Faculty of Natural Sciences: Recent submissions
Now showing items 2361-2380 of 2527
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The role of ground water in Sub-Saharan Africa
(Wiley-Blackwell, 2010)Although water resources managers speak of a water crisis in Africa, the management of ground water has to date not featured strongly in national and regional African water agendas. Examination of the physical environment of ... -
Review: groundwater management and groundwater/surface-water interaction in the context of South African water policy
(Springer Verlag, 2011)Groundwater/surface-water interaction is receiv¬ing increasing focus in Africa due to its importance to ecologic systems and sustainability. In South Africa's 1998 National Water Act (NWA), water-use licenses, including ... -
A three-tier approach to protect groundwater resources in South Africa
(Water Research Commission, 1995)The quality of groundwater is affected by many activities occurring on the surface of the earth. A pro-active protection approach is required to avoid the costly and technology difficult exercise of groundwater remediation. ... -
Borehole dilution experiment in a Karoo aquifer in Bloemfontein
(Water Research Commission, 1997)This paper shows that a borehole dilution experiment using common salt is a useful technique for better understanding of some hydrogeological features of a fractured aquifer. A sense of such tracer experiments was performed ... -
Estimation of recharge using a revised CRD method
(Water Research Commission, 2001)The cumulative rainfall departure (CRD) method, based on the water-balance principle, is often used for mimicking of water level fluctuations. Because of its simplicity and minimal requirement of spatial data, the CRD ... -
Groundwater discharges to aquatic ecosystems associated with the Table Mountain Group (TMG) aquifer: a conceptual model
(Water Research Commission, 2008)This paper reports on a conceptual model that was developed to describe the different groundwater discharge ‘types’ from the Table Mountain Group (TMG) aquifer, that contributes to the different components of the flow ... -
Snow impact on groundwater recharge in Table Mountain Group aquifer systems with a case study of the Kommissiekraal River catchment South Africa
(Water Research Commission, 2005)Snowmelt in the mountainous areas of the Table Mountain Group (TMG) in South Africa is believed to be one of sources of groundwater recharge in some winter seasons. This paper provides a scientific assessment of snow ... -
An extensive search for rapid optical variability in ultracool dwarfs
(Oxford University Press, 2013)In this paper, a summary of optical time-series photometry of 125 ultracool dwarfs is given. The observing strategy was to monitor each object continuously for 2–3 h in order to ascertain whether itwas rapidly variable. ... -
Book review: urban geology
(Springer Verlag, 2012) -
A water balance approach to the sustainable management of groundwater in South Africa
(Water Research Commission, 2000)The water balance approach, based on the principles of conservation of mass, is applied to the issue of sustainable groundwater management in South Africa, incorporating the ethos of the National Water Act of 1998, ... -
Application of the rainfall infiltration breakthrough (RIB) model for groundwater recharge estimation in west coastal South Africa
(Water Research Commission, 2013)Recharge estimation in arid and semi-arid areas is very challenging. The chloride mass balance method applied in western South Africa fails to provide reliable recharge estimates near coastal areas. A relationship between ... -
Time series models of three sets of RXTE Observations of 4U 1543-47
(Oxford University Press, 2013)The X-ray nova 4U 1543−47 was in a different physical state (low/hard, high/soft, and very high) during the acquisition of each of the three time series analyzed in this paper. Standard time series models of the ... -
A tensor approach to the estimation of hydraulic conductivities in Table Mountain Group aquifers of South Africa
(Water Research Commission, 2006)Based on the field measurements of the physical properties of fractured rocks, the anisotropic properties of hydraulic conductivity (HC) of the fractured rock aquifer can be assessed and presented using a tensor approach ... -
UBV(RI)C JHK observations of Hipparcos-selected nearby stars
(Oxford University Press, 2010)We present homogeneous, standardized UBV(RI)C photometry for over 700 nearby stars selected on the basis of Hipparcos parallaxes. Additionally, we list JHK photometry for about half of these stars, as well as L photometry ... -
A hydrogeomorphological approach to quantification of groundwater discharge to streams in South Africa
(Water Research Commission, 2002)In South Africa, the flow requirements for maintaining the normal functioning of aquatic ecosystems is termed the “ecological reserve”, and these should be determined when a licence application for water allocation is ... -
Capture zone simulation for boreholes located in fractured dykes using the linesink concept
(Water Research Commission, 2002)Delineation of capture zones for groundwater source protection is normally performed by using numerical codes which are based on the porous medium flow equation. However, boreholes are often sited in or along permeable ... -
Is there evolution in the infrared Tully–Fisher relation? Comparing two linear regressions
(Oxford University Press, 2009)In a recent paper, Puech and co-workers compared K-band Tully–Fisher relations derived for nearby and distant galaxies, respectively. They concluded that the two relations differ, and deduced that there is evolution in ... -
Time series photometry of the nearby brown dwarf DENIS-P J0041353-562112
(Oxford University Press, 2011)DENIS-P J0041353−562112 is a brown dwarf, with a spectral type of M7.5, which may be younger than 20 Myr. On the basis of its Hα emission-line asymmetry, it has been suggested that the object is accreting material. If ... -
The detailed forms of the LMC Cepheid PL and PLC relations
(Oxford University Press, 2007)Possible deviations from linearity of the Large Magellanic Cloud Cepheid period–luminosity (PL) and period–luminosity–colour (PLC) relations are investigated. Two data sets are studied, respectively from the Optical ...