The motor fitness of primary school boys and girls

The purpose of this study was to assess the motor fitness level of boys and girls in the lower elementary grades and to differentiate the motor fitness level of boys and girls placed in a pre-first class with boys and girls placed in a regular first grade. [This is an excerpt from the abstract. For the complete abstract, please see the document.

The Resuspension of Flocculent Solids in Sedimentation Basins

The phenomenon of resuspension has been considered to be an important factor in the imperfect behavior of sedimentation basins receiving suspensions containing flocculent solids. Resuspension is the entrainment into the flow of particles that have once settled to the floor of the basin. This investigation has been undertaken to study the resuspension phenomenon and to find ways in which its harmful effects can be reduced. Resuspension has been found extremely difficult to isolate and define scientifically because many other factors produce the same overall effect upon the settling tank. Furthermore it is practically necessary to identify individual particles in order to know whether a particular one found in suspension in the downstream portion of a settling tank had earlier been settled out and resting on the floor. Laboratory studies on settling tank behavior were conducted on a glass-walled "scour flume" 1.27 ft wide by 14 ft long with depth adjustable from 0.5 to 2.0 ft (see Fig. 1.1). In order to simulate certain aspects of the behavior of full-scale settling tanks the laboratory flume was fitted with moving flight scrapers similar to those installed in primary sewage settling tanks. For some of the later tests the flume was fitted with 14 probes that made it possible to sample the tank contents at practically any point of five cross sections along the length of the flume. Most of the studies on the laboratory flume utilized a discrete suspension of gilsonite {s. g. 1.04) particles or a flocculent suspension of ferric chloride and bentonite clay particles. Tests for critical velocity required for entrainment of particles from a smooth bed showed that fine light particles are more easily lifted from the bed than was previously supposed. With scrapers moving upstream, the critical velocity for two sizes of gilsonite tested was found to vary between 10.5 and 14.5 times the particle settling velocity. Field and laboratory studies on one scheme proposed to improve the performance of settling tanks - a series of transverse sloping baffles installed throughout the main body of a rectangular settling tank - both indicate that baffling a tank is not the answer. Tests on full-scale settling tanks of a sewage treatment plant showed that conventional measures of settling tank performance are meaningless when the suspension entering the tank is flocculent (as is sewage). Newer measures of performance are proposed, which show promise in evaluating the behavior of settling tanks receiving flocculent suspensions

Experimentally Observed Instability of a Laminar Ekman Flow in a Rotating Basin

In studying the axi-symmetric flow induced by source-sink distributions in a rotating cylindrical basin in the absence of radial barriers, a highly organized pattern of instability has been observed in the laminar Ekman layer along the bottom of the basin. The instability manifests itself in the form of almost perfectly concentric cylindrical sheets or curtains of water which rise as sharply defined vertical jets from the Ekman layer and penetrate the entire depth of fluid. A less sharply defined downward motion between the curtains completes the circulation celis thus developed. At some maximum critical radius, the curtains usually disappear, and the flow at larger radii is a stable, laminar Ekman flow. Quantitative observations of ring spacing and critical radius are reported for experiments in which angular velocity, flow rate, viscosity and total depth of water were varied over experimentally available ranges

The Mars observer camera

A camera designed to operate under the extreme constraints of the Mars Observer Mission was selected by NASA in April, 1986. Contingent upon final confirmation in mid-November, the Mars Observer Camera (MOC) will begin acquiring images of the surface and atmosphere of Mars in September-October 1991. The MOC incorporates both a wide angle system for low resolution global monitoring and intermediate resolution regional targeting, and a narrow angle system for high resolution selective surveys. Camera electronics provide control of image clocking and on-board, internal editing and buffering to match whatever spacecraft data system capabilities are allocated to the experiment. The objectives of the MOC experiment follow

Sam Black gets a shot at Br\u27er Rabbit .

Color Black Americana stereographs. Set of 3. Features a black boy hunting with his dad. Entitled Sam Black gets a shot \u27Br\u27er Rabbit\u27, Lordy, Dad! Be Yous Kilt. and Oh! Golly, But Dat Ol\u27 Gun Done Kick .https://stars.library.ucf.edu/carolmundy-text/1008/thumbnail.jp

Exploring Planets with Directed Aerial Robot Explorers

Global Aerospace Corporation (GAC) is developing a revolutionary system architecture for exploration of planetary atmospheres and surfaces from atmospheric altitudes. The work is supported by the NASA Institute for Advanced Concepts (NIAC). The innovative system architecture relies upon the use of Directed Aerial Robot Explorers (DAREs), which essentially are long-duration-flight autonomous balloons with trajectory control capabilities that can deploy swarms of miniature probes over multiple target areas. Balloon guidance capabilities will offer unprecedented opportunities in high-resolution, targeted observations of both atmospheric and surface phenomena. Multifunctional microprobes will be deployed from the balloons once over the target areas, and perform a multitude of functions, such as atmospheric profiling or surface exploration, relaying data back to the balloons or an orbiter. This architecture will enable low-cost, low-energy, long-term global exploration of planetary atmospheres and surfaces. This paper focuses on a conceptual analysis of the DARE architecture capabilities and science applications for Venus, Titan and Jupiter. Preliminary simulations with simplified atmospheric models show that a relatively small trajectory control wing can enable global coverage of the atmospheres of Venus and Titan by a single balloon over a 100-day mission. This presents unique opportunities for global in situ sampling of the atmospheric composition and dynamics, atmospheric profiling over multiple sites with small dropsondes and targeted deployment of surface microprobes. At Jupiter, path guidance capabilities of the DARE platforms permits targeting localized regions of interest, such as "hot spots" or the Great Red Spot. A single DARE platform at Jupiter can sample major types of the atmospheric flows (zones and belts) over a 100-day mission. Observations by deployable probes would reveal if the differences exist in radiative, dynamic and compositional environments at these sites

Selected test results from the LiFeBatt iron phosphate Li-ion battery.

