Mean and fluctuating velocity contours and acoustic characteristics of subsonic and supersonic jets

Shadowgraph photographs of subsonic and supersonic jet

Forbidden Transitions in a Magneto-Optical Trap

We report the first observation of a non-dipole transition in an ultra-cold atomic vapor. We excite the 3P-4P electric quadrupole (E2) transition in $^{23}$Na confined in a Magneto-Optical Trap(MOT), and demonstrate its application to high-resolution spectroscopy by making the first measurement of the hyperfine structure of the 4P$_{1/2}$ level and extracting the magnetic dipole constant A $=$ 30.6 $\pm$ 0.1 MHz. We use cw OODR (Optical-Optical Double Resonance) accompanied by photoinization to probe the transition

Analysis of polynomial functions for determining maximum or minimum conditions in biological systems

1. When physiological condition is curvilinearly related to environmental conditions, the "optimum" environmental condition is frequently determined by intersecting two straight lines.2. Errors in this method are discussed, and a more precise method is suggested.3. The curvilinear function is described by polynomial regression.4. Optimum values of the independent variable (i.e. those resulting in maximum or minimum physiological responses) are found where the slope is zero, and can be calculated easily from the first derivative of the regression line.5. Two examples are given: heart rate-temperature and oxygen consumption-pH.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/22151/1/0000582.pd

Solvent extraction studies of coprocessing flowsheets: Results from Campaign 6 of the Solvent Extraction Test Facility (SETF)

A series of five solvent extraction tests were made in the Solvent Extraction Test Facility (SETF) during Campaign 6. Each test used a coprocessing flowsheet that included coextraction-coscrubbing of the heavy metals followed by partial partitioning of the uranium and plutonium into separate uranium and uranium-plutonium products. The separation of the uranium and plutonium was aided by the addition of HNO{sub 2} to the organic backscrub stream. Two of these tests compared the performance of the traditional Purex solvent, tri-n-butyl phosphate (TBP), with a potential replacement, tri-2-ethylhexyl phosphate (TEHP). The remaining three tests were made with a chemically-degraded TBP solvent to compare the effectiveness of two solvent cleanup methods - treatment with silica gel or scrubbing with sodium carbonate and water

Solvent extraction studies of coprocessing flowsheets: results from Campaign 5 of the Solvent Extraction Test Facility (SETF)

In Campaign 5, fast breeder reactor (FBR) fuel [average burnup {similar_to}2.6 TJ/kg ({similar_to}30,000 MWd/t)] was processed for the first time. Operations in a single extraction cycle with 30% TBP-NPH were satisfactory with low heavy-metal losses (< 0.02%) and high decontamination factors (DFs > 1000) for all fission products except {sup 95}Zr, which exhibited moderate DFs (180 and 750, respectively, in two runs). The use of a split scrub stream (0.5 M and 3 M HNO{sub 3}) vs a single scrub stream (3 M HNO{sub 3}) resulted in the higher DF. An extractant backscrubbing stream was not needed to produce partially partitioned uranium-plutonium products containing 30 to 35% plutonium when processing the core FBR fuel (22% Pu). The necessary enrichment factor ({similar_to}1.5) was attained by maintaining the temperature at 25 to 30{sup 0}C in partial partitioning and adjusting the relative flow rates of the aqueous and organic phases. The plutonium recovery in the two runs ({similar_to}400 g) was purified by anion exchange and converted to PuO{sub 2} for fuel refabrication studies. 8 references, 7 figures, 6 tables

Observation of anomalous spin-state segregation in a trapped ultra-cold vapor

We observe counter-intuitive spin segregation in an inhomogeneous sample of ultra-cold, non-condensed Rubidium atoms in a magnetic trap. We use spatially selective microwave spectroscopy to verify a model that accounts for the differential forces on two internal spin states. In any simple understanding of the cloud dynamics, the forces are far too small to account for the dramatic transient spin polarizations observed. The underlying mechanism remains to be elucidated.Comment: 5 pages, 3 figure

