Showing items 161 - 180 of 190

Your selections:

Sideroxylon inerme - White Milkwood

- Skead, C J (Cuthbert John)

Sideroxylon inerme - White Milkwood

- Skead, C J (Cuthbert John)

Some properties of a model F1 layer of the ionosphere

- De Jager, Gerhard

  • Authors: De Jager, Gerhard
  • Date: 1963
  • Subjects: Ionosphere , Ionospheric electron density
  • Language: English
  • Type: Thesis , Masters , MSc
  • Identifier: vital:5515 , http://hdl.handle.net/10962/d1011046 , Ionosphere , Ionospheric electron density
  • Description: The present work was initially aimed at providing an explanation for some of the phenomena that occur in the ionosphere at sunrise. The approach that was taken was to determine the changes that take place on a theoretical model of the ionosphere and then to compare these with observations. A prerequisite for this approach was a theoretical model that would show, among other things, a bifurcation of the F layer during daytime without making unjustified arbitrary assumptions. The absence of such a model, particularly as far as non-equilibrium conditions are concerned, resulted in the present attempt to provide such a model for the F1 region.
  • Full Text:
  • Date Issued: 1963

Studies on certain aspects of the neuromuscular physiology of insects

- Moran, V. C. (V. Cliff)

  • Authors: Moran, V. C. (V. Cliff)
  • Date: 1963
  • Subjects: Insects -- Physiology
  • Language: English
  • Type: Thesis , Masters , MSc
  • Identifier: vital:5866 , http://hdl.handle.net/10962/d1012879
  • Description: It is well known that high potassium ion concentrations depolarize nervous tissue and it has been suggested that the nerve sheath surrounding the peripheral nerves of insects serves as a protective barrier for the exclusion of potassium ions, in the haemolymph, from the immediate environment of axons. Further it is known that the concentration of potassium ions in the haemolymph of phytophagous insects is far higher than that in predatory forms; this has led to the suggestion that the nerve sheath in plant feeding insects should be more highly developed than that of entomophagous insects. In this work the structure of the nerve sheath in phytophagous and predatory insects has been studied and this assumption has been shown to be groundles. However, preliminary experiments on the effects of ions and drugs on the peripheral nerves of phytophagous and predatory insects have shown that there is a definite difference in susceptibility between the nerves of these two forms and this has led to the postulate of a diffusion barrier beneath the level of the nerve sheath, which is more highly developed in phytophagous than in predatory forms. The properties of this second barrier are discussed. Part 1. , During the course of the work which has been described in Part 1- an outbreak of large saturniid moths Nudaurelia cytherea capensis Stoll.) occurred in the Grahamstown area. It was felt that an investigation into the properties of the flight motor of this moth, which has an extremely low wing beat frquency, might be rewarding as our knowledge of the flight motor in insects is limited to those with very much higher wing beat frequencies than that of this moth. The anatomy, innervation and histology of the flight muscles of Nudaurelia are described and it is shown that the flight motor of this moth is functionally different to that of other insects which have been investigated. Further, Nudaurelia shows a characteristic warm-up fluttering of the wings prior to flight - this phenomenon has also been examined in the following investigation. This study has yielded information about the location of a warm-up centre in the central nervous system of this moth. Part 2.
  • Full Text:
  • Date Issued: 1963

Studies on the behaviour of unfed blue tick larvae (Boophilus decoloratus)

- Goldsmid, John Marsden

  • Authors: Goldsmid, John Marsden
  • Date: 1963
  • Subjects: Boophilus -- South Africa , Ticks -- Behavior -- South Africa , Ticks -- Physiology -- South Africa
  • Language: English
  • Type: Thesis , Masters , MSc
  • Identifier: vital:5852 , http://hdl.handle.net/10962/d1012044 , Boophilus -- South Africa , Ticks -- Behavior -- South Africa , Ticks -- Physiology -- South Africa
  • Description: Ticks "are not merely annoying pests but surpass all other anthropods in the number and variety of disease agents for which they are carriers (Chandler 1955). This statement is certainly true of Boophilus decoloratus (Koch), the blue tick, which is probably one of the most important ticks in South Africa. Various studies have been made on the blue tick in Africa, among which are investigations on taxonomy (Hoogstraal 1956); distribution (Theiler 1949 and 1962); ecology (Kraft 1961); disease transmission (Neitz and du Toit 1938; du Toit 1947; Neitz 1956 a and b); control and resistance to insecticides (du Toit, Graf and Bekker 1941; Whitnall and Bradford 1947; Whitehead 1958 and 1959) To date, the behaviour of Boophilus decoloratus has not been studied to any extent. The aim of the present work is to analyse the behaviour of the unfed larvae into its constituent patterns in order to determine what are the significant environmental factors which affect this behaviour. It is also hoped that the present laboratory studies might help in understanding their behaviour in the field. Intro., p. 1.
  • Full Text:
  • Date Issued: 1963

