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Sample records for high-intensity impact loads

  1. High-intensity tasks with external load in military applications: a review.

    PubMed

    O'Neal, Eric K; Hornsby, Jared H; Kelleran, Kyle J

    2014-09-01

    This article provides a synopsis of the limited investigations examining the impact of external load (EL) on performance of high-intensity tasks under load (HITL), EL training intervention effects on HITL performance, and injuries from EL training. Repetitive lifting tasks and initiation of locomotion, such as rapidly moving from a prone position to sprinting appear to be more hindered by EL than maximal sprinting velocity and may explain why training with EL does not improve obstacle course or prolonged (200-300 yard shuttle) drills. EL training appears to offer very little if any benefit for HITL in lesser trained populations. This contrast results of multiple studies incorporating ≥ 3 weeks of prolonged hypergravity interventions (wearing EL during daily activities) in elite anaerobic athletes, indicating EL training stimulus is likely only beneficial to well-trained soldiers. Women and lesser trained individuals appear to be more susceptible to increased injury with EL training. A significant limitation concerning current HITL knowledge is the lack of studies incorporating trained soldiers. Future investigations concerning the effects of HITL on marksmanship, repetitive lifting biomechanics, efficacy of hypergravity training for military personnel, and kinematics of sprinting from tactical positions with various EL displacements and technique training are warranted.

  2. Relationship Between Accelerometer Load, Collisions, and Repeated High-Intensity Effort Activity in Rugby League Players.

    PubMed

    Gabbett, Tim J

    2015-12-01

    Triaxial accelerometers have been critical in providing information on the high-acceleration, low-velocity movements that occur in team sports. In addition, these sensors have proven to be useful in quantifying the activities that do not involve the vertical acceleration associated with locomotion (e.g., tackling, on-ground wrestling, and grappling). This study investigated the relationship between Player Load (PL), 2D Player Load (2DPL), and Player Load Slow (PL Slow), collisions, and repeated high-intensity effort (RHIE) activity in rugby league players. One hundred and eighty-two rugby league players (age, 24.3 ± 3.3 years) participated in this study. Movement was recorded using a global positioning system unit sampling at 10 Hz and triaxial accelerometer sampling at 100 Hz. Analysis was completed during 26 matches (totaling 386 appearances). Pearson product-moment correlation coefficients were used to determine relationships between PL, 2DPL, and PL Slow and total collisions and RHIE activity. When all players were considered, weak relationships were found between PL and the number of collisions and RHIE bouts performed. However, PL was strongly associated (p ≤ 0.05) with total distance, low-speed activity, high-speed running distance, total collisions, and the number of RHIE bouts for forwards and hookers. Weak and typically insignificant relationships were found between PL, 2DPL, and PL Slow and the number of collisions and RHIE bouts performed by the adjustables and outside backs positional groups. The relationships between PL and the number of collisions and RHIE bouts are stronger in positions where contact and repeated-effort demands are high. From a practical perspective, these results suggest that PL, 2DPL, and PL Slow offer useful "real-time" measures of collision and RHIE activity, particularly in forwards and hookers, to inform interchange strategies and ensure players are training at an adequate intensity.

  3. The effect of high intensity ultrasound on the loading of Au nanoparticles into titanium dioxide.

    PubMed

    Belova, Valentina; Borodina, Tatiana; Möhwald, Helmuth; Shchukin, Dmitry G

    2011-01-01

    Novel metal/semiconductor nanocomposites have been synthesized from pre-formed components by applying high intensity ultrasound irradiation. Positively and negatively charged Au nanoparticles were intercalated into mesoporous TiO(2) by sonication. The synthesized nanocomposites with implanted gold nanoparticles possess a narrow pore-size distribution around 7 nm and a large surface area of about 210 m(2)/g. The intercalation of the Au nanoparticles into the TiO(2) framework depends on the charge of the Au nanoparticles, time and amplitude of ultrasonic treatment. The experiments show that at 20 min of ultrasonic irradiation the volume fraction of the negatively charged Au nanoparticles intercalated into TiO(2) is 15%. By contrast, at the same time, 8.1% of positively charged Au nanoparticles with a diameter of about 6-7 nm enters into the TiO(2) matrix. The characterization of the samples was carried out by X-ray diffraction, transmission electron microscopy, high-resolution transmission electron microscopy, scanning electron microscopy, Fourier transform infrared measurements and BET analysis. The structure of TiO(2) was not considerably affected by the intercalation of the Au nanoparticles. TiO(2) doped with negatively charged Au nanoparticles presented a higher photocatalytic activity (75 wt.%) than TiO(2) loaded with positively charged Au nanoparticles (62 wt.%), because of an enlarged surface area and quantity of Au nanoparticles in titania. Copyright © 2010 Elsevier B.V. All rights reserved.

  4. The role of strength and power during performance of high intensity military tasks under heavy load carriage.

    PubMed

    Mala, Jesse; Szivak, Tunde K; Flanagan, Shawn D; Comstock, Brett A; Laferrier, Justin Z; Maresh, Carl M; Kraemer, William J

    2015-01-01

    Previous research has investigated the physiological determinants of heavy load carriage while performing medium to long distance road marching, yet research examining the physiological underpinnings of high-intensity battlefield tasks is limited. This study sought to examine the role of strength and power during high-intensity combat tasks under heavy load carriage. Eighteen recreationally trained men (mean±SD: age, 21±2 years; height, 172±6 cm; weight, 80±13 kg) participated in this study and performed an anaerobic combat course under 2 randomized experimental conditions; unloaded and loaded. Subjects performed 3 trials under each condition on separate days, with a 5-minute rest between each trial. In the unloaded trial, subjects wore a uniform with boots weighing approximately 3.2 kg. During the loaded trial, in addition to the uniform and boots, subjects wore Interceptor body armor (6.94 kg-9.10 kg) and a MOLLE rucksack weighing 30 kg. The course consisted of 3 consecutive tasks, which began from the prone position, led into a 30 m sprint, followed by a 27 m zigzag run, and ended with a 10 m casualty drag weighing approximately 79.4 kg. Pearson correlations showed significant (P≤.05) strong correlations between lower body strength (r=-0.63, -0.62), lower body power (r=-0.67, -0.67) and upper body strength (r=-0.60, -0.62) and overall performance times in the unloaded and loaded condition, respectively. Strength and power are strongly related to high-intensity military tasks with and without heavy load carriage.

  5. Can Trained Runners Effectively Attenuate Impact Acceleration During Repeated High-Intensity Running Bouts?

    PubMed

    Clansey, Adam C; Lake, Mark J; Wallace, Eric S; Feehally, Tom; Hanlon, Michael

    2016-06-01

    The purpose of this study was to investigate the effects of prolonged high-intensity running on impact accelerations in trained runners. Thirteen male distance runners completed two 20-minute treadmill runs at speeds corresponding to 95% of onset of blood lactate accumulation. Leg and head accelerations were collected for 20 s every fourth minute. Rating of perceived exertion (RPE) scores were recorded during the third and last minute of each run. RPE responses increased (P < .001) from the start (11.8 ± 0.9, moderate intensity) of the first run to the end (17.7 ± 1.5, very hard) of the second run. Runners maintained their leg impact acceleration, impact attenuation, stride length, and stride frequency characteristics with prolonged run duration. However, a small (0.11-0.14g) but significant increase (P < .001) in head impact accelerations were observed at the end of both first and second runs. It was concluded that trained runners are able to control leg impact accelerations during sustained high-intensity running. Alongside the substantial increases in perceived exertion levels, running mechanics and frequency domain impact attenuation levels remained constant. This suggests that the present trained runners are able to cope from a mechanical perspective despite an increased physiological demand.

  6. Carbohydrate ingestion during prolonged high-intensity intermittent exercise: impact on affect and perceived exertion.

    PubMed

    Backhouse, S H; Ali, A; Biddle, S J H; Williams, C

    2007-10-01

    This study was designed to determine the effects of ingesting a carbohydrate (CHO) solution on affective states and rating of perceived exertion (RPE) during prolonged intermittent high-intensity exercise. Seventeen male soccer players completed a prolonged intermittent high-intensity exercise protocol for 90 min on two occasions, separated by at least 7 days. Participants consumed either a 6.4% CHO (0.6 g/kg body mass (BM)/h) or an artificially sweetened placebo (PLA) solution immediately before (8 mL/kg BM) and every 15 min (3 mL/kg BM) during exercise in a double-blind, counterbalanced design. Pleasure-displeasure, perceived activation, RPE and plasma glucose concentration was assessed. The results showed that compared with the CHO trial, perceived activation were lower in the placebo trial during the last 30 min of exercise and this was accompanied by lowered plasma glucose concentrations. In the CHO trial, RPE was maintained in the last 30 min of exercise but carried on increasing in the PLA trial. Therefore, CHO ingestion during prolonged high-intensity exercise appears to elicit an enhanced perceived activation profile that may impact upon task persistence and performance. This finding is in addition to the physiological and metabolic benefits of the exogenous energy supply.

  7. High intensity single bunch operation with heavy periodic transient beam loading in wide band rf cavities

    NASA Astrophysics Data System (ADS)

    Tamura, Fumihiko; Hotchi, Hideaki; Schnase, Alexander; Yoshii, Masahito; Yamamoto, Masanobu; Ohmori, Chihiro; Nomura, Masahiro; Toda, Makoto; Shimada, Taihei; Hasegawa, Katsushi; Hara, Keigo

    2015-09-01

    The rapid cycling synchrotron (RCS) in the Japan Proton Accelerator Research Complex (J-PARC) was originally designed to accelerate two high intensity bunches, while some of neutron experiments in the materials and life science experimental facility and a muon experiment using main ring beams require a single bunch operation mode, in which one of the two rf buckets is filled and the other is empty. The beam intensity in the single bunch operation has been limited by longitudinal beam losses due to the rf bucket distortions by the wake voltage of the odd harmonics (h =1 ,3 ,5 ) in the wide band magnetic alloy cavities. We installed an additional rf feedforward system to compensate the wake voltages of the odd harmonics (h =1 ,3 ,5 ). The additional system has a similar structure as the existing feedforward system for the even harmonics (h =2 ,4 ,6 ). We describe the function of the feedforward system for the odd harmonics, the commissioning methodology, and the commissioning results. The longitudinal beam losses during the single bunch acceleration disappeared with feedforward for the odd harmonics. We also confirmed that the beam quality in the single bunch acceleration are similar to that of the normal operation with two bunches. Thus, high intensity single bunch acceleration at the intensity of 2.3 ×1013 protons per bunch has been achieved in the J-PARC RCS. This article is a follow-up of our previous article, Phys. Rev. ST Accel. Beams 14, 051004 (2011). The feedforward system extension for single bunch operation was successful.

  8. Revisiting the effect of posture on high-intensity constant-load cycling performance in men and women.

    PubMed

    Egaña, Mikel; Smith, Stephanie; Green, Simon

    2007-03-01

    It was recently observed that inclining the body from a supine to upright position improved the performance of high-intensity, constant-load cycling to a larger extent in men than women (Egaña et al. in Eur J Appl Physiol 96:1-9, 2006), although this gender-related effect was based on a small number of men (n = 5) and women (n = 5). To explore this effect further, we studied the effect of body tilt on cycling performance in a larger and different group of men (n = 8) and women (n = 18). Peak power, peak VO2 and the ventilatory threshold (VT) were determined during an upright maximal graded cycle test, and a high-intensity test (80% peak power) was performed to failure in both the upright and supine positions. Performance was significantly longer in the upright compared with supine position in men (17.4 +/- 7.7 vs. 7.6 +/- 3.4 min) and women (14.1 +/- 6.0 vs. 6.0 +/- 3.7 min). The magnitude of this postural effect was not significantly different between men and women; whereas it was significantly correlated with the relative intensity of exercise expressed as a function of VT (r = -0.39). These data demonstrate that the postural effect on high-intensity cycling performance is not influenced by gender; but that it is related to the intensity of exercise relative to the ventilatory threshold.

  9. Feasibility and Impact of High-Intensity Walking Training in Frail Older Adults.

    PubMed

    Danilovich, Margaret K; Conroy, David E; Hornby, T George

    2017-09-23

    To investigate the impact of high-intensity walking training (HIWT) on prefrail and frail older adults, five assisted living residents underwent a supervised 12-session intervention. The intervention consisted of 30 min of HIWT at 70-80% of heart rate reserve or ratings of 15 to 17 (hard to very hard) on the Borg Rating of Perceived Exertion scale. Training included walking at fast speeds, multi-directions, stairs, and outdoor surfaces with and without an assistive device. Training significantly reduced frailty using the SHARE-FI (p = .008), increased fast gait speed (p = .01), improved 6-min walk test distance (p = .03), and enhanced Berg Balance Scale scores (p = .03). There were no adverse events and all participants reached target training intensity in all 12 sessions. Participants viewed the walking intervention as highly satisfactory (9.6/10 on a Likert scale) and 100% recommended that the assisted living facility should offer HIWT as part of routine programming.

  10. Impact of high-intensity ultrasound on the formation of lactulose and Maillard reaction glycoconjugates.

    PubMed

    Corzo-Martínez, Marta; Montilla, Antonia; Megías-Pérez, Roberto; Olano, Agustín; Moreno, F Javier; Villamiel, Mar

    2014-08-15

    The impact of high-intensity ultrasound (US) on the formation of lactulose during lactose isomerization and on the obtention of lysine-glucose glycoconjugates during Maillard reaction (MR) has been studied, respectively, in basic and neutral media. As compared to equivalent conventional heat treatments, a higher formation of furosine, as indicator of initial steps of MR, was observed together with more advance of the reaction in US treated samples, this effect being more pronounced with the increase of US amplitude (50-70%) and temperature (25-40 °C). Regarding the influence of US on lactulose formation, in general, in a buffered system (pH 10.0), US at 70% of amplitude and 60 °C increased the rate of lactose isomerization, higher values of lactulose, epilactose and galactose being observed in comparison to conventional heating. The results of this work showed an acceleration of both reactions by US, indicating its usefulness to promote the formation of functional ingredients. Copyright © 2014 Elsevier Ltd. All rights reserved.

  11. High-intensity interval training, solutions to the programming puzzle. Part II: anaerobic energy, neuromuscular load and practical applications.

    PubMed

    Buchheit, Martin; Laursen, Paul B

    2013-10-01

    High-intensity interval training (HIT) is a well-known, time-efficient training method for improving cardiorespiratory and metabolic function and, in turn, physical performance in athletes. HIT involves repeated short (<45 s) to long (2-4 min) bouts of rather high-intensity exercise interspersed with recovery periods (refer to the previously published first part of this review). While athletes have used 'classical' HIT formats for nearly a century (e.g. repetitions of 30 s of exercise interspersed with 30 s of rest, or 2-4-min interval repetitions ran at high but still submaximal intensities), there is today a surge of research interest focused on examining the effects of short sprints and all-out efforts, both in the field and in the laboratory. Prescription of HIT consists of the manipulation of at least nine variables (e.g. work interval intensity and duration, relief interval intensity and duration, exercise modality, number of repetitions, number of series, between-series recovery duration and intensity); any of which has a likely effect on the acute physiological response. Manipulating HIT appropriately is important, not only with respect to the expected middle- to long-term physiological and performance adaptations, but also to maximize daily and/or weekly training periodization. Cardiopulmonary responses are typically the first variables to consider when programming HIT (refer to Part I). However, anaerobic glycolytic energy contribution and neuromuscular load should also be considered to maximize the training outcome. Contrasting HIT formats that elicit similar (and maximal) cardiorespiratory responses have been associated with distinctly different anaerobic energy contributions. The high locomotor speed/power requirements of HIT (i.e. ≥95 % of the minimal velocity/power that elicits maximal oxygen uptake [v/p(·)VO(2max)] to 100 % of maximal sprinting speed or power) and the accumulation of high-training volumes at high-exercise intensity (runners can

  12. The Impact of Moderate and High Intensity Total Body Fatigue on Passing Accuracy in Expert and Novice Basketball Players

    PubMed Central

    Lyons, Mark; Al-Nakeeb, Yahya; Nevill, Alan

    2006-01-01

    Despite the acknowledged importance of fatigue on performance in sport, ecologically sound studies investigating fatigue and its effects on sport-specific skills are surprisingly rare. The aim of this study was to investigate the effect of moderate and high intensity total body fatigue on passing accuracy in expert and novice basketball players. Ten novice basketball players (age: 23.30 ± 1.05 yrs) and ten expert basketball players (age: 22.50 ± 0.41 yrs) volunteered to participate in the study. Both groups performed the modified AAHPERD Basketball Passing Test under three different testing conditions: rest, moderate intensity and high intensity total body fatigue. Fatigue intensity was established using a percentage of the maximal number of squat thrusts performed by the participant in one minute. ANOVA with repeated measures revealed a significant (F 2,36 = 5.252, p = 0.01) level of fatigue by level of skill interaction. On examination of the mean scores it is clear that following high intensity total body fatigue there is a significant detriment in the passing performance of both novice and expert basketball players when compared to their resting scores. Fundamentally however, the detrimental impact of fatigue on passing performance is not as steep in the expert players compared to the novice players. The results suggest that expert or skilled players are better able to cope with both moderate and high intensity fatigue conditions and maintain a higher level of performance when compared to novice players. The findings of this research therefore, suggest the need for trainers and conditioning coaches in basketball to include moderate, but particularly high intensity exercise into their skills sessions. This specific training may enable players at all levels of the game to better cope with the demands of the game on court and maintain a higher standard of play. Key Points Aim: to investigate the effect of moderate and high intensity total body fatigue on

  13. Benchmark of the IMPACT Code for High Intensity Beam DynamicsSimulation

    SciTech Connect

    Qiang, J.; Ryne, R.D.

    2006-11-16

    The IMPACT (Integrated Map and Particle Accelerator Tracking) code was first developed under Computational Grand Challenge project in the mid 1990s [1]. It started as a three-dimensional (3D) data parallel particle-in-cell (PIC) code written in High Performance Fortran. The code used a split-operator based method to solve the Hamiltonian equations of motion. It contained linear transfer maps for drifts, quadrupole magnets and rf cavities. The space-charge forces were calculated using an FFT-based method with 3D open boundary conditions and longitudinal periodic boundary conditions. This code was completely rewritten in the late 1990s based on a message passing parallel programming paradigm using Fortran 90 and MPI following an object-oriented software design. This improved the code's scalability on large parallel computer systems and also gave the code better software maintainability and extensibility [2]. In the following years, under the SciDAC-1 accelerator project, the code was extended to include more accelerating and focusing elements such as DTL, CCL, superconducting linac, solenoid, dipole, multipoles, and others. Besides the original split-operator based integrator, a direct integration of Lorentz equations of motion using a leap-frog algorithm was also added to the IMPACT code to handle arbitrary external nonlinear fields. This integrator can read in 3D electromagnetic fields in a Cartesian grid or in a cylindrical coordinate system. Using the Lorentz integrator, we also extended the original code to handle multiple charge-state beams. The space-charge solvers were also extended to include conducting wall effects for round and rectangular pipes with longitudinal open and periodic boundary conditions. Recently, it has also been extended to handle short-range wake fields (longitudinal monopole and transverse dipole) and longitudinal coherent synchrotron radiation wake fields. Besides the parallel macroparticle tracking code, an rf linac lattice design code

  14. Experimental investigation on dynamic response of aircraft panels excited by high-intensity acoustic loads in thermal environment

    NASA Astrophysics Data System (ADS)

    WU, Z. Q.; LI, H. B.; ZHANG, W.; CHENG, H.; KONG, F. J.; LIU, B. R.

    2016-09-01

    Metallic and composite panels are the major components for thermal protection system of aircraft vehicles, which are exposed to a severe combination of aerodynamic, thermal and acoustic environments during hypersonic flights. A thermal-acoustic testing apparatus which simulates thermal and acoustic loads was used to validate the integrity and the reliability of these panels. Metallic and ceramic matrix composite flat panels were designed. Dynamic response tests of these panels were carried out using the thermal acoustic apparatus. The temperature of the metallic specimen was up to 400 °C, and the temperature of the composite specimen was up to 600 °C. Moreover, the acoustic load was over 160 dB. Acceleration responses of these testing panels were measured using high temperature instruments during the testing process. Results show that the acceleration root mean square values are dominated by sound pressure level of acoustic loads. Compared with testing data in room environment, the peaks of the acceleration dynamic response shifts obviously to the high frequency in thermal environment.

  15. Chronic and acute inspiratory muscle loading augment the effect of a 6-week interval program on tolerance of high-intensity intermittent bouts of running.

    PubMed

    Tong, Tom K; Fu, Frank H; Eston, Roger; Chung, Pak-Kwong; Quach, Binh; Lu, Kui

    2010-11-01

    This study examined the hypothesis that chronic (training) and acute (warm-up) loaded ventilatory activities applied to the inspiratory muscles (IM) in an integrated manner would augment the training volume of an interval running program. This in turn would result in additional improvement in the maximum performance of the Yo-Yo intermittent recovery test in comparison with interval training alone. Eighteen male nonprofessional athletes were allocated to either an inspiratory muscle loading (IML) group or control group. Both groups participated in a 6-week interval running program consisting of 3-4 workouts (1-3 sets of various repetitions of selected distance [100-2,400 m] per workout) per week. For the IML group, 4-week IM training (30 inspiratory efforts at 50% maximal static inspiratory pressure [P0] per set, 2 sets·d-1, 6 d·wk-1) was applied before the interval program. Specific IM warm-up (2 sets of 30 inspiratory efforts at 40% P0) was performed before each workout of the program. For the control group, neither IML was applied. In comparison with the control group, the interval training volume as indicated by the repeatability of running bouts at high intensity was approximately 27% greater in the IML group. Greater increase in the maximum performance of the Yo-Yo test (control: 16.9 ± 5.5%; IML: 30.7 ± 4.7% baseline value) was also observed after training. The enhanced exercise performance was partly attributable to the greater reductions in the sensation of breathlessness and whole-body metabolic stress during the Yo-Yo test. These findings show that the combination of chronic and acute IML into a high-intensity interval running program is a beneficial training strategy for enhancing the tolerance to high-intensity intermittent bouts of running.

  16. Impact of Pre-Plasma on Fast Electron Generation and Transport from Short Pulse High Intensity Lasers

    NASA Astrophysics Data System (ADS)

    Peebles, J.; McGuffey, C.; Krauland, C.; Jarrott, L. C.; Sorokovikova, A.; Qiao, B.; Krasheninnikov, S.; Beg, F. N.; Wei, M. S.; Park, J.; Link, A.; Chen, H.; McLean, H. S.; Wagner, C.; Minello, V.; McCary, E.; Meadows, A.; Spinks, M.; Gaul, E.; Dyer, G.; Hegelich, B. M.; Martinez, M.; Donovan, M.; Ditmire, T.

    2014-10-01

    We present the results and analysis from recent short pulse laser matter experiments using the Texas Petawatt Laser to study the impact of pre-plasma on fast electron generation and transport. The experimental setup consisted of 3 separate beam elements: a main, high intensity, short pulse beam for the interaction, a secondary pulse of equal intensity interacting with a separate thin foil target to generate protons for side-on proton imaging and a third, low intensity, wider beam to generate a varied scale length pre-plasma. The main target consisted of a multilayer planar Al foil with a buried Cu fluor layer. The electron beam was characterized with multiple diagnostics, including several bremsstrahlung spectrometers, magnetic electron spectrometers and Cu-K α imaging. The protons from the secondary target were used to image the fields on the front of the target in the region of laser plasma interaction. Features seen in the interaction region by these protons will be presented along with characteristics of the generated electron beam. This work performed under the auspices of the US DOE under Contracts DE-FOA-0000583 (FES, NNSA).

  17. Development of the experimental procedure to examine the response of carbon fiber-reinforced polymer composites subjected to a high-intensity pulsed electric field and low-velocity impact.

    PubMed

    Hart, Robert J; Zhupanska, Olesya I

    2016-01-01

    A new fully automated experimental setup has been developed to study the response of carbon fiber reinforced polymer (CFRP) composites subjected to a high-intensity pulsed electric field and low-velocity impact. The experimental setup allows for real-time measurements of the pulsed electric current, voltage, impact load, and displacements on the CFRP composite specimens. The setup includes a new custom-built current pulse generator that utilizes a bank of capacitor modules capable of producing a 20 ms current pulse with an amplitude of up to 2500 A. The setup enabled application of the pulsed current and impact load and successfully achieved coordination between the peak of the current pulse and the peak of the impact load. A series of electrical, impact, and coordinated electrical-impact characterization tests were performed on 32-ply IM7/977-3 unidirectional CFRP composites to assess their ability to withstand application of a pulsed electric current and determine the effects of the pulsed current on the impact response. Experimental results revealed that the electrical resistance of CFRP composites decreased with an increase in the electric current magnitude. It was also found that the electrified CFRP specimens withstood higher average impact loads compared to the non-electrified specimens.

  18. Development of the experimental procedure to examine the response of carbon fiber-reinforced polymer composites subjected to a high-intensity pulsed electric field and low-velocity impact

    NASA Astrophysics Data System (ADS)

    Hart, Robert J.; Zhupanska, Olesya I.

    2016-01-01

    A new fully automated experimental setup has been developed to study the response of carbon fiber reinforced polymer (CFRP) composites subjected to a high-intensity pulsed electric field and low-velocity impact. The experimental setup allows for real-time measurements of the pulsed electric current, voltage, impact load, and displacements on the CFRP composite specimens. The setup includes a new custom-built current pulse generator that utilizes a bank of capacitor modules capable of producing a 20 ms current pulse with an amplitude of up to 2500 A. The setup enabled application of the pulsed current and impact load and successfully achieved coordination between the peak of the current pulse and the peak of the impact load. A series of electrical, impact, and coordinated electrical-impact characterization tests were performed on 32-ply IM7/977-3 unidirectional CFRP composites to assess their ability to withstand application of a pulsed electric current and determine the effects of the pulsed current on the impact response. Experimental results revealed that the electrical resistance of CFRP composites decreased with an increase in the electric current magnitude. It was also found that the electrified CFRP specimens withstood higher average impact loads compared to the non-electrified specimens.

  19. High-intensity cannabis use associated with lower plasma HIV-1 RNA viral load among recently-infected people who use injection drugs

    PubMed Central

    Milloy, M-J; Marshall, Brandon; Kerr, Thomas; Richardson, Lindsey; Hogg, Robert; Guillemi, Silvia; Montaner, Julio SG; Wood, Evan

    2015-01-01

    Introduction and Aims Cannabis use is common among people who are living with HIV/AIDS. While there is growing pre-clinical evidence of the immunomodulatory and anti-viral effects of cannabinoids, their possible effects on HIV disease parameters in humans is largely unknown. Thus, we sought to investigate the possible effects of cannabis use on plasma HIV-1 RNA viral loads among recently-seroconverted illicit drug users. Design and Methods We used data from two linked longitudinal observational cohorts of people who use injection drugs. Using multivariable linear mixed-effects modeling, we analysed the relationship between pVL and high-intensity cannabis use among participants who seroconverted following recruitment. Results Between May, 1996 and March, 2012, 88 individuals seroconverted after recruitment and were included in these analyses. Median pVL in the first 365 days among all seroconverters was 4.66 log10 c/mL. In a multivariable model, at least daily cannabis use was associated with 0.51 log10 c/mL lower pVL (β = −0.51, Standard Error = 0.170, p-value = 0.003). Discussion Consistent with the findings from recent in vitro and in vivo studies, including one conducted among lentiviral-infected primates, we observed a strong association between cannabis use and lower pVL following seroconversion among illicit drug-using participants. Conclusion Our findings support the further investigation of the immunomodulatory or anti-viral effects of cannabinoids among individuals living with HIV/AIDS. PMID:25389027

  20. Exploratory Investigation of Impact Loads During the Forward Handspring Vault

    PubMed Central

    Penitente, Gabriella; Sands, William A.

    2015-01-01

    The purpose of this study was to examine kinematic and kinetic differences in low and high intensity hand support impact loads during a forward handspring vault. A high-speed video camera (500 Hz) and two portable force platforms (500 Hz) were installed on the surface of the vault table. Two-dimensional analyses were conducted on 24 forward handspring vaults performed by 12 senior level, junior Olympic program female gymnasts (16.9 ±1.4 yr; body height 1.60 ±0.1 m; body mass 56.7 ±7.8 kg). Load intensities at impact with the vault table were classified as low (peak force < 0.8 × body weight) and high (peak force > 0.8 × body weight). These vaults were compared via crucial kinetic and kinematic variables using independent t-tests and Pearson correlations. Statistically significant (p < 0.001) differences were observed in peak force (t(24) = 4.75, ES = 3.37) and time to peak force (t(24) = 2.07, ES = 1.56). Statistically significant relationships between the loading rate and time to peak force were observed for high intensity loads. Peak force, time to peak force, and a shoulder angle at impact were identified as primary variables potentially involved in the determination of large repetitive loading rates on the forward handspring vault. PMID:26240649

  1. Acute Hematological and Inflammatory Responses to High-intensity Exercise Tests: Impact of Duration and Mode of Exercise.

    PubMed

    Minuzzi, Luciele G; Carvalho, Humberto M; Brunelli, Diego T; Rosado, Fatima; Cavaglieri, Cláudia R; Gonçalves, Carlos E; Gaspar, Joana M; Rama, Luís M; Teixeira, Ana M

    2017-07-01

    The purpose of this study was to investigate the hematological and inflammatory responses to 4 maximal high-intensity protocols, considering energy expenditure in each test. 9 healthy volunteers performed 4 high-intensity exercise tests of short [Wingate (WANT); Repeated-sprints (RSA)] and long durations [Continuous VO2 test (VCONT); intermittent VO2 test (VINT)] in a cycle-ergometer, until exhaustion. Hematological parameters and IL-6, IL-10 and creatine kinase (CK) levels were determined before (PRE), POST, 30 min, 1, 2, 12 and 24 h after the end of the protocols. Additionally, energy expenditure was determined. Leucocytes, erythrocytes and lymphocytes increased at POST and returned to PRE values at 30 min for all protocols. Lymphocytes had a second decreased at 2 h and granulocytes increased at 2 h when compared to PRE. Both variables returned to PRE values between 12-24 h into recovery. The magnitude of response for IL-6 was greater in VINT and for IL-10 in VCONT. There was no association of energy expenditure within each exercise protocol with the pattern of IL-6, IL-10 and CK responses to the exercise protocols. The present finding support that similar responses after continuous or intermittent acute protocols are observed when exercises are performed to volitional failure, regardless of the duration and mode of exercise. © Georg Thieme Verlag KG Stuttgart · New York.

  2. Impact of high-intensity pulsed electric fields on bioactive compounds in Mediterranean plant-based foods.

    PubMed

    Elez-Martínez, Pedro; Soliva-Fortuny, Robert; Martín-Belloso, Olga

    2009-05-01

    Novel non-thermal processing technologies such as high-intensity pulsed electric field (HIPEF) treatments may be applied to pasteurize plant-based liquid foods as an alternative to conventional heat treatments. In recent years, there has been an increasing interest in HIPEF as a way of preserving and extending the shelf-life of liquid products without the quality damage caused by heat treatments. However, less attention has been paid to the effects of HIPEF on minor constituents of these products, namely bioactive compounds. This review is a state-of-the-art update on the effects of HIPEF treatments on health-related compounds in plants of the Mediterranean diet such as fruit juices, and Spanish gazpacho. The relevance of HIPEF-processing parameters on retaining plant-based bioactive compounds will be discussed.

  3. High Intensity Polarized Electron Gun

    SciTech Connect

    Redwine, Robert P.

    2012-07-31

    The goal of the project was to investigate the possibility of building a very high intensity polarized electron gun for the Electron-Ion Collider. This development is crucial for the eRHIC project. The gun implements a large area cathode, ring-shaped laser beam and active cathode cooling. A polarized electron gun chamber with a large area cathode and active cathode cooling has been built and tested. A preparation chamber for cathode activation has been built and initial tests have been performed. Major parts for a load-lock chamber, where cathodes are loaded into the vacuum system, have been manufactured.

  4. The impact of water-floating and high-intensity exercise on rat's HPA axis and interleukins concentrations.

    PubMed

    Wang, Jian; Zhao, Dan; Li, Jie; Wang, Guohong; Hu, Lanping; Shao, Jiaging; Gu, Ping; Du, Hong; Wang, Yangt

    2012-09-01

    Our studies explore the changes of blood corticosterone (CORT), adrenocorticotropic hormone (ACTH), interleukin (IL)-1β, IL-2, IL-6 concentrations and the pituitary ACTH expression in rats after water floating in the presence or absence of following high-intensity exercise. The rats were randomly assigned into three groups. Group A served as control; Group B received 180 minutes water floating and psychological (fear) stimulation; Group C received the same treatment as Group B in addition and 120-minutes non-stop running. Compared to Group A, Group B showed a significant increase of IL-2 (19.91 ± 2.52 vs. 13.09 ± 3.13 ng/ml, P < 0.05), and IL-6 (0.18 ± 0.08 vs. 0.12 ± 0.05 ng/ml, P < 0.05); Group C demonstrated a significant increase of CORT (977.22 ± 207.36 ng/ml vs. 434.58 ± 110.45 ng/ml, P <0.01) and IL-1β (0.21 ± 0.04 vs. 0.16 ± 0.06 ng/ml, P < 0.05), IL-2 (20.29 ± 4.23 vs. 13.09 ± 3.13 ng/ml, P < 0.05), and IL-6 (0.19 ± 0.03 vs. 0.12 ± 0.05 ng/ml, P < 0.05) levels, and a significant decrease of ACTH (16.95 ± 5.46 vs. 22.96 ± 7.32 pg/ml, P = 0.03). Immunohistochemical staining showed the decreased number of pituitary ACTH-positive cells in both Groups B and C (P < 0.05) as compared to Group A. These results have lead us to believe that acute psychological stress can activate the pituitary-adrenal axis and lead to elevation of serum IL-2, IL-6 concentrations. Combined with high-intensity exercise, it can result in the increase of serum CORT, IL-1β, IL-2, IL-6 levels, and the suppression of ACTH.

  5. Impact of High-intensity Intermittent and Moderate-intensity Continuous Exercise on Autonomic Modulation in Young Men.

    PubMed

    Cabral-Santos, C; Giacon, T R; Campos, E Z; Gerosa-Neto, J; Rodrigues, B; Vanderlei, L C M; Lira, F S

    2016-06-01

    The aim of this study was to compare heart rate variability (HRV) recovery after two iso-volume (5 km) exercises performed at different intensities. 14 subjects volunteered (25.17±5.08 years; 74.7±6.28 kg; 175±0.05 cm; 59.56±5.15 mL·kg(-1)·min(-1)) and after determination of peak oxygen uptake (VO2Peak) and the speed associated with VO2Peak (sVO2Peak), the subjects completed 2 random experimental trials: high-intensity exercise (HIE - 1:1 at 100% sVO2Peak), and moderate-intensity continuous exercise (MIE - 70% sVO2Peak). HRV and RR intervals were monitored before, during and after the exercise sessions together with, the HRV analysis in the frequency domains (high-frequency - HF: 0.15 to 0.4 Hz and low-frequency - LF: 0.04 to 0.15 Hz components) and the ratio between them (LF/HF). Statistical analysis comparisons between moments and between HIE and MIE were performed using a mixed model. Both exercise sessions modified LFlog, HFlog, and LF/HF (F=16.54, F=19.32 and F=5.17, p<0.05, respectively). A group effect was also found for LFlog (F=23.91, p<0.05), and HFlog (F=57.55, p< 0.05). LF/HF returned to resting value 15 min after MIE exercise and 20 min after HIE exercise. This means that the heavy domain (aerobic and anaerobic threshold) induces dissimilar autonomic modification in physically active subjects. Both HIE and MIE modify HRV, and generally HIE delays parasympathetic autonomic modulation recovery after iso-volume exercise.

  6. High intensity hadron accelerators

    SciTech Connect

    Teng, L.C.

    1989-05-01

    This rapporteur report consists mainly of two parts. Part I is an abridged review of the status of all High Intensity Hadron Accelerator projects in the world in semi-tabulated form for quick reference and comparison. Part II is a brief discussion of the salient features of the different technologies involved. The discussion is based mainly on my personal experiences and opinions, tempered, I hope, by the discussions I participated in in the various parallel sessions of the workshop. In addition, appended at the end is my evaluation and expression of the merits of high intensity hadron accelerators as research facilities for nuclear and particle physics.

  7. High intensity neutrino beams

    SciTech Connect

    Ichikawa, A. K.

    2015-07-15

    High-intensity proton accelerator complex enabled long baseline neutrino oscillation experiments with a precisely controlled neutrino beam. The beam power so far achieved is a few hundred kW with enourmorous efforts of accelerator physicists and engineers. However, to fully understand the lepton mixing structure, MW-class accelerators are desired. We describe the current intensity-frontier high-energy proton accelerators, their plans to go beyond and technical challenges in the neutrino beamline facilities.

  8. Wheelchair caster loading during frontal impact.

    PubMed

    Bertocci, Gina E; van Roosmalen, Linda

    2003-01-01

    Many wheelchair users are required or choose to use their wheelchairs as a motor vehicle seat during transport. It is therefore key that the wheelchair components be designed to tolerate crash-level loading conditions. Casters are particularly prone to failure under crash loading conditions. Our study evaluated wheelchair caster loading during 20g/48 kph frontal sled impact testing using an 85-kg surrogate wheelchair base (SWCB) with casters positioned on a load-measuring platform. A Hybrid III 50th percentile male test dummy was seated in the SWCB, which simulated a power wheelchair and was secured using four-point tiedowns. Various rear securement point heights and wheelchair seating systems were used to study their effect on caster loading. Caster normal loading was found to vary from 769 to 7,209 N depending on rear securement location and integrity of the seating system. Dynamic sled impact test results showed that normal loading of the front wheelchair casters was influenced by wheelchair seating system integrity and rear wheelchair securement height. Shear loading varied from 781 to 1,589 N and did not appear to be dependent on seat integrity or rear securement height. The load/time histories measured during dynamic impact testing can be used to guide the development of transit-safe caster design.

  9. Greater impact of acute high-intensity interval exercise on post-exercise executive function compared to moderate-intensity continuous exercise.

    PubMed

    Tsukamoto, Hayato; Suga, Tadashi; Takenaka, Saki; Tanaka, Daichi; Takeuchi, Tatsuya; Hamaoka, Takafumi; Isaka, Tadao; Hashimoto, Takeshi

    2016-03-01

    Aerobic moderate-intensity continuous exercise (MCE) can improve executive function (EF) acutely, potentially through the activation of both physiological and psychological factors. Recently, high-intensity interval exercise (HIIE) has been reported to be more beneficial for physical adaptation than MCE. Factors for EF improvement can potentially be more enhanced by HIIE than by MCE; but the effects of HIIE on EF remain unknown. Therefore, we aimed to examine to what extent HIIE impacts post-exercise EF immediately after exercise and during post-exercise recovery, compared with traditional MCE. Twelve healthy male subjects performed cycle ergometer exercise based on either HIIE or MCE protocols in a randomized and counterbalanced order. The HIIE protocol consisted of four 4-min bouts at 90% of peak VO2 with 3-min active recovery at 60% of peak VO2. A volume-matched MCE protocol was applied at 60% of peak VO2. To evaluate EF, a color-words Stroop task was performed pre- and post-exercise. Improvement in EF immediately after exercise was the same for the HIIE and MCE protocols. However, the improvement of EF by HIIE was sustained during 30 min of post-exercise recovery, during which MCE returned to the pre-exercise level. The EF response in the post-exercise recovery was associated with changes in physiological and psychological responses. The present findings showed that HIIE and MCE were capable of improving EF. Moreover, HIIE could prolong improvement in EF during post-exercise recovery. For the first time, we suggest that HIIE may be more effective strategy than MCE for improving EF.

  10. High intensity solar cell radiometer

    NASA Technical Reports Server (NTRS)

    Brandhorst, H. W.; Spisz, E. W.

    1972-01-01

    Device can be employed under high intensity illumination conditions such as would occur in a close-solar-approach space mission or in monitoring high intensity lamps. Radiometer consists of silicon solar cells with thin semi-transparent coatings of aluminum deposited on the front surfaces to permit transmission of small percentage of light and reflect the remainder.

  11. Cardiometabolic risk markers, adipocyte fatty acid binding protein (aFABP) and the impact of high-intensity interval training (HIIT) in obese adolescents.

    PubMed

    Blüher, Susann; Käpplinger, Jakob; Herget, Sabine; Reichardt, Sandra; Böttcher, Yvonne; Grimm, Andrea; Kratzsch, Jürgen; Petroff, David

    2017-03-01

    The impact of high-intensity interval training (HIIT) as well as the association between the adipocyte fatty binding protein (aFABP) and cardiometabolic risk factors in overweight adolescents was investigated. Twenty-eight adolescents (13-18years; BMI≥90th percentile according to German reference values) were offered HIIT twice weekly for 6months. At baseline and after program completion, anthropometric, clinical and metabolic characteristics were assessed and a fasting blood sample was obtained. Leptin, adiponectin, visfatin and aFABP were measured using commercially available kits. DNA methylation at RALBP1 was assessed using pyrosequencing. Descriptive statistics, Pearson's correlation and linear models were calculated. Mean age at start of the program was 15.5±1.4years (53.5% females) and 20/28 (71%) provided follow-up data. At baseline, aFABP was correlated with BMI-SDS (0.48 [0.13,0.72]; p=0.0095), waist-to-height-ratio (0.63 [0.33,0.81], p=0.00036) and body fat content (0.55 [0.21, 0.77]; p=0.0031). Certain markers of metabolic risk were significantly correlated with aFABP (HOMA-IR 0.52 [0.19, 0.75], p=0.0044; γGT 0.48 [0.13, 0.73], p=0.0091; uric acid 0.46 [0.11, 0.71] p=0.013; HDL-C -0.39 [-0.66, -0.01] p=0.043; triglycerides 0.38 [0.01, 0.66], p=0.047). With the exception of triglycerides, these associations vanished after adjusting for BMI-SDS. aFABP did not depend on sex, age or pubertal stage in obese adolescents. After the HIIT program, small but significant reductions were observed in waist-to-height-ratio, (0.013 [0.0025, 0.024]; p=0.023), skin-fold based body fat content (2.0% [0.6, 3.5]; p=0.011), and standard deviation score of systolic blood pressure (0.69 [0.26 to 1.1]; p=0.0036). No changes were observed in adipokines or epigenetic markers following the program. HIIT may have beneficial effects on body composition and cardiometabolic health in overweight adolescents. Like in adults, aFABP seems to be associated with markers of metabolic

  12. Differential Impact of Acute High-Intensity Exercise on Circulating Endothelial Microparticles and Insulin Resistance between Overweight/Obese Males and Females

    PubMed Central

    Durrer, Cody; Robinson, Emily; Wan, Zhongxiao; Martinez, Nic; Hummel, Michelle L.; Jenkins, Nathan T.; Kilpatrick, Marcus W.; Little, Jonathan P.

    2015-01-01

    Background An acute bout of exercise can improve endothelial function and insulin sensitivity when measured on the day following exercise. Our aim was to compare acute high-intensity continuous exercise (HICE) to high-intensity interval exercise (HIIE) on circulating endothelial microparticles (EMPs) and insulin sensitivity in overweight/obese men and women. Methods Inactive males (BMI = 30 ± 3, 25 ± 6 yr, n = 6) and females (BMI = 28 ± 2, 21 ± 3 yr, n = 7) participated in three experimental trials in a randomized counterbalanced crossover design: 1) No exercise control (Control); 2) HICE (20 min cycling @ just above ventilatory threshold); 3) HIIE (10 X 1-min @ ∼90% peak aerobic power). Exercise conditions were matched for external work and diet was controlled post-exercise. Fasting blood samples were obtained ∼18 hr after each condition. CD62E+ and CD31+/CD42b- EMPs were assessed by flow cytometry and insulin resistance (IR) was estimated by homeostasis model assessment (HOMA-IR). Results There was a significant sex X exercise interaction for CD62E+ EMPs, CD31+/CD42b- EMPs, and HOMA-IR (all P<0.05). In males, both HICE and HIIE reduced EMPs compared to Control (P≤0.05). In females, HICE increased CD62E+ EMPs (P<0.05 vs. Control) whereas CD31+/CD42b- EMPs were unaltered by either exercise type. There was a significant increase in HOMA-IR in males but a decrease in females following HIIE compared to Control (P<0.05). Conclusions Overweight/obese males and females appear to respond differently to acute bouts of high-intensity exercise. A single session of HICE and HIIE reduced circulating EMPs measured on the morning following exercise in males but in females CD62E+ EMPs were increased following HICE. Next day HOMA-IR paradoxically increased in males but was reduced in females following HIIE. Future research is needed to investigate mechanisms responsible for potential differential responses between males and females. PMID:25710559

  13. Impact of high-intensity pulsed electric fields on carotenoids profile of tomato juice made of moderate-intensity pulsed electric field-treated tomatoes.

    PubMed

    Vallverdú-Queralt, Anna; Odriozola-Serrano, Isabel; Oms-Oliu, Gemma; Lamuela-Raventós, Rosa M; Elez-Martínez, Pedro; Martín-Belloso, Olga

    2013-12-01

    The effect of pulsed electric fields (PEF) on the carotenoid content of tomato juices was studied. First, moderate-intensity PEF (MIPEF) was applied to raw tomatoes. Afterwards, MIPEF-treated and untreated tomatoes were immediately refrigerated at 4 °C for 24 h and then, they were separately ground to produce tomato juices. Juices were treated by heat treatments or by high-intensity PEF (HIPEF) and stored under refrigeration for 56 days. MIPEF treatment of tomatoes increased the content of carotenoid compounds in tomato juices. An enhancement of 63-65% in 15-cis-lycopene was observed in juices prepared with MIPEF-treated tomatoes. A slight increase in cis-lycopene isomers was observed over time, whereas other carotenoids slightly decreased. However, HIPEF treated tomato juices maintained higher carotenoid content (10-20%) through the storage time than thermally and untreated juices. The combination of MIPEF and HIPEF treatments could be used not only to produce tomato juices with high carotenoid content but also, to maintain higher the carotenoid content during storage time.

  14. Impact of long-term high-intensity interval and moderate-intensity continuous training on subclinical inflammation in overweight/obese adults.

    PubMed

    Gerosa-Neto, José; Antunes, Barbara M M; Campos, Eduardo Z; Rodrigues, Jhennyfer; Ferrari, Gustavo D; Rosa Neto, José C; Bueno, Carlos R; Lira, Fábio S

    2016-12-01

    Obesity is a risk factor able to trigger several inflammatory alterations and the imbalance between pro- and anti-inflammatory cytokine productions. Physical exercise is an important strategy for reduction of inflammatory established process. The aim of this study was to evaluate the effect of 16 weeks of three exercise training programs in the inflammatory profile and insulin resistance in overweight/obesity. Thirty two men and women (46.4±10.1 years; 162.0±9.1 cm; 82.0±13.6 kg) were divided into three groups for training on a treadmill: continuous at 70% maximum heart rate (HRmax) 5 times a week (CONT); 1×4 min (1-bout) and 4×4 min (high intensity interval training, HIIT) at 90% HRmax 3 times a week. Interleukin (IL) 6 and IL-10, tumor necrosis factor-alpha (TNF-α), insulin and adiponectin levels were analyzed by enzyme-linked immunosorbent assay, and homeostasis model assessment insulin resistance was calculated. After 16 weeks of training blood concentrations of IL-6 decreased in the HIIT group (P=0.035), TNF-α decreased in the CONT (P=0.037) and increased in HIIT (P=0.001) and adiponectin decreased in the three training models. There was a trend towards decreased body weight and body mass index (BMI) after HIIT only (P=0.059 and P=0.060, respectively). Despite the decrease of adiponectin and the increase of TNF-α in HIIT group, insulin sensitivity showed a trend for improvement (P=0.08). HIIT program decreased IL-6 at rest and although not significant was the only who tended to decrease total body weight and BMI. Taken together, our data suggest that both HIIT as well as CONT exercises training program promotes changes in inflammatory profile in overweight/obesity, but dissimilar response is seen in TNF-α levels.

  15. High intensity focused ultrasound with Focal-One(®) device: Prostate-specific antigen impact and morbidity evaluation during the initial experience.

    PubMed

    Perez-Reggeti, J I; Sanchez-Salas, R; Sivaraman, A; Linares Espinos, E; de Gracia-Nieto, A E; Barret, E; Galiano, M; Rozet, F; Fregeville, A; Renard-Penna, R; Cathala, N; Mombet, A; Prapotnich, D; Cathelineau, X

    2016-12-01

    We report our initial experience in the treatment of prostate cancer (PCa) with high-intensity focused ultrasound (HIFU) using the Focal-One(®) device. Retrospective review of the prospectively populated database. Between June 2014 to October 2015, 85 patients underwent HIFU (focal/whole-gland) treatment for localized PCa. Preoperative cancer localization was done with multiparametric magnetic resonance imaging (mpMRI) and transperineal mapping biopsies. Treatment was carried out using the Focal-One(®) device under general anesthesia. Oncological follow-up: PSA measurement and control biopsy with mpMRI according to protocol. Questionnaire-based functional outcome assessment was done. Complications were reported using Clavien classification. The median PSA was 7.79ng/ml (IQR 6.32-9.16), with a median prostate volume of 38cc (IQR: 33-49.75). Focal and whole-gland therapy was performed in 64 and 21 patients respectively. Ten patients received salvage HIFU. Complications were encountered in 15% of cases, all Clavien 2 graded. Mean hospital stay was 1.8 days (0-7) and bladder catheter was removed on day 2 (1-6). Mean percentage reduction of PSA was 54%. Median follow-up was 3 months (IQR: 2-8). Functional outcomes: All patients were continents at 3 months and potency was maintained in 83% of the preoperatively potent. Focal-One(®) HIFU treatment appears to be a safe procedure with few complications. Functional outcomes proved no urinary incontinence and sexual function were maintained in 83%. Copyright © 2016. Publicado por Elsevier España, S.L.U.

  16. Age related vascular endothelial function following lifelong sedentariness: positive impact of cardiovascular conditioning without further improvement following low frequency high intensity interval training.

    PubMed

    Grace, Fergal M; Herbert, Peter; Ratcliffe, John W; New, Karl J; Baker, Julien S; Sculthorpe, Nicholas F

    2015-01-01

    Aging is associated with diffuse impairments in vascular endothelial function and traditional aerobic exercise is known to ameliorate these changes. High intensity interval training (HIIT) is effective at improving vascular function in aging men with existing disease, but its effectiveness remains to be demonstrated in otherwise healthy sedentary aging. However, the frequency of commonly used HIIT protocols may be poorly tolerated in older cohorts. Therefore, the present study investigated the effectiveness of lower frequency HIIT (LfHIIT) on vascular function in a cohort of lifelong sedentary (SED; n = 22, age 62.7 ± 5.2 years) men compared with a positive control group of lifelong exercisers (LEX; n = 17, age 61.1 ± 5.4 years). The study consisted of three assessment phases; enrolment to the study (Phase A), following 6 weeks of conditioning exercise in SED (Phase B) and following 6 weeks of low frequency HIIT in both SED and LEX (LfHIIT; Phase C). Conditioning exercise improved FMD in SED (3.4 ± 1.5% to 4.9 ± 1.1%; P < 0.01) such that the difference between groups on enrolment (3.4 ± 1.5% vs. 5.3 ± 1.4%; P < 0.01) was abrogated. This was maintained but not further improved following LfHIIT in SED whilst FMD remained unaffected by LfHIIT in LEX. In conclusion, LfHIIT is effective at maintaining improvements in vascular function achieved during conditioning exercise in SED. LfHIIT is a well-tolerated and effective exercise mode for reducing cardiovascular risk and maintaining but does not improve vascular function beyond that achieved by conditioning exercise in aging men, irrespective of fitness level.

  17. Impact of long-term high-intensity interval and moderate-intensity continuous training on subclinical inflammation in overweight/obese adults

    PubMed Central

    Gerosa-Neto, José; Antunes, Barbara M.M.; Campos, Eduardo Z.; Rodrigues, Jhennyfer; Ferrari, Gustavo D.; Rosa Neto, José C.; Bueno, Carlos R.; Lira, Fábio S.

    2016-01-01

    Obesity is a risk factor able to trigger several inflammatory alterations and the imbalance between pro- and anti-inflammatory cytokine productions. Physical exercise is an important strategy for reduction of inflammatory established process. The aim of this study was to evaluate the effect of 16 weeks of three exercise training programs in the inflammatory profile and insulin resistance in overweight/obesity. Thirty two men and women (46.4±10.1 years; 162.0±9.1 cm; 82.0±13.6 kg) were divided into three groups for training on a treadmill: continuous at 70% maximum heart rate (HRmax) 5 times a week (CONT); 1×4 min (1-bout) and 4×4 min (high intensity interval training, HIIT) at 90% HRmax 3 times a week. Interleukin (IL) 6 and IL-10, tumor necrosis factor-alpha (TNF-α), insulin and adiponectin levels were analyzed by enzyme-linked immunosorbent assay, and homeostasis model assessment insulin resistance was calculated. After 16 weeks of training blood concentrations of IL-6 decreased in the HIIT group (P=0.035), TNF-α decreased in the CONT (P=0.037) and increased in HIIT (P=0.001) and adiponectin decreased in the three training models. There was a trend towards decreased body weight and body mass index (BMI) after HIIT only (P=0.059 and P=0.060, respectively). Despite the decrease of adiponectin and the increase of TNF-α in HIIT group, insulin sensitivity showed a trend for improvement (P=0.08). HIIT program decreased IL-6 at rest and although not significant was the only who tended to decrease total body weight and BMI. Taken together, our data suggest that both HIIT as well as CONT exercises training program promotes changes in inflammatory profile in overweight/obesity, but dissimilar response is seen in TNF-α levels. PMID:28119880

  18. Age related vascular endothelial function following lifelong sedentariness: positive impact of cardiovascular conditioning without further improvement following low frequency high intensity interval training

    PubMed Central

    Grace, Fergal M.; Herbert, Peter; Ratcliffe, John W.; New, Karl J.; Baker, Julien S.; Sculthorpe, Nicholas F.

    2015-01-01

    Abstract Aging is associated with diffuse impairments in vascular endothelial function and traditional aerobic exercise is known to ameliorate these changes. High intensity interval training (HIIT) is effective at improving vascular function in aging men with existing disease, but its effectiveness remains to be demonstrated in otherwise healthy sedentary aging. However, the frequency of commonly used HIIT protocols may be poorly tolerated in older cohorts. Therefore, the present study investigated the effectiveness of lower frequency HIIT (LfHIIT) on vascular function in a cohort of lifelong sedentary (SED; n =22, age 62.7 ± 5.2 years) men compared with a positive control group of lifelong exercisers (LEX; n = 17, age 61.1 ± 5.4 years). The study consisted of three assessment phases; enrolment to the study (Phase A), following 6 weeks of conditioning exercise in SED (Phase B) and following 6 weeks of low frequency HIIT in both SED and LEX (LfHIIT; Phase C). Conditioning exercise improved FMD in SED (3.4 ± 1.5% to 4.9 ± 1.1%; P <0.01) such that the difference between groups on enrolment (3.4 ± 1.5% vs. 5.3 ± 1.4%; P <0.01) was abrogated. This was maintained but not further improved following LfHIIT in SED whilst FMD remained unaffected by LfHIIT in LEX. In conclusion, LfHIIT is effective at maintaining improvements in vascular function achieved during conditioning exercise in SED. LfHIIT is a well‐tolerated and effective exercise mode for reducing cardiovascular risk and maintaining but does not improve vascular function beyond that achieved by conditioning exercise in aging men, irrespective of fitness level. PMID:25626864

  19. Trauma of lung due to impact load.

    PubMed

    Yen, R T; Fung, Y C; Liu, S Q

    1988-01-01

    A quantitative evaluation of lung injury due to impact loading is of general interest. Hemorrhage and edema are the usual sequelae to traumatic pulmonary impact. To gain some quantitative understanding of the phenomena, we perfused excised rabbit lung with Macrodex at isogravimetric condition and monitored lung weight continuously after impact. It is shown that a factor of importance is the rigidity of the surface on which the lung rests. The rate of lung weight increase is smaller if the lung was 'freely' supported on a soft cloth, more if it was supported on a rigid plate. This suggests the influence of stress wave reflection. The critical condition correlates with the initial velocity of impact at the surface of the lung, or with the maximum deflection. For a freely supported lung, the rate of lung weight increase was 22% of the initial total lung weight per h after impact when the impact velocity was 11.5 ms-1, 30% when the velocity was 13.2 ms-1, several 100% at 13.5 ms-1, signaling massive lung injury. Since the velocity of sound in rabbit lung is 33.3 ms-1 when the inflation (transpulmonary) pressure is 10 cm H2O, the critical velocity of 13.5 ms-1 corresponds to a Mach number of 0.4. The maximum surface displacement of the lung is almost linearly proportional to the initial velocity of impact. The exact cause of edema and hemorrhage is unknown; we hypothesize that it is due to tensile stress in the alveolar wall caused by the impact.

  20. Impact of low-volume, high-intensity interval training on maximal aerobic capacity, health-related quality of life and motivation to exercise in ageing men.

    PubMed

    Knowles, Ann-Marie; Herbert, Peter; Easton, Chris; Sculthorpe, Nicholas; Grace, Fergal M

    2015-01-01

    There is a demand for effective training methods that encourage exercise adherence during advancing age, particularly in sedentary populations. This study examined the effects of high-intensity interval training (HIIT) exercise on health-related quality of life (HRQL), aerobic fitness and motivation to exercise in ageing men. Participants consisted of males who were either lifelong sedentary (SED; N = 25; age 63 ± 5 years) or lifelong exercisers (LEX; N = 19; aged 61 ± 5 years). [Formula: see text] and HRQL were measured at three phases: baseline (Phase A), week seven (Phase B) and week 13 (Phase C). Motivation to exercise was measured at baseline and week 13. [Formula: see text] was significantly higher in LEX (39.2 ± 5.6 ml kg min(-1)) compared to SED (27.2 ± 5.2 ml kg min(-1)) and increased in both groups from Phase A to C (SED 4.6 ± 3.2 ml kg min(-1), 95 % CI 3.1 - 6.0; LEX 4.9 ± 3.4 ml kg min(-1), 95 % CI 3.1-6.6) Physical functioning (97 ± 4 LEX; 93 ± 7 SED) and general health (70 ± 11 LEX; 78 ± 11 SED) were significantly higher in LEX but increased only in the SED group from Phase A to C (physical functioning 17 ± 18, 95 % CI 9-26, general health 14 ± 14, 95 % CI 8-21). Exercise motives related to social recognition (2.4 ± 1.2 LEX; 1.5 ± 1.0 SED), affiliation (2.7 ± 1.0 LEX; 1.6 ± 1.2 SED) and competition (3.3 ± 1.3 LEX; 2.2 ± 1.1) were significantly higher in LEX yet weight management motives were significantly higher in SED (2.9 ± 1.1 LEX; 4.3 ± 0.5 SED). The study provides preliminary evidence that low-volume HIIT increases perceptions of HRQL, exercise motives and aerobic capacity in older adults, to varying degrees, in both SED and LEX groups.

  1. Application of laser, holographic, nondestructive testing by impact loading.

    PubMed

    Wang, J; Grant, I

    1995-07-01

    A description of research on holographic, nondestructive testing (HNDT) with impact loading is presented to demonstrate the technique as a practical HNDT method. The advantages of impact, or impulse, loading coupled with pulsed-laser illumination for HNDT away from the laboratory are discussed. The effect of the loading position, exposure timing, and prestressing on test results is discussed in detail. Experimental verification of the appropriateness of pulsed-laser HNDT in the testing of honeycomb materials by using impact loading is discussed.

  2. Delaminations in composite plates under impact loads

    NASA Technical Reports Server (NTRS)

    Finn, Scott R.; Springer, George S.

    1991-01-01

    A method is presented for calculating the locations, shapes, and sizes of delaminations which occur in a fiber reinforced composite plate subjected to non-penetrating (low velocity) impact of a solid object. The plate may be simply supported, clamped, or free along its edges. A failure model of the delamination formation was developed. This model was then coupled with a finite element analysis. The model and the finite element analysis were then implemented by a computer code (IMPACT-ST) which can be used to estimate the damage initiation load and the locations, shapes, and sizes of the delaminations. Tests were performed measuring the geometries of the delaminations in graphite-epoxy, graphite-toughened epoxy, and graphite-PEEK plates impacted by a projectile with a spherical tip having masses ranging from 0.355 lbm to 0.963 lbm and velocities from 50 in/sec to 225 in/sec. The data were compared to the results of the model, and good agreements were found between the measured and the calculated delamination lengths and widths.

  3. Impacts of converting low-intensity pastureland to high-intensity bioenergy cropland on the water quality of tropical streams in Brazil.

    PubMed

    Taniwaki, Ricardo Hideo; Cassiano, Carla Cristina; Filoso, Solange; Ferraz, Silvio Frosini de Barros; Camargo, Plínio Barbosa de; Martinelli, Luiz Antônio

    2017-04-15

    In Brazil, the cultivation of bioenergy crops is expanding at an accelerated rate. Most of this expansion has occurred over low-intensity pasture and is considered sustainable because it does not involve deforestation of natural vegetation. However, the impacts on the water quality of headwater streams are poorly understood, especially with regard to the influence of land use patterns in the watershed. In this study, we investigated the effects of land-use conversion on the water quality of streams draining sugarcane fields and examined whether the preservation of forested areas at the top of the headwaters would help mitigate the negative impacts of intensive agriculture. Water samples were collected in two paired catchments in southeastern Brazil, which is one of the largest sugarcane production regions in the world. Our results show significant differences in the water quality of streams predominantly draining the pasture or the sugarcane field. Several parameters commonly used to indicate water quality, such as the concentrations of nitrate and suspended solids, were significantly higher in the sugarcane than in the pasture stream. Differences in water quality between the streams draining predominantly pasture or sugarcane fields were accentuated during the wet season. The preservation of forests surrounding the headwater streams was associated with overall better water quality conditions, such as lower nitrate concentrations and temperature of the stream water. We concluded that forest conservation in the headwater agricultural catchments is an important factor preventing water quality degradation in tropical streams. Therefore, we strongly recommend the preservation of robust riparian forests in the headwaters of tropical watersheds with intensive agriculture. More studies on the effects of best agricultural practices in bioenergy crops can greatly improve our capacity to prevent the degradation of water quality in the tropical waterways as intensive

  4. High intensity portable fluorescent light

    NASA Technical Reports Server (NTRS)

    Kendall, F. B.

    1972-01-01

    Eight high intensity portable fluorescent lights were produced. Three prototype lights were also produced, two of which were subsequently updated to the physical and operational configuration of the qualification and flight units. Positioning of lamp apertures and reflectors in these lights is such that the light is concentrated and intensified in a specific pattern rather than widely diffused. Indium amalgam control of mercury vapor pressure in the lamp gives high output at lamp ambient temperatures up to 105 C. A small amount of amalgam applied to each electrode stem helps to obtain fast warm-up. Shrinking a Teflon sleeve on the tube and potting metal caps on each end of the lamp minimizes dispersion of mercury vapor and glass particles in the event of accidental lamp breakage. Operation at 20 kHz allows the lamps to consume more power than at low frequency, thus increasing their light output and raising their efficiency. When used to expose color photographic film, light from the lamps produces results approximately equal to sunlight.

  5. Lightly loaded lubricated impacts: Idle gear rattle

    NASA Astrophysics Data System (ADS)

    Tangasawi, O.; Theodossiades, S.; Rahnejat, H.

    2007-12-01

    Idle gear rattle is associated with the characteristic noise that unselected impacting gears radiate to the environment. It is induced by engine order vibration in the presence of backlash in the unengaged gear pairs, resulting in oscillatory response within their backlash range. A tribo-dynamic model of a front wheel drive manual transmission has been developed to study idle rattle, considering the hydrodynamic contact film reaction and flank friction. The model includes the torsional motions of the idle gears and the lateral motions of the supporting output shafts. The hydrodynamic lubricant film formed between the gear teeth under light impact loads behaves as a nonlinear spring-damper mechanism, whilst the inclusion of the shafts' bearing compliances introduces additional nonlinear terms, which are modelled as piecewise linear functions. The aim of the paper is to extend the existing methodology reported by the authors on idle rattle investigations of geared lubricated systems, based on torsional vibrations only, by considering the system response, which is eventually transferred to the gearbox case through the bearings. These are preliminary results found, which conform closely to experimental measurements taken from a vehicle equipped with a manual transmission of the same type.

  6. The effect of progressive high-intensity inspiratory muscle training and fixed high-intensity inspiratory muscle training on the asymmetry of diaphragm thickness in stroke patients.

    PubMed

    Jung, Ju-Hyeon; Kim, Nan-Soo

    2015-10-01

    [Purpose] This study investigated the effects of progressive load and fixed load high-intensity inspiratory muscle training on the asymmetry of diaphragm thickness in stroke patients. [Subjects] Twenty-one stroke patients were assigned to one of three groups: progressive load high-intensity inspiratory muscle training (n = 8), fixed load high-intensity inspiratory muscle training (n = 6), and controls (n = 7). [Methods] The progressive load and fixed load high-intensity inspiratory muscle training participants undertook an exercise program for 20 minutes, three times weekly, for 6 weeks. After each session, diaphragm thickness was measured using ultrasonography. The diaphragm asymmetry ratio and diaphragm thickening ratio were standardized using a formula. [Results] After intervention, the diaphragm asymmetry ratio significantly differed among the three groups, and the diaphragm asymmetry ratio significantly increased in the control group. A significant increase was identified in the diaphragm thickening ratio within the progressive load and fixed load high-intensity inspiratory muscle training groups. [Conclusion] Progressive load and fixed load high-intensity inspiratory muscle training decreased the asymmetry of diaphragm thickness in stroke patients; this effect, in turn, increased the diaphragm thickening ratio in stroke patients. The two interventions examined here should be selectively applied to individuals in the clinical field.

  7. Dynamic buckling of stiffened plates subjected to explosion impact loads

    NASA Astrophysics Data System (ADS)

    Wang, J.; Guo, J.; Yao, X. L.; Zhang, A. M.

    2017-01-01

    The dynamic buckling characteristics and criteria of a ship's structural stiffened plate subjected to underwater explosion impact loads are investigated in this study. Using the structural deformations observed in the experiments of underwater explosions against a plated grillage model, the mode shapes of the dynamic buckling were obtained. Through the construction of a computational model of stiffened plates subjected to an underwater explosion shock wave, the impact load was theoretically calculated and transformed into a rectangular pulse. According to the different response patterns of stiffened plates under different impact loads, a dynamic buckling criterion for the stiffened plates subjected to an explosion shock wave was proposed. Additionally, the static buckling phenomenon in the stiffened plates was analysed based on the minimum excess principle. In combination with the dynamic buckling criterion, the effects of various stiffening configurations on the dynamic and static buckling loads are discussed. The calculation results show that when the equivalent rectangular pulse is 2-3 times that of the static buckling load, the responses of the stiffened plates under the original shock load and the equivalent rectangular pulse are virtually identical. The impact load amplitude is the primary influencing factor in the dynamic buckling of stiffened plates subjected to underwater explosive impact loads. The stiffened plate aspect ratio has a substantial influence on the dynamic load factor. The analytical method and results are presented, which can be used to design stiffened optimum hull structures to enhance the dynamic load carrying capacity to withstand underwater shock damage.

  8. Finite Element Simulations of Composite Vehicle Structures under Impact Loading

    DTIC Science & Technology

    2004-06-08

    heterogeneity and anisotropy within individual laminae and through the laminate thickness, they undergo complex damage process when subjected to impact ...The studies of the damage process of laminated composites subjected to impact loading have been performed both experimentally and computationally...used for impact investigations. Based on the impact energy and absorbed energy and the inspection of the damaged specimens, the damage process can

  9. Load assumptions for the landing impact of seaplanes

    NASA Technical Reports Server (NTRS)

    Taub, Josef

    1931-01-01

    The formula for the impact of floats must include the enlargement factor itself as well as the type of enlargement. The latter is preferably characterized by the change in surface loading. It is shown that the enlargement of a small seaplane generally results in a changed float (or boat) loading as well as wing loading. The conditions of starting stipulate the retention of the float loading when changing from single-float (boat) to twin-float arrangement. This contingency is followed by an increased impact factor in the twin-float type against the otherwise equivalent single-float type.

  10. High Intensity Radiation Laboratory Reverberation Facility

    NASA Technical Reports Server (NTRS)

    1995-01-01

    This photo depicts the interior of the large Reverberation Chamber located in the High Intensity, Radiation Facility (HIRL). These chambers are used to test susceptibility of aircraft avionics systems responses to high intensity radiated fields. These resources include a Gigahertz Transverse Electromagnetic Cell (GTEM), which provides a uniform field of up to 1000V/m from 10 kHz to 18 Ghz.

  11. The use of high-intensity ultrasonics

    NASA Astrophysics Data System (ADS)

    Puskar, A.

    Features of the application of high-intensity ultrasonics are related to intensity measurements of ultrasonic oscillation and high-intensity ultrasonic effects on the resonance system. High-intensity ultrasonics applications in various technologies are considered, taking into account filtration and catalysis, drying, aerosol and hydrosol coagulation, emulsification and dispersion, metal-powder production, ultrasonic liquid degassing, cavitation, ultrasonic cleaning, metallizing and soldering, welding in an ultrasonic field, and ultrasonics in material machining. Other topics considered are related to ultrasonics in the crystallization of metals and alloys, ultrasonics in heat and chemical-heat treatment, safety and hygiene of working with ultrasonic devices, the effect of high-intensity ultrasonics on solids, the properties of materials after prior action of high-intensity ultrasound, the fatigue of materials during high-frequency stressing, and ultrasonic oscillation and material deformation characteristics. The technological exploitation of ultrasound during material forming is also discussed.

  12. Properties of the tibial component regarding impact load.

    PubMed

    Yoshino, Kazunori; Koga, Yoshio; Segawa, Hiroyuki; Ueno, Yuichi; Tanabe, Yuji; Endo, Naoto; Omori, Go

    2004-06-01

    Load transmission through knee prostheses was examined to clarify how the tibial component behaves under dynamic loading conditions. We did Genesis II total knee arthroplasty using sawbones and measured impact load transmission ratios using the split-Hopkinson pressure bar technique. We also measured the polyethylene strain when an impact load was applied using a strain gauge bonded to the anterior surface of the polyethylene. The impact load transmission ratios of metal-backed and all-polyethylene tibial components were less than 4%. Greater load transmission was observed with metal-backed components, which suggests that some of the applied dynamic load is transferred directly to the tibial cortical bone. Increasing polyethylene thickness decreased impact load transmission ratios in both components, which might lower the cancellous bone stresses beneath tibial implants. Greater strain in the tibial component was observed in all-polyethylene components. Increased polyethylene thickness did not significantly decrease the polyethylene strain, probably because of the nonlinear elastic behavior of the polyethylene material. The distant positioning of the strain gauge may, however, have prevented the detection of local contact strains. Recent clinical studies did not confirm our theoretical predictions, suggesting that other factors contribute more significantly to the clinical outcome in current total knee arthroplasty.

  13. Hazards from High Intensity Lamps and Arcs

    NASA Technical Reports Server (NTRS)

    Sliney, D. H.

    1970-01-01

    The principal occupational health problem generally associated with high intensity arc lamps results from exposure of the eye and skin to ultraviolet radiation. Occasionally, the chorioretinal burns are of concern. The eye is generally more susceptible than the skin to injury from high intensity optical radiation sources whether ultraviolet, visible or infrared. Recent developments in technology have shown that some high intensity optical radiation sources which have output parameters greatly different from those encountered in the natural environment present a serious chorioretinal burn hazard.

  14. Hazards from High Intensity Lamps and Arcs

    NASA Technical Reports Server (NTRS)

    Sliney, D. H.

    1970-01-01

    The principal occupational health problem generally associated with high intensity arc lamps results from exposure of the eye and skin to ultraviolet radiation. Occasionally, the chorioretinal burns are of concern. The eye is generally more susceptible than the skin to injury from high intensity optical radiation sources whether ultraviolet, visible or infrared. Recent developments in technology have shown that some high intensity optical radiation sources which have output parameters greatly different from those encountered in the natural environment present a serious chorioretinal burn hazard.

  15. The Scaling of Bird Impact Loads

    DTIC Science & Technology

    1979-06-01

    LABORATORIES AIR FORCE SYSTEMS COMMAND WRIGHT-PATTMRSON AIR FORCE BASE , OHIO 45433 .... a.-•.. .. . . ..- .... -.. . nr- . • - - : . . ._ .. . :• NOTICE When... patented invention that may in any way be related thereto. This report has been reviewed by the Information Office (10) and is releasable to the...PM Universityna ofhnca Dato Rsarh ntiut Dayton,16 Ohio7-1 4546907 ig___Wik nt2001 XIE COSANLING OFrt IRD _IMPAC LOAD WINE!’ EAF Wrios/ht eoaulticlLb, S

  16. Impact of dynamic loads on propulsion integration

    NASA Astrophysics Data System (ADS)

    Seiner, J. M.

    1994-09-01

    Aircraft dynamic loads produced by engine exhaust plumes are examined for a class of military fighter and bomber configurations in model and full scale. The configurations examined are associated with the USAF F-15 and B-1B aircraft, and the US F-18 HARV and ASTOVL programs. The experience gained as a result of these studies is used to formulate a level of understanding concerning this phenomena that could be useful at the preliminary stage of propulsion/airframe design.

  17. Weight knowledge and weight magnitude: impact on lumbosacral loading.

    PubMed

    Farrag, Ahmed T; Elsayed, Walaa H; El-Sayyad, Mohsen M; Marras, William S

    2015-01-01

    Several factors can impact lumbosacral loads during lifting, including weight knowledge and weight magnitude. However, interaction between them has never been tested. This study investigated the interaction effect of these variables on lumbosacral forces and moments. Participants performed symmetrical lifts using three different weights. Weight knowledge involved known and unknown weight conditions. A biologically assisted dynamic model was used to calculate spinal loading parameters. Weight impacted all variables, while knowledge impacted only compression, by a moderate amount (5%), and spinal moments. Lifting a lightweight resulted in a difference of 16% and 7.2% between knowledge conditions for compression and anterior-posterior shear forces, respectively, compared with a negligible difference of < 1% when lifting a heavy weight. Increased spinal loading with light unknown weight can be attributed to increased muscular co-contraction. Weight knowledge is important to consider at low weight levels as it can increase tissue loading to values equivalent to lifting a heavier weight.

