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Growth option for a traditional SME in the food and beverage industry – A case of Loke Kee biscuits
No full textLoke Kee is a well-established Malaysia small and medium-sized enterprise (SME) with a rich history spanning over 77 years since its inception in 1947. Renowned for its expertise in producing traditional Chinese cookies, LK has established a reputation for its superior product quality and unwavering commitment to excellence. To ensure the safety and integrity of the product, LK’s manufacturing facility is certified by Halal Jakim and has attained food safety qualification such as Food Safety Management System (FSSC) 22000 and Hazard analysis and critical control point (HACCP). These certifications have solidified the company’s market position by demonstrating its commitment to quality and compliance
A study on public perception and attitudes towards electronic waste management in Singapore
No full textElectronic waste (e-waste) is a growing environmental challenge worldwide, particularly in highly urbanized nations like Singapore, where rapid technological advancements and high consumer demand contribute to increasing volumes of discarded electronic products. This study examines public perceptions, attitudes, and behaviors toward e-waste management in Singapore, focusing on the influence of demographic factors, psychological determinants, and educational interventions. Using a quantitative research approach, the study finds that demographic factors have a limited impact on e-waste management behaviors, while psychological factors show no significant influence, underscoring the complexity of translating positive attitudes into actionable behaviors. Educational interventions demonstrate moderate effectiveness in promoting responsible smartphone disposal but have a limited impact on other e-waste behaviors. These findings highlight the need for a multifaceted approach to e-waste management, integrating improved infrastructure, targeted educational campaigns, and policy support to bridge the gap between awareness and action. Key recommendations include enhancing accessibility to e-waste recycling facilities, expanding school-based and community education programs, and leveraging social norms to foster a culture of environmental responsibility. This study provides valuable insights for policymakers, industry stakeholders, and environmental advocates seeking to strengthen e-waste management frameworks in Singapore and beyond
Observational Constraints on Primordial Black Hole Dark Matter
Get PDFIn spite of compelling evidence for its existence and great experimental efforts to detect it, the nature of dark matter remains unknown. One scenario is that some or all of the dark matter consists of black holes formed from the collapse of highly overdense regions in the early Universe. Observational constraints on these `primordial black holes' (PBHs) appear to exclude PBHs from making up all of the dark matter unless their mass, MPBH, lies in the range 1017 g ≲ MPBH ≲ 1022 g, often known as the `asteroid-mass window'. In this thesis we investigate the impact of assumptions made when calculating observational constraints on PBHs.
Firstly, we consider the effect of PBH clustering on microlensing constraints. Clustering of PBHs occurs to a greater extent than for standard cold dark matter on small scales. For PBHs formed from the collapse of large gaussian fluctuations, we find clustering has only a small effect on microlensing constraints even for very massive PBHs (MPBH ∼ 103M⊙) for which the effect of clustering is largest.
Constraints on PBHs are usually obtained assuming all PBHs have the same mass, though accounting for critical collapse shows they would have an extended mass function. A lognormal fit has been widely used to parameterise the PBH mass function, though recent work has shown that other functions provide a better fit. We recalculate both current and prospective future constraints on PBHs with these improved fitting functions, to assess to what extent the asteroid-mass window remains open. For current constraints, the window is narrowed, though there remains a region where PBHs can make up all of the dark matter. Future constraints from evaporation and microlensing may together exclude all of dark matter being made of PBHs if the PBH mass function is sufficiently wide
Growing Classifications: Widths, Ehrhart Theory and Spherical Geometry
Get PDFThis thesis focuses on three classifications of convex polytopes, which are separate, but the methods of each influences those that follow. There are links to combinatorial algebraic geometry throughout, particularly to toric and spherical geometry. This is most explicit in the third project, which is additionally a classification of certain spherical varieties.
In the first project we introduce the multi-width of a polytope, which is an extension of its lattice width. We study the classification of lattice simplices by their multi-width in dimensions two and three. This is motivated by computational questions in toric geometry. We completely classify lattice triangles by their multi-width and also classify lattice tetrahedra of small multi-width.
