Characterization of H2O Transport Through Johnson Space Center Number 1A Lunar Regolith Simulant at Low Pressure for In-situ Resource Utilization - Data File

Data file contains the unprocessed numerical data and supplementary figures for the manuscript: G. L. Schieber, B. M. Jones, T. M. Orlando, and P. G. Loutzenhiser, (in press). Characterization of H2O transport through Johnson Space Center number 1A lunar regolith simulant at low pressure for in-situ resource utilization. Physics of Fluids. DOI: https://doi.org/10.1063/5.0042589H2O transport through a packed bed of Johnson Space Center number 1A (JSC-1A) lunar regolith simulant was examined at relevant temperatures and pressures for in-situ resource utilization (ISRU) on the Moon. Experimentation was conducted over a range of pressures from 50 to 2,065 Pa at ~350 K, corresponding to Knudsen numbers of 0.3 < Kn < 11 and relevant towards ISRU technologies. A piecewise function was used to evaluate transition and Knudsen regime flows. The piecewise model utilized a Knudsen number that predicted the transition point between advective and Knudsen flows. A transition Knudsen number of 1.66 ± 0.61 and a tortuosity shape parameter of 0.736 ± 0.13 were determined from non-linear regression, and Knudsen diffusivities of 10.62 cm2·s-1, 10.40 cm2·s-1 and 9.04 cm2·s-1 for packed beds of JSC-1A with porosities of 0.388, 0.385, and 0.365, respectively. The experimental measurements, methodology, and modeling provide useful information for ISRU technologies involving the transport of volatiles (e.g., thermal extraction of H2O).NASA Solar System Exploration Research Virtual Institute (SSERVI) NNA17BF68

Advection Diffusion Model for Gas Transport Within a Packed Bed of JSC-1A Regolith Simulant - Data File

Data files contain the unprocessed numerical data presented in the following manuscript. File names correspond to manuscript figures: Garrett L. Schieber, Brant M. Jones, Thomas M. Orlando, Peter G. Loutzenhiser. Acta Astronautica 2020 4 (169), 32-39. DOI: https://doi.org/10.1016/j.actaastro.2019.12.031The advection diffusion model was evaluated for gas transport within a packed bed of lunar JSC-1A regolith simulant at low to medium total pressures over three flow regimes: (1) the slip flow regime (2) the transition regime and (3) the Knudsen regime. These regimes are pertinent to the design of H2O extraction devices for in-situ resource utilization, sampling missions, and surface science. Experimentation was conducted over a range of average pressures of 100 to 25,000 Pa, corresponding to Knudsen numbers between 0.01 and 100 at ambient temperature with Ar and N2. Non-condensing, gases with ideal behavior were evaluated to isolate key flow properties as first step towards evaluating more complex H2O flows. Experimental results were coupled to physical models, and key properties were evaluated to assess the model fit. The experimental results in the transition regime followed the expected behavior based on similar works for microchannel flow and showed that advection is not negligible for transition regime flows. The advection diffusion model in the transition regime fit the results for Knudsen numbers less than unity, and showed the need to further develop gas slip models for Knudsen numbers greater than unity. Key parameters necessary to define were the porosity, tortuosity, pore diameter of the regolith medium, and the gas slip parameter was key in determining the gas-specific transport rate.NASA Solar System Exploration Research Virtual Institute (SSERVI) NNA17BF68

National health accounts data from 1996 to 2010: a systematic review

OBJECTIVE: To collect, compile and evaluate publicly available national health accounts (NHA) reports produced worldwide between 1996 and 2010. METHODS: We downloaded country-generated NHA reports from the World Health Organization global health expenditure database and the Organisation for Economic Co-operation and Development (OECD) StatExtract website. We also obtained reports from Abt Associates, through contacts in individual countries and through an online search. We compiled data in the four main types used in these reports: (i) financing source; (ii) financing agent; (iii) health function; and (iv) health provider. We combined and adjusted data to conform with OECD’s first edition of A system of health accounts manual, (2000). FINDINGS: We identified 872 NHA reports from 117 countries containing a total of 2936 matrices for the four data types. Most countries did not provide complete health expenditure data: only 252 of the 872 reports contained data in all four types. Thirty-eight countries reported an average not-specified-by-kind value greater than 20% for all data types and years. Some countries reported substantial year-on-year changes in both the level and composition of health expenditure that were probably produced by data-generation processes. All study data are publicly available at http://vizhub.healthdata.org/nha/. CONCLUSION: Data from NHA reports on health expenditure are often incomplete and, in some cases, of questionable quality. Better data would help finance ministries allocate resources to health systems, assist health ministries in allocating capital within the health sector and enable researchers to make accurate comparisons between health systems

