Gyro spring augmentation system

Spring-loaded piston with provision for hydraulic control of spring action varies the stiffness of hydraulic control systems

High Resolution Imaging Systems For Spin-Stabilized Probe Spacecraft

A novel design for a high-resolution imaging system which includes on-board data editing and optical navigation, suggests high quality images can be acquired from spin-stabilized spacecraft oriented towards high velocity, short duration planetary missions ("Probes"). The approach to designing imaging systems requires that mission objectives be met within the physical and fiscal constraints imposed by the spacecraft and mission design. Severe constraints imposed on a Comet Halley probe (for example, 57km/sec encounter velocity with a small, 10km diameter, object coupled with a great uncertainty in encounter time and distance, were overcome by innovative use of existing technology. Such designs suggest that 3-axis stabilization or non-spinning platforms are not necessary to acquire high resolution, high quality planetary images

Hudson Bay Ice Conditions

Monthly mean ice cover distributions for Hudson Bay have been derived, based upon an analysis of nine years of aerial reconnaissance and other data. Information is presented in map form, along with discussion of significant features. Ice break-up is seen to work southward from the western, northern, and eastern edges of the Bay; the pattern seems to be a result of local topography, currents and persistent winds. Final melting occurs in August. Freeze-up commences in October, along the northwestern shore, and proceeds southeastward. The entire Bay is ice-covered by early January, except for persistent shore leads.Conditions de la glace dans la mer d’Hudson.  A partir de l’analyse de neuf années de reconnaissances aériennes et d’autres données, on a pu déduire des moyennes mensuelles de distribution de la glace pour la mer d’Hudson.  L’information est présentée sous formes de cartes et de discussion des éléments significatifs.  On y voit que la débâcle progresse vers le sud à partir des marges ouest, nord et est de la mer; cette séquence semble être le résultat de la topographie locale, des courants et des vents dominants.  La fonte se termine en août.  L’engel commence en octobre le long de la rive nord-ouest et progresse vers le sud-est.  Sauf pour les chenaux côtiers persistants, la mer est entièrement gelée au début de janvier

Selling just preservation

Treves et al. argue for better representation of voiceless groups in current policy decisions. We agree with the argument but believe it will be challenging to convince enough people of its importance to change policy — especially those political groups who are not predisposed to agreeing with these kinds of arguments. We draw on the social psychology literature to recommend three principles for increasing the persuasiveness of the argument to the public: pre-suasion, framing, and tailoring for the audience. We apply these principles to make concrete recommendations for framing the argument to persuade the American political right

Isotopes from Fecal Material Provides Evidence of Recent Diet of Prairie Deer Mice

Prairie deer mice are important predators in many agricultural systems, and through their diet they can help to regulate pest insect and weed populations. Our objective was to test whether fecal material is an effective means of detailing the foraging ecology of small mammals. We conducted three studies to evaluate the efficacy of this technique: 1) field-collected fecal material from unknown deer mice from late winter to early spring, 2) fecal material collected in an enclosure with mice fed a mix of C3 and C4 plant seeds, and 3) fecal material from tagged female mice in the field. We detected significant shifts in δ13C in one study and δ15N in another relative to spring thaw (δ13C: –13.34 vs. –10.72, P = 0.01, δ15N: 4.92 vs. 4.09, P = 0.03), a significant correlation between the relative amounts of two seed types and δ13C (slope = 5.46, SE = 1.82, P \u3c 0.01), and a significant decrease in δ15N due to nursing (4.57 ± 0.19 vs 3.28 ± 0.47, P = 0.02). Use of this technique will help to clarify foraging of this economically important species in agroecosystems

Isotopes from Fecal Material Provides Evidence of Recent Diet of Prairie Deer Mice

Prairie deer mice are important predators in many agricultural systems, and through their diet they can help to regulate pest insect and weed populations. Our objective was to test whether fecal material is an effective means of detailing the foraging ecology of small mammals. We conducted three studies to evaluate the efficacy of this technique: 1) field-collected fecal material from unknown deer mice from late winter to early spring, 2) fecal material collected in an enclosure with mice fed a mix of C3 and C4 plant seeds, and 3) fecal material from tagged female mice in the field. We detected significant shifts in δ13C in one study and δ15N in another relative to spring thaw (δ13C: –13.34 vs. –10.72, P = 0.01, δ15N: 4.92 vs. 4.09, P = 0.03), a significant correlation between the relative amounts of two seed types and δ13C (slope = 5.46, SE = 1.82, P \u3c 0.01), and a significant decrease in δ15N due to nursing (4.57 ± 0.19 vs 3.28 ± 0.47, P = 0.02). Use of this technique will help to clarify foraging of this economically important species in agroecosystems

Thermal excitation of Trivelpiece-Gould modes in a pure electron plasma

Thermally excited plasma modes are observed in trapped, near-thermal-equilibrium pure electron plasmas over a temperature range of 0.05<T<5 eV. The measured thermal emission spectra together with a separate measurement of the wave absorption coefficient uniquely determines the temperature. Alternately, kinetic theory including the antenna geometry and the measured mode damping (i.e. spectral width) gives the plasma impedance, obviating the reflection measurement. This non-destructive temperature diagnostic agrees well with standard diagnostics, and may be useful for expensive species such as anti-matter

A Point Focusing Monochromator for the Study of Low-Angle X-Ray Diffraction: Determining the Size Distributions of Carbon Blacks and a Precision Determination of the Size of Dow Latex Particles

A point focusing x-ray monochromator was designed and constructed for low angle scattering studies. The anastigmatic point focus is achieved by means of two cylindrically bent quartz crystals whose focal circles are mutually perpendicular. The beam, emanating from the copper target of an x-ray tube, is reflected in succession, first from the crystal defining the horizontal focal circle and, second from the crystal defining the vertical focal circle following which it comes to a mono chromatic point focus of wavelength 1.537 A (Cu Ko(1). The sample to be studied is placed between the second crystal and the point focus, and the scattered beam is detected by means of a photographic plate placed at the point focus, at right angles to the undeviated beam, the latter being suppressed by means of an absorber. Mathematical analysis, in which a ray was traced through the two crystal system, revealed correctly the shape and size of the point focus, and the possibility of reducing the latter in size by stopping down the beam emerging from the target. The instrument and its lining up procedure is described in detail, particularly the latter since the orientation of the two crystals relative to each other and the x-ray tube involve twelve degrees of freedom. Suggestions for improving the intensity of the instrument are made . These consist of (1) substitution of topaz crystals for quartz, (2) use of helium atmosphere instead of air to surround the x-ray beam (3) reorientation of the x-ray tube to permit smaller angles of emergence of the beam. As a trial run for the instrument, the scattering patterns of two kinds of carbon black (good scatterers) were obtained from which the average particle sizes and size distributions were calculated