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

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

NARCIS (Netherlands)

Kluitenberg, Bas; Bredeweg, Steef W.; Zijlstra, Sjouke; Zijlstra, Wiebren; Buist, Ida

2012-01-01

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

Grounding the RPA Force: Why Machine Needs Man

Science.gov (United States)

2016-06-01

AU/ACSC/2016 AIR COMMAND AND STAFF COLLEGE AIR UNIVERSITY GROUNDING THE RPA FORCE: WHY MACHINE NEEDS MAN by Charles M. Washuk, Major, USAF (MBA...6 CHALLENGES OF MANNED FLIGHT...tactics will still require the presence of an operator, or “ man .” This paper focuses on the need for the Air Force to address the 18X career field and

Exact ground and excited states of an antiferromagnetic quantum spin model

International Nuclear Information System (INIS)

Bose, I.

1989-08-01

A quasi-one-dimensional spin model which consists of a chain of octahedra of spins has been suggested for which a certain parameter regime of the Hamiltonian, the ground state, can be written down exactly. The ground state is highly degenerate and can be other than a singlet. Also, several excited states can be constructed exactly. The ground state is a local RVB state for which resonance is confined to rings of spins. Some exact numerical results for an octahedron of spins have also been reported. (author). 16 refs, 2 figs, 1 tab

Graphene ground states

Science.gov (United States)

Friedrich, Manuel; Stefanelli, Ulisse

2018-06-01

Graphene is locally two-dimensional but not flat. Nanoscale ripples appear in suspended samples and rolling up often occurs when boundaries are not fixed. We address this variety of graphene geometries by classifying all ground-state deformations of the hexagonal lattice with respect to configurational energies including two- and three-body terms. As a consequence, we prove that all ground-state deformations are either periodic in one direction, as in the case of ripples, or rolled up, as in the case of nanotubes.

Ground states of a spin-boson model

International Nuclear Information System (INIS)

Amann, A.

1991-01-01

Phase transition with respect to ground states of a spin-boson Hamiltonian are investigated. The spin-boson model under discussion consists of one spin and infinitely many bosons with a dipole-type coupling. It is shown that the order parameter of the model vanishes with respect to arbitrary ground states if it vanishes with respect to ground states obtained as (biased) temperature to zero limits of thermic equilibrium states. The ground states of the latter special type have been investigated by H. Spohn. Spohn's respective phase diagrams are therefore valid for arbitrary ground states. Furthermore, disjointness of ground states in the broken symmetry regime is examined

NRC Task Force report on review of the Federal/State program for regulation of commercial low-level radioactive waste burial grounds. Analysis of public comments

International Nuclear Information System (INIS)

1977-09-01

Correspondence after publication of NUREG-0217 in the Federal Register is listed by docket. A summary of the comments is given. Comments on the task force conclusions on federal/state roles, comprehensive regulator program, and need to study alternatives, provide adequate capacity, and avoid proliferation are analyzed. A breakdown of the comments of states, industry, and others on the task force conclusions and recommendations is tabulated

Differences in pediatric vertical ground reaction force between planovalgus and neutrally aligned feet.

Science.gov (United States)

Pauk, Jolanta; Szymul, Joanna

2014-01-01

Ground reaction forces (GRF) reflect the force history of human body contact with the ground. The purpose of this study was to explore human gait abnormalities due to planovalgus by comparing vertical GRF data between individuals with planovalgus and those with neutrally aligned feet. Second we estimated associations between various measurements and vertical GRF parameters in a pediatric population. Boys and girls between the ages of 4 and 18 years (72 planovalgus feet and 74 neutrally aligned feet) took part in this study. Ground reaction forces were recorded by two Kistler platforms and normalized to body weight. Comparison of vertical GRF between planovalgus and neutrally aligned feet suggests that the first and the second peaks of vertical force (Fz1, Fz2) are most affected by planovalgus. The results also indicate that neutrally aligned feet display a different ground reaction force pattern than planovalgus, and that differences between boys and girls may be observed. The shape of the vertical GRF curve can help in clinical interpretation of abnormal gait.

Magnetic excitons in singlet-ground-state ferromagnets

DEFF Research Database (Denmark)

Birgeneau, R.J.; Als-Nielsen, Jens Aage; Bucher, E.

1971-01-01

The authors report measurements of the dispersion of singlet-triplet magnetic excitons as a function of temperature in the singlet-ground-state ferromagnets fcc Pr and Pr3Tl. Well-defined excitons are observed in both the ferromagnetic and paramagnetic regions, but with energies which are nearly...

Energies of the ground state and first excited 0 sup + state in an exactly solvable pairing model

CERN Document Server

Dinh Dang, N

2003-01-01

Several approximations are tested by calculating the ground-state energy and the energy of the first excited 0 sup + state using an exactly solvable model with two symmetric levels interacting via a pairing force. They are the BCS approximation (BCS), Lipkin-Nogami (LN) method, random-phase approximation (RPA), quasiparticle RPA (QRPA), the renormalized RPA (RRPA), and renormalized QRPA (RQRPA). It is shown that, in the strong-coupling regime, the QRPA which neglects the scattering term of the model Hamiltonian offers the best fit to the exact solutions. A recipe is proposed using the RRPA and RQRPA in combination with the pairing gap given by the LN method. Applying this recipe, it is shown that the superfluid-normal phase transition is avoided, and a reasonably good description for both of the ground-state energy and the energy of the first excited 0 sup + state is achieved. (orig.)

Search for the weak non-analog Fermi branch in the 42Sc ground state beta decay

International Nuclear Information System (INIS)

DelVecchio, R.M.; Daehnick, W.W.

1978-01-01

We have searched for the β-decay branch from the 4 2Sc ground state to the 1.837 MeV level in 4 2Ca. Since both states are J/sup π/ = 0 + , T = 1, this decay is an example of a non-analog Fermi decay which could occur by reason of some mixing of the analog ground states into the lowest excited 0 + state in both 4 2Sc and 4 2Ca. As a signal for this branch, we looked for a subsequent cascade γ ray with a Ge(Li) detector-rabbit arrangement. We found a branching ratio of (2.2 +- 1.7) x 10 - 5 relative to the superallowed ground state to ground state decay. Interpreted as an upper limit, this corresponds to a branching ratio - 5 at the 68% confidence level. This result is at the lower bound of what present theory can predict with a Coulomb force mixing calculation

The response of grounded ice to ocean temperature forcing in a coupled ice sheet-ice shelf-ocean cavity model

Science.gov (United States)

Goldberg, D. N.; Little, C. M.; Sergienko, O. V.; Gnanadesikan, A.

2010-12-01

Ice shelves provide a pathway for the heat content of the ocean to influence continental ice sheets. Changes in the rate or location of basal melting can alter their geometry and effect changes in stress conditions at the grounding line, leading to a grounded ice response. Recent observations of ice streams and ice shelves in the Amundsen Sea sector of West Antarctica have been consistent with this story. On the other hand, ice dynamics in the grounding zone control flux into the shelf and thus ice shelf geometry, which has a strong influence on the circulation in the cavity beneath the shelf. Thus the coupling between the two systems, ocean and ice sheet-ice shelf, can be quite strong. We examine the response of the ice sheet-ice shelf-ocean cavity system to changes in ocean temperature using a recently developed coupled model. The coupled model consists a 3-D ocean model (GFDL's Generalized Ocean Layered Dynamics model, or GOLD) to a two-dimensional ice sheet-ice shelf model (Goldberg et al, 2009), and allows for changing cavity geometry and a migrating grounding line. Steady states of the coupled system are found even under considerable forcing. The ice shelf morphology and basal melt rate patterns of the steady states exhibit detailed structure, and furthermore seem to be unique and robust. The relationship between temperature forcing and area-averaged melt rate is influenced by the response of ice shelf morphology to thermal forcing, and is found to be sublinear in the range of forcing considered. However, results suggest that area-averaged melt rate is not the best predictor of overall system response, as grounding line stability depends on local aspects of the basal melt field. Goldberg, D N, D M Holland and C G Schoof, 2009. Grounding line movement and ice shelf buttressing in marine ice sheets, Journal of Geophysical Research-Earth Surfaces, 114, F04026.

Three-Axis Ground Reaction Force Distribution during Straight Walking.

Science.gov (United States)

Hori, Masataka; Nakai, Akihito; Shimoyama, Isao

2017-10-24

We measured the three-axis ground reaction force (GRF) distribution during straight walking. Small three-axis force sensors composed of rubber and sensor chips were fabricated and calibrated. After sensor calibration, 16 force sensors were attached to the left shoe. The three-axis force distribution during straight walking was measured, and the local features of the three-axis force under the sole of the shoe were analyzed. The heel area played a role in receiving the braking force, the base area of the fourth and fifth toes applied little vertical or shear force, the base area of the second and third toes generated a portion of the propulsive force and received a large vertical force, and the base area of the big toe helped move the body's center of mass to the other foot. The results demonstrate that measuring the three-axis GRF distribution is useful for a detailed analysis of bipedal locomotion.

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

Science.gov (United States)

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

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 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. Key pointsGround reaction forces and joint moments during lateral stepping are smaller in magnitude than those experienced during moderate running.Force exposure in SS and XS gaits in normal play does not appear to contribute to the development of

Loading Configurations and Ground Reaction Forces During Treadmill Running in Weightlessness

Science.gov (United States)

DeWitt, John; Schaffner, Grant; Blazine, Kristi; Bentley, Jason; Laughlin, Mitzi; Loehr, James; Hagan, Donald

2003-01-01

Studies have shown losses in bone mineral density of 1-2% per month in critical weight bearing areas such as the proximal femur during long-term space flight (Grigoriev, 1998). The astronauts currently onboard the International Space Station (ISS) use a treadmill as an exercise countermeasure to bone loss that occurs as a result of prolonged exposure to weightlessness. A crewmember exercising on the treadmill is attached by a harness and loading device. Ground reaction forces are obtained through the loading device that pulls the crewn1ember towards the treadmill surface during locomotion. McCrory et al. (2002) found that the magnitude of the peak ground reaction force (pGRF) during horizontal suspension running, or simulated weightlessness, was directly related to the load applied to the subject. It is thought that strain magnitude and strain rate affects osteogenesis, and is a function of the magnitude and rate of change of the ground reaction force. While it is not known if a minimum stimulus exists for osteogenesis, it has been hypothesized that in order to replicate the bone formation occurring in normal gravity (1 G), the exercise in weightlessness should mimic the forces that occur on earth. Specifically, the pGRF obtained in weightlessness should be comparable to that achieved in 1 G.

[Environmental investigation of ground water contamination at Wright-Patterson Air Force Base, Ohio]. Volume 5, Field Investigation report

Energy Technology Data Exchange (ETDEWEB)

1992-03-01

An environmental investigation of ground water conditions has been undertaken at Wright-Patterson Air Force Base (WPAFB), Ohio to obtain data to assist in the evaluation of a potential removal action to prevent, to the extent practicable, migration of the contaminated ground water across Base boundaries. Field investigations were limited to the central section of the southwestern boundary of Area C and the Springfield Pike boundary of Area B. Further, the study was limited to a maximum depth of 150 feet below grade. Three primary activities of the field investigation were: (1) installation of 22 monitoring wells, (2) collection and analysis of ground water from 71 locations, (3) measurement of ground water elevations at 69 locations. Volatile organic compounds including trichloroethylene, perchloroethylene, and/or vinyl chloride were detected in concentrations exceeding Maximum Contaminant Levels (MCL) at three locations within the Area C investigation area. Ground water at the Springfield Pike boundary of Area B occurs in two primary units, separated by a thicker-than-expected clay layers. One well within Area B was determined to exceed the MCL for trichloroethylene.

United States Air Force Agency Financial Report 2013

Science.gov (United States)

2013-01-01

the DoD and number two in the federal government for its purchase and on site production of green power. The Air Force more than doubled its number...protect the contract work from state or local taxation , liens or attachment by the contractor’s creditors, transfer of property, or disposition in...the Air Force’s jurisdiction . The fund is available to such institutions or organizations subject to the terms of the gift, device, or bequest

Ground reaction force comparison of controlled resistance methods to isoinertial loading of the squat exercise - biomed 2010.

Science.gov (United States)

Paulus, David C; Reynolds, Michael C; Schilling, Brian K

2010-01-01

The ground reaction force during the concentric (raising) portion of the squat exercise was compared to that of isoinertial loading (free weights) for three pneumatically controlled resistance methods: constant resistance, cam force profile, and proportional force control based on velocity. Constant force control showed lower ground reaction forces than isoinertial loading throughout the range of motion (ROM). The cam force profile exhibited slightly greater ground reaction forces than isoinertial loading at 10 and 40% ROM with fifty-percent greater loading at 70% ROM. The proportional force control consistently elicited greater ground reaction force than isoinertial loading, which progressively ranged from twenty to forty percent increase over isoinertial loading except for being approximately equal at 85% ROM. Based on these preliminary results, the proportional control shows the most promise for providing loading that is comparable in magnitude to isoinertial loading. This technology could optimize resistance exercise for sport-specific training or as a countermeasure to atrophy during spaceflight.

Ground states of quantum spin systems

International Nuclear Information System (INIS)

Bratteli, Ola; Kishimoto, Akitaka; Robinson, D.W.

1978-07-01

The authors prove that ground states of quantum spin systems are characterized by a principle of minimum local energy and that translationally invariant ground states are characterized by the principle of minimum energy per unit volume

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

AAPM/SNMMI Joint Task Force: report on the current state of nuclear medicine physics training

Science.gov (United States)

Allison, Jerry D.; Clements, Jessica B.; Coffey, Charles W.; Fahey, Frederic H.; Gress, Dustin A.; Kinahan, Paul E.; Nickoloff, Edward L.; Mawlawi, Osama R.; MacDougall, Robert D.; Pizzuitello, Robert J.

2015-01-01

The American Association of Physicists in Medicine (AAPM) and the Society of Nuclear Medicine and Molecular Imaging (SNMMI) recognized the need for a review of the current state of nuclear medicine physics training and the need to explore pathways for improving nuclear medicine physics training opportunities. For these reasons, the two organizations formed a joint AAPM/SNMMI Ad Hoc Task Force on Nuclear Medicine Physics Training. The mission of this task force was to assemble a representative group of stakeholders to: Estimate the demand for board‐certified nuclear medicine physicists in the next 5–10 years,Identify the critical issues related to supplying an adequate number of physicists who have received the appropriate level of training in nuclear medicine physics, andIdentify approaches that may be considered to facilitate the training of nuclear medicine physicists. As a result, a task force was appointed and chaired by an active member of both organizations that included representation from the AAPM, SNMMI, the American Board of Radiology (ABR), the American Board of Science in Nuclear Medicine (ABSNM), and the Commission for the Accreditation of Medical Physics Educational Programs (CAMPEP). The Task Force first met at the AAPM Annual Meeting in Charlotte in July 2012 and has met regularly face‐to‐face, online, and by conference calls. This manuscript reports the findings of the Task Force, as well as recommendations to achieve the stated mission. PACS number: 01.40.G‐ PMID:26699325

The influence of cricket fast bowlers' front leg technique on peak ground reaction forces.

Science.gov (United States)

Worthington, Peter; King, Mark; Ranson, Craig

2013-01-01

High ground reaction forces during the front foot contact phase of the bowling action are believed to be a major contributor to the high prevalence of lumbar stress fractures in fast bowlers. This study aimed to investigate the influence of front leg technique on peak ground reaction forces during the delivery stride. Three-dimensional kinematic data and ground reaction forces during the front foot contact phase were captured for 20 elite male fast bowlers. Eight kinematic parameters were determined for each performance, describing run-up speed and front leg technique, in addition to peak force and time to peak force in the vertical and horizontal directions. There were substantial variations between bowlers in both peak forces (vertical 6.7 ± 1.4 body weights; horizontal (braking) 4.5 ± 0.8 body weights) and times to peak force (vertical 0.03 ± 0.01 s; horizontal 0.03 ± 0.01 s). These differences were found to be linked to the orientation of the front leg at the instant of front foot contact. In particular, a larger plant angle and a heel strike technique were associated with lower peak forces and longer times to peak force during the front foot contact phase, which may help reduce the likelihood of lower back injuries.

Government Applications Task Force ground truth study of WAG 4

International Nuclear Information System (INIS)

Evers, T.K.; Smyre, J.L.; King, A.L.

1997-06-01

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

New York state high-speed surface transportation study: Final report

Energy Technology Data Exchange (ETDEWEB)

1994-08-01

In 1990, New York State Governor Mario M. Cuomo created an interagency task force under the leadership of Lt. Governor Stan Lundine to investigate the potential of high speed ground transportation (HSGT) systems. Building on information from previous agency activities, including consultant efforts contracted by the New York State Energy Research and Development Authority (NYSERDA), the New York State Thruway Authority (NYSTA), and in-house analyses performed by New York State Department of Transportation (NYSDOT), the task force focused on the corridor between New York City and the Niagara Frontier. In December 1991, NYSERDA issued a contract for a study of high speed ground transportation options for New York State. The study`s objective was to assess potential rights-of-way, ridership, energy and environmental impacts, economic benefits, capital, operating, and maintenance costs, and financial viability of HSGT systems. This study builds upon and supplements previous and on-going HSGT activities conducted by the members of the interagency task force. These activities include: Maglev Technical and Economic Feasibility Study (NYSERDA); Maglev Demonstration Site Investigation (NYSTA); and New York/Massachusetts High Speed Ground Transportation Study (NYSDOT). This study is intended to verify and refine previous information and analyses and provide supplemental information and insights to be used in determining if additional investigation and activities involving HSGT are desirable for New York State. This study evaluates HSGT technologies capable of speeds significantly higher than those achieved with the present rail system. Three HSGT categories are used in this study: incremental rail improvement, very high-speed rail, and Maglev.

Entanglement of two ground state neutral atoms using Rydberg blockade

DEFF Research Database (Denmark)

Miroshnychenko, Yevhen; Browaeys, Antoine; Evellin, Charles

2011-01-01

We report on our recent progress in trapping and manipulation of internal states of single neutral rubidium atoms in optical tweezers. We demonstrate the creation of an entangled state between two ground state atoms trapped in separate tweezers using the effect of Rydberg blockade. The quality...... of the entanglement is measured using global rotations of the internal states of both atoms....

Solid-state nuclear-spin quantum computer based on magnetic resonance force microscopy

International Nuclear Information System (INIS)

Berman, G. P.; Doolen, G. D.; Hammel, P. C.; Tsifrinovich, V. I.

2000-01-01

We propose a nuclear-spin quantum computer based on magnetic resonance force microscopy (MRFM). It is shown that an MRFM single-electron spin measurement provides three essential requirements for quantum computation in solids: (a) preparation of the ground state, (b) one- and two-qubit quantum logic gates, and (c) a measurement of the final state. The proposed quantum computer can operate at temperatures up to 1 K. (c) 2000 The American Physical Society

Quinoidal Oligo(9,10-anthryl)s with Chain-Length-Dependent Ground States: A Balance between Aromatic Stabilization and Steric Strain Release

KAUST Repository

Lim, Zhenglong

2015-11-12

Quinoidal π-conjugated polycyclic hydrocarbons have attracted intensive research interest due to their unique optical/electronic properties and possible magnetic activity, which arises from a thermally excited triplet state. However, there is still lack of fundamental understanding on the factors that determine the electronic ground states. Herein, by using quinoidal oligo(9,10-anthryl)s, it is demonstrated that both aromatic stabilisation and steric strain release play balanced roles in determining the ground states. Oligomers with up to four anthryl units were synthesised and their ground states were investigated by electronic absorption and electron spin resonance (ESR) spectroscopy, assisted by density functional theory (DFT) calculations. The quinoidal 9,10-anthryl dimer 1 has a closed-shell ground state, whereas the tri- (2) and tetramers (3) both have an open-shell diradical ground state with a small singlet-triplet gap. Such a difference results from competition between two driving forces: the large steric repulsion between the anthryl/phenyl units in the closed-shell quinoidal form that drives the molecule to a flexible open-shell diradical structure, and aromatic stabilisation due to the gain of more aromatic sextet rings in the closed-shell form, which drives the molecule towards a contorted quinoidal structure. The ground states of these oligomers thus depend on the overall balance between these two driving forces and show chain-length dependence. © 2015 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Gamow-Teller strength function for 90Zr: Effects of spin and isospin exchange forces, and ground-state correlations

International Nuclear Information System (INIS)

Mathews, G.J.; Bloom, S.D.; Hausman, R.F. Jr.

1983-01-01

Shell-model calculations of the Gamow-Teller strength function for 90 Zr have been performed utilizing a realistic finite-range two-body interaction in a model space consisting of the 2p and 1g shells. The effects of admixtures of two-particle two-hole excitations in 90 Nb, mostly due to the spin and isospin exchange components of the nucleon-nucleon force, are discussed. Ground state correlations in 90 Zr are also added via seniority-zero two-proton excitations from the 2p shell into the 1g/sub 9/2/ shell. With the correlations the Gamow-Teller strength function is in good agreement with the experimental results and accounts for essentially all of the observed dispersion of strength. The inclusion of these correlations does not, however, produce either a displacement of Gamow-Teller strength to higher excitation energies, or a significant change in the total strength. Thus, they cannot account for the observed Gamow-Teller quenching. The quenching factor derived by a comparison of our calculated results with experiment is 0.52

Sit-to-stand ground reaction force characteristics in blind and sighted female children.

Science.gov (United States)

Faraji Aylar, Mozhgan; Jafarnezhadgero, Amir Ali; Salari Esker, Fatemeh

2018-03-05

The association between visual sensory and sit-to-stand ground reaction force characteristics is not clear. Impulse is the amount of force applied over a period of time. Also, free moment represents the vertical moment applied in the center of pressure (COP). How the ground reaction force components, vertical loading rate, impulses and free moment respond to long and short term restricted visual information? Fifteen female children with congenital blindness and 45 healthy girls with no visual impairments participated in this study. The girls with congenital blindness were placed in one group and the 45 girls with no visual impairments were randomly divided into three groups of 15; eyes open, permanently eyes closed, and temporary eyes closed. The participants in the permanently eyes closed group closed their eyes for 20 min before the test, whereas temporary eyes closed group did tests with their eyes closed throughout, and those in the eyes open group kept their eyes open. Congenital blindness was associated with increased vertical loading rate, range of motion of knee and hip in the medio-lateral plane. Also, medio-lateral and vertical ground reaction force impulses. Similar peak negative and positive free moments were observed in three groups. In conclusion, the results reveal that sit-to-stand ground reaction force components in blind children may have clinical importance for improvement of balance control of these individuals. Copyright © 2018 Elsevier B.V. All rights reserved.

On the ground state of Yang-Mills theory

International Nuclear Information System (INIS)

Bakry, Ahmed S.; Leinweber, Derek B.; Williams, Anthony G.

2011-01-01

Highlights: → The ground state overlap for sets of meson potential trial states is measured. → Non-uniform gluonic distributions are probed via Wilson loop operator. → The locally UV-regulated flux-tube operators can optimize the ground state overlap. - Abstract: We investigate the overlap of the ground state meson potential with sets of mesonic-trial wave functions corresponding to different gluonic distributions. We probe the transverse structure of the flux tube through the creation of non-uniform smearing profiles for the string of glue connecting two color sources in Wilson loop operator. The non-uniformly UV-regulated flux-tube operators are found to optimize the overlap with the ground state and display interesting features in the ground state overlap.

Self-Tuning Threshold Method for Real-Time Gait Phase Detection Based on Ground Contact Forces Using FSRs

Directory of Open Access Journals (Sweden)

Jing Tang

2018-02-01

Full Text Available This paper presents a novel methodology for detecting the gait phase of human walking on level ground. The previous threshold method (TM sets a threshold to divide the ground contact forces (GCFs into on-ground and off-ground states. However, the previous methods for gait phase detection demonstrate no adaptability to different people and different walking speeds. Therefore, this paper presents a self-tuning triple threshold algorithm (STTTA that calculates adjustable thresholds to adapt to human walking. Two force sensitive resistors (FSRs were placed on the ball and heel to measure GCFs. Three thresholds (i.e., high-threshold, middle-threshold andlow-threshold were used to search out the maximum and minimum GCFs for the self-adjustments of thresholds. The high-threshold was the main threshold used to divide the GCFs into on-ground and off-ground statuses. Then, the gait phases were obtained through the gait phase detection algorithm (GPDA, which provides the rules that determine calculations for STTTA. Finally, the STTTA reliability is determined by comparing the results between STTTA and Mariani method referenced as the timing analysis module (TAM and Lopez–Meyer methods. Experimental results show that the proposed method can be used to detect gait phases in real time and obtain high reliability when compared with the previous methods in the literature. In addition, the proposed method exhibits strong adaptability to different wearers walking at different walking speeds.

Search for the QCD ground state

International Nuclear Information System (INIS)

Reuter, M.; Wetterich, C.

1994-05-01

Within the Euclidean effective action approach we propose criteria for the ground state of QCD. Despite a nonvanishing field strength the ground state should be invariant with respect to modified Poincare transformations consisting of a combination of translations and rotations with suitable gauge transformations. We have found candidate states for QCD with four or more colours. The formation of gluon condensates shows similarities with the Higgs phenomenon. (orig.)

Lower limb ice application alters ground reaction force during gait initiation

Directory of Open Access Journals (Sweden)

Thiago B. Muniz

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 young 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.

Is the ground state of Yang-Mills theory Coulombic?

Science.gov (United States)

Heinzl, T.; Ilderton, A.; Langfeld, K.; Lavelle, M.; Lutz, W.; McMullan, D.

2008-08-01

We study trial states modelling the heavy quark-antiquark ground state in SU(2) Yang-Mills theory. A state describing the flux tube between quarks as a thin string of glue is found to be a poor description of the continuum ground state; the infinitesimal thickness of the string leads to UV artifacts which suppress the overlap with the ground state. Contrastingly, a state which surrounds the quarks with non-Abelian Coulomb fields is found to have a good overlap with the ground state for all charge separations. In fact, the overlap increases as the lattice regulator is removed. This opens up the possibility that the Coulomb state is the true ground state in the continuum limit.

MEMS two-axis force plate array used to measure the ground reaction forces during the running motion of an ant

International Nuclear Information System (INIS)

Takahashi, Hidetoshi; Thanh-Vinh, Nguyen; Jung, Uijin G; Shimoyama, Isao; Matsumoto, Kiyoshi

2014-01-01

A terrestrial insect can perform agile running maneuvers. However, the balance of ground reaction forces (GRFs) between each leg in an insect have remained poorly characterized. In this report, we present a micro force plate array for the simultaneous measurement of the anterior and vertical components of GRFs of multiple legs during the running motion of an ant. The proposed force plate, which consists of a 2000 µm × 980 µm × 20 µm plate base as the contact surface of an ant's leg, and the supported beams with piezoresistors on the sidewall and surface are sufficiently compact to be adjacently arrayed along the anterior direction. Eight plates arrayed in parallel were fabricated on the same silicon-on-insulator substrate to narrow the gap between each plate to 20 µm. We compartmented the plate surface into 32 blocks and evaluated the sensitivities to two-axis forces in each block so that the exerted forces could be detected wherever a leg came into contact. The force resolutions in both directions were under 1 µN within ±20 µN. Using the fabricated force plate array, we achieved a simultaneous measurement of the GRFs of three legs on one side while an ant was running. (paper)

Is the ground state of Yang-Mills theory Coulombic?

OpenAIRE

Heinzl, Thomas; Ilderton, Anton; Langfeld, Kurt; Lavelle, Martin; Lutz, Wolfgang; McMullan, David

2008-01-01

We study trial states modelling the heavy quark-antiquark ground state in SU(2) Yang-Mills theory. A state describing the flux tube between quarks as a thin string of glue is found to be a poor description of the continuum ground state; the infinitesimal thickness of the string leads to UV artifacts which suppress the overlap with the ground state. Contrastingly, a state which surrounds the quarks with non-abelian Coulomb fields is found to have a good overlap with the ground state for all ch...

α-decay half-lives of some nuclei from ground state to ground state using different nuclear potential

Directory of Open Access Journals (Sweden)

Akrawy Dashty T.

2018-01-01

Full Text Available Theoretical α-decay half-lives of some nuclei from ground state to ground state are calculated using different nuclear potential model including Coulomb proximity potential (CPPM, Royer proximity potential and Broglia and Winther 1991. The calculated values comparing with experimental data, it is observed that the CPPM model is in good agreement with the experimental data.

Nuclear ground state

International Nuclear Information System (INIS)

Negele, J.W.

1975-01-01

The nuclear ground state is surveyed theoretically, and specific suggestions are given on how to critically test the theory experimentally. Detailed results on 208 Pb are discussed, isolating several features of the charge density distributions. Analyses of 208 Pb electron scattering and muonic data are also considered. 14 figures

Neutrino ground state in a dense star

International Nuclear Information System (INIS)

Kiers, K.; Tytgat, M.H.

1998-01-01

It has recently been argued that long range forces due to the exchange of massless neutrinos give rise to a very large self-energy in a dense, finite-ranged, weakly charged medium. Such an effect, if real, would destabilize a neutron star. To address this issue we have studied the related problem of a massless neutrino field in the presence of an external, static electroweak potential of finite range. To be precise, we have computed to one loop the exact vacuum energy for the case of a spherical square well potential of depth α and radius R. For small wells, the vacuum energy is reliably determined by a perturbative expansion in the external potential. For large wells, however, the perturbative expansion breaks down. A manifestation of this breakdown is that the vacuum carries a non-zero neutrino charge. The energy and neutrino charge of the ground state are, to a good approximation for large wells, those of a neutrino condensate with chemical potential μ=α. Our results demonstrate explicitly that long-range forces due to the exchange of massless neutrinos do not threaten the stability of neutron stars. copyright 1998 The American Physical Society

Rayleigh approximation to ground state of the Bose and Coulomb glasses

Science.gov (United States)

Ryan, S. D.; Mityushev, V.; Vinokur, V. M.; Berlyand, L.

2015-01-01

Glasses are rigid systems in which competing interactions prevent simultaneous minimization of local energies. This leads to frustration and highly degenerate ground states the nature and properties of which are still far from being thoroughly understood. We report an analytical approach based on the method of functional equations that allows us to construct the Rayleigh approximation to the ground state of a two-dimensional (2D) random Coulomb system with logarithmic interactions. We realize a model for 2D Coulomb glass as a cylindrical type II superconductor containing randomly located columnar defects (CD) which trap superconducting vortices induced by applied magnetic field. Our findings break ground for analytical studies of glassy systems, marking an important step towards understanding their properties. PMID:25592417

Derivation of the RPA (Random Phase Approximation) Equation of ATDDFT (Adiabatic Time Dependent Density Functional Ground State Response Theory) from an Excited State Variational Approach Based on the Ground State Functional.

Science.gov (United States)

Ziegler, Tom; Krykunov, Mykhaylo; Autschbach, Jochen

2014-09-09

The random phase approximation (RPA) equation of adiabatic time dependent density functional ground state response theory (ATDDFT) has been used extensively in studies of excited states. It extracts information about excited states from frequency dependent ground state response properties and avoids, thus, in an elegant way, direct Kohn-Sham calculations on excited states in accordance with the status of DFT as a ground state theory. Thus, excitation energies can be found as resonance poles of frequency dependent ground state polarizability from the eigenvalues of the RPA equation. ATDDFT is approximate in that it makes use of a frequency independent energy kernel derived from the ground state functional. It is shown in this study that one can derive the RPA equation of ATDDFT from a purely variational approach in which stationary states above the ground state are located using our constricted variational DFT (CV-DFT) method and the ground state functional. Thus, locating stationary states above the ground state due to one-electron excitations with a ground state functional is completely equivalent to solving the RPA equation of TDDFT employing the same functional. The present study is an extension of a previous work in which we demonstrated the equivalence between ATDDFT and CV-DFT within the Tamm-Dancoff approximation.

Forelimb and hindlimb ground reaction forces of walking cats: assessment and comparison with walking dogs.

Science.gov (United States)

Corbee, R J; Maas, H; Doornenbal, A; Hazewinkel, H A W

2014-10-01

The primary aim of this study was to assess the potential of force plate analysis for describing the stride cycle of the cat. The secondary aim was to define differences in feline and canine locomotion based on force plate characteristics. Ground reaction forces of 24 healthy cats were measured and compared with ground reaction forces of 24 healthy dogs. Force-time waveforms in cats generated by force plate analysis were consistent, as reflected by intra-class correlation coefficients for peak vertical force, peak propulsive force and peak braking force (0.94-0.95, 0.85-0.89 and 0.89-0.90, respectively). Compared with dogs, cats had a higher peak vertical force during the propulsion phase (cat, 3.89 ± 0.19 N/kg; dog, 3.03 ± 0.16 N/kg), and a higher hindlimb propulsive force (cat, -1.08 ± 0.13 N/kg; dog, (-0.87 ± 0.13 N/kg) and hindlimb impulse (cat, -0.18 ± 0.03 N/kg; dog, -0.14 ± 0.02 N/kg). Force plate analysis is a valuable tool for the assessment of locomotion in cats, because it can be applied in the clinical setting and provides a non-invasive and objective measurement of locomotion characteristics with high repeatability in cats, as well as information about kinetic characteristics. Differences in force-time waveforms between cats and dogs can be explained by the more crouched position of cats during stance and their more compliant gait compared with dogs. Feline waveforms of the medio-lateral ground reaction forces also differ between cats and dogs and this can be explained by differences in paw supination-pronation. Copyright © 2014 Elsevier Ltd. All rights reserved.

Hydrogeology and simulation of ground-water flow at Arnold Air Force Base, Coffee and Franklin counties, Tennessee

Science.gov (United States)

Haugh, C.J.; Mahoney, E.N.

1994-01-01

The U.S. Air Force at Arnold Air Force Base (AAFB), in Coffee and Franklin Counties, Tennessee, is investigating ground-water contamination in selected areas of the base. This report documents the results of a comprehensive investigation of the regional hydrogeology of the AAFB area. Three aquifers within the Highland Rim aquifer system, the shallow aquifer, the Manchester aquifer, and the Fort Payne aquifer, have been identified in the study area. Of these, the Manchester aquifer is the primary source of water for domestic use. Drilling and water- quality data indicate that the Chattanooga Shale is an effective confining unit, isolating the Highland Rim aquifer system from the deeper, upper Central Basin aquifer system. A regional ground-water divide, approximately coinciding with the Duck River-Elk River drainage divide, underlies AAFB and runs from southwest to northeast. The general direction of most ground-water flow is to the north- west or to the northwest or to the southeast from the divide towards tributary streams that drain the area. Recharge estimates range from 4 to 11 inches per year. Digital computer modeling was used to simulate and provide a better understanding of the ground-water flow system. The model indicates that most of the ground-water flow occurs in the shallow and Manchester aquifers. The model was most sensitive to increases in hydraulic conductivity and changes in recharge rates. Particle-tracking analysis from selected sites of ground-water contamination indicates a potential for contami- nants to be transported beyond the boundary of AAFB.

Grizzly bear (Ursus arctos horribilis) locomotion: gaits and ground reaction forces.

Science.gov (United States)

Shine, Catherine L; Penberthy, Skylar; Robbins, Charles T; Nelson, O Lynne; McGowan, Craig P

2015-10-01

Locomotion of plantigrade generalists has been relatively little studied compared with more specialised postures even though plantigrady is ancestral among quadrupeds. Bears (Ursidae) are a representative family for plantigrade carnivorans, they have the majority of the morphological characteristics identified for plantigrade species, and they have the full range of generalist behaviours. This study compared the locomotion of adult grizzly bears (Ursus arctos horribilis Linnaeus 1758), including stride parameters, gaits and analysis of three-dimensional ground reaction forces, with that of previously studied quadrupeds. At slow to moderate speeds, grizzly bears use walks, running walks and canters. Vertical ground reaction forces demonstrated the typical M-shaped curve for walks; however, this was significantly more pronounced in the hindlimb. The rate of force development was also significantly higher for the hindlimbs than for the forelimbs at all speeds. Mediolateral forces were significantly higher than would be expected for a large erect mammal, almost to the extent of a sprawling crocodilian. There may be morphological or energetic explanations for the use of the running walk rather than the trot. The high medial forces (produced from a lateral push by the animal) could be caused by frontal plane movement of the carpus and elbow by bears. Overall, while grizzly bears share some similarities with large cursorial species, their locomotor kinetics have unique characteristics. Additional studies are needed to determine whether these characters are a feature of all bears or plantigrade species. © 2015. Published by The Company of Biologists Ltd.

Ambulatory measurement of ground reaction force and estimation of ankle and foot dynamics

NARCIS (Netherlands)

Schepers, H. Martin; Koopman, Hubertus F.J.M.; Baten, Christian T.M.; Veltink, Petrus H.

INTRODUCTION Traditionally, human body movement analysis is done in so-called ‘gait laboratories’. In these laboratories, body movement is measured by a camera system using optical markers, the ground reaction force by a force plate fixed in the floor, and the muscle activity by EMG. From the body

Classical many-particle systems with unique disordered ground states

Science.gov (United States)

Zhang, G.; Stillinger, F. H.; Torquato, S.

2017-10-01

Classical ground states (global energy-minimizing configurations) of many-particle systems are typically unique crystalline structures, implying zero enumeration entropy of distinct patterns (aside from trivial symmetry operations). By contrast, the few previously known disordered classical ground states of many-particle systems are all high-entropy (highly degenerate) states. Here we show computationally that our recently proposed "perfect-glass" many-particle model [Sci. Rep. 6, 36963 (2016), 10.1038/srep36963] possesses disordered classical ground states with a zero entropy: a highly counterintuitive situation . For all of the system sizes, parameters, and space dimensions that we have numerically investigated, the disordered ground states are unique such that they can always be superposed onto each other or their mirror image. At low energies, the density of states obtained from simulations matches those calculated from the harmonic approximation near a single ground state, further confirming ground-state uniqueness. Our discovery provides singular examples in which entropy and disorder are at odds with one another. The zero-entropy ground states provide a unique perspective on the celebrated Kauzmann-entropy crisis in which the extrapolated entropy of a supercooled liquid drops below that of the crystal. We expect that our disordered unique patterns to be of value in fields beyond glass physics, including applications in cryptography as pseudorandom functions with tunable computational complexity.

Bilateral contact ground reaction forces and contact times during plyometric drop jumping.

Science.gov (United States)

Ball, Nick B; Stock, Christopher G; Scurr, Joanna C

2010-10-01

Drop jumping (DJ) is used in training programs aimed to improve lower extremity explosive power. When performing double-leg drop jumps, it is important to provide an equal stimulus to both legs to ensure balanced development of the lower legs. The aim of this study was to bilaterally analyze the ground reactions forces and temporal components of drop jumping from 3 heights. Ten recreationally active male subjects completed 3 bounce-drop jumps from 3 starting heights (0.2, 0.4, and 0.6 m). Two linked force platforms were used to record left- and right-leg peak vertical force, time to peak force, average force, ground contact time, impulse and time differential. Between-height and between-leg comparisons for each variable were made using a multivariate analysis of variance with post hoc Wilcoxon tests (p < 0.05). Results indicated that force and time variables increased as drop jump height increased (p < 0.0001). Post hoc analyses showed that at 0.2- and 0.4-m bilateral differences were present in the time to peak force, average force, and impulse. No bilateral differences for any variables were shown at 0.6-m starting height. The contact time for all jumps was <0.26 seconds. At 0.2 m, only 63% of the subjects had a starting time differential of <0.01 seconds, rising to 96.3% at 0.6 m. The results indicated that 0.6 m is the suggested drop jump height to ensure that no bilateral differences in vertical forces and temporal components occur; however, shorter contact times were found at the lower heights.

Effects of Different Lifting Cadences on Ground Reaction Forces during the Squat Exercise

Science.gov (United States)

Bentley, Jason R.; Amonette, William E.; Hagan, R. Donald

2008-01-01

The purpose of this investigation was to determine the effect of different cadences on the ground reaction force (GRF(sub R)) during the squat exercise. It is known that squats performed with greater acceleration will produce greater inertial forces; however, it is not well understood how different squat cadences affect GRF(sub R). It was hypothesized that faster squat cadences will result in greater peak GRF(sub R). METHODS: Six male subjects (30.8+/-4.4 y, 179.5+/-8.9 cm, 88.8+/-13.3 kg) with previous squat experience performed three sets of three squats using three different cadences (FC = 1 sec descent/1 sec ascent; MC = 3 sec descent/1 sec ascent; SC = 4 sec descent/2 sec ascent) with barbell mass equal to body mass. Ground reaction force was used to calculate inertial force trajectories of the body plus barbell (FI(sub system)). Forces were normalized to body mass. RESULTS: Peak GRF(sub R) and peak FI(sub system) were significantly higher in FC squats compared to MC (p=0.0002) and SC (p=0.0002). Range of GRF(sub R) and FI(sub system) were also significantly higher in FC compared to MC (psquat cadences result in significantly greater peak GRF(sub R) due to the inertia of the system. GRF(sub R) was more dependent upon decent cadence than on ascent cadence. PRACTICAL APPLICATION: This study demonstrates that faster squat cadences produce greater ground reaction forces. Therefore, the use of faster squat cadences might enhance strength and power adaptations to long-term resistance exercise training. Key Words: velocity, weight training, resistive exercise

On the ground state of Yang-Mills theory

OpenAIRE

Bakry, Ahmed S.; Leinweber, Derek B.; Williams, Anthony G.

2011-01-01

We investigate the overlap of the ground state meson potential with sets of mesonic-trial wave functions corresponding to different gluonic distributions. We probe the transverse structure of the flux tube through the creation of non-uniform smearing profiles for the string of glue connecting two color sources in Wilson loop operator. The non-uniformly UV-regulated flux-tube operators are found to optimize the overlap with the ground state and display interesting features in the ground state ...

On the ground state of Yang-Mills theory

Science.gov (United States)

Bakry, Ahmed S.; Leinweber, Derek B.; Williams, Anthony G.

2011-08-01

We investigate the overlap of the ground state meson potential with sets of mesonic-trial wave functions corresponding to different gluonic distributions. We probe the transverse structure of the flux tube through the creation of non-uniform smearing profiles for the string of glue connecting two color sources in Wilson loop operator. The non-uniformly UV-regulated flux-tube operators are found to optimize the overlap with the ground state and display interesting features in the ground state overlap.

Reactive ground-state pathways are not ubiquitous in red/green cyanobacteriochromes.

Science.gov (United States)

Chang, Che-Wei; Gottlieb, Sean M; Kim, Peter W; Rockwell, Nathan C; Lagarias, J Clark; Larsen, Delmar S

2013-09-26

Recent characterization of the red/green cyanobacteriochrome (CBCR) NpR6012g4 revealed a high quantum yield for its forward photoreaction [J. Am. Chem. Soc. 2012, 134, 130-133] that was ascribed to the activity of hidden, productive ground-state intermediates. The dynamics of the pathways involving these ground-state intermediates was resolved with femtosecond dispersed pump-dump-probe spectroscopy, the first such study reported for any CBCR. To address the ubiquity of such second-chance initiation dynamics (SCID) in CBCRs, we examined the closely related red/green CBCR NpF2164g6 from Nostoc punctiforme. Both NpF2164g6 and NpR6012g4 use phycocyanobilin as the chromophore precursor and exhibit similar excited-state dynamics. However, NpF2164g6 exhibits a lower quantum yield of 32% for the generation of the isomerized Lumi-R primary photoproduct, compared to 40% for NpR6012g4. This difference arises from significantly different ground-state dynamics between the two proteins, with the SCID mechanism deactivated in NpF2164g6. We present an integrated inhomogeneous target model that self-consistently fits the pump-probe and pump-dump-probe signals for both forward and reverse photoreactions in both proteins. This work demonstrates that reactive ground-state intermediates are not ubiquitous phenomena in CBCRs.

Effects of Nordic walking and walking on spatiotemporal gait parameters and ground reaction force.

Science.gov (United States)

Park, Seung Kyu; Yang, Dae Jung; Kang, Yang Hun; Kim, Je Ho; Uhm, Yo Han; Lee, Yong Seon

2015-09-01

[Purpose] The purpose of this study was to investigate the effects of Nordic walking and walking on spatiotemporal gait parameters and ground reaction force. [Subjects] The subjects of this study were 30 young adult males, who were divided into a Nordic walking group of 15 subjects and a walking group of 15 subjects. [Methods] To analyze the spatiotemporal parameters and ground reaction force during walking in the two groups, the six-camera Vicon MX motion analysis system was used. The subjects were asked to walk 12 meters using the more comfortable walking method for them between Nordic walking and walking. After they walked 12 meters more than 10 times, their most natural walking patterns were chosen three times and analyzed. To determine the pole for Nordic walking, each subject's height was multiplied by 0.68. We then measured the spatiotemporal gait parameters and ground reaction force. [Results] Compared with the walking group, the Nordic walking group showed an increase in cadence, stride length, and step length, and a decrease in stride time, step time, and vertical ground reaction force. [Conclusion] The results of this study indicate that Nordic walking increases the stride and can be considered as helping patients with diseases affecting their gait. This demonstrates that Nordic walking is more effective in improving functional capabilities by promoting effective energy use and reducing the lower limb load, because the weight of the upper and lower limbs is dispersed during Nordic walking.