  18. THE HIGH INTENSITY SOLAR ENVIRONMENT TEST SYSTEM

    NASA Image and Video Library

    2016-01-15

    TODD SCHNEIDER LOOKS UP FROM WORK AT THE DOOR OF T HE HIGH INTENSITY SOLAR ENVIRONMENT TEST SYSTEM IN BUILDING 4605. SCHNEIDER IS A PHYSICIST IN THE MATERIALS AND PROCESSES DEPARTMENT AT MSFC AND IS PRINCIPAL INVESTIGATOR FOR HISET.

  19. High-Intensity Plasma Glass Melter

    SciTech Connect

    2004-01-01

    Modular high-intensity plasma melter promises improved performance, reduced energy use, and lower emissions. The glass industry has used the same basic equipment for melting glass for the past 100 years.

  20. Impact of the 2013 American College of Cardiology/American Heart Association cholesterol guidelines on the prescription of high-intensity statins in patients hospitalized for acute coronary syndrome or stroke.

    PubMed

    Valentino, Michael; Al Danaf, Jad; Panakos, Andrew; Ragupathi, Loheetha; Duffy, Danielle; Whellan, David

    2016-11-01

    The 2013 American College of Cardiology/American Heart Association cholesterol management guidelines represented a paradigm shift from the National Cholesterol Education Program Adult Treatment Panel III guidelines, replacing low-density lipoprotein cholesterol targets with a risk assessment model to guide statin therapy. Our objectives are to compare provider prescription of high-intensity statin therapy in patients hospitalized with acute coronary syndrome (ACS) or cerebrovascular accident (CVA) before and after the publication of the 2013 cholesterol guidelines, determine potential predictors of high-intensity statin utilization, and identify targets for improvement in cardiovascular risk reduction among these high-risk populations. A single-center retrospective cohort study of 695 patients discharged with a diagnosis of ACS or CVA in the 6months before (n=359) and after (n=336) the release of the 2013 American College of Cardiology/American Heart Association cholesterol guidelines. Patient characteristics were compared using analysis of variance and χ(2) tests. Multivariable logistic regression models were used to assess clinical predictors of provider utilization of high-intensity statins. After the 2013 cholesterol guidelines, the rate of prescribing high-intensity statins was greater for statin-naïve patients compared with those already on statin therapy (odds ratio [OR]0.51, P=.02). Prescription of high-intensity statins was higher for patients with ACS compared with CVA (OR 8.4, P<.001-pre-2013 guidelines; OR 4.5, P<.001-post-2013 guidelines). Prescription of high-intensity statins steadily improved over the study period, significantly among patients with CVA (P<.001). Physicians were more likely to prescribe high-intensity statins in statin-naïve patients as compared with intensifying existing statin therapy, and their prescription pattern was lower after CVA vs ACS. Copyright © 2016 Elsevier Inc. All rights reserved.

  1. High-intensity training in football.

    PubMed

    Iaia, F Marcello; Rampinini, Ermanno; Bangsbo, Jens

    2009-09-01

    This article reviews the major physiological and performance effects of aerobic high-intensity and speed-endurance training in football, and provides insight on implementation of individual game-related physical training. Analysis and physiological measurements have revealed that modern football is highly energetically demanding, and the ability to perform repeated high-intensity work is of importance for the players. Furthermore, the most successful teams perform more high-intensity activities during a game when in possession of the ball. Hence, footballers need a high fitness level to cope with the physical demands of the game. Studies on football players have shown that 8 to 12 wk of aerobic high-intensity running training (> 85% HR(max)) leads to VO2(max) enhancement (5% to 11%), increased running economy (3% to 7%), and lower blood lactate accumulation during submaximal exercise, as well as improvements in the yo-yo intermittent recovery (YYIR) test performance (13%). Similar adaptations are observed when performing aerobic high-intensity training with small-sided games. Speed-endurance training has a positive effect on football-specific endurance, as shown by the marked improvements in the YYIR test (22% to 28%) and the ability to perform repeated sprints (approximately 2%). In conclusion, both aerobic and speed-endurance training can be used during the season to improve high-intensity intermittent exercise performance. The type and amount of training should be game related and specific to the technical, tactical, and physical demands imposed on each player.

  2. High-intensity and resistance training and elite young athletes.

    PubMed

    Ratel, Sébastien

    2011-01-01

    Although in the past resistance and high-intensity exercise training among young children was the subject of numerous controversies, it is now well-documented that this training mode is a safe and effective means of developing maximal strength, maximal power output and athletic performance in youth, provided that exercises are performed with appropriate supervision and precautions. Muscular strength and power output values measured from vertical jump and Wingate anaerobic tests are higher in elite than in non-elite young athletes and normal children, and the specific training effects on maximal power output normalised for body size are clearly more distinct before puberty. At present, there is no scientific evidence to support the view that high-intensity and/or resistance training might hinder growth and maturation in young children. Pre-pubertal growth is not adversely affected by sport at a competitive level and anthropometric factors are of importance for choice of sport in children. However, coaches, teachers and parents should be aware that unsupervised high-intensity and resistance training programmes involving maximal loads or too frequently repeated resistance exercises increase the risk of injury. Resistance training alone is an effective additional means of developing athletic performance throughout planned youth sports training programmes. Strategies for enhancing the effectiveness and safety of youth resistance and high-intensity exercise training are discussed in this chapter.

  3. Precast concrete sandwich panels subjected to impact loading

    NASA Astrophysics Data System (ADS)

    Runge, Matthew W.

    Precast concrete sandwich panels are a relatively new product in the construction industry. The design of these panels incorporates properties that allow for great resilience against temperature fluctuation as well as the very rapid and precise construction of facilities. The concrete sandwich panels investigated in this study represent the second generation of an ongoing research and development project. This second generation of panels have been engineered to construct midsized commercial buildings up to three stories in height as well as residential dwellings. The panels consist of a double-tee structural wythe, a foam core and a fascia wythe, joined by shear connectors. Structures constructed from these panels may be subjected to extreme loading including the effects of seismic and blast loading in addition to wind. The aim of this work was to investigate the behaviour of this particular sandwich panel when subjected to structural impact events. The experimental program consisted of fourteen concrete sandwich panels, five of which were considered full-sized specimens (2700 mm X 1200mm X 270 mm) and nine half-sized specimens (2700mm X 600mm X 270 mm) The panels were subjected to impact loads from a pendulum impact hammer where the total energy applied to the panels was varied by changing the mass of the hammer. The applied loads, displacements, accelerations, and strains at the mid-span of the panel as well as the reaction point forces were monitored during the impact. The behaviour of the panels was determined primarily from the experimental results. The applied loads at low energy levels that caused little to no residual deflection as well as the applied loads at high energy levels that represent catastrophic events and thus caused immediate failure were determined from an impact on the structural and the fascia wythes. Applied loads at intermediate energy levels representing extreme events were also used to determine whether or not the panels could withstand

  4. Closing of cracks under impact loading

    SciTech Connect

    Finkel', V.M.; Fomin, I.M.; Shegai, V.V.

    1985-12-01

    The healing of cracks has been studied in crystalline materials such as diamond, sodium chloride, tungsten, molybdenum and quartz, and the possibility has also been studied of restoring material continuity to sodium chloride and lithium fluoride single crystals under conditions of relatively prolonged compression over a time range of from one to tens of seconds. Potential restoration of interatomic bonds between surfaces of failed material (reanimation) precedes collapse of a crack as a process of approach of its edges before mechanical contact. The goal of this work is to study crack closing with short-term impact.

  5. Impact of discharge data uncertainty on nutrient load uncertainty

    NASA Astrophysics Data System (ADS)

    Westerberg, Ida; Gustavsson, Hanna; Sonesten, Lars

    2016-04-01

    Uncertainty in the rating-curve model of the stage-discharge relationship leads to uncertainty in discharge time series. These uncertainties in turn affect many other analyses based on discharge data, such as nutrient load estimations. It is important to understand how large the impact of discharge data uncertainty is on such analyses, since they are often used as the basis to take important environmental management decisions. In the Baltic Sea basin, nutrient load estimates from river mouths are a central information basis for managing and reducing eutrophication in the Baltic Sea. In this study we investigated rating curve uncertainty and its propagation to discharge data uncertainty and thereafter to uncertainty in the load of phosphorous and nitrogen for twelve Swedish river mouths. We estimated rating curve uncertainty using the Voting Point method, which accounts for random and epistemic errors in the stage-discharge relation and allows drawing multiple rating-curve realisations consistent with the total uncertainty. We sampled 40,000 rating curves, and for each sampled curve we calculated a discharge time series from 15-minute water level data for the period 2005-2014. Each discharge time series was then aggregated to daily scale and used to calculate the load of phosphorous and nitrogen from linearly interpolated monthly water samples, following the currently used methodology for load estimation. Finally the yearly load estimates were calculated and we thus obtained distributions with 40,000 load realisations per year - one for each rating curve. We analysed how the rating curve uncertainty propagated to the discharge time series at different temporal resolutions, and its impact on the yearly load estimates. Two shorter periods of daily water quality sampling around the spring flood peak allowed a comparison of load uncertainty magnitudes resulting from discharge data with those resulting from the monthly water quality sampling.

  6. Characteristic evaluation of CFRP composites under falling weight impact loading

    NASA Astrophysics Data System (ADS)

    Im, K. H.; Park, N. S.; Hsu, D. K.; Kim, S. K.; Park, J. W.; Yang, I. Y.

    2002-05-01

    This paper describes a method for a falling weight impact test to estimate the impact energy absorbing characteristics and impact strength of carbon-fiber reinforced plastics (CFRP) laminate plates based on considerations of stress wave propagation theory, which were converted to measurements of load and displacement verses time. The delamination area of impacted specimens for the different ply orientations was measured with an ultrasonic C-scanner to determine the correlation between impact energy and delamination area. The energy absorbed by a quasi-isotropic specimen having four interfaces was higher than that of orthotropic laminates with two interfaces. The more interfaces, the greater the energy absorbed. The absorbed energy of a hybrid specimen containing a CFRP layer was higher than that of normal specimens. Also, a falling weight impact tester was built to evaluate the characteristics and impact strength of CFRPs.

  7. Rapidly pulsed, high intensity, incoherent light source

    NASA Technical Reports Server (NTRS)

    Evans, J. C., Jr.; Brandhorst, H. W., Jr. (Inventor)

    1974-01-01

    A rapid pulsing, high intensity, incoherent light is produced by selectively energizing a plurality of discharge lamps with a triggering circuit. Each lamp is connected to a capacitor, and a power supply is electrically connected to all but one of the capacitors. This last named capacitor is electrically connected to a discharge lamp which is connected to the triggering circuit.

  8. High-intensity source of extreme ultraviolet

    NASA Technical Reports Server (NTRS)

    Paresce, E.; Kumar, S.; Bowyer, S.

    1972-01-01

    High intensity ultraviolet radiation source was developed which is suitable for emission below 500 A. Source, useful for 100 to 1000 A range, is simple and inexpensive to construct, easy to operate, and very stable. Because of sufficiently intense output spectrum, source can be used with monochromator at wavelengths as low as 160 A.

  9. The NASA High Intensity Radiated Fields Laboratory

    NASA Technical Reports Server (NTRS)

    Williams, Reuben A.

    1997-01-01

    High Intensity Radiated Fields (HIRF) are the result of a multitude of intentional and nonintentional electromagnetic sources that currently exists in the world. Many of today's digital systems are susceptible to electronic upset if subjected to certain electromagnetic environments (EME). Modern aerospace designers and manufacturers increasingly rely on sophisticated digital electronic systems to provide critical flight control in both military, commercial, and general aviation aircraft. In an effort to understand and emulate the undesired environment that high energy RF provides modern electronics, the Electromagnetics Research Branch (ERB) of the Flight Electronics and Technology Division (FETD) conducts research on RF and microwave measurement methods related to the understanding of HIRF. In the High Intensity Radiated Fields Laboratory, the effects of high energy radiating electromagnetic fields on avionics and electronic systems are tested and studied.

  10. Positron microanalysis with high intensity beams

    SciTech Connect

    Hulett, L.D. Jr.; Donohue, D.L.

    1990-01-01

    One of the more common applications for a high intensity slow positron facility will be microanalysis of solid materials. In the first section of this paper some examples are given of procedures that can be developed. Since most of the attendees of this workshop are experts in positron spectroscopy, comprehensive descriptions will be omitted. With the exception of positron emission microscopy, most of the procedures will be based on those already in common use with broad beams. The utility of the methods have all been demonstrated, but material scientists use very few of them because positron microbeams are not generally available. A high intensity positron facility will make microbeams easier to obtain and partially alleviate this situation. All microanalysis techniques listed below will have a common requirement, which is the ability to locate the microscopic detail or area of interest and to focus the positron beam exclusively on it. The last section of this paper is a suggestion of how a high intensity positron facility might be designed so as to have this capability built in. The method will involve locating the specimen by scanning it with the microbeam of positrons and inducing a secondary electron image that will immediately reveal whether or not the positron beam is striking the proper portion of the specimen. This scanning positron microscope' will be a somewhat prosaic analog of the conventional SEM. It will, however, be an indispensable utility that will enhance the practicality of positron microanalysis techniques. 6 refs., 1 fig.

  11. Damage assessment in CFRP laminates exposed to impact fatigue loading

    NASA Astrophysics Data System (ADS)

    Tsigkourakos, George; Silberschmidt, Vadim V.; Ashcroft, I. A.

    2011-07-01

    Demand for advanced engineering composites in the aerospace industry is increasing continuously. Lately, carbon fibre reinforced polymers (CFRPs) became one of the most important structural materials in the industry due to a combination of characteristics such as: excellent stiffness, high strength-to-weight ratio, and ease of manufacture according to application. In service, aerospace composite components and structures are exposed to various transient loads, some of which can propagate in them as cyclic impacts. A typical example is an effect of the wind gusts during flight. This type of loading is known as impact fatigue (IF); it is a repetition of low-energy impacts. Such loads can cause various types of damage in composites: fibre breaking, transverse matrix cracking, de-bonding between fibres and matrix and delamination resulting in reduction of residual stiffness and loss of functionality. Furthermore, this damage is often sub-surface, which reinforces the need for more regular inspection. The effects of IF are of major importance due its detrimental effect on the structural integrity of components that can be generated after relatively few impacts at low force levels compared to those in a standard fatigue regime. This study utilises an innovative testing system with the capability of subjecting specimens to a series of repetitive impacts. The primary subject of this paper is to assess the damaging effect of IF on the behaviour of drilled CFRP specimens, exposed to such loading. A detailed damage analysis is implemented utilising an X-ray micro computed tomography system. The main findings suggested that at early stages of life damage is governed by o degree splits along the length of the specimens resulting in a 20% reduction of stiffness. The final failure damage scenario indicated that transverse crasks in the 90 degree plies are the main reason for complete delamination which can be translated to a 50% stiffness reduction.

  12. Survey of proposed high intensity accelerators and their applications

    SciTech Connect

    Schriber, S.O.

    1994-09-01

    Many interesting applications are being considered for high intensity accelerators. Implications of the technology developments that are enhancing these opportunities, or making them possible, will be covered in context of the applications. Applications include those for research (in areas such as material science, biological sciences, nuclear and high energy physics), accelerator-driven transmutation technologies, defense, and medicine. Specific examples will be used to demonstrate the impact that technology development can have and how transfer of this technology to industry can have an impact in the consumer and commercial arenas. Technology Development in rf power, controls, beam optics, rf structures, magnets, injectors, and beam halos will be considered.

  13. Load and wear experiments on the impact hammer of a vertical shaft impact crusher

    NASA Astrophysics Data System (ADS)

    Yang, J. H.; Fang, H. Y.; Luo, M.

    2015-12-01

    Impact hammers are important components of impact crushers, and are often shortlived due to the high-impact nature of their use. Wear-resistant alloys are welded to the surface of impact hammers to prolong their service life. In this paper, a simulation model of the rotor and impact hammers in impact crushers was designed to utilize the Discrete Element Method (DEM). The wear-resistant alloy on each impact hammer was divided into twenty-two action regions. The load distribution on each alloy block is affected by the structural and manufacturing parameters of the impact crusher. The wear distribution of the impact hammer was measured by shape morphology according to relative impact crushers. The results demonstrated that the real measurements of wear distribution on the impact hammer were similar to simulated load distribution measurements on the same surface. The study of load distribution of impact hammers by DEM established a theoretical foundation on which to base the optimal design of impact crushers.

  14. Impact of Applied Loads on Guided Wave Structural Health Monitoring

    NASA Astrophysics Data System (ADS)

    Michaels, Jennifer E.; Lee, Sang Jun; Michaels, Thomas E.

    2011-06-01

    Guided wave structural health monitoring is a challenging problem, in part because of the complexity of signals received in a real structure containing geometrical features and boundaries. Signals scattered from damage can be one or two orders of magnitude smaller in amplitude than the direct arrival. Detection of these small, scattered signals is often accomplished by comparing signals of interest to one or more baseline signals recorded from the undamaged structure. Previous work by many researchers has shown that homogeneous temperature changes as small as a few degrees Celsius can mask damage unless compensation is made. Here we consider the impact of applied loads on complex guided wave signals because such loading effects may be unavoidable in the in situ environment. Experiments were performed and are described where data from a spatially distributed array of piezoelectric sensors are recorded as a function of applied uniaxial load before and after introduction of simulated damage via an attached mass. Load-dependent signal changes in both short and long time regimes are considered, and their impact on structural health monitoring is discussed.

  15. Analysis of the Behavior of Sedimentary Rocks Under Impact Loading

    NASA Astrophysics Data System (ADS)

    Millon, Oliver; Ruiz-Ripoll, Maria Luisa; Hoerth, Tobias

    2016-11-01

    In multiple engineering fields such as rock drilling or building constructions or extreme events like earthquakes or impacts, the dynamic properties of rock play an important role. A way to model these events and define measures to minimize the damage derived from these events is created by means of numerical analysis. Hence, the knowledge of the dynamic material behavior is essential for studying the effects of such a loading scenario. Solid geological materials, from the family of the sedimentary rocks, have been analyzed under quasi-static loads. However, there is a lack of knowledge when high strain rate loadings are involved. Within this context, the paper focuses on the experimental characterization of two sedimentary rocks, sandstone and limestone, under impact loading using the Hopkinson-Bar spallation and compression tests. The analysis encompasses the determination of the tensile and compressive properties as well as the comparison between the quasi-static and dynamic behavior (dynamic increase factors). The paper fills the gap of information existing about dynamic behavior of sedimentary rocks under strain rates between 100 and 5.2 × 102 s-1. Furthermore, the fragmentation under different strain rates is investigated and conclusions with respect to energy absorption capacity are drawn.

  16. Alpine Skiing as Winter-Time High-Intensity Training.

    PubMed

    Stöggl, Thomas Leonhard; Schwarzl, Christoph; Müller, Edith E; Nagasaki, Masaru; Stöggl, Julia; Schönfelder, Martin; Niebauer, Josef

    2017-09-01

    To counteract the winter activity deficit, we set out to analyze cardiorespiratory and metabolic responses of two high-intensity training (HIT) protocols during alpine skiing (AS), cross-country skiing (XCS), and indoor cycling (IC) and the effects of sex, age, and fitness level in this comparison. Nineteen healthy subjects (two age and fitness groups, both sexes) performed AS, XCS, and IC with measurements of oxygen uptake (V˙O2), energy expenditure (EE), HR, lactate, blood glucose and rate of perceived exertion, determined during 4 min of continuous HIT (HITc: 90% HRmax for XCS and IC or short turn skiing during AS) or 10-min intermittent HIT [HITint: 5 × 1 min high intensity (>90% HRmax or short turn skiing), 1 min active recovery]. During all three exercise modes and irrespective of HIT protocols, sex, age, and fitness, participants were able to reach exercise intensities >90% HRmax and >84% V˙O2max. In all exercise modes 10-min of HITint with a 10-min postexercise O2 consumption phase resulted in greater mean EE per minute compared to 4-min HITc with 10 min postexercise O2 consumption. When applying the same HIT loading and recovery pattern to all three exercise modes, EE during approximately 1:15 h of AS was equivalent to about 1:00 h of either XCS or IC. Across all exercise modes and HIT protocols, high cardiorespiratory and metabolic responses were achieved regardless of age, sex, or fitness. EE during AS can be maximized by choosing the skiing mode "short turn skiing" in combination with an HITint to prolong the duration of continuous high-intensity loading during each descent. Therefore, all exercise modes and both HIT protocols are applicable and feasible in a broad spectrum of healthy subjects.

  17. Impact of high biomass loading on ionic liquid pretreatment

    PubMed Central

    2013-01-01

    Background Ionic liquid (IL) pretreatment has shown great potential as a novel pretreatment technology with high sugar yields. To improve process economics of pretreatment, higher biomass loading is desirable. The goal of this work is to establish, the impact of high biomass loading of switchgrass on IL pretreatment in terms of viscosity, cellulose crystallinity, chemical composition, saccharification kinetics, and sugar yield. Results The pretreated switchgrass/IL slurries show frequency dependent shear thinning behavior. The switchgrass/IL slurries show a crossover from viscous behavior at 3 wt% to elastic behavior at 10 wt%. The relative glucan content of the recovered solid samples is observed to decrease with increasing levels of lignin and hemicelluloses with increased biomass loading. The IL pretreatment led to a transformation of cellulose crystalline structure from I to II for 3, 10, 20 and 30 wt% samples, while a mostly amorphous structure was found for 40 and 50 wt% samples. Conclusions IL pretreatment effectively reduced the biomass recalcitrance at loadings as high as 50 wt%. Increased shear viscosity and a transition from ‘fluid’ like to ‘solid’ like behavior was observed with increased biomass loading. At high biomass loadings shear stress produced shear thinning behavior and a reduction in viscosity by two orders of magnitude, thereby reducing the complex viscosity to values similar to lower loadings. The rheological properties and sugar yields indicate that 10 to 50 wt% may be a reasonable and desirable target for IL pretreatment under certain operating conditions. PMID:23578017

  18. The strength of laminated composite materials under repeated impact loading

    NASA Technical Reports Server (NTRS)

    Rotem, Assa

    1988-01-01

    When low velocity and energy impact is exerted on a laminated composite material, in a perpendicular direction to the plane of the laminate, invisible damage may develop. It is shown analytically and experimentally that the invisible damage occurs during the first stage of contact between the impactor and the laminate and is a result of the contact stresses. However, the residual flexural strength changes only slightly, because it depends mainly on the outer layers, and these remain undamaged. Repeated impact intensifies the damage inside the laminate and causes larger bending under equivalent impact load. Finally, when the damage is most severe, even though it is still invisible, the laminate fails because of bending on the tension side. If the repeated impact is halted before final fracture occurs the residual strength and modulus would decrease by a certain amount.

  19. The strength of laminated composite materials under repeated impact loading

    NASA Technical Reports Server (NTRS)

    Rotem, Assa

    1988-01-01

    When low velocity and energy impact is exerted on a laminated composite material, in a perpendicular direction to the plane of the laminate, invisible damage may develop. It is shown analytically and experimentally that the invisible damage occurs during the first stage of contact between the impactor and the laminate and is a result of the contact stresses. However, the residual flexural strength changes only slightly, because it depends mainly on the outer layers, and these remain undamaged. Repeated impact intensifies the damage inside the laminate and causes larger bending under equivalent impact load. Finally, when the damage is most severe, even though it is still invisible, the laminate fails because of bending on the tension side. If the repeated impact is halted before final fracture occurs the residual strength and modulus would decrease by a certain amount.

  20. DEFORMATION CHARACTERISTICS OF CRUSHED-STONE LAYER UNDER CYCLIC IMPACT LOADING FROM MICRO-MECHANICAL VIEW

    NASA Astrophysics Data System (ADS)

    Kono, Akiko; Matsushima, Takashi

    'Hanging sleepers', which have gaps between sleepers and ballast layer are often found in the neighborhood of rail joints or rugged surface rails. This suggests that differential settlement of the ballast layer is due to impact loading generated by the contact between running wheel and rugged surface rail. Then cyclic loading tests were performed on crushed-stone layer with two loading patterns, the one is a cyclic impact loading and the other one is cyclic 'standard' loading controlled at 1/10 loading velocity of the impact loading. It was shown that the crashed-stone layer deforms with volumetric expansion during every off-loading processes under the cyclic impact loading. This phenomena prevents crushed stone layer from forming stable grain columns, then the residual settlement under the cyclic impact loading is larger than that under the cyclic 'standard' loading. A simple mass-spring model simulates that two masses move in the opposite direction with increased frequency of harmonic excitation.

  1. Numerical and Experimental Studies on Impact Loaded Concrete Structures

    SciTech Connect

    Saarenheimo, Arja; Hakola, Ilkka; Karna, Tuomo; Hyvarinen, Juhani

    2006-07-01

    An experimental set-up has been constructed for medium scale impact tests. The main objective of this effort is to provide data for the calibration and verification of numerical models of a loading scenario where an aircraft impacts against a nuclear power plant. One goal is to develop and take in use numerical methods for predicting response of reinforced concrete structures to impacts of deformable projectiles that may contain combustible liquid ('fuel'). Loading, structural behaviour, like collapsing mechanism and the damage grade, will be predicted by simple analytical methods and using non-linear FE-method. In the so-called Riera method the behavior of the missile material is assumed to be rigid plastic or rigid visco-plastic. Using elastic plastic and elastic visco-plastic material models calculations are carried out by ABAQUS/Explicit finite element code, assuming axisymmetric deformation mode for the missile. With both methods, typically, the impact force time history, the velocity of the missile rear end and the missile shortening during the impact were recorded for comparisons. (authors)

  2. Advanced modeling of high intensity accelerators

    SciTech Connect

    Ryne, R.D.; Habib, S.; Wangler, T.P.

    1998-11-01

    This is the final report of a three-year, Laboratory Directed Research and Development (LDRD) project at the Los Alamos National Laboratory (LANL). The goals of this project were three-fold: (1) to develop a new capability, based on high performance (parallel) computers, to perform large scale simulations of high intensity accelerators; (2) to apply this capability to modeling high intensity accelerators under design at LANL; and (3) to use this new capability to improve the understanding of the physics of intense charge particle beams, especially in regard to the issue of beam halo formation. All of these goals were met. In particular, the authors introduced split-operator methods as a powerful and efficient means to simulate intense beams in the presence of rapidly varying accelerating and focusing fields. They then applied these methods to develop scaleable, parallel beam dynamics codes for modeling intense beams in linacs, and in the process they implemented a new three-dimensional space charge algorithm. They also used the codes to study a number of beam dynamics issues related to the Accelerator Production of Tritium (APT) project, and in the process performed the largest simulations to date for any accelerator design project. Finally, they used the new modeling capability to provide direction and validation to beam physics studies, helping to identify beam mismatch as a major source of halo formation in high intensity accelerators. This LDRD project ultimately benefited not only LANL but also the US accelerator community since, by promoting expertise in high performance computing and advancing the state-of-the-art in accelerator simulation, its accomplishments helped lead to approval of a new DOE Grand Challenge in Computational Accelerator Physics.

  3. High intensity, pulsed thermal neutron source

    DOEpatents

    Carpenter, J.M.

    1973-12-11

    This invention relates to a high intensity, pulsed thermal neutron source comprising a neutron-producing source which emits pulses of fast neutrons, a moderator block adjacent to the last neutron source, a reflector block which encases the fast neutron source and the moderator block and has a thermal neutron exit port extending therethrough from the moderator block, and a neutron energy- dependent decoupling reflector liner covering the interior surfaces of the thermal neutron exit port and surrounding all surfaces of the moderator block except the surface viewed by the thermal neutron exit port. (Official Gazette)

  4. Plating Processes Utilizing High Intensity Acoustic Beams

    NASA Technical Reports Server (NTRS)

    Oeftering, Richard C. (Inventor); Denofrio, Charles (Inventor)

    2002-01-01

    A system and a method for selective plating processes are disclosed which use directed beams of high intensity acoustic waves to create non-linear effects that alter and improve the plating process. The directed beams are focused on the surface of an object, which in one embodiment is immersed in a plating solution, and in another embodiment is suspended above a plating solution. The plating processes provide precise control of the thickness of the layers of the plating, while at the same time, in at least some incidents, eliminates the need for masking.

  5. Evidence based exercise - clinical benefits of high intensity interval training.

    PubMed

    Shiraev, Tim; Barclay, Gabriella

    2012-12-01

    Aerobic exercise has a marked impact on cardiovascular disease risk. Benefits include improved serum lipid profiles, blood pressure and inflammatory markers as well as reduced risk of stroke, acute coronary syndrome and overall cardiovascular mortality. Most exercise programs prescribed for fat reduction involve continuous, moderate aerobic exercise, as per Australian Heart Foundation clinical guidelines. This article describes the benefits of exercise for patients with cardiovascular and metabolic disease and details the numerous benefits of high intensity interval training (HIIT) in particular. Aerobic exercise has numerous benefits for high-risk populations and such benefits, especially weight loss, are amplified with HIIT. High intensity interval training involves repeatedly exercising at a high intensity for 30 seconds to several minutes, separated by 1-5 minutes of recovery (either no or low intensity exercise). HIT is associated with increased patient compliance and improved cardiovascular and metabolic outcomes and is suitable for implementation in both healthy and 'at risk' populations. Importantly, as some types of exercise are contraindicated in certain patient populations and HIIT is a complex concept for those unfamiliar to exercise, some patients may require specific assessment or instruction before commencing a HIIT program.

  6. Mechanical Model for Dynamic Behavior of Concrete Under Impact Loading

    NASA Astrophysics Data System (ADS)

    Sun, Yuanxiang

    Concrete is a geo-material which is used substantively in the civil building and military safeguard. One coupled model of damage and plasticity to describe the complex behavior of concrete subjected to impact loading is proposed in this research work. The concrete is assumed as homogeneous continuum with pre-existing micro-cracks and micro-voids. Damage to concrete is caused due to micro-crack nucleation, growth and coalescence, and defined as the probability of fracture at a given crack density. It induces a decrease of strength and stiffness of concrete. Compaction of concrete is physically a collapse of the material voids. It produces the plastic strain in the concrete and, at the same time, an increase of the bulk modulus. In terms of crack growth model, micro-cracks are activated, and begin to propagate gradually. When crack density reaches a critical value, concrete takes place the smashing destroy. The model parameters for mortar are determined using plate impact experiment with uni-axial strain state. Comparison with the test results shows that the proposed model can give consistent prediction of the impact behavior of concrete. The proposed model may be used to design and analysis of concrete structures under impact and shock loading. This work is supported by State Key Laboratory of Explosion science and Technology, Beijing Institute of Technology (YBKT14-02).

  7. High intensity discharge device containing oxytrihalides

    DOEpatents

    Lapatovich, Walter P.; Keeffe, William M.; Liebermann, Richard W.; Maya, Jakob

    1987-01-01

    A fill composition for a high intensity discharge device including mercury, niobium oxytrihalide, and a molecular stabilization agent is provided. The molar ratio of niobium oxytrihalide to the molecular stabilization agent in the fill is in the range of from about 5:1 to about 7.5:1. Niobium oxytrihalide is present in the fill in sufficient amount to produce, by dissociation in the discharge, atomic niobium, niobium oxide, NbO, and niobium dioxide, NbO.sub.2, with the molar ratio of niobium-containing vapor species to mercury in the fill being in the range of from about 0.01:1 to about 0.50:1; and mercury pressure of about 1 to about 50 atmospheres at lamp operating temperature. There is also provided a high intensity discharge device comprising a sealed light-transmissive arc tube; the arc tube including the above-described fill; and an energizing means for producing an electric discharge within the arc tube.

  8. High intensity discharge device containing oxytrihalides

    DOEpatents

    Lapatovich, W.P.; Keeffe, W.M.; Liebermann, R.W.; Maya, J.

    1987-06-09

    A fill composition for a high intensity discharge device including mercury, niobium oxytrihalide, and a molecular stabilization agent is provided. The molar ratio of niobium oxytrihalide to the molecular stabilization agent in the fill is in the range of from about 5:1 to about 7.5:1. Niobium oxytrihalide is present in the fill in sufficient amount to produce, by dissociation in the discharge, atomic niobium, niobium oxide, NbO, and niobium dioxide, NbO[sub 2], with the molar ratio of niobium-containing vapor species to mercury in the fill being in the range of from about 0.01:1 to about 0.50:1; and mercury pressure of about 1 to about 50 atmospheres at lamp operating temperature. There is also provided a high intensity discharge device comprising a sealed light-transmissive arc tube; the arc tube including the above-described fill; and an energizing means for producing an electric discharge within the arc tube. 7 figs.

  9. Radiation reaction in high-intensity fields

    NASA Astrophysics Data System (ADS)

    Seto, Keita

    2015-10-01

    Since the development of a radiating electron model by Dirac in 1938 [P. A. M. Dirac, Proc. R. Soc. Lond. A 167, 148 (1938)], many authors have tried to reformulate this model of the so-called "radiation reaction". Recently, this effect has become important in ultra-intense laser-electron (plasma) interactions. In our recent research, we found a way of stabilizing the radiation reaction by quantum electrodynamics (QED) vacuum fluctuation [K Seto et al., Prog. Theor. Exp. Phys. 2014, 043A01 (2014); K. Seto, Prog. Theor. Exp. Phys. 2015, 023A01 (2015)]. On the other hand, the modification of the radiated field by highly intense incoming laser fields should be taken into account when the laser intensity is higher than 10^{22} W/cm2, which could be achieved by next-generation ultra-short-pulse 10 PW lasers, like the ones under construction for the ELI-NP facility. In this paper, I propose a running charge-mass method for the description of the QED-based synchrotron radiation by high-intensity external fields with stabilization by the QED vacuum fluctuation as an extension from the model by Dirac.

  10. The impact of cognitive load on reward evaluation.

    PubMed

    Krigolson, Olave E; Hassall, Cameron D; Satel, Jason; Klein, Raymond M

    2015-11-19

    The neural systems that afford our ability to evaluate rewards and punishments are impacted by a variety of external factors. Here, we demonstrate that increased cognitive load reduces the functional efficacy of a reward processing system within the human medial-frontal cortex. In our paradigm, two groups of participants used performance feedback to estimate the exact duration of one second while electroencephalographic (EEG) data was recorded. Prior to performing the time estimation task, both groups were instructed to keep their eyes still and avoid blinking in line with well established EEG protocol. However, during performance of the time-estimation task, one of the two groups was provided with trial-to-trial-feedback about their performance on the time-estimation task and their eye movements to induce a higher level of cognitive load relative to participants in the other group who were solely provided with feedback about the accuracy of their temporal estimates. In line with previous work, we found that the higher level of cognitive load reduced the amplitude of the feedback-related negativity, a component of the human event-related brain potential associated with reward evaluation within the medial-frontal cortex. Importantly, our results provide further support that increased cognitive load reduces the functional efficacy of a neural system associated with reward processing.

  11. Method for Investigation of Frictional Properties at Impact Loading

    NASA Astrophysics Data System (ADS)

    Sundin, K. G.; Åhrström, B. O.

    1999-05-01

    In the assessment of lubricant performance and also in various other contact applications it is of importance to know the frictional qualities of a surface. Under quasi-static conditions, normal and frictional forces are measured using force transducers but the task is more difficult when loads are transient. The experimental method presented in this paper is based on the analysis of propagating waves in a beam, due to an impact on the end surface. The impact is oblique and therefore a transverse as well as a normal force is generated. The normal force history is measured from the axial non-dispersive wave using strain gauges. Transverse force and bending moment both generate dispersive flexural waves. From the FFT of two transverse acceleration histories, the frictional force at the end of the rod is evaluated using beam theory. The relation between normal and frictional force histories displays the frictional properties at the impact. Preliminary results are presented.

  12. Damage in woven CFRP laminates under impact loading

    NASA Astrophysics Data System (ADS)

    Ullah, H.; Harland, A. R.; Silberschmidt, V. V.

    2012-08-01

    Carbon fibre-reinforced polymer (CFRP) composites used in sports products can be exposed to different in-service conditions such as large dynamic bending deformations caused by impact loading. Composite materials subjected to such loads demonstrate various damage modes such as matrix cracking, delamination and, ultimately, fabric fracture. Damage evolution affects both in-service properties and performance of CFRP that can deteriorate with time. These failure modes need adequate means of analysis and investigation, the major approaches being experimental characterisation and numerical simulations. This research deals with a deformation behaviour and damage in composite laminates due to dynamic bending. Experimental tests are carried out to characterise the behaviour of a woven CFRP material under large-deflection dynamic bending in impact tests carried out to obtain the force-time and absorbed energy profiles for CFRP laminates. Damage in the impacted laminates is analysed using optical microscopy. Numerical simulations are performed to study the deformation behaviour and damage in CFRP for cases of large-deflection bending based on three-dimensional finite-element models implemented in the commercial code Abaqus/Explicit. Multiple layers of bilinear cohesive-zone elements are employed to model the initiation and progression of inter-ply delamination observed in the microscopy studies. The obtained results of simulations show good agreement with experimental data.

  13. The Impact of 3 Different-Length Between-Matches Microcycles on Training Loads in Professional Rugby League Players.

    PubMed

    Moreira, Alexandre; Kempton, Tom; Aoki, Marcelo Saldanha; Sirotic, Anita C; Coutts, Aaron J

    2015-09-01

    To examine the impact of varying between-matches microcycles on training characteristics (ie, intensity, duration, and load) in professional rugby league players and to report on match load related to these between-matches microcycles. Training-load data were collected during a 26-wk competition period of an entire season. Training load was measured using the session rating of perceived exertion (session-RPE) method for every training session and match from 44 professional rugby league players from the same National Rugby League team. Using the category-ratio 10 RPE scale, the training intensity was divided into 3 zones (low <4 AU, moderate ≥ 4-≤ 7 AU, and high >7 AU). Three different-length between-matches recovery microcycles were used for analysis: 5-6 d, 7-8 d, and 9-10 d. A total of 3848 individual sessions were recorded. During the shorter-length between-matches microcycles (5-6 d), significantly lower training load was observed. No significant differences for subsequent match load or intensity were identified between the various match recovery periods. Overall, 16% of the training sessions were completed at the low-intensity zone, 61% at the moderate-intensity zone, and 23% at the high-intensity zone. The findings demonstrate that rugby league players undertake higher training load as the length of between-matches microcycles is increased. The majority of in-season training of professional rugby league players was at moderate intensity, and a polarized approach to training that has been reported in elite endurance athletes does not occur in professional rugby league.

  14. A technique for measuring dynamic friction coefficient under impact loading.

    PubMed

    Lin, Y L; Qin, J G; Chen, R; Zhao, P D; Lu, F Y

    2014-09-01

    We develop a novel setup based on the split Hopkinson pressure bar technique to test the dynamic friction coefficient under impact loading. In the setup, the major improvement is that the end of the incident bar near the specimen is wedge-shaped, which results in a combined compressive and shear loading applied to the specimen. In fact, the shear loading is caused by the interfacial friction between specimen and bars. Therefore, when the two loading force histories are measured, the friction coefficient histories can be calculated without any assumptions and theoretical derivations. The geometry of the friction pairs is simple, and can be either cuboid or cylindrical. Regarding the measurements, two quartz transducers are used to directly record the force histories, and an optical apparatus is designed to test the interfacial slip movement. By using the setup, the dynamic friction coefficient of PTFE/aluminum 7075 friction pairs was tested. The time resolved dynamic friction coefficient and slip movement histories were achieved. The results show that the friction coefficient changes during the loading process, the average data of the relatively stable flat plateau section of the friction coefficient curves is 0.137, the maximum normal pressure is 52 MPa, the maximum relative slip velocity is 1.5 m/s, and the acceleration is 8400 m(2)/s. Furthermore, the friction test was simulated using an explicit FEM code LS-DYNA. The simulation results showed that the constant pressure and slip velocity can both be obtained with a wide flat plateau incident pulse. For some special friction pairs, normal pressure up to a few hundred MPa, interfacial slip velocities up to 10 m/s, and slip movement up to centimeter-level can be expected.

  15. A technique for measuring dynamic friction coefficient under impact loading

    NASA Astrophysics Data System (ADS)

    Lin, Y. L.; Qin, J. G.; Chen, R.; Zhao, P. D.; Lu, F. Y.

    2014-09-01

    We develop a novel setup based on the split Hopkinson pressure bar technique to test the dynamic friction coefficient under impact loading. In the setup, the major improvement is that the end of the incident bar near the specimen is wedge-shaped, which results in a combined compressive and shear loading applied to the specimen. In fact, the shear loading is caused by the interfacial friction between specimen and bars. Therefore, when the two loading force histories are measured, the friction coefficient histories can be calculated without any assumptions and theoretical derivations. The geometry of the friction pairs is simple, and can be either cuboid or cylindrical. Regarding the measurements, two quartz transducers are used to directly record the force histories, and an optical apparatus is designed to test the interfacial slip movement. By using the setup, the dynamic friction coefficient of PTFE/aluminum 7075 friction pairs was tested. The time resolved dynamic friction coefficient and slip movement histories were achieved. The results show that the friction coefficient changes during the loading process, the average data of the relatively stable flat plateau section of the friction coefficient curves is 0.137, the maximum normal pressure is 52 MPa, the maximum relative slip velocity is 1.5 m/s, and the acceleration is 8400 m2/s. Furthermore, the friction test was simulated using an explicit FEM code LS-DYNA. The simulation results showed that the constant pressure and slip velocity can both be obtained with a wide flat plateau incident pulse. For some special friction pairs, normal pressure up to a few hundred MPa, interfacial slip velocities up to 10 m/s, and slip movement up to centimeter-level can be expected.

  16. Delaminations in composite plates under transverse impact loads - Experimental results

    NASA Technical Reports Server (NTRS)

    Finn, Scott R.; He, Ye-Fei; Springer, George S.

    1993-01-01

    Tests were performed measuring the locations and geometries of delaminations in Fiberite T300/976 graphite/epoxy, Fiberite IM7/977-2 graphite-toughened epoxy, and ICI APC-2 graphite/PEEK plates subjected to transverse impact loads. The data provide specific information on the effects of impactor velocity, impactor mass, material, thickness of back ply group, difference in fiber orientation between adjacent ply groups, plate thickness, and impactor nose radius. The data were compared to the results of the Finn-Springer model. The model was found to describe the data with reasonable accuracy.

  17. Applications of High Intensity Proton Accelerators

    NASA Astrophysics Data System (ADS)

    Raja, Rajendran; Mishra, Shekhar

    2010-06-01

    Superconducting radiofrequency linac development at Fermilab / S. D. Holmes -- Rare muon decay experiments / Y. Kuno -- Rare kaon decays / D. Bryman -- Muon collider / R. B. Palmer -- Neutrino factories / S. Geer -- ADS and its potential / J.-P. Revol -- ADS history in the USA / R. L. Sheffield and E. J. Pitcher -- Accelerator driven transmutation of waste: high power accelerator for the European ADS demonstrator / J. L. Biarrotte and T. Junquera -- Myrrha, technology development for the realisation of ADS in EU: current status & prospects for realisation / R. Fernandez ... [et al.] -- High intensity proton beam production with cyclotrons / J. Grillenberger and M. Seidel -- FFAG for high intensity proton accelerator / Y. Mori -- Kaon yields for 2 to 8 GeV proton beams / K. K. Gudima, N. V. Mokhov and S. I. Striganov -- Pion yield studies for proton driver beams of 2-8 GeV kinetic energy for stopped muon and low-energy muon decay experiments / S. I. Striganov -- J-Parc accelerator status and future plans / H. Kobayashi -- Simulation and verification of DPA in materials / N. V. Mokhov, I. L. Rakhno and S. I. Striganov -- Performance and operational experience of the CNGS facility / E. Gschwendtner -- Particle physics enabled with super-conducting RF technology - summary of working group 1 / D. Jaffe and R. Tschirhart -- Proton beam requirements for a neutrino factory and muon collider / M. S. Zisman -- Proton bunching options / R. B. Palmer -- CW SRF H linac as a proton driver for muon colliders and neutrino factories / M. Popovic, C. M. Ankenbrandt and R. P. Johnson -- Rapid cycling synchrotron option for Project X / W. Chou -- Linac-based proton driver for a neutrino factory / R. Garoby ... [et al.] -- Pion production for neutrino factories and muon colliders / N. V. Mokhov ... [et al.] -- Proton bunch compression strategies / V. Lebedev -- Accelerator test facility for muon collider and neutrino factory R&D / V. Shiltsev -- The superconducting RF linac for muon

  18. Impact of Hydroxychloroquine-Loaded Polyurethane Intravaginal Rings on Lactobacilli

    PubMed Central

    Traore, Yannick Leandre; Chen, Yufei; Bernier, Anne-Marie

    2015-01-01

    The use of polymeric devices for controlled sustained delivery of drugs is a promising approach for the prevention of HIV-1 infection. Unfortunately, certain microbicides, when topically applied vaginally, may be cytotoxic to vaginal epithelial cells and the protective microflora present within the female genital tract. In this study, we evaluated the impact of hydroxychloroquine (HCQ)-loaded, reservoir-type, polyurethane intravaginal rings (IVRs) on the growth of Lactobacillus crispatus and Lactobacillus jensenii and on the viability of vaginal and ectocervical epithelial cells. The IVRs were fabricated using hot-melt injection molding and were capable of providing controlled release of HCQ for 24 days, with mean daily release rates of 17.01 ± 3.6 μg/ml in sodium acetate buffer (pH 4) and 29.45 ± 4.84 μg/ml in MRS broth (pH 6.2). Drug-free IVRs and the released HCQ had no significant effects on bacterial growth or the viability of vaginal or ectocervical epithelial cells. Furthermore, there was no significant impact on the integrity of vaginal epithelial cell monolayers, in comparison with controls, as measured by transepithelial electrical resistance. Overall, this is the first study to evaluate the effects of HCQ-loaded IVRs on the growth of vaginal flora and the integrity of vaginal epithelial cell monolayers. PMID:26416871

  19. BEAM LOSS MECHANISMS IN HIGH INTENSITY LINACS

    SciTech Connect

    Plum, Michael A

    2012-01-01

    In the present operation of the Oak Ridge Spallation Neutron Source, 60-Hz, 825-us H beam pulses are accelerated to 910 MeV, and then compressed to less than a microsecond in the storage ring, to deliver 1 MW of beam power to the spallation target. The beam loss in the superconducting portion of the linac is higher than expected, and it has shown a surprising counter-intuitive correlation with quadrupole magnetic fields, with a loss minimum occurring when the quadrupoles are set to approximately half their design values. This behavior can now be explained by a recent set of experiments that show the beam loss is primarily due to intra-beam stripping. Beam halo is another important beam loss contributor, and collimation in the 2.5 MeV Medium Energy Beam Transport has proven to be an effective mitigation strategy. In this presentation, we will summarize these and other beam loss mechanisms that are important for high intensity linacs.

  20. High-Intensity Sweeteners and Energy Balance

    PubMed Central

    Swithers, Susan E.; Martin, Ashley A.; Davidson, Terry L.

    2010-01-01

    Recent epidemiological evidence points to a link between a variety of negative health outcomes (e.g. metabolic syndrome, diabetes and cardiovascular disease) and the consumption of both calorically sweetened beverages and beverages sweetened with high-intensity, non-caloric sweeteners. Research on the possibility that non-nutritive sweeteners promote food intake, body weight gain, and metabolic disorders has been hindered by the lack of a physiologically-relevant model that describes the mechanistic basis for these outcomes. We have suggested that based on Pavlovian conditioning principles, consumption of non-nutritive sweeteners could result in sweet tastes no longer serving as consistent predictors of nutritive postingestive consequences. This dissociation between the sweet taste cues and the caloric consequences could lead to a decrease in the ability of sweet tastes to evoke physiological responses that serve to regulate energy balance. Using a rodent model, we have found that intake of foods or fluids containing non-nutritive sweeteners was accompanied by increased food intake, body weight gain, accumulation of body fat, and weaker caloric compensation, compared to consumption of foods and fluids containing glucose. Our research also provided evidence consistent with the hypothesis that these effects of consuming saccharin may be associated with a decrement in the ability of sweet taste to evoke thermic responses, and perhaps other physiological, cephalic phase, reflexes that are thought to help maintain energy balance. PMID:20060008

  1. High-intensity sweeteners and energy balance.

    PubMed

    Swithers, Susan E; Martin, Ashley A; Davidson, Terry L

    2010-04-26

    Recent epidemiological evidence points to a link between a variety of negative health outcomes (e.g. metabolic syndrome, diabetes and cardiovascular disease) and the consumption of both calorically sweetened beverages and beverages sweetened with high-intensity, non-caloric sweeteners. Research on the possibility that non-nutritive sweeteners promote food intake, body weight gain, and metabolic disorders has been hindered by the lack of a physiologically-relevant model that describes the mechanistic basis for these outcomes. We have suggested that based on Pavlovian conditioning principles, consumption of non-nutritive sweeteners could result in sweet tastes no longer serving as consistent predictors of nutritive postingestive consequences. This dissociation between the sweet taste cues and the caloric consequences could lead to a decrease in the ability of sweet tastes to evoke physiological responses that serve to regulate energy balance. Using a rodent model, we have found that intake of foods or fluids containing non-nutritive sweeteners was accompanied by increased food intake, body weight gain, accumulation of body fat, and weaker caloric compensation, compared to consumption of foods and fluids containing glucose. Our research also provided evidence consistent with the hypothesis that these effects of consuming saccharin may be associated with a decrement in the ability of sweet taste to evoke thermic responses, and perhaps other physiological, cephalic phase, reflexes that are thought to help maintain energy balance.

  2. Portable, high intensity isotopic neutron source provides increased experimental accuracy

    NASA Technical Reports Server (NTRS)

    Mohr, W. C.; Stewart, D. C.; Wahlgren, M. A.

    1968-01-01

    Small portable, high intensity isotopic neutron source combines twelve curium-americium beryllium sources. This high intensity of neutrons, with a flux which slowly decreases at a known rate, provides for increased experimental accuracy.

  3. Impacts to the chest of PMHSs - Influence of impact location and load distribution on chest response.

    PubMed

    Holmqvist, Kristian; Svensson, Mats Y; Davidsson, Johan; Gutsche, Andreas; Tomasch, Ernst; Darok, Mario; Ravnik, Dean

    2016-02-01

    The chest response of the human body has been studied for several load conditions, but is not well known in the case of steering wheel rim-to-chest impact in heavy goods vehicle frontal collisions. The aim of this study was to determine the response of the human chest in a set of simulated steering wheel impacts. PMHS tests were carried out and analysed. The steering wheel load pattern was represented by a rigid pendulum with a straight bar-shaped front. A crash test dummy chest calibration pendulum was utilised for comparison. In this study, a set of rigid bar impacts were directed at various heights of the chest, spanning approximately 120mm around the fourth intercostal space. The impact energy was set below a level estimated to cause rib fracture. The analysed results consist of responses, evaluated with respect to differences in the impacting shape and impact heights on compression and viscous criteria chest injury responses. The results showed that the bar impacts consistently produced lesser scaled chest compressions than the hub; the Middle bar responses were around 90% of the hub responses. A superior bar impact provided lesser chest compression; the average response was 86% of the Middle bar response. For inferior bar impacts, the chest compression response was 116% of the chest compression in the middle. The damping properties of the chest caused the compression to decrease in the high speed bar impacts to 88% of that in low speed impacts. From the analysis it could be concluded that the bar impact shape provides lower chest criteria responses compared to the hub. Further, the bar responses are dependent on the impact location of the chest. Inertial and viscous effects of the upper body affect the responses. The results can be used to assess the responses of human substitutes such as anthropomorphic test devices and finite element human body models, which will benefit the development process of heavy goods vehicle safety systems. Copyright © 2015

  4. High intensity laser interactions with atomic clusters

    SciTech Connect

    Ditmire, T

    2000-08-07

    The development of ultrashort pulse table top lasers with peak pulse powers in excess of 1 TW has permitted an access to studies of matter subject to unprecedented light intensities. Such interactions have accessed exotic regimes of multiphoton atomic and high energy-density plasma physics. Very recently, the nature of the interactions between these very high intensity laser pulses and atomic clusters of a few hundred to a few thousand atoms has come under study. Such studies have found some rather unexpected results, including the striking finding that these interactions appear to be more energetic than interactions with either single atoms or solid density plasmas. Recent experiments have shown that the explosion of such clusters upon intense irradiation can expel ions from the cluster with energies from a few keV to nearly 1 MeV. This phenomenon has recently been exploited to produce DD fusion neutrons in a gas of exploding deuterium clusters. Under this project, we have undertaken a general study of the intense femtosecond laser cluster interaction. Our goal is to understand the macroscopic and microscopic coupling between the laser and the clusters with the aim of optimizing high flux fusion neutron production from the exploding deuterium clusters or the x-ray yield in the hot plasmas that are produced in this interaction. In particular, we are studying the physics governing the cluster explosions. The interplay between a traditional Coulomb explosion description of the cluster disassembly and a plasma-like hydrodynamic explosion is not entirely understood, particularly for small to medium sized clusters (<1000 atoms) and clusters composed of low-Z atoms. We are focusing on experimental studies of the ion and electron energies resulting from such explosions through various experimental techniques. We are also examining how an intense laser pulse propagates through a dense medium containing these clusters.

  5. High intensity neutrino oscillation facilities in Europe

    DOE PAGES

    Edgecock, T. R.; Caretta, O.; Davenne, T.; ...

    2013-02-20

    The EUROnu project has studied three possible options for future, high intensity neutrino oscillation facilities in Europe. The first is a Super Beam, in which the neutrinos come from the decay of pions created by bombarding targets with a 4 MW proton beam from the CERN High Power Superconducting Proton Linac. The far detector for this facility is the 500 kt MEMPHYS water Cherenkov, located in the Fréjus tunnel. The second facility is the Neutrino Factory, in which the neutrinos come from the decay of μ+ and μ– beams in a storage ring. The far detector in this case ismore » a 100 kt magnetized iron neutrino detector at a baseline of 2000 km. The third option is a Beta Beam, in which the neutrinos come from the decay of beta emitting isotopes, in particular 6He and 18Ne, also stored in a ring. The far detector is also the MEMPHYS detector in the Fréjus tunnel. EUROnu has undertaken conceptual designs of these facilities and studied the performance of the detectors. Based on this, it has determined the physics reach of each facility, in particular for the measurement of CP violation in the lepton sector, and estimated the cost of construction. These have demonstrated that the best facility to build is the Neutrino Factory. Furthermore, if a powerful proton driver is constructed for another purpose or if the MEMPHYS detector is built for astroparticle physics, the Super Beam also becomes very attractive.« less

  6. High Intensity Organic Light-emitting Diodes

    NASA Astrophysics Data System (ADS)

    Qi, Xiangfei

    This thesis is dedicated to the fabrication, modeling, and characterization to achieve high efficiency organic light-emitting diodes (OLEDs) for illumination applications. Compared to conventional lighting sources, OLEDs enabled the direct conversion of electrical energy into light emission and have intrigued the world's lighting designers with the long-lasting, highly efficient illumination. We begin with a brief overview of organic technology, from basic organic semiconductor physics, to its application in optoelectronics, i.e. light-emitting diodes, photovoltaics, photodetectors and thin-film transistors. Due to the importance of phosphorescent materials, we will focus on the photophysics of metal complexes that is central to high efficiency OLED technology, followed by a transient study to examine the radiative decay dynamics in a series of phosphorescent platinum binuclear complexes. The major theme of this thesis is the design and optimization of a novel architecture where individual red, green and blue phosphorescent OLEDs are vertically stacked and electrically interconnected by the compound charge generation layers. We modeled carrier generation from the metal-oxide/doped organic interface based on a thermally assisted tunneling mechanism. The model provides insights to the optimization of a stacked OLED from both electrical and optical point of view. To realize the high intensity white lighting source, the efficient removal of heat is of a particular concern, especially in large-area devices. A fundamental transfer matrix analysis is introduced to predict the thermal properties in the devices. The analysis employs Laplace transforms to determine the response of the system to the combined effects of conduction, convection, and radiation. This perspective of constructing transmission matrices greatly facilitates the calculation of transient coupled heat transfer in a general multi-layer composite. It converts differential equations to algebraic forms, and

  7. High intensity neutrino oscillation facilities in Europe

    SciTech Connect

    Edgecock, T. R.; Caretta, O.; Davenne, T.; Densam, C.; Fitton, M.; Kelliher, D.; Loveridge, P.; Machida, S.; Prior, C.; Rogers, C.; Rooney, M.; Thomason, J.; Wilcox, D.; Wildner, E.; Efthymiopoulos, I.; Garoby, R.; Gilardoni, S.; Hansen, C.; Benedetto, E.; Jensen, E.; Kosmicki, A.; Martini, M.; Osborne, J.; Prior, G.; Stora, T.; Melo Mendonca, T.; Vlachoudis, V.; Waaijer, C.; Cupial, P.; Chance, A.; Longhin, A.; Payet, J.; Zito, M.; Baussan, E.; Bobeth, C.; Bouquerel, E.; Dracos, M.; Gaudiot, G.; Lepers, B.; Osswald, F.; Poussot, P.; Vassilopoulos, N.; Wurtz, J.; Zeter, V.; Bielski, J.; Kozien, M.; Lacny, L.; Skoczen, B.; Szybinski, B.; Ustrycka, A.; Wroblewski, A.; Marie-Jeanne, M.; Balint, P.; Fourel, C.; Giraud, J.; Jacob, J.; Lamy, T.; Latrasse, L.; Sortais, P.; Thuillier, T.; Mitrofanov, S.; Loiselet, M.; Keutgen, Th.; Delbar, Th.; Debray, F.; Trophine, C.; Veys, S.; Daversin, C.; Zorin, V.; Izotov, I.; Skalyga, V.; Burt, G.; Dexter, A. C.; Kravchuk, V. L.; Marchi, T.; Cinausero, M.; Gramegna, F.; De Angelis, G.; Prete, G.; Collazuol, G.; Laveder, M.; Mazzocco, M.; Mezzetto, M.; Signorini, C.; Vardaci, E.; Di Nitto, A.; Brondi, A.; La Rana, G.; Migliozzi, P.; Moro, R.; Palladino, V.; Gelli, N.; Berkovits, D.; Hass, M.; Hirsh, T. Y.; Schaumann, M.; Stahl, A.; Wehner, J.; Bross, A.; Kopp, J.; Neuffer, D.; Wands, R.; Bayes, R.; Laing, A.; Soler, P.; Agarwalla, S. K.; Cervera Villanueva, A.; Donini, A.; Ghosh, T.; Gomez Cadenas, J. J.; Hernandez, P.; Martin-Albo, J.; Mena, O.; Burguet-Castell, J.; Agostino, L.; Buizza-Avanzini, M.; Marafini, M.; Patzak, T.; Tonazzo, A.; Duchesneau, D.; Mosca, L.; Bogomilov, M.; Karadzhov, Y.; Matev, R.; Tsenov, R.; Akhmedov, E.; Blennow, M.; Lindner, M.; Schwetz, T.; Fernandez Martinez, E.; Maltoni, M.; Menendez, J.; Giunti, C.; Gonzalez Garcia, M. C.; Salvado, J.; Coloma, P.; Huber, P.; Li, T.; Lopez Pavon, J.; Orme, C.; Pascoli, S.; Meloni, D.; Tang, J.; Winter, W.; Ohlsson, T.; Zhang, H.; Scotto-Lavina, L.; Terranova, F.; Bonesini, M.; Tortora, L.; Alekou, A.; Aslaninejad, M.; Bontoiu, C.; Kurup, A.; Jenner, L. J.; Long, K.; Pasternak, J.; Pozimski, J.; Back, J. J.; Harrison, P.; Beard, K.; Bogacz, A.; Berg, J. S.; Stratakis, D.; Witte, H.; Snopok, P.; Bliss, N.; Cordwell, M.; Moss, A.; Pattalwar, S.; Apollonio, M.

    2013-02-20

    The EUROnu project has studied three possible options for future, high intensity neutrino oscillation facilities in Europe. The first is a Super Beam, in which the neutrinos come from the decay of pions created by bombarding targets with a 4 MW proton beam from the CERN High Power Superconducting Proton Linac. The far detector for this facility is the 500 kt MEMPHYS water Cherenkov, located in the Fréjus tunnel. The second facility is the Neutrino Factory, in which the neutrinos come from the decay of μ+ and μ beams in a storage ring. The far detector in this case is a 100 kt magnetized iron neutrino detector at a baseline of 2000 km. The third option is a Beta Beam, in which the neutrinos come from the decay of beta emitting isotopes, in particular 6He and 18Ne, also stored in a ring. The far detector is also the MEMPHYS detector in the Fréjus tunnel. EUROnu has undertaken conceptual designs of these facilities and studied the performance of the detectors. Based on this, it has determined the physics reach of each facility, in particular for the measurement of CP violation in the lepton sector, and estimated the cost of construction. These have demonstrated that the best facility to build is the Neutrino Factory. Furthermore, if a powerful proton driver is constructed for another purpose or if the MEMPHYS detector is built for astroparticle physics, the Super Beam also becomes very attractive.

  8. Wheelchair tiedown and occupant restraint loading associated with adult manual transit wheelchair in rear impact.

    PubMed

    Salipur, Zdravko; Bertocci, Gina

    2010-01-01

    Proper securement of wheelchairs in motor vehicles is vital to providing wheelchair users an adequate level of safety in a crash. Thus far, wheelchair tiedown and occupant restraint systems (WTORS) loading has mostly been examined under frontal impact conditions. Because of the inherent crash dynamic differences, rear-impact loading of WTORS is expected to differ greatly. In this study, three identical, reinforced, manual, folding, X-braced ANSI/RESNA WC19 wheelchairs were subjected to an International Organization for Standardization-proposed rear-impact crash pulse. WTORS loads (front tiedowns, rear tiedowns, lap belt, and shoulder belt) were measured and compared with frontal impact WTORS loading. Rear impact produced substantially higher loads (up to 7,851 N) in the front tiedowns than frontal impact. The rear tiedowns experienced relatively negligible loading (up to 257 N) in rear impact, while rear-impact dynamics caused the lap belt (maximum load of 1,865 N) to be loaded substantially more than the shoulder belt (maximum load of 68 N). Considering differences in frontal and rear impact WTORS loading is important to proper WTORS design and, thus, protection of wheelchair-seated occupants subjected to rear-impact events.

  9. Characterization of pediatric wheelchair kinematics and wheelchair tiedown and occupant restraint system loading during rear impact.

    PubMed

    Fuhrman, Susan I; Karg, Patricia; Bertocci, Gina

    2010-04-01

    This study characterizes pediatric wheelchair kinematic responses and wheelchair tiedown and occupant restraint system (WTORS) loading during rear impact. It also examines the kinematic and loading effects of wheelchair headrest inclusion in rear impact. In two separate rear-impact test scenarios, identical WC19-compliant manual pediatric wheelchairs were tested using a seated Hybrid III 6-year-old anthropomorphic test device (ATD) to evaluate wheelchair kinematics and WTORS loading. Three wheelchairs included no headrests, and three were equipped with slightly modified wheelchair-mounted headrests. Surrogate WTORS properly secured the wheelchairs; three-point occupant restraints properly restrained the ATD. All tests used a 26km/h, 11g rear-impact test pulse. Headrest presence affected wheelchair kinematics and WTORS loading; headrest-equipped wheelchairs had greater mean seatback deflections, mean peak front and rear tiedown loads and decreased mean lap belt loads. Rear-impact tiedown loads differed from previously measured loads in frontal impact, with comparable tiedown load levels reversed in frontal and rear impacts. The front tiedowns in rear impact had the highest mean peak loads despite lower rear-impact severity. These outcomes have implications for wheelchair and tiedown design, highlighting the need for all four tiedowns to have an equally robust design, and have implications in the development of rear-impact wheelchair transportation safety standards.

  10. Characterization of focal muscle compression under impact loading

    NASA Astrophysics Data System (ADS)

    Butler, B. J.; Sory, D. R.; Nguyen, T.-T. N.; Proud, W. G.; Williams, A.; Brown, K. A.

    2017-01-01

    In modern wars over 70% of combat wounds are to the extremities. These injuries are characterized by disruption and contamination of the limb soft tissue envelope. The extent of this tissue trauma and contamination determine the outcome of the extremity injury. In military injury, common post-traumatic complications at amputation sites include heterotopic ossification (formation of bone in soft tissue), and severe soft tissue and bone infections. We are currently developing a model of soft tissue injury that recreates pathologies observed in combat injuries. Here we present characterization of a controlled focal compression of the rabbit flexor carpi ulnaris (FCU) muscle group. The FCU was previously identified as a suitable site for studying impact injury because its muscle belly can easily be mobilized from the underlying bone without disturbing anatomical alignment in the limb. We show how macroscopic changes in tissue organization, as visualized using optical microscopy, can be correlated with data from temporally resolved traces of loading conditions.

  11. A protocol for a randomised controlled trial of the bone response to impact loading or resistance training in young women with lower than average bone mass: the OPTIMA-Ex trial

    PubMed Central

    Lambert, Conor; Beck, Belinda R; Harding, Amy T; Watson, Steven L; Weeks, Benjamin K

    2017-01-01

    Introduction The aim of the Osteoporosis Prevention Through Impact and Muscle-loading Approaches to Exercise trial is to compare the bone response to two known osteogenic stimuli — impact loading exercise and resistance training. Specifically, we will examine the effect of a 10-month, twice-weekly, high-intensity impact loading exercise intervention and a 10-month, twice-weekly, high-intensity resistance training intervention on bone mass and strength at clinically important skeletal sites. The intervention groups will be compared against a home-based ‘positive’ control group. Safety and acceptability of each exercise modality will also be determined. Methods and analysis Sedentary otherwise healthy young women aged 18–30 years with bone mineral density (BMD) T-scores less than or equal to 0 at the hip and lumbar spine, screened for conditions and medications that influence bone and physical function, will be recruited. Eligible participants are randomised to 10-month, twice-weekly, either supervised high-intensity impact training, high-intensity resistance training or a home-based ‘positive’ control group. The primary outcome measure will be lumbar spine areal BMD, while secondary outcome measures will include: whole body, femoral neck and regional measures (upper and lower limb) of bone, muscle and fat; anthropometrics; muscle strength and power; quality of life and exercise safety, enjoyment and acceptability. All outcome measures will be conducted at baseline (T0) and 10 months (T10) and will be analysed according to the intention-to-treat principle and per protocol. Ethics and dissemination The study has been granted ethical approval from the Griffith University Human Research Ethics Committee (GU Ref: 2015/775). Standard scientific reporting practices will occur, including publication in peer-reviewed journals. Participant confidentiality will be maintained in all forms of reporting. Trial registration number ACTRN12616001444471. PMID:28864705

  12. Fermilab main injector: High intensity operation and beam loss control

    NASA Astrophysics Data System (ADS)

    Brown, Bruce C.; Adamson, Philip; Capista, David; Chou, Weiren; Kourbanis, Ioanis; Morris, Denton K.; Seiya, Kiyomi; Wu, Guan Hong; Yang, Ming-Jen

    2013-07-01

    From 2005 through 2012, the Fermilab Main Injector provided intense beams of 120 GeV protons to produce neutrino beams and antiprotons. Hardware improvements in conjunction with improved diagnostics allowed the system to reach sustained operation at 400 kW beam power. Transmission was very high except for beam lost at or near the 8 GeV injection energy where 95% beam transmission results in about 1.5 kW of beam loss. By minimizing and localizing loss, residual radiation levels fell while beam power was doubled. Lost beam was directed to either the collimation system or to the beam abort. Critical apertures were increased while improved instrumentation allowed optimal use of available apertures. We will summarize the improvements required to achieve high intensity, the impact of various loss control tools and the status and trends in residual radiation in the Main Injector.

  13. Experimental Study on Impact Load on a Dam Due to Debris Flow

    Treesearch

    lwao Miyoshi

    1991-01-01

    When a dam is struck by mud or debris flow, it is put under a great impact load and sometimes is destroyed. To prevent such destruction, it is important to perform basic research about the impact load on a dam due to debris flow. Thus, we have made an experimental study and tried to establish a method to estimate such a impact load on the dam. The experiment was...

  14. High-Intensity Intermittent Exercise: Effect on Young People's Cardiometabolic Health and Cognition.

    PubMed

    Cooper, Simon B; Dring, Karah J; Nevill, Mary E

    2016-01-01

    With only a quarter of young people currently meeting physical activity guidelines, two key areas of concern are the effects of exercise on cardiometabolic health and cognition. Despite the fact that physical activity in young people is typically high intensity and intermittent in nature, much of the literature examines traditional endurance-type exercise. This review provides an update on the effects of high-intensity intermittent exercise on young people's cardiometabolic health and cognition. High-intensity intermittent exercise has acute beneficial effects on endothelial function and postprandial lipemia and chronic positive effects on weight management. In addition, there is emerging evidence regarding chronic benefits on the blood lipid profile, blood pressure, and proinflammatory and anti-inflammatory cytokines. Furthermore, emerging evidence suggests beneficial acute and chronic effects of high-intensity intermittent exercise on cognition. However, further research is required in both cardiometabolic health and cognition, particularly regarding the impact of school-based interventions in adolescents.

  15. Effect of Impaction Sequence on Osteochondral Graft Damage: The Role of Repeated and Varying Loads

    PubMed Central

    Kang, Richard W.; Friel, Nicole A.; Williams, James M.; Cole, Brian J.; Wimmer, Markus A.

    2013-01-01

    Background Osteochondral autografts and allografts require mechanical force for proper graft placement into the defect site; however, impaction compromises the tissue. This study aimed to determine the effect of impaction force and number of hits to seat the graft on cartilage integrity. Hypothesis Under constant impulse conditions, higher impaction load magnitudes are more detrimental to cell viability, matrix integrity and collagen network organization and will result in proteoglycan loss and nitric oxide release. Study Design Controlled laboratory study Methods Osteochondral explants, harvested from fresh bovine trochleas, were exposed to a series of consistent impact loads delivered by a pneumatically driven device. Each plug received the same overall impulse of 7 Ns, reflecting the mean of 23 clinically inserted plugs. Impaction loads of 37.5N, 75N, 150N, and 300N were matched with 74, 37, 21, and 11 hits respectively. Following impaction, the plugs were harvested and cartilage was analyzed for cell viability, histology by safranin-o and picosirius red, and release of sulfated glycosaminoglycans and nitric oxide. Data were compared with non-impacted control. Results Impacted plugs had significantly lower cell viability than non-impacted plugs. A dose response relationship in loss of cell viability with respect to load magnitude was seen immediately and after 4 days but lost after 8 days. Histologic analysis revealed intact cartilage surface in all samples (loaded or control), with loaded samples showing alterations in birefringence. While the sulfated GAG release was similar across varying impaction loads, release of nitric oxide increased with increasing impaction magnitudes and time. Conclusions Impaction loading parameters have a direct effect on the time course of the viability of the cartilage in the graft tissue. Clinical Relevance Optimal loading parameters for surgical impaction of osteochondral grafts are those with lower load magnitudes and a greater

  16. Impact of sampling strategy on stream load estimates in till landscape of the Midwest

    USGS Publications Warehouse

    Vidon, P.; Hubbard, L.E.; Soyeux, E.

    2009-01-01

    Accurately estimating various solute loads in streams during storms is critical to accurately determine maximum daily loads for regulatory purposes. This study investigates the impact of sampling strategy on solute load estimates in streams in the US Midwest. Three different solute types (nitrate, magnesium, and dissolved organic carbon (DOC)) and three sampling strategies are assessed. Regardless of the method, the average error on nitrate loads is higher than for magnesium or DOC loads, and all three methods generally underestimate DOC loads and overestimate magnesium loads. Increasing sampling frequency only slightly improves the accuracy of solute load estimates but generally improves the precision of load calculations. This type of investigation is critical for water management and environmental assessment so error on solute load calculations can be taken into account by landscape managers, and sampling strategies optimized as a function of monitoring objectives. ?? 2008 Springer Science+Business Media B.V.

  17. Characterization of Focal Muscle Compression Under Impact Loading

    NASA Astrophysics Data System (ADS)

    Butler, Ben; Sory, David; Nguyen, Thuy-Tien; Curry, Richard; Clasper, Jon; Proud, William; Williams, Alun; Brown, Kate

    2015-06-01

    The pattern of battle injuries sustained in modern wars shows that over 70% of combat wounds are to the extremities. These injuries are characterized by disruption and contamination of the limb soft tissue envelope. The extent of this tissue trauma and contamination determine the outcome in extremity injury. In military injury, common post-traumatic complications at amputation sites include heterotopic ossification (formation of bone in soft tissue), and severe soft tissue and bone infections. We are currently developing a model of soft tissue injury that recreates pathologies observed in combat injuries. Here we present characterization of a controlled focal compression of the rabbit flexor carpi ulnaris (FCU) muscle group. The FCU was previously identified as a suitable site for studying impact injury because its muscle belly can easily be mobilized from the underlying bone without disturbing anatomical alignment in the limb. We show how macroscopic changes in tissue organization, as visualized using optical microscopy, can be correlated with data from temporally resolved traces of loading conditions. Funding provided by the Royal British Legion.

  18. Flexible pressure sensors for smart protective clothing against impact loading

    NASA Astrophysics Data System (ADS)

    Wang, Fei; Zhu, Bo; Shu, Lin; Tao, Xiaoming

    2014-01-01

    The development of smart protective clothing will facilitate the quick detection of injuries from contact sports, traffic collisions and other accidents. To obtain real-time information like spatial and temporal pressure distributions on the clothing, flexible pressure sensor arrays are required. Based on a resistive fabric strain sensor we demonstrate all flexible, resistive pressure sensors with a large workable pressure range (0-8 MPa), a high sensitivity (1 MPa-1) and an excellent repeatability (lowest non-repeatability ±2.4% from 0.8 to 8 MPa) that can be inexpensively fabricated using fabric strain sensors and biocompatible polydimethylsiloxane (PDMS). The pressure sensitivity is tunable by using elastomers with different elasticities or by the pre-strain control of fabric strain sensors. Finite element simulation further confirms the sensor design. The simple structure, large workable pressure range, high sensitivity, high flexibility, facile fabrication and low cost of these pressure sensors make them promising candidates for smart protective clothing against impact loading.

