Outplayed: Regaining Strategic Initiative in the Gray Zone, A Report Sponsored by the Army Capabilities Integration Center in Coordination with Joint Staff J-39/Strategic Multi-Layer Assessment Branch

U.S. competitors pursuing meaningful revision or rejection of the current U.S.-led status quo are employing a host of hybrid methods to advance and secure interests contrary to those of the United States. These challengers employ unique combinations of influence, intimidation, coercion, and aggression to incrementally crowd out effective resistance, establish local or regional advantage, and manipulate risk perceptions in their favor. So far, the United States has not come up with a coherent countervailing approach. It is in this “gray zone”—the awkward and uncomfortable space between traditional conceptions of war and peace—where the United States and its defense enterprise face systemic challenges to U.S. position and authority. Gray zone competition and conflict present fundamental challenges to U.S. and partner security and, consequently, should be important pacers for U.S. defense strategy.https://press.armywarcollege.edu/monographs/1924/thumbnail.jp

Reduction of inherent mercury emissions in PC combustion. Semi-annual technical progress report No. 2, January 1, 1996--June 30, 1996

The 1990 Clean Air Act Amendments handed the utility industry a major challenge for the coming years. The legislation requires that the U.S. Environmental Protection Agency set emission standards for the 189 compounds or compound families identified in the act as air toxics. Evaluations by EPRI have identified 37 of these species as concerns in power generation. This research focuses on the air pollution control of mercury and rate limiting steps in mercury capture

Suppression of fine ash formation in pulverized coal flames. Quarterly technical progress report No. 5, October 1, 1993--December 31, 1993

Laboratory work and studies of full-scale coal-fired boilers have identified two general mechanisms for ash production. The vast majority of the ash is formed from mineral matter that coalesces as the char burns, yielding particles that are normally larger than 0.5{mu}m. Flagen and Friedlander proposed a simple model for this residual ash, called the breakup model. The second major mechanism is the generation of a submicron aerosol through a vaporization/condensation mechanism. When the ash size distribution is plotted in terms of number density, the submicron mode generally peaks at about 0.1 {mu}/m. When plotted in terms of mass, this mode is sometimes distinct from the residual ash mode, {sup 13} and sometimes merged into it. Although these particles represent a relatively small fraction of the mass, they can present a large fraction of the surface area. Thus, they are a preferred site for the condensation of the more volatile oxides later in the furnace. This leads to a layering effect in which the refractory oxides are concentrated at the particle core and the more volatile oxides reside at the surface. This also explains the enrichment of the aerosol by volatile oxides that has been noted in samples from practical furnaces. These volatile metal oxides include the majority of the toxic metal contaminants, e.g., mercury, arsenic, selenium and nickel. Risk assessment studies suggest that toxic metal emissions represent a significant portion of the health risk associated with combustion

Suppression of fine ash formation in pulverized coal flames. Quarterly technical progress report No. 2, January 1, 1993--March 31, 1993

The second major ash producing mechanism is the generation of a submicron aerosol through a vaporization/condensation mechanism. When the ash size distribution is plotted in terms of number density, the submicron mode generally peaks at about 0. 1 {mu}m. When plotted in terms of mass, this mode is sometimes distinct from the residual ash mode, and sometimes merged into it. During diffusion-limited char combustion, the interior of the particle becomes hot and fuel-rich. The non-volatile oxides (e.g., Al{sub 2}O{sub 3}, SiO{sub 2}, MgO, CaO, Fe{sub 2}O{sub 3}) can be reduced to more volatile suboxides and elements, and partially vaporized. These reoxidize while passing through the boundary layer surrounding the char particle, thus becoming so highly supersaturated that rapid homogeneous nucleation occurs. This high nuclei concentration in the boundary layer promotes more extensive coagulation than would occur if the nuclei were uniformly distributed across the flow field. The vaporization can be accelerated by the overshoot of the char temperature beyond the local gas temperature. Although these particles represent a relatively small fraction of the mass, they can present a large fraction of the surface area. Thus, they are a preferred site for the condensation of the more volatile oxides later in the furnace. This leads to a layering effect in which the refractory oxides are concentrated at the particle core and the more volatile oxides resideat the surface. This also explains the enrichment of the aerosol by volatile oxides that has been noted in samples from practical furnaces. These volatile metal oxides include the majority of the toxic metal contaminants, e.g., mercury, arsenic, selenium and nickel. Risk assessment studies suggest that toxic metal emissions represent a significant portion of the health risk associated with combustion systems

