No description available.

The central part of the Front Range mineral belt, Colorado, is a Precambrian crystalline basement terrain intruded by early Tertiary porphyries and closely associated mesothermal ore deposits. The ore deposits are gold- and silver-bearing base metal sulphide-quartz veins arranged in more or less well developed concentric mineral zones centred on concealed porphyry plutons. Central areas of pyritic mineralisation are surrounded by peripheral zone of galena-sphalerite-bearing veins, often separated by a transitional zone of composite mineralisation. Molybdenite-bearing and uraninite-bearing veins are locally abundant proximal to the central pyritic zones and are closely associated spatially and temporally with highly evolved quartz bostonite intrusions. The mineral veins are enveloped in narrow selvages of sericitized and argillized wallrock and are entirely fracture controlled. A low density lithogeochemical survey of the country rocks revealed strong lithological controls on the distributions of selected trace elements and radiation emission values. Positive Rb/Sr anomalies are tentatively linked to concealed intrusions, and corresponding positive anomalies of Pb, Zn, Mo and W are associated with known molybdenite mineralisation. Sericitized rocks are characterised by low Sr and enhanced Rb, Zn, Pb, Mo and Ag values, and areas of depleted country rock Sr values may be related to vein wallrock alteration. D/H and <SUP>18</SUP> O/<SUP>16</SUP> O signatures of fresh country rocks indicate variable magmatic water overprinting and similar analyses of sericitised rocks show that alteration was accomplished by magmatic hydrothermal fluids at 340<SUP>o</SUP> -515<SUP>o</SUP> C. Mineralisation and alteration in the area were caused by hydrothermal fluids evolved from highly differentiated Laramide quartz bostonite intrusions. K-Ar ages of ca. 62 Ma have been obtained from alteration sericites from the peripheral mineral zone. Similar studies in the central pyritic zone have yielded ages of ca. 59 Ma suggesting the existence of long lived hydrothermal activity in the area characterised by widespread high-temperature alteration, followed by thermal decay and collapse towards core zones. The ore deposits investigated during this study display numerous features in common with porphyry-style and other intrusive-related mineralisation characteristic of Cordilleran terrains, but also exhibit significant differences. The combination of these features contribute to the distinct and possibly unique character of these mineral deposits.

No description available.

The concept of a front plays a decisive role in various elds in physics and beyond. In the present thesis we study key aspects of front dynamics and stability in the context of laser plasmas, organic semiconductors and quantum media. In laser plasmas, we investigate the hydrodynamic instabilities developing at the fronts of laser deagration (ablation). Using direct numerical simulations, we nd noticeable velocity increase of the Rayleigh-Taylor bubble at a deagration front in comparison with that arising at an inert interface. We study the Darrieus-Landau instability of laser deagration accounting for the specific features of the fusion plasmas: strong temperature dependence of the thermal conduction and sonic velocities of the plasma flow. We find that these features of the laser plasmas make the Darrieus-Landau instability stronger by a factor of 3 in comparison with the well-known case of slow flames. We clarify the experimental conditions required for observations of the Darrieus-Landau instability in laser plasmas. In quantum plasmas, we study interplay of the classical and quantum eects for shock waves and for the pseudo-ferrouid instability. For shocks in quantum plasmas, we demonstrate transition from a monotonic Burgers classical shock structure to the train of oscillations (solitons) in the quantum limit. We obtain also a counterpart of the ferrouid instability in quantum magnetized plasmas due to collective spin-dynamics in an external magnetic eld. We discuss importance of the instability for thermonuclear explosions of white dwarfs in the Supernovae Ia events. In organic semiconductors, we develop the theoretical and numerical model of the electrochemical doping fronts. The study is based on the modifed mobilitydiffusion approach to the complex semiconductor plasmas consisting of holes, electrons, positive and negative ions. The m odel describes the doping front structure and predicts the front velocity in a very good agreement with the experiments. We discover a new fundamental instability, which distorts the doping fronts and speeds-up the process considerably. We demonstrate how the instability may be controlled and used to improve performance of optoelectronic devices. Finally, we study avalanches of spin-switching in crystals of nanomagnets, which may be described as magnetic deagration and detonation due to striking resemblance to the respective combustion phenomena. We find that magnetic deflagration becomes unstable and propagates in a pulsating regime when potential barrier of the spin-switching is sufficiently high in comparison with the energy release in the process. We also demonstrate the possibility of magnetic detonation in the crystals, which explains the astounding effect of ultra-fast spin-avalanches encountered in recent experiments. We find that magnetic detonation does not destroy the unique properties of the crystals, a very important conclusion in view of possible applications of nanomagnets in quantum computing. / Konceptet med en utbredningsfront spelar en avgörande roll inom många olika områden i fysik. I denna avhandling studeras centrala aspekter av utbredningsfronters dynamik och deras stabilitet i för laser-plasmaväxelverkan, organiska halvledare samt kvantmedier.  För laser-plasmaväxelverkan har vi undersökt de hydrodynamiska instabiliteter, som t ex Rayleigh-Taylor-instabiliteten, vilka utvecklas vid deflagrationsfronter (under så kallad laserablation). Med hjälp av direkta numeriska simuleringar har vi hittat en märkbar hastighetökning av Rayleigh-Taylor bubblan i en deaflgrationsfront jämfört med det som kan ses vid ett inert gränssnitt. Vi har även studerat Darrieus-Landau-instabiliteten vid laserdeflagration, speciellt hur denna påverkas av de specifika egenskaperna hos ett fusionsplasma: ett starkt temperaturberoende hos värmeledningen samt plasmaflödet som uppnår ljudhastighet. Vi har funnit att dessa egenskaper hos laser-plasmasystem gör Darrieus-Landau instabilitet starkare jämfört med det vanliga fallet av långsamma flammor. Vi har även klargjort de experimentella förutsättningar som krävs för observationer av Darrieus-Landau instabilitet i laser-plasmasystem.  Vi har studerat samspelet mellan klassiska och kvantmekaniska aspekter i kvantplasmor. Specifikt har vi undersökt chockvågors utbredning och dynamik samt instabiliteter i pseudo-ferrofluider. För chocker i kvantplasmor har vi visat att en övergång från Burgers klassiska monotona chockstruktur till ett vågtåg av solitoner sker i kvantgränsen. Vi för också en motsvarighet till ferrofluidinstabiliter i magnetiserade plasmor  på grund av dess kollektiva spinn-dynamik i ett yttre magnetfält. Vi har diskuterar instabilitetens roll för termonukleära explosioner hos vita dvärgar i supernovor av typ Ia.   I organiska halvledare har vi utvecklat en teoretisk och numerisk modell av elektrokemiska dopningsfronter. Studien är baserad på en modifierade drift-diffusiondmodell för komplexa dopade halvledare, vilka består av hål, elektroner, positiva och negativa joner. Modellen beskriver dopningsstrukturen och gör det möjligt att beräkna dopningsfrontens hastighet med värden som överensstämmer mycket väl med experimenten. Vi har även upptäckt en ny grundläggande instabilitet, vilket gör dopningsfronter anisotrop och snabbar upp processen betydligt. Vi visar hur instabilitet kan styras och användas för att förbättra optoelektronisk utrustning.   Slutligen studerar vi laviner av spin-växlingar i kristaller bestående av nanomagneter. Denna process kan beskrivas i termer av ett nytt analogt koncept, så kallad magnetiska deflagration och detonation, på grund av de slående likheter dessa har till motsvarande förbränningsfenomen. Vi har funnit att magnetiska deflagration blir instabil och propagerar i en pulserande regim när potentialbarriären för spin-växling är tillräckligt hög i jämförelse med frigörelsen av energi i processen. Vi visar också möjlighet till magnetisk detonation i dessa  kristaller, vilket förklarar de ultrasnabba spin-laviner man stött på under vid experiment helt nyligen. Denna magnetiska detonation förstör inte de unika egenskaperna hos kristallerna, en mycket viktig slutsats med tanke på möjliga tillämpningar av nanomagneter i kvantdatorer.

