Uphill falling of old-growth Douglas-fir.

Treesearch

Douglas L. Hunt; John W. Henley

1981-01-01

Five timber sales were made in old-growth Douglas-fir with matched cutting units. On one unit of each sale uphill falling by either hydraulic jacks or tree-pulling machine was required; on the other unit free falling was required. Logging equipment and methods were the same in each unit. Uphill falling produced a larger volume of timber at less cost than free falling...

Experiments in Free Fall

ERIC Educational Resources Information Center

Art, Albert

2006-01-01

A model lift containing a figure of Albert Einstein is released from the side of a tall building and its free fall is arrested by elastic ropes. This arrangement allows four simple experiments to be conducted in the lift to demonstrate the effects of free fall and show how they can lead to the concept of the equivalence of inertial and…

Effect of free fall on higher plants.

NASA Technical Reports Server (NTRS)

Gordon, S. A.

1973-01-01

The influence of exposure to the free-fall state on the orientation, morphogenesis, physiology, and radiation response of higher plants is briefly summarized. It is proposed that the duration of the space-flight experiments has been to brief to permit meaningful effects of free fall on general biochemistry, growth, and development to appear. However, two types of significant effect did occur. The first is on differential growth - i.e., tropism and epinasty - resulting from the absence of a normal geostimulus. For these phenomena it is suggested that ground-based experiments with the clinostat would suffice to mimic the effect of the free-fall state. The second is an apparent interaction between the radiation response and some flight condition, yielding an enhanced microspore abortion, a disturbed spindle function, and a stunting of stamen hairs. It is suggested that this apparent interaction may be derived from a shift in the rhythm of the cell cycle, induced by the free fall.

Research relative to the development of a cryogenic microwave cavity gradiometer for orbital use

NASA Technical Reports Server (NTRS)

Grossi, M. D.

1984-01-01

The noncryogenic, single axis, gravity gradiometer which is characterized by a sensitivity of the order of 10 to the minus 2 power Eovos Units in a few sec integration time was investigated. The prototype of testing gradiometer on the earth surface by the free fall in vacuo method was expanded. An existing free fall tower facility and the possibility of adding inside the falling elevator cabin an air tight, sealed, cylindrical container with inside pressure or = -0.001 Torr were examined to test the gradiometer in free fall conditions inside this evacuated container. Earth's gravity anomalies are simulated with masses of suitable shape, weight, and location. The attitude of the falling gradiometer is monitored by a three axis gyro package mounted on the instrument package. It is concluded that the free fall testing of the gradiometer is both feasible and practical.

The free-fall mode experiment on LISA Pathfinder: first results

NASA Astrophysics Data System (ADS)

Giusteri, Roberta; LPF Collaboration

2017-05-01

The LISA Pathfinder space mission is testing the critical experimental challenge for LISA by measuring the differential acceleration between two free-falling test masses inside a single co-orbiting spacecraft at a level of sub-femto-g for frequencies down to 0.1mHz. In LPF it is necessary that one test mass (TM) is electrostatically forced to follow the orbit of the other TM. This force represents a noise source in differential acceleration at frequencies below 1mHz. The free-fall mode experiment has been performed in order to reduce this source of noise: the actuation is limited to short impulses on one TM, so that it is in free fall between two successive kicks, while the other TM is drag-free. The free-fall mode thus provides a different technique for measuring the differential TM acceleration without the added force noise and calibration issues introduced by the actuator. Data analysis challenge is related to the presence of the kicks: they represent a high-noise contribution and need to be removed, thus leaving short gaps in data. This article presents preliminary data of the LPF free-fall measurement campaign and describes the three data analysis techniques developed to mitigate the presence of gaps.

Electrostatic demonstration of free-fall weightlessness

NASA Astrophysics Data System (ADS)

Balukovic, Jasmina; Slisko, Josip; Corona Cruz, Adrian

2015-05-01

The phenomena of free-fall weightlessness have been demonstrated to students for many years in a number of different ways. The essential basis of all these demonstrations is the fact that in free-falling, gravitationally accelerated systems, the weight force and weight-related forces (for example, friction and hydrostatic forces) disappear. In this article, an original electrostatic demonstration of weightlessness is presented. A charged balloon fixed at the opening of a plastic container cannot lift a light styrofoam sphere sitting on the bottom when the container is at rest. However, while the system is in free-fall, the sphere becomes weightless and the charged balloon is able to lift it electrostatically.

UHF wearable battery free sensor module for activity and falling detection.

PubMed

Nam Trung Dang; Thang Viet Tran; Wan-Young Chung

2016-08-01

Falling is one of the most serious medical and social problems in aging population. Therefore taking care of the elderly by detecting activity and falling for preventing and mitigating the injuries caused by falls needs to be concerned. This study proposes a wearable, wireless, battery free ultra-high frequency (UHF) smart sensor tag module for falling and activity detection. The proposed tag is powered by UHF RF wave from reader and read by a standard UHF Electronic Product Code (EPC) Class-1 Generation-2 reader. The battery free sensor module could improve the wearability of the wireless device. The combination of accelerometer signal and received signal strength indication (RSSI) from a reader in the passive smart sensor tag detect the activity and falling of the elderly very successfully. The fabricated smart sensor tag module has an operating range of up to 2.5m and conducting in real-time activity and falling detection.

Assessment of head injury risk associated with feet-first free falls in 12-month-old children using an anthropomorphic test device.

PubMed

Thompson, Angela K; Bertocci, Gina; Pierce, Mary Clyde

2009-04-01

Short distance falls are a common false history provided in cases of child abuse. Falls are also a common occurrence in ambulating young children. The purpose of this study was to determine the risk of head injury in short distance feet-first free falls for a 12-month-old child. Feet-first free falls were simulated using an anthropomorphic test device. Three fall heights and five surfaces were tested to determine whether changing fall environment characteristics leads to differences in head injury risk outcomes. Linear head accelerations were measured and angular head accelerations in the anterior-posterior direction were determined. Head injury criteria values and impact durations were also determined for each fall. The mean peak linear head acceleration across all trials was 52.2g. HIC15 values were all below the injury assessment reference value. The mean peak angular head acceleration across all trials was 4,246 rad/s2. Impact durations ranged from 12.1 milliseconds to 27.8 milliseconds. In general, head accelerations were greater and impact durations were lower for surfaces with lower coefficients of restitution (a measure of resiliency). In falls onto wood and linoleum over concrete, the ground-based fall was associated with greater accelerations than the two higher fall heights. Results show that fall dynamics play an important role in head injury outcome measures. Different fall heights and impact surfaces led to differences in head injury risk, but the risk of severe head injury across all tested scenarios was low for a 12-month-old child in feet-first free falls.

Evaluation of a Universally-Free School Breakfast Program Demonstration Project: Central Falls, Rhode Island.

ERIC Educational Resources Information Center

Cook, John T.; Ohri-Vachaspati, Punam; Kelly, Gayle Leitch

In early 1994, Central Falls, Rhode Island's Kids First, a collaborative partnership between the Central Falls School Department and local community leaders, launched a pilot universally-free school breakfast program (UF-SBP) called "Operation Breakfast." One of the goals of Operation Breakfast was to improve SBP participation; school…

Free Fall and the Equivalence Principle Revisited

ERIC Educational Resources Information Center

Pendrill, Ann-Marie

2017-01-01

Free fall is commonly discussed as an example of the equivalence principle, in the context of a homogeneous gravitational field, which is a reasonable approximation for small test masses falling moderate distances. Newton's law of gravity provides a generalisation to larger distances, and also brings in an inhomogeneity in the gravitational field.…

Going nuts: Measuring free-fall acceleration by analyzing the sound of falling metal pieces

NASA Astrophysics Data System (ADS)

Kuhn, Jochen; Vogt, Patrik; Theilmann, Florian

2016-03-01

Galilei presented the kinematics of a one-dimensional accelerated motion with ease and in terms of elegant geometry. Moreover, he believed, "Philosophy [i.e. physics] is written in this grand book—I mean the universe—which stands continually open to our gaze, but it cannot be understood unless one first learns to comprehend the language and interpret the characters in which it is written. It is written in the language of mathematics, and its characters are triangles, circles, and other geometrical figures, without which it is humanly impossible to understand a single word of it." In classroom practice, however, it can be difficult to reveal this mathematical heart of nature; free fall and other accelerated motions often get obscured by friction or other sources of errors. In this paper, we introduce a method of analyzing free-fall motion indirectly by evaluating the noise of freely falling metal pieces. The method connects a deeper understanding of the mathematical structure of accelerated motion with the possibility to derive a numerical value for the free-fall acceleration g.

Gauge dependence and self-force from Galilean to Einsteinian free fall, compact stars falling into black holes, Hawking radiation and the Pisa tower at the general relativity centennial

NASA Astrophysics Data System (ADS)

Spallicci, Alessandro D. A. M.; van Putten, Maurice H. P. M.

2016-08-01

Obviously, in Galilean physics, the universality of free fall implies an inertial frame, which in turns implies that the mass m of the falling body is omitted (because it is a test mass; put otherwise, the center of mass of the system coincides with the center of the main, and fixed, mass M; or else, we consider only a homogeneous gravitational field). Conversely, an additional (in the opposite or same direction) acceleration proportional to m/M would rise either for an observer at the center of mass of the system, or for an observer at a fixed distance from the center of mass of M. These elementary, but overlooked, considerations fully respect the equivalence principle (EP) and the (local) identity of an inertial or a gravitational pull for an observer in the Einstein cabin. They value as fore-runners of the self-force and gauge dependency in general relativity. Because of its importance in teaching and in the history of physics, coupled to the introductory role to Einstein’s EP, the approximate nature of Galilei’s law of free fall is explored herein. When stepping into general relativity, we report how the geodesic free fall into a black hole was the subject of an intense debate again centered on coordinate choice. Later, we describe how the infalling mass and the emitted gravitational radiation affect the free fall motion of a body. The general relativistic self-force might be dealt with to perfectly fit into a geodesic conception of motion. Then, embracing quantum mechanics, real black holes are not classical static objects any longer. Free fall has to handle the Hawking radiation, and leads us to new perspectives on the varying mass of the evaporating black hole and on the varying energy of the falling mass. Along the paper, we also estimate our findings for ordinary masses being dropped from a Galilean or Einsteinian Pisa-like tower with respect to the current state of the art drawn from precise measurements in ground and space laboratories, and to the constraints posed by quantum measurements. Appendix A describes how education physics and high impact factor journals discuss the free fall. Finally, case studies conducted on undergraduate students and teachers are reviewed.

Human survivability of extreme impacts in free-fall.

DOT National Transportation Integrated Search

1963-08-01

Human deceleration tolerances beyond the limits imposed by voluntary experimental methods were studied by means of intensive case histories of 137 individuals who have survived extremely abrupt impacts in accidental, suicidal, and homicidal free-fall...

Perceived orientation in free-fall dependson visual, postural, and architectural factors

NASA Technical Reports Server (NTRS)

Lackner, J. R.; Graybiel, A.

1983-01-01

In orbital flight and in the free-fall phase of parabolic flight, feelings of inversion of self and spacecraft, or aircraft, are often experienced. It is shown here that perceived orientation in free-fall is dependent on the position of one's body in relation to the aircraft, the architectural features of the aircraft, and one's visual appreciation of the relative configurations of his body and the aircraft. Compelling changes in the apparent orientation of one's body and of the aircraft can be reliably and systematically induced by manipulating this relationship. Moreover, while free-floating in the absence of visual, touch, and pressure stimulation, all sense of orientation to the surroundings may be lost with only an awareness of the relative configuration of the body preserved. The absences of falling sensations during weightlessness points to the importance of visual and cognitive factors in eliciting such sensations.

Learning about Gravity I. Free Fall: A Guide for Teachers and Curriculum Developers

ERIC Educational Resources Information Center

Kavanagh, Claudine; Sneider, Cary

2007-01-01

This article is the first of a two-part review of research on children's and adults understanding of gravity and on how best to teach gravity concepts to students and teachers. This first article concerns free fall--how and why objects fall when they are dropped. The review begins with a brief historical sketch of how these ideas were developed in…

Gravity Modeling for Variable Fidelity Environments

NASA Technical Reports Server (NTRS)

Madden, Michael M.

2006-01-01

Aerospace simulations can model worlds, such as the Earth, with differing levels of fidelity. The simulation may represent the world as a plane, a sphere, an ellipsoid, or a high-order closed surface. The world may or may not rotate. The user may select lower fidelity models based on computational limits, a need for simplified analysis, or comparison to other data. However, the user will also wish to retain a close semblance of behavior to the real world. The effects of gravity on objects are an important component of modeling real-world behavior. Engineers generally equate the term gravity with the observed free-fall acceleration. However, free-fall acceleration is not equal to all observers. To observers on the sur-face of a rotating world, free-fall acceleration is the sum of gravitational attraction and the centrifugal acceleration due to the world's rotation. On the other hand, free-fall acceleration equals gravitational attraction to an observer in inertial space. Surface-observed simulations (e.g. aircraft), which use non-rotating world models, may choose to model observed free fall acceleration as the gravity term; such a model actually combines gravitational at-traction with centrifugal acceleration due to the Earth s rotation. However, this modeling choice invites confusion as one evolves the simulation to higher fidelity world models or adds inertial observers. Care must be taken to model gravity in concert with the world model to avoid denigrating the fidelity of modeling observed free fall. The paper will go into greater depth on gravity modeling and the physical disparities and synergies that arise when coupling specific gravity models with world models.

THE FREE-FALL TIME OF FINITE SHEETS AND FILAMENTS

DOE Office of Scientific and Technical Information (OSTI.GOV)

Toala, Jesus A.; Vazquez-Semadeni, Enrique; Gomez, Gilberto C.

2012-01-10

Molecular clouds often exhibit filamentary or sheet-like shapes. We compute the free-fall time ({tau}{sub ff}) for finite, uniform, self-gravitating circular sheets and filamentary clouds of small but finite thickness, so that their volume density {rho} can still be defined. We find that, for thin sheets, the free-fall time is larger than that of a uniform sphere with the same volume density by a factor proportional to {radical}A, where the aspect ratio A is given by A = R/h, R being the sheet's radius and h is its thickness. For filamentary clouds, the aspect ratio is defined as A=L/R, where Lmore » is the filament's half-length and R is its (small) radius, and the modification factor is more complicated, although in the limit of large A it again reduces to nearly {radical}A. We propose that our result for filamentary shapes naturally explains the ubiquitous configuration of clumps fed by filaments observed in the densest structures of molecular clouds. Also, the longer free-fall times for non-spherical geometries in general may contribute toward partially alleviating the 'star formation conundrum', namely, the star formation rate in the Galaxy appears to be proceeding in a timescale much larger than the total molecular mass in the Galaxy divided by its typical free-fall time. If molecular clouds are in general formed by thin sheets and long filaments, then their relevant free-fall time may have been systematically underestimated, possibly by factors of up to one order of magnitude.« less

Survival of high-velocity free-falls in water.

DOT National Transportation Integrated Search

1965-04-01

Forty-four cases of free-falls survived by individuals impacting water environments under conditions of high velocity (50 to 116 ft/sec, corrected for aerodynamic drag) have been intensively investigated and analyzed. Ages varied from 7 to 80 years a...

Planning and executing motions for multibody systems in free-fall. Ph.D. Thesis

NASA Technical Reports Server (NTRS)

Cameron, Jonathan M.

1991-01-01

The purpose of this research is to develop an end-to-end system that can be applied to a multibody system in free-fall to analyze its possible motions, save those motions in a database, and design a controller that can execute those motions. A goal is for the process to be highly automated and involve little human intervention. Ideally, the output of the system would be data and algorithms that could be put in ROM to control the multibody system in free-fall. The research applies to more than just robots in space. It applies to any multibody system in free-fall. Mathematical techniques from nonlinear control theory were used to study the nature of the system dynamics and its possible motions. Optimization techniques were applied to plan motions. Image compression techniques were proposed to compress the precomputed motion data for storage. A linearized controller was derived to control the system while it executes preplanned trajectories.

Low-gravity processing of superconducting compounds

NASA Technical Reports Server (NTRS)

Otto, G. H.

1976-01-01

Low gravity conditions can be sustained on earth for several seconds in an evacuated drop tube. Because radiation cooling is most effective at high temperatures, the refractive metals and alloys are prime candidates for free fall solidification. The results of initial experiments on droplet formation, droplet release, critical size and evaporation losses are given. The time required for free fall solidification of different size droplets is calculated. The materials studied were copper, niobium and vanadium, and a niobium-tin alloys. Improvements in purity, composition, homogeneity and stoichiometry are expected during free fall solidification of niobium based alloys which should become evident in an increase in the superconducting transition temperature.

Solidification Dynamics of Spherical Drops in a Free Fall Environment

NASA Technical Reports Server (NTRS)

Grugel, Richard N.; Brush, Lucien N.

2006-01-01

Silver drops (99.9%, 4, 5, 7, and 9 mm diameter) were levitated, melted, and released to fall through Marshall Space Flight Center's 105 meter drop tube in helium - 6% hydrogen and pure argon atmospheres. By varying a drop s initial superheat the extent of solidification prior to impact ranged from complete to none during the approx. 4.6s of free fall time. Comparison of the experimental observations is made with numerical solutions to a model of the heat transfer and solidification kinetics associated with cooling of the drop during free fall, particularly with regard to the fraction of liquid transformed. Analysis reveals the relative importance ,of the initial parameters affecting the cooling and solidification rates within the drop. A discussion of the conditions under which the actual observations deviate from the assumptions used in the model is presented.

Solidification Dynamics of Metal Drops in a Free Fall Environment

NASA Technical Reports Server (NTRS)

Grugel, R. N.; Brush, L. N.; Curreri, Peter A. (Technical Monitor)

2001-01-01

Comparison of experimental observations were made with numerical solutions to a model of the heat transfer and solidification kinetics associated with the cooling of a molten drop during free fall, particularly with regard to the fraction of liquid transformed. Experimentally, silver drops (99.9%, 4-9 mm diameter) were levitated, melted, and released to fall through Marshall Space Flight Center's 105m drop tube in helium - 6% hydrogen and argon atmospheres. By systematically varying the drops initial superheat the extent of solidification prior to impact ranged from complete to none during the approximately 4.6s of free fall time. Analysis reveals the relative importance of the initial parameters affecting the cooling and solidification rates within the drop. A discussion of the conditions under which the actual observations deviate from the assumptions used in the model is presented.

46 CFR 199.153 - Survival craft launching and recovery arrangements using falls and a winch.

Code of Federal Regulations, 2013 CFR

2013-10-01

... falls and a winch. 199.153 Section 199.153 Shipping COAST GUARD, DEPARTMENT OF HOMELAND SECURITY... Requirements for All Vessels § 199.153 Survival craft launching and recovery arrangements using falls and a... appliances for free-fall launching arrangements, from a position within the survival craft. (b) Each fall...

46 CFR 199.153 - Survival craft launching and recovery arrangements using falls and a winch.

Code of Federal Regulations, 2014 CFR

2014-10-01

... falls and a winch. 199.153 Section 199.153 Shipping COAST GUARD, DEPARTMENT OF HOMELAND SECURITY... Requirements for All Vessels § 199.153 Survival craft launching and recovery arrangements using falls and a... appliances for free-fall launching arrangements, from a position within the survival craft. (b) Each fall...

46 CFR 199.153 - Survival craft launching and recovery arrangements using falls and a winch.

Code of Federal Regulations, 2012 CFR

2012-10-01

... falls and a winch. 199.153 Section 199.153 Shipping COAST GUARD, DEPARTMENT OF HOMELAND SECURITY... Requirements for All Vessels § 199.153 Survival craft launching and recovery arrangements using falls and a... appliances for free-fall launching arrangements, from a position within the survival craft. (b) Each fall...

Analysis of the free-fall behavior of liquid-metal drops in a gaseous atmosphere

NASA Technical Reports Server (NTRS)

Mccoy, J. Kevin; Markworth, Alan J.; Collings, E. W.; Brodkey, Robert S.

1987-01-01

The free-fall of a liquid-metal drop and heat transfer from the drop to its environment are described for both a gaseous atmosphere and vacuum. A simple model, in which the drop is assumed to fall rectilinearly with behavior like that of a rigid particle, is developed first, then possible causes of deviation from this behavior are discussed. The model is applied to describe solidification of drops in a drop tube. Possible future developments of the model are suggested.

Solidification Dynamics of Silver Drops in a Free Fall Environment

NASA Technical Reports Server (NTRS)

Grugel, Richard N.; Brush, Lucien N.

1999-01-01

Silver drops (99.9%, 4, 5, 7, and 9 mm diameter) were levitated, melted, and released to fall through Marshall Space Flight Center's 105m drop tube in helium - 6% hydrogen and pure argon atmospheres. By systematically varying the initial superheat condition of the drop the extent of solidification prior to impact ranged from complete to none during the approximately 4.6s of free fall time. Comparison of the experimental observations is made with numerical solutions to a model of the heat transfer and solidification kinetics associated with cooling of the drop during free fall, particularly with regard to the fraction of liquid transformed. Analysis reveals the relative importance of the initial parameters affecting the cooling and solidification rates within the drop. A discussion of the conditions under which the actual observations deviate from the assumptions used in the model is presented.

29 CFR Appendix B to Subpart I of... - General Testing Conditions and Additional Guidelines for Personal Fall Protection Systems (Non...

Code of Federal Regulations, 2014 CFR

2014-07-01

... Personal Fall Protection Systems (Non-Mandatory) B Appendix B to Subpart I of Part 1915 Labor Regulations... Guidelines for Personal Fall Protection Systems (Non-Mandatory) 1. Personal fall arrest systems—(a) General... create the free fall distance should be the one supplied with the system, or in its absence, the least...

29 CFR Appendix B to Subpart I of... - General Testing Conditions and Additional Guidelines for Personal Fall Protection Systems (Non...

Code of Federal Regulations, 2012 CFR

2012-07-01

... Personal Fall Protection Systems (Non-Mandatory) B Appendix B to Subpart I of Part 1915 Labor Regulations... Guidelines for Personal Fall Protection Systems (Non-Mandatory) 1. Personal fall arrest systems—(a) General... create the free fall distance should be the one supplied with the system, or in its absence, the least...

29 CFR Appendix B to Subpart I of... - General Testing Conditions and Additional Guidelines for Personal Fall Protection Systems (Non...

Code of Federal Regulations, 2013 CFR

2013-07-01

... Personal Fall Protection Systems (Non-Mandatory) B Appendix B to Subpart I of Part 1915 Labor Regulations... Guidelines for Personal Fall Protection Systems (Non-Mandatory) 1. Personal fall arrest systems—(a) General... create the free fall distance should be the one supplied with the system, or in its absence, the least...

Free Fall and Harmonic Oscillations: Analyzing Trampoline Jumps

ERIC Educational Resources Information Center

Pendrill, Ann-Marie; Eager, David

2015-01-01

Trampolines can be found in many gardens and also in some playgrounds. They offer an easily accessible vertical motion that includes free fall. In this work, the motion on a trampoline is modelled by assuming a linear relation between force and deflection, giving harmonic oscillations for small amplitudes. An expression for the cycle-time is…

A Teaching--Learning Sequence on Free Fall Motion

ERIC Educational Resources Information Center

Borghi, L.; De Ambrosis, A.; Lamberti, N.; Mascheretti, P.

2005-01-01

A teaching--learning sequence is presented that is designed to help high school pupils gain awareness about the independence of the vertical and horizontal components of free fall motion. The approach we propose is based on the use of experimental activities and computer simulations designed specifically to help pupils reflect on the experiments…

Free Falling in Stratified Fluids

NASA Astrophysics Data System (ADS)

Lam, Try; Vincent, Lionel; Kanso, Eva

2017-11-01

Leaves falling in air and discs falling in water are examples of unsteady descents due to complex interaction between gravitational and aerodynamic forces. Understanding these descent modes is relevant to many branches of engineering and science such as estimating the behavior of re-entry space vehicles to studying biomechanics of seed dispersion. For regularly shaped objects falling in homogenous fluids, the motion is relatively well understood. However, less is known about how density stratification of the fluid medium affects the falling behavior. Here, we experimentally investigate the descent of discs in both pure water and in stable linearly stratified fluids for Froude numbers Fr 1 and Reynolds numbers Re between 1000 -2000. We found that stable stratification (1) enhances the radial dispersion of the disc at landing, (2) increases the descent time, (3) decreases the inclination (or nutation) angle, and (4) decreases the fluttering amplitude while falling. We conclude by commenting on how the corresponding information can be used as a predictive model for objects free falling in stratified fluids.

Electrostatic Positioning System for a free fall test at drop tower Bremen and an overview of tests for the Weak Equivalence Principle in past, present and future

NASA Astrophysics Data System (ADS)

Sondag, Andrea; Dittus, Hansjörg

2016-08-01

The Weak Equivalence Principle (WEP) is at the basis of General Relativity - the best theory for gravitation today. It has been and still is tested with different methods and accuracies. In this paper an overview of tests of the Weak Equivalence Principle done in the past, developed in the present and planned for the future is given. The best result up to now is derived from the data of torsion balance experiments by Schlamminger et al. (2008). An intuitive test of the WEP consists of the comparison of the accelerations of two free falling test masses of different composition. This has been carried through by Kuroda & Mio (1989, 1990) with the up to date most precise result for this setup. There is still more potential in this method, especially with a longer free fall time and sensors with a higher resolution. Providing a free fall time of 4.74 s (9.3 s using the catapult) the drop tower of the Center of Applied Space Technology and Microgravity (ZARM) at the University of Bremen is a perfect facility for further improvements. In 2001 a free fall experiment with high sensitive SQUID (Superconductive QUantum Interference Device) sensors tested the WEP with an accuracy of 10-7 (Nietzsche, 2001). For optimal conditions one could reach an accuracy of 10-13 with this setup (Vodel et al., 2001). A description of this experiment and its results is given in the next part of this paper. For the free fall of macroscopic test masses it is important to start with precisely defined starting conditions concerning the positions and velocities of the test masses. An Electrostatic Positioning System (EPS) has been developed to this purpose. It is described in the last part of this paper.

A torsion pendulum test of the Lisa Pathfinder free-fall mode

NASA Astrophysics Data System (ADS)

Russano, Giuliana; Dolesi, Rita; Cavalleri, Antonella; Hueller, Mauro; Vitale, Stefano; Weber, William Joseph; Tu, HaiBo

The LISA Pathfinder geodesic explorer mission for gravitational wave astronomy aims to demonstrate the proof of a low acceleration noise level. The relative acceleration between two test masses free falling in orbit is perturbed by the presence of a larger constant relative acceleration that must be actively compensated in order to keep the test particles centered inside an orbiting apparatus. The actuation force applied to compensate this effect introduces a dominant source of force noise. To suppress this noise source, a “free-fall” actuation control scheme has been designed: actuation is limited to brief impulses, with test masses in free fall in between two “kicks”, with this actuation-free motion then analyzed for the remaining sources of acceleration ultra noise. In this work, we will discuss and present preliminary data for an on-ground torsion pendulum experiment to test this technique, and the associated analysis algorithms, at a level nearing the sub-femto-g/sqrt(Hz) performance required for LISA Pathfinder.

How Can "Weightless" Astronauts Be Weighed?

ERIC Educational Resources Information Center

Carnicer, Jesus; Reyes, Francisco; Guisasola, Jenaro

2012-01-01

In introductory physics courses, within the context of studying Newton's laws, it is common to consider the problem of a body's "weight" when it is in free fall. The solution shows that the "weight" is zero and this leads to a discussion of the concept of weight. There are permanent free-fall situations such as astronauts in a spacecraft orbiting…

When Does Air Resistance Become Significant in Projectile Motion?

ERIC Educational Resources Information Center

Mohazzabi, Pirooz

2018-01-01

In an article in this journal, it was shown that air resistance could never be a significant source of error in typical free-fall experiments in introductory physics laboratories. Since projectile motion is the two-dimensional version of the free-fall experiment and usually follows the former experiment in such laboratories, it seemed natural to…

Equivalence principles and electromagnetism

NASA Technical Reports Server (NTRS)

Ni, W.-T.

1977-01-01

The implications of the weak equivalence principles are investigated in detail for electromagnetic systems in a general framework. In particular, it is shown that the universality of free-fall trajectories (Galileo weak equivalence principle) does not imply the validity of the Einstein equivalence principle. However, the Galileo principle plus the universality of free-fall rotation states does imply the Einstein principle.

Experimental Evaluation of the Drag Coefficient of Water Rockets by a Simple Free-Fall Test

ERIC Educational Resources Information Center

Barrio-Perotti, R.; Blanco-Marigorta, E. Arguelles-Diaz, K.; Fernandez-Oro, J.

2009-01-01

The flight trajectory of a water rocket can be reasonably calculated if the magnitude of the drag coefficient is known. The experimental determination of this coefficient with enough precision is usually quite difficult, but in this paper we propose a simple free-fall experiment for undergraduate students to reasonably estimate the drag…

High free fall with survival.

PubMed

Layton, T R; Villella, E R; Kelly, E G

1981-11-01

A free fall, the unimpeded drop of a body from a known point to a known impaction point, is common in modern society. Death usually results when distance is more than six stories. The following case report describes the circumstances which allowed a young man attempting suicide to survive a 17-storey free fall. Although his impact velocity was estimated to be 72 m.p.h. (uncorrected for air drag), he impacted in a supine position on an automobile trunk lid so that some of the force was dissipated by tires and shock absorbers. Multiple fractures and soft-tissue injuries and a subsequent stress ulcer were successfully treated and the patient has a satisfactory level of physical activity while remaining under psychiatric care 1 year postinjury.

Internal models and prediction of visual gravitational motion.

PubMed

Zago, Myrka; McIntyre, Joseph; Senot, Patrice; Lacquaniti, Francesco

2008-06-01

Baurès et al. [Baurès, R., Benguigui, N., Amorim, M.-A., & Siegler, I. A. (2007). Intercepting free falling objects: Better use Occam's razor than internalize Newton's law. Vision Research, 47, 2982-2991] rejected the hypothesis that free-falling objects are intercepted using a predictive model of gravity. They argued instead for "a continuous guide for action timing" based on visual information updated till target capture. Here we show that their arguments are flawed, because they fail to consider the impact of sensori-motor delays on interception behaviour and the need for neural compensation of such delays. When intercepting a free-falling object, the delays can be overcome by a predictive model of the effects of gravity on target motion.

The Pendulum: From Constrained Fall to the Concept of Potential

ERIC Educational Resources Information Center

Bevilacqua, Fabio; Falomo, Lidia; Fregonese, Lucio; Giannetto, Enrico; Giudice, Franco; Mascheretti, Paolo

2006-01-01

Kuhn underlined the relevance of Galileo's gestalt switch in the interpretation of a swinging body from constrained fall to time metre. But the new interpretation did not eliminate the older one. The constrained fall, both in the motion of pendulums and along inclined planes, led Galileo to the law of free fall. Experimenting with physical…

Highlights of the high-temperature falling particle receiver project: 2012 - 2016

NASA Astrophysics Data System (ADS)

Ho, C. K.; Christian, J.; Yellowhair, J.; Jeter, S.; Golob, M.; Nguyen, C.; Repole, K.; Abdel-Khalik, S.; Siegel, N.; Al-Ansary, H.; El-Leathy, A.; Gobereit, B.

2017-06-01

A 1 MWt continuously recirculating falling particle receiver has been demonstrated at Sandia National Laboratories. Free-fall and obstructed-flow receiver designs were tested with particle mass flow rates of ˜1 - 7 kg/s and average irradiances up to 1,000 suns. Average particle outlet temperatures exceeded 700 °C for the free-fall tests and reached nearly 800 °C for the obstructed-flow tests, with peak particle temperatures exceeding 900 °C. High particle heating rates of ˜50 to 200 °C per meter of illuminated drop length were achieved for the free-fall tests with mass flow rates ranging from 1 - 7 kg/s and for average irradiances up to ˜ 700 kW/m2. Higher temperatures were achieved at the lower particle mass flow rates due to less shading. The obstructed-flow design yielded particle heating rates over 300 °C per meter of illuminated drop length for mass flow rates of 1 - 3 kg/s for irradiances up to ˜1,000 kW/m2. The thermal efficiency was determined to be ˜60 - 70% for the free-falling particle tests and up to ˜80% for the obstructed-flow tests. Challenges encountered during the tests include particle attrition and particle loss through the aperture, reduced particle mass flow rates at high temperatures due to slot aperture narrowing and increased friction, and deterioration of the obstructed-flow structures due to wear and oxidation. Computational models were validated using the test data and will be used in future studies to design receiver configurations that can increase the thermal efficiency.

Experiments Using Cell Phones in Physics Classroom Education: The Computer-Aided "g" Determination

ERIC Educational Resources Information Center

Vogt, Patrik; Kuhn, Jochen; Muller, Sebastian

2011-01-01

This paper continues the collection of experiments that describe the use of cell phones as experimental tools in physics classroom education. We describe a computer-aided determination of the free-fall acceleration "g" using the acoustical Doppler effect. The Doppler shift is a function of the speed of the source. Since a free-falling objects…

Using Tracker to Understand "Toss Up" and Free Fall Motion: A Case Study

ERIC Educational Resources Information Center

Wee, Loo Kang; Tan, Kim Kia; Leong, Tze Kwang; Tan, Ching

2015-01-01

This paper reports the use of Tracker as a computer-based learning tool to support effective learning and teaching of "toss up" and free fall motion for beginning secondary three (15?year-old) students. The case study involved (N = 123) students from express pure physics classes at a mainstream school in Singapore. We used eight…

Free Fall Misconceptions: Results of a Graph Based Pre-Test of Sophomore Civil Engineering Students

ERIC Educational Resources Information Center

Montecinos, Alicia M.

2014-01-01

A partially unusual behaviour was found among 14 sophomore students of civil engineering who took a pre test for a free fall laboratory session, in the context of a general mechanics course. An analysis contemplating mathematics models and physics models consistency was made. In all cases, the students presented evidence favoring a correct free…

[The righting reaction in the free fall of rats after a flight on the Kosmos-936 biosatellite].

PubMed

Aĭzikov, G S; Markin, A S; Shipov, A A

1992-01-01

The free fall turning over reaction has been studied in the weightless and centrifuged rats flown on board Cosmos 936. There occur particular changes of the reaction in the weightless rats after landing and its complete absence in eyes-closed centrifuged rats. The possible mechanisms responsible for the observed alterations are discussed.

Identifying Balance Measures Most Likely to Identify Recent Falls.

PubMed

Criter, Robin E; Honaker, Julie A

2016-01-01

Falls sustained by older adults are an increasing health care issue. Early identification of those at risk for falling can lead to successful prevention of falls. Balance complaints are common among individuals who fall or are at risk for falling. The purpose of this study was to evaluate the clinical utility of a multifaceted balance protocol used for fall risk screening, with the hypothesis that this protocol would successfully identify individuals who had a recent fall (within the previous 12 months). This is a retrospective review of 30 individuals who self-referred for a free fall risk screening. Measures included case history, Activities-Specific Balance Confidence Scale, modified Clinical Test of Sensory Interaction on Balance, Timed Up and Go test, and Dynamic Visual Acuity. Statistical analyses were focused on the ability of the test protocol to identify a fall within the past 12 months and included descriptive statistics, clinical utility indices, logistic regression, receiver operating characteristic curve, area under the curve analysis, effect size (Cohen d), and Spearman correlation coefficients. All individuals who self-referred for this free screening had current imbalance complaints, and were typically women (70%), had a mean age of 77.2 years, and had a fear of falling (70%). Almost half (46.7%) reported at least 1 lifetime fall and 40.0% within the past 12 months. Regression analysis suggested that the Timed Up and Go test was the most important indicator of a recent fall. A cutoff score of 12 or more seconds was optimal (sensitivity: 83.3%; specificity: 61.1%). Older adults with current complaints of imbalance have a higher rate of falls, fall-related injury, and fear of falling than the general community-dwelling public. The Timed Up and Go test is useful for determining recent fall history in individuals with imbalance.

Gravity brake

DOEpatents

Lujan, Richard E.

2001-01-01

A mechanical gravity brake that prevents hoisted loads within a shaft from free-falling when a loss of hoisting force occurs. A loss of hoist lifting force may occur in a number of situations, for example if a hoist cable were to break, the brakes were to fail on a winch, or the hoist mechanism itself were to fail. Under normal hoisting conditions, the gravity brake of the invention is subject to an upward lifting force from the hoist and a downward pulling force from a suspended load. If the lifting force should suddenly cease, the loss of differential forces on the gravity brake in free-fall is translated to extend a set of brakes against the walls of the shaft to stop the free fall descent of the gravity brake and attached load.

Bose-Einstein condensation in microgravity.

PubMed

van Zoest, T; Gaaloul, N; Singh, Y; Ahlers, H; Herr, W; Seidel, S T; Ertmer, W; Rasel, E; Eckart, M; Kajari, E; Arnold, S; Nandi, G; Schleich, W P; Walser, R; Vogel, A; Sengstock, K; Bongs, K; Lewoczko-Adamczyk, W; Schiemangk, M; Schuldt, T; Peters, A; Könemann, T; Müntinga, H; Lämmerzahl, C; Dittus, H; Steinmetz, T; Hänsch, T W; Reichel, J

2010-06-18

Albert Einstein's insight that it is impossible to distinguish a local experiment in a "freely falling elevator" from one in free space led to the development of the theory of general relativity. The wave nature of matter manifests itself in a striking way in Bose-Einstein condensates, where millions of atoms lose their identity and can be described by a single macroscopic wave function. We combine these two topics and report the preparation and observation of a Bose-Einstein condensate during free fall in a 146-meter-tall evacuated drop tower. During the expansion over 1 second, the atoms form a giant coherent matter wave that is delocalized on a millimeter scale, which represents a promising source for matter-wave interferometry to test the universality of free fall with quantum matter.

Calculation of Water Entry Problem for Free-falling Bodies Using a Developed Cartesian Cut Cell Mesh

NASA Astrophysics Data System (ADS)

Wenhua, Wang; Yanying, Wang

2010-05-01

This paper describes the development of free surface capturing method on Cartesian cut cell mesh to water entry problem for free-falling bodies with body-fluid interaction. The incompressible Euler equations for a variable density fluid system are presented as governing equations and the free surface is treated as a contact discontinuity by using free surface capturing method. In order to be convenient for dealing with the problem with moving body boundary, the Cartesian cut cell technique is adopted for generating the boundary-fitted mesh around body edge by cutting solid regions out of a background Cartesian mesh. Based on this mesh system, governing equations are discretized by finite volume method, and at each cell edge inviscid flux is evaluated by means of Roe's approximate Riemann solver. Furthermore, for unsteady calculation in time domain, a time accurate solution is achieved by a dual time-stepping technique with artificial compressibility method. For the body-fluid interaction, the projection method of momentum equations and exact Riemann solution are applied in the calculation of fluid pressure on the solid boundary. Finally, the method is validated by test case of water entry for free-falling bodies.

10 CFR 32.101 - Schedule B-prototype tests for luminous safety devices for use in aircraft.

Code of Federal Regulations, 2012 CFR

2012-01-01

... 10 Energy 1 2012-01-01 2012-01-01 false Schedule B-prototype tests for luminous safety devices for... thermometer. (d) Shock test. The device shall be dropped upon a concrete or iron surface in a 3-foot free gravitational fall, or shall be subjected to equivalent treatment in a test device simulating such a free fall...

Measuring fN force variations in the presence of constant nN forces: a torsion pendulum ground test of the LISA Pathfinder free-fall mode

NASA Astrophysics Data System (ADS)

Russano, G.; Cavalleri, A.; Cesarini, A.; Dolesi, R.; Ferroni, V.; Gibert, F.; Giusteri, R.; Hueller, M.; Liu, L.; Pivato, P.; Tu, H. B.; Vetrugno, D.; Vitale, S.; Weber, W. J.

2018-02-01

LISA Pathfinder is a differential accelerometer with the main goal being to demonstrate the near perfect free-fall of reference test masses, as is needed for an orbiting gravitational wave observatory, with a target sensitivity of 30 fm s‑2 Hz-1/2 at 1 mHz. Any lasting background differential acceleration between the two test masses must be actively compensated, and noise associated with the applied actuation force can be a dominant source of noise. To remove this actuation, and the associated force noise, a ‘free-fall’ actuation control scheme has been designed; actuation is limited to brief impulses, with both test masses in free-fall in the time between the impulses, allowing measurement of the remaining acceleration noise sources. In this work, we present an on-ground torsion pendulum testing campaign of this technique and associated data analysis algorithms at a level nearing the sub-femto-g/\\sqrtHz performance required for LISA Pathfinder.

An alternative model of free fall

NASA Astrophysics Data System (ADS)

Lattery, Mark

2018-03-01

In Two World Systems (Galileo 1632/1661 Dialogues Concerning Two New Sciences (New York: Prometheus)), Galileo attempted to unify terrestrial and celestial motions using the Aristotelian principle of circularity. The result was a model of free fall that correctly predicts the linear increase of the velocity of an object released from rest near the surface of the Earth. This historical episode provides an opportunity to communicate the nature of science to students.

WOLF REXUS EXPERIMENT - European Planetary Science Congress

NASA Astrophysics Data System (ADS)

Buzdugan, A.

2017-09-01

WOLF experiment is developing a reaction wheel-based control system, effectively functioning as active nutation damper. One reaction wheel is used to reduce the undesirable lateral rates of spinning cylindrically symmetric free falling units, ejected from a sounding rocket. Once validated in REXUS flight, the concept and the design developed during WOLF experiment can be used for other application which require a flat spin of the free falling units.

Retrieval-travel-time model for free-fall-flow-rack automated storage and retrieval system

NASA Astrophysics Data System (ADS)

Metahri, Dhiyaeddine; Hachemi, Khalid

2018-03-01

Automated storage and retrieval systems (AS/RSs) are material handling systems that are frequently used in manufacturing and distribution centers. The modelling of the retrieval-travel time of an AS/RS (expected product delivery time) is practically important, because it allows us to evaluate and improve the system throughput. The free-fall-flow-rack AS/RS has emerged as a new technology for drug distribution. This system is a new variation of flow-rack AS/RS that uses an operator or a single machine for storage operations, and uses a combination between the free-fall movement and a transport conveyor for retrieval operations. The main contribution of this paper is to develop an analytical model of the expected retrieval-travel time for the free-fall flow-rack under a dedicated storage assignment policy. The proposed model, which is based on a continuous approach, is compared for accuracy, via simulation, with discrete model. The obtained results show that the maximum deviation between the continuous model and the simulation is less than 5%, which shows the accuracy of our model to estimate the retrieval time. The analytical model is useful to optimise the dimensions of the rack, assess the system throughput, and evaluate different storage policies.

29 CFR 1926.500 - Scope, application, and definitions applicable to this subpart.

Code of Federal Regulations, 2014 CFR

2014-07-01

... CC of this part. (iii) Fall protection requirements for employees performing steel erection work... for training in the installation and use of fall protection systems, except in relation to steel... component parts. Load refusal is the point where the ultimate strength is exceeded. Free fall means the act...

Modeling visual-based pitch, lift and speed control strategies in hoverflies

PubMed Central

Vercher, Jean-Louis

2018-01-01

To avoid crashing onto the floor, a free falling fly needs to trigger its wingbeats quickly and control the orientation of its thrust accurately and swiftly to stabilize its pitch and hence its speed. Behavioural data have suggested that the vertical optic flow produced by the fall and crossing the visual field plays a key role in this anti-crash response. Free fall behavior analyses have also suggested that flying insect may not rely on graviception to stabilize their flight. Based on these two assumptions, we have developed a model which accounts for hoverflies´ position and pitch orientation recorded in 3D with a fast stereo camera during experimental free falls. Our dynamic model shows that optic flow-based control combined with closed-loop control of the pitch suffice to stabilize the flight properly. In addition, our model sheds a new light on the visual-based feedback control of fly´s pitch, lift and thrust. Since graviceptive cues are possibly not used by flying insects, the use of a vertical reference to control the pitch is discussed, based on the results obtained on a complete dynamic model of a virtual fly falling in a textured corridor. This model would provide a useful tool for understanding more clearly how insects may or not estimate their absolute attitude. PMID:29361632

Equivalence principle for quantum systems: dephasing and phase shift of free-falling particles

NASA Astrophysics Data System (ADS)

Anastopoulos, C.; Hu, B. L.

2018-02-01

We ask the question of how the (weak) equivalence principle established in classical gravitational physics should be reformulated and interpreted for massive quantum objects that may also have internal degrees of freedom (dof). This inquiry is necessary because even elementary concepts like a classical trajectory are not well defined in quantum physics—trajectories originating from quantum histories become viable entities only under stringent decoherence conditions. From this investigation we posit two logically and operationally distinct statements of the equivalence principle for quantum systems. Version A: the probability distribution of position for a free-falling particle is the same as the probability distribution of a free particle, modulo a mass-independent shift of its mean. Version B: any two particles with the same velocity wave-function behave identically in free fall, irrespective of their masses. Both statements apply to all quantum states, including those without a classical correspondence, and also for composite particles with quantum internal dof. We also investigate the consequences of the interaction between internal and external dof induced by free fall. For a class of initial states, we find dephasing occurs for the translational dof, namely, the suppression of the off-diagonal terms of the density matrix, in the position basis. We also find a gravitational phase shift in the reduced density matrix of the internal dof that does not depend on the particle’s mass. For classical states, the phase shift has a natural classical interpretation in terms of gravitational red-shift and special relativistic time-dilation.

Selecting Power-Efficient Signal Features for a Low-Power Fall Detector.

PubMed

Wang, Changhong; Redmond, Stephen J; Lu, Wei; Stevens, Michael C; Lord, Stephen R; Lovell, Nigel H

2017-11-01

Falls are a serious threat to the health of older people. A wearable fall detector can automatically detect the occurrence of a fall and alert a caregiver or an emergency response service so they may deliver immediate assistance, improving the chances of recovering from fall-related injuries. One constraint of such a wearable technology is its limited battery life. Thus, minimization of power consumption is an important design concern, all the while maintaining satisfactory accuracy of the fall detection algorithms implemented on the wearable device. This paper proposes an approach for selecting power-efficient signal features such that the minimum desirable fall detection accuracy is assured. Using data collected in simulated falls, simulated activities of daily living, and real free-living trials, all using young volunteers, the proposed approach selects four features from a set of ten commonly used features, providing a power saving of 75.3%, while limiting the error rate of a binary classification decision tree fall detection algorithm to 7.1%.Falls are a serious threat to the health of older people. A wearable fall detector can automatically detect the occurrence of a fall and alert a caregiver or an emergency response service so they may deliver immediate assistance, improving the chances of recovering from fall-related injuries. One constraint of such a wearable technology is its limited battery life. Thus, minimization of power consumption is an important design concern, all the while maintaining satisfactory accuracy of the fall detection algorithms implemented on the wearable device. This paper proposes an approach for selecting power-efficient signal features such that the minimum desirable fall detection accuracy is assured. Using data collected in simulated falls, simulated activities of daily living, and real free-living trials, all using young volunteers, the proposed approach selects four features from a set of ten commonly used features, providing a power saving of 75.3%, while limiting the error rate of a binary classification decision tree fall detection algorithm to 7.1%.

REDUCTION OF THE MOMENTUM OF FALLING BODIES

DOEpatents

Kendall, J.W.; Morrison, I.H.

1954-09-21

A means for catching free falling bodies that may be damaged upon impact is given. Several layers of floating gas-filled rubber balls are contained within a partially compartmented tank of liquid. The compartment extends from beneath the surface of the liquid to that height necessary to contain the desired number of layers of the balls. The balls and the liquid itself break the force of the fall by absorbing the kinetic energy of falling body. The body may then be retrieved from the floor of the tank by a rake that extends from outside of the tank through the free surface area and underneath the compartment wall. This arrangement is particularly useful in collecting irradiated atomic fuel rods that are discharged from a reactor at considerable height without damaging the thin aluminum jacket of the rods.

Super free fall for a container composed of diverging flat plates

NASA Astrophysics Data System (ADS)

Medina, A.; Torres, A.; Peralta, S.; Weidman, P. D.

2010-11-01

We have analyzed experimentally and theoretically the characteristics of the upper free surface of a liquid column released from rest in a vertical container whose cross-section opens slowly in the downward direction. In distinction with the work of Villermaux and Pomeau (2010) for a conical container, we consider a container composed of slightly inclined flat surfaces. At small times for which viscous effects can be neglected, the free surface moves downward with an acceleration larger than gravity. The existence of a nipple centered on the upper free surface with amplitude an increasing function of time is observed. A one-dimensional model of the initial acceleration for flat, slightly expanding walls reproduces the observed super free fall experiments fairly well. Details of the nipple development will be presented.

Microgravity simulations with human lymphocytes in the free fall machine and in the random positioning machine

NASA Technical Reports Server (NTRS)

Schwarzenberg, M.; Pippia, P.; Meloni, M. A.; Cossu, G.; Cogoli-Greuter, M.; Cogoli, A.

1998-01-01

The purpose of this paper is to present the results obtained in our laboratory with both instruments, the FFM [free fall machine] and the RPM [random positioning machine], to compare them with the data from earlier experiments with human lymphocytes conducted in the FRC [fast rotating clinostat] and in space. Furthermore, the suitability of the FFM and RPM for research in gravitational cell biology is discussed.

Variations in gravitoinertial force level affect the gain of the vestibulo-ocular reflex - Implications of the etiology of space motion sickness

NASA Technical Reports Server (NTRS)

Lackner, J. R.; Graybiel, A.

1981-01-01

Recordings of horizontal nystagmus were obtained on 16 male subjects exposed to repeated patterns of horizontal angular acceleration, constant velocity rotation, and sudden-stop deceleration in the laboratory and in the free-fall and high-force periods of parabolic flight. Nystagmus intensity was a clear function of gravitoinertial force level: slow phase velocity and beat frequency increased during exposure to high force levels and decreased in free-fall compared to values obtained at 1 G. These findings indicate that the gain of the vestibulo-ocular reflex decreases in free-fall. This fact likely accounts for the disorientation and dizziness sometimes experienced by astronauts when moving their heads in the early phases of orbital flight and again after splashdown. The implications of the present findings, both for the etiology and for the treatment of space motion sickness, are discussed.

Femur loading in feet-first fall experiments using an anthropomorphic test device.

PubMed

Thompson, Angela; Bertocci, Gina; Smalley, Craig

2018-03-31

Femur fractures are a common orthopedic injury in young children. Falls account for a large portion of accidental femur fractures in young children, but there is also a high prevalence of femur fractures in child abuse, with falls often provided as false histories. Objective information regarding fracture potential in short distance fall scenarios may aid in assessing whether a child's injuries are the result of abuse or an accidental fall. Knowledge of femur loading is the first step towards understanding likelihood of fracture in a fall. Characterize femur loading during feet-first free falls using a surrogate representing a 12-month-old child. The femur and hip joint of a surrogate representing a 12-month-old were modified to improve biofidelity and measure femur loading; 6-axis load cells were integrated into the proximal and distal femur. Femur modification was based upon CT imaging of cadaveric femurs in children 10-14 months of age. Using the modified 12-month-old surrogate, feet-first free falls from 69 cm and 119 cm heights onto padded carpet and linoleum were conducted to assess fall dynamics and determine femur loading. Femur compression, bending moment, shear and torsional moment were measured for each fall. Fall dynamics differed across fall heights, but did not substantially differ by impact surface type. Significant differences were found in all loading conditions across fall heights, while only compression and bending loads differed between carpet and linoleum surfaces. Maximum compression, bending, torsion and shear occurred in 119 cm falls and were 572 N, 23 N-m, 11 N-m and 281 N, respectively. Fall dynamics play an important role in the biomechanical assessment of falls. Fall height was found to influence both fall dynamics and femur loading, while impact surface affected only compression and bending in feet-first falls; fall dynamics did not differ across carpet and linoleum. Improved pediatric thresholds are necessary to predict likelihood of fracture, but morphologically accurate representation of the lower extremity, along with accurate characterization of loading in falls are a crucial first step. Copyright © 2018 Elsevier Ltd and Faculty of Forensic and Legal Medicine. All rights reserved.

Bridging the Conceptual Gap between Free Fall and Drag-Dominated Regimes

ERIC Educational Resources Information Center

de Obaldia, Elida; Miller, Norma; Wittel, Fred; Jaimison, George; Wallis, Kendra

2016-01-01

Some misconceptions about physics are hard to change. For example, students continue to believe that heavier objects fall faster than light ones, even after a year of physics instruction. Physics misconceptions are persistent. Light objects do fall more slowly if their size-to-weight ratio is sufficient for drag to be appreciable. Motion through a…

Learning about Gravity I. Free Fall: A Guide for Teachers and Curriculum Developers

NASA Astrophysics Data System (ADS)

Kavanagh, Claudine; Sneider, Cary

This article is the first of a two-part review of research on children's and adults understanding of gravity and on how best to teach gravity concepts to students and teachers. This first article concerns free fall—how and why objects fall when they are dropped. The review begins with a brief historical sketch of how these ideas were developed in human history, followed by a summary of the relevant standards and benchmarks. The body of research is organized by the nature of the findings, beginning with studies of the youngest children, followed by older students, adults, and teachers. Although a diversity of misconceptions are found at all age levels, in general children, between the ages of 7 and 9 progress from the idea that things fall because they're not supported to things fall because they're "heavy." Between the ages of 9 and 13, students begin to use the term "gravity," an unseen force, to explain falling, such as "gravity acts just on heavy objects," or "things fall because air is pushing them down." Surprisingly, many high school and college students who can successfully solve numerical problems involving gravity hold qualitative misconceptions similar to those held by much younger students. The finding that even college physics students have significant misconceptions about free fall underscores the importance of effective teaching at the middle and high school levels. Some studies have found that few teachers are aware of their students' misconceptions or know what to do about them. A few studies have reported success in helping students shed their misconceptions, leading to promising recommendations for curriculum development and teaching.

Primary acoustic signal structure during free falling drop collision with a water surface

DOE Office of Scientific and Technical Information (OSTI.GOV)

Chashechkin, Yu. D., E-mail: chakin@ipmnet.ru; Prokhorov, V. E., E-mail: prohorov@ipmnet.ru

2016-04-15

Consistent optical and acoustic techniques have been used to study the structure of hydrodynamic disturbances and acoustic signals generated as a free falling drop penetrates water. The relationship between the structures of hydrodynamic and acoustic perturbations arising as a result of a falling drop contacting with the water surface and subsequent immersion into water is traced. The primary acoustic signal is characterized, in addition to stably reproduced features (steep leading edge followed by long decay with local pressure maxima), by irregular high-frequency packets, which are studied for the first time. Reproducible experimental data are used to recognize constant and variablemore » components of the primary acoustic signal.« less

The effect of solidification rate on the formability of nickel aluminide containing iron and boron

NASA Technical Reports Server (NTRS)

Carro, G.; Flanagan, W. F.

1987-01-01

Following reports that rapid solidification improves the ductility of some nickel aluminides, an investigation has been conducted of the possibility of additional improvement in a nickel aluminide containing both Fe and B. Free fall-solidified and free fall/splat-quenched samples similar to those producible under microgravity conditions in space were prepared, and their microstructure was characterized. Attention is given to the preliminary results of tests quantitatively measuring mechanical properties.

Model-based and Model-free Machine Learning Techniques for Diagnostic Prediction and Classification of Clinical Outcomes in Parkinson's Disease.

PubMed

Gao, Chao; Sun, Hanbo; Wang, Tuo; Tang, Ming; Bohnen, Nicolaas I; Müller, Martijn L T M; Herman, Talia; Giladi, Nir; Kalinin, Alexandr; Spino, Cathie; Dauer, William; Hausdorff, Jeffrey M; Dinov, Ivo D

2018-05-08

In this study, we apply a multidisciplinary approach to investigate falls in PD patients using clinical, demographic and neuroimaging data from two independent initiatives (University of Michigan and Tel Aviv Sourasky Medical Center). Using machine learning techniques, we construct predictive models to discriminate fallers and non-fallers. Through controlled feature selection, we identified the most salient predictors of patient falls including gait speed, Hoehn and Yahr stage, postural instability and gait difficulty-related measurements. The model-based and model-free analytical methods we employed included logistic regression, random forests, support vector machines, and XGboost. The reliability of the forecasts was assessed by internal statistical (5-fold) cross validation as well as by external out-of-bag validation. Four specific challenges were addressed in the study: Challenge 1, develop a protocol for harmonizing and aggregating complex, multisource, and multi-site Parkinson's disease data; Challenge 2, identify salient predictive features associated with specific clinical traits, e.g., patient falls; Challenge 3, forecast patient falls and evaluate the classification performance; and Challenge 4, predict tremor dominance (TD) vs. posture instability and gait difficulty (PIGD). Our findings suggest that, compared to other approaches, model-free machine learning based techniques provide a more reliable clinical outcome forecasting of falls in Parkinson's patients, for example, with a classification accuracy of about 70-80%.

