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Sample records for ground reaction force

  1. Comparison of ground reaction force during different angle of squatting

    OpenAIRE

    Dali, Sharikh; Justine, Maria; Ahmad, Hamid; Othman, Zainal

    2013-01-01

    Squatting is a form of closed kinetic chain movement which commonly being employed in exercise training. However, little is known regarding the amount of force being imposed on the knee at different angles of squat. Thus, the purpose of this study was to compare the vertical ground reaction force (VGRF) at different angles of squatting among the military personnel. Thirty-seven subjects (age=27.1±2.77 years old) participated in this cross-sectional comparative study. The peak of VGRF was ide...

  2. Ground reaction forces during level ground walking with body weight unloading

    Scientific Electronic Library Online (English)

    Ana M. F., Barela; Paulo B. de, Freitas; Melissa L., Celestino; Marcela R., Camargo; José A., Barela.

    2014-12-01

    Full Text Available Background: Partial body weight support (BWS) systems have been broadly used with treadmills as a strategy for gait training of individuals with gait impairments. Considering that we usually walk on level ground and that BWS is achieved by altering the load on the plantar surface of the foot, it w [...] ould be important to investigate some ground reaction force (GRF) parameters in healthy individuals walking on level ground with BWS to better implement rehabilitation protocols for individuals with gait impairments. Objective: To describe the effects of body weight unloading on GRF parameters as healthy young adults walked with BWS on level ground. Method: Eighteen healthy young adults (27±4 years old) walked on a walkway, with two force plates embedded in the middle of it, wearing a harness connected to a BWS system, with 0%, 15%, and 30% BWS. Vertical and horizontal peaks and vertical valley of GRF, weight acceptance and push-off rates, and impulse were calculated and compared across the three experimental conditions. Results: Overall, participants walked more slowly with the BWS system on level ground compared to their normal walking speed. As body weight unloading increased, the magnitude of the GRF forces decreased. Conversely, weight acceptance rate was similar among conditions. Conclusions: Different amounts of body weight unloading promote different outputs of GRF parameters, even with the same mean walk speed. The only parameter that was similar among the three experimental conditions was the weight acceptance rate.

  3. Comparison of vertical ground reaction forces during overground and treadmill running. A validation study

    Directory of Open Access Journals (Sweden)

    Kluitenberg Bas

    2012-11-01

    Full Text Available Abstract Background One major drawback in measuring ground-reaction forces during running is that it is time consuming to get representative ground-reaction force (GRF values with a traditional force platform. An instrumented force measuring treadmill can overcome the shortcomings inherent to overground testing. The purpose of the current study was to determine the validity of an instrumented force measuring treadmill for measuring vertical ground-reaction force parameters during running. Methods Vertical ground-reaction forces of experienced runners (12 male, 12 female were obtained during overground and treadmill running at slow, preferred and fast self-selected running speeds. For each runner, 7 mean vertical ground-reaction force parameters of the right leg were calculated based on five successful overground steps and 30 seconds of treadmill running data. Intraclass correlations (ICC(3,1 and ratio limits of agreement (RLOA were used for further analysis. Results Qualitatively, the overground and treadmill ground-reaction force curves for heelstrike runners and non-heelstrike runners were very similar. Quantitatively, the time-related parameters and active peak showed excellent agreement (ICCs between 0.76 and 0.95, RLOA between 5.7% and 15.5%. Impact peak showed modest agreement (ICCs between 0.71 and 0.76, RLOA between 19.9% and 28.8%. The maximal and average loading-rate showed modest to excellent ICCs (between 0.70 and 0.89, but RLOA were higher (between 34.3% and 45.4%. Conclusions The results of this study demonstrated that the treadmill is a moderate to highly valid tool for the assessment of vertical ground-reaction forces during running for runners who showed a consistent landing strategy during overground and treadmill running. The high stride-to-stride variance during both overground and treadmill running demonstrates the importance of measuring sufficient steps for representative ground-reaction force values. Therefore, an instrumented treadmill seems to be suitable for measuring representative vertical ground-reaction forces during running.

  4. BILATERAL GROUND REACTION FORCES AND JOINT MOMENTS FOR LATERAL SIDESTEPPING AND CROSSOVER STEPPING TASKS

    Directory of Open Access Journals (Sweden)

    William I. Sellers

    2009-03-01

    Full Text Available Racquet sports have high levels of joint injuries suggesting the joint loads during play may be excessive. Sports such as badminton employ lateral sidestepping (SS and crossover stepping (XS movements which so far have not been described in terms of biomechanics. This study examined bilateral ground reaction forces and three dimensional joint kinetics for both these gaits in order to determine the demands of the movements on the leading and trailing limb and predict the contribution of these movements to the occurrence of overuse injury of the lower limbs. A force platform and motion-analysis system were used to record ground reaction forces and track marker trajectories of 9 experienced male badminton players performing lateral SS, XS and forward running tasks at a controlled speed of 3 m·s-1 using their normal technique. Ground reaction force and kinetic data for the hip, knee and ankle were analyzed, averaged across the group and the biomechanical variables compared. In all cases the ground reaction forces and joint moments were less than those experienced during moderate running suggesting that in normal play SS and XS gaits do not lead to high forces that could contribute to increased injury risk. Ground reaction forces during SS and XS do not appear to contribute to the development of overuse injury. The distinct roles of the leading and trailing limb, acting as a generator of vertical force and shock absorber respectively, during the SS and XS may however contribute to the development of muscular imbalances which may ultimately contribute to the development of overuse injury. However it is still possible that faulty use of these gaits might lead to high loads and this should be the subject of future work

  5. Characteristics of temporal fluctuation of the vertical ground reaction force during quiet stance in Parkinson's disease.

    Science.gov (United States)

    Minamisawa, Tadayoshi; Sawahata, Hirohito; Takakura, Kei; Yamaguchi, Takashi

    2012-02-01

    Stance instability is seen in late stage Parkinson's disease (PD). Stabilometer-based center-of-pressure (COP) evaluation is an easy, routine method for measuring postural control ability. Most of the stabilometer- and force plate-based studies on upright postural control have discussed horizontal COP component control. Previous studies on vertical component control have been few, and no fractal analysis-based study on the component has been reported. We aimed to show the influence of neurological changes and aging on the vertical component and the difference in fluctuation pattern behavior in healthy young and elderly subjects as well as Parkinsonian patients. Detrended fluctuation analysis was used to study characteristics of fluctuation of vertical ground reaction force. In the three groups, all scaling exponents (?, ?1, ?2), which are time-correlated data of vertical ground reaction force, had a value >0 and <0.5 (0ground reaction force between Parkinsonian patients and the other groups, suggesting that a neurological influence with PD may be markedly reflected in the vertical ground reaction force. PMID:22019384

  6. Ground reaction force profiles after partial and pancarpal arthrodesis in dogs

    OpenAIRE

    Andreoni, A.; U. Rytz; Vannini, R; Voss, K.

    2010-01-01

    OBJECTIVES: To evaluate and compare long-term functional outcome after partial carpal arthrodesis and pancarpal arthrodesis in dogs using kinetic gait analysis. METHODS: Fourteen dogs with 19 partial carpal or pancarpal arthrodeses were retrospectively examined and underwent force-plate gait analysis. Mean times since surgery were 29.4 and 24.4 months for pancarpal and partial carpal arthrodesis respectively. Vertical and braking-propulsive ground reaction force profiles were compared between...

  7. Analysis of kinematic data and determination of ground reaction force of foot in slow squat

    Science.gov (United States)

    Zhang, Xu-Shu; Guo, Yuan; An, Mei-Wen; Chen, Wei-Yi

    2013-02-01

    In the present paper, the ground reaction force (GRF) acting on foot in slow squat was determined through a force measuring system, and at the same time, the kinematic data of human squat were obtained by analyzing the photographed image sequences. According to the height and body weight, six healthy volunteers were selected, three men in one group and the other three women in another group, and the fundamental parameters of subjects were recorded, including body weight, height and age, etc. Based on the anatomy characteristics, some markers were placed on the right side of joints. While the subject squatted at slow speed on the force platform, the ground reaction forces on the forefoot and heel for each foot were obtained through calibrated force platform. The analysis results show that the reaction force on heel is greater than that on forefoot, and double feet have nearly constant force. Moreover, from processing and analyzing the synchronously photographed image sequences in squat, the kinematic data of human squat were acquired, including mainly the curves of angle, angular velocity and angular acceleration varied with time for knee, hip and ankle joints in a sagittal plane. The obtained results can offer instructive reference for photographing and analyzing the movements of human bodies, diagnosing some diseases, and establishing in the future appropriate mathematical models for the human motion.

  8. Lower limb ice application alters ground reaction force during gait initiation

    Scientific Electronic Library Online (English)

    Thiago B., Muniz; Renato, Moraes; Rinaldo R. J., Guirro.

    2015-04-01

    Full Text Available BACKGROUND: Cryotherapy is a widely used technique in physical therapy clinics and sports. However, the effects of cryotherapy on dynamic neuromuscular control are incompletely explained. OBJECTIVES: To evaluate the effects of cryotherapy applied to the calf, ankle and sole of the foot in healthy y [...] oung adults on ground reaction forces during gait initiation. METHOD: This study evaluated the gait initiation forces, maximum propulsion, braking forces and impulses of 21 women volunteers through a force platform, which provided maximum and minimum ground reaction force values. To assess the effects of cooling, the task - gait initiation - was performed before ice application, immediately after and 30 minutes after removal of the ice pack. Ice was randomly applied on separate days to the calf, ankle and sole of the foot of the participants. RESULTS: It was demonstrated that ice application for 30 minutes to the sole of the foot and calf resulted in significant changes in the vertical force variables, which returned to their pre-application values 30 minutes after the removal of the ice pack. Ice application to the ankle only reduced propulsion impulse. CONCLUSIONS: These results suggest that although caution is necessary when performing activities that require good gait control, the application of ice to the ankle, sole of the foot or calf in 30-minute intervals may be safe even preceding such activities.

  9. Ground Reaction Forces and Loading Rates Associated with Parkour and Traditional Drop Landing Techniques

    OpenAIRE

    Puddle, Damien L.; Maulder, Peter S.

    2013-01-01

    Due to the relative infancy of Parkour there is currently a lack of empirical evidence on which to base specific technique instruction upon. The purpose of this study was to compare the ground reaction forces and loading rates involved in two Parkour landing techniques encouraged by local Parkour instructors and a traditional landing technique recommended in the literature. Ten male participants performed three different drop landing techniques (Parkour precision, Parkour roll, and traditiona...

  10. Bilateral ground reaction forces and joint moments for lateral sidestepping and crossover stepping tasks

    OpenAIRE

    William I. Sellers; Gregor Kuntze; Neil J. Mansfield

    2009-01-01

    Racquet sports have high levels of joint injuries suggesting the joint loads during play may be excessive. Sports such as badminton employ lateral sidestepping (SS) and crossover stepping (XS) movements which so far have not been described in terms of biomechanics. This study examined bilateral ground reaction forces and three dimensional joint kinetics for both these gaits in order to determine the demands of the movements on the leading and trailing limb and predict the contribution of thes...

  11. Foot speed, foot-strike and footwear: linking gait mechanics and running ground reaction forces.

    Science.gov (United States)

    Clark, Kenneth P; Ryan, Laurence J; Weyand, Peter G

    2014-06-15

    Running performance, energy requirements and musculoskeletal stresses are directly related to the action-reaction forces between the limb and the ground. For human runners, the force-time patterns from individual footfalls can vary considerably across speed, foot-strike and footwear conditions. Here, we used four human footfalls with distinctly different vertical force-time waveform patterns to evaluate whether a basic mechanical model might explain all of them. Our model partitions the body's total mass (1.0 Mb) into two invariant mass fractions (lower limb=0.08, remaining body mass=0.92) and allows the instantaneous collisional velocities of the former to vary. The best fits achieved (R(2) range=0.95-0.98, mean=0.97 ± 0.01) indicate that the model is capable of accounting for nearly all of the variability observed in the four waveform types tested: barefoot jog, rear-foot strike run, fore-foot strike run and fore-foot strike sprint. We conclude that different running ground reaction force-time patterns may have the same mechanical basis. PMID:24737756

  12. Three-dimensional kinematics and ground reaction forces during the instep and outstep soccer kicks in pubertal players

    OpenAIRE

    Katis Athanasios; ?????, ?????????; Kellis, Eleftherios; ??????, ??????????

    2010-01-01

    The purpose of the present study was to compare the three-dimensional kinematics of the lower extremities and ground reaction forces between the instep kick and the kick with the outside area of the foot (outstep kick) in pubertal soccer players. Ten pubertal soccer players performed consecutive kicking trials in random order after a two-step angled approach with the instep and the outstep portion of the foot. Three-dimensional data and ground reaction forces were measured during kicking. Pai...

  13. Ground reaction forces and loading rates associated with parkour and traditional drop landing techniques.

    Science.gov (United States)

    Puddle, Damien L; Maulder, Peter S

    2013-01-01

    Due to the relative infancy of Parkour there is currently a lack of empirical evidence on which to base specific technique instruction upon. The purpose of this study was to compare the ground reaction forces and loading rates involved in two Parkour landing techniques encouraged by local Parkour instructors and a traditional landing technique recommended in the literature. Ten male participants performed three different drop landing techniques (Parkour precision, Parkour roll, and traditional) onto a force plate. Compared to the traditional technique the Parkour precision technique demonstrated significantly less maximal vertical landing force (38%, p Parkour roll technique compared to the traditional technique. It is unclear whether or not the Parkour precision technique produced lower landing forces and loading rates than the Parkour roll technique as no significant differences were found. The landing techniques encouraged by local Parkour instructors such as the precision and roll appear to be more appropriate for Parkour practitioners to perform than a traditional landing technique due to the lower landing forces and loading rates experienced. Key pointsParkour precision and Parkour roll landings were found to be safer than a traditional landing technique, resulting in lower maximal vertical forces, slower times to maximal vertical force and ultimately lesser loading rates.Parkour roll may be more appropriate (safer) to utilize than the Parkour precision during Parkour landing scenarios.The Parkour landing techniques investigated n this study may be beneficial for landing by non-Parkour practitioners in everyday life. PMID:24149735

  14. Ground reaction forces and lower-limb joint kinetics of turning gait in typically developing children.

    Science.gov (United States)

    Dixon, Philippe C; Stebbins, Julie; Theologis, Tim; Zavatsky, Amy B

    2014-11-28

    Turning is a common locomotor task essential to daily activity; however, very little is known about the forces and moments responsible for the kinematic adaptations occurring relative to straight-line gait in typically developing children. Thus, the aims of this study were to analyse ground reaction forces (GRFs), ground reaction free vertical torque (TZ), and the lower-limb joint kinetics of 90° outside (step) and inside (spin) limb turns. Step, spin, and straight walking trials from fifty-four typically developing children were analysed. All children were fit with the Plug-in Gait and Oxford Foot Model marker sets while walking over force plates embedded in the walkway. Net internal joint moments and power were computed via a standard inverse dynamics approach. All dependent variables were statistically analysed over the entire curves using the mean difference 95% bootstrap confidence band approach. GRFs were directed medially for step turns and laterally for spin turns during the turning phase. Directions were reversed and magnitudes decreased during the approach phase. Step turns showed reduced ankle power generation, while spin turns showed large TZ. Both strategies required large knee and hip coronal and transverse plane moments during swing. These kinetic differences highlight adaptations required to maintain stability and reorient the body towards the new walking direction during turning. From a clinical perspective, turning gait may better reveal weaknesses and motor control deficits than straight walking in pathological populations, such as children with cerebral palsy, and could potentially be implemented in standard gait analysis sessions. PMID:25311452

  15. Ground Reaction Force Estimates from ActiGraph GT3X+ Hip Accelerations

    OpenAIRE

    Neugebauer, Jennifer M.; Collins, Kelsey H.; Hawkins, David A.

    2014-01-01

    Simple methods to quantify ground reaction forces (GRFs) outside a laboratory setting are needed to understand daily loading sustained by the body. Here, we present methods to estimate peak vertical GRF (pGRFvert) and peak braking GRF (pGRFbrake) in adults using raw hip activity monitor (AM) acceleration data. The purpose of this study was to develop a statistically based model to estimate pGRFvert and pGRFbrake during walking and running from ActiGraph GT3X+ AM acceleration data. 19 males an...

  16. Isokinetic analysis of ankle and ground reaction forces in runners and triathletes

    Scientific Electronic Library Online (English)

    Natália Mariana Silva, Luna; Angelica Castilho, Alonso; Guilherme Carlos, Brech; Luis, Mochizuki; Eduardo Yoshio, Nakano; Júlia Maria D' Andrea, Greve.

    1023-10-01

    Full Text Available OBJECTIVE: To analyze and compare the vertical component of ground reaction forces and isokinetic muscle parameters for plantar flexion and dorsiflexion of the ankle between long-distance runners, triathletes, and nonathletes. METHODS: Seventy-five males with a mean age of 30.26 (±6.5) years were di [...] vided into three groups: a triathlete group (n=26), a long-distance runner group (n = 23), and a non-athlete control group. The kinetic parameters were measured during running using a force platform, and the isokinetic parameters were measured using an isokinetic dynamometer. RESULTS: The non-athlete control group and the triathlete group exhibited smaller vertical forces, a greater ground contact time, and a greater application of force during maximum vertical acceleration than the long-distance runner group. The total work (180º/s) was greater in eccentric dorsiflexion and concentric plantar flexion for the non-athlete control group and the triathlete group than the long-distance runner group. The peak torque (60º/s) was greater in eccentric plantar flexion and concentric dorsiflexion for the control group than the athlete groups. CONCLUSIONS: The athlete groups exhibited less muscle strength and resistance than the control group, and the triathletes exhibited less impact and better endurance performance than the runners.

  17. GROUND REACTION FORCES AND LOADING RATES ASSOCIATED WITH PARKOUR AND TRADITIONAL DROP LANDING TECHNIQUES

    Directory of Open Access Journals (Sweden)

    Damien L. Puddle

    2013-03-01

    Full Text Available Due to the relative infancy of Parkour there is currently a lack of empirical evidence on which to base specific technique instruction upon. The purpose of this study was to compare the ground reaction forces and loading rates involved in two Parkour landing techniques encouraged by local Parkour instructors and a traditional landing technique recommended in the literature. Ten male participants performed three different drop landing techniques (Parkour precision, Parkour roll, and traditional onto a force plate. Compared to the traditional technique the Parkour precision technique demonstrated significantly less maximal vertical landing force (38%, p < 0.01, ES = 1.76 and landing loading rate (54%, p < 0.01, ES = 1.22. Similarly, less maximal vertical landing force (43%, p < 0.01, ES = 2.04 and landing loading rate (63%, p < 0.01, ES = 1.54 were observed in the Parkour roll technique compared to the traditional technique. It is unclear whether or not the Parkour precision technique produced lower landing forces and loading rates than the Parkour roll technique as no significant differences were found. The landing techniques encouraged by local Parkour instructors such as the precision and roll appear to be more appropriate for Parkour practitioners to perform than a traditional landing technique due to the lower landing forces and loading rates experienced

  18. GROUND REACTION FORCE DIFFERENCES BETWEEN RUNNING SHOES, RACING FLATS, AND DISTANCE SPIKES IN RUNNERS

    Directory of Open Access Journals (Sweden)

    Suzanna Logan

    2010-03-01

    Full Text Available Various shoes are worn by distance runners throughout a training season. This study measured the differences in ground reaction forces between running shoes, racing flats, and distance spikes in order to provide information about the potential effects of footwear on injury risk in highly competitive runners. Ten male and ten female intercollegiate distance runners ran across a force plate at 6.7 m·s-1 (for males and 5.7 m·s-1 (for females in each of the three types of shoes. To control for differences in foot strike, only subjects who exhibited a heel strike were included in the data analysis. Two repeated-measures ANOVAs with Tukey's post-hoc tests (p < 0.05 were used to detect differences in shoe types among males and females. For the males, loading rate, peak vertical impact force and peak braking forces were significantly greater in flats and spikes compared to running shoes. Vertical stiffness in spikes was also significantly greater than in running shoes. Females had significantly shorter stance times and greater maximum propulsion forces in racing flats compared to running shoes. Changing footwear between the shoes used in this study alters the loads placed on the body. Care should be taken as athletes enter different phases of training where different footwear is required. Injury risk may be increased since the body may not be accustomed to the differences in force, stance time, and vertical stiffness

  19. Assessment of changes in gait parameters and vertical ground reaction forces after total hip arthroplasty

    Directory of Open Access Journals (Sweden)

    Bhargava P

    2007-01-01

    Full Text Available The principal objectives of arthroplasty are relief of pain and enhancement of range of motion. Currently, postoperative pain and functional capacity are assessed largely on the basis of subjective evaluation scores. Because of the lack of control inherent in this method it is often difficult to interpret data presented by different observers in the critical evaluation of surgical method, new components and modes of rehabilitation. Gait analysis is a rapid, simple and reliable method to assess functional outcome. This study was undertaken in an effort to evaluate the gait characteristics of patients who underwent arthroplasty, using an Ultraflex gait analyzer. Materials and Methods: The study was based on the assessment of gait and weight-bearing pattern of both hips in patients who underwent total hip replacement and its comparison with an age and sex-matched control group. Twenty subjects of total arthroplasty group having unilateral involvement, operated by posterior approach at our institution with a minimum six-month postoperative period were selected. Control group was age and sex-matched, randomly selected from the general population. Gait analysis was done using Ultraflex gait analyzer. Gait parameters and vertical ground reaction forces assessment was done by measuring the gait cycle properties, step time parameters and VGRF variables. Data of affected limb was compared with unaffected limb as well as control group to assess the weight-bearing pattern. Statistical analysis was done by?t? test. Results: Frequency is reduced and gait cycle duration increased in total arthroplasty group as compared with control. Step time parameters including Step time, Stance time and Single support time are significantly reduced ( P value < .05 while Double support time and Single swing time are significantly increased ( P value < .05 in the THR group. Forces over each sensor are increased more on the unaffected limb of the THR group as compared to the control group. Vertical ground reaction force variables are also altered. Conclusion: Significant changes ( P value < .05 in gait parameters and vertical ground reaction forces show that gait pattern is not normalized after THR and weight-bearing is not equally shared by both hips. Patient walks with residual antalgic gait even after surgery, which results in abnormal loading around hip joints and the integrity of the prosthesis fixation could be compromised.

  20. A wearable force plate system for the continuous measurement of triaxial ground reaction force in biomechanical applications

    International Nuclear Information System (INIS)

    The ambulatory measurement of ground reaction force (GRF) and human motion under free-living conditions is convenient, inexpensive and never restricted to gait analysis in a laboratory environment and is therefore much desired by researchers and clinical doctors in biomedical applications. A wearable force plate system was developed by integrating small triaxial force sensors and three-dimensional (3D) inertial sensors for estimating dynamic triaxial GRF in biomechanical applications. The system, in comparison to existent systems, is characterized by being lightweight, thin and easy-to-wear. A six-axial force sensor (Nitta Co., Japan) was used as a verification measurement device to validate the static accuracy of the developed force plate. To evaluate the precision during dynamic gait measurements, we compared the measurements of the triaxial GRF and the center of pressure (CoP) by using the developed system with the reference measurements made using a stationary force plate and an optical motion analysis system. The root mean square (RMS) differences of the two transverse components (x- and y-axes) and the vertical component (z-axis) of the GRF were 4.3 ± 0.9 N, 6.0 ± 1.3 N and 12.1 ± 1.1 N, respectively, corresponding to 5.1 ± 1.1% and 6.5 ± 1% of the maximum of each transverse component and 1.3 ± 0.2% of the maximum vertical component of GRF. The RMS distance between the two systems' CoP traces was 3.2 ± 0.8 mm, corresponding to 1.2 ± 0.3% of the length of the shoe. Moreover, based on the results of the assessment of the influence of the system on natural gait, we found that gait was almost never affected. Therefore, the wearable system as an alternative device can be a potential solution for measuring CoP and triaxial GRF in non-laboratory environments

  1. Effects of slip-induced changes in ankle movement on muscle activity and ground reaction forces during running acceleration

    DEFF Research Database (Denmark)

    Ketabi, Shahin; Kersting, Uwe G.

    2013-01-01

    Ground contact in running is always linked to a minimum amount of slipping, e.g., during the early contact phase when horizontal forces are high compared to vertical forces. Studies have shown altered muscular activation when expecting slips [2-4]. It is not known what the mechanical effect of such slip episodes are on joint loading or performance. The aim of the present study was to examine the effect of changes in ankle movement on ankle joint loading, muscle activity, and ground reaction forces during linear acceleration.

  2. A Comparison of Golf Shoe Designs Highlights Greater Ground Reaction Forces with Shorter Irons

    OpenAIRE

    Paul Worsfold; Smith, Neal A.; Dyson, Rosemary J.

    2007-01-01

    In an effort to reduce golf turf damage the traditional metal spike golf shoe has been redesigned, but shoe-ground biomechanical evaluations have utilised artificial grass surfaces. Twenty-four golfers wore three different golf shoe traction designs (traditional metal spikes, alternative spikes, and a flat-soled shoe with no additional traction) when performing shots with a driver, 3 iron and 7 iron. Ground action forces were measured beneath the feet by two natural grass covered force platfo...

  3. Analysis of the center of pressure displacement, ground reaction force and muscular activity during step exercises.

    Science.gov (United States)

    Saad, Marcelo Camargo; Felício, Lilian Ramiro; Masullo, Catia de Lourdes; Liporaci, Rogério Ferreira; Bevilaqua-Grossi, Debora

    2011-10-01

    Anterior Knee Pain (AKP) is considered as one of the most common, yet misunderstood, knee pathologies. The aim of this study was to evaluate the displacement area of the center of pressure, Ground Reaction Force (GRF), and the electromyography activity of the hip and the quadriceps muscles in healthy and AKP individuals during the step-up and step-down exercises. Both groups (Control group and AKP group) were composed of 15 volunteers submitted to the exercises on a force plate. The AKP group presented greater displacement area of the center of pressure for all the situations evaluated than the Control group (p<0.05), as well as a lesser magnitude of the GRF during the step-down exercise. The AKP group presented lower electromyography activity than the Control group in all situations evaluated. AKP individuals do not have muscle imbalances; they present a lower electromyography activity of the stabilizing muscles of the patella and hip and show greater instability in activities such as step up and down compared to normal subjects. PMID:21865057

  4. Ground Reaction Force and Cadence during Stationary Running Sprint in Water and on Land.

    Science.gov (United States)

    de Brito Fontana, H; Ruschel, C; Haupenthal, A; Hubert, M; Roesler, H

    2015-06-01

    This study was aimed at analyzing the cadence (Cadmax) and the peak vertical ground reaction force (Fymax) during stationary running sprint on dry land and at hip and chest level of water immersion. We hypothesized that both Fymax and Cadmax depend on the level of immersion and that differences in Cadmax between immersions do not affect Fymax during stationary sprint. 32 subjects performed the exercise at maximum cadence at each immersion level and data were collected with force plates. The results show that Cadmax and Fymax decrease 17 and 58% from dry land to chest immersion respectively, with no effect of cadence on Fymax. While previous studies have shown similar neuromuscular responses between aquatic and on land stationary sprint, our results emphasize the differences in Fymax between environments and levels of immersion. Additionally, the characteristics of this exercise permit maximum movement speed in water to be close to the maximum speed on dry land. The valuable combination of reduced risk of orthopedic trauma with similar neuromuscular responses is provided by the stationary sprint exercise in water. The results of this study support the rationale behind the prescription of stationary sprinting in sports training sessions as well as rehabilitation programs. PMID:25700098

  5. Metabolic Rate and Ground Reaction Force During Motorized and Non-Motorized Treadmill Exercise

    Science.gov (United States)

    Everett, Meghan E.; Loehr, James A.; DeWitt, John K.; Laughlin, Mitzi; Lee, Stuart M. C.

    2010-01-01

    PURPOSE: To measure vertical ground reaction force (vGRF) and oxygen consumption (VO2) at several velocities during exercise using a ground-based version of the ISS treadmill in the M and NM modes. METHODS: Subjects (n = 20) walked or ran at 0.89, 1.34, 1.79, 2.24, 2.68, and 3.12 m/s while VO2 and vGRF data were collected. VO2 was measured using open-circuit spirometry (TrueOne 2400, Parvo-Medics). Data were averaged over the last 2 min of each 5-min stage. vGRF was measured in separate 15-s bouts at 125 Hz using custom-fitted pressure-sensing insoles (F-Scan Sport Sensors, Tekscan, Inc). A repeated-measures ANOVA was used to test for differences in VO2 and vGRF between M and NM and across speeds. Significance was set at P < 0.05. RESULTS: Most subjects were unable to exercise for 5 min at treadmill speeds above 1.79 m/s in the NM mode; however, vGRF data were obtained for all subjects at each speed in both modes. VO2 was approx.40% higher during NM than M exercise across treadmill speeds. vGRF increased with treadmill speed but was not different between modes. CONCLUSION: Higher VO2 with no change in vGRF suggests that the additional metabolic cost associated with NM treadmill exercise is accounted for in the horizontal forces required to move the treadmill belt. Although this may limit the exercise duration at faster speeds, high-intensity NM exercise activates the hamstrings and plantarflexors, which are not specifically targeted or well protected by other in-flight countermeasures.

  6. Landing ground reaction forces in figure skaters and non-skaters.

    Science.gov (United States)

    Saunders, Nathan W; Hanson, Nicholas; Koutakis, Panos; Chaudhari, Ajit M; Devor, Steven T

    2014-01-01

    Researchers and clinicians have suggested that overuse injuries to the lower back and lower extremities of figure skaters may be associated with the repeated high impact forces sustained during jump landings. Our primary aim was to compare the vertical ground reaction forces (GRFs) in freestyle figure skaters (n = 26) and non-skaters (n = 18) for the same barefoot single leg landing on a force plate from a 20 cm platform. Compared with non-skaters, skaters exhibited a significantly greater normalised peak GRF (3.50 ± 0.47 × body weight for skaters vs. 3.13 ± 0.45 × body weight for non-skaters), significantly shorter time to peak GRF (81.21 ± 14.01 ms for skaters vs. 93.81 ± 16.49 ms for non-skaters), and significantly longer time to stabilisation (TTS) of the GRF (2.38 ± 0.07 s for skaters vs. 2.22 ± 0.07 s for non-skaters). Skaters also confined their centre of pressure (CoP) to a significantly smaller mediolateral (M-L) (25%) and anterior-posterior (A-P) (40%) range during the landing phase, with the position of the CoP located in the mid to forefoot region. The narrower and more forward position of the CoP in skaters may at least partially explain the greater peak GRF, shorter time to peak, and longer TTS. Training and/or equipment modification serve as potential targets to decrease peak GRF by distributing it over a longer time period. More comprehensive studies including electromyography and motion capture are needed to fully characterise the unique figure skater landing strategy. PMID:24479611

  7. A Comparison of Accelerometers for Predicting Energy Expenditure and Vertical Ground Reaction Force in School-Age Children

    Science.gov (United States)

    Garcia, Anne W.; Langenthal, Carla R.; Angulo-Barroso, Rosa M.; Gross, M. Melissa

    2004-01-01

    In this pilot study of 16 children, we evaluated the reliability and validity of three accelerometers (Mini-Motionlogger [MML], Computer Science Applications, Inc. Actigraph [CSA], and BioTrainer) as indicators of energy expenditure and vertical ground reaction force. The children wore 2 of each type of monitor while they walked, ran, and…

  8. The Effects of Opposition and Gender on Knee Kinematics and Ground Reaction Force during Landing from Volleyball Block Jumps

    Science.gov (United States)

    Hughes, Gerwyn; Watkins, James; Owen, Nick

    2010-01-01

    The aim of this study was to examine the effect of opposition and gender on knee kinematics and ground reaction force during landing from a volleyball block jump. Six female and six male university volleyball players performed two landing tasks: (a) an unopposed and (b) an opposed volleyball block jump and landing. A 12-camera motion analysis…

  9. Gender Differences Among Sagittal Plane Knee Kinematic and Ground Reaction Force Characteristics During a Rapid Sprint and Cut Maneuver

    OpenAIRE

    James, C. Roger; Phillip S. Sizer; Starch, David W.; Lockhart, Thurmon E; Slauterbeck, James

    2004-01-01

    Women are more prone to anterior cruciate ligament (ACL) injury during cutting sports than men. The purpose of this study was to examine knee kinematic and ground reaction forces (GRF) differences between genders during cutting. Male and female athletes performed cutting trials while force platform and video data were recorded (180 Hz). Differences (p ? .05) were observed between groups for knee flexion at contact and GRF at maximum knee flexion. Women averaged 5.8° less flexion at contact...

  10. Frequency domain analysis of ground reaction force in preadolescents with and without Down syndrome.

    Science.gov (United States)

    Wu, Jianhua; Beerse, Matthew; Ajisafe, Toyin

    2014-06-01

    Children with Down syndrome (DS) display less stable and coordinated gait patterns in the time domain than their healthy peers. However, little is known about whether this group difference exists in the frequency domain. The purpose of this study was to investigate differences in vertical ground reaction force (GRF) in the frequency domain between preadolescents with and without DS. Twenty children at 7-10 years of age with and without DS participated in this study. Participants walked on an instrumented treadmill at two speeds with and without external ankle load. Vertical GRF was collected and the data was processed through a Fourier transform. Frequency content variables included fundamental frequency, power of the first five harmonics, and the frequency and number of harmonics at 95%, 99% and 99.5% of total power. Preadolescents with DS had a similar fundamental frequency as their healthy peers even though the DS group walked at slower speeds. The DS group displayed a different power spectrum of the first five harmonics and had the lower frequency and number of harmonics at 99% and 99.5% of total power. However, walking at a faster speed with external ankle load helped the DS group produce a power spectrum more similar to healthy children. Frequency content of vertical GRF provides additional assessment parameters in functional gait evaluation of children with DS. Treadmill intervention at a faster speed and with external ankle load appears to be clinically promising and needs further investigation. PMID:24685940

  11. Squat Ground Reaction Force on a Horizontal Squat Device, Free Weights, and Smith Machine

    Science.gov (United States)

    Scott-Pandorf, Melissa M.; Newby, Nathaniel J.; Caldwell, Erin; DeWitt, John K.; Peters, Brian T.

    2010-01-01

    Bed rest is an analog to spaceflight and advancement of exercise countermeasures is dependent on the development of exercise equipment that closely mimic actual upright exercise. The Horizontal Squat Device (HSD) was developed to allow a supine exerciser to perform squats that mimic upright squat exercise. PURPOSE: To compare vertical ground reaction force (GRFv) on the HSD with Free Weight (FW) or Smith Machine (SM) during squat exercise. METHODS: Subjects (3F, 3M) performed sets of squat exercise with increasing loads up to 1-repetition (rep) maximum. GRF data were collected and compared with previous GRF data for squat exercise performed with FW & SM. Loads on the HSD were adjusted to magnitudes comparable with FW & SM by subtracting the subject s body weight (BW). Peak GRFv for 45-, 55-, 64-, & 73-kg loads above BW were calculated. Percent (%) difference between HSD and the two upright conditions were computed. Effect size was calculated for the 45-kg load. RESULTS: Most subjects were unable to lift >45 kg on the HSD; however, 1 subject completed all loads. Anecdotal evidence suggested that most subjects shoulders or back failed before their legs. The mean % difference are shown. In the 45-kg condition, effect sizes were 0.37 & 0.83 (p>0.05) for HSD vs. FW and HSD vs. SM, respectively, indicating no differences between exercise modes. CONCLUSION: When BW was added to the target load, results indicated that vertical forces were similar to those in FW and SM exercise. The exercise prescription for the HSD should include a total external resistance equivalent to goal load plus subject BW. The HSD may be used as an analog to upright exercise in bed rest studies, but because most subjects were unable to lift >45 kg, it may be necessary to prescribe higher reps and lower loads to better target the leg musculature

  12. Effects of backpack weight on posture, gait patterns and ground reaction forces of male children with obesity during stair descent.

    Science.gov (United States)

    Song, Qipeng; Yu, Bing; Zhang, Cui; Sun, Wei; Mao, Dewei

    2014-01-01

    This study investigates the effects of backpack weight on posture, gait pattern, and ground reaction forces for children with obesity in an attempt to define a safe backpack weight limit for them. A total of 16 obese (11.19 ± 0.66 years of age) and 21 normal body weight (11.13 ± 0.69 years of age) schoolboys were recruited. Two force plates and two video cameras were used. Multivariate analysis of variance with repeated measures was employed. Obese children showed increased trunk and head forward inclination angle, gait cycle duration and stance phase, decreased swing phase, and increased ground reaction force in the medial-lateral and anterior-posterior directions when compared with male children with a normal body weight. The changes were observed even with an empty backpack in comparison with normal body weight children and a 15% increase in backpack weight led to further instability and damage on their already strained bodies. PMID:24650337

  13. A COMPARISON OF GOLF SHOE DESIGNS HIGHLIGHTS GREATER GROUND REACTION FORCES WITH SHORTER IRONS

    Directory of Open Access Journals (Sweden)

    Paul Worsfold

    2007-12-01

    Full Text Available In an effort to reduce golf turf damage the traditional metal spike golf shoe has been redesigned, but shoe-ground biomechanical evaluations have utilised artificial grass surfaces. Twenty-four golfers wore three different golf shoe traction designs (traditional metal spikes, alternative spikes, and a flat-soled shoe with no additional traction when performing shots with a driver, 3 iron and 7 iron. Ground action forces were measured beneath the feet by two natural grass covered force platforms. The maximum vertical force recorded at the back foot with the 3 iron and 7 iron was 0.82 BW (body weight and at the front foot 1.1 BW approximately in both the metal spike and alternative spike golf shoe designs. When using the driver these maximal vertical values were 0.49 BW at the back foot and 0.84 BW at the front foot. Furthermore, as performance of the backswing and then downswing necessitates a change in movement direction the range of force generated during the complete swing was calculated. In the metal spike shoe the vertical force generated at the back foot with both irons was 0.67 BW and at the front foot 0.96 BW with the 3 iron and 0.92 BW with the 7 iron. The back foot vertical force generated with the driver was 0.33 BW and at the front foot 0.83 BW wearing the metal spike shoe. Results indicated the greater force generation with the irons. When using the driver the more horizontal swing plane associated with the longer club reduced vertical forces at the back and front foot. However, the mediolateral force generated across each foot in the metal and alternative spike shoes when using the driver was greater than when the irons were used. The coefficient of friction was 0. 62 at the back and front foot whichever shoe was worn or club used

  14. Functional knee brace use effect on peak vertical ground reaction forces during drop jump landing.

    Science.gov (United States)

    Rishiraj, Neetu; Taunton, Jack E; Lloyd-Smith, Robert; Regan, William; Niven, Brian; Woollard, Robert

    2012-02-01

    PURPOSE: The aim of the study was to investigate the landing strategies used by non-injured athletes while wearing functional knee braces (FKB, BR condition) during a drop jump task compared with non-injured, non-braced (NBR condition) subjects and also to ascertain whether accommodation to a FKB was possible by non-injured BR subjects. METHODS: Twenty-three healthy male provincial and national basketball and field hockey athletes (age, 19.4 ± 3.0 years) were tested. Each subject was provided with a custom-fitted FKB. Five NBR testing sessions were performed over 3 days followed by five BR testing sessions also over 3 days, for a total of 17.5 h of testing per condition. Each subject performed eight trials of the drop jump task during each testing session per condition. Single-leg peak vertical ground reaction forces (PVGRF) and the time to PVGRF were recorded for each NBR and BR trail. RESULTS: The BR group mean PVGRF at landing was significantly lower (1,628 ± 405 N, 2.1 ± 0.5 BW versus 1,715 ± 403 N, 2.2 ± 0.5 BW, F (1,22) = 6.83, P = 0.01) compared with NBR subjects, respectively. The group mean time to PVGRF was not statistically longer during the BR condition (F (1,22) = 0.967, P = 0.3). Further, an accommodation trend was noted as percent performance difference decreased with continued FKB use. CONCLUSIONS: The significantly lower group mean PVGRF while using a FKB could keep traumatic forces from reaching the ACL until the active neuromuscular restraints are activated to provide protection to the knee joint ligaments. Also, accommodation to FKB is possible after approximately 14.0 h of brace use. The results of this paper will assist clinicians in providing information to their patients regarding a FKB ability to offer protection to an ACL-deficient knee or to address concerns about early muscle fatigue, energy expenditure, heart rate, and decrease in performance level. LEVEL OF EVIDENCE: Prospective study, Level I. PMID:22293898

  15. NUMBER OF TRIALS NECESSARY TO ACHIEVE PERFORMANCE STABILITY OF SELECTED GROUND REACTION FORCE VARIABLES DURING LANDING

    Directory of Open Access Journals (Sweden)

    C. Roger James

    2007-03-01

    Full Text Available The objectives were to determine the number of trials necessary to achieve performance stability of selected ground reaction force (GRF variables during landing and to compare two methods of determining stability. Ten subjects divided into two groups each completed a minimum of 20 drop or step-off landings from 0.60 or 0.61 m onto a force platform (1000 Hz. Five vertical GRF variables (first and second peaks, average loading rates to these peaks, and impulse were quantified during the initial 100 ms post-contact period. Test-retest reliability (stability was determined using two methods: (1 intra-class correlation coefficient (ICC analysis, and (2 sequential averaging analysis. Results of the ICC analysis indicated that an average of four trials (mean 3.8 ± 2.7 Group 1; 3.6 ± 1.7 Group 2 were necessary to achieve maximum ICC values. Maximum ICC values ranged from 0.55 to 0.99 and all were significantly (p < 0. 05 different from zero. Results of the sequential averaging analysis revealed that an average of 12 trials (mean 11.7 ± 3.1 Group 1; 11.5 ± 4.5 Group 2 were necessary to achieve performance stability using criteria previously reported in the literature. Using 10 reference trials, the sequential averaging technique required standard deviation criterion values of 0.60 and 0.49 for Groups 1 and 2, respectively, in order to approximate the ICC results. The results of the study suggest that the ICC might be a less conservative, but more objective method for determining stability, especially when compared to previous applications of the sequential averaging technique. Moreover, criteria for implementing the sequential averaging technique can be adjusted so that results closely approximate the results from ICC. In conclusion, subjects in landing experiments should perform a minimum of four and possibly as many as eight trials to achieve performance stability of selected GRF variables. Researchers should use this information to plan future studies and to report the stability of GRF data in landing experiments

  16. A Wearable Ground Reaction Force Sensor System and Its Application to the Measurement of Extrinsic Gait Variability

    OpenAIRE

    Kyoko Shibata; Yoshio Inoue; Tao Liu(Institut für Theoretische Teilchenphysik, Karlsruhe Institute of Technology (KIT), D-76128 Karlsruhe, Germany)

    2010-01-01

    Wearable sensors for gait analysis are attracting wide interest. In this paper, a wearable ground reaction force (GRF) sensor system and its application to measure extrinsic gait variability are presented. To validate the GRF and centre of pressure (CoP) measurements of the sensor system and examine the effectiveness of the proposed method for gait analysis, we conducted an experimental study on seven volunteer subjects. Based on the assessment of the influence of the sensor system on natural...

  17. Multi-body simulation of a canine hind limb: model development, experimental validation and calculation of ground reaction forces

    Directory of Open Access Journals (Sweden)

    Wefstaedt Patrick

    2009-11-01

    Full Text Available Abstract Background Among other causes the long-term result of hip prostheses in dogs is determined by aseptic loosening. A prevention of prosthesis complications can be achieved by an optimization of the tribological system which finally results in improved implant duration. In this context a computerized model for the calculation of hip joint loadings during different motions would be of benefit. In a first step in the development of such an inverse dynamic multi-body simulation (MBS- model we here present the setup of a canine hind limb model applicable for the calculation of ground reaction forces. Methods The anatomical geometries of the MBS-model have been established using computer tomography- (CT- and magnetic resonance imaging- (MRI- data. The CT-data were collected from the pelvis, femora, tibiae and pads of a mixed-breed adult dog. Geometric information about 22 muscles of the pelvic extremity of 4 mixed-breed adult dogs was determined using MRI. Kinematic and kinetic data obtained by motion analysis of a clinically healthy dog during a gait cycle (1 m/s on an instrumented treadmill were used to drive the model in the multi-body simulation. Results and Discussion As a result the vertical ground reaction forces (z-direction calculated by the MBS-system show a maximum deviation of 1.75%BW for the left and 4.65%BW for the right hind limb from the treadmill measurements. The calculated peak ground reaction forces in z- and y-direction were found to be comparable to the treadmill measurements, whereas the curve characteristics of the forces in y-direction were not in complete alignment. Conclusion In conclusion, it could be demonstrated that the developed MBS-model is suitable for simulating ground reaction forces of dogs during walking. In forthcoming investigations the model will be developed further for the calculation of forces and moments acting on the hip joint during different movements, which can be of help in context with the in silico development and testing of hip prostheses.

  18. Gender difference in older adult's utilization of gravitational and ground reaction force in regulation of angular momentum during stair descent.

    Science.gov (United States)

    Singhal, Kunal; Kim, Jemin; Casebolt, Jeffrey; Lee, Sangwoo; Han, Ki-Hoon; Kwon, Young-Hoo

    2015-06-01

    Angular momentum of the body is a highly controlled quantity signifying stability, therefore, it is essential to understand its regulation during stair descent. The purpose of this study was to investigate how older adults use gravity and ground reaction force to regulate the angular momentum of the body during stair descent. A total of 28 participants (12 male and 16 female; 68.5years and 69.0years of mean age respectively) performed stair descent from a level walk in a step-over-step manner at a self-selected speed over a custom made three-step staircase with embedded force plates. Kinematic and force data were used to calculate angular momentum, gravitational moment, and ground reaction force moment about the stance foot center of pressure. Women show a significantly greater change in normalized angular momentum (0.92Nms/Kgm; p=.004) as compared to men (0.45Nms/Kgm). Women produce higher normalized GRF (p=.031) during the double support phase. The angular momentum changes show largest backward regulation for Step 0 and forward regulation for Step 2. This greater difference in overall change in the angular momentum in women may explain their increased risk of fall over the stairs. PMID:25846952

  19. Predicting Complete Ground Reaction Forces and Moments During Gait With Insole Plantar Pressure Information Using a Wavelet Neural Network.

    Science.gov (United States)

    Sim, Taeyong; Kwon, Hyunbin; Oh, Seung Eel; Joo, Su-Bin; Choi, Ahnryul; Heo, Hyun Mu; Kim, Kisun; Mun, Joung Hwan

    2015-09-01

    In general, three-dimensional ground reaction forces (GRFs) and ground reaction moments (GRMs) that occur during human gait are measured using a force plate, which are expensive and have spatial limitations. Therefore, we proposed a prediction model for GRFs and GRMs, which only uses plantar pressure information measured from insole pressure sensors with a wavelet neural network (WNN) and principal component analysis-mutual information (PCA-MI). For this, the prediction model estimated GRFs and GRMs with three different gait speeds (slow, normal, and fast groups) and healthy/pathological gait patterns (healthy and adolescent idiopathic scoliosis (AIS) groups). Model performance was validated using correlation coefficients (r) and the normalized root mean square error (NRMSE%) and was compared to the prediction accuracy of the previous methods using the same dataset. As a result, the performance of the GRF and GRM prediction model proposed in this study (slow group: r?=?0.840-0.989 and NRMSE%?=?10.693-15.894%; normal group: r?=?0.847-0.988 and NRMSE% =?10.920-19.216%; fast group: r?=?0.823-0.953 and NRMSE%?=?12.009-20.182%; healthy group: r?=?0.836-0.976 and NRMSE%?=?12.920-18.088%; and AIS group: r?=?0.917-0.993 and NRMSE%?=?7.914-15.671%) was better than that of the prediction models suggested in previous studies for every group and component (p?

  20. The influence of gait cadence on the ground reaction forces and plantar pressures during load carriage of young adults.

    Science.gov (United States)

    Castro, Marcelo P; Figueiredo, Maria Cristina; Abreu, Sofia; Sousa, Helena; Machado, Leandro; Santos, Rubim; Vilas-Boas, João Paulo

    2015-07-01

    Biomechanical gait parameters--ground reaction forces (GRFs) and plantar pressures--during load carriage of young adults were compared at a low gait cadence and a high gait cadence. Differences between load carriage and normal walking during both gait cadences were also assessed. A force plate and an in-shoe plantar pressure system were used to assess 60 adults while they were walking either normally (unloaded condition) or wearing a backpack (loaded condition) at low (70 steps per minute) and high gait cadences (120 steps per minute). GRF and plantar pressure peaks were scaled to body weight (or body weight plus backpack weight). With medium to high effect sizes we found greater anterior-posterior and vertical GRFs and greater plantar pressure peaks in the rearfoot, forefoot and hallux when the participants walked carrying a backpack at high gait cadences compared to walking at low gait cadences. Differences between loaded and unloaded conditions in both gait cadences were also observed. PMID:25766421

  1. Gait Phases Recognition from Accelerations and Ground Reaction Forces: Application of Neural Networks

    Directory of Open Access Journals (Sweden)

    S. Rafajlovi?

    2009-06-01

    Full Text Available The goal of this study was to test the applicability of accelerometer as the sensor for assessment of the walking. We present here the comparison of gait phases detected from the data recorded by force sensing resistors mounted in the shoe insoles, non-processed acceleration and processed acceleration perpendicular to the direction of the foot. The gait phases in all three cases were detected by means of a neural network. The output from the neural network was the gait phase, while the inputs were data from the sensors. The results show that the errors were in the ranges: 30 ms (2.7% – force sensors; 150 ms (13.6% – nonprocessed acceleration, and 120 ms (11% – processed acceleration data. This result suggests that it is possible to use the accelerometer as the gait phase detector, however, with the knowledge that the gait phases are time shifted for about 100 ms with respect the neural network predicted times.

  2. The relationship between bone mechanical properties and ground reaction forces in normal and hypermuscular mice

    OpenAIRE

    Schmitt, Daniel; Zumwalt, Ann C.; Hamrick, Mark W.

    2010-01-01

    Understanding the relationship between external load and bone morphology is critical for understanding adaptations to load in extant animals and inferring behavior in extinct forms. Yet the relationship bony anatomy and load is poorly understood, with empirical studies often producing conflicting results. It is widely assumed in many ecological and paleontological studies that bone size and strength reflects the forces experience by the bone in-vivo. This study examines that assumption by pro...

  3. Gait Phases Recognition from Accelerations and Ground Reaction Forces: Application of Neural Networks

    OpenAIRE

    S. Rafajlovi?; M. Gavrilovi?; N. Mijailovi?

    2009-01-01

    The goal of this study was to test the applicability of accelerometer as the sensor for assessment of the walking. We present here the comparison of gait phases detected from the data recorded by force sensing resistors mounted in the shoe insoles, non-processed acceleration and processed acceleration perpendicular to the direction of the foot. The gait phases in all three cases were detected by means of a neural network. The output from the neural network was the gait phase, while the inputs...

  4. Ground reaction forces and throwing performance in elite and novice players in two types of handball shot.

    Science.gov (United States)

    Rousanoglou, Elissavet; Noutsos, Konstantinos; Bayios, Ioannis; Boudolos, Konstantinos

    2014-03-27

    The purpose of this study was to examine the differences in the ground reaction force (GRF) patterns between elite and novice players during two types of handball shots, as well as the relationships between throwing performance and the GRF variables. Ball velocity and throwing accuracy were measured during jump shots and 3-step shots performed by 15 elite and 15 novice players. The GRF pattern was recorded for the vertical and the anterior-posterior GRF components (Kistler forceplate type-9281, 750Hz). One-way ANOVA was used for the group differences and the Pearson coefficient for the correlation between throwing performance and GRF variables (SPSS 21.0, p ? 0.05). The elite players performed better in both types of shot. Both groups developed consistent and similar GRF patterns, except for the novices' inconsistent Fz pattern in the 3-step shot. The GRF variables differed significantly between groups in the 3-step shot (p ? 0.05). Significant correlations were found only for ball velocity and predominantly for the novice players during the 3-step shot (p ? 0.05). The results possibly highlight a shortage in the novice ability to effectively reduce their forward momentum so as to provide a stable base of support for the momentum transfer up the kinetic chain, a situation that may predispose athletes to injury. PMID:25031672

  5. The Effect of pPoron Layered Insole on Ground Reaction Force in Comparison with Common Insole on Subjects with Flexible Flat foot

    Directory of Open Access Journals (Sweden)

    F Khanmohammad

    2012-01-01

    Full Text Available Background: Flexible flat foot is a congenital common deformity in lower extremity associated with ligamentus laxity. This deformity may cause hammer toe, heel spur, inflammation of achille tendon, early muscle fatigue during sport, foot imbalance and pain in leg, knee and hip. The use of insole with medial arch support considered as one of the common treatments for patients. The purpose of this study was to determine the effect of a composite insole, Ethyl Vinyl Acetate (EVA with Poron layer on ground reaction force on subjects with flexible flat foot in comparison with common EVA insole. Materials and Methods: Fifty two subjects (14 Male and 38 female between 18-40 years of age with flexible flat foot participated in this study. Twenty six subjects received Poron insole (EVA with Poron layer and 26 subjects received common EVA insole. After assessment each subject asked to walk with normal speed across two force plate in two conditions, walking with insole and shoe and walking without insole. Then each subject asked to use insole for forty hours during two weeks. Vertical ground reaction force in the first session and after two weeks was assessed.Results: Impact force and first peak of vertical ground reaction force (F1 with Poron insole in comparison with shoe significantly increased in second session (P<0.05. The second peak (F3 with common insole in comparison with shoe significantly increased in second session (P<0.05. Significant reduction was noted in first peak (F1 with common insole in second session in comparison with first session (P<0.05. There was no observable significant difference in two groups before and after intervention.Conclusion: The results of this preliminary study show that both insoles change vertical ground reaction force in comparison with shoe alone. But using a composite Poron Layer on EVA insole has not demonstrated a significant difference with common arch support insoles. Therefore appli

  6. A comparison of lower limb EMG and ground reaction forces between barefoot and shod gait in participants with diabetic neuropathic and healthy controls

    OpenAIRE

    Akashi Paula MH; Sacco Isabel CN; Hennig Ewald M

    2010-01-01

    Abstract Background It is known that when barefoot, gait biomechanics of diabetic neuropathic patients differ from non-diabetic individuals. However, it is still unknown whether these biomechanical changes are also present during shod gait which is clinically advised for these patients. This study investigated the effect of the participants own shoes on gait biomechanics in diabetic neuropathic individuals compared to barefoot gait patterns and healthy controls. Methods Ground reaction forces...

  7. Predição da força de reação do solo durante a corrida na água / Prediction of ground reaction force during water immersion running

    Scientific Electronic Library Online (English)

    Alessandro, Haupenthal; Heiliane de Brito, Fontana; Caroline, Ruschel; Helio, Roesler; Adriano Ferreti, Borgatto.

    2010-09-01

    Full Text Available Este estudo visou desenvolver um modelo para a predição da força de reação do solo na corrida subaquática. Participaram 20 sujeitos (9 homens e 11 mulheres), que realizaram corrida subaquática em dois níveis de imersão e três velocidades. Para cada sujeito foram coletadas seis passagens válidas em c [...] ada condição, com a utilização de uma plataforma subaquática de força. O modelo para predição da força foi construído por regressão linear múltipla. Foram consideradas variáveis dependentes a componente vertical e a componente ântero-posterior da força de reação do solo. As variáveis imersão, sexo, velocidade, massa corporal, densidade corporal e percentual de gordura foram consideradas independentes. Permaneceu no modelo final de regressão para a componente vertical a velocidade (p Abstract in english This study aimed at developing a model to predict ground reaction force during deep-water running. A total of 20 subjects ((9 men, 11 women) ran in water at two immersion levels and three different speeds. Each subject performed six valid trials in each condition, data being captured by an underwate [...] r force plate. The force prediction model was build by multiple linear regression. Dependent variables were the vertical and anteroposterior components of the ground reaction force; independent variables were runners' immersion, sex, speed, body mass, body density, and percentage of fat. At the final regression model for the vertical component, only speed remained (p

  8. A comparison of lower limb EMG and ground reaction forces between barefoot and shod gait in participants with diabetic neuropathic and healthy controls

    Directory of Open Access Journals (Sweden)

    Akashi Paula MH

    2010-02-01

    Full Text Available Abstract Background It is known that when barefoot, gait biomechanics of diabetic neuropathic patients differ from non-diabetic individuals. However, it is still unknown whether these biomechanical changes are also present during shod gait which is clinically advised for these patients. This study investigated the effect of the participants own shoes on gait biomechanics in diabetic neuropathic individuals compared to barefoot gait patterns and healthy controls. Methods Ground reaction forces and lower limb EMG activities were analyzed in 21 non-diabetic adults (50.9 ± 7.3 yr, 24.3 ± 2.6 kg/m2 and 24 diabetic neuropathic participants (55.2 ± 7.9 yr, 27.0 ± 4.4 kg/m2. EMG patterns of vastus lateralis, lateral gastrocnemius and tibialis anterior, along with the vertical and antero-posterior ground reaction forces were studied during shod and barefoot gait. Results Regardless of the disease, walking with shoes promoted an increase in the first peak vertical force and the peak horizontal propulsive force. Diabetic individuals had a delay in the lateral gastrocnemius EMG activity with no delay in the vastus lateralis. They also demonstrated a higher peak horizontal braking force walking with shoes compared to barefoot. Diabetic participants also had a smaller second peak vertical force in shod gait and a delay in the vastus lateralis EMG activity in barefoot gait compared to controls. Conclusions The change in plantar sensory information that occurs when wearing shoes revealed a different motor strategy in diabetic individuals. Walking with shoes did not attenuate vertical forces in either group. Though changes in motor strategy were apparent, the biomechanical did not support the argument that the use of shoes contributes to altered motor responses during gait.

  9. Força de reação do solo como subsídio para prescrição de exercícios aquáticos: estudo de caso / Ground reaction force as a subsidy for prescribing aquatic exercises: case study

    Scientific Electronic Library Online (English)

    Alessandro, Haupenthal; Caroline, Ruschel; Marcel, Hubert; Heiliane de Brito, Fontana; Helio, Roesler.

    2010-06-01

    Full Text Available OBJETIVO: Comparar a componente vertical da força de reação do solo nos exercícios de caminhada, corrida com deslocamento, corrida estacionária e salto vertical, realizados em ambiente aquático em diferentes níveis de imersão. MÉTODO: Participou deste estudo de caso um sujeito do sexo masculino (27 [...] anos, 1,80 m e 84,3 kg). Utilizou-se para a coleta de dados uma plataforma subaquática de força posicionada no fundo de uma piscina térmica. O sujeito realizou 30 tentativas válidas de cada exercício, imerso nos níveis do processo xifoide e do quadril. Os dados foram analisados com a utilização da estatística descritiva, teste "t" de Student para amostras pareadas e ANOVA, para medidas repetidas (p Abstract in english OBJECTIVE: To compare the vertical component of the ground reaction force in the exercises of walking, running, stationary running and vertical jump in the water, performed in different levels of immersion. METHODS: This case study was conducted with one subject (male, 27 years, 1,80 m and 84,3 kg). [...] An underwater force plate was used for data collection, placed at the bottom of a thermal swimming pool. The subject performed 30 valid passages for each exercise in two immersion levels: xiphoid process and hip. Data were analyzed through descriptive statistics, Student's "t" test for paired samples and ANOVA for repeated measures (p

  10. ANALYSIS OF THE VERTICAL GROUND REACTION FORCES AND TEMPORAL FACTORS IN THE LANDING PHASE OF A COUNTERMOVEMENT JUMP

    Directory of Open Access Journals (Sweden)

    Daniel Rojano Ortega

    2010-06-01

    Full Text Available In most common bilateral landings of vertical jumps, there are two peak forces (F1 and F2 in the force-time curve. The combination of these peak forces and the high frequency of jumps during sports produce a large amount of stress in the joints of the lower limbs which can be determinant of injury. The aim of this study was to find possible relationships between the jump height and F1 and F2, between F1 and F2 themselves, and between F1, F2, the time they appear (T1 and T2, respectively and the length of the impact absorption phase (T. Thirty semi-professional football players made five countermovement jumps and the highest jump of each player was analyzed. They were instructed to perform the jumps with maximum effort and to land first with the balls of their feet and then with their heels. All the data were collected using a Kistler Quattro Jump force plate with a sample rate of 500 Hz. Quattro Jump Software, v.1.0.9.0., was used. There was neither significant correlation between T1 and F1 nor between T1 and F2. There was a significant positive correlation between flight height (FH and F1 (r = 0.584, p = 0.01 but no significant correlation between FH and F2. A significant positive correlation between F1 and T2 (r = 0.418, p < 0.05 and a significant negative correlation between F2 and T2 (r = -0.406, p < 0.05 were also found. There is a significant negative correlation between T2 and T (r = -0. 443, p < 0.05. T1 has a little effect in the impact absorption process. F1 increases with increasing T2 but F2 decreases with increasing T2. Besides, increasing T2, with the objective of decreasing F2, makes the whole impact absorption shorter and the jump landing faster.

  11. Effects of shoeing on limb movement and ground reaction forces in Icelandic horses at walk, tölt and trot.

    Science.gov (United States)

    Waldern, Nina M; Wiestner, Thomas; Ramseier, Lea C; Amport, Claude; Weishaupt, Michael A

    2013-12-01

    Tölt is a symmetric four-beat gait with a speed range extending into that of trot and canter. Specific shoeing methods, such as unnaturally high and long hooves, are used to enforce individual gait predisposition. The aim of this study was to assess the consequences of this shoeing style on loading and movement of the limbs at walk, tölt and trot, and at different velocities. Simultaneous kinetic and kinematic gait analysis was carried out at walk (1.4m/s) and at two tölting and trotting speeds (3.3m/s and 3.9 m/s) on an instrumented treadmill. Thirteen sound Icelandic horses were first measured with high, long front hooves (SH) and, 1 week later, after trimming the hooves according to standard shoeing principles (SN). Comparing SH with SN, front hooves had 21 ± 5 mm longer dorsal hoof walls, and the shoeing material per hoof was 273 ± 50 g heavier. In all three gaits, gait quality, as it is currently judged, was improved with SH due to a lower stride rate, a longer stride length and a higher, but not wider, forelimb protraction arc, which were also positively associated with speed. Forelimb-hind limb balance remained unchanged, but limb impulses were higher. Apart from an increase of ? 2.2% in the forelimbs at the faster speed of both tölt and trot, SH had little influence on vertical peak forces. PMID:24360730

  12. Hip joint reaction force - review

    Directory of Open Access Journals (Sweden)

    Matej Daniel

    2007-02-01

    Full Text Available This paper provides a review of various methods used to determine reaction force in the human hip: from simple statical models through dynamical inverse dynamics model to experimental measurements. Special attention is taken to inverse dynamics modeling.

