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1

Object motiondecoupled internal force control for a compliant multifingered hand  

E-print Network

Object motion­decoupled internal force control for a compliant multifingered hand Domenico, and on the contact properties. In object grasping the primary task of the robotic hand is the control of internal degradation. This paper studies the structural conditions to design an internal force controller decoupled

Siena, Università di

2

Industrial Energy Conservation, Forced Internal Recirculation Burner  

SciTech Connect

The overall objective of this research project is to develop and evaluate an industrial low NOx burner for existing and new gas-fired combustion systems for intermediate temperature (1400 degree to 2000 degree F) industrial heating devices such as watertube boilers and process fluid heaters. A multi-phase effort is being pursued with decision points to determine advisability of continuance. The current contract over Phases II and III of this work. The objectives of each phase are as follows. Phase II - to design, fabricate, and evaluate prototype burners based on the Forced Internal Recirculation (FIR) concept. Phase III - to evaluate the performance of an FIR burner under actual operating conditions in a full-scale field test and establish the performance necessary for subsequent commercialization

Joseph Rabovitser

2003-06-19

3

77 FR 29899 - Safety Zone; International Special Operations Forces Week Capability Exercise, Seddon Channel...  

Federal Register 2010, 2011, 2012, 2013

...International Special Operations Forces Week Capability Exercise, Seddon Channel...International Special Operations Forces Week Capability Exercise. The exercise is scheduled...International Special Operations Forces Week Capability Exercise is scheduled to...

2012-05-21

4

Locomotive and reptation motion induced by internal force and friction  

E-print Network

We propose a simple mechanical model of locomotion induced by internal force and friction. We first construct a system of two elements as an analog of the bipedal motion. The internal force does not induce a directional motion by itself because of the action-reaction law, but a directional motion becomes possible by the control of the frictional force. The efficiency of these model systems is studied using an analogy to the heat engine. As a modified version of the two-elements model, we construct a model which exhibits a bipedal motion similar to kinesin's motion of molecular motor. Next, we propose a linear chain model and a ladder model as an extension of the original two-element model,. We find a transition from a straight to a snake-like motion in a ladder model by changing the strength of the internal force.

Hidetsugu Sakaguchi; Taisuke Ishihara

2011-05-06

5

The Internal Forces of Creativity: When Hearts Start to Flutter.  

ERIC Educational Resources Information Center

Four artistic people of various ages were interviewed concerning their conscious and unconscious thought during creative activity, emotions which precipitated creative activity and intermingled with cognition, and intrinsic motivators and rewards. The interviews supported research regarding the internal forces of creativity. (Author/JDD)

Gnezda-Smith, Nicole

1994-01-01

6

On forced temperature changes, internal variability, and the AMO  

NASA Astrophysics Data System (ADS)

estimate the low-frequency internal variability of Northern Hemisphere (NH) mean temperature using observed temperature variations, which include both forced and internal variability components, and several alternative model simulations of the (natural + anthropogenic) forced component alone. We then generate an ensemble of alternative historical temperature histories based on the statistics of the estimated internal variability. Using this ensemble, we show, first, that recent NH mean temperatures fall within the range of expected multidecadal variability. Using the synthetic temperature histories, we also show that certain procedures used in past studies to estimate internal variability, and in particular, an internal multidecadal oscillation termed the "Atlantic Multidecadal Oscillation" or "AMO", fail to isolate the true internal variability when it is a priori known. Such procedures yield an AMO signal with an inflated amplitude and biased phase, attributing some of the recent NH mean temperature rise to the AMO. The true AMO signal, instead, appears likely to have been in a cooling phase in recent decades, offsetting some of the anthropogenic warming. Claims of multidecadal "stadium wave" patterns of variation across multiple climate indices are also shown to likely be an artifact of this flawed procedure for isolating putative climate oscillations.

Mann, Michael E.; Steinman, Byron A.; Miller, Sonya K.

2014-05-01

7

Forcing, feedback and internal variability in global temperature trends.  

PubMed

Most present-generation climate models simulate an increase in global-mean surface temperature (GMST) since 1998, whereas observations suggest a warming hiatus. It is unclear to what extent this mismatch is caused by incorrect model forcing, by incorrect model response to forcing or by random factors. Here we analyse simulations and observations of GMST from 1900 to 2012, and show that the distribution of simulated 15-year trends shows no systematic bias against the observations. Using a multiple regression approach that is physically motivated by surface energy balance, we isolate the impact of radiative forcing, climate feedback and ocean heat uptake on GMST--with the regression residual interpreted as internal variability--and assess all possible 15- and 62-year trends. The differences between simulated and observed trends are dominated by random internal variability over the shorter timescale and by variations in the radiative forcings used to drive models over the longer timescale. For either trend length, spread in simulated climate feedback leaves no traceable imprint on GMST trends or, consequently, on the difference between simulations and observations. The claim that climate models systematically overestimate the response to radiative forcing from increasing greenhouse gas concentrations therefore seems to be unfounded. PMID:25631444

Marotzke, Jochem; Forster, Piers M

2015-01-29

8

Forced wave motion with internal and boundary damping  

NASA Astrophysics Data System (ADS)

A d'Alembert-based solution of forced wave motion with internal and boundary damping is presented with the specific intention of investigating the transient response. The dynamic boundary condition is a convenient method to model the absorption and reflection effects of an interface without considering coupled PDE's. Problems with boundary condition of the form ?w/?z+??w/?t =0 are not self-adjoint which greatly complicates solution by spectral analysis. However, exact solutions are found with d'Alembert's method. Solutions are also derived for a time-harmonically forced problem with internal damping and are used to investigate the effect of ultrasound in a bioreactor, particularly the amount of energy delivered to cultured cells. The concise form of the solution simplifies the analysis of acoustic field problems.

Louw, Tobias; Whitney, Scott; Subramanian, Anu; Viljoen, Hendrik

2012-01-01

9

Internal force control with no object motion in compliant robotic grasps M. Malvezzi and D. Prattichizzo  

E-print Network

Internal force control with no object motion in compliant robotic grasps M. Malvezzi and D. Prattichizzo Abstract-- The control of internal forces is one of the key issues in grasping. When the robotic the structural conditions for the control of internal forces which do not involve any motion of the grasped

Siena, Università di

10

North Atlantic Multidecadal SST Oscillation: External forcing versus internal variability  

NASA Astrophysics Data System (ADS)

The Atlantic Multi-decadal Oscillation (AMO) depicts the swings of North Atlantic basin-wide sea surface temperature (SST) between warm and cold phases on a multi-decadal time scale. The 20th Century instrumental record indicates a relative cold period in the beginning of the 20th Century, a warm period in the 1940s and 50s, another cold period in the 1970s and 80s, followed by the recent warming period. These multi-decadal temperature swings coincide with an upward warming trend throughout the 20th Century. One of the central questions concerning these changes is whether they were caused by human activities, including aerosols and greenhouse gas forcing, or whether they reflect some combination between natural factors and human activity. Using both observations and CMIP3 model simulations, we argue that the overall changes are due to the combination of natural multidecadal variability and anthropogenic forcing. We also examine the regional surface temperature, precipitation, and atmospheric circulation features associated with the externally forced and internal North Atlantic SST multidecadal variability using both 20th Century observations and CMIP3 model simulations of the 20th, 21st, and pre-industrial forcing.

Ting, Mingfang; Kushnir, Yochanan; Li, Cuihua

2014-05-01

11

Atomic force microscopy to detect internal live processes in insects M. E. Dokukin,1  

E-print Network

Atomic force microscopy to detect internal live processes in insects M. E. Dokukin,1 N. V. Guz,1 S from internal live processes of insects. With a specially designed AFM stage to keep an insect motion partially restricted, the AFM can record internal oscillations on different parts of the insect. We

Sokolov, Igor

12

The Role of Internal Models in Motion Planning and Control: Evidence from Grip Force Adjustments during Movements  

E-print Network

The Role of Internal Models in Motion Planning and Control: Evidence from Grip Force Adjustments of an internal model of the motor apparatus in planning and controlling arm movements. In particular, we tested words: internal model; feedforward control; reaching movement; dynamics; grip force; load force; hand

Flanagan, Randy

13

Reflections on a Seminal Force in International Accounting  

ERIC Educational Resources Information Center

Accounting is a manifestation of several important environmental factors within a country, including economic, educational and political, and, as such, is evolutionary in accordance with those changing social structures. Because of the major impact that international accounting has had on countries' internal accounting systems, it is important to

Cascini, Karen T.

2007-01-01

14

Breeze-forced oscillations and strongly nonlinear tide-generated internal solitons .  

E-print Network

??[EN]The present thesis deals with observations of breeze-forced oscillations and modeling of strongly nonlinear tide-generated internal solitons. These two phenomena are of special interest owing (more)

Aguiar Gonzlez, M. Borja

2013-01-01

15

On the possible interaction between internal climate variability and forced climate change  

NASA Astrophysics Data System (ADS)

global warming hiatus does not necessarily mean a hiatus in anthropogenic greenhouse gas forcing and forced climate change (FCC). Here we show that both Atlantic Multidecadal Variability (AMV) and Pacific Decadal Oscillation (PDO) may cause fluctuations of the global mean surface air temperature (SAT) and hence alternately positive and negative trends on (inter)decadal time scales. However, the forced SAT change under a mean state due to greenhouse gas forcing does not depend on different phases of AMV and PDO, implying the effect of the FCC and internally generated climate variability can be linearly added up to the observed transient global mean SAT. On the other hand, the regional patterns of transient FCC do depend on the phases of the internal variability since the atmospheric and oceanic circulations can be affected by the different phases of the internal variability. Our results suggest a two-way interaction between internal variability and spatial patterns of FCC.

Lu, Jianhua; Hu, Aixue; Zeng, Zhen

2014-04-01

16

Attribution of Atlantic Multidecadal Variability to External Forcing, Internal Variability, and Weather Noise  

NASA Astrophysics Data System (ADS)

Detection of externally forced climate change and attribution of the causes of the externally forced and internally generated climate variability during the last century are the central scientific issues of current climate science and the subject of important controversies. This thesis systematically addresses fundamental problems in detection and attribution. A novel three-tier model ensemble strategy is developed and applied in the model world to address these issues. At the top tier, an ensemble of CGCMs with the same external forcing applied to each member is used to separate the results from each ensemble member into the externally forced and internally generated components. At the second tier, an ensemble of atmospheric GCMs (AGCM) with each member forced by the same SST, taken from a member of the CGCM ensemble, is used to separate the atmospheric variability in that CGCM member into SST-and-externally-forced and weather noise components. The third tier, uses an interactive ensemble version of the CGCM, in which the AGCM is replaced by an AGCM ensemble, so that atmospheric weather noise in the CGCM is suppressed. Controlled experiments forcing the interactive ensemble with the atmospheric noise diagnosed in the AGCM ensemble tier isolate the role of the weather noise in generating the internal SST variability found in the CGCM Ensemble tier. The strategy is employed to examine three important detection and attribution issues. The first is why the AGCM ensemble forced by observed SST does not simulate the observed 20th century sea level trends in the Indian Ocean. It has been suggested that this is because of an intrinsic failure of the AGCM Ensemble to correctly represent the SST forced response of the coupled system. The results show that the AGCM and CGCM ensembles are consistent with each other, and suggest that the failure to simulate the observed trends is due to model bias rather than coupling. Next, the spatial and temporal properties of the weather noise obtained from the CGCM and AGCM ensembles are examined in a preliminary fashion. This is the first attempt to document these properties. The temporal and spatial structures of the weather noise in the CGCM and AGCM simulations are very similar. The temporal structures of the noise spectra are white at timescales larger than approximately 5 months, although the noise is temporally non-Gaussian, while the spatial structures resemble those of major modes of observed climate variability. No change is detected between the statistical properties of the noise in the early and late 20th century. The Atlantic Multidecadal Variability (AMV) sea surface temperature is decomposed into externally forced and internally generated components using the CGCM ensemble, and the weather noise contribution to the internal component is isolated using the AGCM ensemble and interactive ensemble. The AMV has a strong contribution from the external 20th century forcing. The internal AMV variability is primary forced by the weather noise, but other sources of internal variability are also important. An important contribution to the internal AMV is associated with the internal variability of the oceanic Atlantic Meridional Overturning Circulation, and this contribution is distinct from the weather noise forced component.

Colfescu, Ioana

17

Motion Generation of the Capsubot Using Internal Force and Static Friction  

Microsoft Academic Search

In this paper, a capsule type robot is designed. The motion is described. The robot has no moving part outside its body, no legs, no wheel. Its motion is purely based on its internal force and friction with the environments. A four step motion pattern is proposed. A minimal energy solution is derived. A prototype capsule robot, consisting a plastic

Hongyi Li; Katsuhisa Furuta; Felix L. Chernousko

2006-01-01

18

Analysis of Korean Students' International Mobility by 2-D Model: Driving Force Factor and Directional Factor  

ERIC Educational Resources Information Center

The purpose of this study is to understand the dynamics of Korean students' international mobility to study abroad by using the 2-D Model. The first D, "the driving force factor," explains how and what components of the dissatisfaction with domestic higher education perceived by Korean students drives students' outward mobility to seek foreign

Park, Elisa L.

2009-01-01

19

Rapid generation of high-frequency internal waves beneath a wind and wave forced oceanic surface mixed layer  

E-print Network

Rapid generation of high-frequency internal waves beneath a wind and wave forced oceanic surface-frequency internal waves generated by Langmuir motions over stratified water may be an important source of turbulent the wind) generates high- frequency internal waves in the stratified fluid below. The internal waves evolve

Smith, Jerome A.

20

Analysis of squat and stoop dynamic liftings: muscle forces and internal spinal loads  

PubMed Central

Despite the well-recognized role of lifting in back injuries, the relative biomechanical merits of squat versus stoop lifting remain controversial. In vivo kinematics measurements and model studies are combined to estimate trunk muscle forces and internal spinal loads under dynamic squat and stoop lifts with and without load in hands. Measurements were performed on healthy subjects to collect segmental rotations during lifts needed as input data in subsequent model studies. The model accounted for nonlinear properties of the ligamentous spine, wrapping of thoracic extensor muscles to take curved paths in flexion and trunk dynamic characteristics (inertia and damping) while subject to measured kinematics and gravity/external loads. A dynamic kinematics-driven approach was employed accounting for the spinal synergy by simultaneous consideration of passive structures and muscle forces under given posture and loads. Results satisfied kinematics and dynamic equilibrium conditions at all levels and directions. Net moments, muscle forces at different levels, passive (muscle or ligamentous) forces and internal compression/shear forces were larger in stoop lifts than in squat ones. These were due to significantly larger thorax, lumbar and pelvis rotations in stoop lifts. For the relatively slow lifting tasks performed in this study with the lowering and lifting phases each lasting ?2s, the effect of inertia and damping was not, in general, important. Moreover, posterior shift in the position of the external load in stoop lift reaching the same lever arm with respect to the S1 as that in squat lift did not influence the conclusion of this study on the merits of squat lifts over stoop ones. Results, for the tasks considered, advocate squat lifting over stoop lifting as the technique of choice in reducing net moments, muscle forces and internal spinal loads (i.e., moment, compression and shear force). PMID:17103232

Bazrgari, Babak; Arjmand, Navid

2006-01-01

21

Perturbation analysis of internal balancing for lightly damped mechanical systems with gyroscopic and circulatory forces  

NASA Technical Reports Server (NTRS)

Approximate expressions are developed for internally balanced singular values corresponding to the modes of mechanical systems with gyroscopic forces, light damping, and small circulatory forces. A brief overview is first given of the balanced realization model reduction method, including a discussion of recent work. The models considered are defined, and a perturbation analysis is used to show that the modal representation becomes asymptotically balanced as damping reduces to zero. The approximate balanced singular values are calculated, and a simple example of a flexible, dual-spin spacecraft is given as an illustration of the results.

Blelloch, P. A.; Mingori, D. L.; Wei, J. D.

1987-01-01

22

Optical tweezers reveal force plateau and internal friction in PEG-induced DNA condensation.  

PubMed

The simplified artificial environments in which highly complex biological systems are studied do not represent the crowded, dense, salty, and dynamic environment inside the living cell. Consequently, it is important to investigate the effect of crowding agents on DNA. We used a dual-trap optical tweezers instrument to perform force spectroscopy experiments at pull speeds ranging from 0.3 to 270 ?m/s on single dsDNA molecules in the presence of poly(ethylene glycol) (PEG) and monovalent salt. PEG of sizes 1,500 and 4,000 Da condensed DNA, and force-extension data contained a force plateau at approximately 1 pN. The level of the force plateau increased with increasing pull speed. During slow pulling the dissipated work increased linearly with pull speed. The calculated friction coefficient did not depend on amount of DNA incorporated in the condensate, indicating internal friction is independent of the condensate size. PEG300 had no effect on the dsDNA force-extension curve. The force plateau implies that condensation induced by crowding agents resembles condensation induced by multivalent cations. PMID:24477280

Ojala, Heikki; Ziedaite, Gabija; Wallin, Anders E; Bamford, Dennis H; Hggstrm, Edward

2014-03-01

23

Analysis of squat and stoop dynamic liftings: muscle forces and internal spinal loads  

Microsoft Academic Search

Despite the well-recognized role of lifting in back injuries, the relative biomechanical merits of squat versus stoop lifting\\u000a remain controversial. In vivo kinematics measurements and model studies are combined to estimate trunk muscle forces and internal\\u000a spinal loads under dynamic squat and stoop lifts with and without load in hands. Measurements were performed on healthy subjects\\u000a to collect segmental rotations

Babak Bazrgari; Aboulfazl Shirazi-Adl; Navid Arjmand

2007-01-01

24

Global patterns of temperature response to climate forcings and internal climate oscillations  

NASA Astrophysics Data System (ADS)

Within the frame of the research of past climate behavior, substantial attention is often paid to the issue of attribution, i.e. identification of the factors responsible for observed variability and quantification of their effects. Here, we apply a regression-based time series analysis to identify and separate the contributions of various external and internal forcing factors to global temperature field, revealing the geographical structure of the connections between the forcings and temperature, and evaluating strength and statistical significance of these links. The explanatory variables considered represent external climate forcings (greenhouse gasses concentration, solar activity, major volcanic eruptions) as well as prominent internal oscillations in the climate system (Southern Oscillation, North Atlantic Oscillation, Atlantic Multidecadal Oscillation, Pacific Decadal Oscillation, Trans Polar Index-related circulation). Results for two datasets of gridded monthly temperature (20th Century Reanalysis and Berkeley Earth) are shown and compared, on a target period covering years 1901-2010. Along with visualization of the spatial patterns associated with contributions of individual forcing factors to the temperature field, their temporal variations (both seasonal and long-term) are also presented and discussed.

Mikovsk, Ji?; Pioft, Petr

2014-05-01

25

Binaries Traveling through a Gaseous Medium: Dynamical Drag Forces and Internal Torques  

NASA Astrophysics Data System (ADS)

Using time-dependent linear theory, we investigate the morphology of the gravitational wake induced by a binary, whose center of mass moves at velocity {\\boldsymbol {V}}_cm against a uniform background of gas. For simplicity, we assume that the components of the binary are on circular orbits about their common center of mass. The consequences of dynamical friction is twofold. First, gas dynamical friction may drag the center of mass of the binary and cause the binary to migrate. Second, drag forces also induce a braking torque, which causes the orbits of the components of the binary to shrink. We compute the drag forces acting on one component of the binary due to the gravitational interaction with its own wake. We show that the dynamical friction force responsible for decelerating the center of mass of the binary is smaller than it is in the point-mass case because of the loss of gravitational focusing. We show that the braking internal torque depends on the Mach numbers of each binary component about their center of mass, and also on the Mach number of the center of mass of the binary. In general, the internal torque decreases with increasing the velocity of the binary relative to the ambient gas cloud. However, this is not always the case. We also mention the relevance of our results to the period distribution of binaries.

Snchez-Salcedo, F. J.; Chametla, Raul O.

2014-10-01

26

Transport and mixing by internal waves in stellar interiors: effect of the Coriolis force  

E-print Network

We briefly recall the physical background of the transport of angular momentum and the mixing of chemicals inside stellar radiation zones and its importance for stellar evolution. Then, we describe its present modeling, its successes and its weaknesses. Next, we introduce the new theoretical developments that allow us to treat in a self-consistent way the effect of the Coriolis force on the low-frequencies internal waves and its consequences for the transport processes. This research is aimed at improving the modeling of stellar interiors in the perspective of future astero and helioseismology missions such as COROT and GOLF-NG.

S. Mathis; J. -P. Zahn

2007-06-16

27

International PV QA Task Force's Proposed Comparative Rating System for PV Modules: Preprint  

SciTech Connect

The International PV Quality Assurance Task Force is developing a rating system that provides comparative information about the relative durability of PV modules. Development of accelerated stress tests that can provide such comparative information is seen as a major step toward being able to predict PV module service life. This paper will provide details of the ongoing effort to determine the format of such an overall module rating system. The latest proposal is based on using three distinct climate zones as defined in IEC 60721-2-1 for two different mounting systems. Specific stresses beyond those used in the qualification tests are being developed for each of the selected climate zones.

Wohlgemuth, J.; Kurtz, S.

2014-10-01

28

The International Society for Bipolar Disorders (ISBD) Task Force Report on Antidepressant Use in Bipolar Disorders  

PubMed Central

Objective The risk-benefit profile of antidepressant medications in bipolar disorder is controversial. When conclusive evidence is lacking, expert consensus can guide treatment decisions. The International Society for Bipolar Disorders (ISBD) convened a task force to seek consensus recommendations on the use of antidepressants in bipolar disorders. Method An expert task force iteratively developed consensus through serial consensus-based revisions using the Delphi method. Initial survey items were based on systematic review of the literature. Subsequent surveys included new or reworded items and items that needed to be rerated. This process resulted in the final ISBD Task Force clinical recommendations on antidepressant use in bipolar disorder. Results There is striking incongruity between the wide use of and the weak evidence base for the efficacy and safety of antidepressant drugs in bipolar disorder. Few well-designed, long-term trials of prophylactic benefits have been conducted, and there is insufficient evidence for treatment benefits with antidepressants combined with mood stabilizers. A major concern is the risk for mood switch to hypomania, mania, and mixed states. Integrating the evidence and the experience of the task force members, a consensus was reached on 12 statements on the use of antidepressants in bipolar disorder. Conclusions Because of limited data, the task force could not make broad statements endorsing antidepressant use but acknowledged that individual bipolar patients may benefit from antidepressants. Regarding safety, serotonin reuptake inhibitors and bupropion may have lower rates of manic switch than tricyclic and tetracyclic antidepressants and norepinephrine-serotonin reuptake inhibitors. The frequency and severity of antidepressant-associated mood elevations appear to be greater in bipolar I than bipolar II disorder. Hence, in bipolar I patients antidepressants should be prescribed only as an adjunct to mood-stabilizing medications. PMID:24030475

Pacchiarotti, Isabella; Bond, David J.; Baldessarini, Ross J.; Nolen, Willem A.; Grunze, Heinz; Licht, Rasmus W.; Post, Robert M.; Berk, Michael; Goodwin, Guy M.; Sachs, Gary S.; Tondo, Leonardo; Findling, Robert L.; Youngstrom, Eric A.; Tohen, Mauricio; Undurraga, Juan; Gonzlez-Pinto, Ana; Goldberg, Joseph F.; Yildiz, Ay?egl; Altshuler, Lori L.; Calabrese, Joseph R.; Mitchell, Philip B.; Thase, Michael E.; Koukopoulos, Athanasios; Colom, Francesc; Frye, Mark A.; Malhi, Gin S.; Fountoulakis, Konstantinos N.; Vzquez, Gustavo; Perlis, Roy H.; Ketter, Terence A.; Cassidy, Frederick; Akiskal, Hagop; Azorin, Jean-Michel; Valent, Marc; Mazzei, Diego Hidalgo; Lafer, Beny; Kato, Tadafumi; Mazzarini, Lorenzo; Martnez-Aran, Anabel; Parker, Gordon; Souery, Daniel; zerdem, Ay?egl; McElroy, Susan L.; Girardi, Paolo; Bauer, Michael; Yatham, Lakshmi N.; Zarate, Carlos A.; Nierenberg, Andrew A.; Birmaher, Boris; Kanba, Shigenobu; El-Mallakh, Rif S.; Serretti, Alessandro; Rihmer, Zoltan; Young, Allan H.; Kotzalidis, Georgios D.; MacQueen, Glenda M.; Bowden, Charles L.; Ghaemi, S. Nassir; Lopez-Jaramillo, Carlos; Rybakowski, Janusz; Ha, Kyooseob; Perugi, Giulio; Kasper, Siegfried; Amsterdam, Jay D.; Hirschfeld, Robert M.; Kapczinski, Flvio; Vieta, Eduard

2014-01-01

29

Internally displaced "victims of armed conflict" in Colombia: the trajectory and trauma signature of forced migration.  

PubMed

While conflict-induced forced migration is a global phenomenon, the situation in Colombia, South America, is distinctive. Colombia has ranked either first or second in the number of internally displaced persons for 10 years, a consequence of decades of armed conflict compounded by high prevalence of drug trafficking. The displacement trajectory for displaced persons in Colombia proceeds through a sequence of stages: (1) pre-expulsion threats and vulnerability, (2) expulsion, (3) migration, (4) initial adaptation to relocation, (5) protracted resettlement (the end point for most forced migrants), and, rarely, (6) return to the community of origin. Trauma signature analysis, an evidence-based method that elucidates the physical and psychological consequences associated with exposures to harm and loss during disasters and complex emergencies, was used to identify the psychological risk factors and potentially traumatic events experienced by conflict-displaced persons in Colombia, stratified across the phases of displacement. Trauma and loss are experienced differentially throughout the pathway of displacement. PMID:25135775

Shultz, James M; Garfin, Dana Rose; Espinel, Zelde; Araya, Ricardo; Oquendo, Maria A; Wainberg, Milton L; Chaskel, Roberto; Gaviria, Silvia L; Ordez, Anna E; Espinola, Maria; Wilson, Fiona E; Muoz Garca, Natalia; Gmez Ceballos, Angela Milena; Garcia-Barcena, Yanira; Verdeli, Helen; Neria, Yuval

2014-10-01

30

Transducer for measuring the internal forces in the columns of a frame-wall reinforced concrete structure  

NASA Astrophysics Data System (ADS)

An internal force transducer (IFT) capable of accurately measuring the internal forces of the first story columns of a 1/5 scale model of a seven story frame-wall reinforced concrete structure was designed, developed, and applied in this structure under static and dynamic loading conditions. Although this IFT was developed specifically for research on this structure, the feasibility considerations, the development of design criteria, the design and fabrication considerations, and the calibration and installation methods reported herein have more general applicability.

Sause, R.; Bertero, V. V.

1983-05-01

31

An analytical model of the knee for estimation of internal forces during exercise  

Microsoft Academic Search

An analytical model of the knee joint was developed to estimate the forces at the knee during exercise. Muscle forces were estimated based upon electromyographic activities during exercise and during maximum voluntary isometric contraction (MVIC), physiological cross-sectional area (PCSA), muscle fiber length at contraction and the maximum force produced by an unit PCSA under MVIC. Tibiofemoral compressive force and cruciate

Naiquan Zheng; Glenn S. Fleisig; Rafael F. Escamilla; Steven W. Barrentine

1998-01-01

32

Report of a workshop on nuclear forces and nonproliferation Woodrow Wilson international center for scholars, Washington, DC October 28, 2010  

Microsoft Academic Search

A workshop sponsored by the Los Alamos National Laboratory in cooperation with the Woodrow Wilson International Center for Scholars was held at the Wilson Center in Washington, DC, on October 28, 2010. The workshop addressed evolving nuclear forces and their impacts on nonproliferation in the context of the new strategic environment, the Obama Administration's Nuclear Posture Review and the 2010

Pilat; Joseph F

2010-01-01

33

Probing Membrane Order and Topography in Supported Lipid Bilayers by Combined Polarized Total Internal Reflection Fluorescence-Atomic Force Microscopy  

PubMed Central

Determining the local structure, dynamics, and conformational requirements for protein-protein and protein-lipid interactions in membranes is critical to understanding biological processes ranging from signaling to the translocating and membranolytic action of antimicrobial peptides. We report here the application of a combined polarized total internal reflection fluorescence microscopy-in situ atomic force microscopy platform. This platform's ability to image membrane orientational order was demonstrated on DOPC/DSPC/cholesterol model membranes containing the fluorescent membrane probe, DiI-C20 or BODIPY-PC. Spatially resolved order parameters and fluorophore tilt angles extracted from the polarized total internal reflection fluorescence microscopy images were in good agreement with the topographical details resolved by insitu atomic force microscopy, portending use of this technique for high-resolution characterization of membrane domain structures and peptide-membrane interactions. PMID:19254557

Oreopoulos, John; Yip, Christopher M.

2009-01-01

34

Sea level changes in the North Atlantic by solar forcing and internal variability  

Microsoft Academic Search

Sea level change due to variations in the thermohaline structure of the North Atlantic has been calculated using a coupled ocean-atmosphere model of intermediate complexity (ECBilt). Two 1000-year simulations are made, one using a constant solar forcing and one using an estimate of historic variations in solar activity. In the solar forced simulation sea level variations are a proxy for

G. van der Schrier; S. Weber; S. Drijfhout

2002-01-01

35

Sea Level Changes In The North Atlantic By Solar Forcing and Internal Variability  

Microsoft Academic Search

Sea level change due to changes in the thermohaline structure of the North Atlantic has been calculated using a coupled ocean-atmosphere model of intermediate complexity (ECBilt). Two 1000-yr simulations are made, one using a constant solar forcing and one using an estimate of historic solar activity. In the solar forced simulation sea level variations are a proxy for climate variations.

G. van der Schrier; S. L. Weber; S. S. Drijfhout

2002-01-01

36

Analysis of object-stability and internal force in robotic contact tasks  

Microsoft Academic Search

The stability of an object manipulated by multiple robots (serial-link or wire-driven mechanisms) in contact tasks is investigated. We show that resultant force\\/moment applicable to the object through the contacts is represented as a polyhedral convex region in force\\/moment space. Then we propose a stability measure and a method of calculating it approximately by linear programming technique. We also present

Yusuke Maeda; Yasumichi Aiyama; Tamio Arai; Taiga Ozawa

1996-01-01

37

Forces Affecting the Improvement and Implementation of International Perspectives in Secondary Level Agricultural Programs in Texas. A Summary Report of Research. Department Information Bulletin 99-2.  

ERIC Educational Resources Information Center

A study analyzed the forces affecting improvement and implementation of international agricultural perspectives in secondary programs of agricultural science in Texas. A mail survey, based on force-field analysis, was used to determine the effect of 14 variables, including 3 that involved perceptions of the relevance, knowledge, and implementation

Bell, Larry G.

38

Heat transfer in a gray tube with forced convection, internal radiation and axial wall conduction  

NASA Technical Reports Server (NTRS)

A method of successive approximations is employed to solve the problem of heat transfer to a transparent gas flowing through a radiating-conducting tube with turbulent forced convection between the tube wall and the gas, and with energy generation in the wall. Emphasis is given to the effect of emissivity of the wall to the tube and gas temperature profiles.

Chung, B. T. F.; Thompson, J. E.

1983-01-01

39

EMPLOYMENT AND TRAINING POLICY IN A NEW ERA: THE IMPACT OF INTERNATIONAL AND INTERGOVERNMENTAL FORCES  

Microsoft Academic Search

Basic forces are influencing the American economy and significantly effecting employment and training policy. States need to take responsibility in solving the problems created by these trends. The implications of these trends-the technological revolution, internationalization of the American economy, and labor market and demographic changes-are examined. The first implication is that the United States cannot have effective economic policies unless

Ray Marshall

1987-01-01

40

The Role of Forcing and Internal Dynamics in explaining the 'Medieval Climate Anomaly'  

NASA Technical Reports Server (NTRS)

Proxy reconstructions suggest that peak global temperature during the past warm interval known as the Medieval Climate Anomaly (MCA, roughly 950-1250 AD) has been exceeded only during the most recent decades. To better understand the origin of this warm period, we use model simulations constrained by data assimilation establishing the spatial pattern of temperature changes that is most consistent with forcing estimates, model physics and the empirical information contained in paleoclimate proxy records. These numerical experiments demonstrate that the reconstructed spatial temperature pattern of the MCA can be explained by a simple thermodynamical response of the climate system to relatively weak changes in radiative forcing combined with a modification of the atmospheric circulation, displaying some similarities with the positive phase of the so-called Arctic Oscillation, and with northward shifts in the position of the Gulf Stream and Kuroshio currents. The mechanisms underlying the MCA are thus quite different from anthropogenic mechanisms responsible for modern global warming.

Goossee, Hugues; Crespin, Elisabeth; Dubinkina, Svetlana; Loutre, Marie-France; Mann, Michael E.; Renssen, Hans; Shindell, Drew

2012-01-01

41

Magnetic force microscopy/current contrast imaging: A new technique for internal current probing of ICs  

SciTech Connect

This invited paper describes recently reported work on the application of magnetic force microscopy (MFM) to image currents in IC conductors [1]. A computer model for MFM imaging of IC currents and experimental results demonstrating the ability to determine current direction and magnitude with a resolution of {approximately} 1 mA dc and {approximately} 1 {mu}A ac are presented. The physics of MFM signal generation and applications to current imaging and measurement are described.

Campbell, A.N.; Cole, E.I. Jr.; Dodd, B.A.; Anderson, R.E.

1993-09-01

42

Spatially and Temporally Synchronized Atomic Force and Total Internal Reflection Fluorescence Microscopy for Imaging and Manipulating Cells and Biomolecules  

PubMed Central

The atomic force microscope is a high-resolution scanning-probe instrument which has become an important tool for cellular and molecular biophysics in recent years but lacks the time resolution and functional specificities offered by fluorescence microscopic techniques. To exploit the advantages of both methods, here we developed a spatially and temporally synchronized total internal reflection fluorescence and atomic force microscope system. The instrument, which we hereby call STIRF-AFM, is a stage-scanning device in which the mechanical and optical axes are coaligned to achieve spatial synchrony. At each point of the scan the sample topography (atomic force microscope) and fluorescence (photon count or intensity) information are simultaneously recorded. The tool was tested and validated on various cellular (monolayer cells in which actin filaments and intermediate filaments were fluorescently labeled) and biomolecular (actin filaments and titin molecules) systems. We demonstrate that with the technique, correlated sample topography and fluorescence images can be recorded, soft biomolecular systems can be mechanically manipulated in a targeted fashion, and the fluorescence of mechanically stretched titin can be followed with high temporal resolution. PMID:16861276

Kellermayer, Mikls S. Z.; Karsai, rpd; Kengyel, Andrs; Nagy, Attila; Bianco, Pasquale; Huber, Tams; Kulcsr, gnes; Niedetzky, Csaba; Proksch, Roger; Grama, Lszl

2006-01-01

43

A pendulum-driven cart via internal force and static friction  

Microsoft Academic Search

In this paper, a pendulum driven cart is built using Lego robot parts. It consists of a cart with four passive wheels and a pendulum mounted on top of the cart. A DC motor is attached to the hinge joint between the cart and the pendulum which cart swing forward and backward. The cart motion is generated using its internal

Hongyi Li; Katsuhisa Furuta; Felix L. Chernousko

2005-01-01

44

Spinal muscle forces, internal loads and stability in standing under various postures and loads--application of kinematics-based algorithm.  

PubMed

This work aimed to evaluate trunk muscle forces, internal loads and stability margin under some simulated standing postures, with and without external loads, using a nonlinear finite element model of the T1-S1 spine with realistic nonlinear load-displacement properties. A novel kinematics-based algorithm was applied that exploited a set of spinal sagittal rotations, initially calculated to minimize balancing moments, to solve the redundant active-passive system. The loads consisted of upper body gravity distributed along the spine with or without 200 N held in the hands, either in the front of the body or on the sides. Nonlinear and linear stability/perturbation analyses at deformed, stressed configurations with a linear stiffness-force relationship for muscles identified the system stability and critical muscle stiffness coefficient. Predictions were in good agreement with reported measurements of posture, muscle EMG and intradiscal pressure. Minimal changes in posture (posterior pelvic tilt and lumbar flattening) substantially influenced muscle forces, internal loads and stability margin. Addition of 200 N load in front of the body markedly increased the system stability, global muscle forces, and internal loads, which reached anterior shear and compression forces of approximately 500 N and approximately 1,200 N, respectively, at lower lumbar levels. Co-activation in abdominal muscles (up to 3% maximum force) substantially increased extensor muscle forces, internal loads and stability margin, allowing a smaller critical muscle coefficient. A tradeoff existed between lower internal loads in passive tissues and higher stability margins, as both increased with greater muscle activation. The strength of the proposed model is in accounting for the synergy by simultaneous consideration of passive structure and muscle forces under applied postures and loads. PMID:15452703

Shirazi-Adl, A; El-Rich, M; Pop, D G; Parnianpour, M

2005-05-01

45

A spectral fictitious domain method with internal forcing for solving elliptic PDEs  

NASA Astrophysics Data System (ADS)

A fictitious domain method is presented for solving elliptic partial differential equations using Galerkin spectral approximation. The fictitious domain approach consists in immersing the original domain into a larger and geometrically simpler one in order to avoid the use of boundary fitted or unstructured meshes. In the present study, boundary constraints are enforced using Lagrange multipliers and the novel aspect is that the Lagrange multipliers are associated with smooth forcing functions, compactly supported inside the fictitious domain. This allows the accuracy of the spectral method to be preserved, unlike the classical discrete Lagrange multipliers method, in which the forcing is defined on the boundaries. In order to have a robust and efficient method, equations for the Lagrange multipliers are solved directly with an influence matrix technique. Using a Fourier-Chebyshev approximation, the high-order accuracy of the method is demonstrated on one- and two-dimensional elliptic problems of second- and fourth-order. The principle of the method is general and can be applied to solve elliptic problems using any high order variational approximation.

Buffat, Marc; Le Penven, Lionel

2011-04-01

46

New internal structure of spider dragline silk revealed by atomic force microscopy.  

PubMed Central

Atomic force microscopy was used to study the three-dimensional nanometer-scale structure of the dragline silk of Nephila clavipes from microtomed sections of the silk. Contrary to a previously proposed model of randomly distributed protein crystallites interspersed in amorphous regions, a highly organized skin-core structure of the fiber was observed. The skin appeared to be thin with no discernible distinct features. The core consists of pleated fibril-like structures, which are arranged in two concentric cylinders. Upon stretching, the pleats were smoothed out substantially. The mechanical properties of spider silk can quite straightforwardly be related to the newly observed structures. Images FIGURE 1 FIGURE 2 FIGURE 3 FIGURE 4 PMID:8038392

Li, S F; McGhie, A J; Tang, S L

1994-01-01

47

Driving force transmission mechanism using a timing belt for an internal combustion engine  

SciTech Connect

A driving force transmission mechanism is described comprising: a timing pulley having teeth, each of the teeth having a width perpendicular to a direction of movement of the teeth; and a timing belt engaging the timing pulley, the timing belt having teeth, each of the timing belt teeth having a width perpendicular to a direction of movement of the timing belt teeth; a width of the timing belt not being larger that a width of the timing pulley; the width of the teeth of the timing belt at dedendums of the teeth being larger than a width of engagement of the teeth of the timing belt with the teeth of the timing pulley; at least one of width end portions of the teeth of the timing pulley and width end portions of the teeth of the timing belt being cut out so that width end portions of the teeth of the timing belt at dedendums of the timing belt do not contact the teeth of the timing pulley.

Abe, S.

1987-11-24

48

International confederation for cleft lip and palate and related craniofacial anomalies task force report: beyond eurocleft.  

PubMed

The assigned objective for the Task Force Beyond Eurocleft was "to make recommendations for initiations of local and/or participation in multi-national cleft outcome studies and consist of individuals from the European experience with cleft outcome studies (Scandcleft, Eurocleft) and those who have initiated, or intend to initiate, similar studies in other geographical areas." By May 2013 the Task Force (TF) consisted of 183 members from 59 countries. It was agreed that this initiative should be truly global and include all cleft specialties as well as representatives from cleft support groups in recognition of the huge commitment for improving cleft care worldwide. The vision for this group is to build a dynamic, well-functioning TF that will work globally and be multidisciplinary with inclusive and respectful behavior to improve care for all individuals born with cleft lip and/or palate. As there is a large diversity in needs and interest in the group a range of parallel approaches would be required depending on the experience, resources, and challenges of regions, teams, and individuals. Important ideas for future work were: (1) Work on a global survey of access, existing outcome studies, current collaborations, and lessons learned. (2) Work towards the creation of a lasting, living resource for newcomers to intercenter collaboration that is kept fresh with new reports, copies of relevant publications, model grant applications, and a list of volunteers with the right experience to provide support and guidance for new initiatives. (3) Develop simple online training modules to provide information about the benefits and principles of multidisciplinary care, collaborative data collection and auditing short and longer-term outcomes. (4) Establish subgroups that will work within all regions of the world with regional and national leaders identified. An evaluation of current standards of care should be undertaken and country/region specific remedies to optimize treatment outcome suggested. (5) Reach agreement on minimum standards of care, minimum record collection, and reach consensus on simple outcome measures in all disciplines. This should include all cleft types and all ages. These standards could be used to encourage governments to fund multidisciplinary care. (6) Teams will be encouraged to start and continue recordkeeping using simple and agreed protocols, according to agreed standards of minimum records and later share their data with other teams and then, embark on outcome studies. (7) Teams already active in research should: Create a register for cleft professionals and teams to reach agreement of contemporary and comprehensive multidisciplinary outcome measures, explore the possibilities using modern technology and plan large multi-national studies. A patient/parent centered data collection should always be included. These studies need funding. One task could also be exploring whether health care at a distance could be initiated using new technology. PMID:25244656

Semb, Gunvor

2014-11-01

49

Quartic canonical force field in curvilinear internal coordinates for XY3 (D3h) molecules. The case of the BH3 molecule.  

PubMed

Using the canonical force field theory, expressions of quadratic, cubic, and quartic canonical force constants are obtained for XY3 (D3h) molecules in curvilinear redundant coordinates, i.e., simple valence internal coordinates (VICs), in terms of force constants in normal coordinates and in independent symmetry coordinates. To carry out this task, it was previously necessary to obtain for the first time the non-linear redundancy relation and the corresponding orthogonal projection onto the pure vibrational manifold for XY3 (D3h) molecules corresponding to a set of seven VICs. As an application, the quartic canonical force field in curvilinear redundant internal coordinates of BH3 is determined from ab initio force fields in normal coordinates calculated at the coupled-cluster singles and doubles level with perturbative treatment of the triples in conjunction with a triple- and quadruple-? size basis set. This anharmonic force field so obtained for the borane molecule, and in general for XY3 (D3h) molecules, is uniquely defined (therefore in an unambiguous form) and depending on the same number of parameters, i.e., force constants, when independent coordinates (natural or symmetry) are used in its description. PMID:24842323

Rdenas, Consuelo Rosales; Quesada, Juana Vzquez; Torres, Emilio Martnez; Gonzlez, Juan Jess Lpez

2014-06-01

50

Eruption triggering of giant magma bodies by internal versus external forcing: A rhyolite-MELTS study  

NASA Astrophysics Data System (ADS)

Silicic volcanism, particularly supereruptions, raises questions about the mechanisms by which magma bodies destabilize and erupt. Are external events necessary to initiate an eruption of a large silicic system, or is possible for internal processes (crystallization, volatile exsolution) to destabilize a system and drive it to erupt? If external triggers are critically important to prompting eruption, are all felsic magma bodies equally prone to erupt? To respond to these questions, we use rhyolite-MELTS (Gualda et al. 2012) to investigate the pre-eruptive chemical evolution and the resultant changes to physical properties of giant (super-eruptive) felsic magma bodies. Simulations are conducted using pumice and glass compositions from the Peach Spring (Southwestern USA) and the Bishop (California USA) Tuffs, two giant high-silica rhyolite deposits. In our simulations, we vary initial pressure (150-350 MPa in 50 MPa intervals), volatile content (initial water ranging from 1-7 wt. %), mode of crystallization (equilibrium vs. fractional), and rheology of the magma reservoir (isobaric vs. isochoric vs. transitional). We run simulations through as much of the crystallization interval as possible, but focus on the first ~50 wt. % crystallization, most relevant for volcanic systems. In all simulations, we observe near-invariant behavior when the system becomes saturated in quartz, two feldspars and a fluid phase, from which point crystallization is essentially isothermal. Prior to the near-invariant, crystallization leads to gradual changes in bulk properties (e.g., < 1% volume decrease over 50 C), which effectively results in modest pressure changes within the magma body (i.e., ~10 MPa). Upon reaching the near-invariant, the bulk properties change abruptly (e.g., > 5% volume increase in 0.1 C), causing significant overpressurization of the magma body. The magnitude of this overpressurization (i.e. 10s to 100s of MPa depending on system conditions) is sufficient to exceed the yield strength of the country rocks, effectively making eruption possible independent of any external triggers. Our simulations reveal that the Peach Spring and Bishop Tuff magmatic systems represent two contrasting types of behavior. In the Bishop case, only ~5-25 wt.% of crystallization over a short temperature interval (~30 C cooling) is needed to reach near-invariant behavior, making it plausible that crystallization led to eruption without external triggers. This is consistent with the lack of evidence for interaction of Bishop magma with mafic magmas. In the Peach Spring case, 30-70 wt. % crystallization over a much longer temperature interval (~60-130 C cooling) is needed for the system to reach the near-invariant. Given that Peach Spring pumice and fiamme are characterized by <30 wt. % crystals, it seems unlikely that crystallization alone led to eruption, suggesting the action of an external trigger in promoting eruption. This is consistent with evidence for significant heating and mush remobilization preserved in intracaldera Peach Spring rocks. Our results show that phase-equilibria constrains whether a magma system is likely to destabilize itself and erupt as a result of overpressurization by closed-system crystallization and volatile exsolution.