A Piece of Paper Falling Faster than Free Fall

ERIC Educational Resources Information Center

Vera, F.; Rivera, R.

2011-01-01

We report a simple experiment that clearly demonstrates a common error in the explanation of the classic experiment where a small piece of paper is put over a book and the system is let fall. This classic demonstration is used in introductory physics courses to show that after eliminating the friction force with the air, the piece of paper falls…

Including fall prevention for older adults in your trauma injury prevention program--introducing Farewell to Falls.

PubMed

Corman, Ellen

2009-01-01

With data showing that more than 50% of visits to our trauma center for older adults 65 years and older are due to falls, injury prevention programs in trauma centers should be paying more attention to the area of fall prevention for older adults. Farewell to Falls, a free, home-based program of Stanford Hospital and Clinic's trauma service, utilizes a multifaceted approach to help reduce falls. In addition to improving the lives of seniors, the program fulfills a community benefit goal and provides strong hospital marketing opportunities. This program is a benefit to hospitals and the older adults they serve.

Test of the Equivalence Principle in an Einstein Elevator

NASA Technical Reports Server (NTRS)

Shapiro, Irwin I.; Glashow, S.; Lorenzini, E. C.; Cosmo, M. L.; Cheimets, P.; Finkelstein, N.; Schneps, M.

2004-01-01

The scientific goal of the experiment is to test the equality of gravitational and inertial mass (i.e., to test the Principle of Equivalence) by measuring the independence of the rate of fall of bodies from the composition of the falling body. The measurement is accomplished by measuring the relative displacement (or equivalently acceleration) of two falling bodies of different materials which are the proof masses of a differential accelerometer. The goal of the experiment is to measure the Eoetvoes ratio sigma g/g (differential acceleration/common acceleration) with an accuracy goal of several parts in 10(exp 15). The estimated accuracy is about two orders of magnitude better than the present state of the art. The main goal of the study to be carried out under this grant is part of the flight definition of the experiment and laboratory testing of key components. The project involves an international cooperation in which the responsibility of the US side is the flight definition of the experimental facility while the responsibility of the non-US partners is the flight definition and laboratory prototyping of the differential acceleration detector.In summary, the experiment to be designed is for taking differential acceleration measurements with a high-sensitivity detector (the sensor) during free fall conditions lasting up to 30 s in a disturbance-free acceleration environment. The experiment strategy consists in letting the sensor free fall inside a few meters long (in the vertical direction) evacuated capsule that is falling simultaneously in the rarefied atmosphere after release from a helium balloon flying at a stratospheric altitude.

Particle Size Reduction in Geophysical Granular Flows: The Role of Rock Fragmentation

NASA Astrophysics Data System (ADS)

Bianchi, G.; Sklar, L. S.

2016-12-01

Particle size reduction in geophysical granular flows is caused by abrasion and fragmentation, and can affect transport dynamics by altering the particle size distribution. While the Sternberg equation is commonly used to predict the mean abrasion rate in the fluvial environment, and can also be applied to geophysical granular flows, predicting the evolution of the particle size distribution requires a better understanding the controls on the rate of fragmentation and the size distribution of resulting particle fragments. To address this knowledge gap we are using single-particle free-fall experiments to test for the influence of particle size, impact velocity, and rock properties on fragmentation and abrasion rates. Rock types tested include granodiorite, basalt, and serpentinite. Initial particle masses and drop heights range from 20 to 1000 grams and 0.1 to 3.0 meters respectively. Preliminary results of free-fall experiments suggest that the probability of fragmentation varies as a power function of kinetic energy on impact. The resulting size distributions of rock fragments can be collapsed by normalizing by initial particle mass, and can be fit with a generalized Pareto distribution. We apply the free-fall results to understand the evolution of granodiorite particle-size distributions in granular flow experiments using rotating drums ranging in diameter from 0.2 to 4.0 meters. In the drums, we find that the rates of silt production by abrasion and gravel production by fragmentation scale with drum size. To compare these rates with free-fall results we estimate the particle impact frequency and velocity. We then use population balance equations to model the evolution of particle size distributions due to the combined effects of abrasion and fragmentation. Finally, we use the free-fall and drum experimental results to model particle size evolution in Inyo Creek, a steep, debris-flow dominated catchment, and compare model results to field measurements.

The "Aachen fall prevention App" - a Smartphone application app for the self-assessment of elderly patients at risk for ground level falls.

PubMed

Rasche, Peter; Mertens, Alexander; Bröhl, Christina; Theis, Sabine; Seinsch, Tobias; Wille, Matthias; Pape, Hans-Christoph; Knobe, Matthias

2017-01-01

Fall incidents are a major problem for patients and healthcare. The "Aachen Fall Prevention App" (AFPA) represents the first mobile Health (mHealth) application (app) empowering older patients (persons 50+ years) to self-assess and monitor their individual fall risk. Self-assessment is based on the "Aachen Fall Prevention Scale," which consists of three steps. First, patients answer ten standardized yes-no questions (positive criterion ≥ 5 "Yes" responses). Second, a ten-second test of free standing without compensatory movement is performed (positive criterion: compensatory movement). Finally, during the third step, patients rate their subjective fall risk on a 10-point Likert scale, based on the results of steps one and two. The purpose of this app is (1) to offer a low-threshold service through which individuals can independently monitor their individual fall risk and (2) to collect data about how a patient-centered mHealth app for fall risk assessment is used in the field. The results represent the first year of an ongoing field study. From December 2015 to December 2016, 197 persons downloaded the AFPA (iOS ™ and Android ™ ; free of charge). N  = 111 of these persons voluntarily shared their data and thereby participated in the field study. Data from a final number of n  = 79 persons were analyzed due to exclusion criteria (age, missing objective fall risk, missing self-assessment). The objective fall risk and the self-assessed subjective risk measured by the AFPA showed a significant positive relationship. The "Aachen Fall Prevention App" (AFPA) is an mHealth app released for iOS and Android. This field study revealed the AFPA as a promising tool to raise older adults' awareness of their individual fall risk by means of a low-threshold patient-driven fall risk assessment tool.

Can a road-driven car outrace a free-falling car?

NASA Astrophysics Data System (ADS)

Castaño, Diego J.

2011-11-01

Motivated by an advertising scenario in which a luxury sports sedan races against a similar car falling under the influence of gravity, a calculation using undergraduate physics and calculus is performed to theoretically predict the outcome.

Enter AGU student contest to win free Fall Meeting registration

NASA Astrophysics Data System (ADS)

Smedley, Kara

2012-07-01

AGU is excited to announce its first Student Video and Student T-shirt Design competitions. This is an opportunity for students to display their artistic sides and share their creativity and love of science with the world. Entries could highlight an aspect of Earth or space science in an educational and/or entertaining way or showcase a career path in geophysical sciences. Winners of these student-only competitions will be awarded free registration to the 2012 Fall Meeting in San Francisco, Calif.

Energy and information near black hole horizons

DOE Office of Scientific and Technical Information (OSTI.GOV)

Freivogel, Ben, E-mail: benfreivogel@gmail.com

2014-07-01

The central challenge in trying to resolve the firewall paradox is to identify excitations in the near-horizon zone of a black hole that can carry information without injuring a freely falling observer. By analyzing the problem from the point of view of a freely falling observer, I arrive at a simple proposal for the degrees of freedom that carry information out of the black hole. An infalling observer experiences the information-carrying modes as ingoing, negative energy excitations of the quantum fields. In these states, freely falling observers who fall in from infinity do not encounter a firewall, but freely fallingmore » observers who begin their free fall from a location close to the horizon are ''frozen'' by a flux of negative energy. When the black hole is ''mined,'' the number of information-carrying modes increases, increasing the negative energy flux in the infalling frame without violating the equivalence principle. Finally, I point out a loophole in recent arguments that an infalling observer must detect a violation of unitarity, effective field theory, or free infall.« less

Vesiculation Processes During Transient and Sustained Explosive Activity at Halema'uma'u Crater, Kīlauea in 2008-2013.

NASA Astrophysics Data System (ADS)

Houghton, B. F.; Orr, T. R.; Taddeucci, J.; Carey, R.; Del Bello, E.; Scarlato, P.; Patrick, M. R.

2015-12-01

The 2008-2015 summit eruption within Halema'uma'u crater, Kilauea has been characterized by alternations of passive degassing with two styles of explosive activity, both frequently triggered by rock falls that perturb the free surface of magma in the vent. In the first, larger rock falls trigger second vesiculation of magma at depths up to 100 m below the free surface ejecting juvenile bomb and lapilli populations of very variable vesicularity. The second, the topic of this presentation, consists of intervals of minutes to tens-of-minutes duration of low fountaining activity often from multiple locations. Vents may migrate with time, first across the free surface to its margins, and then around the margins, in response to convection processes in the underlying melt. Analysis of short sequences of high-speed, high-resolution video footage shows that the sustained fountaining is maintained by not by a continuous discharge but rather by closely spaced bursting of two-to-five meter-wide bubbles. Bubbles accelerate through the free surface at velocities of 10 to 40 m/s disrupting the viscoelastic crust and forming large fall-back, lacework pyroclasts and smaller highly vesicular bombs and lapilli.

Test of the Equivalence Principle in an Einstein Elevator

NASA Technical Reports Server (NTRS)

Shapiro, Irwin I.

2002-01-01

The scientific goal of the experiment is to test the equality of gravitational and inertial mass (i.e., to test the Principle of Equivalence) by measuring the independence of the rate of fall of bodies from the composition of the falling body. The measurement is accomplished by measuring the relative displacement (or equivalently acceleration) of two falling bodies of different materials which are the proof masses of a differential accelerometer. The goal of the experiment is to measure the Eotvos ratio delta-g/g (differential acceleration/common acceleration) with an accuracy goal of a few parts in 10(exp 15). The estimated accuracy is about two orders of magnitude better than the present state of the art. The experiment is a null experiment in which a result different from zero will indicate a violation of the Equivalence Principle. The main goal of the study to be carried out under this grant is the flight definition of the experiment and bread boarding of critical components of the experiment that will enable us to be ready for the following phases of the project. The project involves an international cooperation in which the responsibility of the US side is the flight definition of the experimental facility while the responsibility of the non-US partners is the flight definition and laboratory prototyping of the differential acceleration detector. In summary, the experiment to be designed is for taking differential acceleration measurements with a high-sensitivity detector (the sensor) during free fall conditions lasting up to 30 s in a disturbance-free acceleration environment. The experiment strategy consists in letting the sensor free fall inside a few meters long (in the vertical direction) evacuated capsule that is falling simultaneously in the rarefied atmosphere after release from a helium balloon flying at a stratospheric altitude.

Testing the Equivalence Principle in an Einstein Elevator: Detector Dynamics and Gravity Perturbations

NASA Technical Reports Server (NTRS)

Hubbard, Dorthy (Technical Monitor); Lorenzini, E. C.; Shapiro, I. I.; Cosmo, M. L.; Ashenberg, J.; Parzianello, G.; Iafolla, V.; Nozzoli, S.

2003-01-01

We discuss specific, recent advances in the analysis of an experiment to test the Equivalence Principle (EP) in free fall. A differential accelerometer detector with two proof masses of different materials free falls inside an evacuated capsule previously released from a stratospheric balloon. The detector spins slowly about its horizontal axis during the fall. An EP violation signal (if present) will manifest itself at the rotational frequency of the detector. The detector operates in a quiet environment as it slowly moves with respect to the co-moving capsule. There are, however, gravitational and dynamical noise contributions that need to be evaluated in order to define key requirements for this experiment. Specifically, higher-order mass moments of the capsule contribute errors to the differential acceleration output with components at the spin frequency which need to be minimized. The dynamics of the free falling detector (in its present design) has been simulated in order to estimate the tolerable errors at release which, in turn, define the release mechanism requirements. Moreover, the study of the higher-order mass moments for a worst-case position of the detector package relative to the cryostat has led to the definition of requirements on the shape and size of the proof masses.

Free fall and the equivalence principle revisited

NASA Astrophysics Data System (ADS)

Pendrill, Ann-Marie

2017-11-01

Free fall is commonly discussed as an example of the equivalence principle, in the context of a homogeneous gravitational field, which is a reasonable approximation for small test masses falling moderate distances. Newton’s law of gravity provides a generalisation to larger distances, and also brings in an inhomogeneity in the gravitational field. In addition, Newton’s third law of action and reaction causes the Earth to accelerate towards the falling object, bringing in a mass dependence in the time required for an object to reach ground—in spite of the equivalence between inertial and gravitational mass. These aspects are rarely discussed in textbooks when the motion of everyday objects are discussed. Although these effects are extremely small, it may still be important for teachers to make assumptions and approximations explicit, to be aware of small corrections, and also to be prepared to estimate their size. Even if the corrections are not part of regular teaching, some students may reflect on them, and their questions deserve to be taken seriously.

Experiments Using Cell Phones in Physics Classroom Education: The Computer-Aided g Determination

NASA Astrophysics Data System (ADS)

Vogt, Patrik; Kuhn, Jochen; Müller, Sebastian

2011-09-01

This paper continues the collection of experiments that describe the use of cell phones as experimental tools in physics classroom education.1-4 We describe a computer-aided determination of the free-fall acceleration g using the acoustical Doppler effect. The Doppler shift is a function of the speed of the source. Since a free-falling objects speed is changing linearly with time, the Doppler shift is also changing with time. It is possible to measure this shift using software that is both easy to use and readily available. Students will use the time-dependency of the Doppler shift to experimentally determine the acceleration due to gravity by using a cell phone as a freely falling object emitting a sound with constant frequency.

Staying Mobile

MedlinePlus

... representatives are factory-trained accessibility specialists in ramp design and installation and will provide a free evaluation and consultation to determine what ramp is best for your needs. Video Series Free From Falls Some MS symptoms and treatments ...

The free fall of an apple: conceptual subtleties and implications for physics teaching

NASA Astrophysics Data System (ADS)

Assis, A. K. T.; Karam, R. A. S.

2018-05-01

The study of free fall is thoroughly present in physics teaching at all levels. From the point of view of Newtonian dynamics it appears to be extremely simple, as it consists of a two-body problem with a constant force generating a constant acceleration. However, there are several important conceptual subtleties and hidden assumptions involved in this problem, which are rarely discussed in educational settings. In this work we present some of these subtleties and argue that explicitly addressing them has significant pedagogical benefits.

When Does Air Resistance Become Significant in Projectile Motion?

NASA Astrophysics Data System (ADS)

Mohazzabi, Pirooz

2018-03-01

In an article in this journal, it was shown that air resistance could never be a significant source of error in typical free-fall experiments in introductory physics laboratories. Since projectile motion is the two-dimensional version of the free-fall experiment and usually follows the former experiment in such laboratories, it seemed natural to extend the same analysis to this type of motion. We shall find that again air resistance does not play a significant role in the parameters of interest in a traditional projectile motion experiment.

Intermediate states and structure evolution in the free-falling process of the dislocation in graphene

NASA Astrophysics Data System (ADS)

Wang, Shaofeng; Yao, Yin; Bai, Jianhui; Wang, Rui

2017-04-01

This paper investigated the intermediate states and the structure evolution of the dislocation in graphene when it falls freely from the saddle point of the energy landscape. The O-type dislocation, an unstable equilibrium structure located at the saddle point, is obtained from the lattice theory of the dislocation structure and improved by the ab initio calculation to take the buckling into account. Intermediate states along the kinetics path in the falling process are obtained from the ab initio simulation. Once the dislocation falls from the saddle point to the energy valley, this O-type dislocation transforms into the stable structure that is referred to as the B-type dislocation, and in the meantime, it moves a distance that equals half a Burgers vector. The structure evolution and the energy variation in the free-falling process are revealed explicitly. It is observed that rather than smooth change, a platform manifests itself in the energy curve. The unusual behaviour in the energy curve is mainly originated from symmetry breaking and bond formation in the dislocation core. The results can provide deep insight in the mechanism of the brittle feature of covalent materials.

Asia-Pacific Economic Update. Volume 1. Economic Strategy, Context and Performance

DTIC Science & Technology

2002-01-01

deficits and rigid exchange rate regimes contributed to financial turbulence and a disorderly free-fall of Asian foreign exchange rates . Floating exchange rate regimes are needed to optimize free international capital markets.

Physiological monitoring and analysis of a manned stratospheric balloon test program.

PubMed

Garbino, Alejandro; Blue, Rebecca S; Pattarini, James M; Law, Jennifer; Clark, Jonathan B

2014-02-01

The Red Bull Stratos Project consisted of incremental high altitude parachute jumps [maximum altitude 127,852 ft (38,969 m)] from a pressurized capsule suspended from a stratospheric helium-filled balloon. A physiological monitoring system was worn by the parachutist to provide operational medical and acceleration data and to record a unique set of data in a supersonic environment. Various physiological parameters, including heart rate (HR), respiratory rate (RR), skin temperature, and triaxial acceleration, were collected during the ascent, high altitude float, free fall, and parachute opening and descent stages of multiple low- and high altitude jumps. Physiologic data were synchronized with global positioning system (GPS) and audiovisual data for a comprehensive understanding of the environmental stressors experienced. HR reached maximum during capsule egress and remained elevated throughout free fall and landing. RR reached its maximum during free fall. Temperature data were unreliable and did not provide useful results. The highest accelerations parameters were recorded during parachute opening and during landing. During each high altitude jump, immediately after capsule egress, the parachutist experienced a few seconds of microgravity during which some instability occurred. Control was regained as the parachutist entered denser atmosphere. The high altitude environment resulted in extremely high vertical speeds due to little air resistance in comparison to lower altitude jumps with similar equipment. The risk for tumbling was highest at initial step-off. Physiological responses included elevated HR and RR throughout critical phases of free fall. The monitoring unit performed well despite the austere environment and extreme human performance activities.

29 CFR 1926.500 - Scope, application, and definitions applicable to this subpart.

Code of Federal Regulations, 2010 CFR

2010-07-01

...) Fall protection requirements for employees performing steel erection work (except for towers and tanks... protection systems, except in relation to steel erection activities. (b) Definitions. Anchorage means a... component parts. Load refusal is the point where the ultimate strength is exceeded. Free fall means the act...

Thought Experiments in Teaching Free-Fall Weightlessness: A Critical Review and an Exploration of Mercury's Behavior in "Falling Elevator"

ERIC Educational Resources Information Center

Balukovic, Jasmina; Slisko, Josip; Cruz, Adrián Corona

2017-01-01

Different "thought experiments" dominate teaching approaches to weightlessness, reducing students' opportunities for active physics learning, which should include observations, descriptions, explanations and predictions of real phenomena. Besides the controversy related to conceptual definitions of weight and weightlessness, we report…

Editors' Fall Picks

ERIC Educational Resources Information Center

Heilbrun, Margaret; McCormack, Heather; Katterjohn, Anna; Kuzyk, Raya; Roncevic, Mirela; Fox, Bette-Lee; Hoffert, Barbara

2009-01-01

"Library Journal's" review editors select fall titles readers won't want to miss--"Waiting on a Train: The Embattled Future of Passenger Rail Service" (James McCommons); "Happy" (Alex Lemon); "Free for All: Joe Papp, the Public, and the Greatest Theater Story Ever Told" (Kenneth Turan & Joseph Papp); "In My Father's Shadow: A Daughter Remembers…

Inertial measurements of free-living activities: assessing mobility to predict falls.

PubMed

Wang, Kejia; Lovell, Nigel H; Del Rosario, Michael B; Liu, Ying; Wang, Jingjing; Narayanan, Michael R; Brodie, Matthew A D; Delbaere, Kim; Menant, Jasmine; Lord, Stephen R; Redmond, Stephen J

2014-01-01

An exploratory analysis was conducted into how simple features, from acceleration at the lower back and ankle during simulated free-living walking, stair ascent and descent, correlate with age, the overall fall risk from a clinically validated Physiological Profile Assessment (PPA), and its sub-components. Inertial data were captured from 92 older adults aged 78-95 (42 female, mean age 84.1, standard deviation 3.9 years). The dominant frequency, peak width from Welch's power spectral density estimate, and signal variance along each axis, from each sensor location and for each activity were calculated. Several correlations were found between these features and the physiological risk factors. The strongest correlations were from the dominant frequency at the ankle along the mediolateral direction during stair ascent (Spearman's correlation coefficient p = - 0.45) with anterioposterior sway, and signal variance of the anterioposterior acceleration at the lower back during stair descent (p = - 0.45) with age. These findings should aid future attempts to classify activities and predict falls in older adults, based on true free-living data from a range of activities.

Hill-Burton Free and Reduced Cost Health Care

MedlinePlus

... applicant's income must fall within the annually published Poverty Guidelines of the U.S. Department of Health and ... your income is at or below the current Poverty Guidelines, facility services may be free. • If your ...

Ignition of deuterium-trtium fuel targets

DOEpatents

Musinski, Donald L.; Mruzek, Michael T.

1991-01-01

A method of igniting a deuterium-tritium ICF fuel target to obtain fuel burn in which the fuel target initially includes a hollow spherical shell having a frozen layer of DT material at substantially uniform thickness and cryogenic temperature around the interior surface of the shell. The target is permitted to free-fall through a target chamber having walls heated by successive target ignitions, so that the target is uniformly heated during free-fall to at least partially melt the frozen fuel layer and form a liquid single-phase layer or a mixed liquid/solid bi-phase layer of substantially uniform thickness around the interior shell surface. The falling target is then illuminated from exteriorly of the chamber while the fuel layer is at substantially uniformly single or bi-phase so as to ignite the fuel layer and release energy therefrom.

Ignition of deuterium-tritium fuel targets

DOEpatents

Musinski, D.L.; Mruzek, M.T.

1991-08-27

Disclosed is a method of igniting a deuterium-tritium ICF fuel target to obtain fuel burn in which the fuel target initially includes a hollow spherical shell having a frozen layer of DT material at substantially uniform thickness and cryogenic temperature around the interior surface of the shell. The target is permitted to free-fall through a target chamber having walls heated by successive target ignitions, so that the target is uniformly heated during free-fall to at least partially melt the frozen fuel layer and form a liquid single-phase layer or a mixed liquid/solid bi-phase layer of substantially uniform thickness around the interior shell surface. The falling target is then illuminated from exteriorly of the chamber while the fuel layer is at substantially uniformly single or bi-phase so as to ignite the fuel layer and release energy therefrom. 5 figures.

Capabilities and constraints of NASA's ground-based reduced gravity facilities

NASA Technical Reports Server (NTRS)

Lekan, Jack; Neumann, Eric S.; Sotos, Raymond G.

1993-01-01

The ground-based reduced gravity facilities of NASA have been utilized to support numerous investigations addressing various processes and phenomina in several disciplines for the past 30 years. These facilities, which include drop towers, drop tubes, aircraft, and sounding rockets are able to provide a low gravity environment (gravitational levels that range from 10(exp -2)g to 10(exp -6)g) by creating a free fall or semi-free fall condition where the force of gravity on an experiment is offset by its linear acceleration during the 'fall' (drop or parabola). The low gravity condition obtained on the ground is the same as that of an orbiting spacecraft which is in a state of perpetual free fall. The gravitational levels and associated duration times associated with the full spectrum of reduced gravity facilities including spaced-based facilities are summarized. Even though ground-based facilities offer a relatively short experiment time, this available test time has been found to be sufficient to advance the scientific understanding of many phenomena and to provide meaningful hardware tests during the flight experiment development process. Also, since experiments can be quickly repeated in these facilities, multistep phenomena that have longer characteristic times associated with them can sometimes be examined in a step-by-step process. There is a large body of literature which has reported the study results achieved through using reduced-gravity data obtained from the facilities.

Null result for violation of the equivalence principle with free-fall rotating gyroscopes

NASA Astrophysics Data System (ADS)

Luo, J.; Nie, Y. X.; Zhang, Y. Z.; Zhou, Z. B.

2002-02-01

The differential acceleration between a rotating mechanical gyroscope and a nonrotating one is directly measured by using a double free-fall interferometer, and no apparent differential acceleration has been observed at the relative level of 2×10-6. It means that the equivalence principle is still valid for rotating extended bodies, i.e., the spin-gravity interaction between the extended bodies has not been observed at this level. Also, to the limit of our experimental sensitivity, there is no observed asymmetrical effect or antigravity of the rotating gyroscopes as reported by Hayasaka et al.

Rotation in Free Fall of Rectangular Wings of Elongated Shape

NASA Technical Reports Server (NTRS)

Dupleich, Paul

1949-01-01

The present report of Mr. Dupleich is the summary of a very extensive experimental study of the well-known mechanical phenomenon: the rotation in free fall (* air, for instance) of more or less elongated rectangles cut out of paper or pasteboard. This phenomenon, the conditions for existence of which depend chiefly on the elongated of the small plate and its weight per unit area, is essentially an aerodynamic phenomenon and as such, raises questions of a certain interest to our department.We believe that the modern concepts of the mechanics of fluids do not have the range attributed to them.

De sitter space and perpetuum mobile

NASA Astrophysics Data System (ADS)

Akhmedov, Emil T.; Buividovich, P. V.; Singleton, Douglas A.

2012-04-01

The general arguments that any interacting nonconformal classical field theory in de Sitter space leads to the possibility of constructing a perpetuum mobile is given. The arguments are based on the observation that massive free falling particles can radiate other massive particles on the classical level as seen by the free falling observer. The intensity of the radiation process is not zero even for particles with any finite mass, i.e., with a wavelength which is within causal domain. Hence, we conclude that either de Sitter space cannot exist eternally or that one can build a perpetuum mobile.

De sitter space and perpetuum mobile

DOE Office of Scientific and Technical Information (OSTI.GOV)

Akhmedov, Emil T.; Buividovich, P. V.; Singleton, Douglas A.

2012-04-15

The general arguments that any interacting nonconformal classical field theory in de Sitter space leads to the possibility of constructing a perpetuum mobile is given. The arguments are based on the observation that massive free falling particles can radiate other massive particles on the classical level as seen by the free falling observer. The intensity of the radiation process is not zero even for particles with any finite mass, i.e., with a wavelength which is within causal domain. Hence, we conclude that either de Sitter space cannot exist eternally or that one can build a perpetuum mobile.

Alaska Department of Revenue - Tax Division - Front Page

Science.gov Websites

Production 538,323 5/24/2018 Online Services Revenue Online Revenue Online Pay Federal Taxes Online Free Pay Federal Taxes Online Free Annual Reports Spring 2018 Revenue Forecast Comparison of Fall 2017 and Spring

State Fall Prevention Coalitions as Systems Change Agents: An Emphasis on Policy.

PubMed

Schneider, Ellen C; Smith, Matthew Lee; Ory, Marcia G; Altpeter, Mary; Beattie, Bonita Lynn; Scheirer, Mary Ann; Shubert, Tiffany E

2016-03-01

Falls among older adults are an escalating public health issue, which requires a multidisciplinary and multilevel approach to affect systems change to effectively address this problem. The National Council on Aging established the Falls Free® Initiative, enfolding and facilitating statewide Fall Prevention Coalitions. Fall Free® activities included developing the State Policy Toolkit for Advancing Falls Prevention to promote sustainable change by supporting the dissemination and adoption of evidence-based strategies. To (1) determine if the policies being implemented were recommended and supported by the Toolkit, (2) identify the perceived barriers and facilitators to implementing policies, and (3) identify Coalitions' current and future fall prevention policy activities. A 63-item online survey was distributed to State Coalition Leads. Descriptive statistics (frequencies and counts) were used to describe Coalition characteristics and activities. Coalitions had several similarities, and varied greatly in their number of member organizations and members as well as meeting frequencies. Key activities included building partnerships, disseminating programs, and pursuing at least one of the eight National Council on Aging-recommended policy goals. The most commonly reported facilitator was active support from the Coalition Leads, whereas the lack of funding was the most cited barrier. This study serves as the first national census of empirical evidence regarding Falls Coalitions' composition, goals, and activities. Results indicate that Coalitions are actively pursuing evidence-based policies but could benefit from additional technical assistance and resources. Findings support the value of Toolkit recommendations by documenting what is feasible and being implemented. Knowledge about facilitators and barriers will inform future efforts to foster sustainable systems change in states with active Coalitions and encourage Coalitions in other states. © 2015 Society for Public Health Education.

Oscillating Droplets and Incompressible Liquids: Slow-Motion Visualization of Experiments with Fluids

ERIC Educational Resources Information Center

Vollmer, Michael; Mollmann, Klaus-Peter

2012-01-01

We present fascinating simple demonstration experiments recorded with high-speed cameras in the field of fluid dynamics. Examples include oscillations of falling droplets, effects happening upon impact of a liquid droplet into a liquid, the disintegration of extremely large droplets in free fall and the consequences of incompressibility. (Contains…

Drag crisis moderation by thin air layers sustained on superhydrophobic spheres falling in water.

PubMed

Jetly, Aditya; Vakarelski, Ivan U; Thoroddsen, Sigurdur T

2018-02-28

We investigate the effect of thin air layers naturally sustained on superhydrophobic surfaces on the terminal velocity and drag force of metallic spheres free falling in water. The surface of 20 mm to 60 mm steel or tungsten-carbide spheres is rendered superhydrophobic by a simple coating process that uses a commercially available hydrophobic agent. By comparing the free fall of unmodified spheres and superhydrophobic spheres in a 2.5 meter tall water tank, it is demonstrated that even a very thin air layer (∼1-2 μm) that covers the freshly dipped superhydrophobic sphere can reduce the drag force on the spheres by up to 80%, at Reynolds numbers from 10 5 to 3 × 10 5 , owing to an early drag crisis transition. This study complements prior investigations on the drag reduction efficiency of model gas layers sustained on heated metal spheres falling in liquid by the Leidenfrost effect. The drag reduction effects are expected to have significant implications for the development of sustainable air-layer-based energy saving technologies.

A remote-sensing, GIS-based approach to identify, characterize, and model spawning habitat for fall-run chum salmon in a sub-arctic, glacially fed river

USGS Publications Warehouse

Wirth, Lisa; Rosenberger, Amanda; Prakash, Anupma; Gens, Rudiger; Margraf, F. Joseph; Hamazaki, Toshihide

2012-01-01

At northern limits of a species’ distribution, fish habitat requirements are often linked to thermal preferences, and the presence of overwintering habitat. However, logistical challenges and hydrologic processes typical of glacial systems could compromize the identification of these habitats, particularly in large river environments. Our goal was to identify and characterize spawning habitat for fall-run chum salmon Oncorhynchus keta and model habitat selection from spatial distributions of tagged individuals in the Tanana River, Alaska using an approach that combined ground surveys with remote sensing. Models included braiding, sinuosity, ice-free water surface area (indicating groundwater influence), and persistent ice-free water (i.e., consistent presence of ice-free water for a 12-year period according to satellite imagery). Candidate models containing persistent ice-free water were selected as most likely, highlighting the utility of remote sensing for monitoring and identifying salmon habitat in remote areas. A combination of ground and remote surveys revealed spatial and temporal thermal characteristics of these habitats that could have strong biological implications. Persistent ice-free sites identified using synthetic aperture radar appear to serve as core areas for spawning fall chum salmon, and the importance of stability through time suggests a legacy of successful reproductive effort for this homing species. These features would not be captured with a one-visit traditional survey but rather required remote-sensing monitoring of the sites through time.

Free Workshop for Teachers at the 2013 AGU Fall Meeting

NASA Astrophysics Data System (ADS)

Tamalavage, Anne

2013-10-01

In keeping with its commitment to fostering the next generation of Earth and space scientists, AGU is partnering with the National Earth Science Teachers Association to hold the annual Geophysical Information for Teachers (GIFT) workshop at the 2013 AGU Fall Meeting. GIFT allows K-12 science educators (both classroom and informal) to hear from scientists about their latest Earth and space science research, explore new classroom resources for engaging students, and visit exhibits and technical sessions during the Fall Meeting.

Identification of the Spawning, Rearing and Migratory Requirements of Fall Chinook Salmon in the Columbia River Basin, Annual Report 1992.

DOE Office of Scientific and Technical Information (OSTI.GOV)

Rondorf, Dennis W.; Miller, William H.

1994-03-01

This document is the 1992 annual progress report for selected studies of fall chinook Salmon Oncorhynchus tshawytscha conducted by the National Biological Survey (NBS) and the US Fish and Wildlife Service. The decline in abundance of fall chinook salmon in the Snake River basin has become a growing concern. Effective recovery efforts for fall chinook salmon cannot be developed until we increase our knowledge of the factors that are limiting the various life history stages. This study attempts to identify those physical and biological factors which influence spawning of fall chinook salmon in the free-flowing Snake River and their rearingmore » and seaward migration through Columbia River basin reservoirs.« less

Identification of the Spawning, Rearing, and Migratory Requirements of Fall Chinook Salmon in the Columbia River Basin, 1991 Annual Progress Report.

DOE Office of Scientific and Technical Information (OSTI.GOV)

Rondorf, Dennis W.; Miller, William H.

1993-07-01

This document is the 1991 annual progress report for selected studies of fall chinook salmon Oncorhynchus tshawytscha conducted by the US Fish and Wildlife Service. The decline in abundance of fall chinook salmon in the Snake River basin has become a growing concern. In April 1992, Snake River fall chinook salmon were listed as ``threatened`` under the Endangered Species Act. Effective recovery efforts for fall chinook salmon can not be developed until we increase our knowledge of the factors that are limiting the various life history stages. This study attempts to identify those physical and biological factors which influence spawningmore » of fall chinook salmon in the free-flowing Snake River and their rearing and seaward migration through Columbia River basin reservoirs.« less

Weinberger-Powell and Transformation: Perceptions of American Power from the Fall of Saigon to the Fall of Baghdad

DTIC Science & Technology

2006-06-01

New York, NY: Pleiades Publishing, 2004), 1-16. 148 Fukuyama, Francis. The End of History and the Last Man (New York, NY: The Free Press, 1992...New York, NY: Pleiades Publishing, 2004. Clausewitz, Carl von. On War. trans. by Michael Howard and Peter Paret. Princeton, NJ: Princeton

Measurement of "g" Using a Flashing LED

ERIC Educational Resources Information Center

Terzella, T.; Sundermier, J.; Sinacore, J.; Owen, C.; Takai, H.

2008-01-01

In one of the classic free-fall experiments, a small mass is attached to a strip of paper tape and both are allowed to fall through a spark timer, where sparks are generated at regular time intervals. Students analyze marks (dots) left on the tape by the timer, thereby generating distance-versus-time data, which they analyze to extract the…

Laboratory Test of the Galilean Universality of the Free Fall Experiment

ERIC Educational Resources Information Center

Christensen, Rasmus S.; Teiwes, Ricky; Petersen, Steffen V.; Uggerhøj, Ulrik I.; Jacoby, Bo

2014-01-01

There is a popular myth that Galileo dropped two objects of the same shape but different mass, noted their equal fall time, and concluded that gravitational motion is independent of the mass of the object. This paper demonstrates that this experiment--if actually performed--most likely would have yielded a different result and thus with modern…

Students: Design a T-Shirt or Submit a Video to Win 2013 Fall Meeting Registration

NASA Astrophysics Data System (ADS)

Noreika, J. Matt

2013-05-01

For the second consecutive year, AGU is holding its annual Student T-Shirt Design and Student Video competitions. The two contests, running simultaneously, offer AGU student members a chance to express their creative side. The winners will receive free registration for the 2013 Fall Meeting in San Francisco, Calif.

Characteristics of patients who stop falling after a risk-based multidisciplinary intervention initiated in a geriatric day hospital.

PubMed

Flabeau, O; Laurendeau, G; Laksir, H; Castaings-Pelet, S; Harston, S; Bourdel-Marchasson, I

2013-02-01

Multidisciplinary interventions for fallers have provided conflicting results in part due to the diversity of fallers' profiles. to determine the characteristics of the subgroup of patients with a positive response to a multidisciplinary fall prevention program initiated in a geriatric day hospital. Prospective observational study in day hospital. Patients > 75 years referred for falls during the last 3 months benefited from a multidisciplinary assessment to record their characteristics at baseline and to tailor a risk-based multidisciplinary intervention for fall prevention. Patients free from falls at the 3rd or 6th month were compared to persistent fallers for baseline characteristics. Sixty-nine patients were assessed at baseline (mean age 85.2 y (SD=0.6)), 44 at the 3rd month and 21 at the 6th month. Baseline characteristics of the patients free from falls at the 3rd month were the lower number of previous non-serious falls (p=0.013), living in nursing home (p=0.045), a higher Berg balance score (p=0.02) and a better mental health-related quality of life (M HQol, p=0.045). On multivariate analysis restricted to home-dwelling patients, the positive predictive factors were less isolation at home (OR=0.028, 95%CI [0-0.813], p=0.037), a lower number of non-serious previous falls (OR= 0.526 [0.309- 0.894], p=0.018), a better M HQol (OR=1.205 [1.000-1.452], p=0.050) and a trend for younger age (OR= 0.662, [0.426-1.027], p=0.066). Being able to call upon a support person (familial or institutional) to apply advice and a less serious risk of falling may be preliminary conditions for success in a multidisciplinary intervention initiated in a day hospital.

The influence of gravitoinertial force level on oculomotor and perceptual responses to Coriolis, cross-coupling stimulation

NASA Technical Reports Server (NTRS)

Dizio, Paul; Lackner, James R.; Evanoff, John N.

1987-01-01

The goal of the present experiment was to determine whether gravitoinertial force magnitude influences oculomotor and perceptual responses to Coriolis cross-coupling stimulation. Blindfolded subjects who were rotating at constant velocity were asked to make standardized head movements during the free-fall and high-force phases of parabolic flight, and the characteristics of their horizontal nystagmus and the magnitude of their experienced self-motion were measured. Both responses were less intense in the free-fall periods than in the high-force periods. These findings suggest that the response to semicircular canal stimulation depends on the background level of gravitoinertial force.

Using Tracker to understand ‘toss up’ and free fall motion: a case study

NASA Astrophysics Data System (ADS)

Wee, Loo Kang; Kia Tan, Kim; Leong, Tze Kwang; Tan, Ching

2015-07-01

This paper reports the use of Tracker as a computer-based learning tool to support effective learning and teaching of ‘toss up’ and free fall motion for beginning secondary three (15 year-old) students. The case study involved (N = 123) students from express pure physics classes at a mainstream school in Singapore. We used eight multiple-choice questions pre- and post-test to gauge the impact on learning. The experimental group showed learning gains of d = 0.79  ±  0.23 (large effect) for Cohen’s d effect size analysis, and gains with a gradient of  total = 0.42  ±  0.08 (medium gain) above the traditional baseline value of  non interactive = 0.23 for Hake’s normalized gain regression analysis. This applied to all of the teachers and students who participated in this study. Our initial research findings suggest that allowing learners to relate abstract physics concepts to real life through coupling traditional video analysis with video modelling might be an innovative and effective method for teaching and learning about free fall motion.

Towards Testing General Relativity with a dual species interferometer

NASA Astrophysics Data System (ADS)

Schlippert, Dennis; Hartwig, Jonas; Tiarks, Daniel; Velte, Ulrich; Ganske, Sven; Ertmer, Wolfgang; Rasel, Ernst M.

2012-06-01

We report on our work directed towards a dual species matter-wave interferometer for performing a differential measurement of the acceleration of free falling ^87Rb and ^39K atoms to test Einstein's equivalence principle (universality of free fall). Based on minimal Standard Model Extension calculations this combination of test masses is more sensitive to composition based equivalence principle violating effects than, e.g. ^85Rb-^87Rb. During free fall, a Mach-Zehnder type interferometry sequence employing stimulated Raman transitions is applied synchronously for both species, achieving high common noise rejection. With an expected single shot resolution of 5x10-8g the apparatus will allow for studying systematics at the 10-9g level after 100 s integration time. Post-correction methods for high vibrational noise environments are investigated. To assure well defined starting conditions the two species will be trapped in an optical dipole trap. The properties of this trap at 2 μm allow for fast and efficient laser cooling, use of evaporative and sympathetic cooling techniques is possible. We will show the enviromental noise limited performance of the single species Rb gravimeter and the progress of the implementation of the K gravimeter.

Rolling and slipping down Galileo{close_quote}s inclined plane: Rhythms of the spheres

DOE Office of Scientific and Technical Information (OSTI.GOV)

Crawford, F.S.

In ``Two New Sciences`` (TNS) Galileo presents a number of theorems and propositions for smooth solid spheres released from rest and rolling a distance {ital d} in time {ital t} down an incline of height {ital H} and length {ital L}. We collect and summarize his results in a single grand proportionality {ital P}: {ital d}{sub 1}/{ital d}{sub 2}=({ital t}{sup 2}{sub 1}/{ital t}{sup 2}{sub 2})({ital H}/{ital L}){sub 1}/({ital H}/{ital L}){sub 2}. ({ital P}) From TNS it is clear that what we call {ital P} is assumed by Galileo to hold for all inclinations including vertical free fall with {ital H}/{italmore » L}=1. But in TNS he describes only experiments with gentle inclinations {ital H}/{ital L}{lt}1/2. Indeed he cannot have performed the vertical free fall ({ital H}={ital L}) experiment, because we (moderns) know that as we increase {ital H}/{ital L}, {ital P} starts to break down when {ital H}/{ital L} exceeds about 0.5, because the sphere, which rolls without slipping for small {ital H}/{ital L}, starts to slip, whence {ital d} starts to exceed the predictions of {ital P}, becoming too large by a factor of 7/5 for vertical free fall at {ital H}/{ital L}=1. In 1973 Drake and in 1975 Drake and MacLachlan published their analysis of a previously unpublished experiment that Galileo performed that (without his realizing it) directly compared rolling without slipping to free fall. In the experiment, a sphere that has gained speed {ital v}{sub 1} while rolling down a gentle incline is deflected so as to be launched horizontally with speed {ital v}{sub 1} into a free fall orbit discovered by Galileo to be a parabola. The measured horizontal distance {ital X}{sub 2} traveled in this parabolic orbit (for a given vertical distance fallen to the floor) was smaller than he expected, by a factor 0.84. But that is exactly what we (moderns) expect, since we know that Galileo did not appreciate the difference between rolling without slipping, and slipping on a frictionless surface.« less

Structural and Biomechanical Adaptations to Free-Fall Landing in Hindlimb Cortical Bone of Growing Female Rats.

PubMed

Lin, Hsin-Shih; Wang, Ho-Seng; Chiu, Hung-Ta; Cheng, Kuang-You B; Hsu, Ar-Tyan; Huang, Tsang-Hai

2018-06-01

The purpose of the study was to investigate the adaptation process of hindlimb cortical bone subjected to free-fall landing training. Female Wistar rats (7 weeks old) were randomly assigned to four landing (L) groups and four age-matched control (C) groups (n = 12 per group): L1, L2, L4 L8, C1, C2, C4 and C8. Animals in the L1, L2, L4 and L8 groups were respectively subjected to 1, 2, 4 and 8 weeks of free-fall-landing training (40 cm height, 30 times/day and 5 days/week) while the C1, C2, C4 and C8 groups served as age-matched control groups. The tibiae of the L8 group were higher in cortical bone mineral content (BMC) than those in the C8 group (p < 0.05). Except for the higher bone mineralization over bone surface ratio (MS/BS, %) shown in the tibiae of the L1 group (p < 0.05), dynamic histomorphometry in the tibial and femoral cortical bone showed no difference between landing groups and their age-matched control groups. In the femora, the L1 group was lower than the C1 group in cortical bone area (Ct.Ar) and cortical thickness (Ct.Th) (p < 0.05); however, the L4 group was higher than the C4 group in Ct.Ar and Ct.Th (p <0 .05). In the tibiae, the moment of inertia about the antero-posterior axis ( I ap ), Ct.Ar and Ct.Th was significantly higher in the L8 group than in the C8 group (p < 0.05). In biomechanical testing, fracture load (FL) of femora was lower in the L1 group than in the C1 group (p < 0.05). Conversely, yield load (YL), FL and yield load energy (YE) of femora, as well as FL of tibiae were all significantly higher in the L8 group than in the C8 group (p < 0.05). Free-fall landing training may initially compromise bone material. However, over time, the current free-fall landing training induced improvements in biomechanical properties and/or the structure of growing bones.

Efficient source separation algorithms for acoustic fall detection using a microsoft kinect.

PubMed

Li, Yun; Ho, K C; Popescu, Mihail

2014-03-01

Falls have become a common health problem among older adults. In previous study, we proposed an acoustic fall detection system (acoustic FADE) that employed a microphone array and beamforming to provide automatic fall detection. However, the previous acoustic FADE had difficulties in detecting the fall signal in environments where interference comes from the fall direction, the number of interferences exceeds FADE's ability to handle or a fall is occluded. To address these issues, in this paper, we propose two blind source separation (BSS) methods for extracting the fall signal out of the interferences to improve the fall classification task. We first propose the single-channel BSS by using nonnegative matrix factorization (NMF) to automatically decompose the mixture into a linear combination of several basis components. Based on the distinct patterns of the bases of falls, we identify them efficiently and then construct the interference free fall signal. Next, we extend the single-channel BSS to the multichannel case through a joint NMF over all channels followed by a delay-and-sum beamformer for additional ambient noise reduction. In our experiments, we used the Microsoft Kinect to collect the acoustic data in real-home environments. The results show that in environments with high interference and background noise levels, the fall detection performance is significantly improved using the proposed BSS approaches.

Experimental demonstration that a free-falling aerosol particle obeys a fluctuation theorem

NASA Astrophysics Data System (ADS)

Wong, Chun-Shang; Goree, J.; Gopalakrishnan, Ranganathan

2018-05-01

We investigate the fluctuating motion of an aerosol particle falling in air. Using a Millikan-like setup, we tracked a 1-μ m sphere falling at its terminal velocity. We observe occurrences of particles undergoing upward displacements against the force of gravity, so that negative work is done briefly. These negative-work events have a probability that is shown to obey the work fluctuation theorem. This experimental confirmation of the theorem's applicability to aerosols leads us to develop and demonstrate an application: an in situ measurement of an aerosol particle's mass.

Surface Oscillations of a Free-Falling Droplet of an Ideal Fluid

NASA Astrophysics Data System (ADS)

Kistovich, A. V.; Chashechkin, Yu. D.

2018-03-01

According to observations, drops freely falling in the air under the action of gravity are deformed and oscillate in a wide range of frequencies and scales. A technique for calculating surface axisymmetric oscillations of a deformed droplet in the linear approximation under the assumption that the amplitude and wavelength are small when compared to the droplet diameter is proposed. The basic form of an axisymmetric droplet is chosen from observations. The calculation results for surface oscillations agree with recorded data on the varying shape of water droplets falling in the air.

29 CFR Appendix C to Subpart M of... - Personal Fall Arrest Systems

Code of Federal Regulations, 2014 CFR

2014-07-01

... appendix D of this subpart, the test methods listed here in appendix C can also be used to assist employers... about the system based on its performance during testing so that the employer can know if the system... deceleration device of the self-retracting type since this can result in additional free fall for which the...

29 CFR Appendix C to Subpart M of... - Personal Fall Arrest Systems

Code of Federal Regulations, 2013 CFR

2013-07-01

... appendix D of this subpart, the test methods listed here in appendix C can also be used to assist employers... about the system based on its performance during testing so that the employer can know if the system... deceleration device of the self-retracting type since this can result in additional free fall for which the...

29 CFR Appendix C to Subpart M of... - Personal Fall Arrest Systems

Code of Federal Regulations, 2012 CFR

2012-07-01

... appendix D of this subpart, the test methods listed here in appendix C can also be used to assist employers... about the system based on its performance during testing so that the employer can know if the system... deceleration device of the self-retracting type since this can result in additional free fall for which the...

Touching Ghosts: Observing Free Fall from an Infalling Frame of Reference into a Schwarzschild Black Hole

ERIC Educational Resources Information Center

Augousti, A. T.; Gawelczyk, M.; Siwek, A.; Radosz, A.

2012-01-01

The problem of communication between observers in the vicinity of a black hole in a Schwarzschild metric is considered. The classic example of an infalling observer Alice and a static distant mother station (MS) is extended to include a second infalling observer Bob, who follows Alice in falling towards the event horizon. Kruskal coordinates are…

Free-fall dynamics of a pair of rigidly linked disks

NASA Astrophysics Data System (ADS)

Kim, Taehyun; Chang, Jaehyeock; Kim, Daegyoum

2018-03-01

We investigate experimentally the free-fall motion of a pair of identical disks rigidly connected to each other. The three-dimensional coordinates of the pair of falling disks were constructed to quantitatively describe its trajectory, and the flow structure formed by the disk pair was identified by using dye visualization. The rigidly linked disk pair exhibits a novel falling pattern that creates a helical path with a conical configuration in which the lower disk rotates in a wider radius than the upper disk with respect to a vertical axis. The helical motion occurs consistently for the range of disk separation examined in this study. The dye visualization reveals that a strong, noticeable helical vortex core is generated from the outer tip of the lower disk during the helical motion. With an increasing length ratio, which is the ratio of the disk separation to the diameter of the disks, the nutation angle and the rate of change in the precession angle that characterize the combined helical and conical kinematics decrease linearly, whereas the pitch of the helical path increases linearly. Although all disk pairs undergo this helical motion, the horizontal-drift patterns of the disk pair depend on the length ratio.

Time-dependent, optically thick accretion onto a black hole

NASA Technical Reports Server (NTRS)

Gilden, D. L.; Wheeler, J. C.

1980-01-01

A fully relativistic hydrodynamics code which incorporates diffusive radiation transport is used to study time-dependent, spherically symmetric, optically thick accretion onto a black hole. It is found that matter free-falls into the hole regardless of whether the diffusion time scale is longer or shorter than the dynamical time. Nonadiabatic heating due to magnetic field reconnection is included. The internal energy thus generated affects the flow in a purely relativistic way, again ensuring free-fall collapse of the inflowing matter. Any matter enveloping a black hole will thus be swallowed on a dynamical time scale with relatively small net release of energy. The inclusion of angular momentum will not necessarily affect this conclusion.

Free-falling Crystals: Biological Macromolecular Crystal Growth Studies in Low Earth Orbit

NASA Technical Reports Server (NTRS)

Judge, Russell A.; Snell, E. H.; Pusey, M. L.; Whitaker, Ann F. (Technical Monitor)

2001-01-01

Spacecraft orbiting the earth experience a reduced acceleration environment due to being in a state of continuous free-fall. This state colloquially termed microgravity, has produced improved X-ray diffraction quality crystals of biological macromolecules. Improvements in X-ray diffraction resolution (detail) or signal to noise, provide greater detail in the three-dimensional molecular structure providing information about the molecule, how it works, how to improve its function or how to impede it. Greater molecular detail obtained by crystallization in microgravity, has important implications for structural biology. In this article we examine the theories behind macromolecule crystal quality improvement in microgravity using results obtained from studies with the model protein, chicken egg white lysozyme.

Nonsensical choices? Fall armyworm moths choose seemingly best or worst hosts for their larvae, but neonate larvae make their own choices.

PubMed

Rojas, Julio C; Kolomiets, Michael V; Bernal, Julio S

2018-01-01

Selecting optimal host plants is critical for herbivorous insects, such as fall armyworm (Spodoptera frugiperda), an important maize pest in the Americas and Africa. Fall armyworm larvae are presumed to have limited mobility, hence female moths are presumed to be largely responsible for selecting hosts. We addressed host selection by fall armyworm moths and neonate and older (3rd-instar) larvae, as mediated by resistance and herbivory in maize plants. Thus, we compared discrimination among three maize cultivars with varying degrees of resistance to fall armyworm, and between plants subjected or not to two types of herbivory. The cultivars were: (i) susceptible, and deficient in jasmonic acid (JA) production and green leaf volatiles (GLV) emissions (inbred line B73-lox10); (ii) modestly resistant (B73), and; (iii) highly resistant (Mp708). The herbivory types were: (i) ongoing (= fall armyworm larvae present), and; (ii) future (= fall armyworm eggs present). In choice tests, moths laid more eggs on the highly resistant cultivar, and least on the susceptible cultivar, though on those cultivars larvae performed poorest and best, respectively. In the context of herbivory, moths laid more eggs: (i) on plants subject to versus free of future herbivory, regardless of whether plants were deficient or not in JA and GLV production; (ii) on plants subject versus free of ongoing herbivory, and; (iii) on plants not deficient in compared to deficient in JA and GLV production. Neonate larvae dispersed aerially from host plants (i.e. ballooned), and most larvae colonized the modestly resistant cultivar, and fewest the highly resistant cultivar, suggesting quasi-directional, directed aerial descent. Finally, dispersing older larvae did not discriminate among the three maize cultivars, nor between maize plants and (plastic) model maize plants, suggesting random, visually-oriented dispersal. Our results were used to assemble a model of host selection by fall armyworm moths and larvae, including recommendations for future research.

Identification of the Spawning, Rearing, and Migratory Requirements of Fall Chinook Salmon in the Columbia River Basin, Annual Report 1993.

DOE Office of Scientific and Technical Information (OSTI.GOV)

Rondorf, Dennis W.; Tiffan, Kenneth F.

1994-12-01

Recovery efforts for the endangered fall chinook salmon necessitates knowledge of the factors limiting the various life history stages. This study attempts to identify those physical and biological factors which affect spawning of the fish in the free-flowing Snake River and their rearing seward migration through Columbia River basin reservoirs. The spawning was generally a November event in 1993, with some activity in late Oct. and early Dec. Spawning habitat availability was assessed by applying hydraulic and habitat models to known fall chinook salmon spawning sites. Juveniles were seined and PIT tagged in the free-flowing Snake River, and in themore » Columbia River in he Hanford Reach and in McNary Reservoir. Subyearling fish were marked at McNary Dam to relate river flow and migration patterns of juveniles to adult returns. Hydroacoustic surveys were conducted on McNary and John Day reservoirs and in net pens.« less

Fall prevention in central coast community pharmacies.

PubMed

Stuart, Gina M; Kale, Helen L

2018-04-19

Fall injuries among people aged 65 years and over (older people) cause substantial health decline and cost to the health system. In 2009 in New South Wales, 25.6% of older people fell in the previous year, and 10.7% (32 000) were hospitalised. Pharmacists are trusted professionals, who interact extensively with older people and have potential to augment fall prevention in pharmacies. This brief report describes how professional development improved pharmacist's knowledge and confidence in fall prevention, encouraged implementation of fall prevention plans and facilitated the provision of brief fall prevention interventions for older clients, after identification of fall risk. In 2014, pharmacists from all Central Coast pharmacies (n = 76) were invited to free, continuing professional development (CPD) in fall prevention. It provided education and resources to identify clients' fall risk, conduct brief fall prevention interventions and implement fall prevention health promotion plans (FPHPP). Pharmacists completed written: Baseline and post-workshop questionnaires to assess changes in pharmacist's knowledge and confidence, and existing fall prevention in pharmacies. Logs of client fall risk and brief fall prevention interventions offered to clients. Four-month follow-up questionnaires to assess implementation of FPHPPs and pharmacy practice changes. Pharmacists representing 36% of pharmacies participated. At four-month follow-up, 67% had implemented FPHPPs, and 62% delivered brief interventions determined by client fall risk. Fall prevention in pharmacies can be augmented through locally provided CPD tailored for pharmacists. SO WHAT?: This model could increase fall prevention reach. It is transferable to settings where health professionals provide services to older adults and require reregistration through professional development. © 2018 Australian Health Promotion Association.

