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    Methodology independent CASE tool : a prototype : a thesis presented in partial fulfilment of the requirements for the degree of Master of Arts in Computer Science at Massey University
    (Massey University, 1994) Clark, Paul
    The object-oriented (OO) movement is at present split into many factions and as a result no standard has been defined. A direct consequence of this lack of consensus is that there are no mature CASE tools available. Current object-oriented CASE tools are methodology dependent. They are not driven by the need to enable the successful construction of OO software but rather to sell a particular methodology (at this time there are more than 30 different OO methodologies. Forcing the developer to use a particular methodology constrains his/her ability to select the most appropriate problem representation. To address these problems a research project aiming at the development of a methodology independent OO CASE tool has commenced. The thesis is the first stage in the tool development. It addresses two main problem areas of this research project: • The development of a customisable user interface which utilises an abstract notation definition language. • Support of the implementation phase of OO software. A language which facilitates abstract definitions of graphical notations and the human computer interaction with them has been developed. The implemented graphical user interface uses the developed language to allow arbitrary notations and dialogues for OO models to be described and modified without recompilation of the CASE Tool. Re-engineering facilities have been designed to allow a user to generate an OO model from existing OO source code. Automatic layout generation has been investigated and several auto-routing algorithms applied. The current tool generates Coad and Yourdon diagrams from C++ source code. The user can update and navigate the C++ source via the created OO model. Based on the thesis results two papers were presented at the International conference on Object Oriented Information Systems in London, December 1994. A collaborative research has also commenced with the University of Technology, Sydney.
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    Biofilm formation by B. licheniformis isolated from whey protein concentrate 80 powder as a potential source of product contamination : a thesis presented in partial fulfilment of the requirements for the degree of Doctor of Philosophy in Food Technology at Massey University, Palmerston North, New Zealand
    (Massey University, 2018) Md Zain, Siti Norbaizura binti
    This study aimed to examine biofilm formation of Bacillus licheniformis isolated from whey protein concentrate 80 (WPC80) as a potential source of contamination in the manufacture of WPC. Six WPC80 powder samples from one whey processing plant in New Zealand were used in this study. Six Bacillus species including (percentage of isolates in brackets) B. licheniformis (66%), Bacillus cereus/Bacillus thuringiensis (18%), Bacillus subtilis (4%), Bacillus pumilus (4%), Paenibacillus glucanolyticus (2%) and Lactobacillus plantarum (6%) were identified using colony morphologies, biochemical tests, species specific PCR and 16S ribosomal DNA gene sequencing and subsequent analysis using the BLAST and Seqmatch databases. Preliminary screening for biofilm formation by the predominant contaminant, B. licheniformis using a microtitre plate assay with the bacteria grown in laboratory medium tryptic soy broth (TSB) at three different temperatures (30°C, 37°C and 55°C) showed most biofilm formation at 37°C with 9/33 isolates forming strong biofilm. In total 13/33 isolates formed strong biofilm at three different temperatures on the polystyrene microtitre plate surface. Subsequent tests for biofilm formation on stainless steel (SS) showed an increased frequency of biofilm formation with 32/33 strains forming strong biofilm in TSB at 37°C. This demonstrates the limitation of the microtitre plate assay for screening for biofilm formation and suggests that biofilm growth of B. licheniformis favours a SS surface. The attachment and biofilm formation was further investigated using SS coupons and reconstituted whey medium at different concentrations (1%, 5%, and 20%). The best medium for B. licheniformis isolates to form biofilm on SS at its best growth temperature (37°C) was 1% reconstituted WPC80. Interestingly, when 1% reconstituted WPC80 was supplemented with lactose and minerals (mainly calcium and magnesium) to replicate the composition of Mozzarella cheese whey before ultrafiltration (UF), the B. licheniformis biofilm counts increased at least by one log. The production of protease enzyme, extracellular polymeric substances (EPS) and nitrate reduction by B. licheniformis showed the potential of B. licheniformis to influence the quality of dairy products. Biosurfactant production by B. licheniformis identified as lichenysin