  19. Study on Impact Loading and Humerus Injury for Baseball

    NASA Astrophysics Data System (ADS)

    Sakai, Shinobu; Oda, Juhachi; Yonemura, Shigeru; Sakamoto, Jiro

    In the United States and Japan, baseball is a very popular sport played by many people. However, the ball used is hard and moves fast. A professional baseball pitcher in good form can throw a ball at speeds upwards of 41.7m/s (150km/hr). If a ball at this speed hits the batter, serious injury can occur. In this paper we will describe our investigations on the impact of a baseball with living tissues by finite element analysis. Baseballs were projected at a load cell plate using a specialized pitching machine. The dynamic properties of the baseball were determined by comparing the wall-ball collision experimentally measuring the time history of the force and the displacement using dynamic finite element analysis software (ANSYS/ LS-DYNA). The finite element model representing a human humerus and its surrounding tissue was simulated for balls pitched at variable speeds and pitch types (knuckle and fastball). In so doing, the stress distribution and stress wave in the bone and soft tissue were obtained. From the results, the peak stress of the bone nearly yielded to the stress caused by a high fast ball. If the collision position or direction is moved from the center of the upper arm, it is assumed that the stress exuded on the humerus will be reduced. Some methods to reduce the severity of the injury which can be applied in actual baseball games are also discussed.

  20. Androgynous, Reconfigurable Closed Loop Feedback Controlled Low Impact Docking System With Load Sensing Electromagnetic Capture Ring

    NASA Technical Reports Server (NTRS)

    Lewis, James L. (Inventor); Carroll, Monty B. (Inventor); Morales, Ray H. (Inventor); Le, Thang D. (Inventor)

    2002-01-01

    The present invention relates to a fully androgynous, reconfigurable closed loop feedback controlled low impact docking system with load sensing electromagnetic capture ring. The docking system of the present invention preferably comprises two Docking- assemblies, each docking assembly comprising a load sensing ring having an outer face, one of more electromagnets, one or more load cells coupled to said load sensing ring. The docking assembly further comprises a plurality of actuator arms coupled to said load sensing ring and capable of dynamically adjusting the orientation of said load sensing ring and a reconfigurable closed loop control system capable of analyzing signals originating from said plurality of load cells and of outputting real time control for each of the actuators. The docking assembly of the present invention incorporates an active load sensing system to automatically dynamically adjust the load sensing ring during capture instead of requiring significant force to push and realign the ring.

  1. Anthropometric, Sprint, and High-Intensity Running Profiles of English Academy Rugby Union Players by Position.

    PubMed

    Darrall-Jones, Joshua D; Jones, Ben; Till, Kevin

    2016-05-01

    The purpose of this study was to evaluate the anthropometric, sprint, and high-intensity running profiles of English academy rugby union players by playing positions, and to investigate the relationships between anthropometric, sprint, and high-intensity running characteristics. Data were collected from 67 academy players after the off-season period and consisted of anthropometric (height, body mass, sum of 8 skinfolds [∑SF]), 40-m linear sprint (5-, 10-, 20-, and 40-m splits), the Yo-Yo intermittent recovery test level 1 (Yo-Yo IRTL-1), and the 30-15 intermittent fitness test (30-15 IFT). Forwards displayed greater stature, body mass, and ∑SF; sprint times and sprint momentum, with lower high-intensity running ability and sprint velocities than backs. Comparisons between age categories demonstrated body mass and sprint momentum to have the largest differences at consecutive age categories for forwards and backs; whereas 20-40-m sprint velocity was discriminate for forwards between under 16s, 18s, and 21s. Relationships between anthropometric, sprint velocity, momentum, and high-intensity running ability demonstrated body mass to negatively impact on sprint velocity (10 m; r = -0.34 to -0.46) and positively affect sprint momentum (e.g., 5 m; r = 0.85-0.93), with large to very large negative relationships with the Yo-Yo IRTL-1 (r = -0.65 to -0.74) and 30-15 IFT (r = -0.59 to -0.79). These findings suggest that there are distinct anthropometric, sprint, and high-intensity running ability differences between and within positions in junior rugby union players. The development of sprint and high-intensity running ability may be impacted by continued increases in body mass as there seems to be a trade-off between momentum, velocity, and the ability to complete high-intensity running.

  2. Physiological responses at the lactate-minimum-intensity with and without prior high-intensity exercise.

    PubMed

    Zagatto, Alessandro Moura; Padulo, Johnny; Silva, Adelino Ramos Sanchez da; Müller, Paulo de Tarso Guerrero; Miyagi, Willian Eiji; Gobatto, Claudio Alexandre

    2016-11-01

    This study examined the physiological responses during exercise-to-exhaustion at the lactate-minimum-intensity with and without prior high-intensity exercise. Eleven recreationally trained males performed a graded exercise test, a lactate minimum test and two constant-load tests at lactate-minimum-intensity until exhaustion, which were applied with or without prior hyperlactatemia induction (i.e., 30-s Wingate test). The physiological responses were significantly different (P < 0.05) between constant-load tests for pulmonary ventilation ([Formula: see text]), blood-lactate-concentration ([La(-)]), pH, bicarbonate concentration ([HCO3]) and partial pressure of carbon dioxide during the initial minutes. The comparisons within constant-load tests showed steady state behaviour for oxygen uptake and the respiratory exchange ratio, but heart rate and rating of perceived exertion increased significantly during both exercise conditions, while the [Formula: see text] increased only during constant-load effort. During effort performed after high-intensity exercise: [Formula: see text], [La(-)], pH and [HCO3] differed at the start of exercise compared to another condition but were similar at the end (P > 0.05). In conclusion, the constant-load exercises performed at lactate-minimum-intensity with or without prior high-intensity exercise did not lead to the steady state of all analysed parameters; however, variables such as [La(-)], pH and [HCO3] - altered at the beginning of effort performed after high-intensity exercise - were reestablished after approximately 30 min of exercise.

  3. Impact of Chloroquine on Viral Load in Breast Milk

    PubMed Central

    Semrau, Katherine; Kuhn, Louise; Kasonde, Prisca; Sinkala, Moses; Kankasa, Chipepo; Shutes, Erin; Vwalika, Cheswa; Ghosh, Mrinal; Aldrovandi, Grace; Thea, Donald M.

    2006-01-01

    Summary The anti-malarial agent chloroquine has activity against HIV. We compared the effect of chloroquine (n = 18) to an anti-malarial agent without known anti-HIV-activity, sulfadoxine-pyrimethamine (n = 12), on breast milk HIV RNA levels among HIV-infected breastfeeding women in Zambia. After adjusting for CD4 count and plasma viral load, chloroquine was associated with a trend towards lower levels of HIV RNA in breast milk compared with sulfadoxine-pyrimethamine (P 0.05). Higher breastmilk viral load was also observed among women receiving presumptive treatment = for symptomatic malaria compared with asymptomatic controls and among controls reporting fever in the prior week. Further research is needed to determine the potential role of chloroquine in prevention of HIV transmission through breastfeeding. Impacte de la chloroquine sur la charge virale dans le lait maternelle La chloroquine, agent antimalarique, a une activité contre le VIH. Nous avons comparé l’effet de la chloroquine à celui d’un autre agent antimalarique, la sulfadoxine-pyrimethamine, dont l’activité sur le VIH n’est pas connue, en mesurant les taux d’ARN de VIH dans le lait maternel de femmes allaitantes infectées par le VIH en Zambie. Après ajustement pour les taux de CD4 et la charge virale dans le plasma, la chloroquine comparée à la sulfadoxine pyrimethamine était associée à une tendance vers des teneurs plus bas en ARN de VIH dans le lait maternel (P = 0,05). Des charges virales plus élevées dans le lait maternel étaient aussi observées chez des femmes recevant un traitement présomptif pour des symptômes de malaria par rapport aux contrôles asymptomatiques et par rapport à des contrôles rapportant de la fièvre durant la première semaine. Des études supplémentaires sont nécessaires pour déterminer le rôle potentiel de la chloroquine dans la prévention de la transmission du VIH par l’allaitement maternel. mots clésVIH, malaria, allaitement maternel

  4. Effect of cyclic impact load on shear bond strength of zirconium dioxide ceramics.

    PubMed

    Kawai, Naoko; Shinya, Akikazu; Yokoyama, Daiichiro; Gomi, Harunori; Shinya, Akiyoshi

    2011-06-01

    To investigate the influence of cyclic impact load and the number of load cycles on compressive shear bond strength under the three different cements. The following materials were used: Super Bond C&B (SB) and Panavia Fluoro Cement (PF) as adhesive resin cements, Fuji Luting (FL) as a resin-modified glass-ionomer cement, and zirconium dioxide ceramics as adherend. Before the shear bond test, three different impact loading conditions (compressive direction, shear direction, and no impact) and the number of load cycles (1 to 106 cycles), were performed. A total of 189 specimens (n = 3/group) were randomly assigned to groups and tested. A cyclic impact test was performed by applying a load of 98N at a distance of 40 mm and a loading cycle frequency of 1 Hz. All results were statistically analyzed with two-way ANOVA and Tukey's multiple comparison test. Shear bond strengths of SB, PF, and FL subjected to no cyclic impact load were 21.6 to 53.8 MPa in SB, 27.0 to 63.6 MPa in PF, and 20.0 to 35.9 MPa in FL. The shear bond strength of SB and PF increased to a certain degree from one to 105 cycles, while FL did likewise from one to 104 cycles. The shear bond strengths of SB, PF, and FL were greatest without cyclic impact, followed by compressive and then shear cyclic impact.

  5. High intensity electron cyclotron resonance proton source for low energy high intensity proton accelerator.

    PubMed

    Roychowdhury, P; Chakravarthy, D P

    2009-12-01

    Electron cyclotron resonance (ECR) proton source at 50 keV, 50 mA has been designed, developed, and commissioned for the low energy high intensity proton accelerator (LEHIPA). Plasma characterization of this source has been performed. ECR plasma was generated with 400-1100 W of microwave power at 2.45 GHz, with hydrogen as working gas. Microwave was fed in the plasma chamber through quartz window. Plasma density and temperature was studied under various operating conditions, such as microwave power and gas pressure. Langmuir probe was used for plasma characterization using current voltage variation. The typical hydrogen plasma density and electron temperature measured were 7x10(11) cm(-3) and 6 eV, respectively. The total ion beam current of 42 mA was extracted, with three-electrode extraction geometry, at 40 keV of beam energy. The extracted ion current was studied as a function of microwave power and gas pressure. Depending on source pressure and discharge power, more than 30% total gas efficiency was achieved. The optimization of the source is under progress to meet the requirement of long time operation. The source will be used as an injector for continuous wave radio frequency quadrupole, a part of 20 MeV LEHIPA. The required rms normalized emittance of this source is less than 0.2 pi mm mrad. The simulated value of normalized emittance is well within this limit and will be measured shortly. This paper presents the study of plasma parameters, first beam results, and the status of ECR proton source.

  6. High intensity electron cyclotron resonance proton source for low energy high intensity proton accelerator

    SciTech Connect

    Roychowdhury, P.; Chakravarthy, D. P.

    2009-12-15

    Electron cyclotron resonance (ECR) proton source at 50 keV, 50 mA has been designed, developed, and commissioned for the low energy high intensity proton accelerator (LEHIPA). Plasma characterization of this source has been performed. ECR plasma was generated with 400-1100 W of microwave power at 2.45 GHz, with hydrogen as working gas. Microwave was fed in the plasma chamber through quartz window. Plasma density and temperature was studied under various operating conditions, such as microwave power and gas pressure. Langmuir probe was used for plasma characterization using current voltage variation. The typical hydrogen plasma density and electron temperature measured were 7x10{sup 11} cm{sup -3} and 6 eV, respectively. The total ion beam current of 42 mA was extracted, with three-electrode extraction geometry, at 40 keV of beam energy. The extracted ion current was studied as a function of microwave power and gas pressure. Depending on source pressure and discharge power, more than 30% total gas efficiency was achieved. The optimization of the source is under progress to meet the requirement of long time operation. The source will be used as an injector for continuous wave radio frequency quadrupole, a part of 20 MeV LEHIPA. The required rms normalized emittance of this source is less than 0.2 {pi} mm mrad. The simulated value of normalized emittance is well within this limit and will be measured shortly. This paper presents the study of plasma parameters, first beam results, and the status of ECR proton source.

  7. Mathematical simulation of the behavior of materials and structural elements under multiple impact loading

    NASA Astrophysics Data System (ADS)

    Belov, N. N.; Yugov, N. T.; Kopanitsa, D. G.; Tabachenko, A. N.; Afanas'eva, S. A.; Yugov, A. A.; Arkhipov, I. N.

    2010-06-01

    A method of computer simulation is used to investigate the processes of compact cylindrical projectile penetration into steel specimens separated by air gaps during successive group impacts, impact interaction of long steel bars with an explosive screened by a system of spatially separated multilayered screens, and fracture of ferroconcrete columns under repeated longitudinal and transverse impact loading.

  8. The impact of cognitive load on delayed recall.

    PubMed

    Camos, Valérie; Portrat, Sophie

    2015-08-01

    Recent studies have suggested that long-term retention of items studied in a working memory span task depends on the refreshing of memory items-more specifically, on the number of refreshing opportunities. However, it was previously shown that refreshing depends on the cognitive load of the concurrent task introduced in the working memory span task. Thus, cognitive load should determine the long-term retention of items assessed in a delayed-recall test if such retention relies on refreshing. In two experiments, while the amount of refreshing opportunities remained constant, we varied the cognitive load of the concurrent task by either introducing tasks differing in their attentional demands or varying the pace of the concurrent task. To verify that this effect was related to refreshing and not to any maintenance mechanism, we also manipulated the availability of subvocal rehearsal. Replicating previous results, increasing cognitive load reduced immediate recall. This increase also had a detrimental effect on delayed recall. Conversely, the addition of concurrent articulation reduced immediate but not delayed recall. This study shows that both working and episodic memory traces depend on the cognitive load of the concurrent task, whereas the use of rehearsal affects only working memory performance. These findings add further evidence of the dissociation between subvocal rehearsal and attentional refreshing.

  9. Light shield and cooling apparatus. [high intensity ultraviolet lamp

    NASA Technical Reports Server (NTRS)

    Meador, T. G., Jr. (Inventor)

    1974-01-01

    A light shield and cooling apparatus was developed for a high intensity ultraviolet lamp including water and high pressure air for cooling and additional apparatus for shielding the light and suppressing the high pressure air noise.

  10. Space Station Live: High-Intensity Exercise in Space

    NASA Image and Video Library

    NASA Public Affairs Officer Lori Meggs talks with SPRINT Principal Investigator Lori Ploutz-Snyder to learn more about this high-intensity exercise research taking place aboard the International Sp...

  11. Characteristics impacting on session rating of perceived exertion training load in Australian footballers.

    PubMed

    Gallo, Tania; Cormack, Stuart; Gabbett, Tim; Williams, Morgan; Lorenzen, Christian

    2015-01-01

    The relationship between external training load and session rating of perceived exertion (s-RPE) training load and the impact that playing experience, playing position and 2-km time-trial performance had on s-RPE training load were explored. From 39 Australian Football players, 6.9 ± 4.6 training sessions were analysed, resulting in 270 samples. Microtechnology devices provided external training load (distance, average speed, high-speed running distance, player load (PL) and player loadslow (PLslow)). The external training load measures had moderate to very large associations (r, 95% CI) with s-RPE training load, average speed (0.45, 0.35-0.54), high-speed running distance (0.51, 0.42-0.59), PLslow (0.80, 0.75-0.84), PL (0.86, 0.83-0.89) and distance (0.88, 0.85-0.90). Differences were described using effect sizes (d ±95% CL). When controlling for external training load, the 4- to 5-year players had higher s-RPE training load than the 0- to 1- (0.44 ± 0.33) and 2- to 3-year players (0.51 ± 0.30), ruckmen had moderately higher s-RPE training load than midfielders (0.82 ± 0.58), and there was a 0.2% increase in s-RPE training load per 1 s increase in time-trial (95% CI: 0.07-0.34). Experience, position and time-trial performance impacted the relationship between external training load and s-RPE training load. This suggests that a given external training load may result in different internal responses between athletes, potentially leaving individuals at risk of overtraining or failing to elicit positive adaptation. It is therefore vital that coaches and trainers give consideration to these mediators of s-RPE training load.

  12. The influence of impact direction and axial loading on the bone fracture pattern.

    PubMed

    Cohen, Haim; Kugel, Chen; May, Hila; Medlej, Bahaa; Stein, Dan; Slon, Viviane; Brosh, Tamar; Hershkovitz, Israel

    2017-08-01

    The effect of the direction of the impact and the presence of axial loading on fracture patterns have not yet been established in experimental 3-point bending studies. To reveal the association between the direction of the force and the fracture pattern, with and without axial loading. A Dynatup Model POE 2000 (Instron Co.) low energy pendulum impact machine was utilized to apply impact loading on fresh pig femoral bones (n=50). The bone clamp shaft was adjusted to position the bone for three-point bending with and without additional bone compression. Four different directions of the force were applied: anterior, posterior, lateral, and medial. The impacted aspect can be distinguished from the non-impacted aspects based on the fracture pattern alone (the most fractured one); the impact point can be identified on bare bones (the area from which all oblique lines radiate and/or the presence of a chip fragment). None of our experiments (with and without compression) yielded a "true" butterfly fracture, but instead, oblique radiating lines emerged from the point of impact (also known as "false" butterfly). Impacts on the lateral and anterior aspects of the bones produce more and longer fracture lines than impacts on the contralateral side; bones subjected to an impact with axial loading are significantly more comminuted and fragmented. Under axial loading, the number of fracture lines is independent of the impact direction. Our study presents an experimental model for fracture analysis and shows that the impact direction and the presence of axial loading during impact significantly affect the fracture pattern obtained. Copyright © 2017 Elsevier B.V. All rights reserved.

  13. Modeling the Dynamic Load/Unload Behavior of Ceramics under Impact Loading

    DTIC Science & Technology

    1990-07-01

    34The Mechanics of Fracture under High-rate Stress Loading," in: A.P. Bazant , ed., Preprints of the William Prager Symposium on Mechanics of...A120 3 Ceramics," Jour. of Appl. Phy., Vol 42, Number 1, Jan 71, p 276. 8. W. Herrmann, R.J. Lawrence, and D.S. Mason, "Strain Hardening and

  14. System ID modern control algorithms for active aerodynamic load control and impact on gearbox loading.

    SciTech Connect

    Berg, Jonathan Charles; Halse, Chris; Crowther, Ashley; Barlas, Thanasis; Wilson, David Gerald; Berg, Dale E.; Resor, Brian Ray

    2010-06-01

    Prior work on active aerodynamic load control (AALC) of wind turbine blades has demonstrated that appropriate use of this technology has the potential to yield significant reductions in blade loads, leading to a decrease in wind cost of energy. While the general concept of AALC is usually discussed in the context of multiple sensors and active control devices (such as flaps) distributed over the length of the blade, most work to date has been limited to consideration of a single control device per blade with very basic Proportional Derivative controllers, due to limitations in the aeroservoelastic codes used to perform turbine simulations. This work utilizes a new aeroservoelastic code developed at Delft University of Technology to model the NREL/Upwind 5 MW wind turbine to investigate the relative advantage of utilizing multiple-device AALC. System identification techniques are used to identify the frequencies and shapes of turbine vibration modes, and these are used with modern control techniques to develop both Single-Input Single-Output (SISO) and Multiple-Input Multiple-Output (MIMO) LQR flap controllers. Comparison of simulation results with these controllers shows that the MIMO controller does yield some improvement over the SISO controller in fatigue load reduction, but additional improvement is possible with further refinement. In addition, a preliminary investigation shows that AALC has the potential to reduce off-axis gearbox loads, leading to reduced gearbox bearing fatigue damage and improved lifetimes.

  15. High Intensity Tactical Power Sources for the 1990 Army.

    DTIC Science & Technology

    conceptual or physical study which may become feasible as high intensity power sources . These considerations include present state of the art of...requirements, energy and power output capabilities, and fixed costs. From these tables, it may be seen that a variety of electrical power sources would be...required to satisfy diverse requirements, but an attempt is made to categorize possible high intensity power sources into their areas of optimum

  16. Analysis of Mesh Distribution Systems Considering Load Models and Load Growth Impact with Loops on System Performance

    NASA Astrophysics Data System (ADS)

    Kumar Sharma, A.; Murty, V. V. S. N.

    2014-12-01

    The distribution system is the final link between bulk power system and consumer end. A distinctive load flow solution method is used for analysis of the load flow of radial and weakly meshed network based on Kirchhoff's Current Law (KCL) and KVL. This method has excellent convergence characteristics for both radial as well as weakly meshed structure and is based on bus injection to branch current and branch-current to bus-voltage matrix. The main contribution of the paper is: (i) an analysis has been carried out for a weekly mesh network considering number of loops addition and its impact on the losses, kW and kVAr requirements from a system, and voltage profile, (ii) different load models, realistic ZIP load model and load growth impact on losses, voltage profile, kVA and kVAr requirements, (iii) impact of addition of loops on losses, voltage profile, kVA and kVAr requirements from substation, and (iv) comparison of system performance with radial distribution system. Voltage stability is a major concern in planning and operation of power systems. This paper also includes identifying the closeness critical bus which is the most sensitive to the voltage collapse in radial distribution networks. Node having minimum value of voltage stability index is the most sensitive node. Voltage stability index values are computed for meshed network with number of loops added in the system. The results have been obtained for IEEE 33 and 69 bus test system. The results have also been obtained for radial distribution system for comparison.

  17. SRB attrition rate study of the aft skirt due to water impact cavity collapse loading

    NASA Technical Reports Server (NTRS)

    Crockett, C. D.

    1976-01-01

    A methodology was presented so that realistic attrition prediction could aid in selecting an optimum design option for minimizing the effects of updated loads on the Space Shuttle Solid Rocket Booster (SRB) aft skirt. The updated loads resulted in water impact attrition rates greater than 10 percent for the aft skirt structure. Adding weight to reinforce the aft skirt was undesirable. The refined method treats the occurrences of the load distribution probabilistically, radially and longitudinally, with respect to the critical structural response.

  18. Load on osseointegrated fixation of a transfemoral amputee during a fall: loading, descent, impact and recovery analysis.

    PubMed

    Frossard, Laurent Alain; Tranberg, Roy; Haggstrom, Eva; Pearcy, Mark; Brånemark, Rickard

    2010-03-01

    Falling represents a health risk for lower limb amputees fitted with an osseointegrated fixation mainly because of the potential damage to the fixation. The purpose of this study was to characterize a real forward fall that occurred inadvertently to a transfemoral amputee fitted with an osseointegrated fixation while attending a gait measurement session to assess the load applied on the residuum. The objective was to analyze the load applied on the fixation with an emphasis on the sequence of events, the pattern and the magnitude of the forces and moments. The load was measured directly at 200 Hz using a six-channel transducer. Complementary video footage was also studied. The fall was divided into four phases: Loading (240 ms), descent (620 ms), impact (365 ms) and recovery (2495 ms). The main impact forces and moments occurred 870 ms and 915 ms after the heel contact, and corresponded to 133% BW and 17 % BWm, or 1.2 and 11.2 times the maximum forces and moments applied during the previous steps of the participant, respectively. This study provided key information to engineers and clinicians facing the challenge to design equipment, and rehabilitation and exercise programs to restore safely the locomotion of lower limb amputees.

  19. Installation of Impact Plates to Continuously Measure Bed Load: Elwha River, Washington, USA

    USDA-ARS?s Scientific Manuscript database

    In 2008 and 2009, a series of bed load impact plates was installed across a channel spanning weir on the Elwha River, Washington. This is the first permanent installation of its kind in North America and one of the largest anywhere. The purpose of this system is to measure coarse bed load during and...

  20. Climate Change Impacts on Residential and Commercial Loads in the Western U.S. Grid

    SciTech Connect

    Lu, Ning; Taylor, Zachary T.; Jiang, Wei; Xie, YuLong; Leung, Lai R.; Correia, James; Wong, Pak C.; Mackey, Patrick S.; Paget, Maria L.

    2008-09-30

    This report presents a multi-disciplinary modeling approach to quickly quantify climate change impacts on energy consumption, peak load, and load composition of residential and commercial buildings. This research focuses on addressing the impact of temperature changes on the building cooling load in 10 major cities across the Western United States and Canada. Our results have shown that by the mid-century, building yearly energy consumption and peak load will increase in the Southwest. Moreover, the peak load months will spread out to not only the summer months but also spring and autumn months. The Pacific Northwest will experience more hot days in the summer months. The penetration of the air conditioning (a/c) system in this area is likely to increase significantly over the years. As a result, some locations in the Pacific Northwest may be shifted from winter peaking to summer peaking. Overall, the Western U.S. grid may see more simultaneous peaks across the North and South in summer months. Increased cooling load will result in a significant increase in the motor load, which consumes more reactive power and requires stronger voltage support from the grid. This study suggests an increasing need for the industry to implement new technology to increase the efficiency of temperature-sensitive loads and apply proper protection and control to prevent possible adverse impacts of a/c motor loads.

  1. Failure to loose fear: The impact of cognitive load and trait anxiety on extinction.

    PubMed

    Raes, An K; De Raedt, Rudi; Verschuere, Bruno; De Houwer, Jan

    2009-12-01

    Exposure therapy is an effective technique for fear reduction. However, whether effective exposure requires attentional allocation to the feared situation remains a debated clinical issue. In the present study, the impact of attention allocation in extinction was investigated in an experimental conditioning study. Through a between-subjects manipulation of cognitive load, we created a condition in which participants could allocate their attention to the feared stimulus during extinction (low load condition), and a condition in which attentional allocation was impaired (high load condition). The influence of cognitive load on extinction was examined by comparing electrodermal responses and verbal ratings for the conditioned stimuli in the two extinction load conditions. The results show less successful extinction in the high load condition than in the low load condition. However, this effect was found only in low anxious participants, and it was prominent only on the skin conductance responses. The present results suggest that extinction is not automatic but requires cognitive resources.

  2. Predicting traffic load impact of alternative recreation developments

    Treesearch

    Gary H. Elsner; Ronald A. Oliveira

    1973-01-01

    Traffic load changes as a result of expansion of recreation facilities may be predicted through computations based on estimates of (a) drawing power of the recreation attracttions, overnight accommodations, and in- or out-terminals; (b) probable types of travel; (c) probable routes of travel; and (d) total number of cars in the recreation system. Once the basic model...

  3. The Impact of Cognitive Load Theory on Learning Astronomy

    NASA Astrophysics Data System (ADS)

    Foster, Thomas M.

    2010-01-01

    Every student is different, which is the challenge of astronomy education research (AER) and teaching astronomy. This difference also provides the greatest goal for education researchers - our GUT - we need to be able to quantify these differences and provide explanatory and predictive theories to curriculum developers and teachers. One educational theory that holds promise is Cognitive Load Theory. Cognitive Load Theory begins with the well-established fact that everyone's working memory can hold 7 ± 2 unique items. This quirk of the human brain is why phone numbers are 7 digits long. This quirk is also why we forget peoples’ names after just meeting them, leave the iron on when we leave the house, and become overwhelmed as students of new material. Once the intricacies of Cognitive Load are understood, it becomes possible to design learning environments to marshal the resources students have and guide them to success. Lessons learned from Cognitive Load Theory can and should be applied to learning astronomy. Classroom-ready ideas will be presented.

  4. Effects of high-intensity training and resumed training on macroelement and microelement of elite basketball athletes.

    PubMed

    Wang, Lijuan; Zhang, Jun; Wang, Jiahong; He, Wangxiao; Huang, Hongen

    2012-11-01

    The purpose of this study was to assess the effects of high-intensity training and resumed training in hot and humid environment on plasma macro- and microelements levels of elite Han Chinese basketball players. Ten well-trained elite basketball athletes' plasma macroelements (chlorin, sodium, potassium, and calcium), creatine kinase (CK), and creatine kinase-MB (CK-MB) were measured before and after a 2-h high-intensity training, and microelements (zinc, copper, iron, and selenium) were determined before and after a 1-week high-intensity training and after a 1-week resumed training. The blood CK and CK-MB levels of the elite basketball athletes were significantly increased (P < 0.05) after high-intensity basketball training. The macroelements (chlorin, sodium, and calcium) levels of blood increased significantly except potassium after high-intensity basketball training. No significant differences (P > 0.05) were found in zinc and copper levels; nevertheless, the levels of plasma selenium and plasma iron were significantly lower (P < 0.05) after a 1-week high-intensity training. After a 1-week resumed training, except zinc, all of microelements measured had a trend toward original levels. These results implicated that high-intensity training would provoke the change of macroelements which would lead to electrolyte disturbance. In addition, the present study suggested that a 1-week high-intensity training would have an impact on microelement levels, especially for selenium and iron.

  5. Friction Stir Weld Failure Mechanisms in Aluminum-Armor Structures Under Ballistic Impact Loading Conditions

    DTIC Science & Technology

    2013-01-01

    REPORT Friction Stir Weld Failure Mechanisms in Aluminum-Armor Structures Under Ballistic Impact Loading Conditions 14. ABSTRACT 16. SECURITY... Under Ballistic Impact Loading Conditions Report Title ABSTRACT A critical assessment is carried out of the microstructural changes in respect of the...microstructure and properties, and the operative failure mechanisms in different regions of the weld. Toward this end, a procedure is proposed in the

  6. Elastically suspending the screw holes of a locked osteosynthesis plate can dampen impact loads.

    PubMed

    Capanni, Felix; Hansen, Kirk; Fitzpatrick, Daniel C; Madey, Steven M; Bottlang, Michael

    2015-06-01

    Impact damping by elastic fixation is a principal engineering strategy to increase the durability of load-bearing structures exposed to prolonged dynamic loading. This biomechanical study evaluated axial impact damping provided by a novel dynamic locking plate. In this design, locking screw holes are elastically suspended within a silicone envelope inside the locking plate. Axial impact damping was assessed for 3 distinct fixation constructs applied to bridge a 10-mm fracture gap of a femoral diaphysis surrogate: a standard locking plate, a dynamic locking plate, and an Ilizarov ring fixator. First, the 3 fixation constructs were characterized by determining their axial stiffness. Subsequently, constructs were subjected to a range of axial impact loads to quantify damping of force transmission. Compared with standard locked plating constructs, dynamic plating constructs were 58% less stiff (P < .01) and Ilizarov constructs were 88% less stiff (P < .01). Impact damping correlated inversely with construct stiffness. Compared with standard plating, dynamic plating constructs and Ilizarov constructs dampened the transmission of impact loads by up to 48% (P < .01) and 74% (P < .01), respectively. In conclusion, lower construct stiffness correlated with superior damping of axial impact loads. Dynamic locking plates provide significantly greater impact damping compared with standard locking plates.

  7. Effect of preseason concurrent muscular strength and high-intensity interval training in professional soccer players.

    PubMed

    Wong, Pui-lam; Chaouachi, Anis; Chamari, Karim; Dellal, Alexandre; Wisloff, Ulrik

    2010-03-01

    This study examined the effect of concurrent muscular strength and high-intensity running interval training on professional soccer players' explosive performances and aerobic endurance. Thirty-nine players participated in the study, where both the experimental group (EG, n = 20) and control group (CG, n = 19) participated in 8 weeks of regular soccer training, with the EG receiving additional muscular strength and high-intensity interval training twice per week throughout. Muscular strength training consisted of 4 sets of 6RM (repetition maximum) of high-pull, jump squat, bench press, back half squat, and chin-up exercises. The high-intensity interval training consisted of 16 intervals each of 15-second sprints at 120% of individual maximal aerobic speed interspersed with 15 seconds of rest. EG significantly increased (p < or = 0.05) 1RM back half squat and bench press but showed no changes in body mass. Within-subject improvement was significantly higher (p < or = 0.01) in the EG compared with the CG for vertical jump height, 10-m and 30-m sprint times, distances covered in the Yo-Yo Intermittent Recovery Test and maximal aerobic speed test, and maximal aerobic speed. High-intensity interval running can be concurrently performed with high load muscular strength training to enhance soccer players' explosive performances and aerobic endurance.

  8. Aerosol loading impact on Asian monsoon precipitation patterns

    NASA Astrophysics Data System (ADS)

    Biondi, Riccardo; Cagnazzo, Chiara; Costabile, Francesca; Cairo, Francesco

    2017-04-01

    Solar light absorption by aerosols such as black carbon and dust assume a key role in driving the precipitation patterns in the Indian subcontinent. The aerosols stack up against the foothills of the Himalayas in the pre-monsoon season and several studies have already demonstrated that this can cause precipitation anomalies during summer. Despite its great significance in climate change studies, the link between absorbing aerosols loading and precipitation patterns remains highly uncertain. The main challenge for this kind of studies is to find consistent and reliable datasets. Several aerosol time series are available from satellite and ground based instruments and some precipitation datasets from satellite sensors, but they all have different time/spatial resolution and they use different assumptions for estimating the parameter of interest. We have used the aerosol estimations from the Ozone Monitoring Instrument (OMI), the Along-Track Scanning Radiometer (AATSR) and the MODerate resolution Imaging Spectroradiometer (MODIS) and validated them against the Aerosol Robotic Network (AERONET) measurements in the Indian area. The precipitation has been analyzed by using the Tropical Rainfall Measuring Mission (TRMM) estimations and the Modern-Era Retrospective analysis for Research and Applications version 2 (MERRA-2). From our results it is evident the discrepancy between the aerosol loading on the area of interest from the OMI, AATSR, and MODIS, but even between 3 different algorithms applied to the MODIS data. This uncertainty does not allow to clearly distinguishing high aerosol loading years from low aerosol loading years except in a couple of cases where all the estimations agree. Similar issues are also present in the precipitation estimations from TRMM and MERRA-2. However, all the aerosol datasets agree in defining couples of consecutive years with a large gradient of aerosol loading. Based on this assumption we have compared the precipitation anomalies and

  9. The Extravehicular Suit Impact Load Attenuation Study for Use in Astronaut Bone Fracture Prediction

    NASA Technical Reports Server (NTRS)

    Lewandowski, Beth E.; Gilkey, Kelly M.; Sulkowski, Christina M.; Samorezov, Sergey; Myers, Jerry G.

    2011-01-01

    The NASA Integrated Medical Model (IMM) assesses the risk, including likelihood and impact of occurrence, of all credible in-flight medical conditions. Fracture of the proximal femur is a traumatic injury that would likely result in loss of mission if it were to happen during spaceflight. The low gravity exposure causes decreases in bone mineral density which heightens the concern. Researchers at the NASA Glenn Research Center have quantified bone fracture probability during spaceflight with a probabilistic model. It was assumed that a pressurized extravehicular activity (EVA) suit would attenuate load during a fall, but no supporting data was available. The suit impact load attenuation study was performed to collect analogous data. METHODS: A pressurized EVA suit analog test bed was used to study how the offset, defined as the gap between the suit and the astronaut s body, impact load magnitude and suit operating pressure affects the attenuation of impact load. The attenuation data was incorporated into the probabilistic model of bone fracture as a function of these factors, replacing a load attenuation value based on commercial hip protectors. RESULTS: Load attenuation was more dependent on offset than on pressurization or load magnitude, especially at small offsets. Load attenuation factors for offsets between 0.1 - 1.5 cm were 0.69 +/- 0.15, 0.49 +/- 0.22 and 0.35 +/- 0.18 for mean impact forces of 4827, 6400 and 8467 N, respectively. Load attenuation factors for offsets of 2.8 - 5.3 cm were 0.93 +/- 0.2, 0.94 +/- 0.1 and 0.84 +/- 0.5, for the same mean impact forces. Reductions were observed in the 95th percentile confidence interval of the bone fracture probability predictions. CONCLUSIONS: The reduction in uncertainty and improved confidence in bone fracture predictions increased the fidelity and credibility of the fracture risk model and its benefit to mission design and operational decisions.

  10. A Theoretical Investigation of Hydrodynamic Impact Loads on Scalloped-Bottom Seaplanes and Comparisons with Experiment

    NASA Technical Reports Server (NTRS)

    Milwitzky, Benjamin

    1947-01-01

    An analytical method is presented for calculating the hydrodynamic impact loads and motions experienced by seaplane floats and hulls with scalloped (fluted) bottoms. The analysis treats vertical impact at zero trim in addition to the more general problem of the step impact of a seaplane at positive trim where the flight path is oblique to the keel and to the water surface. Also considered are the transformations required to represent impacts into waves.

  11. Repeated high-intensity exercise in professional rugby union.

    PubMed

    Austin, Damien; Gabbett, Tim; Jenkins, David

    2011-07-01

    The aim of the present study was to describe the frequency, duration, and nature of repeated high-intensity exercise in Super 14 rugby union. Time-motion analysis was used during seven competition matches over the 2008 and 2009 Super 14 seasons; five players from each of four positional groups (front row forwards, back row forwards, inside backs, and outside backs) were assessed (20 players in total). A repeated high-intensity exercise bout was considered to involve three or more sprints, and/or tackles and/or scrum/ruck/maul activities within 21 s during the same passage of play. The range of repeated high-intensity exercise bouts for each group in a match was as follows: 11-18 for front row forwards, 11-21 for back row forwards, 13-18 for inside backs, and 2-11 for outside backs. The durations of the most intense repeated high-intensity exercise bouts for each position ranged from 53 s to 165 s and the minimum recovery periods between repeated high-intensity exercise bouts ranged from 25 s for the back row forwards to 64 s for the front row forwards. The present results show that repeated high-intensity exercise bouts vary in duration and activities relative to position but all players in a game will average at least 10 changes in activity in the most demanding bouts and complete at least one tackle and two sprints. The most intense periods of activity are likely to last as long as 120 s and as little as 25 s recovery may separate consecutive repeated high-intensity exercise bouts. The present findings can be used by coaches to prepare their players for the most demanding passages of play likely to be experienced in elite rugby union.

  12. Mechanical Behaviour of Bolted Joints Under Impact Rates of Loading

    DTIC Science & Technology

    2012-01-01

    lost during testing. Experimental results show 95% confidence error bars for 4 specimens. The FEM results show an average of five calculations of...the same e/d configuration to reduce the bias of human calculation of takeoff and landing of incident, reflected, and transmission waves. The FEM ...the loading rate of the specimen as shown in Figure 2.3. Five FEM simulations for e/d of 1, 2, 3, 4 were run using ABAQUS and averaged to smooth any

  13. Assessment of dynamic effects on aircraft design loads: The landing impact case

    NASA Astrophysics Data System (ADS)

    Bronstein, Michael; Feldman, Esther; Vescovini, Riccardo; Bisagni, Chiara

    2015-10-01

    This paper addresses the potential benefits due to a fully dynamic approach to determine the design loads of a mid-size business jet. The study is conducted by considering the fuselage midsection of the DAEDALOS aircraft model with landing impact conditions. The comparison is presented in terms of stress levels between the novel dynamic approach and the standard design practice based on the use of equivalent static loads. The results illustrate that a slight reduction of the load levels can be achieved, but careful modeling of the damping level is needed. Guidelines for an improved load definition are discussed, and suggestions for future research activities are provided.

  14. Variables during swing associated with decreased impact peak and loading rate in running.

    PubMed

    Schmitz, Anne; Pohl, Michael B; Woods, Kaitlin; Noehren, Brian

    2014-01-03

    When the foot impacts the ground in running, large forces and loading rates can arise that may contribute to the development of overuse injuries. Investigating which biomechanical factors contribute to these impact loads and loading rates in running could assist clinicians in developing strategies to reduce these loads. Therefore, the goals of our work were to determine variables that predict the magnitude of the impact peak and loading rate during running, as well as to investigate how modulation of knee and hip muscle activity affects these variables. Instrumented gait analysis was conducted on 48 healthy subjects running at 3.3m/s on a treadmill. The top four predictors of loading rate and impact peak were determined using a stepwise multiple linear regression model. Forward dynamics was performed using a whole body musculoskeletal model to determine how increased muscle activity of the knee flexors, knee extensors, hip flexors, and hip extensors during swing altered the predictors of loading rate and impact peak. A smaller impact peak was associated with a larger downward acceleration of the foot, a higher positioned foot, and a decreased downward velocity of the shank at mid-swing while a lower loading rate was associated with a higher positioned thigh at mid-swing. Our results suggest that an alternative to forefoot striking may be increased hip flexor activity during swing to alter these mid-swing kinematics and ultimately decrease the leg's velocity at landing. The decreased velocity would decrease the downward momentum of the leg and hence require a smaller force at impact. © 2013 Published by Elsevier Ltd.

  15. Behavior of Compression-Loaded Composite Panels with Stringer Terminations and Impact Damage

    NASA Technical Reports Server (NTRS)

    Jegley, Dawn C.

    1998-01-01

    The results of an analytical and experimental study of graphite-epoxy stiffened panels with impact-damaged stringer terminations are presented. Five stitched graphite-epoxy panels with stiffeners with a gradual reduction in either thickness or height were examined. Panels were analyzed using finite element analysis and tested by loading them in axial compression to a predetermined load. The panels were then subjected to impact damage and loaded to failure. Axial midplane strains, surface strains, interlaminar strains and failure results are discussed.

  16. Normal dynamic deformation characteristics of non-consecutive jointed rock masses under impact loads

    NASA Astrophysics Data System (ADS)

    Zeng, Sheng; Jiang, Bowei; Sun, Bing

    2017-08-01

    In order to study deformation characteristics of non-consecutive single jointed rock masses under impact loads, we used the cement mortar materials to make simulative jointed rock mass samples, and tested the samples under impact loads by the drop hammer. Through analyzing the time-history signal of the force and the displacement, first we find that the dynamic compression displacement of the jointed rock mass is significantly larger than that of the intact jointless rock mass, the compression displacement is positively correlated with the joint length and the impact height. Secondly, the vertical compressive displacement of the jointed rock mass is mainly due to the closure of opening joints under small impact loads. Finally, the peak intensity of the intact rock mass is larger than that of the non-consecutive jointed rock mass and negatively correlated with the joint length under the same impact energy.

  17. Response of DP 600 products to dynamic impact loads

    NASA Astrophysics Data System (ADS)

    Clark, Deidra Darcell

    The objective of this study was to compare the microstructural response of various DP 600 products subjected to low velocity, dynamic impact tests, typically encountered in a car crash. Since the response of steel is sensitive to its microstructure as controlled by the alloying elements, phase content, and processing; various DP 600 products may respond differently to crashes. The microstructure before and after dynamic impact deformation at 5 and 10 mph was characterized with regards to grain size, morphology, and phase content among vendors A, B, and C to evaluate efficiency in absorbing energy mechanisms during a crash simulated by dynamic impact testing in a drop tower.

  18. Economic impact of total solids loading on enzymatic hydrolysis of dilute acid pretreated corn stover.

    PubMed

    Humbird, David; Mohagheghi, Ali; Dowe, Nancy; Schell, Daniel J

    2010-01-01

    In process integration studies of the biomass-to-ethanol conversion process, it is necessary to understand how cellulose conversion yields vary as a function of solids and enzyme loading and other key operating variables. The impact of solids loading on enzymatic cellulose hydrolysis of dilute acid pretreated corn stover slurry was determined using an experimental response surface design methodology. From the experimental work, an empirical correlation was obtained that expresses monomeric glucose yield from enzymatic cellulose hydrolysis as a function of solids loading, enzyme loading, and temperature. This correlation was used in a technoeconomic model to study the impact of solids loading on ethanol production economics. The empirical correlation was used to provide a more realistic assessment of process cost by accounting for changes in cellulose conversion yields at different solids and enzyme loadings as well as enzyme cost. As long as enzymatic cellulose conversion drops off at higher total solids loading (due to end-product inhibition or other factors), there is an optimum value for the total solids loading that minimizes the ethanol production cost. The optimum total solids loading shifts to higher values as enzyme cost decreases. © 2010 American Institute of Chemical Engineers

  19. Development of a Spring-Loaded Impact Device to Deliver Injurious Mechanical Impacts to the Articular Cartilage Surface

    PubMed Central

    Alexander, Peter G.; Song, Yingjie; Taboas, Juan M.; Chen, Faye H.; Melvin, Gary M.; Manner, Paul A.

    2013-01-01

    Objective: Traumatic impacts on the articular joint surface in vitro are known to lead to degeneration of the cartilage. The main objective of this study was to develop a spring-loaded impact device that can be used to deliver traumatic impacts of consistent magnitude and rate and to find whether impacts cause catabolic activities in articular cartilage consistent with other previously reported impact models and correlated with the development of osteoarthritic lesions. In developing the spring-loaded impactor, the operating hypothesis is that a single supraphysiologic impact to articular cartilage in vitro can affect cartilage integrity, cell viability, sulfated glycosaminoglycan and inflammatory mediator release in a dose-dependent manner. Design: Impacts of increasing force are delivered to adult bovine articular cartilage explants in confined compression. Impact parameters are correlated with tissue damage, cell viability, matrix and inflammatory mediator release, and gene expression 24 hours postimpact. Results: Nitric oxide release is first detected after 7.7 MPa impacts, whereas cell death, glycosaminoglycan release, and prostaglandin E2 release are first detected at 17 MPa. Catabolic markers increase linearly to maximal levels after ≥36 MPa impacts. Conclusions: A single supraphysiologic impact negatively affects cartilage integrity, cell viability, and GAG release in a dose-dependent manner. Our findings showed that 7 to 17 MPa impacts can induce cell death and catabolism without compromising the articular surface, whereas a 17 MPa impact is sufficient to induce increases in most common catabolic markers of osteoarthritic degeneration. PMID:26069650

  20. Use of body armor protection with fighting load impacts soldier performance and kinematics.

    PubMed

    Loverro, Kari L; Brown, Tyler N; Coyne, Megan E; Schiffman, Jeffrey M

    2015-01-01

    The purpose of this evaluation was to examine how increasing body armor protection with and without a fighting load impacted soldiers' performance and mobility. Thirteen male soldiers performed one performance (repeated 30-m rushing) and three mobility tasks (walk, walk over and walk under) with three different body armor configurations and an anterior fighting load. Increasing body armor protection, decreased soldier performance, as individual and total 30-m rush times were significantly longer with greater protection. While increasing body armor protection had no impact on mobility, i.e. significant effect on trunk and lower limb biomechanics, during the walk and walk over tasks, greater protection did significantly decrease maximum trunk flexion during the walk under task. Adding fighting load may negatively impact soldier mobility, as greater maximum trunk extension was evident during the walk and walk over tasks, and decreased maximum trunk flexion exhibited during the walk under task with the fighting load.

  1. Hydrodynamic Impact-Load Alleviation with a Penetrating Hydro-Ski

    NASA Technical Reports Server (NTRS)

    Edge, Philip M., Jr.

    1959-01-01

    A penetrating hydro-ski was mounted below a model tested previously in the study reported in NACA Technical Note 4401, and a series of impacts were made in the Langley impact basin to determine load alleviation with this type of hydro-ski. The hydro-ski was designed to penetrate through seaway irregularities with a minimum of drag and with small impact loads. The penetrating hydro-ski was small (beam-loading coefficient of 111) and of a streamline shape with the bottom designed for flush retraction into the main model. A series of impacts at fixed trim angles of 8, 16, and 30 deg were made in smooth water and at a fixed trim angle of 8 deg in rough water. The loads and motions of the model were recorded, and photographic observations of the flow and cavities generated in the water by the penetrating hydro-ski were made. The data are presented and the maximum impact loads and maximum drafts of the model with the penetrating hydro-ski are compared with those of the model obtained without the penetrating hydro-ski. Maximum load reductions of 30 to 70 percent in smooth water and of 50 to 80 percent in rough water are indicated. Cavity and flow generation by the penetrating hydro-ski are discussed, and it is indicated that the penetrating hydro-ski moved smoothly through the water and generated deep cavities which are shown by stereophotographs.

  2. Dynamic Response of Soldered Electronic Components under Impact Loading

    DTIC Science & Technology

    2011-12-01

    2   2.   Varying Strain Rates and Solder Joint Failure .................................3   3.   Drop Impact Analysis on Sn - Ag -Cu...absence of significant internal grain rotation, and that it consistent at all strain-rates. 4 3. Drop Impact Analysis on Sn - Ag -Cu Solder Joints...Pang and Che [4] discuss the complexities of drop test analysis and the dangers of over simplifying Sn - Ag -Cu solder joint deformation response. Solder

  3. Projectiles Impact Assessment of Aircraft Wing Structures with Real Dynamic Load

    NASA Astrophysics Data System (ADS)

    Han, Lu; Han, Qing; Wang, Changlin

    2015-07-01

    This paper presents an analysis to achieve the impact damage of the wing structure under real dynamic load. MPCCI tools are utilized to convert wing aerodynamic load into structural Finite Element Method (FEM) node load. The ANSYS/LS-DYNA code is also used to simulate the dynamic loading effects of the wing structure hit by several projectiles, including both active damage mechanism and common damage mechanism. In addition, structural node force on the leading edge and the midline is compared to the aerodynamic load separately. Furthermore, the statistical analysis of the penetrating size and the stress concentration around the damage holes indicates that under the same load situation, the structural damage efficiency of active damage mechanism is significantly higher than the one of common damage mechanism.

  4. Beam diagnostics at high-intensity storage rings

    SciTech Connect

    Plum, M.

    1993-11-01

    Beam diagnostics at high-intensity facilities feature their own special set of problems and characteristics. Issues peculiar to high-intensity storage rings include beam loss, beam halos, extraction efficiency, beam in the gap, clearing electrodes, and beam-profile measurement. The Los Alamos Proton Storage Ring (PSR) is a nice example of a high-intensity storage ring. The author discusses in some detail three diagnostic systems currently in use at the PSR: the beam-loss-monitor system, the electron-clearing system, and the beam-in-the-gap monitor. Much of the discussion is inspired by the problems that were encountered and the useful things learned while commissioning and developing the PSR. Another inspiration is the work on the next-generation neutron-spallation source, also known as the National Center for Neutron Research (NCNR).

  5. Beam diagnostics at high-intensity storage rings

    SciTech Connect

    Plum, M. )

    1994-10-10

    Beam diagnostics at high-intensity facilities feature their own special set of problems and characteristics, issues peculiar to high-intensity storage rings include beam loss, beam halos, extraction efficiency, beam in the gap, clearing electrodes, and beam-profile measurement. The Los Alamos Proton Storage Ring (PSR) is a nice example of a high-intensity storage ring. I will discuss in some detail three diagnostic systems currently in use at the PSR: the beam-loss-monitor system, the electron-clearing system, and the beam-in-the-gap monitor. Much of our discussion is inspired by the problems we have encountered and the useful things we have learned while commissioning and developing the PSR. Another inspiration is our work on the next-generation neutron-spallation source, also known as the National Center for Neutron Research (NCNR).

  6. High-intensity aerobic interval exercise in chronic heart failure.

    PubMed

    Meyer, Philippe; Gayda, Mathieu; Juneau, Martin; Nigam, Anil

    2013-06-01

    Aerobic exercise training is strongly recommended in patients with heart failure (HF) and reduced left ventricular ejection fraction (LVEF) to improve symptoms and quality of life. Moderate-intensity aerobic continuous exercise (MICE) is the best established training modality in HF patients. For about a decade, however, another training modality, high-intensity aerobic interval exercise (HIIE), has aroused considerable interest in cardiac rehabilitation. Originally used by athletes, HIIE consists of repeated bouts of high-intensity exercise interspersed with recovery periods. The rationale for its use is to increase exercise time spent in high-intensity zones, thereby increasing the training stimulus. Several studies have demonstrated that HIIE is more effective than MICE, notably for improving exercise capacity in patients with HF. The aim of the present review is to describe the general principles of HIIE prescription, the acute physiological effects, the longer-term training effects, and finally the future perspectives of HIIE in patients with HF.

  7. Assessing the impact of long-term cultivation on runoff, pollutant load, and crop yields

    USDA-ARS?s Scientific Manuscript database

    Over the past century, agriculture had detrimental impacts on soil and water quality revealed by increased surface runoff and non-point source pollution. In this study, we estimated the impact of long-term agriculture on surface runoff, sediment yield, atrazine load, and crop yields. Soil samples we...

  8. The impact of cognitive load on operatic singers' timing performance.

    PubMed

    Çorlu, Muzaffer; Maes, Pieter-Jan; Muller, Chris; Kochman, Katty; Leman, Marc

    2015-01-01

    In the present paper, we report the results of an empirical study on the effects of cognitive load on operatic singing. The main aim of the study was to investigate to what extent a working memory task affected the timing of operatic singers' performance. Thereby, we focused on singers' tendency to speed up, or slow down their performance of musical phrases and pauses. Twelve professional operatic singers were asked to perform an operatic aria three times; once without an additional working memory task, once with a concurrent working memory task (counting shapes on a computer screen), and once with a relatively more difficult working memory task (more shapes to be counted appearing one after another). The results show that, in general, singers speeded up their performance under heightened cognitive load. Interestingly, this effect was more pronounced in pauses-more in particular longer pauses-compared to musical phrases. We discuss the role of sensorimotor control and feedback processes in musical timing to explain these findings.

  9. The impact of cognitive load on operatic singers' timing performance

    PubMed Central

    Çorlu, Muzaffer; Maes, Pieter-Jan; Muller, Chris; Kochman, Katty; Leman, Marc

    2015-01-01

    In the present paper, we report the results of an empirical study on the effects of cognitive load on operatic singing. The main aim of the study was to investigate to what extent a working memory task affected the timing of operatic singers' performance. Thereby, we focused on singers' tendency to speed up, or slow down their performance of musical phrases and pauses. Twelve professional operatic singers were asked to perform an operatic aria three times; once without an additional working memory task, once with a concurrent working memory task (counting shapes on a computer screen), and once with a relatively more difficult working memory task (more shapes to be counted appearing one after another). The results show that, in general, singers speeded up their performance under heightened cognitive load. Interestingly, this effect was more pronounced in pauses—more in particular longer pauses—compared to musical phrases. We discuss the role of sensorimotor control and feedback processes in musical timing to explain these findings. PMID:25954218

  10. Analysis of high intensity activity in Premier League soccer.

    PubMed

    Di Salvo, V; Gregson, W; Atkinson, G; Tordoff, P; Drust, B

    2009-03-01

    The aim of the present investigation was to provide a detailed analysis of the high intensity running activity completed by elite soccer players during match-play. A further aim of the study was to evaluate the importance of high intensity running activity to overall team success. Observations on individual match performance measures were undertaken on 563 outfield players (median of 8 games per player; range=1-57) competing in the English Premier League from 2003/2004 to 2005/2006 using a computerised tracking system (Prozone, Leeds, England). High intensity activities selected for analysis included total high intensity running distance (THIR), total sprint distance (TSD) and the number and type of sprints undertaken. Total high intensity running distance in possession and without possession of the ball was also analysed. The THIR was dependant upon playing position with wide midfield (1,049+/-106 m) and central defenders (681+/-128 m) completing the highest and lowest distance respectively (p<0.001). High intensity activity was also related to team success with teams finishing in the bottom five (919+/-128 m) and middle ten (917+/-143 m) league positions completing significantly more THIR compared with teams in the top five (885+/-113 m) (p=0.003). The THIR and TSD also significantly declined during the 2nd half with the greatest decrements observed in wide midfield and attacking players (p<0.05). Both positional differences in high intensity activity and the observed change in activity throughout the game were also influenced by team success (p<0.05). The results of the present study indicate that high intensity activity in elite soccer match-play is influenced by both playing position and previous activity in the game. These activity patterns are also dependant upon success of the team. This may indicate that overall technical and tactical effectiveness of the team rather than high levels of physical performance per se are more important in determining success

  11. On the high intensity aspects of AGS Booster proton operation

    SciTech Connect

    Reece, R.K.; Ahrens, L.A.; Bleser, E.J.; Brennan, J.M.; Gardner, C.; Glenn, J.W.; Roser, T.; Shoji, Y.; van Asselt, W.; Weng, W.T.

    1993-06-01

    Observations of high intensity effects on the proton performance of the AGS Booster are presented, including present operational limits and correction methods. The transverse emittances, optimum tune working points, damping of coherent transverse oscillations and correction of stopband resonances through third-order are discussed in addition to the observed tune spread due to space charge forces. The initial longitudinal phase space distribution, capture and acceleration parameters and measurements are also given. Operational tools and strategies relevant to the high intensity setup are mentioned.

  12. On the high intensity aspects of AGS Booster proton operation

    SciTech Connect

    Reece, R.K.; Ahrens, L.A.; Bleser, E.J.; Brennan, J.M.; Gardner, C.; Glenn, J.W.; Roser, T.; Shoji, Y.; van Asselt, W.; Weng, W.T.

    1993-01-01

    Observations of high intensity effects on the proton performance of the AGS Booster are presented, including present operational limits and correction methods. The transverse emittances, optimum tune working points, damping of coherent transverse oscillations and correction of stopband resonances through third-order are discussed in addition to the observed tune spread due to space charge forces. The initial longitudinal phase space distribution, capture and acceleration parameters and measurements are also given. Operational tools and strategies relevant to the high intensity setup are mentioned.

  13. High-intensity subpicosecond vacuum ultraviolet laser system

    NASA Astrophysics Data System (ADS)

    Kubodera, Shoichi; Kaku, Masanori; Taniguchi, Yuta; Katto, Masahito; Yokotani, Atsushi; Miyanaga, Noriaki; Mima, Kunioki

    2008-02-01

    We have been developing an ultrashort-pulse high-intensity vacuum ultraviolet (VUV) laser. Ultrashort VUV pulses at 126 nm have been produced in rare-gases by nonlinear wavelength conversion of an infrared Ti:sapphire laser at 882 nm. This pulse will be amplified inside an Ar II* amplifier excited by optical-field-induced ionization electrons. The amplification characteristics of the Ar II* amplifier has been improved by plasma channeling induced by a high-intensity plasma-initiating laser.

  14. Axion-like-particle search with high-intensity lasers

    NASA Astrophysics Data System (ADS)

    Döbrich, Babette; Gies, Holger

    2010-10-01

    We study ALP -photon-conversion within strong inhomogeneous electromagnetic fields as provided by contemporary high-intensity laser systems. We observe that probe photons traversing the focal spot of a superposition of Gaussian beams of a single high-intensity laser at fundamental and frequency-doubled mode can experience a frequency shift due to their intermittent propagation as axion-like-particles. This process is strongly peaked for resonant masses on the order of the involved laser frequencies. Purely laser-based experiments in optical setups are sensitive to ALPs in the eV mass range and can thus complement ALP searches at dipole magnets.

  15. A Study of the Use of Contact Loading to Simulate Low Velocity Impact

    NASA Technical Reports Server (NTRS)

    Highsmith, Alton L.

    1997-01-01

    Although numerous studies on the impact response of laminated composites have been conducted, there is as yet no agreement within the composites community on what parameter or parameters are adequate for quantifying the severity of an impact event. One of the more interesting approaches that has been proposed uses the maximum contact force during impact to "quantify" the severity of the impact event, provided that the impact velocity is sufficiently low. A significant advantage of this approach, should it prove to be reliable, is that quasi-static contact loading could be used to simulate low velocity impact. In principle, a single specimen, loaded quasi-statically to successively increasing contact loads could be used to map the entire spectrum of damage as a function of maximum contact force. The present study had as its objective assessing whether or not the maximum contact force during impact is a suitable parameter for characterizing an impact. The response of [+/-60/0(sub 4)/+/-60/0(sub 2)](sub s) laminates fabricated from Fiberite T300/934 graphite epoxy and subjected to quasi-static contact loading and to low velocity impact was studied. Three quasi-static contact load levels - 525 lb., 600 lb., and 675 lb. - were selected. Three impact energy levels - 1.14 ft.-lb., 2.0 ft.-lb., and 2.60 ft.-lb. - were chosen in an effort to produce impact events in which the maximum contact forces during the impact events were 525 lb., 600 lb., and 625 lb., respectively. Damage development was documented using dye-penetrant enhanced x-ray radiography. A digital image processing technique was used to obtain quantitative information about the damage zone. Although it was intended that the impact load levels produce maximum contact forces equal to those used in the quasi-static contact experiments, larger contact forces were developed during impact loading. In spite of this, the damage zones developed in impacted specimens were smaller than the damage zones developed in

  16. Experimental and Numerical Investigations of Textile Hybrid Composites Subjected to Low Velocity Impact Loadings

    PubMed Central

    Chandekar, Gautam S.; Kelkar, Ajit D.

    2014-01-01

    In the present study experimental and numerical investigations were carried out to predict the low velocity impact response of four symmetric configurations: 10 ply E Glass, 10 ply AS4 Carbon, and two Hybrid combinations with 1 and 2 outer plies of E Glass and 8 and 6 inner plies of Carbon. All numerical investigations were performed using commercial finite element software, LS-DYNA. The test coupons were manufactured using the low cost Heated Vacuum Assisted Resin Transfer Molding (H-VARTM©) technique. Low velocity impact testing was carried out using an Instron Dynatup 8250 impact testing machine. Standard 6 × 6 Boeing fixture was used for all impact experiments. Impact experiments were performed over progressive damage, that is, from incipient damage till complete failure of the laminate in six successive impact energy levels for each configuration. The simulation results for the impact loading were compared with the experimental results. For both nonhybrid configurations, it was observed that the simulated results were in good agreement with the experimental results, whereas, for hybrid configurations, the simulated impact response was softer than the experimental response. Maximum impact load carrying capacity was also compared for all four configurations based on their areal density. It was observed that Hybrid262 configuration has superior impact load to areal density ratio. PMID:24719573

  17. Experimental and numerical investigations of textile hybrid composites subjected to low velocity impact loadings.

    PubMed

    Chandekar, Gautam S; Kelkar, Ajit D

    2014-01-01

    In the present study experimental and numerical investigations were carried out to predict the low velocity impact response of four symmetric configurations: 10 ply E Glass, 10 ply AS4 Carbon, and two Hybrid combinations with 1 and 2 outer plies of E Glass and 8 and 6 inner plies of Carbon. All numerical investigations were performed using commercial finite element software, LS-DYNA. The test coupons were manufactured using the low cost Heated Vacuum Assisted Resin Transfer Molding (H-VARTM©) technique. Low velocity impact testing was carried out using an Instron Dynatup 8250 impact testing machine. Standard 6 × 6 Boeing fixture was used for all impact experiments. Impact experiments were performed over progressive damage, that is, from incipient damage till complete failure of the laminate in six successive impact energy levels for each configuration. The simulation results for the impact loading were compared with the experimental results. For both nonhybrid configurations, it was observed that the simulated results were in good agreement with the experimental results, whereas, for hybrid configurations, the simulated impact response was softer than the experimental response. Maximum impact load carrying capacity was also compared for all four configurations based on their areal density. It was observed that Hybrid262 configuration has superior impact load to areal density ratio.

  18. Impact evaluation of conducted UWB transients on loads in power-line networks

    NASA Astrophysics Data System (ADS)

    Li, Bing; Månsson, Daniel

    2017-09-01

    Nowadays, faced with the ever-increasing dependence on diverse electronic devices and systems, the proliferation of potential electromagnetic interference (EMI) becomes a critical threat for reliable operation. A typical issue is the electronics working reliably in power-line networks when exposed to electromagnetic environment. In this paper, we consider a conducted ultra-wideband (UWB) disturbance, as an example of intentional electromagnetic interference (IEMI) source, and perform the impact evaluation at the loads in a network. With the aid of fast Fourier transform (FFT), the UWB transient is characterized in the frequency domain. Based on a modified Baum-Liu-Tesche (BLT) method, the EMI received at the loads, with complex impedance, is computed. Through inverse FFT (IFFT), we obtain time-domain responses of the loads. To evaluate the impact on loads, we employ five common, but important quantifiers, i.e., time-domain peak, total signal energy, peak signal power, peak time rate of change and peak time integral of the pulse. Moreover, to perform a comprehensive analysis, we also investigate the effects of the attributes (capacitive, resistive, or inductive) of other loads connected to the network, the rise time and pulse width of the UWB transient, and the lengths of power lines. It is seen that, for the loads distributed in a network, the impact evaluation of IEMI should be based on the characteristics of the IEMI source, and the network features, such as load impedances, layout, and characteristics of cables.

  19. SRB/FWC water impact: Flexible body loads test

    NASA Technical Reports Server (NTRS)

    1984-01-01

    The modeling of the cavity collapse pressure loading is discussed. There are excellent high speed color films of the quarter scale model during cavity collapse. In these films, it is possible to see a very clearly defined pressure wave front propagating circumferentially around the vehicle that seems to be associated at least on the lee side with an abrupt rise in pressure at each pressure transducer. By using a motion analyzer and stepping through the films, the location of this wave front is tracted at a number of time intervals for drops 17 through 21. The entry conditions and average wave front velocity are shown. Mathematical formulae aid in the reconstruction of the spatial distribution of the pressure.

  20. Mechanical Characterization of the Human Lumbar Intervertebral Disc Subjected to Impact Loading Conditions

    NASA Astrophysics Data System (ADS)

    Jamison, David, IV

    Low back pain is a large and costly problem in the United States. Several working populations, such as miners, construction workers, forklift operators, and military personnel, have an increased risk and prevalence of low back pain compared to the general population. This is due to exposure to repeated, transient impact shocks, particularly while operating vehicles or other machinery. These shocks typically do not cause acute injury, but rather lead to pain and injury over time. The major focus in low back pain is often the intervertebral disc, due to its role as the major primary load-bearing component along the spinal column. The formation of a reliable standard for human lumbar disc exposure to repeated transient shock could potentially reduce injury risk for these working populations. The objective of this project, therefore, is to characterize the mechanical response of the lumbar intervertebral disc subjected to sub-traumatic impact loading conditions using both cadaveric and computational models, and to investigate the possible implications of this type of loading environment for low back pain. Axial, compressive impact loading events on Naval high speed boats were simulated in the laboratory and applied to human cadaveric specimen. Disc stiffness was higher and hysteresis was lower than quasi-static loading conditions. This indicates a shift in mechanical response when the disc is under impact loads and this behavior could be contributing to long-term back pain. Interstitial fluid loss and disc height changes were shown to affect disc impact mechanics in a creep study. Neutral zone increased, while energy dissipation and low-strain region stiffness decreased. This suggests that the disc has greater clinical instability during impact loading with progressive creep and fluid loss, indicating that time of day should be considered for working populations subjected to impact loads. A finite element model was developed and validated against cadaver specimen

  1. Damage Characteristics and Residual Strength of Composite Sandwich Panels Impacted with and Without Compression Loading

    NASA Technical Reports Server (NTRS)

    McGowan, David M.; Ambur, Damodar R.

    1998-01-01

    The results of an experimental study of the impact damage characteristics and residual strength of composite sandwich panels impacted with and without a compression loading are presented. Results of impact damage screening tests conducted to identify the impact-energy levels at which damage initiates and at which barely visible impact damage occurs in the impacted facesheet are discussed. Parametric effects studied in these tests include the impactor diameter, dropped-weight versus airgun-launched impactors, and the effect of the location of the impact site with respect to the panel boundaries. Residual strength results of panels tested in compression after impact are presented and compared with results of panels that are subjected to a compressive preload prior to being impacted.

  2. Evaluation of a Compression-Loaded-Stitched-Multi-Bay Fuselage Panel With Barely Visible Impact Damage

    NASA Technical Reports Server (NTRS)

    Baker, Donald J.; Li, Ji-An

    2005-01-01

    The experimental results from a stitched VaRTM carbon-epoxy composite panel tested under uni-axial compression loading are presented along with nonlinear finite element analysis prediction of the response. The curved panel is divided by frames and stringers into six bays with a column of three bays along the compressive loading direction. The frames are supported at the frame ends to resist out-of-plane translation. Back-to-back strain gages are used to record the strain and displacement transducers were used to record the out-of-plane displacements. In addition a full-field-displacement measurement technique that utilizes a camera-based-stereo-vision system was used to record the displacements. The panel was loaded to 1.5 times the predicted initial buckling load (1st bay buckling load, P(sub er) from the nonlinear finite element analysis and then was removed from the test machine for impact testing. After impacting with 20 ft-lbs of energy using a spherical impactor to produce barely visible damage the panel was loaded in compression until failure. The buckling load of the first bay to buckle was 97% of the buckling load before impact. The stitching constrained the impact damage from growing during the loading to failure. Impact damage had very little overall effect on panel stiffness. Panel stiffness measured by the full-field-displacement technique indicated a 13% loss in stiffness after impact. The panel failed at 1.64 times the first panel buckling load. The barely visible impact damage did not grow noticeably as the panel failed by global instability due to stringer-web terminations at the frame locations. The predictions from the nonlinear analysis of the finite element modeling of the entire specimen were very effective in the capture of the initial buckling and global behavior of the panel. In addition, the prediction highlighted the weakness of the panel under compression due to stringer web terminations. Both the test results and the nonlinear

  3. Tolerable Beam Loss at High-Intensity Machines

    SciTech Connect

    Oleg E. Krivosheev, Nikolai V. Mokhov

    2000-08-28

    Tolerable beam losses are estimated for high-intensity ring accelerators with proton energy of 3 to 16 GeV. Dependence on beam energy, lattice and magnet geometry is studied via full Monte Carlo MARS14 simulations in lattice elements, shielding, tunnel and surrounding dirt with realistic geometry, materials and magnetic fields.

  4. The classical theory of dispersion of high-intensity light

    SciTech Connect

    Kozlov, S.A.

    1995-08-01

    The dependence of the nonlinear refractive index of an optical medium on the optical wave frequency in the classical theory of dispersion of high-intensity light is shown to have the same form as in the quantum theory if a structural unit of substance in the Lorentz model is considered as two parametrically coupled nonlinear oscillators rather than one oscillator. 13 refs.

  5. Drift tube suspension for high intensity linear accelerators

    DOEpatents

    Liska, D.J.; Schamaun, R.G.; Clark, D.C.; Potter, R.C.; Frank, J.A.

    1980-03-11

    The disclosure relates to a drift tube suspension for high intensity linear accelerators. The system comprises a series of box-sections girders independently adjustably mounted on a linear accelerator. A plurality of drift tube holding stems are individually adjustably mounted on each girder.

  6. Drift tube suspension for high intensity linear accelerators

    DOEpatents

    Liska, Donald J.; Schamaun, Roger G.; Clark, Donald C.; Potter, R. Christopher; Frank, Joseph A.

    1982-01-01

    The disclosure relates to a drift tube suspension for high intensity linear accelerators. The system comprises a series of box-sections girders independently adjustably mounted on a linear accelerator. A plurality of drift tube holding stems are individually adjustably mounted on each girder.

  7. High-power, high-intensity laser propagation and interactions

    SciTech Connect

    Sprangle, Phillip; Hafizi, Bahman

    2014-05-15

    This paper presents overviews of a number of processes and applications associated with high-power, high-intensity lasers, and their interactions. These processes and applications include: free electron lasers, backward Raman amplification, atmospheric propagation of laser pulses, laser driven acceleration, atmospheric lasing, and remote detection of radioactivity. The interrelated physical mechanisms in the various processes are discussed.

  8. [Treatment of uterine fibroids using high-intensity ultrasound].

    PubMed

    Pessarrodona, Antoni; Isern, Jordi; Rodríguez, Jordi; Vallejo, Elena; Cassado, Jordi

    2013-07-01

    High-intensity ultrasound surgery is being actively introduced as an alternative treatment to conventional surgery for uterine fibroids. Numerous studies have shown that high-intensity ultrasound surgery is a safe and effective treatment, with fewer side effects than fibroidectomy and hysterectomy, and is cost-effective. It is now possible to offer this alternative therapy to patients with symptomatic uterine fibroids. We describe the technical basis of ultrasound surgery, the pretherapy selection of patients, the limiting factors and the risks of high-intensity ultrasound therapy. We describe our unit's clinical experience with 319 patients treated in an outpatient regimen, which resulted in a high rate of success (81%) and an acceptable rate of mild complications, as well as a virtually immediate return to daily activities. We comment on the follow-up of pregnancies that occurred after treatment with high-intensity focused ultrasound (HIFU) with no side effects attributable to the therapy. Copyright © 2013 Elsevier España, S.L. All rights reserved.

  9. Reuse Recycler: High Intensity Proton Stacking at Fermilab

    SciTech Connect

    Adamson, P.

    2016-07-17

    After a successful career as an antiproton storage and cooling ring, Recycler has been converted to a high intensity proton stacker for the Main Injector. We discuss the commissioning and operation of the Recycler in this new role, and the progress towards the 700 kW design goal.

  10. Clinical applications of high-intensity focused ultrasound.

    PubMed

    She, W H; Cheung, T T; Jenkins, C R; Irwin, M G

    2016-08-01

    Ultrasound has been developed for therapeutic use in addition to its diagnostic ability. The use of focused ultrasound energy can offer a non-invasive method for tissue ablation, and can therefore be used to treat various solid tumours. High-intensity focused ultrasound is being increasingly used in the treatment of both primary and metastatic tumours as these can be precisely located for ablation. It has been shown to be particularly useful in the treatment of uterine fibroids, and various solid tumours including those of the pancreas and liver. High-intensity focused ultrasound is a valid treatment option for liver tumours in patients with significant medical co-morbidity who are at high risk for surgery or who have relatively poor liver function that may preclude hepatectomy. It has also been used as a form of bridging therapy while patients awaiting cadaveric donor liver transplantation. In this article, we outline the principles of high-intensity focused ultrasound and its clinical applications, including the management protocol development in the treatment of hepatocellular carcinoma in Hong Kong by performing a search on MEDLINE (OVID), EMBASE, and PubMed. The search of these databases ranged from the date of their establishment until December 2015. The search terms used were: high-intensity focused ultrasound, ultrasound, magnetic resonance imaging, liver tumour, hepatocellular carcinoma, pancreas, renal cell carcinoma, prostate cancer, breast cancer, fibroids, bone tumour, atrial fibrillation, glaucoma, Parkinson's disease, essential tremor, and neuropathic pain.

  11. Critical design issues of high intensity proton linacs

    SciTech Connect

    Lawrence, G.P.

    1994-08-01

    Medium-energy proton linear accelerators are being studied as drivers for spallation applications requiring large amounts of beam powder. Important design factors for such high-intensity linacs are reviewed, and issues and concerns specific to this unprecedented power regime are discussed.

