The research, investigating how a selected group of former BETD graduates understand and implement the theory of reflective practice, is a qualitative case study carried out in the Kavango region of Namibia. The study was shaped by one of the major policy emphases in Namibia’s post independence teacher education reform process - that of developing reflective teachers who actively participate in curriculum planning and take educational decisions based on their own judgment. A basic assumption underlying the study is that effective educational practice is dependent on practitioners thinking about what they are doing and acting on their reflections to improve practice. The study found that a fundamental problem preventing these teachers from implementing reflective practice in accordance with the Namibian educational reform process, is that the participating teachers neither understand the exact meaning of reflective practice nor do they have a common or shared view of the concept, in spite of their common qualifications. A key contributing factor to their problems withimplementing reflective practice is the lack of a deep understanding of the reform epistemology and pedagogy revealed by the three former BETD graduates selected for the research. These are the teachers referred to in the first paragraph: The first teacher is Helena, a teacher at Duduva primary school, the second teacher is Kalishe, also teaching at the same school as Helena and the third teacher is Darius at Ntja Junior secondary school. The qualitative approach employed for the study served to illuminate and highlight specific issues related to the implementation of reflective practice that will be of considerable value for the researcher in her capacity as a teacher educator. These included among others: • The teacher’s need for an understanding of the key principles on which reflection is based and how to translate these into practice. • The need for teachers to have a clear understanding of the role that learners play in the reflective process. • The need to revisit the Basic Education Teacher Diploma (BETD) education programme, because for teachers to reflect they need a sound subject knowledge on which to base their judgments. These aspects, as well as the identification of the factors in the school system that contribute to the failure of reflective practice, provide a foundation for finding real solutions to the problems identified.

This diploma thesis deals with battery charging. The thesis describes qualities and possi-bilities of lithium battery charging. The charger is independent on the input voltage and recharges batteries carefully. Due to a careful recharging process it is needed to measure the voltage at various cells of the battery and then balance this voltage. Since the charger is to be implemented in a robot, it is needed to switch the operation from an external source and the battery. The first part of the project deals with qualities of batteries and the way of their recharging. In the second part I design an individual blocks charger. In the third part I deal with a communication with a computer charger and data visualization. And in the last part I designed a program for the charger.

Field, greenhouse and laboratory experiments were implemented to investigate the effects of auxin herbicides on growth and yield of cotton in glyphosate based systems. Field experiments evaluated the effect of rate and timing of dicamba or 2,4-D exposure when applied in glyphosate-resistant cotton. Increasing rates of either dicamba or 2,4-D resulted in increased injury and yield reductions. Initial injury symptomology was similar for cotton exposed at vegetative and reproductive stages. When cotton was exposed to auxin herbicides during vegetative growth, injury increased with time, while foliar injury during reproductive growth was stagnant and often decreased with time. Subsequently, the strongest correlations to yield loss and injury were from later evaluations of vegetative timings. Recovery from injury due to auxin herbicide exposure was dependent upon favorable environmental conditions; however, recovery was often superficial and masked significant yield loss. Greenhouse studies evaluated the impact of the diglycolamine dicamba salt on the movement of 14C radio-labeled potassium salt glyphosate in barnyardgrass and johnsongrass. Increasing glyphosate rate increased total absorption of glyphosate in both species. Total absorption of glyphosate was not impacted by the presence of dicamba, for either johnsongrass or barnyardgrass. Dicamba did not consistently alter the translocation of glyphosate in johnsongrass; however, dicamba did reduce glyphosate translocation in barnyardgrass. Total amount of translocated glyphosate was 2.6 to 4.6% and 3.8 to 6.8% of applied in barnyardgrass and johnsongrass, respectively. Reduced translocation in barnyardgrass was a result of increased glyphosate accumulation in the distal portion of the treated leaf. Increasing the rate of glyphosate did overcome the dicamba induced antagonism; however, altered translocation of glyphosate has been documented to be a precursor to herbicide resistance.

Studies were conducted to evaluate the effects of trinexapac-ethyl (TE) on height reduction, tillering, chlorophyll content, color, flowering, and root development of three ornamental grasses: Calamagrostis ×acutiflora 'Karl Foerster', Miscanthus sinensis 'Variegatus', and Pennisetum ×advena 'Rubrum'. Two applications of TE reduced height in all grasses and improved chlorophyll content in C. 'Karl Foerster' while delaying flowering in M. 'Variegatus' and P. 'Rubrum'. Tillering was slightly increased in M. 'Variegatus' with two TE applications. Shoot dry weight (SDW) and root dry weight (RDW) were reduced in C. 'Karl Foerster', SDW was reduced in P. 'Rubrum' and SDW and RDW were unaffected by applications of TE in M. 'Variegatus'. TE is effective for growth control in ornamental grass production systems; however, the results are species specific and should be tested further before widespread use on other ornamental grass species.