  13. Influence of pressure-relief insoles developed for loaded gait (backpackers and obese people) on plantar pressure distribution and ground reaction forces.

    Science.gov (United States)

    Peduzzi de Castro, Marcelo; Abreu, Sofia; Pinto, Viviana; Santos, Rubim; Machado, Leandro; Vaz, Mario; Vilas-Boas, João Paulo

    2014-07-01

    The aims of this study were to test the effects of two pressure relief insoles developed for backpackers and obese people on the ground reaction forces (GRF) and plantar pressure peaks during gait; and to compare the GRF and plantar pressures among normal-weight, backpackers, and obese participants. Based on GRF, plantar pressures, and finite element analysis two insoles were manufactured: flat cork-based insole with (i) corkgel in the rearfoot and forefoot (SLS1) and with (ii) poron foam in the great toe and lateral forefoot (SLS2). Gait data were recorded from 21 normal-weight/backpackers and 10 obese participants. The SLS1 did not influence the GRF, but it relieved the pressure peaks for both backpackers and obese participants. In SLS2 the load acceptance GRF peak was lower; however, it did not reduce the plantar pressure peaks. The GRF and plantar pressure gait pattern were different among the normal-weight, backpackers and obese participants. PMID:24468683

  14. Computerized identification and classification of stance phases as made by front og hind feet of walking cows based on 3-dimensional ground reaction forces

    DEFF Research Database (Denmark)

    SkjØth, F; Thorup, Vivi MØrkØre

    2013-01-01

    Lameness is a frequent disorder in dairy cows and in large dairy herds manual lameness detection is a time-consuming task. This study describes a method for automatic identification of stance phases in walking cows, and their classification as made by a front or a hind foot based on ground reaction force information. Features were derived from measurements made using two parallel 3-dimensional force plates. The approach presented is based on clustering of Centre of Pressure (COP) trace points over space and time, combined with logical sequencing of stance phases based on the dynamics of quadrupedal walking. The clusters were identified as full or truncated (incomplete) stance phases furthermore the stance phases were classified as originating from a front or hind foot. Data from 370 walking trials made by 9 cows on 5 experiment days were used to test the method. Four cows were moderately lame at experimental onset. On average 5.1 stance phases per cow per trial were obtained of which 3.2 were classified as full stance phases and therefore appropriate for further gait analysis (the latter not being the scope of this study). Of the 2617 identified clusters 1844 were classified as stance phases, of these 1146 (62%) were automatically identified as full stance phases and classified as made by a front or hind foot. As intended, the procedures did not favour identification of stance phases of healthy cows over lame cows. In addition, a human observer evaluated the stance phases by visual inspection, revealing a very low discrepancy (3.5%) between manual and automated approaches. Further, a sensitivity test indicated large robustness in the automatic procedures. In conclusion, the experimental setup combined with the computerized procedures described in the present study resulted in a high number of stance phases obtained per trial. It is thus a combination which has the potential to enable unsupervised gait analysis based on data collected automatically on-farm

  15. Reproducibility of the spatio-temporal variables and the ground reaction forces walking with fire fighting boots REPRODUCIBILIDAD DE LAS VARIABLES ESPACIO-TEMPORALES Y DE LAS COMPONENTES DE LA FUERZA DE REACCIÓN DEL SUELO EN LA MARCHA CON BOTAS DE BOMBERO [Reproducibility of the spatio-temporal variables and the ground reaction forces walking with fire fighting boo

    Directory of Open Access Journals (Sweden)

    Begoña Gavilanes

    2010-11-01

    Full Text Available AbstractThe aim of this study is to analyze the reproducibility of the spatio-temporal variables and the ground reaction forces (GRF when walking with fire fighting boots in comparison to walking with low calf shoes. Spatio-temporal parameters and the variables related to the three components of the GRF of 39 people were recorded under two different walking conditions. A T-test to contrast the difference between the coefficients of variation (CV in both conditions was used. The CV of the spatio-temporal variables (i.e velocity (V, condition I = 2.01%; condition II = 1.81%, of the vertical (i.e. contact force (FZA of the left foot, condition I = 2.54%; condition II = 2.73% and of the antero-posterior GRF (i.e. maximum force (FXMAX of the left foot, condition I = 4.47%; condition II = 4.59% was lower than 12.5%, suggesting that these variables could be used to analyze the influence of fire fighting boots on the gait. However, the low reproducibility showed by medium-lateral parameters does not allow to use them. Apart from the bipodal phase no differences were found between the two walking conditions. Key words: biomechanics, footwear, variability.ResumenEl objetivo del presente trabajo es analizar la reproducibilidad de las variables espacio-temporales y de la fuerza de reacción del suelo (FRS durante la marcha con botas de bombero y compararla con la mostrada durante la marcha con calzado de cuero sin caña. Se registraron las variables espacio-temporales de 39 personas así como las variables que definen las tres componentes de la FRS con dos tipos de calzado diferente. Se utilizó la prueba T para contrastar la hipótesis referida a la diferencia del coeficiente de variación (CV entre los dos tipos de calzado. El CV de las variables espacio-temporales (p. ej. velocidad (V, condición I = 2,01%; condición II = 1,81%, así como de las que definen la componente vertical (p. ej. fuerza de apoyo (FZA del pie izquierdo, condición I = 2,54%; condición II = 2,73% y antero-posterior (p. ej. fuerza máxima (FXMAX del pie izquierdo, condición I = 4,47%; condición II = 4,59% de la FRS fue inferior a 12,5%, sugiriendo que estas variables pueden ser utilizadas para analizar la influencia de las botas de bombero sobre la marcha. La baja reproducibilidad mostrada por las variables que definen la componente medio-lateral desaconseja la utilización de las mismas para evaluar el efecto de las botas de bombero sobre la marcha. A excepción del tiempo de apoyo bipodal, el resto de variables durante la marcha con botas de bombero no mostró una variabilidad diferente a la obtenida durante la marcha con calzado de cuero sin caña.Palabras clave: biomecánica, calzado, variabilidad. AbstractThe aim of this study is to analyze the reproducibility of the spatio-temporal variables and the ground reaction forces (GRF when walking with fire fighting boots in comparison to walking with low calf shoes. Spatio-temporal parameters and the variables related to the three components of the GRF of 39 people were recorded under two different walking conditions. A T-test to contrast the difference between the coefficients of variation (CV in both conditions was used. The CV of the spatio-temporal variables (i.e velocity (V, condition I = 2.01%; condition II = 1.81%, of the vertical (i.e. contact force (FZA of the left foot, condition I = 2.54%; condition II = 2.73% and of the antero-posterior GRF (i.e. maximum force (FXMAX of the left foot, condition I = 4.47%; condition II = 4.59% was lower than 12.5%, suggesting that these variables could be used to analyze the influence of fire fighting boots on the gait. However, the low reproducibility showed by medium-lateral parameters does not allow to use them. Apart from the bipodal phase no differences were found between the two walking conditions.Key words: biomechanics, footwear, variability.

  16. Estudo da variabilidade das forças de reação do solo na aquisição do andar independente em bebês / A study of ground reaction forces variability during acquisition of independent gait in toddlers

    Scientific Electronic Library Online (English)

    Giovana, Levada; Paula Hentschel Lobo da, Costa.

    2012-06-01

    Full Text Available Este estudo avaliou o comportamento das forças de reação do solo (FRS) nos primeiros meses do andar independente, a fim de identificar mudanças na capacidade infantil de propulsionar e equilibrar o corpo em condição dinâmica. Foram avaliadas no período de três meses dez crianças com idade de 13 mese [...] s na primeira avaliação. As crianças caminharam em uma passarela de cinco metros de comprimento com duas plataformas de força embutidas. Foram estudadas magnitudes máximas e mínimas das FRS e as respectivas variabilidades. As avaliações foram comparadas através do teste não-paramétrico ANOVA de Friedman (p Abstract in english This study aimed to describe ground reaction forces' profiles during toddler's gait at the first months of the acquisition phase of independent walking, in order to identify whether there are changes in the ability to propel and balance the body in this dynamic condition. Ten thirteen-month old todd [...] lers volunteered to the study and were evaluated three times in a three-month interval. The toddlers walked over a 5 m long walkway with two force plates fixed at ground level. Vertical and horizontal peak reaction forces and variability coefficients were selected for analysis. To compare the results of the three evaluations ANOVA Friedman's tests were used at 5% level of significance. The walking experience achieved by the toddlers month after month was not sufficient to significantly change the biomechanical selected variables and statistically significant differences were not found for the selected variables along three months. However, a reduction in the variability coefficient for the vertical reaction forces suggests development towards an increasingly mature gait pattern.

  17. A influência do uso acumulado de calçados de corrida sobre a força de reação do solo e as respostas de pressão plantar The influence of running shoes cumulative usage on the ground reaction forces and plantar pressure responses

    Directory of Open Access Journals (Sweden)

    Roberto Bianco

    2011-12-01

    Full Text Available Acredita-se que a eficiência do calçado seja afetada pelo uso prolongado, mas as alterações biomecânicas ainda não estão bem compreendidas. O objetivo deste estudo é analisar a influência do uso de calçados de corrida na força de reação do solo e os parâmetros de pressão plantar. Três corredores do sexo masculino receberam quatro calçados de corrida para usarem em suas sessões de treinamento. O Sistema Gaitway e o Sistema de F-scan foram usados para registrar a força de reação do solo e parâmetros pressão plantar em diferentes regiões do pé. As coletas ocorreram em quatro momentos: novo e 100, 200 e 300 km de uso. O primeiro pico diminuiu da condição novo para os 300 km de uso (p The prolonged use of a running shoe is thought to affect the efficiency of its impact attenuation properties. However, its effect over biomechanical variables has yet not been well understood. The aim of this study was to examine the influence of running shoe usage on ground reaction force and plantar pressure parameters. Three male runners received four running shoes each to use at their training sessions. The Gaitway System was used to register the vertical component of the ground reaction force, whereas the contact area and peak plantar pressure at different regions of the foot were assessed via the the F-scan System. Data collection occurred at baseline (when the shoes were new - New and after 100, 200 and 300km of use. The first peak decreased significantly from New to 300km (p < 0.01 and the loading rate showed a significant decrease at 200km in relation to the New condition (p < 0.01. Total area increased significantly from New to 100km (p < 0.01 of use and maintained a similar value when compared with the other conditions. There was a continuous and significant decrease (p < 0.01 on forefoot peak pressure as the mileage increased from New to 300km. The hallux peak pressure values were significantly smaller (p < 0.01 at 300km when compared with the New condition. Considering that the first peak, loading rate and plantar peak pressure values did not increase and that the plantar total contact area increased, it can be concluded that the running shoe did not suffer consistent alterations in ground reaction force and in plantar pressure after 300km of use.

  18. Effects of ground and joint reaction force exercise on lumbar spine and femoral neck bone mineral density in postmenopausal women: a meta-analysis of randomized controlled trials

    Directory of Open Access Journals (Sweden)

    Kelley George A

    2012-09-01

    Full Text Available Abstract Background Low bone mineral density (BMD and subsequent fractures are a major public health problem in postmenopausal women. The purpose of this study was to use the aggregate data meta-analytic approach to examine the effects of ground (for example, walking and/or joint reaction (for example, strength training exercise on femoral neck (FN and lumbar spine (LS BMD in postmenopausal women. Methods The a priori inclusion criteria were: (1 randomized controlled trials, (2 exercise intervention???24?weeks, (3 comparative control group, (4 postmenopausal women, (5 participants not regularly active, i.e., less than 150?minutes of moderate intensity (3.0 to 5.9 metabolic equivalents weight bearing endurance activity per week, less than 75?minutes of vigorous intensity (> 6.0 metabolic equivalents weight bearing endurance activity per week, resistance training g was calculated for each FN and LS BMD result and pooled using random-effects models. Z-score alpha values, 95%confidence intervals (CI and number-needed-to-treat (NNT were calculated for pooled results. Heterogeneity was examined using Q and I2. Mixed-effects ANOVA and simple meta-regression were used to examine changes in FN and LS BMD according to selected categorical and continuous variables. Statistical significance was set at an alpha value ?0.05 and a trend at >0.05 to???0.10. Results Small, statistically significant exercise minus control group improvements were found for both FN (28?g’s, 1632 participants, g?=?0.288, 95% CI?=?0.102, 0.474, p?=?0.002, Q?=?90.5, p?I2?=?70.1%, NNT?=?6 and LS (28?g’s, 1504 participants, g?=?0.179, 95% CI?=??0.003, 0.361, p?=?0.05, Q?=?77.7, p?I2?=?65.3%, NNT?=?6 BMD. Clinically, it was estimated that the overall changes in FN and LS would reduce the 20-year relative risk of osteoporotic fracture at any site by approximately 11% and 10%, respectively. None of the mixed-effects ANOVA analyses were statistically significant. Statistically significant, or a trend for statistically significant, associations were observed for changes in FN and LS BMD and 20 different predictors. Conclusions The overall findings suggest that exercise may result in clinically relevant benefits to FN and LS BMD in postmenopausal women. Several of the observed associations appear worthy of further investigation in well-designed randomized controlled trials.

  19. Relação entre a mobilidade do tornozelo e pé e a magnitude da força vertical de reação do solo Relationship between ankle and foot mobility and the magnitude of the vertical ground reaction force

    Directory of Open Access Journals (Sweden)

    DL Vianna

    2006-09-01

    Full Text Available OBJETIVO: Verificar a relação entre a mobilidade do tornozelo e do pé, e o pico da força vertical de reação do solo, considerada como porcentagem do peso corporal, gerada durante a fase de apoio da marcha. MÉTODOS: foram estudados pés normais do lado direito e esquerdo de 15 homens com 22,1±2,7 anos (19-28 e 15 mulheres 24,20±5,24 anos (19-34. Os parâmetros de exclusão foram: deformidades nos pés, doenças ou traumas, que pudessem acometer o sistema musculoesquelético e a marcha. A mobilidade do tornozelo e dos pés foi obtida através da goniometria da flexão plantar, dorsiflexão, extensão do hálux e extensão dos dedos, o pico da força vertical de reação do solo FRS, foi obtido pela baropodometria computadorizada do sistema FSCAN R. A correlação entre ambas foi feita pelo teste estatístico de Spearman. RESULTADOS: os indivíduos do grupo masculino apresentaram menores valores de mobilidade, e maiores valores do pico da força vertical de reação do solo, quando comparados com o grupo feminino. Não houve diferença entre os pés direito e esquerdo. No sexo feminino foi encontrada correlação negativa estatisticamente significante entre os valores da flexão plantar e a força vertical, e entre os valores da extensão dos dedos e a foça vertical. No sexo masculino, houve correlação negativa estatisticamente significante entre os valores da dorsiflexão e a força vertical. Entre os demais valores não foi encontrada correlação significante. CONCLUSÃO: Há relação entre a mobilidade e a força vertical gerada durante a marcha.OBJECTIVE: To investigate the relationship between ankle and foot mobility and the peak of the vertical ground reaction force, as a percentage of body weight, generated during the gait stance phase. METHOD: Fifteen men with mean age of 22.1 ± 2.7 years (range: 19-28 and fifteen women with mean age of 24.20 ± 5.24 years (range: 19-34 with normal feet were studied. The exclusion criteria were foot deformities or a history of trauma or diseases that might have harmed both the musculoskeletal system and gait pattern. The ankle and foot mobility was obtained by means of goniometry on the plantar flexion, dorsiflexion, hallux extension and toe extension. The peak of the vertical ground reaction force was obtained by baropodometry using the FSCAN TM system. The Spearman statistical test was used to identify correlations. RESULTS: Males presented lower mobility values and higher peak values for the vertical ground reaction force, in comparison with females. There was no difference between the right and left foot. For females, there were statistically significant negative correlations between the values for plantar flexion and vertical force, and between the values for toe extension and vertical force. For males, there were statistically significant negative correlations between the values for dorsiflexion and vertical force. Among the remaining values, no significant correlation was found. CONCLUSION: There was a relationship between mobility and the vertical force generated during gait.

  20. Relação entre a mobilidade do tornozelo e pé e a magnitude da força vertical de reação do solo / Relationship between ankle and foot mobility and the magnitude of the vertical ground reaction force

    Scientific Electronic Library Online (English)

    DL, Vianna; JMD, Greve.

    2006-09-01

    Full Text Available OBJETIVO: Verificar a relação entre a mobilidade do tornozelo e do pé, e o pico da força vertical de reação do solo, considerada como porcentagem do peso corporal, gerada durante a fase de apoio da marcha. MÉTODOS: foram estudados pés normais do lado direito e esquerdo de 15 homens com 22,1±2,7 anos [...] (19-28) e 15 mulheres 24,20±5,24 anos (19-34). Os parâmetros de exclusão foram: deformidades nos pés, doenças ou traumas, que pudessem acometer o sistema musculoesquelético e a marcha. A mobilidade do tornozelo e dos pés foi obtida através da goniometria da flexão plantar, dorsiflexão, extensão do hálux e extensão dos dedos, o pico da força vertical de reação do solo FRS, foi obtido pela baropodometria computadorizada do sistema FSCAN R. A correlação entre ambas foi feita pelo teste estatístico de Spearman. RESULTADOS: os indivíduos do grupo masculino apresentaram menores valores de mobilidade, e maiores valores do pico da força vertical de reação do solo, quando comparados com o grupo feminino. Não houve diferença entre os pés direito e esquerdo. No sexo feminino foi encontrada correlação negativa estatisticamente significante entre os valores da flexão plantar e a força vertical, e entre os valores da extensão dos dedos e a foça vertical. No sexo masculino, houve correlação negativa estatisticamente significante entre os valores da dorsiflexão e a força vertical. Entre os demais valores não foi encontrada correlação significante. CONCLUSÃO: Há relação entre a mobilidade e a força vertical gerada durante a marcha. Abstract in english OBJECTIVE: To investigate the relationship between ankle and foot mobility and the peak of the vertical ground reaction force, as a percentage of body weight, generated during the gait stance phase. METHOD: Fifteen men with mean age of 22.1 ± 2.7 years (range: 19-28) and fifteen women with mean age [...] of 24.20 ± 5.24 years (range: 19-34) with normal feet were studied. The exclusion criteria were foot deformities or a history of trauma or diseases that might have harmed both the musculoskeletal system and gait pattern. The ankle and foot mobility was obtained by means of goniometry on the plantar flexion, dorsiflexion, hallux extension and toe extension. The peak of the vertical ground reaction force was obtained by baropodometry using the FSCAN TM system. The Spearman statistical test was used to identify correlations. RESULTS: Males presented lower mobility values and higher peak values for the vertical ground reaction force, in comparison with females. There was no difference between the right and left foot. For females, there were statistically significant negative correlations between the values for plantar flexion and vertical force, and between the values for toe extension and vertical force. For males, there were statistically significant negative correlations between the values for dorsiflexion and vertical force. Among the remaining values, no significant correlation was found. CONCLUSION: There was a relationship between mobility and the vertical force generated during gait.

  1. A influência do uso acumulado de calçados de corrida sobre a força de reação do solo e as respostas de pressão plantar / The influence of running shoes cumulative usage on the ground reaction forces and plantar pressure responses

    Scientific Electronic Library Online (English)

    Roberto, Bianco; Ana Paula da Silva, Azevedo; Carina Helena Wasem, Fraga; Fernanda Michelone, Acquesta; Luis, Mochizuki; Alberto Carlos, Amadio; Júlio Cerca, Serrão.

    2011-12-01

    Full Text Available Acredita-se que a eficiência do calçado seja afetada pelo uso prolongado, mas as alterações biomecânicas ainda não estão bem compreendidas. O objetivo deste estudo é analisar a influência do uso de calçados de corrida na força de reação do solo e os parâmetros de pressão plantar. Três corredores do [...] sexo masculino receberam quatro calçados de corrida para usarem em suas sessões de treinamento. O Sistema Gaitway e o Sistema de F-scan foram usados para registrar a força de reação do solo e parâmetros pressão plantar em diferentes regiões do pé. As coletas ocorreram em quatro momentos: novo e 100, 200 e 300 km de uso. O primeiro pico diminuiu da condição novo para os 300 km de uso (p Abstract in english The prolonged use of a running shoe is thought to affect the efficiency of its impact attenuation properties. However, its effect over biomechanical variables has yet not been well understood. The aim of this study was to examine the influence of running shoe usage on ground reaction force and plant [...] ar pressure parameters. Three male runners received four running shoes each to use at their training sessions. The Gaitway System was used to register the vertical component of the ground reaction force, whereas the contact area and peak plantar pressure at different regions of the foot were assessed via the the F-scan System. Data collection occurred at baseline (when the shoes were new - New) and after 100, 200 and 300km of use. The first peak decreased significantly from New to 300km (p

  2. Ground reaction force and electromyographic activity of transfemoral amputee gait: a case series http://dx.doi.org/10.5007/1980-0037.2013v15n1p16

    Directory of Open Access Journals (Sweden)

    Alberto Carlos Amadio

    2013-01-01

    Full Text Available Ground reaction forces (GRF and electromyographic activity form a part of the descriptive data that characterise the biomechanics of gait. The research of these parameters is important in establishing gait training and understanding the impact of amputation and prosthetic components on movement during the act of walking. Therefore, this case series describes the GRF and electromyographic activity in the gait of transfemoral amputees. A force plate was used to measure GRF, and an electromyographic system monitored the vastus lateralis, biceps femoris, tibialis anterior, and gastrocnemius lateralis muscles of the non-amputated leg. The average vertical and anteroposterior GRF time-curves, average electromyographic activity, and descriptor variables were then analysed. We observed decreases in vertical and anteroposterior GRF magnitudes as well as in anteroposterior GRF descriptor variables during the propulsive phase in the amputated leg. There were increases in phasic muscle activity and co-activation in the non-amputated leg. We concluded that, during walking, the unilateral transfemoral amputees (who were analysed in this case series developed lower GRF in the amputated limb and a longer period of electromyographic activity in the non-amputated limb.

  3. Saddle pressure distributions of three saddles used for Icelandic horses and their effects on ground reaction forces, limb movements and rider positions at walk and tölt.

    Science.gov (United States)

    Ramseier, Lea C; Waldern, Nina M; Wiestner, Thomas; Geser-von Peinen, Katja; Weishaupt, Michael A

    2013-12-01

    Icelandic horse riding practices aim to place the rider further caudally on the horse's back than in English riding, claiming that a weight shift toward the hindquarters improves the quality of the tölt (e.g. giving the shoulder more freedom to move). This study compared saddle pressure patterns and the effects on limb kinetics and kinematics of three saddles: an Icelandic saddle (S(Icel), lowest point of seat in the hind part of the saddle), a treeless saddle cushion (S(Cush)) and a dressage-style saddle (S(Dres)). Twelve Icelandic horses were ridden with S(Icel), S(Cush) and S(Dres) on an instrumented treadmill at walk and tölt. Saddle pressure, limb forces and kinematics were recorded simultaneously. With S(Cush), pressure was highest under the front part of the saddle, whereas the saddles with trees had more pressure under the hind area. The saddles had no influence on the motion patterns of the limbs. The slight weight shift to the rear with S(Cush) and S(Icel) may be explained by the more caudal position of the rider relative to the horse's back. PMID:24239262

  4. Ground reaction force and electromyographic activity of transfemoral amputee gait: a case series / Força de Reação do Solo e atividade eletromiográfica da marcha de amputados transfemorais: uma série de casos

    Scientific Electronic Library Online (English)

    Alex Sandra Oliveira de, Cerqueira; Edward Yuji, Yamaguti; Luis, Mochizuki; Alberto Carlos, Amadio; Júlio Cerca, Serrão.

    2013-02-01

    Full Text Available O comportamento da Força de Reação do Solo (FRS) e a atividade eletromiográfica formam uma parte dos dados que caracterizam a biomecânica da marcha. O estudo destes parâmetros é importante para a recuperação da locomoção e para compreensão do impacto da amputação e dos componentes protéticos nos mov [...] imentos desenvolvidos no andar. Portanto, esta série de casos tem como objetivo descrever a atividade eletromiográfica e a FRS de amputados transfemorais. Para mensurar a FRS, foi utilizada uma plataforma de força e um sistema de eletromiografia monitorou os músculos vasto lateral, bíceps femoral, tibial anterior e gastrocnêmio lateral da perna não-amputada. As médias das componentes vertical e ânteroposterior da FRS, a atividade eletromiográfica e variáveis descritivas foram analisadas. Foi observado uma diminuição da magnitude da FRS vertical e ânteroposterior e das variáveis descritivas da componente ânteroposterior da FRS durante a fase de propulsão na perna amputada. Houve aumento na atividade fásica muscular e co-ativação na perna não-amputada. Pode-se concluir que os amputados transfemorais unilaterais analisados nesta série de casos desenvolveram menor FRS na perna amputada e longos períodos de atividade eletromiográfica na perna não amputada durante a marcha. Abstract in english Ground reaction forces (GRF) and electromyographic activity form a part of the descriptive data that characterise the biomechanics of gait. The research of these parameters is important in establishing gait training and understanding the impact of amputation and prosthetic components on movement dur [...] ing the act of walking. Therefore, this case series describes the GRF and electromyographic activity in the gait of transfemoral amputees. A force plate was used to measure GRF, and an electromyographic system monitored the vastus lateralis, biceps femoris, tibialis anterior, and gastrocnemius lateralis muscles of the non-amputated leg. The average vertical and anteroposterior GRF time-curves, average electromyographic activity, and descriptor variables were then analysed. We observed decreases in vertical and anteroposterior GRF magnitudes as well as in anteroposterior GRF descriptor variables during the propulsive phase in the amputated leg. There were increases in phasic muscle activity and co-activation in the non-amputated leg. We concluded that, during walking, the unilateral transfemoral amputees (who were analysed in this case series) developed lower GRF in the amputated limb and a longer period of electromyographic activity in the non-amputated limb.

  5. Ground reaction force in basketball cutting maneuvers with and without ankle bracing and taping / Análise da força de reação do solo durante o cutting no basquetebol com e sem o uso de implementos no tornozelo

    Scientific Electronic Library Online (English)

    Isabel de Camargo Neves, Sacco; Henrique Yuji, Takahasi; Eneida Yuri, Suda; Linamara Rizzo, Battistella; Cristianne Akie, Kavamoto; José Augusto Fernandes, Lopes; Jeane Cintra Peixoto de, Vasconcelos.

    Full Text Available CONTEXTO E OBJETIVO: A lesão mais comum no basquetebol é a entorse de tornozelo. Assim, os atletas freqüentemente utilizam suportes externos como medidas profiláticas. O objetivo deste estudo é avaliar as respostas da força de reação do solo (FRS) durante a execução do movimento de cutting do basque [...] tebol com e sem acessórios de tornozelo. TIPO DE ESTUDO E LOCAL: Estudo comparativo. Delineamento experimental de grupo único com medidas repetidas; Divisão de Medicina de Reabilitação, Hospital das Clínicas, Faculdade de Medicina da Universidade de São Paulo, Brasil. MÉTODOS: Foram colhidas as forças vertical (Fy) e médio-lateral (Fz) em três condições (bandagem, Aircast e calçado esportivo) e analisados os picos de força e de propulsão no contato com o solo (Fymax1, Fzmax1, Fymax2 e Fzmax2), o gradiente de crescimento (pico/tempo) (GC Fymax1, GC Fzmax1, GC Fymax2 e GC Fzmax2) e o impulso após o contato. RESULTADOS: Os acessórios reduziram significativamente Fymax2 e GC Fymax2. GC FZmax1 foi maior na situação com tênis quando comparado com bandagem. No momento do impacto, a bandagem aumentou a Fy em relação ao calçado, mas em um intervalo de tempo maior, não aumentando a carga articular. Fz atingiu um pico em menor tempo, podendo gerar maior carga eversora/inversora. O Aircast exerceu um melhor efeito de absorção de impacto, pois gera menor Fy em um maior intervalo de tempo. CONCLUSÕES: Apesar do uso freqüente deste tipo de recurso pelos atletas, seu mecanismo de ação ainda é confuso. Mais estudos são necessários para esclarecer seus efeitos nas atividades esportivas a longo prazo. Abstract in english CONTEXT AND OBJECTIVE: In basketball, the most common injuries are ankle sprains. For this reason, players frequently use external ankle devices or taping as prophylactic and rehabilitation measures. The purpose of this study was to evaluate ground reaction force (GRF) responses in basketball player [...] s while performing typical cutting maneuvers with and without ankle bracing and ankle taping. DESIGN AND SETTING: Comparative study with experimental design of single-group repeated measurements, at Medical Rehabilitation Division, Hospital das Clínicas, Faculdade de Medicina, Universidade de São Paulo. METHODS: Vertical (Fy) and medial-lateral (Fz) GRF measurements were made under three conditions (taping, Aircast-type orthosis and basketball shoes alone), with analysis of peak forces at foot contact (Fymax1, Fzmax1, Fymax2 and Fzmax2), growth gradient (peak/time) (GG Fymax1, GG Fzmax1, GG Fymax2 and GG Fzmax2) and impulse after foot contact. RESULTS: Bracing significantly reduced Fymax2 and GG Fymax2. GG Fzmax1 was significantly higher for the sport shoe condition than for the taping condition. Taping increased Fy in relation to the sport shoe at foot contact, but over a longer time interval, without increasing excessive ankle loading. Fz reached a peak in less time, which might generate greater inversion/eversion loading on a player's foot. The Aircast exerted better shock-absorbing effect than did the other two conditions, since it generated less vertical force over longer time intervals and smaller medial-lateral forces in relation to taping. CONCLUSIONS: Ankle bracing and ankle taping action mechanisms are still unclear and therefore should be carefully prescribed. More studies are needed to clarify taping and bracing effects on sporting activities.

  6. Relationships between ground reaction impulse and sprint acceleration performance in team sport athletes.

    Science.gov (United States)

    Kawamori, Naoki; Nosaka, Kazunori; Newton, Robert U

    2013-03-01

    Large horizontal acceleration in short sprints is a critical performance parameter for many team sport athletes. It is often stated that producing large horizontal impulse at each ground contact is essential for high short sprint performance, but the optimal pattern of horizontal and vertical impulses is not well understood, especially when the sprints are initiated from a standing start. This study was an investigation of the relationships between ground reaction impulses and sprint acceleration performance from a standing start in team sport athletes. Thirty physically active young men with team sport background performed 10-m sprint from a standing start, whereas sprint time and ground reaction forces were recorded during the first ground contact and at 8 m from the start. Associations between sprint time and ground reaction impulses (normalized to body mass) were determined by a Pearson's correlation coefficient (r) analysis. The 10-m sprint time was significantly (p < 0.01) correlated with net horizontal impulse (r = -0.52) and propulsive impulse (r = -0.66) measured at 8 m from the start. No significant correlations were found between sprint time and impulses recorded during the first ground contact after the start. These results suggest that applying ground reaction impulse in a more horizontal direction is important for sprint acceleration from a standing start. This is consistent with the hypothesis of training to increase net horizontal impulse production using sled towing or using elastic resistance devices, which needs to be validated by future longitudinal training studies. PMID:22531618

  7. Ground reaction curve based upon block theory

    Energy Technology Data Exchange (ETDEWEB)

    Yow, J.L. Jr.; Goodman, R.E.

    1985-09-01

    Discontinuities in a rock mass can intersect an excavation surface to form discrete blocks (keyblocks) which can be unstable. Once a potentially unstable block is identified, the forces affecting it can be calculated to assess its stability. The normal and shear stresses on each block face before displacement are calculated using elastic theory and are modified in a nonlinear way by discontinuity deformations as the keyblock displaces. The stresses are summed into resultant forces to evaluate block stability. Since the resultant forces change with displacement, successive increments of block movement are examined to see whether the block ultimately becomes stable or fails. Two-dimensional (2D) and three-dimensional (3D) analytic models for the stability of simple pyramidal keyblocks were evaluated. Calculated stability is greater for 3D analyses than for 2D analyses. Calculated keyblock stability increases with larger in situ stress magnitudes, larger lateral stress ratios, and larger shear strengths. Discontinuity stiffness controls blocks displacement more strongly than it does stability itself. Large keyblocks are less stable than small ones, and stability increases as blocks become more slender.

  8. Ground reaction curve based upon block theory

    International Nuclear Information System (INIS)

    Discontinuities in a rock mass can intersect an excavation surface to form discrete blocks (keyblocks) which can be unstable. Once a potentially unstable block is identified, the forces affecting it can be calculated to assess its stability. The normal and shear stresses on each block face before displacement are calculated using elastic theory and are modified in a nonlinear way by discontinuity deformations as the keyblock displaces. The stresses are summed into resultant forces to evaluate block stability. Since the resultant forces change with displacement, successive increments of block movement are examined to see whether the block ultimately becomes stable or fails. Two-dimensional (2D) and three-dimensional (3D) analytic models for the stability of simple pyramidal keyblocks were evaluated. Calculated stability is greater for 3D analyses than for 2D analyses. Calculated keyblock stability increases with larger in situ stress magnitudes, larger lateral stress ratios, and larger shear strengths. Discontinuity stiffness controls blocks displacement more strongly than it does stability itself. Large keyblocks are less stable than small ones, and stability increases as blocks become more slender

  9. Acute fatigue effects on ground reaction force of lower limbs during countermovement jumps / Estudio del efecto de la fatiga aguda en la fuerza del miembros inferiores durante saltos con contramovimiento / Estudo do efeito agudo da fadiga na força de membros inferiores durante saltos com contramovimento

    Scientific Electronic Library Online (English)

    Carlos Gabriel, Fábrica; Paula V., González; Jefferson Fagundes, Loss.

    2013-12-01

    Full Text Available Parâmetros associados com o desempenho do salto contramovimento foram identificados a partir de registros da força vertical em condições de fadiga e não fadiga. Quatorze variáveis foram definidas dividindo a força de reação vertical do solo em valores negativos e positivos de trabalho externo e o te [...] mpo em que os valores de força vertical foi menor e maior do que o peso corporal do indivíduo. As variações dos parâmetros foram avaliadas considerando a relação entre conjunto de elementos contráteis e elásticos nos membros inferiores. Determinou-se que o desempenho é baseado na otimização do impulso e não em um valor instantâneo da força; o tempo em que a força de reação do solo foi menor do que o peso corporal e o tempo de trabalho externo negativo são mais baixos sob fadiga. Os resultados sugerem que durante a fadiga há uma menor contribuição da energia elástica e do estado ativo de forma global, mas a participação de elementos contráteis poderia compensar parcialmente a queda de desempenho. Abstract in spanish Se identificaron parámetros asociados con el desempeño de saltos con contramovimiento a partir de registros de fuerza vertical en condiciones de fatiga y no fatiga. Catorce variables fueron definidas dividiendo la componente vertical de la curva de fuerza de reacción del suelo en valores negativos y [...] positivos de trabajo externo y tiempo en que los valores de fuerza resultaron menores o mayores que el valor del peso del individuo. Las variaciones de los parámetros fueron evaluadas considerando la relación entre el conjunto de elementos contráctiles y elásticos en los miembros inferiores. Se determinó que el desempeño está basado en la optimización del impulso y no en un valor instantáneo de fuerza; el tiempo en que la fuerza de reacción del suelo fue menor que el peso corporal y el tiempo de trabajo externo negativo resultaron más bajos en fatiga. Los resultados sugieren que durante la fatiga hay una menor contribución de la energía elástica y del estado activo de forma global, pero la participación de elementos contráctiles podría compensar parcialmente la caída en el desempeño. Abstract in english Parameters associated with the performance of countermovement jumps were identified from vertical ground reaction force recordings during fatigue and resting conditions. Fourteen variables were defined, dividing the vertical ground reaction force into negative and positive external working times and [...] times in which the vertical ground reaction force values were lower and higher than the participant's body weight. We attempted to explain parameter variations by considering the relationship between the set of contractile and elastic components of the lower limbs. We determined that jumping performance is based on impulsion optimization and not on instantaneous ground reaction force value: the time in which the ground reaction force was lower than the body weight, and negative external work time was lower under fatigue. The results suggest that, during fatigue, there is less contribution from elastic energy and from overall active state. However, the participation of contractile elements could partially compensate for the worsening of jumping performance.

  10. Ground state octupole correlation energy with effective forces

    Science.gov (United States)

    Robledo, L. M.

    2015-05-01

    The ground state octupole correlation energy is computed with the D1M variant of the Gogny force in different theoretical frameworks and analyzed in detail. First I consider the correlation energy gained at the mean field level by breaking reflection symmetry. Next I consider the energy gain coming from symmetry (parity) restoration and finally I analyze the ground state correlation energy after configuration mixing with axially symmetric octupole states. The impact of the latter on theoretical binding energies indicates that octupole correlations do not affect in a significant way the trend and systematic of binding energies and therefore can not improve the performance of theoretical models in this respect. In particular, the too-large ‘shell gaps’ predicted by self-consistent mean field models and relevant in astrophysics scenarios are not altered by the octupole correlations.

  11. Forced vibration tests of a model foundation on rock ground

    International Nuclear Information System (INIS)

    The effect of the dynamic soil-structure interaction was investigated experimentally by forced vibration tests of a model foundation resting on rock surface. The experiment was carried out in 1985 at Tomari nuclear power plant site, Hokkaido, Japan. The model foundation was made of reinforced concrete of 14m*14m in plan and 5m thick and the total weight was 2352 ton. The ground was made of two layers whose interface was inclined by certain degree from north-west to south-east. The forced vibration tests were carried out mainly by an exciter of maximum 4 ton force. Micro-tremor and micro-earthquake were also observed. In this experiment such special attention was paid for obtaining good traction data beneath the foundation as accurate calibration of pressure gauges at the site and the use of auxiliary exciter with larger capacity. Simulations are carried out by wave propagation theory and FEM. Simulated results can reasonably explain the experimental results and the dynamic soil-structure interaction effects in various aspects. Resultant forces and moments evaluated by experimentally obtained tractions with approximated polynomial distribution are in good agreement with those evaluated by displacements

  12. Regulation of reaction forces during the golf swing.

    Science.gov (United States)

    McNitt-Gray, J L; Munaretto, J; Zaferiou, A; Requejo, P S; Flashner, H

    2013-06-01

    During the golf swing, the reaction forces applied at the feet control translation and rotation of the body-club system. In this study, we hypothesized that skilled players using a 6-iron would regulate shot distance by scaling the magnitude of the resultant horizontal reaction force applied to the each foot with minimal modifications in force direction. Skilled players (n = 12) hit golf balls using a 6-iron. Shot distance was varied by hitting the ball as they would normally and when reducing shot distance using the same club. During each swing, reaction forces were measured using dual force plates (1200 Hz) and three-dimensional kinematics were simultaneously captured (110 Hz). The results indicate that, on average, the peak resultant horizontal reaction forces of the target leg were significantly less than normal (5%, p swing were consistent within player across shot conditions. Regulation of force magnitude with minimal modification in force direction is expected to provide advantages from muscle activation, coordination, and performance points of view. PMID:23898685

  13. Tensor forces and the ground-state structure of nuclei.

    Science.gov (United States)

    Schiavilla, R; Wiringa, R B; Pieper, Steven C; Carlson, J

    2007-03-30

    Two-nucleon momentum distributions are calculated for the ground states of nuclei with mass number Anucleon potentials. The momentum distribution of np pairs is found to be much larger than that of pp pairs for values of the relative momentum in the range (300-600) MeV/c and vanishing total momentum. This order of magnitude difference is seen in all nuclei considered and has a universal character originating from the tensor components present in any realistic nucleon-nucleon potential. The correlations induced by the tensor force strongly influence the structure of np pairs, which are predominantly in deuteronlike states, while they are ineffective for pp pairs, which are mostly in 1S0 states. These features should be easily observable in two-nucleon knockout processes, such as A(e,e'np) and A(e,e'pp). PMID:17501194

  14. Government Applications Task Force ground truth study of WAG 4

    International Nuclear Information System (INIS)

    This report documents the Government Applications Task Force (GATF) Buried Waste Project. The project was initiated as a field investigation and verification of the 1994 Strategic Environmental Research and Development Program's (SERDP) Buried Waste Identification Project results. The GATF project team included staff from three US Department of Energy (DOE) Laboratories [Oak Ridge National Laboratory (ORNL), Los Alamos National Laboratory (LANL), and the Savannah River Technology Center (SRTC)] and from the National Exploitation Laboratory. Similar studies were conducted at each of the three DOE laboratories to demonstrate the effective use of remote sensing technologies. The three locations were selected to assess differences in buried waste signatures under various environmental conditions (i.e., climate, terrain, precipitation, geology, etc.). After a brief background discussion of the SERDP Project, this report documents the field investigation (ground truth) results from the 1994--1995 GATF Buried Waste Study at ORNL's Waste Area Grouping (WAG) 4. Figures for this report are located in Appendix A

  15. Radiation reaction force and unification of electromagnetic and gravitational fields

    International Nuclear Information System (INIS)

    A unified theory of electromagnetic and gravitational fields should modify classical electrodynamics such that the radiation reaction force is accounted for. The analysis leads to a five-dimensional unified theory of five variables. The theory is supported by showing that, for the case of a charged particle moving in a constant magnetic field, the radiation reaction force is indeed included. Moreover, this example shows explicitly that physical changes are associated with the fifth variable. Thus, the notion of a physical five-dimensional space should be seriously taken into consideration

  16. Effects of ground plane topology on vortex-ground interactions in a forced impinging jet

    Science.gov (United States)

    Geiser, Jayson; Corfman, Kyle; Kiger, Ken

    2011-11-01

    The phenomenon of a three-dimensionally unstable vortex-ground interaction is studied, motivated by the problem of sediment suspension by vortex-wall interactions from landing rotorcraft. In the current work, the downwash of a rotorcraft is simplified using a prototype flow consisting of an acoustically forced impinging jet. The goal of the current investigation is to quantify the effects of disturbances to the ground-plane boundary layer on the three-dimensional development of the vortex ring as it interacts with the ground plane. A small radial fence is employed to perturb the natural evolution of the secondary vortex, which typically exhibits azimuthal instabilities as it is wrapped around the primary vortex. The fence is observed to localize and intensify the azimuthal development, dramatically altering the mean flow in this region and generating corresponding azimuthal variations in the turbulent near-wall stresses. Multi-plane ensemble-averaged stereo PIV is employed to obtain volumetric, phase averaged data sets that are subjected to a triple decomposition to fully quantify turbulence effects. The effects of the radial fence are examined at both a high and low Reynolds number flows (Re = ?/? = 50,000 and 10,000, respectively), and the data is analyzed in the context of structures leading to significant sediment mobilization.

  17. A thermodynamic force generated by chemical gradient and adsorption reaction

    CERN Document Server

    Sugawara, Takeshi

    2009-01-01

    Biological units such as macromolecules, organelles, and cells are directed to a proper location under gradients of relevant chemicals. By considering a macroscopic element that has binding sites for a chemical adsorption reaction to occur on its surface, we show the existence of a thermodynamic force that is generated by the gradient and exerted on the element. By assuming local equilibrium and adopting the grand potential from thermodynamics, we derive a formula for such a thermodynamic force, which depends on the chemical potential gradient and Langmuir isotherm. The conditions under which the formula can be applied are demonstrated to hold in intracellular reactions. The role of the force in the partitioning of bacterial chromosome/plasmid during cell division is discussed.

  18. ["Forced mouth opening reaction" associated with corticobasal degeneration].

    Science.gov (United States)

    Ohkawa, S; Yamasaki, H; Yoshida, T; Ohsumi, Y; Tabuchi, M

    1997-04-01

    Corticobasal degeneration (CBD) is a slowly progressive disorder characterized by an asymmetrical akinetic-rigid syndrome, supranuclear ophthalmoplegia, dystonia, often accompanied by involuntary movements, particularly myoclonus, and associated with lateralized cortical signs such as alien limb behavior and apraxia. Computerized tomography demonstrates asymmetrical frontoparietal cortical atrophy in the later stages of the illness. Neuropathological examination reveals neuronal loss, gliosis and swollen achromatic neurons within the frontal and temporal cortices, and the substantia nigra. We discuss here a unique phenomenon not described so far in three patients with clinical features of CBD, one with subsequent autopsy observations. When awake, they all showed a common behavior, their mouth opened constantly and immediately, when a tongue-depresser was approached in front of it by the examiner. In two of them, their mouth also opened when its corner was stroked by a tongue-depressor. They could not control these phenomena at all, even they were asked not to open their mouth. We would like to call these phenomena "forced mouth opening reactions" because they were uncontrollable voluntarily. They may be divided into two groups, i.e. visual and tactile "forced mouth opening reactions". In all the patients the neurological, neuro-imaging and neuropathological data showed that the frontal lobes were damaged. Additionally, they had some frontal lobe release signs such as forced grasping, forced groping, or alien limb sign. We would like to apply the mechanism for these release signs to the "forced mouth opening reactions". Thus, we speculate that the frontal lobe contains a higher motor control mechanism for normal mouth opening movement, and the "forced mouth opening reactions" result from impairment of this control. PMID:9248334

  19. Comparison of the electron-spin force and radiation reaction force

    Science.gov (United States)

    Mahajan, Swadesh M.; Asenjo, Felipe A.; Hazeltine, Richard D.

    2015-02-01

    It is shown that the forces that originate from the electron-spin interacting with the electromagnetic field can play, along with the Lorentz force, a fundamentally important role in determining the electron motion in a high energy density plasma embedded in strong high-frequency radiation, a situation that pertains to both laser-produced and astrophysical systems. These forces, for instance, dominate the standard radiation reaction force as long as there is a `sufficiently' strong ambient magnetic field for affecting spin alignment. The inclusion of spin forces in any advanced modelling of electron dynamics pertaining to high energy density systems (for instance in particle-in-cell codes), therefore, is a must.

  20. Quantum Vacuum and Inertial Reaction Force in Nonrelativistic QED

    CERN Document Server

    Sunahata, Hiroki; Haisch, Bernard

    2013-01-01

    The possible connection between the electromagnetic zero-point field (ZPF) and the inertia reaction force was first pointed out by Haisch, Rueda, and Puthoff (Phys. Rev. A, 49, 678, 1994), and then by Rueda and Haisch following a totally different and more satisfactory approach (Found. Phys., 28, 1057, 1998; Phys. Letters A, 240, 115, 1998; Annalen der Physik, 10 (5), 393, 2001). In the present paper, the approach taken by Rueda and Haisch will be followed, but the analysis will be done within a formulation that uses nonrelativistic quantum electrodynamics with the creation and annihilation operators rather than the approach of Rueda and Haisch using stochastic electrodynamics. We analyze the interaction between the zero-point field and an object under hyperbolic motion (constant proper acceleration), and find that there arises a reaction force which is proportional in magnitude, and opposite in direction, to the acceleration. This is suggestive of what we know as inertia. We also point out that the equivalen...

  1. Forced vibration tests of a model foundation on rock ground

    International Nuclear Information System (INIS)

    The displacement and tractions are experimentally obtained by forced vibration tests of a model foundation to investigate the effects of the dynamic soil-structure interaction. Impedance functions and displacements are well simulated by wave propagation theory and quasi-3-dimensional FEM including unisotropy in macroscopic sense. Tractions are also obtained with high quality so that the integrated values such as resultant forces and moments are in good agreement with those evaluated by experimentally obtained displacements. (orig.)

  2. Fore-aft ground force adaptations to induced forelimb lameness in walking and trotting dogs.

    Science.gov (United States)

    Abdelhadi, Jalal; Wefstaedt, Patrick; Nolte, Ingo; Schilling, Nadja

    2012-01-01

    Animals alter their locomotor mechanics to adapt to a loss of limb function. To better understand their compensatory mechanisms, this study evaluated the changes in the fore-aft ground forces to forelimb lameness and tested the hypothesis that dogs unload the affected limb by producing a nose-up pitching moment via the exertion of a net-propulsive force when the lame limb is on the ground. Seven healthy Beagles walked and trotted at steady speed on an instrumented treadmill while horizontal force data were collected before and after a moderate lameness was induced. Peak, mean and summed braking and propulsive forces as well as the duration each force was exerted and the time to reach maximum force were evaluated for both the sound and the lame condition. Compared with the sound condition, a net-propulsive force was produced by the lame diagonal limbs due to a reduced braking force in the affected forelimb and an increased propulsive force in the contralateral hindlimb when the dogs walked and trotted. To regain pitch stability and ensure steady speed for a given locomotor cycle, the dogs produced a net-braking force when the sound diagonal limbs were on the ground by exerting greater braking forces in both limbs during walking and additionally reducing the propulsive force in the hindlimb during trotting. Consistent with the proposed mechanism, dogs maximize their double support phases when walking. Likely associated with the fore-aft force adaptations to lameness are changes in muscle recruitment that potentially result in short- and long-term effects on the limb and trunk muscles. PMID:23300614

  3. Tensor Forces and the Ground-State Structure of Nuclei

    OpenAIRE

    Schiavilla, R.; Wiringa, R. B.; Pieper, Steven C.; Carlson, J.

    2006-01-01

    Two-nucleon momentum distributions are calculated for the ground states of nuclei with mass number $A\\leq 8$, using variational Monte Carlo wave functions derived from a realistic Hamiltonian with two- and three-nucleon potentials. The momentum distribution of $np$ pairs is found to be much larger than that of $pp$ pairs for values of the relative momentum in the range (300--600) MeV/c and vanishing total momentum. This order of magnitude difference is seen in all nuclei con...

  4. Forcing a countable structure to belong to the ground model

    OpenAIRE

    Kaplan, Itay; Shelah, Saharon

    2014-01-01

    Suppose that $P$ is a forcing notion, $L$ is a language (in $V$), $\\dot{\\tau}$ a $P$-name such that $P\\Vdash$ "$\\dot{\\tau}$ is a countable $L$-structure". In the product $P\\times P$, there are names $\\dot{\\tau_{1}},\\dot{\\tau_{2}}$ such that for any generic filter $G=G_{1}\\times G_{2}$ over $P\\times P$, $\\dot{\\tau}_{1}[G]=\\dot{\\tau}[G_{1}]$ and $\\dot{\\tau}_{2}[G]=\\dot{\\tau}[G_{2}]$. Zapletal asked whether or not $P \\times P \\Vdash \\dot{\\tau}_{1}\\cong\\dot{\\tau}_{2}$ implies th...

  5. Air Force Geophysics Laboratory portable PCM ground station

    Science.gov (United States)

    Shaw, H.; Lawrence, F. A.

    The present paper is concerned with the development of a portable Pulse-Code Modulation (PCM) telemetry station for the Air Force Geophysics Laboratory (AFGL). A system description is provided, taking into account the system equipment, the interface, the decommutator (DECOM) section of the interface, the direct memory access (DMA) section, and system specifications and capabilities. In the context of selecting between two conflicting philosophies regarding software, it was decided to favor a small scale specialized approach. Attention is given to the operating system, aspects of setting up the software, the application software, and questions of portability.

  6. Keyboard reaction force and finger flexor electromyograms during computer keyboard work.

    Science.gov (United States)

    Martin, B J; Armstrong, T J; Foulke, J A; Natarajan, S; Klinenberg, E; Serina, E; Rempel, D

    1996-12-01

    This study examines the relationship between forearm EMGs and keyboard reaction forces in 10 people during keyboard tasks performed at a comfortable speed. A linear fit of EMG force data for each person and finger was calculated during static fingertip loading. An average r2 of .71 was observed for forces below 50% of the maximal voluntary contraction (MVC). These regressions were used to characterize EMG data in force units during the typing task. Averaged peak reaction forces measured during typing ranged from 3.33 N (thumb) to 1.84 N (little finger), with an overall average of 2.54 N, which represents about 10% MVC and 5.4 times the key switch make force (0.47 N). Individual peak or mean finger forces obtained from EMG were greater (1.2 to 3.2 times) than force measurements; hence the range of r2 for EMG force was .10 to .46. A closer correspondence between EMG and peak force was obtained using EMG averaged across all fingers. For 5 of the participants the force computed from EMG was within +/-20% of the reaction force. For the other 5 participants forces were overestimated. For 9 participants the difference between EMG estimated force and the reaction force was less than 13% MVC. It is suggested that the difference between EMG and finger force partly results from the amount of muscle load not captured by the measured applied force. PMID:8976628

  7. Fore-Aft Ground Force Adaptations to Induced Forelimb Lameness in Walking and Trotting Dogs

    OpenAIRE

    Abdelhadi, Jalal; Wefstaedt, Patrick; Nolte, Ingo; Schilling, Nadja

    2012-01-01

    Animals alter their locomotor mechanics to adapt to a loss of limb function. To better understand their compensatory mechanisms, this study evaluated the changes in the fore-aft ground forces to forelimb lameness and tested the hypothesis that dogs unload the affected limb by producing a nose-up pitching moment via the exertion of a net-propulsive force when the lame limb is on the ground. Seven healthy Beagles walked and trotted at steady speed on an instrumented treadmill while horizontal f...

  8. Decrease of reaction force of metal gaskets just after initial tightening

    International Nuclear Information System (INIS)

    The decrease of reaction force of some metal gaskets inserted into the test flange at room temperature, 120 C(real cask temperature) and 200 C(accelerated condition) are measured. The reaction forces of metal gaskets in the room temperature have been almost not changed. The reaction force of 120 C and 200 C metal gaskets has decreased according to the temperature increase. After the temperature became stable, the decrease of the reaction force gradually proceeded, this decrease have been as same as previous studies. The bolts of transport and storage casks are usually tightened just after the loading of spent fuels, and then the temperature of metal gaskets at that time is almost the room temperature. The reaction forces of the metal gasket tightened at this condition would be decreased after the temperature increase due to the decay heat of spent fuels. It is confirmed that the loosening of the bolts might be happened if the tightening torque of bolts is not appropriate. It is easy to evaluate that the reaction forces of the metal gasket in storage condition according to Larson-Miller parameter or relaxation of the gasket material, but the decrease of the reaction forces of the metal gasket just after the loading is not able to evaluate by these method. It is necessary to evaluate the reaction forces according to plastic deformation property of the metal gaskets so as to fasten the gaskets safety

  9. The study of vertical ground reaction during walk of Czech women

    Directory of Open Access Journals (Sweden)

    Pavel Korvas

    2013-09-01

    Full Text Available The aim of this study was to find whether it is possible to explain different plantar loading during absorption and propulsive stages of stance in the observed persons by means of basic body indicators or time characteristics of gait. Fifty-one healthy women participated in the study; their age range was between 30 and 60 years of age. The women were divided into two groups according to whether they reached higher values of vertical ground reaction during absorption (group A, 8 women, 16 % or propulsive (group B, 43 women, 84 % stage of stance. Capacitive pressure insoles in the shoe were used (PedarX, Novel Munich. During laboratory survey each woman performed monitored natural walk. Three stances of each leg were assessed, always from between the third and eighth steps. Five parameters had been chosen for monitoring, three recording force characteristics of gait and two time parameters. Group A reached relative value of 121 % of BW during the first stage and 110 % of BW during the second one. Group B reached 105 % in the initial stage, and 117 % of BW in the other stage. A significant difference was found for F1 parameter between groups A and B, not for the second part of stage. Group A manifested shorter duration of both stages of stance (not significantly different from group B. The level of relationship between stance duration as well as its stages and force manifestations in both groups of women was very low (from r= 0.010 to 0.015. Only in group A, the weight of the women correlated with relative values of both F1 and F2 (r = - 0.795, r = - 0.625 resp..

  10. Spanwise Optimum Normal Force Distribution of a Hemi-Circular Wing-in-Ground

    Science.gov (United States)

    Yamamoto, Yuzo

    The aerodynamic characteristics of a hemi-circular wing-in-ground are studied analytically. The exact expression of a spanwise optimum normal force distribution and the minimum induced drag are obtained from Trefftz plane flow field analysis, where Söhngen’s inversion integral formula and the elliptic integrals and Jacobian elliptic functions are used. The minimum induced drag obtained in the present study is coincident with that of Mamada and Ando.

  11. Forces and pressures beneath the saddle during mounting from the ground and from a raised mounting platform.

    Science.gov (United States)

    Geutjens, C A; Clayton, H M; Kaiser, L J

    2008-03-01

    The objective was to use an electronic pressure mat to measure and compare forces and pressures of the saddle on a horse's back when riders mounted from the ground and with the aid of a mounting platform. Ten riders mounted a horse three times each from the ground and from a 35 cm high mounting platform in random order. Total force (summation of forces over all 256 sensors) was measured and compared at specific points on the force-time curve. Total force was usually highest as the rider's right leg was swinging upwards and was correlated with rider mass. When normalized to rider mass, total force and peak pressure were significantly higher when mounting from the ground than from a raised platform (Psaddle during mounting. PMID:17572121

  12. [Environmental investigation of ground water contamination at Wright-Patterson Air Force Base, Ohio

    International Nuclear Information System (INIS)

    The Phase I, Task 5, Focused Feasibility Study (FFS) has been prepared as part of the Environmental Investigation of Ground Water Contamination Project being conducted by Wright-Patterson Air Force Base (WPAFB). The primary objective of this FFS was to select a cost-effective method of preventing migration of contaminated ground water across the southwestern boundary of Area C of the Base. The FFS presented in this document is a portion of a much larger effort being conducted at WPAFB. The detailed analysis of alternatives for the extraction, treatment, and discharge of contaminated ground water migrating across the southwest boundary of Area C at WPAFB led to the selection of a preferred removal action alternative. Specifically, this alternative is that ground water be extracted utilizing a three well array pumping at a total of 400 to 800 gpm, removed water be treated via air stripping to achieve appropriate effluent concentrations, and treated water be discharged to the Mad River in accordance with a National Pollution Discharge Elimination System (NPDES) permit and other relevant permits

  13. Radiated power and radiation-reaction force: A derivation based on Fourier transforms

    International Nuclear Information System (INIS)

    On making use of the Fourier transforms, general formulas for the time-averaged radiated power and radiation-reaction force are obtained in terms of either the spectral distribution of the source current density or the source charge and current density at the retarded time. The former expressions are particularly suited for the derivation of the Lienard formula for the radiated power as well as the Abraham-Becker form of the radiation-reaction force for a pointlike charge. The procedure of getting instantaneous radiation quantities from the corresponding time-averaged ones is discussed critically and the Abraham-Lorentz force, obtained on the basis of the Heaviside-Feynman fields, is identified as the instantaneous radiation-reaction force

  14. Ground-state van der Waals forces in planar multilayer magnetodielectrics

    CERN Document Server

    Buhmann, S Y; Welsch, D G; Buhmann, Stefan Yoshi; Kampf, Thomas; Welsch, Dirk-Gunnar

    2005-01-01

    Within the frame of lowest-order perturbation theory, the van der Waals potential of a ground-state atom placed within an arbitrary dispersing and absorbing magnetodielectric multilayer system is given. Examples of an atom situated in front of a magnetodielectric plate or between two such plates are studied in detail. Special emphasis is placed on the competing attractive and repulsive force components associated with the electric and magnetic matter properties, respectively, and conditions for the formation of repulsive potential walls are given. Both numerical and analytical results are presented.

  15. (Environmental investigation of ground water contamination at Wright- Patterson Air Force Base, Ohio)

    Energy Technology Data Exchange (ETDEWEB)

    1991-10-01

    This Health and Safety Plan (HSP) was developed for the Environmental Investigation of Ground-water Contamination Investigation at Wright-Patterson Air Force Base near Dayton, Ohio, based on the projected scope of work for the Phase 1, Task 4 Field Investigation. The HSP describes hazards that may be encountered during the investigation, assesses the hazards, and indicates what type of personal protective equipment is to be used for each task performed. The HSP also addresses the medical monitoring program, decontamination procedures, air monitoring, training, site control, accident prevention, and emergency response.

  16. Foot Reaction Forces during Long Duration Space Flight

    Science.gov (United States)

    Gopalakrishnan, R.; Rice, A. J.; Genc, K. O.; Maender, C. C.; Kuklis, M. M.; Humphreys, B.; Cavanagh, P. R.

    2008-01-01

    Musculoskeletal changes, particularly in the lower extremities, are an established consequence of long-duration space flight despite exercise countermeasures. It is widely believed that disuse and reduction in load bearing are key to these physiological changes, but no quantitative data characterizing the on-orbit movement environments currently exist. Here we present data from the Foot Experiment (E318) regarding astronaut activity on the ground and on-orbit during typical days from 4 International Space Station (ISS) crew members who flew during increments 6, 8, 11, and 12.

  17. Measurement of muscle actions and foot reaction forces from crew members during entire working days on the International Space Station (ISS)

    International Nuclear Information System (INIS)

    We present pilot work in preparation for ISS Experiment 318, which will investigate changes in lower limb daily mechanical loading and muscular activity profiles that have been implicated in bone mineral loss and muscle atrophy during spaceflight. Prototype equipment for the musculo-skeletal rack of the Human Research Facility (HRF) was used in conjunction with the Ambulatory Data Acquisition System to record and store data. Right foot ground reaction force profiles, right leg EMG activity profiles from the tibialis anterior and vastus medialis, and joint angular excursion profiles from the right knee and ankle were collected during five minutes each of forward and backward running in 1g as well as over a twelve hour period of activities during daily living. Ground reaction force profiles were analyzed to provide an estimate of 1g daily mechanical load stimulus, while EMG and joint angle profiles characterized the role of individual muscles in generating and absorbing energy

  18. Forcing factors of cloud-to-ground lightning over Iberia: regional-scale assessments

    Directory of Open Access Journals (Sweden)

    J. A. Santos

    2013-07-01

    Full Text Available Cloud-to-ground lightning in a sector covering the Iberian Peninsula, the Balearic Islands and nearby seas (36–44° N, 10° W–5° E is analysed in the period from 2003 to 2009 (7 yr. Two Iberian lightning detection networks, composed of 18 sensors over Portugal and Spain, are combined for the first time in the present study. The selected characteristics are cloud-to-ground flashes (CGFs, first stroke peak current, polarity and multiplicity (number of strokes in a given flash. This study examines the temporal (on hourly, monthly and seasonal timescales and spatial variability of CGFs. The influence of five forcing factors on lightning (elevation, lifted index, convective available potential energy and daily minimum and maximum near-surface air temperatures over the Iberian sector is also assessed. For regional-scale assessments, six subsectors with different climatic conditions were analysed separately. Despite important regional differences, the strongest lightning activity occurs from late spring to early autumn, and mostly in the afternoon. Furthermore, CGFs are mainly located over high-elevation areas in late spring to summer, while they tend to occur over the sea in autumn. The results suggest that (1 orographically forced thunderstorms over mountainous areas, mostly from May to September, (2 tropospheric buoyancy forcing over western-central and northern regions in summer and over the Mediterranean regions in autumn, and (3 near-surface thermal contrasts from October to February largely control the location of lightning in Iberia. There is no evidence of different forcings by polarity. A clear correspondence between summertime precipitation patterns and CGFs is also found.

