Browsing by Title
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Taiwo, A.A. (Taylor & Francis, http://www.tandf.co.uk/journals, NaN, 1999)[more][less]
Abstract: The study was designed to elucidate the nature of the perception of the water cycle held by Botswana pupils in standards 4 to 7 of primary schools in three different areas (namely, remote area dwellers’ settlement, peri-urban and urban areas) of Botswana. The research design employed a survey method involving the administration of a structured instrument and interview sessions for data collection. Analyses of research data were carried out by both qualitative and quantitative methods. Among other things, the outcome of the study showed that the perception of water cycle held by the study sample was positively influenced by schooling but negatively impacted upon, to some extent, by the ’untutored’ ideas the children brought to school. URI: http://hdl.handle.net/10311/1111 Files in this item: 1
Taiwo_IJSE_1999.pdf (1.131Mb) -
Uziak, J.; Loukanov, I. A. (CIGR Journal http://www.cigrjournal.org/, NaN, 2007)[more][less]
Abstract: The ram-press technology for oil expression has received a lot of attention in many African countries during the last two decades. The technology is based on manually operated mechanical presses, which employ a slider-crank mechanism in two different configurations. The original machine was invented by Karl Bielenberg in 1985 and since then continuous design improvements have been made to improve their performance and ease of operation. This paper deals with the performance of some commonly used ram press machines such as BP-35, BP-30 and FI-32, in order to establish their suitability for small rural oil expression technology. The available oil-seed processing techniques were discussed, including their suitability for locally grown sunflower varieties, and the characteristics of the ram press machines. The machines were tested by using three varieties of sunflower seeds, namely PNR 7225, PNR 7369, and Peredovik. The machines were compared by their outputs obtained when conducting a high production and high expression tests. Based on the above analysis the Camartec design (BP-30) was found to have the best performance. The machine had the highest efficiency and also the highest expression rate in comparison to CAPU design (BP-35) and RAM design (FI-32) machines. The FI-32 machine was found to be ineffective, having in the high expression test an expression rate below 20% irrespective of the type of seeds used. In terms of the speed of oil production the CAPU (BP-35) design performed better then the other machines. However in the high production test its performance was similar to that of Camartec machine. URI: http://hdl.handle.net/10311/697 Files in this item: 1
Uziak_AEI2_2007.pdf (989.2Kb) -
Pansiri, N.O. (EMAL, http://ema.sagepub.com, November NaN, 2011)[more][less]
Abstract: The thesis of this article is that the uncritical adoption of Western models of education management and leadership policies results in poor performance in schools in disadvantaged communities in developing countries. The argument shows that this has led to the institutionalizationof generic education policies that are not contingent to the circumstances of the small, dispersed, rural and remote schools. In my analysis, I agree with the growing concern in educational development debates over the uncritical transportation or the uncritical international transfer of school effectiveness assumptions and models to African contexts. I use Botswana as a case study to show the continuing mismatch between educational management models adopted from Western countries and the application in the Botswana context, and the related failure of school improvement initiatives proposed by aid agencies. When a school fails the head is charged with the underperformance. URI: http://hdl.handle.net/10311/1116 Files in this item: 1
Pansiri_EMAL_2011.pdf (3.133Mb) -
Ntseane, D.M. (Pula: Botswana Journal of African Studies, NaN, 2004)[more][less]
