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The quantum theory of antiferromagnetismJanuary 1950 (has links)
[by] R.J. Harrison. / "This report is based on a Doctoral thesis in the department of Physics, Massachusetts Institute of Technology." / Bibliography: p. 31. / Army Signal Corps Contract No. W-36-039 sc-32037. Dept. of the Army Project No. 3-99-10-022.
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Apologies in the discourse of politicians : a pragmatic approachMurphy, James January 2014 (has links)
In this thesis, I analyse apologies produced by British political figures from a pragmatic perspective. In particular, I seek to explain the function of political apologies and describe the form they take. In order to give a thorough account of the speech act of apologising in the public sphere, I look to a variety of genres for data. The set of remedial acts scrutinised in this study come from debates and statements in the House of Commons, the Leveson Inquiry and news interviews. The differences in communicative practices between these data sources mean that the types of apology that come about within each genre are varied. Many of the parliamentary apologies are monologic, whereas the apologetic actions found at the Leveson Inquiry and in news interviews are dialogic and, to some extent, co-constructed between participants. These differences mean that a variety of theoretical approaches are taken in analysing the data – speech act theory (Austin, 1962; Searle, 1969) and generalised conversational implicature theory (Levinson,2000) feature heavily in the discussion of monologic apologies. Apologies produced within an interactive, ‘conversational’ setting are treated using developments in conversation analysis (amongst others see: Sacks, 1992; Schegloff, 2007). I attempt to reconcile these two, quite different, approaches to discourse at various points in the thesis, arguing that conversation analysis lacks a theory of how interlocutors understand what actions are happening in interaction (and this is provided by speech act theory) and speech act theory lacks a detailed focus on what actually happens in language as interaction (provided by conversation analysis). On the basis of the apology data scrutinised in the thesis, I propose a set of felicity conditions for the speech act of apology (chapter 2) and discuss how the apology (and speech acts broadly) should be considered as prototype entities (chapter 8). I show that when apologising for actions which they have committed, politicians are more fulsome in their apologies than we are in everyday conversation. I also show that they use more explicit apology tokens than is found in quotidian talk (chapter 3). When apologising for historical wrongs, I demonstrate that apologising is a backgrounded act and the focus of the statement is on being clear and unequivocal about the nature of the offences for which the government is apologising (chapter 6). I also argue that political apologies in interactive settings are best thought of as action chains (Pomerantz, 1978). That is to say, apologies in these environments may elicit a response from an interlocutor, but do not need to (chapters 4 & 5). This is quite unlike everyday talk (cf Robinson, 2004). I discuss how apology tokens may be used in the performance of other acts, including introducing dissent and undertaking serious face threat. I suggest that this comes about because apology tokens exist on a cline of pragmaticalisation (chapter 7).
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Testing featural and holistic composite technologies under different methods of face recallPrag, Bhavesh January 2005 (has links)
This thesis evaluates the effectiveness of two facial composite systems, used to produce facial images of alleged perpretators of crime, under varying conditions in two experiments. The first system is called E-face, a configural eigenfaced-based system originally developed at the University of Cape Town and currently undergoing further revisions; the second is called Faces, a featural system currently being used by several law enforcement agencies around the world.
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A Distributed System Interface for a Flight SimulatorZeitoun, Omar 11 1900 (has links)
The importance of flight training has been realized since the inception of manned flight. In this thesis, a project about the interfacing of hardware cockpit instruments with a flight simulation software over a distributed system is to be described. A TRC472 Flight Cockpit was to be used while linked with Presagis FlightSIM to fully simulate a Cessna 172 Skyhawk aircraft. The TRC 472 contains flight input gauges (Airspeed Indicator, RPM indicator... etc.), pilot control devices (Rudder, Yoke...etc.) and navigation systems (VOR,ADF...etc.) all connected to computer through separate USBs and identified as HID's (Human Interface Devices). These devices required real-time interaction with FlightSIM software; in total 21 devices communicating at the same time. The TRC472 Flight Cockpit and the FlightSIM software were to be running on a distributed system of computers and to be communicating together through Ethernet. Serialization was to be used for the data transfer across the connection link so objects can be reproduced seamlessly on the different computers. Some of the TRC472 devices were straight forward in writing and reading from, but some of them required some calibrations of raw I/O data and buffers. The project also required making plugins to overwrite and extend FlightSIM software to communicate with the TRC472 Flight Cockpit. The final product is to be a full fledged flight experience with complete environment and physics of the Cessna 172. / Thesis / Master of Applied Science (MASc)
