Development of a Reactor Model for Chemical Conversion of Lunar Regolith

Lunar regolith will be used for a variety of purposes such as oxygen and propellant production and manufacture of various materials. The design and development of chemical conversion reactors for processing lunar regolith will require an understanding of the coupling among the chemical, mass and energy transport processes occurring at the length and time scales of the overall reactor with those occurring at the corresponding scales of the regolith particles. To this end, a coupled transport model is developed using, as an example, the reduction of ilmenite-containing regolith by a continuous flow of hydrogen in a flow-through reactor. The ilmenite conversion occurs on the surface and within the regolith particles. As the ilmenite reduction proceeds, the hydrogen in the reactor is consumed, and this, in turn, affects the conversion rate of the ilmenite in the particles. Several important quantities are identified as a result of the analysis. Reactor scale parameters include the void fraction (i.e., the fraction of the reactor volume not occupied by the regolith particles) and the residence time of hydrogen in the reactor. Particle scale quantities include the time for hydrogen to diffuse into the pores of the regolith particles and the chemical reaction time. The paper investigates the relationships between these quantities and their impact on the regolith conversion. Application of the model to various chemical reactor types, such as fluidized-bed, packed-bed, and rotary-bed configurations, are discussed

A mathematical model to characterize effect of silica content in the boiler fly ash on erosion behaviour of boiler grade steel

Fly ash particles entrained in the flue gas of coal-fired boilers can cause serious erosion on the critical components along the flow path. Such erosion can significantly jeopardise operational life of the boiler. A first principle based theoretical model has been developed embodying the mechanisms of erosion involving cuttingwear, plastic deformationwear and effect of temperature on erosion behaviour, to predict erosion rates of pertinent boiler grade steels. Various grades of steels commonly used in the fabrication of boiler components and published data pertaining to boiler fly ash has been used in modelling the phenomena. The model also provides a quantitative predictive framework to study the effect of percentage of silica content in the ash particles on the erosion potential. The erosion sensitivity of particle impact velocity, angle of impingement and variation of surface temperature of the substrate (steel) have also been studied as a function of silica content in the ash. The model has been implemented in a computer code to predict the erosion rates at room and elevated temperature for various grades of steels under different particle impact conditions. The model predictions have been found to be in good agreement with the published data. This investigation illustrated that any minor increase in silica level in the ash can considerably aggravate the erosion rates, signifying the fact that silica content in the ash plays a critical role in characterising erosion potential of fly ash

Results of the 2016 Indianapolis Biodiversity Survey, Marion County, Indiana

Surprising biodiversity can be found in cities, but urban habitats are understudied. We report on a bioblitz conducted primarily within a 24-hr period on September 16 and 17, 2016 in Indianapolis, Indiana, USA. The event focused on stretches of three waterways and their associated riparian habitat: Fall Creek (20.6 ha; 51 acres), Pleasant Run (23.5 ha; 58 acres), and Pogue’s Run (27.1 ha; 67 acres). Over 75 scientists, naturalists, students, and citizen volunteers comprised 14 different taxonomic teams. Five hundred ninety taxa were documented despite the rainy conditions. A brief summary of the methods and findings are presented here. Detailed maps of survey locations and inventory results are available on the Indiana Academy of Science website (https://www.indianaacademyofscience.org/)

Degradation of MEPE, DMP1, and Release of SIBLING ASARM-Peptides (Minhibins): ASARM-Peptide(s) Are Directly Responsible for Defective Mineralization in HYP

