Based on the form-invariant of Maxwell’s equations under coordinate transformations, we extend the theoryof transformation optics to transformation magneto-statics, which can design magnets through coordinatetransformations. Some novel DC magnetic field illusions created by magnets (e.g. rescaling magnets,cancelling magnets and overlapping magnets) are designed and verified by numerical simulations. Ourresearch will open a new door to designing magnets and controlling DC magnetic fields. / <p>QC 20141105</p>

In this paper we consider optimum design of experiments for correlated observations. We approximate the error component of the process by an eigenvector expansion of the corresponding covariance function. Furthermore we study the limit behavior of an additional white noise as a regularization tool. The approach is illustrated by some typical examples. (authors' abstract) / Series: Research Report Series / Department of Statistics and Mathematics

This study explored the effects of cognitive style and expected evaluation on creativity. Past research has shown that an expectation of evaluation can have a negative impact on creativity, and those individuals classified as field-independent rather than field-dependent are more likely to have higher creativity scores. An interaction between expected evaluation and cognitive style was hypothesized. Participants created a collage to measure creativity, either with or without an expectation of evaluation, and then cognitive style was measured. The hypothesis was partially supported. The more field-independent an individual, the higher the creativity score. Those in the evaluation condition scored higher in creativity than those in the non-evaluation condition, but this effect disappeared when controlling for time and previous art experience. The effect of expected evaluation is discussed in terms of the experimental situation and the conceptualization of motivation. Further investigations of cognitive style and motivational conditions are suggested. / Department of Educational Psychology

The ligands 2-cyanocyclopentyldiphenylphosphine and 2-cyanocyclohesyldiphenylphosphine were synthesized from 1-cyanocyclopentene and 1cyanocyclohexene by addition reactions using diphenylphosphine and aqueous base as the catalyst. These ligands reacted with Pt(II) and Pd(II) salts to yield complexes of the stoichiometry MX2L2 (X = C1, Br). In these complexes the ligands were found to function as monodentate phosphines. Infrared spectroscopic evidence suggested that the platinum complex was of cis and the palladium complexes were of trans geometries.The reactions of the ligands 2-cyanocyclopentyldiphenylphosphine and 2-cyanocyclohexyldiphenylphosphine or the ligand 2-cyanoethyldiphenylphosphine with the complexes dimethyyl(cyclooctadiene)platinun(II) or methyl) (chloro) (cyclooctadiene) platinum(II) resulted in complexes of the stoichiometries Pt(CH3)2L2 and Pt(CH3)(C1)L2. In these complexes the ligands also functioned as monodentate phosphines. hmr and far infrared spectroscopic evidence suggested that the dimethylplatinuin(II) complexes were cis and the (methyl)(chloro)platinum(II) complexes were trans.A complex of the stoichiometry Pd2Cl4(Ph2PC6H10CN)2 was isolated from the reaction of a 1:1 mole ratio of PdC12 with Ph2PC6H10CN. Far infrared and Raman spectroscopic evidence 'suggested that the complex was a chlorine bridged dieter with the ligands at symmetrical positions. The nitrile groups in this complex reacted rapidly with alcohols to yield monomeric imino ether complexes.The Pt(CH3)(C1)L2 complexes reacted with AgPF6 to yield cationic salts of the stoichiometry [Pt(CH3)L2]n+n with one ligand in each [Pt(CH3)L2]+ unit presumably serving as a bridging ligand and the other as a monodentate phosphine. The coordinated nitrite groups in these complexes reacted slowly with methanol to yield amino ether complexes.