consisting of lipopeptide was detected and this may influence biofilm formation on SS. The inability of the B. licheniformis isolates to ferment lactose as their major carbon source was confirmed by lactose fermentation tests and shows that B. licheniformis is not ideally suited to a dairy environment. The B. licheniformis vegetative cells were found to be heat resistant with a < log10 reduction at the three temperatures tested; 72oC, 75oC and 80°C during 15 s, 30 s and 60 s heating intervals. In order to thrive in a dairy system, synergistic interactions with other microflora were investigated as a possible mechanism to use lactose that has been broken down by other microflora. Lactobacillus plantarum (L. plantarum), another isolate from the WPC80 samples, has the ability to produce glucose and galactose from lactose. This was grown with each of two B. licheniformis isolates (E30C11 and F30C02) with different abilities to form biofilm. Interestingly this did not enhance the growth of B. licheniformis suggesting that another carbon source, most likely whey protein, must provide the energy source for this bacterium in a whey environment. A review of the WPC80 processing plant showed the UF membranes had the largest surface area (3500 – 7500 m2), providing most potential for biofilm growth. However, UF was run at 10°C, too low for the growth of B. licheniformis which has a minimum growth temperature of 20°C. The hypothesis that sections of the processing plant before the UF step are the sites for B. licheniformis biofilm growth was supported by analysing several samples from the raw whey balance tank, clarifier, thermaliser and separator where 7 B. licheniformis strains were isolated. This shows that B. licheniformis is present at several early stages of WPC processing, with the most likely areas for growth being the certain sections of the clarifier, thermaliser and the separator where temperatures are close to the best growth temperature for this bacterium (37°C). Preventing B. licheniformis contamination of WPC needs to focus on adjusting the conditions in these sections of the processing plant to limit biofilm growth. Keywords: dairy, Bacillus species, L. plantarum, lichenysin, stainless steel, membrane processing plant.
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    Development of a lactic casein based savoury flavour product : a thesis presented in partial fulfilment of the requirement for the degree of Master in Food Technology at Massey University, Manawatū, New Zealand
    (Massey University, 2016) Chen, Ting
    The aim of this project was to develop a casein-based hydrolysate formulation that has higher savoury flavour and is more cost effective than an existing commercial savoury hydrolysate. From the literature review, bovine casein protein has the most savoury flavour potential of all proteins due to its high glutamic acid and glutamine content. The symbol of savoury flavour is cheese which is made from casein protein in the western world. The main reaction resulting in cheese savoury flavour development is proteolysis where casein protein breaks down to peptides by protease and free amino acids by peptidases. Two different systems were designed to be based on those reactions in order to generate maximum free glutamic acid during the experiments. The enzyme substrate was a 10% lactic sodium caseinate slurry, which is the foundation of the experiments. With the first system, an enzyme preparation with protease functions was added first and followed by an enzyme preparation with peptidase functions. With the second system only one enzyme preparation with both protease and peptidase activity was added for each trial. From the results, it was found that none of the enzyme combinations from either system were able to achieve the same amount of free glutamic acid as the existing commercial product (31.95 mg/g of protein) within 24 hours. However, multiple options would have had equivalent free glutamic acid if the free glutamine content could be converted to L-glutamic acid using a glutaminase. Flavorzyme 1000L from system one was selected to be the option combining with glutaminase based on its cost, microbiology and chemistry process results. Two different dosages (0.25% and 0.5%) of Glutaminase C100SD were trialled with 2% of Flavorzyme 1000L. From the degree of hydrolysis, free amino acid content, molecular weight profile and residual glutamine results, there were almost no difference between the two trials. The final formulation of Flavorzyme 2% and 0.25% Glutaminase C100SD had 48% more free glutamic acid than the existing commercial control. It also achieved a 33% ingredient cost reduction. Most importantly, the final formulation resulted in a 22.5% final ingredient cost reduction per kilogram based on the same commercial cost model as the control. An informal sensory panel indicated that the new savoury hydrolysate was more savoury and less bitter than the existing commercial control.
