Properties of LiF and Al_2O_3 to 240 GPa for Metal Shock Temperature Measurements

Shock temperature experiments employing a six-channel pyrometer were conducted on 200, 500, and 1000 A thick films of Fe sandwiched between 3-mm-thick anvils of Al203 and LiF to measure the thermal diffusivity ratios Al_20_3/Fe and LiF / Fe at high temperatures and pressures. Temperature decays of 3000 ± 800 K in 250 ns were observed at Fe pressures of 194 - 303 GPa, which reflect the conduction of heat from the thin metal films into the anvil material. These results were achieved via experiments employing LiF anvils at conditions of 164 - 165 GPa and 4190 - 4220 K and Al_2O_3 anvils at conditions of 156 - 304 GPa and 1290 - 2740 K. Thermal modeling of interface temperature versus time yields best fit thermal diffusivity ratios of 4 - 19 ± 1 (Fe/anvil) over the pressure and temperature range of the experiments. Calculated thermal conductivities for Fe, using electron gas theory, of 111 - 181 W /mK are used to calculate thermal conductivities for the anvil materials ranging from 2 to 13 W /mK. Debye theory predicts higher values of 8 to 35 W /mK. Data from previous experiments on thick (≥l00μm) films of Fe and stainless steel are combined with our present results from experiments on thin (≤1000 A) films to infer a 5860 ± 390 K Hugoniot temperature for the onset of melting of iron at 243 GPa. Our results address the question of whether radiation observed in shock temperature experiments on metals originates from the metal at the metal/anvil interface or from the shocked anvil. We conclude that the photon flux from the shocked assemblies recorded in all experiments originates from the metal. Within the uncertainties of the shock temperature data, the uncertainties in shock temperatures resulting from the radiation from the anvils is negligible. This is in direct disagreement with the conclusions of previous work by Kondo

Accounting for Exchange Transactions: An Alternative Perspective

This paper presents a simple alternative method of recording exchange transactions that is theoretically superior to the popular gross method and is more informative than either the net or gross method

A Model for Hospital Discharge Preparation: From Case Management to Care Transition

There has been a proliferation of initiatives to improve discharge processes and outcomes for the transition from hospital to home and community-based care. Operationalization of these processes has varied widely as hospitals have customized discharge care into innovative roles and functions. This article presents a model for conceptualizing the components of hospital discharge preparation to ensure attention to the full range of processes needed for a comprehensive strategy for hospital discharge

Phase Changes and Transport Properties of Geophysical Materials Under Shock Loading

The lower mantle of the Earth is believed to be largely composed of (Mg, Fe)O (magnesiowiistite) and (Mg,Fe)SiO₃ (perovskite); thus the high pressure phase of (Mg,Fe)₂SiO₄ (olivine), which is believed to be perovskite plus magnesiowiistite is of geophysical interest. Radiative temperatures of single-crystal olivine starting material [(Mg_(0.9), Fe_(0.1))₂SiO₄] decreased abruptly from 7040 ± 315 to 4300 ± 270 K upon shock compression above 80 GPa. The data indicate that an upper bound to the solidus of the magnesiowiistite and perovskite assemblage at 4300 ± 270 K is 130 ± 3 GPa. These conditions correspond to those for partial melting at the base of the mantle, as has been suggested to occur within the recently discovered ultra-low-velocity zone (ULVZ) beneath the Central Pacific. We construct speculative high pressure phase diagrams for the MgO - SiO₂ system using experimental data from our work, and other mineral physics experiments. In separate experiments, time dependent shock temperatures were measured for stainless steel (SS) films sandwiched between two transparent Al₂O₃ anvils. The anvil material was the same as the driver material so that there would be symmetric heat flow from the sample. Inferred Hugoniot temperatures, T_h, of 5000 - 8500±500 Kat 222- 321 GPa are consistent with previous measurements in SS. Temperatures at the film­ anvil interface (T_i), which are directly measured (rather than T_h) indicate that T_i did not decrease measurably during the approximately 250 ns that the shock wave took to traverse the Al₂O₃ anvil. Thus an upper bound is obtained for the thermal diffusivity of Al₂O₃ at the metal/anvil interface of K ≤ 14 ± 5 cm²/s at 208 GPa and 2110 K. This is a factor of 1.6 lower than previously calculated values, resulting in a decrease of the inferred T_h by at least 400 K. The observed shock temperatures are combined with temperatures calculated from measured Hugoniots and are used to calculate the thermal conductivity of Al₂O₃. There was no measurable radiant-intensity decrease during the time when the shock wave propagated through the anvil; we infer from this that Al₂O₃ remained transparent while in the shocked state. Thus an Al₂O₃ anvil is sufficiently transparent for shock temperature measurements for metals, to at least 240 GPa. Finally, shock temperature experiments employing a six-channel pyrometer were conducted on 200, 500, and 1000 Å thick films of Fe sandwiched between 3 mm thick anvils of Al₂O₃ and LiF, to measure the thermal diffusivity ratios of Al₂O₃/Fe and LiF/Fe, at high temperatures and pressures. Temperature decays of 3000 ± 800 K in 250 ns were observed at Fe pressures of 194 - 303 GPa, which reflect the conduction of heat from the thin metal films into the anvil material. These results were achieved in experiments employing LiF anvils at 164 - 166 GPa and 4190 - 4220 K, and Al2O3 anvils at 196 - 303 GPa and 1410 - 2750 K. Thermal modeling of interface temperature versus time yields best fit thermal diffusivity ratios ranging from 15 ± 30 to 80 ± 20 (Fe/anvil) over the pressure and temperature range of the experiments. Calculated thermal conductivities for Fe, using electron gas theory, of 110 - 212 W /mK are used to calculate thermal conductivities for the anvil materials ranging from 6 to 12 W/mK. Debye theory predicts higher values of 8 to 34 W/mK. Data from previous experiments on thick (≥ 100µm) films of Fe and stainless steel are combined with our present results from experiments on thin (≤ 1000 Å) films to infer a 5860 ± 390 K Hugoniot temperature for the onset of melting of iron at 243 GPa. Our results address the question of whether radiation observed in shock temperature experiments on metals originates from the metal at the metal/ anvil interface or from the shocked anvil. We conclude that the photon flux from the shocked iron/anvil sandwich recorded in all experiments originates from the metal. Within the uncertainties of the shock temperature data, the uncertainties in shock temperatures resulting from the radiation from the anvils is negligible. This is in direct disagreement with previous conclusions of Kondo.</p

