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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
491

Diffusion-controlled phase transitions as a tool for tailoring Fe-Ga functional properties

Palacheva, V.V., Emdadi, A., Emeis, F., Bobrikov, I.A., Divinski, S.V., Balagurov, A.M., Wilde, G., Golovin, I.S. 17 September 2018 (has links)
No description available.
492

Vida de fe en familia en estudiantes de una institución educativa del distrito de Santa Rosa 2016

Rafael Perez, Neire, Diaz Delgado, Marino January 2018 (has links)
El presente trabajo de investigación tiene como determinar las características de la vivencia de la fe en familia según dimensiones, en estudiantes de la I.E. José Olaya Balandra del distrito de Santa Rosa en el año 2016. Esta investigación se ha realizado con un enfoque cuantitativo, perteneciendo a un tipo de investigación descriptivo, puesto que solo se ha pretendido conocer la realidad en torno a la vida de fe en familia de los estudiantes encuestados. Se trabajó con una muestra de 578 estudiantes a quienes se aplicó un diagnóstico (cuestionario). Los resultados de la investigación se puede resumir en que la mayoría de familias no viven su fe de manera activa, especialmente en lo que se refiere a prácticas relacionadas con los sacramentos o devociones relacionadas con la Virgen María y los santos.
493

Vivencias de fe ante la eucaristía en los confirmandos de la I.E. “Luis Alberto Sánchez”, La Zaranda, Pítipo, 2016

Arrasco Gelacio, Maritza Cecilia, Gonzales Vasquez, Bertha January 2018 (has links)
La presente investigación realizada en la I.E. "Luis Alberto Sánchez”, la Zaranda, Pítipo-2016, responde a diversas problemáticas existentes en el área de educación religiosa, la más resaltante, se sitúa en torno a las vivencias de fe ante la Eucaristía que tienen los estudiantes, pues muchas veces no se le da la debida importancia. Ante esto, la investigación tuvo como objetivo general: Determinar las vivencias de fe ante la eucaristía en los confirmados de la I.E estudiada, por lo cual nos planteamos: ¿De qué manera los jóvenes confirmandos vivencian su fe ante la eucaristía en la I.E Luis Alberto Sánchez- La Zaranda- Pítipo 2016? El enfoque de la investigación es cuantitativo, de tipo descriptivo, con muestra no aleatoria. Como instrumento de recolección de datos se utilizó una encuesta. Se concluyó que los estudiantes presentan diversas deficiencias en torno a los actos de piedad y de fe, y que sólo el 50% se encuentran en un nivel idóneo de la escala. A su vez, los estudiantes muestran más fortalezas en los actos de fe que en los de piedad, manifestando paulatinamente un desarrollo constante.
494

Aula virtual para desarrollar la competencia : investiga y profundiza los fundamentos de la fe cristiana relacionada a la cultura

Purisaca Vigil, Fidel January 2019 (has links)
El presente estudio buscó determinar la influencia del uso del aula virtual en el nivel de desarrollo de la competencia: investiga y profundiza los fundamentos de la fe cristiana y relación existente con la cultura, en el curso de Fe y Cultura, en los estudiantes del V Ciclo de la Universidad Católica Santo Toribio de Mogrovejo, durante el año 2016 - I. Para ello, se trabajó con un enfoque cuantitativo, y diseño pre-experimental. La población lo conformaron 333 universitarios de diferentes carreras profesionales del V Ciclo que cursaron la asignatura Fe y Cultura en el año 2016; de los cuales, se seleccionó a 42 estudiantes para que sean parte de la muestra de estudio, cuya validez estadística se calculó mediante el valor del coeficiente de fiabilidad Alfa de Cronbach. En esta investigación se llegó a concluir que existe una influencia significativa acerca del uso del aula virtual sobre el nivel de desarrollo de la competencia: investiga y profundiza los fundamentos de la fe cristiana y relación existente con la cultura (valor de Z = - 5,805 y p = 0,000) en el curso de Fe y Cultura, en los estudiantes del V Ciclo de la USAT, durante el 2016 - I.
495

