4,811 research outputs found

    Innovative techniques for the production of energetic radicals for lunar processing including cold plasma processing of local planetary ores

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    Hydrogen reduction of ilmenite has been studied by a number of investigators as a potential means for recovery of oxygen from lunar soil. Interest in this process has always rested with the simplicity of the flow diagram and the utilization of established technology. Effective utilization of hydrogen in the reduction process at temperatures of 1200 C and below has always been disappointing and, as such, has led other investigators to focus attention on other systems. Effective utilization of hydrogen in the reduction of ilmenite can be significantly enhanced in the presence of a non-equilibrium hydrogen plasma. Ilmenite at solid specimen temperatures of 600 C to 970 C were reacted in a hydrogen plasma. Those experiments revealed that hydrogen utilization can be significantly enhanced. At a specimen temperature of 850 C the fraction of H2 reacted was 24 percent compared to the 7 percent theoretical limit calculated with thermodynamic theory for the same temperature. An added advantage for a hydrogen plasma involves further reduction of TiO2. Reduction of the iron oxide in ilmenite yields TiO2 and metallic iron as by products. Titanium forms a number of oxides including TiO, Ti2O3, Ti3O5 and the Magneli oxides (Ti4O7 to Ti50O99). In conventional processing of ilmenite with hydrogen it is possible to reduce TiO2 to Ti7O13 within approximately an hour, but with poor utilization of hydrogen on the order of one mole of H2 per thousand. In the cold or non-equilibrium plasma TiO2 can be rapidly reduced to Ti2O3 with hydrogen utilization exceeding 10 percent. Based on design considerations of the plasma reactor greater utilization of the hydrogen in the reduction of TiO2 is possible

    Intermediaries and payments instruments

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    We study an economy in which intermediaries have incentives to issue circulating liabilities as part of an equilibrium. We show that, with arbitrarily small transactions costs, only the liabilities of intermediaries will circulate, and not those of other private sector agents. Therefore, our model connects intermediation activity with the issuance of payments media, a connection that has not been made in earlier literature. We also describe conditions under which equilibrium outcomes may be volatile when private liabilities circulate. Finally, we use our model to suggest a resolution of the "banknote underissue puzzle" of Cagan (1993).Monetary policy ; Bank notes ; Payment systems

    The value of inside and outside money: expanded version

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    We study dynamic economies in which agents may have incentives to hold both privately-issued (a.k.a. inside) and publicly-issued (a.k.a. outside) circulating liabilities as part of an equilibrium. Our analysis emphasizes spatial separation and limited communication as frictions that motivate monetary exchange. We isolate conditions under which a combination of inside and outside money does and does not allow the economy to achieve a first-best allocation of resources. We also study the extent to which the use of private circulating liabilities alone, or the use of public circulating liabilities alone, can address the frictions that lead to monetary exchange. We identify conditions under which both types of liabilities are essential to efficiency. However, even when these conditions are satisfied, we show that political economy considerations may lead to a prohibition against private circulating liabilities. Finally, we analyze the consequences of such a prohibition for the determinacy of equilibrium, and for endogenously arising volatility.Money ; Money theory

    The value of inside and outside money

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    We study dynamic economies in which agents may have incentives to hold both privately-issued (a.k.a. inside) and publicly-issued (a.k.a. outside) circulating liabilities as part of an equilibrium. Our analysis emphasizes spatial separation and limited communication as frictions that motivate monetary exchange. We isolate conditions under which a combination of inside and outside money does and does not allow the economy to achieve a first-best allocation of resources. We also study the extent to which the use of private circulating liabilities alone, or the use of public circulating liabilities alone, can address the frictions that lead to monetary exchange. We identify conditions under which both types of liabilities are essential to efficiency. However, even when these conditions are satisfied, we show that political economy considerations may lead to a prohibition against private circulating liabilities. Finally, we analyze the consequences of such a prohibition for the determinacy of equilibrium, and for endogenously arising volatility.Money ; Money theory

    Cold plasma processing of local planetary ores for oxygen and metallurgically important metals

