The pulse technique was employed to measure velocities of longitudinal and transverse mechanical waves in solid iodine at ultrasonic frequencies. Pulses were produced and their echoes displayed by a Sperry Ultrasonic Attenuator Comparator. Transducers for generating the waves were: longitudinal waves, X-cut quartz crystals of 5 and 12 Mcs.; transverse waves, Y-cut quartz crystal of. 5 Mcs. For longitudinal measurements the sample was immersed in baths of liquid helium, liquid nitrogen, solid carbon dioxide, ice, ambient room temperature, and boiling water. No dispersion was found. Four samples were used, but as iodine is anisotropic in many of its physical properties most attention was paid to two amorphous samples which were thought to give representative average values of the properties of iodine. From the values of longitudinal velocity, Young's modulus was calculated. Transverse velocity measurements were made in baths of liquid helium, liquid nitrogen, carbon dioxide, and ambient room temperature. The shear, modulus was determined from the transverse velocity; compressibility was found from Young's modulus and the shear modulus. All these quantities behave much as would be expected of a solid material. The Debye characteristic temperature calculated from the longitudinal and transverse velocities was compared with values calculated from specific heat data and Lindemann melting point formula. / Science, Faculty of / Physics and Astronomy, Department of / Graduate

Stridulation in the waterbug genus Cenocorixa was studied in the field and experimentally in the laboratory. It was shown that both males and females stridulate. The stridulatory signals, analysed by use of a sound spectrograph, were shown to be species and sex specific, differing in temporal pattern of pulses, pulse rate, pulse structure, and signal length. It was shown that the annual rhythm of stridulation in both male and female is correlated with sexual maturity. Males will spontaneously stridulate when there is mature sperm in the testes, and this occurs in spring, early summer, and late fall. Females do not stridulate spontaneously, but can be induced to stridulate when they have chorionated eggs in the lateral oviducts, but no sperm in the receptaculum seminis; they are sexually mature only in the spring and early summer. Stridulation was shown to be important in behavior leading to successful copulation. Male stridulation functions as a calling signal facilitating pair-formation by attracting conspecific females, and as an agonistic signal serving to space out individuals. Males will answer almost any stridulatory signal, but only calls from a conspecific female initiate searching behavior. Receptive females respond to stridulatory stimuli from conspecific males by stridulating, and successful copulations were observed only when preceded by such signal recognition; female stridulation functions as an agreement signal. Stridulation serves as a premating isolating mechanism in Cenocorixa. However, it is not the only isolating mechanism, but is reinforced by geographic and ecological isolation in a number of cases. The Corixidae, since they mostly have only a single stridulatory signal that can function in at least two contexts, are considered to represent a primitive stage in evolution of stridulatory signals: a stage in which functional diversification of signals is just evolving. / Science, Faculty of / Zoology, Department of / Graduate

The Central Statistical Services (CSS) currently estimates that there are approximately 412 421 profoundly deaf people and approximately 1 237 264 extremely heard-of-hearing people in South Africa. Irene Bester of the SABC has noted that there may even be around 2 million people in South Africa who regard sign language as their fi rst language. It is estimated that the number of deaf and hard of hearing people stands at 5 million (Kruger 2000:35). According to Ethnologue there are 12 100 deaf persons in South Africa, including 6 000 Black, 2 000 English white, 2 000 Afrikaans white, 1 200 Coloured and 900 Indian (Gallaudet University 1986). Whilst there are a number of primary and secondary institutions dedicated to the education of the deaf and hard of hearing, facilities which function on a tertiary level are limited. Research has indicated that there exists a dire need for a facility to fi ll this void, and to simultaneously accommodate experiential spaces as well as the administrative functions required for the proper management of the needs of this sector of the population. The main objective of this dissertation is to create a centralized facility for the deaf and hard of hearing in Tshwane. This facility would focus on the wellbeing of the student and facilitate his or her introduction into society as a productive and well adapted individual through specialized and career orientated training and experiential exposure. As discussed in this document, the facility will serve as the headquarters for DEAFSA in Pretoria and also as a training facility in various fi elds. The provision of adequate and well-appointed facilities for the development of life skills for the deaf and hard of hearing is of paramount importance to achieve this objective. Apart from the educational and administrative components, one of the main features of the facility will be a Sound Exploratorium. This will be a space where sound will be introduced through the four other senses, making it possible for those who are hearing impaired to experience sound. Curiosity is intensifi ed when the use of one sense is limited or totally absent. Sound will become another dimension of the architecture and will be introduced through the building fabric and other media. The individual will be guided through the building and experience the sounds of the city and their environment through their other senses. Tagged sensory movement will guide the user through the facility, giving the individual a sense of power and accomplishment, and thus increasing the intensity of the experience. The architecture becomes a stage for activities where the visual and experiential dominates spatial understanding. The facility will enable the user to experience the city in a different way and become aware of how sound influences us within the built environment. / Dissertation (MArch(Prof))--University of Pretoria, 2008. / Architecture / unrestricted

Syftet med det här arbetet har varit att utveckla ett eget sound inom a capella/stämsång genom att studera fem vokalgrupper, komponera två egna låtar och arrangera om två befintliga låtar. I arbetet försökte jag ta reda på vad det verkligen innebar att skriva a capella och vilka musikaliska val jag kunde göra som låtskrivare/arrangör för att få till det soundet jag ville åt. Under arbetets gång har jag fördjupat mina kunskaper i att arrangera körstämmor till en vokalgrupp. Jag lärde mig också vilka olika sound jag tycker om och vad jag vill undvika i mitt skrivande/ arrangerande, de val jag måste göra för att nå mitt önskade sound. Jag har länge haft en dröm om att ha en egen vokalgrupp där jag skriver de olika arrangemangen och jag har efter det här arbetet blivit mer bekväm i rollen som körledare/producent. Arbetets konstnärliga del har jag presenterat med klingande exempel från min konsert.

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