Decarboxylation of Carbon Compounds as a Potential Source for CO2 and CO Observed by SAM at Yellowknife Bay, Gale Crater, Mars

Martian carbon was detected in the Sheepbed mudtsone at Yellowknife Bay, Gale Crater, Mars by the Sample Analysis at Mars (SAM) instrument onboard Curiosity, the rover of the Mars Science Laboratory missio]. The carbon was detected as CO2 thermally evolved from drilled and sieved rock powder that was delivered to SAM as a <150-micron-particle- size fraction. Most of the CO2 observed in the Cumberland (CB) drill hole evolved between 150deg and 350deg C. In the John Klein (JK) drill hole, the CO2 evolved up to 500deg C. Hypotheses for the source of the the CO2 include the breakdown of carbonate minerals reacting with HCl released from oxychlorine compounds, combustion of organic matter by O2 thermally evolved from the same oxychlorine minerals, and the decarboxylation of organic molecules indigenous to the martian rock sample. Here we explore the potential for the decarboxylation hypothesis

X-Ray Diffraction and Reflectance Spectroscopy of Murchison Powders (CM2) After Thermal Analysis Under Reducing Conditions to Final Temperatures Between 300 and 1300c

The asteroids Ryugu and Bennu have spectral characteristics in common with CI/CM type carbonaceous chondrites and are target bodies for JAXAs Hayabusa2 and NASAs OSIRIS-Rex missions, respectively. Analog studies, based primarily on the Murchison CM2 chondrite, provide a pathway to separate spectral properties resulting space weathering from those inherent to parent-body, mineralogy, chemistry, and processes. Ryugu shares spectral properties with thermally metamorphosed and partly dehydrated CI/CM chondrites. We have undertaken a multidisciplinary study of the thermal decomposition of Murchison powder samples as an analog to metamorphic process that may have occurred on Ryugu. Bulk analyses include thermal And evolved gas analysis, X-ray diffraction (XRD), and VIS-NIR and Mssbauer spectroscopy; micro- to nanoscale analyses included scanning and transmission electron microscopy and electron probe micro analysisWe report here XRD and VIS-NIR analyses of pre- and post-heated Murchison powders, and in a companion paper report results from multiple electron beam techniques

Reaching Backward and Stretching Forward: Teaching for Transfer in Law School Clinics

In thinking about education, teachers may spend more time considering what to teach than how to teach. Unfortunately, traditional teaching techniques have limited effectiveness in their ability to help students retain and apply the knowledge either in later classes or in their professional work. What, then, is the value of our teaching efforts if students are unable to transfer the ideas and skills they have learned to later situations? Teaching for transfer is important to the authors of this article, four clinical professors and one psychologist. The purpose of this article is to provide an introduction to some of the techniques that can improve the transfer of teaching. While this article focuses on applications in the law clinic, the procedures can be profitably used in doctrinal classes as well. It is the goal of the authors of this article to help you improve your teaching so that your students will understand, remember, and be able to later use what you teach them. While this may appear overly ambitious, we are not selling snake oil. Rather, we are relying on established tenets of psychology and pedagogy that have proved successful in other areas of learning.In the first section, psychologist Shaun Archer will summarize the latest research results on memory and how to best teach so that students can retain and use information. Before transferring information or ideas from a class to a new situation, one must first anchor the concept in the mind. To do this, the student must attach the new information to the existing scaffolding in the student’s memory. Attached to the wrong structure, the new information cannot easily be used in a later application. For example, if you are told that both a successful asylum application and chlorophyll contain five elements, you might be momentarily chagrined since the word “elements” is used in two very different contexts. Your mind must travel down various discrete neural pathways to make correct sense of the use of the word in each phrase. This insight from psychology is the core of teaching for transfer. Tonya Kowalski will then introduce the principles of teaching for transfer, emphasizing “reaching backward” and “stretching forward” techniques. She will then suggest applications of these procedures in clinical teaching. In reaching backward, a student thinks back to past experiences or concepts to find existing mental scaffolding that can be used to bear the weight and provide an accessible resting place for the new material that is being taught. In stretching forward, a student consciously envisions potential future applications of the material being learned. Colleen Shanahan will demonstrate backward-reaching transfer techniques for teaching students skills and knowledge, using the examples of initial client interviews, soliciting facts from witnesses, researching eviction procedures, and developing an effective oral advocacy style. Jim Kelly will provide specific examples of stretching-forward transfer techniques. These range from “hugging,” identifying very similar future applications, such as the business record litany, to “bridging,” preparing students to be able to use new foundational skills or knowledge in complex and extremely varied situations

Reaching Backward and Stretching Forward: Teaching for Transfer in Law School Clinics

In thinking about education, teachers may spend more time considering what to teach than how to teach. Unfortunately, traditional teaching techniques have limited effectiveness in their ability to help students retain and apply the knowledge either in later classes or in their professional work. What, then, is the value of our teaching efforts if students are unable to transfer the ideas and skills they have learned to later situations? Teaching for transfer is important to the authors of this article, four clinical professors and one psychologist. The purpose of this article is to provide an introduction to some of the techniques that can improve the transfer of teaching\u27s lessons. While this article focuses on applications in the law clinic, the procedures can be profitably used in doctrinal classes as well

Can Silicon-Smelting Contribute to the Low O/Si Ratio on the Surface of Mercury?