The second project concerns the Ehrhart theory of rational polygons. The Ehrhart theory of lattice polygons is already well understood and here we make steps towards a similar understanding of denominator two polygons. We classify denominator two polygons containing up to four lattice points, including a description of infinite families of polygons with no interior points. Using this data, we completely classify the Ehrhart polynomials of denominator two polygons with zero interior points and find three sharp bounds on the coefficients when there are interior points.
In the final project we study spherical varieties, which generalise toric and flag varieties. We discuss isomorphisms between spherical varieties and describe a class of lattice automorphisms which are induced by isomorphisms of spherical varieties. We define a normal form for lattice polytopes up to this group of automorphisms. This normal form is vital to our classification of spherical canonical Fano four-folds. Like toric Fano varieties, spherical Fano varieties correspond to polytopes. Therefore, we can classify the varieties by classifying the corresponding polytopes
Metal-carbon nanocatalysts for electrochemical CO2 reduction
No full textThe work in this thesis investigates graphitised nanofibers as a support medium for metal catalysis for the electroreduction of CO2. They provide a nanotextured surface in which metal catalysts can be stabilised and the highly conductive properties of graphitised nanofibers and high surface area to volume ratio make them an ideal support for the electroreduction of CO2.
Firstly, graphitised nanofibers magnetron sputtered with Cu was tested for its electrocatalytic activity towards the CO2 reduction reaction. Using a correlative microscopy and electroanalytic approach, the catalysts properties were directly linked with in-situ morphological changes. As such the catalyst worsening properties over time was linked with changes to the catalyst itself, with emergence of single atoms of Cu and increasing nanoparticle size changing active centres and therefore selectivity.
To study another Cu magnetron sputtered catalyst in finer detail, identical location transmission electron microscopy was performed to elucidate mechanisms of catalyst reconstruction and degradation in-situ. Allowing for the Cu nanoparticles to be monitored during an accelerated CO2 reduction reaction with information gathered on not only the shape, size but the Cu-support interface. Herein, the catalysts behaviour can be monitored closely and as such the migration of Cu was found to be high on graphitised nanofibers as well as a transient mechanism of desorption of Cu and redeposition to erode Cu centres forming a thermodynamically stable catalyst. The Cusupport interface was found to be key, as the catalyst undergoes CO2 electroreduction this interface matures and forming intimate contact with the graphitised nanofiber support.The catalysts activity towards CO2 reduction was also explored, with an interesting relationship observed between the CO2 reduction reaction and hydrogen evolution reaction.
Another method for metal deposition was investigated, the electrodeposition of Sn was used to create a graphitised nanofiber coated catalyst with a unique microstructure due to the graphitised nanofibers. The catalysts activity towards the electro reduction for CO2 was evaluated and conditions optimised by increasing electrolyte concentration, in which an optimum was found. The optimum condition found was used for longterm catalysis and observed changing catalytic behaviour occurring during catalysis.
The in-situ changes of the catalyst were investigated using a correlative electron microscopy and electroanalytical approach. Revealing a known degradation mechanism to be responsible for the change in catalytic activity, but unlike previous literature examples, this improves catalytic properties over time, reaching a maximum. As such we found that the in-situ mechanism responsible for changing catalytic activity benefits this catalyst due to the nano-textured surface of the graphitised stabilising the Sn catalyst.
Lastly, to improve the catalytic activity of the electrodeposited Sn catalyst, a coelectrodeposition method was used to form a Cu/Sn bi-metallic. The co-deposition of both Cu and Sn revealed a unique morphology of the catalyst with nanostructured deposits on the graphitised nanofibers. The inclusion of Cu into the Sn catalyst was evaluated with an electroanalytical approach to evaluate the activity and formation rate of products from the CO2 reduction reaction with the previously optimised conditions for the Sn catalyst
Bio-sourced novel monomers and polymers for plastics sustainability
Get PDFThis thesis details the synthesis of several novel monomers from biomass chemicals such as terpenes and furfural. Several synthesis routes were explored to produce a broad spectrum of functional groups suitable for polymerisation, such as hydroxyls, carboxy acids, epoxides, lactones, and methacrylate.
In chapter two, terpene-derived monomers were synthesised via the derivatisation of -pinene, -pinene, limonene and geraniol. This resulted in novel monomers with diols, hydroxy-carboxylic acids, di-carboxy acids and epoxides.
In chapter three, a six-membered ring lactone monomer was synthesised from furfural.
