<p>Zein is a major storage protein of corn, with unique amphiphilic film forming properties. It is insoluble in water, but soluble in 70% ethanol and acetic acid, and has been declared ‘generally recognized as safe’ (GRAS) by the FDA. Due to new advances in food nanotechnology, zein is being investigated for various applications such as biodegradable packaging, oral delivery of proteins and peptides, scaffold for tissue engineering, as well as biodegradable sensor platforms. The time consuming and highly complicated methods for toxin and allergen analysis in the food industry necessitates the need for a rapid, selective, compact and easy-to-use method of detection for analytes. In the scope of this dissertation, we investigated the feasibility of functional zein nanocomposite films and formation of a zein nanocomposite sensor assembly for rapid and highly selective electrochemical measurements of food toxins and allergens. Fabrication of a zein based electrochemical amperometric sensor assembly was studied, first through the comparison of various zein film characteristics changes with the application of Laponite®, graphene oxide and carbon nanotube nanoparticles, followed by a proof-of-concept study by detecting the gluten allergen protein gliadin. </p> <p>To mechanistically study the functional zein nanocomposite films, Laponite®, a silica nanoparticle, was added in the presence of 70% ethanol solvent and oleic acid plasticizer. The films were studied using various characterization techniques like transmission electron microscopy (TEM), Fourier transform infrared spectroscopy (FTIR), atomic force microscopy (AFM), thermogravimetric analysis (TGA), differential scanning calorimetry (DSC), water contact angle measurements etc. Through Si-N bond formation between Laponite® and zein, fabricated zein nanocomposite films showed increase in surface hydrophobicity, water vapor barrier properties, tensile strength and Young’s modulus. Graphene oxide (GO), a carbon nanoparticle, was also incorporated into zein through the solvent casting process. Uniform dispersion of GO nanoparticles within zein matrix were confirmed up to 1% GO loading, and covalent and hydrogen bonding mechanisms were proposed. Similar to zein-Laponite® (Z-LAP) nanocomposites, zein-GO (Z-GO) showed increase in hydrophobic tendencies, rougher surface and a 300% improvement in Young’s modulus and 180% improvement in tensile strength at only 3% GO loading. Both nanoparticles increased tensile strength, thermal stability and water vapor barrier property of the films, indicating a potential for food packaging as an alternative application for the nanocomposite films.</p> Finally, the research focused on the fabrication of an electrochemical amperometric sensor, capable of detecting the protein gliadin, which is responsible for the allergic reaction with people having celiac disease. Novel biodegradable coatings made from zein nanocomposites: zein-graphene oxide, zein-Laponite® and zein-multiwalled carbon nanotubes (Z-CNT) using drop casting technique were tested for fabricating the electrochemical sensors using cyclic voltammetry (CV), electrochemical impedance spectroscopy (EIS) and square wave voltammetry (SWV) techniques. As Z-CNT produced the strongest signals compared to other nanomaterials, the active tip of the electrochemical sensor was functionalized through a sequence of layer by layer deposition of Z-CNT nanocomposite, antibody and target analyte. Here, Z-CNT acts as a natural linker molecule with large number of functional groups, that causes immobilization of capture antibody and target, to ensure high sensor performance. Both CV curves and SWV curves indicated successful sequential immobilization of gliadin antibody onto the Z-CNT coated electrode. The Z-CNT biosensor was successfully able to give CV signals for gliadin toxins for as low as 0.5 ppm and was highly specific for gliadin in the presence of other interfering molecules, and remained stable over a 30-day period. The low-cost, thin, conductive zein films offered a promising alternative for protein immobilization platforms used in sensors and can be extended to other matrices in biosensors as well as other functional film applications