  19. Population of ground-state rotational bands of superheavy nuclei produced in complete fusion reactions

    International Nuclear Information System (INIS)

    Using the statistical and quantum diffusion approaches, we study the population of ground-state rotational bands of superheavy nuclei produced in the fusion-evaporation reactions 208Pb(48Ca,2n)254No, 206Pb(48Ca,2n)252No, and 204Hg(48Ca,2n)250Fm. By describing the relative intensities of E2 transitions between the rotational states, the entry spin distributions of residual nuclei, and the excitation functions for these reactions, the dependence of fission barriers of shell-stabilized nuclei on angular momentum is investigated.

  20. Thinking anew causality problems for the radiation reaction force

    CERN Document Server

    Souza, Reinaldo de Melo e

    2015-01-01

    In this work, we analyze a Lagrangian formalism recently proposed to approach the issue of the Abraham-Lorentz force. Instead of involving only position and velocity, as usual in Classical Mechanics, this Lagrangian involves the acceleration of the charge. We find the conserved momentum of the charge in the absence of any field and show that it contains an acceleration term. This enables us to re-visit the well-known pre-acceleration problem and show that, contrary to what has been widely believed, it is not related to any violation of causality.

  1. BALANCE : a computer program for calculating mass transfer for geochemical reactions in ground water

    Science.gov (United States)

    Parkhurst, David L.; Plummer, L. Niel; Thorstenson, Donald C.

    1982-01-01

    BALANCE is a Fortran computer designed to define and quantify chemical reactions between ground water and minerals. Using (1) the chemical compositions of two waters along a flow path and (2) a set of mineral phases hypothesized to be the reactive constituents in the system, the program calculates the mass transfer (amounts of the phases entering or leaving the aqueous phase) necessary to account for the observed changes in composition between the two waters. Additional constraints can be included in the problem formulation to account for mixing of two end-member waters, redox reactions, and, in a simplified form, isotopic composition. The computer code and a description of the input necessary to run the program are presented. Three examples typical of ground-water systems are described. (USGS)

  2. (Environmental investigation of ground water contamination at Wright-Patterson Air Force Base, Ohio)

    Energy Technology Data Exchange (ETDEWEB)

    Thompson, Bill

    1991-10-01

    In April 1990, Wright-Patterson Air Force Base (WPAFB), initiated an investigation to evaluate a potential Comprehensive Environmental Response, Compensation, and Liability Act (CERCLA) removal action to prevent, to the extent practicable, the offsite migration of contaminated ground water from WPAFB. WPAFB retained the services of the Environmental Management Operations (EMO) and its principle subcontractor, International Technology Corporation (IT) to complete Phase 1 of the environmental investigation of ground-water contamination at WPAFB. Phase 1 of the investigation involves the short-term evaluation and potential design for a program to remove ground-water contamination that appears to be migrating across the western boundary of Area C, and across the northern boundary of Area B along Springfield Pike. Primarily, Task 4 of Phase 1 focuses on collection of information at the Area C and Springfield Pike boundaries of WPAFB. This Sampling and Analysis Plan (SAP) has been prepared to assist in completion of the Task 4 field investigation and is comprised of the Quality Assurance Project Plan (QAPP) and the Field Sampling Plan (FSP).

  3. Aerodynamic forces and flow structures of the leading edge vortex on a flapping wing considering ground effect

    International Nuclear Information System (INIS)

    The aim of this work is to provide an insight into the aerodynamic performance of the beetle during takeoff, which has been estimated in previous investigations. We employed a scaled-up electromechanical model flapping wing to measure the aerodynamic forces and the three-dimensional flow structures on the flapping wing. The ground effect on the unsteady forces and flow structures were also characterized. The dynamically scaled wing model could replicate the general stroke pattern of the beetle's hind wing kinematics during takeoff flight. Two wing kinematic models have been studied to examine the influences of wing kinematics on unsteady aerodynamic forces. In the first model, the angle of attack is asymmetric and varies during the translational motion, which is the flapping motion of the beetle's hind wing. In the second model, the angle of attack is constant during the translational motion. The instantaneous aerodynamic forces were measured for four strokes during the beetle's takeoff by the force sensor attached at the wing base. Flow visualization provided a general picture of the evolution of the three-dimensional leading edge vortex (LEV) on the beetle hind wing model. The LEV is stable during each stroke, and increases radically from the root to the tip, forming a leading-edge spiral vortex. The force measurement results show that the vertical force generated by the hind wing is large enough to lift the beetle. For the beetle hind wing kinematics, the total verbeetle hind wing kinematics, the total vertical force production increases 18.4% and 8.6% for the first and second strokes, respectively, due to the ground effect. However, for the model with a constant angle of attack during translation, the vertical force is reduced during the first stroke. During the third and fourth strokes, the ground effect is negligible for both wing kinematic patterns. This finding suggests that the beetle's flapping mechanism induces a ground effect that can efficiently lift its body from the ground during takeoff. (paper)

  4. Forced expiratory volume is associated with cardiovascular and cortisol reactions to acute psychological stress

    OpenAIRE

    Carroll, Douglas; Bibbey, Adam; Roseboom, Tessa J.; Phillips, Anna C.; Ginty, Annie T.; Rooij, Susanne R.

    2012-01-01

    It has been argued that blunted cardiovascular and cortisol reactions to acute psychological stress reflect a dysregulation of the neural system that supports motivation. We examined the association between forced expiratory volume in one second, an effort, hence motivation, dependent measure of lung function measured by spirometry, and cardiovascular and cortisol reactions to a battery of standard psychological stress tasks (Stroop, mirror-tracing, speech), assessed seven years later among ...

  5. A new electromagnetic NDI-technique based on the measurement of source-sample reaction forces

    Science.gov (United States)

    Fitzpatrick, G. L.; Skaugset, R. L.; Shih, W. C. L.

    2001-04-01

    Faraday's law of induction, Lenz's law, the Lorentz force law and Newton's third law, taken together, insure that sources (e.g., coil sources) of time-dependent electromagnetic fields, and nearby "nonmagnetic" electrical conductors (e.g., aluminum), always experience mutually repulsive (source-conductor) forces. This fact forms the basis for a new method for detecting cracks and corrosion in (aging) multi-layer airframes. The presence of cracks or corrosion (e.g., material thinning) in these structures is observed to reduce (second-harmonic) source-conductor reaction forces.

  6. Calculations of three-nucleon reactions with N3LO chiral forces: achievements and challenges

    International Nuclear Information System (INIS)

    We discuss the application of the chiral N3LO forces to three-nucleon reactions and point to the challenges which will have to be addressed. Present approaches to solve three-nucleon Faddeev equations are based on a partial-wave decomposition. A rapid increase of the number of terms contributing to the chiral three-nucleon force when increasing the order of the chiral expansion from N2LO to N3LO forced us to develop a fast and effective method of automatized partial-wave decomposition. At low energies of the incoming nucleon below ?20 MeV, where only a limited number of partial waves is required, this method allowed us to perform calculations of reactions in the three-nucleon continuum using N3LO two- and three-nucleon forces. It turns out that inclusion of consistent chiral interactions, with relativistic 1/m corrections and short-range 2?-contact term omitted in the N3LO three-nucleon force, does not explain the long standing low energy Ay-puzzle. We discuss problems arising when chiral forces are applied at higher energies, where large three-nucleon force effects are expected. It seems plausible that at higher energies, due to a rapid increase of a number of partial waves required to reach convergent results, a three-dimensional formulation of the Faddeev equations which avoids partial-wave decomposition is desirable. (paper)

  7. ND elastic scattering, breakup reactions and the search for three-nucleon forces

    International Nuclear Information System (INIS)

    The present experimental situation in the nd scattering system is reviewed for the elastic scattering and for the breakup reaction channel. Faddeev calculations show the need of precise two-nucleon input in higher partial waves, especially p-waves for the description of spin-dependent observables. The experimental effort in the nd breakup reaction studies is to be guided by reliable Faddeev predictions. The sensitivity of specific kinematical situations has to be studied carefully. The inclusion of three-body forces in these calculations should be combined with a careful check of Coulomb correction methods. The pd breakup reaction could yield more information than the experimentally more difficult nd studies. (orig.)

  8. Stress-modulated driving force for lithiation reaction in hollow nano-anodes

    Science.gov (United States)

    Jia, Zheng; Li, Teng

    2015-02-01

    Lithiation of a crystalline silicon anode proceeds by the movement of an atomically sharp reaction front that separates a pristine crystalline phase and a fully-lithiated amorphous phase. The velocity of the reaction front is limited rather by the reaction rate at the lithiation front than by the diffusivity of lithium ions in the amorphous lithiated phase. Experiments on solid nanoparticle/nanowire silicon anodes show an initial rapid advancing of reaction front at the initial stage of lithiation, followed by an apparent slowing or even halting of the reaction front propagation. Lithiation-induced stresses during lithiation are attributed to alter the driving force of lithiation and thus result in the observed slowing of reaction front. Recent experiments on lithiation of hollow silicon nanowires reveals similar slowing of reaction front, however, quantitative study of the effect of lithiation-associated stress on the driving force of lithiation still lacks so far. Here, through chemo-mechanical modeling and theoretical formulation, we present a comprehensive study on lithiation-induced stress field and its contribution to the driving force of lithiation reaction in hollow silicon nanowire anodes. We show that hollow silicon nano-anodes could be fully lithiated with lower stress-induced energy barrier than solid silicon nano-anodes. As a result, it is expected that the hollow nanowires and nanoparticles may serve as an optimal structural design for high-performance anodes of lithium-ion batteries. Results from the present study shed light on a number of open questions of lithiation kinetics of silicon-based anodes in recent literature and offer insight on developing silicon-based anodes with high charging capacity and high charging rate.

  9. The study of vertical ground reaction during walk of Czech women

    OpenAIRE

    Pavel Korvas; Radek Musil; Jan Došla; Kate?ina Kolá?ová; Jind?ich Pavlík; Jan Šenký?

    2013-01-01

    The aim of this study was to find whether it is possible to explain different plantar loading during absorption and propulsive stages of stance in the observed persons by means of basic body indicators or time characteristics of gait. Fifty-one healthy women participated in the study; their age range was between 30 and 60 years of age. The women were divided into two groups according to whether they reached higher values of vertical ground reaction during absorption (group A, 8 women, 16 %) o...

  10. Dynamics of proton transfer reactions of model base pairs in the ground and excited states: Revisited

    Science.gov (United States)

    Fuke, Kiyokazu; Ishikawa, Haruki

    2015-03-01

    A review of the proton transfer reactions (PTR) of model base pairs such as the 7-azaindole and 1-azacarbazole dimers is presented, including some of the recent progress in the laser spectroscopy of these dimers. Advances in computational chemistry now allow to calculate reliable potential energy surfaces of the excited-state PTR, which is indispensable to understand the experimental results. The comprehensive results on the spectroscopy and reactivity of these dimers are outlined for fully explaining the excited state PTR of model base pairs on the basis of the current theoretical studies. Moreover, the recent studies on the PTR in the ground state relating to a back proton translocation of tautomeric dimer of 7-azaindole are presented. Finally, the outlook on the study of the PTR of model base pairs is addressed to further explore the reaction dynamics of these benchmark systems.

  11. Variational Scheme to Compute Protein Reaction Pathways Using Atomistic Force Fields with Explicit Solvent

    Science.gov (United States)

    a Beccara, S.; Fant, L.; Faccioli, P.

    2015-03-01

    We introduce a variational approximation to the microscopic dynamics of rare conformational transitions of macromolecules. Within this framework it is possible to simulate on a small computer cluster reactions as complex as protein folding, using state of the art all-atom force fields in explicit solvent. We test this method against MD simulations of the folding of an ? and a ? protein performed with the same all-atom force field on the Anton supercomputer. We find that our approach yields results consistent with those of MD simulations, at a computational cost orders of magnitude smaller.

  12. Impact of walking speed and slope of the ground on axial force of poles in Nordic walking

    Directory of Open Access Journals (Sweden)

    Martin Pšurný

    2013-09-01

    Full Text Available BACKGROUND: Nordic walking (NW, due to its attractiveness and convenience of equipment, is becoming more popular and utilised in the areas of sports, recreation and physiotherapy. Some of its impacts on load to the body have not yet been sufficiently explored. OBJECTIVE: The objective of the study was to determine the impact of walking speed and slope of the ground on the magnitude of axial forces, transferred to the poles by upper extremities during NW. METHODS: The study was participated in by 17 healthy subjects, aged 25.9?±?3.6 years, who went through 12 independent measurements on a treadmill in various speeds (6.0; 6.6; 7.2 and 7.8?km?•?h–1 and slopes (0; 5 and 7.5%. These measurements provided us with values of basic spatiotemporal variables, characterizing NW performance and force variables, acting on the poles. RESULTS: Increased walking speed led to increase in cycle frequency (p?force and average poling force (p?ground had no significant impact on the magnitude of time and dynamic variables. CONCLUSIONS: Increased walking speed during NW increases the force, generated by the upper extremities on the poles. During NW it is possible to prefer walking speed rather than to change the slope of the ground for those patients, who are indicated to strengthen upper extremities.

  13. A theoretical investigation of ground effects on USB configurations

    Science.gov (United States)

    Lan, C. E.

    1979-01-01

    A formulation predicts the variation of circulation forces and jet reaction forces in ground proximity as a function of ground height. The predicted results agree well with available experimental data. It is shown that the wing-alone theory is not capable of predicting the ground effect for USB configurations.

  14. Effects of brain polarization on reaction times and pinch force in chronic stroke

    Directory of Open Access Journals (Sweden)

    Giraux Pascal

    2006-11-01

    Full Text Available Abstract Background Previous studies showed that anodal transcranial DC stimulation (tDCS applied to the primary motor cortex of the affected hemisphere (M1affected hemisphere after subcortical stroke transiently improves performance of complex tasks that mimic activities of daily living (ADL. It is not known if relatively simpler motor tasks are similarly affected. Here we tested the effects of tDCS on pinch force (PF and simple reaction time (RT tasks in patients with chronic stroke in a double-blind cross-over Sham-controlled experimental design. Results Anodal tDCS shortened reaction times and improved pinch force in the paretic hand relative to Sham stimulation, an effect present in patients with higher impairment. Conclusion tDCS of M1affected hemisphere can modulate performance of motor tasks simpler than those previously studied, a finding that could potentially benefit patients with relatively higher impairment levels.

  15. A method of hydraulic reaction force computation due to fluid jet at a steamline break

    International Nuclear Information System (INIS)

    A method of hydraulic jet reaction force computation is presented at a 100% steamline break. The steamline break analysis is performed by the use of NOTRUMP code. Formation of supersonic flow at the converging-diverging flow restrictor is computed with a homogeneous equilibrium model. However, consideration is given on the slip ratio of the liquid and steam phases, thermal non-equilibrium effects, and normal and oblique shocks

  16. High force-to-volume Terfenol-D reaction mass actuator: modeling and design

    Science.gov (United States)

    Dozor, David M.; Jagannathan, Shankar; Gerver, Michael J.; Fenn, Ralph C.; Logan, D. M.; Berry, John R.

    1996-05-01

    A high force to volume ratio magnetostrictive reaction mass actuator has been designed and developed. The actuator operates as a resonant device allowing the stored strain energy to be utilized. A discussion of the design issues associated with this actuator are presented. In addition, preliminary data is presented for this actuator. This data includes a linear analysis, evidence of parameter variation, and preliminary small signal tests intended to explore this behavior.

  17. Reaction force of percussive corer, rotary-friction corer, and rotary-percussive corer

    Science.gov (United States)

    Chang, Zensheu; Sherrit, Stewart; Badescu, Mircea; Bao, Xiaoqi; Bar-Cohen, Yoseph; Backes, Paul

    2006-01-01

    Future NASA exploration missions will increasingly require sampling, in-situ analysis and possibly the return of material to Earth for laboratory analysis. To address these objective, effective and optimized drilling techniques are needed. This requires developing comprehensive tools to be able to determine analytically what takes place during the operation and what are the control parameters that can be enhanced. In this study, three types of coring techniques were studied and were identified as potential candidates for operation from a possible future Mars Sample Return (MSR) mission rover. These techniques include percussive, rotary-friction, and rotary-percussive coring. Theoretical models were developed to predict the dynamic reaction forces transmitted from these three types of corers to the robotic arms that hold them. The predicted reaction forces will then be used in a dynamic simulation environment to simulate a representative corer tool to obtain a best estimate of a tool that can be operated from a small rover. The predicted dynamic reaction forces will be presented in this paper.

  18. The gravitational radiation reaction force of a continuous medium. I. Perturbation of a quasi-newtonian motion

    International Nuclear Information System (INIS)

    We determine, within the general theory of relativity, the equations of motion in the slow approximation of a continuous medium in which the forces from material stresses do not play a leading part with respect to the gravitational forces. The gravitational radiation reaction force appears as a disturbing force in the post-post-newtonian equations of motion. Then, we deduce the formula for the variation of the energy of the system due to the gravitational radiation

  19. Low-energy neutron-deuteron reactions with N3LO chiral forces

    International Nuclear Information System (INIS)

    We solve three-nucleon Faddeev equations with nucleon-nucleon and three-nucleon forces derived consistently in the framework of chiral perturbation theory at next-to-next-to-next-to-leading order in the chiral expansion. In this first investigation we include only matrix elements of the three-nucleon force for partial waves with the total two-nucleon (three-nucleon) angular momenta up to 3 (5/2). Low-energy neutron-deuteron elastic scattering and deuteron breakup reaction are studied. Emphasis is put on Ay puzzle in elastic scattering and cross sections in symmetric-space-star and neutron-neutron quasi-free-scattering breakup configurations, for which large discrepancies between data and theory have been reported. (orig.)

  20. Low-energy neutron-deuteron reactions with N3LO chiral forces

    CERN Document Server

    Golak, J; Topolnicki, K; Witala, H; Epelbaum, E; Krebs, H; Kamada, H; Meissner, Ulf-G; Bernard, V; Maris, P; Vary, J; Binder, S; Calci, A; Hebeler, K; Langhammer, J; Roth, R; Nogga, A; Liebig, S; Minossi, D

    2014-01-01

    We solve three-nucleon Faddeev equations with nucleon-nucleon and three-nucleon forces derived consistently in the framework of chiral perturbation theory at next-to-next-to-next-to-leading order in the chiral expansion. In this first investigation we include only matrix elements of the three-nucleon force for partial waves with the total two-nucleon (three-nucleon) angular momenta up to 3 (5/2). Low-energy neutron-deuteron elastic scattering and deuteron breakup reaction are studied. Emphasis is put on Ay puzzle in elastic scattering and cross sections in symmetric-space-star and neutron-neutron quasi-free-scattering breakup configurations, for which large discrepancies between data and theory have been reported.

  1. Low-energy neutron-deuteron reactions with N{sup 3}LO chiral forces

    Energy Technology Data Exchange (ETDEWEB)

    Golak, J.; Skibinski, R.; Topolnicki, K.; Witala, H. [Jagiellonian University, M. Smoluchowski Institute of Physics, Krakow (Poland); Epelbaum, E.; Krebs, H. [Ruhr-Universitaet Bochum, Institut fuer Theoretische Physik II, Bochum (Germany); Kamada, H. [Kyushu Institute of Technology, Department of Physics, Faculty of Engineering, Kitakyushu (Japan); Meissner, Ulf G. [Universitaet Bonn, Helmholtz-Institut fuer Strahlen- und Kernphysik and Bethe Center for Theoretical Physics, Bonn (Germany); JARA - High Performance Computing Forschungszentrum Juelich, Institute for Advanced Simulation, Institut fuer Kernphysik, Juelich Center for Hadron Physics, Juelich (Germany); Bernard, V. [CNRS/Univ. Paris-Sud, Institut de Physique Nucleaire, Orsay (France); Maris, P.; Vary, J. [Iowa State University, Department of Physics and Astronomy, Ames, Iowa (United States); Binder, S.; Calci, A.; Langhammer, J.; Roth, R. [Technische Universitaet Darmstadt, Institut fuer Kernphysik, Darmstadt (Germany); Hebeler, K. [Technische Universitaet Darmstadt, Institut fuer Kernphysik, Darmstadt (Germany); GSI Helmholtzzentrum fuer Schwerionenforschung GmbH, Extreme Matter Institute EMMI, Darmstadt (Germany); Nogga, A. [Juelich Center for Hadron Physics, Forschungszentrum Juelich, Institut fuer Kernphysik, Institute for Advanced Simulation, Juelich (Germany); Liebig, S.; Minossi, D. [Juelich Center for Hadron Physics, Forschungszentrum Juelich, Institut fuer Kernphysik, Juelich (Germany)

    2014-11-15

    We solve three-nucleon Faddeev equations with nucleon-nucleon and three-nucleon forces derived consistently in the framework of chiral perturbation theory at next-to-next-to-next-to-leading order in the chiral expansion. In this first investigation we include only matrix elements of the three-nucleon force for partial waves with the total two-nucleon (three-nucleon) angular momenta up to 3 (5/2). Low-energy neutron-deuteron elastic scattering and deuteron breakup reaction are studied. Emphasis is put on A{sub y} puzzle in elastic scattering and cross sections in symmetric-space-star and neutron-neutron quasi-free-scattering breakup configurations, for which large discrepancies between data and theory have been reported. (orig.)

  2. Infrared radiative forcing of CFC substitutes and their atmospheric reaction products

    Science.gov (United States)

    Papasavva, Stella; Tai, Stephanie; Illinger, Karl H.; Kenny, Jonathan E.

    1997-06-01

    We have employed the radiative forcing function recently computed by Pinnock et al. [1995], in conjunction with infrared cross sections and vibrational frequencies calculated with ab initio quantum-mechanical methods, to estimate the instantaneous infrared radiative forcing terms ?tot of a number of CFC substitutes and their atmospheric reaction products. The computed quantities ?tot are compared with those obtained by Pinnock et al. [1995] employing experimental infrared spectra. In particular, Gaussian-92TM software has been utilized, at the MP2/6-31G** level of theory, to provide computational estimates of these quantities. Our results agree with the former, with a mean and a standard deviation of the difference of +3% and 15%, respectively. An error analysis is provided to assess the utility of the method. The capability of quantum-mechanical computational methods to explore structural trends in radiative and physicochemical properties is exploited for the molecular systems examined here.

  3. Radiation-Reaction Force on a Small Charged Body to Second Order

    Science.gov (United States)

    Moxon, Jordan; Flanagan, Eanna

    2015-04-01

    In classical electrodynamics, an accelerating charge emits radiation and experiences a corresponding radiation reaction force, or self force. We extend to greater precision (higher order in perturbation theory) a previous rigorous derivation of the electromagnetic self force in flat spacetime by Gralla, Harte, and Wald. The method introduced by Gralla, Harte, and Wald computes the self-force from the Maxwell field equations and conservation of stress-energy, and does not require regularization of a singular point charge, as has been necessary in prior computations. For our higher order compuation, it becomes necessary to adopt an adjusted definition of the mass of the body to avoid including self-energy from the electromagnetic field sourced during the history of the body. We derive the evolution equations for the mass, spin, and center of mass position of an extended body through second order using our adjusted formalism. The final equations give an acceleration dependent evolution of the spin (self-torque), as well as a mixing between the extended body effects and the acceleration dependent effects on the overall body motion.

  4. Biomechanical factors affecting the peak hand reaction force during the bimanual arrest of a moving mass.

    Science.gov (United States)

    DeGoede, Kurt M; Ashton-Miller, James A; Schultz, Albert B; Alexander, Neil B

    2002-02-01

    Fall-related wrist fractures are among the most common fractures at any age. In order to learn more about the biomechanical factors influencing the impact response of the upper extremities, we studied peak hand reaction force during the bimanual arrest of a 3.4 kg ballistic pendulum moving toward the subject in the sagittal plane at shoulder height. Twenty healthy young and 20 older adults, with equal gender representation, arrested the pendulum after impact at one of three initial speeds: 1.8, 2.3, or 3.0 m/sec. Subjects were asked to employ one of three initial elbow angles: 130, 150, or 170 deg. An analysis of variance showed that hand impact force decreased significantly as impact velocity decreased (50 percent/m/s) and as elbow angle decreased (0.9 percent/degree). A two segment sagittally-symmetric biomechanical model demonstrated that two additional factors affected impact forces: hand-impactor surface stiffness and damping properties, and arm segment mass. We conclude that hand impact force can be reduced by more than 40 percent by decreasing the amount of initial elbow extension and by decreasing the velocity of the hands and arms relative to the impacting surface. PMID:11871596

  5. Constructing a Mass-Current Radiation-Reaction Force for Numerical Simulations

    Science.gov (United States)

    Rezzolla, Luciano; Shibata, Masaru; Asada, Hideki; Baumgarte, Thomas W.; Shapiro, Stuart L.

    1999-11-01

    We present a new set of 3.5 post-Newtonian equations in which Newtonian hydrodynamics is coupled to the nonconservative effects of gravitational radiation emission. Our formalism differs in two significant ways from a similar 3.5 post-Newtonian approach proposed by Blanchet. First, we concentrate only on the radiation-reaction effects produced by a time-varying mass-current quadrupole Sij. Second, we adopt a gauge in which the radiation-reaction force densities depend on the fourth time derivative of Sij, rather than on the fifth, as in Blanchet's approach. This difference makes our formalism particularly well-suited to numerical implementation and could prove useful in performing fully numerical simulations of the recently discovered r-mode instability for rotating neutron stars subject to axial perturbations.

  6. Constructing a Mass-Current Radiation-Reaction Force For Numerical Simulations

    CERN Document Server

    Rezzolla, L; Asada, H; Baumgarte, T W; Shapiro, S L

    1999-01-01

    We present a new set of 3.5 Post-Newtonian equations in which Newtonian hydrodynamics is coupled to the nonconservative effects of gravitational radiation emission. Our formalism differs in two significant ways from a similar 3.5 Post-Newtonian approach proposed by Blanchet (1993, 1997). Firstly we concentrate only on the radiation-reaction effects produced by a time-varying mass-current quadrupole $S_{ij}$. Secondly, we adopt a gauge in which the radiation-reaction force densities depend on the fourth time derivative of $S_{ij}$, rather than on the fifth, as in Blanchet's approach. This difference makes our formalism particularly well-suited to numerical implementation and could prove useful in performing fully numerical simulations of the recently discovered $r$-mode instability for rotating neutron stars subject to axial perturbations.

  7. Atomistic insights into the conversion reaction in iron fluoride: a dynamically adaptive force field approach.

    Science.gov (United States)

    Ma, Ying; Garofalini, Stephen H

    2012-05-16

    Nanoscale metal fluorides are promising candidates for high capacity lithium ion batteries, in which a conversion reaction upon exposure to Li ions enables access to the multiple valence states of the metal cation. However, little is known about the molecular mechanisms and the reaction pathways in conversion that relate to the need for nanoscale starting materials. To address this reaction and the controversial role of intercalation in a promising conversion material, FeF(2), a dynamically adaptive force field that allows for a change in ion charge during reactions is applied in molecular dynamics simulations. Results provide the atomistic view of this conversion reaction that forms nanocrystals of LiF and Fe(0) and addresses the important controversy regarding intercalation. Simulations of Li(+) exposure on the low energy FeF(2) (001) and (110) surfaces show that the reaction initiates at the surface and iron clusters as well as crystalline LiF are formed, sometimes via an amorphous Li-F. Li intercalation is also observed as a function of surface orientation and rate of exposure to the Li, with different behavior on (001) and (110) surfaces. Intercalation along [001] rapid transport channels is accompanied by a slight reduction of charge density on multiple nearby Fe ions per Li ion until enough Li saturates a region and causes the nearby Fe to lose sufficient charge to become destabilized and form the nanocluster Fe(0). The resultant nanostructures are fully consistent with postconversion TEM observations, and the simulations provide the solution to the controversy regarding intercalation versus conversion and the atomistic rationale for the need for nanoscale metal fluoride starting particles in conversion cathodes. PMID:22545624

  8. Theoretical study on the reaction of the 2? ground state of TiS+ with COS in the gas phase

    International Nuclear Information System (INIS)

    Two major reactions of the 2? ground state of TiS+ with COS in the gas phase have been studied by using density functional theory at B3LYP/DZVP level: the O/S exchange reaction (TiS++COS->TiO++CS2) and the S-transfer reaction (TiS++COS->TiS2++CO). It is found that the O/S exchange reaction is one-step reaction with an activation barrier of 15.1 kJ/mol relative to the reactants, whereas for the S-transfer reaction, two parallel reaction channels have been identified. From the two cis-trans isomer intermediates (IM3 and IM5) formed Initially from the S atom of COS attacking TiS+, the two reaction channels proceed via a four-center and a three-member transition states with activation barriers of 51.3 and 40.7 kJ/mol, respectively, and yield their corresponding products TiS2+-1(2B2)andTiS2+-2(2A1). Besides, one two-step mechanism of the third major reaction of TiS+ with COS (TiS++COS->Ti++S2+CO) has been also identified

  9. Self-consistent HF-RPA description of electron and photon nuclear reactions with Skyrme forces

    International Nuclear Information System (INIS)

    A mean-field nuclear dynamics is investigated in the analysis of nuclear electromagnetic processes at low and intermediate (q, ?) transfers. The theoretical framework is a self-consistent HF-RPA theory with Skyrme forces formulated in the one-nucleon energy continuum. We review the results obtained in the Skyrme HF-RPA model by focusing on some specific aspects of the theoretical frame and discussing their incidence in the prediction of data. Main points of interest are: (i) the quasiparticle formulation of the Skyrme HF-RPA nuclear dynamics with the identification of a quasi-particle effective mass, (ii) the gauge-invariance of the Skyrme Hamiltonian which produces nuclear electromagnetic currents satisfying the continuity equation, (iii) the excitation and decay properties of the one-nucleon energy continuum. The problems dealt with in the discussion of experimental data are the following: the quasi-deuteron effect in (?, p) and (?, n) reactions of closed shell nuclei at energies E??300 MeV, Giant Multipole Resonances versus momentum transfer in inclusive (e, e' x) responses, the reaction mechanism in polarized ( vector e, e' x) angular distributions at q?200 MeV/c, the evaluation of the missing strength in inclusive (e, e') longitudinal responses at high momentum transfer, final state interactions and missing momentum distributions in coincidence (e, e' p) reactions in the quasi-elastic region. (orig.)

  10. Self-consistent HF-RPA description of electron and photon nuclear reactions with Skyrme forces

    Science.gov (United States)

    Maria Saruis, Anna

    1993-12-01

    A mean-field nuclear dynamics is investigated in the analysis of nuclear electromagnetic processes at low and intermediate ( q, w) transfers. The theoretical framework is a self-consistent HF-RPA theory with Skyrme forces formulated in the one-nucleon energy continuum. We review the results obtained in the Skyrme HF-RPA model by focusing on some specific aspects of the theoretical frame and discussing their incidence in the prediction of data. Main points of interest are: (i) the quasiparticle formulation of the Skyrme HF-RPA nuclear dynamics with the identification of a quasi-particle effective mass, (ii) the gauge-invariance of the Skyrme Hamiltonian which produces nuclear electromagnetic currents satisfying the continuity equation, (iii) the excitation and decay properties of the one-nucleon energy continuum. The problems dealt with in the discussion of experimental data are the following: the quasi-deuteron effect in (?, p) and (?, n) reactions of closed shell nuclei at energies E? ? 300 MeV, Giant Multipole Resonances versus momentum transfer in inclusive ( e, e?x) responses, the reaction mechanism in polarized ( overlinee, e?x) angular distributions at q ? 200 {MeV}/{c}, the evaluation of the missing strength in inclusive ( e, e?) longitudinal responses at high momentum transfer, final state interactions and missing momentum distributions in coincidence ( e, e?p) reactions in the quasi-elastic region.

  11. Influence of walking speed in backpacker's gait : ground reaction forces and plantar pressure analysis

    OpenAIRE

    Figueiredo, Maria Cristina Pinto Leite Braamcamp

    2011-01-01

    O modo como nos deslocamos influencia os parâmetros biomecânicos da marcha, alterando-os, podendo vir a originar lesões a curto ou longo prazo. Com este trabalho pretendeu-se fazer, em primeiro lugar, uma revisão sistemática da literatura acerca do que consiste a influência da velocidade nos parâmetros biomecânicos da marcha e, depois, estudar o efeito que a velocidade tem nas forças de reacção ao solo e na pressão plantar durante a marcha quando se transporta, ou não, uma carga. Assim, um do...

  12. Extraction of ground reaction forces for real-time synthesis of walking sounds

    DEFF Research Database (Denmark)

    Serafin, Stefania; Turchet, Luca

    2009-01-01

    A shoe-independent system to synthesize real-time footstep sounds on different materials has been developed. A footstep sound is considered as the result of an interaction between an exciter (the shoe) and a resonator (the floor). To achieve our goal, we propose two different solutions. The first solution is based on contact microphones attached on the exterior part of each shoe, which capture the sound of a footstep. The second approach consists on using microphones placed on the floor. In both situations, the captured sound is analysed and used to control a sound synthesis engine. We discuss advantages and disadvantages of the two approaches.

  13. Force

    CERN Document Server

    Graybill, George

    2007-01-01

    Forces are at work all around us. Discover what a force is, and different kinds of forces that work on contact and at a distance. We use simple language and vocabulary to make this invisible world easy for students to ""see"" and understand. Examine how forces ""add up"" to create the total force on an object, and reinforce concepts and extend learning with sample problems.

  14. Electromagnetic-energy-density distribution around a ground-state hydrogen atom and connection with van der Waals forces

    International Nuclear Information System (INIS)

    A spinless hydrogen atom coupled to the electromagnetic field is considered within the context of nonrelativistic quantum electrodynamics. The atom-field interaction is taken in the minimal-coupling form and the Coulomb gauge is used. When the coupled system is in its ground state the electromagnetic field fluctuates away from the vacuum state and the atom has virtual admixtures from its uncoupled lowest eigenstate. The electric- and magnetic-field-energy densities that arise from the fluctuations are determined as functions of the distance from the atom. The relationship between these field-energy densities and the retarded long-range van der Waals forces is also discussed

  15. Novel and Unique Expression for the Radiation Reaction Force, Relevance of Newton's Third Law and Tunneling

    CERN Document Server

    Gromes, Dieter

    2014-01-01

    We derive the radiation reaction by taking into account that the acceleration of the charge is caused by the interaction with some heavy source particle. In the non relativistic case this leads, in contrast to the usual approach, immediately to a result which is Galilei invariant. Simple examples show that there can be small regions of extremely low velocity where the energy requirements cannot be fulfilled, and which the charged particle can only cross by quantum mechanical tunneling. The relativistic generalization is rather straight forward and leads to a unique result. The force is a four-vector, but only if the presence of the source is taken into account as well. It contains no third derivatives of the position as the Lorentz-Abraham-Dirac equation, and consequently no run away solutions. All examples considered so far give reasonable results.

  16. Reaction forces due to the decompression of pressurized vessels filled with two-phase fluids

    International Nuclear Information System (INIS)

    A unique fluid behavioral model which is applicable to many homogeneous multiphase fluids is used as a generic model to examine the reaction forces developed by the decompression of pressurized vessels filled with single component two-phase fluids. The decompression is the result of the sudden creation of an outflow area such as by the accidental puncture of the vessel shell or the rupture of a pipe connection at the vessel. The study includes the treatment of two basic initial conditions: the case of a vessel completely filled with a saturated liquid, and the case of a vessel partially filled with a saturated liquid and covered with its saturated vapor, that is, the two region stratified condition. The principal variables include an expansion parameter which characterizes the fluid behavior in the two-phase domain, the vapor volume fraction, and the location of the outflow area for the stratified case

  17. Force and pressure analysis during occasional loaded gait

    OpenAIRE

    Castro, Marcelo Peduzzi; Santos, Rubim; Abreu, Sofia; Sousa, Helena; Machado, Leandro; Vilas Boas, João

    2012-01-01

    The aim of this study was to compare the ground reaction forces and plantar pressure parameters between unloaded and occasional loaded gait. The ground reaction forces and plantar pressure of 60 participants were recorded during unloaded and occasional loaded gait (wearing a backpack which raises the participant´s body mass index to 30). The results indicate an overall increase of forces and plantar pressure during occasional loaded gait where the absolute values were analyzed (p

  18. Describing electron motion in ultra-high intensity laser plasma interactions: the inclusion of a stochastic radiation reaction force

    Science.gov (United States)

    Ridgers, Christopher

    2014-10-01

    At intensities soon to be reached by next-generation laser facilities (exceeding 5 × 1022W/cm-2) electrons are accelerated so violently in the laser fields that they radiate energy (as gamma-ray photons) comparable to that they gain from the laser pulse. In this case the radiation reaction force becomes important in determining their motion. However, at these intensities the electric field in the electron's rest frame approaches the Schwinger field; the critical field of quantum electrodynamics where quantum effects on the radiation reaction force become crucial. In particular, the force transitions from a deterministic classical force to a stochastic force. I will compare electron motion when the radiation reaction is treated classically and stochastically, showing that the two treatments give the same result in the classical limit (correspondence) and that, surprisingly, a modified deterministic force (called the ``semi-classical'' model) can also be used when quantum effects are strong. I will also demonstrate that the semi-classical treatment fails to predict the rate of pair production by the emitted gamma-ray photons. To describe pair production one needs to adopt a new model for electron motion where the motion is described in terms of the evolution of a probability function in phase space as opposed to motion along a classical (deterministic) worldline.

  19. Grounding the Lexical Semantics of Verbs in Visual Perception using Force Dynamics and Event Logic

    CERN Document Server

    Siskind, J M

    2011-01-01

    This paper presents an implemented system for recognizing the occurrence of events described by simple spatial-motion verbs in short image sequences. The semantics of these verbs is specified with event-logic expressions that describe changes in the state of force-dynamic relations between the participants of the event. An efficient finite representation is introduced for the infinite sets of intervals that occur when describing liquid and semi-liquid events. Additionally, an efficient procedure using this representation is presented for inferring occurrences of compound events, described with event-logic expressions, from occurrences of primitive events. Using force dynamics and event logic to specify the lexical semantics of events allows the system to be more robust than prior systems based on motion profile.

  20. Formulation of Aerodynamic Forces on Helicopters in Non Uniform Flow with Scale Model Tests : Ground Effects.

    OpenAIRE

    Paquet, J. B.; Bourez, J. P.; Morgand, S.

    2014-01-01

    The simulation of helicopter recovery on a frigate is a very complex problem due to the non uniform flow around the frigate deck and the aeroelastic characteristics of the rotor. Small scale tests with helicopters are generally not in complete similarity and might be expensive. The number of state variables influencing the aerodynamic forces are too numerous so it is not possible to characterize all the configurations. So these tests with a small scale radio controlled helicopter attached to ...

  1. Precision study of ground state capture in the 14N(p,?)15O reaction

    International Nuclear Information System (INIS)

    The rate of the hydrogen-burning carbon-nitrogen-oxygen (CNO) cycle is controlled by the slowest process, 14N(p,?)15O, which proceeds by capture to the ground and several excited states in 15O. Previous extrapolations for the ground state contribution disagreed by a factor 2, corresponding to 15% uncertainty in the total astrophysical S factor. At the Laboratory for Underground Nuclear Astrophysics (LUNA) 400 kV accelerator placed deep underground in the Gran Sasso facility in Italy, a new experiment on ground state capture has been carried out at 317.8, 334.4, and 353.3 keV center-of-mass energy. Systematic corrections have been reduced considerably with respect to previous studies by using a Clover detector and by adopting a relative analysis. The previous discrepancy has been resolved, and ground state capture no longer dominates the uncertainty of the total S factor

  2. 3D FEM Numerical Simulation of Seismic Pile-supported Bridge Structure Reaction in Liquefying Ground

    OpenAIRE

    Ling Xianzhang, Tang Liang And Xu Pengju; Baydaa Hussain Maula

    2011-01-01

    This study examines the establishment of liquefied ground pile-soil-bridge seismic interaction analysis of three-dimensional finite element analysis method for the simulation of liquefied ground shaking table test of pile-soil seismic interaction analysis, undertake OpenSees finite element based numerical simulation platform, for the shaking table test based on two-phase saturated porous media, Comparative numerical and experimental results, detailed test pile dynamic response of bridge struc...

  3. Use of aquifer testing to complete ground water remedial design, shallow aquifer Nellis Air Force Base, Las Vegas, Nevada

    International Nuclear Information System (INIS)

    As part of a US Army Corps of Engineers-directed remedial action, a ground water treatment system is being installed at Site 27, Nellis Air Force Base, Las Vegas, Nevada. Twenty-three extraction wells were installed in the center and on the leading edge of a jet fuel plume of free and dissolved product in the uppermost (nonpotable) aquifer. The purpose of the extraction well system is to contain and remediate the plume, and to recover free product, which is over 10 feet thick in one well. Aquifer testing, including step and constant discharge tests, was conducted during well installation in order to (1) assist in location of subsequent wells, (2) obtain dynamic product thickness data for selection of wells in which skimmer pumps will be installed, (3) determine initial pumping rates, (4) determine aquifer parameters for modeling and optimization, and (5) provide baseline data on well performance to evaluate possible future biofouling

  4. Ground-water hydrology and water quality of the southern high plains aquifer, Melrose Air Force Range, Cannon Air Force Base, Curry and Roosevelt Counties, New Mexico, 2002-03

    Science.gov (United States)

    Langman, Jeff B.; Gebhardt, Fredrick E.; Falk, Sarah E.

    2004-01-01

    In cooperation with the U.S. Air Force, the U.S. Geological Survey characterized the ground-water hydrology and water quality at Melrose Air Force Range in east-central New Mexico. The purpose of the study was to provide baseline data to Cannon Air Force Base resource managers to make informed decisions concerning actions that may affect the ground-water system. Five periods of water-level measurements and four periods of water-quality sample collection were completed at Melrose Air Force Range during 2002 and 2003. The water-level measurements and water-quality samples were collected from a 29-well monitoring network that included wells in the Impact Area and leased lands of Melrose Air Force Range managed by Cannon Air Force Base personnel. The purpose of this report is to provide a broad overview of ground-water flow and ground-water quality in the Southern High Plains aquifer in the Ogallala Formation at Melrose Air Force Range. Results of the ground-water characterization of the Southern High Plains aquifer indicated a local flow system in the unconfined aquifer flowing northeastward from a topographic high, the Mesa (located in the southwestern part of the Range), toward a regional flow system in the unconfined aquifer that flows southeastward through the Portales Valley. Ground water was less than 55 years old across the Range; ground water was younger (less than 25 years) near the Mesa and ephemeral channels and older (25 years to 55 years) in the Portales Valley. Results of water-quality analysis indicated three areas of different water types: near the Mesa and ephemeral channels, in the Impact Area of the Range, and in the Portales Valley. Within the Southern High Plains aquifer, a sodium/chloride-dominated ground water was found in the center of the Impact Area of the Range with water-quality characteristics similar to ground water from the underlying Chinle Formation. This sodium/chloride-dominated ground water of the unconfined aquifer in the Impact Area indicates a likely connection with the deeper water-producing zone. No pesticides, explosives, volatile organic compounds, semivolatile organic compounds, organic halogens, or perchlorate were found in water samples from the Southern High Plains aquifer at the Range.

  5. Sudden drop in ground support produces force-related unload response in human overground walking

    DEFF Research Database (Denmark)

    Af Klint, Richard; Nielsen, Jens Bo

    2009-01-01

    Humans maneuver easily over uneven terrain. To maintain smooth and efficient gait the motor system needs to adapt the locomotor output to the walking environment. In the present study we investigate the role of sensory feedback in adjusting the soleus muscle activity during overground walking in 19 healthy volunteers. Subjects walked unrestrained over a hydraulically actuated platform. On random trials the platform was accelerated downward at 0.8 g, unloading the plantar flexor muscles in midstance or late stance. The drop of the platform resulted in a significant depression of the soleus muscle activity of -17.9% (SD 2) and -21.4% (SD 2), with an onset latency of 49 ms (SD 1) and 45 ms (SD 1) in midstance and late stance, respectively. Input to the vestibular apparatus (i.e., the head acceleration) occurred at a latency 10.0 ms (SD 2.4) following the drop and ankle dorsiflexion velocity was decreased starting 22 ms (SD 15) after the drop. To investigate the role of length- and velocity-sensitive afferents onthe depression in soleus muscle activity, the ankle rotation was arrested by using an ankle foot orthotic as the platform was dropped. Preventing the ankle movement did not significantly change the soleus depression in late stance [-18.2% (SD 15)], whereas the depression in midstance was removed [+4.9% (SD 13)]. It is concluded that force feedback from ankle extensors increases the locomotor output through positive feedback in late stance. In midstance the effect of force feedback was not observed, suggesting that spindle afferents may have a more significant effect on the output during this phase of the step cycle.

  6. Numerical verification of B-WIM system using reaction force signals

    International Nuclear Information System (INIS)

    Bridges are ones of fundamental facilities for roads which become social overhead capital facilities and they are designed to get safety in their life cycles. However as time passes, bridge can be damaged by changes of external force and traffic environments. Therefore, a bridge should be repaired and maintained for extending its life cycle. The working load on a bridge is one of the most important factors for safety, it should be calculated accurately. The most important load among working loads is live load by a vehicle. Thus, the travel characteristics and weight of vehicle can be useful for bridge maintenance if they were estimated with high reliability. In this study, a B-WIM system in which the bridge is used for a scale have been developed for measuring the vehicle loads without the vehicle stop. The vehicle loads can be estimated by the developed B-WIM system with the reaction responses from the supporting points. The algorithm of developed B-WIM system have been verified by numerical analysis

  7. Reaction Force/Torque Sensing in a Master-Slave Robot System without Mechanical Sensors

    Directory of Open Access Journals (Sweden)

    Kyoko Shibata

    2010-07-01

    Full Text Available In human-robot cooperative control systems, force feedback is often necessary in order to achieve high precision and high stability. Usually, traditional robot assistant systems implement force feedback using force/torque sensors. However, it is difficult to directly mount a mechanical force sensor on some working terminals, such as in applications of minimally invasive robotic surgery, micromanipulation, or in working environments exposed to radiation or high temperature. We propose a novel force sensing mechanism for implementing force feedback in a master-slave robot system with no mechanical sensors. The system consists of two identical electro-motors with the master motor powering the slave motor to interact with the environment. A bimanual coordinated training platform using the new force sensing mechanism was developed and the system was verified in experiments. Results confirm that the proposed mechanism is capable of achieving bilateral force sensing and mirror-image movements of two terminals in two reverse control directions.

  8. Measurement of the rates of reaction of the ground and metastable excited states of 02+, N0+ and 0+ with atmospheric gases at thermal energy

    International Nuclear Information System (INIS)

    Thermal-energy reaction rate coefficients and product ion distributions have been measured for reactions of both the ground state and metastable electronic states of 02+, N0+ and 0+ with several neutral species, using a selected-ion flow tube. In general the excited-ion reaction rates are fast, frequently approaching the Langevin limit. Collisional quenching occurs for the reactions of N0+sup(star) with N2,02 and H2 and the quenching rates have been determined. The ion source also provided a substantial yield of doubly charged 02 permitting some measurements of reaction rates of 022+. (author)

  9. 3D FEM Numerical Simulation of Seismic Pile-supported Bridge Structure Reaction in Liquefying Ground

    Directory of Open Access Journals (Sweden)

    Ling XianZhang, Tang Liang and Xu Pengju

    2011-04-01

    Full Text Available This study examines the establishment of liquefied ground pile-soil-bridge seismic interaction analysis of three-dimensional finite element analysis method for the simulation of liquefied ground shaking table test of pile-soil seismic interaction analysis, undertake OpenSees finite element based numerical simulation platform, for the shaking table test based on two-phase saturated porous media, Comparative numerical and experimental results, detailed test pile dynamic response of bridge structure and dynamic properties, especially liquefaction pore pressure, liquefaction of pile foundation and the dynamic response of the free field. Finite element method can reasonably predict the site of pore pressure, dynamic response; despite the conventional beam element simulation of pile, pile dynamic response can still accurately simulated.

  10. Reassessment of psychological distress and post-traumatic stress disorder in United States Air Force Distributed Common Ground System operators.

    Science.gov (United States)

    Prince, Lillian; Chappelle, Wayne L; McDonald, Kent D; Goodman, Tanya; Cowper, Sara; Thompson, William

    2015-03-01

    The goal of this study was to assess for the main sources of occupational stress, as well as self-reported symptoms of distress and post-traumatic stress disorder among U.S. Air Force (USAF) Distributed Common Ground System (DCGS) intelligence exploitation and support personnel. DCGS intelligence operators (n=1091) and nonintelligence personnel (n = 447) assigned to a USAF Intelligence, Surveillance, and Reconnaissance Wing responded to the web-based survey. The overall survey response rate was 31%. Study results revealed the most problematic stressors among DCGS intelligence personnel included high workload, low manning, as well as organizational leadership and shift work issues. Results also revealed 14.35% of DCGS intelligence operators' self-reported high levels of psychological distress (twice the rate of DCGS nonintelligence support personnel). Furthermore, 2.0% to 2.5% self-reported high levels of post-traumatic stress disorder symptoms, with no significant difference between groups. The implications of these findings are discussed along with recommendations for USAF medical and mental health providers, as well as operational leadership. PMID:25747649

  11. Influence of interfacial reaction rates on the wetting driving force in metal/ceramic systems

    Energy Technology Data Exchange (ETDEWEB)

    Landry, K. [Univ. of Wisconsin, Madison, WI (United States). Dept. of Materials Science and Engineering; Rado, C.; Eustathopoulos, N. [LTPCM-ENSEEG, Saint Martin d`Heres (France)

    1996-10-01

    The wetting of copper-silicon alloys of various compositions on vitreous carbon substrates at 1,423 K was studied by the sessile drop method. The morphology and chemistry of products of interfacial reactions between silicon and carbon were characterized by scanning electron microscopy (SEM), electron probe microanalysis, and high-resolution optical profilometry. In addition to measurements of contact angles and spreading kinetics in the reactive Cu-Si/Cv system, similar measurements were performed for the nonreactive Cu-Si/SiC system. It was found that the reaction rate has no effect on the final contact angle, which is nearly equal to the thermodynamic contact angle of the alloy on the reaction product. These findings appear to be valid for a wide range of interfacial reaction rates and for different types of interfacial reactions.

  12. Russian Military and Security Forces: A Postulated Reaction to a Nuclear Detonation

    Energy Technology Data Exchange (ETDEWEB)

    Ball, D

    2005-04-29

    In this paper, we will examine how Russia's military and security forces might react to the detonation of a 10-kiloton nuclear weapon placed next to the walls surrounding the Kremlin. At the time of this 'big bang,' Putin is situated outside Moscow and survives the explosion. No one claims responsibility for the detonation. No other information is known. Numerous variables will determine how events ultimately unfold and how the military and security forces will respond. Prior to examining these variables in greater detail, it is imperative to elucidate first what we mean by Russia's military and security forces.

  13. Repulsion forces of superplasticizers on ground granulated blast furnace slag in alkaline media, from AFM measurements to rheological properties

    Directory of Open Access Journals (Sweden)

    Palacios, M.

    2012-12-01

    Full Text Available The electrostatic and steric repulsion induced by different superplasticizers on ground granulated blast furnace slag in alkaline media have been studied. The superplasticizers were sulfonated naphthalene, sulfonated melamine, vinyl copolymer, and polycarboxylate- based admixtures. With these superplasticizers the slag suspensions had negative zeta potentials, ranging from -3 to -10 mV. For the first time the adsorbed layer thicknesses for superplasticizers on slag using colloidal probe atomic force microscopy has been measured. To model the interparticle force interactions an effective Hamaker constant was computed from dielectric properties measured on a dense slag sample produced by spark plasma sintering. The obtained results conclude that the dispersion mechanism for all the superplasticizers studied in the present work is mainly dominated by the steric repulsion. Results were then used in a yield stress model, YODEL, to predict the yield stress with and without the superplasticizers. Predictions of the yield stress agreed well with experimental results.

    En este trabajo se ha estudiado la repulsión electrostática y estérica inducida por diferentes aditivos superplastificantes en sistemas de escoria de horno alto en medios alcalinos. Se han estudiado aditivos superplastificantes basados en naftaleno, melamina, copolímeros vinílicos y basados en policarboxilato. Estos aditivos inducen en la escoria un potencial zeta negativo, entre -3 y -10 mV. Por primera vez, se ha determinado el grosor de la capa de aditivo adsorbido sobre la escoria mediante microscopía de fuerzas atómicas (AFM. Para modelizar las fuerzas de interacción entre partículas, se ha determinado la constante efectiva de Hamaker de la escoria a partir de las propiedades dieléctricas de una muestra de escoria obtenida mediante sinterización spark plasma sintering. Los resultados obtenidos concluyen que el mecanismo de dispersión de los superplastificantes estudiados en este trabajo está gobernado fundamentalmente por la repulsión estérica. Utilizando el modelo YODEL se ha podido predecir el esfuerzo de cizalla umbral de sistemas de escoria con y sin superplastificantes. Los resultados calculados están de acuerdo con los valores de esfuerzo de cizalla determinados experimentalmente.

  14. Arctic Stratus Cloud Properties and Radiative Forcing Derived from Ground-Based Data Collected at Barrow, Alaska.

    Science.gov (United States)

    Dong, Xiquan; Mace, Gerald G.

    2003-02-01

    A record of single-layer and overcast low-level Arctic stratus cloud properties has been generated using data collected from May to September 2000 at the Atmospheric Radiation Measurement (ARM) North Slope of Alaska (NSA) (71.3°N, 156.6°W) site near Barrow, Alaska. The record includes liquid-phase and liquid dominant mixed-phase Arctic stratus macrophysical, microphysical, and radiative properties, as well as surface radiation budget and cloud radiative forcing. The macrophysical properties consist of cloud fractions, cloud-base/top heights and temperatures, and cloud thickness derived from a ground-based radar and lidar pair, and rawinsonde sounding. The microphysical properties include cloud liquid water path and content, and cloud-droplet effective radius and number concentration obtained from microwave radiometer brightness temperature measurements, and the new cloud parameterization. The radiative properties contain cloud optical depth, effective solar transmission, and surface/cloud/top-of-atmosphere albedos derived from the new cloud parameterization and standard Epply precision spectral pyranometers. The shortwave, longwave, and net cloud radiative forcings at the surface are inferred from measurements by standard Epply precision spectral pyranometers and pyrgeometers. There are approximately 300 h and more than 3600 samples (5-min resolution) of single-layer and overcast low-level stratus during the study period. The 10-day averaged total and low-level cloud (Ztop < 3 km) fractions are 0.87 and 0.55, and low-level cloud-base and -top heights are around 0.4 and 0.8 km. The cloud-droplet effective radii and number concentrations in the spring are similar to midlatitude continental stratus cloud microphysical properties, and in the summer they are similar to midlatitude marine stratus clouds. The total cloud fractions in this study show good agreement with the satellite and surface results compiled from data collected during the First International Satellite Cloud Climatology Project (ISCCP) Regional Experiment (FIRE) Arctic Cloud Experiment (ACE) and the Surface Heat Budget of the Arctic Ocean (SHEBA) (77°N, 165°W) field experiments in 1998. The cloud microphysics derived from this study are similar, in general, to those collected in past field programs, although these comparisons are based on data collected at different locations and years. At the ARM NSA site, the summer cooling period is much longer (2-3 months vs 1-2 weeks), and the summer cooling magnitude is much larger (100 W m2 vs 5 W m2) than at the SHEBA ship under the conditions of all skies at the SHEBA and overcast low-level stratus clouds at the NSA site.

  15. Low forced expiratory volume is associated with blunted cardiac reactions to acute psychological stress in a community sample of middle-aged men and women

    OpenAIRE

    Carroll, D.; Phillips, A.; G.; Hunt, K; Bibbey, A.; Benzeval, M.; Ginty, A.T.

    2013-01-01

    It has been argued recently that blunted cardiovascular reactions to acute psychological stress have adverse behavioural and health corollaries that reflect dysregulation of the neural systems that support motivation. We examined the association between cardiovascular reactions to a standard stress task, the paced auditory serial arithmetic rest, and forced expiratory volume in one second, an effort, hence motivation, dependent assessment of lung function measured by spirometry. Low forced ex...

  16. Comment on "Finite Size Corrections to the Radiation Reaction Force in Classical Electrodynamics" [arXiv:1005.2617

    CERN Document Server

    Forgács, P; Kovács, P

    2012-01-01

    In [1, arXiv:1005.2617] effective field theory methods have been employed to compute the equations of motion of a spherically symmetric charged shell of radius R, taking into account the radiation reaction force exerted by the shell's own electromagnetic field up to O(R^2). The authors of Ref. [1] have stated that the known result for the self force of the shell as can be found from Eq. (16.28) of the textbook of Jackson [2] (see also Chap. 4 in the review of Pearle [3]) is incorrect, in that the term linear in R should be absent. We claim that this conclusion of Ref. [1] is incorrect, and that the textbook result, Eq. (1) does hold.

  17. In situ measurement of structural mass, stiffness, and damping using a reaction force actuator and a laser Doppler vibrometer

    International Nuclear Information System (INIS)

    The problem of structural parameter measurements needs a total solution bridging theory and experiments. In this paper, a practical methodology for in situ measurements of structural mass, stiffness, and damping is presented for built-up structures. As for the experimental uniqueness of the methodology, a reaction force actuator and non-contact optical device are utilized respectively as an input force generator and output displacement measurer, providing a fundamental data set of the proposed numerical algorithm for data-driven structural parameter estimation. The algorithm autonomously estimates the diagonalized mass, symmetric stiffness, optimal non-proportional damping, and suboptimal proportional damping matrices for multi-degrees-of-freedom structures. Structural parameter measurements of two built-up structures followed by a comparison with conventional measurements are used as examples for verification of the accuracy of the proposed methodology. (paper)

  18. Wave packet and statistical quantum calculations for the He + NeH+ ? HeH+ + Ne reaction on the ground electronic state

    International Nuclear Information System (INIS)

    A real wave packet based time-dependent method and a statistical quantum method have been used to study the He + NeH+ (v, j) reaction with the reactant in various ro-vibrational states, on a recently calculated ab initio ground state potential energy surface. Both the wave packet and statistical quantum calculations were carried out within the centrifugal sudden approximation as well as using the exact Hamiltonian. Quantum reaction probabilities exhibit dense oscillatory pattern for smaller total angular momentum values, which is a signature of resonances in a complex forming mechanism for the title reaction. Significant differences, found between exact and approximate quantum reaction cross sections, highlight the importance of inclusion of Coriolis coupling in the calculations. Statistical results are in fairly good agreement with the exact quantum results, for ground ro-vibrational states of the reactant. Vibrational excitation greatly enhances the reaction cross sections, whereas rotational excitation has relatively small effect on the reaction. The nature of the reaction cross section curves is dependent on the initial vibrational state of the reactant and is typical of a late barrier type potential energy profile

  19. Wave packet and statistical quantum calculations for the He + NeH{sup +} ? HeH{sup +} + Ne reaction on the ground electronic state

    Energy Technology Data Exchange (ETDEWEB)

    Koner, Debasish; Panda, Aditya N., E-mail: adi07@iitg.ernet.in [Department of Chemistry, Indian Institute of Technology Guwahati, Guwahati 781039 (India); Barrios, Lizandra; González-Lezana, Tomás, E-mail: t.gonzalez.lezana@csic.es [Instituto de Física Fundamental, C.S.I.C., Serrano 123, Madrid 28006 (Spain)

    2014-09-21

    A real wave packet based time-dependent method and a statistical quantum method have been used to study the He + NeH{sup +} (v, j) reaction with the reactant in various ro-vibrational states, on a recently calculated ab initio ground state potential energy surface. Both the wave packet and statistical quantum calculations were carried out within the centrifugal sudden approximation as well as using the exact Hamiltonian. Quantum reaction probabilities exhibit dense oscillatory pattern for smaller total angular momentum values, which is a signature of resonances in a complex forming mechanism for the title reaction. Significant differences, found between exact and approximate quantum reaction cross sections, highlight the importance of inclusion of Coriolis coupling in the calculations. Statistical results are in fairly good agreement with the exact quantum results, for ground ro-vibrational states of the reactant. Vibrational excitation greatly enhances the reaction cross sections, whereas rotational excitation has relatively small effect on the reaction. The nature of the reaction cross section curves is dependent on the initial vibrational state of the reactant and is typical of a late barrier type potential energy profile.

  20. Oxytocin decreases handgrip force in reaction to infant crying in females without harsh parenting experiences

    OpenAIRE

    Bakermans-kranenburg, M. J.; Ijzendoorn, M. H.; Riem, M. M. E.; Tops, M.; Alink, L. R. A.

    2011-01-01

    Infant crying can elicit sensitive caregiving as well as hostility and harsh parenting responses. In the current study (N?=?42 females) with a double-blind experimental design, we tested the effect of intranasal oxytocin administration on the use of excessive force using a hand-grip dynamometer during listening to infant cry sounds. Participants’ experiences with harsh parental discipline during childhood were found to moderate the effect of oxytocin administration on the use of excessi...