  12. Nonlinear behavior in high-intensity discharge lamps

    NASA Astrophysics Data System (ADS)

    Baumann, Bernd; Schwieger, Joerg; Wolff, Marcus; Manders, Freddy; Suijker, Jos

    2016-06-01

    The light flicker problem of high intensity discharge lamps is studied numerically and experimentally. It is shown that in some respects the systems behave very similar to the forced Duffing oscillator with a softening spring. In particular, the jump phenomenon and hysteresis are observed in the simulations and in the experiments.

  13. The Worker Three Months after High Intensity Training.

    ERIC Educational Resources Information Center

    Nadeau, Richard P.

    A study of the long-range effects of high-intensity training (HIT) was conducted in 13 different programs in eight companies in Baltimore. A total of 99 HIT trainees were interviewed three months after completing the training. After three months the trainees were examined for higher salaries and higher skill levels. HIT appeared to have a positive…

  14. High-Intensity Interval Training for Improving Postprandial Hyperglycemia

    ERIC Educational Resources Information Center

    Little, Jonathan P.; Francois, Monique E.

    2014-01-01

    High-intensity interval training (HIIT) has garnered attention in recent years as a time-efficient exercise option for improving cardiovascular and metabolic health. New research demonstrates that HIIT may be particularly effective for improving postprandial hyperglycemia in individuals with, or at risk for, type 2 diabetes (T2D). These findings…

  15. High-Intensity Interval Training for Improving Postprandial Hyperglycemia

    ERIC Educational Resources Information Center

    Little, Jonathan P.; Francois, Monique E.

    2014-01-01

    High-intensity interval training (HIIT) has garnered attention in recent years as a time-efficient exercise option for improving cardiovascular and metabolic health. New research demonstrates that HIIT may be particularly effective for improving postprandial hyperglycemia in individuals with, or at risk for, type 2 diabetes (T2D). These findings…

  16. Impacts of groundwater metal loads from bedrock fractures on water quality of a mountain stream.

    PubMed

    Caruso, Brian S; Dawson, Helen E

    2009-06-01

    Acid mine drainage and metal loads from hardrock mines to surface waters is a significant problem in the western USA and many parts of the world. Mines often occur in mountain environments with fractured bedrock aquifers that serve as pathways for metals transport to streams. This study evaluates impacts from current and potential future groundwater metal (Cd, Cu, and Zn) loads from fractures underlying the Gilt Edge Mine, South Dakota, on concentrations in Strawberry Creek using existing flow and water quality data and simple mixing/dilution mass balance models. Results showed that metal loads from bedrock fractures to the creek currently contribute <1% of total loads. Even if background water quality is achieved upstream in Strawberry Creek, fracture metal loads would be <5%. Fracture loads could increase substantially and cause stream water quality standards exceedances once groundwater with elevated metals concentrations in the aquifer matrix migrates to the fractures and discharges to the stream. Potential future metal loads from an upstream fracture would contribute a small proportion of the total load relative to current loads in the stream. Cd has the highest stream concentrations relative to standards. Even if all stream water was treated to remove 90% of the Cd, the standard would still not be achieved. At a fracture farther downstream, the Cd standard can only be met if the upstream water is treated achieving a 90% reduction in Cd concentrations and the median stream flow is maintained.

  17. Assessment of particulate cellulose epoxy composites manufactured by JMFIL under impact load

    NASA Astrophysics Data System (ADS)

    Srinivasababu, Nadendla

    2015-08-01

    Increase in environmental concern towards sustainable development invites the development of new materials which are eco-friendly to satisfy various engineering needs. The present work introduces a new manufacturing method i.e. "Just Mold Fill and Immediate Loading" to prepare epoxy composites reinforced at different contents of particulate cellulose. The fabricated composites specimens are post processed and machined, tested as per ASTM procedures under impact load.

  18. Dynamic Failure of Sandwich Beams With Fluid-Structure Interaction Under Impact Loading

    DTIC Science & Technology

    2010-12-01

    14 Figure 7. Piezo electric load cell...gal) of water to achieve a specimen depth of 50.8 mm (2 in) below the free surface. A ball valve attached to a standard garden hose can drain the...sleeve fitted over the end of the impacting rod. Figure 7. Piezo electric load cell As with Owen’s experiment, data acquisition was carried out

  19. An extravehicular suit impact load attenuation study to improve astronaut bone fracture prediction.

    PubMed

    Sulkowski, Christina M; Gilkey, Kelly M; Lewandowski, Beth E; Samorezov, Sergey; Myers, Jerry G

    2011-04-01

    Understanding the contributions to the risk of bone fracture during spaceflight is essential for mission success. A pressurized extravehicular activity (EVA) suit analogue test bed was developed, impact load attenuation data were obtained, and the load at the hip of an astronaut who falls to the side during an EVA was characterized. Offset (representing the gap between the EVA suit and the astronaut's body), impact load magnitude, and EVA suit operating pressure were factors varied in the study. The attenuation data were incorporated into a probabilistic model of bone fracture risk during spaceflight, replacing the previous load attenuation value that was based on commercial hip protector data. Load attenuation was more dependent on offset than on pressurization or load magnitude, especially at small offset values. Load attenuation factors for offsets between 0.1-1.5 cm were 0.69 +/- 0.15, 0.49 +/- 0.22, and 0.35 +/- 0.18 for mean impact forces of 4827, 6400, and 8467 N, respectively. Load attenuation factors for offsets of 2.8-5.3 cm were 0.93 +/- 0.2, 0.94 +/- 0.1, and 0.84 +/- 0.5 for the same mean impact forces. The mean and 95th percentile bone fracture risk index predictions were each reduced by 65-83%. The mean and 95th percentile bone fracture probability predictions were both reduced approximately 20-50%. The reduction in uncertainty and improved confidence in bone fracture predictions increased the fidelity and credibility of the fracture risk model and its benefit to mission design and in-flight operational decisions.

  20. Wave Shaping and Lateral Spreading of Impact Loads Using Layered Materials and Structures

    NASA Astrophysics Data System (ADS)

    Ding, J. L.; Robbins, J.; Gupta, Y. M.; Wong, M. K.

    1999-06-01

    The overall objective of our work is to explore a new concept for developing resilient armor using high wave speed layers to rapidly spread the loads arising from projectile impacts. Because layered structures involve many additional geometrical and material variables, and because layers affect stress distribution and energy absorption capability of the target, a fundamental issue in determining layering effects is the quantification of load spreading in a consistent manner. We have found that the distribution of dissipative energy density normalized by the averaged total energy density imparted to the substrate appears to be an effective measure for evaluating load spreading and penetration resistance of layered targets. Using this measure in numerical simulations, we have demonstrated the feasibility of the load spreading concept. In addition, we have also investigated numerically the effects of layering geometry, and mechanical properties of the layer and substrate on load spreading. Experimental work is currently underway to evaluate the computational results.

  1. Effects of nonlinear ultrasound propagation on high intensity brain therapy.

    PubMed

    Pinton, Gianmarco; Aubry, Jean-Francois; Fink, Mathias; Tanter, Mickael

    2011-03-01

    As an ultrasound wave propagates nonlinearly, energy is transferred to higher frequencies where it is more strongly attenuated. Compared to soft tissue, the skull has strongly heterogeneous material parameters. The authors characterize with experiments and establish a numerical method that can describe the effects of the skull on the nonlinear components of ultrasonic wave propagation for application to high intensity focused ultrasound (HIFU) therapy in the brain. The impact of nonlinear acoustic propagation on heat deposition and thermal dose delivery is quantified and compared to linear assumptions by coupling an acoustic simulation with a heating model for brain tissue. A degassed dessicated human skull was placed in a water tank and insonified at 1 MPa with 7 mm transducer from a custom array designed for HIFU treatment. Two dimensional scans were performed preceding and following propagation through the skull with a calibrated hydrophone. Data from the scan preceding the skull were used as an input to a three dimensional finite difference time domain (FDTD) simulation that calculates the effects of diffraction, density, attenuation with linear dependence on frequency via relaxation mechanisms, and second order nonlinearity. A measured representation of the skull was used to determine the skull's acoustic properties. The validated acoustic model was used to determine the loss due to nonlinear propagation and then coupled to a finite difference simulation of the bioheat equation for two focal configurations at 3 and 7.5 cm from the skull surface. Prior to propagation through the skull, the second harmonic component was 19 dB lower than the fundamental, and the third harmonic component was 37 dB lower. Following the skull, the second harmonic component was 35 dB lower and the third harmonic was 55 dB lower. The simulation is in agreement with the measurements to within 0.5 dB across the considered frequency range and shows good agreement across the two

  2. A new method for predicting nonlinear structural vibrations induced by ground impact loading

    NASA Astrophysics Data System (ADS)

    Liu, Jun; Zhang, Yu; Yun, Bin

    2012-04-01

    Based on nonlinear theory and field measurements, a hybrid method for modeling the time history of structural vibrations resulting from impact loading in the vicinity of a structure is presented in this paper. The characteristics of the medium present between the impact source and a measured location inside of a structure are depicted by a nonlinear system that can be modeled by a Volterra functional series. The nonlinear system can be identified by the inputs and the corresponding output signals, which can be obtained by performing in situ experiments. Then, the predicted signal induced by a known impact loading at the measured location can be calculated using the identified Volterra functional series. Moreover, the structural vibration under a known impulse train can be controlled by adjusting the delay period according to the predicted results. In addition, the method has been verified by applying it in two practical applications: the cases of impact loading induced by either the impact of a hammer or blasting. The results show that the method features convenient application, high precision and extensive applicability for various types of impact loadings.

  3. The impact of luminance on tonic and phasic pupillary responses to sustained cognitive load.

    PubMed

    Peysakhovich, Vsevolod; Vachon, François; Dehais, Frédéric

    2017-02-01

    Pupillary reactions independent of light conditions have been linked to cognition for a long time. However, the light conditions can impact the cognitive pupillary reaction. Previous studies underlined the impact of luminance on pupillary reaction, but it is still unclear how luminance modulates the sustained and transient components of pupillary reaction - tonic pupil diameter and phasic pupil response. In the present study, we investigated the impact of the luminance on these two components under sustained cognitive load. Fourteen participants performed a novel working memory task combining mathematical computations with a classic n-back task. We studied both tonic pupil diameter and phasic pupil response under low (1-back) and high (2-back) working memory load and two luminance levels (gray and white). We found that the impact of working memory load on the tonic pupil diameter was modulated by the level of luminance, the increase in tonic pupil diameter with the load being larger under lower luminance. In contrast, the smaller phasic pupil response found under high load remained unaffected by luminance. These results showed that luminance impacts the cognitive pupillary reaction - tonic pupil diameter (phasic pupil response) being modulated under sustained (respectively, transient) cognitive load. These findings also support the relationship between the locus-coeruleus system, presumably functioning in two firing modes - tonic and phasic - and the pupil diameter. We suggest that the tonic pupil diameter tracks the tonic activity of the locus-coeruleus while phasic pupil response reflects its phasic activity. Besides, the designed novel cognitive paradigm allows the simultaneous manipulation of sustained and transient components of the cognitive load and is useful for dissociating the effects on the tonic pupil diameter and phasic pupil response.

  4. Manipulation of cognitive load variables and impact on auscultation test performance.

    PubMed

    Chen, Ruth; Grierson, Lawrence; Norman, Geoffrey

    2015-10-01

    Health profession educators have identified auscultation skill as a learning need for health professional students. This article explores the application of cognitive load theory (CLT) to designing cardiac and respiratory auscultation skill instruction for senior-level undergraduate nursing students. Three experiments assessed student auscultation performance following instructional manipulations of the three primary components of cognitive load: intrinsic, extraneous, and germane load. Study 1 evaluated the impact of intrinsic cognitive load by varying the number of diagnoses learned in one instruction session; Study 2 evaluated the impact of extraneous cognitive load by providing students with single or multiple examples of diagnoses during instruction; and Study 3 evaluated the impact of germane cognitive load by employing mixed or blocked sequences of diagnostic examples to students. Each of the three studies presents results that support CLT as explaining the influence of different types of cognitive processing on auscultation skill acquisition. We conclude with a discussion regarding CLT's usefulness as a framework for education and education research in the health professions.

  5. A Methodology to Analyze the Impact of 30-Minute Wind Scheduling on Load-Following Requirements

    SciTech Connect

    Diao, Ruisheng; Makarov, Yuri V.; Samaan, Nader A.; Kujala, Ben

    2014-12-24

    This paper proposes a new and systematic approach to investigating the impact of wind transfer between balancing authorities (BAs) with half-hour scheduling on load following requirements, which was traditionally scheduled on an hourly basis. The analysis is conducted for a few BAs in the Pacific Northwest of the U.S. that are described as source BAs (sending renewables) and sink BAs (receiving renewables). The main hypothesis is that if the source BA could schedule interchange for wind on a half-hourly basis, it would make the schedule follow its net load more closely. The scheduling change in the source BA is matched by adding the corresponding component to the net load in the sink BA. The load-following requirements are calculated as: (a) by the difference between the net load and modified schedule in the source BA, and (b) the difference between modified net load and unchanged hourly schedule in the sink BA. Results are presented as hourly upward and downward load following requirements in the source and sink BA, and compared with the results obtained with all generators scheduled on an hourly basis. Thus, the proposed method can effectively help utilities better understand the impact of 30-minute scheduling and make better business decisions.

  6. Repetitive impact loading causes local plastic deformation in wood

    NASA Astrophysics Data System (ADS)

    Salmi, Ari; Salminen, Lauri I.; Engberg, Birgitta A.; Björkqvist, Tomas; Hæggström, Edward

    2012-01-01

    The relationship between the impactor velocity and the amount of strain localization in a single impact compression of cellular solids is known. However, few studies report on the effects of repeated high frequency compression. We therefore studied the mechanical behavior of Norway spruce, a cellular viscoelastic material, before, during, and after cyclic high frequency, high strain rate, compression. A custom made device applied 5000-20 000 unipolar (constrained compression and free relaxation) fatigue cycles with a 0.75 mm peak-to-peak amplitude at 500 Hz frequency. The consequences of this treatment were quantified by pitch-catch ultrasonic measurements and by dynamic material testing using an encapsulated Split-Hopkinson device that incorporated a high-speed camera. The ultrasonic measurements quantified a stiffness modulus drop and revealed the presence of a fatigued low modulus layer near the impacting surface. Such a localized plastic deformation is not predicted by classical mechanics. We introduce a simple model that explains several changes in the mechanical properties caused by fatiguing. The high speed images indicated pronounced strain localization in the weakest (thinnest walls) parts of the earlywood layers, and revealed strain propagation as a function of time. We present a hypothesis explaining why there is a fatigued layer formed in a piece of wood that has sustained cyclic compression and free relaxation.

  7. The effect of low fluoride concentrations on microdamage accumulation in mouse tibias under impact loading

    NASA Astrophysics Data System (ADS)

    Luo, Qing; Chen, Nan; Zhou, Yan-Heng; Rong, Qi-Guo

    2015-12-01

    Microdamage accumulation in bone is one of the mechanisms for energy dissipation during the fracture process. Changes in the ultrastructure and composition of bone constituents due to aging or diseases could affect microdamage accumulation. Low concentration (1 mM) of sodium fluoride (NaF) has been used in this study to investigate the effect of ultrastructural changes on microdamage accumulation in mouse tibias following free-fall impact loadings. Twenty-two tibias were divided randomly into control and NaF-treated groups. Free-fall impact loading was conducted twice on each tibia to produce microdamage. The elastic modulus of NaF-treated tibias decreased significantly after the impact loadings, while there was no significant difference in the modulus of untreated samples between pre- and post-damage loadings. Microdamage morphology analysis showed that less and shorter microcracks existed in NaF-treated tibias compared with control bones. Meanwhile, more and longer microcracks were observed in tensile regions in untreated samples compared with that in compressive regions, whereas no significant difference was observed between tensile and compressive regions in NaF-treated bones. The results of this study indicate that more energy is required to generate microcracks in NaF-treated bone than in normal bone. A low concentration of fluoride treatment may increase the toughness of bone under impact loading.

  8. The upgraded rf system for the AGS and high intensity proton beams

    SciTech Connect

    Brennan, J.M.

    1995-05-01

    The AGS has been upgraded over the past three years to produce a record beam intensity of 6 {times} 10{sup 13} protons per pulse for the fixed-target physics program. The major elements of the upgrade are: the new 1.5 GeV Booster synchrotron, the main magnet power supply, a high frequency longitudinal dilution cavity, a feedback damper for transverse instabilities, a fast gamma transition jump system, and a new high-power rf system. The new rf system and its role in achieving the high intensity goal are the subjects of this report. The rf system is heavily beam loaded, with 7 Amps of rf current in the beam and a peak power of 0.75 MW delivered to the beam by ten cavities. As an example of the scale of beam loading, at one point in the acceleration cycle the cavities are operated at 1.5 kV/gap; whereas, were it not for the new power amplifiers, the beam-induced voltage on the cavities would be over 25 kV/gap. The upgraded rf system, comprising: new power amplifiers, wide band rf feedback, improved cavities, and new low-level beam control electronics, is described. Results of measurements with beam, which characterize the system`s performance, are presented. A typical high intensity acceleration cycle is described with emphasis on the key challenges of beam loading.

  9. A numerical analysis of empty and foam-filled aluminium conical tubes under oblique impact loading

    NASA Astrophysics Data System (ADS)

    Mat, Fauziah; Ismail, Khairul Azwan; Yaacob, Sazali

    2015-05-01

    In real impact applications, an energy absorber rarely sustains dynamic loading either axial or oblique but a combination of both. Established studies have proved that thin-walled tube is an excellent energy absorber under dynamic loading. Furthermore, the introduction of foam filling successfully enhanced the energy absorption capacity of thin-walled tube. However, the understanding of its response under oblique loading has yet been fully explored. Moreover, emerging in automotive industry has lead to increase interests on lightweight materials such as aluminium alloy. As such, this paper presents the crushing behaviour of empty and foam-filled aluminium alloy (AA6061-T6) conical tubes under oblique impact loading using a validated nonlinear finite element (FE) code, LS-DYNA. The study aims to assess the effect of foam filling on the energy absorption of AA6061-T6 tubes for variations in filler density. In fact, to the best of our knowledge, this study is the first attempt to evaluate a response of empty and foam-filled aluminum conical tube by using an experimentally validated model under oblique dynamic loading conditions. Good correlations between the numerical and experimental results were observed. The study show that initial peak force and the energy absorption increase with increasing filler density under axial and oblique loading. On the other hand, the effect of foam filling (0.534 g/cm3 aluminium foam filler) is less pronounced for the initial peak force under axial impact loading. Furthermore, the initial peak force and dynamic force of empty and foam-filled AA6061-T6 conical tubes decrease as the load angle increases from 0 deg to 20 deg hence reduces the energy absorption capacity.

  10. Failure characteristics of the isolated distal radius in response to dynamic impact loading.

    PubMed

    Burkhart, Timothy A; Andrews, David M; Dunning, Cynthia E

    2012-06-01

    We examined the mechanical response of the distal radius pre-fracture and at fracture under dynamic impact loads. The distal third of eight human cadaveric radii were potted and placed in a custom designed pneumatic impact system. The distal intra-articular surface of the radius rested against a model scaphoid and lunate, simulating 45° of wrist extension. The scaphoid and lunate were attached to a load cell that in turn was attached to an impact plate. Impulsive impacts were applied at increasing energy levels, in 10 J increments, until fracture occurred. Three 45° stacked strain gauge rosettes were affixed along the length of the radius quantifying the bone strains. The mean (SD) fracture energy was 45.5 (16) J. The mean (SD) resultant impact reaction force (IRFr) at failure was 2,142 (1,229) N, resulting in high compressive strains at the distal (2,718 (1,698) µε) and proximal radius (3,664 (1,890) µε). We successfully reproduced consistent fracture patterns in response to dynamic loads. The fracture energy and forces reported here are lower and the strains are higher than those previously reported and can likely be attributed to the controlled, incremental, dynamic nature of the applied loads.

  11. A novel in vivo impact device for evaluation of sudden limb loading response.

    PubMed

    Boutwell, Erin; Stine, Rebecca; Gard, Steven

    2015-01-01

    The lower limbs are subjected to large impact forces on a daily basis during gait, and ambulators rely on various mechanisms to protect the musculoskeletal system from these potentially damaging shocks. However, it is difficult to assess the efficacy of anatomical mechanisms and potential clinical interventions on impact forces because of limitations of the testing environment. The current paper describes a new in vivo measurement device (sudden loading evaluation device, or SLED) designed to address shortcomings of previous loading protocols. To establish the repeatability and validity of this testing device, reliability and human participant data were collected while the stiffnesses of simulated and prosthetic limbs were systematically varied. The peak impact forces delivered by the SLED ranged from 706±3 N to 2157±32 N during reliability testing and from 784±30 N to 938±18 N with the human participant. The relatively low standard deviations indicate good reliability within the impacts delivered by the SLED, while the magnitude of the loads experienced by the human participant (98-117% BW) were comparable to ground reaction forces during level walking. Thus, the SLED may be valuable as a research tool for investigations of lower-limb impact loading events. Published by Elsevier Ltd.

  12. Damage Tolerance of Pre-Stressed Composite Panels Under Impact Loads

    NASA Astrophysics Data System (ADS)

    Johnson, Alastair F.; Toso-Pentecôte, Nathalie; Schueler, Dominik

    2014-02-01

    An experimental test campaign studied the structural integrity of carbon fibre/epoxy panels preloaded in tension or compression then subjected to gas gun impact tests causing significant damage. The test programme used representative composite aircraft fuselage panels composed of aerospace carbon fibre toughened epoxy prepreg laminates. Preload levels in tension were representative of design limit loads for fuselage panels of this size, and maximum compression preloads were in the post-buckle region. Two main impact scenarios were considered: notch damage from a 12 mm steel cube projectile, at velocities in the range 93-136 m/s; blunt impact damage from 25 mm diameter glass balls, at velocities 64-86 m/s. The combined influence of preload and impact damage on panel residual strengths was measured and results analysed in the context of damage tolerance requirements for composite aircraft panels. The tests showed structural integrity well above design limit loads for composite panels preloaded in tension and compression with visible notch impact damage from hard body impact tests. However, blunt impact tests on buckled compression loaded panels caused large delamination damage regions which lowered plate bending stiffness and reduced significantly compression strengths in buckling.

  13. Creatine loading does not impact on stroke performance in tennis.

    PubMed

    Eijnde, B O; Vergauwen, L; Hespel, P

    2001-01-01

    The effect of acute creatine supplementation on stroke quality was investigated during simulated match play. Well-trained tennis players reported to the test center on two occasions. On each occasion they performed the Leuven Tennis Performance Test (LTPT) and a 70 m shuttle run (SHR). During 5 days prior to each test session they received in random order and according to a double-blind cross-over study design either oral creatine supplements (4 x 5 g per day) or placebo. The two experimental periods were separated by a 5-week washout period. Stroke quality was evaluated during the LTPT by means of registration of error rate and measurement of ball velocity and precision of lateral and longitudinal ball placement. Compared with placebo, creatine supplementation did not significantly impact on either power or precision of first and second services, baseline strokes in neutral and defensive rallies, and volleys. Shuttle run time was 19.87 +/- 0.30 sec during placebo versus 19.85 +/- 0.27 sec during creatine treatment. Acute creatine supplementation does not enhance stroke performance or sprint power in match-like conditions in elite tennis players.

  14. High intensity performance and upgrades at the Brookhaven AGS

    SciTech Connect

    Roser, T.

    1998-12-01

    The high intensity proton beam of the AGS is used both for the slow-extracted-beam (SEB) area with many target station to produce secondary beams and the fast-extracted-beam (FEB) line used for the production of muons for the g-2 experiment and for high intensity target testing for the spallation neutron sources and muon production targets for the muon collider. The same FEB line will also be used for the transfer of beam to RHIC. The proton beam intensity in the AGS has increased steadily over the 35 year existence of the AGS, but the most dramatic increase occurred over the last couple of years with the addition of the new AGS Booster. All modifications associated with this are discussed.

  15. Short-pulse, high-intensity lasers at Los Alamos

    SciTech Connect

    Taylor, A.J.; Roberts, J.P.; Rodriguez, G.; Fulton, R.D.; Kyrala, G.A.; Schappert, G.T.

    1994-03-01

    Advances in ultrafast lasers and optical amplifiers have spurred the development of terawatt-class laser systems capable of delivering focal spot intensities approaching 10{sup 20} W/cm{sup 2}. At these extremely high intensities, the optical field strength is more than twenty times larger than the Bohr electric field, permitting investigations of the optical properties of matter in a previously unexplored regime. The authors describe two laser systems for high intensity laser interaction experiments: The first is a terawatt system based on amplification of femtosecond pulses in XeCl which yields 250 mJ in 275 fs and routinely produces intensifies on target in excess of 10{sup 18} W/cm{sup 2}. The second system is based on chirped pulse amplification of 100-fs pulses in Ti:sapphire.

  16. Plasma-based polarization modulator for high-intensity lasers

    NASA Astrophysics Data System (ADS)

    Chen, Zi-Yu; Pukhov, Alexander

    2016-12-01

    Manipulation of laser pulses at high intensities is an important yet challenging issue. New types of plasma-based optical devices are promising alternatives to achieve this goal. Here we propose to modulate the polarization state of intense lasers based on oblique reflection from solid-plasma surfaces. A new analytical description is presented considering the plasma as an uniaxial medium that causes birefringence effect. Particle-in-cell simulation results numerically demonstrate that such a scheme can provide a tunable polarization control of the laser pulses even in the relativistic regime. The results are thus relevant for the design of compact, easy to use, and versatile polarization modulators for high-intensity laser pulses.

  17. Chrome tannage using high-intensity ultrasonic field.

    PubMed

    Mäntysalo, E; Marjoniemi, M; Kilpeläinen, M

    1997-04-01

    The process time in chrome tannage in leather making, using an elastic compression cycle followed by irradiation by high-intensity ultrasound, is quite short lasting only a few minutes, compared with a process time of several hours in modern chrome tannage. After ultrasonic irradiation, samples were basified in 17 h in chrome liquor at a pH of 4.0 and the shrinkage temperature was measured. The determination of the efficiency for the chrome liquor penetrating into the hides can be based on the steepness of the shrinkage temperature-processing time curve. An approximate value of 20 degrees C min(-1) can be evaluated for the initial slope of the curve when elastic compression and high-intensity ultrasonic irradiation is used, and a processing time of 2 min is required in chrome liquor (plus 17 h basification and 24 h storage time) to obtain leather stable to boiling. Usually, hides are kept in chrome liquor for 2 h.

  18. Engineering Food Ingredients with High-Intensity Ultrasound

    NASA Astrophysics Data System (ADS)

    Weiss, Jochen; Kristbergsson, Kristberg; Kjartansson, Gunnar Thor

    The use of ultrasound in the food industry has increased in the last decades. Ultrasound has been used both to analyze food structure and composition at low ultrasonic intensities and high frequencies and to modify ingredients at high ultrasonic intensities and low frequencies. Application of the latter is referred to as high-intensity (power) ultrasonication and is generally carried out at frequencies of =0.1 MHz and ultrasonic intensities of 10-100 W cm-2. In the food industry, power ultrasonication has proved to be a highly effective food processing and preservation technology, and use of high-intensity ultrasound with or without heat may be used, for example, to denature enzymes, aid in the extraction of valuable compounds from plants and seeds, tenderize meat, and homogenize or disperse two-phase systems such as emulsions or suspensions (Mason et al., 1996).

  19. Review of High-intensity Interval Training in Cardiac Rehabilitation.

    PubMed

    Ito, Shigenori; Mizoguchi, Tatsuya; Saeki, Tomoaki

    2016-01-01

    For the secondary prevention of cardiovascular disease, comprehensive cardiac rehabilitation is required. This involves optimal medical therapy, education on nutrition and exercise therapy, and smoking cessation. Of these, efficient exercise therapy is a key factor. A highly effective training protocol is therefore warranted, which requires a high rate of compliance. Although moderate-intensity continuous training has been the main training regimen recommended in cardiac rehabilitation guidelines, high-intensity interval training has been reported to be more effective in the clinical and experimental setting from the standpoint of peak oxygen uptake and central and peripheral adaptations. In this review, we illustrate the scientific evidence for high-intensity interval training. We then verify this evidence and discuss its significance and the remaining issues.

  20. Response of graphene to femtosecond high-intensity laser irradiation

    SciTech Connect

    Roberts, Adam; Cormode, Daniel; Reynolds, Collin; Newhouse-Illige, Ty; LeRoy, Brian J.; Sandhu, Arvinder S.

    2011-08-01

    We study the response of graphene to high-intensity, 50-femtosecond laser pulse excitation. We establish that graphene has a high ({approx}3 x 10{sup 12} Wcm{sup -2}) single-shot damage threshold. Above this threshold, a single laser pulse cleanly ablates graphene, leaving microscopically defined edges. Below this threshold, we observe laser-induced defect formation leading to degradation of the lattice over multiple exposures. We identify the lattice modification processes through in-situ Raman microscopy. The effective lifetime of chemical vapor deposition grown graphene under femtosecond near-infrared irradiation and its dependence on laser intensity is determined. These results also define the limits of non-linear applications of graphene in femtosecond high-intensity regime.

  1. Enhancement of vasorelaxation in hypertension following high-intensity exercise.

    PubMed

    Yang, Ai-Lun; Lo, Chia-Wen; Lee, Jen-Ting; Su, Chia-Ting

    2011-04-30

    Exercise can ameliorate vascular dysfunction in hypertension, but its underlying mechanism has not been explored thoroughly. We aimed to investigate whether the high-intensity exercise could enhance vasorelaxation mediated by insulin and insulin-like growth factor-1 (IGF-1) in hypertension. Sixteen-week-old spontaneously hypertensive rats were randomly divided into non-exercise sedentary (SHR) and high-intensity exercise (SHR+Ex) groups conducted by treadmill running at a speed of 30 m/ min until exhaustion. Age-matched Wistar-Kyoto rats (WKY) were used as the normotensive control group. Immediately after exercise, the agonist-induced vasorelaxation of aortas was evaluated in organ baths with or without endothelial denudation. Selective inhibitors were used to examine the roles of nitric oxide synthase (NOS) and phosphatidylinositol-3 kinase (PI3K) in the vasorelaxation. By adding superoxide dismutase (SOD), a superoxide scavenger, the role of superoxide production in the vasorelaxation was also clarified. We found that, the high-intensity exercise significantly (P < 0.05) induced higher vasorelaxant responses to insulin and IGF-1 in the SHR+Ex group than that in the SHR group; after endothelial denudation and pre-treatment of the PI3K inhibitor, NOS inhibitor, or SOD, vasorelaxant responses to insulin and IGF-1 became similar among three groups; the protein expression of insulin receptor, IGF-1 receptor, and endothelial NOS (eNOS) was significantly (P < 0.05) increased in the SHR+Ex group compared with the SHR group;] the relaxation to sodium nitroprusside, a NO donor, was not different among three groups. Our findings suggested that the high-intensity exercise ameliorated the insulin- and IGF-1-mediated vasorelaxation through the endothelium-dependent pathway, which was associated with the reduced level of superoxide production.

  2. Spallation neutron source and other high intensity froton sources

    SciTech Connect

    Weiren Chou

    2003-02-06

    This lecture is an introduction to the design of a spallation neutron source and other high intensity proton sources. It discusses two different approaches: linac-based and synchrotron-based. The requirements and design concepts of each approach are presented. The advantages and disadvantages are compared. A brief review of existing machines and those under construction and proposed is also given. An R&D program is included in an appendix.

  3. Silicone rubber curing by high intensity infrared radiation

    NASA Astrophysics Data System (ADS)

    Huang, Tung-Way; Tsai, Jen-Hui; Cherng, Chung-Pin; Chen, Jan-Ku

    1994-08-01

    A high-intensity (12 kW) and compact (80 cm) infrared heating oven for fast curing (12 seconds) of tube-like silicone rubber curing studies is reported. Quality inspection by DSC and DMA and results from pilot-scale curing oven all suggest that infrared heating provides a better way of vulcanization regarding to curing time, quality, cost, and spacing over conventional hot air heating.

  4. Silicone rubber curing by high intensity infrared radiation

    SciTech Connect

    Huang, T.; Tsai, J.; Cherng, C.; Chen, J.

    1994-08-10

    A high-intensity (12 kW) and compact (80 cm) infrared heating oven for fast curing (12 seconds) of tube-like silicone rubber curing studies is reported. Quality inspection by DSC and DMA and results from pilot-scale curing oven all suggest that infrared heating provides a better way of vulcanization regarding to curing time, quality, cost, and spacing over conventional hot air heating. {copyright} {ital 1995} {ital American} {ital Institute} {ital of} {ital Physics}.

  5. HIGH-INTENSITY, HIGH CHARGE-STATE HEAVY ION SOURCES

    SciTech Connect

    ALESSI,J.G.

    2004-08-16

    There are many accelerator applications for high intensity heavy ion sources, with recent needs including dc beams for RIA, and pulsed beams for injection into synchrotrons such as RHIC and LHC. The present status of sources producing high currents of high charge state heavy ions is reviewed. These sources include ECR, EBIS, and Laser ion sources. Benefits and limitations for these type sources are described. Possible future improvements in these sources are also mentioned.

  6. PULSED POWER APPLICATIONS IN HIGH INTENSITY PROTON RINGS.

    SciTech Connect

    ZHANG, S.Y.; SANDBERG, J.; ET AL.

    2005-05-16

    Pulsed power technology has been applied in particle accelerators and storage rings for over four decades. It is most commonly used in injection, extraction, beam manipulation, source, and focusing systems. These systems belong to the class of repetitive pulsed power. In this presentation, we review and discuss the history, present status, and future challenge of pulsed power applications in high intensity proton accelerators and storage rings.

  7. Impact of enzyme loading on the efficacy and recovery of cellulolytic enzymes immobilized on enzymogel nanoparticles.

    PubMed

    Samaratunga, Ashani; Kudina, Olena; Nahar, Nurun; Zakharchenko, Andrey; Minko, Sergiy; Voronov, Andriy; Pryor, Scott W

    2015-03-01

    Cellulase and β-glucosidase were adsorbed on a polyacrylic acid polymer brush grafted on silica nanoparticles to produce enzymogels as a form of enzyme immobilization. Enzyme loading on the enzymogels was increased to a saturation level of approximately 110 μg (protein) mg(-1) (particle) for each enzyme. Enzymogels with varied enzyme loadings were then used to determine the impact on hydrolysis rate and enzyme recovery. Soluble sugar concentrations during the hydrolysis of filter paper and Solka-Floc with the enzymogels were 45 and 53%, respectively, of concentrations when using free cellulase. β-Glucosidase enzymogels showed lower performance; hydrolyzate glucose concentrations were just 38% of those using free enzymes. Increasing enzyme loading on the enzymogels did not reduce net efficacy for cellulase and improved efficacy for β-glucosidase. The use of free cellulases and cellulase enzymogels resulted in hydrolyzates with different proportions of cellobiose and glucose, suggesting differential attachment or efficacy of endoglucanases, exoglucanases, and β-glucosidases present in cellulase mixtures. When loading β-glucosidase individually, higher enzyme loadings on the enzymogels produced higher hydrolyzate glucose concentrations. Approximately 96% of cellulase and 66 % of β-glucosidase were recovered on the enzymogels, while enzyme loading level did not impact recovery for either enzyme.

  8. Ion source and injection line for high intensity medical cyclotron

    SciTech Connect

    Jia, XianLu Guan, Fengping; Yao, Hongjuan; Zhang, TianJue; Yang, Jianjun; Song, Guofang; Ge, Tao; Qin, Jiuchang

    2014-02-15

    A 14 MeV high intensity compact cyclotron, CYCIAE-14, was built at China Institute of Atomic Energy (CIAE). An injection system based on the external H− ion source was used on CYCIAE-14 so as to provide high intensity beam, while most positron emission tomography cyclotrons adopt internal ion source. A beam intensity of 100 μA/14 MeV was extracted from the cyclotron with a small multi-cusp H− ion source (CIAE-CH-I type) and a short injection line, which the H− ion source of 3 mA/25 keV H− beam with emittance of 0.3π mm mrad and the injection line of with only 1.2 m from the extraction of ion source to the medial plane of the cyclotron. To increase the extracted beam intensity of the cyclotron, a new ion source (CIAE-CH-II type) of 9.1 mA was used, with maximum of 500 μA was achieved from the cyclotron. The design and test results of the ion source and injection line optimized for high intensity acceleration will be given in this paper.

  9. Modelling catchment management impact on in-stream phosphorus loads in northern Victoria.

    PubMed

    Vigiak, O; Rattray, D; McInnes, J; Newham, L T H; Roberts, A M

    2012-11-15

    Phosphorus pollution severely impairs the water quality of rivers in Australia and worldwide. Conceptual models have proved useful to assess management impact on phosphorus loads, particularly in data-sparse environments. This paper develops and evaluates the coupling of a point-scale model (HowLeaky2008) to a catchment scale model (CatchMODS) to enhance modelling of farm management impacts on in-stream phosphorus loads. The model was tested in two adjacent catchments in northern Victoria (Avon-Richardson and Avoca), Australia. After calibration of the in-stream attenuation parameter against measurements at gauging stations, the model simulated specific annual phosphorus loads across the catchments well (Nash-Sutcliffe model efficiency of 0.52 in the Avon-Richardson and 0.83 for the Avoca catchment). Phosphorus loads at both catchment outlets under current conditions were estimated at 7 t y(-1) and were dominated by field exports. Changes to farm management practices, i.e. the use of perennial pastures in grazing systems and zero-tillage in cropping systems were estimated to reduce phosphorus load by 31% in the Avon-Richardson catchment and 19% in the Avoca catchment, relative to current practices (annual pasture and minimum tillage). The model afforded a major improvement in conceptual modelling by explicit simulation of the impacts of soil and climatic conditions on field-scale exports and by placing them in the context of landscape processes.

  10. Atmospheric and Wake Turbulence Impacts on Wind Turbine Fatigue Loading: Preprint

    SciTech Connect

    Lee, S.; Churchfield, M.; Moriarty, P.; Jonkman, J.; Michalakes, J.

    2011-12-01

    Large-eddy simulations of atmospheric boundary layers under various stability and surface roughness conditions are performed to investigate the turbulence impact on wind turbines. In particular, the aeroelastic responses of the turbines are studied to characterize the fatigue loading of the turbulence present in the boundary layer and in the wake of the turbines. Two utility-scale 5 MW turbines that are separated by seven rotor diameters are placed in a 3 km by 3 km by 1 km domain. They are subjected to atmospheric turbulent boundary layer flow and data is collected on the structural response of the turbine components. The surface roughness was found to increase the fatigue loads while the atmospheric instability had a small influence. Furthermore, the downstream turbines yielded higher fatigue loads indicating that the turbulent wakes generated from the upstream turbines have significant impact.

  11. Dynamic response of aluminum honeycombs to in-plane impact loadings

    NASA Astrophysics Data System (ADS)

    Tanaka, Koichi; Nishida, Masahiro; Mochida, Toshiharu; Kousaka, Akiko

    2001-04-01

    Deformation processes of aluminum honeycombs with hexagonal cells subjected to the in-plane impact of a rigid impactor are investigated experimentally and numerically in relation to the dynamical behavior of cellular materials and complex materials under high-speed loadings. Strain waves are measured using strain gauges glued on the cell walls and reaction forces are measured using a load cell at the contact surface between the honeycomb and a fixed wall. A high-speed camera is used to visualize the deformation process. Numerical simulations are partly made for the same configuration as the experiment. Very distinctive deformation mechanisms of individual cells and propagation mechanisms of strain waves in the honeycomb are found out. Also, characteristic two-dimensional behavior is revealed in spite of one-dimensional and uni-directional impact loading.

  12. Muscle fatigue during high-intensity exercise in children.

    PubMed

    Ratel, Sébastien; Duché, Pascale; Williams, Craig A

    2006-01-01

    Children are able to resist fatigue better than adults during one or several repeated high-intensity exercise bouts. This finding has been reported by measuring mechanical force or power output profiles during sustained isometric maximal contractions or repeated bouts of high-intensity dynamic exercises. The ability of children to better maintain performance during repeated high-intensity exercise bouts could be related to their lower level of fatigue during exercise and/or faster recovery following exercise. This may be explained by muscle characteristics of children, which are quantitatively and qualitatively different to those of adults. Children have less muscle mass than adults and hence, generate lower absolute power during high-intensity exercise. Some researchers also showed that children were equipped better for oxidative than glycolytic pathways during exercise, which would lead to a lower accumulation of muscle by-products. Furthermore, some reports indicated that the lower ability of children to activate their type II muscle fibres would also explain their greater resistance to fatigue during sustained maximal contractions. The lower accumulation of muscle by-products observed in children may be suggestive of a reduced metabolic signal, which induces lower ratings of perceived exertion. Factors such as faster phosphocreatine resynthesis, greater oxidative capacity, better acid-base regulation, faster readjustment of initial cardiorespiratory parameters and higher removal of metabolic by-products in children could also explain their faster recovery following high-intensity exercise.From a clinical point of view, muscle fatigue profiles are different between healthy children and children with muscle and metabolic diseases. Studies of dystrophic muscles in children indicated contradictory findings of changes in contractile properties and the muscle fatigability. Some have found that the muscle of boys with Duchenne muscular dystrophy (DMD) fatigued less

  13. Impacts of Climate Change on Electric Transmission Capacity and Peak Electricity Load in the United States

    NASA Astrophysics Data System (ADS)

    Chester, M.; Bartos, M. D.; Eisenberg, D. A.; Gorman, B.; Johnson, N.

    2015-12-01

    Climate change may hinder future electricity reliability by reducing electric transmission capacity while simultaneously increasing electricity demand. This study estimates potential climate impacts to electric transmission capacity and peak electricity load in the United States. Electric power cables suffer decreased transmission capacity as they get hotter; similarly, during the summer peak period, electricity demand typically increases with hotter ambient air temperatures due to increased cooling loads. As atmospheric carbon concentrations increase, higher air temperatures may strain power infrastructure by reducing transmission capacity and increasing peak electricity loads. Taken together, these coincident impacts may have unpredictable consequences for electric power reliability. We estimate the effects of climate change on both the rated capacity of transmission infrastructure and expected electricity demand for 120 electrical utilities across the United States. We estimate climate-attributable capacity reductions to transmission lines by constructing thermal models of representative conductors, then forcing these models with downscaled CMIP5 temperature projections to determine the relative change in rated ampacity over the twenty-first century. Next, we assess the impact of climate change on electricity demand by using historical relationships between ambient temperature and utility-scale summertime peak load to estimate the extent to which climate change will incur additional peak load increases. We use downscaled temperature projections from 11 CMIP5 GCM models under 3 atmospheric carbon scenarios. We find that by mid-century (2040-2060), climate change may reduce average summertime transmission capacity by 4-6% relative to the 1990-2010 reference period. At the same time, peak summertime loads may rise by roughly 2-12% on average due to increases in daily maximum air temperature. In the absence of energy efficiency gains, demand-side management programs

  14. Impact of Interruptions, Distractions, and Cognitive Load on Procedure Failures and Medication Administration Errors.

    PubMed

    Thomas, Lily; Donohue-Porter, Patricia; Stein Fishbein, Joanna

    Medication administration errors are difficult to intercept since they occur at the end of the process. The study describes interruptions, distractions, and cognitive load experienced by registered nurses during medication administration and explores their impact on procedure failures and medication administration errors. The focus of this study was unique as it investigated how known individual and environmental factors interacted and culminated in errors.

  15. Reliability of accelerometry to assess impact loads of jumping and landing tasks.

    PubMed

    Simons, Chantal; Bradshaw, Elizabeth J

    2016-01-01

    Overuse injuries, resulting from repetitive subacute impact loading, are a problem in high-performance sports. Monitoring of impact loading may aid in the prevention of these injuries. The current study aimed to establish the intra-day and inter-day reliability of a tri-axial accelerometer to assess impact loading during jumping and landing tasks. Twelve participants wore an accelerometer on their upper and lower back. They performed a continuous hopping task as well as drop landings and rebound jumps from three drop heights (37.5, 57.5 and 77.5 cm), peak resultant acceleration (PRA) was calculated for all tasks. The tasks were performed twice, one week apart at the same time of day. The difference in the mean, intra-class correlation coefficient, coefficient of variation and Cohen's effect size were calculated as measures of reliability. PRA showed good intra-day reliability for the hopping task. Inter-day reliability of the PRA was moderate to good across all tasks. Reliability of PRA was slightly higher when accelerations were recorded on the lower back compared to the upper back. To assess impact loading, during continuous hopping, drop landings and rebound jumps, PRA recorded at both the upper and lower back appears to be a reliable measure.

  16. Antisymmetric and Symmetric Functionally Graded Plate-Type Structures Impacted by Blast Loading

    DTIC Science & Technology

    2010-09-13

    IMPACTED BY BLAST LOADING Terry Hause, Ph.D. Research Mechanical Engineer U.S. Army RDECOM-TARDEC Warren, MI 48397 Sudhakar, Arepally Deputy...CONTRACT NUMBER 5b. GRANT NUMBER 5c. PROGRAM ELEMENT NUMBER 6. AUTHOR(S) Terry Hause, Ph.D.; Sudhakar, Arepally 5d. PROJECT NUMBER 5e. TASK NUMBER

  17. Seating load parameters impact on dental ceramic reinforcement conferred by cementation with resin-cements.

    PubMed

    Addison, Owen; Sodhi, Amandeep; Fleming, Garry J P

    2010-09-01

    Cementation of all-ceramic restorations with resin-cements has been demonstrated to reduce the incidence of fracture in service. The aim was to investigate the influence of loading force and loading duration applied during cementation on the reinforcement conferred by a resin-cement on a leucite reinforced glass-ceramic. 210 glass-ceramic discs (12 mm diameter, 0.8 mm thickness) were allocated to seven groups (n=30). The bi-axial flexure strength (BFS) was determined for 'as-fired' specimens (group A), following HF-acid etching (group B) and following etching and centrally loading on a semi-compliant substrate with 30 N for 300 s (group C). Further etched specimens were coated with Rely-X Unicem resin-cement under cementation loading of 5 or 30 N, for 60 or 300 s (groups D-F) prior to BFS determination using multilayered analytical solutions. BFS data was compared using factorial or one-way analyses of variance and the Weibull analysis. HF-acid etching of the 'as-fired' surface resulted in a significant reduction in mean BFS (P<0.001) whereas resin-cementation subsequently conferred significant strengthening (P<0.001) ranging from 24 to 38% and dependent on the loading parameters employed. A factorial significance (P=0.004) of seating load (5 or 30 N) and significant factorial interaction (P<0.001) of seating load and load duration (60 or 300 s) on the mean BFS were identified. The magnitude of resin-reinforcement conferred was sensitive to the loading parameters investigated although the mechanisms underlying the variation appear complex. Similar patterns of variability can be expected clinically impacting on the clinical longevity of resin-cemented glass-ceramic restorations. Copyright 2010 Academy of Dental Materials. Published by Elsevier Ltd. All rights reserved.

  18. Virtual coaching for the high-intensity training of a powerlifter following coronary artery bypass grafting

    PubMed Central

    Adams, Richard; Qin, Huanying; Bilbrey, Tim; Schussler, Jeffrey M.

    2015-01-01

    A 55-year-old powerlifter in Tennessee learned about the sport-specific, high-intensity cardiac rehabilitation training available in Dallas, Texas, and contacted the staff by phone. He was recovering from quadruple coronary artery bypass grafting (CABG) and had completed several weeks of traditional cardiac rehabilitation in his hometown, but the exercise program no longer met his needs. He wanted help in returning both to his normal training regimen and to powerlifting competition but was unable to attend the Dallas program in person. An exercise physiologist with the program devised a virtual coaching model in which the patient was sent a wrist blood pressure cuff for self-monitoring and was advised about exercises that would not harm his healing sternum, even as the weight loads were gradually increased. After 17 weeks of symptom-limited, high-intensity training that was complemented by phone and e-mail support, the patient was lifting heavier loads than he had before CABG. At a powerlifting competition 10 months after CABG, he placed first in his age group. This case report exemplifies the need for alternative approaches to the delivery of cardiac rehabilitation services. PMID:25552808

  19. Virtual coaching for the high-intensity training of a powerlifter following coronary artery bypass grafting.

    PubMed

    Adams, Richard; Adams, Jenny; Qin, Huanying; Bilbrey, Tim; Schussler, Jeffrey M

    2015-01-01

    A 55-year-old powerlifter in Tennessee learned about the sport-specific, high-intensity cardiac rehabilitation training available in Dallas, Texas, and contacted the staff by phone. He was recovering from quadruple coronary artery bypass grafting (CABG) and had completed several weeks of traditional cardiac rehabilitation in his hometown, but the exercise program no longer met his needs. He wanted help in returning both to his normal training regimen and to powerlifting competition but was unable to attend the Dallas program in person. An exercise physiologist with the program devised a virtual coaching model in which the patient was sent a wrist blood pressure cuff for self-monitoring and was advised about exercises that would not harm his healing sternum, even as the weight loads were gradually increased. After 17 weeks of symptom-limited, high-intensity training that was complemented by phone and e-mail support, the patient was lifting heavier loads than he had before CABG. At a powerlifting competition 10 months after CABG, he placed first in his age group. This case report exemplifies the need for alternative approaches to the delivery of cardiac rehabilitation services.

  20. Commissioning the new high power rf system for the AGS with high intensity beam

    SciTech Connect

    Brennan, J.M.; Ciardullo, D.J.; Deng, D.P; Hayes, T.; Onillon, E.; Otis, A.; Sanders, R.T.; Zaltsman, A.

    1994-08-01

    A new high power rf system has been installed in the AGS in order to raise the beam loading limit to beyond 6 {times} 10{sup 13} protons per pulse. The old system was limited to 2.2 {times} 10{sup l3} ppp by: available real power, multi-loop instability, and transient beam loading during batch filling from the Booster. The key components of the new system are: new power amplifiers in the tunnel using the Thomson-CSF TH573 300kW tetrode, rf feedback around the power stage, and reduction of the 10 cavities` R/Q by 1.8 by additional gap capacitors. Commissioning of the new rf system with high intensity beam is described. The intensity goal for the 1994 running period is 4 {times} 10{sup 13} ppp. To date, 3.7 {times} 10{sup 13} ppp has been achieved.

  1. [Response of a finite element model of the pelvis to different side impact loads].

    PubMed

    Ruan, Shijie; Zheng, Huijing; Li, Haiyan; Zhao, Wei

    2013-08-01

    The pelvis is one of the most likely affected areas of the human body in case of side impact, especially while people suffer from motor vehicle crashes. With the investigation of pelvis injury on side impact, the injury biomechanical behavior of pelvis can be found, and the data can help design the vehicle security devices to keep the safety of the occupants. In this study, a finite element (FE) model of an isolated human pelvis was used to study the pelvic dynamic response under different side impact conditions. Fracture threshold was established by applying lateral loads of 1000, 2000, 3000, 4000 and 5000 N, respectively, to the articular surface of the right acetabulum. It was observed that the smaller the lateral loads were, the smaller the von Mises stress and the displacement in the direction of impact were. It was also found that the failure threshold load was near 3000 N, based on the fact that the peak stress would not exceed the average compressive strength of the cortical bone. It could well be concluded that with better design of car-door and hip-pad so that the side impact force was brought down to 3000 N or lower, the pelvis would not be injured.

  2. Impacting load control of floating supported friction plate and its experimental verification

    NASA Astrophysics Data System (ADS)

    Ning, Keyan; Wang, Yu; Huang, Dingchuan; Yin, Lei

    2017-05-01

    Friction plates are key components in automobile transmission system. Unfortunately, due to the tough working condition i.e. high impact, high temperature, fracture and plastic deformation are easily observed in friction plates. In order to reduce the impact load and increase the impact resistance and life span of the friction plate. This paper presents a variable damping design method and structure, by punching holes in the key position of the friction plate and filling it with damping materials, the impact load of the floating support friction plate can be controlled. Simulation is applied to study the effect of the position and number of damping holes on tooth root stress. Furthermore, physic test was designed and conducted to validate the correctness and effectiveness of the proposed method. Test result shows that the impact load of the new structure is reduced by 40% and its fatigue life is 4.7 times larger. The new structure provides a new way for floating supported friction plates design.

  3. Statistics concerning the Apollo command module water landing, including the probability of occurrence of various impact conditions, sucessful impact, and body X-axis loads

    NASA Technical Reports Server (NTRS)

    Whitnah, A. M.; Howes, D. B.

    1971-01-01

    Statistical information for the Apollo command module water landings is presented. This information includes the probability of occurrence of various impact conditions, a successful impact, and body X-axis loads of various magnitudes.

  4. Potential Causes of Elevated REE following High-Intensity Exercise.

    PubMed

    Hunter, Gary R; Moellering, Douglas R; Carter, Stephen J; Gower, Barbara A; Bamman, Marcas M; Hornbuckle, Lyndsey M; Plaisance, Eric P; Fisher, Gordon

    2017-07-21

    Resting energy expenditure (REE) increases following intense exercise; however, little is known concerning mechanisms. Determine effects of a single bout of moderate-intensity continuous aerobic exercise (MIC), or high intensity interval exercise (HII) on REE under energy balance conditions. Thirty-three untrained premenopausal women were evaluated at baseline, after 8-16 weeks of training, 22 hours following either MIC (50% peak VO2) or HII (84% peak VO2). Participants were in a room calorimeter during and following the exercise challenge. Food intake was adjusted to obtain energy balance across 23 hours. REE was measured after 22 hours following all conditions. Twenty-three hour urine norepinephrine concentration and serum creatine kinase activity (CrKact) were obtained. Muscle biopsies were obtained in a subset of 15 participants to examine muscle mitochondrial state 2, 3, and 4 fat oxidation. REE was increased 22 hours following MIC (64±119 kcal) and HII (103±137 kcal). Markers of muscle damage (CrKact) increased following HII (9.6±25.5 units/liter) and MIC (22.2±22.8 units/liter) while sympathetic tone (urine norepinephrine) increased following HII (1.1±10.6 ng/mg). Uncoupled phosphorylation (states 2 and 4) fat oxidation were related to REE (respectively r=0.65 and r=0.55); however, neither state 2 or 4 fat oxidation increased following MIC or HII. REE was not increased following 8 weeks of aerobic training when exercise was restrained for 60 hours. Under energy balance conditions REE increased 22 hours following both moderate intensity and high intensity exercise. Exercise-induced muscle damage/repair and increased sympathetic tone may contribute to increased REE whereas uncoupled phosphorylation does not. These results suggest that moderate to high intensity exercise may be valuable for increasing energy expenditure for at least 22 hours following the exercise.

  5. The development of a high intensity dance performance fitness test.

    PubMed

    Redding, Emma; Weller, Peter; Ehrenberg, Shantel; Irvine, Sarah; Quin, Edel; Rafferty, Sonia; Wyon, Matthew; Cox, Carol

    2009-01-01

    While there is currently a validated dance-specific exercise method of measuring aerobic fitness, no such test has been developed to measure high intensity capabilities in dance. The purpose of this study was to initiate an intermittent high intensity dance-specific fitness test. The test was designed to be able to observe changes in heart rate (HR), thereby allowing for a measurement of physical fitness at high intensities. Sixteen professional dancers (4 males and 12 females) volunteered to take part in this study. The fitness test protocol consists of movements that are representative of contemporary dance, and contains exercise and rest periods that mimic the intermittent nature of dance. The participants performed four trials. The physiological variables measured were HR (b.min(-1)) for each one minute bout of the four minute test for all trials, oxygen uptake (VO(2)) throughout the test, and end blood lactate (BLa mmol.L) for each trial. In addition, five of the participants undertook a maximal oxygen uptake treadmill test, and the scores obtained were compared with those from the dance test. Results show HR consistency across each one minute bout of the test and across each of the four trials of testing for all participants, indicating that the test is reliable. There was good reliability between bouts of each trial (typical error as % of CV = 1.5), intraclass "r" = 0.8, and good reliability between the four trials (typical error as % of CV = 2.1), intraclass "r" = 0.82. There were no significant differences between the maximal VO(2) and BLa scores established in the treadmill and dance tests, demonstrating validity. Thus, the results of this study indicate that the high intensity dance-specific test is a reliable and valid means of assessing and monitoring the cardiovascular fitness of dancers. The test allows dancers to be assessed within an environment that they are accustomed to (the studio), using a mode of exercise that is relevant (dance), and it is

  6. High Intensity 2-Photon Photoassociation Spectroscopy of Strontium

    NASA Astrophysics Data System (ADS)

    Nagel, S. B.; Martinez, Y. N.; Mickelson, P. G.; Killian, T. C.

    2007-06-01

    We perform high intensity, 2-photon photoassociation spectroscopy near the 461 nm ^1S0-^1P1 transition of strontium to determine the binding energy of the least bound level in the ground state atomic potential. Previous work by our group has constrained the value of the s-wave scattering length in both ^86Sr and ^88Sr. This work provides a more precise value of the s-wave scattering lengths using the newly-determined binding energy, thus informing efforts to attain quantum degeneracy in strontium.

  7. HELIOS: A high intensity chopper spectrometer at LANSCE

    SciTech Connect

    Mason, T.E.; Broholm, C.; Fultz, B.

    1998-12-31

    A proposal to construct a high intensity chopper spectrometer at LANSCE as part of the SPSS upgrade project is discussed. HELIOS will be optimized for science requiring high sensitivity neutron spectroscopy. This includes studies of phonon density of states in small polycrystalline samples, magnetic excitations in quantum magnets and highly correlated electron systems, as well as parametric studies (as a function of pressure, temperature, or magnetic field) of S(Q,{omega}). By employing a compact design together with the use of supermirror guide in the incident flight path the neutron flux at HELIOS will be significantly higher than any other comparable instrument now operating.

  8. High-intensity tone generation by aeroacoustic sources

    NASA Technical Reports Server (NTRS)

    Shakkottai, P.; Kwack, E. Y.; Cho, Y. I.; Back, L. H.

    1987-01-01

    An experimental investigation has been carried out on the production of high-intensity tones by axisymmetric ring cavities. Maximum sound production occurs during an acoustic resonance at Strouhal numbers, which depend only on the local flow velocity independent of cavity location. Values of sound pressure of about 115 dB at 1-m distance can be generated by axisymmetric ring cavities on projectiles moving at a relatively low flight speed equal to 70 m/s. Frequencies in the audible range up to several kilohertz can be generated aeroacoustically. A simple analytical model has been developed to explain the experimental observations.

  9. Ultra-High Intensity Proton Accelerators and their Applications

    SciTech Connect

    Weng, W. T.

    1997-12-31

    The science and technology of proton accelerators have progressed considerably in the past three decades. Three to four orders of magnitude increase in both peak intensity and average flux have made it possible to construct high intensity proton accelerators for modern applications, such as: spallation neutron sources, kaon factory, accelerator production of tritium, energy amplifier and muon collider drivers. The accelerator design focus switched over from intensity for synchrotrons, to brightness for colliders to halos for spallation sources. An overview of this tremendous progress in both accelerator science and technology is presented, with special emphasis on the new challenges of accelerator physics issues such as: H(-) injection, halo formation and reduction of losses.

  10. Beam instrumentation for future high intense hadron accelerators at Fermilab

    SciTech Connect

    Wendt, M.; Hu, M.; Tassotto, G.; Thurman-Keup, R.; Scarpine, V.; Shin, S.; Zagel, J.; /Fermilab

    2008-08-01

    High intensity hadron beams of up to 2 MW beam power are a key element of new proposed experimental facilities at Fermilab. Project X, which includes a SCRF 8 GeV H{sup -} linac, will be the centerpiece of future HEP activities in the neutrino sector. After a short overview of this, and other proposed projects, we present the current status of the beam instrumentation activities at Fermilab with a few examples. With upgrades and improvements they can meet the requirements of the new beam facilities, however design and development of new instruments is needed, as shown by the prototype and conceptual examples in the last section.

  11. Lead paint removal with high-intensity light pulses.

    PubMed

    Grapperhaus, Michael J; Schaefer, Raymond B

    2006-12-15

    This paper presents the results of an initial investigation into using high-intensity incoherent light pulses to strip paint. Measurements of light pulse characteristics, the reflectivity of different paints and initial experiments on the threshold for paint removal, and paint removal are presented, along with an approximate model consistent with experimental results. Paint removal tests include lead paint, the reduction of lead levels to below levels required for lead abatement, as well as air and light emissions measurements that are within regulatory guidelines.

  12. Fast damping in mismatched high intensity beam transportation

    NASA Astrophysics Data System (ADS)

    Variale, V.

    2001-08-01

    A very fast damping of beam envelope oscillation amplitudes was recently observed in simulations of high intensity beam transport, through periodic FODO cells, in mismatched conditions [V. Variale, Nuovo Cimento Soc. Ital. Fis. 112A, 1571-1582 (1999) and T. Clauser et al., in Proceedings of the Particle Accelerator Conference, New York, 1999 (IEEE, Piscataway, NJ, 1999), p. 1779]. A Landau damping mechanism was proposed at the origin of observed effect. In this paper, to further investigate the source of this fast damping, extensive simulations have been carried out. The results presented here support the interpretation of the mechanism at the origin of the fast damping as a Landau damping effect.

  13. ELECTRON COUD DYNAMICS IN HIGH-INTENSITY RINGS.

    SciTech Connect

    WANG, L.; WEI, J.

    2005-05-16

    Electron cloud due to beam-induced multipacting is one of the main concerns for the high intensity. Electrons generated and accumulated inside the beam pipe form an ''electron cloud'' that interacts with the circulating charged particle beam. With sizeable amount of electrons, this interaction can cause beam instability, beam loss and emittance growth. At the same time, the vacuum pressure will rise due to electron desorption. This talk intends to provide an overview of the mechanism and dynamics of the typical electron multipacting in various magnetic fields and mitigation measures with different beams.

  14. Can harms associated with high-intensity drinking be reduced by increasing the price of alcohol?

    PubMed

    Byrnes, Joshua; Shakeshaft, Anthony; Petrie, Dennis; Doran, Christopher

    2013-01-01

    Increasing the price of alcohol is consistently shown to reduce the average level of consumption. However, the evidence for the effect of increasing the price on high-intensity drinking is both limited and equivocal. The aim of this analysis is to estimate the effect of changes in price on patterns of consumption. Self-reported patterns of alcohol consumption and demographic data were obtained from the Australian National Drug Strategy Household Surveys, conducted in 2001, 2004 and 2007. A pooled three-stage least-squares estimator was used to simultaneously model the impact of the price on the frequency (measured in days) of consuming no, low, moderate and high quantities of alcohol. A 1% increase in the price of alcohol was associated with a statistically significant increase of 6.41 days per year on which no alcohol is consumed (P ≤ 0.049), and a statistically significant decrease of 7.30 days on which 1-4 standard drinks are consumed (P ≤ 0.021). There was no statistically significant change for high or moderate-intensity drinking. For Australia, and countries with a similar pattern of predominant high-intensity drinking, taxation policies that increase the price of alcohol and are very efficient at decreasing harms associated with reduced average consumption may be relatively inefficient at decreasing alcohol harms associated with high-intensity drinking. © 2012 Australasian Professional Society on Alcohol and other Drugs.

  15. Impact of Uncertainty from Load-Based Reserves and Renewables on Dispatch Costs and Emissions

    SciTech Connect

    Li, Bowen; Maroukis, Spencer D.; Lin, Yashen; Mathieu, Johanna L.

    2016-11-21

    Aggregations of controllable loads are considered to be a fast-responding, cost-efficient, and environmental-friendly candidate for power system ancillary services. Unlike conventional service providers, the potential capacity from the aggregation is highly affected by factors like ambient conditions and load usage patterns. Previous work modeled aggregations of controllable loads (such as air conditioners) as thermal batteries, which are capable of providing reserves but with uncertain capacity. A stochastic optimal power flow problem was formulated to manage this uncertainty, as well as uncertainty in renewable generation. In this paper, we explore how the types and levels of uncertainty, generation reserve costs, and controllable load capacity affect the dispatch solution, operational costs, and CO2 emissions. We also compare the results of two methods for solving the stochastic optimization problem, namely the probabilistically robust method and analytical reformulation assuming Gaussian distributions. Case studies are conducted on a modified IEEE 9-bus system with renewables, controllable loads, and congestion. We find that different types and levels of uncertainty have significant impacts on dispatch and emissions. More controllable loads and less conservative solution methodologies lead to lower costs and emissions.

  16. Oblique Loading in Post Mortem Human Surrogates from Vehicle Lateral Impact Tests using Chestbands.

    PubMed

    Yoganandan, Narayan; Humm, John R; Pintar, Frank A; Arun, Mike W J; Rhule, Heather; Rudd, Rodney; Craig, Matthew

    2015-11-01

    While numerous studies have been conducted to determine side impact responses of Post Mortem Human Surrogates (PMHS) using sled and other equipment, experiments using the biological surrogate in modern full-scale vehicles are not available. The present study investigated the presence of oblique loading in moving deformable barrier and pole tests. Threepoint belt restrained PMHS were positioned in the left front and left rear seats in the former and left front seat in the latter condition and tested according to consumer testing protocols. Three chestbands were used in each specimen (upper, middle and lower thorax). Accelerometers were secured to the skull, shoulder, upper, middle and lower thoracic vertebrae, sternum, and sacrum. Chestband signals were processed to determine magnitudes and angulations of peak deflections. The magnitude and timing of various signal peaks are given. Vehicle accelerations, door velocities, and seat belt loads are also given. Analysis of deformation contours, peak deflections, and angulations indicated that the left rear seated specimen were exposed to anterior oblique loading while left front specimens in both tests sustained essentially pure lateral loading to the torso. These data can be used to validate human body computational models. The occurrence of oblique loading in full-scale testing, hitherto unrecognized, may serve to stimulate the exploration of its role in injuries to the thorax and lower extremities in modern vehicles. It may be important to continue research in this area because injury metrics have a lower threshold for angled loading.

  17. Delaminations in composite plates under transverse static or impact loads - A model

    NASA Technical Reports Server (NTRS)

    Finn, Scott R.; Springer, George S.

    1993-01-01

    A method is presented for calculating the locations, shapes, and sizes of delaminations which occur in a fiber reinforced composite plate subjected to transverse static or dynamic (impact) loads. The plate may be simply supported, clamped, or free along its edges. A model of the delamination formation was developed. This model was then coupled with a finite element analysis. The model and the finite element analysis were implemented by a computer code which can be used to estimate the load at which damage is initiated as well as the locations, shapes, and sizes of the delaminations.

  18. The Impact of Boundary Conditions on Surface Curvature of Polypropylene Mesh in Response to Uniaxial Loading

    PubMed Central

    Barone, William R.; Amini, Rouzbeh; Maiti, Spandan; Moalli, Pamela A.; Abramowitch, Steven D.

    2015-01-01

    Exposure following pelvic organ prolapse repair has been observationally associated with wrinkling of the implanted mesh. The purpose of this study was to quantify the impact of variable boundary conditions on the out-of-plane deformations of mesh subjected to tensile loading. Using photogrammetry and surface curvature analyses, deformed geometries were accessed for two commercially available products. Relative to standard clamping methods, the amount of out-of-plane deformation significantly increased when point loads were introduced to simulate suture fixation in-vivo. These data support the hypothesis that regional increases in the concentration of mesh potentially enhance the host’s foreign body response, leading to exposure. PMID:25843260

  19. Reproductive costs for everyone: How female loads impact human mobility strategies

    PubMed Central

    Wall-Scheffler, Cara M.; Myers, Marcella J.

    2013-01-01

    While mobility strategies are considered important in understanding selection pressures on individuals, testing hypotheses of such strategies requires high resolution datasets, particularly at intersections between morphology, ecology and energetics. Here we present data on interactions between morphology and energetics in regards to the cost of walking for reproductive women and place these data into a specific ecological context of time and heat load. Frontal loads (up to 16% of body mass), as during pregnancy and child-carrying, significantly slow the optimal and preferred walking speed of women, significantly increase cost at the optimal speed, and make it significantly more costly for women to walk with other people. We further show for the first time significant changes in the curvature in the Cost of Transport curve for human walking, as driven by frontal loads. The impact of these frontal loads on females, and the populations to which they belong, would have been magnified by time constraints due to seasonal changes in day length at high latitudes and thermoregulatory limitations at low latitudes. However, wider pelves increase both stride length and speed flexibility, providing a morphological offset for load-related costs. Longer lower limbs also increase stride length. Observed differences between preferred and energetically optimal speeds with frontal loading suggest that speed choices of women carrying reproductive loads might be particularly sensitive to changes in heat load. Our findings show that female reproductive costs, particularly those related to locomotion, would have meaningfully shaped the mobility strategies of the hominin lineage, as well as modern foraging populations. PMID:23465336

  20. Physiological responses of young thoroughbred horses to intermittent high-intensity treadmill training

    PubMed Central

    2013-01-01

    Background Training of young Thoroughbred horses must balance development of cardiopulmonary function and aerobic capacity with loading of the musculoskeletal system that can potentially cause structural damage and/or lameness. High-speed equine treadmills are sometimes used to supplement exercise on a track in the training of young Thoroughbreds because the horse can run at high speeds but without the added weight of a rider. We tested the hypothesis that intermittent high-intensity exercise on a treadmill of young Thoroughbred horses entering training can enhance development of aerobic capacity (Vo2max) and running performance more than conventional training under saddle, and do so without causing lameness. Results Twelve yearling Thoroughbreds trained for 8 months with conventional riding (C) only, conventional riding plus a short (2 month, S) interval of once-per-week high-intensity treadmill exercise, or a long (8 month, L) interval of once-per-week high-intensity treadmill exercise. Three treadmill exercise tests evaluated Vo2max, oxygen transport and running performance variables in June of the yearling year (only for L), October of the yearling year and April of the 2-year-old year. No horses experienced lameness during the study. Aerobic capacity increased in all groups after training. In both October and April, Vo2max in L was higher than in C, but did not differ between L and S or S and C. Running speeds eliciting Vo2max also increased in all groups after training, with S (809 ± 3 m/s) and L (804 ± 9 m/s) higher than C (764 ± 27 m/s). Maximum heart rate decreased for all groups after training. Hematocrit and hemoglobin concentration increased for L throughout training. Conclusions Young Thoroughbred horses can increase aerobic capacity and running performance more than by strictly using track training under saddle with the addition of intermittent high-intensity treadmill exercise, and they can do so without experiencing lameness

  1. Computational Simulations of High Intensity X-Ray Matter Interaction

    SciTech Connect

    London, R A; Rionta, R; Tatchyn, R; Roessler, S

    2001-08-02

    Free electron lasers have the promise of producing extremely high-intensity short pulses of coherent, monochromatic radiation in the 1-10 keV energy range. For example, the Linac Coherent Light Source at Stanford is being designed to produce an output intensity of 2 x 10{sup 14} W/cm{sup 2} in a 230 fs pulse. These sources will open the door to many novel research studies. However, the intense x-ray pulses may damage the optical components necessary for studying and controlling the output. At the full output intensity, the dose to optical components at normal incidence ranges from 1-10 eV/atom for low-Z materials (Z < 14) at photon energies of 1 keV. It is important to have an understanding of the effects of such high doses in order to specify the composition, placement, and orientation of optical components, such as mirrors and monochromators. Doses of 10 eV/atom are certainly unacceptable since they will lead to ablation of the surface of the optical components. However, it is not precisely known what the damage thresholds are for the materials being considered for optical components for x-ray free electron lasers. In this paper, we present analytic estimates and computational simulations of the effects of high-intensity x-ray pulses on materials. We outline guidelines for the maximum dose to various materials and discuss implications for the design of optical components.

  2. Nanoplasma Formation by High Intensity Hard X-rays

    PubMed Central

    Tachibana, T.; Jurek, Z.; Fukuzawa, H.; Motomura, K.; Nagaya, K.; Wada, S.; Johnsson, P.; Siano, M.; Mondal, S.; Ito, Y.; Kimura, M.; Sakai, T.; Matsunami, K.; Hayashita, H.; Kajikawa, J.; Liu, X.-J.; Robert, E.; Miron, C.; Feifel, R.; Marangos, J. P.; Tono, K.; Inubushi, Y.; Yabashi, M.; Son, S.-K.; Ziaja, B.; Yao, M.; Santra, R.; Ueda, K.

    2015-01-01

    Using electron spectroscopy, we have investigated nanoplasma formation from noble gas clusters exposed to high-intensity hard-x-ray pulses at ~5 keV. Our experiment was carried out at the SPring-8 Angstrom Compact free electron LAser (SACLA) facility in Japan. Dedicated theoretical simulations were performed with the molecular dynamics tool XMDYN. We found that in this unprecedented wavelength regime nanoplasma formation is a highly indirect process. In the argon clusters investigated, nanoplasma is mainly formed through secondary electron cascading initiated by slow Auger electrons. Energy is distributed within the sample entirely through Auger processes and secondary electron cascading following photoabsorption, as in the hard x-ray regime there is no direct energy transfer from the field to the plasma. This plasma formation mechanism is specific to the hard-x-ray regime and may, thus, also be important for XFEL-based molecular imaging studies. In xenon clusters, photo- and Auger electrons contribute more significantly to the nanoplasma formation. Good agreement between experiment and simulations validates our modelling approach. This has wide-ranging implications for our ability to quantitatively predict the behavior of complex molecular systems irradiated by high-intensity hard x-rays. PMID:26077863

  3. CW high intensity non-scaling FFAG proton drivers

    SciTech Connect

    Johnstone, C.; Berz, M.; Makino, K.; Snopok, P.; /IIT, Chicago

    2011-04-01

    Accelerators are playing increasingly important roles in basic science, technology, and medicine including nuclear power, industrial irradiation, material science, and neutrino production. Proton and light-ion accelerators in particular have many research, energy and medical applications, providing one of the most effective treatments for many types of cancer. Ultra high-intensity and high-energy (GeV) proton drivers are a critical technology for accelerator-driven sub-critical reactors (ADS) and many HEP programs (Muon Collider). These high-intensity GeV-range proton drivers are particularly challenging, encountering duty cycle and space-charge limits in the synchrotron and machine size concerns in the weaker-focusing cyclotrons; a 10-20 MW proton driver is not presently considered technically achievable with conventional re-circulating accelerators. One, as-yet, unexplored re-circulating accelerator, the Fixed-field Alternating Gradient, or FFAG, is an attractive alternative to the cyclotron. Its strong focusing optics are expected to mitigate space charge effects, and a recent innovation in design has coupled stable tunes with isochronous orbits, making the FFAG capable of fixed-frequency, CW acceleration, as in the classical cyclotron. This paper reports on these new advances in FFAG accelerator technology and references advanced modeling tools for fixed-field accelerators developed for and unique to the code COSY INFINITY.

