Approaches to Transition into Transport Infrastructure Provision and Management

South Africa has been engaging in multibillion rand transport infrastructure planning and construction projects that have the potential to spur the economy into generating significant growth. These mega-projects were conceptualized by government and private sector with the intent of unlocking economic opportunities within the transport infrastructure mainstream. Such initiatives lead to accelerated investments in large infrastructure projects such as for example the Gautrain rapid rail link and other mega projects. The future success of South Africa’s transport economy depends on how the country thinks about unlocking opportunities. This thinking need to consider the manner in which procurement processes are done, and how the delivering of infrastructure takes place in order to create opportunities for funding leveraging existing capacity and resources for such projects. A paradigm shift in thinking about how South Africa invests in large infrastructure projects can create a stable and credible environment in the transport sector that can generate and stimulate local job creation in the future. This paper considers the provision and management of transport infrastructure projects in the long-term and explores the relationships needed between various critical stakeholders for large infrastructure projects to flourish. It is critical that decision-makers embark on clearly crafted plans that outline long-term management of projects that are able to provide a conducive and enabling environment for successfully rolling out transport infrastructure projects.Papers presented at the 38th International Southern African Transport Conference on "Disruptive transport technologies - is South and Southern Africa ready?" held at CSIR International Convention Centre, Pretoria, South Africa on 8th to 11th July 2019

Reorientation-effect measurement of the first 2+ state in 12C : Confirmation of oblate deformation

A Coulomb-excitation reorientation-effect measurement using the TIGRESS γ−ray spectrometer at the TRIUMF/ISAC II facility has permitted the determination of the 〈21 +‖E2ˆ‖21 +〉 diagonal matrix element in 12C from particle−γ coincidence data and state-of-the-art no-core shell model calculations of the nuclear polarizability. The nuclear polarizability for the ground and first-excited (21 +) states in 12C have been calculated using chiral NN N4LO500 and NN+3NF350 interactions, which show convergence and agreement with photo-absorption cross-section data. Predictions show a change in the nuclear polarizability with a substantial increase between the ground state and first excited 21 + state at 4.439 MeV. The polarizability of the 21 + state is introduced into the current and previous Coulomb-excitation reorientation-effect analyses of 12C. Spectroscopic quadrupole moments of QS(21 +)=+0.053(44) eb and QS(21 +)=+0.08(3) eb are determined, respectively, yielding a weighted average of QS(21 +)=+0.071(25) eb, in agreement with recent ab initio calculations. The present measurement confirms that the 21 + state of 12C is oblate and emphasizes the important role played by the nuclear polarizability in Coulomb-excitation studies of light nuclei

Coulomb excitation of and a change in structure approaching N = Z = 40

Background: Nuclei approaching are known to exhibit strongly deformed structures and are thought to be candidates for shape coexistence. In the krypton isotopes, are poorly characterized, preventing an understanding of evolving deformation approaching . Purpose: The present work aims to determine electric quadrupole transition strengths and quadrupole moments of in order to better characterize their deformation. Conclusions: Comparison of measured and values indicates that neutron-deficient () isotopes of krypton are closer to axial deformation than other isotopic chains in the mass region. A continuation of this trend to higher may result in Sr and Zr isotopes exhibiting near-axial prolate deformation. Methods: Sub-barrier Coulomb excitation was employed, impinging the isotopes of krypton on and targets. Utilizing a semiclassical description of the safe Coulomb-excitation process matrix elements could then be determined. Results: Eleven new or improved matrix elements are determined in and seven in . The new value in disagrees with the evaluated value by , which can be explained in terms of deficiencies in a previous Coulomb-excitation analysis

Interventions for orphans and vulnerable children (OVC) at Tapologo HIV/AIDS project in Rustenburg, North West province

Commissioned by the Nelson Mandela Children's Fun

Nucleation and Growth of Silver Nanoparticles by AB and ABC-Type Atomic Layer Deposition