  1. Chemical reaction mechanisms in solution from brute force computational Arrhenius plots.

    Science.gov (United States)

    Kazemi, Masoud; Åqvist, Johan

    2015-01-01

    Decomposition of activation free energies of chemical reactions, into enthalpic and entropic components, can provide invaluable signatures of mechanistic pathways both in solution and in enzymes. Owing to the large number of degrees of freedom involved in such condensed-phase reactions, the extensive configurational sampling needed for reliable entropy estimates is still beyond the scope of quantum chemical calculations. Here we show, for the hydrolytic deamination of cytidine and dihydrocytidine in water, how direct computer simulations of the temperature dependence of free energy profiles can be used to extract very accurate thermodynamic activation parameters. The simulations are based on empirical valence bond models, and we demonstrate that the energetics obtained is insensitive to whether these are calibrated by quantum mechanical calculations or experimental data. The thermodynamic activation parameters are in remarkable agreement with experiment results and allow discrimination among alternative mechanisms, as well as rationalization of their different activation enthalpies and entropies. PMID:26028237

  2. Novel and Unique Expression for the Radiation Reaction Force, Relevance of Newton's Third Law and Tunneling

    OpenAIRE

    Gromes, Dieter; Thommes, Eduard

    2014-01-01

    We derive the radiation reaction by taking into account that the acceleration of the charge is caused by the interaction with some heavy source particle. In the non relativistic case this leads, in contrast to the usual approach, immediately to a result which is Galilei invariant. Simple examples show that there can be small regions of extremely low velocity where the energy requirements cannot be fulfilled, and which the charged particle can only cross by quantum mechanical...

  3. EMMI Rapid Reaction Task Force Meeting on 'Quark Matter in Compact Star'

    CERN Document Server

    Buballa, Michael; Drago, Alessandro; Fraga, Eduardo; Haensel, Pawel; Mishustin, Igor; Pagliara, Giuseppe; Schaffner-Bielich, Jurgen; Schramm, Stefan; Sedrakian, Armen; Weber, Fridolin

    2014-01-01

    The recent measurement of two solar mass pulsars has initiated an intense discussion on its impact on our understanding of the high-density matter in the cores of neutron stars. A task force meeting was held from October 7-10, 2013 at the Frankfurt Institute for Advanced Studies to address the presence of quark matter in these massive stars. During this meeting, the recent oservational astrophysical data and heavy-ion data was reviewed. The possibility of pure quark stars, hybrid stars and the nature of the QCD phase transition were discussed and their observational signals delineated.

  4. EMMI rapid reaction task force meeting on quark matter in compact stars

    International Nuclear Information System (INIS)

    The recent measurement of two solar mass pulsars has initiated an intense discussion on its impact on our understanding of the high-density matter in the cores of neutron stars. A task force meeting was held from 7–10 October 2013 at the Frankfurt Institute for Advanced Studies to address the presence of quark matter in these massive stars. During this meeting, the recent observational astrophysical data and heavy-ion data was reviewed. The possibility of pure quark stars, hybrid stars and the nature of the QCD phase transition were discussed and their observational signals delineated. (topical review)

  5. Surface aerosol radiative forcing derived from collocated ground-based radiometric observations during PRIDE, SAFARI, and ACE-Asia.

    Science.gov (United States)

    Hansell, Richard A; Tsay, Si-Chee; Ji, Qiang; Liou, K N; Ou, Szu-Cheng

    2003-09-20

    An approach is presented to estimate the surface aerosol radiative forcing by use of collocated cloud-screened narrowband spectral and thermal-offset-corrected radiometric observations during the Puerto Rico Dust Experiment 2000, South African Fire Atmosphere Research Initiative (SAFARI) 2000, and Aerosol Characterization Experiment-Asia 2001. We show that aerosol optical depths from the Multiple-Filter Rotating Shadowband Radiometer data match closely with those from the Cimel sunphotometer data for two SAFARI-2000 dates. The observed aerosol radiative forcings were interpreted on the basis of results from the Fu-Liou radiative transfer model, and, in some cases, cross checked with satellite-derived forcing parameters. Values of the aerosol radiative forcing and forcing efficiency, which quantifies the sensitivity of the surface fluxes to the aerosol optical depth, were generated on the basis of a differential technique for all three campaigns, and their scientific significance is discussed. PMID:14526843

  6. Ground-Water Hydrology and Water Quality of the Southern High Plains Aquifer, Cannon Air Force Base, Curry County, New Mexico, 1994-2005

    Science.gov (United States)

    Langman, Jeff B.; Falk, Sarah E.; Gebhardt, Fredrick E.; Blanchard, Paul J.

    2006-01-01

    In cooperation with the U.S. Air Force, the U.S. Geological Survey has collected hydrologic data about the Southern High Plains aquifer at Cannon Air Force Base in east-central New Mexico since 1994. Under the guidance of the State of New Mexico, ground-water quality of the aquifer has been analyzed as part of annual monitoring at regulated sites at the base. This report provides a summary and interpretation of all available hydrologic data collected by the U.S. Geological Survey for Cannon Air Force Base environmental managers for the regulated sites of Landfill 5 and the Sewage Lagoons between 1994 and 2005. Cannon Air Force Base is in the Southern High Plains physiographic region, and saturated deposits of the Ogallala Formation underlying the base are within the western boundary of the Southern High Plains aquifer. The general direction of ground-water flow in the Southern High Plains aquifer at Cannon Air Force Base is from northwest to southeast. In 1962, ground water predominantly flowed northwest to southeast with minimal change in direction. Ground-water altitudes declined from 1962 to 1997, and a pronounced water-level recession (area of receding water level) developed northwest of the base, altering flow direction in this area. The recession northwest of the base and the subsequent change in direction of ground-water flow are indicative of local ground-water withdrawals upgradient from Cannon Air Force Base. Historical water levels in wells within a 3-mile radius of Cannon Air Force Base declined in 52 of 56 wells for various periods of record between 1962 and 2004. Forty-three of the wells indicated strong linear decreases with time, and the largest decline was 91.80 feet, an average annual decline of about 2.13 feet per year. Water levels in monitoring wells at Cannon Air Force Base reflected the regional decline; water levels declined for all wells with periods of record greater than 1 year, and the decreases were strongly linear. From 1994 to 2005, rates of declining water levels at the base ranged from 1.45 to 1.64 feet per year near the Sewage Lagoons and from 2.24 to 4.01 feet per year near Landfill 5. The largest variation in water levels at Cannon Air Force Base was observed in wells C, D, and S, which are located adjacent to Landfill 5 near the southern boundary of the base and near an irrigation well immediately south of the base boundary. Water levels in these wells indicated a pattern of summer water-level decline followed by partial winter water-level recovery, which was likely a result of drawdown and recovery during the irrigation and nonirrigation seasons. Ground-water sampling by the U.S. Geological Survey from 1994 to 2004 at monitoring wells associated with Landfill 5 and the Sewage Lagoons indicated temporal and spatial differences in water quality. At least one anthropogenic compound was detected in each monitoring well, but all concentrations detected were small and less than U.S. Environmental Protection Agency drinking-water standards. Anthropogenic compounds detected were either pesticide or industrial compounds. Perchlorate was detected in at least one sample from every well for which perchlorate was analyzed, and the source of perchlorate is likely natural and a result of atmospheric deposition. Trace-element concentrations in raw (pretreatment) ground water at Cannon Air Force Base were generally less than drinking-water standards (applicable to posttreatment samples), but maximum concentrations of aluminum, iron, and manganese exceeded secondary drinking-water standards, and maximum chromium concentrations exceeded the primary drinking-water standard. Spatial and temporal differences of nitrate, major ions, and specific conductance indicated anthropogenic and natural influences on the Southern High Plains aquifer at Cannon Air Force Base. Larger nitrate concentrations decreased in ground water near the Sewage Lagoons during and following decommissioning of the lagoons, and c

  7. Study of the Reactions Controlling the Mobility of Uranium in Ground and Surface Water Systems in Contact with Apatite

    International Nuclear Information System (INIS)

    The objective of this project was to define the mechanisms, equilibria, kinetics, and extent of sorption of aqueous uranium onto hydroxyapatite (Ca5(PO4)3(OH)) for a range of pH, ionic strength, aqueous uranium concentration, dissolved carbon/air CO2, and mineral surface area. We conducted chemical modeling, batch and flow-through experiments, chemical analysis, x-ray absorption and diffraction measurement, and electron microscopy. Our motivation was the need to immobilize U in water and soil to prevent it's entry into water supplies and ultimately, biological systems. Applying hydroxyapatite to in-situ treatment of uranium-bearing ground water could be an effective, low cost technology. We found that hydroxyapatite quickly, effectively, and reversibly sorbed uranium at a high capacity by inner-sphere complexation over a wide range of conditions. Our results indicate that at aqueous uranium concentrations below 10-20 ppb: (1) equilibrium sorption of uranium to hydroxyapatite occurs in hours, regardless of pH; (2) in ambient and CO2-free atmospheres, over 98% of initial uranium is sorbed to hydroxyapatite, (3) in waters in equilibrium with higher air CO2 concentrations, sorption removed over 97% of aqueous uranium, except above pH 9, where aqueous uranium concentrations were reduced by less than 40%, and (4) at near-neutral pH, bicarbonate alkalinities in excess of 500 slightly retarded sorption of uraniof 500 slightly retarded sorption of uranium to hydroxyapatite, relative to lower alkalinities. Uranium sorption and precipitation are reversible and are not appreciably affected by ionic strength. The reversibility of these reactions requires that in situ treatment be carefully monitored to avoid breakthrough and de-sorption of uranium unto ground water. At typical surface conditions, sorption is the only mode of uranium sequestration below 20-50 ppb U - above this range, precipitation of uranium phosphate minerals begins to dominate sequestration processes. We verified that one m2 of hydroxyapatite can sorb over 7.53 X 10-6 moles or 1.8 mg of uranium in agreement with calculations based on phosphate and calcium oxide sites on the unit cell. Our work is significant because small masses of hydroxyapatite can sorb appreciable masses of uranium quickly over a wide range of chemistries. Preliminary work with ground water containing 260 ppb of uranium and cow bone char indicates that its sorptive capacity is appreciable less than pure hydroxyapatite. Pure crystalline hydroxyapatite sequestered 2.9 mg of uranium per m2 as opposed to 0.083 mg of uranium sequestered per m2 of cow bone char, or 27% versus 3.5% by surface area, respectively. Extended x-ray adsorption fine structure (EXAFS) spectroscopy defined mono- and bidentate sorption of uranium to phosphate and calcium oxide groups on the hydroxyapatite surface. The EXAFS data indicate that up to several thousand parts U per million parts hydroxyapatite, surface complexation, and not precipitation, is the predominant process. Above this uranium: hydroxyapatite mass ratio, precipitation of meta-autunite (H2(UO2)2(PO4)2 x 10H20) dominates the sequestration process

  8. Study of the Reactions Controlling the Mobility of Uranium in Ground and Surface Water Systems in Contact with Apatite

    Energy Technology Data Exchange (ETDEWEB)

    Taffet, M

    2004-04-22

    The objective of this project was to define the mechanisms, equilibria, kinetics, and extent of sorption of aqueous uranium onto hydroxyapatite (Ca{sub 5}(PO{sub 4}){sub 3}(OH)) for a range of pH, ionic strength, aqueous uranium concentration, dissolved carbon/air CO{sub 2}, and mineral surface area. We conducted chemical modeling, batch and flow-through experiments, chemical analysis, x-ray absorption and diffraction measurement, and electron microscopy. Our motivation was the need to immobilize U in water and soil to prevent it's entry into water supplies and ultimately, biological systems. Applying hydroxyapatite to in-situ treatment of uranium-bearing ground water could be an effective, low cost technology. We found that hydroxyapatite quickly, effectively, and reversibly sorbed uranium at a high capacity by inner-sphere complexation over a wide range of conditions. Our results indicate that at aqueous uranium concentrations below 10-20 ppb: (1) equilibrium sorption of uranium to hydroxyapatite occurs in hours, regardless of pH; (2) in ambient and CO{sub 2}-free atmospheres, over 98% of initial uranium is sorbed to hydroxyapatite, (3) in waters in equilibrium with higher air CO{sub 2} concentrations, sorption removed over 97% of aqueous uranium, except above pH 9, where aqueous uranium concentrations were reduced by less than 40%, and (4) at near-neutral pH, bicarbonate alkalinities in excess of 500 slightly retarded sorption of uranium to hydroxyapatite, relative to lower alkalinities. Uranium sorption and precipitation are reversible and are not appreciably affected by ionic strength. The reversibility of these reactions requires that in situ treatment be carefully monitored to avoid breakthrough and de-sorption of uranium unto ground water. At typical surface conditions, sorption is the only mode of uranium sequestration below 20-50 ppb U - above this range, precipitation of uranium phosphate minerals begins to dominate sequestration processes. We verified that one m{sup 2} of hydroxyapatite can sorb over 7.53 X 10{sup -6} moles or 1.8 mg of uranium in agreement with calculations based on phosphate and calcium oxide sites on the unit cell. Our work is significant because small masses of hydroxyapatite can sorb appreciable masses of uranium quickly over a wide range of chemistries. Preliminary work with ground water containing 260 ppb of uranium and cow bone char indicates that its sorptive capacity is appreciable less than pure hydroxyapatite. Pure crystalline hydroxyapatite sequestered 2.9 mg of uranium per m{sup 2} as opposed to 0.083 mg of uranium sequestered per m{sup 2} of cow bone char, or 27% versus 3.5% by surface area, respectively. Extended x-ray adsorption fine structure (EXAFS) spectroscopy defined mono- and bidentate sorption of uranium to phosphate and calcium oxide groups on the hydroxyapatite surface. The EXAFS data indicate that up to several thousand parts U per million parts hydroxyapatite, surface complexation, and not precipitation, is the predominant process. Above this uranium: hydroxyapatite mass ratio, precipitation of meta-autunite (H{sub 2}(UO{sub 2})2(PO{sub 4}){sub 2} x 10H{sub 2}0) dominates the sequestration process.

  9. Where the Lorentz-Abraham-Dirac equation for the radiation reaction force fails, and why the "proofs" break down

    CERN Document Server

    Gromes, Dieter

    2015-01-01

    We calculate the energy radiated coherently by a system of $N$ charged non relativistic particles. It disagrees with the energy loss which is obtained if one employs the Lorentz Abraham Dirac (LAD) equation for each particle, and sums up the contributions. This fact was already clearly stated in the classical literature long ago. The reason for the discrepancy is the omission of the mixing terms in the Poynting vector. For some simple systems we present a generalized equation for the radiation reaction force which cures this defect. The counter examples show that the LAD equation cannot be generally valid and that all "proofs" must fail somewhere. We demonstrate this failure for some popular examples in the literature.

  10. Progress on Light-Ion Fusion Reactions with Three-Nucleon Forces

    CERN Document Server

    Hupin, Guillaume; Langhammer, Joachim; Navrátil, Petr; Calci, Angelo; Roth, Robert

    2014-01-01

    The description of structural and dynamical properties of nuclei starting from the fundamental interaction between nucleons has been a long-standing goal in nuclear physics. The ab initio No-Core Shell Model combined with the Resonating-Group Method (NCSM/RGM) is capable of addressing both structural and reaction properties of light-nuclei. While promising results have already been achieved starting from a two-body Hamiltonian, a truly realistic prediction of nuclear observables requires the treatment of the three-nucleon interaction. Using similarity-renormalization-group evolved two- and three-nucleon interactions, we will present recent applications to n-4He scattering process when accounting for the chiral two- plus three-nucleon interaction versus the chiral two-nucleon interaction. We compare our results to phase shifts obtained from R-matrix analysis of data up to 16 MeV neutron energy, below the d-3H threshold.

  11. Progress on Light-Ion Fusion Reactions with Three-Nucleon Forces

    International Nuclear Information System (INIS)

    The description of structural and dynamical properties of nuclei starting from the fundamental interaction between nucleons has been a long-standing goal in nuclear physics. The ab initio No-Core Shell Model combined with the Resonating-Group Method (NCSM/RGM) is capable of addressing both structural and reaction properties of light-nuclei. While promising results have already been achieved starting from a two-body Hamiltonian, a truly realistic prediction of nuclear observables requires the treatment of the three-nucleon interaction. Using similarity-renormalization-group evolved two- and three-nucleon interactions, we will present recent applications to n-4He scattering process when accounting for the chiral two- plus three-nucleon interaction versus the chiral two-nucleon interaction. We compare our results to phase shifts obtained from R-matrix analysis of data up to 16 MeV neutron energy, below the d-3H threshold. (author)

  12. Humanoid Vertical Jumping based on GRF and Inertial Forces Optimization

    OpenAIRE

    Sakka, Sophie; Yokoi, Kazuhito

    2005-01-01

    This paper proposes adapting human jumping dynamics to humanoid robotic structures. Data obtained from human jumping phases and decomposition together with ground reaction forces (GRF) are used as model references. Moreover, bodies inertial forces are used as task constraints while optimizing energy to determine the humanoid robot posture and improve its jumping performances.

  13. Comparative Finite Element Analysis of the Effects of Tillage Tool Geometry on Soil Disturbance and Reaction Forces

    Directory of Open Access Journals (Sweden)

    Mohamed Ahmed Elbashir

    2014-04-01

    Full Text Available In this study a comparative finite element analysis was conducted to investigate the effects of tillage tool geometry on soil disturbance and reaction forces. A nonlinear three dimensional finite element model, using ANSYS software, was developed to study the soil cutting process by trapezoidal (T1 and rectangular (T2 flat tools that inclined to the horizontal at three rake angles (R1 = 30°, R2 = 60° and R3 = 90°, therefore a total of six treatments were considered in this analysis. The soil media was assumed as elastic-perfectly plastic material with Drucker-Prager’s model. Results of this study revealed that the maximum vertical soil displaced by T1 is greater than that of T2; hence T1 disturbed the soil better than T2 . Results also showed that a significant reduction in draft force was noticed when cutting the soil with T1 in comparison to T2 . Designing the tool in the form of T1 significantly reduces the surface area of the tool; thus conserving the engineering material.

  14. [Environmental investigation of ground water contamination at Wright- Patterson Air Force Base, Ohio]. Volume 4, Health and Safety Plan (HSP); Phase 1, Task 4 Field Investigation report: Draft

    Energy Technology Data Exchange (ETDEWEB)

    1991-10-01

    This Health and Safety Plan (HSP) was developed for the Environmental Investigation of Ground-water Contamination Investigation at Wright-Patterson Air Force Base near Dayton, Ohio, based on the projected scope of work for the Phase 1, Task 4 Field Investigation. The HSP describes hazards that may be encountered during the investigation, assesses the hazards, and indicates what type of personal protective equipment is to be used for each task performed. The HSP also addresses the medical monitoring program, decontamination procedures, air monitoring, training, site control, accident prevention, and emergency response.

  15. Depletion kinetics of the ground state CrO generated from the reaction of unsaturated Cr(CO)x with O2 and N2O

    International Nuclear Information System (INIS)

    Unsaturated Cr(CO)x(1?x?5) molecules were generated in the gas phase from photolysis of Cr(CO)6 vapor in He using an unfocussed weak UV laser pulse and their reactions with O2 and N2O have been studied. The formation and disappearance of the ground state CrO molecules were identified by monitoring laser-induced fluorescence(LIF)intensities vs delay time between the photolysis and probe pulses. The photolysis laser power dependence as well as the delay time dependence of LIF intensities from the CrO orange system showed different behavior as those from ground state Cr atoms, suggesting that the ground state CrO molecules were generated from the reaction between O2/N2O and photo- fragments of Cr(CO)6 by one photon absorption. The depletion rate constants for the ground state CrO by O2 and N2O are 5.4±0.2x10-11 and 6.5±0.4x10-12 cm3 molecule-1s-1, respectively

  16. Core particles of hepatitis B virus and ground squirrel hepatitis virus. II. Characterization of the protein kinase reaction associated with ground squirrel hepatitis virus and hepatitis B virus.

    OpenAIRE

    Feitelson, M A; Marion, P L; Robinson, W S

    1982-01-01

    The recently described protein kinase activity in hepatitis B virus core antigen particles (Albin and Robinson, J. Virol. 34:297-302, 1980) has been demonstrated here in the liver-derived core particles of ground squirrel hepatitis virus. Both protein kinase activities were initially associated with DNA polymerase-positive heavy core particles in CsCl density equilibrium gradients and shifted to polymerase-negative cores during the course of purification. The major core-associated polypeptide...

  17. Vertical force calibration of smart force platform using artificial neural networks

    Scientific Electronic Library Online (English)

    Marcelo André, Toso; Herbert Martins, Gomes.

    2014-12-01

    Full Text Available INTRODUCTION: The human body may interact with the structures and these interactions are developed through the application of contact forces, for instance due to walking movement. A structure may undergo changes in the dynamic behaviour when subjected to loads and human bodies. The aim of this paper [...] is to propose a methodology using Artificial Neural Networks (ANN) to calibrate a force platform in order to reduce uncertainties in the vertical Ground Reaction Force measurements and positioning of the applied force for the human gait. METHODS: Force platforms have been used to evaluate the pattern of applied human forces and to fit models for the interaction between pedestrians and structures. The designed force platform consists in two force plates placed side by side in the direction of walking. The reference voltages applied to the Wheatstone bridge were used for calibration as the input data to the ANN, while the output data were the estimated values of the standard weights applied to the force platform. RESULTS: It was presented a framework to enhance traditional calibration methods for force platforms (vertical component) using an ANN. The use of ANN shows significant improvements for the measured variables, leading to better results with lower uncertain values that are smaller than those using a simple traditional calibration. CONCLUSION: The results suggest that the calibration with the ANN method may be useful in obtaining more accurate vertical Ground Reaction Forces and positioning measurements in a force platform for human gait analysis.

  18. [Environmental investigation of ground water contamination at Wright-Patterson Air Force Base, Ohio]. Volume 3, Sampling and analysis plan (SAP): Phase 1, Task 4, Field Investigation: Draft

    Energy Technology Data Exchange (ETDEWEB)

    1991-10-01

    In April 1990, Wright-Patterson Air Force Base (WPAFB), initiated an investigation to evaluate a potential Comprehensive Environmental Response, Compensation, and Liability Act (CERCLA) removal action to prevent, to the extent practicable, the offsite migration of contaminated ground water from WPAFB. WPAFB retained the services of the Environmental Management Operations (EMO) and its principle subcontractor, International Technology Corporation (IT) to complete Phase 1 of the environmental investigation of ground-water contamination at WPAFB. Phase 1 of the investigation involves the short-term evaluation and potential design for a program to remove ground-water contamination that appears to be migrating across the western boundary of Area C, and across the northern boundary of Area B along Springfield Pike. Primarily, Task 4 of Phase 1 focuses on collection of information at the Area C and Springfield Pike boundaries of WPAFB. This Sampling and Analysis Plan (SAP) has been prepared to assist in completion of the Task 4 field investigation and is comprised of the Quality Assurance Project Plan (QAPP) and the Field Sampling Plan (FSP).

  19. Ground effects on USB configurations. [Upper Surface Blowing

    Science.gov (United States)

    Lan, C. E.

    1979-01-01

    Recent investigations of ground effects on aerodynamic characteristics have been stimulated by the interest in powered-lift STOL airplanes. The ground effects on upper-surface-blowing (USB) configurations may involve change in both the circulation forces and the jet reaction forces. In this note, a theoretical method is proposed for predicting these effects. It is shown that the predicted results agree well with available experimental data. In particular, the wing-alone method is shown to be incapable of predicting the ground effects of USB configurations.

  20. An experimental study on advancement of damping performance of foundations in soft ground. Pt.1: Forced vibration tests of a foundation block constructed on improved soil medium

    International Nuclear Information System (INIS)

    Purpose of this study is to enhance attenuation performance of structures that will be constructed in the soft ground area. We conducted material tests to obtain basic properties of the soil cement column. The forced vibration tests then were carried out to acquire dynamic feature of the reinforced concrete block constructed on improved soil mediums. Additional forced vibration tests for various conditions of trenches dug along the block were conducted to obtain fundamental features of damping effect of the side surfaces of the test block. According to results of the material testing, densities of the soil cement columns were 1.45-1.52 g/cm3 and the unconfined compressive strengths were 2.4-4.2 times as large as the specified design strength (1 MPa). In comparison of resonance curves by experiments and simulation analysis, simulation analysis results estimated by the hybrid approach were in good agreement with experiment ones for both the X and Y-directions. From the results of the forced vibration test focusing on various condition of the trenches dug along the test block, it was indicated that response of tamping by the rammer decreased compared with that of treading. (authors)

  1. A comparison of ground-based and space flight data: Atomic oxygen reactions with boron nitride and silicon nitride

    Science.gov (United States)

    Cross, J. B.; Lan, E. H.; Smith, C. A.; Whatley, W. J.; Koontz, S. L.

    The effects of atomic oxygen on boron nitride (BN) and silicon nitride (Si3N4) have been studied in low Earth orbit (LEO) flight experiments and in a ground-based simulation facility at Los Alamos National Laboratory. Both the in-flight and ground-based experiments employed the materials coated over thin (approx 250 Angstrom) silver films whose electrical resistance was measured in situ to detect penetration of atomic oxygen through the BN and Si3N4 materials. In the presence of atomic oxygen, silver oxidizes to form silver oxide, which has a much higher electrical resistance than pure silver. Permeation of atomic oxygen through BN, as indicated by an increase in the electrical resistance of the silver underneath, was observed in both the in-flight and ground-based experiments. In contrast, no permeation of atomic oxygen through Si3N4 was observed in either the in-flight or ground-based experiments. The ground-based results show good qualitative correlation with the LEO flight results, thus validating the simulation fidelity of the ground-based facility in terms of reproducing LEO flight results.

  2. Analytical results from ground-water sampling using a direct-push technique at the Dover National Test Site, Dover Air Force Base, Delaware, June-July 2001

    Science.gov (United States)

    Guertal, William R.; Stewart, Marie; Barbaro, Jeffrey R.; McHale, Timthoy J.

    2004-01-01

    A joint study by the Dover National Test Site and the U.S. Geological Survey was conducted from June 27 through July 18, 2001 to determine the spatial distribution of the gasoline oxygenate additive methyl tert-butyl ether and selected water-quality constituents in the surficial aquifer underlying the Dover National Test Site at Dover Air Force Base, Delaware. The study was conducted to support a planned enhanced bio-remediation demonstration and to assist the Dover National Test Site in identifying possible locations for future methyl tert-butyl ether remediation demonstrations. This report presents the analytical results from ground-water samples collected during the direct-push ground-water sampling study. A direct-push drill rig was used to quickly collect 115 ground-water samples over a large area at varying depths. The ground-water samples and associated quality-control samples were analyzed for volatile organic compounds and methyl tert-butyl ether by the Dover National Test Site analytical laboratory. Volatile organic compounds were above the method reporting limits in 59 of the 115 ground-water samples. The concentrations ranged from below detection limits to maximum values of 12.4 micrograms per liter of cis-1,2-dichloroethene, 1.14 micrograms per liter of trichloroethene, 2.65 micrograms per liter of tetrachloroethene, 1,070 micrograms per liter of methyl tert-butyl ether, 4.36 micrograms per liter of benzene, and 1.8 micrograms per liter of toluene. Vinyl chloride, ethylbenzene, p,m-xylene, and o-xylene were not detected in any of the samples collected during this investigation. Methyl tert-butyl ether was detected in 47 of the 115 ground-water samples. The highest methyl tert-butyl ether concentrations were found in the surficial aquifer from -4.6 to 6.4 feet mean sea level, however, methyl tert-butyl ether was detected as deep as -9.5 feet mean sea level. Increased methane concentrations and decreased dissolved oxygen concentrations were found in samples that contained methyl tert-butyl ether.

  3. Large-eddy simulation of pollutant dispersion from a ground-level area source over urban street canyons with irreversible chemical reactions

    Science.gov (United States)

    Du, T. Z.; Liu, C.-H.; Zhao, Y. B.

    2014-10-01

    In this study, the dispersion of chemically reactive pollutants is calculated by large-eddy simulation (LES) in a neutrally stratified urban canopy layer (UCL) over urban areas. As a pilot attempt, idealized street canyons of unity building-height-to-street-width (aspect) ratio are used. Nitric oxide (NO) is emitted from the ground surface of the first street canyon into the domain doped with ozone (O3). In the absence of ultraviolet radiation, this irreversible chemistry produces nitrogen dioxide (NO2), developing a reactive plume over the rough urban surface. A range of timescales of turbulence and chemistry are utilized to examine the mechanism of turbulent mixing and chemical reactions in the UCL. The Damköhler number (Da) and the reaction rate (r) are analyzed along the vertical direction on the plane normal to the prevailing flow at 10 m after the source. The maximum reaction rate peaks at an elevation where Damköhler number Da is equal or close to unity. Hence, comparable timescales of turbulence and reaction could enhance the chemical reactions in the plume.

  4. Effects of the tensor force on the ground and first $2^{+}$ states of the magic $^{54}$Ca nucleus

    OpenAIRE

    Yüksel, E.; Van Giai, N.; Khan, E; Bozkurt, K.

    2014-01-01

    The magic nature of the $^{54}$Ca nucleus is investigated in the light of the recent experimental results. We employ both HFB and HF+BCS methods using Skyrme-type SLy5, SLy5+T and T44 interactions. The evolution of the single-particle spectra is studied for the N=34 isotones: $^{60}$Fe, $^{58}$Cr, $^{56}$Ti and $^{54}$Ca. An increase is obtained in the neutron spin-orbit splittings of $p$ and $f$ states due to the effect of the tensor force which also makes $^{54}$Ca a magic...

  5. Effects of the tensor force on the ground state and first 2+ states of the magic Ca54 nucleus

    Science.gov (United States)

    Yüksel, E.; Van Giai, N.; Khan, E.; Bozkurt, K.

    2014-06-01

    The magic nature of the Ca54 nucleus is investigated in light of recent experimental results. We employ both Hartree-Fock-Bogoliubov and Hartree-Fock (HF)+BCS methods using Skyrme-type SLy5, SLy5+T, and T44 interactions. The evolution of the single-particle spectra is studied for the N =34 isotones: Fe60, Cr58, Ti56, and Ca54. An increase is obtained in the neutron spin-orbit splittings of p and f states due to the effect of the tensor force which also makes Ca54 a magic nucleus candidate. Quasiparticle random-phase approximation calculations on top of HF+BCS are performed to investigate the first J?=2+ states of the calcium isotopic chain. A good agreement for excitation energies is obtained when we include the tensor force in the mean-field part of the calculations. The first 2+ states indicate a subshell closure for both Ca52 and Ca54 nuclei. We confirm that the tensor part of the interaction is quite essential in explaining the neutron subshell closure in Ca52 and Ca54 nuclei.

  6. Effects of the tensor force on the ground and first $2^{+}$ states of the magic $^{54}$Ca nucleus

    CERN Document Server

    Yüksel, E; Khan, E; Bozkurt, K

    2014-01-01

    The magic nature of the $^{54}$Ca nucleus is investigated in the light of the recent experimental results. We employ both HFB and HF+BCS methods using Skyrme-type SLy5, SLy5+T and T44 interactions. The evolution of the single-particle spectra is studied for the N=34 isotones: $^{60}$Fe, $^{58}$Cr, $^{56}$Ti and $^{54}$Ca. An increase is obtained in the neutron spin-orbit splittings of $p$ and $f$ states due to the effect of the tensor force which also makes $^{54}$Ca a magic nucleus candidate. QRPA calculations on top of HF+BCS are performed to investigate the first $J^{\\pi}$=$2^{+}$ states of the calcium isotopic chain. A good agreement for excitation energies is obtained when we include the tensor force in the mean-field part of the calculations. The first $2^{+}$ states indicate a subshell closure for both $^{52}$Ca and $^{54}$Ca nuclei. We confirm that the tensor part of the interaction is quite essential in explaining the neutron subshell closure in $^{52}$Ca and $^{54}$Ca nuclei.

  7. Internal radiation exposure of Ground Self-Defense Force members involved in the management of the Fukushima Nuclear Power Plant disaster.

    Science.gov (United States)

    Naoi, Yutaka; Fujikawa, Akira; Kyoto, Yukishige; Kunishima, Naoaki; Ono, Masahiro; Watanabe, Yukie

    2013-01-01

    When the Great East Japan Earthquake occurred on March 11, 2011, the Ground Self-Defense Force (GSDF) was dispatched nationally to Northeast area in Japan. The highly trained GSDF members were simultaneously assigned to various missions for the Fukushima Nuclear Power Plants disaster. The missions of GSDF terminated on August 31, 2011. Special medical examinations were conducted for the members as they returned to each military unit. GSDF members who were assigned to the nuclear power plant were at risk of radiation exposure; therefore, pocket dosimeters were used to assess external radiation exposure. A few months after the mission was terminated, measurements of internal radiation exposure were performed. This is the first report of the internal exposure of GSDF members who worked in the restricted radiation contamination area. Here, we report the amounts of internal and external exposure of and the equipment used by the GSDF members. PMID:24352931

  8. 2H(p, pp) n reaction as a probe of the short-range nuclear force

    International Nuclear Information System (INIS)

    We examine the feasibility of using the 2H(p, pp) n reaction as a means of extracting information about the short-range behavior of the nuclear force not obtainable from N-N scattering experiments. To do this we use several separable potentials and examine the predicted cross section in various regions of phase space and for beam energies between 14 and 65 MeV. The questions that we address are likely to be insensitive to Coulomb effects. Both the form factor and the energy dependence of the potentials have been modified from the usual Yamaguchi form. The form of the energy dependence is chosen to obtain phase-shift equivalence for two different form factors while guaranteeing a unitary two-body scattering amplitude. The sensitivity of breakup results to the on-shell and off-shell aspects of the nuclear force is examined and discussed. Significant on-shell sensitivity occurs for breakup amplitudes in all states and for cross sections over all regions of phase space. Off-shell sensitivity appears only in the S = 1/2, L = 0 breakup amplitudes, with all S = 3/2 and all L > 0 amplitudes exhibiting negligible off-shell dependence. This result leads to only a very small (< or = 5%) off-shell sensitivity for quasifree scattering. However, cross sections far from quasifree scattering, and in particular cross sections in the final-state interaction region of phase space, exhibit as much as a 50% variation for phase-shift-equivalent potentials. This sensitivity is smivalent potentials. This sensitivity is small at low beam energy and increases with increasing energy. The energy dependence at negative energies of one potential is also altered to adjust the triton binding energy. This enables us to compare phase-shift-equivalent potentials differing off shell but predicting the same triton binding energy. The energy dependence of this potential is somewhat unconventional. Fixing of the triton binding energy reduces the off-shell sensitivity appreciably only for E approximately-less-than 20 MeV

  9. Aerodynamic Lifting Force.

    Science.gov (United States)

    Weltner, Klaus

    1990-01-01

    Describes some experiments showing both qualitatively and quantitatively that aerodynamic lift is a reaction force. Demonstrates reaction forces caused by the acceleration of an airstream and the deflection of an airstream. Provides pictures of demonstration apparatus and mathematical expressions. (YP)

  10. Nuclear ground-state properties and nuclear forces in the unitary-model-operator approach: Application to /sup 16/O

    International Nuclear Information System (INIS)

    A formulation is given to derive an effective interaction in the framework of the unitary-model-operator approach. A unitary transformation is introduced to describe two-body correlations and is determined from the condition that the effective interaction should be decoupled between the low- and high-momentum spaces. A unitary transformation of the Hamiltonian is made and the transformed Hamiltonian is represented in a cluster-expansion form. The effective interaction thus defined is E independent and Hermitian. The contributions of one-, two-, and three-body-cluster terms are taken into consideration. The self-consistent single-particle potential is considered sym- metrically for both occupied (hole) and unoccupied (particle) states. The theory is applied to the calculation of the ground-state properties of /sup 16/O using three potentials, namely, the Paris, Reid soft-core, and supersoft-core potentials. A large gain in the binding energy is obtained. Final results for the gound-state energy and the charge radius are as follows: -119.2 MeV and 2.62 fm for the Paris, -115.1 MeV and 2.60 fm for the Reid soft core, and -121.7 MeV and 2.62 fm for the supersoft core. The single-particle energies of the occupied orbits are also calculated. Good agreement between the calculated and experimental energies is obtained. In particular, a large spin-orbit splitting of the 0p orbits is reproduced with the results 5.6 MeV for the Paris, 5.1 MeV for the Reid soft core, and 5.4 MeV 1 MeV for the Reid soft core, and 5.4 MeV for the supersoft core, which should be compared with the experimental value 6.1 MeV

  11. Estimation of the aerosol radiative forcing at ground level, over land, and in cloudless atmosphere, from METEOSAT-7 observation: method and case study

    Directory of Open Access Journals (Sweden)

    T. Elias

    2008-02-01

    Full Text Available A new method is proposed to estimate the spatial and temporal variability of the solar radiative flux reaching the surface over land (DSSF, as well as the Aerosol Radiative Forcing (ARF, in cloud-free atmosphere. The objective of regional applications of the method is attainable by using the visible broadband of METEOSAT-7 satellite instrument which scans Europe and Africa on a half-hourly basis. The method relies on a selection of best correspondence between METEOSAT-7 radiance and radiative transfer computations.

    The validation of DSSF is performed comparing retrievals with ground-based measurements acquired in two contrasted environments: an urban site near Paris and a continental background site located South East of France. The study is concentrated on aerosol episodes occurring around the 2003 summer heat wave, providing 42 cases of comparison for variable solar zenith angle (from 59° to 69°, variable aerosol type (biomass burning emissions and urban pollution, and variable aerosol optical thickness (a factor 6 in magnitude. The method reproduces measurements of DSSF within an accuracy assessment of 20 W m?2 (5% in relative in 70% of the situations, and within 40 W m?2 in 90% of the situations, for the two case studies considered here.

    Considering aerosol is the main contributor in changing the measured radiance at the top of the atmosphere, DSSF temporal variability is assumed to be caused only by aerosols, and consequently ARF at ground level and over land is also retrieved: ARF is computed as the difference between DSSF and a parameterised aerosol-free reference level. Retrievals are linearly correlated with the ground-based measurements of the aerosol optical thickness (AOT: sensitivity is included between 120 and 160 W m?2 per unity of AOT at 440 nm. AOT being an instantaneous measure indicative of the aerosol columnar amount, we prove the feasibility to infer instantaneous aerosol radiative impact at the ground level over land with METEOSAT-7 visible channel.

  12. Estimation of the aerosol radiative forcing at ground level, over land, and in cloudless atmosphere, from METEOSAT-7 observation: method and first results

    Directory of Open Access Journals (Sweden)

    T. Elias

    2007-09-01

    Full Text Available A new method is proposed to estimate the spatial and temporal variability of the solar radiative flux reaching the surface (DSSF over land, as well as the Aerosol Radiative Forcing (ARF, in cloud-free atmosphere. The objective of global applications of the method is fulfilled by using the visible broadband of METEOSAT-7 satellite which scans Europe and Africa on a half-hourly basis. The method relies on a selection of best correspondence between METEOSAT-7 radiance and DSSF computed with a radiative transfer code.

    The validation of DSSF is performed comparing retrievals with ground-based measurements acquired in two contrasted environments, i.e. an urban site near Paris and a continental background site in South East of France. The study is concentrated on aerosol episodes occurring around the 2003 summer heat wave, providing 42 cases of comparison for variable solar zenith angle (from 59° to 69°, variable aerosol type (biomass burning emissions and urban pollution, and variable aerosol optical thickness (a factor 6. The method reproduces measurements of DSSF within an accuracy assessment of 20 Wm?2 (5% in relative in 70% of the cases, and within 40 Wm?2 in 90% of the cases.

    Considering aerosol is the main contributor in changing the measured radiance at the top of the atmosphere, DSSF temporal variability is assumed to be caused only by aerosols, and consequently the ARF at ground level and over land is also retrieved: ARF is computed as the difference between DSSF and a parameterised aerosol-free reference level. Retrievals are linearly correlated with the ground-based measurements of the aerosol optical thickness (AOT: sensitivity is included between 120 and 160 Wm?2 per unity of AOT at 440 nm. AOT being an instantaneous measure indicative of the aerosol columnar amount, we therefore prove the feasibility to infer instantaneous aerosol radiative impact at the ground level over land with METEOSAT-7 visible channel.

  13. Runners do not push off the ground but fall forwards via a gravitational torque.

    Science.gov (United States)

    Romanov, Nicholas; Fletcher, Graham

    2007-09-01

    The relationship between the affect and timing of the four forces involved in running (gravity, ground reaction force, muscle force, and potential strain energy) is presented. These forces only increase horizontal acceleration of the centre of mass during stance but not flight. The current hierarchical models of running are critiqued because they do not show gravity, a constant force, in affect during stance. A new gravitational model of running is developed, which shows gravity as the motive force. Gravity is shown to cause a torque as the runner's centre of mass moves forward of the support foot. Ground reaction force is not a motive force but operates according to Newton's third law; therefore, the ground can only propel a runner forward in combination with muscle activity. However, leg and hip extensor muscles have consistently proven to be silent during leg extension (mid-terminal stance). Instead, high muscle-tendon forces at terminal stance suggest elastic recoil regains most of the centre of mass's height. Therefore, the only external motive force from mid-terminal stance is gravity via a gravitational torque, which causes a horizontal displacement. The aim of this paper is to establish a definitive biomechanical technique (Pose method) that is easily taught to runners (Romanov, 2002): falling forwards via a gravitational torque while pulling the support foot rapidly from the ground using the hamstring muscles. PMID:17933203

  14. Reaction of electric and meteorological states of the near-ground atmosphere during a geomagnetic storm on 5 April 2010

    Science.gov (United States)

    Smirnov, Sergey

    2014-12-01

    The effects of a geomagnetic storm on 5 April 2010 on electric parameters of the atmospheric near-ground layer in Kamchatka have been investigated. Three processes over the course of the storm were identified. Air electroconductivity began to decrease 4 h before the storm, and this lasted for 20 h. The storm's sudden commencement caused potential gradient oscillations with amplitudes up to 300 V/m. During the stages of the storm, a significant increase in the atmosphere ion content unipolarity coefficient occurred.

  15. Surface reactions of vapor phase titanium atoms with halogen and nitrogen containing polymers studied using in situ X-ray photoelectron spectroscopy and atomic force microscopy

    Science.gov (United States)

    Carlo, S. R.; Perry, C. C.; Torres, Jessica; Wagner, A. J.; Vecitis, C.; Fairbrother, D. Howard

    2002-07-01

    The surface reactions of vapor phase Ti with polytetrafluorethylene (PTFE), polyvinylchloride (PVC) and nitrogen-modified polyethylene (PE) have been studied using in situ X-ray photoelectron spectroscopy (XPS) and ex situ atomic force microscopy (AFM). Titanium reactions with PTFE and PVC surfaces lead to the simultaneous formation of a titanium halide salt and TiC. Titanium reactions with both PTFE and PVC also produced significant morphological changes at the polymer surface. During Ti metallization of PTFE, defluorination did not produce any CF or CF 3 species normally observed during defluorination reactions of metal atoms with PTFE. The amount of titanium fluoride present at the metal-polymer interface was enhanced by post-metallization X-ray irradiation. Results on the Ti surface reactions are also compared and contrasted with Fe and Cu reactivity with PTFE and PVC. The reactions of Ti with nitrogen-modified PE lead to the simultaneous formation of TiN and TiC. Experimental evidence, however, suggests that the different nitrogen containing functional groups present in the nitrogen-modified PE were not equally reactive towards Ti metallization.

  16. Solar energy assessment in the Alpine area: satellite data and ground instruments integration for studying the radiative forcing of aerosols.

    Science.gov (United States)

    Castelli, M.; Petitta, M.; Emili, E.

    2012-04-01

    The primary objective of this work is to purpose an approach for estimating the effect of aerosols on surface incoming shortwave radiation (SIS) in the Alpine region, which is based on the integration of different instruments: we develop a GIS model, whose output is corrected by monthly atmospheric coefficients, and then we progressively add details by daily updated atmospheric information. The assessment of solar energy availability at the earth's surface over a specific geographic area is crucial for planning photovoltaic panels installation. When modeling SIS with GIS instruments or retrieving it from satellites measurements, we have to account for terrain shadowing and atmospheric extinction, both of which are difficult to describe in the Alpine area, because of the topographic complexity and the local atmospheric circulation influence on the atmospheric composition. While advanced methods were developed to carefully describe the effect of topography, the atmospheric attenuation was considered so far only through monthly turbidity values, and the question remains whether it be possible to develop a time-effective routine to model the atmospheric effect on SIS at daily scale. As a first step we produced a WebGIS for the town of Bressanone, Italy, showing a classification of the roofs of the buildings according to the yearly amount of global irradiance. Furthermore we provide the annual electricity production based on the efficiency of the most common PV technologies. At this stage clear sky irradiance was computed with a GIS based model, and afterwards monthly correction coefficients were applied to add real sky conditions to the merely geometrical computations, which were obtained from 20 years of measurement collected by the pyranometer in the closest meteorological station. As a second step we investigate the influence of aerosol optical properties on SIS by running the radiative transfer model libRadtran by using as input the aerosol model defined for the measurement site of Bolzano, where we installed an AERONET sun-photometer for measuring aerosol optical properties and column water-vapor amount. The impact of aerosols on the surface irradiance was already demonstrated, in fact the literature shows that the daily aerosol direct forcing on the surface radiation in the Italian Po valley amounts on average to -12.2 Wm-2, with extremes values beyond -70 Wm-2. In particular here we examine the role in the radiation budget of the Alpine valleys of aerosol microphysical characteristics, such as size distribution, and optical properties, such as phase function, derived from the inversion of spectrally resolved sky radiances. After provided evidence of the radiative impact of atmospheric aerosols on solar energy availability in the Alpine area, the final step will be the enhancement of the most advanced existent algorithm for retrieving SIS in the Alpine area from satellite data, developed by MeteoSwiss in the framework of CM-SAF, which thoroughly considers the effect of topography and clouds, while can still be improved in terms of atmospheric input data.

  17. Ground-state correlations in 12C and the mechanism of the (e,e'p) reaction

    International Nuclear Information System (INIS)

    In this thesis the results of an investigation into two aspects of the mechanism of the quasi-elastic (e,e'p) reaction: the interaction between the incident electron and the bound proton and the residual nucleus (final-state interaction (FSI)), are presented and used in the extraction of nuclear-structure information from (e,e'p) measurements on 12C. The experiments were carried out at NIKHEF-K with a high-resolution spectrometer. Two kinds of experiments have been performed on 12C. The first was aimed at obtaining accurate momentum distributions for various final states in 11B. Some special measurements were carried out in order to vary the parameters influencing the FSI. The role of coupled-channels effects in the 12C(e,e'p)11Be reaction is discussed. It is discussed whether some of the weak transitions observed in this reaction, can be associated with knockout from normally unoccupied shell-model orbitals. The second experiment on 12C was devoted to the e-p coupling. These measurements were supplemented with data taken on 6Li. The latter measurement allowed for measuring simultaneously knockout from the relatively dense 4He core and the relatively dilute deuteron. In this way the density dependence of the e-p coupling in the nucleus could be studied. The results of these experiments have been compared to various models that take into account the effect of the nuclear medium upon the e-p coupling. The possible role of charge-exchange and meson-exchange currents in the interpretation of these experiments is also considered. A brief survey of the formalism of the quasi-elastic (e,e'p) reaction is also presented. (author). 196 refs.; 53 figs.; 21 tabs

  18. The Ground Axiom (GA)

    OpenAIRE

    Reitz, Jonas

    2006-01-01

    A new axiom is proposed, the Ground Axiom, asserting that the universe is not a nontrivial set forcing extension of any inner model. The Ground Axiom is first-order expressible, and any model of ZFC has a class forcing extension which satisfies it. The Ground Axiom is independent of many well-known set-theoretic assertions including the Generalized Continuum Hypothesis, the assertion V=HOD that every set is ordinal definable, and the existence of measurable and supercompact ...

  19. Diffusion and reactivity of ground-state nitrogen atoms N(4S) between 3 and 15 K: application to the hydrogen abstraction reaction from methane under non-energetic conditions

    Science.gov (United States)

    Nourry, Sendres; Krim, Lahouari

    2015-07-01

    We have characterized the CH4 + N(4S) reaction in solid phase, at very low temperature, under non-energetic conditions and where the CH4 and N reactants are in their ground states. A microwave-driven atomic source has been used to generate ground-state nitrogen atoms N(4S), and experiments have been carried out at temperatures as low as 3 K to reduce the mobility of the trapped species in solid phase and hence to freeze the first step of the CH4 + N reaction pathway. Leaving the formed solid sample in the dark for a while allows all trapped reactants to relax to the ground state, specifically radicals and excited species streaming from the plasma discharge. Such a method could be the only possibility of proving that the CH4 + N reaction occurs between CH4 and N reactants in their ground states without any additional energy to initiate the chemical process. The appearance of the CH3 reaction product, just by inducing the mobility of N atoms between 3 and 11 K, translates that a hydrogen abstraction reaction from methane, under non-energetic conditions, will start occurring at very low temperature. The formation of methyl radical, under these experimental conditions, is due to recombination processes N(4S)-N(4S) of ground-state nitrogen atoms without any contribution of cosmic ray particles or high-energy photons.

  20. Effect of an external electric field on the diffusion-influenced geminate reversible reaction of a neutral particle and a charged particle in three dimensions. III. Ground-state ABCD reaction

    Science.gov (United States)

    Reigh, Shang Yik

    2013-11-01

    In the presence of an external electric field, the ground-state A+B^q rightleftharpoons C^q + D diffusion-influenced reversible reaction for a geminate pair, a neutral and a charged particle, is investigated in three dimensions. The probability density functions, the rates of reactions, and the survival probabilities of individual particles are analytically derived in the Laplace domain in terms of series solutions. The long-time kinetics of probability density functions and rates of reactions in rescaled forms shows a kinetic transition behavior from a t-3/2 power law to a t-3/2et increase when the condition D_1F_1^2 ? D_2F_2^2, which depends on the diffusivities of particles and the external electric fields, changes to D_1F_1^2 > D_2F_2^2. In the transition region D_1F_1^2 = D_2F_2^2, the long-time behavior also shows a t-3/2 power law decay but with a different value of the prefactor. The rescaled survival probabilities only exhibit an exponentially increasing behavior at long times with no dependence on the various values of parameters.

  1. Measurement of the ground-state gamma-ray branching ratio of the dt reaction at low energies

    International Nuclear Information System (INIS)

    The branching ratio GAMMA/sub gamma0//GAMMA/sub ?/ for the d+t reaction has been measured between deuteron energies of 45 and 146 keV. Pair-coincidence spectrometry and pulse-shape discrimination were employed to reduce the neutron effects in the NaI(Tl) gamma-ray detector. The branching ratio is found to be constant over the energy range of the measurements with a best value GAMMA/sub ?/0/GAMMA/sub ?/ = (5.4 +- 1.3) x 10-5. This value is significantly greater than cluster-model calculations of the branching ratio

  2. A global ab initio potential energy surface for the X{sup ?2}A{sup ?} ground state of the Si + OH ? SiO + H reaction

    Energy Technology Data Exchange (ETDEWEB)

    Dayou, Fabrice, E-mail: fabrice.dayou@obspm.fr [Laboratoire d' Etude du Rayonnement et de la Matière en Astrophysique (UMR 8112 du CNRS), Observatoire de Paris-Meudon, Université Pierre et Marie Curie, 92195 Meudon Cedex (France); Duflot, Denis; Rivero-Santamaría, Alejandro; Monnerville, Maurice [Laboratoire de Physique des Lasers, Atomes et Molécules (UMR 8523 du CNRS), Université Lille I Sciences et Technologies, 59655 Villeneuve d' Ascq Cedex (France)

    2013-11-28

    We report the first global potential energy surface (PES) for the X{sup ?2}A{sup ?} ground electronic state of the Si({sup 3}P) + OH(X{sup 2}?) ? SiO(X{sup 1}?{sub g}{sup +}) + H({sup 2}S) reaction. The PES is based on a large number of ab initio energies obtained from multireference configuration interaction calculations plus Davidson correction (MRCI+Q) using basis sets of quadruple zeta quality. Corrections were applied to the ab initio energies in the reactant channel allowing a proper description of long-range interactions between Si({sup 3}P) and OH(X{sup 2}?). An analytical representation of the global PES has been developed by means of the reproducing kernel Hilbert space method. The reaction is found barrierless. Two minima, corresponding to the SiOH and HSiO isomers, and six saddle points, among which the isomerization transition state, have been characterized on the PES. The vibrational spectra of the SiOH/HSiO radicals have been computed from second-order perturbation theory and quantum dynamics methods. The structural, energetic, and spectroscopic properties of the two isomers are in good agreement with experimental data and previous high quality calculations.

  3. Confining forces

    CERN Document Server

    Rollmann, Dirk

    2015-01-01

    We discuss the forces on the internal constituents of the hadrons based on the bag model. The ground state of the hadrons forms a color singlet so that the effects of the colored internal states are neutralized. From the breaking of the dilatation and conformal symmetries under the strong interactions the corresponding currents are not conserved. These currents give rise to the forces changing the motion of the internal particles which causes confinement.

  4. Electron-transfer reactions involving two harmonic potentials with a different force constant: The Zusman approach versus the spin-boson model

    International Nuclear Information System (INIS)

    Two approaches: (a generalized spin-boson model with a nonlinear spin-boson coupling and the Zusman's stochastic Liouville formalism) are employed to analyze the electron-transfer reactions involving two harmonic potentials with a different force constant. An analytical rate formula, expressed as a convoluted integral of the individual rate kernel for each mode, is derived with full consideration of quantum tunneling effects. For a dominant solvent mode at low frequency, the formula can be reduced to the results of the Zusman's theory, showing asymmetry of the Marcus rate plot between the normal and the inverted regions

  5. The gravitational radiation reaction force of a continuous medium. II. Perturbation of a quasi-minkowskian motion

    International Nuclear Information System (INIS)

    We determine, within the framework of the first approximation of general relativity, the equations of motion of a continuous medium in which the forces from material stresses play a leading part with respect to the gravitational forces. In the slow approximation, we deduce the formula for the variation of the energy of the system due to the gravitational radiation. We obtain the surprising result that it has exactly the same form that one determined in the preceding paper (not only when averaged over a quasi-periodic motion)

  6. Guideline on the investigation and management of acute transfusion reactions. Prepared by the BCSH Blood Transfusion Task Force.

    Science.gov (United States)

    Tinegate, Hazel; Birchall, Janet; Gray, Alexandra; Haggas, Richard; Massey, Edwin; Norfolk, Derek; Pinchon, Deborah; Sewell, Carrock; Wells, Angus; Allard, Shubha

    2012-10-01

    Although acute non-haemolytic febrile or allergic reactions (ATRs) are a common complication of transfusion and often result in little or no morbidity, prompt recognition and management are essential. The serious hazards of transfusion haemovigilance organisation (SHOT) receives 30-40 reports of anaphylactic reactions each year. Other serious complications of transfusion, such as acute haemolysis, bacterial contamination, transfusion-related acute lung injury (TRALI) or transfusion-associated circulatory overload (TACO) may present with similar clinical features to ATR. This guideline describes the approach to a patient developing adverse symptoms and signs related to transfusion, including initial recognition, establishing a likely cause, treatment, investigations, planning future transfusion and reporting within the hospital and to haemovigilance organisations. Key recommendations are that adrenaline should be used as first line treatment of anaphylaxis, and that transfusions should only be carried out where patients can be directly observed and where staff are trained in manging complications of transfusion, particularly anaphylaxis. Management of ATRs is not dependent on classification but should be guided by symptoms and signs. Patients who have experienced an anaphylactic reaction should be discussed with an allergist or immunologist, in keeping with UK resuscitation council guidelines. PMID:22928769

  7. Lesiones de los sargentos alumnos del Ejército de Tierra y factores de riesgo lesional / Injuries of the Ground Forces Student Sergeants and injury risk factors

    Scientific Electronic Library Online (English)

    F.A., Valero Capilla; L., Franco Bonafonte; F.J., Rubio Pérez.

    2014-12-01

    Full Text Available Antecedentes: los cursos de entrenamiento militar requieren un alto nivel de exigencia física y provocan un número importante de lesiones osteomusculares. Es de interés conocer el tipo de lesiones que se observan en estos cursos y los factores de riesgo lesional asociados, para poder implantar poste [...] riormente medidas preventivas adecuadas y correctas gestiones de los recursos que se disponen. Objetivo: presentar el tipo de lesiones observadas durante la fase común del primer curso de formación de los sargentos alumnos del Ejército de Tierra (ET) y analizar la frecuencia lesional y factores de riesgo relacionados. Material y Métodos: estudio descriptivo observacional de corte transversal de 15 semanas de duración, en el que se incluyeron 579 sargentos alumnos (49 mujeres), edad media de 25,9 años (Rango 18-31). Al inicio del curso, se obtuvieron los parámetros antropométricos de los alumnos y se midió su condición física mediante las marcas obtenidas en carrera de 6000, 1000 y 50 m, y pruebas de salto vertical y flexo extensiones en suelo. Durante el curso, se registraron las lesiones observadas, sus causas, localización y tiempo de recuperación. Al final del curso, se comparó la frecuencia lesional observada y sus causas entre hombres y mujeres, y en el grupo de hombres, se compararon las marcas obtenidas y los parámetros antropométricos entre los lesionados y no lesionados. Resultados: la edad media del grupo de mujeres vs hombres fue de 27,1 (3,18) vs 25,7 (3,03) años p Abstract in english Background: military training courses are very physically demanding and they cause a significant number of musculoskeletal injuries. It is of interest to know the type of injuries observed in these courses and the associated injury risk factors in order to subsequently implant appropriate preventive [...] measures and manage available resources. Objective: to present the type of injuries observed during the common phase of the first training course of the Ground Forces Student Sergeants and to analyze the frequency of injuries and related risk factors. Material and Methods: descriptive, observational, cross-sectional, 15 week duration study, which included 579 student sergeants (49 women), average age of 25.9 years (range 18-31). At the beginning of the course, the anthropometric parameters of students were obtained and their physical condition was measured through the marks obtained in 6000, 1000 and 50 m career, and through vertical jump and flexion/extension tests on the ground. During the course, observed injuries, their causes, location and recovery time were recorded. At the end of the course, the observed frequency of injuries and their causes were compared between men and women, and in the male group, the obtained marks and the anthropometric parameters were compared between the injured and not injured. Results: the average age of the women vs men´s group was 27.1 (3.18) vs. 25.7 (3.03) years p

  8. The brute-force polarization of 23Na and the 23Na(n,?)24Na reaction

    International Nuclear Information System (INIS)

    A Na target has been polarized by brute force to 22% and the ? radiation produced by polarized thermal neutron capture has been investigated. The 2+ channel spin contribution has been determined model independently and unambiguously for 22 primary transitions. The average 2+ channel contribution is 5.8(5)%. Spins of final levels are in agreement with previous assignments. For three levels spin restrictions have been made. The energies of positive parity levels are in agreement with a shell model calculation in the complete sd shell. (Auth.)

  9. Preliminary assessment of using tree-tissue analysis and passive-diffusion samplers to evaluate trichloroethene contamination of ground water at Site SS-34N, McChord Air Force Base, Washington, 2001

    Science.gov (United States)

    Cox, S.E.

    2002-01-01

    Two low-cost innovative sampling procedures for characterizing trichloroethene (TCE) contamination in ground water were evaluated for use at McChord Air Force Base (AFB) by the U.S. Geological Survey, in cooperation with the U.S. Air Force McChord Air Force Base Installation Restoration Program, in 2001. Previous attempts to characterize the source of ground-water contamination in the heterogeneous glacial outwash aquifer at McChord site SS-34N using soil-gas surveys, direct-push exploration, and more than a dozen ground-water monitoring wells have had limited success. The procedures assessed in this study involved analysis of tree-tissue samples to map underlying ground-water contamination and deploying passive-diffusion samplers to measure TCE concentrations in existing monitoring wells. These procedures have been used successfully at other U.S. Department of Defense sites and have resulted in cost avoidance and accelerated site characterization. Despite the presence of TCE in ground water at site SS-34N, TCE was not detected in any of the 20 trees sampled at the site during either early spring or late summer sampling. The reason the tree tissue procedure was not successful at the McChord AFB site SS-34N may have been due to an inability of tree roots to extract moisture from a water table 30 feet below the land surface, or that concentrations of TCE in ground water were not large enough to be detectable in the tree tissue at the sampling point. Passive-diffusion samplers were placed near the top, middle, and bottom of screened intervals in three monitoring wells and TCE was observed in all samplers. Concentrations of TCE from the passive-diffusion samplers were generally similar to concentrations found in samples collected in the same wells using conventional pumping methods. In contrast to conventional pumping methods, the collection of ground-water samples using the passive-diffusion samples did not generate waste purge water that would require hazardous-waste disposal. In addition, the results from the passive-diffusion samples may show that TCE concentrations are stratified across some screened intervals. The overall results of the limited test of passive-diffusion samplers at site SS-34N were similar to more detailed tests conducted at other contaminated sites across the country and indicate that further evaluation of the use of passive-diffusion samplers at McChord site SS-34N is warranted.

  10. Testing the cosmic censorship conjecture with point particles: The effect of radiation reaction and the self-force

    International Nuclear Information System (INIS)

    A classical thought-experiment to destroy black holes was envisaged by Wald in 1974: it consists of throwing particles with large angular momentum into an extremal black hole, checking whether their capture can overspin the black hole past the extremal limit and create a naked singularity. Wald showed that in the test-particle limit, particles that would be otherwise capable of producing naked singularities are simply scattered. Recently, Jacobson and Sotiriou showed that if one considers instead a black hole that is almost, but not exactly extremal, then in the absence of backreaction effects particle capture could indeed overspin the spacetime above the Kerr limit. Here we analyze backreaction effects and show that for some of the trajectories giving rise to naked singularities, radiative effects can be neglected. However, for these orbits the conservative self-force is important, and seems to have the right sign to prevent the formation of naked singularities.

