Thesis (M.S. in mechanical engineering)--Washington State University, December 2006. / Includes bibliographical references (p. 49).

Thesis (Ph. D.)--Mechanical Engineering, Georgia Institute of Technology, 2006. / Qu, Jianmin, Committee Chair ; Baldwin, Daniel, Committee Member ; Wong, C. P., Committee Member ; Sitaraman, Suresh, Committee Member ; Jacob, Karl, Committee Member.

Thesis (Ph.D. in Biochemistry) -- University of Colorado, 2006. / Typescript. Includes bibliographical references (leaves 118-126). Free to UCDHSC affiliates. Online version available via ProQuest Digital Dissertations;

Thesis (Ph. D.)--State University of New York at Binghamton, Thomas J. Watson School of Engineering and Applied Science, Systems Science Dept., 2004 / Only abstract available. "At the request of the author, this graduate work is not available for purchase." Includes bibliographical references.

Thesis (MSc Food Sc)--Stellenbosch University, 2015. / ENGLISH ABSTRACT: Cassava flour is recommended for substitution with wheat flour in composite flour for baking. The potential use of cassava flour in the food and pharmaceutical industries is attributed to its gluten-free nature and excellent functional properties. However, optimum packaging solution and storage conditions for cassava flour is critical in maintaining the quality attributes and shelf-life stability during storage. Therefore, this study focused on investigating the effects of package types (plastic buckets, low density polyethylene (LDPE) bags and brown paper bags) and storage conditions (cool condition (15 °C, 90% RH); ambient condition (23 °C, 60% RH); and higher condition (38 °C, 60% RH)) on the functional properties, quality attributes and shelf-life stability of cassava flour (cvs. ‘TME 419’ and ‘UMUCASS 36’) developed at the National Root Crops Research Institute, Umudike, Nigeria. Proximate composition, physicochemical attributes, functional properties, and microbial safety of flour were analysed every 4 weeks for 12 weeks storage duration. Flour stored under cool condition with paper bags became moist and sticky with appearance of mould growth before 4 weeks of storage. However, at the end of 12 weeks storage, a decline in moisture content of 11.00 ± 0.02 and 7.05 ± 0.01% flour of ‘TME 419’ was observed at ambient and higher conditions, respectively. Rate of moisture decline was similar in flour of ‘UMUCASS 36’. A slight decrease in protein content of flour was observed during the 12 weeks storage from 1.9 ± 0.07 to 1.30 ± 0.001% for cv. ‘TME 419’ and 3.0 ± 0.05 to 2.27 ± 0.001% for cv. ‘UMUCASS 36’; however, no significant difference was observed under ambient and higher conditions. Cassava flour packed in paper bags and stored under higher condition (38 °C, 60%) had the highest loss (50%) of carotenoid content from 1.84 ± 0.10% to 0.91 ± 0.08%, while a minimal loss (24%) of carotenoid was observed in flour packed in plastic buckets under ambient condition. The concentration of hydrogen cyanide (HCN) decreased across all treatments and was below the safe cyanide level of 50 µg/ mL for food products. After the 12 weeks of storage, flour packed in plastic buckets had the highest aerobic mesophilic bacterial counts (3.43 ± 0.04 log cfu/ g) followed by flour in LDPE bags (3.37 ± 0.03 log cfu/ g) and paper bags (3.35 ± 0.01 log cfu/ g). No significant difference was observed in the package types; however the counts observed were within the acceptable microbial limit Swelling power (SP), solubility and peak viscosity were used to characterise the changes in functional and pasting properties of cassava flour relevant in food industries. Flour packed in plastic buckets under ambient condition had the lowest swelling power (8.48 ± 0.55%) and peak viscosity (260 ± 0.51 RVU) compared to flour packed in LDPE and paper bags with (9.10 ± 0.13 and 9.32 ± 0.41%) SP and (263.67 ± 4.04 RVU and 302 ± 9.52 RVU) peak viscosity, respectively. The essential minerals (sodium, potassium, copper, and iron) were significantly higher in flour of ‘TME 419’ compared to ‘UMUCASS 36’. In summary, for the production of high grade foods such as bread where higher swelling power and viscosities are required, flour from ‘TME 419’ packed with paper bags under higher condition could be desirable. In addition, for infant formulation, flour from ‘UMUCASS 