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Highly deformed rotational bands and normal deformed high spin structures in p171 and sHFZhang, Yanci 03 May 2008 (has links)
Potential energy surface calculations have predicted the existence of the island of triaxial strongly deformed (TSD) nuclei with N~94 and Z~72. Subsequent calculations indicated that 164,166Hf would be the most favorable even-even nuclei in the island region for finding low-lying TSD structures. But experimental discoveries of TSD bands only have been reported in 161 C163,164,165 C167Lu nuclei with the wobbling mode, a unique signature of nuclei with stable triaxiality. And experimental investigation of Hf nuclei performed with Euroball and Gammasphere produced negative results on the two Hf isotopes. Later investigations in 168Hf and 173,174,175Hf show existence of strongly-deformed bands, but none has been confirmed as TSD structures. These results motivated an extension of the search for TSD bands in the region to heavier Hf-isotopes like 171,172Hf. A Gammasphere experiment was carried out to search for triaxial strongly deformed (TSD) structures in 171,172Hf. Three strongly deformed bands in 172Hf and one in 171Hf were identified through 48Ca (128Te, xn) reactions. Linking transitions were established for the band in 171Hf and, consequently, its excitation energies and spins (up to 111/2 ) were firmly established. However, none of the 172Hf sequences was linked to known structures. Experimental evidence of triaxiality was not observed in these bands. The new bands are compared with other known strongly deformed bands in neighboring Hf isotopes. Theoretical investigations within cranked-shell models and Cranked Relativistic Mean-Field (CRMF) Calculations have been performed. Cranking calculations with the Ultimate Cranker code suggest that the band in 171Hf and two previously proposed TSD candidates in 170Hf and 175Hf are built upon proton (i13/2h9/2) configurations, associated with near-prolate shapes and deformations enhanced with respect to the normal deformed bands. Cranked relativistic meanield calculations suggest that band 2 in 175Hf has most likely a near-prolate superdeformed shape involving the high-j intruder orbitals. It is quite likely that the bands in 172Hf are similar in character to this band. In this experiment six normal deformed bands in 171Hf and five in 172Hf were identified, also known low spin structures have been extended considerably. Linking transitions to known low spin structures were well established for these five bands of 171Hf but none of 172Hf. The spin and parity determinations of these rotational bands have been performed based on DCO ratio and intensity measurement. The suggested configurations of these structures also have been proposed.
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Nickel Extraction From Gordes Laterites By Hydrochloric Acid LeachingGoveli, Ahmet 01 September 2006 (has links) (PDF)
Leaching is the most widely used process for extraction of nickel metal from lateritic ores.
In this study, nickel extraction from Manisa-Gö / rdes region laterites by hydrochloric acid leaching is aimed. The mineralogical analysis of sample showed that hematite, goethite, dolomite, quartz and smectite are the main minerals in the ore. Attrition scrubbing, cycloning and magnetic separation with permroll were used as preconcentration processes but results were unsatisfactory. HCl leaching experiments were conducted both at room temperature and at elevated temperatures. The effects of various parameters such as leaching duration, particle size, concentration of HCl, pulp density, Cl- concentration and temperature on nickel recovery were examined. The results showed that under the optimised leaching conditions (particle size: 100 % -1 mm, HCl concentration: 3 N, leaching duration: 3 hours, leaching temperature: 100 oC, pulp density: 1/30 solid to liquid ratio by volume) it was possible to extract 87.26 % of nickel in the ore.
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Optimization Of Conditions Of Metallothermic Reduction Of Rare Earth PreconcentratesYilmaz, Serkan 01 January 2007 (has links) (PDF)
Rare earth ferrosilicon alloy is an important additive for ferrous metallurgy. It is mainly used to control the detrimental effects of sulfur in steel and to modify graphite structures in cast iron. The aim of this study was to optimize the conditions for the production of rare earth ferrosilicon alloy by metallothermic reduction process using a preconcentrate prepared from a bastnasite type of ore present in the Beylikahir-EskiSehir region of Turkey.
In this study, the rare earth preconcentrate was reduced by aluminum together with ferrosilicon and rare earth ferrosilicon alloys were produced. The optimum conditions of reduction, which are time, temperature, reducer amounts and the basicity of the slag phase, were investigated by smelting in an induction furnace. At the end of the study, a rare earth ferrosilicon alloy containing 39.3 % rare earths,
37.5 % silicon, 19.3 % iron and 3.9 % aluminum was produced under the optimum conditions determined with 57.7 % rare earth metal recovery.
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Investigation Of Cadmium Removal Mechanisms By ClinoptiloliteIpci, Irem 01 December 2009 (has links) (PDF)
Clinoptilolite is a natural zeolite which can be used favorably in heavy metal removal. The main mechanisms for metal removal via clinoptilolite are adsorption and ion exchange. Several sources propose to keep the normality constant to obtain equilibrium isotherms for ion exchange systems, while many studies use constant sorbent mass with varying normalities of the sorbate. The objective of this study is to investigate the prevailing mechanisms of clinoptilolite during cadmium removal and the impact of the methodology for obtaining equilibrium isotherms.
