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1

Internal forces during object manipulation  

PubMed Central

Internal force is a set of contact forces that does not disturb object equilibrium. The elements of the internal force vector cancel each other and, hence, do not contribute to the resultant (manipulation) force acting on the object. The mathematical independence of the internal and manipulation forces allows for their independent (decoupled) control realized in robotic manipulators. To examine whether in humans internal force is coupled with the manipulation force and what grasping strategy the performers utilize, the subjects (n=6) were instructed to make cyclic arm movements with a customized handle. Six combinations of handle orientation and movement direction were tested. These involved: parallel manipulations (1) VV task (vertical orientation and vertical movement) and (2) HH task (horizontal orientation and horizontal movement); orthogonal manipulations (3) VH task (vertical orientation and horizontal movement) and (4) HV task (horizontal orientation and vertical movement); and diagonal manipulations (5) DV task (diagonal orientation and vertical movement) and (6) DH task (diagonal orientation and horizontal movement). Handle weight (from 3.8 to 13.8 N), and movement frequency (from 1 to 3 Hz) were systematically changed. The analysis was performed at the thumb-virtual finger level (VF, an imaginary finger that produces a wrench equal to the sum of wrenches produced by all the fingers). At this level, the forces of interest could be reduced to the internal force and internal moment. During the parallel manipulations, the internal (grip) force was coupled with the manipulation force (producing object acceleration) and the thumb-VF forces increased or decreased in phase: the thumb and VF worked in synchrony to grasp the object more strongly or more weakly. During the orthogonal manipulations, the thumb-VF forces changed out of phase: the plots of the internal force vs. object acceleration resembled an inverted letter V. The HV task was the only task where the relative phase (coupling) between the normal forces of the thumb and VF depended on oscillation frequency. During the diagonal manipulations, the coupling was different in the DV and DH tasks. A novel observation of substantial internal moments is described: the moments produced by the normal finger forces were counterbalanced by the moments produced by the tangential forces such that the resultant moments were close to zero. Implications of the findings for the notion of grasping synergies are discussed. PMID:15912369

Gao, Fan; Latash, Mark L.; Zatsiorsky, Vladimir M.

2010-01-01

2

International Task Force on Volunteer Cleft Missions.  

PubMed

The International Task Force on Volunteer Cleft Missions was set up to provide a report to be presented at the Eighth International Congress of Cleft Palate and Associated Craniofacial Anomalies on September 12, 1997, in Singapore. The aim of the report was to provide data from a wide range of different international teams performing volunteer cleft missions and, thereafter, based on the collected data, to identify common goals and aims of such missions. Thirteen different groups actively participating in volunteer cleft missions worldwide were selected from the International Confederation of Plastic and Reconstructive Surgery's list of teams actively participating in volunteer cleft missions. Because of the time frame within which the committee had to work, three groups that did not respond by the stipulated deadline were omitted from the committee. The represented members and their respective institutions have undertaken more than 50 volunteer cleft missions to underdeveloped nations worldwide within the last 3 years. They have visited over 20 different countries, treating more than 3,500 patients worldwide. Based on the data collected and by consensus, the committee outlined recommendations for future volunteer cleft missions based on 1) mission objectives, 2) organization, 3) personal health and liability, 4) funding, 5) trainees in volunteer cleft missions, and 6) public relations. The task force believed that all volunteer cleft missions should have well-defined objectives, preferably with long-term plans. The task force also decided that it was impossible to achieve a successful mission without good organization and close coordination. All efforts should be made, and care taken, to ensure that there is minimal morbidity and no mortality. Finally, as ambassadors of goodwill and humanitarian aid, the participants must make every effort to understand and respect local customs and protocol. The main aims are to provide top-quality surgical service, train local doctors and staff, develop and nurture fledgling cleft programs, and, finally, make new friends. PMID:11886986

Yeow, Vincent K L; Lee, Seng-Teik T; Lambrecht, Thomas J; Barnett, John; Gorney, Mark; Hardjowasito, Widanto; Lemperle, Gottfried; McComb, Harold; Natsume, Nagato; Stranc, Mirek; Wilson, Libby

2002-01-01

3

Object motiondecoupled internal force control for a compliant multifingered hand  

E-print Network

Object motion­decoupled internal force control for a compliant multifingered hand Domenico degradation. This paper studies the structural conditions to design an internal force controller decoupled from object motions. The analysis is constructive and a controller of internal forces is proposed. We

Siena, Università di

4

Internal Force-Based Impedance Control for Cooperating Manipulators  

Microsoft Academic Search

Internal force-based impedance control for cooperat- ing manipulators controls the motion of the objects being manipulated and the internal force on the objects by enforcing a relationship between the velocity of each manipulator and the internal force on the manipulated objects. Each manipulator is directly given the properties of an impedance by the controller, thus, eliminating the need to have

Robert G. Bonitz; Tien C. Hsia

1993-01-01

5

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

6

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

Federal Register 2010, 2011, 2012, 2013, 2014

...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

7

Joining Forces: The Case of Alliant International University  

ERIC Educational Resources Information Center

Mergers and acquisitions are a prevalent force in higher education as more colleges and universities are joining forces to expand resources, enhance missions, or prevent closures. This study examines the merger of Alliant University (formerly California School of Professional Psychology) with United States International University to create what…

Leslie, Heather

2013-01-01

8

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

9

Locomotive and reptation motion induced by internal force and friction.  

PubMed

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-element model, we construct a model that 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. PMID:21797399

Sakaguchi, Hidetsugu; Ishihara, Taisuke

2011-06-01

10

Locomotive and reptation motion induced by internal force and friction  

NASA Astrophysics Data System (ADS)

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-element model, we construct a model that 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.

Sakaguchi, Hidetsugu; Ishihara, Taisuke

2011-06-01

11

Internal and external forces affecting management compensation.  

PubMed

Increasing media scrutiny, eventual implementation of health care reform, and proliferation of TQM/CQI programs are significantly affecting health care management compensation programs. Trustees are insisting that management pay be based on definitive performance standards and are becoming increasingly resistant to the annual increase that is no longer sacrosanct. Philosophical conflicts regarding compensation are developing between CEOs and boards. These external and internal factors will require managers to reassess their attitudes toward their own and subordinate's compensation. Managers, at all levels, will have to adjust to pay determination factors and practices that differ from those to which they have been accustomed. PMID:10130082

Browdy, J D

1993-12-01

12

On forced temperature changes, internal variability, and the AMO  

NASA Astrophysics Data System (ADS)

We 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

13

Permeability of continental crust influenced by internal and external forcing  

USGS Publications Warehouse

The permeability of continental crust is so highly variable that it is often considered to defy systematic characterization. However, despite this variability, some order has been gleaned from globally compiled data. What accounts for the apparent coherence of mean permeability in the continental crust (and permeability-depth relations) on a very large scale? Here we argue that large-scale crustal permeability adjusts to accommodate rates of internal and external forcing. In the deeper crust, internal forcing - fluxes induced by metamorphism, magmatism, and mantle degassing - is dominant, whereas in the shallow crust, external forcing - the vigor of the hydrologic cycle - is a primary control. Crustal petrologists have long recognized the likelihood of a causal relation between fluid flux and permeability in the deep, ductile crust, where fluid pressures are typically near-lithostatic. It is less obvious that such a relation should pertain in the relatively cool, brittle upper crust, where near-hydrostatic fluid pressures are the norm. We use first-order calculations and numerical modeling to explore the hypothesis that upper-crustal permeability is influenced by the magnitude of external fluid sources, much as lower-crustal permeability is influenced by the magnitude of internal fluid sources. We compare model-generated permeability structures with various observations of crustal permeability. ?? 2008 The Authors Journal compilation ?? 2008 Blackwell Publishing Ltd.

Rojstaczer, S.A.; Ingebritsen, S.E.; Hayba, D.O.

2008-01-01

14

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

15

Modeling and Control of Multi-Contact Centers of Pressure and Internal Forces in Humanoid Robots  

E-print Network

Modeling and Control of Multi-Contact Centers of Pressure and Internal Forces in Humanoid Robots- eling and control of internal forces and moments produced during multi-contact interactions between for the control of internal forces is suggested and illustrated on the Asimo humanoid robot. The new controller

Sentis, Luis

16

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

17

Foot Forces during Treadmill Exercise on the International Space Station  

NASA Technical Reports Server (NTRS)

Exercise has been the primary countermeasure to combat musculoskeletal changes during the approximately 6 month missions to the International Space Station (ISS). However, these countermeasures have not been successful in preventing loss of bone mineral density in the spine and hip of astronauts. We examined lower extremity loading during typical bouts of on-orbit exercise performed by 4 ISS crew members on the ISS treadmill (TVIS) and during locomotor activities on earth (1g). In-shoe forces were monitored at 128Hz using force-measuring insoles placed inside the shoes of the exercising crewmember, stored temporarily on Flash cards, and down-linked via satellite for analysis. Custom software extracted peak forces from up to 30 minutes of locomotor activity. All on-orbit loading conditions for walking and running resulted in peak forces and impact loading rates that were significantly less than those measured in 1g. Typical single leg loads on-orbit in walking and running were 0.860 plus or minus 0.04 body weights (BW) and 1.339 plus or minus 0.07 BW compared to 1.2 plus or minus 0.036 BW and 2.36 plus or minus 0.07 BW in 1g BW respectively. These results indicate that typical exercise on the ISS treadmill does not generate 1g-like loading conditions. This may be partly responsible for the loss of bone mineral density that has been observed in these and other crew members. Since on-orbit treadmill exercise requires a restraining load to return the crew member to the treadmill surface, more studies are required to enable comfortable full body weight loading to be applied.

Cavanagh, Peter R.; Rice, Andrea J.; Maender, Christian C.; Gopalakrishnan, Raghavan; Genc, Kerim O.; Kuklis, Matthew

2006-01-01

18

Modeling and control of multi-contact centers of pressure and internal forces in humanoid robots  

Microsoft Academic Search

This paper presents a methodology for the mod- eling and control of internal forces and moments produced during multi-contact interactions between humanoid robots and the environment. The approach is based on the virtual linkage model which provides a physical representation of the internal forces and moments acting between the various contacts. The forces acting at the contacts are decomposed into

Luis Sentis; Oussama Khatib

2009-01-01

19

Redesigning Residency Training in Internal Medicine: The Consensus Report of the Alliance for Academic Internal Medicine Education Redesign Task Force  

Microsoft Academic Search

Because of numerous criticisms of the content and structure of residency training, redesigning graduate medical education (GME) has become a high priority for the internal medicine community. From 2005 to 2007, the leadership of the internal medicine community, working under the auspices of the Alliance for Academic Internal Medicine Education Redesign Task Force, developed six recommendations it will pursue to

Frederick J. Meyers; Steven E. Weinberger; John P. Fitzgibbons; Jeffrey Glassroth; F. Daniel Duffy; Charles P. Clayton

2007-01-01

20

Evaluation of Bite Force After Open Reduction and Internal Fixation Using Microplates  

PubMed Central

The primary aim of this study is to determine maximum bite force in molar and incisor regions of healthy individuals, to evaluate the bite force after open reduction and internal fixation of mandibular fractures using micro plates, for a period of up to 6 weeks and to determine the rate of recovery of maximum bite force in an Indian population. PMID:24910656

Kumar, S Tharani; Saraf, Saurabh; Devi, S Prasanna

2013-01-01

21

On the calculation of internal forces in mechanically stressed polyatomic molecules  

NASA Astrophysics Data System (ADS)

We discuss how to define and to compute internal forces in a molecule subjected to mechanical stress. Because of the inherently many-body character of intramolecular interactions, internal forces cannot be uniquely defined without specifying a set of internal coordinates used to describe the molecular structure. When such a set is comprised of 3N - 6 interactomic distances (N being the number of atoms) and includes the bond lengths of interest, we show that the associated forces, while satisfying the equation F = ?V/?R (where R is the bond length, F is the internal force in this bond, and V is the potential energy of the molecule), can be determined from the molecular geometry alone. We illustrate these ideas using several toy models ranging from small molecules to a graphene sheet and show that the magnitude of the internal force in a bond is not necessarily a good predictor of its strength in response to mechanical loading. At the same time, analysis of internal forces reveals interesting phenomena such as the force multiplication effect, where weak external forces may, e.g., be used to break strong bonds, and offers insight into the catch-bond phenomenon where chemical reactivity is suppressed through application of a force.

Avdoshenko, Stanislav M.; Konda, Sai Sriharsha M.; Makarov, Dmitrii E.

2014-10-01

22

Instinctual Affective Forces in the Internalization Process: Contributions of Hans Loewald  

Microsoft Academic Search

This article focuses on the role of instinctual\\/affective forces in internalization, a process that both Piaget and Vygotsky identified as the primary mechanism underlying the development of higher mental structures and functions. Although important differences exist in these two theorists’ conceptualizations of internalization, they shared the view that internalization builds cognitive structure by reconstituting external interactions in a new form

Anne L. Dean

1994-01-01

23

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 words: internal model; feedforward control; reaching movement; dynamics; grip force; load force; hand of an internal model of the motor apparatus in planning and controlling arm movements. In particular, we tested

Flanagan, Randy

24

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

25

Atomic force and total internal reflection fluorescence microscopy for the study of force transmission in endothelial cells.  

PubMed Central

This paper describes the combined use of atomic force microscopy (AFM) and total internal reflection fluorescence microscopy (TIRFM) to examine the transmission of force from the apical cell membrane to the basal cell membrane. A Bioscope AFM was mounted on an inverted microscope, the stage of which was configured for TIRFM imaging of fluorescently labeled human umbilical vein endothelial cells (HUVECs). Variable-angle TIRFM experiments were conducted to calibrate the coupling angle with the depth of penetration of the evanescent wave. A measure of cellular mechanical properties was obtained by collecting a set of force curves over the entire apical cell surface. A linear regression fit of the force-indentation curves to an elastic model yields an elastic modulus of 7.22 +/- 0. 46 kPa over the nucleus, 2.97 +/- 0.79 kPa over the cell body in proximity to the nucleus, and 1.27 +/- 0.36 kPa on the cell body near the edge. Stress transmission was investigated by imaging the response of the basal surface to localized force application over the apical surface. The focal contacts changed in position and contact area when forces of 0.3-0.5 nN were applied. There was a significant increase in focal contact area when the force was removed (p < 0.01) from the nucleus as compared to the contact area before force application. There was no significant change in focal contact coverage area before and after force application over the edge. The results suggest that cells transfer localized stress from the apical to the basal surface globally, resulting in rearrangement of contacts on the basal surface. PMID:10733955

Mathur, A B; Truskey, G A; Reichert, W M

2000-01-01

26

Internal forces of concrete floor diaphragms in multi- storey buildings  

Microsoft Academic Search

Simplistic design methods are commonly employed by design engineers to determine the approximate magnitude and distribution of inertial forces in reinforced concrete floor diaphragms of multi-storey buildings. Various researchers have identified that the commonly employed simplistic design method, the Equivalent Static Analysis method, in some cases, provides a poor representation of the true structural response. This research investigates the magnitude

D. R. Gardiner; D. K. Bull; A. J. Carr

27

Study on Structural Internal Force Response of Suspension Bridge Pylon under Wind Loads  

NASA Astrophysics Data System (ADS)

Xihoumen Bridge is a suspension bridge with main span of 1650 m, and the bridge pylon is 211.286 m high. The problem of structural internal force response of bridge pylon under wind loads is a major concern in design as the bridge is located in a typhoon-prone region. Firstly, according to two status of the north bridge pylon, namely the construction longest cantilever stage and the bridge service stage under the wind velocity with a return period of 100 years, three-dimensional finite element model of pylon was established. Then, considering two types of wind yaw angles of 0° and 90°, the structural internal force response under wind loads and the gust response factor of the pylon were studied. The static structural internal force responses were computed by the static finite element method, while the fluctuating structural buffeting internal force responses were computed by the dynamic finite element method and the pseudo-excitation method. The results show that the structural internal force responses of the pylon gradually increased with the lower elevation. On the above two status of the north bridge pylon, in the case of wind yaw angle of 0°, the structural longitudinal bending moment in pylon bottom cross-section were 38529 t?m and 50158 t?m, respectively; while in the case of wind yaw angle of 90°, the structural lateral bending moment in pylon bottom cross-section were 70722 t?m and 21991 t?m, respectively.

Gao, Liu; Tian-cheng, Liu; Qing-hai, Feng; Shang-you, Cheng; Yi, Li

2010-05-01

28

Force.  

ERIC Educational Resources Information Center

Discusses pupil misconceptions concerning forces. Summarizes some of Assessment of Performance Unit's findings on meaning of (1) force, (2) force and motion in one dimension and two dimensions, and (3) Newton's second law. (YP)

Gamble, Reed

1989-01-01

29

Anomalies of ac driven solitary waves with internal modes: Nonparametric resonances induced by parametric forces  

E-print Network

We study the dynamics of kinks in the $\\phi^4$ model subjected to a parametric ac force, both with and without damping, as a paradigm of solitary waves with internal modes. By using a collective coordinate approach, we find that the parametric force has a non-parametric effect on the kink motion. Specifically, we find that the internal mode leads to a resonance for frequencies of the parametric driving close to its own frequency, in which case the energy of the system grows as well as the width of the kink. These predictions of the collective coordinate theory are verified by numerical simulations of the full partial differential equation. We finally compare this kind of resonance with that obtained for non-parametric ac forces and conclude that the effect of ac drivings on solitary waves with internal modes is exactly the opposite of their character in the partial differential equation.

Niurka R. Quintero; Angel Sanchez; Franz G. Mertens

2001-07-19

30

Ultrasonic imaging of internal vibration of soft tissue under forced vibration  

Microsoft Academic Search

An imaging system that can display both the amplitude and phase maps of internal vibration in soft tissues for forced low-frequency vibration is described. In this method, low-frequency sinusoidal vibration of frequency under several hundred hertz is applied from the surface of the sample and the resulting movement in it is measured from the Doppler frequency shift of the simultaneously

YOSHIKI YAMAKOSHI; JUNICHI SATO; TAKUSO SATO

1990-01-01

31

Internal Variability of the Winter Stratosphere. Part I: Time-Independent Forcing R. K. SCOTT  

E-print Network

which the radiatively driven cyclonic circulation of the winter stratospheric polar vortex undergoesInternal Variability of the Winter Stratosphere. Part I: Time-Independent Forcing R. K. SCOTT North conditions strengthens the polar vortex, and planetary wave breaking, which weakens it. The results from

Cambridge, University of

32

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

33

Force  

NSDL National Science Digital Library

Instructions: This is a webquest designed to help students understand force. It is specifically meant to teach the idea that the greater the force applied to an object the greater the change in speed or direction of the object depending on the mass. This is also known as Newton's Second Law of Motion. Lets Learn about Force! For this project your students will understand force. They will use Newton's second law to solve the problem presented. UT Core Curriculum: Science 3rd Grade. Standard 3- Students will understand the relationship between the force applied to an object and resulting motion of the ...

Mrs. Brownie

2010-04-07

34

Calculation of internal valence force constants for XY 4 ( Td) tetrahedral molecules  

NASA Astrophysics Data System (ADS)

Valence force constants have been calculated in terms of simple dependent rectilinear internal coordinates for a series of XY 4 tetrahedral molecules that have been studied from a vibrational point of view. These molecules include the tetrahydrides of carbon, silicon, germanium and tin, and the tetrafluorides of carbon, silicon and germanium. Using the most recent and reliable force constants in symmetry coordinates, the pure vibrational force field has been arrived at by applying Kuczera's treatment. The results show that the seven FR dependent constants are reduced to five F*R independent constants; the same occurs for the F0S independent force constants. The relationships f*r? = - f*'r? and f*'?? = - f*? - 4 f*?? are obtained from the sum rule in Kuczera's treatment. On the basis of Wilson's S vectors and from the interactions between the displacement coordinates, a method is proposed here to obtain the above relationships. This allows individual values to be assigned to the bending, bending—bending and bending—stretching force constants for the above-mentioned molecules, without the need for recourse to any model whatsoever. Likewise, in each case we have attempted to obtain an empirical function to fit the force constant values dependent on the bond lengths. This method allows us to some extent to predict the values of the force constants for some tetrahydride molecules of this group, which has not yet been studied experimentally.

Fernández Gómez, M.; López González, J. J.; Rajamanickam, N.; Martínez-Torres, E.

1992-08-01

35

Acquisition and contextual switching of multiple internal models for different viscous force fields.  

PubMed

Humans can learn an enormous number of motor behaviors in different environments. To explain this, the MOSAIC model proposes that multiple internal models are acquired in the brain, which can be switched. However, previous behavioral studies that examined arm-movement adaptations to multiple environments reported a rather limited learning capability. Hitherto, humans have been believed incapable of learning two opposite viscous force fields, which are both dynamic transformations and depend on the same state variable, presented in a random order with only a visual cue. In contrast, this study found that humans are capable of this. Elbow joint movements to specified targets were perturbed by either resistive or assistive viscous force fields generated by a single degree-of-freedom manipulandum. The resistive or assistive viscous force fields were cued by a blue or red color on a CRT screen, respectively. The squared distance between the end point and the target, and the variance of the joint angular velocities were used as kinematic performance indices. These movement errors decreased significantly as a function of the training days. Aftereffects and learning consolidation were demonstrated in the random presentation of the two force fields. Consequently, humans were able to learn the multiple and distinct internal models of the two force fields and appropriately switch them even for a random presentation cued only by color after several days of training. This study suggests that none of the previously proposed conditions for multiple internal model learning are necessary prerequisites, and indicates that the difficulty in learning is determined by the balance between the effectiveness of contextual information and the similarity of force fields. PMID:12804793

Wada, Yasuhiro; Kawabata, Yasuhiro; Kotosaka, Shinya; Yamamoto, Kenji; Kitazawa, Shigeru; Kawato, Mitsuo

2003-07-01

36

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

37

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; Hæggström, Edward

2014-03-01

38

Statistical thermodynamics of internal rotation in a hindering potential of mean force obtained from computer simulations.  

PubMed

A method of statistical estimation is applied to the problem of one-dimensional internal rotation in a hindering potential of mean force. The hindering potential, which may have a completely general shape, is expanded in a Fourier series, the coefficients of which are estimated by fitting an appropriate statistical-mechanical distribution to the random variable of internal rotation angle. The function of reduced moment of inertia of an internal rotation is averaged over the thermodynamic ensemble of atomic configurations of the molecule obtained in stochastic simulations. When quantum effects are not important, an accurate estimate of the absolute internal rotation entropy of a molecule with a single rotatable bond is obtained. When there is more than one rotatable bond, the "marginal" statistical-mechanical properties corresponding to a given internal rotational degree of freedom are reduced. The method is illustrated using Monte Carlo simulations of two public health relevant halocarbon molecules, each having a single internal-rotation degree of freedom, and a molecular dynamics simulation of an immunologically relevant polypeptide, in which several dihedral angles are analyzed. PMID:12820124

Hnizdo, Vladimir; Fedorowicz, Adam; Singh, Harshinder; Demchuk, Eugene

2003-07-30

39

The future of general internal medicine. Report and recommendations from the Society of General Internal Medicine (SGIM) Task Force on the Domain of General Internal Medicine.  

PubMed

The Society of General Internal Medicine asked a task force to redefine the domain of general internal medicine. The task force believes that the chaos and dysfunction that characterize today's medical care, and the challenges facing general internal medicine, should spur innovation. These are our recommendations: while remaining true to its core values and competencies, general internal medicine should stay both broad and deep-ranging from uncomplicated primary care to continuous care of patients with multiple, complex, chronic diseases. Postgraduate and continuing education should develop mastery. Wherever they practice, general internists should be able to lead teams and be responsible for the care their teams give, embrace changes in information systems, and aim to provide most of the care their patients require. Current financing of physician services, especially fee-for-service, must be changed to recognize the value of services performed outside the traditional face-to-face visit and give practitioners incentives to improve quality and efficiency, and provide comprehensive, ongoing care. General internal medicine residency training should be reformed to provide both broad and deep medical knowledge, as well as mastery of informatics, management, and team leadership. General internal medicine residents should have options to tailor their final 1 to 2 years to fit their practice goals, often earning a certificate of added qualification (CAQ) in special generalist fields. Research will expand to include practice and operations management, developing more effective shared decision making and transparent medical records, and promoting the close personal connection that both doctors and patients want. We believe these changes constitute a paradigm shift that can benefit patients and the public and reenergize general internal medicine. PMID:14748863

Larson, Eric B; Fihn, Stephan D; Kirk, Lynne M; Levinson, Wendy; Loge, Ronald V; Reynolds, Eileen; Sandy, Lewis; Schroeder, Steven; Wenger, Neil; Williams, Mark

2004-01-01

40

Foraging at the Edge of Chaos: Internal Clock versus External Forcing  

NASA Astrophysics Data System (ADS)

Activity rhythms in animal groups arise both from external changes in the environment, as well as from internal group dynamics. These cycles are reminiscent of physical and chemical systems with quasiperiodic and even chaotic behavior resulting from “autocatalytic” mechanisms. We use nonlinear differential equations to model how the coupling between the self-excitatory interactions of individuals and external forcing can produce four different types of activity rhythms: quasiperiodic, chaotic, phase locked, and displaying over or under shooting. At the transition between quasiperiodic and chaotic regimes, activity cycles are asymmetrical, with rapid activity increases and slower decreases and a phase shift between external forcing and activity. We find similar activity patterns in ant colonies in response to varying temperature during the day. Thus foraging ants operate in a region of quasiperiodicity close to a cascade of transitions leading to chaos. The model suggests that a wide range of temporal structures and irregularities seen in the activity of animal and human groups might be accounted for by the coupling between collectively generated internal clocks and external forcings.

Nicolis, S. C.; Fernández, J.; Pérez-Penichet, C.; Noda, C.; Tejera, F.; Ramos, O.; Sumpter, D. J. T.; Altshuler, E.

2013-06-01

41

Forces  

NSDL National Science Digital Library

The representation depicts what forces are and how they can change the motion and shape of objects in an animated slide show. This resource also includes an interactive test and review of the material, and can be downloaded for offline use.

42

Report of the Cost Assessment and Validation Task Force on the International Space Station  

NASA Technical Reports Server (NTRS)

The Cost Assessment and Validation (CAV) Task Force was established for independent review and assessment of cost, schedule and partnership performance on the International Space Station (ISS) Program. The CAV Task Force has made the following key findings: The International Space Station Program has made notable and reasonable progress over the past four years in defining and executing a very challenging and technically complex effort. The Program size, complexity, and ambitious schedule goals were beyond that which could be reasonably achieved within the $2.1 billion annual cap or $17.4 billion total cap. A number of critical risk elements are likely to have an adverse impact on the International Space Station cost and schedule. The schedule uncertainty associated with Russian implementation of joint Partnership agreements is the major threat to the ISS Program. The Fiscal Year (FY) 1999 budget submission to Congress is not adequate to execute the baseline ISS Program, cover normal program growth, and address the known critical risks. Additional annual funding of between $130 million and $250 million will be required. Completion of ISS assembly is likely to be delayed from one to three years beyond December 2003.

1998-01-01

43

Cost Assessment and Validation Task Force on the International Space Station  

NASA Technical Reports Server (NTRS)

The Cost Assessment and Validation (CAV) Task Force was established for independent review and assessment of cost, schedule and partnership performance on the International Space Station (ISS) Program. The CAV Task Force has made the following key findings: The International Space Station Program has made notable and reasonable progress over the past four years in defining and executing a very challenging and technically complex effort; The Program, size, complexity, and ambitious schedule goals were beyond that which could be reasonably achieved within the $2.1 billion annual cap or $17.4 billion total cap; A number of critical risk elements are likely to have an adverse impact on the International Space Station cost and schedule; The schedule uncertainty associated with Russian implementation of joint Partnership agreements is the major threat to the ISS Program; The Fiscal Year (FY) 1999 budget submission to Congress is not adequate to execute the baseline ISS Program, cover normal program, growth, and address the known critical risks. Additional annual funding of between $130 million and $250 million will be required; and Completion of ISS assembly is likely to be delayed from, one to three years beyond December 2003.