Developing a Graphical Tool for Students to Understand Air Resistance and Free Fall: When Heavier Objects "Do" Fall Faster

ERIC Educational Resources Information Center

Ferreira, Annalize; Seyffert, Albertus S.; Lemmer, Miriam

2017-01-01

Many students find it difficult to apply certain physics concepts to their daily lives. This is especially true when they perceive a principle taught in physics class as being in conflict with their experience. An important instance of this occurs when students are instructed to ignore the effect of air resistance when solving kinematics problems.…

Falling PC Solitaire Cards: An Open-Inquiry Approach

ERIC Educational Resources Information Center

Gonzalez-Espada, Wilson J.

2012-01-01

Many of us have played the PC Solitaire game that comes as standard software in many computers. Although I am not a great player, occasionally I win a game or two. The game celebrates my accomplishment by pushing the cards forward, one at a time, falling gracefully in what appears to look like a parabolic path in a drag-free environment. One day,…

Novel Hierarchical Fall Detection Algorithm Using a Multiphase Fall Model.

PubMed

Hsieh, Chia-Yeh; Liu, Kai-Chun; Huang, Chih-Ning; Chu, Woei-Chyn; Chan, Chia-Tai

2017-02-08

Falls are the primary cause of accidents for the elderly in the living environment. Reducing hazards in the living environment and performing exercises for training balance and muscles are the common strategies for fall prevention. However, falls cannot be avoided completely; fall detection provides an alarm that can decrease injuries or death caused by the lack of rescue. The automatic fall detection system has opportunities to provide real-time emergency alarms for improving the safety and quality of home healthcare services. Two common technical challenges are also tackled in order to provide a reliable fall detection algorithm, including variability and ambiguity. We propose a novel hierarchical fall detection algorithm involving threshold-based and knowledge-based approaches to detect a fall event. The threshold-based approach efficiently supports the detection and identification of fall events from continuous sensor data. A multiphase fall model is utilized, including free fall, impact, and rest phases for the knowledge-based approach, which identifies fall events and has the potential to deal with the aforementioned technical challenges of a fall detection system. Seven kinds of falls and seven types of daily activities arranged in an experiment are used to explore the performance of the proposed fall detection algorithm. The overall performances of the sensitivity, specificity, precision, and accuracy using a knowledge-based algorithm are 99.79%, 98.74%, 99.05% and 99.33%, respectively. The results show that the proposed novel hierarchical fall detection algorithm can cope with the variability and ambiguity of the technical challenges and fulfill the reliability, adaptability, and flexibility requirements of an automatic fall detection system with respect to the individual differences.

Novel Hierarchical Fall Detection Algorithm Using a Multiphase Fall Model

PubMed Central

Hsieh, Chia-Yeh; Liu, Kai-Chun; Huang, Chih-Ning; Chu, Woei-Chyn; Chan, Chia-Tai

2017-01-01

Falls are the primary cause of accidents for the elderly in the living environment. Reducing hazards in the living environment and performing exercises for training balance and muscles are the common strategies for fall prevention. However, falls cannot be avoided completely; fall detection provides an alarm that can decrease injuries or death caused by the lack of rescue. The automatic fall detection system has opportunities to provide real-time emergency alarms for improving the safety and quality of home healthcare services. Two common technical challenges are also tackled in order to provide a reliable fall detection algorithm, including variability and ambiguity. We propose a novel hierarchical fall detection algorithm involving threshold-based and knowledge-based approaches to detect a fall event. The threshold-based approach efficiently supports the detection and identification of fall events from continuous sensor data. A multiphase fall model is utilized, including free fall, impact, and rest phases for the knowledge-based approach, which identifies fall events and has the potential to deal with the aforementioned technical challenges of a fall detection system. Seven kinds of falls and seven types of daily activities arranged in an experiment are used to explore the performance of the proposed fall detection algorithm. The overall performances of the sensitivity, specificity, precision, and accuracy using a knowledge-based algorithm are 99.79%, 98.74%, 99.05% and 99.33%, respectively. The results show that the proposed novel hierarchical fall detection algorithm can cope with the variability and ambiguity of the technical challenges and fulfill the reliability, adaptability, and flexibility requirements of an automatic fall detection system with respect to the individual differences. PMID:28208694

To crash or not to crash: how do hoverflies cope with free-fall situations and weightlessness?

PubMed

Goulard, Roman; Vercher, Jean-Louis; Viollet, Stéphane

2016-08-15

Insects' aptitude to perform hovering, automatic landing and tracking tasks involves accurately controlling their head and body roll and pitch movements, but how this attitude control depends on an internal estimation of gravity orientation is still an open question. Gravity perception in flying insects has mainly been studied in terms of grounded animals' tactile orientation responses, but it has not yet been established whether hoverflies use gravity perception cues to detect a nearly weightless state at an early stage. Ground-based microgravity simulators provide biologists with useful tools for studying the effects of changes in gravity. However, in view of the cost and the complexity of these set-ups, an alternative Earth-based free-fall procedure was developed with which flying insects can be briefly exposed to microgravity under various visual conditions. Hoverflies frequently initiated wingbeats in response to an imposed free fall in all the conditions tested, but managed to avoid crashing only in variably structured visual environments, and only episodically in darkness. Our results reveal that the crash-avoidance performance of these insects in various visual environments suggests the existence of a multisensory control system based mainly on vision rather than gravity perception. © 2016. Published by The Company of Biologists Ltd.

Newtonian Analysis of a Folded Chain Drop

NASA Astrophysics Data System (ADS)

Mungan, Carl E.

2018-05-01

Consider a chain of length L that hangs in a U shape with end A fixed to a rigid support and free end E released from rest starting from the same initial height (call it y = 0) as A. Figure 1 sketches the chain after end E has fallen a distance y. Points O and A are assumed to be close enough to each other and the chain flexible enough that the radius of curvature r at the bottom point C can be taken to be negligibly small (compared to the length of the chain). The problem is to compare the speed of descent v(y) = dy/dt of the free end E of the chain to the speed vfree(y )=√{2 g y } of a free-falling point mass that has descended the same distance y. If v(y) > vfree (y) for all y > 0, then, in a race to fall any arbitrary distance Y (where 0 < Y < L), the chain end E will always beat a simultaneously released point mass, because the fall time t for E will be shorter than tfree for the point mass, t = ∫0 Y d/y v (y )

Chromium Toxicity Test for Fall Chinook Salmon (Oncorhynchus tshawytscha) Using Hanford Site Groundwater: Onsite Early Life-Stage Toxicity Evaluation

DOE Office of Scientific and Technical Information (OSTI.GOV)

Patton, Gregory W; Dauble, Dennis D; Chamness, Mickie A

The objective of this study was to evaluate site-specific effects for early life-stage (eyed eggs to free swimming juveniles) fall chinook salmon that might be exposed to hexavalent chromium from Hanford groundwater sources. Our exposure conditions included hexavalent chromium obtained from Hanford groundwater wells near the Columbia River, Columbia River water as the diluent, and locally adapted populations of fall chinook salmon. This report describes both a 96-hr pretest using rainbow trout eggs and an early life-stage test beginning with chinook salmon eggs.

Green Team Hosts Plant Swap to Encourage Gardening | Poster

Cancer.gov

By Carolynne Keenan, Contributing Writer What started out as a way for Howard Young, Ph.D., to thin out his garden last fall turned into the NCI at Frederick Green Team’s Plant Swap. The group held its Fall Plant Swap on October 24, encouraging all members of the Fort Detrick community to pick up a free plant or swap a plant of theirs for another. “Those who love to garden introduce others to the joy of gardening,” said Dolores Winterstein, a member of the Green Team and the coordinator of the Fall Plant Swap.

Dynamic Weighing Experiments—The Way to New Physics of Gravitation

NASA Astrophysics Data System (ADS)

Dmitriev, A. L.; Nikushchenko, E. M.; Bulgakova, S. A.

2010-01-01

Dynamic weighing is a measuring of size of the average gravity force acting on a test body which is in the state of accelerated movement. The acceleration of a body, or its microparticles, can be caused both by forces of gravitation, and by a direct, electromagnetic in nature, influence on the part of other bodies. It is just dynamic weighing of bodies which is informative in studying the features of electromagnetic and gravitational forces interaction. The report gives a brief review of results of experiments with weighing of accelerated moving bodies—in case of shock phenomena, in state of rotation, and in heating. Special attention is given to measurements of free fall accelerations of a mechanical rotor. In majority of the laboratory experiments executed with the purpose of checking the equivalence principle, the axis of a rotor was oriented verticallly. In our experiment we measured the free fall accelerations of the closed container inside which a mechanical rotor (gyroscope) with a horizontal axis of rotation was installed. There was observed an appreciable, essentially exceeding errors of measurements increase of acceleration of free falling of the container at angular speed of rotation of a rotor up to 20 000 rev/min. The physical conditions of free vertical falling of a body essentially differ from conditions of rotary (orbital) movement of a body in the field of gravity and the result obtained by us does not contradict the results of measurements of a gyroscope precession on satellites. Experiments with dynamic weighing of bodies give useful information on complex properties of the gravity force which are beyond the scope of well-known theories. Their careful analysis will allow to expand and supplement the concepts based on the general theory of relativity, and probably to open a way to new physics of gravitation and to new principles of movement.

Stellar age spreads in clusters as imprints of cluster-parent clump densities

DOE Office of Scientific and Technical Information (OSTI.GOV)

Parmentier, G.; Grebel, E. K.; Pfalzner, S.

2014-08-20

It has recently been suggested that high-density star clusters have stellar age distributions much narrower than that of the Orion Nebula Cluster, indicating a possible trend of narrower age distributions for denser clusters. We show this effect to likely arise from star formation being faster in gas with a higher density. We model the star formation history of molecular clumps in equilibrium by associating a star formation efficiency per free-fall time, ε{sub ff}, to their volume density profile. We focus on the case of isothermal spheres and we obtain the evolution with time of their star formation rate. Our modelmore » predicts a steady decline of the star formation rate, which we quantify with its half-life time, namely, the time needed for the star formation rate to drop to half its initial value. Given the uncertainties affecting the star formation efficiency per free-fall time, we consider two distinct values: ε{sub ff} = 0.1 and ε{sub ff} = 0.01. When ε{sub ff} = 0.1, the half-life time is of the order of the clump free-fall time, τ{sub ff}. As a result, the age distributions of stars formed in high-density clumps have smaller full-widths at half-maximum than those of stars formed in low-density clumps. When the star formation efficiency per free-fall time is 0.01, the half-life time is 10 times longer, i.e., 10 clump free-fall times. We explore what happens if the duration of star formation is shorter than 10τ{sub ff}, that is, if the half-life time of the star formation rate cannot be defined. There, we build on the invariance of the shape of the young cluster mass function to show that an anti-correlation between the clump density and the duration of star formation is expected. We therefore conclude that, regardless of whether the duration of star formation is longer than the star formation rate half-life time, denser molecular clumps yield narrower star age distributions in clusters. Published densities and stellar age spreads of young clusters and star-forming regions actually suggest that the timescale for star formation is of order 1-4τ{sub ff}. We also discuss how the age bin size and uncertainties in stellar ages affect our results. We conclude that there is no need to invoke the existence of multiple cluster formation mechanisms to explain the observed range of stellar age spreads in clusters.« less

[INFLUENCE OF THE NUTRITIONAL COMPOSITION OF DIFFERENT FIBER-ENRICHED ENTERAL NUTRITION FORMULAS ON THE ADMINISTRATION TIME BY GRAVITY AND THE RISK OF TUBE FEEDING OBSTRUCTION].

PubMed

Bonada Sanjaume, Anna; Gils Contreras, Anna; Salas-Salvadó, Jordi

2015-08-01

the administration of enteral nutrition by gravity is a very useful method in clinical practice; nevertheless, it may not be very precise. Indeed, this method presents some important limitations, such as the difficulty in establishing a precise dripping rate and the possibility for the dripping rate decrease depending on the formula. assess the administration time and the risk of clogging of 5 fiber-enriched enteral nutrition formulas with different protein concentrations and caloric density, all administered by gravity through nasogastric (NG) tubes of different sizes. Assess the influence of the composition on the dripping rate, by gravity, of the tested formulas. 5 fiber-enriched EN formulas were compared by using nasogastric tubes of the calibers 8, 10 and 12 Fr. The fluidity of these gravity-administered NE formulas was estimated by timing the complete passage of each formula at full speed, thus allowing one to calculate the mean time of free fall (MTFF) and to register any possible obstruction. Subsequently, an in vitro simulation of a 1 500 ml administration was performed for each formula at a particular speed, so that the administration time was 5 hours. Slowing flow and stagnated flow were detected as indicators of the risk of obstruction. the two products that especially differed in MTFF were the ones with the highest energy concentration. The passage time in free fall of these two products through the 8 Fr tube exceeded four hours. For the rest of the products and NG tubes used, this time was less than 2 hours and 5 minutes. No slowing flow or tube obstruction was detected in free fall and at maximum speed. When the dripping was adjusted to be administered in 5 hours, three of the studied products (those with the least caloric concentration and viscosity) showed slowing flow and, in some cases, the dripping stopped completely. The most important factor associated to the MTFF was the lipid content, followed by viscosity, energy and protein content. The MTFF measured was not significantly related to the fiber content of the nutritional formula. all studied products can be administered by gravity via nasogastric tubes in free fall without any risk of obstruction, even though the free fall time was very variable. The lowest caliber tubes, the highest energy content and the viscosity of the EN mixture turn-out to be the limiting factors when fiber-enriched formulas are to be administered by gravity. Copyright AULA MEDICA EDICIONES 2014. Published by AULA MEDICA. All rights reserved.

[Assessment and training of strength and balance for fall prevention in the elderly: recommendations of an interdisciplinary expert panel].

PubMed

Granacher, U; Muehlbauer, T; Gschwind, Y J; Pfenninger, B; Kressig, R W

2014-08-01

The proportion of elderly people in societies of western industrialized countries is continuously rising. Biologic aging induces deficits in balance and muscle strength/power in old age, which is responsible for an increased prevalence of falls. Therefore, nationwide and easy-to-administer fall prevention programs have to be developed in order to contribute to the autonomy and quality of life in old age and to help reduce the financial burden on the public health care system due to the treatment of fall-related injuries. This narrative (qualitative) literature review deals with a) the reasons for an increased prevalence of falls in old age, b) important clinical tests for fall-risk assessment, and c) evidence-based intervention/training programs for fall prevention in old age. The findings of this literature review are based on a cost-free practice guide that is available to the public (via the internet) and that was created by an expert panel (i.e., geriatricians, exercise scientists, physiotherapists, geriatric therapists). The present review provides the scientific foundation of the practice guide.

The effect of physical restraints on fall rates in older adults who are institutionalized.

PubMed

Dunn, K S

2001-10-01

Since the Omnibus Budget Reconciliation Act (OBRA) of 1987, there has been a significant reduction in the use of physical restraints to prevent falls in older adults who are institutionalized because of the developing awareness of the physical and psychological problems associated with them. The purpose of this ex post facto descriptive study was to determine if there is a difference in falls when physical restraints are allowed or prohibited in one older adult population. Data from incident reports from a purposive sample of 97 older adults in one long-term care facility were analyzed before and after the implementation of a restraint-free policy. The results indicated no significant difference in the number of falls before and after the policy change. However, there was a significantly lower number of falls with injuries and a significantly higher number of falls without injuries. These findings suggest older adults will continue to fall with or without the use of physical restraints because of changes associated with the aging process and risk factors. Removing physical barriers from older adults and allowing freedom of movement may decrease the severity of injury sustained in a fall.

Group theoretical formulation of free fall and projectile motion

NASA Astrophysics Data System (ADS)

Düztaş, Koray

2018-07-01

In this work we formulate the group theoretical description of free fall and projectile motion. We show that the kinematic equations for constant acceleration form a one parameter group acting on a phase space. We define the group elements ϕ t by their action on the points in the phase space. We also generalize this approach to projectile motion. We evaluate the group orbits regarding their relations to the physical orbits of particles and unphysical solutions. We note that the group theoretical formulation does not apply to more general cases involving a time-dependent acceleration. This method improves our understanding of the constant acceleration problem with its global approach. It is especially beneficial for students who want to pursue a career in theoretical physics.

Near-field interferometry of a free-falling nanoparticle from a point-like source

NASA Astrophysics Data System (ADS)

Bateman, James; Nimmrichter, Stefan; Hornberger, Klaus; Ulbricht, Hendrik

2014-09-01

Matter-wave interferometry performed with massive objects elucidates their wave nature and thus tests the quantum superposition principle at large scales. Whereas standard quantum theory places no limit on particle size, alternative, yet untested theories—conceived to explain the apparent quantum to classical transition—forbid macroscopic superpositions. Here we propose an interferometer with a levitated, optically cooled and then free-falling silicon nanoparticle in the mass range of one million atomic mass units, delocalized over >150 nm. The scheme employs the near-field Talbot effect with a single standing-wave laser pulse as a phase grating. Our analysis, which accounts for all relevant sources of decoherence, indicates that this is a viable route towards macroscopic high-mass superpositions using available technology.

Bunch length compression method for free electron lasers to avoid parasitic compressions

DOEpatents

Douglas, David R.; Benson, Stephen; Nguyen, Dinh Cong; Tennant, Christopher; Wilson, Guy

2015-05-26

A method of bunch length compression method for a free electron laser (FEL) that avoids parasitic compressions by 1) applying acceleration on the falling portion of the RF waveform, 2) compressing using a positive momentum compaction (R.sub.56>0), and 3) compensating for aberration by using nonlinear magnets in the compressor beam line.

Do Objects of Different Weight Fall at the Same Time? Updating Naive Beliefs about Free-Falling Objects from Fictional and Informational Books in Young Children

ERIC Educational Resources Information Center

Venkadasalam, Vaunam P.; Ganea, Patricia A.

2018-01-01

This study examined whether children 4- and 5-years-old (N = 156) can revise a physical science misconception from different types of picture books. A realistic fiction book and informational book with identical images matched in word count and reading difficulty level were compared to a control book about plants. In the pretest and posttest,…

Green Team Hosts Plant Swap to Encourage Gardening | Poster

Cancer.gov

By Carolynne Keenan, Contributing Writer What started out as a way for Howard Young, Ph.D., to thin out his garden last fall turned into the NCI at Frederick Green Team’s Plant Swap. The group held its Fall Plant Swap on October 24, encouraging all members of the Fort Detrick community to pick up a free plant or swap a plant of theirs for another. “Those who love to garden

Changes in child exposure to environmental tobacco smoke (CHETS) study after implementation of smoke-free legislation in Scotland: national cross sectional survey.

PubMed

Akhtar, Patricia C; Currie, Dorothy B; Currie, Candace E; Haw, Sally J

2007-09-15

To detect any change in exposure to secondhand smoke among primary schoolchildren after implementation of smoke-free legislation in Scotland in March 2006. Comparison of nationally representative, cross sectional, class based surveys carried out in the same schools before and after legislation. Scotland. 2559 primary schoolchildren (primary 7; mean age 11.4 years) surveyed in January 2006 (before smoke-free legislation) and 2424 in January 2007 (after legislation). Salivary cotinine concentrations, reports of parental smoking, and exposure to tobacco smoke in public and private places before and after legislation. The geometric mean salivary cotinine concentration in non-smoking children fell from 0.36 (95% confidence interval 0.32 to 0.40) ng/ml to 0.22 (0.19 to 0.25) ng/ml after the introduction of smoke-free legislation in Scotland-a 39% reduction. The extent of the fall in cotinine concentration varied according to the number of parent figures in the home who smoked but was statistically significant only among pupils living in households in which neither parent figure smoked (51% fall, from 0.14 (0.13 to 0.16) ng/ml to 0.07 (0.06 to 0.08) ng/ml) and among pupils living in households in which only the father figure smoked (44% fall, from 0.57 (0.47 to 0.70) ng/ml to 0.32 (0.25 to 0.42) ng/ml). Little change occurred in reported exposure to secondhand smoke in pupils' own homes or in cars, but a small decrease in exposure in other people's homes was reported. Pupils reported lower exposure in cafes and restaurants and in public transport after legislation. The Scottish smoke-free legislation has reduced exposure to secondhand smoke among young people in Scotland, particularly among groups with lower exposure in the home. We found no evidence of increased secondhand smoke exposure in young people associated with displacement of parental smoking into the home. The Scottish smoke-free legislation has thus had a positive short term impact on young people's health, but further efforts are needed to promote both smoke-free homes and smoking cessation.

Flow Visualization and Pattern Formation in Vertically Falling Liquid Films

NASA Astrophysics Data System (ADS)

Balakotaiah, Vemuri; Malamataris, Nikolaos

2008-11-01

Analytical results of a low-dimensional two equation h-q model and results of a direct numerical simulation of the transient two-dimensional Navier Stokes equations are presented for vertically falling liquid films along a solid wall. The numerical study aims at the elucidation of the hydrodynamics of the falling film. The analytical study aims at the calculation of the parameter space where pattern formation occurs for this flow. It has been found that when the wave amplitude exceeds a certain magnitude, flow reversal occurs in the film underneath the minimum of the waves [1]. The instantaneous vortical structures possess two hyperbolic points on the vertical wall and an elliptic point in the film. As the wave amplitude increases further, the elliptic point reaches the free surface of the film and two more hyperbolic points are formed in the free surface that replace the elliptic point. Between the two hyperbolic points on the free surface, the streamwise component of velocity is negative and the film is divided into asymmetric patterns of up and down flows. Depending on the value of the Kapitza number, these patterns are either stationary or oscillatory. Physical reasons for the influence of the Kapitza number on pattern formation are given. Movies are shown where the pattern formation is demonstrated. [1] N.A.Malamataris and V.Balakotaiah (2008), AIChE J., 54(7), p. 1725-1740

The Design of Ocean Turbulence Measurement with a Free Fall Vertical Profiler

NASA Astrophysics Data System (ADS)

Luan, Xin; Xin, Jia; Zhu, Tieyi; Yang, Hua; Teng, Yuru; Song, Dalei

2018-03-01

The newly designed instrument Free Fall Vertical Profiler (FFVP) developed by Ocean University of China (OUC) had been deployed in the Western Pacific in March 08, 2017 and succeed to collect turbulence signals about 350-m-deep water. According to the requirements of turbulence measurement, the mechanical design was developed for turbulence platform to achieve stability and good flow tracking. By analysing the Heading, Pitch and Roll, the results suggested that the platform satisfies the requirements of stability. The power spectrum of the cleaned shear signals using the noise correction algorithm match well with the theoretical Nasmyth spectrum and the rate of turbulence dissipation are approximately 10-8 W/kg. In general, the FFVP was rationally designed and provided a good measurement platform for turbulence observation.

a Virtual Trip to the Schwarzschild-De Sitter Black Hole

NASA Astrophysics Data System (ADS)

Bakala, Pavel; Hledík, Stanislav; Stuchlík, Zdenĕk; Truparová, Kamila; Čermák, Petr

2008-09-01

We developed realistic fully general relativistic computer code for simulation of optical projection in a strong, spherically symmetric gravitational field. Standard theoretical analysis of optical projection for an observer in the vicinity of a Schwarzschild black hole is extended to black hole spacetimes with a repulsive cosmological constant, i.e, Schwarzschild-de Sitter (SdS) spacetimes. Influence of the cosmological constant is investigated for static observers and observers radially free-falling from static radius. Simulation includes effects of gravitational lensing, multiple images, Doppler and gravitational frequency shift, as well as the amplification of intensity. The code generates images of static observers sky and a movie simulations for radially free-falling observers. Techniques of parallel programming are applied to get high performance and fast run of the simulation code.

Free fall and harmonic oscillations: analyzing trampoline jumps

NASA Astrophysics Data System (ADS)

Pendrill, Ann-Marie; Eager, David

2015-01-01

Trampolines can be found in many gardens and also in some playgrounds. They offer an easily accessible vertical motion that includes free fall. In this work, the motion on a trampoline is modelled by assuming a linear relation between force and deflection, giving harmonic oscillations for small amplitudes. An expression for the cycle-time is obtained in terms of maximum normalized force from the trampoline and the harmonic frequency. A simple expression is obtained for the ratio between air-time and harmonic period, and the maximum g-factor. The results are compared to experimental results, including accelerometer data showing 7g during bounces on a small trampoline in an amusement park play area. Similar results are obtained on a larger garden trampoline, and even larger accelerations have been measured for gymnastic trampolines.

Accurate Fall Detection in a Top View Privacy Preserving Configuration.

PubMed

Ricciuti, Manola; Spinsante, Susanna; Gambi, Ennio

2018-05-29

Fall detection is one of the most investigated themes in the research on assistive solutions for aged people. In particular, a false-alarm-free discrimination between falls and non-falls is indispensable, especially to assist elderly people living alone. Current technological solutions designed to monitor several types of activities in indoor environments can guarantee absolute privacy to the people that decide to rely on them. Devices integrating RGB and depth cameras, such as the Microsoft Kinect, can ensure privacy and anonymity, since the depth information is considered to extract only meaningful information from video streams. In this paper, we propose an accurate fall detection method investigating the depth frames of the human body using a single device in a top-view configuration, with the subjects located under the device inside a room. Features extracted from depth frames train a classifier based on a binary support vector machine learning algorithm. The dataset includes 32 falls and 8 activities considered for comparison, for a total of 800 sequences performed by 20 adults. The system showed an accuracy of 98.6% and only one false positive.

Automatic segmentation of triaxial accelerometry signals for falls risk estimation.

PubMed

Redmond, Stephen J; Scalzi, Maria Elena; Narayanan, Michael R; Lord, Stephen R; Cerutti, Sergio; Lovell, Nigel H

2010-01-01

Falls-related injuries in the elderly population represent one of the most significant contributors to rising health care expense in developed countries. In recent years, falls detection technologies have become more common. However, very few have adopted a preferable falls prevention strategy through unsupervised monitoring in the free-living environment. The basis of the monitoring described herein was a self-administered directed-routine (DR) comprising three separate tests measured by way of a waist-mounted triaxial accelerometer. Using features extracted from the manually segmented signals, a reasonable estimate of falls risk can be achieved. We describe here a series of algorithms for automatically segmenting these recordings, enabling the use of the DR assessment in the unsupervised and home environments. The accelerometry signals, from 68 subjects performing the DR, were manually annotated by an observer. Using the proposed signal segmentation routines, an good agreement was observed between the manually annotated markers and the automatically estimated values. However, a decrease in the correlation with falls risk to 0.73 was observed using the automatic segmentation, compared to 0.81 when using markers manually placed by an observer.

Walking Distance as a Predictor of Falls in People With Multiple Sclerosis.

PubMed

Nilsagård, Ylva; Westerdahl, Elisabeth; Wittrin, Anna; Gunnarsson, Martin

2016-06-01

People with multiple sclerosis (PwMS) experience falls, usually when walking and transferring. The aim was to investigate if walking distance and patient overestimate of walking distance are predictors of falls in PwMS. A prospective study was conducted, with a single test occasion followed by prospective registration of falls for 3 months. All PwMS in Region Örebro County with a previously registered Expanded Disability Status Scale score between 3.0 and 7.0 in the Swedish MS Registry were invited to participate (n = 149). Altogether, data from 49 PwMS being relapse free for at least 3 months and with a confirmed Expanded Disability Status Scale between 1.5 and 7.0 upon study entry were analysed. Twenty-two PwMS (45%) fell during the study period, providing information of 66 falls. Walking distance or overestimate of one's walking distance, as compared with test results, did not predict falls in this MS sample. Walking and standing activities are associated with numerous falls in PwMS. Our data do not clearly support routine measurements of walking distance in assessing individual fall risk. © 2015 The Authors. Physiotherapy Research International published by John Wiley & Sons, Ltd. © 2015 The Authors. Physiotherapy Research International published by John Wiley & Sons, Ltd.

Annual Conference on Drug-Free Schools and Communities Proceedings (4th, Falls Church, Virginia, June 11-15, 1990).

ERIC Educational Resources Information Center

Office of Elementary and Secondary Education, Washington, DC. School Improvement Programs.

This publication summarizes the presentations at individual and group sessions of a conference called to facilitate a broad exchange of concepts and experiences among those individuals and organizations most closely involved with Drug-Free Schools and Communities Programs at the national, state, and local levels. It is intended to highlight key…

Introducing medlineplus.gov

MedlinePlus

... Bar Home Current Issue Past Issues Introducing medlineplus.gov Past Issues / Fall 2006 Table of Contents For ... Discover a world of FREE medical resources: medlineplus.gov Your gateway to the world's most comprehensive and ...

Results of Two Free-fall Experiments on Flutter of Thin Unswept Wings in the Transonic Speed Range

NASA Technical Reports Server (NTRS)

Lauten, William T , Jr; Nelson, Herbert C

1957-01-01

Results of four thin, unswept, flutter airfoils attached to two freely falling bodies are reported. Two airfoils fluttered at a Mach number of 0.85, a third airfoil fluttered at a Mach number of 1.03, and a fourth fluttered at a Mach number of 1.07. Results of calculations of flutter speed using incompressible and compressible air-force coefficients, including a Mach number of 1.0, are presented.

Whip use and race progress are associated with horse falls in hurdle and steeplechase racing in the UK.

PubMed

Pinchbeck, G L; Clegg, P D; Proudman, C J; Morgan, K L; French, N R

2004-07-01

Falls during racing present a risk of injury to both horse and jockey and a risk of fatality to horses. To use video recordings of races to describe the circumstances surrounding horse falls at hurdle and steeplechase fences and to identify and quantify within-race risk factors for horse falls in National Hunt racing in the UK. A retrospective, matched, nested case-control study using video recordings of races was conducted on 6 UK racecourses. Cases and controls were matched on both race type and jump number at which the fall occurred. Conditional logistic regression analysis was used to examine the univariable and multivariable relationship between predictor variables and the risk of falling. The risk of falling was significantly associated with whip use and race progress. Horses which were being whipped and progressing through the race were at greater than 7 times the risk of falling compared to horses which were not being whipped and which had no change in position or lost position through the field. This study has identified whip use and the position of the horse with respect to others in the field as potential risk factors for horse falls. If these findings are confirmed by the use of intervention trials (e.g. with whip-free or restricted whip use races), modifications could be introduced which would reduce the frequency of horse falls, leading to improved equine welfare.

Myoglobin translational diffusion in rat myocardium and its implication on intracellular oxygen transport.

PubMed

Lin, Ping-Chang; Kreutzer, Ulrike; Jue, Thomas

2007-01-15

Current theory of respiratory control invokes a role of myoglobin (Mb)-facilitated O2 diffusion in regulating the intracellular O2 flux, provided Mb diffusion can compete effectively with free O2 diffusion. Pulsed-field gradient NMR methods have now followed gradient-dependent changes in the distinct 1H NMR gamma CH3 Val E11 signal of MbO2 in perfused rat myocardium to obtain the endogenous Mb translational diffusion coefficient (D(Mb)) of 4.24 x 10(-7) cm2 s(-1) at 22 degrees C. The D(Mb) matches precisely the value predicted by in vivo NMR rotational diffusion measurements of Mb and shows no orientation preference. Given values in the literature for the Krogh's free O2 diffusion coefficient (K0), myocardial Mb concentration and a partial pressure of O2 that half saturates Mb (P50), the analysis yields an equipoise diffusion P(O2) of 1.77 mmHg, where Mb and free O2 contribute equally to the O2 flux. In the myocardium, Mb-facilitated O2 diffusion contributes increasingly more than free O2 diffusion when the P(O2) falls below 1.77 mmHg. In skeletal muscle, the P(O2) must fall below 5.72 mmHg. Altering the Mb P50 induces modest change. Mb-facilitated diffusion has a higher poise in skeletal muscle than in myocardium. Because the basal P(O2) hovers around 10 mmHg, Mb does not have a predominant role in facilitating O2 transport in myocardium but contributes significantly only when cellular oxygen falls below the equipoise diffusion P(O2).

Sphere forming method and apparatus

NASA Technical Reports Server (NTRS)

Youngberg, C. L.; Miller, C. G.; Stephens, J. B.; Finnerty, A. A. (Inventor)

1983-01-01

A system is provided for forming small accurately spherical objects. Preformed largely spherical objects are supported at the opening of a conduit on the update of hot gas emitted from the opening, so the object is in a molten state. The conduit is suddenly jerked away at a downward incline, to allow the molten object to drop in free fall, so that surface tension forms a precise sphere. The conduit portion that has the opening, lies in a moderate vacuum chamber, and the falling sphere passes through the chamber and through a briefly opened valve into a tall drop tower that contains a lower pressure, to allow the sphere to cool without deformation caused by falling through air.

Falling paper: Navier-Stokes solutions, model of fluid forces, and center of mass elevation.

PubMed

Pesavento, Umberto; Wang, Z Jane

2004-10-01

We investigate the problem of falling paper by solving the two dimensional Navier-Stokes equations subject to the motion of a free-falling body at Reynolds numbers around 10(3). The aerodynamic lift on a tumbling plate is found to be dominated by the product of linear and angular velocities rather than velocity squared, as appropriate for an airfoil. This coupling between translation and rotation provides a mechanism for a brief elevation of center of mass near the cusplike turning points. The Navier-Stokes solutions further provide the missing quantity in the classical theory of lift, the instantaneous circulation, and suggest a revised model for the fluid forces.

"Galileo Airborne Test Of Equivalence"-Gate

NASA Astrophysics Data System (ADS)

Nobili, A. M.; Unnikrishnan, C. S.; Suresh, D.

A differential Galileo-type mass dropping experiment named GAL was proposed at the University of Pisa in 1986 and completed at CERN in 1992 (Carusotto et al., PRL 69, 1722) in order to test the Equivalence Principle by testing the Universality of Free Fall. The free falling mass was a disk made of two half disks of different composition; a violation of equivalence would produce an angular acceleration of the disk around its symmetry axis, which was measured with a modified Michelson interferometer. GATE -``Galileo Airborne Test of Equivalence'' is a variant of that experiment to be performed in parabolic flight on-board the ``Airbus A300 Zero-g'' aircraft of the European Space Agency (ESA). The main advantages of GATE with respect to GAL are the longer time of free fall and the absence of weight in the final stage of unlocking. The longer time of fall makes the signal stronger (the signal grows quadratically with the time of fall); unlocking at zero-g can significantly reduce spurious angular accelerations of the disk due to inevitable imperfections in the locking/unlocking mechanism, which turned out to be the limiting factor in GAL. A preliminary estimate indicates that GATE should be able to achieve a sensitivity η ≡ Δ g/g≃ 10-13, an improvement by about 3 orders of magnitude with respect to GAL and by about 1 order of magnitude with respect to the best result obtained with a slowly rotating torsion balance by the ``Eöt-Wash'' group at the University of Washington. Ground tests of the read-out and of the locking/unlocking disturbances can be carried out prior to the aircraft experiment. Locking/unlocking tests, retrieval tests, as well as tests of the aircraft environment can be performed onboard the Airbus A-300 in preparation for the actual experiment. The GATE experiment can be viewed as an Equivalence Principle test of intermediate sensitivity between torsion balance ground tests (10-12), balloon or micro-satellite (150 kg) tests (GREAT and μ SCOPE: ≃ 10-15), small-satellite (300 kg) room temperature tests (GG: ≃ 10-17), large-satellite (1 ton) cryogenic tests (STEP: ≃ 10-18)

Method of evaporation

NASA Technical Reports Server (NTRS)

Dufresne, Eugene R.

1987-01-01

Liquids, such as juices, milk, molten metal and the like are concentrated by forming uniformly-sized, small droplets in a precision droplet forming assembly and deploying the droplets in free fall downwardly as a central column within an evacuated column with cool walls. A portion of the solvent evaporates. The vapor flows to the wall, condenses, and usually flows down the wall as a film to condensate collector and drain. The vertical column of freely falling droplets enters the splash guard. The condensate can be collected, sent to other towers or recycled.

Fall Detection in Individuals With Lower Limb Amputations Using Mobile Phones: Machine Learning Enhances Robustness for Real-World Applications.

PubMed

Shawen, Nicholas; Lonini, Luca; Mummidisetty, Chaithanya Krishna; Shparii, Ilona; Albert, Mark V; Kording, Konrad; Jayaraman, Arun

2017-10-11

Automatically detecting falls with mobile phones provides an opportunity for rapid response to injuries and better knowledge of what precipitated the fall and its consequences. This is beneficial for populations that are prone to falling, such as people with lower limb amputations. Prior studies have focused on fall detection in able-bodied individuals using data from a laboratory setting. Such approaches may provide a limited ability to detect falls in amputees and in real-world scenarios. The aim was to develop a classifier that uses data from able-bodied individuals to detect falls in individuals with a lower limb amputation, while they freely carry the mobile phone in different locations and during free-living. We obtained 861 simulated indoor and outdoor falls from 10 young control (non-amputee) individuals and 6 individuals with a lower limb amputation. In addition, we recorded a broad database of activities of daily living, including data from three participants' free-living routines. Sensor readings (accelerometer and gyroscope) from a mobile phone were recorded as participants freely carried it in three common locations-on the waist, in a pocket, and in the hand. A set of 40 features were computed from the sensors data and four classifiers were trained and combined through stacking to detect falls. We compared the performance of two population-specific models, trained and tested on either able-bodied or amputee participants, with that of a model trained on able-bodied participants and tested on amputees. A simple threshold-based classifier was used to benchmark our machine-learning classifier. The accuracy of fall detection in amputees for a model trained on control individuals (sensitivity: mean 0.989, 1.96*standard error of the mean [SEM] 0.017; specificity: mean 0.968, SEM 0.025) was not statistically different (P=.69) from that of a model trained on the amputee population (sensitivity: mean 0.984, SEM 0.016; specificity: mean 0.965, SEM 0.022). Detection of falls in control individuals yielded similar results (sensitivity: mean 0.979, SEM 0.022; specificity: mean 0.991, SEM 0.012). A mean 2.2 (SD 1.7) false alarms per day were obtained when evaluating the model (vs mean 122.1, SD 166.1 based on thresholds) on data recorded as participants carried the phone during their daily routine for two or more days. Machine-learning classifiers outperformed the threshold-based one (P<.001). A mobile phone-based fall detection model can use data from non-amputee individuals to detect falls in individuals walking with a prosthesis. We successfully detected falls when the mobile phone was carried across multiple locations and without a predetermined orientation. Furthermore, the number of false alarms yielded by the model over a longer period of time was reasonably low. This moves the application of mobile phone-based fall detection systems closer to a real-world use case scenario. ©Nicholas Shawen, Luca Lonini, Chaithanya Krishna Mummidisetty, Ilona Shparii, Mark V Albert, Konrad Kording, Arun Jayaraman. Originally published in JMIR Mhealth and Uhealth (http://mhealth.jmir.org), 11.10.2017.

Students' Decision Steps in Meta-Cognitive Learning in Free Online Groups (MetaL-FrOG): A Case Study

ERIC Educational Resources Information Center

Sen Fa, Kinsley Ng; Hussin, Firuz Hussin

2011-01-01

What prompts the students to respond in online dialogic discussion? Why some students chose to fall out? This case study through the lens of phenomenography observation attempts to explain the five decision steps of students to respond in Meta-cognitive Learning in Free Online Groups (MetaL-FrOG) discussion. It presents a part of a research…

Instructor Special Report: RIF (Reading Is FUNdamental)

ERIC Educational Resources Information Center

Instructor, 1976

1976-01-01

At a time when innovative programs of the sixties are quickly falling out of the picture, Reading Is FUNdamental, after ten years and five million free paperbacks, continues to expand and show results. (Editor)

DETAIL VIEW OF BRICK WALKWAY ON SOUTHEAST SIDE SHOWING NAMES ...

Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

DETAIL VIEW OF BRICK WALKWAY ON SOUTHEAST SIDE SHOWING NAMES OF DONORS TO RECENT RENOVATION - Free Library of Philadelphia, Falls of Schuylkill Branch, 3501 Midvale Avenue, Philadelphia, Philadelphia County, PA

Method and apparatus for supercooling and solidifying substances

NASA Technical Reports Server (NTRS)

Lacy, L. L.; Robinson, M. B.; Rathz, T. J.; Katz, L.; Nisen, D. B. (Inventor)

1983-01-01

An enclosure provides a containerless environment in which a sample specimen is positioned. The specimen is heated in the containerless environment, and the specimen melt is dropped through the tube in which it cools by radiation. The tube is alternatively backfilled with an inert gas whereby the specimen melt cools by both radiation and convection during its free fall. During the free fall, the sample is in a containerless, low-gravity environment which enhances supercooling in the sample and prevents sedimentation and thermal convection influences. The sample continues to supercool until nucleation occurs which is detected by silicon photovoltaic detectors. The sample solidifies after nucleation and becomes completely solid before entering the detachable catcher. The amount of supercooling of the specimen can be measured by knowing the cooling ratio and determining the time for nucleation to occur.

Reconstruction of Attitude Dynamics of Free Falling Units

NASA Astrophysics Data System (ADS)

Yuan, Y.; Ivchenko, N.; Tibert, G.; Schlatter, N. M.

2015-09-01

Attitude reconstruction of a free falling sphere for the experiment Multiple Spheres for Characterization of Atmosphere Temperatures (MUSCAT) is studied in this paper. The attitude dynamics is modeled through Euler's rotational equations of motion. To estimate uncertain parameters in this model such as the matrix of inertia and the lever arm for the dynamic pressure with respect to the center of mass, the dynamics reconstruction can be formulated as an optimization problem. The goal is to minimize the deviation between the measurements and the propagation from the system equations. This approach was tested against a couple of flight data sets which correspond to different periods of time. The result is very reasonable compared to the laboratory test. The estimate can be improved further through allowing drag coefficients variable and taking advantage of measurements from a magnetometer in numerical calculation.

Sub-Femto-g Free Fall for Space-Based Gravitational Wave Observatories: LISA Pathfinder Results.

PubMed

Armano, M; Audley, H; Auger, G; Baird, J T; Bassan, M; Binetruy, P; Born, M; Bortoluzzi, D; Brandt, N; Caleno, M; Carbone, L; Cavalleri, A; Cesarini, A; Ciani, G; Congedo, G; Cruise, A M; Danzmann, K; de Deus Silva, M; De Rosa, R; Diaz-Aguiló, M; Di Fiore, L; Diepholz, I; Dixon, G; Dolesi, R; Dunbar, N; Ferraioli, L; Ferroni, V; Fichter, W; Fitzsimons, E D; Flatscher, R; Freschi, M; García Marín, A F; García Marirrodriga, C; Gerndt, R; Gesa, L; Gibert, F; Giardini, D; Giusteri, R; Guzmán, F; Grado, A; Grimani, C; Grynagier, A; Grzymisch, J; Harrison, I; Heinzel, G; Hewitson, M; Hollington, D; Hoyland, D; Hueller, M; Inchauspé, H; Jennrich, O; Jetzer, P; Johann, U; Johlander, B; Karnesis, N; Kaune, B; Korsakova, N; Killow, C J; Lobo, J A; Lloro, I; Liu, L; López-Zaragoza, J P; Maarschalkerweerd, R; Mance, D; Martín, V; Martin-Polo, L; Martino, J; Martin-Porqueras, F; Madden, S; Mateos, I; McNamara, P W; Mendes, J; Mendes, L; Monsky, A; Nicolodi, D; Nofrarias, M; Paczkowski, S; Perreur-Lloyd, M; Petiteau, A; Pivato, P; Plagnol, E; Prat, P; Ragnit, U; Raïs, B; Ramos-Castro, J; Reiche, J; Robertson, D I; Rozemeijer, H; Rivas, F; Russano, G; Sanjuán, J; Sarra, P; Schleicher, A; Shaul, D; Slutsky, J; Sopuerta, C F; Stanga, R; Steier, F; Sumner, T; Texier, D; Thorpe, J I; Trenkel, C; Tröbs, M; Tu, H B; Vetrugno, D; Vitale, S; Wand, V; Wanner, G; Ward, H; Warren, C; Wass, P J; Wealthy, D; Weber, W J; Wissel, L; Wittchen, A; Zambotti, A; Zanoni, C; Ziegler, T; Zweifel, P

2016-06-10

We report the first results of the LISA Pathfinder in-flight experiment. The results demonstrate that two free-falling reference test masses, such as those needed for a space-based gravitational wave observatory like LISA, can be put in free fall with a relative acceleration noise with a square root of the power spectral density of 5.2±0.1  fm s^{-2}/sqrt[Hz], or (0.54±0.01)×10^{-15}  g/sqrt[Hz], with g the standard gravity, for frequencies between 0.7 and 20 mHz. This value is lower than the LISA Pathfinder requirement by more than a factor 5 and within a factor 1.25 of the requirement for the LISA mission, and is compatible with Brownian noise from viscous damping due to the residual gas surrounding the test masses. Above 60 mHz the acceleration noise is dominated by interferometer displacement readout noise at a level of (34.8±0.3)  fm/sqrt[Hz], about 2 orders of magnitude better than requirements. At f≤0.5  mHz we observe a low-frequency tail that stays below 12  fm s^{-2}/sqrt[Hz] down to 0.1 mHz. This performance would allow for a space-based gravitational wave observatory with a sensitivity close to what was originally foreseen for LISA.

Sub-Femto-g Free Fall for Space-Based Gravitational Wave Observatories: LISA Pathfinder Results

NASA Technical Reports Server (NTRS)

Armano, M.; Audley, H.; Auger, G.; Baird, J. T.; Bassan, M.; Binetruy, P.; Born, M.; Bortoluzzi, D.; Brandt, N.; Thorpe, J. I.

2016-01-01

We report the first results of the LISA Pathfinder in-flight experiment. The results demonstrate that two free-falling reference test masses, such as those needed for a space-based gravitational wave observatory like LISA, can be put in free fall with a relative acceleration noise with a square root of the power spectral density of 5.2 +/- 0.1 fm s(exp -2)/square root of Hz, or (0.54 +/- 0.01) x 10(exp -15) g/square root of Hz, with g the standard gravity, for frequencies between 0.7 and 20 mHz. This value is lower than the LISA Pathfinder requirement by more than a factor 5 and within a factor 1.25 of the requirement for the LISA mission, and is compatible with Brownian noise from viscous damping due to the residual gas surrounding the test masses. Above 60 mHz the acceleration noise is dominated by interferometer displacement readout noise at a level of (34.8 +/- 0.3) fm square root of Hz, about 2 orders of magnitude better than requirements. At f less than or equal to 0.5 mHz we observe a low-frequency tail that stays below 12 fm s(exp -2)/square root of Hz down to 0.1 mHz. This performance would allow for a space-based gravitational wave observatory with a sensitivity close to what was originally foreseen for LISA.

Passive control of a falling sphere by elliptic-shaped appendages

NASA Astrophysics Data System (ADS)

Lācis, Uǧis; Olivieri, Stefano; Mazzino, Andrea; Bagheri, Shervin

2017-03-01

The majority of investigations characterizing the motion of single or multiple particles in fluid flows consider canonical body shapes, such as spheres, cylinders, discs, etc. However, protrusions on bodies—either surface imperfections or appendages that serve a function—are ubiquitous in both nature and applications. In this work, we characterize how the dynamics of a sphere with an axis-symmetric wake is modified in the presence of thin three-dimensional elliptic-shaped protrusions. By investigating a wide range of three-dimensional appendages with different aspect ratios and lengths, we clearly show that the sphere with an appendage may robustly undergo an inverted-pendulum-like (IPL) instability. This means that the position of the appendage placed behind the sphere and aligned with the free-stream direction is unstable, similar to how an inverted pendulum is unstable under gravity. Due to this instability, nontrivial forces are generated on the body, leading to turn and drift, if the body is free to fall under gravity. Moreover, we identify the aspect ratio and length of the appendage that induces the largest side force on the sphere, and therefore also the largest drift for a freely falling body. Finally, we explain the physical mechanisms behind these observations in the context of the IPL instability, i.e., the balance between surface area of the appendage exposed to reversed flow in the wake and the surface area of the appendage exposed to fast free-stream flow.

Yarning about fall prevention: community consultation to discuss falls and appropriate approaches to fall prevention with older Aboriginal and Torres Strait Islander people.

PubMed

Lukaszyk, Caroline; Coombes, Julieann; Turner, Norma Jean; Hillmann, Elizabeth; Keay, Lisa; Tiedemann, Anne; Sherrington, Cathie; Ivers, Rebecca

2017-08-01

Fall related injury is an emerging issue for older Indigenous people worldwide, yet few targeted fall prevention programs are currently available for Indigenous populations. In order to inform the development of a new Aboriginal-specific fall prevention program in Australia, we conducted community consultation with older Aboriginal people to identify perceptions and beliefs about falls, and to identify desired program elements. Yarning Circles were held with Aboriginal and Torres Strait Islander people aged 45 years and over. Each Yarning Circle was facilitated by an Aboriginal researcher who incorporated six indicative questions into each discussion. Questions explored the impact of falls on Yarning Circle participants, their current use of fall prevention services and investigated Yarning Circle participant's preferences regarding the design and mode of delivery of a fall prevention program. A total of 76 older Aboriginal people participated in ten Yarning Circles across six sites in the state of New South Wales. Participants associated falls with physical disability, a loss of emotional well-being and loss of connection to family and community. Many participants did not use existing fall prevention services due to a lack of availability in their area, having no referral provided by their GP and/or being unaware of fall prevention programs in general. Program elements identified as important by participants were that it be Aboriginal-specific, group-based, and on-going, with the flexibility to be tailored to specific communities, with free transport provided to and from the program. Older Aboriginal people reported falls to be a priority health issue, with a significant impact on their health and well-being. Few older Aboriginal people accessed prevention programs, suggesting there is an important need for targeted Aboriginal-specific programs. A number of important program elements were identified which if incorporated into prevention programs, may help to address the rising burden of falls.

Executive function and falls in older adults: new findings from a five-year prospective study link fall risk to cognition.

PubMed

Mirelman, Anat; Herman, Talia; Brozgol, Marina; Dorfman, Moran; Sprecher, Elliot; Schweiger, Avraham; Giladi, Nir; Hausdorff, Jeffrey M

2012-01-01

Recent findings suggest that executive function (EF) plays a critical role in the regulation of gait in older adults, especially under complex and challenging conditions, and that EF deficits may, therefore, contribute to fall risk. The objective of this study was to evaluate if reduced EF is a risk factor for future falls over the course of 5 years of follow-up. Secondary objectives were to assess whether single and dual task walking abilities, an alternative window into EF, were associated with fall risk. We longitudinally followed 256 community-living older adults (age: 76.4±4.5 yrs; 61% women) who were dementia free and had good mobility upon entrance into the study. At baseline, a computerized cognitive battery generated an index of EF, attention, a closely related construct, and other cognitive domains. Gait was assessed during single and dual task conditions. Falls data were collected prospectively using monthly calendars. Negative binomial regression quantified risk ratios (RR). After adjusting for age, gender and the number of falls in the year prior to the study, only the EF index (RR: .85; CI: .74-.98, p = .021), the attention index (RR: .84; CI: .75-.94, p = .002) and dual tasking gait variability (RR: 1.11; CI: 1.01-1.23; p = .027) were associated with future fall risk. Other cognitive function measures were not related to falls. Survival analyses indicated that subjects with the lowest EF scores were more likely to fall sooner and more likely to experience multiple falls during the 66 months of follow-up (p<0.02). These findings demonstrate that among community-living older adults, the risk of future falls was predicted by performance on EF and attention tests conducted 5 years earlier. The present results link falls among older adults to cognition, indicating that screening EF will likely enhance fall risk assessment, and that treatment of EF may reduce fall risk.

Scale-free gravitational collapse as the origin of ρ ˜ r-2 density profile - a possible role of turbulence in regulating gravitational collapse

NASA Astrophysics Data System (ADS)

Li, Guang-Xing

2018-03-01

Astrophysical systems, such as clumps that form star clusters share a density profile that is close to ρ ˜ r-2. We prove analytically this density profile is the result of the scale-free nature of the gravitational collapse. Therefore, it should emerge in many different situations as long as gravity is dominating the evolution for a period that is comparable or longer than the free-fall time, and this does not necessarily imply an isothermal model, as many have previously believed. To describe the collapse process, we construct a model called the turbulence-regulated gravitational collapse model, where turbulence is sustained by accretion and dissipates in roughly a crossing time. We demonstrate that a ρ ˜ r-2 profile emerges due to the scale-free nature the system. In this particular case, the rate of gravitational collapse is regulated by the rate at which turbulence dissipates the kinetic energy such that the infall speed can be 20-50% of the free-fall speed(which also depends on the interpretation of the crossing time based on simulations of driven turbulence). These predictions are consistent with existing observations, which suggests that these clumps are in the stage of turbulence-regulated gravitational collapse. Our analysis provides a unified description of gravitational collapse in different environments.

Free fall and evaporation of N-Octane droplets in the atmosphere as applied to the jettisoning of aviation gasoline at altitude

NASA Technical Reports Server (NTRS)

Lowell, Herman H

1953-01-01

In connection with proposed rapid jettisoning of aviation gasoline at altitude, a theoretical study was made of the free fall and evaporation of N-octane droplets in the atmosphere ; N-octane was selected for study because of the expected similarity of over-all evaporation behavior of N-octane and gasoline. It was concluded that gasoline (or N-octane) droplets larger than 2000 microns in diameter would be unstable ; terminal speeds and Reynolds numbers were obtained for droplets not larger than 2000 microns at altitudes to 11,000 feet. The motion data were used in the calculation of N-octane evaporation rates under various conditions. It was found that a droplet having an original diameter of 2000 microns would fall about 4000 feet from 6000 feet under NACA standard atmosphere conditions before coming virtually to rest. Finally, it was concluded that temperature effects are of paramount importance; at highest air temperatures a 1000-foot ground clearance would probably be adequate to prevent ground contamination, whereas at lowest air temperatures only an atomizing spray arrangement would prevent ground contamination, irrespective of ground clearance.

Fall risks assessment among community dwelling elderly using wearable wireless sensors

NASA Astrophysics Data System (ADS)

Lockhart, Thurmon E.; Soangra, Rahul; Frames, Chris

2014-06-01

Postural stability characteristics are considered to be important in maintaining functional independence free of falls and healthy life style especially for the growing elderly population. This study focuses on developing tools of clinical value in fall prevention: 1) Implementation of sensors that are minimally obtrusive and reliably record movement data. 2) Unobtrusively gather data from wearable sensors from four community centers 3) developed and implemented linear and non-linear signal analysis algorithms to extract clinically relevant information using wearable technology. In all a total of 100 community dwelling elderly individuals (66 non-fallers and 34 fallers) participated in the experiment. All participants were asked to stand-still in eyes open (EO) and eyes closed (EC) condition on forceplate with one wireless inertial sensor affixed at sternum level. Participants' history of falls had been recorded for last 2 years, with emphasis on frequency and characteristics of falls. Any participant with at least one fall in the prior year were classified as faller and the others as non-faller. The results indicated several key factors/features of postural characteristics relevant to balance control and stability during quite stance and, showed good predictive capability of fall risks among older adults. Wearable technology allowed us to gather data where it matters the most to answer fall related questions, i.e. the community setting environments. This study opens new prospects of clinical testing using postural variables with a wearable sensor that may be relevant for assessing fall risks at home and patient environment in near future.