The MErcury Surface, Space ENvironment, GEochemistry, and Ranging (MESSENGER) spacecraft collected data that provided important insights into the structure, chemical makeup, and compositional diversity of Mercury. Among the many discoveries about Mercury made by MESSENGER, several surprising compositional characteristics of the surface were observed. These discoveries include elevated sulfur abundances (up to 4 wt.%), elevated abundances of graphitic carbon (0-4.1 wt.% across the surface with an additional 1-3 wt.% graphite above the global average in low reflectance materials), low iron abundances (less than 2 wt.%), and low oxygen abundances (O/Si weight ratio of 1.20+/-0.1). These exotic characteristics likely have important implications for the thermochemical evolution of Mercury and point to a planet that formed under highly reducing conditions. In the present study, we focus specifically on the low O/Si ratio of Mercury, which is anomalous compared to all other planetary materials. A recent study that considered the geochemical implications of the low O/Si ratio reported that 12-20% of the surface materials on Mercury are composed of Si-rich, Si-Fe alloys. They further postulated that the origin of the metal is best explained by a combination of space weathering and graphite-induced smelting that was facilitated by interaction of graphite with boninitic and komatiitic parental liquids. The goal of the present study is to assess the plausibility of smelting on Mercury through experiments run at the conditions that McCubbin et al. indicated would be favorable for Si-smelting

An Exploration Zone in Cerberus Containing Young and Old Terrains, Including Fossae/Faults and Sher-Gottite Distal Ejecta

No abstract availabl

Influence of Oxychlorine Phases During the Pyrolysis of Organic Molecules: Implications for the Quest of Organics on Mars with the SAM Experiment Onboard the Curiosity Rover

One among the main objectives of the Sample Analysis at Mars (SAM) experiment is the in situ molecular analysis of gases evolving from solid samples heated up to approximately 850 degrees Centigrade, and collected by Curiosity on Mars surface/sub-surface in Gale crater. With this aim, SAM uses a gas-chromatograph coupled to a quadrupole mass spectrometer (GC-QMS) devoted to separate, detect and identify both volatile inorganic and organic compounds. SAM detected chlorinated organic molecules produced in evolved gas analysis (EGA) experiments. Several of these were also detected by the Viking experiments in 1976. SAM also detected oxychlorine compounds that were present at the Phoenix landing site. The oxychlorines may be prevelant over much of the martian surface. The C1 to C3 aliphatic chlorohydrocarbons (chloromethane and di- and trichloromethane) detected by SAM were attributed to reaction products occurring between the oxychlorines phases and the organic compounds coming from SAM instrument background. But SAM also showed the presence of a large excess of chlorobenzene and C2 to C4 dichloroalkanes among the volatile species released by the Cumberland sample of the Sheepbed mudstone. For the first time in the history of the Mars exploration, this proved the presence of Mars indigenous organic material at the Mars' surface. However, the identification of the precursor organic compounds of these chlorohydrocarbons is difficult due to the complexity of the reactions occurring during the sample pyrolysis. Laboratory pyrolysis experiments have demonstrated that oxychlorines phases such as perchlorates and chlorates, decomposed into dioxygen and volatile chlorine bearing molecules (HCl and/or Cl2) during the pyrolysis. These chemical species can then react with the organic molecules present in the martian solid samples through oxidation, chlorination and oxychlorination processes

Reactions Involving Calcium and Magnesium Sulfates as Potential Sources of Sulfur Dioxide During MSL SAM Evolved Gas Analyses

The Sample Analysis at Mars (SAM) and Chemistry and Mineralogy (CheMin) instruments on the Mars Science Laboratory (MSL) have analyzed several subsamples of 860 C). Sulfides or Fe sulfates were detected by CheMin (e.g., CB, MJ, BK) and could contribute to the high temperature SO2 evolution, but in most cases they are not present in enough abundance to account for all of the SO2. This additional SO2 could be largely associated with x-ray amorphous material, which comprises a significant portion of all samples. It can also be attributed to trace S phases present below the CheMin detection limit, or to reactions which lower the temperatures of SO2 evolution from sulfates that are typically expected to thermally decompose at temperatures outside the SAM temperature range (e.g., Ca and Mg sulfates). Here we discuss the results of SAM-like laboratory analyses targeted at understanding this last possibility, focused on understanding if reactions of HCl or an HCl evolving phase (oxychlorine phases, chlorides, etc.) and Ca and Mg sulfates can result in SO2 evolution in the SAM temperature range