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Electrospinning of nanofibrous mats and scaffolds enables generation of scaffolding that is not only highly porous, but also has a structure that essentially mimics the natural basement membrane. As a result, the method has proliferated extensively, and is commonly used for diverse applications such as water filtration or tissue engineering, the latter of which may involve the use of natural or synthetic materials. Common laboratory scale electrospinning setups can be built inexpensively with merely a syringe pump, a high voltage supply, and an aluminum foil target. These systems, however, are limited to flat target surface geometries that span several centimeters. While a scaffold can be cut or folded to conform to a bone or other biological surface, spinning directly onto a surface with significant peaks and troughs results in poor fiber uniformity. Furthermore, if an alteration of fiber properties is preferred, the high voltage setup limits user access and customization of parameters during the spinning period. Finally, control of the electric field is compromised by the proximity of grounded electrical components. As its first aim, this project develops a robotic control system to enable custom coatings of arbitrary surfaces. By augmenting the traditional electrospinning system with a three-dimensional robotic control system, electric field focusing fibers, and additional aerodynamic forces terms ‘electroblowing’, the device can be produced across targets with strong topographic anisotropy. The second aim continues to enhance these attributes with biocompatible soy based scaffolds. Craniofacial implants are often complex in geometry, and conformal bandages are particularly hard to produce in these areas. Soy based scaffolds will be produced for 3D-printed replicas of these situations. Finally, the methods developed across this aim enables the development and use of a handheld electrospinning system that combines a coaxial high velocity air flow with the high voltage spinning element to reduce effects of operator error. The final goal of the thesis is to test whether fiber control successfully reduces effects of fiber anisotropy in vitro and to use the enhanced fiber control mechanisms to produce scaffolds with significant anisotropy, depositing aligned fibers at a target point to eventually enable generation of scaffolds with programmable variable spatial alignment similar to tendon. When completed, the systems described will enable custom production of coatings or scaffolds for functionality as scaffolding on medically relevant surfaces. Specifically, this means first, that scaffolds can be used with confidence to improve fixation even of non-cylindrical implants and enhance local tissue integration, and second, that implants can be customized with areas of ‘guidance’ fibers or local drug depots to either promote regeneration and population by surrounding tissue or mimic natural anisotropic cues necessary for mechanical or biological functionality. / Bioengineering

<p dir="ltr">Hybrid metamaterials have garnered significant attention in recent years owing to their unique properties not found in natural materials. These materials are engineered by integrating two or more distinct materials at the nanoscale, forming various microstructures such as particle-in-matrix, pillar-in-matrix, and multilayers. The recent development of vertically aligned nanocomposites (VANs) offers a platform in forming pillar-in-matrix metamaterials in a self-assembled fashion. Transition metal nitrides, such as titanium nitride (TiN), are interesting materials for VAN designs due to their outstanding plasmonic properties, chemical stability, and compatibility with various functional materials. However, the current range of material selection and morphological demonstrations in two-phase nitride-based nanocomposites is limited. There is a growing need for a deeper understanding of the self-assembly growth mechanism and greater freedom in structural and property tunability of nitride-based VANs to develop the next generation of integrated photonic and electronic devices.</p><p dir="ltr">This dissertation investigates the design, growth mechanisms, and tunability of nitride-based VANs for advanced metamaterial applications. The first chapter focuses on integrating ferromagnetic CoFe₂ into a plasmonic TiN matrix to achieve anisotropic optical and magnetic properties, as well as coupling effects between the two phases. In the second chapter, a third phase, gold (Au), is introduced into TiN-CoFe₂ VANs in a core-shell configuration, demonstrating enhanced tunability in microstructure and resultant properties, such as distinct hyperbolic behavior and switchable magnetic easy axis. The third chapter extends the exploration into three-dimensional (3D) nanostructured films by combining different VAN films (e.g., TiN-CoFe₂, TaN-CoFe₂) in multilayer configurations, demonstrating highly tunable optical properties along with ferromagnetic response. This 3D nanocomposite approach highlights the potential for advanced tunability in metamaterials beyond traditional two-phase VAN designs. The fourth chapter explores the control of stoichiometry and phase composition in TiN-CuO systems. By systematically adjusting oxygen partial pressure during deposition, a gradual transition from metallic to dielectric behavior in these nanocomposite films has been observed. This investigation provides valuable insights into the comprehensive understanding of the interaction processes within hybrid nanocomposites during self-assembly. Overall, this thesis presents diverse methodologies for tuning microstructures and functionalities within nitride-based VAN systems, showing potentials for advanced applications in optics, magnetics, and beyond in metamaterial research.</p>

