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Made available in DSpace on 2014-10-09T12:54:00Z (GMT). No. of bitstreams: 0 / Made available in DSpace on 2014-10-09T14:09:21Z (GMT). No. of bitstreams: 1 12436.pdf: 2191865 bytes, checksum: 12b10ebed00b6647c2de939f5f567b1d (MD5) / Tese (Doutoramento) / IPEN/T / Escola Politecnica, Universidade de Sao Paulo - POLI/USP

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M.A. / Emergence of informal settlements on vacant lands in urban areas results from intuition and political decisions, and sometimes cultural background. So any available vacant land is used for settlement development and dwelling sites. An informal settlement named after Elias Motsoaledi, a political activist of the African National Congress (ANC), was developed in the south-western part of the city of Johannesburg in 1993. Motsoaledi informal settlement was established on a vacant piece of land where there are overhead power lines. Motsoaledi community members that have their dwellings in close proximity and even underneath overhead power lines are exposed to an environment that is surrounded by electrical magnetic fields (EMFs). There are no reported cases of biological and health consequences that have been caused by EMFs as yet. This study aims to focus on the health aspect of persons who have their dwelling in the vicinity of the overhead power lines in Motsoaledi. The high levels of EMFs around Motsoaledi is further excelerated by the zinc structures that are conductive to electricity and may result in electrocution for dwellers that are in the direct vicinity of overhead power lines. Longer exposure to athermal conditions may result in bio-effects and lead to changes in human health. Furthermore, effects from EMFs are possible electrocution, often causing immediate death of persons and destruction of property. Due to the lack of proper planning of informal settlements, such settlements become vulnerable to potential environmental hazards such as the destruction of structures. This study hopes to identify the plight of a particular informal settlement, namely, Motsoaledi as an isolated case to reflect dire conditions of most of the informal settlements around the country.

No description available.

Scientific views on EMF radiation dosimetry and models increasingly suggest that even a tiny increase in the incidence of diseases resulting from exposure to EMF radiation could have broad¹ implications for public health, social accounting and the economy. In South Africa (SA) there is no national EMF radiation exposure protection standard, statutory monitoring or regulations. Multinational High Court deliberations indicate the need for public interest EMF radiation exposure protection standards in South Africa. Domestic citizens, academics, as well as regulatory and legislative practitioners, are unable to effectively monitor and investigate EMF radiation exposure emissions from infrastructure sources, because industries refuse to provide the required data. Industries have, since 2003, continually obstructed access to the data and the establishment of a national EMF radiation standard, citing that it would be in conflict with their strategic economic interests. The demonstration of a public interest override (PIO) function is legislatively required to gain access to the required data. This study constructed (1) a framework and (2) a model to perform test simulations against the (3) PIO criteria to demonstrate a PIO function and tested one PIO simulation scenario. Testing the PIO scenario firstly required the construction of a public interest framework, drawing input from multiple disciplines. The framework literature review used systematic case law and scientific-technical analysis whilst the framework science sought to understand the connections, feedbacks, and trajectories that occur as a result of natural and human system processes and exchanges. The EMF radiation exposure system functions to support human wellbeing needs and to explore the benefits and losses associated with alternative futures with the goal to uncover the current and future limits thereof. In the second instance a HYGEIA² model was selected as a base investigation and forecast simulation tool. The study had to uncover the key attributes and parameters necessary to construct and to run successful EMF radiation exposure simulations. Thereafter the HYGEIA model was modified to specifically identify and evaluate EMF radiation exposure hazard conditions. Through subsequent simulation runs, the constructed framework was then tested. Requested anthroposphere information was synthesized within a systems model to forecast ecosystem services and human-use dynamics under alternative scenarios. The simulation used the model, the model references and the framework for guidelines, thus allowing multiple simulation / demonstration runs for different contexts or scenarios. The third step was the construction of a PIO checklist which guides criteria testing and provides a means of gaining pertinent information for further studies, based on this dissertation. Framework EMF radiation policy inputs into the model were intersected with identified vulnerable area facilities which were selected based on international criteria. The research output revealed potential EMF radiation violations which served as system feedback inputs in support of a demonstrated PIO function. The research recommends that the identified EMF radiation exposure violations of public health undergo a Promotion of Access to Information Act (PAIA) judicial review process to confirm the research findings. The judicial qualification of a PAIA PIO function of ‘substances released into the environment’ and ‘public safety or environmental risk’ would enable access to EMF radiation emissions data essential to future studies.

In electronic flat bands the electron kinetic energy is quenched and dominated by interaction and correlated states can emerge. These many-body collective modes are not only interesting enigmas to solve, but may also lead to real-life applications. This thesis studies correlated states in graphene, a tunable system that can be programmed by ex- ternal parameters such as electric field. Two types of graphene flat bands are examined. One, highly degenerate and discreet Landau levels created by external magnetic field. Two, moirè flat bands created by relative crystalline twist between graphene layers. Correlated states are studied with transport measurements. The results were measured in dual-gated graphite/Boron nitride encapsulated graphene heterostructures with very low disorder. The high quality of the heterostructure is showcased by ballistic electron optics including nega- tive refraction across a gate-defined pn junction. In the first type of flat band — a partially filled Landau level — the competition of electrons solid states and fractional quantum Hall liquid manifests as reentrant quantum Hall effect, with a valley and spin hierarchy unique to graphene. Alternatively, in the flat bands arising from moiré superlattices, we explore two tuning knobs of correlated states. In twisted bilayer graphene, the band width are tuned by changing interlayer hybridization via pressure. The resulting superconducting and correlated insulator states can be restored outside of a narrow range of twist angles near 1.1 degrees. New fermi surfaces also form at commensurate fillings of the flat band with reduced degeneracy. In twisted monolayer-bilayer graphene, we find extraordinary level of control and tunability because of the low symmetry. With perpendicular electric field, the system can alternate among correlated metallic and insulating states, as well as topological magnetic states. The magnetization direction can be switched purely with electrostatic doping at zero magnetic field.

No description available.