

    2014-01-01

    Highlights: • Probing magnetic properties at the buried interface with SW-MCD. • Probing electronic structure at the buried interface with resonant SW-XPS and SW-HAXPES. • Probing momentum-resolved electronic structure at a buried interface with SWARPES. • Adding depth resolution to photoemission microscopy with standing-wave excitation. • Standing-wave localization, total reflection and waveguide effects. - Abstract: Over the past decade, standing-wave photoemission (SW-XPS) has evolved into a powerful and versatile non-destructive technique for probing element-specific electronic, magnetic, and structural properties of buried layers and interfaces with sub-nanometer depth resolution. In this article, I will discuss several promising future directions in this emergent field stemming from experimental and theoretical studies wherein SW-XPS is combined with other X-ray techniques, such as magnetic circular dichroism (MCD), hard X-ray photoemission spectroscopy (HAXPES), angle-resolved photoemission (ARPES), and photoemission microscopy (PEEM), adding extra dimensions to the measurement and thus widening the scope of scientific and technological questions accessible via the use of standing waves. I will further discuss examples of recently developed methods for X-ray standing-wave data analysis, which yield layer-resolved matrix-element-weighted densities of states at interfaces as well as Ångstrom-level changes in periodicity of synthetic superlattices. Finally, I will explore the possibility of localizing the standing waves near the surface and within a buried layer by the use of aperiodic superlattices, total reflection, and X-ray waveguide effects

  10. The WWER fuel element safety research under the design and heavy accident imitation on the 'PARAMETR' stand

    International Nuclear Information System (INIS)

    Deniskin, V.P.; Nalivaev, V.I.; Parshin, N. Ya.; Fedik, I.I.

    2000-01-01

    Analysis of fuel element behavior in the course of the design and heavy accidents is the component of reactor facility safety prevention. Many tasks of fuel element behavior research may be solved with the help of thermophysical stands. One of such stands implemented in 1991 was thermophysical stand 'PARAMETER'.Several experiments on model assemblies chiefly imitating both heavy accident and design basic accident have already been conducted in 'PARAMETER' stand. There were obtained data about fuel claddings seal failure and deformation condition. In particular it was defined that seal failure of all fuel claddings occurs on stage of fuel element warming, in temperature range (770-900) degree celsius and almost does not depend on inner pressure level

  11. Learning Upright Standing on a Multiaxial Balance Board.

    Directory of Open Access Journals (Sweden)

    Maria Stella Valle

    Full Text Available Upright stance on a balance board is a skill requiring complex rearrangement of the postural control. Despite the large use of these boards in training the standing posture, a comprehensive analysis of the learning process underlying the control of these devices is lacking. In this paper learning to maintain a stable stance on a multiaxial oscillating board was studied by analyzing performance changes over short and long periods. Healthy participants were asked to keep the board orientation as horizontal as possible for 20 sec, performing two sessions of 8 trials separated by 15-min pause. Memory consolidation was tested one week later. Amplitude and variability of the oscillations around horizontal plane and area and sway path of the board displacement decreased rapidly over the first session. The performance was stable during the second session, and retained after 1 week. A similar behavior was observed in the anterior-posterior and medial-lateral directions for amplitude and variability parameters, with less stable balance in the anterior-posterior direction. Approximate entropy and mean power frequency, assessing temporal dynamics and frequency content of oscillations, changed only in the anterior-posterior direction during the retention test. Overall, the ability to stand on a balance board is rapidly acquired, and retained for long time. The asymmetric stability between anterior-posterior and medial-lateral directions replicates a structure observed in other standing stances, suggesting a possible transfer from previous postural experiences. Conversely, changes in the temporal dynamics and the frequency content could be associated with new postural strategies developed later during memory consolidation.

  12. Asymmetry of the free-standing polyelectrolyte multilayers

    Science.gov (United States)

    Yu, Li; Yuan, Weichang; Liu, Xiaokong; Xu, Xintong; Ruan, Shuangchen

    2017-11-01

    Free-standing polyelectrolyte multilayers (PEMs) triggered an intense research effort to develop functional capsules and membranes, nevertheless, the comprehensive understanding of the surface distinctions between the two sides of the free-standing PEMs has been rarely studied. In this paper, we demonstrate the asymmetric surface morphologies, compositions, surface charge and wetting properties of the free-standing PEMs made of alternating deposition of poly(diallyldimethylammonium chloride) (PDDA) and poly(styrenesulfonate) (PSS) on uncharged trimethoxy (octyl) silane modified silicon wafer (TMOS-Si) substrates. The growth behaviors (e.g., linear or exponential growth) of the (PDDA/PSS)n PEMs deposited on TMOS-Si substrates are similar to those deposited on negatively charged substrates except a slower evolution in morphology and thickness, evidenced by atomic force microscopy (AFM) and ellipsometry. The surface charge of the two sides can be tuned as +/+, -/-, and +/- by selecting the first and the terminate layer of the polyelectrolyte during the deposition process, indicated by X-ray photoelectron spectroscopy (XPS) and the surface zeta potential measured by spinning disk method. Further, water contact angle measurements exhibit a strong difference between the back side (the bottom side that was initially contacted with the substrate) (74 ± 4°) and front side (33 ± 2° and 48 ± 3° for PDDA and PSS as the outmost layer, respectively) of the PEMs. The larger water contact angle of the back side is probably resulted from the orientation of the alkyl chains of the polyelectrolytes as the hydrophobic-hydrophobic interactions played significant roles in deposition of a polyelectrolyte onto an uncharged substrate. This paper may gain new insights on understanding surface properties of the PEMs.

  13. Sliding and Lower Limb Mechanics during Sit-Stand-Sit Transitions with a Standing Wheelchair

    Directory of Open Access Journals (Sweden)

    Yu-Sheng Yang

    2014-01-01

    Full Text Available Purpose. This study aimed to investigate the shear displacement between the body and backrest/seat, range of motion (ROM, and force acting on the lower limb joints during sit-stand-sit transitions by operating an electric-powered standing wheelchair. Methods and Materials. The amounts of sliding along the backrest and the seat plane, ROM of lower limb joints, and force acting on the knee/foot were measured in twenty-four people with paraplegia. Results. Without an antishear mechanism, the shear displacement was approximately 9 cm between the user’s body and the backrest/seat surfaces. During standing up, the user’s back slid down and the thigh was displaced rearward, but they moved in opposite directions when wheelchair sat back down. A minimum of 60 degrees of ROM at the hip and knee was needed during sit-stand-sit transitions. The maximal resultant forces acting on the knee restraints could reach 23.5% of body weight. Conclusion. Sliding between the body and backrest/seat occurred while transitioning from sitting to standing and vice versa. A certain amount of ROM at lower limb joints and force acting on the knee was necessitated during sit-stand-sit transitions. Careful consideration needs to be given to who the user of the electric powered standing wheelchair is.

  14. Guitar Strings as Standing Waves: A Demonstration

    Science.gov (United States)

    Davis, Michael

    2007-01-01

    The study demonstrates the induction of one-dimensional standing waves, called "natural-harmonics" on a guitar to provide a unique tone. The analysis shows that a normally complex vibration is composed of a number of simple and discrete vibrations.

  15. Criteria for fitness to stand criminal trial

    African Journals Online (AJOL)

    fitness to stand trial. The proposed criteria. used as a single rating instrument, are cost·effective in tenns of time and staff, avoid unnecessary hospitalisation and ... health professionals. A preliminary questionnaire comprising the following components was compiled, viz.: (I) legal Items; VI) psychiatric items; Vii) special ...

  16. IMS Learning Design: De stand van zaken

    NARCIS (Netherlands)

    Tattersall, Colin; Manderveld, Jocelyn

    2005-01-01

    Tattersall, C. & Manderveld, J. (2004) IMS Learning Design: De stand van zaken In: Gorissen, P., Manderveld, J., Benneker, F. & Cordewener, B. Leertechnologie in de Lage Landen (pp. 31-33). Utrecht, Stichting Surf. Ook beschikbaar in dspace: http://hdl.handle.net/1820/270

  17. Large optics inspection, tilting, and washing stand

    Science.gov (United States)

    Ayers, Marion Jay [Brentwood, CA; Ayers, Shannon Lee [Brentwood, CA

    2010-08-24

    A large optics stand provides a risk free means of safely tilting large optics with ease and a method of safely tilting large optics with ease. The optics are supported in the horizontal position by pads. In the vertical plane the optics are supported by saddles that evenly distribute the optics weight over a large area.

  18. La stand up comedy e il parresiasta

    Directory of Open Access Journals (Sweden)

    Simone Cantino

    2017-02-01

    Full Text Available In the present essay the author examines the american Stand up comedy as a form of art and entertainement which involves many different aspects (for instance One man show and Preaching. The intent of this essay is to look into the correlation that the comedian creates between laughter and the search for truth (both personal and universal. By comparing different bits and excerpts taken from the comedy acts of american authors such as Lenn Bruce, George Carlin and Bill Hicks, the author finds a relation between the elements of satire in the Stand up comedy genre and the concept of ‘parrhesia’ and parrhesiast. The purpose of the essay is to demonstrate how the peculiar figure of the stand up comedian can assume a precise philosophical and ethical role. The act of showing the people their own hypocrisies and self deceptions by using the laughter is a way  to stimulate a reflection and, potentially, determine a growth of self awareness in the mind of the people of the audience. Stand up comedy should be seen not only as a form of entertainment, but also as a way for developing a critical thinking and can be considered, in some cases, a tool for achieving some kind of revelation and change.

  19. Long standing intra oral acid burn

    NARCIS (Netherlands)

    Kumar, V.V.; Ebenezer, S.; Lobbezoo, F.

    2015-01-01

    Oral burn due to ingestion of corrosive substances can bring about debilitating consequences. It often brings mortality, and the survivors can have severe impairment of functions, especially in relation to the stomatognathic and gastrointestinal systems. This article presents a long-standing case

  20. Direct sampling for stand density index

    Science.gov (United States)

    Mark J. Ducey; Harry T. Valentine

    2008-01-01

    A direct method of estimating stand density index in the field, without complex calculations, would be useful in a variety of silvicultural situations. We present just such a method. The approach uses an ordinary prism or other angle gauge, but it involves deliberately "pushing the point" or, in some cases, "pulling the point." This adjusts the...

  1. Steel erected at A-3 Test Stand

    Science.gov (United States)

    2008-01-01

    Fabricated steel began arriving by truck Oct. 24 for construction of the A-3 Test Stand that will be used to test the engine for the nation's next generation of moon rockets. Within days workers from Lafayette Steel Erector Inc. began assembling the 16 steel stages needed on the foundation and footings poured in the previous year.

  2. AA, wide quadrupole on measurement stand

    CERN Multimedia

    CERN PhotoLab

    1981-01-01

    Please look up 8101024 and 8103203 first. Wide quadrupole (QFW, QDW) with end-shims and shimming washers on the measurement stand. With the measurement coil one measured the harmonics of the magnetic field, determined the magnetic centre, and catalogued the effect of washer constellations.

  3. Standing waves in fiber-optic interferometers

    NARCIS (Netherlands)

    De Haan, V.; Santbergen, R.; Tijssen, M.; Zeman, M.

    2011-01-01

    A study is presented giving the response of three types of fiber-optic interferometers by which a standing wave through an object is investigated. The three types are a Sagnac, Mach–Zehnder and Michelson–Morley interferometer. The response of the Mach–Zehnder interferometer is similar to the Sagnac

  4. Photovoltaic Module Simulink Model for a Stand-alone PV System

    Science.gov (United States)

    Qi, Chen; Ming, Zhu

    Photovoltaic(PV) Module is indispensable of a stand-alone PV system. In this paper, a one-diode equivalent circuit-based versatile simulation model in the form of masked block PV module is proposed. By the model, it is allowed to estimate behavior of PV module with respect changes on irradiance intensity, ambient temperature and parameters of the PV module. In addition, the model is capable of function of Maximum Power Point Tracking (MPPT) which can be used in the dynamic simulation of stand-alone PV systems.

  5. [Management of the dry and transition periods of dairy cattle in free stall housing systems in Lower Saxony. Part 1: Farm management. Teil 1: Betriebsmanagement].

    Science.gov (United States)

    Oetting-Neumann, Pamela; Hoedemaker, Martina

    2017-10-17

    Describing husbandry and management of dairy cows during the dry and transition periods on farms of different sizes in Lower Saxony, Germany. A total of 51 dairy farms were visited and asked via questionnaire about the husbandry and management in the following categories: general operating data, stable and husbandry of milking cows, dry cows, transition cows and the youngstock, pasture management, feeding, health data and prophylactic treatments. In addition, during a farm inspection, data on cow comfort were collected. German Holstein was the predominant breed on the dairy farms. Most cattle were kept in three-rowed free-stall housing systems (74%) with straw bedding (47%) without division in productivity groups (59%). The dry cows were most frequently separated in two groups (68%) in free-stall housing systems (68%). The heifers were similarly mainly kept in free-stall housing systems (67%) and were mostly separated according to their reproductive status (74%). On 29% of the farms, pasture grazing was not practiced at any time. On 80% of the farms, cows were fed a mixed ration with computerized concentrate supplementation and on 68% of the farms biphasic dry cow diets were used. The most frequently stated health problems were of the limb and claw (61%). Prophylaxis of ketosis was practiced on 21% of the farms and milk-fever prophylaxis on 12% of the farms, both for each individual cow around calving. Husbandry and management on farms differ widely and are still in need of optimization with respect to barn concepts, implementation of production groups and feeding, as well as veterinary consultation with respect to health problems and prophylactic measures.

  6. Hydrogen Gas Production in a Stand-Alone Wind Farm

    Directory of Open Access Journals (Sweden)

    M. Naziry Kordkandy

    2017-04-01

    Full Text Available This paper is analyzing the operation of a stand-alone wind farm with variable speed turbines, permanent magnet synchronous generators (PMSG and a system for converting wind energy during wind speed variations. On this paper, the design and modeling of a wind system which uses PMSG’s to provide the required power of a hydrogen gas electrolyzer system, is discussed. This wind farm consists of three wind turbines, boost DC-DC converters, diode full bridge rectifiers, permanent magnet synchronous generators, MPPT control and a hydrogen gas electrolyzer system. The MPPT controller based on fuzzy logic is designed to adjust the duty ratio of the boost DC-DC converters to absorb maximum power. The proposed fuzzy logic controller assimilates, with (PSF MPPT algorithm which generally used to absorb maximum power from paralleled wind turbines and stores it in form of hydrogen gas. The system is modeled and its behavior is studied using the MATLAB software.

  7. On the injectability of free-standing magnetic nanofilms.

    Science.gov (United States)

    Taccola, Silvia; Pensabene, Virginia; Fujie, Toshinori; Takeoka, Shinji; Pugno, Nicola M; Mattoli, Virgilio

    2017-09-01

    Free-standing films with sub-micrometric thickness, composed of soft polymers and functional nanostructures are promising candidates for many potential applications in the biomedical field, such as reduced port abdominal surgery. In this work, freely suspended poly(L-lactic acid) nanofilms with controlled morphology embedding superparamagnetic iron oxide nanoparticles were fabricated by spin-coating deposition. The mechanical properties of magnetic nanofilms were investigated by Strain-Induced Elastic Buckling Instability for Mechanical Measurements (SIEBIMM) test. Our results show that these freely suspended nanocomposite nanofilms are highly flexible and deformable, with Young's moduli of few GPa. Since they can be handled in liquid with syringes, a quantitative description of the nanofilms behavior during the manipulation with clinically applicable needles has been also provided. These magnetic nanofilms, remotely controllable by external electromagnetic fields, have potential applications in minimally invasive surgery as injectable nanopatches on inner organs wall. Graphical abstract ᅟ.

  8. Polymer-Based Self-Standing Flexible Strain Sensor

    Directory of Open Access Journals (Sweden)

    Fernando Martinez

    2010-01-01

    Full Text Available The design and characterization of polymer-based self-standing flexible strain sensors are presented in this work. Properties as lightness and flexibility make them suitable for the measurement of strain in applications related with wearable electronics such as robotics or rehabilitation devices. Several sensors have been fabricated to analyze the influence of size and electrical conductivity on their behavior. Elongation and applied charge were precisely controlled in order to measure different parameters as electrical resistance, gauge factor (GF, hysteresis, and repeatability. The results clearly show the influence of size and electrical conductivity on the gauge factor, but it is also important to point out the necessity of controlling the hysteresis and repeatability of the response for precision-demanding applications.

  9. Kinetic asymmetry in transfemoral amputees while performing sit to stand and stand to sit movements.

    Science.gov (United States)

    Highsmith, M Jason; Kahle, Jason T; Carey, Stephanie L; Lura, Derek J; Dubey, Rajiv V; Csavina, Kristine R; Quillen, William S

    2011-05-01

    Transitional movements are a determinant of functional independence and have limited study in amputees. Microprocessor prosthetic knees' abilities to assist transfemoral amputees with sitting and standing have not been studied. Through cross-sectional study, 21 transfemoral amputees, divided into 3 groups of 7 by knee type (power knee, C-leg, Mauch SNS) and 7 non-amputee controls (n=28) performed sit to stand and stand to sit while kinematic and kinetic data were recorded. Transfemoral amputees can stand (1.6-2.0s) and sit (2.1-2.8s) at rates comparable to controls (1.6s). Controls' ground reaction force (GRF) and knee moment production was knee moments. For stand to sit, amputees' asymmetry for GRF ranged from 32 to 60% and 84 to 114% for knee moments. Hip moment asymmetry for sit to stand was less for control (21%) and power knee (34%) groups than that produced by the Mauch SNS (59%) group. For stand to sit, hip moment production for the Mauch SNS (47%) and C-leg groups (71%) were more asymmetric than controls (19%). In the majority of cases transfemoral amputees do not load their prosthesis extensively for standing up or sitting down. Therefore, this transitional movement is currently a one-legged task, which increases stress on the sound limb. Generally, the prosthetic knees studied did not produce a significant knee moment in either task. Although most differences between knee groups were not statistically significant, differences may be clinically meaningful on an individual basis. Published by Elsevier B.V.

  10. The effects of obesity and standing time on postural sway during prolonged quiet standing.

    Science.gov (United States)

    Singh, D; Park, W; Levy, M S; Jung, Eui S

    2009-08-01

    This study examined the effects of obesity level, standing time and their interaction on postural sway during a prolonged quiet upright standing task. Ten extremely obese (BMI > 40 kg/m(2)) and 10 non-obese (18.5 kg/m(2) falls, especially during prolonged physical work activities. The research findings are relevant to identifying and reducing risks of balance loss and falls in various workplace settings for a wide variety of workers.

  11. High-speed PIV applied to the wake of the NASA CRM model in ETW at high Re-number stall conditions for sub- and transonic speeds

    OpenAIRE

    Konrath, Robert; Geisler, Reinhard; Otter, Dirk; Philipp, Florian; Ehlers, Hauke; Agocs, Janos; Quest, Jürgen

    2015-01-01

    Within the framework of the EU project ESWIRP the Particle Image Velocimetry (PIV) using high-speed camera and laser has been used to measure the turbulent flow in the wake of a stalled aircraft wing. The measurements took place on the Common Research Model (CRM) provided by NASA in the pressurized cryogenic European Transonic Wind tunnel (ETW). A specific cryo-PIV system has been used and adapted for using high-speed PIV components under the cryogenic conditions of the wind tunnel faci...

  12. Orchestral Stalls, Honore Daumier

    Science.gov (United States)

    Lucero-Criswell, Amber

    2004-01-01

    Honore Daumier is probably best known as a politically motivated artist. Born in Marseilles in 1808, the French artist lived through one of the most turbulent eras of his country's history. With his artistic prowess and biting wit, he recorded the 1848 revolution, the rise and fall of the Second Empire, the Crimean and Franco-Prussian Wars, and…

  13. Sickness behavior in dairy cows during Escherichia coli mastitis

    DEFF Research Database (Denmark)

    Fogsgaard, Katrine Kop; Røntved, Christine Maria; Sørensen, Peter

    2012-01-01

    -recorded on 5 consecutive days, d −2 to +2 after challenge when the cows were not disturbed by humans. The behavior of the animals was compared among all days. Infection with E. coli altered the behavior of the dairy cows. Time spent feeding was lower in the initial 24 h after infection compared......The consequences of mastitis in terms of dairy cow behavior are relatively unknown. Future assessment of dairy cow welfare during mastitis will be facilitated by knowledge about the potential of mastitis to induce sickness behavior. Our aim was to examine behavior of dairy cows in the period from 2...... d before (d −2 and −1) to 3 d (d 0, 1, and 2) after experimental intramammary challenge with Escherichia coli. Effects of experimentally induced mastitis on behavior were examined in 20 primiparous Danish Holstein-Friesian cows, all 3 to 6 wk after calving and kept in tie stalls. After evening...

  14. Modeling natural regeneration biomass of Pinus stand

    Directory of Open Access Journals (Sweden)

    Rafael Cubas

    2016-09-01

    Full Text Available Reliable biomass data are very important in the evaluation of ecosystems, and help in understanding the contribution of forests in climate change. Variables that describe the size of the tree, like diameter and height are directly associated with biomass, which allows the use of regression models to estimate this element. Therefore, this study aimed to estimate by regression models, the biomass of different compartments of natural regeneration of trees of a Pinus taeda L. stand. The data were obtained through direct destructive method, using 100 randomly selected trees in the understory of a stand of Pinus taeda. We analyzed three arithmetical models, three logarithmic and two models developed by Stepwise process. Logarithmic equations developed by Stepwise procedure showed the best estimates of total and stems biomass. However, for needles and twigs compartments the best adjust was observed with Husch model and for root biomass Berkhout model proved to be the most suitable.

  15. 2015 Dust Risk Standing Review Panel

    Science.gov (United States)

    Steinberg, Susan

    2015-01-01

    The 2015 Dust Risk Standing Review Panel (SRP) participated in a WebEx/teleconference with members of the Space Human Factors and Habitability (SHFH) Element, representatives from the Human Research Program (HRP), NASA Headquarters, and the NASA Research Education and Support Services on November 12, 2015. The SRP reviewed the updated Evidence Report for The Risk of Adverse Health and Performance Effects of Celestial Dust Exposure, as well as the Research Plan for this Risk.

  16. Radiological Features of Long-Standing Hypoparathyroidism

    International Nuclear Information System (INIS)

    John, Deepa Regina; Suthar, Pokhraj P.

