11,387 research outputs found
Orbit, reentry, and landing attachment for globes
Navigational device, invented to aid recovery of spacecraft from any orbit, also illustrates motions of satellites relative to earth and their entry-ranging requirements. Device rapidly and accurately defines lateral range requirements for spacecraft returning to any desired site without manual or computerized calculation of orbital equations of motion
Space station needs, attributes, and architectural options. Volume 1. Executive summary
The initial space station should be manned, placed in 28.5 deg orbit, and provide substantial economic, performance, and social benefits. The most beneficial space station capabilities include: a space test facility; a transport harbor; satellite servicing and assembly; and an observatory. A space industrial park could be added once further development effort validates the cost and expanding commercial market for space processed materials. The potential accrued gross mission model benefit derived from these capabilities is 9.3B with it. An unclassified overview of all phases of the study is presented
The orbital recovery problem. Part II - Application of analysis technique to selection of recovery sites for return from low circular orbits
Lateral range requirements used in selecting spacecraft landing recovery sites for return from low circular orbit
Letter from B. Pritchard to James B. Finley
Pritchard sent a box of Grand Division Regalia to Samuel Galloway for use at the Grand Division meeting in Springfield. Galloway failed to acknowledge receipt of the box. Pritchard enlists Finley\u27s aid to determine whether the regalia arrived in time, and where it is currently located. He asks Finley to forward the regalia to him in Zanesville before April 25th. Abstract Number - 1220https://digitalcommons.owu.edu/finley-letters/2200/thumbnail.jp
Potential use of thermally desorbed soil as a partial cement replacement
The industrial heritage of the UK has given rise to around 100,000 sites, being classified as contaminated. There are many different techniques that have recently been developed to remediate land. Thermal desorption is one of these techniques. Contaminants in the soil are volatilised, which are then removed by a thermal or catalytic oxidiser. The chemical and physical properties of the ‘burnt’ soil’, termed thermally desorbed soil (TDS), have significantly changed but is typically still disposed of to landfill. The use of supplementary cementing materials has become a central aspect of construction economics and environmental preservation. This study therefore investigated the potential use of TDS as a partial cement replacement material. Cement was replaced from 0% (as the control) to 30% TDS in 10% increments. The compressive strength of the mortar cubes was then determined at intervals of 7, 28 and 91 days. For a direct comparison, a well-established pozzolanic material, fly ash (FA) was tested throughout the programme. Strength was indirectly related to replacement level, with the control initially (up to 7 days) gaining, and thereafter retaining, the highest degree of strength. However, after 7 days the rate of gain in strength was higher for the replacement mixes (FA and TDS) than the control. There was no significant strength difference between the FA and TDS mixes up to 20% replacement. Hence, based on these initial strength results, the performance of TDS as a partial cement replacement (up to 20%) was directly equivalent to that of FA. Environmental benefits for the use of TDS as a partial cement replacement would be twofold; firstly, by using a waste material rather than disposing to landfill; and secondly by using less cement. This would result in less carbon dioxide (CO2) being released into the atmosphere during the cement manufacturing process, which is currently responsible for 7–10% of the global CO2 emissions
SUIZA FOODS CORPORATION: BEST MANAGEMENT STRATEGY IN THE FLUID MILK INDUSTRY
Suiza Foods has rapidly grown to become the largest company in the U.S. fluid milk industry. This teaching case is designed to familiarize students with the challenges which confront Suiza in its quest for further growth and, in turn, high profitability. Interviews with top executives describe the history of Suiza as well as the rationale behind Suiza's strategies. Information is presented on both economic and financial trends so as to allow the student to asses Suiza's past, present and future performance.Agribusiness, Livestock Production/Industries,
Detecting the redshifted 21cm forest during reionization
The 21cm forest -- HI absorption features in the spectra of high-redshift
radio sources -- can potentially provide a unique probe of the largely neutral
intergalactic medium (IGM) during the epoch of reionization. We present
simulations of the 21cm forest due to the large scale structure of the
reionization-era IGM, including a prescription for x-ray heating and the
percolation of photoionization bubbles. We show that, if detected with future
instruments such as the Square Kilometer Array (SKA), the 21cm forest can
provide a significant constraint on the thermal history of the IGM. Detection
will be aided by consideration of the sudden increase in signal variance at the
onset of 21cm absorption. If radio foregrounds and the intrinsic source spectra
are well understood, the flux decrement over wide bandwidths can also improve
detection prospects. Our analysis accounts for the possibility of narrow
absorption lines from intervening dense regions, but, unlike previous studies,
our results do not depend on their properties. Assuming x-ray heating
corresponding to a local stellar population, we estimate that a statistically
significant detection of 21cm absorption could be made by SKA in less than a
year of observing against a Cygnus A-type source at , as opposed to
nearly a decade for a significant detection of the detailed forest features. We
discuss observational challenges due to uncertainties regarding the abundance
of background sources and the strength of the 21cm absorption signal.Comment: Submitted to MNRAS. Revised version includes updated and extended
calculations, some corrections and added reference
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