Community Delivery of a Comprehensive Fall-Prevention Program in People with Multiple Sclerosis

PubMed Central

Frankel, Debra; Tompkins, Sara A.; Cameron, Michelle

2016-01-01

Background: People with multiple sclerosis (MS) fall frequently. In 2011, the National Multiple Sclerosis Society launched a multifactorial fall-prevention group exercise and education program, Free From Falls (FFF), to prevent falls in MS. The objective of this study was to assess the impact of participation in the FFF program on balance, mobility, and falls in people with MS. Methods: This was a retrospective evaluation of assessments from community delivery of FFF. Changes in Activities-specific Balance Confidence scale scores, Berg Balance Scale scores, 8-foot Timed Up and Go performance, and falls were assessed. Results: A total of 134 participants completed the measures at the first and last FFF sessions, and 109 completed a 6-month follow-up assessment. Group mean scores on the Activities-specific Balance Confidence scale (F1,66 = 17.14, P < .05, η2 = 0.21), Berg Balance Scale (F1,68 = 23.39, P < .05, η2 = 0.26), and 8-foot Timed Up and Go (F1,79 = 4.83, P < .05, η2 = 0.06) all improved significantly from the first to the last session. At the 6-month follow-up, fewer falls were reported (χ2 [4, N = 239] = 10.56, P < .05, Phi = 0.21). Conclusions: These observational data suggest that the FFF group education and exercise program improves balance confidence, balance performance, and functional mobility and reduces falls in people with MS. PMID:26917997

Parachuting with bristled wings

NASA Astrophysics Data System (ADS)

Kasoju, Vishwa; Santhanakrishnan, Arvind; Senter, Michael; Armel, Kristen; Miller, Laura

2017-11-01

Free takeoff flight recordings of thrips (body length <1 mm) show that they can intermittently cease flapping and instead float passively downwards by spreading their bristled wings. Such drag-based parachuting can lower the speed of falling and aid in long distance dispersal by minimizing energetic demands needed for active flapping flight. However, the role of bristled wings in parachuting remains unclear. In this study, we examine if using bristled wings lowers drag forces in parachuting as compared to solid (non-bristled) wings. Wing angles and settling velocities were obtained from free takeoff flight videos. A solid wing model and bristled wing model with bristle spacing to diameter ratio of 5 performing translational motion were comparatively examined using a dynamically scaled robotic model. We measured force generated under varying wing angle from 45-75 degrees across a Reynolds number (Re) range of 1 to 15. Drag experienced by the wings decreased in both wing models when varying Re from 1 to 15. Leakiness of flow through bristles, visualized using spanwise PIV, and implications for force generation will be presented. Numerical simulations will be used to investigate the stability of free fall using bristled wings.

The role of geriatric assessment tests and anthropometric measurements in identifying the risk of falls in elderly nursing home residents

PubMed Central

Yardimci, Bulent; Aran, Sinan N.; Ozkaya, Ismail; Aksoy, Sevki M.; Demir, Tarik; Tezcan, Gulsen; Kaptanoglu, Aysegul Y.

2016-01-01

Objectives: To determine the relation among the risk of falls, geriatric assessment, and anthropometric measurements, including the mini mental state examination, geriatric depression scale, handgrip test, and key pinch test. Methods: This prospective study included 89 residents hospitalized between May 2014 and September 2015 in the geriatric care unit of the Istanbul Balikli Rum Hospital, Istanbul, Turkey. Patients were followed-up for one year, and their falls were recorded. Medical records of the included patients were retrieved and analyzed. Results: A total of 89 patients, comprising 37 men and 52 women with an average age of 75.8 ± 8.2 years were included in the study. The residents’ annual falling averages were 1.0 ± 1.5. The most significant factors were identified to be predicted muscle mass, skeletal muscle index, whole body bioimpedance, dominant arm muscle strength, dominant arm bioimpedance, and free fat mass. Conclusions: The mini mental test, geriatric depression scale and lawton-brody scale combined with the handgrip, 6-meters walking, and bioimpedance tests are favorable for detecting the risk of falls and recurrent falls in vulnerable elderly nursing home residents. PMID:27652361

Changes in child exposure to environmental tobacco smoke (CHETS) study after implementation of smoke-free legislation in Scotland: national cross sectional survey

PubMed Central

Currie, Dorothy B; Currie, Candace E; Haw, Sally J

2007-01-01

Objective To detect any change in exposure to secondhand smoke among primary schoolchildren after implementation of smoke-free legislation in Scotland in March 2006. Design Comparison of nationally representative, cross sectional, class based surveys carried out in the same schools before and after legislation. Setting Scotland. Participants 2559 primary schoolchildren (primary 7; mean age 11.4 years) surveyed in January 2006 (before smoke-free legislation) and 2424 in January 2007 (after legislation). Outcome measures Salivary cotinine concentrations, reports of parental smoking, and exposure to tobacco smoke in public and private places before and after legislation. Results The geometric mean salivary cotinine concentration in non-smoking children fell from 0.36 (95% confidence interval 0.32 to 0.40) ng/ml to 0.22 (0.19 to 0.25) ng/ml after the introduction of smoke-free legislation in Scotland—a 39% reduction. The extent of the fall in cotinine concentration varied according to the number of parent figures in the home who smoked but was statistically significant only among pupils living in households in which neither parent figure smoked (51% fall, from 0.14 (0.13 to 0.16) ng/ml to 0.07 (0.06 to 0.08) ng/ml) and among pupils living in households in which only the father figure smoked (44% fall, from 0.57 (0.47 to 0.70) ng/ml to 0.32 (0.25 to 0.42) ng/ml). Little change occurred in reported exposure to secondhand smoke in pupils' own homes or in cars, but a small decrease in exposure in other people's homes was reported. Pupils reported lower exposure in cafes and restaurants and in public transport after legislation. Conclusions The Scottish smoke-free legislation has reduced exposure to secondhand smoke among young people in Scotland, particularly among groups with lower exposure in the home. We found no evidence of increased secondhand smoke exposure in young people associated with displacement of parental smoking into the home. The Scottish smoke-free legislation has thus had a positive short term impact on young people's health, but further efforts are needed to promote both smoke-free homes and smoking cessation. PMID:17827487

Impact-induced acceleration by obstacles

NASA Astrophysics Data System (ADS)

Corbin, N. A.; Hanna, J. A.; Royston, W. R.; Singh, H.; Warner, R. B.

2018-05-01

We explore a surprising phenomenon in which an obstruction accelerates, rather than decelerates, a moving flexible object. It has been claimed that the right kind of discrete chain falling onto a table falls faster than a free-falling body. We confirm and quantify this effect, reveal its complicated dependence on angle of incidence, and identify multiple operative mechanisms. Prior theories for direct impact onto flat surfaces, which involve a single constitutive parameter, match our data well if we account for a characteristic delay length that must impinge before the onset of excess acceleration. Our measurements provide a robust determination of this parameter. This supports the possibility of modeling such discrete structures as continuous bodies with a complicated constitutive law of impact that includes angle of incidence as an input.

A Person Stands on a Balance in an Elevator: What Happens When the Elevator Starts to Fall?

NASA Astrophysics Data System (ADS)

Baluković, Jasmina; Slisko, Josip; Cruz, Adrián Corona

2018-03-01

Physics textbook authors commonly introduce the concept of weightlessness (apparent or real) through a "thought experiment" in which a person weighs herself or himself in an elevator. When the elevator falls freely, the spring balance should show zero weight. There is an unresolved controversy about how this "zero reading" comes about. Drawings in some books, the first of which appeared in a book of Perelman 80 years ago, show that the person continues to be in contact with the balance. It means that "zero weight" arises as a consequence of "the fact" that the falling person and balance, although in contact, don't press on each other. Drawings in other books, among them those elaborated by NASA, represent the person and the balance launched upward and floating separately in midair. Using a homemade "falling box" with attached video camera, we did initial experiments for a very simplified but basically similar situation. The results that we obtained suggest that, in a free-falling elevator, a real balance would hardly launch a person upward.

Free-Fall Sex and Golden Eggs

ERIC Educational Resources Information Center

Burke, Michael C.

1978-01-01

Provides an annotated bibliography of science fiction literature suitable for use with secondary school students. Connections between science fiction and the science disciplines are viewed by the author as an excellent method by which to enrich science classes. (CP)

National Children's Center for Rural and Agricultural Health and Safety

MedlinePlus

... Network Grain Safety Model Policy: Youth Employment in Agriculture Agricultural Youth Work Guidelines North American Guidelines for ... Sept. 20 Teaching fall and electrical safety in agriculture: free webinar, Sept. 13 Agricultural Youth Work Guidelines ...

46 CFR 199.175 - Survival craft and rescue boat equipment.

Code of Federal Regulations, 2011 CFR

2011-10-01

... and must provide at least 10,000 kiloJoules (2,390 calories). Individual provision packages may... hatchet counts towards this requirement in rigid rescue boats. 5 Oars are not required on a free-fall...

Approaching Free Fall on Two Degrees of Freedom: Simultaneous Measurement of Residual Force and Torque on a Double Torsion Pendulum.

PubMed

Bassan, M; Cavalleri, A; De Laurentis, M; De Marchi, F; De Rosa, R; Di Fiore, L; Dolesi, R; Finetti, N; Garufi, F; Grado, A; Hueller, M; Marconi, L; Milano, L; Pucacco, G; Stanga, R; Visco, M; Vitale, S; Weber, W J

2016-02-05

A torsion pendulum with 2 soft degrees of freedom (DOFs), realized by off-axis cascading two torsion fibers, has been built and operated. This instrument helps characterize the geodesic motion of a test mass for LISA Pathfinder or any other free-fall space mission, providing information on cross talk and other effects that cannot be detected when monitoring a single DOF. We show that it is possible to simultaneously measure both the residual force and the residual torque acting on a quasifree test mass. As an example of the investigations that a double pendulum allows, we report the measurement of the force-to-torque cross talk, i.e., the amount of actuation signal, produced by applying a force on the suspended test mass, that leaks into the rotational DOF, detected by measuring the corresponding (unwanted) torque.

Filament wound data base development, revision 1

NASA Technical Reports Server (NTRS)

Sharp, R. Scott; Braddock, William F.

1985-01-01

The objective was to update the present Space Shuttle Solid Rocket Booster (SRB) baseline reentry aerodynamic data base and to develop a new reentry data base for the filament wound case SRB along with individual protuberance increments. Lockheed's procedures for performing these tasks are discussed. Free fall of the SRBs after separation from the Space Shuttle Launch Vehicle is completely uncontrolled. However, the SRBs must decelerate to a velocity and attitude that is suitable for parachute deployment. To determine the SRB reentry trajectory parameters, including the rate of deceleration and attitude history during free-fall, engineers at Marshall Space Flight Center are using a six-degree-of-freedom computer program to predict dynamic behavior. Static stability aerodynamic coefficients are part of the information required for input into this computer program. Lockheed analyzed the existing reentry aerodynamic data tape (Data Tape 5) for the current steel case SRB. This analysis resulted in the development of Data Tape 7.

A probabilistic approach for mine burial prediction

NASA Astrophysics Data System (ADS)

Barbu, Costin; Valent, Philip; Richardson, Michael; Abelev, Andrei; Plant, Nathaniel

2004-09-01

Predicting the degree of burial of mines in soft sediments is one of the main concerns of Naval Mine CounterMeasures (MCM) operations. This is a difficult problem to solve due to uncertainties and variability of the sediment parameters (i.e., density and shear strength) and of the mine state at contact with the seafloor (i.e., vertical and horizontal velocity, angular rotation rate, and pitch angle at the mudline). A stochastic approach is proposed in this paper to better incorporate the dynamic nature of free-falling cylindrical mines in the modeling of impact burial. The orientation, trajectory and velocity of cylindrical mines, after about 4 meters free-fall in the water column, are very strongly influenced by boundary layer effects causing quite chaotic behavior. The model's convolution of the uncertainty through its nonlinearity is addressed by employing Monte Carlo simulations. Finally a risk analysis based on the probability of encountering an undetectable mine is performed.

A comparison of acoustic levitation with microgravity processing for containerless solidification of ternary Al-Cu-Sn alloy

NASA Astrophysics Data System (ADS)

Yan, N.; Hong, Z. Y.; Geng, D. L.; Wei, B.

2015-07-01

The containerless rapid solidification of liquid ternary Al-5 %Cu-65 %Sn immiscible alloy was accomplished at both ultrasonic levitation and free fall conditions. A maximum undercooling of 185 K (0.22 T L) was obtained for the ultrasonically levitated alloy melt at a cooling rate of about 122 K s-1. Meanwhile, the cooling rate of alloy droplets in drop tube varied from 102 to 104 K s-1. The macrosegregation was effectively suppressed through the complex melt flow under ultrasonic levitation condition. In contrast, macrosegregation became conspicuous and core-shell structures with different layers were formed during free fall. The microstructure formation mechanisms during rapid solidification at containerless states were investigated in comparison with the conventional static solidification process. It was found that the liquid phase separation and structural growth kinetics may be modulated by controlling both alloy undercooling and cooling rate.

Generalized mathematical model of red muds’ thickener of alumina production

NASA Astrophysics Data System (ADS)

Fedorova, E. R.; Vinogradova, A. A.

2018-03-01

The article describes the principle of a generalized mathematical model of the red mud’s thickener construction. The model of the red muds’ thickener of alumina production consists of sub-models of flocculation zones containing solid fraction feed slurry, free-fall and cramped sedimentation zones or effective sedimentation zones, bleaching zones. The generalized mathematical model of thickener allows predicting the content of solid fraction in the condensed product and in the upper discharge. The sub-model of solid phase aggregation allows one to count up average size of floccules, which is created during the flocculation process in feedwell. The sub-model of the free-fall and cramped sedimentation zone allows one to count up the concentration profile taking into account the variable cross-sectional area of the thickener. The sub-model of the bleaching zone is constructed on the basis of the theory of the precipitation of Kinc, supplemented by correction factors.

Aerodynamics of a highly irregular body at transonic speeds-Analysis of STRATOS flight data.

PubMed

Guerster, Markus; Walter, Ulrich

2017-01-01

In this paper, we analyze the trajectory and body attitude data of Felix Baumgartner's supersonic free fall through the atmosphere on October 14, 2012. As one of us (UW) was scientific advisor to the Red Bull Stratos team, the analysis is based on true body data (body mass, wetted pressure suit surface area) and actual atmospheric data from weather balloon measurements. We also present a fully developed theoretical analysis and solution of atmospheric free fall. By matching the flight data against this solution, we are able to derive and track the drag coefficient CD from the subsonic to the transonic and supersonic regime, and back again. Although the subsonic drag coefficient is the expected CD = 0.60 ± 0.05, surprisingly the transonic compressibility drag coefficient is only 19% of the expected value. We provide a plausible explanation for this unexpected result.

Convection in an ideal gas at high Rayleigh numbers.

PubMed

Tilgner, A

2011-08-01

Numerical simulations of convection in a layer filled with ideal gas are presented. The control parameters are chosen such that there is a significant variation of density of the gas in going from the bottom to the top of the layer. The relations between the Rayleigh, Peclet, and Nusselt numbers depend on the density stratification. It is proposed to use a data reduction which accounts for the variable density by introducing into the scaling laws an effective density. The relevant density is the geometric mean of the maximum and minimum densities in the layer. A good fit to the data is then obtained with power laws with the same exponent as for fluids in the Boussinesq limit. Two relations connect the top and bottom boundary layers: The kinetic energy densities computed from free fall velocities are equal at the top and bottom, and the products of free fall velocities and maximum horizontal velocities are equal for both boundaries.

Aerodynamics of a highly irregular body at transonic speeds—Analysis of STRATOS flight data

PubMed Central

Guerster, Markus; Walter, Ulrich

2017-01-01

In this paper, we analyze the trajectory and body attitude data of Felix Baumgartner’s supersonic free fall through the atmosphere on October 14, 2012. As one of us (UW) was scientific advisor to the Red Bull Stratos team, the analysis is based on true body data (body mass, wetted pressure suit surface area) and actual atmospheric data from weather balloon measurements. We also present a fully developed theoretical analysis and solution of atmospheric free fall. By matching the flight data against this solution, we are able to derive and track the drag coefficient CD from the subsonic to the transonic and supersonic regime, and back again. Although the subsonic drag coefficient is the expected CD = 0.60 ± 0.05, surprisingly the transonic compressibility drag coefficient is only 19% of the expected value. We provide a plausible explanation for this unexpected result. PMID:29216204

The Study of Leukocyte Functions in a Rotating Wall Vessel

NASA Technical Reports Server (NTRS)

Trial, JoAnn

1998-01-01

The objective of this study was to investigate the behavior of leukocytes under free-fall conditions in a rotating wall vessel. In such a vessel, the tendency of a cell to fall in response to gravity is opposed by the rotation of the vessel and the culture medium within, keeping the cells in suspension without fluid shear. Previous reports indicated that such functions as lymphocyte migration through collagen matrix or monocyte cytokine secretion are altered under these conditions, and these changes correlate with similar functional defects of cultured cells seen during spaceflight.

Marine Physics: Internal-Surface Wave Interaction and Microstructure Measurement Program

DTIC Science & Technology

1974-12-31

Stabilized Free-Fall Vehicles" 2. "On the Decay of Grid Generated Turbulence in Stratified Salt Water" Figure 1 Figure 2 Figure 3 Figure 4 Page 6 6...Ju.IJic.l modelling shows this vehicle to be stable ^h^iting tilts of less than 10-2 radians under fall into VTra e u Lving at 20 cm/sec. For...Fim^vm scaled according to an overall Froude number U/LN, scaling the vertical wake width, where U is the grid speed, L the mesh size of the grid

Star Formation in Massive Clusters via Bondi Accretion

NASA Astrophysics Data System (ADS)

Murray, Norman; Chang, Philip

2012-02-01

Essentially all stars form in giant molecular clouds (GMCs). However, inside GMCs, most of the gas does not participate in star formation; rather, denser gas accumulates in clumps in the GMC, with the bulk of the stars in a given GMC forming in a few of the most massive clumps. In the Milky Way, these clumps have masses M cl <~ 5 × 10-2 of the GMC, radii r cl ~ 1 pc, and free-fall times τcl ~ 2 × 105 yr. We show that clumps inside GMCs should accrete at a modified Bondi accretion rate, which depends on clump mass as \\dot{M}_{cl}\\sim M_{cl}^{5/4}. This rate is initially rather slow, usually slower than the initial star formation rate inside the clump (we adopt the common assumption that inside the clump, \\dot{M}_*=\\epsilon _ffM_{cl}/\\tau _{cl}, with epsilonff ≈ 0.017). However, after ~2 GMC free-fall times τGMC, the clump accretion rate accelerates rapidly; formally, the clump can accrete the entire GMC in ~3τGMC. At the same time, the star formation rate accelerates, tracking the Bondi accretion rate. If the GMC is disrupted by feedback from the largest clump, half the stars in that clump form in the final τGMC before the GMC is disrupted. The theory predicts that the distribution of effective star formation rates, measured per GMC free-fall time, is broad, ranging from ~0.001 up to 0.1 or larger and that the mass spectrum of star clusters is flatter than that of clumps, consistent with observations.

Progressive Adaptive Physical Activity in Stroke Improves Balance, Gait, and Fitness: Preliminary Results

PubMed Central

Michael, Kathleen; Goldberg, Andrew P.; Treuth, Margarita S.; Beans, Jeffrey; Normandt, Peter; Macko, Richard F.

2010-01-01

Purpose We conducted a noncontrolled pilot intervention study in stroke survivors to examine the efficacy of low-intensity adaptive physical activity to increase balance, improve walking function, and increase cardiovascular fitness and to determine whether improvements were carried over into activity profiles in home and community. Method Adaptive physical activity sessions were conducted 3 times/week for 6 months. The main outcomes were Berg Balance Scale, Dynamic Gait Index, 6-Minute Walk Test, cardiovascular fitness (VO2 peak), Falls Efficacy Scale, and 5-day Step Activity Monitoring. Results Seven men and women with chronic ischemic stroke completed the 6-month intervention. The mean Berg Balance baseline score increased from 33.9 ± 8.5 to 46 ± 6.7 at 6 months (mean ± SD; p = .006). Dynamic Gait Index increased from 13.7 ± 3.0 to 19.0 ± 3.5 (p = .01). Six-minute walk distance increased from 840 ± 110 feet to 935 ± 101 feet (p = 0.02). VO2 peak increased from 15.3 ± 4.1 mL/kg/min to 17.5 ± 4.7 mL/kg/min (p = .03). There were no significant changes in falls efficacy or free-living ambulatory activity. Conclusion A structured adaptive physical activity produces improvements in balance, gait, fitness, and ambulatory performance but not in falls efficacy or free-living daily step activity. Randomized studies are needed to determine the cardiovascular health and functional benefits of structured group physical activity programs and to develop behavioral interventions that promote increased free-living physical activity patterns. PMID:19581199

Non-linear quantization error reduction for the temperature measurement subsystem on-board LISA Pathfinder

NASA Astrophysics Data System (ADS)

Sanjuan, J.; Nofrarias, M.

2018-04-01

Laser Interferometer Space Antenna (LISA) Pathfinder is a mission to test the technology enabling gravitational wave detection in space and to demonstrate that sub-femto-g free fall levels are possible. To do so, the distance between two free falling test masses is measured to unprecedented sensitivity by means of laser interferometry. Temperature fluctuations are one of the noise sources limiting the free fall accuracy and the interferometer performance and need to be known at the ˜10 μK Hz-1/2 level in the sub-millihertz frequency range in order to validate the noise models for the future space-based gravitational wave detector LISA. The temperature measurement subsystem on LISA Pathfinder is in charge of monitoring the thermal environment at key locations with noise levels of 7.5 μK Hz-1/2 at the sub-millihertz. However, its performance worsens by one to two orders of magnitude when slowly changing temperatures are measured due to errors introduced by analog-to-digital converter non-linearities. In this paper, we present a method to reduce this effect by data post-processing. The method is applied to experimental data available from on-ground validation tests to demonstrate its performance and the potential benefit for in-flight data. The analog-to-digital converter effects are reduced by a factor between three and six in the frequencies where the errors play an important role. An average 2.7 fold noise reduction is demonstrated in the 0.3 mHz-2 mHz band.

Experimental evaluation of the drag coefficient for smooth spheres by free fall experiments in old mines

NASA Astrophysics Data System (ADS)

Maroto, J. A.; Dueñas-Molina, J.; de Dios, J.

2005-05-01

Mines of Linares, Jaén, Spain, have been exploited from the age of the Phoenicians, Carthaginians and Romans. These silver and lead mines reached their maximum splendour at the end of the 19th century and at the beginning of the 20th century. Nevertheless, all the mining works finished in the 1970s and the diverse machinery was sold. Only the shafts remain since then which has now permitted carrying out interesting free fall experiments using smooth spheres of both cork and cast iron. The experiments were facilitated by the fact that the tubular shape of the shafts provides excellent transmission of sound, which made feasible the recording of the impact sound of the spheres with water at the bottom of the shafts at distances of up to 200 m. By using these experimental data, we have carried out an evaluation of the drag coefficient for the movement of smooth spheres through the air in the laminar regime with Reynolds number in the interval 103 to 2 × 105. This evaluation was in excellent agreement with the literature data. From the theoretical point of view, the analysis of the free fall movement includes a variety of concepts such as Newton's second law, the drag force, Archimedes principle and the velocity of sound, which makes these experiments very attractive for both physics teachers and physics students at university level. Finally, an easy experiment is proposed in this paper which has permitted an approximate evaluation of the drag coefficient for smooth spheres to be carried out in a laboratory environment.

Non-linear quantization error reduction for the temperature measurement subsystem on-board LISA Pathfinder.

PubMed

Sanjuan, J; Nofrarias, M

2018-04-01

Laser Interferometer Space Antenna (LISA) Pathfinder is a mission to test the technology enabling gravitational wave detection in space and to demonstrate that sub-femto-g free fall levels are possible. To do so, the distance between two free falling test masses is measured to unprecedented sensitivity by means of laser interferometry. Temperature fluctuations are one of the noise sources limiting the free fall accuracy and the interferometer performance and need to be known at the ∼10 μK Hz -1/2 level in the sub-millihertz frequency range in order to validate the noise models for the future space-based gravitational wave detector LISA. The temperature measurement subsystem on LISA Pathfinder is in charge of monitoring the thermal environment at key locations with noise levels of 7.5 μK Hz -1/2 at the sub-millihertz. However, its performance worsens by one to two orders of magnitude when slowly changing temperatures are measured due to errors introduced by analog-to-digital converter non-linearities. In this paper, we present a method to reduce this effect by data post-processing. The method is applied to experimental data available from on-ground validation tests to demonstrate its performance and the potential benefit for in-flight data. The analog-to-digital converter effects are reduced by a factor between three and six in the frequencies where the errors play an important role. An average 2.7 fold noise reduction is demonstrated in the 0.3 mHz-2 mHz band.

Assessing the Quality of a Nonrandomized Pragmatic Trial for Primary Prevention of Falls among Older Adults

PubMed Central

Albert, Steven M.; Edelstein, Offer; King, Jennifer; Flatt, Jason; Lin, Chyongchiou J.; Boudreau, Robert; Newman, Anne B.

2014-01-01

Background Current approaches to falls prevention mostly rely on secondary and tertiary prevention and target individuals at high risk of falls. An alternative is primary prevention, in which all seniors are screened, referred as appropriate, and educated regarding falls risk. Little information is available on research designs that allow investigation of this approach in the setting of aging services delivery, where randomization may not be possible. Methods Healthy Steps for Older Adults, a statewide program of the Pennsylvania (PA) Department of Aging, involves a combination of education about falls and screening for balance problems, with referral to personal physicians and home safety assessments. We developed a nonrandomized statewide trial, Falls Free PA, to assess its effectiveness in reducing falls incidence over 12 months. We recruited 814 seniors who completed the program (503 first time participants, 311 people repeating the program) and 1020 who did not participate in the program, from the same sites. We assessed the quality of this nonrandomized design by examining recruitment, follow-up across study groups, and comparability at baseline. Results Of older adults approached in senior centers, 90.5% (n=2219) signed informed consent, and 1834 (82.4%) completed baseline assessments and were eligible for follow-up. Attrition in the three groups over 12 months was low and non-differential (<10% for withdrawal and <2% for other loss to follow-up). Median follow-up, which involved standardized monthly assessment of falls, was 10 months in all study groups. At baseline the groups did not differ in measures of health or falls risk factors. Conclusions Comparable status at baseline, recruitment from common sites, and similar experience with retention suggest that the nonrandomized design will be effective for assessment of this approach to primary prevention of falls. PMID:24488533

Assessing the quality of a non-randomized pragmatic trial for primary prevention of falls among older adults.

PubMed

Albert, Steven M; Edelstein, Offer; King, Jennifer; Flatt, Jason; Lin, Chyongchiou J; Boudreau, Robert; Newman, Anne B

2015-01-01

Current approaches to falls prevention mostly rely on secondary and tertiary prevention and target individuals at high risk of falls. An alternative is primary prevention, in which all seniors are screened, referred as appropriate, and educated regarding falls risk. Little information is available on research designs that allow investigation of this approach in the setting of aging services delivery, where randomization may not be possible. Healthy Steps for Older Adults, a statewide program of the Pennsylvania (PA) Department of Aging, involves a combination of education about falls and screening for balance problems, with referral to personal physicians and home safety assessments. We developed a non-randomized statewide trial, Falls Free PA, to assess its effectiveness in reducing falls incidence over 12 months. We recruited 814 seniors who completed the program (503 first-time participants, 311 people repeating the program) and 1,020 who did not participate in the program, from the same sites. We assessed the quality of this non-randomized design by examining recruitment, follow-up across study groups, and comparability at baseline. Of older adults approached in senior centers, 90.5 % (n = 2,219) signed informed consent, and 1,834 (82.4 %) completed baseline assessments and were eligible for follow-up. Attrition in the three groups over 12 months was low and non-differential (<10 % for withdrawal and <2 % for other loss to follow-up). Median follow-up, which involved standardized monthly assessment of falls, was 10 months in all study groups. At baseline, the groups did not differ in measures of health or falls risk factors. Comparable status at baseline, recruitment from common sites, and similar experience with retention suggest that the non-randomized design will be effective for assessment of this approach to primary prevention of falls.

Department of Defense Dictionary of Military and Associated Terms

DTIC Science & Technology

2007-03-22

free drop; free fall; high velocity drop; low velocity drop. airdrop platform — A base upon which vehicles, cargo , or equipment are loaded for...displacement of cargo required to be carried by air for a specific task. See also airlift capability. airlift service — The performance or procurement of...effect. air priorities committee — (*) A committee set up to determine the priorities of passengers and cargo . air raid reporting control ship — (*) A

Temporal and spatial variability of frost-free seasons in the Great Lakes region of the United States

Treesearch

Lejiang Yu; Shiyuan Zhong; Xindi Bian; Warren E. Heilman; Jeffrey A. Andresen

2014-01-01

The frequency and timing of frost events and the length of the growing season are critical limiting factors in many human and natural ecosystems. This study investigates the temporal and spatial variability of the date of last spring frost (LSF), the date of first fall frost (FFF), and the length of the frost-free season (FFS) in the Great Lakes region of the United...

48 CFR 1523.7002 - Waivers.

Code of Federal Regulations, 2011 CFR

2011-10-01

... ENVIRONMENTAL, CONSERVATION, OCCUPATIONAL SAFETY, AND DRUG-FREE WORKPLACE Energy-Efficient Computer Equipment 1523.7002 Waivers. (a) There are several types of computer equipment which technically fall under the... types of equipment: (1) LAN servers, including file servers; application servers; communication servers...

48 CFR 1523.7002 - Waivers.

Code of Federal Regulations, 2012 CFR

2012-10-01

... ENVIRONMENTAL, CONSERVATION, OCCUPATIONAL SAFETY, AND DRUG-FREE WORKPLACE Energy-Efficient Computer Equipment 1523.7002 Waivers. (a) There are several types of computer equipment which technically fall under the... types of equipment: (1) LAN servers, including file servers; application servers; communication servers...

48 CFR 1523.7002 - Waivers.

Code of Federal Regulations, 2010 CFR

2010-10-01

... ENVIRONMENTAL, CONSERVATION, OCCUPATIONAL SAFETY, AND DRUG-FREE WORKPLACE Energy-Efficient Computer Equipment 1523.7002 Waivers. (a) There are several types of computer equipment which technically fall under the... types of equipment: (1) LAN servers, including file servers; application servers; communication servers...

Controlled release of free-falling test models

NASA Technical Reports Server (NTRS)

Fife, W. J.; Holway, H. P.

1970-01-01

Releasing device, powered by a drill motor through an adjustable speed reducer, has a spinning release head with three retractable spring-loaded fingers. The fingers are retracted by manual triggering of a cable at the motor end of the unit.

Executive Function and Falls in Older Adults: New Findings from a Five-Year Prospective Study Link Fall Risk to Cognition

PubMed Central

Mirelman, Anat; Herman, Talia; Brozgol, Marina; Dorfman, Moran; Sprecher, Elliot; Schweiger, Avraham; Giladi, Nir; Hausdorff, Jeffrey M.

2012-01-01

Background Recent findings suggest that executive function (EF) plays a critical role in the regulation of gait in older adults, especially under complex and challenging conditions, and that EF deficits may, therefore, contribute to fall risk. The objective of this study was to evaluate if reduced EF is a risk factor for future falls over the course of 5 years of follow-up. Secondary objectives were to assess whether single and dual task walking abilities, an alternative window into EF, were associated with fall risk. Methodology/Main Results We longitudinally followed 256 community-living older adults (age: 76.4±4.5 yrs; 61% women) who were dementia free and had good mobility upon entrance into the study. At baseline, a computerized cognitive battery generated an index of EF, attention, a closely related construct, and other cognitive domains. Gait was assessed during single and dual task conditions. Falls data were collected prospectively using monthly calendars. Negative binomial regression quantified risk ratios (RR). After adjusting for age, gender and the number of falls in the year prior to the study, only the EF index (RR: .85; CI: .74–.98, p = .021), the attention index (RR: .84; CI: .75–.94, p = .002) and dual tasking gait variability (RR: 1.11; CI: 1.01–1.23; p = .027) were associated with future fall risk. Other cognitive function measures were not related to falls. Survival analyses indicated that subjects with the lowest EF scores were more likely to fall sooner and more likely to experience multiple falls during the 66 months of follow-up (p<0.02). Conclusions/Significance These findings demonstrate that among community-living older adults, the risk of future falls was predicted by performance on EF and attention tests conducted 5 years earlier. The present results link falls among older adults to cognition, indicating that screening EF will likely enhance fall risk assessment, and that treatment of EF may reduce fall risk. PMID:22768271

Eccentric versus traditional resistance exercise for older adult fallers in the community: a randomized trial within a multi-component fall reduction program.

PubMed

LaStayo, Paul; Marcus, Robin; Dibble, Leland; Wong, Bob; Pepper, Ginette

2017-07-17

Addressing muscle deficits within a multi-component exercise fall reduction program is a priority, especially for the highest risk older adults, i.e., those who have fallen previously. Eccentric resistance exercise with its high-force producing potential, at a low energetic cost, may be ideally-suited to address muscle impairments in this population. The purpose of this study was to compare the effects of resistance exercise via negative, eccentrically-induced, work (RENEW) versus traditional (TRAD) resistance exercise on mobility, balance confidence, muscle power and cross sectional area, as well as the number of days high fall risk older adults survived without a fall event over a 1 year period. Randomized, two group, four time point (over 1 year) clinical trial testing RENEW versus TRAD as part of a 3 month multi-component exercise fall reduction program (MCEFRP). Primary outcomes of mobility, balance confidence, muscle power output and cross sectional area were analyzed using mixed effects modeling. The secondary outcomes of days to fall and days to near-fall were analyzed using survival analysis. The MCEFRP did have an effect on fall risk factors considered reversible with exercise interventions though there was no differential effect of RENEW versus TRAD (p = 0.896) on mobility, balance confidence, muscle power and cross sectional area. There were also no group differences in the number of days survived without a fall (p = 0.565) or near-fall (p = 0.678). Despite 100% of participants having at least one fall in the year prior to the MCEFRP, however, after 3 months of exercise and 9 months of follow-up <50% had experienced a fall or near fall. There were no differential effects of RENEW or TRAD as components of a MCEFRP on the primary or secondary outcomes. The two modes of resistance exercise had identical effects on fall risk and fall-free survival. NCT01080196 ; March 2, 2010 (retrospectively registered).

Method and apparatus for reading free falling dosimeter punchcodes

DOEpatents

Langsted, James M.

1992-12-22

A punchcode reader is provided for reading data encoded in a punchcode hole array on a dosimeter. The dosimeter falls through a passage in the reader containing photosensor detectors disposed along the passage which provide output signals to a microprocessor. The signals are processed to determine the orientation of the dosimeter in the reader, the location and state of punchcode holes in a two row array thereby decoding the encoded data. Multiple rate of fall calculations are made, and if appropriate matching of the punchcode array is not obtained in three tries, an error signal is outputted to the operator. The punchcode reader also provides for storage of data from multiple dosimeters passed through the reader, and for the output of decoded data to an external display or a computer for further processing.

The association between primary open-angle glaucoma and fall: an observational study.

PubMed

Tanabe, Sachiko; Yuki, Kenya; Ozeki, Naoki; Shiba, Daisuke; Tsubota, Kazuo

2012-01-01

Falls are among the most serious public health concerns for the elderly. Information conveyed via the visual sense is relevant to postural balance and movement, and proper visual function is essential to avoid falls. Here we investigated the prevalence of injurious falls among patients with primary open-angle glaucoma (POAG) who were more than 45 years old, compared with comparably aged healthy subjects. This is a cross-sectional study. Consecutive patients who visited the Tanabe Eye Clinic, Yamanashi, Japan between January 1 and March 30, 2009 were screened for eligibility by ophthalmic examination. A total of 117 control subjects (77 men, 40 women; aged 60.2 ± 7.5 years) who were free of ocular disease and 101 POAG patients (58 men, 43 women; aged 62.3 ± 8.7 years) were consecutively enrolled. Participants answered a questionnaire on injurious fall experience during the previous 10 years. The prevalence of injurious fall in subjects with POAG versus healthy controls was examined with Fisher's exact test. Adjusted odds ratios and 95% confidence intervals were estimated with logistic regression models for the subjects with POAG (factors: age, gender, mean deviation in the better eye or worse eye). The self-reported prevalence of injurious fall was 0.9% (1/117) in the control group and 6.9% (7/101) in the POAG group. The association between injurious fall and POAG was statistically significant (P = 0.026, Fisher's exact test). Within the POAG patients, the group reporting falls was significantly older and had a lower BMI, worse BCVA, and worse mean deviation in both the better and worse eye than the group reporting no falls. Worse mean deviation in the eye with the better visual field (odds ratios 0.75; 95% confidence intervals: 0.57 to 0.99; P = 0.036) was a significant risk factor for injurious falls in subjects with POAG. POAG was significantly associated with injurious falls.

Klamath Falls downtown development geothermal sidewalk snowmelt

DOE Office of Scientific and Technical Information (OSTI.GOV)

Brown, B.

1995-10-01

The Klamuth Falls, Oregon, downtown has seen a period of decline over the past 20 years as businesses have moved to new suburban shopping centers. Downtown business owners and the Klamuth Falls Downtown Redevelopment Agency are working to reverse that trend with a Downtown Streetscape Project intended to make the downtown a more pleasant place to work and do business. The visible elements of the project include new crosswalks with brick pavers, wheelchair ramps at sidewalk corners, new concrete sidewalks with a consistent decorative grid pattern, sidewalk planters for trees and flowers, and antique-style park benches and lighting fixtures. Amore » less visible, but equally valuable feature of the project is the plastic tubing installed under the sidewalks, wheelchair ramps and crosswalks, designed to keep them snow and ice free in the winter. A unique feature of the snowmelt system is the use of geothermal heated water on the return side of the Klamath Falls Geothermal District Heating System, made possible by the recent expansion of the district heating system.« less

Multi-Angle Snowflake Camera Instrument Handbook

DOE Office of Scientific and Technical Information (OSTI.GOV)

Stuefer, Martin; Bailey, J.

2016-07-01

The Multi-Angle Snowflake Camera (MASC) takes 9- to 37-micron resolution stereographic photographs of free-falling hydrometers from three angles, while simultaneously measuring their fall speed. Information about hydrometeor size, shape orientation, and aspect ratio is derived from MASC photographs. The instrument consists of three commercial cameras separated by angles of 36º. Each camera field of view is aligned to have a common single focus point about 10 cm distant from the cameras. Two near-infrared emitter pairs are aligned with the camera’s field of view within a 10-angular ring and detect hydrometeor passage, with the lower emitters configured to trigger the MASCmore » cameras. The sensitive IR motion sensors are designed to filter out slow variations in ambient light. Fall speed is derived from successive triggers along the fall path. The camera exposure times are extremely short, in the range of 1/25,000th of a second, enabling the MASC to capture snowflake sizes ranging from 30 micrometers to 3 cm.« less

The Pendulum: From Constrained Fall to the Concept of Potential

NASA Astrophysics Data System (ADS)

Bevilacqua, Fabio; Falomo, Lidia; Fregonese, Lucio; Giannetto, Enrico; Giudice, Franco; Mascheretti, Paolo

2006-08-01

Kuhn underlined the relevance of Galileo’s gestalt switch in the interpretation of a swinging body from constrained fall to time metre. But the new interpretation did not eliminate the older one. The constrained fall, both in the motion of pendulums and along inclined planes, led Galileo to the law of free fall. Experimenting with physical pendulums and assuming the impossibility of perpetual motion Huygens obtained a law of conservation of vis viva at specific positions, beautifully commented by Mach. Daniel Bernoulli generalised Huygens results introducing the concept of potential and the related independence of the ‘work’ done from the trajectories (paths) followed: vis viva conservation at specific positions is now linked with the potential. Feynman’s modern way of teaching the subject shows striking similarities with Bernoulli’s approach. A number of animations and simulations can help to visualise and teach some of the pendulum’s interpretations related to what we now see as instances of energy conservation.

Equilibrium and initial linear stability analysis of liquid metal falling film flows in a varying spanwise magnetic field

NASA Astrophysics Data System (ADS)

Gao, D.; Morley, N. B.

2002-12-01

A 2D model for MHD free surface flow in a spanwise field is developed. The model, designed to simulate film flows of liquid metals in future thermo­nuclear fusion reactors, considers an applied spanwise magnetic field with spatial and temporal variation and an applied streamwise external current. A special case - a thin falling film flow in spanwise magnetic field with constant gradient and constant applied external streamwise current, is here investigated in depth to gain insight into the behavior of the MHD film flow. The fully developed flow solution is derived and initial linear stability analysis is performed for this special case. It is seen that the velocity profile is significantly changed due to the presence of the MHD effect, resulting in the free surface analog of the classic M-shape velocity profile seen in developing pipe flows in a field gradient. The field gradient is also seen to destabilize the film flow under most conditions. The effect of external current depends on the relative direction of the field gradient to the current direction. By controlling the magnitude of an external current, it is possible to obtain a linearly stable falling film under these magnetic field conditions. Tables 1, Figs 12, Refs 20.

Questions Students Ask: How Can a Downhill Skier Move Faster than a Sky Diver?

ERIC Educational Resources Information Center

Armenti, Angelo, Jr.

1984-01-01

Discusses the relationship of gravity, coefficient of friction, surface area, and Newton's second law to explain the physics involved in downhill skiers being able to move faster than sky divers in free fall. (JM)

Weak Presentations in Introductory Physics Texts.

ERIC Educational Resources Information Center

Jacobs, Samuel

1978-01-01

Presents a few illustrations of physics areas such as capacitors, free fall, vectors, and waves, to show that methods of presentation of specific topics, in some physics textbooks, produce in the average student the wrong impression and ignorance of important scientific facts. (GA)

Research notes : new guidance on managing rockfall.

DOT National Transportation Integrated Search

2001-11-01

Hundreds of millions of dollars are spent annually in the U.S. to construct and maintain rock slopes and reduce rockfall hazards along highways. Rockfall occurs on slopes where rocks may free fall, bounce, roll or slide. Many factors cause rockfall, ...

Hydrodynamic water impact. [Apollo spacecraft waterlanding

NASA Technical Reports Server (NTRS)

Kettleborough, C. F.

1972-01-01

The hydrodynamic impact of a falling body upon a viscous incompressible fluid was investigated by numerically solving the equations of motion. Initially the mathematical model simulated the axisymmetric impact of a rigid right circular cylinder upon the initially quiescent free surface of a fluid. A compressible air layer exists between the falling cylinder and the liquid free surface. The mathematical model was developed by applying the Navier-Stokes equations to the incompressible air layer and the incompressible fluid. Assuming the flow to be one dimensional within the air layer, the average velocity, pressure and density distributions were calculated. The liquid free surface was allowed to deform as the air pressure acting on it increases. For the liquid the normalized equations were expressed in two-dimensional cylindrical coordinates. The governing equations for the air layer and the liquid were expressed in finite difference form and solved numerically. For the liquid a modified version of the Marker-and-Cell method was used. The mathematical model has been reexamined and a new approach has recently been initiated. Essentially this consists of examining the impact of an inclined plate onto a quiesent water surface with the equations now formulated in cartesian coordinates.

Changes in solidified microstructures

NASA Technical Reports Server (NTRS)

Wallace, J. F.

1984-01-01

The properties and casting behavior of metals are significantly affected by their cast structure. This structure is optimized by producing columnar versus equiaxed grains and coarse versus fine grains by controlling solidification conditions. The transition from columnar to equiaxed grains is favored by: constitutional supercooling with effective nucleation of free dendrites; melting off and transport of dendrite tips and arms; mechanical vibration; falling down of free dendrites from a chilled top surface; and induced flow in the solidifying structure by oscillation of rotation.

Slamming pressures on the bottom of a free-falling vertical wedge

NASA Astrophysics Data System (ADS)

Ikeda, C. M.; Judge, C. Q.

2013-11-01

High-speed planing boats are subjected to repeat impacts due to slamming, which can cause structural damage and injury to passengers. A first step in understanding and predicting the physics of a craft re-entering the water after becoming partially airborne is an experimental vertical drop test of a prismastic wedge (deadrise angle, β =20° beam, B = 300 mm; and length, L = 600 mm). The acrylic wedge was mounted to a rig allowing it to free-fall into a deep-water tank (5.2m × 5.2m × 4.2m deep) from heights 0 <= H <= 635 mm, measured from the keel to the free surface. The wedge was instrumented to record vertical position, acceleration, and pressure on the bottom surface. A pressure mapping system, capable of measuring several points over the area of the thin (0.1 mm) film sensor at sampling rates up to 20 kHz, is used and compared to surface-mounted pressure transducers (sampled at 10 kHz). A high speed camera (1000 fps, resolution of 1920 × 1200 pixels) is mounted above the wedge model to record the wetted surface as the wedge descended below the free surface. The pressure measurements taken with both conventional surface pressure transducers and the pressure mapping system agree within 10% of the peak pressure values (0.7 bar, typical). Supported by the Office of Naval Research.

Differences in Functional Fitness Among Older Adults With and Without Risk of Falling.

PubMed

Zhao, Yanan; Chung, Pak-Kwong

2016-03-01

This study aimed to identify the differences in functional fitness between older adults who were at risk of falling and those who were not. A total of 104 older adults aged 65-74 years were recruited from a local community senior center. They were independent older adults without a history of falls in the preceding 12 months. Falling risk status was assessed using the Fall Risk Test. Five dimensions of functional fitness with seven testing parameters (i.e., 30-second chair stand test, 30-second arm curl test, 2-minute step test, chair sit and reach test, back scratch test, 8-foot up and go test, and body mass index) were evaluated by the Senior Fitness Test. Only 78 participants completed all the tests, of which 48 participants were identified with risk of falling, and 30 participants were free from risk of falling. Results from multivariate analysis of variance found significant differences on the combined outcome variables, especially in the 8-foot up and go test, 2-minute step test, and 30-second arm curl test. Results from discriminant analysis found a significant discriminant function among all the seven testing parameters, where the 8-foot up and go test, and the 2-minute step test contributed most. Older adults who are at the early stage of risk of falling tend to have lower functional fitness capacities, especially in agility and dynamic balance, aerobic endurance as well as in a combined relationship among all the testing parameters. Copyright © 2016. Published by Elsevier B.V.

Financial Management during Crisis (For Parents)

MedlinePlus

... can find themselves on the brink of financial free-fall when medical expenses pile up. Even so, maintaining your family's financial health is not impossible. With organization and careful planning, you can learn to manage your money during a medical crisis. Costs of Health Care ...

Indirect (source-free) integration method. II. Self-force consistent radial fall

NASA Astrophysics Data System (ADS)

Ritter, Patxi; Aoudia, Sofiane; Spallicci, Alessandro D. A. M.; Cordier, Stéphane

2016-12-01

We apply our method of indirect integration, described in Part I, at fourth order, to the radial fall affected by the self-force (SF). The Mode-Sum regularization is performed in the Regge-Wheeler gauge using the equivalence with the harmonic gauge for this orbit. We consider also the motion subjected to a self-consistent and iterative correction determined by the SF through osculating stretches of geodesics. The convergence of the results confirms the validity of the integration method. This work complements and justifies the analysis and the results appeared in [Int. J. Geom. Meth. Mod. Phys. 11 (2014) 1450090].

Measuring the Newtonian constant of gravitation with a differential free-fall gradiometer: A feasibility study

NASA Astrophysics Data System (ADS)

Rothleitner, Christian; Francis, Olivier

2014-04-01

An original setup is presented to measure the Newtonian Constant of Gravitation G. It is based on the same principle as used in ballistic absolute gravimeters. The differential acceleration of three simultaneously freely falling test masses is measured in order to determine G. In this paper, a description of the experimental setup is presented. A detailed uncertainty budget estimates the relative uncertainty to be of the order of 5.3 × 10-4, however with some improvements a relative uncertainty in G of one part in 104 could be feasible.

A Photographic Study of Freezing of Water Droplets Falling Freely in Air

NASA Technical Reports Server (NTRS)

Dorsch, Robert G.; Levine, Joseph

1952-01-01

A photographic technique for investigating water droplets of diameter less than 200 microns falling freely in air at temperatures between 0 C and -50 C has been devised and used to determine: (i) The shape of frozen droplets (2) The occurrence of collisions of partly frozen or of frozen and liquid droplets (3) The statistics on the freezing temperatures of individual free-falling droplets A considerable number of droplets were found to have a nonspherical shape after freezing because of various protuberances and frost growth, and droplet aggregates formed by collision. The observed frequency of collision of partly frozen droplets showed good order of magnitude agreement with the frequency computed from theoretical collection efficiencies. The freezing temperature statistics indicated a general similarity of the data to those obtained for droplets frozen on a metallic surface in previous experiments.

Method and apparatus for reading free falling dosimeter punchcodes

DOE Office of Scientific and Technical Information (OSTI.GOV)

Langsted, J.M.

1992-12-22

A punchcode reader is provided for reading data encoded in a punchcode hole array on a dosimeter. The dosimeter falls through a passage in the reader containing photosensor detectors disposed along the passage which provide output signals to a microprocessor. The signals are processed to determine the orientation of the dosimeter in the reader, the location and state of punchcode holes in a two row array thereby decoding the encoded data. Multiple rate of fall calculations are made, and if appropriate matching of the punchcode array is not obtained in three tries, an error signal is output to the operator.more » The punchcode reader also provides for storage of data from multiple dosimeters passed through the reader, and for the output of decoded data to an external display or a computer for further processing. 8 figs.« less

Method and apparatus for reading free falling dosimeter punchcodes

DOEpatents

Langsted, J.M.

1992-12-22

A punchcode reader is provided for reading data encoded in a punchcode hole array on a dosimeter. The dosimeter falls through a passage in the reader containing photosensor detectors disposed along the passage which provide output signals to a microprocessor. The signals are processed to determine the orientation of the dosimeter in the reader, the location and state of punchcode holes in a two row array thereby decoding the encoded data. Multiple rate of fall calculations are made, and if appropriate matching of the punchcode array is not obtained in three tries, an error signal is output to the operator. The punchcode reader also provides for storage of data from multiple dosimeters passed through the reader, and for the output of decoded data to an external display or a computer for further processing. 8 figs.

Gravitational collapse of conventional polytropic cylinder

NASA Astrophysics Data System (ADS)

Lou, Yu-Qing; Hu, Xu-Yao

2017-07-01

In reference to general polytropic and conventional polytropic hydrodynamic cylinders of infinite length with axial uniformity and axisymmetry under self-gravity, the dynamic evolution of central collapsing mass string in free-fall dynamic accretion phase is re-examined in details. We compare the central mass accretion rate and the envelope mass infall rate at small radii. Among others, we correct mistakes and typos of Kawachi & Hanawa (KH hereafter) and in particular prove that their key asymptotic free-fall solution involving polytropic index γ in the two power exponents is erroneous by analytical analyses and numerical tests. The correct free-fall asymptotic solutions at sufficiently small \\hat{r} (the dimensionless independent self-similar variable) scale as {˜ } -|ln \\hat{r}|^{1/2} in contrast to KH's ˜ -|ln \\hat{r}|^{(2-γ )/2} for the reduced bulk radial flow velocity and as {˜ } \\hat{r}^{-1}|ln \\hat{r}|^{-1/2} in contrast to KH's {˜ } \\hat{r}^{-1} |ln \\hat{r}|^{-(2-γ )/2} for the reduced mass density. We offer consistent scenarios for numerical simulation code testing and theoretical study on dynamic filamentary structure formation and evolution as well as pertinent stability properties. Due to unavoidable Jeans instabilities along the cylinder, such collapsing massive filaments or strings can further break up into clumps and segments of various lengths as well as clumps embedded within segments and evolve into chains of gravitationally collapsed objects (such as gaseous planets, brown dwarfs, protostars, white dwarfs, neutron stars, black holes in a wide mass range, globular clusters, dwarf spheroidals, galaxies, galaxy clusters and even larger mass reservoirs etc.) in various astrophysical and cosmological contexts as articulated by Lou & Hu recently. As an example, we present a model scheme for comparing with observations of molecular filaments for forming protostars, brown dwarfs and gaseous planets and so forth.

Optimal rendezvous in the neighborhood of a circular orbit

NASA Technical Reports Server (NTRS)

Jones, J. B.

1975-01-01

The minimum velocity change rendezvous solutions, when the motion may be linearized about a circular orbit, fall into two separate regions; the phase-for-free region and the general region. Phase-for-free solutions are derived from the optimum transfer solutions, require the same velocity change expenditure, but may not be unique. Analytic solutions are presented in two of the three subregions. An algorithm is presented for determining the unique solutions in the general region. Various sources of initial conditions are discussed and three examples presented.

In silico free energy predictions for ionic liquid-assisted exfoliation of a graphene bilayer into individual graphene nanosheets.

PubMed

Kamath, Ganesh; Baker, Gary A

2012-06-14

Free energies for graphene exfoliation from bilayer graphene using ionic liquids based on various cations paired with the bis(trifluoromethylsulfonyl)imide anion were determined from adaptive bias force-molecular dynamics (ABF-MD) simulation and fall in excellent qualitative agreement with experiment. This method has notable potential as an a priori screening tool for performance based rank order prediction of novel ionic liquids for the dispersion and exfoliation of various nanocarbons and inorganic graphene analogues.

The Microgravity Demonstrator.

ERIC Educational Resources Information Center

Rogers, Melissa J. B.; Wargo, Michael J.

The Microgravity Demonstrator is a tool used to create microgravity conditions in the classroom. A series of demonstrations is used to provide a dramatically visual, physical connection between free-fall and microgravity conditions in order to understand why various types of experiments are performed under microgravity conditions. The manual is…

A case of survival of extreme vertical impact in seated position.

DOT National Transportation Integrated Search

1962-10-01

Physical, biophysical, and medical data are presented concerning the case of a 20-year-old male of excellent physical condition who jumped from the Golden Gate Bridge in San Francisco, surviving for ten days a free-fall deceleration in the seated pos...

Courseware Review.

ERIC Educational Resources Information Center

Risley, John S.

1983-01-01

Reviews "Laws of Motion" computer program produced by Educational Materials and Equipment Company. The program (language unknown), for Apple II/II+, is a simulation of an inclined plane, free fall, and Atwood machine in Newtonian/Aristotelian worlds. Suggests use as supplement to discussion of motion by teacher who fully understands the…

Description and Flight Performance Results of the WASP Sounding Rocket

NASA Technical Reports Server (NTRS)

De Pauw, J. F.; Steffens, L. E.; Yuska, J. A.

1968-01-01

A general description of the design and construction of the WASP sounding rocket and of the performance of its first flight are presented. The purpose of the flight test was to place the 862-pound (391-kg) spacecraft above 250 000 feet (76.25 km) on free-fall trajectory for at least 6 minutes in order to study the effect of "weightlessness" on a slosh dynamics experiment. The WASP sounding rocket fulfilled its intended mission requirements. The sounding rocket approximately followed a nominal trajectory. The payload was in free fall above 250 000 feet (76.25 km) for 6.5 minutes and reached an apogee altitude of 134 nautical miles (248 km). Flight data including velocity, altitude, acceleration, roll rate, and angle of attack are discussed and compared to nominal performance calculations. The effect of residual burning of the second stage motor is analyzed. The flight vibration environment is presented and analyzed, including root mean square (RMS) and power spectral density analysis.

Isotope-selective high-order interferometry with large organic molecules in free fall

NASA Astrophysics Data System (ADS)

Rodewald, Jonas; Dörre, Nadine; Grimaldi, Andrea; Geyer, Philipp; Felix, Lukas; Mayor, Marcel; Shayeghi, Armin; Arndt, Markus

2018-03-01

Interferometry in the time domain has proven valuable for matter-wave based measurements. This concept has recently been generalized to cold molecular clusters using short-pulse standing light waves which realized photo-depletion gratings, arranged in a time-domain Talbot–Lau interferometer (OTIMA). Here we extend this idea further to large organic molecules and demonstrate a new scheme to scan the emerging molecular interferogram in position space. The capability of analyzing different isotopes of the same monomer under identical conditions opens perspectives for studying the interference fringe shift as a function of time in gravitational free fall. The universality of OTIMA interferometry allows one to handle a large variety of particles. In our present work, quasi-continuous laser evaporation allows transferring fragile organic molecules into the gas phase, covering more than an order of magnitude in mass between 614 amu and 6509 amu, i.e. 300% more massive than in previous OTIMA experiments. For all masses, we find about 30% fringe visibility.

Transformation of a Water Slug in Free Fall Under the Conditions of Exposure to an Air Flow Orthogonal to the Direction of the Slug Motion

NASA Astrophysics Data System (ADS)

Volkov, R. S.; Zabelin, M. V.; Kuznetsov, G. V.; Strizhak, P. A.

2016-07-01

An experimental study has been made of the influence of an orthogonal (side) air flow propagating with a velocity to 5 m/s on the phases of transformation of a water slug with an initial volume of 0.05-0.5 liter in free fall from a height of 3 m. Use was made of Phantom V411 and Phantom Miro M310 high-speed video cameras and a Tema Automotive software system with the function of continuous tracking. The laws of retardation of the phases of transformation of the water slug from the instant of formation to that of formation of a droplet cloud under the action of the air flow orthogonal to the direction of the slug motion, and also of the deceleration, removal, and destruction of the droplets and fragments of water separating from the slug surface, have been established.