Mutations in PHEX (phosphate-regulating gene with homologies to endopeptidases on the X chromosome) and DMP1 (dentin matrix protein 1) result in X-linked hypophosphatemic rickets (HYP) and autosomal-recessive hypophosphatemic-rickets (ARHR), respectively. Specific binding of PHEX to matrix extracellular phosphoglycoprotein (MEPE) regulates the release of small protease-resistant MEPE peptides [acidic serine- and aspartate-rich MEPE-associated motif (ASARM) peptides]. ASARM peptides are potent inhibitors of mineralization (minhibins) that also occur in DMP1 [MEPE-related small integrin-binding ligand, N-linked glycoprotein (SIBLING) protein]. It is not known whether these peptides are directly responsible for the mineralization defect. We therefore used a bone marrow stromal cell (BMSC) coculture model, ASARM peptides, anti-ASARM antibodies, and a small synthetic PHEX peptide (SPR4; 4.2 kDa) to examine this. Surface plasmon resonance (SPR) and two-dimensional 1H/15N nuclear magnetic resonance demonstrated specific binding of SPR4 peptide to ASARM peptide. When cultured individually for 21 d, HYP BMSCs displayed reduced mineralization compared with wild type (WT) (−87%, P < 0.05). When cocultured, both HYP and WT cells failed to mineralize. However, cocultures (HYP and WT) or monocultures of HYP BMSCs treated with SPR4 peptide or anti-ASARM neutralizing antibodies mineralized normally. WT BMSCs treated with ASARM peptide also failed to mineralize properly without SPR4 peptide or anti-ASARM neutralizing antibodies. ASARM peptide treatment decreased PHEX mRNA and protein (−80%, P < 0.05) and SPR4 peptide cotreatment reversed this by binding ASARM peptide. SPR4 peptide also reversed ASARM peptide-mediated changes in expression of key osteoclast and osteoblast differentiation genes. Western blots of HYP calvariae and BMSCs revealed massive degradation of both MEPE and DMP1 protein compared with the WT. We conclude that degradation of MEPE and DMP-1 and release of ASARM peptides are chiefly responsible for the HYP mineralization defect and changes in osteoblast-osteoclast differentiation.We acknowledge the very kind gift of pure sPHEX by Dr. Philippe Crine (Department of Biochemistry, University of Montreal, and Enobia Pharma). Also, we acknowledge the anti-DMP1 antibodies generously donated by Dr. Larry Fisher, National Institute of Dental and Craniofacial Research, Bethesda, MD. Address all correspondence and requests for reprints to: Peter S. N. Rowe, Department of Internal Medicine, Division of Nephrology and Hypertension, The Kidney Institute, MS 3018, 3901 Rainbow Boulevard, Kansas City, Kansas 66160. E-mail: [email protected]. We acknowledge the generous financial support from the National Institutes of Health to P.S.N.R. (RO-1 AR51598-01; National Institute of Arthritis and Musculoskeletal Diseases). Also, the SPR experiments were performed in the UTHSCSA Center for Macromolecular Interactions, which is supported by grants from the National Cancer Institute (CA54174) and UTHSCSA Executive Research Committee Research fund

Evaluation of antigens for the serodiagnosis of kala-azar and oriental sores by means of the indirect immunofluorescence antibody test (IFAT)

Antigens and corresponding sera were collected from travellers with leishmaniasis returning to Germany from different endemic areas of the old world. The antigenicity of these Leishmania strains, which were maintained in Syrian hamsters, was compared by indirect immunofluorescence (IFAT). Antigenicity was demonstrated by antibody titres in 18 sera from 11 patients. The amastigotic stages of nine strains of Leishmania donovani and four strains of Leishmania tropica were compared with each other and with the culture forms of insect flagellates (Strigomonas oncopelti and Leptomonas ctenocephali). Eighteen sera from 11 patients were available for antibody determination with these antigens. The maximal antibody titres in a single serum varied considerably depending on which antigen was used for the test. High antibody levels could only be maintained when Leishmania donovani was employed as the antigen, but considerable differences also occurred between the different strains of this species. The other antigens were weaker. No differences in antigenicity between amastigotes and promastigotes of the same strain were observed. It is important to select suitable antigens. Low titres may be of doubtful specificity and are a poor baseline for the fall in titre which is an essential index of effective treatment.Wir sammelten Parasiten und Seren von Reisenden, die aus verschiedenen endemischen Gebieten der Alten Welt mit einer Leishmaniasis nach Deutschland zurückkehrten. Die Antigenaktivitäten der isolierten und fortlaufend in Goldhamstern gehaltenenLeishmania-Stämme wurden im indirekten Immunofluoreszenztest (IFAT) verglichen. Die Antigenität wurde an Hand von Antikörpertitern in 18 Serumproben von 11 Patienten bewiesen. Neun Stämme desLeishmania donovani-Komplexes und vierLeishmania tropica-Isolate wurden in ihrem amastigoten Stadium miteinander verglichen. Hinzu kamen zwei Insekten-Flagellaten als Kulturformen:Strigomonas oncopelti undLeptomonas ctenocephali. 18 Serumproben von 11 Patienten standen für die Antikörperbestimmung mit diesen Antigenen zur Verfügung. Die maximalen Titerhöhen variierten in ein- und derselben antiserumprobe zum Teil erheblich, je nachdem, welches Antigen für den Test benutzt wurde. Hohe Antikörpertiter konnten nur erhalten werden, wennLeishmania donovani als Antigen vorlag, es ergaben sich aber auch zwischen den einzelnen Stämmen dieser Leishmaniaart erhebliche Unterschiede in der Antigenaktivität. Antigene anderer Art erwiesen sich als wenig wirksam. Zwischen amastigoten und promastigoten Entwicklungsformen einesLeishmania donovani-Stammes konnten keine Unterschiede in der Antigenaktivität erkannt werden. Für den Nachweis möglichst hoher Antikörpertiter im IFAT ist die Auswahl geeigneter Antigene von ausschlaggebender Bedeutung. Niedrige Titer erschweren deren Beurteilung als spezifisch und sind eine schlechte Ausgangsposition für die Beobachtung des obligatorischen Titerabfalles nach erfolgreicher Therapie