Hazardous materials on golf courses: Experience and knowledge of golf course superintendents and grounds maintenance workers from seven states

Science.gov (United States)

Arcury-Quandt, Alice E.; Gentry, Amanda L.; Marín, Antonio J.

2011-01-01

Background The golf course industry has a growing Latino work force. Little occupational health research has addressed this work force. This paper examines golf course superintendents’ and Latino grounds maintenance workers’ pesticide knowledge, beliefs, and safety training. In particular, it focuses on knowledge of and adherence to OSHA Right-to-Know regulations. Methods In person, in-depth interviews were conducted with ten golf course superintendents in five states and with sixteen Latino grounds maintenance workers in four states. Results Few superintendents were in compliance with Right-to-Know regulations or did pesticide safety training with all of their workers. Few workers had any pesticide safety knowledge. Most safety training on golf courses was rudimentary and focused on machine safety, and was usually conducted in the off-season or on rainy days, not before workers were assigned tasks. Conclusions More Right-to-Know training is necessary for superintendents and grounds maintenance workers. Culturally and linguistically appropriate Spanish language materials need to be developed or made more widely available to train workers. Better enforcement of safety and training regulations is necessary. PMID:21360723

Ground-water contamination at Wurtsmith Air Force Base, Michigan

Science.gov (United States)

Stark, J.R.; Cummings, T.R.; Twenter, F.R.

1983-01-01

A sand and gravel aquifer of glacial origin underlies Wurtsmith Air Force Base in northeastern lower Michigan. The aquifer overlies a thick clay layer at an average depth of 65 feet. The water table is about 10 feet below land surface in the western part of the Base and about 25 feet below land surface in the eastern part. A ground-water divide cuts diagonally across the Base from northwest to southeast. South of the divide, ground water flows to the Au Sable River; north of the divide, it flows to Van Etten Creek and Van Etten Lake. Mathematical models were used to aid in calculating rates of groundwater flow. Rates range from about 0.8 feet per day in the eastern part of the Base to about 0.3 feet per day in the western part. Models also were used as an aid in making decisions regarding purging of contaminated water from the aquifer. In 1977, trichloroethylene was detected in the Air Force Base water-supply system. It had leaked from a buried storage tank near Building 43 in the southeastern part of the Base and moved northeastward under the influence of the natural ground-water gradient and the pumping of Base water-supply wells. In the most highly contaminated part of the plume, concentrations are greater than 1,000 micrograms per liter. Current purge pumping is removing some of the trichloroethylene, and seems to have arrested its eastward movement. Pumping of additional purge wells could increase the rate of removal. Trichloroethylene has also been detected in ground water in the vicinity of the Base alert apron, where a plume from an unknown source extends northeastward off Base. A smaller, less well-defined area of contamination also occurs just north of the larger plume. Trichloroethylene, identified near the waste-treatment plant, seepage lagoons, and the northern landfill area, is related to activities and operations in these areas. Dichloroethylene and trichloroethylene occur in significant quantities westward of Building 43, upgradient from the major

Effects of load on ground reaction force and lower limb kinematics during concentric squats.

Science.gov (United States)

Kellis, Eleftherios; Arambatzi, Fotini; Papadopoulos, Christos

2005-10-01

The purpose of this study was to examine the effects of external load on vertical ground reaction force, and linear and angular kinematics, during squats. Eight males aged 22.1 +/- 0.8 years performed maximal concentric squats using loads ranging from 7 to 70% of one-repetition maximum on a force plate while linear barbell velocity and the angular kinematics of the hip, knee and ankle were recorded. Maximum, average and angle-specific values were recorded. The ground reaction force ranged from 1.67 +/- 0.20 to 3.21 +/- 0.29 times body weight and increased significantly as external load increased (P squat exercises is not achieved at the same position of the lower body as external load is increased. In contrast, joint velocity coordination does not change as load is increased. The force-velocity relationship was linear and independent from the set of data used for its determination.

Ground state searches in fcc intermetallics

International Nuclear Information System (INIS)

Wolverton, C.; de Fontaine, D.; Ceder, G.; Dreysse, H.

1991-12-01

A cluster expansion is used to predict the fcc ground states, i.e., the stable phases at zero Kelvin as a function of composition, for alloy systems. The intermetallic structures are not assumed, but derived regorously by minimizing the configurational energy subject to linear constraints. This ground state search includes pair and multiplet interactions which spatially extend to fourth nearest neighbor. A large number of these concentration-independent interactions are computed by the method of direct configurational averaging using a linearized-muffin-tin orbital Hamiltonian cast into tight binding form (TB-LMTO). The interactions, derived without the use of any adjustable or experimentally obtained parameters, are compared to those calculated via the generalized perturbation method extention of the coherent potential approximation within the context of a KKR Hamiltonian (KKR-CPA-GPM). Agreement with the KKR-CPA-GPM results is quite excellent, as is the comparison of the ground state results with the fcc-based portions of the experimentally-determined phase diagrams under consideration

Some fundamental properties of the ground state of atoms and molecules

International Nuclear Information System (INIS)

Lieb, E.H.

1986-01-01

This paper studies the ground states of atoms and molecules in quantum mechanics and reports on some mathematically rigourous results pertaining to the matter. The non-relativistic Hamiltonian for a molecule in the static nucleus approximation is presented along with notations

A rolling constraint reproduces ground reaction forces and moments in dynamic simulations of walking, running, and crouch gait.

Science.gov (United States)

Hamner, Samuel R; Seth, Ajay; Steele, Katherine M; Delp, Scott L

2013-06-21

Recent advances in computational technology have dramatically increased the use of muscle-driven simulation to study accelerations produced by muscles during gait. Accelerations computed from muscle-driven simulations are sensitive to the model used to represent contact between the foot and ground. A foot-ground contact model must be able to calculate ground reaction forces and moments that are consistent with experimentally measured ground reaction forces and moments. We show here that a rolling constraint can model foot-ground contact and reproduce measured ground reaction forces and moments in an induced acceleration analysis of muscle-driven simulations of walking, running, and crouch gait. We also illustrate that a point constraint and a weld constraint used to model foot-ground contact in previous studies produce inaccurate reaction moments and lead to contradictory interpretations of muscle function. To enable others to use and test these different constraint types (i.e., rolling, point, and weld constraints) we have included them as part of an induced acceleration analysis in OpenSim, a freely-available biomechanics simulation package. Copyright © 2013 Elsevier Ltd. All rights reserved.

Forelimb and hindlimb ground reaction forces of walking cats: Assessment and comparison with walking dogs

NARCIS (Netherlands)

Corbee, R.J.; Maas, H.; Doornenbal, A; Hazewinkel, H.A.W.

2014-01-01

The primary aim of this study was to assess the potential of force plate analysis for describing the stride cycle of the cat. The secondary aim was to define differences in feline and canine locomotion based on force plate characteristics. Ground reaction forces of 24 healthy cats were measured and

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

International Nuclear Information System (INIS)

Truong, Tien Van; Yoon, Kwang Joon; Byun, Doyoung; Kim, Min Jun; Park, Hoon Cheol

2013-01-01

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 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

Singlet Ground State Magnetism:

DEFF Research Database (Denmark)

Loidl, A.; Knorr, K.; Kjems, Jørgen

1979-01-01

The magneticGamma 1 –Gamma 4 exciton of the singlet ground state system TbP has been studied by inelastic neutron scattering above the antiferromagnetic ordering temperature. Considerable dispersion and a pronounced splitting was found in the [100] and [110] directions. Both the band width...

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

Directory of Open Access Journals (Sweden)

Natália Mariana Silva Luna

2012-09-01

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 divided 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.

On the relationship between lower extremity muscles activation and peak vertical and posterior ground reaction forces during single leg drop landing.

Science.gov (United States)

Mahaki, M; Mi'mar, R; Mahaki, B

2015-10-01

Anterior cruciate ligament (ACL) injury continues to be an important medical issue for athletes participating in sports. Vertical and posterior ground reaction forces have received considerable attention for their potential influence on ACL injuries. The purpose of this study was to examine the relationship between electromyographic activity of lower extremity muscles and the peak vertical and posterior ground reaction forces during single leg drop landing. Thirteen physical education male students participated in this correlation study. Electromyographic activities of gluteus medius, biceps femoris, medial gastrocnemius, soleus as well as anterior tibialis muscles along with ground reaction forces were measured. Participants performed single-leg landing from a 0.3 m height on to a force platform. Landing was divided into two phases: 100 ms preceding ground contact and 100 ms proceeding ground contact. Pearson correlation test was used to determine the relationships between these muscles activity and peak vertical and posterior ground reaction forces. The results of the study indicated that the activity of soleus and tibialis anterior in pre-landing phase were positively correlated with peak vertical ground reaction force ([P≤0.04], [P≤0.008], respectively). However, no significant correlation was found between the activities of other muscles in pre-landing phase and peak vertical as well as peak posterior ground reaction forces. Also, no significant correlation was found between the activities of muscles in post-landing phase and peak vertical as well as peak posterior ground reaction forces. Soleus loading shifts the proximal tibia posterior at the knee joint and tibialis anterior prevent hyperporonation of the ankle, a mechanisms of ACL injury. Hence, neuromuscular training promoting preparatory muscle activity in these muscles may reduce the incidence of ACL injuries.

A projection gradient method for computing ground state of spin-2 Bose–Einstein condensates

Energy Technology Data Exchange (ETDEWEB)

Wang, Hanquan, E-mail: hanquan.wang@gmail.com [School of Statistics and Mathematics, Yunnan University of Finance and Economics, Kunming, Yunnan Province, 650221 (China); Yunnan Tongchang Scientific Computing and Data Mining Research Center, Kunming, Yunnan Province, 650221 (China)

2014-10-01

In this paper, a projection gradient method is presented for computing ground state of spin-2 Bose–Einstein condensates (BEC). We first propose the general projection gradient method for solving energy functional minimization problem under multiple constraints, in which the energy functional takes real functions as independent variables. We next extend the method to solve a similar problem, where the energy functional now takes complex functions as independent variables. We finally employ the method into finding the ground state of spin-2 BEC. The key of our method is: by constructing continuous gradient flows (CGFs), the ground state of spin-2 BEC can be computed as the steady state solution of such CGFs. We discretized the CGFs by a conservative finite difference method along with a proper way to deal with the nonlinear terms. We show that the numerical discretization is normalization and magnetization conservative and energy diminishing. Numerical results of the ground state and their energy of spin-2 BEC are reported to demonstrate the effectiveness of the numerical method.

A projection gradient method for computing ground state of spin-2 Bose–Einstein condensates

International Nuclear Information System (INIS)

Wang, Hanquan

2014-01-01

In this paper, a projection gradient method is presented for computing ground state of spin-2 Bose–Einstein condensates (BEC). We first propose the general projection gradient method for solving energy functional minimization problem under multiple constraints, in which the energy functional takes real functions as independent variables. We next extend the method to solve a similar problem, where the energy functional now takes complex functions as independent variables. We finally employ the method into finding the ground state of spin-2 BEC. The key of our method is: by constructing continuous gradient flows (CGFs), the ground state of spin-2 BEC can be computed as the steady state solution of such CGFs. We discretized the CGFs by a conservative finite difference method along with a proper way to deal with the nonlinear terms. We show that the numerical discretization is normalization and magnetization conservative and energy diminishing. Numerical results of the ground state and their energy of spin-2 BEC are reported to demonstrate the effectiveness of the numerical method

Ground state structure of U2Mo: static and lattice dynamics study

International Nuclear Information System (INIS)

Mukherjee, D.; Sahoo, B.D.; Joshi, K.D.; Kaushik, T.C.

2016-01-01

According to experimental reports, the ground state stable structure of U 2 Mo is tetragonal. However, various theoretical studies performed in past do not get tetragonal phase as the stable structure at ambient conditions. Therefore, the ground state structure of U 2 Mo is still unresolved. In an attempt to understand the ground state properties of this system, we have carried out first principle electronic band structure calculations. The structural stability analysis carried out using evolutionary structure search algorithm in conjunction with ab-inito method shows that a hexagonal structure (space group P6/mmm) is the lowest enthalpy structure at ambient condition and remains stable upto 200 GPa. The elastic and lattice dynamical stability further supports the stability of this phase at ambient condition. Further, using the 0 K calculations in conjunction with finite temperature corrections, we have derived the isotherm and shock adiabat (Hugoniot) of this material. Various equilibrium properties such as ambient pressure volume, bulk modulus, pressure derivative of bulk modulus etc. are derived from equation of state. (author)

66Ga ground state β spectrum

DEFF Research Database (Denmark)

Severin, Gregory; Knutson, L. D.; Voytas, P. A.

2014-01-01

The ground state branch of the β decay of 66Ga is an allowed Fermi (0+ → 0+) transition with a relatively high f t value. The large f t and the isospin-forbidden nature of the transition indicates that the shape of the β spectrum of this branch may be sensitive to higher order contributions...... to the decay. Two previous measurements of the shape have revealed deviations from an allowed spectrum but disagree about whether the shape factor has a positive or negative slope. As a test of a new iron-free superconducting β spectrometer, we have measured the shape of the ground state branch of the 66Ga β...... spectrum above a positron energy of 1.9 MeV. The spectrum is consistent with an allowed shape, with the slope of the shape factor being zero to within ±3 × 10−3 per MeV. We have also determined the endpoint energy for the ground state branch to be 4.1535 ± 0.0003 (stat.) ±0.0007 (syst.) MeV, in good...

Acquisition and deconvolution of seismic signals by different methods to perform direct ground-force measurements

Science.gov (United States)

Poletto, Flavio; Schleifer, Andrea; Zgauc, Franco; Meneghini, Fabio; Petronio, Lorenzo

2016-12-01

We present the results of a novel borehole-seismic experiment in which we used different types of onshore-transient-impulsive and non-impulsive-surface sources together with direct ground-force recordings. The ground-force signals were obtained by baseplate load cells located beneath the sources, and by buried soil-stress sensors installed in the very shallow-subsurface together with accelerometers. The aim was to characterize the source's emission by its complex impedance, function of the near-field vibrations and soil stress components, and above all to obtain appropriate deconvolution operators to remove the signature of the sources in the far-field seismic signals. The data analysis shows the differences in the reference measurements utilized to deconvolve the source signature. As downgoing waves, we process the signals of vertical seismic profiles (VSP) recorded in the far-field approximation by an array of permanent geophones cemented at shallow-medium depth outside the casing of an instrumented well. We obtain a significant improvement in the waveform of the radiated seismic-vibrator signals deconvolved by ground force, similar to that of the seismograms generated by the impulsive sources, and demonstrates that the results obtained by different sources present low values in their repeatability norm. The comparison evidences the potentiality of the direct ground-force measurement approach to effectively remove the far-field source signature in VSP onshore data, and to increase the performance of permanent acquisition installations for time-lapse application purposes.

A full cost analysis of the replacement of Naval Base, Guantanamo Bay's Marine ground defense force by the fleet antiterrorism security team

OpenAIRE

Ordona, Placido C.

2000-01-01

Constrained defense budgets and manpower resources have motivated the United States Marine Corps and the United States Navy to seek initiatives that maximize the efficient use and allocation of these diminishing resources. One such initiative is the restructuring of the Marine security presence at Naval Station, Guantanamo Bay, Cuba, through the replacement of the 350 man Marine Ground Defense Force with a smaller, rotating unit consisting of two platoons from the Fleet Antiterrorism Security...

Alterations to the orientation of the ground reaction force vector affect sprint acceleration performance in team sports athletes.

Science.gov (United States)

Bezodis, Neil E; North, Jamie S; Razavet, Jane L

2017-09-01

A more horizontally oriented ground reaction force vector is related to higher levels of sprint acceleration performance across a range of athletes. However, the effects of acute experimental alterations to the force vector orientation within athletes are unknown. Fifteen male team sports athletes completed maximal effort 10-m accelerations in three conditions following different verbal instructions intended to manipulate the force vector orientation. Ground reaction forces (GRFs) were collected from the step nearest 5-m and stance leg kinematics at touchdown were also analysed to understand specific kinematic features of touchdown technique which may influence the consequent force vector orientation. Magnitude-based inferences were used to compare findings between conditions. There was a likely more horizontally oriented ground reaction force vector and a likely lower peak vertical force in the control condition compared with the experimental conditions. 10-m sprint time was very likely quickest in the control condition which confirmed the importance of force vector orientation for acceleration performance on a within-athlete basis. The stance leg kinematics revealed that a more horizontally oriented force vector during stance was preceded at touchdown by a likely more dorsiflexed ankle, a likely more flexed knee, and a possibly or likely greater hip extension velocity.

Use of a tibial accelerometer to measure ground reaction force in running: A reliability and validity comparison with force plates.

Science.gov (United States)

Raper, Damian P; Witchalls, Jeremy; Philips, Elissa J; Knight, Emma; Drew, Michael K; Waddington, Gordon

2018-01-01

The use of microsensor technologies to conduct research and implement interventions in sports and exercise medicine has increased recently. The objective of this paper was to determine the validity and reliability of the ViPerform as a measure of load compared to vertical ground reaction force (GRF) as measured by force plates. Absolute reliability assessment, with concurrent validity. 10 professional triathletes ran 10 trials over force plates with the ViPerform mounted on the mid portion of the medial tibia. Calculated vertical ground reaction force data from the ViPerform was matched to the same stride on the force plate. Bland-Altman (BA) plot of comparative measure of agreement was used to assess the relationship between the calculated load from the accelerometer and the force plates. Reliability was calculated by intra-class correlation coefficients (ICC) with 95% confidence intervals. BA plot indicates minimal agreement between the measures derived from the force plate and ViPerform, with variation at an individual participant plot level. Reliability was excellent (ICC=0.877; 95% CI=0.825-0.917) in calculating the same vertical GRF in a repeated trial. Standard error of measure (SEM) equalled 99.83 units (95% CI=82.10-119.09), which, in turn, gave a minimum detectable change (MDC) value of 276.72 units (95% CI=227.32-330.07). The ViPerform does not calculate absolute values of vertical GRF similar to those measured by a force plate. It does provide a valid and reliable calculation of an athlete's lower limb load at constant velocity. Copyright © 2017 Sports Medicine Australia. Published by Elsevier Ltd. All rights reserved.

Effects of knee extension constraint training on knee flexion angle and peak impact ground-reaction force.

Science.gov (United States)

Liu, Hui; Wu, Will; Yao, Wanxiang; Spang, Jeffrey T; Creighton, R Alexander; Garrett, William E; Yu, Bing

2014-04-01

Low compliance with training programs is likely to be one of the major reasons for inconsistency of the data regarding the effectiveness of current anterior cruciate ligament (ACL) injury prevention programs. Training methods that reduce training time and cost could favorably influence the effectiveness of ACL injury prevention programs. A newly designed knee extension constraint training device may serve this purpose. (1) Knee extension constraint training for 4 weeks would significantly increase the knee flexion angle at the time of peak impact posterior ground-reaction force and decrease peak impact ground-reaction forces during landing of a stop-jump task and a side-cutting task, and (2) the training effects would be retained 4 weeks after completion of the training program. Controlled laboratory study. Twenty-four recreational athletes were randomly assigned to group A or B. Participants in group A played sports without wearing a knee extension constraint device for 4 weeks and then played sports while wearing the device for 4 weeks, while participants in group B underwent a reversed protocol. Both groups were tested at the beginning of week 1 and at the ends of weeks 4 and 8 without wearing the device. Knee joint angles were obtained from 3-dimensional videographic data, while ground-reaction forces were measured simultaneously using force plates. Analyses of variance were performed to determine the training effects and the retention of training effects. Participants in group A significantly increased knee flexion angles and decreased ground-reaction forces at the end of week 8 (P ≤ .012). Participants in group B significantly increased knee flexion angles and decreased ground-reaction forces at the ends of weeks 4 and 8 (P ≤ .007). However, participants in group B decreased knee flexion angles and increased ground-reaction forces at the end of week 8 in comparison with the end of week 4 (P ≤ .009). Knee extension constraint training for 4 weeks

The effects of dorso-lumbar motion restriction on the ground reaction force components during running.

Science.gov (United States)

Morley, Joseph J; Traum, Edward

2016-04-01

The effects of restricting dorso-lumbar spine mobility on ground reaction forces in runners was measured and assessed. A semi-rigid cast was used to restrict spinal motion during running. Subjects ran across a force platform at 3.6 m/s, planting the right foot on the platform. Data was collected from ten running trials with the cast and ten without the cast and analysed. Casted running showed that the initial vertical heel strike maximum was increased (p running (p running results in measurable and repeatable alterations in ground reaction force components. Alterations in load transfer due to decreased spinal motion may be a factor contributing to selected injuries in runners. Copyright © 2015 Elsevier Ltd. All rights reserved.

Exact ground-state correlation functions of one-dimenisonal strongly correlated electron models with resonating-valence-bond ground state

International Nuclear Information System (INIS)

Yamanaka, Masanori; Honjo, Shinsuke; Kohmoto, Mahito

1996-01-01

We investigate one-dimensional strongly correlated electron models which have the resonating-valence-bond state as the exact ground state. The correlation functions are evaluated exactly using the transfer matrix method for the geometric representations of the valence-bond states. In this method, we only treat matrices with small dimensions. This enables us to give analytical results. It is shown that the correlation functions decay exponentially with distance. The result suggests that there is a finite excitation gap, and that the ground state is insulating. Since the corresponding noninteracting systems may be insulating or metallic, we can say that the gap originates from strong correlation. The persistent currents of the present models are also investigated and found to be exactly vanishing

Vertical ground reaction force analysis during gait with unstable shoes

Directory of Open Access Journals (Sweden)

Giulia Pereira

Full Text Available AbstractIntroduction Footwear is no longer just an accessory but also a protection for the musculoskeletal system, and its most important characteristic is comfort.Objectives This study aims to identify and to analyze the vertical ground reaction force in barefoot women and women with unstable shoes.Methodology Five women aged 25 ± 4 years old and mass of 50 ± 7 kg participated in this study. An AMTI force plate was used for data acquisition. The 10 trials for each situation were considered valid where the subject approached the platform with the right foot and at the speed of 4 km/h ± 5%. The instable shoe of this study is used in the practice of physical activity.Results The results showed that the first peak force was higher for the footwear situation, about 5% and significant differences between the barefoot and footwear situation. This significant difference was in the first and second peaks force and in the time of the second peak.Conclusion The values showed that the footwear absorbs approximately 45% of the impact during gait.

Ground beetles (Coleoptera, Carabidae of the Hanford Nuclear Site in south-central Washington State

Directory of Open Access Journals (Sweden)

Chris Looney

2014-04-01

Full Text Available In this paper we report on ground beetles (Coleoptera: Carabidae collected from the Hanford Nuclear Reservation and Hanford National Monument (together the Hanford Site, which is located in south-central Washington State. The Site is a relatively undisturbed relict of the shrub-steppe habitat present throughout much of the western Columbia Basin before the westward expansion of the United States. Species, localities, months of capture, and capture method are reported for field work conducted between 1994 and 2002. Most species were collected using pitfall traps, although other capture methods were employed. Trapping results indicate the Hanford Site supports a diverse ground beetle community, with over 90% of the 92 species captured native to North America. Four species collected during the study period are newly recorded for Washington State: Bembidion diligens Casey, Calosoma obsoletum Say, Pseudaptinus rufulus (LeConte, and Stenolophus lineola (Fabricius. Based on these data, the Site maintains a diverse ground beetle fauna and, due to its size and diversity of habitats, is an important repository of shrub-steppe biodiversity.

Effect of foot orthoses on magnitude and timing of rearfoot and tibial motions, ground reaction force and knee moment during running.

Science.gov (United States)

Eslami, Mansour; Begon, Mickaël; Hinse, Sébastien; Sadeghi, Heydar; Popov, Peter; Allard, Paul

2009-11-01

Changes in magnitude and timing of rearfoot eversion and tibial internal rotation by foot orthoses and their contributions to vertical ground reaction force and knee joint moments are not well understood. The objectives of this study were to test if orthoses modify the magnitude and time to peak rearfoot eversion, tibial internal rotation, active ground reaction force and knee adduction moment and determine if rearfoot eversion, tibial internal rotation magnitudes are correlated to peak active ground reaction force and knee adduction moment during the first 60% stance phase of running. Eleven healthy men ran at 170 steps per minute in shod and with foot orthoses conditions. Video and force-plate data were collected simultaneously to calculate foot joint angular displacement, ground reaction forces and knee adduction moments. Results showed that wearing semi-rigid foot orthoses significantly reduced rearfoot eversion 40% (4.1 degrees ; p=0.001) and peak active ground reaction force 6% (0.96N/kg; p=0.008). No significant time differences occurred among the peak rearfoot eversion, tibial internal rotation and peak active ground reaction force in both conditions. A positive and significant correlation was observed between peak knee adduction moment and the magnitude of rearfoot eversion during shod (r=0.59; p=0.04) and shod/orthoses running (r=0.65; p=0.02). In conclusion, foot orthoses could reduce rearfoot eversion so that this can be associated with a reduction of knee adduction moment during the first 60% stance phase of running. Finding implies that modifying rearfoot and tibial motions during running could not be related to a reduction of the ground reaction force.

Transonic and supersonic ground effect aerodynamics

Science.gov (United States)

Doig, G.

2014-08-01

A review of recent and historical work in the field of transonic and supersonic ground effect aerodynamics has been conducted, focussing on applied research on wings and aircraft, present and future ground transportation, projectiles, rocket sleds and other related bodies which travel in close ground proximity in the compressible regime. Methods for ground testing are described and evaluated, noting that wind tunnel testing is best performed with a symmetry model in the absence of a moving ground; sled or rail testing is ultimately preferable, though considerably more expensive. Findings are reported on shock-related ground influence on aerodynamic forces and moments in and accelerating through the transonic regime - where force reversals and the early onset of local supersonic flow is prevalent - as well as more predictable behaviours in fully supersonic to hypersonic ground effect flows.

Benefit Analysis Report, United States Air Force Technical Order Management Systems (AFTOMS)

Science.gov (United States)

1989-08-01

This report prepared by the Transportation Systems Center (TSC) concludes an analysis of the Technical Order (TO) costs and benefits, which was originally undertaken as part of the US Air Force Computer-aided Acquisition and Logistics Support (CALS) ...

Systematics of ground state multiplets of atomic nuclei in the delta-interaction approach

Energy Technology Data Exchange (ETDEWEB)

Imasheva, L. T.; Ishkhanov, B. S.; Stepanov, M. E., E-mail: stepanov@depni.sinp.msu.ru [Moscow State University, Faculty of Physics (Russian Federation); Tretyakova, T. Yu. [Moscow State University, Skobeltsyn Institute of Nuclear Physics (Russian Federation)

2015-12-15

Pairing forces between nucleons in an atomic nucleus strongly influence its structure. One of the manifestations of pair interaction is the ground state multiplet (GSM) formation in the spectrum of low-lying excited states of even–even nuclei. The value of GSM splitting is determined by the value of pair interaction of nucleons; for each isotope, it can be estimated on the basis of experimental nuclear masses. The quality of this estimate is characterized by the degree of reproduction of GSM levels in the nucleus. The GSM systematics in even–even nuclei with a pair of identical nucleons in addition to the filled nuclear core is considered on the basis of delta interaction.

Ground reaction forces of Olympic and World Championship race walkers.

Science.gov (United States)

Hanley, Brian; Bissas, Athanassios

2016-01-01

Race walking is an Olympic event where no visible loss of contact should occur and the knee must be straightened until midstance. The purpose of this study was to analyse ground reaction forces of world-class race walkers and associate them with key spatiotemporal variables. Nineteen athletes race walked along an indoor track and made contact with two force plates (1000 Hz) while being filmed using high-speed videography (100 Hz). Race walking speed was correlated with flight time (r = .46, p = .049) and flight distance (r = .69, p = .001). The knee's movement from hyperextension to flexion during late stance meant the vertical push-off force that followed midstance was smaller than the earlier loading peak (p push-off forces (r = .60, p = .011). Lower fluctuations in speed during stance were associated with higher stride frequencies (r = .69, p = .001), and highlighted the importance of avoiding too much braking in early stance. The flattened trajectory and consequential decrease in vertical propulsion might help the race walker avoid visible loss of contact (although non-visible flight times were useful in increasing stride length), while a narrow stride width was important in reducing peak forces in all three directions and could improve movement efficiency.

Ground reaction forces and kinematics in distance running in older-aged men.

Science.gov (United States)

Bus, Sicco A

2003-07-01

The biomechanics of distance running has not been studied before in older-aged runners but may be different than in younger-aged runners because of musculoskeletal degeneration at older age. This study aimed at determining whether the stance phase kinematics and ground reaction forces in running are different between younger- and older-aged men. Lower-extremity kinematics using three-dimensional motion analysis and ground reaction forces (GRF) using a force plate were assessed in 16 older-aged (55-65 yr) and 13 younger-aged (20-35 yr) well-trained male distance runners running at a self-selected (SRS) and a controlled (CRS) speed of 3.3 m.s-1. The older subjects ran at significantly lower self-selected speeds than the younger subjects (mean 3.34 vs 3.77 m.s-1). In both speed conditions, the older runners exhibited significantly more knee flexion at heel strike and significantly less knee flexion and extension range of motion. No age group differences were present in subtalar joint motion. Impact peak force (1.91 vs 1.70 BW) and maximal initial loading rate (107.5 vs 85.5 BW.s-1) were significantly higher in the older runners at the CRS. Maximal peak vertical and anteroposterior forces and impulses were significantly lower in the older runners at the SRS. The biomechanics of running is different between older- and younger-aged runners on several relevant parameters. The larger impact peak force and initial loading rate indicate a loss of shock-absorbing capacity in the older runners. This may increase their susceptibility to lower-extremity overuse injuries. Moreover, it emphasizes the focus on optimizing cushioning properties in the design and prescription of running shoes and suggests that older-aged runners should be cautious with running under conditions of high impact.

Ground reaction forces and kinematics in distance running in older-aged men

NARCIS (Netherlands)

Bus, Sicco A.

2003-01-01

Purpose: The biomechanics of distance running has not been studied before in older-aged runners but may be different than in younger-aged runners because of musculoskeletal degeneration at older age. This study aimed at determining whether the stance phase kinematics and ground reaction forces in

Exact many-electron ground states on diamond and triangle Hubbard chains

International Nuclear Information System (INIS)

Gulacsi, Zsolt; Kampf, Arno; Vollhardt, Dieter

2009-01-01

We construct exact ground states of interacting electrons on triangle and diamond Hubbard chains. The construction requires (1) a rewriting of the Hamiltonian into positive semidefinite form, (2) the construction of a many-electron ground state of this Hamiltonian, and (3) the proof of the uniqueness of the ground state. This approach works in any dimension, requires no integrability of the model, and only demands sufficiently many microscopic parameters in the Hamiltonian which have to fulfill certain relations. The scheme is first employed to construct exact ground state for the diamond Hubbard chain in a magnetic field. These ground states are found to exhibit a wide range of properties such as flat-band ferromagnetism and correlation induced metallic, half-metallic or insulating behavior, which can be tuned by changing the magnetic flux, local potentials, or electron density. Detailed proofs of the uniqueness of the ground states are presented. By the same technique exact ground states are constructed for triangle Hubbard chains and a one-dimensional periodic Anderson model with nearest-neighbor hybridization. They permit direct comparison with results obtained by variational techniques for f-electron ferromagnetism due to a flat band in CeRh 3 B 2 . (author)

Approximating the ground state of gapped quantum spin systems

Energy Technology Data Exchange (ETDEWEB)

Michalakis, Spyridon [Los Alamos National Laboratory; Hamza, Eman [NON LANL; Nachtergaele, Bruno [NON LANL; Sims, Robert [NON LANL

2009-01-01

We consider quantum spin systems defined on finite sets V equipped with a metric. In typical examples, V is a large, but finite subset of Z{sup d}. For finite range Hamiltonians with uniformly bounded interaction terms and a unique, gapped ground state, we demonstrate a locality property of the corresponding ground state projector. In such systems, this ground state projector can be approximated by the product of observables with quantifiable supports. In fact, given any subset {chi} {contained_in} V the ground state projector can be approximated by the product of two projections, one supported on {chi} and one supported on {chi}{sup c}, and a bounded observable supported on a boundary region in such a way that as the boundary region increases, the approximation becomes better. Such an approximation was useful in proving an area law in one dimension, and this result corresponds to a multi-dimensional analogue.

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 su...... 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....

Vertical ground reaction forces in patients after calcaneal trauma surgery.

Science.gov (United States)

van Hoeve, S; Verbruggen, J; Willems, P; Meijer, K; Poeze, M

2017-10-01

Vertical ground reaction forces (VGRFs) are altered in patients after foot trauma. It is not known if this correlates with ankle kinematics. The aim of this study was to analyze VGRFs in patients after calcaneal trauma and correlate them to patient-reported outcome measures (PROMs), radiographic findings and kinematic analysis, using a multi-segment foot model. In addition, we determined the predictive value of VGRFs to identify patients with altered foot kinematics. Thirteen patients (13 feet) with displaced intra-articular calcaneal fractures, were included an average of two years after trauma surgery. PROMs, radiographic findings on postoperative computed tomography scans, gait analysis using the Oxford foot model and VGRFs were analysed during gait. Results were compared with those of 11 healthy subjects (20 feet). Speed was equal in both groups, with healthy subjects walking at self-selected slow speed (0.94±0.18m/s) and patients after surgery walking at self-selected normal speed (0.94±0.29m/s). ROC curves were used to determine the predictive value. Patients after calcaneal surgery showed a lower minimum force during midstance (p=0.004) and a lower maximum force during toe-off (p=0.011). This parameter correlated significantly with the range of motion in the sagittal plane during the push-off phase (r 0.523, p=0.002), as well as with PROMs and with postoperative residual step-off (r 0.423, p=0.016). Combining these two parameters yielded a cut-off value of 193% (ppush-off correlated significantly with PROMs, range of motion in the sagittal plane during push-off and radiographic postoperative residual step-off in the posterior facet of the calcaneal bone. VGRFs are a valuable screening tool for identifying patients with altered gait patterns. Copyright © 2017 Elsevier B.V. All rights reserved.

Changes in ground reaction force during a rebound-jump task after hip strength training for single-sided ankle dorsiflexion restriction.

Science.gov (United States)

Kondo, Hitoshi; Someya, Fujiko

2016-01-01

[Purpose] Lateral ankle sprains are common injuries suffered while playing sports, and abnormal forward- and inward-directed ground reaction force occurs during a jumping task. However, the influence of hip muscle strength training on jumping performance after ankle injuries has not been fully examined. This study thus examined changes in ground reaction force during a rebound-jump task after training to strengthen hip muscles. [Subjects and Methods] Ten of 30 female high school basketball players were assigned as subjects who showed a difference of 7 or more degrees in dorsiflexion ranges between the bilateral ankles. The subjects underwent 12 weeks of training to strengthen hip abductors and external rotators. Comparisons between before and after training were made regarding ground reaction force components, hip and knee joint angles, percentage of maximum voluntary contraction in leg muscles, and muscle strength of hip muscles during the rebound-jump task. [Results] After training, the subjects showed increased strength of external rotator muscles, increased percentage of maximum voluntary contraction in the gluteus medius muscle, decreased inward ground reaction force, and increased flexion angles of the hip and knee joints. [Conclusion] This study suggests that training to strengthen hip muscles may ameliorate the inward ground reaction force in athletes with ankle dorsiflexion restriction.

Estimation of Vertical Ground Reaction Forces and Sagittal Knee Kinematics During Running Using Three Inertial Sensors

Directory of Open Access Journals (Sweden)

Frank J. Wouda

2018-03-01

Full Text Available Analysis of running mechanics has traditionally been limited to a gait laboratory using either force plates or an instrumented treadmill in combination with a full-body optical motion capture system. With the introduction of inertial motion capture systems, it becomes possible to measure kinematics in any environment. However, kinetic information could not be provided with such technology. Furthermore, numerous body-worn sensors are required for a full-body motion analysis. The aim of this study is to examine the validity of a method to estimate sagittal knee joint angles and vertical ground reaction forces during running using an ambulatory minimal body-worn sensor setup. Two concatenated artificial neural networks were trained (using data from eight healthy subjects to estimate the kinematics and kinetics of the runners. The first artificial neural network maps the information (orientation and acceleration of three inertial sensors (placed at the lower legs and pelvis to lower-body joint angles. The estimated joint angles in combination with measured vertical accelerations are input to a second artificial neural network that estimates vertical ground reaction forces. To validate our approach, estimated joint angles were compared to both inertial and optical references, while kinetic output was compared to measured vertical ground reaction forces from an instrumented treadmill. Performance was evaluated using two scenarios: training and evaluating on a single subject and training on multiple subjects and evaluating on a different subject. The estimated kinematics and kinetics of most subjects show excellent agreement (ρ>0.99 with the reference, for single subject training. Knee flexion/extension angles are estimated with a mean RMSE <5°. Ground reaction forces are estimated with a mean RMSE < 0.27 BW. Additionaly, peak vertical ground reaction force, loading rate and maximal knee flexion during stance were compared, however, no significant

Fast Preparation of Critical Ground States Using Superluminal Fronts

Science.gov (United States)

Agarwal, Kartiek; Bhatt, R. N.; Sondhi, S. L.

2018-05-01

We propose a spatiotemporal quench protocol that allows for the fast preparation of ground states of gapless models with Lorentz invariance. Assuming the system initially resides in the ground state of a corresponding massive model, we show that a superluminally moving "front" that locally quenches the mass, leaves behind it (in space) a state arbitrarily close to the ground state of the gapless model. Importantly, our protocol takes time O (L ) to produce the ground state of a system of size ˜Ld (d spatial dimensions), while a fully adiabatic protocol requires time ˜O (L2) to produce a state with exponential accuracy in L . The physics of the dynamical problem can be understood in terms of relativistic rarefaction of excitations generated by the mass front. We provide proof of concept by solving the proposed quench exactly for a system of free bosons in arbitrary dimensions, and for free fermions in d =1 . We discuss the role of interactions and UV effects on the free-theory idealization, before numerically illustrating the usefulness of the approach via simulations on the quantum Heisenberg spin chain.

Ground state energy of a polaron in a superlattice

International Nuclear Information System (INIS)

Mensah, S.Y.; Allotey, F.K.A.; Nkrumah, G.; Mensah, N.G.

2000-10-01

The ground state energy of a polaron in a superlattice was calculated using the double-time Green functions. The effective mass of the polaron along the planes perpendicular to the superlattice axis was also calculated. The dependence of the ground state energy and the effective mass along the planes perpendicular to the superlattice axis on the electron-phonon coupling constant α and on the superlattice parameters (i.e. the superlattice period d and the bandwidth Δ) were studied. It was observed that if an infinite square well potential is assumed, the ground state energy of the polaron decreases (i.e. becomes more negative) with increasing α and d, but increases with increasing Δ. For small values of α, the polaron ground state energy varies slowly with Δ, becoming approximately constant for large Δ. The effective mass along the planes perpendicular to the superlattice axis was found to be approximately equal to the mass of an electron for all typical values of α, d and Δ. (author)

Trapping cold ground state argon atoms.

Science.gov (United States)

Edmunds, P D; Barker, P F

2014-10-31

We trap cold, ground state argon atoms in a deep optical dipole trap produced by a buildup cavity. The atoms, which are a general source for the sympathetic cooling of molecules, are loaded in the trap by quenching them from a cloud of laser-cooled metastable argon atoms. Although the ground state atoms cannot be directly probed, we detect them by observing the collisional loss of cotrapped metastable argon atoms and determine an elastic cross section. Using a type of parametric loss spectroscopy we also determine the polarizability of the metastable 4s[3/2](2) state to be (7.3±1.1)×10(-39)  C m(2)/V. Finally, Penning and associative losses of metastable atoms in the absence of light assisted collisions, are determined to be (3.3±0.8)×10(-10)  cm(3) s(-1).

Correlated ground state and E2 giant resonance built on it

International Nuclear Information System (INIS)

Tohyama, Mitsuru

1995-01-01

Taking 16 O as an example of realistic nuclei, we demonstrate that a correlated ground state can be obtained as a long time solution of a time-dependent density-matrix formalism (TDDM) when the residual interaction is adiabatically treated. We also study in TDDM the E2 giant resonance of 16 O built on the correlated ground state and compare it with that built on the Hartree-Fock ground state. It is found that a spurious mixing of low frequency components seen in the latter is eliminated by using the correlated ground state. (author)

The ground state energy of a classical gas

International Nuclear Information System (INIS)

Conlon, J.G.

1983-01-01

The ground state energy of a classical gas is treated using a probability function for the position of the particles and a potential function. The lower boundary for the energy when the particle number is large is defined as ground state energy. The coulomb gas consisting of positive and negative particles is also treated (fixed and variable density case) the stability of the relativistic system is investigated as well. (H.B.)

Anomalous Ground State of the Electrons in Nano-confined Water

Science.gov (United States)

2016-06-13

Anomalous ground state of the electrons in nano -confined water G. F. Reiter1*, Aniruddha Deb2*, Y. Sakurai3, M. Itou3, V. G. Krishnan4, S. J...electronic ground state of nano -confined water must be responsible for these anomalies but has so far not been investigated. We show here for the first time...using x-ray Compton scattering and a computational model, that the ground state configuration of the valence electrons in a particular nano

Ground-state energy of the interacting Bose gas in two dimensions: An explicit construction

International Nuclear Information System (INIS)

Beane, Silas R.

2010-01-01

The isotropic scattering phase shift is calculated for nonrelativistic bosons interacting at low energies via an arbitrary finite-range potential in d space-time dimensions. Scattering on a (d-1)-dimensional torus is then considered, and the eigenvalue equation relating the energy levels on the torus to the scattering phase shift is derived. With this technology in hand, and focusing on the case of two spatial dimensions, a perturbative expansion is developed for the ground-state energy of N identical bosons which interact via an arbitrary finite-range potential in a finite area. The leading nonuniversal effects due to range corrections and three-body forces are included. It is then shown that the thermodynamic limit of the ground-state energy in a finite area can be taken in closed form to obtain the energy per particle in the low-density expansion by explicitly summing the parts of the finite-area energy that diverge with powers of N. The leading and subleading finite-size corrections to the thermodynamic limit equation of state are also computed. Closed-form results--some well known, others perhaps not--for two-dimensional lattice sums are included in an Appendix.

Ground Reaction Forces Generated During Rhythmical Squats as a Dynamic Loads of the Structure

Science.gov (United States)

Pantak, Marek

2017-10-01

Dynamic forces generated by moving persons can lead to excessive vibration of the long span, slender and lightweight structure such as floors, stairs, stadium stands and footbridges. These dynamic forces are generated during walking, running, jumping and rhythmical body swaying in vertical or horizontal direction etc. In the paper the mathematical models of the Ground Reaction Forces (GRFs) generated during squats have been presented. Elaborated models was compared to the GRFs measured during laboratory tests carried out by author in wide range of frequency using force platform. Moreover, the GRFs models were evaluated during dynamic numerical analyses and dynamic field tests of the exemplary structure (steel footbridge).

Solving satisfiability problems by the ground-state quantum computer

International Nuclear Information System (INIS)

Mao Wenjin

2005-01-01

A quantum algorithm is proposed to solve the satisfiability (SAT) problems by the ground-state quantum computer. The scale of the energy gap of the ground-state quantum computer is analyzed for the 3-bit exact cover problem. The time cost of this algorithm on the general SAT problems is discussed

Calculations of the ground state of 16O

International Nuclear Information System (INIS)

Pieper, S.C.

1989-01-01

One of the central problems in nuclear physics is the description of nuclei as systems of nucleons interacting via realistic potentials. There are two main aspects of this problem: specification of the Hamiltonian, and calculation of the ground states of nuclei with the given interaction. Realistic interactions must contain both two- and three-nucleon potentials and these potentials have a complicated non-central operator structure consisting, for example, of spin, isospin and tensor dependences. This structure results in formidable many-body problems in the computation of the ground states of nuclei. At present, reliable solutions of the Faddeev equations for the A = 3 nuclei with such interactions are routine. Recently, Carlson has made an essentially exact GFMC calculation of the He ground state using just a two-nucleon interaction, and there are reliable variational calculations for more complete potential models. Nuclear matter calculations can also be made with reasonable reliability. However, there have been very few calculations of nuclei with A > 5 using realistic interactions, and none with a modern three-nucleon interaction. In the present paper I present a new technique for variational calculations for such nuclei and apply it to the ground state of 16 O. 15 refs., 2 figs., 3 tabs

Data report: western United States

International Nuclear Information System (INIS)

Cook, J.R.; Fay, W.M.

