An investigation into the spelling ability of English-speaking and Afrikaans-speaking pupils in South African schools
- Authors: Hayward, Fritz Reitz
- Date: 1963
- Subjects: English language -- Orthography and spelling -- Study and teaching , Afrikaans language -- Orthography and spelling -- Study and teaching
- Language: English
- Type: Thesis , Masters , MEd
- Identifier: vital:1972 , http://hdl.handle.net/10962/d1012238 , English language -- Orthography and spelling -- Study and teaching , Afrikaans language -- Orthography and spelling -- Study and teaching
- Description: The parlous state in which the English language finds itself in South Africa, both in its written and speech forms, is the cause ot grave concern to most English-speaking citizens, and to many Afrikaans-speaking people as well. This is the case not only in the commercial world and the civll service, but also in the schools and universities, and in fact in most walks of life. Although we are conscious of this state of affairs, and can quote many examples of the poor quality of English used, we have no measuring device through which we can assess exactly how bad the language used by any given group of people is. It is not possible to compare the performance in English of a certain school with standard English and to express the result as a percentage score. The aim of this investigation was to find out how well, or how badly, South African school children spell, and to compare the performances of English- and Afrikaansspeaking pupils. It was felt that the results would provide some concrete evidence and fairly accurate data which could be used to assess the standard of English spelling in our schools, and to pinpoint some of the major weaknesses. The writer hoped, thus, that the investigation might be of some practical usefulness to teachers of English spelling, and as spelling is basic to the written word and to some extent to the spoken word, it might make some small contribution to the drive towards better English in South African schools.
- Full Text:
- Date Issued: 1963
- Authors: Hayward, Fritz Reitz
- Date: 1963
- Subjects: English language -- Orthography and spelling -- Study and teaching , Afrikaans language -- Orthography and spelling -- Study and teaching
- Language: English
- Type: Thesis , Masters , MEd
- Identifier: vital:1972 , http://hdl.handle.net/10962/d1012238 , English language -- Orthography and spelling -- Study and teaching , Afrikaans language -- Orthography and spelling -- Study and teaching
- Description: The parlous state in which the English language finds itself in South Africa, both in its written and speech forms, is the cause ot grave concern to most English-speaking citizens, and to many Afrikaans-speaking people as well. This is the case not only in the commercial world and the civll service, but also in the schools and universities, and in fact in most walks of life. Although we are conscious of this state of affairs, and can quote many examples of the poor quality of English used, we have no measuring device through which we can assess exactly how bad the language used by any given group of people is. It is not possible to compare the performance in English of a certain school with standard English and to express the result as a percentage score. The aim of this investigation was to find out how well, or how badly, South African school children spell, and to compare the performances of English- and Afrikaansspeaking pupils. It was felt that the results would provide some concrete evidence and fairly accurate data which could be used to assess the standard of English spelling in our schools, and to pinpoint some of the major weaknesses. The writer hoped, thus, that the investigation might be of some practical usefulness to teachers of English spelling, and as spelling is basic to the written word and to some extent to the spoken word, it might make some small contribution to the drive towards better English in South African schools.
- Full Text:
- Date Issued: 1963
An investigation of the radio emission by the planet Jupiter on 18 Mc/s & 22 Mc/s
- Authors: Gruber, Georg Maria
- Date: 1963
- Subjects: Radio astronomy , Jupiter (Planet) -- Observations , Radio sources (Astronomy)
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: vital:5524 , http://hdl.handle.net/10962/d1012113 , Radio astronomy , Jupiter (Planet) -- Observations , Radio sources (Astronomy)
- Description: This thesis describes the investigation carried out of the radio noise emitted by the planet Jupiter on 18 Mc/s and 22 Mc/s. Chapter I gives a brief introduction and outlines radioastronomical as well as astronomical ideas concerning Jupiter. A detailed survey of the research done to date including some of the hypotheses formulated by previous workers is presented in Chapter II . Chapter III deals with the apparatus used in this research. Two similar sets of apparatus were used. The aerials were folded dipoles. The signals were fed to the receiver, an R 206 , via a 300 ohm impedance line. To increase the gain an extra I -F. stage was included. This gave a gain of better than a 120 dB. To match the signals into the recorder a cathode follower was used. The operating procedure appears in the fourth chapter. The results obtained are discussed and tabulated at the end of the chapter. They agree with the findings made by previous workers, within the experimental limit. Histograms of the occurrence probability versus the revised System III coordinates are presented for each frequency and compared to previous ones. The final chapter contains the author ' s interpretation of the observed effects. A model based on a radiation analogous to the Cerenkov effect is found to be not inconsistent with the available data . Ending the chapter suggestions for further research are made.
- Full Text:
- Date Issued: 1963
- Authors: Gruber, Georg Maria
- Date: 1963
- Subjects: Radio astronomy , Jupiter (Planet) -- Observations , Radio sources (Astronomy)
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: vital:5524 , http://hdl.handle.net/10962/d1012113 , Radio astronomy , Jupiter (Planet) -- Observations , Radio sources (Astronomy)
- Description: This thesis describes the investigation carried out of the radio noise emitted by the planet Jupiter on 18 Mc/s and 22 Mc/s. Chapter I gives a brief introduction and outlines radioastronomical as well as astronomical ideas concerning Jupiter. A detailed survey of the research done to date including some of the hypotheses formulated by previous workers is presented in Chapter II . Chapter III deals with the apparatus used in this research. Two similar sets of apparatus were used. The aerials were folded dipoles. The signals were fed to the receiver, an R 206 , via a 300 ohm impedance line. To increase the gain an extra I -F. stage was included. This gave a gain of better than a 120 dB. To match the signals into the recorder a cathode follower was used. The operating procedure appears in the fourth chapter. The results obtained are discussed and tabulated at the end of the chapter. They agree with the findings made by previous workers, within the experimental limit. Histograms of the occurrence probability versus the revised System III coordinates are presented for each frequency and compared to previous ones. The final chapter contains the author ' s interpretation of the observed effects. A model based on a radiation analogous to the Cerenkov effect is found to be not inconsistent with the available data . Ending the chapter suggestions for further research are made.
- Full Text:
- Date Issued: 1963
An x-ray investigation of the thermal decomposition of unirradiated and irradiated silver permanganate.