36’ packed in plastic buckets and stored under ambient condition which best maintained nutritional contents (protein and fat) and had the lowest peak viscosity would be more suitable. Flour from both cassava cultivars could be stored up to 12 weeks duration under ambient and hot tropical conditions using all package types evaluated. However, storage with paper bag under higher condition offers the chances of better shelf -life stability of cassava flour. / AFRIKAANSE OPSOMMING: Daar word aanbeveel dat kassavameel in plaas van koringmeel in saamgestelde meel by gebak gebruik word. Die potensiële gebruik van kassavameel in die kos- en farmaseutiese industrieë word toegeskryf aan die glutenvrye aard en funksionele kenmerke daarvan. Optimale verpakking en stoortoestande is egter belangrik vir die instandhouding van die gehalte kenmerke en raklewe stabiliteit tydens stoor. Daarom is die fokus van hierdie studie op die effek van verskillende tipes verpakking (plastiekemmers, lae densiteits politelien (LDPE) sakke en bruin papiersakke) en stoortoestande (koel toestande (15 °C, 90% RH); omringende temperature (23 °C, 60% RH); en hoër temperature (38 °C, 60% RH) op die funksionele kenmerke, gehalte kenmerke en raklewe stabiliteit van kassavameel (kultivare. ‘TME 419’ en ‘UMUCASS 36’) wat by die Nasionale Wortelgewasse Navorsingsinstituut, Umudike, Nigerië ontwikkel is. Die komposisie, fisiochemiese kenmerke, funksionele kenmerke en mikrobiale veiligheid van meel is elke vier weke tydens die 12-weke stoortydperk ontleed. Meel wat onder koeltoestande in papiersakke gestoor word, word klam en taai en swamme maak by vier weke van stoor ’n verskyning. Teen die einde van 12 weke stoortydperk is daar ’n afname in klammigheid van 11.00 ± 0.02 en 7.05 ± 0.01% in ‘TME 419’ meel by onderskeidelik omgewings- en hoër temperature. Die afname in klammigheid is soortgelyk by ‘UMUCASS 36’ meel. ’n Effense afname in die proteïen inhoud van die meel is tydens die 12- weke stoortydperk vanaf 1.9 ± 0.07 tot 1.30 ± 0.001% by die kultivaar . ‘TME 419’ en 3.0 ± 0.05 tot 2.27 ± 0.001% vir kultivaar ‘UMUCASS 36’ opgemerk. Geen noemenswaardige verskil is egter onder omgewings- en hoër temperature opgemerk nie. Kassavameel wat in papiersakke en onder hoër temperature (38 °C, 60%) gestoor is het die hoogste verlies (50%) aan karotien inhoud vanaf 1.84 ± 0.10% tot 0.91 ± 0.08% getoon , terwyl ’n minimale verlies (24%) by meel wat in plastiekemmers onder omgewingstemperature verpak is, opgemerk is. Die konsentrasie van waterstof hidrosianied (HCN) het tydens alle behandelinge afgeneem en was onder die veilige vlak van 50 µg/ mL vir kosprodukte. Na ’n 12-weke stoortydperk het die meel wat in plastiekemmers verpak is, die hoogste mesofiliese bakterië telling getoon \ (3.43 ± 0.04 log cfu/ g) gevolg deur die meel in die LDPE sakke (3.37 ± 0.03 log cfu/ g) en papiersakke (3.35 ± 0.01 log cfu/ g). Daar was geen merkbare verskil ten opsigte van verpakkingstipes nie; die tellings wat geneem is, was almal binne die aanvaarbare mikrobiale perk. Swelkrag (SP), oplosbaarheid en piek viskositeit is gebruik om die veranderinge in funksionele kenmerke van kassavameel wat betrekking het op die kosindustrie, te ondersoek. Meel wat onder omgewingstemperature in plastiekemmers verpak is, het die laagste swelkrag (8.48 ± 0.55%) en piekviskositeit getoon (260 ± 0.51 RVU) getoon vergeleke met meel wat in LDPE- en papiersakke (9.10 ± 0.13 en 9.32 ± 0.41%) swelkrag en (263.67 ± 4.04 RVU en 302 ± 9.52 RVU) piekviskositeit, onderskeidelik toon. Die belangrike minerale (natrium, kalium, koper en yster) was noemenswaardig hoër in die ‘TME 419’ meel vergeleke met ‘UMUCASS 36’. Ten slotte, vir die produksie van hoëgraad kossoorte soos brood waar hoë swelkrag en viskositeit belangrik is, is In ‘TME 419’ meel onder hoër toestande verpak in papiersakke, die beste keuse. In die geval egter van babakosse is ‘UMUCASS 36’meel wat in plastiekemmers verpak en onder omgewingstemperature gestoor is, en wat dus koswaardes (proteïen en vette) behou en wat die laagste piek viskositeit het, meer geskik. Meel van albei kultivaars kan vir tot twaalf weke onder omgewings- en hoë, tropiese temperature in al die verpakkingstipes wat evalueer is, gestoor word. Stoor in papiersakke onder hoër temperature verbeter egter die kanse op beter raklewe stabiliteit.