1982-04-01

This abbreviated summary data report, presents results of ground water and stream surface sediment reconnaissance in the western United States. Surface sediment samples were collected at 67,741 sites, at a target sampling density of one site per 13 square kilometers. Ground water samples were collected at 13,979 sites, and surface water samples were collected at 2,958 sites. Neutron activaton analysis results are given for uranium and 16 other elements in sediments, and for uranium and 9 other elements in waters. Mass spectrometry results are given for helium in ground waters. Supplemental analyses of the sediments for extractable uranium and 22 other elements are given where they are available. Supplemental analyses of water samples for 33 additional elements are also reported where they are available. Analytical data and field measurements are presented in tables on microfiche. Data from ground water sites (on microfiche in pocket) include (1) water chemistry measurements (pH, conductivity, and alkalinity), (2) physical measurements where applicable (water temperature, well description, and scintillometer reading), and (3) elemental analyses (U, Al, Br Cl, Dy, F, Mg, Mn, Na, and V by neutron activation and Ag, Al, As, B, Ba, Be, Ca, Ce, Co, Cr, Cu, Fe, K, Li, Mg, Mn, Mo, Na, Nb, Ni, P, Sc, Se, Si, Sr, Th, Ti, V, Y, Zn, and Zr by spectrophotometry). Helium analyses are given for ground water

Ground reaction forces produced by two different hockey skating arm swing techniques.

Science.gov (United States)

Hayward-Ellis, Julie; Alexander, Marion J L; Glazebrook, Cheryl M; Leiter, Jeff

2017-10-01

The arm swing in hockey skating can have a positive effect on the forces produced by each skate, and the resulting velocity from each push off. The main purpose of this study was to measure the differences in ground reaction forces (GRFs) produced from an anteroposterior versus a mediolateral style hockey skating arm swing. Twenty-four elite-level female hockey players performed each technique while standing on a ground-mounted force platform, and all trials were filmed using two video cameras. Force data was assessed for peak scaled GRFs in the frontal and sagittal planes, and resultant GRF magnitude and direction. Upper limb kinematics were assessed from the video using Dartfish video analysis software, confirming that the subjects successfully performed two distinct arm swing techniques. The mediolateral arm swing used a mean of 18.38° of glenohumeral flexion/extension and 183.68° of glenohumeral abduction/adduction while the anteroposterior technique used 214.17° and 28.97° respectively. The results of this study confirmed that the mediolateral arm swing produced 37% greater frontal plane and 33% less sagittal plane GRFs than the anteroposterior arm swing. The magnitudes of the resultant GRFs were not significantly different between the two techniques; however, the mediolateral technique produced a resultant GRF with a significantly larger angle from the direction of travel (44.44°) as compared to the anteroposterior technique (31.60°). The results of this study suggest that the direction of GRFs produced by the mediolateral arm swing more closely mimic the direction of lower limb propulsion during the skating stride.

Ground Reaction Forces During Reduced Gravity Running in Parabolic Flight.

Science.gov (United States)

Cavanagh, Peter; Rice, Andrea; Glauberman, Molly; Sudduth, Amanda; Cherones, Arien; Davis, Shane; Lewis, Michael; Hanson, Andrea; Wilt, Grier

2017-08-01

Treadmills have been employed as both a form of exercise and a countermeasure to prevent changes in the musculoskeletal system on almost all NASA missions and many Russian missions since the early Space Shuttle flights. It is possible that treadmills may also be part of exercise programs on future Mars missions and that they may be a component of exercise facilities in lunar or Martian habitats. In order to determine if the ambient gravity on these destinations will provide osteogenic effects while performing exercise on a treadmill, ground reactions forces (GRFs) were measured on eight subjects (six women and two men) running at 6 mph during parabolic flight in Martian and lunar gravity conditions. On average, stride length increased as gravity decreased. The first and second peaks of the GRFs decreased by 0.156 and 0.196 bodyweights, respectively, per 1/10 g change in ambient gravity. Based on comparisons with previously measured GRF during loaded treadmill running on the International Space Station, we conclude that unloaded treadmill running under lunar and Martian conditions during exploration missions is not likely to be an osteo-protective exercise.Cavanagh P, Rice A, Glauberman M, Sudduth A, Cherones A, Davis S, Lewis M, Hanson A, Wilt G. Ground reaction forces during reduced gravity running in parabolic flight. Aerosp Med Hum Perform. 2017; 88(8):730-736.

Cloud-to-ground lightning in Portugal: patterns and dynamical forcing

Science.gov (United States)

Santos, J. A.; Reis, M. A.; Sousa, J.; Leite, S. M.; Correia, S.; Janeira, M.; Fragoso, M.

2012-03-01

An analysis of the cloud-to-ground discharges (CGD) over Portugal is carried out using data collected by a network of sensors maintained by the Portuguese Meteorological Institute for 2003-2009 (7 yr). Only cloud-to-ground flashes are considered and negative polarity CGD are largely dominant. The total number of discharges reveals a considerable interannual variability and a large irregularity in their distribution throughout the year. However, it is shown that a large number of discharges occur in the May-September period (71%), with a bimodal distribution that peaks in May and September, with most of the lightning activity recorded in the afternoon (from 16:00 to 18:00 UTC). In spring and autumn the lightning activity tends to be scattered throughout the country, whereas in summer it tends to be more concentrated over northeastern Portugal. Winter generally presents low lightning activity. Furthermore, two significant couplings between the monthly number of days with discharges and the large-scale atmospheric circulation are isolated: a regional forcing, predominantly in summer, and a remote forcing. In fact, the identification of daily lightning regimes revealed three important atmospheric conditions for triggering lightning activity: regional cut-off lows, cold troughs induced by remote low pressure systems and summertime regional low pressures at low-tropospheric levels combined with a mid-tropospheric cold trough.

GPM GROUND VALIDATION CAMPAIGN REPORTS IFLOODS V1

Data.gov (United States)

National Aeronautics and Space Administration — The GPM Ground Validation Campaign Reports IFloodS dataset consists of various reports filed by the scientists during the GPM Ground Validation Iowa Flood Studies...

Task force report on health effects assessment

International Nuclear Information System (INIS)

Anderson, C.; Hushon, J.

1978-08-01

From April to August, 1978 MITRE supported the Health Effects Assessment Task Force sponsored by the Office of the Assistant Secretary for the Environment at DOE. The findings of that Task Force are incorporated in this report and include a detailed definition of health effects assessment, a survey of the mandates for health effects assessments within DOE/EV, a review of current DOE-EV health effects assessment activities, an analysis of the constraints affecting the health effects assessment process and a discussion of the Task Force recommendations. Included as appendices are summaries of two workshops conducted by the Task Force to determine the state-of-the-art of health effects assessment and modeling and a review of risk assessment activities in other federal agencies. The primary recommendation of the panel was that an office be designated or created under the Office of the Assistant Secretary for the Environment to coordinate the Health Effects Risk Assessment effort covering up to 40 program and policy areas; a similar need was expressed for the environmental effects assessment area. 1 tab

Influence of mass-asymmetry and ground state spin on fission fragment angular distributions

International Nuclear Information System (INIS)

Thomas, R.G.; Biswas, D.C.; Saxena, A.; Pant, L.M.; Nayak, B.K.; Vind, R.P.; Sahu, P.K.; Sinha, Shrabani; Choudhury, R.K.

2001-01-01

The strong influence of the target or/and projectile ground state spin on the anomalously large anisotropies of fission fragments produced in the heavy-ion induced fission of actinide targets were reported earlier. Interestingly, all those systems studied were having a mass asymmetry greater than the Businaro-Gallone critical asymmetry and hence the presence of pre-equilibrium fission was unambiguously ruled out. The observed anisotropies were successfully explained using the ECD-K-States model. It is of interest to know the influence of the target/projectile ground state spin on systems having an entrance channel mass asymmetry less than the critical value where pre-equilibrium fission cannot be ignored. With this motivation we performed measurements of fission fragment angular distributions of the 16 O+ 235 U (spin=7/2) system

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.)

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

International Nuclear Information System (INIS)

Raabe, Christian

2008-01-01

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.)

Ground reaction force characteristics of Tai Chi push hand.

Science.gov (United States)

Chang, Yao-Ting; Chang, Jia-Hao; Huang, Chen-Fu

2014-01-01

Push Hand is an advanced training technique for the Yang-style old frame 108 forms Tai Chi Chuan. It is performed by two practitioners. To clarify how people use forces during Push Hand training, it is important to review the ground reaction force (GRF). Here, we quantify the characteristics of the GRF during Push Hand training. Kinematic data and GRF data from 10 Tai Chi Chuan practitioners (29.9 ± 7.87 years) were synchronously recorded using a three-dimensional motion analysis system (200 frames · s(-1)) and three-dimensional force plates (1000 Hz). The resultant GRF for both feet for the 0%, 50% and 100% phases of attack and defence were compared to body weight using a paired-samples t-test. The differences in the resultant GRF between the 0%, 50% and 100% phases of attack and defence were tested by one-way repeated-measures ANOVA. The significance level was set to 0.05. The total resultant GRF was almost equal to the participant's body weight in push hand. This result was consistent throughout the entire push hand process. Our results revealed that the GRF was comparable to the body weight, implying that practitioners do not push or resist their opponents during the push hand process.

Structural instability and ground state of the U_2Mo compound

International Nuclear Information System (INIS)

Losada, E.L.; Garcés, J.E.

2015-01-01

This work reports on the structural instability at T = 0 °K of the U_2Mo compound in the C11_b structure under the distortion related to the C_6_6 elastic constant. The electronic properties of U_2Mo such as density of states (DOS), bands and Fermi surface (FS) are studied to understand the source of the instability. The C11_b structure can be interpreted as formed by parallel linear chains along the z-directions each one composed of successive U–Mo–U blocks. Hybridization due to electronic interactions inside the U–Mo–U blocks is slightly modified under the D_6 distortion. The change in distance between chains modifies the U–U interaction and produces a split of f-states. The distorted structure is stabilized by a decrease in energy of the hybridized states, mainly between d-Mo and f-U states, together with the f-band split. Consequently, an induced Peierls distortion is produced in U_2Mo due to the D_6 distortion. It is important to note that the results of this work indicate that the structure of the ground state of the U_2Mo compound is not the assumed C11_b structure. It is suggested for the ground state a structure with hexagonal symmetry (P6 #168), ∼0.1 mRy below the energy of the recently proposed Pmmn structure. - Highlights: • Structural instability of the C11b compound due to the D6 deformation. • Induced Peierls distortion due to the D6 deformation. • Distorted structure is stabilized by hybridization and split of f-Uranium state. • P6 (#168) suggested ground state for the U_2Mo compound.

Task Force report

International Nuclear Information System (INIS)

Anon.

1987-01-01

The International Task Force on Prevention of Nuclear Terrorism was formed in 1985 under the auspices of the Nuclear Control Institute. This report is a consensus report of the 26 task force members - all members not necessarily agreeing on every point and all wordings, but in each case a substantial majority did agree. First, the report defines the threat, then establishes the priorities. Short-term recommendations are presented on: (1) protecting nuclear weapons; (2) protecting nuclear materials; (3) protecting nuclear facilities; (4) intelligence programs; (5) civil liberties concerns; (6) controlling nuclear transfers; (7) US - Soviet cooperation; (8) arms control initiatives; (9) convention of physical protection of nuclear material; (10) role of emergency management programs; and (11) role of the media. Brief long-term recommendations are included on (1) international measures, and (2) emerging nuclear technologies. An Appendix, Production of Nuclear Materials Usable in Weapons is presented for further consideration (without recommendations)

Ground state phase diagram of extended attractive Hubbard model

International Nuclear Information System (INIS)

Robaszkiewicz, S.; Chao, K.A.; Micnas, R.

1980-08-01

The ground state phase diagram of the extended Hubbard model with intraatomic attraction has been derived in the Hartree-Fock approximation formulated in terms of the Bogoliubov variational approach. For a given value of electron density, the nature of the ordered ground state depends essentially on the sign and the strength of the nearest neighbor coupling. (author)

Extended random-phase approximation with three-body ground-state correlations

International Nuclear Information System (INIS)

Tohyama, M.; Schuck, P.

2008-01-01

An extended random-phase approximation (ERPA) which contains the effects of ground-state correlations up to a three-body level is applied to an extended Lipkin model which contains an additional particle-scattering term. Three-body correlations in the ground state are necessary to preserve the hermiticity of the Hamiltonian matrix of ERPA. Two approximate forms of ERPA which neglect the three-body correlations are also applied to investigate the importance of three-body correlations. It is found that the ground-state energy is little affected by the inclusion of the three-body correlations. On the contrary, three-body correlations for the excited states can become quite important. (orig.)

Final task force report on the Agreement State Program

International Nuclear Information System (INIS)

1977-12-01

Section 274 of the Atomic Energy Act provides a statutory means by which the U.S. Nuclear Regulatory Commission may relinquish to the States a part of its regulatory authority over the use of source material, by-product material, and small quantities of special nuclear material. The Commission is required to retain regulatory authority over the licensing of nuclear facilities, exports and imports of nuclear materials and facilities, larger quantities of special nuclear material, and activities conducted by other Federal agencies which are not exempted by the Act. This study analyzes the NRC Agreement State Program to determine: whether the NRC should aggressively promote Agreement State status; whether the NRC should relinquish additional responsibility to the States and if so, which responsibilities and under what circumstances, and conversely if NRC should reassert authority in any areas; to what extent the NRC should continue to oversee State performance; and whether changes in the statute or regulations are desirable or required. At present, there are 25 states that have not opted for agreement status. Appendix A contains a discussion of the legislative history of Section 274, a report on the current status of the program, Agreement State review procedures, the full text of Section 274, a list of Agreement States, dates of agreements, number of licenses, a list of non-Agreement States, and numbers of NRC licenses in these States. Appendix B analyzes states' comments

Ground reaction forces and knee mechanics in the weight acceptance phase of a dance leap take-off and landing.

Science.gov (United States)

Kulig, Kornelia; Fietzer, Abbigail L; Popovich, John M

2011-01-01

Aesthetic constraints allow dancers fewer technique modifications than other athletes to negotiate the demands of leaping. We examined vertical ground reaction force and knee mechanics during a saut de chat performed by healthy dancers. It was hypothesized that vertical ground reaction force during landing would exceed that of take-off, resulting in greater knee extensor moments and greater knee angular stiffness. Twelve dancers (six males, six females; age 18.9 ± 1.2 years, mass 59.2 ± 9.5 kg, height 1.68 ± 0.08 m, dance training 8.9 ± 5.1 years) with no history of low back pain or lower extremity pathology participated in the study. Saut de chat data were captured using an eight-camera Vicon system and AMTI force platforms. Peak ground reaction force was 26% greater during the landing phase, but did not result in increased peak knee extensor moments. Taking into account the 67% greater knee angular displacement during landing, this resulted in less knee angular stiffness during landing. In conclusion, landing was accomplished with less knee angular stiffness despite the greater peak ground reaction force. A link between decreased joint angular stiffness and increased soft tissue injury risk has been proposed elsewhere; therefore, landing from a saut de chat may be more injurious to the knee soft tissue than take-off.

Instances of Use of United States Armed Forces Abroad, 1798-2014

Science.gov (United States)

2014-09-15

Garcia, and Thomas J. Nicola . Instances of Use of United States Armed Forces Abroad, 1798-2014 Congressional Research Service Contents...landing zones near the U.S. Embassy in Saigon and the Tan Son Nhut Airfield. Mayaguez incident. On May 15, 1975, President Ford reported he had ordered...Report R41989, Congressional Authority to Limit Military Operations, by Jennifer K. Elsea, Michael John Garcia and Thomas J. Nicola . CRS Report R43344

Factors that influence ground reaction force profiles during counter movement jumping.

Science.gov (United States)

Eagles, Alexander N; Sayers, Mark G; Lovell, Dale I

2017-05-01

The purpose of this study was to examine how hip, knee and ankle kinetics and kinematics influence effective impulse production during countermovement jumps. Eighteen semi-professional soccer players (22.8±2.2 years) volunteered to participate in the study. Participants completed three maximal countermovement jumps on two force platforms (1000 Hz) that were linked to a nine camera infrared motion capture system (500 Hz). Kinetic and kinematic data revealed jumpers who fail to achieve uniform ground reaction force curves that result in optimal impulse production during their jump always display hip adduction and or hip internal rotation during the concentric phase of the countermovement jump. The variation of hip adduction and or internal rotation likely represents failed joint transition during the concentric phase of the countermovement jump and appears to account for a non-uniform force trace seen in these jumpers. The findings suggest rehabilitation and conditioning exercises for injury prevention and performance may benefit from targeting frontal and transverse plane movement.

External Load Affects Ground Reaction Force Parameters Non-uniformly during Running in Weightlessness

Science.gov (United States)

DeWitt, John; Schaffner, Grant; Laughlin, Mitzi; Loehr, James; Hagan, R. Donald

2004-01-01

Long-term exposure to microgravity induces detrimefits to the musculcskdetal system (Schneider et al., 1995; LeBlanc et al., 2000). Treadmill exercise is used onboard the International Space Station as an exercise countermeasure to musculoskeletal deconditioning due to spaceflight. During locomotive exercise in weightlessness (0G), crewmembers wear a harness attached to an external loading mechanism (EL). The EL pulls the crewmember toward the treadmill, and provides resistive load during the impact and propulsive phases of gait. The resulting forces may be important in stimulating bone maintenance (Turner, 1998). The EL can be applied via a bungee and carabineer clip configuration attached to the harness and can be manipulated to create varying amounts of load levels during exercise. Ground-based research performed using a vertically mounted treadmill found that peak ground reaction forces (GRF) during running at an EL of less than one body weight (BW) are less than those that occur during running in normal gravity (1G) (Davis et al., 1996). However, it is not known how the GRF are affected by the EL in a true OG environment. Locomotion while suspended may result in biomechanics that differ from free running. The purpose of this investigation was to determine how EL affects peak impact force, peak propulsive force, loading rate, and impulse of the GRF during running in 0G. It was hypothesized that increasing EL would result in increases in each GRF parameter.

Report of the Task Force on bonding and perpetual care of nuclear licensed activities

International Nuclear Information System (INIS)

Snellings, D.D. Jr.

1975-01-01

The primary concern was to consider the bonding and perpetual care requirements of state-licensed shallow land burial sites used for the disposal of radioactive wastes. The specific charge of the task force was to examine in detail the requirements for establishing bonding and perpetual care programs for all types of licensed nuclear activities and to report the findings of the task force as guidance to assist states in program development. Goals and recommendations of the task force are discussed

State of Art Report for the OECD-NEA Loss-of-Forced Cooling (LOFC) Test Project using HTTR Reactor

International Nuclear Information System (INIS)

Jun, Ji Su

2011-05-01

The OECD/NEA Project is planned to perform the LOFC (Loss Of Forced Cooling) test using the HTTR (High Temperature engineering Test Reactor) in Japan from 31 March 2011 to 31 March 2013 in order to obtain the data for the code validation of the VHTR safety analysis. Based on the Project Agreement Document, this report gives a description of the HTTR-LOFC test, HTTR test facility, project schedule and deliverable items as the technical state art of the project, and appends the full translation of the project agreement articles on the project management

Childhood Obesity Task Forces Established by State Legislatures, 2001-2010

Science.gov (United States)

Kim, Sonia A.; Sherry, Bettylou; Blanck, Heidi M.

2013-01-01

Introduction States and communities are considering policy and environmental strategies, including enacting legislation, to reduce and prevent childhood obesity. One legislative approach has been to create task forces to understand key issues and develop a course of action. The goal of this study was to describe state-level, childhood obesity task forces in the United States created by legislation from 2001 through 2010. Methods We used the Center for Disease Control and Prevention’s Division of Nutrition, Physical Activity, and Obesity database to identify state-level childhood obesity task forces created through legislation from 2001 through 2010. Results We identified 21 states that had enacted legislation creating childhood obesity task forces of which 6 had created more than one task force. Most task forces were charged with both gathering and reviewing information and making recommendations for obesity-prevention actions in the state. Most legislation required that task forces include representation from the state legislature, state agencies, community organizations, and community members. Conclusion Evaluation of the effectiveness of obesity-prevention task forces and the primary components that contribute to their success may help to determine the advantages of the use of such strategies in obesity prevention. PMID:23987250

Hylleraas-Configuration Interaction study of the 1S ground state of the negative Li ion.

Science.gov (United States)

Sims, James S

2017-12-28

In a previous work Sims and Hagstrom [J. Chem. Phys. 140, 224312 (2014)] reported Hylleraas-Configuration Interaction (Hy-CI) method variational calculations for the neutral atom and positive ion 1 S ground states of the beryllium isoelectronic sequence. The Li - ion, nominally the first member of this series, has a decidedly different electronic structure. This paper reports the results of a large, comparable calculation for the Li - ground state to explore how well the Hy-CI method can represent the more diffuse L shell of Li - which is representative of the Be(2sns) excited states as well. The best non-relativistic energy obtained was -7.500 776 596 hartree, indicating that 10 - 20 nh accuracy is attainable in Hy-CI and that convergence of the r 12 r 34 double cusp is fast and that this correlation type can be accurately represented within the Hy-CI model.

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

Energy Technology Data Exchange (ETDEWEB)

1992-03-01

An environmental investigation of ground water conditions has been undertaken at Wright-Patterson Air Force Base (WPAFB), Ohio to obtain data to assist in the evaluation of a potential removal action to prevent, to the extent practicable, migration of the contaminated ground water across Base boundaries. Field investigations were limited to the central section of the southwestern boundary of Area C and the Springfield Pike boundary of Area B. Further, the study was limited to a maximum depth of 150 feet below grade. Three primary activities of the field investigation were: (1) installation of 22 monitoring wells, (2) collection and analysis of ground water from 71 locations, (3) measurement of ground water elevations at 69 locations. Volatile organic compounds including trichloroethylene, perchloroethylene, and/or vinyl chloride were detected in concentrations exceeding Maximum Contaminant Levels (MCL) at three locations within the Area C investigation area. Ground water at the Springfield Pike boundary of Area B occurs in two primary units, separated by a thicker-than-expected clay layers. One well within Area B was determined to exceed the MCL for trichloroethylene.

Magnetostriction-driven ground-state stabilization in 2H perovskites

International Nuclear Information System (INIS)

Porter, D. G.; Senn, M. S.; University of Oxford; Khalyavin, D. D.; Cortese, A.

2016-01-01

In this paper, the magnetic ground state of Sr_3ARuO_6, with A =(Li,Na), is studied using neutron diffraction, resonant x-ray scattering, and laboratory characterization measurements of high-quality crystals. Combining these results allows us to observe the onset of long-range magnetic order and distinguish the symmetrically allowed magnetic models, identifying in-plane antiferromagnetic moments and a small ferromagnetic component along the c axis. While the existence of magnetic domains masks the particular in-plane direction of the moments, it has been possible to elucidate the ground state using symmetry considerations. We find that due to the lack of local anisotropy, antisymmetric exchange interactions control the magnetic order, first through structural distortions that couple to in-plane antiferromagnetic moments and second through a high-order magnetoelastic coupling that lifts the degeneracy of the in-plane moments. Finally, the symmetry considerations used to rationalize the magnetic ground state are very general and will apply to many systems in this family, such as Ca_3ARuO_6, with A = (Li,Na), and Ca_3LiOsO_6 whose magnetic ground states are still not completely understood.

Auxiliary-cavity-assisted ground-state cooling of an optically levitated nanosphere in the unresolved-sideband regime

Science.gov (United States)

Feng, Jin-Shan; Tan, Lei; Gu, Huai-Qiang; Liu, Wu-Ming

2017-12-01

We theoretically analyze the ground-state cooling of an optically levitated nanosphere in the unresolved-sideband regime by introducing a coupled high-quality-factor cavity. On account of the quantum interference stemming from the presence of the coupled cavity, the spectral density of the optical force exerting on the nanosphere gets changed and then the symmetry between the heating and the cooling processes is broken. Through adjusting the detuning of a strong-dissipative cavity mode, one obtains an enhanced net cooling rate for the nanosphere. It is illustrated that the ground-state cooling can be realized in the unresolved sideband regime even if the effective optomechanical coupling is weaker than the frequency of the nanosphere, which can be understood by the picture that the effective interplay of the nanosphere and the auxiliary cavity mode brings the system back to an effective resolved regime. Besides, the coupled cavity refines the dynamical stability of the system.

The states/BC oil spill task force - an international model for formulating and influencing public policy

International Nuclear Information System (INIS)

Neel, J.; Bones, J.; Dimmick, E.; Kent, L.J.T.; Dunstan, R.; Sutherland, B.

1993-01-01

The States/British Columbia Oil Spill Task Force was established in 1989 to enhance spill coordination among the West Coast states and British Columbia, and to address a number of issues that became apparent during the Nestucca barge and Exxon Valdez oil spills. Task Force members are the directors of the oil spill prevention and response agencies in Alaska, British Columbia, California, Oregon, and Washington. The Task Force has become a national model for facilitating cooperation and building consensus between coastal states and provinces and their federal governments. In October of 1990, the task force issued a report containing a comprehensive set of recommendations addressing oil spill prevention, preparedness, and response. The group had achieved remarkable consensus, and many of the report's recommendations have been included in recent legislation enacted by the member states. The success of the task force's approach to regional coordination has also reduced the need for a proposed Pacific Oceans Resources Interstate Compact, which has been proposed to expand the states' role in areas of regulation that are otherwise federally preempted. The task force has become an effective mechanism for developing vigorous, productive relationships between government agencies, industry, and the public in both the United States and Canada. It has created important linkages between state provincial antifederal regulatory activities; for example, by providing input to Coast Guard and EPA rulemaking that implemented the Oil Pollution Act of 1990. The task force is continuing to advance its goals of promoting public policy on oil spill prevention; cooperative management of major spills by government and industry; protection of the states provincial rights and their natural and economic resources; and inter-governmental consistency in regulations adopted for oil spill prevention, contingency planning, and resource damage assessment

The relation between the (N) and (N-1) electrons atomic ground state

International Nuclear Information System (INIS)

Briet, P.

1984-05-01

The relation between the ground state of an N and (N-1) electrons atomic system are studied. We show that in some directions of the configuration space, the ratio of the N electrons atomic ground state to the one particle density is asymptotically equivalent to the (N-1) electrons atomic ground state

Degenerate ground states and multiple bifurcations in a two-dimensional q-state quantum Potts model.

Science.gov (United States)

Dai, Yan-Wei; Cho, Sam Young; Batchelor, Murray T; Zhou, Huan-Qiang

2014-06-01

We numerically investigate the two-dimensional q-state quantum Potts model on the infinite square lattice by using the infinite projected entangled-pair state (iPEPS) algorithm. We show that the quantum fidelity, defined as an overlap measurement between an arbitrary reference state and the iPEPS ground state of the system, can detect q-fold degenerate ground states for the Z_{q} broken-symmetry phase. Accordingly, a multiple bifurcation of the quantum ground-state fidelity is shown to occur as the transverse magnetic field varies from the symmetry phase to the broken-symmetry phase, which means that a multiple-bifurcation point corresponds to a critical point. A (dis)continuous behavior of quantum fidelity at phase transition points characterizes a (dis)continuous phase transition. Similar to the characteristic behavior of the quantum fidelity, the magnetizations, as order parameters, obtained from the degenerate ground states exhibit multiple bifurcation at critical points. Each order parameter is also explicitly demonstrated to transform under the Z_{q} subgroup of the symmetry group of the Hamiltonian. We find that the q-state quantum Potts model on the square lattice undergoes a discontinuous (first-order) phase transition for q=3 and q=4 and a continuous phase transition for q=2 (the two-dimensional quantum transverse Ising model).

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

Coherent Control of Ground State NaK Molecules

Science.gov (United States)

Yan, Zoe; Park, Jee Woo; Loh, Huanqian; Will, Sebastian; Zwierlein, Martin

2016-05-01

Ultracold dipolar molecules exhibit anisotropic, tunable, long-range interactions, making them attractive for the study of novel states of matter and quantum information processing. We demonstrate the creation and control of 23 Na40 K molecules in their rovibronic and hyperfine ground state. By applying microwaves, we drive coherent Rabi oscillations of spin-polarized molecules between the rotational ground state (J=0) and J=1. The control afforded by microwave manipulation allows us to pursue engineered dipolar interactions via microwave dressing. By driving a two-photon transition, we are also able to observe Ramsey fringes between different J=0 hyperfine states, with coherence times as long as 0.5s. The realization of long coherence times between different molecular states is crucial for applications in quantum information processing. NSF, AFOSR- MURI, Alfred P. Sloan Foundation, DARPA-OLE

Experimental Insights into Ground-State Selection of Quantum XY Pyrochlores

Science.gov (United States)

Hallas, Alannah M.; Gaudet, Jonathan; Gaulin, Bruce D.

2018-03-01

Extensive experimental investigations of the magnetic structures and excitations in the XY pyrochlores have been carried out over the past decade. Three families of XY pyrochlores have emerged: Yb2B2O7, Er2B2O7, and, most recently, [Formula: see text]Co2F7. In each case, the magnetic cation (either Yb, Er, or Co) exhibits XY anisotropy within the local pyrochlore coordinates, a consequence of crystal field effects. Materials in these families display rich phase behavior and are candidates for exotic ground states, such as quantum spin ice, and exotic ground-state selection via order-by-disorder mechanisms. In this review, we present an experimental summary of the ground-state properties of the XY pyrochlores, including evidence that they are strongly influenced by phase competition. We empirically demonstrate the signatures for phase competition in a frustrated magnet: multiple heat capacity anomalies, suppressed TN or TC, sample- and pressure-dependent ground states, and unconventional spin dynamics.

The solar forcing on the 7Be-air concentration variability at ground level

International Nuclear Information System (INIS)

Talpos, Simona

2004-01-01

This paper analyses the correlation between the temporal and spatial variability of 7 Be-air concentration at ground level and the amount of precipitation. There were used the measured data from 26 stations distributed on North America, South America, Australia and Antarctica. The variability study was made using EOF and principal components analysis. The presented results show that the variability of 7 Be air concentration at ground level is simultaneously influenced by the solar cycle and some atmospheric processes like precipitation, turbulent transport, advection, etc. The solar forcing on the 7 Be variability at ground level was outlined for time-scales longer than 1 year and can be considered a global phenomenon. The atmospheric processes influence the 7 Be variability for scale shorter than one year and can be considered a local phenomenon. (author)

Ground-Based Midcourse Defense (GMD) Initial Defensive Operations Capability (IDOC) at Vandenberg Air Force Base Environmental Assessment

Science.gov (United States)

2003-08-28

Zielinski , EDAW, Inc., concerning utilities supply and demand for Vandenberg Air Force Base, 1 August. Rush, P., 2002. Personal communication between...Pernell W. Rush, Technical Sergeant, Water Utilities/Water Treatment NCO, USAF 30th CES/CEOIU, Vandenberg Air Force Base, and James E. Zielinski ... Dave Savinsky, Environmental Consultant, 30 CES/CEVC, Vandenberg Air Force Base, on the Preliminary Draft Ground-Based Midcourse Defense (GMD

Hydrogeology of the 200 Areas low-level burial grounds: An interim report: Volume 1, Text

Energy Technology Data Exchange (ETDEWEB)

Last, G.V.; Bjornstad, B.N.; Bergeron, M.P.; Wallace, D.W.; Newcomer, D.R.; Schramke, J.A.; Chamness, M.A.; Cline, C.S.; Airhart, S.P.; Wilbur, J.S.

1989-01-01

This report presents information derived from the installation of 35 ground-water monitoring wells around six low-level radioactive/hazardous waste burial grounds located in the 200 Areas of the Hanford Site in southeastern Washington State. This information was collected between May 20, 1987 and August 1, 1988. The contents of this report have been divided into two volumes. This volume contains the main text. Volume 2 contains the appendixes, including data and supporting information that verify content and results found in the main text. This report documents information collected by the Pacific Northwest Laboratory at the request of Westinghouse Hanford Company. Presented in this report are the preliminary interpretations of the hydrogeologic environment of six low-level burial grounds, which comprise four waste management areas (WMAs) located in the 200 Areas of the Hanford Site. This information and its accompanying interpretations were derived from sampling and testing activities associated with the construction of 35 ground-water monitoring wells as well as a multitude of previously existing boreholes. The new monitoring wells were installed as part of a ground-water monitoring program initiated in 1986. This ground-water monitoring program is based on requirements for interim status facilities in compliance with the Resource Conservation and Recovery Act (1976).

Ground reaction forces and knee kinetics during single and repeated badminton lunges.

Science.gov (United States)

Lam, Wing Kai; Ding, Rui; Qu, Yi

2017-03-01

Repeated movement (RM) lunge that frequently executed in badminton might be used for footwear evaluation. This study examined the influence of single movement (SM) and RM lunges on the ground reaction forces (GRFs) and knee kinetics during the braking phase of a badminton lunge step. Thirteen male university badminton players performed left-forward lunges in both SM and RM sessions. Force platform and motion capturing system were used to measure GRFs and knee kinetics variables. Paired t-test was performed to determine any significant differences between SM and RM lunges regarding mean and coefficient of variation (CV) in each variable. The kinetics results indicated that compared to SM lunges, the RM lunges had shorter contact time and generated smaller maximum loading rate of impact force, peak knee anterior-posterior force, and peak knee sagittal moment but generated larger peak horizontal resultant forces (Ps < 0.05). Additionally, the RM lunges had lower CV for peak knee medial-lateral and vertical forces (Ps < 0.05). These results suggested that the RM testing protocols had a distinct loading response and adaptation pattern during lunge and that the RM protocol showed higher within-trial reliability, which may be beneficial for the knee joint loading evaluation under different interventions.

Radon concentrations in ground and drinking water in the state of Chihuahua, Mexico

International Nuclear Information System (INIS)

Villalba, L.; Colmenero Sujo, L.; Montero Cabrera, M.E.; Cano Jimenez, A.; Renteria Villalobos, M.; Delgado Mendoza, C.J.; Jurado Tenorio, L.A.; Davila Rangel, I.; Herrera Peraza, E.F.

2005-01-01

This paper reports 222 Rn concentrations in ground and drinking water of nine cities of Chihuahua State, Mexico. Fifty percent of the 114 sampled wells exhibited 222 Rn concentrations exceeding 11 Bq/L, the maximum contaminant level (MCL) recommended by the USEPA. Furthermore, around 48% (123 samples) of the tap-water samples taken from 255 dwellings showed radon concentrations over the MCL. There is an apparent correlation between total dissolved solids and radon concentration in ground-water. The high levels of 222 Rn found may be entirely attributed to the nature of aquifer rocks

Radon concentrations in ground and drinking water in the state of Chihuahua, Mexico.

Science.gov (United States)

Villalba, L; Colmenero Sujo, L; Montero Cabrera, M E; Cano Jiménez, A; Rentería Villalobos, M; Delgado Mendoza, C J; Jurado Tenorio, L A; Dávila Rangel, I; Herrera Peraza, E F

2005-01-01

This paper reports (222)Rn concentrations in ground and drinking water of nine cities of Chihuahua State, Mexico. Fifty percent of the 114 sampled wells exhibited (222)Rn concentrations exceeding 11Bq/L, the maximum contaminant level (MCL) recommended by the USEPA. Furthermore, around 48% (123 samples) of the tap-water samples taken from 255 dwellings showed radon concentrations over the MCL. There is an apparent correlation between total dissolved solids and radon concentration in ground-water. The high levels of (222)Rn found may be entirely attributed to the nature of aquifer rocks.

Estimation of ground reaction forces and moments during gait using only inertial motion capture

NARCIS (Netherlands)

Karatsidis, Angelos; Bellusci, Giovanni; Schepers, H. Martin; de Zee, Mark; Andersen, Michael S.; Veltink, Petrus H.

Ground reaction forces and moments (GRF&M) are important measures used as input in biomechanical analysis to estimate joint kinetics, which often are used to infer information for many musculoskeletal diseases. Their assessment is conventionally achieved using laboratory-based equipment that cannot

Impact Force Applied on the Spent Nuclear Fuel Disposal Canister that Accidentally Drops and Collides onto the Ground

International Nuclear Information System (INIS)

Kwon, Young Joo

2016-01-01

In this paper, a mathematical methodology was theoretically studied to obtain the impact force caused by the collision between rigid bodies. This theoretical methodology was applied to compute the impact force applied on the spent nuclear fuel disposal canister that accidentally drops and collides onto the ground. From this study, the impact force required to ensure a structurally safe canister design was theoretically formulated. The main content of the theoretical study concerns the rigid body kinematics and equation of motion during collision between two rigid bodies. On the basis of this study, a general impact theory to compute the impact force caused by the collision between two bodies was developed. This general impact theory was applied to theoretically formulate the approximate mathematical solution of the impact force that affects the spent nuclear fuel disposal canister that accidentally falls to the ground. Simultaneously, a numerical analysis was performed using the computer code to compute the numerical solution of the impact force, and the numerical result was compared with the approximate mathematical solution

Ground state of charged Base and Fermi fluids in strong coupling

International Nuclear Information System (INIS)

Mazighi, R.

1982-03-01

The ground state and excited states of the charged Bose gas were studied (wave function, equation of state, thermodynamics, application of Feynman theory). The ground state of the charged Fermi gas was also investigated together with the miscibility of charged Bose and Fermi gases at 0 deg K (bosons-bosons, fermions-bosons and fermions-fermions) [fr

Effect of uniaxial stress on the acceptor ground state and on the hopping conduction in p-type germanium and silicon

International Nuclear Information System (INIS)

Buczko, R.; Chroboczek, J.A.

1983-08-01

We constructed variational wave functions, with correct asymptotic behaviour, for the ground state of shallow acceptors in Ge and Si, utilizing the spherical tensor representation of the effective mass hamiltonian of Baldereschi and Lipari (1973), at uniaxial stress, X, resulting from the application of a tensile or compressive force along the [001] orientation (respectively X 0). Energies of the components of the ground state, computed variationally, account very well for the X-induced displacements of the binding energies and the stress splitting of shallow acceptors in both Ge and Si, at X>0 (no data for X 0. However, they account only qualitatively for the rho(X) data available for Si (X>0 only), probably because of a larger chemical shift of the acceptor ground state in Si and its possible variation with X. At larger acceptor concentrations rho(X) decreases, at large X, much stronger than predicted for both Ge and Si. We attribute this discrepancy to the increase of the contribution to electron transport of multiple hopping transitions at large X values. (author)

Theory of ground state factorization in quantum cooperative systems.

Science.gov (United States)

Giampaolo, Salvatore M; Adesso, Gerardo; Illuminati, Fabrizio

2008-05-16

We introduce a general analytic approach to the study of factorization points and factorized ground states in quantum cooperative systems. The method allows us to determine rigorously the existence, location, and exact form of separable ground states in a large variety of, generally nonexactly solvable, spin models belonging to different universality classes. The theory applies to translationally invariant systems, irrespective of spatial dimensionality, and for spin-spin interactions of arbitrary range.

Antibonding hole ground state in InAs quantum dot molecules

Energy Technology Data Exchange (ETDEWEB)

Planelles, Josep [Departament de Química Física i Analítica, Universitat Jaume I, E-12080, Castelló (Spain)

2015-01-22

Using four-band k⋅p Hamiltonians, we study how strain and position-dependent effective masses influence hole tunneling in vertically coupled InAs/GaAs quantum dots. Strain reduces the tunneling and hence the critical interdot distance required for the ground state to change from bonding to antibonding. Variable mass has the opposite effect and a rough compensation leaves little affected the critical bonding-to-antibonding ground state crossover. An alternative implementation of the magnetic field in the envelope function Hamiltonian is given which retrieves the experimental denial of possible after growth reversible magnetically induced bonding-to-antibonding ground state transition, predicted by the widely used Luttinger-Kohn Hamiltonian.

Does shoe heel design influence ground reaction forces and knee moments during maximum lunges in elite and intermediate badminton players?

Directory of Open Access Journals (Sweden)

Wing-Kai Lam

Full Text Available Lunge is one frequently executed movement in badminton and involves a unique sagittal footstrike angle of more than 40 degrees at initial ground contact compared with other manoeuvres. This study examined if the shoe heel curvature design of a badminton shoe would influence shoe-ground kinematics, ground reaction forces, and knee moments during lunge.Eleven elite and fifteen intermediate players performed five left-forward maximum lunge trials with Rounded Heel Shoe (RHS, Flattened Heel Shoe (FHS, and Standard Heel Shoes (SHS. Shoe-ground kinematics, ground reaction forces, and knee moments were measured by using synchronized force platform and motion analysis system. A 2 (Group x 3 (Shoe ANOVA with repeated measures was performed to determine the effects of different shoes and different playing levels, as well as the interaction of two factors on all variables.Shoe effect indicated that players demonstrated lower maximum vertical loading rate in RHS than the other two shoes (P < 0.05. Group effect revealed that elite players exhibited larger footstrike angle, faster approaching speed, lower peak horizontal force and horizontal loading rates but higher vertical loading rates and larger peak knee flexion and extension moments (P < 0.05. Analysis of Interactions of Group x Shoe for maximum and mean vertical loading rates (P < 0.05 indicated that elite players exhibited lower left maximum and mean vertical loading rates in RHS compared to FHS (P < 0.01, while the intermediate group did not show any Shoe effect on vertical loading rates.These findings indicate that shoe heel curvature would play some role in altering ground reaction force impact during badminton lunge. The differences in impact loads and knee moments between elite and intermediate players may be useful in optimizing footwear design and training strategy to minimize the potential risks for impact related injuries in badminton.

Ankle brace attenuates the medial-lateral ground reaction force during basketball rebound jump

Directory of Open Access Journals (Sweden)

Alex Castro

Full Text Available ABSTRACT Introduction: The jump landing is the leading cause for ankle injuries in basketball. It has been shown that the use of ankle brace is effective to prevent these injuries by increasing the mechanical stability of the ankle at the initial contact of the foot with the ground. Objective: To investigate the effects of ankle brace on the ground reaction force (GRF during the simulation of a basketball rebound jump. Method: Eleven young male basketball players randomly carried out a simulated basketball rebound jump under two conditions, with and without ankle brace (lace-up. Dynamic parameters of vertical GRF (take-off and landing vertical peaks, time to take-off and landing vertical peaks, take-off impulse peak, impulse at 50 milliseconds of landing, and jump height and medial-lateral (take-off and landing medial-lateral peaks, and time to reach medial-lateral peaks at take-off and landing were recorded by force platform during rebound jumps in each tested condition. The comparisons between the tested conditions were performed by paired t test (P0.05. Conclusion: The use of ankle brace during basketball rebound jumps attenuates the magnitude of medial-lateral GRF on the landing phase, without changing the vertical GRF. This finding indicates that the use of brace increases the medial-lateral mechanical protection by decreasing the shear force exerted on the athlete’s body without change the application of propulsive forces in the take-off and the impact absorption quality in the landing during the basketball rebound jump.

A Model Ground State of Polyampholytes

International Nuclear Information System (INIS)

Wofling, S.; Kantor, Y.

1998-01-01

The ground state of randomly charged polyampholytes (polymers with positive and negatively charged groups along their backbone) is conjectured to have a structure similar to a necklace, made of weakly charged parts of the chain, compacting into globules, connected by highly charged stretched 'strings' attempted to quantify the qualitative necklace model, by suggesting a zero approximation model, in which the longest neutral segment of the polyampholyte forms a globule, while the remaining part will form a tail. Expanding this approximation, we suggest a specific necklace-type structure for the ground state of randomly charged polyampholyte's, where all the neutral parts of the chain compact into globules: The longest neutral segment compacts into a globule; in the remaining part of the chain, the longest neutral segment (the second longest neutral segment) compacts into a globule, then the third, and so on. A random sequence of charges is equivalent to a random walk, and a neutral segment is equivalent to a loop inside the random walk. We use analytical and Monte Carlo methods to investigate the size distribution of loops in a one-dimensional random walk. We show that the length of the nth longest neutral segment in a sequence of N monomers (or equivalently, the nth longest loop in a random walk of N steps) is proportional to N/n 2 , while the mean number of neutral segments increases as √N. The polyampholytes in the ground state within our model is found to have an average linear size proportional to dN, and an average surface area proportional to N 2/3

Hydrogeology of the 200 Areas low-level burial grounds: An interim report: Volume 2, Appendixes

Energy Technology Data Exchange (ETDEWEB)

Last, G.V.; Bjornstad, B.N.; Bergeron, M.P.; Wallace, D.W.; Newcomer, D.R.; Schramke, J.A.; Chamness, M.A.; Cline, C.S.; Airhart, S.P.; Wilbur, J.S.

1989-01-01

This report presents information derived form the installation of 35 ground-water monitoring wells around six low-level radioactive/hazardous waste burial grounds located in the 200 Areas of the Hanford Site in southeastern Washington State. This information was collected between May 20, 1987 and August 1, 1988. The contents of this report have been divided into two volumes. Volume 1 contains the main text. This Volume contains the appendixes, including data and supporting information that verify content and results found in the main text.