1998-01-01

44

Internal forces in nondegenerate two-dimensional electron systems C. Fang-Yen* and M. I. Dykman  

E-print Network

, and the phase transition between the two. Extensive MC simulations of nondegenerate 2D electron sys- tems wereInternal forces in nondegenerate two-dimensional electron systems C. Fang-Yen* and M. I. Dykman the Coulomb forces that drive individual electrons in a two-dimensional normal electron fluid and a Wigner

Fang-Yen, Christopher

45

Report by the International Space Station (ISS) Management and Cost Evaluation (IMCE) Task Force  

NASA Technical Reports Server (NTRS)

The International Space Station (ISS) Management and Cost Evaluation Task Force (IMCE) was chartered to conduct an independent external review and assessment of the ISS cost, budget, and management. In addition, the Task Force was asked to provide recommendations that could provide maximum benefit to the U.S. taxpayers and the International Partners within the President's budget request. The Task Force has made the following principal findings: (1) The ISS Program's technical achievements to date, as represented by on-orbit capability, are extraordinary; (2) The Existing ISS Program Plan for executing the FY 02-06 budget is not credible; (3) The existing deficiencies in management structure, institutional culture, cost estimating, and program control must be acknowledged and corrected for the Program to move forward in a credible fashion; (4) Additional budget flexibility, from within the Office of Space Flight (OSF) must be provided for a credible core complete program; (5) The research support program is proceeding assuming the budget that was in place before the FY02 budget runout reduction of $1B; (6) There are opportunities to maximize research on the core station program with modest cost impact; (7) The U.S. Core Complete configuration (three person crew) as an end-state will not achieve the unique research potential of the ISS; (8) The cost estimates for the U.S.-funded enhancement options (e.g., permanent seven person crew) are not sufficiently developed to assess credibility. After these findings, the Task Force has formulated several primary recommendations which are published here and include: (1) Major changes must be made in how the ISS program is managed; (2) Additional cost reductions are required within the baseline program; (3) Additional funds must be identified and applied from the Human Space Flight budget; (4) A clearly defined program with a credible end-state, agreed to by all stakeholders, must be developed and implemented.

Young, A. Thomas; Kellogg, Yvonne (Technical Monitor)

2001-01-01

46

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

47

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

48

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; González-Pinto, Ana; Goldberg, Joseph F.; Yildiz, Ay?egül; 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.; Vázquez, Gustavo; Perlis, Roy H.; Ketter, Terence A.; Cassidy, Frederick; Akiskal, Hagop; Azorin, Jean-Michel; Valentí, Marc; Mazzei, Diego Hidalgo; Lafer, Beny; Kato, Tadafumi; Mazzarini, Lorenzo; Martínez-Aran, Anabel; Parker, Gordon; Souery, Daniel; Özerdem, Ay?egül; 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, Flávio; Vieta, Eduard

2014-01-01

49

Internal and external forcing of sea level variability in the Black Sea  

NASA Astrophysics Data System (ADS)

The variability of sea level in the Black Sea is forced by a combination of internal and external processes of atmospheric, oceanic, and terrestrial origin. We use a combination of satellite altimetry and gravity, tide gauge, river discharge, and atmospheric re-analysis data to provide a comprehensive up-to-date analysis of sea level variability in the Black Sea and to quantify the role of different environmental factors that force the variability. The Black Sea is part of a large-scale climatic system that includes the Mediterranean and the North Atlantic. The seasonal sea level budget shows similar contributions of fresh water fluxes (precipitation, evaporation, and river discharge) and the Black Sea outflow, while the impact of the net surface heat flux is smaller although not negligible. We find that the nonseasonal sea level time series in the Black and Aegean seas are significantly correlated, the latter leading by 1 month. This lag is attributed to the adjustment of sea level in the Black Sea to externally forced changes of sea level in the Aegean Sea and to the impact of river discharge. The nonseasonal sea level budget in the Black Sea is dominated by precipitation and evaporation over the sea itself, but external processes such as river discharge and changes in the outflow can also cause some large synoptic-scale sea level anomalies. Sea level is strongly coupled to terrestrial water storage over the Black Sea drainage basin, which is modulated by the North Atlantic Oscillation (NAO). We show that during the low/high NAO southwesterly/northeasterly winds near the Strait of Gibraltar and southerly/northerly winds over the Aegean Sea are able to dynamically increase/decrease sea level in the Mediterranean and Black seas, respectively.

Volkov, Denis L.; Landerer, Felix W.

2015-02-01

50

[Global and historical development of the IMETAF (International Molecular Epidemiology Task Force) in Mexico].  

PubMed

IMETAF or International Molecular Epidemiology Task Force was created upon the enthusiasm of Janice Dorman, molecular epidemiologist at Pittsburgh University. Also, she was in charge of the WHO type I Diabetes world project called DIAMOND. As a result of this project done with Mexican scientists. The Scientific Committee of IMETAF was formed on July 28, 1993. The activities began. A national infrastructure survey was done to analyze the epidemiology and molecular biology capabilities; a directory of scientist in epidemiology and molecular biology was elaborated; a theoric and practical course on molecular epidemiology was organized during 1996 and a second one will be held in 1997; and a series of Workshops were done: cancer and leukemias; bacterial diseases; trypanosomiosis and leishmaniosis and viral diseases. The results of these academic activities were brought to the National Academy of Medicine to a 2 days workshop and to an International Symposium called Projection of molecular epidemiology in medicine, held on April 17, 1996. The papers are published in this number. The goal of IMETAF will continue promoting transfer of technology, stimulating formal training in molecular epidemiology and helping getting funds for collaborative projects. PMID:9504097

Gorodezky, C

1997-01-01

51

Internal Dynamics and Boundary Forcing Characteristics Associated with Interannual Variability of the Asian Summer Monsoon  

NASA Technical Reports Server (NTRS)

In this paper, we present a description of the internal dynamics and boundary forcing characteristics of two major components of the Asian summer monsoon (ASM), i.e., the South Asian (SAM) and the Southeast-East Asian monsoon (SEAM). The description is based on a new monsoon-climate paradigm in which the variability of ASM is considered as the outcome of the interplay of a "fast" and an "intermediate" monsoon subsystem, under the influenced of the "slow" varying external forcings. Two sets of regional monsoon indices derived from dynamically consistent rainfall and wind data are used in this study. For SAM, the internal dynamics is represented by that of a "classical" monsoon system where the anomalous circulation is governed by Rossby-wave dynamics, i.e., generation of anomalous vorticity induced by an off-equatorial heat source is balanced by planetary vorticity advection. On the other hand, the internal dynamics of SEAM is characterized by a "hybrid" monsoon system featuring multi-cellular meridional circulation over the East Asian section, extending from the deep tropics to midlatitudes. These meridional-cells link tropical heating to extratropical circulation system via the East Asian jetstream, and are responsible for the characteristic occurrences of zonally oriented anomalous rainfall patterns over East Asian and the subtropical western Pacific. In the extratropical regions, the major upper level vorticity balance is by anomalous vorticity advection and generation by the anomalous divergent circulation. A consequence of this is that compared to SAM, the SEAM is associated with stronger teleconnection patterns to regions outside the ASM. A strong SAM is linked to basin-scale sea surface temperature (SST) fluctuation with significant signal in the equatorial eastern Pacific. During the boreal spring SST warming in the Arabian Sea and the subtropical western Pacific may lead to a strong SAM. For SEAM, interannual variability is tied to SSTA over the Sea of Japan and the South China Sea regions, while the linkage to equatorial basin-scale SSTA is weak at best. A large scale SSTA dipole with warming (cooling) in the subtropical central (eastern) Pacific foreshadows a strong SEAM.

Lau, K.- M.; Kim, K.-M.; Yang, S.

1998-01-01

52

DYNAMIC FE MODEL OF SITTING MAN ADJUSTABLE TO BODY HEIGHT, BODY MASS AND POSTURE USED FOR CALCULATING INTERNAL FORCES IN THE LUMBAR VERTEBRAL DISKS  

Microsoft Academic Search

Long-term whole-body vibrations can cause degeneration of the lumbar spine. Therefore existing degeneration has to be assessed as well as industrial working places to prevent further damage. Hence, the mechanical stress in the lumbar spine—especially in the three lower vertebrae—has to be known. This stress can be expressed as internal forces. These internal forces cannot be evaluated experimentally, because force

S. Pankoke; B. Buck; H. P. Woelfel

1998-01-01

53

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 in situ 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

54

Trends of Internal Forces in Concrete Floor Diaphragms of Multi-storey Structures During Seismic Shaking  

Microsoft Academic Search

Simplistic design methods are commonly employed by design engineers to determine the approximate magnitude and distribution of inertial forces in reinforced concrete floor diaphragms of multi-storey buildings. Various res earchers have identified that the commonly employed simplistic design method, the Equivalent Static Analysis (ESA) method, in some cases, provides an inadequate outcome for the estimation of forces that develop in

D. R. Gardiner

55

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

56

Selection and Control of Object Motion and Internal Force for Grasping/Manipulation by Multi-fingered Robot Hands with Constrained DOF  

NASA Astrophysics Data System (ADS)

This paper is concerned with a control design method for multi-fingered robot hands, whose degrees of freedom (DOF) are not enough to control all of the components of the object motion and the internal force. In the control design of the multi-fingered robot hands, controllers are usually designed for the variables with respect to the object motion and the internal force, under the assumption that the systems have enough DOF to control all the components of them. However, if we consider the systems with fewer DOF, although the control variables directly linked to the components of the object motion and the internal force will be preferable for the grasping/manipulation tasks, control design methodology to meet such requirements has not been established yet. In this paper, we consider the systems whose DOF are not enough to control all of the components of the object motion and the internal force, and propose a control design method whose control variables are directly linked to the components of the object motion and the internal force. The control variables can be specified as functions of the object motion and the internal force directly, and a linearizing compensator for the variables is derived. A numerical example of a robot hand with interlocking joints is shown to prove effectiveness of the proposed method.

Nagase, Kenji; Fujita, Kenji

57

Guidelines and Ethical Considerations for Assessment Center Operations: International Task Force on Assessment Center Guidelines.  

ERIC Educational Resources Information Center

This update of the International Personnel Management Association's guidelines for organizational psychologists, human resource management specialists, and others addresses elements of assessment centers, policy statements, assessor training, informed participation, and participants' rights. (SK)

Public Personnel Management, 2000

2000-01-01

58

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

59

On the determination of the internal magnetic structure by magnetic force microscopy  

Microsoft Academic Search

In this contribution it is proven mathematically that it is in principle impossible to determine the magnetic charge distribution inside a magnetic material by a method which measures the stray field outside the sample, such as magnetic force microscopy (MFM). A general source of stray field, E?, is defined and it is shown that different solutions can be found for

Bas Vellekoop; Leon Abelmann; Steffen Porthun; Cock Lodder

1998-01-01

60

On the determination of the internal magnetic structure by magnetic force microscope  

Microsoft Academic Search

In this contribution it is proven mathematically that it is in principle impossible to determine the magnetic charge distribution inside a magnetic material by a method which measures the stray field outside the sample, such as magnetic force microscopy (MFM). A general source of stray field, E?, is defined and it is shown that different solutions can be found for

S. J. L. Vellekoop; L. Abelmann; S. Porthun; J. C. Lodder

1998-01-01

61

Semi-decentralized adaptive fuzzy control for cooperative multirobot systems with H(infinity) motion/internal force tracking performance.  

PubMed

We present a semi-decentralized adaptive fuzzy control scheme for cooperative multirobot systems to achieve H(infinity) performance in motion and internal force tracking. First, we reformulate the overall system dynamics into a fully actuated system with constraints. To cope with both parametric and nonparametric uncertainties, the controller for each robot consists of two parts: 1) model-based adaptive controller; and 2) adaptive fuzzy logic controller (FLC). The model-based adaptive controller handles the nominal dynamics which results in both zero motion and internal force errors for a pure parametric uncertain system. The FLC part handles the unstructured dynamics and external disturbances. An H(infinity) tracking problem defined by a novel performance criterion is given and solved in the sequel. Hence, a robust controller satisfying the disturbance attenuation is derived being simple and singularity-free. Asymptotic convergence is obtained when the fuzzy approximation error is bounded with finite energy. Maintaining the same results, the proposed controller is further simplified for easier implementation. Finally, the numerical simulation results for two cooperative planar robots transporting an object illustrate the expected performance. PMID:18238126

Lian, Kuang-Yow; Chiu, Chian-Song; Liu, P

2002-01-01

62

External push and internal pull forces recruit curvature-sensing N-BAR domain proteins to the plasma membrane.  

PubMed

Many of the more than 20 mammalian proteins with N-BAR domains control cell architecture and endocytosis by associating with curved sections of the plasma membrane. It is not well understood whether N-BAR proteins are recruited directly by processes that mechanically curve the plasma membrane or indirectly by plasma-membrane-associated adaptor proteins that recruit proteins with N-BAR domains that then induce membrane curvature. Here, we show that externally induced inward deformation of the plasma membrane by cone-shaped nanostructures (nanocones) and internally induced inward deformation by contracting actin cables both trigger recruitment of isolated N-BAR domains to the curved plasma membrane. Markedly, live-cell imaging in adherent cells showed selective recruitment of full-length N-BAR proteins and isolated N-BAR domains to plasma membrane sub-regions above nanocone stripes. Electron microscopy confirmed that N-BAR domains are recruited to local membrane sites curved by nanocones. We further showed that N-BAR domains are periodically recruited to curved plasma membrane sites during local lamellipodia retraction in the front of migrating cells. Recruitment required myosin-II-generated force applied to plasma-membrane-connected actin cables. Together, our results show that N-BAR domains can be directly recruited to the plasma membrane by external push or internal pull forces that locally curve the plasma membrane. PMID:22750946

Galic, Milos; Jeong, Sangmoo; Tsai, Feng-Chiao; Joubert, Lydia-Marie; Wu, Yi I; Hahn, Klaus M; Cui, Yi; Meyer, Tobias

2012-08-01

63

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

SciTech Connect

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 NPT Review Conference. The discussions reflected the importance of the NPR for defining the role of US nuclear forces in dealing with 21st century threats and providing guidance for National Nuclear Security Administration (NNSA) and Department of Defense (DoD) programs and, for many but not all participants, highlighted its role in the successful outcome of the NPT RevCon. There was widespread support for the NPR and its role in developing the foundations for a sustainable nuclear-weapon program that addresses nuclear weapons, infrastructure and expertise in the broader nonproliferation, disarmament and international security contexts. However, some participants raised concerns about its implementation and its long-term effectiveness and sustainability.

Pilat, Joseph F [Los Alamos National Laboratory

2010-12-08

64

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

65

Surface structure. Subatomic resolution force microscopy reveals internal structure and adsorption sites of small iron clusters.  

PubMed

Clusters built from individual iron atoms adsorbed on surfaces (adatoms) were investigated by atomic force microscopy (AFM) with subatomic resolution. Single copper and iron adatoms appeared as toroidal structures and multiatom clusters as connected structures, showing each individual atom as a torus. For single adatoms, the toroidal shape of the AFM image depends on the bonding symmetry of the adatom to the underlying structure [twofold for copper on copper(110) and threefold for iron on copper(111)]. Density functional theory calculations support the experimental data. The findings correct our previous work, in which multiple minima in the AFM signal were interpreted as a reflection of the orientation of a single front atom, and suggest that dual and triple minima in the force signal are caused by dimer and trimer tips, respectively. PMID:25791086

Emmrich, Matthias; Huber, Ferdinand; Pielmeier, Florian; Welker, Joachim; Hofmann, Thomas; Schneiderbauer, Maximilian; Meuer, Daniel; Polesya, Svitlana; Mankovsky, Sergiy; Ködderitzsch, Diemo; Ebert, Hubert; Giessibl, Franz J

2015-04-17

66

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

67

Turbofan forced mixer-nozzle internal flowfield. Volume 2: Computational fluid dynamic predictions  

NASA Technical Reports Server (NTRS)

A general program was conducted to develop and assess a computational method for predicting the flow properties in a turbofan forced mixed duct. The detail assessment of the resulting computer code is presented. It was found that the code provided excellent predictions of the kinematics of the mixing process throughout the entire length of the mixer nozzle. The thermal mixing process between the hot core and cold fan flows was found to be well represented in the low speed portion of the flowfield.

Werle, M. J.; Vasta, V. N.

1982-01-01

68

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

69

Joining forces: Collaborating internationally to deliver high-quality, online postgraduate education in pain management  

PubMed Central

The effective management of pain is a complex and costly global issue, requiring a range of innovative educational strategies to enable culturally appropriate and high-quality health care provision. In response to this issue, the Pain Management Research Institute at the University of Sydney (Sydney, Australia) has established several strategic alliances with other overseas universities to deliver online postgraduate education in pain management. The present article discusses the rationale for joining forces, and the approach adopted in creating and maintaining these alliances. It also provides insights into the benefits, challenges and opportunities associated with collaborative educational initiatives of this nature, from institutional, academic and student perspectives. PMID:22184549

Devonshire, Elizabeth; Siddall, Philip J

2011-01-01

70

Joining forces: collaborating internationally to deliver high-quality, online postgraduate education in pain management.  

PubMed

The effective management of pain is a complex and costly global issue, requiring a range of innovative educational strategies to enable culturally appropriate and high-quality health care provision. In response to this issue, the Pain Management Research Institute at the University of Sydney (Sydney, Australia) has established several strategic alliances with other overseas universities to deliver online postgraduate education in pain management. The present article discusses the rationale for joining forces, and the approach adopted in creating and maintaining these alliances. It also provides insights into the benefits, challenges and opportunities associated with collaborative educational initiatives of this nature, from institutional, academic and student perspectives. PMID:22184549

Devonshire, Elizabeth; Siddall, Philip

2011-01-01

71

Turbofan forced mixer-nozzle internal flowfield. Volume 1: A benchmark experimental study  

NASA Technical Reports Server (NTRS)

An experimental investigation of the flow field within a model turbofan forced mixer nozzle is described. Velocity and thermodynamic state variable data for use in assessing the accuracy and assisting the further development of computational procedures for predicting the flow field within mixer nozzles are provided. Velocity and temperature data suggested that the nozzle mixing process was dominated by circulations (secondary flows) of a length scale on the order the lobe dimensions which were associated with strong radial velocities observed near the lobe exit plane. The 'benchmark' model mixer experiment conducted for code assessment purposes is discussed.

Paterson, R. W.

1982-01-01

72

Forcing level effect of internal acoustic excitation on the improvement of airfoil performance  

Microsoft Academic Search

The effects of internal acoustic excitation on the leading edge separated boundary layers and the aerodynamic performance over an airfoil of NACA 63(3)-018 cross section are examined as a function of excitation amplitude and frequency. Tests are conducted in an open-type suction wind tunnel at the Reynolds number of 300,000. Experimental results indicate that the flow separation is suppressed at

F. B. Hsiao; R. C. Chang; R. N. Shyu

1990-01-01

73

The mechanism of force generation in myosin: a disorder-to-order transition, coupled to internal structural changes.  

PubMed Central

We propose a molecular mechanism of force generation in muscle, based primarily on site-specific spectroscopic probe studies of myosin heads in contracting muscle fibers and myofibrils. Electron paramagnetic resonance (EPR) and time-resolved phosphorescence anisotropy (TPA) of probes attached to SH1 (Cys 707, in the catalytic domain of the head) have consistently shown that most myosin heads in contracting muscle are dynamically disordered, undergoing large-amplitude rotations in the microsecond time range. Some of these disordered heads are bound to actin, especially in the early (weak-binding, preforce) phase of the ATPase cycle. The small ordered population (10-20%) is rigidly oriented precisely as in rigor, with no other distinct angle observed in contraction or in the presence of intermediate states trapped by nucleotide analogs. These results are not consistent with the classical model in which the entire head undergoes a 45 degree transition between two distinct orientations. Therefore, it has been proposed that the catalytic domain of the myosin head has only one stereospecific (rigor-like) actin-binding angle, and that the head's internal structure changes during force generation, causing the distal light-chain-binding domain to rotate. To test this model, we have performed EPR and TPA studies of probes attached to regulatory light chains (RLCs) in rabbit and scallop myofibrils and fibers. The RLC results confirm the predominance of dynamic (microsecond) rotational disorder in both relaxation and contraction, and show that the different mechanisms of calcium regulation in the two muscles produce different rotational dynamics. In rabbit myofibrils, RLC probes are more dynamically disordered than SH1 probes, especially in rigor and contraction,indicating that the light-chain-binding domain undergoes rotational motions relative to the catalytic domain when myosin heads interact with actin. An SH1-bound spin label, which is sensitive to myosin's internal dynamics, resolves three distinct conformations during contraction, and time-resolved EPR shows that these transitions are coupled to specific steps in the ATPase cycle. We propose that force is generated during contraction by a disorder-to-order transition, in which myosin heads first attach weakly to actin in a nonstereospecific mode characterized by large-scale dynamic disorder, then undergo at least two conformational transitions involving large-scale structural (rotational) changes within the head, culminating in a highly ordered strong-binding state that bears force. Images FIGURE 1 FIGURE 2 FIGURE 3 FIGURE 4 FIGURE 5 PMID:7787056

Thomas, D. D.; Ramachandran, S.; Roopnarine, O.; Hayden, D. W.; Ostap, E. M.

1995-01-01

74

Minimizing distortion and internal forces in truss structures by simulated annealing  

NASA Technical Reports Server (NTRS)

Inaccuracies in the length of members and the diameters of joints of large truss reflector backup structures may produce unacceptable levels of surface distortion and member forces. However, if the member lengths and joint diameters can be measured accurately it is possible to configure the members and joints so that root-mean-square (rms) surface error and/or rms member forces is minimized. Following Greene and Haftka (1989) it is assumed that the force vector f is linearly proportional to the member length errors e(sub M) of dimension NMEMB (the number of members) and joint errors e(sub J) of dimension NJOINT (the number of joints), and that the best-fit displacement vector d is a linear function of f. Let NNODES denote the number of positions on the surface of the truss where error influences are measured. The solution of the problem is discussed. To classify, this problem was compared to a similar combinatorial optimization problem. In particular, when only the member length errors are considered, minimizing d(sup 2)(sub rms) is equivalent to the quadratic assignment problem. The quadratic assignment problem is a well known NP-complete problem in operations research literature. Hence minimizing d(sup 2)(sub rms) is is also an NP-complete problem. The focus of the research is the development of a simulated annealing algorithm to reduce d(sup 2)(sub rms). The plausibility of this technique is its recent success on a variety of NP-complete combinatorial optimization problems including the quadratic assignment problem. A physical analogy for simulated annealing is the way liquids freeze and crystallize. All computational experiments were done on a MicroVAX. The two interchange heuristic is very fast but produces widely varying results. The two and three interchange heuristic provides less variability in the final objective function values but runs much more slowly. Simulated annealing produced the best objective function values for every starting configuration and was faster than the two and three interchange heuristic.

Kincaid, Rex K.

1989-01-01

75

Dynamic fe Model of Sitting Man Adjustable to Body Height, Body Mass and Posture Used for Calculating Internal Forces in the Lumbar Vertebral Disks  

NASA Astrophysics Data System (ADS)

Long-term whole-body vibrations can cause degeneration of the lumbar spine. Therefore existing degeneration has to be assessed as well as industrial working places to prevent further damage. Hence, the mechanical stress in the lumbar spine—especially in the three lower vertebrae—has to be known. This stress can be expressed as internal forces. These internal forces cannot be evaluated experimentally, because force transducers cannot be implementated in the force lines because of ethical reasons. Thus it is necessary to calculate the internal forces with a dynamic mathematical model of sitting man.A two dimensional dynamic Finite Element model of sitting man is presented which allows calculation of these unknown internal forces. The model is based on an anatomic representation of the lower lumbar spine (L3-L5). This lumber spine model is incorporated into a dynamic model of the upper torso with neck, head and arms as well as a model of the body caudal to the lumbar spine with pelvis and legs. Additionally a simple dynamic representation of the viscera is used. All these parts are modelled as rigid bodies connected by linear stiffnesses. Energy dissipation is modelled by assigning modal damping ratio to the calculated undamped eigenvalues. Geometry and inertial properties of the model are determined according to human anatomy. Stiffnesses of the spine model are derived from static in-vitro experiments in references [1] and [2]. Remaining stiffness parameters and parameters for energy dissipation are determined by using parameter identification to fit measurements in reference [3]. The model, which is available in 3 different postures, allows one to adjust its parameters for body height and body mass to the values of the person for which internal forces have to be calculated.

Pankoke, S.; Buck, B.; Woelfel, H. P.

1998-08-01

76

Treating rheumatoid arthritis to target: recommendations of an international task force  

PubMed Central

Background Aiming at therapeutic targets has reduced the risk of organ failure in many diseases such as diabetes or hypertension. Such targets have not been defined for rheumatoid arthritis (RA). Objective To develop recommendations for achieving optimal therapeutic outcomes in RA. Methods A task force of rheumatologists and a patient developed a set of recommendations on the basis of evidence derived from a systematic literature review and expert opinion; these were subsequently discussed, amended and voted upon by >60 experts from various regions of the world in a Delphi-like procedure. Levels of evidence, strength of recommendations and levels of agreement were derived. Results The treat-to-target activity resulted in 10 recommendations. The treatment aim was defined as remission with low disease activity being an alternative goal in patients with long-standing disease. Regular follow-up (every 1–3 months during active disease) with appropriate therapeutic adaptation to reach the desired state within 3 to a maximum of 6 months was recommended. Follow-up examinations ought to employ composite measures of disease activity which include joint counts. Additional items provide further details for particular aspects of the disease. Levels of agreement were very high for many of these recommendations (?9/10). Conclusion The 10 recommendations are supposed to inform patients, rheumatologists and other stakeholders about strategies to reach optimal outcomes of RA based on evidence and expert opinion. PMID:20215140

Smolen, Josef S; Aletaha, Daniel; Bijlsma, Johannes W J; Breedveld, Ferdinand C; Boumpas, Dimitrios; Burmester, Gerd; Combe, Bernard; Cutolo, Maurizio; de Wit, Maarten; Dougados, Maxime; Emery, Paul; Gibofsky, Alan; Gomez-Reino, Juan Jesus; Haraoui, Boulos; Kalden, Joachim; Keystone, Edward C; Kvien, Tore K; McInnes, Iain; Martin-Mola, Emilio; Montecucco, Carlomaurizio; Schoels, Monika; van der Heijde, Desirée

2010-01-01

77

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

78

PREFACE: NC-AFM 2004: Proceedings of the 7th International Conference on Non-contact Atomic Force Microscopy  

NASA Astrophysics Data System (ADS)

With the ongoing miniaturization of devices and controlled nanostructuring of materials, the importance of atomic-scale information on surfaces and surface properties is growing continuously. The astonishing progress in nanoscience and nanotechnology that took place during the last two decades was in many ways related to recent progress in high-resolution imaging techniques such as scanning tunnelling microscopy and transmission electron microscopy. Since the mid-1990s, non-contact atomic force microscopy (NC-AFM) performed in ultrahigh vacuum has evolved as an alternative technique that achieves atomic resolution, but without the restriction to conducting surfaces of the previously established techniques. Advances of the rapidly developing field of NC-AFM are discussed at annual conferences as part of a series that started in 1998 in Osaka, Japan. This special issue of Nanotechnology is a compilation of original work presented at the 7th International Conference on Non-contact Atomic Force Microscopy that took place in Seattle, USA, 12-15 September 2004. Over the years, the conference grew in size and scope. Atomic resolution imaging of oxides and semiconductors remains an issue. Noticeable new developments have been presented in this regard such as, e.g., the demonstrated ability to manipulate individual atoms. Additionally, the investigation of individual molecules, clusters, and organic materials gains more and more attention. In this context, considerable effort is undertaken to transfer the NC-AFM principle based on frequency modulation to applications in air and liquids with the goal of enabling high-resolution surface studies of biological material in native environments, as well as to reduce the experimental complexity, which so far involves the availability of (costly) vacuum systems. Force spectroscopy methods continue to be improved and are applied to topics such as the imaging of the three-dimensional force field as a function of the distance with atomic resolution, the investigation of near-surface electronic states, the quantification of adhesion forces, and the lateral mapping of surface potentials. The origin of energy dissipation, which is closely related to an in-depth understanding of tip-surface interactions and imaging mechanisms, was the subject of an ongoing discussion and addressed by various theoretical, computational, and experimental contributions. A characteristic of the NC-AFM conference series is the lively and friendly atmosphere, which year after year stimulates scientific discussions between the participants. This time, the programme included 5 invited talks, 84 contributed presentations, and 113 participants; furthermore, three educational lectures were given as part of a pre-conference workshop targeted at NC-AFM newcomers, which was attended by 30 participants. I would like to thank the members of the international steering committee and the programme committee for their continued effort in organizing the meeting. Special thanks go to the chair of the programme and local organizing committees S Fain and the conference manager J Kvamme for making the meeting a success. Financial support is acknowledged from the corporate sponsors MikroMasch USA, Nanonis GmbH, Nanosurf AG, Omicron Nanotechnology, PSIA, Inc., and RHK Technology, as well as from the institutional sponsors National Science Foundation and PNNL/UW Joint Institute for Nanoscience. Finally, I would like to express my gratitude to everyone who participated in assembling this special issue including the authors, the reviewers, and, in particular, the excellent and experienced journal team from the Institute of Physics Publishing headed by Nina Couzin, for devoting their time and efforts so that we could make this issue a useful representation of the progress in NC-AFM while maintaining our tight publication schedule. In conclusion, I would like to mention that the Seattle conference was the first one of the NC-AFM series that took place in the USA. As such, it was part of a series of recent activities within the USA, which will

Schwarz, Udo

2005-03-01

79

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

Ródenas, Consuelo Rosales; Quesada, Juana Vázquez; Torres, Emilio Martínez; González, Juan Jesús López

2014-06-01

80

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

81

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

E-print Network

Forced and Internal Twentieth-Century SST Trends in the North Atlantic* MINGFANG TING, YOCHANAN, two alarming trends in North Atlantic climate have been noted: an increase in the intensity occurred while a significant warming took place in North Atlantic sea surface temperatures (SSTs), thus

82

Forced oscillations of a rotating shaft with nonlinear spring characteristics and internal damping (1\\/2 order subharmonic oscillations and entrainment)  

Microsoft Academic Search

Nonlinear forced oscillations of a rotating shaft with nonlinear spring characteristics and internal damping are studied. In particular, entrainment phenomena at the critical speeds of 1\\/2 order subharmonic oscillations of forward and backward whirling modes are investigated. A self-excited oscillation appears in the wide range above the major critical speed. The amplitude of this oscillation reaches a limit value and

Yukio Ishida; Toshio Yamamoto

1993-01-01

83

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

84

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

85

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

Code of Federal Regulations, 2011 CFR

...true Assistance to foreign forces for claims arising under...113 Assistance to foreign forces for claims arising under...Singaporean, or Australian forces in the United States are processed...from activities of U.S. government personnel. All JAs and...