Accounting for test reliability in student progression: the reliable change index

Context Developed by Jacobson and Truax, the reliable change index (RCI) provides a measure of whether the change in an individual's score over time is within or beyond that which might be accounted for by measurement variability. In combination with measures of whether an individual's final score is closer to those of one population or another, this provides useful individual-level information that can be used to supplement traditional analyses. Objectives This article aims to highlight the potential of the RCI for use within medical education, particularly as a novel means of monitoring progress at the student level across successive test occasions or academic years. Methods We provide an example of how the RCI can be applied informatively to assessment evaluation, and discuss its wider usage. Conclusions The RCI approach can be used to identify and support failing students, as well as to determine best teaching and learning practices by identifying high-performing students. Furthermore, the individual-level nature of the RCI makes it well suited for educational research with small cohorts, as well as for tracking individual profiles within a larger cohort or addressing questions about individual performance that may be unanswerable at group level

Investigation of slowing down and charge-exchange of nickel and uranium ions in gases and solids in the energy range (60 - 200) MeV/u

In this thesis new slowing down and charge-state measurements will be presented in the energy range of (60 - 200) MeV/u. These measurements were done using the Fragment Separator (FRS) facility at GSI in Darmstadt. The presented data were taken during two experimental runs. The experiments were divided into two parts. In the first part a 200 MeV/u Ni27+ beam was used. The evolution of charge states as a function of the target thickness was investigated covering both the non-equilibrium and equilibrium region. This was done with various mono-atomic materials (Z2 = 6, 7, 10, 13, 18, 22) and compound materials (ethylene, polyethylene and polypropylene). From the measured charge-state distributions the one-electron ionization and capture cross sections have been extracted. A 40 % gas-solid difference is observed in the ionization cross sections for the mono-atomic materials. In the compound materials a 30 % difference is observed between ethylene and the polymers. The experimental cross sections for the mono-atomic materials have been compared with theoretical calculations [1, 2]. The theoretical ionization cross sections agree quite well with the corresponding experimental ionization cross sections. In the gaseous targets the agreement between experiment and theory is better than 3 %. For the capture cross sections the agreement between experiment and theory is also very good for the lighter target materials (Z2 <= 7). For the heavier targets large deviations up to one order of magnitude are observed. These deviations are due to the increasing importance of the non-radiative capture channel in heavier target materials which is quite difficult to calculate accurately. The results motivate for further refinement of the theory in this energy region. In the second part 3 different uranium beams were used with initial energies of 61 MeV/u (U86+ incident), 85 MeV/u (U73+ incoming) and 200 MeV/u (U81+ incident) to measure the evolution of the charge states again and the energy loss as a function of the target thickness in the same materials as used in the first part plus some additional mono-atomic materials Z2 = 29, 36, 47, 54. From the measured charge-state distributions and energy losses the mean charges and stopping forces have been extracted. At 61 MeV/u we observe a gas-solid difference in the mean charge of up to 4 charge states for the mono-atomic materials. The corresponding stopping powers (forces) at the same specific energy only show a gas-solid difference for light materials (Z2 <= 7). The stopping forces are compared with calculations done with the PASS code [3, 4], ATIMA code [5] and the Hubert et al. tables [6]. The agreement is quite good between experiment and theory. The PASS code predicts by using the experimental mean charges a gas-solid difference in the stopping force for the heavier target materials. In the data at 200 MeV/u there is a gas-solid difference in the ionization rate for U81+ ions similar to the Ni27+ results.In dieser Dissertation werden neue Ladungsverteilungen und Energieverlustmessungen präsentiert. Diese Messungen wurden am Fragment Separator (FRS) bei der GSI in Darmstadt durchgeführt. Die Daten, die hier vorgestellt werden, wurden in zwei Experimenten aufgenommen. Die Experimente bestanden aus zwei