Advanced composites are extremely strong, rigid, and light, even when compared with advanced metals. Advanced composites are replacing high-tech metals as the material of choice for aerospace engineering. However, the processes used to manufacture advanced composites generally lose some of the properties of the materials by their process limitations. One process that keeps the theoretically awesome qualities of the composite materials in tact is filament winding. Filament wound parts are used as rocket shells, bicycle frame tubes, drive shafts, pressure vessels, etc. Filament winding is an automated process and makes reliable parts to close tolerances. If a straight tube were to be made by all the existing composites manufacturing processes, filament wound tubes would be significantly better than any other. However, filament winding is generally limited to making straight tubes. A new process based on filament winding is proposed; one that can wind complex shapes of the same high quality as conventional filament winding. This process has achieved this by winding continuous, uncut, and aligned fibers. This process is called Lotus Filament Winding.

Carbon nanotubes (CNTs) have been assessed for their use in electrochemical energy storage applications, namely Hydrogen Storage and Vanadium Redox Flow Batteries. Furthermore;fundamental electrochemical studies have been conducted on aligned arrays of carbon nanotubes, and for the first time electrochemistry on pure, defect free, single layer graphene is reported. CNTs have been assessed for their potential as an electrochemical hydrogen storage material,finding a maximum recorded capacity for a single walled nanotube sample (SWNT) that was comparable to literature gas phase adsorption values. In-situ Raman spectroelectrochemistry was used to probe structural changes of the SWNTs with applied potential: no chemical functionalisation of the tubes or intercalation of protons was observed. It was concluded, therefore, that CNTs present no unique electrochemical hydrogen storage ability, other than their role as an adsorbent for gaseous hydrogen, which was evolved electrochemically. CNTs were also assessed as a possible electrode material for the VO(2+)/VO2(+) reaction, used in the positive half cell of commercial vanadium redox flow batteries and widely reported to exhibit quasi-reversible kinetics on carbon electrodes. Initial investigations revealed apparently reversible kinetics using a SWNT, the first time such a response has been observed on Carbon, and in contradiction to published work using CNTs for this application. Analysis via a range of electrochemical techniques highlighted the difficulty in using cyclic voltammetry to assess reversibility, particularly for CNT modified electrodes. The system was subsequently found to be quasi-reversible, with the deceptively small peak separation inferred to arise from the pores of the CNT electrode, therefore thin layer cell behaviour was observed. The porous contribution was confirmed using an electrode exhibiting poor kinetics (very small, indistinct Faradaic peaks), increasing the electrode porosity (using an aligned array of CNT) had a remarkable effect, with large Faradaic peaks (low separation ˜ 0.02-0.04 V) observed for a sample that was chemically identical. This work highlights the fundamental error in a portion of CNT literature, where kinetic enhancement is quantified by voltammetric peak separation, which can be erroneous unless the inherent porosity of the electrodes is considered. In contrast to the complexity of CNTs, graphene represents an ideal electrode material, allowing for direct determination of the electrochemical response of the graphene basal plane, eliminating the contribution of edge sites. An initial investigation towards this goal is presented.

Nerve injury is a serious clinical problem that has a direct impact on the quality of life. Nerve tissue engineering (NTE) is one of the most promising methods in human health care to restore the function of damaged neural tissues. The current state of the art involves the construction of a tissue engineered, nano or micropatterned 3-D nerve tube that has fibers or channels in the inside. The scope of this study is to construct a 3-D, biodegradable nerve tube which consists of an aligned, electrospun mat seeded with stem cells that is wrapped in a porous micropatterned film which contains support cells. In two separate approaches human mesenchymal stem cells (MSCs) and mouse neural stem cells (NSCs) were used. In the design with the MSCs, the micropatterned exterior part of the nerve tube contained undifferentiated MSCs as support cells and this was wrapped around the fibers seeded with MSCs which were induced to neural differentiation. In the other case, NSCs differentiated into astrocytes were used as support cells seeded on the micropatterned film and the mat was loaded with undifferentiated NSCs. Differentiation into neural cells and astrocytes were shown with immunocytochemistry and RT-PCR. The neuron-like MSCs and NSCs were shown to express neural marker &amp / #946 / -Tubulin III whereas astrocytes expressed glial fibrillary acidic protein (GFAP), an astrocyte marker. RT-PCR showed that early neural markers, nestin and Nurr 1, were expressed at passage 4 by undifferentiated MSCs and by MSCs induced to neural differentiation, while these markers were not expressed in undifferentiated MSCs at passages 2 and 3. The cells aligned along the axis of the micropattern of the film and along the axis of the fiber on the fibrous mat. This behavior was also maintained after construct formation. MTS and confocal microscopy revealed that the cells were viable and homogeneously distributed over the two parts of the scaffold. This indicates that the construct has a potential to be tested in vivo for nerve tissue engineering purposes.