Abstract: This article analyses the findings of a study conducted to investigate the effects of teacher transfers onfamily well-being. While much concern has been raised about the trauma of transfers on families, this is the first empirical study conducted to investigate these concerns. The primary aim of the study was therefore to understand the experiences of teachers affected by transfers. Data was collected using a survey questionnaire addressed to 361 transferred teachers in selected primary and secondary schools. In addition face-to-face indepth interviews were conducted with 20 couples. The findings suggest that transfers are a source of great strain when separate residences have to be maintained as a result of the transfer. In general couples experience enormous challenges in their marriages. They have difficulties parenting at a distance and are financially burdened due to maintaining two separate homes. The study provides much-needed literature on the impact of personnel transfers on families. It also offers policy makers and practitioners with a sound information base for the development of transfer policy that takes family needs into consideration. URI: http://hdl.handle.net/10311/899 Files in this item: 1
Ntseane2_PBJAS_2004.pdf (711.3Kb) -
Batumike, M.J.; Kampunzu, A.B.; Cailteux, J.H. (Elsevier www.elsevier.com/locate/jafrearsci, NaN, 2006)[more][less]
Abstract: The Nguba and Kundelungu Groups constitute the middle and upper parts of the Neoproterozoic Katangan Supergroup, respectively, and consist of conglomerates, sandstones, mudrocks and carbonates. During deposition, the Katangan basin received sediments originating from both northern and southern sources. The Nguba and Kundelungu Groups siliciclastic rocks have elemental abundances and ratios suggestive of a relatively felsic TTG source, although slightly more mafic compositions occur in the Nguba Group and the overlying ‘‘Petit Conglome´rat’’ Formation at the base of the Kundelungu Group. Modal compositions of the Nguba Group rocks indicate a basement uplift provenance, and geochemical parameters indicate the source of both the Nguba and Kundelungu Groups had an active continental margin character. Source area weathering was moderate in the Nguba Group. Low Chemical Index of Alteration (CIA) and Plagioclase Index of Alteration (PIA) indices and relatively uniform chemical compositions of the ‘‘Grand Conglome´rat’’ and the ‘‘Petit Conglome´rat’’ Formations lying respectively at the bases of the Nguba and Kundelungu Groups are compatible with deposition in a cool or frigid climate, and support their presumed petrographic based glaciogenic origin. High CIA and PIA indices in Upper Kalule rocks in the middle part of the Kundelungu Group point to the intensification of source weathering, possibly under tropical to subtropical climate under steady state conditions. Geochemical similarities between the Nguba Group and the ‘‘Petit Conglome´rat’’ are compatible with a change from an extensional setting to compression, with derivation of the ‘‘Petit Conglome´rat’’ by reworking of the underlying units during basin inversion. Change in provenance signatures and weathering indices in the Upper Kalule Formation may reflect reduced tectonism and resumption of supply of more weathered extrabasinal detritus, similar to that which fed the basal Roan Group. Overall the data suggest derivation mainly from pre-Katangan Proterozoic sources with continental arc characteristics. The adjacent Paleoproterozoic Ubendian Belt, particularly the Bangweulu block calcalkaline plutonic and volcanic province, is a suitable candidate as the source for the Nguba and Kundelungu Group sedimentary rocks. However, Mesoproterozoic and Archaean terrains have also contributed a minor component to the basin. URI: http://hdl.handle.net/10311/392 Files in this item: 1
Kampunzu2006Petrologyandgeochemistry.pdf (1.585Mb) -
Kumar, J.; Ahmad, M.; Chander, R.; Thangaraj, R.; Sathiaraj, T.S. (EDP Sciences, NaN, 2008)[more][less]
Abstract: Effect of Pb substitution on the amorphous-crystalline transformation temperature, optical band gap and crystalline structure of Ge2Sb2Te5 has been studied. In Pb:GeSbTe chalcogenide films prepared by thermal evaporation, an amorphous to crystallization transition is observed at 124, 129, 136 and 138 ◦C in Pb0Ge20Sb24Te56, Pb1.6Ge19Sb26Te54, Pb3Ge17Sb28Te53 and Pb5Ge12Sb28Te55 respectively. XRD investigations of annealed samples reveal that Pb substitution retains NaCl type crystalline structure of GST but expands the lattice due to large atomic radii. The increase in amorphous-crystalline transformation temperature is followed with the increase in phase segregation. The optical gap shows marginal variations with composition. URI: http://hdl.handle.net/10311/531 Files in this item: 1
Phase segregation.pdf (573.5Kb) -
Kumar, J.; Ahmad, M.; Chander, R.; Thangaraj, R.; Sathiaraj, T.S. (EDP Sciences. http://www.epjap.org/, NaN, 2008)[more][less]