2011-07-01

86

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

Code of Federal Regulations, 2013 CFR

...false Assistance to foreign forces for claims arising under...113 Assistance to foreign forces for claims arising under...Singaporean, or Australian forces in the United States are processed...from activities of U.S. government personnel. All JAs and...

2013-07-01

87

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

Code of Federal Regulations, 2014 CFR

...false Assistance to foreign forces for claims arising under...113 Assistance to foreign forces for claims arising under...Singaporean, or Australian forces in the United States are processed...from activities of U.S. government personnel. All JAs and...

2014-07-01

88

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

Code of Federal Regulations, 2010 CFR

...true Assistance to foreign forces for claims arising under...113 Assistance to foreign forces for claims arising under...Singaporean, or Australian forces in the United States are processed...from activities of U.S. government personnel. All JAs and...

2010-07-01

89

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

Code of Federal Regulations, 2012 CFR

...true Assistance to foreign forces for claims arising under...113 Assistance to foreign forces for claims arising under...Singaporean, or Australian forces in the United States are processed...from activities of U.S. government personnel. All JAs and...

2012-07-01

90

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

91

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

NASA Astrophysics Data System (ADS)

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 applications. A series of NC-AFM international conferences have greatly contributed to this field. Initiated in Osaka in 1998, the NC-AFM meeting has been followed by annual conferences at Pontresina, Hamburg, Kyoto, Montreal, Dingle, Seattle and Bad Essen. The 9th conference was held in Kobe, Japan, 16-20 July 2006. This special issue of Nanotechnology contains the outstanding contributions of the conference. During the meeting delegates learnt about a number of significant advances. Topics covered atomic resolution imaging of metals, semiconductors, insulators, ionic crystals, oxides, molecular systems, imaging of biological materials in various environments and novel instrumentation. Work also included the characterization of electronic and magnetic properties, tip and cantilever fabrication and characterization, atomic distinction based on analysis of tip-sample interaction, atomic scale manipulation, fabrication of nanostructures using NC-AFM, and related theories and simulations. We are greatly impressed by the increasing number of applications, and convinced that NC-AFM and related techniques are building a bridge to a future nano world, where quantum phenomena will dominate and nano devices will be realized. In addition, a special session on SPM road maps was held as a first trial in the field, where the future prospects of SPM were discussed enthusiastically. The overall success of the NC-AFM 2006 conference was due to the efforts of many individuals and groups with respect to scientific and technological progress, as well as the international exchange among participants. We hope that all of the participants enjoyed the activities of the conference and the town of Kobe. We are indebted to the members of the international steering committee and the local organizing committee for this successful conference. The operation of conference business by the Kobe Convention and Visitors Association, and by the staff in Professor Morita's lab in Osaka University, and Professor Onishi's lab in Kobe University, is greatly acknowledged. We would like to express our sincere gratitude to the 167th committee on Nano-probe Technology of Japan Society for the Promotion of Science, Nanotechnology Researchers Network Center of Japan, Foundation Advanced Technology Institute, Tsutomu Nakauchi Foundation, and all of the exhibitors at the conference for their financial support. The funding from Kobe Advanced ICT Research Center, National Institute of Information and Communications Technology, is greatly appreciated and enabled these proceedings to be published by IOP Publishing (IOP). We also thank the editorial staff of IOP for their professional work in publishing this special issue.

Tomitori, Masahiko; Onishi, Hiroshi

2007-02-01

92

Semidirect radiative forcing of internal mixed black carbon cloud droplet and its regional climatic effect over China  

Microsoft Academic Search

Black carbon (BC) is one of the most important atmospheric aerosols. It can exert a positive radiative forcing by absorbing solar radiation and a negative radiative forcing by acting as cloud condensation nuclei (CCN) at the top of the atmosphere (TOA). Furthermore, cloud droplets with BC can absorb more solar radiation and reduce their single-scattering albedo (SSA), leading to a

B. L. Zhuang; L. Liu; F. H. Shen; T. J. Wang; Y. Han

2010-01-01

93

PREFACE: NC-AFM 2005: Proceedings of the 8th International Conference on Non-Contact Atomic Force Microscopy  

NASA Astrophysics Data System (ADS)

The 8th International Conference on Non-Contact Atomic Force Microscopy, held in Bad Essen, Germany, from 15?18th August 2005, attracted a record breaking number of participants presenting excellent contributions from a variety of scientific fields. This clearly demonstrated the high level of activity and innovation present in the community of NC-AFM researchers and the continuous growth of the field. The strongest ever participation of companies for a NC-AFM meeting is a sign for the emergence of new markets for the growing NC-AFM community; and the high standard of the products presented at the exhibition, many of them brand-new developments, reflected the unbroken progress in technology. The development of novel technologies and the sophistication of known techniques in research laboratories and their subsequent commercialization is still a major driving force for progress in this area of nanoscience. The conference was a perfect demonstration of how progress in the development of enabling technologies can readily be transcribed into basic research yielding fundamental insight with an impact across disciplines. The NC-AFM 2005 scientific programme was based on five cornerstones, each representing an area of vivid research and scientific progress. Atomic resolution imaging on oxide surfaces, which has long been a vision for the catalysis community, appears to be routine in several laboratories and after a period of demonstrative experiments NC-AFM now makes unique contributions to the understanding of processes in surface chemistry. These capabilities also open up new routes for the analysis of clusters and molecules deposited on dielectric surfaces where resolution limits are pushed towards the single atom level. Atomic precision manipulation with the dynamic AFM left the cradle of its infancy and flourishes in the family of bottom-up fabrication nanotechnologies. The systematic development of established and the introduction of new concepts of contrast formation allow the highly resolved measurement of a number of physical properties far beyond the determination of surface topography. The development of techniques allowing atomic resolution dynamic mode imaging in liquids pushes the door open for an atomic precision analysis of biological samples under physiological conditions. In each of these fields, the conference demonstrated cutting-edge results and also provided perspectives for the next steps on the roadmap of NC-AFM towards the development of its full extent. The conference in Bad Essen was made possible by the continuous dedication of the local management and we are most grateful to Frauke Riemann, Joachim Fontaine and the members of the supporting team for the smooth organization. We gratefully appreciate the financial support of the exhibitors, namely Anfatec, HALCYONICS, JEOL, LOT-Oriel, NanoMagnetics, NT-MDT, Omicron, Schaefer Technology, SURFACE, UNISOKU and the local sponsors which enabled us to provide free participation at the conference for ten promising young researchers who had submitted excellent contributions. It was a great pleasure for us to continue our most successful collaboration with Nanotechnology as our partner for the proceedings publication and we would like to thank Ian Forbes and the publishing team for the professional handling of the peer review and all production matters.

Reichling, M.; Mikosch, W.

2006-04-01

94

Business and International Education. A Report Submitted by the Task Force on Business and International Education to Government/Academic Interface Committee. Occasional Paper No.4.  

ERIC Educational Resources Information Center

A study was undertaken of the educational needs of present and future managers of the large number of business firms in the United States that are or will be affected by economic and political environments abroad. The task force concluded that most firms, regardless of size and type of operation, will be affected by economic and political…

American Council on Education, Washington, DC. International Education Project.

95

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 patient’s 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

96

Understanding the Programmatic and Contextual Forces That Influence Participation in a Government-Sponsored International Student-Mobility Program  

ERIC Educational Resources Information Center

Although prior research establishes the forces that "push" and "pull" students to participate in foreign study, the transferability of findings from earlier studies is limited by the absence of theoretical grounding. In addition, relatively little is known about how a government-sponsored student mobility program promotes…

Perna, Laura W.; Orosz, Kata; Jumakulov, Zakir; Kishkentayeva, Marina; Ashirbekov, Adil

2015-01-01

97

The relative contributions of radiative forcing and internal climate variability to the late 20th Century winter drying  

E-print Network

we assess how well the models can produce multidecadal trends of realistic magnitude, and apply as to the mechanisms responsible. Did external radiative forcing in the form of rising CO2 and global warming play trend predominantly low frequency natural variability on multidecadal timescales (Schneider et al. 2003

98

International terrorism as a force of homogenization? A constructivist approach to understanding cross-national threat perceptions and responses  

Microsoft Academic Search

Has the emergence of international jihadist terrorism led to common threat perceptions and responses in Europe? The article argues that the homogenization thesis is based around a misguided functionalist notion of a single ‘optimal response’ to an alleged new and potentially catastrophic kind of threat with uniform consequences for all ‘Western’ countries. Drawing on insights from different bodies of literature,

Christoph O Meyer

2009-01-01

99

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

100

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

101

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 Bogotá, 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 Bogotá. 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, Fabián; Aguilar, Marcela; Poppen, Paul J

2013-01-01

102

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 Bogotá, 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 Bogotá. 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

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

2013-01-01

103

Ground Reaction Forces and Gait Parameters during Motorized and Non-Motorized Treadmill Walking and Runing on the International Space Station Treadmill  

NASA Technical Reports Server (NTRS)

Both motorized (T-M) and non-motorized (T-NM) treadmill locomotion are used on the International Space Station (ISS) as countermeasures to the deleterious effects of prolonged weightlessness. However, the ground reaction forces (GRF) and gait parameters of these exercise modes have not been examined. The purpose of this study was to determine if differences in GRF and gait parameters exist while walking (1.34 m/s) and running (3.13 m/s) on T-M and T-NM. Dissimilar GRF and gait parameters suggest that T-M and T-NM locomotion may elicit different physiologic effects. T-NM may result in a reduced stimulus to bone formation due to a lower LR, but an increased energy cost as a result of shorter, more frequent strides. Therefore, the usage of each mode should depend upon the desired training stimulus.

Hagan, Ronald Donald; Norcross, Jason; DeWitt, John; Lee, Stuart M.; McCleary, Frank; Edwards, W. Brent

2006-01-01

104

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

105

Nutritional status of children and adolescents based on body mass index: agreement between World Health Organization and International Obesity Task Force  

PubMed Central

Objective: To investigate the agreement between two international criteria for classification of children and adolescents nutritional status. Methods: The study included 778 girls and 863 boys aged from six to 13 years old. Body mass and height were measured and used to calculate the body mass index. Nutritional status was classified according to the cut-off points defined by the World Health Organization and the International Obesity Task Force. The agreement was evaluated using Kappa statistic and weighted Kappa. Results: In order to classify the nutritional status, the agreement between the criteria was higher for the boys (Kappa 0.77) compared to girls (Kappa 0.61). The weighted Kappa was also higher for boys (0.85) in comparison to girls (0.77). Kappa index varied according to age. When the nutritional status was classified in only two categories - appropriate (thinness + accentuated thinness + eutrophy) and overweight (overweight + obesity + severe obesity) -, the Kappa index presented higher values than those related to the classification in six categories. Conclusions: A substantial agreement was observed between the criteria, being higher in males and varying according to the age. PMID:24676189

Cavazzotto, Timothy Gustavo; Brasil, Marcos Roberto; Oliveira, Vinicius Machado; da Silva, Schelyne Ribas; Ronque, Enio Ricardo V.; Queiroga, Marcos Roberto; Serassuelo, Helio

2014-01-01

106

Anharmonic force constant calculations  

Microsoft Academic Search

The relationship of the anharmonic force constants in curvilinear internal coordinates to the observed vibration-rotation spectrum of a molecule is reviewed. A simplified method of setting up the required non-linear coordinate transformations is described: this makes use of an L tensor, which is a straightforward generalization of the L matrix used in the customary description of harmonic force constant calculations.

A. R. Hoy; I. M. Mills; G. Strey

1972-01-01

107

Data mining of external and internal forcing of fluvial systems for catchment management: A case study on the Red River (Song Hong), Vietnam  

NASA Astrophysics Data System (ADS)

The understanding of river hydromorphological processes has been recognized in the last decades as a priority of modern catchment management, since interactions of natural and anthropogenic forces within the catchment drives fluvial geomorphic processes, which shape physical habitat, affect river infrastructures and influence freshwater ecological processes. The characterization of river hydromorphological features is commonly location and time specific and highly resource demanding. Therefore, its routine application at regional or national scales and the assessment of spatio-temporal changes as reaction to internal and external disturbances is rarely feasible at present. Information ranging from recently available high-resolution remote-sensing data (such as DEM), historic data such as land use maps or aerial photographs and monitoring networks of flow and rainfall, open up novel and promising capacity for basin-wide understanding of dominant hydromorphological drivers. Analysing the resulting multiparametric data sets in their temporal and spatial dimensions requires sophisticated data mining tools to exploit the potential of this information. We propose a novel framework that allows for the quantitative assessment of multiparametric data sets to identify classes of channel reaches characterized by similar geomorphic drivers using remote-sensing data and monitoring networks available in the catchment. This generic framework was applied to the Red River (Song Hong) basin, the second largest basin (87,800 sq.km) in Vietnam. Besides its economic importance, the river is experiencing severe river bed incisions due to recent construction of new dams in the upstream part of the catchment and sand mining in the surrounding of the capital city Hanoi. In this context, characterized by an high development rate, current efforts to increase water productivity and minimize impacts on the fluvial systems by means of focused infrastructure and management measures require a thorough understanding of the fluvial system and, in particular, basin-wide assessment of resilience to human-induced change. . The framework proposed has allowed producing high-dimensional samples of spatially distributed geomorphic drivers at catchment scale while integrating recent and historic point records for the Red River basin. This novel dataset has been then analysed using self-organizing maps (SOM) an artificial neural network model in combination with fuzzy clustering. The above framework is able to identify non-trivial correlations in driving forces and to derive a fuzzy classification at reach scale which represents continuities and discontinuities in the river systems. The use of the above framework allowed analyzing the spatial distribution of geomorphic features at catchment scale, revealing patterns of similarities and dissimilarities within the catchment and allowing a classification of river reaches characterized by similar geomorphic drivers, fluvial processes and response to external forcing. The paper proposes an innovative and promising technique to produce hydromorphological classifications at catchment scale integrating historical and recent available high resolution data. The framework aims at opening the way to a more structured organization and analyses of recently available information on river geomorphic features, so far often missing or rarely exploited. This approach poses the basis to produce efficient databases of river geomorphic features and processes related to natural and anthropogenic drivers. That is a necessity in order to enhance our understanding of the internal and external forces which drive fluvial systems, to assess the resilience and dynamic of river landscapes and to develop the more efficient river management strategies of the future.

Schmitt, Rafael; Bizzi, Simone; Castelletti, Andrea

2013-04-01

108

Criteria for evaluation of disease extent by 123I-metaiodobenzylguanidine scans in neuroblastoma: a report for the International Neuroblastoma Risk Group (INRG) Task Force  

PubMed Central

Background: Neuroblastoma is an embryonic tumour of the sympathetic nervous system, metastatic in half of the patients at diagnosis, with a high preponderance of osteomedullary disease, making accurate evaluation of metastatic sites and response to therapy challenging. Metaiodobenzylguanidine (mIBG), taken into cells via the norepinephrine transporter, provides a sensitive and specific method of assessing tumour in both soft tissue and bone sites. The goal of this report was to develop consensus guidelines for the use of mIBG scans in staging, response assessment and surveillance in neuroblastoma. Methods: The International Neuroblastoma Risk Group (INRG) Task Force, including a multidisciplinary group in paediatric oncology of North and South America, Europe, Oceania and Asia, formed a subcommittee on metastatic disease evaluation, including expert nuclear medicine physicians and oncologists, who developed these guidelines based on their experience and the medical literature, with approval by the larger INRG Task Force. Results: Guidelines for patient preparation, radiotracer administration, techniques of scanning including timing, energy, specific views, and use of single photon emission computed tomography are included. Optimal timing of scans in relation to therapy and for surveillance is reviewed. Validated semi-quantitative scoring methods in current use are reviewed, with recommendations for use in prognosis and response evaluation. Conclusions: Metaiodobenzylguanidine scans are the most sensitive and specific method of staging and response evaluation in neuroblastoma, particularly when used with a semi-quantitative scoring method. Use of the optimal techniques for mIBG in staging and response, including a semi-quantitative score, is essential for evaluation of the efficacy of new therapy. PMID:20424613

Matthay, K K; Shulkin, B; Ladenstein, R; Michon, J; Giammarile, F; Lewington, V; Pearson, A D J; Cohn, S L

2010-01-01

109

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 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, Mg2+-induced switch between two alternative conformations: from ‘open’, elongated morphologies at 0–2 mM Mg2+ concentration to a ‘closed’, comma-shaped conformation at 4–6 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 4–6 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 (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

García-Sacristán, Ana; Moreno, Miguel; Ariza-Mateos, Ascensión; López-Camacho, Elena; Jáudenes, Rosa M.; Vázquez, Luis; Gómez, Jordi; Martín-Gago, José Ángel; Briones, Carlos

2015-01-01

110

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

111

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

2008-01-01

112

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

113

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

114

Force and Motion  

NSDL National Science Digital Library

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

National Science Teachers Association (NSTA)

2007-03-21

115

Centripetal Force  

NSDL National Science Digital Library

This activity is inquiry because students should not yet know the equation for centripetal force. Although they will not exactly derive the equation from this lab, they will determine that there is a direct relationship between force, mass, and velocity,

Michael Horton

2009-05-30

116

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

117

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.

118

Unbalanced Forces  

NSDL National Science Digital Library

The representation describes the effect of unbalanced forces on objects at rest and objects in motion in an animated slide show. This resource also includes an interactive test and review of the material. The slide show is accessed through a link marked "Unbalanced Forces" on the resource page, and the entire resource is downloadable, allowing users to run the slide show offline.

119

Mobile Forces  

NSDL National Science Digital Library

The application of engineering principles is explored in the creation of mobiles. As students create their own mobiles, they take into consideration the forces of gravity and convection air currents. They learn how an understanding of balancing forces is important in both art and engineering design.

2014-09-18

120

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

121

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

122

Analysis of the problem of converting measured amplitude-dependent internal friction to intrinsic values. Detailed study of the case of forced oscillations  

Microsoft Academic Search

A review of the problem of converting measured internal friction to intrinsic values is presented, pointing out the influence of three contributions: the deformation mode of the specimen, its geometry and the mode of operation of the equipment. The solution has been found, up to now, only for some particular cases and only for one mode of operation, that is

B. J. Molinas; F. Povolo

1987-01-01

123

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

124

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

125

The Persistence Length of DNA Is Reached from the Persistence Length of Its Null Isomer through an Internal Electrostatic Stretching Force  

PubMed Central

To understand better the effect of electrostatics on the rigidity of the DNA double helix, we define DNA*, the null isomer of DNA, as the hypothetical structure that would result from DNA if its phosphate groups were not ionized. For the purposes of theoretical analysis, we model DNA* as identical to ordinary DNA but supplemented by a longitudinal compression force equal in magnitude but oppositely directed to the stretching (tension) force on DNA caused by phosphate-phosphate repulsions. The null isomer DNA* then becomes an elastically buckled form of fully ionized DNA. On this basis, we derive a nonadditive relationship between the persistence length P of DNA and the persistence length P* of its null isomer. From the formula obtained we can predict the value of P* if P is known, and we can predict the ionic strength dependence of P under the assumption that P* does not depend on ionic strength. We predict a value of P* for null DNA drastically lower than the value of P for DNA in its ordinary state of fully ionized phosphates. The predicted dependence of P on salt concentration is log-c over most of the concentration range, with no tendency toward a salt-independent value in the range of validity of the theory. The predictions are consistent with much of the persistence-length data available for DNA. Alternate theories of the Odijk-Skolnik-Fixman type, including one by the author, are considered skeptically on the grounds that the underlying model may not be realistic. Specifically, we doubt the accuracy for real polyelectrolytes of the Odijk-Skolnik-Fixman assumption that the polymer structure is invariant to changes in electrostatic forces. PMID:16935960

Manning, Gerald S.

2006-01-01

126

EFFECTS OF A BIRD HAZARD REDUCTION FORCE ON REDUCING BIRD\\/AIRCRAFT STRIKE HAZARDS AT THE ATLANTIC CITY INTERNATIONAL AIRPORT, NJ  

Microsoft Academic Search

Bird-aircraft strikes at the Atlantic City International Airport (ACY) increased from 18 in 1989 to 37 in 1990. The number of bird-aircraft strikes involving gulls (Larus spp.) during this time rose from 6 to 27, a 350% increase. The predominant species involved in bird strikes was the laughing gull (L. atricilla). Pursuant to an interagency agreement between the U.S. Department

Andy J. Montoney; H. Christopher Boggs

1993-01-01

127

Forces Lab  

NSDL National Science Digital Library

In this interactive activity from the Building Big Web site, select one of the actions of squeezing, stretching, bending, sliding, or twisting to explore the forces of compression, tension, shear, and torsion.

WGBH Educational Foundation

2004-01-22

128

Library Resources for International Education. A Report Submitted by the Task Force on Library and Information Resources to the Government/Academic Interface Committee, International Education Project, American Council on Education. Occasional Paper No. 1.  

ERIC Educational Resources Information Center

The purpose of this study is to consider methods for providing adequate library and information services for U. S. international education programs. The state of U.S. library resources for the following eight world-area programs was reviewed to determine common library needs and problems: Africa, East Asia, Latin America, Middle East, South Asia,…

American Council on Education, Washington, DC. International Education Project.

129

Physlet Force Concept Inventory: Forces  

NSDL National Science Digital Library

A large truck breaks down out on the road and receives a push back into town by a small compact car as shown in the animation. Learners are to answer questions regarding forces exerted by the two vehicles.

Wolfgang Christian

130

The Si-H stretching-bending overtone polyads of SiHF3: Assignments, band intensities, internal coordinate force field, and ab initio dipole moment surfaces  

NASA Astrophysics Data System (ADS)

Fourier transform overtone spectra of SiHF3 were recorded in the region of 2500-9000 cm-1 and vibrationally assigned. Experimental intensities were estimated. The 3?1 overtone band at 6753 cm-1 was observed to be more than 10 times weaker than the 4?1 band. A reduced three-dimensional Hamiltonian model in terms of internal coordinates was employed to study the Si-H stretching and bending vibrations including 5?1 and 6?1 which were recently recorded using optoacoustic spectroscopy. Potential energy parameters were optimized by fitting to experimental band centers. The Fermi resonance between the Si-H stretching and bending motions was found to be insignificant. Band intensities were computed using ab initio one- and three-dimensional dipole moment surfaces (DMS) expanded to polynomials in terms of symmetrized internal coordinates. The intensity anomaly of 3?1 is understood as resulting from cancellation of contributions by the linear and quadratic terms in the DMS expansion. The behavior of X-H stretching overtone intensities as excitation increases was also studied in the low and medium energy regions. Whether a rapid or a slow decrease of intensity occurs with increasing excitation depends strongly on the nonlinearity of the DMS. For some molecules, there is an almost complete cancellation of contributions from the lower order terms in the DMS so that the accuracy of the computed overtone intensities is mainly limited by the uncertainty of the higher order expansion coefficients in the DMS.

Lin, Hai; Bürger, Hans; MKadmi, El Bachir; He, Sheng-Gui; Yuan, Lan-Feng; Breidung, Jürgen; Thiel, Walter; Huet, Thérèse R.; Demaison, Jean

2001-07-01

131

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

132

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

133

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.

134

Forced Migration Online  

NSDL National Science Digital Library

Designed to function as a comprehensive website that provides access to various resources on forced human migration, this site is provided through the courtesy of the staff at the Refugee Studies Centre at the University of Oxford. While the users of this site will encounter a seamlessly integrated resource, the site contains four separate components. These elements include a searchable digital library, a searchable catalogue with descriptions of and links to Internet-based resources, and a series of geographic and thematic research guides. The homepage offers users access to all of these resources, along with a sidebar that features relevant upcoming events as the International Day of Older Persons. The site also affords visitors access to the full-text of three important publications in the field: Disasters, Forced Migration Review, and International Migration Review (some archived journals are several years behind the current issue). It is worth noting that the homepage also contains a link to a nice introductory essay by Sean Loughna titled "What is Forced Migration?"

135

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.

136

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 Newton’s 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

137

Flood history of the Bavarian Alpine Foreland since the late Middle Ages in the context of internal and external climate forcing factors  

NASA Astrophysics Data System (ADS)

This paper describes the flood history of the Bavarian part of the Alpine Foreland of Germany and addresses different questions concerning climate variability and flood frequencies from the 13th century until today. Will recent climatic change modify the flood frequencies within the Bavarian Alpine Foreland or are the flood frequencies varying due to altering climatic conditions since historical times? In the context of recent discussions whether man-made climate change will modify the present state of flood frequencies, a look back into the past is essential to understand the occurrence of floods in general and of recent floods in particular. In order to understand climatic variability and changes in a comprehensive way, it is necessary to review long time series. A perceived increase of summer floods in eastern Germany and Bavaria since 1997 requires examination of long time series to estimate changes in flood frequencies in a proper way. In view of the annual distribution of flood events within the Alpine Foreland of Germany, summer floods prove to be most important. Based on written historical sources, the flood history of the Alpine Foreland of Germany can be reconstructed back to the 14th century. One major result is the occurrence of "flood-rich" and "flood-poor" episodes in nearly cyclical sequences. Flood-rich periods were recorded in the periods 1300-1335, 1370-1450, 1470-1525, 1555-1590, 1615-1665, 1730-1780, 1820-1870, and 1910-1955 as well as in a 9th period beginning in 1980. The flood-rich periods are characterized by longer flood durations. Most of the flood-rich and flood-poor periods (in particular the beginning and the end of them) can be connected to changes in natural climate variability. These include changing sunspot numbers (as a measure of solar activity), so-called Little Ice Age Type Events (LIATEs) as well as changes in the North Atlantic Oscillation (NAO). Climate signals from external forcing factors, which could be used to explain the changing flood frequencies in the Bavarian Alpine Foreland, end in 1930. Relationships within the climate system such as the correlation of flood frequencies with the NAO have changed during the transition from the post Little Ice Age period to the Modern Climate Optimum around 1930. Natural climate variability might have been outperformed by anthropogenic climate change.