Timber Shear Wall Analysis : Parameterized Finite Element Modelling

Kormendy, Imre, Muwaili, Mustafa January 2018 (has links)
This paper investigates the linear elastic behavior of timber shear walls under monotonic prescribed displacement. ABAQUS© 16.4-5, is a numerical finite element software used as the primary analysis methodology.  Parameterized models are created for two shear wall specimens of different geometry concerning door and window configurations. The shear walls are simulated as solid timber framing which is mechanically connected to gypsum sheathing board through fasteners. The primary findings are the linear elastic shear force distribution of the mechanical joints. Additionally, deformations and reaction forces of the shear walls are determined. The overall horizontal shear wall behavior of each specific wall was also studied in the presence of door and window openings. The simulations indicate there is a clear deformation difference in the behaviors of the two shear walls. Furthermore, the highest shear force values of the fasteners are located around the corners of the openings. The findings are supported by other researcher’s experiments and analytical tests, timber shear wall theory and Eurocode design requirements.
496

Comparison of Parenteral Iron Sucrose and Ferric Chloride During Erythropoietin Therapy of Haemodialysis Patients: Original Article

Wu, Chih Jen, Lin, Hsin C., Lee, Kun F., Chuang, Chih K., Chen, Yi C., Chen, Han H. 01 February 2010 (has links)
Aim: To compare the effects of i.v. iron sucrose and Fe chloride on the iron indices of haemodialysis patients with anaemia. Methods: One hundred and eight haemodialysis patients receiving recombinant human erythropoiesis- stimulating agent (ESA) (mean age 59.37 years) were enrolled and randomly assigned to an iron sucrose or an Fe chloride group. Iron supplements were administered at 100 mg/week during the first 4 weeks (loading dose). Ferritin and transferrin saturation (TSAT) were then measured and dose adjusted. Ninety-eight subjects completed treatment; 51 in the iron sucrose group and 47 in the Fe chloride group. Ferritin, TSAT, haematocrit (Hct), reticulocyte count, serum albumin, fractional clearance of urea (Kt/V) and intact parathyroid hormone (iPTH) were measured. Results: There was no significant difference in baseline characteristics between the groups. Significant differences between the groups were observed in both iron indices and ESA dosage. Hct at week 24 (31.1% vs 29.7%, P = 0.006) and ferritin at week 20 (731.3 vs 631.7 ng/mL, P = 0.006) in the iron sucrose group were significantly higher than in the Fe chloride group. ESA dosage used in the iron sucrose group at week 8 was significantly lower than in the Fe chloride group (244.9 vs 322.6 U/kg per month, P = 0.003), and iron sucrose group received significantly lower iron dose than the Fe chloride group at week 8 (P = 0.005). Conclusion: Although the differences in ESA dosage, ferritin and iron dosage between two groups were found during the study period while similar results were shown at the end of 24 week study. Thus, iron sucrose and Fe chloride are safe and work equally well for haemodialysis patients.
497

Potencijal primene stabilisanog i „zelenom“ sintezom produkovanog nano gvožđa (0) za remedijaciju sedimenta kontaminiranog metalima / Potential application of stabilized and "green" produced nano zero -valent iron for remediation of sediment contaminated with metals