Three-body problem in the ground-state representation

International Nuclear Information System (INIS)

Gonzalez, A.

1993-01-01

The ground-state probability density of a three-body system is used to construct a classical potential U whose minimum coincides exactly with the ground-state energy. The spectrum of excited states may approximately be obtained by imposing quasiclassical quantization conditions over the classical motion in U. We show nontrivial one-dimensional models in which either this quantization condition is exact or considerably improves the usual semiclassical quantization. For three-dimensional problems, the small-oscillation frequencies in states with total angular momentum L = 0 are computed. These frequencies could represent an improvement over the frequencies of triatomic molecules computed with the use of ordinary quasiclassics for the motion of the nuclei in the molecular term. By providing a semiclassical description of the first excited quantum states, the sketched approach rises some interesting questions such as, for example, the relevance (once again) of classical chaos to quantum mechanics

Density-matrix-functional calculations for matter in strong magnetic fields: Ground states of heavy atoms

DEFF Research Database (Denmark)

Johnsen, Kristinn; Yngvason, Jakob

1996-01-01

We report on a numerical study of the density matrix functional introduced by Lieb, Solovej, and Yngvason for the investigation of heavy atoms in high magnetic fields. This functional describes exactly the quantum mechanical ground state of atoms and ions in the limit when the nuclear charge Z...... and the electron number N tend to infinity with N/Z fixed, and the magnetic field B tends to infinity in such a way that B/Z4/3→∞. We have calculated electronic density profiles and ground-state energies for values of the parameters that prevail on neutron star surfaces and compared them with results obtained...... by other methods. For iron at B=1012 G the ground-state energy differs by less than 2% from the Hartree-Fock value. We have also studied the maximal negative ionization of heavy atoms in this model at various field strengths. In contrast to Thomas-Fermi type theories atoms can bind excess negative charge...

The Comparison of Vertical Ground Reaction Force during Forward and Backward Walking among Professional Male Karatekas with Genu Varum and Normal Knees

Directory of Open Access Journals (Sweden)

Heydar Sadeghi

2017-06-01

Conclusion: Based on the results of present study, genu varum can be considered as an effective factor on vertical ground reaction force (as predictor factor of musculoskeletal injuries among the Karate professionals, and backward walking can cause a change in vertical ground reaction force more than forward walking does.

Containment forces in low energy states of plasmoids

International Nuclear Information System (INIS)

Wells, D.R.; Hawkins, L.C.

1987-01-01

The application of Hamilton's principle to the problem of the determination of the structure of low free energy state plasmoids is discussed. It is shown that Clebsch representations of the vector fields and representations involving side conditions on the functional result in the same sets of Euler-Lagrange equations. The relationship of these representations to the problem of containment forces in vortex structures (plasmoids) is considered. It is demonstrated that the lowest free energy state of an incompressible plasma is always Lorentz force and Magnus force free. For a compressible plasma obeying the adiabatic gas laws, the Magnus force is finite. Introduction of conservation of angular momentum as an additional side condition also results in finite containment forces. (author)

Stability of quantum-dot excited-state laser emission under simultaneous ground-state perturbation

Energy Technology Data Exchange (ETDEWEB)

Kaptan, Y., E-mail: yuecel.kaptan@physik.tu-berlin.de; Herzog, B.; Schöps, O.; Kolarczik, M.; Woggon, U.; Owschimikow, N. [Institut für Optik und Atomare Physik, Technische Universität Berlin, Berlin (Germany); Röhm, A.; Lingnau, B.; Lüdge, K. [Institut für Theoretische Physik, Technische Universität Berlin, Berlin (Germany); Schmeckebier, H.; Arsenijević, D.; Bimberg, D. [Institut für Festkörperphysik, Technische Universität Berlin, Berlin (Germany); Mikhelashvili, V.; Eisenstein, G. [Technion Institute of Technology, Faculty of Electrical Engineering, Haifa (Israel)

2014-11-10

The impact of ground state amplification on the laser emission of In(Ga)As quantum dot excited state lasers is studied in time-resolved experiments. We find that a depopulation of the quantum dot ground state is followed by a drop in excited state lasing intensity. The magnitude of the drop is strongly dependent on the wavelength of the depletion pulse and the applied injection current. Numerical simulations based on laser rate equations reproduce the experimental results and explain the wavelength dependence by the different dynamics in lasing and non-lasing sub-ensembles within the inhomogeneously broadened quantum dots. At high injection levels, the observed response even upon perturbation of the lasing sub-ensemble is small and followed by a fast recovery, thus supporting the capacity of fast modulation in dual-state devices.

Structural instability and ground state of the U{sub 2}Mo compound

Energy Technology Data Exchange (ETDEWEB)

Losada, E.L., E-mail: losada@cab.cnea.gov.ar [SIM" 3, Centro Atómico Bariloche, Comisión Nacional de Energía Atómica (Argentina); Garcés, J.E. [Gerencia de Investigación y Aplicaciones Nucleares, Comisión Nacional de Energía Atómica (Argentina)

2015-11-15

This work reports on the structural instability at T = 0 °K of the U{sub 2}Mo compound in the C11{sub b} structure under the distortion related to the C{sub 66} elastic constant. The electronic properties of U{sub 2}Mo such as density of states (DOS), bands and Fermi surface (FS) are studied to understand the source of the instability. The C11{sub b} structure can be interpreted as formed by parallel linear chains along the z-directions each one composed of successive U–Mo–U blocks. Hybridization due to electronic interactions inside the U–Mo–U blocks is slightly modified under the D{sub 6} distortion. The change in distance between chains modifies the U–U interaction and produces a split of f-states. The distorted structure is stabilized by a decrease in energy of the hybridized states, mainly between d-Mo and f-U states, together with the f-band split. Consequently, an induced Peierls distortion is produced in U{sub 2}Mo due to the D{sub 6} distortion. It is important to note that the results of this work indicate that the structure of the ground state of the U{sub 2}Mo compound is not the assumed C11{sub b} structure. It is suggested for the ground state a structure with hexagonal symmetry (P6 #168), ∼0.1 mRy below the energy of the recently proposed Pmmn structure. - Highlights: • Structural instability of the C11b compound due to the D6 deformation. • Induced Peierls distortion due to the D6 deformation. • Distorted structure is stabilized by hybridization and split of f-Uranium state. • P6 (#168) suggested ground state for the U{sub 2}Mo compound.

Does shoe heel design influence ground reaction forces and knee moments during maximum lunges in elite and intermediate badminton players?

Science.gov (United States)

Lam, Wing-Kai; Ryue, Jaejin; Lee, Ki-Kwang; Park, Sang-Kyoon; Cheung, Jason Tak-Man; Ryu, Jiseon

2017-01-01

Lunge is one frequently executed movement in badminton and involves a unique sagittal footstrike angle of more than 40 degrees at initial ground contact compared with other manoeuvres. This study examined if the shoe heel curvature design of a badminton shoe would influence shoe-ground kinematics, ground reaction forces, and knee moments during lunge. Eleven elite and fifteen intermediate players performed five left-forward maximum lunge trials with Rounded Heel Shoe (RHS), Flattened Heel Shoe (FHS), and Standard Heel Shoes (SHS). Shoe-ground kinematics, ground reaction forces, and knee moments were measured by using synchronized force platform and motion analysis system. A 2 (Group) x 3 (Shoe) ANOVA with repeated measures was performed to determine the effects of different shoes and different playing levels, as well as the interaction of two factors on all variables. Shoe effect indicated that players demonstrated lower maximum vertical loading rate in RHS than the other two shoes (P badminton lunge. The differences in impact loads and knee moments between elite and intermediate players may be useful in optimizing footwear design and training strategy to minimize the potential risks for impact related injuries in badminton.

On calculations of the ground state energy in quantum mechanics

International Nuclear Information System (INIS)

Efimov, G.V.

1991-02-01

In nonrelativistic quantum mechanics the Wick-ordering method called the oscillator representation suggested to calculate the ground-state energy for a wide class of potentials allowing the existence of a bound state. The following examples are considered: the orbital excitations of the ground-state in the Coulomb plus linear potential, the Schroedinger equation with a ''relativistic'' kinetic energy √p 2 +m 2 , the Coulomb three-body problem. (author). 22 refs, 2 tabs

The Comparison of Vertical Ground Reaction Force during Forward and Backward Walking among Professional Male Karatekas with Genu Varum and Normal Knees

OpenAIRE

Heydar Sadeghi; Siavash Shirvanipour; Raghad Mimar

2017-01-01

Objective: The purpose of this study was to compare vertical ground reaction force during forward and backward walking among the male professional Karatekas with genu varum and normal knee. Methods: 20 professional male Karates (in genu varum and normal groups) participated in this semi-experimental study. The vertical ground reaction force was measured using force plate system during forward and backward walking utilizing 250 Hz frequency. Mixed ANOVA test was run to analyze the obtained ...

Ground-state structures of Hafnium clusters

Energy Technology Data Exchange (ETDEWEB)

Ng, Wei Chun; Yoon, Tiem Leong [School of Physics, Universiti Sains Malaysia, 11800 USM, Penang (Malaysia); Lim, Thong Leng [Faculty of Engineering and Technoloty, Multimedia University, Melaca Campus, 75450 Melaka (Malaysia)

2015-04-24

Hafnium (Hf) is a very large tetra-valence d-block element which is able to form relatively long covalent bond. Researchers are interested to search for substitution to silicon in the semi-conductor industry. We attempt to obtain the ground-state structures of small Hf clusters at both empirical and density-functional theory (DFT) levels. For calculations at the empirical level, charge-optimized many-body functional potential (COMB) is used. The lowest-energy structures are obtained via a novel global-minimum search algorithm known as parallel tempering Monte-Carlo Basin-Hopping and Genetic Algorithm (PTMBHGA). The virtue of using COMB potential for Hf cluster calculation lies in the fact that by including the charge optimization at the valence shells, we can encourage the formation of proper bond hybridization, and thus getting the correct bond order. The obtained structures are further optimized using DFT to ensure a close proximity to the ground-state.

Probing quantum frustrated systems via factorization of the ground state.

Science.gov (United States)

Giampaolo, Salvatore M; Adesso, Gerardo; Illuminati, Fabrizio

2010-05-21

The existence of definite orders in frustrated quantum systems is related rigorously to the occurrence of fully factorized ground states below a threshold value of the frustration. Ground-state separability thus provides a natural measure of frustration: strongly frustrated systems are those that cannot accommodate for classical-like solutions. The exact form of the factorized ground states and the critical frustration are determined for various classes of nonexactly solvable spin models with different spatial ranges of the interactions. For weak frustration, the existence of disentangling transitions determines the range of applicability of mean-field descriptions in biological and physical problems such as stochastic gene expression and the stability of long-period modulated structures.

In-Shoe Plantar Pressures and Ground Reaction Forces during Overweight Adults' Overground Walking

Science.gov (United States)

de Castro, Marcelo P.; Abreu, Sofia C.; Sousa, Helena; Machado, Leandro; Santos, Rubim; Vilas-Boas, João Paulo

2014-01-01

Purpose: Because walking is highly recommended for prevention and treatment of obesity and some of its biomechanical aspects are not clearly understood for overweight people, we compared the absolute and normalized ground reaction forces (GRF), plantar pressures, and temporal parameters of normal-weight and overweight participants during…

Ground-state fidelity in the BCS-BEC crossover

International Nuclear Information System (INIS)

Khan, Ayan; Pieri, Pierbiagio

2009-01-01

The ground-state fidelity has been introduced recently as a tool to investigate quantum phase transitions. Here, we apply this concept in the context of a crossover problem. Specifically, we calculate the fidelity susceptibility for the BCS ground-state wave function, when the intensity of the fermionic attraction is varied from weak to strong in an interacting Fermi system, through the BCS-Bose-Einstein Condensation crossover. Results are presented for contact and finite-range attractive potentials and for both continuum and lattice models. We conclude that the fidelity susceptibility can be useful also in the context of crossover problems.

Antiferrodistortive phase transitions and ground state of PZT ceramics

International Nuclear Information System (INIS)

Pandey, Dhananjai

2013-01-01

The ground state of the technologically important Pb(Zr x Ti (1-x) )O 3 , commonly known as PZT, ceramics is currently under intense debate. The phase diagram of this material shows a morphotropic phase boundary (MPB) for x∼0.52 at 300K, across which a composition induced structural phase transition occurs leading to maximization of the piezoelectric properties. In search for the true ground state of the PZT in the MPB region, Beatrix Noheda and coworkers first discovered a phase transition from tetragonal (space group P4mm) to an M A type monoclinic phase (space group Cm) at low temperatures for x=0.52. Soon afterwards, we discovered yet another low temperature phase transition for the same composition in which the M A type (Cm) monoclinic phase transforms to another monoclinic phase with Cc space group. We have shown that the Cm to Cc phase transition is an antiferrodistortive (AFD) transition involving tilting of oxygen octahedra leading to unit cell doubling and causing appearance of superlattice reflections which are observable in the electron and neutron diffraction patterns only and not in the XRD patterns, as a result of which Noheda and coworkers missed the Cc phase in their synchrotron XRD studies at low temperatures. Our findings were confirmed by leading groups using neutron, TEM, Raman and high pressure diffraction studies. The first principles calculations also confirmed that the true ground state of PZT in the MPB region has Cc space group. However, in the last couple of years, the Cc space group of the ground state has become controversial with an alternative proposal of R3c as the space group of the ground state phase which is proposed to coexist with the metastable Cm phase. In order to resolve this controversy, we recently revisited the issue using pure PZT and 6% Sr 2+ substituted PZT, the latter samples show larger tilt angle on account of the reduction in the average cationic radius at the Pb 2+ site. Using high wavelength neutrons and high

Ground state correlations and structure of odd spherical nuclei

International Nuclear Information System (INIS)

Mishev, S.; Voronov, V. V.

2006-01-01

It is well known that the Pauli principle plays a substantial role at low energies because the phonon operators are not ideal boson operators. Calculating the exact commutators between the quasiparticle and phonon operators one can take into account the Pauli principle corrections. Besides the ground state correlations due to the quasiparticle interaction in the ground state influence the single particle fragmentation as well. In this paper, we generalize the basic QPM equations to account for both mentioned effects. As an illustration of our approach, calculations on the structure of the low-lying states in "1"3"1Ba have been performed.

Ground-state splitting of ultrashallow thermal donors with negative central-cell corrections in silicon

Science.gov (United States)

Hara, Akito; Awano, Teruyoshi

2017-06-01

Ultrashallow thermal donors (USTDs), which consist of light element impurities such as carbon, hydrogen, and oxygen, have been found in Czochralski silicon (CZ Si) crystals. To the best of our knowledge, these are the shallowest hydrogen-like donors with negative central-cell corrections in Si. We observed the ground-state splitting of USTDs by far-infrared optical absorption at different temperatures. The upper ground-state levels are approximately 4 meV higher than the ground-state levels. This energy level splitting is also consistent with that obtained by thermal excitation from the ground state to the upper ground state. This is direct evidence that the wave function of the USTD ground state is made up of a linear combination of conduction band minimums.

System of gait analysis based on ground reaction force assessment

Directory of Open Access Journals (Sweden)

František Vaverka

2015-12-01

Full Text Available Background: Biomechanical analysis of gait employs various methods used in kinematic and kinetic analysis, EMG, and others. One of the most frequently used methods is kinetic analysis based on the assessment of the ground reaction forces (GRF recorded on two force plates. Objective: The aim of the study was to present a method of gait analysis based on the assessment of the GRF recorded during the stance phase of two steps. Methods: The GRF recorded with a force plate on one leg during stance phase has three components acting in directions: Fx - mediolateral, Fy - anteroposterior, and Fz - vertical. A custom-written MATLAB script was used for gait analysis in this study. This software displays instantaneous force data for both legs as Fx(t, Fy(t and Fz(t curves, automatically determines the extremes of functions and sets the visual markers defining the individual points of interest. Positions of these markers can be easily adjusted by the rater, which may be necessary if the GRF has an atypical pattern. The analysis is fully automated and analyzing one trial takes only 1-2 minutes. Results: The method allows quantification of temporal variables of the extremes of the Fx(t, Fy(t, Fz(t functions, durations of the braking and propulsive phase, duration of the double support phase, the magnitudes of reaction forces in extremes of measured functions, impulses of force, and indices of symmetry. The analysis results in a standardized set of 78 variables (temporal, force, indices of symmetry which can serve as a basis for further research and diagnostics. Conclusions: The resulting set of variable offers a wide choice for selecting a specific group of variables with consideration to a particular research topic. The advantage of this method is the standardization of the GRF analysis, low time requirements allowing rapid analysis of a large number of trials in a short time, and comparability of the variables obtained during different research measurements.

Coexisting Kondo singlet state with antiferromagnetic long-range order: A possible ground state for Kondo insulators

International Nuclear Information System (INIS)

Zhang Guangming; Yu Lu

2000-04-01

The ground-state phase diagram of a half-filled anisotropic Kondo lattice model is calculated within a mean-field theory. For small transverse exchange coupling J perpendicular perpendicular c1 , the ground state shows an antiferromagnetic long-range order with finite staggered magnetizations of both localized spins and conduction electrons. When J perpendicular > J perpendicular c2 , the long-range order is destroyed and the system is in a disordered Kondo singlet state with a hybridization gap. Both ground states can describe the low-temperature phases of Kondo insulating compounds. Between these two distinct phases, there may be a coexistent regime as a result of the balance between local Kondo screening and magnetic interactions. (author)

Radon concentrations in ground and drinking water in the state of Chihuahua, Mexico

Energy Technology Data Exchange (ETDEWEB)

Villalba, L. [Centro de Investigacion en Materiales Avanzados, S.C., Miguel de Cervantes 120, Complejo Industrial Chihuahua, CP 31109 Chihuahua, Chih. (Mexico); Colmenero Sujo, L. [Centro de Investigacion en Materiales Avanzados, S.C., Miguel de Cervantes 120, Complejo Industrial Chihuahua, CP 31109 Chihuahua, Chih. (Mexico); Instituto Tecnologico de Chihuahua II, Ave. de las Industrias 11101, Chihuahua, Chih. (Mexico); Montero Cabrera, M.E. [Centro de Investigacion en Materiales Avanzados, S.C., Miguel de Cervantes 120, Complejo Industrial Chihuahua, CP 31109 Chihuahua, Chih. (Mexico)]. E-mail: elena.montero@cimav.edu.mx; Cano Jimenez, A. [Centro de Investigacion en Materiales Avanzados, S.C., Miguel de Cervantes 120, Complejo Industrial Chihuahua, CP 31109 Chihuahua, Chih. (Mexico); Renteria Villalobos, M. [Centro de Investigacion en Materiales Avanzados, S.C., Miguel de Cervantes 120, Complejo Industrial Chihuahua, CP 31109 Chihuahua, Chih. (Mexico); Delgado Mendoza, C.J. [Facultad de Ciencias Quimicas, Universidad Autonoma de Chihuahua, Ciudad Universitaria S/N, Chihuahua, Chih. (Mexico); Jurado Tenorio, L.A. [Facultad de Ciencias Quimicas, Universidad Autonoma de Chihuahua, Ciudad Universitaria S/N, Chihuahua, Chih. (Mexico); Davila Rangel, I. [Centro Regional de Estudios Nucleares, Universidad Autonoma de Zacatecas, Cipres 20, Zacatecas, Zac. (Mexico); Herrera Peraza, E.F. [Centro de Investigacion en Materiales Avanzados, S.C., Miguel de Cervantes 120, Complejo Industrial Chihuahua, CP 31109 Chihuahua, Chih. (Mexico)

2005-07-01

This paper reports {sup 222}Rn concentrations in ground and drinking water of nine cities of Chihuahua State, Mexico. Fifty percent of the 114 sampled wells exhibited {sup 222}Rn concentrations exceeding 11 Bq/L, the maximum contaminant level (MCL) recommended by the USEPA. Furthermore, around 48% (123 samples) of the tap-water samples taken from 255 dwellings showed radon concentrations over the MCL. There is an apparent correlation between total dissolved solids and radon concentration in ground-water. The high levels of {sup 222}Rn found may be entirely attributed to the nature of aquifer rocks.

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

International Nuclear Information System (INIS)

1992-04-01

This Removal Action System Design has been prepared as a Phase I Volume for the implementation of the Phase II removal action at Wright-Patterson Air Force Base (WPAFB) near Dayton, Ohio. The objective of the removal action is to prevent, to the extent practicable, the migration of ground water contaminated with chlorinated volatile organic compounds (VOCS) across the southwest boundary of Area C. The Phase 1, Volume 9 Removal Action System Design compiles the design documents prepared for the Phase II Removal Action. These documents, which are presented in Appendices to Volume 9, include: Process Design, which presents the 30 percent design for the ground water treatment system (GWTS); Design Packages 1 and 2 for Earthwork and Road Construction, and the Discharge Pipeline, respectively; no drawings are included in the appendix; Design Package 3 for installation of the Ground Water Extraction Well(s); Design Package 4 for installation of the Monitoring Well Instrumentation; and Design Package 5 for installation of the Ground Water Treatment System; this Design Package is incorporated by reference because of its size

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

Rearrangements in ground and excited states

CERN Document Server

de Mayo, Paul

1980-01-01

Rearrangements in Ground and Excited States, Volume 3 presents essays on the chemical generation of excited states; the cis-trans isomerization of olefins; and the photochemical rearrangements in trienes. The book also includes essays on the zimmerman rearrangements; the photochemical rearrangements of enones; the photochemical rearrangements of conjugated cyclic dienones; and the rearrangements of the benzene ring. Essays on the photo rearrangements via biradicals of simple carbonyl compounds; the photochemical rearrangements involving three-membered rings or five-membered ring heterocycles;

Step-to-step spatiotemporal variables and ground reaction forces of intra-individual fastest sprinting in a single session.

Science.gov (United States)

Nagahara, Ryu; Mizutani, Mirai; Matsuo, Akifumi; Kanehisa, Hiroaki; Fukunaga, Tetsuo

2018-06-01

We aimed to investigate the step-to-step spatiotemporal variables and ground reaction forces during the acceleration phase for characterising intra-individual fastest sprinting within a single session. Step-to-step spatiotemporal variables and ground reaction forces produced by 15 male athletes were measured over a 50-m distance during repeated (three to five) 60-m sprints using a long force platform system. Differences in measured variables between the fastest and slowest trials were examined at each step until the 22nd step using a magnitude-based inferences approach. There were possibly-most likely higher running speed and step frequency (2nd to 22nd steps) and shorter support time (all steps) in the fastest trial than in the slowest trial. Moreover, for the fastest trial there were likely-very likely greater mean propulsive force during the initial four steps and possibly-very likely larger mean net anterior-posterior force until the 17th step. The current results demonstrate that better sprinting performance within a single session is probably achieved by 1) a high step frequency (except the initial step) with short support time at all steps, 2) exerting a greater mean propulsive force during initial acceleration, and 3) producing a greater mean net anterior-posterior force during initial and middle acceleration.

Regional analysis of ground and above-ground climate

Energy Technology Data Exchange (ETDEWEB)

1981-12-01

The regional suitability of underground construction as a climate control technique is discussed with reference to (1) a bioclimatic analysis of long-term weather data for 29 locations in the United States to determine appropriate above ground climate control techniques, (2) a data base of synthesized ground temperatures for the coterminous United States, and (3) monthly dew point ground temperature comparisons for identifying the relative likelihood of condensation from one region to another. It is concluded that the suitability of earth tempering as a practice and of specific earth-sheltered design stereotypes varies geographically; while the subsurface almost always provides a thermal advantage on its own terms when compared to above ground climatic data, it can, nonetheless, compromise the effectiveness of other, regionally more important climate control techniques. Also contained in the report are reviews of above and below ground climate mapping schemes related to human comfort and architectural design, and detailed description of a theoretical model of ground temperature, heat flow, and heat storage in the ground. Strategies of passive climate control are presented in a discussion of the building bioclimatic analysis procedure which has been applied in a computer analysis of 30 years of weather data for each of 29 locations in the United States.

Stochastic ground-water flow analysis FY-81 status report. Assessment of effectiveness of geologic isolation systems

International Nuclear Information System (INIS)

Kincaid, C.T.; Vail, L.W.; Devary, J.L.

1983-07-01

Research was conducted at Pacific Northwest Laboratory to develop a research computational package for the stochastic analysis of ground-water flow. Both unsteady and steady-state analysis were examined, and a steady-state research code was developed for the study of stochastic processes. This report describes the theoretical development of both unsteady and steady analyses, and presents the preliminary studies undertaken to verify and exercise the encoded algorithm. The stochastic analysis of ground-water flow is a promising new method which can supply more comprehensive analyses of the ground-water environment. The work reported herein provided experience in the methodology while producing a research-oriented stochastic analysis capability. Single-layer aquifers of horizontal extent were selected for this effort. Kriging has been employed to describe the uncertainty in field data. The resulting stochastic parameters enter the problem physics through boundary conditions and Darcy's equation. The mean and variance of the piezometric head are estimated by the stochastic analysis

Timing differences in the generation of ground reaction forces between the initial and secondary landing phases of the drop vertical jump.

Science.gov (United States)

Bates, Nathaniel A; Ford, Kevin R; Myer, Gregory D; Hewett, Timothy E

2013-08-01

Rapid impulse loads imparted on the lower extremity from ground contact when landing from a jump may contribute to ACL injury prevalence in female athletes. The drop jump and drop landing tasks enacted in the first and second landings of drop vertical jumps, respectively, have been shown to elicit separate neuromechanical responses. We examined the first and second landings of a drop vertical jump for differences in landing phase duration, time to peak force, and rate of force development. 239 adolescent female basketball players completed drop vertical jumps from an initial height of 31cm. In-ground force platforms and a three dimensional motion capture system recorded force and positional data for each trial. Between the first and second landing, rate of force development experienced no change (P>0.62), landing phase duration decreased (P=0.01), and time to peak ground reaction force increased (P0.12). The current results have important implications for the future assessment of ACL injury risk behaviors. Rate of force development remained unchanged between first and second landings from equivalent fall height, while time to peak reaction force increased during the second landing. Neither factor was dependent on the total time duration of landing phase, which decreased during the second landing. Shorter time to peak force may increase ligament strain and better represent the abrupt joint loading that is associated with ACL injury risk. © 2013.

Ground-state densities from the Rayleigh-Ritz variation principle and from density-functional theory.

Science.gov (United States)

Kvaal, Simen; Helgaker, Trygve

2015-11-14

The relationship between the densities of ground-state wave functions (i.e., the minimizers of the Rayleigh-Ritz variation principle) and the ground-state densities in density-functional theory (i.e., the minimizers of the Hohenberg-Kohn variation principle) is studied within the framework of convex conjugation, in a generic setting covering molecular systems, solid-state systems, and more. Having introduced admissible density functionals as functionals that produce the exact ground-state energy for a given external potential by minimizing over densities in the Hohenberg-Kohn variation principle, necessary and sufficient conditions on such functionals are established to ensure that the Rayleigh-Ritz ground-state densities and the Hohenberg-Kohn ground-state densities are identical. We apply the results to molecular systems in the Born-Oppenheimer approximation. For any given potential v ∈ L(3/2)(ℝ(3)) + L(∞)(ℝ(3)), we establish a one-to-one correspondence between the mixed ground-state densities of the Rayleigh-Ritz variation principle and the mixed ground-state densities of the Hohenberg-Kohn variation principle when the Lieb density-matrix constrained-search universal density functional is taken as the admissible functional. A similar one-to-one correspondence is established between the pure ground-state densities of the Rayleigh-Ritz variation principle and the pure ground-state densities obtained using the Hohenberg-Kohn variation principle with the Levy-Lieb pure-state constrained-search functional. In other words, all physical ground-state densities (pure or mixed) are recovered with these functionals and no false densities (i.e., minimizing densities that are not physical) exist. The importance of topology (i.e., choice of Banach space of densities and potentials) is emphasized and illustrated. The relevance of these results for current-density-functional theory is examined.

Ground state correlations and structure of odd spherical nuclei

International Nuclear Information System (INIS)

Mishev, S.; Voronov, V.V.

2008-01-01

It is well known that the Pauli principle plays a substantial role at low energies because the phonon operators are not ideal boson operators. Calculating the exact commutators between the quasiparticle and phonon operators one can take into account the Pauli principle corrections. Besides, the ground state correlations due to the quasiparticle interaction in the ground state influence the single-particle fragmentation as well. In this paper, we generalize the basic equations of the quasiparticle-phonon nuclear model to account for both effects mentioned. As an illustration of our approach, calculations on the structure of the low-lying states in 133 Ba have been performed

Adaptive locomotor training on an end-effector gait robot: evaluation of the ground reaction forces in different training conditions.

Science.gov (United States)

Tomelleri, Christopher; Waldner, Andreas; Werner, Cordula; Hesse, Stefan

2011-01-01

The main goal of robotic gait rehabilitation is the restoration of independent gait. To achieve this goal different and specific patterns have to be practiced intensively in order to stimulate the learning process of the central nervous system. The gait robot G-EO Systems was designed to allow the repetitive practice of floor walking, stair climbing and stair descending. A novel control strategy allows training in adaptive mode. The force interactions between the foot and the ground were analyzed on 8 healthy volunteers in three different conditions: real floor walking on a treadmill, floor walking on the gait robot in passive mode, floor walking on the gait robot in adaptive mode. The ground reaction forces were measured by a Computer Dyno Graphy (CDG) analysis system. The results show different intensities of the ground reaction force across all of the three conditions. The intensities of force interactions during the adaptive training mode are comparable to the real walking on the treadmill. Slight deviations still occur in regard to the timing pattern of the forces. The adaptive control strategy comes closer to the physiological swing phase than the passive mode and seems to be a promising option for the treatment of gait disorders. Clinical trials will validate the efficacy of this new option in locomotor therapy on the patients. © 2011 IEEE

Ground state of the parallel double quantum dot system.

Science.gov (United States)

Zitko, Rok; Mravlje, Jernej; Haule, Kristjan

2012-02-10

We resolve the controversy regarding the ground state of the parallel double quantum dot system near half filling. The numerical renormalization group predicts an underscreened Kondo state with residual spin-1/2 magnetic moment, ln2 residual impurity entropy, and unitary conductance, while the Bethe ansatz solution predicts a fully screened impurity, regular Fermi-liquid ground state, and zero conductance. We calculate the impurity entropy of the system as a function of the temperature using the hybridization-expansion continuous-time quantum Monte Carlo technique, which is a numerically exact stochastic method, and find excellent agreement with the numerical renormalization group results. We show that the origin of the unconventional behavior in this model is the odd-symmetry "dark state" on the dots.

Ground and excited state properties of high performance anthocyanidin dyes-sensitized solar cells in the basic solutions

Energy Technology Data Exchange (ETDEWEB)

Prima, Eka Cahya [Advanced Functional Material Laboratory, Engineering Physics, Institut Teknologi Bandung (Indonesia); Computational Material Design and Quantum Engineering Laboratory, Engineering Physics, Institut Teknologi Bandung (Indonesia); International Program on Science Education, Universitas Pendidikan Indonesia (Indonesia); Yuliarto, Brian; Suyatman, E-mail: yatman@tf.itb.ac.id [Advanced Functional Material Laboratory, Engineering Physics, Institut Teknologi Bandung (Indonesia); Dipojono, Hermawan Kresno [Computational Material Design and Quantum Engineering Laboratory, Engineering Physics, Institut Teknologi Bandung (Indonesia)

2015-09-30

The aglycones of anthocyanidin dyes were previously reported to form carbinol pseudobase, cis-chalcone, and trans-chalcone due to the basic levels. The further investigations of ground and excited state properties of the dyes were characterized using density functional theory with PCM(UFF)/B3LYP/6-31+G(d,p) level in the basic solutions. However, to the best of our knowledge, the theoretical investigation of their potential photosensitizers has never been reported before. In this paper, the theoretical photovoltaic properties sensitized by dyes have been successfully investigated including the electron injections, the ground and excited state oxidation potentials, the estimated open circuit voltages, and the light harvesting efficiencies. The results prove that the electronic properties represented by dyes’ LUMO-HOMO levels will affect to the photovoltaic performances. Cis-chalcone dye is the best anthocyanidin aglycone dye with the electron injection spontaneity of −1.208 eV, the theoretical open circuit voltage of 1.781 V, and light harvesting efficiency of 56.55% due to the best HOMO-LUMO levels. Moreover, the ethanol solvent slightly contributes to the better cell performance than the water solvent dye because of the better oxidation potential stabilization in the ground state as well as in the excited state. These results are in good agreement with the known experimental report that the aglycones of anthocyanidin dyes in basic solvent are the high potential photosensitizers for dye-sensitized solar cell.

RPA ground state correlations in nuclei

International Nuclear Information System (INIS)

Lenske, H.

1990-01-01

Overcounting in the RPA theory of ground state correlations is shown to be avoided if exact rather than quasiboson commutators are used. Single particle occupation probabilities are formulated in a compact way by the RPA Green function. Calculations with large configuration spaces and realistic interactions are performed with 1p1h RPA and second RPA (SRPA) including 2p2h mixing in excited states. In 41 Ca valence hole states are found to be quenched by about 10% in RPA and up to 18% in SRPA. Contributions from low and high lying excitations and their relation to long and short range correlations in finite nuclei are investigated. (orig.)

A COMPARISON OF GROUND REACTION FORCES DETERMINED BY PORTABLE FORCE-PLATE AND PRESSURE-INSOLE SYSTEMS IN ALPINE SKIING

Directory of Open Access Journals (Sweden)

Kosuke Nakazato

2011-12-01

Full Text Available For the determination of ground reaction forces in alpine skiing, pressure insole (PI systems and portable force plate (FP systems are well known and widely used in previous studies. The purposes of this study were 1 to provide reference data for the vertical component of the ground reaction forces (vGRF during alpine skiing measured by the PI and FP systems, and 2 to analyze whether the differences in the vGRF measured by the PI and the FP depend on a skier's level, skiing mode and pitch. Ten expert and ten intermediate level skiers performed 10 double turns with the skiing technique "Carving in Short Radii" as High Dynamic Skiing mode and "Parallel Ski Steering in Long Radii" as Low Dynamic Skiing mode on both the steep (23 ° and the flat (15 ° slope twice. All subjects skied with both the PI and the FP system simultaneously. During the outside phase, the mean vGRF and the maximum vGRF determined by the FP are greater than the PI (p < 0.01. Additionally during the inside phase, the mean vGRF determined by the FP were greater than the PI (p < 0.01. During the edge changing phases, the mean vGRF determined by the FP were greater than the PI (p < 0.01. However, the minimum vGRF during the edge changing phases determined by the FP were smaller than the PI (p < 0.01 in the High-Steep skiing modes of Experts and Intermediates (p < 0.001. We have found that generally, the PI system underestimates the total vGRF compared to the FP system. However, this difference depends not only the phase in the turn (inside, outside, edge changing, but also is affected by the skier's level, the skiing mode performed and pitch.

Structural Distortion Stabilizing the Antiferromagnetic and Semiconducting Ground State of BaMn2As2

Directory of Open Access Journals (Sweden)

Ekkehard Krüger

2016-09-01

Full Text Available We report evidence that the experimentally found antiferromagnetic structure as well as the semiconducting ground state of BaMn 2 As 2 are caused by optimally-localized Wannier states of special symmetry existing at the Fermi level of BaMn 2 As 2 . In addition, we find that a (small tetragonal distortion of the crystal is required to stabilize the antiferromagnetic semiconducting state. To our knowledge, this distortion has not yet been established experimentally.

Do ground reaction forces during unilateral and bilateral movements exhibit compensation strategies following ACL reconstruction?

NARCIS (Netherlands)

Baumgart, Christian; Schubert, Markus; Hoppe, Matthias W.; Gokeler, Alli; Freiwald, Juergen

The aims of the study were (1) to evaluate the leg asymmetry assessed with ground reaction forces (GRFs) during unilateral and bilateral movements of different knee loads in anterior cruciate ligament (ACL) reconstructed patients and (2) to investigate differences in leg asymmetry depending on the

Nuclear level densities with pairing and self-consistent ground-state shell effects

CERN Document Server

Arnould, M

1981-01-01

Nuclear level density calculations are performed using a model of fermions interacting via the pairing force, and a realistic single particle potential. The pairing interaction is treated within the BCS approximation with different pairing strength values. The single particle potentials are derived in the framework of an energy-density formalism which describes self-consistently the ground states of spherical nuclei. These calculations are extended to statistically deformed nuclei, whose estimated level densities include rotational band contributions. The theoretical results are compared with various experimental data. In addition, the level densities for several nuclei far from stability are compared with the predictions of a back-shifted Fermi gas model. Such a comparison emphasizes the possible danger of extrapolating to unknown nuclei classical level density formulae whose parameter values are tailored for known nuclei. (41 refs).

Revitalizing Rural Washington: Report and Recommendations of the Governor's Task Force on Rural Affairs.

Science.gov (United States)

Governor's Task Force on Rural Affairs, Olympia, WA.

Recognizing that urban and rural problems are interconnected, the Governor's Advisory Council on Urban Affairs (State of Washington), made a recommendation that led to formation (in 1970) of the Task Force on Rural Affairs. The report of that task force identifies the continuing technological revolution in agriculture as an important cause of (1)…

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

International Nuclear Information System (INIS)

Liu, Tao; Inoue, Yoshio; Shibata, Kyoko

2010-01-01

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

Cluster decay of Ba isotopes from ground state and as an excited ...

Indian Academy of Sciences (India)

otherwise, inclusion of excitation energy decreases the T1/2 values. ... penetrates the nuclear barrier and reaches scission configuration after running .... between the ground-state energy levels of the parent nuclei and the ground-state energy.

Magnetic properties of singlet ground state systems

International Nuclear Information System (INIS)

Diederix, K.M.

1979-01-01

Experiments are described determining the properties of a magnetic system consisting of a singlet ground state. Cu(NO 3 ) 2 .2 1/2H 2 O has been studied which is a system of S = 1/2 alternating antiferromagnetic Heisenberg chains. The static properties, spin lattice relaxation time and field-induced antiferromagnetically ordered state measurements are presented. Susceptibility and magnetic cooling measurements of other compounds are summarised. (Auth.)

Gapless Spin-Liquid Ground State in the S =1 /2 Kagome Antiferromagnet

Science.gov (United States)

Liao, H. J.; Xie, Z. Y.; Chen, J.; Liu, Z. Y.; Xie, H. D.; Huang, R. Z.; Normand, B.; Xiang, T.

2017-03-01

The defining problem in frustrated quantum magnetism, the ground state of the nearest-neighbor S =1 /2 antiferromagnetic Heisenberg model on the kagome lattice, has defied all theoretical and numerical methods employed to date. We apply the formalism of tensor-network states, specifically the method of projected entangled simplex states, which combines infinite system size with a correct accounting for multipartite entanglement. By studying the ground-state energy, the finite magnetic order appearing at finite tensor bond dimensions, and the effects of a next-nearest-neighbor coupling, we demonstrate that the ground state is a gapless spin liquid. We discuss the comparison with other numerical studies and the physical interpretation of this result.

Long range order in the ground state of two-dimensional antiferromagnets

International Nuclear Information System (INIS)

Neves, E.J.; Perez, J.F.

1985-01-01

The existence of long range order is shown in the ground state of the two-dimensional isotropic Heisenberg antiferromagnet for S >= 3/2. The method yields also long range order for the ground state of a larger class of anisotropic quantum antiferromagnetic spin systems with or without transverse magnetic fields. (Author) [pt

Learning Approach on the Ground State Energy Calculation of Helium Atom

International Nuclear Information System (INIS)

Shah, Syed Naseem Hussain

2010-01-01

This research investigated the role of learning approach on the ground state energy calculation of Helium atom in improving the concepts of science teachers at university level. As the exact solution of several particles is not possible here we used approximation methods. Using this method one can understand easily the calculation of ground state energy of any given function. Variation Method is one of the most useful approximation methods in estimating the energy eigen values of the ground state and the first few excited states of a system, which we only have a qualitative idea about the wave function.The objective of this approach is to introduce and involve university teacher in new research, to improve their class room practices and to enable teachers to foster critical thinking in students.

Thermodynamic Ground States of Complex Oxide Heterointerfaces

DEFF Research Database (Denmark)

Gunkel, F.; Hoffmann-Eifert, S.; Heinen, R. A.

2017-01-01

The formation mechanism of 2-dimensional electron gases (2DEGs) at heterointerfaces between nominally insulating oxides is addressed with a thermodynamical approach. We provide a comprehensive analysis of the thermodynamic ground states of various 2DEG systems directly probed in high temperature...

On the ground state for fractional quantum hall effect

International Nuclear Information System (INIS)

Jellal, A.

1998-09-01

In the present letter, we investigate the ground state wave function for an explicit model of electrons in an external magnetic field with specific inter-particle interactions. The excitation states of this model are also given. (author)

Timing differences in the generation of ground reaction forces between the initial and secondary landing phases of the drop vertical jump ☆

Science.gov (United States)

Bates, Nathaniel A.; Ford, Kevin R.; Myer, Gregory D.; Hewett, Timothy E.

2014-01-01

Background Rapid impulse loads imparted on the lower extremity from ground contact when landing from a jump may contribute to ACL injury prevalence in female athletes. The drop jump and drop landing tasks enacted in the first and second landings of drop vertical jumps, respectively, have been shown to elicit separate neuromechanical responses. We examined the first and second landings of a drop vertical jump for differences in landing phase duration, time to peak force, and rate of force development. Methods 239 adolescent female basketball players completed drop vertical jumps from an initial height of 31 cm. In-ground force platforms and a three dimensional motion capture system recorded force and positional data for each trial. Findings Between the first and second landing, rate of force development experienced no change (P > 0.62), landing phase duration decreased (P = 0.01), and time to peak ground reaction force increased (P 0.12). Interpretation The current results have important implications for the future assessment of ACL injury risk behaviors. Rate of force development remained unchanged between first and second landings from equivalent fall height, while time to peak reaction force increased during the second landing. Neither factor was dependent on the total time duration of landing phase, which decreased during the second landing. Shorter time to peak force may increase ligament strain and better represent the abrupt joint loading that is associated with ACL injury risk. PMID:23899938

Ground beetles (Coleoptera, Carabidae) of the Hanford Nuclear Site in south-central Washington State.

Science.gov (United States)

Looney, Chris; Zack, Richard S; Labonte, James R

2014-01-01

Carabidae) collected from the Hanford Nuclear Reservation and Hanford National Monument (together the Hanford Site), which is located in south-central Washington State. The Site is a relatively undisturbed relict of the shrub-steppe habitat present throughout much of the western Columbia Basin before the westward expansion of the United States. Species, localities, months of capture, and capture method are reported for field work conducted between 1994 and 2002. Most species were collected using pitfall traps, although other capture methods were employed. Trapping results indicate the Hanford Site supports a diverse ground beetle community, with over 90% of the 92 species captured native to North America. Four species collected during the study period are newly recorded for Washington State: Bembidion diligens Casey, Calosoma obsoletum Say, Pseudaptinus rufulus (LeConte), and Stenolophus lineola (Fabricius). Based on these data, the Site maintains a diverse ground beetle fauna and, due to its size and diversity of habitats, is an important repository of shrub-steppe biodiversity.

Classification of matrix-product ground states corresponding to one-dimensional chains of two-state sites of nearest neighbor interactions

International Nuclear Information System (INIS)

Fatollahi, Amir H.; Khorrami, Mohammad; Shariati, Ahmad; Aghamohammadi, Amir

2011-01-01

A complete classification is given for one-dimensional chains with nearest-neighbor interactions having two states in each site, for which a matrix product ground state exists. The Hamiltonians and their corresponding matrix product ground states are explicitly obtained.

Suppression of resonance Raman scattering via ground state depletion towards sub-diffraction-limited label-free microscopy

NARCIS (Netherlands)

Rieger, S.; Fischedick, M.; Boller, Klaus J.; Fallnich, Carsten

2016-01-01

We report on the first experimental demonstration of the suppression of spontaneous Raman scattering via ground state depletion. The concept of Raman suppression can be used to achieve sub-diffraction-limited resolution in label-free microscopy by exploiting spatially selective signal suppression

Dissociation energy of the ground state of NaH

International Nuclear Information System (INIS)

Huang, Hsien-Yu; Lu, Tsai-Lien; Whang, Thou-Jen; Chang, Yung-Yung; Tsai, Chin-Chun

2010-01-01

The dissociation energy of the ground state of NaH was determined by analyzing the observed near dissociation rovibrational levels. These levels were reached by stimulated emission pumping and fluorescence depletion spectroscopy. A total of 114 rovibrational levels in the ranges 9≤v '' ≤21 and 1≤J '' ≤14 were assigned to the X 1 Σ + state of NaH. The highest vibrational level observed was only about 40 cm -1 from the dissociation limit in the ground state. One quasibound state, above the dissociation limit and confined by the centrifugal barrier, was observed. Determining the vibrational quantum number at dissociation v D from the highest four vibrational levels yielded the dissociation energy D e =15 815±5 cm -1 . Based on new observations and available data, a set of Dunham coefficients and the rotationless Rydberg-Klein-Rees curve were constructed. The effective potential curve and the quasibound states were discussed.

