Resumo: Assim como o gráfico de"XBARRA", o gráfico T2 de Hotelling é lento na detecção de pequenas a moderadas pertubações no processo. Estudos consagrados mostram que o desempenho do gráfico de "XBARRA" melhora em muito com o uso da amostragem dupla. Com base nestes resultados, este trabalho se dedica ao estudo das propriedades dos gráficos T2 com amostragem dupla para processos bivariados. Através de uma rotação dos eixos cartesianos é possível transformar as variáveis originais, que em geral são altamente correlacionadas, em variáveis independentes. Com as novas variáveis e trabalhando com coordenadas polares foi possível obter o número médio de amostras (NMA) que o gráfico proposto necessita para detectar uma alteração no processo. Por meio de comparações dos NMAs foi possível verificar que o gráfico de controle proposto é, na maioria das vezes, mais eficiente que os gráficos adaptativos em que o tamanho das amostras e/ou o intervalo entre retirada de amostras são variáveis. / Abstract: Similarly to the X chart, the T2 chart is slow to detect small or even moderate process disturbances. Earlier studies have shown that the use of the double sampling procedure improves substabtially the X chart performance. Based on that, we propose here to study the performance of the T2 chart with double sampling applied to control bivariate processes. An appropriate rotation transforms the original bivariate variables, in general presenting high correlation, in independent variables. With these equivalent variables and working with polar coordinates, it was possible to obtain the average run length (ARL) that measures the effectiveness of the proposed chart in detecting a process change. By comparisons of ARLs it was possible to verify that the proposed control chart is, frequently, more efficient than the adaptive charts with variable sample size or variable sampling interval. / Orientador: Antonio Fernando Branco Costa / Coorientador: Fernando Augusto Silva Marins / Banca: Messias Borges Silva / Banca: Sebastião de Amorim / Mestre

abstract: This final research paper provides both a performer's perspective and a recording of double clarinet literature by William O. Smith (b. 1926), Eric Mandat (b. 1957), and Jody Rockmaker (b. 1961). The document includes musical examples, references to the recording, and interviews with the composers. The first chapter contains a brief literature review of sources on world double clarinets, biographies of the above-mentioned composers, and other pertinent information. Chapters 2-4 include the performer's perspective on the following works: Epitaphs for Double Clarinet by William O. Smith, Double Life for Solo Clarinet by Eric Mandat, and two compositions by Jody Rockmaker, Half and Half for demi-clarinet in A, and Double Dip. The final chapter examines how double clarinet music has evolved, the challenges and limitations of the repertoire, and the future of the double clarinet genre. / Dissertation/Thesis / D.M.A. Music 2013