The integration of multiple digitally driven processes is seen as the solution to many of the current limitations arising from standalone Additive Manufacturing (AM) techniques. A technique has been developed to digitally fabricate fully functioning electronics using a unique combination of AM technologies. This has been achieved by interleaving bottom-up Stereolithography (SL) with Direct Writing (DW) of conductor materials alongside mid-process development (optimising the substrate surface quality), dispensing of interconnects, component placement and thermal curing stages. The resulting process enables the low-temperature production of bespoke three-dimensional, fully packaged and assembled multi-layer embedded electronic circuitry. Two different Digital Light Processing (DLP) Stereolithography systems were developed applying different projection orientations to fabricate electronic substrates by selective photopolymerisation. The bottom up projection orientation produced higher quality more planar surfaces and demonstrated both a theoretical and practical feature resolution of 110 μm. A top down projection method was also developed however a uniform exposure of UV light and planar substrate surface of high quality could not be achieved. The most advantageous combination of three post processing techniques to optimise the substrate surface quality for subsequent conductor deposition was determined and defined as a mid-processing procedure. These techniques included ultrasonic agitation in solvent, thermal baking and additional ultraviolet exposure. SEM and surface analysis showed that a sequence including ultrasonic agitation in D-Limonene with additional UV exposure was optimal. DW of a silver conductive epoxy was used to print conductors on the photopolymer surface using a Musashi dispensing system that applies a pneumatic pressure to a loaded syringe mounted on a 3-axis print head and is controlled through CAD generated machine code. The dispensing behaviour of two isotropic conductive adhesives was characterised through three different nozzle sizes for the production of conductor traces as small as 170 μm wide and 40 μm high. Additionally, the high resolution dispensing of a viscous isotropic conductive adhesive (ICA) also led to a novel deposition approach for producing three dimensional, z-axis connections in the form of high freestanding pillars with an aspect ratio of 3.68 (height of 2mm and diameter of 550μm). Three conductive adhesive curing regimes were applied to printed samples to determine the effect of curing temperature and time on the resulting material resistivity. A temperature of 80 °C for 3 hours resulted in the lowest resistivity while displaying no substrate degradation. ii Compatibility with surface mount technology enabled components including resistors, capacitors and chip packages to be placed directly onto the silver adhesive contact pads before low-temperature thermal curing and embedding within additional layers of photopolymer. Packaging of components as small as 0603 surface mount devices (SMDs) was demonstrated via this process. After embedding of the circuitry in a thick layer of photopolymer using the bottom up Stereolithography apparatus, analysis of the adhesive strength at the boundary between the base substrate and embedding layer was conducted showing that loads up to 1500 N could be applied perpendicular to the embedding plane. A high degree of planarization was also found during evaluation of the embedding stage that resulted in an excellent surface finish on which to deposit subsequent layers. This complete procedure could be repeated numerous times to fabricate multilayer electronic devices. This hybrid process was also adapted to conduct flip-chip packaging of bare die with 195 μm wide bond pads. The SL/DW process combination was used to create conductive trenches in the substrate surface that were filled with isotropic conductive adhesive (ICA) to create conductive pathways. Additional experimentation with the dispensing parameters led to consistent 150 μm ICA bumps at a 457 μm pitch. A flip-chip bonding force of 0.08 N resulted in a contact resistance of 2.3 Ω at a standoff height of ~80 μm. Flip-chips with greater standoff heights of 160 μm were also successfully underfilled with liquid photopolymer using the SL embedding technique, while the same process on chips with 80 μm standoff height was unsuccessful. Finally the approaches were combined to fabricate single, double and triple layer circuit demonstrators; pyramid shaped electronic packages with internal multilayer electronics; fully packaged and underfilled flip-chip bare die and; a microfluidic device facilitating UV catalysis. This new paradigm in manufacturing supports rapid iterative product development and mass customisation of electronics for a specific application and, allows the generation of more dimensionally complex products with increased functionality.