- Authors: Woods, Geoffrey Steward
- Date: 1963
- Subjects: Decomposition (Chemistry) , Materials -- Thermal properties , Solids -- Thermal properties , Permanganates , Silver compounds
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: vital:4511 , http://hdl.handle.net/10962/d1013450
- Description: [From Introduction] The first step in the study of the thermal decompositions of solids is an examination of the kinetics, since this casts much light on the mechanism of the reaction. It must be borne in mind, however, that a theoretical expression, derived on the basis of a particular mechanism, even if it fits the observed experimental results, is not conclusive proof of the validity of the mechanism when applied to the decomposition under examination.
- Full Text:
- Date Issued: 1963
- Authors: Woods, Geoffrey Steward
- Date: 1963
- Subjects: Decomposition (Chemistry) , Materials -- Thermal properties , Solids -- Thermal properties , Permanganates , Silver compounds
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: vital:4511 , http://hdl.handle.net/10962/d1013450
- Description: [From Introduction] The first step in the study of the thermal decompositions of solids is an examination of the kinetics, since this casts much light on the mechanism of the reaction. It must be borne in mind, however, that a theoretical expression, derived on the basis of a particular mechanism, even if it fits the observed experimental results, is not conclusive proof of the validity of the mechanism when applied to the decomposition under examination.
- Full Text:
- Date Issued: 1963
Aspects of form and style in Beethoven's string quartets
- Authors: Biesheuvel, Barbara
- Date: 1963
- Subjects: Beethoven, Ludwig van, 1770-1827 -- Quartets -- strings
- Language: English
- Type: Thesis , Masters , MMus
- Identifier: vital:2678 , http://hdl.handle.net/10962/d1007645
- Description: Many books have been written which deal with the subject of form and style in Beethoven's works. Most writers, however, seem to be satisfied with superficial descriptions - in some cases merely programatic - which do not explain the underlying problems and treatment of form. Furthermore, no book exists, to my knowledge, which delves so deeply and with such detail as to deduce with almost certain accuracy the inner coherency of the form. It is the aim of this analysis to approach the problem in this way. The edition used for this purpose is that one published by Ernst Eulenberg Ltd. London WI, which was edited from the autograph M.S. by Professor Dr. Wilhelm Altman. No comparisons are made with other editions, and possible printer's and other errors are not considered. I chose the works to be studied here, the three quartets Op. 59, for two reasons: 1) the string quartet medium is one of the most suitable types of instrumental music for the study of form, 2) the Op. 59 quartets belong to a period in Beethoven's life when he was particularly intent upon experimentation in form and development of dimension.
- Full Text:
- Date Issued: 1963
- Authors: Biesheuvel, Barbara
- Date: 1963
- Subjects: Beethoven, Ludwig van, 1770-1827 -- Quartets -- strings
- Language: English
- Type: Thesis , Masters , MMus
- Identifier: vital:2678 , http://hdl.handle.net/10962/d1007645
- Description: Many books have been written which deal with the subject of form and style in Beethoven's works. Most writers, however, seem to be satisfied with superficial descriptions - in some cases merely programatic - which do not explain the underlying problems and treatment of form. Furthermore, no book exists, to my knowledge, which delves so deeply and with such detail as to deduce with almost certain accuracy the inner coherency of the form. It is the aim of this analysis to approach the problem in this way. The edition used for this purpose is that one published by Ernst Eulenberg Ltd. London WI, which was edited from the autograph M.S. by Professor Dr. Wilhelm Altman. No comparisons are made with other editions, and possible printer's and other errors are not considered. I chose the works to be studied here, the three quartets Op. 59, for two reasons: 1) the string quartet medium is one of the most suitable types of instrumental music for the study of form, 2) the Op. 59 quartets belong to a period in Beethoven's life when he was particularly intent upon experimentation in form and development of dimension.
- Full Text:
- Date Issued: 1963
Contributions to our knowledge of the biology of Machiloides Delanyi Wygodzinsky and Ctenolepisma Longicaudata Escherich : (Hexapoda Thysanura)
- Authors: Heeg, J. (Jan)
- Date: 1963
- Subjects: Insects -- Adaptation , Insects -- Physiology , Thysanura , Apterygota
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: vital:5856 , http://hdl.handle.net/10962/d1012261 , Insects -- Adaptation , Insects -- Physiology , Thysanura , Apterygota
- Description: Among the South African Thysanura, the order Lepismatoidea has spread over the whole sub-continent, while all except one species of the order Machiloidea are confined to the discontinuous forest belt which lies below the escarpment of the inland plateau. The Machiloidea are not , however, strictly confined to the actual forests within their geographical region, some species invading regions of considerable aridity. Investigations on the ecology, water relations and orientation behaviour of a representative species of each order have been carried out. These have revealed that: (i) the physical conditions in the typical niche of the Machiloidea are extremely stable, whereas those in the habitat of the Lepismatoidea are subject to some considerable fluctuation. (ii) the Lepismatoidea are more resistant to desiccation than the Machiloidea; in both cases this resistance is due in part to physical barriers in the cuticle and partly to an active metabolic process. (iii) the Machiloidea rely on their eversible vesicles, situated on the abdominal coxosternites, for the uptake of water which cannot be drunk, such as a thin film of water or soil capillary water. (iv) the Lepismatoidea are able to absorb water from a subsaturated atmosphere. (v) the behavioural responses of both in respect of humidity, temperature, light and gravity, are such as to keep them in conditions within the range of their physiological limitations. From these results it is concluded that the Machiloidea can survive outside the shelter of forests, provided that water is readily available in some form in which it can be absorbed by the animals. The general implications of the results are such as to permit the erection of an hypothesis explaining the distribution of the Thysanura in South Africa in terms of t he availability of wate. The results also lead to speculations on the evolution of the Pterygota.