The ground state tunneling splitting and the zero point energy of malonaldehyde: a quantum Monte Carlo determination.

Science.gov (United States)

Viel, Alexandra; Coutinho-Neto, Maurício D; Manthe, Uwe

2007-01-14

Quantum dynamics calculations of the ground state tunneling splitting and of the zero point energy of malonaldehyde on the full dimensional potential energy surface proposed by Yagi et al. [J. Chem. Phys. 1154, 10647 (2001)] are reported. The exact diffusion Monte Carlo and the projection operator imaginary time spectral evolution methods are used to compute accurate benchmark results for this 21-dimensional ab initio potential energy surface. A tunneling splitting of 25.7+/-0.3 cm-1 is obtained, and the vibrational ground state energy is found to be 15 122+/-4 cm-1. Isotopic substitution of the tunneling hydrogen modifies the tunneling splitting down to 3.21+/-0.09 cm-1 and the vibrational ground state energy to 14 385+/-2 cm-1. The computed tunneling splittings are slightly higher than the experimental values as expected from the potential energy surface which slightly underestimates the barrier height, and they are slightly lower than the results from the instanton theory obtained using the same potential energy surface.

Regionalization of ground motion attenuation in the conterminous United States

International Nuclear Information System (INIS)

Chung, D.H.; Bernreuter, D.L.

1979-01-01

Attenuation results from geometric spreading and from absorption. The former is almost independent of crustal geology or physiographic region. The latter depends strongly on crustal geology and the state of the earth's upper mantle. Except for very high-frequency waves, absorption does not affect ground motion at distances less than 25 to 50 km. Thus, in the near-field zone, the attenuation in the eastern United States will be similar to that in the western United States. Most of the differences in ground motion can be accounted for by differences in attenuation caused by differences in absorption. The other important factor is that for some Western earthquakes the fault breaks the earth's surface, resulting in larger ground motion. No Eastern earthquakes are known to have broken the earth's surface by faulting. The stress drop of Eastern earthquakes may be higher than for Western earthquakes of the same seismic moment, which would affect the high-frequency spectral content. This factor is believed to be of much less significance than differences in absorption in explaining the differences in ground motion between the East and the West. 6 figures

Ab initio calculation atomics ground state wave function for interactions Ion- Atom

International Nuclear Information System (INIS)

Shojaee, F.; Bolori zadeh, M. A.

2007-01-01

Ab initio calculation atomics ground state wave function for interactions Ion- Atom Atomic wave function expressed in a Slater - type basis obtained within Roothaan- Hartree - Fock for the ground state of the atoms He through B. The total energy is given for each atom.

Relativistic configuration interaction calculation on the ground and excited states of iridium monoxide

International Nuclear Information System (INIS)

Suo, Bingbing; Yu, Yan-Mei; Han, Huixian

2015-01-01

We present the fully relativistic multi-reference configuration interaction calculations of the ground and low-lying excited electronic states of IrO for individual spin-orbit component. The lowest-lying state is calculated for Ω = 1/2, 3/2, 5/2, and 7/2 in order to clarify the ground state of IrO. Our calculation suggests that the ground state is of Ω = 1/2, which is highly mixed with 4 Σ − and 2 Π states in Λ − S notation. The two low-lying states 5/2 and 7/2 are nearly degenerate with the ground state and locate only 234 and 260 cm −1 above, respectively. The equilibrium bond length 1.712 Å and the harmonic vibrational frequency 903 cm −1 of the 5/2 state are close to the experimental measurement of 1.724 Å and 909 cm −1 , which suggests that the 5/2 state should be the low-lying state that contributes to the experimental spectra. Moreover, the electronic states that give rise to the observed transition bands are assigned for Ω = 5/2 and 7/2 in terms of the obtained excited energies and oscillator strengths

Calculation of ground state deformation of even-even rare-earth nuclei in sdg interacting boson model

International Nuclear Information System (INIS)

Wang Baolin

1995-01-01

The analytical calculation of the nuclear ground state deformation of the even-even isotopes in the rare-earth region is given by utilizing the intrinsic states of the sdg interacting boson model. It is compared systematically with the reported theoretical and experimental results. It is shown that the sdg interacting boson model is a reasonable scheme for the description of even-even nuclei deformation

Rearrangements in ground and excited states

CERN Document Server

de Mayo, Paul

1980-01-01

Rearrangements in Ground and Excited States, Volume 2 covers essays on the theoretical approach of rearrangements; the rearrangements involving boron; and the molecular rearrangements of organosilicon compounds. The book also includes essays on the polytopal rearrangement at phosphorus; the rearrangement in coordination complexes; and the reversible thermal intramolecular rearrangements of metal carbonyls. Chemists and people involved in the study of rearrangements will find the book invaluable.

Hyperspherical calculations with Skyrme-like forces

International Nuclear Information System (INIS)

Navarro, J.

1975-11-01

The first approximation of the hyperspherical harmonic method is used to describe in a unified way the ground state and the breathing mode of several doubly-magic nuclei with Skyrme-like forces. A comparison is made with other methods [fr

A Rigorous Investigation on the Ground State of the Penson-Kolb Model

Science.gov (United States)

Yang, Kai-Hua; Tian, Guang-Shan; Han, Ru-Qi

2003-05-01

By using either numerical calculations or analytical methods, such as the bosonization technique, the ground state of the Penson-Kolb model has been previously studied by several groups. Some physicists argued that, as far as the existence of superconductivity in this model is concerned, it is canonically equivalent to the negative-U Hubbard model. However, others did not agree. In the present paper, we shall investigate this model by an independent and rigorous approach. We show that the ground state of the Penson-Kolb model is nondegenerate and has a nonvanishing overlap with the ground state of the negative-U Hubbard model. Furthermore, we also show that the ground states of both the models have the same good quantum numbers and may have superconducting long-range order at the same momentum q = 0. Our results support the equivalence between these models. The project partially supported by the Special Funds for Major State Basic Research Projects (G20000365) and National Natural Science Foundation of China under Grant No. 10174002

Ground reaction forces in shallow water running are affected by immersion level, running speed and gender.

Science.gov (United States)

Haupenthal, Alessandro; Fontana, Heiliane de Brito; Ruschel, Caroline; dos Santos, Daniela Pacheco; Roesler, Helio

2013-07-01

To analyze the effect of depth of immersion, running speed and gender on ground reaction forces during water running. Controlled laboratory study. Twenty adults (ten male and ten female) participated by running at two levels of immersion (hip and chest) and two speed conditions (slow and fast). Data were collected using an underwater force platform. The following variables were analyzed: vertical force peak (Fy), loading rate (LR) and anterior force peak (Fx anterior). Three-factor mixed ANOVA was used to analyze data. Significant effects of immersion level, speed and gender on Fy were observed, without interaction between factors. Fy was greater when females ran fast at the hip level. There was a significant increase in LR with a reduction in the level of immersion regardless of the speed and gender. No effect of speed or gender on LR was observed. Regarding Fx anterior, significant interaction between speed and immersion level was found: in the slow condition, participants presented greater values at chest immersion, whereas, during the fast running condition, greater values were observed at hip level. The effect of gender was only significant during fast water running, with Fx anterior being greater in the men group. Increasing speed raised Fx anterior significantly irrespective of the level of immersion and gender. The magnitude of ground reaction forces during shallow water running are affected by immersion level, running speed and gender and, for this reason, these factors should be taken into account during exercise prescription. Copyright © 2012 Sports Medicine Australia. Published by Elsevier Ltd. All rights reserved.

Interplay between tensor force and deformation in even–even nuclei

Energy Technology Data Exchange (ETDEWEB)

Bernard, Rémi N., E-mail: rbernard@ugr.es; Anguiano, Marta

2016-09-15

In this work we study the effect of the nuclear tensor force on properties related with deformation. We focus on isotopes in the Mg, Si, S, Ar, Sr and Zr chains within the Hartree–Fock–Bogoliubov theory using the D1ST2a Gogny interaction. Contributions to the tensor energy in terms of saturated and unsaturated subshells are analyzed. Like–particle and proton–neutron parts of the tensor term are independently examinated. We found that the tensor term may considerably modify the potential energy landscapes and change the ground state shape. We analyze too how the pairing characteristics of the ground state change when the tensor force is included.

Exponentially Biased Ground-State Sampling of Quantum Annealing Machines with Transverse-Field Driving Hamiltonians.

Science.gov (United States)

Mandrà, Salvatore; Zhu, Zheng; Katzgraber, Helmut G

2017-02-17

We study the performance of the D-Wave 2X quantum annealing machine on systems with well-controlled ground-state degeneracy. While obtaining the ground state of a spin-glass benchmark instance represents a difficult task, the gold standard for any optimization algorithm or machine is to sample all solutions that minimize the Hamiltonian with more or less equal probability. Our results show that while naive transverse-field quantum annealing on the D-Wave 2X device can find the ground-state energy of the problems, it is not well suited in identifying all degenerate ground-state configurations associated with a particular instance. Even worse, some states are exponentially suppressed, in agreement with previous studies on toy model problems [New J. Phys. 11, 073021 (2009)NJOPFM1367-263010.1088/1367-2630/11/7/073021]. These results suggest that more complex driving Hamiltonians are needed in future quantum annealing machines to ensure a fair sampling of the ground-state manifold.

The significant role of covalency in determining the ground state of cobalt phthalocyanines molecule

Directory of Open Access Journals (Sweden)

Jing Zhou

2016-03-01

Full Text Available To shed some light on the metal 3d ground state configuration of cobalt phthalocyanines system, so far in debate, we present an investigation by X-ray absorption spectroscopy (XAS at Co L2,3 edge and theoretical calculation. The density functional theory calculations reveal highly anisotropic covalent bond between central cobalt ion and nitrogen ligands, with the dominant σ donor accompanied by weak π-back acceptor interaction. Our combined experimental and theoretical study on the Co-L2,3 XAS spectra demonstrate a robust ground state of 2A1g symmetry that is built from 73% 3d7 character and 27% 3 d 8 L ¯ ( L ¯ denotes a ligand hole components, as the first excited-state with 2Eg symmetry lies about 158 meV higher in energy. The effect of anisotropic and isotropic covalency on the ground state was also calculated and the results indicate that the ground state with 2A1g symmetry is robust in a large range of anisotropic covalent strength while a transition of ground state from 2A1g to 2Eg configuration when isotropic covalent strength increases to a certain extent. Here, we address a significant anisotropic covalent effect of short Co(II-N bond on the ground state and suggest that it should be taken into account in determining the ground state of analogous cobalt complexes.

Nuclear quadrupole moment of the 99Tc ground state

International Nuclear Information System (INIS)

Errico, Leonardo; Darriba, German; Renteria, Mario; Tang Zhengning; Emmerich, Heike; Cottenier, Stefaan

2008-01-01

By combining first-principles calculations and existing nuclear magnetic resonance (NMR) experiments, we determine the quadrupole moment of the 9/2 + ground state of 99 Tc to be (-)0.14(3)b. This confirms the value of -0.129(20)b, which is currently believed to be the most reliable experimental determination, and disagrees with two earlier experimental values. We supply ab initio calculated electric-field gradients for Tc in YTc 2 and ZrTc 2 . If this calculated information would be combined with yet to be performed Tc-NMR experiments in these compounds, the error bar on the 99 Tc ground state quadrupole moment could be further reduced

Measurement of the ground-state hyperfine splitting of antihydrogen

CERN Document Server

Juhász, B; Federmann, S

2011-01-01

The ASACUSA collaboration at the Antiproton Decelerator of CERN is planning to measure the ground-state hyperfine splitting of antihydrogen using an atomic beam line, consisting of a cusp trap as a source of partially polarized antihydrogen atoms, a radiofrequency spin-flip cavity, a superconducting sextupole magnet as spin analyser, and an antihydrogen detector. This will be a measurement of the antiproton magnetic moment, and also a test of the CPT invariance. Monte Carlo simulations predict that the antihydrogen ground-state hyperfine splitting can be determined with a relative precision of ~10−7. The first preliminary measurements of the hyperfine transitions will start in 2011.

Ground reaction forces and frictional demands during stair descent: effects of age and illumination.

Science.gov (United States)

Christina, Kathryn A; Cavanagh, Peter R

2002-04-01

Stair descent is an inherently risky and demanding task that older adults often encounter in everyday life. It is believed that slip between the foot or shoe sole and the stair surface may play a role in stair related falls, however, there are no reports on slip resistance requirements for stair descent. The aim of this study was to determine the required coefficient of friction (RCOF) necessary for safe stair descent in 12 young and 12 older adults, under varied illuminance conditions. The RCOF during stair descent was found to be comparable in magnitude and time to that for overground walking, and thus, with adequate footwear and dry stair surfaces, friction does not appear to be a major determinant of stair safety. Illuminance level had little effect on the dependent variables quantified in this study. However, the older participants demonstrated safer strategies than the young during stair descent, as reflected by differences in the ground reaction forces and lower RCOF.

Electron scattering from the ground state of mercury

International Nuclear Information System (INIS)

Fursa, D.; Bray, I.

2000-01-01

Full text: Close-coupling calculations have been performed for electron scattering from the ground state of mercury. We have used non-relativistic convergent close-coupling computer code with only minor modifications in order to account for the most prominent relativistic effects. These are the relativistic shift effect and singlet-triplet mixing. Very good agreement with measurements of differential cross sections for elastic scattering and excitation of 6s6p 1 P state at all energies is obtained. It is well recognised that a consistent approach to electron scattering from heavy atoms (like mercury, with nuclear charge Z=80) must be based on a fully relativistic Dirac equations based technique. While development of such technique is under progress in our group, the complexity of the problem ensures that results will not be available in the near future. On other hand, there is considerable interest in reliable theoretical results for electron scattering from heavy atoms from both applications and the need to interpret existing experimental data. This is particularly the case for mercury, which is the major component in fluorescent lighting devices and has been the subject of intense experimental study since nineteen thirties. Similarly to our approach for alkaline-earth atoms we use a model of two valence electrons above an inert Hartree-Fock core to describe the mercury atom. Note that this model does not account for any core excited states which are present in the mercury discrete spectrum. The major effect of missing core-excited states is substantial underestimation of the static dipole polarizability of the mercury ground state (34 a.u.) and consequent underestimation of the forward scattering elastic cross sections. We correct for this by adding in the scattering calculations a phenomenological polarization potential. In order to obtain correct ground state ionization energy for mercury one has to account for the relativistic shift effect. We model this

A New Proxy Measurement Algorithm with Application to the Estimation of Vertical Ground Reaction Forces Using Wearable Sensors.

Science.gov (United States)

Guo, Yuzhu; Storm, Fabio; Zhao, Yifan; Billings, Stephen A; Pavic, Aleksandar; Mazzà, Claudia; Guo, Ling-Zhong

2017-09-22

Measurement of the ground reaction forces (GRF) during walking is typically limited to laboratory settings, and only short observations using wearable pressure insoles have been reported so far. In this study, a new proxy measurement method is proposed to estimate the vertical component of the GRF (vGRF) from wearable accelerometer signals. The accelerations are used as the proxy variable. An orthogonal forward regression algorithm (OFR) is employed to identify the dynamic relationships between the proxy variables and the measured vGRF using pressure-sensing insoles. The obtained model, which represents the connection between the proxy variable and the vGRF, is then used to predict the latter. The results have been validated using pressure insoles data collected from nine healthy individuals under two outdoor walking tasks in non-laboratory settings. The results show that the vGRFs can be reconstructed with high accuracy (with an average prediction error of less than 5.0%) using only one wearable sensor mounted at the waist (L5, fifth lumbar vertebra). Proxy measures with different sensor positions are also discussed. Results show that the waist acceleration-based proxy measurement is more stable with less inter-task and inter-subject variability than the proxy measures based on forehead level accelerations. The proposed proxy measure provides a promising low-cost method for monitoring ground reaction forces in real-life settings and introduces a novel generic approach for replacing the direct determination of difficult to measure variables in many applications.

A New Proxy Measurement Algorithm with Application to the Estimation of Vertical Ground Reaction Forces Using Wearable Sensors

Directory of Open Access Journals (Sweden)

Yuzhu Guo

2017-09-01

Full Text Available Measurement of the ground reaction forces (GRF during walking is typically limited to laboratory settings, and only short observations using wearable pressure insoles have been reported so far. In this study, a new proxy measurement method is proposed to estimate the vertical component of the GRF (vGRF from wearable accelerometer signals. The accelerations are used as the proxy variable. An orthogonal forward regression algorithm (OFR is employed to identify the dynamic relationships between the proxy variables and the measured vGRF using pressure-sensing insoles. The obtained model, which represents the connection between the proxy variable and the vGRF, is then used to predict the latter. The results have been validated using pressure insoles data collected from nine healthy individuals under two outdoor walking tasks in non-laboratory settings. The results show that the vGRFs can be reconstructed with high accuracy (with an average prediction error of less than 5.0% using only one wearable sensor mounted at the waist (L5, fifth lumbar vertebra. Proxy measures with different sensor positions are also discussed. Results show that the waist acceleration-based proxy measurement is more stable with less inter-task and inter-subject variability than the proxy measures based on forehead level accelerations. The proposed proxy measure provides a promising low-cost method for monitoring ground reaction forces in real-life settings and introduces a novel generic approach for replacing the direct determination of difficult to measure variables in many applications.

Ground-water monitoring compliance projects for Hanford Site facilities: Annual progress report for 1987

International Nuclear Information System (INIS)

Hall, S.H.

1988-09-01

This report describes progress during 1987 of five Hanford Site ground water monitoring projects. Four of these projects are being conducted according to regulations based on the federal Resource Conservation and Recovery Act of 1976 and the state Hazardous Waste Management Act. The fifth project is being conducted according to regulations based on the state Solid Waste Management Act. The five projects discussed herein are: 300 Area Process Trenches; 183-H Solar Evaporation Basins; 200 Areas Low-Level Burial Grounds; Nonradioactive Dangerous Waste Landfill; Solid Waste Landfill. For each of the projects, there are included, as applicable, discussions of monitoring well installations, water-table measurements, background and/or downgradient water quality and results of chemical analysis, and extent and rate of movement of contaminant plumes. 14 refs., 30 figs., 13 tabs

Effect of gender, cadence, and water immersion on ground reaction forces during stationary running.

Science.gov (United States)

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

2012-05-01

Controlled laboratory study. To analyze the vertical and anteroposterior components of the ground reaction force during stationary running performed in water and on dry land, focusing on the effect of gender, level of immersion, and cadence. Stationary running, as a fundamental component of aquatic rehabilitation and training protocols, is little explored in the literature with regard to biomechanical variables, which makes it difficult to determine and control the mechanical load acting on the individuals. Twenty-two subjects performed 1 minute of stationary running on land, immersed to the hip, and immersed to the chest at 3 different cadences: 90 steps per minute, 110 steps per minute, and 130 steps per minute. Force data were acquired with a force plate, and the variables were vertical peak (Fy), loading rate (LR), anterior peak (Fx anterior), and posterior peak (Fx posterior). Data were normalized to subjects' body weight (BW) and analyzed using repeated-measures analysis of variance. Fy ranged from 0.98 to 2.11 BW, LR ranged from 5.38 to 11.52 BW/s, Fx anterior ranged from 0.07 to 0.14 BW, and Fx posterior ranged from 0.06 to 0.09 BW. The gender factor had no effect on the variables analyzed. A significant interaction between level of immersion and cadence was observed for Fy, Fx anterior, and Fx posterior. On dry land, Fy increased with increasing cadence, whereas in water this effect was seen only between 90 steps per minute and the 2 higher cadences. The higher the level of immersion, the lower the magnitude of Fy. LR was reduced under both water conditions and increased with increasing cadence, regardless of the level of immersion. Ground reaction forces during stationary running are similar between genders. Fy and LR are lower in water, though the values are increased at higher cadences.

Quantum ground state and single-phonon control of a mechanical resonator.

Science.gov (United States)

O'Connell, A D; Hofheinz, M; Ansmann, M; Bialczak, Radoslaw C; Lenander, M; Lucero, Erik; Neeley, M; Sank, D; Wang, H; Weides, M; Wenner, J; Martinis, John M; Cleland, A N

2010-04-01

Quantum mechanics provides a highly accurate description of a wide variety of physical systems. However, a demonstration that quantum mechanics applies equally to macroscopic mechanical systems has been a long-standing challenge, hindered by the difficulty of cooling a mechanical mode to its quantum ground state. The temperatures required are typically far below those attainable with standard cryogenic methods, so significant effort has been devoted to developing alternative cooling techniques. Once in the ground state, quantum-limited measurements must then be demonstrated. Here, using conventional cryogenic refrigeration, we show that we can cool a mechanical mode to its quantum ground state by using a microwave-frequency mechanical oscillator-a 'quantum drum'-coupled to a quantum bit, which is used to measure the quantum state of the resonator. We further show that we can controllably create single quantum excitations (phonons) in the resonator, thus taking the first steps to complete quantum control of a mechanical system.

A Ground State Tri-pí-Methane Rearrangement

Czech Academy of Sciences Publication Activity Database

Zimmerman, H. E.; Církva, Vladimír; Jiang, L.

2000-01-01

Roč. 41, č. 49 (2000), s. 9585-9587 ISSN 0040-4039 Institutional research plan: CEZ:AV0Z4072921 Keywords : tri-pi-methane * ground state Subject RIV: CC - Organic Chemistry Impact factor: 2.558, year: 2000

Many electron variational ground state of the two dimensional Anderson lattice

International Nuclear Information System (INIS)

Zhou, Y.; Bowen, S.P.; Mancini, J.D.

1991-02-01

A variational upper bound of the ground state energy of two dimensional finite Anderson lattices is determined as a function of lattice size (up to 16 x 16). Two different sets of many-electron basis vectors are used to determine the ground state for all values of the coulomb integral U. This variational scheme has been successfully tested for one dimensional models and should give good estimates in two dimensions

Sub-Doppler spectroscopy of thioformaldehyde: Excited state perturbations and evidence for rotation-induced vibrational mixing in the ground state

International Nuclear Information System (INIS)

Clouthier, D.J.; Huang, G.; Adam, A.G.; Merer, A.J.

1994-01-01

High-resolution intracavity dye laser spectroscopy has been used to obtain sub-Doppler spectra of transitions to 350 rotational levels in the 4 1 0 band of the A 1 A 2 --X 1 A 1 electronic transition of thioformaldehyde. Ground state combination differences from the sub-Doppler spectra, combined with microwave and infrared data, have been used to improve the ground state rotational and centrifugal distortion constants of H 2 CS. The upper state shows a remarkable number of perturbations. The largest of these are caused by nearby triplet levels, with matrix elements of 0.05--0.15 cm -1 . A particularly clear singlet--triplet avoided crossing in K a ' = 7 has been shown to be caused by interaction with the F 1 component of the 3 1 6 2 vibrational level of the a 3 A 2 state. At least 53% of the S 1 levels show evidence of very small perturbations by high rovibronic levels of the ground state. The number of such perturbations is small at low J, but increases rapidly beyond J=5 such that 40%--80% of the observed S 1 levels of any given J are perturbed by ground state levels. Model calculations show that the density and J dependence of the number of perturbed levels can be explained if there is extensive rotation-induced mixing of the vibrational levels in the ground state

Influences of Athletic Footwear on Ground Reaction Forces During A Sidestep Cutting Maneuver on Artificial Turf

Directory of Open Access Journals (Sweden)

Jacob R. Gdovin

2018-04-01

Full Text Available Background: Recreational athletes can select their desired footwear based on personal preferences of shoe properties such as comfort and weight. Commonly worn running shoes and cleated footwear with similar stud geometry and distribution are worn when performing sport-specific tasks such as a side-step cutting maneuver (SCM in soccer and American football (hereafter, referred to as football. The effects of such footwear on injury mechanics have been documented with less being known regarding their effect on performance. Objective: The purpose of this study was to examine performance differences including peak ground reaction forces (pGRF, time-to-peak ground reaction forces (tpGRF and the rate of force development (RFD between football cleats (FB, soccer cleats (SOC, and traditional running sneakers (RUN during the braking and propulsive phases of a SCM. Methodology: Eleven recreationally active males who participated in football and/or soccer-related activities at the time of testing completed the study. A 1 x 3 [1 Condition (SCM x 3 Footwear (RUN, FB, SOC] repeated measures ANOVA was utilized to analyze the aforementioned variables. Results: There were no significant differences (p > 0.05 between footwear conditions when comparing pGRF, tpGRF, or RFD in either the braking or propulsive phases. Conclusion: The results suggest that the studded and non-studded footwear allowed athletes to generate similar forces over a given time frame when performing a SCM.

Structure and magnetic ground states of spin-orbit coupled compound alpha-RuCl3

Science.gov (United States)

Banerjee, Arnab; Bridges, Craig; Yan, Jiaqiang; Mandrus, David; Stone, Matthew; Aczel, Adam; Li, Ling; Yiu, Yuen; Lumsden, Mark; Chakoumakos, Bryan; Tennant, Alan; Nagler, Stephen

2015-03-01

The layered material alpha-RuCl3 is composed of stacks of weakly coupled honeycomb lattices of octahedrally coordinated Ru3 + ions. The Ru ion ground state has 5 d electrons in the low spin state, with spin-orbit coupling very strong compared to other terms in the single ion Hamiltonian. The material is therefore an excellent candidate for investigating possible Heisenberg-Kitaev physics. In addition, this compound is very amenable to investigation by neutron scattering to explore the magnetic ground state and excitations in detail. In this talk, we discuss the synthesis of phase-pure alpha-RuCl3 and the characterization of the magnetization, susceptibility, and heat-capacity. We also report neutron diffraction on both powder and single crystal alpha-RuCl3, identifying the low temperature magnetic order observed in the material. The results, when compared to theoretical calculations, shed light on the relative importance of Kitaev and Heisenberg terms in the Hamiltonian. The research is supported by the DOE BES Scientific User Facility Division.

Ground-state properties of a supersymmetric fermion chain

International Nuclear Information System (INIS)

Fendley, Paul; Hagendorf, Christian

2011-01-01

We analyze the ground state of a strongly interacting fermion chain with a supersymmetry. We conjecture a number of exact results, such as a hidden duality between weak and strong couplings. By exploiting a scale-free property of the perturbative expansions, we find exact expressions for the order parameters, yielding the critical exponents. We show that the ground state of this fermion chain and another model in the same universality class, the XYZ chain along a line of couplings, are both written in terms of the same polynomials. We demonstrate this explicitly for up to N = 24 sites and provide consistency checks for large N. These polynomials satisfy a recursion relation related to the Painlevé VI differential equation and, using a scale-free property of these polynomials, we derive a simple and exact formula for their N→∞ limit

Non-degenerated Ground States and Low-degenerated Excited States in the Antiferromagnetic Ising Model on Triangulations

Science.gov (United States)

Jiménez, Andrea

2014-02-01

We study the unexpected asymptotic behavior of the degeneracy of the first few energy levels in the antiferromagnetic Ising model on triangulations of closed Riemann surfaces. There are strong mathematical and physical reasons to expect that the number of ground states (i.e., degeneracy) of the antiferromagnetic Ising model on the triangulations of a fixed closed Riemann surface is exponential in the number of vertices. In the set of plane triangulations, the degeneracy equals the number of perfect matchings of the geometric duals, and thus it is exponential by a recent result of Chudnovsky and Seymour. From the physics point of view, antiferromagnetic triangulations are geometrically frustrated systems, and in such systems exponential degeneracy is predicted. We present results that contradict these predictions. We prove that for each closed Riemann surface S of positive genus, there are sequences of triangulations of S with exactly one ground state. One possible explanation of this phenomenon is that exponential degeneracy would be found in the excited states with energy close to the ground state energy. However, as our second result, we show the existence of a sequence of triangulations of a closed Riemann surface of genus 10 with exactly one ground state such that the degeneracy of each of the 1st, 2nd, 3rd and 4th excited energy levels belongs to O( n), O( n 2), O( n 3) and O( n 4), respectively.

Correlation induced paramagnetic ground state in FeAl

Czech Academy of Sciences Publication Activity Database

Mohn, P.; Persson, C.; Blaha, P.; Schwarz, K.; Novák, Pavel; Eschrig, H.

2001-01-01

Roč. 87, č. 19 (2001), s. 196401-1-196401-4 ISSN 0031-9007 Institutional research plan: CEZ:AV0Z1010914 Keywords : FeAl * paramagnetic ground state Subject RIV: BM - Solid Matter Physics ; Magnetism Impact factor: 6.668, year: 2001

Nonspherical atomic ground-state densities and chemical deformation densities from x-ray scattering

International Nuclear Information System (INIS)

Ruedenberg, K.; Schwarz, W.H.E.

1990-01-01

Presuming that chemical insight can be gained from the difference between the molecular electron density and the superposition of the ground-state densities of the atoms in a molecule, it is pointed out that, for atoms with degenerate ground states, an unpromoted ''atom in a molecule'' is represented by a specific ensemble of the degenerate atomic ground-state wave functions and that this ensemble is determined by the anisotropic local surroundings. The resulting atomic density contributions are termed oriented ground state densities, and the corresponding density difference is called the chemical deformation density. The constraints implied by this conceptual approach for the atomic density contributions are formulated and a method is developed for determining them from x-ray scattering data. The electron density of the appropriate promolecule and its x-ray scattering are derived, the determination of the parameters of the promolecule is outlined, and the chemical deformation density is formulated

Construction of ground-state preserving sparse lattice models for predictive materials simulations

Science.gov (United States)

Huang, Wenxuan; Urban, Alexander; Rong, Ziqin; Ding, Zhiwei; Luo, Chuan; Ceder, Gerbrand

2017-08-01

First-principles based cluster expansion models are the dominant approach in ab initio thermodynamics of crystalline mixtures enabling the prediction of phase diagrams and novel ground states. However, despite recent advances, the construction of accurate models still requires a careful and time-consuming manual parameter tuning process for ground-state preservation, since this property is not guaranteed by default. In this paper, we present a systematic and mathematically sound method to obtain cluster expansion models that are guaranteed to preserve the ground states of their reference data. The method builds on the recently introduced compressive sensing paradigm for cluster expansion and employs quadratic programming to impose constraints on the model parameters. The robustness of our methodology is illustrated for two lithium transition metal oxides with relevance for Li-ion battery cathodes, i.e., Li2xFe2(1-x)O2 and Li2xTi2(1-x)O2, for which the construction of cluster expansion models with compressive sensing alone has proven to be challenging. We demonstrate that our method not only guarantees ground-state preservation on the set of reference structures used for the model construction, but also show that out-of-sample ground-state preservation up to relatively large supercell size is achievable through a rapidly converging iterative refinement. This method provides a general tool for building robust, compressed and constrained physical models with predictive power.

Indoor Air Quality In Maine Schools: Report of the Task Force To Examine the Establishment and Implementation of State Standards for Indoor Air Quality in Maine Schools.

Science.gov (United States)

Malcolm, Judith

Asserting that in Maine and across the nation, school buildings are becoming increasingly plagued with indoor air quality (IAQ) problems which contribute to a variety of illnesses in children and adults, this report from a Maine state legislative task force identifies appropriate policies and identifies actions necessary for the prevention and…

Stable π-Extended p -Quinodimethanes: Synthesis and Tunable Ground States

KAUST Repository

Zeng, Zebing

2014-12-18

© 2014 The Chemical Society of Japan and Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim. p-Quinodimethane (p-QDM) is a highly reactive hydrocarbon showing large biradical character in the ground state. It has been demonstrated that incorporation of the p-QDM moiety into an aromatic hydrocarbon framework could lead to new π-conjugated systems with significant biradical character and unique optical, electronic and magnetic properties. On the other hand, the extension of p-QDM is expected to result in molecules with even larger biradical character and higher reactivity. Therefore, the synthesis of stable π-extended p-QDMs is very challenging. In this Personal Account we will briefly discuss different stabilizing strategies and synthetic methods towards stable π-extended p-QDMs with tunable ground states and physical properties, including two types of polycyclic hydrocarbons: (1) tetrabenzo-Tschitschibabin\\'s hydrocarbons, and (2) tetracyano-rylenequinodimethanes. We will discuss how the aromaticity, substituents and steric hindrance play important roles in determining their ground states and properties. Incorporation of the p-quinodimethane moiety into aromatic hydrocarbon frameworks can lead to new π-conjugated systems with significant biradical character and unique optical, electronic and magnetic properties. Furthermore, the extension of p-QDM is expected to result in molecules with even larger biradical character and higher reactivity. In this Personal Account, different stabilizing strategies and synthetic methods towards stable π-extended p-QDMs with tunable ground states and physical properties are briefly discussed, including the roles of aromaticity, substituents and steric hindrance.

Ground states of the massless Derezinski-Gerard model

International Nuclear Information System (INIS)

Ohkubo, Atsushi

2009-01-01

We consider the massless Derezinski-Gerard model introduced by Derezinski and Gerard in 1999. We give a sufficient condition for the existence of a ground state of the massless Derezinski-Gerard model without the assumption that the Hamiltonian of particles has compact resolvent.

Ground State Structure of a Coupled 2-Fermion System in Supersymmetric Quantum Mechanics

Science.gov (United States)

Finster, Felix

1997-05-01

We prove the uniqueness of the ground state for a supersymmetric quantum mechanical system of two fermions and two bosons, which is closely related to theN=1 WZ-model. The proof is constructive and gives detailed information on what the ground state looks like

Cluster expansion for ground states of local Hamiltonians

Directory of Open Access Journals (Sweden)

Alvise Bastianello

2016-08-01

Full Text Available A central problem in many-body quantum physics is the determination of the ground state of a thermodynamically large physical system. We construct a cluster expansion for ground states of local Hamiltonians, which naturally incorporates physical requirements inherited by locality as conditions on its cluster amplitudes. Applying a diagrammatic technique we derive the relation of these amplitudes to thermodynamic quantities and local observables. Moreover we derive a set of functional equations that determine the cluster amplitudes for a general Hamiltonian, verify the consistency with perturbation theory and discuss non-perturbative approaches. Lastly we verify the persistence of locality features of the cluster expansion under unitary evolution with a local Hamiltonian and provide applications to out-of-equilibrium problems: a simplified proof of equilibration to the GGE and a cumulant expansion for the statistics of work, for an interacting-to-free quantum quench.

Deflection of electron beams by ground planes

International Nuclear Information System (INIS)

Fernsler, R.F.; Lampe, M.

1991-01-01

Analytic methods are used to determine the effect of a nearby ground plane on the trajectory of a relativistic electron beam passing through dense gas. The beam is shown to respond to the ground plane in one of two distinct modes, determined by beam current and energy. Low-power beams deflect from the ground plane and tear longitudinally. High-power beams do not deflect or tear but tilt, i.e., the beam axis is no longer parallel to the direction of propagation. This conclusion is reached by computing the net beam force as a superposition of the ''bare'' ground-plane forces, the shielding forces from the beam-generated plasma, the body coupling forces induced by beam tilt, and the force that arises as the beam separates from the plasma. Effects from electromagnetic retardation and ground resistivity are shown to be negligible in typical cases of interest, and the interaction between ground planes and other external forces is discussed as well

Lifetime measurements of the first 2+ states in 104,106Zr: Evolution of ground-state deformations

Directory of Open Access Journals (Sweden)

F. Browne

2015-11-01

Full Text Available The first fast-timing measurements from nuclides produced via the in-flight fission mechanism are reported. The lifetimes of the first 2+ states in 104,106Zr nuclei have been measured via β-delayed γ-ray timing of stopped radioactive isotope beams. An improved precision for the lifetime of the 21+ state in 104Zr was obtained, τ(21+=2.90−20+25 ns, as well as a first measurement of the 21+ state in 106Zr, τ(21+=2.60−15+20 ns, with corresponding reduced transition probabilities of B(E2;21+→0g.s.+=0.39(2 e2b2 and 0.31(1 e2b2, respectively. Comparisons of the extracted ground-state deformations, β2=0.39(1 (104Zr and β2=0.36(1 (106Zr with model calculations indicate a persistence of prolate deformation. The data show that 104Zr is the most deformed of the neutron-rich Zr isotopes measured so far.

Compilation of reports prepared for the Secretary of Energy Advisory Board Task Force on Radioactive Waste Management

International Nuclear Information System (INIS)

1993-11-01

This report contains reports prepared for the Secretary of Energy Advisory Board Task Force on Radioactive Waste Management, from experts in the United States. The contents of the report focus mainly on public opinion, and government policies as perceived by the public

Compilation of reports prepared for the Secretary of Energy Advisory Board Task Force on Radioactive Waste Management

Energy Technology Data Exchange (ETDEWEB)

1993-11-01

This report contains reports prepared for the Secretary of Energy Advisory Board Task Force on Radioactive Waste Management, from experts in the United States. The contents of the report focus mainly on public opinion, and government policies as perceived by the public.

Structural Analysis of Grounding Damages on MS DEXTRA

DEFF Research Database (Denmark)

Pedersen, Preben Terndrup; Simonsen, Bo Cerup; Zhang, Shengming

Sub-task 1.2 of DEXTREMEL deals with development of models for external ship collision and grounding dynamics and for internal ship structure dynamics. In order to get a better overview of the work performed in this task it has been decided to write two reports on the work. One dealing...... with internal and external collision dynamics and the present report which deals with structural analysis of grounding events.The first part of the present report is devoted to an energy balance for raking damage situations.Then follows a numerical study of the forces associated with cutting and crushing...

Transitions between states of labor-force participation among older Israelis

OpenAIRE

Achdut, Leah; Tur-Sinai, Aviad; Troitsky, Rita

2014-01-01

The study examines the labor-force behavior of Israelis at older ages, focusing on the determinants of the transitions between states of labor-force participation between 2005 and 2010. The study uses panel data from the first two waves of the SHARE-Israel longitudinal survey. A multinomial logit model is used to examine the impact of sociodemographic characteristics, health state, and economic resources on labor-force transitions of people aged 50–67. The results emphasize the role of age an...

Long Range Forces between Atomic Impurities in Liquid Helium

International Nuclear Information System (INIS)

Dupont-Roc, J.

2002-01-01

Van der Waals or Casimir interaction between neutral quantum objects in their ground state is known to be universally attractive. This is not necessarily so when these objects are embedded in a polarizable medium. We show that atomic impurities in liquid helium may indeed realize repulsive forces, and even Van der Waals and Casimir forces with different signs. (author)

Global potential energy surface of ground state singlet spin O4

Science.gov (United States)

Mankodi, Tapan K.; Bhandarkar, Upendra V.; Puranik, Bhalchandra P.

2018-02-01

A new global potential energy for the singlet spin state O4 system is reported using CASPT2/aug-cc-pVTZ ab initio calculations. The geometries for the six-dimensional surface are constructed using a novel point generation scheme that employs randomly generated configurations based on the beta distribution. The advantage of this scheme is apparent in the reduction of the number of required geometries for a reasonably accurate potential energy surface (PES) and the consequent decrease in the overall computational effort. The reported surface matches well with the recently published singlet surface by Paukku et al. [J. Chem. Phys. 147, 034301 (2017)]. In addition to the O4 PES, the ground state N4 PES is also constructed using the point generation scheme and compared with the existing PES [Y. Paukku et al., J. Chem. Phys. 139, 044309 (2013)]. The singlet surface is constructed with the aim of studying high energy O2-O2 collisions and predicting collision induced dissociation cross section to be used in simulating non-equilibrium aerothermodynamic flows.

Dynamic Electron Correlation Effects on the Ground State Potential Energy Surface of a Retinal Chromophore Model.

Science.gov (United States)

Gozem, Samer; Huntress, Mark; Schapiro, Igor; Lindh, Roland; Granovsky, Alexander A; Angeli, Celestino; Olivucci, Massimo

2012-11-13

The ground state potential energy surface of the retinal chromophore of visual pigments (e.g., bovine rhodopsin) features a low-lying conical intersection surrounded by regions with variable charge-transfer and diradical electronic structures. This implies that dynamic electron correlation may have a large effect on the shape of the force fields driving its reactivity. To investigate this effect, we focus on mapping the potential energy for three paths located along the ground state CASSCF potential energy surface of the penta-2,4-dieniminium cation taken as a minimal model of the retinal chromophore. The first path spans the bond length alternation coordinate and intercepts a conical intersection point. The other two are minimum energy paths along two distinct but kinetically competitive thermal isomerization coordinates. We show that the effect of introducing the missing dynamic electron correlation variationally (with MRCISD) and perturbatively (with the CASPT2, NEVPT2, and XMCQDPT2 methods) leads, invariably, to a stabilization of the regions with charge transfer character and to a significant reshaping of the reference CASSCF potential energy surface and suggesting a change in the dominating isomerization mechanism. The possible impact of such a correction on the photoisomerization of the retinal chromophore is discussed.

Interim site characterization report and ground-water monitoring program for the Hanford site solid waste landfill

International Nuclear Information System (INIS)

Fruland, R.M.; Hagan, R.A.; Cline, C.S.; Bates, D.J.; Evans, J.C.; Aaberg, R.L.

1989-07-01

Federal and state regulations governing the operation of landfills require utilization of ground-water monitoring systems to determine whether or not landfill operations impact ground water at the point of compliance (ground water beneath the perimeter of the facility). A detection-level ground-water monitoring system was designed, installed, and initiated at the Hanford Site Solid Waste Landfill (SWL). Chlorinated hydrocarbons were detected at the beginning of the ground-water monitoring program and continue to be detected more than 1 year later. The most probable source of the chlorinated hydrocarbons is washwater discharged to the SWL between 1985 and 1987. This is an interim report and includes data from the characterization work that was performed during well installation in 1987, such as field observations, sediment studies, and geophysical logging results, and data from analyses of ground-water samples collected in 1987 and 1988, such as field parameter measurements and chemical analyses. 38 refs., 27 figs., 8 tabs

Ground State Energy of the Modified Nambu-Goto String

Science.gov (United States)

Hadasz, Leszek

We calculate, using zeta function regularization method, semiclassical energy of the Nambu-Goto string supplemented with the boundary, Gauss-Bonnet term in the action and discuss the tachyonic ground state problem.

Ground state energy of the modified Nambu-Goto string

OpenAIRE

Hadasz, Leszek

1997-01-01

We calculate, using zeta function regularization method, semiclassical energy of the Nambu-Goto string supplemented with the boundary, Gauss-Bonnet term in the action and discuss the tachyonic ground state problem.

Ground beef handling and cooking practices in restaurants in eight States.

Science.gov (United States)

Bogard, April K; Fuller, Candace C; Radke, Vincent; Selman, Carol A; Smith, Kirk E

2013-12-01

Eating in table-service restaurants has been implicated as a risk factor for Escherichia coli O157:H7 infection. To explore this association and learn about the prevalence of risky ground beef preparation practices in restaurants, the Environmental Health Specialists Network (EHS-Net) assessed ground beef handling policies and practices in restaurants in California, Colorado, Connecticut, Georgia, Minnesota, New York, Oregon, and Tennessee. Eligible restaurants prepared and served hamburgers. EHS-Net specialists interviewed a restaurant employee with authority over the kitchen (defined as the manager) using a standard questionnaire about food safety policies, hamburger preparation policies, and use of irradiated ground beef. Interviews were followed by observations of ground beef preparation. Data from 385 restaurants were analyzed: 67% of the restaurants were independently owned and 33% were chain restaurants; 75% of the restaurants were sit down, 19% were quick service or fast food, and 6% were cafeteria or buffet restaurants. Eighty-one percent of restaurants reported determining doneness of hamburgers by one or more subjective measures, and 49% reported that they never measure the final cook temperatures of hamburgers. At least two risky ground beef handling practices were observed in 53% of restaurants. Only 1% of restaurants reported purchasing irradiated ground beef, and 29% were unfamiliar with irradiated ground beef. Differences in risky ground beef handling policies and practices were noted for type of restaurant ownership (independently owned versus chain) and type of food service style (sit down versus quick service or fast food). This study revealed the pervasiveness of risky ground beef handling policies and practices in restaurants and the need for educational campaigns targeting food workers and managers. These results highlight the importance of continued efforts to reduce the prevalence of E. coli O157:H7 in ground beef.

Singlet Ground State Magnetism: III Magnetic Excitons in Antiferromagnetic TbP

DEFF Research Database (Denmark)

Knorr, K.; Loidl, A.; Kjems, Jørgen

1981-01-01

The dispersion of the lowest magnetic excitations of the singlet ground state system TbP has been studied in the antiferromagnetic phase by inelastic neutron scattering. The magnetic exchange interaction and the magnetic and the rhombohedral molecular fields have been determined.......The dispersion of the lowest magnetic excitations of the singlet ground state system TbP has been studied in the antiferromagnetic phase by inelastic neutron scattering. The magnetic exchange interaction and the magnetic and the rhombohedral molecular fields have been determined....