Böhm, O.; Jacobeit, J.; Glaser, R.; Wetzel, K.-F.

2014-07-01

138

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

139

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

140

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

141

Nonequilibrium quantum fluctuation forces  

NASA Astrophysics Data System (ADS)

We study all known and as yet unknown forces between neutral atoms and neutral atoms and surfaces. The forces arise from mutual influences mediated by an attending electromagnetic field and not from direct interaction. We allow as dynamical variables the center of mass motion of the atom (or surface Chapter 5), its internal degrees of freedom, modeled as a three dimensional harmonic oscillator (the internal degrees of freedom of the surface in chapter 4), and the quantum field treated relativistically. We adopt the methods of nonequilibrium quantum field theory (NEqQFT) to study the problem of fluctuation forces beginning from first principles. NEqQFT provides a fully dynamical description of systems far from equilibrium having the advantage of being the synthesis of quantum field theory and nonequilibrium statistical mechanics. The integration of these two paradigms is necessary for a complete study of fluctuation forces; quantum field theory for providing effects such as retardation and quantum field fluctuations, and nonequilbrium statistical mechanics for treating processes involving quantum dissipation and noises. By embarking from first principles we avoid wrong or only partially correct results from inconsistent theories that can be generated from assumptions made at lower levels of accuracy. In thermodynamic equilibrium we reproduce all the effects and forces known in the last century, such as Casimir-Polder---between neutral atoms, Lifshitz---between an atom and a surface and Casimir between surfaces (and the generalization of these forces to nonequilibrium stationary-states). More noteworthy is the discovery of the existence of a new type of interatomic force which we call the 'entanglement force', originating from the quantum correlations of the internal degrees of freedom of entangled atoms. Fluctuation phenomena associated with quantum fields is a new frontier of future research in atom-field interaction. With NEqQFT we have derived Langevin equations which account for fluctuations of an atom's trajectory about its semi-classical value. These quantum field-induced perturbations of the atom's position could lead to measurable results such as the damping of the center-of-mass oscillations of a trapped Bose-Einstein condensate near a surface or backaction cooling of moving mirror by radiative pressure and quantum viscosity discussed respectively in Chapter 3 and 5 of this thesis. The methods introduced in this thesis for treating atom-field interactions or mirror-field interactions go beyond previous work by providing a fully dynamical description of these forces valid for arbitrary atom and surface motion, indeed the inclusion of self-consistent backactions are necessary for the study of phenomena such as quantum decoherence and entanglement dynamics, including non-Markovian processes which invariably will appear when backaction is taken into consideration (especially for strong fields, low temperatures, or fast response).

Behunin, Ryan Orson

142

Force and Motion: Newton's First Law  

NSDL National Science Digital Library

This Science Object is the second of four Science Objects in the Force and Motion SciPack. It provides a conceptual and real-world understanding of Newton's First Law of Motion. All objects will maintain a constant speed and direction of motion unless an unbalanced outside force acts on it. When an unbalanced force acts on an object, its speed or direction (or both) will change. The tendency of objects to maintain a constant speed and direction of motion (velocity) in the absence of an unbalanced force is known as intertia. Even in the most familiar, every day situations, frictional forces can complicate the analysis of motion, although the basic principles still apply. Learning Outcomes:? Recognize and give examples of forces. ? Recognize and give examples of balanced and unbalanced forces.? Equate the term "unbalanced force" with "a net force that does not equal zero."? Apply, in an informal way, Newton's first law. ? Explain the role of the force of friction in determining how well Newton's first law seems to apply or not apply to a given physical situation. ? Explain the reasoning Galileo used to justify the second part of Newton's first law.? Explain how the force of friction applies to the second part of Newton's first law.? Recognize the concept of inertia (as opposed to a force, momentum, etc.). ? Recognize that an object at rest may have forces acting on it.? Distinguish between "impulse" and "sustained" forces (and recognize both).? Recognize that objects do not have internal forces that keep them moving.

National Science Teachers Association (NSTA)

2006-01-01

143

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

144

Estimation of Coriolis Force and Torque Acting on Ares-1  

NASA Technical Reports Server (NTRS)

A document describes work on the origin of Coriolis force and estimating Coriolis force and torque applied to the Ares-1 vehicle during its ascent, based on an internal ballistics model for a multi-segmented solid rocket booster (SRB).

Mackey, Ryan M.; Kulikov, Igor K.; Smelyanskiy, Vadim; Luchinsky, Dmitry; Orr, Jeb

2011-01-01

145

International Responses to Territorial Conquest  

Microsoft Academic Search

The prohibition on territorial conquest is a cornerstone of the international legal order. The United Nations Charter bans the use of force as a tool of international relations, even when used to rectify prior injustices. Thus territory taken by force has the status of ill-gotten gains, and cannot be kept by the victor. An important corollary is that third-party states

Eugene Kontorovich

2009-01-01

146

The thermohaline forcing of the Gibraltar exchange  

Microsoft Academic Search

A conceptual framework for understanding the exchange through Gibraltar and its thermohaline forcing is presented. The Mediterranean Sea annually produces a dense water mass that sinks and accumulates above the level of the sill until the internal pressure gradient generated through the Strait is sufficiently strong to force it out at a rate equal to the rate of its mean

Tom Sawyer Hopkins

1999-01-01

147

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

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

2011-01-01

148

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

149

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.

150

Future Force and First Responders: Building Ties for Collaboration and  

E-print Network

for collaboration between Military Forces and First Responders · e.g., response to terrorist attacks, internationalFuture Force and First Responders: Building Ties for Collaboration and Leveraged R&D Joachim Hammer peacekeeping roles · First Responders (FR) and Future Force warriors (FF) have similar information needs

Hammer, Joachim

151

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

Federal Register 2010, 2011, 2012, 2013, 2014

...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

152

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

Federal Register 2010, 2011, 2012, 2013, 2014

...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

153

The future of general internal medicine  

Microsoft Academic Search

The Society of General Internal Medicine asked a task force to redefine the domain of general internal medicine. The task\\u000a force believes that the chaos and dysfunction that characterize today’s medical care, and the challenges facing general internal\\u000a medicine, should spur innovation. These are our recommendations: while remaining true to its core values and competencies,\\u000a general internal medicine should stay

Eric B. Larson; Stephan D. Fihn; Lynne M. Kirk; Wendy Levinson; Ronald V. Loge; Eileen Reynolds; Lewis Sandy; Steven Schroeder; Neil Wenger; Mark Williams

2004-01-01

154

Force and Its Representation  

NSDL National Science Digital Library

This page is from a comprehensive and comprehensible tutorial in physics. Schematic drawings, animations, and links to animations are included. Use the link in the left navigation bar to explore the related topic of types of forces including frictional force, gravitational force, and magnetic force.

2010-01-01

155

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; Höfinger, Siegfried

2013-01-01

156

International Flavor International Dentist  

E-print Network

International Flavor International Dentist Program in its Fifth Year Dean Bertolami Celebrates, International Dentist Program Richard McKenzie, Director of Development & Alumni Relations Dorothy A. Perry this issue... for alumni: profileBACK COVER For Leo Boger (D'65), a dentist in San Jose, giving back

Klein, Ophir

157

Evaluation of Intern Intern's Name ____________________________________________________  

E-print Network

Evaluation of Intern Intern's Name ____________________________________________________ Quarter ____________________________________________________ ____________________________________________________ Please complete this evaluation, commenting on the following aspects of the intern and the internship program. After completion please review the evaluation with the intern. The intern will not receive

California at Santa Barbara, University of

158

Physicists' Forced Migrations under Hitler  

NASA Astrophysics Data System (ADS)

When the Nazis came to power in early 1933 they initiated formal and informal measures that forced Jews and political opponents from public institutions such as universities. Some physicists retired and others went into industry, but most emigrated. International communication and contact made emigration a viable option despite the desperate economic times in the Great Depression. Another wave of emigrations followed the annexation of Austria in 1938. Individual cases as well as general patterns of migration and adaptation to new environments will be examined in this presentation. One important result of the forced migrations was that many of the physicists expelled under Hitler played important roles in strengthening physics elsewhere, often on the Allied side in World War II.

Beyerchen, Alan

2011-03-01

159

Screened Casimir forces  

SciTech Connect

We demonstrate that a very recently obtained formula for the force on a slab in a material planar cavity based on the calculation of the vacuum Lorentz force [C. Raabe and D.-G. Welsch, Phys. Rev. A 71, 013814 (2005)] describes a (medium) modified Casimir force and, in addition to it, a medium-assisted force. The latter force also describes the force on the cavity medium. For dilute media, it implies the atom-mirror interaction of the Casimir-Polder type at large and of the Coulomb type at small atom-mirror distances of which the sign is insensitive to the polarizability type (electric or magnetic) of the atom.

Tomas, M.S. [Rudjer Boskovic Institute, P. O. B. 180, 10002 Zagreb (Croatia)

2005-06-15

160

Repulsive Casimir Forces  

NASA Astrophysics Data System (ADS)

We discuss repulsive Casimir forces between dielectric materials with nontrivial magnetic susceptibility. It is shown that considerations based on the naive pairwise summation of van der Waals and Casimir-Polder forces may not only give an incorrect estimate of the magnitude of the total Casimir force but even the wrong sign of the force when materials with high dielectric and magnetic responses are involved. Indeed repulsive Casimir forces may be found in a large range of parameters, and we suggest that the effect may be realized in known materials. The phenomenon of repulsive Casimir forces may be of importance both for experimental study and for nanomachinery applications.

Kenneth, O.; Klich, I.; Mann, A.; Revzen, M.

2002-06-01

161

Screened Casimir forces  

NASA Astrophysics Data System (ADS)

We demonstrate that a very recently obtained formula for the force on a slab in a material planar cavity based on the calculation of the vacuum Lorentz force [C. Raabe and D.-G. Welsch, Phys. Rev. A 71, 013814 (2005)] describes a (medium) modified Casimir force and, in addition to it, a medium-assisted force. The latter force also describes the force on the cavity medium. For dilute media, it implies the atom-mirror interaction of the Casimir-Polder type at large and of the Coulomb type at small atom-mirror distances of which the sign is insensitive to the polarizability type (electric or magnetic) of the atom.

Tomaš, M. S.

2005-06-01

162

International Seminar, "Explaining major shifts in policing, an international perspective"  

E-print Network

forces have started an identity transition based on principles borrowed from the community policingInternational Seminar, "Explaining major shifts in policing, an international perspective" June, 29 th 2007 Local security policies in Italy: new key institutional players, transformation of policing

Paris-Sud XI, Université de

163

Quarkonium Binding and Entropic Force  

E-print Network

A Q-Qbar bound state represents a balance between repulsive kinetic and attractive potential energy. In a hot quark-gluon plasma, the interaction potential experiences medium effects. Color screening modifies the attractive binding force between the quarks, while the increase of entropy with Q-Qbar separation gives rise to a growing repulsion. We study the role of these phenomena for in-medium Q-Qbar binding and dissociation. It is found that the relevant potential for Q-Qbar binding is the free energy F; with increasing Q-Qbar separation, further binding through the internal energy U is compensated by repulsive entropic effects.

Helmut Satz

2015-01-20

164

Quarkonium Binding and Entropic Force  

E-print Network

A Q-Qbar bound state represents a balance between repulsive kinetic and attractive potential energy. In a hot quark-gluon plasma, the interaction potential experiences medium effects. Color screening modifies the attractive binding force between the quarks, while the increase of entropy with Q-Qbar separation gives rise to a growing repulsion. We study the role of these phenomena for in-medium Q-Qbar binding and dissociation. It is found that the relevant potential for Q-Qbar binding is the free energy F; with increasing Q-Qbar separation, further binding through the internal energy U is compensated by repulsive entropic effects.

Satz, Helmut

2015-01-01

165

Citizen groups: a creative force  

SciTech Connect

The role of citizen groups is as important as that of government agencies when it comes to environmental policy in a democracy. These groups spend little money, yet they have initiated the major US environmental legislation of the past two decades. They are a recent, but effective, force in developing countries even though adversarial approaches are not often appropriate. The methods used by US environmental groups range from lobbying to confrontation in court. Groups outside the US tend to use consensus in democracies and information gathering in developing countries. While the groups' primary concerns are national in scope, international awareness and cooperation are growing. (DCK)

Stoel, T.

1981-02-01

166

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.

John Nielsen-Gammon

1996-01-01

167

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.

168

Aerodynamic Lifting Force.  

ERIC Educational Resources Information Center

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

Weltner, Klaus

1990-01-01

169

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

170

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

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; Caubère, 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; Zaïm, M; Zetlaoui, J; Vellas, B

2013-07-01

171

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

172

Fluid force transducer  

DOEpatents

An electrical fluid force transducer for measuring the magnitude and direction of fluid forces caused by lateral fluid flow, includes a movable sleeve which is deflectable in response to the movement of fluid, and a rod fixed to the sleeve to translate forces applied to the sleeve to strain gauges attached to the rod, the strain gauges being connected in a bridge circuit arrangement enabling generation of a signal output indicative of the magnitude and direction of the force applied to the sleeve.

Jendrzejczyk, Joseph A. (Warrenville, IL)

1982-01-01

173

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

174

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

Code of Federal Regulations, 2013 CFR

...group), International Service Agencies and the military aid societies. (5) When Armed Forces participation in an event is in the...three days. (8) Armed Forces participation in professional sports events and post-season bowl games will normally be...

2013-07-01

175

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

Code of Federal Regulations, 2011 CFR

...group), International Service Agencies and the military aid societies. (5) When Armed Forces participation in an event is in the...three days. (8) Armed Forces participation in professional sports events and post-season bowl games will normally be...

2011-07-01

176

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

Code of Federal Regulations, 2012 CFR

...group), International Service Agencies and the military aid societies. (5) When Armed Forces participation in an event is in the...three days. (8) Armed Forces participation in professional sports events and post-season bowl games will normally be...

2012-07-01

177

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

Code of Federal Regulations, 2014 CFR

...group), International Service Agencies and the military aid societies. (5) When Armed Forces participation in an event is in the...three days. (8) Armed Forces participation in professional sports events and post-season bowl games will normally be...

2014-07-01

178

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

179

The task force process  

Microsoft Academic Search

This paper focuses on the unique aspects of the Fernald Citizens Task Force process that have contributed to a largely successful public participation effort at Fernald. The Fernald Citizens Task Force passed quickly by many procedural issues. Instead, the Task Force concentrated on (a) educating itself about the site, its problems, and possible solutions, and (b) choosing a directed way

Applegate

1995-01-01

180

Turkish Students' Force Meanings  

ERIC Educational Resources Information Center

What are Turkish pre, elementary, middle, and high school students' force ideas? And, how do Turkish students' non-normative force ideas differ or be similar to the well-known force misconceptions reported in the literature? Students have false and persistent beliefs about the physical world and they struggle with challenging misconceptions based…

Menekse, Muhsin; Clark, Douglas B.; Ozdemir, Gokhan; D'angelo, Cynthia; Scheligh, Sharon

2009-01-01

181

Debunking Coriolis Force Myths  

ERIC Educational Resources Information Center

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

Shakur, Asif

2014-01-01

182

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

183

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

184

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

185

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

186

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...

187

Cell adhesion force microscopy  

PubMed Central

The adhesion forces of cervical carcinoma cells in tissue culture were measured by using the manipulation force microscope, a novel atomic force microscope. The forces were studied as a function of time and temperature for cells cultured on hydrophilic and hydrophobic polystyrene substrates with preadsorbed proteins. The cells attached faster and stronger at 37°C than at 23°C and better on hydrophilic than on hydrophobic substrates, even though proteins adsorb much better to the hydrophobic substrates. Because cell adhesion serves to control several stages in the cell cycle, we anticipate that the manipulation force microscope can help clarify some cell-adhesion related issues. PMID:9892657

Sagvolden, G.; Giaever, I.; Pettersen, E. O.; Feder, J.

1999-01-01

188

Forces in molecules.  

PubMed

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

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

2007-01-01

189

Force Limited Vibration Testing  

NASA Technical Reports Server (NTRS)

This slide presentation reviews the concept and applications of Force Limited Vibration Testing. The goal of vibration testing of aerospace hardware is to identify problems that would result in flight failures. The commonly used aerospace vibration tests uses artificially high shaker forces and responses at the resonance frequencies of the test item. It has become common to limit the acceleration responses in the test to those predicted for the flight. This requires an analysis of the acceleration response, and requires placing accelerometers on the test item. With the advent of piezoelectric gages it has become possible to improve vibration testing. The basic equations have are reviewed. Force limits are analogous and complementary to the acceleration specifications used in conventional vibration testing. Just as the acceleration specification is the frequency spectrum envelope of the in-flight acceleration at the interface between the test item and flight mounting structure, the force limit is the envelope of the in-flight force at the interface . In force limited vibration tests, both the acceleration and force specifications are needed, and the force specification is generally based on and proportional to the acceleration specification. Therefore, force limiting does not compensate for errors in the development of the acceleration specification, e.g., too much conservatism or the lack thereof. These errors will carry over into the force specification. Since in-flight vibratory force data are scarce, force limits are often derived from coupled system analyses and impedance information obtained from measurements or finite element models (FEM). Fortunately, data on the interface forces between systems and components are now available from system acoustic and vibration tests of development test models and from a few flight experiments. Semi-empirical methods of predicting force limits are currently being developed on the basis of the limited flight and system test data. A simple two degree of freedom system is shown and the governing equations for basic force limiting results for this system are reviewed. The design and results of the shuttle vibration forces (SVF) experiments are reviewed. The Advanced Composition Explorer (ACE) also was used to validate force limiting. Test instrumentation and supporting equipment are reviewed including piezo-electric force transducers, signal processing and conditioning systems, test fixtures, and vibration controller systems. Several examples of force limited vibration testing are presented with some results.

Scharton, Terry; Chang, Kurng Y.

2005-01-01

190

Internal object loading for multiple cooperating robot manipulators  

Microsoft Academic Search

For an object being rigidly grasped and manipulated by multiple robotic mechanisms, the internal loading characteristics at a common coordinate set within the object are considered. It is demonstrated that representation of internal forces and moments in these common coordinates give insight into force and load distribution schemes developed previously. In particular, it is shown how internal loads may be

Ian D. Walker; Robert A. Freeman; Steven I. Marcus

1989-01-01

191

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

192

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

193

Analysis and experimental validation of force bandwidth for force control  

Microsoft Academic Search

Controlling robots in contact with the environment is an important problem in industry applications. In the conventional force control, much research has paid attention to develop novel force control systems and implemented force sensors to detect external force. This paper shows that narrow bandwidth of force sensor has a big influence on the force control system. Generally, to solve the

Seiichiro Katsura; Yuichi Matsumoto; Kouhei Ohnishi

2006-01-01

194

Forces exerted during microneurosurgery: a cadaver study  

PubMed Central

Background A prerequisite for the successful design and use of robots in neurosurgery is knowledge of the forces exerted by surgeons during neurosurgical procedures. The aim of the present cadaver study was to measure the surgical instrument forces exerted during microneurosurgery. Methods An experimental apparatus was set up consisting of a platform for human cadaver brains, a Leica microscope to provide illumination and magnification, and a Quanser 6 Degrees-Of-Freedom Telepresence System for tissue manipulation and force measurements. Results The measured forces varied significantly depending on the region of the brain (P?=?0.016) and the maneuver performed (P?force exertion than sharp dissection (0.22?N vs. 0.03?N; P?=?0.001). Conclusions The forces necessary to manipulate brain tissue were surprisingly low and varied depending on the anatomical structure being manipulated, and the maneuver performed. Knowledge of such forces could well increase the safety of microsurgery. © 2014 The Authors. The International Journal of Medical Robotics and Computer Assisted Surgery published by John Wiley & Sons, Ltd. PMID:24431265

Marcus, Hani J; Zareinia, Kourosh; Gan, Liu Shi; Yang, Fang Wei; Lama, Sanju; Yang, Guang-Zhong; Sutherland, Garnette R

2014-01-01

195

Weapons of Mass Destruction & Public International Law  

Microsoft Academic Search

The proliferation of weapons of mass destruction (WMD) into the hands of rogue dictators and terrorists has brought a sea change in strategic international relations, and is accelerating the necessity of public international law to protect humanity. Traditional balances of power have little force left to deter WMD. Major powers must seriously revamp and proactively exploit public international law, and,

Michael Donlan

2005-01-01

196

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.

197

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

198

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

199

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

200

Three-body forces  

SciTech Connect

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

Friar, J.L.

1982-01-01

201

Physlet Force Concept Inventory: Gravity and Force  

NSDL National Science Digital Library

The accompanying animation shows a frictionless channel in the shape of a segment of circle with center at "O". The channel has been anchored to a frictionless horizontal table top. Forces exerted by the air are negligible. A ball is shot at high speeds into the channel at "p" and exits at "r".

Wolfgang Christian

202

Modal analysis of rotor-shaft system under the influence of rotor-shaft material damping and fluid film forces  

Microsoft Academic Search

The present work attempts to study the influences of internal rotor material damping and the fluid film forces (generated as a result of hydrodynamic action in journal bearings) on the modal behaviour of a flexible rotor-shaft system. This is relevant as both journal bearing and the internal material damping introduce tangential forces increasing with the rotor spin speed. Such forces

M. Chouksey; J. K. Dutt; S. V. Modak

203

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

204

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, Stéphane P; Abellán Flos, Marta; Hols, Pascal; Lipke, Peter N; Dufrêne, Yves F

2015-02-01

205

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

John Haysom

2010-10-01

206

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

207

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, Stéphane P.; Abellán Flos, Marta; Hols, Pascal; Lipke, Peter N.; Dufrêne, Yves F.

2015-01-01

208

Deriving force from inductance  

Microsoft Academic Search

The correctness of calculating the force on current carrying circuits by taking the derivative of the inductance coefficient of the circuits is shown even in the case of a single closed circuit, contrary to the opinion of some authors. This demonstration is illustrated with the force exerted by a cylinder with poloidal current on an infinitesimal strip belonging to the

M. de Almeida Bueno; A. K. T. Assis

1998-01-01

209

International development  

E-print Network

place alongside political and social upheavals provoking intense debate about the nature of poverty, inequality, development and aid at local, national and international levels. Studying international to reducing poverty and inequality. Essentials Courses BA (Hons) in International Development BA (Hons

Sussex, University of

210

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

211

Dynamic Force Generation by Neural Stem Cells  

PubMed Central

Mechanical cues may have important roles in tissue morphogenesis; progression through complex functions like differentiation may be associated with changes in cellular force generation and mechanosensing. To explore this concept, we use elastomer pillar arrays to map forces generated by neural stem cells in vitro, and identify two distinct dynamics of force generation. First, cell generated forces decrease as cells transition from a proliferative mode to differentiation, a process covering several days. This change in force generation correlated with a loss of sensitivity to substrate rigidity over a series of polydimethylsiloxane substrates. Second, neural stem cells exhibit a faster pattern of localized contractions at the cell body and outlying processes; each lasts on the order of minutes, and is not synchronized across the cell. This faster process is reminiscent of migratory behavior observed in vivo, and may be involved in controlling the motion of internal structures such as the cell nucleus. These results together provide new clues into the role of forces during development, and may lead to design principles for materials targeted for use in the central nervous system. PMID:20401168

Shi, P.; Shen, K.; Ghassemi, S.; Hone, J.; Kam, L.C.

2010-01-01

212

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

213

OOTW Force Design Tools  

SciTech Connect

This report documents refined requirements for tools to aid the process of force design in Operations Other Than War (OOTWs). It recommends actions for the creation of one tool and work on other tools relating to mission planning. It also identifies the governmental agencies and commands with interests in each tool, from whom should come the user advisory groups overseeing the respective tool development activities. The understanding of OOTWs and their analytical support requirements has matured to the point where action can be taken in three areas: force design, collaborative analysis, and impact analysis. While the nature of the action and the length of time before complete results can be expected depends on the area, in each case the action should begin immediately. Force design for OOTWs is not a technically difficult process. Like force design for combat operations, it is a process of matching the capabilities of forces against the specified and implied tasks of the operation, considering the constraints of logistics, transport and force availabilities. However, there is a critical difference that restricts the usefulness of combat force design tools for OOTWs: the combat tools are built to infer non-combat capability requirements from combat capability requirements and cannot reverse the direction of the inference, as is required for OOTWs. Recently, OOTWs have played a larger role in force assessment, system effectiveness and tradeoff analysis, and concept and doctrine development and analysis. In the first Quadrennial Defense Review (QDR), each of the Services created its own OOTW force design tool. Unfortunately, the tools address different parts of the problem and do not coordinate the use of competing capabilities. These tools satisfied the immediate requirements of the QDR, but do not provide a long-term cost-effective solution.

Bell, R.E.; Hartley, D.S.III; Packard, S.L.

1999-05-01

214

Mapping nonlinear forces with congruent vibration functions  

NASA Astrophysics Data System (ADS)

This paper considers a new nonparametric identification method for vibration systems. The novelty of the identification is that an unknown arbitrary internal force not separated for stiffness and damping is assumed a priori. A nonlinear vibration structure is decomposed in a number of subsystems, each with its own vibration frequency solution, amplitude and phase as functions of time. Multiple frequency components included in the solution composition can be uncovered by the Hilbert vibration decomposition and subsequent congruent aggregation. The unknown internal acting force is estimated by the displacement-acceleration phase angle and the special partial analytical methods. The developed identification methods were successfully applied to a simulated signal obtained from different nonlinear vibration models, among them the Duffing model, dry friction, combined nonlinearities in backlash stiffness with turbulent quadratic damping, and the van der Pol oscillator.

Feldman, M.

2013-05-01

215

Forced Migration Projects  

NSDL National Science Digital Library

The Forced Migration Projects (FMP), operating under the auspices of the Open Society Institute (OSI), monitor developments in the Americas, the former Yugoslavia, and the former Soviet Union to identify the social, political, and economic conditions that cause the forced dislocations of people. This Website provides background information about the projects as well as full-text access to several FMP publications including The Forced Migration Monitor, a series of special reports on refugees and migration, recent news and articles on germane issues, and FM Alert, an electronic bulletin service. In addition, the site compiles a list of refugee-related links and hosts a discussion forum.

216

International Cooperation at NASA  

NASA Astrophysics Data System (ADS)

International cooperation is a cornerstone principle of NASA’s 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 NASA’s 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

217

Trends of measured climate forcing agents  

PubMed Central

The growth rate of climate forcing by measured greenhouse gases peaked near 1980 at almost 5 W/m2 per century. This growth rate has since declined to ?3 W/m2 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 (?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. PMID:11752424

Hansen, James E.; Sato, Makiko

2001-01-01

218

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

219

Forces in Motion.  

ERIC Educational Resources Information Center

Describes an activity to give students experience with the variables and forces impacting a moving body on an inclined plane by observing a ball as it rolls down an inclined PVC pipe of fixed length. Includes a student worksheet. (MKR)

Goodsell, David; And Others

1995-01-01

220

Causal reasoning with forces.  

PubMed

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

221

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

222

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

223

Task Force on Information  

E-print Network

impact the University's goals and day-to-day operations. Our technological infrastructure must provide Task Force on Information Technology Recommendations September 16 2013 ITS will be a dynamic, agile organization, committed to reliable service, clear communication

Suzuki, Masatsugu

224

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

225

Depletion forces in nonequilibrium.  

PubMed

The concept of effective depletion forces between two fixed big colloidal particles in a bath of small particles is generalized to a nonequilibrium situation where the bath of small Brownian particles is flowing around the big particles with a prescribed velocity. In striking contrast to the equilibrium case, the nonequilibrium forces violate Newton's third law; they are nonconservative and strongly anisotropic, featuring both strong attractive and repulsive domains. PMID:14683160

Dzubiella, J; Löwen, H; Likos, C N

2003-12-12

226

Force-Measuring Clamp  

NASA Technical Reports Server (NTRS)

A precision clamp that accurately measures force over a wide range of conditions is described. Using a full bridge or other strain gage configuration. the elastic deformation of the clamp is measured or detected by the strain gages. Thc strain gages transmit a signal that corresponds to the degree of stress upon the clamp. Thc strain gage signal is converted to a numeric display. Calibration is achieved by ero and span potentiometers which enable accurate measurements by the force-measuring clamp.