- Full Text:
- Date Issued: 1963
- Authors: Heeg, J. (Jan)
- Date: 1963
- Subjects: Insects -- Adaptation , Insects -- Physiology , Thysanura , Apterygota
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: vital:5856 , http://hdl.handle.net/10962/d1012261 , Insects -- Adaptation , Insects -- Physiology , Thysanura , Apterygota
- Description: Among the South African Thysanura, the order Lepismatoidea has spread over the whole sub-continent, while all except one species of the order Machiloidea are confined to the discontinuous forest belt which lies below the escarpment of the inland plateau. The Machiloidea are not , however, strictly confined to the actual forests within their geographical region, some species invading regions of considerable aridity. Investigations on the ecology, water relations and orientation behaviour of a representative species of each order have been carried out. These have revealed that: (i) the physical conditions in the typical niche of the Machiloidea are extremely stable, whereas those in the habitat of the Lepismatoidea are subject to some considerable fluctuation. (ii) the Lepismatoidea are more resistant to desiccation than the Machiloidea; in both cases this resistance is due in part to physical barriers in the cuticle and partly to an active metabolic process. (iii) the Machiloidea rely on their eversible vesicles, situated on the abdominal coxosternites, for the uptake of water which cannot be drunk, such as a thin film of water or soil capillary water. (iv) the Lepismatoidea are able to absorb water from a subsaturated atmosphere. (v) the behavioural responses of both in respect of humidity, temperature, light and gravity, are such as to keep them in conditions within the range of their physiological limitations. From these results it is concluded that the Machiloidea can survive outside the shelter of forests, provided that water is readily available in some form in which it can be absorbed by the animals. The general implications of the results are such as to permit the erection of an hypothesis explaining the distribution of the Thysanura in South Africa in terms of t he availability of wate. The results also lead to speculations on the evolution of the Pterygota.
- Full Text:
- Date Issued: 1963
On the physiology of the lantern retractor muscle of Parechinus angulosus
- Authors: Boltt, R E
- Date: 1963
- Subjects: Echinodermata -- Physiology
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: vital:5900 , http://hdl.handle.net/10962/d1013513
- Description: From Resumé: The lantern retractor muscles of regular echinoids act in almost isometric conditions and a study of their control was considered to be of interest. The retractor muscles cannot be indirectly stimulated from the radial nerves, but proved to be very photosensitive. Their responses to light were therefore studied. The muscles show a complex pattern of contraction in response to illumination, which includes both excitatory and inhibitory components. The possible genesis of these patterns is discussed and examined in the light of the responses of the muscles to direct current stimulation and to drugs. It is concluded that many of the features of the response are undoubtedly neurogenic in origin, but that myogenic activity may possibly also be involved.
- Full Text:
- Date Issued: 1963
- Authors: Boltt, R E
- Date: 1963
- Subjects: Echinodermata -- Physiology
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: vital:5900 , http://hdl.handle.net/10962/d1013513
- Description: From Resumé: The lantern retractor muscles of regular echinoids act in almost isometric conditions and a study of their control was considered to be of interest. The retractor muscles cannot be indirectly stimulated from the radial nerves, but proved to be very photosensitive. Their responses to light were therefore studied. The muscles show a complex pattern of contraction in response to illumination, which includes both excitatory and inhibitory components. The possible genesis of these patterns is discussed and examined in the light of the responses of the muscles to direct current stimulation and to drugs. It is concluded that many of the features of the response are undoubtedly neurogenic in origin, but that myogenic activity may possibly also be involved.
- Full Text:
- Date Issued: 1963
Poësie in 'n Grensland-situasie : verkenning van die ontwikkeling van 'n tema en 'n houding in die Afrikaanse digkuns
- Authors: Vorster, Jo-Anne
- Date: 1963
- Subjects: Afrikaans poetry -- History and criticism
- Language: Afrikaans
- Type: Thesis , Masters , MA
- Identifier: vital:3638 , http://hdl.handle.net/10962/d1013452
- Description: From Introduction. In hierdie studie word 'n poging aangewend om 'n sekere aspek van, en 'n sekere ontwikkeling binne die Afrikaanse Poesie toe te lig. Onder Afrikaanse Poësie verstaan ons enige digwerk in Afrikaans, sy dit epies, liries of dramaties. Omdat ons o.m. belangstel in 'n sekere ontwikkeling, is ons uiteraard op 'n chronologiese indeling aangewys. Verskeie faktore (geskiedenis, kwaliteit van digwerk of gebrek aan kwaliteit, ens.) het daartoe bygedra dat ons in die Afrikaanse Poësie vyf groot periodes het wat vrywel onbestrede aanvaar word: die tydperk van die Genootskappers (vóór 1900); die tydperk van die Driemanskap (tussen 1900 en 1920); die insinking van die twintigerjare (1920 tot 1934); die vernuwing van Dertig (1934 tot 1945); die jongste tydperk (tot 1962). Hierdie algemeen aanvaarde indeling dien ons doel. Dit is egter noodsaaklik om dit onomwonde te stel dat die geesteshouding van die digter, soos ons dit uit die gedig leer ken, van groter belang is by ons studie as die ontstaansdatum van die gedig.
- Full Text:
- Date Issued: 1963
- Authors: Vorster, Jo-Anne
- Date: 1963
- Subjects: Afrikaans poetry -- History and criticism
- Language: Afrikaans
- Type: Thesis , Masters , MA
- Identifier: vital:3638 , http://hdl.handle.net/10962/d1013452
- Description: From Introduction. In hierdie studie word 'n poging aangewend om 'n sekere aspek van, en 'n sekere ontwikkeling binne die Afrikaanse Poesie toe te lig. Onder Afrikaanse Poësie verstaan ons enige digwerk in Afrikaans, sy dit epies, liries of dramaties. Omdat ons o.m. belangstel in 'n sekere ontwikkeling, is ons uiteraard op 'n chronologiese indeling aangewys. Verskeie faktore (geskiedenis, kwaliteit van digwerk of gebrek aan kwaliteit, ens.) het daartoe bygedra dat ons in die Afrikaanse Poësie vyf groot periodes het wat vrywel onbestrede aanvaar word: die tydperk van die Genootskappers (vóór 1900); die tydperk van die Driemanskap (tussen 1900 en 1920); die insinking van die twintigerjare (1920 tot 1934); die vernuwing van Dertig (1934 tot 1945); die jongste tydperk (tot 1962). Hierdie algemeen aanvaarde indeling dien ons doel. Dit is egter noodsaaklik om dit onomwonde te stel dat die geesteshouding van die digter, soos ons dit uit die gedig leer ken, van groter belang is by ons studie as die ontstaansdatum van die gedig.