Studies on the emulsion scouring of raw wool

- Grové, Christo Carel

  • Authors: Grové, Christo Carel
  • Date: 1963
  • Subjects: Woolen and worsted manufacture
  • Language: English
  • Type: Thesis , Masters , MSc
  • Identifier: vital:4479 , http://hdl.handle.net/10962/d1012100 , Woolen and worsted manufacture
  • Description: Knowledge of the mechanism of detergency under various conditions has thus far been built up from laboratory studies. It is well known that the laboratory methods for determing detergency are on the whole not able to give results which agree with those obtained in practice, probably because the actual scouring conditions cannot be duplicated exactly in the laboratory. Detergency testing on a full industrial scale is virtually impossible in view of the high cost and the production losses involved. In commercial raw wool scouring, which is an extremely complex system, it would be very difficult to exercise proper and complete control. The study described here was carried out on a specially constructed pilot plant which is similar to a fullscale plant in that the lengths of the bowls are of the same order as those of industrial plants, but they are considerably narrower. The trials were carried out under strictly controlled conditions in which the effects to be studied were created by the necessary changes while all other factors were kept constant, The pilot plant experiments were planned from indications of laboratory studies and the results were expected to be more comparable with those obtained in industrial practice, The effect of several factors on the scouring of raw wool was studied from the detergent efficiency aspect. The factors investigated were: mechanical action, backflow, temperature and detergency builders. A number of detergents which were selected from the large range which is available were compared with regard to efficiency and economy of scouring. A difficulty which hinders quantitative laboratory work on nonionic detergents is the fact that there is no rapid, accurate method for the estimation of nonionic detergents. The analytical methods which are employed at present are interfered with by virtually all the impurities which are normally present in scouring liquors. Some of the existing methods have been investigated and tested for precision and reproducibility and an attempt was made at establishing a new method. The sorption of nonionic detergents by various substrates has not been fully investigated because of the above reason and also because the amounts of detergent sorbed by most substrates are very small and difficult to determine. Attempts were made at determining the sorption of nonionic detergents onto wool and impurities which are normally found in scouring liquors. A new method for the investigation of "inactivation" of detergent by contaminants present in scouring liquors, which may be regarded as an indirect indication of detergent sorption, was investigated.
  • Full Text:
  • Date Issued: 1963

Tabarireve woende

- Tabarirevu Muyambo, Tracey, Hugh

Tata wawu osi wana

- Emmelina Zavala, Chopi women, Tracey, Hugh

The crystal structure of caesium permanganate by x-ray diffraction

- Nassimbeni, L R

  • Authors: Nassimbeni, L R
  • Date: 1963
  • Subjects: Permanganates -- Crystallography , X-rays -- Diffraction , Crystals -- Piezoelectricity , Pyroelectricity
  • Language: English
  • Type: Thesis , Masters , MSc
  • Identifier: vital:4484 , http://hdl.handle.net/10962/d1012942
  • Description: The crystal structure of caesium permanganate has been determined. CsMn0₄ crystallises in the orthorhombic space group Pnma. There are four molecules per unit cell with a = 10.0692 Å, b = 5.8080 Å, c = 7.9470 Å. The structure was determined by Fourier syntheses on the (010) and (001) projections and refined by two-dimensional difference syntheses. The structure is similar to that of KMn0₄. The manganese is surrounded by four oxygen atoms at an average distance of 1.629 Å arranged in a slightly distorted tetrahedron. The caesium is surrounded by eight manganese atoms at an average distance of 4.381 Å.
  • Full Text:
  • Date Issued: 1963

The design and construction of a recording spectrometer for the measurement of fluorescence excitation spectra in the vacuum ultra-violet region