Simultaneous Localization and Mapping (SLAM) is a recursive probabilistic inferencing process used for robot navigation when Global Positioning Systems (GPS) are unavailable. SLAM operates by building a map of the robot environment, while concurrently localizing the robot within this map. The ultimate goal of SLAM is to operate anywhere using the environment's natural features as landmarks. Such a goal is difficult to achieve for several reasons. Firstly, different environments contain different types of natural features, each exhibiting large variance in its shape and appearance. Secondly, objects look differently from different viewpoints and it is therefore difficult to always recognize them. Thirdly, in most outdoor environments it is not possible to predict the motion of a vehicle using wheel encoders because of errors caused by slippage. Finally, the design of a SLAM system to operate in a large-scale outdoor setting is in itself a challenge. <br /><br /> The above issues are addressed as follows. Firstly, a camera is used to recognize the environmental context (e. g. , indoor office, outdoor park) by analyzing the holistic spectral content of images of the robot's surroundings. A type of feature (e. g. , trees for a park) is then chosen for SLAM that is likely observable in the recognized setting. A novel tree detection system is introduced, which is based on perceptually organizing the content of images into quasi-vertical structures and marking those structures that intersect ground level as tree trunks. Secondly, a new tree recognition system is proposed, which is based on extracting Scale Invariant Feature Transform (SIFT) features on each tree trunk region and matching trees in feature space. Thirdly, dead-reckoning is performed via an Inertial Navigation System (INS), bounded by non-holonomic constraints. INS are insensitive to slippage and varying ground conditions. Finally, the developed Computer Vision and Inertial systems are integrated within the framework of an Extended Kalman Filter into a working Vision-INS SLAM system, named VisSLAM. <br /><br /> VisSLAM is tested on data collected during a real test run in an outdoor unstructured environment. Three test scenarios are proposed, ranging from semi-automatic detection, recognition, and initialization to a fully automated SLAM system. The first two scenarios are used to verify the presented inertial and Computer Vision algorithms in the context of localization, where results indicate accurate vehicle pose estimation for the majority of its journey. The final scenario evaluates the application of the proposed systems for SLAM, where results indicate successful operation for a long portion of the vehicle journey. Although the scope of this thesis is to operate in an outdoor park setting using tree trunks as landmarks, the developed techniques lend themselves to other environments using different natural objects as landmarks.

The microwave near-field detection technique is of interest to many researchers for characterizing materials because of its high sensitivity. It is based on sensing buried objects by producing an evanescent field.The advantage of evanescent fields is their capability to interrogate electrically small objects. In the past, near-field probes have been designed to sense magnetic materials. For dielectric materials, a near-field probe that senses the permittivity of the materials is important. This work presents a novel design of a near-field probe that generates a dominant electric eld. The probe is an electrically small dipole measuring approximately 0.07?? in length operating at 216.3 MHz. The antenna is matched to a 50??? system using two chip inductors distributed symmetrically on the dipole. The numerical and measurement results show that the proposed design is highly sensitive and capable of sensing subsurface object. The proposed design is compact, lightweight and applicable for microwave applications.

Thesis (M.A. (Maatskaplike Werk)--North-West University, Potchefstroom Campus, 2008.

In this thesis we study classes of static spherically symmetric solutions to the Einstein and Einstein–Maxwell equations that may be used to model the interior of compact stars. We also study the spherical accretion of fluids on to bodies in both general relativity and the Newtonian theory of gravity. The condition for pressure isotropy is obtained upon specifying one of the gravitational potentials and the electric field intensity. A series solution was found after specifying a cubic form for the potential. The pressure and energy density appear to be non–singular and continuous inside the star. This solution admits an explicit equation of state that, in regions close to the stellar centre, may be approximated by a polytrope. Another class of exact solutions to the Einstein–Maxwell solutions was found with charge. These solutions are in the form of hypergeometric functions with two free parameters. For particular parameter values we recovered two previously known exact solutions that are reasonable models for the interior of compact stars. We demonstrated two new solutions for other choices of the parameters. One of these has well behaved pressure, energy density and electric field intensity variables within the star. The other was rejected as unphysical on the grounds that it has a negative energy density. This violates the energy conditions. We obtained the mass accretion rate and critical radius of a polytrope accreting onto a D– dimensional Schwarzschild black hole. The accretion rate, ˙M , is an explicit function of the black hole mass, M, as well as the gas boundary conditions and the dimensionality, D, of the spacetime. We also found the asymptotic compression ratios and temperature profiles below the accretion radius and at the event horizon. This generalises the Newtonian expressions of Giddings and Mangano (2008) which examined the accretion of TeV black holes. We obtained the critical radius and accretion rates of a generalised Chaplygin gas accreting on to body under a Newtonian potential. The accretion rate is about 2 - 4 times greater than that for neutral hydrogen. The Rankine–Hugoniot relations for shocked GCG flow were also found. We found general expressions for the pressure and density compression ratios. Some post shock states imply negative volumes. We suspect that these may be thermodynamically forbidden. / Thesis (Ph.D.)-University of KwaZulu-Natal, Westville, 2012.