Studies were conducted in the field from 2020-2021 in peanut and cotton to optimize peanut growth and yield through prohexadione calcium application methods as well as weed control through increasing herbicide sites of action. These studies were established on multiple on-farm and small-plot locations in Mississippi. Prohexadione calcium studies concluded that following application of prohexadione calcium effects on yield and peanut growth were inconsistent. Neither varying application timing nor rate resulted in peanut yield that was different than when adhering to the label recommendations. Increasing sites of action studies concluded that broadleaf signalgrass and Amaranthus species control was optimized at four SOAs and two SOAs, respectively. Based on this study, the current recommendation of additional SOAs will not result in increased weed control.

Efforts to implement integrated pest management (IPM) strategies and improving our understanding of existing strategies are keys to achieving adequate control of tarnished plant bug, Lygus lineolaris. Insecticide applications are a part of IPM and monitoring their efficacy is critical for producers to remain profitable. Resistance to imidacloprid, thiamethoxam, and sulfoxaflor was documented, although there continues to remain variability among populations within the region. The insect growth regulator, novaluron, although only lethal to nymphs, plays an important role in management of Lygus. Sublethal impacts to adult plant bugs may be an important factor in reducing populations within the growing season. Future research to confirm the validity of using a laboratory colony as a baseline for insecticide susceptibility is needed to account for increased vigor of insects reared on artificial diet.

Flower forcing to meet holiday market can increase the value of potted flowering plants. This study was to investigate the effects of chilling and post-chilling photoperiod treatments on flowering of banana shrub and the effects of water stress, daminozide, chlormequat, and ethephon on flowering of bougainvillea. Experiments were conducted at R.R. Foil Plant Science Research Center and MSU Dorman Greenhouse at Mississippi State University (MSU), Mississippi State, MS. Results from banana shrub experiment indicated that 8-week chilling at 8 ºC was necessary for banana shrub to break bud dormancy and a tank mix of daminozide and chlormequat was able to increase the number of flower buds on banana shrub. Results from bougainvillea experiment indicated that water stress, daminozide, and chlormequat enhanced flowering. In conclusion, this study provided fundamental information to future research on flower forcing of banana shrub and bougainvillea.

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Advances in very large scale integration (VLSI) technologies impose challenges for voltage regulator modules (VRM) to deliver high-quality power to modern microprocessors. As an enabling technology, multiphase converters have become the standard practice in VRM industry. The primary objectives of this dissertation are to develop advanced topologies and innovative integrated magnetics for high-efficiency, high-power-density and fast-transient VRMs. The optimization of multiphase VRMs has also been addressed. Today's multiphase VRMs are almost universally based on the buck topology. With increased input voltage and decreased output voltage, the multiphase buck converter suffers from a very small duty cycle and cannot achieve a desirable efficiency. The multiphase tapped-inductor buck converter is one of the simplest topologies with a decent duty cycle. However, the leakage inductance of its tapped inductors causes a severe voltage spike problem. An improved topology, named the multiphase coupled-buck converter, is proposed. This innovative topology enables the use of a larger duty cycle with clamped device voltage and recovered leakage energy. Under the same transient responses, the multiphase coupled-buck converter has a significantly better efficiency than the multiphase buck converter. By integrating all the magnetic components into a single core, in which the windings are wound around the center leg and the air gaps are placed on the two outer legs, it is possible for multiphase VRMs to further improve efficiency and cut the size and cost. Unfortunately, this structure suffers from an undesirable core structure and huge leakage inductance. An improved integrated magnetic structure is proposed to overcome these limitations. All the windings are wound around the two outer legs and the air gap is placed on the center leg. The improved structure also features the flux ripple cancellation in the center leg and strongly reverse-coupled inductors. Both core loss and winding loss are reduced. The steady-state current ripples can be reduced without compromising the transient responses. The overall efficiency of the converter is improved. The input inductor can also be integrated in the improved integrated magnetic structure. Currently, selecting the appropriate number of channels for multiphase VRMs is still an empirical trial-and-error process. This dissertation proposes a methodology for determining the right number of channels for the optimal multiphase design. The problem formulation and general method for the optimization are proposed. Two examples are performed step by step to demonstrate the proposed optimization methodology. Both are focused on typical VRM 9.0 designs for the latest Pentium 4® microprocessors and their results are compared with the industry practice. / Ph. D.