- Full Text:
- Date Issued: 1963
Roman-waarheid en roman-fiksie: 'n ondersoek na die waarheidsgehalte van sekere Afrikaanse aktualiteitsromans en na die waarheidsmaatstaf in die aktualiteitsromankritiek
- Authors: Mulock-Houwer, F A M
- Date: 1963
- Subjects: Afrikaans fiction -- History and criticism
- Language: Afrikaans
- Type: Thesis , Masters , MA
- Identifier: vital:3633 , http://hdl.handle.net/10962/d1012910
- Description: Dit het my herhaaldelik getref dat, by die beoordeling van bepaalde tipes Afrikaanse romans, deur die kritici sekere maatstawwe aangelê word wat as artistieke of literêre kriteria nie geldig, nie ter sake nie, en daarom meestal ook ontoelaatbaar is. Ek bedoel meer bepaaldelik die historiese en aktualiteitsromans: genres wat hul tematiese materiaal grotendeels betrek uit die verbye of hedendaagse "werklikheid" van die gemeenskap waartoe, in prakties alle gevalle, én die auteurs én die kritici van daardie romans behoort. Die ongeldige, slegs ten dele geldige of verkeerd gebruikte geldige kriteria vind hul oorsprong in 'n foutiewe vereenselwiging van die letterkundige kriterium "waarheid in die roman" met die aktualiteitsmaatstawwe "objektiewe werklikheid" en "oordeel oor hierdie werklikheid wat in die roman gevel word". 'n Ondersoek na die grondbeginsels van die romankritiek, die mate van ooreenkoms wat die Afrikaaner kritiek daarmee vertoon, en dus ook na die "waarheidsgehalte" van die betrokke romans self, vorm die opset van hierdie verhandeling. In die loop van die ondersoek het dit egter spoedig geblyk dat die onderwerp te wyd was, en dat dit die beste beperk kon word deur te konsentreer op 'n kleiner aantal romans binne een genre. Die keuse het geval op die aktualiteitsroman, en meer bepaaldelik op 'n negetal romans i.v.m. die "nie-blanke aktualiteit" en "rasseverhoudings in Suid-Afrika". Hierdie keuse is gedoen om twee hoofredes. Eerstens omdat die rasseprobleem veral sedert die Tweede Wêreldoorlog en meer bepaaldelik sedert die Atlantiese Oorkonde (1942) dié heersende wêreldprobleem geword het. Die rassebeleid in Suid-Afrika is derhalwe skerp in die lig gestel, met die gevolg dat Suid-Afrikaners daartoe gedryf is om hulle houding nie net in die praktyk te handhaaf nie, maar ook teoretiee en godsdienstig te verdedig. As aktualiteitsprobleem is die rassesituasie dus die interessantste en dié wat die meeste opspraak wek. Die tweede rede vir my keuae is die feit dat die kritieke oor die "romans oor rasseverhoudings", juis weens die aktualiteitstweedrag oor hierdie situasie, die volledigste voorbeeld vorm van die heersende "werklikheid"/"waarheid"-verwarring in die Afrikaanse aktualiteitsroman-kritiek. Die skripsie is in drie hoofdele verdeel: ʹn ondersoek na die waarheidemaatstaf in die kritiek, toepassing van hierdie maatstaf op romans oor die naturel en op die kritieke daaroor, en die verdere uitwerking daarvan i.v.m. romans oor die kleurling. Die nege romans wat ter sprake gebring is, mag beskou word as die noemenewaardigste kuns-en-aktualiteitspogings in hul genre, en tewens as 'n volledige aanduiding van die algemene ontwikkelingsgang van daardie genre. Die gekose volgorde van die romans dien dan ook om twee hooffaktore te omlyn: (a) die ontwikkeling van die aktualiteitsiening vanuit die idilliese plaasverband van Franz se romans, via die beperkte siening van die nie-blanke stadsproblematiek, na ʹn paging tot 'n volledige Suid-Afrikaanse probleemstelling in Rabie se Ons, die Afgod, en (b) die kunsgehalte van die betrokke romans en die mate waarin dit die draagkrag van die tendens beinvloed, en wederom die mate waarin die keuse van die tema en tendens die waarheidsgehal teen draagkrag van die romans as aktualiteitskommentare bepaal. Ons het gevolglik die romans oor die naturel, wat die eerste fase van die aktualiteitsiening behandel, in Deel II geplaas, en die romans oor die kleurling, van die staanspoor af meer problematies van aard, en as groep dié wat die mees gevorderde aktualiteitsiening vertoon in Deel III. Die slotbeskouing is ʹn kort samevatting van die mate van ontwikkeling in die Afrikaanse aktualiteitsroman oor die nie-blanke, en 'n vasstelling van die aard van die werklikheiq/waarheid-digotomie in die kritieke daaromtrent.
- Full Text:
- Date Issued: 1963
- Authors: Mulock-Houwer, F A M
- Date: 1963
- Subjects: Afrikaans fiction -- History and criticism
- Language: Afrikaans
- Type: Thesis , Masters , MA
- Identifier: vital:3633 , http://hdl.handle.net/10962/d1012910
- Description: Dit het my herhaaldelik getref dat, by die beoordeling van bepaalde tipes Afrikaanse romans, deur die kritici sekere maatstawwe aangelê word wat as artistieke of literêre kriteria nie geldig, nie ter sake nie, en daarom meestal ook ontoelaatbaar is. Ek bedoel meer bepaaldelik die historiese en aktualiteitsromans: genres wat hul tematiese materiaal grotendeels betrek uit die verbye of hedendaagse "werklikheid" van die gemeenskap waartoe, in prakties alle gevalle, én die auteurs én die kritici van daardie romans behoort. Die ongeldige, slegs ten dele geldige of verkeerd gebruikte geldige kriteria vind hul oorsprong in 'n foutiewe vereenselwiging van die letterkundige kriterium "waarheid in die roman" met die aktualiteitsmaatstawwe "objektiewe werklikheid" en "oordeel oor hierdie werklikheid wat in die roman gevel word". 'n Ondersoek na die grondbeginsels van die romankritiek, die mate van ooreenkoms wat die Afrikaaner kritiek daarmee vertoon, en dus ook na die "waarheidsgehalte" van die betrokke romans self, vorm die opset van hierdie verhandeling. In die loop van die ondersoek het dit egter spoedig geblyk dat die onderwerp te wyd was, en dat dit die beste beperk kon word deur te konsentreer op 'n kleiner aantal romans binne een genre. Die keuse het geval op die aktualiteitsroman, en meer bepaaldelik op 'n negetal romans i.v.m. die "nie-blanke aktualiteit" en "rasseverhoudings in Suid-Afrika". Hierdie keuse is gedoen om twee hoofredes. Eerstens omdat die rasseprobleem veral sedert die Tweede Wêreldoorlog en meer bepaaldelik sedert die Atlantiese Oorkonde (1942) dié heersende wêreldprobleem geword het. Die rassebeleid in Suid-Afrika is derhalwe skerp in die lig gestel, met die gevolg dat Suid-Afrikaners daartoe gedryf is om hulle houding nie net in die praktyk te handhaaf nie, maar ook teoretiee en godsdienstig te verdedig. As aktualiteitsprobleem is die rassesituasie dus die interessantste en dié wat die meeste opspraak wek. Die tweede rede vir my keuae is die feit dat die kritieke oor die "romans oor rasseverhoudings", juis weens die aktualiteitstweedrag oor hierdie situasie, die volledigste voorbeeld vorm van die heersende "werklikheid"/"waarheid"-verwarring in die Afrikaanse aktualiteitsroman-kritiek. Die skripsie is in drie hoofdele verdeel: ʹn ondersoek na die waarheidemaatstaf in die kritiek, toepassing van hierdie maatstaf op romans oor die naturel en op die kritieke daaroor, en die verdere uitwerking daarvan i.v.m. romans oor die kleurling. Die nege romans wat ter sprake gebring is, mag beskou word as die noemenewaardigste kuns-en-aktualiteitspogings in hul genre, en tewens as 'n volledige aanduiding van die algemene ontwikkelingsgang van daardie genre. Die gekose volgorde van die romans dien dan ook om twee hooffaktore te omlyn: (a) die ontwikkeling van die aktualiteitsiening vanuit die idilliese plaasverband van Franz se romans, via die beperkte siening van die nie-blanke stadsproblematiek, na ʹn paging tot 'n volledige Suid-Afrikaanse probleemstelling in Rabie se Ons, die Afgod, en (b) die kunsgehalte van die betrokke romans en die mate waarin dit die draagkrag van die tendens beinvloed, en wederom die mate waarin die keuse van die tema en tendens die waarheidsgehal teen draagkrag van die romans as aktualiteitskommentare bepaal. Ons het gevolglik die romans oor die naturel, wat die eerste fase van die aktualiteitsiening behandel, in Deel II geplaas, en die romans oor die kleurling, van die staanspoor af meer problematies van aard, en as groep dié wat die mees gevorderde aktualiteitsiening vertoon in Deel III. Die slotbeskouing is ʹn kort samevatting van die mate van ontwikkeling in die Afrikaanse aktualiteitsroman oor die nie-blanke, en 'n vasstelling van die aard van die werklikheiq/waarheid-digotomie in die kritieke daaromtrent.