Carley, T. L.; Gualda, G. A.; Ghiorso, M. S.; Miller, C. F.

2012-12-01

51

Computation of the internal forces in cilia: application to ciliary motion, the effects of viscosity, and cilia interactions.  

PubMed Central

This paper presents a simple and reasonable method for generating a phenomenological model of the internal mechanism of cilia. The model uses a relatively small number of parameters whose values can be obtained by fitting to ciliary beat shapes. Here, we use beat patterns observed in Paramecium. The forces that generate these beats are computed and fit to a simple functional form called the "engine." This engine is incorporated into a recently developed hydrodynamic model that accounts for interactions between neighboring cilia and between the cilia and the surface from which they emerge. The model results are compared to data on ciliary beat patterns of Paramecium obtained under conditions where the beats are two-dimensional. Many essential features of the motion, including several properties that are not built in explicitly, are shown to be captured. In particular, the model displays a realistic change in beat pattern and frequency in response to increased viscosity and to the presence of neighboring cilia in configurations such as rows of cilia and two-dimensional arrays of cilia. We found that when two adjacent model cilia start beating at different phases they become synchronized within several beat periods, as observed in experiments where two flagella are brought into close proximity. Furthermore, examination of various multiciliary configurations shows that an approximately antiplectic wave pattern evolves autonomously. This modeling evidence supports earlier conjectures that metachronism may occur, at least partially, as a self-organized phenomenon due to hydrodynamic interactions between neighboring cilia. PMID:9545031

Gueron, S; Levit-Gurevich, K

1998-01-01

52

32 CFR 536.113 - Assistance to foreign forces for claims arising under international agreements (as to claims...  

Code of Federal Regulations, 2010 CFR

...arising under international agreements (as to claims arising in...Cognizable Under International Agreements 536.113 Assistance...arising under international agreements (as to claims arising in...from activities of members of NATO, Partnership for...

2010-07-01

53

A review of a method for dynamic load distribution, dynamical modeling, and explicit internal force control when two manipulators mutually lift and transport a rigid body object  

SciTech Connect

The paper reviews a method for modeling and controlling two serial link manipulators which mutually lift and transport a rigid body object in a three dimensional workspace. A new vector variable is introduced which parameterizes the internal contact force controlled degrees of freedom. A technique for dynamically distributing the payload between the manipulators is suggested which yields a family of solutions for the contact forces and torques the manipulators impart to the object. A set of rigid body kinematic constraints which restrict the values of the joint velocities of both manipulators is derived. A rigid body dynamical model for the closed chain system is first developed in the joint space. The model is obtained by generalizing the previous methods for deriving the model. The joint velocity and acceleration variables in the model are expressed in terms of independent pseudovariables. The pseudospace model is transformed to obtain reduced order equations of motion and a separate set of equations governing the internal components of the contact forces and torques. A theoretic control architecture is suggested which explicitly decouples the two sets of equations comprising the model. The controller enables the designer to develop independent, non-interacting control laws for the position control and internal force control of the system.

Unseren, M.A.

1997-04-20

54

Subthalamic nucleus and internal globus pallidus scale with the rate of change of force production in humans  

Microsoft Academic Search

The basal ganglia, motor cortex, and cerebellum have been implicated as a circuit that codes for movement velocity. Since movement velocity covaries with the magnitude of force exerted and previous studies have shown that similar regions scale in activation for velocity and force, the scaling of neuronal activity with movement velocity could be due to the force exerted. The present

David E. Vaillancourt; Mary A. Mayka; Keith R. Thulborn; Daniel M. Corcos

2004-01-01

55

Assessment of forced and internal variability in the AMO through analyses of SST data from CMIP5 historical simulations and observations  

NASA Astrophysics Data System (ADS)

The Atlantic Multidecadal Oscillation (AMO) is a mode of North Atlantic sea surface temperature (SST) variability that has substantial impacts on Northern Hemisphere precipitation and temperature patterns, as well as Atlantic hurricane activity. Climate models and paleoclimate data suggest that the warm AMO phase can enhance drought in the American mid- and southwest, increase rainfall intensity and amounts in North Eastern Brazil and the African Sahel region, and increase the number of severe Atlantic hurricanes. While models and instrumental data provide some support for the AMO as an internal climate ';oscillation', questions remain regarding the proportion of AMO variability resulting from internal and external forcing, and more specifically, how much of the recent (i.e. late 20th century) north Atlantic warming is anthropogenically forced. Several studies have addressed these issues and proposed various methods for diagnosing the AMO using historical climate model simulations (e.g. from CMIP3) and instrumental data. Here we present results from analyses of the North Atlantic region in historical simulations from Climate Model Intercomparison Project 5 (CMIP5). Our approach involves (1) analyzing a grand ensemble mean based on averaging realizations of all available models, such that random, internal variability components cancel and only a forced component remains; (2) for all models with at least four realizations, estimating a forced component by averaging multiple realizations and estimating internal variability components from the residual series of individual realizations and (3) analyzing control simulations for the corresponding models to assess whether or not there is evidence of enhanced AMO-like internal variability.

Steinman, B. A.; Mann, M. E.; Miller, S. K.; Emanuel, K.

2013-12-01

56

Organization of the United States International Communications Industry. Appendix. Report of the Panel on Satellites and Other Long-Haul Transmission Modes of the National Academy of Engineering. President's Task Force on Communications Policy. Staff Paper Two.  

ERIC Educational Resources Information Center

A staff paper to the President's Task Force on Communications Policy reviews the organization of the American international communications industries and recommends a consolidation of the competing international carriers. Particularly emphasized is the competition and division of ownership between the two technologies involved in international

Rostow, Eugene V.

57

THE IMPACT OF SAGITTAL PLANE HIP POSITION ON ISOMETRIC FORCE OF HIP EXTERNAL ROTATOR AND INTERNAL ROTATOR MUSCLES IN HEALTHY YOUNG ADULTS  

PubMed Central

Purpose/Background: Hip external rotator (ER) and internal rotator (IR) muscle weakness is theorized to be associated with lower extremity injury in athletes including knee ligament tears and patellofemoral pain. Previous studies investigating hip musculature strength have utilized various sagittal plane hip positions for testing. The relationship between results at these different positions is unknown. Methods: Eighty healthy, pain?free young adults participated in the study: 40 female, mean age 22.90 ( 2.32) years, and 40 male, mean age 23.50 ( 2.15) years. Peak isometric torque of bilateral hip ER and IR were tested at 90 and 0 of hip flexion with an instrumented dynamometer. Peak muscle forces were calculated. Peak forces were normalized by body mass. Mean normalized force was calculated for dominant and non?dominant limbs for ER and IR in both positions. Male and female data were analyzed separately with paired t?tests (2?tailed). Reference values for average muscle force and torque were calculated for dominant and non?dominant limbs for both hip positions. Results: Hip IR normalized peak force was greater at 90 compared to 0 flexion position bilaterally in both genders (p < .01). Hip ER normalized peak force was greater at 90 compared to 0 flexion in dominant limbs of both genders and in non?dominant limbs of males (p < .01). Non?dominant hip ER normalized force in females was greater at 90 versus 0 flexion; however, it was not significant (p = .092). Post hoc analysis of normalized average force (average over 5?second contraction) yielded similar results. Conclusion: Clinicians and researchers should use consistent positioning for testing of hip ER and IR strength. This will improve certainty of determining if a patients strength has changed or if differences between groups are present. Reference values reported will be useful in order to determine if weakness is present and to set goals, particularly in cases of bilateral involvement. Level of Evidence: 2b PMID:24567856

Wong, Anson L. K.; Rickards, Cory

2014-01-01

58

Modulation of internal model formation during force field-induced motor learning by anodal transcranial direct current stimulation of primary motor cortex.  

PubMed

Human subjects can quickly adapt and maintain performance of arm reaching when experiencing novel physical environments such as robot-induced velocity-dependent force fields. Using anodal transcranial direct current stimulation (tDCS) this study showed that the primary motor cortex may play a role in motor adaptation of this sort. Subjects performed arm reaching movement trials in three phases: in a null force field (baseline), in a velocity-dependent force field (adaptation; 25 N s m(-1)) and once again in a null force field (de-adaptation). Active or sham tDCS was directed to the motor cortex representation of biceps brachii muscle during the adaptation phase of the motor learning protocol. During the adaptation phase, the global error in arm reaching (summed error from an ideal trajectory) was similar in both tDCS conditions. However, active tDCS induced a significantly greater global reaching (overshoot) error during the early stage of de-adaptation compared to the sham tDCS condition. The overshoot error may be representative of the development of a greater predictive movement to overcome the expected imposed force. An estimate of the predictive, initial movement trajectory (signed error in the first 150 ms of movement) was significantly augmented during the adaptation phase with active tDCS compared to sham tDCS. Furthermore, this increase was linearly related to the change of the overshoot summed error in the de-adaptation process. Together the results suggest that anodal tDCS augments the development of an internal model of the novel adapted movement and suggests that the primary motor cortex is involved in adaptation of reaching movements of healthy human subjects. PMID:19403605

Hunter, Timothy; Sacco, Paul; Nitsche, Michael A; Turner, Duncan L

2009-06-15

59

Policy and Practice Implications of the Program for International Student Assessment (PISA) 2000. Report of the International Reading Association PISA Task Force.  

ERIC Educational Resources Information Center

The Program for International Student Assessment (PISA) is a study of comparisons. Subjects, 15-year-old students from 32 participating countries, were compared in their abilities to "use literacy knowledge and skills to meet real-life challenges," as assessed on a two-hour, paper-and-pencil test. Students also responded to a questionnaire related

Topping, Keith; Valtin, Renate; Roller, Cathy; Brozo, William; Dionisio, M. Lourdes

60

PREFACE: NC-AFM 2006: Proceedings of the 9th International Conference on Non-contact Atomic Force Microscopy  

Microsoft Academic Search

The advent of scanning probe microscopy (SPM) in the 1980s has significantly promoted nanoscience and nanotechnology. In particular, non-contact atomic force microscopy (NC-AFM), one of the SPM family, has unique capabilities with high spatial resolution for nanoscale measurements in vacuum, air and liquids. In the last decade we have witnessed the rapid progress of NC-AFM with improved performance and increasing

Masahiko Tomitori; Hiroshi Onishi

2007-01-01

61

NC-AFM 2006: Proceedings of the 9th International Conference on Non-contact Atomic Force Microscopy  

Microsoft Academic Search

The advent of scanning probe microscopy (SPM) in the 1980s has significantly promoted nanoscience and nanotechnology. In particular, non-contact atomic force microscopy (NC-AFM), one of the SPM family, has unique capabilities with high spatial resolution for nanoscale measurements in vacuum, air and liquids. In the last decade we have witnessed the rapid progress of NC-AFM with improved performance and increasing

2007-01-01

62

Can International Large-Scale Assessments Inform a Global Learning Goal? Insights from the Learning Metrics Task Force  

ERIC Educational Resources Information Center

In recent years, the global community has developed a range of initiatives to inform the post-2015 global development agenda. In the education community, International Large-Scale Assessments (ILSAs) have an important role to play in advancing a global shift in focus to access plus learning. However, there are a number of other assessment tools

Winthrop, Rebecca; Simons, Kate Anderson

2013-01-01

63

Speaker-External versus Speaker-Internal Forces on Utterance Form: Do Cognitive Demands Override Threats to Referential Success?  

ERIC Educational Resources Information Center

To what extent do speaker-external communicative pressures versus speaker-internal cognitive pressures affect utterance form? Four experiments measured speakers' references to privately known (i.e., privileged) objects when naming mutually known (i.e., common ground) objects. Although speaker-external communicative pressures demanded that speakers

Lane, Liane Wardlow; Ferreira, Victor S.

2008-01-01

64

Armed conflict, homonegativity, and forced internal displacement: Implications for HIV among Colombian gay, bisexual, and transgender individuals  

PubMed Central

Colombia has endured six decades of civil unrest, population displacement, and violence. We examined the relationships of contextual conditions, displacement, and HIV among gay, bisexual, and transgender individuals in Bogot, Colombia. Nineteen key informants provided information about internal displacement of sexual minorities. Life history interviews were conducted with 42 participants aged 18 to 48 years, and included questions about displacement experiences, sexual behaviour, life prior to displacement, and participants economic and social situation in Bogot. The interplay of a variety of factorsincluding internal conflict and violence, homonegativity and social cleansing, gender and sexual identity, and povertystrongly shaped the varied experiences of displacement. Migration, sexual violence, exchange sex, and low rates of HIV testing were risk factors that increased vulnerability for HIV in this displaced sample. Although displacement and HIV in Colombia are major problems, both are understudied. PMID:23586420

Reisen, Carol A.; Bianchi, Fernanda T.; Gonzales, Felisa A.; Betancourt, Fabin; Aguilar, Marcela; Poppen, Paul J.

2013-01-01

65

Armed conflict, homonegativity and forced internal displacement: implications for HIV among Colombian gay, bisexual and transgender individuals.  

PubMed

Colombia has endured six decades of civil unrest, population displacement and violence. We examined the relationships between contextual conditions, displacement and HIV among gay, bisexual and transgender individuals in Bogot, Colombia. A total of 19 key informants provided information about internal displacement of sexual minorities. Life-history interviews were conducted with 42 participants aged 18 to 48 years and included questions about displacement experiences, sexual behaviour, life prior to displacement and participants' economic and social situation in Bogot. The interplay of a variety of factors - including internal conflict and violence, homonegativity and 'social cleansing', gender and sexual identity and poverty - strongly shaped the varied experiences of displacement. Migration, sexual violence, exchange sex and low rates of HIV testing were risk factors that increased vulnerability for HIV in this displaced sample. Although displacement and HIV in Colombia are major problems, both are understudied. PMID:23586420

Zea, Maria Cecilia; Reisen, Carol A; Bianchi, Fernanda T; Gonzales, Felisa A; Betancourt, Fabin; Aguilar, Marcela; Poppen, Paul J

2013-01-01

66

Electronics goes halogen-free: international driving forces and the availability and potential of halogen-free alternatives  

Microsoft Academic Search

The electronics and electrical industry and their suppliers are facing an increasing need to find halogen-free alternatives to flame retardancy in their products due to legislative actions and market pressure. In order to support development of corporate actions, The International project on Flame Retardancy in Electronics-Conceptual Study, has been carried out by IVF in co-operation with 12 major European and

C. G. Bergendahl

2000-01-01

67

Partitioning of knee joint internal forces in gait is dictated by the knee adduction angle and not by the knee adduction moment.  

PubMed

Medial knee osteoarthritis is a debilitating disease. Surgical and conservative interventions are performed to manage its progression via reduction of load on the medial compartment or equivalently its surrogate measure, the external adduction moment. However, some studies have questioned a correlation between the medial load and adduction moment. Using a musculoskeletal model of the lower extremity driven by kinematics-kinetics of asymptomatic subjects at gait midstance, we aim here to quantify the relative effects of changes in the knee adduction angle versus changes in the adduction moment on the joint response and medial/lateral load partitioning. The reference adduction rotation of 1.6 is altered by 1.5 to 3.1 and 0.1 or the knee reference adduction moment of 17Nm is varied by 50% to 25.5Nm and 8.5Nm. Quadriceps, hamstrings and tibiofemoral contact forces substantially increased as adduction angle dropped and diminished as it increased. The medial/lateral ratio of contact forces slightly altered by changes in the adduction moment but a larger adduction rotation hugely increased this ratio from 8.8 to a 90 while in contrast a smaller adduction rotation yielded a more uniform distribution. If the aim in an intervention is to diminish the medial contact force and medial/lateral load ratio, a drop of 1.5 in adduction angle is much more effective (causing respectively 12% and 80% decreases) than a reduction of 50% in the adduction moment (causing respectively 4% and 13% decreases). Substantial role of changes in adduction angle is due to the associated alterations in joint nonlinear passive resistance. These findings explain the poor correlation between knee adduction moment and tibiofemoral compartment loading during gait suggesting that the internal load partitioning is dictated by the joint adduction angle. PMID:24636718

Adouni, M; Shirazi-Adl, A

2014-05-01

68

Turbofan forced mixer-nozzle internal flowfield. Volume 3: A computer code for 3-D mixing in axisymmetric nozzles  

NASA Technical Reports Server (NTRS)

A finite difference method is developed for making detailed predictions of three dimensional subsonic turbulent flow in turbofan lobe mixers. The governing equations are solved by a forward-marching solution procedure which corrects an inviscid potential flow solution for viscous and thermal effects, secondary flows, total pressure distortion and losses, internal flow blockage and pressure drop. Test calculations for a turbulent coaxial jet flow verify that the turbulence model performs satisfactorily for this relatively simple flow. Lobe mixer flows are presented for two geometries typical of current mixer design. These calculations included both hot and cold flow conditions, and both matched and mismatched Mach number and total pressure in the fan and turbine streams.

Kreskovsky, J. P.; Briley, W. R.; Mcdonald, H.

1982-01-01

69

A magnesium-induced RNA conformational switch at the internal ribosome entry site of hepatitis C virus genome visualized by atomic force microscopy.  

PubMed

The 5' untranslated region of hepatitis C virus (HCV) genomic RNA contains an internal ribosome entry site (IRES) element, composed of domains II-IV, which is required for cap-independent translation initiation. Little information on the 3D structure of the whole functional HCV IRES is still available. Here, we use atomic force microscopy to visualize the HCV IRES conformation in its natural sequence context, which includes the upstream domain I and the essential, downstream domains V and VI. The 574 nt-long molecule analyzed underwent an unexpected, Mg(2+)-induced switch between two alternative conformations: from 'open', elongated morphologies at 0-2 mM Mg(2+) concentration to a 'closed', comma-shaped conformation at 4-6 mM Mg(2+). This sharp transition, confirmed by gel-shift analysis and partial RNase T1 cleavage, was hindered by the microRNA miR-122. The comma-shaped IRES-574 molecules visualized at 4-6 mM Mg(2+) in the absence of miR-122 showed two arms. Our data support that the first arm would contain domain III, while the second one would be composed of domains (I-II)+(V-VI) thanks to a long-range RNA interaction between the I-II spacer and the basal region of domain VI. This reinforces the previously described structural continuity between the HCV IRES and its flanking domains I, V and VI. PMID:25510496

Garca-Sacristn, Ana; Moreno, Miguel; Ariza-Mateos, Ascensin; Lpez-Camacho, Elena; Judenes, Rosa M; Vzquez, Luis; Gmez, Jordi; Martn-Gago, Jos ngel; Briones, Carlos

2015-01-01

70

A magnesium-induced RNA conformational switch at the internal ribosome entry site of hepatitis C virus genome visualized by atomic force microscopy  

PubMed Central

The 5? untranslated region of hepatitis C virus (HCV) genomic RNA contains an internal ribosome entry site (IRES) element, composed of domains IIIV, which is required for cap-independent translation initiation. Little information on the 3D structure of the whole functional HCV IRES is still available. Here, we use atomic force microscopy to visualize the HCV IRES conformation in its natural sequence context, which includes the upstream domain I and the essential, downstream domains V and VI. The 574 nt-long molecule analyzed underwent an unexpected, Mg2+-induced switch between two alternative conformations: from open, elongated morphologies at 02 mM Mg2+ concentration to a closed, comma-shaped conformation at 46 mM Mg2+. This sharp transition, confirmed by gel-shift analysis and partial RNase T1 cleavage, was hindered by the microRNA miR-122. The comma-shaped IRES-574 molecules visualized at 46 mM Mg2+ in the absence of miR-122 showed two arms. Our data support that the first arm would contain domain III, while the second one would be composed of domains (III)+(VVI) thanks to a long-range RNA interaction between the I-II spacer and the basal region of domain VI. This reinforces the previously described structural continuity between the HCV IRES and its flanking domains I, V and VI. PMID:25510496

Garca-Sacristn, Ana; Moreno, Miguel; Ariza-Mateos, Ascensin; Lpez-Camacho, Elena; Judenes, Rosa M.; Vzquez, Luis; Gmez, Jordi; Martn-Gago, Jos ngel; Briones, Carlos

2015-01-01

71

A review of a method for dynamic load distribution, dynamic modeling, and explicit internal force control when two serial link manipulators mutually lift and transport a rigid body object  

SciTech Connect

The report reviews a method for modeling and controlling two serial link manipulators which mutually lift and transport a rigid body object in a three dimensional workspace. A new vector variable is introduced which parameterizes the internal contact force controlled degrees of freedom. A technique for dynamically distributing the payload between the manipulators is suggested which yields a family of solutions for the contact forces and torques the manipulators impart to the object. A set of rigid body kinematic constraints which restricts the values of the joint velocities of both manipulators is derived. A rigid body dynamical model for the closed chain system is first developed in the joint space. The model is obtained by generalizing the previous methods for deriving the model. The joint velocity and acceleration variables in the model are expressed in terms of independent pseudovariables. The pseudospace model is transformed to obtain reduced order equations of motion and a separate set of equations governing the internal components of the contact forces and torques. A theoretic control architecture is suggested which explicitly decouples the two sets of equations comprising the model. The controller enables the designer to develop independent, non-interacting control laws for the position control and internal force control of the system.

Unseren, M.A.

1997-09-01

72

Drag force acting on a neuromast in the fish lateral line trunk canal. I. Numerical modelling of externalinternal flow coupling  

PubMed Central

Fishes use a complex, multi-branched, mechanoreceptive organ called the lateral line to detect the motion of water in their immediate surroundings. This study is concerned with a subset of that organ referred to as the lateral line trunk canal (LLTC). The LLTC consists of a long tube no more than a few millimetres in diameter embedded immediately under the skin of the fish on each side of its body. In most fishes, pore-like openings are regularly distributed along the LLTC, and a minute sensor enveloped in a gelatinous cupula, referred to as a neuromast, is located between each pair of pores. Drag forces resulting from fluid motions induced inside the LLTC by pressure fluctuations in the external flow stimulate the neuromasts. This study, Part I of a two-part sequence, investigates the motion-sensing characteristics of the LLTC and how it may be used by fishes to detect wakes. To this end, an idealized geometrical/dynamical situation is examined that retains the essential problem physics. A two-level numerical model is developed that couples the vortical flow outside the LLTC to the flow stimulating the neuromasts within it. First, using a NavierStokes solver, we calculate the unsteady flow past an elongated rectangular prism and a fish downstream of it, with both objects moving at the same speed. By construction, the prism generates a clean, periodic vortex street in its wake. Then, also using the NavierStokes solver, the pressure field associated with this external flow is used to calculate the unsteady flow inside the LLTC of the fish, which creates the drag forces acting on the neuromast cupula. Although idealized, this externalinternal coupled flow model allows an investigation of the filtering properties and performance characteristics of the LLTC for a range of frequencies of biological interest. The results obtained here and in Part II show that the LLTC acts as a low-pass filter, preferentially damping high-frequency pressure gradient oscillations, and hence high-frequency accelerations, associated with the external flow. PMID:18926967

Barbier, Charlotte; Humphrey, Joseph A.C.

2008-01-01

73

Drag force acting on a neuromast in the fish lateral line trunk canal. I. Numerical modelling of external-internal flow coupling.  

PubMed

Fishes use a complex, multi-branched, mechanoreceptive organ called the lateral line to detect the motion of water in their immediate surroundings. This study is concerned with a subset of that organ referred to as the lateral line trunk canal (LLTC). The LLTC consists of a long tube no more than a few millimetres in diameter embedded immediately under the skin of the fish on each side of its body. In most fishes, pore-like openings are regularly distributed along the LLTC, and a minute sensor enveloped in a gelatinous cupula, referred to as a neuromast, is located between each pair of pores. Drag forces resulting from fluid motions induced inside the LLTC by pressure fluctuations in the external flow stimulate the neuromasts. This study, Part I of a two-part sequence, investigates the motion-sensing characteristics of the LLTC and how it may be used by fishes to detect wakes. To this end, an idealized geometrical/dynamical situation is examined that retains the essential problem physics. A two-level numerical model is developed that couples the vortical flow outside the LLTC to the flow stimulating the neuromasts within it. First, using a Navier-Stokes solver, we calculate the unsteady flow past an elongated rectangular prism and a fish downstream of it, with both objects moving at the same speed. By construction, the prism generates a clean, periodic vortex street in its wake. Then, also using the Navier-Stokes solver, the pressure field associated with this external flow is used to calculate the unsteady flow inside the LLTC of the fish, which creates the drag forces acting on the neuromast cupula. Although idealized, this external-internal coupled flow model allows an investigation of the filtering properties and performance characteristics of the LLTC for a range of frequencies of biological interest. The results obtained here and in Part II show that the LLTC acts as a low-pass filter, preferentially damping high-frequency pressure gradient oscillations, and hence high-frequency accelerations, associated with the external flow. PMID:18926967

Barbier, Charlotte; Humphrey, Joseph A C

2009-07-01

74

Review of current best practice and priorities for research in radiation oncology for elderly patients with cancer: the International Society of Geriatric Oncology (SIOG) task force.  

PubMed

Radiotherapy (RT) is a key component of the management of older cancer patients. Level I evidence in older patients is limited. The International Society of Geriatric Oncology (SIOG) established a task force to make recommendations for curative RT in older patients and to identify future research priorities. Evidence-based guidelines are provided for breast, lung, endometrial, prostate, rectal, pancreatic, oesophageal, head and neck, central nervous system malignancies and lymphomas. Patient selection should include comorbidity and geriatric evaluation. Advances in radiation planning and delivery improve target coverage, reduce toxicity and widen eligibility for treatment. Shorter courses of hypofractionated whole breast RT are safe and effective. Conformal RT and involved-field techniques without elective nodal irradiation have improved outcomes in non-small-cell lung cancer (NSCLC) without increasing toxicity. Where comorbidities preclude surgery, stereotactic body radiotherapy (SBRT) is an option for early-stage NSCLC and pancreatic cancer. Modern involved-field RT for lymphoma based on pre-treatment positron emission tomography data has reduced toxicity. Significant comorbidity is a relative contraindication to aggressive treatment in low-risk prostate cancer (PC). For intermediate-risk disease, 4-6 months of hormones are combined with external beam radiotherapy (EBRT). For high-risk PC, combined modality therapy (CMT) is advised. For high-intermediate risk, endometrial cancer vaginal brachytherapy is recommended. Short-course EBRT is an alternative to CMT in older patients with rectal cancer without significant comorbidities. Endorectal RT may be an option for early disease. For primary brain tumours, shorter courses of postoperative RT following maximal debulking provide equivalent survival to longer schedules. MGMT methylation status may help select older patients for temozolomide alone. Stereotactic RT provides an alternative to whole-brain RT in patients with limited brain metastases. Intensity-modulated radiation therapy provides an excellent technique to reduce dose to the carotids in head and neck cancer and improves locoregional control in oesophageal cancer. Best practice and research priorities are summarised. PMID:24625455

Kunkler, I H; Audisio, R; Belkacemi, Y; Betz, M; Gore, E; Hoffe, S; Kirova, Y; Koper, P; Lagrange, J-L; Markouizou, A; Pfeffer, R; Villa, S

2014-11-01

75

The molecular structure, conformation, potential to internal rotation and force field of 2,2,2-trifluoroacetamide as studied by gas electron diffraction and quantum chemical calculations  

NASA Astrophysics Data System (ADS)

2,2,2-Trifluoroacetamide (TFA) has been studied by electron diffraction (ED), ab initio Hartree-Fock (HF), density functional theory (DFT), and MP2 calculations. The calculations give one conformation with one of the C?F bonds anti to the C?O bond and a planar NH 2 group, except for MP2/6-311 + + G??, which predicts a slightly pyramidale NH 2 group. A molecular force field has been determined, and the fundamental frequencies have tentatively been assigned. The refined structural parameters were determined using constrained ED, i.e. ab initio results are included as constraints in the analysis. The structural parameters are: rg(N-H 4) = 1.040(4), rg(C?O) = 1.211(2), rg(C-N) = 1.362(4), rg = 1.562(1), rg(C-F 7) = 1.347(1), ? ?OCN = 126.5(2), ? ?CCN = 116.3(4), ? ?CCF 7 = 111.9(1), and ? ?CNH 4 = 118.5(11). Bond distances are in and bond angles in degrees. Uncertainties are one standard deviation from least squares refinement using a diagonal weight matrix and inclusion of the uncertainty in the electron wavelength. The structural parameters have been compared with related amides. The Fourier coefficients V3 and V6 in the potential to internal rotation of the CF 3 group, V(?) = 1/2?V 3?(1 - cos(3??)) + 1/2?V 6?(1 - cos(6??)) , are determined to be 2.7(4) and - 0.7(3) kJ/mol, respectively. The syn barrier is experimentally determined to be 2.6(4) kJ/mol, which is in good agreeent with theoretical calculations.

Gundersen, Snefrid; Samdal, Svein; Seip, Ragnhild; Shorokhov, Dmitry J.; Strand, Tor G.

1998-04-01

76

Forceful emplacement of the Eureka Valley-Joshua Flat-Beer Creek composite pluton into a structural basin in eastern California; internal structure and wall rock deformation  

NASA Astrophysics Data System (ADS)

Anisotropy of Magnetic Susceptibility parameters have been analyzed at 311 locations in the Eureka Valley-Joshua Flat-Beer Creek (EJB) pluton of eastern California. The large amount of data has allowed for the AMS parameters to be contoured using techniques that both reveal map-scale trends and emphasize small-scale differences. The contour maps suggest that magnetic susceptibility is dominantly controlled by composition of the magma but may also be affected by emplacement-related strain as the magma chamber inflated and forced the wall rocks outward. Pluton construction involved two major pulses of different composition magmas that were emplaced sequentially but with overlapping periods of crystallization. The magmas initially intruded as sill-like bodies into a structural basin. The magnetic foliation of the pluton cuts across internal magmatic contacts on the map scale and is parallel to local contacts between the pluton and surrounding metasedimentary wall rocks. The magnetic fabric is similar in orientation and symmetry to intense flattening strains recorded in the aureole rocks. The metasedimentary wall rocks have been shortened between 60 and 70% and this strain magnitude is approximately equal on the west, south, and east margins of the pluton. Strain in the wall rocks is dominantly flattening and concentrated into a narrow (1 km wide) inner aureole. Mapping of bedding/cleavage intersection lineations south of the pluton indicates that the magma made room for itself by translating the wall rocks outward and rotating the already inward dipping wall rocks of the structural basin to sub-vertical. Stretching of the inner aureole around an expanding magma chamber was responsible for the intense shortening. Limited data on the Marble Canyon pluton to the south of the EJB pluton indicates a very similar emplacement process.

Morgan, Sven; Law, Richard; de Saint Blanquat, Michel

2013-11-01

77

Force propagation and force generation in cells.  

PubMed

Determining how forces are produced by and propagated through the cytoskeleton (CSK) of the cell is of great interest as dynamic processes of the CSK are intimately correlated with many molecular signaling pathways. We are presenting a novel approach for integrating measurements on cell elasticity, transcellular force propagation, and cellular force generation to obtain a comprehensive description of dynamic and mechanical properties of the CSK under force loading. This approach uses a combination of scanning force microscopy (SFM) and Total Internal Reflection Fluorescence (TIRF) microscopy. We apply well-defined loading schemes onto the apical cell membrane of fibroblasts using the SFM and simultaneously use TIRF microscopy to image the topography of the basal cell membrane. The locally distinct changes of shape and depth of the cytoskeletal imprints onto the basal membrane are interpreted as results of force propagation through the cytoplasm. This observation provides evidence for the tensegrity model and demonstrates the usefulness of our approach that does not depend on potentially disturbing marker compounds. We confirm that the actin network greatly determines cell stiffness and represents the substrate that mediates force transduction through the cytoplasm of the cell. The latter is an essential feature of tensegrity. Most importantly, our new finding that, both intact actin and microtubule networks are required for enabling the cell to produce work, can only be understood within the framework of the tensegrity model. We also provide, for the first time, a direct measurement of the cell's mechanical power output under compression at two femtowatts. PMID:20607861

Jonas, Oliver; Duschl, Claus

2010-09-01

78

Air Force seal activities  

Microsoft Academic Search

Seal technology development is an important part of the Air Force's participation in the Integrated High Performance Turbine Engine Technology (IHPTET) initiative, the joint DOD, NASA, ARPA, and industry endeavor to double turbine engine capabilities by the turn of the century. Significant performance and efficiency improvements can be obtained through reducing internal flow system leakage, but seal environment requirements continue

Ellen R. Mayhew

1994-01-01

79

Labor Force  

ERIC Educational Resources Information Center

The labor force is the number of people ages 16 or older who are either working or looking for work. It does not include active-duty military personnel or the institutionalized population, such as prison inmates. Determining the size of the labor force is a way of determining how big the economy can get. The size of the labor force depends on two

Occupational Outlook Quarterly, 2012

2012-01-01

80

Forced and Internal Twentieth-Century SST Trends in the North Atlantic* MINGFANG TING, YOCHANAN KUSHNIR, RICHARD SEAGER, AND CUIHUA LI  

E-print Network

since then. This natural variation, referred to previously as the Atlantic Multidecadal Oscillation (AMO to detect and attribute long-term (multidecadal) twentieth-century North Atlantic (NA) SST changes multidecadal ``oscillation'' that is outside of the range of the model-simulated, forced com- ponent and most

81

Earth Force  

NSDL National Science Digital Library

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

82

Air Force Seal Programs  

NASA Technical Reports Server (NTRS)

Seal technology development is an important part of the Air Force's participation in the Integrated High Performance Turbine Engine Technology (IHPTET) initiative, the joint DOD, NASA, ARPA, and industry endeavor to double turbine engine capabilities by the turn of the century. Significant performance and efficiency improvements can be obtained through reducing internal flow system leakage, but seal environment requirements continue to become more extreme as the engine thermodynamic cycles advance towards these IHPTET goals. Seal technology continues to be pursued by the Air Force to control leakage at the required conditions. This presentation briefly describes current seal research and development programs and gives a summary of seal applications in demonstrator and developmental engines.

Mayhew, Ellen R.

1996-01-01

83

Buoyant Force  

NSDL National Science Digital Library

This activity is a lab where students gather data on buoyant force and height of and object being submerged in two different types of fluids. The slope of the buoyant force and height is proportional to the density of the fluid. Students compare the densities of the fluids calculated with the actual densities.

Renae Garski, Bigfork High School, Bigfork, MN, based on an original activity from Science Workshop, p. 115

84

One Force  

NASA Astrophysics Data System (ADS)

There is only one entity that can extend force and couple through space; and it should be apparent that Electromagnetism is that entity. In the cases of the nuclear strong force and the nuclear weak force, this is the same fundamental Electromagnetism manifesting itself in two different ways in the nucleus. It remains the same basic Electromagnetism. On the other hand, General Relativity fails to produce force at a distance, fails the Cavendish experiment, and does not allow an apple to fall to the ground. The result shows there is only Electromagnetism that functions through physical nature providing gravity, actions in the nucleus, as well as all other physical actions universally, including Gravity and Gravitation. There are many direct proofs of this, the same proofs as in NUCLEAR QUANTUM GRAVITATION. In contrast, General Relativity plainly relies on fallacy abstract and incoherent proofs; proofs which have now been mostly disproved. In the past it was deemed necessary by some to have an "ether" to propagate Electromagnetic waves. The fallacy concept of time space needs "space distortions" in order to cause gravity. However, Electromagnetic gravity does not have this problem. Clearly there is only ONE FORCE that causes Gravity, Electromagnetism, the Nuclear Strong Force, and the Nuclear Weak Force, and that ONE FORCE is Electromagnetism.

Kotas, Ronald R.

2002-04-01

85

Labor Force  

ERIC Educational Resources Information Center

The labor force is the number of people aged 16 or older who are either working or looking for work. It does not include active-duty military personnel or institutionalized people, such as prison inmates. Quantifying this total supply of labor is a way of determining how big the economy can get. Labor force participation rates vary significantly

Occupational Outlook Quarterly, 2010

2010-01-01

86

Dam Forces  

NSDL National Science Digital Library

Students learn how the force of water helps determine the size and shape of dams. They use clay to build models of four types of dams, and observe the force of the water against each type. They conclude by deciding which type of dam they, as Splash Engineering engineers, will design for Thirsty County.

2014-09-18

87

Force sensor  

DOEpatents

A force sensor and related method for determining force components is described. The force sensor includes a deformable medium having a contact surface against which a force can be applied, a signal generator for generating signals that travel through the deformable medium to the contact surface, a signal receptor for receiving the signal reflected from the contact surface, a generation controller, a reception controller, and a force determination apparatus. The signal generator has one or more signal generation regions for generating the signals. The generation controller selects and activates the signal generation regions. The signal receptor has one or more signal reception regions for receiving signals and for generating detections signals in response thereto. The reception controller selects signal reception regions and detects the detection signals. The force determination apparatus measures signal transit time by timing activation and detection and, optionally, determines force components for selected cross-field intersections. The timer which times by activation and detection can be any means for measuring signal transit time. A cross-field intersection is defined by the overlap of a signal generation region and a signal reception region.

Grahn, A.R.

1993-05-11

88

Force sensor  

DOEpatents

A force sensor and related method for determining force components. The force sensor includes a deformable medium having a contact surface against which a force can be applied, a signal generator for generating signals that travel through the deformable medium to the contact surface, a signal receptor for receiving the signal reflected from the contact surface, a generation controller, a reception controller, and a force determination apparatus. The signal generator has one or more signal generation regions for generating the signals. The generation controller selects and activates the signal generation regions. The signal receptor has one or more signal reception regions for receiving signals and for generating detections signals in response thereto. The reception controller selects signal reception regions and detects the detection signals. The force determination apparatus measures signal transit time by timing activation and detection and, optionally, determines force components for selected cross-field intersections. The timer which times by activation and detection can be any means for measuring signal transit time. A cross-field intersection is defined by the overlap of a signal generation region and a signal reception region.

Grahn, Allen R. (Salt Lake City, UT)

1993-01-01

89

International Studies Degree  

E-print Network

BGSU® n n n What I did with my International Studies Degree Bowing Green State University 103 Corporation Self-employed/Business Owner Indy Associates, Original Impulse Senior Associate International Force Research Laboratory Director, International Trade Office State of Colorado ­ Office of Economic

Moore, Paul A.

90

From local force-flux relationships to internal dissipations and their impact on heat engine performance: the illustrative case of a thermoelectric generator.  

PubMed

We present an in-depth analysis of the sometimes understated role of the principle of energy conservation in linear irreversible thermodynamics. Our case study is that of a thermoelectric generator (TEG), which is a heat engine of choice in irreversible thermodynamics, owing to the coupling between the electrical and heat fluxes. We show why Onsager's reciprocal relations must be considered locally and how internal dissipative processes emerge from the extension of these relations to a global scale: The linear behavior of a heat engine at the local scale is associated with a dissipation process that must partake in the global energy balance. We discuss the consequences of internal dissipations on the so-called efficiency at maximum power, in the light of our comparative analyses of exoreversibility and endoreversibility on the one hand and of two classes of heat engines, autonomous and periodically driven, on the other hand. Finally, basing our analysis on energy conservation, we also discuss recent works which claim the possibility to overcome the traditional boundaries on efficiency imposed by finite-time thermodynamics in thermoelectric systems with broken time-reversal symmetry; this we do by introducing a "thermal" thermopower and an "electrical" thermopower which permits an analysis of the thermoelectric response of the TEG considering a possible dissymmetry between the electrical/thermal and the thermal/electrical couplings. PMID:24032805

Apertet, Y; Ouerdane, H; Goupil, C; Lecoeur, Ph

2013-08-01

91

Management of elderly patients with NSCLC; updated expert's opinion paper: EORTC Elderly Task Force, Lung Cancer Group and International Society for Geriatric Oncology.  

PubMed

Non-small-cell lung cancer (NSCLC) is a very common disease in the elderly population and its incidence in this particular population is expected to increase further, because of the ageing of the Western population. Despite this, limited data are available for the treatment of these patients and, therefore, the development of evidence-based treatment recommendations is challenging. In 2010, European Organization for Research and Treatment of Cancer (EORTC) took an initiative in collaboration with International Society of Geriatric Oncology (SIOG) and created an experts panel that provided an experts' opinion consensus paper for the management of elderly NSCLC patients. Since this publication, important new data are available and EORTC and SIOG recommended to update the 2010 recommendations. Besides recommendations for surgery, adjuvant chemotherapy and radiotherapy, treatment of locally advanced and metastatic disease, recommendations were expanded, to include data on patient preferences and geriatric assessment. PMID:24638905

Pallis, A G; Gridelli, C; Wedding, U; Faivre-Finn, C; Veronesi, G; Jaklitsch, M; Luciani, A; O'Brien, M

2014-07-01

92

Charge ordering, internal structural parameters, and magnetic susceptibility of Nd2/3Ca1/3MnO3: driving forces of a phase transition  

NASA Astrophysics Data System (ADS)

The temperature dependences of the long diagonals dMn -O of the MnO6 octahedron and the magnetic susceptibility ? of Nd2/3Ca1/3MnO3 in the temperature interval 100-290K are investigated. The functions dMn -O(T) and ?(T ) are found to have anomalies in the charge-ordering range (Tco?212K). The sharp decrease of the diagonal dMn -O2s agrees with phase-transition notions, according to which the spatial modulation of the charge density is due to the modulation of the Mn-Mn bond lengths. The most likely driving forces of the transition are the Peierls lattice instability and Jahn-Teller stability of the MnO6 octahedron at the Mn3+ ions. The hysteresis of the temperature dependence ?(T ) in the paramagnetic region shows indirectly that structural phase separation occurs together with the transition. The parameters of the function ?(T ) indicate that ferromagnetic clusters consisting of one, two, or three ion pairs Mn3+-Mn4+ form in the system in the temperature intervals 274K?T?290K, 224K?T?252K, and 130K?T?198K, respectively.

Beznosov, A. B.; Fertman, E. L.; Desnenko, V. A.

2008-08-01

93

Forces Lab  

NSDL National Science Digital Library

This set of online simulations shows the forces that may be at work on geologic structures or on man-made structures during an earthquake. Users can see examples of compression, tension, bending, and torsion. Each simulation also features a link to a photo of a real-life example.

94

Disturbance Observer Based Force Control of Robot Manipulator without Force Sensor  

Microsoft Academic Search

In this paper, a force estimation method is proposed for force control without force sensor. A disturbance observer is applied to each joint of an n degrees of freedom manipulator to obtain a simple equivalent robot dynamics being represented as an n independent double integrator system. To estimate the output of disturbance observer due to internal torque, the disturbance observer

Kwang Sik Eom; Il Hong Suh; Wan Kyun Chung; Oh Sang-rok

1998-01-01

95

Forced Migration Review  

NSDL National Science Digital Library

Published tri-annually since January 1998, the Forced Migration Review (FMR) is the in-house journal of the Refugee Studies Centre at the University of Oxford. The journal (and its online edition made available on this site) is published in English, Arabic, and Spanish, and "provides the humanitarian community with a practice-oriented forum for debate on issues facing refugees and internally displaced people in order to improve policy and practice." From the site, visitors can browse through single articles or complete issues of the journal all the way back to 1998. Many of the issues are dedicated to a single theme, including recent issues which have been titled When does internal displacement end? and Reproductive health for displaced people: Investing in the future. The site also provides ample information on submitting articles to the journal, material on the current editorial board, and the themes for upcoming issues. Rounding out the site is a collection of related links for consideration, organized into topics such as international law, reproductive health and forced migration research institutes and centers.

96

Differential force balances during levitation  

NASA Astrophysics Data System (ADS)

The simplest arithmetic of inertial, buoyant, magnetic and electrokinetic levitation is explored in the context of a model living system with acceleration-sensitive structures in which motion, if allowed, produces a biological effect. The simple model is a finite-sized object enclosed within another finite-sized object suspended in an outer fluid (liquid or vapor) medium. The inner object has density and electrical and magnetic properties quantitatively different from those of the outer object and the medium. In inertial levitation (weightlessness) inertial accelerations are balanced, and the forces due to them are canceled in accordance with Newtons third law. In the presence of inertial acceleration (gravity, centrifugal) motionlessness depends on a balance between the levitating force and the inertial force. If the inner and outer objects differ in density one or the other will be subjected to an unbalanced force when one object is levitated by any other force (buoyant, magnetic, electrokinetic). The requirements for motionlessness of the internal object in the presence of a levitating force are equality of density in the case of buoyant levitation, equality of magnetic susceptibility in the case of magnetic levitation, and equality of zeta potential and dielectric constant in the case of electrokinetic levitation. Examples of internal acceleration-sensitive structures are cellular organelles and the organs of advanced plants and animals. For these structures fundamental physical data are important in the interpretation of the effects of forces used for levitation.

