573 research outputs found

    Method of bonding metals with a radio-opaque adhesive/sealant for void detection and product made

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    A method and structure for providing radio-opaque polymer compounds for use in metal bonding and sealing. A powder filler comprising a high atomic number metal or compound thereof is incorporated into a polymer compound to render it more radio-opaque than the surrounding metal structures. Voids or other discontinuities in the radio-opaque polymer compound can then be detected by x-ray inspection or other non-destructive radiographic procedure

    Space Shuttle Body Flap Actuator Bearing Testing for NASA Return to Flight

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    The Space Shuttle body flap is located beneath the main engine nozzles and is required for proper aerodynamic control during orbital descent. Routine inspection of one of four body flap actuators found one of the actuator bearings had degraded and blackened balls. A test program was initiated to demonstrate that it is acceptable to operate bearings which are degraded from operation over several flights. This test exposed the bearing to predicted flight axial loads, speeds and temperatures. Testing at 140 F has been completed, and results indicate the previously flown bearings are acceptable for up to 12 additional missions. Additional testing is underway to determine the lubricant life at various temperatures and stresses and to further understand the mechanism that caused the blacken balls. Initial results of this testing indicates that bearing life is shorten at room temperature possibly due fact that higher temperature (140 F) accelerates the flow of grease and oil into the wear surfac

    Ball Bearings Equipped for In Situ Lubrication on Demand

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    In situ systems that provide fresh lubricants to ball/race contacts on demand have been developed to prolong the operational lives of ball bearings. These systems were originally intended to be incorporated into ball bearings in mechanisms that are required to operate in outer space for years, in conditions in which lubricants tend to deteriorate and/or evaporate. These systems may also be useful for similarly prolonging bearing lifetimes on Earth. Reservoirs have been among the means used previously to resupply lubricants. Lubricant- resupply reservoirs are bulky and add complexity to bearing assemblies. In addition, such a reservoir cannot be turned on or off as needed: it supplies lubricant continuously, often leading to an excess of lubricant in the bearing. A lubricator of the present type includes a porous ring cartridge attached to the inner or the outer ring of a ball bearing (see Figure 1). Oil is stored in the porous cartridge and is released by heating the cartridge: Because the thermal expansion of the oil exceeds that of the cartridge, heating causes the ejection of some oil. A metal film can be deposited on a face of the cartridge to serve as an electrical-resistance heater. The heater can be activated in response to a measured increase in torque that signals depletion of oil from the bearing/race contacts. Because the oil has low surface tension and readily wets the bearing-ring material, it spreads over the bearing ring and eventually reaches the ball/race contacts. The Marangoni effect (a surface-tension gradient associated with a temperature gradient) is utilized to enhance the desired transfer of lubricant to the ball/race contacts during heating. For a test, a ball bearing designed for use at low speed was assembled without lubricant and equipped with a porous-ring lubricator, the resistance heater of which consumed a power of less than 1 W when triggered on by a torque-measuring device. In the test, a load of 20 lb (.89 N) was applied and the bearing was turned at a rate of 200 RPM. The lubricator control was turned on at the beginning of the test, turned off for about 800 seconds, then turned on again. As shown in Figure 2, the controlled lubricator stabilized the torque in a low range, starting immediately after initial turn-on and immediately after resumption of the lubricator control

    In Situ, On-Demand Lubrication System Developed for Space Mechanisms

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    Many moving mechanical assemblies (MMA) for space mechanisms rely on liquid lubricants to provide reliable, long-term performance. The proper performance of the MMA is critical in assuring a successful mission. Historically, mission lifetimes were short and MMA duty cycles were minimal. As mission lifetimes were extended, other components, such as batteries and computers, failed before lubricated systems. However, improvements in these ancillary systems over the last decade have left the tribological systems of the MMAs as the limiting factor in determining spacecraft reliability. Typically, MMAs are initially lubricated with a very small charge that is supposed to last the entire mission lifetime, often well in excess of 5 years. In many cases, the premature failure of a lubricated component can result in mission failure

    Friendship vs. Colonialism: Investigating how E.M. Forster uses Empathy in A Passage to India

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    Upon its publication in 1924, E.M. Forster’s A Passage to India was recognized for its insightful and sympathetic portrayal of Anglo-Indian relations. More recently, the novel’s reception has been shaped by postcolonial readings, highlighting its engagement with colonialism, racial tensions, and cultural disparities. The friendship the novel centers around– and ultimately its failure, induced by a rape accusation– serves as a polarizing event for critical interpretations. Is the failure of sympathy in the novel significant in any anticolonial sense, as Zakia Pathak’s criticism argues? Or does it exist as an apolitical distraction as Nirad Chaudhuri implies? Investigating these critiques, this paper bases its argument on Forster’s beliefs about politics and friendship, as stated in his essay “What I Believe”. This paper will posit that the inability of the main characters to forge meaningful friendships across a colonial divide serves as a protest, in it of itself, against the machine of colonialism.https://orb.binghamton.edu/research_days_posters_2025/1144/thumbnail.jp

    The AzTEC mm-Wavelength Camera

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    AzTEC is a mm-wavelength bolometric camera utilizing 144 silicon nitride micromesh detectors. Herein we describe the AzTEC instrument architecture and its use as an astronomical instrument. We report on several performance metrics measured during a three month observing campaign at the James Clerk Maxwell Telescope, and conclude with our plans for AzTEC as a facility instrument on the Large Millimeter Telescope.Comment: 13 pages, 15 figures, accepted for publication in Monthly Notice

    Probabilistic Analysis of Space Shuttle Body Flap Actuator Ball Bearings

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    A probabilistic analysis, using the 2-parameter Weibull-Johnson method, was performed on experimental life test data from space shuttle actuator bearings. Experiments were performed on a test rig under simulated conditions to determine the life and failure mechanism of the grease lubricated bearings that support the input shaft of the space shuttle body flap actuators. The failure mechanism was wear that can cause loss of bearing preload. These tests established life and reliability data for both shuttle flight and ground operation. Test data were used to estimate the failure rate and reliability as a function of the number of shuttle missions flown. The Weibull analysis of the test data for the four actuators on one shuttle, each with a 2-bearing shaft assembly, established a reliability level of 96.9 percent for a life of 12 missions. A probabilistic system analysis for four shuttles, each of which has four actuators, predicts a single bearing failure in one actuator of one shuttle after 22 missions (a total of 88 missions for a 4-shuttle fleet). This prediction is comparable with actual shuttle flight history in which a single actuator bearing was found to have failed by wear at 20 missions

    The Box Problem

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    The box problem is taken from Calculus 1, where a student is asked to maximize the volume of a box constructed from a rectangular piece of cardboard with squares removed at the corners. We are interested in what the width and length need to be in order to have at least a rational answer for the optimum height. In 2000, Cuoco used Eisenstein triples to find the dimensions. Hotchkiss expanded on Cuoco\u27s work in 2002 and used an elliptical equation to find the dimensions needed for the box. This paper answers two open questions posed by Hotchkiss: proving that the smallest possible distinct dimensions that produce an integral solution are 5 and 8. Also the minimum distnct dimensions are examined in general

    Experimental thermal mechanics of deployable boom structures

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    An apparatus was developed for thermal distortion measurements on deployable boom structures. The calibration procedure and thermal static bending plus twist measurements are considered. The thermal mechanics test facility is described. A table is presented for several examples of spacecraft applications of thermal static distortion measurements on 3-m deployable booms
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