- Full Text:
- Date Issued: 1963
Some properties of a model F1 layer of the ionosphere
- 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
- 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
- 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
- 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)
- 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
- 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
- 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
- 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
The crystal structure of caesium permanganate by x-ray diffraction
- 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
- 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
- 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
- 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
- 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
- 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 role of the artist in society as seen in the novels of Henry James
- 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
- 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
A comparative kinetic study of the reaction between chromium nitrate solutions and the carboxyl groups of acetate and collage
- Authors: Russell, Allan Edward
- Date: 1962
- Subjects: Chemical kinetics , Chromium , Spectrophotometry , Electrophoresis
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: vital:4493 , http://hdl.handle.net/10962/d1013101
- Description: The kinetics of the coordination reaction between the carboxyl group of the acetate radical and the trivalent chromium ion has been examined by independent methods at a temperature selected to yield reasonably accurate rate data. The study has been extended to an examination of the rate of chromium "fixation" by the carboxyl groups of hide collagen in a series of miniature tannages carried out under similar conditions for comparative purposes. The effect of olation of the chromium ions in solution on the kinetics of t he coordination reaction has also been examined. The rate of coordination of the acetate radical was followed by solvent extraction and spectrophotometric techniques over a range of concentration and pH levels. The rate data revealed a reaction having typical mass-action characteristics, the rate of reaction depending on the concentration levels of the chromium ion and the ionised acetate radical. An attempt made to distinguish a differential reaction rate in the case of a parallel reaction series using boiled and aged chromium nitrate reactant solutions, failed to reveal any significant differences between the series. The reactant solutions gave absorption spectra characteristic of the trivalent chromium ion with maxima in the 420 mµ and 570 mµ wavelength regions. The changes in optical density occurring in the vicinity of the maxima were followed spectrophotometrically, the height of the 570 mµ being found to increase during the course of reaction, while the height of the 420 mµ peak decreased. The variation in optical density at the 570 mµ peak was found to be directly related to the increase in concentration of the product complex in solution in accordance with the Baer-Bougher law, while the decrease in the height of the 420 mµ peak was related to the properties of unolated OH groups associated with the chromium complex as governed by pH and olation changes during the course of reaction. Boiled and aged chromium nitrate solutions gave reactant solutions having initial optical densities greater than those of the correspending fresh reactant solutions at the 570 mµ peak, and less than those of the fresh solutions at the 420 mµ peak. During the course of reaction, however, the two series converged to the same values. The equilibrium reaction solutions were subjected to paper electrophoretic study which indicated that all tho chromium was present in the form of cationic species. This finding was in accordance with stoicheiometric indications in the solvent extraction studies where coordination in a l : 1 ratio was reflected, giving rise to positively charged complex ions only. Making due allowance for band spreading the numbers of species predicted from the kinetic studies correspond with the electrophoretic patterns found. Application of the classical second order kinetic expression to the solvent extraction rate data, yielded plots having two distinctly linear sections, apparently indicating consecutive second order processes occurring in solution, contrary to the findings of previous workers who assign a first order mechanism to the reaction. This finding was consistent with the view that in the case of both the fresh and aged series, reaction consisted of successive coordination of an acetate radical to each chromium atom of a diol complex. Second order rate "constants" were calculated for each step and their dependency on pH level demonstrated. The findings of Hamm et al that these were first order reactions independent of acetate co'ncentration are believed to be due to their use of a large excess of acetate in their experiments. The kinetic study was further extended to an examination of the rate of "fixation"of trivalent chromium by the carboxyl groups of hide collagen under comparable conditions in a series of miniaturv tanning experiments in which the tannage substrate was provided in each of two physical forms:- (a) As hide powder where surface development was large, and (b) as prepared pelt pieces in which the fibrous weave pattern was retained. In view of the heterogeneity of the tannage systems, remarkable similarity was observed in the reaction course when compared with that of the acetate coordination studies, particularly in the case of the hide powder tannages. The dependency of the tannage rate data upon concentration and pH conditions was also found to be the same as in the case of the pure chemical system. The exact correlation between the rate data for the tannage and pure chemical systems was demonstrated by means of correlation plots. Close correlation was revealed in the case of hide powder tannage while the smaller degree of correlation observed in the case of the pelt tannage systems was attributed to the modifying effects of diffusion, particularly on the initial reaction velocity. The effect of using boiled and aged chromium solutions in the tannages was to increase the initial rate of chroniill!l "fixation" apparently due to tho coordination of a dial species at each coordination site. After the initial reaction period, the two series showed a tendency to converge as in the case of the spectrophotometric studies on the acetate reaction. The convergence trend was regarded as indicative of the tendency for the chromium in fresh solutions to under go rapid olation to the ame level as in the boiled and aged solutions. The experimental observations made on the various systems lead to the following conclusions:- (a) The mechanism of coordination of the acetate radical ttrivalent chromium appears to involve the successive coordination of ligand to each of the chromium atoms of a diol complex, both coordination steps proceeding by second order reaction mechanisms. (b) At the pH levels at which the reaction is carried out, the formation of elated bodios is rapid so that reaction in the case of both fresh and aged solutions essentially occurs between an elated species and the ionised acetate radical. (c) Modificati0ns in the absorption spectrum of the reactant solution at the 570 mµ peak are directly related to coordination, while changes at the 420 mµ peak are related to the formation of loosely-bound hydroxo chromium compounds, the concentrations of which depend on the pH level. (d) The mechanism of chromium fixation in hide is essentially similar to that operating in the case of coordination of the acetate radical to chromium, involving attachment of chromium to the side chain acid r sidues of collagen. (e ) The effect of olation is to enhance the rate of chromium fixation by hide protein during the initial reaction stages and to render possible bridge formation between adjacent side chains by secondary coordination during the latter reaction stages. (f) Where pelt pieces are used instead of hide powder, the initial rate of chromium fixation is dominated by the rate of diffusion of chromium into the fibrous structure. It should be stressed that the observations made on the various reaction systems cannot be regarded as exhaustive and the conclusions are subject to further confirmation. Consequently, the present study is essentially of a preliminary nature, but it is felt that the need for further investigation along similar lines has been demonstrated.
