Study of passive temperature and humidity control systems for advanced space suits Materials research report, 1 Jul. 1967 - 1 Sep. 1968

Study of passive temperature and humidity control systems for extravehicular space suit

Feasibility study of integral heat sink space suit concepts

Integral heat sink material space suit for body temperature contro

Optimal Agricultural Production and Trade: Implications on International Competitiveness

International Relations/Trade,

Effects of turbulence in the atmosphere of Venus on Pioneer Venus radio, phase 2

Two problems related to the effects of turbulence in the atmosphere of Venus on the Pioneer entry probe radio link were studied. In the first problem, the cross correlation between the log amplitude and phase fluctuations of the Pioneer Venus communications link is examined. Data show that for fluctuation frequencies above approximately 1 Hz there is little or no correlation. For frequencies below this region the correlation is weak and the square root of the coherence has a peak value close to 0.65. The second problem consists of interferring turbulence characteristics of the Venus atmosphere from the Mariner 5 phase fluctuations. Data show that with the data processing techniques developed and currently available, the phase error due to oscillator drift, assumed trajectory delay, and spline curve fit exceed the turbulence induced fluctuations. Results show that it is not possible to interfere with the turbulence characteristics from Mariner 5 phase fluctuations

Origin of Anomalous Water Permeation through Graphene Oxide Membrane

Water inside the low dimensional carbon structures has been considered seriously owing to fundamental interest in its flow and structures as well as its practical impact. Recently, the anomalous perfect penetration of water through graphene oxide membrane was demonstrated although the membrane was impenetrable for other liquids and even gases. The unusual auxetic behavior of graphene oxide in the presence of water was also reported. Here, based on first-principles calculations, we establish atomistic models for hybrid systems composed of water and graphene oxides revealing the anomalous water behavior inside the stacked graphene oxides. We show that formation of hexagonal ice bilayer in between the flakes as well as melting transition of ice at the edges of flakes are crucial to realize the perfect water permeation across the whole stacked structures. The distance between adjacent layers that can be controlled either by oxygen reduction process or pressure is shown to determine the water flow thus highlighting a unique water dynamics in randomly connected two-dimensional spaces.Comment: 5 pages, 4 figures, to appear in Nano Letter

Ultracold Dipolar Gas of Fermionic 23^{23}Na40^{40}K Molecules in their Absolute Ground State

We report on the creation of an ultracold dipolar gas of fermionic $^{23}$Na$^{40}$K molecules in their absolute rovibrational and hyperfine ground state. Starting from weakly bound Feshbach molecules, we demonstrate hyperfine resolved two-photon transfer into the singlet ${\rm X}^1\Sigma^+ |v{=}0,J{=}0\rangle$ ground state, coherently bridging a binding energy difference of 0.65 eV via stimulated rapid adiabatic passage. The spin-polarized, nearly quantum degenerate molecular gas displays a lifetime longer than 2.5 s, highlighting NaK's stability against two-body chemical reactions. A homogeneous electric field is applied to induce a dipole moment of up to 0.8 Debye. With these advances, the exploration of many-body physics with strongly dipolar Fermi gases of $^{23}$Na$^{40}$K molecules is in experimental reach.Comment: 5 pages, 5 figure

Two-Photon Pathway to Ultracold Ground State Molecules of 23^{23}Na40^{40}K

We report on high-resolution spectroscopy of ultracold fermionic \nak~Feshbach molecules, and identify a two-photon pathway to the rovibrational singlet ground state via a resonantly mixed \Bcres intermediate state. Photoassociation in a $^{23}$Na-$^{40}$K atomic mixture and one-photon spectroscopy on \nak~Feshbach molecules reveal about 20 vibrational levels of the electronically excited \ctrip state. Two of these levels are found to be strongly perturbed by nearby \Bsing states via spin-orbit coupling, resulting in additional lines of dominant singlet character in the perturbed complex {${\rm B}^1\Pi |v{=}4\rangle {\sim} {\rm c}^3\Sigma^+ | v{=}25\rangle$}, or of resonantly mixed character in {${\rm B}^1\Pi | v{=}12 \rangle {\sim}{\rm c}^3\Sigma^+ | v{=}35 \rangle$}. The dominantly singlet level is used to locate the absolute rovibrational singlet ground state ${\rm X}^1\Sigma^+ | v{=}0, J{=}0 \rangle$ via Autler-Townes spectroscopy. We demonstrate coherent two-photon coupling via dark state spectroscopy between the predominantly triplet Feshbach molecular state and the singlet ground state. Its binding energy is measured to be 5212.0447(1) \cm, a thousand-fold improvement in accuracy compared to previous determinations. In their absolute singlet ground state, \nak~molecules are chemically stable under binary collisions and possess a large electric dipole moment of $2.72$ Debye. Our work thus paves the way towards the creation of strongly dipolar Fermi gases of NaK molecules.Comment: 23 pages, 8 figure

Technology study of passive control of humidity in space suits

Water vapor condensation and adsorption techniques for passive humidity control in space suit