In light of the continual debate among researchers regarding new teachers’ concerns about classroom management and the need to insure that instruction results in positive student learning the focus of this qualitative case study has been to examine how five second and third year teachers planned for and thought about the management of student engagement during instruction. The main purpose of this study was to examine the professional thinking of five second and third year teachers while planning for a lesson in comparison to their actions during the lesson and later how they reflected on that plan. In addition, the teachers’ beliefs about how they learned to integrate management with instruction during planning were examined. The results of this study indicate these five teachers did intentionally think about and plan for the integration of management with instruction during their lessons. District aligned curricula were used in each of these teachers’ districts which caused them to alter the traditional planning model so they could plan for the integration of management with instruction in their lessons. In addition these teachers believed they learned to address management with instruction as a result of their first year(s) of teaching. / text

To a rapidly increasing degree, traditional organizational structures evolve in large parts of the world towards online business using modern Information and Communication Technology (ICT) capabilities. For efficient applications of inter-organizational information systems, the alignment between business and ICT is a key factor. In this context, business analysis using business modelling can be regarded as a first step in designing economically sustainable e-business solutions. This thesis examines how business modeling can be used to improve e-business design. We examine how business stakeholder intentions and different objectives of business collaborations can be used to obtain an explorative business model that can be used as a basis for designing e-business solutions. The thesis proposes a set of artifacts for business modeling and e-service design. In regard to business modeling, we propose methods that consider internal aspects such as strategic intentions of actors and external aspects such as business collaborations among them. Considering stakeholder intentions, we introduce a method to design business models based on goal models. A set of templates for designing goal models and a set of transformation rules to obtain business models based on goal models are proposed. To further improve business models considering business collaborations, we suggest a classification of business transactions that considers underlying business objectives of business collaborations. Utilizing the suggested business transactions, we then propose a method to improve business modeling. Finally, we propose a method for designing e-services using business models. The methods suggested support business modelers as well as process and services designers in executing their tasks effectively. The methods have been assessed through applications in two cases.

Solid oxide fuel cells (SOFCs) are very attractive as energy generation devices because they are clean, reliable, and almost entirely pollution-free. SOFCs have flexible fuel selections compared with other fuel cell technologies. The main disadvantage of SOFCs is their high operating temperature (~1000ºC for conventional SOFCs) which leads to cell cracking and formation of non-conducting compounds at electrolyte/electrode interfaces. Therefore, intermediate temperature SOFCs (ITSOFCs) in the range of 500-700 ºC has attracted extensive research interests. To achieve high cell performance at reduced temperatures, it requires high-catalytic activity, high ionic conductivity, and comparable thermal expansion coefficient (TEC) of the cell components. To address the above issues, the research focuses on two main approaches (i.e., the interlayer approach and the electrolyte approach) in order to improve the overall cell performance. First, the design of a thin layer of a vertically-aligned nanocomposite (VAN) structure as an interlayer between the electrolyte and cathode is demonstrated. The development of the VAN structures consisted of the cathode material as a perovskite or ordered double perovskite structure, La0.5Sr0.5CoO3 (LSCO) or PrBaCo2O5 delta (PBCO), and the electrolyte material as a fluorite structure, Ce0.9Gd0.1O1.95 (CGO or GDC), were achieved for thin film solid oxide fuel cell (TFSOFCs). The VAN structure significantly improves the overall performance of the TFSOFC by increasing the interfacial area between the electrolyte and cathode and also acts as a transition layer that improves adhesion and relieves both thermal stress and lattice strain. Second, microstructural and electrical properties of Gd-doped CeO2 (GDC, Ce0.9Gd0.1O1.95) thin films electrolyte are studied for intermediate temperature solid oxide fuel cells (SOFCs). The GDC thin film electrolytes with different grain sizes and grain morphologies were prepared by varying the deposition parameters such as substrate temperature, oxygen partial pressure, target repetition rate, and laser ablation energy. The electrical property of the GDC thin film is strongly affected by the grain size. Third, bilayer electrolytes composed of a gadolinium-doped CeO2 (GDC) layer (~6 micrometer thickness) and an yttria-stabilized ZrO2 (YSZ) layer with various thicknesses (~330 nm, ~440 nm, and ~1 micrometer) are achieved by a pulsed laser deposition (PLD) technique for thin film solid oxide fuel cells (TFSOFCs). One effective approach is to incorporate YSZ thin film as a blocking layer in between the GDC and anode for preventing chemical reduction of GDC and electrical current leakage. This bilayer approach effectively improves the GDC's chemical/ mechanical stability and reduces the OCV loss under reducing conditions. The results suggest that the YSZ thin film serves as a blocking layer for preventing electrical current leakage in the GDC layer and also provides chemical, mechanical, and structural integrity in the cell, which leads to the overall enhanced performance.