- Full Text:
- Date Issued: 1962
- Authors: Russell, Allan Edward
- Date: 1962
- Subjects: Chemical kinetics , Chromium , Spectrophotometry , Electrophoresis
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: vital:4493 , http://hdl.handle.net/10962/d1013101
- Description: The kinetics of the coordination reaction between the carboxyl group of the acetate radical and the trivalent chromium ion has been examined by independent methods at a temperature selected to yield reasonably accurate rate data. The study has been extended to an examination of the rate of chromium "fixation" by the carboxyl groups of hide collagen in a series of miniature tannages carried out under similar conditions for comparative purposes. The effect of olation of the chromium ions in solution on the kinetics of t he coordination reaction has also been examined. The rate of coordination of the acetate radical was followed by solvent extraction and spectrophotometric techniques over a range of concentration and pH levels. The rate data revealed a reaction having typical mass-action characteristics, the rate of reaction depending on the concentration levels of the chromium ion and the ionised acetate radical. An attempt made to distinguish a differential reaction rate in the case of a parallel reaction series using boiled and aged chromium nitrate reactant solutions, failed to reveal any significant differences between the series. The reactant solutions gave absorption spectra characteristic of the trivalent chromium ion with maxima in the 420 mµ and 570 mµ wavelength regions. The changes in optical density occurring in the vicinity of the maxima were followed spectrophotometrically, the height of the 570 mµ being found to increase during the course of reaction, while the height of the 420 mµ peak decreased. The variation in optical density at the 570 mµ peak was found to be directly related to the increase in concentration of the product complex in solution in accordance with the Baer-Bougher law, while the decrease in the height of the 420 mµ peak was related to the properties of unolated OH groups associated with the chromium complex as governed by pH and olation changes during the course of reaction. Boiled and aged chromium nitrate solutions gave reactant solutions having initial optical densities greater than those of the correspending fresh reactant solutions at the 570 mµ peak, and less than those of the fresh solutions at the 420 mµ peak. During the course of reaction, however, the two series converged to the same values. The equilibrium reaction solutions were subjected to paper electrophoretic study which indicated that all tho chromium was present in the form of cationic species. This finding was in accordance with stoicheiometric indications in the solvent extraction studies where coordination in a l : 1 ratio was reflected, giving rise to positively charged complex ions only. Making due allowance for band spreading the numbers of species predicted from the kinetic studies correspond with the electrophoretic patterns found. Application of the classical second order kinetic expression to the solvent extraction rate data, yielded plots having two distinctly linear sections, apparently indicating consecutive second order processes occurring in solution, contrary to the findings of previous workers who assign a first order mechanism to the reaction. This finding was consistent with the view that in the case of both the fresh and aged series, reaction consisted of successive coordination of an acetate radical to each chromium atom of a diol complex. Second order rate "constants" were calculated for each step and their dependency on pH level demonstrated. The findings of Hamm et al that these were first order reactions independent of acetate co'ncentration are believed to be due to their use of a large excess of acetate in their experiments. The kinetic study was further extended to an examination of the rate of "fixation"of trivalent chromium by the carboxyl groups of hide collagen under comparable conditions in a series of miniaturv tanning experiments in which the tannage substrate was provided in each of two physical forms:- (a) As hide powder where surface development was large, and (b) as prepared pelt pieces in which the fibrous weave pattern was retained. In view of the heterogeneity of the tannage systems, remarkable similarity was observed in the reaction course when compared with that of the acetate coordination studies, particularly in the case of the hide powder tannages. The dependency of the tannage rate data upon concentration and pH conditions was also found to be the same as in the case of the pure chemical system. The exact correlation between the rate data for the tannage and pure chemical systems was demonstrated by means of correlation plots. Close correlation was revealed in the case of hide powder tannage while the smaller degree of correlation observed in the case of the pelt tannage systems was attributed to the modifying effects of diffusion, particularly on the initial reaction velocity. The effect of using boiled and aged chromium solutions in the tannages was to increase the initial rate of chroniill!l "fixation" apparently due to tho coordination of a dial species at each coordination site. After the initial reaction period, the two series showed a tendency to converge as in the case of the spectrophotometric studies on the acetate reaction. The convergence trend was regarded as indicative of the tendency for the chromium in fresh solutions to under go rapid olation to the ame level as in the boiled and aged solutions. The experimental observations made on the various systems lead to the following conclusions:- (a) The mechanism of coordination of the acetate radical ttrivalent chromium appears to involve the successive coordination of ligand to each of the chromium atoms of a diol complex, both coordination steps proceeding by second order reaction mechanisms. (b) At the pH levels at which the reaction is carried out, the formation of elated bodios is rapid so that reaction in the case of both fresh and aged solutions essentially occurs between an elated species and the ionised acetate radical. (c) Modificati0ns in the absorption spectrum of the reactant solution at the 570 mµ peak are directly related to coordination, while changes at the 420 mµ peak are related to the formation of loosely-bound hydroxo chromium compounds, the concentrations of which depend on the pH level. (d) The mechanism of chromium fixation in hide is essentially similar to that operating in the case of coordination of the acetate radical to chromium, involving attachment of chromium to the side chain acid r sidues of collagen. (e ) The effect of olation is to enhance the rate of chromium fixation by hide protein during the initial reaction stages and to render possible bridge formation between adjacent side chains by secondary coordination during the latter reaction stages. (f) Where pelt pieces are used instead of hide powder, the initial rate of chromium fixation is dominated by the rate of diffusion of chromium into the fibrous structure. It should be stressed that the observations made on the various reaction systems cannot be regarded as exhaustive and the conclusions are subject to further confirmation. Consequently, the present study is essentially of a preliminary nature, but it is felt that the need for further investigation along similar lines has been demonstrated.
