Over the last few years, flexible electronic systems have gained increased attention from researchers around the world because of their potential to create new applications such as flexible displays, flexible energy harvesters, artificial skin, and health monitoring systems that cannot be integrated with conventional wafer based complementary metal oxide semiconductor processes. Most of the current efforts to create flexible high performance devices are based on the use of organic semiconductors. However, inherent material's limitations make them unsuitable for big data processing and high speed communications. The objective of my doctoral dissertation is to develop integration processes that allow the transformation of rigid high performance electronics into flexible ones while maintaining their performance and cost. In this work, two different techniques to transform inorganic complementary metal-oxide-semiconductor electronics into flexible ones have been developed using industry compatible processes. Furthermore, these techniques were used to realize flexible discrete devices and circuits which include metal-oxide-semiconductor field-effect-transistors, the first demonstration of flexible Fin-field-effect-transistors, and metal-oxide-semiconductors-based circuits. Finally, this thesis presents a new technique to package, integrate, and interconnect flexible high performance electronics using low cost additive manufacturing techniques such as 3D printing and inkjet printing. This thesis contains in depth studies on electrical, mechanical, and thermal properties of the fabricated devices.

ABSTRACT Carton Clamp Test Methodologies and the Effects on Load Containment and Retention Tyler Don Blumer A carton clamp is an alternative device for moving packages and material. Instead of using iron tines like that of a conventional forklift, a carton clamp uses two large aluminum platens to slightly compress and secure the load for handling. This is advantageous as it allows operators to move layers of a unitized load individually, and eliminates the need for a pallet when handling full unitized loads. When using a carton clamp attachment, it is often difficult for operators to accurately gauge the amount of force being applied to the load. The required clamping force changes depending on the size, shape, and weight of the load. This creates the potential for under-clamping (slippage) and over-clamping (compressive damage). Seeing a market need for a reliable means of testing, two organizations set out to develop a testing protocol. A rift formed between schools of thought regarding the correct testing procedure. ISTA provides a sterile, calculated, and stationary simulation of carton clamp handling in its ISTA 6-SAMS test protocol. ASTM offers a more holistic, dynamic, observational approach in its mobile ASTM 6055 standard protocol. One school of thought is suggested to imply that a package should be developed to be handled by the carton clamp (ASTM). The other school of thought is that the carton clamp attachment should be properly adjusted to the package specimen (ISTA). Previous studies have been performed citing the ISTA standard and using a specialized carton clamping device vibration device that is calibrated for laboratory research. Arguably, this method, though repeatable in nature, does not accurately simulate carton clamp handling found in industry. Likewise, the equipment investment is cost prohibitive for those in industry wishing to duplicate such a study. ASTM uses a carton clamp truck as used in industry, but does not specify any specific parameters making repeatability between laboratories and practitioners ambiguous. This study examined whether or not a common ground can be reached; implementing a carton clamp lift truck as found in industry allowing for mobile (hazard course) testing. A modified version of ISTA 3B will be paired off against ASTM 6055 for evaluating both column and cross stack pallet patterns with a variety of treatments. This study attempted to determine if carton clamps as found in industry are capable and repeatable enough to provide consistent data. Similarly, this study examined the test methodologies effect on load containment via stretch film force, load retention via unitized load slippage, and the effects of ride height and driver interaction. The study sought to understand if these effects are uniform across the unitized load, or if particular layers of the load more affected than others.