Considering the increasing competition between brands and products, packaging has become an important framing tool to influence customers' purchasing decisions. However, given the growing environmental concerns, zero packaging has emerged as a new practice to face the challenges of preventing and encouraging the use of packaging. With the introduction of zero packaging, marketers have been forced to reframe the practice of packaging, as artifacts used to create identification and familiarity to form a state of resonance have been removed. To extend the research of resonance within the marketing communication science, the study employed a qualitative approach to explore how food retailers are utilizing the framing concept of resonance as a means to revamp the traditional packaging into zero packaging. To reframe the practice of packaging, the study embraces the concept of cognitive and emotional resonance. The findings impose that food retailers need to create personal alignments with product artifacts, environmental values and containers. By reviewing the contextual marketing communication field, zero packaging, a third resonance was utilized to understand how the food retailers adequately attract, change and retain customers. Subsequently, affirmation was discovered as the key mechanism to achieve motivational resonance, by interfering with customers’ intrinsic and personalized values/desires.

The trend of electrification in transportation applications has led to the fast development of high-power-density power electronics converters. High-switching-frequency and high-temperature operations are the two key factors towards this target. Both requirements, however, are challenging the fundamental limit of silicon (Si) based devices. The emerging wide-bandgap, silicon carbide (SiC) power devices have become the promising solution to meet these requirements. With these advanced devices, the technology barrier has now moved to the compatible integration technology that can make the best of device capabilities in high-power-density converters. Many challenges are present, and some of the most important issues are explored in this dissertation. First of all, the high-temperature performances of the commercial SiC MOSFET are evaluated extensively up to 200 degree C. The static and switching characterizations show that the device has superior electrical performances under elevated temperatures. Meanwhile, the gate oxide stability of the device - a known issue to SiC MOSFETs in general - is also evaluated through both high-temperature gate biasing and gate switching tests. Device degradations are observed from these tests, and a design trade-off between the performance and reliability of the SiC MOSFET is concluded. To understand the interactions between devices and circuit parasitics, an experimental parametric study is performed to investigate the influences of stray inductances on the MOSFETs switching waveforms. A small-signal model is then developed to explain the parasitic ringing in the frequency domain. From this angle, the ringing mechanism can be understood more easily and deeply. With the use of this model, the effects of DC decoupling capacitors in suppressing the ringing can be further explained in a more straightforward way than the traditional time-domain analysis. A rule of thumb regarding the capacitance selection is also derived. A Power Electronics Building Block (PEBB) module is then developed with discrete SiC MOSFETs. Integrating the power stage together with the peripheral functions such as gate drive and protection, the PEBB concept allows the converter to be built quickly and reliably by simply connecting several PEBB modules. The high-speed gate drive and power stage layout designs are presented to enable fast and safe switching of the SiC MOSFET. Based on the PEBB platform, the state-of-the-art Si and SiC power MOSFETs are also compared in the device characteristics, temperature influences, and loss distributions in a high-frequency converter, so that special design considerations can be concluded for the SiC MOSFET. Towards high-temperature, high-frequency and high-power operations, integrated wire-bond phase-leg modules are also developed with SiC MOSFET bare dice. High-temperature packaging materials are carefully selected based on an extensive literature survey. The design considerations of improved substrate layout, laminated bus bars, and embedded decoupling capacitors are all discussed in detail, and are verified through a modeling and simulation approach in the design stage. The 200 degree C, 100 kHz continuous operation is demonstrated on the fabricated module. Through the comparison with a commercial SiC phase-leg module designed in the traditional way, it is also shown that the design considerations proposed in this work allow the SiC devices in the wire-bond structure to be switched twice as fast with only one-third of the parasitic ringing. To further push the performance of SiC power modules, a novel hybrid packaging technology is developed which combines the small parasitics and footprint of a planar module with the easy fabrication of a wire-bond module. The original concept is demonstrated on a high-temperature rectifier module with SiC JFET. A modified structure is then proposed to further improve design flexibility and simplify module fabrication. The SiC MOSFET phase-leg module built in this structure successfully reaches the switching speed limit of the device almost without any parasitic ringing. Finally, a new switching loop snubber circuit is proposed to damp the parasitic ringing through magnetic coupling without affecting either conduction or switching losses of the device. The concept is analyzed theoretically and verified experimentally. The initial integration of such a circuit into the power module is presented, and possible improvements are proposed. / Ph. D.