Simulated conditions of microgravity suppress progesterone production by luteal cells of the pregnant rat

NASA Technical Reports Server (NTRS)

Bhat, G. K.; Yang, H.; Sridaran, R.

2001-01-01

The purpose of this study was to assess whether simulated conditions of microgravity induce changes in the production of progesterone by luteal cells of the pregnant rat ovary using an in vitro model system. The microgravity environment was simulated using either a high aspect ratio vessel (HARV) bioreactor with free fall or a clinostat without free fall of cells. A mixed population of luteal cells isolated from the corpora lutea of day 8 pregnant rats was attached to cytodex microcarrier beads (cytodex 3). These anchorage dependent cells were placed in equal numbers in the HARV or a spinner flask control vessel in culture conditions. It was found that HARV significantly reduced the daily production of progesterone from day 1 through day 8 compared to controls. Scanning electron microscopy showed that cells attached to the microcarrier beads throughout the duration of the experiment in both types of culture vessels. Cells cultured in chamber slide flasks and placed in a clinostat yielded similar results when compared to those in the HARV. Also, when they were stained by Oil Red-O for lipid droplets, the clinostat flasks showed a larger number of stained cells compared to control flasks at 48 h. Further, the relative amount of Oil Red-O staining per milligram of protein was found to be higher in the clinostat than in the control cells at 48 h. It is speculated that the increase in the level of lipid content in cells subjected to simulated conditions of microgravity may be due to a disruption in cholesterol transport and/or lesions in the steroidogenic pathway leading to a fall in the synthesis of progesterone. Additionally, the fall in progesterone in simulated conditions of microgravity could be due to apoptosis of luteal cells.

Tuned mass damping system for a pendulum in gravity and microgravity fields

NASA Astrophysics Data System (ADS)

Atour, Farah

2016-07-01

An electrodynamic tether is a simple idea, but one with an amazing number of uses. Electrodynamic tether is a long conductor wire that is attached to the satellite, which can act as a generator or motor, from its motion through the earth's magnetic field. And it has the potential to make space travel significantly cheaper. The lack of electrodynamic tether's widespread in common applications can be attributed to the variable Lorentz forces occuring on the tethers, which will cause them to oscillate and may go out of control, de-orbit the satellite and fall to Earth. A tuned mass damper system, for short refered as tilger, is suggested as damper of oscillations of tethers. A system composed of a tuned mass damper and a simple pendulum simulating the tether was therefore constructed. 350 sets of experimental trials were done on the system, while it was installed inside a drop tower capsule resting on the ground, in order to pick four optimum setup experiments that will undergo a series of microgravity experiments at the Bremen Drop Tower in Bremen, Germany. The GJU Bachelor Research students found that the oscillations of the simple pendulum will not be affected by the tilger during the free fall experiment, except if a feedback mechanism is installed between the simple pendulum and the tilger. In this case, the tilger will dampen the simple pendulum oscillations during free fall.

Winter Cornucopia | Poster

Cancer.gov

By Andrea Frydl, Guest Writer Display Cases, Movies, and Raffles—Oh My! In December, Alicia Gussio (SAIC-Frederick) and Robert Koogle (NCI) were the lucky winners of free movie tickets to Regal theaters. They each correctly answered questions about Employee Diversity Team’s (EDT’s) November display case featuring the fall harvest.

Mars penetrator umbilical. [to study geophysical properties of Mars

NASA Technical Reports Server (NTRS)

Barns, C. E.

1979-01-01

The device proposed to gather subsurface data on the planet Mars is a ballistic probe which penetrates the soil after a free fall through the Martian atmosphere. Highlights of the design, development, and testing of several features of the Mars Surface Penetration Probe are outlined.

Registrars' Group Faces a Financial Free Fall.

ERIC Educational Resources Information Center

Gose, Ben

1998-01-01

The organizational transformation process begun several years ago by the American Association of Collegiate Registrars and Admissions Officers has resulted in the association's once-solid financial base collapsing, bringing internal tensions about the transformation to the surface. Debate centers on the organization's ability to be a policy leader…

Aerodynamic and engineering design of a 1.5 s high quality microgravity drop tower facility

NASA Astrophysics Data System (ADS)

Belser, Valentin; Breuninger, Jakob; Reilly, Matthew; Laufer, René; Dropmann, Michael; Herdrich, Georg; Hyde, Truell; Röser, Hans-Peter; Fasoulas, Stefanos

2016-12-01

Microgravity experiments are essential for research in space science, biology, fluid mechanics, combustion, and material sciences. One way to conduct microgravity experiments on Earth is by using drop tower facilities. These facilities combine a high quality of microgravity, adequate payload masses and have the advantage of virtually unlimited repeatability under same experimental conditions, at a low cost. In a collaboration between the Institute of Space Systems (IRS) at the University of Stuttgart and Baylor University (BU) in Waco, Texas, a new drop tower is currently under development at the Center for Astrophysics, Space Physics and Engineering Research (CASPER). The design parameters of the drop tower ask for at least 1.5 s in free fall duration while providing a quality of at least 10-5 g. Previously, this quality has only been achieved in vacuum drop tower facilities where the capsule experiences virtually zero aerodynamic drag during its free fall. Since this design comes at high costs, a different drop tower design concept, which does not require an evacuated drop shaft, was chosen. It features a dual-capsule system in which the experiment capsule is shielded from aerodynamic forces by surrounding it with a drag shield during the drop. As no other dual-capsule drop tower has been able to achieve a quality as good as or better than 10-5 g previous work optimized the design with an aerodynamic perspective by using computational fluid dynamics (CFD) simulations to determine the ideal shape and size of the outer capsule and to specify the aerodynamically crucial dimensions for the overall system. Experiments later demonstrated that the required quality of microgravity can be met with the proposed design. The main focus of this paper is the mechanical realization of the capsule as well as the development and layout of the surrounding components, such as the release mechanism, the deceleration device and the drop shaft. Because the drop tower facility is a complex system with many interdependencies between all of the components, several engineering challenges had to be addressed. For example, initial disturbances that are caused by the release mechanism are a common issue that arises at drop tower facilities. These vibrations may decrease the quality of microgravity during the initial segment of free fall. Because this would reduce the free fall time experiencing high quality microgravity, a mechanism has been developed to provide a soft release. Challenges and proposed solutions for all components are highlighted in this paper.

Why did the apple fall? A new model to explain Einstein’s gravity

NASA Astrophysics Data System (ADS)

Stannard, Warren; Blair, David; Zadnik, Marjan; Kaur, Tejinder

2017-01-01

Newton described gravity as an attractive force between two masses but Einstein’s General Theory of Relativity provides a very different explanation. Implicit in Einstein’s theory is the idea that gravitational effects are the result of a distortion in the shape of space-time. Despite its elegance, Einstein’s concept of gravity is rarely encountered outside of an advanced physics course as it is often considered to be too complex and too mathematical. This paper describes a new conceptual and quantitative model of gravity based on General Relativity at a level most science students should be able to understand. The model illustrates geodesics using analogies with paths of navigation on the surface of the Earth. This is extended to space and time maps incorporating the time warping effects of General Relativity. Using basic geometry, the geodesic path of a falling object near the surface of the Earth is found. From this the acceleration of an object in free fall is calculated. The model presented in this paper can answer the question, ‘Why do things fall?’ without resorting to Newton’s gravitational force.

Fall Chinook Salmon Survival and Supplementation Studies in the Snake River and Lower Snake River Reservoirs, 1995 Annual Report.

DOE Office of Scientific and Technical Information (OSTI.GOV)

Williams, John G.; Bjomn

1997-03-01

In 1994, the National Marine Fisheries Service and the US Fish and Wildlife Service began a cooperative study to investigate migrational characteristics of subyearling fall chinook salmon in the Snake River. The primary study objectives were to (1) determine the feasibility of estimating detection and passage survival probabilities of natural and hatchery subyearling fall chinook salmon released in the Snake River (Chapter 1), (2) investigate relationships between detection and passage survival probabilities and travel time of subyearling fall chinook salmon and environmental influences such as flow volume and water temperature (Chapter 1), (3) monitor and evaluate dispersal of hatchery subyearlingmore » chinook salmon into nearshore rearing areas used by natural fish (Chapter 2), and (4) monitor and evaluate travel time to Lower Granite Dam, growth from release in the Snake River to recapture at Lower Granite Dam, ATPase levels of fish recaptured at Lower Granite Dam, and survival from release in the free-flowing Snake River to the tailrace of Lower Granite Dam (Chapter 2).« less

Wearable vital parameters monitoring system

NASA Astrophysics Data System (ADS)

Caramaliu, Radu Vadim; Vasile, Alexandru; Bacis, Irina

2015-02-01

The system we propose monitors body temperature, heart rate and beside this, it tracks if the person who wears it suffers a faint. It uses a digital temperature sensor, a pulse sensor and a gravitational acceleration sensor to monitor the eventual faint or small heights free falls. The system continuously tracks the GPS position when available and stores the last valid data. So, when measuring abnormal vital parameters the module will send an SMS, using the GSM cellular network , with the person's social security number, the last valid GPS position for that person, the heart rate, the body temperature and, where applicable, a valid fall alert or non-valid fall alert. Even though such systems exist, they contain only faint detection or heart rate detection. Usually there is a strong correlation between low/high heart rate and an eventual faint. Combining both features into one system results in a more reliable detection device.

Progress towards a space-borne quantum gravity gradiometer

NASA Technical Reports Server (NTRS)

Yu, Nan; Kohel, James M.; Ramerez-Serrano, Jaime; Kellogg, James R.; Lim, Lawrence; Maleki, Lute

2004-01-01

Quantum interferometer gravity gradiometer for 3D mapping is a project for developing the technology of atom interferometer-based gravity sensor in space. The atom interferometer utilizes atomic particles as free fall test masses to measure inertial forces with unprecedented sensitivity and precision. It also allows measurements of the gravity gradient tensor components for 3D mapping of subsurface mass distribution. The overall approach is based on recent advances of laser cooling and manipulation of atoms in atomic and optical physics. Atom interferometers have been demonstrated in research laboratories for gravity and gravity gradient measurements. In this approach, atoms are first laser cooled to micro-kelvin temperatures. Then they are allowed to freefall in vacuum as true drag-free test masses. During the free fall, a sequence of laser pulses is used to split and recombine the atom waves to realize the interferometric measurements. We have demonstrated atom interferometer operation in the Phase I period, and we are implementing the second generation for a complete gradiometer demonstration unit in the laboratory. Along with this development, we are developing technologies at component levels that will be more suited for realization of a space instrument. We will present an update of these developments and discuss the future directions of the quantum gravity gradiometer project.

Net ozone photochemical production over the eastern and central North Pacific as inferred from GTE/CITE 1 observations during fall 1983

NASA Technical Reports Server (NTRS)

Chameides, W. L.; Davis, D. D.; Rodgers, M. O.; Bradshaw, J.; Sandholm, S.; Sachse, G.; Hill, G.; Gregory, G.

1987-01-01

The role of photochemistry in the budget of tropospheric ozone is studied. Measurements of O3, NO, CO, H2O vapor, and temperature obtained during the fall of 1983 during the GTE/CITE project over the eastern and central North Pacific Ocean are analyzed. The effect of altitude on the measurements is discussed. The analysis reveals a correlation between ozone and NO levels; both increase in concentration and variability with altitude. It is observed that an additional source of secondary importance associated wih CO-rich air parcels exists. A photochemical model is utilized to calculate the net rate of ozone production by photochemical reactions. A net photochemical source of ozone in the free troposphere and a net sink in the boundary layer are detected. The relation between the ozone source in the free troposphere and NO is examined. It is estimated that photochemistry provides a net ozone source to the free troposphere overlying the eastern and central North Pacific Ocean of about 5 x 10 to the 10th molecules/sq cm sec and a net sink of ozone to the boundary layer overlying this region of about 3 x 10 to the 10th molecules/sq cm sec.

The Mechanism of Extracellular Stimulation of Nerve Cells on an Electrolyte-Oxide-Semiconductor Capacitor

PubMed Central

Schoen, Ingmar; Fromherz, Peter

2007-01-01

Extracellular excitation of neurons is applied in studies of cultured networks and brain tissue, as well as in neuroprosthetics. We elucidate its mechanism in an electrophysiological approach by comparing voltage-clamp and current-clamp recordings of individual neurons on an insulated planar electrode. Noninvasive stimulation of neurons from pedal ganglia of Lymnaea stagnalis is achieved by defined voltage ramps applied to an electrolyte/HfO2/silicon capacitor. Effects on the smaller attached cell membrane and the larger free membrane are distinguished in a two-domain-stimulation model. Under current-clamp, we study the polarization that is induced for closed ion channels. Under voltage-clamp, we determine the capacitive gating of ion channels in the attached membrane by falling voltage ramps and for comparison also the gating of all channels by conventional variation of the intracellular voltage. Neuronal excitation is elicited under current-clamp by two mechanisms: Rising voltage ramps depolarize the free membrane such that an action potential is triggered. Falling voltage ramps depolarize the attached membrane such that local ion currents are activated that depolarize the free membrane and trigger an action potential. The electrophysiological analysis of extracellular stimulation in the simple model system is a basis for its systematic optimization in neuronal networks and brain tissue. PMID:17098803

Seasonal variation of energy reserves and reproduction in neotropical free-tailed bats Molossus molossus (Chiroptera: Molossidae).

PubMed

Barros, M S; Morais, D B; Araújo, M R; Carvalho, T F; Matta, S L P; Pinheiro, E C; Freitas, M B

2013-08-01

Seasonal variation is a key factor regulating energy metabolism and reproduction in several mammals, including bats. This study aimed to track seasonal changes in the energy reserves of the insectivorous bat Molossus molossus associated with its reproductive cycle. Adult males were collected during the four neotropical annual seasons in Viçosa - MG, Brazil. Blood and tissues were collected for metabolic analysis and testes were removed for histology and morphometry. Our results show that liver and breast muscle glycogen concentrations were significantly lower in winter. The adiposity index was significantly higher in the fall compared to winter and spring. Seminiferous tubules were greater in diameter in animals captured in fall and winter, indicating a higher investment in spermatic production during these seasons. The percentage of Leydig cells was higher in summer compared to fall and winter. We suggest that M. molossus presents a type of seasonal reproduction with two peaks of testicular activity: one in fall, with higher sperm production (spermatogenesis), and another in summer, with higher hormone production (steroidogenesis). The metabolic pattern may be associated with reproductive events, especially due to the highest fat storage observed in the fall, which coincides with the further development of the seminiferous tubules.

Layering of inertial confinement fusion targets in microgravity environments

NASA Astrophysics Data System (ADS)

Parks, P. B.; Fagaly, R. L.

1995-02-01

A critical concern in the fabrication of targets for inertial confinement fusion is ensuring that the hydrogenic (D2 or DT) fuel layer maintains spherical symmetry. Because of gravitationally induced sagging of the liquid prior to freezing, only relatively thin (less than 10 micrometers) layers of solid fuel can be produced by fast refreeze methods. One method to reduce the effective gravitational field environment is free-fall insertion into the target chamber. Another method to counterbalance the gravitational force is to use an applied magnetic field combined with a gradient field to induce a magnetic dipole force (F(sub m)) on the liquid fuel layer. For liquid deuterium, the required B dot product del(vector differential operator) B product to counterbalance the gravitational force (F(sub g)) is approximately 10 T(exp 2)/cm. In this paper, we examine the time-dependent dynamics of the liquid fuel layer in a reduced gravitational field environment. We employ an energy method which takes into account the sum of the free energy associated with the surface tension forces, net vertical force (F = F(sub m) - F(sub g) (in the case of magnetic field-assisted microgravity) or F(sub D) (the drag force in the case of free fall)), London-van der Waals forces, the kinetic energy of motion and viscous dissipation. By assuming that the motions are incompressible and irrotational, the volume integrals of the free energies over the deformed liquid fuel layer may be converted to surface integrals. With the surface expressed as the sum of Legendre polynomials, r(sub surface) = a + Sigma a(sub l)(t)P(sub l)(mu), the perturbed amplitude of the individual modes, a(sub l)(t) can be obtained. We show that the l = 1 vertical shift mode takes the longest to damp out, and may be problematic for free-fall insertion even for thin approximately 1 micrometer overfilled foam targets. For a given liquid fuel layer thickness delta, the equilibrium value of a(sub 1)/a (the concentricity of the inner fuel layer) is shown to be dependent on the net vertical force F and layer thickness, i.e., a(sub 1) approximately F delta(exp 5), but independent of the surface tension.

Fine structure of acoustic signals caused by a drop falling onto the surface of water

NASA Astrophysics Data System (ADS)

Chashechkin, Yu. D.; Prokhorov, V. E.

2015-08-01

The temporal structure of sound radiation upon a drop falling onto a free liquid surface is investigated experimentally by high-resolution high-speed videorecording synchronized with a broad-band measurement of the acoustic pressure. Groups of short and relatively prolonged sound packets with frequency filling from 2 to 50 kHz and the corresponding flow patterns including the simultaneous formation of resonating bubbles and their interaction processes with an originating cavern are isolated. The temporal dependence of the determining parameter, i.e., the Weber number, which is stably reproduced in a series of experiments by a power function with a fractional index, is constructed.

CCDs in the Mechanics Lab--A Competitive Alternative (Part II).

ERIC Educational Resources Information Center

Pinto, Fabrizio

1995-01-01

Describes a system of interactive astronomy whereby nonscience students are able to acquire their own images from a room remotely linked to a telescope. Briefly discusses some applications of Charge-Coupled Device cameras (CCDs) in teaching free fall, projectile motion, and the motion of the pendulum. (JRH)

Project Physics Text 1, Concepts of Motion.

ERIC Educational Resources Information Center

Harvard Univ., Cambridge, MA. Harvard Project Physics.

Fundamental concepts of motion are presented in this first unit of the Project Physics textbook. Descriptions of motion are made in connection with speeds, accelerations, and their graphical representation. Free-fall bodies are analyzed by using Aristotle's theory and Galileo's work. Dynamics aspects are discussed with a background of mass, force,…

The Paradoxes of Tolerance

ERIC Educational Resources Information Center

Pasamonik, Barbara

2004-01-01

Teachers who endeavor to build tolerant attitudes in their students often fall into the trap of political correctness. Political correctness can suspend free reflection on the differences inherent in otherness, which is the subject of tolerance, and creates an ideology of the generalized, abstract Other. As a result, teachers prefer to talk about…

Pendulum Rides, Rotations and the Coriolis Effect

ERIC Educational Resources Information Center

Pendrill, Ann-Marie; Modig, Conny

2018-01-01

An amusement park is full of examples that can be made into challenging problems for students, combining mathematical modelling with video analysis, as well as measurements in the rides. Traditional amusement ride related textbook problems include free-fall, circular motion, pendula and energy conservation in roller coasters, where the moving…

Around the Sun in a Graphing Calculator.

ERIC Educational Resources Information Center

Demana, Franklin; Waits, Bert K.

1989-01-01

Discusses the use of graphing calculators for polar and parametric equations. Presents eight lines of the program for the graph of a parametric equation and 11 lines of the program for a graph of a polar equation. Illustrates the application of the programs for planetary motion and free-fall motion. (YP)

Weyl invariance with a nontrivial mass scale

DOE Office of Scientific and Technical Information (OSTI.GOV)

Álvarez, Enrique; González-Martín, Sergio; Departamento de Física Teórica, Universidad Autónoma de Madrid,28049 Madrid

2016-09-07

A theory with a mass scale and yet Weyl invariant is presented. The theory is not invariant under all diffeomorphisms but only under transverse ones. This is the reason why Weyl invariance does not imply scale invariance in a free falling frame. Physical implications of this framework are discussed.

Simulating Gravity

ERIC Educational Resources Information Center

Pipinos, Savas

2010-01-01

This article describes one classroom activity in which the author simulates the Newtonian gravity, and employs the Euclidean Geometry with the use of new technologies (NT). The prerequisites for this activity were some knowledge of the formulae for a particle free fall in Physics and most certainly, a good understanding of the notion of similarity…

Green Team News and Upcoming Events | Poster

Cancer.gov

By Melissa Porter, Staff Writer Spring Plant Swap 2013 This past October, you may have seen several members of the Green Team standing in front of Building 549 giving out free plants or offering to take extra plants off your hands—this was the first Green Team Fall Plant Swap.

Report on the Effects of Parachutes on Risk Mitigation to Third Party Property and Individuals

DOT National Transportation Integrated Search

1993-03-01

This report looks at what research has been done to evaluate the public's risk by descent of a payload from its orbital or suborbital flight. Compared is the difference in risk between a parachute descent and that in free fall. The research indicates...

Manipulation strategies for massive space payloads

NASA Technical Reports Server (NTRS)

Book, Wayne J.

1991-01-01

Motion planning and control for the joints of flexible manipulators are discussed. Specific topics covered include control of a flexible braced manipulator, control of a small working robot on a large flexible manipulator to suppress vibrations, control strategies for ensuring cooperation among disparate manipulators, and motion planning for robots in free-fall.

Influence of cover crops on arthropods, free-living nematodes, and yield in a succeeding no-till soybean crop

USDA-ARS?s Scientific Manuscript database

Production practices that incorporate fall-planted cover crops into no-till agronomic crop rotations have become increasingly popular across the Northeastern United States for weed suppression and enhancing environmental stewardship. Field experiments were conducted in 2011 and 2012 to investigate e...

Demonstration of Ice-Free Cathodic Protection Systems for Water Storage Tanks at Fort Drum: Final Report on Project AR-F-318 for FY05

DTIC Science & Technology

2007-06-01

and immovable with fingers. Body side rivet base and outside rivet burr should be flat against the material. Bent rivets will fail under stress ...such as using knots, tying around sharp edges, etc.) and maximum permitted free fall distance. Also, to be stressed are the importance of inspections...limitations; e. Application limits; f. Proper hook -up, anchoring and tie-off techniques, including the proper dee-ring or other attachment point to use on

Optimal rendezvous in the neighborhood of a circular orbit

NASA Technical Reports Server (NTRS)

Jones, J. B.

1976-01-01

The minimum velocity-change rendezvous solutions, when the motion may be linearized about a circular orbit, fall into two separate regions; the phase-for-free region and the general region. Phase-for-free solutions are derived from the optimum transfer solutions, require the same velocity-change expenditure, but may not be unique. Analytic solutions are presented in two of the three subregions. An algorithm is presented for determining the unique solutions in the general region. Various sources of initial conditions are discussed and three examples are presented.

Three-dimensional low Reynolds number flows with a free surface

NASA Technical Reports Server (NTRS)

Degani, D.; Gutfinger, C.

1977-01-01

The two-dimensional leveling problem (Degani, Gutfinger, 1976) is extended to three dimensions in the case where the flow Re number is very low and attention is paid to the free surface boundary condition with surface tension effects included. The no-slip boundary condition on the wall is observed. The numerical solution falls back on the Marker and Cell (MAC) method (Harlow and Welch, 1965) with the computation region divided into a finite number of stationary rectangular cells (or boxes in the 3-D case) and fluid flow traverses the cells (or boxes).

Research of metal solidification in zero-g state. [test apparatus and instrumentation

NASA Technical Reports Server (NTRS)

Aubin, W. M.; Larson, D., Jr.; Geschwind, G. I.

1973-01-01

An experiment test apparatus that allows metal melting and resolidification in the three seconds available during free fall in a drop tower was built and tested in the tower. Droplets (approximately 0.05 cm) of pure nickel and 1090 steel were prepared in this fashion. The apparatus, including instrumentation, is described. As part of the instrumentation, a method for measuring temperature-time histories of the free floating metal droplets was developed. Finally, a metallurgical analysis of the specimens prepared in the apparatus is presented.

More Power to Schools

ERIC Educational Resources Information Center

Olson, Lynn

2007-01-01

After a period of top-down control under the mayor, the New York City system is freeing schools to run their own affairs--and holding them accountable for results. This fall, for the first time, each of the district's 1,456 public schools gained unprecedented control over budgetary and instructional decisions that previously resided with the…

Articulated Multimedia Physics, Lesson 12, Work, Energy, and Power.

ERIC Educational Resources Information Center

New York Inst. of Tech., Old Westbury.

As the twelfth lesson of the Articulated Multimedia Physics Course, instructional materials are presented in this study guide with relation to work, energy, and power. The topics are concerned with kinetic and potential energy, energy transfer in free falling bodies, and conservation laws. The content is arranged in scrambled form, and the use of…

Mechanical Study of a Modern Yo-Yo

ERIC Educational Resources Information Center

de Izarra, Charles

2011-01-01

This paper presents the study of a modern yo-yo having a centrifugal clutch allowing the free rolling. First, the mechanical parts of the yo-yo are measured, allowing us to determine analytically its velocity according to its height of fall. Then, we are more particularly interested in the centrifugal device constituted by springs and small…

46 CFR 108.540 - Survival craft muster and embarkation arrangements.

Code of Federal Regulations, 2013 CFR

2013-10-01

... OFFSHORE DRILLING UNITS DESIGN AND EQUIPMENT Lifesaving Equipment § 108.540 Survival craft muster and... minutes from the time the instruction to board is given. (e) Each davit-launched and free-fall survival... ladder as follows: (1) Each embarkation ladder must be approved under approval series 160.117 or be a...

Wireless Drop Tower for Microgravity Demonstrations. Educational Brief.

ERIC Educational Resources Information Center

National Aeronautics and Space Administration, Washington, DC.

Microgravity-the absence or reduction of some of the effects of gravity-is an important attribute of free-fall. In microgravity (often incorrectly called zero-g), water no longer flows "downhill" and neither do smoke or steam bubbles rise. This changes a number of chemical and physical activities. Experiments in combustion, fluid behavior,…

30 CFR 75.371 - Mine ventilation plan; contents.

Code of Federal Regulations, 2010 CFR

2010-07-01

... adequately maintaining bleeder entries free of obstructions such as roof falls and standing water (see § 75... sensors are installed. (ii) The locations (designated areas) where dust measurements would be made in the... with §§ 75.350(c) and 75.350(d)(5). (mm) The location of any diesel-discriminating sensor, and...

Long term spatial and temporal trends in frost day indices in Kansas, USA

USDA-ARS?s Scientific Manuscript database

Frost day indices such as number of frost days (nFDs), frost free days (nFFDs), last spring freeze (LSF), first fall freeze (FFF), and growing-season length (GSL), were calculated using daily minimum air temperature (Tmin) values from 23 centennial weather stations spread across Kansas during four t...

Getting the Pieces to Fall into Place

ERIC Educational Resources Information Center

Conner, John A., Jr.; Gaddy, Katherine

1978-01-01

Documented here is the story of how a small town's recreation department, faced with limited resources of its own, mobilized diverse members of the community to fill the gaps in its summer recreation program. New activities--free daily lunches, girls' softball, canoe lessons--were instituted, and a unique citizen partnership was forged. (Author/DS)

Using a Digital Video Camera to Study Motion

ERIC Educational Resources Information Center

Abisdris, Gil; Phaneuf, Alain

2007-01-01

To illustrate how a digital video camera can be used to analyze various types of motion, this simple activity analyzes the motion and measures the acceleration due to gravity of a basketball in free fall. Although many excellent commercially available data loggers and software can accomplish this task, this activity requires almost no financial…

Incentivized: Realistic Carrots for Institutional and Student Improvement

ERIC Educational Resources Information Center

Violino, Bob

2012-01-01

As the focus on student success and completion intensifies on campus, community college leaders know the only way to stay viable is to change the culture of their institutions. With state and federal coffers in perpetual free fall, that means leveraging existing resources to spur reforms. Some colleges have attempted to do this through the…

New Way to Break Down Barriers to Higher Education: Build "Financial Capabilities"

ERIC Educational Resources Information Center

Savage, Sarah; Graves, Erin M.

2015-01-01

Community colleges have traditionally responded to the financial needs of their students by removing or minimizing financial barriers to attending. Efforts to make community college tuition free fit with this philosophy, but where efforts to minimize or remove financial barriers to attending community college fall short is in empowering students…

Analyzing Collision Processes with the Smartphone Acceleration Sensor

ERIC Educational Resources Information Center

Vogt, Patrik; Kuhn, Jochen

2014-01-01

It has been illustrated several times how the built-in acceleration sensors of smartphones can be used gainfully for quantitative experiments in school and university settings (see the overview in Ref. 1 ). The physical issues in that case are manifold and apply, for example, to free fall, radial acceleration, several pendula, or the exploitation…

In Summary: State Superintendent's Fall Conference for School District Administrators (September 15-16, 1982).

ERIC Educational Resources Information Center

Wisconsin State Dept. of Public Instruction, Madison.

This document summarizes seven speeches on educational issues in Wisconsin. Dr. Ernest Boyer advocates recognition and reward for quality teachers and identifies developing language skills as the essential purpose of public education. Dr. Carolyn Warner defends free public education and criticizes tuition tax credits. Dr. James Rutherford urges…

Keeping FCS Relevant with Technology

ERIC Educational Resources Information Center

Hays, Annette

2007-01-01

Acorn School campus is located in the shadow of Rich Mountain, near Mena, Arizona. In fall 2006, the school enrollment (K-12) was 476 students, with 76% eligible for free or reduced-cost meals. Its one-teacher family and consumer services (FCS) department offers two programs of study: Family and Consumer Sciences Education and Food Production…

The Kalamazoo Promise and Perceived Changes in School Climate

ERIC Educational Resources Information Center

Miron, Gary; Jones, Jeffrey N.; Kelaher-Young, Allison J.

2011-01-01

The Kalamazoo Promise was announced in the fall of 2005, offering free college tuition at any public state college or university for graduates of the district who have gained acceptance to a postsecondary institution. This program was funded through the generous support of anonymous donors, and a federally-funded evaluation is underway to examine…

29 CFR Appendix E to Subpart M of... - Sample Fall Protection Plan

Code of Federal Regulations, 2010 CFR

2010-07-01

... through holes and openings in walking/working surfaces. Each employee will be trained in these procedures..., implemented, monitored and enforced by any one individual. The total objective of a safe, accident free work environment can only be accomplished by a dedicated, concerted effort by every individual involved with the...

Safety First: Houston, We Have Liftoff!

ERIC Educational Resources Information Center

Roy, Ken

2014-01-01

A thrown basketball, a kicked football, an elastically launched catapult payload, and a free-falling solid fuel or pressurized gas-propelled rocket all have one thing in common. They are all projectiles familiar to elementary students. A projectile is an object thrown with an initial velocity and then allowed to move without thrust along its…

Pendula, Models, Constructivism and Reality

ERIC Educational Resources Information Center

Nola, Robert

2004-01-01

It is argued that Galileo made an important breakthrough in the methodology of science by considering idealized models of phenomena such as free fall, swinging pendula and the like, which can conflict with experience. The idealized models are constructs largely by our reasoning processes applied to the theoretical situation at hand. On this view,…

Simple Examples of the Interpretation of Changes in Kinetic and Potential Energy under Galilean Transformations

ERIC Educational Resources Information Center

Ginsberg, Edw S.

2018-01-01

The compatibility of the Newtonian formulation of mechanical energy and the transformation equations of Galilean relativity is demonstrated for three simple examples of motion treated in most introductory physics courses (free fall, a frictionless inclined plane, and a mass/spring system). Only elementary concepts and mathematics, accessible to…

Characterization of Vertical Impact Device Acceleration Pulses Using Parametric Assessment: Phase II Accelerated Free-Fall

DTIC Science & Technology

2016-04-30

support contractor , Infoscitex, conducted a series of tests to identify the performance capabilities of the Vertical Impact Device (VID). The VID is a...C. Table 3. AFD Evaluation with Red IMPAC Programmer: Data Summary Showing Means and Standard Deviations Test Cell Drop Ht . (in) Mean Peak

Hands-On Experiences with Buoyant-Less Water

ERIC Educational Resources Information Center

Slisko, Josip; Planinsic, Gorazd

2010-01-01

The phenomenon of weightlessness is known to students thanks to videos of amazing things astronauts do in spaceships orbiting the Earth. In this article we propose two hands-on activities which give students opportunities to infer by themselves the absence of buoyant force in a gravity accelerated system. The system is a free-falling or vertically…

Reading Pictures: An Interview with David Wiesner

ERIC Educational Resources Information Center

Varga-Dobai, Kinga

2008-01-01

Two-time Caldecott Honor winner (Free Fall, Sector 7) and three-time Caldecott Medal winner (Tuesday, The Three Pigs, Flotsam), David Wiesner is regarded as one of the most remarkable creators of visual storytelling living today. Wiesner is well known for his innovative and unique subject matter and his sophisticated painting-like illustrations…

a Molecular Fountain

NASA Astrophysics Data System (ADS)

Cheng, Cunfeng; van der Poel, Aernout P. P.; Ubachs, Wim; Bethlem, Hendrick

2017-06-01

The resolution of any spectroscopic experiment is limited by the coherent interaction time between the probe radiation and the particle that is being studied. The introduction of cooling techniques for atoms and ions has resulted in a dramatic increase of interaction times and accuracy, it is hoped that molecular cooling techniques will lead to a similar increase. Here we demonstrate the first molecular fountain, a development which permits hitherto unattainably long interrogation times with molecules. In our experiment, beams of ammonia molecules are decelerated, trapped and cooled using inhomogeneous electric fields and subsequently launched. Using a combination of quadrupole lenses and buncher elements, the beam is shaped such that it has a large position spread and a small velocity spread (corresponding to a transverse temperature of less than 10μK and a longitudinal temperature of less than 1μK) while the molecules are in free fall, but strongly focused at the detection region. The molecules are in free fall for up to 266 milliseconds, making it possible, in principle, to perform sub-Hz measurements in molecular systems and paving the way for stringent tests of fundamental physics theories.

Charge-Induced Force Noise on Free-Falling Test Masses: Results from LISA Pathfinder

NASA Astrophysics Data System (ADS)

Armano, M.; Audley, H.; Auger, G.; Baird, J. T.; Binetruy, P.; Born, M.; Bortoluzzi, D.; Brandt, N.; Bursi, A.; Caleno, M.; Cavalleri, A.; Cesarini, A.; Cruise, M.; Danzmann, K.; de Deus Silva, M.; Diepholz, I.; Dolesi, R.; Dunbar, N.; Ferraioli, L.; Ferroni, V.; Fitzsimons, E. D.; Flatscher, R.; Freschi, M.; Gallegos, J.; García Marirrodriga, C.; Gerndt, R.; Gesa, L.; Gibert, F.; Giardini, D.; Giusteri, R.; Grimani, C.; Grzymisch, J.; Harrison, I.; Heinzel, G.; Hewitson, M.; Hollington, D.; Hueller, M.; Huesler, J.; Inchauspé, H.; Jennrich, O.; Jetzer, P.; Johlander, B.; Karnesis, N.; Kaune, B.; Killow, C. J.; Korsakova, N.; Lloro, I.; Liu, L.; López-Zaragoza, J. P.; Maarschalkerweerd, R.; Madden, S.; Mance, D.; Martín, V.; Martin-Polo, L.; Martino, J.; Martin-Porqueras, F.; Mateos, I.; McNamara, P. W.; Mendes, J.; Mendes, L.; Moroni, A.; Nofrarias, M.; Paczkowski, S.; Perreur-Lloyd, M.; Petiteau, A.; Pivato, P.; Plagnol, E.; Prat, P.; Ragnit, U.; Ramos-Castro, J.; Reiche, J.; Romera Perez, J. A.; Robertson, D. I.; Rozemeijer, H.; Rivas, F.; Russano, G.; Sarra, P.; Schleicher, A.; Slutsky, J.; Sopuerta, C.; Sumner, T. J.; Texier, D.; Thorpe, J. I.; Trenkel, C.; Vetrugno, D.; Vitale, S.; Wanner, G.; Ward, H.; Wass, P. J.; Wealthy, D.; Weber, W. J.; Wittchen, A.; Zanoni, C.; Ziegler, T.; Zweifel, P.; LISA Pathfinder Collaboration

2017-04-01

We report on electrostatic measurements made on board the European Space Agency mission LISA Pathfinder. Detailed measurements of the charge-induced electrostatic forces exerted on free-falling test masses (TMs) inside the capacitive gravitational reference sensor are the first made in a relevant environment for a space-based gravitational wave detector. Employing a combination of charge control and electric-field compensation, we show that the level of charge-induced acceleration noise on a single TM can be maintained at a level close to 1.0 fm s-2 Hz-1 /2 across the 0.1-100 mHz frequency band that is crucial to an observatory such as the Laser Interferometer Space Antenna (LISA). Using dedicated measurements that detect these effects in the differential acceleration between the two test masses, we resolve the stochastic nature of the TM charge buildup due to interplanetary cosmic rays and the TM charge-to-force coupling through stray electric fields in the sensor. All our measurements are in good agreement with predictions based on a relatively simple electrostatic model of the LISA Pathfinder instrument.

Dual matter-wave inertial sensors in weightlessness

PubMed Central

Barrett, Brynle; Antoni-Micollier, Laura; Chichet, Laure; Battelier, Baptiste; Lévèque, Thomas; Landragin, Arnaud; Bouyer, Philippe

2016-01-01

Quantum technology based on cold-atom interferometers is showing great promise for fields such as inertial sensing and fundamental physics. However, the finite free-fall time of the atoms limits the precision achievable on Earth, while in space interrogation times of many seconds will lead to unprecedented sensitivity. Here we realize simultaneous 87Rb–39K interferometers capable of operating in the weightless environment produced during parabolic flight. Large vibration levels (10−2 g Hz−1/2), variations in acceleration (0–1.8 g) and rotation rates (5° s−1) onboard the aircraft present significant challenges. We demonstrate the capability of our correlated quantum system by measuring the Eötvös parameter with systematic-limited uncertainties of 1.1 × 10−3 and 3.0 × 10−4 during standard- and microgravity, respectively. This constitutes a fundamental test of the equivalence principle using quantum sensors in a free-falling vehicle. Our results are applicable to inertial navigation, and can be extended to the trajectory of a satellite for future space missions. PMID:27941928

Physics in ``Polymers, Composites, and Sports Materials" an Interdisciplinary Course

NASA Astrophysics Data System (ADS)

Hagedorn, Eric; Suskavcevic, Milijana

2007-10-01

The undergraduate science course described uses the themes of polymers and composites, as used in sports materials, to teach some key concepts in introductory chemistry and physics. The course is geared towards students who are interested in science, but are still completing prerequisite mathematics courses required for science majors. Each class is built around a laboratory activity. Atoms, molecules and chemical reactions are taught in reference to making polyvinyl acetate (white glue) and polyvinyl alcohol (gel glue). These materials, combined with borax, form balls which are subsequently used in physics activities centered on free-fall and the coefficient of restitution. These activities allow the introduction of kinematics and dynamics. A free fall activity involving ice pellets, with and without embedded tissue paper, illustrates the properties of composites. The final series of activities uses balls, shoes, racquets and bats to further illustrate dynamics concepts (including friction, momentum and energy). The physical properties of these sports objects are discussed in terms of the materials of which they are made. The evaluation plan to determine the effectiveness of these activities and preliminary results are also presented.

Charge-Induced Force Noise on Free-Falling Test Masses: Results from LISA Pathfinder.

PubMed

Armano, M; Audley, H; Auger, G; Baird, J T; Binetruy, P; Born, M; Bortoluzzi, D; Brandt, N; Bursi, A; Caleno, M; Cavalleri, A; Cesarini, A; Cruise, M; Danzmann, K; de Deus Silva, M; Diepholz, I; Dolesi, R; Dunbar, N; Ferraioli, L; Ferroni, V; Fitzsimons, E D; Flatscher, R; Freschi, M; Gallegos, J; García Marirrodriga, C; Gerndt, R; Gesa, L; Gibert, F; Giardini, D; Giusteri, R; Grimani, C; Grzymisch, J; Harrison, I; Heinzel, G; Hewitson, M; Hollington, D; Hueller, M; Huesler, J; Inchauspé, H; Jennrich, O; Jetzer, P; Johlander, B; Karnesis, N; Kaune, B; Killow, C J; Korsakova, N; Lloro, I; Liu, L; López-Zaragoza, J P; Maarschalkerweerd, R; Madden, S; Mance, D; Martín, V; Martin-Polo, L; Martino, J; Martin-Porqueras, F; Mateos, I; McNamara, P W; Mendes, J; Mendes, L; Moroni, A; Nofrarias, M; Paczkowski, S; Perreur-Lloyd, M; Petiteau, A; Pivato, P; Plagnol, E; Prat, P; Ragnit, U; Ramos-Castro, J; Reiche, J; Romera Perez, J A; Robertson, D I; Rozemeijer, H; Rivas, F; Russano, G; Sarra, P; Schleicher, A; Slutsky, J; Sopuerta, C; Sumner, T J; Texier, D; Thorpe, J I; Trenkel, C; Vetrugno, D; Vitale, S; Wanner, G; Ward, H; Wass, P J; Wealthy, D; Weber, W J; Wittchen, A; Zanoni, C; Ziegler, T; Zweifel, P

2017-04-28

We report on electrostatic measurements made on board the European Space Agency mission LISA Pathfinder. Detailed measurements of the charge-induced electrostatic forces exerted on free-falling test masses (TMs) inside the capacitive gravitational reference sensor are the first made in a relevant environment for a space-based gravitational wave detector. Employing a combination of charge control and electric-field compensation, we show that the level of charge-induced acceleration noise on a single TM can be maintained at a level close to 1.0  fm s^{-2} Hz^{-1/2} across the 0.1-100 mHz frequency band that is crucial to an observatory such as the Laser Interferometer Space Antenna (LISA). Using dedicated measurements that detect these effects in the differential acceleration between the two test masses, we resolve the stochastic nature of the TM charge buildup due to interplanetary cosmic rays and the TM charge-to-force coupling through stray electric fields in the sensor. All our measurements are in good agreement with predictions based on a relatively simple electrostatic model of the LISA Pathfinder instrument.

Characteristics of Gaseous Diffusion Flames with High Temperature Combustion Air in Microgravity

NASA Technical Reports Server (NTRS)

Ghaderi, M.; Gupta, A. K.

2003-01-01

The characteristics of gaseous diffusion flames have been obtained using high temperature combustion air under microgravity conditions. The time resolved flame images under free fall microgravity conditions were obtained from the video images obtained. The tests results reported here were conducted using propane as the fuel and about 1000 C combustion air. The burner included a 0.686 mm diameter central fuel jet injected into the surrounding high temperature combustion air. The fuel jet exit Reynolds number was 63. Several measurements were taken at different air preheats and fuel jet exit Reynolds number. The resulting hybrid color flame was found to be blue at the base of the flame followed by a yellow color flame. The length and width of flame during the entire free fall conditions has been examined. Also the relative flame length and width for blue and yellow portion of the flame has been examined under microgravity conditions. The results show that the flame length decreases and width increases with high air preheats in microgravity condition. In microgravity conditions the flame length is larger with normal temperature combustion air than high temperature air.

A vibration correction method for free-fall absolute gravimeters

NASA Astrophysics Data System (ADS)

Qian, J.; Wang, G.; Wu, K.; Wang, L. J.

2018-02-01

An accurate determination of gravitational acceleration, usually approximated as 9.8 m s-2, has been playing an important role in the areas of metrology, geophysics, and geodetics. Absolute gravimetry has been experiencing rapid developments in recent years. Most absolute gravimeters today employ a free-fall method to measure gravitational acceleration. Noise from ground vibration has become one of the most serious factors limiting measurement precision. Compared to vibration isolators, the vibration correction method is a simple and feasible way to reduce the influence of ground vibrations. A modified vibration correction method is proposed and demonstrated. A two-dimensional golden section search algorithm is used to search for the best parameters of the hypothetical transfer function. Experiments using a T-1 absolute gravimeter are performed. It is verified that for an identical group of drop data, the modified method proposed in this paper can achieve better correction effects with much less computation than previous methods. Compared to vibration isolators, the correction method applies to more hostile environments and even dynamic platforms, and is expected to be used in a wider range of applications.

Modelling supermassive black hole growth: towards an improved sub-grid prescription

NASA Astrophysics Data System (ADS)

Hobbs, Alexander; Power, Chris; Nayakshin, Sergei; King, Andrew R.

2012-04-01

Accretion on to supermassive black holes (SMBHs) in galaxy formation simulations is frequently modelled by the Bondi-Hoyle formalism. Here we examine the validity of this approach analytically and numerically. We argue that the character of the flow where one evaluates the gas properties is unlikely to satisfy the simple Bondi-Hoyle model. Only in the specific case of hot virialized gas with zero angular momentum and negligible radiative cooling is the Bondi-Hoyle solution relevant. In the opposite extreme, where the gas is in a state of free-fall at the evaluation radius due to efficient cooling and the dominant gravity of the surrounding halo, the Bondi-Hoyle formalism can be erroneous by orders of magnitude in either direction. This may impose artificial trends with halo mass in cosmological simulations by being wrong by different factors for different halo masses. We propose an expression for the sub-grid accretion rate which interpolates between the free-fall regime and the Bondi-Hoyle regime, therefore taking account of the contribution of the halo to the gas dynamics.

Constraints on LISA Pathfinder's Self-Gravity: Design Requirements, Estimates and Testing Procedures

NASA Technical Reports Server (NTRS)

Armano, M.; Audley, H.; Auger, G.; Baird, J.; Binetruy, P.; Born, M.; Bortoluzzi, M.; Brandt, Nico; Bursi, Alessandro; Slutsky. J.;

Unsteady aerodynamic forces and torques on falling parallelograms in coupled tumbling-helical motions

NASA Astrophysics Data System (ADS)

Varshney, Kapil; Chang, Song; Wang, Z. Jane

2013-05-01

Falling parallelograms exhibit coupled motion of autogyration and tumbling, similar to the motion of falling tulip seeds, unlike maple seeds which autogyrate but do not tumble, or rectangular cards which tumble but do not gyrate. This coupled tumbling and autogyrating motion are robust, when card parameters, such as aspect ratio, internal angle, and mass density, are varied. We measure the three-dimensional (3D) falling kinematics of the parallelograms and quantify their descending speed, azimuthal rotation, tumbling rotation, and cone angle in each falling. The cone angle is insensitive to the variation of the card parameters, and the card tumbling axis does not overlap with but is close to the diagonal axis. In addition to this connection to the dynamics of falling seeds, these trajectories provide an ideal set of data to analyze 3D aerodynamic force and torque at an intermediate range of Reynolds numbers, and the results will be useful for constructing 3D aerodynamic force and torque models. Tracking these free falling trajectories gives us a nonintrusive method for deducing instantaneous aerodynamic forces. We determine the 3D aerodynamic forces and torques based on Newton-Euler equations. The dynamical analysis reveals that, although the angle of attack changes dramatically during tumbling, the aerodynamic forces have a weak dependence on the angle of attack. The aerodynamic lift is dominated by the coupling of translational and rotational velocities. The aerodynamic torque has an unexpectedly large component perpendicular to the card. The analysis of the Euler equation suggests that this large torque is related to the deviation of the tumbling axis from the principle axis of the card.

Unsteady aerodynamic forces and torques on falling parallelograms in coupled tumbling-helical motions.

PubMed

Varshney, Kapil; Chang, Song; Wang, Z Jane

2013-05-01

Falling parallelograms exhibit coupled motion of autogyration and tumbling, similar to the motion of falling tulip seeds, unlike maple seeds which autogyrate but do not tumble, or rectangular cards which tumble but do not gyrate. This coupled tumbling and autogyrating motion are robust, when card parameters, such as aspect ratio, internal angle, and mass density, are varied. We measure the three-dimensional (3D) falling kinematics of the parallelograms and quantify their descending speed, azimuthal rotation, tumbling rotation, and cone angle in each falling. The cone angle is insensitive to the variation of the card parameters, and the card tumbling axis does not overlap with but is close to the diagonal axis. In addition to this connection to the dynamics of falling seeds, these trajectories provide an ideal set of data to analyze 3D aerodynamic force and torque at an intermediate range of Reynolds numbers, and the results will be useful for constructing 3D aerodynamic force and torque models. Tracking these free falling trajectories gives us a nonintrusive method for deducing instantaneous aerodynamic forces. We determine the 3D aerodynamic forces and torques based on Newton-Euler equations. The dynamical analysis reveals that, although the angle of attack changes dramatically during tumbling, the aerodynamic forces have a weak dependence on the angle of attack. The aerodynamic lift is dominated by the coupling of translational and rotational velocities. The aerodynamic torque has an unexpectedly large component perpendicular to the card. The analysis of the Euler equation suggests that this large torque is related to the deviation of the tumbling axis from the principle axis of the card.

Short stick exercises for fall prevention among older adults: a cluster randomized trial.

PubMed

Yokoi, Katsushi; Yoshimasu, Kouichi; Takemura, Shigeki; Fukumoto, Jin; Kurasawa, Shigeki; Miyashita, Kazuhisa

2015-01-01

To investigate the effects of short stick exercise (SSEs) on fall prevention and improvement of physical function in older adults. A cluster randomized trial was conducted in five residential care facilities. The intervention group (n = 51) practiced SSEs for six months, followed by routine care for six more months. The control group (n = 54) received ordinary care for 12 months. The primary outcome measure was the number of fallers, taking into account the time to first fall using the Kaplan-Meier method. The secondary outcome measures were physical and mental functions. The number of fallers was significantly lower in the intervention group (n = 6) than in the control group (n = 16) during the 12 months. The adjusted hazard ratio for a first fall in the intervention group compared with the control group was 0.15 (CI, 0.03 to 0.74, p = 0.02). The fall-free period was significantly longer in the intervention group than in controls (mean ± SD, 10.1 ± 3.0 versus 9.0 ± 4.1 months, p = 0.027). The functional reach and sit and reach tests were significantly improved at three and six months. The SSEs appeared effective for fall prevention and improvement of physical function in older adults. Implications for Rehabilitation The newly developed short stick exercises appear an effective means of reducing falls among older adults in residential care facilities. The short stick exercises seem to have an immediate effect on improving physical functions. Effects gained by performing the short stick exercises, such as static balance, flexibility and agility may last for six months. The short stick exercises were found to be easy for older adults to practice continuously in residential care facilities.

Impairments of postural stability, core endurance, fall index and functional mobility skills in patients with patello femoral pain syndrome.

PubMed

Yilmaz Yelvar, Gul Deniz; Çirak, Yasemin; Dalkilinç, Murat; Demir, Yasemin Parlak; Baltaci, Gul; Kömürcü, Mahmut; Yelvar, Gul Deniz Yilmaz

2016-06-30

Postural control allows performance of daily and sports activities. The previous studies show that postural sway inceases in orthopaedic injuries such as osteoarthritis and total knee arthroplasty. To compare postural sway, risk of falling and function between individuals with and without patellofemoral pain syndrome (PFS). This study included 22 subjects with patellofemoral pain syndrome, age-matched pain-free 22 females serving as a control group. Visual anolog scale and Kujala were used to evaluate the pain. Posturographic assesment was performed by Tetrax posturographic device. Biering Modified Sorenson test for extensor endurance and sit-up test for flexor endurance were used for the evaluation of trunk endurance. Timed get-up and go test was used for lower extremity function. The Student's t Test was used to compare variables between the groups. The Pearson correlation coefficients were calculated to examine correlation between the quantitative variables. Postural sway included eyes open without pillow, eyes open on pillow, eyes closed on pillow, risk of falling, function and postural stabilization included flexor endurance, extansor endurance are impared in patient with patellofemoral pain syndrome when compare to controls. In subjects with PFPS increased postural sway significantly associated with body mass index (r= 0.52), pain duration (r= 0.43), postural control (extansor endurance) (r= -0.50) and risk of falling (r= 0.62) on pillow with open eyes. In addition we found function significantly related with postural control (extansor endurance and flexor endurance) (r= -0.59 and r= -0.59) and risk of falling (r= 0.77)CONCLUSIONS: Decreased neuromuscular control of the trunk core and increased postural sway and falling risk were found in patients with PFPS. Patients may be evaluated for deficits in postural control and falling risk before treatment.

Fall prevention services for older Aboriginal people: investigating availability and acceptability.

PubMed

Lukaszyk, Caroline; Coombes, Julieann; Keay, Lisa; Sherrington, Catherine; Tiedemann, Anne; Broe, Tony; Lovitt, Lorraine; Ivers, Rebecca

2016-12-14

Falls and fall-related injury are emerging issues for older Aboriginal people. Despite this, it is unknown whether older Aboriginal people access available fall prevention programs, or whether these programs are effective or acceptable to this population. To investigate the use of available fall prevention services by older Aboriginal people and identify features that are likely to contribute to program acceptability for Aboriginal communities in New South Wales (NSW), Australia. A questionnaire was distributed to Aboriginal and mainstream health and community services across NSW to identify the fall prevention and healthy ageing programs currently used by older Aboriginal people. Services with experience in providing fall prevention interventions for Aboriginal communities, and key Aboriginal health services that delivered programs specifically for older Aboriginal people, were followed up and staff members were nominated from within each service to be interviewed. Service providers offered their suggestions as to how a fall prevention program could be designed and delivered to meet the health and social needs of their older Aboriginal clients. Of the 131 services that completed the questionnaire, four services (3%) had past experience in providing a mainstream fall prevention program to Aboriginal people; however, there were no programs being offered at the time of data collection. From these four services, and from a further five key Aboriginal health services, 10 staff members experienced in working with older Aboriginal people were interviewed. Barriers preventing services from offering appropriate fall prevention programs to their older Aboriginal clients were identified, including limited funding, a lack of available Aboriginal staff, and communication difficulties between health services and sectors. According to the service providers, an effective and acceptable fall prevention intervention would be evidence based, flexible, community-oriented and social, held in a familiar and culturally safe location and delivered free of cost. This study identified a gap in the availability of acceptable fall prevention programs designed for, and delivered to, older Aboriginal people in NSW. Further consultation with older Aboriginal people is necessary to determine how an appropriate and effective program can be designed and delivered. Terminology: The authors recognise the two distinctive Indigenous populations of Australia: Aboriginal and Torres Strait Islander people. Because the vast majority of the NSW Aboriginal and Torres Strait Islander population is Aboriginal (95.4%)1, this population will be referred to as 'Aboriginal' in this manuscript.

Fall prevention by nursing assistants among community-living elderly people. A randomised controlled trial.

PubMed

Fahlström, Gunilla; Kamwendo, Kitty; Forsberg, Jenny; Bodin, Lennart

2017-08-29

Falls among elderly are a major public health issue in Sweden. The aim was to determine whether nursing assistants can prevent falls by supervising community-living elderly individuals with a history of falling in performing individually designed home exercise programmes. A randomised controlled trial was performed in Sweden, in eight municipalities in the county of Örebro, during 2007-2009. Community-living persons 65 years or older having experienced at least one fall during the last 12 months were included. The intervention group consisted of 76 participants, and there were 72 in the control group. The interventions were free of charge and were shared between a physiotherapist and a nursing assistant. The former designed a programme aiming to improve balance, leg strength and walking ability. The nursing assistant supervised the performance of activities during eight home visits during a 5-month intervention period. The measures and instruments used were health-related quality of life (SF-36), activity of daily living (ADL-staircase), balance, (Falls Efficacy Scale, and Berg Balance Scale), walking ability (Timed Up and Go and the 3-metre walking test), leg strength, (chair stand test). All participants were asked to keep a structured calendar of their physical exercise, walks and occurrence of falls during their 12-month study period. Hospital healthcare consumption data were collected. Although the 5-month intervention did not significantly decrease the risk for days with falls, RR 1.10 (95% CI 0.58, 2.07), p = 0.77, significant changes in favour of the intervention group were noted for balance (p = 0.03), ADL (p = 0.035), bodily pain (p = 0.003) and reported health transition over time (p = 0.008) as well as less hospital care due to fractures (p = 0.025). Additional studies with more participants are needed to establish whether or not falls can be significantly prevented with this model which is workable in home-based fall prevention. © 2017 Nordic College of Caring Science.

Some Static Oscillatory and Free Body Tests of Blunt Bodies at Low Subsonic Speeds

NASA Technical Reports Server (NTRS)

Lichtenstein, Jacob H.; Fisher, Lewis R.; Scher, Stanley H.; Lawrence, George F.