Nunnelee, Mark (Inventor)

2004-01-01

227

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

228

The missing climate forcing  

PubMed Central

Observed climate change is consistent with radiative forcings on several time-scales for which the dominant forcings are known, ranging from the few years after a large volcanic eruption to glacial-to-interglacial changes. In the period with most detailed data, 1979 to the present, climate observations contain clear signatures of both natural and anthropogenic forcings. But in the full period since the industrial revolution began, global warming is only about half of that expected due to the principal forcing, increasing greenhouse gases. The direct radiative effect of anthropogenic aerosols contributes only little towards resolving this discrepancy. Unforced climate variability is an unlikely explanation. We argue on the basis of several lines of indirect evidence that aerosol effects on clouds have caused a large negative forcing, at least -1 Wm-2, which has substantially offset greenhouse warming. The tasks of observing this forcing and determining the microphysical mechanisms at its basis are exceptionally difficult, but they are essential for the prognosis of future climate change.

Hansen, J.; Sato, M.; Lacis, A.; Ruedy, R.

1997-01-01

229

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

230

Measurements of human force control during a constrained arm motion using a force-actuated joystick.  

PubMed

1. When interacting with the environment, human arm movements may be prevented in certain directions (i.e., when sliding the hand along a surface) resulting in what is called a "constrained motion." In the directions that the movement is restricted, the subject is instead free to control the forces against the constraint. 2. Control strategies for constrained motion may be characterized by two extreme models. Under the active compliance model, an essentially feedback-based approach, measurements of contact force may be used in real time to modify the motor command and precisely control the forces generated against the constraint. Under the passive compliance model the motion would be executed in a feedforward manner, using an internal model of the constraint geometry. The feedforward model relies on the compliant behavior of the passive mechanical system to maintain contact while avoiding excessive contact forces. 3. Subjects performed a task in which they were required to slide the hand along a rigid surface. This task was performed in a virtual force environment in which contact forces were simulated by a two-dimensional force-actuated joystick. Unknown to the subject, the orientation of the surface constraint was varied from trial to trial, and contact force changes induced by these perturbations were measured. 4. Subjects showed variations in contact force correlated with the direction of the orientation perturbation. "Upward" tilts resulted in higher contact forces, whereas "downward" tilts resulted in lower contact forces. This result is consistent with a feedforward-based control of a passively compliant system. 5. Subject responses did not, however, correspond exactly to the predictions of a static analysis of a passive, feedforward-controlled system. A dynamic analysis reveals a much closer resemblance between a passive, feedforward model and the observed data. Numerical simulations demonstrate that a passive, dynamic system model of the movement captures many more of the salient features observed in the measured human data. 6. We conclude that human subjects execute surface-following motions in a largely feedforward manner, using an a priori model of the surface geometry. The evidence does not suggest that active, real time use of force feedback is used to guide the movement or to control limb impedance. We do not exclude, however, the possibility that the internal model of the constraint is updated at somewhat longer latencies on the basis of proprioceptive information. PMID:7608766

McIntyre, J; Gurfinkel, E V; Lipshits, M I; Droulez, J; Gurfinkel, V S

1995-03-01

231

Lenz's Law: Feel the Force.  

ERIC Educational Resources Information Center

Describes a simple, inexpensive system that allows students to have hands-on contact with simple experiments involving forces generated by induced currents. Discusses the use of a dynamic force sensor in making quantitative measurements of the forces generated. (JRH)

Sawicki, Charles A.

1996-01-01

232

Uptake and use of recommendations for the diagnosis, severity scoring and management of chronic graft-versus-host disease: An international survey of the EBMT-NCI Chronic GVHD Task Force  

PubMed Central

In 2005, the NIH consensus conference published a series of papers recommending methods to improve the conduct of clinical trials in chronic graft-versus-host disease (GVHD). Although the NIH recommendations were primarily aimed at strengthening research, several papers addressed issues relevant for clinical practice, particularly diagnosis, severity scoring, and ancillary and supportive care practices. We conducted an international survey to assess the uptake of these recommendations, identify barriers to greater use, and document the use and perceived effectiveness of available treatments. The response rate for the American survey of 1,387 practitioners was 21.8%, and it was 24.6% for 407 centers surveyed in Europe, Asia, Australia and Africa. Most respondents were familiar with the NIH consensus recommendations (94-96%) and used them in practice. Multiple barriers to greater use were reported. Besides lack of time (55-62%), unfamiliarity with the recommendations, scarcity of evidence supporting the impact of recommendations on outcomes, insufficient training/experience in chronic GVHD management, and inaccessibility of subspecialists were also endorsed. Systemic corticosteroids were reported to be the most effective treatment for chronic GVHD, but many others were perceived to have moderate or great success. Therapeutic management of steroid-refractory chronic GVHD was identified as the highest priority for research. PMID:23955633

Duarte, Rafael F.; Greinix, Hildegard; Rabin, Borsika; Mitchell, Sandra A.; Basak, Grzegorz; Wolff, Daniel; Madrigal, J. Alejandro; Pavletic, Steven Z.; Lee., Stephanie J.

2013-01-01

233

MU INTERNATIONAL DIRECTORY International Directory  

E-print Network

1 MU INTERNATIONAL DIRECTORY International Directory Below you will find contact information for the numerous offices across campus that contribute to MU's international initiatives. This directory is constantly revised and edited. For the most current information please visit http://international.missouri.edu/directory

Taylor, Jerry

234

International Tax as International Law  

Microsoft Academic Search

The purpose of this article is to introduce to the international lawyer the somewhat different set of categories (e.g., residence and source rather than nationality and territoriality) employed by international tax lawyers, and explain the reasons for some of the differences. At the same time, it attempts to persuade practicing international tax lawyers and international tax academics that their field

Reuven S. Avi-Yonah

2004-01-01

235

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

2013-05-30

236

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

237

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

238

Carbohydrate force fields  

PubMed Central

Carbohydrates present a special set of challenges to the generation of force fields. First, the tertiary structures of monosaccharides are complex merely by virtue of their exceptionally high number of chiral centers. In addition, their electronic characteristics lead to molecular geometries and electrostatic landscapes that can be challenging to predict and model. The monosaccharide units can also interconnect in many ways, resulting in a large number of possible oligosaccharides and polysaccharides, both linear and branched. These larger structures contain a number of rotatable bonds, meaning they potentially sample an enormous conformational space. This article briefly reviews the history of carbohydrate force fields, examining and comparing their challenges, forms, philosophies, and development strategies. Then it presents a survey of recent uses of these force fields, noting trends, strengths, deficiencies, and possible directions for future expansion. PMID:25530813

Foley, B. Lachele; Tessier, Matthew B.; Woods, Robert J.

2014-01-01

239

Balkans Task Force  

NSDL National Science Digital Library

UNEP, the United Nations Environment Programme, launched the Balkans Task Force (BTF) Website on May 5, 1999 to provide information and updates on "the environmental and human settlements impacts of the ongoing Balkans conflict." Experts from the Balkans Task Force visit war-damaged (industrial) sites and post their results in a series of online Situation Reports; currently, fourteen reports (in HTML or .pdf) are available on-site. Also provided are regional maps, general information, related news and documents, and a series of links to other Websites featuring aspects of the Kosovo conflict.

240

Optical force stamping lithography.  

PubMed

Here we introduce a new paradigm of far-field optical lithography, optical force stamping lithography. The approach employs optical forces exerted by a spatially modulated light field on colloidal nanoparticles to rapidly stamp large arbitrary patterns comprised of single nanoparticles onto a substrate with a single-nanoparticle positioning accuracy well beyond the diffraction limit. Because the process is all-optical, the stamping pattern can be changed almost instantly and there is no constraint on the type of nanoparticle or substrates used. PMID:21992538

Nedev, Spas; Urban, Alexander S; Lutich, Andrey A; Feldmann, Jochen

2011-11-01

241

Forces and Graphing  

NSDL National Science Digital Library

Use this activity to explore forces acting on objects, practice graphing experimental data, and introduce the algebra concepts of slope and intercept of a line. A wooden 2 x 4 beam is set on top of two scales. Students learn how to conduct an experiment by applying loads at different locations along the beam, recording the exact position of the applied load and the reaction forces measured by the scales at each end of the beam. In addition, students analyze the experiment data with the use of a chart and a table, and model/graph linear equations to describe relationships between independent and dependent variables.

GK-12 Program, Center for Engineering and Computing Education, College of Engineering and Information Technology,

242

Dynamically Forced Fog  

NSDL National Science Digital Library

Fog frequently forms in response to dynamically forced changes in the boundary layer. This module examines dynamically forced fog in the coastal and marine environment, focusing on advection fog, steam fog, and west coast type fog. The focus of the module is on the boundary layer evolution of air parcels as they traverse trajectories over land and water. The module also examines mesoscale effects that impact the distribution of fog and low-level stratus over short distances. A general discussion of forecast products and methodologies concludes the module.

COMET

2005-03-01

243

Academic Affairs and International Programs  

E-print Network

Academic Affairs and International Programs Vice Provost Rebecca L. Johnson September 2006 ROTC Air Vicki Tolar Burton CAMP Program Director AmasAduviri OSU Libraries UniversityLibrarian Karyle S. Butcher Force Studies Commander Douglas R. Cochran Military Science Commander Michael J. Daniels Naval Science

Escher, Christine

244

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

245

International reputation  

E-print Network

at Illinois n african studies n east asian studies n european Union studies n Global studies n International, east european, and eurasian studies additional programs in International Programs and studies n and Gender in Global Perspectives Program International enrollment by top five colleges 0 500 1000 1500 2000

Anastasio, Thomas J.

246

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

2013-05-30

247

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

248

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.

249

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.

250

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

251

Brane -Antibrane Forces  

Microsoft Academic Search

The force between like sign BPS saturated objects generally vanishes. This is a reflection of the fact that BPS states are really massless uncharged particles with nonvanishing momenta in compactified directions. Two like sign BPS ob- jects with zero relative velocity can be viewed as a boosted state of two neutral massless particles in a state of vanishing relative motion.

Tom Banks; Leonard Susskind

252

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

253

Optically induced 'negative forces'  

NASA Astrophysics Data System (ADS)

Attracting objects with optical beams may seem like science fiction, but various schemes already do this, albeit with some caveats and limitations. The most recent progress in this emerging field is reviewed, with particular emphasis on manipulation of small objects by optically induced 'negative forces'.

Dogariu, Aristide; Sukhov, Sergey; Sáenz, José

2013-01-01

254

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

255

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

256

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

257

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

258

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

259

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

260

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

261

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.

262

Casimir force between topological insulator slabs  

NASA Astrophysics Data System (ADS)

The Casimir force between two finite-thick topological insulator slabs and its dependence on the gap size between the slabs are investigated in detail. Two typical substrate materials including semi-infinite vacuum and silicon are used in the study, in which the Casimir force can always change from attractive to repulsive when the gap size decreases. The gap width at transition is a function of the slab thickness and also depends strongly on the electric permittivity and topological magnetoelectric polarizability of the slabs. In particular, in the absence of a substrate, this width increases with decreasing slab thickness and for thin slabs with large internal and external topological magnetoelectric polarizability the Casimir force is always repulsive where the surface topological magnetoelectric effect of the slabs plays a dominant role. In the presence of a semi-infinite silicon substrate, however, the attractive role of the silicon substrate becomes increasingly important, and thus the transition gap decreases with decreasing thickness of the slab. The characteristic features of the Casimir force may be detected experimentally through exploring its gradient with a certain dynamical method.

Nie, Wenjie; Zeng, Ran; Lan, Yueheng; Zhu, Shiyao

2013-08-01

263

Suicide and Forced Marriage  

PubMed Central

Background: The prevailing view that the vast majority of those who complete suicide have an underlying psychiatric disorder has been recently challenged by research on the contribution of “predicaments”, in the absence of mental illness, to suicide. In this paper, we sought data to support the notion that forced marriage may lead to suicide without the presence of psychiatric disorder. Methods: Historical records, newspapers, and the electronic media were searched for examples. Results: Two examples from ancient times and six from the last hundred years were located and described. Conclusion: These cases suggest that forced marriage may lead to suicide and complements earlier findings that loss of fortune, health, liberty, and reputation may lead to suicide in the absence of mental disorder. PMID:23983577

Pridmore, Saxby; Walter, Garry

2013-01-01

264

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

265

Bushmeat Crisis Task Force  

NSDL National Science Digital Library

This Web site is the homepage of the Bushmeat Crisis Task Force (BCTF), a nonprofit organization that works toward "identifying and implementing effective and appropriate solutions to the commercial exploitation of endangered and threatened species." In addition to providing information on BCTF projects and upcoming events, the Web site offers a comprehensive collection of articles meant to raise awareness of the bushmeat crisis, as well as a number of fact sheets, each covering a specific aspect of the bushmeat trade.

266

Vector Piezoresponse Force Microscopy  

Microsoft Academic Search

A novel approach for nanoscale imaging and characterization of the orientation dependence of electromechanical properties---vector piezoresponse force microscopy (Vector PFM)---is described. The relationship between local electromechanical response, polarization, piezoelectric constants, and crystallographic orientation is analyzed in detail. The image formation mechanism in vector PFM is discussed. Conditions for complete three-dimensional (3D) reconstruction of the electromechanical response vector and evaluation of

Sergei V. Kalinin; Brian J. Rodriguez; Stephen Jesse; Junsoo Shin; Arthur P. Baddorf; Pradyumna Gupta; Himanshu Jain; David B. Williams; Alexei Gruverman

2006-01-01

267

Indirect Force Control  

Microsoft Academic Search

\\u000a The potential offered by motion control strategies to ensure a compliant behavior during the interaction between the end effector\\u000a and the environment is investigated. Compliance control and impedance control are introduced as effective tools to achieve\\u000a indirect control of the contact force. An inner motion loop is adopted to enhance disturbance rejection. Six-DOF impedance\\u000a control schemes are derived using different

Bruno Siciliano; Luigi Villani

268

Impact and force control  

Microsoft Academic Search

Robot manipulators and drive systems can experience instability or poor control performance after impacting with an environment. The authors present an analytical model for impact which is experimentally validated step-by-step. Extensive simulations and experiments are conducted to explain impact phenomena for the case of a force feedback control of a single-axis drive system. The experimental tests were conducted on a

K. Youcef-Toumi; D. A. Gutz

1989-01-01

269

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.

Nanoscale Informal Science Education Network

2010-01-01

270

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

271

Illinois task force on global climate change  

SciTech Connect

The purpose of this report is to document progress in the areas of national policy development, emissions reduction, research and education, and adaptation, and to identify specific actions that will be undertaken to implement the Illinois state action plan. The task force has been tracking national and international climate change policy, and helping shape national policy agenda. Identification and implementation of cost-effective mitigation measures has been performed for emissions reduction. In the area of research and education, the task force is developing the capacity to measure climate change indicators, maintaining and enhancing Illinois relevant research, and strengthening climate change education. Activities relevant to adaptation to new policy include strengthening water laws and planning for adaptation. 6 figs., 4 tabs.

Griffin, B.S. [Illinois Dept. of Natural Resources, Springfield, IL (United States)

1996-12-31

272

Force generation in a regrowing eukaryotic flagellum  

NASA Astrophysics Data System (ADS)

Flagella are whip-like organelles with a complex internal structure, the axoneme, highly conserved across eukaryotic species. The highly regulated activity of motor proteins arranged along the axoneme moves the flagellum in the surrounding fluid, generating forces that can be used for swimming or fluid propulsion. Although our understanding of the general mechanism behind flagellar motion is well established, the details of its implementation in a real axoneme is still poorly understood. Here we explore the inner working of the eukaryotic flagellum using a uniflagellated mutant of the unicellular green alga Chlamydomonas reinhardtii to investigate in detail the force and power generated by a moving flagellum during axonemal regrowth after deflagellation. These experiments will contribute to our understanding of the inner working of the eukaryotic flagellum.

Polin, Marco; Bruneau, Bastien; Johnson, Thomas; Goldstein, Raymond

2012-02-01

273

The task force process  

SciTech Connect

This paper focuses on the unique aspects of the Fernald Citizens Task Force process that have contributed to a largely successful public participation effort at Fernald. The Fernald Citizens Task Force passed quickly by many procedural issues. Instead, the Task Force concentrated on (a) educating itself about the site, its problems, and possible solutions, and (b) choosing a directed way to approach its mandate: To make recommendations on several {open_quotes}big picture{close_quotes} issues, including future use of the site, cleanup levels, waste disposition, and cleanup priorities. This paper presents the approach used at Fernald for establishing and running a focused site-specific advisory board, the key issues that have been faced, and how these issues were resolved. The success of Fernald in establishing a strong and functioning site-specific advisory board serves as a useful model for other DOE facilities, although the Fernald model is just one of many approaches that can be taken. However, the approach presented here has worked extremely well for Fernald.

Applegate, J.S. [Univ. of Cincinnati, OH (United States)

1995-01-31

274

Modified Entropic Force  

E-print Network

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 gravitational field, so the modified entropic force formula is an extension of the Newtonian gravity to weak field. On the contrary, General Relativity extends Newtonian gravity to strong field case. Corresponding to Debye temperature, there exists a Debye acceleration g_D. It is found the Debye acceleration is g_D=10^{-15}N kg^{-1}. This acceleration is very much smaller than the gravitational acceleration 10^{-4}N kg^{-1} which is felt by the Neptune and the gravitational acceleration 10^{-10}N kg^{-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.

Changjun Gao

2010-04-19

275

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

276

International Water Association  

NSDL National Science Digital Library

A worldwide organization of water professionals, the International Water Association's (IWA) Web site illustrates its commitment "to help water professionals create innovative, pragmatic, and sustainable solutions to challenging global water needs." Visitors can discover IWA's many activities from conferences and forums to task forces. Researchers can discover the various IWS groups that specialize in topics including Source Management, Education, Health, Management Training, and Water Quality Management. Although many of the publications are restricted to members, educators and students can read reports from the Sustainability in Water Sector and abstracts from IWA journals.

277

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

278

Medium-Assisted Vacuum Force  

NASA Astrophysics Data System (ADS)

We discuss some implications of a very recently obtained result for the force on a slab in a planar cavity based on the calculation of the vacuum Lorentz force [C.Raabe and D.-G. Welsch, Phys. Rev. A 71 (2005) 013814]. We demonstrate that, according to this formula, the total force on the slab consists of a medium-screened Casimir force and, in addition to it, a medium-assisted force. The sign of of the medium-assisted force is determined solely by the properties of the cavity mirrors. In the Lifshitz configuration, this force is proportional to 1/d at small distances and is very small compared with the corresponding van der Waals force. At large distances, however, it is proportional to 1/d4 and comparable with the Casimir force, especially for denser media. The exponents in these power laws decrease by 1 in the case of a thin slab. The formula for the medium-assisted force also describes the force on a layer of the cavity medium, which has similar properties. For dilute media, it implies an atom-mirror interaction of the Coulomb type at small and of the Casimir-Polder type at large atom-mirror distances. For a perfectly reflecting mirror, the latter force is effectively only three-times smaller than the Casimir-Polder force.

Tomaš, M. S.

279

Quantifying immediate radiative forcing by black carbon and organic matter with the Specific Forcing Pulse  

NASA Astrophysics Data System (ADS)

Climatic effects of short-lived climate forcers (SLCFs) differ from those of long-lived greenhouse gases, because they occur rapidly after emission and because they depend upon the region of emission. The distinctive temporal and spatial nature of these impacts is not captured by measures that rely on global averages or long time integrations. Here, we propose a simple measure, the Specific Forcing Pulse (SFP), to quantify climate warming or cooling by these pollutants, where we define "immediate" as occurring primarily within the first year after emission. SFP is the amount of energy added to or removed from a receptor region in the Earth-atmosphere system by a chemical species, per mass of emission in a source region. We limit the application of SFP to species that remain in the atmosphere for less than one year. Metrics used in policy discussions, such as total forcing or global warming potential, are easily derived from SFP. However, SFP conveys purely physical information without incurring the policy implications of choosing a time horizon for the global warming potential. Using one model (Community Atmosphere Model, or CAM), we calculate values of SFP for black carbon (BC) and organic matter (OM) emitted from 23 source-region combinations. Global SFP for both atmosphere and cryosphere impacts is divided among receptor latitudes. SFP is usually greater for open-burning emissions than for energy-related (fossil-fuel and biofuel) emissions because of the timing of emission. Global SFP for BC varies by about 45% for energy-related emissions from different regions. This variation would be larger except for compensating effects. When emitted aerosol has larger cryosphere forcing, it often has lower atmosphere forcing because of less deep convection and a shorter atmospheric lifetime. A single model result is insufficient to capture uncertainty. We develop a best estimate and uncertainties for SFP by combining forcing results from 12 additional models. We outline a framework for combining a large number of simple models with a smaller number of enhanced models that have greater complexity. Adjustments for black carbon internal mixing and for regional variability are discussed. Emitting regions with more deep convection have greater model diversity. Our best estimate of global-mean SFP is +1.03 ± 0.52 GJ g-1 for direct atmosphere forcing of black carbon, +1.15 ± 0.53 GJ g-1 for black carbon including direct and cryosphere forcing, and -0.064 (-0.02, -0.13) GJ g-1 for organic matter. These values depend on the region and timing of emission. The lowest OM:BC mass ratio required to produce a neutral effect on top-of-atmosphere direct forcing is 15:1 for any region. Any lower ratio results in positive direct forcing. However, important processes, particularly cloud changes that tend toward cooling, have not been included here. Global-average SFP for energy-related emissions can be converted to a 100-year GWP of about 740 ± 370 for BC without snow forcing, and 830 ± 440 with snow forcing. 100-year GWP for OM is -46 (-18, -92). Best estimates of atmospheric radiative impact (without snow forcing) by black and organic matter are +0.47 ± 0.26 W m-2 and -0.17 (-0.07, -0.35) W m-2 for BC and OM, respectively, assuming total emission rates of 7.4 and 45 Tg yr-1. Anthropogenic forcing is +0.40 ± 0.18 W m-2 and -0.13 (-0.05, -0.25) W m-2 for BC and OM, respectively, assuming anthropogenic emission rates of 6.3 and 32.6 Tg yr-1. Black carbon forcing is only 18% higher than that given by the Intergovernmental Panel on Climate Change (IPCC), although the value presented here includes enhanced absorption due to internal mixing.

Bond, T. C.; Zarzycki, C.; Flanner, M. G.; Koch, D. M.

2011-02-01

280

Bridge Types: Tensile & Compressive Forces  

NSDL National Science Digital Library

Students explore how tension and compression forces act on three different bridge types. Using sponges, cardboard and string, they create models of beam, arch and suspension bridges and apply forces to understand how they disperse or transfer these loads.

Integrated Teaching and Learning Program,

281

Vibrational spectrum and force field of dimethyldimethoxysilane  

SciTech Connect

Experimental data is presented on the spectra of (CH/sub 3/)/sub 2/Si(OCH/sub 3/)/sub 2/ (I), (CH/sub 3/)/sub 2/Si(OCD/sub 3/)/sub 2/ (II), and (CD/sub 3/)/sub 2/Si(OCH/sub 3/)/sub 2/ (III). The results of the determination of the force constants on the basis of the optimization of the solution of the inverse mechanical problem of the theory of molecular vibrations with consideration of all the internal degrees of freedom with the exception of the coordinates corresponding to internal rotations are discussed. Raman spectra of I, II, and III in the liquid phase is shown and the IR spectra of amorphous films of I, II, and III are illustrated.

Tenisheva, T.F.; Lazarev, A.N.

1986-01-01

282

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...

283

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

284

Forced convective heat transfer in channels with internal longitudinal fins  

E-print Network

dimensionless coordinate, z/D, Figure 3. 2 fin-to-wall average heat flux ratio fin tip-to-wall average heat flux ratio density wall shear stress dimensionless temperature, Equation (3. l4) d imensionless bulk temperature dimensionless surface temperature.... In the analysis, the following dimensionless parameters are employed: X = x/D, S = s/D, F = tf/D, Y = y/D, L = I/D, and W = tw/D. (3 1) adiabatic Figure 3. 1 Flow Cross Section of Finned Channel with Dimensions R = -~S-F 2 L R = L F/2 S/2 Figure 3...

Ong, Liang Eng

1987-01-01

285

Permeability of continental crust influenced by internal and external forcing  

E-print Network

fluid flux and permeability in the deep, ductile crust, where fluid pressures are typically near, intact shales, and fault gouge, to values as high as 10)7 m2 in well-sorted gravels. In the upper crust

286

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

287

International Orientation  

E-print Network

students and fellow international students. Refreshments will be available. UCD Global Lounge, Gerard Manley Hopkins International Centre Tuesday 3rd September 2013 Time Event Where 8.00-17.00 Airport your ticket in the Global Lounge. Sports Centre Bus Stop 13.00 Getting involved in UCD Life Information

288

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

289

International reputation  

E-print Network

g African Studies g East Asian and Pacific Studies* g European Union Studies* g Global Studies* g 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.

290

Force field of monoethanolamine  

SciTech Connect

Ab initio calculations and canonical molecular dynamics simulations were performed to obtain a force field of monoethanolamine (MEA). The molecule is modeled by seven charged sites, and the force field includes intramolecular degrees of freedom and intermolecular interactions. The charges obtained in the energy minimization procedure reproduce the experimental geometry, dipole moment, and the most stable conformation. Molecular dynamics simulations were carried out in the liquid phase and in the liquid-vapor equilibrium state. Simulations in the liquid region give information about hydrogen bond formation, while simulations in the two-phase region allow the determination of coexisting densities and surface tension as functions of temperature. The hydrogen bond is favored when the hydrogen of the hydroxyl group is close to a nitrogen or to an oxygen of another molecule, and the strength in both cases is the same. Radial distribution functions involving hydrogens and oxygen in the hydroxyl group of MEA are compared with those of water at 298 K, and a similar structure is found for the first neighbor of atoms. The proposed force field gives a good description of the liquid-vapor coexistence of MEA. The liquid density obtained in simulations of the liquid-vapor equilibrium at 298 K is 1.003 g/cm{sup 3} versus the experimental value of 1.012 g/cm{sup 3}. The estimated critical point is located at 583.9 K and 0.32 g/cm{sup 3} in comparison with the experimental result of 614 K and 0.3116 g/cm{sup 3}, respectively. At 323 K the calculated surface tension if 43.2 {+-} 2.5 nM/m while the experimental value is 44.81 mN/m.

Alejandre, J.; Rivera, J.L.; Mora, M.A.; Garza, V. de la

2000-02-17

291

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

292

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

293

The Impact of Institutional Forces on Software Metrics Programs  

Microsoft Academic Search

Software metrics programs are an important part of a software organization's productivity and quality initiatives as precursors to process-based improvement programs. Like other innovative practices, the implementation of metrics programs is prone to influences from the greater institutional environment the organization exists in. In this paper, we study the influence of both external and internal institutional forces on the assimilation

Anandasivam Gopal; Tridas Mukhopadhyay; Mayuram S. Krishnan

2005-01-01

294

Developing A Spiral Scanning Method Using Atomic Force Microscopy  

E-print Network

of the PZT scanner for the lateral positioning of the AFM scanner stage. In this control design, an internal the effectiveness of the proposed scheme. I. INTRODUCTION Rapid progress of nano-technology is due to the ability to measure, manipulate, and control of matters in nano-scale. Atomic force microscope (AFM) is one of them

Pota, Himanshu Roy

295

Force Control of Robot Manipulators  

Microsoft Academic Search

The state of the art of force control for robot manipulators is surveyed in this article. An overview and a unified description of the two major approaches to force control are presented. Several research topics related to force control are also surveyed

Tsuneo Yoshikawa

2000-01-01

296

Air Force ROTC Detachment 165  

E-print Network

Air Force ROTC Detachment 165 2011 OPEN HOUSE We will be opening our doors on the evening of April would like more information on the Air Force ROTC program at Georgia Tech and our crosstown recruiting@afrotc.gatech.edu 404-894-7386 Air Force ROTC Detachment 165 The Georgia Institute of Technology

Li, Mo

297

Acid dissolution hydrodynamic force analysis  

Microsoft Academic Search

The purpose of this calculation is to analyze the hydrodynamic forces associated with the in-tank piping feeding the tank fluid agitation eductor (sparger), as well as eductor induced forces. These forces will be used as input to the structural analysis of the support structure used for the acid dissolution assembly, and the acid dissolution assembly itself.