Todd, Paul

97

Air Force seal activities  

NASA Technical Reports Server (NTRS)

Seal technology development is an important part of the Air Force's participation in the Integrated High Performance Turbine Engine Technology (IHPTET) initiative, the joint DOD, NASA, ARPA, and industry endeavor to double turbine engine capabilities by the turn of the century. Significant performance and efficiency improvements can be obtained through reducing internal flow system leakage, but seal environment requirements continue to become more extreme as the engine thermodynamic cycles advance towards these IHPTET goals. Brush seal technology continues to be pursued by the Air Force to reduce leakage at the required conditions. Likewise, challenges in engine mainshaft air/oil seals are also being addressed. Counter-rotating intershaft applications within the IHPTET initiative involve very high rubbing velocities. This viewgraph presentation briefly describes past and current seal research and development programs and gives a summary of seal applications in demonstrator and developmental engine testing.

Mayhew, Ellen R.

1994-01-01

98

Air Force seal activities  

NASA Astrophysics Data System (ADS)

Seal technology development is an important part of the Air Force's participation in the Integrated High Performance Turbine Engine Technology (IHPTET) initiative, the joint DOD, NASA, ARPA, and industry endeavor to double turbine engine capabilities by the turn of the century. Significant performance and efficiency improvements can be obtained through reducing internal flow system leakage, but seal environment requirements continue to become more extreme as the engine thermodynamic cycles advance towards these IHPTET goals. Brush seal technology continues to be pursued by the Air Force to reduce leakage at the required conditions. Likewise, challenges in engine mainshaft air/oil seals are also being addressed. Counter-rotating intershaft applications within the IHPTET initiative involve very high rubbing velocities. This viewgraph presentation briefly describes past and current seal research and development programs and gives a summary of seal applications in demonstrator and developmental engine testing.

Mayhew, Ellen R.

1994-07-01

99

Friction Force  

NSDL National Science Digital Library

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

2014-09-18

100

A Forcing Axiom and Chang's Conjecture, Part II Tadatoshi MIYAMOTO  

E-print Network

A Forcing Axiom and Chang's Conjecture, Part II Tadatoshi MIYAMOTO January, 30th, 2012 Abstract We consider a form of forcing axiom which has a sort of combined strength of Chang's Conjecture and internal genericity. We study the effects of this forcing axiom with the Cohen forcing in this talk. We observe

Kikuchi, Makoto

101

INTERNATIONAL International Internship for  

E-print Network

OFFICE OF INTERNATIONAL AFFAIRS International Internship for Global Leadership Program Student Portugal ­ Laura Sieger Ukraine ­ Mary Brune 2012 Internship Locations #12;Dear Friends and Colleagues of Lehigh University: The International Internship for Global Leadership Program provides Lehigh students

Napier, Terrence

102

Knee joint forces: prediction, measurement, and significance  

PubMed Central

Knee forces are highly significant in osteoarthritis and in the survival and function of knee arthroplasty. A large number of studies have attempted to estimate forces around the knee during various activities. Several approaches have been used to relate knee kinematics and external forces to internal joint contact forces, the most popular being inverse dynamics, forward dynamics, and static body analyses. Knee forces have also been measured in vivo after knee arthroplasty, which serves as valuable validation of computational predictions. This review summarizes the results of published studies that measured knee forces for various activities. The efficacy of various methods to alter knee force distribution, such as gait modification, orthotics, walking aids, and custom treadmills are analyzed. Current gaps in our knowledge are identified and directions for future research in this area are outlined. PMID:22468461

DLima, Darryl D.; Fregly, Benjamin J.; Patil, Shantanu; Steklov, Nikolai; Colwell, Clifford W.

2011-01-01

103

Financial Action Task Force  

NSDL National Science Digital Library

Created in 1989, the Financial Action Task Force (FATF) is an inter-governmental body whose purpose is "the development and promotion of national and international policies to combat money laundering and terrorist financing." Users who are new to the site can get started quickly by looking over the "Quick Links" section on the right-hand side of the homepage. Here they will find a handbook that details how the FATF creates its profiles, information on the methodology, and primary recommendations for creating a coherent set of counter-measures against money laundering. Also, the site includes a "Publications" area, which contains short summaries of reports, along with annual reports dating from 1990 and newsletters from 2007. Finally, the site also contains a listing of recent news items and upcoming events and conferences sponsored by the FATF.

104

Attentional Focusing Instructions and Force Production  

PubMed Central

Research progress assessing the role of attentional focusing instructions on skill acquisition and performance has lead researchers to apply this approach to force production tasks. Initial converging evidence indicates that force production tasks are sensitive to verbal instruction; externally focused instructions (onto movement outcomes, or onto the object force is being exerted against) are shown to be more beneficial than internally focused instructions (focusing attention onto the movements being executed). These benefits are observed for maximal and accurate force production, as well as the maintenance of force production in prolonged tasks. A range of mechanisms are identified supporting the proposal that an external focus promotes movement efficiency in line with energy and effort conservation. Future research is required to assess how this developing body of work interacts with the broader understanding of psychological and physiological factors implicated in the effective production, maintenance, and limitation of maximal or sub-maximal forces. PMID:21833266

Marchant, David C.

2010-01-01

105

75 FR 43944 - Defense Science Board; Task Force on Trends and Implications of Climate Change for National and...  

Federal Register 2010, 2011, 2012, 2013

...Science Board; Task Force on Trends and Implications of Climate Change for National and International Security AGENCY: Department...Science Board Task Force on Trends and Implications of Climate Change for National and International Security will meet...

2010-07-27

106

75 FR 34438 - Defense Science Board Task Force on Trends and Implications of Climate Change for National and...  

Federal Register 2010, 2011, 2012, 2013

...Science Board Task Force on Trends and Implications of Climate Change for National and International Security AGENCY: Department...Science Board Task Force on Trends and Implications of Climate Change for National and International Security will meet...

2010-06-17

107

Air Force brush seal programs  

NASA Astrophysics Data System (ADS)

Aggressive pursuit of increased performance in gas turbine engines is driving the thermodynamic cycle to higher pressure ratios, bypass ratios, and turbine inlet temperatures. As these parameters increase, internal air system and resultant thermodynamic cycle losses increase. This conflict of reducing internal airflows while increasing thermodynamic efficiency and performance is putting more emphasis on improvements to the internal flow system. One improvement that has been and continues to be pursued by the Air Force for both man-rated and expendable turbine engine applications is the brush seal. This presentation briefly describes both past and current brush seal research and development programs and gives a summary of demonstrator and developmental engine testing of brush seals.

Dowler, Connie

1993-10-01

108

Air Force brush seal programs  

NASA Technical Reports Server (NTRS)

Aggressive pursuit of increased performance in gas turbine engines is driving the thermodynamic cycle to higher pressure ratios, bypass ratios, and turbine inlet temperatures. As these parameters increase, internal air system and resultant thermodynamic cycle losses increase. This conflict of reducing internal airflows while increasing thermodynamic efficiency and performance is putting more emphasis on improvements to the internal flow system. One improvement that has been and continues to be pursued by the Air Force for both man-rated and expendable turbine engine applications is the brush seal. This presentation briefly describes both past and current brush seal research and development programs and gives a summary of demonstrator and developmental engine testing of brush seals.

Dowler, Connie

1993-01-01

109

Force regulation in multiple-manipulator systems  

NASA Technical Reports Server (NTRS)

A new intuitively appealing interpretation of the internal force in a multiple-arm system is presented. The static gravity-free case is considered where internal force has a well-founded physical meaning. The case is extended to the general dynamic case by removing the inertial force through balancing it with the minimum amount of contact force. The remaining component in the contact force is considered to be the sole contributor to the inertial force. Existing techniques for force control can be used to obtain various stabilizing force set point control laws. Particular attention is given to the motion control strategy for multiple arm systems. Three types of control laws, feedback linearization, arms-as-actuators, and passive control, are addressed. The first two techniques provide simplified control tuning but require much model information. The latter approach is considered to be very robust with respect to the model, but good transient performance is more challenging to obtain. It is suggested to combine one of the model-based approaches with the passive control approach.

Wen, John T.; Murphy, Steve H.

1992-01-01

110

Common Force Field Thermodynamics of Cholesterol  

PubMed Central

Four different force fields are examined for dynamic characteristics using cholesterol as a case study. The extent to which various types of internal degrees of freedom become thermodynamically relevant is evaluated by means of principal component analysis. More complex degrees of freedom (angle bending, dihedral rotations) show a trend towards force field independence. Moreover, charge assignments for membrane-embedded compounds are revealed to be critical with significant impact on biological reasoning. PMID:24302856

Giangreco, Francesco; Yamamoto, Eiji; Hirano, Yoshinori; di Giosia, Matteo; Zerbetto, Francesco; Yasuoka, Kenji; Narumi, Tetsu; Yasui, Masato; Hfinger, Siegfried

2013-01-01

111

THE QUANTIZED INERTIAL FORCE  

Microsoft Academic Search

Einstein, in his general relativity theory, defined the inertial force equivalent to the gravitational force, that is in his (equivalence principle). In this work we reach to the quantized inertial force, where we describe the inertial force as a function of the frequency.

Azzam K. AlMosallami

112

Knudsen forces on microcantilevers  

NASA Astrophysics Data System (ADS)

When two surfaces at two different temperatures are separated by a distance comparable to a mean-free path of the molecules of the ambient medium, the surfaces experience Knudsen force. This mechanical force can be important in microelectromechanical systems and in atomic force microscopy. A theoretical discussion of the magnitude of the forces and the conditions where they can be encountered is discussed. A potential application of the Knudsen force in designing a cantilever-based vacuum gauge is discussed.

Passian, A.; Wig, A.; Meriaudeau, F.; Ferrell, T. L.; Thundat, T.

2002-11-01

113

Intermolecular Forces (Netorials)  

NSDL National Science Digital Library

Intermolecular Forces: this is a resource in the collection "Netorials". In this resource there is a review of Lewis structures, molecular geometry, electronegativity, or molecular polarity. After that, you can learn about the forces of attraction that exist between molecules. This module explores London forces and dipole-dipole forces (including hydrogen bonds). The Netorials cover selected topics in first-year chemistry including: Chemical Reactions, Stoichiometry, Thermodynamics, Intermolecular Forces, Acids & Bases, Biomolecules, and Electrochemistry.

114

Discrete element simulations of bed force anomalies due to force chains in dense granular flows  

NASA Astrophysics Data System (ADS)

Surficial flows on volcanic edifices are often comprised of high concentrations of granular materials either derived from juvenile eruptive material or material sourced from an unstable edifice. Although much attention has been given to granular flow mobility, the physics that govern flow internal behavior and substrate interaction are still poorly understood. Recent laboratory experiments have shown that force chains transmit extreme localized forces to the substrates of free surface granular flows. In this work we combine computational and experimental approaches to investigate the forces at the bed of a simplified granular flow. A photoelastic experimental approach is used to resolve discrete forces in the granular flows. We also conduct discrete element model (DEM) simulations, using input parameters derived from measureable physical material properties of experimental and natural materials, that successfully reproduce the experimental bed forces generated by filamentary force chain structures observed in free surface granular flows. The DEM results show particular sensitivity to values prescribed for contact stiffness, which is in contrast with previous reports indicating that stiffness values have insignificant influence on flow behavior. The transient forces at the bed generated by force chain structures can greatly exceed (by several 100%) the bed forces predicted from continuum approaches, and our simulation results imply that natural materials are more prone to excessive bed forces than photoelastic materials due to their larger contact stiffnesses. This work suggests that force chain activity may play an important role in the bed physics of dense volcanic flows by influencing substrate entrainment.

Estep, Joe; Dufek, Josef

2013-03-01

115

Forced oscillations of pendant drops  

SciTech Connect

The efficiency of droplet/bubble breakup in multiphase contactors can be increased by applying external fields at resonance frequencies of the drops/bubbles. Experimental and theoretical techniques, developed for the study of forced oscillation of pendant drops on nozzles, are used to gain a fundamental understanding of drop response as a function of forcing frequency. Preliminary results of drop oscillations caused by electrical and flow perturbation techniques indicate that the relationship of resonance frequency to drop size for a given fluid system is not affected by the means of excitation. Computational techniques may be used to gain insight into phenomena which are difficult to probe by experiment, such as internal flow fields. The understanding gained by use of these techniques will be indispensable in design and operation of future multiphase contacting devices.

DePaoli, D.W.; Basaran, O.A.; Scott, T.C. [Oak Ridge National Laboratory, TN (United States)] [and others

1995-04-01

116

HOW TO DESIGN NUTRITIONAL INTERVENTION TRIALS TO SLOW COGNITIVE DECLINE IN APPARENTLY HEALTHY POPULATIONS AND APPLY FOR EFFICACY CLAIMS: A STATEMENT FROM THE INTERNATIONAL ACADEMY ON NUTRITION AND AGING TASK FORCE  

PubMed Central

Interventions are crucial as they offer simple and inexpensive public health solutions that will be useful over the long term use. A Task Force on designing trials of nutritional interventions to slow cognitive decline in older adults was held in Toulouse in September 2012. The aim of the Task Force was to bring together leading experts from academia, the food industry and regulatory agencies to determine the best trial designs that would enable us to reach our goal of maintaining or improving cognitive function in apparently healthy aging people. An associated challenge for this Task Force was to determine the type of trials required by the Public Food Agencies for assessing the impact of nutritional compounds in comparison to well established requirements for drug trials. Although the required quality of the study design, rationale and statistical analysis remains the same, the studies designed to show reduction of cognitive decline require a long duration and the objectives of this task force was to determine best design for these trials. Two specific needs were identified to support trials of nutritional interventions: 1- Risk- reduction strategies are needed to tackle the growing burden of cognitive decline that may lead to dementia, 2- Innovative study designs are needed to improve the quality of these studies. PMID:23933873

Ferry, M.; Coley, N.; Andrieu, S.; Bonhomme, C.; Caubere, J.P.; Cesari, M.; Gautry, J.; Garcia Sanchez, I.; Hugonot, L.; Mansuy, L.; Pahor, M.; Pariente, J.; Ritz, P.; Salva, A.; Sijben, J.; Wieggers, R.; Ythier-Moury, P.; Zaim, M.; Zetlaoui, J.; Vellas, B.

2015-01-01

117

Forces in the Atmosphere  

NSDL National Science Digital Library

This undergraduate meteorology tutorial is about understanding the forces that cause the motion of air, producing winds and changes of weather. It discusses how these forces tend to balance each other, and how they produce the wind.

Nielsen-Gammon, John

1996-01-01

118

Three-Nucleon Forces  

E-print Network

The role of three-nucleon forces in ab initio calculations of nuclear systems is investigated. The difference between genuine and induced many-nucleon forces is emphasized. Induced forces arise in the process of solving the nuclear many-body problem as technical intermediaries towards calculationally converged results. Genuine forces make up the Hamiltonian; they represent the chosen underlying dynamics. The hierarchy of contributions arising from two-, three- and many-nucleon forces is discussed. Signals for the need of the inclusion of genuine three-nucleon forces are studied in nuclear systems, technically best under control, especially in three-nucleon and four-nucleon systems. Genuine three-nucleon forces are important for details in the decription of some observables. Their contributions to observables are small on the scale set by two-nucleon forces.

Peter U. Sauer

2014-07-25

119

Forces in One Dimension  

NSDL National Science Digital Library

The representation depicts the relationship between frictional and applied forces for a variety of objects in an interactive simulation. As the user manipulates objects, charts show the resulting forces and depict position, velocity, and acceleration vs. time.

120

U.S. Transport Task Force 2010  

SciTech Connect

The Transport Task Force (TTF) Meeting is a venue for vigorous scientific discourse and discussion on topics in transport and turbulence in fusion plasmas. Its participation is international. The 2010 meeting was highly effective, with 139 registered participants and 131 presentations. This is remarkable for an even year (IAEA year) meeting. The meeting clearly fostered progress in understanding and control of turbulent transport.

Diamond, P.H.

2011-09-21

121

Force and Motion  

NSDL National Science Digital Library

Explore interactive sites and sites with information about putting objects into motion with different forces. 1. Read the top two sections about Motion and Force and then answer questions #1 and #2 on your worksheet. Force and Motion Information 2. Scroll down and read the section about inertia. Force and Motion Information Then click the box that says "law of inertia" and learn more about inertia on this page. Newton s Laws Now answer #3 ...

Carrie Benson

2013-01-31

122

Microprocessor controlled force actuator  

NASA Technical Reports Server (NTRS)

The mechanical and electrical design of a prototype force actuator for vibration control of large space structures (LSS) is described. The force actuator is an electromagnetic system that produces a force by reacting against a proof-mass. The actuator has two colocated sensors, a digital microcontroller, and a power amplifier. The total weight of actuator is .998 kg. The actuator has a steady state force output of approximately 2.75 N from approximately 2 Hz to well beyond 1000 Hz.

Zimmerman, D. C.; Inman, D. J.; Horner, G. C.

1986-01-01

123

Crossflow force transducer. [LMFBR  

SciTech Connect

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

Mulcahy, T.M.

1982-05-01

124

Forces: Pushing and Pulling  

NSDL National Science Digital Library

This lesson demonstrates how students can use cause and effect to describe how objects move using a push or pull (forces). The students will understand that forces put objects in motion and that a strong force could change the direction and speed of an object.

2012-10-12

125

Forces in General Relativity  

ERIC Educational Resources Information Center

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

Ridgely, Charles T.

2010-01-01

126

Concepts of Force  

NSDL National Science Digital Library

This book guides you through the history of the concept of force. Beginning in Acient Greece, Jammer analyzes their ideas about force and how it evolved through the centuries, leading in to the research of Newton, Liebniz, and Kepler, and showing how force applies in modern day physics.

Jammer, Max

2006-07-22

127

Digital Library Task Force  

Microsoft Academic Search

In 1995, the IEEE Computer Society established the Task Force on Digital Libraries as a first step leading to a full-fledged Technical Committee. The task force is to promote research in the theory and practice of all aspects of digital libraries. The task force sponsors activities that benefit its members and profession. Such activities include sponsoring and co-sponsoring symposia, sessions

N. R. Adam; R. Holowczak; M. Halem; N. Lal; Y. Yesha

1996-01-01

128

Solvation force simulations in atomic force microscopy  

NASA Astrophysics Data System (ADS)

Solvation force oscillation in octamethylcyclotetrasiloxane (OMCTS) versus the distance between an atomic force microscope (AFM) tip and mica substrate has been studied through molecular dynamics simulations. A driving spring model in a liquid-vapor molecular ensemble is used to explore the force oscillation mechanism. It has been found that OMCTS fluid in tip-substrate contact has a strong tendency to form a layered structure, starting from n = 8 layers. The force profile obtained from simulation is qualitatively similar to those in contact mode AFM experiments. However, the bulk-like diffusion and rotation of OMCTS molecules underneath the AFM tip suggest that, under the tip-substrate confinement geometry, the layered OMCTS film cannot form a solidified structure except under n = 2 extreme contact-layer confinement.

Xu, Rong-Guang; Leng, Yongsheng

2014-06-01

129

HRP ForceShoe Evaluation - Duration: 1:37.  

NASA Video Gallery

Maintaining astronaut bone and muscle health in microgravity is an ongoing concern for NASA. In May of 2014, NASA delivered the ForceShoe, designed by XSENS, to the International Space Station (ISS...

130

Mechanical forces of fission yeast growth.  

PubMed

Mechanical properties contribute to the control of cell size, morphogenesis, development, and lifestyle of fungal cells. Tip growth can be understood by a viscoplastic model, in which growth is derived by high internal turgor pressure and cell-wall elasticity. To understand how these properties regulate growth in the rod-shaped fission yeast Schizosaccaromyces pombe, we devised femtoliter cylindrical polydimethylsiloxane (PDMS) microchambers with varying elasticity as force sensors for single cells. By buckling cells in these chambers, we determine the elastic surface modulus of the cell wall to be 20.2 +/- 6.1 N.m(-1). By analyzing the growth of the cells as they push against the walls of the chamber, we derive force-velocity relationships and values for internal effective turgor pressure of 0.85 +/- 0.15 MPa and a growth-stalling force of 11 +/- 3 muN. The behavior of cells buckling under the force of their own growth provides an independent test of this model and parameters. Force generation is dependent on turgor pressure and a glycerol synthesis gene, gpd1(+) (glycerol-3-phosphate dehydrogenase), and is independent of actin cables. This study develops a quantitative framework for tip cell growth and characterizes mechanisms of force generation that contribute to fungal invasion into host tissues. PMID:19500986

Minc, Nicolas; Boudaoud, Arezki; Chang, Fred

2009-07-14

131

Force Concept Inventory: Forces and Speed  

NSDL National Science Digital Library

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

Wolfgang Christian

132

Force Concept Inventory: Forces and Speed  

NSDL National Science Digital Library

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

Wolfgang Christian

133

System of wood combustion employing forced draft  

SciTech Connect

A system of wood combustion employing forced draft is disclosed and comprises a forced draft air and flue arrangement which is utilized with a typical wood heater or wood stove. The forced air and flue arrangement includes a blower, a plenum on which the blower is attached, a panel to which the plenum is attached having air inlets formed therethrough, the air inlets being internal to the plenum, and a flue arrangement attached to the other side of the panel. The flue arrangement includes ducts leading from the air inlets, the ducts having air nozzle slits formed on the other end thereof which are communicable with the internal portions of the wood heater or wood stove. Forced air from the blower enters the combustion chamber through the air nozzle slits. Immediately adjacent to the air nozzle slits and formed as a portion of the flue arrangement is an internal flue outlet for providing an exhaust exit for combustion gases, the flue outlet being communicable with an exhaust pipe. This forced draft air and flue arrangement provides for more complete combustion by combining secondary combustion of the excess air and unburned combustibles released during a previous primary combustion with the current primary combustion of the wood fuel thereby minimizing the amount of excess air and unburned combustibles and thereby improving the combustion efficiency of the wood stove. This is accomplished by forcing the combustion exhaust gases which are attempting to exit through the flue outlet to recirculate back into the combustion chamber. Directly adjacent locations of the air nozzle slits with the flue outlet causes this forced recirculation of the excess air and unburned combustibles generated during the primary combustion of the wood fuel.

Stark, I.

1981-12-08

134

In-plane video force microscopy of morphogenesis in epithelia  

NASA Astrophysics Data System (ADS)

Video force microscopy (VFM) is a technique that takes segmented time-lapse images as input and makes least-squares estimates for the cell-edge tensions and cell-internal pressures needed to drive observed changes in cell shape. VFM has previously been used to estimate the cell-level forces that drive invagination during Drosophila gastrulation. Doing so required time-lapse images containing entire cross-sections of the embryo. Here, we extend video force microscopy to in-plane images of epithelia -- including examples in which the images cover only a small region of a larger epithelium. This extension requires imposition of constraints on the average cell-internal pressure and the average stress external to the observed patch. We will demonstrate successful estimation of forces in exact models, as well as anomalous cases that prevent successful force estimation. We will then show applications of this technique for inferring the forces driving Drosophila germband retraction and wound healing.

Hutson, M. Shane; Mashburn, David; Copenhaver, Eric; McCleery, W. Tyler; Veldhuis, Jim; Kim, Steven; Brodland, G. Wayne

2013-03-01

135

Three-nucleon forces and the trinucleon bound states  

SciTech Connect

A summary of the bound-state working group session of the ''International Symposium on the Three-Body Force in the Three-Nucleon System'' is presented. The paper includes a discussion of presently used calculational techniques, experimental evidence for three-nucleon forces in trinucleon ground states, future directions in theoretical research and future experimental research. (DWL)

Friar, J.L.; Frois, B.

1986-01-01

136

Position And Force Control For Multiple-Arm Robots  

NASA Technical Reports Server (NTRS)

Number of arms increased without introducing undue complexity. Strategy and computer architecture developed for simultaneous control of positions of number of robot arms manipulating same object and of forces and torques that arms exert on object. Scheme enables coordinated manipulation of object, causing it to move along assigned trajectory and be subjected to assigned internal forces and torques.

Hayati, Samad A.

1988-01-01

137

Driving Forces of Third Party Logistics Innovation in China  

Microsoft Academic Search

Logistics industry has been set up as a strategic industry in China. With the structural changing of traditional manufacturing industry, the higher pressure will be found in logistics industry. This paper analyzes the driving forces of 3PLs (Third Party Logistics) innovation. Basing on the literature review, a general analytical framework presented which includes the internal and external driving force. Connected

Xin Liu

2012-01-01

138

Forces and Interactions  

NSDL National Science Digital Library

Although the purist will state that there are four forces, when explaining observed phenomena at the nanoscale it is very useful to include interactions such as ionic and covalent bonding, hydrogen bonds, Brownian motion, van der Waals forces, thermal vibration, rotation , adhesive and cohesive forces and subcategories of these interactions. Often, the effect of what is observed at any scale (macroscale to nanoscale) is dependent upon the priorities of these forces. For example the interaction between planets is driven by the gravitational force because of the large mass of the objects, The strength of the interaction of planets due to the electrostatic forces exists, but is very small -- overshadowed by the gravitational forces. The opposite is often true at the nanoscale, atoms and molecules are significantly impacted by electrostatic forces - and because of the small mass, minimally impacted by gravitational attraction. So it is just a matter of which force or interaction is the top interaction for any given situation. These modules use many different activities which allow students to evaluate the priority of different forces and interactions with different materials and at different scales.

2012-10-04

139

Tactical force protection  

NASA Astrophysics Data System (ADS)

The need for enhanced tactical force protection capabilities is evidenced from our recent experiences in Iraq and Afghanistan and occurs wherever U.S. Forces maintain a forward presence in a potentially hostile environment. Levels of force protection proficiency vary widely from combat units whose mission is to close with and destroy the enemy to combat support/combat service support units performing maintenance and logistics functions. We must provide force protection capabilities that are not only good enough to get the job done, but affordable for the entire force. Addressing the force protection challenge requires an investment in research and development to deliver affordable, scalable, modular and sustainable force protection equipment. This can be accomplished through an evolutionary acquisition strategy of capability upgrades in the near, mid and far-terms that leverage the Army's investments in unmanned ground sensors (UGS), unmanned ground vehicles (UGV) and surveillance radar and imaging technology. This approach addresses the field's immediate tactical force protection requirements, while working towards full integration with the Future Combat System. Futuristic Tactical Force Protection will consist of a fully integrated system of systems architecture that will include UGVs, UGS and Unmanned Aerial Vehicles (UAVs) that are networked with the Future Force.

Stockel, Eugene; Moneyhun, Jon C.

2004-09-01

140

Do novel gravitational environments alter the grip-force/load-force coupling at the fingertips?  

PubMed

In this experiment we examined the coupling between grip force and load force observed during cyclic vertical arm movements with a hand-held object, performed in different gravitational environments. Six subjects highly experienced in parabolic flight participated in this study. They had to continuously move a cylindrical object up and down in the different gravity fields (1g, 1.8 g and 0 g) induced by parabolic flights. The imposed movement frequency was 1 Hz, the object mass was either 200 or 400 g, the amplitude of movement was either 20 or 40 cm and an additional mass of 200 g could be wound around the forearm. Each subject performed the task during 15 consecutive parabolas. The coordination between the grip force normal to the surface and the tangential load force was examined in nine loading conditions. We observed that the same normal grip force was used for equivalent loads generated by changes of mass, gravity or acceleration despite the fact that these loads required different motor commands to move the arm. Moreover, our results suggest that the gravitational and inertial components of the load are treated adequately and independently by the internal models used to predictively control the required grip force. These results indicate that the forward internal models used to control precision grip take into account the dynamic characteristics of the upper limb, the object and the environment to predict the object's acceleration and, in turn, the load force acting at the fingertips. PMID:15635455

White, Olivier; McIntyre, Joseph; Augurelle, Anne-Sophie; Thonnard, Jean-Louis

2005-06-01

141

77 FR 9267 - Child Labor, Forced Labor, and Forced or Indentured Child Labor in the Production of Goods in...  

Federal Register 2010, 2011, 2012, 2013

...manufactured with forced or indentured child labor (66 FR 5353). In addition...Certification as to Forced or Indentured Child Labor,'' which provide for...internationally recognized worker rights include ``findings by the...eliminate the worst forms of child labor.'' Title II of...

2012-02-16

142

77 FR 70473 - Child Labor, Forced Labor, and Forced or Indentured Child Labor in the Production of Goods in...  

Federal Register 2010, 2011, 2012, 2013

...manufactured with forced or indentured child labor (66 FR 5353). In addition...Certification as to Forced or Indentured Child Labor,'' which provide for...internationally recognized worker rights include ``findings by the...eliminate the worst forms of child labor.'' Title II of...

2012-11-26

143

78 FR 72714 - Child Labor, Forced Labor, and Forced or Indentured Child Labor in the Production of Goods in...  

Federal Register 2010, 2011, 2012, 2013

...manufactured with forced or indentured child labor (66 FR 5353). In addition...Certification as to Forced or Indentured Child Labor,'' which provide for...internationally recognized worker rights include ``findings by the...eliminate the worst forms of child labor.'' Title II of...

2013-12-03

144

Forced desorption of polymers from interfaces  

NASA Astrophysics Data System (ADS)

In the past decade it has become possible to directly measure the adsorption force of a polymer in contact with a solid surface using single-molecule force spectroscopy. A plateau force in the force-extension curve is often observed in systems of physisorbed or noncovalently bonded polymers. If a molecule is pulled quickly compared to internal relaxation, then nonequilibrium effects can be observed. Here we investigate these effects using statistical mechanical models and experiments with a spider silk polypeptide. We present evidence that most experiments showing plateau forces are done out of equilibrium. We find that the dominant nonequilibrium effect is that the detachment height hmax(v) increases with pulling speed v. Based on a nonequilibrium model within a master-equation approach, we show the sigmoidal dependence of the detachment height on the pulling speed of the cantilever, agreeing with experimental data on a spider silk polypeptide. We also show that the slope with which the plateau forces detach is given by the cantilever force constant in both theory and experiment.

Staple, Douglas B.; Geisler, Michael; Hugel, Thorsten; Kreplak, Laurent; Jrgen Kreuzer, Hans

2011-01-01

145

Internal Bleeding  

MedlinePLUS

... Caregivers > Injuries and Poisoning > First Aid 4 Internal Bleeding Heavy internal bleeding may occur in the abdominal cavity, chest cavity, ... femur) and pelvis, that are broken. Initially, internal bleeding may cause no symptoms, although an injured organ ...

146

Air Force Link  

NSDL National Science Digital Library

Appropriately enough, this website is "dedicated to the men and women who made the U.S. Air Force what it is today." As an official website of the United States Air Force, the Air Force Link Heritage website presents a wide range of materials that detail the history of this division of the Armed Forces. Here visitors will find a "This Week in History" feature which presents summary details of important events in the organization's past, such as the dates of important test flights and important air battles. Within the "Categories" area, visitors can delve into Air Force history. Neatly divided into decades, each section allows visitors to view photographs of important persons in the Air Force during the period, along with documents that relate various aspects of the group's history. Finally, the site also contains a set of links to other useful sites, such as the American Airpower Heritage Museum and the National Museum of Naval Aviation.

147

Coulomb Force as an Entropic Force  

E-print Network

Motivated by Verlinde's theory of entropic gravity, we give a tentative explanation to Coulomb's law with an entropic force. When trying to do this, we find the equipartition rule should be extended to charges and the concept of temperature should be reinterpreted. If one accepts the holographic principle as well as our generalizations and reinterpretations, then Coulomb's law, the Poisson equation and the Maxwell equations can be derived smoothly. Our attempt can be regarded as a new way to unify the electromagnetic force with gravity, from the entropic origin. Possibly some of our postulates are related to the D-brane picture of black hole thermodynamics.

Tower Wang

2010-05-17

148

Debunking Coriolis Force Myths  

NASA Astrophysics Data System (ADS)

Much has been written and debated about the Coriolis force.1-8 Unfortunately, this has done little to demystify the paradoxes surrounding this fictitious force invoked by an observer in a rotating frame of reference. It is the purpose of this article to make another valiant attempt to slay the dragon of the Coriolis force! This will be done without unleashing the usual mathematical apparatus, which we believe is more of a hindrance than a help.

Shakur, Asif

2014-11-01

149

Acoustic force spectroscopy.  

PubMed

Force spectroscopy has become an indispensable tool to unravel the structural and mechanochemical properties of biomolecules. Here we extend the force spectroscopy toolbox with an acoustic manipulation device that can exert forces from subpiconewtons to hundreds of piconewtons on thousands of biomolecules in parallel, with submillisecond response time and inherent stability. This method can be readily integrated in lab-on-a-chip devices, allowing for cost-effective and massively parallel applications. PMID:25419961

Sitters, Gerrit; Kamsma, Douwe; Thalhammer, Gregor; Ritsch-Marte, Monika; Peterman, Erwin J G; Wuite, Gijs J L

2015-01-01

150

Relativistic Linear Restoring Force  

ERIC Educational Resources Information Center

We consider two different forms for a relativistic version of a linear restoring force. The pair comes from taking Hooke's law to be the force appearing on the right-hand side of the relativistic expressions: d"p"/d"t" or d"p"/d["tau"]. Either formulation recovers Hooke's law in the non-relativistic limit. In addition to these two forces, we

Clark, D.; Franklin, J.; Mann, N.

2012-01-01

151

Central Force JS Model  

NSDL National Science Digital Library

The Central Force JavaScript Model computes the trajectory of a particle acted on by a central force.  The model reads uses a JavaScript mathematical expression parser to read the force and a adaptive step Runge-Kutta 5(4) algorithm to compute the trajectory.  This model is designed to test the speed of the JS parser and the accuracy of the EJS JavaScript ODE solver. The Central Force JS Model was developed using the Easy Java Simulations (EJS) version 5. It is distributed as a ready-to-run html page and requires only a browser with JavaScript support.

Christian, Wolfgang

2013-09-01

152

32 CFR 536.106 - Definitions for international agreements claims.  

Code of Federal Regulations, 2010 CFR

...Cognizable Under International Agreements 536.106 Definitions for international agreements claims. (a) Force...Types of claims under agreements (1) Intergovernmental...services may be asserted. NATO SOFA, Article...

2010-07-01

153

Climate forcings and feedbacks  

NASA Technical Reports Server (NTRS)

Global temperature has increased significantly during the past century. Understanding the causes of observed global temperature change is impossible in the absence of adequate monitoring of changes in global climate forcings and radiative feedbacks. Climate forcings are changes imposed on the planet's energy balance, such as change of incoming sunlight or a human-induced change of surface properties due to deforestation. Radiative feedbacks are radiative changes induced by climate change, such as alteration of cloud properties or the extent of sea ice. Monitoring of global climate forcings and feedbacks, if sufficiently precise and long-term, can provide a very strong constraint on interpretation of observed temperature change. Such monitoring is essential to eliminate uncertainties about the relative importance of various climate change mechanisms including tropospheric sulfate aerosols from burning of coal and oil smoke from slash and burn agriculture, changes of solar irradiance changes of several greenhouse gases, and many other mechanisms. The considerable variability of observed temperature, together with evidence that a substantial portion of this variability is unforced indicates that observations of climate forcings and feedbacks must be continued for decades. Since the climate system responds to the time integral of the forcing, a further requirement is that the observations be carried out continuously. However, precise observations of forcings and feedbacks will also be able to provide valuable conclusions on shorter time scales. For example, knowledge of the climate forcing by increasing CFC's relative to the forcing by changing ozone is important to policymakers, as is information on the forcing by CO2 relative to the forcing by sulfate aerosols. It will also be possible to obtain valuable tests of climate models on short time scales, if there is precise monitoring of all forcings and feedbacks during and after events such as a large volcanic eruption or an El Nino.

Hansen, James

1993-01-01

154

Internal stresses in molecules  

Microsoft Academic Search

Earlier work on internal stresses in one-electron systems is now extended to many-electron systems. The expressions for local stresses and local force densities involve electrostatic fields arising from given electronic and nuclear charge distributions and, therefore, the stress at any point in 3-D space again assumes a maxwellian form. As an illustration of the stress formalism, the interaction between two

B. M. Deb; Anjuli S. Bamzai

1979-01-01

155

Force networks and elasticity in granular silos.  

PubMed

We have made experimental observations of the force networks within a two-dimensional granular silo similar to the classical system of Janssen. Models like that of Janssen predict that pressure within a silo saturates with depth as the result of vertical forces being redirected to the walls of the silo where they can then be carried by friction. We use photoelastic particles to obtain information not available in previous silo experiments --the internal force structure. We directly compare various predictions with the results obtained by averaging ensembles of experimentally obtained force networks. We identify several differences between the mean behavior in our system and that predicted by Janssen-like models: We find that the redirection parameter describing how the force network transfers vertical forces to the walls varies with depth. We find that changes in the preparation of the material can cause the pressure within the silo to either saturate or to continue building with depth. Most strikingly, we observe a nonlinear response to overloads applied to the top of the material in the silo. For larger overloads we observe the previously reported "giant overshoot" effect where overload pressure decays only after an initial increase (G. Ovarlez et al., Phys. Rev. E 67, 060302(R) (2003)). For smaller overloads we find that additional pressure propagates to great depth. Analysis of the differences between the inter-grain contact and force networks suggests that, for our system, when the load and the particle weight are comparable, particle elasticity acts to stabilize the force network, allowing deep propagation. For larger loads, the force network rearranges, resulting in the expected, Janssen-like behavior. Thus, a meso-scale network phenomenon results in an observable nonlinearity in the mean pressure profile. PMID:20582447

Wambaugh, J F; Hartley, R R; Behringer, R P

2010-06-01

156

International Cooperation at NASA  

NASA Astrophysics Data System (ADS)

International cooperation is a cornerstone principle of NASAs activities, especially within the activities of the Science Mission Directorate. Nearly two thirds of the flight missions in which NASA leads or participates involve international cooperation. Numerous ground based activities also rely on international cooperation, whether because of unique expertise, unique geography, or the need for a global response. Going forward, in an era of tighter budgets and a more integrated global perspective, NASA and the rest of the space agencies around the world will be forced to work more closely together, in a broader array of activities than ever before, in order to be able to afford to push the boundaries of space exploration. The goal of this presentation is to provide an overview of NASAs current international science cooperative activities. It will include a discussion of why NASA conducts international cooperation and look at the mechanisms through which international cooperation can occur at NASA, including peer-to-peer development of relationships. It will also discuss some of the limiting factors of international cooperation, such as export control, and ways in which to manage those constraints. Finally, the presentation would look at some of the present examples where NASA is working to increase international cooperation and improve coordination. Case studies will be used to demonstrate these mechanisms and concepts. For example, NASA continues to participate in international coordination groups such as the International Mars Exploration Working Group (IMEWG) and International Space Exploration Coordination Group (ISECG), but is expanding into new areas as well. NASA is one of the leaders in expanding and improving international coordination in the area of Near-Earth Object detection, characterization, and mitigation. Having participated in the first meetings of such groups as the International Asteroid Warning Network (IAWN) and Space Missions Planning Advisory Group (SMPAG), NASA is placing an ever greater emphasis on sharing information among members and working to avoid duplication of effort for the betterment of all humanity. International cooperation at NASA takes many forms. In some cases NASA leads, while in other cases it follows the lead of our many international partners, all in the name of obtaining the best science. In many cases, truly stellar partnerships emerge. In a few cases, the partnership is ended before it can flourish. But in all cases, the partners are learning to work more closely together so that in the future, our partnerships will yield ever better results.

Tawney, Timothy; Feldstein, Karen

157

A White Paper on the medical and social needs of people with epilepsy and intellectual disability: The Task Force on Intellectual Disabilities and Epilepsy of the International League Against Epilepsy.  

PubMed

This White Paper builds on the publication of the International League Against Epilepsy (ILAE) and International Bureau for Epilepsy (IBE) report "Listening for a change-medical and social needs of people with intellectual disability who have epilepsy" (Listening for a change the medical and social needs of people with epilepsy and intellectual disability, ILAE, 2013). The Paper presents an overview of the recommendations of the report, which aim to improve the health and social care of this important population of people with epilepsy worldwide. Actions in four domains are indicated: (1) the development of standards and initiatives that would enhance diagnosis, pathways to investigation, and treatment; (2) the development of guidelines for treatment, specifically best practice in the management of antiepileptic drugs including rescue medication; (3) the development of standards for primary care, multidisciplinary teamwork, and clinical consultations, with emphasis on the need to enhance communication and improve access to information; and (4) the enhancement of links among different stakeholders including medical services, educational establishments, employment services, organizations providing opportunities for social engagement, and family members. The breadth of needs of this population is a challenge to the epilepsy world, spanning all the professional groupings, care providers, and the research modalities in epilepsy. PMID:25378101

Kerr, Mike; Linehan, Christine; Thompson, Rose; Mula, Marco; Gil-Nagal, Antonio; Zuberi, Sameer M; Glynn, Mike

2014-12-01

158

Elementary Particles and Forces.  

ERIC Educational Resources Information Center

Discusses subatomic particles (quarks, leptons, and others) revealed by higher accelerator energies. A connection between forces at this subatomic level has been established, and prospects are good for a description of forces that encompass binding atomic nuclei. Colors, fundamental interactions, screening, camouflage, electroweak symmetry, and

Quigg, Chris

1985-01-01

159

Physclips: Coriolis Forces  

NSDL National Science Digital Library

This web page provides an introduction to coriolis forces. It includes topics such as the motion of wind and ocean currents, the rotation of the Earth, and forces. Diagrams are integrated with text to promote understanding of important concepts. This tutorial is part of the PhysClip collection of web-based resources on introductory mechanics, electricity, and magnetism.

Wolfe, Joe

2009-06-18

160

Understanding Force and Motion  

NSDL National Science Digital Library

The objects will not change position from their initial rest positions because the downward force on each side of the pulley (ignoring the weight of the string) is the same and the net force on each side of the pulley is zero. The gravitational attraction

Haysom, John; Bowen, Michael

2010-10-01

161

Force, mass and acceleration  

Microsoft Academic Search

Force, mass and acceleration are everyday words but often used inaccurately. Force is a physical influence, which when applied to an object causes it to accelerate in the direction from which it was applied. Mass is the amount of matter in an object and is expressed in kilograms. Acceleration is the rate of change of velocity of an object in

Phil Dalrymple; Richard Griffiths

2005-01-01

162

NTNU Java: Frictional force  

NSDL National Science Digital Library

This applet illustrates the effect of frictional forces on the motion of masses. In this experiment, two masses, resting one on top of the other, are pulled by a hanging mass connected by an ideal rope. Masses and friction can be changed. Different force vectors are color-coded.

Hwang, Fu-Kwun

2004-12-18

163

Forces in yeast flocculation  

NASA Astrophysics Data System (ADS)

In the baker's yeast Saccharomyces cerevisiae, cell-cell adhesion (``flocculation'') is conferred by a family of lectin-like proteins known as the flocculin (Flo) proteins. Knowledge of the adhesive and mechanical properties of flocculins is important for understanding the mechanisms of yeast adhesion, and may help controlling yeast behaviour in biotechnology. We use single-molecule and single-cell atomic force microscopy (AFM) to explore the nanoscale forces engaged in yeast flocculation, focusing on the role of Flo1 as a prototype of flocculins. Using AFM tips labelled with mannose, we detect single flocculins on Flo1-expressing cells, showing they are widely exposed on the cell surface. When subjected to force, individual Flo1 proteins display two distinct force responses, i.e. weak lectin binding forces and strong unfolding forces reflecting the force-induced extension of hydrophobic tandem repeats. We demonstrate that cell-cell adhesion bonds also involve multiple weak lectin interactions together with strong unfolding forces, both associated with Flo1 molecules. Single-molecule and single-cell data correlate with microscale cell adhesion behaviour, suggesting strongly that Flo1 mechanics is critical for yeast flocculation. These results favour a model in which not only weak lectin-sugar interactions are involved in yeast flocculation but also strong hydrophobic interactions resulting from protein unfolding.

El-Kirat-Chatel, Sofiane; Beaussart, Audrey; Vincent, Stphane P.; Abelln Flos, Marta; Hols, Pascal; Lipke, Peter N.; Dufrne, Yves F.

2015-01-01

164

Forces in yeast flocculation.  

PubMed

In the baker's yeast Saccharomyces cerevisiae, cell-cell adhesion ("flocculation") is conferred by a family of lectin-like proteins known as the flocculin (Flo) proteins. Knowledge of the adhesive and mechanical properties of flocculins is important for understanding the mechanisms of yeast adhesion, and may help controlling yeast behaviour in biotechnology. We use single-molecule and single-cell atomic force microscopy (AFM) to explore the nanoscale forces engaged in yeast flocculation, focusing on the role of Flo1 as a prototype of flocculins. Using AFM tips labelled with mannose, we detect single flocculins on Flo1-expressing cells, showing they are widely exposed on the cell surface. When subjected to force, individual Flo1 proteins display two distinct force responses, i.e. weak lectin binding forces and strong unfolding forces reflecting the force-induced extension of hydrophobic tandem repeats. We demonstrate that cell-cell adhesion bonds also involve multiple weak lectin interactions together with strong unfolding forces, both associated with Flo1 molecules. Single-molecule and single-cell data correlate with microscale cell adhesion behaviour, suggesting strongly that Flo1 mechanics is critical for yeast flocculation. These results favour a model in which not only weak lectin-sugar interactions are involved in yeast flocculation but also strong hydrophobic interactions resulting from protein unfolding. PMID:25515338

El-Kirat-Chatel, Sofiane; Beaussart, Audrey; Vincent, Stphane P; Abelln Flos, Marta; Hols, Pascal; Lipke, Peter N; Dufrne, Yves F

2015-01-22

165

New force in nature  

SciTech Connect

We review recent experimental and theoretical work dealing with the proposed fifth force. Further analysis of the original Eoetvoes experiments has uncovered no challenges to our original assertion that these data evidence a correlation characteristic of the presence of a new coupling to baryon number or hypercharge. Various models suggest that the proposed fifth force could be accomodated naturally into the existing theoretical framework.