- Full Text:
- Date Issued: 1962
A study of South African aquatic Hyphomycetes
- Authors: Greathead, Sarah Kathleen
- Date: 1962
- Subjects: Hyphomycetes -- South Africa , Aquatic fungi -- South Africa
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: vital:4269 , http://hdl.handle.net/10962/d1014992
- Description: 1, Eighteen species of aquatic Hyphomycetes are recorded from South Africa for the first time. All except two of these can be assigned to described species. The other two are new species of Articulospora and Anguillospora and are described in this thesis. Three unidentified spore types, an "Articulospora" type and "Anguillospora" type and a Y-shaped spore are also described. 2. Spore development in ten species is described. 3. A key to the fungi described in this thesis is given. 4. General notes on the ecology of these fungi and a table recording the fungi found in the Eastern Cape Province of South Africa, their distribution within the localities and the nature of the material on which they are growing are given. 5. The gross characteristics of plate cultures of six species, five growing on malt agar, Czapek agar, plain agar and maize agar and one on malt agar only are described. 6. Growth of four species in liquid culture using the Czapek-Dox medium is reported. 7. The results of an investigation into the effect of variations in temperature and medium on the growth of plate cultures of five species are analysed, discussed and conclusions are drawn. 8. Growth of certain isolates of four species on twigs is described.
- Full Text:
- Date Issued: 1962
- Authors: Greathead, Sarah Kathleen
- Date: 1962
- Subjects: Hyphomycetes -- South Africa , Aquatic fungi -- South Africa
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: vital:4269 , http://hdl.handle.net/10962/d1014992
- Description: 1, Eighteen species of aquatic Hyphomycetes are recorded from South Africa for the first time. All except two of these can be assigned to described species. The other two are new species of Articulospora and Anguillospora and are described in this thesis. Three unidentified spore types, an "Articulospora" type and "Anguillospora" type and a Y-shaped spore are also described. 2. Spore development in ten species is described. 3. A key to the fungi described in this thesis is given. 4. General notes on the ecology of these fungi and a table recording the fungi found in the Eastern Cape Province of South Africa, their distribution within the localities and the nature of the material on which they are growing are given. 5. The gross characteristics of plate cultures of six species, five growing on malt agar, Czapek agar, plain agar and maize agar and one on malt agar only are described. 6. Growth of four species in liquid culture using the Czapek-Dox medium is reported. 7. The results of an investigation into the effect of variations in temperature and medium on the growth of plate cultures of five species are analysed, discussed and conclusions are drawn. 8. Growth of certain isolates of four species on twigs is described.
- Full Text:
- Date Issued: 1962
A theoretical investigation of the effects of solar eclipses on the ionosphere
- Walker, Anthony David Mortimer
- Authors: Walker, Anthony David Mortimer
- Date: 1962
- Subjects: Solar eclipses , Ionosphere , Solar activity
- Language: English
- Type: Thesis , MSc , Masters
- Identifier: vital:5550 , http://hdl.handle.net/10962/d1013467
- Description: The behaviour of the ionosphere during a solar eclipse is of great interest because radiation from the sun is the cause of ionization in the upper atmosphere and it is useful to be able to conduct experiments where this radiation is cut off and restored in a known manner. Experimental results, especially those dealing with the F2 layer, have proved puzzling. Cusps which cannot be explained appear on the records obtained from ionosphere sounders and in the F2 region the electron density at a given height shows a maximum after the eclipse where one would expect it simply to rise to a steady value. An attempt is made in this thesis to explain some of the anomalies in terms of tilts in the ionospheric layers and minima of electron density or "valleys" between the ionospheric layers. The problem is attacked theoretically. Part I deals with the theoretical background to ionospheric physics in general and to this problem in particular. Standard methods of dealing with radio propagation in the ionosphere as well as some methods developed by the author are discussed. Part II deals directly with the effects of a solar eclipse on a theoretical ionosphere. Ionograms which would be obtained in the theoretical ionosphere are constructed. These are scaled by standard methods to show where errors may arise . It appears that tilts in the layers have only a small effect. The effect of the valley is, however, extremely important, giving rise to the apparent maximum of electron density in the F2 layer at a given height after the eclipse. This maximum does not in fact exist but arises from an error in the scaling method which ignores the possibility of a valley. Some records taken during the solar eclipse of 25 December, 1954 have been scaled. They support the conclusion reached theoretically.