Secular changes in sedimentation systems and sequence stratigraphy

The ephemeral nature of most sedimentation processes and the fragmentary character of the sedimentary record are of first-order importance. Despite a basic uniformity of external controls on sedimentation resulting in markedly similar lithologies, facies, facies associations and depositional elements within the rock record across time, there are a number of secular changes, particularly in rates and intensities of processes that resulted in contrasts between preserved Precambrian and Phanerozoic successions. Secular change encompassed (1) variations in mantle heat, rates of plate drift and of continental crustal growth, the gravitational effects of the Moon, and in rates of weathering, erosion, transport, deposition and diagenesis; (2) a decreasing planetary rotation rate over time; (3) no vegetation in the Precambrian, but prolific microbial mats, with the opposite pertaining to the Phanerozoic; (4) the long-term evolution of the hydrosphere-atmosphere-biosphere system. A relatively abrupt and sharp turning point was reached in the Neoarchaean, with spikes in mantle plume flux and tectonothermal activity and possibly concomitant onset of the supercontinent cycle. Substantial and irreversible change occurred subsequently in the Palaeoproterozoic, whereby the dramatic change from reducing to oxidizing volcanic gases ushered in change to an oxic environment, to be followed at ca. 2.4-2.3. Ga by the "Great Oxidation Event" (GOE); rise in atmospheric oxygen was accompanied by expansion of oxygenic photosynthesis in the cyanobacteria. A possible global tectono-thermal "slowdown" from ca. 2.45-2.2. Ga may have separated a preceding plate regime which interacted with a higher energy mantle from a ca. 2.2-2.0. Ga Phanerozoic-style plate tectonic regime; the "slowdown" period also encompassed the first known global-scale glaciation and overlapped with the GOE. While large palaeodeserts emerged from ca. 2.0-1.8. Ga, possibly associated with the evolution of the supercontinent cycle, widespread euxinia by ca. 1.85. Ga ushered in the "boring billion" year period. A second time of significant and irreversible change, in the Neoproterozoic, saw a second major oxidation event and several low palaeolatitude Cryogenian (740-630. Ma) glaciations. With the veracity of the "Snowball Earth" model for Neoproterozoic glaciation being under dispute, genesis of Pre-Ediacaran low-palaeolatitude glaciation remains enigmatic. Ediacaran (635-542. Ma) glaciation with a wide palaeolatitudinal range contrasts with the circum-polar nature of Phanerozoic glaciation. The observed change from low latitude to circum-polar glaciation parallels advent and diversification of the Metazoa and the Neoproterozoic oxygenation (ca. 580. Ma), and was succeeded by the Ediacaran-Cambrian transition which ushered in biomineralization, with all its implications for the chemical sedimentary record. © 2012 International Association for Gondwana Research.Patrick G. Eriksson, Santanu Banerjee, Octavian Catuneanu, Patricia L. Corcoran, Kenneth A. Eriksson, Eric E. Hiatt, Marc Laflamme, Nils Lenhardt, Darrel G.F. Long, Andrew D. Miall, Michael V. Mints, Peir K. Pufahl, Subir Sarkar, Edward L. Simpson, George E. William

Gap junctions and hemichannels: communicating cell death in neurodevelopment and disease

Gap junctions are unique membrane channels that play a significant role in intercellular communication in the developing and mature central nervous system (CNS). These channels are composed of connexin proteins that oligomerize into hexamers to form connexons or hemichannels. Many different connexins are expressed in the CNS, with some specificity with regard to the cell types in which distinct connexins are found, as well as the timepoints when they are expressed in the developing and mature CNS. Both the main neuronal Cx36 and glial Cx43 play critical roles in neurodevelopment. These connexins also mediate distinct aspects of the CNS response to pathological conditions. An imbalance in the expression, translation, trafficking and turnover of connexins, as well as mutations of connexins, can impact their function in the context of cell death in neurodevelopment and disease. With the ever-increasing understanding of connexins in the brain, therapeutic strategies could be developed to target these membrane channels in various neurological disorders