Phase diagram of iron, revised-core temperatures

Shock-wave experiments on iron preheated to 1573 K from 14 to 73 GPa, yield sound velocities of the γ- and liquid-phases. Melting is observed in the highest pressure (∼71 ± 2 GPa) experiments at calculated shock temperatures of 2775 ± 160 K. This single crossing of the γ-liquid boundary agrees with the γ-iron melting line of Boehler [1993], Saxena et al. [1993], and Jephcoat and Besedin [1997]. This γ-iron melting curve is ∼300°C lower than that of Shen et al. [1998] at 80 GPa. In agreement with Brown [2001] the discrepancy between the diamond cell melting data and the iron shock temperatures require the occurrence of yet another sub-solidus phase along the principal Hugoniot at ∼200 GPa. This would reconcile the static and dynamic data for iron's melting curve. Upward pressure and temperature extrapolation of the γ-iron melting curve to 330 GPa yields 5300 ± 400 K for the inner core-outer core boundary temperature

Shock temperatures and the melting point of iron

New measurements of the ratio of Fe to LiF and Al_2O_3 anvil thermal diffusivities are used to obtain revised shock temperatures for Fe. New results match Brown and McQueen’s (1) calculations of the temperatures of 5000 and 5800K at the 200 and 243 GPa transitions in Fe. New sound speed measurements along the Hugoniot of γ-Fe, centered at 1573K, demonstrate that this phase melts at ∼70 GPa and ∼2800 K and the γ phase does not occur above ∼93 GPa. At higher pressures, perhaps over the entire pressure range of the Earth’s molten outer core (132 to 330 GPa), the β (dhcp) phase, and not the ε phase, appears to be the solidus phase of pure Fe

Human Inborn Errors of Immunity: 2019 Update on the Classification from the International Union of Immunological Societies Expert Committee.

We report the updated classification of Inborn Errors of Immunity/Primary Immunodeficiencies, compiled by the International Union of Immunological Societies Expert Committee. This report documents the key clinical and laboratory features of 430 inborn errors of immunity, including 64 gene defects that have either been discovered in the past 2 years since the previous update (published January 2018) or were characterized earlier but have since been confirmed or expanded upon in subsequent studies. The application of next-generation sequencing continues to expedite the rapid identification of novel gene defects, rare or common; broaden the immunological and clinical phenotypes of conditions arising from known gene defects and even known variants; and implement gene-specific therapies. These advances are contributing to greater understanding of the molecular, cellular, and immunological mechanisms of disease, thereby enhancing immunological knowledge while improving the management of patients and their families. This report serves as a valuable resource for the molecular diagnosis of individuals with heritable immunological disorders and also for the scientific dissection of cellular and molecular mechanisms underlying inborn errors of immunity and related human diseases

Human Inborn Errors of Immunity: 2019 Update of the IUIS Phenotypical Classification.

Since 2013, the International Union of Immunological Societies (IUIS) expert committee (EC) on Inborn Errors of Immunity (IEI) has published an updated phenotypic classification of IEI, which accompanies and complements their genotypic classification into ten tables. This phenotypic classification is user-friendly and serves as a resource for clinicians at the bedside. There are now 430 single-gene IEI underlying phenotypes as diverse as infection, malignancy, allergy, autoimmunity, and autoinflammation. We herein report the 2019 phenotypic classification, including the 65 new conditions. The diagnostic algorithms are based on clinical and laboratory phenotypes for each of the ten broad categories of IEI

Microbial rRNA sequencing analysis of evaporative cooler indoor environments located in the Great Basin Desert region of the United States

Recent studies conducted in the Great Basin Desert region of the United States have shown that skin test reactivity to fungal and dust mite allergens are increased in children with asthma or allergy living in homes with evaporative coolers (EC). The objective of this study was to determine if the increased humidity previously reported in EC homes leads to varying microbial populations compared to homes with air conditioners (AC). Children with physician-diagnosed allergic rhinitis living in EC or AC environments were recruited into the study. Air samples were collected from the child's bedroom for genomic DNA extraction and metagenomic analysis of bacteria and fungi using the Illumina MiSeq sequencing platform. The analysis of bacterial populations revealed no major differences between EC and AC sampling environments. The fungal populations observed in EC homes differed from AC homes. The most prevalent species discovered in AC environments belonged to the genera Cryptococcus (20%) and Aspergillus (20%). In contrast, the most common fungi identified in EC homes belonged to the order Pleosporales and included Alternaria alternata (32%) and Phoma spp. (22%). The variations in fungal populations provide preliminary evidence of the microbial burden children may be exposed to within EC environments in this region