  11. Light induced electron transfer reactions of metal complexes

    International Nuclear Information System (INIS)

    Properties of the excited states of tris(2,2'-bipyridine) and tris(1,10-phenanthroline) complexes of chromium(III), iron(II), ruthenium(II), osmium(II), rhodium(III), and iridium(III) are described. The electron transfer reactions of the ground and excited states are discussed and interpreted in terms of the driving force for the reaction and the distortions of the excited states relative to the corresponding ground states. General considerations relevant to the conversion of light into chemical energy are presented and progress in the use of polypyridine complexes to effect the light decomposition of water into hydrogen and oxygen is reviewed

  12. The CMS Experiment: on and under Ground Motions of Structures Due to the Magnetic Field Forces as Observed by the Link Alignment System

    International Nuclear Information System (INIS)

    This document describes results obtained from the Link Alignment System data recorded during the CMS Magnet Test (at SX5 on ground Hall) and the CRAFT08 and 09 periods data taking in the point P5 (UX5), 100 m underground. A brief description of the system is followed by the discussion of the detected relative displacements (from micrometres to centimetres) between detector elements and rotation of detector structures (from microradiants to milliradiants). Observed motions are studied as functions of the magnetic fi eld intensity. Comparisons between recorded data on and under ground are made. (Author) 23 refs.

  13. The CMS Experiment: on and under Ground Motions of Structures Due to the Magnetic Field Forces as Observed by the Link Alignment System

    Energy Technology Data Exchange (ETDEWEB)

    Alberdi, J.; Arce, J.; Barcala, J. M.; Calvo, E.; Ferrando, A.; Josa, M. I.; Molinero, A.; Navarrete, J.; Oller, J. C.; Yuste, C.; Brochero, J.; Calderon, A.; Fernandez, M. G.; Gomez, G.; Gonzalez-Sanchez, F. J.; Martinez-Ribero, C.; Matorras, F.; Rodrigo, T.; Rui-Arbol, P.; Scodellaro, L.; Sobron, M.; Vila, I.; Virto, A. L.; Fernandez, J.

    2010-05-01

    This document describes results obtained from the Link Alignment System data recorded during the CMS Magnet Test (at SX5 on ground Hall) and the CRAFT08 and 09 periods data taking in the point P5 (UX5), 100 m underground. A brief description of the system is followed by the discussion of the detected relative displacements (from micrometres to centimetres) between detector elements and rotation of detector structures (from microradiants to milliradiants). Observed motions are studied as functions of the magnetic fi eld intensity. Comparisons between recorded data on and under ground are made. (Author) 23 refs.

  14. Protein Folding as a Complex Reaction: A Two-Component Potential for the Driving Force of Folding and Its Variation with Folding Scenario

    Science.gov (United States)

    Chekmarev, Sergei F.

    2015-01-01

    The Helmholtz decomposition of the vector field of probability fluxes in a two-dimensional space of collective variables makes it possible to introduce a potential for the driving force of protein folding [Chekmarev, J. Chem. Phys. 139 (2013) 145103]. The potential has two components: one component (?) is responsible for the source and sink of the folding flow, which represent, respectively, the unfolded and native state of the protein, and the other (?) accounts for the flow vorticity inherently generated at the periphery of the flow field and provides the canalization of the flow between the source and sink. Both components obey Poisson’s equations with the corresponding source/sink terms. In the present paper, we consider how the shape of the potential changes depending on the scenario of protein folding. To mimic protein folding dynamics projected onto a two-dimensional space of collective variables, the two-dimensional Müller and Brown potential is employed. Three characteristic scenarios are considered: a single pathway from the unfolded to the native state without intermediates, two parallel pathways without intermediates, and a single pathway with an off-pathway intermediate. To determine the probability fluxes, the hydrodynamic description of the folding reaction is used, in which the first-passage folding is viewed as a steady flow of the representative points of the protein from the unfolded to the native state. We show that despite the possible complexity of the folding process, the ?-component is simple and universal in shape. The ?-component is more complex and reveals characteristic features of the process of folding. The present approach is potentially applicable to other complex reactions, for which the transition from the reactant to the product can be described in a space of two (collective) variables. PMID:25848943

  15. Three-body forces

    International Nuclear Information System (INIS)

    Three-body forces are defined and their properties discussed. Evidence for such forces in the trinucleon bound states and scattering reactions is reviewed. The binding energy defects of the trinucleon bound states, the 3He charge density, the Phillips line for doublet n-d scattering lengths, and three-nucleon breakup reactions are discussed, together with the possible influence of three-body forces on these observables

  16. Relationship between the forces acting on the horse's back and the movements of rider and horse while walking on a treadmill

    OpenAIRE

    von Peinen, K; Wiestner, T; Bogisch, S; Roepstorff, L.; Weeren, R; Weishaupt, M A

    2009-01-01

    Reasons for performing study: The exact relationship between the saddle pressure pattern during one stride cycle and the movements of horse and rider at the walk are poorly understood and have never been investigated in detail. Hypothesis: The movements of rider and horse account for the force distribution pattern under the saddle. Method: Vertical ground reaction forces (GRF), kinematics of horse and rider as well as saddle forces (FS) were measured synchronously in 7 high level dressage hor...

  17. Análisis cuantitativo de la evolución post-quirúrgica de la rotura de ligamento cruzado anterior mediante el uso de la plataforma de fuerza - Quantitative analysis of the evolution of post-surgical anterior cruciate ligament rupture using force platform

    Directory of Open Access Journals (Sweden)

    Vilar, JM

    2010-01-01

    Full Text Available ResumenEl analisis cinético mediante plataforma de fuerza es un método objetivo de cuantificar el apoyo de los miembros en los animales domésticos.SummarySummaryKinetic análisis by jeans of force platforms is an objetive method to measure weight - bearing or ground reaction force (GRF.

  18. Zero Horizontal Reaction Force Excavator

    Science.gov (United States)

    Mueller, Robert P. (Inventor); Nick, Andrew J. (Inventor); Schuler, Jason M. (Inventor); Smith, Jonathan D. (Inventor)

    2015-01-01

    An excavator includes a mobile chassis with a first bucket drum and a second bucket drum coupled thereto. The first bucket drum and second bucket drum are coupled to the chassis for positioning thereof on the surface at opposing ends of the chassis. Each first scoop on the first bucket drum is a mirror image of one second scoop on the second bucket drum when (i) the first bucket drum and second bucket drum are on the surface adjacent opposing ends of the chassis, and (ii) the first bucket drum is rotated in one direction and the second bucket drum is simultaneously rotated in an opposing direction.

  19. NRC Task Force report on review of the federal/state program for regulation of commercial low-level radioactive waste burial grounds

    International Nuclear Information System (INIS)

    The underlying issue explored in this report is that of Federal vs State regulation of commercial radioactive waste burial grounds. The need for research and development, a comprehensive set of standards and criteria, a national plan for low-level waste management, and perpetual care funding are closely related to the central issue and are also discussed. Five of the six commercial burial grounds are regulated by Agreement States; the sixth is regulated solely by the NRC (NRC also regulates Special Nuclear Material at the sites). The sites are operated commercially. The operators contribute to the perpetual care funds for the sites at varying rates. The States have commitments for the perpetual care of the decommissioned sites except for one site, located on Federally owned land. Three conclusions are reached. Federal control over the disposal of low-level waste should be increased by requiring joint Federal/State site approval, NRC licensing, Federal ownership of the land, and a Federally administered perpetual care program. The NRC should accelerate the development of its regulatory program for the disposal of low-level waste. The undisciplined proliferation of low-level burial sites must be avoided. NRC should evaluate alternative disposal methods, conduct necessary studies, and develop a comprehensive low-level waste regulatory program (i.e., accomplish the above recommendations) prior to the licensing of new disposal sites

  20. Análise da força articular resultante entre diferentes movimentos do ombro com e sem carga: estudo preliminar / Analysis of the joint reaction forces during different shoulder movements with and without external load: a preliminary study

    Scientific Electronic Library Online (English)

    Daniel Cury, Ribeiro; Jefferson Fagundes, Loss; Joelly Mahnic de, Toledo; Marcelo Peduzzi de, Castro; Fábia Milman, Krumholz; Felipe de Osório, Marques.

    Full Text Available Os modelos de segmentos rígidos são extremamente úteis para auxiliar a compreensão do tipo de sobrecarga que as articulações estão expostas. O objetivo deste trabalho foi analisar a força articular resultante e momento proximal durante atividades sem e com carga externa, em um estudo preliminar. Um [...] indivíduo realizou flexão, extensão, abdução de ombro e flexão de cotovelo (sem e com carga). Dados cinemáticos foram obtidos por videogrametria (freqüência de amostragem de 50 campos/s). Um modelo de segmentos rígidos foi utilizado para obtenção dos dados cinéticos. O modelo é regido pelas equações de movimento de Newton-Euler. Os resultados encontrados evidenciaram aumentos não proporcionais na força e momento resultante. A força resultante longitudinal foi a única que apresentou aumento proporcional frente à carga externa. As componentes da força de cisalhamento e momento proximal apresentaram aumentos aleatórios. O aumento da carga externa promoveu aumentos da força e momento proximal, porém não de forma proporcional. As componentes de força e momento resultante sofrem influência da carga externa de maneira independente. Isto evidencia a necessidade de um controle rígido sobre os exercícios prescritos para diferentes disfunções do membro superior. Abstract in english Link segment models are extremely useful for increasing the comprehension of joint overload. The aim of the present study was to analyze proximal joint reaction forces and moments during different movements performed with and without external load. One subject performed shoulder flexion, extension a [...] nd abduction, and elbow flexion movements (with and without external load) Kinematic data were obtained by videogrammetry (frequency sample 50 fields/s). One link segment model was used to obtain kinetic data. The model is governed by Newton/Euler movement equations. The results suggested a not proportional increasing of proximal joint reaction forces and moments. The proximal joint reaction force longitudinal component was the only one that increased proportionally to the external load. Proximal joint reaction force shearing components and proximal moments presented increasing values of different magnitudes. The use of external load promoted increased magnitudes of proximal joint reaction force and moment, although it was not proportional. Proximal joint reaction force and moment are influenced in different ways by the external load. This suggests the need of a strict control of the prescribed exercises for different shoulder dysfunctions.

  1. Ground Water

    Science.gov (United States)

    This United States Geological Survey (USGS) general interest publication presents a description of ground water in the U.S. This includes what ground water is, how it occurs, aquifers and wells, ground water quality and what affects it, and the state of U.S. ground water resources.

  2. Tracing ground-water evolution in a limestone aquifer using Sr isotopes: Effects of multiple sources of dissolved ions and mineral-solution reactions

    Science.gov (United States)

    Banner, Jay L.; Musgrove, Marylynn; Capo, R. C.

    1994-08-01

    Uplifted Pleistocene coral-reef terraces on Barbados, West Indies, constitute an aquifer that is built on low-permeability Tertiary pelagic rocks that overlie the Barbados accretionary prism. The downdip segments of the aquifer are composed of younger reef limestones that contain more aragonite and have higher 87Sr/86Sr and Sr/Ca ratios than the updip parts of the aquifer. Ground waters and host limestones display similar stratigraphic trends in 87Sr/86Sr and Sr/Ca. The ground waters have lower 87Sr/86Sr values, however, indicating that they acquire a significant fraction of their dissolved Sr through interaction with components of Tertiary rocks, which compose the underlying aquitard and parts of overlying soils. Geochemical modeling results indicate that ground-water evolution is controlled by (1) variations in the age and composition of the aquifer and aquitard rocks and (2) the relative roles of calcite dissolution, calcite recrystallization, and the transformation of aragonite to calcite. Sr isotopes can provide unique information for tracing ground-water evolution, which requires consideration of the multiple components and processes that make up even relatively simple limestone aquifer systems.

  3. Quenching of spin-M1 transition matrix elements and tensor force effect in the ground state in N=Z and even-even nuclei

    International Nuclear Information System (INIS)

    Quenching of spin-M1 transition matrix elements from even-even and N=Z nuclei across the sd shell region was studied by using high resolution (p, p') measurements at forward scattering angles including 0deg. The nuclear matrix elements corresponding to each excited state were deduced by using the differential cross section at 0deg estimated from unit cross section after sorting 1+ nuclear transition derived from the distinct form of angular distribution of differential scattering cross section measured. It was experimentally found from the comparison of the matrix elements calculated for the respective target nuclei with the shell-model calculation that the quenching was observed in the component of isovector, but not in the corresponding one of isoscalar. The difference between these isospins for M1 quenching is presumed to be resulted from the difference of tensor forces in the respective isospin transitions. (author)

  4. Ab initio study of {sup 2}H(d,{gamma}){sup 4}He, {sup 2}H(d,p){sup 3}H, and {sup 2}H(d,n){sup 4}He reactions and the tensor force

    Energy Technology Data Exchange (ETDEWEB)

    Arai, K.; Aoyama, S.; Suzuki, Y.; Descouvemont, P.; Baye, D. [Division of General Education, Nagaoka National College of Technology, 888 Nishikatakai, Nagaoka, Niigata, 940-8532 (Japan); Center for Academic Information Service, Niigata University, Niigata 950-2181 (Japan); Department of Physics, Niigata University, Niigata 950-2181, Japan and RIKEN Nishina Center, Wako 351-0198 (Japan); Physique Nucleaire Theorique et Physique Mathematique, C.P.229, Universite Libre de Bruxelles, B 1050 Brussels (Belgium); Physique Quantique, CP165/82, Universite Libre de Bruxelles, B-1050 Brussels (Belgium)

    2012-11-12

    The {sup 2}H(d,p){sup 3}H, {sup 2}H(d,n){sup 3}He, and {sup 2}H(d,{gamma}){sup 4}He reactions at low energies are studied with realistic nucleon-nucleon interactions in an ab initio approach. The obtained astrophysical S-factors are all in very good agreement with experiment. The most important channels for both transfer and radiative capture are all found to dominate thanks to the tensor force.

  5. Transition from wing to leg forces during landing in birds.

    Science.gov (United States)

    Provini, Pauline; Tobalske, Bret W; Crandell, Kristen E; Abourachid, Anick

    2014-08-01

    Transitions to and from the air are critical for aerial locomotion and likely shaped the evolution of flying animals. Research on take-off demonstrates that legs generate greater body accelerations compared with wings, and thereby contribute more to initial flight velocity. Here, we explored coordination between wings and legs in two species with different wingbeat styles, and quantified force production of these modules during the final phase of landing. We used the same birds that we had previously studied during take-off: zebra finch (Taeniopygia guttata, N=4) and diamond dove (Geopelia cuneata, N=3). We measured kinematics using high-speed video, aerodynamics using particle image velocimetry, and ground-reaction forces using a perch mounted on a force plate. In contrast with the first three wingbeats of take-off, the final four wingbeats during landing featured ~2 times greater force production. Thus, wings contribute proportionally more to changes in velocity during the last phase of landing compared with the initial phase of take-off. The two species touched down at the same velocity (~1 m s(-1)), but they exhibited significant differences in the timing of their final wingbeat relative to touchdown. The ratio of average wing force to peak leg force was greater in diamond doves than in zebra finches. Peak ground reaction forces during landing were ~50% of those during take-off, consistent with the birds being motivated to control landing. Likewise, estimations of mechanical energy flux for both species indicate that wings produce 3-10 times more mechanical work within the final wingbeats of flight compared with the kinetic energy of the body absorbed by legs during ground contact. PMID:24855670

  6. Ground-Level Ozone

    Science.gov (United States)

    Ground level or "bad" ozone is not emitted directly into the air, but is created by chemical reactions between oxides of nitrogen (NOx) and volatile ... the major sources of NOx and VOC. Breathing ozone can trigger a variety of health problems, particularly ...

  7. Unloading Reaction during Sudden Ankle Inversion in Healthy Adults

    OpenAIRE

    Jain, Tarang Kumar; Wauneka, Clayton; Liu, Wen

    2013-01-01

    The purpose of this research study was to determine the dynamics of early human response from sudden ankle inversion (30° tilt). Changes in vertical ground reaction forces (GRFs) following trapdoor release in a group of healthy subjects were compared to those from the similar experiments using a chair with two U shaped steel legs and matched weights of the human subjects. The experiments with the chair were further repeated with additional foam paddings at their bases to introduce visco-elas...

  8. Time-dependent quantum wave packet study of the Ar+H{sub 2}{sup +}{yields}ArH{sup +}+H reaction on a new ab initio potential energy surface for the ground electronic state (1{sup 2}A Prime )

    Energy Technology Data Exchange (ETDEWEB)

    Hu Mei; Liu Xinguo; Tan Ruishan; Li Hongzheng [College of Physics and Electronics, Shandong Normal University, Jinan 250014 (China); Xu Wenwu [Shanghai Institute of Applied Physics, Chinese Academy of Sciences, Shanghai 201800 (China)

    2013-05-07

    A new global potential energy surface for the ground electronic state (1{sup 2}A Prime ) of the Ar+H{sub 2}{sup +}{yields}ArH{sup +}+H reaction has been constructed by multi-reference configuration interaction method with Davidson correction and a basis set of aug-cc-pVQZ. Using 6080 ab initio single-point energies of all the regions for the dynamics, a many-body expansion function form has been used to fit these points. The quantum reactive scattering dynamics calculations taking into account the Coriolis coupling (CC) were carried out on the new potential energy surface over a range of collision energies (0.03-1.0 eV). The reaction probabilities and integral cross sections for the title reaction were calculated. The significance of including the CC quantum scattering calculation has been revealed by the comparison between the CC and the centrifugal sudden approximation calculation. The calculated cross section is in agreement with the experimental result at collision energy 1.0 eV.

  9. Time-dependent quantum wave packet study of the Ar+H2+?ArH(+)+H reaction on a new ab initio potential energy surface for the ground electronic state (1(2)A').

    Science.gov (United States)

    Hu, Mei; Xu, Wenwu; Liu, Xinguo; Tan, Ruishan; Li, Hongzheng

    2013-05-01

    A new global potential energy surface for the ground electronic state (1(2)A') of the Ar+H2(+)?ArH(+)+H reaction has been constructed by multi-reference configuration interaction method with Davidson correction and a basis set of aug-cc-pVQZ. Using 6080 ab initio single-point energies of all the regions for the dynamics, a many-body expansion function form has been used to fit these points. The quantum reactive scattering dynamics calculations taking into account the Coriolis coupling (CC) were carried out on the new potential energy surface over a range of collision energies (0.03-1.0 eV). The reaction probabilities and integral cross sections for the title reaction were calculated. The significance of including the CC quantum scattering calculation has been revealed by the comparison between the CC and the centrifugal sudden approximation calculation. The calculated cross section is in agreement with the experimental result at collision energy 1.0 eV. PMID:23656132

  10. Influence of velocity on horse and rider movement and resulting saddle forces at walk and trot

    OpenAIRE

    Bogisch, S; Geser-von Peinen, Katja; Wiestner, T; Roepstorff, L.; Weishaupt, M A

    2014-01-01

    To investigate the effect of increasing velocity within one gait on horse and rider movement and to describe the resulting changes in saddle forces, seven ridden dressage horses were examined on an instrumented treadmill. The speed ranged between 1.3-1.8 m/s at walk and 2.6-3.6 m/s at trot. Kinematics of the horse and rider, vertical ground reaction forces and saddle forces were measured simultaneously. Velocity dependency of each variable was assessed for the whole group with linear regressi...

  11. Crystalline beam ground state

    International Nuclear Information System (INIS)

    In order to employ Molecular Dynamics method, commonly used in condensed matter physics, we have derived the equations of motion for a beam of charged particles in the rotating rest frame of the reference particle. We include in the formalism that the particles are confined by the guiding and focusing magnetic fields, and that they are confined in a conducting vacuum pipe while interacting with each other via a Coulomb force. Numerical simulations has been performed to obtain the equilibrium structure. The effects of the shearing force, centrifugal force, and azimuthal variation of the focusing strength are investigated. It is found that a constant gradient storage ring can not give a crystalline beam, but that an alternating-gradient (AG) structure can. In such a machine the ground state is, except for one-dimensional (1-D) crystals, time-dependent. The ground state is a zero entropy state, despite the time-dependent, periodic variation of the focusing force. The nature of the ground state, similar to that found by Rahman and Schiffer, depends upon the density and the relative focusing strengths in the transverse directions. At low density, the crystal is 1-D. As the density increases, it transforms into various kinds of 2-D and 3-D crystals. If the energy of the beam is higher than the transition energy of the machine, the crystalline structure can not be formed for lack of radial focusing

  12. Crystalline beam ground state

    International Nuclear Information System (INIS)

    In order to employ molecular dynamics (MD) methods, commonly used in condensed matter physics, we have derived the equations of motion for a beam of charged particles in the rotating rest frame of the reference particle. We include in the formalism that the particles are confined by the guiding and focusing magnetic fields, and that they are confined in a conducting vacuum pipe while interacting with each other via a Coulomb force. Numerical simulations using MD methods has been performed to obtain the equilibrium crystalline beam structure. The effect of the shearing force, centrifugal force, and azimuthal variation of the focusing strength are investigated. It is found that a constant gradient storage ring can not give a crystalline beam, but that an alternating-gradient (AG) structure can. In such a machine the ground state is, except for one-dimensional (1-D) crystals, time dependent. The ground state is a zero entropy state, despite the time-dependent, periodic variation of the focusing force. The nature of the ground state, similar to that found by Schiffer et al. depends upon the density and the relative focusing strengths in the transverse directions. At low density, the crystal is 1-D. As the density increases, it transforms into various kinds of 2-D and 3-D crystals. If the energy of the beam is higher than the transition energy of the machine, the crystalline structure can not be formed for lack of radial focusing

  13. Comparison of natural and artificial forcing to study the dynamic behaviour of bell towers in low wind context by means of ground-based radar interferometry: the case of the Leaning Tower in Pisa

    Science.gov (United States)

    Marchisio, Mario; Piroddi, Luca; Ranieri, Gaetano; Calcina, Sergio V.; Farina, Paolo

    2014-10-01

    The study of Cultural Heritage assets needs the application of non-destructive and non-invasive monitoring techniques. In particular, monuments and historical buildings which are open to the visitors and/or subject to important stress must be studied for their dynamic response. In the last 10?years the new ground-based radar interferometry technology has been developed allowing to monitor displacements from a point of sight far from the studied targets. It virtually provides a continuous mapping of displacements of the observed structures up to 10?µm with a range resolution of 0.75?m. In this paper, the application of ground-based interferometry on one very important historical building, the Leaning Tower of Pisa in Italy, is reported. The analysis of these kind of structures is important to catch their dynamic response to natural actions in general, and also to assess the effects due to pedestrian and users, and consequently to define functional capabilities and levels of acceptable dynamic stress. The studied structure was subject to artificial loading by synchronous movement of about 20 people. Artificial forcing led the structure to a resonance condition with the same frequency of the one due to the natural noise excitation, which was separately measured, and with an oscillation amplitude more than thirty times greater than the natural one (in conditions of weak wind). During the passive stages of the survey the recorded structural vibrations were very closed to the instrumental sensitivity, making difficult to distinguish vibration amplitudes amplifications of various segments at various heights. Through the spectral analysis of the acquired data it was possible to estimate the vibration frequencies of the first modal shapes of the structure along two orthogonal directions. The power spectra of the passive survey data have the same maximum frequency of the active but contain more noise at low frequency.

  14. A force platform for large human displacements.

    Science.gov (United States)

    Desjardins, P; Gagnon, M

    2001-03-01

    This paper provides details of a force platform assembly suitable for measuring the magnitude, position and direction of ground reaction forces for manual handling tasks involving several footsteps in any horizontal direction. An approach to increase the natural frequency with the use of a vibration absorber is used; this frequency was found to be 41+/-2 Hz. The results show a maximum error of 22 N (2% of the full scale output) when a person performs repetitive movements from a squat position to a full extension and back to the squat position. Static tests show the maximal errors to be, vertically, 1.5% of the full scale output (1818+/-33 N), and horizontally, 4.9% of the full scale output (1177+/-6 N). PMID:11413067

  15. Design and Operation of a Borehole Straddle Packer for Ground-Water Sampling and Hydraulic Testing of Discrete Intervals at U.S. Air Force Plant 6, Marietta, Georgia

    Science.gov (United States)

    Holloway, Owen G.; Waddell, Jonathan P.

    2008-01-01

    A borehole straddle packer was developed and tested by the U.S. Geological Survey to characterize the vertical distribution of contaminants, head, and hydraulic properties in open-borehole wells as part of an ongoing investigation of ground-water contamination at U.S. Air Force Plant 6 (AFP6) in Marietta, Georgia. To better understand contaminant fate and transport in a crystalline bedrock setting and to support remedial activities at AFP6, numerous wells have been constructed that include long open-hole intervals in the crystalline bedrock. These wells can include several discontinuities that produce water, which may contain contaminants. Because of the complexity of ground-water flow and contaminant movement in the crystalline bedrock, it is important to characterize the hydraulic and water-quality characteristics of discrete intervals in these wells. The straddle packer facilitates ground-water sampling and hydraulic testing of discrete intervals, and delivery of fluids including tracer suites and remedial agents into these discontinuities. The straddle packer consists of two inflatable packers, a dual-pump system, a pressure-sensing system, and an aqueous injection system. Tests were conducted to assess the accuracy of the pressure-sensing systems, and water samples were collected for analysis of volatile organic compound (VOCs) concentrations. Pressure-transducer readings matched computed water-column height, with a coefficient of determination of greater than 0.99. The straddle packer incorporates both an air-driven piston pump and a variable-frequency, electronic, submersible pump. Only slight differences were observed between VOC concentrations in samples collected using the two different types of sampling pumps during two sampling events in July and August 2005. A test conducted to assess the effect of stagnation on VOC concentrations in water trapped in the system's pump-tubing reel showed that concentrations were not affected. A comparison was conducted to assess differences between three water-sampling methods - collecting samples from the well by pumping a packer-isolated zone using a submersible pump, by using a grab sampler, and by using a passive diffusion sampler. Concentrations of tetrachloroethylene, trichloroethylene and 1,2-dichloropropane were greatest for samples collected using the submersible pump in the packed-isolated interval, suggesting that the straddle packer yielded the least dilute sample.

  16. Evidence for the ground-state resonance of 26O

    CERN Document Server

    Lunderberg, E; Kohley, Z; Attanayake, H; Baumann, T; Bazin, D; Christian, G; Divaratne, D; Grimes, S M; Haagsma, A; Finck, J E; Frank, N; Luther, B; Mosby, S; Nagy, T; Peaslee, G F; Schiller, A; Snyder, J; Spyrou, A; Strongman, M J; Thoennessen, M

    2012-01-01

    Evidence for the ground state of the neutron-unbound nucleus 26O was observed for the first time in the single proton-knockout reaction from a 82 MeV/u 27F beam. Neutrons were measured in coincidence with 24O fragments. 26O was determined to be unbound by 150+50-150 keV from the observation of low-energy neutrons. This result agrees with recent shell model calculations based on microscopic two- and three-nucleon forces.

  17. Exact integral constraint requiring only the ground-state electron density as input on the exchange-correlation force - partial differential(V)(xc)(r)/partial differential(r) for spherical atoms.

    Science.gov (United States)

    March, N H; Nagy, A

    2008-11-21

    Following some studies of integral(n)(r)inverted DeltaV(r)dr by earlier workers for the density functional theory (DFT) one-body potential V(r) generating the exact ground-state density, we consider here the special case of spherical atoms. The starting point is the differential virial theorem, which is used, as well as the Hiller-Sucher-Feinberg [Phys. Rev. A 18, 2399 (1978)] identity to show that the scalar quantity paralleling the above vector integral, namely, integral(n)(r) partial differential(V)(r)/partial differential(r)dr, is determined solely by the electron density n(0) at the nucleus for the s-like atoms He and Be. The force - partial differential(V)/ partial differential(r) is then related to the derivative of the exchange-correlation potential V(xc)(r) by terms involving only the external potential in addition to n(r). The resulting integral constraint should allow some test of the quality of currently used forms of V(xc)(r). The article concludes with results from the differential virial theorem and the Hiller-Sucher-Feinberg identity for the exact many-electron theory of spherical atoms, as well as for the DFT for atoms such as Ne with a closed p shell. PMID:19026052

  18. An experimental guided-ion-beam and ab initio study of the ion-molecule gas-phase reactions between Li+ ions and iso-C3H7Cl in their ground electronic state

    International Nuclear Information System (INIS)

    Reactive collisions between Li+ ions and i-C3H7Cl molecules have been studied in the 0.20-12.00 eV center-of-mass energy range using an octopole radio frequency guided-ion beam apparatus recently developed in our laboratory. At low collision energies, dehydrohalogenation reactions giving rise to Li(C3H6)+ and Li(HCl)+ are the main reaction channels, while at higher ones C3H7+ and C2H3+ become dominant, all their reactive cross sections having been measured as a function of the collision energy. To obtain information about the potential energy surfaces (PESs) on which the reactive processes take place, ab initio calculations at the MP2 level have been performed. For dehydrohalogenations, the reactive ground singlet PES shows ion-molecule adduct formation in both the reactant and product sides of the surface. Following the minimum energy path connecting both minima, an unstable intermediate and the corresponding barriers, both lying below the reactant's energy, have been characterized. The entrance channel ion-molecule adduct is also involved in the formation of C3H7+, which then generates C2H3+ via an CH4 unimolecular elimination. A qualitative interpretation of the experimental results based on ab initio calculations is also included.ations is also included.

  19. A new potential energy surface for the ground electronic state of the LiH2 system, and dynamics studies on the H((2)S) + LiH(X(1)?(+)) ? Li((2)S) + H2(X(1)?g(+)) reaction.

    Science.gov (United States)

    Yuan, Jiuchuang; He, Di; Chen, Maodu

    2015-05-01

    A new global potential energy surface (PES) is obtained for the ground electronic state of the LiH2 system based on high-level energies. The energy points are calculated at the multireference configuration interaction level with aug-cc-pVXZ (X = Q, 5) basis sets, and these energies are extrapolated to the complete basis set limit. The neural network method and hierarchical construction scheme are applied in the fitting process and the root mean square error of the fitting result is very small (0.004 eV). The dissociation energies and equilibrium distances for LiH(X(1)?(+)) and H2(X(1)?g(+)) obtained from the new PES are in good agreement with the experimental data. On the new PES, time-dependent wave packet studies for the H((2)S) + LiH(X(1)?(+)) ? Li((2)S) + H2(X(1)?g(+)) reaction have been carried out. In this reaction, no threshold is found due to the absence of an energy barrier on the minimum energy path. The calculated integral cross sections are high at low collision energy and will decrease with the increase of the collision energy. The product molecule H2 tends to be forward scattering due to direct reactive collisions, which becomes more evident at higher collision energies. PMID:25870863

  20. In vivo lumbo-sacral forces and moments during constant speed running at different stride lengths.

    Science.gov (United States)

    Seay, Joseph; Selbie, W Scott; Hamill, Joseph

    2008-12-01

    The aim of this study was to introduce a Newton-Euler inverse dynamics model that included reaction force and moment estimation at the lumbo-sacral (L5-S1) and thoraco-lumbar (T12-L1) joints. Data were collected while participants ran over ground at 3.8 m x s(-1) at three different stride lengths: preferred stride length, 20% greater than preferred, and 20% less than preferred. Inputs to the model were ground reaction forces, bilateral lower extremity and pelvis kinematics and inertial parameters, kinematics of the lumbar spine and thorax and inertial parameters of the lumbar segment. Repeated measures ANOVA were performed on the lower extremity sagittal kinematics and kinetics, including L5-S1 and T12-L1 three-dimensional joint angles, reaction forces and moments at touchdown and peak values during impact phase across the three stride conditions. Results indicated that L5-S1 and T12-L1 vertical reaction forces at touchdown and during the impact portion of the support phase increased significantly as stride length increased (P < 0.001), as did peak sagittal L5-S1 moments during impact (P = 0.018). Additionally, the transverse T12-L1 joint moment increased as running speed increased (P = 0.006). We concluded from our findings that our model was sensitive to our perturbations in healthy runners, and may prove useful in future mechanistic studies of L5-S1 mechanics. PMID:18937134

  1. Half-Lives of ground states in Pm and Eu nuclei following the 154,152Sm (p,x) reactions at 25 MeV

    Science.gov (United States)

    Watwood, N. J.; Beausang, C. W.; Humby, P.; Simon, A.; Gell, K.

    2014-09-01

    The primary experiment was designed to study low/medium spin states in Sm nuclei following the 154,152Sm (p,x) reactions where x = d or t. During the experiment the Sm target was irradiated by a 25 MeV proton beam, provided by the K150 Cyclotron at Texas A&M University, with an average beam current of ~1 nA for about one week. Following the experiment, residual radioactivity in the target was measured in the Environmental Radioactivity Laboratory at the University of Richmond using a 25% efficiency coaxial Ge detector enclosed in a 6-inch thick Pb shield. The gamma ray spectra were internally calibrated using a 152Eu source and the energies of known gamma-rays from the target decays and from long lived environmental radioactivity. The decays of three long lived (~1 month or more) mass A ~ 150 nuclei were identified (148Sm, 148Eu, and 147Eu), and half lives for their beta-decay were (re)measured. Work is still in progress and preliminary results will be presented at the APS conference.

  2. Methods for Addressing Uncertainty and Variability to Characterize Potential Health Risk from Trichloroethylene-Contaminated Ground Water at Beale Air Force Base in California:Integration of Uncertainty and Variability in Pharmacokinetics and Dose-Response

    Energy Technology Data Exchange (ETDEWEB)

    Bogen, K T

    2001-05-24

    Traditional estimates of health risk are typically inflated, particularly if cancer is the dominant endpoint and there is fundamental uncertainty as to mechanism(s) of action. Risk is more realistically characterized if it accounts for joint uncertainty and interindividual variability within a systematic probabilistic framework to integrate the joint effects on risk of distributed parameters of all (linear as well as nonlinear) risk-extrapolation models involved. Such a framework was used to characterize risks to potential future residents posed by trichloroethylene (TCE) in ground water at an inactive landfill site on Beale Air Force Base in California. Variability and uncertainty were addressed in exposure-route-specific estimates of applied dose, in pharmacokinetically based estimates of route-specific metabolized fractions of absorbed TCE, and in corresponding biologically effective doses estimated under a genotoxic/linear (MA{sub G}) vs. a cytotoxic/nonlinear (MA{sub c}) mechanistic assumption for TCE-induced cancer. Increased risk conditional on effective dose was estimated under MA{sub G} based on seven rodent-bioassay data sets, and under MA{sub c} based on mouse hepatotoxicity data. Mean and upper-bound estimates of combined risk calculated by the unified approach were <10{sup -6} and 10{sup -4}, respectively, while corresponding estimates based on traditional deterministic methods were >10{sup -5} and 10{sup -4}, respectively. It was estimated that no TCE-related harm is likely to occur due to any plausible residential exposure scenario involving the site. The systematic probabilistic framework illustrated is particularly suited to characterizing risks that involve uncertain and/or diverse mechanisms of action.

  3. Motion synthesis and force distribution analysis for a biped robot.

    Science.gov (United States)

    Trojnacki, Maciej T; Zieli?ska, Teresa

    2011-01-01

    In this paper, the method of generating biped robot motion using recorded human gait is presented. The recorded data were modified taking into account the velocity available for robot drives. Data includes only selected joint angles, therefore the missing values were obtained considering the dynamic postural stability of the robot, which means obtaining an adequate motion trajectory of the so-called Zero Moment Point (ZMT). Also, the method of determining the ground reaction forces' distribution during the biped robot's dynamic stable walk is described. The method was developed by the authors. Following the description of equations characterizing the dynamics of robot's motion, the values of the components of ground reaction forces were symbolically determined as well as the coordinates of the points of robot's feet contact with the ground. The theoretical considerations have been supported by computer simulation and animation of the robot's motion. This was done using Matlab/Simulink package and Simulink 3D Animation Toolbox, and it has proved the proposed method. PMID:21761810

  4. Racial Composition of the Volunteer Armed Forces

    Science.gov (United States)

    Janowitz, Morris; Moskos, Charles C., Jr.

    1975-01-01

    Analyzes Department of Defense statistics, noting that to examine the question of racial composition in the all-volunteer force is to focus on the enlisted personnel of the ground combat units; and asserting that, in the long run, the end of black over concentration in the ground combat forces necessitates effective racial equality and dignity in…

  5. The human foot and heel-sole-toe walking strategy: a mechanism enabling an inverted pendular gait with low isometric muscle force?

    Science.gov (United States)

    Usherwood, J R; Channon, A J; Myatt, J P; Rankin, J W; Hubel, T Y

    2012-10-01

    Mechanically, the most economical gait for slow bipedal locomotion requires walking as an 'inverted pendulum', with: I, an impulsive, energy-dissipating leg compression at the beginning of stance; II, a stiff-limbed vault; and III, an impulsive, powering push-off at the end of stance. The characteristic 'M'-shaped vertical ground reaction forces of walking in humans reflect this impulse-vault-impulse strategy. Humans achieve this gait by dissipating energy during the heel-to-sole transition in early stance, approximately stiff-limbed, flat-footed vaulting over midstance and ankle plantarflexion (powering the toes down) in late stance. Here, we show that the 'M'-shaped walking ground reaction force profile does not require the plantigrade human foot or heel-sole-toe stance; it is maintained in tip-toe and high-heel walking as well as in ostriches. However, the unusual, stiff, human foot structure--with ground-contacting heel behind ankle and toes in front--enables both mechanically economical inverted pendular walking and physiologically economical muscle loading, by producing extreme changes in mechanical advantage between muscles and ground reaction forces. With a human foot, and heel-sole-toe strategy during stance, the shin muscles that dissipate energy, or calf muscles that power the push-off, need not be loaded at all--largely avoiding the 'cost of muscle force'--during the passive vaulting phase. PMID:22572024

  6. Design Optimization of Ground Clearance of Domestic Cars

    OpenAIRE

    Debojyoti Mitra

    2010-01-01

    Drag and lift forces plays a vital role in the performance and stability of vehicles. Less drag means less fuel consumption and hence less vehicular pollution. Also, lower lift force means higher chance of adhesion of the car body with the ground causing less overturning of the vehicle, which improves the vehicle performance. Both drag and lift forces can be manipulated by varying the ground clearance of the cars. The present study concentrates on studying the effect of ground clearance on th...

  7. Ground water

    International Nuclear Information System (INIS)

    There is growing evidence that the Nation's ground water is contaminated by a variety of sources. These include unprotected industrial, municipal, and radioactive disposal sites, petroleum exploration and mining activities, agricultural operations such as insecticide spraying, high de-icing salts and others. As of March 1980, more than 8000 chemical tests have been performed on well water, with chlorinated organic solvents found most frequently. Because 100 million Americans may be threatened by unfit drinking water, EPA has developed a new ground water strategy. It will enlist the help of State and local governments who already have programs under way and it will involve broad public debate and participation

  8. Some applications of the virial theorem to molecular force fields: the zero virial reaction coordinate and diatomic potentials from the normalized kinetic field functions

    International Nuclear Information System (INIS)

    For a fixed-angle potential energy surface (PES), W(Q), following the zero virial path (ZVP), on which ?/sub ?//sup N/Q/sub ?/ . del /sub ?/W(Q) = 0, provides an efficient way for locating the transition state and generating a good approximation to the minimum-energy reaction path; vector Q = (Q1, ..., Q/sub N/ stands for nuclear coordinates. An algorithm which employs the ZVP following is proposed for exploring PESs when starting from the reactant (or product) region. It seems that this approach allows one to avoid some discontinuities in the reaction coordinate, which often result from the bottom-following procedures. The implications of the integral forms of the virial theorem are examined and a new way of constructing potential energy functions W(R) for diatomic molecules is proposed. It starts with the normalization of the kinetic component T(R) of the potential: integral0/sup infinity/[T(R) - T(infinity)]dR = Z/sub A/Z/sub B/, where Z/sub A/ and Z/sub B/ are the nuclear charges and R is the internuclear distance. The modified potentials are derived for four different analytical representations of T(R), T/sub X(R)(X = M, R, RM, and HH) by the Morse, Rydberg, Rosen--Morse, and Hulbert--Hirschfelder functions, respectively. The three-parameter modified potentials (X = M, R, and RM) are tested against known spectroscopic data for H2+ and H2.The modified potentials require one less experimental constant to fie one less experimental constant to fit the potential parameters than do their original analogs. It follows that the Morse and Rydberg functions constitute satisfactory representations of the kinetic component T(R), and that enforcing its normalization improves predictions of spectroscopic constants and relations between them. 46 references

  9. 78 FR 20852 - Safety Zones; Marine Week Air Ground Demonstration, Lake Washington; Seattle, WA

    Science.gov (United States)

    2013-04-08

    ...the Corps' Marine Air Ground Task Force and expeditionary...Proposed Rule The Marine Air Ground Task Force Demonstration...will include low flying aircraft, amphibious vehicles...is for the Marine Air Ground Task Force Demonstration...assessment of potential costs and benefits...

  10. Fractal Reaction Kinetics

    Science.gov (United States)

    Kopelman, Raoul

    1988-09-01

    Classical reaction kinetics has been found to be unsatisfactory when the reactants are spatially constrained on the microscopic level by either walls, phase boundaries, or force fields. Recently discovered theories of heterogeneous reaction kinetics have dramatic consequences, such as fractal orders for elementary reactions, self-ordering and self-unmixing of reactants, and rate coefficients with temporal ``memories.'' The new theories were needed to explain the results of experiments and supercomputer simulations of reactions that were confined to low dimensions or fractal dimensions or both. Among the practical examples of ``fractal-like kinetics'' are chemical reactions in pores of membranes, excitation trapping in molecular aggregates, exciton fusion in composite materials, and charge recombination in colloids and clouds. Diffusion-controlled reactions with geometrical constraints, as found in heterogeneous kinetics, may be described by reactions on fractal domains. The hallmarks of ``fractal-like'' reactions are anomalous reaction orders and time-dependent reaction rate ``constants.'' These anomalies stem from the nonrandomness of the reactant distributions in low dimensions. For homo-bimolecular reactions (A + A --> Pr) the distribution is partially ordered, for example, quasi-periodic. However, for hetero-bimolecular reactions (A + B --> Pr) the reactants segregate. Theory, simulations, and experiments are interrelated through the formalism of fractal reaction kinetics (42).

  11. Coaxial Atomic Force Microscope Tweezers

    CERN Document Server

    Brown, K A; Westervelt, R M

    2010-01-01

    We demonstrate coaxial atomic force microscope (AFM) tweezers that can trap and place small objects using dielectrophoresis (DEP). An attractive force is generated at the tip of a coaxial AFM probe by applying a radio frequency voltage between the center conductor and a grounded shield; the origin of the force is found to be DEP by measuring the pull-off force vs. applied voltage. We show that the coaxial AFM tweezers (CAT) can perform three dimensional assembly by picking up a specified silica microsphere, imaging with the microsphere at the end of the tip, and placing it at a target destination.

  12. Effect of increased pushoff during gait on hip joint forces.

    Science.gov (United States)

    Lewis, Cara L; Garibay, Erin J

    2015-01-01

    Anterior acetabular labral tears and anterior hip pain may result from high anteriorly directed forces from the femur on the acetabulum. While providing more pushoff is known to decrease sagittal plane hip moments, it is unknown if this gait modification also decreases hip joint forces. The purpose of this study was to determine if increasing pushoff decreases hip joint forces. Nine healthy subjects walked on an instrumented force treadmill at 1.25 m/s under two walking conditions. For the natural condition, subjects were instructed to walk as they normally would. For the increased pushoff condition, subjects were instructed to "push more with your foot when you walk". We collected motion data of markers placed on the subjects' trunk and lower extremities to capture trunk and leg kinematics and ground reaction force data to determine joint moments. Data were processed in Visual3D to produce the inverse kinematics and model scaling files. In OpenSim, the generic gait model (Gait2392) was scaled to the subject, and hip joint forces were calculated for the femur on the acetabulum after computing the muscle activations necessary to reproduce the experimental data. The instruction to "push more with your foot when you walk" reduced the maximum hip flexion and extension moment compared to the natural condition. The average reduction in the hip joint forces were 12.5%, 3.2% and 9.6% in the anterior, superior and medial directions respectively and 2.3% for the net resultant force. Increasing pushoff may be an effective gait modification for people with anterior hip pain. PMID:25468661

  13. Modelo 3D para quantificação das forças articulares e momentos proximais resultantes para o membro superior / 3D model for analysis of resultant proximal reaction forces and moments for the upper limb

    Scientific Electronic Library Online (English)

    Daniel Cury, Ribeiro; Jefferson Fagundes, Loss.

    Full Text Available Objetivos: Este estudo teve como objetivo implementar um modelo biomecânico, de segmentos articulados, associado à dinâmica inversa que permita a análise em três dimensões das forças de reação proximais e momentos proximais resultantes para diferentes gestos do membro superior. Método: Os gestos ava [...] liados foram: flexão, extensão e abdução de ombro e flexão de cotovelo, os quais foram realizados por um indivíduo do sexo masculino. O modelo implementado é composto por cinco segmentos rígidos (mão, antebraço, braço, escápula e tronco) conectados. As equações de movimento de Newton-Euler foram utilizadas para quantificação das forças e momentos proximais resultantes. Para registro cinemático foram utilizadas cinco câmeras digitais, com freqüência de amostragem de 50 campos/seg. A precisão estimada do sistema de videogrametria foi, em média, de 1,7 mm. Foi monitorada a atividade eletromiográfica dos músculos deltóide (anterior, médio e posterior), bíceps braquial, tríceps braquial e peitoral maior. O modelo foi avaliado através da comparação qualitativa dos resultados de momento proximal resultante, com a atividade eletromiográfica. Resultados: Os resultados sugerem que o modelo apresenta resultados coerentes. O sinal eletromiográfico e o momento proximal apresentam sincronismo temporal. Conclusão: O modelo foi capaz de estimar as forças de reacção e momentos proximais resultantes nos diferentes gestos. Abstract in english Objectives: The aim of this study was to implement a biomechanical model, with linked segments associated with inverse dynamics, to analyze proximal net forces and moments during different upper limbs’ activities. Methods: one male subject performed flexion, extension and abduction of the shoulder a [...] nd flexion of the elbow. The model is composed of five connected rigid segments (hand, forearm, arm, scapula and trunk). The Newton-Euler motion equations were used to quantify proximal net reaction forces and moments. For kinematics recording, five cameras with a frequency sample of 50 fps were used. Videogrammetry accuracy was, on average, 1,7mm. The following muscles had their activities monitored: deltoid (anterior, medial, posterior), biceps brachialis, triceps brachialis, pectoralis major. The model was evaluated by qualitative comparison of proximal net moments with electromyographic signal of agonist muscles. Results: The results showed a temporal synchronism between the proximal net moments and agonist EMG activity. Conclusions: The model was able to estimate proximal net forces and moments during different upper limbs’ activities.

  14. Nuclear reactions

    International Nuclear Information System (INIS)

    This chapter of the textbook overviews nuclear reactions discussing the reaction mechanisms and the types of nuclear reactions, e.g. those induced by neutrons, by protons, by alpha particles and gamma photons, and finally, deuteron and thermonuclear reactions

  15. Correlations of quasi particles in the deformed nuclei ground states

    International Nuclear Information System (INIS)

    The effect of ground state correlation on the properties of the one-phonon states in deformed nuclei is considered. The isoscalar and isovector multipole forces are taken into account. The calculations with fixed energies of first one-phonon states are shown that the ground state correlation leads to small increase of collectivity of these states. The isovector force inclusion decreases the role of correlations. On the whole, the effect of ground state correlations is small even for strongly collective states

  16. EXTENDED HÜCKEL ORBITAL FORCES

    Directory of Open Access Journals (Sweden)

    Federico Eisner

    2003-12-01

    Full Text Available The forces acting on individual atoms in a molecule, arising from the distorting effect on the molecular framework of the electrons in the different populated molecular orbitals, are calculated within a simple Extended Hückel formalism. The method, which is strongly dependent on the properties of overlap integrals, is applied to the study of several processes and reactions of chemical interest, such as conformational stability of molecules, torsional stability for rotations around a single bond of some simple molecules and the connection between the forces acting upon atoms and the rules derived from conservation of orbital symmetry in concerted reaction. The results show good agreement with the experimental evidence and the known symmetry rules

  17. Level locomotion in wood ants: evidence for grounded running.

    Science.gov (United States)

    Reinhardt, Lars; Blickhan, Reinhard

    2014-07-01

    In order to better understand the strategies of locomotion in small insects, we have studied continuous level locomotion of the wood ant species Formica polyctena. We determined the three-dimensional centre of mass kinematics during the gait cycle and recorded the ground reaction forces of single legs utilising a self-developed test site. Our findings show that the animals used the same gait dynamics across a wide speed range without dissolving the tripodal stride pattern. To achieve higher velocities, the ants proportionally increased stride length and stepping frequency. The centre of mass energetics indicated a bouncing gait, in which horizontal kinetic and gravitational potential energy fluctuated in close phase. We determined a high degree of compliance especially in the front legs, as the effective leg length was nearly halved during the contact phase. This leads to only small vertical oscillations of the body, which are important in maintaining ground contact. Bouncing gaits without aerial phases seem to be a common strategy in small runners and can be sufficiently described by the bipedal spring-loaded inverted pendulum model. Thus, with our results, we provide evidence that wood ants perform 'grounded running'. PMID:24744414

  18. Earth Force

    Science.gov (United States)

    "Earth Force engages young people as active citizens who improve the environment and their communities now and in the future." Educators can learn about Earth Force's three programs: Community Action and Problem solving (CAPS), the Global Rivers Environmental Education Network (GREEN), and Earth Force After School. Users can discover students' many accomplishments such as creating reusable fabric grocery bags, recycling cell phones and ink cartridges to earn money, and cleaning up litter. The Tools for Teachers section offers evaluation results, a quality rubric, and a description of the six-step Earth Force community action and problem-solving process.

  19. Investigation of ground state features of some medical radionuclides

    Energy Technology Data Exchange (ETDEWEB)

    Tel, Eyyup; Kara, Ayhan [Osmaniye Korkut Ata Univ. (Turkey). Dept. of Physics; Aydin, Abdullah [Kirikkale Univ. (Turkey). Dept. of Physics; Kaplan, Abdullah [Sueleyman Demirel Univ., Isparta (Turkey). Dept. of Physics

    2012-03-15

    In this study, ground state properties for some medical radionuclides used widely in medical applications have been investigated using Skyrme-Hartree-Fock (SHF) method. We calculated the proton, neutron and charge density RMS (root-mean-square) radii of some medical radionuclides such, as {sup 42}K {sup 45}Ca, {sup 81}Kr, {sup 81}Rb, {sup 82}Rb, {sup 85}Sr, {sup 110}In, {sup 111}In, {sup 123}Cs, {sup 201}Tl and {sup 201}Pb using the SHF calculations with the Skyrme force parameters. The calculated results are compared with the available experimental values for charge density RMS radii. The proton, neutron, charge and mass density distributions for all nuclei used in this study have also been calculated. The calculated conclusions can be used in estimating nuclear properties of the medical nuclei and for the calculations of pre-equilibrium reactions cross section data for the production of new medical radioisotopes. (orig.)

  20. Investigation of ground state features of some medical radionuclides

    International Nuclear Information System (INIS)

    In this study, ground state properties for some medical radionuclides used widely in medical applications have been investigated using Skyrme-Hartree-Fock (SHF) method. We calculated the proton, neutron and charge density RMS (root-mean-square) radii of some medical radionuclides such, as 42K 45Ca, 81Kr, 81Rb, 82Rb, 85Sr, 110In, 111In, 123Cs, 201Tl and 201Pb using the SHF calculations with the Skyrme force parameters. The calculated results are compared with the available experimental values for charge density RMS radii. The proton, neutron, charge and mass density distributions for all nuclei used in this study have also been calculated. The calculated conclusions can be used in estimating nuclear properties of the medical nuclei and for the calculations of pre-equilibrium reactions cross section data for the production of new medical radioisotopes. (orig.)

  1. The amazing normal forces

    CERN Document Server

    Petrache, Horia I

    2012-01-01

    This manuscript is written for students in introductory physics classes to address some of the common difficulties and misconceptions of the normal force, especially the relationship between normal and friction forces. Accordingly, it is intentionally informal and conversational in tone to teach students how to build an intuition to complement mathematical formalism. This is accomplished by beginning with common and everyday experience and then guiding students toward two realizations: (i) That real objects are deformable even when deformations are not easily visible, and (ii) that the relation between friction and normal forces follows from the action-reaction principle. The traditional formulae under static and kinetic conditions are then analyzed to show that peculiarity of the normal-friction relationship follows readily from observations and knowledge of physics principles.

  2. Different forces

    CERN Multimedia

    1982-01-01

    The different forces, together with a pictorial analogy of how the exchange of particles works. The table lists the relative strength of the couplings, the quanta associated with the force fields and the bodies or phenomena in which they have a dominant role.

  3. Kinetic and dynamic studies of the Cl(2Pu) + H2O(tilde X1A1) ? HCl(tilde X1?+) + OH(tilde X2?) reaction on an ab initio based full-dimensional global potential energy surface of the ground electronic state of ClH2O

    Science.gov (United States)

    Li, Jun; Dawes, Richard; Guo, Hua

    2013-08-01

    Extensive high-level ab initio calculations were performed on the ground electronic state of ClH2O. The barrier region for the title reaction was found to have significant multi-reference character, thus favoring the multi-reference configuration interaction (MRCI) method over single-reference methods such as coupled-cluster. A full-dimensional global potential energy surface was developed by fitting about 25 000 MRCI points using the permutation invariant polynomial method. The reaction path features a "late" barrier flanked by deep pre- and post-barrier wells. Calculated rate constants for the forward reaction are in reasonable agreement with experiment, suggesting a good representation of the forward barrier. The dynamics of the forward reaction was also investigated using a quasi-classical trajectory method at energies just above the barrier. While the OH bond is found to be a spectator, the HCl product has significant rotational excitation. The reaction proceeds via both direct rebound and stripping mechanisms, leading to backward and sideways scattering.

  4. Kinetic and dynamic studies of the Cl(2Pu) + H2O(X?1A1) ? HCl(X?1?+) + OH(X?2?) reaction on an ab initio based full-dimensional global potential energy surface of the ground electronic state of ClH2O.

    Science.gov (United States)

    Li, Jun; Dawes, Richard; Guo, Hua

    2013-08-21

    Extensive high-level ab initio calculations were performed on the ground electronic state of ClH2O. The barrier region for the title reaction was found to have significant multi-reference character, thus favoring the multi-reference configuration interaction (MRCI) method over single-reference methods such as coupled-cluster. A full-dimensional global potential energy surface was developed by fitting about 25?000 MRCI points using the permutation invariant polynomial method. The reaction path features a "late" barrier flanked by deep pre- and post-barrier wells. Calculated rate constants for the forward reaction are in reasonable agreement with experiment, suggesting a good representation of the forward barrier. The dynamics of the forward reaction was also investigated using a quasi-classical trajectory method at energies just above the barrier. While the OH bond is found to be a spectator, the HCl product has significant rotational excitation. The reaction proceeds via both direct rebound and stripping mechanisms, leading to backward and sideways scattering. PMID:23968087

  5. Estimation of Joint Forces and Moments for the In-Run and Take-Off in Ski Jumping Based on Measurements with Wearable Inertial Sensors

    Directory of Open Access Journals (Sweden)

    Grega Logar

    2015-05-01

    Full Text Available This study uses inertial sensors to measure ski jumper kinematics and joint dynamics, which was until now only a part of simulation studies. For subsequent calculation of dynamics in the joints, a link-segment model was developed. The model relies on the recursive Newton–Euler inverse dynamics. This approach allowed the calculation of the ground reaction force at take-off. For the model validation, four ski jumpers from the National Nordic center performed a simulated jump in a laboratory environment on a force platform; in total, 20 jumps were recorded. The results fit well to the reference system, presenting small errors in the mean and standard deviation and small root-mean-square errors. The error is under 12% of the reference value. For field tests, six jumpers participated in the study; in total, 28 jumps were recorded. All of the measured forces and moments were within the range of prior simulated studies. The proposed system was able to indirectly provide the values of forces and moments in the joints of the ski-jumpers’ body segments, as well as the ground reaction force during the in-run and take-off phases in comparison to the force platform installed on the table. Kinematics assessment and estimation of dynamics parameters can be applied to jumps from any ski jumping hill.

  6. Estimation of joint forces and moments for the in-run and take-off in ski jumping based on measurements with wearable inertial sensors.

    Science.gov (United States)

    Logar, Grega; Munih, Marko

    2015-01-01

    This study uses inertial sensors to measure ski jumper kinematics and joint dynamics, which was until now only a part of simulation studies. For subsequent calculation of dynamics in the joints, a link-segment model was developed. The model relies on the recursive Newton-Euler inverse dynamics. This approach allowed the calculation of the ground reaction force at take-off. For the model validation, four ski jumpers from the National Nordic center performed a simulated jump in a laboratory environment on a force platform; in total, 20 jumps were recorded. The results fit well to the reference system, presenting small errors in the mean and standard deviation and small root-mean-square errors. The error is under 12% of the reference value. For field tests, six jumpers participated in the study; in total, 28 jumps were recorded. All of the measured forces and moments were within the range of prior simulated studies. The proposed system was able to indirectly provide the values of forces and moments in the joints of the ski-jumpers' body segments, as well as the ground reaction force during the in-run and take-off phases in comparison to the force platform installed on the table. Kinematics assessment and estimation of dynamics parameters can be applied to jumps from any ski jumping hill. PMID:25985167

  7. Strong Force

    CERN Document Server

    Without the strong force, there could be no life. The carbon in living matter is synthesised in stars via the strong force. Lighter atomic nuclei become bound together in a process called nuclear fusion. A minor change in this interaction would make life impossible. As its name suggests, the strong force is the most powerful of the 4 forces, yet its sphere of influence is limited to within the atomic nucleus. Indeed it is the strong force that holds together the quarks inside the positively charged protons. Without this glue, the quarks would fly apart repulsed by electromagnetism. In fact, it is impossible to separate 2 quarks : so much energy is needed, that a second pair of quarks is produced. Text for the interactive: Can you pull apart the quarks inside a proton?

  8. Design Optimization of Ground Clearance of Domestic Cars

    Directory of Open Access Journals (Sweden)

    Debojyoti Mitra

    2010-07-01

    Full Text Available Drag and lift forces plays a vital role in the performance and stability of vehicles. Less drag means less fuel consumption and hence less vehicular pollution. Also, lower lift force means higher chance of adhesion of the car body with the ground causing less overturning of the vehicle, which improves the vehicle performance. Both drag and lift forces can be manipulated by varying the ground clearance of the cars. The present study concentrates on studying the effect of ground clearance on these aerodynamic forces experimentally. Wind tunnel studies with a notch-back car model revealed increase in drag and decrease in lift with increase in ground clearance. Therefore, optimization is required for designing the best ground clearance and a preferable value of the same is thus obtained.

  9. Weak Force

    CERN Multimedia

    Without the weak force, the sun wouldn't shine. The weak force causes beta decay, a form of radioactivity that triggers nuclear fusion in the heart of the sun. The weak force is unlike other forces: it is characterised by disintegration. In beta decay, a down quark transforms into an up quark and an electron is emitted. Some materials are more radioactive than others because the delicate balance between the strong force and the weak force varies depending on the number of particles in the atomic nucleus. We live in the midst of a natural radioactive background that varies from region to region. For example, in Cornwall where there is a lot of granite, levels of background radiation are much higher than in the Geneva region. Text for the interactive: Move the Geiger counter to find out which samples are radioactive - you may be surprised. It is the weak force that is responsible for the Beta radioactivity here. The electrons emitted do not cross the plastic cover. Why do you think there is some detected radioa...

  10. On Grounding of Fast Ships

    DEFF Research Database (Denmark)

    Simonsen, Bo Cerup; Pedersen, Preben Terndrup

    1997-01-01

    The paper deals with analysis of grounding of high-speed crafts. It is the purpose to present a comprehensive mathematical model for calculation of the overall dynamic ship response during grounding. This procedure is applied to derive the motions, the time varying sectional forces and the local loads during grounding on plane, sloping, sandy bottoms for six different designs of fast monohull ships made from steel, aluminium or GRP sandwich materials. The results show that the effect of the hull flexibility is to reduce the overall dynamic sectional loads on the hull girder. The considered numerical examples also indicate that, even with impact speeds of 40 knots against a 1:10 sloping bottom, the global strength of the hull girder is not exceeded by the grounding induced loads.For the local deformation of high-speed ship hulls at the point of contact withthe ground, the paper presents experimental results from crushing tests of aluminium hull girder components with realistic full-scale scantlings. A comparison with existing simplified calculation procedures for ductile metallic structures show that these procedures cannot be used to predict the crushing behaviour of the fore body of high speed ships.

  11. Frictional forces and ankle fractures in sport.

    OpenAIRE

    Menck, H.; Jørgensen, U.

    1983-01-01

    The frictional forces between the sports footwear and the ground can induce distorsion trauma to the lower extremity. Two cases are reported in which fractures about the ankle are related to this friction. An adjustment and reduction of the frictional forces are recommendable.

  12. ``Force,'' ontology, and language

    Science.gov (United States)

    Brookes, David T.; Etkina, Eugenia

    2009-06-01

    We introduce a linguistic framework through which one can interpret systematically students’ understanding of and reasoning about force and motion. Some researchers have suggested that students have robust misconceptions or alternative frameworks grounded in everyday experience. Others have pointed out the inconsistency of students’ responses and presented a phenomenological explanation for what is observed, namely, knowledge in pieces. We wish to present a view that builds on and unifies aspects of this prior research. Our argument is that many students’ difficulties with force and motion are primarily due to a combination of linguistic and ontological difficulties. It is possible that students are primarily engaged in trying to define and categorize the meaning of the term “force” as spoken about by physicists. We found that this process of negotiation of meaning is remarkably similar to that engaged in by physicists in history. In this paper we will describe a study of the historical record that reveals an analogous process of meaning negotiation, spanning multiple centuries. Using methods from cognitive linguistics and systemic functional grammar, we will present an analysis of the force and motion literature, focusing on prior studies with interview data. We will then discuss the implications of our findings for physics instruction.

  13. Reactive processes in gas phase Na(+)-iso-C3H7Cl collisions: experimental guided-ion-beam and ab initio studies of the reactions on the ground singlet potential surface of the system up to 12.00 eV.