    2016-01-01

    Idiopathic hypoparathyroidism is an extremely rare endocrinal disorder with a prevalence of 37 per 100,000. Herein we presented a case of a 30-year-old male who came with symptoms of muscle weakness, carpopedal spasms and limitation of movement which gradually progressed over 8 years. A 30-year-old male patient presented in an outpatient department of a tertiary care centre with a complaint of severe pain in both hip joints. He had generalized muscle weakness, facial discomfort, recurrent episodes of carpopedal spasms and crampy abdominal pains. On clinical examination, the patient had Chvostek sign and Trousseau sign. Biochemical tests revealed hypocalcemia, hyperphosphatemia and hypomagnesemia with low plasma parathyroid hormone level. X-ray of the pelvis and spine revealed spondylarthropathic changes of long-standing hypoparathyroidism. Computed Tomography of the brain revealed bilateral basal ganglia calcifications. The patient was treated with intravenous calcium gluconate, magnesium and oral vitamin D3. On follow-up the patient showed improvement of muscle weakness and carpopedal spasm with near-normal biochemical parameters. However, there was no improvement in symptoms related to spondyloarthropathy. Idiopathic hypoparathyroidism is a rare endocrine disorder with clinic and biochemical features of hypocalcemia. Long- standing hypoparathyroidism can cause spondyloarthropathic changes closely resembling ankylosing spondylitis and DISH. Skeletal changes of long-standing hypoparathyroidism are irreversible. If left untreated, life-threatening complications like cardiac arrhythmias and broncholaryngospasm may occur

  17. MICROSCALE METROLOGY USING STANDING WAVE PROBES

    Energy Technology Data Exchange (ETDEWEB)

    Bauza, M B; Woody, S C; Smith, S T; Seugling, R M; Darnell, I; Florando, J N

    2008-08-04

    Miniaturization has been one of the driving forces in the development of new technologies leading to new products in a variety of industries. As a result, the integration of components over several orders of magnitude on the length scale poses enormous challenges for quality assurance and control. Therefore, new solutions are necessary to meet the growing need for more challenging metrology tasks and metrology requirements in nano- and micro-technology. However, with miniaturization, new challenges arise such as the increased influence of adhesion, electrostatic, Van der Waals and meniscus forces that affect the measurement process. Technical solutions to overcome these micro- and nano-metrology challenges will include the need for traceability, new calibration procedures and calibration artifacts. Over the past decade many new metrology tools have been proposed, however; for contact based measurements, adhesion between the measurement probe and the specimen still proves to be one of the more difficult challenges to overcome. To address this issue, a new class of tactile sensing probe referred to as standing wave sensor has been developed and was previously presented. Previous work introduced the principle of operation of the standing wave senor. This work presents new measurements showing applications of the standing wave probe as the sensing element in a microscale high aspect ratio profiling system.

  18. Cross-sectional Examination of Long-term Access to Sit-Stand Desks in a Professional Office Setting.

    Science.gov (United States)

    Carr, Lucas J; Swift, Maggie; Ferrer, Alex; Benzo, Roberto

    2016-01-01

    Prolonged sedentary behavior is an independent risk factor for many negative health outcomes. Although many employers have begun introducing sit-stand desks as means of reducing employee's occupational sitting time, few studies have examined the impact of prolonged access to such desks on sitting/standing time or cardiometabolic outcomes. The present study compared occupational sedentary/physical activity behaviors and cardiometabolic biomarkers among employees with long-term access to traditional sitting and sit-stand desks. This study used a naturalistic, cross-sectional study design. Occupational sedentary and physical activity behaviors and cardiometabolic health outcomes were collected in a controlled laboratory between February and June 2014. Data were analyzed in September 2014. Adults working in full-time sedentary desk jobs who reported having either a sit-stand desk (n=31) or standard sitting desk (n=38) for a minimum of 6 months were recruited. Employees with sit-stand desks sat less (p=0.02) and stood more at work (p=0.01) compared with employees with sitting desks. Significant inverse correlations were observed between several occupational physical activity outcomes (walking time, steps at work) and cardiometabolic risk factors (systolic blood pressure, weight, lean mass, BMI) over the entire sample. Employees with long-term access to sit-stand desks sat less and stood more compared with employees with sitting desks. These findings hold public health significance, as sit-stand desks represent a potentially sustainable approach for reducing sedentary behavior among the large, growing number of sedentary workers at increased risk for sedentariness-related pathologies. Copyright © 2016 American Journal of Preventive Medicine. Published by Elsevier Inc. All rights reserved.

  19. Stand structure and regeneration of harvested Araucaria araucana ...

    African Journals Online (AJOL)

    Stand structure and regeneration of harvested Araucaria araucana–Nothofagus stands in central Chile. Rafael M Navarro-Cerrillo, Fernando Olave, Francisco Moreno, Sergio de Miguel, Margarita Clemente ...

  20. Forest evaporation models: Relationships between stand growth and evaporation

    CSIR Research Space (South Africa)

    Le Maitre, David C

    1997-06-01

    Full Text Available The relationships between forest stand structure, growth and evaporation were analysed to determine whether forest evaporation can be estimated from stand growth data. This approach permits rapid assessment of the potential impacts of afforestation...

  1. Dairy cow preferences for soft or hard flooring when standing or walking.

    Science.gov (United States)

    Telezhenko, E; Lidfors, L; Bergsten, C

    2007-08-01

    Concrete is the most commonly used alley flooring in confined dairy herds because of its qualities of construction and ease of cleaning. Nevertheless, the hardness, abrasiveness, and slipperiness of concrete floors have adverse effects on animal well-being and health, and yielding rubber flooring is becoming popular as a way of improving the flooring conditions on walkways. The aim of this study was to investigate preferences of dairy cows for rubber compared with concrete flooring under the conditions of a commercial dairy farm. The study was conducted in an organic dairy herd with free-stall housing. Floor preference was tested on groups of standing cows in a 120-m2 holding pen before milking, and 1 yr later on a 12- x 3-m walkway. The holding pen and the walkway were divided lengthwise into 2 identical sections. Two types of solid rubber mats (soft and extra soft) were tested against solid concrete in the holding pen. Slatted and solid rubber mats were tested against slatted concrete in the walkway. Each floor type was tested over 4 d on the left side and 4 d on the right side of the holding pen and the walkway, respectively. Concrete flooring on both sides of the sections was tested as a control before the testing of different section materials. All observations of the distribution of cows in the sections were made from video recordings captured in association with the afternoon milking. The number of cows on each section was recorded approximately every 7 min in the holding pen, and continuously on the walkway. A significantly higher proportion of cows stood on the side with the soft and extra soft rubber mats (65.1 +/- 2.7 and 69.3 +/- 2.6%, respectively, mean +/- SEM) compared with the control distribution when only the solid concrete was available (50.9 +/- 3.9%). A significantly higher proportion of nonlame cows walked exclusively on the side with the slatted (64.5 +/- 5.4%, d 4) or solid rubber mats (68.2 +/- 5.1%, d 4) compared with controls (28.9 +/- 4

  2. Avaliação de diferentes materiais para recobrimento de camas em baias de galpão modelo free-stall

    Directory of Open Access Journals (Sweden)

    Daiane Cecchin

    2014-01-01

    Full Text Available Objetivou-se, com o presente trabalho, comparar o uso de cama de colchão de borracha e de areia no recobrimento da superfície de baias para confinamento tipo free-stall. Foram monitoradas 18 vacas holandesas confinadas em galpão modelo free-stall cujas baias foram recobertas com camas de areia e colchão de borracha (tratamentos. O delineamento experimental foi em blocos casualizados. Os parâmetros comportamentais estudados foram os tempos despendidos nas atividades: deitada em ócio e deitada ruminando, em pé em ócio sobre a cama, em pé ruminando sobre a cama, registrados a cada 10 min. As variáveis ambientais e temperatura da superfície das camas foram registradas a cada hora. Houve maior preferência dos animais pela cama de areia para os comportamentos deitada em ócio e deitada ruminando. As vacas permaneceram mais tempo deitadas em cama de borracha somente nos períodos mais frescos (noite e madrugada, devido à temperatura da cama. A temperatura da borracha foi maior que areia nos horários mais quentes do dia (notadamente durante o período da tarde, enquanto à noite se apresentou mais fria.

  3. 21 CFR 880.2700 - Stand-on patient scale.

    Science.gov (United States)

    2010-04-01

    ... 21 Food and Drugs 8 2010-04-01 2010-04-01 false Stand-on patient scale. 880.2700 Section 880.2700... Devices § 880.2700 Stand-on patient scale. (a) Identification. A stand-on patient scale is a device intended for medical purposes that is used to weigh a patient who is able to stand on the scale platform...

  4. The Frontline of Refusal: Indigenous Women Warriors of Standing Rock

    Science.gov (United States)

    Lane, Temryss MacLean

    2018-01-01

    Indigenous women stand in solidarity on the frontline of refusal, protecting their ancestral homelands and their ways of life across North America and beyond. The Indigenous stand-off at Standing Rock in opposition to the Dakota Access Pipeline inspires this photo series of vignettes where Indigenous voices accompany images of Indigenous women in…

  5. Standing Sound Waves in Air with DataStudio

    Science.gov (United States)

    Kraftmakher, Yaakov

    2010-01-01

    Two experiments related to standing sound waves in air are adapted for using the ScienceWorkshop data-acquisition system with the DataStudio software from PASCO scientific. First, the standing waves are created by reflection from a plane reflector. The distribution of the sound pressure along the standing wave is measured. Second, the resonance…

  6. Relationship of stand age to streamwater nitrate in New Hampshire

    Science.gov (United States)

    William B. Leak; C. Wayne Martin

    1975-01-01

    Streamwater nitrate content of six watersheds during spring and summer was apparently related to stand age or age since disturbance. Nitrate concentration averaged 10.3 ppm right after cutting, dropped to a trace in medium-aged stands, and then rose again to a maximum of 4.8 ppm as stands became overmature.

  7. Standing dead tree resources in forests of the United States

    Science.gov (United States)

    Christopher W. Woodall; Karen L. Waddell; Christopher M. Oswalt; James E. Smith

    2013-01-01

    Given the importance of standing dead trees to numerous forest ecosystem attributes/ processes such as fuel loadings and wildlife habitat, the Forest Inventory and Analysis (FIA) Program of the Forest Service, U.S. Department of Agriculture, initiated a consistent nationwide inventory of standing dead trees in 1999. As the first cycle of annual standing dead tree...

  8. The zero inflation of standing dead tree carbon stocks

    Science.gov (United States)

    Christopher W. Woodall; David W. MacFarlane

    2012-01-01

    Given the importance of standing dead trees in numerous forest ecosystem attributes/processes such as carbon (C) stocks, the USDA Forest Service’s Forest Inventory and Analysis (FIA) program began consistent nationwide sampling of standing dead trees in 1999. Modeled estimates of standing dead tree C stocks are currently used as the official C stock estimates for the...

  9. STUDY ON THE EXPLAINABLE ABILITY BY USING AIRBORNE LIDAR IN STAND VALUE AND STAND COMPETITION

    Directory of Open Access Journals (Sweden)

    S. C. Huang

    2016-06-01

    Full Text Available Forest canopy structure is composed by the various species. Sun light is a main factor to affect the crown structures after tree competition. However, thinning operation is an appropriate way to control canopy density, which can adjust the competition conditions in the different crown structures. Recently, Airborne Light Detection and Ranging (LiDAR, has been established as a standard technology for high precision three dimensional forest data acquisition; it could get stand characteristics with three-dimensional information that had develop potential for the structure characteristics of forest canopy. The 65 years old, different planting density of Cryptomeria japonica experiment area was selected for this study in Nanytou, Taiwan. Use the LiDAR image to estimate LiDAR characteristic values by constructed CHM, voxel-based LiDAR, mu0ltiple echoes, and assess the accuracy of stand characteristics with intensity values and field data. The competition index was calculated with field data, and estimate competition index of LiDAR via multiple linear regression. The results showed that the highest accuracy with stand characteristics was stand high which estimate by LiDAR, its average accuracy of 91.03%. LiDAR raster grid size was 20 m × 20 m for the correlation was the best, however, the higher canopy density will reduce the accuracy of the LiDAR characteristic values to estimate the stand characteristics. The significantly affect canopy thickness and the degree of competition in different planting distances.

  10. Investigation of Unsteady Flow Behavior in Transonic Compressor Rotors with LES and PIV Measurements

    Science.gov (United States)

    Hah, Chunill; Voges, Melanie; Mueller, Martin; Schiffer, Heinz-Peter

    2009-01-01

    In the present study, unsteady flow behavior in a modern transonic axial compressor rotor is studied in detail with large eddy simulation (LES) and particle image velocimetry (PIV). The main purpose of the study is to advance the current understanding of the flow field near the blade tip in an axial transonic compressor rotor near the stall and peak-efficiency conditions. Flow interaction between the tip leakage vortex and the passage shock is inherently unsteady in a transonic compressor. Casing-mounted unsteady pressure transducers have been widely applied to investigate steady and unsteady flow behavior near the casing. Although many aspects of flow have been revealed, flow structures below the casing cannot be studied with casing-mounted pressure transducers. In the present study, unsteady velocity fields are measured with a PIV system and the measured unsteady flow fields are compared with LES simulations. The currently applied PIV measurements indicate that the flow near the tip region is not steady even at the design condition. This self-induced unsteadiness increases significantly as the compressor rotor operates near the stall condition. Measured data from PIV show that the tip clearance vortex oscillates substantially near stall. The calculated unsteady characteristics of the flow from LES agree well with the PIV measurements. Calculated unsteady flow fields show that the formation of the tip clearance vortex is intermittent and the concept of vortex breakdown from steady flow analysis does not seem to apply in the current flow field. Fluid with low momentum near the pressure side of the blade close to the leading edge periodically spills over into the adjacent blade passage. The present study indicates that stall inception is heavily dependent on unsteady behavior of the flow field near the leading edge of the blade tip section for the present transonic compressor rotor.

  11. Stand-alone photovoltaic applications. Lessons learned

    International Nuclear Information System (INIS)

    Loois, G.; Van Hemert, B.

    1999-02-01

    The IEA Photovoltaic Power Systems Programme (PVPS) is one of the collaborative R and D agreements established within the IEA. The objective of Task III is to promote and facilitate the exchange of information and experiences in the field of PV Systems in Stand-alone and Island Applications (SAPV). The book focuses on the practical experiences gained, and does not aim to provide a complete manual on SAPV. When Task III started its activities in 1993, a collection of 50 'State of the art' projects was published in the book 'Examples of Stand-Alone Photovoltaic Systems'. This publication marked the base line for the work of the task. Now, in 1998, the showcases from each country demonstrate the lessons learned in five years of cooperation. The book consists of two parts. The first part contains eight chapters dealing with a specific aspect of stand-alone PV. The second part introduces 14 national showcase projects in a systematic presentation. Each chapter and showcase can be read independently from the rest of the book. Chapter 2, contributed by The Netherlands, analyses the market for stand-alone PV systems. It gives an overview of the 'traditional' application of stand-alone PV, which is the electrification of remote buildings and which has been addressed in depth in other publications. The focus is on the market niches of service applications that are also interesting for more densely populated areas, e.g. in industrialised countries. The United Kingdom illustrates the economic aspects in Chapter 3. Cost comparisons are made, but more important is the illustration of the non-financial considerations that make PV the preferred choice as a power source for many applications. Switzerland explores in Chapter 4 (financing aspects) different financing mechanisms, and financial policies used to overcome the initial cost barrier. Most of these approaches have been applied in developing countries rather than in the western world. Using various examples from all over the

  12. Stand development and yields of Appalachian hardwood stands managed with single-tree selection for at least 30 years

    Science.gov (United States)

    Neil I Lamson; H. Clay Smith; H. Clay Smith

    1991-01-01

    Appalachian hardwood stands in West Virginia were managed for 30 or more years using single-tree selection regeneration practices. Stand yield data suggest that current stand growth will provide economical harvest cuts for several future cutting cycles. This case study indicates that the single-tree selection practice has potential for landowners who want to maintain...

  13. Stand quality management in a late-rotation, red oak-sweetgum stand in east Mississippi: preliminary results following thinning

    Science.gov (United States)

    James S. Meadows; Daniel A. Skojac

    2012-01-01

    Stand quality management is a new management strategy in which thinning prescriptions are based solely on tree quality rather than a quantitative level of residual stand density. As long as residual density falls within fairly broad limits, prescriptions are based on tree quality alone. We applied four thinning prescriptions based on stand quality management, along...

  14. Reconstructed old-growth forest stand structure and composition of two stands on the Olympic Peninsula, Washington state

    Science.gov (United States)

    David H. Peter; Constance A. Harrington

    2010-01-01

    We reconstructed the stand structure and composition for two western Washington old-growth forest stands harvested around 1930 (named Fresca and Rail) from field and historical data. Both old-growth stands had a codominant or dominant 250-year-old Douglas-fir (Pseudotsuga menziesii (Mirb.) Franco) overstory with a few scattered older Douglas-fir....

  15. Maintaining standing balance by handrail grasping.

    Science.gov (United States)

    Sarraf, Thiago A; Marigold, Daniel S; Robinovitch, Stephen N

    2014-01-01

    Maintaining balance while standing on a moving bus or subway is challenging, and falls among passengers are a significant source of morbidity. Standing passengers often rely on handrail grasping to resist perturbations to balance. We conducted experiments that simulated vehicle starts, to examine how handrail location (overhead or shoulder-height), perturbation direction (forward, backward, left or right), and perturbation magnitude (1 or 2m/s(2)) affected the biomechanical effort (peak centre-of-pressure (COP) excursion and hand force) and muscle activations (onset and integrated EMG activity) involved in balance maintenance. COP excursions, hand forces and muscle activations were altered in a functional manner based on task constraints and perturbation characteristics. Handrail position affected normalized values of peak COP and hand force during forward and backward, but not sideways perturbations. During backward perturbations, COP excursion was greater when grasping overhead than shoulder-height. During forward perturbations, hand force was greater when grasping shoulder-height than overhead. Biceps activations were earlier during shoulder-height than overhead grasping, while tibialis anterior activity was higher during overhead than shoulder-height grasping. Our results indicate that, when facing forward or backward to the direction of vehicle motion, overhead grasping minimizes hand force, while shoulder-height grasping minimizes COP excursion. In contrast, grasping with a sideways stance eliminates the effect of handrail location, and was associated with equal or lower biomechanical effort. This suggests that, at least for vehicle starts, the most reasonable strategy may be to stand sideways to the direction of the vehicle movement, and grasp either at shoulder-height or overhead. Copyright © 2013 Elsevier B.V. All rights reserved.

  16. Long-standing poliomyelitis and psychological health.

    Science.gov (United States)

    Shiri, Shimon; Gartsman, Irina; Meiner, Zeev; Schwartz, Isabella

    2015-01-01

    To compare the psychological health of the individuals with long-standing poliomyelitis, with or without post-polio syndrome (PPS), to the general population and to identify the role of work as well as other variables with regard to their psychological health. A cross-sectional study. One hundred and ninety-five polio patients attending postpolio clinic in Jerusalem. Emotional distress (ED) was measured using the general health questionnaire (GHQ-12). Demographic, medical, social and functional data were recorded using a specific structured questionnaire. Each polio patient was compared to four age- and sex-matched controls. ED was higher in the polio population as compared to the general population. Within the polio population ED was inversely correlated with work status. No correlation was found between ED and the functional level of polio participants and no difference was found in GHQ score between polio participants with or without post-polio. In addition, ED was less affected by subjective perception of physical health among polio patients as compared to the general population. Long-standing poliomyelitis is associated with decreased psychological health as compared to the general population. Yet, the resilience of polio survivors is manifested by their ability to block further decline of their psychological health in spite of deterioration in their physical health. Work appears as a significant source of resilience in the polio population. Implications for Rehabilitation Individuals with long-standing poliomyelitis often suffer from high emotional distress and may benefit from psychotherapy aimed at reducing distress. As active employment status is associated with increased mental health among polio survivors, encouraging participation at work needs to be a significant component of psychotherapeutic programs. Polio survivors, although physically disabled, may be relatively resilient, as their mental health is less affected by their negative health perception

  17. Construction of an automated table standing

    Science.gov (United States)

    Neira, R. E.; Barbero, M. D.; Di Giulio, E. A.; Folco, J. F.; Jiménez, G. F.

    2011-12-01

    In this paper, the construction of an upright stretcher designed for patients in rehabilitation. The standing back to patients' expectations of therapeutic improvement, allowing correct all the troubles of a passive long. It has been shown that this table favors not only physically but also has a psychological reach beyond the scope of physical therapy and strongly affects the recovery. At the same time, the use of an upright stretcher greatly decreases the biomechanical disorders of hospital staff in the process of recovery. Thus the problem of rehabilitation of trafficking in a comprehensive way which not only focuses on the patient's undivided attention but also includes medical and auxiliary personnel.

  18. Final Focus Test Stand final report

    CERN Document Server

    Jeremie, A; Burrows, P

    2013-01-01

    Future Linear colliders will need particle beam sizes in the nanometre range. The beam also needs to be stable all along the beam line and especially at the Final Focus section. A dedicated Final Focus test stand has been used for this study and is comprised of several sub-parts. First there is the Stabilisation/Isolation system with sensors and actuators stabilizing down to sub-nanometre level. Then the Magnet itself needs to comply with very specific design constraints. In addition to the mechanical items, the beam can be stabilized acting on the trajectory directly and Beam-based controls have been developed and tested on different accelerator facilities.

  19. Construction of an automated table standing

    International Nuclear Information System (INIS)

    Neira, R E; Barbero, M D; Di Giulio, E A; Folco, J F; Jiménez, G F

    2011-01-01

    In this paper, the construction of an upright stretcher designed for patients in rehabilitation. The standing back to patients' expectations of therapeutic improvement, allowing correct all the troubles of a passive long. It has been shown that this table favors not only physically but also has a psychological reach beyond the scope of physical therapy and strongly affects the recovery. At the same time, the use of an upright stretcher greatly decreases the biomechanical disorders of hospital staff in the process of recovery. Thus the problem of rehabilitation of trafficking in a comprehensive way which not only focuses on the patient's undivided attention but also includes medical and auxiliary personnel.

  20. Residual liquefaction of seabed under standing waves

    DEFF Research Database (Denmark)

    Kirca, V.S. Ozgur; Sumer, B. Mutlu; Fredsøe, Jørgen

    2013-01-01

    This paper presents the results of an experimental study of the seabed liquefaction beneath standing waves. Silt (with d50 =0.070mm) was used in the experiments. Two kinds of measurements were carried out: pore water pressure measurements and water surface elevation measurements. These measurements...... qualitatively similar, show features different from that caused by progressive waves. The pore water pressure builds up (or accumulated) in the areas around the node and subsequently spreads out toward the antinodes. The experimental results imply that this transport is caused by a diffusion mechanism...

  1. Methods for evaluating crown area profiles of forest stands

    Science.gov (United States)

    Dubrasich, Michael E.; Hann, D.W.; Tappeiner, J. C.

    1997-01-01

    Canopy architectures of five structurally complex forest stands and three structurally simple forest stands in southwest Oregon and the Willamette Valley, Oregon, were evaluated and quantified through crown area profiles. Mixed conifer and mixed conifer hardwood stands across a range of sites were sampled for crown widths and heights. Crown width and shape equations were derived and used to quantify the stand crown area at incremental heights above the forest floor. Crown area profiles describe the spatial arrangement of aboveground forest vegetation and the total pore spaces between crowns. Plot by plot profiles were combined to produce vertical and horizontal displays of the stand crown area distribution. In complex stands, the forest space was moderately occupied by crowns from the forest floor up to heights over 30 m, producing uniform distributions of between-crown porosity. The structurally complex stands had between-crown porosity values of 70% to 90% for more than 23 vertical metres of canopy, and they had total between-crown porosities of 86% to 91%. The structurally simple stands had between-crown porosity values of 70% to 90% for less than 8 vertical metres of canopy, and they had total between-crown porosities of 69% to 85%. Variances in crown area indicate that variation in horizontal crown area (within heights) was larger in complex stands than in simple stands, but vertical crown areas (between heights) varied less in complex stands. The study provides a basis for discriminating between canopy architectures and for quantifying the porosity of forest canopies.