2003-01-01

298

Acid dissolution hydrodynamic force analysis  

SciTech Connect

The purpose of this calculation is to analyze the hydrodynamic forces associated with the in-tank piping feeding the tank fluid agitation eductor (sparger), as well as eductor induced forces. These forces will be used as input to the structural analysis of the support structure used for the acid dissolution assembly, and the acid dissolution assembly itself.

WHITE, M.A.

2003-05-21

299

Magnetic microposts as an approach to apply forces to living cells  

PubMed Central

Cells respond to mechanical forces whether applied externally or generated internally via the cytoskeleton. To study the cellular response to forces separately, we applied external forces to cells via microfabricated magnetic posts containing cobalt nanowires interspersed among an array of elastomeric posts, which acted as independent sensors to cellular traction forces. A magnetic field induced torque in the nanowires, which deflected the magnetic posts and imparted force to individual adhesions of cells attached to the array. Using this system, we examined the cellular reaction to applied forces and found that applying a step force led to an increase in local focal adhesion size at the site of application but not at nearby nonmagnetic posts. Focal adhesion recruitment was enhanced further when cells were subjected to multiple force actuations within the same time interval. Recording the traction forces in response to such force stimulation revealed two responses: a sudden loss in contractility that occurred within the first minute of stimulation or a gradual decay in contractility over several minutes. For both types of responses, the subcellular distribution of loss in traction forces was not confined to locations near the actuated micropost, nor uniformly across the whole cell, but instead occurred at discrete locations along the cell periphery. Together, these data reveal an important dynamic biological relationship between external and internal forces and demonstrate the utility of this microfabricated system to explore this interaction. PMID:17804810

Sniadecki, Nathan J.; Anguelouch, Alexandre; Yang, Michael T.; Lamb, Corinne M.; Liu, Zhijun; Kirschner, Stuart B.; Liu, Yaohua; Reich, Daniel H.; Chen, Christopher S.

2007-01-01

300

Causal Entropic Forces  

NASA Astrophysics Data System (ADS)

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.

Wissner-Gross, A. D.; Freer, C. E.

2013-04-01

301

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

302

Automated connector force testing  

NASA Astrophysics Data System (ADS)

A gaging system was developed to modernize the force testing of electrical connectors and components using an IBM personal computer based data acquisition system. Two mechanical fixtures were fabricated using load cells and LVDT transducers to perform the measurements. General purpose software routines perform the operator interface, data acquisition, storage, retrieval, and printout. The system will perform statistical analysis of the part data to aid in evaluation of the manufacturing process. The modular software concept allows the system to be tailored for many other applications using a text editor.

Timmons, L. A.

1992-11-01

303

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.

304

Forced to Fracture  

NSDL National Science Digital Library

Students learn how forces affect the human skeletal system through fractures and why certain bones are more likely to break than others depending on their design and use in the body. They learn how engineers and doctors collaborate to design effective treatments with consideration for the location, fracture severity and patient age, as well as the use of biocompatible materials. Learning the lesson content prepares students for the associated activity in which they test small animal bones to failure and then design treatment repair plans.

National Science Foundation GK-12 and Research Experience for Teachers (RET) Programs,

305

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

306

Nonequilibrium forces between neutral atoms mediated by a quantum field  

SciTech Connect

We study forces between two neutral atoms, modeled as three-dimensional harmonic oscillators, arising from mutual influences mediated by an electromagnetic field but not from their direct interactions. We allow as dynamical variables the center-of-mass motion of the atom, its internal degrees of freedom, and the quantum field treated relativistically. We adopt the method of nonequilibrium quantum field theory which can provide a first-principles, systematic, and unified description including the intrinsic and induced dipole fluctuations. The inclusion of self-consistent back-actions makes possible a fully dynamical description of these forces valid for general atom motion. In thermal equilibrium we recover the known forces--London, van der Waals, and Casimir-Polder--between neutral atoms in the long-time limit. We also reproduce a recently reported force between atoms when the system is out of thermal equilibrium at late times. More noteworthy is the discovery of the existence of a type of (or identification of the source of some known) interatomic force which we call the ''entanglement force,'' originating from the quantum correlations of the internal degrees of freedom of entangled atoms.

Behunin, Ryan O. [Maryland Center for Fundamental Physics, Department of Physics, University of Maryland, College Park, Maryland 20742 (United States); Hu, Bei-Lok [Maryland Center for Fundamental Physics, Department of Physics, University of Maryland, College Park, Maryland 20742 (United States); Joint Quantum Institute, University of Maryland, College Park, Maryland 20742 (United States)

2010-08-15

307

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

308

van der Waals Forces  

PubMed Central

A practical method for examining and calculating van der Waals forces is derived from Lifshitz' theory. Rather than treat the total van der Waals energy as a sum of pairwise interactions between atoms, the Lifshitz theory treats component materials as continua in which there are electromagnetic fluctuations at all frequencies over the entire body. It is necessary in principle to use total macroscopic dielectric data from component substances to analyze the permitted fluctuations; in practice it is possible to use only partial information to perform satisfactory calculations. The biologically interesting case of lipid-water systems is considered in detail for illustration. The method gives good agreement with measured van der Waals energy of interaction across a lipid film. It appears that fluctuations at infrared frequencies and microwave frequencies are very important although these are usually ignored in preference to UV contributions. “Retardation effects” are such as to damp out high frequency fluctuation contributions; if interaction specificity is due to UV spectra, this will be revealed only at interactions across <200 angstrom (A). Dependence of van der Waals forces on material electric properties is discussed in terms of illustrative numerical calculations. PMID:5449915

Ninham, B. W.; Parsegian, V. A.

1970-01-01

309

Forced emigration, favourable outcomes.  

PubMed

The discipline of public health and preventive medicine in Australia and New Zealand had its genesis in the advocacy of 18th and 19th century military pioneers. Military (Royal Navy and British Army) surgeons were posted to Australia as part of their non-discretionary duty. Civilian doctors emigrated variously for adventure, escapism and gold fever. One group, a particularly influential group disproportionate to their numbers, came in one sense as forced emigrants because of chronic respiratory disease in general, and tuberculosis in particular. Tuberculosis was an occupational hazard of 19th century medical and surgical practice throughout western Europe. This paper analyses six examples of such emigration which had, perhaps unforeseen at the time, significant results in the advancement of public health. Such emigration was in one sense voluntary, but in another was forced upon the victims in their quest for personal survival. In Australia, such medical individuals became leading advocates and successful catalysts for change in such diverse fields as social welfare, public health, the preventive aspects of medical practice, child health, nutrition and medical education. A number of such public health pioneers today have no physical memorials; but their influence is to be seen in the ethos of medical practice in Australia and New Zealand today. Their memory is further perpetuated in the names of Australian native wildflowers and trees that symbolise not only a healthy environment but the long-term investment, accrued with interest, of the institution of public health measures for which their advocacy achieved much success. PMID:11688628

Pearn, J

2001-10-01

310

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,

311

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

312

Theory of rapid force spectroscopy  

PubMed Central

In dynamic force spectroscopy, single (bio-)molecular bonds are actively broken to assess their range and strength. At low loading rates, the experimentally measured statistical distributions of rupture forces can be analysed using Kramers’ theory of spontaneous unbinding. The essentially deterministic unbinding events induced by the extreme forces employed to speed up full-scale molecular simulations have been interpreted in mechanical terms, instead. Here we start from a rigorous probabilistic model of bond dynamics to develop a unified systematic theory that provides exact closed-form expressions for the rupture force distributions and mean unbinding forces, for slow and fast loading protocols. Comparing them with Brownian dynamics simulations, we find them to work well also at intermediate pulling forces. This renders them an ideal companion to Bayesian methods of data analysis, yielding an accurate tool for analysing and comparing force spectroscopy data from a wide range of experiments and simulations. PMID:25079911

Bullerjahn, Jakob T.; Sturm, Sebastian; Kroy, Klaus

2014-01-01

313

Pressure, Force, Muscles and Massage  

NSDL National Science Digital Library

The human body is constantly being subjected to external forces. The relation between force and pressure is straightforward. The more force exerted, the greater the pressure, but the effect of area on pressure is somewhat more subtle. Through the process of massage students apply their understanding of forces and pressures to enhance the relaxation of their lab partner's forearm. A proper understanding of the concept of pressure is essential to an understanding of most areas of physiology. This activity provides students with a feeling for what pressure is and how it is related to force and area. Students determine the pressure exerted on the bottoms of their feet under a variety of circumstances. In each case, the force exerted is body weight. But the area over which that force is exerted differs, depending on whether one is standing on two feet, one foot or tiptoe (one-foot.)

BEGIN:VCARD VERSION:2.1 FN:Kristin Shields N:Shields; Kristin ORG:Vanden High School REV:2005-04-12 END:VCARD

1995-06-30

314

Flow mechanotransduction regulates traction forces, intercellular forces, and adherens junctions  

PubMed Central

Endothelial cells respond to fluid shear stress through mechanotransduction responses that affect their cytoskeleton and cell-cell contacts. Here, endothelial cells were grown as monolayers on arrays of microposts and exposed to laminar or disturbed flow to examine the relationship among traction forces, intercellular forces, and cell-cell junctions. Cells under laminar flow had traction forces that were higher than those under static conditions, whereas cells under disturbed flow had lower traction forces. The response in adhesion junction assembly matched closely with changes in traction forces since adherens junctions were larger in size for laminar flow and smaller for disturbed flow. Treating the cells with calyculin-A to increase myosin phosphorylation and traction forces caused an increase in adherens junction size, whereas Y-27362 cause a decrease in their size. Since tugging forces across cell-cell junctions can promote junctional assembly, we developed a novel approach to measure intercellular forces and found that these forces were higher for laminar flow than for static or disturbed flow. The size of adherens junctions and tight junctions matched closely with intercellular forces for these flow conditions. These results indicate that laminar flow can increase cytoskeletal tension while disturbed flow decreases cytoskeletal tension. Consequently, we found that changes in cytoskeletal tension in response to shear flow conditions can affect intercellular tension, which in turn regulates the assembly of cell-cell junctions. PMID:22447948

Ting, Lucas H.; Jahn, Jessica R.; Jung, Joon I.; Shuman, Benjamin R.; Feghhi, Shirin; Han, Sangyoon J.; Rodriguez, Marita L.

2012-01-01

315

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.

316

Force Limit System  

NASA Technical Reports Server (NTRS)

The Force Limit System (FLS) was developed to protect test specimens from inadvertent overload. The load limit value is fully adjustable by the operator and works independently of the test system control as a mechanical (non-electrical) device. When a test specimen is loaded via an electromechanical or hydraulic test system, a chance of an overload condition exists. An overload applied to a specimen could result in irreparable damage to the specimen and/or fixturing. The FLS restricts the maximum load that an actuator can apply to a test specimen. When testing limited-run test articles or using very expensive fixtures, the use of such a device is highly recommended. Test setups typically use electronic peak protection, which can be the source of overload due to malfunctioning components or the inability to react quickly enough to load spikes. The FLS works independently of the electronic overload protection.

Pawlik, Ralph; Krause, David; Bremenour, Frank

2011-01-01

317

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

318

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

319

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

320

From mechanical force to RhoA activation  

PubMed Central

Throughout their lives all cells constantly experience and respond to various mechanical forces. These frequently originate externally but can also arise internally as a result of the contractile actin cytoskeleton. Mechanical forces trigger multiple signaling pathways. Several converge and result in the activation of the GTPase RhoA. In this review we focus on the pathways by which mechanical force leads to RhoA regulation, especially when force is transmitted via cell adhesion molecules that mediate either cell-matrix or cell-cell interactions. We discuss both the upstream signaling events that lead to activation of RhoA, as well as the downstream consequences of this pathway. These include not only cytoskeletal reorganization and, in a positive feedback loop, increased myosin-generated contraction, but also profound effects on gene expression and differentiation. PMID:22931484

Lessey, Elizabeth C.; Guilluy, Christophe; Burridge, Keith

2012-01-01

321

Mass effects and internal space geometry in triatomic reaction dynamics  

NASA Astrophysics Data System (ADS)

The effect of the distribution of mass in triatomic reaction dynamics is analyzed using the geometry of the associated internal space. Atomic masses are appropriately incorporated into internal coordinates as well as the associated non-Euclidean internal space metric tensor after a separation of the rotational degrees of freedom. Because of the non-Euclidean nature of the metric in the internal space, terms such as connection coefficients arise in the internal equations of motion, which act as velocity-dependent forces in a coordinate chart. By statistically averaging these terms, an effective force field is deduced, which accounts for the statistical tendency of geodesics in the internal space. This force field is shown to play a crucial role in determining mass-related branching ratios of isomerization and dissociation dynamics of a triatomic molecule. The methodology presented can be useful for qualitatively predicting branching ratios in general triatomic reactions, and may be applied to the study of isotope effects.

Yanao, Tomohiro; Koon, Wang S.; Marsden, Jerrold E.

2006-05-01

322

Mass effects and internal space geometry in triatomic reaction dynamics  

SciTech Connect

The effect of the distribution of mass in triatomic reaction dynamics is analyzed using the geometry of the associated internal space. Atomic masses are appropriately incorporated into internal coordinates as well as the associated non-Euclidean internal space metric tensor after a separation of the rotational degrees of freedom. Because of the non-Euclidean nature of the metric in the internal space, terms such as connection coefficients arise in the internal equations of motion, which act as velocity-dependent forces in a coordinate chart. By statistically averaging these terms, an effective force field is deduced, which accounts for the statistical tendency of geodesics in the internal space. This force field is shown to play a crucial role in determining mass-related branching ratios of isomerization and dissociation dynamics of a triatomic molecule. The methodology presented can be useful for qualitatively predicting branching ratios in general triatomic reactions, and may be applied to the study of isotope effects.

Yanao, Tomohiro; Koon, Wang S.; Marsden, Jerrold E. [Control and Dynamical Systems, MC 107-81, California Institute of Technology, Pasadena, California 91125 (United States)

2006-05-15

323

Drag force models for the Stella satellite  

NASA Astrophysics Data System (ADS)

In the kinetic paradigm, the choice of the models of gaz-surface interaction plays a crucial role in the modeling of the drag effects. In this study, we recall the most used model for drag force (from Schamberg - 1959) and we compare it with another classical model (from Afonso - 1985), for the computation of orbital arcs of the Stella satellite over several years. The results obtained are better with the Afonso's model, regarding both computation residuals and estimated empirical coefficients of the drag force. Weekly orbital arcs are computed from SLR data tracked by the ILRS (International Laser Ranging Service) network with the GRGS (French Space Geodesy Research Group) GINS software and several configurations are tested (without estimation of any empiral coefficient for the drag force, estimation of one coefficient per arc, and estimation of coefficients with a six-hour sampling over the arc). Moreover, the study underlines the importance of estimating some parameters that describe the microstructure of the surface of the satellite.

Bernard, Etienne; Coulot, David; Deleflie, Florent; Pollet, Arnaud

324

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

325

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.

326

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.

327

International Undergraduate  

E-print Network

Union Studies · Exceptionality in man Learning · Finance · Finance & Economics · Financial Economics · International ations · Islamic Studies · Italian · Italian Culture & Communication Studies · Italian Second

Toronto, University of

328

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...

329

Coordinated dynamic hybrid position\\/force control for multiple robot manipulators handling one constrained object  

Microsoft Academic Search

A cooperative dynamic hybrid control method for multimotion robotic mechanisms handling a single object whose motion is constrained by environment is discussed. This method takes the manipulator dynamics and object dynamics into consideration and is for controlling the motion of the object as well as for controlling the constraint force and the internal force. The following results are obtained: (1)

Tsuneo Yoshikawa; Xinzhi Zheng

1990-01-01

330

Project Title: New Zealand Defence Force & Engineers: Representations of Military Technology  

E-print Network

technologies (weapons, sonar, aircraft, etc) perceived? What are engineering students looking for in a job? What stops engineering students from considering the navy or air force specifically as an employer of choice? What would make a difference to choosing Defence Force #12;as a job/career? The intern will focus

Hickman, Mark

331

The influence of seepage forces on ground reaction curve of circular opening  

Microsoft Academic Search

When a tunnel is excavated underneath a groundwater table, groundwater flows into the tunnel and consequently, seepage forces act on the cross-section of the tunnel. Such seepage forces significantly affect the ground reaction curve, which is defined by the relationship between the internal pressure and displacement of the tunnel wall. From a practical point of view, a simplified analytical solution

Seok-Won Lee; Jong-Won Jung; Seok-Woo Nam; In-Mo Lee

2007-01-01

332

The effect of muscle stiffness and damping on simulated impact force peaks during running  

Microsoft Academic Search

It has been frequently reported that vertical impact force peaks during running change only minimally when changing the midsole hardness of running shoes. However, the underlying mechanism for these experimental observations is not well understood. An athlete has various possibilities to influence external and internal forces during ground contact (e.g. landing velocity, geometrical alignment, muscle tuning, etc.). The purpose of

Benno M Nigg; Wen Liu

1999-01-01

333

Corrected direct force balance method for atomic force microscopy lateral force calibration  

SciTech Connect

This paper reports corrections and improvements of the previously reported direct force balance method (DFBM) developed for lateral calibration of atomic force microscopy. The DFBM method employs the lateral force signal obtained during a force-distance measurement on a sloped surface and relates this signal to the applied load and the slope of the surface to determine the lateral calibration factor. In the original publication [Rev. Sci. Instrum. 77, 043903 (2006)], the tip-substrate contact was assumed to be pinned at the point of contact, i.e., no slip along the slope. In control experiments, the tip was found to slide along the slope during force-distance curve measurement. This paper presents the correct force balance for lateral force calibration.

Asay, David B.; Hsiao, Erik; Kim, Seong H. [Department of Chemical Engineering, The Pennsylvania State University, University Park, Pennsylvania 16802 (United States)

2009-06-15

334

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

335

Expanding the role of internal facility assessments  

SciTech Connect

The US Air Force (USAF) Environmental Compliance Assessment and Management Program (ECAMP) is an effective and comprehensive system to evaluate environmental compliance at individual USAF installations. The ECAMP assessment is typically performed by a team of experts from the installation`s Major Command (MAJCOM) Headquarters, and is often augmented with technical contractor support. As directed by Air Force policy, an external ECAMP assessment is required at a minimum of every three years for each installation. In the intervening years, each installation is required to perform an internal ECAMP assessment, with its own personnel and resources. Even though team composition differs, the internal and external ECAMP assessments are likely to be very similar in scope, objectives, and deliverables. For over nine years, Argonne National Laboratory (ANL) has supported several Air Force MAJCOMs in performing their external ECAMP assessments. More recently, ANL has also had the opportunity to provide technical support and training at individual installations during their preparation and conduct of internal ECAMP assessments. From that experience, the authors have learned that the quality and value of the internal assessment is enhanced by making it a vehicle for training, planning, and interaction among organizations. Various strategies and techniques have been successfully employed to derive maximum benefit and insight from the internal assessment process. Experiences that involve expanding the scope and objectives of internal assessments to meet specific goals are presented. The expansion of scope and objectives include preassessment training, planning, and evaluator interactions as part of the overall internal assessment process.

Kolpa, R.L.; Levenson, J.B. [Argonne National Lab., IL (United States); Weaver, M.A. [Headquarters Air Force Materiel Command, Wright-Patterson AFB, OH (United States)

1996-05-01

336

Black carbon radiative forcing over the Tibetan Plateau  

NASA Astrophysics Data System (ADS)

We 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

337

Traction Forces of Neutrophils Migrating on Compliant Substrates  

PubMed Central

Proper functioning of the innate immune response depends on migration of circulating neutrophils into tissues at sites of infection and inflammation. Migration of highly motile, amoeboid cells such as neutrophils has significant physiological relevance, yet the traction forces that drive neutrophil motion in response to chemical cues are not well characterized. To better understand the relationship between chemotactic signals and the organization of forces in motile neutrophils, force measurements were made on hydrogel surfaces under well-defined chemotactic gradients created with a microfluidic device. Two parameters, the mean chemoattractant concentration (CM) and the gradient magnitude (?c/?x) were varied. Cells experiencing a large gradient with CM near the chemotactic receptor KD displayed strong punctate centers of uropodial contractile force and strong directional motion on stiff (12 kPa) surfaces. Under conditions of ideal chemotaxis—cells in strong gradients with mean chemoattractant near the receptor KD and on stiffer substrates—there is a correlation between the magnitude of force generation and directional motion as measured by the chemotactic index. However, on soft materials or under weaker chemotactic conditions, directional motion is uncorrelated with the magnitude of traction force. Inhibition of either ?2 integrins or Rho-associated kinase, a kinase downstream from RhoA, greatly reduced rearward traction forces and directional motion, although some vestigial lamellipodium-driven motility remained. In summary, neutrophils display a diverse repertoire of methods for organizing their internal machinery to generate directional motion. PMID:21806925

Jannat, Risat A.; Dembo, Micah; Hammer, Daniel A.

2011-01-01

338

Experimental characterization of jet static forces impacting waste tank components  

SciTech Connect

Westinghouse Hanford Company plans to install mixer pumps in doubleshell waste tanks to mobilize and suspend settled sludge to allow eventual retrieval for treatment and permanent storage. The mixer pumps produce high momentum, horizontally directed jets that impact and mobilize the sludge and mix it into slurry for removal. There is concern that the force of the jet may damage tank internal components in its path. Scaled experiments were conducted to characterize the velocity profiles of the floor jet and to quantify the drag coefficients and impact forces for three tank components: radiation dry well, air lift circulator, and steam coil. Jet impact forces were measured on the scaled models at a 4 to 1 range of hydraulically scaled flow rates and a scaled range of distances between discharge nozzle and test component. The test were designed to provide hydraulic similarity between test conditions and expected actual waste tank conditions by using equal Reynolds number the jet maximum velocity impacted the test component. Forces measured on the models were used to calculate expected forces on the full scale components. Correlations of force on the test article versus distance from the nozzle were derived for the radiation dry well and air lift circulator based on the velocity correlation and drag parameter. The force data were also used to derive equivalent drag parameters which accounted for component shape factors including variation of jet impact area on the test article with distance from the nozzle. 8 refs., 44 figs., 42 tabs.

Bamberger, J.A.; Bates, J.M. (Pacific Northwest Lab., Richland, WA (USA)); Waters, E.D. (Westinghouse Hanford Co., Richland, WA (USA))

1990-06-01

339

Entropic forces in Brownian motion  

NASA Astrophysics Data System (ADS)

Interest in the concept of entropic forces has risen considerably since Verlinde proposed in 2011 to interpret the force in Newton's second law and gravity as entropic forces. 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 article, it is shown that at least two types of entropic force can be identified in three-dimensional Brownian motion. This analysis yields simple derivations of known results of Brownian motion, Hooke's law, and—applying an external (non-radial) force—Curie's law and the Langevin-Debye equation.

Roos, Nico

2014-12-01

340

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

341

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

342

22 CFR 130.3 - Armed forces.  

Code of Federal Regulations, 2011 CFR

... 2011-04-01 2011-04-01 false Armed forces. 130.3 Section 130.3 Foreign Relations...CONTRIBUTIONS, FEES AND COMMISSIONS § 130.3 Armed forces. Armed forces means the army, navy, marine, air force,...

2011-04-01

343

22 CFR 130.3 - Armed forces.  

Code of Federal Regulations, 2010 CFR

... 2010-04-01 2010-04-01 false Armed forces. 130.3 Section 130.3 Foreign Relations...CONTRIBUTIONS, FEES AND COMMISSIONS § 130.3 Armed forces. Armed forces means the army, navy, marine, air force,...

2010-04-01

344

Inverse Calculation of Aerosol Forcing  

Microsoft Academic Search

Change in global mean surface temperature (GMST) is driven by total forcing, the major components of which are thought to be increased concentrations of greenhouse gases and aerosols. While greenhouse gas forcing is relatively well known, aerosol forcing remains quite uncertain, with central value (1750-2005) of -1.2 W m-2 [range -0.6 to -2.4 W m-2, 5-95%; IPCC AR4, 2007; negative

S. E. Schwartz

2007-01-01

345

The Science of Spring Force  

NSDL National Science Digital Library

Students use data acquisition equipment to learn about force and displacement in regard to simple and complex machines. In the engineering world, materials and systems are tested by applying forces and measuring the resulting displacements. The relationship between the force applied on a material, and its resulting displacement, is a distinct property of the material, which is measured in order to evaluate the material for correct use in structures and machines.

AMPS GK-12 Program,

346

Interpretation and use of FRAX in clinical practice - position paper of the International Osteoporosis Foundation and the International Society for Clinical Densitometry  

Technology Transfer Automated Retrieval System (TEKTRAN)

The International Osteoporosis Foundation (IOF) and the International Society for Clinical Densitometry (ISCD) appointed a joint Task Force to develop resource documents in order to make recommendations on how to improve FRAX and better inform clinicians who use FRAX. The Task Force met in November...

347

Hydrodynamic force microscopy  

NASA Astrophysics Data System (ADS)

Microfluidic networks and microporous materials have long been of interest in areas such as hydrology, petroleum engineering, chemical and electrochemical engineering, medicine and biochemical engineering. With the emergence of new processes in gas separation, cell sorting, ultrafiltration, and advanced materials synthesis, the importance of building a better qualitative and quantitative understanding of these key technologies has become apparent. However, microfluidic measurement and theory is still relatively underdeveloped, presenting a significant obstacle to the systematic design of microfluidic devices and materials. Theoretical challenges arise from the breakdown of classical viscous flow models as the flow dimensions approach the mean free path of individual molecules. Experimental challenges arise from the lack of flow profilometry techniques at sub-micron length scales. Here we present an extension of scanning probe microscopy techniques, which we have termed Hydrodynamic Force Microscopy (HFM). HFM exploits fluid drag to profile microflows and to map the permeability of microporous materials. In this technique, an atomic force microscope (AFM) cantilever is scanned close to a microporous sample surface. The hydrodynamic interactions arising from a pressure-driven flow through the sample are then detected by mapping the deflection of an AFM cantilever. For gas flows at atmospheric pressure, HFM has been shown to achieve a velocity sensitivity of 1 cm/s with a spatial resolution of ˜ 10 nm. This compares very favorably to established techniques such as hot-wire and laser Doppler anemometry, whose spatial resolutions typically exceed 1 mum and which may rely on the use of tracer particles or flow markers1. We demonstrate that HFM can successfully profile Poiseuille flows inside pores as small as 100 nm and can distinguish Poiseuille flow from uniform flow for short entry lengths. HFM detection of fluid jets escaping from porous samples can also reveal a "permeability map" of a sample's pore structure, allowing us to distinguish between clear and blocked pores, even in cases where the subsurface fouling is undetectable by conventional AFM. The experimental data is discussed in context with theoretical aspects of HFM microflow measurement and practical limits of this technique. Finally, we conclude with variations of standard HFM techniques that show some promise for investigation of smaller nanometer-scale flows of gases and liquids.

Ulrich, Elaine Schmid

348

Coriolis Force on Your Arms  

NASA Astrophysics Data System (ADS)

The Coriolis force is a sideward force that acts on a rotating object as it moves toward or away from the center of rotation. It is important to long-range artillery and the formation of tornados, but we seldom experience this force on a human scale, unless we play on a merry-go-round or similar apparatus. This note describes a simple activity that lets us see the effect of the Coriolis force on our outstretched arms as they fall down to our sides while we rotate.

