Global ETD Search
Search theses and dissertations gathered from participating repositories worldwide. Every result links back to the library that holds it. No account is needed.
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Showing 1 to 20 of 89 for “"impactor"”.
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Size-Dependent Earth Impactor Warning Times And Corresponding Campaign Mission Recommendations
<p>NASA seeks to reliably detect potential Earth Impactors (EI) in time to defend the planet by deflecting them. Congress has given an unfunded mandate to NASA to lead Spaceguard, a coalition of worldwide observatories and scientists who find, track, and determine impact probabilities for potential …
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Electron microscopic analyses of impactor samples from underground dieselized coal mines
Includes bibliographical references.
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Development and implementation of a microresonator impactor for atmospheric particulate sensing
… To this end, a new microresonator-based impactor was developed - the MEMS Impactor Stage (MIS) - capable of accommodating various nozzle and resonator combinations. Square lateral bulk acoustic resonators were the primary topology, but the results within the thesis are widely applicable. …
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Impact resistance of foamed concrete slab and its modifications subjected to hemispherical impactor
… The slab target subjected to hemispherical impactor with 7.7, 8.9 and 9.9 m/s impact velocity produced the crater without spalling or scabbing. This impact phenomenon was due to effect of porosity in matrix of foamed concrete and its modifications as foam material. Foamed concrete …
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Characterization of a 3D printed pumped counterflow virtual impactor and an aerodynamic lens concentrator
… sampling devices, the pumped counterflow virtual impactor (PCVI) and aerodynamic lens concentrator (ADL), were modelled using computer aided design software and printed using stereolithography printing. These devices were compared against their industrial counterparts. The printed PCVI was proven …
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Development and Evaluation of a Small Volume Liquid Impaction Surface (SVLIS) in the Next Generation Impactor (NGI)
… Impaction Surface (SVLIS) in the Next Generation Impactor (NGI), a cascade impactor for evaluation of aerodynamic particle size distribution. This SVLIS modified NGI allowed for incorporation of lung cell cultures or drug dissolution of orally inhaled powders following aerosolization.|A custom …
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Modification of the Next Generation Impactor and Incorporation of Bacterial Cultures as an In Vitro Pneumonia Model
… (LVLIS) incorporated into the Next Generation Impactor (NGI). This model allowed for the correlation of deposition and aerodynamic parameters of an antibiotic solution and antibacterial effects. Amberlite® beads were incorporated into the model to absorb the antibiotic so that time kill studies …
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Developing a method to sample potential resuspension of radioactive contaminants near the former Rocky Flats Technical Plant
… to particle size fraction, the use of a cascade impactor to separate aerosols by size can be utilized to relate how deep varied-sized particles might penetrate the human respiratory tract after inhalation. This would not only indicate the presence of radionuclides but also the deposition location …
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The Early Evolution of Terrestrial Planets: Impact Simulations and Planetary Chemistry
… reduced metallic iron cores of these large impactors are key to such processes, as are the vast sums of energy that such impacts deliver. In this thesis, we explore the environments of such scenarios in the aftermath of impacts, modelling the chemical state of the interacting atmosphere and …
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The Formation of Distal Impact Ejecta
… we create a method to estimate the size of an impactor and impact velocity required to create a spherule layer. The impactor size depends on the thickness of the layer and the impact velocity depends on the size of the spherules within the layer. Using observations of known spherule layers</p> …
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INFLUENCE OF ELECTROSTATIC CHARGE UPON THE DEPOSITION BEHAVIOR OF PHARMACEUTICAL AEROSOLS WITHIN CASCADE IMPACTORS
Cascade impactors, routinely used for in vitro particle size characterization of pharmaceutical aerosols, are calibrated using dilute, charge-neutralized, monodisperse aerosols. But pharmaceutical aerosols are known to generate concentrated, inherently charged, polydisperse aerosol clouds. A …
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Magnetized models for the formation of the moon
… the origin of the Moon suggests that a planetary impactor struck the proto-Earth in an oblique collision shortly after the formation of the solar system. The giant impact produces liquid and vapor debris, drawn from the proto-Earth and impactor. The debris either escapes the system, falls back to …
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The phase separation inlet for droplets, ice residuals, and interstitial aerosols
… inlet, a Large-Pumped Counterflow Virtual Impactor (L-PCVI), a flow tube as evaporation chamber, and a Pumped Counterflow Virtual Impactor (PCVI) to separate droplets, ice crystals, and interstitial aerosols for simultaneous sampling. Verification tests of each individual component of …
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An investigation of the forces within the tibiae at typical blast loading rates : with different boots
… loading conditions using the Modified Lower Limb Impactor. The impact tests were conducted using a lower limb impactor with the leg mounted vertically and attached to the knee of the Anthropomorphic Test Device (ATD). The MiL-Lx leg is a recently developed surrogate which has limited evaluation …
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Low-velocity Impact Analysis of Composite Repair Patches of Different Shapes
… study was performed considering the change in impactor speed and impactor material on the impact damage. Thus, this research work readily demonstrates the effectiveness of finite element analysis of low velocity impact.</p>
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Low rare earth element concentration impact glass from the K/T Boundary at Beloc
… there is only one case of a piece of the impactor being found (Kyte et al., 1995). Impact glass from the K/T boundary at Beloc, Haiti has been widely researched with several types of glass documented. So far, all of the documented glass exhibits a crustal REE compositional pattern. In this …
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Impact cratering with yield-stress fluids
… drop impacting a water pool, in most works the impactor is a solid, non-deformable sphere. However, in the relevant geological process, and in most other applications, both target and impactor are deformable. Also, the material used in lab experiments to mimic the relevant geological process …
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Characterization and Concentration of Particulate Matters Emitted From Confinement Animal Buildings
… were performed using a six-stage cascade impactor from nine different animal farms (swine finishing, farrowing, and layer hen housing). The measured bioaerosol concentrations varied from 12,000 to 28,000 CFU/m3 showing seasonal variation from each animal facility. The seasonal variation of …
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The influences of string tension and frame stiffness on racquet and ball motions, and on impact loads at the elbow joint during the tennis backhand drive
… change of an accelerometer instrumented impactor pendulum, and the strain-time change of the frame during the clamped racket impact. The impulsive loads acting on the elbow joint were estimated by adopting an inverse dynamic analysis (impulse-momentum equation) for the racket and forearm …
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