Unambiguous assignment of the ground state of a nearly degenerate cluster

International Nuclear Information System (INIS)

Gutsev, G. L.; Khanna, S. N.; Jena, P.

2000-01-01

A synergistic approach that combines first-principles theory and electron photodetachment experiment is shown to be able to uniquely identify the ground state of a nearly degenerate cluster in the gas phase. Additionally, this approach can complement the Stern-Gerlach technique in determining the magnetic moment of small clusters unambiguously. The method, applied to a Fe 3 cluster, reveals its ground state to have a magnetic moment of 10μ B --in contrast with earlier predictions. (c) 2000 The American Physical Society

Environmental Assessment: General Plan-Based Environmental Impact Analysis Process, Laughlin Air Force Base

Science.gov (United States)

2007-05-01

BASED ENVIROMENTAL IMPACT ANALYSIS PROCESS LAUGHLIN AIR FORCE BASE, TEXAS AGENCY: 47th Flying Training Wing (FTW), Laughlin Air Force Base (AFB), Texas...m3 micrograms per cubic meter US United States USACE United States Army Corp of Engineers USC United States Code USCB United States Census Bureau...effects and annoyance in that very few flight operations and ground engine runs occur between 2200 hours and 0700 hours. BMPs include restricting the

Management of ground water and evolving hydrogeologic studies in New Jersey : a heavily urbanized and industrialized state in the northeastern United States

Science.gov (United States)

Leahy, P. Patrick

1985-01-01

New Jersey is the most densely populated and one of the most industrialized states in the United States. An abundance of freshwater and proximity to major northeastern metropolitan centers has facilitated this development. Pumpage of freshwater from all aquifers in the State in 1980 was 730 million gallons per day (2.76 million cubic meters per day).Management and efficient development of the ground-water resources of the State are the responsibility of the New Jersey Department of Environmental Protection. Laws have been enacted and updated by the State legislature to manage water allocation and to control the disposal of hazardous wastes. Present resource management is guided by the New Jersey Water-Supply Master Plan of 1981. Funding for management activities is partially derived from the sale of state-approved bonds.Effective planning and regional management require accurate and up-to-date hydrologic information and analyses. The U.S. Geological Survey, in cooperation with the New Jersey Geological Survey, is conducting three intensive ground-water studies involving the collection and interpretation of hydrologic data to meet the urgent water-management needs of New Jersey. These studies are part of a long-term cooperative program and are funded through the Water-Supply Bond Act of 1981. They began in 1983 and are scheduled to be completed in 1988.The project areas are situated in the New Jersey part of the Atlantic Coastal Plain in and near Atlantic City, Camden, and South River. They range in size from 400 to 1,200 mil (1,040 to 3,120 km2). The studies are designed to define the geology, hydrology, and geochemistry of the local ground-water systems. The results of these studies will enable the State to address more effectively major problems in these areas such as declining water levels, overpumping, saltwater intrusion, and ground-water contamination resulting from the improper disposal of hazardous wastes.Specific objectives of these studies by the U

[Environmental investigation of ground water contamination at Wright-Patterson Air Force Base, Ohio]. Volume 3, Appendix A, Draft standard operating procedures and elements: Sampling and Analysis Plan (SAP): Phase 1, Task 4, Field Investigation, Draft

Energy Technology Data Exchange (ETDEWEB)

1991-10-01

This report presents information concerning field procedures employed during the monitoring, well construction, well purging, sampling, and well logging at the Wright-Patterson Air Force Base. Activities were conducted in an effort to evaluate ground water contamination.

Separable pairing force for relativistic quasiparticle random-phase approximation

International Nuclear Information System (INIS)

Tian Yuan; Ma Zhongyu; Ring, Peter

2009-01-01

We have introduced a separable pairing force, which was adjusted to reproduce the pairing properties of the Gogny force in nuclear matter. This separable pairing force is able to describe in relativistic Hartree-Bogoliubov (RHB) calculations the pairing properties in the ground state of finite nuclei on almost the same footing as the original Gogny interaction. In this work we investigate excited states using the Relativistic Quasiparticle Random-Phase Approximation (RQRPA) with the same separable pairing force. For consistency the Goldstone modes and the convergence with various cutoff parameters in this version of RQRPA are studied. The first excited 2 + states for the chain of Sn isotopes with Z=50 and the chain of isotones with N=82 isotones are calculated in RQRPA together with the 3 - states of Sn isotopes. By comparing our results with experimental data and with the results of the original Gogny force we find that this simple separable pairing interaction is very successful in depicting the pairing properties of vibrational excitations.

The Enemy Below: Preparing Ground Forces for Subterranean Warfare

Science.gov (United States)

2013-12-01

States of America (CSA). Under the command of Lieutenant General (LTG) Ulysses S. Grant, Major General (MG) George Meade’s forces waged a nearly...Additionally, in his statement he noted that General Meade and Grant’s chief engineer regarded the effort as nonsense; that a mine that length had...tomorrow, but we shall certainly change the geography.” Sir Herbert Plumer, 2nd Army Commander44 1. Introduction The Western Front was caught in a

Modeling of the stress-strain state of the ground mass contaminated with peracetic acid

Directory of Open Access Journals (Sweden)

Levenko Anna

2017-01-01

Full Text Available None of the methods described previously provides a solution to the problem that deals with the SSS evaluation of the ground mass which is under the influence of chemically active substances and, in particular, under the influence of peracetic acid. The stress-strain state of the ground mass contaminated with peracetic acid was estimated. Stresses occurring in the ground mass in the natural state were determined after the entry of acid into it and after the chemical fixation of it with sodium silicate. All the parameters of the stress-strain state of the ground mass were obtained under a number of physical and mechanical conditions. It was determined that following the work on the silicatization of the ground mass contaminated with peracetic acid the quantity of strain decreased by 26.11 to 48.9%. The comparison of the results of stress calculations indicates the stress reduction in the ground mass in 1.8 – 2.6 times after its fixing.

Kohn-Sham Theory for Ground-State Ensembles

International Nuclear Information System (INIS)

Ullrich, C. A.; Kohn, W.

2001-01-01

An electron density distribution n(r) which can be represented by that of a single-determinant ground state of noninteracting electrons in an external potential v(r) is called pure-state v -representable (P-VR). Most physical electronic systems are P-VR. Systems which require a weighted sum of several such determinants to represent their density are called ensemble v -representable (E-VR). This paper develops formal Kohn-Sham equations for E-VR physical systems, using the appropriate coupling constant integration. It also derives local density- and generalized gradient approximations, and conditions and corrections specific to ensembles

Ground state structure of a coupled 2-fermion system in supersymmetric quantum mechanics

International Nuclear Information System (INIS)

Finster, F.

1997-01-01

We prove the uniqueness of the ground state for a supersymmetric quantum mechanical system of two fermions and two bosons, which is closely related to the N=1 WZ-model. The proof is constructive and gives detailed information on what the ground state looks like. copyright 1997 Academic Press, Inc

Evidence for forcing-dependent steady states in a turbulent swirling flow.

Science.gov (United States)

Saint-Michel, B; Dubrulle, B; Marié, L; Ravelet, F; Daviaud, F

2013-12-06

We study the influence on steady turbulent states of the forcing in a von Karman flow, at constant impeller speed, or at constant torque. We find that the different forcing conditions change the nature of the stability of the steady states and reveal dynamical regimes that bear similarities to low-dimensional systems. We suggest that this forcing dependence may be applicable to other turbulent systems.

A simple parameter-free wavefunction for the ground state of two-electron atoms

International Nuclear Information System (INIS)

Ancarani, L U; Rodriguez, K V; Gasaneo, G

2007-01-01

We propose a simple and pedagogical wavefunction for the ground state of two-electron atoms which (i) is parameter free (ii) satisfies all two-particle cusp conditions (iii) yields reasonable ground-state energies, including the prediction of a bound state for H - . The mean energy, and other mean physical quantities, is evaluated analytically. The simplicity of the result can be useful as an easy-to-use wavefunction when testing collision models

Trapping cold ground state argon atoms for sympathetic cooling of molecules

OpenAIRE

Edmunds, P. D.; Barker, P. F.

2014-01-01

We trap cold, ground-state, argon atoms in a deep optical dipole trap produced by a build-up cavity. The atoms, which are a general source for the sympathetic cooling of molecules, are loaded in the trap by quenching them from a cloud of laser-cooled metastable argon atoms. Although the ground state atoms cannot be directly probed, we detect them by observing the collisional loss of co-trapped metastable argon atoms using a new type of parametric loss spectroscopy. Using this technique we als...

High spin polarization and the origin of unique ferromagnetic ground state in CuFeSb

International Nuclear Information System (INIS)

Sirohi, Anshu; Saha, Preetha; Gayen, Sirshendu; Gaurav, Abhishek; Jyotsna, Shubhra; Sheet, Goutam; Singh, Chandan K.; Kabir, Mukul; Thakur, Gohil S.; Haque, Zeba; Gupta, L. C.; Ganguli, Ashok K.

2016-01-01

CuFeSb is isostructural to the ferro-pnictide and chalcogenide superconductors and it is one of the few materials in the family that are known to stabilize in a ferromagnetic ground state. Majority of the members of this family are either superconductors or antiferromagnets. Therefore, CuFeSb may be used as an ideal source of spin polarized current in spin-transport devices involving pnictide and the chalcogenide superconductors. However, for that the Fermi surface of CuFeSb needs to be sufficiently spin polarized. In this paper we report direct measurement of transport spin polarization in CuFeSb by spin-resolved Andreev reflection spectroscopy. From a number of measurements using multiple superconducting tips we found that the intrinsic transport spin polarization in CuFeSb is high (∼47%). In order to understand the unique ground state of CuFeSb and the origin of large spin polarization at the Fermi level, we have evaluated the spin-polarized band structure of CuFeSb through first principles calculations. Apart from supporting the observed 47% transport spin polarization, such calculations also indicate that the Sb-Fe-Sb angles and the height of Sb from the Fe plane are strikingly different for CuFeSb than the equivalent parameters in other members of the same family thereby explaining the origin of the unique ground state of CuFeSb.

High spin polarization and the origin of unique ferromagnetic ground state in CuFeSb

Energy Technology Data Exchange (ETDEWEB)

Sirohi, Anshu; Saha, Preetha; Gayen, Sirshendu; Gaurav, Abhishek; Jyotsna, Shubhra; Sheet, Goutam, E-mail: goutam@iisermohali.ac.in [Department of Physical Sciences, Indian Institute of Science Education and Research Mohali, Sector 81, S. A. S. Nagar, Manauli PO 140306 (India); Singh, Chandan K.; Kabir, Mukul [Department of Physics, Indian Institute of Science Education and Research, Pune 411008 (India); Thakur, Gohil S.; Haque, Zeba; Gupta, L. C. [Department of Chemistry, Indian Institute of Technology, New Delhi 110016 (India); Ganguli, Ashok K. [Department of Chemistry, Indian Institute of Technology, New Delhi 110016 (India); Institute of Nano Science & Technology, Mohali 160064 (India)

2016-06-13

CuFeSb is isostructural to the ferro-pnictide and chalcogenide superconductors and it is one of the few materials in the family that are known to stabilize in a ferromagnetic ground state. Majority of the members of this family are either superconductors or antiferromagnets. Therefore, CuFeSb may be used as an ideal source of spin polarized current in spin-transport devices involving pnictide and the chalcogenide superconductors. However, for that the Fermi surface of CuFeSb needs to be sufficiently spin polarized. In this paper we report direct measurement of transport spin polarization in CuFeSb by spin-resolved Andreev reflection spectroscopy. From a number of measurements using multiple superconducting tips we found that the intrinsic transport spin polarization in CuFeSb is high (∼47%). In order to understand the unique ground state of CuFeSb and the origin of large spin polarization at the Fermi level, we have evaluated the spin-polarized band structure of CuFeSb through first principles calculations. Apart from supporting the observed 47% transport spin polarization, such calculations also indicate that the Sb-Fe-Sb angles and the height of Sb from the Fe plane are strikingly different for CuFeSb than the equivalent parameters in other members of the same family thereby explaining the origin of the unique ground state of CuFeSb.

(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.

Guidelines for ground motion definition for the eastern United States

International Nuclear Information System (INIS)

Gwaltney, R.C.; Aramayo, G.A.; Williams, R.T.

1985-06-01

Guidelines for the determination of earthquake ground motion definition for the eastern United States are established here. Both far-field and near-field guidelines are given. The guidelines were based on an extensive review of the current procedures for specifying ground motion in the United States. Both empirical and theoretical procedures were used in establishing the guidelines because of the low seismicity in the eastern United States. Only a few large- to great-sized earthquakes (M/sub s/ > 7.5) have occurred in this region, no evidence of tectonic surface ruptures related to historic or Holocene earthquakes has been found, and no currently active plate boundaries of any kind are known in this region. Very little instrumented data have been gathered in the East. Theoretical procedures are proposed so that in regions of almost no data, a reasonable level of seismic ground motion activity can be assumed. The guidelines are to be used to develop the safe shutdown earthquake (SSE). A new procedure for establishing the operating basis earthquake (OBE) is proposed, in particular for the eastern United States. The OBE would be developed using a probabilistic assessment of the geological conditions and the recurrence of seismic events at a site. These guidelines should be useful in development of seismic design requirements for future reactors. 17 refs., figs., tabs

Transitions between states of labor-force participation among older Israelis.

Science.gov (United States)

Achdut, Leah; Tur-Sinai, Aviad; Troitsky, Rita

2015-03-01

The study examines the labor-force behavior of Israelis at older ages, focusing on the determinants of the transitions between states of labor-force participation between 2005 and 2010. The study uses panel data from the first two waves of the SHARE-Israel longitudinal survey. A multinomial logit model is used to examine the impact of sociodemographic characteristics, health state, and economic resources on labor-force transitions of people aged 50-67. The results emphasize the role of age and poor health in "pushing" older people out of the labor force or "keeping" them there. Spouse's participation is found to encourage individuals to leave the labor force or to refrain from joining it. However, living with a participating spouse is negatively associated with staying out of the labor force, consistent with the dominance of the complementarity of leisure effect found in the literature. Wealth as an economic resource available to individuals for retirement is also found to encourage individuals to leave the labor force or to refrain from joining it.

Construction and study of exact ground states for a class of quantum antiferromagnets

International Nuclear Information System (INIS)

Fannes, M.

1989-01-01

Techniques of quantum probability are used to construct the exact ground states for a class of quantum spin systems in one dimension. This class in particular contains the antiferromagnetic models introduced by various authors under the name of VBS-models. The construction permits a detailed study of these ground states. (A.C.A.S.) [pt

Ground state properties of the bond alternating spin-1/2 anisotropic Heisenberg chain

Directory of Open Access Journals (Sweden)

S. Paul

2017-06-01

Full Text Available Ground state properties, dispersion relations and scaling behaviour of spin gap of a bond alternating spin-1/2 anisotropic Heisenberg chain have been studied where the exchange interactions on alternate bonds are ferromagnetic (FM and antiferromagnetic (AFM in two separate cases. The resulting models separately represent nearest neighbour (NN AFM-AFM and AFM-FM bond alternating chains. Ground state energy has been estimated analytically by using both bond operator and Jordan-Wigner representations and numerically by using exact diagonalization. Dispersion relations, spin gap and several ground state orders have been obtained. Dimer order and string orders are found to coexist in the ground state. Spin gap is found to develop as soon as the non-uniformity in alternating bond strength is introduced in the AFM-AFM chain which further remains non-zero for the AFM-FM chain. This spin gap along with the string orders attribute to the Haldane phase. The Haldane phase is found to exist in most of the anisotropic region similar to the isotropic point.

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

Numerical simulations of oscillating soliton stars: Excited states in spherical symmetry and ground state evolutions in 3D

International Nuclear Information System (INIS)

Balakrishna, Jayashree; Bondarescu, Ruxandra; Daues, Gregory; Bondarescu, Mihai

2008-01-01

Excited state soliton stars are studied numerically for the first time. The stability of spherically symmetric S-branch excited state oscillatons under radial perturbations is investigated using a 1D code. We find that these stars are inherently unstable either migrating to the ground state or collapsing to black holes. Higher excited state configurations are observed to cascade through intermediate excited states during their migration to the ground state. This is similar to excited state boson stars [J. Balakrishna, E. Seidel, and W.-M. Suen, Phys. Rev. D 58, 104004 (1998).]. Ground state oscillatons are then studied in full 3D numerical relativity. Finding the appropriate gauge condition for the dynamic oscillatons is much more challenging than in the case of boson stars. Different slicing conditions are explored, and a customized gauge condition that approximates polar slicing in spherical symmetry is implemented. Comparisons with 1D results and convergence tests are performed. The behavior of these stars under small axisymmetric perturbations is studied and gravitational waveforms are extracted. We find that the gravitational waves damp out on a short time scale, enabling us to obtain the complete waveform. This work is a starting point for the evolution of real scalar field systems with arbitrary symmetries

Induced quadrupolar singlet ground state of praseodymium in a modulated pyrochlore

Science.gov (United States)

van Duijn, J.; Kim, K. H.; Hur, N.; Ruiz-Bustos, R.; Adroja, D. T.; Bridges, F.; Daoud-Aladine, A.; Fernandez-Alonso, F.; Wen, J. J.; Kearney, V.; Huang, Q. Z.; Cheong, S.-W.; Perring, T. G.; Broholm, C.

2017-09-01

The complex structure and magnetism of Pr2 -xBixRu2O7 was investigated by neutron scattering and extended x-ray absorption fine structure. Pr has an approximate doublet ground state and the first excited state is a singlet. While the B -site (Ru) is well ordered throughout, this is not the case for the A -site (Pr/Bi). A broadened distribution for the Pr-O2 bond length at low temperature indicates the Pr environment varies from site to site even for x =0 . The environment about the Bi site is highly disordered ostensibly due to the 6 s lone pairs on Bi3 +. Correspondingly, we find that the non-Kramers doublet ground-state degeneracy, otherwise anticipated for Pr in the pyrochlore structure, is lifted so as to produce a quadrupolar singlet ground state with a spatially varying energy gap. For x =0 , below TN, the Ru sublattice orders antiferromagnetically, with propagation vector k =(0 ,0 ,0 ) as for Y2Ru2O7 . No ordering associated with the Pr sublattice is observed down to 100 mK. The low-energy magnetic response of Pr2 -xBixRu2O7 features a broad spectrum of magnetic excitations associated with inhomogeneous splitting of the Pr quasidoublet ground state. For x =0 (x =0.97 ), the spectrum is temperature dependent (independent). It appears disorder associated with Bi alloying enhances the inhomogeneous Pr crystal-field level splitting so that intersite interactions become irrelevant for x =0.97 . The structural complexity for the A -site may be reflected in the hysteretic uniform magnetization of B -site ruthenium in the Néel phase.

Report of analyses for light hydrocarbons in ground water

International Nuclear Information System (INIS)

Dromgoole, E.L.

1982-04-01

This report contains on microfiche the results of analyses for methane, ethane, propane, and butane in 11,659 ground water samples collected in 47 western and three eastern 1 0 x 2 0 quadrangles of the National Topographic Map Series (Figures 1 and 2), along with a brief description of the analytical technique used and some simple, descriptive statistics. The ground water samples were collected as part of the National Uranium Resource Evaluation (NURE) hydrogeochemical and stream sediment reconnaissance. Further information on the ground water samples can be obtained by consulting the NURE data reports for the individual quadrangles. This information includes (1) measurements characterizing water samples (pH, conductivity, and alkalinity), (2) physical measurements, where applicable (water temperature, well description, and other measurements), and (3) elemental analyses

Relationships Between Countermovement Jump Ground Reaction Forces and Jump Height, Reactive Strength Index, and Jump Time.

Science.gov (United States)

Barker, Leland A; Harry, John R; Mercer, John A

2018-01-01

Barker, LA, Harry, JR, and Mercer, JA. Relationships between countermovement jump ground reaction forces and jump height, reactive strength index, and jump time. J Strength Cond Res 32(1): 248-254, 2018-The purpose of this study was to determine the relationship between ground reaction force (GRF) variables to jump height, jump time, and the reactive strength index (RSI). Twenty-six, Division-I, male, soccer players performed 3 maximum effort countermovement jumps (CMJs) on a dual-force platform system that measured 3-dimensional kinetic data. The trial producing peak jump height was used for analysis. Vertical GRF (Fz) variables were divided into unloading, eccentric, amortization, and concentric phases and correlated with jump height, RSI (RSI = jump height/jump time), and jump time (from start to takeoff). Significant correlations were observed between jump height and RSI, concentric kinetic energy, peak power, concentric work, and concentric displacement. Significant correlations were observed between RSI and jump time, peak power, unload Fz, eccentric work, eccentric rate of force development (RFD), amortization Fz, amortization time, second Fz peak, average concentric Fz, and concentric displacement. Significant correlations were observed between jump time and unload Fz, eccentric work, eccentric RFD, amortization Fz, amortization time, average concentric Fz, and concentric work. In conclusion, jump height correlated with variables derived from the concentric phase only (work, power, and displacement), whereas Fz variables from the unloading, eccentric, amortization, and concentric phases correlated highly with RSI and jump time. These observations demonstrate the importance of countermovement Fz characteristics for time-sensitive CMJ performance measures. Researchers and practitioners should include RSI and jump time with jump height to improve their assessment of jump performance.

Ground water hydrology report: Revision 1, Attachment 3. Final

International Nuclear Information System (INIS)

1996-12-01

This report presents ground water hydrogeologic activities for the Maybell, Colorado, Uranium Mill Tailings Remedial Action Project site. The Department of Energy has characterized the hydrogeology, water quality, and water resources at the site and determined that the proposed remedial action would comply with the requirements of the EPA ground water protection standards

Exact ground-state phase diagrams for the spin-3/2 Blume-Emery-Griffiths model

Energy Technology Data Exchange (ETDEWEB)

Canko, Osman; Keskin, Mustafa [Department of Physics, Erciyes University, 38039 Kayseri (Turkey); Deviren, Bayram [Institute of Science, Erciyes University, 38039 Kayseri (Turkey)], E-mail: keskin@erciyes.edu.tr

2008-05-15

We have calculated the exact ground-state phase diagrams of the spin-3/2 Ising model using the method that was proposed and applied to the spin-1 Ising model by Dublenych (2005 Phys. Rev. B 71 012411). The calculated, exact ground-state phase diagrams on the diatomic and triangular lattices with the nearest-neighbor (NN) interaction have been presented in this paper. We have obtained seven and 15 topologically different ground-state phase diagrams for J>0 and J<0, respectively, on the diatomic lattice and have found the conditions for the existence of uniform and intermediate or non-uniform phases. We have also constructed the exact ground-state phase diagrams of the model on the triangular lattice and found 20 and 59 fundamental phase diagrams for J>0 and J<0, respectively, the conditions for the existence of uniform and intermediate phases have also been found.

Development of State Plan for Career Education in Alabama. Final Report.

Science.gov (United States)

Alabama State Dept. of Education, Montgomery.

This state plan for career education in Alabama describes the first-year objectives and operational procedures of the State Advisory Council for Career Education. Activities of the following six task forces are reported: (1) needs assessment for grades K-12, (2) postsecondary needs assessment, (3) noneducational (business and industry) needs…

Photoionization of furan from the ground and excited electronic states.

Science.gov (United States)

Ponzi, Aurora; Sapunar, Marin; Angeli, Celestino; Cimiraglia, Renzo; Došlić, Nađa; Decleva, Piero

2016-02-28

Here we present a comparative computational study of the photoionization of furan from the ground and the two lowest-lying excited electronic states. The study aims to assess the quality of the computational methods currently employed for treating bound and continuum states in photoionization. For the ionization from the ground electronic state, we show that the Dyson orbital approach combined with an accurate solution of the continuum one particle wave functions in a multicenter B-spline basis, at the density functional theory (DFT) level, provides cross sections and asymmetry parameters in excellent agreement with experimental data. On the contrary, when the Dyson orbitals approach is combined with the Coulomb and orthogonalized Coulomb treatments of the continuum, the results are qualitatively different. In excited electronic states, three electronic structure methods, TDDFT, ADC(2), and CASSCF, have been used for the computation of the Dyson orbitals, while the continuum was treated at the B-spline/DFT level. We show that photoionization observables are sensitive probes of the nature of the excited states as well as of the quality of excited state wave functions. This paves the way for applications in more complex situations such as time resolved photoionization spectroscopy.

Ground-state correlations within a nonperturbative approach

Czech Academy of Sciences Publication Activity Database

De Gregorio, G.; Herko, J.; Knapp, F.; Lo Iudice, N.; Veselý, Petr

2017-01-01

Roč. 95, č. 2 (2017), č. článku 024306. ISSN 2469-9985 R&D Projects: GA ČR GA13-07117S Institutional support: RVO:61389005 Keywords : ground state * harmonic oscillator frequency * space dimensions Subject RIV: BE - Theoretical Physics OBOR OECD: Atomic, molecular and chemical physics (physics of atoms and molecules including collision, interaction with radiation, magnetic resonances, Mössbauer effect) Impact factor: 3.820, year: 2016

Unsteady steady-states: central causes of unintentional force drift.

Science.gov (United States)

Ambike, Satyajit; Mattos, Daniela; Zatsiorsky, Vladimir M; Latash, Mark L

2016-12-01

We applied the theory of synergies to analyze the processes that lead to unintentional decline in isometric fingertip force when visual feedback of the produced force is removed. We tracked the changes in hypothetical control variables involved in single fingertip force production based on the equilibrium-point hypothesis, namely the fingertip referent coordinate (R FT ) and its apparent stiffness (C FT ). The system's state is defined by a point in the {R FT ; C FT } space. We tested the hypothesis that, after visual feedback removal, this point (1) moves along directions leading to drop in the output fingertip force, and (2) has even greater motion along directions that leaves the force unchanged. Subjects produced a prescribed fingertip force using visual feedback and attempted to maintain this force for 15 s after the feedback was removed. We used the "inverse piano" apparatus to apply small and smooth positional perturbations to fingers at various times after visual feedback removal. The time courses of R FT and C FT showed that force drop was mostly due to a drift in R FT toward the actual fingertip position. Three analysis techniques, namely hyperbolic regression, surrogate data analysis, and computation of motor-equivalent and non-motor-equivalent motions, suggested strong covariation in R FT and C FT stabilizing the force magnitude. Finally, the changes in the two hypothetical control variables {R FT ; C FT } relative to their average trends also displayed covariation. On the whole, the findings suggest that unintentional force drop is associated with (a) a slow drift of the referent coordinate that pulls the system toward a low-energy state and (b) a faster synergic motion of R FT and C FT that tends to stabilize the output fingertip force about the slowly drifting equilibrium point.

Exact ground-state phase diagrams for the spin-3/2 Blume-Emery-Griffiths model

International Nuclear Information System (INIS)

Canko, Osman; Keskin, Mustafa; Deviren, Bayram

2008-01-01

We have calculated the exact ground-state phase diagrams of the spin-3/2 Ising model using the method that was proposed and applied to the spin-1 Ising model by Dublenych (2005 Phys. Rev. B 71 012411). The calculated, exact ground-state phase diagrams on the diatomic and triangular lattices with the nearest-neighbor (NN) interaction have been presented in this paper. We have obtained seven and 15 topologically different ground-state phase diagrams for J>0 and J 0 and J<0, respectively, the conditions for the existence of uniform and intermediate phases have also been found

Multi-segment foot kinematics and ground reaction forces during gait of individuals with plantar fasciitis.

Science.gov (United States)

Chang, Ryan; Rodrigues, Pedro A; Van Emmerik, Richard E A; Hamill, Joseph

2014-08-22

Clinically, plantar fasciitis (PF) is believed to be a result and/or prolonged by overpronation and excessive loading, but there is little biomechanical data to support this assertion. The purpose of this study was to determine the differences between healthy individuals and those with PF in (1) rearfoot motion, (2) medial forefoot motion, (3) first metatarsal phalangeal joint (FMPJ) motion, and (4) ground reaction forces (GRF). We recruited healthy (n=22) and chronic PF individuals (n=22, symptomatic over three months) of similar age, height, weight, and foot shape (p>0.05). Retro-reflective skin markers were fixed according to a multi-segment foot and shank model. Ground reaction forces and three dimensional kinematics of the shank, rearfoot, medial forefoot, and hallux segment were captured as individuals walked at 1.35 ms(-1). Despite similarities in foot anthropometrics, when compared to healthy individuals, individuals with PF exhibited significantly (pfoot kinematics and kinetics. Consistent with the theoretical injury mechanisms of PF, we found these individuals to have greater total rearfoot eversion and peak FMPJ dorsiflexion, which may put undue loads on the plantar fascia. Meanwhile, increased medial forefoot plantar flexion at initial contact and decreased propulsive GRF are suggestive of compensatory responses, perhaps to manage pain. Copyright © 2014 Elsevier Ltd. All rights reserved.

Normal ground state of dense relativistic matter in a magnetic field

International Nuclear Information System (INIS)

Gorbar, E. V.; Miransky, V. A.; Shovkovy, I. A.

2011-01-01

The properties of the ground state of relativistic matter in a magnetic field are examined within the framework of a Nambu-Jona-Lasinio model. The main emphasis of this study is the normal ground state, which is realized at sufficiently high temperatures and/or sufficiently large chemical potentials. In contrast to the vacuum state, which is characterized by the magnetic catalysis of chiral symmetry breaking, the normal state is accompanied by the dynamical generation of the chiral shift parameter Δ. In the chiral limit, the value of Δ determines a relative shift of the longitudinal momenta (along the direction of the magnetic field) in the dispersion relations of opposite chirality fermions. We argue that the chirality remains a good approximate quantum number even for massive fermions in the vicinity of the Fermi surface and, therefore, the chiral shift is expected to play an important role in many types of cold dense relativistic matter, relevant for applications in compact stars. The qualitative implications of the revealed structure of the normal ground state on the physics of protoneutron stars are discussed. A noticeable feature of the Δ parameter is that it is insensitive to temperature when T 0 , where μ 0 is the chemical potential, and increases with temperature for T>μ 0 . The latter implies that the chiral shift parameter is also generated in the regime relevant for heavy ion collisions.

Pade approximants for the ground-state energy of closed-shell quantum dots

International Nuclear Information System (INIS)

Gonzalez, A.; Partoens, B.; Peeters, F.M.

1997-08-01

Analytic approximations to the ground-state energy of closed-shell quantum dots (number of electrons from 2 to 210) are presented in the form of two-point Pade approximants. These Pade approximants are constructed from the small- and large-density limits of the energy. We estimated that the maximum error, reached for intermediate densities, is less than ≤ 3%. Within that present approximation the ground-state is found to be unpolarized. (author). 21 refs, 3 figs, 2 tabs

Exact ground-state correlation functions of an atomic-molecular Bose–Einstein condensate model

Science.gov (United States)

Links, Jon; Shen, Yibing

2018-05-01

We study the ground-state properties of an atomic-molecular Bose–Einstein condensate model through an exact Bethe Ansatz solution. For a certain range of parameter choices, we prove that the ground-state Bethe roots lie on the positive real-axis. We then use a continuum limit approach to obtain a singular integral equation characterising the distribution of these Bethe roots. Solving this equation leads to an analytic expression for the ground-state energy. The form of the expression is consistent with the existence of a line of quantum phase transitions, which has been identified in earlier studies. This line demarcates a molecular phase from a mixed phase. Certain correlation functions, which characterise these phases, are then obtained through the Hellmann–Feynman theorem.

Development of a three-dimensional ground-water model of the Hanford Site unconfined aquifer system: FY 1995 status report

International Nuclear Information System (INIS)

Wurstner, S.K.; Thorne, P.D.; Chamness, M.A.; Freshley, M.D.; Williams, M.D.

1995-12-01

A three-dimensional numerical model of ground-water flow was developed for the uppermost unconfined aquifer at the Hanford Site in south-central Washington. Development of the model is supported by the Hanford Site Ground-Water Surveillance Project, managed by the Pacific Northwest National Laboratory, which is responsible for monitoring the sitewide movement of contaminants in ground water beneath the Hanford Site. Two objectives of the Ground-Water Surveillance Project are to (1) identify and quantify existing, emerging, or potential ground-water quality problems, and (2) assess the potential for contaminants to migrate from the Hanford Site through the ground-water pathway. Numerical models of the ground-water flow system are important tools for estimating future aquifer conditions and predicting the movement of contaminants through ground water. The Ground-Water Surveillance Project has supported development and maintenance of a two-dimensional model of the unconfined aquifer. This report describes upgrade of the two-dimensional model to a three-dimensional model. The numerical model is based on a three-dimensional conceptual model that will be continually refined and updated as additional information becomes available. This report presents a description of the three-dimensional conceptual model of ground-water flow in the unconfined aquifer system and then discusses the cur-rent state of the three-dimensional numerical model

Laser photoelectron spectroscopy of MnH - and FeH - : Electronic structures of the metal hydrides, identification of a low-spin excited state of MnH, and evidence for a low-spin ground state of FeH

Science.gov (United States)

Stevens, Amy E.; Feigerle, C. S.; Lineberger, W. C.

1983-05-01

The laser photoelectron spectra of MnH- and MnD-, and FeH- and FeD- are reported. A qualitative description of the electronic structure of the low-spin and high-spin states of the metal hydrides is developed, and used to interpret the spectra. A diagonal transition in the photodetachment to the known high-spin, 7Σ+, ground state of MnH is observed. An intense off-diagonal transition to a state of MnH, at 1725±50 cm-1 excitation energy, is attributed to loss of an antibonding electron from MnH-, to yield a low-spin quintet state of MnH. For FeH- the photodetachment to the ground state is an off-diagonal transition, attributed to loss of the antibonding electron from FeH-, to yield a low-spin quartet ground state of FeH. A diagonal transition results in an FeH state at 1945±55 cm-1; this state of FeH is assigned as the lowest-lying high-spin sextet state of FeH. An additional excited state of MnH and two other excited states of FeH are observed. Excitation energies for all the states are reported; vibrational frequencies and bond lengths for the ions and several states of the neutrals are also determined from the spectra. The electron affinity of MnH is found to be 0.869±0.010 eV; and the electron affinity of FeH is determined to be 0.934±0.011 eV. Spectroscopic constants for the various deuterides are also reported.

Theory of Nonlinear Dispersive Waves and Selection of the Ground State

International Nuclear Information System (INIS)

Soffer, A.; Weinstein, M.I.

2005-01-01

A theory of time-dependent nonlinear dispersive equations of the Schroedinger or Gross-Pitaevskii and Hartree type is developed. The short, intermediate and large time behavior is found, by deriving nonlinear master equations (NLME), governing the evolution of the mode powers, and by a novel multitime scale analysis of these equations. The scattering theory is developed and coherent resonance phenomena and associated lifetimes are derived. Applications include Bose-Einstein condensate large time dynamics and nonlinear optical systems. The theory reveals a nonlinear transition phenomenon, 'selection of the ground state', and NLME predicts the decay of excited state, with half its energy transferred to the ground state and half to radiation modes. Our results predict the recent experimental observations of Mandelik et al. in nonlinear optical waveguides

Ground-state properties of third-row elements with nonlocal density functionals

International Nuclear Information System (INIS)

Bagno, P.; Jepsen, O.; Gunnarsson, O.

1989-01-01

The cohesive energy, the lattice parameter, and the bulk modulus of third-row elements are calculated using the Langreth-Mehl-Hu (LMH), the Perdew-Wang (PW), and the gradient expansion functionals. The PW functional is found to give somewhat better results than the LMH functional and both are found to typically remove half the errors in the local-spin-density (LSD) approximation, while the gradient expansion gives worse results than the local-density approximation. For Fe both the LMH and PW functionals correctly predict a ferromagnetic bcc ground state, while the LSD approximation and the gradient expansion predict a nonmagnetic fcc ground state

Ground-state configuration of neutron-rich Aluminum isotopes through Coulomb Breakup

Directory of Open Access Journals (Sweden)

Chakraborty S.

2014-03-01

Full Text Available Neutron-rich 34,35Al isotopes have been studied through Coulomb excitation using LAND-FRS setup at GSI, Darmstadt. The method of invariant mass analysis has been used to reconstruct the excitation energy of the nucleus prior to decay. Comparison of experimental CD cross-section with direct breakup model calculation with neutron in p3/2 orbital favours 34Al(g.s⊗νp3/2 as ground state configuration of 35Al. But ground state configuration of 34Al is complicated as evident from γ-ray spectra of 33Al after Coulomb breakup of 34Al.

Coherence and entanglement in the ground state of a bosonic Josephson junction: From macroscopic Schroedinger cat states to separable Fock states

International Nuclear Information System (INIS)

Mazzarella, G.; Toigo, F.; Salasnich, L.; Parola, A.

2011-01-01

We consider a bosonic Josephson junction made of N ultracold and dilute atoms confined by a quasi-one-dimensional double-well potential within the two-site Bose-Hubbard model framework. The behavior of the system is investigated at zero temperature by varying the interatomic interaction from the strongly attractive regime to the repulsive one. We show that the ground state exhibits a crossover from a macroscopic Schroedinger-cat state to a separable Fock state through an atomic coherent regime. By diagonalizing the Bose-Hubbard Hamiltonian we characterize the emergence of the macroscopic cat states by calculating the Fisher information F, the coherence by means of the visibility α of the interference fringes in the momentum distribution, and the quantum correlations by using the entanglement entropy S. Both Fisher information and visibility are shown to be related to the ground-state energy by employing the Hellmann-Feynman theorem. This result, together with a perturbative calculation of the ground-state energy, allows simple analytical formulas for F and α to be obtained over a range of interactions, in excellent agreement with the exact diagonalization of the Bose-Hubbard Hamiltonian. In the attractive regime the entanglement entropy attains values very close to its upper limit for a specific interaction strength lying in the region where coherence is lost and self-trapping sets in.

Guidelines for earthquake ground motion definition for the Eastern United States

International Nuclear Information System (INIS)

Gwaltney, R.C.; Aramayo, G.A.; Williams, R.T.

1985-01-01

Guidelines for the determination of earthquake ground-motion definition for the eastern United States are established in this paper. Both far-field and near-field guidelines are given. The guidelines were based on an extensive review of the current procedures for specifying ground motion in the United States. Both empirical and theoretical procedures were used in establishing the guidelines because of the low seismicity in the eastern United States. Only a few large to great (M > 7.5) sized earthquakes have occurred in this region, no evidence of tectonic surface ruptures related to historic or Holocene earthquakes have been found, and no currently active plate boundaries of any kind are known in this region. Very little instrumented data has been gathered in the East. Theoretical procedures are proposed so that in regions of almost no data a reasonable level of seismic ground motion activity can be assumed. The guidelines are to be used to develop the Safe Shutdown Earthquake, SSE. A new procedure for establishing the Operating Basis Earthquake, OBE, is proposed, in particular for the eastern United States. The OBE would be developed using a probabilistic assessment of the geological conditions and the recurrence of seismic events at a site. These guidelines should be useful in development of seismic design requirements for future reactors

"Emergence" vs. "Forcing" of Empirical Data? A Crucial Problem of "Grounded Theory" Reconsidered

Directory of Open Access Journals (Sweden)

Udo Kelle

2005-05-01

Full Text Available Since the late 1960s Barney GLASER and Anselm STRAUSS, developers of the methodology of "Grounded Theory" have made several attempts to explicate, clarify and reconceptualise some of the basic tenets of their methodological approach. Diverging concepts and understandings of Grounded Theory have arisen from these attempts which have led to a split between its founders. Much of the explication and reworking of Grounded Theory surrounds the relation between data and theory and the role of previous theoretical assumptions. The book which initially established the popularity of GLASER's and STRAUSS' methodological ideas, "The Discovery of Grounded Theory", contains two conflicting understandings of the relation between data and theory—the concept of "emergence" on the one hand and the concept of "theoretical sensitivity" on the other hand. Much of the later developments of Grounded Theory can be seen as attempts to reconcile these prima facie diverging concepts. Thereby GLASER recommends to draw on a variety of "coding families" while STRAUSS proposes the use of a general theory of action to build an axis for an emerging theory. This paper first summarises the most important developments within "Grounded Theory" concerning the understanding of the relation between empirical data and theoretical statements. Thereby special emphasis will be laid on differences between GLASER's and STRAUSS' concepts and on GLASER's current critique that the concepts of "coding paradigm" and "axial coding" described by STRAUSS and Juliet CORBIN lead to the "forcing" of data. It will be argued that GLASER's critique points out some existing weaknesses of STRAUSS' concepts but vastly exaggerates the risks of the STRAUSSian approach. A main argument of this paper is that basic problems of empirically grounded theory construction can be treated much more effectively if one draws on certain results of contemporary philosophical and epistemological discussions and on widely

Quadriceps force and anterior tibial force occur obviously later than vertical ground reaction force: a simulation study

OpenAIRE

Ueno, Ryo; Ishida, Tomoya; Yamanaka, Masanori; Taniguchi, Shohei; Ikuta, Ryohei; Samukawa, Mina; Saito, Hiroshi; Tohyama, Harukazu

2017-01-01

Background: Although it is well known that quadriceps force generates anterior tibial force, it has been unclear whether quadriceps force causes great anterior tibial force during the early phase of a landing task. The purpose of the present study was to examine whether the quadriceps force induced great anterior tibial force during the early phase of a landing task. Methods: Fourteen young, healthy, female subjects performed a single-leg landing task. Muscle force and anterior tibial force w...

Quantum double-well chain: Ground-state phases and applications to hydrogen-bonded materials

International Nuclear Information System (INIS)

Wang, X.; Campbell, D.K.; Gubernatis, J.E.

1994-01-01

Extrapolating the results of hybrid quantum Monte Carlo simulations to the zero temperature and infinite-chain-length limits, we calculate the ground-state phase diagram of a system of quantum particles on a chain of harmonically coupled, symmetric, quartic double-well potentials. We show that the ground state of this quantum chain depends on two parameters, formed from the ratios of the three natural energy scales in the problem. As a function of these two parameters, the quantum ground state can exhibit either broken symmetry, in which the expectation values of the particle's coordinate are all nonzero (as would be the case for a classical chain), or restored symmetry, in which the expectation values of the particle's coordinate are all zero (as would be the case for a single quantum particle). In addition to the phase diagram as a function of these two parameters, we calculate the ground-state energy, an order parameter related to the average position of the particle, and the susceptibility associated with this order parameter. Further, we present an approximate analytic estimate of the phase diagram and discuss possible physical applications of our results, emphasizing the behavior of hydrogen halides under pressure

Probabilistic low-rank factorization accelerates tensor network simulations of critical quantum many-body ground states

Science.gov (United States)

Kohn, Lucas; Tschirsich, Ferdinand; Keck, Maximilian; Plenio, Martin B.; Tamascelli, Dario; Montangero, Simone

2018-01-01

We provide evidence that randomized low-rank factorization is a powerful tool for the determination of the ground-state properties of low-dimensional lattice Hamiltonians through tensor network techniques. In particular, we show that randomized matrix factorization outperforms truncated singular value decomposition based on state-of-the-art deterministic routines in time-evolving block decimation (TEBD)- and density matrix renormalization group (DMRG)-style simulations, even when the system under study gets close to a phase transition: We report linear speedups in the bond or local dimension of up to 24 times in quasi-two-dimensional cylindrical systems.

Force Transmission Modes of Non-Cohesive and Cohesive Materials at the Critical State.

Science.gov (United States)

Wang, Ji-Peng

2017-08-31

This paper investigates the force transmission modes, mainly described by probability density distributions, in non-cohesive dry and cohesive wet granular materials by discrete element modeling. The critical state force transmission patterns are focused on with the contact model effect being analyzed. By shearing relatively dense and loose dry specimens to the critical state in the conventional triaxial loading path, it is observed that there is a unique critical state force transmission mode. There is a universe critical state force distribution pattern for both the normal contact forces and tangential contact forces. Furthermore, it is found that using either the linear Hooke or the non-linear Hertz model does not affect the universe force transmission mode, and it is only related to the grain size distribution. Wet granular materials are also simulated by incorporating a water bridge model. Dense and loose wet granular materials are tested, and the critical state behavior for the wet material is also observed. The critical state strength and void ratio of wet granular materials are higher than those of a non-cohesive material. The critical state inter-particle distribution is altered from that of a non-cohesive material with higher probability in relatively weak forces. Grains in non-cohesive materials are under compressive stresses, and their principal directions are mainly in the axial loading direction. However, for cohesive wet granular materials, some particles are in tension, and the tensile stresses are in the horizontal direction on which the confinement is applied. The additional confinement by the tensile stress explains the macro strength and dilatancy increase in wet samples.

Development of a Subject-Specific Foot-Ground Contact Model for Walking.

