Noodtoestand en die aksie van afhanklikes: Maimela v Makhado Municipality 2011-5-20 Saaknr 269/10 (HHA)

Uit teks: Die eerste eiser (M) en ene D, die oorlede man van die tweede eiser (P), is deur skote getref wat afgevuur is deur die tweede verweerder (N), ’n werknemer van die eerste verweerder, ’n munisipaliteit. M het die skoot oorleef terwyl D gesterf het weens die wond wat hy opgedoen het. Die eisers stel ’n skadevergoedingseis teen die verweerders in, M weens die beserings wat hy opgedoen het, en P weens die verlies van onderhoud namens haar en haar vier kinders weens die dood van D met wie sy ingevolge ’n gewoonteregtelike huwelik getroud was. Die munisipaliteit word middellik aangespreek omdat N na bewering in die loop van sy diensbetrekking opgetree het, en N in persoonlike hoedanigheid. Die verweerders beroep hulle op noodweer en noodtoestand as verweersgronde

Persistent pain following ankle sprain: Bilateral accessory soleus muscles

Persistent pain following ankle sprain remains a difficult diagnostic and management dilemma. We report a 22 year old rugby player who presented with a persistent painful left ankle following a minor ankle sprain. After examination and imaging investigations, a symptomatic accessory soleus muscle was diagnosed on the left ankle, and an asymptomatic accessory soleus muscle on the right

In-depth characterisation of metal-support compounds in spent Co/SiO2 Fischer-Tropsch model catalysts

Only little is known about the formation and morphology of metal-support compounds (MSCs) in heterogeneous catalysis. This fact can be mostly ascribed to the challenges in directly identifying these phases. In the present study, a series of Co/SiO2 model catalysts with different crystallite sizes was thoroughly characterised with focus on the identification of cobalt silicate, which is the expected metal-support compound for this particular catalyst system. The catalysts were exposed to simulated high conversion Fischer-Tropsch environment, i.e. water-rich conditions in the presence of hydrogen. The transformation of significant amounts of metallic cobalt to a hard-to-reduce phase has been observed. This particular MSC, Co2SiO4, was herein identified as needle- or platelet-type cobalt silicate structures by means of X-ray spectroscopy (XAS) and high-resolution scanning transmission electron microscopy (HRSTEM) in combination with elemental mapping. The metal-support compounds formed on top of fully SiO2-encapsulated nanoparticles, which are hypothesised to represent a prerequisite for the formation of cobalt silicate needles. Both, the encapsulation of cobalt nanoparticles by SiO2 via creeping, as well as the formation of these structures, were seemingly induced by high concentrations of water

Characterisation of the multiphase fluid dynamics of the CoarseAIR™ fluidised bed flotation cell using the Large Modular Array (LaMA) for positron emission particle tracking (PEPT)

Fluidised bed flotation cells (FBFCs) present a compelling solution for coarse particle flotation, enabling an increase in the target particle size in comminution circuits, with the corresponding energy savings. Despite their potential and strong industrial interest, the three-phase fluid dynamics of large-scale FBFCs remain unexplored due to measurement complexities and size restrictions. This paper presents the first quantification of the fluid dynamics of the CoarseAir™-100, a 2 m tall laboratory-scale FBFC. Measurements were obtained using positron emission particle tracking (PEPT), a non-invasive technique that tracks the motion of a radiolabelled tracer. Leveraging the Large Modular Array (LaMA) PEPT system, consisting of 48 buckets, each housing four detector blocks, this study is the largest PEPT experiment to date. Particle tracks of hydrophobic and hydrophilic tracers were obtained under different fluidisation and airflow rates. Hydrophobic tracers exhibited buoyant behaviour despite their large size of up to 700 μm, while hydrophilic tracers engaged in recirculation patterns with rapid downward motion near the walls. The intricate motion of particles in the lamella plates was experimentally quantified, revealing an average path tortuosity of 7.3, providing essential information for design. These results represent a major advance in our understanding of fluidised bed flotation cells, contributing to the refinement of design and scale-up strategies for FBFCs

Characterisation of solid hydrodynamics in a three-phase stirred tank reactor with positron emission particle tracking (PEPT)