  2. Science stand-up at CERN

    CERN Multimedia

    Stephanie McClellan

    2013-01-01

    Supported by host Helen Keen from BBC4’s "It is Rocket Science", six amateur performers from CERN (Sam Gregson, Alex Brown, Benjamin Frisch, Claire Lee, Hugo Day and Clara Nellist) were joined on stage by geek-pop sensation Jonny Berliner and comedians Pierre Novellie and Lieven Scheire for a night of science stand-up comedy.   Host Helen Keen starts off the comedy event. (Image: Piotr Traczyk). Like the genesis of most great things, the LHComedy event began as an idea. Sam Gregson, a PhD student at CERN, had been a regular at the Cambridge Bright Club. This public engagement event promotes scientists’ research through stand-up comedy. Sam thought, “If people came to watch Bright Club at Cambridge and enjoyed the research, why can’t we do it at the biggest scientific experiment in the world?” Sam’s idea gained momentum after being introduced to FameLab participants at CERN. Similar to Bright Club, FameLab is a com...

  3. Effect of timing of relocation of replacement gilts from group pens to individual stalls before breeding on fertility and well-being.

    Science.gov (United States)

    Knox, R V; Shen, J; Greiner, L L; Connor, J F

    2016-12-01

    Variation in gilt fertility is associated with increased replacement and reduced longevity. Stress before breeding is hypothesized to be involved in reduced fertility. This study tested the timing of gilt relocation from pens to individual stalls before breeding on fertility and well-being. The experiment was performed in replicates on a commercial research farm. After detection of first estrus, gilts ( = 563) were assigned to treatment for relocation into stalls 3 wk (REL3wk), 2 wk (REL2wk), or 1 wk (REL1wk) before breeding at second estrus. Subsets of gilts from each treatment ( = 60) were selected for assessment of follicles at second estrus. Data included interestrus interval, number of services, conception, farrowing, total born, and wean to service interval. Piglet birth weight was obtained on subsets of litters ( = 42/treatment). Measures of well-being included BW, backfat, BCS, lesions, and lameness from wk 1 after first estrus until wk 16. Gilt BW at wk 5 (158.4 kg) was not affected ( > 0.10) by treatment. Measures of BCS, lameness, and lesions at breeding and throughout gestation did not differ ( > 0.10). Treatment did not affect ( > 0.10) gilts expressing a normal interestrus interval of 18 to 24 d (83.4%) but did influence ( Gilts in REL3wk had a shorter ( Gilts with shorter intervals ( = 24) had fewer total born while gilts expressing longer cycles ( = 65) had reduced farrowing rates. The number of services (1.9) and number of follicles (19.7) at breeding were not affected ( > 0.10) by relocation. There was no effect of treatment on farrowing rate (85.2%), born alive (12.6), or any litter birth weight measures ( > 0.10). The percentage of sows bred within 7 d after weaning (94.4%) was also not affected by treatment ( > 0.10). These results suggest that the timing of relocation before breeding had no effect on well-being or on the majority of gilts with normal estrous cycles and their subsequent fertility. However, a smaller proportion of the gilts

  4. Phenotypes of dnaXE145A Mutant Cells Indicate that the Escherichia coli Clamp Loader Has a Role in the Restart of Stalled Replication Forks.

    Science.gov (United States)

    Flåtten, Ingvild; Helgesen, Emily; Pedersen, Ida Benedikte; Waldminghaus, Torsten; Rothe, Christiane; Taipale, Riikka; Johnsen, Line; Skarstad, Kirsten

    2017-12-15

    The Escherichia coli dnaX E145A mutation was discovered in connection with a screen for multicopy suppressors of the temperature-sensitive topoisomerase IV mutation parE10 The gene for the clamp loader subunits τ and γ, dnaX , but not the mutant dnaX E145A , was found to suppress parE10 (Ts) when overexpressed. Purified mutant protein was found to be functional in vitro , and few phenotypes were found in vivo apart from problems with partitioning of DNA in rich medium. We show here that a large number of the replication forks that initiate at oriC never reach the terminus in dnaX E145A mutant cells. The SOS response was found to be induced, and a combination of the dnaX E145A mutation with recBC and recA mutations led to reduced viability. The mutant cells exhibited extensive chromosome fragmentation and degradation upon inactivation of recBC and recA , respectively. The results indicate that the dnaX E145A mutant cells suffer from broken replication forks and that these need to be repaired by homologous recombination. We suggest that the dnaX -encoded τ and γ subunits of the clamp loader, or the clamp loader complex itself, has a role in the restart of stalled replication forks without extensive homologous recombination. IMPORTANCE The E. coli clamp loader complex has a role in coordinating the activity of the replisome at the replication fork and loading β-clamps for lagging-strand synthesis. Replication forks frequently encounter obstacles, such as template lesions, secondary structures, and tightly bound protein complexes, which will lead to fork stalling. Some pathways of fork restart have been characterized, but much is still unknown about the actors and mechanisms involved. We have in this work characterized the dnaX E145A clamp loader mutant. We find that the naturally occurring obstacles encountered by a replication fork are not tackled in a proper way by the mutant clamp loader and suggest a role for the clamp loader in the restart of stalled

  5. Rehabilitation of Understocked Loblolly-Shortleaf Pine Stands - I. Recently Cutover Natural Stands

    Science.gov (United States)

    James B. Baker; Michael G. Shelton

    1998-01-01

    A 1988 USDA Forest Service report indicated that 22% (40 million ac) of the commercial timberland in the South was understocked (less than 60% stocking) with desirable tree species for timber production (USDA Forest Service 1988). The understocked stands are usually the result of past har-vesting practices, natural catastrophes, or regeneration fail-ures. Understocked...

  6. Transmission components of solar radiation in pine stands in relation to climatic and stand variables

    Science.gov (United States)

    Robert A. Muller

    1971-01-01

    In a new approach, transmission was studied by relating to stand biomass the ratio of incoming solar radiation beneath tree crowns to that within the atmosphere. Several assumptions were used to estimate analytically the various ways in which solar radiation penetrates through crowns of three pine species in northern California. Sunflecks accounted for much of the...

  7. Blood pressure associates with standing balance in elderly outpatients.

    Directory of Open Access Journals (Sweden)

    Jantsje H Pasma

    Full Text Available OBJECTIVES: Assessment of the association of blood pressure measurements in supine and standing position after a postural change, as a proxy for blood pressure regulation, with standing balance in a clinically relevant cohort of elderly, is of special interest as blood pressure may be important to identify patients at risk of having impaired standing balance in routine geriatric assessment. MATERIALS AND METHODS: In a cross-sectional cohort study, 197 community-dwelling elderly referred to a geriatric outpatient clinic of a middle-sized teaching hospital were included. Blood pressure was measured intermittently (n = 197 and continuously (subsample, n = 58 before and after a controlled postural change from supine to standing position. The ability to maintain standing balance was assessed during ten seconds of side-by-side, semi-tandem and tandem stance, with both eyes open and eyes closed. Self-reported impaired standing balance and history of falls were recorded by questionnaires. Logistic regression analyses were used to examine the association between blood pressure and 1 the ability to maintain standing balance; 2 self-reported impaired standing balance; and 3 history of falls, adjusted for age and sex. RESULTS: Blood pressure decrease after postural change, measured continuously, was associated with reduced ability to maintain standing balance in semi-tandem stance with eyes closed and with increased self-reported impaired standing balance and falls. Presence of orthostatic hypotension was associated with reduced ability to maintain standing balance in semi-tandem stance with eyes closed for both intermittent and continuous measurements and with increased self-reported impaired standing balance for continuous measurements. CONCLUSION: Continuous blood pressure measurements are of additional value to identify patients at risk of having impaired standing balance and may therefore be useful in routine geriatric care.

  8. Experimental studies of flow separation and stalling on two-dimensional airfoils at low speeds. Phase 2: Studies with Fowler flap extended

    Science.gov (United States)

    Seetharam, H. C.; Wentz, W. H., Jr.

    1975-01-01

    Results were given on experimental studies of flow separation and stalling on a two-dimensional GA(W)-1 17 percent thick airfoil with an extended Fowler flap. Experimental velocity profiles obtained from a five tube probe survey with optimum flap gap and overlap setting (flap at 40 deg) are shown at various stations above, below, and behind the airfoil/flap combination for various angles of attack. The typical zones of steady flow, intermittent turbulence, and large scale turbulence were obtained from a hot wire anemometer survey and are depicted graphically for an angle of attack of 12.5 deg. Local skin friction distributions were obtained and are given for various angles of attack. Computer plots of the boundary layer profiles are shown for the case of the flap at 40 deg. Static pressure contours are also given. A GA(W)-2 section model was fabricated with 30 percent Fowler flaps and with pressure tabs.

  9. Physiological and behavioral responses of Nellore steers to artificial shading in an intensive production system

    Directory of Open Access Journals (Sweden)

    Diogo Alves da Costa Ferro

    2016-09-01

    Full Text Available The influence of artificial shading on environmental variables and on behavioral responses of Nellore steers in an intensive production system was evaluated in this study. The experiment was conducted in the experimental feedlot of the Department of Animal Science at Universidade Estadual de Goiás, from July to October 2014. Forty-eight male Nellore cattle with an average initial weight of 310 kg were kept in double 24-m2 stalls, in a total of 24 stalls. Of these, six were in the open air; six were covered with black shade netting of 30% light interception; six with black shade netting 50%; and six with black shade netting 80%, providing 6 m2 of shade per stall. Temperature-humidity index (THI and respiratory frequency (RF were assessed twice weekly and behavior was evaluated fortnightly during 12 h, between 06:00 h and 18.00 h. Feeding behavior, rumination, rest, and social activities such as body care and playful and abnormal activities were observed. A significant increase was found in THI and RF as the shading levels decreased, while a significant difference was recorded in rest and in other activities, water intake, and play behavior. Rest time and playful behavior increased significantly, and other activities and water intake decreased with the increase in shading levels. Shading does not change the time spent on feeding behaviors and rumination, or the frequencies of urination, defecation, cleaning other animals, self-cleaning, and social and abnormal types of behavior. The use of black shade netting of 80% light interception provides greater comfort to animals, promoting welfare and quality of life to them.

  10. The efforts of a multidisciplinary approach in the rehabilitation institute for deaf children: A psychosocial intervention aimed at breaking the pattern of stalled productivity

    Directory of Open Access Journals (Sweden)

    Langher Viviana

    2012-01-01

    Full Text Available The multidisciplinary approach for the treatment of hearing impaired children presented the work group with several tasks: the group had to integrate different competences and techniques, to share common treatment goals, to manage relational dynamics with the children and their parents, and to explore the families' expectancies. These efforts may create stressful conditions for the work group and, consequently, might negatively affect the quality of the intervention to be carried out. Our aim was to illustrate a psychosocial analysis performed in a religious Institute for hearing impaired children, intended to break the pattern of the Institute's stalled productivity, to avoid inefficient and fragmented treatments, to prevent unelaborated relational dynamics among the staff members and between the staff and the children's families. By means of the Content Analysis of semi-structured interviews administered to staff-members and families we have analyzed the quality of the teamwork, the relational arrangements towards the families and local services (25 interviews with 5 staff members; the family-Institute relationship and the family's representation and satisfaction of the Institute (7 interviews with 13 hearing impaired parents and non-hearing impaired parents. The institute activity seemed to be more characterized by the maintenance of the relationship with the families per se, rather than oriented to productive goals. The non hearing impaired parents seemed to be more satisfied than the hearing-impaired parents, possibly because the former are more prepared to receive the Institute's help. The stalled productivity can only be overcome by the elaboration of those relational/emotional dynamics which prevent staff members and children's parents from focusing on productive goals. The staffmembers' training should be improved in order to develop specific competences, to perform an integrated, multidisciplinary approach in treatments, to negotiate

  11. STATUS OF X-BAND STANDING WAVE STRUCTURE STUDIES AT SLAC

    International Nuclear Information System (INIS)

    Dolgashev, Valery A.

    2003-01-01

    The linacs proposed for the Next Linear Collider (NLC) and Japanese Linear Collider (JLC) would contain several thousand X-Band accelerator structures that would operate at a loaded gradient of 50 MV/m. An extensive experimental and theoretical program is underway at SLAC, FNAL and KEK to develop structures that reliably operate at this gradient. The development of standing wave structures is a part of this program. The properties of standing wave structures allow them to operate at the loaded gradient in contrast to traveling wave structures that need conditioning to the unloaded gradient (65 MV/m for NLC/JLC). The gradients in the standing structures tested thus far have been limited by input coupler breakdowns. The behavior of these breakdowns is consistent with a model of pulsed heating due to high magnetic fields. New input couplers have been designed to reduce maximum magnetic fields. This paper discusses design considerations related to high power performance, wakefield suppression and results of high power tests of prototype standing wave structures

  12. Standing variation in spatially growing populations

    Science.gov (United States)

    Fusco, Diana; Gralka, Matti; Kayser, Jona; Hallatschek, Oskar

    Patterns of genetic diversity not only reflect the evolutionary history of a species but they can also determine the evolutionary response to environmental change. For instance, the standing genetic diversity of a microbial population can be key to rescue in the face of an antibiotic attack. While genetic diversity is in general shaped by both demography and evolution, very little is understood when both factors matter, as e.g. for biofilms with pronounced spatial organization. Here, we quantitatively explore patterns of genetic diversity by using microbial colonies and well-mixed test tube populations as antipodal model systems with extreme and very little spatial structure, respectively. We find that Eden model simulations and KPZ theory can remarkably reproduce the genetic diversity in microbial colonies obtained via population sequencing. The excellent agreement allows to draw conclusions on the resilience of spatially-organized populations and to uncover new strategies to contain antibiotic resistance.

  13. The stand prototype of minimum power NRE reactor

    International Nuclear Information System (INIS)

    Belogurov, A.I.; Grigorenko, L.N.; Mamontov, Yu.I.; Rachuk, V.S.; Stukalov, A.I.; Konyukhov, G.V.

    1995-01-01

    For ensuring of full-scale development of nuclear rocket engine (NRE) reactor was created stand prototype (reactor IRGIT?) The main differences of its are as follows: 1) Fasteners of technologies channels contents fuel assemblies in bottom are worked out the split. It is provides possibility a distance channels change without disassembly of reactor stand prototype from stand; 2) Cooling of the vessels, the moderator, the reflector and the barrel actuate is carried out by hydrogen; 3) The lower bottom modified for organization the hydrogen efflux in the form a reactor jet; 4) Radiation defence is introduced as part of stand prototype for ensuring of serviceability of stand accessories and tests routine service; 5) Each technology channels is provided of critical nozzle; 6) Control, regulation and defence of reactor has being carried out on stand system

  14. Stand model for upland forests of Southern Arkansas

    Energy Technology Data Exchange (ETDEWEB)

    Mielke, D.L.; Shugart, H.H.; West, D.C.

    1978-06-01

    A forest stand growth and composition simulator (FORAR) was developed by modifying a stand growth model by Shugart and West (1977). FORAR is a functional stand model which used ecological parameters to relate individual tree growth to environment rather than using Markov probability matrices or differential equations to determine single tree or species replacement rates. FORAR simulated tree growth and species composition of upland forests of Union County, Ark., by considering 33 tree species on a /sup 1///sub 12/ ha circular plot.

  15. Biomass expansion factors for Eucalyptus globulus stands in Portugal

    Energy Technology Data Exchange (ETDEWEB)

    Soares, P.; Tome, M.

    2012-11-01

    One of several procedures for estimating carbon stocks in forests is the estimation of tree or stand biomass based on forest inventory data. The two approaches normally used to convert field measurements of trees to stand biomass values are allometric biomass equations and biomass expansion factors (BEFs). BEFs are used in published National Forest Inventory results in which biomass is not estimated or as a complement of growth models that do not include biomass predictions. In this paper, the effectiveness of BEFs for estimating total stand biomass in Portuguese Eucalyptus globulus plantations was analyzed. Here, BEF is defined as the ratio of total stand biomass (aboveground biomass plus root biomass) to stand volume with bark. To calculate total biomass, an equation was developed to estimate root biomass as a function of aboveground biomass. Changes of BEF with stand variables were analyzed. Strong relationships were observed between BEF and stand age, stand basal area, stand volume and dominant height. Consequently, an equation to predict BEF as a function of stand variables was fitted, and dominant height was selected as the predictor stand variable. Estimates of total stand biomass based on individual tree allometric equations were compared with estimates obtained with a constant BEF (0.77), used in the Portuguese National Inventory Report on Greenhouse Gases, and with estimates obtained using the dominant height-dependent BEF equation developed in this work. The BEF prediction model proposed in this work may be used to improve E. globulus Portuguese biomass estimates when tree allometric equations cannot be used. (Author) 40 refs.

  16. Estimation of stand-level leaf area for boreal bryophytes.

    Science.gov (United States)

    Bond-Lamberty, Ben; Gower, Stith T

    2007-04-01

    Bryophytes dominate the carbon and nitrogen cycling of many poorly drained terrestrial ecosystems and are important in the vegetation-atmosphere exchange of carbon and water, yet few studies have estimated their leaf area at the stand scale. This study quantified the bryophyte-specific leaf area (SLA) and leaf area index (LAI) in a group of different-aged boreal forest stands in well and poorly drained soils. Species-specific SLA (for three feather mosses, four Sphagnum spp. and Aulacomnium palustre mixed with Tomentypnum nitens) was assessed by determining the projected area using a flatbed scanner and cross-sectional geometry using a dissecting microscope. The hemisurface leaf area was computed as the product of SLA and live biomass and was scaled by coverage data collected at all stands. Pleurozium schreberi dominated the spatial coverage, biomass and leaf area in the well-drained stands, particularly the oldest, while S. fuscum and A. palustre were important in the poorly drained stands. Live moss biomass ranged from 47 to 230 g m(-2) in the well-drained stands dominated by feather mosses and from 102 to 228 g m(-2) in the poorly drained stands. Bryophyte SLA varied between 135 and 473 cm(2) g(-1), for A. palustre and S. capillifolium, respectively. SLA was strongly and significantly affected by bryophyte species, but did not vary between stands; in general, there was no significant difference between the SLA of non-Sphagnum mosses. Bryophyte LAI increased with stand age, peaking at 3.1 and 3.7 in the well and poorly drained stands, respectively; this represented approximately 40% of the overstory LAI in the well-drained stands and 100-1,000% in the poorly drained stands, underscoring the important role bryophytes play in the water and carbon budgets of these boreal forests.

  17. Wildlife response to stand structure of deciduous woodlands

    Science.gov (United States)

    Robert A. Hodorff; Carolyn Hull Sieg; Raymond L. Linder

    1988-01-01

    Deciduous woodlands provide important habitat for wildlife but comprise Fraxinus pennsylvanica) woodlands in northwestern South Dakota. Closed-canopy stands were multilayered communities with dense...

  18. Flexible integration of free-standing nanowires into silicon photonics.

    Science.gov (United States)

    Chen, Bigeng; Wu, Hao; Xin, Chenguang; Dai, Daoxin; Tong, Limin

    2017-06-14

    Silicon photonics has been developed successfully with a top-down fabrication technique to enable large-scale photonic integrated circuits with high reproducibility, but is limited intrinsically by the material capability for active or nonlinear applications. On the other hand, free-standing nanowires synthesized via a bottom-up growth present great material diversity and structural uniformity, but precisely assembling free-standing nanowires for on-demand photonic functionality remains a great challenge. Here we report hybrid integration of free-standing nanowires into silicon photonics with high flexibility by coupling free-standing nanowires onto target silicon waveguides that are simultaneously used for precise positioning. Coupling efficiency between a free-standing nanowire and a silicon waveguide is up to ~97% in the telecommunication band. A hybrid nonlinear-free-standing nanowires-silicon waveguides Mach-Zehnder interferometer and a racetrack resonator for significantly enhanced optical modulation are experimentally demonstrated, as well as hybrid active-free-standing nanowires-silicon waveguides circuits for light generation. These results suggest an alternative approach to flexible multifunctional on-chip nanophotonic devices.Precisely assembling free-standing nanowires for on-demand photonic functionality remains a challenge. Here, Chen et al. integrate free-standing nanowires into silicon waveguides and show all-optical modulation and light generation on silicon photonic chips.

  19. Tilt table standing for reducing spasticity after spinal cord injury.

    Science.gov (United States)

    Bohannon, R W

    1993-10-01

    A patient with a T12 spinal cord injury and intractable extensor spasms of the lower extremities participated in tilt table standing trial on 5 nonconsecutive days to determine if the intervention would affect his spasticity and spasms. Each day's standing trial was followed by an immediate reduction in lower extremity spasticity (measured using the modified Ashworth scale and pendulum testing). Standing was also accompanied by a reduction in spasms that lasted until the following morning. The reduction of spasms was particularly advantageous to the performance of car transfers. Tilt table standing merits further examination as a physical treatment of spasms that accompany central nervous system lesions.

  20. Aboveground net primary production decline with stand age: potential causes.

    Science.gov (United States)

    Gower, S T; McMurtrie, R E; Murty, D

    1996-09-01

    Aboveground net primary production (ANPP) commonly reaches a maximum in young forest stands and decreases by 0-76% as stands mature. However, the mechanism(s) responsible for the decline are not well understood. Current hypotheses for declining ANPP with stand age include: (1) an altered balance between photosynthetic and respiring tissues, (2) decreasing soil nutrient availability, and (3) increasing stomatal limitation leading to reduced photosynthetic rates. Recent empirical and modeling studies reveal that mechanisms (2) and (3) are largely responsible for age-related decline in ANPP for forests in cold environments. Increasing respiratory costs appear to be relatively unimportant in explaining declining productivity in ageing stands.

  1. Jumping Stand Apparatus Reveals Rapidly Specific Age-Related Cognitive Impairments in Mouse Lemur Primates.

    Directory of Open Access Journals (Sweden)

    Jean-Luc Picq

    Full Text Available The mouse lemur (Microcebus murinus is a promising primate model for investigating normal and pathological cerebral aging. The locomotor behavior of this arboreal primate is characterized by jumps to and from trunks and branches. Many reports indicate insufficient adaptation of the mouse lemur to experimental devices used to evaluate its cognition, which is an impediment to the efficient use of this animal in research. In order to develop cognitive testing methods appropriate to the behavioral and biological traits of this species, we adapted the Lashley jumping stand apparatus, initially designed for rats, to the mouse lemur. We used this jumping stand apparatus to compare performances of young (n = 12 and aged (n = 8 adults in acquisition and long-term retention of visual discriminations. All mouse lemurs completed the tasks and only 25 trials, on average, were needed to master the first discrimination problem with no age-related differences. A month later, all mouse lemurs made progress for acquiring the second discrimination problem but only the young group reached immediately the criterion in the retention test of the first discrimination problem. This study shows that the jumping stand apparatus allows rapid and efficient evaluation of cognition in mouse lemurs and demonstrates that about half of the old mouse lemurs display a specific deficit in long-term retention but not in acquisition of visual discrimination.