Rapid detection of live pathogens is of paramount importance to ensure food safety. At present, nucleic acid-based polymerase chain reaction and antibody-based lateral flow assays are the primary methods of choice for rapid detection, but these are prone to interference from inhibitors, and resident microbes. Moreover, the positive results may neither assure virulence potential nor viability of the analyte. In contrast, the mammalian cell-based assay detects pathogen interaction with the host cells and is responsive to only live pathogens, but the short shelf-life of the mammalian cells is the major impediment for its widespread application. An innovative approach to prolong the shelf-life of mammalian cells by using formalin was undertaken. Formalin (4% formaldehyde)-fixed human ileocecal adenocarcinoma cell line, HCT-8 on 24-well tissue culture plates was used for the capture of viable pathogens while an antibody was used for specific detection. The specificity of the <u>M</u>ammalian <u>C</u>ell-based <u>I</u>mmuno<u>A</u>ssay (MaCIA) was validated with <i>Salmonella enterica</i> serovar Enteritidis and Typhimurium as model pathogens and further confirmed against a panel of 15 S. Enteritidis strains, 8 S. Typhimurium,11 other <i>Salmonella</i> serovars, and 14 non-<i>Salmonella</i> spp. The total detection time (sample-to-result) of MaCIA with artificially inoculated ground chicken, eggs, milk, and cake mix at 1-10 CFU/25 g was 16-21 h using a traditional enrichment set up but the detection time was shortened to 10-12 h using direct on-cell (MaCIA) enrichment. Formalin-fixed stable cell monolayers in MaCIA provide longer shelf-life (at least 14 weeks) for possible point-of-need deployment and multi-sample testing on a single plate.

Marketers increasingly face challenges in trying to understand the decision-making processes and behaviours of those consumers located at the Bottom of the Pyramid (BOP). It has been proven that 73% of fast-moving consumer goods (FMCG) purchases are made at the point-of sale, and product packaging has been found to play a strategic role in seven of the ten in-store purchase decision criteria. Packaging is, therefore, an important basis through which companies can differentiate products from the plethora of competing brands. On average, big retailers carry 50 000 items and the typical shopper passes 300 items per minute. The packaging must, therefore, perform many of the sales tasks, making an overall favourable brand impression and experience. The research has attempted to understand the constructs of packaging and brand experience as purchasing decision criteria for FMCG products. The researcher administered 250 surveys with low-income consumers in the Star Hyper supermarket in the mining town of Carltonville. The findings demonstrated how low-income consumers have an appreciation of all product packaging as they often re-use it once the product is consumed. Furthermore, lower income consumers enjoy a greater brand experience with 'premium' product brands when compared to their brand experience levels with what they perceive to be 'cheaper' brand products. Even though a statistical weak relationship between product packaging and brand experience was found, the qualitative findings support the notion of a strong relationship as lower income consumers gain more value/greater brand experience not just out of consuming 'premium' brand products, but also from the use of the packaging for other needs afterwards. Copyright / Dissertation (MBA)--University of Pretoria, 2010. / Gordon Institute of Business Science (GIBS) / unrestricted

Hemicelluloses (HC) are the second most abundant plant polysaccharides after cellulose, constituting 25-30% of plant materials. In spite of their abundance, HC are not effectively utilized. Recently, considerable interest has been directed to HC-based biomaterials because of their high oxygen barrier properties, which has potential in food packaging applications. In this study, HC were extracted from sugarcane bagasse and southern yellow pine using a hydrothermal technique which utilizes hot compressed water without catalyst. The parameters affecting the yield of extracted HC such as temperature, time and pressure, were tested and optimized. Eighty four percent of xylose was extracted from sugarcane bagasse at the optimum condition, 180 °C 30 min and 1 MPa pressure. In the case of southern yellow pine, 79% of the mannose was extracted at 190 °C for 10 min and 2 MPa pressure. Concentration and isolation of HC from bagasse and southern yellow pine HC extract were performed by membrane filtration and freeze drying systems. Isolated HC were characterized by FT-IR and 13C NMR techniques and used as a starting material for film preparation. Films were prepared in 0/100, 50/50, 60/40, 70/30 and 80/20% ratios of HC and sodium carboxymethylcellulose (CMC). Thirty five percent of sorbitol (w/w of HC and CMC weight) was also added as a plasticizer. Films were evaluated by measuring water absorption, water vapor permeability (WVP), tensile property and oxygen barrier capability. At 55% relative humidity (RH) and 25 °C the water absorption of both sugarcane bagasse and southern yellow pine HC-based films tended to increase as HC content increased. The lowest WVP of sugarcane bagasse (3.84e-12 g/Pa h m) and southern yellow pine HC films (2.18e-12 g/Pa h m) were determined in 60/40 HC/CMC films. Tensile test results showed that as HC content increases the Young’s modulus decreases, deflection at maximum load and percentage of strain at break increase. It implies that the film properties are changing from stiff to elastic. The oxygen permeability for 60/40 bagasse HC/CMC film was 0.005265 cc μm / (m2 day kPa) and for 70/30 pine HC/CMC film was 0.007570 cc μm /(m2 day kPa).