  4. Transcranial Clot Lysis Using High Intensity Focused Ultrasound

    NASA Astrophysics Data System (ADS)

    Hölscher, Thilo; Zadicario, Eyal; Fisher, David J.; Bradley, William G.

    2010-03-01

    Stroke is the third common cause of death worldwide. The majority of strokes are caused by sudden vessel occlusion, due to a blood clot. Vessel recanalization is the primary goal of all acute stroke treatment strategies. Initial data using ultrasound in combination with a therapeutic agent for clot lysis in stroke are promising. However, sound absorption and defocusing of the ultrasound beam occur during transskull insonation, limiting the efficiency of this approach to high extent. Using a transskull High Intensity Focused Ultrasound (HIFU) head system we were able to lyse blood clots within seconds and in absence of further lytic agents. We could show that any correction for the distortion might be negligible to focus the ultrasound beam after transskull insonation. The use of transskull HIFU for immediate clot lysis in the human brain without the need of further drugs and disregarding individual skull bone characteristics could become a successful strategy in early stroke treatment. Using magnetic resonance tomography for neuronavigation MRI Guided High Intensity Focused Ultrasound has the potential to open new avenues for therapeutic applications in the brain including Stroke, Intracranial Hemorrhages, Braintumors, Neurodegenerative Diseases, Thalamic Pain, BBB opening, and local drug delivery. First results in transcranial clot lysis will be presented in this paper.

  5. Free-field propagation of high intensity noise

    NASA Technical Reports Server (NTRS)

    Welz, Joseph P.; Mcdaniel, Oliver H.

    1990-01-01

    Observed spectral data from supersonic jet aircraft are known to contain much more high frequency energy than can be explained by linear acoustic propagation theory. It is believed that the high frequency energy is an effect of nonlinear distortion due to the extremely high acoustic levels generated by the jet engines. The objective, to measure acoustic waveform distortion for spherically diverging high intensity noise, was reached by using an electropneumatic acoustic source capable of generating sound pressure levels in the range of 140 to 160 decibels (re 20 micro Pa). The noise spectrum was shaped to represent the spectra generated by jet engines. Two microphones were used to capture the acoustic pressure waveform at different points along the propagation path in order to provide a direct measure of the waveform distortion as well as spectral distortion. A secondary objective was to determine that the observed distortion is an acoustic effect. To do this an existing computer prediction code that deals with nonlinear acoustic propagation was used on data representative of the measured data. The results clearly demonstrate that high intensity jet noise does shift the energy in the spectrum to the higher frequencies along the propagation path. In addition, the data from the computer model are in good agreement with the measurements, thus demonstrating that the waveform distortion can be accounted for with nonlinear acoustic theory.

  6. High Intensity X-Ray Coupling to Meteorite Targets

    NASA Astrophysics Data System (ADS)

    Remo, J. L.; Furnish, M. D.; Hammerling, P.

    2001-06-01

    The responses of iron-nickel and stony meteorite samples to high-intensity X-ray pulses (70 - 215 GW/cm^2) pulses generated by exploding wire array hohlraums from the Sandia Z machine are reported. Induced shock waves created particle velocities of 25 - 75 m/s after rarefaction overtake, as measured by VISAR. From these values both momentum and energy coupling coefficients were obtained. These results are compared to recent high-powered-pulsed ( 1 GW/cm2 for 20 ns) 1054 nm laser induced shock pressures and momentum transfer, and energy coupling to iron-rich and stony meteorite targets (J. L. Remo et al, Laser and Particle Beams, 17, 25-44, 1999). These comparisons provide data on the scaling of shock induced effects on inhomogeneous materials in general and meteoritic materials in particular. The combination of both of these experiments extends the regime of high intensity pulsed energy deposition on non-homogeneous materials from the GW/cm^2 to 100's of GW/cm^2, providing valuable empirical insights into the shock critical equations of state and coupling responses. Application to astrophysical and geophysical modeling will be discussed.

  7. Acoustic emission monitoring of low velocity impact damage in graphite/epoxy laminates during tensile loading

    NASA Technical Reports Server (NTRS)

    Parker, Bradford H.

    1992-01-01

    An acoustic emission (AE) system was set up in a linear location data acquisition mode to monitor the tensile loading of eight-ply quasi-isotropic graphite/epoxy specimens containing low velocity impact damage. The impact damage was induced using an instrumented drop weight tower. During impact, specimens were supported by either an aluminum plate or a membrane configuration. Cross-sectional examinations revealed that the aluminum plate configuration resulted in primarily matrix cracking and back surface fiber failure. The membrane support resulted in only matrix cracking and delamination damage. Penetrant enhanced radiography and immersion ultrasonics were used in order to assess the amount of impact damage in each tensile specimen. During tensile loading, AE reliably detected and located the damage sites which included fiber failure. All specimens with areas of fiber breakage ultimately failed at the impact site. AE did not reliably locate damage which consisted of only delaminations and matrix cracking. Specimens with this type of damage did not ultimately fail at the impact site. In summary, AE demonstrated the ability to increase the reliability of structural proof tests; however, the successful use of this technique requires extensive baseline testing.

  8. Methodology for mapping football head impact exposure to helmet pads for repeated loading testing.

    PubMed

    MacAlister, Anna; Young, Tyler; Daniel, Ray W; Rowson, Steven; Duma, Stefan M

    2014-01-01

    Football helmets have a lifespan of 10 years; however, no work has investigated how helmet padding properties change over time with use. The purpose of this study is to develop a methodology to control repeated pad loading and quantify changes in energy management. Head impact exposure data for 7-8 year old football players were used to find an average impact magnitude. NOCSAE-style drop tests were performed using an instrumented headform fitted with the same style helmet (Helmet A) used to collect population data to determine the compression depth and rate of the helmet padding during an average impact. Drops from the same height were then conducted for two other helmet types (Helmet B and Helmet C). For the average impact of ~15 g, the compression depth and rate of the pads from Helmet A were found to be 9.8 mm and 0.72 m/s respectively. The compression depths and rates for Helmets B and C were found to be 6.1 mm and 0.71 m/s and 10.7 mm and 0.69 m/s respectively. These parameters were utilized by a material testing system program to impact helmet padding. Repeated helmet pad loading can be tested using a material testing system for populations with known head impact exposure. The energy absorbing characteristics of the padding can be used to develop new safety regulations regarding the lifetime of helmets, affording better protection to athletes.

  9. Limitations of power conversion systems under transient loads and impact on the pulsed tokamak power reactor

    NASA Astrophysics Data System (ADS)

    Sager, G. T.; Wong, C. P. C.; Kapich, D. D.; McDonald, C. F.; Schleicher, R. W.

    1993-11-01

    The impact of cyclic loading of the power conversion system of a helium-cooled, pulsed tokamak power plant is assessed. Design limits of key components of heat transport systems employing Rankine and Brayton thermodynamic cycles are quantified based on experience in gas-cooled fission reactor design and operation. Cyclic loads due to pulsed tokamak operation are estimated. Expected performance of the steam generator is shown to be incompatible with pulsed tokamak operation without load leveling thermal energy storage. The close cycle gas turbine is evaluated qualitatively based on performance of existing industrial and aeroderivative gas turbines. Advances in key technologies which significantly improve prospects for operation with tokamak fusion plants are reviewed.

  10. Limitations of power conversion systems under transient loads and impact on the pulsed tokamak power reactor

    SciTech Connect

    Sager, G.T.; Wong, C.P.C.; Kapich, D.D.; McDonald, C.F.; Schleicher, R.W.

    1993-11-01

    The impact of cyclic loading of the power conversion system of a helium-cooled, pulsed tokamak power plant is assessed. Design limits of key components of heat transport systems employing Rankie and Brayton thermodynamic cycles are quantified based on experience in gas-cooled fission reactor design and operation. Cyclic loads due to pulsed tokamak operation are estimated. Expected performance of the steam generator is shown to be incompatible with pulsed tokamak operation without load leveling thermal energy storage. The close cycle gas turbine is evaluated qualitatively based on performance of existing industrial and aeroderivative gas turbines. Advances in key technologies which significantly improve prospects for operation with tokamak fusion plants are reviewed.

  11. Reducing impact loading during running with the use of real-time visual feedback.

    PubMed

    Crowell, Harrison Philip; Milner, Clare E; Hamill, Joseph; Davis, Irene S

    2010-04-01

    Single-subject with repeated measures. To determine if runners can use real-time visual feedback from an accelerometer to achieve immediate reductions in tibial acceleration and vertical-force loading rates. Stress fractures are a common injury among runners. Previous studies suggest that runners with higher than normal tibial acceleration and vertical-force loading rates are at increased risk for tibial stress fractures. If these runners can be trained to reduce the loading on their lower extremities, it may reduce their risk of stress fractures. Five subjects participated in this study. All subjects ran on a treadmill, instrumented with force transducers, during a single 30-minute session that was divided into warm-up, feedback, no-feedback, and cool-down periods. During running, the subjects also wore an accelerometer taped to their distal right tibia. Peak positive acceleration of the tibia, vertical force impact peak, and average and instantaneous vertical-force loading rates were assessed at the end of the warm-up, feedback, and no-feedback periods. Single-subject analysis revealed that 4 of the 5 subjects had significant reductions in their peak positive acceleration at the end of the no-feedback period compared to the warm-up. In addition, all of the subjects had significant decreases in impact peak and vertical ground reaction force loading rates at the end of the no-feedback period. In a single session of training with real-time visual feedback, it appears that most runners can reduce the types of lower extremity loading associated with stress fractures. This may lead to training programs that reduce the risk of stress fractures for runners.

  12. High-intensity focused ultrasound plus concomitant radiotherapy: a new weapon in oncology?

    PubMed Central

    2013-01-01

    The potential impact of high-intensity focused ultrasound (HIFU) to general medicine and oncology seems very high. However, while in the research area, the development of this technique is very rapid and unchallenged. The direct application of HIFU to human tumour therapy is hampered by various technical difficulties, which may confine its role to a marginal device in the surgery armamentarium. To deploy the full potential of focused ultrasound in oncology, it seems necessary to review the basic relationship between HIFU and external beam radiotherapy. This is the aim of the present work. PMID:24761227

  13. Impact of Frequency of Load Changes in Fatigue Tests on the Temperature of the Modified Polymer

    NASA Astrophysics Data System (ADS)

    Komorek, Andrzej; Komorek, Zenon; Krzyzak, Aneta; Przybylek, Pawel; Szczepaniak, Robert

    2017-08-01

    In the article, the authors describe the analysis of the impact of the frequency of fatigue tests on the temperature of the modified polymer. The base material for producing the samples was the epoxy resin Epidian 57 cured with Z1 hardener. The presented study is part of a research program of adhesive joints made with the composition Epidian 57/Z1 aiming to determine the effect of physical modification of the adhesive composition on its properties and on the properties of adhesive joints made with such a modified composition. The tested adhesive compositions were modified by additions of micro- and nanoparticles in an amount of 1.85 % (micro- and nanoparticles) or 10 % (microparticles) in weight, depending on the type of the particles. In the studies, the authors used the particles of tungsten, microspheres and carbon nanotubes. The polymer samples produced by casting were loaded with compressive identical, one-sided loads at two different frequencies of load changes. During the tests, the authors recorded the temperature changes as a function of the number of cycles. The changes in the temperature field on the surface of the samples during the tests were observed by the infrared camera. As a result of the studies, it was possible to observe a significant impact of the composition of the polymer and the frequency of load changes during the test on the temperature of the sample.

  14. Space Shuttle solid rocket booster initial water impact loads and dynamics - Analysis, tests, and flight experience

    NASA Technical Reports Server (NTRS)

    Kross, D. A.; Kiefling, L. A.; Murphy, N. C.; Rawls, E. A.

    1983-01-01

    A series of scale model tests, finite element dynamic response analyses and full scale segment tests have been performed for purposes of developing design criteria for the initial water impact loading conditions applied to the internal stiffener rings located in the aft skirt portion of the Space Shuttle Solid Rocket Booster (SRB). In addition, flight experience has yielded information relative to structural reinforcement requirements. This paper discusses the test and analysis methods and summarizes significant results. It is noted that, although scale model test data are valuable for identifying trends, they have shortcomings concerning definition of full scale design loads criteria. Also, the frequently used static equivalent loads definition approach is not applicable for this type impact loading condition applied to an aft skirt type structure. Various types of ring structural fixes, including the addition of selected types of foam, are presented as well as associated full scale segment test results. Depending on the type and contour shape of the foam, reductions on applied pressures and peak measured strains over 50 percent are noted.

  15. Impact of Filtration Velocities and Particulate Matter Characteristics on Diesel Particulate Filter Wall Loading Performance

    SciTech Connect

    Lance, Michael J; Walker, Larry R; Yapaulo, Renato A; Orita, Tetsuo; Wirojsakunchai, Ekathai; Foster, David; Akard, Michael

    2009-01-01

    The impact of different types of diesel particulate matter (PM) and different sampling conditions on the wall deposition and early soot cake build up within diesel particulate filters has been investigated. The measurements were made possible by a newly developed Diesel Exhaust Filtration Analysis (DEFA) system in which in-situ diesel exhaust filtration can be reproduced with in small cordierite wafer disks, which are essentially thin sections of a Diesel Particulate Filter (DPF) wall. The different types of PM were generated from selected engine operating conditions of a single-cylinder heavy-duty diesel engine. Two filtration velocities 4 and 8 cm/s were used to investigate PM deep-bed filtration processes. The loaded wafers were then analyzed in a thermal mass analyzer that measures the Soluble Organic Fraction (SOF) as well as soot and sulfate fractions of the PM. In addition, the soot residing in the wall of the wafer was examined under an optical microscope illuminated with Ultraviolet light and an Environmental Scanning Electron Microscope (E-SEM) to determine the bulk soot penetration depth for each loading condition. It was found that higher filtration velocity results in higher wall loading with approximately the same penetration depth into the wall. PM characteristics impacted both wall loading and soot cake layer characteristics. Results from imaging analysis indicate that soot the penetration depth into the wall was affected more by PM size (which changes with engine operating conditions) rather than filtration velocity.

  16. Numerical modeling of polyurea coated cementitious materials for flexure and impact loads

    NASA Astrophysics Data System (ADS)

    Pothula, Naga Deepika

    The research focuses on predicting the mechanical properties of various cementitious based materials coated with polyurea using the finite element program ABAQUS. To determine the effect of the polyurea coated systems, simple finite element analyses are performed on the beam model for flexure and the concrete slab model for impact. The experimental results carried out by Hyungjoo Choi [1, 2] are used to validate the model and to study the effect of the coating conditions of polyurea (plain, top, bottom, both). The load-displacement curves are plotted. Results show that using polyurea coating increases of deflection and load at failure (ductility), ultimate strength and strain, of Poly (Vinyl Butyral) (PVB) and Poly (Vinyl Alcohol) (PVA) fiber reinforced specimens. The simulation response for various models matched the experimental results very closely. Impact models depict the stresses developed and show that applying polyurea coating on the bottom seems to produce the best results.

  17. Damage Simulation in Non-Crimp Fabric Composite Plates Subjected to Impact Loads

    NASA Technical Reports Server (NTRS)

    Satyanarayana, Arunkumar; Bogert, Philip B.; Aitharaju, Venkat; Aashat, Satvir; Kia, Hamid

    2014-01-01

    Progressive failure analysis (PFA) of non-crimp fabric (NCF) composite laminates subjected to low velocity impact loads was performed using the COmplete STress Reduction (COSTR) damage model implemented through VUMAT and UMAT41 user subroutines in the frame works of the commercial finite element programs ABAQUS/Explicit and LS-DYNA, respectively. To validate the model, low velocity experiments were conducted and detailed correlations between the predictions and measurements for both intra-laminar and inter-laminar failures were made. The developed material and damage model predicts the peak impact load and duration very close with the experimental results. Also, the simulation results of delamination damage between the ply interfaces, in-plane matrix damages and fiber damages were all in good agreement with the measurements from the non-destructive evaluation data.

  18. Mechanical response of a fibre reinforced earthen material under static and impact loadings

    NASA Astrophysics Data System (ADS)

    Aymerich, Francesco; Fenu, Luigi; Francesconi, Luca; Meloni, Paola

    2015-09-01

    This study examines the improvements provided by the insertion of hemp fibres with different weight fractions and lengths in an earthen material. The structural response of the materials was investigated by means of static and impact bending tests carried out on notched samples. The main focus of the analyses was in the characterization of the structural properties of the materials in terms of fracture resistance, post-cracking performance and energy absorption capability. The results of the study show that hemp fibres improve significantly the mechanical and fracture properties of the earthen material under both static and dynamic bending. It was also found that the structural properties of unreinforced and reinforced earthen materials are highly sensitive to the stress-rate, with higher strength and fracture resistance under impact loading than under static loading.

  19. Diet composition and the performance of high-intensity exercise.

    PubMed

    Maughan, R J; Greenhaff, P L; Leiper, J B; Ball, D; Lambert, C P; Gleeson, M

    1997-06-01

    The crucial role of muscle glycogen as a fuel during prolonged exercise is well established, and the effects of acute changes in dietary carbohydrate intake on muscle glycogen content and on endurance capacity are equally well known. More recently, it has been recognized that diet can also affect the performance of high-intensity exercise of short (2-7 min) duration. If the muscle glycogen content is lowered by prolonged (1-1.5 h) exhausting cycle exercise, and is subsequently kept low for 3-4 days by consumption of a diet deficient in carbohydrate (< 5% of total energy intake), there is a dramatic (approximately 10-30%) reduction in exercise capacity during cycling sustainable for about 5 min. The same effect is observed if exercise is preceded by 3-4 days on a carbohydrate-restricted diet or by a 24 h total fast without prior depletion of the muscle glycogen. Consumption of a diet high in carbohydrate (70% of total energy intake from carbohydrate) for 3-4 days before exercise improves exercise capacity during high-intensity exercise, although this effect is less consistent. The blood lactate concentration is always lower at the point of fatigue after a diet low in carbohydrate and higher after a diet high in carbohydrate than after a normal diet. Even when the duration of the exercise task is kept constant, the blood lactate concentration is higher after exercise on a diet high in carbohydrate than on a diet low in carbohydrate. Consumption of a low-carbohydrate isoenergetic diet is achieved by an increased intake of protein and fat. A high-protein diet, particularly when combined with a low carbohydrate intake, results in metabolic acidosis, which ensues within 24 h and persists for at least 4 days. This appears to be the result of an increase in the circulating concentrations of strong organic acids, particularly free fatty acids and 3-hydroxybutyrate, together with an increase in the total plasma protein concentration. This acidosis, rather than any decrease

  20. High-Intensity Sweeteners in Alternative Tobacco Products

    PubMed Central

    Miao, Shida; Beach, Evan S.; Sommer, Toby J.; Zimmerman, Julie B.

    2016-01-01

    Introduction: Sweeteners in tobacco products may influence use initiation and reinforcement, with special appeal to adolescents. Recent analytical studies of smokeless tobacco products (snuff, snus, dissolvables) detected flavorants identical to those added to confectionary products such as hard candy and chewing gum. However, these studies did not determine the levels of sweeteners. The objective of the present study was to quantify added sweeteners in smokeless tobacco products, a dissolvable product, electronic cigarette liquids and to compare with sweetener levels in confectionary products. Methods: Sweetener content of US-sourced smokeless tobacco, electronic cigarette liquid, and confectionary product samples was analyzed by liquid chromatography-electrospray ionization–mass spectrometry (LC-ESI-MS). Results: All smokeless products contained synthetic high intensity sweeteners, with snus and dissolvables exceeding levels in confectionary products (as much as 25-fold). All snus samples contained sucralose and most also aspartame, but no saccharin. In contrast, all moist snuff samples contained saccharin. The dissolvable sample contained sucralose and sorbitol. Ethyl maltol was the most common sweet-associated component in electronic cigarette liquids. Discussion: Sweetener content was dependent on product category, with saccharin in moist snuff, an older category, sucralose added at high levels to more recently introduced products (snus, dissolvable) and ethyl maltol in electronic cigarette liquid. The very high sweetener concentrations may be necessary for the consumer to tolerate the otherwise aversive flavors of tobacco ingredients. Regulation of sweetener levels in smokeless tobacco products may be an effective measure to modify product attractiveness, initiation and use patterns. Implications: Dissolvables, snus and electronic cigarettes have been promoted as risk-mitigation products due to their relatively low content of nitrosamines and other tobacco

  1. High-Intensity Sweeteners in Alternative Tobacco Products.

    PubMed

    Miao, Shida; Beach, Evan S; Sommer, Toby J; Zimmerman, Julie B; Jordt, Sven-Eric

    2016-11-01

    Sweeteners in tobacco products may influence use initiation and reinforcement, with special appeal to adolescents. Recent analytical studies of smokeless tobacco products (snuff, snus, dissolvables) detected flavorants identical to those added to confectionary products such as hard candy and chewing gum. However, these studies did not determine the levels of sweeteners. The objective of the present study was to quantify added sweeteners in smokeless tobacco products, a dissolvable product, electronic cigarette liquids and to compare with sweetener levels in confectionary products. Sweetener content of US-sourced smokeless tobacco, electronic cigarette liquid, and confectionary product samples was analyzed by liquid chromatography-electrospray ionization-mass spectrometry (LC-ESI-MS). All smokeless products contained synthetic high intensity sweeteners, with snus and dissolvables exceeding levels in confectionary products (as much as 25-fold). All snus samples contained sucralose and most also aspartame, but no saccharin. In contrast, all moist snuff samples contained saccharin. The dissolvable sample contained sucralose and sorbitol. Ethyl maltol was the most common sweet-associated component in electronic cigarette liquids. Sweetener content was dependent on product category, with saccharin in moist snuff, an older category, sucralose added at high levels to more recently introduced products (snus, dissolvable) and ethyl maltol in electronic cigarette liquid. The very high sweetener concentrations may be necessary for the consumer to tolerate the otherwise aversive flavors of tobacco ingredients. Regulation of sweetener levels in smokeless tobacco products may be an effective measure to modify product attractiveness, initiation and use patterns. Dissolvables, snus and electronic cigarettes have been promoted as risk-mitigation products due to their relatively low content of nitrosamines and other tobacco toxicants. This study is the first to quantify high

  2. A Generalized Hydrodynamic-Impact Theory for the Loads and Motions of Deeply Immersed Prismatic Bodies

    NASA Technical Reports Server (NTRS)

    Markey, Melvin F.

    1959-01-01

    A theory is derived for determining the loads and motions of a deeply immersed prismatic body. The method makes use of a two-dimensional water-mass variation and an aspect-ratio correction for three-dimensional flow. The equations of motion are generalized by using a mean value of the aspect-ratio correction and by assuming a variation of the two-dimensional water mass for the deeply immersed body. These equations lead to impact coefficients that depend on an approach parameter which, in turn, depends upon the initial trim and flight-path angles. Comparison of experiment with theory is shown at maximum load and maximum penetration for the flat-bottom (0 deg dead-rise angle) model with bean-loading coefficients from 36.5 to 133.7 over a wide range of initial conditions. A dead-rise angle correction is applied and maximum-load data are compared with theory for the case of a model with 300 dead-rise angle and beam-loading coefficients from 208 to 530.

  3. Impact of pore characteristics of silica materials on loading capacity and release behavior of ibuprofen.

    PubMed

    Numpilai, Thanapha; Muenmee, Suthaporn; Witoon, Thongthai

    2016-02-01

    Impact of pore characteristics of porous silica supports on loading capacity and release behavior of ibuprofen was investigated. The porous silica materials and ibuprofen-loaded porous silica materials were thoroughly characterized by N2-sorption, thermal gravimetric and derivative weight analyses (TG-DTW), X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FT-IR), scanning electron microscope (SEM), transmission electron microscope (TEM) to determine the physical properties of materials, amount of ibuprofen adsorbed and position of ibuprofen. The detailed characterization reveals that the ibuprofen molecules adsorbed inside the mesopores. Increasing the mesopore size from 5nm to 10nm increased the ibuprofen loading from 0.74 to 0.85mmol/g, respectively. Incorporation of macropore into the structure of porous silica materials enhanced the ibuprofen loading capacity of 11.8-20.3%. The ibuprofen-loaded bimodal meso-macroporous silica materials exhibited the highest dissolution of 92wt.% within an hour. The ibuprofen particles deposited on the external surface of the porous silica materials showed a lower dissolution rate than the ibuprofen adsorbed inside the mesopores due to the formation of ibuprofen crystalline.

  4. Impact of Generalized Joint Laxity on Plantar Loading Patterns in Young Females.

    PubMed

    Aydın, Elif; Metin Tellioğlu, Ayfer; Kurt Ömürlü, Imran; Turan, Yasemin

    2017-08-01

    Generalized joint laxity is often associated with gait deviations. The aim of this study was to investigate the static and dynamic loading pattern of the foot with increasing joint mobility and to discuss the potential impact of this condition on the plantar loading patterns. Seventy female participants between ages of 18 and 30 were included in this cross-sectional survey. The Beighton-Horan Joint Mobility Index scores were assessed and participants divided into 3 categories: no hypermobility (NH) group, scores 0 to 2; moderate hypermobility (MH) group, scores 3 to 4; distinct hypermobility (DH) group, scores 5 to 9. Pedobarographic analysis was performed both in static and walking conditions. Dynamic foot loading examined in 10 anatomic zones. Contact areas of forefoot, midfoot, and rearfoot were recorded. In the dynamic pedobarographic analysis, individuals with distinct joint hypermobility displayed higher peak pressure and maximum force values under the hallux, compared with other groups ( P < .05). The maximum force value of the second metatarsal was higher in the DH group than in the MH group ( P < .05). Our study results suggest that plantar loading pattern differs with increasing degrees of the hypermobility score. Differences in plantar loading parameters in people with severe joint mobility scores may be useful in interpreting the foot pathologies of these individuals.

  5. Modeling the impact of scaffold architecture and mechanical loading on collagen turnover in engineered cardiovascular tissues.

    PubMed

    Argento, G; de Jonge, N; Söntjens, S H M; Oomens, C W J; Bouten, C V C; Baaijens, F P T

    2015-06-01

    The anisotropic collagen architecture of an engineered cardiovascular tissue has a major impact on its in vivo mechanical performance. This evolving collagen architecture is determined by initial scaffold microstructure and mechanical loading. Here, we developed and validated a theoretical and computational microscale model to quantitatively understand the interplay between scaffold architecture and mechanical loading on collagen synthesis and degradation. Using input from experimental studies, we hypothesize that both the microstructure of the scaffold and the loading conditions influence collagen turnover. The evaluation of the mechanical and topological properties of in vitro engineered constructs reveals that the formation of extracellular matrix layers on top of the scaffold surface influences the mechanical anisotropy on the construct. Results show that the microscale model can successfully capture the collagen arrangement between the fibers of an electrospun scaffold under static and cyclic loading conditions. Contact guidance by the scaffold, and not applied load, dominates the collagen architecture. Therefore, when the collagen grows inside the pores of the scaffold, pronounced scaffold anisotropy guarantees the development of a construct that mimics the mechanical anisotropy of the native cardiovascular tissue.

  6. Impacts of reservoirs on the streamflow and sediment load of the Hanjiang River, China.

    PubMed

    Qian, Bao; Zhang, Debing; Wang, Jincheng; Huang, Feng; Wu, Yao

    2016-11-01

    The Hanjiang River is an important tributary of the Yangtze River in China. Long-term observed streamflow and sediment load data that spanned 1951-2014 was collected from the Huangzhuang hydrometric station, which is located at the middle reaches. The data was analyzed to reveal the impacts of reservoirs on streamflow and sediment load of the Hanjiang River. The coefficient of variation (C v) and concentration degree (C d) were applied to describe the intra-annual distribution characteristics. Abrupt changes in the time series of the streamflow and sediment load were detected by the heuristic segmentation algorithm. The annual streamflow significantly decreased from 1561 to 1263 m(3)/s after 1991, which was mainly caused by climate change. Two significant change points in the annual sediment load series occurred at 1966 and 1985, and the average values of the sub-series were 3198, 952, and 251 kg/s, respectively. Significant change points in the C v and C d series of the streamflow and sediment load occurred around 1967. The C v and C d series decreased dramatically after the change points. Abrupt changes in the time series of the streamflow and sediment load mainly occurred around 1967 when the Danjiangkou reservoir began to impound water, indicating that the Danjiangkou reservoir was an important factor that caused hydrological changes. The reservoir trapped sediment, reduced sediment concentration, mitigated the monthly streamflow and sediment load fluctuations, and reduced the intra-annual variation and concentration. Assessed by the range of variability approaches, the overall alteration degrees of the streamflow and sediment regimes were 36 and 60 %, respectively, which qualified as a moderate degree. The reservoir exerted greater influence on the sediment regime than on the streamflow regime.

  7. Strain Rate Effects for Concrete and Fiber Reinforced Concrete Subjected to Impact Loading

    DTIC Science & Technology

    1987-10-01

    S. Mindess and S. P. Shah) MRS Symposia Proceedings, V67. 64, pp. 21-37, 1986. 9. Shah, S. P., "Concrete and Fiber Reinforced Concrete Subjected to...Impact Loading," in Cement Based Composites: Strain Rate Effects on Fracture (eds. S. Mindess and S. P. Shah) MRS Symposia Proceedings, Vol. 64, pp... Mindess (11), Sierakowski (12), aAd Reinhardt (13). Many investigators (see for example Ref. 6) have studied the rate sensitivity of fracture strength

  8. Impacts of reforestation upon sediment load and water outflow in the Lower Yazoo River Watershed, Mississippi

    Treesearch

    Ying Ouyang; Theodor D. Leininger; Matt Moran

    2013-01-01

    Among the world’s largest coastal and river basins, the Lower Mississippi River Alluvial Valley (LMRAV)is one of the most disturbed by human activities. This study ascertained the impacts of reforestation on water outflow attenuation (i.e., water flow out of the watershed outlet) and sediment load reduction in the Lower Yazoo River Watershed (LYRW) within the LMRAV...

  9. Effects of high-intensity running training on soccer-specific fitness in professional male players.

    PubMed

    Wells, Carl; Edwards, Andrew; Fysh, Mary; Drust, Barry

    2014-07-01

    The purpose of this study was to investigate whether or not physiological and performance gains could be achieved with the addition of high-intensity running to an existing training programme in a group of well trained professional male soccer players. Sixteen professional male players (21.3 ± 2.1 years, stature 177.4 ± 4.2 cm, body mass 73.1 ± 8.1 kg) were randomised in training (TRA, n = 8) and control (CON, n = 8) groups. All players performed physiological assessments before and after a 6-week intervention. Outcome measures were: (i) V̇O2peak, (ii) V̇O2 kinetics during very heavy-intensity exercise, (iii) a maximal anaerobic running test, and (iv) Yo-Yo Intermittent Recovery Test level 2 (YIRT2). The only aerobic parameter to change after the intervention was the phase III time constant at exercise onset for CON, which lengthened (p = 0.012) to a value similar to that of the TRA group. However, TRA showed gains in anaerobic performance (p = 0.021), time to exhaustion (p = 0.019), and maximal running speed (p = 0.023). In the YIRT2, distance run increased for TRA over time (p = 0.015), and the TRA group were also capable of running further in the YIRT2 after the intervention compared with CON (p = 0.011). This study shows it is possible to improve the soccer-specific high-intensity running capacity of professional players when high-intensity intermittent training is added to the normal training load and that this effect is only detectable in anaerobic capabilities. The observed effects are meaningful to the training practices of elite athletes seeking a competitive edge in team sports when otherwise well matched.

  10. Absence of Respiratory Muscle Fatigue in High-Intensity Continuous or Interval Cycling Exercise.

    PubMed

    Kurti, Stephanie P; Smith, Joshua R; Emerson, Sam R; Castinado, Kenneth M; Harms, Craig A

    2015-11-01

    Respiratory muscle fatigue (RMF) occurs during prolonged exercise (∼15-20 minutes) at >85% V[Combining Dot Above]O2max. However, RMF has been reported to occur in ∼3-6 minutes in various modes of exercise at a high intensity. It is not known if continuous cycling exercise vs. repeated bouts of high-intensity interval training (HIT) at >85% V[Combining Dot Above]O2max will lead to RMF. We hypothesized that RMF would occur after a constant load test and would be present before end exercise in an HIT protocol. Eight moderately active healthy men (21.7 ± 1.7 years; 181.3 ± 5.2 cm; 81.3 ± 2.3 kg) completed a V[Combining Dot Above]O2max test on a cycle ergometer. Subjects then completed 2 bouts of HIT (7 × 1 minute, 2-minute recovery between intervals) and 3 bouts of continuous exercise (CE) tests at 90% of peak power (determined from an incremental exercise test to exhaustion). Maximal inspiratory pressure (PIMAX) and expiratory pressure (PEMAX) were measured pre- and post-exercise for both HIT and CE and after each interval during HIT. Decreases in postexercise PIMAX and PEMAX compared with baseline were used to determine RMF. There were no differences (p > 0.05) in PIMAX or PEMAX pre- to post-exercise for HIT (PIMAX pre: 134 ± 51, post: 135 ± 50 cmH2O; PEMAX pre: 143 ± 41, post: 148 ± 46 cmH2O) or CE (PIMAX pre: 135 ± 54, post: 133 ± 52 cmH2O; PEMAX pre: 146 ± 46, post: 148 ± 46 cmH2O) indicating RMF was not present following CE and HIT. These data suggest that repeated high-intensity cycling exercise at 90% peak power in a CE or HIT protocol does not lead to RMF.

  11. Effect of caffeine ingestion after creatine supplementation on intermittent high-intensity sprint performance.

    PubMed

    Lee, Chia-Lun; Lin, Jung-Charng; Cheng, Ching-Feng

    2011-08-01

    The aim of this study was to investigate the effects of acute caffeine ingestion on intermittent high-intensity sprint performance after 5 days of creatine loading. After completing a control trial (no ergogenic aids, CON), twelve physically active men were administered in a double-blind, randomized crossover protocol to receive CRE + PLA (0.3 g kg(-1) day(-1) of creatine for 5 days then followed by 6 mg kg(-1) of placebo) and CRE + CAF (0.3 g kg(-1) day(-1) of creatine for 5 days and followed by 6 mg kg(-1) of caffeine), after which they performed a repeated sprint test. Each test consisted of six 10-s intermittent high-intensity sprints on a cycling ergometer, with 60-s rest intervals between sprints. Mean power, peak power, rating of perceived exertion (RPE), and heart rates were measured during the test. Blood samples for lactate, glucose, and catecholamine concentrations were drawn at specified intervals. The mean and peak power observed in the CRE + CAF were significantly higher than those found in the CON during Sprints 1 and 3; and the CRE + CAF showed significantly higher mean and peak power than that in the CRE + PLA during Sprints 1 and 2. The mean and peak power during Sprint 3 in the CRE + PLA was significantly greater than that in the CON. Heart rates, plasma lactate, and glucose increased significantly with CRE + CAF during most sprints. No significant differences were observed in the RPE among the three trials. The present study determined that caffeine ingestion after creatine supplements augmented intermittent high-intensity sprint performance.

  12. Effects of high-intensity interval training on the VO2 response during severe exercise.

    PubMed

    Duffield, Rob; Edge, Johann; Bishop, David

    2006-06-01

    This study examined the effect of high-intensity interval training on the VO2 response during severe, constant-load exercise. Prior to, and following training, 10 females (V O2 peak 37.4+/-6.0 mL kg-1 min-1) performed a graded exercise test to determine VO2 peak and lactate threshold (LT) and a 6 min cycle test (CT) at the pre-training VO2 peak intensity. Training involved high-intensity intervals (2 min work, 1 min rest) performed 3x week for 8 weeks. Breath-by-breath data from 0 to 6 min during the CT were smoothed using 5s averages and fit to a bi-exponential model starting from 20s. Training resulted in significant improvements in VO2 max (2.34+/-0.37-2.78+/-0.30 L min-1), power at VO2 max (170+/-26-204+/-25 W) and power at LT (113+/-17-136+/-20 W) (p<0.05). Following training, the VO2 response showed a significant increase in the amplitude of the primary phase (A1) (1396+/-103-1695+/-100 mL min-1; p<0.05) and end-exercise VO2 (VO2 EE), with no difference (p>0.05) in the time constants of either phase or the amplitude of the slow component (318+/-67-380+/-48 mL; p=0.15). In conjunction, accumulated oxygen deficit (AOD) (43.7+/-9.8-17.2+/-2.8 mL O2 eq kg-1) and anaerobic contribution to the CT (19.4+/-4.4-7.2+/-1.2%) were significantly reduced. In contrast to previous moderate-intensity research, a high-intensity interval training program increased A1 and VO2 EE for the same absolute exercise intensity, decreasing the AOD during a severe-intensity CT.

  13. High-Intensity Focused Ultrasound Treatment for Advanced Pancreatic Cancer

    PubMed Central

    Zhou, Yufeng

    2014-01-01

    Pancreatic cancer is under high mortality but has few effective treatment modalities. High-intensity focused ultrasound (HIFU) is becoming an emerging approach of noninvasively ablating solid tumor in clinics. A variety of solid tumors have been tried on thousands of patients in the last fifteen years with great success. The principle, mechanism, and clinical outcome of HIFU were introduced first. All 3022 clinical cases of HIFU treatment for the advanced pancreatic cancer alone or in combination with chemotherapy or radiotherapy in 241 published papers were reviewed and summarized for its efficacy, pain relief, clinical benefit rate, survival, Karnofsky performance scale (KPS) score, changes in tumor size, occurrence of echogenicity, serum level, diagnostic assessment of outcome, and associated complications. Immune response induced by HIFU ablation may become an effective way of cancer treatment. Comments for a better outcome and current challenges of HIFU technology are also covered. PMID:25053938

  14. Optimal conditions for tissue perforation using high intensity focused ultrasound

    NASA Astrophysics Data System (ADS)

    Mochizuki, Takashi; Kihara, Taizo; Ogawa, Kouji; Tanabe, Ryoko; Yosizawa, Shin; Umemura, Shin-ichiro; Kakimoto, Takashi; Yamashita, Hiromasa; Chiba, Toshio

    2012-10-01

    To perforate tissue lying deep part in body, a large size transducer was assembled by combining four spherical-shaped transducers, and the optimal conditions for tissue perforation have studied using ventricle muscle of chicken as a target. The ex vivo experiments showed that ventricle muscle was successfully perforated both when it was exposed to High Intensity Focused Ultrasound (HIFU) directly and when it was exposed to HIFU through atrial muscle layer. Moreover, it was shown that calculated acoustic power distributions are well similar to the perforation patterns, and that the acoustic energy distributes very complexly near the focus. Lastly, perforation on the living rabbit bladder wall was demonstrated as a preliminary in vivo experiment.

  15. High-intensity laser-induced electron acceleration in vacuum.

    PubMed

    Wang, J X; Ho, Y K; Feng, L; Kong, Q; Wang, P X; Yuan, Z S; Scheid, W

    1999-12-01

    In this paper, an approximate pulsed-laser-beam solution of Maxwell's equation in vacuum is derived. Then with the numerical simulation method, electron acceleration induced by high-intensity [Q(0)=eE(0)/(m(e)omega c)=3] lasers is discussed in connection with the recent experiment of Malka et al. It is found that the maximum energy gain and the relationship between the final energy and the scattering angle can be well reproduced, but the polarization effect of electron-laser interactions is not very prominent. These results show that the ponderomotive potential model is still applicable, which means that the stimulated Compton scattering is the main fundamental mechanism responsible for the electron acceleration at this laser intensity.

  16. Chemical modification of chitosan under high-intensity ultrasound.

    PubMed

    Cravotto, Giancarlo; Tagliapietra, Silvia; Robaldo, Bruna; Trotta, Michele

    2005-01-01

    Chitosan (CTS), a biocompatible, biodegradable, non-toxic polymer, dissolves in water only if pH is lowered under 6.5, when a substantial fraction of the amino groups is protonated. Its range of application has been much extended by partially depolymerising it or converting it to water-soluble derivatives. Working under high-intensity ultrasound at 17.8-18.5 kHz, using either a simple horn or a cup horn, we achieved a controlled depolymerization of CTS, also prepared in high yields several derivatives that can be useful intermediates for further chemical modification, as well as several water-soluble derivatives that lend themselves to a host of industrial applications. Compared to conventional methods, all these reactions went to completion in considerably shorter times at lower temperatures.

  17. Increased collection efficiency of LIFI high intensity electrodeless light source

    NASA Astrophysics Data System (ADS)

    Hafidi, Abdeslam; DeVincentis, Marc; Duelli, Markus; Gilliard, Richard

    2008-02-01

    Recently, RF driven electrodeless high intensity light sources have been implemented successfully in the projection display systems for HDTV and videowall applications. This paper presents advances made in the RF waveguide and electric field concentrator structures with the purpose of reducing effective arc size and increasing light collection. In addition, new optical designs are described that further improve system efficiency. The results of this work demonstrate that projection system light throughput is increased relative to previous implementations and performance is optimized for home theater and other front projector applications that maintain multi-year lifetime without re-lamping, complete spectral range, fast start times and high levels of dynamic contrast due to dimming flexibility in the light source system.

  18. High-intensity therapeutic ultrasound: metrological requirements versus clinical usage

    NASA Astrophysics Data System (ADS)

    Aubry, J.-F.

    2012-10-01

    High-intensity therapeutic ultrasound (HITU) is an appealing non-invasive, non-ionizing therapeutic modality with a wide range of tissue interactions ranging from transient permeabilization of cell membranes to thermal ablation. The ability to guide and monitor the treatment with an associated ultrasonic or magnetic resonance imaging device has resulted in a dramatic rise in the clinical use of therapeutic ultrasound in the past two decades. Nevertheless, the range of clinical applications and the number of patients treated has grown at a much higher pace than the definition of standards. In this paper the metrological requirements of the therapeutic beams are reviewed and are compared with the current clinical use of image-guided HITU mostly based on a practical approach. Liver therapy, a particularly challenging clinical application, is discussed to highlight the differences between some complex clinical situations and the experimental conditions of the metrological characterization of ultrasonic transducers.

  19. Comparison of Two High Intensity Acoustic Test Facilities

    NASA Astrophysics Data System (ADS)

    Launay, A.; Tadao Sakita, M.; Kim, Youngkey K.

    2004-08-01

    In two different countries, at the same period of time, the institutes in charge of the development of space activities have decided to extend their satellite integration and test center, and to implement a reverberant acoustic chamber. In Brazil the INPE laboratory (LIT : Laboratorio de Integracao e Testes) and in South Korea the KARI laboratory (SITC : Satellite Integration and Test Center) started their projects in July 2000 for the RATF (Reverberant Acoustic Test Facility) and in May 2001 for the HIAC (High Intensity Acoustic Chamber) respectively, writing the technical specifications. The kick-off meetings took place in December 2000 and in February 2002 and the opening ceremonies in December 19, 2002 in Brazil and in August 22, 2003 in Korea. This paper compares the two projects in terms of design choices, manufacturing processes, equipment installed and technical final characteristics.

  20. Digital control of high-intensity acoustic testing

    NASA Technical Reports Server (NTRS)

    Slusser, R. A.

    1975-01-01

    A high intensity acoustic test system is reported that consists of a reverberation room measuring 18 feet wide by 21 feet long by 26 feet high, with an internal volume of 10,900 cubic feet. The room is rectangular in shape. Acoustic energy is supplied through two 50-Hz cutoff exponential horns about 12 feet long. Each of the two horns has two transducers rated at 4000 acoustic watts each. A gaseous nitrogen supply is used to supply the energy. The equalized electrical signal is corrected by a circuit designed to compensate for the transducer nonlinearity, then fed into one channel of a phase linear power amplifier, then into the transducer. The amplifiers have been modified to increase their reliability. The acoustic energy in the room is monitored by six B and K 1/2-inch condenser microphones. The electrical signal from each microphone is fed into a six channel real time averager to give a spatial average of the signals.

  1. Digital control of high-intensity acoustic testing

    NASA Technical Reports Server (NTRS)

    Slusser, R. A.

    1975-01-01

    To eliminate previous system instabilities and control high-intensity acoustic tests, a digital control vibration test system is modified by a software change. Three systems for the control of acoustic testing are compared: a hybrid digital/analog system, a digital vibration system, and the same digital vibration system modified by a software change to allow acoustic testing. It is shown that the hybrid system and the modified vibration system exhibit almost equal performance, although the hybrid system performs testing twice as fast. The development of a specialized acoustic test control system is justified since it costs far less than the general-purpose vibration control system. However, the latter is much easier to set up for a test, which is important in preventing overtesting of valuable spacecraft components.

  2. Technology insight: High-intensity focused ultrasound for urologic cancers.

    PubMed

    Chaussy, Christian; Thüroff, Stefan; Rebillard, Xavier; Gelet, Albert

    2005-04-01

    The growing interest in high-intensity focused ultrasound (HIFU) technology is mainly due to its many potential applications as a minimally invasive therapy. It has been introduced to urologic oncology as a treatment for prostate and kidney cancers. While its application in the kidney is still at the clinical feasibility phase, HIFU technology is currently used in daily practice in Europe for the treatment of prostate cancer. Literature describing the results of HIFU for prostate cancer is mainly based on several series of patients from clinical development teams. The latest published results suggest that HIFU treatment is a valuable option for well-differentiated and moderately-differentiated tumors, as well as for local recurrence after external-beam radiation therapy.

  3. Characterization of high intensity focused ultrasound transducers using acoustic streaming.

    PubMed

    Hariharan, Prasanna; Myers, Matthew R; Robinson, Ronald A; Maruvada, Subha H; Sliwa, Jack; Banerjee, Rupak K

    2008-03-01

    A new approach for characterizing high intensity focused ultrasound (HIFU) transducers is presented. The technique is based upon the acoustic streaming field generated by absorption of the HIFU beam in a liquid medium. The streaming field is quantified using digital particle image velocimetry, and a numerical algorithm is employed to compute the acoustic intensity field giving rise to the observed streaming field. The method as presented here is applicable to moderate intensity regimes, above the intensities which may be damaging to conventional hydrophones, but below the levels where nonlinear propagation effects are appreciable. Intensity fields and acoustic powers predicted using the streaming method were found to agree within 10% with measurements obtained using hydrophones and radiation force balances. Besides acoustic intensity fields, the streaming technique may be used to determine other important HIFU parameters, such as beam tilt angle or absorption of the propagation medium.

  4. High Intensity Interval Training for Maximizing Health Outcomes.

    PubMed

    Karlsen, Trine; Aamot, Inger-Lise; Haykowsky, Mark; Rognmo, Øivind

    2017-04-03

    Regular physical activity and exercise training are important actions to improve cardiorespiratory fitness and maintain health throughout life. There is solid evidence that exercise is an effective preventative strategy against at least 25 medical conditions, including cardiovascular disease, stroke, hypertension, colon and breast cancer, and type 2 diabetes. Traditionally, endurance exercise training (ET) to improve health related outcomes has consisted of low- to moderate ET intensity. However, a growing body of evidence suggests that higher exercise intensities may be superior to moderate intensity for maximizing health outcomes. The primary objective of this review is to discuss how aerobic high-intensity interval training (HIIT) as compared to moderate continuous training may maximize outcomes, and to provide practical advices for successful clinical and home-based HIIT.

  5. Semicircular Canal Pressure Changes During High-intensity Acoustic Stimulation.

    PubMed

    Maxwell, Anne K; Banakis Hartl, Renee M; Greene, Nathaniel T; Benichoux, Victor; Mattingly, Jameson K; Cass, Stephen P; Tollin, Daniel J

    2017-08-01

    Acoustic stimulation generates measurable sound pressure levels in the semicircular canals. High-intensity acoustic stimuli can cause hearing loss and balance disruptions. To examine the propagation of acoustic stimuli to the vestibular end-organs, we simultaneously measured fluid pressure in the cochlea and semicircular canals during both air- and bone-conducted sound presentation. Five full-cephalic human cadaveric heads were prepared bilaterally with a mastoidectomy and extended facial recess. Vestibular pressures were measured within the superior, lateral, and posterior semicircular canals, and referenced to intracochlear pressure within the scala vestibuli with fiber-optic pressure probes. Pressures were measured concurrently with laser Doppler vibrometry measurements of stapes velocity during stimulation with both air- and bone-conduction. Stimuli were pure tones between 100 Hz and 14 kHz presented with custom closed-field loudspeakers for air-conducted sounds and via commercially available bone-anchored device for bone-conducted sounds. Pressures recorded in the superior, lateral, and posterior semicircular canals in response to sound stimulation were equal to or greater in magnitude than those recorded in the scala vestibuli (up to 20 dB higher). The pressure magnitudes varied across canals in a frequency-dependent manner. High sound pressure levels were recorded in the semicircular canals with sound stimulation, suggesting that similar acoustical energy is transmitted to the semicircular canals and the cochlea. Since these intralabyrinthine pressures exceed intracochlear pressure levels, our results suggest that the vestibular end-organs may also be at risk for injury during exposure to high-intensity acoustic stimuli known to cause trauma in the auditory system.

  6. Evaluating the Impact of Dwell Time on Solder Interconnect Durability Under Bending Loads

    NASA Astrophysics Data System (ADS)

    Menon, Sandeep; Osterman, Michael; Pecht, Michael

    2015-11-01

    With the increasing portability and miniaturization of modern-day electronics, the mechanical robustness of these systems has become more of a concern. Existing standards for conducting mechanical durability tests of electronic assemblies include bend, shock/drop, vibration, and torsion. Although these standards provide insights into both cyclic fatigue and overstress damage incurred in solder interconnects (widely regarded as the primary mode of failure in electronic assemblies), they fail to address the impact of time- dependent (creep) behavior due to sustained mechanical loads on solder interconnect durability. It has been seen in previous studies that solder durability under thermal cycling loads is inversely proportional to the dwell time or hold time at either temperature extreme of the imposed temperature cycle. Fatigue life models, which include dwell time, have been developed for solder interconnects subject to temperature cycling. However, the fatigue life models that have been developed in the literature for solder interconnects under mechanical loads fail to address the influence of the duration of loading. In this study, solder interconnect test vehicles were subjected to cyclic mechanical bending with various dwell times in order to understand the impact of the duration of mechanical loads on solder interconnect durability. The solder interconnects examined in this study were formed with 2512 resistor packages using various solder compositions [tin-lead (Sn-Pb) and 96.5Sn-3Ag-0.5Cu (SAC305)]. To evaluate the impact of dwell time, the boards were tested with 0 s, 60 s, and 300 s of dwell time at both extremes of the loading profile. It was observed that an increase in the dwell time of the loading profile resulted in a decrease in the characteristic life of the solder interconnects. The decrease in fatigue life was attributed to increased creep damage as identified using finite-element simulations. An energy partitioning approach was then used to

  7. Body armor, performance, and physiology during repeated high-intensity work tasks.

    PubMed

    Larsen, Brianna; Netto, Kevin; Skovli, Daniel; Vincs, Kim; Vu, Sarah; Aisbett, Brad

    2012-11-01

    This study examined the effect of body armor during repeated, intermittent high-intensity simulated military work. Twelve males performed 11 repetitions of a military style circuit, wearing no armor on one occasion and full armor (approximately 17 kg) on another. Performance was measured by the time to complete individual work tasks plus overall circuit time to completion. Heart rate, intestinal temperature, and rating of perceived exertion were recorded after each circuit. Participants' circuit time to completion was 7.3 +/- 1.0 seconds slower (p <0.01) when wearing armor. Shooting, vaulting, and crawling were also slower (0.8 +/- 0.2, 0.4 +/- 0.2, and 1.0 +/- 0.4 seconds, respectively; all p < or = 0.05). No differences were observed for box lifting. Higher core temperatures were reported for the armor condition for circuit's 7 to 11 (p = 0.01-0.05). Rating of perceived exertion was higher (1 +/- 0; p = 0.03) when wearing armor. No differences were observed for heart rate. Wearing armor impairs repeated high-intensity military task performance. In the relatively short work time utilized, this decrement did not accrue over time. The impairment may, then, be related to the armor load, rather than accumulating fatigue.

  8. Increased intrinsic stiffness and mineralization in femurs of adult rats after high intensity treadmill running training.

    PubMed

    Bozzini, Clarisa; Viscor, Ginés; Kristjánsson, Juan C Ríos; Picasso, Emilio; Champin, Graciela; Alippi, Rosa M; Bozzini, Carlos E

    2017-01-01

    Physical activity plays a tremendous role in determining bone mechanical behavior, which is superimposed to gravidity. Compare the geometric and material responses of the rat femur to a high intensity treadmill running training of a relatively short duration, as assessed by 3-point mechanical test. Mature male rats (180.0 ± 30 g) were assigned (7 rats/group) to no exercise (NE) or treadmill exercise (EX). After a preconditioning period, the running speed was set at 45 cm.seg-1 during 2 wks, frequency 5 d/wk, 2-hour sessions/day. Body weight and weight of the crural quadriceps were registered at euthanasia. The right femur was mechanically tested through 3-point bending. The left femur was ashed to estimate bone mineral content. Geometric and material bone properties were estimated directly or calculated by appropriate equations. 1) Final body weight was 14% reduced in EX rats, while the crural quadriceps was 47% increased. Yield and fracture loads, and structural stiffness were significantly higher in the EX rats, as were the apparent elastic modulus, the bone mineral content and the degree of mineralization. Geometric properties were not affected. High intensity treadmill running training increases bone strength and stiffness by increasing material stiffness and mineralization, without affecting geometric bone parameters.

  9. Cross-modal perceptual load: the impact of modality and individual differences.

    PubMed

    Sandhu, Rajwant; Dyson, Benjamin James

    2016-05-01

    Visual distractor processing tends to be more pronounced when the perceptual load (PL) of a task is low compared to when it is high [perpetual load theory (PLT); Lavie in J Exp Psychol Hum Percept Perform 21(3):451-468, 1995]. While PLT is well established in the visual domain, application to cross-modal processing has produced mixed results, and the current study was designed in an attempt to improve previous methodologies. First, we assessed PLT using response competition, a typical metric from the uni-modal domain. Second, we looked at the impact of auditory load on visual distractors, and of visual load on auditory distractors, within the same individual. Third, we compared individual uni- and cross-modal selective attention abilities, by correlating performance with the visual Attentional Network Test (ANT). Fourth, we obtained a measure of the relative processing efficiency between vision and audition, to investigate whether processing ease influences the extent of distractor processing. Although distractor processing was evident during both attend auditory and attend visual conditions, we found that PL did not modulate processing of either visual or auditory distractors. We also found support for a correlation between the uni-modal (visual) ANT and our cross-modal task but only when the distractors were visual. Finally, although auditory processing was more impacted by visual distractors, our measure of processing efficiency only accounted for this asymmetry in the auditory high-load condition. The results are discussed with respect to the continued debate regarding the shared or separate nature of processing resources across modalities.

  10. Investigation of impact loading rate effects on the ligamentous cervical spinal load-partitioning using finite element model of functional spinal unit C2-C3.

    PubMed

    Mustafy, Tanvir; El-Rich, Marwan; Mesfar, Wissal; Moglo, Kodjo

    2014-09-22

    The cervical spine functions as a complex mechanism that responds to sudden loading in a unique manner, due to intricate structural features and kinematics. The spinal load-sharing under pure compression and sagittal flexion/extension at two different impact rates were compared using a bio-fidelic finite element (FE) model of the ligamentous cervical functional spinal unit (FSU) C2-C3. This model was developed using a comprehensive and realistic geometry of spinal components and material laws that include strain rate dependency, bone fracture, and ligament failure. The range of motion, contact pressure in facet joints, failure forces in ligaments were compared to experimental findings. The model demonstrated that resistance of spinal components to impact load is dependent on loading rate and direction. For the loads applied, stress increased with loading rate in all spinal components, and was concentrated in the outer intervertebral disc (IVD), regions of ligaments to bone attachment, and in the cancellous bone of the facet joints. The highest stress in ligaments was found in capsular ligament (CL) in all cases. Intradiscal pressure (IDP) in the nucleus was affected by loading rate change. It increased under compression/flexion but decreased under extension. Contact pressure in the facet joints showed less variation under compression, but increased significantly under flexion/extension particularly under extension. Cancellous bone of the facet joints region was the only component fractured and fracture occurred under extension at both rates. The cervical ligaments were the primary load-bearing component followed by the IVD, endplates and cancellous bone; however, the latter was the most vulnerable to extension as it fractured at low energy impact.

  11. Impact of arterial load on the agreement between pulse pressure analysis and esophageal Doppler

    PubMed Central

    2013-01-01

    Introduction The reliability of pulse pressure analysis to estimate cardiac output is known to be affected by arterial load changes. However, the contribution of each aspect of arterial load could be substantially different. In this study, we evaluated the agreement of eight non-commercial algorithms of pulse pressure analysis for estimating cardiac output (PPCO) with esophageal Doppler cardiac output (EDCO) during acute changes of arterial load. In addition, we aimed to determine the optimal arterial load parameter that could detect a clinically significant difference between PPCO and the EDCO. Methods We included mechanically ventilated patients monitored with a prototype esophageal Doppler (CardioQ-Combi™, Deltex Medical, Chichester, UK) and an indwelling arterial catheter who received a fluid challenge or in whom the vasoactive medication was introduced or modified. Initial calibration of PPCO was made with the baseline value of EDCO. We evaluated several aspects of arterial load: total systemic vascular resistance (TSVR = mean arterial pressure [MAP]/EDCO * 80), net arterial compliance (C = EDCO-derived stroke volume/pulse pressure), and effective arterial elastance (Ea = 0.9 * systolic blood pressure/EDCO-derived stroke volume). We compared CO values with Bland-Altman analysis, four-quadrant plot and a modified polar plot (with least significant change analysis). Results A total of 16,964-paired measurements in 53 patients were performed (median 271; interquartile range: 180-415). Agreement of all PPCO algorithms with EDCO was significantly affected by changes in arterial load, although the impact was more pronounced during changes in vasopressor therapy. When looking at different parameters of arterial load, the predictive abilities of Ea and C were superior to TSVR and MAP changes to detect a PPCO-EDCO discrepancy ≥ 10% in all PPCO algorithms. An absolute Ea change > 8.9 ± 1.7% was associated with a PPCO-EDCO discrepancy ≥ 10% in most algorithms

  12. Cavitation erosion prediction based on analysis of flow dynamics and impact load spectra

    NASA Astrophysics Data System (ADS)

    Mihatsch, Michael S.; Schmidt, Steffen J.; Adams, Nikolaus A.

    2015-10-01

    Cavitation erosion is the consequence of repeated collapse-induced high pressure-loads on a material surface. The present paper assesses the prediction of impact load spectra of cavitating flows, i.e., the rate and intensity distribution of collapse events based on a detailed analysis of flow dynamics. Data are obtained from a numerical simulation which employs a density-based finite volume method, taking into account the compressibility of both phases, and resolves collapse-induced pressure waves. To determine the spectrum of collapse events in the fluid domain, we detect and quantify the collapse of isolated vapor structures. As reference configuration we consider the expansion of a liquid into a radially divergent gap which exhibits unsteady sheet and cloud cavitation. Analysis of simulation data shows that global cavitation dynamics and dominant flow events are well resolved, even though the spatial resolution is too coarse to resolve individual vapor bubbles. The inviscid flow model recovers increasingly fine-scale vapor structures and collapses with increasing resolution. We demonstrate that frequency and intensity of these collapse events scale with grid resolution. Scaling laws based on two reference lengths are introduced for this purpose. We show that upon applying these laws impact load spectra recorded on experimental and numerical pressure sensors agree with each other. Furthermore, correlation between experimental pitting rates and collapse-event rates is found. Locations of high maximum wall pressures and high densities of collapse events near walls obtained numerically agree well with areas of erosion damage in the experiment. The investigation shows that impact load spectra of cavitating flows can be inferred from flow data that captures the main vapor structures and wave dynamics without the need for resolving all flow scales.

  13. Cavitation erosion prediction based on analysis of flow dynamics and impact load spectra

    SciTech Connect

    Mihatsch, Michael S. Schmidt, Steffen J.; Adams, Nikolaus A.

    2015-10-15

    Cavitation erosion is the consequence of repeated collapse-induced high pressure-loads on a material surface. The present paper assesses the prediction of impact load spectra of cavitating flows, i.e., the rate and intensity distribution of collapse events based on a detailed analysis of flow dynamics. Data are obtained from a numerical simulation which employs a density-based finite volume method, taking into account the compressibility of both phases, and resolves collapse-induced pressure waves. To determine the spectrum of collapse events in the fluid domain, we detect and quantify the collapse of isolated vapor structures. As reference configuration we consider the expansion of a liquid into a radially divergent gap which exhibits unsteady sheet and cloud cavitation. Analysis of simulation data shows that global cavitation dynamics and dominant flow events are well resolved, even though the spatial resolution is too coarse to resolve individual vapor bubbles. The inviscid flow model recovers increasingly fine-scale vapor structures and collapses with increasing resolution. We demonstrate that frequency and intensity of these collapse events scale with grid resolution. Scaling laws based on two reference lengths are introduced for this purpose. We show that upon applying these laws impact load spectra recorded on experimental and numerical pressure sensors agree with each other. Furthermore, correlation between experimental pitting rates and collapse-event rates is found. Locations of high maximum wall pressures and high densities of collapse events near walls obtained numerically agree well with areas of erosion damage in the experiment. The investigation shows that impact load spectra of cavitating flows can be inferred from flow data that captures the main vapor structures and wave dynamics without the need for resolving all flow scales.

  14. Fate of alkylphenolic compounds during activated sludge treatment: impact of loading and organic composition.

    PubMed

    McAdam, Ewan J; Bagnall, John P; Soares, Ana; Koh, Yoong K K; Chiu, Tze Y; Scrimshaw, Mark D; Lester, John N; Cartmell, Elise

    2011-01-01

    The impact of loading and organic composition on the fate of alkylphenolic compounds in the activated sludge plant (ASP) has been studied. Three ASP designs comprising carbonaceous, carbonaceous/nitrification, and carbonaceous/nitrification/denitrification treatment were examined to demonstrate the impact of increasing levels of process complexity and to incorporate a spectrum of loading conditions. Based on mass balance, overall biodegradation efficiencies for nonylphenol ethoxylates (NPEOs), short chain carboxylates (NP(1-3)EC) and nonylphenol (NP) were 37%, 59%, and 27% for the carbonaceous, carbonaceous/nitrification, and carbonaceous/nitrification/denitrification ASP, respectively. The presence of a rich community of ammonia oxidizing bacteria does not necessarily facilitate effective alkylphenolic compound degradation. However, a clear correlation between alkylphenolic compound loading and long chain ethoxylate compound biodegradation was determined at the three ASPs, indicating that at higher initial alkylphenolic compound concentrations (or load), greater ethoxylate biotransformation can occur. In addition, the impact of settled sewage organic composition on alkylphenolic compound removal was evaluated. A correlation between the ratio of chemical oxygen demand (COD) to alkylphenolic compound concentration and biomass activity was determined, demonstrating the inhibiting effect of bulk organic matter on alkylphenol polyethoxylate transformation activity. At all three ASPs the biodegradation pathway proposed involves the preferential biodegradation of the amphiphilic ethoxylated compounds, after which the preferential attack of the lipophilic akylphenol moiety occurs. The extent of ethoxylate biodegradation is driven by the initial alkylphenolic compound concentration and the proportion of COD constituted by the alkylphenol polyethoxylates (APEOs) and their metabolites relative to the bulk organic concentration of the sewage composed of proteins, acids, fats

  15. Impact of Groundwater Flow and Energy Load on Multiple Borehole Heat Exchangers.

    PubMed

    Dehkordi, S Emad; Schincariol, Robert A; Olofsson, Bo

    2015-01-01

    The effect of array configuration, that is, number, layout, and spacing, on the performance of multiple borehole heat exchangers (BHEs) is generally known under the assumption of fully conductive transport. The effect of groundwater flow on BHE performance is also well established, but most commonly for single BHEs. In multiple-BHE systems the effect of groundwater advection can be more complicated due to the induced thermal interference between the boreholes. To ascertain the influence of groundwater flow and borehole arrangement, this study investigates single- and multi-BHE systems of various configurations. Moreover, the influence of energy load balance is also examined. The results from corresponding cases with and without groundwater flow as well as balanced and unbalanced energy loads are cross-compared. The groundwater flux value, 10(-7) m/s, is chosen based on the findings of previous studies on groundwater flow interaction with BHEs and thermal response tests. It is observed that multi-BHE systems with balanced loads are less sensitive to array configuration attributes and groundwater flow, in the long-term. Conversely, multi-BHE systems with unbalanced loads are influenced by borehole array configuration as well as groundwater flow; these effects become more pronounced with time, unlike when the load is balanced. Groundwater flow has more influence on stabilizing loop temperatures, compared to array characteristics. Although borehole thermal energy storage (BTES) systems have a balanced energy load function, preliminary investigation on their efficiency shows a negative impact by groundwater which is due to their dependency on high temperature gradients between the boreholes and surroundings.

  16. Pathways of nutrient loading and impacts on plant diversity in a New York peatland

    USGS Publications Warehouse

    Drexler, J.Z.; Bedford, B.L.

    2002-01-01

    Nutrient loading is a subtle, yet serious threat to the preservation of high diversity wetlands such as peatlands. Pathways of nutrient loading and impacts on plant diversity in a small peatland in New York State, USA were determined by collecting and analyzing a suite of hydrogeological, hydro-chemical, soil, and vegetation data. Piezometer clusters within an intensive network constituted hydro-chemical sampling points and focal points for randomly selected vegetation quadrats and soil-coring locations. Hydrogeological data and nutrient analyses showed that P and K loading occurred chiefly by means of overland flow from an adjacent farm field, whereas N loading occurred predominantly through ground-water flow from the farm field. Redundancy analysis and polynomial regression showed that nutrients, particularly total P in peat, total K in peat, extractable NH4-N, and NO3-N flux in ground water, were strongly negatively correlated with plant diversity measures at the site. No other environmental variables except vegetation measures associated with eutrophication demonstrated such a strong relationship with plant diversity. Nitrate loading over 4 mg m -2 day-1 was associated with low plant diversity, and Ca fluxes between 80 and 130 mg m-2 day-1 were associated with high plant diversity. Areas in the site with particularly low vascular plant and bryophyte species richness and Shannon-Wiener diversity (H') occurred adjacent to the farm field and near a hillside spring. High H' and species richness of vascular plants and bryophytes occurred in areas that were further removed from agriculture, contained no highly dominant vegetation, and were situated directly along the ground-water flow paths of springs. These areas were characterized by relatively constant water levels and consistent, yet moderate fluxes of base cations and nutrients. Overall, this study demonstrates that knowledge of site hydrogeology is crucial for determining potential pathways of nutrient loading

  17. Low velocity impact monitoring of composite wing structure under simulated wing loading condition using fiber Bragg grating sensors

    NASA Astrophysics Data System (ADS)

    Shrestha, Pratik; Park, Yurim; Kwon, Hyunseok; Kim, Chun-Gon

    2017-04-01

    A low velocity impact onto a composite structure can result in the occurrence of barely visible impact damage (BVID), which is difficult to detect. Therefore, the low velocity impact monitoring of composite structures is highly desirable for impact detection and localization. In this paper, low velocity impacts on a composite wing under a simulated wing loading condition were monitored using six multiplexed fiber Bragg grating (FBG) sensors and localized using error outlier based impact localization algorithm. The impact response signals from the FBG sensors were sampled at a rate of 100 kHz using high-speed interrogator. The impacts were localized with an average error of 18.4 mm.

  18. Behavior of plywood and fiberglass steel composite tube structures subjected to impact loading

    NASA Astrophysics Data System (ADS)

    Armaghani, Seyamend Bilind

    Paratransit buses are custom built as the major vehicle manufacturer produces the custom built passenger cage installed on the chassis for the Paratransit bus. In order for these Paratransit bus members to be sufficient, they have to be evaluated for crashworthiness and energy absorption. This has prompted Florida Department of Transportation (FDOT) to fund research for the safety evaluation of Paratransit busses consisting of crash and safety analysis. There has been a large body of research done on steel subjected to static loads, but more research is needed for steel applied under dynamic loading and high speeds in order to improve crashworthiness in events such as rollovers and side impacts. Bare steel Hollow Structural Section (HSS) tubing are used a lot as structural members of Paratransit buses because of their lightness and progressive buckling under loading. The research will be conducted on quantifying the tubing's behavior under bending by conducting static three point bending and impact loading tests. In addition to the bare tubing, plywood and fiberglass composites are investigated because they are both strong and lightweight and their behavior under dynamic loading hasn't been quantified. As a result, the main purpose of this research is to quantify the differences between the dynamic and static behavior of plywood steel composite and fiberglass steel composite tubing and compare these findings with those of bare steel tubing. The differences will be quantified using detailed and thorough experiments that will examine the composites behavior under both static and dynamic loading. These tests will determine if there are any advantages of using the composite materials and thus allow for recommendations to be made to the FDOT with the goal of improving the safety of Paratransit busses. Tensile tests were conducted to determine the material properties of the tested specimens. Before the static and dynamic experiments are run to investigate the differences

  19. Strain rate effects for concrete and fiber-reinforced concrete subjected to impact loading. Final report, September 1982-August 1987

    SciTech Connect

    Shah, S.P.

    1987-10-01

    Despite it's extensive use, low tensile strength has been recognized as one of the major drawbacks of concrete. Although one has learned to avoid exposing concrete structures to adverse static tensile loads, these structures cannot be shielded from short duration dynamic tensile loads. Such loads originate from sources such as impact from missiles and projectiles, wind gusts, earthquakes and machine vibrations. In addition, modern computer-aided analysis and use of concrete for special structures such as reactor containment vessels, missile storage silos and fall-out shelters, has led to a growing interest in the cracking behavior of concrete. Experimental results indicate that the fracture strength and cracking behavior of concrete are affected by the rate of loading. To accurately predict the structural response under impact conditions, the knowledge of behavior of concrete at high rates of loading is essential. Using a two degree of freedom model guidelines were developed for designing an impact test setup, thus enabling one to conduct impact tests free of adverse inertial effects. Based on these guidelines, the author has developed an instrumented modified Charpy impact testing system. This experimental test setup was used to obtain basic information such as load-deflection relationship, fracture toughness, crack velocity (measured using Krak Gages), and load-strain history during an impact fracture event of plain concrete and SFRC.

  20. Upper and Lower Neck Loads in Belted Human Surrogates in Frontal Impacts

    PubMed Central

    Yoganandan, Narayan; Pintar, Frank A.; Moore, Jason; Rinaldi, James; Schlick, Michael; Maiman, Dennis J.

    2012-01-01

    The upper and lower neck loads in the restrained Hybrid III dummy and Test Device for Human Occupant Restraint (THOR) were computed in simulated frontal impact sled tests at low, medium, and high velocities; repeatability performance of the two dummies were evaluated at all energy inputs; peak forces and moments were compared with computed loads at the occipital condyles and cervical-thoracic junctions from tests using post mortem human surrogates (PMHS). A custom sled buck was used to position the surrogates. Repeated tests were conducted at each velocity for each dummy and sufficient time was allowed to elapse between the two experiments. The upper and lower neck forces and moments were determined from load cell measures and its locations with respect to the ends of the neck. Both dummies showed good repeatability for axial and shear forces and bending moments at all changes in velocity inputs. Morphological characteristics in the neck loading responses were similar in all surrogates, although the peak magnitudes of the variables differed. In general, the THOR better mimicked the PMHS response than the Hybrid III dummy, and factors such as neck design and chest compliance were attributed to the observed variations. While both dummies were not designed for use at the two extremes of the tested velocities, results from the present study indicate that, currently the THOR may be the preferred anthropomorphic testing device in crashworthiness research studies and full-scale vehicle tests at all velocities. PMID:23169123

  1. The impact of load on lower body performance variables during the hang power clean.

    PubMed

    Suchomel, Timothy J; Beckham, George K; Wright, Glenn A

    2014-03-01

    This study examined the impact of load on lower body performance variables during the hang power clean. Fourteen men performed the hang power clean at loads of 30%, 45%, 65%, and 80% 1RM. Peak force, velocity, power, force at peak power, velocity at peak power, and rate of force development were compared at each load. The greatest peak force occurred at 80% 1RM. Peak force at 30% 1RM was statistically lower than peak force at 45% (p = 0.022), 65% (p = 0.010), and 80% 1RM (p = 0.018). Force at peak power at 65% and 80% 1RM was statistically greater than force at peak power at 30% (p < 0.01) and 45% 1RM (p < 0.01). The greatest rate of force development occurred at 30% 1RM, but was not statistically different from the rate of force development at 45%, 65%, and 80% 1RM. The rate of force development at 65% 1RM was statistically greater than the rate of force development at 80% 1RM (p = 0.035). No other statistical differences existed in any variable existed. Changes in load affected the peak force, force at peak power, and rate of force development, but not the peak velocity, power, or velocity at peak power.

  2. Micro CT Analysis of Dynamic Damage in Laminates: Impact vs. blast loading

    NASA Astrophysics Data System (ADS)

    Coles, Laurence A.; Roy, Anish; Silberschmidt, Vadim V.

    2017-05-01

    Dynamic loading is often an unavoidable condition in various applications of carbon-fibre-reinforced polymers and can cause various modes of damage. Realisation of dynamic damage in composites can differ significantly from that under quasi-static loading conditions. A comprehensive study of damage in composites caused by a wide variety of impact and blast loading is currently lacking. The work presents a detailed analysis of damage in specimens of a 2×2 twill weave T300 carbon-fibre/epoxy composite subjected to ballistic loading with both steel and ice projectiles (with energies from 95 J to 865 J at 70-90 m/s and 300-500 m/s, respectively) and air blast (with incident pressures of 0.4 MPa, 0.6 MPa and 0.8 MPa and wave speeds between 650 m/s and 950 m/s). The resultant damage was analysed in-depth based on detailed volumetric data obtained with high-resolution X-ray micro computed tomography.