Teilen. Im ersten Teil wurde mit einem 200 MeV/u Ni27+ Strahl gemessen. Ziel dieser Messung war die Entwicklung der Ladungsverteilung als Funktion der Targetdicke vom Nichtgleichgewicht bis Gleichgewicht zu untersuchen. Dies wurde mit verschiedenen Targets gemacht (Z2 = 6, 7, 10, 13, 18, 22, Äthylen, Polyäthylen und Polypropylen). Von den gemessenen Ladungsverteilung konnten die Umladungsquerrschnitte für Elektroneneinfang und -verlust extrahiert werden. Ein Gas-Festkörper Effekt von 40 % wurde im Ionizationsquerrschnitt für die monoatomaren (reinen Elemente) Targets gemessen. Im Äthylen und den Polymeren (Polyäthylen und Polypropylen) war ein Effekt von 30 % zu sehen. Die experimentellen Umladungsquerrschnitte für die monoatomaren Targets wurden mit theoretischen Rechnungen von A. Surzhykov und S. Fritzsche [1] und V. P. Shevelko [2] verglichen. In der Ionization stimmen die theoretischen Rechnungen mit den experimentellen Werten gut überein. In den Gastargets ist die Übereinstimmung besser als 3 %. Im Elektroneneinfang gibt es gute Übereinstimmung zwischen Experiment und Theorie bei den leichten Targets (Z2 <= 7), bei den schweren Targets gibt es grosse Abweichungen bis zu einer Grössenordnung. Diese Abweichung kommt zustande, weil der nicht-radiative Querrschnitt einen grösseren Anteil hat bei den schweren Targets und dieser Teil sehr schwer theoretisch zu rechnen ist. Die Ergebnisse sind eine Motivation für Verbesserungen in der Theorie im diesen Energiebereich. Im zweiten Teil wurde ein Uranstrahl bei drei verschiedenen Energien benutzt, diese waren 61 MeV/u mit 86+ als Eingangsladungszustand, 85 MeV/u mit 73+ als Eingangsladungszustand und 200 MeV/u mit 81+ als Eingangsladungszustand. Ziel dieser Messung war es wiederum, die Entwicklung der Ladungsverteilung zu untersuchen und auch Energieverluste zu messen. Dieselben Targets wurden benutzt und zusätzlich wurden folgende Targets vermessen Z2 = 29, 36, 47, 54. Von den gemessenen Ladungsverteilungen und Energieverlusten wurde die mittlere Ladung und das Bremsvermögen bestimmt. Bei 61 MeV/u ist ein Gas-Festkörper Effekt in der mittleren Ladung bei den monoatomaren Targets zu sehen. Der Effekt hat eine Grösse von fast 4 Ladungen. Das dazu gehörige Bremsvermögen zeigt nur einen Gas-Festkörper Effekt bei den leichteren Targets (Z2 <= 7). Die experimentellen Werte wurden mit dem PASS Programm [3, 4], dem ATIMA Programm [5] und den Hubert et al. Tabellen [6] verglichen. Die theoretischen Rechnungen von den Programmen stimmen mit den experimentellen Werten gut überein. PASS sagt einen Gas-Festkörper Effekt bei den schwereren Targets voraus, weil experimentelle Ladungen als Eingangsparameter benutzt wurden. Bei der 200 MeV/u Messung wurde ein Gas-Festkörper Unterschied in der Ionizationsrate in der Entwicklung des U81+ Ladungszustand beobachtet, ähnlich wie in der Ni27+ Messung

Low and variable correlation between reaction time costs and accuracy costs explained by accumulation models: Meta-analysis and simulations.

The underpinning assumption of much research on cognitive individual differences (or group differences) is that task performance indexes cognitive ability in that domain. In many tasks performance is measured by differences (costs) between conditions, which are widely assumed to index a psychological process of interest rather than extraneous factors such as speed–accuracy trade-offs (e.g., Stroop, implicit association task, lexical decision, antisaccade, Simon, Navon, flanker, and task switching). Relatedly, reaction time (RT) costs or error costs are interpreted similarly and used interchangeably in the literature. All of this assumes a strong correlation between RT-costs and error-costs from the same psychological effect. We conducted a meta-analysis to test this, with 114 effects across a range of well-known tasks. Counterintuitively, we found a general pattern of weak, and often no, association between RT and error costs (mean r = .17, range −.45 to .78). This general problem is accounted for by the theoretical framework of evidence accumulation models, which capture individual differences in (at least) 2 distinct ways. Differences affecting accumulation rate produce positive correlation. But this is cancelled out if individuals also differ in response threshold, which produces negative correlations. In the models, subtractions between conditions do not isolate processing costs from caution. To demonstrate the explanatory power of synthesizing the traditional subtraction method within a broader decision model framework, we confirm 2 predictions with new data. Thus, using error costs or RT costs is more than a pragmatic choice; the decision carries theoretical consequence that can be understood through the accumulation model framework