Fischbach, E.; Sudarsky, D.; Szafer, A.; Talmadge, C.; Aronson, S.H.

1986-10-15

166

Optical Measurement of Mechanical Forces Inside Short DNA Loops  

PubMed Central

Knowledge of the mechanical properties of double-stranded DNA (dsDNA) is essential to understand the role of dsDNA looping in gene regulation and the mechanochemistry of molecular machines that operate on dsDNA. Here, we use a newly developed tool, force sensors with optical readout, to measure the forces inside short, strained loops composed of both dsDNA and single-stranded DNA. By varying the length of the loops and their proportion of dsDNA, it was possible to vary their internal forces from 1 pN to >20 pN. Surprisingly, internal loop forces changed erratically as the amount of dsDNA was increased for a given loop length, with the effect most notable in the smallest loop (57 nucleotides). Monte Carlo simulations based on the helical wormlike chain model accurately predict internal forces when more than half of the loop is dsDNA but fail otherwise. Mismatches engineered into the double-stranded regions increased flexibility, suggesting that Watson-Crick basepaired dsDNA can withstand high compressive forces without recourse to multibase melts. Fluorescence correlation spectroscopy further excluded transient melting (microsecond to millisecond duration) as a mechanism for relief of compressive forces in the tested dsDNAs. DNA loops with integrated force sensors may allow the comprehensive mapping of the elasticity of short dsDNAs as a function of both sequence and salt. PMID:18065484

Shroff, Hari; Sivak, David; Siegel, Jake J.; McEvoy, A. L.; Siu, Merek; Spakowitz, Andrew; Geissler, Phillip L.; Liphardt, Jan

2008-01-01

167

Plasma igniter for internal-combustion engines  

NASA Technical Reports Server (NTRS)

Hot ionized gas (plasma) ignites air/fuel mixture in internal combustion engines more effectively than spark. Electromagnetic forces propel plasma into combustion zone. Combustion rate is not limited by flame-front speed.

Breshears, R. R.; Fitzgerald, D. J.

1978-01-01

168

Turbomachinery rotor forces  

NASA Technical Reports Server (NTRS)

The fluid-induced forces, both steady and unsteady, acting upon an impeller of a centrifugal pump, and impeller blade-diffuser vane interaction in centrifugal pumps with vaned radial diffusers were evaluated experimentally and theoretically. Knowledge of the steady and unsteady forces, and the associated rotordynamic coefficients are required to effectively model the rotor dynamics of the High Pressure Fuel Turbopump (HPFTP) of the Space Shuttle Main Engine (SSME). These forces and rotordynamic coefficients were investigated using different impellers in combination with volutes and vaned diffusers, and axial inducers. These rotor forces are global. Local forces and pressures are also important in impeller-diffuser interaction, for they may cause cavitation damage and even vane failures. Thus, in a separate investigation, impeller wake, and impeller blade and diffuser vane pressure measurements were made. The nature of the rotordynamic forces is discussed, the experimental facility is described, and the measurements of unsteady forces and pressure are reported together with a brief and incomplete attempt to calculate these flows.

Arndt, Norbert

1988-01-01

169

Manual discrimination of force  

NASA Technical Reports Server (NTRS)

Optimal design of human-machine interfaces for teleoperators and virtual-environment systems which involve the tactual and kinesthetic modalities requires knowledge of the human's resolving power in these modalities. The resolution of the interface should be appropriately matched to that of the human operator. We report some preliminary results on the ability of the human hand to distinguish small differences in force under a variety of conditions. Experiments were conducted on force discrimination with the thumb pushing an interface that exerts a constant force over the pushing distance and the index finger pressing against a fixed support. The dependence of the sensitivity index d' on force increment can be fit by a straight line through the origin and the just-noticeable difference (JND) in force can thus be described by the inverse of the slope of this line. The receiver operating characteristic (ROC) was measured by varying the a priori probabilities of the two alternatives, reference force and reference force plus an increment, in one-interval, two-alternative, forced-choice experiments. When plotted on normal deviate coordinates, the ROC's were roughly straight lines of unit slope, thus supporting the assumption of equal-variance normal distributions and the use of the conventional d' measure. The JND was roughly 6-8 percent for reference force ranging from 2.5 to 10 newtons, pushing distance from 5 to 30 mm, and initial finger-span from 45 to 125 mm. Also, the JND remained the same when the subjects were instructed to change the average speed of pushing from 23 to 153 mm/sec. The pushing was terminated by reaching either a wall or a well, and the JND's were essentially the same in both cases.

Pang, Xiao-Dong; Tan, HONG-Z.; Durlach, Nathaniel I.

1991-01-01

170

Cellular control lies in the balance of forces Marina E Chicurel, Christopher S Chen and Donald E Ingber  

E-print Network

-directed forces are resisted by external adhesions to the ECM and to other cells, by internal molecular struts, at any point in time the cell exists in a state of isometric tension. To understand how mechanical forces

Chen, Christopher S.

171

Assessing the industry using Porter's five forces.  

PubMed

To develop a business and plan for the future, there is a need to assess the current situation. One way of doing this is to use Porter's five forces framework. This was the brainchild of Harvard Business School's Michael Porter and developed in 1979. Looking at the competitive intensity of an industry, the model assesses internal and external factors that act together to determine the direction of the business; taken together, this gives an indication of the attractiveness of the industry. PMID:24470612

2014-01-01

172

Reestablishing biologic width with forced eruption.  

PubMed

Maintenance of gingival health is one of the keys for the longevity of teeth, as well as for the longevity of restorations. In this context, the biologic width functions as a barrier against the entrance of microorganisms into the internal medium of the periodontal ligament and into the gingival and osseous connective tissue. This clinical case describes a technique to reestablish the biologic width of a central incisor using forced extrusion and done without post-treatment corrective surgery. PMID:14620262

Felippe, Lus Antonio; Monteiro Jnior, Sylvio; Vieira, Luis Clovis Cardoso; Araujo, Elito

2003-01-01

173

Trends of Measured Climate Forcing Agents  

NASA Technical Reports Server (NTRS)

The growth rate of climate forcing by measured greenhouse gases peaked near 1980 at almost 5 W/sq m per century. This growth rate has since declined to approximately equal to 3 W/sq m per century, largely because of cooperative international actions. We argue that trends can be reduced to the level needed for the moderate "alternative" climate scenario (approximately equal to 2 W/M2 per century for the next 50 years) by means of concerted actions that have other benefits, but the forcing reductions are not automatic "co-benefits" of actions that slow CO2 emissions. Current trends of climate forcings by aerosols remain very uncertain. Nevertheless, practical constraints on changes in emission levels suggest that global warming at a rate + 0.15 +/- 0.05 C per decade will occur over the next several decades.

Hansen, James E.; Sato, Makiko; Einaudi, Franco (Technical Monitor)

2002-01-01

174

Future trends in international migration to Europe.  

PubMed

The author discusses future trends in international migration to Europe, with a focus on the impact of the economic situation on labor force needs and resources. Aspects considered include changes in foreign direct investments, changes in the size of the European labor market, and the potential emigration of the labor force in underdeveloped countries. PMID:12287572

Verhaeren, R

1993-01-01

175

International social development and counter-development  

Microsoft Academic Search

International development theory and practice tend to emphasize the importance of optimizing development inputs such as capital, infrastructure, and expertise. Equally important in the success of development is the mitigation of counter-development forces such as corruption, rent-seeking, terrorism and organized crime. This article presents a development model that incorporates those forces that impede development.

Mark Lusk

2010-01-01

176

Motion and Forces  

NSDL National Science Digital Library

This self-contained module on motion and forces includes a range of fun activities that students can perform in the classroom and at home with family members. They impart important concepts such as observation, identification, measurement, and differentiation.

Houghton Mifflin Science

177

Causal reasoning with forces  

PubMed Central

Causal composition allows people to generate new causal relations by combining existing causal knowledge. We introduce a new computational model of such reasoning, the force theory, which holds that people compose causal relations by simulating the processes that join forces in the world, and compare this theory with the mental model theory (Khemlani et al., 2014) and the causal model theory (Sloman et al., 2009), which explain causal composition on the basis of mental models and structural equations, respectively. In one experiment, the force theory was uniquely able to account for people's ability to compose causal relationships from complex animations of real-world events. In three additional experiments, the force theory did as well as or better than the other two theories in explaining the causal compositions people generated from linguistically presented causal relations. Implications for causal learning and the hierarchical structure of causal knowledge are discussed. PMID:25653611

Wolff, Phillip; Barbey, Aron K.

2015-01-01

178

Optical Bernoulli forces  

E-print Network

By Bernoulli's law, an increase in the relative speed of a fluid around a body is accompanied by a decrease in the pressure. Therefore, a rotating body in a fluid stream experiences a force perpendicular to the motion of ...

Movassagh, Ramis

179

Constraint and Restoring Force  

E-print Network

Long-lived sensor network applications must be able to self-repair and adapt to changing demands. We introduce a new approach for doing so: Constraint and Restoring Force. CRF is a physics-inspired framework for computing ...

Beal, Jacob

2007-08-24

180

Chemical force microscopy  

NASA Astrophysics Data System (ADS)

This thesis describes principles and applications of Chemical Force Microscopy (CFM)-a novel scanning probe microscopy technique that allows direct probing of intermolecular interactions and imaging with chemical sensitivity. Probe tips of an atomic force microscope were modified with self-assembled monolayers (SAMs) that terminated in a variety of terminal chemical functionalities. Use of these tips allowed to measure and quantify adhesion and friction forces between the functional groups on the tip and on the sample. Adhesion force studies between SAMs that terminate with hydrogen-bonding and hydrophobic functional groups have shown that CFM can reproducibly distinguish between different types of intermolecular interactions. The trends observed in these experiments follow chemical intuition and can be interpreted based on modern theory of contact mechanics. This theory also allowed to show that the contact area between the sharp (<50 nm) tips and the sample corresponds to an interaction between only 15-25 molecular pairs. CFM measurements used in the context of contact mechanics model can provide values of surface free energies for solid-liquid interfaces and solid-solid interfacial free energies. A new method-force titrations-has been developed to study surface ionization and determine local pK values. The interactions observed between tip and sample surfaces modified with ionizable functional groups in aqueous solutions also agree with predictions of double-layer and modified JKR models. CFM measurements have been used to extract double layer parameters that are essential to understanding interactions in aqueous media. CFM allowed to observe chemical specificity in friction forces. The magnitude of the friction forces follows the same trend as adhesion forces. The predictable dependence of the friction forces on the tip and sample functionality has been exploited for mapping surface domains of different functional groups with chemical sensitivity. It has been demonstrated that lateral force images can be rationally interpreted in terms of the strength of the interactions between functional groups on the probe and on the surface. It is also shown that CFM approach can be extended to imaging in tapping mode, which opens us possibilities for chemically-sensitive imaging of soft and delicate surfaces of polymers and biological objects. Chemical force microscopy has been also extended to a realm of complex interactions relevant to biophysics. Development of appropriate attachment chemistry enabled direct measurements of forces necessary to elastically stretch, structurally transform and break apart a single DNA duplex formed from short (14 base pair) synthetic oligonucleotides. Complementary and non-complementary sequences can be reproducibly distinguished on the basis of the differences in binding forces. Force microscopy and DNA synthesis can now be used to study the effect of specific DNA sequences on forces and the binding in the presence and absence of DNA binding proteins and molecules. These studies show that chemical force microscopy represents a practical and versatile approach to studying various aspects of intermolecular interactions and mapping surface functional groups on a nanometer scale.

Noy, Aleksandr

181

Weak nuclear forces cause the strong nuclear force  

E-print Network

We determine the strength of the weak nuclear force which holds the lattices of the elementary particles together. We also determine the strength of the strong nuclear force which emanates from the sides of the nuclear lattices. The strong force is the sum of the unsaturated weak forces at the surface of the nuclear lattices. The strong force is then about ten to the power of 6 times stronger than the weak force between two lattice points.

E. L. Koschmieder

2007-12-11

182

New force in nature  

SciTech Connect

We review recent experimental and theoretical work dealing with the proposed fifth force. Further analysis of the original Eotvos experiments has uncovered no challenges to our original assertion that these data evidence a correlation characteristic of the presence of a new coupling to baryon number or hypercharge. Various models suggest that the proposed fifth force could be accommodated naturally into the existing theoretical framework. 40 refs.

Fischbach, E.; Sudarsky, D.; Szafer, A.; Talmadge, C.; Aronson, S.H.

1986-01-01

183

Metamaterials enhancing optical forces  

NASA Astrophysics Data System (ADS)

The interaction between light and matter involves not only an energy transfer, but also the transfer of linear momentum. In everyday life applications this linear momentum of light is too small to play any significant role. However, in nanoscale dimensions, the associated optical forces start to play an increasingly important role. These forces are, e.g., large enough for exiting experiments in the fields of cavity-optomechanics, laser cooling and optical trapping of small particles. Recently, it has been suggested that optical gradient forces can also be employed for all-optical actuation in micro- and nanophotonic systems. The typical setup consists of two slab waveguides positioned in each others vicinity such that they are coupled through the interaction of the evanescent tails. Although the gradient forces between these waveguides can be enhanced considerably using electromagnetic resonators or slow-light techniques, the resulting displacements remain relatively small. In this contribution, we present an alternative approach to enhance optical gradient forces between waveguides using a combination of transformation optics and metamaterials. Our design starts from the observation that gradient forces exponentially decay with the separation distance between the waveguides. Therefore, we employ transformation optics to annihilate the apparent distance for light between the waveguides. Analytical calculations confirm that the resulting forces indeed increase when such an annihilating cladding is inserted. Subsequently, we discuss the metamaterial implementation of this annihilating medium. Such lensing media automatically translate into anisotropic metamaterials with negative components in the permittivity and permeability tensors. Our full-wave numerical simulations show that the overall amplification is highly limited by the loss-tangent of the metamaterial cladding. However, as this cladding only needs to operate in the near-field for a specific polarization, we can also consider single-negative metamaterial implementations. We finally demonstrate that in this way metamaterials can support optical forces enhanced by more than 200 times [Phys. Rev. Lett. 110, 057401 (2013)].

Ginis, Vincent; Tassin, Philippe; Soukoulis, Costas M.; Veretennicoff, Irina

2014-05-01

184

Force user's manual, revised  

NASA Technical Reports Server (NTRS)

A methodology for writing parallel programs for shared memory multiprocessors has been formalized as an extension to the Fortran language and implemented as a macro preprocessor. The extended language is known as the Force, and this manual describes how to write Force programs and execute them on the Flexible Computer Corporation Flex/32, the Encore Multimax and the Sequent Balance computers. The parallel extension macros are described in detail, but knowledge of Fortran is assumed.

Jordan, Harry F.; Benten, Muhammad S.; Arenstorf, Norbert S.; Ramanan, Aruna V.

1987-01-01

185

A simple force platform.  

PubMed

The force platform consists of a sandwhich of steel, Rockwool and concrete plates about 900 X 700 mm in surface. Four steel rings were bolted to the under side of the steel plate in each corner. Each steel ring was furnished with only one strain gauge, two of which were placed on the outer- respectively on the inner side of each ring. The four strain gauges were connected to a measuring bridge. Before mounting the rings on the steel plate, the sensitivity to pressure of each ring was adjusted in such a way that they were all similar. Because of this the platform responded with a signal which was independent of where a pressure was applied within the surface of the platform. The platform showed a rectilinear response for static forces up to 500 kp with a stable zero value. In response to dynamic forces the platform showed a resononance frequency of about 50 Hz, with a damping factor of 0.15. Calibration of dynamic forces was carried out by calculation of the forces during a vertical jump compared with what would be expected from the time of flight also registered by the platform-measuring-bridge-ink-writer-set-up. The time of flight was significantly higher (11%) than exected from the time-force relations beforetake-off. This was esplained partly by the relatively low damping factor in the system, partly by the subjects not extending their knees at landing on the platform. PMID:1149732

Bonde-Petersen, F

1975-01-01

186

Eighth International Forum State, Civil Society and Business Partnership  

E-print Network

Influencing the Definition of Cyber "War" 8. Laurent Gisel (International Committee of the Red Cross) "Adaptation of international law to cyber conflict" 10. Akira Kato (Liberal Arts College of Obirin University, Japan) "The Concept of "Force" and "Threat or Use of Force" 11. B.Miroshnikov (CyberPlat, Russia) "Law

Kaplan, Alexander

187

Forced response of a laminar shock-induced separation bubble  

NASA Astrophysics Data System (ADS)

The source of unsteadiness in shock-wave/boundary-layer interactions is currently disputed. This paper considers a two-dimensional separation bubble induced by an oblique shock wave interacting with a laminar boundary layer at a free-stream Mach number of 1.5. The global response of the separated region to white noise forcing is analyzed for different interaction strengths, which generate small and large separation bubbles. Forcing location and amplitude effects have been examined. For both interaction strengths and for forcing both upstream and inside the bubble, the wall-pressure spectra downstream of the separation show a high-frequency peak that is demonstrated to be a Kelvin-Helmholtz instability. A low-frequency response at the separation point is also found when the separation bubble is only forced internally, therefore with a disturbance-free upstream boundary layer. For low-amplitude internal forcing, the low-frequency response at the separation point and downstream of the bubble is linear. However, when forced upstream the low-frequency unsteadiness of the large separation bubble is found to be driven by nonlinearities coming from the downstream shedding. The same nonlinear behavior is found when the separation bubble is internally forced over a narrow band around the shedding frequency, without low-frequency disturbances. This analysis for a laminar interaction is used to interpret the low-frequency unsteadiness found at the foot of the shock of turbulent interactions. Here, the low-frequency unsteadiness occurs in the absence of upstream disturbances and a linear relationship is found between the internal forcing and the response near the separation point. When low-frequencies are not present in the forcing they are generated from weak nonlinearities of the shear-layer instability modes.

Sansica, A.; Sandham, N. D.; Hu, Z.

2014-09-01

188

On The 5D Extra-Force according to Basini-Capozziello-Ponce De Leon Formalism and the Experimental Research of Extra Dimensions On-Board International Space Station(ISS) using Laser Beams  

E-print Network

We analyze the possibility of Experimental Research of Extra Dimensions On-Board International Space Station (ISS) by using a Satellite carrying a Laser device(optical Laser) on the other side of Earth Orbit targeted towards ISS.The Sun will be between the Satellite and the ISS so the Laser will pass the neighborhoods of the Sun at a distance $R$ in order to reach ISS. The Laser beam will be Gravitationally Bent according to Classical General Relativity and the Extra Terms predicted by Kar-Sinha in the Gravitational Bending Of Light due to the presence of Extra Dimensions can perhaps be measured with precision equipment.By computing the Gravitational Bending according to Einstein we know the exact position where the Laser will reach the target on-board ISS.However if the Laser arrives at ISS with a Bending different than the one predicted by Einstein and if this difference is equal to the Extra Terms predicted by Kar-Sinha then this experience would proof that we live in a Universe of more than 4 Dimensions.We demonstrate in this work that ISS have the needed precision to detect these Extra Terms(see eq 137 in this work).Such experience would resemble the measures of the Gravitational Bending Of Light by Sir Arthur Stanley Eddington in the Sun Eclipse of 1919 that helped to proof the correctness of General Relativity although in ISS case would have more degres of accuracy because we would be free from the interference of Earth Atmosphere.

Fernando Loup

2007-10-04

189

ENGINEERING INTERNATIONAL  

E-print Network

COURSE GUIDE 2013 UTS: ENGINEERING INTERNATIONAL UNDERGRADUATE w w w.eng.uts.edu.au #12;2 / ENGINEERING IN AUSTRALIA Internationally, Australian universities have a reputation for high quality research developed close links with many international institutions, particularly in Asia. ENGINEERING IN SYDNEY

University of Technology, Sydney

190

Measurement and stochastic modeling of kidney puncture forces.  

PubMed

The development of needle insertion robots and training simulators requires knowledge of the forces that arise when a needle is inserted into soft-tissue. The present study aims to construct stochastic models of the force required to puncture a kidney using a trocar needle, based on measurements. To this end, a total of sixty insertions were performed into porcine kidneys (ex vivo), at constant speed, using a linear motion stage. Axial force was measured at the needle hub and an ultrasound probe moved with the needle to enable identification of anatomical structures. Two force peaks were observed for each tissue layer punctured, one caused by the tip and one by the edge of the cannula. Based on ultrasound data these double-peaks were classified into four groups, related to kidney capsule and internal structures. Group size varied from 7 to 55 double-peaks. Force peaks in each group were evaluated in terms of peak force and drop in force for both tip and cannula, and stochastic models were constructed that describe the multivariate distribution of these metrics. Peak forces in the capsule and internal structures ranged up to 2 N and 8 N, respectively. The resulting models can be used to simulate kidney puncture events in a variety of applications. PMID:24129753

van Gerwen, D J; Dankelman, J; van den Dobbelsteen, J J

2014-03-01

191

Surgical force detection probe  

NASA Technical Reports Server (NTRS)

The development progress of a precision electro-mechanical instrument which allows the detection and documentation of the forces and moment applied to human tissue during surgery (under actual operation room conditions), is reported. The pen-shaped prototype probe which measures 1/2 inch in diameter and 7 inches in length was fabricated using an aerodynamic balance. The aerodynamic balance, a standard wind tunnel force and moment sensing transducer, measures the forces and the moments transmitted through the surgeon's hand to the human tissue during surgery. The prototype probe which was fabricated as a development tool was tested successfully. The final version of the surgical force detection probe will be designed based on additional laboratory tests in order to establish the full scale loads. It is expected that the final product will require a simplified aerodynamic balance with two or three force components and one moment component with lighter full scale loads. A signal conditioner was fabricated to process and display the outputs from the prototype probe. This unit will be interfaced with a PC-based data system to provide automatic data acquisition, data processing, and graphics display. The expected overall accuracy of the probe is better than one percent full scale.

Tcheng, Ping; Roberts, Paul; Scott, Charles; Prass, Richard

1991-01-01

192

BME 315 Biomechanics Foot force measurement by a force platform  

E-print Network

be walking (Fig. 1). The landing and push-off phases of walking each have a vertical force component as well is a very accurately machined rigid plate that is attached to 4 instrumented pedestals (Fig. 2). A load): Force plate coordinate system of the Bertec force plate in ME3034. III. Laboratory equipment The force

Lakes, Roderic

193

Weak Nuclear Forces cause the Strong Nuclear Force  

SciTech Connect

We determine the strength of the weak nuclear force which holds the lattices of the elementary particles together. We also determine the strength of the strong nuclear force which emanates from the sides of the nuclear lattices. The strong force is the sum of the unsaturated weak forces at the surface of the lattices.

Koschmieder, E. L. [Center for Statistical Mechanics, University of Texas at Austin, Austin TX 78712 (United States)

2008-05-29

194

Antiphospholipid Syndrome Clinical Research Task Force report.  

PubMed

The Antiphospholipid Syndrome (APS) Clinical Research Task Force (CRTF) was one of six Task Forces developed by the 13(th) International Congress on Antiphospholipid Antibodies (aPL) organization committee with the purpose of: a) evaluating the limitations of APS clinical research and developing guidelines for researchers to help improve the quality of APS research; and b) prioritizing the ideas for a well-designed multicenter clinical trial and discussing the pragmatics of getting such a trial done. Following a systematic working algorithm, the Task Force identified five major issues that impede APS clinical research and the ability to develop evidence-based recommendations for the management of aPL-positive patients: (1) aPL detection has been based on partially or non-standardized tests, and clinical (and basic) APS research studies have included patients with heterogeneous aPL profiles with different clinical event risks; (2) clinical (and basic) APS research studies have included a heterogeneous group of patients with different aPL-related manifestations (some controversial); (3) thrombosis and/or pregnancy risk stratification and quantification are rarely incorporated in APS clinical research; (4) most APS clinical studies include patients with single positive aPL results and/or low-titer aPL ELISA results; furthermore, study designs are mostly retrospective and not population based, with limited number of prospective and/or controlled population studies; and (5) lack of the understanding the particular mechanisms of aPL-mediated clinical events limits the optimal clinical study design. The Task Force recommended that there is an urgent need for a truly international collaborative approach to design and conduct well-designed prospective large-scale multi-center clinical trials of patients with persistent and clinically significant aPL profiles. An international collaborative meeting to formulate a good research question using 'FINER' (Feasible; Interesting; Novel; Ethical; and Relevant) criteria took place in November 2010. PMID:21303838

Erkan, D; Derksen, R; Levy, R; Machin, S; Ortel, T; Pierangeli, S; Roubey, R; Lockshin, M

2011-02-01

195

On The 5D Extra-Force according to Basini-Capozziello-Leon Formalism and five important features: Kar-Sinha Gravitational Bending of Light, Chung-Freese Superluminal Behaviour, Maartens-Clarkson Black Strings, Experimental measures of Extra Dimensions on board International Space Station(ISS) and the existence of the Particle $Z$ due to a Higher Dimensional spacetime  

E-print Network

We use the Conformal Metric as described in Kar-Sinha work on Gravitational Bending of Light in a 5D Spacetime to recompute the equations of the 5D Force in Basini-Capozziello-Leon Formalism and we arrive at a result that possesses some advantages. The equations of the Extra Force as proposed by Leon are now more elegant in Conformal Formalism and many algebraic terms can be simplified or even suppressed. Also we recompute the Kar-Sinha Gravitational Bending of Light affected by the presence of the Extra Dimension and analyze the Superluminal Chung-Freese Features of this Formalism describing the advantages of the Chung-Freese BraneWorld when compared to other Superluminal spacetime metrics(eg:Warp Drive) and we describe why the Extra Dimension is invisible and how the Extra Dimension could be made visible at least in theory.We also examine the Maartens-Clarkson Black Holes in 5D(Black Strings) coupled to massive Kaluza-Klein graviton modes predicted by Extra Dimensions theories and we study experimental detection of Extra Dimensions on-board LIGO and LISA Space Telescopes.We also propose the use of International Space Station(ISS) to measure the additional terms(resulting from the presence of Extra Dimensions) in the Kar-Sinha Gravitational Bending of Light in Outer Space to verify if we really lives in a Higher Dimensional Spacetime.Also we demonstrate that Particle $Z$ can only exists if the 5D spacetime exists.

Fernando Rego Loup

2006-03-28

196

The Force of Symmetry  

NASA Astrophysics Data System (ADS)

The Force of Symmetry gives an elementary introduction to the spectacular interplay among the three great themes of contemporary physics: quantum behavior, relativity, and symmetry. In clear, nontechnical language, it explores many fascinating aspects of modern physics, discussing the nature and interaction of force and matter. All these themes are drawn together toward the end of the book to describe the most successful physics theory in history, the "standard model" of subatomic particles. The book is suitable for undergraduate students in physics and mathematics.

Icke, Vincent

1995-02-01

197

Image Force Microscopy  

NASA Astrophysics Data System (ADS)

In this thesis we describe an enhancement to the Atomic force microscope (AFM) to simultaneously gather topographic features and spectroscopic information .Compared to the current state of the art of near-field excitation and far-field detection AFM imaging techniques our system uses a radical new approach near-field excitation and near-field detection. By placing the detector in the near-field we achieve high signal to noise and single molecular resolution. The origin of our near-field detector signal is the image force gradient due to the interaction of the stimulated molecular dipole with its image on the metal probe. We designed and built an optical and electronic system to capture this signal and simultaneously image nano-scale surface topography and optical image force gradient. By varying the wavelength of the excitation beam we measure the induced optical image force gradient spectra of molecules on surface. These spectra show good agreement with the absorption spectra of the bulk molecules measured by conventional absorption spectroscopy. We show that image force gradient is directly proportional to the optical absorption dipole strength. Using Finite Element 3D electromagnetic simulations and using Lorentz model for the excited molecular dipole we showed that the image force gradient has a decay length of 1nm, making the theoretical resolution of this microscopy technique approximately 1 nm. This rapid decay was measured experimentally .This resolution was seen by the high contrasting spectroscopic images of molecules on the surface. In follow on experiments this technique was extended to provide surface Raman spectroscopy and microscopy at molecular resolution. We create an image force gradient interaction through optical parametric down conversion between stimulated Raman excited molecules on a surface and a cantilevered nanometer scale probe brought very close to it. Spectroscopy and microscopy on clusters of molecules have been performed. Single molecules within such clusters are clearly resolved in the Raman micrographs. Raman spectra of amino acid Phenylalanine was obtained this the first time the Raman effect has been detected through a force interaction.

Rajapaksa, Indrajith

198

Radation force on a relativistic plasma and the Eddington limit  

Microsoft Academic Search

The Thomson-scattering radiation force on a hot isotropic exceeds that on a cold one by a factor of (2\\/3<(..gamma beta..)²>+1), where ..gamma.. = (1-..beta..²)⁻¹² is the electron Lorentz factor. This excess force results from the anisotropic loss of internal energy. Consequently, a relativistic plasma with <..gamma..²>>>5\\/2, when exposed to an anisotropic radiation field, acts as a rocket-a ''Compton rocket'', Compton

S. L. Odell

1981-01-01

199

Schooling, Labor-Force Quality, and the Growth of Nations  

Microsoft Academic Search

Direct measures of labor-force quality from international mathematics and science test scores are strongly related to growth. Indirect specification tests are generally consistent with a causal link: direct spending on schools is unrelated to student performance differences; the estimated growth effects of improved labor-force quality hold when East Asian countries are excluded; and, finally, home-country quality differences of immigrants are

Eric A. Hanushek; Dennis D. Kimko

2000-01-01

200

Probing cellular traction forces with magnetic nanowires and microfabricated force sensor arrays  

NASA Astrophysics Data System (ADS)

In this paper, the use of magnetic nanowires for the study of cellular response to force is demonstrated. High-aspect ratio Ni rods with diameter 300 nm and lengths up to 20 ?m were bound to or internalized by pulmonary artery smooth muscle cells (SMCs) cultured on arrays of flexible micropost force sensors. Forces and torques were applied to the cells by driving the nanowires with AC magnetic fields in the frequency range 0.1-10 Hz, and the changes in cellular contractile forces were recorded with the microposts. These local stimulations yield global force reinforcement of the cells traction forces, but this contractile reinforcement can be effectively suppressed upon addition of a calcium channel blocker, ruthenium red, suggesting the role of calcium channels in the mechanical response. The responsiveness of the SMCs to actuation depends on the frequency of the applied stimulation. These results show that the combination of magnetic nanoparticles and micropatterned, flexible substrates can provide new approaches to the study of cellular mechanotransduction.

Lin, Yi-Chia; Kramer, Corinne M.; Chen, Christopher S.; Reich, Daniel H.

2012-02-01

201

Models agree on forced response pattern of precipitation and temperature extremes  

NASA Astrophysics Data System (ADS)

projections of heavy precipitation and temperature extremes include large uncertainties. We demonstrate that the disagreement between individual simulations primarily arises from internal variability, whereas models agree remarkably well on the forced signal, the change in the absence of internal variability. Agreement is high on the spatial pattern of the forced heavy precipitation response showing an intensification over most land regions, in particular Eurasia and North America. The forced response of heavy precipitation is even more robust than that of annual mean precipitation. Likewise, models agree on the forced response pattern of hot extremes showing the greatest intensification over midlatitudinal land regions. Thus, confidence in the forced changes of temperature and precipitation extremes in response to a certain warming is high. Although in reality internal variability will be superimposed on that pattern, it is the forced response that determines the changes in temperature and precipitation extremes in a risk perspective.

Fischer, E. M.; Sedl?ek, J.; Hawkins, E.; Knutti, R.

2014-12-01

202

Pulleys and Force  

NSDL National Science Digital Library

In this activity, learners explore the concept of force and how pulleys are used in everyday life to make work easier. Learners examine different uses for pulleys, the impact of multiple pulleys, and identify pulley use in school and their community. Learners test the ability to move weights using one, two and three pulleys in a series.

IEEE

2013-08-30

203

Atomic force microscope  

Microsoft Academic Search

A scanning tunneling microscope (STM), which is capable of measuring forces as small as 10 to the -18th N, is described. Application of the STM to observations of insulator surfaces on the atomic scale is discussed in detail. The results of preliminary tests of the system indicate a lateral resolution of 30 A and a vertical resolution of less than

G. Binnig; C. F. Quate; Ch. Gerber

1986-01-01

204

Forces and Interactions  

NSDL National Science Digital Library

The content related to forces and interactions is important to most science disciplines. While chemistry is the most obvious place to introduce these ideas, it is important to connect aspects of this big idea to phenomena in biology, physics, and Earth sc

Joseph S. Krajcik

2009-10-14

205

Forces in Nonlinear Media  

E-print Network

I investigate the properties of forces on bodies in theories governed by the generalized Poisson equation div[mu(abs(grad_phi))grad_phi]=G rho, for the potential phi produced by a distribution of sources rho. This equation describes, inter alia, media with a response coefficient, mu, that depends on the field strength, such as in nonlinear, dielectric, or diamagnetic, media; nonlinear transport problems with field-strength dependent conductivity or diffusion coefficient; nonlinear electrostatics, as in the Born-Infeld theory; certain stationary potential flows in compressible fluids, in which case the forces act on sources or obstacles in the flow. The expressions for the force on a point charge is derived exactly for the limits of very low and very high charge. The force on an arbitrary body in an external field of asymptotically constant gradient, E, is shown to be F=QE, where Q is the total effective charge of the body. The corollary Q=0 implies F=0 is a generalization of d'Aembert's paradox. I show that for G>0 (as in Newtonian gravity) two point charges of the same (opposite) sign still attract (repel) each other. The opposite is true for G<0. I discuss the generalization of this to extended bodies, and derive virial relations.

Mordehai Milgrom

2001-12-19

206

Forced Spring Systems  

NSDL National Science Digital Library

Created by Lang Moore and David Smith for the Connected Curriculum Project, the purpose of this module is to explore the effects of an external driving force on a simple linear oscillator, damped or undamped. This is one within a much larger set of learning modules hosted by Duke University.

Moore, Lang

207

The fifth force  

SciTech Connect

We present a phenomenological description of the ''fifth force'' which focuses on the implications of the existing data from satellite and geophysical measurements of gravity, the Eoetvoes experiment, decays into hyperphotons, and the energy-dependence of the K/sup 0/ - anti K/sup 0/ parameters.

Fischbach, E.; Sudarsky, D.; Szafer, A.; Talmadge, C.; Aronson, S.H.

1986-01-01

208

Orbital Forces: Teacher Page  

NSDL National Science Digital Library

This activity demonstates orbital motions and forces using a tennis ball swung by a ribbon (this activity should be done outside). The Teacher Page contains background information, tennis ball preparation instructions, and wrap up information. This activity is part of Exploring Planets in the Classroom's Planetary Properties series.

209

Orbital Forces: Student Page  

NSDL National Science Digital Library

This activity teaches students about orbital motions and forces using a tennis ball swung by a ribbon. Students answer the question "What happens when you let the ball go?" Background information, activity procedures, and key words are provided. This activity is part of Exploring Planets in the Classroom's Planetary Properties series.

210

Plasmonic Marangoni forces  

NASA Astrophysics Data System (ADS)

Localized surface-tension-driven forces (microscale Marangoni effect) caused by a temperature inhomogeneity from the decay of optically excited surface plasmons into phonons have been engaged to the actuation of adsorbed and applied liquid on a thin metal film. Microfluidic operations of transport, separation, mixing and sorting have been experimentally and theoretically demonstrated using this all-optical modulation scheme.

Lereu, A.; Passian, A.; Farahi, R. H.; Zahrai, S.; Thundat, T.

2006-12-01

211

Wearing Forces Spectacles  

ERIC Educational Resources Information Center

When providing training to teachers struggling with the concept of forces, the author encourages them to start with something within the experience of the children they are teaching. For example, show them photographs taken on windy days, such as that of a tree, and ask them to explain what is happening. This encourages the children to focus on

Perrin, Graham

2012-01-01

212

Direct Aerosol Forcing Uncertainty  

DOE Data Explorer

Understanding sources of uncertainty in aerosol direct radiative forcing (DRF), the difference in a given radiative flux component with and without aerosol, is essential to quantifying changes in Earth's radiation budget. We examine the uncertainty in DRF due to measurement uncertainty in the quantities on which it depends: aerosol optical depth, single scattering albedo, asymmetry parameter, solar geometry, and surface albedo. Direct radiative forcing at the top of the atmosphere and at the surface as well as sensitivities, the changes in DRF in response to unit changes in individual aerosol or surface properties, are calculated at three locations representing distinct aerosol types and radiative environments. The uncertainty in DRF associated with a given property is computed as the product of the sensitivity and typical measurement uncertainty in the respective aerosol or surface property. Sensitivity and uncertainty values permit estimation of total uncertainty in calculated DRF and identification of properties that most limit accuracy in estimating forcing. Total uncertainties in modeled local diurnally averaged forcing range from 0.2 to 1.3 W m-2 (42 to 20%) depending on location (from tropical to polar sites), solar zenith angle, surface reflectance, aerosol type, and aerosol optical depth. The largest contributor to total uncertainty in DRF is usually single scattering albedo; however decreasing measurement uncertainties for any property would increase accuracy in DRF. Comparison of two radiative transfer models suggests the contribution of modeling error is small compared to the total uncertainty although comparable to uncertainty arising from some individual properties.

Mccomiskey, Allison

213

Perpendicular-Force Latch  

NASA Technical Reports Server (NTRS)

Latching mechanism simultaneously applies force in two perpendicular directions to install or remove electronic-equipment modules. Used to simplify installation and removal of modular equipment where movement restricted by protective clothing as in hazardous environments or where installation and removal to be performed by robots or remote manipulators. Concept adaptable to hydraulic, pneumatic, and mechanical systems.

Mattei, John P.; Buck, Peter A.; Williams, Michael D.

1990-01-01

214

Direct Aerosol Forcing Uncertainty  

SciTech Connect

Understanding sources of uncertainty in aerosol direct radiative forcing (DRF), the difference in a given radiative flux component with and without aerosol, is essential to quantifying changes in Earth's radiation budget. We examine the uncertainty in DRF due to measurement uncertainty in the quantities on which it depends: aerosol optical depth, single scattering albedo, asymmetry parameter, solar geometry, and surface albedo. Direct radiative forcing at the top of the atmosphere and at the surface as well as sensitivities, the changes in DRF in response to unit changes in individual aerosol or surface properties, are calculated at three locations representing distinct aerosol types and radiative environments. The uncertainty in DRF associated with a given property is computed as the product of the sensitivity and typical measurement uncertainty in the respective aerosol or surface property. Sensitivity and uncertainty values permit estimation of total uncertainty in calculated DRF and identification of properties that most limit accuracy in estimating forcing. Total uncertainties in modeled local diurnally averaged forcing range from 0.2 to 1.3 W m-2 (42 to 20%) depending on location (from tropical to polar sites), solar zenith angle, surface reflectance, aerosol type, and aerosol optical depth. The largest contributor to total uncertainty in DRF is usually single scattering albedo; however decreasing measurement uncertainties for any property would increase accuracy in DRF. Comparison of two radiative transfer models suggests the contribution of modeling error is small compared to the total uncertainty although comparable to uncertainty arising from some individual properties.

Mccomiskey, Allison

2008-01-15

215

``Force,'' ontology, and language  

NASA Astrophysics Data System (ADS)

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

Brookes, David T.; Etkina, Eugenia

2009-06-01

216

Measuring Your Force  

ERIC Educational Resources Information Center

This article talks about the force behind education leaders. With all the challenges facing public education today, it is difficult to remain focused and to remember why one chartered this particular leadership course. Perhaps someone respected encouraged one to take this path long ago. Perhaps this kind of service to the nation and its future

Gee, David E.

2005-01-01

217

The Force of Ideas  

ERIC Educational Resources Information Center

"The Force of Ideas" describes a little-known aspect of both educational history and Viennese psychoanalysis during the interwar years: the movement for psychoanalytic pedagogy. The author traces her father's own story, beginning with his application to the Vienna Psychoanalytic Society for training as a psychoanalytic pedagogue, as a way to

Ascher, Carol

2005-01-01

218

Intermolecular Forces: A Jigsaw Activity  

NSDL National Science Digital Library

This jigsaw activity is designed as a cooperative learning activity used to introduce the idea of intermolecular forces. Intermolecular forces are the types of attractive forces that occur between molecules in a solid, liquid, or gas. Each force causes different physical properties of matter. Each member of the group will become an expert on one type of force and then teach the rest of the group.

Edu., Boise S.

2011-09-20

219

Investigation of Calibrating Force Transducer Using Sinusoidal Force  

SciTech Connect

Sinusoidal force calibration method was studied several years before at Physikalisch-Technische Bundesanstalt (PTB). A similar dynamic force calibration system is developed at Changcheng Institute of Metrology and Measurement (CIMM). It uses electro-dynamic shakers to generate dynamic force in the range from 1 N to 20 kN, and heterodyne laser interferometers are used for acceleration measurement. The force transducer to be calibrated is mounted on the shaker, and a mass block is screwed on the top of force transducer, the sinusoidal forces realized by accelerated load masses are traceable to acceleration and mass according to the force definition. The methods of determining Spatial-dependent acceleration on mass block and measuring the end mass of force transducer in dynamic force calibration are discussed in this paper.

Zhang Li [School of Instrumentation Science and Opto-electronics Engineering, Beihang University, Beijing (China); Key Laboratory for Metrology, Changcheng Institute of Metrology and Measurement (CIMM), Beijing 100095 (China); Wang Yu; Zhang Lizhe [Key Laboratory for Metrology, Changcheng Institute of Metrology and Measurement (CIMM), Beijing 100095 (China)

2010-05-28

220

International Perspectives.  

ERIC Educational Resources Information Center

Includes "Introduction to International Perspectives" (Allen); "Volunteerism in the Welfare State: The Case of Denmark" (Habermann); "Grassroots Organizing in Bangladesh" (Chowdhury); and "Volunteerism in Latin America" (Guerra). (SK)

Allen, Kenn; Habermann, Ulla; Chowdhury, Omar Faruque; Guerra, Iraida Manzanilla

1998-01-01

221

Finite element modeling and experimentation of bone drilling forces  

NASA Astrophysics Data System (ADS)

Bone drilling is an essential part of many orthopaedic surgery procedures, including those for internal fixation and for attaching prosthetics. Estimation and control of bone drilling forces are critical to prevent drill breakthrough, excessive heat generation, and mechanical damage to the bone. This paper presents a 3D finite element (FE) model for prediction of thrust forces experienced during bone drilling. The model incorporates the dynamic characteristics involved in the process along with the accurate geometrical considerations. The average critical thrust forces and torques obtained using FE analysis, for set of machining parameters are found to be in good agreement with the experimental results.

Lughmani, W. A.; Bouazza-Marouf, K.; Ashcroft, I.

2013-07-01

222

Microrheology of cells with magnetic force modulation atomic force microscopy.  

PubMed

We propose a magnetic force modulation method to measure the stiffness and viscosity of living cells using a modified AFM apparatus. An oscillating magnetic field makes a magnetic cantilever oscillate in contact with the sample, producing a small AC indentation. By comparing the amplitude of the free cantilever motion (A0) with the motion of the cantilever in contact with the sample (A1), we determine the sample stiffness and viscosity. To test the method, the frequency-dependent stiffness of 3T3 fibroblasts was determined as a power law k(s)(f) = ? + ?(f/f)(?) (? = 7.6 10(-4) N m(-1), ? = 1.0 10(-4) N m(-1), f = 1 Hz, ? = 0.6), where the coefficient ? = 0.6 is in good agreement with rheological data of actin solutions with concentrations similar to those in cells. The method also allows estimation of the internal friction of the cells. In particular we found an average damping coefficient of 75.1 ?N s m(-1) for indentation depths ranging between 1.0 ?m and 2.0 ?m. PMID:24651941

Reblo, L M; de Sousa, J S; Mendes Filho, J; Schpe, J; Doschke, H; Radmacher, M

2014-04-01

223

Air Force Historical Research Agency  

NSDL National Science Digital Library

This Website from the US Air Force provides a brief description of the overall holdings of the agency, which are comprised of over "70,000,000 pages devoted to the history of the service, and represent the world's largest and most valuable organized collection of documents on US military aviation." The site also supplies detailed descriptions of the personal papers of Air Force members held by the agency and gives bibliographic information on 200 historical studies conducted by the agency on topics of Air Force history. Also included here are a substantive account of Air Force involvement in the Korean War; an online text on Air Force heraldry; detailed descriptions of the Air Force's force structure from 1939 to the present, giving an accounting of the types and quantities of different crafts held by the Force; and more information about Air Force organization and unit history.

224

Force reflection with compliance control  

NASA Technical Reports Server (NTRS)

Two types of systems for force-reflecting control, which enables high force-reflection gain, are presented: position-error-based force reflection and low-pass-filtered force reflection. Both of the systems are combined with shared compliance control. In the position-error-based class, the position error between the commanded and the actual position of a compliantly controlled robot is used to provide force reflection. In the low-pass-filtered force reflection class, the low-pass-filtered output of the compliance control is used to provide force reflection. The increase in force reflection gain can be more than 10-fold as compared to a conventional high-bandwidth pure force reflection system, when high compliance values are used for the compliance control.