It is challenging to measure the hydrodynamics of stirred tank reactors when they contain multiphase flows comprising liquid, gas bubbles and particles. Radioactive particle tracking techniques such as positron emission particle tracking (PEPT) are the only established techniques to determine internal flow behaviour due to the inherent opacity and density of fluid and the vessel walls. The profiles of solids flow are an important tool for robust reactor design and optimisation and offer insight into underlying transport processes and particle–fluid–bubble interactions for applications such as froth flotation. In this work, measurements with PEPT were performed with two tracer particles differing in surface hydrophobicity to characterise the solids hydrodynamics in a baffled vessel agitated with a Rushton turbine. The location data from PEPT were averaged with time to estimate the probability density function (PDF) of particle velocity in individual voxels. The peaks of these voxel distributions were used to produce profiles of solids flow in different azimuthal and horizontal slices. Bimodal vertical velocity distributions were observed in the impeller radial jet which suggest the particles experienced trajectory crossing effects due to inertia. Statistical tests were performed to compare the velocity distributions of the hydrophilic and hydrophobic tracer particles, which indicated similar average flow behaviour in the liquid or pulp phase of the vessel and differences near the air inlet, in the impeller discharge stream and pulp–froth interface. With tracers designed to represent gangue and valuable mineral species, the differences in velocity reveal interactions such as bubble–particle attachment and entrainment

A retrospective time trend study of firearm and nonfirearm homicide in Cape Town from 1994 to 2013

Background. Gunshot injuries from interpersonal violence are a major cause of mortality. In South Africa (SA), the Firearms Control Act of 2000 sought to address firearm violence by removing illegally owned firearms from circulation, stricter regulation of legally owned firearms, and stricter licensing requirements. Over the last few years, varied implementation of the Act and police corruption have increased firearm availability.Objectives. To investigate whether changes in firearm availability in SA were associated with changes in firearm homicide rates.Methods. This was a retrospective time trend study (1994 - 2013) using postmortem data. Time trends of firearm and non-firearm homicide rates were analysed with generalised linear models. Distinct time periods for temporal trends were assigned based on a priori assumptions regarding changes in the availability of firearms.Results. Firearm and non-firearm homicide rates adjusted for age, sex and race exhibited different temporal trends. Non-firearm homicide rates either decreased or remained stable over the entire period. Firearm homicide increased at 13% annually from 1994 through 2000, and decreased by 15% from 2003 through 2006, corresponding with changes in firearm availability in 2001, 2003, 2007 and 2011. A 21% annual increase in firearm homicide after 2010 coincided with police fast-tracking new firearm licence applications. Cape Town’s coloured population experienced a significantly greater increase than other population groups following additional exposure to illegal firearms from 2007.Conclusions. The strong association between firearm availability and homicide, and the reversal of a decreasing firearm homicide trend during a period of lax enforcement, provide further support for the association between reduced firearm homicide and stricter regulation

Numerical simulation of scour below pipelines using flexible mesh methods

Evaluating bed morphological structure and evolution (specifically the scoured bed level) accurately using numerical models is critical for analyses of the stability of many marine structures. This paper discusses the performance of an implementation within Fluidity, an open source, general purpose, computational fluid dynamics (CFD) code, capable of handling arbitrary multi-scale unstructured tetrahedral meshes and including algorithms to perform dynamic anisotropic mesh adaptivity. The flexibility over mesh structure and resolution that these capabilities provide makes it potentially highly suitable for coupling the structural scale with larger scale ocean dynamics. In this very preliminary study the solver approach is demonstrated for an idealised scenario. Discontinuous Galerkin finite-element (DG-FEM) based discretisation methods have been used for the hydrodynamics and morphological calculations, and automatic mesh deformation has been utilised to account for bed evolution changes while preserving the validity and quality of the mesh. In future work, the solver will be used in three-dimensional impinging jet and other industrial and environmental scour studies

Hydrodynamics in a three-phase flotation system - fluid following with a new hydrogel tracer for Positron Emission Particle Tracking (PEPT)

Understanding the hydrodynamics of three-phase stirred tanks, such as froth flotation cells, is paramount for the characterisation of turbulence, stability and performance. Although positron emission particle tracking (PEPT) is known for its effectiveness in measuring the hydrodynamics of particles in opaque, high solid content systems, it has not been widely used for characterising the liquid phase. This work presents a new, neutrally buoyant, alginate hydrogel tracer, designed to emulate the density of the liquid phase, which is suitable for high-speed tracking with PEPT. PEPT experiments were conducted in a bench-scale flotation cell, comparing the new tracer to ion-exchange resin tracers previously used in this system. Results showed statistically significant differences in pathlines, residence time and velocity distribution among the tracers. Moreover, the hydrodynamics of the new tracer agree with existing CFD predictions for the liquid phase. This methodology enables the comprehensive study of relative flow behaviour in complex multiphase systems