An experimental study of the applicability of flooding phenomena to the dynamic lubrication method of well control

This research investigates the feasibility of the dynamic lubrication method of well control as an alternative to conventional stepwise lubrication. The applicability of flooding phenomena to dynamic lubrication and its use in an optimization method to maximize pumping rates was also investigated. An experimental approach was taken in which experiments were conducted in a 13’ long laboratory apparatus designed to emulate the geometry in a wellhead and also in a full-scale research well. The laboratory experiments were conducted to visually investigate the mechanism of flooding and derive a flooding correlation applicable to this type of system. The full-scale experiments were done to evaluate the dynamic lubrication method, compare it to conventional lubrication, attempt dynamic lubrication at high pumping rates, assess the applicability of flooding as the rate determining phenomenon, and identify any complications encountered during this process. The laboratory tests produced a correlation that was applicable over a range of 3 annular sizes. The equation resembled correlations from previous studies by Richter (1981) and Dempster(1984) and used dimensionless volumetric fluxes as the non-dimensional parameter. The full-scale tests showed that dynamic lubrication was more efficient in removing gas trapped at the wellhead, and reduced the severity of pressure fluctuations inherent in conventional stepwise lubrication. Pumping at constant high rates had an adverse effect on the process. This high pumping rate reduced the rate of accumulation of liquid in the well by 50% when compared to the more conservative pumping rates. The boundary between efficient and inefficient pump rates corresponded well to the correlation from laboratory tests if the relevant dimensions were assumed to be dependent on wellhead geometry. For this wellhead, the casing-casing annulus has a smaller cross sectional area and therefore higher velocities, which logically should control flooding. However, using the casing annulus geometry in the flooding correlation results in incorrect prediction of the onset of flooding unless revised coefficients are used. These revised coefficients were adopted for a proposed preliminary optimization method

The use of visual reasoning by successful mathematics teachers : a case study.

Doctor of Philosophy in Education Studies. University of KwaZulu-Natal, Edgewood 2015.Visualization has become increasingly important in view of the advent of technology which allows us to understand an idea at a single glance. Globally, educationists have been searching for ways to improve learners‘ understanding of mathematics. This has led them to believe that perhaps the focus on the teaching of mathematics needs to change. Contrary to the view that mathematics can only be presented sequentially, another view exists that mathematics is a multimodal discourse where different modes of representation are necessary. Whilst many of our learners experience serious difficulties in mathematics, as testified by the education authorities, there are groups of teachers that attain outstanding results in this subject. In this study I chose to explore how this group of people attain success, whilst engaging with the phenomenon of visual reasoning. The intention of this research was to interpret the kind of meanings that these successful teachers offered in their use of visual reasoning in their practice. Therefore in order to explore the personal, social and learning experiences of these successful mathematics teachers, a case study form of enquiry was employed, with the use of a social constructivist research paradigm, following a qualitative research tradition. A purposeful maximal sampling technique was used to identify five participants. Knowledge is not merely received but constructed by individuals or groups of people who try to make sense of their experiential worlds. This study sought to explore the ways in which these successful teachers constructed and interpreted the knowledge that they passed onto their learners, using the phenomenon of visual reasoning. Furthermore, constructivism as a research paradigm is characterised by plurality and multiple perspectives. Taking this into account, Attribution Theory, Gardner‘s Multiple Intelligences Theory and Situated Cognition Theory were used as a lens to explain the complex phenomena of visual reasoning and successful teaching. The results of the study showed that all the participants were actively engaged in using visual reasoning as a pedagogic practice in their mathematics classrooms. Explanations for their actions in terms of using visual reasoning resonated with the literature and the theoretical frameworks that were used

Recurrent subacute visual loss presenting in a 52-year-old Caucasian woman with chronic relapsing inflammatory optic neuropathy: a case report

<p>Abstract</p> <p>Introduction</p> <p>Chronic relapsing inflammatory optic neuropathy is a recently described form of recurrent isolated subacute optic neuropathy. The condition is highly responsive to systemic steroid treatment and prone to relapse on steroid withdrawal. A complete work up for demyelination, autoimmune disease and sarcoidosis must be made before considering chronic relapsing inflammatory optic neuropathy.</p> <p>Case presentation</p> <p>We describe the case of a 52-year-old Caucasian woman who presented with isolated subacute optic neuropathy. There was no evidence of demyelination, autoimmunity or sarcoidosis. There was an abrupt and prompt response to systemic corticosteroids and a relapse of the condition on steroid withdrawal.</p> <p>Conclusions</p> <p>Chronic relapsing inflammatory optic neuropathy requires careful consideration and differentiation from demyelinating optic neuritis and ischemic optic neuropathy since the treatment is different and the outcome without treatment is likely to be poor. The importance of identifying these patients has considerable clinical implications as the condition is highly responsive to steroids.</p

Spread of multi drug resistant tuberculosis (MDR) including extensively drug resistant turberculosis (XDR TB), in rural KwaZulu-Natal.