  2. Diameter distribution in a Brazilian tropical dry forest domain: predictions for the stand and species.

    Science.gov (United States)

    Lima, Robson B DE; Bufalino, Lina; Alves, Francisco T; Silva, José A A DA; Ferreira, Rinaldo L C

    2017-01-01

    Currently, there is a lack of studies on the correct utilization of continuous distributions for dry tropical forests. Therefore, this work aims to investigate the diameter structure of a brazilian tropical dry forest and to select suitable continuous distributions by means of statistic tools for the stand and the main species. Two subsets were randomly selected from 40 plots. Diameter at base height was obtained. The following functions were tested: log-normal; gamma; Weibull 2P and Burr. The best fits were selected by Akaike's information validation criterion. Overall, the diameter distribution of the dry tropical forest was better described by negative exponential curves and positive skewness. The forest studied showed diameter distributions with decreasing probability for larger trees. This behavior was observed for both the main species and the stand. The generalization of the function fitted for the main species show that the development of individual models is needed. The Burr function showed good flexibility to describe the diameter structure of the stand and the behavior of Mimosa ophthalmocentra and Bauhinia cheilantha species. For Poincianella bracteosa, Aspidosperma pyrifolium and Myracrodum urundeuva better fitting was obtained with the log-normal function.

  3. The experiences of mastery of stand-by energy demand; Les experiences de MDE stand by

    Energy Technology Data Exchange (ETDEWEB)

    Schilken, P.

    2001-07-01

    In the residential sector of the OECD countries, the electricity losses of domestic appliances in stand-by position represent 1.5% of the total electricity consumption. This study belongs to the SAVE project (pilot campaign of municipal utilities for an improved rational use of energy). Its aim is to observe the policies and experiments implemented by municipalities and municipal energy companies for the abatement of the electricity consumptions of stand-by origin. A working group consisting of the German Stadtwerke and some international partners have debated the possible actions and documents for an efficient information of the public. This document presents the brochures and local actions of this program. (J.S.)

  4. Using a stand-level model to predict light absorption in stands with vertically and horizontally heterogeneous canopies

    Directory of Open Access Journals (Sweden)

    David I Forrester

    2014-09-01

    Full Text Available Background Forest ecosystem functioning is strongly influenced by the absorption of photosynthetically active radiation (APAR, and therefore, accurate predictions of APAR are critical for many process-based forest growth models. The Lambert-Beer law can be applied to estimate APAR for simple homogeneous canopies composed of one layer, one species, and no canopy gaps. However, the vertical and horizontal structure of forest canopies is rarely homogeneous. Detailed tree-level models can account for this heterogeneity but these often have high input and computational demands and work on finer temporal and spatial resolutions than required by stand-level growth models. The aim of this study was to test a stand-level light absorption model that can estimate APAR by individual species in mixed-species and multi-layered stands with any degree of canopy openness including open-grown trees to closed canopies. Methods The stand-level model was compared with a detailed tree-level model that has already been tested in mixed-species stands using empirical data. Both models were parameterised for five different forests, including a wide range of species compositions, species proportions, stand densities, crown architectures and canopy structures. Results The stand-level model performed well in all stands except in the stand where extinction coefficients were unusually variable and it appears unlikely that APAR could be predicted in such stands using (tree- or stand-level models that do not allow individuals of a given species to have different extinction coefficients, leaf-area density or analogous parameters. Conclusion This model is parameterised with species-specific information about extinction coefficients and mean crown length, diameter, height and leaf area. It could be used to examine light dynamics in complex canopies and in stand-level growth models.

  5. Rotating and standing waves in a diffractive nonlinear optical system with delayed feedback under O(2) Hopf bifurcation

    Science.gov (United States)

    Budzinskiy, S. S.; Razgulin, A. V.

    2017-08-01

    In this paper we study one-dimensional rotating and standing waves in a model of an O(2)-symmetric nonlinear optical system with diffraction and delay in the feedback loop whose dynamics is governed by a system of coupled delayed parabolic equation and linear Schrodinger-type equation. We elaborate a two-step approach: transition to a rotating coordinate system to obtain the profiles of the waves as small parameter expansions and the normal form technique to study their qualitative dynamic behavior and stability. Theoretical results stand in a good agreement with direct computer simulations presented.

  6. Topic 1.1.2, Unsteady Aerodynamics: Time-Varying Compressible Dynamic Stall Mechanisms Due to Freestream Mach Oscillations

    Science.gov (United States)

    2014-12-31

    Chandrasekhara and Carr, 1990), development of a point diffraction interferometry system for quantitative visualization of DS vortex behavior (Carr et...b) thrust bearing for pitch oscillation. Connection Bar Movement Lever Arm Fly Wheel Eccentric Disk V-Belt 5-hp A/C Motor Flow Pulley diameter...connected to an ESP Pressure Scanner System to obtain the static pressure distribution along the airfoil surface. The pressure-coefficient (Cp) is

  7. Spectroscopy of Single Free Standing Quantum Wells

    International Nuclear Information System (INIS)

    Williams, M D; Hollars, C W; Huser, T; Jallow, N; Cochran, A; Bryant, R

    2006-01-01

    We investigated the interaction of quantum confined exciton states GaAs quantum wells with native surface states. Single molecule photoluminescence (PL) spectroscopy, developed by T. Huser at LLNL was used to probe the unique bare quantum wells in the free standing quantum well structure. The latter was developed by the M. D. Williams at Clark Atlanta University. The goals of the project during this budget cycle were to procure samples containing GaAs free standing QWs, identify suitable regions for PL analysis at Lawrence Livermore, analyze the structures at room temperature and at liquid nitrogen temperatures. The specific regions of interest on the sample structures were identified by scanning electron microscopy at Clark Atlanta prior to transport to LLNL. Previous attempts at other facilities using NSOM, cathodoluminescence, and conventional PL showed little luminescence activity at room temperature from the 200 (angstrom) thick wells. This suggested either excess recombination due to surface states in the quantum well region or insufficient absorption length for photoluminescence. The literature suggested that the effect of the defects could be eliminated by reducing the sample temperature below their associated activation energies. In our previous subcontract work with LLNL, a significant amount of effort was expended to modify the apparatus to allow low temperature measurements. The modifications were not successful and we concluded that in order to do the measurements at low temperature we would need to purchase a commercial optical cryostat to get reliable results. Ms. Rochelle Bryant worked during the summer as an intern at LLNL on the project under the supervision of C. Hollars and in collaboration with T. Huser and found that PL emission could be obtained at room temperature. This was a surprising result as the literature and our experience shows that there is no PL emission from GaAs at room temperature. We speculate that this is due to the small

  8. Reflections on "Verbal Behavior" at 60

    Science.gov (United States)

    Schlinger, Henry D., Jr.

    2017-01-01

    In the present essay, commemorating the 60th anniversary of the publication of B. F. Skinner's "Verbal Behavior", I stand by and defend the judgment I expressed in my article "The Long Goodbye: Why B. F. Skinner's 'Verbal Behavior' Is Alive and Well on the 50th Anniversary of Its Publication" (2008c)--that Skinner's…

  9. Effects of clear visual input and change in standing sequence on standing sway related to falls during night toilet use.

    Science.gov (United States)

    Sada, Kouji; Uchiyama, Junko; Ohnishi, Toshihiko; Ninomiya, Ishio; Masino, Yachiyo

    2010-03-01

    The aim of this study is to provide objective evidence that clear visual input and change in standing sequence can reduce fall risk related to night toilet use among hospitalized older patients. In hospitalized older patients, falls are likely to occur during night toileting needs. Using a stabilometer, we measured and compared maximal standing sway for 10 seconds immediately after standing with three visual input modes in two standing patterns, comparing healthy younger adults (n=22) and older patients (n=19). The three modes are no visual input (mode 1), vague (mode 2), and clear visual input (mode 3). Standing sequences A and B are defined as supine-to-standing and supine-to-sitting-to-standing, respectively. For a given visual mode, maximal moved distance was significantly greater for older patients than for younger adults with both standing patterns (Polder patients. A greater maximal moved distance score indicated a greater fall risk. It is important for nurses to train older patients to turn on the light and perform standing pattern B, when going to the bathroom at night. In addition, it is advisable to confirm the placement of distinct visual markers on the way to the bathroom. © 2009 Blackwell Publishing Ltd.

  10. Free-standing NiTi alloy nanowires fabricated by nanoskiving.

    Science.gov (United States)

    Hou, Huilong; Hamilton, Reginald F

    2015-08-28

    We report on free-standing NiTi alloy nanowires (120 nm × 75 nm) fabricated using a technique referred to as "nanoskiving", which complements conventional thin film sputter deposition with ultramicrotomy for thin sectioning. To date, the technique has been limited to pure metals without exploring metallic alloys. Leveraging the technique for the fabrication of shape memory alloy (SMA) nanostructures meets two critical requirements: compositional control (via film deposition) and controlled dimensions (via film deposition and programmable sectioning). Microstructure and composition analysis confirm continuity of the produced nanowires and Ni and Ti elemental uniformity. Free-standing NiTi nanowires are robust and remain intact throughout physical manipulation. The fabrication of NiTi alloy nanowires by nanoskiving will advance fundamental characterization of small scale SMA behavior.

  11. 2015 Occupant Protection Standing Review Panel

    Science.gov (United States)

    Steinberg, Susan

    2015-01-01

    The 2015 Occupant Protection (OP) Risk Standing Review Panel (from here on referred to as the SRP) participated in a WebEx/teleconference with members of the Space Human Factors and Habitability (SHFH) Element, representatives from the Human Research Program (HRP), NASA Headquarters, and NASA Research and Education Support Services on November 3, 2015 (list of participants is in Section VII of this report). The SRP reviewed the updated research plans for the Risk of Injury from Dynamic Loads (OP Risk). The SRP agrees that the Gaps are relevant and appropriate to mitigate the injury risk. All the appropriate and relevant Tasks have been identified to fill the Gaps. Depending upon the findings, additional tasks may need to be identified or modified. Excellent progress has been made since the 2014 SRP meeting. Publications in peer-reviewed journals validate the scientific merit of the research findings. As detailed in this report, the SRP has specific comments, guidance, and information in the following areas: human finite element modeling, human vs. surrogate dynamic responses, chest injury risk curves, matched pair testing of Test device for Human Occupant Restraint (THOR) and Hybrid III, and disc herniation risk analysis.

  12. Brookhaven National Laboratory electron beam test stand

    International Nuclear Information System (INIS)

    Pikin, A.; Alessi, J.; Beebe, E.; Kponou, A.; Prelec, K.; Snydstrup, L.

    1998-01-01

    The main purpose of the electron beam test stand (EBTS) project at the Brookhaven National Laboratory is to build a versatile device to develop technologies that are relevant for a high intensity electron beam ion source (EBIS) and to study the physics of ion confinement in a trap. The EBTS will have all the main attributes of EBIS: a 1-m-long, 5 T superconducting solenoid, electron gun, drift tube structure, electron collector, vacuum system, ion injection system, appropriate control, and instrumentation. Therefore it can be considered a short prototype of an EBIS for a relativistic heavy ion collider. The drift tube structure will be mounted in a vacuum tube inside a open-quotes warmclose quotes bore of a superconducting solenoid, it will be at room temperature, and its design will employ ultrahigh vacuum technology to reach the 10 -10 Torr level. The first gun to be tested will be a 10 A electron gun with high emission density and magnetic compression of the electron beam. copyright 1998 American Institute of Physics

  13. RAMSES stands guard over the accelerator chain

    CERN Document Server

    CERN Bulletin

    2010-01-01

    RAMSES, the system that is used to monitor radiation at the LHC, CNGS, CTF3 and n-TOF facilities, will soon be installed at strategic points in the accelerator chain, replacing the older monitoring system ARCON. The replacement programme has already begun.   RAMSES (which stands for “Radiation Monitoring System for the Environment and Safety”) is designed to protect workers, the general public and the environment, both on the Organization’s site and in the surrounding areas. It is currently operational on all the LHC sites and at CTF3, CNGS and n-TOF, while the remaining sites are still equipped with the ARCON (Area CONtroller) system. Daniel Perrin, head of the Instrumentation and Logistics Section of the HSE Unit's Radiation Protection Group, explains: “ARCON was designed for the old LEP accelerator and dates back to the early 1980s, while RAMSES is a much more recent design intended specifically for the LHC. With 389 detectors distributed across 124 mea...

  14. Visual evoked responses during standing and walking

    Directory of Open Access Journals (Sweden)

    Klaus Gramann

    2010-10-01

    Full Text Available Human cognition has been shaped both by our body structure and by its complex interactionswith its environment. Our cognition is thus inextricably linked to our own and others’ motorbehavior. To model brain activity associated with natural cognition, we propose recording theconcurrent brain dynamics and body movements of human subjects performing normal actions.Here we tested the feasibility of such a mobile brain/body (MoBI imaging approach byrecording high-density electroencephalographic (EEG activity and body movements of subjectsstanding or walking on a treadmill while performing a visual oddball response task. Independentcomponent analysis (ICA of the EEG data revealed visual event-related potentials (ERPs thatduring standing, slow walking, and fast walking did not differ across movement conditions,demonstrating the viability of recording brain activity accompanying cognitive processes duringwhole body movement. Non-invasive and relatively low-cost MoBI studies of normal, motivatedactions might improve understanding of interactions between brain and body dynamics leadingto more complete biological models of cognition.

  15. Litterfall and Nutrient Returns in Isolated Stands of Terminalia ...

    African Journals Online (AJOL)

    This study assesses litter production, concentrations and returns of nutrient elements with respect to seasons, so as to provide empirical information on nutrient flux by the isolated exotic stands of Terminalia. Litterfall samples were collected from the isolated stands of Terminalia catappa and adjoining native rainforest which ...

  16. Heavy thinning of ponderosa pine stands: An Arizona case study

    Science.gov (United States)

    Peter F. Ffolliott; Jr. Baker; Gerald J. Gottfried

    2000-01-01

    Growth and structural changes in a mosaic of even-aged ponderosa pine (Pinus ponderosa) stands were studied for 25 years to determine the long-term impacts of a heavy thinning treatment to a basal-area level of 25 ft2/acre. Basal area and volume growth of these stands has increased since thinning and likely will continue to...

  17. Impact of Stand Management Practices on Beetle Diversity

    Science.gov (United States)

    Stephen P. Cook

    2004-01-01

    Abstract - Insects are useful indicators of change within ecosystems because of their abundance, richness and functional importance. Stand management practices impact the insect community within a forest. Therefore, the objective of the project is to determine the impact of various stand management practices on the diversity of beetles within...

  18. A whole stand basal area projection model for Appalachian hardwoods

    Science.gov (United States)

    John R. Brooks; Lichun Jiang; Matthew Perkowski; Benktesh Sharma

    2008-01-01

    Two whole-stand basal area projection models were developed for Appalachian hardwood stands. The proposed equations are an algebraic difference projection form based on existing basal area and the change in age, trees per acre, and/or dominant height. Average equation error was less than 10 square feet per acre and residuals exhibited no irregular trends.

  19. Evaluation of three classifiers in mapping forest stand types using ...

    African Journals Online (AJOL)

    Three classifiers were examined for their suitability in mapping the different forest stand types in the area (maximum likelihood, spectral angle mapper and decision tree). The results showed that using maximum likelihood classifier and ASTER imagery, different forest stand types can be accurately mapped with an overall ...

  20. 39 CFR 122.2 - Stand-alone special services.

    Science.gov (United States)

    2010-07-01

    ... 39 Postal Service 1 2010-07-01 2010-07-01 false Stand-alone special services. 122.2 Section 122.2 Postal Service UNITED STATES POSTAL SERVICE POST OFFICE SERVICES [DOMESTIC MAIL] SERVICE STANDARDS FOR MARKET-DOMINANT SPECIAL SERVICES PRODUCTS § 122.2 Stand-alone special services. (a) The service standard...

  1. Stand structure and stocking control in Appalachian mixed hardwoods

    Science.gov (United States)

    George R., Jr. Trimble; H. Clay Smith

    1976-01-01

    Uneven-aged management using a "q" technique for structure control is discussed for Appalachian mixed hardwoods. The success in attaining stand structure goals with periodic selection cuts was evaluated. Where these goals had not been reached, the authors speculated, on the basis of current stand conditions, whether they would be reached, and if so, when. For...

  2. Vibration transmission characteristics of the legs of freely standing honeybees

    DEFF Research Database (Denmark)

    Rohrseitz, Kristin; Kilpinen, Ole

    1997-01-01

    The leg vibrations of honeybees standing on a vibrating substrate were measured with laser Doppler vibrometry, both in freely standing bees and in bees attached to a holder. In both cases, no resonances were found. In the fixed bee preparation, the legs moved with approximately the same amplitude...

  3. Ampere hour method of sizing a stand alone photovoltaic system ...

    African Journals Online (AJOL)

    Stand-alone photovoltaic power systems are natural options for application in electrification of remote areas which are not served by the grid electricity supply system. An ampere-hour method of sizing a stand-alone PV system for application in any remote location has been presented. The design which is for both ac and dc ...

  4. Flooding effects on stand development in cypress-tupelo

    Science.gov (United States)

    Richard F. Keim; Thomas J. Dean; Jim L. Chambers

    2013-01-01

    The effects of inundation on growth of cypress (Taxodium spp.) and tupelo (Nyssa spp.) trees have been extensively researched, but conclusions are often complicated by attendant effects on stand development. Flooding affects development of cypress-tupelo stands by limiting seedling germination and survival, truncating species...

  5. The importance of spatial accuracy in characterizing stand types ...

    African Journals Online (AJOL)

    This study assessed the potential use of Landsat 7 ETM+ (15 and 30 m spatial resolutions) images to estimate forest stand attributes such as development stages, crown closure and stand types. The study evaluates the performance of spatial and image classification accuracies between Landsat images (15 and 30 m ...

  6. Rapid economic analysis of northern hardwood stand improvement options

    Science.gov (United States)

    William B. Leak

    1980-01-01

    Data and methodology are provided for projecting basal area, diameter, volumes, and values by product for northern hardwood stands, and for determining the rate of return on stand improvement investments. The method is rapid, requires a minimum amount of information, and should prove useful for on-the-ground economic analyses.

  7. The role of forest stand structure as biodiversity indicator

    DEFF Research Database (Denmark)

    Gao, Tian; Hedblom, Marcus; Emilsson, Tobias

    2014-01-01

    be achieved if indicators are derived from existing data. In this study, a model for classifying forest stand structures was developed and tested as an indicator of overall plant species diversity at stand level. The model combines four stand structure parameters: canopy coverage, age of canopy trees, tree...... species composition and canopy stratification. Using data from the National Inventory of Landscapes in Sweden and General Linear Mixed Model, plant species diversity (Shannon diversity index, SHDI) and composition (Sørensen-Dice index, SDI) were tested between 26 different stand structure types and nine...... soil classes. The results showed that mature stands with a stratified canopy had the highest plant species diversity across the soil classes, particularly if they comprised mixed coniferous and broadleaved species with a semi-open canopy. In contrast, young (...

  8. How Settings Change People: Applying Behavior Setting Theory to Consumer-Run Organizations

    Science.gov (United States)

    Brown, Louis D.; Shepherd, Matthew D.; Wituk, Scott A.; Meissen, Greg

    2007-01-01

    Self-help initiatives stand as a classic context for organizational studies in community psychology. Behavior setting theory stands as a classic conception of organizations and the environment. This study explores both, applying behavior setting theory to consumer-run organizations (CROs). Analysis of multiple data sets from all CROs in Kansas…

  9. Desk-based workers' perspectives on using sit-stand workstations: a qualitative analysis of the Stand@Work study

    NARCIS (Netherlands)

    Chau, J.Y.; Daley, M.; Srinivasan, A.; Dunn, S.; Bauman, A.E.; van der Ploeg, H.P.

    2014-01-01

    Background: Prolonged sitting time has been identified as a health risk factor. Sit-stand workstations allow desk workers to alternate between sitting and standing throughout the working day, but not much is known about their acceptability and feasibility. Hence, the aim of this study was to

  10. Growth of site trees and stand structure in mixed stands of Pacific silver fir and western hemlock.

    Science.gov (United States)

    Marshall D. Murray; Peggy C. Leonard

    1990-01-01

    Height and diameter growth of Pacific silver fir (Abies amabilis Dougl. ex Forbes) and western hemlock (Tsuga heterophylla (Raf.) Sarg.) site trees, as well as overall stand structure on 0.15-acre plots, were analyzed in mixed stands 43 to 57 years old in breast height age at six locations in western Washington. These mixed...

  11. Stand Structure and Composition 32 Years after Precommercial Thinning Treatments in a Mixed Northern Conifer Stand in Central Maine

    Science.gov (United States)

    Aaron R. Weiskittel; Laura S. Kenefic; Rongxia Li; John Brissette

    2011-01-01

    The effects of four precommercial thinning (PCT) treatments on an even-aged northern conifer stand in Maine were investigated by examining stand structure and composition 32 years after treatment. Replicated treatments applied in 1976 included: (1) control (no PCT), (2) row thinning (rowthin; 5-ft-wide row removal with 3-ft-wide residual strips), (3) row thinning with...

  12. How to formulate and solve "optimal stand density over time" problems for even-aged stands using dynamic programming.

    Science.gov (United States)

    Chung M. Chen; Dietmar W. Rose; Rolfe A. Leary

    1980-01-01

    Describes how dynamic programming can be used to solve optimal stand density problems when yields are given by prior simulation or by a new stand growth equation that is a function of the decision variable. Formulations of the latter type allow use of a calculus-based search procedure; they determine exact optimal residual density at each stage.

  13. Effects of stand and inter-specific stocking on maximizing standing tree carbon stocks in the eastern United States

    Science.gov (United States)

    Christopher W. Woodall; Anthony W. D' Amato; John B. Bradford; Andrew O. Finley

    2011-01-01

    There is expanding interest in management strategies that maximize forest carbon (C) storage to mitigate increased atmospheric carbon dioxide. The tremendous tree species diversity and range of stand stocking found across the eastern United States presents a challenge for determining optimal combinations for the maximization of standing tree C storage. Using a...

  14. Trailed vorticity modeling for aeroelastic wind turbine simulations in stand still

    DEFF Research Database (Denmark)

    Pirrung, Georg; Aagaard Madsen, Helge; Schreck, Scott

    2016-01-01

    Current fast aeroelastic wind turbine codes suitable for certification lack an induction model for standstill conditions. A trailed vorticity model previously used as addition to a blade element momentum theory based aerodynamic model in normal operation has been extended to allow computing...... the steady loading for the Phase VI blade in attached flow. The prediction of the dynamic force coefficient loops from the Phase VI experiment is improved by the trailed vorticity modeling in both attached flow and stall in most cases. The exception is the tangential force coefficient in stall, where...

