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[en] Highlights: • A water-based precipitation method for Sr-hydrogarnet is demonstrated. • Sr3Al2(OH)12 was obtained by a wet planetary ball milling without any mineralizer. • The formation mechanism can be explained by a dissolution-precipitation process. • Milder process conditions can minimize/avoid contamination from vessel and balls. • Water vapor affects the decomposition phases from Sr3Al2(OH)12.
[en] We report the results of a large-area study of water vapor along the Orion Molecular Cloud ridge, the purpose of which was to determine the depth-dependent distribution of gas-phase water in dense molecular clouds. We find that the water vapor measured toward 77 spatial positions along the face-on Orion ridge, excluding positions surrounding the outflow associated with BN/KL and IRc2, display integrated intensities that correlate strongly with known cloud surface tracers such as CN, C2H, 13CO J = 5-4, and HCN, and less well with the volume tracer N2H+. Moreover, at total column densities corresponding to AV< 15 mag, the ratio of H2O to C18O integrated intensities shows a clear rise approaching the cloud surface. We show that this behavior cannot be accounted for by either optical depth or excitation effects, but suggests that gas-phase water abundances fall at large AV. These results are important as they affect measures of the true water-vapor abundance in molecular clouds by highlighting the limitations of comparing measured water-vapor column densities with such traditional cloud tracers as 13CO or C18O. These results also support cloud models that incorporate freeze out of molecules as a critical component in determining the depth-dependent abundance of water vapor.
[en] This project plan gives a high-level description of the US Department of Energy Office of Nuclear Energy (DOE-NE) Spent Fuel and Waste Disposition (SFWD) campaign in situ borehole heater test project being planned for the Waste Isolation Pilot Plant (WIPP) site This plan provides an overview of the schedule and responsibilities of the parties involved. This project is a collaborative effort by Sandia, Los Alamos, and Lawrence Berkeley National Laboratories to execute a series of small-diameter borehole heater tests in salt for the DOE-NE SFWD campaign. Design of a heater test in salt at WIPP has evolved over several years. The current design was completed in fiscal year 2017 (FY17), an equipment shakedown experiment is underway in April FY18, and the test implementation will begin in summer of FY18. The project comprises a suite of modular tests, which consist of a group of nearby boreholes in the wall of drifts at WIPP. Each test is centered around a packer-isolated heated borehole (5' diameter) containing equipment for water-vapor collection and brine sampling, surrounded by smaller-diameter (2' diameter) satellite observation boreholes. Observation boreholes will contain temperature sensors, tracer release points, electrical resistivity tomography (ERT) sensors, fiber optic sensing, and acoustic emission (AE) measurements, and sonic velocity sources and sensors. These satellite boreholes will also be used for plugging/sealing tests. The first two tests to be implemented will have the packer-isolated borehole heated to 120°C, with one observation borehole used to monitor changes. Follow-on tests will be designed using information gathered from the first two tests, will be conducted at other temperatures, will use multiple observation boreholes, and may include other measurement types and test designs.
[en] Complete text of publication follows. Although many new details on the properties of mesospheric ice particles that form Polar Mesospheric Clouds (PMCs) and also cause polar mesospheric summer echoes have been recently revealed, certain aspects of mesospheric ice microphysics and dynamics still remain open. The detailed relation between PMC parameters and properties of their environment, as well as interseasonal and interhemispheric differences and trends in PMC properties that are possibly related to global change, are among those open questions. In this work, mesospheric temperature and water vapor concentration measured by the Sounding of the Atmosphere using Broadband Emission Radiometry (SABER) instrument on board the Thermosphere Ionosphere Mesosphere Energetics and Dynamics (TIMED) satellite are used to study the properties of PMCs with respect to the surrounding atmosphere. The cloud parameters, namely location, brightness, and altitude, are obtained from the observations made by the Optical Spectrograph and Infrared Imager System (OSIRIS) on the Odin satellite. About a thousand of simultaneous common volume measurements made by SABER and OSIRIS in both hemispheres from 2002 until 2008 are used. The correlation between PMC brightness (and occurrence rate) and temperatures at PMC altitudes and at the mesopause is analysed. The relation between PMC parameters, frost point temperature, and gaseous water vapor content in and below the cloud is also discussed. Interseasonal and interhemispheric differences and trends in the above parameters, as well as in PMC peak altitudes and mesopause altitudes are evaluated.
[en] Complete text of publication follows. The Aeronomy of Ice in the Mesosphere (AIM) mission was launched from Vandenberg Air Force Base in California at 1:26:03 PDT on April 25, 2007 becoming the first satellite mission dedicated to the study of noctilucent clouds. A Pegasus XL rocket launched the satellite into a near perfect 600 km, noon, sun synchronous circular orbit. AIM carries three instruments - a nadir imager, a solar occultation instrument and an in-situ cosmic dust detector. This paper will provide a brief mission overview, instrument descriptions and scientific findings. Results from the first two years of AIM observations show that the NLC season turns on and off like a 'geophysical light bulb' transitioning at the season start from no clouds to 100% occurrence frequency in days and vice versa at the season end. Data show that temperature change is a dominant factor in controlling season onset, variability during the season and season end. Rising water vapor levels at the beginning and falling values at the end also play a key role in season initiation and cessation. Structures seen in the clouds look very much like complex features seen in tropospheric clouds including large regions of near circular ice voids. This paper will also describe the first satellite observations of cosmic smoke input to the atmosphere measured by the SOFIE instrument. AIM is approved to operate through September 30, 2012.
[en] Atmospheric water vapor content was measured in two different regions in Brazil during the tests of a portable microwave receiver tuned at 22 GHz, the frequency of maximum emission of water vapor. The results are correlated with measurements made simultaneously at the 13.7 m radio-telescope from Radio Observatorio de Itapetinga, Atibaia, SP. (Author)
[pt]Foram realizadas medidas de conteudo de vapor de agua precipitavel na atmosfera em duas regioes distintas do Brasil, com o objetivo de testar um radiometro operando na frequencia de emissao do vapor de agua troposferico (22 GHz). O trabalho compara os resultados obtidos com medidas efetuadas simultaneamente com o radio-telescopio de 13,7 m, instalado no Radio Observatorio de Itapetinga, Atibaia, SP. (Autor)
[en] Complete text of publication follows. Using newly analysed mesospheric water vapor and temperature observations from the SMR microwave instrument aboard the Odin research satellite, we present evidence for an anomalously strong descent of dry mesospheric air from the lower mesosphere into the upper stratosphere in the late winter of 2004, and of 2006. In both cases, the descent follows the recovery of the upper stratospheric polar vortex from a mid-winter stratospheric sudden warming. It is also accompanied by the rapid formation of an anomalously warm polar mesospheric layer, i.e. an elevated stratopause, near 75km, and its slower descent to pre-warming level (near 1 hPa) over 1.5-2 months. These two winters stand out in the record of Odin/SMR observations spanning the period July 2001 to June 2008.