Kim, Won S. (inventor)

1993-01-01

225

international Organisation  

E-print Network

8e édition 2006 Bureau international des poids et mesures Organisation intergouvernementale de la ------------------------------------ Organisation intergouvernementale de la Convention du Mètre #12;4 Note sur l'utilisation du texte anglais (voir décisions importantes concernant la dotation, l'organisation et le développement du Bureau international. Le

226

INTERNATIONAL COURSEGUIDE  

E-print Network

INTERNATIONAL COURSEGUIDE THE UNIVERSITY OF CANBERRA 20102010 THE UNIVERSITY OF CANBERRA CANBERRA ACT 2601 AUSTRALIA T +61 2 6201 5342 F +61 2 6201 5445 E international@canberra.edu.au www.canberra.edu.au UNDERGRADUATE POSTGRADUATE Australian Government Higher Education (CRICOS) Provider; University of Canberra

Canberra, University of

227

International english  

SciTech Connect

This paper is a presentation to the International Professional Communication Conference on International English. Presidence is taken from the Royal Society of London in 1667 to purify and simplify the English language. Because English has become the most spoken language in the world, the case in herein made to make it plainer and more easily learned. Technical communications is stressed. (FSD).

Amador, M.

1990-01-01

228

Internalized activities  

Microsoft Academic Search

This paper argues that interactive mental processes in humans have a natural tendency to replay internally and cyclically, a typical example being the tunes that run in our head for hours. The existence of these internalized activities may be shown by both simple introspection and neurological experiments, which also reveal that they occur in all sensory modalities and involve everything

Jean-Christophe Buisson; Jean-Charles Quinton

2010-01-01

229

International reputation  

E-print Network

the University of Illinois at Urbana- Champaign's efforts to maintain and strengthen its role as a global leader International Business Education and Research* g Latin American and Caribbean Studies* g Russian, East European.S. Studies g Arms Control, Disarmament, and International Security g Women and Gender in Global Perspectives

Frank, Thomas D.

230

Exploring Sources of Variation in Studies of Knowledge Structure Coherence: Comparing Force Meanings and Force Meaning Consistency across Two Turkish Cities  

ERIC Educational Resources Information Center

Substantial variation has been observed across an international series of studies examining the consistency of students' explanations of force and the most common meanings of force apparent in those explanations. On the surface, the variations among studies might be attributed to differences at the national level, but the studies also

Clark, Douglas B.; Menekse, Muhsin; Ozdemir, Gokhan; D'Angelo, Cynthis M.; Price Schleigh, Sharon

2014-01-01

231

Force Modulator System  

SciTech Connect

Many metal parts manufacturers use large metal presses to shape sheet metal into finished products like car body parts, jet wing and fuselage surfaces, etc. These metal presses take sheet metal and - with enormous force - reshape the metal into a fully formed part in a manner of seconds. Although highly efficient, the forces involved in forming metal parts also damage the press itself, limit the metals used in part production, slow press operations and, when not properly controlled, cause the manufacture of large volumes of defective metal parts. To date, the metal-forming industry has not been able to develop a metal-holding technology that allows full control of press forces during the part forming process. This is of particular importance in the automotive lightweighting efforts under way in the US automotive manufacturing marketplace. Metalforming Controls Technology Inc. (MC2) has developed a patented press control system called the Force Modulator that has the ability to control these press forces, allowing a breakthrough in stamping process control. The technology includes a series of hydraulic cylinders that provide controlled tonnage at all points in the forming process. At the same time, the unique cylinder design allows for the generation of very high levels of clamping forces (very high tonnages) in very small spaces; a requirement for forming medium and large panels out of HSS and AHSS. Successful production application of these systems testing at multiple stamping operations - including Ford and Chrysler - has validated the capabilities and economic benefits of the system. Although this technology has been adopted in a number of stamping operations, one of the primary barriers to faster adoption and application of this technology in HSS projects is system cost. The cost issue has surfaced because the systems currently in use are built for each individual die as a custom application, thus driving higher tooling costs. This project proposed to better marry the die-specific Force Modulator technology with stamping presses in the form of a press cushion. This system would be designed to operate the binder ring for multiple parts, thus cutting the per-die cost of the technology. This study reports the results of technology field application. This project produced the following conclusions: (1) The Force Modulator system is capable of operating at very high tempos in the stamping environment; (2) The company can generate substantial, controlled holding tonnage (binder ring pressure) necessary to hold high strength steel parts for proper formation during draw operations; (3) A single system can be designed to operate with a family of parts, thus significantly reducing the per-die cost of a FM system; (4) High strength steel parts made with these systems appear to show significant quality improvements; (5) The amounts of steel required to make these parts is typically less than the amounts required with traditional blank-holding technologies; and (6) This technology will aid in the use of higher strength steels in auto and truck production, thus reducing weight and improving fuel efficiency.

Redmond Clark

2009-04-30

232

Non-gravitational Force  

NASA Astrophysics Data System (ADS)

A force which is not gravitational in origin that acts on a celestial body to alter its orbit. The term is used in connection with comets, in which the outgassing of volatile material through vents leading to the surface of the nucleus can give rise to jets. Strong jets can behave as rockets and alter comets' orbits, in much the same way as the gravitational perturbations to which they are also s...

Murdin, P.

2000-11-01

233

Uplifting Force: Buoyancy & Density  

NSDL National Science Digital Library

In this investigation, learners explore the force known as buoyancy by placing various objects into water and observing how they behave (for example, which sink more quickly, which float, how much water they displace and how air plays a role in keeping objects afloat). The introduction to the lesson tells the story of Archimedes, the Greek mathematician, who first discovered the law of buoyancy while attempting to determine the mass of a crown of gold.

2013-12-18

234

Forced Granular Orifice Flow  

E-print Network

The flow of granular material through an orifice is studied experimentally as a function of force $F$ pushing the flow. It is found that the flow rate increases linearly with $F$ -- a new, unexpected result that is in contrast to the usual view that $F$, completely screened by an arch formed around the orifice, has no way of altering the rate. Employing energy balance, we show that this behavior results mainly from dissipation in the granular material.

Zheng Peng; Hepeng Zheng; Yimin Jiang

2009-08-03

235

Exploring Forces: Static Electricity  

NSDL National Science Digital Library

In this activity, learners investigate what happens when you build up static electricity on plastic balls. Learners discover that electrostatic forces cause smaller balls to suspend in a tube, while larger balls fall to the bottom. This activity shows learners that size can affect the way a material behaves. This activity is a great way to talk about how different things behave at the nanoscale.

Network, Nanoscale I.; Sciencenter

2010-01-01

236

Shear Forms Force Chains  

NSDL National Science Digital Library

This annotated image from the American Physical Society presents the results of an experiment in which small photoelastic disks on a tray are squeezed in one direction and expanded in the perpendicular direction. The site includes images made using crossed polarizers, and the birefringence of the discs reveals the forces inside them. The site includes two images, a video, and a brief description of the experiment.

2009-01-28

237

Adding Value to Force Diagrams: Representing Relative Force Magnitudes  

NASA Astrophysics Data System (ADS)

Nearly all physics instructors recognize the instructional value of force diagrams, and this journal has published several collections of exercises to improve student skill in this area.1-4 Yet some instructors worry that too few students perceive the conceptual and problem-solving utility of force diagrams,4-6 and over recent years a rich variety of approaches has been proposed to add value to force diagrams. Suggestions include strategies for identifying candidate forces,6,7 emphasizing the distinction between "contact" and "noncontact" forces,5,8 and the use of computer-based tutorials.9,10 Instructors have suggested a variety of conventions for constructing force diagrams, including approaches to arrow placement and orientation2,11-13 and proposed notations for locating forces or marking action-reaction force pairs.8,11,14,15

Wendel, Paul

2011-05-01

238

"Force," ontology, and language  

NSDL National Science Digital Library

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

Brookes, David T.; Etkina, Eugenia

2010-06-30

239

Modified entropic force  

SciTech Connect

The theory of statistical thermodynamics tells us the equipartition law of energy does not hold in the limit of very low temperatures. It is found the Debye model is very successful in explaining the experimental results for most of the solid objects. Motivated by this fact, we modify the entropic force formula which is proposed very recently. Since the Unruh temperature is proportional to the strength of the gravitational field, so the modified entropic force formula is an extension of the Newtonian gravity to the weak field. On the contrary, general relativity extends Newtonian gravity to the strong field case. Corresponding to Debye temperature, there exists a Debye acceleration g{sub D}. It is found the Debye acceleration is g{sub D}=10{sup -15} N kg{sup -1}. This acceleration is very much smaller than the gravitational acceleration 10{sup -4} N kg{sup -1} which is felt by Neptune and the gravitational acceleration 10{sup -10} N kg{sup -1} felt by the Sun. Therefore, the modified entropic force can be very well approximated by the Newtonian gravity in the Solar System and in the Galaxy. With this Debye acceleration, we find the current cosmic speeding up can be explained without invoking any kind of dark energy.

Gao Changjun [National Astronomical Observatories, Chinese Academy of Sciences, Key Laboratory of Optical Astronomy, NAOC, CAS, Beijing, 100012 and Kavli Institute for Theoretical Physics China, CAS, Beijing 100190 (China)

2010-04-15

240

Does entropic force always imply the Newtonian force law?  

E-print Network

We study the entropic force by introducing a bound $S \\le A^{3/4}$ between entropy and area which was derived by imposing the non-gravitational collapse condition. In this case, applying a modified entropic force to this system does not lead to the Newtonian force law.

Yun Soo Myung

2011-01-19

241

Force modulation for improved conductive-mode atomic force microscopy  

Microsoft Academic Search

We present an improved conductive-mode atomic force microscopy (C-AFM) method by modulating the applied loading force on the tip. Unreliable electrical contact and tip wear are the primary challenges for electrical characterization at the nanometer scale. The experiments show that force modulation reduces tip wear by a factor of three and enhances electrical contact between tip and sample, which allows

Wabe W. Koelmans; Abu Sebastian; Michel Despont; Haris Pozidis

2010-01-01

242

Flow Visualization of Forced and Natural Convection in Internal Cavities  

SciTech Connect

The report descries innovative flow visualization techniques, fluid mechanics measurements and computational models of flows in a spent nuclear fuel canister. The flow visualization methods used a fluid that reacted with a metal plate to show how a local reaction affects the surrounding flow. A matched index of refraction facility was used to take mean flow and turbulence measurements within a generic spent nuclear fuel canister. Computational models were also made of the flow in the canister. It was determined that the flow field in the canister was very complex, and modifications may need to be made to ensure that the spent fuel elements are completely passivated.

John Crepeau; Hugh M. Mcllroy,Jr.; Donald M. McEligot; Keith G. Condie; Glenn McCreery; Randy Clarsean; Robert S. Brodkey; Yann G. Guezennec

2002-01-31

243

FLOW VISUALIZATION OF FORCED AND NATURAL CONVECTION IN INTERNAL CAVITIES  

EPA Science Inventory

This research project will focus efforts on developing techniques to model fluid flow in spent nuclear fuel canisters. One treatment technique is to inject gases which react with spent fuels into storage canisters, preventing the occurrence of pyrophoric reactions. The primary go...

244

International Mathematics Education  

E-print Network

International Mathematics Education Masters Programme www.uni-bremen.de/international-mathematics-education Professional Development for Mathematics Teachers in International Schools International school mathematics in International Mathematics Education. The programme combines foci in mathematics, education and international

Hoffmeister, Thomas S.

245

BIOCHEMISTRY: Force Signaling in Biology  

NSDL National Science Digital Library

Knowledge of the effect of forces on processes in the body, such as muscle contraction, cell locomotion and division, or transport processes, has been limited. This perspective discusses new research into the effect of forces on protein conformation and function.

J. Christof (Technische Universit¤t M¼nchen;Physik Department); M. Gebhardt (Technische Universit¤t M¼nchen;Physik Department); Matthias Rief (Technische Universit¤t M¼nchen/Munich Center for Integrated Protein Science CIPSM;)

2009-06-05

246

Demonstrating and Calculating Electrostatic Forces  

NSDL National Science Digital Library

This lesson plan from the Beacon Learning Center educates students on the topic of demonstrating and calculating electrostatic forces. The lesson focuses on how electrostatic forces exist between charged objects. Florida state educational standards which the experiment exemplifies are included.

Rosen, Robert

2011-07-15

247

Radiative forcings and global warming potentials of 39 greenhouse gases  

Microsoft Academic Search

The radiative forcings and global warming potentials for 39 greenhouse gases are evaluated using narrowband and broadband radiative transfer models. Unlike many previous studies, latitudinal and seasonal variations are considered explicitly, using distributions of major greenhouse gases from a combination of chemical-transport model results and Upper Atmosphere Research Satellite (UARS) measurements and cloud statistics from the International Satellite Cloud Climatology

Atul K. Jain; Bruce P. Briegleb; K. Minschwaner; Donald J. Wuebbles

2000-01-01

248

Silk Fiber Mechanics from Multiscale Force Distribution Analysis Murat Cetinkaya,  

E-print Network

Silk Fiber Mechanics from Multiscale Force Distribution Analysis Murat Cetinkaya, Senbo Xiao, Bernd the molecular determinants for the extreme toughness of spider silk fibers. Our bottom-up computational approach of the internal strain distribution and load-carrying motifs in silk fibers on scales of both molecular

Gräter, Frauke

249

The Effects of Forced Sexual Intercourse on White Female Adolescents.  

ERIC Educational Resources Information Center

Psychological and sexual variables were compared for white women, ages 18 through 22, who did (n=41) or did not (n=400) report prior forced sexual intercourse (FSI). Those who had FSI had lower internal locus of control and higher depression scores and needed and received more psychological help than those not reporting FSI. (Author/SW)

Miller, Brent C.; And Others

1995-01-01

250

Analysis of Wind Forces on RoofTop Solar Panel  

Microsoft Academic Search

Structural loads on solar panels include forces due to high wind, gravity, thermal expansion, and earthquakes. International Building Code (IBC) and the American Society of Civil Engineers are two commonly used approaches in solar industries to address wind loads. Minimum Design Loads for Buildings and Other Structures (ASCE 7-02) can be used to calculate wind uplift loads on roof-mounted solar

Yogendra Panta; Ganesh Kudav

2011-01-01

251

Dynamic investigations of force transducers  

NASA Astrophysics Data System (ADS)

The dynamic calibration of force transducers based on the determination of inertia forces is described. The frequency dependency of the dynamic sensitivity for different types of transducers is investigated and discussed with a theoretical model. It was found that force transducers of high static quality can exhibit a completely different dynamic behavior. These differences are essentially due to influences from spring effects in the force introduction. The resonance behavior is analyzed to determine the stiffness and damping of the transducer.

Kumme, R.

252

Force threshold for hearing by direct bone conduction.  

PubMed

The bone-anchored hearing aid is connected, by means of a skin-penetrating bayonet coupling, to an implanted titanium fixture. Hence, direct bone conduction (dbc) excitation is used. Since no international standard of audiometric zero for dbc force threshold exists, it is of general interest to determine the dbc force threshold for normal hearing subjects. Two different methods have previously been applied to estimate the relation between bone conduction (bc) and dbc thresholds. One preliminary problem was to make a measurement of the output-force level of dbc transducers, which is equivalent to the situation in situ. A skull simulator, TU-1000, has been designed for measuring the output-force level of dbc transducers. The skull simulator does, in an adequate way, reflect the mechanical point impedance of the human skull. This opportunity to determine equivalent dbc force thresholds has motivated the present study in which a linear relation between the dbc force threshold and the bc force threshold was estimated. The estimate found in the present study conforms fairly well with the two previously found estimates. It is suggested that the estimate found in the present study be used as the reference equivalent threshold force level for dbc. PMID:7876434

Carlsson, P; Hkansson, B; Ringdahl, A

1995-02-01

253

Force control for mechanoinduction of impedance variation in cellular organisms  

NASA Astrophysics Data System (ADS)

Constantly exposed to various forms of mechanical forces inherent in their physical environment (such as gravity, stress induced by fluid flow or cell-cell interactions, etc), cellular organisms sense such forces and convert them into biochemical signals through the processes of mechanosensing and mechanotransduction that eventually lead to biological changes. The effect of external forces on the internal structures and activities in a cellular organism may manifest in changes its physical properties, such as impedance. Studying variation in the impedance of a cellular organism induced by the application of an external mechanical force represents a meaningful endeavor (from a biosystems perspective) in exploring the complex mechanosensing and mechanotransduction mechanisms that govern the behavior of a cellular organism under the influence of external mechanical stimuli. In this paper we describe the development of an explicit force-feedback control system for exerting an indentation force on a cellular organism while simultaneously measuring its impedance. To demonstrate the effectiveness of this force-control system, we have conducted experiments using zebrafish embryos as a test model of a cellular organism. We report experimental results demonstrating that the application of a properly controlled external force leads to a significant change in the impedance of a zebrafish embryo. These results offer support for a plausible explanation that activities of pore canals in the chorion are responsible for the observed change in impedance.

Hoo Nam, Joo; Chen, Peter C. Y.; Lu, Zhe; Luo, Hong; Ge, Ruowen; Lin, Wei

2010-02-01

254

Constructing Force-Closure Grasps  

Microsoft Academic Search

This paper presents fast and simple algorithms for directly constructing force-closure grasps based on the shape of the grasped object. The synthesis of force-closure grasps finds in dependent regions of contact for the fingertips, such that the motion of the grasped object is totally constrained. A force- closure grasp implies equilibrium grasps exist. In the reverse direction, we show that

Van-duc Nguyen

1988-01-01

255

Force Diagrams: How? and Why?  

ERIC Educational Resources Information Center

Suggests that physics students always have three questions when using force diagrams: (1) Why do I need one? (2) How do I draw one? and (3) How do I find the forces acting on a body? Provides a method to help students find answers to all three questions and understand force diagrams. (MVL)

Newburgh, Ronald

1994-01-01

256

Single electron tunneling force microscopy  

Microsoft Academic Search

The development and first application of a new scanning probe microscopy technique is described. This technique, called single-electron tunneling force microscopy (SETFM), is used to image and to perform spectroscopy of individual localized electronic states in completely nonconducting oxide surfaces. The SETFM detects single-electron tunneling events between a metallized atomic force microscope probe and individual electronic states by electrostatic force

Ezra Barrus Bussmann

2006-01-01

257

Electronic Force Gage for Welders  

NASA Technical Reports Server (NTRS)

Welding force monitored in process. Electronic force gage uses strain gage on deformable member. Oscilloscope trace of welding force photographed and compared with standard trace during calibration and troubleshooting of resistance welding equipment. Adaptable to small scale resistance welding in electronics industry.

Bradley, J. W.; Gates, G.

1983-01-01

258

International Migration  

NSDL National Science Digital Library

This Website, Push and Pull Factors of International Migration, features background and preliminary research data from a joint project of Eurostat and The Netherlands Interdisciplinary Demographic Institute the goal of which is to "improve understanding of the direct and indirect causes and mechanisms of international migration to the European Union from an internationally comparative perspective. The project is an effort to respond to the fact that "international migration flows have increased in magnitude and complexity over the past decades." Separate sections of the site provide information on the aim, objectives, and approach of the project; the research design; as well as a summary of first results on recent migration, migration motives, migration networks, and migration intentions; and further bibliographic and Web-based resources. The project is under the auspices of the Commission of the European Communities.

259

Transparency International  

NSDL National Science Digital Library

Transparency International (TI) is a non-governmental organization concerned with "increasing governmental accountability and curbing both international and national corruption." Best known for its Corruption Perceptions Index (see the February 26, 1998 Scout Report for Business and Economics), Transparency International also offers a host of other corruption-related resources, including the TI Bribers's Pay Survey and TI Bribers's Pay Index, two resources on bribe-paying in international trade; an anti-corruption directory which serves as a reference guide to efforts in central and eastern European countries to support anti-corruption programs; working papers; and other publications. Also worthy of note is TI's ten-point program directed at pressuring the World Bank Organization to help strengthen its anti-corruption programs. The layout of the TI Website is somewhat confusing, but most of the organization's research efforts can be found in the Info Centre.

260

Gradient and scattering forces in photoinduced force microscopy  

NASA Astrophysics Data System (ADS)

A theoretical and experimental analysis of the dominant forces measured in photoinduced force microscopy is presented. It is shown that when operated in the noncontact and soft-contact modes, the microscope is sensitive to the optically induced gradient force (Fg) and the scattering force (Fsc). The reconstructed force-distance curve reveals a tip-dependent scattering force in the 30-60 pN range. Whereas the scattering force is virtually insensitive to the nanoscopic tip-sample distance, the gradient force shows a z-4 dependence and is manifest only for tip-sample distances of a few nm. Measurements on glass, gold nanowires, and molecular clusters of silicon naphtalocyanine confirm that the gradient force is strongly dependent on the polarizability of the sample, enabling spectroscopic imaging through force detection. The nearly constant Fsc and the spatially dependent Fg give rise to a complex force-distance curve, which varies from point to point in the specimen and dictates the image contrast observed for a given set point of the cantilevered tip.

Jahng, Junghoon; Brocious, Jordan; Fishman, Dmitry A.; Huang, Fei; Li, Xiaowei; Tamma, Venkata Ananth; Wickramasinghe, H. Kumar; Potma, Eric Olaf

2014-10-01

261

32 CFR 705.35 - Armed Forces participation in events in the public domain.  

Code of Federal Regulations, 2012 CFR

...agencies as the United Givers Fund, Community Chests, National Health Agencies (as a group), International Service Agencies and...three days. (8) Armed Forces participation in professional sports events and post-season bowl games will normally be...

2012-07-01

262

32 CFR 705.35 - Armed Forces participation in events in the public domain.  

Code of Federal Regulations, 2011 CFR

...agencies as the United Givers Fund, Community Chests, National Health Agencies (as a group), International Service Agencies and...three days. (8) Armed Forces participation in professional sports events and post-season bowl games will normally be...

2011-07-01

263

32 CFR 705.35 - Armed Forces participation in events in the public domain.  

Code of Federal Regulations, 2010 CFR

...agencies as the United Givers Fund, Community Chests, National Health Agencies (as a group), International Service Agencies and...three days. (8) Armed Forces participation in professional sports events and post-season bowl games will normally be...

2010-07-01

264

Atomic Force Microscope  

SciTech Connect

The Atomic Force Microscope (AFM) is a recently developed instrument that has achieved atomic resolution imaging of both conducting and non- conducting surfaces. Because the AFM is in the early stages of development, and because of the difficulty of building the instrument, it is currently in use in fewer than ten laboratories worldwide. It promises to be a valuable tool for obtaining information about engineering surfaces and aiding the .study of precision fabrication processes. This paper gives an overview of AFM technology and presents plans to build an instrument designed to look at engineering surfaces.

Day, R.D.; Russell, P.E.

1988-12-01

265

Stem Cell Task Force  

NSDL National Science Digital Library

This Web site from the National Institutes of Health (NIH) provides an overview of the activities of an NIH task force established to move the stem cell research agenda forward. The section titled Scientific Research may be of particular interest to researchers in this area. It provides links to the Web sites of stem cell-related research at a number of NIH institutes, as well as an extensive information index, a FAQs page about stem cell research, information on funding opportunities, and much more.

266

Causal entropic forces.  

PubMed

Recent advances in fields ranging from cosmology to computer science have hinted at a possible deep connection between intelligence and entropy maximization, but no formal physical relationship between them has yet been established. Here, we explicitly propose a first step toward such a relationship in the form of a causal generalization of entropic forces that we find can cause two defining behaviors of the human "cognitive niche"-tool use and social cooperation-to spontaneously emerge in simple physical systems. Our results suggest a potentially general thermodynamic model of adaptive behavior as a nonequilibrium process in open systems. PMID:23679649

Wissner-Gross, A D; Freer, C E

2013-04-19

267

Ground reaction forces during treadmill running in microgravity.  

PubMed

Astronauts perform treadmill exercise during long-duration space missions to counter the harmful effects of microgravity exposure upon bone, muscle, and cardiopulmonary health. When exercising in microgravity, astronauts wear a harness and bungee system that provides forces that maintain attachment to the treadmill. Typical applied forces are less than body weight. The decreased gravity-replacement force could result in differences in ground-reaction force at a given running speed when compared to those achieved in normal gravity, which could influence the adaptive response to the performed exercise. Seven astronauts (6 m/1 f) who completed approximately 6-month missions on the International Space Station (ISS) completed a preflight (1G) and multiple in-flight (0G) data collection sessions. Ground-reaction forces were measured during running at speeds of 8.0 kph and greater on an instrumented treadmill in the lab and on the ISS. Ground-reaction forces in 0G were less than in 1G for a given speed depending upon the gravity-replacement force, but did increase with increased speed and gravity-replacement force. Ground-reaction forces attained in 1G during slower running could be attained by increasing running speed and/or increasing gravity-replacement forces in 0G. Loading rates in 1G, however, could not be replicated in 0G. While current gravity-replacement force devices are limited in load delivery magnitude, we recommend increasing running speeds to increase the mechanical loads applied to the musculoskeletal system during 0G treadmill exercise, and to potentially increase exercise session efficiency. PMID:24835563

De Witt, John K; Ploutz-Snyder, Lori L

2014-07-18

268

32 CFR 536.103 - Statutory authority for claims cognizable under international claims agreements.  

Code of Federal Regulations, 2010 CFR

...amended, for claims arising overseas under international agreements. (b) Various international agreements, such as the North Atlantic Treaty Organization (NATO) Status of Forces Agreement (SOFA) and the Partnership for Peace (PFP)...

2010-07-01

269

Force reflecting hand controller  

NASA Technical Reports Server (NTRS)

A universal input device for interfacing a human operator with a slave machine such as a robot or the like includes a plurality of serially connected mechanical links extending from a base. A handgrip is connected to the mechanical links distal from the base such that a human operator may grasp the handgrip and control the position thereof relative to the base through the mechanical links. A plurality of rotary joints is arranged to connect the mechanical links together to provide at least three translational degrees of freedom and at least three rotational degrees of freedom of motion of the handgrip relative to the base. A cable and pulley assembly for each joint is connected to a corresponding motor for transmitting forces from the slave machine to the handgrip to provide kinesthetic feedback to the operator and for producing control signals that may be transmitted from the handgrip to the slave machine. The device gives excellent kinesthetic feedback, high-fidelity force/torque feedback, a kinematically simple structure, mechanically decoupled motion in all six degrees of freedom, and zero backlash. The device also has a much larger work envelope, greater stiffness and responsiveness, smaller stowage volume, and better overlap of the human operator's range of motion than previous designs.

Mcaffee, Douglas A. (inventor); Snow, Edward R. (inventor); Townsend, William T. (inventor)

1993-01-01

270

The Force of Friction  

NSDL National Science Digital Library

In the first of two lessons of this curricular unit, students are introduced to the concept of friction as a force that impedes motion when two surfaces are in contact. Student teams use spring scales to drag objects, such as a ceramic coffee cup, along a table top or the floor, measuring the frictional force that exists between the moving object and the surface it slides on. By modifying the bottom surface of the object, students find out what kinds of surfaces generate more or less friction. They also discover that both static and kinetic friction are involved when an object initially at rest is caused to slide across a surface. In the second lesson of the unit, students design and conduct experiments to determine the effects of weight and surface area on friction. They discover that weight affects normal friction (the friction that results from surface roughness), but for very smooth surfaces, the friction due to molecular attraction is affected by contact area.

Engineering K-Phd Program

271

Pairing forces in nuclei  

SciTech Connect

In this contribution, the author mentions some features of pairing forces that are unique to nuclei and cover some areas of major interest in nuclear structure research, that involve pairing. At the level of most nuclear structure studies, nuclei are treated as consisting of two kinds of fermions (protons and neutrons) in a valence space with rather few levels. These features give rise to unique aspects of pairing forces in nuclei: (1) n-p pairing in T = 0 as well as the usual T = 1 pairing that is characteristic of like fermions; (2) a need to correct pairing calculations for the (1/N) effects that can typically be neglected in superconducting solids. An issue of current concern is the nature of the pairing interaction: several recent studies suggest a need for a density dependent form of the pairing interaction. There is a good deal of feedback between the questions of accurate calculations of pairing interactions and the form and magnitude of the pairing interaction. Finally, the authors discuss some many-body wave functions that are a generalization of the BCS wave function form, and apply them to a calculation of energy level spacings in superdeformed rotational bands.

Chasman, R.R. [Argonne National Lab., IL (United States). Physics Div.

1996-12-31

272

Environmental Crack Driving Force  

NASA Astrophysics Data System (ADS)

The effect of environment on the crack driving force is considered, first by assuming quasistatic extension of a stationary crack and second, by use of stress corrosion cracking (SCC) crack growth rate models developed previously by this author and developed further here. A quasistatic thermodynamic energy balance approach, of the Griffith-Irwin type, is used to develop stationary crack threshold expressions, tilde{J}_c , which represent the conjoint mechanical and electrochemical conditions, below which stationary cracks are stable. Expressions for the electrochemical crack driving force (CDF) were derived using an analysis that is analogous to that used by Irwin to derive his "strain energy release rate," G, which Rice showed as being equivalent to his mechanical CDF, J. The derivations show that electrochemical CDFs both for active path dissolution (APD) and hydrogen embrittlement (HE) mechanisms of SCC are simply proportional to Tafel's electrochemical anodic and cathodic overpotentials, ? a and ? c, respectively. Phenomenological SCC models based on the kinetics of APD and HE crack growth are used to derive expressions for the kinetic threshold, J scc, below which crack growth cannot be sustained. These models show how independent mechanical and environmental CDFs may act together to drive SCC crack advance. Development of a user-friendly computational tool for calculating Tafel's overpotentials is advocated.

Hall, M. M.

2013-03-01

273

Experimental Observations and Discrete Element Simulations of Bed Force Anomalies due to Force Chains in Dense Granular flows  

NASA Astrophysics Data System (ADS)

Surficial flows on volcanic edifices are often comprised of high concentrations of granular materials either derived from juvenile eruptive material or material sourced from an unstable edifice. Although much attention has been given to granular flow mobility, the physics that govern their internal behavior are still poorly understood. Our work builds on previous research showing that force chains transmit extreme localized forces to the substrates of free surface granular flows, and combines experimental and computational approaches to further investigate the forces at the bed of a simplified granular flow. A photoelastic experimental approach is used to resolve discrete forces in the granular flows, while discrete element model (DEM) simulations reproduce the experimental flows. Input parameters for the DEM are derived from measurable physical material properties, and DEM simulations using properties of natural materials corroborate experimental results. The DEM results show particular sensitivity to values prescribed for contact stiffness, which is in contrast with previous reports indicating that stiffness values have insignificant influence on flow behavior. The forces at the bed generated by force chain structures can transiently greatly exceed (by several 100%) the bed forces predicted from continuum approaches, and natural materials are more prone to excessive bed forces than photoelastic materials due to their larger contact stiffnesses. By varying the ratios of a bidisperse grain size population, continuing experiments investigate how further complexity in the granular flow regime influences force transmission via force chains. This work suggests that force chain activity may play an important role in the bed physics of dense volcanic flows by influencing substrate entrainment.

Estep, J.; Dufek, J.

2012-12-01

274

Bidirectional quantitative force gradient microscopy  

NASA Astrophysics Data System (ADS)

Dynamic operation modes of scanning force microscopy based on probe resonance frequency detection are very successful methods to study force-related properties of surfaces with high spatial resolution. There are well-recognized approaches to measure vertical force components as well as setups sensitive to lateral force components. Here, we report on a concept of bidirectional force gradient microscopy that enables a direct, fast, and quantitative real space mapping of force component derivatives in both the perpendicular and a lateral direction. It relies solely on multiple-mode flexural cantilever oscillations related to vertical probe excitation and vertical deflection sensing. Exploring this concept we present a cantilever-based sensor setup and corresponding quantitative measurements employing magnetostatic interactions with emphasis on the calculation of mode-dependent spring constants that are the foundation of quantitative force gradient studies.

Reiche, Christopher F.; Vock, Silvia; Neu, Volker; Schultz, Ludwig; Bchner, Bernd; Mhl, Thomas

2015-01-01

275

MU INTERNATIONAL DIRECTORY International Directory  

E-print Network

of Ag., Food & Natural Resources International Programs http://students.missouri.edu/~sangam/ Taiwanese Students Association http://students.missouri.edu/~tsa/ Thai Student Association http://www.missouri.edu/~thaiwww/Thai

Taylor, Jerry

276

Integrated force method versus displacement method for finite element analysis  

NASA Technical Reports Server (NTRS)

A novel formulation termed the integrated force method (IFM) has been developed in recent years for analyzing structures. In this method all the internal forces are taken as independent variables, and the system equilibrium equations (EE's) are integrated with the global compatibility conditions (CC's) to form the governing set of equations. In IFM the CC's are obtained from the strain formulation of St. Venant, and no choices of redundant load systems have to be made, in constrast to the standard force method (SFM). This property of IFM allows the generation of the governing equation to be automated straightforwardly, as it is in the popular stiffness method (SM). In this report IFM and SM are compared relative to the structure of their respective equations, their conditioning, required solution methods, overall computational requirements, and convergence properties as these factors influence the accuracy of the results. Overall, this new version of the force method produces more accurate results than the stiffness method for comparable computational cost.

Patnaik, Surya N.; Berke, Laszlo; Gallagher, Richard H.

1990-01-01

277

PERSONAL EXPOSURE TO JP-8 JET FUEL VAPORS AND EXHAUST AT AIR FORCE BASES  

EPA Science Inventory

JP-8 jet fuel (similar to commercial/international jet A-1 fuel) is the standard military fuel for all types of vehicles, including the U.S. Air Force aircraft inventory. As such, JP-8 presents the most common chemical exposure in the Air Force, particularly for flight and gro...

278

XV. The forces on an electron, according to Dirac's wave equation  

Microsoft Academic Search

It is proved that the forces on an electron, according to Dirac's wave equation, consist of a purely internal system of stresses together with those forces which would be exerted upon it by the external electromagnetic field according to classical principles.

A. Lees

1942-01-01

279

Language Study for the 1980s: Reports of the MLA-ACLS Language Task Forces.  

ERIC Educational Resources Information Center

This volume contains the reports of the task forces assigned to advise the President's Commission on Foreign Language and International Studies. Task forces were formed in the following areas: Institutional Language Policy, Commonly Taught Languages, Less Commonly Taught Languages, Public Awareness, and Government Relations. The longest report,

Brod, Richard I., Ed.

280

Force steps during viral DNA packaging ?  

E-print Network

Biophysicists and structural biologists increasingly acknowledge the role played by the mechanical properties of macromolecules as a critical element in many biological processes. This change has been brought about, in part, by the advent of single molecule biophysics techniques that have made it possible to exert piconewton forces on key macromolecules and observe their deformations at nanometer length scales, as well as to observe the mechanical action of macromolecules such as molecular motors. This has opened up immense possibilities for a new generation of mechanical investigations that will respond to such measurements in an attempt to develop a coherent theory for the mechanical behavior of macromolecules under conditions where thermal and chemical effects are on an equal footing with deterministic forces. This paper presents an application of the principles of mechanics to the problem of DNA packaging, one of the key events in the life cycle of bacterial viruses with special reference to the nature of the internal forces that are built up during the DNA packaging process.

Prashant K. Purohit; Jane' Kondev; Rob Phillips

2003-09-22

281

Observations of Internal Tides on the Oregon Continental Slope KIM I. MARTINI, MATTHEW H. ALFORD, AND ERIC KUNZE  

E-print Network

Observations of Internal Tides on the Oregon Continental Slope KIM I. MARTINI, MATTHEW H. ALFORD A complex superposition of locally forced and shoaling remotely generated semidiurnal internal tides occurs neap tides, during which the proportions of the locally and remotely forced internal tides vary

282

Forces of Nature  

NSDL National Science Digital Library

These interactive simulations allow students to investigate four of nature's more violent phenomena: volcanoes, earthquakes, hurricanes, and tornadoes. Each simulation begins with a brief written tutorial describing the characteristics and destructive potential of these hazards. Users may then adjust the various factors affecting the occurrence of these phenomena (for instance, ocean temperature, humidity, and atmospheric pressure for hurricanes) and observe the results. These simulations are related to the film National Geographic film "Forces of Nature"; other links provide access to lesson plans designed to accompany the film and to a list of locations where the film can be seen. There are also links to a preview of the film, fast facts, stories about famous natural disasters, and a glossary.

283

Deep atomic force microscopy  

NASA Astrophysics Data System (ADS)

The Atomic Force Microscope (AFM) possesses several desirable imaging features including the ability to produce height profiles as well as two-dimensional images, in fluid or air, at high resolution. AFM has been used to study a vast selection of samples on the scale of angstroms to micrometers. However, current AFMs cannot access samples with vertical topography of the order of 100 ?m or greater. Research efforts have produced AFM scanners capable of vertical motion greater than 100 ?m, but commercially available probe tip lengths are still typically less than 10 ?m high. Even the longest probe tips are below 100 ?m and even at this range are problematic. In this paper, we present a method to hand-fabricate "Deep AFM" probes with tips of the order of 100 ?m and longer so that AFM can be used to image samples with large scale vertical topography, such as fractured bone samples.

Barnard, H.; Drake, B.; Randall, C.; Hansma, P. K.

2013-12-01

284

Deep atomic force microscopy  

PubMed Central

The Atomic Force Microscope (AFM) possesses several desirable imaging features including the ability to produce height profiles as well as two-dimensional images, in fluid or air, at high resolution. AFM has been used to study a vast selection of samples on the scale of angstroms to micrometers. However, current AFMs cannot access samples with vertical topography of the order of 100 ?m or greater. Research efforts have produced AFM scanners capable of vertical motion greater than 100 ?m, but commercially available probe tip lengths are still typically less than 10 ?m high. Even the longest probe tips are below 100 ?m and even at this range are problematic. In this paper, we present a method to hand-fabricate Deep AFM probes with tips of the order of 100 ?m and longer so that AFM can be used to image samples with large scale vertical topography, such as fractured bone samples. PMID:24387435

Barnard, H.; Drake, B.; Randall, C.; Hansma, P. K.

2013-01-01

285

Deep atomic force microscopy  

SciTech Connect

The Atomic Force Microscope (AFM) possesses several desirable imaging features including the ability to produce height profiles as well as two-dimensional images, in fluid or air, at high resolution. AFM has been used to study a vast selection of samples on the scale of angstroms to micrometers. However, current AFMs cannot access samples with vertical topography of the order of 100 ?m or greater. Research efforts have produced AFM scanners capable of vertical motion greater than 100 ?m, but commercially available probe tip lengths are still typically less than 10 ?m high. Even the longest probe tips are below 100 ?m and even at this range are problematic. In this paper, we present a method to hand-fabricate Deep AFM probes with tips of the order of 100 ?m and longer so that AFM can be used to image samples with large scale vertical topography, such as fractured bone samples.

Barnard, H.; Drake, B.; Randall, C.; Hansma, P. K. [Department of Physics, University of California, Santa Barbara, California 93106 (United States)] [Department of Physics, University of California, Santa Barbara, California 93106 (United States)

2013-12-15

286

Forces of Nature  

NSDL National Science Digital Library

These interactive simulations allow students to investigate four of nature's more violent phenomena: volcanoes, earthquakes, hurricanes, and tornadoes. Each simulation begins with a brief written tutorial describing the characteristics and destructive potential of these hazards. Users may then adjust the various factors affecting the occurence of these phenomena (for instance, ocean temperature, humidity, and atmospheric pressure for hurricanes) and observe the results. These simulations are related to the film National Geogrpahic film Forces of Nature ; other links provide access to lesson plans designed to accompany the film and to a list of locations where the film can be seen. There are also links to a preview of the film, fast facts, stories about famous natural disasters, and a glossary.

2007-12-12

287

Electricity: The Mysterious Force  

NSDL National Science Digital Library

This document examines the mysterious force of electricity. The reading will focus on the physical properties of electricity and discuss topics such as (1) The Atom of Carbon, (2) Static electricity, (3) Magnets are special, (4) Magnetic fields can produce electricity, (5) Batteries produce electricity, (6) Electricity travels in circuits, (7) Secondary energy source, (8) Making electricity, (9) Moving electricity from power plants to homes, (10) Fuels that make electricity, (11) Fossil fuel power plants, (12) Nuclear power plants, (13) Hydropower plants, (14) What's a Watt, and (15) Cost of electricity. The document also depicts illustrations of a bar magnet, turbine generator, transporting electricity, U.S. electricity production, peak demand, and energy efficiency. This resource is structured as an informational booklet to supplement your energy activities or to generate discussion questions.

2008-01-01

288

Bacterial adhesion force quantification by fluidic force microscopy.  

PubMed

Quantification of detachment forces between bacteria and substrates facilitates the understanding of the bacterial adhesion process that affects cell physiology and survival. Here, we present a method that allows for serial, single bacterial cell force spectroscopy by combining the force control of atomic force microscopy with microfluidics. Reversible bacterial cell immobilization under physiological conditions on the pyramidal tip of a microchanneled cantilever is achieved by underpressure. Using the fluidic force microscopy technology (FluidFM), we achieve immobilization forces greater than those of state-of-the-art cell-cantilever binding as demonstrated by the detachment of Escherichia coli from polydopamine with recorded forces between 4 and 8 nN for many cells. The contact time and setpoint dependence of the adhesion forces of E. coli and Streptococcus pyogenes, as well as the sequential detachment of bacteria out of a chain, are shown, revealing distinct force patterns in the detachment curves. This study demonstrates the potential of the FluidFM technology for quantitative bacterial adhesion measurements of cell-substrate and cell-cell interactions that are relevant in biofilms and infection biology. PMID:25660231

Potthoff, Eva; Ossola, Dario; Zambelli, Tomaso; Vorholt, Julia A

2015-02-19

289

International Security  

NSDL National Science Digital Library

Maintained by the US Department of State's Office of International Information Programs (OIIP), formerly the USIA, this site is among the four US Policy topics covered in depth on the OIIP site. It contains a special Response to Terrorism section that presents relevant official policy texts, photo galleries, key documents, and in-focus topics such as Investigation, US Muslim Community, and Economic Issues. Other features of the International Security site include several other Issues in Focus (i.e., Arms Control and Non-Proliferation), Regions in Focus, Links to other organizations and agencies, as well as to the Electronic Journal of the Department of State, U.S. Foreign Policy Agenda.

290

Does an instrumented treadmill correctly measure the ground reaction forces?  

PubMed Central

Summary Since the 1990s, treadmills have been equipped with multi-axis force transducers to measure the three components of the ground reaction forces during walking and running. These measurements are correctly performed if the whole treadmill (including the motor) is mounted on the transducers. In this case, the acceleration of the treadmill centre of mass relative to the reference frame of the laboratory is nil. The external forces exerted on one side of the treadmill are thus equal in magnitude and opposite in direction to the external forces exerted on the other side. However, uncertainty exists about the accuracy of these measures: due to friction between the belt and the tread-surface, due to the motor pulling the belt, some believe that it is not possible to correctly measure the horizontal components of the forces exerted by the feet on the belt. Here, we propose a simple model of an instrumented treadmill and we demonstrate (1) that the forces exerted by the subject moving on the upper part of the treadmill are accurately transmitted to the transducers placed under it and (2) that all internal forces including friction between the parts of the treadmill are cancelling each other. PMID:24285705

Willems, Patrick A.; Gosseye, Thierry P.

2013-01-01

291

A multiaxial force-sensing implantable tibial prosthesis.  

PubMed

Accurate in vivo measurement of tibiofemoral forces is important in total knee arthroplasty. These forces determine polyethylene stresses and cold-flow, stress distribution in the implant, and stress transfer to the underlying implant bone interface. Theoretic estimates of tibiofemoral forces have varied widely depending on the mathematical models used. The six degrees of freedom of motion, complex articular surface topography, changing joint-contact position, intra- and extra-articular ligaments, number of muscles crossing the knee joint, and the presence of the patellofemoral joint contribute to the difficulty in developing reliable models of the knee. A prototype instrumented total knee replacement tibial prosthesis was designed, manufactured, and tested. This prosthesis accurately measured all six components of tibial forces (R2>0.997). The prosthesis was also instrumented with an internal microtransmitter for wireless data transmission. Remote powering of the sealed implanted electronics was achieved using magnetic coil induction. This device can be used to validate existing models of the knee that estimate these forces or to develop more accurate models. In conjunction with kinematic data, accurate tibiofemoral force data may be used to design more effective knee-testing rigs and wear simulators. Additional uses are intraoperative measurement of forces to determine soft-tissue balancing and to evaluate the effects of rehabilitation, external bracing, and athletic activities, and activities of daily living. PMID:16023656

Kirking, Bryan; Krevolin, Janet; Townsend, Christopher; Colwell, Clifford W; D'Lima, Darryl D

2006-01-01

292

Black carbon radiative forcing over the Tibetan Plateau  

NASA Astrophysics Data System (ADS)

estimate the snow albedo forcing and direct radiative forcing (DRF) of black carbon (BC) in the Tibetan Plateau using a global chemical transport model in conjunction with a stochastic snow model and a radiative transfer model. The annual mean BC snow albedo forcing is 2.9 W m-2 averaged over snow-covered plateau regions, which is a factor of 3 larger than the value over global land snowpack. BC-snow internal mixing increases the albedo forcing by 40-60% compared with external mixing, and coated BC increases the forcing by 30-50% compared with uncoated BC aggregates, whereas Koch snowflakes reduce the forcing by 20-40% relative to spherical snow grains. The annual BC DRF at the top of the atmosphere is 2.3 W m-2 with uncertainties of -70-85% in the plateau after scaling the modeled BC absorption optical depth to Aerosol Robotic Network observations. The BC forcings are attributed to emissions from different regions.

He, Cenlin; Li, Qinbin; Liou, Kuo-Nan; Takano, Yoshi; Gu, Yu; Qi, Ling; Mao, Yuhao; Leung, L. Ruby

2014-11-01

293

Characterization of interparticle forces in the packing of cohesive fine particles.  

