6,850 research outputs found

    Titanium honeycomb structure

    Get PDF
    A brazed titanium honeycomb sandwich system for supersonic transport wing cover panels provides the most efficient structure spanwise, chordwise, and loadwise. Flutter testing shows that high wing stiffness is most efficient in a sandwich structure. This structure also provides good thermal insulation if liquid fuel is carried in direct contact with the wing structure in integral fuel tanks

    Very high voltage latching relay

    Get PDF
    Relay consists of high voltage reed switch actuated by rotating permanent magnet mounted on stepper motor shaft, with actuation assembly isolated from high voltage circuit. Unit can be modified for use as double pole or double pole double throw latching relay and can be used in either air or vacuum

    Process for preparing liquid metal electrical contact device

    Get PDF
    The parts of an electrical contact device are treated by sputter etching to remove the parent metal oxide. Prior to exposure of the electrodes to any oxygen, a sacrificial metal is sputter deposited on the parts. Preferably this sacrificial metal is one that oxidizes slowly and is readily dissolved by the liquid metal. The sacrificial metal may then be removed from unwanted areas. The remainder of the ring and the probe to be wet by the liquid metal are submerged in the liquid metal or the liquid metal is flushed over these areas, preferably while they are being slightly abraded, unitl all the sacrificial material on these portions is wet by the liquid metal. In doing so the liquid metal dissolves the sacrificial metal and permanently wets the parent metal. Preferred materials used in the process and for the electrodes of electrical contact devices are high purity (99.0%) nickel or AISI type 304 stainless steel for the electrical contact devices, gallium as the liquid metal, and gold as the sacrificial material

    Liquid Level Sensor for High Temperature Molten Salt in Confined Container

    Get PDF
    Electrical resistance measurements on different rod materials in liquid solutions, molten salts, or molten lead are considered to design a liquid level sensor in a sealed containers when the temperature of the fluid is very high (~1000ºC) and conventional measurements are not possible due to properties of the fluid or condition of the container. An analytical solution to the problem is adopted to reduce the cost of the sensor and overcome the difficulties of calibration of sensors at high temperature for prediction of the level of liquid. An electrical circuit model is suggested for analytical solution to compute the resistivity versus height of the electrode rod submerged in the liquid in a narrow container. Good prediction of circuit model for experimental results is verified by comparison of analytical results of different combination of liquid solutions and rods’ material with experimental graphs

    Sex and the Stars: The Enduring Structure of Gender Discrimination in the Space Industry

    Get PDF
    Women have much to contribute to the worlds of science and technology, and the world is poorer for women’s historical exclusion from such scientific endeavors. Although many industries exhibit gender discrepancies and continue to be shaped by sexism (e.g., banking, farming, mining, trucking, engineering, etc.), no other industry features so predominantly in our future-oriented visions for humanity as does science, and particularly space science. For women working in the male-dominated global space industry, space is a female frontier with a celestial ceiling. The United Nations (UN) reports that, in 2016, only 20% of workers in the space industry were women, and these figures had not improved in three decades. Women cannot defy the gravity of their situation without institutional change and a dramatic shift in cultural attitudes around gender. Science and human rights are linked; participation in science can improve a woman’s education and independence, life opportunities, status in society, and basic human rights. On Earth, patriarchal ideologies punctuate daily life, but space presents a chance for humanity to start a new chapter

    The Role of Human Nature in Philosophy of Education

    Get PDF

    Form Criticism

    Get PDF

    Egg-laying substrate selection for optimal camouflage by quail

    Get PDF
    Camouflage is conferred by background matching and disruption, which are both affected by microhabitat [1]. However, microhabitat selection that enhances camouflage has only been demonstrated in species with discrete phenotypic morphs [2 and 3]. For most animals, phenotypic variation is continuous [4 and 5]; here we explore whether such individuals can select microhabitats to best exploit camouflage. We use substrate selection in a ground-nesting bird (Japanese quail, Coturnix japonica). For such species, threat from visual predators is high [6] and egg appearance shows strong between-female variation [7]. In quail, variation in appearance is particularly obvious in the amount of dark maculation on the light-colored shell [8]. When given a choice, birds consistently selected laying substrates that made visual detection of their egg outline most challenging. However, the strategy for maximizing camouflage varied with the degree of egg maculation. Females laying heavily maculated eggs selected the substrate that more closely matched egg maculation color properties, leading to camouflage through disruptive coloration. For lightly maculated eggs, females chose a substrate that best matched their egg background coloration, suggesting background matching. Our results show that quail “know” their individual egg patterning and seek out a nest position that provides most effective camouflage for their individual phenotyp
    • …
    corecore