- Full Text:
- Date Issued: 1962
- Authors: Walker, Anthony David Mortimer
- Date: 1962
- Subjects: Solar eclipses , Ionosphere , Solar activity
- Language: English
- Type: Thesis , MSc , Masters
- Identifier: vital:5550 , http://hdl.handle.net/10962/d1013467
- Description: The behaviour of the ionosphere during a solar eclipse is of great interest because radiation from the sun is the cause of ionization in the upper atmosphere and it is useful to be able to conduct experiments where this radiation is cut off and restored in a known manner. Experimental results, especially those dealing with the F2 layer, have proved puzzling. Cusps which cannot be explained appear on the records obtained from ionosphere sounders and in the F2 region the electron density at a given height shows a maximum after the eclipse where one would expect it simply to rise to a steady value. An attempt is made in this thesis to explain some of the anomalies in terms of tilts in the ionospheric layers and minima of electron density or "valleys" between the ionospheric layers. The problem is attacked theoretically. Part I deals with the theoretical background to ionospheric physics in general and to this problem in particular. Standard methods of dealing with radio propagation in the ionosphere as well as some methods developed by the author are discussed. Part II deals directly with the effects of a solar eclipse on a theoretical ionosphere. Ionograms which would be obtained in the theoretical ionosphere are constructed. These are scaled by standard methods to show where errors may arise . It appears that tilts in the layers have only a small effect. The effect of the valley is, however, extremely important, giving rise to the apparent maximum of electron density in the F2 layer at a given height after the eclipse. This maximum does not in fact exist but arises from an error in the scaling method which ignores the possibility of a valley. Some records taken during the solar eclipse of 25 December, 1954 have been scaled. They support the conclusion reached theoretically.
- Full Text:
- Date Issued: 1962
An investigation of the orientation of certain long-chain fatty acids at the air-water interface
- Authors: Saayman, Henry Martin
- Date: 1962
- Subjects: Fatty acids , Surface chemistry
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: vital:4496 , http://hdl.handle.net/10962/d1013117
- Description: The results obtained for the cross-sectional areas of the series of long-chain fatty acids may best be summarized with the aid of Graph 9. This graphical representation of the molecular areas, in Ų , against the chain length (n), of the fatty acid molecules, illustrates variation of the areas with chain length for the series in recrystallized form, and also for selected samples in the zone purified and vacuum distilled forms. On the graph, the limits of variation of the molecular areas have been represented as lines of a length corresponding to twice the standard deviation (2S). This is to give representation that the standard deviation may be positive or negative in relation to the mean. For molecules with n odd and lying between 15 and 19, the molecular area decreases. This may be due to the effect of 3 factorsg (1) A general decrease in lateral translation because of the increasing molecular mass (translational kinetic energy per molecule = ½ mc ⁻²), resulting in closer spacing of molecules. (2) A general, but steady decrease in the angle of tilt of the molecules which thus tend to be held more erect in the condensed film. (3) A general decrease in the precessional motion of the hydrophobic chain groups. For molecules with n odd and between 19 and 23, the molecular areas increase probably due to the steady increase in molecular mass causing the long chains to commence to buckle, tilt or topple in their upper regions. This tilting becomes greater because of the increasing gravitational effect on the heavier molecules which tends to make them assume a flatter posture in relation to the surface. The lower values observed for margaric and nonadecanoic acids, may be due to increasing symmetry in the chain, with corresponding economy in packing in condensed monolayers. This effect may be connected with increasing cylindrical symmetry of the hydrocarbon chain for even values of n. The results of this investigution, incomplete as it is, - serve to indicate what might reasonably be expected to happen in the orientation of these fatty acids in monolayers. Further work, especially on a greater range of acids with even n, is clearly necessary in order to establish the tentative ideas which have been suggested. However, in the present research, work was limited to those acids in the series which were obtainable without undue difficulty or delay, those which would spread readily under the conditions of experiments carried out at 20°C, and those which could be purified relatively easily. The acids below n = 15 in the series were found to be too soluble in aqueous substrates, at operating temperatures of 20°C, to yield reliable evidence with the Langmuir trough technique. The acids above n = 23 were unobtainable commercially and the synthesis of those acids from the lower members in the series presented problems of isolating the required specimens and difficulty in purifying these, which were considered b be beyond the scope of the present research. Summary and conclusion, p. 122.
- Full Text:
- Date Issued: 1962
- Authors: Saayman, Henry Martin
- Date: 1962
- Subjects: Fatty acids , Surface chemistry
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: vital:4496 , http://hdl.handle.net/10962/d1013117
- Description: The results obtained for the cross-sectional areas of the series of long-chain fatty acids may best be summarized with the aid of Graph 9. This graphical representation of the molecular areas, in Ų , against the chain length (n), of the fatty acid molecules, illustrates variation of the areas with chain length for the series in recrystallized form, and also for selected samples in the zone purified and vacuum distilled forms. On the graph, the limits of variation of the molecular areas have been represented as lines of a length corresponding to twice the standard deviation (2S). This is to give representation that the standard deviation may be positive or negative in relation to the mean. For molecules with n odd and lying between 15 and 19, the molecular area decreases. This may be due to the effect of 3 factorsg (1) A general decrease in lateral translation because of the increasing molecular mass (translational kinetic energy per molecule = ½ mc ⁻²), resulting in closer spacing of molecules. (2) A general, but steady decrease in the angle of tilt of the molecules which thus tend to be held more erect in the condensed film. (3) A general decrease in the precessional motion of the hydrophobic chain groups. For molecules with n odd and between 19 and 23, the molecular areas increase probably due to the steady increase in molecular mass causing the long chains to commence to buckle, tilt or topple in their upper regions. This tilting becomes greater because of the increasing gravitational effect on the heavier molecules which tends to make them assume a flatter posture in relation to the surface. The lower values observed for margaric and nonadecanoic acids, may be due to increasing symmetry in the chain, with corresponding economy in packing in condensed monolayers. This effect may be connected with increasing cylindrical symmetry of the hydrocarbon chain for even values of n. The results of this investigution, incomplete as it is, - serve to indicate what might reasonably be expected to happen in the orientation of these fatty acids in monolayers. Further work, especially on a greater range of acids with even n, is clearly necessary in order to establish the tentative ideas which have been suggested. However, in the present research, work was limited to those acids in the series which were obtainable without undue difficulty or delay, those which would spread readily under the conditions of experiments carried out at 20°C, and those which could be purified relatively easily. The acids below n = 15 in the series were found to be too soluble in aqueous substrates, at operating temperatures of 20°C, to yield reliable evidence with the Langmuir trough technique. The acids above n = 23 were unobtainable commercially and the synthesis of those acids from the lower members in the series presented problems of isolating the required specimens and difficulty in purifying these, which were considered b be beyond the scope of the present research. Summary and conclusion, p. 122.
- Full Text:
- Date Issued: 1962