PubMed

We numerically investigate force structures in the packing of fine cohesive particles using the discrete element method. By changing the particle size and therefore the van der Waals force, the effect of cohesion on the normal contact force and the total normal force, which is the sum of the normal contact forces and the van der Waals forces, is analyzed. It is shown that, with decreasing particle size, the normal contact forces become more uniform and have a narrower and more symmetric distribution, while the distributions of the total normal forces widen. Spatial correlation between the interparticle forces exists for the packing of coarse noncohesive particles. As the particle size decreases, this correlation becomes weaker for the contact forces but stronger for the total normal forces. A comparison between the effective weight of particles and the internal force structure suggests that there are differences between the particle-particle and particle-wall forces. The bimodal distribution of the effective weight indicates that there may exist two phases in the packings when cohesion is present, governed by the compressive and tensile stresses. PMID:18851026

Yang, R Y; Zou, R P; Yu, A B; Choi, S K

2008-09-01

294

Rapid internal contraction boosts DNA friction  

PubMed Central

Macroscopic objects are usually manipulated by force and observed with light. On the nanoscale, however, this is often done oppositely: individual macromolecules are manipulated by light and monitored with force. This procedure, which is the basis of single-molecule force spectroscopy, has led to much of our quantitative understanding of how DNA works, and is now routinely applied to explore molecular structure and interactions, DNAprotein reactions and protein folding. Here we develop the technique further by introducing a dynamic force spectroscopy set-up for a non-invasive inspection of the tension dynamics in a taut strand of DNA. The internal contraction after a sudden release of the molecule is shown to give rise to a drastically enhanced viscous friction, as revealed by the slow relaxation of an attached colloidal tracer. Our systematic theory explains the data quantitatively and provides a powerful tool for the rational design of new dynamic force spectroscopy assays. PMID:23653192

Otto, Oliver; Sturm, Sebastian; Laohakunakorn, Nadanai; Keyser, Ulrich F.; Kroy, Klaus

2013-01-01

295

Entropic forces in Brownian motion  

E-print Network

The interest in the concept of entropic forces has risen considerably since E. Verlinde proposed to interpret the force in Newton s second law and Gravity as entropic forces [1]. Brownian motion, the motion of a small particle (pollen) driven by random impulses from the surrounding molecules, may be the first example of a stochastic process in which such forces are expected to emerge. In this note it is shown that at least two types of entropic force can be identified in the case of 3D Brownian motion (or random walk). This yields simple derivations of known results of Brownian motion, Hook s law and, applying an external (non-radial) force, Curie s law and the Langevin-Debye equation.

Nico Roos

2014-09-11

296

Force Limited Vibration Testing Monograph  

NASA Technical Reports Server (NTRS)

The practice of limiting the shaker force in vibration tests was investigated at the NASA Jet Propulsion Laboratory (JPL) in 1990 after the mechanical failure of an aerospace component during a vibration test. Now force limiting is used in almost every major vibration test at JPL and in many vibration tests at NASA Goddard Space Flight Center (GSFC) and at many aerospace contractors. The basic ideas behind force limiting have been in the literature for several decades, but the piezo-electric force transducers necessary to conveniently implement force limiting have been available only in the last decade. In 1993, funding was obtained from the NASA headquarters Office of Chief Engineer to develop and document the technology needed to establish force limited vibration testing as a standard approach available to all NASA centers and aerospace contractors. This monograph is the final report on that effort and discusses the history, theory, and applications of the method in some detail.

Scharton, Terry D.

1997-01-01

297

International Educational  

E-print Network

International Journal of Educational Technology Opportunities and options for Web-enabled databases.D., Arizona State University The landscape of Web-based instruction is changing due to the convergence of the Web and database servers. Web-based database (WBD) servers enhance Web-based instruction by providing

Yu, Alex

298

International background.  

PubMed Central

This paper presents an international context to contemporary developments in the MRCGP examination. It reviews the situation in Australia, Canada, New Zealand and the USA and highlights some problems, solutions and changes in their examinations. Their experiences with reference to the oral and clinical components may have particular implications when planning for the UK examination. PMID:1670208

Wakeford, R.

1990-01-01

299

INTERNATIONAL SCHOLARSHIPS  

E-print Network

INTERNATIONAL STUDENT SCHOLARSHIPS scholarships.curtin.edu.auMake tomorrow better. Curtin Scholarships #12;WHAT IS A CURTIN SCHOLARSHIP? A SCHOLARSHIP AT CURTIN CAN OFFER YOU GREAT OPPORTUNITIES to complete university studies but face financial difficulties. Our scholarships range from one-off cash

300

INTERNATIONAL LIABILITY &  

E-print Network

the conflict between intrusive aviation security procedures and personal privacy? How have jurisdictions otherFIFTH ANNUAL MCGILL CONFERENCE ON INTERNATIONAL AVIATION LIABILITY & INSURANCE OCTOBER 25 26, 2013 Developments in Aviation Liability and Insurance · Unruly Passengers and Liability for Acts of Unlawful

Kambhampati, Patanjali

301

Entropic force and entanglement system  

SciTech Connect

We introduce the isothermal cavity, static holographic screen, and accelerating surface as holographic screen to study the entropic force in the presence of the Schwarzschild black hole. These may merge to provide a consistent holographic screen to define the entropic force on the stretched horizon near the event horizon. Considering the similarity between the stretched horizon of black hole and the entanglement system, we may define the entropic force in the entanglement system without referring to the source mass.

Myung, Yun Soo; Kim, Yong-Wan [Institute of Basic Science and School of Computer Aided Science, Inje University, Gimhae 621-749 (Korea, Republic of)

2010-05-15

302

Entropic force and entanglement system  

E-print Network

We introduce the isothermal cavity, static holographic screen, and accelerating surface as holographic screen to study the entropic force in the presence of the Schwarzschild black hole. These may merge to provide a consistent holographic screen to define the entropic force on the stretched horizon near the event horizon. Considering the similarity between the stretched horizon of black hole and the entanglement system, we may define the entropic force in the entanglement system without referring the source mass.

Yun Soo Myung; Yong-Wan Kim

2010-04-23

303

Shear Force in Radiometric Flows  

NASA Astrophysics Data System (ADS)

The impact of the radiometer vane thickness and edge geometry on the total radiometric force is examined numerically solving the ES BGK model kinetic equation. The flow of argon over a single vane and a multi-vane configurations is considered in the range of Knudsen numbers from 0.02 to 1. The shear force is found to reduce the total radiometric force for most vane configurations. It is shown that a change in the vane shape may offset the losses due to the shear force in a multi-vane geometry.

Gimelshein, Natalia E.; Gimelshein, Sergey F.; Ketsdever, Andrew D.; Selden, Nathaniel P.

2011-05-01

304

Force As A Momentum Current  

SciTech Connect

Advantages of a neo-Cartesian approach to classical mechanics are noted. If conservation of linear momentum is the fundamental principle, Newton's three laws become theorems. A minor paradox in static Newtonian mechanics is identified, and solved by reinterpreting force as a current of momentum. Contact force plays the role of a mere midwife in the exchange of momentum; however, force cannot be eliminated from physics because it provides the numerical value for momentum current. In this sense, in a neo-Cartesian formulation of mechanics the concept of force becomes strengthened rather than weakened.

Munera, Hector A. [International Center for Physics (CIF, Centro Internacional de Fisica), Apartado 4948, Bogota (Colombia)

2010-07-28

305

Thermomagnetic Force in Polyatomic Gases  

E-print Network

and when a magr etic field is applied. This thermo- magnetic force is normal to the surface of the disk and is an even function of the magnetic field. Measurements are reported of this force effect as a function of magnetic field and pressure for 02.../P), &z value than 02 for both the thermo- magnetic-force effect and the SB effect. A significant difference in the thermomagnetic- force effect and the SB effect occurs at large H/P values. For the SB effect, both the thermal con- ductivity...

Larchez, M. E.; Adair, Thomas W.

1971-01-01

306

How Predictive Is Grip Force Control in the Complete Absence of Somatosensory Feedback?  

ERIC Educational Resources Information Center

Grip force control relies on accurate internal models of the dynamics of our motor system and the external objects we manipulate. Internal models are not fixed entities, but rather are trained and updated by sensory experience. Sensory feedback signals relevant object properties and mechanical events, e.g. at the skin-object interface, to modify

Nowak, Dennis A.; Glasauer, Stefan; Hermsdorfer, Joachim

2004-01-01

307

Adding Value to Force Diagrams: Representing Relative Force Magnitudes  

ERIC Educational Resources Information Center

Nearly all physics instructors recognize the instructional value of force diagrams, and this journal has published several collections of exercises to improve student skill in this area. Yet some instructors worry that too few students perceive the conceptual and problem-solving utility of force diagrams, and over recent years a rich variety of

Wendel, Paul

2011-01-01

308

Incipient Sediment Movement by Shoaling Internal Gravity Waves  

Microsoft Academic Search

criterion for incipient movement of bottom sediment by shoaling internal waves by equating moments due to fluid force and gravity force acting on an exposed bed particle. Comparison of predicted conditions of incipient sediment movement with mean sediment sizes actually present on the continental shelf and continental slope southeast of New England indicates that shoreward propagation of relatively high frequency

D. A. Cacchione; J. B. Southard

1974-01-01

309

Air Force brush seal programs  

Microsoft Academic Search

Aggressive pursuit of increased performance in gas turbine engines is driving the thermodynamic cycle to higher pressure ratios, bypass ratios, and turbine inlet temperatures. As these parameters increase, internal air system and resultant thermodynamic cycle losses increase. This conflict of reducing internal airflows while increasing thermodynamic efficiency and performance is putting more emphasis on improvements to the internal flow system.

Connie Dowler

1993-01-01

310

Tunneling magnetic force microscopy  

NASA Technical Reports Server (NTRS)

We have developed a powerful new tool for studying the magnetic patterns on magnetic recording media. This was accomplished by modifying a conventional scanning tunneling microscope. The fine-wire probe that is used to image surface topography was replaced with a flexible magnetic probe. Images obtained with these probes reveal both the surface topography and the magnetic structure. We have made a thorough theoretical analysis of the interaction between the probe and the magnetic fields emanating from a typical recorded surface. Quantitative data about the constituent magnetic fields can then be obtained. We have employed these techniques in studies of two of the most important issues of magnetic record: data overwrite and maximizing data-density. These studies have shown: (1) overwritten data can be retrieved under certain conditions; and (2) improvements in data-density will require new magnetic materials. In the course of these studies we have developed new techniques to analyze magnetic fields of recorded media. These studies are both theoretical and experimental and combined with the use of our magnetic force scanning tunneling microscope should lead to further breakthroughs in the field of magnetic recording.

Burke, Edward R.; Gomez, Romel D.; Adly, Amr A.; Mayergoyz, Isaak D.

1993-01-01

311

Visualization of Force Fields in Protein StructurePrediction  

SciTech Connect

The force fields used in molecular computational biology are not mathematically defined in such a way that their mathematical representation would facilitate the straightforward application of volume visualization techniques. To visualize energy, it is necessary to define a spatial mapping for these fields. Equipped with such a mapping, we can generate volume renderings of the internal energy states in a molecule. We describe our force field, the spatial mapping that we used for energy, and the visualizations that we produced from this mapping. We provide images and animations that offer insight into the computational behavior of the energy optimization algorithms that we employ.

Crawford, Clark; Kreylos, Oliver; Hamann, Bernd; Crivelli, Silvia

2005-04-26

312

Calibration Designs for Non-Monolithic Wind Tunnel Force Balances  

NASA Technical Reports Server (NTRS)

This research paper investigates current experimental designs and regression models for calibrating internal wind tunnel force balances of non-monolithic design. Such calibration methods are necessary for this class of balance because it has an electrical response that is dependent upon the sign of the applied forces and moments. This dependency gives rise to discontinuities in the response surfaces that are not easily modeled using traditional response surface methodologies. An analysis of current recommended calibration models is shown to lead to correlated response model terms. Alternative modeling methods are explored which feature orthogonal or near-orthogonal terms.

Johnson, Thomas H.; Parker, Peter A.; Landman, Drew

2010-01-01

313

Globalization and the Growth of International Educational Testing and National Assessment  

ERIC Educational Resources Information Center

In this article, the authors develop an argument about the global forces that have led to the explosive growth of national educational assessment and international testing. In particular, the authors argue that the international acceptance of testing comes from key ideological forces in the world polity that are associated with the accelerating

Kamens, David H.; McNeely, Connie L.

2010-01-01

314

Exotic nuclei and nuclear forces  

NASA Astrophysics Data System (ADS)

I overview new aspects of the structure of exotic nuclei as compared to stable nuclei, focusing on several characteristic effects of nuclear forces. The shell structure of nuclei has been proposed by Mayer and Jensen, and has been considered to be kept valid basically for all nuclei, with well-known magic numbers, 2, 8, 20, 28, 50, . Nuclear forces were shown, very recently, to change this paradigm. It will be presented that the evolution of shell structure occurs in various ways as more neutrons and/or protons are added, and I will present basic points of this shell evolution in terms of the monopole interaction of nuclear forces. I will discuss three types of nuclear forces. The first one is the tensor force. The tensor force is one of the most fundamental nuclear forces, but its first-order effect on the shell structure has been clarified only recently in studies on exotic nuclei. The tensor force can change the spin-orbit splitting depending on the occupation of specific orbits. This results in changes of the shell structure in many nuclei, and consequently some of Mayer-Jensen's magic numbers are lost and new ones emerge, in certain nuclei. This mechanism can be understood in an intuitive way, meaning that the effect is general and robust. The second type of nuclear forces is central force. I will show a general but unknown property of the central force in the shell-model Hamiltonian that can describe nuclear properties in a good agreement with experiment. I will then demonstrate how it can be incorporated into a simple model of the central force, and will discuss how this force works in the shell evolution. Actually, by combining this central force with the tensor force, one can understand and foresee how the same proton-neutron interaction drives the shell evolution, for examples such as Sn/Sb isotopes, N = 20 nuclei and Ni/Cu isotopes. The distribution of single-particle strength is discussed also in comparison to (e,e?p) experiment on 48Ca. The shell evolution affects shapes of nuclei through Jahn-Teller-type mechanism, and a very interesting example with exotic Si isotopes is discussed. The third type of nuclear force is a three-body force, which originates in the ? particle excitation as proposed by Fujita and Miyazawa many years ago. This force is shown to produce a repulsive interaction between valence neutrons after averaging effects from the third nucleon in the core. The same three-body force is responsible for neutron stars. By including such effects of the three-body force, one can predict the correct drip line of oxygen isotopes, for instance. Thus, the landscape of atomic nuclei varies in going from stable to exotic nuclei due to particular nuclear forces, leading to a paradigm shift. This paper overviews some basic ideas and selected examples.

Otsuka, Takaharu

2013-01-01

315

Wetlands International  

NSDL National Science Digital Library

Established as a non-governmental organization, Wetlands International is concerned with promoting the conservation and wise use of wetlands on the global, regional, and national levels. Much of the information on the site is contained within a dozen or so sections along the left-hand side of the homepage. First-time visitors may want to read through the "About Us" area before proceeding to the "Introduction to Wetlands" area. Scholars and policy analysts will want to also look through the "Publications" area. Here they will find information sheets on peatland loss, user handbooks on various wetland regions, and related fact sheets for general use. Visitors may also want to peruse the "Biodiversity Programmes" area to learn more about the species and habitats that Wetlands International works to preserve through their advocacy work. The site is rounded out by a collection of recent news stories and press releases.

316

Minorities in the Armed Forces  

ERIC Educational Resources Information Center

Summarizes the findings of the Congressional Black Caucus and the specially formed task force; reports that high ranking officers have pledged to attack racial discrimination; and describes an association of minority officers whose purpose is to enhance the image of the armed forces within the minority community. (Author/JM)

Griggs, Anthony

1973-01-01

317

Driving Forces Behind Informal Sanctions  

Microsoft Academic Search

This paper investigates the driving forces behind informal sanctions in cooperation games and the extent to which theories of fairness and reciprocity capture these forces. We find that cooperators' punishment is almost exclusively targeted toward the defectors, but the latter also impose a considerable amount of spiteful punishment on the cooperators. However, spiteful punishment vanishes if the punishers can no

Armin Falk; Ernst Fehr; Urs Fischbacher

2005-01-01

318

Low-closing-force seal  

NASA Technical Reports Server (NTRS)

Compress soft, inert metal gasket between cone and corresponding socket to attach tubes to vessels containing gas samples. Technique effects seals with minimum of applied force and does not contaminate contents. Seal is formed when port connector is pushed firmly into its socket. Gold washer is deformed and forced to flow into imperfections in surfaces.

Bergquist, L. E.

1973-01-01

319

Radiative forcing and climate response  

Microsoft Academic Search

We examine the sensitivity of a climate model to a wide range of radiative forcings, including changes of solar irradiance, atmospheric CO2, O3, CFCs, clouds, aerosols, surface albedo, and a ``ghost'' forcing introduced at arbitrary heights, latitudes, longitudes, seasons, and times of day. We show that, in general, the climate response, specifically the global mean temperature change, is sensitive to

J. Hansen; M. Sato; R. Ruedy

1997-01-01

320

Climate Forcing by Anthropogenic Aerosols  

Microsoft Academic Search

Although long considered to be of marginal importance to global climate change, tropospheric aerosol contributes substantially to radiative forcing, and anthropogenic sulfate aerosol in particular has imposed a major perturbation to this forcing. Both the direct scattering of short-wavelength solar radiation and the modification of the shortwave reflective properties of clouds by sulfate aerosol particles increase planetary albedo, thereby exerting

R. J. Charlson; S. E. Schwartz; J. M. Hales; R. D. Cess; J. A. Coakley Jr.; J. E. Hansen; D. J. Hofmann

1992-01-01

321

LABORATORY I FORCES AND EQUILIBRIUM  

E-print Network

LABORATORY I FORCES AND EQUILIBRIUM Lab I -1 In biological systems, most objects of interest are in or almost in equilibrium, either stationary or moving with a constant velocity. This important condition of equilibrium is the result of a balance among all of the different forces interacting with the object

Minnesota, University of

322

International Currency  

Microsoft Academic Search

We develop a two-country, two-currency, search-theoretic model of monetary exchange, extending previous such models by endogenizing prices using bargaining theory. We analyze features of the environment that make it more likely that a given money circulates internationally. We show the value of a given currency rises if it circulates abroad, and falls if foreign money circulates locally. Also, we show

Randall Wright; Alberto Trejos

2001-01-01

323

Biodiversity International  

NSDL National Science Digital Library

This website is the homepage of Biodiversity International, "the world's leading organization dedicated to agricultural biodiversity research to improve people's lives." The site is packed with informative resources on agricultural biodiversity, including biodiversity news, downloadable publications, links to online databases, and much more. The publications library is quite a find, with a number of downloadable reports, newsletters, and online journals, available free of charge. Visitors to the site will also find a biodiversity image bank, information on biodiversity research, and much more.

2007-11-16

324

Atomic Force Microscope Operation  

NASA Technical Reports Server (NTRS)

[figure removed for brevity, see original site] Click on image for animation (large file)

This animation is a scientific illustration of the operation of NASA's Phoenix Mars Lander's Atomic Force Microscope, or AFM. The AFM is part of Phoenix's Microscopy, Electrochemistry, and Conductivity Analyzer, or MECA.

The AFM is used to image the smallest Martian particles using a very sharp tip at the end of one of eight beams.

The beam of the AFM is set into vibration and brought up to the surface of a micromachined silicon substrate. The substrate has etched in it a series of pits, 5 micrometers deep, designed to hold the Martian dust particles.

The microscope then maps the shape of particles in three dimensions by scanning them with the tip.

At the end of the animation is a 3D representation of the AFM image of a particle that was part of a sample informally called 'Sorceress.' The sample was delivered to the AFM on the 38th Martian day, or sol, of the mission (July 2, 2008).

The image shows four round pits, only 5 microns in depth, that were micromachined into the silicon substrate.

A Martian particle only one micrometer, or one millionth of a meter, across is held in the upper left pit.

The rounded particle shown at the highest magnification ever seen from another world is a particle of the dust that cloaks Mars. Such dust particles color the Martian sky pink, feed storms that regularly envelop the planet and produce Mars' distinctive red soil.

The AFM was developed by a Swiss-led consortium, with Imperial College London producing the silicon substrate that holds sampled particles.

The Phoenix Mission is led by the University of Arizona, Tucson, on behalf of NASA. Project management of the mission is by NASA's Jet Propulsion Laboratory, Pasadena, Calif. Spacecraft development is by Lockheed Martin Space Systems, Denver.

2008-01-01

325

Force level independent representations of predictive grip forceload force coupling: A PET activation study  

Microsoft Academic Search

The existence of forward internal models is a fundamental principle in theories of predictive motor control. There are indications that internal models are represented in the cerebellum. So far, no conclusive data exist on automated procedures involving predictive motor behavior. In particular, it is unknown whether single or multiple task-specific internal models handle the broad range of behavioral situations in

H. Boecker; A. Lee; M. Mhlau; A. Ceballos-Baumann; A. Ritzl; M. E. Spilker; C. Marquart; J. Hermsdrfer

2005-01-01

326

International Relations, Social Studies: 6448.20.  

ERIC Educational Resources Information Center

The forces affecting relations among nations as well as the effectiveness of decision making processes in international politics are examined and analyzed by 10th through 12th grade students in the elective quinmester course clustering around political studies. Goals emphasize helping students to understand state interaction and the variables

Coe, Rose Marie

327

International Learning Institutions: Organization, Visions, and Missions  

ERIC Educational Resources Information Center

This doctoral research examines the challenges, objectives, goals, strategies, and tactics facing leaders, administrators, faculty, students, and other stakeholders with an interest in international higher education. These broad topics necessarily encompass many factors including the market forces of globalization, increasing competition,

Van Hook, Steven R.

2011-01-01

328

Vote-trading in International Institutions  

Microsoft Academic Search

There is evidence that countries trade votes among each other in international institutions on a wide range of issues, including the use of force, trade issues, and elections of judges. Vote-trading has been criticized as being a form of corruption, undue influence, and coercion. Contrary to common wisdom, however, I argue in this article that the case for introducing policy

Ofer Eldar

2008-01-01

329

Smoke filter for internal combustion engines  

Microsoft Academic Search

A simple low cost smoke filter is described. It is adapted for use in an internal combustion engine exhaust system. It has a tapered body with a mass of alumina coated wire supported therein. The filter medium is under some longitudinal force created by a pervious support that has an unstressed curved configuration which is flattened against the medium. This

1980-01-01

330

Collaborative International Education: Reaching across Borders  

ERIC Educational Resources Information Center

Purpose: As international boundaries fade and financial pressures increase, universities are redefining the norm in educational models. The move from a synchronous classroom to a blended classroom or a completely asynchronous environment has forced faculty to be creative in delivery while overcoming complexities in the associated infrastructure.

Hilgers, Michael G.; Flachsbart, Barry B.; Elrod, Cassandra C.

2012-01-01

331

Force Sensing in Surgical Sutures  

PubMed Central

The tension in a suture is an important factor in the process of wound healing. If there is too much tension in the suture, the blood flow is restricted and necrosis can occur. If the tension is too low, the incision opens up and cannot heal properly. The purpose of this paper is to describe the design and evaluation of the Stitch Force (SF) sensor and the Hook-In Force (HIF) sensor. These sensors were developed to measure the force on a tensioned suture inside a closed incision and to measure the pulling force used to close the incision. The accuracy of both sensors is high enough to determine the relation between the force in the thread of a stitch and the pulling force applied on the suture by the physician. In a pilot study, a continuous suture of 7 stitches was applied on the fascia of the abdominal wall of multiple pigs to study this relationship. The results show that the max force in the thread of the second stitch drops from 3 (SD 1.2) to 1 (SD 0.3) newton after the 4th stitch was placed. During placement of the 5th, 6th and 7th stitch, the force in the 2nd stitch was not influenced anymore. This study indicates that in a continuous suture the force in the thread remains constant up to more than 3 stiches away from the pulled loose end of the suture. When a force feedback tool is developed specially for suturing in surgery on patients, the proposed sensors can be used to determine safety threshold for different types of tissue and sutures. PMID:24376812

Horeman, Tim; Meijer, Evert-jan; Harlaar, Joris J.; Lange, Johan F.; van den Dobbelsteen, John J.; Dankelman, Jenny

2013-01-01

332

The Internal Agency Approach to Managing and Developing Marketing Materials.  

ERIC Educational Resources Information Center

Argues that the internal agency model of a marketing communications department forces the department to compete with outside sources for work, while department members sharpen their skills and improve their knowledge of their company's business. Describes the process for creating such an internal agency, including initiating, implementing, and

Kruell, Christopher

1995-01-01

333

Internal wave excitation by vertically-oscillating bodies  

E-print Network

Internal wave excitation by vertically-oscillating bodies Morris R. Flynn , Kristjan Onu & Bruce R Internal gravity waves (IGW) are ubiquitous features of stably-stratified flow. Two types of IGW://www.taylor.math.ualberta.ca/bruce/ ­ p.2/38 #12;IGW in the environment Mountain Wave radiation Wind Wave breaking Drag force Atmosphere

Flynn, Morris R.

334

Gravity and Orbits: Gravitational Force  

NSDL National Science Digital Library

This Science Object is the second of three Science Objects in the Gravity and Orbits SciPack. It investigates the variables that influence gravitational forces acting on objects. Mass is a measure of the amount of matter that makes up an object (regardless of where that object is located) and weight is a measure of the gravitational force acting on an object. The strength of the gravitational force between masses is proportional to the product of the masses and inversely proportional to the square of the distance between them. Gravity will cause all objects at the same distance from Earth's surface to fall toward Earth with the same acceleration regardless of their mass. Learning Outcomes:? Identify variables that affect the strength of the gravitational force acting between any two objects.? Provide a quantitative description of the relationship between the mass of two object and the gravitational force between them.? Provide a qualitative description of the relationship between the mass of two objects and the gravitational force between them.? Provide a quantitative description of the relationship between distance and gravitational force. ? Provide a qualitative description of the inverse square relationship.? Recognize the effect of air resistance on object falling near Earth's surface, and thus be able to explain why two objects with different masses, at the same distance from Earth's surface, will have equal accelerations if air resistance is ignored.

National Science Teachers Association (NSTA)

2006-11-01

335

Electrostatic forces in planetary rings  

NASA Technical Reports Server (NTRS)

The average charge on a particle in a particle-plasma cloud, the plasma potential inside the cloud, and the Coulomb force acting on the particle are calculated. The net repulsive electrostatic force on a particle depends on the plasma density, temperature, density of particles, particle size, and the gradient of the particle density. In a uniformly dense ring the electrostatic repulsion is zero. It is also shown that the electrostatic force acts like a pressure force, that even a collisionless ring can be stable against gravitational collapse, and that a finite ring thickness does not necessarily imply a finite velocity dispersion. A simple criterion for the importance of electrostatic forces in planetary rings is derived which involves the calculation of the vertical ring thickness which would result if only electrostatic repulsion were responsible for the finite ring thickness. Electrostatic forces are entirely negligible in the main rings of Saturn and the E and G rings. They may also be negligible in the F ring. However, the Uranian rings and Jupiter's ring seem to be very much influenced by electrostatic repulsion. In fact, electrostatic forces could support a Jovian ring which is an order of magnitude more dense than observed.

Goertz, C. K.; Shan, Linhua; Havnes, O.

1988-01-01

336

The Army Special Operations Forces Role in Force Projection  

Microsoft Academic Search

ABSTRACT AUTHOR:,Jack C. Zeigler Jr. TITLE: The Army Special Operations Forces Role in Force Projection FORMAT:,Strategy Research Project DATE:,07 April 2003, PAGES: 30,CLASSIFICATION: Unclassified President George W. Bush summarized,his National Security Strategy in a speech,to West Point cadets in June 2002 when he stated, If we wait for threats to fully materialize, we will have waited too long. In the

Colonel Jack; C. Zeigler

337

Complexity International  

NSDL National Science Digital Library

Complexity International (CI) is an electronic journal devoted to "the field of complex systems, the generation of complex behaviour from the interaction of multiple parallel processes." The journal covers a wide variety of topics, including genetic algorithms, neural networks, and chaos theory. Because much of the focus is based on technological imitation of biological processes, some of the papers are closely tied to the life sciences. Volumes are added to on a continual basis as papers are accepted. Due to the lengthy acceptance process, it is especially useful that the CI Web site offers drafts of current submissions.

338

IEEE Computer Society Task Force on Cluster Computing  

NSDL National Science Digital Library

The TFCC is an international forum promoting cluster computing research and education. It participates in helping to set up and promote technical standards in this area. The Task Force is concerned with issues related to the design, analysis, development and implementation of cluster-based systems. Of particular interest are: cluster hardware technologies, distributed environments, application tools and utilities, as well as the development and optimisation of cluster-based applications.

339

Feeling molecular forces: tactile feedback to enhance drug design  

E-print Network

-2754. VITA Jocylin Amber Williams was born in 1977 and spent her childhood traversing the globe as an U. S. Air Force military brat. She received her high school diploma from M. B. Lamar High School in Houston, Texas along with an International... Baccalaureate Diploma. She is currently a senior biochemistry major at Texas ARM University and will graduate as a University Fellow with University Honors, and biochemistry honors in August 2000. Honors include recognition as a finalist for a Fulbright Grant...

Williams, Jocylin Amber

2013-02-22

340

Force field parameters for aminoorganosilanes  

NASA Astrophysics Data System (ADS)

Force field parameters for new compound classes are an important prerequisite for the fast and reliable modeling of these compounds with commercial available modeling software. The development of MMX force field parameters for aminoorganosilanes is described in this work. Combined efforts have been undertaken including synthesis, structural characterization of suitable compounds, and quantum chemical calculation with a systematic set of model compounds. 1,2-Dibenzylamino-1,2-dichloro-dimethyldisilane has been synthesized and characterized by X-ray structure analysis. It is possible to calculate bond lengths and angles of this and other aminosilanes with the new force field parameters.

Meinel, Birgit; Gnther, Betty; Bhme, Uwe

2015-01-01

341

The force of impacting rain.  

PubMed

Drop impacts are difficult to characterize due to their transient, non-stationary nature. We discuss the force generated during such impacts, a key quantity for animals, plants, roofs or soil erosion. Although a millimetric drop has a modest weight, it can generate collision forces on the order of thousand times this weight. We measure and discuss this amplification, considering natural parameters such as drop radius and density, impact speed and response time of the substrate. We finally imagine two kinds of devices allowing us to deduce the size of the raindrop from impact forces. PMID:24879634

Soto, Dan; De Larivire, Aurlie Borel; Boutillon, Xavier; Clanet, Christophe; Qur, David

2014-07-21

342

Pendulum for precision force measurement  

NASA Astrophysics Data System (ADS)

A pendulum and a method for correcting the restoring force of the pendulum are proposed for realizing an instrument based on the levitation mass method without the use of pneumatic linear bearings. As an example a material tester using the pendulum, which evaluates the mechanical response of general objects against impact forces, is developed. The characteristics of the restoring force are accurately determined using the same instrument under the free-swing condition without the object under test. To demonstrate the high performance of the developed instrument, the impact response of a gel block is accurately determined. The possible applications of the developed method are discussed.

Fujii, Yusaku

2006-03-01

343

Specificity of internal representations underlying grasping.  

PubMed

The present study examines anticipatory control of fingertip forces during grasping based on the center of mass (CM) of a manipulated object. Subjects lifted an object using a precision grip while the fingertip forces and the angle about the vertical axis (roll) were measured. The object's CM could be shifted to the left or right of the object's center parallel to the grip axis without changing it's visual appearance. Subjects performed 20 lifts with the CM in the center, left, and right side of the object, respectively. Subjects were instructed to lift the object while preventing it from tilting. Within three to five lifts, subjects were able to asymmetrically partition the load force development before lift-off such that it was higher in the digit opposing the CM. This anticipatory load force partitioning prevented the object from rolling sideways at lift-off. To determine whether the internal representation underlying the anticipatory control is specific to the effectors used to form it, subjects performed five lifts with the right hand with the CM on one side. Following these lifts, they rotated the object 180 degrees around the vertical axis and performed one lift with the same hand or they translated the object to the left side of the body (with or without rotating it) and performed one lift with the left hand. Despite subjects' explicit knowledge of the new weight distribution, they were unable to appropriately scale the load forces at each digit, resulting in a subsequent large roll of the object. The findings suggest that within a few lifts subjects achieve a stable internal representation which accounts for the object's CM and is used to scale the fingertip forces in advance. They also suggest that this representation, which is used for anticipatory control of fingertip forces, is specific to the effectors used to form it. We propose that multiple internal representations may be used during the anticipatory control of grasping. PMID:11067981

Salimi, I; Hollender, I; Frazier, W; Gordon, A M

2000-11-01

344

Einstein's osmotic equilibrium of colloidal suspensions in conservative force fields  

NASA Astrophysics Data System (ADS)

Predicted by Einstein in his 1905 paper on Brownian motion, colloidal particles in suspension reach osmotic equilibrium under gravity. The idea was demonstrated by J.B. Perrin to win Nobel Prize in Physics in 1926. We show Einstein's equation for osmotic equilibrium can be applied to colloids in a conservative force field generated by optical gradient forces. We measure the osmotic equation of state of 100nm Polystyrene latex particles in the presence of KCl salt and PEG polymer. We also obtain the osmotic compressibility, which is important for determining colloidal stability and the internal chemical potential, which is useful for predicting the phase transition of colloidal systems. This generalization allows for the use of any conservative force fields for systems ranging from colloidal systems to macromolecular solutions.

Fu, Jinxin; Ou-Yang, H. Daniel

2014-09-01

345

PBS Learning Media: Teaching from Space - Centripetal Force  

NSDL National Science Digital Library

This unique five-minute video features a NASA astronaut demonstrating centripetal force in ways students cannot observe in daily life. The video was shot in a weightless environment -- on board the International Space Station. The astronaut swings a tethered tool around a cord, rotates a bag of tea to show how air bubbles are pushed to the center, and spins a water droplet to show deformation resulting from centripetal force. The video was designed to promote understanding of the force that keeps planets in their orbits and keeps humans in their seats on a looping roller coaster. The video itself was developed by the NASA Teaching from Space program, and packaged to include background information and discussion questions. PBS Learning Media is a growing collection of videos, lessons, and activities assembled by researchers, scientists, and experienced teachers to promote the use of digital resources in the classroom.

2012-11-19

346

The new science of sales force productivity.  

PubMed

For years, sales managers at many companies have relied on top performers and sheer numbers of sales reps to stay competitive. But while they may have squeaked by on this wing-and-a-prayer technique, their sales teams haven't thrived the way they once did. Today's most successful sales leaders are taking a more scientific approach. Savvy managers are reshaping their tactics in response to changing markets. They are reaching out to new customers in innovative ways. And they are increasing productivity by helping the reps they already have make the most of their skills and resources. Leaders who take a scientific approach to sales force effectiveness have learned to use four levers to boost their reps' productivity in a predictable and manageable way. First, they systematically target their firms' offerings, matching the right products with the right customers. Second, they optimize the automation, tools, and procedures at their disposal, providing reps with the support they need to boost sales.Third, they analyze and manage their reps' performance, measuring both internal processes and results to determine where their teams' strengths and weaknesses are. Fourth, they pay close attention to sales force deployment--how well sales, support, marketing, and delivery resources are matched to customers. These four levers can help sales leaders increase productivity across the board, the authors say, though they have the greatest impact on lower-ranked performers. The overall effect of increasing the average sales per employee can be exponential; it means a company won't have to rely on just a few talented individuals to stay competitive. This is especially important because finding and keeping star salespeople is more difficult than ever. What's more, managers who optimize the sales forces they already have can see returns they never thought possible. PMID:16967626

Ledingham, Dianne; Kovac, Mark; Simon, Heidi Locke

2006-09-01

347

Direct detection of intermolecular forces by atomic force microscopy  

NASA Astrophysics Data System (ADS)

The phenomenon of adhesion appears in various applications of everyday life, ranging from PostIt Notes(TM) and Scotch Tape(TM), to the assembly of aircraft and space shuttles. However, adhesion on the molecular scale is fundamentally different from the adhesion that we experience in the macroscopic world. While macroscopic objects require special adhesives or glues to bind them together, microscale and nanoscale objects and molecules commonly have a high affinity to adhere to each other. A detailed description of intermolecular forces is therefore of key importance in order to understand a wide range of phenomena, ranging from macroscopic properties of materials to molecular recognition. Two key aspects of the atomic force microscope (AFM), namely its sensitivity to sub-nanoNewton forces and its very sharp probe, offer the opportunity to measure interactions between very small numbers of molecules. Through chemical tailoring of both substrates and AFM probes with self-assembled monolayers (SAMs), measurements of forces acting between specific functional groups can be measured. Furthermore, the force required to rupture a single chemical bond can be obtained by a detailed analysis of the histograms of rupture forces. A new model was derived to examine the relationship between the various experimental variables and the shape of histograms of rupture forces when discrete chemical bonds are formed between the AFM probe and substrate. Calculations based on the model demonstrated that in measurements aimed at detecting single bond rupture forces, strict limits are put on the size of the AFM probe, the relative magnitude of the interfacial energies and the bond formation probability. These results were used in two experimental systems where the single bond rupture force was successfully measured: (i) the abstraction of a single Au-S complex from an Au coated AFM probe; and (ii) the rupture of a single charge-transfer (CT) complex between tetramethylphenylenediamine (TMPD) and tetracyanoquinodimethane (TCNQ). Measurements involving only one molecule at a time were conducted using polymer chains chemically grafted to the AFM probe and substrate. In these measurements, the effect of the solvent on the elasticity of the poly-ethylene-propylene oligomers was directly observed in the force-elongation profile.

Skulason, Hjalti

348

Modifying landing mat material properties may decrease peak contact forces but increase forefoot forces in gymnastics landings  

Microsoft Academic Search

This study investigated how changes in the material properties of a landing mat could minimise ground reaction forces (GRF) and internal loading on a gymnast during landing. A multi-layer model of a gymnastics competition landing mat and a subject-specific seven-link wobbling mass model of a gymnast were developed to address this aim. Landing mat properties (stiffness and damping) were optimised

Chris Mills; Maurice R. Yeadon; Matthew T. G. Pain

2010-01-01

349

Getting Around The Coriolis Force  

NSDL National Science Digital Library

This website presents a qualitative explanation of the Coriolis force. The website uses vectors diagrams to help explain why moving objects on Earth (like artillery shells) seem to curve. Applications to high and low pressure systems are described.

2007-07-19

350

ATOMIC FORCE Hilary Wenyi Zheng  

E-print Network

strength. Sensor devives: 1. Higher sensitivity; 2. For cells, arteries and veins. Drug delivery: 1 electric force without conduction : ·PVP sample was prepared by Steven Institute of Technology: Hoboken

Petta, Jason

351

Investigating Forces: Balloon car activity  

NSDL National Science Digital Library

This is a guided inquiry-based lab that investigates forces exerted on a group of student-designed and engineered "balloon cars". Each group of students is then challenged to build a "balloon car" that travels a maximum distance.

352

Labor Force Trends: A Bibliography  

ERIC Educational Resources Information Center

This annotated bibliography reflects relevant issues covered in the accompanying article in this issue (CE 506 866). It presents a general outline of recent literature on labor force participation, including underlying secular movements and cyclical analysis. (MF)

Devens, Richard M.

1977-01-01

353

A graphene surface force balance.  

PubMed

We report a method for transferring graphene, grown by chemical vapor deposition, which produces ultraflat graphene surfaces (root-mean-square roughness of 0.19 nm) free from polymer residues over macroscopic areas (>1 cm(2)). The critical step in preparing such surfaces involves the use of an intermediate mica template, which itself is atomically smooth. We demonstrate the compatibility of these model surfaces with the surface force balance, opening up the possibility of measuring normal and lateral forces, including friction and adhesion, between two graphene sheets either in contact or across a liquid medium. The conductivity of the graphene surfaces allows forces to be measured while controlling the surface potential. This new apparatus, the graphene surface force balance, is expected to be of importance to the future understanding of graphene in applications from lubrication to electrochemical energy storage systems. PMID:25171130

Britton, Jude; Cousens, Nico E A; Coles, Samuel W; van Engers, Christian D; Babenko, Vitaliy; Murdock, Adrian T; Kos, Antal; Perkin, Susan; Grobert, Nicole

2014-09-30

354

Teleoperation with virtual force feedback  

SciTech Connect

In this paper we describe an algorithm for generating virtual forces in a bilateral teleoperator system. The virtual forces are generated from a world model and are used to provide real-time obstacle avoidance and guidance capabilities. The algorithm requires that the slaves tool and every object in the environment be decomposed into convex polyhedral Primitives. Intrusion distance and extraction vectors are then derived at every time step by applying Gilbert`s polyhedra distance algorithm, which has been adapted for the task. This information is then used to determine the compression and location of nonlinear virtual spring-dampers whose total force is summed and applied to the manipulator/teleoperator system. Experimental results validate the whole approach, showing that it is possible to compute the algorithm and generate realistic, useful psuedo forces for a bilateral teleoperator system using standard VME bus hardware.

Anderson, R.J.

1993-08-01

355

INTERNATIONAL STUDENT SURVEY INTERNATIONAL STUDENT SURVEY  

E-print Network

INTERNATIONAL STUDENT SURVEY OCT 2010 1 SO L I D U MPE- internati- ona l s INTERNATIONAL STUDENT SURVEY SUMMARY AND RESULTS OCTOBER 2010 au AARHUS UNIVERSITET #12;Aarhus universitet International Centre;INTERNATIONAL STUDENT SURVEY OCT 2010 3 Introduction Survey Objectives

356

GEOPHYSICAL RESEARCH LETTERS, VOL. ???, XXXX, DOI:10.1029/, Rapid generation of high-frequency internal waves beneath a  

E-print Network

-frequency internal waves beneath a wind and wave forced oceanic surface mixed-layer Jeff A. Polton,1 Jerome A. Smith,1 Jennifer A. MacKinnon,1 and Andr´es E. Tejada-Mart´inez2 High-frequency internal waves generated-frequency internal waves in the stratified fluid below. The internal waves evolve such that their vector phase

MacKinnon, Jennifer

357

Resonant Generation of Internal Waves on a Model Continental Slope H. P. Zhang, B. King, and Harry L. Swinney  

E-print Network

Resonant Generation of Internal Waves on a Model Continental Slope H. P. Zhang, B. King, and Harry that of internal waves. Fluid motion with a velocity an order of magnitude larger than that of the forcing occurs interior called internal waves. In a nonrotating stratified fluid (Coriolis parameter f 0), internal waves

Texas at Austin. University of

358

A topaz international program overview  

SciTech Connect

Little did these visionaries know that the formation of the ``TOPAZ II Program,`` using former military space power technology of the Soviet Union, would become the preeminent example of technology cooperation between two former adversaries. A unique teaming arrangement formed in New Mexico, called the New Mexico Strategic Alliance and consisting of the Air Force Phillips Laboratory, Sandia National Laboratories, the University of New Mexico, and Los Alamos Nationalo Laboratory, was a key ingredient in making this program a success. A brief summary of some of the highlights of this technology partnership is given to explain how international patnerships of this type can enable commercialization and technology transfer.

Thome, F.V.; Wyant, F.J. [USAF Phillips Laboratory/VTPN, 901 University Blvd SE, Albuquerque, New Mexico 87106 (United States); Mulder, D. [Sandia National Laboratories, 901 University Blvd SE, Albuquerque, New Mexico 87106 (United States); McCarson, T.D. Jr. [New Mexico Engineering Research Institute, University of New Mexico, 901 University Blvd, SE Albuquerque, New Mexico 87106 (United States); Ponomarev-Stepnoi, N.N. [RRC Kurchatov Institute, Kurchatov SQ 1, Moscow, Russia 123182 (Russian Federation)

1995-01-20

359

49 CFR 193.2067 - Wind forces.  

...Siting Requirements 193.2067 Wind forces. (a) LNG facilities... (1) The direct effect of wind forces; (2) The pressure...storage tanks, impact forces and potential penetrations by wind borne missiles. (b)...

2014-10-01

360

Work Force Planning for Public Power Utilities  

E-print Network

Work Force Planning for Public Power Utilities: Ensuring Resources to Meet Projected ............................................ 4 The Aging Work Force Still Challenges Public Power ........................... 6 Public Power Utilities Need to Do More to Prepare for Their Future Work Force Needs

361

The influence of catch trials on the consolidation of motor memory in force field adaptation tasks  

PubMed Central

In computational neuroscience it is generally accepted that human motor memory contains neural representations of the physics of the musculoskeletal system and the objects in the environment. These representations are called internal models. Force field studies, in which subjects have to adapt to dynamic perturbations induced by a robotic manipulandum, are an established tool to analyze the characteristics of such internal models. The aim of the current study was to investigate whether catch trials during force field learning could influence the consolidation of motor memory in more complex tasks. Thereby, the force field was more than double the force field of previous studies (35 Ns/m). Moreover, the arm of the subjects was not supported. A total of 46 subjects participated in this study and performed center-out movements at a robotic manipulandum in two different force fields. Two control groups learned force field A on day 1 and were retested in the same force field on day 3 (AA). Two test groups additionally learned an interfering force field B (= ?A) on day 2 (ABA). The difference between the two test and control groups, respectively, was the absence (0%) or presence (19%) of catch trials, in which the force field was turned-off suddenly. The results showed consolidation of force field A on day 3 for both control groups. Test groups showed no consolidation of force field A (19% catch trials) and even poorer performance on day 3 (0% catch trials). In conclusion, it can be stated that catch trials seem to have a positive effect on the performance on day 3 but do not trigger a consolidation process as shown in previous studies that used a lower force field viscosity with supported arm. These findings indicate that the results of previous studies in which less complex tasks were analyzed, cannot be fully transferred to more complex tasks. Moreover, the effects of catch trials in these situations are insufficiently understood and further research is needed. PMID:23898319

Focke, Anne; Stockinger, Christian; Diepold, Christina; Taubert, Marco; Stein, Thorsten

2013-01-01

362

Integration of contractile forces during tissue invagination  

E-print Network

Contractile forces generated by the actomyosin cytoskeleton within individual cells collectively generate tissue-level force during epithelial morphogenesis. During Drosophila mesoderm invagination, pulsed actomyosin ...