  15. Financial Village Standing in Indonesian Financial System

    Directory of Open Access Journals (Sweden)

    Herry Purnomo

    2015-12-01

    Full Text Available Financial resources of the village that are sourced from a country or a Regional Finance Financial based Law Number 6 Year 2014 of The Village is the mandate of the law that must be allocated to the village. The interconnectedness of the financial position of the village in the financial system of the country or Region concerned the Financial administrative and territorial relations, and there is no setting directly regarding the finances of the village as part of the financial system of the country or the financial area. In respect of the elements of the crime of corruption deeds against financial irregularities of the village there are still disagreements on the interpretation of the law in trapping the perpetrators of corruption on the village chief that implies not satisfy the principle of legality and legal certainty in the ruling of the matter of financial irregularities. In fact, many of the village chief or Councilor caught the criminal offence of corruption over the use of financial irregularities. This research analyzes How the financial position of the village in the financial system of the country or region, as well as whether the financial resources of the village is derived from the state budget or region budget managed in village budget belongs to the category of village finances and whether tort against the financial management of the village can be categorized as a criminal act corruption. How To Cite: Purnomo, H. (2015. Financial Village Standing in Indonesian Financial System. Rechtsidee, 2(2, 121-140. doi:http://dx.doi.org/10.21070/jihr.v2i2.81

  16. Plant growth regulators to manipulate oat stands

    Directory of Open Access Journals (Sweden)

    A. RAJALA

    2008-12-01

    Full Text Available Plant growth regulators (PGRs are exogenously applied chemicals that alter plant metabolism, cell division, cell enlargement, growth and development by regulating plant hormones or other biological signals. For example, some PGRs regulate stem elongation by inhibiting biosynthesis of gibberellins or through releasing ethylene. PGR effects are widely studied and reported on barley (Hordeum vulgare L. and wheat (Triticum aestivum L., whereas there are only a few reports addressing oat (Avena sativa L.. This is likely to be a result of smaller acreage and lower intensity of oat management and production and hence a reduced need for stem shortening by PGRs. However, this is not the case for all cereal producing regions and there exists a need to understand the potential application of PGRs to oat production. This paper represents a review of the potential of PGRs to regulate stem elongation and other biological traits governing plant stand structure and yield components, with special emphasis on oat and its responses to PGRs. Yield improvement requires more heads per unit land area, more grains per head or heavier grains. Of these yield-determining parameters, the number of head bearing tillers and grain numbers per head, compared with grain weight, are more likely to be improved by PGR application. In the absence of lodging, PGR may reduce grain yield due to potential reduction in mean grain weight and/or grain number. Cultivation systems aiming at extensive yields with intensive use of inputs likely benefit from PGR applications more often compared with low or moderate input cultivation, for which cost effectiveness of PGRs is not frequently reached.;

  17. The experiences of MDE stand-by; Les experiences de MDE stand-by

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    2001-02-01

    The control of the electric power demand (MDE) is a worrying subject for many countries. The consumption of the electrical equipment in stand-by, is evaluated at 20 TWh/year for the ternary and residential sectors in Germany and 5,3 in France. Taking into account the SAVE project (Pilot campaign of municipal utilities for an improved rational use of energy), this study aims to observe the policies and the experiences of local governments in terms of energy consumption reduction. (A.L.B.)

  18. Construction Progress of the F-1 Test Stand

    Science.gov (United States)

    1963-01-01

    At its founding, the Marshall Space Flight Center (MSFC) inherited the Army's Jupiter and Redstone test stands, but much larger facilities were needed for the giant stages of the Saturn V. From 1960 to 1964, the existing stands were remodeled and a sizable new test area was developed. The new comprehensive test complex for propulsion and structural dynamics was unique within the nation and the free world, and they remain so today because they were constructed with foresight to meet the future as well as on going needs. Construction of the S-IC Static test stand complex began in 1961 in the west test area of MSFC, and was completed in 1964. The S-IC static test stand was designed to develop and test the 138-ft long and 33-ft diameter Saturn V S-IC first stage, or booster stage, weighing in at 280,000 pounds. Required to hold down the brute force of a 7,500,000-pound thrust produced by 5 F-1 engines, the S-IC static test stand was designed and constructed with the strength of hundreds of tons of steel and 12,000,000 pounds of cement, planted down to bedrock 40 feet below ground level. The foundation walls, constructed with concrete and steel, are 4 feet thick. The base structure consists of four towers with 40-foot-thick walls extending upward 144 feet above ground level. The structure was topped by a crane with a 135-foot boom. With the boom in the upright position, the stand was given an overall height of 405 feet, placing it among the highest structures in Alabama at the time. North of the massive S-IC test stand, the F-1 Engine test stand was built. Designed to assist in the development of the F-1 Engine, the F-1 test stand is a vertical engine firing test stand, 239 feet in elevation and 4,600 square feet in area at the base. Capability was provided for static firing of 1.5 million pounds of thrust using liquid oxygen and kerosene. Like the S-IC stand, the foundation of the F-1 stand is keyed into the bedrock approximately 40 feet below grade. This photo shows

  19. Genetics of Keratoconus: Where Do We Stand?

    OpenAIRE

    Khaled K. Abu-Amero; Abdulrahman M. Al-Muammar; Altaf A. Kondkar

    2014-01-01

    Keratoconus is a progressive thinning and anterior protrusion of the cornea that results in steepening and distortion of the cornea, altered refractive powers, and reduced vision. Keratoconus has a complex multifactorial etiology, with environmental, behavioral, and multiple genetic components contributing to the disease pathophysiology. Using genome-wide and candidate gene approaches several genomic loci and genes have been identified that highlight the complex molecular etiology of this dis...

  20. Learning in Economics: Where Do We Stand?

    OpenAIRE

    Tilman Slembeck

    2000-01-01

    This paper briefly reviews the current literature on learning in economics from a behavioral point of view. It critically compares theory with aspects of learning in real-life and with evidence from laboratory experiments, and argues that most customary approaches lack criteria for their applicability. Hence, there is a need for a theory that includes criteria when to employ which theory or which element(s) of existing theories contingent on the situation or environment in question. A discuss...

  1. Characterizing energy expenditure during sedentary behavior after stroke

    NARCIS (Netherlands)

    Verschuren, Olaf; de Haan, Femke; Mead, Gillian; Fengler, Ben; Visser-Meily, Anne

    2015-01-01

    OBJECTIVE: To objectively measure and calculate the energy expended by people with stroke during near sedentary behaviors (lying, supported and unsupported sitting, standing, wheelchair propulsion and walking), under controlled laboratory conditions, and compare these values to the energy

  2. Isotope enrichment effect of gaseous mixtures in standing sound vibration

    International Nuclear Information System (INIS)

    Knesebeck, R.L.

    1984-01-01

    When standing acoustic waves are excited in a tube containing a mixture of two gases, a partial zonal fractioning of the components arises as consequence of mass transport by diffusion, driven by the thermal and pressure gradients which are associeted with the standing waves. This effect is present in each zone corresponding to a quarter wavelength, with the heavier component becoming enriched at the nodes fo the standing waves and deplected at the crests. The magnitude of the enrichment in one of the components of a binary gas mixture is given by Δω=ap 2 /lambda [b + (1-bω)] 2 . Where ω is the mass concentration of the component in the mixture, a and b are parameters which are related to molecular proprieties of the gases, p is the relative pressure amplitude of the standing wave and lambda is its wavelength. For a natural mixture of uranium hexafluorate, with 0.715% of the uranium isotope 340 an enrichment of about 2 x 10 -6 % in the concentration of this isotope is theorecticaly attainable per stage consisting of a quarter wavelenght, when a standing acoustical wave of relative pressure amplitude of 0,2 and wavelenght of 20 cm is used. Since standing acoustical waves are easely excited in gas columns, an isotope enrichment plant made of a cascade of tubes in which standing waves are excited, is presumably feasible with relatively low investment and operation costs. (Author) [pt

  3. Stand for testing the electrical race car engine

    Science.gov (United States)

    Baier, M.; Franiasz, J.; Mierzwa, P.; Wylenzek, D.

    2015-11-01

    An engine test stand created especially for research of electrical race car is described in the paper. The car is an aim of Silesian Greenpower project whose participants build and test electrical vehicles to take part in international races in Great Britain. The engine test stand is used to test and measure the characteristics of vehicles and their engines. It has been designed particularly to test the electric cars engineered by students of Silesian Greenpower project. The article contains a description how the test stand works and shows its versatility in many areas. The paper presents both construction of the test stand, control system and sample results of conducted research. The engine test stand was designed and modified using PLM Siemens NX 8.5. The construction of the test stand is highly modular, which means it can be used both for testing the vehicle itself or for tests without the vehicle. The test stand has its own wheel, motor, powertrain and braking system with second engine. Such solution enables verifying various concepts without changing the construction of the vehicle. The control system and measurement system are realized by enabling National Instruments product myRIO (RIO - Reconfigurable Input/Output). This controller in combination with powerful LabVIEW environment performs as an advanced tool to control torque and speed simultaneously. It is crucial as far as the test stand is equipped in two motors - the one being tested and the braking one. The feedback loop is realized by an optical encoder cooperating with the rotor mounted on the wheel. The results of tests are shown live on the screen both as a chart and as single values. After performing several tests there is a report generated. The engine test stand is widely used during process of the Silesian Greenpower vehicle design. Its versatility enables powertrain testing, wheels and tires tests, thermal analysis and more.

  4. Seed Quality in Five Jack Pine Stands in North Central Wisconsin

    Science.gov (United States)

    Richard M. Jeffers

    1985-01-01

    Hundred-seed weights from 15 trees in each stand averaged 330 mg; 100-seed weights differed significantly among trees within stands and among stands. Germination of filled seed averaged 95 percent; germination differed significantly among trees within stands, but not among stands. Detailed seed records should be kept for all seed orchards.

  5. Kahneman and Tversky and the Origin of Behavioral Economics

    NARCIS (Netherlands)

    Heukelom, F.

    2007-01-01

    Kahneman and Tversky and their behavioral economics stand in a long tradition of applying mathematics to human behavior. In the seventeenth century, attempts to describe rational behavior in mathematical terms run into problems with the formulation of the St. Petersburg paradox. Bernoulli’s

  6. Normal distribution of standing balance for healthy Danish children

    DEFF Research Database (Denmark)

    Pedersen, Line Kjeldgaard; Ghasemi, Habib; Rahbek, Ole

    2013-01-01

    in children with orthopedic disabilities undergoing surgical procedures. Recent technology provides extremely usable sway analysis of balance parameters but a normal material for the standing balance of healthy children is lacking. Purpose/Aim of Study First, to assess standing balance in healthy Danish...... compared to open eyes (p=0,0000) and this difference was strongest in the lower grades. Girls had a significantly better balance than boys with open and closed eyes especially in the higher grades. Conclusions In this study we measured the effect of BMI, age, gender and visual information on standing...

  7. Performing Arabness in Arab American Stand-up Comedy

    OpenAIRE

    Fouad Selim Yasser

    2014-01-01

    This article deals with the dramatic art of stand-up comedy. It locates Arab American stand-up comedy within a broader American humorous tradition and investigates the way Arab American performers use this art to negotiate and (re)construct their identity. The main question in this article is the way Arab American stand-up comedians define their relationship to the Arab and the western worlds in the process of establishing their Arab American identity. Three humor theories - the relief theory...

  8. A six-component force/moment sensor calibration stand

    Science.gov (United States)

    Estlow, Edward G. W.; Kovacevic, Nebojsa

    1990-06-01

    A compact portable stand for calibration of multicomponent internal balances is described. The stand is designed to control/eliminate misalignments between load trains and the balance being calibrated; it generates forces and moments with pneumatic cylinders for all but rolling moment, which is applied with conventional weights. Load application control is discussed, and performance is analyzed. It is noted that the calibration stand has the ability to sense off-axis loads resulting from distortion/deflections due to the primary loading. Having sensed these off-axis loads, the system can be adjusted to minimize or eliminate them while retaining correct alignment of the primary load with the balance.

  9. 2014 Space Radiation Standing Review Panel

    Science.gov (United States)

    Steinberg, Susan

    2015-01-01

    The 2014 Space Radiation Standing Review Panel (from here on referred to as the SRP) participated in a WebEx/teleconference with members of the Space Radiation Program Element, representatives from the Human Research Program (HRP), the National Space Biomedical Research Institute (NSBRI), and NASA Headquarters on November 21, 2014 (list of participants is in Section XI of this report). The SRP reviewed the updated Research Plan for the Risk of Cardiovascular Disease and Other Degenerative Tissue Effects from Radiation Exposure (Degen Risk). The SRP also received a status update on the Risk of Acute and Late Central Nervous System Effects from Radiation Exposure (CNS Risk), the Risk of Acute Radiation Syndromes Due to Solar Particle Events (ARS Risk), and the Risk of Radiation Carcinogenesis (Cancer Risk). The SRP thought the teleconference was very informative and that the Space Radiation Program Element did a great job of outlining where the Element is with respect to our state of knowledge on the risks of carcinogenesis, central nervous system effects, and the risk of cardiovascular disease and other degenerative tissue effects from exposure to space radiation. The SRP was impressed with the quality of research that is being conducted and the progress the Space Radiation Program Element has made in the past year. While much work has been done, the SRP had a few remaining questions regarding the broad applicability of these findings to a manned deep space mission (in terms of cognitive function, the paradigms were still hippocampal based and also using Alzheimer disease models). The SRP believes that NASA should consider developing an approach to follow astronauts long-term (beyond retirement) for potential side-effects/risks of space exposure that may be unknown. Radiation toxicities often occur decades after exposure, and potential consequences would be missed if intensified exams stop after retirement of the astronauts. In addition, while cancer is one

  10. Standing wave tube electro active polymer wave energy converter

    Science.gov (United States)

    Jean, Philippe; Wattez, Ambroise; Ardoise, Guillaume; Melis, C.; Van Kessel, R.; Fourmon, A.; Barrabino, E.; Heemskerk, J.; Queau, J. P.

    2012-04-01

    Over the past 4 years SBM has developed a revolutionary Wave Energy Converter (WEC): the S3. Floating under the ocean surface, the S3 amplifies pressure waves similarly to a Ruben's tube. Only made of elastomers, the system is entirely flexible, environmentally friendly and silent. Thanks to a multimodal resonant behavior, the S3 is capable of efficiently harvesting wave energy from a wide range of wave periods, naturally smoothing the irregularities of ocean wave amplitudes and periods. In the S3 system, Electro Active Polymer (EAP) generators are distributed along an elastomeric tube over several wave lengths, they convert wave induced deformations directly into electricity. The output is high voltage multiphase Direct Current with low ripple. Unlike other conventional WECs, the S3 requires no maintenance of moving parts. The conception and operating principle will eventually lead to a reduction of both CAPEX and OPEX. By integrating EAP generators into a small scale S3, SBM achieved a world first: direct conversion of wave energy in electricity with a moored flexible submerged EAP WEC in a wave tank test. Through an extensive testing program on large scale EAP generators, SBM identified challenges in scaling up to a utility grid device. French Government supports the consortium consisting of SBM, IFREMER and ECN in their efforts to deploy a full scale prototype at the SEMREV test center in France at the horizon 2014-2015. SBM will be seeking strategic as well as financial partners to unleash the true potentials of the S3 Standing Wave Tube Electro Active Polymer WEC.

  11. Construction of a test stand for the measurement of the light output uniformity of CALIFA crystals

    Energy Technology Data Exchange (ETDEWEB)

    Susenburger, Markus; Ignatov, Alexander; Kroell, Thorsten [Technische Universitaet Darmstadt, Darmstadt (Germany)

    2016-07-01

    Currently, the Facility for Antiproton and Ion Research (FAIR) at GSI in Darmstadt is under construction. One experiment at GSI and FAIR is called Reactions with Relativistic Radioactive Beams (R{sup 3}B). A key component of the R{sup 3}B is the CALorimeter for In Flight detection of γ-rays and light charged pArticles (CALIFA), which will surround the R{sup 3}B target chamber and will be capable of the detection of γ-rays in a wide energy range from 100 keV to 30 MeV as well as of light charged particles. CALIFA is built out of two parts, the so called CALIFA barrel and CALIFA endcap. The barrel consists of 1952 CsI(Tl) detector crystals which have to fulfill several specifications. One of these specifications is the uniformity of the light output. Depending on the location of the deposited energy, the crystal's light output varies due to optical focusing effects. This behavior can be manipulated by lapping the crystal's surface. The aim of this work is the development of a test stand which will check if the crystals match the requirements according to the light output uniformity. Because of the large number of crystals needed to be tested, the stand automates the test procedure, which guarantees comparable test measurement for all crystals. The development and construction of this stand is reported.

  12. Genetics of Keratoconus: Where Do We Stand?

    Science.gov (United States)

    Abu-Amero, Khaled K.; Al-Muammar, Abdulrahman M.; Kondkar, Altaf A.

    2014-01-01

    Keratoconus is a progressive thinning and anterior protrusion of the cornea that results in steepening and distortion of the cornea, altered refractive powers, and reduced vision. Keratoconus has a complex multifactorial etiology, with environmental, behavioral, and multiple genetic components contributing to the disease pathophysiology. Using genome-wide and candidate gene approaches several genomic loci and genes have been identified that highlight the complex molecular etiology of this disease. The review focuses on current knowledge of these genetic risk factors associated with keratoconus. PMID:25254113

  13. Genetics of Keratoconus: Where Do We Stand?

    Directory of Open Access Journals (Sweden)

    Khaled K. Abu-Amero

    2014-01-01

    Full Text Available Keratoconus is a progressive thinning and anterior protrusion of the cornea that results in steepening and distortion of the cornea, altered refractive powers, and reduced vision. Keratoconus has a complex multifactorial etiology, with environmental, behavioral, and multiple genetic components contributing to the disease pathophysiology. Using genome-wide and candidate gene approaches several genomic loci and genes have been identified that highlight the complex molecular etiology of this disease. The review focuses on current knowledge of these genetic risk factors associated with keratoconus.

  14. Isopropyl alcohol tank installed at A-3 Test Stand

    Science.gov (United States)

    2009-01-01

    An isopropyl alcohol (IPA) tank is lifted into place at the A-3 Test Stand being built at NASA's John C. Stennis Space Center. Fourteen IPA, water and liquid oxygen (LOX) tanks are being installed to support the chemical steam generators to be used on the A-3 Test Stand. The IPA and LOX tanks will provide fuel for the generators. The water will allow the generators to produce steam that will be used to reduce pressure inside the stand's test cell diffuser, enabling operators to simulate altitudes up to 100,000 feet. In that way, operators can perform the tests needed on rocket engines being built to carry humans back to the moon and possibly beyond. The A-3 Test Stand is set for completion and activation in 2011.

  15. Infrared differential absorption lidar for stand-off detection of ...

    Indian Academy of Sciences (India)

    2014-02-14

    ) carbon dioxide laser-based differential absorption lidar (DIAL) system capable of stand-off detection of chemical clouds in aerosol and vapour form upto about 200 m range in the atmosphere has been developed and ...

  16. Structural attributes of stand overstory and light under the canopy

    Directory of Open Access Journals (Sweden)

    Alice Angelini

    2015-02-01

    Full Text Available  This paper reviews the literature relating to the relationship between light availability in the understory and the main qualitative and quantitative attributes of stand overstory usually considered in forest management and planning (species composition, density, tree sizes, etc. as well as their changes as consequences of harvesting. The paper is divided in two sections: the first one reviews studies which investigated the influence of species composition on understory light conditions; the second part examines research on the relationships among stand parameters determined from dendrometric field data and the radiation on understory layer. The objective was to highlight which are the most significant stand traits and management features to build more practical models for predicting light regimes in any forest stand and, in more general terms, to support forest managers in planning and designing silvicultural treatments that retain structure in different way in order to meet different objectives.

  17. A comparison of soil moisture relations between standing and ...

    African Journals Online (AJOL)

    A comparison of soil moisture relations between standing and clearfelled plots with burnt and unburnt harvest residue treatments of a clonal eucalypt plantation on the Zululand Coastal Plain, South Africa.

  18. Basic Stand Alone Skilled Nursing Facility Beneficiary PUF

    Data.gov (United States)

    U.S. Department of Health & Human Services — This release contains the Basic Stand Alone (BSA) Skilled Nursing Facility (SNF) Beneficiary Public Use Files (PUF) with information from Medicare SNF claims. The...

  19. Basic Stand Alone Medicare Home Health Beneficiary PUF

    Data.gov (United States)

    U.S. Department of Health & Human Services — This release contains the Basic Stand Alone (BSA) Home Health Agency (HHA) Beneficiary Public Use Files (PUF) with information from Medicare HHA claims. The CMS BSA...

  20. Sagittal evaluation of usual standing and sitting spinal posture.

    Science.gov (United States)

    Claeys, Kurt; Brumagne, Simon; Deklerck, Jan; Vanderhaeghen, Jacques; Dankaerts, Wim

    2016-04-01

    Postural rehabilitation often plays an important role in the management of non-specific low back pain. While cervical and lumbar correlations have been demonstrated previously, the different role of the pelvis and the thoracic spine for postural control in sitting and standing remains unclear. The aim of this study was to investigate postural correlations between all spinal regions in standing and sitting. Based on digital photographs eight postural angles were analyzed in 99 young healthy persons. Pearson correlations between different postural angles were calculated. In sitting pelvic tilt demonstrated mostly medium correlations with five out of seven other postural angles, compared to three in standing. In standing trunk angle showed five out of seven mostly medium correlations with other regions compared to four out of seven in usual sitting. The low and different correlations suggest a large between-subject variability in sagittal spinal posture, without the existence of any optimal sagittal posture. Copyright © 2015 Elsevier Ltd. All rights reserved.

  1. Basic Stand Alone Medicare DME Line Items PUF

    Data.gov (United States)

    U.S. Department of Health & Human Services — This release contains the Basic Stand Alone (BSA) Durable Medical Equipment (DME) Line Items Public Use Files (PUF) with information from Medicare DME claims. The...

  2. Validation of Standing Wave Liner Impedance Measurement Method, Phase I

    Data.gov (United States)

    National Aeronautics and Space Administration — Hersh Acoustical Engineering, Inc. proposes to establish the feasibility and practicality of using the Standing Wave Method (SWM) to measure the impedance of...

  3. Robot-supported assessment of balance in standing and walking

    NARCIS (Netherlands)

    Shirota, Camila; van Asseldonk, Edwin; Matjacic, Zlatko; Vallery, H.; Barralon, Pierre; Maggioni, Serena; Buurke, Jaap H.; Veneman, Jan F.

    2017-01-01

    Clinically useful and efficient assessment of balance during standing and walking is especially challenging in patients with neurological disorders. However, rehabilitation robots could facilitate assessment procedures and improve their clinical value. We present a short overview of balance

  4. Engine Test Stand Design Constraints Expert System, Phase I

    Data.gov (United States)

    National Aeronautics and Space Administration — Propulsion test stands are designed for thermal and pressure loads for certain classes of engines. These plume induced loads are: radiative heating, acoustics and...

  5. Long-standing temporomandibular joint dislocation: A rare experience

    Directory of Open Access Journals (Sweden)

    Kapil Malik

    2017-01-01

    Full Text Available Long-standing temporomandibular joint (TMJ dislocations persist for more than a month are most challenging to treat. The management of such condition varies widely, from closed reduction to complicated surgical procedures. The choice of an appropriate methodology is questionable. At present, there are no standard rules or conventions for the ideal strategy in different circumstances. This paper attempts to present the experience of managing two cases of long-standing TMJ dislocations.