Some of these monomers have been used in synthesising sustainable polyesters and polymethacrylate, which contain a unique cyclohexane ring or a double bond in their backbone, making them suitable for post-polymerisation modification. The functionalisation of limonene, -pinene, -pinene and geraniol has enabled the synthesis of several renewably-sourced monomers to form terpene-derived polyesters. Step growth homo-polymerisation of diols, diacids and hydroxy-acid yields low molecular weights of novel polyesters. The limonene diol derivatives are demonstrated to function as co-monomers alongside a renewable diacid. The resultant polyesters display Mns of up to 8400 g/mol. -Pinene was used to synthesise dialcohols, which served as co-monomers with a renewable diacid, enabling the synthesis of two novel polyesters
AGRONOMIC BIOFORTIFICATIONS OF TEFF (ERAGROSTIS TEF): FROM SOIL PROPERTIES TO ZINC FERTILIZERS APPLICATION STRATEGIES IN ETHIOPIA
No full textMost Ethiopian soils are low in plant available zinc (Zn), and this varies with the landscape position and soil type. This affects grain Zn loadings and subsequently human health when diets are primarily based on cereals grown on these soils. The link from soil – plant - human is strong and unlocking Zn availability in the soil helps efforts for improved nutrition and health in Ethiopia. Therefore, a better understanding of soil properties (Chapter 3 and 4) and devising best fit fertilizer application strategies (Chapter 5 and 6) are important for increasing grain Zn loading by crops, biofortifying crops with Zn.
Two sets of laboratory experiments were run on representative soil samples collected from the different landscape positions in the Amhara Regions for their capacity to retain and release Zn from stock solutions to identify the main soil factors driving Zn availability (Chapter-3). A subsequent estimation of the potential availability of Zn from the soil and fertilizer applications and link with the actual grain Zn concentrations through developing predictive models based on soil properties and soil applied Zn fertilizer (Chapter-4) were encouraging. Knowing a few soil parameters, such as soil pH, SOC, Mehlich-3, clay, and the amount of fertilizer applied, has the potential for predicting the actual grain Zn concentrations of maize, teff and wheat up to 52% enabling a tailored fertilizer application to be made based on the target grain Zn concentrations of crops.
Two sets of greenhouse experiments were run to devise fertilizer applications strategies (4Rs) for improved teff grain Zn loading on the five dominant soils in Ethiopia. This study proved that the current 5 kg Zn for soil application is not enough to increase grain Zn loading of teff, and a minimum of 15 kg is needed for soil (Chapter-5) and 1.25 kg for foliar at tillering or both at tillering and flowering stages (Chapter-6). This helps improve nutrition through biofortifying teff with Zn. Increased grain Zn concentrations of teff through the best fertilizer application strategies with the decreases in the PA:Zn ratios across the soil types implying that bioavailability= of the grain Zn to human improves as compared to the absence of Zn applications, control treatments. Therefore, a better understanding of soil properties coupled with best-fit Zn application strategies would help the biofortification of crops grown on low Zn soils in Ethiopia
Fabricating functionally superior starch based products with fractionated Plantago seed mucilage
Get PDFStarch plays a crucial role in nutrition and food production, serving as a primary source of energy in diets worldwide. Foods like potatoes, rice, and whole grains represent the base of a meal, serve as carbohydrate source, and contribute to overall health by promoting satiety and aiding digestion. Furthermore, starches are versatile in food production; they serve as thickening agents in cooking and because their behaviour varies widely in nature and they are conducive to further modifications, starches are integral to various processing applications beyond food, including pharmaceuticals and paper manufacturing. Due to its relatively low price, it is easily accessible around the globe, and its importance is studied from a culinary aspect, as well as health and metabolism. Despite its significance, starch consumption brings certain challenges. Firstly, starch and starch-based products are usually overprocessed and lack fibre which is essential for metabolic health. Fibre can reduce blood glucose spikes (a consequence of eating simple carbohydrates and starch), act as prebiotics to maintain gut microbiota, reduce cholesterol and associated risk of cardiovascular illness, and fibre contributes to satiety and healthy eating habits. The addition of fibre and hydrocolloids in starch has long been a subject of research, and improvement of functional properties has been observed by measuring physicochemical and functional properties, such as digestibility (in vitro and in vivo), texture analysis, thermal analysis, microstructure, rheology, pasting properties, and many more. Elucidating mechanisms of interaction between starch and fibre is extremely important as it helps to rationalize their