Ce travail de thèse vise la définition et la mise au point de technologies pour l'empilement depuces microélectroniques dans un polymère et connectées électriquement par des viastraversants. Il explore deux voies : l’une de caractère industriel, utilisant une résine époxychargée en billes de silice E2517, l'autre, plus exploratoire, est basée sur l'utilisation de laSU8.Nous avons travaillé sur la mise au point des différentes étapes permettant d'empiler 4niveaux de puces amincies à 80 microns (enrobées) et empilées sur des épaisseurs de l'ordredu millimètre. Le problème du perçage des vias a été abordé et étudié à travers la mise aupoint de procédés d'usinage au laser des résines de type industriel. La métallisation encouches minces de ces trous de facteur de forme élevée (20) a été menée de sorte à atteindredes valeurs de résistance d'accès les plus faibles possibles.Un comparatif des deux voies utilisant la SU8 et la résine E2517 a été effectué et ses résultatscommentés en termes de faisabilité techniques et ses projections dans le domaine industriel.Des tests de fiabilité thermomécaniques ont été menés de concert avec une modélisation paréléments fini afin de valider les résultats des expérimentations réalisées dans le cadre de cetteétude / The subject of this thesis is the definition and development of TPV (Through Polymer Via)technology to stacking chips. The principal objective is to increase the potentialities of thevertical staking (complex IC; multiple I/O...) of Si chips without loss of performance or yield.The technique used consists to surround the IC chips by using particular resin and to fill (withmetallic films) the vertical holes drilled in this material. It explores two ways: one of anindustrial character, using an epoxy resin filled with silica beads E2517, other, moreexploratory, is based on the use of SU8.We worked on the development of different stages to stack four levels of chips thinned to 80microns (coated) and stacked on the thickness of one millimeter. The problem of drilling viashas been discussed and studied through the development of laser drilling processes ofindustrial resins. The thin-film metallization of the holes of high aspect ratio (20) wasconducted in order to reach values of access resistance as low as possible.A comparison of the two channels using SU8 resin and E2517 was carried out and the resultsdiscussed in terms of technical feasibility and its projections in the industrial field.Thermomechanical reliability tests were conducted in conjuction with finite element modelingto validate the results of experiments conducted in this study.

Der ständig steigende Bedarf an Lebensmitteln und Getränken insbesondere in Schwellenländern wie China, Indien und Brasilien fordert von der Verpackungsindustrie eine Leistungssteigerung in gleichem Maße. Um den Durchsatz einer einzelnen Verpackungs- und Füllmaschine unter Beibehaltung von Verpackungsqualität und -form zu steigern, gibt es grundsätzlich zwei Möglichkeiten. Die eine Verbreiterung der Maschine nach sich ziehende Erhöhung der Anzahl der gleichzeitig bearbeiteten Verpackungen, sowie die weitestgehend bauraumneutrale Verringerung der Taktzeit. Letzteres wurde von der SIG Combibloc Systems GmbH, einem der weltweit führenden Systemanbieter von Packstoff und entsprechenden Füllmaschinen für Getränke und Lebensmittel, für eines ihrer Verpackungssysteme in Angriff genommen. Ziel war die Erhöhung des Durchsatzes um 50 % von 24.000 auf 36.000 Verpackungen pro Stunde. [... aus der Einleitung]