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    Investigations on the emulsifying properties of egg white protein : a thesis presented in partial fulfilment of the requirements for the degree of Master of Food Technology at Massey University, Auckland, New Zealand
    (Massey University, 2018) Onyemachi, Amarachi Delight
    Egg white proteins (EWP) have excellent foaming and gelling functional properties. However, their emulsifying properties are considered poor when compared to soy proteins or milk proteins. Some studies have attributed the poor emulsifying properties to the hydrophobic amino acid groups buried deeply in the interior of the protein conformational structure which is crucial for emulsification. Several methods, such as heat treatment, acid/acid-heat treatment, Maillard reaction, phosphorylation and enzymatic hydrolysis, have been used by some researchers to improve the emulsifying properties of EWP. Preliminary experiments carried out in this study showed that oil-in-water (O/W) emulsions prepared with egg white liquid (EWL) generated lots of visible large aggregates, which no other study has reported. Therefore, it was important to investigate the factors responsible for the formation of these aggregates. Investigations into improving EWP's emulsifying properties could offer opportunities in developing unique and well-defined egg white-based emulsions. The objective of this research project was to produce egg white emulsions with little or no aggregates. This thesis comprises three main parts. The first part focused on the effects of pH and heat treatment on protein aggregation and partial denaturation of proteins in EWL. The second part investigated the effects of heat treatment, oil concentration and protein concentration on the reduction of large visible aggregates in emulsions prepared with EWL. The third part studied the effect of enzymatic hydrolysis on the degree of hydrolysis and emulsifying properties of EWP hydrolysates. The emulsifying properties of original EWP and EWP hydrolysates were characterised in terms of size and zeta (ζ)-potential of emulsion droplets and emulsion stability (e.g. turbidity, microscopic examination and phase separation). Firstly, an experimental study was carried out to evaluate the effect of pH on protein aggregation and precipitation in EWL containing different protein concentrations (0.5, 1, 2, 3, 4, 5 and 10% w/w). It was found that at all the protein concentrations used and at pH less than around 5, ζ-potential values were all positive but decreased as pH increased from 2 to 5. At pH 5, ζ-potential was close to zero (this is the pI of most egg white proteins), while, at pH levels above 5, ζ-potential became negative and increased as pH increased from pH 5 to 11. The spectral absorbance (turbidity) of emulsion samples was also measured at 600 nm which revealed that for all protein concentrations, turbidity was observed to be higher at acidic pH of 3, 4 and 5, indicating the aggregation of EWP. At alkaline conditions of pH 7, 8, 9 and 10 the EWL solutions remained to be transparent. The effect of heat treatment and holding time on the denaturation of EWP in EWL was also studied at different temperatures (57-62oC) and heating times (0-19 minutes). Higher turbidity due to protein aggregation was observed as temperature increased from 57 to 62oC and the heating time increased from 5 to 19 minutes. It is therefore concluded that EWL can be safely pasteurized with little or no denaturation or aggregation at around 57-58oC for less than 5 minutes. At 60oC, it was observed that EWL began to thicken and after 5 minutes coagulation and gelation occurred rapidly. Studies were also carried out to determine the cause of visible large aggregates formed in emulsions prepared with EWL using various factors, such as heat treatment, oil concentration and protein concentration. It was found that heat treatment (60oC for 30 minutes) of 1% (w/w) EWP solution prior to homogenisation had no effect on reduction of aggregates in emulsions containing 5, 10, 15 and 20% (w/w). However, the formation of aggregates was reduced significantly as oil concentration was reduced to 5%. Therefore, the effect of lower oil concentrations (1, 3, 5, 6, 7 and 10% w/w) on the formation of aggregates in emulsions