use. Therefore, the aim of this thesis was to explore the addition of novel fibre materials to different types of starch, namely fractionated fibre from seeds of the Plantago genus. The most utilised and commercially relevant Plantago species is Plantago ovata, also known as psyllium. P. ovata is myxospermous plant, meaning that its seeds produce a gel-like coating called mucilage when wet. Importantly, in its dry form, P. ovata mucilage is essentially a layer of dried fibre that can be mechanically separated from the seed. Psyllium husk is often used as a fibre addition to many product categories but its functionality is fairly narrow which has led researchers to explore novel processing methods. Simple fractionations, where the mucilage polysaccharides are extracted with sequential steps usually involving temperature solubilisation and simple separation methods, have gained research interest as they can produce fibres with varying functional properties from the same starting material. Furthermore, the Plantago genus has over 200 species, many of them myxospermous, though underexplored, which prompted us to raise and answer certain research questions. Are there fibre fractions from other Plantago species which are comparable to P. ovata, and can we utilise their gel properties? How would their rheology differ? Would their addition in certain starches change the overall starch profile? Would those changes be transferable to food products? These questions helped shape topics and the flow of this thesis, which is presented in Fig. 1.1.
Chapter 2, a comprehensive literature review, brings an overview of nutritional and health benefits of P. ovata husk, as well as detailed summaries of extraction methods and rheological characterization. Challenges of psyllium husk application are described, which often coincide with the benefits of its high viscosity and proposed five solutions to said challenges with high level rationale.
Chapter 3 focuses on characterization of fibre fractions from four Plantago species (P. ovata, P. lanceolata, P. turrifera, P. drummondii), as one of the solutions proposed in Chapter 2 was to exploit natural variation in Plantago, and study the fractionation behaviour of underexplored species to discover additives with even broader functionality than could be gained from fractionating P. ovata alone. We compared corresponding fractions from each species and found that fractions between species shared key chemical similarities but differed in their rheological behaviour. Interestingly, P. turrifera and P. drummondii produced fractions with extremely high resilience under rheological deformation compared to P. ovata, which could be useful in product formulation.
Chapter 4 showed how inclusion of fractions characterised in Chapter 3 affect the quality (colour, freeze-thaw syneresis, rheology, and starch hydrolysis) of rice starch. This study revealed that fibre most likely disrupted the amylose network in gelatinised rice starch, but fibre addition improved viscoelastic properties under stress. Interestingly, Plantago fibre fractions increased starch hydrolysis rate in all but one composite gel, which was identified as promising candidate for the improvement of structure and digestibility of starch gels.
Chapter 5, therefore, explores in-depth microscopic and rheological characterization of the promising fraction identified in Chapter 4 when combined with five starches of varying properties at different storage conditions. In this chapter, we propose different interaction mechanisms between P. ovata fraction and starches, which were mostly dependent on amylose content of the starch.
Preceding chapters were highly fundamental though we were also interested in exploring fractionations with modifications that might make them more industrially relevant. Chapter 6 presents a one-step fractionation of commercial psyllium husk, where our aim was to study fractionated fibre application and its outcomes which would be industrially relevant. The main finding of this chapter was that the simple fractionation produced two psyllium fractions that had highly contrasting effects on corn starch with varying amylose content, and that those effects were also temperature dependent. This may open the door for adjusting food processing based on viscosity of individual ingredients and texture and digestibility properties of the final product.
Continuing the more application-driven component of this thesis, Chapter 7 investigates the addition of P. ovata and P. turrifera fibre, identified in Chapters 3 and 4 as having promising rheological differences, in gluten-free rice bread. We studied the effect of P. ovata and P. turrifera fibre addition on dough behaviour and texture, baking quality of breads, as well as the appearance, texture, storage behaviour of bread and its digestibility in in vitro analysis. Our goal was to see if observations from previous chapters would be transferable in complex food products, such as bread, and if the fibre addition improve quality of gluten-free bread. We showed that comparable fractions from alternative Plantago species might be suitable alternatives to P. ovata, whose supply is becoming more and more volatile.