    Science.gov (United States)

    Aguilar, J; Lucas, J M; de Andrés, J; Albertí, M; Bassi, D; Aguilar, A

    2011-11-01

    Reactive processes, taking place when sodium ions collide with neutral iso-C(3)H(7)Cl molecules in the 0.02-12.00 eV range of energies in the center of mass frame, have been studied using an octopole radiofrequency guided-ion-beam apparatus developed in our laboratory. A dehydrohalogenation reaction channel leading to Na(C(3)H(6))(+) formation has been observed up to 1.00 eV while another process producing NaHCl(+) continues up to 4.00 eV. Furthermore, C(3)H(7)(+) formation resulting from decomposition of the reactants, ion-molecule adducts, has also been observed as well as its decomposition into C(2)H(3)(+) on increasing collision energy. Cross-section energy dependences for all these reactions have been obtained in absolute units. The ab initio electronic structure calculations have been done at the MP2 level for the colliding system ground singlet potential surface, giving information on the reactive surface main topological features. From the surface reactants side to the products' one, different potential wells and barriers have been characterized and their connectivity along the reaction evolution has been established using the intrinsic-reaction-coordinate method, thus interpreting the dynamical evolution of the reactants' collision complex to products. Experimental results demonstrate that NaHCl(+) can be produced via different channels. Reaction rate constants at 308.2 K for both dehydrohalogenation reactions have been calculated from measured excitation functions. It has been also confirmed that the reactants adduct decomposition giving C(3)H(7)(+) and NaCl takes place on the same potential surface. A qualitative interpretation of the experimental results in terms of ab initio calculations is also given. PMID:21947277

  14. Discussing the theological grounds of moral principles.

    Science.gov (United States)

    Heller, Jan C

    2005-01-01

    Discussing the theological beliefs that ground Catholic moral principles can make some people uncomfortable, even while others will appreciate it. But these reactions will sometimes be revealed not as the emotions they are, but as objections to the relative independence or dependence of morality on foundational beliefs. In the end, context should dictate whether one displays the theological beliefs that ground Catholic moral principles. PMID:16273738

  15. Force direction pattern stabilizes sagittal plane mechanics of human walking.

    Science.gov (United States)

    Gruben, Kreg G; Boehm, Wendy L

    2012-06-01

    The neural control and mechanics of human bipedalism are inadequately understood. The variable at the interface of neural control and body mechanics that is key to upright posture during human walking is the force of the ground on the foot (ground reaction force, F). We present a model that predicts sagittal plane F direction as passing through a divergent point (DP) fixed in a reference frame attached to the person. Four reference frames were tested to identify which provided the simplest and most accurate description of F direction. For all reference frames, the DP model predicted nearly all the observed variation in F direction and whole body angular momentum during single leg stance. The reference frame with vertical orientation and with origin on the pelvis provided the best combination of accuracy and simplicity. The DP was located higher than the CM and the predicted F produced a pattern of torque about the CM that caused body pitch oscillations that disrupted upright posture. Despite those oscillations, that torque was evidence of a stability mechanism that may be a critical component enabling humans to remain upright while walking and performing other tasks. PMID:21871681

  16. Action-reaction at a distance

    Science.gov (United States)

    Brand, Howard

    2002-03-01

    Lenz's law is used to demonstrate that Newton's third law includes forces acting at a distance. The action-reaction pair is the force on a magnet falling through a conducting tube at terminal velocity, and a force on the tube.

  17. XMM Future Operational Ground Segment

    Science.gov (United States)

    Finn, T.; Kirsch, M.; Schmidt, F.; Pfeil, N.; Vasconcellos, A.; Martin, J.

    2014-07-01

    XMM-Newton has been operating for 14 years which have been characterised by an extraordinary scientific return leading to it being considered as one of the most important scientific missions operated by ESA. XMM-Newton has outlived its original operating lifetime and this has led to a new array of technical challenges which new software and operating strategies have greatly mitigated and have enabled XMM-Newton to continue to perform optimally. XMM-Newton relies on reaction wheels and thrusters to manoeuvre consuming on -board fuel and limiting XMM-Newtons operating life. As a result a new operating concept for the reaction wheels has been devised and reduces the fuel consumption by approximately 50% potentially allowing XMM-Newton to operate until 2028. This extension leads to a new set of challenges; firstly, a change in the orbital inclination causes XMM-Newtons ground station Kourou to develop a gap in coverage around perigee for a period of 5 years from mid-2014 and secondly, XMM-Newtons second prime ground station, Perth, is to be decommissioned at the end of 2015 due to regulation governing civil spectrum usage. This paper illustrates how these issues are resoled from a ground segment perspective and when implemented will ensure XMM-Newtons continuance into the next decade.

  18. TARDEC's Intelligent Ground Systems overview

    Science.gov (United States)

    Jaster, Jeffrey F.

    2009-05-01

    The mission of the Intelligent Ground Systems (IGS) Area at the Tank Automotive Research, Development and Engineering Center (TARDEC) is to conduct technology maturation and integration to increase Soldier robot control/interface intuitiveness and robotic ground system robustness, functionality and overall system effectiveness for the Future Combat System Brigade Combat Team, Robotics Systems Joint Project Office and game changing capabilities to be fielded beyond the current force. This is accomplished through technology component development focused on increasing unmanned ground vehicle autonomy, optimizing crew interfaces and mission planners that capture commanders' intent, integrating payloads that provide 360 degree local situational awareness and expanding current UGV tactical behavior, learning and adaptation capabilities. The integration of these technology components into ground vehicle demonstrators permits engineering evaluation, User assessment and performance characterization in increasingly complex, dynamic and relevant environments to include high speed on road or cross country operations, all weather/visibility conditions and military operations in urban terrain (MOUT). Focused testing and experimentation is directed at reducing PM risk areas (safe operations, autonomous maneuver, manned-unmanned collaboration) and transitioning technology in the form of hardware, software algorithms, test and performance data, as well as User feedback and lessons learned.

  19. Ground water and energy

    Energy Technology Data Exchange (ETDEWEB)

    1980-11-01

    This national workshop on ground water and energy was conceived by the US Department of Energy's Office of Environmental Assessments. Generally, OEA needed to know what data are available on ground water, what information is still needed, and how DOE can best utilize what has already been learned. The workshop focussed on three areas: (1) ground water supply; (2) conflicts and barriers to ground water use; and (3) alternatives or solutions to the various issues relating to ground water. (ACR)

  20. From grounding to supervenience?

    OpenAIRE

    Leuenberger, S.

    2013-01-01

    The concept of supervenience and a regimented concept of grounding are often taken to provide rival explications of pre-theoretical concepts of dependence and determination. Friends of grounding typically point out that supervenience claims do not entail corresponding grounding claims. Every fact supervenes on itself, but is not grounded in itself, and the fact that a thing exists supervenes on the fact that its singleton exists, but is not grounded in it. Common lore has it, though, that gro...

  1. The Path Integral Monte Carlo Calculation of Electronic Forces

    CERN Document Server

    Zong, F; Zong, Fenghua

    1998-01-01

    We describe a method to evaluate electronic forces by Path Integral Monte Carlo (PIMC). Electronic correlations, as well as thermal effects, are included naturally in this method. For fermions, a restricted approach is used to avoid the ``sign'' problem. The PIMC force estimator is local and has a finite variance. We applied this method to determine the bond length of H$_2$ and the chemical reaction barrier of H+H$_2\\longrightarrow $H$_2$+H. At low temperature, good agreement is obtained with ground state calculations. We studied the proton-proton interaction in an electron gas as a simple model for hydrogen impurities in metals. We calculated the force between the two protons at two electronic densities corresponding to Na ($r_s=3.93$) and Al ($r_s=2.07$) using a supercell with 38 electrons. The result is compared to previous calculations. We also studied the effect of temperature on the proton-proton interaction. At very high temperature, our result agrees with the Debye screening of electrons. As temperatu...

  2. An ergonomic modular foot platform for isometric force/torque measurements in poststroke functional assessment: A pilot study

    Directory of Open Access Journals (Sweden)

    Stefano Mazzoleni, PhD

    2012-08-01

    Full Text Available The main goal of this article is to present the design, technical development, and preliminary validation of an innovative mechatronic device for force/torque measurements taken from the human foot using pilot data. The device, formed by a mobile platform equipped with two six-axis force/torque sensors, was used to perform accurate quantitative measurements during isometric exercises, aimed at performing functional assessment tests in poststroke patients undergoing a rehabilitation treatment. Results from pilot data provide a validation of the device. A large clinical trial has been planned to test whether the platform can be used in the clinical practice. We suggest that measurements of ground reaction forces taken from the foot of poststroke patients during the initiation of activities of daily living tasks can provide information about their motor recovery and enlighten possible areas of application, ranging from isometric motor exercise in neurorehabilitation to foot-based human-machine interface.

  3. An ergonomic modular foot platform for isometric force/torque measurements in poststroke functional assessment: a pilot study.

    Science.gov (United States)

    Mazzoleni, Stefano; Van Vaerenbergh, Jo; Stokes, Emma; Fazekas, Gábor; Dario, Paolo; Guglielmelli, Eugenio

    2012-01-01

    The main goal of this article is to present the design, technical development, and preliminary validation of an innovative mechatronic device for force/torque measurements taken from the human foot using pilot data. The device, formed by a mobile platform equipped with two six-axis force/torque sensors, was used to perform accurate quantitative measurements during isometric exercises, aimed at performing functional assessment tests in poststroke patients undergoing a rehabilitation treatment. Results from pilot data provide a validation of the device. A large clinical trial has been planned to test whether the platform can be used in the clinical practice. We suggest that measurements of ground reaction forces taken from the foot of poststroke patients during the initiation of activities of daily living tasks can provide information about their motor recovery and enlighten possible areas of application, ranging from isometric motor exercise in neurorehabilitation to foot-based human-machine interface. PMID:23299264

  4. Heavy ion ?-transfer reactions

    International Nuclear Information System (INIS)

    Excitation functions and angular distributions have been measured at energies near the Coulomb barrier for the elastic scattering of 16O from 16O and for the (16O,12C) ?-transfer reaction to the ground state and first excited state of 20Ne. The experimental work was performed using the EN Tandem Van de Graaff accelerator of the University of the Witwatersrand. The reaction cross sections were measured with the aid of a ?E-E detector telescope employing a gas ionisation chamber. The transfer reaction data were analysed in terms of an exact-finite range DWBA calcultion assuming the four nucleons to be transferred directly as a cluster. The 16O+16O elastic scattering is characterised by weak absorption which leads to a sensitivity of the DWBA calculations to the form of the optical potentials in the surface regions of the interaction. For this reason the effects of replacing the Woods-Saxon real nuclear potential and the point-charge Coulomb potential by folding-model forms were investigated. In general improved fits to the reaction data were obtained when using the folded potentials, suggesting that these potentials provide a better description of the interaction at the surface. No evidence quasimolecular resonance was observed in the transfer reaction excitation functions. The spectroscopic factors extracted from the transfer reaction angular distributions were found to be strongly dependentions were found to be strongly dependent on the form optical potentials, and the potential well binding the transferred ?-particle

  5. Magnificent Ground Water Connection

    Science.gov (United States)

    The Magnificent Ground Water Connection is a compilation of ground water-related activities for teaching and learning purposes. The teacher's activity guide is applicable to a wide range of subject matter and the ground water theme is integrated into stories, songs, math, social studies, art and writing. The topics include basic concepts of the water cycle, water distribution, treatment and stewardship. Other subjects include the water cycle and water conservation, New England's ground water resources, ground water contamination and protection. Sections are also available for wetlands, ground water, marine debris, waster, air quality, acid rain, and energy. Users can also access an on-line lending library for educational materials and videos.

  6. Enzyme Reactions

    Science.gov (United States)

    Minerva Deland School

    2011-10-03

    This video shows an enzyme reaction lab. The teacher demonstrates how the enzyme, catalase, reacts with hydrogen peroxide (a substrate found in cells). The teacher first demonstrates a normal enzyme reaction. He or she then goes on to show how manipulating temperature and pH will affect the reaction of an enzyme.

  7. Friction Force

    Science.gov (United States)

    AMPS GK-12 Program,

    Students use LEGO® MINDSTORMS® robotics to help conceptualize and understand the force of friction. Specifically, they observe how different surfaces in contact result in different frictional forces. A LEGO robot is constructed to pull a two-wheeled trailer made of LEGO parts. The robot is programmed to pull the trailer 10 feet and trial runs are conducted on smooth and textured surfaces. The speed and motor power of the robot is kept constant in all trials so students observe the effect of friction between various combinations of surfaces and trailer wheels. To apply what they learn, students act as engineers and create the most effective car by designing the most optimal tires for given surface conditions.

  8. Travelling-stripe forcing generates hexagonal patterns

    OpenAIRE

    Míguez, D G; Nicola, E. M.; Muñuzuri, A. P.; Casademunt i Viader, Jaume; Sagués i Mestre, Francesc; Kramer, L.

    2004-01-01

    We study the response of Turing stripe patterns to a simple spatiotemporal forcing. This forcing has the form of a traveling wave and is spatially resonant with the characteristic Turing wavelength. Experiments conducted with the photosensitive chlorine dioxide-iodine-malonic acid reaction reveal a striking symmetry-breaking phenomenon of the intrinsic striped patterns giving rise to hexagonal lattices for intermediate values of the forcing velocity. The phenomenon is understood in the framew...

  9. Hydrodynamic forces effecting steam bubbles while boiling

    International Nuclear Information System (INIS)

    Hydrodynamic force values, effecting steam bubbles, on the water surface while boiling, n-pentane and methanol are investigated on the base of ''action function'' notion introduction. Grounded is use necessity while determining hydrodynamic forces of certain bubbles increase laws. It is shown, that depending on the nature of the acting hydrodynamic forces, the investigated steam bubbles can be divided into two groups with different separation conditions from the boiling surface. It is supposed, that the first group bubble growth is essentially influenced by the microlayer of the liquid under the bubble. Separation of the babbles of the second group is determined by evaporation force action and by the bubble dynamic instability

  10. Ground stiffness measurement by the continuous surface wave test

    OpenAIRE

    Heymann, Gerhard

    2007-01-01

    The continuous surface wave (CSW) test is a seismic technique for determining ground stiffness by measuring the velocity of Rayleigh wave propagation along the ground surface. A sinusoidal force is generated by a shaker placed on the ground surface and the response is detected by an array of geophones also at the surface. Measurements are made for a range of shaker frequencies thereby allowing a profile of stiffness with depth to be established. The continuous surface wave test is performed r...

  11. Within- and between-session reliability of power, force, and rate of force development during the power clean.

    Science.gov (United States)

    Comfort, Paul

    2013-05-01

    Although there has been extensive research regarding the power clean, its application to sports performance, and use as a measure of assessing changes in performance, no research has determined the reliability assessing the kinetics of the power clean across testing session. The aim of this study was to determine the within- and between-session reliability of kinetic variables during the power clean. Twelve professional rugby league players (age 24.5 ± 2.1 years; height 182.86 ± 6.97 cm; body mass 92.85 ± 5.67 kg; 1 repetition maximum [1RM] power clean 102.50 ± 10.35 kg) performed 3 sets of 3 repetitions of power cleans at 70% of their 1RM, while standing on a force plate, to determine within-session reliability and repeated on 3 separate occasions to determine reliability between sessions. Intraclass correlation coefficients revealed a high reliability within- (r ? 0.969) and between-sessions (r ? 0.988). Repeated-measures analysis of variance showed no significant difference (p > 0.05) in peak vertical ground reaction force, rate of force development, and peak power between sessions, with small standard error of the measurements and smallest detectable differences for each kinetic variable (3.13 and 8.68 N; 84.39 and 233.93 N·s; 24.54 and 68.01 W, respectively). Therefore, to identify a meaningful change in performance, the strength and conditioning coach should look for a change in peak force ?8.68 N, rate of force development ?24.54 N·s, and a change in peak power ?68.01 W to signify an adaptive response to training, which is greater than the variance between sessions, in trained athletes proficient at performing the power clean. PMID:22843043

  12. Electrical Subsurface Grounding Analysis

    International Nuclear Information System (INIS)

    The purpose and objective of this analysis is to determine the present grounding requirements of the Exploratory Studies Facility (ESF) subsurface electrical system and to verify that the actual grounding system and devices satisfy the requirements

  13. Electrical Subsurface Grounding Analysis

    Energy Technology Data Exchange (ETDEWEB)

    J.M. Calle

    2000-11-01

    The purpose and objective of this analysis is to determine the present grounding requirements of the Exploratory Studies Facility (ESF) subsurface electrical system and to verify that the actual grounding system and devices satisfy the requirements.

  14. Electroweak reactions with light nuclei

    Directory of Open Access Journals (Sweden)

    Bacca S.

    2010-04-01

    Full Text Available The investigation of light nuclei with ab-initio methods provides an optimal setting to probe our knowledge on nuclear forces, because the few-nucleon problem can be solved accurately. Nucleons interact not only in pairs but also via many-body forces. Theoretical e?orts need to be taken towards the identi?cation of nuclear observables sensitive to the less known many-nucleon forces. Electromagnetic reactions can potentially provide useful information on this. We present results on photo-absorption and electron scattering o? light nuclei, emphasizing the role of three-body forces and the comparison with experimental data. On the other hand, reactions induced by weak probes, like neutrino interactions with nucleonic matter, are relevant to astrophysics and can be calculated with few-body techniques. In this case, since often no experiment is possible, ab-initio predictions provide valuable input for astrophysical simulations.

  15. The ground based plan

    International Nuclear Information System (INIS)

    The paper presents a report of ''The Ground Based Plan'' of the United Kingdom Science and Engineering Research Council. The ground based plan is a plan for research in astronomy and planetary science by ground based techniques. The contents of the report contains a description of:- the scientific objectives and technical requirements (the basis for the Plan), the present organisation and funding for the ground based programme, the Plan, the main scientific features and the further objectives of the Plan. (U.K.)

  16. Constructivist Grounded Theory?

    Directory of Open Access Journals (Sweden)

    Barney G. Glaser, PhD, Hon. PhD

    2012-06-01

    Full Text Available AbstractI refer to and use as scholarly inspiration Charmaz’s excellent article on constructivist grounded theory as a tool of getting to the fundamental issues on why grounded theory is not constructivist. I show that constructivist data, if it exists at all, is a very, very small part of the data that grounded theory uses.

  17. The reliability of linear position transducer and force plate measurement of explosive force-time variables during a loaded jump squat in elite athletes.

    Science.gov (United States)

    Hansen, Keir T; Cronin, John B; Newton, Michael J

    2011-05-01

    The best method of assessing muscular force qualities during isoinertial stretch shorten cycle lower body movements remains a subject of much debate. This study had 2 purposes: Firstly, to calculate the interday reliability of peak force (PF) measurement and a variety of force-time measures, and, secondly, to compare the reliability of the 2 most common technologies for measuring force during loaded jump squats, the linear position transducer (PT), and the force plate (FP). Twenty-five male elite level rugby union players performed 3 rebound jump squats with a 40-kg external load on 2 occasions 1 week apart. Vertical ground reaction forces (GRFs) were directly measured via an FP, and force was differentiated from position data collected using a PT. From these data, a number of force-time variables were calculated for both the FP and PT. Intraclass correlation coefficient (ICC), coefficient of variation (CV), and percent change in the mean were used as measures of between-session reliability. Additionally, Pearson's product moment correlation coefficients were used to investigate intercorrelations between variables and technologies. Both FP and PT were found to be a reliable means of measuring PF (ICC = 0.88-0.96, CV = 2.3-4.8%), and the relationship between the 2 technologies was very high and high for days 1 and 2, respectively (r = 0.67-0.88). Force-time variables calculated from FP data tended to have greater relative and absolute consistency (ICC = 0.70-0.96, CV = 5.1-51.8%) than those calculated from differentiated PT data (ICC = 0.18-0.95, CV = 7.7-93.6%). Intercorrelations between variables ranged from trivial to practically perfect (r = 0.00-1.00). It was concluded that PF can be measured reliably with both FP and PT technologies, and these measurements are related. A number of force-time values can also be reliably calculated via the use of GRF data. Although some of these force-time variables can be reliably calculated using position data, variation of measurement is generally greater when using position data to calculate force. PMID:21116199

  18. TFTR grounding system

    International Nuclear Information System (INIS)

    This paper outlines the rationale and concepts which led to the TFTR grounding system. Examples of induced voltages and voltage gradients expected during plasma disruption are presented. The methods of voltage gradient control and grounding connections are described. In addition to conventional grounding arrangements for equipment housings, fences, cable trays, special requirements for the vacuum vessel, TFTR coil cases, PF coil surfaces and umbrella-like support structures are described. Arrangements for diagnostic grounds which are designed to minimize interference from the facility ground also are described

  19. Nuclear Reactions

    OpenAIRE

    Bertulani, C.A.(Texas A & M University-Commerce, PO Box 3011, Commerce, Texas, 75429, USA)

    2009-01-01

    Nuclear reactions generate energy in nuclear reactors, in stars, and are responsible for the existence of all elements heavier than hydrogen in the universe. Nuclear reactions denote reactions between nuclei, and between nuclei and other fundamental particles, such as electrons and photons. A short description of the conservation laws and the definition of basic physical quantities is presented, followed by a more detailed account of specific cases: (a) formation and decay o...

  20. 46 CFR 183.376 - Grounded distribution systems (neutral grounded).

    Science.gov (United States)

    2010-10-01

    ... 2010-10-01 false Grounded distribution systems (neutral grounded). 183.376...ELECTRICAL INSTALLATION Power Sources and Distribution Systems § 183.376 Grounded distribution systems (neutral grounded). (a) If...

  1. 46 CFR 120.376 - Grounded distribution systems (Neutral grounded).

    Science.gov (United States)

    2010-10-01

    ... 2010-10-01 false Grounded distribution systems (Neutral grounded). 120.376...ELECTRICAL INSTALLATION Power Sources and Distribution Systems § 120.376 Grounded distribution systems (Neutral grounded). (a) If...

  2. Rapid grounding line migration induced by internal ice stream variability

    Science.gov (United States)

    Robel, A. A.; Schoof, C.; Tziperman, E.

    2014-11-01

    Observations indicate that the grounding line position of West Antarctica is sensitive to both forced and unforced ice stream variabilities. This study endeavors to characterize and understand unforced ice stream variability and associated grounding line migration. We use a flowline ice stream model with an undrained plastic bed, lateral shear stresses, and a stretched grid refined in the grounding zone. This model exhibits parameter space structure and hysteresis behavior similar to simpler ice stream models. Low prescribed temperature at the ice surface or weak geothermal heating produces thermal oscillations between active and stagnant phases. As in previous spatially resolved ice flow models, thermal activation propagates as an "activation wave." This model's fine resolution of the grounding zone allows for accurate simulations of transient, unforced grounding line migration. Upstream of the grounding zone, horizontal grid spacing of 1 km is required to accurately resolve activation waves. Activation waves induce the grounding line to migrate over 100 km at a rate that can exceed 1 km/yr. This is followed during the active phase by retreat, which then continues for the duration of the stagnant phase. Grounding line retreat is the result of a negative mass balance near the grounding line but is not necessarily associated with negative mass balance for the entire ice stream in our simulations of internal variability. The novel approach and experiments described in this study show that there can be large excursions in grounding line position in the absence of either external forcing or retrograde slopes.

  3. Reaction Wheel Disturbance Model Extraction Software Project

    National Aeronautics and Space Administration — Reaction wheel mechanical noise is one of the largest sources of disturbance forcing on space-based observatories. Such noise arises from mass imbalance, bearing...

  4. Performance and Stability of a Winged Vehicle in Ground Effect

    CERN Document Server

    de Divitiis, Nicola

    2009-01-01

    Present work deals with the dynamics of vehicles which intentionally operate in the ground proximity. The dynamics in ground effect is influenced by the vehicle orientation with respect to the ground, since the aerodynamic force and moment coefficients, which in turn depend on height and angle of attack, also vary with the Euler angles. This feature, usually neglected in the applications, can be responsible for sizable variations of the aircraft performance and stability. A further effect, caused by the sink rate, determines unsteadiness that modifies the aerodynamic coefficients. In this work, an analytical formulation is proposed for the force and moment calculation in the presence of the ground and taking the aircraft attitude and sink rate into account. The aerodynamic coefficients are firstly calculated for a representative vehicle and its characteristics in ground effect are investigated. Performance and stability characteristics are then discussed with reference to significant equilibrium conditions, w...

  5. Grounded running in quails: simulations indicate benefits of observed fixed aperture angle between legs before touch-down.

    Science.gov (United States)

    Andrada, Emanuel; Rode, Christian; Blickhan, Reinhard

    2013-10-21

    Many birds use grounded running (running without aerial phases) in a wide range of speeds. Contrary to walking and running, numerical investigations of this gait based on the BSLIP (bipedal spring loaded inverted pendulum) template are rare. To obtain template related parameters of quails (e.g. leg stiffness) we used x-ray cinematography combined with ground reaction force measurements of quail grounded running. Interestingly, with speed the quails did not adjust the swing leg's angle of attack with respect to the ground but adapted the angle between legs (which we termed aperture angle), and fixed it about 30ms before touchdown. In simulations with the BSLIP we compared this swing leg alignment policy with the fixed angle of attack with respect to the ground typically used in the literature. We found symmetric periodic grounded running in a simply connected subset comprising one third of the investigated parameter space. The fixed aperture angle strategy revealed improved local stability and surprising tolerance with respect to large perturbations. Starting with the periodic solutions, after step-down step-up or step-up step-down perturbations of 10% leg rest length, in the vast majority of cases the bipedal SLIP could accomplish at least 50 steps to fall. The fixed angle of attack strategy was not feasible. We propose that, in small animals in particular, grounded running may be a common gait that allows highly compliant systems to exploit energy storage without the necessity of quick changes in the locomotor program when facing perturbations. PMID:23831138

  6. Neutrino nuclear response and photo nuclear reaction

    OpenAIRE

    Ejiri, H.; Titov, A. I.; Boswell, M.; Young, A.

    2013-01-01

    Photo nuclear reactions are shown to be used for studying neutrino/weak nuclear responses involved in astro-neutrino nuclear interactions and double beta decays. Charged current weak responses for ground and excited states are studied by using photo nuclear reactions through isobaric analog states of those states, while neutral current weak responses for excited states are studied by using photo nuclear reactions through the excited states. The weak interaction strengths are...

  7. Classical Helium Atom with Radiation Reaction

    OpenAIRE

    Carati, Andrea; Galgani, Luigi

    2011-01-01

    We study a classical model of Helium atom in which, in addition to the Coulomb forces, the radiation reaction forces are taken into account. This modification brings in the model a new qualitative feature of a global character. Indeed, as pointed out by Dirac, in any model of classical electrodynamics of point particles involving radiation reaction one has to eliminate, from the a priori conceivable solutions of the problem, those corresponding to the emission of an infinite...

  8. Immediate effects of a single inclined treadmill walking session on level ground walking in individuals after stroke.

    Science.gov (United States)

    Phadke, Chetan P

    2012-04-01

    Propulsion and paretic plantar flexor activity after stroke are deficient in walking. This study examined whether walking on an inclined treadmill increased muscle activity and whether it resulted in increased propulsion and muscle activity during level ground walking. Nine people with hemiparesis caused by stroke and nine healthy controls participated. The participants walked at treadmill inclines of 0, 2.5, and 5 degrees for 5 mins at each level, for a total walking period of 15 mins. Surface electromyograms were obtained from the tibialis anterior and medial gastrocnemius muscles. Anterior-posterior ground reaction forces and electromyograms were recorded during overground walking before, immediately after, and 20 mins after inclined treadmill walking. Plantar flexor activity was significantly greater at 2.5 and 5 degree incline compared with no incline bilaterally in healthy controls and in the nonparetic side of people with stroke (P 0.245). Electromyograms in control and stroke groups and the propulsive force in controls during overground walking were not significantly different before and after inclined treadmill walking. Overground propulsive forces after inclined treadmill walking in the stroke group were marginally higher in the nonparetic side (P Future tests should study the effect of higher inclines and faster treadmill speeds on paretic electromyogram activity. PMID:22173086

  9. The Grounded Theory Bookshelf

    Directory of Open Access Journals (Sweden)

    Vivian B. Martin, Ph.D.

    2005-03-01

    Full Text Available Bookshelf will provide critical reviews and perspectives on books on theory and methodology of interest to grounded theory. This issue includes a review of Heaton’s Reworking Qualitative Data, of special interest for some of its references to grounded theory as a secondary analysis tool; and Goulding’s Grounded Theory: A practical guide for management, business, and market researchers, a book that attempts to explicate the method and presents a grounded theory study that falls a little short of the mark of a fully elaborated theory.Reworking Qualitative Data, Janet Heaton (Sage, 2004. Paperback, 176 pages, $29.95. Hardcover also available.

  10. Relational grounding facilitates development of scientifically useful multiscale models

    Directory of Open Access Journals (Sweden)

    Lam Tai

    2011-09-01

    Full Text Available Abstract We review grounding issues that influence the scientific usefulness of any biomedical multiscale model (MSM. Groundings are the collection of units, dimensions, and/or objects to which a variable or model constituent refers. To date, models that primarily use continuous mathematics rely heavily on absolute grounding, whereas those that primarily use discrete software paradigms (e.g., object-oriented, agent-based, actor typically employ relational grounding. We review grounding issues and identify strategies to address them. We maintain that grounding issues should be addressed at the start of any MSM project and should be reevaluated throughout the model development process. We make the following points. Grounding decisions influence model flexibility, adaptability, and thus reusability. Grounding choices should be influenced by measures, uncertainty, system information, and the nature of available validation data. Absolute grounding complicates the process of combining models to form larger models unless all are grounded absolutely. Relational grounding facilitates referent knowledge embodiment within computational mechanisms but requires separate model-to-referent mappings. Absolute grounding can simplify integration by forcing common units and, hence, a common integration target, but context change may require model reengineering. Relational grounding enables synthesis of large, composite (multi-module models that can be robust to context changes. Because biological components have varying degrees of autonomy, corresponding components in MSMs need to do the same. Relational grounding facilitates achieving such autonomy. Biomimetic analogues designed to facilitate translational research and development must have long lifecycles. Exploring mechanisms of normal-to-disease transition requires model components that are grounded relationally. Multi-paradigm modeling requires both hyperspatial and relational grounding.

  11. Relational grounding facilitates development of scientifically useful multiscale models.

    Science.gov (United States)

    Hunt, C Anthony; Ropella, Glen E P; Lam, Tai ning; Gewitz, Andrew D

    2011-01-01

    We review grounding issues that influence the scientific usefulness of any biomedical multiscale model (MSM). Groundings are the collection of units, dimensions, and/or objects to which a variable or model constituent refers. To date, models that primarily use continuous mathematics rely heavily on absolute grounding, whereas those that primarily use discrete software paradigms (e.g., object-oriented, agent-based, actor) typically employ relational grounding. We review grounding issues and identify strategies to address them. We maintain that grounding issues should be addressed at the start of any MSM project and should be reevaluated throughout the model development process. We make the following points. Grounding decisions influence model flexibility, adaptability, and thus reusability. Grounding choices should be influenced by measures, uncertainty, system information, and the nature of available validation data. Absolute grounding complicates the process of combining models to form larger models unless all are grounded absolutely. Relational grounding facilitates referent knowledge embodiment within computational mechanisms but requires separate model-to-referent mappings. Absolute grounding can simplify integration by forcing common units and, hence, a common integration target, but context change may require model reengineering. Relational grounding enables synthesis of large, composite (multi-module) models that can be robust to context changes. Because biological components have varying degrees of autonomy, corresponding components in MSMs need to do the same. Relational grounding facilitates achieving such autonomy. Biomimetic analogues designed to facilitate translational research and development must have long lifecycles. Exploring mechanisms of normal-to-disease transition requires model components that are grounded relationally. Multi-paradigm modeling requires both hyperspatial and relational grounding. PMID:21951817

  12. Dispersive forces on bodies and atoms: a unified approach

    OpenAIRE

    Raabe, Christian; Welsch, Dirk-Gunnar

    2006-01-01

    A unified approach to the calculation of dispersive forces on ground-state bodies and atoms is given. It is based on the ground-state Lorentz force density acting on the charge and current densities attributed to the polarization and magnetization in linearly, locally, and causally responding media. The theory is applied to dielectric macro- and micro-objects, including single atoms. Existing formulas valid for weakly polarizable matter are generalized to allow also for stro...

  13. Convection in Drying and Freezing Ground

    CERN Document Server

    Faizal, Mir

    2012-01-01

    In this paper we analyse the drying of a soil composed of particles, water and solute impurities, and study the occurrence of convective instabilities during evaporation. We find that the main driving force for instability is the formation of a concentration gradient at the soil surface due to the evaporation of water. A similar phenomenon may occur during the thawing of frozen ground in Arctic regions.

  14. Nuclear reactions an introduction

    CERN Document Server

    Paetz gen. Schieck, Hans

    2014-01-01

    Nuclei and nuclear reactions offer a unique setting for investigating three (and in some cases even all four) of the fundamental forces in nature. Nuclei have been shown – mainly by performing scattering experiments with electrons, muons, and neutrinos – to be extended objects with complex internal structures: constituent quarks; gluons, whose exchange binds the quarks together; sea-quarks, the ubiquitous virtual quark-antiquark pairs and, last but not least, clouds of virtual mesons, surrounding an inner nuclear region, their exchange being the source of the nucleon-nucleon interaction.   The interplay between the (mostly attractive) hadronic nucleon-nucleon interaction and the repulsive Coulomb force is responsible for the existence of nuclei; their degree of stability, expressed in the details and limits of the chart of nuclides; their rich structure and the variety of their interactions. Despite the impressive successes of the classical nuclear models and of ab-initio approaches, there is clearly no ...

  15. Low frequency temperature forcing of chemical oscillations.

    Science.gov (United States)

    Novak, Jan; Thompson, Barnaby W; Wilson, Mark C T; Taylor, Annette F; Britton, Melanie M

    2011-07-14

    The low frequency forcing of chemical oscillations by temperature is investigated experimentally in the Belousov-Zhabotinsky (BZ) reaction and in simulations of the Oregonator model with Arrhenius temperature dependence of the rate constants. Forcing with temperature leads to modulation of the chemical frequency. The number of response cycles per forcing cycle is given by the ratio of the natural frequency to the forcing frequency and phase locking is only observed in simulations when this ratio is a whole number and the forcing amplitude is small. The global temperature forcing of flow-distributed oscillations in a tubular reactor is also investigated and synchronisation is observed in the variation of band position with the external signal, reflecting the periodic modulation of chemical oscillations by temperature. PMID:21643566

  16. Drug Reactions

    Science.gov (United States)

    ... can interact with each other or with prescription drugs and cause problems. Supplements, herbal products in teas or tablets, or vitamins may also cause adverse reactions when taken with certain drugs. Be sure to tell your doctor and pharmacist ...

  17. Mechanical interface having multiple grounded actuators

    Science.gov (United States)

    Martin, Kenneth M. (Palo Alto, CA); Levin, Mike D. (Sunnyvale, CA); Rosenberg, Louis B. (Pleasanton, CA)

    1998-01-01

    An apparatus and method for interfacing the motion of a user-manipulable object with a computer system includes a user object physically contacted or grasped by a user. A 3-D spatial mechanism is coupled to the user object, such as a stylus or a medical instrument, and provides three degrees of freedom to the user object. Three grounded actuators provide forces in the three degrees of freedom. Two of the degrees of freedom are a planar workspace provided by a closed-loop linkage of members, and the third degree of freedom is rotation of the planar workspace provided by a rotatable carriage. Capstan drive mechanisms transmit forces between actuators and the user object and include drums coupled to the carriage, pulleys coupled to grounded actuators, and flexible cables transmitting force between the pulleys and the drums. The flexibility of the cable allows the drums to rotate with the carriage while the pulleys and actuators remain fixed to ground. The interface also may include a floating gimbal mechanism coupling the linkage to the user object. The floating gimbal mechanism includes rotatably coupled gimbal members that provide three degrees of freedom to the user object and capstan mechanisms coupled between sensors and the gimbal members for providing enhanced sensor resolution.

  18. Ground State Quantum Computation

    OpenAIRE

    Mizel, Ari; M.W. Mitchell; Cohen, Marvin L.

    1999-01-01

    We formulate a novel ground state quantum computation approach that requires no unitary evolution of qubits in time: the qubits are fixed in stationary states of the Hamiltonian. This formulation supplies a completely time-independent approach to realizing quantum computers. We give a concrete suggestion for a ground state quantum computer involving linked quantum dots.

  19. SEM Ground Spider Interactive

    Science.gov (United States)

    This interactive look at a ground spider's anatomy has close-up images taken using the high-resolution technology of a scanning electron microscope (SEM). By mousing over the labeled images, students can view fifteen features of a generalized ground spider's anatomy.

  20. Airport Ground Staff Scheduling

    DEFF Research Database (Denmark)

    Clausen, Tommy

    2010-01-01

    Modern airports are centers of transportation that service a large number of aircraft and passengers every day. To facilitate this large volume of transportation, airports are subject to many logistical and decision problems that must continuously be solved to make sure each flight and passenger travels safely and efficiently through the airport. When an aircraft lands, a significant number of tasks must be performed by different groups of ground crew, such as fueling, baggage handling and cleaning. These tasks must be complete before the aircraft is able to depart, as well as check-in and security services. These tasks are collectively known as ground handling, and are the major source of activity with airports. The business environments of modern airports are becoming increasingly competitive, as both airports themselves and their ground handling operations are changing to private ownership. As airports are in competition to attract airline routes, efficient and reliable ground handling operations are imperative for the viability and continued growth of both airports and airlines. The increasing liberalization of the ground handling market prompts ground handling operators to increase cost effectiveness and deliver fast and reliable service. This thesis presents models and algorithms for general optimization and decision problems arising within ground handling. The thesis contains an introductory part which provide an overview of the ground handling environment and reviews a series of optimization problems from the specific perspective of airport ground handling. In addition, the thesis contains five scientific papers, which consider specific optimization problems within ground handling in detail. The considered problems range from generalized approaches to workforce planning, to highly detailed scheduling problems arising in the highly dynamic environment of airports.

  1. Gamov-Teller transitions from 14N ground to 14C ground and excited states

    CERN Document Server

    Kanada-En'yo, Yoshiko

    2014-01-01

    Gamov-Teller transitions from the $^{14}$N ground state to the $^{14}$C ground and excited states were investigated, based on the model of antisymmetrized molecular dynamics. The calculated strengths for the allowed transitions to the $0^+$, $1^+$, and $2^+$ states of $^{14}$C were compared with the experimental data measured by high-resolution charge-exchange reactions. The calculated GT transition to the $2^+_1$ state is strong while those to the $0^+_{2,3}$ and $2^+_{2,3}$ states having dominant $2\\hbar\\omega$ excited configurations are relatively weak. The present calculation can not describe the anonymously long life time of $^{14}$C, though the strength of the $^{14}$C ground state is somewhat suppressed because of the cluster (many-body) correlation in the ground states of $^{14}$C and $^{14}$N.

  2. On the entropy of radiation reaction

    CERN Document Server

    Burton, David A

    2013-01-01

    The inexorable development of ever more powerful laser systems has re-ignited interest in electromagnetic radiation reaction and its significance for the collective behaviour of charged matter interacting with intense electromagnetic fields. The classical radiation reaction force on a point electron is non-conservative, and this has led some authors to question the validity of methods used to model ultra-intense laser-matter interactions including radiation reaction. We explain why such concern is unwarranted.

  3. Simple forcing notions and forcing axioms

    OpenAIRE

    Ros?anowski, Andrzej; Shelah, Saharon

    1996-01-01

    In the present paper we are interested in simple forcing notions and Forcing Axioms. A starting point for our investigations was the article [JR1] in which several problems were posed. We answer some of those problems here.

  4. Three-nucleon forces and the trinucleon bound states

    International Nuclear Information System (INIS)

    A summary of the bound-state working group session of the ''International Symposium on the Three-Body Force in the Three-Nucleon System'' is presented. The experimental evidence for three-nucleon forces has centered on two ground state properties: the tritium binding energy and the trinucleon form factors. Both are discussed

  5. Snowboard Jumping, Newton's Second Law and the Force on Landing

    Science.gov (United States)

    O'Shea, Michael J.

    2004-01-01

    An application of Newton's second law to a snowboarder dropping off a vertical ledge shows that the average normal force during landing (force exerted by the ground on the snowboarder) is determined by four factors. It is shown that the flexing of the legs, the softness of the snow, the angle of the landing surface and the forward motion of the…

  6. Electronic transitions and intermolecular forces

    International Nuclear Information System (INIS)

    This thesis describes two different subjects - electronic transitions and intermolecular forces - that are related mainly by the following observation: The wavenumber at which an electronic transition in an atom or molecule occurs, depends on the environment of that atom or molecule. This implies, for instance, that when a molecule becomes solvated its absorption spectrum may be shifted either to the blue or to the red side of the original gasphase spectrum. In part I attention is paid to the experimental aspects of VUV spectroscopy, both in the gasphase and in the condensed phase. In part II a series of papers are presented, dealing with the calculation of intermolecular forces (and some related topics) both for the ground state and for the excited state interactions, using different non-empirical methods. The calculations provide, among other results, a semiquantitative interpretation of the spectral blue shifts encountered in our experiments. (Auth.)

  7. Taxol reactions.

    Science.gov (United States)

    Price, Kursteen S; Castells, Mariana C

    2002-01-01

    Paclitaxel (Taxol) a taxane antineoplastic agent causing irreversible microtubule aggregation with activity against breast, ovarian, lung, head and neck, bladder, testicular, esophageal, endometrial and other less common tumors was derived from the bark of the Pacific yew (Taxus brevifolia). Phase I trials conducted in the late 1980s were almost halted because of the high frequency of hypersensitivity-like reactions. Respiratory distress (dyspnea and/or bronchospasm), hypotension, and angioedema were the major manifestations, but flushing, urticaria, chest, abdomen, and extremity pains were described also. Reactions occurred on first exposure in the majority of cases raising etiologic questions. The vehicle for paclitaxel Cremophor EL (polyoxyethylated castor oil in 50% ethanol) was strongly suspect as a direct (non-immunoglobulin E dependent) histamine releaser. Premedication regimens and longer infusion times lowered the incidence of reactivity allowing phase II and III trials to progress through the early 1990s. The mechanism(s) underlying paclitaxel hypersensitivity-like reactions is still unknown, and clinical data on probable complement and mast cell activation are lacking. The original clinical trial protocols for paclitaxel required discontinuation of therapy for patients who experienced hypersensitivity-like reactions. Here, we review the current etiologic knowledge of these reactions and describe our clinical approach to allow completion of chemotherapy with this powerful plant-derived agent. PMID:12125509

  8. A force calibration standard for magnetic tweezers

    Science.gov (United States)

    Yu, Zhongbo; Dulin, David; Cnossen, Jelmer; Köber, Mariana; van Oene, Maarten M.; Ordu, Orkide; Berghuis, Bojk A.; Hensgens, Toivo; Lipfert, Jan; Dekker, Nynke H.

    2014-12-01

    To study the behavior of biological macromolecules and enzymatic reactions under force, advances in single-molecule force spectroscopy have proven instrumental. Magnetic tweezers form one of the most powerful of these techniques, due to their overall simplicity, non-invasive character, potential for high throughput measurements, and large force range. Drawbacks of magnetic tweezers, however, are that accurate determination of the applied forces can be challenging for short biomolecules at high forces and very time-consuming for long tethers at low forces below ˜1 piconewton. Here, we address these drawbacks by presenting a calibration standard for magnetic tweezers consisting of measured forces for four magnet configurations. Each such configuration is calibrated for two commonly employed commercially available magnetic microspheres. We calculate forces in both time and spectral domains by analyzing bead fluctuations. The resulting calibration curves, validated through the use of different algorithms that yield close agreement in their determination of the applied forces, span a range from 100 piconewtons down to tens of femtonewtons. These generalized force calibrations will serve as a convenient resource for magnetic tweezers users and diminish variations between different experimental configurations or laboratories.

  9. Ground Source Heat Pumps

    OpenAIRE

    Lale Valizade

    2013-01-01

    A heat pump is a device that is able to transfer heat from one fluid at a lower temperature to another at a higher temperature. Ground source heat pumps are generally classified by the type of ground loop. The coefficient of performance (COP) is used to define the heating performance of heat pumps. Both the COP and EER values are valid only at the specific test conditions used in the rating. A ground source pump could reach 450%, compared with an efficient gas boiler of 90% obviously this is ...

  10. An Ignored Mechanism for the Longitudinal Recoil Force in Railguns and Revitalization of the Riemann Force Law

    CERN Document Server

    Su, C C

    2005-01-01

    The electric induction force due to a time-varying current is used to account for the longitudinal recoil force exerted on the rails of railgun accelerators. As observed in the experiments, this induction force is longitudinal to the rails and can be the strongest at the heads of the rails. Besides, for the force due to a closed circuit, it is shown that the Riemann force law, which is based on a potential energy depending on a relative speed and is in accord with Newton's law of action and reaction, can reduce to the Lorentz force law.

  11. Handbook of force transducers

    CERN Document Server

    Stefanescu, Dan Mihai

    2011-01-01

    Part I introduces the basic ""Principles and Methods of Force Measurement"" acording to a classification into a dozen of force transducers types: resistive, inductive, capacitive, piezoelectric, electromagnetic, electrodynamic, magnetoelastic, galvanomagnetic (Hall-effect), vibrating wires, (micro)resonators, acoustic and gyroscopic. Two special chapters refer to force balance techniques and to combined methods in force measurement. Part II discusses the ""(Strain Gauge) Force Transducers Components"", evolving from the classical force transducer to the digital / intelligent one, with the inco

  12. Does Bohm's Quantum Force Have a Classical Origin?

    OpenAIRE

    Lush, David C.

    2014-01-01

    In the de Broglie - Bohm formulation of quantum mechanics, the electron is stationary in the ground state of hydrogenic atoms, because the quantum force exactly cancels the Coulomb attraction of the electron to the nucleus. In this paper it is shown that classical electrodynamics similarly predicts the Coulomb force can be effectively canceled by part of the magnetic force that occurs between two similar particles each consisting of a point charge moving with circulatory mot...

  13. Ground state energy fluctuations in the nuclear shell model

    International Nuclear Information System (INIS)

    Statistical fluctuations of the nuclear ground state energies are estimated using shell model calculations in which particles in the valence shells interact through well-defined forces, and are coupled to an upper shell governed by random 2-body interactions. Induced ground-state energy fluctuations are found to be one order of magnitude smaller than those previously associated with chaotic components, in close agreement with independent perturbative estimates based on the spreading widths of excited states

  14. Reduction of lateral loads in abutments using ground anchors

    OpenAIRE

    Laefer, Debra F.; Truong-hong, Linh; Le, Khanh Ba

    2013-01-01

    In bridge design, economically addressing large, lateral earth pressures on bridge abutments is a major challenge. Traditional approaches employ enlargement of the abutment components to resist these pressures. This approach results in higher construction costs. As an alternative, a formal approach using ground anchors to resist lateral soil pressure on bridge abutments is proposed herein. The ground anchors are designed to minimise lateral forces at the pile cap base. Design examples for hig...

  15. Ground State Entanglement Energetics

    OpenAIRE

    Buttiker, Markus; Jordan, Andrew N.

    2005-01-01

    We consider the ground state of simple quantum systems coupled to an environment. In general the system is entangled with its environment. As a consequence, even at zero temperature, the energy of the system is not sharp: a projective measurement can find the system in an excited state. We show that energy fluctuation measurements at zero temperature provide entanglement information. For two-state systems which exhibit a persistent current in the ground state, energy fluctua...

  16. Allergic reactions

    Science.gov (United States)

    ... that don't bother most people (such as venom from bee stings and certain foods, medications, and pollens) can ... it. If the allergic reaction is from a bee sting, scrape the ... release more venom. If the person develops an itchy rash, apply ...

  17. Neutrino reactions

    International Nuclear Information System (INIS)

    The CERN-JINR School of Physics is meant to give young experimental physicists an introduction to the theoretical aspects of recent advances in elementary particle physics. In this paper neutrino reactions are reviewed from a theoretical point of view. (Auth.)

  18. Ground Enterprise Management System Project

    National Aeronautics and Space Administration — Emergent Space Technologies Inc. proposes to develop the Ground Enterprise Management System (GEMS) for spacecraft ground systems. GEMS will provide situational...

  19. Systematic errors in ground heat flux estimation and their correction

    OpenAIRE

    Gentine, P.; Entekhabi, D; Heusinkveld, B.G.

    2012-01-01

    Incoming radiation forcing at the land surface is partitioned among the components of the surface energy balance in varying proportions depending on the time scale of the forcing. Based on a land-atmosphere analytic continuum model, a numerical land-surface model and field observations we show that high-frequency fluctuations in incoming radiation (with period less than 6 hours, for example due to intermittent clouds) are preferentially partitioned towards ground heat flux. These higher frequ...

  20. Investigating Forces and Motion

    CERN Document Server

    Weir, Jane

    2007-01-01

    Forces can't be seen, but without them, nothing around us would happen! A force is a push or pull that usually causes movement. Friction is a force that opposes motion and slows things down or stops them. Famous scientist and mathematician Sir Isaac Newton wrote the rules about forces and motion.

  1. Experimental study on effects of hardness of supporting ground

    International Nuclear Information System (INIS)

    The effects on the hardness and stratification of supporting ground on the vibration characteristics of a soil-structure system, were investigated using results of forced vibration tests conducted on large-scale models, constructed in the field. The following conclusions were drawn: From the results of the tests, the effect of radiation damping on the soft ground is greater than that on the hard ground except for the rotational component at higher frequencies. The soil impedances fluctuate due to stratification of the supporting ground. From the analytical studies, the soil impedances, the response of the structure and the characteristics of response of the surrounding ground can be evaluated by using the Axisymmetric Finite Element Method. (author)

  2. Enantioselective catalysis of photochemical reactions.

    Science.gov (United States)

    Brimioulle, Richard; Lenhart, Dominik; Maturi, Mark M; Bach, Thorsten

    2015-03-23

    The nature of the excited state renders the development of chiral catalysts for enantioselective photochemical reactions a considerable challenge. The absorption of a 400?nm photon corresponds to an energy uptake of approximately 300?kJ?mol(-1) . Given the large distance to the ground state, innovative concepts are required to open reaction pathways that selectively lead to a single enantiomer of the desired product. This Review outlines the two major concepts of homogenously catalyzed enantioselective processes. The first part deals with chiral photocatalysts, which intervene in the photochemical key step and induce an asymmetric induction in this step. In the second part, reactions are presented in which the photochemical excitation is mediated by an achiral photocatalyst and the transfer of chirality is ensured by a second chiral catalyst (dual catalysis). PMID:25728854

  3. Macroscopic QED in linearly responding media and a Lorentz-Force approach to dispersion forces

    International Nuclear Information System (INIS)

    In this thesis, a very general quantization scheme for the macroscopic electromagnetic field in arbitrary linearly responding media is presented. It offers a unified approach to QED in such media. Applying the quantization scheme, a theory of the dispersion forces on the basis of the Lorentz force is developed. By regarding the dispersion force as the (ground-state or thermal-state) expectation value of the Lorentz force that acts on appropriately defined charge and current densities, Casimir, Casimir-Polder, and van der Waals forces are united in a very natural way that makes transparent their common physical basis. Application of the theory to planar structures yields generalizations of well-known Lifschitz and Casimir-type formulas. (orig.)

  4. Macroscopic QED in linearly responding media and a Lorentz-Force approach to dispersion forces

    Energy Technology Data Exchange (ETDEWEB)

    Raabe, Christian

    2008-07-08

    In this thesis, a very general quantization scheme for the macroscopic electromagnetic field in arbitrary linearly responding media is presented. It offers a unified approach to QED in such media. Applying the quantization scheme, a theory of the dispersion forces on the basis of the Lorentz force is developed. By regarding the dispersion force as the (ground-state or thermal-state) expectation value of the Lorentz force that acts on appropriately defined charge and current densities, Casimir, Casimir-Polder, and van der Waals forces are united in a very natural way that makes transparent their common physical basis. Application of the theory to planar structures yields generalizations of well-known Lifschitz and Casimir-type formulas. (orig.)

  5. Ground motion predictions

    International Nuclear Information System (INIS)

    Nuclear generated ground motion is defined and then related to the physical parameters that cause it. Techniques employed for prediction of ground motion peak amplitude, frequency spectra and response spectra are explored, with initial emphasis on the analysis of data collected at the Nevada Test Site (NTS). NTS postshot measurements are compared with pre-shot predictions. Applicability of these techniques to new areas, for example, Plowshare sites, must be questioned. Fortunately, the Atomic Energy Commission is sponsoring complementary studies to improve prediction capabilities primarily in new locations outside the NTS region. Some of these are discussed in the light of anomalous seismic behavior, and comparisons are given showing theoretical versus experimental results. In conclusion, current ground motion prediction techniques are applied to events off the NTS. Predictions are compared with measurements for the event Faultless and for the Plowshare events, Gasbuggy, Cabriolet, and Buggy I. (author)

  6. Anti-gravity treadmills are effective in reducing knee forces.

    Science.gov (United States)

    Patil, Shantanu; Steklov, Nikolai; Bugbee, William D; Goldberg, Timothy; Colwell, Clifford W; D'Lima, Darryl D

    2013-05-01

    Lower body positive pressure (LBPP) treadmills permit significant unweighting of patients and have the potential to enhance recovery following lower limb surgery. We determined the efficacy of an LBPP treadmill in reducing knee forces in vivo. Subjects, implanted with custom electronic tibial prostheses to measure forces in the knee, were tested on a treadmill housed within a LBPP chamber. Tibiofemoral forces were monitored at treadmill speeds from 1.5?mph (0.67?m/s) to 4.5?mph (2.01?m/s), treadmill incline from -10° to +10°, and four treadmill chamber pressure settings adjusted to decrease net treadmill reaction force from 100% to 25% of the subject's body weight (BW). The peak axial tibiofemoral force ranged from 5.1 times BW at a treadmill speed of 4.5?mph (2.01?m/s) and a pressure setting of 100% BW to 0.8 times BW at 1.5?mph (0.67?m/s) and a pressure setting of 25% BW. Peak knee forces were significantly correlated with walking speed and treadmill reaction force (R(2) ?=?0.77, p?=?0.04). The LBPP treadmill might be an effective tool in the rehabilitation of patients following lower-extremity surgery. The strong correlation between tibiofemoral force and walking speed and treadmill reaction forces allows for more precisely achieving the target knee forces desired during early rehabilitation. PMID:23239580

  7. Neutrino nuclear response and photo nuclear reaction

    CERN Document Server

    Ejiri, H; Boswell, M; Young, A

    2013-01-01

    Photo nuclear reactions are shown to be used for studying neutrino/weak nuclear responses involved in astro-neutrino nuclear interactions and double beta decays. Charged current weak responses for ground and excited states are studied by using photo nuclear reactions through isobaric analog states of those states, while neutral current weak responses for excited states are studied by using photo nuclear reactions through the excited states. The weak interaction strengths are studied by measuring the cross sections of the photo nuclear reactions, and the spin and parity of the state are studied by measuring angular correlations of particles emitted from the photo nuclear reactions. Medium-energy polarized photons obtained from laser photons scattered off GeV electrons are very useful. Nuclear responses studied by photo nuclear reactions are used to evaluate neutrino/weak nuclear responses, i.e. nuclear beta and double beta matrix elements and neutrino nuclear interactions, and to verify theoretical calculation...

  8. Neutrino-nuclear response and photonuclear reactions

    Science.gov (United States)

    Ejiri, H.; Titov, A. I.; Boswell, M.; Young, A.

    2013-11-01

    Photonuclear reactions are shown to be used for studying neutrino (weak) nuclear responses involved in astroneutrino nuclear interactions and double beta decays. Charged current weak responses for ground and excited states are studied by using photonuclear reactions through isobaric analog states of those states, while neutral current weak responses for excited states are studied by using photonuclear reactions through the excited states. The weak interaction strengths are studied by measuring the cross sections of the photonuclear reactions, and the spin and parity of the states are studied by measuring angular correlations of particles emitted from the photonuclear reactions. Medium-energy polarized photons obtained from laser photons scattered off GeV electrons are very useful. Nuclear responses studied by photonuclear reactions are used to evaluate neutrino (weak) nuclear responses, i.e., nuclear beta and double beta matrix elements and neutrino-nuclear interactions, and to verify theoretical calculations for them.

  9. Coding Issues in Grounded Theory

    Science.gov (United States)

    Moghaddam, Alireza

    2006-01-01

    This paper discusses grounded theory as one of the qualitative research designs. It describes how grounded theory generates from data. Three phases of grounded theory--open coding, axial coding, and selective coding--are discussed, along with some of the issues which are the source of debate among grounded theorists, especially between its…

  10. A Study of Winglet and Aerodynamic Interferences in 3-D Viscous Flow around a Flying-Boat in Ground Effect

    Directory of Open Access Journals (Sweden)

    H. Afshar

    2009-01-01

    Full Text Available In this study, the flow field about a complete flying-boat in ground effect is resolved. The influences of using winglet in ground and out of ground effects are compared and it is shown that ground affects this influence to a large extent. It is also shown that with careful shaping of the body and using a step underneath the body a propulsive force can be produced in vicinity of the ground. However, this causes an increase in drag force in free flight.

  11. Dynamic reaction path analysis based on an intrinsic reaction coordinate

    Science.gov (United States)

    Taketsugu, Tetsuya; Gordon, Mark S.

    1995-12-01

    We propose two methods that may be used to describe the dynamic reaction path (DRP) based on an intrinsic reaction coordinate (IRC) or minimum energy path, to examine how the actual dynamics proceeds relative to the IRC path. In the first of these, any point on the DRP is expressed in terms of the IRC and the distance from the IRC path. In the second method, any DRP point is expressed in terms of the IRC, the curvature coordinate, and the distance from a two-dimensional ``reaction plane'' determined by the IRC path tangent and curvature vectors. The latter representation is based on the fact that the 3N-8 dimensional space orthogonal to the reaction plane is independent of an internal centrifugal force caused by the motion along the IRC path. To analyze the relation between geometrical features of the IRC path and the dynamics, we introduce a function that estimates the variation of the reaction plane along the IRC path. As demonstrations, the methods are applied to the dissociation reaction of thiofolmaldehyde (H2CS?H2+CS).

  12. Sticking like sticky tape: tree frogs use friction forces to enhance attachment on overhanging surfaces

    Science.gov (United States)

    Endlein, Thomas; Ji, Aihong; Samuel, Diana; Yao, Ning; Wang, Zhongyuan; Barnes, W. Jon P.; Federle, Walter; Kappl, Michael; Dai, Zhendong

    2013-01-01

    To live and clamber about in an arboreal habitat, tree frogs have evolved adhesive pads on their toes. In addition, they often have long and slender legs to facilitate not only long jumps, but also to bridge gaps between leaves when climbing. Both adhesive pads and long limbs are used in conjunction, as we will show in this study. Previous research has shown that tree frogs change from a crouched posture (where the limbs are close to the body) to a sprawled posture with extended limbs when clinging on to steeper inclines such as vertical or overhanging slopes. We investigated this change in posture in White's tree frogs (Litoria caerulea) by challenging the frogs to cling onto a tiltable platform. The platform consisted of an array of 24 three-dimensional force transducers, which allowed us to measure the ground reaction forces of the frogs during a tilt. Starting from a crouched resting position, the normal forces on the forelimbs changed sign and became increasingly negative with increasing slope angle of the platform. At about 106°±12°, tilt of the platform the frogs reacted by extending one or two of their limbs outwards. At a steeper angle (131°±11°), the frogs spread out all their limbs sideways, with the hindlimbs stretched out to their maximum reach. Although the extension was strongest in the lateral direction, limbs were significantly extended in the fore–aft direction as well. With the extension of the limbs, the lateral forces increased relative to the normal forces. The large contribution of the in-plane forces helped to keep the angle between the force vector and the platform small. The Kendall theory for the peeling of adhesive tape predicts that smaller peel angles lead to higher attachment forces. We compare our data with the predictions of the Kendall model and discuss possible implications of the sliding of the pads on the surface. The forces were indeed much larger for smaller angles and thus can be explained by peeling theory. PMID:23325755

  13. Earth's Water:Ground Water

    Science.gov (United States)

    This USGS site contains graphs, tables, and charts for the following ground water topics: What is ground water, ground water flow diagrams, importance of groundwater, and trends in ground-water use. Ground water quality, pesticides, aquifers, waterwells, artesian wells, sinkholes, and land subsidence are also covered. There are a variety of links within all of the above topics and a very complete glossary, as well as numerous charts, maps, photographs and illustrations.

  14. Nuclear reactions. An introduction

    International Nuclear Information System (INIS)

    Modern, self-contained introduction to the subject matter. Emphasizes the interplay between theory and experiment. Course-tested tutorial style, contains many derivations. Nuclei and nuclear reactions offer a unique setting for investigating three (and in some cases even all four) of the fundamental forces in nature. Nuclei have been shown - mainly by performing scattering experiments with electrons, muons, and neutrinos - to be extended objects with complex internal structures: constituent quarks; gluons, whose exchange binds the quarks together; sea-quarks, the ubiquitous virtual quark-antiquark pairs and, last but not least, clouds of virtual mesons, surrounding an inner nuclear region, their exchange being the source of the nucleon-nucleon interaction. The interplay between the (mostly attractive) hadronic nucleon-nucleon interaction and the repulsive Coulomb force is responsible for the existence of nuclei; their degree of stability, expressed in the details and limits of the chart of nuclides; their rich structure and the variety of their interactions. Despite the impressive successes of the classical nuclear models and of ab-initio approaches, there is clearly no end in sight for either theoretical or experimental developments as shown e.g. by the recent need to introduce more sophisticated three-body interactions to account for an improved picture of nuclear structure and reactions. Yet, it turns out that the internal structure of the nucleons has comparatively little influence on the behavior of the nucleons in nuclei, and nuclear physics - especially nuclear structure and reactions - is thus a field of science in its own right, without much recourse to subnuclear degrees of freedom. This book collects essential material that was presented in the form of lectures notes in nuclear physics courses for graduate students at the University of Cologne. It follows the course's approach, conveying the subject matter by combining experimental facts and experimental methods and tools with basic theoretical knowledge. Emphasis is placed on the importance of spin and orbital angular momentum (leading e.g. to applications in energy research, such as fusion with polarized nuclei), and on the operational definition of observables in nuclear physics. The end-of-chapter problems serve above all to elucidate and detail physical ideas that could not be presented in full detail in the main text. Readers are assumed to have a working knowledge of quantum mechanics and a basic grasp of both non-relativistic and relativistic kinematics; the latter in particular is a prerequisite for interpreting nuclear reactions and the connections to particle and high-energy physics.