Thesis (B.A.Hons. 1978) from the Department of History, University of Adelaide.

Issued also as thesis, Basel. / Bibliography: p. 479-486.

Thesis (M.A.)--Wisconsin. / Includes bibliographical references (leaves 222-226).

Thesis (M.A.)--University of Wisconsin--Madison, 1970. / eContent provider-neutral record in process. Description based on print version record. Includes bibliographical references.

Im Buchh. als : Wesen u. Wirkungen d. Publizistik. Bd 8. - Leipzig, Phil. Diss. v. 1. März 1937. (Nicht f. d. Austausch).

Orientador : Ariovaldo Umbelino de Oliveira / Banca: Antonio Thomaz Júnior / Banca: Miriam Claudia Lourenção Simonetti / Resumo: Esta dissertação tem como objetivo principal analisar a apropriação capitalista da terra através dos avanços da frente de expansão e da frente pioneira e a formação da pequena propriedade no município de Jales, Estado de São Paulo. A apropriação ocorreu de forma ilícita por meio da indústria de grilagem de terras no extremo Noroeste Paulista no decorrer do século XX. Em Jales, a apropriação capitalista foi realizada pelo engenheiro Euphly Jalles. Após a década de 1940, Jalles montou estratégias de venda de pequenos lotes de terras a trabalhadores rurais provenientes de outras regiões do Estado e do Brasil, antigos colonos e parceiros. Como estratégias, foram fundadas duas cidades - Jales e São Francisco -, abertas estradas e realizado o parcelamento no pagamento das vendas de terras. Centenas de famílias foram conduzidas a Jales para a realização do sonho da propriedade da terra e, por outro lado, para concretizar os interesses mercantis por meio da extração da renda capitalista da terra realizada pelos especuladores imobiliários. Entre as décadas de 1960 e 1980, muitos pequenos proprietários de terras, que compraram suas propriedades de Euphly Jalles, sofreram ações de despejo e cobrança por novos pagamentos efetuada pelo surgimento de outro proprietário dessas áreas. Essas famílias viveram um verdadeiro drama social. Mesmo assim, houve a manutenção da pequena propriedade, tanto em área como em número, característica do espaço geográfico do município de Jales. / Abstract: This dissertation is mainly aimed to analyse the capitalist seizure of land, through the advance the expansion and pioneers fronts and the small property formation in Jales, a town in the state of São Paulo. The seizure happened illegally, through the industry of faking land documents in the extreme northwest of São Paulo state during the 20th century. In Jales, the capitalist seizure was managed by the engineer Euphly Jalles. After the 1940 decade, Jalles created sale strategies of small pieces of land to rural workers coming from other regions of the state and the country, former workers and partners. Strategically two towns were founded - Jales and São Francisco -, dirt roads were opened and the payments of the lands were divided. Hundreds of families were conducted to Jales in order to fulfill the dream of owning a property and, on the other hand, to achieve the market interest through the extracting capitalist dividends from the land carried out by the real state speculators. Between the 60's and 80's, many small land owners who bought their properties from Euphly Jalles, were sued, being evicted and forced to repay to the real owners of those areas. These families faced a true social drama. However, the small property was maintained both in size and in quantities, typical of the geographical space in Jales. / Mestre