Abstract: Effect of Pb substitution on the amorphous-crystalline transformation temperature, optical band gap and crystalline structure of Ge2Sb2Te5 has been studied. In Pb:GeSbTe chalcogenide films prepared by thermal evaporation, an amorphous to crystallization transition is observed at 124, 129, 136 and 138 ◦C in Pb0Ge20Sb24Te56, Pb1.6Ge19Sb26Te54, Pb3Ge17Sb28Te53 and Pb5Ge12Sb28Te55 respectively. XRD investigations of annealed samples reveal that Pb substitution retains NaCl type crystalline structure of GST but expands the lattice due to large atomic radii. The increase in amorphous-crystalline transformation temperature is followed with the increase in phase segregation. The optical gap shows marginal variations with composition. URI: http://hdl.handle.net/10311/278 Files in this item: 1
Kumar_EPJAP41_2008.pdf (796.1Kb) -
Goodwin, J.W.; Hughes, R.W.; Kwaambwa, H.M.; Reynolds, P.A. (Elseview Science B.V. www.elsevier.nl/locate/colsurfa, NaN, 2000)[more][less]
Abstract: A series of well characterised cis-polyisoprene polymers have been added to dispersions of PHS coated PMMA particles in dodecane. At a molecular weight of 8000 g mol−1 and above, these systems showed phase separation at low particle volume fractions and above a critical polymer concentration. The rate of separation has been shown to be influenced by the viscosity of the polymer. At high polymer and particle volume fractions long lived metastable phases occurred. Above a critical concentration these were viscoelastic indicating an appreciable change in diffusion dynamics with two relaxation processes present. A significant Bingham yield stress was also observed. The Asakura Oosawa potential was not able to describe the observed rheological properties. At a molecular weight of 1000 g mol−1 no phase separation was observed. At high particle concentrations the yield stress was found to reduce with the addition of polymer. This was due to the polymer acting as a ‘solvent’ and penetrating the stabilising layer on the particles. URI: http://hdl.handle.net/10311/329 Files in this item: 1
Phase separation behaviour.pdf (2.723Mb) -
Kezilahabi, E. (Taylor and Francis, NaN, 2001)[more][less]
Abstract: This article argues that greeting among the Kerebe is a phenomenological project of everydayness in which the concept of being manifests itself in a dialogic manner. This is revealed through the four variables on which greetings are based: time, age, gender and relationship. The variables give us a glimpse of how the Kerebe view the question of temporality of being, the idea of being-for-the-other and the question of truth; and they cast some light on the general concept of a person in Kerebe thought. The article is oriented toward an inquiry into the concept of being-in-the-world from an African point of view. URI: http://hdl.handle.net/10311/421 Files in this item: 1
Kezilahabi_JACS_2001.pdf (1.480Mb) -
Munkombwe N.M. (Elsevier Ltd. www.elsevier.com/locate/phytochem, NaN, 2003)[more][less]
Abstract: Two phenylpropanoid glucosides, 2-O-b-d-glucosyloxy-4-methoxybenzenepropanoic acid and its methyl ester, together with syringin and adicardin were isolated from the stem of Gnidia polycephala and characterized by physical and spectroscopic data. URI: http://hdl.handle.net/10311/275 Files in this item: 2
Phenylpropanoid glycosides.pdf (2.288Mb)Phenylpropanoid glycosides of Gnidia.pdf (155.6Kb) -
Nijegorodov, N.; Zvolinski, V.; Luhanga, P.V.C.; Mabbs, R.; Ahmad, J. (Elsevier Ltd. www.elsevier.com/locate/saa, NaN, 2006)[more][less]
Abstract: The multi-banded fluorescence and laser properties of 11 new amino- and tosylamino derivatives of 2,5-di(phenyl)-1,3,4-oxadiazole and oxadiazole in various solvents at 293 K are reported. All the compounds investigated possess intra-molecular hydrogen quasi-bond (IHB) of 4.6-5.2 kcal mol-1 in the ground state. In the excited state they can undergo protolytic dissociation or intra-molecular photon-initiated transfer of proton and reveal anomalous fluorescence which cannot be explained within the framework of the Kasha and Kasha-Vavilov rules. Depending upon the excitation wavelength, solvent, concentration and pH of the medium, the compounds studied show a single, double, triple or even a four-banded fluorescence, which has not been reported earlier. The nature of multi-banded fluorescence is explained in terms of the possible photochromic processes in excited states. Quantum yields and decay times of the different fluorescence bands are reported. Anomalous dependence of quantum yield upon concentration of the solution is observed. Laser properties of the compounds studied are carefully tested. Laser action based on the fluorescence of the so-called bi-radical molecules is reported. Various possible arrangements of singlet and triplet levels of compounds investigated are discussed. URI: http://hdl.handle.net/10311/176 Files in this item: 2