Thesis (MA)--Stellenbosch University, 2002. / ENGLISH ABSTRACT: The purpose of this study is to determine how the role and identity of the Nonaligned Movement (NAM) changed during and after the Cold War. The demise of the Movement in the post-Cold War era, predicted by some scholars, is discussed. This study examines whether the Movement merely offered an alternative grouping during the Cold War. The issue that becomes evident with respect to the Cold War is to show the terror it brought about and how the Third World became the battleground of the Superpowers. The question as to what extent the role played by the Movement defused the Cold War is investigated. It is shown that the Movement sent emissaries to Washington and Moscow to resolve the German Crisis in 1961 and to reduce the arms race. A historical overview of the Movement is offered, which determines the role of Afro- Asianism in the birth of the Nonaligned Movement. It is explained that the 1955 Bandung conference gathered leaders from independent African and Asian states - with different foreign policies - which created energies that in the following years greatly affected Third World politics and the shaping of nonalignment. This study traces also the role of different gatherings of the Movement up to the Durban Summit of 1998. At issue are also participating countries in the 1961 Belgrade Summit, which are described, as well as the growth of the Movement's membership. Different goals of the Movement are examined. Some, like nuclear disarmament, the right to self-determination, peaceful coexistence, and the right for the Palestinians to a homeland, were adopted during the Cold War and still remain valid. Others, like protection of the environment, and the struggle for human rights, were implemented during the post-Cold War era. The détente allowed the Movement to launch a New International Economic Order. An attempt is made to show the failure and success of the Movement in this respect. / AFRIKAANSE OPSOMMING: Die doel van hierdie studie is om te bepaal hoe die rol en identiteit van die Onverbonde Beweging (NAM) tydens en na die Koue Oorlog verander het. Die ondergang van die Beweging in die na-Koue Oorlogse era soos deur sommige kenners voorspel is, word ook ondersoek. Die studie het probeer vasstelof die Beweging 'n alternatiewe groepering tydens die Koue Oorlog teweeg gebring het. Die kwessie met betrekking tot respect tot die Koue Oorlog bewys dat terreur meegebring word en hoe die Derde Wêreld die slagveld van die Supermoondhede gemaak het. Daar word ook gepoog om vas te stel tot watter mate die Beweging 'n rol gespeel het in die ontlonting van die Koue Oorlog. In die verband word onder andere verwys na die Beweging se pogings om die Duitse Krisis (1961) te ontlont en die wapenwedloop te beëindig deur die stuur van afgevaardigdes na Washington en Moskou. In 'n historiese oorsig van die Beweging word die rol wat 'n Afro-Asiatiese gevoel/gees in die stigting van die Onverbonde Beweging gespeel het, ondersoek. Die studie toon aan hoe die Bandung Konferensie van 1955 leiers van onafhanklike state van Afrika en Asië, wat uiteenlopende buitelandse beleidsrigtings gehad het, bymekaar gebring het. Hierdie uiteenlopendheid het 'n dinamika geskep wat Derde Wêreldse politiek en die aard van onverbondenheid wesenlik beinvloed het in die jare na die Konferensie. Verskeie byeenkomste van die Onverbonde Beweging tot en met die Durbanse spitsberaad (1998) word ontleed. Die samestelling en verloop van die spitsberaad in Belgrado in 1961 en die groei in die lidmaatskap van die Beweging kom onder andere onder die loep. Verskeie van die Beweging se doelwitte wat tydens die Koue Oorlog beslag gekry het en steeds geldig is, word onder die soeklig geplaas. Kernkrag ontwapening, die reg op selfbeskikking, vreedsame naasbestaan en die Palestyne se reg op 'n eie staat/tuisland is voorbeelde in die verband. Ander doelwitte van die beweging wat veral in die na-Koue Oorlogse era geimplementeer is, soos die bewaring en beskerming van die omgewing en die stryd om menseregte, word ook ondersoek. Die loodsing van 'n Nuwe Internasionale Ekonomiese Orde deur die Beweging wat deur die détente van die na-Koue Oorlogse era moontlik gemaak is, word ook bespreek en die sukses en mislukking daarvan geëvalueer.