Thesis (M.Med.)-University of KwaZulu-Natal, Durban, 2011.Mycobacterium tuberculosis (MTB) is an airborne pathogen that is easily transmitted from person to person. An intact immune system prevents the organism from causing disease in most individuals. In South Africa, the prevalence of human immunodeficiency virus (HIV) has reached astronomical levels and is now fuelling the tuberculosis (TB) epidemic. Drug resistant MTB strains combined with a weakened host immune system is a lethal combination. Multi-drug resistant (MDR) including extensively drug resistant (XDR) tuberculosis is on the increase, with Tugela Ferry in KwaZulu-Natal South Africa, reporting the largest cluster of XDR cases in the world. It is unknown whether a single clone of the drug resistant strain is circulating in this area or whether there are multiple strains at play. Using 2 complementary genotyping methods, we showed that the MDR strains present are the result of clonal spread associated with the F28 family, as well as de novo resistance which manifests as unique patterns. The XDR epidemic in Tugela Ferry is the result of clonal spread of a strain belonging to the F15/LAM4/KZN family

MYOCARDIAL INFARCTION IN A YOUNG PATIENT WITH METHYLENE TETRAHYDROFOLATE REDUCTASE (MTHFR) GENE MUTATION

We report a case of a 40 year old female patient who presents with chest pain and is diagnosed with a inferior myocardial infarction (MI) and when tested she was found to be heterozygous (C677T) for Methylene Tetrahydrofolate Reductase (MTHFR) gene mutation. The patient was stopped from using the OCP and was started on life-long oral daily folic acid supplementation. Screening of her siblings led to the discovery that her two sisters were both homozygous for MTHFR deficiency. This case clearly illustrates that we as clinicians must look beyond the box and not just treat common conditions like CHD. When the risk factors do not add up, we must go in search of an identifiable cause that can have future benefit for the patient and other family members

GT2011-45214 EFFECTS OF ROTATING STALL ON AN AXIAL FAN DESIGN

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Increasing Drug Resistance in Extensively Drug-Resistant Tuberculosis, South Africa

We expanded second-line tuberculosis (TB) drug susceptibility testing for extensively drug-resistant Mycobacterium tuberculosis isolates from South Africa. Of 19 patients with extensively drug-resistant TB identified during February 2008–April 2009, 13 (68%) had isolates resistant to all 8 drugs tested. This resistance leaves no effective treatment with available drugs in South Africa

PROMOTING PRO-ENVIRONMENTAL BEHAVIORS: THE INFLUENCE OF ENVIRONMENTAL EDUCATION AND ENVIRONMENTAL AWARENESS ON LITTERING WITHIN TWO ECOTOURISM DESTINATIONS IN TRINIDAD

The purpose of this study was to investigate the influence of environmental education and awareness on littering behavior within two ecotourism destinations (Asa Wright Nature Center and Rio Seco Waterfall). Furthermore, an attempt was made to produce a model that identified and explained the possible relationships between various constructs that affected the pro-environmental behavior of “not littering by ecotourists at the two ecotourism destinations. The conceptual background of this research venture was derived from the Theory of Planned Behavior and was further informed by the Grounded Theory. A mixed methods approach including both a qualitative phase and quantitative phase was utilized for the relevant data collection and analyses in this study. The qualitative data were collected from informal interviews with a total of two managers and six tour guides. Data analysis through a thematic coding procedure utilized the results to inform a final questionnaire design for quantitative data collection. Subsequently, quantitative data were collected via the administration of survey questionnaires to a total of 404 ecotourist participants at the Asa Wright Nature Center and the Rio Seco Waterfall. Descriptive statistics and path analyses were executed for analysis of the quantitative data. Findings indicated the hypothesized significance of ecotourists practicing more pro-environmental behavior based on their level of environmental awareness

CAMPSITE IMPACTS IN WILDERNESS VS. VISITOR WILLINGNESS TO PAY FOR ITS PRESERVATION

Wilderness areas provide a wide array of quality nature experiences including primitive recreational opportunities in a primeval condition. However, a lot of these ecological and pristine sites suffer from disturbance and environmental degradation by the exhaustive human recreational use on campsites. Most of the impacts associated with camping gradually become a critical concern since they can be devastating to a wilderness environment and the affiliated experience. This study employed the contingent valuation method to determine peoples\u27 willingness to pay for the preservation of the Panther Den Wilderness if campsites were restricted /limited, and to estimate an economic value of non-market goods and services affiliated to the preservation and use values of the Panther Den Wilderness. A Contingent valuation questionnaire was administered to gather information on the respondent\u27s intentions and to determine what they would be willing to pay under a hypothetical scenario. Moon\u27s WTP model estimated the willingness to pay relationship with a set of explanatory and socio-demographic variables including bid sizes, miles traveled, recreation times, campsite impacts observed, age, gender, and education. Results revealed that there was a clear relationship between the respondents\u27 willingness to pay, the pre-determined bid-size/fee level, and the distance traveled to the Panther Den Wilderness, hence; the correlation between the variables was highly significant. The estimated mean willingness to pay value for the preservation of the Panther Den Wilderness was $9.56 per visitor. Overall, the estimated results and mean willingness to pay value served as the interpretation of an assessment which clearly revealed that outdoor recreation users were willing to pay a user fee for the preservation of the Panther Den Wilderness regardless of campsite limitations or restrictions