- Davidson, A T

  • Authors: Davidson, A T
  • Date: 1963
  • Language: English
  • Type: Thesis , Masters , MSc
  • Identifier: vital:21177 , http://hdl.handle.net/10962/6761
  • Description: Summary: A recording spectrometer for the measurement of fluorescence excitation spectra in the visible and ultra-violet regions of the spectrum is described. A direct method of modulating the hydrogen light source of the spectrograph is presented, whereby the discharge is driven by an A.C. power oscillator. The use of tuned amplifiers in the detecting unit is investigated as a means of eliminating the D.C. component of the dark current. Aspects of the modulation method are discussed. Fluorescence and energy transfer in aromatic hydrocarbon is discussed with particular regard to anthracene. Some absorption, fluorescence, excitation and reflection spectra of anthracene obtained by previous workers are presented9 together with Tables listing the wavelengths of principal maxima for the above spectra published in the literature. Features of the excitation spectrum of anthracene are discussed and are related to its absorption and fluorescence spectra. The role of surface effects, defects and impurities are discussed in relation to the fluorescence of anthracene. The method of A.C. detection was unable to resolve the excitation spectrum of anthracene due to the high noise level associated with the method. However, peaks in the ultra-violet region of the hydrogen molecular spectrum were recorded at a modulation frequency of 400 Kc/sec. The noise level is explained and ways of improving the signal to noise ratio of the A.C. detection system are suggested. It is concluded that D.C. detection is a simpler and more direct way of measuring excitation spectra. No modulated signals were detected when the hydrogen discharge was excited at 6·5 Mc/sec. Signals were recorded at modulation frequencies of 400 Kc/sec . The degree of modulation at 400 Kc/sec. increased with decrease in the pressure of the hydrogen discharge.
  • Full Text:
  • Date Issued: 1963

The development of a method for the determination of microgram amounts of magnesium by atomic absorption

- Taylor, John Douglas

  • Authors: Taylor, John Douglas
  • Date: 1963
  • Subjects: Atomic absorption spectroscopy -- Instruments , Magnesium
  • Language: English
  • Type: Thesis , Masters , MSc
  • Identifier: vital:4507 , http://hdl.handle.net/10962/d1013344
  • Description: This thesis includes a description of modifications of the Hilger atomic absorption apparatus, which was used for most of the work. These modifications were restricted to the atomiser and burner, which were replaced by a modified "Eel" flame. photometer atomiser-burner and resulted in improved sensitivity and instrumental stability for the atomic absorption of magnesium. A comparison of the performance of this unit with that of the unmodified Hilger apparatus is given. A "Handigas" butane-propane mixture)-air flame was used for most of this work, but a coal-gas-air flame was also studied and found to give slightly greater sensitivity. The method was found to be subject to interference from many elements. Strontium salts, employed as releasing agents to overcome the effect of other elements, were not completely effective as milligram amounts of several elements interfered even when strontium was present. Among the more serious interfering elements are: aluminium, iron, manganese and zirconium (less than 20 p.p.m. interfere); the alkali and alkaline earth metal salts (more than 200-500 p.p.m. interfere); phosphate (more than 100 p.p.m. P₂0₅ uranium (more than 4,000 p.p.m.); arsenate and vanadate. An attempt is made to explain the mechanism of some of these interfering effects. A combination of strontium salt and acetyl acetone was found to over-come the effects of small amounts of several elements that form complexes with acetyl acetone (e.g. iron and aluminium) far more effectively than strontium alone. Larger amounts of many interfering elements are removed by a solvent extraction procedure employing acetyl acetone and chloroform. Elements which cannot be removed by this means may be separated by anion-exchange, volatilisation, electrolysis or precipitation. A spiking technique, which compensates JT/GB for the effects of small amounts of interfering elements, is described and enables many samples to be analysed without prior separations. The method described has good sensitivity (the limit of determination is approximately 1 microgram of magnesium in 50 ml. of solution). It has been applied to the analysis of clay samples, iron ore, limestone and uranium metal, oxides and processing solutions. The coefficient of variation of the method was determined using two clay samples and results of 2.0 and 4.6 percent, at magnesium oxide concentrations of 0.65 and 0.22 percent respectively, wore obtained. The speed of the method compares favourably with others described for the determination of microgram amounts of magnesium, but increases if large amounts of interfering elements are present.
  • Full Text:
  • Date Issued: 1963

The High Corner, Mom's funeral, 1963

The influence of temperature in the ecology of the intermediate host snails of Schistosoma and Fasciola (Trematoda) in southern Rhodesia

- Shiff, Clive Julian

  • Authors: Shiff, Clive Julian
  • Date: 1963
  • Subjects: Schistosoma , Schistosomiasis , Fasciola , Snails -- Zimbabwe , Trematoda
  • Language: English
  • Type: Thesis , Doctoral , PhD
  • Identifier: vital:5881 , http://hdl.handle.net/10962/d1013208
  • Description: The influence of temperature on the bionomics of Bulinus (Physopsis) globosus, Biomphalaria pfeifferi and Lymnaea natalensis has been studied both in the laboratory under controlled conditions and in the field under normal seasonal influences. Field studies were carried out in two different localities, one a semi-permanent pond and the other a temporary waterbody. For this purpose a sampling implement was developed. The results show the seasonal progression of these populations both with respect to estimated numbers and the size distribution of the snails. The rate of actual increase at different seasons was calculated for the three species where the data were sufficient. In the laboratory the snails were maintained at various temperatures, other conditions being kept standard. Daily records of mortality and fecundity of various cohorts reared from the egg stage enabled the compilation of life tables fof the speciesand from these data were calcualted the intrinsic rate of natural increase and other parameters. Effects of crowding in aquaria were studied. From the data obtained in the laboratory it was possible to predict the distribution and population potential for each species for snail of various environmental conditions. These predictions were, in fact, confirmed by field observation.
  • Full Text:
  • Date Issued: 1963