  6. Standing Wave Field Distribution in Graded-Index Antireflection Coatings

    Directory of Open Access Journals (Sweden)

    Hongxiang Deng

    2018-01-01

    Full Text Available Standing wave field distributions in three classic types of graded-index antireflection coatings are studied. These graded-index antireflection coatings are designed at wavelengths from 200 nm to 1200 nm, which is the working wavelength range of high energy laser system for inertial-fusion research. The standing wave field distributions in these coatings are obtained by the numerical calculation of electromagnetic wave equation. We find that standing wave field distributions in these three graded-index anti-reflection coatings are quite different. For the coating with linear index distribution, intensity of standing wave field decreases periodically from surface to substrate with narrow oscillation range and the period is proportional to the incident wavelength. For the coating with exponential index distribution, intensity of standing wave field decreases periodically from surface to substrate with large oscillation range and the period is also proportional to the incident wavelength. Finally, for the coating with polynomial index, intensity of standing wave field is quickly falling down from surface to substrate without an obvious oscillation. We find that the intensity of standing wave field in the interface between coating and substrate for linear index, exponential index and polynomial index are about 0.7, 0.9 and 0.7, respectively. Our results indicate that the distributions of standing wave field in linear index coating and polynomial index coating are better than that in exponential index coating for the application in high energy laser system. Moreover, we find that the transmittance of linear index coating and polynomial index coating are also better than exponential index coating at the designed wavelength range. Present simulation results are useful for the design and application of graded-index antireflection coating in high energy laser system.

  7. Thrust stand for low-thrust liquid pulsed rocket engines

    Science.gov (United States)

    Xing, Qin; Zhang, Jun; Qian, Min; Jia, Zhen-yuan; Sun, Bao-yuan

    2010-09-01

    A thrust stand is developed for measuring the pulsed thrust generated by low-thrust liquid pulsed rocket engines. It mainly consists of a thrust dynamometer, a base frame, a connecting frame, and a data acquisition and processing system. The thrust dynamometer assembled with shear mode piezoelectric quartz sensors is developed as the core component of the thrust stand. It adopts integral shell structure. The sensors are inserted into unique double-elastic-half-ring grooves with an interference fit. The thrust is transferred to the sensors by means of static friction forces of fitting surfaces. The sensors could produce an amount of charges which are proportional to the thrust to be measured. The thrust stand is calibrated both statically and dynamically. The in situ static calibration is performed using a standard force sensor. The dynamic calibration is carried out using pendulum-typed steel ball impact technique. Typical thrust pulse is simulated by a trapezoidal impulse force. The results show that the thrust stand has a sensitivity of 25.832 mV/N, a linearity error of 0.24% FSO, and a repeatability error of 0.23% FSO. The first natural frequency of the thrust stand is 1245 Hz. The thrust stand can accurately measure thrust waveform of each firing, which is used for fine control of on-orbit vehicles in the thrust range of 5-20 N with pulse frequency of 50 Hz.

  8. Engineers conduct key water test for A-3 stand

    Science.gov (United States)

    2009-01-01

    Water cascades from the A-2 Test Stand at Stennis Space Center as engineers challenge the limits of the high-pressure water system as part of the preparation process for the A-3 Test Stand under construction. Jeff Henderson, test director for Stennis' A Complex, led a series of tests Nov. 16-20, flowing water simultaneously on the A-1 and A-2 stands, followed by the A-1 and B-1 stands, to determine if the high-pressure industrial water facility pumps and the existing pipe system can support the needs of the A-3 stand. The stand is being built to test rocket engines that will carry astronauts beyond low-Earth orbit and will need about 300,000 gallons of water per minute when operating, but the Stennis system never had been tested to that level. The recent tests were successful in showing the water facility pumps can operate at that capacity - reaching 318,000 gallons per minute in one instance. However, officials continue to analyze data to determine if the system can provide the necessary pressure at that capacity and if the delivery system piping is adequate. 'We just think if there's a problem, it's better to identify and address it now rather than when A-3 is finished and it has to be dealt with,' Henderson said.

  9. Mixing Effects in Norway Spruce—European Beech Stands Are Modulated by Site Quality, Stand Age and Moisture Availability

    Directory of Open Access Journals (Sweden)

    Léa Houpert

    2018-02-01

    Full Text Available Although mixing tree species is considered an efficient risk-reduction strategy in the face of climate change, the conditions where mixtures are more productive than monocultures are under ongoing debate. Generalizations have been difficult because of the variety of methods used and due to contradictory findings regarding the effects of the species investigated, mixing proportions, and many site and stand conditions. Using data from 960 plots of the Swiss National Forest Inventory data, we assessed whether Picea abies (L. Karst–Fagus sylvatica L. mixed stands are more productive than pure stands, and whether the mixing effect depends on site- or stand-characteristics. The species proportions were estimated using species proportion by area, which depends on the maximum stand basal area of an unmanaged stand (BAmax. Four different alternatives were used to estimate BAmax and to investigate the effect of these differing alternatives on the estimated mixture effect. On average, the mixture had a negative effect on the growth of Picea abies. However, this effect decreased as moisture availability increased. Fagus sylvatica grew better in mixtures and this effect increased with site quality. A significant interaction between species proportions and quadratic mean diameter, a proxy for stand age, was found for both species: the older the stand, the better the growth of Fagus sylvatica and the lower the growth of Picea abies. Overyielding was predicted for 80% of the investigated sites. The alternative to estimate BAmax weakly modulated the estimated mixture effect, but it did not affect the way mixing effects changed with site characteristics.

  10. Study of the human postural control system during quiet standing using detrended fluctuation analysis

    Science.gov (United States)

    Teresa Blázquez, M.; Anguiano, Marta; de Saavedra, Fernando Arias; Lallena, Antonio M.; Carpena, Pedro

    2009-05-01

    The detrended fluctuation analysis is used to study the behavior of different time series obtained from the trajectory of the center of pressure, the output of the activity of the human postural control system. The results suggest that these trajectories present two different regimes in their scaling properties: persistent (for high frequencies, short-range time scale) to antipersistent (for low frequencies, long-range time scale) behaviors. The similitude between the results obtained for the measurements, done with both eyes open and eyes closed, indicate either that the visual system may be disregarded by the postural control system while maintaining the quiet standing, or that the control mechanisms associated with each type of information (visual, vestibular and somatosensory) cannot be disentangled with the type of analysis performed here.

  11. What COP and Kinematic Parameters Better Characterize Postural Control in Standing Balance Tasks?

    Science.gov (United States)

    Caballero, Carla; Barbado, David; Moreno, Francisco Javier

    2015-01-01

    The authors' aim was to determine which variables allow for the characterization of motor balance behavior. Traditional measures and nonlinear measures of center of pressure (COP; n = 30) and kinematics (n = 10) were tested in their absolute and relative consistency in a 30-s standing balance task protocol under stable and unstable conditions. Regarding COP variables, mean velocity (mVel), permutation entropy (PE) and detrended fluctuation analysis (DFA) exhibited high consistency between trials and ranked individuals more accurately compare with other metrics. In the kinematic signal mVel, PE and DFA had good intrasession reliability values in unstable conditions. Overall, the intrasession reliability values were better in the unstable condition than in the stable condition and the measures calculated using derived data had better intrasession reliability values. In conclusion, mVel, PE, and DFA allow for the good characterization of motor balance behavior in a simplified protocol where velocity time series are analyzed.

  12. Carbon, nitrogen, C/N ratio and their stand heterogeneity in the soil of Norway spruce stands

    Directory of Open Access Journals (Sweden)

    Valerie Vranová

    2010-01-01

    Full Text Available This work is aimed to determine the effect of thinning of young spruce stands in Moravian-Silesian Beskids Mts. on concentrations and relative stand heterogeneity of Cox, Nt and C/N in soil. Concentrations of Cox and Nt were significantly higher in individual horizons of forest humus floor. The thinning did not influence significantly (P > 0.05 concentrations of Cox, Nt and C/N ratio in particular soil horizons, with the exception of C/N ration in E horizon. Relative stand heterogeneity of the studied soil properties was mostly higher in soil of dense forest stand. The values of relative stand heterogeneity for individual horizons ranged from 3.1 to 61.9 % in case of Cox, from 4.9 to 55.2 % for Nt and from 5.3 to 42.5 % for C/N ratio. Results of this work are useful to predict stand heterogeneity of soil biochemical properties which are known to correlate with especially Cox in soil on studied plots, especially soil respiration and enzymatic activities.

  13. Acoustic radiation force on a sphere in standing and quasi-standing zero-order Bessel beam tweezers

    International Nuclear Information System (INIS)

    Mitri, F.G.

    2008-01-01

    Starting from the exact acoustic scattering from a sphere immersed in an ideal fluid and centered along the propagation axis of a standing or quasi-standing zero-order Bessel beam, explicit partial-wave representations for the radiation force are derived. A standing or a quasi-standing acoustic field is the result of propagating two equal or unequal amplitude zero-order Bessel beams, respectively, along the same axis but in opposite sense. The Bessel beam is characterized by the half-cone angle β of its plane wave components, such that β = 0 represents a plane wave. It is assumed here that the half-cone angle β for each of the counter-propagating acoustic Bessel beams is equal. Fluid, elastic and viscoelastic spheres immersed in water are treated as examples. Results indicate the capability of manipulating spherical targets based on their mechanical and acoustical properties. This condition provides an impetus for further designing acoustic tweezers operating with standing or quasi-standing Bessel acoustic waves. Potential applications include particle manipulation in micro-fluidic lab-on-chips as well as in reduced gravity environments

  14. Ingestive behavior of Nellore steers in feedlot fed with diets containing different corn hybrids

    Directory of Open Access Journals (Sweden)

    Ivone Yurika Mizubuti

    2014-02-01

    Full Text Available The objective of this work was to study the feeding behavior of Nellore beef cattle in feedlot fed with diets containing different corn hybrids. Twenty-seven animals averaging 350 ± 24 kg of body weight and 24 months of age, were used. The animals were distributed in a completely randomized design with three treatments (T, where, T1-TDFC: total diet containing flint corn, T2-TDSFC: total diet containing semi-flint corn and T3-TDSDC: total diet containing semi-dent corn, with 9 replicates per treatment. The animals were fed ad libitum twice a day (at 8:00am and 4:00pm with a isocaloric and isonitrogenous diet, with 30% of sugar cane bagasse and 70% concentrate (88% maize, 8% soybean meal, 3% mineral and vitamin supplement and 1% urea for 95 days (14 days of adaptation and 3 experimental periods of 27 days each. The animals were weighed at the beginning of the experiment and after each period of 27 days, always in a fasting period of 16 hours. The evaluation of animals feeding behavior occurred at the last day of each period by visual observation every five minutes for full periods of 24 hours. Observations were made in four shifts: morning (06:00 to 12:00, afternoon (12:00 to 18:00, evening (18:00 to 00:00 and early morning (00:00 06:00 to determine the number of ruminal bolus, chewing time, total feeding time, total ruminating standing time, total ruminating lying time, total standing idle time and total lying idle time. During the night’s observations, the stalls received artificial illumination to facilitate the data collection and the animals were adapted with light at night for three days before observations. Animals fed with diets containing semi-dent corn had longer chew time and more ruminal bolus than those fed with flint corn, but did not differ from those that received semi-flint corn in the diet. The chewing time and number of ruminal bolus varied with the observation periods, being higher in the morning and decreasing in the

  15. 2015 Space Radiation Standing Review Panel

    Science.gov (United States)

    Steinberg, Susan

    2015-01-01

    The 2015 Space Radiation Standing Review Panel (from here on referred to as the SRP) met for a site visit in Houston, TX on December 8 - 9, 2015. The SRP met with representatives from the Space Radiation Element and members of the Human Research Program (HRP) to review the updated research plan for the Risk of Radiation Carcinogenesis Cancer Risk. The SRP also reviewed the newly revised Evidence Reports for the Risk of Acute Radiation Syndromes Due to Solar Particle Events (SPEs) (Acute Risk), the Risk of Acute (In-flight) and Late Central Nervous System Effects from Radiation Exposure (CNS Risk), and the Risk of Cardiovascular Disease and Other Degenerative Tissue Effects from Radiation (Degen Risk), as well as a status update on these Risks. The SRP would like to commend Dr. Simonsen, Dr. Huff, Dr. Nelson, and Dr. Patel for their detailed presentations. The Space Radiation Element did a great job presenting a very large volume of material. The SRP considers it to be a strong program that is well-organized, well-coordinated and generates valuable data. The SRP commended the tissue sharing protocols, working groups, systems biology analysis, and standardization of models. In several of the discussed areas the SRP suggested improvements of the research plans in the future. These include the following: It is important that the team has expanded efforts examining immunology and inflammation as important components of the space radiation biological response. This is an overarching and important focus that is likely to apply to all aspects of the program including acute, CVD, CNS, cancer and others. Given that the area of immunology/inflammation is highly complex (and especially so as it relates to radiation), it warrants the expansion of investigators expertise in immunology and inflammation to work with the individual research projects and also the NASA Specialized Center of Research (NSCORs). Historical data on radiation injury to be entered into the Watson

  16. Nuclear insulin-like growth factor 1 receptor phosphorylates proliferating cell nuclear antigen and rescues stalled replication forks after DNA damage.

    Science.gov (United States)

    Waraky, Ahmed; Lin, Yingbo; Warsito, Dudi; Haglund, Felix; Aleem, Eiman; Larsson, Olle

    2017-11-03

    We have previously shown that the insulin-like growth factor 1 receptor (IGF-1R) translocates to the cell nucleus, where it binds to enhancer-like regions and increases gene transcription. Further studies have demonstrated that nuclear IGF-1R (nIGF-1R) physically and functionally interacts with some nuclear proteins, i.e. the lymphoid enhancer-binding factor 1 (Lef1), histone H3, and Brahma-related gene-1 proteins. In this study, we identified the proliferating cell nuclear antigen (PCNA) as a nIGF-1R-binding partner. PCNA is a pivotal component of the replication fork machinery and a main regulator of the DNA damage tolerance (DDT) pathway. We found that IGF-1R interacts with and phosphorylates PCNA in human embryonic stem cells and other cell lines. In vitro MS analysis of PCNA co-incubated with the IGF-1R kinase indicated tyrosine residues 60, 133, and 250 in PCNA as IGF-1R targets, and PCNA phosphorylation was followed by mono- and polyubiquitination. Co-immunoprecipitation experiments suggested that these ubiquitination events may be mediated by DDT-dependent E2/E3 ligases ( e.g. RAD18 and SHPRH/HLTF). Absence of IGF-1R or mutation of Tyr-60, Tyr-133, or Tyr-250 in PCNA abrogated its ubiquitination. Unlike in cells expressing IGF-1R, externally induced DNA damage in IGF-1R-negative cells caused G 1 cell cycle arrest and S phase fork stalling. Taken together, our results suggest a role of IGF-1R in DDT. © 2017 by The American Society for Biochemistry and Molecular Biology, Inc.

  17. Study of the stall delay phenomenon and of wind turbine blade dynamics using numerical approaches and NREL's wind tunnel tests

    Energy Technology Data Exchange (ETDEWEB)

    Breton, Simon-Philippe

    2008-06-15

    The production of electricity from wind has experienced an enormous growth worldwide in the last 20 years. It is now widely seen as a serious alternative to more conventional energy production methods. Improvements are however still possible to make it more cost-effective. This can be done through a better understanding of the fundamental phenomena involved in the interaction of the wind with the wind turbine rotor. This growth in the production of energy from wind is expected to continue at a similar rate in the years to come, helped by the installation of wind turbines at sea, that is becoming a hot topic in the wind energy field today. The phenomenon of stall delay affecting rotating wind turbine blades is an example of an aerodynamic phenomenon that is not yet fully understood. Several models exist to correct for this effect. Five such models were first tested within a vortex wake simulation code based on the modelling of a prescribed wake behind the rotor of the turbine. Comparison was made with wind tunnel test data acquired in head-on flow on a two-bladed 10.1 diameter wind turbine at the National Renewable Energy Laboratories (NREL) in 2000. It revealed a general overprediction of the stall delay effects, at the same time as great disparity was obtained between the different models. Conclusions from this work served as a starting point for a much more thorough investigation on this subject, where several models were tested in terms of different quantities using the same simulation code, and where the application of some of the models was improved. Overprediction of the loads was once again obtained when comparison was made to the NREL results in head-on flow, and none of the models was found to correctly represent the flow physics involved. The premises on which each of the models relies were discussed as a means of better understanding and modelling this phenomenon. The important issue of tip loss was also covered, and guidelines were suggested to improve

  18. Stand diameter distribution modelling and prediction based on Richards function.

    Directory of Open Access Journals (Sweden)

    Ai-guo Duan

    Full Text Available The objective of this study was to introduce application of the Richards equation on modelling and prediction of stand diameter distribution. The long-term repeated measurement data sets, consisted of 309 diameter frequency distributions from Chinese fir (Cunninghamia lanceolata plantations in the southern China, were used. Also, 150 stands were used as fitting data, the other 159 stands were used for testing. Nonlinear regression method (NRM or maximum likelihood estimates method (MLEM were applied to estimate the parameters of models, and the parameter prediction method (PPM and parameter recovery method (PRM were used to predict the diameter distributions of unknown stands. Four main conclusions were obtained: (1 R distribution presented a more accurate simulation than three-parametric Weibull function; (2 the parameters p, q and r of R distribution proved to be its scale, location and shape parameters, and have a deep relationship with stand characteristics, which means the parameters of R distribution have good theoretical interpretation; (3 the ordinate of inflection point of R distribution has significant relativity with its skewness and kurtosis, and the fitted main distribution range for the cumulative diameter distribution of Chinese fir plantations was 0.4∼0.6; (4 the goodness-of-fit test showed diameter distributions of unknown stands can be well estimated by applying R distribution based on PRM or the combination of PPM and PRM under the condition that only quadratic mean DBH or plus stand age are known, and the non-rejection rates were near 80%, which are higher than the 72.33% non-rejection rate of three-parametric Weibull function based on the combination of PPM and PRM.

  19. Construction Progress of S-IC Test Stand Towers

    Science.gov (United States)

    1963-01-01

    At its founding, the Marshall Space Flight Center (MSFC) inherited the Army's Jupiter and Redstone test stands, but much larger facilities were needed for the giant stages of the Saturn V. From 1960 to 1964, the existing stands were remodeled and a sizable new test area was developed. The new comprehensive test complex for propulsion and structural dynamics was unique within the nation and the free world, and they remain so today because they were constructed with foresight to meet the future as well as on going needs. Construction of the S-IC Static test stand complex began in 1961 in the west test area of MSFC, and was completed in 1964. The S-IC static test stand was designed to develop and test the 138-ft long and 33-ft diameter Saturn V S-IC first stage, or booster stage, weighing in at 280,000 pounds. Required to hold down the brute force of a 7,500,000-pound thrust produced by 5 F-1 engines, the S-IC static test stand was designed and constructed with the strength of hundreds of tons of steel and 12,000,000 pounds of cement, planted down to bedrock 40 feet below ground level. The foundation walls, constructed with concrete and steel, are 4 feet thick. The base structure consists of four towers with 40-foot-thick walls extending upward 144 feet above ground level. The structure was topped by a crane with a 135-foot boom. With the boom in the upright position, the stand was given an overall height of 405 feet, placing it among the highest structures in Alabama at the time. This photograph taken April 17, 1963, gives a look at the four tower legs of the S-IC test stand at their completed height.

  20. Construction Progress of the S-IC Test Stand Tower

    Science.gov (United States)

    1963-01-01

    At its founding, the Marshall Space Flight Center (MSFC) inherited the Army's Jupiter and Redstone test stands, but much larger facilities were needed for the giant stages of the Saturn V. From 1960 to 1964, the existing stands were remodeled and a sizable new test area was developed. The new comprehensive test complex for propulsion and structural dynamics was unique within the nation and the free world, and they remain so today because they were constructed with foresight to meet the future as well as on going needs. Construction of the S-IC Static test stand complex began in 1961 in the west test area of MSFC, and was completed in 1964. The S-IC static test stand was designed to develop and test the 138-ft long and 33-ft diameter Saturn V S-IC first stage, or booster stage, weighing in at 280,000 pounds. Required to hold down the brute force of a 7,500,000-pound thrust produced by 5 F-1 engines, the S-IC static test stand was designed and constructed with the strength of hundreds of tons of steel and 12,000,000 pounds of cement, planted down to bedrock 40 feet below ground level. The foundation walls, constructed with concrete and steel, are 4 feet thick. The base structure consists of four towers with 40-foot-thick walls extending upward 144 feet above ground level. The structure was topped by a crane with a 135-foot boom. With the boom in the upright position, the stand was given an overall height of 405 feet, placing it among the highest structures in Alabama at the time. This photograph, taken from ground level on May 7, 1963, gives a close look at one of the four towers legs of the S-IC test stand nearing its completed height.

  1. Construction Progress of the S-IC Test Stand

    Science.gov (United States)

    1963-01-01

    At its founding, the Marshall Space Flight Center (MSFC) inherited the Army's Jupiter and Redstone test stands, but much larger facilities were needed for the giant stages of the Saturn V. From 1960 to 1964, the existing stands were remodeled and a sizable new test area was developed. The new comprehensive test complex for propulsion and structural dynamics was unique within the nation and the free world, and they remain so today because they were constructed with foresight to meet the future as well as on going needs. Construction of the S-IC Static test stand complex began in 1961 in the west test area of MSFC, and was completed in 1964. The S-IC static test stand was designed to develop and test the 138-ft long and 33-ft diameter Saturn V S-IC first stage, or booster stage, weighing in at 280,000 pounds. Required to hold down the brute force of a 7,500,000-pound thrust produced by 5 F-1 engines, the S-IC static test stand was designed and constructed with the strength of hundreds of tons of steel and 12,000,000 pounds of cement, planted down to bedrock 40 feet below ground level. The foundation walls, constructed with concrete and steel, are 4 feet thick. The base structure consists of four towers with 40-foot-thick walls extending upward 144 feet above ground level. The structure was topped by a crane with a 135-foot boom. With the boom in the upright position, the stand was given an overall height of 405 feet, placing it among the highest structures in Alabama at the time. This photo shows the progress of the S-IC test stand as of November 20, 1963.

  2. Construction Progress of the S-IC Test Stand Towers

    Science.gov (United States)

    1963-01-01

    At its founding, the Marshall Space Flight Center (MSFC) inherited the Army's Jupiter and Redstone test stands, but much larger facilities were needed for the giant stages of the Saturn V. From 1960 to 1964, the existing stands were remodeled and a sizable new test area was developed. The new comprehensive test complex for propulsion and structural dynamics was unique within the nation and the free world, and they remain so today because they were constructed with foresight to meet the future as well as on going needs. Construction of the S-IC Static test stand complex began in 1961 in the west test area of MSFC, and was completed in 1964. The S-IC static test stand was designed to develop and test the 138-ft long and 33-ft diameter Saturn V S-IC first stage, or booster stage, weighing in at 280,000 pounds. Required to hold down the brute force of a 7,500,000-pound thrust produced by 5 F-1 engines, the S-IC static test stand was designed and constructed with the strength of hundreds of tons of steel and 12,000,000 pounds of cement, planted down to bedrock 40 feet below ground level. The foundation walls, constructed with concrete and steel, are 4 feet thick. The base structure consists of four towers with 40-foot-thick walls extending upward 144 feet above ground level. The structure was topped by a crane with a 135-foot boom. With the boom in the upright position, the stand was given an overall height of 405 feet, placing it among the highest structures in Alabama at the time. This photograph, taken April 4, 1963, gives a close up look at the ever-growing four towers of the S-IC Test Stand.

