نتایج جستجو برای: plume
تعداد نتایج: 7494 فیلتر نتایج به سال:
Algorithms have been developed to support quantitative analysis of a gas plume using down-looking airborne hyperspectral long-wave infrared (LWIR) imagery. The resulting gas quantification “GQ” tool estimates the quantity of one or more gases at each pixel, and estimates uncertainty based on factors such as atmospheric transmittance, background clutter, and plume temperature contrast. GQ uses g...
Autonomous vehicles with plume tracing capabilities would be valuable for finding chemical sources in fluid flows. This article considers strategies allowing autonomous vehicles to find and trace an odor plume to its source. These strategies are inspired by the maneuvers of moths flying upwind along a pheromone plume. Although moth maneuvers are well documented, the mechanisms underlying sensor...
During airborne in situ measurements of particle size distributions in a forest fire plume originating in Northern Canada, an accumulation mode number mean diameter of 0.34 μm was observed over Lindenberg, Germany on 9 August 1998. Realizing that this is possibly the largest value observed for this property in a forest fire plume, scenarios of plume ageing by coagulation are considered to expla...
Detailed direct simulation Monte Carlo/Particle in Cell simulations involving the interaction of a hydrazine chemical rocket plume with the rarefied ambient magnetosphere are presented for steady thruster firings in geostationary Earth orbit (GEO). The hydrazine chemical rocket plume is modeled as a neutral gas mixture with thruster exit conditions corresponding to a mass flow rate of 5.0 × 10−...
A new Gaussian dispersion model, the Plume Rise Model Enhancements (PRIME), has been developed for plume rise and building downwash. PRIME considers the position of the stack relative to the building, streamline deflection near the building, and vertical wind speed shear and velocity deficit effects on plume rise. Within the wake created by a sharp-edged, rectangular building, PRIME explicitly ...
United States Environmental Protection Agency (USEPA) set opacity standards for visual emissions from industrial sources to protect ambient air quality. USEPA developed Method 9, which is a reference method to describe how plume opacity can be quantified by human observers during daytime conditions. However, it would be beneficial to determine plume opacity with digital still cameras (DSCs) to ...
We present Daysmoke, an empirical-statistical plume rise and dispersion model for simulating smoke from prescribed burns. Prescribed fires are characterized by complex plume structure including multiple-core updrafts which makes modeling with simple plume models difficult. Daysmoke accounts for plume structure in a three-dimensional veering/sheering atmospheric environment, multiple-core updraf...
In this work we report on progress in the development of models for a Micro-Pulsed Plasma Thruster (μPPT) and its exhaust plume. As a working example we consider a μPPT developed at the Air Force Research Laboratory. This is a miniaturized design of the axisymmetric PPT with a thrust in the 10 μN range that utilizes Teflon as a propellant. The plasma plume is simulated using a hybrid fluid-PIC-...
[1] A case of long-range transport of a biomass burning plume from Alaska to Europe is analyzed using a Lagrangian approach. This plume was sampled several times in the free troposphere over North America, the North Atlantic and Europe by three different aircraft during the IGAC Lagrangian 2K4 experiment which was part of the ICARTT/ ITOP measurement intensive in summer 2004. Measurements in th...
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