Slijepčević Nataša 02 October 2020 (has links)
<p>Ekolo&scaron;ki&nbsp; problem&nbsp; svetskih&nbsp; razmera&nbsp; predstavlja&nbsp; zagađenost&nbsp; sedimenta&nbsp; te&scaron;kim&nbsp; metalima, usled negativnih ekolo&scaron;kih efekata metala na životnu sredinu. Mnoge zemlje i regioni, kao i na&scaron;a zemlja&nbsp; suočavaju&nbsp; se&nbsp; sa&nbsp; ovom&nbsp; problematikom,&nbsp; koja&nbsp; je&nbsp; vrlo&nbsp; rasprostranjena&nbsp; usled&nbsp; sve&nbsp; brže urbanizacije&nbsp; i&nbsp; industrijalizacije,&nbsp; a&nbsp; sa&nbsp; sve&nbsp; većom&nbsp; nebrigom&nbsp; usled&nbsp; ispu&scaron;tanja&nbsp; otpadnih&nbsp; voda&nbsp; bez prethodnog&nbsp; preči&scaron;ćavanja&nbsp; u&nbsp; vodotokove.&nbsp; Prilikom&nbsp; promene&nbsp; uslova&nbsp; vodenog&nbsp; ekosistema,&nbsp; može doći do&nbsp; izluživanja&nbsp; metala&nbsp; i &scaron;tetnih efekata na&nbsp; životnu sredinu kao&nbsp; i&nbsp; na zdravlje&nbsp; ljudi. Stoga je remedijacija sedimenata zagađenih metalima ključna aktivnost u okviru procesa potpune sanacije vodenog ekosistema, a ekonomične, efikasne i ekolo&scaron;ki prihvatljive tehnike remedijacije su hitno potrebne&nbsp; i&nbsp; rado&nbsp; primenljive&nbsp; u&nbsp; tretmanu&nbsp; na&nbsp; velikoj&nbsp; skali.&nbsp; Pre&nbsp; primene&nbsp; remedijacione&nbsp; tehnike&nbsp; na velikoj skali, neophodna su ispitivanja pri laboratorijskim uslovima i pilot skali.&nbsp; Na kraju svakog uspe&scaron;nog&nbsp; laboratorijskog&nbsp; ispitivanja&nbsp; nalaze&nbsp; se&nbsp; pilot&nbsp; istraživanja.&nbsp; Pomoću&nbsp; njih&nbsp; se&nbsp; dobija&nbsp; p ravi odgovor u smislu izbora optimalne tehnologije imajući u vidu investicione i operativne tro&scaron;kove,<br />postignuti rezultat i krajnje ciljeve u pogledu upravljanja postrojenjem i otpadom. U ovom radu ispitan&nbsp; je&nbsp; potencijal&nbsp; primene&nbsp; stabilisanog&nbsp; i&nbsp; zelenom&nbsp; sinte zom&nbsp; produkovanog&nbsp; nano&nbsp; Fe(0)&nbsp; zaremedijaciju&nbsp; sedimenta&nbsp; zagađenog&nbsp; te&scaron;kim&nbsp; metalima.&nbsp; Kao&nbsp; remedijaciona&nbsp; tehnika&nbsp; odabrana&nbsp; je stabilizacija/solidifikacija,&nbsp; koja&nbsp; podrazumeva&nbsp; dodavanje&nbsp; agenasa&nbsp; za&nbsp; imobilizaciju&nbsp; metala&nbsp; u sedimentu&nbsp; sprečavajući&nbsp; time&nbsp; potencijalni&nbsp; rizik&nbsp;&nbsp; od&nbsp; izluživanja&nbsp; metala&nbsp; u&nbsp; životnu&nbsp; sredinu. Konvencionalni&nbsp; materijali&nbsp; poput&nbsp; letećeg&nbsp; pepela,&nbsp; cementa,&nbsp; gline&nbsp; se&nbsp; već&nbsp; odavno&nbsp; koriste&nbsp; u&nbsp; ovu svrhu. Kako u dana&scaron;nje vreme raste potražnja za novim, lako dostupnim agensima za stabilizaciju<br />sedimenta, do&scaron;lo se na ideju o primeni nanomaterijala na bazi gvožđa, tj. nano Fe(0) stabilisanog nativnom glinom&nbsp; i produkovanog redukcijom pomoću organskih&nbsp; molekula prirodno prisutnih u ekstraktu&nbsp; li&scaron;ća&nbsp; hrasta&nbsp; i&nbsp; crnog&nbsp; duda.&nbsp; Nanomaterijali&nbsp; su&nbsp; sintetisani&nbsp; i&nbsp; karakterisani&nbsp; različitim metodama&nbsp; i&nbsp; tehnikama.&nbsp; U&nbsp; nastavaku,&nbsp; u&nbsp; cilju&nbsp; efikasnosti&nbsp; njihove&nbsp; primene&nbsp; za&nbsp; stabilizaciju sedimenta, sprovedeni su ekstrakcioni i dinamički laboratorijski testovi izluživanja. Odabrane su sme&scaron;e sedimenta i nanomaterijala koje su pokazale najbolju efikasnost tr etmana. Nakon toga se ispitivanje&nbsp; nastavilo&nbsp; na&nbsp; pilot&nbsp; skali,&nbsp; gde&nbsp; se&nbsp; pratilo&nbsp; pona&scaron;anje&nbsp; nanomaterijala&nbsp; u&nbsp; zavisnosti&nbsp; od konvencionalnih&nbsp; materijala&nbsp; koji&nbsp; su&nbsp; već&nbsp; u&nbsp; literaturi&nbsp; dokumentovani&nbsp; kao&nbsp; efikasni&nbsp; imobilizacioni