  3. Protective Effectiveness of Porous Shields Under the Influence of High-Speed Impact Loading

    NASA Astrophysics Data System (ADS)

    Kramshonkov, E. N.; Krainov, A. V.; Shorohov, P. V.

    2016-02-01

    The results of numerical simulations of a compact steel impactor with the aluminum porous shields under high-speed shock loading are presented. The porosity of barrier varies in wide range provided that its mass stays the same, but the impactor has always equal (identical) mass. Here presented the final assessment of the barrier perforation speed depending on its porosity and initial shock speed. The range of initial impact speed varies from 1 to 10 km/s. Physical phenomena such as: destruction, melting, vaporization of a interacting objects are taken into account. The analysis of a shield porosity estimation disclosed that the protection effectiveness of porous shield reveals at the initial impact speed grater then 1.5 km/s, and it increases when initial impact speed growth.

  4. The deformation and failure response of closed-cell PMDI foams subjected to dynamic impact loading

    SciTech Connect

    Koohbor, Behrad; Mallon, Silas; Kidane, Addis; Lu, Wei -Yang

    2015-04-07

    The present work aims to investigate the bulk deformation and failure response of closed-cell Polymeric Methylene Diphenyl Diisocyanate (PMDI) foams subjected to dynamic impact loading. First, foam specimens of different initial densities are examined and characterized in quasi-static loading conditions, where the deformation behavior of the samples is quantified in terms of the compressive elastic modulus and effective plastic Poisson's ratio. Then, the deformation response of the foam specimens subjected to direct impact loading is examined by taking into account the effects of material compressibility and inertia stresses developed during deformation, using high speed imaging in conjunction with 3D digital image correlation. The stress-strain response and the energy absorption as a function of strain rate and initial density are presented and the bulk failure mechanisms are discussed. As a result, it is observed that the initial density of the foam and the applied strain rates have a substantial influence on the strength, bulk failure mechanism and the energy dissipation characteristics of the foam specimens.

  5. The deformation and failure response of closed-cell PMDI foams subjected to dynamic impact loading

    DOE PAGES

    Koohbor, Behrad; Mallon, Silas; Kidane, Addis; ...

    2015-04-07

    The present work aims to investigate the bulk deformation and failure response of closed-cell Polymeric Methylene Diphenyl Diisocyanate (PMDI) foams subjected to dynamic impact loading. First, foam specimens of different initial densities are examined and characterized in quasi-static loading conditions, where the deformation behavior of the samples is quantified in terms of the compressive elastic modulus and effective plastic Poisson's ratio. Then, the deformation response of the foam specimens subjected to direct impact loading is examined by taking into account the effects of material compressibility and inertia stresses developed during deformation, using high speed imaging in conjunction with 3D digitalmore » image correlation. The stress-strain response and the energy absorption as a function of strain rate and initial density are presented and the bulk failure mechanisms are discussed. As a result, it is observed that the initial density of the foam and the applied strain rates have a substantial influence on the strength, bulk failure mechanism and the energy dissipation characteristics of the foam specimens.« less

  6. The high velocity impact loading on symmetrical and woven hybrid composite laminates

    NASA Astrophysics Data System (ADS)

    Jin, Martin; Richardson, Mel; Zhang, Zhong Yi

    2007-07-01

    Space structures use fibre composite materials, due to their lightweight. This paper examines the impact response of symmetrical and hybrid composite laminates. Special attention is given to the stacking sequences used. The experimental study of structures has always provided a major contribution to our understanding. Even with the formidable growth in the use and capacity of computing power the need for experimental measurement is as compelling as ever. The design of hybrid composite structures is complicated by the number of design variables and the interaction of the constituents is the composite system. Since it is desirable to experimentally test the design and it is not practical to test a full scale model, the structural/material similitude concept is used to create a small scale model with a similar structural response. In the current study, experimental investigations were carried out to determine the response of four different combinations of hybrid laminates to low-velocity impact loading using an instrumented impact testing machine. Hybrid laminates were fabricated with twill weave carbon fabric and plain weave S2-glass fabric using vacuum assisted resin molding process with SC-15 epoxy resin system. Response of carbon/epoxy and glass/epoxy laminates was also investigated to compare with that of hybrid samples. Square laminates of size 100 mm and nominal thickness of 3 mm were subjected to low-velocity impact loading at four energy levels of 10, 20, 30 and 40 J. Results of the study indicate that there is considerable improvement in the load carrying capability of hybrid composites as compared to carbon/epoxy laminates with slight reduction in stiffness.

  7. New Zealand Blackcurrant Extract Improves High-Intensity Intermittent Running.

    PubMed

    Perkins, Ian Craig; Vine, Sarah Anne; Blacker, Sam David; Willems, Mark Elisabeth Theodorus

    2015-10-01

    We examined the effect of New Zealand blackcurrant (NZBC) extract on high-intensity intermittent running and postrunning lactate responses. Thirteen active males (age: 25 ± 4 yrs, height: 1.82 ± 0.07 m, body mass: 81 ± 14 kg, VO2max: 56 ± 4 ml·kg-1·min-1, vVO2max: 17.6 ± 0.8 km·h-1) performed a treadmill running protocol to exhaustion, which consisted of stages with 6 × 19 s of sprints with 15 s of low-intensity running between sprints. Interstage rest time was 1 min and stages were repeated with increasing sprint speeds. Subjects consumed capsuled NZBC extract (300 mg·day-1 CurraNZ; containing 105 mg anthocyanin) or placebo for 7 days (double-blind, randomized, crossover design, wash-out at least 14 days). Blood lactate was collected for 30 min postexhaustion. NZBC increased total running distance by 10.6% (NZBC: 4282 ± 833 m, placebo: 3871 ± 622 m, p = .02), with the distance during sprints increased by 10.8% (p = .02). Heart rate, oxygen uptake, lactate and rating of perceived exertion were not different between conditions for the first 4 stages completed by all subjects. At exhaustion, blood lactate tended to be higher for NZBC (NZBC: 6.01 ± 1.07 mmol·L-1, placebo: 5.22 ± 1.52 mmol·L-1, p = .07). There was a trend for larger changes in lactate following 15 min (NZBC: -2.89 ± 0.51 mmol·L-1, placebo: -2.46 ± 0.39 mmol·L-1, p = .07) of passive recovery. New Zealand blackcurrant extract (CurraNZ) may enhance performance in sports characterized by high-intensity intermittent exercise as greater distances were covered with repeated sprints, there was higher lactate at exhaustion, and larger changes in lactate during early recovery after repeated sprints to exhaustion.

  8. HIGH INTENSITY PERFORMANCE AND UPGRADES AT THE BROOKHAVEN AGS

    SciTech Connect

    ROSER,T.

    1998-05-04

    Fig. 1 shows the present layout of the AGS-RHIC accelerator complex. The high intensity proton beam of the AGS is used both for the slow-extracted-beam (SEB) area with many target station to produce secondary beams and the fast-extracted-beam (FEB) line used for the production of muons for the g-2 experiment and for high intensity target testing for the spallation neutron sources and muon production targets for the muon collider. The same FEB line will also be used for the transfer of beam to RHIC. The proton beam intensity in the AGS has increased steadily over the 35 year existence of the AGS, but the most dramatic increase occurred over the last couple of years with the addition of the new AGS Booster[1]. In Fig. 2 the history of the AGS intensity improvements is shown and the major upgrades are indicated. The AGS Booster has one quarter the circumference of the AGS and therefore allows four Booster beam pulses to be stacked in the AGS at an injection energy of 1.5--1.9 GeV. At this increased energy, space charge forces are much reduced and this in turn allows for the dramatic increase in the AGS beam intensity. The 200 MeV LINAC is being used both for the injection into the Booster as well as an isotope production facility. A recent upgrade of the LINAC rf system made it possible to operated at an average H{sup {minus}} current of 150 {micro}A and a maximum of 12 x 10{sup 13} H{sup {minus}} per 500 {micro}s LINAC pulse for the isotope production target. Typical beam currents during the 500 {micro}s pulse are about 80 mA at the source, 60 mA after the 750 keV RFQ, 38 mA after the first LINAC tank (10 MeV), and 37 mA at end of the LINAC at 200 MeV. The normalized beam emittance is about 2 {pi} mm mrad for 95% of the beam and the beam energy spread is about {+-}1.2 MeV. A magnetic fast chopper installed at 750 keV allows the shaping of the beam injected into the Booster to avoid excessive beam loss.

  9. Effects of selected softball bat loading strategies on impact reaction impulse.

    PubMed

    Noble, L; Eck, J

    1986-02-01

    Interior loading strategies to modify the location and size of the effective hitting area of aluminum softball bats were identified. The effects of these strategies on theoretically derived and empirically determined relevant mechanical parameters were compared. Loading strategies consisted of adding 315 g to the interior of three similar (790 g) aluminum softball bats: at the center of mass of the original bat (bat C); at the ends of the bat and distributed so that the center of mass was unchanged, (bat A); and at the ends of the bat and distributed so that the moment of inertia about the swing axis (I1) was the same as that of bat C (bat B). The following parameters were derived theoretically by considering the bat as a physical pendulum and empirically by observing the impact reaction impulse on the axis of suspension: moment of inertia about the suspension axis (I0); moment of inertia about the swing axis; distance from the suspension axis to the center of percussion; and the slope of the impact reaction impulse (P1) relative to the impact impulse (P) as a function of impact location. These values for each bat were compared. Both empirical and theoretically derived data indicated that: the center of percussion of bat B was farther away from the axis than bats A and C; the moment of inertia about the swing axis of bat A was much greater than that of bats B and C; and the slope of the impact reaction regression line as a function of impact location for bat B was significantly less than that of the other bats. Thus, the effective hitting area of bat B was moved toward the barrel end of the bat and enlarged without a substantial increase in the moment of inertia about the swing axis.

  10. Measurement of peak impact loads differ between accelerometers - Effects of system operating range and sampling rate.

    PubMed

    Ziebart, Christina; Giangregorio, Lora M; Gibbs, Jenna C; Levine, Iris C; Tung, James; Laing, Andrew C

    2017-06-14

    A wide variety of accelerometer systems, with differing sensor characteristics, are used to detect impact loading during physical activities. The study examined the effects of system characteristics on measured peak impact loading during a variety of activities by comparing outputs from three separate accelerometer systems, and by assessing the influence of simulated reductions in operating range and sampling rate. Twelve healthy young adults performed seven tasks (vertical jump, box drop, heel drop, and bilateral single leg and lateral jumps) while simultaneously wearing three tri-axial accelerometers including a criterion standard laboratory-grade unit (Endevco 7267A) and two systems primarily used for activity-monitoring (ActiGraph GT3X+, GCDC X6-2mini). Peak acceleration (gmax) was compared across accelerometers, and errors resulting from down-sampling (from 640 to 100Hz) and range-limiting (to ±6g) the criterion standard output were characterized. The Actigraph activity-monitoring accelerometer underestimated gmax by an average of 30.2%; underestimation by the X6-2mini was not significant. Underestimation error was greater for tasks with greater impact magnitudes. gmax was underestimated when the criterion standard signal was down-sampled (by an average of 11%), range limited (by 11%), and by combined down-sampling and range-limiting (by 18%). These effects explained 89% of the variance in gmax error for the Actigraph system. This study illustrates that both the type and intensity of activity should be considered when selecting an accelerometer for characterizing impact events. In addition, caution may be warranted when comparing impact magnitudes from studies that use different accelerometers, and when comparing accelerometer outputs to osteogenic impact thresholds proposed in literature. Crown Copyright © 2017. Published by Elsevier Ltd. All rights reserved.

  11. [High intensity interval training improves glycemic control and aerobic capacity in glucose intolerant patients].

    PubMed

    Mancilla, Rodrigo; Torres, Paola; Álvarez, Cristian; Schifferli, Ingrid; Sapunar, Jorge; Díaz, Erik

    2014-01-01

    Proper exercise training modifies intra miocellular energy utilization, glucose transport and mitochondrial biogenesis. To determine the therapeutic effects of a high intensity intermittent training (HIIT) program on glucose homeostasis, physical fitness and body fat in glucose intolerant patients. Eighteen patients with overweight or obesity and glucose intolerance were invited to participate in an exercise program consisting in three sessions per week for 3 months. Ten participants aged 35 ± 13 years who attended > 26 of the planned 36 sessions, were considered as adherent to exercise. The other eight participants aged 37 ± 17 years, who attended to a mean of 13 sessions, were considered as non-adherent. Both groups had similar body weight, body mass index, body fat, plasma glucose 2 h after an oral glucose load and maximal oxygen uptake. All these variables were measured at the end of exercise intervention. Each session consisted of 1 min exercise of cycling at maximal intensity until muscle fatigue followed by 2 min rest, repeated 10 times. Among adherent participants, twelve weeks of HIIT improved significantly maximal oxygen uptake (6.1 + 3.6 mL/kg/min or 24.6%), reduced 2 h post load blood glucose (-33.7 + 47.9 mg/dL or -12.5%) and body fat (-4.3 + 5.6 kg). No significant changes were observed in the non-adherent group. HIIT exercise reduces blood glucose after an oral load in glucose intolerant patients.

  12. Analytical and numerical studies on the nonlinear dynamic response of orthotropic membranes under impact load

    NASA Astrophysics Data System (ADS)

    Liu, Changjiang; Zheng, Zhoulian; Yang, Xiaoyan

    2016-12-01

    Orthotropic membrane components and structures are widely used in building structures, instruments and meters, electronic engineering, space and aeronautics, etc., because of their light weights. However, the same lightweight combined with low stiffness make membranes prone to vibration under dynamic loads, and in some cases the vibration may lead to structural failure. Herein, the undamped nonlinear vibration response of pretension rectangular orthotropic membrane structures subjected to impact loading is studied by analytical and numerical methods. The analytical solution is obtained by solving the governing equations by the Bubnov-Galerkin method and the Lindstedt-Poincaré perturbation method. Numerical analysis has also been carried out based on the same theoretical model. The analytical and numerical results have been compared and analyzed, and the influence of various model parameters on membrane vibration discussed. The results obtained herein provide some theoretical basis for the vibration control and dynamic design of orthotropic membrane components and structures.

  13. Climate change impacts on runoff, sediment, and nutrient loads in an agricultural watershed in the Lower Mississippi River Basin

    USDA-ARS?s Scientific Manuscript database

    Projected climate change can impact various aspects of agricultural systems, including the nutrient and sediment loads exported from agricultural fields. This study evaluated the potential changes in runoff, sediment, nitrogen, and phosphorus loads using projected climate estimates from 2041 – 2070 ...

  14. A review of adolescent high-intensity interval training.

    PubMed

    Logan, Greig R M; Harris, Nigel; Duncan, Scott; Schofield, Grant

    2014-08-01

    Despite the promising evidence supporting positive effects of high-intensity interval training (HIIT) on the metabolic profile in adults, there is limited research targeting adolescents. Given the rising burden of chronic disease, it is essential to implement strategies to improve the cardiometabolic health in adolescence, as this is a key stage in the development of healthy lifestyle behaviours. This narrative review summarises evidence of the relative efficacy of HIIT regarding the metabolic health of adolescents. Methodological inconsistencies confound our ability to draw conclusions; however, there is meaningful evidence supporting HIIT as a potentially efficacious exercise modality for use in the adolescent cohort. Future research must examine the effects of various HIIT protocols to determine the optimum strategy to deliver cardiometabolic health benefits. Researchers should explicitly show between-group differences for HIIT intervention and steady-state exercise or control groups, as the magnitude of difference between HIIT and other exercise modalities is of key interest to public health. There is scope for research to examine the palatability of HIIT as an exercise modality for adolescents through investigating perceived enjoyment during and after HIIT, and consequent long-term exercise adherence.

  15. High intensity focused ultrasound in clinical tumor ablation

    PubMed Central

    Zhou, Yu-Feng

    2011-01-01

    Recent advances in high intensity focused ultrasound (HIFU), which was developed in the 1940s as a viable thermal tissue ablation approach, have increased its popularity. In clinics, HIFU has been applied to treat a variety of solid malignant tumors in a well-defined volume, including the pancreas, liver, prostate, breast, uterine fibroids, and soft-tissue sarcomas. In comparison to conventional tumor/cancer treatment modalities, such as open surgery, radio- and chemo-therapy, HIFU has the advantages of non-invasion, non-ionization, and fewer complications after treatment. Over 100 000 cases have been treated throughout the world with great success. The fundamental principles of HIFU ablation are coagulative thermal necrosis due to the absorption of ultrasound energy during transmission in tissue and the induced cavitation damage. This paper reviews the clinical outcomes of HIFU ablation for applicable cancers, and then summarizes the recommendations for a satisfactory HIFU treatment according to clinical experience. In addition, the current challenges in HIFU for engineers and physicians are also included. More recent horizons have broadened the application of HIFU in tumor treatment, such as HIFU-mediated drug delivery, vessel occlusion, and soft tissue erosion (“histotripsy”). In summary, HIFU is likely to play a significant role in the future oncology practice. PMID:21603311

  16. Spectroscopic imaging of metal halide high-intensity discharge lamps

    NASA Astrophysics Data System (ADS)

    Bonvallet, Geoffrey A.

    The body of this work consists of three main research projects. An optical- and near-ultraviolet-wavelength absorption study sought to determine absolute densities of ground and excited level Sc atoms, ground level Sc + ions, and ground level Na atoms in a commercial 250 W metal halide high intensity discharge lamp during operation. These measurements also allowed the determination of the arc temperature and absolute electron density as functions of radius. Through infrared emission spectroscopy, relative densities of sodium and scandium were determined as functions of radius. Using the absolute densities gained from the optical experiment, these relative densities were calibrated. In addition, direct observation of the infrared emission allowed us to characterize the infrared power losses of the lamp. When considered as a fraction of the overall power consumption, the near-infrared spectral power losses were not substantial enough to warrant thorough investigation of their reduction in these lamps. The third project was an attempt to develop a portable x-ray diagnostic experiment. Two-dimensional spatial maps of the lamps were analyzed to determine absolute elemental mercury densities and the arc temperature as a function of radius. Two methods were used to improve the calibration of the density measurements and to correct for the spread in x-ray energy: known solutions of mercury in nitric acid, and an arc lamp which was uniformly heated to evaporate the mercury content. Although many complexities arose in this experiment, its goal was successfully completed.

  17. HIGH INTENSITY EFFECTS IN THE SNS ACCUMULATOR RING

    SciTech Connect

    Holmes, Jeffrey A; Cousineau, Sarah M; Danilov, Viatcheslav; Plum, Michael A; Shishlo, Andrei P

    2008-01-01

    Currently operating at 0.5 MW beam power on target, the Spallation Neutron Source (SNS) is already the world's most powerful pulsed neutron source. However, we are only one third of the way to full power. As we ramp toward full power, the control of the beam and beam loss in the ring will be critical. In addition to practical considerations, such as choice of operating point, painting scheme, RF bunching, and beam scattering, it may be necessary to understand and mitigate collective effects due to space charge, impedances, and electron clouds. At each stage of the power ramp-up, we use all available resources to understand and to minimize beam losses. From the standpoint of beam dynamics, the losses observed so far under normal operating conditions have not involved collective phenomena. We are now entering the intensity regime in which this may change. In dedicated high intensity beam studies, we have already observed resistive wall, extraction kicker impedance-driven, and electron cloud activities. The analysis and simulation of this data are important ongoing activities at SNS. This paper discusses the status of this work, as well as other considerations necessary to the successful full power operation of SNS.

  18. High-intensity photoionization of H sub 2

    SciTech Connect

    Allendorf, S.W.; Szoeke, A.

    1991-05-01

    A tunable, high-intensity picosecond dye laser system has been employed with electron energy analysis to investigate the dynamics of (3+1) resonance-enhanced multiphoton ionization of H{sub 2} via different vibrational levels of its B{sub 1}{Sigma}{sub u}{sup +} and C{sup 1}{Pi}{sub u} electronic states. We observe production of molecular ions in various vibrational levels, with a shift to increased population of lower vibrational states of H{sub 2}{sup +} consistent with the a.c. Stark shift of the correspondingly lower vibrational levels of the C state into resonance with the three- photon energy of the laser. Clear evidence of direct dissociation of H{sub 2} followed by single-photon ionization of the excited H atom is observed as well. Above threshold ionization of these two processes occurs readily. We also find that dissociative ionization is an increasingly important ionization pathway as the wavelength is increased. Finally, we see evidence of a new ionization pathway, which we assign to photoionization into a transient bound state created by the avoided crossing of the first repulsive electronic state of H{sub 2}{sup +}, {vert bar}2p{sigma}{sub u}, n{r angle}, with the single-photon-dressed ground state of H{sub 2}{sup +}, {vert bar}1s{sigma}{sub g},n + 1{r angle}. 6 refs., 2 figs.

  19. Respiration Based Steering for High Intensity Focused Ultrasound Liver Ablation

    PubMed Central

    Holbrook, Andrew B.; Ghanouni, Pejman; Santos, Juan M.; Dumoulin, Charles; Medan, Yoav; Pauly, Kim Butts

    2014-01-01

    Purpose Respiratory motion makes hepatic ablation using high intensity focused ultrasound challenging. Previous HIFU liver treatment had required apnea induced during general anesthesia. We describe and test a system that allows treatment of the liver in the presence of breathing motion. Materials Mapping a signal from an external respiratory bellow to treatment locations within the liver allows the ultrasound transducer to be steered in real time to the target location. Using a moving phantom, three metrics were used to compare static, steered, and unsteered sonications: the area of sonications once a temperature rise of 15°C was achieved, the energy deposition required to reach that temperature, and the average rate of temperature rise during the first 10 seconds of sonication. Steered HIFU in vivo ablations of the porcine liver were also performed and compared to breath-hold ablations. Results For the last phantom metric, all groups were found to be statistically significantly different (p≤0.003). However, in the other two metrics, the static and unsteered sonications were not statistically different (p>0.9999). Steered in vivo HIFU ablations were not statistically significantly different from ablations during breath-holding. Conclusions A system for performing HIFU steering during ablation of the liver with breathing motion is presented and shown to achieve results equivalent to ablation performed with breath-holding. PMID:23460510

  20. Proton shock acceleration using a high contrast high intensity laser

    NASA Astrophysics Data System (ADS)

    Gauthier, Maxence; Roedel, Christian; Kim, Jongjin; Aurand, Bastian; Curry, Chandra; Goede, Sebastian; Propp, Adrienne; Goyon, Clement; Pak, Art; Kerr, Shaun; Ramakrishna, Bhuvanesh; Ruby, John; William, Jackson; Glenzer, Siegfried

    2015-11-01

    Laser-driven proton acceleration is a field of intense research due to the interesting characteristics of this novel particle source including high brightness, high maximum energy, high laminarity, and short duration. Although the ion beam characteristics are promising for many future applications, such as in the medical field or hybrid accelerators, the ion beam generated using TNSA, the acceleration mechanism commonly achieved, still need to be significantly improved. Several new alternative mechanisms have been proposed such as collisionless shock acceleration (CSA) in order to produce a mono-energetic ion beam favorable for those applications. We report the first results of an experiment performed with the TITAN laser system (JLF, LLNL) dedicated to the study of CSA using a high intensity (5x1019W/cm2) high contrast ps laser pulse focused on 55 μm thick CH and CD targets. We show that the proton spectrum generated during the interaction exhibits high-energy mono-energetic features along the laser axis, characteristic of a shock mechanism.

  1. Robotic Assisted Laparoscopic Prostatectomy after High Intensity Focused Ultrasound Failure

    PubMed Central

    Telis, Leon; Jazayeri, Seyed Behzad

    2017-01-01

    Background. Prostate cancer is the most common cancer diagnosed in men. As new focal therapies become more popular in treatment of prostate cancer, failure cases requiring salvage therapy with either surgical or other techniques are being reported. Objective. To report the options in treatment of prostate cancer after recurrence or failure of the primary treatment modality. Methods. We report a salvage robotic assisted laparoscopic radical prostatectomy (RALP) for prostate cancer recurrence following high intensity focused ultrasound treatment (HIFU) in the United States. Results. A 67-year-old man who underwent HIFU treatment for prostate adenocarcinoma 2 years prior was presented with a rising prostate specific antigen of 6.1 ng/mL to our clinic. A biopsy proven recurrent disease in the area of previous treatment documented the failure of treatment. The patient elected to undergo a salvage RALP. The operation time was 159 minutes. The patient was discharged from the hospital on postoperative day 1 with no complications. The catheter was removed on post-op day 10. The patient reserved sexual function and urinary continence. The PSA levels on 6 months' follow-up are undetectable. Conclusions. Salvage RALP is an effective and safe treatment choice for recurrent prostate adenocarcinoma following failed HIFU treatment if operated by an experienced surgeon. PMID:28243479

  2. Inelastic scattering in condensed matter with high intensity Moessbauer radiation

    SciTech Connect

    Yelon, W.B.; Schupp, G.

    1993-02-01

    The QUEGS facility at MURR has produced a number of new results and demonstrated the range of potential applications of high resolution, high intensity Moessbauer scattering. This work has been carried out by both MU and Purdue researchers and includes published results on Na, W, pentadecane, polydimethylsiloxane and other systems, manuscripts submitted on alkali halides (Phys. Rev. B) and accurate Moessbauer lineshape measurements (Phys. Rev. C), and manuscripts in preparation on glycerol, NiAl and Moessbauer spectra obtained by modulating a scattering crystal. Recently, new collaborations have been initiated which will substantially enhance our efforts. These are with W. Steiner (Vienna), G. Coddens (Saclay), and R. D. Taylor (Los Alamos). Steiner is experienced with Fe-57 Moessbauer scattering, while Coddens specializes in quasielastic neutron scattering; both of these areas naturally complement our work. R. D. Taylor has pioneered Moessbauer spectroscopy from the time of its discovery and has already made important contributions to our study of lattice dynamics and superconductivity for lead alloyed with small quantities of tin. At the same time, a significant instrument upgrade is underway, funded in part by the DOE-URIP program.

  3. High intensity ultrasound modified ovalbumin: Structure, interface and gelation properties.

    PubMed

    Xiong, Wenfei; Wang, Yuntao; Zhang, Chunlan; Wan, Jiawei; Shah, Bakht Ramin; Pei, Yaqiong; Zhou, Bin; Li, Jin; Li, Bin

    2016-07-01

    Influence of high intensity ultrasound (HIUS) on the structure and properties of ovalbumin (OVA) were investigated. It was found that the subunits and secondary structure of OVA did not change significantly with HIUS treatment from the electrophoretic patterns and circular dichroism (CD) spectrum. The amount of free sulfhydryl groups increased and intrinsic fluorescence spectra analysis indicated changes in the tertiary structure and partial unfold of OVA after sonication increased. Compared with the untreated OVA, HIUS treatment increased the emulsifying activity and foaming ability, and decreased interface tension (oil-water and air-water interface), which due to the increased surface hydrophobicity and decreased the surface net charge in OVA, while the emulsifying and foaming stability had no remarkable differences. The increased particle size may be attributed to formation of protein aggregates. Moreover, the gelation temperatures of HIUS-treated samples were higher than the untreated OVA according to the temperature sweep model rheology, and this effect was consistent with the increased in surface hydrophobicity for ultrasound treated OVA. These changes in functional properties of OVA would promote its application in food industry. Copyright © 2016 Elsevier B.V. All rights reserved.

  4. Operation of the Proto-MPEX High Intensity Plasma Source

    NASA Astrophysics Data System (ADS)

    Caughman, J. B. O.; Goulding, R. H.; Biewer, T. M.; Bigelow, T. S.; Campbell, I. H.; Diem, S. J.; Martin, E. H.; Pesavento, P. V.; Rapp, J.; Ray, H. B.; Shaw, G. C.; Showers, M. A.; Luo, G.-N.

    2015-11-01

    The Prototype Materials Plasma Experiment (Proto-MPEX) is a linear high-intensity rf plasma source that combines a high-density helicon plasma generator with electron and ion heating sections. It is being used to study the physics of heating over-dense plasmas in a linear configuration. The helicon plasma is produced by coupling 13.56 MHz rf power at levels up to 100 kW. Microwaves at 28 GHz (~ 150 kW) are coupled to the electrons in the over-dense helicon plasma via Electron Bernstein Waves (EBW). Ion cyclotron heating (~ 30 kW) will be via a magnetic beach approach. Plasma diagnostics include Thomson Scattering and a retarding field energy analyzer near the target, while a microwave interferometer and double-Langmuir probes are used to determine plasma parameters elsewhere in the system. Filterscopes are being used to measure D-alpha emission and He line ratios at multiple locations, and IR cameras image the target plates to determine heat deposition. High plasma densities in the helicon region have been produced in He (>3x1019/m3) and D (>1.5x1019/m3) , and operation with on-axis magnetic field strength >1 T has been demonstrated. Details of the experimental results and future plans for studying plasma surface/RF antenna interactions will be presented. ORNL is managed by UT-Battelle, LLC, for the U.S. DOE under contract DE-AC-05-00OR22725.

  5. High-intensity positron microprobe at Jefferson Lab

    SciTech Connect

    Golge, Serkan; Vlahovic, Branislav; Wojtsekhowski, Bogdan B.

    2014-06-19

    We present a conceptual design for a novel continuous wave electron-linac based high-intensity slow-positron production source with a projected intensity on the order of 1010 e+/s. Reaching this intensity in our design relies on the transport of positrons (T+ below 600 keV) from the electron-positron pair production converter target to a low-radiation and low-temperature area for moderation in a high-efficiency cryogenic rare gas moderator, solid Ne. The performance of the integrated beamline has been verified through computational studies. The computational results include Monte Carlo calculations of the optimized electron/positron beam energies, converter target thickness, synchronized raster system, transport of the beam from the converter target to the moderator, extraction of the beam from the channel, and moderation efficiency calculations. For the extraction of positrons from the magnetic channel a magnetic field terminator plug prototype has been built and experimental data on the effectiveness of this prototype are presented. The dissipation of the heat away from the converter target and radiation protection measures are also discussed.

  6. High-intensity positron microprobe at Jefferson Lab

    DOE PAGES

    Golge, Serkan; Vlahovic, Branislav; Wojtsekhowski, Bogdan B.

    2014-06-19

    We present a conceptual design for a novel continuous wave electron-linac based high-intensity slow-positron production source with a projected intensity on the order of 1010 e+/s. Reaching this intensity in our design relies on the transport of positrons (T+ below 600 keV) from the electron-positron pair production converter target to a low-radiation and low-temperature area for moderation in a high-efficiency cryogenic rare gas moderator, solid Ne. The performance of the integrated beamline has been verified through computational studies. The computational results include Monte Carlo calculations of the optimized electron/positron beam energies, converter target thickness, synchronized raster system, transport of themore » beam from the converter target to the moderator, extraction of the beam from the channel, and moderation efficiency calculations. For the extraction of positrons from the magnetic channel a magnetic field terminator plug prototype has been built and experimental data on the effectiveness of this prototype are presented. The dissipation of the heat away from the converter target and radiation protection measures are also discussed.« less

  7. The WARP Code: Modeling High Intensity Ion Beams

    SciTech Connect

    Grote, D P; Friedman, A; Vay, J L; Haber, I

    2004-12-09

    The Warp code, developed for heavy-ion driven inertial fusion energy studies, is used to model high intensity ion (and electron) beams. Significant capability has been incorporated in Warp, allowing nearly all sections of an accelerator to be modeled, beginning with the source. Warp has as its core an explicit, three-dimensional, particle-in-cell model. Alongside this is a rich set of tools for describing the applied fields of the accelerator lattice, and embedded conducting surfaces (which are captured at sub-grid resolution). Also incorporated are models with reduced dimensionality: an axisymmetric model and a transverse ''slice'' model. The code takes advantage of modern programming techniques, including object orientation, parallelism, and scripting (via Python). It is at the forefront in the use of the computational technique of adaptive mesh refinement, which has been particularly successful in the area of diode and injector modeling, both steady-state and time-dependent. In the presentation, some of the major aspects of Warp will be overviewed, especially those that could be useful in modeling ECR sources. Warp has been benchmarked against both theory and experiment. Recent results will be presented showing good agreement of Warp with experimental results from the STS500 injector test stand. Additional information can be found on the web page http://hif.lbl.gov/theory/WARP{_}summary.html.

  8. The WARP Code: Modeling High Intensity Ion Beams

    SciTech Connect

    Grote, David P.; Friedman, Alex; Vay, Jean-Luc; Haber, Irving

    2005-03-15

    The Warp code, developed for heavy-ion driven inertial fusion energy studies, is used to model high intensity ion (and electron) beams. Significant capability has been incorporated in Warp, allowing nearly all sections of an accelerator to be modeled, beginning with the source. Warp has as its core an explicit, three-dimensional, particle-in-cell model. Alongside this is a rich set of tools for describing the applied fields of the accelerator lattice, and embedded conducting surfaces (which are captured at sub-grid resolution). Also incorporated are models with reduced dimensionality: an axisymmetric model and a transverse 'slice' model. The code takes advantage of modern programming techniques, including object orientation, parallelism, and scripting (via Python). It is at the forefront in the use of the computational technique of adaptive mesh refinement, which has been particularly successful in the area of diode and injector modeling, both steady-state and time-dependent. In the presentation, some of the major aspects of Warp will be overviewed, especially those that could be useful in modeling ECR sources. Warp has been benchmarked against both theory and experiment. Recent results will be presented showing good agreement of Warp with experimental results from the STS500 injector test stand. Additional information can be found on the web page http://hif.lbl.gov/theory/WARP{sub s}ummary.html.

  9. Repeated high-intensity exercise in a professional rugby league.

    PubMed

    Austin, Damien J; Gabbett, Tim J; Jenkins, David J

    2011-07-01

    The primary aim of this study was to identify and describe the frequency and duration of repeated high-intensity exercise (RHIE) bouts in Australian professional rugby league (National Rugby League) and whether these occurred at critical times during a game. Time motion analysis was used during 5 competition matches; 1 player from 3 positional groups (hit-up forward, adjustable, and outside back) was analyzed in each match. The ranges of RHIE bouts for the 3 positional groups were hit-up forwards 9-17, adjustables 2-8, and outside backs 3-7. Hit-up forwards were involved in a significantly greater number of RHIE bouts (p < 0.05) and had the shortest average recovery (376 ± 205 seconds) between RHIE bouts. The single overall maximum durations of RHIE bouts for the hit-up forwards, the adjustables, and the outside backs were 64, 64, and 49 seconds. For all groups, 70% of the total RHIE bouts occurred within 5 minutes prior of a try being scored. The present data show that the nature of RHIE bouts was specific to playing position and occurred frequently at critical times during the game. These results can be used to develop training programs that mimic the 'worst case scenarios' that elite rugby league players are likely to encounter.

  10. Multifunctional pulse generator for high-intensity focused ultrasound system

    NASA Astrophysics Data System (ADS)

    Tamano, Satoshi; Yoshizawa, Shin; Umemura, Shin-Ichiro

    2017-07-01

    High-intensity focused ultrasound (HIFU) can achieve high spatial resolution for the treatment of diseases. A major technical challenge in implementing a HIFU therapeutic system is to generate high-voltage high-current signals for effectively exciting a multichannel HIFU transducer at high efficiencies. In this paper, we present the development of a multifunctional multichannel generator/driver. The generator can produce a long burst as well as an extremely high-voltage short pulse of pseudosinusoidal waves (trigger HIFU) and second-harmonic superimposed waves for HIFU transmission. The transmission timing, waveform, and frequency can be controlled using a field-programmable gate array (FPGA) via a universal serial bus (USB) microcontroller. The hardware is implemented in a compact printed circuit board. The test results of trigger HIFU reveal that the power consumption and the temperature rise of metal-oxide semiconductor field-effect transistors were reduced by 19.9% and 38.2 °C, respectively, from the previous design. The highly flexible performance of the novel generator/driver is demonstrated in the generation of second-harmonic superimposed waves, which is useful for cavitation-enhanced HIFU treatment, although the previous design exhibited difficulty in generating it.

  11. A methodology for assessing high intensity RF effects in aircraft

    SciTech Connect

    Zacharias, R.A.; Avalle, C.A.; Kunz, K.S.; Molau, N.E.; Pennock, S.T.; Poggio, A.J.; Sharpe, R.M.

    1993-07-01

    Optical components have an inherent immunity to the electromagnetic interference (EMI) associated with High Intensity Radiated Fields (HIRF). The optical technology embodied in Fly-by-Light (FBL) might therefore minimize the effects of HIRF on digitally controlled systems while providing lifetime immunity to signal EMI. This is one of the primary motivations for developing FBL systems for aircraft. FBL has the potential to greatly simplify EMI certification by enabling technically acceptable laboratory tests of subsystems, as opposed to expensive full airplane tests. In this paper the authors describe a methodology for assessing EMI effects on FBL aircraft that reduces or potentially eliminates the need for full airplane tests. This methodology is based on comparing the applied EMI stress--the level of interference signal that arrives at a unit under test--versus the EMI strength of the unit--the interference level it can withstand without upset. This approach allows one to use computer models and/or low power coupling measurement and similarity (to other previously tested aircraft) to determine the stress applied to installed subsystems, and to use benchtop cable injection tests and/or mode stirred chamber radiated tests to determine the strength of the subsystem.

  12. Free-field propagation of high intensity noise. [supersonic jets

    NASA Technical Reports Server (NTRS)

    Mcdaniel, O. H.; Roth, S. D.; Welz, J. P.

    1981-01-01

    Research on high intensity (finite amplitude) acoustic waves shows that nonlinear distortion effects generally result in a shift of energy to higher frequencies. The higher intensities associated with supersonic jets would therefore indicate that high frequency enhancement of the spectrum should occur, resulting in the differences observed between subsonic and supersonic jets. A 10,000 acoustic watt source installed in an anechoic chamber generates sound levels such that acoustic shocks are readily observable. Dual frequency excitation of the source produces a strong parametric effect with a difference frequency comparable in level to the primary frequency. The test set up and recording equipment being used to determine the finite amplitude noise representative of an actual supersonic jet are described as well as the development of a computer program based on Burger's equation. The spectra of 1/2 octave band, 1 kHz sine wave, and dual frequency input and output are presented in graphs along with waveforms at Z = .025, 0.1, and 1.0.

  13. Particle Simulation Schemes for High Intensity Charged Particle Beams

    NASA Astrophysics Data System (ADS)

    Lee, Wei-Li; Startsev, Edward; Qin, Hong; Davidson, Ronald C.

    2003-10-01

    Numerical schemes for the electromagnetic particle simulations of high intensity charged particle beams have been developed. The purpose of devising these schemes is to avoid the numerical difficulties associated with the direct calculation of the time derivatives of the vector potential, partial A / partial t, in the Darwin model, for which the transverse induction current in Ampere's law is neglected. The first scheme requires the calculations of higher order velocity moments of the distribution function to obtain the time derivatives for both the scalar potential Φ and A, similar to the method used for shear-Alfven waves.[1] The second uses the canonical momentum P = p + q A/c in the equations of motion as a means to eliminate the troublesome time derivatives.[2] The use of these schemes for physics problems in heavy ion fusion systems will be reported. [1] W. W. Lee, J. L. V. Lewandowski, T. S. Hahm, and Z. Lin, Phys. Plasmas 8, 4435 (2001). [2] W. W. Lee, E. Startsev, H. Qin and R. C. Davidson, Proceedings of 2001 Particle Accelerator Conference 1906 (2001).

  14. High intensity laser beam propagation through a relativistic warm magnetoplasma

    NASA Astrophysics Data System (ADS)

    Rezaei, S.; Jafari Milani, M. R.; Jafari, M. J.

    2017-04-01

    In this work, nonlinear aspects of a circularly polarized high intensity Gaussian laser beam propagating in a relativistic warm magnetized plasma are studied, taking into account the relativistic ponderomotive force. The differential equation governing the dimensionless beam width parameter is achieved and numerically solved by introducing the dielectric permittivity of such plasma and using the paraxial ray approximation. The effects of entrance laser intensity and its polarization state, external magnetic field, and electron temperature on the laser spot size evolution are studied. It is found that for both right and left-handed polarization states increasing initial laser intensity deteriorates the self-focusing mechanism while rising electron temperature improves it. It is also observed that enhancing magnetic field leads to faster and stronger self-focusing in the case of right-handed polarization and an attenuation in the self-focusing process in the case of left-handed one. In addition, the spatial distribution of normalized modified electron density as well as laser intensity profiles as a function of plasma length and beam radius is plotted and discussed for three self-focusing, self-trapping, and defocusing regimes.

  15. Ablation of tissue volumes using high intensity focused ultrasound.

    PubMed

    Malcolm, A L; ter Haar, G R

    1996-01-01

    Successful application of high intensity focused ultrasound to cancer treatment requires complete ablation of tissue volumes. In order to destroy an entire tumour it is necessary to place a contiguous array of touching lesions throughout it. In a study of how best to achieve this, exposures were selected to give single lesions that were thermal in origin, while avoiding effects due to tissue water boiling and acoustic cavitation. Arrays were formed in excised bovine liver. Under some exposure conditions, lesions were found to merge in front of the focal point, and failed to cover the desired volume. Using fine wire manganin-constantan thermocouples, temperature studies revealed a substantial rise in the temperature of surrounding untreated tissue. Cooling curves showed that it was necessary to allow surrounding tissue to cool for up to 2 min before ambient temperature was reached. By allowing the tissue to cool between exposures it was possible to form arrays of overlapping lesions thus successfully ablating the complete target region.

  16. Blood coagulation using High Intensity Focused Ultrasound (HIFU)

    NASA Astrophysics Data System (ADS)

    Nguyen, Phuc V.; Oh, Junghwan; Kang, Hyun Wook

    2014-03-01

    High Intensity Focused Ultrasound (HIFU) technology provides a feasible method of achieving thermal coagulation during surgical procedures. One of the potential clinical benefits of HIFU can induce immediate hemostasis without suturing. The objective of this study was to investigate the efficiency of a HIFU system for blood coagulation on severe vascular injury. ngHIFU treatment was implemented immediately after bleeding in artery. The ultrasound probe was made of piezoelectric material, generating a central frequency of 2.0 MHz as well as an ellipsoidal focal spot of 2 mm in lateral dimension and 10 mm in axial dimension. Acoustic coagulation was employed on a perfused chicken artery model in vitro. A surgical incision (1 to 2 mm long) was made with a scapel on the arterial wall, and heparinized autologous blood was made to leak out from the incision with a syringe pump. A total of 5 femoral artery incisions was treated with the HIFU beam. The intensity of 4500 W/cm2 at the focus was applied for all treatments. Complete hemostasis was achieved in all treatments, along with the treatment times of 25 to 50 seconds. The estimated intraoperative blood loss was from 2 to 5 mL. The proposed HIFU system may provide an effective method for immediate blood coagulation for arteries and veins in clinical applications.

  17. Formation of a high intensity low energy positron string

    NASA Astrophysics Data System (ADS)

    Donets, E. D.; Donets, E. E.; Syresin, E. M.; Itahashi, T.; Dubinov, A. E.

    2004-05-01

    The possibility of a high intensity low energy positron beam production is discussed. The proposed Positron String Trap (PST) is based on the principles and technology of the Electron String Ion Source (ESIS) developed in JINR during the last decade. A linear version of ESIS has been used successfully for the production of intense highly charged ion beams of various elements. Now the Tubular Electron String Ion Source (TESIS) concept is under study and this opens really new promising possibilities in physics and technology. In this report, we discuss the application of the tubular-type trap for the storage of positrons cooled to the cryogenic temperatures of 0.05 meV. It is intended that the positron flux at the energy of 1-5 eV, produced by the external source, is injected into the Tubular Positron Trap which has a similar construction as the TESIS. Then the low energy positrons are captured in the PST Penning trap and are cooled down because of their synchrotron radiation in the strong (5-10 T) applied magnetic field. It is expected that the proposed PST should permit storing and cooling to cryogenic temperature of up to 5×109 positrons. The accumulated cooled positrons can be used further for various physics applications, for example, antihydrogen production.

  18. High Intensity Focused Ultrasound Tumor Therapy System and Its Application

    NASA Astrophysics Data System (ADS)

    Sun, Fucheng; He, Ye; Li, Rui

    2007-05-01

    At the end of last century, a High Intensity Focused Ultrasound (HIFU) tumor therapy system was successfully developed and manufactured in China, which has been already applied to clinical therapy. This article aims to discuss the HIFU therapy system and its application. Detailed research includes the following: power amplifiers for high-power ultrasound, ultrasound transducers with large apertures, accurate 3-D mechanical drives, a software control system (both high-voltage control and low-voltage control), and the B-mode ultrasonic diagnostic equipment used for treatment monitoring. Research on the dosage of ultrasound required for tumour therapy in multiple human cases has made it possible to relate a dosage formula, presented in this paper, to other significant parameters such as the volume of thermal tumor solidification, the acoustic intensity (I), and the ultrasound emission time (tn). Moreover, the HIFU therapy system can be applied to the clinical treatment of both benign and malignant tumors in the pelvic and abdominal cavity, such as uterine fibroids, liver cancer and pancreatic carcinoma.

  19. High-intensity Exercise in Men with Type 1 Diabetes and Mode of Insulin Therapy.

    PubMed

    Gawrecki, Andrzej; Naskret, Dariusz; Niedzwiecki, Pawel; Duda-Sobczak, Anna; Araszkiewicz, Aleksandra; Zozulinska-Ziolkiewicz, Dorota

    2017-04-01

    The purpose of this study was to evaluate the impact of high intensity exercise on glucose levels and risk of metabolic decompensation in males with type 1 diabetes (T1D), depending on the method of insulin administration. The study comprised 29 males (aged 25.3±5.1 years; duration of diabetes 10.3±3.2 years) treated with continuous subcutaneous insulin infusion (CSII) or multiple daily insulin injections (MDI). Treadmill exercise test was performed twice in each patient until subjective exhaustion as maximum according to the Borg scale. All the patients achieved ≥85% of the maximal heart rate. Distance during the test was 4 500±1 400 m and 4 473±1 559 m in the MDI and CSII groups, respectively, which was achieved in 31±8 min. During the test and in the 6 h after, no clinically significant episodes of hypoglycemia occurred. Mean glucose levels did not exceed 10 mmol/L in most patients. The risk of the composite endpoint (hypoglycemia<3.8 mmol/L, hyperglycemia≥16.6 mmol/L, ketones≥0.6 mmol/L, and lactate>2.2 mmol/L) was higher in patients treated with MDI than CSII (OR3.75, 95%CI:1.22-11.52, p=0.02). In conclusion, planned high intensity physical effort in men with well-controlled T1D is metabolically safe. CSII shows greater metabolic advantage over MDI during and after high intensity exercise in men with T1D. © Georg Thieme Verlag KG Stuttgart · New York.

  20. The effect of recombinant human fibroblast growth factor-18 on articular cartilage following single impact load.

    PubMed

    Barr, Lynne; Getgood, Alan; Guehring, Hans; Rushton, Neil; Henson, Frances M D

    2014-07-01

    The aim of this in vitro study was to ascertain the effect of recombinant human Fibroblast Growth Factor-18 (rhFGF18) on the repair response of mechanically damaged articular cartilage. Articular cartilage discs were harvested from healthy mature horses (n = 4) and subjected to single impact load (SIL). The impacted explants, together with unimpacted controls were cultured in modified DMEM ± 200 ng/ml rhFGF18 for up to 30 days. Glycosaminoglycan (GAG) release into the media was measured using the dimethylmethylene blue (DMMB) assay. Aggrecan neopepitope CS846, collagen type II synthesis (CPII) and cleavage (C2C) were measured by ELISA. Histological analysis and TUNEL staining were used to assess repair cell number and cell death. Impacted explants treated with rhFGF18 showed significantly more GAG and CS846 release into the media (p < 0.05), there was also a significant decrease in C2C levels at Day 20. Loaded sections treated with rhFGF18 had more repair cells and significantly less cell death (p < 0.001) at Day 30 in culture. In an in vitro damage/repair model, rhFGF18 increases the proteoglycan synthesis, the repair cell number and prevents apoptosis at Day 30. This suggests that rhFGF18 may be a good candidate for enhancement of cartilage repair following mechanical damage. © 2014 Orthopaedic Research Society. Published by Wiley Periodicals, Inc.

  1. Effect of High Impact or Non-impact Loading Activity on Bone Bending Stiffness and Mineral Density

    NASA Technical Reports Server (NTRS)

    Liang, Michael T. C.; Arnnud, Sara B.; Steele, Charles R.; Moreno, Alexjandro

    2003-01-01

    Material properties of conical bone, including mineral density (BMD) and its geometry is closely related to its load-carrying capacity. These two primary components determine the strength of conical bone. High impact loading involving acceleration and deceleration movements used in gymnastics induce higher BMD of the affected bone compared to the non-impact acceleration and deceleration movements used in swimming. Study of these two groups of athletes on bone bending stiffness has not been reported. The purpose of this study was to compare differences in bone bending stiffness and BMD between competitive female synchronized swimmers and female gymnasts. Thirteen world class female synchronized swimmers (SYN) and 8 female gymnasts (GYM), mean age 21 +/- 2.9 yr. were recruited for this study. We used a mechanical response tissue analyzer (Gaitscan, NJ) to calculate EI, where E is Young's modulus of elasticity and I is the cross-sectional moment of inertia. EI was obtained from tissue response to a vibration probe placed directly on the skin of the mid-region of tibia and ulna. BMD of the heel and wrist were measured with a probe densitometer (PIXI, Lunor, WI). The SYN were taller than (p < 0.05) the GYM but weighed the same as the GYM. EI obtained from tibia and ulna of the SYN (291 +/- 159 and 41 +/- 19.4, respectively) were not significantly different from thc GYM (285 +/- 140 and 44 +/- 18.3, respectively). BMD of the heel and wrist in GYM were higher than in SYN (p < 0.001). High impact weight-bearing activities promote similar bone strength but greater BMD response than non-impact activities performed in a buoyant environment.

  2. Effect of High Impact or Non-impact Loading Activity on Bone Bending Stiffness and Mineral Density

    NASA Technical Reports Server (NTRS)

    Liang, Michael T. C.; Arnnud, Sara B.; Steele, Charles R.; Moreno, Alexjandro

    2003-01-01

    Material properties of conical bone, including mineral density (BMD) and its geometry is closely related to its load-carrying capacity. These two primary components determine the strength of conical bone. High impact loading involving acceleration and deceleration movements used in gymnastics induce higher BMD of the affected bone compared to the non-impact acceleration and deceleration movements used in swimming. Study of these two groups of athletes on bone bending stiffness has not been reported. The purpose of this study was to compare differences in bone bending stiffness and BMD between competitive female synchronized swimmers and female gymnasts. Thirteen world class female synchronized swimmers (SYN) and 8 female gymnasts (GYM), mean age 21 +/- 2.9 yr. were recruited for this study. We used a mechanical response tissue analyzer (Gaitscan, NJ) to calculate EI, where E is Young's modulus of elasticity and I is the cross-sectional moment of inertia. EI was obtained from tissue response to a vibration probe placed directly on the skin of the mid-region of tibia and ulna. BMD of the heel and wrist were measured with a probe densitometer (PIXI, Lunor, WI). The SYN were taller than (p < 0.05) the GYM but weighed the same as the GYM. EI obtained from tibia and ulna of the SYN (291 +/- 159 and 41 +/- 19.4, respectively) were not significantly different from thc GYM (285 +/- 140 and 44 +/- 18.3, respectively). BMD of the heel and wrist in GYM were higher than in SYN (p < 0.001). High impact weight-bearing activities promote similar bone strength but greater BMD response than non-impact activities performed in a buoyant environment.

  3. Prediction and Analysis of Material Response to Impact and Shock Loading Using a Sharp-Interface Eulerian Methodology

    DTIC Science & Technology

    2005-12-01

    IMPACT AND 5b. GRANT NUMBER SHOCK LOADING USING A SHARP-INTERFACE EULERIAN METHODOLOGY 5c. PROGRAM ELEMENT NUMBER 6. AUTHOR(S) 5d. PROJECT NUMBER H. S...ABSTRACT Numerical methods and a computer code have been developed for the simulation of multimaterial interactions in a general setting...by ANSI Std. Z39.18 FINAL REPORT PREDICTION AND ANALYSIS OF MATERIAL RESPONSE TO IMPACT AND SHOCK LOADING USING A SHARP-INTERFACE EULERIAN METHODOLOGY

  4. Modeling the impacts of alternative fertilization methods on nitrogen loading in rice production in Shanghai.

    PubMed

    Zhao, Zheng; Sha, Zhimin; Liu, Yibo; Wu, Shuhang; Zhang, Hanlin; Li, Changsheng; Zhao, Qi; Cao, Linkui

    2016-10-01

    Nitrogen (N) loss from paddy fields is an important source of agricultural non-point source pollution that leads to eutrophication of water bodies and degradation of water quality. The impacts of alternative N fertilizer management practices on N loading (N loss through runoff and leaching) from paddy fields in Shanghai were assessed using a process-based biogeochemical model, DNDC. The results indicated that the current fertilization rate in paddy fields of Shanghai (300kgN/ha) exceeds the actual rice demand and has led to substantial N loading of 1142±276kg. The combined application of urea at 150kgN/ha and organic manure at 100kgN/ha was identified as the best fertilization method for rice cultivation in Shanghai; this application maintained optimal rice yields and significantly reduced N loading to 714±151kg in comparison with the current fertilization rate. A sensitivity test was conducted with various input parameters, and the results indicated that fertilization, precipitation and soil properties were the most sensitive factors that regulate N loss from paddy fields. The variability of soil properties, especially SOC led to high uncertainties in the simulated results. Therefore, the local climate conditions and soil properties should be taken into account in the identification of the best management practice (BMP) for rice cultivation, given the high spatially heterogeneous N loading values across all towns used in the simulation. The DNDC model is an effective approach for simulating and predicting N loading in paddy fields under alternative agricultural management practices.

  5. Impact of Paint Color on Rest Period Climate Control Loads in Long-Haul Trucks: Preprint

    SciTech Connect

    Lustbader, J.; Kreutzer, C.; Jeffers, M.; Adelman, S.; Yeakel, S.; Brontz, P.; Olson, K.; Ohlinger, J.

    2014-02-01

    Cab climate conditioning is one of the primary reasons for operating the main engine in a long-haul truck during driver rest periods. In the United States, sleeper cab trucks use approximately 667 million gallons of fuel annually for rest period idling. The U.S. Department of Energy's National Renewable Energy Laboratory's (NREL) CoolCab Project works closely with industry to design efficient thermal management systems for long-haul trucks that minimize engine idling and fuel use while maintaining occupant comfort. Heat transfer to the vehicle interior from opaque exterior surfaces is one of the major heat pathways that contribute to air conditioning loads during long-haul truck daytime rest period idling. To quantify the impact of paint color and the opportunity for advanced paints, NREL collaborated with Volvo Group North America, PPG Industries, and Dometic Environmental Corporation. Initial screening simulations using CoolCalc, NREL's rapid HVAC load estimation tool, showed promising air-conditioning load reductions due to paint color selection. Tests conducted at NREL's Vehicle Testing and Integration Facility using long-haul truck cab sections, 'test bucks,' showed a 31.1% of maximum possible reduction in rise over ambient temperature and a 20.8% reduction in daily electric air conditioning energy use by switching from black to white paint. Additionally, changing from blue to an advanced color-matched solar reflective blue paint resulted in a 7.3% reduction in daily electric air conditioning energy use for weather conditions tested in Colorado. National-level modeling results using weather data from major U.S. cities indicated that the increase in heating loads due to lighter paint colors is much smaller than the reduction in cooling loads.

  6. Impact of fungal load on diagnosis and outcome of allergic fungal rhinosinusitis.

    PubMed

    Ragab, Ahmed; Samaka, Rehab Monir; Salem, Mohamed

    2014-01-01

    Fungal load colonization may modify the classic eosinophilic inflammation in allergic fungal rhinosinusitis (AFRS). We aimed to evaluate the impact of fungal load on diagnosis and outcome of AFRS. In the present cohort study fungal load differences were determined prospectively according to Gomori methenamine silver (GMS) fungal stained (histopathological and cytological examination) with the tenacious mucus, cheesy clay-like materials and sinus mucosa/polyps in 12 AFRS patients. Two groups with different fungal loads, AFRS with (six patients) and without (six patients) high fungal loads (HFL) were evaluated for nasal endoscopic score, paranasal sinuses CT score, histopathological and immunohistochemical changes. Endoscopic outcome scoring differences were evaluated for 1 year after endoscopic sinus surgery and 1 month oral corticosteroids treatment. No differences were observed between both groups (AFRS with/without HFL) concerning the total CT score and opacification features (P > 0.05). Eosinophils and CD3 + CD8 + T cell were dominant in both groups. More edema and less fibrosis were observed in HFL group. Gliotoxin producers Aspergilli were present in all HFL in comparison to 5/6 (83.3%) in cases without HFL. Fewer patients 1/6 (16.6%) and less number of recurrences/year 0.1 ± 0.4 occurred in the AFRS with HFL compared to the AFRS without HFL [5/6 (83.3%) and 1.16 ± 0.7) (P = 0.021 and 0.023, respectively]. In addition to mucus and mucosal tissues, cheesy clay-like materials must be assessed in AFRS cases. Although patients of AFRS with HFL had negligible clinical differences from ordinary AFRS without HFL, they had better outcome after treatment.

  7. Pleiotropic Impact of Endosymbiont Load and Co-Occurrence in the Maize Weevil Sitophilus zeamais

    PubMed Central

    Carvalho, Gislaine A.; Vieira, Juliana L.; Haro, Marcelo M.; Corrêa, Alberto S.; Ribon, Andrea Oliveira B.; de Oliveira, Luiz Orlando; Guedes, Raul Narciso C.

    2014-01-01

    Individual traits vary among and within populations, and the co-occurrence of different endosymbiont species within a host may take place under varying endosymbiont loads in each individual host. This makes the recognition of the potential impact of such endosymbiont associations in insect species difficult, particularly in insect pest species. The maize weevil, Sitophilus zeamais Motsch. (Coleoptera: Curculionidae), a key pest species of stored cereal grains, exhibits associations with two endosymbiotic bacteria: the obligatory endosymbiont SZPE (“Sitophilus zeamais Primary Endosymbiont”) and the facultative endosymbiont Wolbachia. The impact of the lack of SZPE in maize weevil physiology is the impairment of nutrient acquisition and energy metabolism, while Wolbachia is an important factor in reproductive incompatibility. However, the role of endosymbiont load and co-occurrence in insect behavior, grain consumption, body mass and subsequent reproductive factors has not yet been explored. Here we report on the impacts of co-occurrence and varying endosymbiont loads achieved via thermal treatment and antibiotic provision via ingested water in the maize weevil. SZPE exhibited strong effects on respiration rate, grain consumption and weevil body mass, with observed effects on weevil behavior, particularly flight activity, and potential consequences for the management of this pest species. Wolbachia directly favored weevil fertility and exhibited only mild indirect effects, usually enhancing the SZPE effect. SZPE suppression delayed weevil emergence, which reduced the insect population growth rate, and the thermal inactivation of both symbionts prevented insect reproduction. Such findings are likely important for strain divergences reported in the maize weevil and their control, aspects still deserving future attention. PMID:25347417

  8. The Impact of Water Loading on Estimates of Postglacial Decay Times in Hudson Bay

    NASA Astrophysics Data System (ADS)

    Han, H. K.; Gomez, N. A.

    2016-12-01

    Ongoing glacial isostatic adjustment (GIA) due to surface loading (ice and water) variations since the Last Glacial Maximum (LGM) has been contributing to sea level changes globally throughout the Holocene, especially in regions like the Canada that were heavily glaciated during the LGM. The spatial and temporal distribution of GIA and relative sea level change are attributed to the ice history and the rheological structure of the solid Earth, both of which are uncertain. It has been shown that relative sea level curves in previously glaciated regions follow an exponential-like form, and the post glacial decay times associated with that form have weak sensitivity to the details of the ice loading history (Andrews 1970, Walcott 1980, Mitrovica & Peltier 1995). Post glacial decay time estimates may therefore be used to constrain the Earth's structure and improve GIA predictions. However, estimates of decay times in Hudson Bay in the literature differ significantly due to a number of sources of uncertainty and bias (Mitrovica et al. 2000). Previous decay time analyses have not considered the potential bias that surface loading associated with Holocene sea level changes can introduce in decay time estimates derived from nearby relative sea level observations. We explore the spatial patterns of post glacial decay time predictions in previously glaciated regions, and their sensitivity to ice and water loading history. We compute post glacial sea level changes over the last deglaciation from 21ka to the modern associated with the ICE5G (Peltier, 2004) and ICE6G (Argus et al. 2014, Peltier et al. 2015) ice history models. We fit exponential curves to the modeled relative sea level changes, and compute maps of post glacial decay time predictions across North America and the Arctic. In addition, we decompose the modeled relative sea level changes into contributions from water and ice loading effects, and compute the impact of water loading redistribution since the LGM on

  9. Impact Load Behavior between Different Charge and Lifter in a Laboratory-Scale Mill

    PubMed Central

    Yin, Zixin; Zhu, Zhencai; Yu, Zhangfa; Li, Tongqing

    2017-01-01

    The impact behavior between the charge and lifter has significant effect to address the mill processing, and is affected by various factors including mill speed, mill filling, lifter height and media shape. To investigate the multi-body impact load behavior, a series of experiments and Discrete Element Method (DEM) simulations were performed on a laboratory-scale mill, in order to improve the grinding efficiency and prolong the life of the lifter. DEM simulation hitherto has been extensively applied as a leading tool to describe diverse issues in granular processes. The research results shown as follows: The semi-empirical power draw of Bond model in this paper does not apply very satisfactorily for the ball mills, while the power draw determined by DEM simulation show a good approximation for the measured power draw. Besides, the impact force on the lifter was affected by mill speed, grinding media filling, lifter height and iron ore particle. The maximum percent of the impact force between 600 and 1400 N is at 70–80% of critical speed. The impact force can be only above 1400 N at the grinding media filling of 20%, and the maximum percent of impact force between 200 and 1400 N is obtained at the grinding media filling of 20%. The percent of impact force ranging from 0 to 200 N decreases with the increase of lifter height. However, this perfect will increase above 200 N. The impact force will decrease when the iron ore particles are added. Additionally, for the 80% of critical speed, the measured power draw has a maximum value. Increasing the grinding media filling increases the power draw and increasing the lifter height does not lead to any variation in power draw. PMID:28773243

  10. Shear fracture of jointed steel plates of bolted joints under impact load

    NASA Astrophysics Data System (ADS)

    Daimaruya, M.; Fujiki, H.; Ambarita, H.; Kobayashi, H.; Shin, H.-S.

    2013-07-01

    The present study is concerned with the development of a fracture criterion for the impact fracture of jointed steel plates of bolted joints used in a car body, which contributes to crash simulations by CAE. We focus our attention on the shear fracture of the jointed steel plates of lap-bolted joints in the suspension of a car under impact load. Members of lap-bolted joints are modelled as a pair of steel plates connected by a bolt. One of the plates is a specimen subjected to plastic deformation and fracture and the other is a jig subjected to elastic deformation only. Three kinds of steel plate specimens are examined, i.e., a common steel plate with a tensile strength of 270 MPa and high tensile strength steel plates of 440 and 590 MPa used for cars. The impact shear test was performed using the split Hopkinson bar technique for tension impact, together with the static test using a universal testing machine INSTRON 5586. The behaviour of the shear stress and deformation up to rupture taking place in the joint was discussed. The obtained results suggest that a stress-based fracture criterion may be developed for the impact fracture of jointed steel plates of a lap-bolted joint.

  11. High intensity ultrasound transducer used in gene transfection

    NASA Astrophysics Data System (ADS)

    Morrison, Kyle P.; Keilman, George W.; Noble, Misty L.; Brayman, Andrew A.; Miao, Carol H.

    2012-11-01

    This paper describes a novel therapeutic high intensity non-focused ultrasound (HIU) transducer designed with uniform pressure distribution to aid in accelerated gene transfer in large animal liver tissues in vivo. The underlying HIU transducer was used to initiate homogeneous cavitation throughout the tissue while delivering up to 2.7 MPa at 1.1 MHz across its radiating surface. The HIU transducer was built into a 6 cm diameter x 1.3 cm tall housing ergonomically designed to avoid collateral damage to the surrounding anatomy during dynamic motion. The ultrasound (US) radiation was applied in a 'paintbrush-like' manner to the surface of the liver. The layers and geometry of the transducer were carefully selected to maximize the active diameter (5.74 cm), maximize the electrical to acoustic conversion efficiency (85%) to achieve 2.7 MPa of peak negative pressure, maximize the frequency operating band at the fundamental resonance to within a power transfer delta of 1 dB, and reduce the pressure delta to within 2 dB across the radiating surface. For maximum peak voltage into the transducer, a high performance piezoceramic was chosen and a DC bias circuit was built integral to the system. An apodized two element annular pattern was made from a single piezoceramic element, resulting in significant pressure uniformity enhancement. In addition to using apodization for pressure uniformity, a proprietary multi-layered structure was used to improve efficiency while sustaining an operating band from 900 kHz to 1.3 MHz. The resultant operating band allowed for dithering techniques using frequency modulation. The underlying HIU transducer for use in large animals enhances gene expression up to 6300-fold.

  12. Compliance with High-Intensity Radiated Fields Regulations - Emitter's Perspective

    NASA Technical Reports Server (NTRS)

    Statman, Joseph; Jamnejad, Vahraz; Nguyen, Lee

    2012-01-01

    NASA's Deep Space Network (DSN) uses high-power transmitters on its large antennas to communicate with spacecraft of NASA and its partner agencies. The prime reflectors of the DSN antennas are parabolic, at 34m and 70m in diameter. The DSN transmitters radiate Continuous Wave (CW) signals at 20 kW - 500 kW at X-band and S-band frequencies. The combination of antenna reflector size and high frequency results in a very narrow beam with extensive oscillating near-field pattern. Another unique feature of the DSN antennas is that they (and the radiated beam) move mostly at very slow sidereal rate, essentially identical in magnitude and at the opposite direction of Earth rotation.The DSN is in the process of revamping its documentation to provide analysis of the High Intensity Radiation Fields (HIRF) environment resulting from radio frequency radiation from DSN antennas for comparison to FAA regulations regarding certification of HIRF protection as outlined in the FAA regulations on HIRF protection for aircraft electrical and electronic systems (Title 14, Code of Federal Regulations (14 CFR) [section sign][section sign] 23.1308, 25.1317, 27.1317, and 29.1317).This paper presents work done at JPL, in consultation with the FAA. The work includes analysis of the radiated field structure created by the unique DSN emitters (combination of transmitters and antennas) and comparing it to the fields defined in the environments in the FAA regulations. The paper identifies areas that required special attention, including the implications of the very narrow beam of the DSN emitters and the sidereal rate motion. The paper derives the maximum emitter power allowed without mitigation and the mitigation zones, where required.Finally, the paper presents summary of the results of the analyses of the DSN emitters and the resulting DSN process documentation.

  13. Combustion properties of micronized coal for high intensity combustion applications

    SciTech Connect

    Freihaut, J.D.; Proscia, W.; Knight, B.; Vranos, A.; Hollick, H.; Wicks, K.

    1989-04-19

    Results are presented of an investigation of combustion related properties of micronized coal feeds (all particles less than 40 microns), mixing characteristics of centrifugally driven burner devices, and aerodynamic characteristics of micronized coal particles related to centrifugal mixing for high intensity combustion applications. Combustion related properties investigated are the evolution of fuel bound nitrogen and coal associated mineral matter during the initial stages of combustion. Parent and beneficiated micronized coal samples, as well as narrow size cut samples from a wide range of coal ranks, were investigated using a multireactor approach. The multireactor approach allowed the experimental separation of different aspects of the fuel nitrogen evolution process, enabling a comprehensive understanding of FBN to be formulated and empirical rate constants to be developed. A specially designed on-line gas analysis system allowed nitrogen balance to be achieved. A combined nitrogen and ash tracer technique allowed the quantitative determination of tar yields during rapid devolatilization. Empirical kinetic rates are developed for the evolution of FBN with tar at low temperatures and the appearance of HCN from tar and char species at high temperatures. A specially designed phase separation system, coupled to separate aerosol and char segregation trains, allowed the possible formation of ash aerosol by rapid devolatilization to be monitored. Compensated thermocouple, hot wire anemometry, and digital imaging techniques are employed to characterize the mixing properties of a centrifugally driven combustor. Analytical and experimental investigations of the fidelity of micronized coal particles to gas stream trajectories in the strong centrifugal fields are performed. Both spherical and nonspherical particle morphologies are considered analytically. 14 refs., 141 figs., 34 tabs.

  14. Glass Strengthening via High-Intensity Plasma-Arc Heating

    SciTech Connect

    Wereszczak, Andrew A; Harper, David C; Duty, Chad E; Patel, P

    2010-01-01

    The use of a high-intensity plasma-arc lamp was used to irradiate the surface of soda-lime silicate glass tiles to determine if an increase in strength could be achieved. The lamp had a power density of 3500 W/cm2, a processing area of 1 cm x 10 cm, irradiated near-infrared heating at a wavelength between 0.2 1.4 m, and was controlled to unidirectionally sweep across 50-mm-square tiles at a constant speed of 8 mm/s. Ring-on-ring (RoR) equibiaxial flexure and 4 pt uni-directional flexure testings of entire tiles were used to measure and compare failure stress distributions of treated and untreated glass. Even with non-optimized processing conditions, RoR failure stress increased by approximately 25% and the 4 pt bend failure stress increased by approximately 65%. Strengthening was due to a fire-polishing-like mechanism. The arc-lamp heat-treatment caused the location of the strength-limiting flaws in the 4-pt-bend tiles to change; namely, failure initiation occurred on the gage section surface for the treated glass whereas it occurred at a gage section edge for the untreated. Arc-lamp heat-treatment is attractive not only because it provides strengthening, but because it can (non-contact) process large amounts of glass quickly and inexpensively, and is a process that either a glass manufacturer or end-user can readily employ.

  15. High-Intensity Interval Exercise and Postprandial Triacylglycerol.

    PubMed

    Burns, Stephen F; Miyashita, Masashi; Stensel, David J

    2015-07-01

    This review examined if high-intensity interval exercise (HIIE) reduces postprandial triacylglycerol (TAG) levels. Fifteen studies were identified, in which the effect of interval exercise conducted at an intensity of >65% of maximal oxygen uptake was evaluated on postprandial TAG levels. Analysis was divided between studies that included supramaximal exercise and those that included submaximal interval exercise. Ten studies examined the effect of a single session of low-volume HIIE including supramaximal sprints on postprandial TAG. Seven of these studies noted reductions in the postprandial total TAG area under the curve the morning after exercise of between ~10 and 21% compared with rest, but three investigations found no significant difference in TAG levels. Variations in the HIIE protocol used, inter-individual variation or insufficient time post-exercise for an increase in lipoprotein lipase activity are proposed reasons for the divergent results among studies. Five studies examined the effect of high-volume submaximal interval exercise on postprandial TAG. Four of these studies were characterised by high exercise energy expenditure and effectively attenuated total postprandial TAG levels by ~15-30%, but one study with a lower energy expenditure found no effect on TAG. The evidence suggests that supramaximal HIIE can induce large reductions in postprandial TAG levels but findings are inconsistent. Submaximal interval exercise offers no TAG metabolic or time advantage over continuous aerobic exercise but could be appealing in nature to some individuals. Future research should examine if submaximal interval exercise can reduce TAG levels in line with more realistic and achievable exercise durations of 30 min per day.

  16. Development of a High Intensity Focused Ultrasound (HIFU) Hydrophone System

    NASA Astrophysics Data System (ADS)

    Schafer, Mark E.; Gessert, James

    2009-04-01

    The growing clinical use of High Intensity Focused Ultrasound (HIFU) has driven a need for reliable, reproducible measurements of HIFU acoustic fields. We have previously presented data on a reflective scatterer approach, incorporating several novel features for improved bandwidth, reliability, and reproducibility [Proc. 2005 IEEE Ultrasonics Symposium, 1739-1742]. We now report on several design improvements which have increase the signal to noise ratio of the system, and potentially reduced the cost of implementation. For the scattering element, we now use an artificial sapphire material to provide a more uniform radiating surface. The receiver is a segmented, truncated spherical structure with a 10 cm radius; the scattering element is positioned at the center of the sphere. The receiver is made from 25 micron thick, biaxially stretched PVDF, with a Pt-Au electrode on the front surface. In the new design, a specialized backing material provides the stiffness required to maintain structural stability, while at the same time providing both electrical shielding and ultrasonic absorption. Compared with the previous version, the new receiver design has improved the noise performance by 8-12 dB; the new scattering sphere has reduced the scattering loss by another 14 dB, producing an effective sensitivity of -298 dB re 1 microVolt/Pa. The design trade-off still involves receiver sensitivity with effective spot size, and signal distortion from the scatter structure. However, the reduced cost and improved repeatability of the new scatter approach makes the overall design more robust for routine waveform measurements of HIFU systems.

  17. Tools and techniques for estimating high intensity RF effects

    SciTech Connect

    Zacharias, R.; Pennock, S.; Poggio, A.; Ray, S.

    1991-07-01

    With the ever-increasing dependence of modern aircraft on sophisticated avionics and electronic controls, the need to assure aircraft survivatality when exposed to high Intensity RF (HIRF) signals has become of great Interest. Advisory regulation is currently being proposed which would require testing and/or analysis to assure RF hardness of installed flight critical and flight essential equipment. While full-aircraft, full-threat testing may be the most thorough manner to assure survivability, it is not generally practical in loins of cost. Various combinations of limited full-aircraft testing, box-level testing, modeling, and analysis are also being considered as methods to achieve compliance. Modeling, analysis, and low power measurements may hold the key to making full-system survivability estimates at reasonable cost. In this paper we will describe some of the tools and techniques we use for estimating and measuring coupling and component disturbance. A finite difference time domain modeling code, TSAR, used to predict coupling will be described. This code has the capability to quickly generate a mesh model to represent the test object. Some recent applications as well as the advantages and limitations of using such a code will be described. We will also describe some of the facilities and techniques we have developed for making low power coupling measurements and for making direct injection test measurements of device disturbance. Some scaling laws for coupling and device effects will be presented. A method to extrapolate these low-power test results to high-power full-system effects will be presented.

