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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.
141

The isotopic composition of lead and strontium from the volcanic rocks of the islands of the South Pacific

Swainbank, Ian G. January 1968 (has links)
Thesis--Columbia University. / Bibliography: leaves 121-124.
142

The influence of PFA particle size on the workability of cementitious pastes

Pretorius, Jan Hendrik Christoffel. January 2005 (has links)
Thesis (M.Sc.(Civil Engineering))--University of Pretoria, 2002. / Summary in English. Includes bibliographical references.
143

Stratigraphy and origin of tuffs in the Stanley Group (Mississippian), Ouachita Mountains, Oklahoma and Arkansas

Niem, Alan R. January 1971 (has links)
Thesis--University of Wisconsin. / Vita. Includes bibliographical references (leaves 130-137).
144

The durability of concrete containing high levels of fly ash

Burden, Donald. January 2006 (has links)
Thesis (M.A.)--University of New Brunswick, 2003. / Copyright (2003) held by author. Includes bibliographical references (p. 97-100).
145

The effects of fly ash on the ability to entrain and stabilize air in concrete

Ley, Matthew Tyler, January 1900 (has links)
Thesis (Ph. D.)--University of Texas at Austin, 2007. / Vita. Includes bibliographical references.
146

Soil volcanic ash and Douglas-fir (Pseudotsuga menziesii (Mirb.) Franco var. glauca) productivity in north central Idaho /

Kimsey, Mark James. January 1900 (has links)
Thesis (Ph. D.)--University of Idaho, 2006. / Abstract. "May 2006." Includes bibliographical references. Also available online in PDF format.
147

The effective viscosity of ash-laden flows

Burns, Kirstin Anne. January 2007 (has links)
Thesis (M.S.)--University of Montana, 2007. / Title from title screen. Description based on contents viewed July 18, 2007. Includes bibliographical references (p. 96-98).
148

Stratigraphy of the Upper Miocene volcanic rocks of the Island of Kos, Greece : geodynamic implications /

Tsoukalas, Nikolaos. January 2008 (has links)
Thesis (M.Sc.)--Saint Mary's University, 2008. / Includes abstract. Supervisor: Georgia Pe-Piper. Includes bibliographical references (leaves 141-148).
149

Πειραματική καλλιέργεια ηλίανθου σε υπόστρωμα τέφρας με στόχο την εκτίμηση περιβαλλοντικών συνθηκών