license.txt (1.998Kb) -
Nijegorodov, N; Zvolinski, V; Luhanga, P V C; Mabbs, R; Ahmad, J (Elsevier Science Ltd. www.elsevier.com/locate/saa, NaN, 2006)[more][less]
Abstract: The multi-banded fluorescence and laser properties of 11 new amino- and tosylamino derivatives of 2,5-di(phenyl)-1,3,4-oxadiazole and oxadiazole in various solvents at 293K are reported. All the compounds investigated possess intra-molecular hydrogen quasi-bond (IHB) of 4.6–5.2 kcal mol−1 in the ground state. In the excited state they can undergo protolytic dissociation or intra-molecular photon-initiated transfer of proton and reveal anomalous fluorescence which cannot be explained within the framework of the Kasha and Kasha–Vavilov rules. Depending upon the excitation wavelength, solvent, concentration and pH of the medium, the compounds studied show a single, double, triple or even a four-banded fluorescence, which has not been reported earlier. The nature of multi-banded fluorescence is explained in terms of the possible photochromic processes in excited states. Quantum yields and decay times of the different fluorescence bands are reported. Anomalous dependence of quantum yield upon concentration of the solution is observed. Laser properties of the compounds studied are carefully tested. Laser action based on the fluorescence of the so-called bi-radical molecules is reported. Various possible arrangements of singlet and triplet levels of compounds investigated are discussed. URI: http://hdl.handle.net/10311/247 Files in this item: 2
license.txt (1.998Kb)Nijegorodov_SAa65_2006.pdf (2.225Mb) -
Murty, V.R.K.; Devan, K.R.S. (Elsevier Science Ltd. www.elsevier.com/locate/radphyschem, NaN, 2004)[more][less]
Abstract: The interaction of photons with matter has been extensively studied over the past several decades in view of its importance in basic radiation physics research, medical, industrial and other applied fields. Large amounts of data have been complied on photon cross sections mostly in tabular and graphical forms (Hubbell, 1999, 1994; Berger and Hubbell, 1987). A careful survey of the latest bibliography (Hubbell, 1994) of experimental investigations shows gaps in the cross section data, especially in certain low-Z elements. These are mainly attributed to the difficulty in procuring thin absorbers in suitable form for low energy experiments. It was also evident from the bibliography that the cross section data was sparse for elements Mg and V, especially, using high resolution solid state detectors in the photon energy region below 100 keV. URI: http://hdl.handle.net/10311/266 Files in this item: 1
Murty_RPC_2004.pdf (191.6Kb) -
Nijegorodov, N.; Zvolinsky, V.; Luhanga, P.V.C. (Elsevier Science Ltd. www.elsevier.com/locate/jphotochem, NaN, 2008)[more][less]
Abstract: Intramolecular processes and fluorescence properties of 32 specially chosen aromatic molecules, different in degrees of planarity and rigidity, but family related in -structure are experimentally and theoretically (using the PPP-method) studied at room temperature (293 K). The quantum yields of fluorescence , and decay times τf, of deaerated and non-deaerated cyclohexane solutions are measured. The oscillator strength fe, the fluorescence rate constants kf, the natural lifetimes τT o , and the intersystem crossing rate constants kST, are calculated. The investigations showed the following differences in the behaviour of the fluorescence parameters in transition from the non-planar molecule to the planar and more rigid-type: the value of the symmetry line wave-number υ00 (the frequency of the S0→S1 * transition) and the Stokes shift υST, decrease. The oscillator strength and fluorescence constant, normally decrease. The change in the quantum yield of the fluorescence depends upon the changes in the kf and kST values. Furthermore, the intersystem crossing rate constant generally decreases, sometimes very significantly. However, there are some interesting exceptions. For example, the kST value of the non-planar molecule of 9,10-diphenylanthracene is less than the kST value of the planar and very rigid molecule of anthracene. This important phenomenon is explained. The differences of the intramolecular processes of planar and non-planar molecules are discussed. The photochemical stability of planar and non-planar molecules is studied. The effect of planarity, rigidity and molecular symmetry upon laser properties is also traced. URI: http://hdl.handle.net/10311/367 Files in this item: 1