Martin, Adam C.

363

Forced oscillations with continuum models of atomic force microscopy  

NASA Astrophysics Data System (ADS)

The dynamics of the AFM-atomic force microscope follows a model based in a Timoshenko cantilever beam with a tip attached at the free end and acting with the surface of a sample. General boundary conditions arise when the tip is either in contact or non-contact with the surface. The governing equations are given in matrix conservative form subject to localized loads. The eigenanalysis is done with a fundamental matrix response of a damped second-order matrix differential equation. Forced responses are found by using a Galerkin approximation of the matrix impulse response. Simulations results with harmonic and pulse forcing show the filtering character and the effects of the tip-sample interaction at the end of the beam.

Claeyssen, Julio R.; Tsukazan, Teresa; Tonetto, Leticia; Balthazar, Jose M.

2012-11-01

364

Model Engine Performance Measurement From Force Balance Instrumentation  

NASA Technical Reports Server (NTRS)

A large scale model representative of a low-noise, high bypass ratio turbofan engine was tested for acoustics and performance in the NASA Lewis 9- by 15-Foot Low-Speed Wind Tunnel. This test was part of NASA's continuing Advanced Subsonic Technology Noise Reduction Program. The low tip speed fan, nacelle, and an un-powered core passage (with core inlet guide vanes) were simulated. The fan blades and hub are mounted on a rotating thrust and torque balance. The nacelle, bypass duct stators, and core passage are attached to a six component force balance. The two balance forces, when corrected for internal pressure tares, measure the total thrust-minus-drag of the engine simulator. Corrected for scaling and other effects, it is basically the same force that the engine supports would feel, operating at similar conditions. A control volume is shown and discussed, identifying the various force components of the engine simulator thrust and definitions of net thrust. Several wind tunnel runs with nearly the same hardware installed are compared, to identify the repeatability of the measured thrust-minus-drag. Other wind tunnel runs, with hardware changes that affected fan performance, are compared to the baseline configuration, and the thrust and torque effects are shown. Finally, a thrust comparison between the force balance and nozzle gross thrust methods is shown, and both yield very similar results.

Jeracki, Robert J.

1998-01-01

365

Experimental observation of a strong mean flow induced by internal gravity waves Guilhem Bordes,1, a)  

E-print Network

Experimental observation of a strong mean flow induced by internal gravity waves Guilhem Bordes,1 mean flow induced by internal gravity waves. A wave beam is forced at the lateral boundary of a tank fluids support the existence of anisotropic dispersive waves, called internal gravity waves, which play

Paris-Sud XI, Université de

366

International Technology Exchange Division: 1993 Annual report  

SciTech Connect

The Office of Technology Development (OTD) was established to ensure that reliable and acceptable technologies are available for implementation at DOE sites and that a technically trained work force is available to complete the EM mission by 2019. OTD established the International Technology Exchange Staff (ITES) to identify, evaluate, and acquire international technologies which can accelerate US DOE cleanup operations. ITES`s goal is to pursue international collaboration among government organizations, educational institutions, and private industry to identify world-wide needs and available technologies that will meet US environmental needs in general, and EM cleanup needs in particular; and establish mechanisms by which US government ER/WM technologies will be transferred to the US private sector for commercialization and export to international markets. ITES has developed the following strategic objectives to implement its international goals: develop and implement EM`s policy for international programs in accordance with DOE and US Government policies and regulations; establish efficient and predictable international technology transfer mechanisms; assist the US private sector in the commercialization and deployment of federally funded EM technologies and related knowledge in international markets; leverage US and non-US resources to accelerate international development and regulatory acceptance of EM technologies; contribute to the improvement of EM`s training of US students, scientists, and managers on international environmental issues. A summary and descriptions of program activities and accomplishments are given for 17 programs which comprise the four main areas of the ITES program: Activities with the Former Soviet Union, International Technology Transfer, International Cooperation, and Information Systems and Publications. Selected papers are indexed separately for inclusion in the Energy Science and Technology Database.

Not Available

1993-12-31

367

Risk assessment in international operations.  

PubMed

During international peace-keeping missions, a diverse number of non-battle hazards may be encountered, which range from heavily polluted areas, endemic disease, toxic industrial materials, local violence, traffic, and even psychological factors. Hence, elevated risk levels from a variety of sources are encountered during deployments. With the emphasis within the Swedish military moving from national defense towards prioritization of international missions in atypical environments, the risk of health consequences, including long term health effects, has received greater consideration. The Swedish military is interested in designing an optimal approach for assessment of health threats during deployments. The Medical Intelligence group at FOI CBRN Security and Defence in Ume has, on request from and in collaboration with the Swedish Armed Forces, reviewed a variety of international health threat and risk assessment models for military operations. Application of risk assessment methods used in different phases of military operations will be reviewed. An overview of different international approaches used in operational risk management (ORM) will be presented as well as a discussion of the specific needs and constraints for health risk assessment in military operations. This work highlights the specific challenges of risk assessment that are unique to the deployment setting such as the assessment of exposures to a variety of diverse hazards concurrently. PMID:18325560

Stricklin, Daniela L

2008-11-15

368

Risk assessment in international operations  

SciTech Connect

During international peace-keeping missions, a diverse number of non-battle hazards may be encountered, which range from heavily polluted areas, endemic disease, toxic industrial materials, local violence, traffic, and even psychological factors. Hence, elevated risk levels from a variety of sources are encountered during deployments. With the emphasis within the Swedish military moving from national defense towards prioritization of international missions in atypical environments, the risk of health consequences, including long term health effects, has received greater consideration. The Swedish military is interested in designing an optimal approach for assessment of health threats during deployments. The Medical Intelligence group at FOI CBRN Security and Defence in Umea has, on request from and in collaboration with the Swedish Armed Forces, reviewed a variety of international health threat and risk assessment models for military operations. Application of risk assessment methods used in different phases of military operations will be reviewed. An overview of different international approaches used in operational risk management (ORM) will be presented as well as a discussion of the specific needs and constraints for health risk assessment in military operations. This work highlights the specific challenges of risk assessment that are unique to the deployment setting such as the assessment of exposures to a variety of diverse hazards concurrently.

Stricklin, Daniela L. [FOI, Swedish Defence Research Agency, CBRN Security and Defence, Umea, SE-90182 (Sweden)], E-mail: daniela.stricklin@foi.se

2008-11-15

369

Long-term climate response to stabilized and overshoot anthropogenic forcings beyond the twenty-first century  

Microsoft Academic Search

From multi-ensembles of climate simulations using the Community Climate System Model version 3, global climate changes have\\u000a been investigated focusing on long-term responses to stabilized anthropogenic forcings. In addition to the standard forcing\\u000a scenarios for the current international assessment, an overshoot scenario, where radiative forcings are decreased from one\\u000a stabilized level to another, is also considered. The globally-averaged annual surface

Junichi Tsutsui; Yoshikatsu Yoshida; Dong-Hoon Kim; Hideyuki Kitabata; Keiichi Nishizawa; Norikazu Nakashiki; Koki Maruyama

2007-01-01

370

Sensing mode atomic force microscope  

DOEpatents

An atomic force microscope utilizes a pulse release system and improved method of operation to minimize contact forces between a probe tip affixed to a flexible cantilever and a specimen being measured. The pulse release system includes a magnetic particle affixed proximate the probe tip and an electromagnetic coil. When energized, the electromagnetic coil generates a magnetic field which applies a driving force on the magnetic particle sufficient to overcome adhesive forces exhibited between the probe tip and specimen. The atomic force microscope includes two independently displaceable piezo elements operable along a Z-axis. A controller drives the first Z-axis piezo element to provide a controlled approach between the probe tip and specimen up to a point of contact between the probe tip and specimen. The controller then drives the first Z-axis piezo element to withdraw the cantilever from the specimen. The controller also activates the pulse release system which drives the probe tip away from the specimen during withdrawal. Following withdrawal, the controller adjusts the height of the second Z-axis piezo element to maintain a substantially constant approach distance between successive samples.

Hough, Paul V. C. (Port Jefferson, NY); Wang, Chengpu (Upton, NY)

2003-01-01

371

Note: Helical nanobelt force sensors  

SciTech Connect

We present the fabrication and characterization of helical nanobelt force sensors. These self-sensing force sensors are based on the giant piezoresistivity of helical nanobelts. The three-dimensional helical nanobelts are self-formed from 27 nm-thick n-type InGaAs/GaAs bilayers using rolled-up techniques, and assembled onto electrodes on a micropipette using nanorobotic manipulations. The helical nanobelt force sensors can be calibrated using a calibrated atomic force microscope cantilever system under scanning electron microscope. Thanks to their giant piezoresistance coefficient (515 Multiplication-Sign 10{sup -10} Pa{sup -1}), low stiffness (0.03125 N/m), large-displacement capability ({approx}10 {mu}m), and good fatigue resistance, they are well suited to function as stand-alone, compact ({approx}20 {mu}m without the plug-in support), light ({approx}5 g including the plug-in support), versatile and large range ({approx}{mu}N) and high resolution ({approx}nN) force sensors.

Hwang, G. [Laboratory for Photonics and Nanostructures, Centre National de la Recherche Scientifique, Marcoussis 91460 (France); Hashimoto, H. [Department of EECE, Chuo University 1-13-27 Kasuga, Bunkyo-ku, Tokyo (Japan)

2012-12-15

372

Analog and numerical experiments investigating force chain influences on bed conditions in granular flows  

NASA Astrophysics Data System (ADS)

Granular flows are fundamental processes in several terrestrial and planetary natural events; including surficial flows on volcanic edifices, debris flows, landslides, dune formation, rock falls, sector collapses, and avalanches. Often granular flows can be two-phase, whereby interstitial fluids occupy void space within the particulates. The mobility of granular flows has received significant attention, however the physics that govern their internal behavior remain poorly understood. Here we extend upon previous research showing that force chains can transmit extreme localized forces to the substrates of free surface granular flows, and we combine experimental and computational approaches to further investigate the forces at the bed of simplified granular flows. Analog experiments resolve discrete bed forces via a photoelastic technique, while numerical experiments validate laboratory tests using discrete element model (DEM) simulations. The current work investigates (1) the role of distributed grain sizes on force transmission via force chains, and (2) how the inclusion of interstitial fluids effects force chain development. We also include 3D numerical simulations to apply observed 2D characteristics into real world perspective, and ascertain if the added dimension alters force chain behavior. Previous research showed that bed forces generated by force chain structures can transiently greatly exceed (by several 100%) the bed forces predicted from continuum approaches, and that natural materials are more prone to excessive bed forces than photoelastic materials due to their larger contact stiffnesses. This work suggests that force chain activity may play an important role in the bed physics of dense granular flows by influencing substrate entrainment. Photoelastic experiment image showing force chains in gravity driven granular flow.

Estep, J.; Dufek, J.

2013-12-01

373

SI traceable calibration of an instrumented indentation sensor spring constant using electrostatic force  

SciTech Connect

We present a measurement scheme for creating reference electrostatic forces that are traceable to the International System of Units. This scheme yields reference forces suitable for calibrating the force sensitivity of instrumented indentation machines and atomic force microscopes. Forces between 10 and 200 {mu}N were created and expressed in terms of the voltage, length, and capacitance between a pair of interacting electrodes. The electrodes comprised an electrically conductive sphere mounted as a tip on an instrumented indentation sensor, and a planar counterelectrode fixed to a sample stage in close proximity to the sphere. For comparison, we applied mechanical forces of similar magnitudes, first using deadweights and then using a reference force sensor. The deflection of the sensor due to the various applied forces was measured using an interferometer. A spring constant for the sensor was computed from the observed records of force versus displacement. Each procedure yielded a relative standard uncertainty of approximately 1%; however, the electrostatic technique is scalable and could provide traceable reference forces as small as a few hundred piconewtons, a range far below anything yet achieved using deadweights.

Chung, Koo-Hyun; Scholz, Stefan; Shaw, Gordon A.; Kramar, John A.; Pratt, Jon R. [Manufacturing Engineering Laboratory, National Institute of Standards and Technology, Gaithersburg, Maryland 20899 (United States)

2008-09-15

374

Magnetic Force Three Wires Model  

NSDL National Science Digital Library

The Magnetic Force Three Wires model investigates the force between long straight current-carrying wires. Initially, the simulation shows a cross-section view of three long straight parallel wires, each on the corner of an equilateral triangle. The wires carry currents that have different magnitudes, and the currents are directed either into or out of the page. The task in this simulation is to rank the wires based on the magnitude of their currents, from largest to smallest. The Magnetic Force Three Wires model was created using the Easy Java Simulations (EJS) modeling tool. It is distributed as a ready-to-run (compiled) Java archive. Double clicking the ejs_bu_Three_Wires.jar file will run the program if Java is installed. This is part of a collection of similar tutorial simulations created by the author.

Duffy, Andrew

2009-10-20

375

Nuclear force in Lattice QCD  

E-print Network

We perform the quenched lattice QCD analysis on the nuclear force (baryon-baryon interactions). We employ $20^3\\times 24$ lattice at $\\beta=5.7$ ($a\\simeq 0.19$ fm) with the standard gauge action and the Wilson quark action with the hopping parameters $\\kappa=0.1600, 0.1625, 0.1650$, and generate about 200 gauge configurations. We measure the temporal correlators of the two-baryon system which consists of heavy-light-light quarks. We extract the inter-baryon force as a function of the relative distance $r$. We also evaluate the contribution to the nuclear force from each ``Feynman diagram'' such as the quark-exchange diagram individually, and single out the roles of Pauli-blocking effects or quark exchanges in the inter-baryon interactions.

T. T. Takahashi; T. Doi; H. Suganuma

2006-01-05

376

The mouse forced swim test.  

PubMed

The forced swim test is a rodent behavioral test used for evaluation of antidepressant drugs, antidepressant efficacy of new compounds, and experimental manipulations that are aimed at rendering or preventing depressive-like states. Mice are placed in an inescapable transparent tank that is filled with water and their escape related mobility behavior is measured. The forced swim test is straightforward to conduct reliably and it requires minimal specialized equipment. Successful implementation of the forced swim test requires adherence to certain procedural details and minimization of unwarranted stress to the mice. In the protocol description and the accompanying video, we explain how to conduct the mouse version of this test with emphasis on potential pitfalls that may be detrimental to interpretation of results and how to avoid them. Additionally, we explain how the behaviors manifested in the test are assessed. PMID:22314943

Can, Adem; Dao, David T; Arad, Michal; Terrillion, Chantelle E; Piantadosi, Sean C; Gould, Todd D

2012-01-01

377

Air Force Historical Research Agency  

NSDL National Science Digital Library

Started in World War II in Washington, D.C., the Air Force Historical Research Agency (AFHRA) has the largest collection of US military aviation documents, with more than 70,000,000 pages all told within their holdings. Since 1949, it has been housed at Maxwell Air Force Base in Alabama, and is open to the general public, military students, researchers, and scholars. Visitors will find some interesting reading under the Studies tab, which includes "Numbered USAF Historical Studies", some of which are designated Secret, and others Unclassified. Also interesting are the "Short Studies on Recent Operations" available in PDF, and including such topics as "Weather in Air Campaigns, 1990-2003" and "The U.S. Air Force Response to Hurricane Katrina". Nearby, under "Other Studies", visitors will find "A Study of Females on Minuteman/Peacekeeper Crews, 31 January 1985" and "Chronology: 100 Years of Flight".

378

Forced Oscillations of Supported Drops  

NASA Technical Reports Server (NTRS)

Oscillations of supported liquid drops are the subject of wide scientific interest, with applications in areas as diverse as liquid-liquid extraction, synthesis of ceramic powders, growing of pure crystals in low gravity, and measurement of dynamic surface tension. In this research, axisymmetric forced oscillations of arbitrary amplitude of viscous liquid drops of fixed volume which are pendant from or sessile on a rod with a fixed or moving contact line and surrounded by an inviscid ambient gas are induced by moving the rod in the vertical direction sinusiodally in time. In this paper, a preliminary report is made on the computational analysis of the oscillations of supported drops that have 'clean' interfaces and whose contact lines remain fixed throughout their motions. The relative importance of forcing to damping can be increased by either increasing the amplitude of rod motion A or Reynolds number Re. It is shown that as the ratio of forcing to damping rises, for drops starting from an initial rest state a sharp increase in deformation can occur when they are forced to oscillate in the vicinity of their resonance frequencies, indicating the incipience of hysteresis. However, it is also shown that the existence of a second stable limit cycle and the occurrence of hysteresis can be observed if the drop is subjected to a so-called frequency sweep, where the forcing frequency is first increased and then decreased over a suitable range. Because the change in drop deformation response is abrupt in the vicinity of the forcing frequencies where hysteresis occurs, it should be possible to exploit the phenomenon to accurately measure the viscosity and surface tension of the drop liquid.

Wilkes, Edward D.; Basaran, Osman A.

1996-01-01

379

Independent measurements of force and position in atomic force microscopy  

NASA Astrophysics Data System (ADS)

Historically, precise vertical control of an atomic force microscope (AFM) tip while it is disengaged from the surface has been an unsolved problem. By separately scattering a pair of lasers off the tip and a fiducial mark in the sample, we locally measured and thereby actively controlled tip and sample position in three dimensions, achieving atomic-scale (0.1 nm) precision at ambient conditions. We also measured cantilever deflection (force) using the standard optical-lever- arm geometry. Both detection techniques were used to determine the vertical location of the surface (z = 0) relative to the AFM tip assembly. The difference in these vertical determinations was 0.0 +/- 0.3 nm (mean +/- S.D.; N = 86). This agreement allowed us to establish an optically based reference frame to measure the vertical position of the tip relative to the surface. This reference frame is insensitive to long-term mechanical drift of the AFM assembly and complementary to the cantilever deflection sensing, which measures force. We expect this dual z-detection to be useful in a broad array of applications that demand precise tip-sample control, including tip-based nanofabrication and single-molecule force spectroscopy.

Churnside, Allison B.; King, Gavin M.; Perkins, Thomas T.

2009-08-01

380

Fluid forces on circular cylinders  

E-print Network

and ~ia force and, several 1'orce anomalies which sx'ise frdm tbe flow conditions imposed by the flaM boundaries. The surface anomaly, 4Fs is the fame anomaly 4us to penetration of the cyl1nder through ths air-fluid interface and is the remelt of bow... of WuZZR OF SCINNCZ l4sy 19+ l4aJor Subject - Physical Oceanography FLUID FORCES CIRCULAR CYLIEDERS A Thesis Ry Robert G. Dean Approved as to style and oontent bye Cha n of Coaaittee Read of De n Contents Introduction Apparatus Procedure...

Dean, Robert G

1956-01-01

381

Forced synchronization of quasiperiodic oscillations  

NASA Astrophysics Data System (ADS)

A model of a generator of quasiperiodic oscillations forced by a periodic pulse sequence is studied. We analyze synchronization when the autonomous generator demonstrates periodic, quasiperiodic, respective weakly chaotic oscillations. For the forced quasiperiodic oscillations a picture of synchronization, consisting of small-scale and large-scale structures was uncovered. It even includes the existence of stable the three-frequency tori. For the regime of weak chaos a partial destruction of this features and of the regime of three-frequency tori are found.

Stankevich, N. V.; Kurths, J.; Kuznetsov, A. P.

2015-01-01

382

Illinois PER Interactive Examples: Forces  

NSDL National Science Digital Library

This is an interactive homework problem for introductory physics students relating to vector addition. Given a free-body diagram depicting three forces acting on an object, students are required to find the magnitude of the net force. A user-activated "help" sequence is provided for each step of the problem-solving, from conceptual analysis through quantitative calculation. To promote critical thinking, immediate feedback is received for both correct and incorrect responses. This item is part of a larger collection of interactive homework problems for introductory physics.

Gladding, Gary

2008-09-12

383

Automatic HTS force measurement instrument  

DOEpatents

A device is disclosed for measuring the levitation force of a high temperature superconductor sample with respect to a reference magnet includes a receptacle for holding several high temperature superconductor samples each cooled to superconducting temperature. A rotatable carousel successively locates a selected one of the high temperature superconductor samples in registry with the reference magnet. Mechanism varies the distance between one of the high temperature superconductor samples and the reference magnet, and a sensor measures levitation force of the sample as a function of the distance between the reference magnet and the sample. A method is also disclosed. 3 figs.

Sanders, S.T.; Niemann, R.C.

1999-03-30

384

Automatic HTS force measurement instrument  

DOEpatents

A device for measuring the levitation force of a high temperature superconductor sample with respect to a reference magnet includes a receptacle for holding several high temperature superconductor samples each cooled to superconducting temperature. A rotatable carousel successively locates a selected one of the high temperature superconductor samples in registry with the reference magnet. Mechanism varies the distance between one of the high temperature superconductor samples and the reference magnet, and a sensor measures levitation force of the sample as a function of the distance between the reference magnet and the sample. A method is also disclosed.

Sanders, Scott T. (Valparaiso, IN); Niemann, Ralph C. (Downers Grove, IL)

1999-01-01

385

Observation of Peak Neoclassical Toroidal Viscous Force in the DIII-D Tokamak  

SciTech Connect

Observation of a theoretically predicted peak in the neoclassical toroidal viscosity (NTV) force as a function of toroidal plasma rotation rate {Omega} is reported. The NTV was generated by applying n=3 magnetic fields from internal coils to low {Omega} plasmas produced with nearly balanced neutral beam injection. Locally, the peak corresponds to a toroidal rotation rate {Omega}{sub 0} where the radial electric field E{sub r} is near zero as determined by radial ion force balance.

Cole, A. J.; Callen, J. D.; Hegna, C. C. [University of Wisconsin, Madison, Wisconsin 53706-1609 (United States); Solomon, W. M. [Princeton Plasma Physics Laboratory, Post Office Box 451, Princeton, New Jersey 08543-0451 (United States); Garofalo, A. M. [General Atomics, Post Office Box 85608, San Diego, California 92186-5608 (United States); Lanctot, M. J.; Reimerdes, H. [Columbia University, 2960 Broadway, New York, New York 10027-1754 (United States)

2011-06-03

386

May the Force Be with You!  

ERIC Educational Resources Information Center

Students have a difficult time understanding force, especially when dealing with a moving object. Many forces can be acting on an object at the same time, causing it to stay in one place or move. By directly observing these forces, students can better understand the effect these forces have on an object. With a simple, student-built device called

Young, Timothy; Guy, Mark

2011-01-01

387

Ambulatory measurement of ground reaction forces  

Microsoft Academic Search

The measurement of ground reaction forces is important in the biomechanical analysis of gait and other motor activities. Many applications require full ambulatory measurement of these forces, but this is not supported by current measurement systems. We propose the use of two six-degrees-of-freedom force and moment sensors under each shoe, which enables the ambulatory measurement of ground reaction forces and

Peter H. Veltink; Christian Liedtke; Ed Droog; Kooij van der Herman

2005-01-01

388

Solvent-induced forces in protein folding  

SciTech Connect

The solvent-induced forces between various groups on the protein are examined. It is found that the intramolecular hydrophilic forces are likely to be the strongest forces mediated through the solvent. It is argued that these are probably the most important solvent-induced driving forces in the process of protein folding.

Ben-Naim, A. (Hebrew Univ., Jerusalem (Israel))

1990-08-23

389

Climate Forcings in the Industrial Era  

Microsoft Academic Search

The forcings that drive long-term climate change are not known with an accuracy sufficient to define future climate change. Anthropogenic greenhouse gases (GHGs), which are well measured, cause a strong positive (warming) forcing. But other, poorly measured, anthropogenic forcings, especially changes of atmospheric aerosols, clouds, and land-use patterns, cause a negative forcing that tends to offset greenhouse warming. One consequence

James E. Hansen; Makiko Sato; Andrew Lacis; Reto Ruedy; Ina Tegen; Elaine Matthews

1998-01-01

390

Traction forces generated by locomoting keratocytes  

Microsoft Academic Search

Traction forces produced by moving fibro- blasts have been observed as distortions in flexible substrata including wrinkling of thin, silicone rubber films. Traction forces generated by fibroblast lamellae were thought to represent the forces required to move the cell forwards. However, traction forces could not be detected with faster moving cell types such as leu- kocytes and growth cones (Harris,

Juliet Lee; Michelle Leonard; Tun Oliver; Akira Ishihara; Ken Jacobson

1994-01-01

391

NTNU Java: Free-Body Force Diagram  

NSDL National Science Digital Library

This applet illustrates the forces on a block on an inclined plane. A free-body diagram shows the gravitational, normal, frictional and net force vectors. The weight, angle of the plane, and coefficient of friction can be changed by the user. The user can also apply an external force to the block. The motion resulting from the forces is not shown.

Hwang, Fu-Kwun

2005-02-07

392

Articulated Multimedia Physics, Lesson 7, Combining Forces.  

ERIC Educational Resources Information Center

As the seventh lesson of the Articulated Multimedia Physics Course, instructional materials are presented in this study guide with relation to the force combination. The topics are concerned with the definition and units of forces, sliding forces on inclined planes, and the equilibrant of two or more forces. The content is arranged in scrambled

New York Inst. of Tech., Old Westbury.

393

Micro Handling Devices Supported by Electrostatic Forces  

Microsoft Academic Search

The handling of micro parts made of dielectric material can be affected by electrostatic forces. This work presents new handling devices taking advantage of electrostatic forces. These forces are generated by simple configurations of electrodes or by charges located on surfaces of insulators. High resolution force measurements show electrostatic effects such as gas discharges and leak currents. Active neutralization was

J. Hesselbach; J. Wrege; A. Raatz

2007-01-01

394

Mingei International Museum  

NSDL National Science Digital Library

Mingei is Japanese for "art of the people" and is used to describe everyday items that are also wonderful arts and crafts. The arts of daily lives are represented at the Mingei International Museum, but the museum doesn't only highlight the everyday art of the Japanese, as there is art from cultures and countries around the world and from historic and contemporary artists. Visitors can see many of the objects in their digital form on their website. The artist in the current exhibition "Sonabai: Another Way of Seeing", is clay sculptor Sonabai Rajawar, and there are also some selections from four artists who studied under Rajawar. Her clay animals are whimsical, yet were born of her forced isolation in rural India for 15 years. She has since been honored in India and around the world. There are several other exhibitions visitors can view online, along with a calendar of events, a place to sign up for the museum's newsletter, and additional links to past and future exhibits.

395

Probing protein-protein interactions by dynamic force correlated spectroscopy (FCS)  

E-print Network

We develop a formalism for single molecule dynamic force spectroscopy to map the energy landscape of protein-protein complex ($P_1$$P_2$). The joint distribution $P(\\tau_1,\\tau_2)$ of unbinding lifetimes $\\tau_1$ and $\\tau_2$ measurable in a compression-tension cycle, which accounts for the internal relaxation dynamics of the proteins under tension, shows that the histogram of $\\tau_1$ is not Poissonian. The theory is applied to the forced unbinding of protein $P_1$, modeled as a wormlike chain, from $P_1$$P_2$. We propose a new class of experiments which can resolve the effect of internal protein dynamics on the unbinding lifetimes.

V. Barsegov; D. Thirumalai

2005-09-05

396

21 11 13 INTERNATIONAL  

E-print Network

31 E 32 F 32 #12; iv INTERNATIONAL ERGONOMICS ASSOCIATION #12; 3 INTERNATIONAL ERGONOMICS ASSOCIATION CODE OF CONDUCT ERGONOMICS ASSOCIATION (2006) http://www.iea.cc/browse.php?contID=international_ergonomics_association A6

Yamamoto, Hirosuke

397

Internal auditing practices and internal control system  

Microsoft Academic Search

Purpose Two main objectives and they are: to determine whether the internal audit department of the companies listed in the Bursa Malaysia complies with the Standards for the Professional Practice of Internal Auditors IIA (2000); and, to determine whether compliance to SPPIA will affect the quality of the internal control system of the company. Design\\/methodology\\/approach Two sets of

Faudziah Hanim Fadzil; Hasnah Haron; Muhamad Jantan

2005-01-01

398

Muon Task Force Valeri Lebedev  

E-print Network

Possible experiments Next generation (g-2) if motivated by next round (theory, LHC) Next generation -to of experiments High energy, small repetition rate (~10-100 Hz, fast extraction from ring) (g-2) Small energyMuon Task Force Valeri Lebedev Sergei Striganov and Vitaly Pronskikh Contents Introduction Basics

McDonald, Kirk

399

Isometric Force Regulation in Children.  

ERIC Educational Resources Information Center

Isometric pinch force regulation was investigated in children and adults using a visuo-motor tracking paradigm. Younger children aged 5-7 years performed significantly worse than older children aged 9-11 years and adults in terms of an overall error score as well as a correlation score, which is believed to reflect the ability to predict the

Lazarus, Jo-Anne C.; And Others

1995-01-01

400

Lorentz Force Accelerator Technology Investigated  

NASA Technical Reports Server (NTRS)

The NASA Glenn Research Center is developing Lorenz force accelerators (LFAs) for a wide variety of space applications. These range from the precision control of formation-flying spacecraft to the primary propulsion system for very high power interplanetary spacecraft. The specific thruster technologies being addressed are pulsed plasma thrusters (PPT) and magnetoplasmadynamic (MPD) thrusters.

Pencil, Eric J.; LaPointe, Michael R.; Arrington, Lynn A.; Kamhawi, Hani; Benson, Scott W.; Hoskins, W. Andrew

2004-01-01

401

Force Components, the Last Straw.  

ERIC Educational Resources Information Center

An activity in which students use a rubber band and flexible straws to pull a dynamics cart so that the cart has a consistent angle and, therefore, a consistent horizontal component of force is described. A copy of the handout for the activity is included. (KR)

Fox, Kenneth

1991-01-01

402

Force10 P10 Evaluation  

SciTech Connect

The lack of an acceptable intrusion monitoring solution limits the deployment of 10GE (10 Gigabit-per-second Ethernet) technology across the LLNL's unclassified network infrastructure. The desire to operate at 10GE motivates us to evaluate the functionality and performance of a 10GE intrusion monitoring solution, the Force10 P10.

Allen, J; Goldstone, R; Instenes, S; Lawver, B

2007-06-08

403

Nuclear Force from String Theory  

E-print Network

We compute nuclear force in a holographic model of QCD on the basis of a D4-D8 brane configuration in type IIA string theory. Repulsive core of nucleons is quite important in nuclear physics, but its origin has not been well-understood in strongly-coupled QCD. We find that string theory via gauge/string duality deduces this repulsive core at short distance between nucleons. Since baryons in the model are realized as solitons given by Yang-Mills instanton configuration on flavor D8-branes, ADHM construction of two instantons probes well the nucleon interaction at short scale, which provides the nuclear force quantitatively. We obtain, as well as a tensor force, a central force which is strongly repulsive as suggested in experiments and lattice results. In particular, the nucleon-nucleon potential V(r) (as a function of the distance) scales as 1/r^2, which is peculiar to the holographic model. We compare our results with one-boson exchange model using the nucleon-nucleon-meson coupling obtained in our previous paper (arXiv:0806.3122).

Koji Hashimoto; Tadakatsu Sakai; Shigeki Sugimoto

2009-01-28

404

Atomic Force Microscopy Video Module  

NSDL National Science Digital Library

This resource, produced by the Center for Heirarchical Manufacturing at the University of Massachusetts Amherst, is part of the "Nanotechnology Education Curriculum Development Program." It is free to the public and offers information on atomic force microscopy, signal processing, nanotechnology and general instrumentation.

Calm, Yitzi; Ke, Huaje

2011-02-15

405

Driving Forces of Informal Sanctions  

Microsoft Academic Search

Informal sanctions are a major determinant of a society's social capital because they are key to the enforcement of implicit agreements and social norms. Yet, little is known about the driving forces behind informal sanctions. We systematically examine the determinants of informal sanctions by a large number of experiments. Our findings show that the violation of fairness principles is the

Armin Falk; Ernst Fehr; Urs Fischbacher

2001-01-01

406

Physics 2000: The Electric Force  

NSDL National Science Digital Library

This webpage demonstrates electric force exerted by positive and negative charges through a simulation of the behaviour of an electron in the presence of a proton. The concept is explained in the form of a conversation between two people to make learning more interesting. This webpage is a part of an extensive collection of physics tutorials.

Physics 2000

2006-07-06

407

Communications Measurement of the Force  

E-print Network

that the measurements taken represent the force of the plasma jet and not an extraneous signal, the balance was tested. BALANCE BEAM ~~ ELECTRODE y__r' S TEST PLATE TORSION BAR 5 CM DISPLACEMENT TRANSDUCER Fig. 2- Schematic of torsion balance apparatus. The counterweight, dash- pot, ground cable, test plate insulator, electrostatic

Eagar, Thomas W.

408

Coffee Cup Atomic Force Microscopy  

ERIC Educational Resources Information Center

In this activity, students use a model created from a coffee cup or cardstock cutout to explore the working principle of an atomic force microscope (AFM). Students manipulate a model of an AFM, using it to examine various objects to retrieve topographic data and then graph and interpret results. The students observe that movement of the AFM

Ashkenaz, David E.; Hall, W. Paige; Haynes, Christy L.; Hicks, Erin M.; McFarland, Adam D.; Sherry, Leif J.; Stuart, Douglas A.; Wheeler, Korin E.; Yonzon, Chanda R.; Zhao, Jing; Godwin, Hilary A.; Van Duyne, Richard P.

2010-01-01

409

Forces Between Electrical Current Elements  

NASA Astrophysics Data System (ADS)

The momentum of a charged particle is p*=mv*-qA*, where m, v*, q and A* are respectively mass, velocity, charge and vector potential, and * denotes vector. Hence current element I'ds'* exerts a force on Ids*: ddF*=b(II'/r3)(r*.ds*)ds'*=ddF*(magnetic)+b(II'/r3)(ds*.ds'*)r*(nonmagnetic), where b=10-7 Newton/Ampere2. From ds'* to ds* is r*. This causes a nonuniform charge distribution along the circuit(s) containing Ids* and I'ds'* whose field transfers ddF* from conduction electrons to ions. The line integral of ddF* is tensile between points of a rectilinear portion of a circuit. The Lorentz force and Ampere's third law of magnetostatic force are invalid if ddF* is confirmed by a nonzero torque of a Marinov motor. If Ids* has velocity w* relative to I'ds'*: ddF* acts on conduction electrons of ds* as when w=0 and also acts on electrons and nuclei of ions of ds* as current elements w*dq=Dw*ds; D is linear charge density of ions. Resulting polarization by equal but opposite forces on electrons and nuclei of ions transfers ddF* from conduction electrons to ions. J. P. Wesley's intuitive assumption is justified.

Driscoll, Robert B.

2003-04-01

410

Unifying all classical Force Equations  

Microsoft Academic Search

It can be shown that all classical force equations can be derived from one another by means of a new definition of discrete electric and magnetic fields for localized massive particles ((5)), and that all of them amount to Newton's F=ma fundamental acceleration equation.

Andr Michaud

411

Determining the shear angle, forces, and sizes of shearing elements during metal cutting  

NASA Astrophysics Data System (ADS)

A new solution for the shear angle is proposed which is a generalization of the solution Lee-Shaffer solution and allows the determination of the cutting force and the shearing-element size. Merchants experimental data are processed taking into account the resistance force at the cutting edge, and it is shown that accounting for this force leads to the need to increase the internal friction angle in the calculated dependences in order to match theory with experiment. It is shown that the obtained theoretical results agree well with experimental results.

Kovrizhnykh, A. M.

2009-01-01

412

High-resolution noncontact atomic force microscopy.  

PubMed

Progress in nanoscience and nanotechnology requires tools that enable the imaging and manipulation of matter at the atomic and molecular scale. During the last two decades or so, scanning probe-based techniques have proven to be particularly versatile in this regard. Among the various probe-based approaches, atomic force microscopy (AFM) stands out in many ways, including the total number of citations and the breadth of possible applications, ranging from materials characterization to nanofabrication and biological studies. However, while nanometer scale operation in different environments became routine, atomic resolution imaging remained elusive for a long time. The reason for this initial deficiency was that contact with the sample blunts atomically sharp tips, which are mandatory for successful atomic resolution imaging. This problem was overcome in the mid-1990s with the introduction of noncontact atomic force microscopy (NC-AFM), which represents a version of AFM where the cantilever is oscillated close to the sample surface without actually 'touching' it. This allows the preservation of the atomic sharpness of the tip while interaction-induced changes in the cantilever's resonance frequency are used to quantify the tip-sample distance. Since then, progress has been steady and includes the development of commercial instruments as well as the addition of many new capabilities beyond imaging, such as the identification and manipulation of individual atoms. A series of annual international conferences, starting in Osaka in 1998, have contributed significantly to this outstanding performance. The program of the most recent conference from this series, held in Madrid on 15-19 September 2008, reflects the maturity of this field, with an increasing number of groups developing strong activities that involve novel approaches and applications covering areas well beyond the original vacuum-based imaging. In this special issue of Nanotechnology we present a selection of original papers authored by many of the leading groups in the field with the goal of providing a well-balanced overview on the state-of-the-art in this rapidly evolving field. These papers, many of which are based on notable presentations given during the Madrid conference, feature highlights such as (1) the development of sophisticated force spectroscopy procedures that are able to map the complete 3D tip-sample force field on different surfaces; (2) the considerable resolution improvement of Kelvin probe force microscopy (reaching, in some cases, the atomic scale), which is accompanied by a thorough, quantitative understanding of the contrast observed; (3) the perfecting of atomic resolution imaging on insulating substrates, which helps reshape our microscopic understanding of surface properties and chemical activity of these surfaces; (4) the description of instrumental and methodological developments that pave the way to the atomic-scale characterization of magnetic and electronic properties of nanostructures, and last but not least (5) the extension of dynamic imaging modes to high-resolution operation in liquids, ultimately achieving atomic resolution. The latter developments are already having a significant impact in the highly competitive field of biological imaging under physiological conditions. This special issue of Nanotechnology would not have been possible without the highly professional support from Nina Couzin, Amy Harvey, Alex Wotherspoon and the entire Nanotechnology team at IOP Publishing. We are thankful for their help in pushing this project forward. We also thank the authors who have contributed their excellent original articles to this issue, the referees whose comments have helped make the issue an accurate portrait of this rapidly moving field, and the entire NC-AFM community that continues to drive NC-AFM to new horizons. PMID:19531843

Prez, Rubn; Garca, Ricardo; Schwarz, Udo

2009-07-01

413

IEC measurement standards for ultrasonic hydrophones and radiation force balances  

NASA Astrophysics Data System (ADS)

Acoustic output measurements of medical ultrasonic equipment are usually performed in water and using two widely established methods: ultrasonic power measurement with a radiation force balance and acoustic pressure measurement with an ultrasonic hydrophone. The International Electrotechnical Commission (IEC) has published a number of International Standards on both methods, prepared by its Technical Committee 87 ''Ultrasonics.'' These are discussed and future standardization trends are presented. The basic standard for ultrasonic power measurements is IEC 61161. It recommends using a radiation force balance and specifies the relevant technical properties and sources of uncertainty. It is currently envisaged to revise this standard and to include particular recommendations for the power range up to 20 W which have recently been worked out in an international cooperation of national metrology institutes. Hydrophone standards have continuously been developed over many years. The most recent one is IEC 62092 which extends the upper frequency limit of hydrophone standarization from 15 MHz to 40 MHz. The current trend is to reorganize all existing hydrophone standards and to find a new scheme of three parallel standards dealing with hydrophone properties, hydrophone use, and hydrophone calibration.

Beissner, K.

2002-11-01

414

What drives activation-dependent shifts in the force-length curve?  

PubMed

Skeletal muscles are rarely recruited maximally during movement. However, much of our understanding of muscle properties is based on studies using maximal activation. The effect of activation level on skeletal muscle properties remains poorly understood. Muscle optimum length increases with decreased activation; however, the mechanism responsible is unclear. Here, we attempted to determine whether length-dependent calcium effects, or the effect of absolute force underpin this shift. Fixed-end contractions were performed in frog plantaris muscles at a range of lengths using maximal tetanic (high force, high calcium), submaximal tetanic (low force, high calcium) and twitch (low force, low calcium) stimulation conditions. Peak force and optimum length were determined in each condition. Optimum length increased with decreasing peak force, irrespective of stimulation condition. Assuming calcium concentration varied as predicted, this suggests that absolute force, rather than calcium concentration, underpins the effect of activation level on optimum length. We suggest that the effect of absolute force is due to the varying effect of the internal mechanics of the muscle at different activation levels. These findings have implications for our understanding of in vivo muscle function and suggest that mechanical interactions within muscle may be important determinants of force at lower levels of activation. PMID:25252838

Holt, Natalie C; Azizi, E

2014-09-01

415

Conventional forces and arms control: Technology and strategy in a changing world  

SciTech Connect

To address the implications of changes for future roles of conventional forces and to assess the technology implications of future strategies, force requirements, and conventional arms control agreements, the Center for National Security Studies in cooperation with the Defense Research and Applications Directorate of the Los Alamos National Laboratory held a conference on Conventional Forces and Arms Control: Technology and Strategy in a Changing World'' at Los Alamos from September 25--27, 1989. The distinguished participants from government, industry, and academia in the United States and Western Europe addressed such issues as: What are the implications of geopolitical and technological trends for international security and stability How will these global changes affect US and allied strategies and force structure, especially the requirements for conventional, nonnuclear forces What will be the role of and rationale for conventional forces in the context of current and prospective allied security requirements How can the West assure it will have the forces necessary for its security How will technological developments influence the structure of tomorrow's conventional forces What impacts will arms reductions have on future systems and force structures What are the prospects for the development and deployment in weapon systems of future conventional military technologies, in light of existing and potential political, economic, bureaucratic, and other impediments

Pilat, J.F.; White, P.C.

1990-06-01

416

Advances in Magnetic Force Microscopy John Moreland, Chairman Magnetic dissipation force microscopy studies of magnetic  

E-print Network

Advances in Magnetic Force Microscopy John Moreland, Chairman Magnetic dissipation force microscopy dissipation force microscopy to magnetic materials. Energy dissipation is measured by simultaneous monitoring0021-8979 98 48611-0 Magnetic dissipation force microscopy1­4 is a working mode of an ac magnetic force

Grütter, Peter

417

Measuring bow force in bowed string performance: Theory and implementation of a bow force sensor  

E-print Network

Measuring bow force in bowed string performance: Theory and implementation of a bow force sensor M of the force exerted by the bow on the string (bow force) during violin performance. The bow force is deduced main control parameters in bowed string playing, the two others being bow velocity and bow- bridge

Paris-Sud XI, Université de

418

Dynamic Surface Force Measurement. 2. Friction and the Atomic Force Microscope  

E-print Network

Dynamic Surface Force Measurement. 2. Friction and the Atomic Force Microscope Phil Attard* Ian of force measurement with the atomic force microscope are analyzed in detail. The effective spring constant of the piezoelectric drive motor and position detector used in the atomic force microscope. It is shown that hysteresis

Attard, Phil

419

Lorentz force actuation of a heated atomic force microscope cantilever.  

PubMed

We report Lorentz force-induced actuation of a silicon microcantilever having an integrated resistive heater. Oscillating current through the cantilever interacts with the magnetic field around a NdFeB permanent magnet and induces a Lorentz force that deflects the cantilever. The same current induces cantilever heating. With AC currents as low as 0.2 mA, the cantilever can be oscillated as much as 80 nm at resonance with a DC temperature rise of less than 5 C. By comparison, the AC temperature variation leads to a thermomechanical oscillation that is about 1000 times smaller than the Lorentz deflection at the cantilever resonance. The cantilever position in the nonuniform magnetic field affects the Lorentz force-induced deflection, with the magnetic field parallel to the cantilever having the largest effect on cantilever actuation. We demonstrate how the cantilever actuation can be used for imaging, and for measuring the local material softening temperature by sensing the contact resonance shift. PMID:22237044

Lee, Byeonghee; Prater, Craig B; King, William P

2012-02-10

420

Aerosol Absorption and Radiative Forcing  

NASA Technical Reports Server (NTRS)

We present a comprehensive examination of aerosol absorption with a focus on evaluating the sensitivity of the global distribution of aerosol absorption to key uncertainties in the process representation. For this purpose we extended the comprehensive aerosol-climate model ECHAM5-HAM by effective medium approximations for the calculation of aerosol effective refractive indices, updated black carbon refractive indices, new cloud radiative properties considering the effect of aerosol inclusions, as well as by modules for the calculation of long-wave aerosol radiative properties and instantaneous aerosol forcing. The evaluation of the simulated aerosol absorption optical depth with the AERONET sun-photometer network shows a good agreement in the large scale global patterns. On a regional basis it becomes evident that the update of the BC refractive indices to Bond and Bergstrom (2006) significantly improves the previous underestimation of the aerosol absorption optical depth. In the global annual-mean, absorption acts to reduce the shortwave anthropogenic aerosol top-of-atmosphere (TOA) radiative forcing clear-sky from -0.79 to -0.53 W m(sup -2) (33%) and all-sky from -0.47 to -0.13W m(sup -2 (72%). Our results confirm that basic assumptions about the BC refractive index play a key role for aerosol absorption and radiative forcing. The effect of the usage of more accurate effective medium approximations is comparably small. We demonstrate that the diversity in the AeroCom land-surface albedo fields contributes to the uncertainty in the simulated anthropogenic aerosol radiative forcings: the usage of an upper versus lower bound of the AeroCom land albedos introduces a global annual-mean TOA forcing range of 0.19W m(sup -2) (36%) clear-sky and of 0.12W m(sup -2) (92%) all-sky. The consideration of black carbon inclusions on cloud radiative properties results in a small global annual-mean all-sky absorption of 0.05W m(sup -2) and a positive TOA forcing perturbation of 0.02W m(sup -2). The long-wave aerosol radiative effects are small for anthropogenic aerosols but become of relevance for the larger natural dust and sea-salt aerosols.