1959-01-01

Some blunt-body shapes considered suitable for entry into the earth's atmosphere were tested by both static and oscillatory methods in the Langley stability tunnel. In addition, free-fall tests of some similar models were made in the Langley 20-foot free-spinning tunnel. The results of the tests show that increasing the flare of the body shape increased the dynamic stability and that for flat-faced shapes increasing the corner radius increased the stability. The test data from the Langley stability tunnel were used to compute the damping factor for the models tested in the langley 20-foot free-spinning tunnel. For these cases in which the damping factor was low, -1/2 or less, the stability was critical and sensitive to disturbance. When the damping factor was about -2, damping was generally obtained.

Effect of Rotation on Scaffold Motion and Cell Growth in Rotating Bioreactors.

PubMed

Varley, Mark C; Markaki, Athina E; Brooks, Roger A

2017-06-01

Efficient use of different bioreactor designs to improve cell growth in three-dimensional scaffolds requires an understanding of their mechanism of action. To address this for rotating wall vessel bioreactors, fluid and scaffold motion were investigated experimentally at different rotation speeds and vessel fill volumes. Low cost bioreactors with single and dual axis rotation were developed to investigate the effect of these systems on human osteoblast proliferation in free floating and constrained collagen-glycosaminoglycan porous scaffolds. A range of scaffold motions (free fall, periodic oscillation, and orbital motion) were observed at the rotation speeds and vessel fluid/air ratios used, with 85% fluid fill and an outer vessel wall velocity of ∼14 mm s -1 producing a scaffold in a free fall state. The cell proliferation results showed that after 14 and 21 days of culture, this combination of fluid fill and speed of rotation produced significantly greater cell numbers in the scaffolds than when lower or higher rotation speeds (p < 0.002) or when the chamber was 60% or 100% full (p < 0.01). The fluid flow and scaffold motion experiments show that biaxial rotation would not improve the mass transfer of medium into the scaffold as the second axis of rotation can only transition the scaffold toward oscillatory or orbital motion and, hence, reduce mass transport to the scaffold. The cell culture results confirmed that there was no benefit to the second axis of rotation with no significant difference in cell proliferation either when the scaffolds were free floating or constrained (p > 0.05).

Effect of Rotation on Scaffold Motion and Cell Growth in Rotating Bioreactors

PubMed Central

Varley, Mark C.; Markaki, Athina E.

2017-01-01

Efficient use of different bioreactor designs to improve cell growth in three-dimensional scaffolds requires an understanding of their mechanism of action. To address this for rotating wall vessel bioreactors, fluid and scaffold motion were investigated experimentally at different rotation speeds and vessel fill volumes. Low cost bioreactors with single and dual axis rotation were developed to investigate the effect of these systems on human osteoblast proliferation in free floating and constrained collagen-glycosaminoglycan porous scaffolds. A range of scaffold motions (free fall, periodic oscillation, and orbital motion) were observed at the rotation speeds and vessel fluid/air ratios used, with 85% fluid fill and an outer vessel wall velocity of ∼14 mm s−1 producing a scaffold in a free fall state. The cell proliferation results showed that after 14 and 21 days of culture, this combination of fluid fill and speed of rotation produced significantly greater cell numbers in the scaffolds than when lower or higher rotation speeds (p < 0.002) or when the chamber was 60% or 100% full (p < 0.01). The fluid flow and scaffold motion experiments show that biaxial rotation would not improve the mass transfer of medium into the scaffold as the second axis of rotation can only transition the scaffold toward oscillatory or orbital motion and, hence, reduce mass transport to the scaffold. The cell culture results confirmed that there was no benefit to the second axis of rotation with no significant difference in cell proliferation either when the scaffolds were free floating or constrained (p > 0.05). PMID:28125920

Cooling and solidification of liquid-metal drops in a gaseous atmosphere

NASA Technical Reports Server (NTRS)

Mccoy, J. K.; Markworth, A. J.; Collings, E. W.; Brodkey, R. S.

1992-01-01

The free fall of a liquid-metal drop, heat transfer from the drop to its environment, and solidification of the drop are described for both gaseous and vacuum atmospheres. A simple model, in which the drop is assumed to fall rectilinearly, with behavior like that of a rigid particle, is developed to describe cooling behavior. Recalescence of supercooled drops is assumed to occur instantaneously when a specified temperature is passed. The effects of solidification and experimental parameters on drop cooling are calculated and discussed. Major results include temperature as a function of time, and of drag, time to complete solidification, and drag as a function of the fraction of the drop solidified.

Probabilistic analysis of the efficiency of the damping devices against nuclear fuel container falling

NASA Astrophysics Data System (ADS)

Králik, Juraj

2017-07-01

The paper presents the probabilistic and sensitivity analysis of the efficiency of the damping devices cover of nuclear power plant under impact of the container of nuclear fuel of type TK C30 drop. The finite element idealization of nuclear power plant structure is used in space. The steel pipe damper system is proposed for dissipation of the kinetic energy of the container free fall. The experimental results of the shock-damper basic element behavior under impact loads are presented. The Newmark integration method is used for solution of the dynamic equations. The sensitivity and probabilistic analysis of damping devices was realized in the AntHILL and ANSYS software.

The Awful Truth About Zero-Gravity: Space Acceleration Measurement System; Orbital Acceleration Research Experiment

NASA Technical Reports Server (NTRS)

2002-01-01

Earth's gravity holds the Shuttle in orbit, as it does satellites and the Moon. The apparent weightlessness experienced by astronauts and experiments on the Shuttle is a balancing act, the result of free-fall, or continuously falling around Earth. An easy way to visualize what is happening is with a thought experiment that Sir Isaac Newton did in 1686. Newton envisioned a mountain extending above Earth's atmosphere so that friction with the air would be eliminated. He imagined a cannon atop the mountain and aimed parallel to the ground. Firing the cannon propels the cannonball forward. At the same time, Earth's gravity pulls the cannonball down to the surface and eventual impact. Newton visualized using enough powder to just balance gravity so the cannonball would circle the Earth. Like the cannonball, objects orbiting Earth are in continuous free-fall, and it appears that gravity has been eliminated. Yet, that appearance is deceiving. Activities aboard the Shuttle generate a range of accelerations that have effects similar to those of gravity. The crew works and exercises. The main data relay antenna quivers 17 times per second to prevent 'stiction,' where parts stick then release with a jerk. Cooling pumps, air fans, and other systems add vibration. And traces of Earth's atmosphere, even 200 miles up, drag on the Shuttle. While imperceptible to us, these vibrations can have a profound impact on the commercial research and scientific experiments aboard the Shuttle. Measuring these forces is necessary so that researchers and scientists can see what may have affected their experiments when analyzing data. On STS-107 this service is provided by the Space Acceleration Measurement System for Free Flyers (SAMS-FF) and the Orbital Acceleration Research Experiment (OARE). Precision data from these two instruments will help scientists analyze data from their experiments and eliminate outside influences from the phenomena they are studying during the mission.

How to Make a Microgravity Drop Tower for Your Classroom

NASA Technical Reports Server (NTRS)

DeLombard, Richard; Hall, Nancy R.

2014-01-01

Microgravity is quite often seen as exotic and special as astronauts float around in the International Space Station, eating MM's in mid-air, and performing science experiments, all done seemingly without gravity being present. Surprisingly enough, up on the ISS there is about 90 of the same gravity that holds you to the floor in your classroom or museum exhibit hall. Participate in this session and you will understand that and more. You can use simple devices to demonstrate microgravity conditions in your classroom or museum exhibit hall. This will be the same microgravity condition that astronauts experience on the ISS, just for a much shorter period of time. Contrary to popular opinion of some people, microgravity is NOT caused by zero gravity up there. Microgravity on the ISS is due to free fall within the Earth's gravitational field. That means you can drop an item in free fall in your classroom and museum exhibit hall and that item will experience microgravity. In this session, a short theory segment will explain and reinforce these concepts so that you may explain to others. The session will concentrate on showing the session participants how to make an effective, but inexpensive, drop tower for use in the classroom. Such a drop tower may be used to reinforce classroom instruction in physics and forces motion as well as serve as a platform for student investigations, classroom competitions, and student science or technology fair entries. Session participants will build their own simple microgravity experiment and operate them in a drop tower, compare results, and modify their experiment based on results. This material is also useful for public demonstrations at school open houses, travelling museum exhibits, fixed museum exhibits, and independent student projects or experiments. These free fall concepts also connect terrestrial demonstrations with planetary moon motion, comet trajectory, and more.

Differences Between Gait on Stairs and Flat Surfaces in Relation to Fall Risk and Future Falls.

PubMed

Wang, Kejia; Delbaere, Kim; Brodie, Matthew A D; Lovell, Nigel H; Kark, Lauren; Lord, Stephen R; Redmond, Stephen J

2017-11-01

We used body-worn inertial sensors to quantify differences in semi-free-living gait between stairs and on normal flat ground in older adults, and investigated the utility of assessing gait on these terrains for predicting the occurrence of multiple falls. Eighty-two community-dwelling older adults wore two inertial sensors, on the lower back and the right ankle, during several bouts of walking on flat surfaces and up and down stairs, in between rests and activities of daily living. Derived from the vertical acceleration at the lower back, step rate was calculated from the signal's fundamental frequency. Step rate variability was the width of this fundamental frequency peak from the signal's power spectral density. Movement vigor was calculated at both body locations from the signal variance. Partial Spearman correlations between gait parameters and physiological fall risk factors (components from the Physiological Profile Assessment) were calculated while controlling for age and gender. Overall, anteroposterior vigor at the lower back in stair descent was lower in subjects with longer reaction times. Older adults walked more slowly on stairs, but they were not significantly slower on flat surfaces. Using logistic regression, faster step rate in stair descent was associated with multiple prospective falls over 12 months. No significant associations were shown from gait parameters derived during walking upstairs or on flat surfaces. These results suggest that stair descent gait may provide more insight into fall risk than regular walking and stair ascent, and that further sensor-based investigation into unsupervised gait on different terrains would be valuable.

Conditioning of sandhill cranes during fall migration

USGS Publications Warehouse

Krapu, Gary L.; Johnson, Douglas H.

1990-01-01

Body mass of adult female and male sandhill cranes (Grus canadensis) increased an average of 17 and 20%, respectively, from early September to late October on staging areas in central North Dakota and varied by year. Increases in body mass averaged 550 and 681 g among female and male G. c. canadensis, respectively, and 616 and 836 g among female and male G. c. rowani. Adult and juvenile G. c. rowani were lean at arrival, averaging 177 and 83 g of fat, respectively, and fat reserves increased to 677 and 482 g by mid-October. Fat-free dry mass increased by 12% among juveniles, reflecting substantial growth, but remained constant among adults. The importance of fall staging areas as conditioning sites for sandhill cranes, annual variation in body mass, and vulnerability of cranes to habitat loss underscore the need to monitor status of fall staging habitat in the northern plains region and to take steps to maintain suitable habitat where necessary.

[Positional asphyxia--death in a head-down position after falling down stairs].

PubMed

Doberentz, Elke; Madea, Burkhard

2012-01-01

The discovery of a body in an unusual position such as a head-down position requires thorough investigation. In this article, such a death is reported. A 64-year-old man was found in a head-down position at the bottom of a narrow staircase after obviously falling down the stairs. His head was wedged between the last step and a closed sliding door. Autopsy revealed craniofacial blunt force injuries, a non-dislocated fracture of the 4th cervical vertebral body (with intact ligaments of the spine and cervical cord) and massive cerebral and pulmonary oedema. Although the heart was significantly enlarged (610 g), the coronary arteries showed only minor arteriosclerotic changes. The alcohol concentration measured was 2.06 per mil in blood and 2.67 per mil in urine. The alcohol intoxication increased the risk to fall and together with the trauma of the cervical spine made it impossible for the man to free himself so that he ultimately died in a head-down position.

Leidenfrost vapour layer moderation of the drag crisis and trajectories of superhydrophobic and hydrophilic spheres falling in water.

PubMed

Vakarelski, Ivan U; Chan, Derek Y C; Thoroddsen, Sigurdur T

2014-08-21

We investigate the dynamic effects of a Leidenfrost vapour layer sustained on the surface of heated steel spheres during free fall in water. We find that a stable vapour layer sustained on the textured superhydrophobic surface of spheres falling through 95 °C water can reduce the hydrodynamic drag by up to 75% and stabilize the sphere trajectory for the Reynolds number between 10(4) and 10(6), spanning the drag crisis in the absence of the vapour layer. For hydrophilic spheres under the same conditions, the transition to drag reduction and trajectory stability occurs abruptly at a temperature different from the static Leidenfrost point. The observed drag reduction effects are attributed to the disruption of the viscous boundary layer by the vapour layer whose thickness depends on the water temperature. Both the drag reduction and the trajectory stabilization effects are expected to have significant implications for development of sustainable vapour layer based technologies.

Estimating Volume of Roof Fall in the Face of Longwall Mining by Using Numerical Methods / Estymacja Objętości Zawału Stropu W Rejonie Przodka Ścianowego W Oparciu O Metody Numeryczne

NASA Astrophysics Data System (ADS)

Saeedi, Gholamreza; Shahriar, Korosh; Rezai, Bahram

2013-09-01

Dilution is one of many challenges confronting professionals in mining and milling, and is perhaps one of the oldest. Longwall mining is one of the mining methods that is often affected by out-of-seam dilution (OSD). In this method, roof falls play a significant role in increasing OSD in the prop-free front of the face area. Thus, estimating the volume of roof fall can be extremely helpful to assess dilution of the run of mine coal without a sampling process. This paper presents the effect of exposed area geometry on potential roof falls using the 2D numerical modelling program FLAC. In this respect, a half-prolate ellipsoid was considered as the low stress level or plasticity zone under yield tension which roof material fall. Since FLAC software does not show roof falls in prop-free front of the face, a series of two-dimensional numerical models are developed using UDEC software. The comparison of the results of two numerical models clearly indicates that volumes of roof fall obtained by means of these methods are in good agreement with each other. Ścienianie warstw jest jednym z najpoważniejszych wyzwań stojących przed inżynierami górnikami i specjalistami z zakresu obróbki - jest to też jeden z najstarszych problemów. Wybieranie ścianowe jest metodą urabiania, w której często mamy do czynienia ze ścienianiem warstwy złoża. W metodzie tej strop odgrywa kluczową rolę w zapewnieniu stabilności w tych rejonach przodka, gdzie nie zastosowano obudów. Dlatego też estymacja objętości zawału stropu może być pomocna przy obliczaniu ścieniania warstwy węgla bez konieczności próbkowania. W artykule tym przeanalizowano wpływ geometrii powierzchni odkrytych na potencjalny zawał stropu przy użyciu metod modelowania numerycznego z wykorzystaniem oprogramowania FLAC. Uzyskano wydłużoną elipsoidę jako model strefy niskich naprężeń lub strefę plastyczności przed zawałem stropu. Ponieważ oprogramowanie FLAC nie pokazuje zawałów stropu w strefie przodka, gdzie nie ma obudów, opracowano serię dwuwymiarowych modeli numerycznych, z wykorzystaniem oprogramowania UDEC. Porównanie wyników uzyskanych przy zastosowaniu obydwu modeli numerycznych wykazało, że objętości materiału stropu po zawale obliczone za pomocą tych dwóch metod wykazują dużą zgodność.

Amid Free College Proposals, a Guarantee from New Hampshire

ERIC Educational Resources Information Center

D'Allesandro, Lou

2017-01-01

The dream of an accessible education will now become a reality for many New Hampshire youngsters, thanks to a new University of New Hampshire (UNH) initiative called the Granite Guarantee Program. The UNH Granite Guarantee will begin with the incoming freshman class in fall 2017. An estimated 400 New Hampshire students will benefit from the…

Enhancement of Fusarium Head Blight Detection in Free-Falling Wheat Kernels Using a Bichromatic Pulsed LED Design

USDA-ARS?s Scientific Manuscript database

Fusarium Head Blight is a worldwide disease of small cereals grains such as wheat. The disease is food safety concern because it produces the metabolite, deoxynivalenol (DON), which is moderately toxic to humans and non-ruminant animals. The current study was implemented to develop more efficient me...

Can a Road-Driven Car Outrace a Free-Falling Car?

ERIC Educational Resources Information Center

Castano, Diego J.

2011-01-01

Although nowadays there are mythbusting teams ready to empirically confirm or deny advertising claims that may seem too good to be true, it is often economically prohibitive to perform the kinds of experiments that are called for. It is therefore sometimes more sensible and efficacious to perform a thought experiment instead, especially if the…

Steps toward Learning Mechanics Using Fan Cart Video Demonstrations

ERIC Educational Resources Information Center

Lattery, Mark

2011-01-01

The Newtonian force concept is very difficult for introductory students to learn. One obstacle to learning is a premature focus on gravity-driven motions, such as vertical free fall, rolling motion on an inclined plane, and the Atwood's machine. In each case, the main agent of motion ("gravity") cannot be seen, heard, or controlled by the student.…

Increasing of horizontal velocity of particles leaving a belt conveyor

NASA Astrophysics Data System (ADS)

Tavares, Abraão; Faria, Allbens

2017-06-01

We investigate the transport of granular materials by a conveyor belt via numerical simulations. We report an unusual increasing of particles horizontal velocity when they leave the belt and initiate free-fall. Using Discrete Elements Method, the mechanism underlying this phenomenon were investigated, and a study on how particle and system properties influences this effect were conducted.

Born Free but in Chains: Academic Freedom and Rights of Governance

ERIC Educational Resources Information Center

Academe, 2005

2005-01-01

This article presents the address delivered by Roger Bowen, American Association of University Professors' (AAUP) general secretary, last fall to the Coalition of Faculty Associations of Western New York. The AAUP's history could be rendered in a series of biographies about academic dissenters who dared to speak truth to power. His address centers…

Supersonic Jump

ERIC Educational Resources Information Center

Muller, Andreas

2013-01-01

On October 14,2012, Felix Baumgartner, an Austrian sky-diver, set some new world records for his discipline. Jumping from a height of about 39 km, he reached a top speed of 1342 km/h, becoming the first human being to break the sound barrier in free fall. In order to understand some essential physics aspects of this remarkable feat, we wonder why…

Learning Curve: Adapting Library Workspaces

ERIC Educational Resources Information Center

Haug, James C.

2008-01-01

One of the hubs of campus life at Longwood University--located in the small central Virginia town of Farmville--is the Janet D. Greenwood Library. In fall 2004, reference materials were relocated to free up space, and 15 computer workstations, which had been lined up against a wall, were replaced with 48 new PCs. In 2005, library staff began…

Texas Educators Seek Clarification on "Hopwood" Decision: Minority Admission to Texas Elite Public Colleges in Free-Fall.

ERIC Educational Resources Information Center

Richardson, Susan

1997-01-01

As Texas' elite public colleges and universities experience enrollment declines, the state is requesting clarification of the legal decision in "Hopwood v. Texas," in which the court rejected affirmative action and mandated race-neutral admissions policies. The Texas attorney general disagrees with federal officials and critics on…

Moving Phones Tick Slower: Creating an Android App to Demonstrate Time Dilation

ERIC Educational Resources Information Center

Underwood, Bret; Zhai, Yunxiao

2016-01-01

Smartphones and tablets are packed with sensors that allow us to take experimental data, essentially making them mobile physics labs. Apps exist that make it easy to capture and analyze data from these sensors, allowing users to study diverse phenomena such as free fall acceleration, the speed of sound,radioactivity, and many others. Commonly, the…

A Demonstration of Einstein's Equivalence of Gravity and Acceleration

ERIC Educational Resources Information Center

Newburgh, Ronald

2008-01-01

In 1907, Einstein described a "Gedankenexperiment" in which he showed that free fall in a gravitational field is indistinguishable from a body at rest in an elevator accelerated upwards in zero gravity. This paper describes an apparatus, which is simple to make and simple to operate, that acts as an observable footnote to Einstein's example. It…

Representing and Meaning in History and in Classrooms: Developing Symbols and Conceptual Organizations of Free-Fall Motion.

ERIC Educational Resources Information Center

Ford, Michael J.

2003-01-01

Offers a psychological role that external representations can play in the process of refining intuitive ideas into scientific knowledge. Presents an argument for this role through historical analysis of Galileo's ramp experiments, then through documentation of an innovative 6th grade classroom activity. (Contains 19 references.) (Author/YDS)

30 CFR 18.66 - Tests of windows and lenses.

Code of Federal Regulations, 2010 CFR

2010-07-01

... 30 Mineral Resources 1 2010-07-01 2010-07-01 false Tests of windows and lenses. 18.66 Section 18... Tests § 18.66 Tests of windows and lenses. (a) Impact tests. A 4-pound cylindrical weight with a 1-inch-diameter hemispherical striking surface shall be dropped (free fall) to strike the window or lens in its...

Strategic Leader Development for a 21st Century Army

DTIC Science & Technology

2008-04-30

Fall of Strategic Planning. New York, NY: The Free Press, 1994. Northouse , Peter G. Leadership : Theory and Practice. Thousand Oaks, CA: Sage...TERMS Strategic Leadership ; Strategic Thinking; Contemporary Operational Environment; Adaptability; Self Awareness; Complexity; Officer Education...managing today’s fluid operational environment. The concept of strategic leadership , therefore, must be examined closely in Army doctrine. Social

Measurement of "g" Using a Magnetic Pendulum and a Smartphone Magnetometer

ERIC Educational Resources Information Center

Pili, Unofre; Violanda, Renante; Ceniza, Claude

2018-01-01

The internal sensors in smartphones for their advanced add-in functions have also paved the way for these gadgets becoming multifunctional tools in elementary experimental physics. For instance, the acceleration sensor has been used to analyze free-falling motion and to study the oscillations of a spring-mass system. The ambient light sensor on…

Videos Determine the Moon's "g"

ERIC Educational Resources Information Center

Persson, J. R.; Hagen, J. E.

2011-01-01

Determining the acceleration of a free-falling object due to gravity is a standard experiment in physics. Different methods to do this have been developed over the years. This article discusses the use of video-analysis tools as another method. If there is a video available and a known scale it is possible to analyse the motion. The use of video…

Growing spearmint, thyme, oregano, and rosemary in Northern Wyoming using plastic tunnels

USDA-ARS?s Scientific Manuscript database

Growing perennial herbs in northern climate such as Northern Wyoming is a challenge. Due to short frost-free period, high wind, and inclement weather it is impossible to harvest any herbs twice a year (summer and late fall) without using any form of season extension methods. Hence, we set up an expe...

The role of randomized cluster crossover trials for comparative effectiveness testing in anesthesia: design of the Benzodiazepine-Free Cardiac Anesthesia for Reduction in Postoperative Delirium (B-Free) trial.

PubMed

Spence, Jessica; Belley-Côté, Emilie; Lee, Shun Fu; Bangdiwala, Shrikant; Whitlock, Richard; LeManach, Yannick; Syed, Summer; Lamy, Andre; Jacobsohn, Eric; MacIsaac, Sarah; Devereaux, P J; Connolly, Stuart

2018-07-01

Increasingly, clinicians and researchers recognize that studies of interventions need to evaluate not only their therapeutic efficacy (i.e., the effect on an outcome in ideal, controlled settings) but also their real-world effectiveness in broad, unselected patient groups. Effectiveness trials inform clinical practice by comparing variations in therapeutic approaches that fall within the standard of care. In this article, we discuss the need for studies of comparative effectiveness in anesthesia and the limitations of individual patient randomized-controlled trials in determining comparative effectiveness. We introduce the concept of randomized cluster crossover trials as a means of answering questions of comparative effectiveness in anesthesia, using the design of the Benzodiazepine-Free Cardiac Anesthesia for Reduction in Postoperative Delirium (B-Free) trial (Clinicaltrials.gov identifier NCT03053869).

Development of a Free-Flight Simulation Infrastructure

NASA Technical Reports Server (NTRS)

Miles, Eric S.; Wing, David J.; Davis, Paul C.

1999-01-01

In anticipation of a projected rise in demand for air transportation, NASA and the FAA are researching new air-traffic-management (ATM) concepts that fall under the paradigm known broadly as ":free flight". This paper documents the software development and engineering efforts in progress by Seagull Technology, to develop a free-flight simulation (FFSIM) that is intended to help NASA researchers test mature-state concepts for free flight, otherwise referred to in this paper as distributed air / ground traffic management (DAG TM). Under development is a distributed, human-in-the-loop simulation tool that is comprehensive in its consideration of current and envisioned communication, navigation and surveillance (CNS) components, and will allow evaluation of critical air and ground traffic management technologies from an overall systems perspective. The FFSIM infrastructure is designed to incorporate all three major components of the ATM triad: aircraft flight decks, air traffic control (ATC), and (eventually) airline operational control (AOC) centers.

Experimental limit on the ratio of the gravitational mass to the inertial mass of antihydrogen

NASA Astrophysics Data System (ADS)

Fajans, Joel; Wurtele, Jonathan; Charman, Andrew; Zhmoginov, Andrey

2012-10-01

Physicists have long wondered if the gravitational interactions between matter and antimatter might be different from those between matter and itself. While there are many indirect indications that no such differences exist, i.e., that the weak equivalence principle holds, there have been no direct, free-fall style, experimental tests of gravity on antimatter. By searching for a propensity for antihydrogen atoms to fall downward when released from the ALPHA antihydrogen trap, we have determined that we can reject ratios of the gravitational mass to the inertial mass of antihydrogen greater than about 100 at a statistical significance level of 5%. A similar search places somewhat lower limits on a negative gravitational mass, i.e., on antigravity.

MICROSCOPE Mission: First Results of a Space Test of the Equivalence Principle.

PubMed

Touboul, Pierre; Métris, Gilles; Rodrigues, Manuel; André, Yves; Baghi, Quentin; Bergé, Joël; Boulanger, Damien; Bremer, Stefanie; Carle, Patrice; Chhun, Ratana; Christophe, Bruno; Cipolla, Valerio; Damour, Thibault; Danto, Pascale; Dittus, Hansjoerg; Fayet, Pierre; Foulon, Bernard; Gageant, Claude; Guidotti, Pierre-Yves; Hagedorn, Daniel; Hardy, Emilie; Huynh, Phuong-Anh; Inchauspe, Henri; Kayser, Patrick; Lala, Stéphanie; Lämmerzahl, Claus; Lebat, Vincent; Leseur, Pierre; Liorzou, Françoise; List, Meike; Löffler, Frank; Panet, Isabelle; Pouilloux, Benjamin; Prieur, Pascal; Rebray, Alexandre; Reynaud, Serge; Rievers, Benny; Robert, Alain; Selig, Hanns; Serron, Laura; Sumner, Timothy; Tanguy, Nicolas; Visser, Pieter

2017-12-08

According to the weak equivalence principle, all bodies should fall at the same rate in a gravitational field. The MICROSCOPE satellite, launched in April 2016, aims to test its validity at the 10^{-15} precision level, by measuring the force required to maintain two test masses (of titanium and platinum alloys) exactly in the same orbit. A nonvanishing result would correspond to a violation of the equivalence principle, or to the discovery of a new long-range force. Analysis of the first data gives δ(Ti,Pt)=[-1±9(stat)±9(syst)]×10^{-15} (1σ statistical uncertainty) for the titanium-platinum Eötvös parameter characterizing the relative difference in their free-fall accelerations.

MICROSCOPE Mission: First Results of a Space Test of the Equivalence Principle

NASA Astrophysics Data System (ADS)

Touboul, Pierre; Métris, Gilles; Rodrigues, Manuel; André, Yves; Baghi, Quentin; Bergé, Joël; Boulanger, Damien; Bremer, Stefanie; Carle, Patrice; Chhun, Ratana; Christophe, Bruno; Cipolla, Valerio; Damour, Thibault; Danto, Pascale; Dittus, Hansjoerg; Fayet, Pierre; Foulon, Bernard; Gageant, Claude; Guidotti, Pierre-Yves; Hagedorn, Daniel; Hardy, Emilie; Huynh, Phuong-Anh; Inchauspe, Henri; Kayser, Patrick; Lala, Stéphanie; Lämmerzahl, Claus; Lebat, Vincent; Leseur, Pierre; Liorzou, Françoise; List, Meike; Löffler, Frank; Panet, Isabelle; Pouilloux, Benjamin; Prieur, Pascal; Rebray, Alexandre; Reynaud, Serge; Rievers, Benny; Robert, Alain; Selig, Hanns; Serron, Laura; Sumner, Timothy; Tanguy, Nicolas; Visser, Pieter

2017-12-01

According to the weak equivalence principle, all bodies should fall at the same rate in a gravitational field. The MICROSCOPE satellite, launched in April 2016, aims to test its validity at the 10-15 precision level, by measuring the force required to maintain two test masses (of titanium and platinum alloys) exactly in the same orbit. A nonvanishing result would correspond to a violation of the equivalence principle, or to the discovery of a new long-range force. Analysis of the first data gives δ (Ti ,Pt )=[-1 ±9 (stat)±9 (syst)]×10-15 (1 σ statistical uncertainty) for the titanium-platinum Eötvös parameter characterizing the relative difference in their free-fall accelerations.

Water velocity, turbulence, and migration rate of subyearling fall Chinook salmon in the free-flowing and impounded Snake River

USGS Publications Warehouse

Tiffan, Kenneth F.; Kock, Tobias J.; Haskell, Craig A.; Connor, William P.; Steinhorst, R. Kirk

2009-01-01

We studied the migratory behavior of subyearling fall Chinook salmon Oncorhynchus tshawytscha in free-flowing and impounded reaches of the Snake River to evaluate the hypothesis that velocity and turbulence are the primary causal mechanisms of downstream migration. The hypothesis states that impoundment reduces velocity and turbulence and alters the migratory behavior of juvenile Chinook salmon as a result of their reduced perception of these cues. At a constant flow (m3 /s), both velocity (km/d) and turbulence (the SD of velocity) decreased from riverine to impounded habitat as cross-sectional areas increased. We found evidence for the hypothesis that subyearling Chinook salmon perceive velocity and turbulence cues and respond to these cues by varying their behavior. The percentage of the subyearlings that moved faster than the average current speed decreased as fish made the transition from riverine reaches with high velocities and turbulence to upper reservoir reaches with low velocities and turbulence but increased to riverine levels again as the fish moved further down in the reservoir, where velocity and turbulence remained low. The migration rate (km/d) decreased in accordance with longitudinal reductions in velocity and turbulence, as predicted by the hypothesis. The variation in migration rate was better explained by a repeatedmeasures regression model containing velocity (Akaike’s information criterion ¼ 1,769.0) than a model containing flow (2,232.6). We conclude that subyearling fall Chinook salmon respond to changes in water velocity and turbulence, which work together to affect the migration rate.

Measurement of g Using a Flashing LED

NASA Astrophysics Data System (ADS)

Terzella, T.; Sundermier, J.; Sinacore, J.; Owen, C.; Takai, H.

2008-10-01

In one of the classic free-fall experiments, a small mass is attached to a strip of paper tape and both are allowed to fall through a spark timer, where sparks are generated at regular time intervals. Students analyze marks (dots) left on the tape by the timer, thereby generating distance-versus-time data, which they analyze to extract the acceleration due to gravity g with good results. The apparatus, however, is cumbersome and often frustrating for students. High-tech versions of this experiment are done with an object dropped and followed by a motion sensor connected to a computer. The sensor relies on ultrasonic ranging to record distance and time data, which may then be displayed graphically. Students inspect the graphs to determine the value of g. Although the results are excellent, the emphasis on the computer's ability to collect and analyze data leaves little analysis for the students to perform.2 Furthermore, neither technique gives an intuitive display of what is happening. The motivation for our work was to overcome these issues by developing an innovative method for measuring g. In our version of the experiment, students drop a flashing LED at a known frequency and record its trajectory using long exposure photography with a digital camera. Proper choice of flashing LED timing parameters produces an image that allows for an accurate measurement of g and at the same time helps to explain what happens during free fall. The experiment remains high-tech in the sense that students learn to use updated equipment to record data and to carry out the analysis.

Effect of Modified Otago Exercises on Postural Balance, Fear of Falling, and Fall Risk in Older Fallers With Knee Osteoarthritis and Impaired Gait and Balance: A Secondary Analysis.

PubMed

Mat, Sumaiyah; Ng, Chin Teck; Tan, Pey June; Ramli, Norlisah; Fadzli, Farhana; Rozalli, Faizatul Izza; Mazlan, Mazlina; Hill, Keith D; Tan, Maw Pin

2018-03-01

Osteoarthritis (OA) is considered an established risk factor for falls. Published studies evaluating secondary falls prevention strategies among individuals with OA are limited. To evaluate the effect of a personalized home-based exercise program to improve postural balance, fear of falling, and falls risk in older fallers with knee OA and gait and balance problems. Randomized controlled trial. University of Malaya Medical Centre. Fallers who had both radiological OA and a Timed Up and Go (TUG) score of over 13.5 seconds. Postural sway (composite sway) was quantified with the Modified Clinical Test of Sensory Interaction on Balance (mCTSIB) under 4 different sensory conditions: eyes open on firm surface, eyes closed on firm surface, eyes open on unstable foam surface, and eyes closed on unstable foam surface. Participants were asked to stand upright and to attempt to hold their position for 10 seconds for each test condition. The average reading for all conditions were calculated. Participants randomized to the intervention arm received a home-based modified Otago Exercise Program (OEP) as part of a multifactorial intervention, whereas control participants received general health advice and conventional treatment. This was a secondary subgroup analysis from an original randomized controlled trial, the Malaysian Falls Assessment and Intervention Trial (MyFAIT) (trial registration number: ISRCTN11674947). Posturography using a long force plate balance platform (Balancemaster, NeuroCom, USA), the Knee injury and Osteoarthritis Outcome Score (KOOS) and the short-form Falls Efficacy Scale-International (short FES-I) were assessed at baseline and 6 months. Results of 41 fallers with radiological evidence of OA and impaired TUG (intervention, 17; control, 24) were available for the final analysis. Between-group analysis revealed significant improvements in the Modified Clinical Test of Sensory Interaction on Balance (mCTSIB), Limits of Stability (LOS), and short FES-I scores by the intervention group compared to the control group at 6 months. No significant difference in time to first fall or in fall-free survival between the intervention and control groups was found. Home-based balance and strength exercises benefited older fallers with OA and gait and balance disorders by improving postural control, with no observable trend in reduction of fall recurrence. Our findings will now inform a future, adequately powered, randomized controlled study using fall events as definitive outcomes. I. Copyright © 2018 American Academy of Physical Medicine and Rehabilitation. Published by Elsevier Inc. All rights reserved.

Nuclear technology requires free elections

NASA Astrophysics Data System (ADS)

Synek, Miroslav

1999-10-01

The historical development on our planet has reached a powerful technology of nuclear intercontinental ballistic missiles, conceivably controllable through a computerized ``push-button." If this technology ever falls under the control of an irresponsible, miscalculating, or insane DICTATOR, with powerful means of a mass-produced nuclear built-up, anywhere on our planet, the very SURVIVAL OF ALL HUMANITY on our planet could be threatened. Therefore, it is a historical urgency that this technology is under the control by the people, through a sufficiently secure system of FREE ELECTIONS, in any country, wherever and whenever such a threatening possibility exists. Of course, a starting system of FREE ELECTIONS, even if quite rudimentary, should try to provide for its continuous functioning, with an underlying appropriate freedom of expression and with rules for its continuation, while aiming towards continuous improvements.

Lipolytic and oxidative changes in 'Chorizo' during ripening.

PubMed

Fernández, M C; Rodríguez, J M

1991-01-01

Changes in fats during the ripening of 'chorizo'-a Spanish dry sausage- elaborated by traditional and industrial processes have been studied. Total free fatty acids (FFA), carbonyls, volatile fatty acids (acetic acid), TBA number and individual FFA were determined. A marked increase of total free fatty acids was observed, although an increase of rancidity was not detected. Except in one of the batches studied in which a rise in carbonyls was reported, these compounds remained unchanged during the ripening in the rest of the batches analysed. No significant change occurred in the proportions of different free fatty acids during ripening in both types of 'chorizo'. There was a marked increase of acetic acid during the first days of ripening followed by a slow fall in the ultimate stages. Copyright © 1990. Published by Elsevier Ltd.

Hadronic Form Factors in Asymptotically Free Field Theories

DOE R&D Accomplishments Database

Gross, D. J.; Treiman, S. B.

1974-01-01

The breakdown of Bjorken scaling in asymptotically free gauge theories of the strong interactions is explored for its implications on the large q{sup 2} behavior of nucleon form factors. Duality arguments of Bloom and Gilman suggest a connection between the form factors and the threshold properties of the deep inelastic structure functions. The latter are addressed directly in an analysis of asymptotically free theories; and through the duality connection we are then led to statements about the form factors. For very large q{sup 2} the form factors are predicted to fall faster than any inverse power of q{sup 2}. For the more modest range of q{sup 2} reached in existing experiments the agreement with data is fairly good, though this may well be fortuitous. Extrapolations beyond this range are presented.

Flying Through Polytropes

NASA Technical Reports Server (NTRS)

Pesnell, W. Dean

2016-01-01

Dropping objects into a tunnel bored through Earth has been used to visualize simple harmonic motion for many years, and even imagined for use as rapid transport systems. Unlike previous studies that assumed a constant density Earth, here we calculate the fall-through time of polytropes, models of Earth's interior where the pressure varies as a power of the density. This means the fall-through time can be calculated as the central condensation varies from one to large within the family of polytropes. Having a family of models, rather than a single model, helps to explore the properties of planets and stars. Comparing the family of phase space solutions shows that the fall-through time and velocity approach the limit of radial free-fall onto a point mass as the central condensation increases. More condensed models give higher maximum velocities but do not have the right global properties for Earth. The angular distance one can travel along the surface is calculated as a brachistochrone (path of least time) tunnel that is a function of the depth to which the tunnel is bored. We also show that completely degenerate objects, simple models of white dwarf stars supported by completely degenerate electrons, have sizes similar to Earth but their much higher masses mean a much larger gravitational strength and a shorter fall-through time. Numerical integrations of the equations describing polytropes and completely degenerate objects are used to generate the initial models. Analytic solutions and numerical integration of the equations of motion are used to calculate the fall-through time for each model, and numerical integrations with analytic approximations at the boundaries are used to calculate the brachistochrones in the polytropes. Scaling relationships are provided to help use these results in other planets and stars.

Production of continuous glass fiber using lunar simulant

NASA Technical Reports Server (NTRS)

Tucker, Dennis S.; Ethridge, Edwin C.; Curreri, Peter A.

1991-01-01

The processing parameters and mechanical properties of glass fibers pulled from simulated lunar basalt are tested. The simulant was prepared using a plasma technique. The composition is representative of a low titanium mare basalt (Apollo sample 10084). Lunar gravity experiments are to be performed utilizing parabolic aircraft free-fall maneuvers which yield 30 seconds of 1/6-g per maneuver.

A Measurement of "g" Using Alexander's Diving Bell

ERIC Educational Resources Information Center

Quiroga, M.; Martinez, S.; Otranto, S.

2010-01-01

This paper describes a very simple exercise using an inverted test tube pushed straight down into a column of water to determine the free-fall acceleration "g". The exercise employs the ideal gas law and only involves the measurement of the displacement of the bottom of the "diving bell" and the water level inside the tube with respect to the…

Alcohol and Other Drug Prevention: An Overview for Educators: A Description of the Implementation of a Model Course Outline.

ERIC Educational Resources Information Center

Berliner, BethAnn

In the fall of 1991, the Western Regional Center for Drug-Free Schools and communities published "Alcohol and Other Drug Prevention: An Overview for Educators." This model course outline was designed to assist institutes of higher education in offering preservice and continuing education courses for teachers and other educational…

The GBAR experiment: gravitational behaviour of antihydrogen at rest

NASA Astrophysics Data System (ADS)

Perez, P.; Sacquin, Y.

2012-09-01

The recently recommended experiment GBAR is foreseen to run at CERN at the AD/ELENA antiproton source. It aims at performing the first measurement of the Earth's gravitational acceleration on antimatter by observing the free-fall of antihydrogen atoms. This requires creating anti-atoms at an unprecedented low energy. The different steps of the experiment and their present status are reviewed.

49 CFR 178.609 - Test requirements for packagings for infectious substances.

Code of Federal Regulations, 2011 CFR

2011-10-01

... free-fall drops onto a rigid, nonresilient, flat, horizontal surface from a height of 9 m (30 feet... must be dropped, one in each of the following orientation: (i) Flat on the base; (ii) Flat on the top; (iii) Flat on the longest side; (iv) Flat on the shortest side; and (v) On a corner. (2) Where the...

Analyzing free fall with a smartphone acceleration sensor

NASA Astrophysics Data System (ADS)

Wogt, Patrik; Kuhn, Jochen

2012-03-01

This paper provides a first example of experiments in this column using smartphones as experimental tools. More examples concerning this special tool will follow in the next issues. The differences between a smartphone and a ``regular'' cell phone are that smartphones offer more advanced computing ability and connectivity. Smartphones combine the functions of personal digital assistants (PDAs) and cell phones.

Preventing Unplanned Pregnancy and Completing College: An Evaluation of Online Lessons. 2nd Edition

ERIC Educational Resources Information Center

Antonishak, Jill; Connolly, Chelsey

2014-01-01

The National Campaign to Prevent Teen and Unplanned Pregnancy published free online lessons that help students take action to prevent unplanned pregnancy and complete their education. From the fall of 2012 to the spring of 2014, approximately 2,800 students took the online lessons and participated in pre- and post-lesson evaluation surveys at four…

Robotics Strategy White Paper

DTIC Science & Technology

2009-03-19

Cargo packaging and pallet assembly. Use of robotics tools to support palletization falls under the supply functional area which tasks the Army to...system. 17 At first glance, remote tele-operated surgery capability appears to already exist in civilian hospitals (i.e., DaVinci Machine: http... tool free maintenance and anticipatory sustainment and improved distribution. The UJTL tasks suggest nominal improvements in the maintenance area

Free Tax Assistance and the Earned Income Tax Credit: Vital Resources for Social Workers and Low-Income Families

ERIC Educational Resources Information Center

Lim, Younghee; DeJohn, Tara V.; Murray, Drew

2012-01-01

As the United States' economy continues to experience challenges, more families at or near the poverty level fall prey to predatory financial practices. Their vulnerability to these operations is increased by a lack of knowledge of asset-building resources and alternative financial services. This article focuses on Volunteer Income Tax Assistance…

75 FR 64507 - Taking and Importing Marine Mammals; Military Training Activities Conducted Within the Gulf of...

Federal Register 2010, 2011, 2012, 2013, 2014

2010-10-19

... the typical ordnance that may be used in a SINKEX, which may include missiles, bombs, 5'' gunfire, and...)--During an air-to-surface BOMBEX, maritime patrol aircraft (MPA) or F/A-18 deliver free-fall bombs against... ft (914 m) while adhering to designated ingress and egress routes. Typical bomb release altitude is...

The Rise and Fall of Supplemental Educational Services: Policy Implications for Government Markets

ERIC Educational Resources Information Center

Mesecar, Doug

2015-01-01

Free after-school tutoring, known as supplemental educational services (SES), was brought to life by the No Child Left Behind Act (NCLB) in 2002. SES was designed to provide extra academic assistance to low-income students in schools failing to make accountability targets. SES is a cautionary tale, for there has never been an experiment like it in…

Assessment of Change in Conservation Attitudes through Zoo Education

ERIC Educational Resources Information Center

Randall, Teresa

2011-01-01

This study was conducted at the Oklahoma City Zoo in fall 2010 and subjects were students' ages 14-18 who either participated in a formal conservation education class led by zoo educators or in a field trip in which they were engaged in free-choice learning. Two research questions were: 1) Does a trip to the zoo affect conservation attitudes and…

Revealing physical education students’ misconception in sport biomechanics

NASA Astrophysics Data System (ADS)

Kartiko, D. C.

2018-04-01

The aim of this research is reveal Physical Education students’ misconception in several concepts of Sport Biomechanics. The Data of misconception collected by standard question of Diagnostic Test that given to 30 students of Physical Education, Faculty of Sport, State University of Surabaya in academic year 2017/2018. Diagnostic Test completed with CRI (Certainty of Response Index) in order to collect data of students’ certain in answered test. The data result of diagnostic test analysed through compilation graph of CRI right, CRI wrong and right fraction in every single question. Furthermore, students’ answer result of diagnostic test categorized in to 4 quadrants, these: correct concepts, lucky guess, misconceptions, and lack of knowledge. Its categorizing data to know percentage of misconceptions that arise in every concept tested. These sport biomechanics concepts tested are limited on frictional force, deference of distance and displacement, deference of velocity and acceleration, and free fall motion. The result obtained arise misconception in frictional force 52,78%; deference of distance and displacement 36,67%; deference of velocity and acceleration 56,67%; and free fall motion 53,33%. Result of t-test in diagnostic test misconception percentage showed that percentage of misconception arises in every student above 50%.

Parachuting from fixed objects: descriptive study of 106 fatal events in BASE jumping 1981-2006.

PubMed

Westman, A; Rosén, M; Berggren, P; Björnstig, U

2008-06-01

To analyse the characteristics of fatal incidents in fixed object sport parachuting (building, antenna, span, earth (BASE) jumping) and create a basis for prevention. Descriptive epidemiological study. Data on reported fatal injury events (n = 106) worldwide in 1981-2006 retrieved from the BASE fatality list. Human, equipment and environmental factors. Identification of typical fatal incident and injury mechanisms for each of the four fixed object types of BASE jumping (building, antenna, span, earth). Human factors included parachutist free fall instability (loss of body control before parachute deployment), free fall acrobatics and deployment failure by the parachutist. Equipment factors included pilot chute malfunction and parachute malfunction. In cliff jumping (BASE object type E), parachute opening towards the object jumped was the most frequent equipment factor. Environmental factors included poor visibility, strong or turbulent winds, cold and water. The overall annual fatality risk for all object types during the year 2002 was estimated at about one fatality per 60 participants. Participants in BASE jumping should target risk factors with training and technical interventions. The mechanisms described in this study should be used by rescue units to improve the management of incidents.

Formation and evolution of coronal rain observed by SDO/AIA on February 22, 2012

NASA Astrophysics Data System (ADS)

Vashalomidze, Z.; Kukhianidze, V.; Zaqarashvili, T. V.; Oliver, R.; Shergelashvili, B.; Ramishvili, G.; Poedts, S.; De Causmaecker, P.

2015-05-01

Context. The formation and dynamics of coronal rain are currently not fully understood. Coronal rain is the fall of cool and dense blobs formed by thermal instability in the solar corona towards the solar surface with acceleration smaller than gravitational free fall. Aims: We aim to study the observational evidence of the formation of coronal rain and to trace the detailed dynamics of individual blobs. Methods: We used time series of the 171 Å and 304 Å spectral lines obtained by the Atmospheric Imaging Assembly (AIA) on board the Solar Dynamic Observatory (SDO) above active region AR 11420 on February 22, 2012. Results: Observations show that a coronal loop disappeared in the 171 Å channel and appeared in the 304 Å line more than one hour later, which indicates a rapid cooling of the coronal loop from 1 MK to 0.05 MK. An energy estimation shows that the radiation is higher than the heat input, which indicates so-called catastrophic cooling. The cooling was accompanied by the formation of coronal rain in the form of falling cold plasma. We studied two different sequences of falling blobs. The first sequence includes three different blobs. The mean velocities of the blobs were estimated to be 50 km s-1, 60 km s-1 and 40 km s-1. A polynomial fit shows the different values of the acceleration for different blobs, which are lower than free-fall in the solar corona. The first and second blob move along the same path, but with and without acceleration, respectively. We performed simple numerical simulations for two consecutive blobs, which show that the second blob moves in a medium that is modified by the passage of the first blob. Therefore, the second blob has a relatively high speed and no acceleration, as is shown by observations. The second sequence includes two different blobs with mean velocities of 100 km s-1 and 90 km s-1, respectively. Conclusions: The formation of coronal rain blobs is connected with the process of catastrophic cooling. The different acceleration of different coronal rain blobs might be due to the different values in the density ratio of blob to corona. All blobs leave trails, which might be a result of continuous cooling in their tails. Two movies attached to Fig. 1 are available in electronic form at http://www.aanda.org

Mechanisms of anode power deposition in a low pressure free burning arc

NASA Technical Reports Server (NTRS)

Soulas, George C.; Myers, Roger M.

1994-01-01

Anode power deposition is a dominant power loss mechanism for arc jets and MPD thrusters. In this study, a free burning arc experiment was operated at pressures and current densities similar to those in arc jets and MPD thrusters in an attempt to identify the physics controlling this loss mechanism. Use of a free burning arc allowed for the isolation of independent variables controlling anode power deposition and provided a convenient and flexible way to cover a broad range of currents, anode surface pressures, and applied magnetic field strengths and orientations using an argon gas. Test results showed that anode power deposition decreased with increasing anode surface pressure up to 6.7 Pa (0.05 torr) and then became insensitive to pressure. Anode power increased with increasing arc current while the electron number density near the anode surface increased linearity. Anode power also increased with increasing applied magnetic field strength due to an increasing anode fall voltage. Applied magnetic field orientation had an effect only at high currents and low anode surface pressures, where anode power decreased when applied field lines intercepted the anode surface. The results demonstrated that anode power deposition was dominated by the current carrying electrons and that the anode fall voltage was the largest contributor. Furthermore, the results showed that anode power deposition can be reduced by operating at increased anode pressures, reduced arc currents, and applied magnetic field strengths and with magnetic field lines intercepting the anode.

a Portable Apparatus for Absolute Measurements of the Earth's Gravity.

NASA Astrophysics Data System (ADS)

Zumberge, Mark Andrew

We have developed a new, portable apparatus for making absolute measurements of the acceleration due to the earth's gravity. We use the method of interferometrically determining the acceleration of a freely falling corner -cube prism. The falling object is surrounded by a chamber which is driven vertically inside a fixed vacuum chamber. This falling chamber is servoed to track the falling corner -cube to shield it from drag due to background gas. In addition, the drag-free falling chamber removes the need for a magnetic release, shields the falling object from electrostatic forces, and provides a means of both gently arresting the falling object and quickly returning it to its start position, to allow rapid acquisition of data. A synthesized long period isolation device reduces the noise due to seismic oscillations. A new type of Zeeman laser is used as the light source in the interferometer, and is compared with the wavelength of an iodine stabilized laser. The times of occurrence of 45 interference fringes are measured to within 0.2 nsec over a 20 cm drop and are fit to a quadratic by an on-line minicomputer. 150 drops can be made in ten minutes resulting in a value of g having a precision of 3 to 6 parts in 10('9). Systematic errors have been determined to be less than 5 parts in 10('9) through extensive tests. Three months of gravity data have been obtained with a reproducibility ranging from 5 to 10 parts in 10('9). The apparatus has been designed to be easily portable. Field measurements are planned for the immediate future. An accuracy of 6 parts in 10('9) corresponds to a height sensitivity of 2 cm. Vertical motions in the earth's crust and tectonic density changes that may precede earthquakes are to be investigated using this apparatus.

A transportable cold atom inertial sensor for space applications

NASA Astrophysics Data System (ADS)

Ménoret, V.; Geiger, R.; Stern, G.; Cheinet, P.; Battelier, B.; Zahzam, N.; Pereira Dos Santos, F.; Bresson, A.; Landragin, A.; Bouyer, P.

2017-11-01

Atom interferometry has hugely benefitted from advances made in cold atom physics over the past twenty years, and ultra-precise quantum sensors are now available for a wide range of applications [1]. In particular, cold atom interferometers have shown excellent performances in the field of acceleration and rotation measurements [2,3], and are foreseen as promising candidates for navigation, geophysics, geo-prospecting and tests of fundamental physics such as the Universality of Free Fall (UFF). In order to carry out a test of the UFF with atoms as test masses, one needs to compare precisely the accelerations of two atoms with different masses as they fall in the Earth's gravitational field. The sensitivity of atom interferometers scales like the square of the time during which the atoms are in free fall, and on ground this interrogation time is limited by the size of the experimental setup to a fraction of a second. Sending an atom interferometer in space would allow for several seconds of excellent free-fall conditions, and tests of the UFF could be carried out with precisions as low as 10-15 [4]. However, cold atoms experiments rely on complex laser systems, which are needed to cool down and manipulate the atoms, and these systems are usually very sensitive to temperature fluctuations and vibrations. In addition, when operating an inertial sensor, vibrations are a major issue, as they deteriorate the performances of the instrument. This is why cold atom interferometers are usually used in ground based facilities, which provide stable enough environments. In order to carry out airborne or space-borne measurements, one has to design an instrument which is both compact and stable, and such that vibrations induced by the platform will not deteriorate the sensitivity of the sensor. We report on the operation of an atom interferometer on board a plane carrying out parabolic flights (Airbus A300 Zero-G, operated by Novespace). We have constructed a compact and stable laser setup, which is well suited for onboard applications. Our goal is to implement a dual-species Rb-K atom interferometer in order to carry out a test of the UFF in the plane. In this perspective, we are designing a dual-wavelength laser source, which will enable us to cool down and coherently manipulate the quantum states of both atoms. We have successfully tested a preliminary version of the source and obtained a double species magneto-optical trap (MOT).

Professional representation and the free-lance medical illustrator.

PubMed

Mount, K N; Daugherty, J

1994-01-01

We researched factors related to the success or failure in working relationships between free-lance medical illustrators and artist's representatives. In the fall of 1992, surveys were mailed to 230 medical illustrators; 105 (46%) completed surveys were returned. Respondents were divided into three categories: 1) medical illustrators currently represented, 2) medical illustrators previously represented, and 3) medical illustrators who had never been represented. Comparisons made among illustrators from the three groups included business practices, clientele, experience, and self-promotion techniques. These comparisons revealed notable differences and similarities between the three groups and were subsequently analyzed to identify the characteristics of medical illustrators who would benefit from professional representation.

Other Questions with Respect to the Weak Equivalence Principle

NASA Astrophysics Data System (ADS)

Smarandache, Florentin

2017-01-01

A disc rotating at high speed will exert out-of-plane forces resembling an accelerating field. Is the principle of equivalence also applicable for this process? Will someone inside an elevator in free-fall and rotating around its vertical centre, feel a gravitational force? Or will he feel a gravitational force larger than what equivalence principle requires? Does the equivalence principle remain applicable here? An airplane flies at an altitude of 1 km. The co-pilot drops an elevator-room without a passenger inside it. After one second has elapsed, the co-pilot drops four grenades in the direction of the freely-falling elevator's path. The question: Will the grenades reach the elevator before it reaches the ground? If no, why? If yes, which grenade? How will the air resistance influence the outcome?

Discrete anti-gravity

NASA Astrophysics Data System (ADS)

Noyes, H. Pierre; Starson, Scott

1991-03-01

Discrete physics, because it replaces time evolution generated by the energy operator with a global bit-string generator (program universe) and replaces fields with the relativistic Wheeler-Feynman action at a distance, allows the consistent formulation of the concept of signed gravitational charge for massive particles. The resulting prediction made by this version of the theory is that free anti-particles near the surface of the earth will fall up with the same acceleration that the corresponding particles fall down. So far as we can see, no current experimental information is in conflict with this prediction of our theory. The experiment crusis will be one of the anti-proton or anti-hydrogen experiments at CERN. Our prediction should be much easier to test than the small effects which those experiments are currently designed to detect or bound.

The shadow of a collapsing dark star

NASA Astrophysics Data System (ADS)

Schneider, Stefanie; Perlick, Volker

2018-06-01

The shadow of a black hole is usually calculated, either analytically or numerically, on the assumption that the black hole is eternal, i.e., that it has existed for all time. Here we ask the question of how this shadow comes about in the course of time when a black hole is formed by gravitational collapse. To that end we consider a star that is spherically symmetric, dark and non-transparent and we assume that it begins, at some instant of time, to collapse in free fall like a ball of dust. We analytically calculate the dependence on time of the angular radius of the shadow, first for a static observer who is watching the collapse from a certain distance and then for an observer who is falling towards the centre following the collapsing star.