Johns, Robert

2003-12-01

349

Sensing mode atomic force microscope  

DOEpatents

An atomic force microscope is described having a cantilever comprising a base and a probe tip on an end opposite the base; a cantilever drive device connected to the base; a magnetic material coupled to the probe tip, such that when an incrementally increasing magnetic field is applied to the magnetic material an incrementally increasing force will be applied to the probe tip; a moveable specimen base; and a controller constructed to obtain a profile height of a specimen at a point based upon a contact between the probe tip and a specimen, and measure an adhesion force between the probe tip and the specimen by, under control of a program, incrementally increasing an amount of a magnetic field until a release force, sufficient to break the contact, is applied. An imaging method for atomic force microscopy involving measuring a specimen profile height and adhesion force at multiple points within an area and concurrently displaying the profile and adhesion force for each of the points is also described. A microscope controller is also described and is constructed to, for a group of points, calculate a specimen height at a point based upon a cantilever deflection, a cantilever base position and a specimen piezo position; calculate an adhesion force between a probe tip and a specimen at the point by causing an incrementally increasing force to be applied to the probe tip until the probe tip separates from a specimen; and move the probe tip to a new point in the group.

Hough, Paul V.; Wang, Chengpu

2004-11-16

350

Sensing mode atomic force microscope  

DOEpatents

An atomic force microscope is described having a cantilever comprising a base and a probe tip on an end opposite the base; a cantilever drive device connected to the base; a magnetic material coupled to the probe tip, such that when an incrementally increasing magnetic field is applied to the magnetic material an incrementally increasing force will be applied to the probe tip; a moveable specimen base; and a controller constructed to obtain a profile height of a specimen at a point based upon a contact between the probe tip and a specimen, and measure an adhesion force between the probe tip and the specimen by, under control of a program, incrementally increasing an amount of a magnetic field until a release force, sufficient to break the contact, is applied. An imaging method for atomic force microscopy involving measuring a specimen profile height and adhesion force at multiple points within an area and concurrently displaying the profile and adhesion force for each of the points is also described. A microscope controller is also described and is constructed to, for a group of points, calculate a specimen height at a point based upon a cantilever deflection, a cantilever base position and a specimen piezo position; calculate an adhesion force between a probe tip and a specimen at the point by causing an incrementally increasing force to be applied to the probe tip until the probe tip separates from a specimen; and move the probe tip to a new point in the group.

Hough, Paul V. C.; Wang, Chengpu

2006-08-22

351

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

352

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

353

Teaching International Law: Concepts in International Relations  

ERIC Educational Resources Information Center

This book is designed to introduce students to public international law. Topics covered include international public organizations, such as the United Nations and World Trade Organization, international courts, international human rights law, international trade law, and international environmental law. The goal of each study is to examine how…

Starbird, Caroline; Pettit, Jenny; Singleton, Laurel

2004-01-01

354

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

355

Surface forces studied with colloidal probe atomic force microscopy  

Microsoft Academic Search

Forces between surfaces are a determining factor for the performance of natural as well as synthetic colloidal systems, and play a crucial role in industrial production processes. Measuring these forces is a scientific and experimental challenge and over the years several techniques have been developed to measure the interaction between surfaces directly as a function of their separation distance. Colloidal

M. Giesbers

2001-01-01

356

77 FR 56845 - Meeting of the Community Preventive Services Task Force (Task Force)  

Federal Register 2010, 2011, 2012, 2013, 2014

...Prevention Meeting of the Community Preventive Services Task Force (Task Force) AGENCY: Centers for Disease Control and Prevention...next meeting of the Community Preventive Services Task Force (Task Force). The Task Force is independent and...

2012-09-14

357

International Cooperation in Big Science: High Energy Physics. Science Policy Study--Hearings Volume 4. Hearing before the Task Force on Science Policy of the Committee on Science and Technology, House of Representatives, Ninety-Ninth Congress, First Session (April 25, 1985).  

ERIC Educational Resources Information Center

Presented is the first in a series of four hearings on international cooperation in science. The focus of the hearing is international cooperation in big science, as personified by the field of high energy physics. The particular area of interest is the questions: What are the past experience and future prospects for international costsharing of…

Congress of the U.S., Washington, DC. House Committee on Science and Technology.

358

Elementary Implantable Force Sensor  

PubMed Central

Implementing implantable sensors which are robust enough to maintain long term functionality inside the body remains a significant challenge. The ideal implantable sensing system is one which is simple and robust; free from batteries, telemetry, and complex electronics. We have developed an elementary implantable sensor for orthopaedic smart implants. The sensor requires no telemetry and no batteries to communicate wirelessly. It has no on-board signal conditioning electronics. The sensor itself has no electrical connections and thus does not require a hermetic package. The sensor is an elementary L-C resonator which can function as a simple force transducer by using a solid dielectric material of known stiffness between two parallel Archimedean coils. The operating characteristics of the sensors are predicted using a simplified, lumped circuit model. We have demonstrated sensor functionality both in air and in saline. Our preliminary data indicate that the sensor can be reasonably well modeled as a lumped circuit to predict its response to loading. PMID:24883335

Wachs, Rebecca A.; Ellstein, David; Drazan, John; Healey, Colleen P.; Uhl, Richard L.; Connor, Kenneth A.

2014-01-01

359

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

360

Bacterial adhesion force quantification by fluidic force microscopy  

NASA Astrophysics Data System (ADS)

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.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. Electronic supplementary information (ESI) available: Video S1. Detachment of a S. pyogenes cell chain from glass substrate. The cantilever is approached on the outermost adherent cell of a chain and four bacteria were then sequentially detached. The sequential cell detachment suddenly stopped after four bacteria. This possibly occurred because bacteria-glass interactions became too strong or the maximal probe retraction was reached. The cells spontaneously detached from the cantilever flipping back on the surface. Fig. S1. (A) Adhesion force-distance and (B) adhesion force-detaching work correlation of E.coli on PLL for setpoints of 1 and 10 nN. Circle: 1 nN setpoint, square: 10 nN. See DOI: 10.1039/c4nr06495j

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

2015-02-01

361

Modeling and estimation of internal friction in cloth  

E-print Network

Force-deformation measurements of cloth exhibit significant hysteresis, and many researchers have identified internal friction as the source of this effect. However, it has not been incorporated into computer animation ...

Miguel, Eder

362

Are Mathematics and Science Test Scores Good Indicators of Labor-Force Quality?  

ERIC Educational Resources Information Center

Using data from the Programme for International Student Assessment (PISA) and the Trends in International Mathematics and Science Study (TIMSS), we investigate the link between test scores (mathematics and science) and cross-country income differences. We would like to know whether test scores are good indicators of labor-force quality. The…

Chen, Shiu-Sheng; Luoh, Ming-Ching

2010-01-01

363

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

364

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, DNA–protein 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

365

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.

366

Internal shim  

DOEpatents

An internal shim used to accurately measure spaces in conjunction with a standard small probe has a shim top and a chassis. The internal shim is adjustably fixed within the space to be measured using grippers that emerge from the chassis and which are controlled by an arm pivotably attached to the shim top. A standard small probe passes through the shim along guides on the chassis and measures the distance between the exterior of the chassis and the boundary. By summing the measurements on each side of the chassis and the width of the chassis, the dimension of the space can be determined to within 0.001 inches.

Barth, Clyde H.; Blizinski, Theodore W.

2003-05-13

367

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

368

International Human Rights Law: An Introduction  

Microsoft Academic Search

For more than half a century, the world community has sought to codify a series of fundamental precepts intended to prevent such abuses of human rights as torture, discrimination, starvation, and forced eviction. The United Nations, other international organizations, regional institutions, and governments have developed various procedures for protecting against and providing remedies for human rights violations.\\u000aInternational Human Rights

Connie de la Vega; David S. Weissbrodt

2007-01-01

369

Internal friction of hydroxyapatite and fluorapatite  

Microsoft Academic Search

Internal friction was measured by a forced torsional vibration method at 0.1–10Hz in the temperature range of ?100 to 400°C on both hydroxyapatite (HAp) sintered at 1300°C for 3h under fluent H2O vapor and fluorapatite (FAp) sintered at 1200°C for 3h in the F2 atmosphere. Three peaks of internal friction appeared at approximately ?40, 80 and 130°C for HAp. However,

Suguru Suzuki; Masahiro Sakamura; Masayuki Ichiyanagi; Masakuni Ozawa

2004-01-01

370

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

371

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

372

How Does Force Affect Motion?  

ERIC Educational Resources Information Center

Whether playing soccer at recess, walking to lunch, or sitting at their desk, children encounter forces every moment of their lives. The connection between force and motion is absolutely amazing to children, so anyone working with them better be prepared for the battery of tough questions they ask: "What made the ball move that way? Why does a…

Darling, Gerald

2012-01-01

373

The Forced Hard Spring Equation  

ERIC Educational Resources Information Center

Through numerical investigations, various examples of the Duffing type forced spring equation with epsilon positive, are studied. Since [epsilon] is positive, all solutions to the associated homogeneous equation are periodic and the same is true with the forcing applied. The damped equation exhibits steady state trajectories with the interesting…

Fay, Temple H.

2006-01-01

374

Observations on Police Deadly Force  

Microsoft Academic Search

Until recently, there existed little empirical research into use of deadly force by American police. Over the past several years, however, considerable study of police deadly force and police shooting has occurred. Questions raised by the body of literature involve the reasonableness of the common-law rule that police may shoot any fleeing felony suspect, and the effects of that rule

James J. Fyfe

1981-01-01

375

Force optimized recoil control system  

NASA Astrophysics Data System (ADS)

Reduction of the recoil force of high rate of fire automatic guns was proven effective. This system will allow consideration of more powerful guns for use in both helicopter and armored personnel carrier applications. By substituting the large shock loads of firing guns with a nearly constant force, both vibration and fatigue problems that prevent mounting of powerful automatic guns is eliminated.

Townsend, P. E.; Radkiewicz, R. J.; Gartner, R. F.

1982-05-01

376

Intermolecular Forces: Solids and Liquids  

NSDL National Science Digital Library

General chemistry WebCT exam/quiz questions. The Intermolecular Forces: Solids and Liquids topic covers the forces that exist between atoms and molecules in solids and liquids, and how these affect properties such as boiling point, conductivity, and lattice energy.

377

Internet Engineering Task Force INTERNETDRAFT  

E-print Network

] Internet New York ITG L.A. ITG Figure 1: Internet Telephony Gateway In this application, the InternetInternet Engineering Task Force INTERNET­DRAFT Audio­Video Transport Working Group J. Rosenberg is an Internet­Draft. Internet­Drafts are working documents of the Internet Engineering Task Force (IETF), its

Schulzrinne, Henning

378

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

379

Report of the Fermilab ILC Citizens' Task Force  

SciTech Connect

Fermi National Accelerator Laboratory convened the ILC Citizens' Task Force to provide guidance and advice to the laboratory to ensure that community concerns and ideas are included in all public aspects of planning and design for a proposed future accelerator, the International Linear Collider. In this report, the members of the Task Force describe the process they used to gather and analyze information on all aspects of the proposed accelerator and its potential location at Fermilab in northern Illinois. They present the conclusions and recommendations they reached as a result of the learning process and their subsequent discussions and deliberations. While the Task Force was charged to provide guidance on the ILC, it became clear during the process that the high cost of the proposed accelerator made a near-term start for the project at Fermilab unlikely. Nevertheless, based on a year of extensive learning and dialogue, the Task Force developed a series of recommendations for Fermilab to consider as the laboratory develops all successor projects to the Tevatron. The Task Force recognizes that bringing a next-generation particle physics project to Fermilab will require both a large international effort and the support of the local community. While the Task Force developed its recommendations in response to the parameters of a future ILC, the principles they set forth apply directly to any large project that may be conceived at Fermilab, or at other laboratories, in the future. With this report, the Task Force fulfills its task of guiding Fermilab from the perspective of the local community on how to move forward with a large-scale project while building positive relationships with surrounding communities. The report summarizes the benefits, concerns and potential impacts of bringing a large-scale scientific project to northern Illinois.

None

2008-06-01

380

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. 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 motion 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 (nonradial) force, Curie s law and the Langevin-Debye equation.

Roos, Nico

2013-01-01

381

Gene regulation by mechanical forces  

NASA Technical Reports Server (NTRS)

Endothelial cells are subjected to various mechanical forces in vivo from the flow of blood across the luminal surface of the blood vessel. The purpose of this review was to examine the data available on how these mechanical forces, in particular cyclic strain, affect the expression and regulation of endothelial cell function. Studies from various investigators using models of cyclic strain in vitro have shown that various vasoactive mediators such as nitric oxide and prostacyclin are induced by the effect of mechanical deformation, and that the expression of these mediators may be regulated at the transcription level by mechanical forces. There also seems to be emerging evidence that endothelial cells may also act as mechanotransducers, whereby the transmission of external forces induces various cytoskeletal changes and second messenger cascades. Furthermore, it seems these forces may act on specific response elements of promoter genes.

Oluwole, B. O.; Du, W.; Mills, I.; Sumpio, B. E.

1997-01-01

382

75 FR 78754 - Bureau of International Labor Affairs; Notice of Publication of 2010 Update to the Department of...  

Federal Register 2010, 2011, 2012, 2013, 2014

...public the List pursuant to the Trafficking Victims Protection Reauthorization...Child Labor, Forced Labor, and Human Trafficking, Bureau of International Labor...Child Labor, Forced Labor, and Human Trafficking (OCFT) carries out the...

2010-12-16

383

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

384

International Entomology  

Technology Transfer Automated Retrieval System (TEKTRAN)

Pests and diseases of plants in agriculture are a shared international problem. Yet some of the very places that pest invaders come from often lack the institutional structure and organization necessary to help in understanding the biology of the pest or disease. Strengthening entomology by stimulat...

385

INTERNATIONAL CHOICESREASONS  

E-print Network

University of Worcester College Finland 2 universities France 208 universities Germany 7 universities Hungary Sabio Fundación Estema Universidad de Alicante Sweden Högskolan I Skövde Jönköping International School home a new person." Frances Badjik-Bova 4th year Education South Africa I t's essential to plan ahead

386

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

387

Fulbright Internationalism  

Microsoft Academic Search

In 1946 Senator J. William Fulbright introduced and guided through Congress legislation establishing an international exchange pro gram in education. The Fulbright program, which has produced the largest migration of students and scholars in modern history, was the result first of the senator's personal experience. His goal was to make available to thousands the enlightening experience of foreign study and

Randall Bennett Woods

1987-01-01

388

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

389

Indonesia: Internal Conditions, the Global Economy, and Regional Development.  

ERIC Educational Resources Information Center

Describes recent trends in the economic and regional development of Indonesia and examines the internal and external forces influencing the process. Shows how these forces account for the rise of a strong centralized state. Discusses Indonesia's current problems. Includes tables, maps, and graphs of economic investment figures, world trade, and…

Leitner, Helga; Sheppard, Eric S.

1987-01-01

390

Collective coordinates and an accompanying metric force in structural isomerization dynamics of molecules  

NASA Astrophysics Data System (ADS)

Structural isomerization dynamics of three- and four-atom clusters of vanishing total angular momentum is studied in terms of internal coordinates of n-body systems on the basis of a gauge theory. The so-called principal-axis hyperspherical coordinates are employed effectively as collective variables for the study of isomerization reactions. It turns out that the non-Euclidean metric on the internal space gives rise to a force, which works in response to internal motions called the democratic (kinematic) rotations in the internal space. This metric force generally tends to induce an asymmetry in mass balance of a system, and is coupled with the usual potential force to give rise to trapped motions in the vicinity of the transition states of the cluster. This observation provides a different perspective for the so-called recrossing problem in chemical reaction dynamics.

Yanao, Tomohiro; Takatsuka, Kazuo

2003-09-01

391

Experimental Investigation of Forces Produced by Misaligned Steel Rollers  

NASA Technical Reports Server (NTRS)

The International Space Station Solar Alpha Rotary Joint (SARJ) uses a roller-based mechanism for positioning of the solar arrays. The forces and moments that develop at the roller interfaces are influenced by the design including the kinematic constraints and the lubrication condition. To help understand the SARJ operation, a set of dedicated experiments were completed using roller pairs. Of primary interest was to measure the axial force directed along the axis of rotation of the roller as a function of shaft misalignment. The conditions studied included dry and clean surfaces; one surface plated by a gold film, and greased surfaces. For the case of a bare 440C roller against a nitrided 15-5 roller without lubrication, the axial force can be as great as 0.4 times the normal load for a shaft angle of 0.5 degree. Such a magnitude of force on a roller in the SARJ mechanism would cause roller tipping and contact pressures much greater than anticipated by the designers. For the case of a bare 440C roller against a nitrided 15-5 roller with grease lubrication, the axial force does not exceed about 0.15 times the normal load even for the largest misalignment angles tested. Gold films provided good lubrication for the short duration testing reported herein. Grease lubrication limited the magnitude of the axial force to even smaller magnitudes than was achieved with the gold films. The experiments demonstrate the critical role of good lubrication for the SARJ mechanism.

Krantz, Timothy; DellaCorte, Christopher; Dube, Michael

2010-01-01

392

Experimental Investigation of Forces Produced by Misaligned Steel Rollers  

NASA Technical Reports Server (NTRS)

The International Space Station (ISS) Solar Alpha Rotary Joint (SARJ) uses a roller-based mechanism for positioning of the solar arrays. The forces and moments that develop at the roller interfaces are influenced by the design including the kinematic constraints and the lubrication condition. To help understand the SARJ operation, a set of dedicated experiments were completed using roller pairs. Of primary interest was to measure the axial force directed along the axis of rotation of the roller as a function of shaft misalignment. The conditions studied included dry and clean surfaces; one surface plated by a gold film, and greased surfaces. For the case of a bare 440C roller against a nitrided 15-5 roller without lubrication, the axial force can be as great as 0.4 times the normal load for a shaft angle of 0.5 deg. Such a magnitude of force on a roller in the SARJ mechanism would cause roller tipping and contact pressures much greater than anticipated by the designers. For the case of a bare 440C roller against a nitrided 15-5 roller with grease lubrication, the axial force does not exceed about 0.15 times the normal load even for the largest misalignment angles tested. Gold films provided good lubrication for the short duration testing reported herein. Grease lubrication limited the magnitude of the axial force to even smaller magnitudes than was achieved with the gold films. The experiments demonstrate the critical role of good lubrication for the SARJ mechanism.

Krantz, Timothy; DellaCorte, Christopher; Dube, Michael

2010-01-01

393

Self-forces from generalized Killing fields  

NASA Astrophysics Data System (ADS)

A non-perturbative formalism is developed that simplifies the understanding of self-forces and self-torques acting on extended scalar charges in curved spacetimes. Laws of motion are locally derived using momenta generated by a set of generalized Killing fields. Self-interactions that may be interpreted as arising from the details of a body's internal structure are shown to have very simple geometric and physical interpretations. Certain modifications to the usual definition for a center-of-mass are identified that significantly simplify the motions of charges with strong self-fields. A derivation is also provided for a generalized form of the Detweiler Whiting axiom that pointlike charges should react only to the so-called regular component of their self-field. Standard results are shown to be recovered for sufficiently small charge distributions.

Harte, Abraham I.

2008-12-01

394

Force reconstruction from tapping mode force microscopy experiments.  

PubMed

Fast, accurate, and robust nanomechanical measurements are intensely studied in materials science, applied physics, and molecular biology. Amplitude modulation force microscopy (tapping mode) is the most established nanoscale characterization technique of surfaces for air and liquid environments. However, its quantitative capabilities lag behind its high spatial resolution and robustness. We develop a general method to transform the observables into quantitative force measurements. The force reconstruction algorithm has been deduced on the assumption that the observables (amplitude and phase shift) are slowly varying functions of the tip-surface separation. The accuracy and applicability of the method is validated by numerical simulations and experiments. The method is valid for liquid and air environments, small and large free amplitudes, compliant and rigid materials, and conservative and non-conservative forces. PMID:25876817

Payam, Amir F; Martin-Jimenez, Daniel; Garcia, Ricardo

2015-05-01

395

Forces on the Human Molecule  

NSDL National Science Digital Library

In this physical activity, two lines of learners link hands and arms to model a beam subject to various loading schemes. They discover how inter-atomic forces react to the five fundamental load types that can act on structures: tension, compression, shear, bending, and torsion. This activity can be used as an introduction to these forces or as review. Note: The description refers to learners as "molecules of steel" and their arms being the bonds between them. Since steel is an alloy of multiple elements, each learner would represent an atom and their arms are the inter-atomic forces which join them.

Worcester Polytechnic Institute

2013-01-01

396

Calibration of frictional forces in atomic force microscopy  

SciTech Connect

The atomic force microscope can provide information on the atomic-level frictional properties of surfaces, but reproducible quantitative measurements are difficult to obtain. Parameters that are either unknown or difficult to precisely measure include the normal and lateral cantilever force constants (particularly with microfabricated cantilevers), the tip height, the deflection sensor response, and the tip structure and composition at the tip-surface contact. We present an {ital in} {ital situ} experimental procedure to determine the response of a cantilever to lateral forces in terms of its normal force response. This procedure is quite general. It will work with any type of deflection sensor and does not require the knowledge or direct measurement of the lever dimensions or the tip height. In addition, the shape of the tip apex can be determined. We also discuss a number of specific issues related to force and friction measurements using optical lever deflection sensing. We present experimental results on the lateral force response of commercially available V-shaped cantilevers. Our results are consistent with estimates of lever mechanical properties using continuum elasticity theory. {copyright} {ital 1996 American Institute of Physics.}

Ogletree, D.F.; Carpick, R.W.; Salmeron, M. [Materials Sciences Division, Lawrence Berkeley National Laboratory, Berkeley, California 94720 (United States)] [Materials Sciences Division, Lawrence Berkeley National Laboratory, Berkeley, California 94720 (United States)

1996-09-01

397

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.

398

Webb Model of Nuclear Structure and Forces  

NASA Astrophysics Data System (ADS)

String theory has established that neutrons and protons consist of threesomes of string-like quarks. These threesomes nucleosynthesize to build larger nuclei. This Webb Model differs by postulating that the larger nuclei are also threesomes: threesomes of string-like ring shaped Jumbo Quarks. A threesome of Jumbo Quarks make up every larger nucleus. From this starting point, the Webb Model uses only the forces of gravity and electromagnetics to accurately calculate a large variety of nuclear properties including - fundamental structural shapes and charge arrangements - the size, shape, internal forces and relativistic mass energies of the neutron, proton, deuteron, triton, alpha particle and oxygen - the details of all types of beta decay - the correct slope of the lower end of the nuclear chart - the calculated stability of the 45 smallest stable nuclei and their 59 naturally occurring unstable isotopes - and mathematical confirmation of the magic number 2,8 and 20. This Webb model satisfies the empirical tests of the Scientific Method. The mathematics is simple enough to be confirmed by any scientist without bias.

Webb, Bill

2008-10-01

399

Internal Flow  

NASA Astrophysics Data System (ADS)

Focusing on phenomena important in implementing the performance of a broad range of fluid devices, this work describes the behavior of internal flows encountered in propulsion systems, fluid machinery (compressors, turbines, and pumps) and ducts (diffusers, nozzles and combustion chambers). The book equips students and practicing engineers with a range of new analytical tools. These tools offer enhanced interpretation and application of both experimental measurements and the computational procedures that characterize modern fluids engineering.

Greitzer, E. M.; Tan, C. S.; Graf, M. B.

2004-06-01

400

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.

401

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

402

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

403

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

404

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.

405

Forces Applied by Cilia Measured on Explants from Mucociliary Tissue  

PubMed Central

Forces applied by intact mucus-propelling cilia were measured for the first time that we know of using a combined atomic force microscopy (AFM) and electrooptic system. The AFM probe was dipped into a field of beating cilia and its time-dependent deflection was recorded as it was struck by the cilia while the electrooptic system simultaneously and colocally measured the frequency to ensure that no perturbation was induced by the AFM probe. Using cilia from frog esophagus, we measured forces of ?0.21 nN per cilium during the effective stroke. This value, together with the known internal structure of these cilia, leads to the conclusion that most dynein arms along the length of the axoneme contribute to the effective stroke of these cilia. PMID:17142280

Teff, Zvi; Priel, Zvi; Gheber, Levi A.

2007-01-01

406

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

407

Force Measurement Device for ARIANE 5 Payloads  

Microsoft Academic Search

ESTEC uses since 1991 a Force Measurement Device (FMD) for the measurement of dynamic mechanical forces and moments. This tool allows the determination of forces and moments applied to the test hardware at its interface to the test facilities during dynamic testing. Three forces and three moments are calculated from the measurements of eight tri-axial force links and used to

O. Brunner; R. Braeken

2004-01-01

408

A tense situation: forcing tumour progression  

Microsoft Academic Search

Cells within tissues are continuously exposed to physical forces including hydrostatic pressure, shear stress, and compression and tension forces. Cells dynamically adapt to force by modifying their behaviour and remodelling their microenvironment. They also sense these forces through mechanoreceptors and respond by exerting reciprocal actomyosin- and cytoskeletal-dependent cell-generated force by a process termed 'mechanoreciprocity'. Loss of mechanoreciprocity has been shown

Darci T. Butcher; Tamara Alliston; Valerie M. Weaver

2009-01-01

409

Relativistic force and the anisotropy of mass  

Microsoft Academic Search

A new force definition is derived which permits a more reasonable description of the nature of centripetal or transverse forces. It has separate expressions for the tangential and normal components of force. Concomitant with this new force definition, a particle that moves normal to the accelerating force has an increased inertia as manifested by its acceleration. That particle can be

ARTHUR L. Lathrop

1997-01-01

410

Fluorescence-force spectroscopy at the single molecule level  

NASA Astrophysics Data System (ADS)

During the past decade, various powerful single-molecule techniques have evolved and helped to address important questions in life sciences. As the single molecule techniques become mature, there is increasingly pressing need to maximize the information content of the analysis in order to be able to study more complex systems that better approximate in-vivo conditions. Here, we develop a fluorescence-force spectroscopy method to combine single-molecule fluorescence spectroscopy with optical tweezers. Optical tweezers are used to manipulate and observe mechanical properties on the nanometer scale and piconewton force range. However, once the force range is in the low piconewton range or less, the spatial resolution of optical tweezers decreases significantly. In combination with fluorescence spectroscopy, like single molecule Forster (or fluorescence) resonance energy transfer (FRET) whose detectable distance range is approximately 3-10 nm, we are able to observe nanometer fluctuations and internal conformational changes in a low-force regime. The possibility to place fluorescent labels at nearly any desired position and a sophisticated design of the experiment increases the amount of information that can be extracted in contrast to pure mechanical or fluorescence experiments. We demonstrate the applications of this method to various biological systems including: 1) to measure the effect of very low forces on the nanometer scale conformational transitions of the DNA four-way (Holliday) junction; 2) to dissect protein diffusion and dissociation mechanisms on single stranded DNA, 3) to calibrate FRET-based in-vivo force sensors and 4) to study mechanical unfolding of single proteins. The results could not have been obtained with fluorescence or force measurement alone, and clearly demonstrates the power and generality of our approach. Finally, we show that self-quenching of two identical fluorophores can be used to detect small conformational dynamics corresponding to sub-nanometer distance changes of single molecules in a FRET-insensitive short range (< 3 nm), extending the detectable distance range of our fluorescence-force spectroscopy method.

Zhou, Ruobo

411

Increasing Running Step Rate Reduces Patellofemoral Joint Forces  

PubMed Central

Purpose Increasing step rate has been shown to elicit changes in joint kinematics and kinetics during running, and has been suggested as a possible rehabilitation strategy for runners with patellofemoral pain. The purpose of this study was to determine how altering step rate affects internal muscle forces and patellofemoral joint loads, and then to determine what kinematic and kinetic factors best predict changes in joint loading. Methods We recorded whole body kinematics of 30 healthy adults running on an instrumented treadmill at three step rate conditions (90%, 100%, and 110% of preferred step rate). We then used a 3D lower extremity musculoskeletal model to estimate muscle, patellar tendon, and patellofemoral joint forces throughout the running gait cycles. Additionally, linear regression analysis allowed us to ascertain the relative influence of limb posture and external loads on patellofemoral joint force. Results Increasing step rate to 110% of preferred reduced peak patellofemoral joint force by 14%. Peak muscle forces were also altered as a result of the increased step rate with hip, knee and ankle extensor forces, and hip abductor forces all reduced in mid-stance. Compared to the 90% step rate condition, there was a concomitant increase in peak rectus femoris and hamstring loads during early and late swing, respectively, at higher step rates. Peak stance phase knee flexion decreased with increasing step rate, and was found to be the most important predictor of the reduction in patellofemoral joint loading. Conclusion Increasing step rate is an effective strategy to reduce patellofemoral joint forces and could be effective in modulating biomechanical factors that can contribute to patellofemoral pain. PMID:23917470

Lenhart, Rachel L.; Thelen, Darryl G.; Wille, Christa M.; Chumanov, Elizabeth S.; Heiderscheit, Bryan C.