In this paper the performance of the LiFeBatt Li-ion cell was measured using a number of tests including capacity measurements, capacity as a function of temperature, ohmic resistance, spectral impedance, high power partial state of charge (PSOC) pulsed cycling, pulse power measurements, and an over-charge/voltage abuse test. The goal of this work was to evaluate the performance of the iron phosphate Li-ion battery technology for utility applications requiring frequent charges and discharges, such as voltage support, frequency regulation, and wind farm energy smoothing. Test results have indicated that the LiFeBatt battery technology can function up to a 10C{sub 1} discharge rate with minimal energy loss compared to the 1 h discharge rate (1C). The utility PSOC cycle test at up to the 4C{sub 1} pulse rate completed 8,394 PSOC pulsed cycles with a gradual loss in capacity of 10 to 15% depending on how the capacity loss is calculated. The majority of the capacity loss occurred during the initial 2,000 cycles, so it is projected that the LiFeBatt should PSOC cycle well beyond 8,394 cycles with less than 20% capacity loss. The DC ohmic resistance and AC spectral impedance measurements also indicate that there were only very small changes after cycling. Finally, at a 1C charge rate, the over charge/voltage abuse test resulted in the cell venting electrolyte at 110 C after 30 minutes and then open-circuiting at 120 C with no sparks, fire, or voltage across the cell

One-pot silyl ketene acetal-formation-Mukaiyama–Mannich additions to imines mediated by trimethylsilyl trifluoromethanesulfonate

In the presence of trimethylsilyl trifluoromethanesulfonate and trialkylamine base, thioesters are readily converted to silyl ketene acetals in situ and undergo Mukaiyama–Mannich addition to N-phenylimines in one pot. The silyl triflates appears to play two roles, activating both the thioester and the imine. This process also works well when thioesters are replaced with amides, esters, or ketones. Products are isolated as desilylated anilines without the necessity of a deprotection step. Yields range from 65-99%

Reactor Technology Options Study for Near-Term Deployment of GNEP Grid-Appropriate Reactors

World energy demand is projected to significantly increase over the coming decades. The International Energy Agency projects that electricity demand will increase 50% by 2015 and double by 2030, with most of the increase coming in developing countries as they experience double-digit rates of economic growth and seek to improve their standards of living. Energy is the necessary driver for human development, and the demand for energy in these countries will be met using whatever production technologies are available. Recognizing this inevitable energy demand and its implications for the United States, the U.S. National Security Strategy has proposed the Global Nuclear Energy Partnership (GNEP) to work with other nations to develop and deploy advanced nuclear recycling and reactor technologies. This initiative will help provide reliable, emission-free energy with less of the waste burden of older technologies and without making available separated plutonium that could be used by rogue states or terrorists for nuclear weapons. These new technologies will make possible a dramatic expansion of safe, clean nuclear energy to help meet the growing global energy demand. In other words, GNEP seeks to create an international regime to support large-scale growth in the worldwide use of nuclear energy without increasing the risk of nuclear weapon proliferation. This global expansion of nuclear power is strategically important to the United States for several reasons, including the following: (1) National security, by reducing the competition and potential for conflict over increasingly scarce fossil energy resources; (2) Economic security, by helping maintain stable prices for nonrenewable resources such as oil, gas, and coal; (3) Environmental security, by replacing or off-setting large-scale burning of greenhouse gas-emitting fuels for electricity production; and (4) Regaining technical leadership, through deployment of innovative U.S. technology-based reactors. Fully meeting the GNEP vision may require the deployment of thousands of reactors during the next century in dozens of countries, many of which are in the developing world where nuclear energy is not used currently. Such a large-scale deployment will have significant implications related to both fuel supply and spent fuel/waste management, both domestically and worldwide. Consequently, GNEP must address the development and demonstration of proliferation-resistant technologies to ensure both a safe and sustainable nuclear fuel cycle, and reactor designs that are appropriate for the range of needs across the global community. The focus of this report is the latter need, that is, the development and demonstration of proliferation-resistant reactors that are well matched to the needs and capabilities of developing countries

Evolution of "51Peg b-like" Planets

About one-quarter of the extrasolar giant planets discovered so far have orbital distances smaller than 0.1 AU. These ``51Peg b-like'' planets can now be directly characterized, as shown by the planet transiting in front the star HD209458. We review the processes that affect their evolution. We apply our work to the case of HD209458b, whose radius has been recently measured. We argue that its radius can be reproduced only when the deep atmosphere is assumed to be unrealistically hot. When using more realistic atmospheric temperatures, an energy source appears to be missing in order to explain HD209458b's large size. The most likely source of energy available is not in the planet's spin or orbit, but in the intense radiation received from the parent star. We show that the radius of HD209458b can be reproduced if a small fraction (~1%) of the stellar flux is transformed into kinetic energy in the planetary atmosphere and subsequently converted to thermal energy by dynamical processes at pressures of tens of bars.Comment: 11 pages including 9 figures. A&A, in press. Also available at http://www.obs-nice.fr/guillot/pegasi-planets