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    The utilization of a cold plasma in chlorination processing is described. Essential equipment and instruments were received, the experimental apparatus assembled and tested, and preliminary experiments conducted. The results of the latter lend support to the original hypothesis: a cold plasma can both significantly enhance and bias chemical reactions. In two separate experiments, a cold plasma was used to reduce TiCl4 vapor and chlorinate ilmenite. The latter, reacted in an argon-chlorine plasma, yielded oxygen. The former experiment reveals that chlorine can be recovered as HCl vapor from metal chlorides in a hydrogen plasma. Furthermore, the success of the hydrogen experiments has lead to an analysis of the feasibility of direct hydrogen reduction of metal oxides in a cold plasma. That process would produce water vapor and numerous metal by-products

    Cold plasma processing of local planetary ores for oxygen and metallurgically important metals

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    The utilization of a cold or nonequilibrium plasma in chlorination processing is discussed. Titanium dioxide (TiO2) was successfully chlorinated at temperatures between 700 and 900 C without the aid of carbon. In addition to these initial experiments, a technique was developed for determining the temperature of a specimen in a plasma. Development of that technique has required evaluating the emissivity of TiO2, ZrO2, and FeOTiO2 and analyzing the specimen temperature in a plasma as a function of both power absorbed by the plasma and the pressure of the plasma. The mass spectrometer was also calibrated with TiCl4 and CCl4 vapor

    In the Wake of the Storm: Environment, Disaster, and Race After Katrina

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    Studies evidence of environmental disparities by which poor and minority communities are disproportionately exposed to disasters, are less prepared, and have less access to relief agencies. Makes recommendations for preparedness and environmental justice

    History and evaluation of the McIntire-Stennis Cooperative Forestry Research Program

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    On October 10, 1962, President John Kennedy signed PL 87-788 (Appendix A) now known as the McIntire-Stennis Cooperative Forestry Research Program. After 40 years, this formula-based cooperative program continues to provide the base support for much of the forestry research conducted at 65 public forestry institutions. While still important, the proportion of McIntire-Stennis research sponsored over this time period has decreased. Other funding sources, such as competitive grants through the Cooperative State Research, Education, and Extension Service and other government agencies along with special grants appropriated by Congress, now finance a higher proportion of forestry research as shown in Figure 1. The level of funding from non-federal sources has increased slightly. This evaluation is an attempt to determine whether the decline in support is due to an “internal” failure of the program to meet its goals and objectives or “external” pressures from influences of other more “popular” funding sources. Most of the forestry leaders who fought for its passage and implementation are now gone. Few today in forestry research know of the extensive efforts exerted by earlier forestry leaders to establish the McIntire-Stennis program. This history provides a tribute to the dedication of earlier forestry leaders, and at the same time, demonstrates a possible path for renewal of their efforts to increase the level of forestry research

    Kinematic dynamo action in a sphere: Effects of periodic time-dependent flows on solutions with axial dipole symmetry

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    Choosing a simple class of flows, with characteristics that may be present in the Earth's core, we study the ability to generate a magnetic field when the flow is permitted to oscillate periodically in time. The flow characteristics are parameterised by D, representing a differential rotation, M, a meridional circulation, and C, a component characterising convective rolls. Dynamo action is sensitive to these flow parameters and fails spectacularly for much of the parameter space where magnetic flux is concentrated into small regions. Oscillations of the flow are introduced by varying the flow parameters in time, defining a closed orbit in the space (D,M). Time-dependence appears to smooth out flux concentrations, often enhancing dynamo action. Dynamo action can be impaired, however, when flux concentrations of opposite signs occur close together as smoothing destroys the flux by cancellation. It is possible to produce geomagnetic-type reversals by making the orbit stray into a region where the steady flows generate oscillatory fields. In this case, however, dynamo action was not found to be enhanced by the time-dependence. A novel approach is taken to solving the time-dependent eigenvalue problem, where by combining Floquet theory with a matrix-free Krylov-subspace method we avoid large memory requirements for storing the matrix required by the standard approach.Comment: 22 pages, 12 figures. Geophys. Astrophys. Fluid Dynam., as accepted (2004

    Furniture manufacturing and marketing: Eight strategic issues for the 21st century

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    “Take change by the hand, or it will take you by the throat.” Attributed to Winston Churchill, this brief sentence emphasizes the need to understand and embrace change in general. What important “changes” will impact furniture production and marketing in the 21st century? And what can furniture manufacturers and marketers do to “take change by the hand” today and in the future
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