Six field pea (Pisum sativum) varieties from five different growing locations in Saskatchewan in the 2006 and 2007 growing years were analyzed to determine the effect of genotype, environment and year on the total dietary fibre, insoluble dietary fibre, soluble dietary fibre, total phenolic content, simple phenolic content and antioxidant activities. Samples were analyzed for dietary fibre using the enzymatic-gravimetric method of fibre analysis in accordance to the AACC method 32-05. Growing location had a very significant effect (p<0.0001) on the IDF, SDF and TDF content. Genotype had a strong effect (p<0.0001) on both IDF and TDF while having no significant effect (p=0.4556) on SDF content. Crop year also displayed a significant effect on SDF and TDF (p<0.0001) while having a smaller effect on IDF content (p=0.0139). Green varieties yielded significantly higher IDF (p=0.0041) and TDF (p=0.0028) than yellow varieties. Significant genotype x location (0.0155) and location x year (p=0.0002) interaction terms were also observed for TDF. The total phenolic contents were assessed using the Folin-Ciocalteu method of total phenolic content (TPC) analysis, while the contents of 10 individual simple phenolic acids were assessed using reversed-phase UPLC. A significant genotype, environment, and genotype by environment (G x E) interaction effect on the TPC was observed. The seed coat colour and growing season did not show a significant effect on the TPC. The UPLC analysis showed that ferulic acid comprised the majority of the phenolic content of the field pea samples. There was also a genotype, seed coat colour, location, growing season and G x E effect on the total simple phenolic acid content. As well, a modified microplate method for antioxidant activity using the free radical DPPH was assessed against the conventional cuvette method based system. Both methods showed that genotype (p<0.05) and location (p<0.05) had a significant effect on antioxidant activity. A larger, significant effect was seen in the genotype by environment (G x E) interaction (p<0.0001) in the 2007 and 2008 growing years. Growing year did not have a significant on antioxidant activity. Although there was some variation in the resulting AOA values between the two methods, these differences were found not to be statistically significant by means of a folded F-Test (p < 0.05), and the AOA between the two methods was highly correlated (R² = 0.8866). This indicates that a microplate may be used in place of cuvettes to determine AOA using the DPPH free radical to increase testing speed while reducing the amount of sample and reagent used in testing. The research performed on the influence of genotype and environment could potentially allow plant breeders, food scientists and nutraceutical manufacturers to manipulate field pea genotypes and growing conditions to attain an ideal nutritional profile for use in functional foods and nutraceuticals.

This thesis will focus on spherical near-field antenna measurements and the methods developed or modified for the work of this thesis to estimate the uncertainty in a particular far-field radiation pattern. We will discuss the need for error assessment in spherical near-field antenna measurements. A procedure will be proposed that, in an automated fashion, can be used to determine the overall uncertainty in the measured far-field radiation pattern of a particular antenna. This overall uncertainty will be the result of a combination of several known sources of error common to SNF measurements. This procedure will consist of several standard SNF measurements, some newly developed tests, and several stages of post-processing of the measured data. The automated procedure will be tested on four antennas of various operating frequencies and directivities to verify its functionality. Finally, total uncertainty data will be presented to the reader in several formats.