2013-01-01

412

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

413

Physlet Force Concept Inventory: Gravity  

NSDL National Science Digital Library

A boy throws a steel ball straight up. Consider the motion of the ball only after it has left the boy's hand but before it touches the ground, and assume that the forces exerted by the air are negligible.

Wolfgang Christian

414

A Graphene Surface Force Balance  

PubMed Central

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 cm2). 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

2014-01-01

415

Molecular force spectroscopy on cells.  

PubMed

Molecular force spectroscopy has become a powerful tool to study how mechanics regulates biology, especially the mechanical regulation of molecular interactions and its impact on cellular functions. This force-driven methodology has uncovered a wealth of new information of the physical chemistry of molecular bonds for various biological systems. The new concepts, qualitative and quantitative measures describing bond behavior under force, and structural bases underlying these phenomena have substantially advanced our fundamental understanding of the inner workings of biological systems from the nanoscale (molecule) to the microscale (cell), elucidated basic molecular mechanisms of a wide range of important biological processes, and provided opportunities for engineering applications. Here, we review major force spectroscopic assays, conceptual developments of mechanically regulated kinetics of molecular interactions, and their biological relevance. We also present current challenges and highlight future directions. PMID:25580628

Liu, Baoyu; Chen, Wei; Zhu, Cheng

2015-04-01

416

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

417

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.

418

Air Force Research Laboratory AFRLAir Force Research Laboratory AFRL Science and Technology for Tomorrow's Air and Space Force  

E-print Network

JAV Air Force Research Laboratory AFRLAir Force Research Laboratory AFRL Science and Technology activities in the Air Force Research Laboratory, contact TECH CONNECT, AFRL/XPTC, (800) 203-6451 and you

Deloach, Scott A.

419

Domestic Constraints and International Forces: Exploring China's Position on International Climate Change Policy  

Microsoft Academic Search

China can be characterized as the key actor in solving the global climate change problem because of the size of its GHG-emissions. Currently it is the second largest emitter of gases causing global warming after the United States. In addition, China has a big influence in climate change negotiations due to its position in the Group of 77 states (G77).

Yang Yi

420

COOLING FORCE MEASUREMENTS IN CELSIUS.  

SciTech Connect

The design of future high energy coolers relies heavily on extending the results of cooling force measurements into new regimes by using simulation codes. In order to carefully benchmark these codes we have accurately measured the longitudinal friction force in CELSIUS by recording the phase shift between the beam and the RF voltage while varying the RF frequency. Moreover, parameter dependencies on the electron current, solenoid magnetic field and magnetic field alignment were carried out.

GALNANDER, B.; FEDOTOV, A.V.; LITVINENKO, V.N.; ET AL.

2005-09-18

421

Electrostatic forces for personnel restraints  

NASA Technical Reports Server (NTRS)

The feasibility of utilizing electrostatic forces for personnel retention devices on exterior spacecraft surfaces was analyzed. The investigation covered: (1) determination of the state of the art; (2) analysis of potential adhesion surfaces; (3) safety considerations for personnel; (4) electromagnetic force field determination and its effect on spacecraft instrumentation; and (5) proposed advances to current technology based on documentation review, analyses, and experimental test data.

Ashby, N.; Ciciora, J.; Gardner, R.; Porter, K.

1977-01-01

422

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.

423

International Education Hubs: Collaboration for Competitiveness and Sustainability  

ERIC Educational Resources Information Center

This chapter focuses on the development of education hubs, a recent phenomenon in international higher education. Three models of hubs are examined in relation to the forces, risks, and opportunities of globalization and how local and international collaborations are essential for both global competitiveness and sustainability.

Knight, Jane

2014-01-01

424

International women's magazines in China: Global and local perspectives  

Microsoft Academic Search

Unlike other global media products that are imported from overseas, international women's magazines in China are published via licensing agreements or joint ventures with local companies. These ownership patterns allow local editions of international women's magazines to negotiate the tensions and contradictions between the global players and local publishers. Given the influence of cultural and commercial forces in different economic

Kavita Karan; Yang Feng

2009-01-01

425

Developing Curriculum: Knowledge and Skills Essential for an International Salesforce.  

ERIC Educational Resources Information Center

A study explored the additional knowledge and skills an international salesforce needs based upon 95 respondents from Wisconsin manufacturing companies. Six areas were evaluated by sales representatives involved with international sales and marketing to identify the education and training needed within the next 3 years by the work force. Four…

Ruhland, Sheila K.

426

Improving the Delivery of the Undergraduate International Business Course.  

ERIC Educational Resources Information Center

The components of an undergraduate international business (IB) course, developed and taught according to corporate suggestions, are correlated with the importance ascribed to them by students taking the class. Students felt all 21 components should be emphasized, especially the sociocultural/political/legal forces in IB, international finance, and…

Thanopoulos, John; And Others

1995-01-01

427

Is Gravity an Entropic Force?  

E-print Network

The remarkable connections between gravity and thermodynamics seem to imply that gravity is not fundamental but emergent, and in particular, as Verlinde suggested, gravity is probably an entropic force. In this paper, we will argue that the idea of gravity as an entropic force is debatable. It is shown that there is no convincing analogy between gravity and entropic force in Verlinde's example. Neither holographic screen nor test particle satisfies all requirements for the existence of entropic force in a thermodynamics system. Furthermore, we show that the entropy increase of the screen is not caused by its statistical tendency to increase entropy as required by the existence of entropic force, but in fact caused by gravity. Therefore, Verlinde's argument for the entropic origin of gravity is problematic. In addition, we argue that the existence of a minimum size of spacetime, together with the Heisenberg uncertainty principle in quantum theory, may imply the fundamental existence of gravity as a geometric property of spacetime. This may provide a further support for the conclusion that gravity is not an entropic force.

Shan Gao

2011-07-16

428

Casimir forces beyond the proximity approximation  

E-print Network

The proximity force approximation (PFA) relates the interaction between closely spaced, smoothly curved objects to the force between parallel plates. Precision experiments on Casimir forces necessitate, and spur research ...

Bimonte, G.

429

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.

430

Defining International Education.  

ERIC Educational Resources Information Center

Discusses the three facets of international education: international studies, international education exchange, and technical assistance. Also explores the effects of internationalizing higher education and the present state of international education. (EV)

Hansen, Holly Moran

2002-01-01

431

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 N·s/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

432

ACCION International  

NSDL National Science Digital Library

Part of the ongoing debate about the process of globalization throughout both the developed and developing world is that a good deal of the world's population continues to grow poorer and poorer while a number of international transnational corporations continue to increase their share of the world's assets. There have been a number of efforts to combat poverty in the developing world, including the highly publicized and generally well-received efforts of the Grameen Bank in Bangladesh. One such nonprofit program that has successfully been transplanted from the developing world to the developed world is the ACCION International program of microlending. On its homepage, visitors can learn about the organization's various programs designed to raise people out of poverty through microlending, and also read some key statistics behind its work. For those looking for more detailed information, there is also a publications area, where visitors may download works on topic such as the sustainability of such programs and various "how to" manuals for microentrepreneurs. Many of the publications are available at no charge, and a number of them are also available in Spanish. Finally, visitors may also sign up to receive the ACCION e-News as well.

433

Transparency International  

NSDL National Science Digital Library

With headquarters in Berlin, Transparency International (TI) is an international non-governmental organization dedicated to combating corruption in its many guises across the world. As their website notes, TI â??focuses on prevention and reforming systemsâ?. With a well-designed and rather elegant homepage, visitors will find much to admire here. The top of the homepage provides access to their â??In Focusâ? feature, which draws attention to some of TIâ??s more recent work, such as the Global Corruption Report for 2006. Below this feature, visitors will find links to recent news stories dealing with corruption, such as the recent Kenyan government scandal and anti-corruption initiatives in West Africa. Visitors can also utilize the â??Corruption: Learn About itâ? area, as it contains FAQs on corruption, and a number of indices, such as the global corruption barometer as well as a number of regional surveys. For pragmatic material, one need to look no further than their â??How to Fight Corruptionâ? section, which contains an anti-corruption handbook and a set of business principles for countering bribery.

434

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

435

Forces driving epithelial wound healing  

NASA Astrophysics Data System (ADS)

A fundamental feature of multicellular organisms is their ability to self-repair wounds through the movement of epithelial cells into the damaged area. This collective cellular movement is commonly attributed to a combination of cell crawling and `purse-string’ contraction of a supracellular actomyosin ring. Here we show by direct experimental measurement that these two mechanisms are insufficient to explain force patterns observed during wound closure. At early stages of the process, leading actin protrusions generate traction forces that point away from the wound, showing that wound closure is initially driven by cell crawling. At later stages, we observed unanticipated patterns of traction forces pointing towards the wound. Such patterns have strong force components that are both radial and tangential to the wound. We show that these force components arise from tensions transmitted by a heterogeneous actomyosin ring to the underlying substrate through focal adhesions. The structural and mechanical organization reported here provides cells with a mechanism to close the wound by cooperatively compressing the underlying substrate.

Brugués, Agustí; Anon, Ester; Conte, Vito; Veldhuis, Jim H.; Gupta, Mukund; Colombelli, Julien; Muñoz, José J.; Brodland, G. Wayne; Ladoux, Benoit; Trepat, Xavier

2014-09-01

436

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

437

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

438

Stationary Apparatus Would Apply Forces of Walking to Feet  

NASA Technical Reports Server (NTRS)

A proposed apparatus would apply controlled cyclic forces to both feet for the purpose of preventing the loss of bone density in a human subject whose bones are not subjected daily to the mechanical loads of normal activity in normal Earth gravitation. The apparatus was conceived for use by astronauts on long missions in outer space; it could also be used by bedridden patients on Earth, including patients too weak to generate the necessary forces by their own efforts. The apparatus (see figure) would be a modified version of a bicycle-like exercise machine, called the cycle ergometer with vibration isolation system (CEVIS), now aboard the International Space Station. Attached to each CEVIS pedal would be a computer-controlled stress/ vibration exciter connected to the heel portion of a special-purpose pedal. The user would wear custom shoes that would amount to standard bicycle shoes equipped with cleats for secure attachment of the balls of the feet to the special- purpose pedals. If possible, prior to use of the apparatus, the human subject would wear a portable network of recording accelerometers, while walking, jogging, and running. The information thus gathered would be fed to the computer, wherein it would be used to make the exciters apply forces and vibrations closely approximating the forces and vibrations experienced by that individual during normal exercise. It is anticipated that like the forces applied to bones during natural exercise, these artificial forces would stimulate the production of osteoblasts (bone-forming cells), as needed to prevent or retard loss of bone mass. In addition to helping to prevent deterioration of bones, the apparatus could be used in treating a person already suffering from osteoporosis. For this purpose, the magnitude of the applied forces could be reduced, if necessary, to a level at which weak hip and leg bones would still be stimulated to produce osteoblasts without exposing them to the full stresses of walking and thereby risking fracture.

Hauss, Jessica; Wood, John; Budinoff, Jason; Correia, Michael; Albrecht, Rudolf

2006-01-01

439

Match your sales force structure to your business life cycle.  

PubMed

Although companies devote considerable time and money to managing their sales forces, few focus much thought on how the structure of the sales force needs to change over the life cycle of a product or a business. However, the organization and goals of a sales operation have to evolve as businesses start up, grow, mature, and decline if a company wants to keep winning the race for customers. Specifically, firms must consider and alter four factors over time: the differing roles that internal salespeople and external selling partners should play, the size of the sales force, its degree of specialization, and how salespeople apportion their efforts among different customers, products, and activities. These variables are critical because they determine how quickly sales forces respond to market opportunities, they influence sales reps' performance, and they affect companies' revenues, costs, and profitability. In this article, the authors use timeseries data and cases to explain how, at each stage, firms can best tackle the relevant issues and get the most out of their sales forces. During start-up, smart companies focus on how big their sales staff should be and on whether they can depend upon selling partners. In the growth phase, they concentrate on getting the sales force's degree of specialization and size right. When businesses hit maturity, companies should better allocate existing resources and hire more general-purpose salespeople. Finally, as organizations go into decline, wise sales leaders reduce sales force size and use partners to keep the business afloat for as long as possible. PMID:16846191

Zoltners, Andris A; Sinha, Prabhakant; Lorimer, Sally E

2006-01-01

440

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

441

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

442

Note on forced Burgers turbulence  

SciTech Connect

A putative powerlaw range of the probability density of velocity gradient in high-Reynolds-number forced Burgers turbulence is studied. In the absence of information about shock locations, elementary conservation and stationarity relations imply that the exponent {minus}{alpha} in this range satisfies {alpha}{ge}3, if dissipation within the power-law range is due to isolated shocks. A generalized model of shock birth and growth implies {alpha}=7/2 if initial data and forcing are spatially homogeneous and obey Gaussian statistics. Arbitrary values {alpha}{ge}3 can be realized by suitably constructed homogeneous, non-Gaussian initial data and forcing. {copyright} {ital 1999 American Institute of Physics.}

Kraichnan, R.H. [PMB 108, 369 Montezuma, Santa Fe, New Mexico 87501-2626 (United States)] [PMB 108, 369 Montezuma, Santa Fe, New Mexico 87501-2626 (United States)

1999-12-01

443

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".

444

Effect of hold depth and grip technique on maximal finger forces in rock climbing.  

PubMed

The aim of this study was to understand how the commonly used climbing-specific grip techniques and hold depths influence the finger force capacities. Ten advanced climbers performed maximal voluntary force on four different hold depths (from 1 to 4 cm) and in two force directions (antero-posterior and vertical) using three grip techniques (slope, half crimp and full crimp). A specially designed platform instrumented with a 6-degrees-of-freedom (DoF) force/torque sensor was used to record force values. Results showed that the maximal vertical forces differed significantly according to the hold depth and the grip technique (ranged from 350.8 N to 575.7 N). The maximal vertical forces increased according to the hold depth but the form of this increase differed depending on grip technique. These results seemed to be more associated with finger-hold contact/interaction than with internal biomechanical factors. Similar results were revealed for antero-posterior forces (ranged from 69.9 N to 138.0 N) but, it was additionally noted that climbers have different hand-forearm posture strategies with slope and crimp grip techniques when applying antero-posterior forces. This point is important as it could influence the body position adopted during climbing according to the chosen grip technique. For trainers and designers, a polynomial regression model was proposed in order to predict the mean maximal force based on hold depth and adopted grip technique. PMID:22339482

Amca, Arif Mithat; Vigouroux, Laurent; Aritan, Serdar; Berton, Eric

2012-01-01

445

The Astronomical Forcing of Climate Change: Forcings and Feedbacks  

NASA Astrophysics Data System (ADS)

Understanding the role that orbital forcing played in driving climate change over the Pleistocene has been a matter of ongoing research. While it is undeniable that variations in Earth’s orbit result in changes in the seasonal and latitudinal distribution of insolation, the specifics of how this forcing leads to the climate changes seen in the paleo record are not fully understood. To research this further, climate simulations have been conducted with the GFDL CM2.1, a coupled atmosphere-ocean GCM. Two simulations represent the extremes of obliquity during the past 600 kyr and four others show key times in the precessional cycle. All non-orbital variables are set to preindustrial levels to isolate the effects of astronomical forcing alone. It is expected that feedbacks should play a large role in dictating climate change, so to investigate this, the so-called “kernel method” is used to calculate the lapse rate, water vapor, albedo, and cloud feedbacks. Preliminary results of these experiments confirm that feedbacks are important in explaining the nature and, in places, even the sign of climate response to orbital forcing. In the case of low obliquity, for instance, a combination of climate feedbacks lead to global cooling in spite of zero global-average top of atmosphere insolation change. Feedbacks will be analyzed in the obliquity and precession experiments so that the role of feedbacks in contributing to climate change may be better understood.

Erb, M. P.; Broccoli, A. J.; Clement, A. C.

2010-12-01

446

Intern reflections.  

PubMed

At UVA's Family Medicine Residency, 55-word stories have been incorporated into the "Resilient Practitioner Curriculum." The Resilient Practitioner Curriculum is a 3-year longitudinal curriculum developed under a HRSA grant by our Behavioral Medicine faculty to promote wellness and personal and professional growth during residency. It focuses on four broad areas of wellness: (a) Relationships (long-term attachments and daily connections); (b) Meaning (a personal philosophy of life); (c) Mastery (a sense of growing professional mastery); and (d) Health (attention to physical and mental health needs). It is hoped that writing 55-word stories will promote interns' ability to make meaning out of their experiences (Meaning), and reflective writing has been found to increase a sense of well being (Health). A few of these stories have been included. (PsycINFO Database Record (c) 2015 APA, all rights reserved). PMID:25751187

Young, Emily E; Burchett, Mary E; Cowart, Ryann; Montgomery, Cecily; Turner, Patrick L

2015-03-01

447

International Rivers  

NSDL National Science Digital Library

International Rivers is an organization that opposes the construction of destructive dams on rivers, and they also support communities affected by dams. Their aim is to "protect rivers and promote just and sustainable water and energy development." Visitors will find most of their questions about dams and hydroelectricity can be answered under the "Learn More" tab's FAQ section. Along with each answer, there is most often an article, slideshow, video or other resource to explore further. Some of the pieces examine why there is opposition to large dams, the expense of hydroelectricity, the lack of local jobs produced when a dam is being built in a developing country, and the number of people displaced by dams. Under the "Get Involved" tab, there is a section called "Tools for Educators" that include lessons for introductory learners, intermediate learners, advanced learners, and a "River Educator's Toolkit", which contains lessons on the four major rivers in Asia, Africa, and South America.

448

International Agreement on Planetary Protection  

NASA Technical Reports Server (NTRS)

The maintenance of a NASA policy, is consistent with international agreements. The planetary protection policy management in OSS, with Field Center support. The advice from internal and external advisory groups (NRC, NAC/Planetary Protection Task Force). The technology research and standards development in bioload characterization. The technology research and development in bioload reduction/sterilization. This presentation focuses on: forward contamination - research on the potential for Earth life to exist on other bodies, improved strategies for planetary navigation and collision avoidance, and improved procedures for sterile spacecraft assembly, cleaning and/or sterilization; and backward contamination - development of sample transfer and container sealing technologies for Earth return, improvement in sample return landing target assessment and navigation strategy, planning for sample hazard determination requirements and procedures, safety certification, (liaison to NEO Program Office for compositional data on small bodies), facility planning for sample recovery system, quarantine, and long-term curation of 4 returned samples.

2000-01-01

449

International Study of Arctic Change  

NASA Astrophysics Data System (ADS)

The International Study of Arctic Change (ISAC) is a long-term international research program designed to understand the future state of the Arctic System under anthropogenic stress. The driving force behind ISAC is the need to build capacity for understanding and projecting Arctic System changes so as to develop the necessary mitigation and adaptation strategies that will minimize the adverse effects of such changes. ISAC extends the study of the Arctic from basic science to offer insight into options for solutions to real world problems that are intrinsic to a changing planet. This presentation lays out the scientific and societal rational for ISAC that is more comprehensively addressed in the ISAC Draft Science Plan, and then an iterative series of implementation activities and products that will begin to realize the larger vision for ISAC.

Murray, M. S.; Tjernstrom, M. K.

2009-12-01

450

Processes of Internal and International Migration from Chitwan, Nepal  

PubMed Central

In this study we examine which factors predict internal and international migration from Chitwan, a flat valley located in the South-Central region of Nepal, seeking to measure the effect of theoretically specified variables such as human capital, social capital, physical capital, and neighborhood socioeconomic conditions while controlling for demographic variables. We use data from the Chitwan Valley Family Study (CVFS) to estimate a series of discrete time event history models of first and repeat migration to three competing destinations: other locations within Chitwan, other districts within Nepal, and places outside of Nepal. Results support hypotheses derived from neoclassical economics, the theory of new economics of migration, social capital theory, and cumulative causation theory. Our results underscore the need for a synthetic theoretical model that incorporates factors operating at the individual, household, and community levels. The use of multiple explanatory models yields a clearer picture of the forces driving internal and international migration from rural districts in developing nations such as Nepal. PMID:21423821

Bohra, Pratikshya; Massey, Douglas S.

2011-01-01

451

Casimir force on a piston  

E-print Network

We consider a massless scalar field obeying Dirichlet boundary conditions on the walls of a two-dimensional L x b rectangular box, divided by a movable partition (piston) into two compartments of dimensions a x b and (L-a) x b. We compute the Casimir force on the piston in the limit L -> infinity. Regardless of the value of a/b, the piston is attracted to the nearest end of the box. Asymptotic expressions for the Casimir force on the piston are derived for a > b.

R. M. Cavalcanti

2004-01-26

452

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

453

Iterated Forcing and Elementary Embeddings  

Microsoft Academic Search

I give a survey of some forcing techniques which are useful in the study of large cardinals and elementary embeddings. The\\u000a main theme is the problem of extending a (possibly generic) elementary embedding of the universe to a larger domain, which\\u000a is typically a generic extension of the ground model by some iterated forcing construction.\\u000a \\u000a Topics covered include\\u000a \\u000a \\u000a (a) building,

James Cummings

454

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

455

Fluid forces on circular cylinders  

E-print Network

) ~ the earliest aetbod of aasressing the force cn s cylinder due to a fluid in Ae unsteady cm&ition bss been to consider the total fluid fern? cca- possd of two ceqpcaamts~ (l) a drag force caayonsmt end (2) en inertial f ores cce@m~t. FT + FD + FJ, ~ ~ p... ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ o {)) dp where D is the cy11ndsr disaster and 4 ths subaerged depth of the cylinder. For a circular cylinder, the drag coefficientv C? hss been successfully related to the Reynold's number, [R] as shown in Figure l. ~ . ~. . . . . ~. . . ~ R...

Dean, Robert G

1956-01-01

456

Population commission discusses international migration.  

PubMed

At the 30th session of the Commission on Population and Development during February 24-28, 1997, international migration was the main topic, with special linkages between migration and development and on gender issues and the family. New and emerging issues were also considered. Members stressed the need for more reliable data on migration, the direction of migrants flows, and the characteristics of migrants. The Commission requested a task force on basic social services to hold a technical symposium of experts on international migration in 1998. Its chair, Dr. Nafis Sadik, said that migration issues should based on the reality of choice not on coercive measures or quotas. Almost half of the migrants globally are women. The Commission was given a new impetus by the International Conference on Population and Development held at Cairo in 1994. Migration pressures intensified in the second half of the 1980s and in the early 1990s, creating areas of concern: the negative impact of short-term migration on working conditions in host countries; migration pressures emanating from climatic change; the protection of migrant women and their children; the right of receiving countries to regulate access to their territory; the adverse consequences of forced migration; the situation of persons whose asylum claims have been rejected; the trafficking in women and children, prostitution and coercive adoption; and the sudden and massive arrival of refugees in need of international protection. The 1998 session of the Commission will feature the theme of health and mortality, with special emphasis on the linkages between health and development and on gender and age. PMID:12292475

1997-01-01

457

Surface manifestation of internal tides in the deep ocean: observations from altimetry and island gauges  

Microsoft Academic Search

The sea-surface height signatures of internal tides in the deep ocean, amounting to a few centimeters or less, are studied using two complementary measurement types: satellite altimetry and island tide gauges. Altimetry can detect internal tides that maintain coherence with the astronomical forcing; island gauges can monitor temporal variability which, in some circumstances, is due to internal tides varying in

Richard D. Ray; Gary T. Mitchum

1997-01-01

458

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

459

Dynamic Force Spectroscopy of Single DNA Molecules  

Microsoft Academic Search

To explore the analytic relevance of unbinding force measurements between complementary DNA strands with an atomic force microscope, we measured the forces to mechanically separate a single DNA duplex under physiological conditions by pulling at the opposite 5'-ends as a function of the loading rate (dynamic force spectroscopy). We investigated DNA duplexes with 10, 20, and 30 base pairs with

Torsten Strunz; Krisztina Oroszlan; Rolf Schafer; Hans-Joachim Guntherodt

1999-01-01

460

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

461

Trajectory control in targeted force impulses  

Microsoft Academic Search

The functional role of opposing muscles in the production of isometric force trajectories was studied in six adult subjects producing impulses and steps of elbow flexor force, with different rise times and amplitudes. Rapidly rising forces were invariably associated with an alternating pattern of EMG activity in agonist and antagonist muscles: an agonist burst (AGI) initiated the development of force

C. Ghez; J. Gordon

1987-01-01

462

Force Controllable Hydro-Elastic Actuator  

Microsoft Academic Search

We present a hydro-elastic actuator that has a linear spring intentionally placed in series between the hydraulic piston and actuator output. The spring strain is measured to get an accurate estimate of force. This measurement alone is used in PI feedback to con- trol the force in the actuator. The spring allows for high force delity, good force control, minimum

David W. Robinson; Gill A. Pratt

2000-01-01

463

Titan Tusk Force Student Engagement Report  

E-print Network

Titan Tusk Force Student Engagement Report FY 2009-2010 Mission Statement The mission of Titan Tusk Force is to develop a strong sense of campus unity, pride and identity with CSUF. Titan Tusk Force, Incorporated here at California State University, Fullerton. Program Overview Titan Tusk Force (TTF) functions

de Lijser, Peter

464

Titan Tusk Force Student Engagement Report  

E-print Network

Titan Tusk Force Student Engagement Report FY 2010-2011 Mission Statement The mission of Titan Tusk Force is to develop a strong sense of campus unity, pride and identity with CSUF. Titan Tusk Force, Incorporated here at California State University, Fullerton. Program Overview Titan Tusk Force (TTF) functions

de Lijser, Peter

465

Titan Tusk Force Student Engagement Report  

E-print Network

Titan Tusk Force Student Engagement Report FY 2008-2009 Mission Statement The mission of Titan Tusk Force is to develop a strong sense of campus unity, pride and identity with CSUF. Titan Tusk Force, Incorporated here at California State University, Fullerton. Program Overview Titan Tusk Force (TTF) functions

de Lijser, Peter

466

Titan Tusk Force Student Engagement Report  

E-print Network

Titan Tusk Force Student Engagement Report FY 2012-2013 Mission Statement The mission of Titan Tusk Force is to develop a strong sense of campus unity, pride and identity with CSUF. Titan Tusk Force, CSUF, Incorporated here at California State University, Fullerton. Program Overview Titan Tusk Force

de Lijser, Peter

467

Titan Tusk Force Student Engagement Report  

E-print Network

Titan Tusk Force Student Engagement Report FY 2011-2012 Mission Statement The mission of Titan Tusk Force is to develop a strong sense of campus unity, pride and identity with CSUF. Titan Tusk Force, Incorporated here at California State University, Fullerton. Program Overview Titan Tusk Force (TTF) functions

de Lijser, Peter

468

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

469

The effect of occlusal forces on restorations.  

PubMed

This review will focus on the effect occlusal forces, both normal masticatory force and paranormal bruxing and clenching force, have on various restorative materials and their interaction with the teeth through a variety of bonding mechanisms. Salient physical properties of each of the materials will be reviewed, as well as the effect occlusal force has on restoration durability. PMID:23346657

Larson, Thomas D

2012-01-01

470

The effect of occlusal forces on restorations.  

PubMed

This review will focus on the effect occlusal forces, both normal masticatory force and paranormal bruxing and clenching force, have on various restorative materials and their interaction with the teeth through a variety of bonding mechanisms. Salient physical properties of each of the materials will be reviewed, as well as the effect occlusal force has on restoration durability. PMID:25318197

Larson, Thomas D

2014-09-01

471

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

472

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

473

A new position based force\\/impedance control for industrial robots  

Microsoft Academic Search

This paper presents a new position-based force\\/impedance control scheme which provides a feasible and reliable solution for performing contact tasks in industrial robotic systems. The control scheme consists of an outer implicit force control loop clos