Submitted in fulfilment of the academic requirements for the Degree of Master's in Chemistry, Durban University of Technology, 2017. / Hydrotalcites (HT) and hydrotalcites-like (HTLc) compounds were synthesized by the co-precipitation method under low supersaturation. The synthesized binary Mg-Al hydrotalcites and ternary Cu/Mg-Al hydrotalcite-like compounds were characterized by various physico-chemical techniques such as inductively coupled plasma-optical emission spectroscopy (ICP-OES), powder X-ray diffraction (XRD), Fourier transform- infrared spectroscopy (FT-IR), ultraviolet-visible (UV-VIS) spectroscopy, thermogravimetric analysis (TGA), scanning electron microscopy (SEM) and BET surface area analysis. Elemental composition generated from ICP-OES data revealed a value of x in the region of 0.25 to 0.33 for all the compounds except for the MgAl-11 sample which revealed an x value of 0.5 while XRD patterns exhibited characteristic features indicative of an ordered layered material. FT-IR spectra confirmed the presence of characteristic functional groups and interlayer anions. Only Cu2+ which has a d9 configuration was accountable for the bands identified in UV-VIS spectra, whereas both Mg and Al with their d0 electron configurations showed no absorptive bands in the UV-VIS spectra. During thermal treatment by TGA, typical weight loss of Cu-Mg/Al HTLcs with temperature elevation was observed. The SEM images clearly demonstrated that all the Cu-Mg/Al HTLcs retained their characteristically layered structure morphologies. The BET surface area measurements showed no trend, however the surface area decreased with an increase in the copper concentration in some cases. For the heterogeneous hydroxylation of phenol using H2O2 as an oxidant, several reaction parameters such as solvent systems, catalyst amount, temperature, substrate/oxidant ratio, time and solvent volume were investigated. The product stream, monitored by gas chromatography showed that catechol (CAT) and hydroquinone (HQ) were the main products. Non-catalytic (blank) experiments were investigated to determine whether the reactants and the internal standard contributes to the conversion of phenol without the use of a catalyst. All blank reactions showed very low phenol conversions which were less than 1%, whereas the Mg/Al HTs showed low phenol conversions as well. All the Cu-Mg/Al catalysts showed measurable phenol conversion with Cu-Mg/Al-51a giving the highest conversion of 29.9% and a 56 and 44% selectivity towards CAT and HQ, respectively. The Cu-Mg/Al-15b catalyst, which had the lowest copper concentration, showed the lowest phenol conversion of 8.3% with a 55 % CAT selectivity and 45% HQ selectivity. In general, the phenol conversion increased with an increase in copper concentration. This reinforced the hypothesis that copper was the active centre in this reaction, since no measurable conversion was observed with Mg/Al HTs. / M

No description available.

During the Second World War, more than 22,000 Japanese Canadians were interned to various locations throughout Canada. While more than 60 years have passed since these events, there remains limited research on the impact that this event had on this group of people. Using McCubbin and Patterson’s (1983) Double ABCX model of family stress and adaptation as a framework, this study used historical narratives of 69 Japanese Canadians to gain insight into a) how Japanese Canadians coped with the challenges associated with their internment, and b) what resources they used during this same time period. The analysis of the coping strategies was done using a modified version of existing measures of coping strategies (Folkman, Lazarus, Dunkel-Schetter, DeLongis, & Gruen, 1986; Suedfeld, Krell, Wiebe, & Steel, 1997), and the analysis of resources was done using an adjusted version of Rettig’s (1995) and Tucker and Rice’s (1985) resource classification list. There were no statistically significant differences between Japanese Canadian men and women in their coping strategy use, but that there were differences between the Issei (first generation) and Nisei (second generation). The Issei used Self Control, Positive Reappraisal, and Denail more than the Nisei, while the Nisei used Seeking Social Support more than the Issei. A strong relationship between coping and resources was found; a relationship that has often been assumed, but never tested. The findings from this study also provided additional support for the usefulness of using both narratives and the Double ABCX model in research. / Arts, Faculty of / Social Work, School of / Graduate

The majority of empirical literature on refugee identity and homeland attachment focuses on single exile trajectories: one migratory movement out of the homeland and possibly repatriation. It largely neglects more complex experiences of exile and their implications. Double-exile, a second fleeing of one’s homeland after repatriation, adds complexity to our conventional understanding of refugee perceptions of home and identity. This study explores double-exile experiences of the Rwandan Hutu refugee population of Dzaleka refugee camp to examine its impacts on notions of home and identity construction. This ethnographic study found that the Rwandan Hutu refugees have a unique relationship to home and identity. Double-exile ended their sense of belonging to Rwandan society. Thus causing a break in the conventional longing for home and deterritorializing their identity. These impacts are apparent through the juxtaposition of study participants’ notions of home and their experiences of return and double-exile, a lack of connection or desire to return to Rwanda, and an absence of pride in their Rwandan identity and cultural practices. These findings suggest that more importance must be placed on the role of pre-flight experience of refugees as an integral element to their construction of notions of home. It also indicates that, contrary to more conventional exile trajectories where refugee identity is derived from a historical consciousness, double-exile refugees construct identity through a present-focus.