Αναστασίου, Δημήτριος 02 February 2011 (has links)
Πραγματοποιήθηκε πείραμα με στόχο τη μελέτη των περιβαλλοντικών συνθηκών πειραματικής καλλιέργειας ηλίανθου σε υπόστρωμα τέφρας. Για την μελέτη του θέματος εγκαταστάθηκε πειραματικός αγρός στην παραλιακή περιοχή του χωριού Μηλάκι του δήμου Ταμυνέων (Αλιβερίου) στο νομό Ευβοίας. Η σπορά του ηλίανθου έγινε με την φύτευση σπόρου με το χέρι στις 27 Απριλίου του 2009 σε δυο διαφορετικά υποστρώματα, της ήδη υπάρχουσας στην περιοχή, τέφρας και σε κανονικό εδαφικό υπόστρωμα το οποίο μεταφέρθηκε στην περιοχή. Για τις ανάγκες του πειράματος χρησιμοποιήθηκαν και στα δυο υποστρώματα τα πιο κάτω εδαφοβελτιωτικά (γύψος, τύρφη, περλίτης, πριονίδι) καθώς και αναμείξεις αυτών. Η μέγιστη τιμή του ολικού ύψους των φυτών στο υπόστρωμα της τέφρας, παρατηρείται στις 18 Ιουλίου του 2009, ενώ για την παράμετρο της διαμέτρου των ανθοκεφαλών η μέγιστη τιμή της παρατηρείται στις 2 Αυγούστου του 2009. Τα ίδια συμπεράσματα προκύπτουν και από τα δεδομένα που ελήφθησαν από το κανονικό εδαφικό υπόστρωμα. Υπολογίστηκαν οι συντελεστές συσχέτισης των φυτικών παραμέτρων στα διάφορα πειραματικά πεδία. Αυτές έδειξαν ότι οι θετικές αλλά και οι αρνητικές συσχετίσεις μεταξύ των ίδιων συγκρινόμενων παραμέτρων (Μεσοδιάστημα Κοτύλη – 1ο φύλλο, Μεσοδιάστημα 1ο φύλλο – 2ο φύλλο, Ολικό ύψος, Φυλλική επιφάνεια 1ου φύλλου, Φυλλική επιφάνεια 2ου φύλλου, Διάμετρος ανθοκεφαλής, Βάρος φυτού), είναι μεγαλύτερες στο υπόστρωμα της τέφρας από αυτό του κανονικού εδαφικού υποστρώματος. Εξαίρεση αποτελούν δυο περιπτώσεις, όπου στο υπόστρωμα της τέφρας εμφανίζεται αρνητική συσχέτιση ενώ στο κανονικό εδαφικό υπόστρωμα εμφανίζεται θετική συσχέτιση. Διαπιστώθηκε ότι στο υπόστρωμα της τέφρας, οι μεγαλύτερες τιμές των παραμέτρων που μετρήθηκαν κατά τη διάρκεια του πειράματος παρατηρήθηκαν στα πειραματικά τετράγωνα με τα παρακάτω εδαφοβελτιωτικά: T5A, G.T4A, G.T5A, G.T.PL3A και G.T.PL4A. Στο κανονικό εδαφικό υπόστρωμα, διαπιστώθηκε ότι οι μεγαλύτερες τιμές των παραμέτρων που μετρήθηκαν κατά τη διάρκεια του πειράματος παρατηρήθηκαν στα πειραματικά τετράγωνα με τα παρακάτω εδαφοβελτιωτικά: G.T5B, G.T.PL4B, G.T.PL5B, G.T.PL.PN4B και G.T.PL.PN5B. / An experiment was realised amining at the study of environmental conditions experimental growing of sunflower in sublayer of ash. For the study of this subject was installed experimental field in the coastal region of the village Milaki at the municipality Tamyneon (Aliveriou) in the prefecture of Evia. The seeding of sunflower became with the planting of seed by hands on 27 April 2009 in two different sublayers, the already existing in the region, ash and in regular territorial sublayer which was transported in the region. For the needs of experiment they were also used in the two sublayers the below ameliorative of ground (gypsum, peat, perlite, sawdust) as well as mixtures of these. The biggest price of the total height of plants in the sublayer of ash, is observed on 18 July 2009, while for the parameter of heads diameter her biggest price is observed on 2 August 2009. The same conclusions also result from the data that were received from the regular territorial sublayer. They were calculated the correlation factors of the plant parameters in the various experimental fields. These showed that positive but also negative correlations between the same compared parameters (Cotyledon – first leaf interval, First leaf – second leaf interval, Total height, Leaf surface of first leaf, Leaf surface of second leaf, Head diameter, Weight of plant) are bigger in the sublayer of the ash from that of the regular territorial sublayer. Exception constitutes two cases, where in the sublayer of ash is presented negative correlation while in the regular territorial sublayer is presented positive correlation. It was realised that in the sublayer of ash, the biggest prices of the parameters that were measured at the duration of experiment were observed in the experimental squares with the following ameliorative of ground: T5A, G.T4A, G.T5A, G.T.PL3A και G.T.PL4A. In the regular territorial sublayer, was realised that the biggest prices of the parameters that were measured at the duration of experiment were observed in the experimental squares with the following ameliorative of ground: G.T5B, G.T.PL4B, G.T.PL5B, G.T.PL.PN4B και G.T.PL.PN5B.
150

Fly Ash Zeolite Catalyst Support for Fischer-Tropsch Synthesis

Campen, Adam 01 December 2012 (has links)
This dissertation research aimed at evaluating a fly ash zeolite (FAZ) catalyst support for use in heterogeneous catalytic processes. Gas phase Fischer-Tropsch Synthesis (FTS) over a fixed-bed of the prepared catalyst/FAZ support was identified as an appropriate process for evaluation, by comparison with commercial catalyst supports (silica, alumina, and 13X). Fly ash, obtained from the Wabash River Generating Station, was first characterized using XRD, SEM/EDS, particle size, and nitrogen sorption techniques. Then, a parametric study of a two-step alkali fusion/hydrothermal treatment process for converting fly ash to zeolite frameworks was performed by varying the alkali fusion agent, agent:flyash ratio, fusion temperature, fused ash/water solution, aging time, and crystallization time. The optimal conditions for each were determined to be NaOH, 1.4 g NaOH: 1 g fly ash, 550 °C, 200 g/L, 12 hours, and 48 hours. This robust process was applied to the fly ash to obtain a faujasitic zeolite structure with increased crystallinity (40 %) and surface area (434 m2/g). Following the modification of fly ash to FAZ, ion exchange of H+ for Na+ and cobalt incipient wetness impregnation were used to prepare a FTS catalyst. FTS was performed on the catalysts at 250 - 300 °C, 300 psi, and with a syngas ratio H2:CO = 2. The HFAZ catalyst support loaded with 11 wt% cobalt resulted in a 75 % carbon selectivity for C5 - C18 hydrocarbons, while methane and carbon dioxide were limited to 13 and 1 %, respectively. Catalyst characterization was performed by XRD, N2 sorption, TPR, and oxygen pulse titration to provide insight to the behavior of each catalyst. Overall, the HFAZ compared well with silica and 13X supports, and far exceeded the performance of the alumina support under the tested conditions. The successful completion of this research could add value to an underutilized waste product of coal combustion, in the form of catalyst supports in heterogeneous catalytic processes.

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