The Ngodo of Regulo Mavila

- Shambini, Tracey, Hugh

The place of geometry in university mathematics : inaugural lecture delivered at Rhodes University

- Cruise, S E

  • Authors: Cruise, S E
  • Date: 1963
  • Language: English
  • Type: Text
  • Identifier: vital:612 , http://hdl.handle.net/10962/d1020681
  • Description: Inaugural lecture delivered at Rhodes University. , Rhodes University Libraries (Digitisation)
  • Full Text:
  • Date Issued: 1963

The role of the artist in society as seen in the novels of Henry James

- Middleton, D F

  • Authors: Middleton, D F
  • Date: 1963
  • Subjects: James, Henry, 1843-1916 , Journalists as artists , Art and society , Fiction -- History and criticism -- 19th century
  • Language: English
  • Type: Thesis , Masters , MA
  • Identifier: vital:2305 , http://hdl.handle.net/10962/d1012874
  • Description: Henry James (1843-1916) is a curious and, by his own choice, enigmatic figure. We have a great many dates, a few letters, and little else. James's fragment of autobiography, vast as it is; is strangely unrevealing. There is a wealth of impressions as one would expect from such a writer but precious little about the man. Henry James was chary of describing his personal feelings - so much so that some doubted his ability to have any strong emotions. His autobiography, interesting as it is, is pure observation, memories of people, places and impressions, all marvellously sensitive, but little personal feeling. Intro., p. 1.
  • Full Text:
  • Date Issued: 1963

Title 1. Mogobo Title 2. Segata mosabani

- Mapulana men and women, Tracey, Hugh

  • Authors: Mapulana men and women , Tracey, Hugh
  • Date: 1963
  • Subjects: Folk music--Africa , Pedi (African people) , Folk music--South Africa , Field recordings , Africa, Sub-Saharan , Africa South Africa Bushbuck Ridge f-sa
  • Language: Pedi
  • Type: sound recordings , field recordings , sound recording-musical
  • Identifier: http://hdl.handle.net/10962/188011 , vital:44717 , International Library of African Music, Rhodes University, Grahamstown, South Africa , TR194-03
  • Description: The change over from Mogobo to Segata mosabani takes place at approximately 2m 19s from the start of the dance. The impression of general jollification, noise making, shouts and whistles is well caught in this recording. The Mapulana clan of the Pedi consider themselves a distinctive group and have occupied the territories below the Drankensburg Mountain, in the vicinity of Bushbuck Ridge for several generations. A few people of Tsonga (Shangaan) orign have settled among them. "Come and dance on the sand. We dance on the sand with praises." Two initiation dances with beaten sticks, Bushbuck horn (-11.01-), Kudu horn (-11.01-), 3 drums (-14.01101-) and whistle
  • Full Text: false
  • Date Issued: 1963

Tlisa kgopa

- Mashego, Barney (Chief), Pedi women and one old man, Tracey, Hugh

Tsa lla molapong

- Mashego, Barney (Chief), Four Pedi women, Tracey, Hugh

  • Authors: Mashego, Barney (Chief) , Four Pedi women , Tracey, Hugh
  • Date: 1963
  • Subjects: Folk music--Africa , Pedi (African people) , Folk music--South Africa , Field recordings , Africa, Sub-Saharan , Africa South Africa Bushbuck Ridge f-sa
  • Language: Pedi
  • Type: sound recordings , field recordings , sound recording-musical
  • Identifier: http://hdl.handle.net/10962/188704 , vital:44778 , International Library of African Music, Rhodes University, Grahamstown, South Africa , TR195-04
  • Description: This district is plagued, they say, by men who come home from employment eleswhere, eat the food of their relatives until it is all finished without doing a stroke of work to help, and then disappear from pastures new, leaving their families starving. The fourth woman stood by and added cries of encouragement. "They cry, they cry at the river. They hear legaletlwa (a tree)." The thorn tree has twisted boughs which are inclined to rub against each other amd emit occassional creaking sounds. Pounding song with mortar and three pestles
  • Full Text: false
  • Date Issued: 1963

Tsepe mpolaye

- Small group of Pedi women with hoes, Four Pedi women, Tracey, Hugh

  • Disclaimer
  • Privacy
  • Copyright
  • Contact