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Conventional microelectronic and power electronic packages based on Si devices usually work below 150°C. The emergence of wide-bandgap devices, which potentially operate above a junction temperature of 250°C, results in growing research interest in high-density and high-temperature packaging. There are high-temperature materials such as encapsulants on the market that are claimed for capability of continuous operation at or above 250°C. With an objective of identifying encapsulants suitable for packaging wide-bandgap devices, some of commercial high-temperature encapsulants were obtained and evaluated at the beginning of this study. The evaluation revealed that silicone elastomers are processable for various types of package structure and exhibit excellent dielectric performance in a wide temperature range (25 - 250°C) but are insufficiently stable against long-term aging (used by some manufacturers, e.g., P²SI, to evaluate polymer stability) at 250°C. These materials cracked during aging, causing their dielectric strength to decrease quickly (as soon as 3 days) and significantly (60 - 70%) to approximately 5 kV/mm, which is below the value required by semiconductor packaging. The results of this evaluation clearly suggested that silicone needs higher thermal stability to reliably encapsulate wide-bandgap devices. Literature survey then investigated possible methods to improve silicone stability. Adding fillers is reported to be effective possibly due to the interaction between filler surface and polymer chains. However, the interaction mechanism is not clearly documented. In this study, the effect of Al₂O₃ filler on thermal stability was first investigated by comparing the performance of unfilled and Al₂O₃-filled silicones in weight-loss measurements and dielectric characterization. All test results on composites filed with Al₂O₃ micro-rods indicated that thermal stability increased with increasing filler loading. Thermogravimetric analysis (TGA) test demonstrated that the temperature of degradation onset increased from 330 to 379°C with a 30 wt% loading of Al₂O₃ rods. In isothermal soak test, unfilled and 30-wt%-filled silicones lost 10% of polymer weight in 700 and 1800 hours, respectively. The dielectric characterization found that both Weibull parameters, characteristic dielectric strength (E₀, representing the electric field at which 62.3% of samples are electrically broken down) and shape parameter (β, representing the spread of data. The larger the β, the narrower the distribution) can reflect the thermal stability of polymers. Both of them were influenced by microstructure evolution, to which β was found to be more sensitive than E₀. The characteristic dielectric strength of unfilled silicone decreased significantly after 240 hours of aging at 250°C, whereas that of Al₂O₃/silicone composites exhibited no significant change within 560 hours. The shape parameter of Al₂O₃-filled silicone decreased slower than that of unfilled silicone, also indicating the positive effect of Al₂O₃ micro-rods on thermal stability. Improved thermal stability can be explained by restrained chain mobility caused by interfacial hydrogen bonds, which are formed between hydroxyl groups on Al₂O₃ surface and silicone backbone. In this study, the effect of hydrogen bonds was investigated by dehydrating Al₂O₃ micro-rods at high temperature in N₂ to partially destroy the bonds. Removal of hydrogen bonds impaired thermal stability by increasing the initial weight-loss rate from 0.025 to 0.036 wt%/hour. The results explained the importance of interfacial hydrogen bond, which effectively reduced the average chain mobility, hindered the formation of degradation products, and led to higher thermal stability. The main discoveries of this study are listed below: 1. Al₂O₃ micro-rods were found to efficiently improve the thermal stability of silicone elastomer used for high-temperature encapsulation. 2. Characteristic dielectric strength and shape parameter obtained from Weibull distribution reflected the change of material microstructure caused by thermal aging. The shape parameter was found to be more sensitive to microscale defects, which were responsible for dielectric breakdown at low electric field. 3. Hydrogen bonds existing at filler/matrix interface were proven to be responsible for the improvement of thermal stability because they effectively restrained the average chain mobility of the silicone matrix. / Ph. D.

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No description available.

The purpose of the study was to generate a knowledge contribution to graphic design. By examining the packaging of two milk and two oat drinks, the aim was to study and reflect on how companies represent sustainability through specific elements in the graphic design. The study is based on theories related to sustainability and packaging design, authenticity, greenwashing, certification of products and related studies. This study was based on qualitative research through visual and comparative analysis. Primary data has been created in the form of image analysis of packaging. The focus was on examining how companies imagine and convey messages about sustainability through the visual design of the packaging. The study has been conducted concerning the theory presented and reality. Consequently, research has become tied to the problematization of theory and study. In combination with theory, the empirical material resulted in a basis for analysis. The study showed that companies usually offer sustainability through certifications, informing consumers about food waste or abandonment of the use of the screw cap. Other things that may contribute to the brand’s perception as sustainable are packaging color and texture, using images associated with nature and information about how companies work with sustainability.