  15. FBM Ground Segment and Operations Concept

    Science.gov (United States)

    Cardoso, P.; Gonçalves, L.; Ambrósio, A.; Carvalho, H.

    The French-Brazilian Micro-satellite (FBM) Mission is a cooperative program between the French Space Agency ("Centre National d`Estudes Spatiales" - CNES - France) and the National Institute for Space Research (INPE - Brazil). This mission consists in developing, launching, and controlling a scientific/technologic micro-satellite as well as the payload data dissemination. Five Brazilian and four French technological and scientific experiments will fly onboard the FBM. The task division among INPE and CNES is as follows: INPE is responsible for the Satellite System, Power Supply, Structure and Thermal Control Subsystem, Ground Segment and Operations. CNES provides the AOCS, TT&C and OBDH Subsystems. This paper presents the Ground Segment architecture, and describes its development process, along with the Mission Operations Concept, adopted for the joint program. The Ground Segment is being developed under the directive of maximum re-use of existing systems in Brazil, and the constraints imposed by the Command &Control Interface Specifications; Ground to Board Interface Definition applicable to the subsystems provided by CNES. In addition, a maximum commonality between processes and elements of AIT and operations (Control Center/Ground Station) was sought for risk and costs reduction reasons. Mission Operations were conceived as a trade-off between operational autonomy of the satellite and ground segment, and a fast reaction under contingency situations foreseen for the scientific payload equipment. Scheduled to be launched by early 2004, FBM aims at being a valuable tool for both the French and Brazilian scientific and technological communities, and provides a rich framework of technical cooperation between both countries.

  16. Spallation reactions

    International Nuclear Information System (INIS)

    Spallation reactions dominate the interactions of hadrons with nuclei in the GeV range (from ? 0.1 to ? 10 GeV). They correspond to a sometimes important ejection of light particles leaving most of the time a residue of mass commensurate with the target mass. The main features of the experimental data are briefly reviewed. The most successful theoretical model, namely the intranuclear cascade + evaporation model, is presented. Its physical content, results and possible improvements are critically discussed. Alternative approaches are shortly reviewed. (author)

  17. Collison and Grounding

    DEFF Research Database (Denmark)

    Wang, G. unknown

    2006-01-01

    COMMITTEE MANDATE Concern for structural arrangements on ships and floating structures with regard to their integrity and adequacy in the events of collision and grounding, with the view towards risk assessment and management. Consideration shall be given to the frequency of occurrence, the probabilistic and physical nature of such accidents, and consequences on watertight integrity, structural integrity and environment.

  18. Ground-water Aquifers

    Science.gov (United States)

    This description of a ground-water aquifer has a graphic representation to accompany it. It is part of the U.S. Geologic Survey's Water Science for Schools website. Links to other parts of the site, such as definitions and types of wells, are included.

  19. Ground Water Atlas

    Science.gov (United States)

    Authored by the United States Geological Survey, the series consists of thirteen chapters which describes the ground-water resources of regional areas that collectively cover the 50 States, Puerto Rico, and the U.S. Virgin Islands. This is a nice reference tool for those interested in geology.

  20. Ground movements associated with gas hydrate production

    International Nuclear Information System (INIS)

    This report deals with a study directed towards a modeling effort on production related ground movements and subsidence resulting from hydrate dissociation. The goal of this research study was to evaluate whether there could be subsidence related problems that could be an impediment to hydrate production. During the production of gas from a hydrate reservoir, it is expected that porous reservoir matrix becomes more compressible which may cause reservoir compression (compaction) under the influence of overburden weight. The overburden deformations can propagate its influence upwards causing subsidence near the surface where production equipment will be located. In the present study, the reservoir compaction is modeled by using the conventional ''stress equilibrium'' approach. In this approach, the overburden strata move under the influence of body force (i.e. self weight) in response to the ''cavity'' generated by reservoir depletion. The present study is expected to provide a ''lower bound'' solution to the subsidence caused by hydrate reservoir depletion. The reservoir compaction anticipated during hydrate production was modeled by using the finite element method, which is a powerful computer modeling technique. The ground movements at the reservoir roof (i.e. reservoir compression) cause additional stresses and disturbance in the overburden strata. In this study, the reservoir compaction was modeled by using the conventional ''stress equilibrium'' approach. In this approach, the overburden strata move under the influence of body force (i.e. self weight) in response to the ''cavity'' generated by reservoir depletion. The resulting stresses and ground movements were computed by using the finite element method. Based on the parameters used in this investigation, the maximum ground subsidence could vary anywhere from 0.50 to 6.50 inches depending on the overburden depth and the size of the depleted hydrate reservoir

  1. Aerodynamic ground effect in fruitfly sized insect takeoff

    CERN Document Server

    Kolomenskiy, Dmitry; Engels, Thomas; Liu, Hao; Schneider, Kai; Nave, Jean-Christophe

    2015-01-01

    Flapping-wing takeoff is studied using numerical modelling, considering the voluntary takeoff of a fruitfly as reference. The parameters of the model are then varied to explore the possible effects of interaction between the flapping-wing model and the ground plane. The numerical method is based on a three-dimensional Navier-Stokes solver and a simple flight dynamics solver that accounts for the body weight, inertia, and the leg thrust. Forces, power and displacements are compared for takeoffs with and without ground effect. Natural voluntary takeoff of a fruitfly, modified takeoffs and hovering are analyzed. The results show that the ground effect during the natural voluntary takeoff is negligible. In the modified takeoffs, the ground effect does not produce any significant increase of the vertical force neither. Moreover, the vertical force even drops in most of the cases considered. There is a consistent increase of the horizontal force, and a decrease of the aerodynamic power, if the rate of climb is suff...

  2. Calculation of ground vibration spectra from heavy military vehicles

    Science.gov (United States)

    Krylov, V. V.; Pickup, S.; McNuff, J.

    2010-07-01

    The demand for reliable autonomous systems capable to detect and identify heavy military vehicles becomes an important issue for UN peacekeeping forces in the current delicate political climate. A promising method of detection and identification is the one using the information extracted from ground vibration spectra generated by heavy military vehicles, often termed as their seismic signatures. This paper presents the results of the theoretical investigation of ground vibration spectra generated by heavy military vehicles, such as tanks and armed personnel carriers. A simple quarter car model is considered to identify the resulting dynamic forces applied from a vehicle to the ground. Then the obtained analytical expressions for vehicle dynamic forces are used for calculations of generated ground vibrations, predominantly Rayleigh surface waves, using Green's function method. A comparison of the obtained theoretical results with the published experimental data shows that analytical techniques based on the simplified quarter car vehicle model are capable of producing ground vibration spectra of heavy military vehicles that reproduce basic properties of experimental spectra.

  3. A comparison of methods for determining the rate of force development during isometric midthigh clean pulls.

    Science.gov (United States)

    Haff, G Gregory; Ruben, Ryan P; Lider, Joshua; Twine, Corey; Cormie, Prue

    2015-02-01

    Twelve female division I collegiate volleyball players were recruited to examine the reliability of several methods for calculating the rate of force development (RFD) during the isometric midthigh clean pull. All subjects were familiarized with the isometric midthigh clean pull and participated in regular strength training. Two isometric midthigh clean pulls were performed with 2 minutes rest between each trail. All measures were performed in a custom isometric testing device that included a step-wise adjustable bar and a force plate for measuring ground reaction forces. The RFD during predetermined time zone bands (0-30, 0-50, 0-90, 0-100, 0-150, 0-200, and 0-250 milliseconds) was then calculated by dividing the force at the end of the band by the band's time interval. The peak RFD was then calculated with the use of 2, 5, 10, 20, 30, and 50 milliseconds sampling windows. The average RFD (avgRFD) was calculated by dividing the peak force (PF) by the time to achieve PF. All data were analyzed with the use of intraclass correlation alpha (ICC?) and the coefficient of variation (CV) and 90% confidence intervals. All predetermined RFD time bands were deemed reliable based on an ICC? >0.95 and a CV <4%. Conversely, the avgRFD failed to meet the reliability standards set for this study. Overall, the method used to assess the RFD during an isometric midthigh clean pull impacts the reliability of the measure and predetermined RFD time bands should be used to quantify the RFD. PMID:25259470

  4. Nuclear reactions

    International Nuclear Information System (INIS)

    Nuclear reactions' marks a new development in the study of television as an agency of public policy debate. During the Eighties, nuclear energy became a major international issue. The disasters at Three-mile Island and Chernobyl created a global anxiety about its risks and a new sensitivity to it among politicians and journalists. This book is a case-study into documentary depictions of nuclear energy in television and video programmes and into the interpretations and responses of viewers drawn from many different occupational groupings. How are the complex and specialist arguments about benefit, risk and proof conveyed through the different conventions of commentary, interview and film sequence? What symbolic associations does the visual language of television bring to portrayals of the issue? And how do viewers make sense of various and conflicting accounts, connecting what they see and hear on the screen with their pre-existing knowledge, experience and 'civic' expectations. The authors examine some of the contrasting forms and themes which have been used by programme makers to explain and persuade, and then give a sustained analysis of the nature and sources of viewers' own accounts. 'Nuclear Reactions' inquires into the public meanings surrounding energy and the environment, spelling out in its conclusion some of the implications for future media treatments of this issue. It is also a key contribution to the international literature on 'television knowledge' and literature on 'television knowledge' and the processes of active viewing. (author)

  5. Radiation reaction in various dimensions

    CERN Document Server

    Galtsov, D V

    2002-01-01

    We discuss the radiation reaction problem for an electric charge moving in flat space-time of arbitrary dimensions. It is shown that four is the unique dimension where a local differential equation exists accounting for the radiation reaction and admitting a consistent mass-renormalization (the Dirac-Lorentz equation). In odd dimensions the Huygens principle does not hold; as a result, the radiation reaction force depends on the whole past history of a charge (radiative tail). We show that the divergence in the tail integral can be removed by the mass renormalization only in the 2+1 theory. In even dimensions higher than four, divergences can not be removed by a renormalization.

  6. First observation of $^{13}$Li ground state

    CERN Document Server

    Kohley, Z; DeYoung, P A; Volya, A; Baumann, T; Bazin, D; Christian, G; Cooper, N L; Frank, N; Gade, A; Hall, C; Hinnefeld, J; Luther, B; Mosby, S; Peters, W A; Smith, J K; Snyder, J; Spyrou, A; Thoennessen, M

    2013-01-01

    The ground state of neutron-rich unbound $^{13}$Li was observed for the first time in a one-proton removal reaction from $^{14}$Be at a beam energy of 53.6 MeV/u. The $^{13}$Li ground state was reconstructed from $^{11}$Li and two neutrons giving a resonance energy of 120$^{+60}_{-80}$ keV. All events involving single and double neutron interactions in the Modular Neutron Array (MoNA) were analyzed, simulated, and fitted self-consistently. The three-body ($^{11}$Li+$n+n$) correlations within Jacobi coordinates showed strong dineutron characteristics. The decay energy spectrum of the intermediate $^{12}$Li system ($^{11}$Li+$n$) was described with an s-wave scattering length of greater than -4 fm, which is a smaller absolute value than reported in a previous measurement.

  7. Contribution to the models for calculation and analysis of grounding grids and grounding systems

    International Nuclear Information System (INIS)

    The aim of this dissertation is improving the existing models and finding new for calculating the conditions in the complex grounding systems and analyzing their performances. For that purpose, firstly, a model network of the grounding system is created, and the ways of modelling the separate elements are studied and elaborated also. Some methods for solving groundings with arbitrary complexity and dimensions are studied and worked out too. Afterwards the TL in models are worked out, with or without protective rope. Appropriate models are detail worked out and formed for the energetic cables, both for isolated and distributive outer shield - type PP, XHP, XHE, IPO, and IPZO. At the same time, the eventual presence of additional groundings like steel tapes and cooper ropes placed into the cable trench together with the cable is considered. Particular attention is dedicated on the cables with steel reinforcement, whose parameters of the 'unit length depends of the current in the shield and in the reinforcement, because they are sources of nonlinearity and also of the problems connected with its modelling and solving. Therefore an approach is made to the modelling of the mutual conductive couplings between the elements of the grounding system (ex. between two and more cables, the parts of one cable, the groundings of one substation and the cables in theirs immediate nearness and so on.). The electromagnetic couplings existing between the phases conductors, under the inflween the phases conductors, under the influence of the fault, like, (protective rope (TL), the metal shields, and the cables with electric protection, are included too. The mutual couplings are estimated over introducing inducted electro motor forces (EMF) in the transversal and/or longitudinal branches of the elements of the grounding system. (depending on what kind of coupling we are talking-conductive or inductive). These inductive EMF later are transformed into equivalent current generators and in that way the system will be harnessed. The number of the current generators that appear in the cycle with the procedure 'replacing of the current generators' are transferred easily into the node of the network where the fault is made previously. Further on, some modem numerical methods and procedures for calculating the grounding system, convenient for the use of the personal computers are studied. Some modem numerical procedures are adopted and worked out for calculating networks (cycles) with radial structure and/or with small number of loops. They are used for solving the condition in the network part of the grounding system, which means that up to now the researches are pointing to the adequacy of the use of the methods for summarizing admittances and summarizing current (MSAC). The next step, after the distribution of the whole system is defined, is passing to the estimation of the safety conditions from high touch and step voltages in the environment of the different groundings. For that purpose, the characteristics of the biggest number of typical groundings of the MV/LV substations, the characteristics of some kind's network groundings of the HV/N4V substation are studied. The tower TL groundings (ring shaped, square shaped, ray shaped) are analyzed in details. At the same time, a data multitude is calculated, necessary for the further analysis, and consisting theirs resistances to ground.(for a given value of a specific resistance of the soil), the maximum and the average values of touch and step potentials, as well as the frequencies of their appearances,. (frequent histograms FH) of the touch and step potential differences) and so on. All these quantities are depending on the geometry of the grounding. The calculating FH of different kinds of groundings is performed with a computer simulation-'simulation Monte Carlo'. In order to obtain them, an appropriate software is produced, which by making the number of experiments (simulations), defines the needed performances of the grounding statistically, and at the same time, accidentally generates the posi

  8. Forces in general relativity

    International Nuclear Information System (INIS)

    Many textbooks dealing with general relativity do not demonstrate the derivation of forces in enough detail. The analyses presented herein demonstrate straightforward methods for computing forces by way of general relativity. Covariant divergence of the stress-energy-momentum tensor is used to derive a general expression of the force experienced by an observer in general coordinates. The general force is then applied to the local co-moving coordinate system of a uniformly accelerating observer, leading to an expression of the inertial force experienced by the observer. Next, applying the general force in Schwarzschild coordinates is shown to lead to familiar expressions of the gravitational force. As a more complex demonstration, the general force is applied to an observer in Boyer-Lindquist coordinates near a rotating, Kerr black hole. It is then shown that when the angular momentum of the black hole goes to zero, the force on the observer reduces to the force on an observer held stationary in Schwarzschild coordinates. As a final consideration, the force on an observer moving in rotating coordinates is derived. Expressing the force in terms of Christoffel symbols in rotating coordinates leads to familiar expressions of the centrifugal and Coriolis forces on the observer. It is envisioned that the techniques presented herein will be most useful to graduate level students, as well as those undergraduate students having experience with general relativity and tensor anance with general relativity and tensor analysis.

  9. Forces in general relativity

    Science.gov (United States)

    Ridgely, Charles T.

    2010-07-01

    Many textbooks dealing with general relativity do not demonstrate the derivation of forces in enough detail. The analyses presented herein demonstrate straightforward methods for computing forces by way of general relativity. Covariant divergence of the stress-energy-momentum tensor is used to derive a general expression of the force experienced by an observer in general coordinates. The general force is then applied to the local co-moving coordinate system of a uniformly accelerating observer, leading to an expression of the inertial force experienced by the observer. Next, applying the general force in Schwarzschild coordinates is shown to lead to familiar expressions of the gravitational force. As a more complex demonstration, the general force is applied to an observer in Boyer-Lindquist coordinates near a rotating, Kerr black hole. It is then shown that when the angular momentum of the black hole goes to zero, the force on the observer reduces to the force on an observer held stationary in Schwarzschild coordinates. As a final consideration, the force on an observer moving in rotating coordinates is derived. Expressing the force in terms of Christoffel symbols in rotating coordinates leads to familiar expressions of the centrifugal and Coriolis forces on the observer. It is envisioned that the techniques presented herein will be most useful to graduate level students, as well as those undergraduate students having experience with general relativity and tensor analysis.

  10. Severe cutaneous reaction to CS gas.

    Science.gov (United States)

    Varma, S; Holt, P J

    2001-05-01

    Tear gas is used throughout the World for control of riots and civil disobedience. CS gas as used by the UK police force is issued as a 'spray' and is 5% CS in methylisobutylketone (MIBK), a potent irritant. Assaults on police officers in forces issued with CS spray have fallen significantly over the past 3 years, whilst having risen in areas without it. Thus, CS gas appears to be an effective deterrent. However, significant cutaneous reactions can occur as a result of exposure. We report a severe contact dermatitis to CS gas to highlight the clinical features. The nature of CS gas and potential cutaneous adverse reactions are discussed. PMID:11422166

  11. The Future of Grounded Theory

    OpenAIRE

    Barney G Glaser, Ph D.

    2010-01-01

    I would like to speak about what I consider the future of grounded theory. I will discuss in whose hands the future of grounded theory appears to be and what accounts for its spread, its use and misuse, and where the majority of grounded theory studies are occurring. I will then briefly review poor grounded theory, qualitative grounded theory, social fictions, and theory bits. Finally, I will touch on the future structures in which grounded theory will be taught and centered.First, a few guid...

  12. Relativistic Linear Restoring Force

    OpenAIRE

    CLARK, D; Franklin, J; Mann, N

    2012-01-01

    We consider two different forms for a relativistic version of a linear restoring force. The pair comes from taking Hooke's law to be the force appearing on the right of the relativistic expressions: dp/dt or dp/dtau . Either formulation recovers Hooke's law in the non-relativistic limit. In addition to these two forces, we introduce a form of retardation appropriate for the description of a linear (in displacement) force arising from the interaction of a pair of particles wi...

  13. Trois familles, quatre forces

    CERN Multimedia

    Augereau, J F

    2002-01-01

    ENSEMBLE DE QUATRE ARTICLES - LARGE HADRON COLLIDER: Le monde des particules tel que nous le connaissons aujourd'hui est constitue de trois familles de quatre membres. Ces particules sont collees les unes aux autres par des forces. Celles-ci, au nombre de quatre - gravitation, force forte, force electromagnetique et force faible -, sont " portees " par d'autres particules dont certaines sont a decouvrir (graviton) et d'autres deja identifiees (gluons, photons, bosons W et Z) (1/2 page).

  14. Ground response curves for rock excavations supported by ungrouted tensioned rockbolts

    Science.gov (United States)

    Labiouse, V.

    1996-01-01

    A numerical analysis has been developed for the design of ungrouted tensioned rockbolts as support of excavations under axisymmetric conditions. The bolts dimensions (length, crosssection, longitudinal and circumferential spacings), their stiffness, their pre-tension load and the delay of installation are taken into account. Moreover, the method effects three main improvements in the usual theory, taking into consideration: 1. the reaction force transferred to the rock mass in the bolts anchoring zone, 2. the elastic recompression of the carrying ring surrounding the excavation due to the bolts preload, and 3. the relative displacement of the bolts ends which has a repercussion on their tension. Since the usual rock-support interaction analysis is only available when the rock mass and the support behave independently, an alternative solution has been explored for the bolting system (since it cannot be considered as an internal support). It consists to include the effect of the rockbolts into the ground reaction curve. In this paper, the principles of the analysis are explained and a numerical application is taken.

  15. Crossflow force transducer

    International Nuclear Information System (INIS)

    A force transducer for measuring lift and drag coefficients for a circular cylinder in turbulent water flow is presented. In addition to describing the actual design and construction of the strain-gauged force- ring based transducer, requirements for obtained valid fluid force test data are discussed, and pertinent flow test experience is related

  16. Debunking Coriolis Force Myths

    Science.gov (United States)

    Shakur, Asif

    2014-01-01

    Much has been written and debated about the Coriolis force. Unfortunately, this has done little to demystify the paradoxes surrounding this fictitious force invoked by an observer in a rotating frame of reference. It is the purpose of this article to make another valiant attempt to slay the dragon of the Coriolis force! This will be done without…

  17. Crossflow force transducer. [LMFBR

    Energy Technology Data Exchange (ETDEWEB)

    Mulcahy, T M

    1982-05-01

    A force transducer for measuring lift and drag coefficients for a circular cylinder in turbulent water flow is presented. In addition to describing the actual design and construction of the strain-gauged force- ring based transducer, requirements for obtained valid fluid force test data are discussed, and pertinent flow test experience is related.

  18. Forces in General Relativity

    Science.gov (United States)

    Ridgely, Charles T.

    2010-01-01

    Many textbooks dealing with general relativity do not demonstrate the derivation of forces in enough detail. The analyses presented herein demonstrate straightforward methods for computing forces by way of general relativity. Covariant divergence of the stress-energy-momentum tensor is used to derive a general expression of the force experienced…

  19. Ground Truthing your Image

    Science.gov (United States)

    In this investigation students explore how resolution affects information content on remotely sensed images, relate remote sensor resolution (pixel size) to information content, and gain an understanding of the information content of different kinds of remote sensing imagery. Students examine aerial or satellite images of the area around their school,interpret remotely sense images, and verify them using ground trotting techniques. Magnifying glasses (2x, 5x and 10x power), aerial photographs, plant identification manual, and a tape measure are needed supplies. This exercise is part of the Ground Truth Studies Teacher Handbook (GTSTH), and is a follow-up investigation to the Digital Faces activity of the same resource. GTSTH provides more than 20 activities to build student understanding of global change and remote sensing, and includes background chapters for teachers, glossary, and appendices.

  20. Ibis ground calibration

    International Nuclear Information System (INIS)

    We present an overview of results obtained from IBIS ground calibrations. The spectral and spatial characteristics of the detector planes and surrounding passive materials have been determined through a series of calibration campaigns. Measurements of pixel gain, energy resolution, detection uniformity, efficiency and imaging capability are presented. The key results obtained from the ground calibration have been: - optimization of the instrument tunable parameters, - determination of energy linearity for all detection modes, - determination of energy resolution as a function of energy through the range 20 keV - 3 MeV, - demonstration of imaging capability in each mode, - measurement of intrinsic detector non-uniformity and understanding of the effects of passive materials surrounding the detector plane, and - discovery (and closure) of various leakage paths through the passive shielding system

  1. Ground motion effects

    International Nuclear Information System (INIS)

    Ground motion caused by natural earthquakes or by nuclear explosion causes buildings and other structures to respond in such manner as possibly to have high unit stresses and to be subject to damage or-in some cases-collapse. Even minor damage may constitute a hazard to persons within or adjacent to buildings. The risk of damage may well be the governing restraint on the uses of nuclear energy for peaceful purposes. Theory is advanced regarding structural-dynamic response but real buildings and structures are complex, highly variable, and often difficult to model realistically. This paper discusses the state of knowledge, the art of damage prediction and safety precautions, and shows ground motion effects from explosions of underground nuclear devices in the continental United States including events Salmon, Gasbuggy, Boxcar, Faultless and Benham. (author)

  2. Applying Grounded Theory

    OpenAIRE

    Barney G Glaser, Phd

    2014-01-01

    Application of grounded theory (GT) is a relatively neglected topic by my colleagues. I have written several chapters in my books on applying GT. Two colleagues, Odis Simmons and Barbara Artinian (2009), as well as Dirks and Mills (2011), and Walsh (2014), have also written about applying GT. In the first two chapters of this book I discuss at length properties of generally applying GT and then professional issues and personal matters when applying of GT. There follows in this book nine chapt...

  3. Remodeling Grounded Theory

    Directory of Open Access Journals (Sweden)

    Barney G. Glaser Ph.D., Hon. Ph.D.

    2004-11-01

    Full Text Available This paper outlines my concerns with Qualitative Data Analysis’ (QDAnumerous remodelings of Grounded Theory (GT and the subsequent eroding impact. I cite several examples of the erosion and summarize essential elements of classic GT methodology. It is hoped that the article will clarify my concerns with the continuing enthusiasm but misunderstood embrace of GT by QDA methodologists and serve as a preliminary guide to novice researchers who wish to explore the fundamental principles of GT.

  4. The LOFT Ground Segment

    DEFF Research Database (Denmark)

    Bozzo, E.; Antonelli, A.

    2014-01-01

    LOFT, the Large Observatory For X-ray Timing, was one of the ESA M3 mission candidates that completed their assessment phase at the end of 2013. LOFT is equipped with two instruments, the Large Area Detector (LAD) and the Wide Field Monitor (WFM). The LAD performs pointed observations of several targets per orbit (~90 minutes), providing roughly ~80 GB of proprietary data per day (the proprietary period will be 12 months). The WFM continuously monitors about 1/3 of the sky at a time and provides data for about ~100 sources a day, resulting in a total of ~20 GB of additional telemetry. The LOFT Burst alert System additionally identifies on-board bright impulsive events (e.g., Gamma-ray Bursts, GRBs) and broadcasts the corresponding position and trigger time to the ground using a dedicated system of ~15 VHF receivers. All WFM data are planned to be made public immediately. In this contribution we summarize the planned organization of the LOFT ground segment (GS), as established in the mission Yellow Book 1 . Wedescribe the expected GS contributions from ESA and the LOFT consortium. A review is provided of the planned LOFT data products and the details of the data flow, archiving and distribution. Despite LOFT was not selected for launch within the M3 call, its long assessment phase (> 2 years) led to a very solid mission design and an efficient planning of its ground operations.

  5. Grounded spatial belief revision.

    Science.gov (United States)

    Nejasmic, Jelica; Bucher, Leandra; Knauff, Markus

    2015-05-01

    Beliefs frequently undergo revisions, especially when new pieces of information are true but inconsistent with current beliefs. In previous studies, we showed that linguistic asymmetries provided by relational statements, play a crucial role in spatial belief revision. Located objects (LO) are preferably revised compared to reference objects (RO), known as the LO-principle. Here we establish a connection between spatial belief revision and grounded cognition. In three experiments, we explored whether imagined physical object properties influence which object is relocated and which remains at its initial position. Participants mentally revised beliefs about the arrangements of objects which could be envisaged as light and heavy (Experiment 1), small and large (Experiment 2), or movable and immovable (Experiment 3). The results show that intrinsic object properties are differently taken into account during spatial belief revision. Object weight did not alter the LO-principle (Experiment 1), whereas object size was found to influence which object was preferably relocated (Experiment 2). Object movability did not affect relocation preferences but had an effect on relocation durations (Experiment 3). The findings support the simulation hypothesis within the grounded cognition approach and create new connections between the spatial mental model theory of reasoning and the idea of grounded cognition. PMID:25796056

  6. As forças transientes durante a marcha militar / Transient forces during military marching / Las fuerzas con efecto transiente durante la marcha militar

    Scientific Electronic Library Online (English)

    Thais Pereira, Guisande; Julio Cerca, Amadio; Alberto Carlos, Amadio; Luis, Mochizuki.

    2013-12-01

    Full Text Available INTRODUÇÃO: O padrão vertical anormal da força de reação do solo (FRS) apresenta a assimetria ou mais de dois picos como marcha patológica típica. Uma força típica e assimétrica é a força transiente. Será que a marcha militar é uma espécie de marcha patológica? OBJETIVO: Descrever e analisar a força [...] de reação do solo vertical durante a fase de apoio da marcha militar. MÉTODO: Os participantes foram 20 soldados do Exército Brasileiro que tiveram anteriormente uma lesão nos membros inferiores relacionada com a marcha militar. Duas plataformas de força foram usadas para medir as componentes da FRS (mediolateral, anteroposterior e vertical) durante a marcha. Para cada lado e condição (andar e marcha), cinco amostras para cada pé foram registradas. A análise de variância foi utilizada para comparar os parâmetros da FRS durante o andar e marcha. RESULTADO: O primeiro pico de força foi o mais alto durante a condição de marcha. O pico de força transiente durante a marcha foi maior que o primeiro pico durante o andar. A força mínima foi a maior durante a marcha. CONCLUSÃO: A análise das forças de reação do solo marcha militar mostra uma força vertical transiente que não está normalmente presente no padrão de marcha normal. Abstract in spanish INTRODUCCIÓN: El estándar vertical anormal de la fuerza de reacción del suelo (FRS) presenta la asimetría, o más de dos picos, como marcha patológica típica. Una fuerza típica y asimétrica es la fuerza con efecto transiente. ¿Será que la marcha militar es un tipo de marcha patológica? Objetivo: Desc [...] ribir y analizar la fuerza vertical de reacción del suelo durante la fase de apoyo de la marcha militar. MÉTODO: Los participantes fueron 20 soldados del Ejército Brasileño, quienes tuvieron antes una lesión en los miembros inferiores relacionada con la marcha militar. Se usaron dos plataformas de fuerza para medir los componentes de la FRS (mediolateral, anteroposterior y vertical) durante la marcha. Para cada lado y condición (andar y marcha), se registraron cinco muestras para cada pie. El análisis de la variación fue utilizado para comparar los parámetros de la FRS durante el andar y la marcha. RESULTADO: El primer pico de fuerza fue el más alto durante la condición de marcha. El pico de fuerza, con efecto transiente durante la marcha, fue mayor que el primer pico durante el andar. La fuerza mínima fue mayor durante la marcha. CONCLUSIÓN: El análisis de las fuerzas de reacción del suelo, en la marcha militar, muestra una fuerza vertical, con efecto transiente, que normalmente no está presente en el estándar de marcha normal. Abstract in english INTRODUCTION: The abnormal vertical ground reaction force (GRF) pattern presents the asymmetry or the presence of more than two peaks as typical pathological gait. The typical asymmetric force is the transient force. Is the military marching a kind of pathological gait? OBJECTIVE: To describe and an [...] alyze the vertical ground reaction forces during the stance phase of the military marching. METHOD: Participants were 20 Brazilian Army soldiers who previously had an injury in the lower limbs related to the military marching. Two strain-gauge force platforms measured the GRF components (mediolateral, anterior posterior; and vertical components) during gait. To each side and condition (gait and marching) five samples for each foot were recorded. One-way analysis of variance (ANOVA) was used to compare the GRF parameters during gait and marching. RESULTS: The first force peak was the highest during the marching condition. The first force peak was the highest during marching condition. The peak transient force during marching was higher than the first peak during gait. The minimum force was higher during marching. CONCLUSION: The analysis of ground reaction forces in military marching shows a transient vertical force that is not usually present in normal gait pattern.

  7. Force Concept Inventory: Forces and Speed

    Science.gov (United States)

    Wolfgang Christian

    A rocket drifts sideways in outer space from point "a" to point "b" as shown in the animations. The rocket is subject to no outside forces. Starting at position "b", the rockets's engine is turned on and produces a constant thrust (force on the rocket) at right angles to the line "ab". The constant thrust is maintained until the rocket reaches a point "c" in space. At point "c" the rocket's engine is turned off and the thrust immediately drops to zero.

  8. Actin polymerization front propagation in a comb-reaction system

    CERN Document Server

    Iomin, A; Pfohl, T

    2015-01-01

    Anomalous transport and reaction dynamics are considered by providing the theoretical grounds for the possible experimental realization of actin polymerization in comb-like geometry. Two limiting regimes are recovered, depending on the concentration of reagents (magnesium and actin). These are both the failure of the reaction front propagation and a finite speed corresponding to the Fisher-KPP long time asymptotic regime.

  9. Faking It: Coriolis Force

    Science.gov (United States)

    This lesson will help students understand what the Coriolis force is, and what effects it has on objects in motion. Students will be able to describe and explain the Coriolis force, and compare and contrast conditions under which the Coriolis force has a significant impact on objects in motion with conditions under which the influence of the Coriolis force is negligible. Portions of this lesson are based on a webpage called "Bad Coriolis", a resource devoted to correcting misconceptions about the Coriolis force and other natural phenomena.

  10. Ground Beef and Food Safety

    Science.gov (United States)

    ... Standard Forms FSIS United States Department of Agriculture Food Safety and Inspection Service About FSIS District Offices Careers ... JSR 286) Actions ${title} Loading... Ground Beef and Food Safety Questions about "ground meat" or "hamburger" have always ...

  11. Working Through Preconception: Moving from Forcing to Emergence

    OpenAIRE

    Kim Kwok; Antoinette McCallin; Geoff Dickson

    2012-01-01

    Much has been written about grounded theory and the processes of theory generation. Less is written about managing the problem of preconception, which has the potential to undermine the openness and emergence that are fundamental to classic grounded theory. The purpose of this paper is to discuss the practical realities of managing preconception, and to draw attention to less well recognised factors that contribute to forcing. The topic interest, tactical innovation in rugby, is introduced. R...

  12. Force and Motion

    Science.gov (United States)

    National Science Teachers Association (NSTA)

    2007-03-21

    The Force and Motion SciPack explores the effects of forces on the motion of objects. The focus is on topics linked to Standards and Benchmarks related to concepts such as constant motion, acceleration, speed and direction as well as a discussion of Newton's Laws of Motion.In addition to comprehensive inquiry-based learning materials tied to Science Education Standards and Benchmarks, the SciPack includes the following additional components:? Pedagogical Implications section addressing common misconceptions, teaching resources and strand maps linking grade band appropriate content to standards. ? Access to one-on-one support via e-mail to content "Wizards".? Final Assessment which can be used to certify mastery of the concepts.Learning Outcomes:Force and Motion: Position and Motion? Identify the position of one object relative to the position of another object by providing the approximate distance and angles between the objects, the angles being measured from some reference line.? Define the concepts of speed and velocity.? Determine the average speed of an object given necessary information.? Describe, draw, or otherwise detail the velocity of an object given magnitude and direction.? Define acceleration.? Recognize examples of acceleration and provide examples of acceleration.? Distinguish between constant and changing motion.? Distinguish increasing speed from increasing acceleration.? Recognize that the state of rest is a state of zero speed (rather than as something fundamentally different than motion).Force and Motion: Newton's First Law? Recognize and give examples of forces. ? Recognize and give examples of balanced and unbalanced forces.? Equate the term "unbalanced force" with "a net force that does not equal zero."? Apply, in an informal way, Newton's first law. ? Explain the role of the force of friction in determining how well Newton's first law seems to apply or not apply to a given physical situation. ? Explain the reasoning Galileo used to justify the second part of Newton's first law.? Explain how the force of friction applies to the second part of Newton's first law.? Recognize the concept of inertia (as opposed to a force, momentum, etc.). ? Recognize that an object at rest may have forces acting on it.? Distinguish between "impulse" and "sustained" forces (and recognize both).? Recognize that objects do not have internal forces that keep them moving.Force and Motion: Newton's Second Law? Understand that the "F" in F = ma stands for the net force acting on an object, "m" stands for the mass of the object, and "a" stands for the resulting acceleration of the object.? Demonstrate the cause-effect relationship associated with Newton's Second Law--that net forces cause accelerations and not the other way around. ? Know that a net force was applied if an acceleration is observed, and, if the application of a net force is observed, the result will be an acceleration.? State and apply Newton's second law. ? Distinguish between the role of "F" and the role of "m" in Newton's second law. ? Recognize that an object can apply a force to another object, but an object cannot carry a force with it.? Use and interpret ratios and proportions, such as through appropriate use of the phrases "for each," "per"," or "for every."Force and Motion: Newton's Third Law? Explain that when object A exerts a force on object B, object B exerts an equal and opposite force back on object A, regardless of the masses or motion of either object.? Identify the force that B applies on A, given a force that A applies on B.? Recognize that these forces are exerted simultaneously.? Apply this concept in a variety of situations. ? Use Newton's third law to explain how an inanimate object can exert a force on another object.

  13. Quantum fictitious forces

    DEFF Research Database (Denmark)

    Bialynicki-Birula, I; Cirone, M.A.

    2002-01-01

    We present Heisenberg's equation of motion for the radial variable of a free non-relativistic particle in D dimensions. The resulting radial force consists of three contributions: (i) the quantum fictitious force which is either attractive or repulsive depending on the number of dimensions, (ii) a singular quantum force located at the origin, and (iii) the centrifugal force associated with non-vanishing angular momentum. Moreover, we use Heisenberg's uncertainty relation to introduce a lower bound for the kinetic energy of an ensemble of neutral particles. This bound is quadratic in the number of atoms and can be traced back to the repulsive quantum fictitious potential. All three forces arise for a free particle: "Force without force".

  14. Forces in molecules.

    Science.gov (United States)

    Hernández-Trujillo, Jesús; Cortés-Guzmán, Fernando; Fang, De-Chai; Bader, Richard F W

    2007-01-01

    Chemistry is determined by the electrostatic forces acting within a collection of nuclei and electrons. The attraction of the nuclei for the electrons is the only attractive force in a molecule and is the force responsible for the bonding between atoms. This is the attractive force acting on the electrons in the Ehrenfest force and on the nuclei in the Feynman force, one that is countered by the repulsion between the electrons in the former and by the repulsion between the nuclei in the latter. The virial theorem relates these forces to the energy changes resulting from interactions between atoms. All bonding, as signified by the presence of a bond path, has a common origin in terms of the mechanics determined by the Ehrenfest, Feynman and virial theorems. This paper is concerned in particular with the mechanics of interaction encountered in what are classically described as 'nonbonded interactions'--are atoms that 'touch' bonded or repelling one another? PMID:17328425

  15. Isospin dependence of nucleon correlations in ground-state nuclei

    Energy Technology Data Exchange (ETDEWEB)

    Charity, R.J. [Washington University, Department of Chemistry, St. Louis, Missouri (United States); Dickhoff, W.H. [Washington University, Department of Physics, St. Louis, Missouri (United States); Sobotka, L.G. [Washington University, Department of Chemistry, St. Louis, Missouri (United States); Washington University, Department of Physics, St. Louis, Missouri (United States); Waldecker, S.J. [University of Tennessee, Department of Physics, Chattanooga, Tennessee (United States)

    2014-02-15

    The dispersive optical model (DOM) as presently implemented can investigate the isospin (nucleon asymmetry) dependence of the Hartree-Fock-like potential relevant for nucleons near the Fermi energy. Data constraints indicate that a Lane-type potential adequately describes its asymmetry dependence. Correlations beyond the mean field can also be described in this framework, but this requires an extension that treats the non-locality of the Hartree-Fock-like potential properly. The DOM has therefore been extended to properly describe ground-state properties of nuclei as a function of nucleon asymmetry in addition to standard ingredients like elastic nucleon scattering data and level structure. Predictions of nucleon correlations at larger nucleon asymmetries can then be made after data at smaller asymmetries constrain the potentials that represent the nucleon self-energy. A simple extrapolation for Sn isotopes generates predictions for increasing correlations of minority protons with increasing neutron number. Such predictions can be investigated by performing experiments with exotic beams. The predicted neutron properties for the double closed-shell {sup 132}Sn nucleus exhibit similar correlations as those in {sup 208}Pb. Future relevance of these studies for understanding the properties of all nucleons, including those with high momentum, and the role of three-body forces in nuclei are briefly discussed. Such an implementation will require a proper treatment of the non-locality of the imaginary part of the potentials and a description of high-momentum nucleons as experimentally constrained by the (e, e' p) reactions performed at Jefferson Lab. (orig.)

  16. Isospin dependence of nucleon correlations in ground-state nuclei

    International Nuclear Information System (INIS)

    The dispersive optical model (DOM) as presently implemented can investigate the isospin (nucleon asymmetry) dependence of the Hartree-Fock-like potential relevant for nucleons near the Fermi energy. Data constraints indicate that a Lane-type potential adequately describes its asymmetry dependence. Correlations beyond the mean field can also be described in this framework, but this requires an extension that treats the non-locality of the Hartree-Fock-like potential properly. The DOM has therefore been extended to properly describe ground-state properties of nuclei as a function of nucleon asymmetry in addition to standard ingredients like elastic nucleon scattering data and level structure. Predictions of nucleon correlations at larger nucleon asymmetries can then be made after data at smaller asymmetries constrain the potentials that represent the nucleon self-energy. A simple extrapolation for Sn isotopes generates predictions for increasing correlations of minority protons with increasing neutron number. Such predictions can be investigated by performing experiments with exotic beams. The predicted neutron properties for the double closed-shell 132Sn nucleus exhibit similar correlations as those in 208Pb. Future relevance of these studies for understanding the properties of all nucleons, including those with high momentum, and the role of three-body forces in nuclei are briefly discussed. Such an implementation will require a proper treatment of the non-locality of the imaginary part of the potentials and a description of high-momentum nucleons as experimentally constrained by the (e, e' p) reactions performed at Jefferson Lab. (orig.)

  17. TFTR grounding scheme and ground-monitor system

    International Nuclear Information System (INIS)

    The Tokamak Fusion Test Reactor (TFTR) grounding system utilizes a single-point ground. It is located directly under the machine, at the basement floor level, and is tied to the building perimeter ground. Wired to this single-point ground, via individual 500 MCM insulated cables, are: the vacuum vessel; four toroidal field coil cases/inner support structure quadrants; umbrella structure halves; the substructure ring girder; radial beams and columns; and the diagnostic systems. Prior to the first machine operation, a ground-loop removal program was initiated. It required insulation of all hangers and supports (within a 35-foot radius of the center of the machine) of the various piping, conduits, cable trays, and ventilation systems. A special ground-monitor system was designed and installed. It actively monitors each of the individual machine grounds to insure that there are no inadvertent ground loops within the machine structure or its ground and that the machine grounds are intact prior to each pulse. The TFTR grounding system has proven to be a very manageable system and one that is easy to maintain

  18. Attractive optical forces from black-body radiation

    CERN Document Server

    Sonnleitner, Matthias; Ritsch, Helmut

    2013-01-01

    Black-body radiation around hot objects induces AC Stark shifts of the energy levels of nearby atoms and molecules. These shifts are roughly proportional to the fourth power of the temperature and induce a force decaying with the third power of the distance from the object's surface. We explicitly calculate the resulting attractive black-body optical dipole force for ground state hydrogen atoms. Surprisingly this force can surpass the repulsive radiation pressure and actually pull the atoms towards the surface with a force stronger than gravity. We exemplify the dominance of the "black-body force" over gravity for hydrogen in a cloud of hot dust particles. These forces, which have been neglected to date, appear highly relevant in various astrophysical scenarios, in particular since analogous results hold for a wide class of broadband radiation sources.

  19. Kinetics and mechanisms of some atomic oxygen reactions

    Science.gov (United States)

    Cvetanovic, R. J.

    1987-01-01

    Mechanisms and kinetics of some reactions of the ground state of oxygen atoms, O(3P), are briefly summarized. Attention is given to reactions of oxygen atoms with several different types of organic and inorganic compounds such as alkanes, alkenes, alkynes, aromatics, and some oxygen, nitrogen, halogen and sulfur derivatives of these compounds. References to some recent compilations and critical evaluations of reaction rate constants are given.

  20. The Future of Grounded Theory

    Directory of Open Access Journals (Sweden)

    Barney G. Glaser, Ph.D., Hon. Ph.D.

    2010-06-01

    Full Text Available I would like to speak about what I consider the future of grounded theory. I will discuss in whose hands the future of grounded theory appears to be and what accounts for its spread, its use and misuse, and where the majority of grounded theory studies are occurring. I will then briefly review poor grounded theory, qualitative grounded theory, social fictions, and theory bits. Finally, I will touch on the future structures in which grounded theory will be taught and centered.First, a few guidelines are necessary. Grounded theory refers to a specific methodology on how to get from systematically collecting data to producing a multivariate conceptual theory. It is a total methodological package. It provides a series of systematic, exact methods that start with collecting data and take the researcher to a theoretical piece that is publishable.

  1. Cascade enzymatic reactions for efficient carbon sequestration.

    Science.gov (United States)

    Xia, Shunxiang; Zhao, Xueyan; Frigo-Vaz, Benjamin; Zheng, Wenyun; Kim, Jungbae; Wang, Ping

    2015-04-01

    Thermochemical processes developed for carbon capture and storage (CCS) offer high carbon capture capacities, but are generally hampered by low energy efficiency. Reversible cascade enzyme reactions are examined in this work for energy-efficient carbon sequestration. By integrating the reactions of two key enzymes of RTCA cycle, isocitrate dehydrogenase and aconitase, we demonstrate that intensified carbon capture can be realized through such cascade enzymatic reactions. Experiments show that enhanced thermodynamic driving force for carbon conversion can be attained via pH control under ambient conditions, and that the cascade reactions have the potential to capture 0.5 mol carbon at pH 6 for each mole of substrate applied. Overall it manifests that the carbon capture capacity of biocatalytic reactions, in addition to be energy efficient, can also be ultimately intensified to approach those realized with chemical absorbents such as MEA. PMID:25708541

  2. The LOFT Ground Segment

    CERN Document Server

    Bozzo, E; Argan, A; Barret, D; Binko, P; Brandt, S; Cavazzuti, E; Courvoisier, T; Herder, J W den; Feroci, M; Ferrigno, C; Giommi, P; Götz, D; Guy, L; Hernanz, M; Zand, J J M in't; Klochkov, D; Kuulkers, E; Motch, C; Lumb, D; Papitto, A; Pittori, C; Rohlfs, R; Santangelo, A; Schmid, C; Schwope, A D; Smith, P J; Webb, N A; Wilms, J; Zane, S

    2014-01-01

    LOFT, the Large Observatory For X-ray Timing, was one of the ESA M3 mission candidates that completed their assessment phase at the end of 2013. LOFT is equipped with two instruments, the Large Area Detector (LAD) and the Wide Field Monitor (WFM). The LAD performs pointed observations of several targets per orbit (~90 minutes), providing roughly ~80 GB of proprietary data per day (the proprietary period will be 12 months). The WFM continuously monitors about 1/3 of the sky at a time and provides data for about ~100 sources a day, resulting in a total of ~20 GB of additional telemetry. The LOFT Burst alert System additionally identifies on-board bright impulsive events (e.g., Gamma-ray Bursts, GRBs) and broadcasts the corresponding position and trigger time to the ground using a dedicated system of ~15 VHF receivers. All WFM data are planned to be made public immediately. In this contribution we summarize the planned organization of the LOFT ground segment (GS), as established in the mission Yellow Book 1 . We...

  3. Grounding for safety

    Energy Technology Data Exchange (ETDEWEB)

    Prud' homme, P. [Hydro-Quebec, Montreal, PQ (Canada). TransEnergie Div.

    2006-07-01

    The importance of providing electrical grounds as a safety issue in the design of power transmission lines was discussed. Power transmission lines extend over several thousands of kilometers crossing various environments, including communities where electric utilities encourage the use of transmission rights-of-way passages for uses such as bicycle paths. In recent years, many new residential communities have been built at the border of power transmission rights-of-ways or substations. In view of this emerging trend, and the fact that internal statistics indicate that lightning strikes are responsible of about 50 to 60 per cent of transmission line faults, electric utilities are obligated to verify if their installations are safe. Hydro-Quebec TransEnergie's view on this subject was presented along with a review of international standards to determine if limits for touch voltage, step voltage and transferred potential close to transmission lines have been established by the international community. A variety of mitigation measures to control the increase in ground potential in the event of electrical faults were also proposed. tabs., figs.

  4. Empirical ground motion prediction

    Directory of Open Access Journals (Sweden)

    R. J. Archuleta

    1994-06-01

    Full Text Available New methods of site-specific ground motion prediction in the time and frequency domains are presented. A large earthquake is simulated as a composite (linear combination of observed small earthquakes (subevents assuming Aki-Brune functional models of the source time functions (spectra. Source models incorporate basic scaling relations between source and spectral parameters. Ground motion predictions are consistent with the entire observed seismic spectrum from the lowest to the highest frequencies. These methods are designed to use all the available empirical Green?s functions (or any subset of observations at a site. Thus a prediction is not biased by a single record, and different possible source-receiver paths are taken into account. Directivity is accounted for by adjusting the apparent source duration at each site. Our time-series prediction algorithm is based on determination of a non-uniform distribution of rupture times of subevents. By introducing a specific rupture velocity we avoid the major problem of deficiency of predictions around the main event's corner frequency. A novel notion of partial coherence allows us to sum subevents' amplitude spectra directly without using any information on their rupture times and phase histories. Predictions by this spectral method are not Jependent on details of rupture nucleation and propagation, location of asperities and other predominantly phase-affecting factors, responsible for uncertainties in time-domain simulations.

  5. The Coulomb Force as an Entropic Force

    CERN Document Server

    Wang, Tower

    2010-01-01

    Motivated by Verlinde's theory of entropic gravity, we give a tentative explain to the Coulomb's law with an entropic force. When trying to do this, we find the equipartition rule should be extended to charges and the concept of temperature should be reinterpreted. If one accepts the holographic principle as well as our generalizations and reinterpretations, then the coulomb's law, the Poisson's equation and the Maxwell's equations can be derived smoothly. Our attempt can be regarded as a new way to unify the electromagnetic force with gravity, from the entropic origin. Possibly some of our postulate are related to the D-brane picture of black hole thermodynamics.

  6. Coulomb force as an entropic force

    Science.gov (United States)

    Wang, Tower

    2010-05-01

    Motivated by Verlinde’s theory of entropic gravity, we give a tentative explanation to the Coulomb’s law with an entropic force. When trying to do this, we find the equipartition rule should be extended to charges and the concept of temperature should be reinterpreted. If one accepts the holographic principle as well as our generalizations and reinterpretations, then Coulomb’s law, the Poisson equation, and the Maxwell equations can be derived smoothly. Our attempt can be regarded as a new way to unify the electromagnetic force with gravity, from the entropic origin. Possibly some of our postulates are related to the D-brane picture of black hole thermodynamics.

  7. Relativistic Linear Restoring Force

    Science.gov (United States)

    Clark, D.; Franklin, J.; Mann, N.

    2012-01-01

    We consider two different forms for a relativistic version of a linear restoring force. The pair comes from taking Hooke's law to be the force appearing on the right-hand side of the relativistic expressions: d"p"/d"t" or d"p"/d["tau"]. Either formulation recovers Hooke's law in the non-relativistic limit. In addition to these two forces, we…

  8. Debunking Coriolis Force Myths

    Science.gov (United States)

    Shakur, Asif

    2014-11-01

    Much has been written and debated about the Coriolis force.1-8 Unfortunately, this has done little to demystify the paradoxes surrounding this fictitious force invoked by an observer in a rotating frame of reference. It is the purpose of this article to make another valiant attempt to slay the dragon of the Coriolis force! This will be done without unleashing the usual mathematical apparatus, which we believe is more of a hindrance than a help.

  9. Asymmetric Electrostatic Force

    OpenAIRE

    Katsuo Sakai

    2014-01-01

    Asymmetric electrostatic forces are a very interesting and new phenomenon. The magnitude of an electrostatic force that acts on a point charge does not change when the direction of the electric field is reversed. On the contrary, the magnitude of the electrostatic force that acts on a charged asymmetric shaped conductor does change when the direction of the electric field is reversed. 5 years ago, this phenomenon was reported by a simple experiment and a simulation and named as an Asymmetric ...

  10. Exploring medium effects on the nuclear force

    Energy Technology Data Exchange (ETDEWEB)

    F. Sammarruca

    2004-04-18

    This STI product contains a description of results from theoretical studies in nuclear physics. The goal is a systematic investigation of the nuclear force in the nuclear medium. The problems addressed are: density-dependent effective interactions as seen through proton-nucleus reactions, nuclear matter with unequal densities of protons and neutrons, applications to asymmetric nuclei through predictions of neutron radii and neutron skins.

  11. Charm production and the confining force field

    International Nuclear Information System (INIS)

    We show that charm production at SPS energies can be understood simply from O(?2 sub (s)) QCD processes when combined with fragmentation of the colour fields stretched by the final state partons. The tension of the confining force field responsible for particle production is found to pull the charmed particles away from the reaction centre, giving rise to a harder x sub (F)-spectrum than would be expected from the bare QCD matrix elements. (Authors)

  12. Exploring medium effects on the nuclear force

    International Nuclear Information System (INIS)

    This STI product contains a description of results from theoretical studies in nuclear physics. The goal is a systematic investigation of the nuclear force in the nuclear medium. The problems addressed are: density-dependent effective interactions as seen through proton-nucleus reactions, nuclear matter with unequal densities of protons and neutrons, applications to asymmetric nuclei through predictions of neutron radii and neutron skins

  13. Force induced DNA melting

    International Nuclear Information System (INIS)

    When pulled along the axis, double-strand DNA undergoes a large conformational change and elongates by roughly twice its initial contour length at a pulling force of about 70 pN. The transition to this highly overstretched form of DNA is very cooperative. Applying a force perpendicular to the DNA axis (unzipping), double-strand DNA can also be separated into two single-stranded DNA, this being a fundamental process in DNA replication. We study the DNA overstretching and unzipping transition using fully atomistic molecular dynamics (MD) simulations and argue that the conformational changes of double-strand DNA associated with either of the above mentioned processes can be viewed as force induced DNA melting. As the force at one end of the DNA is increased the DNA starts melting abruptly/smoothly above a critical force depending on the pulling direction. The critical force fm, at which DNA melts completely decreases as the temperature of the system is increased. The melting force in the case of unzipping is smaller compared to the melting force when the DNA is pulled along the helical axis. In the case of melting through unzipping, the double-strand separation has jumps which correspond to the different energy minima arising due to sequence of different base pairs. The fraction of Watson-Crick base pair hydrogen bond breaking as a function of force does not show smooth and continuous behavior and consists of plateaus followed by sharp jumps.followed by sharp jumps.

  14. Force induced DNA melting

    Energy Technology Data Exchange (ETDEWEB)

    Santosh, Mogurampelly; Maiti, Prabal K [Center for Condensed Matter Theory, Department of Physics, Indian Institute of Science, Bangalore-12 (India)], E-mail: santosh@physics.iisc.ernet.in, E-mail: maiti@physics.iisc.ernet.in

    2009-01-21

    When pulled along the axis, double-strand DNA undergoes a large conformational change and elongates by roughly twice its initial contour length at a pulling force of about 70 pN. The transition to this highly overstretched form of DNA is very cooperative. Applying a force perpendicular to the DNA axis (unzipping), double-strand DNA can also be separated into two single-stranded DNA, this being a fundamental process in DNA replication. We study the DNA overstretching and unzipping transition using fully atomistic molecular dynamics (MD) simulations and argue that the conformational changes of double-strand DNA associated with either of the above mentioned processes can be viewed as force induced DNA melting. As the force at one end of the DNA is increased the DNA starts melting abruptly/smoothly above a critical force depending on the pulling direction. The critical force f{sub m}, at which DNA melts completely decreases as the temperature of the system is increased. The melting force in the case of unzipping is smaller compared to the melting force when the DNA is pulled along the helical axis. In the case of melting through unzipping, the double-strand separation has jumps which correspond to the different energy minima arising due to sequence of different base pairs. The fraction of Watson-Crick base pair hydrogen bond breaking as a function of force does not show smooth and continuous behavior and consists of plateaus followed by sharp jumps.

  15. Theory of intermolecular forces

    CERN Document Server

    Margenau, H; Ter Haar, D

    1971-01-01

    Theory of Intermolecular Forces deals with the exposition of the principles and techniques of the theory of intermolecular forces. The text focuses on the basic theory and surveys other aspects, with particular attention to relevant experiments. The initial chapters introduce the reader to the history of intermolecular forces. Succeeding chapters present topics on short, intermediate, and long range atomic interactions; properties of Coulomb interactions; shape-dependent forces between molecules; and physical adsorption. The book will be of good use to experts and students of quantum mechanics

  16. The Rotational Spectrum and Anharmonic Force Field of Chlorine Dioxide, OClO

    Science.gov (United States)

    Muller, Holger S. P.; Sorensen, G.; Birk, Manfred; Friedl, Randy R.

    1997-01-01

    The ground state rotational and quartic centrifugal distortion constants, their vibrational changes, and the sextic centrifugal distortion constants were used in a calculation of the quartic force field together with data from infrared studies.

  17. The Casimir effect: a force from nothing

    International Nuclear Information System (INIS)

    The attractive force between two surfaces in a vacuum - first predicted by Hendrik Casimir over 50 years ago - could affect everything from micromachines to unified theories of nature. What happens if you take two mirrors and arrange them so that they are facing each other in empty space? Your first reaction might be 'nothing at all'. In fact, both mirrors are mutually attracted to each other by the simple presence of the vacuum. This startling phenomenon was first predicted in 1948 by the Dutch theoretical physicist Hendrik Casimir while he was working at Philips Research Laboratories in Eindhoven on - of all things - colloidal solutions (see box). The phenomenon is now dubbed the Casimir effect, while the force between the mirrors is known as the Casimir force. For many years the Casimir effect was little more than a theoretical curiosity. But interest in the phenomenon has blossomed in recent years. Experimental physicists have realized that the Casimir force affects the workings of micromachined devices, while advances in instrumentation have enabled the force to be measured with ever-greater accuracy. The new enthusiasm has also been fired by fundamental physics. Many theorists have predicted the existence of 'large' extra dimensions in 10- and 11-dimensional unified field theories of the fundamental forces. These dimensions, they say, could modify classical Newtonian gravitation at sub-millimetre distances. Measuring the Casimir effect could therefore help physi Casimir effect could therefore help physicists to test the validity of such radical ideas. (U.K.)

  18. Staying Open: The use of theoretical codes in grounded theory

    Directory of Open Access Journals (Sweden)

    Barney G. Glaser, PhD., Hon. PhD.

    2005-11-01

    Full Text Available Theoretical codes (TCs are abstract models that emerge during the sorting and memoing stages of grounded theory (GT analysis. They conceptualize the integration of substantive codes as hypotheses of a theory. In this article, I explore the importance of their emergence in the development of a grounded theory and I discuss the challenge of the researcher in staying open to their emergence and earned relevance rather than their preconceived forcing on the theory under development. I emphasize the importance of GT researchers developing theoretical sensitivity to a wide range of theoretical perspectives and their associated codes. It is a skill that all GT researchers can and should develop.

  19. Applying Grounded Theory

    Directory of Open Access Journals (Sweden)

    Barney G. Glaser, PhD, Hon. PhD

    2014-06-01

    Full Text Available Application of grounded theory (GT is a relatively neglected topic by my colleagues. I have written several chapters in my books on applying GT. Two colleagues, Odis Simmons and Barbara Artinian (2009, as well as Dirks and Mills (2011, and Walsh (2014, have also written about applying GT. In the first two chapters of this book I discuss at length properties of generally applying GT and then professional issues and personal matters when applying of GT. There follows in this book nine chapters, four by me and one by Simmons and one by Artinian and one by Dirks and Mills, that are already published in books on GT, and one by Walsh. Thus, this book ends like a reader which publishes in one place already written work. The reader of this book may experience some redundancy in these chapters, but that is the nature of reader texts as different authors discuss the same ideas and topics.

  20. Decentralized Ground Staff Scheduling

    DEFF Research Database (Denmark)

    SØrensen, M. D.; Clausen, Jens

    2002-01-01

    Typically, ground staff scheduling is centrally planned for each terminal in an airport. The advantage of this is that the staff is efficiently utilized, but a disadvantage is that staff spends considerable time walking between stands. In this paper a decentralized approach for ground staff scheduling is investigated. The airport terminal is divided into zones, where each zone consists of a set of stands geographically next to each other. Staff is assigned to work in only one zone and the staff scheduling is planned decentralized for each zone. The advantage of this approach is that the staff work in a smaller area of the terminal and thus spends less time walking between stands. When planning decentralized the allocation of stands to flights influences the staff scheduling since the workload in a zone depends on which flights are allocated to stands in the zone. Hence solving the problem depends on the actual stand allocation but also on the number of zones and the layout of these. A mathematical model of the problem is proposed, which integrates the stand allocation and the staff scheduling. A heuristic solution method is developed and applied on a real case from British Airways, London Heathrow Airport. This study shows that decentralization generally increases the number of staff needed compared to centralized planning. The case study also shows that there is a trade-off between the extra staff needed and the quality of the stand allocation. Furthermore, the robustness of solutions with respect to disruptions deteriorates with the number of zones. In practice, the "cost" of introducing decentralization should therefore be weighted against the benefits gained.

  1. SOFIE instrument ground calibration

    Science.gov (United States)

    Hansen, Scott; Fish, Chad; Romrell, Devin; Gordley, Larry; Hervig, Mark

    2006-08-01

    Space Dynamics Laboratory (SDL), in partnership with GATS, Inc., designed and built an instrument to conduct the Solar Occultation for Ice Experiment (SOFIE). SOFIE is the primary infrared sensor in the NASA Aeronomy of Ice in the Mesosphere (AIM) instrument suite. AIM's mission is to study polar mesospheric clouds (PMCs). SOFIE will make measurements in 16 separate spectral bands, arranged in eight pairs between 0.29 and 5.3 ?m. Each band pair will provide differential absorption limb-path transmission profiles for an atmospheric component of interest, by observing the sun through the limb of the atmosphere during solar occultation as AIM orbits Earth. A pointing mirror and imaging sun sensor coaligned with the detectors are used to track the sun during occultation events and maintain stable alignment of the sun on the detectors. Ground calibration experiments were performed to measure SOFIE end-to-end relative spectral response, nonlinearity, and spatial characteristics. SDL's multifunction infrared calibrator #1 (MIC1) was used to present sources to the instrument for calibration. Relative spectral response (RSR) measurements were performed using a step-scan Fourier transform spectrometer (FTS). Out-of-band RSR was measured to approximately 0.01% of in-band peak response using the cascaded filter Fourier transform spectrometer (CFFTS) method. Linearity calibration was performed using a calcium fluoride attenuator in combination with a 3000K blackbody. Spatial characterization was accomplished using a point source and the MIC1 pointing mirror. SOFIE sun sensor tracking algorithms were verified using a heliostat and relay mirrors to observe the sun from the ground. These techniques are described in detail, and resulting SOFIE performance parameters are presented.

  2. On Thermonuclear Reaction Rates

    CERN Document Server

    Haubold, H J; Haubold, Hans J.; Mathai, Arak Mathai

    1996-01-01

    Nuclear reactions govern major aspects of the chemical evolution od galaxies and stars. Analytic study of the reaction rates and reaction probability integrals is attempted here. Exact expressions for the reaction rates and reaction probability integrals for nuclear reactions in the case of nonresonant, modified nonresonant, screened nonresonant and resonant cases are given. These are expressed in terms of H-functions, G-functions and in computable series forms. Computational aspects are also discussed.