Microscopic Optical Characterization of ZnO Bulk Crystals, Free Standing III-Nitride Substrates and III-V Structures for Non-Linear Optics

DTIC Science & Technology

2008-10-01

concentration (M.R. Phillips, M.Wagner, O.Gelhausen, V.Coleman, J.B. Brady, C. Jagadish, E. Malguth, A. Hoffmann, E.M. Goldys , J.J. Rusell; E.MRS...Malguth, A. Hoffmann, E.M. Goldys , J.J. Rusell; E.MRS Fall meeting, Symp. F, (Warsaw, Poland, 2004)); it suggests that the shift towards the red of

Free radical and overtone spectroscopy

NASA Technical Reports Server (NTRS)

Reilly, James P.

1991-01-01

In the fall of 1987 during a photoacoustic study of hydrogen peroxide's fourth vibrational overtone band, the remarkably clear and well resolved spectrum was observed. Its periodicity and K subband structure suggested that the spectrum was not of hydrogen peroxide but of a smaller near-prolate symmetric top molecule. Furthermore, the time dependent behavior of the signal indicated that chemical changes were taking place within the photoacoustic apparatus.

Stunt Barbie--A Laboratory Practicum Combining Constant Velocity and Constant Acceleration

ERIC Educational Resources Information Center

Hertting, Scott

2011-01-01

In preparing to teach the advanced physics course at my high school, I found it useful to work through the end of chapter problems in the book used by the advanced class. A problem on motion in one dimension involved a stunt woman in free fall from a tree limb onto a horse running beneath her. The problem presents a connected learning opportunity…

On the Use of History of Mathematics: An Introduction to Galileo's Study of Free Fall Motion

ERIC Educational Resources Information Center

Ponce Campuzano, Juan Carlos; Matthews, Kelly E.; Adams, Peter

2018-01-01

In this paper, we report on an experimental activity for discussing the concepts of speed, instantaneous speed and acceleration, generally introduced in first year university courses of calculus or physics. Rather than developing the ideas of calculus and using them to explain these basic concepts for the study of motion, we led 82 first year…

Long working hours and sleep disturbances: the Whitehall II prospective cohort study.

PubMed

Virtanen, Marianna; Ferrie, Jane E; Gimeno, David; Vahtera, Jussi; Elovainio, Marko; Singh-Manoux, Archana; Marmot, Michael G; Kivimäki, Mika

2009-06-01

To examine whether exposure to long working hours predicts various forms of sleep disturbance; short sleep, difficulty falling asleep, frequent waking, early waking and waking without feeling refreshed. Prospective study with 2 measurements of working hours (phase 3, 1991-1994 and phase 5, 1997-1999) and 2 measurements of subjective sleep disturbances (phase 5 and phase 7, 2002-2004). The Whitehall II study of British civil servants. Full time workers free of sleep disturbances at phase 5 and employed at phases 5 and 7 (n = 937-1594) or at phases 3, 5, and 7 (n = 886-1510). Working more than 55 hours a week, compared with working 35-40 hours a week, was related to incident sleep disturbances; demographics-adjusted odds ratio (95% CI) 1.98 (1.05, 3.76) for shortened sleeping hours, 3.68 (1.58, 8.58) for difficulty falling asleep; and 1.98 (1.04, 3.77) for waking without feeling refreshed. Repeat exposure to long working hours was associated with odds ratio 3.24 (1.45, 7.27) for shortened sleep, 6.66 (2.64, 16.83) for difficulty falling asleep, and 2.23 (1.16, 4.31) for early morning awakenings. Some associations were attenuated after adjustment for other risk factors. To a great extent, similar results were obtained using working hours as a continuous variable. Imputation of missing values supported the findings on shortened sleep and difficulty in falling asleep. Working long hours appears to be a risk factor for the development of shortened sleeping hours and difficulty falling asleep.

Comparison of the efficacy of preservative free ipratropium bromide and Atrovent nebuliser solution.

PubMed Central

Rafferty, P; Beasley, R; Holgate, S T

1988-01-01

The paradoxical bronchoconstriction observed with commercially available isotonic ipratropium bromide nebuliser solution (Atrovent) in patients with asthma results from an adverse reaction to the preservatives, benzalkonium chloride and ethylenediaminetetra-acetic acid (EDTA). The airway response to inhaled Atrovent and preservative free ipratropium bromide nebuliser solutions has been examined in a double blind study. On separate occasions 30 asthmatic subjects inhaled 2 ml of the solutions and airway calibre was measured in terms of FEV1 for 45 minutes. Atrovent nebuliser solution provoked a greater than 20% fall in FEV1 in five of the 30 subjects, whereas this did not occur after preservative free ipratropium bromide. Inhalation of the preservative free solution resulted in more rapid and greater overall bronchodilatation than Atrovent, with mean maximum increases in FEV1 of 29.2% and 18.5% respectively. It is concluded that the risk of paradoxical bronchoconstriction with ipratropium bromide is considerably reduced by removal of benzalkonium chloride and EDTA and that preservative free ipratropium bromide is a more potent bronchodilator than the currently available Atrovent solution. PMID:2971274

Signal transmissibility in marginal granular materials

NASA Astrophysics Data System (ADS)

Pinson, Matthew B.; Witten, Thomas A.

2016-12-01

We examine the ‘transmissibility’ of a simulated two-dimensional pack of frictionless disks formed by confining dilute disks in a shrinking, periodic box to the point of mechanical stability. Two opposite boundaries are then removed, thus allowing a set of free motions. Small free displacements on one boundary then induce proportional displacements on the opposite boundary. Transmissibility is the ability to distinguish different perturbations by their distant responses. We assess transmissibility by successively identifying free orthonormal modes of motion that have the smallest distant responses. The last modes to be identified in this ‘pessimistic’ basis are the most transmissive. The transmitted amplitudes of these most transmissive modes fall off exponentially with mode number. Similar exponential falloff is seen in a simple elastic medium, though the responsible modes differ greatly in structure in the two systems. Thus the marginal pack’s transmissibility is qualitatively similar to that of a simple elastic medium. We compare our results with recent findings based on the projection of the space of free motion onto interior sites.

Behavior of fluids in a weightless environment

NASA Technical Reports Server (NTRS)

Fester, D. A.; Eberhardt, R. N.; Tegart, J. R.

1977-01-01

Fluid behavior in a low-g environment is controlled primarily by surface tension forces. Certain fluid and system characteristics determine the magnitude of these forces for both a free liquid surface and liquid in contact with a solid. These characteristics, including surface tension, wettability or contact angle, system geometry, and the relationships governing their interaction, are discussed. Various aspects of fluid behavior in a low-g environment are then presented. This includes the formation of static interface shapes, oscillation and rotation of drops, coalescence, the formation of foams, tendency for cavitation, and diffusion in liquids which were observed during the Skylab fluid mechanics science demonstrations. Liquid reorientation and capillary pumping to establish equilibrium configurations for various system geometries, observed during various free-fall (drop-tower) low-g tests, are also presented. Several passive low-g fluid storage and transfer systems are discussed. These systems use surface tension forces to control the liquid/vapor interface and provide gas-free liquid transfer and liquid-free vapor venting.

Modeled tephra ages from lake sediments, base of Redoubt Volcano, Alaska

DOE Office of Scientific and Technical Information (OSTI.GOV)

Schiff, C J; Kaufman, D S; Wallace, K L

2007-02-25

A 5.6-m-long lake sediment core from Bear Lake, Alaska, located 22 km southeast of Redoubt Volcano, contains 67 tephra layers deposited over the last 8750 cal yr, comprising 15% of the total thickness of recovered sediment. Using 12 AMS {sup 14}C ages, along with the {sup 137}Cs and {sup 210}Pb activities of recent sediment, we evaluated different models to determine the age-depth relation of sediment, and to determine the age of each tephra deposit. The age model is based on a cubic smooth spline function that was passed through the adjusted tephra-free depth of each dated layer. The estimated agemore » uncertainty of the 67 tephras averages {+-} 105 yr (1{sigma}). Tephra-fall frequency at Bear Lake was among the highest during the past 500 yr, with eight tephras deposited compared to an average of 3.7 per 500 yr over the last 8500 yr. Other periods of increased tephra fall occurred 2500-3500, 4500-5000, and 7000-7500 cal yr. Our record suggests that Bear Lake experienced extended periods (1000-2000 yr) of increased tephra fall separated by shorter periods (500-1000 yr) of apparent quiescence. The Bear Lake sediment core affords the most comprehensive tephrochronology from the base of the Redoubt Volcano to date, with an average tephra-fall frequency of once every 130 yr.« less

Modeled tephra ages from lake sediments, base of Redoubt Volcano, Alaska

USGS Publications Warehouse

Schiff, C.J.; Kaufman, D.S.; Wallace, K.L.; Werner, A.; Ku, T.-L.; Brown, T.A.

2008-01-01

A 5.6-m-long lake sediment core from Bear Lake, Alaska, located 22 km southeast of Redoubt Volcano, contains 67 tephra layers deposited over the last 8750 cal yr, comprising 15% of the total thickness of recovered sediment. Using 12 AMS 14C ages, along with the 137Cs and 210Pb activities of recent sediment, we evaluated different models to determine the age-depth relation of the core, and to determine the age of each tephra deposit. The selected age model is based on a mixed-effect regression that was passed through the adjusted tephra-free depth of each dated layer. The estimated age uncertainty of the 67 tephras averages ??105 yr (95% confidence intervals). Tephra-fall frequency at Bear Lake was among the highest during the past 500 yr, with eight tephras deposited compared to an average of 3.7/500 yr over the last 8500 yr. Other periods of increased tephra fall occurred 2500-3500, 4500-5000, and 7000-7500 cal yr. Our record suggests that Bear Lake experienced extended periods (1000-2000 yr) of increased tephra fall separated by shorter periods (500-1000 yr) of apparent quiescence. The Bear Lake sediment core affords the most comprehensive tephrochronology from the base of the Redoubt Volcano to date, with an average tephra-fall frequency of one every 130 yr. ?? 2007 Elsevier Ltd. All rights reserved.

On the notion of free will in the Free Will Theorem

NASA Astrophysics Data System (ADS)

Landsman, Klaas

2017-02-01

The (Strong) Free Will Theorem (FWT) of Conway and Kochen (2009) on the one hand follows from uncontroversial parts of modern physics and elementary mathematical and logical reasoning, but on the other hand seems predicated on an undefined notion of free will (allowing physicists to "freely choose" the settings of their experiments). This makes the theorem philosophically vulnerable, especially if it is construed as a proof of indeterminism or even of libertarian free will (as Conway & Kochen suggest). However, Cator and Landsman (Foundations of Physics 44, 781-791, 2014) previously gave a reformulation of the FWT that does not presuppose indeterminism, but rather assumes a mathematically specific form of such "free choices" even in a deterministic world (based on a non-probabilistic independence assumption). In the present paper, which is a philosophical sequel to the one just mentioned, I argue that the concept of free will used in the latter version of the FWT is essentially the one proposed by Lewis (1981), also known as 'local miracle compatibilism' (of which I give a mathematical interpretation that might be of some independent interest also beyond its application to the FWT). As such, the (reformulated) FWT in my view challenges compatibilist free will à la Lewis (albeit in a contrived way via bipartite EPR-type experiments), falling short of supporting libertarian free will.

Powerful nuclear technology, anywhere, requires functioning system of free elections

NASA Astrophysics Data System (ADS)

Synek, Miroslav

2000-03-01

Historical development on our planet, utilizing the knowledge of physics, has reached a powerful technology of nuclear intercontinental ballistic missiles, conceivably controllable through a computerized ``push-button". Whenever this technology falls under the control of an irresponsible, miscalculating, or, insane, dictator, with powerful means of a mass-produced nuclear built-up, anywhere on our planet, the very survival of all humanity on our planet could be threatened. Therefore, it is a historical urgency that this technology is under the control by a government of the people, by the people and for the people, based on a sufficiently secure system of free elections, in any country on our planet, wherever and whenever such a threatening possibility exists.

A Study of Some Issues Which May Influence the Question of a Role for Free-Fall Weapons.

DTIC Science & Technology

1981-06-01

Environment Precision-Guided Munitions The Middle East American Public Ophinion General Target Categories The Horn of Africa Force Application Environ- and...DISCUSSION ........... ....................... 5 I. THE GENERAL MILIEU OF FORCE APPLICATION IN THE 198OS ........ ii A. Some Aspects of the...Force Application Environment of the 1980s ......... .. 32 IV. GENERAL TARGET CATEGORIES AND DELIVERY SYSTEMS ............ ... 38 A. Air Supremacy

Are You Happy Now? A Fictional Narrative Exploration of Educator Experiences in Higher Education during the Time of #FeesMustFall

ERIC Educational Resources Information Center

Müller, Marguerite

2017-01-01

In this performative text a narrative arts-based approach is used to explore the connections between educator identity and the current issues arising in the broader South African higher education landscape. Written as a fictional narrative it is an exploration of some of my experiences at the University of the Free State between 2014 and 2016. The…

Transient analysis of an IVHM grapple impact test

NASA Technical Reports Server (NTRS)

Hill, R. G.

1972-01-01

A lumped mass model was used to represent the impact condition between a fuel duct and an IVHM in-vessel fuel handling machine. The nonlinear effects of a Bellville spring and the free fall impact of the fuel duct on the IVHM were included. The purpose of the tests was to determine the loads on the fuel duct due to the impact. A comparison between experimental and theoretical results is presented.

Dismantling Terrorism: Developing Actionable Solutions for Today’s Plague of Violence

DTIC Science & Technology

2007-11-01

Press, 2006. Weapons of Mass Destruction Commission. Weapons of Terror: Freeing the World of Nuclear Biological and Chemical Arms, Stockholm, Sweden...Introduction to Weapons of Mass Destruction: Radioloqical, Chemical , and Biological. Hoboken: Wiley-Interscience, 2004. (U 793 .L36 2004) Martin, Gus, ed...electronic. Pita, Rene. "Assessing AI-Qaeda’s Chemical Threat." International Journal of Intelligence and Counterintelligence 20.3 (Fall 2007): 480

Approximate formula for recalescence in binary eutectic alloys

NASA Technical Reports Server (NTRS)

Ohsaka, K.; Trinh, E. H.

1993-01-01

Supercooling of a liquid prior to the nucleation of a solid and the subsequent rapid growth are necessary conditions for producing novel microstructures including metastable phases which are not formed by conventional solidification processes. Since containerless techniques, such as levitation and free fall of a sample, are capable of achieving a significant supercooling level of liquids, they are under consideration as possible techniques for material processing on earth and in space.

MOOCs and the AI-Stanford Like Courses: Two Successful and Distinct Course Formats for Massive Open Online Courses

ERIC Educational Resources Information Center

Rodriguez, C. Osvaldo

2012-01-01

Open online courses (OOC) with a massive number of students have represented an important development for online education in the past years. A course on artificial intelligence, CS221, at the University of Stanford was offered in the fall of 2011 free and online which attracted 160,000 registered students. It was one of three offered as an…

Flapping Wing Flight Dynamic Modeling

DTIC Science & Technology

2011-08-22

cases. Pesavento and Wang [24] solved the two dimensional Navier-Stokes equations in relation to a piece of free falling paper at Reynolds number near...von Karman, T. and Burgers, J. M., Gerneral Aerodynamic Theory - Perfect Fluids , Vol. II, Julius Springer, Berlin, 1935. [24] Pesavento , U. and Wang...2004, pp. 14. [25] Andersen, A., Pesavento , U., and Wang, Z. J., Unsteady aerodynamics of uttering and tumbling plates, Journal of Fluid Mechanics

Youth Access to Violent Video Games on Trial: The U.S. Supreme Court Takes the Case

ERIC Educational Resources Information Center

Bickford, Rebekah S.

2010-01-01

This fall, the U.S. Supreme Court will hear arguments in a case that promises to affect the lives of many children. Up for debate is whether a law aimed at curbing children's access to violent video games violates their constitutional right to free speech. Signed 5 years ago by Governor Schwarzenegger, the California statute, which has yet to take…

The Problem with Precision: Managing Expectations for Air Power

DTIC Science & Technology

2013-03-01

contributed to inflated expectations about discrimination in warfare. The World War II strategic bombing campaign was portrayed in film footage of...skies dotted with bombers, escorts, free-falling bombs from open bomb bay doors, and impressive explosions on the ground below; what the films did not...Committee on Public Information in order to influence America’s public opinion on the World War.88 The organization used films , newspapers, radio

STAR FORMATION RELATIONS IN THE MILKY WAY

DOE Office of Scientific and Technical Information (OSTI.GOV)

Vutisalchavakul, Nalin; Evans II, Neal J.; Heyer, Mark, E-mail: nje@astro.as.utexas.edu

2016-11-01

The relations between star formation and properties of molecular clouds (MCs) are studied based on a sample of star-forming regions in the Galactic Plane. Sources were selected by having radio recombination lines to provide identification of associated MCs and dense clumps. Radio continuum emission and mid-infrared emission were used to determine star formation rates (SFRs), while {sup 13}CO and submillimeter dust continuum emission were used to obtain the masses of molecular and dense gas, respectively. We test whether total molecular gas or dense gas provides the best predictor of SFR. We also test two specific theoretical models, one relying onmore » the molecular mass divided by the free-fall time, the other using the free-fall time divided by the crossing time. Neither is supported by the data. The data are also compared to those from nearby star-forming regions and extragalactic data. The star formation “efficiency,” defined as SFR divided by mass, spreads over a large range when the mass refers to molecular gas; the standard deviation of the log of the efficiency decreases by a factor of three when the mass of relatively dense molecular gas is used rather than the mass of all of the molecular gas.« less

Compact mode-locked diode laser system for high precision frequency comparisons in microgravity

NASA Astrophysics Data System (ADS)

Christopher, H.; Kovalchuk, E. V.; Wicht, A.; Erbert, G.; Tränkle, G.; Peters, A.

2017-11-01

Nowadays cold atom-based quantum sensors such as atom interferometers start leaving optical labs to put e.g. fundamental physics under test in space. One of such intriguing applications is the test of the Weak Equivalence Principle, the Universality of Free Fall (UFF), using different quantum objects such as rubidium (Rb) and potassium (K) ultra-cold quantum gases. The corresponding atom interferometers are implemented with light pulses from narrow linewidth lasers emitting near 767 nm (K) and 780 nm (Rb). To determine any relative acceleration of the K and Rb quantum ensembles during free fall, the frequency difference between the K and Rb lasers has to be measured very accurately by means of an optical frequency comb. Micro-gravity applications not only require good electro-optical characteristics but are also stringent in their demand for compactness, robustness and efficiency. For frequency comparison experiments the rather complex fiber laser-based frequency comb system may be replaced by one semiconductor laser chip and some passive components. Here we present an important step towards this direction, i.e. we report on the development of a compact mode-locked diode laser system designed to generate a highly stable frequency comb in the wavelength range of 780 nm.

Tidal compression of a star by a large black hole. I Mechanical evolution and nuclear energy release by proton capture

NASA Astrophysics Data System (ADS)

Carter, B.; Luminet, J.-P.

1983-05-01

The gross qualitative behaviour of a star plunging deeply within the Roche tidal radius, RR, of a large black hole to a pericentre radius β-1RR, with β≳3, is examined using a simplified affine star model whose evolution is canonically determined by a Lagrangian formalism. In Phase I, for R≳RR, the star remains in only slightly distorted self-gravitating quasi-equilibrium, but in Phase II its particles undergo approximately free fall in the strong external tidal field within the Roche radius. In Phase III the compression is halted and reversed by the build-up of pressure in a highly flattened pancake configuration, in which adiabatic heating raises the temperature to a maximum given in most cases by Θm ≍ β-2Θ* where Θ* is the equilibrium core temperature. In Phase IV the matter expands again in approximately free fall, and in Phase V, as the star moves outside the Roche radius, pressure and self-gravitational forces again come into play. For stars rich in intermediate weight elements, nuclear energy release by proton capture in Phase III is shown to be important. Consideration of the more spectacular possibility of helium detonation is postponed until Part II.

DOE Office of Scientific and Technical Information (OSTI.GOV)

Wu, Benjamin; Tan, Jonathan C.; Christie, Duncan

We study giant molecular cloud (GMC) collisions and their ability to trigger star cluster formation. We further develop our three-dimensional magnetized, turbulent, colliding GMC simulations by implementing star formation subgrid models. Two such models are explored: (1) “Density-Regulated,” i.e., fixed efficiency per free-fall time above a set density threshold and (2) “Magnetically Regulated,” i.e., fixed efficiency per free-fall time in regions that are magnetically supercritical. Variations of parameters associated with these models are also explored. In the non-colliding simulations, the overall level of star formation is sensitive to model parameter choices that relate to effective density thresholds. In the GMCmore » collision simulations, the final star formation rates and efficiencies are relatively independent of these parameters. Between the non-colliding and colliding cases, we compare the morphologies of the resulting star clusters, properties of star-forming gas, time evolution of the star formation rate (SFR), spatial clustering of the stars, and resulting kinematics of the stars in comparison to the natal gas. We find that typical collisions, by creating larger amounts of dense gas, trigger earlier and enhanced star formation, resulting in 10 times higher SFRs and efficiencies. The star clusters formed from GMC collisions show greater spatial substructure and more disturbed kinematics.« less

Prospective randomised trial of early cytotoxic therapy for recurrent colorectal carcinoma detected by serum CEA.

PubMed Central

Hine, K R; Dykes, P W

1984-01-01

Of 663 patients treated with radical surgery for colorectal cancer, 52 showed a progressive rise in serum carcinoembryonic antigen (CEA) with no other evidence of recurrent disease and were randomised in a prospective study of chemotherapy. Twenty six patients in the treatment group received 5FU and methyl CCNU from the time of randomisation and the remaining 26 controls were given further therapy only if there were clinical indications. All patients were followed for five years or until their death and all but one (control) developed clinical evidence of recurrence. Overall there was no significant difference between the two groups with respect to disease free interval and survival. Whereas the rise in CEA in controls was generally progressive, marked inflections on the CEA curves were seen in the majority of patients receiving early treatment. Eight of 26 treated patients showed a fall in CEA of greater than 20% two months after starting therapy. These patients had a median disease free interval of 90 weeks and a median survival of 107 weeks, these figures being longer than those of treated patients who did not show a fall in CEA and control patients. The serum CEA therefore appeared to give important prognostic information in patients receiving cytotoxic treatment. Early therapy was generally well tolerated. PMID:6376291

Microgravity: Teacher's guide with activities for physical science

NASA Technical Reports Server (NTRS)

Vogt, Gregory L.; Wargo, Michael J.; Rosenberg, Carla B. (Editor)

1995-01-01

This guide is an educational tool for teachers of grades 5 through 12. It is an introduction to microgravity and its application to spaceborne laboratory experiments. Specific payloads and missions are mentioned with limited detail, including Spacelab, the International Microgravity Laboratory, and the United States Microgravity Laboratory. Activities for students demonstrate chemistry, mathematics, and physics applications of microgravity. Activity objectives include: modeling how satellites orbit Earth; demonstrating that free fall eliminates the local effects of gravity; measuring the acceleration environments created by different motions; using a plasma sheet to observe acceleration forces that are experienced on board a space vehicle; demonstrating how mass can be measured in microgravity; feeling how inertia affects acceleration; observing the gravity-driven fluid flow that is caused by differences in solution density; studying surface tension and the fluid flows caused by differences in surface tension; illustrating the effects of gravity on the burning rate of candles; observing candle flame properties in free fall; measuring the contact angle of a fluid; illustrating the effects of gravity and surface tension on fiber pulling; observing crystal growth phenomena in a 1-g environment; investigating temperature effects on crystal growth; and observing crystal nucleation and growth rate during directional solidification. Each activity includes a background section, procedure, and follow-up questions.

The New and Old Europe: East-West Split in Pharmaceutical Spending.

PubMed

Jakovljevic, Mihajlo; Lazarevic, Marija; Milovanovic, Olivera; Kanjevac, Tatjana

2016-01-01

HIGHLIGHTS Since the geopolitical developments of 1989, former centrally planned economies of Eastern Europe followed distinctively different pathways in national pharmaceutical expenditure evolution as compared to their free market Western European counterparts.Long term spending on pharmaceuticals expressed as percentage of total health expenditure was falling in free market economies as of 1989. Back in early 1990s it was at higher levels in transitional Eastern European countries and actually continued to grow further.Public financing share of total pharmaceutical expenditure was steadily falling in most Central and Eastern European countries over the recent few decades. Opposed scenario were EU-15 countries which successfully increased their public funding of prescription medicines for the sake of their citizens.Pace of annual increase in per capita spending on medicines in PPP terms, was at least 20% faster in Eastern Europe compared to their Western counterparts. During the same years, CEE region was expanding their pharmaceuticals share of health spending in eight fold faster annual rate compared to the EU 15.Private and out-of-pocket expenditure became dominant in former socialist countries. Affordability issues coupled with growing income inequality in transitional economies will present a serious challenge to equitable provision and sustainable financing of pharmaceuticals in the long run.

Inflow velocities of cold flows streaming into massive galaxies at high redshifts

NASA Astrophysics Data System (ADS)

Goerdt, Tobias; Ceverino, Daniel

2015-07-01

We study the velocities of the accretion along streams from the cosmic web into massive galaxies at high redshift with the help of three different suites of AMR hydrodynamical cosmological simulations. The results are compared to free-fall velocities and to the sound speeds of the hot ambient medium. The sound speed of the hot ambient medium is calculated using two different methods to determine the medium's temperature. We find that the simulated cold stream velocities are in violent disagreement with the corresponding free-fall profiles. The sound speed is a better albeit not always correct description of the cold flows' velocity. Using these calculations as a first order approximation for the gas inflow velocities vinflow = 0.9 vvir is given. We conclude from the hydrodynamical simulations as our main result that the velocity profiles for the cold streams are constant with radius. These constant inflow velocities seem to have a `parabola-like' dependency on the host halo mass in units of the virial velocity that peaks at Mvir = 1012 M⊙ and we also propose that the best-fitting functional form for the dependency of the inflow velocity on the redshift is a square root power-law relation: v_inflow ∝ √{z + 1} v_vir.

Structure, Dynamics, and Deuterium Fractionation of Massive Pre-stellar Cores

NASA Astrophysics Data System (ADS)

Goodson, Matthew D.; Kong, Shuo; Tan, Jonathan C.; Heitsch, Fabian; Caselli, Paola

2016-12-01

High levels of deuterium fraction in N2H+ are observed in some pre-stellar cores. Single-zone chemical models find that the timescale required to reach observed values ({D}{frac}{{{N}}2{{{H}}}+}\\equiv {{{N}}}2{{{D}}}+/{{{N}}}2{{{H}}}+≳ 0.1) is longer than the free-fall time, possibly 10 times longer. Here, we explore the deuteration of turbulent, magnetized cores with 3D magnetohydrodynamics simulations. We use an approximate chemical model to follow the growth in abundances of N2H+ and N2D+. We then examine the dynamics of the core using each tracer for comparison to observations. We find that the velocity dispersion of the core as traced by N2D+ appears slightly sub-virial compared to predictions of the Turbulent Core Model of McKee & Tan, except at late times just before the onset of protostar formation. By varying the initial mass surface density, the magnetic energy, the chemical age, and the ortho-to-para ratio of H2, we also determine the physical and temporal properties required for high deuteration. We find that low initial ortho-to-para ratios (≲ 0.01) and/or multiple free-fall times (≳ 3) of prior chemical evolution are necessary to reach the observed values of deuterium fraction in pre-stellar cores.

DOE Office of Scientific and Technical Information (OSTI.GOV)

Carbone, L.; Ciani, G.; Dolesi, R.

The low frequency sensitivity of space-borne gravitational wave observatories will depend critically on the geodesic purity of the trajectories of orbiting test masses. Fluctuations in the temperature difference across the enclosure surrounding the free-falling test mass can produce noisy forces through several processes, including the radiometric effect, radiation pressure, and outgassing. We present here a detailed experimental investigation of thermal gradient-induced forces for the Laser Interferometer Space Antenna (LISA) gravitational wave mission and the LISA Pathfinder, employing high resolution torsion pendulum measurements of the torque on a LISA-like test mass suspended inside a prototype of the LISA gravitational reference sensormore » that will surround the test mass in orbit. The measurement campaign, accompanied by numerical simulations of the radiometric and radiation pressure effects, allows a more accurate and representative characterization of thermal-gradient forces in the specific geometry and environment relevant to LISA free-fall. The pressure dependence of the measured torques allows clear identification of the radiometric effect, in quantitative agreement with the model developed. In the limit of zero gas pressure, the measurements are most likely dominated by outgassing, but at a low level that does not threaten the current LISA noise estimate, which assumes a maximum net force per degree of temperature difference of 100(pN/K) for the overall thermal gradient-induced effects.« less

The Microgravity Demonstrator

NASA Technical Reports Server (NTRS)

Rogers, Melissa J. B.; Wargo, Michael J.

1999-01-01

The Demonstrator is a tool to create microgravity conditions in your classroom. A series of demonstrations is used to provide a dramatically visual, physical connection between free-fall and microgravity conditions and to understand why various types of experiments are performed under microgravity conditions. A wealth of back-round material on free-fall, microgravity, and micro-gravity sciences is available in two educational documents available through the NASA Teacher Resource Centers: Microgravity-Activity Guide for Science, Mathematics, and Technology Education, and The Mathematics of Microgravity. The remainder of this manual is divided into five sections. The first explains how to put the Microgravity Demonstrator together. The next section introduces the individual demonstrations and discusses the underlying physical science concepts. Following that are detailed steps for conducting each demonstration to make your use of the Demonstrator most effective. Next are some ideas on how to make your own Microgravity Demonstrator. The last section is a tips and troubleshooting guide for video connections and operations. If you have one of the NASA Microgravity Demonstrators, this entire manual should be useful. If you have a copy of the Microgravity Demonstrator Videotape and would like to use that as a teaching tool, the Demonstrations and Scientific Background section of this manual will give you insight into the science areas studied in microgravity.

Complex Plasmas under free fall conditions aboard the International Space Station

NASA Astrophysics Data System (ADS)

Konopka, Uwe; Thomas, Edward, Jr.; Funk, Dylan; Doyle, Brandon; Williams, Jeremiah; Knapek, Christina; Thomas, Hubertus

2017-10-01

Complex Plasmas are dynamically dominated by massive, highly negatively charged, micron-sized particles. They are usually strongly coupled and as a result can show fluid-like behavior or undergo phase transitions to form crystalline structures. The dynamical time scale of these systems is easily accessible in experiments because of the relatively high mass/inertia of the particles. However, the high mass also leads to sedimentation effects and as a result prevents the conduction of large scale, fully three dimensional experiments that are necessary to utilize complex plasmas as model systems in the transition to continuous media. To reduce sedimentation influences it becomes necessary to perform experiments in a free-fall (``microgravity'') environment, such as the ISS based experiment facility ``Plasma-Kristall-4'' (``PK-4''). In our paper we will present our recently started research activities to investigate the basic properties of complex plasmas by utilizing the PK-4 experiment facility aboard the ISS. We further give an overview of developments towards the next generation experiment facility ``Ekoplasma'' (formerly named ``PlasmaLab'') and discuss potential additional small-scale space-based experiment scenarios. This work was supported by the JPL/NASA (JPL-RSA 1571699), the US Dept. of Energy (DE-SC0016330) and the NSF (PHY-1613087).

An Investigation of the Drag and Pressure Recovery of a Submerged Inlet and a Nose Inlet in the Transonic Flight Range with Free-fall Models

NASA Technical Reports Server (NTRS)

Selna, James; Schlaff, Bernard A

1951-01-01

The drag and pressure recovery of an NACA submerged-inlet model and an NACA series I nose-inlet model were investigated in the transonic flight range. The tests were conducted over a mass-flow-ratio range of 0.4 to 0.8 and a Mach number range of about 0.8 to 1.10 employing large-scale recoverable free-fall models. The results indicate that the Mach number of drag divergence of the inlet models was about the same as that of a basic model without inlets. The external drag coefficients of the nose-inlet model were less than those of the submerged-inlet model throughout the test range. The difference in drag coefficient based on the maximum cross-sectional area of the models was about 0.02 at supersonic speeds and about 0.015 at subsonic speeds. For a hypothetical airplane with a ratio of maximum fuselage cross-sectional area to wing area of 0.06, the difference in airplane drag coefficient would be relatively small, about 0.0012 at supersonic speeds and about 0.0009 at subsonic speeds. Additional drag comparisons between the two inlet models are made considering inlet incremental and additive drag.

Discrete anti-gravity

DOE Office of Scientific and Technical Information (OSTI.GOV)

Noyes, H.P.; Starson, S.

1991-03-01

Discrete physics, because it replaces time evolution generated by the energy operator with a global bit-string generator (program universe) and replaces fields'' with the relativistic Wheeler-Feynman action at a distance,'' allows the consistent formulation of the concept of signed gravitational charge for massive particles. The resulting prediction made by this version of the theory is that free anti-particles near the surface of the earth will fall'' up with the same acceleration that the corresponding particles fall down. So far as we can see, no current experimental information is in conflict with this prediction of our theory. The experiment crusis willmore » be one of the anti-proton or anti-hydrogen experiments at CERN. Our prediction should be much easier to test than the small effects which those experiments are currently designed to detect or bound. 23 refs.« less

High energy particles with negative and positive energies in the vicinity of black holes

NASA Astrophysics Data System (ADS)

Grib, A. A.; Pavlov, Yu. V.

2014-07-01

It is shown that the energy in the centre of mass frame of two colliding particles in free fall at any point of the ergosphere of the rotating black hole can grow without limit for fixed energy values of particles on infinity. The effect takes place for large negative values of the angular momentum of one of the particles. It occurs that the geodesics with negative energy in equatorial plane of rotating black holes cannot originate or terminate inside the ergosphere. Their length is always finite and this leads to conclusion that they must originate and terminate inside the gravitational radius of the ergosphere. The energy in the centre of mass frame of one particle falling into the gravitational radius and the other arriving from the area inside it is growing without limit on the horizon.

Two Distinct Secondary Carbonate Species in OC Meteorites from Antarctica are Possible Analogs for Mars Carbonates

NASA Technical Reports Server (NTRS)

Evans, M. E.; Niles, P. B.; Locke, D. R.; Chapman, P.

2016-01-01

Meteorites falling in Antarctica are captured in ice and stored until the glacial flow transports them to the surface where they can be collected. Prior to collection, they are altered during interactions between the rock, the cryosphere, and the hydrosphere. The purpose of this study is to characterize the stable isotope values of terrestrial, secondary carbonate minerals from Ordinary Chondrite (OC) meteorites collected in Antarctica. This facilitates better understanding of terrestrial weathering in martian meteorites as well as mechanisms for weathering in cold, arid environments as an analog to Mars. OC samples were selected for analysis based upon size and collection proximity to known martian meteorites. They were also selected based on petrologic type (3+) such that they were likely to be carbonate-free before falling to Earth.

Empirical correlation between hydrophobic free energy and aqueous cavity surface area

DOE Office of Scientific and Technical Information (OSTI.GOV)

Reynolds, J.A.; Gilbert, D.B.; Tanford, C.

1974-08-01

The unitary free energy of transfer of a hydrocarbon molecule from a hydrocarbon solvent to an aqueous medium is a measure of the hydrophobic interaction in the aqueous medium. We have reexamined available data on this phenomenon and have confirmed that the free energy for saturated hydrocarbons is proportional to the surface area of the cavity created by the solute in the aqueous solution, with the same proportionality constant for linear, branched, and cyclic hydrocarbon molecules. The numerical value of the proportionality constant is uncertain because absolute and self-consistent area measurements are not available. We estimate that it falls betweenmore » 20 and 25 cal/mole per Angstrom/sup 2/ at 25/sup 0/ (for areas measured at the distance of closest approach of water molecules), which is significantly less than the figure of 33 cal/mole per Angstrom/sup 2/ that has been assigned to the same parameter by Hermann.« less

gLISA: geosynchronous laser interferometer space antenna concepts with off-the-shelf satellites.

PubMed

Tinto, M; DeBra, D; Buchman, S; Tilley, S

2015-01-01

We discuss two geosynchronous gravitational wave (GW) mission concepts, which we generically name gLISA. One relies on the science instrument hosting program onboard geostationary commercial satellites, while the other takes advantage of recent developments in the aerospace industry that result in dramatic satellite and launching vehicle cost reductions for a dedicated geosynchronous mission. To achieve the required level of disturbance free-fall onboard these large and heavy platforms, we propose a new drag-free system, which we have named "two-stage" drag-free. It incorporates the Modular Gravitational Reference Sensor (developed at Stanford University) and does not rely on the use of μN thrusters. Although both mission concepts are characterized by different technical and programmatic challenges, individually they could be flown and operated at a cost significantly lower than those of previously envisioned gravitational wave missions, and in the year 2015 we will perform at JPL a detailed selecting mission analysis.

Disinfection byproduct yields from the chlorination of natural waters

USGS Publications Warehouse

Rathbun, R.E.

1996-01-01

Yields for the formation of trihalomethane and nonpurgeable total organic-halide disinfection byproducts were determined as a function of pH and initial free-chlorine concentration for the chlorination of water from the Mississippi, Missouri, and Ohio Rivers. Samples were collected at 12 sites on the Mississippi River from Minneapolis, MN, to New Orleans. LA, and on the Missouri and Ohio Rivers 1.6 km above their confluences with the Mississippi during the summer, fall, and spring seasons of the year. Yields varied little with distance along the Mississippi River, although the dissolved organic-carbon concentration decreased considerably with distance downstream. Yields for the Missouri and Ohio were comparable to yields for the Mississippi, despite much higher bromide concentrations for the Missouri and Ohio. Trihalomethane yields increased as the pH and initial free- chlorine concentration increased. Nonpurgeable total organic-halide yields also increased as the initial free-chlorine concentration increased, but decreased as the pH increased.

Identifying balance impairments in people with Parkinson's disease using video and wearable sensors.

PubMed

Stack, Emma; Agarwal, Veena; King, Rachel; Burnett, Malcolm; Tahavori, Fatemeh; Janko, Balazs; Harwin, William; Ashburn, Ann; Kunkel, Dorit

2018-05-01

Falls and near falls are common among people with Parkinson's (PwP). To date, most wearable sensor research focussed on fall detection, few studies explored if wearable sensors can detect instability. Can instability (caution or near-falls) be detected using wearable sensors in comparison to video analysis? Twenty-four people (aged 60-86) with and without Parkinson's were recruited from community groups. Movements (e.g. walking, turning, transfers and reaching) were observed in the gait laboratory and/or at home; recorded using clinical measures, video and five wearable sensors (attached on the waist, ankles and wrists). After defining 'caution' and 'instability', two researchers evaluated video data and a third the raw wearable sensor data; blinded to each other's evaluations. Agreement between video and sensor data was calculated on stability, timing, step count and strategy. Data was available for 117 performances: 82 (70%) appeared stable on video. Ratings agreed in 86/117 cases (74%). Highest agreement was noted for chair transfer, timed up and go test and 3 m walks. Video analysts noted caution (slow, contained movements, safety-enhancing postures and concentration) and/or instability (saving reactions, stopping after stumbling or veering) in 40/134 performances (30%): raw wearable sensor data identified 16/35 performances rated cautious or unstable (sensitivity 46%) and 70/82 rated stable (specificity 85%). There was a 54% chance that a performance identified from wearable sensors as cautious/unstable was so; rising to 80% for stable movements. Agreement between wearable sensor and video data suggested that wearable sensors can detect subtle instability and near-falls. Caution and instability were observed in nearly a third of performances, suggesting that simple, mildly challenging actions, with clearly defined start- and end-points, may be most amenable to monitoring during free-living at home. Using the genuine near-falls recorded, work continues to automatically detect subtle instability using algorithms. Crown Copyright © 2018. Published by Elsevier B.V. All rights reserved.

Constraining eye movement in individuals with Parkinson's disease during walking turns.

PubMed

Ambati, V N Pradeep; Saucedo, Fabricio; Murray, Nicholas G; Powell, Douglas W; Reed-Jones, Rebecca J

2016-10-01

Walking and turning is a movement that places individuals with Parkinson's disease (PD) at increased risk for fall-related injury. However, turning is an essential movement in activities of daily living, making up to 45 % of the total steps taken in a given day. Hypotheses regarding how turning is controlled suggest an essential role of anticipatory eye movements to provide feedforward information for body coordination. However, little research has investigated control of turning in individuals with PD with specific consideration for eye movements. The purpose of this study was to examine eye movement behavior and body segment coordination in individuals with PD during walking turns. Three experimental groups, a group of individuals with PD, a group of healthy young adults (YAC), and a group of healthy older adults (OAC), performed walking and turning tasks under two visual conditions: free gaze and fixed gaze. Whole-body motion capture and eye tracking characterized body segment coordination and eye movement behavior during walking trials. Statistical analysis revealed significant main effects of group (PD, YAC, and OAC) and visual condition (free and fixed gaze) on timing of segment rotation and horizontal eye movement. Within group comparisons, revealed timing of eye and head movement was significantly different between the free and fixed gaze conditions for YAC (p < 0.001) and OAC (p < 0.05), but not for the PD group (p > 0.05). In addition, while intersegment timings (reflecting segment coordination) were significantly different for YAC and OAC during free gaze (p < 0.05), they were not significantly different in PD. These results suggest individuals with PD do not make anticipatory eye and head movements ahead of turning and that this may result in altered segment coordination during turning. As such, eye movements may be an important addition to training programs for those with PD, possibly promoting better coordination during turning and potentially reducing the risk of falls.

Neural correlates of gait variability in people with multiple sclerosis with fall history.

PubMed

Kalron, Alon; Allali, Gilles; Achiron, Anat

2018-05-28

Investigate the association between step time variability and related brain structures in accordance with fall status in people with multiple sclerosis (PwMS). The study included 225 PwMS. A whole-brain MRI was performed by a high-resolution 3.0-Telsa MR scanner in addition to volumetric analysis based on 3D T1-weighted images using the FreeSurfer image analysis suite. Step time variability was measured by an electronic walkway. Participants were defined as "fallers" (at least two falls during the previous year) and "non-fallers". One hundred and five PwMS were defined as fallers and had a greater step time variability compared to non-fallers (5.6% (S.D.=3.4) vs. 3.4% (S.D.=1.5); p=0.001). MS fallers exhibited a reduced volume in the left caudate and both cerebellum hemispheres compared to non-fallers. By using a linear regression analysis no association was found between gait variability and related brain structures in the total cohort and non-fallers group. However, the analysis found an association between the left hippocampus and left putamen volumes with step time variability in the faller group; p=0.031, 0.048, respectively, controlling for total cranial volume, walking speed, disability, age and gender. Nevertheless, according to the hierarchical regression model, the contribution of these brain measures to predict gait variability was relatively small compared to walking speed. An association between low left hippocampal, putamen volumes and step time variability was found in PwMS with a history of falls, suggesting brain structural characteristics may be related to falls and increased gait variability in PwMS. This article is protected by copyright. All rights reserved. This article is protected by copyright. All rights reserved.

Gait and risk of falls associated with frontal cognitive functions at different stages of Alzheimer's disease.

PubMed

Coelho, Flávia Gomes de Melo; Stella, Florindo; de Andrade, Larissa Pires; Barbieri, Fabio Augusto; Santos-Galduróz, Ruth Ferreira; Gobbi, Sebastião; Costa, José Luiz Riani; Gobbi, Lilian Teresa Bucken

2012-09-01

The decline in frontal cognitive functions contributes to alterations of gait and increases the risk of falls in patients with dementia, a category which included Alzheimer's disease (AD). The objective of the present study was to compare the gait parameters and the risk of falls among patients at different stages of AD, and to relate these variables with cognitive functions. This is a cross-sectional study with 23 patients with mild and moderate AD. The Clinical Dementia Rating was used to classify the dementia severity. The kinematic parameters of gait (cadence, stride length, and stride speed) were analyzed under two conditions: (a) single task (free gait) and (b) dual task (walking and counting down). The risk of falls was evaluated using the Timed Up-and-Go test. The frontal cognitive functions were evaluated using the Frontal Assessment Battery (FAB), the Clock Drawing Test (CDT) and the Symbol Search Subtest. The patients who were at the moderate stage suffered reduced performance in their stride length and stride speed in the single task and had made more counting errors in the dual task and still had a higher fall risk. Both the mild and the moderate patients exhibited significant decreases in stride length, stride speed and cadence in the dual task. Was detected a significant correlation between CDT, FAB, and stride speed in the dual task condition. We also found a significant correlation between subtest Similarities, FAB and cadence in the dual task condition. The dual task produced changes in the kinematic parameters of gait for the mild and moderate AD patients and the gait alterations are related to frontal cognitive functions, particularly executive functions.

Plasma Phosphatidylethanolamine and Triacylglycerol Fatty Acid Concentrations are Altered in Major Depressive Disorder Patients with Seasonal Pattern.

PubMed

Otoki, Yurika; Hennebelle, Marie; Levitt, Anthony J; Nakagawa, Kiyotaka; Swardfager, Walter; Taha, Ameer Y

2017-06-01

Disturbances in peripheral and brain lipid metabolism, including the omega-3 fatty acid docosahexaenoic acid (DHA), have been reported in major depressive disorder (MDD). However, these changes have yet to be confirmed in MDD with seasonal pattern (MDD-s), a subtype of recurrent MDD. The present exploratory study quantified plasma plasmalogen and diacyl-phospholipid species, and fatty acids within total phospholipids, cholesteryl esters, triacylglycerols and free fatty acids in non-medicated MDD-s participants (n = 9) during euthymia in summer or fall, and during depression in winter in order to screen for potential high sensitivity lipid biomarkers. Triacylglycerol alpha-linolenic acid concentration was significantly decreased, and myristoleic acid concentration was significantly increased, during winter depression compared to summer-fall euthymia. 1-stearyl-2-docosahexaenoyl-sn-glycero-3-phosphoethanolamine, a diacyl-phospholipid containing stearic acid and DHA, was significantly decreased in winter depression. Concentrations of cholesteryl ester oleic acid and several polyunsaturated fatty acids between summer/fall and winter increased in proportion to the increase in depressive symptoms. The observed changes in lipid metabolic pathways in winter-type MDD-s offer new promise for lipid biomarker development.

An evaluation of satellite data for estimating the area of small forestland in the southern lower peninsula of Michigan. Ph.D. Thesis

NASA Technical Reports Server (NTRS)

Karteris, M. A. (Principal Investigator)

1980-01-01

A winter black and white band 5, a winter color, a fall color, and a diazo color composite of the fall scene were used to assess the use and potential of LANDSAT images for mapping and estimating acreage of small scattered forest tracts in Barry County, Michigan. Forests as small as 2.5 acres were mapped from each LANDSAT data source. The maps for each image were compared with an available forest-type map. Mapping errors detected were categorized as boundary and identification errors. The most frequently misclassified areas were agriculture lands, treed-bogs, brushlands and lowland and mixed hardwood stands. Stocking level affected interpretation more than stand size. The overall level of the interpretation performance was expressed through the estimation of classification, interpretation, and mapping accuracies. These accuracies ranged from 74 between 74% and 98%. Considering errors, accuracy, and cost, winter color imagery is the best LANDSAT alternative for mapping small forest tracts. However, since the availability of cloud-free winter images of the study area is significantly lower than images for other seasons, a diazo enhanced image of a fall scene is recommended as the best next best alternative.

Bone-eating worms from the Antarctic: the contrasting fate of whale and wood remains on the Southern Ocean seafloor

PubMed Central

Glover, Adrian G.; Wiklund, Helena; Taboada, Sergio; Avila, Conxita; Cristobo, Javier; Smith, Craig R.; Kemp, Kirsty M.; Jamieson, Alan J.; Dahlgren, Thomas G.

2013-01-01

We report the results from the first experimental study of the fate of whale and wood remains on the Antarctic seafloor. Using a baited free-vehicle lander design, we show that whale-falls in the Antarctic are heavily infested by at least two new species of bone-eating worm, Osedax antarcticus sp. nov. and Osedax deceptionensis sp. nov. In stark contrast, wood remains are remarkably well preserved with the absence of typical wood-eating fauna such as the xylophagainid bivalves. The combined whale-fall and wood-fall experiment provides support to the hypothesis that the Antarctic circumpolar current is a barrier to the larvae of deep-water species that are broadly distributed in other ocean basins. Since humans first started exploring the Antarctic, wood has been deposited on the seafloor in the form of shipwrecks and waste; our data suggest that this anthropogenic wood may be exceptionally well preserved. Alongside the new species descriptions, we conducted a comprehensive phylogenetic analyses of Osedax, suggesting the clade is most closely related to the frenulate tubeworms, not the vestimentiferans as previous reported. PMID:23945684

A Bibliography of Packet Radio Literature.

DTIC Science & Technology

1984-03-01

r r* C.C.4. W . . . . . . . . .. . . . Gafni, E. and D. Bertsekas, "Distributed Algorithms for Generating Loop-Free Routes in Networks with Frequently...December 1980). Leiner, B., K. Klemba, and J. Tornow , "Packet Radio Networking," Computer World, pp. 26-37, 30, (September 27, 1982). Liu, J...34Distributed Routing and Relay Management in Mobile Packet Radio Networks," Proceedings IEEE COMPCON Fall 󈨔, p. 235-243 (1980). MacGregor, W ., J. Westcott, and

DIME Participants Prepare Experiment Rig

NASA Technical Reports Server (NTRS)

2002-01-01

Students prepare their experiment apparatus for free-fall during the second Dropping in a Microgravity Environment (DIME) competition held April 23-25, 2002, at NASA's Glenn Research Center. Competitors included two teams from Sycamore High School, Cincinnati, OH, and one each from Bay High School, Bay Village, OH, and COSI Academy, Columbus, OH. DIME is part of NASA's education and outreach activities. Details are on line at http://microgravity.grc.nasa.gov/DIME_2002.html.

Tail Separation and Density Effects on the Underwater Trajectory of the JDAM

DTIC Science & Technology

2009-12-01

countermeasure technologies that fulfills this criteria—the use of the Joint Direct Attack Munition (JDAM) to clear a minefield. It updates the general...physics-based, six degrees of freedom model, STRIKE35, to predict the three-dimensional, free-fall trajectory and orientation of a MK-84 bomb...simulating the JDAM) through a water column. It accurately predicts the final detonation position relative to an underwater mine in the very shallow

Cathodic Protection of Hot Water Tanks at Fort Sill

DTIC Science & Technology

2007-06-01

should be flat against the material. Bent rivets will fail under stress . Especially note condition of Dee Ring rivets and Dee Ring metal wear pads...free fall distance. Also, to be stressed are the importance of inspections prior to use, the limitations of the equipment, and unique conditions at...devices during the force test; d. Caution statements on critical use limitations; e. Application limits; f. Proper hook -up, anchoring and tie-off

A Public Voice...'92. America's Role in the World. Energy Options. The Boundaries of Free Speech. A Report from the National Issues Forums, Fall & Winter 1991-1992.

ERIC Educational Resources Information Center

National Issues Forums, Dayton, OH.

This document reports on the tenor and outcomes of the National Issues Forums held in 1991-92 on three issues. The report draws upon three resources: short participant questionnaires, descriptions from groups' convenors, and detailed analysis of the taped proceedings of 10 groups. The report is organized in three sections, each consisting of a…

Running on Empty: Schools Cope with the Roller-Coaster World of Cost Run-Ups and Budget Let-Downs

ERIC Educational Resources Information Center

LaFee, Scott

2009-01-01

Public education is like riding a roller-coaster, except that in education the thrill tends to come on the way up, when the economy is flying high, and funding is flush and the future feels as bracing as the wind rushing past. However, this is not one of those times. The economy seems to be almost in free fall. Optimism plummets with each…

Military Free Fall Scheduling And Manifest Optimization Model

DTIC Science & Technology

2016-12-01

engines running waiting for the next student load. The annual blade hour cost, which consists of fuel, maintenance, and personnel, is $5.6M for FY-16...tarmac with engines running waiting for the next student load (J. Enke, personal communication, 2016). The annual blade hour cost, which consists of...33 Scenario 2 Nonstandard Run #1 C-27 Two Passes per Lift .......................34 Table 9. xii THIS PAGE INTENTIONALLY LEFT BLANK xiii

Force Reconnaissance: A Key Enabler in the Marine Air Ground Task Force and Beyond

DTIC Science & Technology

2012-03-13

round Task Force Advance Force Operations, Deep Reconnaissance, Military Free Fall (MFF), Marine Combatar t Diver ( MCD ), Joint Terminal Attack...Marine Division. These early years focused on developing the doctrine and insertion skills became legendary in the crucible of South East Asia , and...potential for regional powers to threaten critical U.S. interests. Areas of particular concern in the QDR are the Middle East and Asia .41 The United

Simple Examples of the Interpretation of Changes in Kinetic and Potential Energy Under Galilean Transformations

NASA Astrophysics Data System (ADS)

Ginsberg, Edw. S.

2018-02-01

The compatibility of the Newtonian formulation of mechanical energy and the transformation equations of Galilean relativity is demonstrated for three simple examples of motion treated in most introductory physics courses (free fall, a frictionless inclined plane, and a mass/spring system). Only elementary concepts and mathematics, accessible to students at that level, are used. Emphasis is on pedagogy and concepts related to the transformation properties of potential energy.

Newton in Space

NASA Technical Reports Server (NTRS)

Herbert, Dexter (Editor)

1992-01-01

In this 'Liftoff to Learning' series video, astronauts (Charles Veach, Gregory Harbaugh, Donald McMonagle, Michael Coats, L. Blaine Hammond, Guion Bluford, Richard Hieb) from the STS-39 Mission use physical experiments and computer animation to explain how weightlessness and gravity affects everything and everyone onboard the Space Shuttle. The physics behind the differences between weight and mass, and the concepts of 'free fall', are demonstrated along with explanations and experiments of Sir Issac Newton's three laws of motion.

Using Galileo's Own Words in the Physics Classroom

NASA Astrophysics Data System (ADS)

Garber, Gary

2009-10-01

After years of discussing Galileo using secondary sources, I decided to have my students use Galileo's writings as a primary source of information in their lab reports. The advancements of Google Books and the internet has made it possible for all students to read Aristotle, Galileo, and Newton when exploring the nature of free fall kinematics. I will present links and suggested passages from several sources including Galileo's Dialogues Concerning Two New Sciences.

Acoustic Excitation of Liquid Fuel Droplets and Coaxial Jets

DTIC Science & Technology

2009-01-01

would also like to acknowledge the support of the NASA Microgravity Combustion program which made possible the completion of this research and Maj...fuels exposed to different acoustic excitation conditions in a laboratory environment and during free-fall (microgravity) conditions in a NASA drop tower...then sent to two amplifiers, one for each piezo-siren. The amplifiers were a Krohn-Hite (model 7500) and a Trek (model PZD2000A), which amplified the

Midwestern United States as seen from STS-58

NASA Image and Video Library

1993-10-30

STS058-102-018 (18 Oct-1 Nov 1993) --- A cloud-free, wide-angle view from above western Tennessee to the northern edge of Lake Michigan. The view extends from Saint Louis, Missouri near the lower left-hand corner, past Evansville, Indiana and Louisville, Kentucky to Cincinnati, Ohio. A range of hills covered by trees in Fall foliage extends from the Ohio River toward Lake Michigan, ending just southwest of Indianapolis, Indiana.

LISA Pathfinder first results

NASA Astrophysics Data System (ADS)

Vetrugno, D.

LISA Pathfinder (LPF) is an in-flight technological demonstrator designed and launched to prove the feasibility of sub-femto-g free fall of kilo-sized test masses (TM), an essential ingredient for the future gravitational wave observatory from space. Half a year after launch, the first results are available and show an incredibly well-performing instrument. The results represent a first and important step towards the long awaited construction and launch of LISA, the Laser Interferometer Space Antenna.

America, Linearly Cyclical

DTIC Science & Technology

2013-05-10

Article Speech Pape.r Presentation Poster Thesis/Dissertation Book Other : Check all that apply (For Communications Purposes): 0 CRADA {Cooperative...Is America succeeding in her goal to break free of this wheel of fortune, or is she falling and failing like every other civilization in history...34Such a wheel of life symbolized the wandering of the soul from a higher existence to a lower, from a lower to a higher, many times repeated, as on a

DOE Office of Scientific and Technical Information (OSTI.GOV)

Oliver, R.; Soler, R.; Terradas, J.