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Optical beamforming networks (OBFNs) are a strong contender for phased array operation, especially using microwave photonics (MWP), with advantages in size, weight, power efficiency and cost. Applications for such systems range from satellite to cellphone communication. The use of OBFNs require multiple components to up-convert, down-convert and process radio frequency (RF) signals in the optical domain. In this thesis, these components and a photonic packaging solution were designed and tested. For the OBFN itself, the modulation for up-conversion was performed with a micro-ring modulator, which was able to perform 1.11V forward bias modulation at 500MHz with a modulation depth of 21 dB. A true time delay optical ring resonator (ORR) was designed and characterized, yielding 784 ps delay at 3.33V heater bias, tunable to any value below this. An accessible, low-cost photonic packaging approach was developed, which achieved an optical coupling loss of 2.8 dB per facet. In conjunction with the photonic packaging was an electromagnetic interference (EMI) enclosure, which was able to block unwanted external RF signals. / Thesis / Master of Applied Science (MASc)

This thesis investigates techniques for prototyping and evaluation of medium voltage (MV) power module packages. Specific focus will be given to the utilization of silver sintering as a bonding method for high temperature, high density power modules. Nano-silver paste and preform will be examined in detail as enabling technologies for a new generation of power electronics. To accomplish this task, analysis and characterization of the metal-ceramic substrate and its structure is performed. First, finite element models are created to evaluate the fatigue behavior of the large area bonds in the substrate structure. Prototypes of these multi-layer substrates have also been fabricated and will be subjected to thermal cycling tests for experimental verification of the efficacy of their sintered silver bonds. Stacked direct-bonded aluminum (DBA) substrates have been found to withstand up to 1000 thermal cycles of –40 °C to 200 °C when attached with low pressure-assisted silver sintering. The thermal performance of 10 kV SiC power module utilizing multi-layer DBA substrates bonded with a large-area, low pressure-assisted sintered silver bond will also be examined to ensure the sintered bond is viable for the harsh operating conditions of MV modules. A junction-to-case thermal resistance of 0.142 °C/W is measured on a module prototype utilizing stacked DBA substrates. Finally, analysis of a double-sided cooling scheme enabled by large area sintering is simulated and prototyped to demonstrate a 6.5 kV package for a MV power device. Residual stress failures induced by a highly rigid structure have been examined and mitigated through implementation of a 5 MPa pressure-assisted, double-sided silver sintering approach. / Master of Science / Power modules are the building blocks of the electrical grid of the future. As society transitions to renewable energy to fight the crisis presented by climate change, the structure of the energy grid will have to change to accommodate the increase in solar, wind, geothermal, and other renewable sources of energy generation. A clean energy grid structure will contain ubiquitous opportunities to use power modules for medium-voltage (MV) applications, like managing the flow of electricity from solar panels and wind turbines to neighborhoods and office buildings. However, these MV power modules will need to be resilient to extreme temperature and electrical stresses inherent to these applications. Current technology must be improved in both performance and reliability to match the needs of this future grid. This thesis investigates, through both experiment and computer simulation, techniques for improving the reliability of MV power modules without sacrificing thermal or electrical performance. Techniques presented in this work have the potential to transform power modules, so they may operate at higher temperatures and efficiencies for a longer lifetime than the current state-of-the-art.