Science.gov (United States)

Jackson, Jennifer N; Hass, Chris J; Fregly, Benjamin J

2016-09-01

Computational walking simulations could facilitate the development of improved treatments for clinical conditions affecting walking ability. Since an effective treatment is likely to change a patient's foot-ground contact pattern and timing, such simulations should ideally utilize deformable foot-ground contact models tailored to the patient's foot anatomy and footwear. However, no study has reported a deformable modeling approach that can reproduce all six ground reaction quantities (expressed as three reaction force components, two center of pressure (CoP) coordinates, and a free reaction moment) for an individual subject during walking. This study proposes such an approach for use in predictive optimizations of walking. To minimize complexity, we modeled each foot as two rigid segments-a hindfoot (HF) segment and a forefoot (FF) segment-connected by a pin joint representing the toes flexion-extension axis. Ground reaction forces (GRFs) and moments acting on each segment were generated by a grid of linear springs with nonlinear damping and Coulomb friction spread across the bottom of each segment. The stiffness and damping of each spring and common friction parameter values for all springs were calibrated for both feet simultaneously via a novel three-stage optimization process that used motion capture and ground reaction data collected from a single walking trial. The sequential three-stage process involved matching (1) the vertical force component, (2) all three force components, and finally (3) all six ground reaction quantities. The calibrated model was tested using four additional walking trials excluded from calibration. With only small changes in input kinematics, the calibrated model reproduced all six ground reaction quantities closely (root mean square (RMS) errors less than 13 N for all three forces, 25 mm for anterior-posterior (AP) CoP, 8 mm for medial-lateral (ML) CoP, and 2 N·m for the free moment) for both feet in all walking trials. The

Electromagnetically induced transparency and absorption due to optical and ground-state coherences in 6Li

International Nuclear Information System (INIS)

Fuchs, J; Duffy, G J; Rowlands, W J; Lezama, A; Hannaford, P; Akulshin, A M

2007-01-01

We present an experimental study of sub-natural width resonances in fluorescence from a collimated beam of 6 Li atoms excited on the D 1 and D 2 lines by a bichromatic laser field. We show that in addition to ground-state Zeeman coherence, coherent population oscillations between ground and excited states contribute to the sub-natural resonances. High-contrast resonances of electromagnetically induced transparency and electromagnetically induced absorption due to both effects, i.e., ground-state Zeeman coherence and coherent population oscillations, are observed

Solid-State Laser Research Report: Energy Transfer in Non-Uniform Codoped Crystals.

Science.gov (United States)

1988-03-01

mathematical steps reported in this document are contained in the reviewed classified mid-task report P-1970 which is not available to the open...splits the d lvels of the chromium ion such that the "T2 level is considerably higher in energy than the E level. Since the ground-state is A 2 , the E A 2

Study of ground state optical transfer for ultracold alkali dimers

Science.gov (United States)

Bouloufa-Maafa, Nadia; Londono, Beatriz; Borsalino, Dimitri; Vexiau, Romain; Mahecha, Jorge; Dulieu, Olivier; Luc-Koenig, Eliane

2013-05-01

Control of molecular states by laser pulses offer promising potential applications. The manipulation of molecules by external fields requires precise knowledge of the molecular structure. Our motivation is to perform a detailed analysis of the spectroscopic properties of alkali dimers, with the aim to determine efficient optical paths to form molecules in the absolute ground state and to determine the optimal parameters of the optical lattices where those molecules are manipulated to avoid losses by collisions. To this end, we use state of the art molecular potentials, R-dependent spin-orbit coupling and transition dipole moment to perform our calculations. R-dependent SO coupling are of crucial importance because the transitions occur at internuclear distances where they are affected by this R-dependence. Efficient schemes to transfer RbCs, KRb and KCs to the absolute ground state as well as the optimal parameters of the optical lattices will be presented. This work was supported in part by ``Triangle de la Physique'' under contract 2008-007T-QCCM (Quantum Control of Cold Molecules).

Ground State of Bosons in Bose-Fermi Mixture with Spin-Orbit Coupling

Science.gov (United States)

Sakamoto, Ryohei; Ono, Yosuke; Hatsuda, Rei; Shiina, Kenta; Arahata, Emiko; Mori, Hiroyuki

2017-07-01

We study an effect of spin-1/2 fermions on the ground state of a Bose system with equal Rashba and Dresselhaus spin-orbit coupling. By using mean-field and tight-binding approximations, we show the ground state phase diagram of the Bose system in the spin-orbit coupled Bose-Fermi mixture and find that the characteristic phase domain, where a spin current of fermions may be induced, can exist even in the presence of a significantly large number of fermions.

Estimation of ground reaction forces and joint moments on the basis on plantar pressure insoles and wearable sensors for joint angle measurement.

Science.gov (United States)

Ostaszewski, Michal; Pauk, Jolanta

2018-05-16

Gait analysis is a useful tool medical staff use to support clinical decision making. There is still an urgent need to develop low-cost and unobtrusive mobile health monitoring systems. The goal of this study was twofold. Firstly, a wearable sensor system composed of plantar pressure insoles and wearable sensors for joint angle measurement was developed. Secondly, the accuracy of the system in the measurement of ground reaction forces and joint moments was examined. The measurements included joint angles and plantar pressure distribution. To validate the wearable sensor system and examine the effectiveness of the proposed method for gait analysis, an experimental study on ten volunteer subjects was conducted. The accuracy of measurement of ground reaction forces and joint moments was validated against the results obtained from a reference motion capture system. Ground reaction forces and joint moments measured by the wearable sensor system showed a root mean square error of 1% for min. GRF and 27.3% for knee extension moment. The correlation coefficient was over 0.9, in comparison with the stationary motion capture system. The study suggests that the wearable sensor system could be recommended both for research and clinical applications outside a typical gait laboratory.

Sideband cooling of micromechanical motion to the quantum ground state.

Science.gov (United States)

Teufel, J D; Donner, T; Li, Dale; Harlow, J W; Allman, M S; Cicak, K; Sirois, A J; Whittaker, J D; Lehnert, K W; Simmonds, R W

2011-07-06

The advent of laser cooling techniques revolutionized the study of many atomic-scale systems, fuelling progress towards quantum computing with trapped ions and generating new states of matter with Bose-Einstein condensates. Analogous cooling techniques can provide a general and flexible method of preparing macroscopic objects in their motional ground state. Cavity optomechanical or electromechanical systems achieve sideband cooling through the strong interaction between light and motion. However, entering the quantum regime--in which a system has less than a single quantum of motion--has been difficult because sideband cooling has not sufficiently overwhelmed the coupling of low-frequency mechanical systems to their hot environments. Here we demonstrate sideband cooling of an approximately 10-MHz micromechanical oscillator to the quantum ground state. This achievement required a large electromechanical interaction, which was obtained by embedding a micromechanical membrane into a superconducting microwave resonant circuit. To verify the cooling of the membrane motion to a phonon occupation of 0.34 ± 0.05 phonons, we perform a near-Heisenberg-limited position measurement within (5.1 ± 0.4)h/2π, where h is Planck's constant. Furthermore, our device exhibits strong coupling, allowing coherent exchange of microwave photons and mechanical phonons. Simultaneously achieving strong coupling, ground state preparation and efficient measurement sets the stage for rapid advances in the control and detection of non-classical states of motion, possibly even testing quantum theory itself in the unexplored region of larger size and mass. Because mechanical oscillators can couple to light of any frequency, they could also serve as a unique intermediary for transferring quantum information between microwave and optical domains.

Ground-state kinetics of bistable redox-active donor-acceptor mechanically interlocked molecules.

Science.gov (United States)

Fahrenbach, Albert C; Bruns, Carson J; Li, Hao; Trabolsi, Ali; Coskun, Ali; Stoddart, J Fraser

2014-02-18

The ability to design and confer control over the kinetics of theprocesses involved in the mechanisms of artificial molecular machines is at the heart of the challenge to create ones that can carry out useful work on their environment, just as Nature is wont to do. As one of the more promising forerunners of prototypical artificial molecular machines, chemists have developed bistable redox-active donor-acceptor mechanically interlocked molecules (MIMs) over the past couple of decades. These bistable MIMs generally come in the form of [2]rotaxanes, molecular compounds that constitute a ring mechanically interlocked around a dumbbell-shaped component, or [2]catenanes, which are composed of two mechanically interlocked rings. As a result of their interlocked nature, bistable MIMs possess the inherent propensity to express controllable intramolecular, large-amplitude, and reversible motions in response to redox stimuli. In this Account, we rationalize the kinetic behavior in the ground state for a large assortment of these types of bistable MIMs, including both rotaxanes and catenanes. These structures have proven useful in a variety of applications ranging from drug delivery to molecular electronic devices. These bistable donor-acceptor MIMs can switch between two different isomeric states. The favored isomer, known as the ground-state co-conformation (GSCC) is in equilibrium with the less favored metastable state co-conformation (MSCC). The forward (kf) and backward (kb) rate constants associated with this ground-state equilibrium are intimately connected to each other through the ground-state distribution constant, KGS. Knowing the rate constants that govern the kinetics and bring about the equilibration between the MSCC and GSCC, allows researchers to understand the operation of these bistable MIMs in a device setting and apply them toward the construction of artificial molecular machines. The three biggest influences on the ground-state rate constants arise from

Adsorbing polymers subject to an elongational force: the effect of pulling direction

Energy Technology Data Exchange (ETDEWEB)

Orlandini, E [Dipartimento di Fisica, CNISM, Universita di Padova, Via Marzolo 8, 35131 Padova (Italy); Whittington, S G, E-mail: enzo.orlandini@pd.infn.i [Department of Chemistry, University of Toronto, Toronto (Canada)

2010-12-03

We investigate partially directed walk models of polymers adsorbed at a surface under the influence of an applied force. The force can be applied at various angles (from perpendicular to parallel to the surface) and the critical force-temperature curves are strongly angle-dependent. We observe some interesting differences between the two- and three-dimensional cases associated with the degeneracy of the ground state in three dimensions.

Source evaluation report phase 2 investigation: Limited field investigation. Final report: United States Air Force Environmental Restoration Program, Eielson Air Force Base, Alaska

Energy Technology Data Exchange (ETDEWEB)

1994-10-01

This report describes the limited field investigation work done to address issues and answer unresolved questions regarding a collection of potential contaminant sources at Eielson Air Force Base (AFB), near Fairbanks, Alaska. These sources were listed in the Eielson AFB Federal Facility Agreement supporting the Comprehensive Environmental Response, Compensation, and Liability Act (CERCLA) cleanup of the base. The limited field investigation began in 1993 to resolve all remaining technical issues and provide the data and analysis required to evaluate the environmental hazard associated with these sites. The objective of the limited field investigation was to allow the remedial project managers to sort each site into one of three categories: requiring remedial investigation/feasibility study, requiring interim removal action, or requiring no further remedial action.

State income tax policy and geographic labour force mobility in the United States.

Science.gov (United States)

Saltz, I S

1998-10-01

"This study empirically investigates the impact of state income tax policy on U.S. interstate migration [of the labor force] for the period 1985-89. It finds that people vote with their feet and prefer to move so as to minimize their state income tax liabilities." excerpt

Symmetry Breakdown in Ground State Dissociation of HD+

International Nuclear Information System (INIS)

Ben-Itzhak, I.; Wells, E.; Carnes, K. D.; Krishnamurthi, Vidhya; Weaver, O. L.; Esry, B. D.

2000-01-01

Experimental studies of the dissociation of the electronic ground state of HD + following ionization of HD by fast proton impact indicate that the H + +D 1s dissociation channel is more likely than the H1s+D + dissociation channel by about 7% . This isotopic symmetry breakdown is due to the finite nuclear mass correction to the Born-Oppenheimer approximation which makes the 1sσ state 3.7 meV lower than the 2pσ state at the dissociation limit. The measured fractions of the two dissociation channels are in agreement with coupled-channels calculations of 1sσ to 2pσ transitions. (c) 2000 The American Physical Society

Non-Gaussian ground-state deformations near a black-hole singularity

Science.gov (United States)

Hofmann, Stefan; Schneider, Marc

2017-03-01

The singularity theorem by Hawking and Penrose qualifies Schwarzschild black holes as geodesic incomplete space-times. Albeit this is a mathematically rigorous statement, it requires an operational framework that allows us to probe the spacelike singularity via a measurement process. Any such framework necessarily has to be based on quantum theory. As a consequence, the notion of classical completeness needs to be adapted to situations where the only adequate description is in terms of quantum fields in dynamical space-times. It is shown that Schwarzschild black holes turn out to be complete when probed by self-interacting quantum fields in the ground state and in excited states. The measure for populating quantum fields on hypersurfaces in the vicinity of the black-hole singularity goes to zero towards the singularity. This statement is robust under non-Gaussian deformations of and excitations relative to the ground state. The physical relevance of different completeness concepts for black holes is discussed.

Traces of Lorentz symmetry breaking in a hydrogen atom at ground state

Science.gov (United States)

Borges, L. H. C.; Barone, F. A.

2016-02-01

Some traces of a specific Lorentz symmetry breaking scenario in the ground state of the hydrogen atom are investigated. We use standard Rayleigh-Schrödinger perturbation theory in order to obtain the corrections to the ground state energy and the wave function. It is shown that an induced four-pole moment arises, due to the Lorentz symmetry breaking. The model considered is the one studied in Borges et al. (Eur Phys J C 74:2937, 2014), where the Lorentz symmetry is broken in the electromagnetic sector.

Traces of Lorentz symmetry breaking in a hydrogen atom at ground state

Energy Technology Data Exchange (ETDEWEB)

Borges, L.H.C. [Universidade Federal do ABC, Centro de Ciencias Naturais e Humanas, Santo Andre, SP (Brazil); Barone, F.A. [IFQ-Universidade Federal de Itajuba, Itajuba, MG (Brazil)

2016-02-15

Some traces of a specific Lorentz symmetry breaking scenario in the ground state of the hydrogen atom are investigated. We use standard Rayleigh-Schroedinger perturbation theory in order to obtain the corrections to the ground state energy and the wave function. It is shown that an induced four-pole moment arises, due to the Lorentz symmetry breaking. The model considered is the one studied in Borges et al. (Eur Phys J C 74:2937, 2014), where the Lorentz symmetry is broken in the electromagnetic sector. (orig.)

Traces of Lorentz symmetry breaking in a hydrogen atom at ground state

International Nuclear Information System (INIS)

Borges, L.H.C.; Barone, F.A.

2016-01-01

Some traces of a specific Lorentz symmetry breaking scenario in the ground state of the hydrogen atom are investigated. We use standard Rayleigh-Schroedinger perturbation theory in order to obtain the corrections to the ground state energy and the wave function. It is shown that an induced four-pole moment arises, due to the Lorentz symmetry breaking. The model considered is the one studied in Borges et al. (Eur Phys J C 74:2937, 2014), where the Lorentz symmetry is broken in the electromagnetic sector. (orig.)

Spin-polarized ground state and exact quantization at ν=5/2

Science.gov (United States)

Pan, Wei

2002-03-01

The nature of the even-denominator fractional quantum Hall effect at ν=5/2 remains elusive, in particular, its ground state spin-polarization. An earlier, so-called "hollow core" model arrived at a spin-unpolarized wave function. The more recent calculations based on a model of BCS-like pairing of composite fermions, however, suggest that its ground state is spin-polarized. In this talk, I will first review the earlier experiments and then present our recent experimental results showing evidence for a spin-polarized state at ν=5/2. Our ultra-low temperature experiments on a high quality sample established the fully developed FQHE state at ν=5/2 as well as at ν=7/3 and 8/3, manifested by a vanishing R_xx and exact quantization of the Hall plateau. The tilted field experiments showed that the added in-plane magnetic fields not only destroyed the FQHE at ν=5/2, as seen before, but also induced an electrical anisotropy, which is now interpreted as a phase transition from a paired, spin-polarized ν=5/2 state to a stripe phase, not unlike the ones at ν=9/2, 11/2, etc in the N > 1 higher Landau levels. Furthermore, in the experiments on the heterojunction insulated-gate field-effect transistors (HIGFET) at dilution refrigerator temperatures, a strong R_xx minimum and a concomitant developing Hall plateau were observed at ν=5/2 in a magnetic field as high as 12.6 Tesla. This and the subsequent density dependent studies of its energy gap largely rule out a spin-singlet state and point quite convincingly towards a spin-polarized ground state at ν=5/2.

Basic Pay In The United States All-Volunteer Armed Forces

National Research Council Canada - National Science Library

Carson, Kenneth

2000-01-01

As the United States enters the 21st century, the readiness of its over 1.4 million all-volunteer armed forces is as important today as anytime during the 27 year history of the modern all-volunteer force (AVF...

Probing a gravitational cat state

International Nuclear Information System (INIS)

Anastopoulos, C; Hu, B L

2015-01-01

We investigate the nature of a gravitational two-state system (G2S) in the simplest setup in Newtonian gravity. In a quantum description of matter a single motionless massive particle can in principle be in a superposition state of two spatially separated locations. This superposition state in gravity, or gravitational cat state, would lead to fluctuations in the Newtonian force exerted on a nearby test particle. The central quantity of importance for this inquiry is the energy density correlation. This corresponds to the noise kernel in stochastic gravity theory, evaluated in the weak field nonrelativistic limit. In this limit quantum fluctuations of the stress–energy tensor manifest as the fluctuations of the Newtonian force. We describe the properties of such a G2S system and present two ways of measuring the cat state for the Newtonian force, one by way of a classical probe, the other a quantum harmonic oscillator. Our findings include: (i) mass density fluctuations persist even in single particle systems, and they are of the same order of magnitude as the mean; (ii) a classical probe generically records a non-Markovian fluctuating force; (iii) a quantum probe interacting with the G2S system may undergo Rabi oscillations in a strong coupling regime. This simple prototypical gravitational quantum system could provide a robust testing ground to compare predictions from alternative quantum theories, since the results reported here are based on standard quantum mechanics and classical gravity. (paper)

On the topological ground state of E-infinity spacetime and the super string connection

International Nuclear Information System (INIS)

El Naschie, M.S.

2007-01-01

There are at present a huge number of valid super string ground states, making the one corresponding to our own universe extremely hard to determine. Therefore it may come as quite a surprise that it is a rather simple undertaking to determine the exact topological ground state of E-infinity Cantorian spacetime theory. Similar to the ground state of the Higgs for E-infinity, the expectation value of the topological ground state is non-zero and negative. Its value is given exactly by -bar o -∼ n(1/φ) n =-(4+φ 3 ) where φ=(5-1)/2 and n represents an integer Menger-Uhryson dimension running from n=0 to n=-∼. Recalling that the average dimension of ε (∼) is given by ∼ =4+φ 3 , one could interpret this result as saying that our E-infinity spacetime may be viewed as an in itself closed manifold given by the remarkable equation: + =zeroThus in a manner of speaking, the universe could have spontaneously tunnelled into existence from virtual nothingness

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; 68.5 years and 69.0 years 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. Copyright © 2015 Elsevier B.V. All rights reserved.

Functional data analysis on ground reaction force of military load carriage increment

Science.gov (United States)

Din, Wan Rozita Wan; Rambely, Azmin Sham

2014-06-01

Analysis of ground reaction force on military load carriage is done through functional data analysis (FDA) statistical technique. The main objective of the research is to investigate the effect of 10% load increment and to find the maximum suitable load for the Malaysian military. Ten military soldiers age 31 ± 6.2 years, weigh 71.6 ± 10.4 kg and height of 166.3 ± 5.9 cm carrying different military load range from 0% body weight (BW) up to 40% BW participated in an experiment to gather the GRF and kinematic data using Vicon Motion Analysis System, Kirstler force plates and thirty nine body markers. The analysis is conducted in sagittal, medial lateral and anterior posterior planes. The results show that 10% BW load increment has an effect when heel strike and toe-off for all the three planes analyzed with P-value less than 0.001 at 0.05 significant levels. FDA proves to be one of the best statistical techniques in analyzing the functional data. It has the ability to handle filtering, smoothing and curve aligning according to curve features and points of interest.

Space station operations task force. Panel 4 report: Management integration

Science.gov (United States)

1987-01-01

The Management Integration Panel of the Space Station Operations Task Force was chartered to provide a structure and ground rules for integrating the efforts of the other three panels and to address a number of cross cutting issues that affect all areas of space station operations. Issues addressed include operations concept implementation, alternatives development and integration process, strategic policy issues and options, and program management emphasis areas.

Ground-state electronic structure of actinide monocarbides and mononitrides

DEFF Research Database (Denmark)

Petit, Leon; Svane, Axel; Szotek, Z.

2009-01-01

The self-interaction corrected local spin-density approximation is used to investigate the ground-state valency configuration of the actinide ions in the actinide monocarbides, AC (A=U,Np,Pu,Am,Cm), and the actinide mononitrides, AN. The electronic structure is characterized by a gradually increa...

Guidelines for earthquake ground motion definition for the eastern United States

International Nuclear Information System (INIS)

Gwaltney, R.C.; Aramayo, G.A.; Williams, R.T.

1985-01-01

Guidelines for the determination of earthquake ground-motion definition for the eastern United States are established in this paper. Both far-field and near-field guidelines are given. The guidelines were based on an extensive review of the current procedures for specifying ground motion in the United States. Both empirical and theoretical procedures were used in establishing the guidelines because of the low seismicity in the eastern United States. Only a few large to great (M > 7.5) sized earthquakes have occurred in this region, no evidence of tectonic surface ruptures related to historic or Holocene earthquakes have been found, and no currently active plate boundaries of any kind are known in this region. Very little instrumented data has been gathered in the East. Theoretical procedures are proposed so that in regions of almost no data a reasonable level of seismic ground motion activity can be assumed. The guidelines are to be used to develop the Safe Shutdown Earthquake, SSE. A new procedure for establishing the Operating Basis Earthquake, OBE, is proposed, in particular for the eastern United States. The OBE would be developed using a probabilistic assessment of the geological conditions and the recurrence of seismic events at a site. These guidelines should be useful in development of seismic design requirements for future reactors. 17 refs., 2 figs., 1 tab

Quantifying confidence in density functional theory predictions of magnetic ground states

Science.gov (United States)

Houchins, Gregory; Viswanathan, Venkatasubramanian

2017-10-01

Density functional theory (DFT) simulations, at the generalized gradient approximation (GGA) level, are being routinely used for material discovery based on high-throughput descriptor-based searches. The success of descriptor-based material design relies on eliminating bad candidates and keeping good candidates for further investigation. While DFT has been widely successfully for the former, oftentimes good candidates are lost due to the uncertainty associated with the DFT-predicted material properties. Uncertainty associated with DFT predictions has gained prominence and has led to the development of exchange correlation functionals that have built-in error estimation capability. In this work, we demonstrate the use of built-in error estimation capabilities within the BEEF-vdW exchange correlation functional for quantifying the uncertainty associated with the magnetic ground state of solids. We demonstrate this approach by calculating the uncertainty estimate for the energy difference between the different magnetic states of solids and compare them against a range of GGA exchange correlation functionals as is done in many first-principles calculations of materials. We show that this estimate reasonably bounds the range of values obtained with the different GGA functionals. The estimate is determined as a postprocessing step and thus provides a computationally robust and systematic approach to estimating uncertainty associated with predictions of magnetic ground states. We define a confidence value (c-value) that incorporates all calculated magnetic states in order to quantify the concurrence of the prediction at the GGA level and argue that predictions of magnetic ground states from GGA level DFT is incomplete without an accompanying c-value. We demonstrate the utility of this method using a case study of Li-ion and Na-ion cathode materials and the c-value metric correctly identifies that GGA-level DFT will have low predictability for NaFePO4F . Further, there

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.

Creating Space Plasma from the Ground

Science.gov (United States)

2016-05-12

AFRL-AFOSR-VA-TR-2016-0179 CREATING SPACE PLASMA FROM THE GROUND Herbert C Carlson UTAH STATE UNIVERSITY Final Report 05/12/2016 DISTRIBUTION A...DATE (DD-MM-YYYY) 05/14/2016 2. REPORT TYPE Final 3. DATES COVERED (From - To) 08/14/2012-05/14/2016 4. TITLE AND SUBTITLE Creating space plasma from...Report (2016) Creating Space Plasma from the Ground Grant FA9550-11-1-0236 AFOSR Program Manager Dr. Kent Miller PI: Herbert C. Carlson Center for

New ab initio adiabatic potential energy surfaces and bound state calculations for the singlet ground X˜ 1A1 and excited C˜ 1B2(21A') states of SO2

Science.gov (United States)

Kłos, Jacek; Alexander, Millard H.; Kumar, Praveen; Poirier, Bill; Jiang, Bin; Guo, Hua

2016-05-01

We report new and more accurate adiabatic potential energy surfaces (PESs) for the ground X˜ 1A1 and electronically excited C˜ 1B2(21A') states of the SO2 molecule. Ab initio points are calculated using the explicitly correlated internally contracted multi-reference configuration interaction (icMRCI-F12) method. A second less accurate PES for the ground X ˜ state is also calculated using an explicitly correlated single-reference coupled-cluster method with single, double, and non-iterative triple excitations [CCSD(T)-F12]. With these new three-dimensional PESs, we determine energies of the vibrational bound states and compare these values to existing literature data and experiment.

The ground-state phase diagrams of the spin-3/2 Ising model

International Nuclear Information System (INIS)

Canko, Osman; Keskin, Mustafa

2003-01-01

The ground-state spin configurations are obtained for the spin-3/2 Ising model Hamiltonian with bilinear and biquadratic exchange interactions and a single-ion crystal field. The interactions are assumed to be only between nearest-neighbors. The calculated ground-state phase diagrams are presented on diatomic lattices, such as the square, honeycomb and sc lattices, and triangular lattice in the (Δ/z vertical bar J vertical bar ,K/ vertical bar J vertical bar) and (H/z vertical bar J vertical bar, K/ vertical bar J vertical bar) planes

Fission barriers and asymmetric ground states in the relativistic mean-field theory

International Nuclear Information System (INIS)

Rutz, K.; Reinhard, P.G.; Greiner, W.

1995-01-01

The symmetric and asymmetric fission path for 240 Pu, 232 Th and 226 Ra is investigated within the relativistic mean-field model. Standard parametrizations which are well fitted to nuclear ground-state properties are found to deliver reasonable qualitative and quantitative features of fission, comparable to similar nonrelativistic calculations. Furthermore, stable octupole deformations in the ground states of radium isotopes are investigated. They are found in a series of isotopes, qualitatively in agreement with nonrelativistic models. But the quantitative details differ amongst the models and between the various relativistic parametrizations. (orig.)

Numerical study of ground state and low lying excitations of quantum antiferromagnets

International Nuclear Information System (INIS)

Trivedi, N.; Ceperley, D.M.

1989-01-01

The authors have studied, via Green function Monte Carlo (GFMC), the S = 1/2 Heisenberg quantum antiferromagnet in two dimensions on a square lattice. They obtain the ground state energy with only statistical errors E 0 /J = -0.6692(2), the staggered magnetization m † = 0.31(2), and from the long wave length behavior of the structure factor, the spin wave velocity c/c o = 1.14(5). They show that the ground state wave function has long range pair correlations arising from the zero point motion of spin waves

Optimized RVB states of the 2-d antiferromagnet: ground state and excitation spectrum

Science.gov (United States)

Chen, Yong-Cong; Xiu, Kai

1993-10-01

The Gutzwiller projection of the Schwinger-boson mean-field solution of the 2-d spin- {1}/{2} antiferromagnet in a square lattice is shown to produce the optimized, parameter-free RVB ground state. We get -0.6688 J/site and 0.311 for the energy and the staggered magnetization. The spectrum of the excited states is found to be linear and gapless near k≅0. Our calculation suggests, upon breaking of the rotational symmetry, ɛ k≅2JZ r1-γ 2k with Zr≅1.23.

Ground reaction forces and bone parameters in females with tibial stress fracture.

Science.gov (United States)

Bennell, Kim; Crossley, Kay; Jayarajan, Jyotsna; Walton, Elizabeth; Warden, Stuart; Kiss, Z Stephen; Wrigley, Tim

2004-03-01

Tibial stress fracture is a common overuse running injury that results from the interplay of repetitive mechanical loading and bone strength. This research project aimed to determine whether female runners with a history of tibial stress fracture (TSF) differ in ground reaction force (GRF) parameters during running, regional bone density, and tibial bone geometry from those who have never sustained a stress fracture (NSF). Thirty-six female running athletes (13 TSF; 23 NSF) ranging in age from 18 to 44 yr were recruited for this cross-sectional study. The groups were well matched for demographic, training, and menstrual parameters. A force platform measured selected GRF parameters (peak and time to peak for vertical impact and active forces, and horizontal braking and propulsive forces) during overground running at 4.0 m.s.(-1). Lumbar spine, proximal femur, and distal tibial bone mineral density were assessed by dual energy x-ray absorptiometry. Tibial bone geometry (cross-sectional dimensions and areas, and second moments of area) was calculated from a computerized tomography scan at the junction of the middle and distal thirds. There were no significant differences between the groups for any of the GRF, bone density, or tibial bone geometric parameters (P > 0.05). Both TSF and NSF subjects had bone density levels that were average or above average compared with a young adult reference range. Factor analysis followed by discriminant function analysis did not find any combinations of variables that differentiated between TSF and NSF groups. These findings do not support a role for GRF, bone density, or tibial bone geometry in the development of tibial stress fractures, suggesting that other risk factors were more important in this cohort of female runners.

Theoretical analysis of steady state operating forces in control valves

Directory of Open Access Journals (Sweden)

Basavaraj Hubballi

2018-01-01

Full Text Available The controlling components, such as valves are used to regulate controlled fluid power. It is not always possible to calculate valve forces accurately, and with some types of valves even the existence of certain types of forces cannot be predicted with certainty. In many cases, however, the analysis can be made fairly completely and accurately. The assumption of steady state conditions is valid for the valve alone, but transient effects in the rest of the system may be large. These effects are particularly important with regard to the instability of valves, where the system may react on the valve in such a way as to make it squeal or oscillate, sometimes with large amplitude. The origin of the steady state flow force understood from a brief qualitative explanation. The following paper will summarize much of what is known about valve forces in the spool type controlling element.

Ground-state energy for 1D (t,U,X)-model at low densities

International Nuclear Information System (INIS)

Buzatu, F.D.

1992-09-01

In describing the properties of quasi-1D materials with a highly-screened interelectronic potential, an attractive hopping term has to be added to the Hubbard Hamiltonian. The effective interaction and the ground-state energy in ladder approximation are analyzed. At low electronic densities, the attractive part of the interaction, initially smaller than the repulsive term, can become more effective, the ground-state energy decreasing below the unperturbed value. (author). 12 refs, 4 figs

Small RNA Sequencing Reveals Dlk1-Dio3 Locus-Embedded MicroRNAs as Major Drivers of Ground-State Pluripotency.

Science.gov (United States)

Moradi, Sharif; Sharifi-Zarchi, Ali; Ahmadi, Amirhossein; Mollamohammadi, Sepideh; Stubenvoll, Alexander; Günther, Stefan; Salekdeh, Ghasem Hosseini; Asgari, Sassan; Braun, Thomas; Baharvand, Hossein

2017-12-12

Ground-state pluripotency is a cell state in which pluripotency is established and maintained through efficient repression of endogenous differentiation pathways. Self-renewal and pluripotency of embryonic stem cells (ESCs) are influenced by ESC-associated microRNAs (miRNAs). Here, we provide a comprehensive assessment of the "miRNome" of ESCs cultured under conditions favoring ground-state pluripotency. We found that ground-state ESCs express a distinct set of miRNAs compared with ESCs grown in serum. Interestingly, most "ground-state miRNAs" are encoded by an imprinted region on chromosome 12 within the Dlk1-Dio3 locus. Functional analysis revealed that ground-state miRNAs embedded in the Dlk1-Dio3 locus (miR-541-5p, miR-410-3p, and miR-381-3p) promoted pluripotency via inhibition of multi-lineage differentiation and stimulation of self-renewal. Overall, our results demonstrate that ground-state pluripotency is associated with a unique miRNA signature, which supports ground-state self-renewal by suppressing differentiation. Copyright © 2017 The Authors. Published by Elsevier Inc. All rights reserved.

Task Force 1. Report of the Task Force on Patient Expectations, Core Values, Reintegration, and the New Model of Family Medicine

Science.gov (United States)

Green, Larry A.; Graham, Robert; Bagley, Bruce; Kilo, Charles M.; Spann, Stephen J.; Bogdewic, Stephen P.; Swanson, John

2004-01-01

BACKGROUND To lay the groundwork for the development of a comprehensive strategy to transform and renew the specialty of family medicine, this Future of Family Medicine task force was charged with identifying the core values of family medicine, developing proposals to reform family medicine to meet consumer expectations, and determining systems of care to be delivered by family medicine in the future. METHODS A diverse, multidisciplinary task force representing a broad spectrum of perspectives and expertise analyzed and discussed published literature; findings from surveys, interviews, and focus groups compiled by research firms contracted to the Future of Family Medicine project; and analyses from The Robert Graham Center, professional societies in the United States and abroad, and others. Through meetings, conference calls, and writing, and revision of a series of subcommittee reports, the entire task force reached consensus on its conclusions and recommendations. These were reviewed by an external panel of experts and revisions were made accordingly. MAJOR FINDINGS After delivering on its promise to reverse the decline of general practice in the United States, family medicine and the nation face additional challenges to assure all people receive care that is safe, effective, patient-centered, timely, efficient, and equitable. Challenges the discipline needs to address to improve family physicians’ ability to make important further contributions include developing a broader, more accurate understanding of the specialty among the public and other health professionals, addressing the wide scope and variance in practice types within family medicine, winning respect for the specialty in academic circles, making family medicine a more attractive career option, and dealing with the perception that family medicine is not solidly grounded in science and technology. The task force set forth a proposed identity statement for family medicine, a basket of services that

Electronic and ground state properties of ThTe

Energy Technology Data Exchange (ETDEWEB)

Bhardwaj, Purvee, E-mail: purveebhardwaj@gmail.com; Singh, Sadhna, E-mail: drsadhna100@gmail.com [High Pressure Research Lab. Department of Physics Barkatullah University, Bhopal (MP) 462026 (India)

2016-05-06

The electronic properties of ThTe in cesium chloride (CsCl, B2) structure are investigated in the present paper. To study the ground state properties of thorium chalcogenide, the first principle calculations have been calculated. The bulk properties, including lattice constant, bulk modulus and its pressure derivative are obtained. The calculated equilibrium structural parameters are in good agreement with the available experimental and theoretical results.

Evaluation of depleted uranium in the environment at Aberdeen Proving Grounds, Maryland and Yuma Proving Grounds, Arizona. Final report

International Nuclear Information System (INIS)

Kennedy, P.L.; Clements, W.H.; Myers, O.B.; Bestgen, H.T.; Jenkins, D.G.

1995-01-01

This report represents an evaluation of depleted uranium (DU) introduced into the environment at the Aberdeen Proving Grounds (APG), Maryland and Yuma Proving Grounds (YPG) Arizona. This was a cooperative project between the Environmental Sciences and Statistical Analyses Groups at LANL and with the Department of Fishery and Wildlife Biology at Colorado State University. The project represents a unique approach to assessing the environmental impact of DU in two dissimilar ecosystems. Ecological exposure models were created for each ecosystem and sensitivity/uncertainty analyses were conducted to identify exposure pathways which were most influential in the fate and transport of DU in the environment. Research included field sampling, field exposure experiment, and laboratory experiments. The first section addresses DU at the APG site. Chapter topics include bioenergetics-based food web model; field exposure experiments; bioconcentration by phytoplankton and the toxicity of U to zooplankton; physical processes governing the desorption of uranium from sediment to water; transfer of uranium from sediment to benthic invertebrates; spead of adsorpion by benthic invertebrates; uptake of uranium by fish. The final section of the report addresses DU at the YPG site. Chapters include the following information: Du transport processes and pathway model; field studies of performance of exposure model; uptake and elimination rates for kangaroo rates; chemical toxicity in kangaroo rat kidneys

Evaluation of depleted uranium in the environment at Aberdeen Proving Grounds, Maryland and Yuma Proving Grounds, Arizona. Final report

Energy Technology Data Exchange (ETDEWEB)

Kennedy, P.L.; Clements, W.H.; Myers, O.B.; Bestgen, H.T.; Jenkins, D.G. [Colorado State Univ., Fort Collins, CO (United States). Dept. of Fishery and Wildlife Biology

1995-01-01

This report represents an evaluation of depleted uranium (DU) introduced into the environment at the Aberdeen Proving Grounds (APG), Maryland and Yuma Proving Grounds (YPG) Arizona. This was a cooperative project between the Environmental Sciences and Statistical Analyses Groups at LANL and with the Department of Fishery and Wildlife Biology at Colorado State University. The project represents a unique approach to assessing the environmental impact of DU in two dissimilar ecosystems. Ecological exposure models were created for each ecosystem and sensitivity/uncertainty analyses were conducted to identify exposure pathways which were most influential in the fate and transport of DU in the environment. Research included field sampling, field exposure experiment, and laboratory experiments. The first section addresses DU at the APG site. Chapter topics include bioenergetics-based food web model; field exposure experiments; bioconcentration by phytoplankton and the toxicity of U to zooplankton; physical processes governing the desorption of uranium from sediment to water; transfer of uranium from sediment to benthic invertebrates; spead of adsorpion by benthic invertebrates; uptake of uranium by fish. The final section of the report addresses DU at the YPG site. Chapters include the following information: Du transport processes and pathway model; field studies of performance of exposure model; uptake and elimination rates for kangaroo rates; chemical toxicity in kangaroo rat kidneys.

Zero-Magnetic-Field Spin Splitting of Polaron's Ground State Energy Induced by Rashba Spin-Orbit Interaction

International Nuclear Information System (INIS)

Liu Jia; Xiao Jingling

2006-01-01

We study theoretically the ground state energy of a polaron near the interface of a polar-polar semiconductor by considering the Rashba spin-orbit (SO) coupling with the Lee-Low-Pines intermediate coupling method. Our numerical results show that the Rashba SO interaction originating from the inversion asymmetry in the heterostructure splits the ground state energy of the polaron. The electron areal density and vector dependence of the ratio of the SO interaction to the total ground state energy or other energy composition are obvious. One can see that even without any external magnetic field, the ground state energy can be split by the Rashba SO interaction, and this split is not a single but a complex one. Since the presents of the phonons, whose energy gives negative contribution to the polaron's, the spin-splitting states of the polaron are more stable than electron's.

Ground state energy and width of 7He from 8Li proton knockout

International Nuclear Information System (INIS)

Denby, D. H.; DeYoung, P. A.; Hall, C. C.; Baumann, T.; Bazin, D.; Spyrou, A.; Breitbach, E.; Howes, R.; Brown, J.; Frank, N.; Gade, A.; Mosby, S. M.; Peters, W. A.; Thoennessen, M.; Hinnefeld, J.; Hoffman, C. R.; Jenson, R. A.; Luther, B.; Olson, C. W.; Schiller, A.

2008-01-01

The ground state energy and width of 7 He has been measured with the Modular Neutron Array (MoNA) and superconducting dipole Sweeper magnet experimental setup at the National Superconducting Cyclotron Laboratory. 7 He was produced by proton knockout from a secondary 8 Li beam. The measured decay energy spectrum is compared to simulations based on Breit-Wigner line shape with an energy-dependent width for the resonant state. The energy of the ground state is found to be 400(10) keV with a full-width at half-maximum of 125( -15 +40 ) keV

Approximate photochemical dynamics of azobenzene with reactive force fields

Science.gov (United States)

Li, Yan; Hartke, Bernd

2013-12-01

We have fitted reactive force fields of the ReaxFF type to the ground and first excited electronic states of azobenzene, using global parameter optimization by genetic algorithms. Upon coupling with a simple energy-gap transition probability model, this setup allows for completely force-field-based simulations of photochemical cis→trans- and trans→cis-isomerizations of azobenzene, with qualitatively acceptable quantum yields. This paves the way towards large-scale dynamics simulations of molecular machines, including bond breaking and formation (via the reactive force field) as well as photochemical engines (presented in this work).

Towards the measurement of the ground-state hyperfine splitting of antihydrogen

Energy Technology Data Exchange (ETDEWEB)

Juhasz, Bertalan, E-mail: bertalan.juhasz@oeaw.ac.at [Austrian Academy of Sciences, Stefan Meyer Institute for Subatomic Physics (Austria)

2012-12-15

The ASACUSA collaboration at the Antiproton Decelerator of CERN is planning to measure the ground-state hyperfine splitting of antihydrogen using an atomic beam line, which will consist of a superconducting cusp trap as a source of partially polarized antihydrogen atoms, a radiofrequency spin-flip cavity, a superconducting sextupole magnet as spin analyser, and an antihydrogen detector. This will be a measurement of the antiproton magnetic moment, and also a test of the CPT invariance. Monte Carlo simulations predict that the antihydrogen ground-state hyperfine splitting can be determined with a relative precision of better than {approx} 10{sup - 6}. The first preliminary measurements of the hyperfine transitions will start in 2011.

State environmental reports of the Slovak Republic on Internet

International Nuclear Information System (INIS)

Kanianska, R.; Fabricius, A.; Marcinatova, L.

2005-01-01

The Slovak Environmental Agency under supervision of the Ministry of Environment of the Slovak Republic (SR) prepare yearly different types of reports with evaluation of state of environment of the Slovak Republic on the basis of verified statistical data which come from records of Statistical Office of the SR, Ministry of Environment of the SR, professional organisation of departments of environment, as well as from data bases of others central executive administration and their special organisations. Single report varies by form, content, structure and scope, for which were designed. They made available for public on the internet web-site http://www.enviroportal.sk/, eventually on the web-site of the Slovak Environmental Agency http://www.sazp.sk/. The following types of reports are published by the Slovak Environmental Agency: State of the Environment Reports of the Slovak Republic; State of the Environment Reports according to the D-P-S-I-R structure (where (Pressure - P, State - S, (Response - R, Driven forces - D, and Impact - I, indicators of the OECD); Report about impacts of economic sectors on the environment of the SR; Sustainable development indicators of the SR on national level. The form of presentation of individual indicators makes it possible to obtain information about present state, trends and fixing of these problems in strategic documents with possibility of their international comparison and access to relevant information on Internet

Exact ground state of finite Bose-Einstein condensates on a ring

International Nuclear Information System (INIS)

Sakmann, Kaspar; Streltsov, Alexej I.; Alon, Ofir E.; Cederbaum, Lorenz S.

2005-01-01

The exact ground state of the many-body Schroedinger equation for N bosons on a one-dimensional ring interacting via a pairwise δ-function interaction is presented for up to 50 particles. The solutions are obtained by solving Lieb and Liniger's system of coupled transcendental equations numerically for finite N. The ground-state energies for repulsive and attractive interactions are shown to be smoothly connected at the point of zero interaction strength, implying that the Bethe ansatz can be used also for attractive interactions for all cases studied. For repulsive interactions the exact energies are compared to (i) Lieb and Liniger's thermodynamic limit solution and (ii) the Tonks-Girardeau gas limit. It is found that the energy of the thermodynamic limit solution can differ substantially from that of the exact solution for finite N when the interaction is weak or when N is small. A simple relation between the Tonks-Girardeau gas limit and the solution for finite interaction strength is revealed. For attractive interactions we find that the true ground-state energy is given to a good approximation by the energy of the system of N attractive bosons on an infinite line, provided the interaction is stronger than the critical interaction strength of mean-field theory

Representing delayed force feedback as a combination of current and delayed states.

Science.gov (United States)

Avraham, Guy; Mawase, Firas; Karniel, Amir; Shmuelof, Lior; Donchin, Opher; Mussa-Ivaldi, Ferdinando A; Nisky, Ilana

2017-10-01

To adapt to deterministic force perturbations that depend on the current state of the hand, internal representations are formed to capture the relationships between forces experienced and motion. However, information from multiple modalities travels at different rates, resulting in intermodal delays that require compensation for these internal representations to develop. To understand how these delays are represented by the brain, we presented participants with delayed velocity-dependent force fields, i.e., forces that depend on hand velocity either 70 or 100 ms beforehand. We probed the internal representation of these delayed forces by examining the forces the participants applied to cope with the perturbations. The findings showed that for both delayed forces, the best model of internal representation consisted of a delayed velocity and current position and velocity. We show that participants relied initially on the current state, but with adaptation, the contribution of the delayed representation to adaptation increased. After adaptation, when the participants were asked to make movements with a higher velocity for which they had not previously experienced with the delayed force field, they applied forces that were consistent with current position and velocity as well as delayed velocity representations. This suggests that the sensorimotor system represents delayed force feedback using current and delayed state information and that it uses this representation when generalizing to faster movements. NEW & NOTEWORTHY The brain compensates for forces in the body and the environment to control movements, but it is unclear how it does so given the inherent delays in information transmission and processing. We examined how participants cope with delayed forces that depend on their arm velocity 70 or 100 ms beforehand. After adaptation, participants applied opposing forces that revealed a partially correct representation of the perturbation using the current and the

Multiconfiguration Pair-Density Functional Theory Outperforms Kohn-Sham Density Functional Theory and Multireference Perturbation Theory for Ground-State and Excited-State Charge Transfer.