Creating a Tobacco Free Generation: a Tobacco Control Strategy for Scotland sets out the Scottish Government’s ambition to create a tobacco free generation of Scots by 2034. Smoking initiation occurs primarily in adolescence, and the national preventive strategy is correspondingly structured around a range of measures to reduce the availability, affordability and attractiveness of cigarettes and other tobacco products for children and young people. Primary among these are the increase in the minimum age of sale of tobacco from 16 to 18 years instituted in the UK in October 2007, and the ban on the display of tobacco and smoking related products in shops introduced in the Tobacco and Primary Medical Services Scotland Act 2010. This thesis explores young people’s smoking and cigarette access behaviours in the context of the increase in the age of sale of tobacco from 16 to 18 years in 2007, and their perceptions and representations of cigarette brand image in the context of the impending ban on point of sale displays and in anticipation of the introduction of generic cigarette packaging in the UK. A combination of individual, paired and triadic interviews were undertaken with a total of 60 13-15 year old young people recruited from youth clubs and other third sector organisations in two disadvantaged communities in Edinburgh. Around half the participants were regular smokers – defined as smoking a cigarette a day or more – with the remainder reporting ‘occasional’ or ‘experimental’ smoking, defined as intermittent smoking or having tried smoking on one or more occasions. Interviews focussed on participants’ usual cigarette sources, ability to access tobacco, participants’ favoured cigarette brands and their perspectives on recent legislative measures to reduce the attractiveness of cigarettes and other tobacco products for children and young people. Despite the increase in the minimum age of sale, most participants sourced cigarettes from shops, either directly or through intermediaries, and few reported any difficulties securing regular access to tobacco. Retail purchases were described in terms of a progression from more to less targeted purchasing strategies, with those experiencing difficulties buying cigarettes directly employing a range of strategies to identify and target retailers amenable to selling cigarettes to underage customers. Proxy purchases, i.e. purchases made through intermediaries, represented the predominating mode of acquisition among participants, and were described in terms of a progression from less to more targeted third party recruitment strategies, with older and more experienced regular smokers learning to identify and target particular types of individual for proxy purchases. Participants also had recourse to tobacco from a range of social and illicit sources, including ‘fag houses’, although these were not routinely accessed. The diverse cigarette sources identified by participants were not perceived to be equivalent, however, but were rather represented in terms of the parallel acquisition of a range of smoking related competencies. Participants’ diverse modes of tobacco acquisition, as such, reflected not merely their smoking status, with rates of retail cigarette purchasing increasing with age and regular smoking, but their status as a smoker through building symbolic capital. Participants foregrounded their smoking related knowledge and competencies to frame themselves as more or less ‘autonomous’ smokers. In discussions about participants favoured cigarette brands, participants would similarly foreground their knowledge of a range of perceived brand characteristics to frame themselves as more or less ‘discerning’ smokers. The importance of cigarette access and branding in shaping participants’ smoking identities has clear implications for smoking prevention policy, in terms of challenging the implied equivalence between the diverse cigarette sources available to young people routinely implied in the youth access literature and underscoring the importance of limiting the visual cues in cigarette packaging and point of sale advertising that facilitate the continued use of cigarettes as an ‘identity tool’.

Master of Science / Department of Grain Science and Industry / Sajid Alavi / There is a renewed focus on biodegradable polymers in packaging applications due to environmental concerns associated with conventional plastics. Melt extrusion was used to synthesize nanocomposites from poly (lactic acid) (PLA) or poly (butylene succinate) (PBS) blended with natural nanofillers — chitin whiskers (CHW, 1-5%), nanocrystalline cellulose (NCC, 1-5%) or lignin-coated nanocrystalline cellulose (LNCC, 3%). Transmission electron microscopy and x-ray diffraction indicated that the natural nanofillers were uniformly dispersed in the polymer matrix. For PLA based nanocomposites, differential scanning calorimetry showed a decrease in change of heat capacity at glass transition (ΔCp) with increased nanofiller addition, indicating greater confinement of polymer chains. For PBS based nanocomposites, nanofillers acted as nucleating agents and promoted recrystallization of polymer as reflected in increase of degree of crystallinity (Xc) from 65.9-66.8 to 75.6%. By addition of NCC and CHW, tensile strength (TS) of PLA based films increased from 50.2 MPa to 70.9 MPa and 52.1 MPa, respectively, while TS of PBS increased from 23.2-24.9 MPa to 32.9 MPa and 43.6 MPa, respectively. Elongation at break (E%) of nanocomposite films ranged from 9.1 to 15.3, and in general decreased with addition of nanofillers. LNCC did not significantly improve mechanical properties of PBS and PLA films. Additionally, 3% NCC addition reduced oxygen transmission rate (OTR) of PLA from 209.9 to 180.8 cc/m[superscript]2/day, which further reduced to 109.3 cc/m[superscript]2/day by adding compatibilizer methylene diphenyl diisocyanate (MDI, 4%). Water vapor transmission rate (WVTR) of PLA also reduced from 44.4 to 28.6 g/m[superscript]2/day with 3% NCC and 4% MDI addition. Similarly OTR and WVTR of PBS decreased from 737.7 to 280 cc/m[superscript]2/day and 83.8 to 49.4 g/m[superscript]2/day, respectively with 3% NCC. Use of 4% MDI further reduced OTR and WVTR to 23.8 cc/m[superscript]2/day and 30.8 g/m[superscript]2/day, respectively. Use of starch can potentially reduce the costs of bio-based nanocomposites films. Up to 40% starch was incorporated during synthesis of PLA and NCC nanocomposites using solution mixing method. Addition of starch decreased TS from 35.8 MPa to 18.4 MPa and E% from 8.3% to 6.0%. Use of NCC (1%) and MDI (4%) improved the mechanical properties to a certain extent.

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