agensi. Dodatna potvrda uspe&scaron;nosti tretmana data je analizom i karakterizacijom s/s sme&scaron;a nakon pilot&nbsp; ispitivanja&nbsp; Na&nbsp; osnovu&nbsp; dobijenih&nbsp; rezultata&nbsp; proces&nbsp; se&nbsp; uspe&scaron;no&nbsp; pokazao&nbsp; pri&nbsp; laboratorijskim uslovima,&nbsp; a&nbsp; takođe&nbsp; i&nbsp; prilikom&nbsp; pilot&nbsp; tretmana,&nbsp; odnosno&nbsp; nakon&nbsp; pilot&nbsp; tretmana&nbsp; nije&nbsp; do&scaron;lo&nbsp; do povećanih koncentracija&nbsp; izluživanja metala iz s/s sme&scaron;a, kao ni degradacije sme&scaron;a nakon procesa ovlaživanja&nbsp; tokom&nbsp; &scaron;est&nbsp; meseci.&nbsp; Na&nbsp; osnovu&nbsp; toga,&nbsp; ovako&nbsp; tertirani&nbsp; sediment&nbsp; se&nbsp; može&nbsp; bezbedno odlagati&nbsp; na&nbsp; deponije,&nbsp; ili&nbsp; pak&nbsp; iskoristiti&nbsp; za&nbsp; &bdquo;kontrolisanu&ldquo;&nbsp; upotrebu,&nbsp; izgradnju&nbsp; puteva,kamenoloma, pomoćnih objekata i slično. Rezultati su doprineli u cilju trajnijeg re&scaron;avanja pitanja odlaganja&nbsp; zagađenog&nbsp; (izmuljenog)&nbsp; rečnog&nbsp; sedimenta,&nbsp; pri&nbsp; čemu&nbsp; se&nbsp; u&nbsp; procesu stabilizacije/solidifikacije&nbsp; dobijaju&nbsp; proizvodi&nbsp; sa&nbsp; dodatom&nbsp; vredno&scaron;ću&nbsp; neumanjenog&nbsp; kvaliteta .Nanomaterijali sintetisani u ovom radu na&nbsp; bazi ekstrakta li&scaron;ća biljaka doprinose kako očuvanju životne&nbsp; sredine,&nbsp; tako&nbsp; i&nbsp; ekonomičnosti&nbsp; primene&nbsp; remedijacione&nbsp; tehnike.&nbsp; Zahvaljujući&nbsp; velikoj specifičnoj&nbsp; povr&scaron;ini,&nbsp; malim&nbsp; dimenzijama&nbsp; čestica&nbsp; i&nbsp; velikom&nbsp; kapacitetu&nbsp; za&nbsp; imobilizaciju&nbsp; te&scaron;kih<br />metala predstavljaju efikasnu alternativu komercijalno dostupnim materijalima, &scaron;to ih čini veoma atraktivnim&nbsp; i&nbsp; obećavajućim&nbsp; u&nbsp; budućnosti&nbsp; pri&nbsp; tretmanu&nbsp; rečnog&nbsp; sedimenta&nbsp; zagađenog&nbsp; te&scaron;kim metalima.</p> / <p>The pollution of sediment by heavy metals represents a large environmental problem all<br />over the world.&nbsp; A&nbsp; lot of countries&nbsp; in the region&nbsp; as well as our country deal with this problem, which&nbsp; is&nbsp; widespread&nbsp; because&nbsp; of&nbsp; the&nbsp; fast&nbsp; urbanization&nbsp; and&nbsp; industrialization.&nbsp; There&nbsp; is&nbsp; more&nbsp; and more&nbsp; carelessness&nbsp; about&nbsp; wastewater&nbsp; discharge&nbsp; into&nbsp; water&nbsp; flows&nbsp; without&nbsp; previous&nbsp; purification. When the conditions of the aquatic ecosystem change, metal leaching and harmful effects on the environment&nbsp; and&nbsp; human&nbsp; health&nbsp; can&nbsp; occur.&nbsp; Therefore,&nbsp; remediation&nbsp; of&nbsp; metal-contaminated sediments&nbsp; is&nbsp; crucial&nbsp; activity&nbsp; in&nbsp; the&nbsp; process&nbsp; of&nbsp; the&nbsp; complete&nbsp; ecosystem&nbsp; remediation.&nbsp; Cost effective, efficient and environmentally friendly remediation techniques are urgently needed and readily applicable in large-scale treatment. Before applying remediation techniques on the largescale,&nbsp; both&nbsp; laboratory&nbsp; and&nbsp; pilot&nbsp; tests&nbsp; are&nbsp; necessary.&nbsp; There&nbsp; are&nbsp; pilot&nbsp; studies&nbsp; at&nbsp; the&nbsp; end&nbsp; of&nbsp; each successful&nbsp; laboratory&nbsp; test.&nbsp; Those&nbsp; studies&nbsp; provide&nbsp; the&nbsp; right&nbsp; answer&nbsp; in&nbsp; terms&nbsp; of&nbsp; choosing&nbsp; the optimal technology, taking into account the investment and operating costs,&nbsp;&nbsp; the achieved resultand&nbsp; the&nbsp; ultimate&nbsp; goals&nbsp; in&nbsp; terms&nbsp; of&nbsp; plant&nbsp; and&nbsp; waste&nbsp; management.