Science.gov (United States)

Ghosh, Soumen; Sonnenberger, Andrew L; Hoyer, Chad E; Truhlar, Donald G; Gagliardi, Laura

2015-08-11

The correct description of charge transfer in ground and excited states is very important for molecular interactions, photochemistry, electrochemistry, and charge transport, but it is very challenging for Kohn-Sham (KS) density functional theory (DFT). KS-DFT exchange-correlation functionals without nonlocal exchange fail to describe both ground- and excited-state charge transfer properly. We have recently proposed a theory called multiconfiguration pair-density functional theory (MC-PDFT), which is based on a combination of multiconfiguration wave function theory with a new type of density functional called an on-top density functional. Here we have used MC-PDFT to study challenging ground- and excited-state charge-transfer processes by using on-top density functionals obtained by translating KS exchange-correlation functionals. For ground-state charge transfer, MC-PDFT performs better than either the PBE exchange-correlation functional or CASPT2 wave function theory. For excited-state charge transfer, MC-PDFT (unlike KS-DFT) shows qualitatively correct behavior at long-range with great improvement in predicted excitation energies.

Ground state energies from converging and diverging power series expansions

International Nuclear Information System (INIS)

Lisowski, C.; Norris, S.; Pelphrey, R.; Stefanovich, E.; Su, Q.; Grobe, R.

2016-01-01

It is often assumed that bound states of quantum mechanical systems are intrinsically non-perturbative in nature and therefore any power series expansion methods should be inapplicable to predict the energies for attractive potentials. However, if the spatial domain of the Schrödinger Hamiltonian for attractive one-dimensional potentials is confined to a finite length L, the usual Rayleigh–Schrödinger perturbation theory can converge rapidly and is perfectly accurate in the weak-binding region where the ground state’s spatial extension is comparable to L. Once the binding strength is so strong that the ground state’s extension is less than L, the power expansion becomes divergent, consistent with the expectation that bound states are non-perturbative. However, we propose a new truncated Borel-like summation technique that can recover the bound state energy from the diverging sum. We also show that perturbation theory becomes divergent in the vicinity of an avoided-level crossing. Here the same numerical summation technique can be applied to reproduce the energies from the diverging perturbative sums.

Ground state energies from converging and diverging power series expansions

Energy Technology Data Exchange (ETDEWEB)

Lisowski, C.; Norris, S.; Pelphrey, R.; Stefanovich, E., E-mail: eugene-stefanovich@usa.net; Su, Q.; Grobe, R.

2016-10-15

It is often assumed that bound states of quantum mechanical systems are intrinsically non-perturbative in nature and therefore any power series expansion methods should be inapplicable to predict the energies for attractive potentials. However, if the spatial domain of the Schrödinger Hamiltonian for attractive one-dimensional potentials is confined to a finite length L, the usual Rayleigh–Schrödinger perturbation theory can converge rapidly and is perfectly accurate in the weak-binding region where the ground state’s spatial extension is comparable to L. Once the binding strength is so strong that the ground state’s extension is less than L, the power expansion becomes divergent, consistent with the expectation that bound states are non-perturbative. However, we propose a new truncated Borel-like summation technique that can recover the bound state energy from the diverging sum. We also show that perturbation theory becomes divergent in the vicinity of an avoided-level crossing. Here the same numerical summation technique can be applied to reproduce the energies from the diverging perturbative sums.

2D XXZ model ground state properties using an analytic Lanczos expansion

International Nuclear Information System (INIS)

Witte, N.S.; Hollenberg, L.C.L.; Weihong Zheng

1997-01-01

A formalism was developed for calculating arbitrary expectation values for any extensive lattice Hamiltonian system using a new analytic Lanczos expansion, or plaquette expansion, and a recently proved exact theorem for ground state energies. The ground state energy, staggered magnetisation and the excited state gap of the 2D anisotropic antiferromagnetic Heisenberg Model are then calculated using this expansion for a range of anisotropy parameters and compared to other moment based techniques, such as the t-expansion, and spin-wave theory and series expansion methods. It was found that far from the isotropic point all moment methods give essentially very similar results, but near the isotopic point the plaquette expansion is generally better than the others. 20 refs., 6 tabs

Ground-state properties of K-isotopes from laser and $\\beta$-NMR spectroscopy

CERN Multimedia

Lievens, P; Rajabali, M M; Krieger, A R

By combining high-resolution laser spectroscopy with $\\beta$-NMR spectroscopy on polarized K-beams we aim to establish the ground-state spins and magnetic moments of the neutron-rich $^{48,49,50,51}$K isotopes from N=29 to N=32. Spins and magnetic moments of the odd-K isotopes up to N=28 reveal an inversion of the ground-state, from the normal $\\,{I}$=3/2 ($\\pi{d}_{3/2}^{-1}$) in $^{41-45}$K$\\to\\,{I}$=1/2 ($\\pi{s}_{1/2}^{-1}$) in $^{47}$K. This inversion of the proton single particle levels is related to the strong proton $d_{3/2}$ - neutron $f_{7/2}$ interaction which lowers the energy of the $\\pi{d}_{3/2}$ single particle state when filling the $\

Ground state solutions for asymptotically periodic Schrodinger equations with critical growth

Directory of Open Access Journals (Sweden)

Hui Zhang

2013-10-01

Full Text Available Using the Nehari manifold and the concentration compactness principle, we study the existence of ground state solutions for asymptotically periodic Schrodinger equations with critical growth.

On the ground state of the two-dimensional non-ideal Bose gas

International Nuclear Information System (INIS)

Lozovik, Yu.E.; Yudson, V.I.

1978-01-01

The theory of the ground state of the two-dimensional non-ideal Bose gas is presented. The conditions for the validity of the ladder and the Bogolubov approximations are derived. These conditions ensure the existence of a Bose condensate in the ground state of two-dimensional systems. These conditions are different from the corresponding conditions for the three-dimensional case. The connection between the effective interaction and the two-dimensional scattering amplitude at some characteristic energy kappa 2 /2m (not equal to 0) is obtained (f(kappa = 0) = infinity in the two-dimensional case). (Auth.)

Report on the Audit of Unattended Ground Sensor Systems

Science.gov (United States)

1991-02-26

This final report on the Audit of Unattended Ground Sensor Systems is for your information and use. Comments on the draft were considered in...preparing the final report and changes have been made where appropriate. We performed the audit from February through August 1990. The objective was to

Mapping to Estimate Health-State Utility from Non-Preference-Based Outcome Measures: An ISPOR Good Practices for Outcomes Research Task Force Report.

Science.gov (United States)

Wailoo, Allan J; Hernandez-Alava, Monica; Manca, Andrea; Mejia, Aurelio; Ray, Joshua; Crawford, Bruce; Botteman, Marc; Busschbach, Jan

2017-01-01

Economic evaluation conducted in terms of cost per quality-adjusted life-year (QALY) provides information that decision makers find useful in many parts of the world. Ideally, clinical studies designed to assess the effectiveness of health technologies would include outcome measures that are directly linked to health utility to calculate QALYs. Often this does not happen, and even when it does, clinical studies may be insufficient for a cost-utility assessment. Mapping can solve this problem. It uses an additional data set to estimate the relationship between outcomes measured in clinical studies and health utility. This bridges the evidence gap between available evidence on the effect of a health technology in one metric and the requirement for decision makers to express it in a different one (QALYs). In 2014, ISPOR established a Good Practices for Outcome Research Task Force for mapping studies. This task force report provides recommendations to analysts undertaking mapping studies, those that use the results in cost-utility analysis, and those that need to critically review such studies. The recommendations cover all areas of mapping practice: the selection of data sets for the mapping estimation, model selection and performance assessment, reporting standards, and the use of results including the appropriate reflection of variability and uncertainty. This report is unique because it takes an international perspective, is comprehensive in its coverage of the aspects of mapping practice, and reflects the current state of the art. Copyright © 2017 International Society for Pharmacoeconomics and Outcomes Research (ISPOR). Published by Elsevier Inc. All rights reserved.

Magnetic ground and remanent states of synthetic metamagnets with perpendicular anisotropy

International Nuclear Information System (INIS)

Kiselev, N S; Roessler, U K; Bogdanov, A N; Hellwig, O

2011-01-01

In this work, we summarize our theoretical results within a phenomenological micromagnetic approach for magnetic ground state and nonequilibrium states as topological magnetic defects in multilayers with strong perpendicular anisotropy and antiferromagnetic (AF) interlayer exchange coupling (IEC), e.g. [Co/Pt(Pd)]/Ru(Ir, NiO). We give detailed analysis of our model together with the most representative results which elucidate common features of such systems. We discuss phase diagrams of the magnetic ground state, and compare solutions of our model with experimental data. A model to assess the stability of so-called tiger tail patterns is presented. It is found that these modulated topological defect cannot be stabilized by an interplay between magnetostatic and IEC energies only. It is argued that tiger tail patterns arise as nuclei of ferro-stripe structure in AF domain walls and that they are stabilized by domain wall pinning.

Ground states for light and heavy quark hadrons

Energy Technology Data Exchange (ETDEWEB)

Anderson, J T [Physics Dept., Philippines Univ., Manila (Philippines)

1994-01-01

According to de Rujula et al. if the degenerate multiplet masses are known then it is not necessary to parametrize the interactions. With degenerate multiplet masses calculated from the spinorial decomposition of the SU(2)xSU(2) part of the SU(6)xSU(6) symmetry, the ground states for 3, 4 and 5 quark hadrons are calculated in terms of the Cartan matrix integers n[sub [alpha

Stride length: the impact on propulsion and bracing ground reaction force in overhand throwing.

Science.gov (United States)

Ramsey, Dan K; Crotin, Ryan L

2018-03-26

Propulsion and bracing ground reaction force (GRF) in overhand throwing are integral in propagating joint reaction kinetics and ball velocity, yet how stride length effects drive (hind) and stride (lead) leg GRF profiles remain unknown. Using a randomised crossover design, 19 pitchers (15 collegiate and 4 high school) were assigned to throw 2 simulated 80-pitch games at ±25% of their desired stride length. An integrated motion capture system with two force plates and radar gun tracked each throw. Vertical and anterior-posterior GRF was normalised then impulse was derived. Paired t-tests identified whether differences between conditions were significant. Late in single leg support, peak propulsion GRF was statistically greater for the drive leg with increased stride. Stride leg peak vertical GRF in braking occurred before acceleration with longer strides, but near ball release with shorter strides. Greater posterior shear GRF involving both legs demonstrated increased braking with longer strides. Conversely, decreased drive leg propulsion reduced both legs' braking effects with shorter strides. Results suggest an interconnection between normalised stride length and GRF application in propulsion and bracing. This work has shown stride length to be an important kinematic factor affecting the magnitude and timing of external forces acting upon the body.

Two-dimensional H2O-Cl2 and H2O-Br2 potential surfaces: an ab initio study of ground and valence excited electronic states.

Science.gov (United States)

Hernandez-Lamoneda, Ramón; Rosas, Victor Hugo Uc; Uruchurtu, Margarita I Bernal; Halberstadt, Nadine; Janda, Kenneth C

2008-01-10

All electron ab initio calculations for the interaction of H2O with Cl2 and Br2 are reported for the ground state and the lowest triplet and singlet Pi excited states as a function of both the X-X and O-X bond lengths (X = Cl or Br). For the ground state and lowest triplet state, the calculations are performed with the coupled cluster singles, doubles, and perturbative triple excitation level of correlation using an augmented triple-zeta basis set. For the 1Pi state the multireference average quadratic coupled cluster technique was employed. For several points on the potential, the calculations were repeated with the augmented quadruple-zeta basis set. The ground-state well depths were found to be 917 and 1,183 cm-1 for Cl2 and Br2, respectively, with the triple-zeta basis set, and they increased to 982 and 1,273 cm-1 for the quadruple-zeta basis set. At the geometry of the ground-state minimum, the lowest energy state corresponding to the unperturbed 1Pi states of the halogens increases in energy by 637 and 733 cm-1, respectively, relative to the ground-state dissociation limit of the H2O-X2 complex. Adding the attractive ground-state interaction energy to that of the repulsive excited state predicts a blue-shift, relative to that of the free halogen molecules, of approximately 1,600 cm-1 for H2O-Cl2 and approximately 2,000 cm-1 for H2O-Br2. These vertical blue-shifts for the dimers are greater than the shift of the band maximum upon solvation of either halogen in liquid water.

α-clustering in the ground state of 40Ca

International Nuclear Information System (INIS)

Michel, F.

1976-01-01

The anomalous large angle scattering observed in 40 Ca(α, α) is studied in the frame of a semi-microscopic model taking into account the presence of α-correlations in the ground state of 40 Ca. The calculations, performed between 18 and 29 MeV, assert the potential, non resonant nature of the phenomenon. (Auth.)

Report of the Task Force on radiopharmaceuticals

International Nuclear Information System (INIS)

Lacker, D.K.; Porter, B.J.; Watkins, G.

1975-01-01

The procedures for evaluation of IND and NDA applications were reviewed by FDA and the state members of the Task Force believe that there is significant progress being made toward expeditious handling of these items. Progress toward publication of the final rule on radiopharmaceuticals has reduced the need for state regulatory activity in investigational aspects of radiopharmaceutical research to the point that the original concept for the training is no longer valid

Study of ground-state configuration of neutron-rich aluminium isotopes through electromagnetic excitation

International Nuclear Information System (INIS)

Chakraborty, S.; Datta Pramanik, U.; Chatterjee, S.

2013-01-01

The region of the nuclear chart around neutron magic number, N∼20 and proton number (Z), 10≤ Z≤12 is known as the Island of Inversion. The valance neutron(s) of these nuclei, even in their ground state, are most likely occupying the upper pf orbitals which are normally lying above sd orbitals, N∼20 shell closure. Nuclei like 34,35 Al are lying at the boundary of this Island of Inversion. Little experimental information about their ground state configuration are available in literature

Ground state solutions for non-local fractional Schrodinger equations

Directory of Open Access Journals (Sweden)

Yang Pu

2015-08-01

Full Text Available In this article, we study a time-independent fractional Schrodinger equation with non-local (regional diffusion $$ (-\\Delta^{\\alpha}_{\\rho}u + V(xu = f(x,u \\quad \\text{in }\\mathbb{R}^{N}, $$ where $\\alpha \\in (0,1$, $N > 2\\alpha$. We establish the existence of a non-negative ground state solution by variational methods.

Search for C+ C clustering in Mg ground state

Indian Academy of Sciences (India)

2017-01-04

Jan 4, 2017 ... Finite-range knockout theory predictions were much larger for (12C,212C) reaction, indicating a very small 12C−12C clustering in 24Mg. (g.s.) . Our present results contradict most of the proposed heavy cluster (12C+12C) structure models for the ground state of 24Mg. Keywords. Direct nuclear reactions ...

Ground Radio Operator Career Ladder AFSC 293X3.

Science.gov (United States)

1981-07-01

formal resident training, OJT, and ,her Air Force management decisions . The structure of jobs within the Ground ! odio Operatoi career ladder was...33 ADJUST ANTENNA TUNING UNITS 33 TYPE RECORDS, REPORTS, OR FORMS :33 OPERATE AUXILLARY GENERATORS 33 A8 ’iT’ TASKS PERFORMED BY SUPERVISORS AND

The ground state energy of 3He droplet in the LOCV framework

International Nuclear Information System (INIS)

Modarres, M.; Motahari, S.; Rajabi, A.

2012-01-01

The (extended) lowest order constrained variational method was used to calculate the ground state energy of liquid helium 3 ( 3 He) droplets at zero temperature. Different types of density distribution profiles, such as the Gaussian, the Quasi-Gaussian and the Woods-Saxon were used. It was shown that at least, on average, near 20 3 He atoms are needed to get the bound state for 3 He liquid droplet. Depending on the choice of the density profiles and the atomic radius of 3 He, the above estimate can increase to 300. Our calculated ground state energy and the number of atoms in liquid 3 He droplet were compared with those of Variational Monte Carlo method, Diffusion Monte Carlo method and Density Functional Theory, for which a reasonable agreement was found.

18 CFR 430.19 - Ground water withdrawal metering, recording, and reporting.

Science.gov (United States)

2010-04-01

... 18 Conservation of Power and Water Resources 2 2010-04-01 2010-04-01 false Ground water withdrawal metering, recording, and reporting. 430.19 Section 430.19 Conservation of Power and Water Resources DELAWARE RIVER BASIN COMMISSION SPECIAL REGULATIONS GROUND WATER PROTECTION AREA: PENNSYLVANIA § 430.19...

A grounded theory of young tennis players use of music to manipulate emotional state.

Science.gov (United States)

Bishop, Daniel T; Karageorghis, Costas I; Loizou, Georgios

2007-10-01

The main objectives of this study were (a) to elucidate young tennis players' use of music to manipulate emotional states, and (b) to present a model grounded in present data to illustrate this phenomenon and to stimulate further research. Anecdotal evidence suggests that music listening is used regularly by elite athletes as a preperformance strategy, but only limited empirical evidence corroborates such use. Young tennis players (N = 14) were selected purposively for interview and diary data collection. Results indicated that participants consciously selected music to elicit various emotional states; frequently reported consequences of music listening included improved mood, increased arousal, and visual and auditory imagery. The choice of music tracks and the impact of music listening were mediated by a number of factors, including extramusical associations, inspirational lyrics, music properties, and desired emotional state. Implications for the future investigation of preperformance music are discussed.

Propagation of the state change induced by external forces in local interactions

Science.gov (United States)

Lu, Jianjun; Tokinaga, Shozo

2016-10-01

This paper analyses the propagation of the state changes of agents that are induced by external forces applied to a plane. In addition, we propose two models for the behavior of the agents placed on a lattice plane, both of which are affected by local interactions. We first assume that agents are allowed to move to another site to maximise their satisfaction. Second, we utilise a model in which the agents choose activities on each site. The results show that the migration (activity) patterns of agents in both models achieve stability without any external forces. However, when we apply an impulsive external force to the state of the agents, we then observe the propagation of the changes in the agents' states. Using simulation studies, we show the conditions for the propagation of the state changes of the agents. We also show the propagation of the state changes of the agents allocated in scale-free networks and discuss the estimation of the agents' decisions in real state changes. Finally, we discuss the estimation of the agents' decisions in real state temporal changes using economic and social data from Japan and the United States.

Probing the 8He ground state via the 8He(p,t)6He reaction

International Nuclear Information System (INIS)

Keeley, N.; Skaza, F.; Lapoux, V.; Alamanos, N.; Auger, F.; Beaumel, D.; Becheva, E.; Blumenfeld, Y.; Delaunay, F.; Drouart, A.; Gillibert, A.; Giot, L.; Kemper, K.W.; Nalpas, L.; Pakou, A.; Pollacco, E.C.; Raabe, R.; Roussel-Chomaz, P.; Rusek, K.; Scarpaci, J.-A.; Sida, J.-L.; Stepantsov, S.; Wolski, R.

2007-01-01

The weakly-bound 8 He nucleus exhibits a neutron halo or thick neutron skin and is generally considered to have an α+4n structure in its ground state, with the four valence neutrons each occupying 1p 3/2 states outside the α core. The 8 He(p,t) 6 He reaction is a sensitive probe of the ground state structure of 8 He, and we present a consistent analysis of new and existing data for this reaction at incident energies of 15.7 and 61.3A MeV, respectively. Our results are incompatible with the usual assumption of a pure (1p 3/2 ) 4 structure and suggest that other configurations such as (1p 3/2 ) 2 (1p 1/2 ) 2 may be present with significant probability in the ground state wave function of 8 He

Numerical study of the t-J model: Exact ground state and flux phases

International Nuclear Information System (INIS)

Hasegawa, Y.; Poilblanc, D.

1990-01-01

Strongly correlated 2D electrons described by the t-J model are investigated numerically. Exact ground state for one and two holes in a finite cluster with periodic boundary conditions are obtained by using the Lanczos algorithm. The effects of Coulomb repulsion of the holes on the nearest neighbor sites are taken into account. Commensurate flux phases are investigated for the same size of clusters. They are shown to be a good approximation for the ground state specially in the intermediate value of J/t. (author). 21 refs, 3 figs

Zethrenes, Extended p -Quinodimethanes, and Periacenes with a Singlet Biradical Ground State

KAUST Repository

Sun, Zhe

2014-08-19

ConspectusResearchers have studied polycyclic aromatic hydrocarbons (PAHs) for more than 100 years, and most PAHs in the neutral state reported so far have a closed-shell electronic configuration in the ground state. However, recent studies have revealed that specific types of polycyclic hydrocarbons (PHs) could have a singlet biradical ground state and exhibit unique electronic, optical, and magnetic activities. With the appropriate stabilization, these new compounds could prove useful as molecular materials for organic electronics, nonlinear optics, organic spintronics, organic photovoltaics, and energy storage devices. However, before researchers can use these materials to design new devices, they need better methods to synthesize these molecules and a better understanding of the fundamental relationship between the structure and biradical character of these compounds and their physical properties. Their biradical character makes these compounds difficult to synthesize. These compounds are also challenging to physically characterize and require the use of various experimental techniques and theoretic methods to comprehensively describe their unique properties.In this Account, we will discuss the chemistry and physics of three types of PHs with a significant singlet biradical character, primarily developed in our group. These structures are zethrenes, Z-shaped quinoidal hydrocarbons; hydrocarbons that include a proaromatic extended p-quinodimethane unit; and periacenes, acenes fused in a peri-Arrangement. We used a variety of synthetic methods to prepare these compounds and stabilized them using both thermodynamic and kinetic approaches. We probed their ground-state structures by electronic absorption, NMR, ESR, SQUID, Raman spectroscopy, and X-ray crystallography and also performed density functional theory calculations. We investigated the physical properties of these PHs using various experimental methods such as one-photon absorption, two-photon absorption

The properties of 4'-N,N-dimethylaminoflavonol in the ground and excited states

Science.gov (United States)

Moroz, V. V.; Chalyi, A. G.; Roshal, A. D.

2008-09-01

The mechanism of protonation of 4-N,N-dimethylaminoflavonol and the structure of its protolytic forms in the ground and excited states were studied by electron absorption and fluorescence (steady-state and time-resolved) spectroscopy and with the use of the RM1 quantum-chemical method. A comparison of equilibrium constants and the theoretical enthalpies of formation showed that excitation should be accompanied by the inversion of the basicity of the electron acceptor groups of this compound and, as a consequence, changes in the structure of its monocationic form. An analysis of the spectral parameters of the protolytic 4-N,N-dimethylaminoflavonol forms, however, showed that their structure and the sequence of protonation in the excited state were the same as in the ground state. Changes in the structure of the monocation in the excited state were not observed because of the fast radiationless deactivation of this form and the occurrence of excited state intramolecular proton transfer in aprotic solvents.

Implementation of rigorous renormalization group method for ground space and low-energy states of local Hamiltonians

Science.gov (United States)

Roberts, Brenden; Vidick, Thomas; Motrunich, Olexei I.

2017-12-01

The success of polynomial-time tensor network methods for computing ground states of certain quantum local Hamiltonians has recently been given a sound theoretical basis by Arad et al. [Math. Phys. 356, 65 (2017), 10.1007/s00220-017-2973-z]. The convergence proof, however, relies on "rigorous renormalization group" (RRG) techniques which differ fundamentally from existing algorithms. We introduce a practical adaptation of the RRG procedure which, while no longer theoretically guaranteed to converge, finds matrix product state ansatz approximations to the ground spaces and low-lying excited spectra of local Hamiltonians in realistic situations. In contrast to other schemes, RRG does not utilize variational methods on tensor networks. Rather, it operates on subsets of the system Hilbert space by constructing approximations to the global ground space in a treelike manner. We evaluate the algorithm numerically, finding similar performance to density matrix renormalization group (DMRG) in the case of a gapped nondegenerate Hamiltonian. Even in challenging situations of criticality, large ground-state degeneracy, or long-range entanglement, RRG remains able to identify candidate states having large overlap with ground and low-energy eigenstates, outperforming DMRG in some cases.

The magnetic ground state and relationship to Kitaev physics in α-RuCl3

Science.gov (United States)

Banerjee, Arnab

The 2D Kitaev candidate alpha-RuCl3 consists of stacked honeycomb layers weakly coupled by Van der Waals interactions. Here we report the measurements of bulk properties and neutron diffraction in both powder and single crystal samples. Our results show that the full three dimensional magnetic ground state is highly pliable with at least two dominant phases corresponding to two different out-of-plane magnetic orders. They have different Neel temperatures dependent on the stacking of the 2D layers, such as a broad magnetic transition at TN = 14 K as observed in phase-pure powder samples, or a sharp magnetic transition at a lower TN = 7 K as observed in homogeneous single crystals with no evidence for stacking faults. The magnetic refinements of the neutron scattering data will be discussed, which in all cases shows the in-plane magnetic ground state is the zigzag phase common in Kitaev related materials including the honeycomb lattice Iridates. Inelastic neutron scattering in all cases shows that this material consistently exhibit strong two-dimensional magnetic fluctuations leading to a break-down of the classical spin-wave picture. Work performed at ORNL is supported by U.S. Dept. of Energy, Office of Basic Energy Sciences and Office of User Facilities Division.

Hartree–Fock many-body perturbation theory for nuclear ground-states

Directory of Open Access Journals (Sweden)

Alexander Tichai

2016-05-01

Full Text Available We investigate the order-by-order convergence behavior of many-body perturbation theory (MBPT as a simple and efficient tool to approximate the ground-state energy of closed-shell nuclei. To address the convergence properties directly, we explore perturbative corrections up to 30th order and highlight the role of the partitioning for convergence. The use of a simple Hartree–Fock solution for the unperturbed basis leads to a convergent MBPT series for soft interactions, in contrast to the divergent MBPT series obtained with a harmonic oscillator basis. For larger model spaces and heavier nuclei, where a direct high-order MBPT calculation is not feasible, we perform third-order calculations and compare to advanced ab initio coupled-cluster results for the same interactions and model spaces. We demonstrate that third-order MBPT provides ground-state energies for nuclei up into the tin isotopic chain in excellent agreement with the best available coupled-cluster calculations at a fraction of the computational cost.

Hartree–Fock many-body perturbation theory for nuclear ground-states

Energy Technology Data Exchange (ETDEWEB)

Tichai, Alexander, E-mail: alexander.tichai@physik.tu-darmstadt.de [Institut für Kernphysik, Technische Universität Darmstadt, 64289 Darmstadt (Germany); Langhammer, Joachim [Institut für Kernphysik, Technische Universität Darmstadt, 64289 Darmstadt (Germany); Binder, Sven [Department of Physics and Astronomy, University of Tennessee, Knoxville, TN 37996 (United States); Physics Division, Oak Ridge National Laboratory, Oak Ridge, TN 37831 (United States); Roth, Robert, E-mail: robert.roth@physik.tu-darmstadt.de [Institut für Kernphysik, Technische Universität Darmstadt, 64289 Darmstadt (Germany)

2016-05-10

We investigate the order-by-order convergence behavior of many-body perturbation theory (MBPT) as a simple and efficient tool to approximate the ground-state energy of closed-shell nuclei. To address the convergence properties directly, we explore perturbative corrections up to 30th order and highlight the role of the partitioning for convergence. The use of a simple Hartree–Fock solution for the unperturbed basis leads to a convergent MBPT series for soft interactions, in contrast to the divergent MBPT series obtained with a harmonic oscillator basis. For larger model spaces and heavier nuclei, where a direct high-order MBPT calculation is not feasible, we perform third-order calculations and compare to advanced ab initio coupled-cluster results for the same interactions and model spaces. We demonstrate that third-order MBPT provides ground-state energies for nuclei up into the tin isotopic chain in excellent agreement with the best available coupled-cluster calculations at a fraction of the computational cost.

Observation of Hyperfine Transitions in Trapped Ground-State Antihydrogen

CERN Document Server

Olin, Arthur

2015-01-01

This paper discusses the first observation of stimulated magnetic resonance transitions between the hyperfine levels of trapped ground state atomic antihydrogen, confirming its presence in the ALPHA apparatus. Our observations show that these transitions are consistent with the values in hydrogen to within 4~parts~in~$10^3$. Simulations of the trapped antiatoms in a microwave field are consistent with our measurements.

Observation of hyperfine transitions in trapped ground-state antihydrogen

Energy Technology Data Exchange (ETDEWEB)

Collaboration: A. Olin for the ALPHA Collaboration

2015-08-15

This paper discusses the first observation of stimulated magnetic resonance transitions between the hyperfine levels of trapped ground state atomic antihydrogen, confirming its presence in the ALPHA apparatus. Our observations show that these transitions are consistent with the values in hydrogen to within 4 parts in 10{sup 3}. Simulations of the trapped antiatoms in a microwave field are consistent with our measurements.

Gamma-point lattice free energy estimates from O(1) force calculations

DEFF Research Database (Denmark)

Voss, Johannes; Vegge, Tejs

2008-01-01

We present a new method for estimating the vibrational free energy of crystal (and molecular) structures employing only a single force calculation, for a particularly displaced configuration, in addition to the calculation of the ground state configuration. This displacement vector is the sum...

GRASP [GRound-Water Adjunct Sensitivity Program]: A computer code to perform post-SWENT [simulator for water, energy, and nuclide transport] adjoint sensitivity analysis of steady-state ground-water flow: Technical report

International Nuclear Information System (INIS)

Wilson, J.L.; RamaRao, B.S.; McNeish, J.A.

1986-11-01

GRASP (GRound-Water Adjunct Senstivity Program) computes measures of the behavior of a ground-water system and the system's performance for waste isolation, and estimates the sensitivities of these measures to system parameters. The computed measures are referred to as ''performance measures'' and include weighted squared deviations of computed and observed pressures or heads, local Darcy velocity components and magnitudes, boundary fluxes, and travel distance and time along travel paths. The sensitivities are computed by the adjoint method and are exact derivatives of the performance measures with respect to the parameters for the modeled system, taken about the assumed parameter values. GRASP presumes steady-state, saturated grondwater flow, and post-processes the results of a multidimensional (1-D, 2-D, 3-D) finite-difference flow code. This document describes the mathematical basis for the model, the algorithms and solution techniques used, and the computer code design. The implementation of GRASP is verified with simple one- and two-dimensional flow problems, for which analytical expressions of performance measures and sensitivities are derived. The linkage between GRASP and multidimensional finite-difference flow codes is described. This document also contains a detailed user's manual. The use of GRASP to evaluate nuclear waste disposal issues has been emphasized throughout the report. The performance measures and their sensitivities can be employed to assist in directing data collection programs, expedite model calibration, and objectively determine the sensitivity of projected system performance to parameters

A Full Cost Analysis of the Replacement of Naval Base, Guantanamo Bay's Marine Ground Defense Force by the Fleet Antiterrorism Security Team

National Research Council Canada - National Science Library

Ordona, Placido

2000-01-01

... of these diminishing resources. One such initiative is the restructuring of the Marine security presence at Naval Station, Guantanamo Bay, Cuba, through the replacement of the 350 man Marine Ground Defense Force with a smaller...

Electron-impact excitation and ionization cross sections for ground state and excited helium atoms

International Nuclear Information System (INIS)

Ralchenko, Yu.; Janev, R.K.; Kato, T.; Fursa, D.V.; Bray, I.; Heer, F.J. de

2008-01-01

Comprehensive and critically assessed cross sections for the electron-impact excitation and ionization of ground state and excited helium atoms are presented. All states (atomic terms) with n≤4 are treated individually, while the states with n≥5 are considered degenerate. For the processes involving transitions to and from n≥5 levels, suitable cross section scaling relations are presented. For a large number of transitions, from both ground and excited states, convergent close coupling calculations were performed to achieve a high accuracy of the data. The evaluated/recommended cross section data are presented by analytic fit functions, which preserve the correct asymptotic behavior of the cross sections. The cross sections are also displayed in graphical form

Van der Waals potential and vibrational energy levels of the ground state radon dimer

Science.gov (United States)

Sheng, Xiaowei; Qian, Shifeng; Hu, Fengfei

2017-08-01

In the present paper, the ground state van der Waals potential of the Radon dimer is described by the Tang-Toennies potential model, which requires five essential parameters. Among them, the two dispersion coefficients C6 and C8 are estimated from the well determined dispersion coefficients C6 and C8 of Xe2. C10 is estimated by using the approximation equation that C6C10/C82 has an average value of 1.221 for all the rare gas dimers. With these estimated dispersion coefficients and the well determined well depth De and Re the Born-Mayer parameters A and b are derived. Then the vibrational energy levels of the ground state radon dimer are calculated. 40 vibrational energy levels are observed in the ground state of Rn2 dimer. The last vibrational energy level is bound by only 0.0012 cm-1.

Ground-water conditions in Utah, spring of 1995

Science.gov (United States)

Allen, D.V.; Steiger, J.I.; Sory, J.D.; Garrett, R.B.; Burden, Carole B.; Danner, M.R.; Herbert, L.R.; Gerner, S.J.; Slaugh, B.A.; Swenson, R.L.; Howells, J.H.; Christiansen, H.K.; Bagley, A.D.

1995-01-01

This is the thirty-second in a series of annual reports that describe ground-water conditions in Utah. Reports in this series, published cooperatively by the U.S. Geological Survey and the Utah Department of Natural Resources, Division of Water Resources, provide data to enable interested parties to keep abreast of changing ground-water conditions.This report, like the others in the series, contains information on well construction, ground-water withdrawal from wells, water-level changes, related changes in precipitation and streamflow, and chemical quality of water. Supplementary data, such as maps showing water-level contours, are included in reports of this series only for those years or areas for which applicable data are available and are important to a discussion of changing ground-water conditions.This report includes individual discussions of selected significant areas of ground-water development in the State for calendar year 1994. Much of the reported data were collected by the U.S. Geological Survey in cooperation with the Utah Department of Natural Resources, Divisions of Water Rights and Water Resources.

Ground-state candidate for the classical dipolar kagome Ising antiferromagnet

Science.gov (United States)

Chioar, I. A.; Rougemaille, N.; Canals, B.

2016-06-01

We have investigated the low-temperature thermodynamic properties of the classical dipolar kagome Ising antiferromagnet using Monte Carlo simulations, in the quest for the ground-state manifold. In spite of the limitations of a single-spin-flip approach, we managed to identify certain ordering patterns in the low-temperature regime and we propose a candidate for this unknown state. This configuration presents some intriguing features and is fully compatible with the extrapolations of the at-equilibrium thermodynamic behavior sampled so far, making it a very likely choice for the dipolar long-range ordered state of the classical kagome Ising antiferromagnet.

Electronic transitions and intermolecular forces

International Nuclear Information System (INIS)

Hemert, M.C. van.

1981-01-01

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.)

Ground-water elements of in situ leach mining of uranium. Final report

International Nuclear Information System (INIS)

Thompson, W.E.; Swarzenski, W.V.; Warner, D.L.; Rouse, G.E.; Carrington, O.F.; Pyrih, R.Z.

1978-07-01

This report provides methods to collect data and evaluates impacts concerning ground-water elements of production-scale leach mining of uranium. Two overlapping networks of monitor wells are designed to collect premining hydrogeologic and baseline water-quality data and to detect excursions of leaching fluids. The pre-mining data collection network consists of 24 wells completed into the ore-zone aquifer and the water-bearing units above and below it. The excursion-monitor network utilizes two rings of wells encircling the ore body and other wells strategically placed into other water-bearing units. The lateral excursion detection system is keyed to changes in water levels whereas the vertical excursion detection system is keyed to changes in water quality. Several ground-water restoration methods are evaluated. Mechanical and chemical restoration methods can significantly remove most introduced and mobilized chemicals. Natural geochemical mechanisms should be capable of causing water-quality improvement. Several water-quality constituents, i.e., ammonia, chloride, sulfate, may not be greatly affected by restoration efforts. Most mining and restoration activities should not greatly affect the availability or usefulness of ground water unless uncontrolled withdrawals from many sources occur. Disposal of leach mining wastes may prove a greater threat to the environment than the mining. Natural conditions and/or current state and Federal regulations limit the types of disposal methods that may be used

Random interactions, isospin, and the ground states of odd-A and odd-odd nuclei

International Nuclear Information System (INIS)

Horoi, Mihai; Volya, Alexander; Zelevinsky, Vladimir

2002-01-01

It was recently shown that the ground state quantum numbers of even-even nuclei have a high probability to be reproduced by an ensemble of random but rotationally invariant two-body interactions. In the present work we extend these investigations to odd-A and odd-odd nuclei, considering in particular the isospin effects. Studying the realistic shell model as well as the single-j model, we show that random interactions have a tendency to assign the lowest possible total angular momentum and isospin to the ground state. In the sd shell model this reproduces correctly the isospin but not the spin quantum numbers of actual odd-odd nuclei. An odd-even staggering effect in probability of various ground state quantum numbers is present for even-even and odd-odd nuclei, while it is smeared out for odd-A nuclei. The observed regularities suggest the underlying mechanism of bosonlike pairing of fermionic pairs in T=0 and T=1 states generated by the off-diagonal matrix elements of random interactions. The relation to the models of random spin interactions is briefly discussed

THE DECENNIAL OF AIR FORCE SPACE COMMAND’S ONLY GROUND BASED MISSILE WARNING CLASSIC ASSOCIATE UNIT: BENEFITS, DRAWBACKS, AND CHALLENGES

Science.gov (United States)

2016-02-16

Fulfillment of the Graduation Requirements Proposal Adviser: Dr. Patricia Lessane Project Advisor: Dr. Gregory F. Intoccia Maxwell Air Force Base, Alabama... SBIRS ), and Ground Based Missile Warning Radars (GBMWR). 7 In unison, these assets monitor ballistic missile launches and help prevent surprise

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…

Ground-state energy of an exciton-(LO) phonon system in a parabolic quantum well

Science.gov (United States)

Gerlach, B.; Wüsthoff, J.; Smondyrev, M. A.

1999-12-01

This paper presents a variational study of the ground-state energy of an exciton-(LO) phonon system, which is spatially confined to a quantum well. The exciton-phonon interaction is of Fröhlich type, the confinement potentials are assumed to be parabolic functions of the coordinates. Making use of functional integral techniques, the phonon part of the problem can be eliminated exactly, leading us to an effective two-particle system, which has the same spectral properties as the original one. Subsequently, Jensen's inequality is applied to obtain an upper bound on the ground-state energy. The main intention of this paper is to analyze the influence of the quantum-well-induced localization of the exciton on its ground-state energy (or its binding energy, respectively). To do so, we neglect any mismatch of the masses or the dielectric constants, but admit an arbitrary strength of the confinement potentials. Our approach allows for a smooth interpolation of the ultimate limits of vanishing and infinite confinement, corresponding to the cases of a free three-dimensional and a free two-dimensional exciton-phonon system. The interpolation formula for the ground-state energy bound corresponds to similar formulas for the free polaron or the free exciton-phonon system. These bounds in turn are known to compare favorably with all previous ones, which we are aware of.

Identification of technical guidance related to ground water monitoring

Energy Technology Data Exchange (ETDEWEB)

Vogelsberger, R.R.; Smith, E.D.; Broz, M.; Wright, J.C. Jr.

1987-05-01

Monitoring of ground water quality is a key element of ground water protection and is mandated by several federal and state laws concerned with water quality or waste management. Numerous regulatory guidance documents and technical reports discuss various aspects of ground water monitoring, but at present there is no single source of guidance on procedures and practices for ground water monitoring. This report is intended to assist US Department of Energy (DOE) officials and facility operating personnel in identifying sources of guidance for developing and implementing ground water monitoring programs that are technically sound and that comply with applicable regulations. Federal statutes and associated regulations were reviewed to identify requirements related to ground water monitoring, and over 160 documents on topics related to ground water monitoring were evaluated for their technical merit, their utility as guidance for regulatory compliance, and their relevance to DOE's needs. For each of 15 technical topics involved in ground water monitoring, the report presents (1) a review of federal regulatory requirements and representative state requirements, (2) brief descriptions of the contents and merits of available guidance documents and technical references, and (3) recommendations of the guidance documents or other technical resources that appear to be most appropriate for use in DOE's monitoring activities. The contents of the report are applicable to monitoring activities involving both radioactive and nonradioactive substances. The main sources of regulatory requirements considered in the report are the Atomic Energy Act (including the Uranium Mill Tailings Radiation Control Act), Resource Conservation and Recovery Act, Comprehensive Environmental Response, Compensation and Liability Act, Safe Drinking Water Act, Toxic Substances Control Act, and Federal Water Pollution Control Act.

Identification of technical guidance related to ground water monitoring

International Nuclear Information System (INIS)

Vogelsberger, R.R.; Smith, E.D.; Broz, M.; Wright, J.C. Jr.

1987-05-01

Monitoring of ground water quality is a key element of ground water protection and is mandated by several federal and state laws concerned with water quality or waste management. Numerous regulatory guidance documents and technical reports discuss various aspects of ground water monitoring, but at present there is no single source of guidance on procedures and practices for ground water monitoring. This report is intended to assist US Department of Energy (DOE) officials and facility operating personnel in identifying sources of guidance for developing and implementing ground water monitoring programs that are technically sound and that comply with applicable regulations. Federal statutes and associated regulations were reviewed to identify requirements related to ground water monitoring, and over 160 documents on topics related to ground water monitoring were evaluated for their technical merit, their utility as guidance for regulatory compliance, and their relevance to DOE's needs. For each of 15 technical topics involved in ground water monitoring, the report presents (1) a review of federal regulatory requirements and representative state requirements, (2) brief descriptions of the contents and merits of available guidance documents and technical references, and (3) recommendations of the guidance documents or other technical resources that appear to be most appropriate for use in DOE's monitoring activities. The contents of the report are applicable to monitoring activities involving both radioactive and nonradioactive substances. The main sources of regulatory requirements considered in the report are the Atomic Energy Act (including the Uranium Mill Tailings Radiation Control Act), Resource Conservation and Recovery Act, Comprehensive Environmental Response, Compensation and Liability Act, Safe Drinking Water Act, Toxic Substances Control Act, and Federal Water Pollution Control Act

Effect of fatigue on force production and force application technique during repeated sprints.

Science.gov (United States)

Morin, Jean-Benoit; Samozino, Pierre; Edouard, Pascal; Tomazin, Katja

2011-10-13

We investigated the changes in the technical ability of force application/orientation against the ground vs. the physical capability of total force production after a multiple-set repeated sprints series. Twelve male physical education students familiar with sprint running performed four sets of five 6-s sprints (24s of passive rest between sprints, 3min between sets). Sprints were performed from a standing start on an instrumented treadmill, allowing the computation of vertical (F(V)), net horizontal (F(H)) and total (F(Tot)) ground reaction forces for each step. Furthermore, the ratio of forces was calculated as RF=F(H)F(Tot)(-1), and the index of force application technique (D(RF)) representing the decrement in RF with increase in speed was computed as the slope of the linear RF-speed relationship. Changes between pre- (first two sprints) and post-fatigue (last two sprints) were tested using paired t-tests. Performance decreased significantly (e.g. top speed decreased by 15.7±5.4%; Pmultiple-set repeated sprint series, both the total force production capability and the technical ability to apply force effectively against the ground are altered, the latter to a larger extent than the former. Copyright © 2011 Elsevier Ltd. All rights reserved.

Anisotropic spin motive force in multi-layered Dirac fermion system, α-(BEDT-TTF)2I3

International Nuclear Information System (INIS)

Kubo, K; Morinari, T

2015-01-01

We investigate the anisotropic spin motive force in α-(BEDT-TTF) 2 I 3 , which is a multi-layered massless Dirac fermion system under pressure. Assuming the interlayer antiferromagnetic interaction and the interlayer anisotropic ferromagnetic interaction, we numerically examine the spin ordered state of the ground state using the steepest descent method. The anisotropic interaction leads to the anisotropic spin ordered state. We calculate the spin motive force produced by the anisotropic spin texture. The result quantitatively agrees with the experiment. (paper)

Alteration of the ground state by external magnetic fields. [External field, coupling constant ratio, static tree level approximation

Energy Technology Data Exchange (ETDEWEB)

Harrington, B J; Shepard, H K [New Hampshire Univ., Durham (USA). Dept. of Physics

1976-03-22

By fully exploiting the mathematical and physical analogy to the Ginzburg-Landau theory of superconductivity, a complete discussion of the ground state behavior of the four-dimensional Abelian Higgs model in the static tree level approximation is presented. It is shown that a sufficiently strong external magnetic field can alter the ground state of the theory by restoring a spontaneously broken symmetry, or by creating a qualitatively different 'vortex' state. The energetically favored ground state is explicitly determined as a function of the external field and the ratio between coupling constants of the theory.