  3. Post-breeding bird responses to canopy tree retention, stand size, and edge in regenerating Appalachian hardwood stands

    Science.gov (United States)

    McDermott, M.E.; Wood, P.B.

    2011-01-01

    Avian use of even-aged timber harvests is likely affected by stand attributes such as size, amount of edge, and retained basal area, all characteristics that can easily be manipulated in timber harvesting plans. However, few studies have examined their effects during the post-breeding period. We studied the impacts of clearcut, low-leave two-age, and high-leave two-age harvesting on post-breeding birds using transect sampling and mist-netting in north-central West Virginia. In our approach, we studied the effects of these harvest types as well as stand size and edge on species characteristic of both early-successional and mature forest habitats. In 2005-2006, 13 stands ranging from 4 to 10. years post-harvest and 4-21. ha in size were sampled from late June through mid-August. Capture rates and relative abundance were similar among treatments for generalist birds. Early-successional birds had the lowest capture rates and fewer species (~30% lower), and late-successional birds reached their highest abundance and species totals (double the other treatments) in high-leave two-age stands. Area sensitivity was evident for all breeding habitat groups. Both generalist and late-successional bird captures were negatively related to stand size, but these groups showed no clear edge effects. Mean relative abundance decreased to nearly zero for the latter group in the largest stands. In contrast, early-successional species tended to use stand interiors more often and responded positively to stand size. Capture rates for this group tripled as stand size increased from 4 to 21. ha. Few birds in the forest periphery responded to harvest edge types despite within-stand edge effects evident for several species. To create suitable habitat for early-successional birds, large, non-linear openings with a low retained basal area are ideal, while smaller harvests and increased residual tree retention would provide habitat for more late-successional birds post-breeding. Although our study

  4. The global coherence initiative: creating a coherent planetary standing wave.

    Science.gov (United States)

    McCraty, Rollin; Deyhle, Annette; Childre, Doc

    2012-03-01

    The much anticipated year of 2012 is now here. Amidst the predictions and cosmic alignments that many are aware of, one thing is for sure: it will be an interesting and exciting year as the speed of change continues to increase, bringing both chaos and great opportunity. One benchmark of these times is a shift in many people from a paradigm of competition to one of greater cooperation. All across the planet, increasing numbers of people are practicing heart-based living, and more groups are forming activities that support positive change and creative solutions for manifesting a better world. The Global Coherence Initiative (GCI) is a science-based, co-creative project to unite people in heart-focused care and intention. GCI is working in concert with other initiatives to realize the increased power of collective intention and consciousness. The convergence of several independent lines of evidence provides strong support for the existence of a global information field that connects all living systems and consciousness. Every cell in our bodies is bathed in an external and internal environment of fluctuating invisible magnetic forces that can affect virtually every cell and circuit in biological systems. Therefore, it should not be surprising that numerous physiological rhythms in humans and global collective behaviors are not only synchronized with solar and geomagnetic activity, but disruptions in these fields can create adverse effects on human health and behavior. The most likely mechanism for explaining how solar and geomagnetic influences affect human health and behavior are a coupling between the human nervous system and resonating geomagnetic frequencies, called Schumann resonances, which occur in the earth-ionosphere resonant cavity and Alfvén waves. It is well established that these resonant frequencies directly overlap with those of the human brain and cardiovascular system. If all living systems are indeed interconnected and communicate with each other

  5. Construction Progress S-IC Test Stand Block House Interior

    Science.gov (United States)

    1963-01-01

    At its founding, the Marshall Space Flight Center (MSFC) inherited the Army's Jupiter and Redstone test stands, but much larger facilities were needed for the giant stages of the Saturn V. From 1960 to 1964, the existing stands were remodeled and a sizable new test area was developed. The new comprehensive test complex for propulsion and structural dynamics was unique within the nation and the free world, and they remain so today because they were constructed with foresight to meet the future as well as on going needs. Construction of the S-IC Static test stand complex began in 1961 in the west test area of MSFC, and was completed in 1964. The S-IC static test stand was designed to develop and test the 138-ft long and 33-ft diameter Saturn V S-IC first stage, or booster stage, weighing in at 280,000 pounds. Required to hold down the brute force of a 7,500,000-pound thrust produced by 5 F-1 engines, the S-IC static test stand was designed and constructed with the strength of hundreds of tons of steel and 12,000,000 pounds of cement, planted down to bedrock 40 feet below ground level. The foundation walls, constructed with concrete and steel, are 4 feet thick. The base structure consists of four towers with 40-foot-thick walls extending upward 144 feet above ground level. The structure was topped by a crane with a 135-foot boom. With the boom in the upright position, the stand was given an overall height of 405 feet, placing it among the highest structures in Alabama at the time. In addition to the stand itself, related facilities were constructed during this time. Built directly east of the test stand was the Block House, which served as the control center for the test stand. The two were connected by a narrow access tunnel which housed the cables for the controls. This photograph, taken August 12, 1963, offers a view of the Block House interior.

  6. Construction Progress of S-IC Test Stand Pump House

    Science.gov (United States)

    1963-01-01

    At its founding, the Marshall Space Flight Center (MSFC) inherited the Army's Jupiter and Redstone test stands, but much larger facilities were needed for the giant stages of the Saturn V. From 1960 to 1964, the existing stands were remodeled and a sizable new test area was developed. The new comprehensive test complex for propulsion and structural dynamics was unique within the nation and the free world, and they remain so today because they were constructed with foresight to meet the future as well as on going needs. Construction of the S-IC Static test stand complex began in 1961 in the west test area of MSFC, and was completed in 1964. The S-IC static test stand was designed to develop and test the 138-ft long and 33-ft diameter Saturn V S-IC first stage, or booster stage, weighing in at 280,000 pounds. Required to hold down the brute force of a 7,500,000-pound thrust produced by 5 F-1 engines, the S-IC static test stand was designed and constructed with the strength of hundreds of tons of steel and 12,000,000 pounds of cement, planted down to bedrock 40 feet below ground level. The foundation walls, constructed with concrete and steel, are 4 feet thick. The base structure consists of four towers with 40-foot-thick walls extending upward 144 feet above ground level. The structure was topped by a crane with a 135-foot boom. With the boom in the upright position, the stand was given an overall height of 405 feet, placing it among the highest structures in Alabama at the time. In addition to the stand itself, related facilities were constructed during this time. Built to the northeast east was a newly constructed Pump House. Its function was to provide water to the stand to prevent melting damage during testing. The water was sprayed through small holes in the stand's 1900 ton flame deflector at the rate of 320,000 gallons per minute. This photograph of the Pump House area was taken August 13, 1963. The massive round water storage tanks can be seen to the left of

  7. Uprising: An examination of sit-stand workstations, mental health and work ability in sedentary office workers, in Western Australia.

    Science.gov (United States)

    Tobin, Rochelle; Leavy, Justine; Jancey, Jonine

    2016-10-17

    Office-based staff spend around three quarters of their work day sitting. People who sit for long periods while at work are at greater risk of adverse health outcomes. The pilot study aimed to determine the effect of sit-stand workstations on office-based staff sedentary and physical activity behaviors, work ability and self-reported physical and mental health outcomes. A two-group pre-post study design assessed changes in sedentary and physical activity behaviors (time spent sitting, standing and stepping and sit-stand transitions and number of steps taken) work ability and physical and mental health. Physical activity behaviors were measured using activPAL activity monitors and self-reported data on work ability and physical and mental health were collected using an online questionnaire. Relative to the controls (n=19), the intervention group (n=18) significantly decreased time spent sitting by 100 minutes (pwork ability when compared to lifetime best (p=0.008). There were no significant differences for all other sedentary behavior, other workability outcomes, physical health or mental health outcomes at follow-up. The Uprising Study found that sit-stand workstations are an effective strategy to reduce occupational sitting time in office-based workers over a one month period.

  8. One- or Two-Legged Standing: What Is the More Suitable Protocol to Assess the Postural Effects of the Rigid Ankle Orthosis?

    Science.gov (United States)

    Rougier, Patrice; Genthon, Nicolas; Gallois-Montbrun, Thibault; Brugiere, Steve; Bouvat, Eric

    2009-01-01

    To highlight the capacity of one- and two-legged standing protocols when assessing postural behavior induced by a rigid ankle orthosis, 14 healthy individuals stood upright barefoot and wore either an elastic stocking on the preferred leg or a rigid orthosis with or without additional taping in one- or two-legged (TL) conditions. Traditional…

  9. [Soil quality assessment of forest stand in different plantation esosystems].

    Science.gov (United States)

    Huang, Yu; Wang, Silong; Feng, Zongwei; Gao, Hong; Wang, Qingkui; Hu, Yalin; Yan, Shaokui

    2004-12-01

    After a clear-cutting of the first generation Cunninghamia lanceolata plantation in 1982, three plantation ecosystems, pure Michelia macclurei stand (PMS), pure Chinese-fir stand (PCS) and their mixed stand, were established in spring 1983, and their effects on soil characteristics were evaluated by measuring some soil physical, chemical, microbiological and biochemical parameters. After 20 years' plantation, all test indices showed differences among different forest management models. Both PMS and MCM had a favorable effect on soil fertility maintenance. Soil quality assessment showed that some soil functions, e.g., water availability, nutrient availability, root suitability and soil quality index were all in a moderate level under the mixed and pure PMS stands, whereas in a relatively lower level under successive PCS stand. The results also showed that there existed close correlations between soil total organic C (TOC), cation exchange capacity (CEC), microbial biomass-C (Cmic) and other soil physical, chemical and biological indices. Therefore, TOC, CEC and Cmic could be used as the indicators in assessing soil quality in this study area. In addition, there were also positive correlations between soil microbial biomass-C and TOC, soil microbial biomass-N and total N, and soil microbial biomass-P and total P in the present study.

  10. Taxa de gestação em fêmeas da raça Holandesa confinadas em free stall, no verão e inverno Gestation rate of Holstein females confined in free stall, during the summer and winter

    Directory of Open Access Journals (Sweden)

    M.F.A. Pires

    2002-02-01

    Full Text Available A taxa de gestação de vacas em lactação e de novilhas confinadas em free stall foi avaliada durante o inverno e o verão, nos anos de 1993, 1994 e 1995. A temperatura ambiente (TA e a umidade relativa do ar (UR foram acompanhadas diariamente, durante quatro meses de verão (dezembro a março e três meses de inverno (junho a agosto. Em cada estação mediram-se semanalmente às 9, 15 e 21h a temperatura retal (TR e a freqüência respiratória (FR de 50% das vacas em lactação, sorteadas ao acaso, separadas em quatro grupos de acordo com a produção de leite. A TA e o índice de temperatura e umidade (ITU médios foram mais elevados (P The gestation rate was used to evaluate the reproductive performance of dairy cows and heifers confined in a free stall barn during the winter and summer seasons of 1993, 1994 and 1995. The temperature (T and relative humidity (RH were monitored daily during the summer (December, January, February and March and winter (June, July and August. The rectal temperature (RT and respiration rate (RR were measured weekly at 9AM and 3 and 9PM, in each season, in 50% of the animals randomly selected and sorted in four groups based on their milk production. The averages of T and the temperature and humidity index (THI were higher in the summer (25.6ºC e 75.8 than in the winter (19.0ºC e 65.3, while the RH were the same in both seasons (80.0%. The averages of RT and RR were always higher in the summer and at 3PM when compared to 9AM RT and RR (39.47ºC and 64.76 mov/min vs 38.89ºC and 44.21 mov/min. Gestation rate for milking cows was smaller in summer than in the winter. Conversely 85.4% of heifers became pregnant during the summer and 78.5% during the winter season.

  11. Custo e resultados do tratamento de seqüelas de laminite bovina: relato de 112 casos em vacas em lactação no sistema free-stall Results and costs of treatment for bovine laminitis sequelae: study of 112 lameness cases in lactating cows in free-stall system

    Directory of Open Access Journals (Sweden)

    P.M. Ferreira

    2004-10-01

    Full Text Available Os resultados e o custo do tratamento de seqüelas podais da laminite subclínica são descritos em 112 casos de manqueira em vacas em lactação mantidas no sistema free-stall. As observações feitas durante um ano abrangeram animais de 2,5 a 10 anos de idade, da primeira à sexta lactação e com média de produção de 8.000±2.000kg de leite. O protocolo de tratamento, descrito detalhadamente para cada uma das afecções podais, foi eficiente na reversão de todas elas. O custo total do tratamento para o rebanho foi de US$5,005.23, equivalente ao custo médio de US$44.68 por animal. O tratamento das úlceras de sola foi o mais dispendioso (US$72.58 e o mais demorado (26,8 dias. As afecções mais comuns foram os abscessos de sola e do talão e as lesões da linha branca (64/112 ou 57,2%.The results and costs of treatments of feet sequelae of subclinic dairy cattle laminitis were described in 112 cases of lameness in lactating cows maintained in free stall system. The analyses were performed in an one-year-period using 2.5 to 10 year-old, first to sixth parity cows. Average milk yield was 8,000±2,000kg. The treatment protocol was described in details for each digit lesion and it was very successful to reverse all kinds of lesions. The total treatment cost for the herd was US$5,005.23 and the mean cost/animal was US$44.68. The ulcer treatments were costly (US$72.58 and longer (26.8 days. Sole and heel abscesses and white line disease at the foe (64/112 or 57.2% were most commonly observed.

  12. A Standing-Wave Experiment with a Guitar

    Science.gov (United States)

    Inman, Fred W.

    2006-10-01

    When teaching standing waves, one often uses as examples musical instruments with strings, e.g., pianos, violins, and guitars. In today's popular music culture, young people may be more familiar with guitars than any other string instrument. I was helping my 15-year-old granddaughter make some repairs and adjustments to her electric guitar, and the subject of the spacing between the frets on the fingerboard was raised. I told her that the physics of standing waves and the equal tempered musical scale dictate the location of the frets. The purpose of this paper is to suggest that students might be introduced to the physics of standing waves using a guitar and to the formula for the fret locations. By measuring the positions of the frets, this formula can be tested.

  13. Standing phase angle reduction for power system restoration

    Energy Technology Data Exchange (ETDEWEB)

    Hazarika, D. [Assam Engineering College (India). Electrical Engineering Dept.; Sinha, A.K. [IIT Khargpur (India). Electrical Engineering Dept.

    1998-01-01

    The paper describes a methodology for the reduction of standing phase angle (SPA) difference between two buses of a power system, which is essential before interconnecting a line between two buses. This problem is encountered normally during restoration operations of a power system. For this purpose, the standing phase angle difference between two specific buses is represented in terms of sensitivity factors associated with the change in real power injections at the buses. To arrive at the desired standing phase angle difference between two buses, the modified contribution at generation/load buses have been evaluated based on 'higher the sensitivity higher the participation' logic. This methodology acts as a direct help to reduce excessive SPA difference between two buses to an acceptable limit, which otherwise requires regulation of various generation levels on a trial and error basis. (author)

  14. Performing Arabness in Arab American Stand-up Comedy

    Directory of Open Access Journals (Sweden)

    Fouad Selim Yasser

    2014-12-01

    Full Text Available This article deals with the dramatic art of stand-up comedy. It locates Arab American stand-up comedy within a broader American humorous tradition and investigates the way Arab American performers use this art to negotiate and (reconstruct their identity. The main question in this article is the way Arab American stand-up comedians define their relationship to the Arab and the western worlds in the process of establishing their Arab American identity. Three humor theories - the relief theory, the incongruity theory, and the superiority theory - are deployed in the study to examine the representation of Arabness in selected Arab American performances. The study argues that Arab American comics minstrelize their own diasporic origin through reinscribing a range of orientalizing practices in order to claim their Americanness.

  15. Influence of noise on decay predictions in standing trees

    Science.gov (United States)

    Visalga, G.; Rupšys, P.; Petrauskas, E.

    2017-10-01

    In the present study, the stochastic process, termed the Vasicek, have been implemented to analyze propagation velocity data of stress wave that diffuses through the wood of decayed and sound stems in standing trees. Stochastic processes offer the possibility of capturing important distributional differences between stress wave velocity datasets of decayed and sound trees and make the detecting rule flexible to internal decay in standing trees. It is shown that the Vasicek type stochastic process is a possible candidate for statistical classification of waveforms. Rigorous quantile regression analysis is based on the conditional probability density functions whose are fitted for stress wave velocity datasets of sound and decayed trees. New developed detector rules derived from stochastic differential equations may be used as an initial tool for detecting internal decay in standing trees.

  16. Stand tending and root rot in Norway spruce stands - economical effects caused by root rot at different thinning regimes

    International Nuclear Information System (INIS)

    Johansson, Mats

    1997-01-01

    This report is divided into three parts: 1) a literature study describing the most common fungi causing rot in wood and descriptions of various strategies to reduce economic loss from root rot, 2) a check of a model describing the development of butt rot in pure Norway spruce plantations in southern Sweden, and 3) simulated economic effects of root rot in stands with various stand tending. The rot model was used to estimate future rot frequencies in the economic calculations. In order to avoid overestimations of rot frequencies, the calculations were also executed when assuming slower growth of rot than shown in the model. When analysing the economical effects of rot, the following three thinning programmes were used: Program 1: thinning at the ages of 30- and 45 years. Final felling at the ages 50-, 55-, 60-, 65-, and 70 years. Program 2: thinning at the ages of 40- and 60- years. Final felling at the ages 65 and 75 years. Program 3: thinning at the ages of 30-, 40-, 55-, and 70 years. Final felling at the ages 80 and 90 years. With an interest rate of 3%, programme 2 (final felling at the age of 65 years) had the highest value at present. This result was valid when presuming butt rot in the stand as well as when presuming no butt rot in the stand. There was a small difference between the value at present in programme 1 (final felling at the age of 60 years) and in programme 3 (final felling at the age of 80 years). When presuming butt rot in the stand, the value at present in programme 3 decreased somewhat more in comparison to the value at present in programme 1. Compared to no butt rot in the stand, the optimal final felling time appeared five to ten years earlier when assuming butt rot in the stand. Stand tending programme 1 and an interest rate of 3% were used. Interest rates 2 and 4% did not indicate shorter rotation. The calculated optimal time of final felling appeared at the same stand age whether assuming rot preset or not. The results in this study

  17. Stand quality management of a water oak plantation in Louisiana: preliminary results following thinning

    Science.gov (United States)

    James S. Meadows; Daniel A., Jr. Skojac

    2010-01-01

    Stand quality management is a new guiding principle in which thinning prescriptions are based on tree quality rather than on residual stand density. We recently initiated a series of hardwood thinning studies to determine the effects of four stand quality management thinning prescriptions on both stand-level and individual-tree-level growth, quality, and value: (1) no...

  18. Maximum stand density for ponderosa pine and red and white fir in northern California

    Science.gov (United States)

    William.W. Oliver; Fabian C.C. Uzoh

    1997-01-01

    Why are forest managers interested in quantifying maximum stand density? Nearly all conceivable management objectives dictate a stand density less than a biological maximum. Certainly, the notion that thinning dense stands increases growth on the remaining trees and reduces mortality is well-established in the literature. The interest in quantifying maximum stand...

  19. Spatial Interactions in Multiple-Use Forestry and Substitution and Wealth Effects for the Single Stand

    Science.gov (United States)

    Stephen K. Swallow; David N. Wear

    1993-01-01

    Forestry models often ignore spatial relationships between forest stands. This paper isolates the effects of stand interactions in muitiple-use forestry through a straightforward extension of the single-stand model. Effects of stand interactions decompose into wealth and substitution effects and may cause time-varying patterns of resource use for a forest...

  20. Models for a stand-alone PV system

    DEFF Research Database (Denmark)

    Hansen, A.D.; Sørensen, Poul Ejnar; Hansen, L.H.

    2001-01-01

    This report presents a number of models for modelling and simulation of a stand-alone photovoltaic (PV) system with a battery bank verified against a system installed at Risø National Laboratory. The work has been supported by the Danish Ministry ofEnergy, as a part of the activities in the Solar...... Energy Centre Denmark. The study is carried out at Risø National Laboratory with the main purpose to establish a library of simple mathematical models for each individual element of a stand-alone PVsystem, namely solar cells, battery, controller, inverter and load. The models for PV module and battery...

  1. Bilateral Posterior Native Hip Dislocations after Fall from Standing

    Directory of Open Access Journals (Sweden)

    Jane Xiao

    2017-10-01

    Full Text Available We present a case of bilateral posterior native hip dislocations after a fall from standing. This exceedingly rare diagnosis is classically associated with younger patients whose bones are strong enough to dislocate rather than fracture in the setting of a high-momentum collision. We present an unusual case of an 88-year-old male with native hips who sustained a low-energy collision after falling from standing and was found to have bilateral posterior hip dislocations without associated pelvis or femur fractures.

  2. Racial Issues in American Stand-up Comedy

    OpenAIRE

    Alina BOGDAN

    2014-01-01

    Stand-up comedy emerged in the late 1970s when the first live shows of this type were introduced to the public. This type of humour, which relies on ingenuity, contains a variety of topics used by comedians, such as their everyday life, religion, politics or racism. These are just a few of the topics usually employed in order to create comedy. It is curious how a serious matter such as racism, for example, can be used to trigger laughter. Eddie Griffin, an African American stand-up comedia...

  3. Gender-based differences in the cardiovascular response to standing

    Science.gov (United States)

    Gotshall, Robert W.; Tsai, Pai-Feng; Frey, Mary A. B.

    1991-01-01

    The cardiovascular responses of men and women to the stand test were compared by measuring respective values for heart rate, blood pressure, stroke volume, cardiac output, and total peripheral resistance during a 5-min supine and a 5-min standing test in ten subjects of each gender. It was found that, while the male and female subjects had similar heart rate values, all other responses exhibited greater changes in men than in women. While differences in the height of the subjects did not account for differences in cardiovascular responses, no mechanism responsible for these differences could be identified.

  4. Data acquisition system for PLT Neutral Beam Test Stand

    International Nuclear Information System (INIS)

    Francis, J.E. Jr.; Hammons, C.E.

    1977-01-01

    The PLT Neutral Beam Test Stand at Oak Ridge National Laboratory was constructed to test and condition powerful neutral beam sources for the Princeton Large Torus experiment at Princeton Plasma Physics Laboratory. The data acquisition system for the test stand monitors the beam characteristics and power output to determine if the beam is operating at its design specifications. The high speed of the computer system is utilized to provide near-real-time analysis of experimental data. The analysis of the data is presented as numerical tabulation and graphic display

  5. A FEW CONSIDERATIONS ABOUT TRADE FAIR STANDS DESIGN

    Directory of Open Access Journals (Sweden)

    NEIDONI Nadina

    2017-05-01

    Full Text Available The paper presents some aspects related to the design of a trade fair stand, advertising a company specialized in the fabrication of corrugated fibre board packaging. The first section reviews shortly the main features of the industrial design. The second section deals with the structural conception of successful trade shows. Further, the importance of the package in the marketing matters is addressed. In this context corrugated fibreboard, as secondary or tertiary material is essential. In the final section, a comparison between two trade fair stands, representing a corrugated fibreboard company are presented.

