3,253 research outputs found
Pb-Zn liquid metal diffusion
The Lead-Zinc binary equilibrium system is currently being investigated. Ground based studies of this system were performed to examine the possibility of obtaining a couple which, after diffusion, could be examined continuously along the diffusion axis by quantitative metallography to determine the extent of diffusion. The specimens were analyzed by X-ray fluorescence in the scanning electron microscope to provide exact information on the chemical composition gradient. Two diffusion experiments were run simultaneously in the multipurpose furnace, each in its own isothermal cavity. Two flight samples, two flight backup samples, and two flight space samples were generated
Alien Registration- Pond, Hulda M. (Hampden, Penobscot County)
https://digitalmaine.com/alien_docs/8224/thumbnail.jp
BLOOD-MEAL PREFERENCE OF AEDES AGEYPTI (DIPTERA: CULICIDAE) TO RESOURCES TREATED WITH THE TOXIN PRODUCED BY MYCOBACTERIUM ULCERANS
Mycolactone is a unique toxin produced by Mycobacterium ulcerans (MU), the causative agent of Buruli ulcer. The primary vector for Buruli ulcer (BU) is still unknown; however, some hypothesize mosquitoes, such as Aedes aegypti, could be the culprit due to their high vector competence with other pathogens and association with environments endemic to BU. Through a simple attraction test, supplemented with Evans Blue dye in blood to distinguish blood meal sites, the affinity for A. aegypti to take a blood meal successfully from a mycolactone saturated area was evaluated and these results show that there is a higher attraction for the control blood meal site in the lowest and highest dose, 0.05 μg/mL and 1.0 μg/mL respectively, and a higher attraction for the treatment blood meal site in the mid-level dose of 0.5 μg/mL. These results thus explore the possibility of interkingdom communication between mycolactone and A. aegypti. Additionally, this research will test the possibility that A. aegypti could help in spreading Buruli ulcer or causing secondary infection in people infected with BU with another disease in which they are the primary vector
Thermal and convection analyses of the dendrite remelting rocket experiment; Experiment 74-21 in the space processing rocket program
The Dendrite Remelting Rocket Experiment was performed aboard a Black Brant VC Sounding Rocket during a period which gravity levels of approximately 0.00001 g prevailed. The experiment consisted of cooling an aqueous ammonium chloride solution in a manner such that crystallization of ammonium chloride crystals proceeded throughout a three minute period of zero-g. The crystallization process during flight was recorded on 35 mm panatomic-x film. A number of ground crystallizations were similarly recorded for comparison purposes. The convective and thermal conditions in aqueous and metallic liquid systems were assessed under conditions of the flight experiment to help establish the relevance of the rocket experiment to metals casting phenomena. The results indicate that aqueous or metallic convective velocities in the Dendrite Remelting Rocket Experiment cell are of insignificant magnitudes at the 0.0001 to 0.00001 g levels of the experiment. The crystallization phenomena observed in the Rocket Experiment, therefore, may be indicative of how metals will solidify in low-g
Composition and concentration anomalies for structure and dynamics of Gaussian-core mixtures
We report molecular dynamics simulation results for two-component fluid
mixtures of Gaussian-core particles, focusing on how tracer diffusivities and
static pair correlations depend on temperature, particle concentration, and
composition. At low particle concentrations, these systems behave like simple
atomic mixtures. However, for intermediate concentrations, the single-particle
dynamics of the two species largely decouple, giving rise to the following
anomalous trends. Increasing either the concentration of the fluid (at fixed
composition) or the mole fraction of the larger particles (at fixed particle
concentration) enhances the tracer diffusivity of the larger particles, but
decreases that of the smaller particles. In fact, at sufficiently high particle
concentrations, the larger particles exhibit higher mobility than the smaller
particles. Each of these dynamic behaviors is accompanied by a corresponding
structural trend that characterizes how either concentration or composition
affects the strength of the static pair correlations. Specifically, the dynamic
trends observed here are consistent with a single empirical scaling law that
relates an appropriately normalized tracer diffusivity to its pair-correlation
contribution to the excess entropy.Comment: 5 pages, 4 figure
The Sommerfeld half-plane problem revisited, IV: Variations on a theme of Carlson and Heins
A plane wave is incident upon an infinite set of equally spaced, semi-infinite parallel and staggered plates. The boundary conditions on the plates alternate between the Dirichlet and Neumann ones. This problem is formulated as a pair of coupled Wiener-Hopf integral equations and solved by a method proposed by A. E. Heins in 1950. For the case of specular reflection, that is, a single reflected plane wave, the magnitudes of the reflection coefficient and the transmission coefficients are determined.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/50172/1/1670100307_ftp.pd
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