  18. Outcomes of exertional rhabdomyolysis following high-intensity resistance training.

    PubMed

    Huynh, A; Leong, K; Jones, N; Crump, N; Russell, D; Anderson, M; Steinfort, D; Johnson, D F

    2016-05-01

    High-intensity resistance training (HIRT) programmes are increasingly popular amongst personal trainers and those attending gymnasiums. We report the experience of exertional rhabdomyolysis (ER) at two tertiary hospitals in Melbourne, Australia. To compare the clinical outcomes of ER with other causes of rhabdomyolysis. Retrospective cross-sectional study of patients presenting with a serum creatine kinase (CK) of greater than 25 000 units/L from 1 September 2013 to 31 August 2014 at two tertiary referral hospitals in Melbourne, Australia. Records were examined to identify care measures implemented during hospital stay, clinical outcomes during admission and on subsequent follow up. Thirty four cases of rhabdomyolysis with a CK of greater than 25 000 units/L (normal range: 20-180 units/L) were identified during the 12-month study period. Twelve of the 34 cases (35%) had ER with 10 of 12 related to HIRT. No acute kidney injury, intensive care admission or death were seen among those with ER. All cases were managed conservatively, with 11 admitted and 9 receiving intravenous fluids only. In contrast, patients with rhabdomyolysis from other causes experienced significantly higher rates of intensive care admission (64%, P = 0.0002), acute kidney injury (82%, P = 0.0001) and death (27%, P = 0.069). ER resulting from HIRT appears to have a benign course compared with rhabdomyolysis of other aetiologies in patients with a serum CK greater than 25 000 units/L. Conservative management of ER appears to be adequate, although this requires confirmation in future prospective studies. © 2016 Royal Australasian College of Physicians.

  19. Design Aspects of Focal Beams From High-Intensity Arrays

    PubMed Central

    Stephens, Douglas N.; Kruse, Dustin E.; Qin, Shengping; Ferrara, Katherine W.

    2011-01-01

    As the applications of ultrasonic thermal therapies expand, the design of the high-intensity array must address both the energy delivery of the main beam and the character and relevance of off-target beam energy. We simulate the acoustic field performance of a selected set of circular arrays organized by array format, including flat versus curved arrays, periodic versus random arrays, and center void diameter variations. Performance metrics are based on the −3-dB focal main lobe (FML) positioning range, axial grating lobe (AGL) temperatures, and side lobe levels. Using finite-element analysis, we evaluate the relative heating of the FML and the AGLs. All arrays have a maximum diameter of 100λ, with element count ranging from 64 to 1024 and continuous wave frequency of 1.5 MHz. First, we show that a 50% spherical annulus produces focus beam side lobes which decay as a function of lateral distance at nearly 87% of the exponential rate of a full aperture. Second, for the arrays studied, the efficiency of power delivery over the −3-dB focus positioning range for spherical arrays is at least 2-fold greater than for flat arrays; the 256-element case shows a 5-fold advantage for the spherical array. Third, AGL heating can be significant as the focal target is moved to its distal half-intensity depth from the natural focus. Increasing the element count of a randomized array to 256 elements decreases the AGL-to-FML heating ratio to 0.12 at the distal half-intensity depth. Further increases in element count yield modest improvements. A 49% improvement in the AGL-to-peak heating ratio is predicted by using the Sumanaweera spiral element pattern with randomization. PMID:21859578

  20. Compliance with High-Intensity Radiated Fields Regulations - Emitter's Perspective

    NASA Technical Reports Server (NTRS)

    Statman, Joseph; Jamnejad, Vahraz; Nguyen, Lee

    2012-01-01

    NASA's Deep Space Network (DSN) uses high-power transmitters on its large antennas to communicate with spacecraft of NASA and its partner agencies. The prime reflectors of the DSN antennas are parabolic, at 34m and 70m in diameter. The DSN transmitters radiate Continuous Wave (CW) signals at 20 kW - 500 kW at X-band and S-band frequencies. The combination of antenna reflector size and high frequency results in a very narrow beam with extensive oscillating near-field pattern. Another unique feature of the DSN antennas is that they (and the radiated beam) move mostly at very slow sidereal rate, essentially identical in magnitude and at the opposite direction of Earth rotation.The DSN is in the process of revamping its documentation to provide analysis of the High Intensity Radiation Fields (HIRF) environment resulting from radio frequency radiation from DSN antennas for comparison to FAA regulations regarding certification of HIRF protection as outlined in the FAA regulations on HIRF protection for aircraft electrical and electronic systems (Title 14, Code of Federal Regulations (14 CFR) [section sign][section sign] 23.1308, 25.1317, 27.1317, and 29.1317).This paper presents work done at JPL, in consultation with the FAA. The work includes analysis of the radiated field structure created by the unique DSN emitters (combination of transmitters and antennas) and comparing it to the fields defined in the environments in the FAA regulations. The paper identifies areas that required special attention, including the implications of the very narrow beam of the DSN emitters and the sidereal rate motion. The paper derives the maximum emitter power allowed without mitigation and the mitigation zones, where required.Finally, the paper presents summary of the results of the analyses of the DSN emitters and the resulting DSN process documentation.

  1. NASA's New High Intensity Solar Environment Test Capability

    NASA Technical Reports Server (NTRS)

    Schneider, Todd A.; Vaughn, Jason A.; Wright, Kenneth H.

    2012-01-01

    Across the world, new spaceflight missions are being designed and executed that will place spacecraft and instruments into challenging environments throughout the solar system. To aid in the successful completion of these new missions, NASA has developed a new flexible space environment test platform. The High Intensity Solar Environment Test (HISET) capability located at NASA fs Marshall Space Flight Center provides scientists and engineers with the means to test spacecraft materials and systems in a wide range of solar wind and solar photon environments. Featuring a solar simulator capable of delivering approximately 1 MW/m2 of broad spectrum radiation at maximum power, HISET provides a means to test systems or components that could explore the solar corona. The solar simulator consists of three high-power Xenon arc lamps that can be operated independently over a range of power to meet test requirements; i.e., the lamp power can be greatly reduced to simulate the solar intensity at several AU. Integral to the HISET capability are charged particle sources that can provide a solar wind (electron and proton) environment. Used individually or in combination, the charged particle sources can provide fluxes ranging from a few nA/cm2 to 100s of nA/cm2 over an energy range of 50 eV to 100 keV for electrons and 100 eV to 30 keV for protons. Anchored by a high vacuum facility equipped with a liquid nitrogen cold shroud for radiative cooling scenarios, HISET is able to accommodate samples as large as 1 meter in diameter. In this poster, details of the HISET capability will be presented, including the wide ]ranging configurability of the system.

  2. Exercise training modalities in chronic heart failure: does high intensity aerobic interval training make the difference?

    PubMed

    Giallauria, Francesco; Smart, Neil Andrew; Cittadini, Antonio; Vigorito, Carlo

    2016-10-14

    Exercise training (ET) is strongly recommended in patients with chronic heart failure (CHF). Moderate-intensity aerobic continuous ET is the best established training modality in CHF patients. In the last decade, however, high-intensity interval exercise training (HIIT) has aroused considerable interest in cardiac rehabilitation community. Basically, HIIT consists of repeated bouts of high-intensity exercise alternated with recovery periods. In CHF patients, HIIT exerts larger improvements in exercise capacity compared to moderate-continuous ET. These results are intriguing, mostly considering that better functional capacity translates into an improvement of symptoms and quality of life. Notably, HIIT did not reveal major safety issues; although CHF patients should be clinically stable, have had recent exposure to at least regular moderate-intensity exercise, and appropriate supervision and monitoring during and after the exercise session are mandatory. The impact of HIIT on cardiac dimensions and function and on endothelial function remains uncertain. HIIT should not replace other training modalities in heart failure but should rather complement them. Combining and tailoring different ET modalities according to each patient's baseline clinical characteristics (i.e. exercise capacity, personal needs, preferences and goals) seem the most astute approach to exercise prescription.

  3. High-intensity interval exercise training for public health: a big HIT or shall we HIT it on the head?

    PubMed

    Biddle, Stuart J H; Batterham, Alan M

    2015-07-18

    The efficacy of high-intensity interval training for a broad spectrum of cardio-metabolic health outcomes is not in question. Rather, the effectiveness of this form of exercise is at stake. In this paper we debate the issues concerning the likely success or failure of high-intensity interval training interventions for population-level health promotion. Biddle maintains that high-intensity interval training cannot be a viable public health strategy as it will not be adopted or maintained by many people. This conclusion is based on an analysis of perceptions of competence, the psychologically aversive nature of high-intensity exercise, the affective component of attitudes, the less conscious elements of motivated behaviour that reflect our likes and dislikes, and analysis using the RE-AIM framework. Batterham argues that this appraisal is based on a constrained and outmoded definition of high-intensity interval training and that truly practical and scalable protocols have been - and continue to be - developed. He contends that the purported displeasure associated with this type of exercise has been overstated. Biddle suggests that the way forward is to help the least active become more active rather than the already active to do more. Batterham claims that traditional physical activity promotion has been a spectacular failure. He proposes that, within an evolutionary health promotion framework, high-intensity interval training could be a successful population strategy for producing rapid physiological adaptations benefiting public health, independent of changes in total physical activity energy expenditure. Biddle recommends that we focus our attention elsewhere if we want population-level gains in physical activity impacting public health. His conclusion is based on his belief that high-intensity interval training interventions will have limited reach, effectiveness, and adoption, and poor implementation and maintenance. In contrast, Batterham maintains that there

  4. SRM attrition rate study of the aft motor case segments due to water impact cavity collapse loading

    NASA Technical Reports Server (NTRS)

    Crockett, C. D.

    1976-01-01

    The attrition assessment of the aft segments of Solid Rocket Motor due to water impact requires the establishment of a correlation between loading occurrences and structural capability. Each discrete load case, as identified by the water impact velocities and angle, varies longitudinally and radially in magnitude and distribution of the external pressure. The distributions are further required to be shifted forward or aft one-fourth the vehicle diameter to assure minimization of the effect of test instrumentation location for the load determinations. The asymmetrical load distributions result in large geometric nonlinearities in structural response. The critical structural response is progressive buckling of the case. Discrete stiffeners have been added to these aft segments to aid in gaining maximum structural capability for minimum weight addition for resisting these loads. This report presents the development of the attrition assessment of the aft segments and includes the rationale for eliminating all assessable conservatisms from this assessment.

  5. Effect of a rapid repair mechanism for nitrification capacity in the load impact wastewater treatment

    NASA Astrophysics Data System (ADS)

    Hong, Wei; Zhang, Bing; Sun, Changdong; Tan, Xin; Liu, Bo; Zou, Xiaofeng

    2017-05-01

    The nitrification capacity in the wastewater treatment is very important, and is particularly vulnerable to impacts. In this study, a rapid repair mechanism for nitrification was built and the result showing that, with the addition of exogenous nitrifying bacteria and organic nutrient, the nitrification capacity in the pilot scale equipment was restored in 20h, the concentration of NH3-N in discharge conforms to the one-class A permitted criterion (GB 18918-2002) and remain stable for long time, while the nitrification capacity in control group would not be fixed by itself in 196h. The repaired experimental group has the advantage of strong shock resistance and stable operation, and under the second high impact load, the concentration of NH3-N in effluent remain stable.

  6. Impact of gravity loading on post-stroke reaching and its relationship to weakness.

    PubMed

    Beer, Randall F; Ellis, Michael D; Holubar, Bradley G; Dewald, Julius P A

    2007-08-01

    The ability to extend the elbow following stroke depends on the magnitude and direction of torques acting at the shoulder. The mechanisms underlying this link remain unclear. The purpose of this study was to evaluate whether the effects of shoulder loading on elbow function were related to weakness or its distribution in the paretic limb. Ten subjects with longstanding hemiparesis performed movements with the arm either passively supported against gravity by an air bearing, or by activation of shoulder muscles. Isometric maximum voluntary torques at the elbow and shoulder were measured using a load cell. The speed and range of elbow extension movements were negatively impacted by actively supporting the paretic limb against gravity. However, the effects of gravity loading were not related to proximal weakness or abnormalities in the elbow flexor-extensor strength balance. The findings support the existence of abnormal descending motor commands that constrain the ability of stroke survivors to generate elbow extension torque in combination with abduction torque at the shoulder.

  7. IMPACT OF GRAVITY LOADING ON POST-STROKE REACHING AND ITS RELATIONSHIP TO WEAKNESS

    PubMed Central

    Beer, Randall F.; Ellis, Michael D.; Holubar, Bradley G.; Dewald, Julius P.A.

    2010-01-01

    The ability to extend the elbow following stroke depends on the magnitude and direction of torques acting at the shoulder. The mechanisms underlying this link remain unclear. The purpose of this study was to evaluate whether the effects of shoulder loading on elbow function were related to weakness or its distribution in the paretic limb. Ten subjects with longstanding hemiparesis performed movements with the arm either passively supported against gravity by an air bearing, or by activation of shoulder muscles. Isometric maximum voluntary torques at the elbow and shoulder were measured using a load cell. The speed and range of elbow extension movements were negatively impacted by actively supporting the paretic limb against gravity. However, the effects of gravity loading were not related to proximal weakness or abnormalities in the elbow flexor–extensor strength balance. The findings support the existence of abnormal descending motor commands that constrain the ability of stroke survivors to generate elbow extension torque in combination with abduction torque at the shoulder. PMID:17486581

  8. Estimates of Minor Ocean Tide Loading Displacement and Its Impact on Continuous GPS Coordinate Time Series

    PubMed Central

    Li, Zhao; Jiang, Weiping; Ding, Wenwu; Deng, Liansheng; Peng, Lifeng

    2014-01-01

    The site displacement due to ocean tidal loading is regarded as one of the largest uncertainties in precise geodetic positioning measurements, among which the effect of minor ocean tides (MOT), except for the 11 main tidal constituents, are sometimes neglected in routine precise global positioning system (GPS) data processing. We find that MOT can cause large vertical loading displacements with peak-to-peak variations reaching more than 8 mm at coastal/island stations. The impact of MOT on the 24-hour GPS solution is slightly larger than the magnitude of MOT loading itself, with peak-to-peak displacement variation at about 10 mm for the horizontal and 30 mm for the vertical components. We also find that the vertical velocity of all the selected stations in the Southwest Pacific was reduced by more than 10% after considering the MOT effect, while stations with weighted root mean square reduced data account for 62%, 59%, and 36% for the up, east, and north components respectively, in particular for most coastal/island stations. Furthermore, MOT correction could significantly reduce the annual signal of the global stacked east component, the near fortnightly and the long-term periodic signals in the up component. The power of some anomalous harmonics of 1.04 cycle per year is also decreased to some extent. These results further proved the benefits of MOT correction in precise GPS data processing. PMID:24658620

  9. Estimates of minor ocean tide loading displacement and its impact on continuous GPS coordinate time series.

    PubMed

    Li, Zhao; Jiang, Weiping; Ding, Wenwu; Deng, Liansheng; Peng, Lifeng

    2014-03-20

    The site displacement due to ocean tidal loading is regarded as one of the largest uncertainties in precise geodetic positioning measurements, among which the effect of minor ocean tides (MOT), except for the 11 main tidal constituents, are sometimes neglected in routine precise global positioning system (GPS) data processing. We find that MOT can cause large vertical loading displacements with peak-to-peak variations reaching more than 8 mm at coastal/island stations. The impact of MOT on the 24-hour GPS solution is slightly larger than the magnitude of MOT loading itself, with peak-to-peak displacement variation at about 10 mm for the horizontal and 30 mm for the vertical components. We also find that the vertical velocity of all the selected stations in the Southwest Pacific was reduced by more than 10% after considering the MOT effect, while stations with weighted root mean square reduced data account for 62%, 59%, and 36% for the up, east, and north components respectively, in particular for most coastal/island stations. Furthermore, MOT correction could significantly reduce the annual signal of the global stacked east component, the near fortnightly and the long-term periodic signals in the up component. The power of some anomalous harmonics of 1.04 cycle per year is also decreased to some extent. These results further proved the benefits of MOT correction in precise GPS data processing.

  10. Understanding negative impacts of perceived cognitive load on job learning effectiveness: a social capital solution.

    PubMed

    Lin, Chieh-Peng

    2010-12-01

    This study proposes a model explaining how social capital helps ease excessively required mental effort. Although organizational researchers have studied both social capital and cognitive load, no prior research has critically examined the role of social capital in improving individuals' mental load and effort and consequently enhancing job learning effectiveness. This study surveys participants made up of professionals in Taiwan's information technology industry. It measures the constructs with the use of 5-point Likert-type scale items modified from existing literature. The survey data were analyzed with the use of structural equation modeling. Job learning effectiveness is negatively influenced by role ambiguity and role conflict. Time pressure has a positive influence on role ambiguity and role conflict Although the relationship between task complexity and role ambiguity is insignificant, task complexity has a positive influence on role conflict. Because the relationship between network ties and role conflict is insignificant, trust has a negative influence on role conflict. Last, shared vision has a negative influence on role ambiguity. This study provides an example of how social capital can be applied as a useful remedy to ease the negative impact of perceived cognitive load on job learning effectiveness. The negative relationship between shared vision and role ambiguity suggests that a shared vision helps in disseminating organizationally common goals and directions among employees to alleviate individuals' mental efforts in dealing with the ambiguity of their job roles. A firm's management team should take actions to decrease role conflict by strengthening trust among employees.

  11. Effects of high intensity exhaustive exercise on SOD, MDA, and NO levels in rats with knee osteoarthritis.

    PubMed

    Li, X D; Sun, G F; Zhu, W B; Wang, Y H

    2015-10-16

    The aim of this study was to investigate the impact of high intensity exhaustive exercise on nitric oxide (NO), malondialdehyde (MDA), and superoxide dismutase (SOD) expression in rats with knee osteoarthritis. Sprague Dawley rats were randomly divided into control (N = 5) and model (N = 35) groups; the model group was further divided into quiet (N = 5), low- (N = 15) and high- (N = 15) intensity exhaustive exercise groups. The low- and high-intensity groups were randomly divided into pre-exercise (N = 5), immediate post-exercise (N = 5), and 24-h post-exercise (N = 5) groups according to different time points for detection. NO, MDA, and SOD levels were compared between each group. The SOD levels in the quiet, low-, and high-intensity exhaustive exercise groups were lower than that in the control group, whereas the NO and MDA levels were higher in the former groups than in the controls (P < 0.05). The SOD level in the 24-h post-low intensity exhaustive exercise group was higher than that in the 24-h post-high intensity exhaustive exercise group, whereas the NO and MDA levels were lower in the 24-h post-low intensity than in the post-high intensity exercise group (P < 0.05). Overall, the results demonstrated that with the increase of exercise intensity, the SOD activity in the rats with knee osteoarthritis decreased gradually, whereas the MDA and NO levels gradually increased. Thus, the greater the exercise intensity, the more serious the impact on knee osteoarthritis.

  12. Modeling the impact of plant response to nitrogen loading on N retention in riparian wetlands

    NASA Astrophysics Data System (ADS)

    Dorheim, K.; Schade, J. D.; McKelvey, S.; Mazzag, B.

    2016-12-01

    To prevent the adverse effects of nitrogen loading from agricultural runoff on inland water ecosystems; land and water managers use riparian buffer strips as filters to reduce the nitrogen concentrations in runoff. Buffer strips function to reduce nitrogen (N) pollution via dissimilatory nitrate reduction and nutrient assimilation in plant biomass. While buffer strips appear to be a viable solution to nutrient pollution; much remains unknown about the effectiveness of buffer strips and the implications of plant physiology on long term N retention. To address how plant physiology affects N retention in buffer strips, we developed a simulation model that represents plant N uptake and N use by denitrifying microbes in a patch of a wetland ecosystem. The simulation model incorporates the dynamics of plant responses to changes in N availability. Previous empirical studies indicate an inverse relationship between N load and plant root-to-shoot ratio (R:S). In order to carry out denitrification, denitrifying microbes require nitrate and a reduced carbon compound; changes in N availability and soil organic matter can impact denitrification. Since soil organic matter is related to root detritus, changes in R:S can also impact denitrification. If R:S remains constant then we expect denitrification to increase with N availability, however if R:S changes in response to N availability then denitrification may decrease with increasing N availability. Using our model we were able to investigate the impact of plant responses to N availability on N retention. At high N concentrations with a constant R:S, denitrification accounted for 72% of the daily N retention. In contrast, when R:S is sensitive to changes in N availability denitrification accounts for only 30% of N retention. Total N retention varied with N load, at lower N concentrations the sensitive R:S simulation had lower N retention, where as the reverse was observed at higher N concentrations. These results suggest that

  13. Delamination growth analysis in quasi-isotropic laminates under loads simulating low-velocity impact

    NASA Technical Reports Server (NTRS)

    Shivakumar, K. N.; Elber, W.

    1984-01-01

    A geometrically nonlinear finite-element analysis was developed to calculate the strain energy released by delamination plates during impact loading. Only the first mode of deformation, which is equivalent to static deflection, was treated. Both the impact loading and delamination in the plate were assumed to be axisymmetric. The strain energy release rate in peeling, G sub I, and shear sliding, G sub II, modes were calculated using the fracture mechanics crack closure technique. Energy release rates for various delamination sizes and locations and for various plate configurations and materials were compared. The analysis indicated that shear sliding (G sub II) was the primary mode of delamination growth. The analysis also indicated that the midplane (maximum transverse shear stress plane) delamination was more critical and would grow before any other delamination of the same size near the midplane region. The delamination growth rate was higher (neutrally stable) for a low toughness (brittle) matrix and slower (stable) for high toughness matrix. The energy release rate in the peeling mode, G sub I, for a near-surface delamination can be as high as 0.5G sub II and can contribute significantly to the delamination growth.

  14. Impacts of the climate change on runoff and diffuse phosphorus load to Lake Balaton (Hungary).

    PubMed

    Kovács, A; Clement, A

    2009-01-01

    The paper outlines a multi-component assessment of the impacts of the climate change on runoff and total phosphorus loads to the large shallow Lake Balaton in Hungary. Present hydrological cycle of the lake catchment has been examined using the rainfall-runoff model WetSpa. Particular phosphorus concentration in runoff was estimated on the basis of the simulated streamflow using an empirical power equation. Dissolved phosphorus concentrations were determined as a function of landuse and soil type of the corresponding sub-catchment. The model was calibrated and validated against daily observations manually at monitoring sites of sixteen inflowing streams around the lake. Runoff stemming from shoreline urban developments was calculated by the urban runoff simulation model SWMM. Phosphorus concentrations in urban runoff were calculated by an empirical relationship derived from field measurements. The model was henceforward run for climate change scenario analysis. Present weather data were modified by the climate change scenarios imported from the results of the CLIME project. The results indicate that the impact of the climate change on runoff and phosphorus load appears in the change of the distribution within a time period rather than in the total volume. However, due to the high uncertainties in climate models, the presented calculations are possible assumptions rather than established statements.

  15. Delamination growth analysis in quasi-isotropic laminates under loads simulating low-velocity impact

    NASA Technical Reports Server (NTRS)

    Shivakumar, K. N.; Elber, W.

    1984-01-01

    A geometrically nonlinear finite-element analysis has been developed to calculate the strain energy released by delaminating plates during impact loading. Only the first mode of deformation, which is equivalent to static deflection, was treated. Both the impact loading and delamination in the plate were assumed to be axisymmetric. The strain energy release rate in peeling, GI, and shear sliding, GII, modes were calculated using the fracture mechanics crack closure technique. Energy release rates for various delamination sizes and locations and for various plate configurations and materials were compared. The analysis indicated that shear sliding was the primary mode of delamination growth. The analysis also indicated that the midplane (maximum transverse shear stress plane) delamination was more critical and would grow first before any other delamination of the same size near the midplane region. The delamination growth rate was higher (neutrally stable) for a low toughness (brittle) matrix and slower (stable) for high toughness matrix. The energy release rate in the peeling mode, GI, for a near-surface delamination can be as high as 0.5GII, and can contribute significantly to the delamination growth.

  16. Cognitive Load Differentially Impacts Response Control in Girls and Boys with ADHD

    PubMed Central

    Mostofsky, Stewart H.; Rosch, Keri S.

    2015-01-01

    Children with attention-deficit hyperactivity disorder (ADHD) consistently show impaired response control, including deficits in response inhibition and increased intrasubject variability (ISV) compared to typically-developing (TD) children. However, significantly less research has examined factors that may influence response control in individuals with ADHD, such as task or participant characteristics. The current study extends the literature by examining the impact of increasing cognitive demands on response control in a large sample of 81children with ADHD (40 girls) and 100 TD children (47 girls), ages 8–12 years. Participants completed a simple Go/No-Go (GNG) task with minimal cognitive demands, and a complex GNG task with increased cognitive load. Results showed that increasing cognitive load differentially impacted response control (commission error rate and tau, an ex-Gaussian measure of ISV) for girls, but not boys, with ADHD compared to same-sex TD children. Specifically, a sexually dimorphic pattern emerged such that boys with ADHD demonstrated higher commission error rate and tau on both the simple and complex GNG tasks as compared to TD boys, whereas girls with ADHD did not differ from TD girls on the simple GNG task, but showed higher commission error rate and tau on the complex GNG task. These findings suggest that task complexity influences response control in children with ADHD in a sexually dimorphic manner. The findings have substantive implications for the pathophysiology of ADHD in boys versus girls with ADHD. PMID:25624066

  17. Resistance Against the Intrinsic Rate of Fracture Mechanics Parameters for Polymeric Materials Under Moderate Impact Loading

    NASA Astrophysics Data System (ADS)

    Lach, R.; Seidler, S.; Grellmann, W.

    2005-09-01

    This study contributes towards understanding crack toughness as resistance against the intrinsic rate of fracture mechanics parameters. Up to now only few investigations have been done under moderate impact loading conditions. Based on experimental investigations using the crack resistance (R) concept, it has been shown that the stop block method combined with the multiple-specimen technique is a unique method for polymers under impact loading conditions in comparison with different R-curve methods. Other methods for the determination of R curve such as the low-blow technique are normally not applicable for polymers due to their time-dependent mechanical properties. The crack-tip opening displacement (CTOD) rate is a measurement of the rate sensibility of stable fracture process depending on the type of deformation, which can provide deep insights into the micromechanics and activation mechanisms during the fracture processes. In the polymeric materials mostly investigated, one can understand the stable crack propagation with three-stage processes; crack-tip blunting/crack initiation, non-stationary stable crack growth and steady-state stable crack growth (an equilibrium state). In this stable crack propagation, the values of normalized CTOD rate converge rapidly to a ‘matrix’-specific threshold. The stop block method in the multiple-specimen technique assures the criteria of the time-independent strain field around the crack tip and constant crack speed therewith and the J-integral is a valid toughness parameter.

  18. Analysis of Operation of Arch Frictional Joint Loaded with the Impact of Freely Falling Mass

    NASA Astrophysics Data System (ADS)

    Brodny, Jarosław

    2013-03-01

    Yielding support, commonly applied to secure dog headings, is made of carrying elements in the form of steel frames and friction props. Yielding capacity of this support is realized in frictional joints, which due to their geometry can be divided to straight and arch joints. Occurring in steel frames arch frictional joints are characterized with more complex loading state than straight joints used in friction props. In the article, there is presented an analysis of the state of stress and deformation of the arch frictional joint, which was carried out on the model of these joints using finite element method. The scope of the analysis included two methods of loading of arch frictional joint, namely its axial compression and bending. In both cases, joints were loaded dynamically with the impact of freely falling mass. Arch joints with and without passive pressure were submitted to an axial compression. Physical model of the frictional joint was developed on the basis of a system applied during the stand tests. To solve mathematical model an explicit integration method was used. As a result of analyses carried out, temporal courses of force transmitted through the frictional joint, and displacements of section sliding down were determined. On the basis of the temporal courses, dependences between maximum value of force transmitted through the frictional joint and the height from which the impact mass falls down were determined. Distributions of reduced stresses in elements of frictional joint were also determined and the state of deformation was described. In order to emphasize the difference between straight and arch frictional joints, also an analysis of internal forces in arch frictional joint depending on its geometrical parameters without and with passive pressure was presented.

  19. Early stage of crack extension in impact loaded high strength steels

    SciTech Connect

    Giovanola, J.H.

    1995-12-31

    Measuring accurate dynamic initiation fracture toughness values requires the understanding of the early stage of crack extension to interpret experimental records and determine the initiation point correctly. The early stage of dynamic crack extension in high strength steels was investigated by impacting fatigue-precracked specimens of R{sub C} 50 AISI 4340 and 300M steel in a range of sizes using the one-point-bend test method. By controlling load amplitude (by varying the impact velocity) and load duration (by varying the specimen geometry and dimensions), we were able to control dynamic crack extension to achieve complete fracture of the specimen, or crack arrest after a few tenths of millimeter to several millimeters of propagation. Crack speeds in these experiments did not exceed a few hundred meters per second. A two-dimensional analysis of the experimental results show that the resistance to dynamic crack extension in terms of the stress intensity factor K, increases substantially (30-50% above the value at initiation) during the first millimeters of propagation and that this increase is not directly dependent on crack velocity. Fractographic observations of arrested cracks reveal that even when only small shear lips developed during fracture, the crack front shape is significantly curved, with the front at the center of the specimen leading the front at the surfaces by several millimeters. The good correlation between the distance over which the propagation toughness increases and the depth of the curved crack front suggests that the rise in toughness is associated with the development of the curved Crack front. This study demonstrates that three-dimensional effects are important in dynamic fracture of even such model materials as macroscopically brittle high strength steels. These effects should be carefully considered when analyzing fracture under short duration impulsive loads or interpreting initiation data.

  20. Carbohydrate-electrolyte ingestion during intermittent high-intensity running.

    PubMed

    Nicholas, C W; Tsintzas, K; Boobis, L; Williams, C

    1999-09-01

    The purpose of this study was to examine the effects of ingesting a carbohydrate-electrolyte beverage or a noncarbohydrate placebo on muscle glycogen utilization during 90 min of intermittent high-intensity running. Six trained games players (age 24.6 +/- 2.2 yr; height 179.6 +/- 1.9 cm; body mass 74.5 +/- 2.0 kg; VO2max 56.3 +/- 1.3 mL x kg(-1) x min(-1); mean +/- SEM) performed two exercise trials, 7 d apart. The subjects were university soccer, hockey, or rugby players. On each occasion, they completed six 15-min periods of intermittent running, consisting of maximal sprinting, interspersed with less intense periods of running and walking. During each trial, subjects consumed either a 6.9% carbohydrate-electrolyte solution (CHO-E: the CHO trial) or a noncarbohydrate placebo (the CON trial) immediately before exercise (5 mL x kg(-1) BM) and after every 15 min of exercise thereafter (2 mL x kg(-1) BM). Drinks were administered in a double-blind, counter-balanced order, and the total volume of fluid consumed during each trial was 1114 +/- 30 mL. Needle biopsy samples were obtained from the vastus lateralis muscle before and after 90 min of exercise. Venous blood samples were collected from an antecubital vein at rest and every 30 min during exercise. Muscle glycogen utilization in mixed muscle samples was lower (P < 0.05) during CHO [192.5 +/- 26.3 mmol glucosyl units (kg x DM(-1))] than CON [245.3 +/- 22.9 mmol glucosyl units (kg x DM(-1))]. Single fiber analysis on the biopsy samples of the subjects during the CON trial showed a greater glycogen utilization in the Type II fibers compared with Type I fibers during this type of exercise [Type I: 182.2 +/- 34.5 vs Type II: 287.4 +/- 41.2 mmol glucosyl units (kg x DM(-1)); P < 0.05). After 30 min of exercise, blood lactate was significantly greater (P < 0.05) and serum insulin concentration lower (P < 0.05) in CON. In summary, when trained games players ingested a carbohydrate-electrolyte beverage, muscle glycogen

  1. Frequency conversion of high-intensity, femtosecond laser pulses

    SciTech Connect

    Banks, P S

    1997-06-01

    Almost since the invention of the laser, frequency conversion of optical pulses via non- linear processes has been an area of active interest. However, third harmonic generation using ~(~1 (THG) in solids is an area that has not received much attention because of ma- terial damage limits. Recently, the short, high-intensity pulses possible with chirped-pulse amplification (CPA) laser systems allow the use of intensities on the order of 1 TW/cm2 in thin solids without damage. As a light source to examine single-crystal THG in solids and other high field inter- actions, the design and construction of a Ti:sapphire-based CPA laser system capable of ultimately producing peak powers of 100 TW is presented. Of special interest is a novel, all-reflective pulse stretcher design which can stretch a pulse temporally by a factor of 20,000. The stretcher design can also compensate for the added material dispersion due to propagation through the amplifier chain and produce transform-limited 45 fs pulses upon compression. A series of laser-pumped amplifiers brings the peak power up to the terawatt level at 10 Hz, and the design calls for additional amplifiers to bring the power level to the 100 TW level for single shot operation. The theory for frequency conversion of these short pulses is presented, focusing on conversion to the third harmonic in single crystals of BBO, KD*P, and d-LAP (deuterated I-arginine phosphate). Conversion efficiencies of up to 6% are obtained with 500 fs pulses at 1053 nm in a 3 mm thick BBO crystal at 200 GW/cm 2. Contributions to this process by unphasematched, cascaded second harmonic generation and sum frequency generation are shown to be very significant. The angular relationship between the two orders is used to measure the tensor elements of C = xt3)/4 with Crs = -1.8 x 1O-23 m2/V2 and .15Cri + .54Crs = 4.0 x 1O-23 m2/V2. Conversion efficiency in d-LAP is about 20% that in BBO and conversion efficiency in KD*P is 1% that of BBO. It is calculated

  2. Development of a High Intensity Focused Ultrasound (HIFU) Hydrophone System

    NASA Astrophysics Data System (ADS)

    Schafer, Mark E.; Gessert, James; Moore, Wayne

    2006-05-01

    Concomitant with the growing clinical use of High Intensity Focused Ultrasound (HIFU), there has been a need for reliable, economical and reproducible measurements of HIFU acoustic fields. A number of approaches have been proposed and investigated, most notably by Kaczkowski et al [Proc. 2003 IEEE Ultrasonics Symposium, 982-985]. We are developing a similar reflective scatterer approach, incorporating several novel features which improve the hydrophone's bandwidth, reliability, and reproducibility. For the scattering element, we have used a fused silica optical fiber with a polyamide protective coating. The receiver is designed as a segmented, truncated spherical structure with a 10cm radius; the scattering element is positioned at the center of the sphere. The receiver is made from 25 micron thick, biaxially stretched PVDF, with a Pt-Au electrode on the front surface. Each segment has its own high impedance, wideband preamplifier, and the signals from multiple segments are summed coherently. As an additional feature, the system is designed to pulse the PVDF elements so that the pulse-echo response can be used to align the fiber at the center. Initial tests of the system have demonstrated a receiver array sensitivity of -279 dB re 1 microVolt/Pa (before preamplification), with a scattering loss at the fiber of approximately 39dB, producing an effective sensitivity of -318 dB re 1 micro Volt/Pa. The addition of the closely coupled wideband preamplifiers boosts the signal to a range which is sufficient for the measurement of HIFU transducers. The effective bandwidth of the system exceeds 15MHz, through careful design and the use of PVDF as a sensor material. In order to test the system, a HIFU transducer in the 4.0MHz frequency range was tested at low output settings using a conventional PVDF membrane hydrophone. The prototype system was then used to characterize the same HIFU transducer at full power. The results showed good correlation between waveforms and cross

  3. High-intensity re-warm-ups enhance soccer performance.

    PubMed

    Zois, J; Bishop, D; Fairweather, I; Ball, K; Aughey, R J

    2013-09-01

    The effects of high-intensity, short-duration, re-warm-ups on team-sport-related performance were investigated. In a randomised, cross-over study, participants performed 2×26-min periods of an intermittent activity protocol (IAP) on a non-motorized treadmill, interspersed by 15-min of passive recovery (CON); 3-min small-sided game (SSG); or a 5RM leg-press. Measures included counter-movement jump, repeated-sprint, the Loughborough soccer passing test (LSPT), blood lactate concentration, heart-rate, and perceptual measures. Data were analyzed using effect size (90% confidence intervals), and percentage change; determining magnitudes of effects. A 5RM re-warm-up improved flight-time to contraction-time ratio when compared to SSG (9.8%, ES; 0.5±0.3) and CON (ES: 9.4%, 0.7±0.5) re-warm-ups, remaining higher following the second IAP (8.8%, ES; 0.5±0.3 and 10.2%, ES; 0.6±0.6, respectively). Relative-maximum rate-of-force development was greater in the 5RM condition following the second IAP compared to SSG (29.3%, ES; 0.7±0.5) and CON (16.2%, ES; 0.6±0.6). Repeated-sprint ability during the second IAP improved in the 5RM re-warm-up; peak velocity, mean velocity, and acceleration were 4, 3, and 18% greater, respectively. Within groups, the SSG re-warm-up improved LSPT performance post-intervention; 6.4% (ES: 0.6±0.8) and following the second IAP 6.2% (ES: 0.6±0.6), compared to pre-intervention. A 5RM leg-press re-warm-up improved physical performance, while a SSG re-warm-up enhanced skill execution following standardized intermittent exercise. © Georg Thieme Verlag KG Stuttgart · New York.

  4. Co-ingestion of Nutritional Ergogenic Aids and High-Intensity Exercise Performance.

    PubMed

    Naderi, Alireza; Earnest, Conrad P; Lowery, Ryan P; Wilson, Jacob M; Willems, Mark E T

    2016-10-01

    Many sports involve repeated bouts of high-intensity exercise. High-intensity exercise is compromised, however, by the early onset of exercise-induced fatigue. Metabolic by-products, ion dysbalance and amount of phosphocreatine are considered the main peripheral causes of fatigue during high-intensity exercise. Intake of nutritional ergogenic aids is commonplace to enhance performance of high-intensity exercise by offsetting the potential mechanisms of fatigue. Creatine, probably one of the best known nutritional aids to enhance performance of high-intensity exercise, has convincingly substantiated its ergogenic potential. Although multi-ingredient supplements are now common, the justification for effectiveness is mostly based on observations with single intake of those ingredients. In this narrative review, the main focus is on the evidence of the effect of co-ingestion of ergogenic aids on performance of high intensity exercise for which the single intake has shown beneficial effects on high-intensity performance.

  5. An in vitro dynamic evaluation of prophylactic knee braces during lateral impact loading.

    PubMed

    Erickson, A R; Yasuda, K; Beynnon, B; Johnson, R; Pope, M

    1993-01-01

    To determine the ability of prophylactic knee braces to reduce or limit medial collateral and anterior cruciate ligament elongation under dynamic loading conditions, we used cadaveric specimens that had a surrogate soft tissue material that matched the tissue compliance of in vivo contracted muscles. Eight cadaveric specimens were fitted with four prophylactic knee braces and instrumented with Hall Effect Strain Transducers on both the medial collateral and anterior cruciate ligament. Each specimen was mounted in a testing frame while a lateral impact was applied to the knee joint by a pendulum at levels below the injury threshold. Legs were tested at 0 degrees and 30 degrees of knee flexion, both with and without an intact anterior cruciate ligament. The maximum elongation for each ligament was calculated as a percentage of the initial measured length. The addition of a prophylactic knee brace significantly reduced the level of impact force at the point of impact, but this did not result in a significant reduction of anterior cruciate ligament elongation for any test. Although not significant, all braces tested were more effective at reducing medial collateral ligament elongation during a lateral impact with the knee flexion at 30 degrees than at 0 degrees.

  6. Space charge measurements with a high intensity bunch at the Fermilab Main Injector

    SciTech Connect

    Seiya, K.; Chase, B.; Dey, J.; Joireman, P.; Kourbanis, I.; Yagodnitsyna, A.; /Novosibirsk State U.

    2011-03-01

    For Project X, the Fermilab Main Injector will be required to operate with 3 times higher bunch intensity. The plan to study the space charge effects at the injection energy with intense bunches will be discussed. A multi-MW proton facility has been established as a critical need for the U.S. HEP program by HEPAP and P5. Utilization of the Main Injector (MI) as a high intensity proton source capable of delivering in excess of 2 MW beam power will require a factor of three increase in bunch intensity compared to current operations. Instabilities associated with beam loading, space charge, and electron cloud effects are common issues for high intensity proton machines. The MI intensities for current operations and Project X are listed in Table 1. The MI provides proton beams for Fermilab's Tevatron Proton-Antiproton Collider and MINOS neutrino experiments. The proposed 2MW proton facility, Project X, utilizes both the Recycler (RR) and the MI. The RR will be reconfigured as a proton accumulator and injector to realize the factor 3 bunch intensity increase in the MI. Since the energy in the RR and the MI at injection will be 6-8 GeV, which is relatively low, space charge effects will be significant and need to be studied. Studies based on the formation of high intensity bunches in the MI will guide the design and fabrication of the RF cavities and space-charge mitigation devices required for 2 MW operation of the MI. It is possible to create the higher bunch intensities required in the MI using a coalescing technique that has been successfully developed at Fermilab. This paper will discuss a 5 bunch coalescing scheme at 8 GeV which will produce 2.5 x 10{sup 11} protons in one bunch. Bunch stretching will be added to the coalescing process. The required RF parameters were optimized with longitudinal simulations. The beam studies, that have a goal of 85% coalescing efficiency, were started in June 2010.

  7. Odd-impact loading results in increased cortical area and moments of inertia in collegiate athletes.

    PubMed

    Weidauer, Lee; Minett, Maggie; Negus, Charles; Binkley, Teresa; Vukovich, Matt; Wey, Howard; Specker, Bonny

    2014-01-01

    The purpose of this study was to investigate tibial changes in volumetric bone mineral density and geometry that take place in athletes from pre- to post-season. Female college athletes (n = 36) and ten controls recruited from the student population were included in the study. Participants had their left tibia scanned by pQCT at 4, 20, and 66 % of the overall length from the distal end before and after their competitive seasons. Subjects were divided into four groups: non-athlete (controls, n = 10), moderate-impact (cross-country runners, n = 13), high-impact (volleyball and basketball, n = 11), and odd-impact (soccer, n = 12). Anterior-posterior and medial-lateral diameter increased at the 4 % site in control subjects. In the moderate-impact group, medial-lateral moment of inertia (MOI) increased by 1.2 ± 1.8 (mean ± SD) percent at the 20 % site. In high-impact group, anterior-posterior MOI increased by 1.6 ± 2.0 percent at the 66 % site. In odd-impact group, cortical area (1.4 ± 2.3 %) and cortical thickness (1.8 ± 2.8 %) increased at the 20 % site increased, as did the polar MOI (1.8 ± 2.2 %) at the 66 % site. Load-specific changes resulting in improved measures of bone strength take place in athletes during a competitive season. These changes may result in improved resistance to fractures and stress fractures.

  8. The effect of high-intensity aerobic interval training on postinfarction left ventricular remodelling

    PubMed Central

    Godfrey, Richard; Theologou, Thomas; Dellegrottaglie, Santo; Binukrishnan, Sukumaran; Wright, Jay; Whyte, Gregory; Ellison, Georgina

    2013-01-01

    This is the third in a series of case studies on an individual with normal coronaries who sustained an idiopathic acute myocardial infarction . Bilateral pulmonary emboli almost 2 years post-myocardial infarction (MI) revealed coagulopathy as the cause. The original MI resulted in 16% myocardial scar tissue. An increasing number of patients are surviving MI, hence the burden for healthcare often shifts to heart failure. Accumulating evidence suggests high-intensity aerobic interval exercise (AHIT) is efficacious in improving cardiac function in health and disease. However, its impact on MI scar has never been assessed. Accordingly, the 50-year-old subject of this case study undertook 60 weeks of regular AHIT. Successive cardiac MRI results demonstrate, for the first time, a decrease in MI scar with exercise and, alongside mounting evidence of high efficacy and low risk, suggests AHIT may be increasingly important in future prevention and reversing of disease and or amelioration of symptoms. PMID:23413285

  9. High Intensity Beam and X-Ray Converter Target Interactions and Mitigation

    SciTech Connect

    Chem, Y-J; McCarrick, J F; Guethlein, G; Chambers, F; Falabella, S; Lauer, E; Richardson, R; Weir, J

    2002-07-31

    Ions extracted from a solid surface or plasma by impact of an high intensity and high current electron beam can partially neutralize the beam space charge and change the focusing system. We have investigated ion emission computationally and experimentally. By matching PIC simulation results with available experimental data, our finding suggests that if a mix of ion species is available at the emitting surface, protons dominate the backstreaming ion effects, and that, unless there is surface flashover, ion emission is source limited. We have also investigated mitigation, such as e-beam cleaning, laser cleaning and ion trapping with a foil barrier. The temporal behavior of beam spot size with a foil barrier and a focusing scheme to improve foil barrier performance are discussed.

  10. High Intensity Beam and X-Ray Converter Target Interactions and Mitigation

    NASA Astrophysics Data System (ADS)

    Chen, Yu-Jiuan; McCarrick, James F.; Guethlein, Gary; Caporaso, George J.; Chambers, Frank; Falabella, Steven; Lauer, Eugene; Richardson, Roger; Sampayan, Steve; Weir, John

    2002-12-01

    Ions extracted from a solid surface or plasma by impact of an high intensity and high current electron beam can partially neutralize the beam space charge and change the focusing system. We have investigated ion emission computationally and experimentally. By matching PIC simulation results with available experimental data, our finding suggests that if a mix of ion species is available at the emitting surface, protons dominate the backstreaming ion effects, and that, unless there is surface flashover, ion emission is source limited. We have also investigated mitigation, such as e-beam cleaning, laser cleaning and ion trapping with a foil barrier. The temporal behavior of beam spot size with a foil barrier and a focusing scheme to improve foil barrier performance are discussed.

  11. Final Report for "Modeling Electron Cloud Diagnostics for High-Intensity Proton Accelerators"

    SciTech Connect

    Seth A Veitzer

    2009-09-25

    Electron clouds in accelerators such as the ILC degrade beam quality and limit operating efficiency. The need to mitigate electron clouds has a direct impact on the design and operation of these accelerators, translating into increased cost and reduced performance. Diagnostic techniques for measuring electron clouds in accelerating cavities are needed to provide an assessment of electron cloud evolution and mitigation. Accurate numerical modeling of these diagnostics is needed to validate the experimental techniques. In this Phase I, we developed detailed numerical models of microwave propagation through electron clouds in accelerating cavities with geometries relevant to existing and future high-intensity proton accelerators such as Project X and the ILC. Our numerical techniques and simulation results from the Phase I showed that there was a high probability of success in measuring both the evolution of electron clouds and the effects of non-uniform electron density distributions in Phase II.

  12. Detailed studies of Minor Actinide transmutation-incineration in high-intensity neutron fluxes

    SciTech Connect

    Bringer, O.; Blandin, C.; Oriol, L.

    2006-07-01

    The Mini-INCA project is dedicated to the measurement of incineration-transmutation chains and potentials of minor actinides in high-intensity thermal neutron fluxes. In this context, new types of detectors and methods of analysis have been developed. The {sup 241}Am and {sup 232}Th transmutation-incineration chains have been studied and several capture and fission cross sections measured very precisely, showing some discrepancies with existing data or evaluated data. An impact study was made on different based-like GEN-IV reactors. It underlines the necessity to proceed to precise measurements for a large number of minor-actinides that contribute to these future incineration scenarios. (authors)

  13. Hollow Atom Production Due to High Intensity X-ray Sources Irradiating Clusters And Its Applications

    SciTech Connect

    Moribayashi, Kengo

    2009-07-25

    This paper shows the production of hollow atoms and the proposal of the measurement by using x-ray flux irradiating clusters by continuing work from our previous papers left braceK. Moribayashi, J.Phys.B, 41 085602 (2008)right brace. The x-ray emissions from hollow atoms produced by high intensity x-ray sources are employed for this measurement. This measurement is useful for the application of laser-driven x-ray sources and x-ray free electron lasers to the measurement of diffraction patterns of bio-molecules, which is indispensable for the study of their three-dimensional structure. This paper develops the methods and discussions of our previous paper. Namely, the electron impact ionization processes are added to our calculation model. Further, the size effects of the targets are shown.

  14. Fish Mercury Loads and Lake Productivity Are Not Impacted by Wildland Fire in Northern Minnesota

    NASA Astrophysics Data System (ADS)

    Riggs, C.; Kolka, R. K.; Nater, E. A.; Witt, E.; Wickman, T.; Woodruff, L. G.; Butcher, J.

    2016-12-01

    Wildland fire can significantly alter mercury (Hg) cycling on land and in adjacent aquatic environments. In addition to enhancing local atmospheric Hg deposition, fire can influence terrestrial movement of Hg and other elements into lakes via runoff from burned upland soil. However, the impact of fire on water quality and the accumulation of Hg in fish remains equivocal. We investigated the effects of fire - specifically a low severity prescribed fire and moderate severity wildfire - on young-of-the-year yellow perch (Perca flavescens) and lake chemistry in two small remote watersheds in the Boundary Waters Canoe Area Wilderness in northeastern Minnesota using a paired watershed approach (fire-impacted vs. control watershed). Prior to fire, surface soil in the two study watersheds contained significant loads of Hg, mainly from atmospheric deposition. We expected fire to increase transport and deposition of Hg from smoke and burned soil into the fire-impacted lake, leading to changes in lake productivity and fish Hg loads. In contrast to our prediction, and despite significant effects of the moderate severity wildfire fire on upland soil Hg stocks, fish Hg accumulation and lake productivity were not affected by fire. Instead, climate and lake water levels were the strongest predictors of lake chemistry and fish responses in our study lakes. Our results suggest that low to moderate severity wildland fire does not alter lake productivity nor Hg accumulation in young-of-the-year yellow perch in these small, shallow lakes in the northern deciduous and boreal forest region. The effect of a high severity fire remains to be tested.

  15. Carbohydrate mouth rinse improves morning high-intensity exercise performance.

    PubMed

    Clarke, Neil D; Hammond, Scott; Kornilios, Evangelos; Mundy, Peter D

    2017-09-01

    Oral carbohydrate (CHO) rinsing has been demonstrated to provide beneficial effects on exercise performance of durations of up to one hour. The aim of the present study was to investigate the effects of CHO mouth rinsing on morning high-intensity exercise performance. Following institutional ethical approval and familiarisation, 12 healthy males (mean ± SD age: 23 ± 3 years, height: 175.5 ± 7.4 cm, body mass: 75.4 ± 7.5 kg) participated in this study. Countermovement jump (CMJ) height, isometric mid-thigh pull peak force, 10 m sprint time and bench press and back squat repetitions to failure were assessed following CHO and placebo (PLA) rinsing or a control condition (CON). All testing took place at 07:30 following an 11 hour overnight fast. Performance of CMJ height (CHO: 39 ± 7 cm; PLA: 38 ± 7 cm; CON: 36 ± 6 cm; P = .003, [Formula: see text] = 0.40), 10 m sprint time (CHO: 1.78 ± 0.07 s; PLA: 1.81 ± 0.07 s; CON: 1.85 ± 0.05 s; P = .001, [Formula: see text] = 0.47), the number of bench press (CHO: 25 ± 3; PLA: 24 ± 4; CON: 22 ± 4; P < .001, [Formula: see text] = 0.55) and squat (CHO: 31 ± 4; PLA: 29 ± 5; CON: 26 ± 6; P < .001, [Formula: see text] = 0.70) repetitions and mean felt arousal (CHO: 5 ± 1; PLA: 4 ± 0; CON: 4 ± 0; P = .009, [Formula: see text] = 0.25) improved following CHO rinsing. However, isometric mid-thigh pull peak force was unchanged (CHO: 2262 ± 288 N; PLA: 2236 ± 354 N; CON: 2212 ± 321 N; P = .368, [Formula: see text] = 0.08). These results suggest that oral CHO rinsing solution significantly improved the morning performance of CMJ height, 10 m sprint times, bench press and squat repetitions to failure and felt arousal, although peak force during an isometric mid-thigh pull, rating of perceived exertion and heart rate were unaffected.

  16. The effect of playing formation on high-intensity running and technical profiles in English FA Premier League soccer matches.

    PubMed

    Bradley, Paul S; Carling, Chris; Archer, Dave; Roberts, Jenny; Dodds, Andrew; Di Mascio, Michele; Paul, Darren; Diaz, Antonio Gomez; Peart, Dan; Krustrup, Peter

    2011-05-01

    The aim of this study was to examine the effect of playing formation on high-intensity running and technical performance during elite soccer matches. Twenty English FA Premier League games were analysed using a multiple-camera computerized tracking system (n = 153 players). Overall ball possession did not differ (P < 0.05) between 4-4-2, 4-3-3 and 4-5-1 formations (50%, s = 7 vs. 49%, s = 8 vs. 44%, s = 6). No differences were observed in high-intensity running between 4-4-2, 4-3-3 and 4-5-1 formations. Compared with 4-4-2 and 4-3-3 formations, players in a 4-5-1 formation performed less very high-intensity running when their team was in possession (312 m, s = 196 vs. 433 m, s = 261 vs. 410 m, s = 270; P 5 0.05) but more when their team was not in possession (547 m, s = 217 vs. 461 m, s = 156 vs. 459 m, s = 169; P < 0.05). Attackers in a 4-3-3 performed ~30% more (P < 0.05) high-intensity running than attackers in 4-4-2 and 4-5-1 formations. However, the fraction of successful passes was highest in a 4-4-2 (P < 0.05) compared with 4-3-3 and 4-5-1 formations. The results suggest that playing formation does not influence the overall activity profiles of players, except for attackers, but impacts on very high-intensity running activity with and without ball possession and some technical elements of performance.

  17. Endothelial function does not improve with high-intensity continuous exercise training in SHR: implications of eNOS uncoupling.

    PubMed

    Battault, Sylvain; Singh, François; Gayrard, Sandrine; Zoll, Joffrey; Reboul, Cyril; Meyer, Grégory

    2016-02-01

    Exercise training is a well-recognized way to improve vascular endothelial function by increasing nitric oxide (NO) bioavailability. However, in hypertensive subjects, unlike low- and moderate-intensity exercise training, the beneficial effects of continuous high-intensity exercise on endothelial function are not clear, and the underlying mechanisms remain unknown. The aim of this study was to investigate the impact of high-intensity exercise on vascular function, especially on the NO pathway, in spontaneous hypertensive rats (SHR). These effects were studied on WKY, sedentary SHR and SHR that exercised at moderate (SHR-MOD) and high intensity (SHR-HI) on a treadmill (1 h per day; 5 days per week for 6 weeks at 55% and 80% of their maximal aerobic velocity, respectively). Endothelial function and specific NO contributions to acetylcholine-mediated relaxation were evaluated by measuring the aortic ring isometric forces. Endothelial nitric oxide synthase (eNOS) expression and phosphorylation (ser1177) were evaluated by western blotting. The total aortic and eNOS-dependent reactive oxygen species (ROS) production was assessed using electron paramagnetic resonance in aortic tissue. Although the aortas of SHR-HI had increased eNOS levels without alteration of eNOS phosphorylation, high-intensity exercise had no beneficial effect on endothelium-dependent vasorelaxation, unlike moderate exercise. This result was associated with increased eNOS-dependent ROS production in the aortas of SHR-HI. Notably, the use of the recoupling agent BH4 or a thiol-reducing agent blunted eNOS-dependent ROS production in the aortas of SHR-HI. In conclusion, the lack of a positive effect of high-intensity exercise on endothelial function in SHR was mainly explained by redox-dependent eNOS uncoupling, resulting in a switch from NO to O2(-) generation.

  18. Observation and Simulation of Motion and Deformation for Impact-Loaded Metal Cylinders

    NASA Astrophysics Data System (ADS)

    Hickman, R. J.; Wise, J. L.; Smith, J. A.; Mersch, J. P.; Robino, C. V.; Arguello, J. G.

    2015-06-01

    Complementary gas-gun experiments and computational simulations have examined the time-resolved motion and post-mortem deformation of cylindrical metal samples subjected to impact loading. The effect of propagation distance on a compressive waveform generated in a sample by planar impact at one end was determined using a velocity interferometer to track the longitudinal motion of the opposing rear (i.e., free) surface. Samples (24 or 25.4-mm diameter) were fabricated from aluminum (types 6061 and 7075), copper, stainless steel (type 316), and cobalt alloy L-605 (AMS 5759). For each material, waveforms obtained for a short (2 mm) and a long (25.4 mm) cylinder corresponded, respectively, to one-dimensional (i.e., uniaxial) and two-dimensional strain at the measurement point. The wave-profile data have been analyzed to (i) establish key dynamic material modeling parameters, (ii) assess the functionality of the Sierra Solid Mechanics-Presto (SierraSM/Presto) code, and (iii) identify the need for additional testing, material modeling, and/or code development. The results of subsequent simulations have been compared to benchmark recovery experiments that showed the residual plastic deformation incurred by cylinders following end, side, and corner impacts. Sandia National Laboratories is a multi-program laboratory managed and operated by Sandia Corporation, a wholly owned subsidiary of Lockheed Martin Corporation, for the U.S. Department of Energy's National Nuclear Security Administration under Contract DE-AC04-94AL85000.

  19. Observation and simulation of motion and deformation for impact-loaded metal cylinders

    NASA Astrophysics Data System (ADS)

    Hickman, R. J.; Wise, J. L.; Smith, J. A.; Mersch, J. P.; Robino, C. V.; Arguello, J. G.

    2017-01-01

    Complementary gas-gun experiments and computational simulations have examined the time-resolved motion and post-mortem deformation of cylindrical metal samples subjected to impact loading. The effect of propagation distance on a compressive waveform generated in a sample by planar impact at one end was determined using a velocity interferometer to track the longitudinal motion at the center of the opposing rear (i.e., free) surface. Samples (25.4-mm diameter) were fabricated from aluminum (types 6061 and 7075), copper (OFHC = oxygen free, high conductivity), stainless steel (type 316), and cobalt alloy L-605 (AMS 5759; also referenced as Haynes®25 alloy). For each material, waveforms obtained for a 25.4-mm long cylinder corresponded to two-dimensional strain at the measurement point. The wave-profile data have been analyzed to (i) establish key dynamic material modeling parameters, (ii) assess the functionality of the Sierra Solid Mechanics-Presto (Sierra/SM) code, and (iii) identify the need for additional testing, material modeling, and/or code development. The results of subsequent simulations have been compared to benchmark recovery experiments that showed the residual plastic deformation incurred by cylinders following end, side, and corner impacts.

  20. Application of microtomography and image analysis to the quantification of fragmentation in ceramics after impact loading

    NASA Astrophysics Data System (ADS)

    Forquin, Pascal; Ando, Edward

    2017-01-01

    Silicon carbide ceramics are widely used in personal body armour and protective solutions. However, during impact, an intense fragmentation develops in the ceramic tile due to high-strain-rate tensile loadings. In this work, microtomography equipment was used to analyse the fragmentation patterns of two silicon carbide grades subjected to edge-on impact (EOI) tests. The EOI experiments were conducted in two configurations. The so-called open configuration relies on the use of an ultra-high-speed camera to visualize the fragmentation process with an interframe time set to 1 µs. The so-called sarcophagus configuration consists in confining the target in a metallic casing to avoid any dispersion of fragments. The target is infiltrated after impact so the final damage pattern is entirely scanned using X-ray tomography and a microfocus source. Thereafter, a three-dimensional (3D) segmentation algorithm was tested and applied in order to separate fragments in 3D allowing a particle size distribution to be obtained. Significant differences between the two specimens of different SiC grades were noted. To explain such experimental results, numerical simulations were conducted considering the Denoual-Forquin-Hild anisotropic damage model. According to the calculations, the difference of crack pattern in EOI tests is related to the population of defects within the two ceramics. This article is part of the themed issue 'Experimental testing and modelling of brittle materials at high strain rates'.

  1. Glycemic impact, glycemic glucose equivalents, glycemic index, and glycemic load: definitions, distinctions, and implications.

    PubMed

    Monro, John A; Shaw, Mick

    2008-01-01

    Glycemic impact, defined as "the weight of glucose that would induce a glycemic response equivalent to that induced by a given amount of food" (American Association of Cereal Chemists Glycemic Carbohydrate Definition Committee, 2007), expresses relative glycemic potential in grams of glycemic glucose equivalents (GGEs) per specified amount of food. Therefore, GGE behaves as a food component, and (relative) glycemic impact (RGI) is the GGE intake responsible for a glycemic response. RGI differs from glycemic index (GI) because it refers to food and depends on food intake, whereas GI refers to carbohydrate and is a unitless index value unresponsive to food intake. Glycemic load (GL) is the theoretical cumulative exposure to glycemia over a period of time and is derived from GI as GI x carbohydrate intake. Contracted to a single intake of food, GL approximates RGI but cannot be accurately expressed in terms of glucose equivalents, because GI is measured by using equal carbohydrate intakes with usually unequal responses. RGI, on the other hand, is based on relative food and reference quantities required to give equal glycemic responses and so is accurately expressed as GGE. The properties of GGE allow it to be used as a virtual food component in food labeling and in food-composition databases linked to nutrition management systems to represent the glycemic impact of foods alongside nutrient intakes. GGE can also indicate carbohydrate quality when used to compare foods in equal carbohydrate food groupings.

  2. Evaluation of the biofidelity of the HIII and MIL-Lx lower leg surrogates under axial impact loading.

    PubMed

    Quenneville, Cheryl E; Dunning, Cynthia E

    2012-01-01

    Lower leg injury risk is commonly assessed using an anthropomorphic test device (ATD). The current standard leg (the HIII) has been shown to have low biofidelity due to its geometry and material properties. A new surrogate (the MIL-Lx) was developed to address these issues, specifically for anti-vehicular mine blast scenarios but with potential applications to high-force crashes in the automotive industry. Before it is adopted for use, the MIL-Lx must be evaluated under impact loading to ensure that it represents the natural lower leg response. Axial impact loads were applied to both the HIII and the MIL-Lx at impact velocities of 2 to 7 m/s using a pneumatic impacting device. Testing was also conducted with the foot removed from both surrogates to enable comparison with previous tests of isolated cadaveric tibias at noninjurious and injurious (i.e., fracture) levels. To evaluate the effect of a boot on load attenuation, the HIII was impacted with and without a hiking boot. Forces in the MIL-Lx were between 25 and 100 percent of those in the HIII (depending on impact conditions). The use of a boot reduced the peak force by approximately 65 percent at the highest impact velocities. The MIL-Lx fit the data from noninjurious cadaveric tibia tests with R(2) = 0.83. The MIL-Lx is a new surrogate that represents the response of the natural tibia under axial impact loading better than the HIII. The inclusion of a boot has a significant effect on loads in the leg and may influence injury assessment results. The MIL-Lx will be a useful tool for predicting lower leg injury risk over a wide range of impact velocities.

  3. Biomechanics of Human Thoracolumbar Spinal Column Trauma from Vertical Impact Loading

    PubMed Central

    Yoganandan, Narayan; Arun, Mike W. J.; Stemper, Brian D.; Pintar, Frank A.; Maiman, Dennis J.

    2013-01-01

    Recent studies suggest that dorsal spine injuries occur in motor vehicle crashes to restrained occupants. Compression/compression-flexion injuries occur in frontal crashes due to seat pan and vertical loading. While injuries, mechanisms and tolerances for neck injuries have been determined, thoraco-lumbar spine data are very limited. The objective of the study was to determine the biomechanical characteristics associated with such spinal injuries due to vertical loading. Upper thoracic (T2–T6), lower thoracic (T7–T11) and lumbar (T12-L5) columns from post mortem human surrogates were procured, fixed at the ends and dropped from three heights: the first two impacts designed as non-failure tests and the final was the failure test. Intermittent evaluations consisted of palpations and x-rays. Injuries were assessed using posttest x-rays and computed tomography scans. The age, stature, total body mass and body mass index of three PMHS were: 50 years, 164 cm, 66.9 kg, and 24.7 kg/m2. The mean peak forces from 24 tests for the upper and lower thoracic and lumbar spines for varying drop heights ranged from 1.6 to 4.3, 1.3 to 5.1, and 1.3 to 6.7 kN, respectively. All peak forces increased with increasing drop heights. Injuries to the three spines included unstable vertebral body and posterior element (bipedicular and lamina) compression fractures and posterior complex disruptions. Logistic regression analysis indicated that peak forces of 3.4 and 3.7 kN are associated with 50% probability of fracture. These results indicate the initial tolerance limits of dorsal spines under vertical loading. PMID:24406955

  4. Biomechanics of human thoracolumbar spinal column trauma from vertical impact loading.

    PubMed

    Yoganandan, Narayan; Arun, Mike W J; Stemper, Brian D; Pintar, Frank A; Maiman, Dennis J

    2013-01-01

    Recent studies suggest that dorsal spine injuries occur in motor vehicle crashes to restrained occupants. Compression/compression-flexion injuries occur in frontal crashes due to seat pan and vertical loading. While injuries, mechanisms and tolerances for neck injuries have been determined, thoraco-lumbar spine data are very limited. The objective of the study was to determine the biomechanical characteristics associated with such spinal injuries due to vertical loading. Upper thoracic (T2-T6), lower thoracic (T7-T11) and lumbar (T12-L5) columns from post mortem human surrogates were procured, fixed at the ends and dropped from three heights: the first two impacts designed as non-failure tests and the final was the failure test. Intermittent evaluations consisted of palpations and x-rays. Injuries were assessed using posttest x-rays and computed tomography scans. The age, stature, total body mass and body mass index of three PMHS were: 50 years, 164 cm, 66.9 kg, and 24.7 kg/m(2). The mean peak forces from 24 tests for the upper and lower thoracic and lumbar spines for varying drop heights ranged from 1.6 to 4.3, 1.3 to 5.1, and 1.3 to 6.7 kN, respectively. All peak forces increased with increasing drop heights. Injuries to the three spines included unstable vertebral body and posterior element (bipedicular and lamina) compression fractures and posterior complex disruptions. Logistic regression analysis indicated that peak forces of 3.4 and 3.7 kN are associated with 50% probability of fracture. These results indicate the initial tolerance limits of dorsal spines under vertical loading.

  5. Reverberation Chamber Uniformity Validation and Radiated Susceptibility Test Procedures for the NASA High Intensity Radiated Fields Laboratory

    NASA Technical Reports Server (NTRS)

    Koppen, Sandra V.; Nguyen, Truong X.; Mielnik, John J.

    2010-01-01

    The NASA Langley Research Center's High Intensity Radiated Fields Laboratory has developed a capability based on the RTCA/DO-160F Section 20 guidelines for radiated electromagnetic susceptibility testing in reverberation chambers. Phase 1 of the test procedure utilizes mode-tuned stirrer techniques and E-field probe measurements to validate chamber uniformity, determines chamber loading effects, and defines a radiated susceptibility test process. The test procedure is segmented into numbered operations that are largely software controlled. This document is intended as a laboratory test reference and includes diagrams of test setups, equipment lists, as well as test results and analysis. Phase 2 of development is discussed.

  6. Analysis of progressive damage in thin circular laminates due to static-equivalent impact loads

    NASA Technical Reports Server (NTRS)

    Shivakumar, K. N.; Elber, W.; Illg, W.

    1983-01-01

    Clamped circular graphite/epoxy plates (25.4, 38.1, and 50.8 mm radii) with an 8-ply quasi-isotropic layup were analyzed for static-equivalent impact loads using the minimum-total-potential-energy method and the von Karman strain-displacement equations. A step-by-step incremental transverse displacement procedure was used to calculate plate load and ply stresses. The ply failure region was calculated using the Tsai-Wu criterion. The corresponding failure modes (splitting and fiber failure) were determined using the maximum stress criteria. The first-failure mode was splitting and initiated first in the bottom ply. The splitting-failure thresholds were relatively low and tended to be lower for larger plates than for small plates. The splitting-damage region in each ply was elongated in its fiber direction; the bottom ply had the largest damage region. The calculated damage region for the 25.4-mm-radius plate agreed with limited static test results from the literature.

  7. Impact of traffic intensity and pavement aggregate size on road dust particles loading

    NASA Astrophysics Data System (ADS)

    Amato, F.; Pandolfi, M.; Alastuey, A.; Lozano, A.; Contreras González, J.; Querol, X.

    2013-10-01

    Road dust emissions severely hamper PM10 urban air quality and their burden is expected to increase relatively to primary motor exhaust emissions. Beside the large influence of climate and meteorology, the emission potential varies widely also from one road to another due to numerous factors such as traffic conditions, pavement type and external sources. Nevertheless none of these factors is sufficiently known for a reliable description in emission modelling and for decision making in air quality management. In this study we carried out intensive road dust measurement campaigns in South Spain, with the aim of investigating the relationship between emission potential (i.e. road dust load) and traffic intensity, pavement aggregate size and distance from braking zones. Results indicate that, while no impact from braking activity can be drawn on the bulk road dust mass, an increase in traffic intensity or mean pavement aggregate size clearly reduce the single vehicle emission potential.

  8. Impacts of Providing Inertial Response on Dynamic Loads of Wind Turbine Drivetrains: Preprint

    SciTech Connect

    Girsang, I. P.; Dhupia, J.; Singh, M.; Gevorgian, V.; Muljadi, E.; Jonkman, J.

    2014-09-01

    There has been growing demand from the power industry for wind power plants to support power system operations. One such requirement is for wind turbines to provide ancillary services in the form of inertial response. When the grid frequency drops, it is essential for wind turbine generators (WTGs) to inject kinetic energy stored in their inertia into the grid to help arrest the frequency decline. However, the impacts of inertial response on the structural loads of the wind turbine have not been given much attention. To bridge this gap, this paper utilizes a holistic model for both fixed-speed and variable-speed WTGs by integrating the aeroelastic wind turbine model in FAST, developed by the National Renewable Energy Laboratory, with the electromechanical drivetrain model in SimDriveline and SimPowerSystems.

  9. Shock loading in biofilters: impact on biodegradation activity distribution and resilience capacity.

    PubMed

    Cabrol, L; Malhautier, L; Poly, F; Lepeuple, A S; Fanlo, J L

    2009-01-01

    A synthetic contaminated gas was generated, representative of gaseous emissions from sludge composting. It was composed of six volatile organic compounds (aldehyde, ketones, esters, sulphur compound) in an ammoniacal matrix. The gaseous stream was purified by biofiltration, in pilot scale biofilters filled with pine bark woodchips as organic carrier for biomass colonization. After reaching a constant high efficiency, with complete removal, the system was disturbed by transient loading shocks. The impact of perturbations was assessed by both performance evaluation (i.e. contaminant removal) and microbial behaviour. The microbial community was analysed in terms of density. The resilience of functional component following a perturbation was evaluated. This work highlighted the longitudinal distribution of both biodegradation activities and biomass density.

  10. High-intensive femtosecond singular pulses in Kerr dielectrics.

    PubMed

    Khasanov, Oleg; Smirnova, Tatyana; Fedotova, Olga; Rusetsky, Grigory; Romanov, Oleg

    2012-04-01

    The nonlinear dynamics of a high-power femtosecond singular pulse in Kerr media are analyzed numerically upon optically induced ionization. We examine the plasma inertia impact to stable propagation of optical vortices. Multifoci behavior of vortices in medium are revealed. Next we numerically demonstrate that inertial character of plasma formation provides a quasi-soliton regime of vortex propagation resistant to symmetry-breaking perturbation.

  11. Low- Versus High-Intensity Plyometric Exercise During Rehabilitation After Anterior Cruciate Ligament Reconstruction.

    PubMed

    Chmielewski, Terese L; George, Steven Z; Tillman, Susan M; Moser, Michael W; Lentz, Trevor A; Indelicato, Peter A; Trumble, Troy N; Shuster, Jonathan J; Cicuttini, Flavia M; Leeuwenburgh, Christiaan

    2016-03-01

    Plyometric exercise is used during rehabilitation after anterior cruciate ligament (ACL) reconstruction to facilitate the return to sports participation. However, clinical outcomes have not been examined, and high loads on the lower extremity could be detrimental to knee articular cartilage. To compare the immediate effect of low- and high-intensity plyometric exercise during rehabilitation after ACL reconstruction on knee function, articular cartilage metabolism, and other clinically relevant measures. Randomized controlled trial; Level of evidence, 2. Twenty-four patients who underwent unilateral ACL reconstruction (mean, 14.3 weeks after surgery; range, 12.1-17.7 weeks) were assigned to 8 weeks (16 visits) of low- or high-intensity plyometric exercise consisting of running, jumping, and agility activities. Groups were distinguished by the expected magnitude of vertical ground-reaction forces. Testing was conducted before and after the intervention. Primary outcomes were self-reported knee function (International Knee Documentation Committee [IKDC] subjective knee form) and a biomarker of articular cartilage degradation (urine concentrations of crosslinked C-telopeptide fragments of type II collagen [uCTX-II]). Secondary outcomes included additional biomarkers of articular cartilage metabolism (urinary concentrations of the neoepitope of type II collagen cleavage at the C-terminal three-quarter-length fragment [uC2C], serum concentrations of the C-terminal propeptide of newly formed type II collagen [sCPII]) and inflammation (tumor necrosis factor-α), functional performance (maximal vertical jump and single-legged hop), knee impairments (anterior knee laxity, average knee pain intensity, normalized quadriceps strength, quadriceps symmetry index), and psychosocial status (kinesiophobia, knee activity self-efficacy, pain catastrophizing). The change in each measure was compared between groups. Values before and after the intervention were compared with the groups

  12. Impacts of Declining Mississippi River Sediment Load on Subaqueous Delta Front Sedimentation and Geomorphology

    NASA Astrophysics Data System (ADS)

    Maloney, J. M.; Bentley, S. J.; Xu, K.; Georgiou, I. Y.; Miner, M. D.