&nbsp; In&nbsp; this&nbsp; study,&nbsp; the&nbsp; application<br />potential of stabilized and green&nbsp; -&nbsp; synthesized&nbsp; nano Fe(0) for the remediation of&nbsp; heavy&nbsp; metal&nbsp; -contaminated&nbsp; sediment&nbsp; was&nbsp; investigated.&nbsp; Stabilization&nbsp; /&nbsp; solidification&nbsp; technique&nbsp; was&nbsp; chosen&nbsp; as remediation technique which involves the addition of metal immobilizing agents in the sediment thus preventing the potential risk of metal leaching into the environment. Conventional materials such as fly ash, cement and clay have long been used for this purpose. Nowadays there is need for new, easily accessible agents for the sediment stabilization. Therefore it came up with the idea of&nbsp; using&nbsp; iron-based&nbsp; nanomaterials,&nbsp; ie.&nbsp; nano&nbsp; Fe(0)&nbsp; stabilized&nbsp; by&nbsp; native&nbsp; cla y&nbsp; and&nbsp; produced&nbsp; by reduction&nbsp; using&nbsp; organic&nbsp; molecules&nbsp; naturally&nbsp; present&nbsp; in&nbsp; oak&nbsp; and&nbsp; black&nbsp; mulberry&nbsp; leaf&nbsp; extract. Nanomaterials have been synthesized and characterized by different methods and techniques. In order&nbsp; to&nbsp; be&nbsp; effective&nbsp; in&nbsp; their&nbsp; application&nbsp; for&nbsp; sediment&nbsp; stabilization,&nbsp; extraction&nbsp; and&nbsp; dynamic laboratory leaching tests were performed. Mixtures of sediment and nanomaterials were selected that showed the best treatment efficiency.&nbsp; After that, the examination was continued on a pilot scale, where the behavior of nanomaterials was monitored, depending on conventional materials which&nbsp; have&nbsp; already&nbsp; been&nbsp; documented&nbsp; in&nbsp; the&nbsp; literature&nbsp; as&nbsp; effective&nbsp; immobilizing&nbsp; agents.Additional confirmation of treatment success was given by analysis and characterization of s / s mixtures&nbsp; after&nbsp; pilot&nbsp; testing.&nbsp; According&nbsp; to&nbsp; obtained&nbsp; results,&nbsp; the&nbsp; process&nbsp; was&nbsp; successfully demonstrated&nbsp; under&nbsp; laboratory&nbsp; conditions,&nbsp; and&nbsp; also&nbsp; during&nbsp; the&nbsp; pilot&nbsp; treatment.&nbsp; After&nbsp; the&nbsp; pilot treatment&nbsp; there&nbsp; were&nbsp; no&nbsp; increased&nbsp; concentrations&nbsp; of&nbsp; metal&nbsp; leaching&nbsp; from&nbsp; s/s&nbsp; mixtures,&nbsp; nor mixture degradation after the wetting process for six months. Based on that, the sediment treated in this way&nbsp; can&nbsp; be safely disposed of&nbsp; in&nbsp; landfills, or used&nbsp; for &quot;controlled&quot; use, construction of<br />roads,&nbsp; quarries,&nbsp; auxiliary&nbsp; facilities&nbsp; and&nbsp; etc.&nbsp; The&nbsp; results&nbsp; have&nbsp; contributed&nbsp; to the&nbsp; goal&nbsp; of&nbsp; a&nbsp; more permanent solution to the issue of disposal of polluted (slugged) river sediment, whereby in the process&nbsp; of&nbsp; stabilization/solidification,&nbsp; products&nbsp; with&nbsp; added&nbsp; value&nbsp; of&nbsp; undiminished&nbsp; quality&nbsp; are obtained. The nanomaterials synthesized in this paper on the basis of plant leaf extract contribute to both the preservation of the environment and the economy of remediation techniques. Thanks to their&nbsp; large specific&nbsp; surface area, small particle size and&nbsp; large ca pacity&nbsp; for&nbsp; immobilization of heavy&nbsp; metals,&nbsp; they&nbsp; represent&nbsp; an&nbsp; effective&nbsp; alternative&nbsp; to&nbsp; commercially&nbsp; available&nbsp;&nbsp; materials.&nbsp; It makes&nbsp; them&nbsp; very&nbsp; attractive&nbsp; and&nbsp; promising&nbsp; in&nbsp; the&nbsp; future&nbsp; in&nbsp; the&nbsp; treatment&nbsp; of&nbsp; river&nbsp; sediment contaminated with heavy metals.</p>
498

