732 research outputs found
An in situ XAS study of high surface-area IrO2 produced by the polymeric precursor synthesis
No full textIridium oxide powders with a surface area of more than 1 m2 g-1 (4 m2 g-2 from the H-UPD charge) and iridium-oxide crystallites less than 10 nm across were synthesized by heat treating gels formed from citric acid, ethylene glycol and dihydrogen hexachloroiridate(iv) in air. The characteristics of the resulting material was found to be strongly dependent on the heat-treatment step in the synthesis. A single heat-treatment of the gel resulted in a material with a substantial fraction of elemental iridium metal, i.e. iridium in oxidation state zero (Ir0). Post-synthesis modification of the powder by potential cycling resulted in oxidation peaks consistent with the conversion of the metal phase to iridium oxide. Linear combination of the near-edge part of the X-ray absorption data (X-ray absorption near-edge spectroscopy, XANES) collected in situ during potential cycling and an analysis of the extended X-ray fine-structure (EXAFS) part of the spectrum showed that the overall metal fraction was not significantly affected by the cycling. The oxidation of the metal phase is therefore limited to a thin layer of oxide at the metal surface, and a significant part of the iridium is left inactive. A modification of the heat treatment procedure of the sample resulted in iridium oxide containing only insignificant amounts of elemental iridium metal.</p
Experiences from Nobel Creations : Technology and creativity in music production for museum exhibitions
No full textAldo Leopold: A Sand County Almanac
No full textThis lecture on Aldo Leopold\u27s A Sand County Almanac, delivered at Lawrence University on January 22, 2003, was designed for students and faculty in the college\u27s Freshman Studies program. Freshman Studies, a multidisciplinary introduction to the liberal arts, has been the cornerstone of the Lawrence curriculum for over fifty years. The lecturer, Peter Fritzell, is professor of English and the Patricia Hamar Boldt Professor of Liberal Studies at Lawrence. Professor Fritzell holds the M.A. and the Ph.D. from Stanford University. He has published widely in the area of nature writing
Sustainability Reporting in the North American Tourism Industry: Research Paper
No full textPeer reviewedGreg McCullu
Strategies for the analysis of the metallic fraction of Ir and Ru oxides via XRD, XANES, and EXAFS
No full textIridium and ruthenium oxide are active electrocatalysts for oxygen evolution. The relation between preparation method, structure, and behavior of mixed oxides of iridium and ruthenium are of interest in order to obtain active and stable catalysts. In this work the structure of mixed Ru–Ir oxides synthesized by the polymeric precursor method, which involves the formation of a gel containing the metal precursors and subsequent heat-treatment in air, was studied for the IrxRu1−xO2 system. An in-depth analysis of X-ray diffraction (XRD) and X-ray absorption (XAS) data, including EXAFS and linear combination of XANES, shows that the polymeric precursor synthesis method is capable of providing an intimate mixing of Ir and Ru in the catalyst. In addition to the oxide phase, metal phases, i.e. with Ru or Ir or both in oxidation state zero (Ir(fcc) and Ru(hcp)), were also found in the product materials. Facing complex structures such as some of those synthesized here, we have shown that a representation of shells with more than one atom type are efficiently represented using mixed sites, i.e. including scattering contributions from several elements in a site corresponding to a partial occupancy of the site by these elements, this method forming a very efficient basis for analyzing EXAFS data
Coupled model of electromagnetic actuator with longer pull-in time
No full textTáto diplomová práca rieši problematiku modelovania elektromagnetických aktuátorov a súčasne aj modelovania magnetických silových polí. Teoretický rozbor tejto problematiky je v časti venovanej matematickému modelu a model konkrétneho zariadenia je v nasledujúcich kapitolách. K diplomovej práci sú pridané prílohy obsahujúce konkrétne numerické výpočty.This master thesis solves the modeling of electromagnetic actuators and also the modeling of magnetic force fields. Theoretical analysis of this issue is in part dedicated to mathematical models and specific device in the following chapters. In the end of the master thesis are added annexes containing specific numerical calculations
II. Sobre el vasco hamaika «11» (en relación con el artículo de I. Bochoroshvili sobre el mismo tema)
No full textThe author of this work admits that the numeral meaning of the term hamar «10» is older than «amai», end, limit in the word hameka, going back to the meaning of «hand» (mano), although it contributes with the observation that other languages had a numeral, eka, ika, to indicate the number «1».