In this work, we report synthesis strategies to produce Ag nanoparticles by AB-type and ABC-type atomic layer deposition (ALD) using trimethylphosphine­(hexafluoroacetylacetonato) silver­(I) ((hfac)­Ag­(PMe₃)) and formalin (AB-type) and (hfac)­Ag­(PMe₃), trimethylaluminum, and H₂O (ABC-type). In situ quartz crystal microbalance measurements reveal a Ag growth rate of 1–2 ng/cm²/cycle by ABC-type ALD at 110 °C and 2–10 ng/cm²/cycle for AB-type ALD at 170–200 °C. AB-type Ag ALD has a nucleation period before continuous linear growth that is shorter at 200 °C. Transmission electron microscopy reveals that AB-type Ag ALD particles have an average size of ∼1.8 nm after 10 cycles. ABC-type Ag ALD particles have an average size of ∼2.2 nm after 20 cycles. With increasing ALD cycles, ABC-type Ag ALD increases the metal loading while maintaining the particle size but AB-type Ag ALD results in the formation of bigger particles in addition to small particles. The ability to synthesize supported metal nanoparticles with well-defined particle sizes and narrow size distributions makes ALD an attractive synthesis method compared to conventional wet chemistry techniques

Probing the Chemistry of Alumina Atomic Layer Deposition Using <i>Operando</i> Surface-Enhanced Raman Spectroscopy

This work demonstrates for the first time the capability of measuring surface vibrational spectra for adsorbates during atomic layer deposition (ALD) reactions using <i>operando</i> surface-enhanced Raman spectroscopy (SERS). We use SERS to study alumina ALD growth at 55 °C on bare silver film-over nanosphere (AgFON) substrates as well as AgFONs functionalized with thiol self-assembled monolayers (SAMs). On bare AgFONs, we observe the growth of Al–C stretches, symmetric C–H and asymmetric C–H stretches during the trimethylaluminum (TMA) dose half-cycle, and their subsequent decay after dosing with H₂O. Al–C and C–H vibrational modes decay in intensity with time even without H₂O exposure providing evidence that residual H₂O in the ALD chamber reacts with −CH₃ groups on AgFONs. The observed Al–C stretches are attributed to TMA dimeric species on the AgFON surface in agreement with density functional theory (DFT) studies. We observe Al–C stretches and no thiol vibrational frequency shifts after dosing TMA on AgFONs functionalized with toluenethiol and benzenethiol SAMs. Conversely, we observe thiol vibrational frequency shifts and no Al–C stretches for AgFONs functionalized with 4-mercaptobenzoic acid and 4-mercaptophenol SAMs. Lack of observed Al–C stretches for COOH- and OH-terminated SAMs is explained by the spacing of Al–(CH₃)_<i>x</i> groups from the SERS substrate. TMA penetrates through SAMs and reacts directly with Ag for benzenethiol and toluenethiol SAMs and selectively reacts with the −COOH and −OH groups for 4-mercaptobenzoic acid and 4-mercaptophenol SAMs, respectively. The high sensitivity and chemical specificity of SERS provides valuable information about the location of ALD deposits with respect to the enhancing substrate. This information can be used to evaluate the efficacy of SAMs in blocking or allowing ALD deposition on metal surfaces. The ability to probe ALD reactions using SERS under realistic reaction conditions will lead to a better understanding of the mechanisms of ALD reactions

High-Resolution Distance Dependence Study of Surface-Enhanced Raman Scattering Enabled by Atomic Layer Deposition

We present a high-resolution distance dependence study of surface-enhanced Raman scattering (SERS) enabled by atomic layer deposition (ALD) at 55 and 100 °C. ALD is used to deposit monolayers of Al₂O₃ on bare silver film over nanospheres (AgFONs) and AgFONs functionalized with self-assembled monolayers. <i>Operando</i> SERS is used to measure the intensities of the Al–CH₃ and C–H stretches from trimethylaluminum (TMA) as a function of distance from the AgFON surface. This study clearly demonstrates that SERS on AgFON substrates displays both a short- and long-range nanometer scale distance dependence. Excellent agreement is obtained between these experiments and theory that incorporates both short-range and long-range terms. This is a high-resolution <i>operando</i> SERS distance dependence study performed in one integrated experiment using ALD Al₂O₃ as the spacer layer and Raman label simultaneously. The long-range SERS distance dependence should make it possible to detect chemisorbed surface species located as far as ∼3 nm from the AgFON substrate and will provide new insight into the surface chemistry of ALD and catalytic reactions