Nijegorodov_JPPaC196_2008.pdf (1.901Mb) -
Physically active lifestyle and the development and sustenance of healthy human and economic sourcesOnyewadume, I.U. (Boleswa, http://bera.co.bw, NaN, 2002)[more][less]
Abstract: Dedicated participation in leisure/recreational and competitive physical activities have been known to develop the physical fitness and the physical working capacity (PWC) of the individuals concerned. In the same vein, improved physical fitness and PWC lead to improved productivity in any group of people in their various professions. The ultimate goal of any profession is the provision of abundant economic and material benefits through the development of fit and capable human resouces. Thus, this paper aims at bringing to the fore the modalities through which a countyr's human resource can be galvanized into a fit and physically empowered factor of production for the achievement of material and economic prosperity. URI: http://hdl.handle.net/10311/721 Files in this item: 1
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Mphale, K.M.; Heron, M.L. (Elsevier Science Ltd. www.elsevier.com/locate/jastp, NaN, 2007)[more][less]
Abstract: The flames of wildfires are weakly ionized gas. The ionization is mainly due to omnipresent alkali and alkaline earth metal species that are emitted from thermally decomposing plant structure into the flame during a wildfire. The amount of ionization in flames with alkali impurities is a factor of both the temperature and the quantity of the emitted alkali species in vegetation. Assuming a Maxwellian velocity distribution of flame particles and collision frequencies much higher than plasma frequencies, the propagation of radio waves through wildfires is predicted to have attenuation and phase shift. A theoretical model has been developed to predict propagation characteristics of HF–VHF radio signals at normal incidence to a high intensity wildfire fuel–flame interface. At the interface, the flame medium is modelled by a series of mini-slabs, each with a different but fixed electron density and dielectric permittivity governed by the Rayleigh distribution of temperature. Electron density in each mini-slab is calculated from thermal ionization of alkali species assuming the existence of thermal equilibrium. The model predicts average electron densities ranging from 10¹4 to 10¹7m–³ for fuel–flame interfaces with maximum temperatures from 900 to 1200 K. Specific attenuation and phase shift for propagation in the ionized gas are calculated from the predicted average electron density and collision frequency. At collision frequency of 10¹¹ s–¹, radio signal specific attenuation for the simulated grassfires range from 0.001 to 0.49 dBm–¹ while specific phase shift ranged from 0.0002 to 152°m–¹ for the maximum temperature range of 900–1150 K. URI: http://hdl.handle.net/10311/269 Files in this item: 1
Mphale_JASTP69_2007.pdf (2.265Mb) -
Garg, A.K.; Van Tonder, R.; Joubert, R.J.O. (Inderscience Enterprises Ltd. http://www.inderscience.com/browse/index.php?journalID=235, NaN, 2007)[more][less]
Abstract: In order to analyse the strategic issues with regard to the South African Platinum Group of Metals (PGM) industry, a risk analysis and an assessment of the competitiveness of the industry were conducted. The analysis of risk related to market conditions indicates a relatively low risk rating driven by increased demand for jewellery and autocatalysts, while the industry is exposed to moderate risk for raw materials and supporting services, which is expected to remain moderate in future. Overall, the current risk for production factors was found to be moderate and is expected to remain moderate over the medium term. The results of industry risk analysis indicate that the PGM industry is currently exposed to moderate risk. Applying Porter’s diamond model (Porter, 1990), the research found that the South Africa’s PGM industry has a very strong platform and is expected to become more competitive in future, although increased cooperation will still be evident. The competitiveness of South African producers is expected to increase over the medium term, since most of the expansion will come on stream in the near future. The paper also discusses the development potential of South Africa in line with the exploitation of PGM. URI: http://hdl.handle.net/10311/295 Files in this item: 1
Garg_IGICBM_2007.pdf (2.472Mb) -
Marobela, M.N.; Mawere, S.P. (Academic Journals, http://www.academicjournals.org, July 4, 2011)[more][less]