Observations of active regions and limb prominences often show cold, dense blobs descending with an acceleration smaller than that of free fall. The dynamics of these condensations falling in the solar corona is investigated in this paper using a simple fully ionized plasma model. We find that the presence of a heavy condensation gives rise to a dynamical rearrangement of the coronal pressure that results in the formation of a large pressure gradient that opposes gravity. Eventually this pressure gradient becomes so large that the blob acceleration vanishes or even points upward. Then, the blob descent is characterized by anmore » initial acceleration phase followed by an essentially constant velocity phase. These two stages can be identified in published time-distance diagrams of coronal rain events. Both the duration of the first stage and the velocity attained by the blob increase for larger values of the ratio of blob to coronal density, for larger blob mass, and for smaller coronal temperature. Dense blobs are characterized by a detectable density growth (up to 60% in our calculations) and by a steepening of the density in their lower part, that could lead to the formation of a shock. They also emit sound waves that could be detected as small intensity changes with periods of the order of 100 s and lasting between a few and about 10 periods. Finally, the curvature of falling paths with large radii is only relevant when a very dense blob falls along inclined magnetic field lines.« less

Fabrication of Defect-Free Ferroelectric Liquid Crystal Displays Using Photoalignment and Their Electrooptic Performance

NASA Astrophysics Data System (ADS)

Kurihara, Ryuji; Furue, Hirokazu; Takahashi, Taiju; Yamashita, Tomo-o; Xu, Jun; Kobayashi, Shunsuke

2001-07-01

A photoalignment technique has been utilized for fabricating zigzag-defect-free ferroelectric liquid crystal displays (FLCDs) using polyimide RN-1199, -1286, -1266 (Nissan Chem. Ind.) and adopting oblique irradiation of unpolarized UV light. A rubbing technique was also utilized for comparison. It is shown that among these polyimide materials, RN-1199 is the best for fabricating defect-free cells with C-1 uniform states, but RN-1286 requires low energy to produce a photoaligned FLC phase. We have conducted an analytical investigation to clarify the conditions for obtaining zigzag-defect-free C-1 states, and it is theoretically shown that zigzag-defect-free C-1 state is obtained using a low azimuthal anchoring energy at a low pretilt angle, while a zigzag-defect-free C-2 state is obtained by increasing azimuthal anchoring energy above a critical value, also at a low pretilt angle. The estimated critical value of the azimuthal anchoring energy at which a transition from the C-1 state to the C-2 state occurs is 3×10-6 J/m2 for the FLC material FELIX M4654/100 (Clariant) used in this research; this value is shown to fall in a favorable range which is measured in an independent experiment.

Physics Leads to Free Elections in the Nuclear Age.

NASA Astrophysics Data System (ADS)

Synek, Miroslav

2001-10-01

------------- Complex historical development on our planet, utilizing the knowledge of physics, has reached a powerful technology of nuclear intercontinental missiles, conceivably controllable through a computerized "push-button". Whenever this technology falls under the control of an irresponsible, miscalculating, or, insane dictator, with sufficiently powerful means of a huge, mass-produced, nuclear-missile built-up, anywhere on our planet, the very survival of all humanity on our planet could be threatened. Therefore, it is a historical urgency that this technology be under the control by a government of the people, by the people and for the people, based on a sufficiently reliable system of free elections, in any country on our planet, wherever and whenever a total nuclear holocaust could originate.

Trihalomethane and nonpurgeable total organic-halide formation potentials of the Mississippi river

USGS Publications Warehouse

Rathbun, R.E.

1996-01-01

Trihalomethane and nonpurgeable total organic-hallide formation potentials were determined for water samples from 12 sites along the Mississippi River from Minneapolis, MN, to New Orleans, LA, for the summer and fall of 1991 and the spring of 1992. The formation potentials increased with distance upstream, approximately paralleling the increase of the dissolved organic- carbon concentration. The pH and the dissolved organic-carbon and free- chlorine concentrations were significant variables in the prediction of the formation potentials. The trihalomethane formation potential increased as the pH increased, whereas the nonpurgeable total organic-halide formation potential decreased. All formation potentials increased as the dissolved organic-carbon and free-chlorine concentrations increased, with the dissolved organic-carbon concentration having a much greater effect.

Free tax assistance and the earned income tax credit: vital resources for social workers and low-income families.

PubMed

Lim, Younghee; DeJohn, Tara V; Murray, Drew

2012-04-01

As the United States' economy continues to experience challenges, more families at or near the poverty level fall prey to predatory financial practices. Their vulnerability to these operations is increased by a lack of knowledge of asset-building resources and alternative financial services. This article focuses on Volunteer Income Tax Assistance (VITA)--a free income tax preparation program, which is a vital resource available to low-income families. Unfortunately, VITA is largely underused and often unknown to economically strained families and to the social workers and other professionals to whom these families turn for assistance. This article concludes with policy and practice implications for social workers and other professionals engaged in providing services to financially vulnerable families.

High Power Amplifier and Power Supply

NASA Technical Reports Server (NTRS)

Duong, Johnny; Stride, Scot; Harvey, Wayne; Haque, Inam; Packard, Newton; Ng, Quintin; Ispirian, Julie Y.; Waian, Christopher; Janes, Drew

2008-01-01

A document discusses the creation of a high-voltage power supply (HVPS) that is able to contain voltages up to -20 kV, keep electrical field strengths to below 200 V/mil (approximately equal to 7.87 kV/mm), and can provide a 200-nanosecond rise/fall time focus modulator swinging between cathode potential of 16.3 kV and -19.3 kV. This HVPS can protect the 95-GHz, pulsed extended interaction klystron (EIK) from arcs/discharges from all sources, including those from within the EIK fs vacuum envelope. This innovation has a multi-winding pulse transformer design, which uses new winding techniques to provide the same delays and rise/fall times (less than 10 nanoseconds) at different potential levels ranging from -20 kV to -16 kV. Another feature involves a high-voltage printed-wiring board that was corona-free at -20 kV DC with a 3- kV AC swing. The corona-free multilayer high-voltage board is used to simulate fields of less than 200 V/mil (approximately equal to 7.87 kV/mm) at 20 kV DC. Drive techniques for the modulator FETs (field-effect transistors) (four to 10 in a series) were created to change states (3,000-V swing) without abrupt steps, while still maintaining required delays and transition times. The packing scheme includes a potting mold to house a ten-stage modulator in the space that, in the past, only housed a four-stage modulator. Problems keeping heat down were solved using aluminum oxide substrate in the high-voltage section to limit temperature rise to less than 10 while withstanding -20 kV DC voltage and remaining corona-free.

Effects of exercise improves muscle strength and fat mass in patients with high fracture risk: A randomized control trial.

PubMed

Chan, Ding-Cheng; Chang, Chirn-Bin; Han, Der-Sheng; Hong, Cian-Hui; Hwang, Jawl-Shan; Tsai, Keh-Sung; Yang, Rong-Sen

2017-10-26

The deterioration of the musculoskeletal system imposes significant impact on physical activity. Exercise is an important strategy which minimizes these changes. It is not clear which type of exercise provides better improvement on low physical performance, low muscle mass and low strength of sarcopenia. We aim to develop an integrated care (IC) model and compare its relative efficacy in limb fat free mass, muscle strength, and physical performance with low extremities exercise (LEE) in community dwelling older adults with high risk of fractures (Fracture Risk Assessment Tool (FRAX ® )) ≧3% for hip fracture, ≧20% for major osteoporotic fracture or 1-min osteoporosis risk test (≧1 point) or fall (≧2 falls in previous year). Patients were assigned randomized to participate in either IC or LEE group (n = 55 each) for 3 months. All participants received education including home-based exercise. The IC group consisted of different modalities of exercise while the LEE group performed machine-based low extremities exercise. Fat free mass, muscle strength, and physical performance were measured at their baseline and 3-months follow-up. Mean age was 73.8 ± 7 years with 69.1% women. Entire cohort demonstrated significant increment in fat free mass, muscle strength (4 indicators) and physical performance (3 indicators). However, between group differences were not significant. With regular supervise exercise; both groups are equally effective in decreasing fat mass and increasing physical performance, muscle mass and strength. However, the IC group required fewer resources and thus more financially feasible in a community setting. Copyright © 2017. Published by Elsevier B.V.

The Sleep/Wake Cycle is Directly Modulated by Changes in Energy Balance.

PubMed

Collet, Tinh-Hai; van der Klaauw, Agatha A; Henning, Elana; Keogh, Julia M; Suddaby, Diane; Dachi, Sekesai V; Dunbar, Síle; Kelway, Sarah; Dickson, Suzanne L; Farooqi, I Sadaf; Schmid, Sebastian M

2016-09-01

The rise in obesity has been paralleled by a decline in sleep duration in epidemiological studies. However, the potential mechanisms linking energy balance and the sleep/wake cycle are not well understood. We aimed to examine the effects of manipulating energy balance on the sleep/wake cycle. Twelve healthy normal weight men were housed in a clinical research facility and studied at three time points: baseline, after energy balance was disrupted by 2 days of caloric restriction to 10% of energy requirements, and after energy balance was restored by 2 days of ad libitum/free feeding. Sleep architecture, duration of sleep stages, and sleep-associated respiratory parameters were measured by polysomnography. Two days of caloric restriction significantly increased the duration of deep (stage 4) sleep (16.8% to 21.7% of total sleep time; P = 0.03); an effect which was entirely reversed upon free feeding (P = 0.01). Although the apnea-hypopnea index stayed within the reference range (< 5 events per hour), it decreased significantly from caloric restriction to free feeding (P = 0.03). Caloric restriction was associated with a marked fall in leptin (P < 0.001) and insulin levels (P = 0.002). The fall in orexin levels from baseline to caloric restriction correlated positively with duration of stage 4 sleep (Spearman rho = 0.83, P = 0.01) and negatively with the number of awakenings in caloric restriction (Spearman rho = -0.79, P = 0.01). We demonstrate that changes in energy homeostasis directly and reversibly impact on the sleep/wake cycle. These findings provide a mechanistic framework for investigating the association between sleep duration and obesity risk. © 2016 Associated Professional Sleep Societies, LLC.

Gravitational attraction until relativistic equipartition of internal and translational kinetic energies

NASA Astrophysics Data System (ADS)

Bulyzhenkov, I. E.

2018-02-01

Translational ordering of the internal kinematic chaos provides the Special Relativity referents for the geodesic motion of warm thermodynamical bodies. Taking identical mathematics, relativistic physics of the low speed transport of time-varying heat-energies differs from Newton's physics of steady masses without internal degrees of freedom. General Relativity predicts geodesic changes of the internal heat-energy variable under the free gravitational fall and the geodesic turn in the radial field center. Internal heat variations enable cyclic dynamics of decelerated falls and accelerated takeoffs of inertial matter and its structural self-organization. The coordinate speed of the ordered spatial motion takes maximum under the equipartition of relativistic internal and translational kinetic energies. Observable predictions are discussed for verification/falsification of the principle of equipartition as a new basic for the ordered motion and self-organization in external fields, including gravitational, electromagnetic, and thermal ones.

Observed variations in U.S. frost timing linked to atmospheric circulation patterns

NASA Astrophysics Data System (ADS)

Strong, Courtenay; McCabe, Gregory J.

2017-05-01

Several studies document lengthening of the frost-free season within the conterminous United States (U.S.) over the past century, and report trends in spring and fall frost timing that could stem from hemispheric warming. In the absence of warming, theory and case studies link anomalous frost timing to atmospheric circulation anomalies. However, recent efforts to relate a century of observed changes in U.S. frost timing to various atmospheric circulations yielded only modest correlations, leaving the relative importance of circulation and warming unclear. Here, we objectively partition the U.S. into four regions and uncover atmospheric circulations that account for 25-48% of spring and fall-frost timing. These circulations appear responsive to historical warming, and they consistently account for more frost timing variability than hemispheric or regional temperature indices. Reliable projections of future variations in growing season length depend on the fidelity of these circulation patterns in global climate models.

Observed variations in U.S. frost timing linked to atmospheric circulation patterns

USGS Publications Warehouse

Strong, Courtenay; McCabe, Gregory J.

2017-01-01

Several studies document lengthening of the frost-free season within the conterminous United States (U.S.) over the past century, and report trends in spring and fall frost timing that could stem from hemispheric warming. In the absence of warming, theory and case studies link anomalous frost timing to atmospheric circulation anomalies. However, recent efforts to relate a century of observed changes in U.S. frost timing to various atmospheric circulations yielded only modest correlations, leaving the relative importance of circulation and warming unclear. Here, we objectively partition the U.S. into four regions and uncover atmospheric circulations that account for 25–48% of spring and fall-frost timing. These circulations appear responsive to historical warming, and they consistently account for more frost timing variability than hemispheric or regional temperature indices. Reliable projections of future variations in growing season length depend on the fidelity of these circulation patterns in global climate models.

Can MOND type hypotheses be tested in a free fall laboratory environment?

NASA Astrophysics Data System (ADS)

Das, Saurya; Patitsas, S. N.

2013-05-01

The extremely small accelerations of objects required for the onset of modified Newtonian dynamics, or modified Newtonian dynamics (MOND), makes testing the hypothesis in conventional terrestrial laboratories virtually impossible. This is due to the large background acceleration of Earth, which is transmitted to the acceleration of test objects within an apparatus. We show, however, that it may be possible to test MOND-type hypotheses with experiments using a conventional apparatus capable of tracking very small accelerations of its components but performed in locally inertial frames such as artificial satellites and other freely falling laboratories. For example, experiments involving an optical interferometer or a torsion balance in these laboratories would show nonlinear dynamics and displacement amplitudes larger than expected. These experiments may also be able to test potential violations of the strong equivalence principle by MOND and to distinguish between its two possible interpretations (modified inertia and modified gravity).

US refining margin trend: austerity continues

DOE Office of Scientific and Technical Information (OSTI.GOV)

Not Available

Should crude oil prices hold near current levels in 1988, US refining margins might improve little, if at all. If crude oil prices rise, margins could blush pink or worse. If they drop, US refiners would still probably not see much margin improvement. In fact, if crude prices fall, they could set off another free fall in products markets and threaten refiner survival. Volatility in refined products markets and low product demand growth are the underlying reasons for caution or pessimism as the new year approaches. Recent directional patterns in refining margins are scrutinized in this issue. This issue alsomore » contains the following: (1) the ED refining netback data for the US Gulf and West Coasts, Rotterdam, and Singapore for late November, 1987; and (2) the ED fuel price/tax series for countries of the Eastern Hemisphere, November, 1987 edition. 4 figures, 6 tables.« less

Levodopa, placebo and rotigotine change biomarker levels for oxidative stress.

PubMed

Muhlack, Siegfried; Kinkel, Manuel; Herrman, Lennard; Müller, Thomas

2017-05-01

Homocysteine increase and glutathione derivative cysteinyl-glycine fall are indirect biomarkers for oxidative stress, for instance due to dopamine D 1 receptor stimulation. To investigate the influence of the D 1 receptor agonists levodopa and rotigotine compared with placebo on homocysteine and cysteinyl-glycine in plasma of patients with Parkinson's disease. Patients received 100 mg levodopa, 4 mg rotigotine or placebo. Cysteinyl-glycine and homocysteine were measured every 30 min over three hours. Homocysteine rose during levodopa- and placebo administration. Rotigotine had no effect. Cysteine-glycine only increased after placebo- but not after levodopa- or rotigotine. Homocysteine elevation results from hepatic and gastrointestinal methylation processes. Transdermal rotigotine circumvents these methylation locations. Turnover of segregated alkyl residuals from rotigotine serves as methyl group donors, which counteract homocysteine increment. The placebo-related cysteinyl-glycine increase results from reduced free radical exposure. Low levodopa dosing and antioxidants in the rotigotine patch matrix prevented cysteinyl-glycine fall.

Observed variations in U.S. frost timing linked to atmospheric circulation patterns.

PubMed

Strong, Courtenay; McCabe, Gregory J

2017-05-23

Several studies document lengthening of the frost-free season within the conterminous United States (U.S.) over the past century, and report trends in spring and fall frost timing that could stem from hemispheric warming. In the absence of warming, theory and case studies link anomalous frost timing to atmospheric circulation anomalies. However, recent efforts to relate a century of observed changes in U.S. frost timing to various atmospheric circulations yielded only modest correlations, leaving the relative importance of circulation and warming unclear. Here, we objectively partition the U.S. into four regions and uncover atmospheric circulations that account for 25-48% of spring and fall-frost timing. These circulations appear responsive to historical warming, and they consistently account for more frost timing variability than hemispheric or regional temperature indices. Reliable projections of future variations in growing season length depend on the fidelity of these circulation patterns in global climate models.

Scale-Free Neural and Physiological Dynamics in Naturalistic Stimuli Processing

PubMed Central

Lin, Amy

2016-01-01

Abstract Neural activity recorded at multiple spatiotemporal scales is dominated by arrhythmic fluctuations without a characteristic temporal periodicity. Such activity often exhibits a 1/f-type power spectrum, in which power falls off with increasing frequency following a power-law function: P(f)∝1/fβ, which is indicative of scale-free dynamics. Two extensively studied forms of scale-free neural dynamics in the human brain are slow cortical potentials (SCPs)—the low-frequency (<5 Hz) component of brain field potentials—and the amplitude fluctuations of α oscillations, both of which have been shown to carry important functional roles. In addition, scale-free dynamics characterize normal human physiology such as heartbeat dynamics. However, the exact relationships among these scale-free neural and physiological dynamics remain unclear. We recorded simultaneous magnetoencephalography and electrocardiography in healthy subjects in the resting state and while performing a discrimination task on scale-free dynamical auditory stimuli that followed different scale-free statistics. We observed that long-range temporal correlation (captured by the power-law exponent β) in SCPs positively correlated with that of heartbeat dynamics across time within an individual and negatively correlated with that of α-amplitude fluctuations across individuals. In addition, across individuals, long-range temporal correlation of both SCP and α-oscillation amplitude predicted subjects’ discrimination performance in the auditory task, albeit through antagonistic relationships. These findings reveal interrelations among different scale-free neural and physiological dynamics and initial evidence for the involvement of scale-free neural dynamics in the processing of natural stimuli, which often exhibit scale-free dynamics. PMID:27822495

Integration of balance and strength training into daily life activity to reduce rate of falls in older people (the LiFE study): randomised parallel trial

PubMed Central

Fiatarone Singh, Maria A; Bundy, Anita; Cumming, Robert G; Manollaras, Kate; O’Loughlin, Patricia; Black, Deborah

2012-01-01

Objectives To determine whether a lifestyle integrated approach to balance and strength training is effective in reducing the rate of falls in older, high risk people living at home. Design Three arm, randomised parallel trial; assessments at baseline and after six and 12 months. Randomisation done by computer generated random blocks, stratified by sex and fall history and concealed by an independent secure website. Setting Residents in metropolitan Sydney, Australia. Participants Participants aged 70 years or older who had two or more falls or one injurious fall in past 12 months, recruited from Veteran’s Affairs databases and general practice databases. Exclusion criteria were moderate to severe cognitive problems, inability to ambulate independently, neurological conditions that severely influenced gait and mobility, resident in a nursing home or hostel, or any unstable or terminal illness that would affect ability to do exercises. Interventions Three home based interventions: Lifestyle integrated Functional Exercise (LiFE) approach (n=107; taught principles of balance and strength training and integrated selected activities into everyday routines), structured programme (n=105; exercises for balance and lower limb strength, done three times a week), sham control programme (n=105; gentle exercise). LiFE and structured groups received five sessions with two booster visits and two phone calls; controls received three home visits and six phone calls. Assessments made at baseline and after six and 12 months. Main outcome measures Primary measure: rate of falls over 12 months, collected by self report. Secondary measures: static and dynamic balance; ankle, knee and hip strength; balance self efficacy; daily living activities; participation; habitual physical activity; quality of life; energy expenditure; body mass index; and fat free mass. Results After 12 months’ follow-up, we recorded 172, 193, and 224 falls in the LiFE, structured exercise, and control groups, respectively. The overall incidence of falls in the LiFE programme was 1.66 per person years, compared with 1.90 in the structured programme and 2.28 in the control group. We saw a significant reduction of 31% in the rate of falls for the LiFE programme compared with controls (incidence rate ratio 0.69 (95% confidence interval 0.48 to 0.99)); the corresponding difference between the structured group and controls was non-significant (0.81 (0.56 to 1.17)). Static balance on an eight level hierarchy scale, ankle strength, function, and participation were significantly better in the LiFE group than in controls. LiFE and structured groups had a significant and moderate improvement in dynamic balance, compared with controls. Conclusions The LiFE programme provides an alternative to traditional exercise to consider for fall prevention. Functional based exercise should be a focus for interventions to protect older, high risk people from falling and to improve and maintain functional capacity. Trial registration Australia and New Zealand Clinical Trials Registry 12606000025538. PMID:22872695

Integration of balance and strength training into daily life activity to reduce rate of falls in older people (the LiFE study): randomised parallel trial.

PubMed

Clemson, Lindy; Fiatarone Singh, Maria A; Bundy, Anita; Cumming, Robert G; Manollaras, Kate; O'Loughlin, Patricia; Black, Deborah

2012-08-07

To determine whether a lifestyle integrated approach to balance and strength training is effective in reducing the rate of falls in older, high risk people living at home. Three arm, randomised parallel trial; assessments at baseline and after six and 12 months. Randomisation done by computer generated random blocks, stratified by sex and fall history and concealed by an independent secure website. Residents in metropolitan Sydney, Australia. Participants aged 70 years or older who had two or more falls or one injurious fall in past 12 months, recruited from Veteran's Affairs databases and general practice databases. Exclusion criteria were moderate to severe cognitive problems, inability to ambulate independently, neurological conditions that severely influenced gait and mobility, resident in a nursing home or hostel, or any unstable or terminal illness that would affect ability to do exercises. Three home based interventions: Lifestyle integrated Functional Exercise (LiFE) approach (n=107; taught principles of balance and strength training and integrated selected activities into everyday routines), structured programme (n=105; exercises for balance and lower limb strength, done three times a week), sham control programme (n=105; gentle exercise). LiFE and structured groups received five sessions with two booster visits and two phone calls; controls received three home visits and six phone calls. Assessments made at baseline and after six and 12 months. Primary measure: rate of falls over 12 months, collected by self report. Secondary measures: static and dynamic balance; ankle, knee and hip strength; balance self efficacy; daily living activities; participation; habitual physical activity; quality of life; energy expenditure; body mass index; and fat free mass. After 12 months' follow-up, we recorded 172, 193, and 224 falls in the LiFE, structured exercise, and control groups, respectively. The overall incidence of falls in the LiFE programme was 1.66 per person years, compared with 1.90 in the structured programme and 2.28 in the control group. We saw a significant reduction of 31% in the rate of falls for the LiFE programme compared with controls (incidence rate ratio 0.69 (95% confidence interval 0.48 to 0.99)); the corresponding difference between the structured group and controls was non-significant (0.81 (0.56 to 1.17)). Static balance on an eight level hierarchy scale, ankle strength, function, and participation were significantly better in the LiFE group than in controls. LiFE and structured groups had a significant and moderate improvement in dynamic balance, compared with controls. The LiFE programme provides an alternative to traditional exercise to consider for fall prevention. Functional based exercise should be a focus for interventions to protect older, high risk people from falling and to improve and maintain functional capacity. Australia and New Zealand Clinical Trials Registry 12606000025538.

Predicting Active Duty Air Force Pilot Attrition Given an Anticipated Increase in Major Airline Pilot Hiring

DTIC Science & Technology

2015-01-01

of the RAND Corporation. CHILDREN AND FAMILIES EDUCATION AND THE ARTS ENERGY AND ENVIRONMENT HEALTH AND HEALTH CARE INFRASTRUCTURE AND...of service changes. This time, the landscape is different. As such, this dissertation intends to illustrate the effect that looming increases in...Accounting Office, 1999a; Grier, 1998). This prediction was bolstered by a free -falling ACP take rate, which ended the year at 26 percent. In a September

Design of a Helmet Liner for Improved Low Velocity Impact Protection

DTIC Science & Technology

2013-05-01

FIGURE 14. MONORAIL DROP TEST WITH DOT-SIZE C HEADFORM AND HEMISPHERICAL ANVIL ........................... 14  FIGURE 15. ACH PAD CONFIGURATION. LEFT...materials. In this project, the monorail drop test device, used for the helmeted headform drop test, was modified for material testing as shown in Figure...a guided free fall drop test using a monorail drop test apparatus as shown in Figure 14. All helmets tested in this study were ACH-Size Large and

Source Amplitudes of NTS Explosions Inferred from Rayleigh Waves at Albuquerque and Tucson

DTIC Science & Technology

1978-06-01

explosions almost always cause spallation near the free surface (e.g., Eisler and Chilton, 1964). When the spalled material falls back to the surface...spall closure), some impulse is delivered and a large signal associated with spall closure can often be observed on near- field recordings (e.g., Eisler ...made for the extent of the spall region ( Eisler and Chilton, 1964; Viecelli, 1973; Sobel, 1978). Viecelli (1973) studied the data for six explosions

Air Force Academy Aeronautics Digest - Fall/Winter 1980.

DTIC Science & Technology

1981-05-01

Crandall # _2EXAMINING A RULE OF THUMB FOR THE RELATION BETWEEN CAMBER AND 21 ZERO -LIFT ANGLE OF ATTACK,S----E.J. Jumper / EXPERIMENTAL AERODYNAMIC...slow- ing the fluid velocity to zero without loss. Static pressure is the pressure exerted on an aerodynamic surface parallel to the free stream...it is zero at the vor- tex center. Figure 2 shows the velocity distribution of a vortex with a viscous core 0. rt r Figure 2. Fluid Velocity Versus

The Proposed U.S.-South Korea Free Trade Agreement (KORUS FTA): Provisions and Implications

DTIC Science & Technology

2009-04-20

to which household purchasing power is affected by the country’s economic crisis. (See Appendix A for additional details.) Rice South Korean...have restricted U.S. fruit and vegetable exports. This new standing committee potentially could be used as the venue to attempt to resolve future SPS...to open in 2009.32 Falling imports from Korea probably were affected by a general softening of the U.S. market. U.S. exporters, including South

The Proposed U.S.-South Korea Free Trade Agreement (KORUS FTA): Provisions and Implications

DTIC Science & Technology

2009-06-17

purchasing power is affected by the country’s economic crisis. (See Appendix A for additional details.) Rice South Korean negotiators succeeded in... fruit and vegetable exports. This new standing committee potentially could be used as the venue to attempt to resolve future SPS disputes, taking...some imports. Kia is also building a U.S. assembly plant expected to open in 2009.32 Falling imports from Korea probably were affected by a general

JPRS Report, Near East & South Asia

DTIC Science & Technology

1989-03-28

Arab Nuclear, CBW Capabilities, Use [Cairo AL-SHA’B 24, 31 Jan ] 3 Egyptian Writer Sees North Sudanese Urging Secession of South [Cairo AL...Economic Difficulties in West Bank, Gaza Described [Al-Dammam AL-1QTISAD WA AL-’AMAL Jan ] 18 EGYPT Port Sa’id Faces Economic, Development...Troubles 20 Free Zone in Decline [ AKHBAR AL-YA WM 3 Dec] 20 Officials, Businessmen Try To Counter Falling Dollar [ AKHBAR AL-YA WM 3 Dec] 21 ISRAEL

Calculation of Moment Matrix Elements for Bilinear Quadrilaterals and Higher-Order Basis Functions

DTIC Science & Technology

2016-01-06

methods are known as boundary integral equation (BIE) methods and the present study falls into this category. The numerical solution of the BIE is...iterated integrals. The inner integral involves the product of the free-space Green’s function for the Helmholtz equation multiplied by an appropriate...Website: http://www.wipl-d.com/ 5. Y. Zhang and T. K. Sarkar, Parallel Solution of Integral Equation -Based EM Problems in the Frequency Domain. New

Counter-rotating accretion discs

NASA Astrophysics Data System (ADS)

Dyda, S.; Lovelace, R. V. E.; Ustyugova, G. V.; Romanova, M. M.; Koldoba, A. V.

2015-01-01

Counter-rotating discs can arise from the accretion of a counter-rotating gas cloud on to the surface of an existing corotating disc or from the counter-rotating gas moving radially inwards to the outer edge of an existing disc. At the interface, the two components mix to produce gas or plasma with zero net angular momentum which tends to free-fall towards the disc centre. We discuss high-resolution axisymmetric hydrodynamic simulations of viscous counter-rotating discs for the cases where the two components are vertically separated and radially separated. The viscosity is described by an isotropic α-viscosity including all terms in the viscous stress tensor. For the vertically separated components, a shear layer forms between them and the middle part of this layer free-falls to the disc centre. The accretion rates are increased by factors of ˜102-104 over that for a conventional disc rotating in one direction with the same viscosity. The vertical width of the shear layer and the accretion rate are strongly dependent on the viscosity and the mass fraction of the counter-rotating gas. In the case of radially separated components where the inner disc corotates and the outer disc rotates in the opposite direction, a gap between the two components opens and closes quasi-periodically. The accretion rates are ≳25 times larger than those for a disc rotating in one direction with the same viscosity.

[The role played by the parietooccipital cortex in the process of sensory-motor integration: an electroencephalographic study].

PubMed

Machado, S; Cunha, M; Portella, C E; Silva, J G; Velasques, B; Bastos, V H; Basile, L; Cagy, M; Piedade, R A; Ribeiro, P

A fundamental aspect of planning future actions is the performance and control of motor tasks. This behaviour is done through sensory-motor integration. To explain the electrophysiological mechanisms in the cortex (modifications to the alpha band) that are involved in anticipatory actions when individuals have to catch a free-falling object. The sample was made up of 20 healthy subjects of both sexes (11 males and 9 females) with ages ranging between 25 and 40 years (32.5 +/- 7.5) who were free of mental or physical diseases (previous medical history); the subjects were right-handed (Edinburgh Inventory) and were not taking any psychoactive or psychotropic substances at the time of the study. The experiment consisted in a task in which subjects had to catch freely falling objects. The experiment was made up of six blocks of 15 tests, each of which lasted 2 minutes and 30 seconds, with a break of one minute between blocks. Data were captured by means of a quantitative electroencephalogram two seconds before and two seconds after each ball was dropped. An interaction of the factors moment and position was only observed for the right parietooccipital cortex, in the combination of electrodes P4-O2. These findings suggest that the right parietooccipital cortex plays an important role in increasing expectation and swiftness in the processes of preparing for a motor task.

Particle-Associated Differ from Free-Living Bacteria in Surface Waters of the Baltic Sea

PubMed Central

Rieck, Angelika; Herlemann, Daniel P. R.; Jürgens, Klaus; Grossart, Hans-Peter

2015-01-01

Many studies on bacterial community composition (BCC) do not distinguish between particle-associated (PA) and free-living (FL) bacteria or neglect the PA fraction by pre-filtration removing most particles. Although temporal and spatial gradients in environmental variables are known to shape BCC, it remains unclear how and to what extent PA and FL bacterial diversity responds to such environmental changes. To elucidate the BCC of both bacterial fractions related to different environmental settings, we studied surface samples of three Baltic Sea stations (marine, mesohaline, and oligohaline) in two different seasons (summer and fall/winter). Amplicon sequencing of the 16 S rRNA gene revealed significant differences in BCC of both bacterial fractions among stations and seasons, with a particularly high number of PA operational taxonomic units (OTUs at genus-level) at the marine station in both seasons. “Shannon and Simpson indices” showed a higher diversity of PA than FL bacteria at the marine station in both seasons and at the oligohaline station in fall/winter. In general, a high fraction of bacterial OTUs was found exclusively in the PA fraction (52% of total OTUs). These findings indicate that PA bacteria significantly contribute to overall bacterial richness and that they differ from FL bacteria. Therefore, to gain a deeper understanding on diversity and dynamics of aquatic bacteria, PA and FL bacteria should be generally studied independently. PMID:26648911

Teaching weight to explicitly address language ambiguities and conceptual difficulties

NASA Astrophysics Data System (ADS)

Taibu, Rex; Schuster, David; Rudge, David

2017-06-01

Language ambiguities in concept meanings can exacerbate student learning difficulties and conceptual understanding of physics concepts. This is especially true for the concept of "weight," which has multiple meanings in both scientific and everyday usage. The term weight has been defined in several different ways, with nuances, but in textbooks and teaching the term is almost always defined in one of two ways: operationally either as the contact force between an object and a measuring scale or as the gravitational force on an object due to some other body such as Earth. The use of the same name for different concepts leads to much confusion, especially in accelerating situations, and to conflicting notions of "weightlessness" in free fall situations. In the present paper, we share an innovative approach that initially avoids the term weight entirely while teaching the physics of each situation, and then teaches the language ambiguities explicitly. We developed an instructional module with this approach and implemented it over two terms in three sections of an introductory physics course for preservice elementary teachers. Learning gains for content understanding were assessed using pretests and post-tests. Participants achieved remarkably high gains for both static and accelerating situations. Surveys pre- and postinstruction showed substantially improved appreciation of language issues and ambiguities associated with weight, weightlessness, and free fall. Interviews with instructors teaching the module provided additional insight into the advantages and teaching demands of the new approach.

LISA on Table: an optical simulator for LISA

NASA Astrophysics Data System (ADS)

Halloin, H.; Jeannin, O.; Argence, B.; Bourrier, V.; de Vismes, E.; Prat, P.

2017-11-01

LISA, the first space project for detecting gravitational waves, relies on two main technical challenges: the free falling masses and an outstanding precision on phase shift measurements (a few pm on 5 Mkm in the LISA band). The technology of the free falling masses, i.e. their isolation to forces other than gravity and the capability for the spacecraft to precisely follow the test masses, will soon be tested with the technological LISA Pathfinder mission. The performance of the phase measurement will be achieved by at least two stabilization stages: a pre-stabilisation of the laser frequency at a level of 10-13 (relative frequency stability) will be further improved by using numerical algorithms, such as Time Delay Interferometry, which have been theoretically and numerically demonstrated to reach the required performance level (10-21). Nevertheless, these algorithms, though already tested with numerical model of LISA, require experimental validation, including `realistic' hardware elements. Such an experiment would allow to evaluate the expected noise level and the possible interactions between subsystems. To this end, the APC is currently developing an optical benchtop experiment, called LISA On Table (LOT), which is representative of the three LISA spacecraft. A first module of the LOT experiment has been mounted and is being characterized. After completion this facility may be used by the LISA community to test hardware (photodiodes, phasemeters) or software (reconstruction algorithms) components.

Effects of wall friction on flow in a quasi-2D hopper

NASA Astrophysics Data System (ADS)

Shah, Neil; Birwa, Sumit; Carballo-Ramirez, Brenda; Pleau, Mollie; Easwar, Nalini; Tewari, Shubha

Our experiments on the gravity-driven flow of spherical particles in a vertical hopper examine how the flow rate varies with opening size and wall friction. We report here on a model simulation using LAMMPS of the experimental geometry, a quasi-2D hopper. Keeping inter-particle friction fixed, the coefficient of friction at the walls is varied from 0.0 to 0.9 for a range of opening sizes. Our simulations find a steady rate of flow at each wall friction and outlet size. The Janssen effect attributes the constant rate of flow of a granular column to the column height independence of the pressure at the base, since the weight of the grains is borne in part by friction at the walls. However, we observe a constant flow regime even in the absence of wall friction, suggesting that wall friction may not be a necessary condition for pressure saturation. The observed velocities of particles near the opening are used to extrapolate their starting positions had they been in free fall. In contrast to scaling predictions, our data suggest that the height of this free-fall arch does not vary with opening size for higher frictional coefficients. We analyze the velocity traces of particles to see the range over which contact interactions remain collisional as they approach the hopper outlet.

Seasonal and spatial variations of source and drinking water quality in small municipal systems of two Canadian regions.

PubMed

Scheili, A; Rodriguez, M J; Sadiq, R

2015-03-01

A one-year sampling program covering twenty-five small municipal systems was carried out in two Canadian regions to improve our understanding of the variability of water quality in small systems from water source to the end of the distribution system (DS). The database obtained was used to develop a global portrait of physical, chemical and microbiological water quality parameters. More precisely, the temporal and the spatial variability of these parameters were investigated. We observed that the levels of natural organic matter (NOM) were variable during different seasons, with maxima in the fall for both provinces. In the regions under study, the highest trihalomethane (THM) and haloacetic acid (HAA) levels were achieved in warmer seasons (summer, fall), as observed in previous studies involving large systems. Observed THM and HAA levels were three times higher in systems in the province of Newfoundland & Labrador than in the province of Quebec. Taste and odor indicators were detected during the summer and fall, and higher heterotrophic plate count (HPC) levels were associated with lower free chlorine levels. To determine spatial variations, stepwise statistical analysis was used to identify parameters and locations in the DS that act as indicators of drinking water quality. As observed for medium and large systems, free chlorine consumption, THM and HAA levels were dependent on their location in the DS. We also observed that the degradation of HAAs is more important in small systems than in medium or large DS reported in the literature, and this degradation can occur from the beginning of the DS. The results of this research may contribute to providing precious information on drinking water quality to small system operators and pave the way for several opportunities to improve water quality management. Copyright © 2014 Elsevier B.V. All rights reserved.

Temporal distribution and potential sources of atmospheric mercury measured at a high-elevation background station in Taiwan

NASA Astrophysics Data System (ADS)

Sheu, Guey-Rong; Lin, Neng-Huei; Wang, Jia-Lin; Lee, Chung-Te; Ou Yang, Chang-Feng; Wang, Sheng-Hsiang

2010-07-01

Measurements of gaseous elemental mercury (GEM), reactive gaseous mercury (RGM), and particulate mercury (PHg) have been conducted at Lulin Atmospheric Background Station (LABS) in Taiwan since April 2006. This was the first long-term free tropospheric atmospheric Hg monitoring program in the downwind region of East Asia, which is a major Hg emission source region. Between April 13, 2006 and December 31, 2007, the mean concentrations of GEM, RGM, and PHg were 1.73 ng m -3, 12.1 pg m -3, and 2.3 pg m -3, respectively. A diurnal pattern was observed for GEM with afternoon peaks and nighttime lows, whereas the diurnal pattern of RGM was opposite to that of GEM. Spikes of RGM were frequently observed between midnight and early morning with concurrent decreases in GEM and relative humidity and increases in O 3, suggesting the oxidation of GEM and formation of RGM in free troposphere (FT). Upslope movement of boundary layer (BL) air in daytime and subsidence of FT air at night resulted in these diurnal patterns. Considering only the nighttime data, which were more representative of FT air, the composite monthly mean GEM concentrations ranged between 1.06 and 2.06 ng m -3. Seasonal variation in nighttime GEM was evident, with lower concentrations usually occurring in summer when clean marine air masses prevailed. Between fall and spring, air masses passed the East Asian continent prior to reaching LABS, contributing to the elevated GEM concentrations. Analysis of GEM/CO correlation tends to support the argument. Good GEM/CO correlations were observed in fall, winter, and spring, suggesting influence of anthropogenic emission sources. Our results demonstrate the significance of East Asian Hg emissions, including both anthropogenic and biomass burning emissions, and their long-range transport in the FT. Because of the pronounced seasonal monsoon activity and the seasonal variation in regional wind field, export of the Asian Hg emissions to Taiwan occurs mainly during fall, winter, and spring.

A randomised controlled trial of low-dose aspirin for the prevention of fractures in healthy older people: protocol for the ASPREE-Fracture substudy.

PubMed

Barker, Anna L; McNeil, John J; Seeman, Ego; Ward, Stephanie A; Sanders, Kerrie M; Khosla, Sundeep; Cumming, Robert G; Pasco, Julie A; Bohensky, Megan A; Ebeling, Peter R; Woods, Robyn L; Lockery, Jessica E; Wolfe, Rory; Talevski, Jason

2016-08-01

Disability, mortality and healthcare burden from fractures in older people is a growing problem worldwide. Observational studies suggest that aspirin may reduce fracture risk. While these studies provide room for optimism, randomised controlled trials are needed. This paper describes the rationale and design of the ASPirin in Reducing Events in the Elderly (ASPREE)-Fracture substudy, which aims to determine whether daily low-dose aspirin decreases fracture risk in healthy older people. ASPREE is a double-blind, randomised, placebo-controlled primary prevention trial designed to assess whether daily active treatment using low-dose aspirin extends the duration of disability-free and dementia-free life in 19 000 healthy older people recruited from Australian and US community settings. This substudy extends the ASPREE trial data collection to determine the effect of daily low-dose aspirin on fracture and fall-related hospital presentation risk in the 16 500 ASPREE participants aged ≥70 years recruited in Australia. The intervention is a once daily dose of enteric-coated aspirin (100 mg) versus a matching placebo, randomised on a 1:1 basis. The primary outcome for this substudy is the occurrence of any fracture-vertebral, hip and non-vert-non-hip-occurring post randomisation. Fall-related hospital presentations are a secondary outcome. This substudy will determine whether a widely available, simple and inexpensive health intervention-aspirin-reduces the risk of fractures in older Australians. If it is demonstrated to safely reduce the risk of fractures and serious falls, it is possible that aspirin might provide a means of fracture prevention. The protocol for this substudy is registered with the Australian New Zealand Clinical Trials Registry (ACTRN12615000347561). Published by the BMJ Publishing Group Limited. For permission to use (where not already granted under a licence) please go to http://www.bmj.com/company/products-services/rights-and-licensing/

Tests of the Equivalence Principle via differential accelerometry on-ground, in a balloon and in space

NASA Astrophysics Data System (ADS)

Iafolla, Valerio; Peron, Roberto; Lorenzini, Enrico C.; Lucchesi, David; Santoli, Francesco; Lefevre, Carlo; Fiorenza, Emiliano; Lucente, Marco; Magnafico, Carmelo

Einstein’s theory of general relativity -- currently the best known description of gravitational phenomena -- relies on the validity of the so-called Einstein Equivalence Principle, which in turn is based on the Weak Equivalence Principle (WEP). The WEP states that the ratio of the gravitational mass to the inertial one is the same for all bodies, hence all fall with the same acceleration independently of their mass and composition. This is the Universality of Free Fall (UFF), a property which makes gravitation a universal phenomenon. The experimental tests which investigate the validity of UFF are among the most significant to verify Einstein's theory and among the most promising for the discovery of new physics beyond general relativity. The best tests have reached an accuracy of parts in (10^{13}), using rotating torsion balances (in the field of Earth and Sun) and Lunar Laser Ranging measurements (in the field of the Sun). We present here a concept for a new experimental test of WEP carried out in the gravity field of the Sun. Two test masses of different materials are the central elements of a differential accelerometer with zero baseline. A possible WEP violation would show up with a non-zero differential acceleration signal for the two elements falling in the given gravitational field. This basic concept of the measurement lends itself to three stages of development, with increasing projected accuracy levels. In the first stage, which is foreseen to be performed on ground, the differential accelerometer is placed on a pendulum, in such a way as to make the common center of mass coincident with the center of mass of the pendulum. Ensuring a very precise centering, such a system should provide a high degree of attenuation of the local seismic noise, which, together with an integration time of the order of tens of days, would allow verification of the WEP with an accuracy improved by at least an order of magnitude with respect to the state of the art. One of the strengths of this experiment is the know-how acquired from a previous study and technology development (GREAT: General Relativity Accuracy Test) that involved a test of the WEP in the gravity field of the Earth, in free fall inside a co-moving capsule released from a stratospheric balloon. This is the second stage, with a projected accuracy of a few parts in (10^{15}). The capsule would be carried at high altitude and released. During the fall, inside the capsule the detector would be in turn released, freely falling in vacuum; it would be initially spun about a horizontal axis in order to modulate a possible violating signal at the spin frequency (therefore enabling to distinguish the violation from other perturbations). The high accuracy of the experiment requires resolving a very small signal out of components like the instrument intrinsic noise and the noise components associated with its motion and gravity gradients. The detector would operate in cryogenic conditions and would be capable of rejecting linear and angular noise while retaining the signal of a possible violation. The third stage would imply accommodating the differential accelerometer, core of the measurement, in a very-low-noise environment as that offered by a space platform. This platform should have to employ a drag-free technology. A sensible advantage of space is the possibility of very long integration times, thereby lowering the random components of noise acting on the detector. The differential accelerometer concept will be discussed, along with design and prototyping performed along the years. Then an outline of the three subsequent stages of the experiment will be given.

Women in Free Clinics: An Assessment of Health-Related Quality of Life for Prevention and Health Education.

PubMed

Kamimura, Akiko; Myers, Kyl; Ashby, Jeanie; Trinh, Ha Ngoc; Nourian, Maziar M; Reel, Justine J

2015-08-01

Understanding gender influences on health-related quality of life (HRQoL) is important to improve women's health when considering diseases that afflict women specifically. The target population of this study was uninsured female free clinic patients who are low socio-economic status and lack access to healthcare resources. Free clinics provide free or reduced fee healthcare to individuals who lack access to primary care and are socio-economically disadvantaged. While approximately half of free clinic patients are women, there is a paucity of comprehensive health-related data for female free clinic patients. US born English, non-US born English, and Spanish speaking female free clinic patients completed a self-administered survey using a standardized women's HRQoL measure in Fall 2014 (N = 389). Female free clinic patients reported lower HRQoL on all aspects of women's health compared to the US baseline scores, and were less likely to utilize preventive care including: mammograms, Pap smear, and HPV vaccination compared to the US general population. Spanish speakers reported a higher percentage of having had mammography and Pap smear, and heard about HPV compared to the other two groups. US born English speakers reported lower levels of HRQoL in vasomotor symptoms and sleep symptoms, and the lowest percentage of breast health and Pap smear screenings compared to non-US born English and Spanish speakers. Non-US born English speakers reported higher preference for female physician compared to US born English speakers and Spanish speakers. Free clinic female patients need preventative interventions and educational opportunities to improve their overall HRQoL.

On a Free Boundary Problem for the Curvature Flow with Driving Force

NASA Astrophysics Data System (ADS)

Guo, Jong-Shenq; Matano, Hiroshi; Shimojo, Masahiko; Wu, Chang-Hong

2016-03-01

We study a free boundary problem associated with the curvature dependent motion of planar curves in the upper half plane whose two endpoints slide along the horizontal axis with prescribed fixed contact angles. Our first main result concerns the classification of solutions; every solution falls into one of the three categories, namely, area expanding, area bounded and area shrinking types. We then study in detail the asymptotic behavior of solutions in each category. Among other things we show that solutions are asymptotically self-similar both in the area expanding and the area shrinking cases, while solutions converge to either a stationary solution or a traveling wave in the area bounded case. We also prove results on the concavity properties of solutions. One of the main tools of this paper is the intersection number principle, however in order to deal with solutions with free boundaries, we introduce what we call "the extended intersection number principle", which turns out to be exceedingly useful in handling curves with moving endpoints.

Bromine incorporation factors for trihalomethane formation for the Mississippi, Missouri, and Ohio Rivers

USGS Publications Warehouse

Rathbun, R.E.

1996-01-01

The bromine incorporation factor describes the distribution of the four trihalomethane compounds in the mixture formed when a natural water is chlorinated. This factor was determined for the Mississippi, Missouri, and Ohio Rivers by chlorinating water samples at three levels each of pH and free chlorine concentration. Samples were collected during the summer, fall, and spring seasons of the year at 12 sites on the Mississippi River from Minneapolis, MN, to New Orleans, LA, and on the Missouri and Ohio Rivers 1.6 kilometers upstream from their confluences with the Mississippi. The bromine incorporation factor increased as the bromide concentration increased, and decreased as the pH, initial free-chlorine and dissolved organic-carbon concentrations increased. Variation of the bromine incorporation factor with distance along the Mississippi River approximately paralleled the variation of the bromide concentration with distance along the river, with the Missouri River samples having the highest bromine incorporation factors for all combinations of pH and free-chlorine concentration.

An atom interferometer inside a hollow-core photonic crystal fiber

PubMed Central

Xin, Mingjie; Leong, Wui Seng; Chen, Zilong; Lan, Shau-Yu

2018-01-01

Coherent interactions between electromagnetic and matter waves lie at the heart of quantum science and technology. However, the diffraction nature of light has limited the scalability of many atom-light–based quantum systems. We use the optical fields in a hollow-core photonic crystal fiber to spatially split, reflect, and recombine a coherent superposition state of free-falling 85Rb atoms to realize an inertia-sensitive atom interferometer. The interferometer operates over a diffraction-free distance, and the contrasts and phase shifts at different distances agree within one standard error. The integration of phase coherent photonic and quantum systems here shows great promise to advance the capability of atom interferometers in the field of precision measurement and quantum sensing with miniature design of apparatus and high efficiency of laser power consumption. PMID:29372180

Laser-Free Cold-Atom Gymnastics

NASA Astrophysics Data System (ADS)

Gould, Harvey; Feinberg, Benedict; Munger, Charles T., Jr.; Nishimura, Hiroshi

2017-01-01

We have performed beam transport simulations on ultra cold (2 μK) and cold (130 μK) neutral Cs atoms in the F = M = + 4 (magnetic weak-field seeking) ground state. We use inhomogeneous magnetic fields to focus and accelerate the atoms. Acceleration of neutral atoms by an inhomogeneous magnetic field was demonstrated by Stern and Gerlach in 1922. In the simulations, a two mm diameter cloud of atoms is released to fall under gravity. A magnetic coil focuses the falling atoms. After falling 41 cm, the atoms are reflected in the magnetic fringe field of a solenoid. They return to their starting height, about 0.7 s later, having passed a second time through the focusing coil. The simulations show that > 98 % of ultra cold Cs atoms and > 70 % of cold Cs atoms will survive at least 15 round trips (assuming perfect vacuum). More than 100 simulations were run to optimize coil currents and focusing coil diameter and height. Simulations also show that atoms can be launched into a fountain. An experimental apparatus to test the simulations, is being constructed. This technique may find application in atomic fountain clocks, interferometers, and gravitometers, and may be adaptable for use in microgravity. It may also work with Bose-Einstein condensates of paramagnetic atoms.

DOE Office of Scientific and Technical Information (OSTI.GOV)

Oliver, R.; Soler, R.; Terradas, J.

Coronal rain clumps and prominence knots are dense condensations with chromospheric to transition region temperatures that fall down in the much hotter corona. Their typical speeds are in the range 30–150 km s{sup −1} and of the order of 10–30 km s{sup −1}, respectively, i.e., they are considerably smaller than free-fall velocities. These cold blobs contain a mixture of ionized and neutral material that must be dynamically coupled in order to fall together, as observed. We investigate this coupling by means of hydrodynamic simulations in which the coupling arises from the friction between ions and neutrals. The numerical simulations presentedmore » here are an extension of those of Oliver et al. to the partially ionized case. We find that, although the relative drift speed between the two species is smaller than 1 m s{sup −1} at the blob center, it is sufficient to produce the forces required to strongly couple charged particles and neutrals. The ionization degree has no discernible effect on the main results of our previous work for a fully ionized plasma: the condensation has an initial acceleration phase followed by a period with roughly constant velocity, and, in addition, the maximum descending speed is clearly correlated with the ratio of initial blob to environment density.« less

The variation in frequency locations in Doppler ultrasound spectra for maximum blood flow velocities in narrowed vessels.

PubMed

Zhang, Yingyun; Zhang, Yufeng; Gao, Lian; Deng, Li; Hu, Xiao; Zhang, Kexin; Li, Haiyan

2017-11-01

This study assessed the variation in the frequency locations in the Doppler ultrasound spectra for the maximum blood flow velocities of in vessels with different degrees of bilaterally axisymmetric stenosis. This was done by comparing the relationship between the velocity distributions and corresponding Doppler power spectra. First, a geometric vessel model with axisymmetric stenosis was established. This made it possible to obtain the blood flow velocity distributions for different degrees of stenosis from the solutions of the Navier-Stokes equations. Then, the Doppler spectra were calculated for the entire segment of the vessel that was covered by the sound field. Finally, the maximum frequency locations for the spectra were determined based on the intersections of the maximum values chosen from the calculated blood flow velocity distributions and their corresponding spectra. The computational analysis showed that the maximum frequencies, which corresponded to the maximum blood flow velocities for different degrees of stenosis, were located at different positions along the spectral falling edges. The location for a normal (stenosis free) vessel was in the middle of the falling edge. For vessels with increasing degrees of stenosis, this location shifted approximately linearly downward along the falling edge. For 40% stenosis, the location reached a position at the falling edge of 0.32. Results obtained using the Field II simulation tool demonstrated the validity of the theoretical analysis and calculations, and may help to improve the maximum velocity estimation accuracy for Doppler blood flow spectra in stenosed vessels. Copyright © 2017 IPEM. Published by Elsevier Ltd. All rights reserved.

Vibrotactile neurofeedback balance training in patients with Parkinson's disease: reducing the number of falls.

PubMed

Rossi-Izquierdo, Marcos; Ernst, Arne; Soto-Varela, Andrés; Santos-Pérez, Sofía; Faraldo-García, Ana; Sesar-Ignacio, Angel; Basta, Dietmar

2013-02-01

The aim of this study was to assess effectiveness of balance training with a vibrotactile neurofeedback system in improving overall stability in patients with Parkinson's disease (PD). Ten patients diagnosed with idiopathic PD were included. Individualization of the rehabilitation program started with a body sway analysis of stance and gait tasks (Standard Balance Deficit Test, SBDT) by using the diagnostic tool of the applied device (Vertiguard(®)-RT). Those tasks with the poorest outcome as related to age- and gender-related controls were included in the training program (not more than six tasks). Improvement of postural stability was assessed by performing SBDT, Sensory Organization Test (SOT) of Computerized Dynamic Posturography (CDP), Dizziness Handicap Inventory (DHI), activity-specific balance confidence scale and recording the number of falls over the past three months. Furthermore, scores of SOT and DHI of 10 PD patients previously trained in an earlier study (by using CDP) were compared with results of those in the present study. After neurofeedback training (NFT), there was a statistically significant improvement in body sway (calculated over all training tasks), number of falls, and scores of SOT, DHI and ABC. In comparison with CDP-training, a statistically significant higher increase of SOT score was observed for patients after NFT with the Vertiguard-RT device compared to CDP training. Our results showed that a free-field vibrotactile NFT with Vertiguard(®)-RT device can improve balance in PD patients in everyday life conditions very effectively, which might led in turn to a reduction of falls. Copyright © 2012 Elsevier B.V. All rights reserved.

Can Fire and Rescue Services and the National Health Service work together to improve the safety and wellbeing of vulnerable older people? Design of a proof of concept study.

PubMed

Lowton, Karen; Laybourne, Anne H; Whiting, David G; Martin, Finbarr C

2010-12-03

Older adults are at increased risk both of falling and of experiencing accidental domestic fire. In addition to advanced age, these adverse events share the risk factors of balance or mobility problems, cognitive impairment and socioeconomic deprivation. For both events, the consequences include significant injury and death, and considerable socioeconomic costs for the individual and informal carers, as well as for emergency services, health and social care agencies.Secondary prevention services for older people who have fallen or who are identifiable as being at high risk of falling include NHS Falls clinics, where a multidisciplinary team offers an individualised multifactorial targeted intervention including strength and balance exercise programmes, medication changes and home hazard modification. A similar preventative approach is employed by most Fire and Rescue Services who conduct Home Fire Safety Visits to assess and, if necessary, remedy domestic fire risk, fit free smoke alarms with instruction for use and maintenance, and plan an escape route. We propose that the similarity of population at risk, location, specific risk factors and the commonality of preventative approaches employed could offer net gains in terms of feasibility, effectiveness and acceptability if activities within these two preventative approaches were to be combined. This prospective proof of concept study, currently being conducted in two London boroughs, (Southwark and Lambeth) aims to reduce the incidence of both fires and falls in community-dwelling older adults. It comprises two concurrent 12-month interventions: the integration of 1) fall risk assessments into the Brigade's Home Fire Safety Visit and 2) fire risk assessments into Falls services by inviting older clinic attendees to book a Visit. Our primary objective is to examine the feasibility and effectiveness of these interventions. Furthermore, we are evaluating their acceptability and value to key stakeholders and services users. If our approach proves feasible and the risk assessment is both effective and acceptable, we envisage advocating a partnership model of working more broadly to fire and rescue services and health services in Britain, such that effective integration of preventative services for older people becomes routine for an ageing population.