Conceptual design studies and experiments related to cavity exhaust systems for nuclear light bulb configurations

Investigations of various phases of gaseous nuclear rocket technology have been conducted. The principal research efforts have recently been directed toward the closed-cycle, vortex-stabilized nuclear light bulb engine and toward a small-scale fissioning uranium plasma experiment that could be conducted in the Los Alamos Scientific Laboratory's Nuclear Furnace. The engine concept is based on the transfer of energy by thermal radiation from gaseous fissioning uranium, through a transparent wall, to hydrogen propellant. The reference engine configuration is comprised of seven unit cavities, each having its own fuel transparent wall and propellant duct. The basic design of the engine is described. Subsequent studies performed to supplement and investigate the basic design are reported. Summaries of other nuclear light bulb research programs are included

Further research on instabilities in atmospheric flow systems associated with clear air turbulence

Fluid mechanics study of instabilities in atmospheric flow systems associated with clear air turbulenc

Etiology of Poverty: A Critical Evaluation of Two Major Theories

The purpose of this article is to appraise two competing frameworks related to poverty attribution: individualistic theories and structural theories. Using the Theory Evaluation Scale (TES)—an empirically validated nine-criterion measure—this paper scrutinizes the aforementioned theories for coherence, conceptual clarity, philosophical assumptions, connection with previous research, testability, empiricism, limitations, client context, and human agency. Results revealed that, at the scale level, both perspectives are of excellent quality. However, at the item-level, the structural perspective was found to be significantly stronger than the individual perspective. Therefore, the structural perspective is an epistemologically sounder framework for informing antipoverty interventions

Letter to the Editor

Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/72427/1/j.1746-1561.1970.tb05620.x.pd

Sudbury project (University of Muenster-Ontario Geological Survey): Petrology, chemistry, and origin of breccia formations

Within the Sudbury Project of the University of Muenster and the Ontario Geological Survey special emphasis was put on the breccia formations exposed at the Sudbury structure (SS) because of their crucial role for the impact hypothesis. They were mapped and sampled in selected areas of the north, east, and south ranges of the SS. The relative stratigraphic positions of these units are summarized. Selected samples were analyzed by optical microscopy, SEM, microprobe, XRF and INAA, Rb-Sr and SM-Nd-isotope geochemistry, and carbon isotope analysis. The results of petrographic and chemical analysis for those stratigraphic units that were considered the main structural elements of a large impact basin are summarized

Probing weak force induced parity violation by high resolution mid-infrared molecular spectroscopy

To date no experiment has reached the level of sensitivity required to observe weak nuclear force induced parity violation (PV) energy differences in chiral molecules. In this paper, we present the approach, adopted at Laboratoire de Physique des Lasers (LPL), to measure frequency differences in the vibrational spectrum of enantiomers. We review different spectroscopic methods developed at LPL leading to the highest resolutions, as well as 20 years of CO2 laser stabilization work enabling such precise measurements. After a first attempt to observe PV vibrational frequency shifts using sub-Doppler saturated absorption spectroscopy in a cell, we are currently aiming at an experiment based on Doppler-free two-photon Ramsey interferometry on a supersonic beam. We report on our latest progress towards observing PV with chiral organo-metallic complexes containing a heavy rhenium atom

Élaboration et caractérisation de nanocomposites polyéthylène/montmorillonite

Revue de littérature -- Objectifs et organisation générale du document -- Travaux préliminaires, partie 1 : élaboration de montmorillonites organophiles à haute stabilité thermique -- Travaux préliminaires, partie II : nanocomposites polyéthylène/montmorillonite : sélection des matériaux -- Article 1 : Thermal decomposition of various alkyl onium organoclays : effect on polyethylene terephtalate nanocomposites properties -- Article 2 : effect of intercalating agents on clay dispersion on the properties of LLDPE/LLDPE-G-MAH/Montmorillonite nanocomposites -- Discussion générale

Unidirectional spin-wave channeling along magnetic domain walls of Bloch type

From the pioneering work of Winter [Phys. Rev. 124, 452 (1961)], a magnetic domain wall of Bloch type is known to host a special wall-bound spin-wave mode, which corresponds to spin-waves being channeled along the magnetic texture. Using micromagnetic simulations, we investigate spin-waves travelling inside Bloch walls formed in thin magnetic media with perpendicular-to-plane magnetic anisotropy and we show that their propagation is actually strongly nonreciprocal, as a result of dynamic dipolar interactions. We investigate spin-wave non-reciprocity effects in single Bloch walls, which allows us to clearly pinpoint their origin, as well as in arrays of parallel walls in stripe domain configurations. For such arrays, a complex domain-wall-bound spin-wave band structure develops, some aspects of which can be understood qualitatively from the single-wall picture by considering that a wall array consists of a sequence of up/down and down/up walls with opposite non-reciprocities. Circumstances are identified in which the non-reciprocity is so extreme that spin-wave propagation inside individual walls becomes unidirectional.Comment: 7 pages, 5 figure