Volume 4

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    The importance of nuclear magnetic resonance in elucidating the chemical structures of active components found in medicinal plants indigenous to Namibia
    (University of Namibia, 2014) Knott, Michael G.; Lates, Jennie; Ishola, Anthony
    Namibia has a vast plant biodiversity which, supported by strong Indigenous Knowledge Systems, could lead to the development of active drugs from one or more of the indigenous plants. This notification paper examines how Namibia is hampered from taking control of and developing its own natural product resources due to a lack of Nuclear Magnetic Resonance (NMR) technology.
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    Technological theory of nanometer-ZnO production in industry
    (University of Namibia, 2014) Wang, Jiu Liang
    In terms of chemical engineering theory, the operating domain of nanometer ZnO production has been analyzed in detail by means of uniform precipitated method. The reacting system of ZnO production is a complicated system with series, parallel, reversible, and multiphase reactions. The author finds that the independent reaction number is 6. The free degree of the reactions is 7. The proportional ratio of reactants is C(CO(NH2)2):C(Zn(NO3)2) 3.5 : 1. The operating domain is illustrated by the proportional concentrations CO(NH2)2: Zn2+ = 1 : 2.5; Zn2+:H2O=1:11; CO(NH2)2:H2O=1:3. The value of pH is key factor of the reaction system and a better pH value is 6.5. Other key factors are temperature and time of the reactions.
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    An inexpensive new multipurpose refrectometer
    (University of Namibia, 2014) Shafudah, Natangue H.; Singh, Shyam
    A new yet very inexpensive refrectometer for the determination of refractive index and impurity in liquids at instant has been proposed. This refrectometer requires a high resolution grating, a low power laser and a position detector. The position detector analyses and determines the impurity in a liquid directly based on its refractive index. The use of a plane mirror enhances the accuracy of the refractive indices as the measurements of required parameters are greatly increased.
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    Corrosion of selected hard facing materials exposed to mine water
    (University of Namibia, 2014) Hango, Silas I.; Chown, L.H.; Van der Merwe, J.W.; Kavishe, Frank P.; Cornish, L.A.
    Corrosion damage can cause major failure of mining pumps which could lead to degradation of other mining equipment, as a result of leakage, thus leading to a high rate of replacement and maintenance of pumps and surrounding equipment. Hard facing materials are used to protect moving parts against mechanical and corrosion damage. The corrosion behavior of a corrosion resistant Hastelloy G30 and a hard facing material, a nickel-chromium-iron (Ni-Cr-Fe) alloy (both high chromium nickel-based alloys) exposed to synthetic and acidified mine water were studied using potentiodynamic polarisation. The results showed lower corrosion rates for Hastelloy G30 than for Ni-Cr-Fe. The corrosion rates at pH 6.8, at ambient temperature and 35 C were 0.00011 mm.y−1 and 0.00035 mm.y−1 for Hastelloy G30; 0.0016 mm.y−1 and 0.0017 mm.y−1 for INCONEL Alloy 600, and at pH 3, at ambient temperature and 35 C corrosion rates were 0.0003 mm.y−1 and 0.00083 mm.y−1 for Hastelloy G30; 0.1 mm.y−1 and 3.2 mm.y−1 for INCONEL Alloy 600. The microstructures of the alloys before and after corrosion tests were characterised using optical microscopy; X-ray diffraction (XRD), and microhardness measurements were also performed.
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    The Feeding habits of the Giant African Bullfrog (Anura: Pyxicephalidae: Pyxicephalus Adspersus Tschudi, 1839) of the Cuvelai Drainage System in Northern Namibia
    (University of Namibia, 2014) Okeyo, Daniel O.; Kashea, Martha M.; Kandjengo, Lineekela
    The recorded diet of the giant African bullfrog Pyxicephalus adspersus of the Cuvelai drainage plains (the oshanas) of northern Namibia is presented. Among all the stomach contents; insects accounted for the greatest diversity of the orders recorded. The most abundant prey items to the juvenile frogs come from Orthoptera (20.0%), Lepidoptera (16.0%), Isoptera (15.5%), Coleoptera (12.0%), while to the adult frogs also come from Orthoptera (20.0%) but followed by Coleoptera (11.8%), Odontata (11.0%) and Hemiptera (10.0%) in that hierarchical order. A habit of cannibalism is indicated; tadpoles form the fifth (11.0%) and second (13.1%) most important food item for juvenile and adult frogs, respectively. Diet shift is evident, from ants to tadpoles and beetles as the frogs become larger.
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    An empirical analysis of the risk factors that lead to Juvenile Delinquency among high school
    (University of Namibia, 2014) Sinyangwe, Yande; Muller, Maria A.