SURFACE ROUGHNESS AND SUPERHYDROPHOBICITY BEHAVIOR IN ELECTROCHEMICALLY-ETCHED FE- AND NI-BASED ALLOYS

Benjamin P Smith (11820377) 09 December 2021 (has links)
<blockquote><div><div>Methods and techniques for tailoring the surface morphology of metallic surfaces are determined in part by the complex behavior of elemental interactions in conjunction with electrochemical reactions. In this work, we show how the surface morphology can be predicted based on experimental data resulting from polarization curves and compositional differences of Fe- and Ni-based superalloys. Electrochemical treatments utilizing NaCl as the electrolyte were adapted using parameters such as the pitting resistance equivalent (PRE) number and polarization curves to obtain both rough and smooth surfaces. Utilizing these metrics, we electrochemically etched Inconel 600, SS304, Inconel 718 and Inconel 625 obtaining average surface roughness values that ranged from 0.05 to 57.4 μm indicating the success of tailoring the technique to obtaining rough and smooth surfaces. The effect of current density, current pulsing, and temperature were varied to elucidate roughness and pitting behavior, and strong correlations to the PRE number and polarization curve properties of the alloy were observed. Heat treatments and subsequent evolution to the microstructure in the form of grain growth and precipitation altered the etching behavior. These techniques can be used in preventing corrosion failure and enhancing electrochemical machining</div></div></blockquote>
499

Numerische Untersuchung von Abhilfemaßnahmen gegen tangentiale Wanderbewegungen von Wälzlagerringen

Schiemann, Tom, Leidich, E. 08 May 2014 (has links)
In diesem Beitrag werden neben der detaillierten Betrachtung der Wandervorgänge von Lagerringen primär die Simulationsmethodik bezüglich elastischer Zwischenschichten sowie die Ergebnisse einer FE-Parameterstudie präsentiert. Der Fokus liegt dabei auf Wälzlageraußenringen von Radiallagern unter Punktlast.
500

Dry Oxidation of Ferrous and Mixed-valence Smectites and Its Implications for the Oxidative History of Mars

Araneda Noboa, Paula, 0000-0002-7727-0231 January 2021 (has links)
Phyllosilicates are widespread on Noachian to Early Hesperian terrains on Mars and can help constrain the planet’s geologic and environmental history, particularly its aqueous and redox history, which in turn can provide clues about past habitability. A range of ferrous and mixed-valence smectites were synthesized and then exposed to varying O2 fluxes under dry conditions to determine if Fe/Mg trioctahedral smectites can be oxidized without an aqueous medium to form dioctahedral smectites like those observed on the surface of Mars. The appearance of a secondary peak in some unaltered samples indicates a separate phase formed during synthesis, which remained throughout the oxidation process. Partial oxidation was achieved by all samples, but only those with the highest starting Fe3+ content reached almost complete oxidation. Rapid initial oxidation was observed for all samples, but seemed to subside before oxidation was complete, indicating the process becomes unfavorable after a certain point. All three O2 fluxes used in this study were successful in partially oxidizing the smectite samples but no correlation was observed between O2 flux and actual amount of oxidation, i.e., a higher O2 flux does not necessarily result in higher production of ferric iron. The process of oxidation did cause octahedral sheet contraction in some cases; however, in some samples octahedral sheet expansion was observed with oxidation. No additional phases were formed upon oxidation and no Fe ejection was observed. Overall, the amount of oxidation observed for all samples indicates that O2 alteration of trioctahedral smectites into dioctahedral smectites can proceed under dry conditions, meaning oxidation could have continued on Mars after surface water dried up. / Geology

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