The second part brings a complementary explanation that poses Prof. Zystar in favour of the old position accepted by Michelena, which sees the numeral hamar «10» in the base of the term hamaika, opposite to Tovar's hypothesis which sets of amai, end, limit, extreme. La autora de este trabajo admite que la acepción numeral del término hamar «10» es más antigua que la de «amai», fin, límite, en la palabra hameka, remontándose al significado de «mano», aunque asume ambos conceptos. Aporta la observación de que otras lenguas poseían un numeral, eka, ika, para indicar el número «1».
La segunda parte aporta una aclaración complementaria que posiciona al prof. Zytsar a favor de la postura antigua admitida por Michelena, que ve el numeral hamar «10» en la base del término hamaika, frente a la hipótesis de Tovar que parte de amai, fin, límite, extremo. Lanaren egiliearentzat hamar «10» zenbakiaren erroa zaharragoa da «amai», bukaera, azkena, hitzarena baino, eta «eskua» adierazten zuen noizbait. Gero, hamar eta amai edukin biak hartu zituen noski. Beste hizkuntza batzuetan ere bazela eka, ika, bat «1» zenbakia adierazteko, aditzera ematen du.
Bigarren atala bestearen gehigarria da eta Zytsar jauna Mitxelena-ren alde agertzen da «hamar» zenbatzailea ikusten duelarik «hamaikaren» erroan, eta ez Tovar jaunak proposatutako amai hitza, bukaera, azkena, aideraziz. 
Equus onager Boddaert 1785
No full textEquus onager Boddaert, 1785. Elench. Anim., p. 160. TYPE LOCALITY: NW Persia (= Iran), Kasbin, near Caspian. DISTRIBUTION: Formerly Kazakhstan north to upper Irtysh and Ural Rs. (Russia); westward north of the Caucasus and Black Sea at least to Dniestr River (Ukraine); and SE of Caspian Sea, Anatolia, N Iraq, Iran, Afghanistan, and Pakistan to Thar Desert of NW India; survives as isolated populations in Rann of Kutch (India), Badkhys Preserve, Turkmenia, and C Iran; also reestablished on Barsa-khelmes Isl (Aral Sea, Uzbekistan). STATUS: CITES - Appendix I E. hemionus khur; IUCN - Endangered as E. h. khur, Extinct as £. h. hemippus. SYNONYMS: bahram, blanfordi, dzigguetai, hamar, hemippus, indicus, khur, kulan, syriacus. COMMENTS: Revised by Groves and Mazak (1967), who with Groves (1986) and Schlawe (1986) included onager in hemionus, but Bennett (1980) considered onager a distinct species.Published as part of Peter Grubb, 1993, Order Perissodactyla, pp. 369-372 in Mammal Species of the World (2 nd Edition), Washington and London :Smithsonian Institution Press on page 370, DOI: 10.5281/zenodo.735311
Cold Saline Perfusion before Ischemia-Reperfusion Is Harmful to the Kidney and Is Associated with the Loss of Ezrin, a Cytoskeletal Protein, in Rats
No full textBackground: Organ protection for transplantation is perfusion with ice-cold preservation solutions, although saline is also used in animal experiments and living donor transplantations. However, ice-cold perfusion can contribute to initial graft injury. Our aim was to test if cytoskeletal damage of parenchymal cells is caused by saline itself or by the ice-cold solution. Methods: F344 rat kidneys were flushed with cold (4 degrees C) saline, ischemic and sham kidneys were not perfused. In a separate set, F344 kidneys were flushed with saline or preservation solution at 4 or 15 degrees C. Ischemia time was 30 min. Results: Renal injury was significantly more severe following cold ischemia (CI) than after ischemia-reperfusion without flushing (ischemia/reperfusion (I/R)). Functional and morphologic damage was accompanied by severe loss of ezrin from glomerular and tubular epithelial cells after CI. Moreover, saline caused serious injury independently from its temperature, while the perfusion solution was more beneficial, especially at 4 degrees C. Conclusions: Flushing the kidney with ice-cold saline can cause more severe injury than ischemia-reperfusion at body temperature even during a short (30 min) ischemia. Saline perfusion can prolong recovery from ischemia in kidney transplantation, which can be prevented by using preservation solutions.Peer reviewe
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