  3. Theoretical studies of reaction surfaces

    Science.gov (United States)

    Gordon, Mark S.

    1994-08-01

    The main goals in the previous grant period have been to develop new, more effective methods for performing accurate ab initio electronic structure calculations and to use these methods for the prediction of molecular structure, bonding and reactivity, especially for main group species and reactions of interest to the Air Force. From the theoretical point of view, the principle accomplishments have been extensive development of approaches and codes for performing electronic structure calculations in parallel, continued development of methods for interfacing electronic structure calculations with dynamics, initial studies of the possibility of splicing together different levels of electronic structure theory, and the development of a new model for treating solvation. Applications have ranged from the development of very accurate and extensive potential energy surfaces for A +HB reactions (to interface with the experiments) to the role of catalysts in the hydrosilation reaction to extensive studies of reactions involved in both main group and transition metal chemical vapor deposition (CVD) to broad-based studies of cage molecules (using our new parallel capabilities) that are potential precursors for new materials electronic and optical devices and catalysts. A new area that we have entered into is a series of systematic calculations on transition metal(TM)-main group (MG) compounds and their roles and catalysts and in such important area as CVD.

  4. Forces in yeast flocculation

    Science.gov (United States)

    El-Kirat-Chatel, Sofiane; Beaussart, Audrey; Vincent, Stéphane P.; Abellán Flos, Marta; Hols, Pascal; Lipke, Peter N.; Dufrêne, Yves F.

    2015-01-01

    In the baker's yeast Saccharomyces cerevisiae, cell-cell adhesion (``flocculation'') is conferred by a family of lectin-like proteins known as the flocculin (Flo) proteins. Knowledge of the adhesive and mechanical properties of flocculins is important for understanding the mechanisms of yeast adhesion, and may help controlling yeast behaviour in biotechnology. We use single-molecule and single-cell atomic force microscopy (AFM) to explore the nanoscale forces engaged in yeast flocculation, focusing on the role of Flo1 as a prototype of flocculins. Using AFM tips labelled with mannose, we detect single flocculins on Flo1-expressing cells, showing they are widely exposed on the cell surface. When subjected to force, individual Flo1 proteins display two distinct force responses, i.e. weak lectin binding forces and strong unfolding forces reflecting the force-induced extension of hydrophobic tandem repeats. We demonstrate that cell-cell adhesion bonds also involve multiple weak lectin interactions together with strong unfolding forces, both associated with Flo1 molecules. Single-molecule and single-cell data correlate with microscale cell adhesion behaviour, suggesting strongly that Flo1 mechanics is critical for yeast flocculation. These results favour a model in which not only weak lectin-sugar interactions are involved in yeast flocculation but also strong hydrophobic interactions resulting from protein unfolding.

  5. Multivariate Force of Mortality

    CERN Document Server

    Rao, Arni S R Srinivasa

    2011-01-01

    We introduce bi-variate and multivariate force of mortality functions. The pattern of mortality in a population is one of the strong influencing factors in determining the life expectancies at various ages in the population. Multiple reasons behind declining forces of mortality could be studied using the proposed functions.

  6. Investigation of Ground Frequency Characteristics

    Directory of Open Access Journals (Sweden)

    Mohamed Nayel

    2013-08-01

    Full Text Available Four-electrode method is one of the well-known methods in measuring ground resistivity. But, most faults currents and lightning currents have high frequencies components. It is proposed to develop this method to study ground frequency characteristics. A step like current was injected into ground to measure the ground impedance. The ground impedance is assumed to be frequency dependent parallel resistance/capacitance. Two equations were proved to estimate ground resistivity and permittivity from four-electrode method. An analytical model was proposed to model studied cases. The four electrodes are divided to equal spheres and complex image method had been used to satisfy the boundary conditions and penetration depth effects. The calculated results show good agreement with the measured results.

  7. Solar Force-free Magnetic Fields

    Directory of Open Access Journals (Sweden)

    Thomas Wiegelmann

    2012-09-01

    Full Text Available The structure and dynamics of the solar corona is dominated by the magnetic field. In most areas in the corona magnetic forces are so dominant that all non-magnetic forces like plasma pressure gradient and gravity can be neglected in the lowest order. This model assumption is called the force-free field assumption, as the Lorentz force vanishes. This can be obtained by either vanishing electric currents (leading to potential fields or the currents are co-aligned with the magnetic field lines. First we discuss a mathematically simpler approach that the magnetic field and currents are proportional with one global constant, the so-called linear force-free field approximation. In the generic case, however, the relation between magnetic fields and electric currents is nonlinear and analytic solutions have been only found for special cases, like 1D or 2D configurations. For constructing realistic nonlinear force-free coronal magnetic field models in 3D, sophisticated numerical computations are required and boundary conditions must be obtained from measurements of the magnetic field vector in the solar photosphere. This approach is currently of large interests, as accurate measurements of the photospheric field become available from ground-based (for example SOLIS and space-born (for example Hinode and SDO instruments. If we can obtain accurate force-free coronal magnetic field models we can calculate the free magnetic energy in the corona, a quantity which is important for the prediction of flares and coronal mass ejections. Knowledge of the 3D structure of magnetic field lines also help us to interpret other coronal observations, e.g., EUV images of the radiating coronal plasma.

  8. Ground Attenuation of Railroad Noise

    DEFF Research Database (Denmark)

    Makarewicz, R.; Rasmussen, Karsten Bo

    1996-01-01

    The influence of ground effect on railroad noise is described using the concept of the peak A-weighted sound exposure level, and A-weighted sound exposure level. The train is modelled by a continuous line of incoherent point sources that have a cosine directivity. The ground effect is included by the Weyl van der Pol solution with the single parameter model of the ground impedance. The method of determining of the referenced A-weighted power spectrum is presented.

  9. Regional ground-water system

    International Nuclear Information System (INIS)

    The Containment and Isolation Working Group considered issues related to the postclosure behavior of repositories in crystalline rock. This working group was further divided into subgroups to consider the progress since the 1978 GAIN Symposium and identify research needs in the individual areas of regional ground-water flow, ground-water travel time, fractional release, and cumulative release. The analysis and findings of the Ground-Water Regime Subgroup are presented

  10. ITER ICRH antenna grounding options

    International Nuclear Information System (INIS)

    Highlights: ? There is a clearance gap between the ITER ICRF antenna plug and the vacuum vessel. ? TEM and TE modes can be excited in this gap in the ITER frequency band. ? Galvanic grounding at 1 m from the antenna front is proposed to solve this issue. ? Experimental measurements and numerical simulations validate the proposed solution. -- Abstract: To avoid the excitation of modes in the 20 mm clearance gap between the ITER ICRH antenna plug and the vacuum vessel in the ITER frequency band it was proposed to perform galvanic grounding at 1 m from the antenna plug front. Experimental S-matrix and gap voltage measurements on a reduced-scale mock-up of the ITER ICRH antenna as well as numerical simulations show indeed that the frequency response of the antenna array is perturbed by a TE0,1 mode resonance in the ITER frequency band (around 45 MHz) in absence of any additional grounding and may lead to large voltages in the clearance gap. They also confirm the efficiency of the proposed grounding solution. Grounding all around the antenna plug periphery (“full” grounding) is compared to grounding with discrete contacts (“partial” grounding). The influence of the position of the grounding is also studied. Eigen modes analysis allows identifying the modes experimentally observed. Finally a practical solution considered for implementation on ITER is validated both by numerical simulations and experimental measurements

  11. Ship Collision and Grounding Analysis

    DEFF Research Database (Denmark)

    Pedersen, Preben Terndrup

    2010-01-01

    It is the purpose of the paper to present a review of prediction and analysis tools for collision and grounding analyses and to outline a probabilistic procedure whereby these tools can be used by the maritime industry to develop performance based rules to reduce the risk associated with human, environmental and economic costs of collision and grounding events. The main goal of collision and grounding research should be to identify the most economic risk control options associated with prevention and mitigation of collision and grounding events

  12. Influence of soil conditioning on ground deformation during longitudinal tunneling

    Science.gov (United States)

    Jiang, Mingjing; Yin, Zhen-Yu

    2014-03-01

    Soil conditioning is often adopted to facilitate EPB shield tunneling. However, the resulting improvement of soil fluidity and the reduction of friction forces will also raise the ground deformation problem. This paper aims to investigate the influence of soil conditioning on the ground deformation during longitudinal tunneling. DEM is employed for this study due to its advantages in analyzing large deformations and discontinuous processes. Soil conditioning is modeled by reducing the interparticle friction of soils in a specific zone around the cutterhead of the tunnel. The tunnel advance with different soil-conditioning treatments is thus modeled. Comparisons are carried out on the ground deformation, i.e. ground surface settlement, vertical and horizontal displacements. The influence of soil conditioning on the ground deformation is clarified, and is associated with the fluidity from poor to favorite, and the mechanical properties from dilative to contractive are associated with the increase of soil conditioning. The results are helpful to determine the conditioned soils and control ground deformation for real constructions.

  13. Ground-water contamination by petroleum hydrocarbons: Natural biodegradation in a dynamic hydrologic and geochemical system

    International Nuclear Information System (INIS)

    A surficial aquifer contaminated with gasoline was studied as part of the US Geological Survey Toxic Substances Hydrology Program to determine how ground-water chemistry is controlled by microbial degradation processes. This paper presents a study of the temporal changes in hydrologic and geochemical conditions in an aquifer in the Atlantic coastal plain that was affected by hydrocarbon contaminants. The biogeochemical reactions and the resulting chemical composition of shallow ground water were controlled by (1) microbially-mediated reactions that occurred at a small spatial scale, and by (2) changes in these reactions over time due to mixing with infiltrating water, and rising and falling water levels. The concentration gradients observed in contaminated ground water were complicated by seasonal changes in the local hydrology that caused variability in the availability of electron acceptors. Shifts in the biogeochemical reactions occurred rapidly in response to these changes in the hydrogeochemical conditions

  14. The reliability of linear position transducer, force plate and combined measurement of explosive power-time variables during a loaded jump squat in elite athletes.

    Science.gov (United States)

    Hansen, Keir T; Cronin, John B; Newton, Michael J

    2011-03-01

    The purpose of this study was to determine the between day reliability of power-time measures calculated with data collected using the linear position transducer or the force plate independently, or a combination of the two technologies. Twenty-five male rugby union players performed three jump squats on two occasions one week apart. Ground reaction forces were measured via a force plate and position data were collected using a linear position transducer. From these data, a number of power-time variables were calculated for each method. The force plate, linear position transducer and a combined method were all found to be a reliable means of measuring peak power (ICC = 0.87-0.95, CV = 3.4%-8.0%). The absolute consistency of power-time measures varied between methods (CV = 8.0%-53.4%). Relative consistency of power-time measures was generally comparable between methods and measures, and for many variables was at an acceptable level (ICC = 0.77-0.94). Although a number of time-dependent power variables can be reliably calculated from data acquired from the three methods investigated, the reliability of a number of these measures is below that which is acceptable for use in research and for practical applications. PMID:21560751

  15. Isomer ratios for the reactions ? + 70Ge

    International Nuclear Information System (INIS)

    Isomer ratios for 73Se sup(m,g), produced in the reaction ? + 70Ge, with incident laboratory energy ranging from 8 to 28 MeV, have been deduced using off-line ?-ray spectroscopy. Relative cross-section for isomeric and ground states formation were obtained with sup(nat) Ge targets. Compound nucleus statistical analyses were performed with the codes ALICE and JULIAN, and a good agreement was obtained between predictions of JULIAN and the experimental results. Angular momentum populations of for isomer formation have been determined in the 70Ge (?, n)73Se reaction. (Author)

  16. The geometry of generalized force matching in coarse-graining and related information metrics

    CERN Document Server

    Kalligiannaki, Evangelia; Katsoulakis, Markos A; Plechac, Petr

    2015-01-01

    Using the probabilistic language of conditional expectations we reformulate the force matching method for coarse-graining of molecular systems as a projection on spaces of coarse observables. A practical outcome of this probabilistic description is the link of the force matching method with thermodynamic integration. This connection provides a way to systematically construct a local mean force in order to optimally approximate the potential of mean force through force matching. We introduce a generalized force matching condition for the local mean force in the sense that allows the approximation of the potential of mean force under both linear and non-linear coarse graining mappings (e.g., reaction coordinates, end-to-end length of chains). Furthermore, we study the equivalence of force matching with relative entropy minimization which we derive for general non-linear coarse graining maps. We present in detail the generalized force matching condition through applications to specific examples in molecular syst...

  17. Nuclear ground state properties with the Skyrme interaction

    International Nuclear Information System (INIS)

    Results concerning nuclear ground state properties obtained by Hartree-Fock calculations using the Skyrme's force are summarized. It is shown that a Skyrme Hartree-Fock method is able to reproduce the total binding energies of all nuclei of the chart table with a maximal discrepancy of 5 MeV. Charge radii and single particle spectra are also correctly calculated. The extrapolation of these calculations to exotic sodium isotopes and superheavy elements is presented and discussed

  18. Active and Passive Flow Control around Simplified Ground Vehicles

    Directory of Open Access Journals (Sweden)

    C.H Bruneau

    2012-01-01

    Full Text Available The aim of this work is to control the flow around ground vehicles by active or/and passive strategies. The active control is achieved by steady, pulsed or closed-loop jets located at the backof the simplified car model. The passive control is performed using porous layers between the solid body and the fluid in order to modify the shear forces. The two previous control methods can be coupled to improve the drag reduction.

  19. OOTW Force Design Tools

    Energy Technology Data Exchange (ETDEWEB)

    Bell, R.E.; Hartley, D.S.III; Packard, S.L.

    1999-05-01

    This report documents refined requirements for tools to aid the process of force design in Operations Other Than War (OOTWs). It recommends actions for the creation of one tool and work on other tools relating to mission planning. It also identifies the governmental agencies and commands with interests in each tool, from whom should come the user advisory groups overseeing the respective tool development activities. The understanding of OOTWs and their analytical support requirements has matured to the point where action can be taken in three areas: force design, collaborative analysis, and impact analysis. While the nature of the action and the length of time before complete results can be expected depends on the area, in each case the action should begin immediately. Force design for OOTWs is not a technically difficult process. Like force design for combat operations, it is a process of matching the capabilities of forces against the specified and implied tasks of the operation, considering the constraints of logistics, transport and force availabilities. However, there is a critical difference that restricts the usefulness of combat force design tools for OOTWs: the combat tools are built to infer non-combat capability requirements from combat capability requirements and cannot reverse the direction of the inference, as is required for OOTWs. Recently, OOTWs have played a larger role in force assessment, system effectiveness and tradeoff analysis, and concept and doctrine development and analysis. In the first Quadrennial Defense Review (QDR), each of the Services created its own OOTW force design tool. Unfortunately, the tools address different parts of the problem and do not coordinate the use of competing capabilities. These tools satisfied the immediate requirements of the QDR, but do not provide a long-term cost-effective solution.

  20. Choosing Grounded Theory

    Directory of Open Access Journals (Sweden)

    Barney G. Glaser, PhD, Hon. PhD

    2014-12-01

    Full Text Available This book deals simply with choosing classic grounded theory (CGT as the methodology to use mainly for doing the dissertation. CGT stands alone as a separate method, not as a competitive method in conflict and controversy with all the QDA (qualitative data analysis methods jargonized as a type of GT. The PhD candidate (herein called novice simply chooses the method that he/she wants as best fit for him. This reader provides a myriad of CGT properties to consider in choosing it as the method to use. There will be no competitive arguments with other methods offered here. It is designed to have CGT chosen on its merits for the user, not better or worse. Other GT methods are just different, not better or worse. So to competitively compare them violates the Glaser purpose here to no advantage. Privately many novices may choose CGT over other methods for personal reasons, such as preferring emergence, autonomy, coding and no preconceptions, etc. but the choice is private, not better or worse. Also CGT is not to be mixed with other methods. The choice of CGT is solo pure.

  1. Forced Migration Projects

    Science.gov (United States)

    The Forced Migration Projects (FMP), operating under the auspices of the Open Society Institute (OSI), monitor developments in the Americas, the former Yugoslavia, and the former Soviet Union to identify the social, political, and economic conditions that cause the forced dislocations of people. This Website provides background information about the projects as well as full-text access to several FMP publications including The Forced Migration Monitor, a series of special reports on refugees and migration, recent news and articles on germane issues, and FM Alert, an electronic bulletin service. In addition, the site compiles a list of refugee-related links and hosts a discussion forum.

  2. The Glyoxal Clock Reaction

    Science.gov (United States)

    Ealy, Julie B.; Negron, Alexandra Rodriguez; Stephens, Jessica; Stauffer, Rebecca; Furrow, Stanley D.

    2007-01-01

    Research on the glyoxal clock reaction has led to adaptation of the clock reaction to a general chemistry experiment. This particular reaction is just one of many that used formaldehyde in the past. The kinetics of the glyoxal clock makes the reaction suitable as a general chemistry lab using a Calculator Based Laboratory (CBL) or a LabPro. The…

  3. AN EXCAVATION FORCE CALCULATIONS AND APPLICATIONS: AN ANALYTICAL APPROACH

    Directory of Open Access Journals (Sweden)

    BHARGAV J. GADHVI

    2011-05-01

    Full Text Available A better tool design in the excavation process has been always a challenging task for the engineers. A poorly designed tool always results in poor excavation of the ground, higher wear of the tool, wastage of the time, and power, and thus reducing the overall productivity of the excavation operation. But proper understanding of the soil mechanics in context of the soil cutting process may help in a better tool design. Moreover; in designing the control system for an excavator requires the dynamic model of an excavator, and it requires in turn the resistive forces offered by the ground on the bucket. The excavation forces necessary to cut the soil by the excavator bucket have been analyzed in this paper to improve the design of the bucket teeth, the leap plate of the bucket,and the side cutting plates. The method used for calculating the excavation force is based on 2D analytical soiltool interaction models.

  4. Ground-State Electromagnetic Moments of Calcium Isotopes

    CERN Document Server

    Ruiz, R F Garcia; Blaum, K; Frommgen, N; Hammen, M; Holt, J D; Kowalska, M; Kreim, K; Menendez, J; Neugart, R; Neyens, G; Nortershauser, W; Nowacki, F; Papuga, J; Poves, A; Schwenk, A; Simonis, J; Yordanov, D T

    2015-01-01

    High-resolution bunched-beam collinear laser spectroscopy was used to measure the optical hyperfine spectra of the $^{43-51}$Ca isotopes. The ground state magnetic moments of $^{49,51}$Ca and quadrupole moments of $^{47,49,51}$Ca were measured for the first time, and the $^{51}$Ca ground state spin $I=3/2$ was determined in a model-independent way. Our results provide a critical test of modern nuclear theories based on shell-model calculations using phenomenological as well as microscopic interactions. The results for the neutron-rich isotopes are in excellent agreement with predictions using interactions derived from chiral effective field theory including three-nucleon forces, while lighter isotopes illustrate the presence of particle-hole excitations of the $^{40}$Ca core in their ground state.

  5. Coulomb Interaction as the Source of Muscle Force

    OpenAIRE

    Rosenfeld, E. V.

    2007-01-01

    Myosin motor is the machine, which performs mechanical work in the course of adenosine triphosphate molecule hydrolysis and myosin head conformations accompanying this process. For displacement of individual fragments of large molecule relative to each other to arise and work to be performed, force must be born inside protein. What kind of interaction generates this force? Models based on Huxley 1957 theory ascertain relations between chemical reactions rate constants and ...

  6. On LHCb muon MWPC grounding

    CERN Document Server

    Kashchuk, A

    2006-01-01

    My goal is to study how a big MWPC system, in particular the LHCb muon system, can be protected against unstable operation and multiple spurious hits, produced by incorrect or imperfect grounding in the severe EM environment of the LHCb experiment. A mechanism of penetration of parasitic current from the ground loop to the input of the front-end amplifier is discussed. A new model of the detector cell as the electrical bridge is considered. As shown, unbalance of the bridge makes detector to be sensitive to the noise in ground loop. Resonances in ground loop are specified. Tests of multiple-point and single-point grounding conceptions made on mock-up are presented.

  7. 2. Nuclear reactions

    International Nuclear Information System (INIS)

    The types of nuclear reactions are systematically classified, their mechanism, kinetics and energy balance explained. Natural and artificial radionuclides are reviewed and the methods of calculating their decay shown. The concept of cross section is explained and the calculation is shown of nuclear reaction yields. The problems are discussed of high energy particle reactions, fission reactions, and spontaneous and controlled thermonuclear reactions. (M.D.)

  8. Relativistic Linear Restoring Force

    CERN Document Server

    Clark, D; Mann, N

    2012-01-01

    We consider two different forms for a relativistic version of a linear restoring force. The pair comes from taking Hooke's law to be the force appearing on the right of the relativistic expressions: dp/dt or dp/dtau . Either formulation recovers Hooke's law in the non-relativistic limit. In addition to these two forces, we introduce a form of retardation appropriate for the description of a linear (in displacement) force arising from the interaction of a pair of particles with a relativistic field. The procedure is akin to replacing Coulomb's law in E&M with a retarded form (the first correction in the full relativistic case). This retardation leads to the expected oscillation, but with amplitude growth in both its relativistic and non-relativistic incarnations.

  9. Relativistic linear restoring force

    International Nuclear Information System (INIS)

    We consider two different forms for a relativistic version of a linear restoring force. The pair comes from taking Hooke’s law to be the force appearing on the right-hand side of the relativistic expressions: dp/dt or dp/d?. Either formulation recovers Hooke’s law in the non-relativistic limit. In addition to these two forces, we introduce a form of retardation appropriate for the description of a linear (in displacement) force arising from the interaction of a pair of particles with a relativistic field. The procedure is akin to replacing Coulomb’s law in electromagnetism with a retarded form (the first correction in the full relativistic case). This retardation leads to the expected oscillation, but with amplitude growth in both its relativistic and non-relativistic incarnations. (paper)

  10. Conservative entropic forces

    CERN Document Server

    Visser, Matt

    2011-01-01

    Entropic forces have recently attracted considerable attention as ways to reformulate, retrodict, and perhaps even "explain'" classical Newtonian gravity from a rather specific thermodynamic perspective. In this article I point out that if one wishes to reformulate classical Newtonian gravity in terms of an entropic force, then the fact that Newtonian gravity is described by a conservative force places significant constraints on the form of the entropy and temperature functions. (These constraints also apply to entropic reinterpretations of electromagnetism, and indeed to any conservative force derivable from a potential.) The constraints I will establish are sufficient to present real and significant problems for any reasonable variant of Verlinde's entropic gravity proposal, though for technical reasons the constraints established herein do not directly impact on either Jacobson's or Padmanabhan's versions of entropic gravity. In an attempt to resolve these issues, I will extend the usual notion of entropic...

  11. Causal reasoning with forces.

    Science.gov (United States)

    Wolff, Phillip; Barbey, Aron K

    2015-01-01

    Causal composition allows people to generate new causal relations by combining existing causal knowledge. We introduce a new computational model of such reasoning, the force theory, which holds that people compose causal relations by simulating the processes that join forces in the world, and compare this theory with the mental model theory (Khemlani et al., 2014) and the causal model theory (Sloman et al., 2009), which explain causal composition on the basis of mental models and structural equations, respectively. In one experiment, the force theory was uniquely able to account for people's ability to compose causal relationships from complex animations of real-world events. In three additional experiments, the force theory did as well as or better than the other two theories in explaining the causal compositions people generated from linguistically presented causal relations. Implications for causal learning and the hierarchical structure of causal knowledge are discussed. PMID:25653611

  12. Optical force stamping lithography

    OpenAIRE

    Nedev, Spas; Urban, Alexander S.; Lutich, Andrey A.; Feldmann, Jochen

    2011-01-01

    Here we introduce a new paradigm of far-field optical lithography, optical force stamping lithography. The approach employs optical forces exerted by a spatially modulated light field on colloidal nanoparticles to rapidly stamp large arbitrary patterns comprised of single nanoparticles onto a substrate with a single-nanoparticle positioning accuracy well beyond the diffraction limit. Because the process is all-optical, the stamping pattern can be changed almost instantly and there is no const...

  13. Ground water in Creek County, Oklahoma

    Science.gov (United States)

    Cady, Richard Carlysle

    1937-01-01

    Creek County has been designated as a problem area by the Land Use Planning Section of the Resettlement Administration. Some of the earliest oil fields to brought into production were situated in and near this county, and new fields have been opened from time to time during the ensuing years. The production of the newer fields, however, has not kept pace with the exhaustion of the older fields, and the county now presents an excellent picture of the problems involved in adjusting a population to lands that are nearly depleted of their mineral wealth. Values of land have been greatly depressed; tax collection is far in arrears; tenancy is widespread; and in addition more people will apparently be forced to depend on the income from agriculture than the land seems capable of supporting. The county as a whole is at best indifferently suitable for general farming. The Land Use planning Section proposes to study the present and seemingly immanent maladjustments of population to the resources of the land, and make recommendations for their correction. The writer was detailed to the Land Use Planning Section of Region VIII for the purposes of making studies of ground water problems in the region. In Creek County two investigations were made. In September, 1936, the writer spent about ten days investigating the availability of ground water for the irrigation of garden crops during drouths. If it proved feasible to do this generally throughout the county, the Land Use Planning Section might be able to encourage this practice. The second investigation made by the writer was in regard to the extent to which ground water supplies have been damaged by oil well brines. He was in county for four days late in January 1937, and again in March, 1937. During part of the second field trip he was accompanied by R.M. Dixon, sanitary engineer of the Water Utilization Unit of the Resettlement Administration. (available as photostat copy only)

  14. Optical ``Bernoulli'' forces

    Science.gov (United States)

    Movassagh, Ramis; Johnson, Steven

    2015-03-01

    By Bernoulli's law, an increase in the relative speed of a fluid around a body is accompanies by a decrease in the pressure. Therefore, a rotating body in a fluid stream experiences a force perpendicular to the motion of the fluid because of the unequal relative speed of the fluid across its surface. It is well known that light has a constant speed irrespective of the relative motion. Does a rotating body immersed in a stream of photons experience a Bernoulli-like force? We show that, indeed, a rotating dielectric cylinder experiences such a lateral force from an electromagnetic wave. In fact, the sign of the lateral force is the same as that of the fluid-mechanical analogue as long as the electric susceptibility is positive (? >?0), but for negative-susceptibility materials (e.g. metals) we show that the lateral force is in the opposite direction. Because these results are derived from a classical electromagnetic scattering problem, Mie-resonance enhancements that occur in other scattering phenomena also enhance the lateral force. [This talk is based on Phys. Rev. A 88, 023829 (2013).] Supported in part by the U.S. Army Research Office under contract W911NF-13-D-0001.

  15. Nonlinear vibration isolator with adjustable restoring force

    Science.gov (United States)

    Araki, Yoshikazu; Asai, Takehiko; Kimura, Kosuke; Maezawa, Kosei; Masui, Takeshi

    2013-11-01

    This paper presents a vertical quasi-zero stiffness (QZS) vibration isolator with a mechanism for adjusting restoring force. QZS vibration isolators have high initial stiffness and QZS around the static equilibrium position. This way, excessive deformation due to self-weight can be avoided while having enough vibration reduction capability to dynamic excitations. One of the main issues left for QZS vibration isolators is the difficulty in keeping the vibration reduction capability when the vibration isolated object is replaced. In such a case, adjustment of its restoring force becomes necessary in accordance with the self-weight of the newly placed vibration isolated object. This paper attempts to address this issue by proposing a mechanism that enables quick and easy adjustment of the restoring force of a QZS vibration isolator. The proposed mechanism consists of cranks and a screw jack. With the present mechanism, the restoring force provided by horizontally placed springs can be converted into the vertical restoring force of the vibration isolator. In the conversion, the vertical resisting force can be adjusted simply by applying and removing torque to the screw jack to change and hold the angle of inclined bars placed in the cranks. In this study, a prototype of a class of QZS vibration isolator having the proposed mechanism is produced. Shaking table tests are performed to demonstrate the efficacy of the present mechanism, where the produced prototype is subjected to various sinusoidal and earthquake ground motions. It is demonstrated through the shaking table tests that the produced prototype can reduce the response acceleration within the same tolerance even when the mass of the vibration isolated object is changed.

  16. Physics investigate the forces of nature

    CERN Document Server

    Gardner, Jane P

    2014-01-01

    Have you ever noticed that the physical world works in certain ways? When you push an object it moves. Skateboarders use force and motion to perform tricks. If you jump up as high as you can, you''ll quickly fall back to the ground. Baseball players use gravity to bring the ball back down when they throw it. When you flip a switch, electricity powers your toaster. Rock bands use electricity to put on a show. The fascinating science of physics helps you understand why forces, motion, gravity, electricity, light, and sound work in predictable ways.Combining inquiry-based, age-appropriate activities with physics topics, Physics: Investigate the Forces of Nature features graphic novel illustrations, fascinating sidebars, youtube links, and a glossary of important vocabulary to illuminate the complex world of physics and bring it to life. Projects include designing a skateboard park that maps the forces at work on the skateboarder and the skateboard, arguing your way out of a speeding ticket using the properties o...

  17. Lenz's Law: Feel the Force.

    Science.gov (United States)

    Sawicki, Charles A.

    1996-01-01

    Describes a simple, inexpensive system that allows students to have hands-on contact with simple experiments involving forces generated by induced currents. Discusses the use of a dynamic force sensor in making quantitative measurements of the forces generated. (JRH)

  18. Ab initio long-range interaction and adiabatic channel capture model for ultracold reactions between the KRb molecules

    Science.gov (United States)

    Buchachenko, A. A.; Stolyarov, A. V.; Szcz??niak, M. M.; Cha?asi?ski, G.

    2012-09-01

    The coefficients at the lowest-order electrostatic, induction, and dispersion terms of the anisotropic long-range potential between the two KRb(1?+) molecules are evaluated through the static and dynamic molecular properties using the ab initio coupled cluster techniques. Adiabatic channel potentials for the ground-state molecules are obtained and used for the numerical quantum capture probability calculations in the spirit of the statistical adiabatic channel models. Capture rate coefficients for indistinguishable (polarized) and distinguishable (unpolarized) molecules at temperatures below 10 ?K agree well with those computed with the simple isotropic dispersion R-6 potential, but underestimate the measured ones [Ospelkaus et al., Science 327, 853 (2010), 10.1126/science.1184121] up to a factor of 3. Preliminary assessment of the effects of higher-order long-range terms, retardation of dispersion forces, and magnetic dipole-dipole interaction does not offer any clear perspectives for drastic improvement of the capture approximation for the reactions studied.

  19. Working Through Preconception: Moving from Forcing to Emergence

    Directory of Open Access Journals (Sweden)

    Kim Kwok

    2012-12-01

    Full Text Available Much has been written about grounded theory and the processes of theory generation. Less is written about managing the problem of preconception, which has the potential to undermine the openness and emergence that are fundamental to classic grounded theory. The purpose of this paper is to discuss the practical realities of managing preconception, and to draw attention to less well recognised factors that contribute to forcing. The topic interest, tactical innovation in rugby, is introduced. Researcher motivation and the management of preconception are discussed. The example used is the theory of developing, which explains how rugby coaches in New Zealand manage the problem of winning games. The research demonstrates how the novice grounded theory researcher who is prepared to follow the method and trust the process can produce a rigorous grounded theory that makes a meaningful contribution to rugby coaches, players and their administrators.

  20. Confusion around the tidal force and the centrifugal force

    CERN Document Server

    Matsuda, Takuya; Boffin, Henri M J

    2015-01-01

    We discuss the tidal force, whose notion is sometimes misunderstood in the public domain literature. We discuss the tidal force exerted by a secondary point mass on an extended primary body such as the Earth. The tidal force arises because the gravitational force exerted on the extended body by the secondary mass is not uniform across the primary. In the derivation of the tidal force, the non-uniformity of the gravity is essential, and inertial forces such as the centrifugal force are not needed. Nevertheless, it is often asserted that the tidal force can be explained by the centrifugal force. If we literally take into account the centrifugal force, it would mislead us. We therefore also discuss the proper treatment of the centrifugal force.

  1. Separable Optical Potentials for (d,p) Reactions

    CERN Document Server

    Elster, Ch; Eremenko, V; Nunes, F M; Arbanas, G; Escher, J E; Thompson, I J

    2014-01-01

    An important ingredient for applications of nuclear physics to e.g. astrophysics or nuclear energy are the cross sections for reactions of neutrons with rare isotopes. Since direct measurements are often not possible, indirect methods like (d,p) reactions must be used instead. Those (d,p) reactions may be viewed as effective three-body reactions and described with Faddeev techniques. An additional challenge posed by (d,p) reactions involving heavier nuclei is the treatment of the Coulomb force. To avoid numerical complications in dealing with the screening of the Coulomb force, recently a new approach using the Coulomb distorted basis in momentum space was suggested. In order to implement this suggestion, one needs not only to derive a separable representation of neutron- and proton-nucleus optical potentials, but also compute the Coulomb distorted form factors in this basis.

  2. Incomplete fusion reactions

    International Nuclear Information System (INIS)

    Various aspects of the mechanism of heavy-ion induced reactions in the range of bombarding energies from a few to about 20 MeV/A are reviewed with special emphasis on the reactions for very asymmetric systems. Results of the experimental studies of binary reactions and particularly of the incomplete fusion reactions (selected by means of various coincidence techniques)are discussed. A model of generalized critical angular momentum is formulated. The model explains essential features of the incomplete fusion reactions and predicts that particular reaction channels are localized in well defined regions of angular momenta. An extension of this model (the sum-rule model) is also proposed in attempt to consistently describe the complete fusion reactions, incomplete fusion reactions and multibody reactions in the framework of statistical competition constrained by the angular momentum limitations. (author)

  3. Ground Control System Description Document

    International Nuclear Information System (INIS)

    The Ground Control System contributes to the safe construction and operation of the subsurface facility, including accesses and waste emplacement drifts, by maintaining the configuration and stability of the openings during construction, development, emplacement, and caretaker modes for the duration of preclosure repository life. The Ground Control System consists of ground support structures installed within the subsurface excavated openings, any reinforcement made to the rock surrounding the opening, and inverts if designed as an integral part of the system. The Ground Control System maintains stability for the range of geologic conditions expected at the repository and for all expected loading conditions, including in situ rock, construction, operation, thermal, and seismic loads. The system maintains the size and geometry of operating envelopes for all openings, including alcoves, accesses, and emplacement drifts. The system provides for the installation and operation of sensors and equipment for any required inspection and monitoring. In addition, the Ground Control System provides protection against rockfall for all subsurface personnel, equipment, and the engineered barrier system, including the waste package during the preclosure period. The Ground Control System uses materials that are sufficiently maintainable and that retain the necessary engineering properties for the anticipated conditions of the preclosure service life. These materials are also compatible with postclosure waste isolation performance requirements of the repository. The Ground Control System interfaces with the Subsurface Facility System for operating envelopes, drift orientation, and excavated opening dimensions, Emplacement Drift System for material compatibility, Monitored Geologic Repository Operations Monitoring and Control System for ground control instrument readings, Waste Emplacement/Retrieval System to support waste emplacement operations, and the Subsurface Excavation System for ground control installation

  4. Analytical expression of mean force in quantum molecular dynamics

    International Nuclear Information System (INIS)

    The nuclear mean field is very important in the intermediate and high energy nuclear reactions. The field is constructed by the interaction of nucleons in the nucleus and acts on each nucleons. the movement of nucleons obeys the Newton equation. It is important to improve the method of solving Newton differential equations and reduce the calculation of potentials. This can be realized by introducing the analytical forces instead of the potential difference. The analytical force expressions have been put into the code INENRKS. The application of the analytical force expression not only save much CPU time but also raise the calculation accuracy. (3 tabs.)

  5. The calibration of sub-Coulomb heavy ion proton transfer reactions

    International Nuclear Information System (INIS)

    Measurements were made of the cross sections for the 27Al(16O,15N)28Si, 89Y(15N,16O)88Sr and 89Y(27Al,28Si)88Sr reactions at energies near and below the Coulomb barrier. The first reaction required separate measurements of the transfer to elastic cross section ratio for particular charge states, the charge state distribution for 27Al and 28Si ions, and the absolute elastic scattering cross section for the 27Al + 16O system. The ratio measurement required the combined use of two relatively new scientific instruments: the momentum filter and the Bragg curve spectrometer. The latter two transfer measurements were performed using the same setup involving surface barrier detectors at backward angles. Additional elastic scattering data for the 15N + 28Si, 89Y + 15N, 89Sr + 27Al, and 88Sr + 28Si systems was collected to provide entrance and exit channel parameters needed for the theoretical calculations of the transfer reaction cross sections. The calculations were made using the DWBA code, LOLA, which assumes a one-step direct reaction mechanism. A correction was made to the code to properly include the effects of the spin-orbit force in the proton binding potentials. The original goal of these measurements was to combine the three normalization factors to determine the ground state proton spectroscopic factors for 16O, 28Si and 89Y. Such an analysis was found to yield a spectroscopic factor which significantly exceeded the shell model limit in the case of 16O. It is possible that the inclusion of multi-step processes may resolve this disagreement. 36 refs., 109 figs., 21 tabs

  6. Chemical reaction between single hydrogen atom and graphene

    International Nuclear Information System (INIS)

    We study chemical reaction between a single hydrogen atom and a graphene, which is the elemental reaction between hydrogen and graphitic carbon materials. In the present work, classical molecular dynamics simulation is used with modified Brenner's empirical bond order potential. The three reactions, that is, absorption reaction, reflection reaction and penetration reaction, are observed in our simulation. Reaction rates depend on the incident energy of the hydrogen atom and the graphene temperature. The dependence can be explained by the following mechanisms: (1) The hydrogen atom receives repulsive force by ?-electrons in addition to nuclear repulsion. (2) Absorbing the hydrogen atom, the graphene transforms its structure to the 'overhand' configuration such as sp3 state. (3) The hexagonal hole of the graphene is expanded during the penetration of the hydrogen atom. (author)

  7. Chemical Reaction between Single Hydrogen Atom and Graphene

    CERN Document Server

    Ito, A; Takayama, A; Ito, Atsushi; Nakamura, Hiroaki; Takayama, Arimichi

    2007-01-01

    We study chemical reaction between a single hydrogen atom and a graphene, which is the elemental reaction between hydrogen and graphitic carbon materials. In the present work, classical molecular dynamics simulation is used with modified Brenner's empirical bond order potential. The three reactions, that is, absorption reaction, reflection reaction and penetration reaction, are observed in our simulation. Reaction rates depend on the incident energy of the hydrogen atom and the graphene temperature. The dependence can be explained by the following mechanisms: (1) The hydrogen atom receives repulsive force by pi-electrons in addition to nuclear repulsion. (2) Absorbing the hydrogen atom, the graphene transforms its structure to the ``overhang'' configuration such as sp-3 state. (3) The hexagonal hole of the graphene is expanded during the penetration of the hydrogen atom.

  8. Radiative Forcing of Climate Change

    Energy Technology Data Exchange (ETDEWEB)

    Ramaswamy, V.; Boucher, Olivier; Haigh, J.; Hauglustaine, D.; Haywood, J.; Myhre, G.; Nakajima, Takahito; Shi, Guangyu; Solomon, S.; Betts, Robert E.; Charlson, R.; Chuang, C. C.; Daniel, J. S.; Del Genio, Anthony D.; Feichter, J.; Fuglestvedt, J.; Forster, P. M.; Ghan, Steven J.; Jones, A.; Kiehl, J. T.; Koch, D.; Land, C.; Lean, J.; Lohmann, Ulrike; Minschwaner, K.; Penner, Joyce E.; Roberts, D. L.; Rodhe, H.; Roelofs, G.-J.; Rotstayn, Leon D.; Schneider, T. L.; Schumann, U.; Schwartz, Stephen E.; Schwartzkopf, M. D.; Shine, K. P.; Smith, Steven J.; Stevenson, D. S.; Stordal, F.; Tegen, I.; van Dorland, R.; Zhang, Y.; Srinivasan, J.; Joos, Fortunat

    2001-10-01

    Chapter 6 of the IPCC Third Assessment Report Climate Change 2001: The Scientific Basis. Sections include: Executive Summary 6.1 Radiative Forcing 6.2 Forcing-Response Relationship 6.3 Well-Mixed Greenhouse Gases 6.4 Stratospheric Ozone 6.5 Radiative Forcing By Tropospheric Ozone 6.6 Indirect Forcings due to Chemistry 6.7 The Direct Radiative Forcing of Tropospheric Aerosols 6.8 The Indirect Radiative Forcing of Tropospheric Aerosols 6.9 Stratospheric Aerosols 6.10 Land-use Change (Surface Albedo Effect) 6.11 Solar Forcing of Climate 6.12 Global Warming Potentials hydrocarbons 6.13 Global Mean Radiative Forcings 6.14 The Geographical Distribution of the Radiative Forcings 6.15 Time Evolution of Radiative Forcings Appendix 6.1 Elements of Radiative Forcing Concept References.

  9. Radiative forcing by contrails

    Directory of Open Access Journals (Sweden)

    R. Meerkötter

    Full Text Available A parametric study of the instantaneous radiative impact of contrails is presented using three different radiative transfer models for a series of model atmospheres and cloud parameters. Contrails are treated as geometrically and optically thin plane parallel homogeneous cirrus layers in a static atmosphere. The ice water content is varied as a function of ambient temperature. The model atmospheres include tropical, mid-latitude, and subarctic summer and winter atmospheres. Optically thin contrails cause a positive net forcing at top of the atmosphere. At the surface the radiative forcing is negative during daytime. The forcing increases with the optical depth and the amount of contrail cover. At the top of the atmosphere, a mean contrail cover of 0.1% with average optical depth of 0.2 to 0.5 causes about 0.01 to 0.03 Wm-2 daily mean instantaneous radiative forcing. Contrails cool the surface during the day and heat the surface during the night, and hence reduce the daily temperature amplitude. The net effect depends strongly on the daily variation of contrail cloud cover. The indirect radiative forcing due to particle changes in natural cirrus clouds may be of the same magnitude as the direct one due to additional cover.

    Key words. Atmospheric composition and structure (aerosols and particles · Meteorology and atmospheric dynamics (climatology · radiative processes

  10. Radiative forcing by contrails

    Energy Technology Data Exchange (ETDEWEB)

    Meerkoetter, R.; Schumann, U. [DLR Oberpfaffenhofen, Wessling (Germany). Inst. fuer Phys. der Atmosphaere; Doelling, D.R.; Minnis, P. [National Aeronautics and Space Administration, Hampton, VA (United States). Langley Research Center; Nakajima, T.; Tsushima, Y. [Tokyo Univ. (Japan). Center for Climate System Research

    1999-08-01

    A parametric study of the instantaneous radiative impact of contrails is presented using three different radiative transfer models for a series of model atmospheres and cloud parameters. Contrails are treated as geometrically and optically thin plane parallel homogeneous cirrus layers in a static atmosphere. The ice water content is varied as a function of ambient temperature. The model atmospheres include tropical, midlatitude, and subarctic summer and winter atmospheres. Optically thin contrails cause a positive net forcing at top of the atmosphere. At the surface the radiative forcing is negative during daytime. The forcing increases with the optical depth and the amount of contrail cover. At the top of the atmosphere, a mean contrail cover of 0.1% with average optical depth of 0.2 to 0.5 causes about 0.01 to 0.03 Wm{sup -2} daily mean instantaneous radiative forcing. Contrails cool the surface during the day and heat the surface during the night, and hence reduce the daily temperature amplitude. The net effect depends strongly on the daily variation of contrail cloud cover. The indirect radiative forcing due to particle changes in natural cirrus clouds may be of the same magnitude as the direct one due to additional cover. (orig.) 78 refs.

  11. Chiral drag force

    CERN Document Server

    Rajagopal, Krishna

    2015-01-01

    We provide a holographic evaluation of novel contributions to the drag force acting on a heavy quark moving through strongly interacting plasma. The new contributions are chiral in that they act in opposite directions in plasmas containing an excess of left- or right-handed quarks and in that they are proportional to the coefficient of the axial anomaly. These new contributions to the drag force act either parallel to or antiparallel to an external magnetic field or to the vorticity of the fluid plasma. In all these respects, these contributions to the drag force felt by a heavy quark are analogous to the chiral magnetic effect on light quarks. However, the new contribution to the drag force is independent of the electric charge of the heavy quark and is the same for heavy quarks and antiquarks. We show that although the chiral drag force can be non-vanishing for heavy quarks that are at rest in the local fluid rest frame, it does vanish for heavy quarks that are at rest in a frame in which there is no local ...

  12. Asymmetric Electrostatic Force

    Directory of Open Access Journals (Sweden)

    Katsuo Sakai

    2014-09-01

    Full Text Available Asymmetric electrostatic forces are a very interesting and new phenomenon. The magnitude of an electrostatic force that acts on a point charge does not change when the direction of the electric field is reversed. On the contrary, the magnitude of the electrostatic force that acts on a charged asymmetric shaped conductor does change when the direction of the electric field is reversed. 5 years ago, this phenomenon was reported by a simple experiment and a simulation and named as an Asymmetric electrostatic force unofficially by the author. After that, several simulations confirmed this phenomenon. However, several experiments did not yet confirm it clearly. The difference between the simulations and the experiments depends upon differences of their conditions. The simulations had been done under ideal (perfect conditions; the experiments, on the contrary, had been done under actual (not perfect conditions. In the new experiment, its conditions were improved to near ideal (perfect conditions. As a result the existence of the Asymmetric electrostatic force was more clearly confirmed.

  13. Impacts of Rotational Ground Motions on Structural Systems

    Science.gov (United States)

    Kalkan, E.; Graizer, V.

    2008-12-01

    Current engineering practice establishes seismic demands based on horizontal component of ground motion; rotational (tilting) and vertical components are almost always neglected. However, ground rotations can be significant in the near-field zone. For example, tilt reached more than 3 degrees at the Pacoima Dam upper left abutment during the 1994 Northridge Earthquake. Coupling of rotational and translational components of ground motion may impose amplified seismic demands on structures. To consider these enhanced demands in design and performance assessment, governing equation of motion for multi-component (horizontal, vertical, and rotational) excitation is presented. The expanded equation includes an additional overturning moment at the base of the inverted oscillator created by gravitational acceleration on the oscillator's mass when it is displaced from its original position. This effect called P-Delta in engineering is originated by ground tilting and vertical acceleration in addition to inertia forces due to angular and horizontal accelerations. Using an idealized model of a bridge bent, inelastic structural response parameters are computed considering single and multi-component excitation; and it is demonstrated that higher ductility demand may ensue when vertical and rotational components are coupled with horizontal component. Ignoring this coupling may lead to significant underestimation of seismic demands produced by earthquake ground shaking.

  14. Nuclear structure and pion reactions

    Energy Technology Data Exchange (ETDEWEB)

    Hayes, A.C.

    1989-01-01

    Shell model analyses of inelastic pion and electron scattering are used to derive many body wave functions suitable for DCX studies of masses 14 and 18. These calculations show clear evidence for the need to include core-excitations in the wave functions of the ground and excited states of these nuclei. The appropriate enhancement and quenching of the isoscalar and isovector one-body density matrix elements are deduced, and their possible effects on DCX cross-sections discussed. Effective (q-dependent) transitions, obtained from microscopic core-polarization calculations, are found to give an excellent description of the pion angular distributions and {pi}{sup {plus}}/{pi}{sup {minus}} ratios in this mass region, justifying the use of effective charges in shell model studies of pion reactions. 13 refs., 12 figs.

  15. Ground Enterprise Management System Project

    National Aeronautics and Space Administration — Spacecraft ground systems are on the cusp of achieving "plug-and-play" capability, i.e., they are approaching the state in which the various components can be...

  16. Ground Water and Climate Change

    Science.gov (United States)

    Taylor, Richard G.; Scanlon, Bridget; Doell, Petra; Rodell, Matt; van Beek, Rens; Wada, Yoshihide; Longuevergne, Laurent; Leblanc, Marc; Famiglietti, James S.; Edmunds, Mike; Konikow, Leonard; Green, Timothy R.; Chen, Jianyao; Taniguchi, Makoto; Bierkens, Marc F. P.; MacDonald, Alan; Fan, Ying; Maxwell, Reed M.; Yechieli, Yossi; Gurdak, Jason J.; Allen, Diana M.; Shamsudduha, Mohammad; Hiscock, Kevin; Yeh, Pat J. -F; Holman, Ian; Treidel, Holger

    2013-01-01

    As the world's largest distributed store of fresh water, ground water plays a central part in sustaining ecosystems and enabling human adaptation to climate variability and change. The strategic importance of ground water for global water and food security will probably intensify under climate change as more frequent and intense climate extremes (droughts and floods) increase variability in precipitation, soil moisture and surface water. Here we critically review recent research assessing the impacts of climate on ground water through natural and human-induced processes as well as through groundwater-driven feedbacks on the climate system. Furthermore, we examine the possible opportunities and challenges of using and sustaining groundwater resources in climate adaptation strategies, and highlight the lack of groundwater observations, which, at present, limits our understanding of the dynamic relationship between ground water and climate.

  17. Humic substances in ground waters

    International Nuclear Information System (INIS)

    The presence of naturally occurring complexing agents that may enhance the migration of disposed radionuclikes and thus facilitate their uptake by plantsis a problem associated with the underground disposal of radioactive wastes in bedrock. The main purpose of this work is to characterized humic substances from ground water and compare them with humic substances from surface water. The humic materials isolated from ground waters of a borehole in Fjaellveden (Sweden) were characterized by elemental and functional group analyses. Spectroscopic properties, molecular weight distributions as well as acid-base properties of the fulvic and humic fractions were also studied. The ground water humic substances were found to be quite similar in many respects (but not identical) to the Swedish surface water humics concentrated from the Goeta River but appeared to be quite different from the American ground water humics from Biscayne Florida Aquifer or Laramie Fox-Hills in Colorado. The physico-chemical properties of the isolated humic materials are discussed

  18. The Modifiability of Grounded Theory

    Directory of Open Access Journals (Sweden)

    Alvita K. Nathaniel, Ph.D., RN

    2010-02-01

    Full Text Available Grounded theories are powerful tools that fit empirical situations and provide “relevant predictions, explanations, interpretations, and applications” (Glaser & Strauss, 1967, p.1. Because of their real-world orientation, grounded theories are particularly appropriate for health care research. They can help professionals understand that certain patterns always seem to emerge, that particular people respond in predictable ways, and that actions produce predictable results (Nathaniel & Andrews, 2007. When physicians and nurses better understand patterns that affect patients, they can work towards altering harmful patterns to improve the quality of patient care. As time passes, one may ask, when do grounded theories become obsolete? When are they no longer useful? The purpose of this paper is to revisit the seminal grounded theory, Awareness of Dying, and compare it to contemporary conceptual and descriptive research on end-of-life care, asking the question, is the theory in need of modification?

  19. The infrared driven cis-trans isomerization reaction of nitrous acid (HONO) and energy transport in peptide helices

    OpenAIRE

    Botan, V.

    2008-01-01

    This thesis contains the results of two distinct scientific inquiries. The first part investigates a model system for ground state chemical reactions whereas the second part examines the energy transport in peptide helices. The cis-trans isomerization of nitrous acid (HONO) in solid matrices is a model system of a chemical reaction in the electronic ground state. The isomerization reaction is reversible and can be triggered by the photo-excitation of the OH stretch. Exciting OHcis in an IR...

  20. How Insensitive: Principles, Facts and Normative Grounds in Cohen’s Critique of Rawls

    OpenAIRE

    Daniel Kofman

    2012-01-01

    Cohen’s hostility to Rawls’ justification of the Difference Principle by social facts spawned Cohen’s general thesis that ultimate principles of justice and morality are fact-insensitive, but explain how any fact-sensitive principle is grounded in facts. When facts F ground principle P, reformulating this relation as conditional “If F, then P” is trivial and thus explanatorily impotent. Explanatory, hence justificatory, force derives either from subsumption under more general princi...

  1. Forces in strategy formation

    DEFF Research Database (Denmark)

    Steensen, Elmer Fly; Sanchez, Ron

    2008-01-01

    This chapter proposes that organizational strategy formation should be characterized theoretically as a process that is subject to several interacting forces, rather than represented by separate discrete decisionmodels or theoretic perspectives, as is commonly done in the strategic management literature. Based on an extensive review of relevant theory and empirical work in strategic decision-making, organizational change theory, cognitive and social psychology, and strategy processes, seven kinds of ''forces'' - rational, imposed, teleological, learning, political, heuristic, and social - are identified as interacting in and having significant influence on the strategy formation process. It is further argued that by applying a holistic ''forces-view'' of the significant and interacting influences on strategy formation, we can better understand the dynamics and challenges in managing the process of defining and changing organizational strategies.

  2. Parametrically forced pattern formation.

    Science.gov (United States)

    Armbruster, Dieter; George, Marguerite; Oprea, Iuliana

    2001-03-01

    Pattern formation in a nonlinear damped Mathieu-type partial differential equation defined on one space variable is analyzed. A bifurcation analysis of an averaged equation is performed and compared to full numerical simulations. Parametric resonance leads to periodically varying patterns whose spatial structure is determined by amplitude and detuning of the periodic forcing. At onset, patterns appear subcritically and attractor crowding is observed for large detuning. The evolution of patterns under the increase of the forcing amplitude is studied. It is found that spatially homogeneous and temporally periodic solutions occur for all detuning at a certain amplitude of the forcing. Although the system is dissipative, spatial solitons are found representing domain walls creating a phase jump of the solutions. Qualitative comparisons with experiments in vertically vibrating granular media are made. (c) 2001 American Institute of Physics. PMID:12779440

  3. Evaluation of multimodal ground cues

    DEFF Research Database (Denmark)

    Nordahl, Rolf; Lecuyer, Anatole

    2012-01-01

    This chapter presents an array of results on the perception of ground surfaces via multiple sensory modalities,with special attention to non visual perceptual cues, notably those arising from audition and haptics, as well as interactions between them. It also reviews approaches to combining synthetic multimodal cues, from vision, haptics, and audition, in order to realize virtual experiences of walking on simulated ground surfaces or other features.

  4. The Modifiability of Grounded Theory

    OpenAIRE

    Alvita K Nathaniel, Ph D.; Tom Andrews, B. Sc

    2010-01-01

    Grounded theories are powerful tools that fit empirical situations and provide “relevant predictions, explanations, interpretations, and applications” (Glaser & Strauss, 1967, p.1). Because of their real-world orientation, grounded theories are particularly appropriate for health care research. They can help professionals understand that certain patterns always seem to emerge, that particular people respond in predictable ways, and that actions produce predictable results (Nathaniel & And...

  5. Insights into the mechanisms on chemical reactions: reaction paths for chemical reactions

    International Nuclear Information System (INIS)

    We report reaction paths for two prototypical chemical reactions: Li + HF, an electron transfer reaction, and OH + H2, an abstraction reaction. In the first reaction we consider the connection between the energetic terms in the reaction path Hamiltonian and the electronic changes which occur upon reaction. In the second reaction we consider the treatment of vibrational effects in chemical reactions in the reaction path formalism. 30 refs., 9 figs

  6. Microscale Thermite Reactions.

    Science.gov (United States)

    Arnaiz, Francisco J.; Aguado, Rafael; Arnaiz, Susana

    1998-01-01

    Describes the adaptation of thermite (aluminum with metal oxides) reactions from whole-class demonstrations to student-run micro-reactions. Lists detailed directions and possible variations of the experiment. (WRM)

  7. Preequilibrium Nuclear Reactions

    International Nuclear Information System (INIS)

    After a survey on existing experimental data on precompound reactions and a description of preequilibrium reactions, theoretical models and quantum mechanical theories of preequilibrium emission are presented. The 25 papers of this meeting are analyzed separately

  8. Treatment and Managing Reactions

    Science.gov (United States)

    ... Diet Unproven Diagnostic Tests Treatment & Managing Reactions Epinephrine Auto-injectors Advancing a Cure Living with Food Allergies Tips ... Diet Unproven Diagnostic Tests Treatment & Managing Reactions Epinephrine Auto-injectors Advancing a Cure Living with Food Allergies Tips ...

  9. Microfluidic chemical reaction circuits

    Science.gov (United States)

    Lee, Chung-cheng (Irvine, CA); Sui, Guodong (Los Angeles, CA); Elizarov, Arkadij (Valley Village, CA); Kolb, Hartmuth C. (Playa del Rey, CA); Huang, Jiang (San Jose, CA); Heath, James R. (South Pasadena, CA); Phelps, Michael E. (Los Angeles, CA); Quake, Stephen R. (Stanford, CA); Tseng, Hsian-rong (Los Angeles, CA); Wyatt, Paul (Tipperary, IE); Daridon, Antoine (Mont-Sur-Rolle, CH)

    2012-06-26

    New microfluidic devices, useful for carrying out chemical reactions, are provided. The devices are adapted for on-chip solvent exchange, chemical processes requiring multiple chemical reactions, and rapid concentration of reagents.

  10. Universalities in ultracold reactions of alkali polar molecules

    OpenAIRE

    Que?me?ner, Goulven; Bohn, John L.; Petrov, Alexander; Kotochigova, Svetlana

    2011-01-01

    We consider ultracold collisions of ground-state, heteronuclear alkali dimers that are susceptible to four-center chemical reactions 2 AB -> A2 + B2 even at sub-microKelvin temperature. These reactions depend strongly on species, temperature, electric field, and confinement in an optical lattice. We calculate ab initio van der Walls coefficients for these interactions, and use a quantum formalism to study the scattering properties of such molecules under an external electric...

  11. Suppression of excited-state contributions to stellar reaction rates

    OpenAIRE

    Rauscher, T

    2013-01-01

    It has been shown in previous work [Phys. Rev. Lett. 101, 191101 (2008); Phys. Rev. C 80, 035801 (2009)] that a suppression of the stellar enhancement factor (SEF) occurs in some endothermic reactions at and far from stability. This effect is re-evaluated using the ground-state contributions to the stellar reaction rates, which were shown to be better suited to judge the importance of excited state contributions than the previously applied SEFs. An update of the tables shown...

  12. Flexible Impact Force Sensor

    OpenAIRE

    Chen Liu; Yukio Fujimoto; Yoshikazu Tanaka

    2014-01-01

    When human body is punched by boxing glove, both body surface and boxing glove deform in a complex shape. The purpose of this study is to develop a flexible sensor that can be used in such interface. Firstly, several mechanical phenomena, which are the cause of the error signal of the sensor, are discussed. These are the influences of out-of-plane bending deformation, shear force caused by rubbing, shear force caused by the Poisson’s effect of contact material, and the lateral compressiv...

  13. Optical Bernoulli forces

    OpenAIRE

    Movassagh, Ramis; Johnson, Steven G.

    2013-01-01

    By Bernoulli's law, an increase in the relative speed of a fluid around a body is accompanies by a decrease in the pressure. Therefore, a rotating body in a fluid stream experiences a force perpendicular to the motion of the fluid because of the unequal relative speed of the fluid across its surface. It is well known that light has a constant speed irrespective of the relative motion. Does a rotating body immersed in a stream of photons experience a Bernoulli-like force? We ...

  14. GENERIC framework for reaction diffusion systems

    OpenAIRE

    Hoyuelos, Miguel

    2012-01-01

    The GENERIC theory provides a framework for the description of non-equilibrium phenomena in isolated systems beyond local thermal equilibrium and beyond linear non-equilibrium (i.e., linear relations between thermodynamic forces and currents). The framework is applied to some simple and general systems: reactions with detailed balance and Fokker-Planck (FP) equation. It is shown how to apply the theory to a combination of system and reservoir in the case of the FP equation.

  15. Phenomenology of neutrino reactions

    International Nuclear Information System (INIS)

    A review of neutrino reactions is given with sections devoted to the following topics: scattering of neutrinos by electrons; scattering of neutrinos by nucleons, exclusive reactions; scattering of neutrinos by nucleons, inclusive and semi-inclusive reactions; neutrinos and partons. (7 figures, 57 references) (SDF)

  16. Resonant thermonuclear reaction rate

    International Nuclear Information System (INIS)

    Basic physical principles for the resonant and nonresonant thermonuclear reaction rates are applied to find their standard representations for nuclear astrophysics. Closed-form representations for the resonant reaction rate are derived in terms of Meijer's G-function. Analytic representations of the resonant and nonresonant nuclear reaction rates are compared and the appearance of Meijer's G-function is discussed in physical terms

  17. Anaphylactoid reactions to paracetamol

    OpenAIRE

    Ayonrinde, O.; Saker, B.

    2000-01-01

    The toxic effects of paracetamol in overdose quantities are well recognised but the occurrence of anaphylactoid reactions to paracetamol is infrequently identified by consumers and health care professionals. Nevertheless adverse reactions to this drug, even in therapeutic doses, can have fatal or near fatal consequences. A case of an anaphylactoid reaction to paracetamol is described.???Keywords: paracetamol; anaphylaxis; allergy; hypersensitivity

  18. Guidelines on radon measurements in building grounds

    International Nuclear Information System (INIS)

    These Guidelines on radon measurements in building grounds were issued by the State Institute of Radiation Hygiene. They recommend maximum permissible average yearly radon concentrations in building grounds

  19. Reaction coordinates for electron transfer reactions

    International Nuclear Information System (INIS)

    The polarization fluctuation and energy gap formulations of the reaction coordinate for outer sphere electron transfer are linearly related to the constant energy constraint Lagrangian multiplier m in Marcus' theory of electron transfer. The quadratic dependence of the free energies of the reactant and product intermediates on m and m+1, respectively, leads to similar dependence of the free energies on the reaction coordinates and to the same dependence of the activation energy on the reorganization energy and the standard reaction free energy. Within the approximations of a continuum model of the solvent and linear response of the longitudinal polarization to the electric field in Marcus' theory, both formulations of the reaction coordinate are expected to lead to the same results.

  20. Entropic forces in Brownian motion

    OpenAIRE

    Roos, Nico

    2013-01-01

    The interest in the concept of entropic forces has risen considerably since E. Verlinde proposed to interpret the force in Newton s second law and Gravity as entropic forces [1]. Brownian motion, the motion of a small particle (pollen) driven by random impulses from the surrounding molecules, may be the first example of a stochastic process in which such forces are expected to emerge. In this note it is shown that at least two types of entropic force can be identified in the...