LegacyClimate 1.0: a dataset of pollen-based climate reconstructions from 2594 Northern Hemisphere sites covering the last 30 kyr and beyond

Here we describe LegacyClimate 1.0, a dataset of the reconstruction of the mean July temperature (TJuly), mean annual temperature (Tann), and annual precipitation (Pann) from 2594 fossil pollen records from the Northern Hemisphere, spanning the entire Holocene, with some records reaching back to the Last Glacial Period. Two reconstruction methods, the modern analog technique (MAT) and weighted averaging partial least squares regression (WA-PLS), reveal similar results regarding spatial and temporal patterns. To reduce the impact of precipitation on temperature reconstruction, and vice versa, we also provide reconstructions using tailored modern pollen data, limiting the range of the corresponding other climate variables. We assess the reliability of the reconstructions, using information from the spatial distributions of the root mean squared error in the prediction and reconstruction significance tests. The dataset is beneficial for synthesis studies of proxy-based reconstructions and to evaluate the output of climate models and thus help to improve the models themselves. We provide our compilation of reconstructed TJuly, Tann, and Pann as open-access datasets at PANGAEA (https://doi.org/10.1594/PANGAEA.930512; Herzschuh et al., 2023a). The R code for the reconstructions is provided at Zenodo (https://doi.org/10.5281/zenodo.7887565; Herzschuh et al., 2023b), including the harmonized open-access modern and fossil datasets used for the reconstructions, so that customized reconstructions can be easily established

Interglacial extension of the boreal forest limit in the Noatak Valley, northwest Alaska: Evidence from an exhumed river-cut bluff and debris apron

Numerous exposures of Pleistocene sediments occur in the Noatak basin, which extends for 130 km along the Noatak River in northwestern Alaska. Nk-37, an extensive bluff exposure near the west end of the basin, contains a record of at least three glacial advances separated by interglacial and interstadial deposits. An ancient river-cut bluff and associated debris apron is exposed in profile through the central part of Nk-37. The debris apron contains a rich biotic record and represents part of an interglaciation that is probably assignable to marine-isotope stage 5. Pollen spectra from the lower part of the debris apron closely resemble modern samples taken from the Noatak floodplain in spruce gallery forest, and macrofossils of spruce are also present at this level. Fossil bark beetles and carpenter ants occur higher in the debris apron. Mutual Climatic Range (MCR) estimates from the fossil beetles suggest temperatures similar to or warmer than today. Together, these fossils indicate the presence of an interglacial spruce forest in the western part of the Noatak Basin, which lies about 80 km upstream of the modem limit of spruce forest

Watching a superfluid untwist itself: Recurrence of Rabi oscillations in a Bose-Einstein condensate

The order parameter of a condensate with two internal states can continuously distort in such a way as to remove twists that have been imposed along its length. We observe this effect experimentally in the collapse and recurrence of Rabi oscillations in a magnetically trapped, two-component Bose-Einstein condensate of ^87Rb

Solvent extraction studies of coprocessing flowsheets: results from campaigns 3 and 4 of the Solvent-Extraction Test Facility (SETF)

Experiments on tri-n-butyl phosphate solvent extraction of uranium and plutonium at full activity levels (Campaigns 3 and 4) were conducted in the Solvent Extraction Test Facility (SETF), located in one of the heavily shielded cells of the Transuranium Processing Plant. The primary objectives were: (1) to demonstrate and evaluate the first two cycles of the Hot Engineering Facility flowsheets (codecontamination and partial partitioning), and (2) to investigate and evaluate the use of HNO{sub 2} as the reductant for tetravalent plutonium during reductive stripping operations. Secondary objectives were to determine the solvent extraction behavior of feed solutions prepared by dissolving fuel from a boiling water reactor (BWR) and to improve the solvent extraction feed clarification