    Juvenile Delinquency has become a major issue in Namibia and globally, receiving a considerable amount of attention from the media and politicians, as it is widely believed by criminologists and sociologists alike, that most adult criminals started out as juvenile delinquents. The increasing levels of juvenile delinquency in Namibia, Windhoek in particular have become a matter of national concern. Much of the effort, thus far, has been focused on punishment and correctional measures but little has been done on prevention and intervention. This study attempts to provide an empirical understanding of the risk factors that lead to Juvenile Delinquency in Windhoek. To fully answer the research questions, a mixed method approach comprising qualitative and quantitative methods was carried out. Results show that a significant difference in attitude towards school exists between learners from low and high density areas. A further examination of these results, show that learners tend to uphold delinquency as acceptable. We also note that learners from higher density areas appear to have a negative attitude towards life. Based on these results, we conclude that Juvenile Delinquency among high school learners in Windhoek is a cultural demeanor as the results are similar regardless of respondents’ residential density and location of school. The results of this study will be significant in that they will help policy makers and members of society understand the underlying factors that are likely to lead youths into delinquent behaviour. This in turn will help stakeholders come up with more effective preventive and intervention programs.
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    Characterization of A8 by 3-Centralizers
    (University of Namibia, 2014) Ligonnah, A.
    Let G be a finite group containing a subgroup H isomorphic to an alternating group, An, such that G satisfies the 3-cycle property, namely ’for a 3-cycle x 2H, if xg 2H for any g 2 G, then g 2 H.’It is proved that for n = 8, G is isomorphic to LK, an extension of an elementary Abelian 2-group L by a group K isomorphic to either A8 or SL(5, 2). If G is simple, it is shown that G is isomorphic to A8 or SL(5, 2).
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    Identification and selection of superior phenotypes of Uapaca Kirkiana Muell Arg. (Euphorbiaceae), a priority indigenous fruit tree of Zimbambwe
    (University of Namibia, 2014) Dhliwayo-Chiunzi, P.D.; Matimati, I.; Kachigunda, B.
    The International Centre for Research in Agroforestry (ICRAF now known as the World Agroforestry Centre) initiated research and development work on at least 20 priority indigenous fruit trees in 5 countries in Southern Africa including Zimbabwe. The long term objective of this work was to improve food security and income generating capacities of local communities through domestication, marketing and commercialisation of indigenous fruit trees. Country specific priority species were identified based on consultations with a wide range of users. For Zimbabwe, Uapaca kirkiana emerged as a priority species with economic potential and has since become the focus of intensive research. A study aimed at identifying and selecting superior phenotypes of U. kirkiana was initiated in six districts of Murehwa (Natural Region I), Goromonzi (Natural Region II), Rusape (Natural Region II), Bindura (Natural Region II), Masvingo (Natural Region III) and Gokwe (Natural Region IV). Participatory Rural Appraisal (PRA) techniques in the form of group discussions amongst researchers, extensionists, school children, vendors and processors led to the identification of 48 trees of superior phenotypes. Tree location and altitude were recorded using the Geographical Positioning System (GPS). Fruit size, colour, shape were recorded. Total Soluble Solutes (TSS %) was measured using a hand refractometer. The largest fruits (42.3 g/fruit) were collected from Gokwe (ICR03GokZW41) whilst the smallest fruits (9.1 g/fruit) were collected from Rusape (ICR03RusZW53). Fresh fruit weight was strongly correlated to the seed weight (r = 0.813). Fruits with higher pulp content had a lower seed weight (r = −0.452). Fruits from Gokwe and Masvingo had higher TSS percentage. Basing on stakeholders’ selection criteria and laboratory analysis, 23 trees above the mean fruit weight (20.63 g/fruit) were classified as large, whilst 24 trees with pulp content above the mean of 45.18% were classed as pulpy and 22 trees with TSS above 19.53% were classed as sweet. Similarity of the phenotypes was determined through complete linkage in hierarchical cluster analysis. Clustering confirmed the characterisation by farmers using taste as a key method of selecting suitable phenotypes. In-situ conservation and establishment of clones from the selected trees is recommended for purposes of commercialising these superior phenotypes.
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    Assessment on the effect of Lignin as a feed additive for lohmann brown egg layer chickens: A case study at Neudamm farm, University of Namibia
    (University of Namibia, 2014) Mausse, Francisco; Lyaku, Japhet R.; Beukes, Edmond; Nafenya, Lazarus
    Namibian environmental conditions. A total of 871 chickens (482 experimental and 489 control groups), weighing an average mass of 2 kg/head, were subjected to an experiment under Neudamm Campus (UNAM) environmental conditions (32 C average temperature and 22% relative humidity). All chickens were fed with ordinary balanced ration earmarked for egg layers for 8 days and subjected to stress for 10 minutes per day. The experimental group was given purified lignin (Lignohumate KD) 60 mg/kg diluted in a litter of drinking water, as an anti-stressor feed additive and metabolic activity stimulator. Results of this study revealed an increase in egg production, reduction in feed intake, resistance to stress, and production of eggs of bigger sizes (graded as Extra-large), with strong shells as compared to those produced by the control group. At a certain stage, some chickens from the experimental group were unable to release eggs freely, a fact possibly related to egg size and possible deficient lubrication of cloacal environment. Studies are ongoing with the objective of identifying accurate amounts of lignin/kg necessary to feed egg-layer chickens for triggering an improvement of egg quality under Namibian environmental conditions, without affecting the bird’s physiology and health.