    2016-02-01

    The Mississippi River delta system is undergoing unprecedented changes due to the effects of climate change and anthropogenic alterations to the river and its delta. Since the 1950s, the suspended sediment load of the Mississippi River has decreased by approximately 50% due to the construction of >50,000 dams in the Mississippi basin. The impact of this decreased sediment load has been observed in subaerial environments, but the impact on sedimentation and geomorphology of the subaqueous delta front has yet to be examined. To identify historic trends in sedimentation patterns, we compiled bathymetric datasets, including historical charts, industry and academic surveys, and NOAA data, collected between 1764 and 2009. Sedimentation rates are variable across the delta front, but are highest near the mouth of Southwest Pass, which carries the largest percentage of Mississippi River flow and sediment into the Gulf of Mexico. The progradation rate of Southwest Pass (measured at the 10 m depth contour) has slowed from 67 m/yr between 1764 and 1940 to 26 m/yr between 1940 and 1979, with evidence of further deceleration from 1979-2009. Decreased rates of progradation are also observed at South Pass and Pass A Loutre, with the 10 m contour retreating at rates >20 m/yr at both passes. Advancement of the delta front also decelerated in deeper water (15-90 m) offshore from Southwest Pass. In this area, from 1940-1979, depth contours advanced seaward 30 m/yr, but rates declined from 1979-2005. Furthermore, over the same area, the sediment accumulation rate decreased by 81% for the same period. The Mississippi River delta front appears to be entering a phase of decline, which will likely be accelerated by future upstream management practices. This decline has implications for offshore ecosystems, biogeochemical cycling, pollutant dispersal, mudflow hazard, and the continued use of the delta as an economic and population center.

  13. Max Tech and Beyond: High-Intensity Discharge Lamps

    SciTech Connect

    Scholand, Michael

    2012-04-01

    High-intensity discharge (HID) lamps are most often found in industrial and commercial applications, and are the light source of choice in street and area lighting, and sports stadium illumination. HID lamps are produced in three types - mercury vapor (MV), high pressure sodium (HPS) and metal halide (MH). Of these, MV and MH are considered white-light sources (although the MV exhibits poor color rendering) and HPS produces a yellow-orange color light. A fourth lamp, low-pressure sodium (LPS), is not a HID lamp by definition, but it is used in similar applications and thus is often grouped with HID lamps. With the notable exception of MV which is comparatively inefficient and in decline in the US from both a sales and installed stock point of view; HPS, LPS and MH all have efficacies over 100 lumens per watt. The figure below presents the efficacy trends over time for commercially available HID lamps and LPS, starting with MV and LPS in 1930's followed by the development of HPS and MH in the 1960's. In HID lamps, light is generated by creating an electric arc between two electrodes in an arc tube. The particles in the arc are partially ionized, making them electrically conductive, and a light-emitting 'plasma' is created. This arc occurs within the arc tube, which for most HID lamps is enclosed within an evacuated outer bulb that thermally isolates and protects the hot arc tube from the surroundings. Unlike a fluorescent lamp that produces visible light through down-converting UV light with phosphors, the arc itself is the light source in an HID lamp, emitting visible radiation that is characteristic of the elements present in the plasma. Thus, the mixture of elements included in the arc tube is one critical factor determining the quality of the light emitted from the lamp, including its correlated color temperature (CCT) and color rendering index (CRI). Similar to fluorescent lamps, HID lamps require a ballast to start and maintain stable operating conditions, and

  14. Effects of Anabolic Steroids and High-Intensity Aerobic Exercise on Skeletal Muscle of Transgenic Mice

    PubMed Central

    Fontana, Karina; Campos, Gerson E. R.; Staron, Robert S.; da Cruz-Höfling, Maria Alice

    2013-01-01

    In an attempt to shorten recovery time and improve performance, strength and endurance athletes occasionally turn to the illicit use of anabolic-androgenic steroids (AAS). This study evaluated the effects of AAS treatment on the muscle mass and phenotypic characteristics of transgenic mice subjected to a high-intensity, aerobic training program (5d/wk for 6 weeks). The transgenic mice (CETP+/-LDLr-/+) were engineered to exhibit a lipid profile closer to humans. Animals were divided into groups of sedentary (Sed) and/or training (Ex) mice (each treated orally with AAS or gum arabic/vehicle: Sed-C, Sed-M, ex-C, ex-M). The effects of AAS (mesterolone: M) on specific phenotypic adaptations (muscle wet weight, cross-sectional area, and fiber type composition) in three hindlimb muscles (soleus:SOL, tibialis anterior:TA and gastrocnemius:GAS) were assessed. In order to detect subtle changes in fiber type profile, the entire range of fiber types (I, IC, IIAC, IIA, IIAD, IID, IIDB, IIB) was delineated using mATPase histochemistry. Body weight gain occurred throughout the study for all groups. However, the body weight gain was significantly minimized with exercise. This effect was blunted with mesterolone treatment. Both AAS treatment (Sed-M) and high-intensity, aerobic training (ex-C) increased the wet weights of all three muscles and induced differential hypertrophy of pure and hybrid fibers. Combination of AAS and training (ex-M) resulted in enhanced hypertrophy. In the SOL, mesterolone treatment (Sed-M and ex-M) caused dramatic increases in the percentages of fiber types IC, IIAC, IIAD, IID, with concomitant decrease in IIA, but had minimal impact on fiber type percentages in the predominantly fast muscles. Overall, the AAS-induced differential adaptive changes amounted to significant fiber type transformations in the fast-to-slow direction in SOL. AAS treatment had a significant effect on muscle weights and fiber type composition in SOL, TA and GAS which was even

  15. Impact of high versus low fixed loads and non-linear training loads on muscle hypertrophy, strength and force development.

    PubMed

    Fink, Julius; Kikuchi, Naoki; Yoshida, Shou; Terada, Kentaro; Nakazato, Koichi

    2016-01-01

    In this study, we investigated the effects of resistance training protocols with different loads on muscle hypertrophy and strength. Twenty-one participants were randomly assigned to 1 of 3 (n = 7 for each) resistance training (RT) protocols to failure: High load 80 % 1RM (8-12 repetitions) (H group), low load 30 % 1RM (30-40 repetitions) (L group) and a mixed RT protocol (M group) in which the participants switch from H to L every 2 weeks. RT consisted of three sets of unilateral preacher curls performed with the left arm 3 times/week with 90 s rest intervals between sets. The right arm served as control. Maximum voluntary contraction (MVC) of the elbow flexors (elbow angle: 90°) and rate of force development (RFD, 0-50, 50-100, 100-200 and 200-300 ms) were measured. Cross-sectional area (CSA) of the elbow flexors was measured via magnetic resonance imaging (MRI). All measurements were conducted before and after the 8 weeks of RT (72-96 h after the last RT). Statistical evaluations were performed with two-way repeated measures (time × group). After 8 weeks of 3 weekly RT sessions, significant increases in the left elbow flexor CSA [H: 9.1 ± 6.4 % (p = 0.001), L: 9.4 ± 5.3 % (p = 0.001), M: 8.8 ± 7.9 % (p = 0.001)] have been observed in each group, without significant differences between groups. Significant changes in elbow flexor isometric MVC have been observed in the H group (26.5 ± 27.0 %, p = 0.028), while no significant changes have been observed in the M (11.8 ± 36.4 %, p = 0.26) and L (4.6 ± 23.9 %, p = 0.65) groups. RFD significantly increased during the 50-100 ms phase in the H group only (p = 0.049). We conclude that, as long as RT is conducted to failure, training load might not affect muscle hypertrophy in young men. Nevertheless, strength and RFD changes seem to be load-dependent. Furthermore, a non-linear RT protocol switching loads every 2 weeks might not lead to superior muscle hypertrophy nor

  16. Impact induced failure of cartilage-on-bone following creep loading: a microstructural and fracture mechanics study.

    PubMed

    Thambyah, Ashvin; Zhang, Geran; Kim, Woong; Broom, Neil D

    2012-10-01

    Cartilage-on-bone samples obtained from healthy bovine patellae, with or without prior static compression (i.e. creep) at 2MPa for 3h, were delivered a single impact via an instrumented pendulum indenter at a velocity of 1.13m/s and an energy of 2.2J. Mechanical data was obtained and microstructural assessment of the region of failure was carried out using differential interference contrast (DIC) optical imaging. In addition, a fibrillar-level structural analysis using scanning electron microscopy (SEM) was conducted on a control batch of non-impacted samples that were subjected to either creep or non-creep loading protocols. Arising from the impact event the deepest levels of crack penetration into the articular cartilage occurred in those samples subjected to prior creep loading. Further the crack depth was inversely proportional to the rebound velocity of the indenter. By contrast, those impacted samples not subjected to prior creep loading had only short obliquely patterned microcracks confined to the upper one-third of the full cartilage depth. Ultrastructurally the creep-loaded cartilage matrix exhibited a substantial radial collapse or compaction of the fibrillar network in its primary radial zone. The increase in crack length in the prior creep-loaded cartilage is consistent with a reduction in its dissipative properties as indicated by a reduction in rebound velocity. An interpretation is offered in terms of classical fracture mechanics theory. Copyright © 2012 Elsevier Ltd. All rights reserved.

  17. Nakagami imaging for detecting thermal lesions induced by high-intensity focused ultrasound in tissue.

    PubMed

    Rangraz, Parisa; Behnam, Hamid; Tavakkoli, Jahan

    2014-01-01

    High-intensity focused ultrasound induces focalized tissue coagulation by increasing the tissue temperature in a tight focal region. Several methods have been proposed to monitor high-intensity focused ultrasound-induced thermal lesions. Currently, ultrasound imaging techniques that are clinically used for monitoring high-intensity focused ultrasound treatment are standard pulse-echo B-mode ultrasound imaging, ultrasound temperature estimation, and elastography-based methods. On the contrary, the efficacy of two-dimensional Nakagami parametric imaging based on the distribution of the ultrasound backscattered signals to quantify properties of soft tissue has recently been evaluated. In this study, ultrasound radio frequency echo signals from ex vivo tissue samples were acquired before and after high-intensity focused ultrasound exposures and then their Nakagami parameter and scaling parameter of Nakagami distribution were estimated. These parameters were used to detect high-intensity focused ultrasound-induced thermal lesions. Also, the effects of changing the acoustic power of the high-intensity focused ultrasound transducer on the Nakagami parameters were studied. The results obtained suggest that the Nakagami distribution's scaling and Nakagami parameters can effectively be used to detect high-intensity focused ultrasound-induced thermal lesions in tissue ex vivo. These parameters can also be used to understand the degree of change in tissue caused by high-intensity focused ultrasound exposures, which could be interpreted as a measure of degree of variability in scatterer concentration in various parts of the high-intensity focused ultrasound lesion.

  18. Time course of strength adaptations following high-intensity resistance training in individuals with multiple sclerosis.

    PubMed

    Manca, A; Dvir, Z; Dragone, D; Mureddu, G; Bua, G; Deriu, Franca

    2017-04-01

    No evidence exists regarding the time course and clinical relevance of muscle strength improvements following resistance training in people with multiple sclerosis (PwMS). The purpose of this study was to investigate the temporal course and the clinical meaningfulness of the changes in strength induced by high-intensity resistance training and whether these changes impact on muscle endurance to fatigue and functional outcomes. PwMS with predominantly unilateral hyposthenia of the ankle dorsiflexors underwent a 6-week isokinetic training of the more affected ankle dorsiflexion muscles. Maximal strength was measured at baseline, during the training on a weekly basis, at the end of the intervention (POST) and at the 12-week follow-up. Muscle endurance to fatigue, mobility and walking outcomes were assessed at baseline, POST and follow-up. Reproducibility and responsiveness analyses were performed. Significant gains in muscle strength were already detected after 3 weeks of training with no further improvements in the following weeks. These improvements exceeded the cutoff values for relevant changes and were also positively correlated to improved muscle endurance to fatigue and mobility measures. None of the observed changes in muscle performance and functional outcomes was retained at the follow-up. Preliminary evidence showed that 3 weeks of high-intensity resistance training induces consistent and meaningful improvements in muscle performance of the ankle dorsiflexors in PwMS. These findings may have practical dose-response and cost-effectiveness implications in the management of MS-induced muscle weakness, potentially enhancing the understanding of the response to training exhibited by PwMS. ClinicalTrials.gov identifier NCT02010398; December 2013.

  19. Probabilistic analysis of local ice pressures. [Calculation of ice load and impact effects on offshore platforms

    SciTech Connect

    Jordaan, I.J.; Brown, P.W. ); Maes, M.A.; Hermans, I.P. . Dept. of Mathematics and Statistics)

    1993-02-01

    Extensive work in recent years has been carried out on the calculation of global ice loads on a probabilistic basis. An analysis method is presented for local ice pressures, which yields values of pressure for specific values of exceedance probability. In developing this method, particular attention has been paid to problems of exposure (length, position and number of impacts), as well as the area of exposure (area within area versus nominal contact area). The solution has been formulated for a series of discrete impacts, e.g., rams by a vessel, or a series of periods of continuous interactions. Data for the MV CANMAR Kigoriak and USCGC Polar Sea were ranked and curves were fitted through the tail of probability plots for three panel sizes. This allowed determination of exceedance probabilities of the design coefficients for pressure as a junction of area. The method developed was then applied to an example for a ship based on the data and expected number of rams per year. Formulas useful in the design of structures in ice are presented.

  20. The Impact of Environmental and Endogenous Damage on Somatic Mutation Load in Human Skin Fibroblasts

    PubMed Central

    Saini, Natalie; Chan, Kin; Grimm, Sara A.; Dai, Shuangshuang; Fargo, David C.; Kaufmann, William K.; Taylor, Jack A.; Lee, Eunjung; Cortes-Ciriano, Isidro; Park, Peter J.; Schurman, Shepherd H.; Malc, Ewa P.; Mieczkowski, Piotr A.

    2016-01-01

    Accumulation of somatic changes, due to environmental and endogenous lesions, in the human genome is associated with aging and cancer. Understanding the impacts of these processes on mutagenesis is fundamental to understanding the etiology, and improving the prognosis and prevention of cancers and other genetic diseases. Previous methods relying on either the generation of induced pluripotent stem cells, or sequencing of single-cell genomes were inherently error-prone and did not allow independent validation of the mutations. In the current study we eliminated these potential sources of error by high coverage genome sequencing of single-cell derived clonal fibroblast lineages, obtained after minimal propagation in culture, prepared from skin biopsies of two healthy adult humans. We report here accurate measurement of genome-wide magnitude and spectra of mutations accrued in skin fibroblasts of healthy adult humans. We found that every cell contains at least one chromosomal rearrangement and 600–13,000 base substitutions. The spectra and correlation of base substitutions with epigenomic features resemble many cancers. Moreover, because biopsies were taken from body parts differing by sun exposure, we can delineate the precise contributions of environmental and endogenous factors to the accrual of genetic changes within the same individual. We show here that UV-induced and endogenous DNA damage can have a comparable impact on the somatic mutation loads in skin fibroblasts. Trial Registration ClinicalTrials.gov NCT01087307 PMID:27788131

  1. The Impact of Environmental and Endogenous Damage on Somatic Mutation Load in Human Skin Fibroblasts.

    PubMed

    Saini, Natalie; Roberts, Steven A; Klimczak, Leszek J; Chan, Kin; Grimm, Sara A; Dai, Shuangshuang; Fargo, David C; Boyer, Jayne C; Kaufmann, William K; Taylor, Jack A; Lee, Eunjung; Cortes-Ciriano, Isidro; Park, Peter J; Schurman, Shepherd H; Malc, Ewa P; Mieczkowski, Piotr A; Gordenin, Dmitry A

    2016-10-01

    Accumulation of somatic changes, due to environmental and endogenous lesions, in the human genome is associated with aging and cancer. Understanding the impacts of these processes on mutagenesis is fundamental to understanding the etiology, and improving the prognosis and prevention of cancers and other genetic diseases. Previous methods relying on either the generation of induced pluripotent stem cells, or sequencing of single-cell genomes were inherently error-prone and did not allow independent validation of the mutations. In the current study we eliminated these potential sources of error by high coverage genome sequencing of single-cell derived clonal fibroblast lineages, obtained after minimal propagation in culture, prepared from skin biopsies of two healthy adult humans. We report here accurate measurement of genome-wide magnitude and spectra of mutations accrued in skin fibroblasts of healthy adult humans. We found that every cell contains at least one chromosomal rearrangement and 600–13,000 base substitutions. The spectra and correlation of base substitutions with epigenomic features resemble many cancers. Moreover, because biopsies were taken from body parts differing by sun exposure, we can delineate the precise contributions of environmental and endogenous factors to the accrual of genetic changes within the same individual. We show here that UV-induced and endogenous DNA damage can have a comparable impact on the somatic mutation loads in skin fibroblasts. Trial Registration: ClinicalTrials.gov NCT01087307.

  2. Numerical simulations of the occupant head response in an infantry vehicle under blunt impact and blast loading conditions.

    PubMed

    Sevagan, Gopinath; Zhu, Feng; Jiang, Binhui; Yang, King H

    2013-07-01

    This article presents the results of a finite element simulation on the occupant head response in an infantry vehicle under two separated loading conditions: (1) blunt impact and (2) blast loading conditions. A Hybrid-III dummy body integrated with a previously validated human head model was used as the surrogate. The biomechanical response of the head was studied in terms of head acceleration due to the impact by a projectile on the vehicle and intracranial pressure caused by blast wave. A series of parametric studies were conducted on the numerical model to analyze the effect of some key parameters, such as seat configuration, impact velocity, and boundary conditions. The simulation results indicate that a properly designed seat and internal surface of the infantry vehicle can play a vital role in reducing the risk of head injury in the current scenarios. Comparison of the kinematic responses under the blunt impact and blast loading conditions reveals that under the current loading conditions, the acceleration pulse in the blast scenario has much higher peak values and frequency than blunt impact case, which may reflect different head response characteristics.

  3. Effect on structure and mechanical property of tungsten irradiated by high intensity pulsed ion beam

    NASA Astrophysics Data System (ADS)

    Mei, Xianxiu; Zhang, Xiaonan; Liu, Xiaofei; Wang, Younian

    2017-09-01

    The anti-thermal radiation performance of tungsten was investigated by high intensity pulsed ion beam technology. The ion beam was mainly composed of Cn+ (70%) and H+ (30%) at an acceleration voltage of 250 kV under different energy densities for different number of pulses. GIXRD analysis showed that no obvious phase structural changes occurred on the tungsten, and microstress generated. SEM analysis exhibited that there was no apparent irradiation damage on the surface of tungsten at the low irradiation frequency (3 times and 10 times) and at the low energy density (0.25 J/cm2 and 0.7 J/cm2). Cracks appeared on the surface of tungsten after 100-time and 300-time irradiation. Shedding phenomenon even appeared on the surface of tungsten at the energy densities of 1.4 J/cm2 and 2.0 J/cm2. The surface nano-hardness of tungsten decreased with the increase of the pulse times and the energy density. The tungsten has good anti-thermal radiation properties under certain heat load environment.

  4. Effects of inspiratory muscle training upon recovery time during high intensity, repetitive sprint activity.

    PubMed

    Romer, L M; McConnell, A K; Jones, D A

    2002-07-01

    The present study examined the influence of specific inspiratory muscle training (IMT) upon recovery time during repetitive sprint activity, as well as the physiological and perceptual responses to fixed intensity shuttle running. Using a double-blind placebo-controlled design, 24 male repetitive sprint athletes were assigned randomly to either an IMT (n = 12) or placebo (n = 12) group. The self-selected recovery time during a repetitive sprint test and the physiological response to submaximal endurance exercise were determined. Following completion of baseline and pre-intervention measures, the IMT group performed 30 inspiratory efforts twice daily against a resistance equivalent to 50 % maximum inspiratory mouth pressure (MIP) for 6 wk. The placebo group performed 60 breaths once daily, for 6 wk, at a resistance equivalent to 15 % MIP, a load known to elicit negligible changes in respiratory muscle function. The IMT group improved total recovery time during the repetitive sprint test by 6.2 +/- 1.1 % (mean +/- SEM) above the changes noted for the placebo group (p = 0.006). Blood lactate and perceptual responses to submaximal exercise were also significantly attenuated following IMT (p high intensity, intermittent exercise in repetitive sprint athletes.

  5. Radiation control in the intensive care unit for high intensity iridium-192 brain implants

    SciTech Connect

    Sewchand, W.; Drzymala, R.E.; Amin, P.P.; Salcman, M.; Salazar, O.M.

    1987-04-01

    A bedside lead cubicle was designed to minimize the radiation exposure of intensive care unit staff during routine interstitial brain irradiation by removable, high intensity iridium-192. The cubicle shields the patient without restricting intensive care routines. The design specifications were confirmed by exposure measurements around the shield with an implanted anthropomorphic phantom simulating the patient situation. The cubicle reduces the exposure rate around an implant patient by as much as 90%, with the exposure level not exceeding 0.1 mR/hour/mg of radium-equivalent /sup 192/Ir. Evaluation of data accumulated for the past 3 years has shown that the exposure levels of individual attending nurses are 0.12 to 0.36 mR/mg of radium-equivalent /sup 192/Ir per 12-hour shift. The corresponding range for entire nursing teams varies between 0.18 and 0.26. A radiation control index (exposure per mg of radium-equivalent /sup 192/Ir per nurse-hour) is thus defined for individual nurses and nursing teams; this index is a significant guide to the planning of nurse rotations for brain implant patients with various /sup 192/Ir loads. The bedside shield reduces exposure from /sup 192/Ir implants by a factor of about 20, as expected, and the exposure from the lower energy radioisotope iodine-125 is barely detectable.

  6. Reversible permeabilization using high-intensity femtosecond laser pulses: applications to biopreservation.

    PubMed

    Kohli, Vikram; Acker, Jason P; Elezzabi, Abdulhakem Y

    2005-12-30

    Non-invasive manipulation of live cells is important for cell-based therapeutics. Herein we report on the uniqueness of using high-intensity femtosecond laser pulses for reversibly permeabilizing mammalian cells for biopreservation applications. When mammalian cells were suspended in a impermeable hyperosmotic cryoprotectant sucrose solution, femtosecond laser pulses were used to transiently permeabilize cells for cytoplasmic solute uptake. The kinetics of cells exposed to 0.2, 0.3, 0.4, and 0.5 M sucrose, following permeabilization, were measured using video microscopy, and post-permeabilization survival was determined by a dual fluorescence membrane integrity assay. Using appropriate laser parameters, we observed the highest cell survival for 0.2 M sucrose solution (>90%), with a progressive decline in cell survival towards higher concentrations. Using diffusion equations describing the transport of solutes, the intracellular osmolarity at the inner surface of the membrane (x = 10 nm) and to a diffusive length of x = 10 microm was estimated, and a high loading efficiency (>98% for x = 10 nm and >70% for x = 10 microm) was calculated for cells suspended in 0.2 M sucrose. This is the first report of using femtosecond laser pulses for permeabilizing cells in the presence of cryoprotectants for biopreservation applications. Copyright 2005 Wiley Periodicals, Inc

  7. High-intensity interval training acutely alters plasma adipokine levels in young overweight/obese women.

    PubMed

    Vardar, Selma Arzu; Karaca, Aziz; Güldiken, Sibel; Palabıyık, Orkide; Süt, Necdet; Demir, Ahmet Muzaffer

    2017-08-31

    The aim of this study was to investigate the plasma adipokine responses to high-intensity interval training (HIT) in overweight/obese women. Twelve women (age 21.7 ± 3.8 years) completed a 19 days of HIT comprising six session of 4-6 repeats of a Wingate test (0.065 kg load/kg). Plasma adipokine levels were measured before exercise, and at 5 and 90 min after exercise on the first and the last training days. Adiponectin was higher at 5 min than 90 min post-exercise (11.7 ± 7.3 and 10.5 ± 5.8 ng/ml; p = .01) in the first exercise day. Leptin decreased 5 min after exercise (23.6 ± 13.2 vs. baseline 27.8 ± 14.4 ng/ml; p < .01) and remained depressed following 90 min (p < .01). The changes in adiponectin and leptin concentrations were similar on the first and last exercise days. No consistent effect was found on resistin concentration. Future studies are required to disclose the functional consequences of these alterations in plasma adipokine levels.

  8. Impacts of rising air temperatures on electric transmission ampacity and peak electricity load in the United States

    NASA Astrophysics Data System (ADS)

    Bartos, Matthew; Chester, Mikhail; Johnson, Nathan; Gorman, Brandon; Eisenberg, Daniel; Linkov, Igor; Bates, Matthew

    2016-11-01

    Climate change may constrain future electricity supply adequacy by reducing electric transmission capacity and increasing electricity demand. The carrying capacity of electric power cables decreases as ambient air temperatures rise; similarly, during the summer peak period, electricity loads typically increase with hotter air temperatures due to increased air conditioning usage. As atmospheric carbon concentrations increase, higher ambient air temperatures may strain power infrastructure by simultaneously reducing transmission capacity and increasing peak electricity load. We estimate the impacts of rising ambient air temperatures on electric transmission ampacity and peak per-capita electricity load for 121 planning areas in the United States using downscaled global climate model projections. Together, these planning areas account for roughly 80% of current peak summertime load. We estimate climate-attributable capacity reductions to transmission lines by constructing thermal models of representative conductors, then forcing these models with future temperature projections to determine the percent change in rated ampacity. Next, we assess the impact of climate change on electricity load by using historical relationships between ambient temperature and utility-scale summertime peak load to estimate the extent to which climate change will incur additional peak load increases. We find that by mid-century (2040-2060), increases in ambient air temperature may reduce average summertime transmission capacity by 1.9%-5.8% relative to the 1990-2010 reference period. At the same time, peak per-capita summertime loads may rise by 4.2%-15% on average due to increases in ambient air temperature. In the absence of energy efficiency gains, demand-side management programs and transmission infrastructure upgrades, these load increases have the potential to upset current assumptions about future electricity supply adequacy.

  9. The impact of emotion on the perception of graded magnitudes of respiratory resistive loads.

    PubMed

    Tsai, Hsiu-Wen; Chan, Pei-Ying; von Leupoldt, Andreas; Davenport, Paul W

    2013-04-01

    Emotional state can modulate the perception of respiratory loads but the range of respiratory load magnitudes affected by emotional state is unknown. We hypothesized that viewing pleasant, neutral and unpleasant affective pictures would modulate the perception of respiratory loads of different load magnitudes. Twenty-four healthy adults participated in the study. Five inspiratory resistive loads of increasing magnitude (5, 10, 15, 20, 45 cm H(2)O/L/s) were repeatedly presented for one inspiration while participants viewed pleasant, neutral and unpleasant affective picture series. Participants rated how difficult it was to breathe against the load immediately after each presentation. Only at the lowest load, magnitude estimation ratings were greater when subjects viewed the unpleasant series compared to the neutral and pleasant series. These results suggest that negative emotional state increases the sense of respiratory effort for single presentations of a low magnitude resistive load but high magnitude loads are not further modulated by emotional state.

  10. High-intensity Statin Treatments in Clinically Stable Patients on Aspirin Monotherapy 12 Months After Drug-eluting Stent Implantation: A Randomized Study.

    PubMed

    Im, Eui; Cho, Yun-Hyeong; Suh, Yongsung; Cho, Deok-Kyu; Her, Ae-Young; Kim, Yong Hoon; Lee, Kyounghoon; Kang, Woong Chol; Yun, Kyeong Ho; Yoo, Sang-Yong; Cheong, Sang-Sig; Shin, Dong-Ho; Ahn, Chul-Min; Kim, Jung-Sun; Kim, Byeong-Keuk; Ko, Young-Guk; Choi, Donghoon; Jang, Yangsoo; Hong, Myeong-Ki

    2017-07-14

    Current guidelines on the treatment of blood cholesterol recommend continuous maintenance of high-intensity statin treatment in drug-eluting stent (DES)-treated patients. However, high-intensity statin treatment is frequently underused in clinical practice after stabilization of DES-treated patients. Currently, the impact of continuous high-intensity statin treatment on the incidence of late adverse events in these patients is unknown. We investigated whether high-intensity statin treatment reduces late adverse events in clinically stable patients on aspirin monotherapy 12 months after DES implantation. Clinically stable patients who underwent DES implantation 12 months previously and received aspirin monotherapy were randomly assigned to receive either high-intensity (40mg atorvastatin, n = 1000) or low-intensity (20mg pravastatin, n = 1000) statin treatment. The primary endpoint was adverse clinical events at 12-month follow-up (a composite of all death, myocardial infarction, revascularization, stent thrombosis, stroke, renal deterioration, intervention for peripheral artery disease, and admission for cardiac events). The primary endpoint at 12-month follow-up occurred in 25 patients (2.5%) receiving high-intensity statin treatment and in 40 patients (4.1%) receiving low-intensity statin treatment (HR, 0.58; 95%CI, 0.36-0.92; P = .018). This difference was mainly driven by a lower rate of cardiac death (0 vs 0.4%, P = .025) and nontarget vessel myocardial infarction (0.1 vs 0.7%, P = .033) in the high-intensity statin treatment group. Among clinically stable DES-treated patients on aspirin monotherapy, high-intensity statin treatment significantly reduced late adverse events compared with low-intensity statin treatment. URL: http://www.clinicaltrials.gov. Unique identifier: NCT01557075. Copyright © 2017 Sociedad Española de Cardiología. Published by Elsevier España, S.L.U. All rights reserved.

  11. Aeshnid dragonfly larvae as bioindicators of methylmercury contamination in aquatic systems impacted by elevated sulfate loading

    USGS Publications Warehouse

    Jeremiason, Jeffrey D.; Reiser, T. K.; Weitz, R. A.; Berndt, M.E.; Aiken, George R.

    2016-01-01

    Methylmercury (MeHg) levels in dragonfly larvae and water were measured over two years in aquatic systems impacted to varying degrees by sulfate releases related to iron mining activity. This study examined the impact of elevated sulfate loads on MeHg concentrations and tested the use of MeHg in dragonfly larvae as an indicator of MeHg levels in a range of aquatic systems including 16 river/stream sites and two lakes. MeHg concentrations in aeshnid dragonfly larvae were positively correlated (R2 = 0.46, p < 0.01) to peak MeHg concentrations in the dissolved phase for the combined years of 2012 and 2013. This relation was strong in 2012 (R2 = 0.85, p < 0.01), but showed no correlation in 2013 (R2 = 0.02, p > 0.05). MeHg in dragonfly larvae were not elevated at the highest sulfate sites, but rather the reverse was generally observed. Record rainfall events in 2012 and above average rainfall in 2013 likely delivered the majority of Hg and MeHg to these systems via interflow and activated groundwater flow through reduced sediments. As a result, the impacts of elevated sulfate releases due to mining activities were not apparent in these systems where little of the sulfate is reduced. Lower bioaccumulation factors for MeHg in aeshnid dragonfly larvae were observed with increasing dissolved organic carbon (DOC) concentrations. This finding is consistent with previous studies showing that MeHg in high DOC systems is less bioavailable; an equilibrium model shows that more MeHg being associated with DOC rather than algae at the base of the food chain readily explains the lower bioaccumulation factors.

  12. Analysis of spinal motion and loads during frontal impacts. Comparison between PMHS and ATD.

    PubMed

    Lopez-Valdes, Francisco J; Lau, Anthony; Lamp, John; Riley, Patrick; Lessley, David J; Damon, Andrew; Kindig, Matthew; Kent, Richard; Balasubramanian, Sriram; Seacrist, Thomas; Maltese, Matthew R; Arbogast, Kristy B; Higuchi, Kazuo; Tanji, Hiro

    2010-01-01

    Quantifying the kinematics of the human spine during a frontal impact is a challenge due to the multi-degree-of-freedom structure of the vertebral column. This papers reports on a series of six frontal impacts sled tests performed on three Post Mortem Human Surrogates (PMHS). Each subject was exposed first to a low-speed, non-injurious frontal impact (9 km/h) and then to a high-speed one (40 km/h). Five additional tests were performed using the Hybrid III 50(th) percentile male ATD for comparison with the PMHS. A 3D motion capture system was used to record the 6-degree-of-freedom motion of body segments (head, T1, T8, L2, L4 and pelvis). The 3D trajectories of individual bony structures in the PMHS were determined using bone-mounted marker arrays, thus avoiding skin-attached markers and their potential measurements artifacts. The PMHS spines showed different behavior between low and high speed. While at low speed the head and upper spinal segments lagged the lower portion of the spine and pelvis in reaching their maximum forward displacement (time for maximum forward head excursion was 254.3±31.9 ms and 140.3±9 ms for the pelvis), these differences were minimal at high speed (127±2.6 ms for the head vs. 116.7±3.5 ms for the pelvis). The ATD did not exhibit this speed-dependant behavior. Furthermore, the ATD's forward displacements were consistently less than those exhibited by the PMHS, regardless of the speed. Neck loads at the atlanto-occipital joint were estimated for the PMHS using inverse dynamics techniques and compared to those measured in the ATD. It was found that the axial and shear forces and the flexion moment at the upper neck of the PMHS were higher than those measured in the ATD.

  13. Aeshnid dragonfly larvae as bioindicators of methylmercury contamination in aquatic systems impacted by elevated sulfate loading.

    PubMed

    Jeremiason, J D; Reiser, T K; Weitz, R A; Berndt, M E; Aiken, G R

    2016-04-01

    Methylmercury (MeHg) levels in dragonfly larvae and water were measured over two years in aquatic systems impacted to varying degrees by sulfate releases related to iron mining activity. This study examined the impact of elevated sulfate loads on MeHg concentrations and tested the use of MeHg in dragonfly larvae as an indicator of MeHg levels in a range of aquatic systems including 16 river/stream sites and two lakes. MeHg concentrations in aeshnid dragonfly larvae were positively correlated (R(2) = 0.46, p < 0.01) to peak MeHg concentrations in the dissolved phase for the combined years of 2012 and 2013. This relation was strong in 2012 (R(2) = 0.85, p < 0.01), but showed no correlation in 2013 (R(2) = 0.02, p > 0.05). MeHg in dragonfly larvae were not elevated at the highest sulfate sites, but rather the reverse was generally observed. Record rainfall events in 2012 and above average rainfall in 2013 likely delivered the majority of Hg and MeHg to these systems via interflow and activated groundwater flow through reduced sediments. As a result, the impacts of elevated sulfate releases due to mining activities were not apparent in these systems where little of the sulfate is reduced. Lower bioaccumulation factors for MeHg in aeshnid dragonfly larvae were observed with increasing dissolved organic carbon (DOC) concentrations. This finding is consistent with previous studies showing that MeHg in high DOC systems is less bioavailable; an equilibrium model shows that more MeHg being associated with DOC rather than algae at the base of the food chain readily explains the lower bioaccumulation factors.

  14. Analysis of spinal motion and loads during frontal impacts. Comparison between PMHS and ATD

    PubMed Central

    Lopez-Valdes, Francisco J.; Lau, Anthony; Lamp, John; Riley, Patrick; Lessley, David J.; Damon, Andrew; Kindig, Matthew; Kent, Richard; Balasubramanian, Sriram; Seacrist, Thomas; Maltese, Matthew R.; Arbogast, Kristy B.; Higuchi, Kazuo; Tanji, Hiro

    2010-01-01

    Quantifying the kinematics of the human spine during a frontal impact is a challenge due to the multi-degree-of-freedom structure of the vertebral column. This papers reports on a series of six frontal impacts sled tests performed on three Post Mortem Human Surrogates (PMHS). Each subject was exposed first to a low-speed, non-injurious frontal impact (9 km/h) and then to a high-speed one (40 km/h). Five additional tests were performed using the Hybrid III 50th percentile male ATD for comparison with the PMHS. A 3D motion capture system was used to record the 6-degree-of-freedom motion of body segments (head, T1, T8, L2, L4 and pelvis). The 3D trajectories of individual bony structures in the PMHS were determined using bone-mounted marker arrays, thus avoiding skin-attached markers and their potential measurements artifacts. The PMHS spines showed different behavior between low and high speed. While at low speed the head and upper spinal segments lagged the lower portion of the spine and pelvis in reaching their maximum forward displacement (time for maximum forward head excursion was 254.3±31.9 ms and 140.3±9 ms for the pelvis), these differences were minimal at high speed (127±2.6 ms for the head vs. 116.7±3.5 ms for the pelvis). The ATD did not exhibit this speed-dependant behavior. Furthermore, the ATD’s forward displacements were consistently less than those exhibited by the PMHS, regardless of the speed. Neck loads at the atlanto-occipital joint were estimated for the PMHS using inverse dynamics techniques and compared to those measured in the ATD. It was found that the axial and shear forces and the flexion moment at the upper neck of the PMHS were higher than those measured in the ATD. PMID:21050592

  15. Neuromuscular And Cardiovascular Adaptations In Response To High Intensity Interval Power Training.

    PubMed

    Romero-Arenas, Salvador; Ruiz, Rubén; Vera, Antonio; Colomer-Poveda, David; Grau, Amelia Guadalupe; Márquez, Gonzalo

    2017-01-11

    The aim of the present study was to determine the efficacy of a high-intensity power training (HIPT) program, and to compare the effects of HIPT to traditional power training (TPT) on the aerobic and power performance. For this purpose, 29 healthy men (23.1±2.7 years) were recruited and randomly distributed into three different groups. One group performed traditional power training (TPT n=10), the second group performed power training organized as a circuit (HIPT; n=10) and the third group served as control (CG; n=9). Training consisted of weight lifting thrice per week for six weeks. TPT subjects performed three to five sets of each exercises with inter-set rest of 90 s, and HIPT subjects executed the training in a short circuit (15 s of rest between exercises). In order to known the effects in aerobic performance, maximal aerobic speed (MAS) was measured. In order to identify the effects on power performance subjects performed a Wingate test, a countermovement jump (CMJ) test and a power-load curve in bench press. The main results showed that after both power training protocols subjects increased significantly (p<0.05) the power production during the Wingate Test, the height and power reached during the CMJ test and the peak power produced during the power-load curve. However, only the HIPT group improved significantly MAS (p<0.05). There were no changes in any variables in CG. Hence, our results suggest that HIPT may be as effective as TPT for improving power performance in young adults. Additionally, only HIPT elicited improvements in MAS.

  16. Effect of set configuration on hemodynamics and cardiac autonomic modulation after high-intensity squat exercise.

    PubMed

    Iglesias-Soler, Eliseo; Boullosa, Daniel A; Carballeira, Eduardo; Sánchez-Otero, Tania; Mayo, Xian; Castro-Gacio, Xabier; Dopico, Xurxo

    2015-07-01

    The aim of this study was to compare the effect of two different high-intensity resistance exercise (RE) set configurations on the following: systolic blood pressure (SBP), rate pressure product (RPP), heart rate (HR) variability (HRV), and HR complexity (HRC). Ten well-trained males performed three parallel squat sets until failure (traditional training; TT) with the four repetitions maximum load (4RM), and a rest of 3 min between sets. Thereafter, participants performed a cluster training session (CT) of equated load but with resting time distributed between each repetition. Dependent variables were recorded before, during, and after RE. Mean SBP (25·7 versus 10·9% percentage increase; P = 0·016) and RPP (112·5 versus 69·9%; P = 0·01) were significantly higher in TT. The decrease in HRV after exercise and the drop of HRC during exercise were similar in CT and TT. Change of standard deviation of normal RR intervals after TT correlated with change in SBP (r = 0·803; P = 0·009) while the change of Sample Entropy during exercise correlated with the increment of RPP during CT (ρ = -0·667; P = 0·05). This study suggests that set configuration influences acute cardiovascular responses during RE. When intensity, volume and work-to-rest ratio are equated, CT is less demanding in terms of SBP and RPP. A greater hemodynamic response during exercise would be associated with a faster parasympathetic recovery. © 2014 Scandinavian Society of Clinical Physiology and Nuclear Medicine. Published by John Wiley & Sons Ltd.

  17. Physical and structural changes in liquid whole egg treated with high-intensity pulsed electric fields.

    PubMed

    Marco-Molés, Raquel; Rojas-Graü, María A; Hernando, Isabel; Pérez-Munuera, Isabel; Soliva-Fortuny, Robert; Martín-Belloso, Olga

    2011-03-01

    Liquid whole egg (LWE) is currently pasteurized through the application of heat; however, this treatment entails deleterious effects against some of the functional and technological properties of the product. In this study, the effect of high-intensity pulsed electric fields (HIPEF) processing (field strength: 19, 32, and 37 kV/cm) was compared to the traditional heat pasteurization (66 °C for 4.5 min). Different physical and structural characteristics of LWE, subjected or not to homogenization, were evaluated and compared, having the untreated LWE as a reference. Thermal treatment caused an increase in the viscosity of LWE, especially in nonhomogenized samples. HIPEF treatments did not modify the original color of LWE, whereas thermally treated samples developed an opaque appearance. LWE treated at 19 and 32 kV/cm exhibited a similar foaming capacity as fresh untreated egg, whereas thermal processing and PEF treatments of 37 kV/cm caused a substantial decrease in the foaming capacity of untreated liquid egg. Regarding the microstructure, the lipoprotein matrix appeared to be less affected by the HIPEF than by heat treatment if compared to the control. In addition, heat pasteurization had a significant impact on both the water-soluble protein content of the LWE samples (19.5% to 23.6% decrease) and the mechanical properties of the egg gels (up to 21.3% and 14.5% increase in hardness and cohesiveness, respectively). On the other hand, these parameters were not substantially affected in the HIPEF-treated samples. Heat-induced gels obtained from HIPEF-treated samples did not exhibit remarkable differences in the water-holding capacity (WHC) with respect to heat-pasteurized samples. The impact of high-intensity pulsed electric fields (HIPEF) processing on technological properties of liquid-whole egg was investigated and compared to that of thermal processing. Heat treatments cause a severe impact on the foaming capacity, the water-soluble protein content, and the

  18. Documenting PyroCb Development on High-Intensity Boreal Fires: Implications for the Arctic Atmosphere

    NASA Astrophysics Data System (ADS)

    Stocks, B. J.; Fromm, M. D.; Servranckx, R.; Lindsey, D.

    2007-12-01

    The recent confirmation that smoke from high-intensity boreal forest fires can reach the Upper Troposphere/Lower Stratosphere (UTLS) through pyroconvection and be transported long distances has raised concern over the wider-scale environmental impact of boreal fire smoke. This concern is further elevated as climate change projections indicate a significant increase in the frequency and severity of boreal forest fires over the next century. Smoke in the UTLS is frequently transported to the Arctic and may have important implications for the radiative energy budget in the polar region. Soot deposition from fires may lead to enhanced melting of sea ice and glaciers, and the chemical impact of fire emissions at high altitudes is largely unknown. This knowledge gap will be addressed during the International Polar Year (IPY), as boreal fire emissions will be tracked and documented in detail through aerial, satellite and ground-based measurements, as a key component of the POLARCAT (Polar Study using Aircraft, Remote Sensing, Surface Measurements and Models, of Climate, Chemistry, Aerosols, and Transport) and ARCTAS (Arctic Research of the Composition of the Troposphere from Aircraft and Satellites) projects to be conducted in 2008. A large fire in the Canadian Northwest Territories burned throughout the month of June 2007, in a remote region where forest fires are not actively suppressed, eventually reaching 90,000 hectares in size. This fire was monitored for blowup one week in advance; it erupted into pyroconvection on June 25, 2007. We present an analysis of this event combining satellite data with ground-based measurements to document the development and impact of this classic pyroCb event. Under extreme fire danger conditions, the fire burned close to 20,000 hectares on that day. Fire behavior was consistent with predictions using the Canadian Fire Behavior Prediction System, with the fire spreading at 2.7 km/hr, consuming 33,000 kg of fuel hourly, generating an

  19. Effects of partial interlaminar bonding on impact resistance and loaded-hole behavior of graphite/epoxy quasi-isotropic laminates

    NASA Technical Reports Server (NTRS)

    Illg, W.

    1986-01-01

    A partial-bonding interlaminar toughening concept was evaluated for resistance to impact and for behavior of a loaded hole. Perforated Mylar sheets were interleaved between all 24 plies of a graphite/epoxy quasi-isotropic lay-up. Specimens were impacted by aluminum spheres while under tensile or compressive loads. Impact-failure thresholds and residual strengths were obtained. Loaded-hole specimens were tested in three configurations that were critical in bearing, shear, or tension. Partial bonding reduced the tensile and compressive strengths of undamaged specimens by about one-third. For impact, partial bonding did not change the threshold for impact failure under tensile preload. However, under compressive preload, partial bonding caused serious degradation of impact resistance. Partial bonding reduced the maximum load-carrying capacity of all three types of loaded-hole specimens. Overall, partial bonding degraded both impact resistance and bearing strength of holes.

  20. Towards Simplified Tools for Analysis of Reinforced Concrete Structures Subjected to Impact and Impulsive Loading: A Preliminary Investigation

    NASA Astrophysics Data System (ADS)

    Trommels, Heather

    The analysis of reinforced concrete structures under blast and impact loads is an area of research that has become increasingly relevant in recent years. Complex hydrocodes are typically used for impact analyses, although single-degree-of-freedom methods have also been developed. There are a number of disadvantages associated with both methods, and the Canadian Nuclear Safety Commission (CNSC) is looking for a tool that can be used in conjunction with hydrocodes to analyze hard and soft missile impacts, with target damage ranging from flexural cracking to perforation. The VecTor programs, a suite of nonlinear finite element programs developed at the University of Toronto for the analysis of reinforced concrete structures, can potentially be developed into such tools. The analytical work done in this study serves to investigate the current impact and impulse loading analysis capabilities in VecTor2 and VecTor3, and to identify areas where work should be focused in the future.

  1. Combined impacts of future climate and land use changes on discharge, nitrogen and phosphorus loads for a Canadian river basin.

    PubMed

    El-Khoury, A; Seidou, O; Lapen, D R; Que, Z; Mohammadian, M; Sunohara, M; Bahram, D

    2015-03-15

    Both climate and land use changes can influence water quality and quantity in different ways. Thus, for predicting future water quality and quantity trends, simulations should ideally account for both projected climate and land use changes. In this paper, land use projections and climate change scenarios were integrated with a hydrological model to estimate the relative impact of climate and land use projections on a suite of water quality and quantity endpoints for a Canadian watershed. Climatic time series representing SRES change scenario A2 were generated by downscaling the outputs of the Canadian Regional Climate Model (version 4.1.1) using a combination of quantile-quantile transformation and nearest neighbor search. The SWAT (Soil and Water Assessment Tool) model was used to simulate streamflow, nitrogen and phosphorus loading under different climate and land use scenarios. Results showed that a) climate change will drive up maximum monthly streamflow, nitrate loads, and organic phosphorus loads, while decreasing organic nitrogen and nitrite loads; and b) land use changes were found to drive the same water quality/quantity variables in the same direction as climate change, except for organic nitrogen loads, for which the effects of the two stressors had a reverse impact on loading. Copyright © 2014 The Authors. Published by Elsevier Ltd.. All rights reserved.

  2. IMPACT OF SIPHONING ACTIVITY AND NATURALLY SUSPENDED PARTICLE LOAD ON MUSSEL KILL by PSEUDOMONAS FLUORESCENS

    SciTech Connect

    Daniel Molloy

    2003-08-04

    Under this USDOE-NETL contract, the bacterium Pseudomonas fluorescens is being developed as a biocontrol agent for zebra mussels. The specific purpose of the contract is to identify biotic and abiotic factors that affect mussel kill. Ingestion of these bacteria by zebra mussels is required to achieve kill, and tests evaluating factors that relate to mussel feeding are contained in this report. Specifically the impact of the following two factors were investigated: (1) Mussel siphoning behavior--In nature, zebra mussels typically have their two shells spread apart and their inhalant siphon tube extended from between their shells for taking food particles into their mantle cavities (Fig. 1). Our tests indicated that there is a direct correlation between mussel siphoning activity and mussel mortality achieved by a bacterial treatment. Therefore, to encourage mussel feeding on bacteria, future pipe treatments within power plants should be carried out using procedures which minimize disturbance to mussel siphoning. 2. Naturally suspended particle loads--Since bacterial cells are lethal only if ingested by mussels, waters containing very high levels of naturally suspended particles might reduce the mortality that can be achieved by a bacterial treatment. If true, this inhibition might occur as a result of particle exclusion, i.e., there could be reduced ingestion of bacterial cells since they represent a reduced percentage of all particles ingested. Our tests indicated that a range of particle concentrations that might naturally exist in a turbid river did not inhibit mussel kill by the bacterial cells, but that an artificially high load of natural particles was capable of causing a reduction in kill. To be conservative, therefore, future pipe treatments should be timed to occur when intake waters have relatively low quantities of naturally suspended particulate matter.

  3. Impact and programmatic implications of routine viral load monitoring in Swaziland.

    PubMed

    Jobanputra, Kiran; Parker, Lucy Anne; Azih, Charles; Okello, Velephi; Maphalala, Gugu; Jouquet, Guillaume; Kerschberger, Bernhard; Mekeidje, Calorine; Cyr, Joanne; Mafikudze, Arnold; Han, Win; Lujan, Johnny; Teck, Roger; Antierens, Annick; van Griensven, Johan; Reid, Tony

    2014-09-01

    To assess the programmatic quality (coverage of testing, counseling, and retesting), cost, and outcomes (viral suppression, treatment decisions) of routine viral load (VL) monitoring in Swaziland. Retrospective cohort study of patients undergoing routine VL monitoring in Swaziland (October 1, 2012 to March 31, 2013). Of 5563 patients eligible for routine VL testing monitoring in the period of study, an estimated 4767 patients (86%) underwent testing that year. Of 288 patients with detectable VL, 210 (73%) underwent enhanced adherence counseling and 202 (70%) had a follow-up VL within 6 months. Testing coverage was slightly lower in children, but coverage of retesting was similar between and age groups and sexes. Of those with a follow-up test, 126 (62%) showed viral suppression. The remaining 78 patients had World Health Organization-defined virologic failure; 41 (53%) were referred by the doctor for more adherence counseling, and 13 (15%) were changed to second-line therapy, equating to an estimated rate of 1.2 switches per 100 patient-years. Twenty-four patients (32%) were transferred out, lost to follow-up, or not reviewed by doctor. The "fully loaded" cost of VL monitoring was $35 per patient-year. Achieving good quality VL monitoring is feasible and affordable in resource-limited settings, although close supervision is needed to ensure good coverage of testing and counseling. The low rate of switch to second-line therapy in patients with World Health Organization-defined virologic failure seems to reflect clinician suspicion of ongoing adherence problems. In our study, the main impact of routine VL monitoring was reinforcing adherence rather than increasing use of second-line therapy.

  4. The Influence of Sorbent Properties and Reaction Conditions on Attrition of Limestone by Impact Loading in Fluidized Beds

    NASA Astrophysics Data System (ADS)

    Scala, Fabrizio; Salatino, Piero

    The extent of attrition associated with impact loading was studied for five different limestones pre-processed in fluidized bed under different reaction conditions. The experimental procedure was based on the measurement of the amount and the particle size distribution of the debris generated upon impact of sorbent samples against a target at velocities between 10 and 45 m/s. The effect of calcination, sulfation and calcination/re-carbonation on impact damage was assessed. Fragmentation by impact loading of the limestones was significant and increased with the impact velocity. Lime samples displayed the largest propensity to undergo impact damage, followed by sulfated, re-carbonated and raw limestones. Fragmentation of the sulfated samples followed a partem typical of the failure of brittle materials. On the other hand, the behavior of lime samples better conformed to a disintegration failure mode, with extensive generation of very fine fragments. Raw limestone and re-carbonated lime samples followed either of the two patterns depending on the sorbent nature. The extent of particle fragmentation increased after multiple impacts, but the incremental amount of fragments generated upon one impact decreased with the number of successive impacts.

  5. The impact of benthic fauna on fluvial bed load transport: Challenges of upscaling laboratory experiments to river and landscape scales.

    NASA Astrophysics Data System (ADS)

    Rice, S. P.

    2012-04-01

    The impact on sediment transport processes and channel morphology of several relatively large, iconic animals including beaver and salmon is increasingly well understood. However, many other aquatic fauna are important zoogeomorphic agents and ecosystem engineers. These somewhat overlooked "Cinderella" species include benthic aquatic insect larvae, freshwater crustaceans and many species of fish. Despite relatively modest individual effects, the ubiquity, abundance and cumulative impact of these organisms makes them a potentially significant agency, with as yet undiscovered and unquantified impacts on channel morphology and sediment fluxes. Their actions (digging, foraging, moving, burrowing), constructions and secretions modify bed sediment characteristics (grain size distribution, interlock, imbrication, protrusion), alter bed topography (thence hydraulic roughness) and contribute to biogenic restraints on grain movement. In turn, they can affect the distribution of surface particle entrainment thresholds and bed shear stresses, with implications for bed load transport. Flume experiments have measured some of these impacts and provided direct observations of the mechanisms involved, but many of the most interesting research questions pertain to the impact of these animals at reach, catchment and even landscape scales: Not least, what is the impact of small aquatic animals on bed load flux and yield? This presentation will consider some of the challenges involved in answering this question; that is, of scaling up experimental understanding of how aquatic animals affect bed load transport processes to river scales. Pertinent themes include: (1) the potential impacts of experimental arrangements on the behaviours and activities that affect hydraulic or geomorphological processes; (2) field coincidence of the spatial and temporal distributions of (a) the animals and their behaviours with (b) the physical conditions (substrates, flows) under which those animals are

  6. High-intensity interval exercise and cerebrovascular health: curiosity, cause, and consequence.

    PubMed

    Lucas, Samuel J E; Cotter, James D; Brassard, Patrice; Bailey, Damian M

    2015-06-01

    Exercise is a uniquely effective and pluripotent medicine against several noncommunicable diseases of westernised lifestyles, including protection against neurodegenerative disorders. High-intensity interval exercise training (HIT) is emerging as an effective alternative to current health-related exercise guidelines. Compared with traditional moderate-intensity continuous exercise training, HIT confers equivalent if not indeed superior metabolic, cardiac, and systemic vascular adaptation. Consequently, HIT is being promoted as a more time-efficient and practical approach to optimize health thereby reducing the burden of disease associated with physical inactivity. However, no studies to date have examined the impact of HIT on the cerebrovasculature and corresponding implications for cognitive function. This review critiques the implications of HIT for cerebrovascular function, with a focus on the mechanisms and translational impact for patient health and well-being. It also introduces similarly novel interventions currently under investigation as alternative means of accelerating exercise-induced cerebrovascular adaptation. We highlight a need for studies of the mechanisms and thereby also the optimal dose-response strategies to guide exercise prescription, and for studies to explore alternative approaches to optimize exercise outcomes in brain-related health and disease prevention. From a clinical perspective, interventions that selectively target the aging brain have the potential to prevent stroke and associated neurovascular diseases.

  7. High-intensity interval exercise and cerebrovascular health: curiosity, cause, and consequence

    PubMed Central

    Lucas, Samuel J E; Cotter, James D; Brassard, Patrice; Bailey, Damian M

    2015-01-01

    Exercise is a uniquely effective and pluripotent medicine against several noncommunicable diseases of westernised lifestyles, including protection against neurodegenerative disorders. High-intensity interval exercise training (HIT) is emerging as an effective alternative to current health-related exercise guidelines. Compared with traditional moderate-intensity continuous exercise training, HIT confers equivalent if not indeed superior metabolic, cardiac, and systemic vascular adaptation. Consequently, HIT is being promoted as a more time-efficient and practical approach to optimize health thereby reducing the burden of disease associated with physical inactivity. However, no studies to date have examined the impact of HIT on the cerebrovasculature and corresponding implications for cognitive function. This review critiques the implications of HIT for cerebrovascular function, with a focus on the mechanisms and translational impact for patient health and well-being. It also introduces similarly novel interventions currently under investigation as alternative means of accelerating exercise-induced cerebrovascular adaptation. We highlight a need for studies of the mechanisms and thereby also the optimal dose-response strategies to guide exercise prescription, and for studies to explore alternative approaches to optimize exercise outcomes in brain-related health and disease prevention. From a clinical perspective, interventions that selectively target the aging brain have the potential to prevent stroke and associated neurovascular diseases. PMID:25833341

  8. Nitrogen critical loads and management alternatives for N-impacted ecosystems in California.

    PubMed

    Fenn, M E; Allen, E B; Weiss, S B; Jovan, S; Geiser, L H; Tonnesen, G S; Johnson, R F; Rao, L E; Gimeno, B S; Yuan, F; Meixner, T; Bytnerowicz, A

    2010-12-01

    Empirical critical loads for N deposition effects and maps showing areas projected to be in exceedance of the critical load (CL) are given for seven major vegetation types in California. Thirty-five percent of the land area for these vegetation types (99,639 km(2)) is estimated to be in excess of the N CL. Low CL values (3-8 kg N ha(-1) yr(-1)) were determined for mixed conifer forests, chaparral and oak woodlands due to highly N-sensitive biota (lichens) and N-poor or low biomass vegetation in the case of coastal sage scrub (CSS), annual grassland, and desert scrub vegetation. At these N deposition critical loads the latter three ecosystem types are at risk of major vegetation type change because N enrichment favors invasion by exotic annual grasses. Fifty-four and forty-four percent of the area for CSS and grasslands are in exceedance of the CL for invasive grasses, while 53 and 41% of the chaparral and oak woodland areas are in exceedance of the CL for impacts on epiphytic lichen communities. Approximately 30% of the desert (based on invasive grasses and increased fire risk) and mixed conifer forest (based on lichen community changes) areas are in exceedance of the CL. These ecosystems are generally located further from emissions sources than many grasslands or CSS areas. By comparison, only 3-15% of the forested and chaparral land areas are estimated to be in exceedance of the NO(3)(-) leaching CL. The CL for incipient N saturation in mixed conifer forest catchments was 17 kg N ha(-1) yr(-1). In 10% of the CL exceedance areas for all seven vegetation types combined, the CL is exceeded by at least 10 kg N ha(-1) yr(-1), and in 27% of the exceedance areas the CL is exceeded by at least 5 kg N ha(-1) yr(-1). Management strategies for mitigating the effects of excess N are based on reducing N emissions and reducing site N capital through approaches such as biomass removal and prescribed fire or control of invasive grasses by mowing, selective herbicides, weeding or

  9. 14 CFR 23.1308 - High-intensity Radiated Fields (HIRF) Protection.

    Code of Federal Regulations, 2010 CFR

    2010-01-01

    ... 14 Aeronautics and Space 1 2010-01-01 2010-01-01 false High-intensity Radiated Fields (HIRF... Equipment General § 23.1308 High-intensity Radiated Fields (HIRF) Protection. (a) Except as provided in... reduce the capability of the airplane or the ability of the flightcrew to respond to an adverse...

  10. Soil hydraulic characteristics of a small southwest Oregon watershed following high-intensity wildfires

    Treesearch

    David S. Parks; Terrance W. Cundy

    1989-01-01

    The Angel Fire of September, 1987 caused extensive damage to second growth forest in the south fork drainage of Cow Creek, 55 km northeast of Grant's Pass, Oregon, USA. The fire was characterized by a high-intensity burn over areas of steep topography. The areal distribution of soil hydraulic properties in a small, tributary watershed following high-intensity...

  11. Effect of Short-Term, High-Intensity Exercise on Anaerobic Threshold in Women.

    ERIC Educational Resources Information Center

    Evans, Blanche W.

    This study investigated the effects of a six-week, high-intensity cycling program on anaerobic threshold (AT) in ten women. Subjects trained four days a week using high-intensity interval-type cycle exercises. Workouts included six 4-minute intervals cycling at 85 percent maximal oxygen uptake (VO sub 2 max), separated by 3-minute intervals of…

  12. Caffeine withdrawal and high-intensity endurance cycling performance.

    PubMed

    Irwin, Christopher; Desbrow, Ben; Ellis, Aleisha; O'Keeffe, Brooke; Grant, Gary; Leveritt, Michael

    2011-03-01

    In this study, we investigated the impact of a controlled 4-day caffeine withdrawal period on the effect of an acute caffeine dose on endurance exercise performance. Twelve well-trained and familiarized male cyclists, who were caffeine consumers (from coffee and a range of other sources), were recruited for the study. A double-blind placebo-controlled cross-over design was employed, involving four experimental trials. Participants abstained from dietary caffeine sources for 4 days before the trials and ingested capsules (one in the morning and one in the afternoon) containing either placebo or caffeine (1.5 mg · kg(-1) body weight · day(-1)). On day 5, capsules containing placebo or caffeine (3 mg · kg(-1) body weight) were ingested 90 min before completing a time trial, equivalent to one hour of cycling at 75% peak sustainable power output. Hence the study was designed to incorporate placebo-placebo, placebo-caffeine, caffeine-placebo, and caffeine-caffeine conditions. Performance time was significantly improved after acute caffeine ingestion by 1:49 ± 1:41 min (3.0%, P = 0.021) following a withdrawal period (placebo-placebo vs. placebo-caffeine), and by 2:07 ± 1:28 min (3.6%, P = 0.002) following the non-withdrawal period (caffeine-placebo vs. caffeine-caffeine). No significant difference was detected between the two acute caffeine trials (placebo-caffeine vs. caffeine-caffeine). Average heart rate throughout exercise was significantly higher following acute caffeine administration compared with placebo. No differences were observed in ratings of perceived exertion between trials. A 3 mg · kg(-1) dose of caffeine significantly improves exercise performance irrespective of whether a 4-day withdrawal period is imposed on habitual caffeine users.

  13. Calculation of reinforced-concrete frame strength under a simultaneous static cross section load and a column lateral impact

    NASA Astrophysics Data System (ADS)

    Belov, Nikolay; Yugov, Nikolay; Kopanitsa, Dmitry; Kopanitsa, Georgy; Yugov, Alexey; Kaparulin, Sergey; Plyaskin, Andrey; Kalichkina, Anna; Ustinov, Artyom

    2016-01-01

    When designing buildings with reinforced concrete that are planned to resist dynamic loads it is necessary to calculate this structural behavior under operational static and emergency impact and blast loads. Calculations of the structures under shock-wave loads can be performed by solving dynamic equations that do not consider static loads. Due to this fact the calculation of reinforced concrete frame under a simultaneous static and dynamic load in full 3d settings becomes a very non trivial and resource consuming problem. This problem can be split into two tasks. The first one is a shock-wave problem that can be solved using software package RANET-3, which allows solving the problem using finite elements method adapted for dynamic task. This method calculates strain-stress state of the material and its dynamic destruction, which is considered as growth and consolidation of micro defects under loading. On the second step the results of the first step are taken as input parameters for quasi static calculation of simultaneous static and dynamic load using finite elements method in AMP Civil Engineering-11.

  14. Calculation of reinforced-concrete frame strength under a simultaneous static cross section load and a column lateral impact

    SciTech Connect

    Belov, Nikolay Kopanitsa, Dmitry Yugov, Alexey Kaparulin, Sergey Plyaskin, Andrey Kalichkina, Anna Ustinov, Artyom; Yugov, Nikolay; Kopanitsa, Georgy

    2016-01-15

    When designing buildings with reinforced concrete that are planned to resist dynamic loads it is necessary to calculate this structural behavior under operational static and emergency impact and blast loads. Calculations of the structures under shock-wave loads can be performed by solving dynamic equations that do not consider static loads. Due to this fact the calculation of reinforced concrete frame under a simultaneous static and dynamic load in full 3d settings becomes a very non trivial and resource consuming problem. This problem can be split into two tasks. The first one is a shock-wave problem that can be solved using software package RANET-3, which allows solving the problem using finite elements method adapted for dynamic task. This method calculates strain-stress state of the material and its dynamic destruction, which is considered as growth and consolidation of micro defects under loading. On the second step the results of the first step are taken as input parameters for quasi static calculation of simultaneous static and dynamic load using finite elements method in AMP Civil Engineering-11.

  15. Impacts of Varying Penetration of Distributed Resources with & without Volt/Var Control: Case Study of Varying Load Types

    SciTech Connect

    Rizy, D Tom; Li, Huijuan; Li, Fangxing; Xu, Yan; Adhikari, Sarina; Irminger, Philip

    2011-01-01

    This paper provides a follow-up to an earlier one on impacts of distributed energy resources (DR) on distribution feeders. As DR penetration level on the feeder increases, there can be impacts to distribution system/feeder capacity, line losses, and voltage regulation. These can vary as the penetration level reaches the capacity of the distribution feeder/system or loading. The question is how high of a DR level can be accommodated without any major changes to system operation, system design and protection. Our objective for this work was to address the question of how the DR impacts vary in regards to both DR voltage regulation capability and load mix. A dynamic analysis was used to focus on the impacts of DR with and without volt/var control with different load composition on the distribution feeder. The study considered an example 10MVA distribution feeder in which two inverter-based DRs were used to provide voltage regulation. The results due to DR without voltage regulation capability are compared with DR capable of providing local (at its bus) voltage regulation. The analysis was repeated for four different feeder load compositions consisting of (1) constant power, (2) constant impedance, (3) constant current and (4) ZIP (equal combination of previous three).

  16. Constitutive modeling of rate-dependent stress-strain behavior of human liver in blunt impact loading.

    PubMed

    Sparks, Jessica L; Dupaix, Rebecca B

    2008-11-01

    An understanding of the mechanical deformation behavior of the liver under high strain rate loading conditions could aid in the development of vehicle safety measures to reduce the occurrence of blunt liver injury. The purpose of this study was to develop a constitutive model of the stress-strain behavior of the human liver in blunt impact loading. Experimental stress and strain data was obtained from impact tests of 12 unembalmed human livers using a drop tower technique. A constitutive model previously developed for finite strain behavior of amorphous polymers was adapted to model the observed liver behavior. The elements of the model include a nonlinear spring in parallel with a linear spring and nonlinear dashpot. The model captures three features of liver stress-strain behavior in impact loading: (1) relatively stiff initial modulus, (2) rate-dependent yield or rollover to viscous "flow" behavior, and (3) strain hardening at large strains. Six material properties were used to define the constitutive model. This study represents a novel application of polymer mechanics concepts to understand the rate-dependent large strain behavior of human liver tissue under high strain rate loading. Applications of this research include finite element simulations of injury-producing liver or abdominal impact events.

  17. Climate change impacts on forest soil critical acid loads and exceedances at a national scale

    Treesearch

    Steven G. McNulty; Erika C. Cohen; Jennifer A. Moore Myers

    2013-01-01

    Federal agencies are currently developing guidelines for forest soil critical acid loads across the United States. A critical acid load is defined as the amount of acid deposition (usually expressed on an annual basis) that an ecosystem can absorb. Traditionally, an ecosystem is considered to be at risk for health impairment when the critical acid load exceeds a level...

  18. Composite components under impact load and effects of defects on the loading capacity. [Alpha Jet tail assembly

    NASA Technical Reports Server (NTRS)

    Aoki, R.; Wurzel, D.

    1979-01-01

    Investigations were carried out on a horizontal tail assembly made of carbon fiber reinforced plastic for the Alpha Jet. The possibility of obtaining a leading edge nose design lighter but not more expensive than a metal version was studied. An important consideration was sufficient resistance of the leading edge against impact of stones and hailstones combined with high degree of stiffness. The improvement of energy reception characteristics of the materials through suitable laminate design was considered. Since certain defects occur in structural components, the effects of such defects on the characteristics of the parts were also studied.

  19. The different effects of high intensity interval training and moderate intensity interval training for weightlessness countermeasures

    NASA Astrophysics Data System (ADS)

    Wang, Lin-Jie; Cheng, Tan; Zhi-Li, Li; Hui-juan, Wang; Wen-juan, Chen; Jianfeng, Zhang; Desheng, Wang; Dongbin, Niu; Qi, Zhao; Chengjia, Yang; Yanqing, Wang

    High intensity interval training (HIIT) has been demonstrated to improve performance in a relatively short training period. But the difference between high intensity interval training and moderate intensity interval training (MIIT) in simulated weightlessness still has not been well studied. This study sought to characterize the difference between 6 weeks high intensity interval training and moderate intensity interval training under reduced weight (RW) gait training device and zero-gravity locomotion system (ZLS). Twenty-three subjects (14M/4F, 32.5±4.5 years) volunteered to participate. They were divided into three groups, that were MITT (alternating 2 min at 40% VO _{2} peak and 2 min at 60% VO _{2} peak for 30min, five days per week) RW group (n=8), HITT (alternating 2 min at 40% VO _{2} peak and 2 min at 90% VO _{2} peak for 30min, three days per week) RW group (n=8) and HITT ZLS group (n=7). The Z-axis load used in RW group was 80% body weight (BW) and in ZLS was 100% BW. Cardiopulmonary function was measured before, after 4-week training and after 6-week training. Isokinetic knee extension-flexion test at 60(°) deg/s and 180(°) deg/s were performed before and after the 6-week training, and isometric knee extension-flexion test at 180(°) deg/s was also examined at the same time. It was found that the VO _{2} peaks, metabolic equivalent (MET), Speedmax and respiratory exchange ratio (RER) were significantly increased after 4 and 6-week training in all three groups and no significant group difference were detected. The peak torque at 60(°) deg/s for right knee flexion were significantly increased after 6 week-training in all three groups, and only in HITT RW group the total power at 60(°) deg/s for right knee flexion enhanced. The total power and average power at 60(°) deg/s for right knee extension decreased significantly after 6-week training in all three groups. The peak torque at 60(°) deg/s for right knee extension in MIIT RW group was

  20. Immediate and long term effects of endurance and high intensity interval exercise on linear and nonlinear heart rate variability.

    PubMed

    Perkins, Steven E; Jelinek, Herbert F; Al-Aubaidy, Hayder A; de Jong, Berverlie

    2017-03-01

    Recovery of cardiac autonomic modulation following exercise can be measured using heart rate variability. The objective of this study was to investigate and compare recovery of autonomic cardiac regulation over three days following a single session of high intensity interval training compared to endurance training. Nine untrained students completed two exercise protocols in a one-way crossover design. The endurance protocol consisted of 45min of moderate intensity cycling, and the high intensity interval protocol of six 30s sets of high intensity cycling. Cardiac autonomic activity recovery was measured over three days post-exercise for two hours immediately following each exercise session and each morning thereafter using linear and nonlinear heart rate variability analysis. Both linear and nonlinear measures were significantly decreased immediately following exercise indicating loss of vagal activity. Root mean sum of squared differences (p=0.031) and high frequency (p=0.031) were suppressed following the interval exercise only. The long term correlation of the heart rate applying detrended fluctuation analysis was decreased immediately following endurance training (p=0.039) and trended to increase immediately following the interval protocol (p=0.156). Sample entropy was decreased immediately following both the endurance (p=0.023) and interval (p=0.031) protocols. No exercise effects were noted from 24h post exercise onwards. High intensity interval training had a greater impact on neurocardiac activity than moderate intensity endurance training as indicated by both linear and nonlinear heart rate variability measures. Copyright © 2016 Sports Medicine Australia. Published by Elsevier Ltd. All rights reserved.

  1. Characterization of Tissue Response to Impact Loads Delivered Using a Hand-Held Instrument for Studying Articular Cartilage Injury

    PubMed Central

    Bonnevie, Edward D.; Delco, Michelle L.; Fortier, Lisa A.; Alexander, Peter G.; Tuan, Rocky S.

    2015-01-01

    Objective: The objective of this study was to fully characterize the mechanics of an in vivo impactor and correlate the mechanics with superficial cracking of articular surfaces. Design: A spring-loaded impactor was used to apply energy-controlled impacts to the articular surfaces of neonatal bovine cartilage. The simultaneous use of a load cell and displacement sensor provided measurements of stress, stress rate, strain, strain rate, and strain energy density. Application of India ink after impact was used to correlate the mechanical inputs during impact with the resulting severity of tissue damage. Additionally, a signal processing method to deconvolve inertial stresses from impact stresses was developed and validated. Results: Impact models fit the data well (root mean square error average ~0.09) and provided a fully characterized impact. Correlation analysis between mechanical inputs and degree of superficial cracking made visible through India ink application provided significant positive correlations for stress and stress rate with degree of surface cracking (R2 = 0.7398 and R2 = 0.5262, respectively). Ranges of impact parameters were 7 to 21 MPa, 6 to 40 GPa/s, 0.16 to 0.38, 87 to 236 s−1, and 0.3 to 1.1 MJ/m3 for stress, stress rate, strain, strain rate, and strain energy density, respectively. Thresholds for damage for all inputs were determined at 13 MPa, 15 GPa/s, 0.23, 160 s−1, and 0.59 MJ/m3 for this system. Conclusions: This study provided the mechanical basis for use of a portable, sterilizable, and maneuverable impacting device. Use of this device enables controlled impact loads in vitro or in vivo to connect mechanistic studies with long-term monitoring of disease progression. PMID:26425260

  2. Finite element modeling of laminated composite plates with locally delaminated interface subjected to impact loading.

    PubMed

    Abo Sabah, Saddam Hussein; Kueh, Ahmad Beng Hong

    2014-01-01

    This paper investigates the effects of localized interface progressive delamination on the behavior of two-layer laminated composite plates when subjected to low velocity impact loading for various fiber orientations. By means of finite element approach, the laminae stiffnesses are constructed independently from their interface, where a well-defined virtually zero-thickness interface element is discreetly adopted for delamination simulation. The present model has the advantage of simulating a localized interfacial condition at arbitrary locations, for various degeneration areas and intensities, under the influence of numerous boundary conditions since the interfacial description is expressed discretely. In comparison, the model shows good agreement with existing results from the literature when modeled in a perfectly bonded state. It is found that as the local delamination area increases, so does the magnitude of the maximum displacement history. Also, as top and bottom fiber orientations deviation increases, both central deflection and energy absorption increase although the relative maximum displacement correspondingly decreases when in contrast to the laminates perfectly bonded state.

  3. Insight into the impact of ZnO nanoparticles on aerobic granular sludge under shock loading.

    PubMed

    He, Qiulai; Yuan, Zhe; Zhang, Jing; Zhang, Shilu; Zhang, Wei; Zou, Zhuocheng; Wang, Hongyu

    2017-04-01

    The increasing use of zinc oxide nanoparticles (ZnO NPs) has raised concerns about the environmental threats to the wastewater treatment systems. Shock loading of 10, 50 and 100 mg/L ZnO NPs was conducted to evaluate impacts on reactor performance, microbial activities and extracellular polymeric substances (EPS) in parent aerobic/oxic/anoxic (A/O/A) granular sequencing batch reactors (SBRs). The results showed that ZnO NPs caused inhibition to nitrogen transformations due to acute toxicity to nitrification and denitrification. However, phosphorus removal remained unaffected by the exposure to ZnO NPs. Besides, ZnO NPs significantly enhanced the oxygen respiration rate and caused acute toxicity to ammonia oxidizing rate (10.40-35.21%), phosphorus release rate (37.79-19.80%), aerobic phosphorus uptake rate (36.95-20.69%) and total phosphorus uptake rate (32.77-16.91%) of aerobic granules. ZnO NPs stimulated the secretion of