The results of a long term monitoring program on the massive X-ray binary Cygnus X-1, whose constituents are believed to consist of a normal 0 star primary and a black hole companion, are presented. Spectra of this system were collected between 1980 and 1984 using a Reticon detector. The resulting absorption line radial velocity (RV) curve is characteristic of a single line spectroscopic binary. These velocities were combined with those available in the literature to determine an orbital period of 5.59977 ± 0.00001 days. A P/P ≃ 10⁻⁵ day⁻¹ was found from analysis of all available velocity measures. This change in the period is larger than that expected as a result of mass loss from the primary or from- models of the system in which large mass transfer rates occur between the components. A fit of the orbital motion of the primary to the RV curve gives a K = 75.0 ± 1 km/s and no significant eccentricity. The vsini of the primary was found, using the fourier transform technique, to be 94.3 km/sec. This is substantially smaller than the literature value of vsini = 140 km/sec. The value of the K and vsini allow the ratio mp/mx to be determined as ≃ 2.0 . The equivalent width of Hƴ allows the absolute magnitude of the primary to be estimated at -6.5 ± 0.2 . A comparison of the spectrum of the primary to those of an array of standards allows the spectral type to be given as between 09.5 and 09.7 I . This spectral type is consistent that the primary is a normal star of mass ≃ 20 M⊙. The mass of the secondary is therefore 10 ± 3 Mʘ. Measurement of the interstellar lines to obtain an independent E(B-V) reveals that the interstellar line strength per unit E(B-V) is lower than in any other direction in the sky. Stars for which velocity-excitation slopes and mass loss estimates, from UV line profile modeling and/or radio free-free emission measures, are available in the literature were collated. An empirical fit to this material allowed the mass loss rate for HDE 226868 (the primary of Cygnus X-1) to be estimated at 5.7 ± 2 x 10⁻⁶ M/year. The He II λ4686 and Hɑ lines are found in emission. After removal of the contribution to the line profile from the primary the radial velocity curve of the residual He II λ4686 line is found to have small scatter from a smooth fit ( ± 10 km/sec ) with no significant eccentricity. No sizeable variation in the K amplitude at different epochs was found contrary to a previous investigation and the origin of the emission is thus apparently fixed and stable. A phase lag of 130° is measured between the absorption and emission velocity curves and thus the simple interpretation of the emmision originating near the secondary can not be correct. The He II emission equivalent width, corrected for the underlying primary absorption, shows strong modulation (30%) over the 5.6 day orbital period. This variation is probably the result of the profile of the primary varying with which face of the star is directed towards the observer. During two separate observing sessions in 1982 the He II equivalent widths were found to be 40% and 15% larger than the mean of all other observations while still showing the same variation with orbital phase. Such a change has been seen once before and may be associated with transitions to the X-ray high state. The Hƴ and Hβ lines show a 20% variation on the 294 day X-ray period in the sense of largest equvalent widths at X-ray minimum ( 0 phase ). The Balmer lines are a composite of an absorption component from the primary and a weak emission component. This is best explained by variations in the outflow from the star, which is the source of both the emission component and the X-ray flux via accretion. Such variations may be the result of pulsation of the primary. The Hɑ line profile has been decomposed into three components; the absorption component from the primary, emission from a shell with an inner radius 1.4 times that of the primary, arid a component with properties similar to the He II λ4686 line. The great width of the Hɑ line, previously explained as being the result of rotation of the disc, is instead shown to be the result of superposition of these components. The origin of the He II λ4686 emission is explained by assuming that a stellar wind enhanced in the direction of the secondary is completely ionized within a volume surrounding the secondary. The He II between the edge of this volume and the surface of the primary is enhanced as a result of X-ray heating and ionization. Model profiles appear in reasonable agreement with high dispersion spectra. The obvious explanation for the orbital variation in the He II line is that X-ray heating of the side of the primary facing the secondary produces a change in the effective temperature. Calculation of the size of this effect reveals that it is too small to explain the changes observed. X-ray observations made with EXOSAT with excellent time resolution allowed timing of the X-ray absorption features seen near orbital phase zero. Simultaneous X-ray spectra allowed an estimate of their column density as 2.0 x 1023 cm⁻². Two scale lengths of dips were found of 10⁸ and 10¹¹ cm. These values are in good agreement with theoretical predictions for the sizes of inhomogeneties in high mass loss stellar winds. The location of the material producing the absorption dips was calculated as being ≃ 4-8 R⊙ from the X-ray source. / Science, Faculty of / Physics and Astronomy, Department of / Graduate