Finally, Chapter 8, provides an overview of the main findings and avenues for future research
Analysing Organosulfur-based Additives to advance Lithium Sulfur Batteries and achieve superior cell performance
No full textThe development of batteries is a crucial interim goal against climate change, and with lithium-ion batteries approaching their limits, new technologies are needed. Lithium-sulfur batteries (LSB) have enormous potential: sulfur is environmentally benign, economic, abundant, and most importantly, has a high theoretical energy density of 1675 mAh/g. Out of all next-generation battery types, LSB technologies have the highest technology readiness level - a system used to assess a technology's maturity. A range of challenges have still to be tackled, such as poor electrical conductivity in the positive electrode, slow conversion kinetics, dendrite formation, and the polysulfide shuttle effect. This project seeks to develop novel electrolyte additives, and explore new ways of enhancing LSB cell performance.
The challenges revolving around upscaling cell production are often overlooked in material development. While the underlying chemistry is identical, the engineering aspects often tremendously impact the cell performance. In Chapter 2, two cell formats will be compared, and hypothesis tests will be applied to enhance galvanostatic cell data reliability.
In Chapter 3, a new approach for developing targeted additives using molecular organosulfur-based compounds will be proposed. Complementing bottom-up and top-down methodologies are combined to accelerate additive design by establishing structure-property relationships, with the ultimate goal of enabling the efficient development of additives with tailored properties.
In Chapter 4, various electrochemical and spectroscopic techniques are employed to analyse the composition of two thiophosphate-based additive mixtures. Galvanostatic cell cycling is conducted to investigate potential cell performance-enhancing properties,
Chapter 5 investigates the potential of ammonium diethoxydithiophosphate (Additive DEDP) in LSB technologies. In continuation of the previous chapter, Additive DEDP and its interaction with S8, Li2S8, and Li2S sulfur species endemic to LSB technologies will be assessed. Special attention will also be given to the complex chemistry of polysulfides in correlation to cell performance
Attention-driven scenography
No full textGame engines now find use beyond video games for virtual production in television, film, and other fields. Streaming services also use these engines to provide games and interactive media for new audiences. While interactive media become more accessible via these technologies, game engines still hold novel narrative design opportunities. They offer significant possibilities in the production of interactive narrative experiences in rich virtual environments. Interactive and adaptive narrative spaces can enhance immersion and provide experiences other media do not. Yet branching narrative remains a common design pattern.
This research asks what novel forms of interactive narrative design are possible with game engines, via environmental storytelling. It asks what roles exist for the audience between viewer and player, and how new approaches to interaction and narrative design can provide experiences that react to user attention in virtual environments. It explores what other non-linear forms of narrative are possible, with a focus on those involving environmental storytelling in virtual spaces, organised to be experienced spatially rather than temporally. An overview of existing forms and key examples is provided.
Attention-Driven Scenography (ADS) is presented as a novel form of environmental storytelling-focused interactive digital narrative design. ADS tracks user attention via the proxy of camera view in a virtual environment, and uses this to provide tacit and implicit interactions with virtual objects that respond in the moment, over time, and ahead of time, to the amount of attention given, resulting in engaging adaptive environmental and thematic storytelling. ADS offers the possibility of customising environments and scenes over time to adapt an experience to what seems to be of interest to the user based on their attention.
The primary research consists of the design work that informed the ADS design concept, and the formalisation of the concept in a plugin for the Unity game engine. Example experiences were created and evaluated through observations and user studies to assess ADS as a novel form of interactive storytelling. Studying ADS through the experience Woolgatherer showed that participants responded positively, though questions were raised about user agency, consistent interaction patterns, and induction for ADS mechanisms.
Future design work is needed, particularly in balancing user agency with attention and memory in a complex interactive environment, and the complexity of authoring a cohesive but adaptive experience. With the ADS software plugin, engaging others in its use may provide further useful assessment of the concept. In conclusion, there is an interesting tension in using attention to drive a spectrum of interactions from explicit through tacit to implicit, and situating users as percipients in a complex position of agency where their influence is stronger than they realise. ADS is emerging as a useful design concept for complex adaptive environmental storytelling across virtual time and space
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