Batch Cd2+ removal experiments were conducted by using the two different methodologies (i.e. keeping the sorbent mass constant vs. keeping the normality constant) with clinoptilolite in as-received (AsC) and conditioned form (CnC), an ion exchange resin and granulated activated carbon. Exchangeable and framework cations, conductivity and pH were monitored during experiments. The equilibrium results were then fitted to isotherm models.
The prevailing mechanisms for Cd2+ removal with clinoptilolite are discussed considering all monitored parameters and isotherm model fits. Use of the methodology was seen to have an effect on the overall Cd2+-clinoptilolite interaction. For example, differences between methodologies are observed regarding maximum sorbed Cd2+ and the distribution of exchangeable cations. Conductivity profiles provided a good indication of presence of ion exchange and demonstrated that it is more dominating for CnC than for AsC. The Cd2+ removal capacities observed in this study (0.65 meq/g for AsC and 1.46 meq/g for CnC) are the highest recorded for a clinoptilolite sample, as can be found in the literature.
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Development Of Acetylcholinesterase Biosensor For The Detection Of PesticidesKavruk, Murat 01 September 2010 (has links) (PDF)
Pesticides are natural or artificial molecules aimed to kill, or mitigate any harmful organism. Although their use in agriculture provides us with an increased crop yield, remains of chemicals on the products creates health concerns in society. Organophosphates and carbamates are two groups of insecticides. Although they are far more lethal against insects and small animals, they can also cause poisoning in humans through the inhibition of acetylcholinesterase enzyme (AChE) that plays an important role in human nervous system. Therefore, the detection of these compounds is crucial. The conventional methods for the detection of these compounds are expensive, time-consuming and need expertise. In this study, a fast, disposable, cheap and accurate acetylcholinesterase biosensor was developed to detect organophosphate and carbamate-based pesticide residues. By means of adsorption method, AChE, the chromophore 5,5' / -Dithio-bis(2-nitrobenzoic acid) (DTNB) and artificial substrate acetylthiocholine (ATCh) were immobilized on the supporting material. In optimization studies / from 3 to 15U/mL concentrations were experimented for AChE, 1 to 5mM DTNB and 1 to 5mM ATCh concentration gradients were used.
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As a result of the optimization studies 12U/mL ACHE concentration, 5mM DTNB concentration and 5mM ATCh concentration were determined for constructing a pesticide biosensor.
Detection limit of malathion, an organophosphate-based insecticide was found as 2.5ppm in 5% methanol solution. The biosensor conserved its integrity between pH 4 and 8, and gave false positive results after pH 10. Stability studies showed that, biosensor retained its activity for at least 60 days at 4° / C to discrimnate between positive and negative controls.
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Hydrothermal Method For Doping Of Zinc Oxide Nanowires And Fabrication Of Ultraviolet PhotodetectorsAfal, Aysegul 01 July 2012 (has links) (PDF)
Nanotechnology comprises of the understanding and control of materials and processes at the nanoscale. Among various nanostructured materials, semiconducting nanowires attract much interest for their novel physical properties and potential device applications. The unique properties of these nanowires are based on their high surface to volume ratio and quantum confinement effect.
Zinc oxide, having a direct, wide bandgap and large exciton binding energy, is highly appealing for optoelectronic devices. Due to excellent optical and electrical properties, zinc oxide nanowires have been utilized to fabricate various devices such as solar cells, light emitting diodes, transistors and photodetectors. Furthermore, zinc oxide, in its natural state exhibits n-type conductivity. Addition of impurities often
leads to remarkable changes in their electrical and optical properties, which open up new application areas.
Among the many synthesis methods for zinc oxide nanowires, hydrothermal method is an attractive one due to its easy procedure, simple equipment and low temperature requirements.
In this thesis, zinc oxide nanowires were grown and doped by hydrothermal method. Different metal dopants such as copper, silver and aluminum were used for this purpose. These metals were selected as dopants due to their effect on magnetic properties, p-type conduction and electrical conductivity of ZnO nanowires, respectively. Doped nanowires were fully characterized and the changes in their physical properties were investigated.
In addition, hydrothermally synthesized pure and aluminum doped zinc oxide nanowires were used as the electrically active components in ultraviolet photodetectors. Silver nanowires were utilized as transparent electrodes. Optoelectronic properties of the detectors were examined. Effect of in-situ annealing and nanowire length was investigated. Short recovery time, around 4 seconds, with a decent on/off ratio of 2600 was obtained. This design provides a simple and cost effective approach for the fabrication of high performance ultraviolet photodetectors.
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