The technique of electron-nuclear double resonance spectroscopy (ENDOR) has been used to determine the identity and structure of radicals trapped in x-irradiated single crystals of cytosine monohydrate and caffeine hydrochloride dihydrate. The radical studied in cytosine mono-hydrate had previously been observed by several workers using electron paramagnetic resonance (EPR) but its identity was in question. All intramolecular and several intermolecular proton hyperfine couplings were analyzed in detail. The experimentally determined coupling parameters were compared with ones obtained by theoretical means for several possible radical species. The agreement between the observed and calculated parameters fit best for the radical formed by net addition of a hydrogen atom to 0(2) of cytosine, with the hydroxyl proton lying in the nodal plane of the π-system. The appearance of twice the number of certain ENDOR lines than expected from the crystal symmetry was interpreted by postulating that the radical was stabilized in two different conformations at 77°K. The assignment of the hyperfine couplings to specific protons was supported by an ENDOR study of a partially deuterated cytosine monohydrate crystal, grown from heavy water. Three different radical species were identified in caffeine hydrochloride dihydrate x-irradiated at room temperature. The EPR spectrum of this system, which had not previously been reported, was too complex to be analyzed. Furthermore, the EPR spectra of two of the radicals studied by ENDOR could not be distinguished in the overall EPR lineshape. One of these radicals had a lifetime of only a few hours and was tentatively identified as the methyl radical, primarily on the basis of the observed isotropic proton hyerpfine coupling constant of -62.65 MHz. The other radical was indefinitely stable and was identified as that formed by net abstraction of a hydrogen atom from N(9) of the caffeine moiety. This radical is equivalent to that which would be produced by the loss of an electron from a neutral caffeine molecule, the caffeine cation; as such, it is the first reported cation radical in a purine derivative. The radical which dominated the EPR spectrum was identified as that resulting from net addition of a hydrogen atom to C(8) of the protonated caffeine molecule. The identification of this radical was based on the analysis of four different proton hyperfine couplings. Nitrogen (¹⁴N) hyperfine and quadrupole coupling tensors were also obtained from the ENDOR spectra and were attributed to N(7). The observation of ¹⁴N-ENDOR lines, which had not previously been reported in any pyrimidine or purine derivative, provided a second, independent estimate of the unpaired spin density centred on N(7). An indirect second-order effect, giving rise to a non-crossing phenomenon, was observed between the methylene protons, which were also found to be non-equivalent. The structure of this radical was found to agree with those determined previously by EPR and by molecular orbital calculations for the analogous species in other purine derivatives. / Science, Faculty of / Chemistry, Department of / Graduate

Until Serge Prokofiev’s 1924 ballet score Trapèze, the double bass occupied a background or at best a doubling role in almost all composers’ use of the instrument. Technical challenge was limited in these pieces, because composers did not see the instrument’s potential in a chamber music environment. As luthiers developed the instrument, the technical ability of players grew, and composers began writing more challenging music for the instrument. As one of the first major composers to see the double bass in a new light, Prokofiev wrote challenging music for the instrument. This paper illuminates the alluring pedagogical aspects of Prokofiev's Quintet in G Minor, Op. 39 and provides recommendations for accomplishing some difficult passages with ease.

The notation of t/i numbers is used to describe knots and links on the double torus in two different ways, as a step toward the eventual classification of double-torus links.