  6. Electron-phonon coupling in quasi free-standing graphene

    DEFF Research Database (Denmark)

    Christian Johannsen, Jens; Ulstrup, Søren; Bianchi, Marco

    2013-01-01

    Quasi free-standing monolayer graphene can be produced by intercalating species like oxygen or hydrogen between epitaxial graphene and the substrate crystal. If the graphene is indeed decoupled from the substrate, one would expect the observation of a similar electronic dispersion and many......-body effects, irrespective of the substrate and the material used to achieve the decoupling. Here we investigate the electron-phonon coupling in two different types of quasi free-standing monolayer graphene: decoupled from SiC via hydrogen intercalation and decoupled from Ir via oxygen intercalation. Both...

  7. Sources of nitrous oxide and other climate relevant gases on surface area in a dairy free stall barn with solid floor and outside slurry storage

    Science.gov (United States)

    Schmithausen, Alexander J.; Trimborn, Manfred; Büscher, Wolfgang

    2018-04-01

    Livestock production systems in agriculture are one of the major emitters of greenhouse gases. So far, the focus of research in the dairy farm sector was primarily on ruminal methane (CH4) emissions. Emissions of nitrous oxide (N2O) usually arise from solid manure or in deep litter free stall barns. Release of N2O occurs as a result of interactions between organic material, nitrogen and moisture. Data of N2O emissions from modern dairy barns and liquid manure management systems are rare. Thus, the goal of this research was to determine the main sources of trace gas emissions at the dairy farm level, including N2O. Areas such as the scraped surface area where dry and wet conditions alternate are interesting. Possible sources of trace gases within and outside the barn were localised by measuring trace gas concentration rates from different dairy farm areas (e.g., areas covered with urine and excrement or slurry storage system) via the closed chamber technique. The results indicate typical emission ratios of carbon dioxide (CO2), CH4 and N2O in the various areas to generate comparable equivalent values. Calculated on the basis of nitrogen excretion from dairy cows, total emissions of N2O were much lower from barns than typically measured in fields. However, there were also areas within the barn with individual events and unexpected release factors of N2O concentrations such as urine patches, polluted areas and cubicles. Emission factors of N2O ranged from 1.1 to 5.0 mg m-2 d-1, respectively, for cleaned areas and urine patches. By considering the release factors of these areas and their proportion of the entire barn, total emission rates of 371 CO2-eq. LU-1 a-1, 36 CO2-eq. LU-1 a-1, and 1.7 kg CO2-eq. LU-1 a-1 for CO2, CH4 and N2O, respectively, were measured for the whole barn surface area. The CH4 emissions from surface area were stronger climate relevant comparing to N2O emissions, but compared to CH4 emissions from slurry storage or ruminal fermentation (not

  8. To what extent is a breed-specific database necessary to differentiate meat from pasture-fed and stall-fed lambs using visible spectroscopy?

    Science.gov (United States)

    Prache, S; Huang, Y; Andueza, D

    2017-12-22

    Carotenoid pigments signature in the fat using visible reflectance spectroscopy has shown high potential for distinguishing pasture-fed (P) from stall concentrate-fed (S) lamb carcasses. However, a recent study demonstrated a between-breed variability in the digestive and metabolic fate of carotenoids pigments. The present study was therefore designed to investigate the extent to which this between-breed variability may affect the reliability of diet authentication using visible spectroscopy of the fat. We used 1054 male lambs from three breeds (Romane (ROM), Ile-de-France (OIF) and Limousine (LIM)). The breed-feed breakdown was 148 P and 258 S ROM, 102 P and 92 S OIF and 168 P and 286 S LIM lambs. The reflectance spectrum of perirenal fat was measured at 24 h postmortem at wavelengths between 400 and 700 nm. We quantified light absorption in the 450 to 510 nm area by calculating a traceability index (AVMI 450 to 510) considered as an indicator of the carotenoid concentration in the fat (method 1) and we performed a multivariate analysis over the full set of reflectance data between 400 and 700 nm (method 2). The reliability of method 1 proved very variable across breeds, with a percentage of correctly classified lambs reaching 95.3%, 90.5% and 79.4% in ROM, LIM and OIF lambs, respectively. Despite these between-breeds differences, the threshold of the linear discriminant analysis performed on AVMI 450 to 510 was fairly similar between breeds; when all the data for the three breeds were pooled, the threshold cut-off value was 224 units and the method correctly classified 90.2% of the 1054 lambs. Using the full range of reflectance data (method 2) enabled to significantly increase the proportion of correctly classified lambs for both OIF and LIM breeds, but not for ROM breed. It enabled to correctly classify 96.1%, 94.5% and 94.8% of the ROM, LIM and OIF lambs. The reliability of the discrimination was not significantly different when pooling all lambs for the three

  9. Stalled ERP at Random Textiles

    Science.gov (United States)

    Brumberg, Robert; Kops, Eric; Little, Elizabeth; Gamble, George; Underbakke, Jesse; Havelka, Douglas

    2016-01-01

    Andre Raymond, Executive Vice President of Sales and Marketing for Random Textiles Co. Inc. (RTC), stood in front of the podium to address his team of 70 sales consultants in Las Vegas, NV. The organization had increased market share and achieved record sales over the past three years; however, in the shadow of this success lurked an obstacle that…

  10. Tunisia: high fertility stalls development.

    Science.gov (United States)

    Barberis, M

    1985-01-01

    Despite government policy enacted in 1964 to reduce fertility in order to hasten socioeconomic progress, population pressures continue to impair development in Tunisia. The birth rate fell 20% over the last 2 decades, but this accomplishment has been outweighed by a 50% decline in mortality rates. As a result, the rate of natural population increase has remained relatively constant at 2.5%/year. The initial decline in fertility that followed introduction of the national family planning program appears to have reached a plateau, explained in part by the resurgence of conservatism and religious fundamentalism and the consequent emphasis on women's childbearing roles. Unemployment in rural areas has led to widespread migration and unemployment is as high as 20% in the nonagricultural sector. Many young Tunisians lack adequate educational preparation to enter the labor force; in 1982, 27% of new job entrants could not read or write. The government's plan to decentralize development to stabilize population and achieve equilibrium between regions has been thwarted by the pace of population growth and limited resources. The rural regions where population is increasing the fastest are also the most difficult to reach with family planning programs. On the other hand, there have been some successes in this area when services have been adapted to the lifestyle and traditions of those in these isolated rural villages.

  11. Robots are stalling in Fukushima

    International Nuclear Information System (INIS)

    Anon.

    2012-01-01

    Whereas robots were expected to be the heroes of the cleaning up of radioactive zones of the Fukushima power station, they fall, lack of autonomy, or stay prisoners of debris. After having briefly described how these robots look like (the characteristics of four models are given, two Japanese and two American robots), this article outlines that they resist quite well to radioactivity, but are rather slow and are not used all at the same time: some are being maintained, some are trapped in debris. Thus, they perform a mission once a week, with finally less than hundred hours of operation for each of them. They are often trapped by debris, their movements are often difficult (notably in front of stairs or of debris), their battery lacks autonomy, and they did not significantly reduce the exposure of humans to radioactivity, but they open perspectives for new devices

  12. Natural seed fall in white pine (Pinus strobes L.) stands of varying density

    Science.gov (United States)

    Raymond E. Graber

    1970-01-01

    Seed fall was observed in three stands of mature white pines at stand basal-area densities of 80, 120, and 187 square feet per acre. It was found that the intermediate-density stand produced nearly 50 percent more seed than the stands of other densities. During a good seed year this stand produced 59 pounds of dry sound seed per acre. Most of the seeds were dispersed...

  13. A New Standing Posture Detector to Enable People with Multiple Disabilities to Control Environmental Stimulation by Changing Their Standing Posture through a Commercial Wii Balance Board

    Science.gov (United States)

    Shih, Ching-Hsiang; Shih, Ching-Tien; Chiang, Ming-Shan

    2010-01-01

    This study assessed whether two persons with multiple disabilities would be able to control environmental stimulation using body swing (changing standing posture) and a Wii Balance Board with a newly developed standing posture detection program (i.e. a new software program turns a Wii Balance Board into a precise standing posture detector). The…

  14. Situating the Embodied Mind in a Landscape of Standing Affordances for Living Without Chairs: Materializing a Philosophical Worldview.

    Science.gov (United States)

    Rietveld, Erik

    2016-07-01

    Sitting too much is unhealthy, but a widespread habit in many societies. Realizing behavioral change in this area is hard. Our societies promote being seated via the way its places are structured: they are filled with chairs for example. How can we make healthier environments that invite people to move around more? This article shows how philosophical research in the area of embodied/enactive cognitive science let to a built vision for the office of the future, of 2025. Multidisciplinary studio RAAAF [Rietveld Architecture-Art-Affordances] and visual artist Barbara Visser built this world without chairs, titled The End of Sitting. This large rock-like landscape integrates many affordances for standing. Affordances are the possibilities for action provided by the environment. This landscape of standing affordances allows people to work standing while being supported by the material structure of the environment. This unorthodox working landscape is both an enactive art installation and the materialization of a philosophical worldview that understands people as embodied minds situated in a landscape of affordances. It stimulates reflection on the way built environments can naturally invite more active and healthy behavior.

  15. Posture as index for approach-avoidance behavior

    NARCIS (Netherlands)

    Eerland, A.|info:eu-repo/dai/nl/412493543; Guadalupe, Tulio; Franken, Ingmar; Zwaan, Rolf

    2012-01-01

    Approach and avoidance are two behavioral responses that make people tend to approach positive and avoid negative situations. This study examines whether postural behavior is influenced by the affective state of pictures. While standing on the Wii™ Balance Board, participants viewed pleasant,

  16. Posture as index for Approach-Avoidance behavior

    NARCIS (Netherlands)

    A. Eerland (Anita); T. Guadalupe (Tulio); I.H.A. Franken (Ingmar); R.A. Zwaan (Rolf)

    2012-01-01

    textabstractApproach and avoidance are two behavioral responses that make people tend to approach positive and avoid negative situations. This study examines whether postural behavior is influenced by the affective state of pictures. While standing on the Wii™ Balance Board, participants viewed

  17. Automatic recognition of lactating sow behaviors through depth image processing

    Science.gov (United States)

    Manual observation and classification of animal behaviors is laborious, time-consuming, and of limited ability to process large amount of data. A computer vision-based system was developed that automatically recognizes sow behaviors (lying, sitting, standing, kneeling, feeding, drinking, and shiftin...

  18. Functional pelvic orientation measured from lateral standing and sitting radiographs.

    Science.gov (United States)

    DiGioia, Anthony M; Hafez, Mahmoud A; Jaramaz, Branislav; Levison, Timothy J; Moody, James E

    2006-12-01

    We prospectively obtained preoperative and 3-month postoperative lateral pelvic radiographs in the standing and sitting positions from 84 patients who underwent total hip arthroplasty. We measured pelvic orientation (flexion extension) using the anterior pelvic plane as defined by the anterior superior iliac spines and pubic tubercles as references. There was a trend towards upright pelvic alignment when standing, with a mean anterior pelvic plane angle of 1.2 degrees (range, -22 degrees - +27 degrees). In the sitting position the pelvis tended to extend posteriorly, with a mean anterior pelvic plane angle of -36.2 degrees (range, -64 degrees - +4 degrees). There was a wide variation in the arc of pelvic flexion extension as patients moved from standing to sitting, with are of pelvic motion in some patients as mobile as 70 degrees and in others as stiff as 5 degrees. There was no significant variation between males and females or between preoperative and postoperative pelvic flexion extension. There were substantial variations in pelvic orientation when comparing standing and sitting for an individual patient and between different patients. This variation can be unpredictable, and may influence implant alignment and stability after total hip arthroplasty.

  19. Design of a quadrotor flight test stand for system identification

    CSIR Research Space (South Africa)

    Beharie, MM

    2015-01-01

    Full Text Available This paper presents the design, development and construction of a flight test stand for a quadrotor UAV. As opposed to alternate forms of UAV, the power plant in the case of the quadrotor serves a dual purpose of control and propulsion. Since...

  20. 21 CFR 14.100 - List of standing advisory committees.

    Science.gov (United States)

    2010-04-01

    ... emerging food safety, food science, and nutrition issues that FDA considers of primary importance in the... 21 Food and Drugs 1 2010-04-01 2010-04-01 false List of standing advisory committees. 14.100 Section 14.100 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES...

  1. Generalized height-diameter models for Populus tremula L. stands

    African Journals Online (AJOL)

    USER

    2010-07-12

    Jul 12, 2010 ... Using permanent sample plot data, selected tree height and diameter functions were evaluated for their predictive abilities for Populus tremula stands in Turkey. Two sets of models were evaluated. The first set included five models for estimating height as a function of individual tree diameter; the second set.

  2. Shock stand off Calculations for Hemisphere in Hypersonic Flows

    International Nuclear Information System (INIS)

    Hanif, M.; Ghaffar, A.; Bilal, S.; Zahir, S.; Khan, M.A.

    2004-01-01

    The shape and location of shock has been studied by solving the axi symmetric Navier Stokes Equations for a hemisphere in hypersonic flow. The effect of Mach number on shock stand-off distance has been investigated. It is found that the shock location varies with Mach number and the free stream conditions at a given nose radius. (author)

  3. Assessing the Economic and Environmental Prospects of Stand-By ...

    African Journals Online (AJOL)

    This paper presents an economic analysis of two stand-by power supply options for a typical Nigerian household namely diesel generator plant and solar powered systems. The analysis reveals that solar systems are the most economically viable. The environmental benefits associated with substituting diesel powered ...

  4. The Relationship Between Foot and Pelvic Alignment While Standing

    Directory of Open Access Journals (Sweden)

    Khamis Sam

    2015-06-01

    Full Text Available A normal motion and segmental interrelationship has been determined as a significant factor in normal function. Yet, the relationship between distal segments and pelvic alignment needs further investigation. The aim of this study was to investigate the interrelationship between distal and proximal lower extremity segments while standing and during induced feet hyperpronation. Changes in alignment of the pelvis and lower extremities were measured at a gait laboratory using the VICON 612 computerized motion analysis system. Thirty-five healthy volunteer subjects were recruited. Four randomized repeated-measure standing modes were used: standing directly on the floor and then on three wedges angled at 10°, 15° and 20° to induce bilateral hyperpronation for 20 seconds. A significant (p<0.05 bi-variate relationship was found between the anterior pelvic tilt and thigh internal rotation, in all four standing positions (.41≤r≤.46, in all p<0.014. A combined effect of rotational alignment between segments and the cumulative effect of foot hyperpronation on pelvic tilt revealed that only the shank significantly affected pelvic alignment, acting as a mediator between a foot and a thigh with the thigh having a crude significant effect on the pelvis. When internal rotation of the shank occurs, calcaneal eversion couples with thigh internal rotation and anterior pelvic tilt. It can be concluded that in response to induced hyperpronation, the shank is a pivotal segment in postural adjustment.

  5. Relative size and stand age determine Pinus banksiana mortality

    Science.gov (United States)

    Han Y. H. Chen; Songling Fu; Robert A. Monserud; Ian C. Gillies

    2008-01-01

    Tree mortality is a poorly understood process in the boreal forest. Whereas large disturbances reset succession by killing all or most trees, background tree mortality was hypothesized to be affected by competition, ageing, and stand composition. We tested these hypotheses on jack pine (Pinus banksiana Lamb.) mortality using data from long-term...

  6. Infrared differential absorption lidar for stand-off detection of ...

    Indian Academy of Sciences (India)

    2014-02-14

    Feb 14, 2014 ... Abstract. A compact trolley-mounted pulsed transverse electric atmospheric pressure (TEA) car- bon dioxide laser-based differential absorption lidar (DIAL) system capable of stand-off detection of chemical clouds in aerosol and vapour form upto about 200 m range in the atmosphere has been developed ...

  7. SOUTH AFRICA AND THE SADC STAND-BY FORCE

    African Journals Online (AJOL)

    hennie

    prevailing at the time of their establishment, which, however, can change over time. (Cox 1981:136). ... pursuit of peace, democracy and stability for economic growth and development in the region and within South ... the organisation would be able to form a regional stand-by brigade for the use of the. African Union (AU) as ...

  8. Standing surface acoustic wave (SSAW) based multichannel cell sorting.

    Science.gov (United States)

    Ding, Xiaoyun; Lin, Sz-Chin Steven; Lapsley, Michael Ian; Li, Sixing; Guo, Xiang; Chan, Chung Yu; Chiang, I-Kao; Wang, Lin; McCoy, J Philip; Huang, Tony Jun

    2012-11-07

    We introduce a novel microfluidic device for cell sorting in continuous flow using tunable standing surface acoustic waves. This method allows individual cells to be precisely directed into five different outlet channels in a single step. It is versatile, simple, label-free, non-invasive, and highly controllable.

  9. Step Prediction During Perturbed Standing Using Center Of Pressure Measurements

    Directory of Open Access Journals (Sweden)

    Milos R. Popovic

    2007-04-01

    Full Text Available The development of a sensor that can measure balance during quiet standing and predict stepping response in the event of perturbation has many clinically relevant applica- tions, including closed-loop control of a neuroprothesis for standing. This study investigated the feasibility of an algorithm that can predict in real-time when an able-bodied individual who is quietly standing will have to make a step to compensate for an external perturbation. Anterior and posterior perturbations were performed on 16 able-bodied subjects using a pul- ley system with a dropped weight. A linear relationship was found between the peak center of pressure (COP velocity and the peak COP displacement caused by the perturbation. This result suggests that one can predict when a person will have to make a step based on COP velocity measurements alone. Another important feature of this finding is that the peak COP velocity occurs considerably before the peak COP displacement. As a result, one can predict if a subject will have to make a step in response to a perturbation sufficiently ahead of the time when the subject is actually forced to make the step. The proposed instability detection algorithm will be implemented in a sensor system using insole sheets in shoes with minitur- ized pressure sensors by which the COPv can be continuously measured. The sensor system will be integrated in a closed-loop feedback system with a neuroprosthesis for standing in the near future.

  10. Impaired standing balance : unraveling the underlying cause in elderly

    NARCIS (Netherlands)

    Pasma, Jantsje Henrieke

    2015-01-01

    Impaired balance is often seen in elderly and can result in impaired mobility and finally in falling. Failure of compensation strategies or deterioration of underlying systems involved in standing balance could result in impaired balance. To apply targeted interventions to improve balance, it is

  11. A stricter condition for standing balance after unexpected perturbations

    NARCIS (Netherlands)

    Hof, At L; Curtze, Carolin

    2016-01-01

    In order to account for the dynamic nature of balance, the concept of the 'extrapolated centre of mass' XcoM has been introduced (Hof et al., 2005). The law for standing balance was then formulated as: the XcoM should remain within the Base of Support (BoS). This law, however, does not take into

  12. Quantitative Analysis of Complex Tropical Forest Stands: A Review ...

    African Journals Online (AJOL)

    FIRST LADY

    Disciplinary Journal, Ethiopia. Vol. 4 (3a) July, 2010. ISSN 1994-9057 (Print). ISSN 2070-0083 (Online). Quantitative Analysis of Complex Tropical Forest. Stands: A Review (Pp. 367-377). Oyebade, B. A. - Forest Biometrics & Measurement Unit, ...

  13. The energy cost for balance control during upright standing

    NARCIS (Netherlands)

    Houdijk, J.H.P.; Fickert, R.; van Velzen, J.; van Bennekom, C.A.M.

    2009-01-01

    The aim of this study was to investigate whether balance control during a static upright standing task with and without balance perturbations elicits a significant and meaningful metabolic energy demand and to test whether this energy demand correlates with conventional posturography measures for

  14. Three scales of aerial photography compared for making stand measurements

    Science.gov (United States)

    Earl J. Rogers; Gene Avery; Roy A. Chapman

    1959-01-01

    Three scales of aerial photography were tested in an attempt to determine the best scale to use in forest surveying. This was done by comparing photo measurements of average tree height, average crown diameter, and crown-closure percent. These stand variables were selected for testing because of their applicability in making aerial estimates of timber volume.

  15. Excitation of Standing Waves by an Electric Toothbrush

    Science.gov (United States)

    Cros, Ana; Ferrer-Roca, Chantal

    2006-01-01

    There are a number of ways of exciting standing waves in ropes and springs using non-commercial vibrators such as loudspeakers, jigsaws, motors, or a simple tuning fork, including the rhythmical shaking of a handheld Slinky. We have come up with a very simple and cheap way of exciting stationary waves in a string, which anyone, particularly…

  16. 46 CFR Sec. 2 - Stand-by agreements.

    Science.gov (United States)

    2010-10-01

    ... ADMINISTRATION, DEPARTMENT OF TRANSPORTATION B-CONTROL AND UTILIZATION OF PORTS OPERATING CONTRACT Sec. 2 Stand-by agreements. The Director NSA, Maritime Administration, in advance of an emergency, may negotiate... 1901) under the control of the Maritime Administration and allocated for long term exclusive use by the...

  17. Quantitative Analysis of Complex Tropical Forest Stands: A Review ...

    African Journals Online (AJOL)

    The importance of data analysis in quantitative assessment of natural resources remains significant in the sustainable management of complex tropical forest resources. Analyses of data from complex tropical forest stands have not been easy or clear due to improper data management. It is pivotal to practical researches ...

  18. Measuring light in uneven-aged hardwood stands

    Science.gov (United States)

    Leon S. Minckler

    1961-01-01

    Light, essential in the development of a forest, can be controlled within a stand by silvicultural practices. Measuring it, however, has always been a problem for silvicultural researchers. And accurate measurements are necessary, especially in studying the relation between light and reproduction. The desired objective is to measure the total visible light in specific...

  19. Evaluation of three classifiers in mapping forest stand types using ...

    African Journals Online (AJOL)

    EJIRO

    applied for classification of the image. Supervised classification technique using maximum likelihood algorithm is the most commonly and widely used method for land cover classification (Jia and Richards, 2006). In Australia, the maximum likelihood classifier was effectively used to map different forest stand types with high.

  20. Sit-to-stand at different periods of pregnancy.

    Science.gov (United States)

    Lou, S Z; Chou, Y L; Chou, P H; Lin, C J; Chen, U C; Su, F C

    2001-03-01

    This study was performed to determine the biomechanics of chair rising by pregnant women. Relative body joint position and ground reaction forces were measured by a motion analysis system and one force plate. Physiological and psychological changes during pregnancy impose postural demands and limit the performance of daily living activities such as rising from sitting to standing position. Twenty-four pregnant women, divided into three groups, were studied performing sit-to-stand transition from an armless and adjustable chair. By kinematic and kinetic analysis, the angles and moments of hip, knee and ankle joints were investigated. The chair height has great influence on knee joint and hip joint moments, but less on ankle joints. In the third trimester for all chair heights, because of a marked increase in abdominal depth, the maximum hip moment is significantly less than that in first trimester, while the maximum knee moment is significantly larger. Pregnant women in third trimester produced larger knee moment during sit-to-stand transition from lower chair height. The mechanism of sit-to-stand is affected by the physical changes of pregnant women at different periods of pregnancy, e.g. increased loading of knee joint and decreased hip joint moment, especially in the last trimester period of pregnancy.