Suppression of fine ash formation in pulverized coal flames. Quarterly technical progress report No. 3, April 1, 1993--June 30, 1993

One of the major obstacles to the economical use of coal is managing the behavior of its mineral matter. Ash size and composition are of critical importance for a variety of reasons. Fly ash size and emissivity affect radiant furnace heat transfer. Heat transfer is also affected by the tendency of ash to adhere to heat transfer surfaces, and the properties of these deposits. Removal of ash from flue gas by electrostatic precipitators is influenced by both particle size and particle resistivity. The efficiency of fabric filter-based cleaning devices is also influenced by ash size. Both types of devices have reduced collection efficiencies for smaller-sized particles, which corresponds to the size most efficiently retained in the alveolar region of the human lung. Laboratory work and studies of full-scale coal-fired boilers have identified two general mechanisms for ash production. The vast majority of the ash is formed from mineral matter that coalesces as the char burns, yielding particles that are normally larger than 0.5 {mu}m. The second major mechanism is the generation of a submicron aerosol through a vaporization/condensation mechanism. Although these particles represent a relatively small fraction of the mass, they can present a large fraction of the surface area. Thus, they are a preferred site for the condensation of the more volatile oxides later in the furnace. This leads to a layering effect in which the refractory oxides are concentrated at the particle core and the more volatile oxides reside at the surface. This also explains the enrichment of the aerosol by volatile oxides that has been noted in samples from practical furnaces. These volatile metal oxides include the majority of the toxic metal contaminants, e.g., mercury, arsenic, selenium and nickel. Risk assessment studies suggest that toxic metal emissions represent a significant portion of the health risk associated with combustion

Suppression of fine ash formation in pulverized coal flames. Quarterly technical progress report No. 4, July 1, 1993--September 30, 1993

Laboratory work and studies of full-scale coal-fired boilers have identified two general mechanisms for ash production. The vast majority of the ash is formed from mineral matter that coalesces as the char burns, yielding particles that are normally larger than 0.5 {mu}m. The second major mechanism is the generation of a submicron aerosol through a vaporization/condensation mechanism. Previous work has shown that pulverized bituminous coals that were treated by coal cleaning (via froth flotation) or aerodynamic sizing exhibited altered aerosol emission characteristics. Specifically, the emissions of aerosol for the cleaned and sized coals increased by as much as one order of magnitude. The goals of the present progress are to: (1) perform measurements on carefully characterized coals to identify the means by which the coal treatment increases aerosol yields; (2) investigate means by which coal cleaning can be done in a way that will not increase aerosol yields; (3) identify whether this mechanism can be used to reduce aerosol yields from systems burning straight coal. This paper discusses model description and model formulation, and reports on the progress of furnace design and construction, and coal selection

Mechanisms governing fine particulate emissions from coal flames. Quarterly technical progress report No. 6, January 1, 1989--March 31, 1989

The overall objective of this project is to provide a basic understanding of the principal processes that govern fine particulate formation in pulverized coal flames. This understanding is to be sued to develop a model (or models) which will predict the yield and size distribution of fine particulate matter as a function of coal type, coal processing, and combustion conditions. The goal of the model is to provide an engineering tool that will enable the practitioner to estimate the consequences of deign decisions and fuel selection on the fine particulate yield. The practitioner can then make rational decisions regarding the required technology and costs associated with effluent cleanup while still in the design phase

Mechanisms governing fine particulate emissions from coal flames. Quarterly technical progress report No. 5, October 1, 1988--December 31, 1988

The overall objectives of this project are to provide a basic understanding of the principal processes that govern fine particulate formation in pulverized coal flames. This understanding is to be used to develop a model (or models) which will predict the yield and size distribution of fine particulates as a function of coal type, coal processing, and combustion conditions. The goal of the model is to provide an engineering tool that will enable the practitioner to estimate the consequences of design decisions and fuel selection on the fine particulate yield. The practitioner can then make rational decisions regarding the required technology and costs associated with effluent cleanup while still in the design phase