Stier, Philip; Seinfeld, J. H.; Kinne, Stefan; Boucher, Olivier

2007-01-01

421

Aerosol absorption and radiative forcing  

NASA Astrophysics Data System (ADS)

We present a comprehensive examination of aerosol absorption with a focus on evaluating the sensitivity of the global distribution of aerosol absorption to key uncertainties in the process representation. For this purpose we extended the comprehensive aerosol-climate model ECHAM5-HAM by effective medium approximations for the calculation of aerosol effective refractive indices, updated black carbon refractive indices, new cloud radiative properties considering the effect of aerosol inclusions, as well as by modules for the calculation of long-wave aerosol radiative properties and instantaneous aerosol forcing. The evaluation of the simulated aerosol absorption optical depth with the AERONET sun-photometer network shows a good agreement in the large scale global patterns. On a regional basis it becomes evident that the update of the BC refractive indices to Bond and Bergstrom (2006) significantly improves the previous underestimation of the aerosol absorption optical depth. In the global annual-mean, absorption acts to reduce the short-wave anthropogenic aerosol top-of-atmosphere (TOA) radiative forcing clear-sky from -0.79 to -0.53 W m-2 (33%) and all-sky from -0.47 to -0.13 W m-2 (72%). Our results confirm that basic assumptions about the BC refractive index play a key role for aerosol absorption and radiative forcing. The effect of the usage of more accurate effective medium approximations is comparably small. We demonstrate that the diversity in the AeroCom land-surface albedo fields contributes to the uncertainty in the simulated anthropogenic aerosol radiative forcings: the usage of an upper versus lower bound of the AeroCom land albedos introduces a global annual-mean TOA forcing range of 0.19 W m-2 (36%) clear-sky and of 0.12 W m-2 (92%) all-sky. The consideration of black carbon inclusions on cloud radiative properties results in a small global annual-mean all-sky absorption of 0.05 W m-2 and a positive TOA forcing perturbation of 0.02 W m-2. The long-wave aerosol radiative effects are small for anthropogenic aerosols but become of relevance for the larger natural dust and sea-salt aerosols.

Stier, P.; Seinfeld, J. H.; Kinne, S.; Boucher, O.

2007-10-01

422

Aerosol absorption and radiative forcing  

NASA Astrophysics Data System (ADS)

We present a comprehensive examination of aerosol absorption with a focus on evaluating the sensitivity of the global distribution of aerosol absorption to key uncertainties in the process representation. For this purpose we extended the comprehensive aerosol-climate model ECHAM5-HAM by effective medium approximations for the calculation of aerosol effective refractive indices, updated black carbon refractive indices, new cloud radiative properties considering the effect of aerosol inclusions, as well as by modules for the calculation of long-wave aerosol radiative properties and instantaneous aerosol forcing. The evaluation of the simulated aerosol absorption optical depth with the AERONET sun-photometer network shows a good agreement in the large scale global patterns. On a regional basis it becomes evident that the update of the BC refractive indices to Bond and Bergstrom (2006) significantly improves the previous underestimation of the aerosol absorption optical depth. In the global annual-mean, absorption acts to reduce the short-wave anthropogenic aerosol top-of-atmosphere (TOA) radiative forcing clear-sky from -0.79 to -0.53 W m-2 (33%) and all-sky from -0.47 to -0.13 W m-2 (72%). Our results confirm that basic assumptions about the BC refractive index play a key role for aerosol absorption and radiative forcing. The effect of the usage of more accurate effective medium approximations is comparably small. We demonstrate that the diversity in the AeroCom land-surface albedo fields contributes to the uncertainty in the simulated anthropogenic aerosol radiative forcings: the usage of an upper versus lower bound of the AeroCom land albedos introduces a global annual-mean TOA forcing range of 0.19 W m-2 (36%) clear-sky and of 0.12 W m-2 (92%) all-sky. The consideration of black carbon inclusions on cloud radiative properties results in a small global annual-mean all-sky absorption of 0.05 W m-2 and a positive TOA forcing perturbation of 0.02 W m-2. The long-wave aerosol radiative effects are small for anthropogenic aerosols but become of relevance for the larger natural dust and sea-salt aerosols.

Stier, P.; Seinfeld, J. H.; Kinne, S.; Boucher, O.

2007-05-01

423

Sound propagation and force chains in granular materials  

NASA Astrophysics Data System (ADS)

Granular materials are inherently heterogeneous, leading to challenges in formulating accurate models of sound propagation. In order to quantify acoustic responses in space and time, we perform experiments in a photoelastic granular material in which the internal stress pattern (in the form of force chains) is visible. We utilize two complementary methods, high-speed imaging and piezoelectric transduction, to provide particle-scale measurements of both the amplitude and speed of an acoustic wave in the near-field regime. We observe that the wave amplitude is on average largest within particles experiencing the largest forces, particularly in those chains radiating away from the source, with the force-dependence of this amplitude in qualitative agreement with a simple Hertzian-like model of particle contact area. In addition, we are able to directly observe rare transiently strong force chains formed by the opening and closing of contacts during propagation. The speed of the leading edge of the pulse is in agreement with the speed of a one-dimensional chain, while the slower speed of the peak response suggests that it contains waves which have travelled over multiple paths even within just this near-field region. These effects highlight the importance of particle-scale behaviors in determining the acoustical properties of granular materials.

Owens, E. T.; Daniels, K. E.

2011-06-01

424

Bending forces plastically deform growing bacterial cell walls  

E-print Network

Cell walls define a cell shape in bacteria. They are rigid to resist large internal pressures, but remarkably plastic to adapt to a wide range of external forces and geometric constraints. Currently, it is unknown how bacteria maintain their shape. In this work, we develop experimental and theoretical approaches and show that mechanical stresses regulate bacterial cell-wall growth. By applying a precisely controllable hydrodynamic force to growing rod-shaped Escherichia coli and Bacillus subtilis cells, we demonstrate that the cells can exhibit two fundamentally different modes of deformation. The cells behave like elastic rods when subjected to transient forces, but deform plastically when significant cell wall synthesis occurs while the force is applied. The deformed cells always recover their shape. The experimental results are in quantitative agreement with the predictions of the theory of dislocation-mediated growth. In particular, we find that a single dimensionless parameter, which depends on a combination of independently measured physical properties of the cell, can describe the cell's responses under various experimental conditions. These findings provide insight into how living cells robustly maintain their shape under varying physical environments.

Ariel Amir; Farinaz Babaeipour; Dustin B. McIntosh; David R. Nelson; Suckjoon Jun

2014-04-30

425

Bending forces plastically deform growing bacterial cell walls  

PubMed Central

Cell walls define a cells shape in bacteria. The walls are rigid to resist large internal pressures, but remarkably plastic to adapt to a wide range of external forces and geometric constraints. Currently, it is unknown how bacteria maintain their shape. In this paper, we develop experimental and theoretical approaches and show that mechanical stresses regulate bacterial cell wall growth. By applying a precisely controllable hydrodynamic force to growing rod-shaped Escherichia coli and Bacillus subtilis cells, we demonstrate that the cells can exhibit two fundamentally different modes of deformation. The cells behave like elastic rods when subjected to transient forces, but deform plastically when significant cell wall synthesis occurs while the force is applied. The deformed cells always recover their shape. The experimental results are in quantitative agreement with the predictions of the theory of dislocation-mediated growth. In particular, we find that a single dimensionless parameter, which depends on a combination of independently measured physical properties of the cell, can describe the cells responses under various experimental conditions. These findings provide insight into how living cells robustly maintain their shape under varying physical environments. PMID:24711421

Amir, Ariel; Babaeipour, Farinaz; McIntosh, Dustin B.; Nelson, David R.; Jun, Suckjoon

2014-01-01

426

Evaluation of the XSENS Force Shoe on ISS  

NASA Technical Reports Server (NTRS)

The Advanced Resistive Exercise Device (ARED) offers crewmembers a wide range of resistance exercises but does not provide any type of load monitoring; any load data received are based on crew self-report of dialed in load. This lack of real-time ARED load monitoring severely limits research analysis. To address this issue, portable load monitoring technologies are being evaluated to act as a surrogate to ARED's failed instrumentation. The XSENS ForceShoe"TM" is a commercial portable load monitoring tool, and performed well in ground tests. The ForceShoe "TM" was recently deployed on the International Space Station (ISS), and is being evaluated as a tool to monitor ARED loads.

Hanson, A. M.; Peters, B. T.; Newby, N.; Ploutz-Snyder, L

2014-01-01

427

Ohmic-heating solenoid design utilizing forced-cooled windings  

SciTech Connect

This paper discusses the feasibility of using NbTi internally cooled cable superconductor (ICCS) in the ohmic-heating central solenoid for the fusion engineering device (FED). The ICCS conductor provides cryostable operation with liberal stability margin. The forced cooled concept has a high winding current density which reduces the size and the cost of the device. The forced-cooled concept requires complex helium manifolding, but a unique approach has been developed to solve the problem. The conductor design, the winding design, and the performance analyses are described. The solenoid is designed to operate at 8-T peak field and provides 60 MAT. The operating current for the solenoid is 21.3 kA, which is 60% of the critical current at 8 T.

Srivastava, V.C.

1983-01-01

428

Radation force on a relativistic plasma and the Eddington limit  

SciTech Connect

The Thomson-scattering radiation force on a hot isotropic exceeds that on a cold one by a factor of (2/3<(..gamma beta..)/sup 2/>+1), where ..gamma.. = (1-..beta../sup 2/)/sup -1/2/ is the electron Lorentz factor. This excess force results from the anisotropic loss of internal energy. Consequently, a relativistic plasma with <..gamma../sup 2/>>>5/2, when exposed to an anisotropic radiation field, acts as a rocket-a ''Compton rocket'', Compton rockets quite likely play a role in the more exotic astronomical objects (quasars, blazars, Seyfert nuclei, compact galactic X-ray sources, etc.), which appear to operate within a few orders of magnitude of the (classical) Thomson-scattering Eddington limit.

O'Dell, S.L.

1981-02-01

429

Search for a new force  

SciTech Connect

Horizontal motions of a well-balanced hollow copper sphere floating and almost totally submerged in a well insulated and shielded tank filled with water at 4/sup 0/C were measured in the vicinity of a large cliff. A motion was observed in a direction nearly perpendicular to, and directed away from, the face of the cliff. Conventional explanations for this effect have not been found. The observation is consistent with the existence of a weak, non-Newtonian, substance dependent, medium range force of a magnitude compatible with results deduced from gravity measurements as a function of depth in mines and with conclusions reached in a recent reanalysis of the Eoetvoes experiment. Further measurements with different elements and in different geometries will be required to establish definitely the existence, source, and description of such a new force.

Thieberger, P.

1987-01-01

430

Slope effect on pushing forces.  

PubMed

In some occupations pushing forces are frequent when performed on horizontal ground and are standardized (ISO 2002). In special cases employees are obliged to grow container on slopes and the strains are poorly investigated. The objective of this work is to measure forces required to push garbage container on horizontal and inclined at 0, 4, 11 and 16 % grounds. Sudden and significant increases in heart rate reflect the possible risk of heart overload in long displacements. This study proposes realistic limits and provides a simple and protective tool for a group of employees without distinction of age or gender. These limits can even be reduced to a quasi-linear model where push 200 kg is the maximum for 0% slope and 60 kg for 10% slope. PMID:22317600

Turpin-Legendre, E; Meyer, J P

2012-01-01

431

Munich International Summer University  

E-print Network

Munich International Summer University Summer 2011 #12;MISU® ANNUAL REPORT 2011 #12;#12;MISU- nich International Summer University. MISU® is an excellent opportunity for international students International Summer University, or MISU®, giving a distinct vision and common standards to the various programs

Gerkmann, Ralf

432

International Summer School2014  

E-print Network

International Summer School2014 #12;#12;Contents About Dalian University of Technology 3 About International Summer Camp 11 Session 3 Intensive Training on Chinese Language 15 About Dalian 19 #12;#12;About for International Students Education". The non-degree seeking programs at DUT include International Summer School

Haviland, David

433

international summer school 2012  

E-print Network

international summer school 2012 studenthandbook #12;international summer school 2012 Class of 2012 international summer school 2012 Welcome to the University of Exeter We are delighted that you have won a place on the International summer school for 2012. studenthandbook We are proud of our position as a top 10 university

Mumby, Peter J.

434

Assessor Training International  

E-print Network

NVLAP Assessor Training International Arrangements #12;Assessor Training 2009: International;Assessor Training 2009: International Arrangements 3 2009 is the 10th anniversary of the signing granted by a signatory to the ILAC Arrangement #12;Assessor Training 2009: International Arrangements 4

435

Physics of Forced Unsteady Separation  

NASA Technical Reports Server (NTRS)

This report contains the proceedings of a workshop held at NASA Ames Research Center in April 1990. This workshop was jointly organized by NASA, the Air Force Office of Scientific Research (AFOSR), and the Army Research Office (ARO), and was directed toward improved understanding of the physical processes that cause unsteady separation to occur. The proceedings contain the written contributions for the workshop, and include selected viewgraphs used in the various presentations.

Carr, Lawrence W. (editor)

1992-01-01

436

Mechanical Forces Governing Tissue Dynamics  

NASA Astrophysics Data System (ADS)

We have refined a UV-laser microbeam to investigate the forces at play during morphogenesis, i.e. early biological development, in the fruit fly Drosophila (1). While the microbeam typically is used to ablate tissue with cellular spatial resolution, it has the capability for submicron and thus subcellular spatial resolution. The microbeam can be steered in two-dimensions and UV-laser dissection occurred in vivo while the tissue was imaged in real time using a (visible) laser-scanning confocal microscope. We investigated a morphogenic process, known as dorsal closure, in a genetically engineered strain of Drosophila where green fluorescent protein has been fused to a fragment of a native structural protein (2). This allowed us to visualize the fluorescing contours of two opposing, outer sheets of tissue closing over an inner tissue sheet. Time-lapse imaging captured the contours in native closure as well as in response to UV-laser dissection. Specific patterns of dissection essentially eliminated a selected force: by tracking the changes in contour geometry we estimated the relative magnitude of that force (mechanical jump). Using this approach we identified and characterized a set of forces governing tissue dynamics. We have developed a mechanical model for the dynamics of dorsal closure based on this data set. This model provides a theoretical framework for investigating defective closure in mutant flies. Dorsal closure is a model system for various aspects of cell movement in wound healing and vertebrate development. This research has been supported by the DoD MFEL Program as administered by the AFOSR and by the NIH. 1. M.S. Hutson, Y. Tokutake, M-S. Chang, J.W. Bloor, S. Venakides, D.P. Kiehart, and G.S. Edwards. "Laser dissection of morphogenetic dynamics in Drosophila dorsal closure." In preparation. 2. D.P. Kiehart, et al, J. Cell Biol. 149, 471 (2000).

Edwards, Glenn

2002-10-01

437

Gravitational Forces on the Branes  

Microsoft Academic Search

We examine the gravitational forces in a brane-world scenario felt by point particles on two 3-branes bounding a 5-dimensional AdS space with S1\\/Z2 symmetry. The particles are treated as perturbations on the vacuum metric and coordinate conditions are chosen so that no brane bending effects occur. We make an ADM type decomposition of the metric tensor and solve Einstein's equations

R. Arnowitt; J. Dent

2005-01-01

438

Gravitational Forces on the Branes  

Microsoft Academic Search

We examine the gravitational forces in a brane-world scenario felt by point particles on two 3-branes bounding a 5-dimensional AdS space with S1\\/Z2 symmetry. The particles are treated as perturbations on the vacuum metric and coordinate conditions are chosen so that no brane bending effects occur. We make an ADM type decomposition of the metric tensor and solve Einstein's equations

R. Arnowitt; J. Dent

2004-01-01

439

Prediction of vehicle impact forces  

E-print Network

1990 ABSTRACT Prediction of Vehicle Impact Forces. (May 1990) Darrell Laine Kaderka, B. S. Texas A&M University Chair of Advisory Committee: Dr, C, E. Buth Design loads for bridge rails are difficult to determine. Vehicle geometric properties... and impact conditions are just two variables that present difficulties to engineers attempting to calculate these loads. Research has been performed by several organizations in attempts to increase knowledge about loading conditions for bridge rails...

Kaderka, Darrell Laine

1990-01-01

440

Micromachined piconewton force sensor for biophysics investigations  

SciTech Connect

We describe a micromachined force sensor that is able to measure forces as small as 1 pN in both air and water. First, we measured the force field produced by an electromagnet on individual 2.8 {mu}m magnetic beads glued to the sensor. By repeating with 11 different beads, we measured a 9% standard deviation in saturation magnetization. We next demonstrated that the sensor was fully functional when immersed in physiological buffer. These results show that the force sensors can be useful for magnetic force calibration and also for measurement of biophysical forces on chip.

Koch, Steven J.; Thayer, Gayle E.; Corwin, Alex D.; Boer, Maarten P. de [Sandia National Laboratories, Albuquerque, New Mexico 87185 (United States)

2006-10-23

441

Friction forces in cosmological models  

E-print Network

We investigate the dynamics of test particles undergoing friction forces in a Friedmann-Robertson-Walker (FRW) spacetime. The interaction with the background fluid is modeled by introducing a Poynting-Robertson-like friction force in the equations of motion, leading to measurable (at least in principle) deviations of the particle trajectories from geodesic motion. The effect on the peculiar velocities of the particles is investigated for various equations of state of the background fluid and different standard cosmological models. The friction force is found to have major effects on particle motion in closed FRW universes, where it turns the time-asymptotic value (approaching the recollapse) of the peculiar particle velocity from ultra-relativistic (close to light speed) to a co-moving one, i.e., zero peculiar speed. On the other hand, for open or flat universes the effect of the friction is not so significant, because the time-asymptotic peculiar particle speed is largely non-relativistic also in the geodesic case.

Donato Bini; Andrea Geralico; Daniele Gregoris; Sauro Succi

2014-08-23

442

Nongravitational forces and meteoroid streams  

NASA Astrophysics Data System (ADS)

The action of the solar electromagnetic radiation on the moving interplanetary dust particles in its more complete form than the special case known as the Poynting-Robertson effect (P-R effect) is theoretically discussed in application to meteoroid stream of comet Encke. Normal and transverse components of the perturbing nongravitational force are used due to the action of the solar electromagnetic radiation. It is shown that the normal component of the force is negligible. However, the transverse component is very important: it can probably completely explain all the observed meteoroid streams situated along the orbit of comet Encke (and, possibly, some asteroids) as the product of the comet Encke alone. Much shorter time is required for producing such a meteoroid stream than is a general conception. If the idea about the significance of the transverse component of the nongravitational force (may be, not produced by electromagnetic radiation) is correct, it may have important consequences for our understanding of aging of comets, global evolution of the cometary (and, partially, asteroidal) system, and, of course, for a long-term evolution of small interplanetary particles.

Klacka, Jozef

1994-05-01

443

Nanorheology by atomic force microscopy  

NASA Astrophysics Data System (ADS)

We present an Atomic Force Microscopy (AFM) based method to investigate the rheological properties of liquids confined within a nanosize gap formed by an AFM tip apex and a solid substrate. In this method, a conventional AFM cantilever is sheared parallel to a substrate surface by means of a lock-in amplifier while it is approaching and retracting from the substrate in liquid. The normal solvation forces and lateral viscoelastic shear forces experienced by the AFM tip in liquid can be simultaneously measured as a function of the tip-substrate distance with sub-nanometer vertical resolution. A new calibration method is applied to compensate for the linear drift of the piezo transducer and substrate system, leading to a more precise determination of the tip-substrate distance. By monitoring the phase lag between the driving signal and the cantilever response in liquid, the frequency dependent viscoelastic properties of the confined liquid can also be derived. Finally, we discuss the results obtained with this technique from different liquid-solid interfaces. Namely, octamethylcyclotetrasiloxane and water on mica and highly oriented pyrolytic graphite.

Li, Tai-De; Chiu, Hsiang-Chih; Ortiz-Young, Deborah; Riedo, Elisa

2014-12-01

444

Nanorheology by atomic force microscopy.  

PubMed

We present an Atomic Force Microscopy (AFM) based method to investigate the rheological properties of liquids confined within a nanosize gap formed by an AFM tip apex and a solid substrate. In this method, a conventional AFM cantilever is sheared parallel to a substrate surface by means of a lock-in amplifier while it is approaching and retracting from the substrate in liquid. The normal solvation forces and lateral viscoelastic shear forces experienced by the AFM tip in liquid can be simultaneously measured as a function of the tip-substrate distance with sub-nanometer vertical resolution. A new calibration method is applied to compensate for the linear drift of the piezo transducer and substrate system, leading to a more precise determination of the tip-substrate distance. By monitoring the phase lag between the driving signal and the cantilever response in liquid, the frequency dependent viscoelastic properties of the confined liquid can also be derived. Finally, we discuss the results obtained with this technique from different liquid-solid interfaces. Namely, octamethylcyclotetrasiloxane and water on mica and highly oriented pyrolytic graphite. PMID:25554301

Li, Tai-De; Chiu, Hsiang-Chih; Ortiz-Young, Deborah; Riedo, Elisa

2014-12-01

445

A six-component force/moment sensor calibration stand  

NASA Astrophysics Data System (ADS)

A compact portable stand for calibration of multicomponent internal balances is described. The stand is designed to control/eliminate misalignments between load trains and the balance being calibrated; it generates forces and moments with pneumatic cylinders for all but rolling moment, which is applied with conventional weights. Load application control is discussed, and performance is analyzed. It is noted that the calibration stand has the ability to sense off-axis loads resulting from distortion/deflections due to the primary loading. Having sensed these off-axis loads, the system can be adjusted to minimize or eliminate them while retaining correct alignment of the primary load with the balance.

Estlow, Edward G. W.; Kovacevic, Nebojsa

1990-06-01

446

Point Charge Forces in 1D Model  

NSDL National Science Digital Library

The Point Charge Forces in One-Dimension model investigates the electric force that one charged particle exerts on another. The electric force is shown in three ways. First, particle 2 can be dragged left or right to sample the force at various locations - the force on each particle is shown with an arrow. Second, the numerical value of each force is shown in the table at the bottom. Third, you can check the box at the top of the menu to plot a graph of the electric force as a function of position. For the graph (and the numerical values), we define positive force as a force pointing to the right, and negative force as a force pointing to the left. The Point Charge Forces in One-Dimension was created using the Easy Java Simulations (EJS) modeling tool. It is distributed as a ready-to-run (compiled) Java archive. Double clicking the ejs_bu_Point_Charge_Force_1D.jar file will run the program if Java is installed.

Duffy, Andrew

2010-04-16

447

Kelvin probe force microscopy in liquid using electrochemical force microscopy  

PubMed Central

Summary Conventional closed loop-Kelvin probe force microscopy (KPFM) has emerged as a powerful technique for probing electric and transport phenomena at the solidgas interface. The extension of KPFM capabilities to probe electrostatic and electrochemical phenomena at the solidliquid interface is of interest for a broad range of applications from energy storage to biological systems. However, the operation of KPFM implicitly relies on the presence of a linear lossless dielectric in the probesample gap, a condition which is violated for ionically-active liquids (e.g., when diffuse charge dynamics are present). Here, electrostatic and electrochemical measurements are demonstrated in ionically-active (polar isopropanol, milli-Q water and aqueous NaCl) and ionically-inactive (non-polar decane) liquids by electrochemical force microscopy (EcFM), a multidimensional (i.e., bias- and time-resolved) spectroscopy method. In the absence of mobile charges (ambient and non-polar liquids), KPFM and EcFM are both feasible, yielding comparable contact potential difference (CPD) values. In ionically-active liquids, KPFM is not possible and EcFM can be used to measure the dynamic CPD and a rich spectrum of information pertaining to charge screening, ion diffusion, and electrochemical processes (e.g., Faradaic reactions). EcFM measurements conducted in isopropanol and milli-Q water over Au and highly ordered pyrolytic graphite electrodes demonstrate both sample- and solvent-dependent features. Finally, the feasibility of using EcFM as a local force-based mapping technique of material-dependent electrostatic and electrochemical response is investigated. The resultant high dimensional dataset is visualized using a purely statistical approach that does not require a priori physical models, allowing for qualitative mapping of electrostatic and electrochemical material properties at the solidliquid interface.

Collins, Liam; Jesse, Stephen; Kilpatrick, Jason I; Tselev, Alexander; Okatan, M Baris; Kalinin, Sergei V

2015-01-01

448

Kelvin probe force microscopy in liquid using electrochemical force microscopy.  

PubMed

Conventional closed loop-Kelvin probe force microscopy (KPFM) has emerged as a powerful technique for probing electric and transport phenomena at the solid-gas interface. The extension of KPFM capabilities to probe electrostatic and electrochemical phenomena at the solid-liquid interface is of interest for a broad range of applications from energy storage to biological systems. However, the operation of KPFM implicitly relies on the presence of a linear lossless dielectric in the probe-sample gap, a condition which is violated for ionically-active liquids (e.g., when diffuse charge dynamics are present). Here, electrostatic and electrochemical measurements are demonstrated in ionically-active (polar isopropanol, milli-Q water and aqueous NaCl) and ionically-inactive (non-polar decane) liquids by electrochemical force microscopy (EcFM), a multidimensional (i.e., bias- and time-resolved) spectroscopy method. In the absence of mobile charges (ambient and non-polar liquids), KPFM and EcFM are both feasible, yielding comparable contact potential difference (CPD) values. In ionically-active liquids, KPFM is not possible and EcFM can be used to measure the dynamic CPD and a rich spectrum of information pertaining to charge screening, ion diffusion, and electrochemical processes (e.g., Faradaic reactions). EcFM measurements conducted in isopropanol and milli-Q water over Au and highly ordered pyrolytic graphite electrodes demonstrate both sample- and solvent-dependent features. Finally, the feasibility of using EcFM as a local force-based mapping technique of material-dependent electrostatic and electrochemical response is investigated. The resultant high dimensional dataset is visualized using a purely statistical approach that does not require a priori physical models, allowing for qualitative mapping of electrostatic and electrochemical material properties at the solid-liquid interface. PMID:25671164

Collins, Liam; Jesse, Stephen; Kilpatrick, Jason I; Tselev, Alexander; Okatan, M Baris; Kalinin, Sergei V; Rodriguez, Brian J

2015-01-01

449

Discriminating short-range from van der Waals forces using total force data in noncontact atomic force microscopy  

NASA Astrophysics Data System (ADS)

Noncontact atomic force microscopy (NC-AFM) features the measurement of forces with highest spatial resolution and sensitivity, resolving forces of the order of pico-Newtons with submolecular resolution. However, the measured total force is a mixture composed of various interactions. While some interactions such as electrostatic or magnetic forces can be excluded by a careful design of the experiment, the subtraction of van der Waals forces, which mainly originate from London dispersion interactions between the macroscopic tip shank and the bulk sample, remains a challenge. We present the determination of the inherently present van der Waals forces in total interaction force data from fitting a suitable model, allowing for extraction of the short-range force component. We compare the applicability of several van der Waals models based on experimental interaction data from the calcite(1014) surface. The feasibility to fit these models to experimental data is critically discussed. We furthermore introduce criteria to assess the transition point from pure long-range interaction to mixed short- and long-range forces based on the variance of lateral and vertical force data. This determination allows us to extract the short-range interaction forces, which remained a challenge so far in NC-AFM experiments.

Kuhn, Stefan; Rahe, Philipp

2014-06-01

450

Frequency domain multiplexing of force signals with application to magnetic resonance force microscopy  

E-print Network

Frequency domain multiplexing, using an actively damped micromechanical cantilever, is used to detect multiple force signals simultaneously. The measurement principle is applied to magnetic resonance force microscopy to ...

Degen, Christian

451

The puzzling reliability of the Force Concept Inventory  

NASA Astrophysics Data System (ADS)

The Force Concept Inventory (FCI) has influenced the development of many research-based pedagogies. However, no data exists on the FCI's internal consistency or test-retest reliability. The FCI was administered twice to one hundred students during the first week of classes in an electricity and magnetism course with no review of mechanics between test administrations. High Kuder-Richardson reliability coefficient values, which estimate the average correlation of scores obtained on all possible halves of the test, suggest strong internal consistency. However, 31% of the responses changed from test to retest, suggesting weak reliability for individual questions. A chi-square analysis shows that change in responses was neither consistent nor completely random. The puzzling conclusion is that although individual FCI responses are not reliable, the FCI total score is highly reliable.

Lasry, Nathaniel; Rosenfield, Steven; Dedic, Helena; Dahan, Ariel; Reshef, Orad

2011-09-01

452

Dynamic Force Measurement with Strain Gauges  

ERIC Educational Resources Information Center

Discusses the use of four strain gauges, a Wheatstone bridge, and an oscilloscope to measure forces dynamically. Included is an example of determining the centripetal force of a pendulum in a general physics laboratory. (CC)

Lee, Bruce E.

1974-01-01

453

The Fourth Force in Nature. Part I  

ERIC Educational Resources Information Center

The properties of the weak force between the subatomic particles is described. The weak force is observed in the form of nuclear beta radioactivity. Applications are given to terrestrial and extraterrestrial phenomena. (TS)

Marshak, R. E.

1971-01-01

454

Push Me, Pull Me with Force  

NSDL National Science Digital Library

In this lesson, students use a magnet to demonstrate that force leads to motion. Students will recognize forces that attract and repel other objects and demonstrate them. Students will also describe various types of motions.

Pennsylvania Department of Education

2012-03-02

455

A Simple Apparatus for Electrostatic Force Measurement.  

ERIC Educational Resources Information Center

Describes the construction of an apparatus that demonstrates that electrostatic forces can be large and also gives some idea of dependence of electrostatic forces between charged parallel discs on potential differences and separation. (CS)

Hale, D. P.

1981-01-01

456

Development of a light force accelerometer  

E-print Network

In this work, the feasibility of a light force accelerometer was experimentally demonstrated. The light force accelerometer is an optical inertial sensor which uses focused laser light to levitate and trap glass microspheres ...

Butts, David LaGrange

2008-01-01

457

Modeling basin-scale internal waves in a stratified lake  

Microsoft Academic Search

Basin-scale internal waves provide the driving forces for vertical and horizontal fluxes in a stratified lake below the wind-mixed layer. Thus, correct modeling of lake mixing and transport requires accurate modeling of basin- scale internal waves: examining this capability with a hydrostatic, z-coordinate three-dimensional (3D) numerical model at coarse grid resolutions is the focus of this paper. It is demonstrated

Ben R. Hodges; Jrg Imberger; Angelo Saggio; K. B. Winters

2000-01-01

458

Internal tides and waves near the continental shelf edge  

Microsoft Academic Search

The subject is reviewed from the viewpoints of theory, internal tide and wave structure and their implications.A wider theoretical context suggests scope for further investigation of natural or nearly-trapped forms above the inertial frequency.Although internal tides in many locations are observed to have first-mode vertical structure, higher modes are seen offshore from shallow shelf-break forcing and for particular Froude numbers,

J. M. Huthnance

1989-01-01

459

SUDAN: ANATOMY OF A CONFLICT Escalation: SAF and SPLA Force Deployment Within and Around Abyei  

E-print Network

SUDAN: ANATOMY OF A CONFLICT Chapter I Escalation: SAF and SPLA Force Deployment Within and Around Abyei Mid-2010 to January 2011 1 Harvard Humanitarian Initiative Sudan: Anatomy of a Conflict Executive in Sudan Since January 2011, humanitarian actors and international observers, including United Nations

Chou, James

460

Bone contact forces on the distal tibia during the stance phase of running  

Microsoft Academic Search

Although the tibia is a common site of stress fractures in runners, the loading of the tibia during running is not well understood. An integrated experimental and modeling approach was therefore used to estimate the bone contact forces acting on the distal end of the tibia during the stance phase of running, and the contributions of external and internal sources

Siriporn Sasimontonkul; Brian K. Bay; Michael J. Pavol

2007-01-01

461

Behavior of precipitating water drops under the influence of electrical and aerodynamical forces  

Microsoft Academic Search

The present work performs a realistic modeling of precipitating charged water drops under the influence of electrical and dynamical forces in the vertical and downward electric field of a thundercloud. The following factors which control the shape of an individual raindrop are taken into account: surface tension, internal hydrostatic pressure, aerodynamic pressure, and electrostatic pressure. Unlike a recent and notable

Sylvain Coquillat; Serge Chauzy

1993-01-01

462

Method and system for measuring gate valve clearances and seating force  

DOEpatents

Valve clearances and seating force, as well as other valve operational parameters, are determined by measuring valve stem rotation during opening and closing operations of a translatable gate valve. The magnitude of the stem rotation, and the relative difference between the stem rotation on opening and closing provides valuable data on the valve internals in a non-intrusive manner.

Casada, Donald A. (Knoxville, TN); Haynes, Howard D. (Knoxville, TN); Moyers, John C. (Oak Ridge, TN); Stewart, Brian K. (Burns, TN)

1996-01-01

463

Geometric quantum gate for trapped ions based on optical dipole forces induced by Gaussian laser beams  

SciTech Connect

We propose an implementation of quantum logic gates via internal state dependent displacements of ions in a linear Paul trap caused by optical dipole forces. Based on a general quantum analysis of the system dynamics we consider specific implementations with alkaline-earth-metal ions. For experimentally realistic parameters gate infidelities as low as 10{sup -4} can be obtained.

Staanum, Peter; Drewsen, Michael; Moelmer, Klaus [QUANTOP-Danish National Research Foundation Center for Quantum Optics, Department of Physics and Astronomy, University of Aarhus, DK-8000 Aarhus C (Denmark)

2004-11-01

464

Task Force Report. State of the Art of Adult Education: CONFINTEA Follow Up. [and] Workshop Reports.  

ERIC Educational Resources Information Center

Includes task force recommendations on the role of the International Council for Adult Education in monitoring achievement of adult education objectives, qualitative and quantitative indicators, and diverse data collection methods. Eleven workshop reports discuss progress on adult education policy advocacy, documentation, health care reform,

Convergence, 2001

2001-01-01

465

Method and system for measuring gate valve clearances and seating force  

DOEpatents

Valve clearances and seating force, as well as other valve operational parameters, are determined by measuring valve stem rotation during opening and closing operations of a translatable gate valve. The magnitude of the stem rotation, and the relative difference between the stem rotation on opening and closing provides valuable data on the valve internals in a non-intrusive manner. 8 figs.

Casada, D.A.; Haynes, H.D.; Moyers, J.C.; Stewart, B.K.

1996-01-30

466

Reduction in Work Force Classified Civil Service Staff Office of Human Resources  

E-print Network

Reduction in Work Force ­ Classified Civil Service Staff 9.20 Office of Human Resources Applies to internally by the Health System. Health System employees should contact their human resource department Definition Health System Includes Dodd Hall, James Cancer Hospital and Solove Research Institute, OSU

Howat, Ian M.

467

Force Control of an Intelligent Armwrestling System  

Microsoft Academic Search

An intelligent arm-wrestling system recently developed in our laboratory is comprised of an arm-force generation mechanism and a control system that detects the maximum arm-force of a user in the early stage of the match, generates a different game scenario each time, and executes force feedback control to implement the scenario. This paper presents a mathematical modeling of the force

Chul-Goo Kang; Ik-Xu Son; Han-Sung Lee; Ho-Yeon Kim

2006-01-01

468

Down force calibration stand test report  

SciTech Connect

The Down Force Calibration Stand was developed to provide an improved means of calibrating equipment used to apply, display and record Core Sample Truck (CST) down force. Originally, four springs were used in parallel to provide a system of resistance that allowed increasing force over increasing displacement. This spring system, though originally deemed adequate, was eventually found to be unstable laterally. For this reason, it was determined that a new method for resisting down force was needed.

BOGER, R.M.

1999-08-13

469

Genetically encoded force sensors for measuring mechanical forces in proteins  

PubMed Central

There are three sources of free energy for cells: chemical potential, electrical potential and mechanical potential. There is little known about the last one since there have not been simple ways to measure stress in proteins in cells. we have now developed genetically encoded force sensors to assess the stress in fibrous proteins in living cells. These FReT based fluorescence sensors can be read out at video rates and provide real time maps of the stress distribution in cells, tissues and animals. The sensors can be inserted into specific proteins and in general do not disturb the normal function or anatomy. The original sensors used mutant GFPs linked by elastic linkers. These sensors provide a linear output with applied stress but the response is linear in strain. To improve contrast and dynamic range we have now developed a new class of sensors that are smaller making them less invasive, and have much higher intrinsic sensitivity since force modulates the angle between the donor and acceptor much more than the distance between them. Known as cpstFRET, the probe shows improved biocompatibility, wider dynamic range and higher sensitivity. PMID:21966553

Wang, Yuexiu; Sachs, Frederick

2011-01-01

470

Continental Shelf Research 20 (2000) 1}13 Internal tide e!ects on a sewage plume  

E-print Network

Continental Shelf Research 20 (2000) 1}13 Internal tide e!ects on a sewage plume at Sand Island, is described and explained by the forcing from an internal tide. The sewage plume, discharged from the Sand to the di!user, suggested that the presence of an internal tide of 18 km wavelength propagating along

Fabrikant, Sara Irina

471

76 FR 45311 - International Joint Commission Public Hearings on Binational Management of Lake of the Woods and...  

Federal Register 2010, 2011, 2012, 2013

...on Binational Management of Lake of the Woods and Rainy River Watershed The International...report of its International Lake of the Woods and Rainy River Watershed Task Force...issues in the international Lake of the Woods and Rainy River watershed. Task...

2011-07-28

472

The Common Forces: Conservative or Nonconservative?  

ERIC Educational Resources Information Center

Of the forces commonly encountered when solving problems in Newtonian mechanics, introductory texts usually limit illustrations of the definitions of conservative and nonconservative forces to gravity, spring forces, kinetic friction and fluid resistance. However, at the expense of very little class time, the question of whether each of the common

Keeports, David

2006-01-01

473

Precipitation response to regional radiative forcing  

NASA Astrophysics Data System (ADS)

Precipitation shifts can have large impacts on human society and ecosystems. Many aspects of how inhomogeneous radiative forcings influence precipitation remain unclear, however. Here we investigate regional precipitation responses to various forcings imposed in different latitude bands in a climate model. We find that several regions show strong, significant responses to most forcings, but the magnitude and even the sign depends upon the forcing location and type. Aerosol and ozone forcings typically induce larger responses than equivalent carbon dioxide (CO2) forcing, and the influence of remote forcings often outweighs that of local forcings. Consistent with this, ozone and especially aerosols contribute greatly to precipitation changes over the Sahel and South and East Asia in historical simulations, and inclusion of aerosols greatly increases the agreement with observed trends in these areas, which cannot be attributed to either greenhouse gases or natural forcings. Estimates of precipitation responses derived from multiplying our Regional Precipitation Potential (RPP; the response per unit forcing relationships) by historical forcings typically capture the actual response in full transient climate simulations fairly well, suggesting that these relationships may provide useful metrics. The strong sensitivity to aerosol and ozone forcing suggests that although some air quality improvements may unmask greenhouse gas-induced changes in temperature, they have large benefits for reducing regional disruption of the hydrologic cycle.

Shindell, D. T.; Voulgarakis, A.; Faluvegi, G.; Milly, G.

2012-02-01

474

Drag force in asymptotically Lifshitz spacetimes  

E-print Network

We calculated drag force for asymptotically Lifshitz space times in (d + 2)-dimensions with arbitrary dynamical exponent $z$. We find that at zero and finite temperature the drag force has a non-zero value. Using the drag force calculations, we investigate the DC conductivity of strange metals.

Kazem Bitaghsir Fadafan

2010-09-13

475

FORCING AXIOMS AND THE CONTINUUM HYPOTHESIS  

E-print Network

FORCING AXIOMS AND THE CONTINUUM HYPOTHESIS DAVID known as a forcing axiom _ is consistent. The first and best known example is Martin's Axiom for @1 ]. This is the forcing axiom for compact spaces which do not contain uncountable families of pairwise disjoint open

Larson, Paul B.

476

Forces on laboratory model dredge cutterhead  

E-print Network

cutting force calculations are shown. Also, the effects of undercutting and overcutting are demonstrated in the figure. Figure 5: Description of forces on cutter when overcutting (Top) and undercutting (Bottom) (Miedema 1989) ?o ?1 11... Example of spud carriage cuttersuction dredge ......................................... 4 4 Two-dimensional cutting process ............................................................... 8 5 Description of forces on cutter when overcutting...

Young, Dustin Ray

2010-07-14

477

49 CFR 193.2067 - Wind forces.  

Code of Federal Regulations, 2013 CFR

...2013-10-01 2013-10-01 false Wind forces. 193.2067 Section 193.2067... Siting Requirements 193.2067 Wind forces. (a) LNG facilities must...integrity: (1) The direct effect of wind forces; (2) The pressure...

2013-10-01

478

49 CFR 193.2067 - Wind forces.  

Code of Federal Regulations, 2012 CFR

...2012-10-01 2012-10-01 false Wind forces. 193.2067 Section 193.2067... Siting Requirements 193.2067 Wind forces. (a) LNG facilities must...integrity: (1) The direct effect of wind forces; (2) The pressure...

2012-10-01

479

49 CFR 193.2067 - Wind forces.  

Code of Federal Regulations, 2011 CFR

...2011-10-01 2011-10-01 false Wind forces. 193.2067 Section 193.2067... Siting Requirements 193.2067 Wind forces. (a) LNG facilities must...integrity: (1) The direct effect of wind forces; (2) The pressure...

2011-10-01

480

FCS communications technology for the objective force  

Microsoft Academic Search

As part of its technology development program for the Army's Future Combat System (FCS), the Defense Advanced Research Projects Agency (DARPA) has been working to develop the enabling communications technology needed to revolutionize the Army's future land force into a network centric force capable of operation at a level of synchronization, mobility, and force effectiveness which has been heretofore unachievable.

Paul Sass; James A. Freebersyser

2002-01-01

481

Separation control at hydrofoils using Lorentz forces  

Microsoft Academic Search

Lorentz forces originating from surface-mounted actuators of permanent magnets and electrodes in weakly conducting fluids like seawater can be used to control flow separation at hydrofoils. The numerical results presented here are based on direct numerical simulation in the laminar flow regime, limited to Reynolds numbers of O(500). Control by steady forcing at the suction side and by oscillatory forcing

G. Mutschke; G. Gerbeth; T. Albrecht; R. Grundmann

2006-01-01

482

Electrostatic Force-Assisted Nanoimprint Lithography (EFAN)  

E-print Network

Electrostatic Force-Assisted Nanoimprint Lithography (EFAN) Xiaogan Liang,* Wei Zhang, Mingtao Li, electrostatic force-assisted nanoimprint lithography (EFAN), where a voltage applied between a mold and a substrate generates an electrostatic force that presses the mold into a resist on the substrate. We have

483

Sales-Force Incentives and Inventory Management  

Microsoft Academic Search

This article studies the problem of sales-force compensation by considering the impact of sales-force behavior on a firm's production and inventory system. The sales force's compensation package affects how the salespeople are going to exert their effort, which in turn determines the sales pattern for the firm's product and ultimately drives the performance of the firm's production and inventory system.

Fangruo Chen

2000-01-01

484

49 CFR 193.2067 - Wind forces.  

Code of Federal Regulations, 2010 CFR

...2010-10-01 2010-10-01 false Wind forces. 193.2067 Section 193.2067... Siting Requirements 193.2067 Wind forces. (a) LNG facilities must...integrity: (1) The direct effect of wind forces; (2) The pressure...

2010-10-01

485

Purdue extension Industry Analysis: The Five Forces  

E-print Network

Purdue extension EC-722 Industry Analysis: The Five Forces Cole Ehmke, Joan Fulton, and Jay Akridge,thebetterable you will be to respond. The forces affecting profitability are often beyond your control the profitability of an industry Outcome: Reader should understand the forces and be able to counter them

486

Clamping-Force Control for Electromechanical Brake  

Microsoft Academic Search

The estimation of the frictional and clamping forces is one of the key issues in the design and implementation of the electromechanical brake (EMB) system. In this paper, a clamping-force control algorithm is presented along with a consideration of the frictional characteristics and the estimation of the clamping force for a planetary reduction gear-type EMB. The frictional model is developed

Chihoon Jo; Sungho Hwang; Hyunsoo Kim

2010-01-01