Black economic empowerment in the South African mining industry : a case study of Exxaro Limited

The original publication is available at http://reference.sabinet.co.za/sa_epublication/busmanThis paper explores some of the key challenges and opportunities in the implementation of the broad-based black economic empowerment (BBBEE) deal of Kumba Resources, which subsequently led to the formation of Exxaro Limited, a large black-owned mining conglomerate in South Africa. Qualitative data were collected through in-depth interviews with a sample of 11 leaders involved directly in the deal. The data were content-analysed and the findings suggested that BEE transactions faced numerous challenges, including finding sustainable funding, securing suitable investors, merging various cultures, dealing with fronting and leadership, and planning management and leadership succession. The study concluded that the deal led successfully to both the equitable transfer of ownership and management and to the control of financial and economic resources to a wider base of the black population. However, several malpractices were identified which may have impeded the process of achieving the intended outcomes. The article provides recommendations, indicates limitations and proposes a way forward.Publishers' versio

Nanoscale magnetic structure of ferromagnet/antiferromagnet manganite multilayers

Polarized Neutron Reflectometry and magnetometry measurements have been used to obtain a comprehensive picture of the magnetic structure of a series of La{2/3}Sr{1/3}MnO{3}/Pr{2/3}Ca{1/3}MnO{3} (LSMO/PCMO) superlattices, with varying thickness of the antiferromagnetic (AFM) PCMO layers (0<=t_A<=7.6 nm). While LSMO presents a few magnetically frustrated monolayers at the interfaces with PCMO, in the latter a magnetic contribution due to FM inclusions within the AFM matrix was found to be maximized at t_A~3 nm. This enhancement of the FM moment occurs at the matching between layer thickness and cluster size, where the FM clusters would find the optimal strain conditions to be accommodated within the "non-FM" material. These results have important implications for tuning phase separation via the explicit control of strain.Comment: 4 pages, submitted to PR

Preparation of Electronics Grade Bismuth, Antimony, Tellurium, Cadmium and Zinc by Vacuum distillation and Zone refining

Bismuth, antimony, tellurium, cadmium and zinc, in their ultra-high purity forms (99.99 to 99.999%), have recently acquired special significance in the electronics industry. Several methods such as precipitation, crysta-llization, electrolysis, distillation, ion-exchange, sol-vent extraction, zone melting, etc. are available for the preparation of such high purity and electronics grades material

Annihilation Diagrams in Two-Body Nonleptonic Decays of Charmed Mesons

In the pole-dominance model for the two-body nonleptonic decays of charmed mesons $D \rightarrow PV$ and $D \rightarrow VV$, it is shown that the contributions of the intermediate pseudoscalar and the axial-vector meson poles cancel each other in the annihilation diagrams in the chiral limit. In the same limit, the annihilation diagrams for the $D \rightarrow PP$ decays vanish independently.Comment: 9 pages (+ 3 figures available upon request), UR-1316, ER-40685-766, IC/93/21

Comments on black holes I: The possibility of complementarity

We comment on a recent paper of Almheiri, Marolf, Polchinski and Sully who argue against black hole complementarity based on the claim that an infalling observer 'burns' as he approaches the horizon. We show that in fact measurements made by an infalling observer outside the horizon are statistically identical for the cases of vacuum at the horizon and radiation emerging from a stretched horizon. This forces us to follow the dynamics all the way to the horizon, where we need to know the details of Planck scale physics. We note that in string theory the fuzzball structure of microstates does not give any place to 'continue through' this Planck regime. AMPS argue that interactions near the horizon preclude traditional complementarity. But the conjecture of 'fuzzball complementarity' works in the opposite way: the infalling quantum is absorbed by the fuzzball surface, and it is the resulting dynamics that is conjectured to admit a complementary description.Comment: 34 pages, 6 figures, v3: clarifications & references adde

Transition from internal to external oxidation in indium-silver alloys

The kinetics of oxidation of In-Ag alloys of 5,10, and 15 at. % indium have been studied on a vacuum microbalance. The 15 at. % indium alloy oxidizes externally and the 5 at. % alloy internally. A plot of logarithm of the parabolic oxidation rate, kp, versus reciprocal of the absolute temperature for 10 at. % indium alloy gives two intersecting straight lines corresponding to the energies of activation of 23 and 39.6 kcal/mole for the oxidation below and above 600&#176;C respectively. These are comparable to the energies of activation of 23 kcal/mole for the internal oxidation of 5 at. % indium alloy and 40 kcal/mole for the external oxidation of 15 at. % indium alloy. The rate-controlling step in the external oxidation of 15 at. % indium alloy is the diffusion of indium through the alloy. Photomicrographs of the cross sections of the oxidized foils of these alloys confirm the conclusions derived from the kinetic data

Precise time and frequency intercomparison between NPL, India and PTB, Federal Republic of Germany via satellite symphonie-1

A time and frequency intercomparison experiment conducted using Earth stations in New Delhi, India and Raisting, FRG is described. The NPL clock was placed at New Delhi Earth Station and the Raisting Clock was calibrated with PTB/Primary standard via LORAN-C and travelling clocks. The random uncertainity of time comparisons, represented by two sample Allan Variance sigma (30 seconds), was less than 10 nanoseconds. The relative frequency difference between the NPL and Raisting Clocks, SNPL, RAIS, as measured over the 44 days period was found to be -15.7 x 10 to the -13th power. The relative frequency difference between PTB Primary Standard and Raisting Clock, SPTB, RAIS, during this period, was measured to be -22.8 x 10 to the -13th power. The relative frequency difference between NPL clock and PTB Primary Standard, SNPL, PTB, thus, is +7.1 x 10 to the -13th power. The clock rate (UTC, India) of +7.1 + or - 0.5 x 10 to the -13th power, agrees well with that obtained via VLF phase measurements over one year period and with USNO travelling clock time comparisons made in September, 1980