Abstract: This paper explores the implementation of public sector performance reforms in Botswana magistrate courts to improve service delivery. The authors argue that it is imperative for management to consider the possibility of the unintended outcomes in public sector reforms something that is normally ignored when introducing change. Critical realist philosophy has been adopted as a guiding paradigm for this study. The main contention is that the social world exists independently of the researcher. In this study realist philosophy was used together with the case study methodology to give context. In the courts performance management was supposed to help improve service delivery by reducing court congestion, legal costs, and delays. However, the findings suggest that this has not been the case because of gaming and manipulation of performance measures. A principal constraint in writing this paper was the absence of relevant literature in Botswana. Data was sourced from one organisation used as a case study. Problems like the backlogs of cases and delays affect both the fairness and efficiency of the judicial system. Efficiency has to take account of other factors. Developing performance management systems that incorporate measurement and evaluation in the public sector continues to be a key challenge. Both the positive and negative effects of PMS must be embraced. URI: http://hdl.handle.net/10311/1083 Files in this item: 1
Marobela and Mawere_AJBM_2011.pdf (1.154Mb) -
Kwadiba, M.T.O.G.; Wright, C.; Kgaswane, E.M.; Simon, R.E.; Nguuri, T.K. (Elsevier Science Ltd. www.elsevier.com/locate/lithos, NaN, 2003)[more][less]
Abstract: Pn arrivals from mining-induced earthquakes on the edge of the Witwatersrand basin show that the P wavespeeds in the uppermost mantle are almost constant throughout most of the Kaapvaal craton. The presence of only small wavespeed variations allows the use of a simple method of estimating crustal thicknesses below the stations of the Kaapvaal broad-band network using Pn times that has been compared with results from receiver functions. One thousand three hundred thirty-seven Pn arrivals were used to derive crustal thicknesses at 46 stations on the Kaapvaal craton. The average crustal thicknesses for 19 centrally located stations on each of the northern and southern regions of the craton that yielded well-constrained thicknesses were 50.52 ± 0.88 km and 38.07 ± 0.85 km, respectively. In contrast, the corresponding average thicknesses determined from receiver functions were 43.58 ± 0.57 km and 37.58 ± 0.70 km, respectively. The systematically lower values for receiver functions in the northern part of the Kaapvaal craton that was affected by the Bushveld magmatism at 2.05 Ga, suggest that the receiver functions do not enable the petrological crust mantle boundary to be reliably resolved due to variations in composition and metamorphic grade in a mafic lower crust. The Pn times also suggest pervasive azimuthal anisotropy with maximum wavespeeds of about 8.40 km/s at azimuths of about 15° and 217° in the northern and southern regions of the craton, respectively, and minimum wavespeeds of about 8.25 km/s. URI: http://hdl.handle.net/10311/281 Files in this item: 1
Kwadiba_L71_2003.pdf (2.747Mb) -
Maundeni, Z. (Academic Journals, http://www.academicjournals.org, April NaN, 2010)[more][less]
Abstract: This article considers Lesotho’s political history and culture, a political history characterised by rebellious chiefs who had rejected Christianity and who were heavily armed and fought numerous wars against their black and white neighbours. Its argument is that the state’s dysfunctionality in small Lesotho is a result of a political culture and history of armed resistance, producing rebellious political elites who feuded between themselves, against the colonial establishment and against the postcolonial government. It was also a political culture that rejected Christianity, accepted old leaders to die in office and encouraged factionalism. The political parties that emerged from such a political culture were traditionally oriented, radical, dominated by old leaders and were factionalised. Such a society was not easily open to renewal through fresh leaders and borrowed ideas. The article suggests that Lesotho need to come to terms with its political history and to come up with a cultural re-orientation away from traditionalism, rebellion and factionalism. URI: http://hdl.handle.net/10311/585 Files in this item: 1
Maundeni_AJPSIR_2010.pdf (137.1Kb)