prepared with 1% or 3% EWP concentrations was also investigated. Little or no visible aggregates were formed when emulsions were prepared with 1% EWP and ≤ 5% oil or 3% EWP and 1% oil. Therefore, the results indicated that both protein and oil concentrations played a significant role in the formation of visible aggregates in emulsions prepared with EWP as an emulsifier. The effect of EWP concentrations (0.1, 0.3, 0.5, 0.8, 1 and 2% w/w) on the formation and properties of 5% oil emulsions at ~pH 8 was then investigated. It was discovered that little or no aggregates were produced in emulsions when prepared at 0.1-1% EWP while large aggregates were formed at 2% EWP concentration. The size of emulsion droplets was observed to increase significantly from 242.1 to 703.7 nm as protein concentration increased from 0.1 to 2%. ζ-potential was however not significantly affected by protein concentration and ranged from -35.3 to -39.2 mV. The emulsions prepared were also heat treated at 60-90oC for 30 minutes. No sign of instability with a significant change in the size of emulsions due to heat treatment was observed from all emulsion samples prepared at different EWP concentrations (0.1 - 2%). However, phase separation of the emulsions was observed upon freezing at -20oC and thawing at 4 and 20oC, respectively, at all protein concentrations used. Also, the stability of emulsions was affected by the addition of salts, such as CaCl2 (5-100 mM) and NaCl (50-600 mM), with an increase in droplet size and phase separation. However, the emulsions were relatively more stable to salt-induced flocculation, especially against NaCl, at higher protein concentration (1-2%) than lower protein concentrations (0.1-0.8%). Lastly, the effect of pH 2-10 was also determined from the emulsions prepared at 1% EWP and 5% oil. Extensive droplet aggregation was observed at pH 4 and 5 as expected which is around the pI of most egg white proteins. On the other hand, it was not observed at extremely acidic pH 2.0 and alkaline pH 9-10 and in the control emulsion prepared at pH 8.3. In another part of the study, the effects of enzyme type (bromelain, ficin and papain), enzyme concentration (0.3, 0.5, 1, 2 and 4% w/w; enzyme/substrate (E/S) ratio) and hydrolysis time (0, 30, 60 and 120 minutes) on the degree of hydrolysis (DH) of EWP were investigated by diluting EWL containing 10% EWP to different EWP concentrations followed by adding enzymes into the EWL solutions. DH was observed to increase significantly (p < 0.05) with increasing enzyme concentration and hydrolysis time. A significant difference (p < 0.05) among the different types of enzymes was only observed from the samples with 4% E/S ratio at 120 minutes of hydrolysis time. Papain yielded the highest DH of 7.69% while bromelain and ficin yielded similar DH levels of 5.03% and 4.99%, respectively. The results of SDS-PAGE revealed that the protein bands corresponding to ovalbumin and ovotransferrin disappeared due to their enzymatic hydrolysis into smaller peptides but it was not significantly different between the samples treated with different E/S ratios and hydrolysis reaction times. The effects of enzyme concentration, DH and hydrolysis time on the emulsifying properties of hydrolysed EWP prepared with bromelain and ficin were investigated. Surprisingly, enzymatic hydrolysis significantly improved the appearance of emulsions prepared with EWL containing hydrolysed EWP by producing an emulsion free of aggregates compared to the control emulsions prepared from original EWP which had lots of large aggregates in it. For example, emulsions containing 10% oil and various EWP concentrations (1, 5 and 10%) prepared with hydrolysed EWP (4% E/S, DH 5.16%) yielded smaller droplet size (0.66-0.98 μm) than those of original EWP emulsions (1.22-39.35 μm). However, phase separation occurred immediately after preparation at all protein concentrations (1, 5 and 10%) used while phase separation occurred in only emulsions stabilised with 5 and 10% original EWP. When the emulsions were heat treated at 60-90oC for 0-30 minutes, gelation occurred in the emulsions prepared with 5 and 10% EWP concentrations while the emulsions prepared with 1% EWP had no gelation but had aggregation and phase separation after heat treatment. Emulsions prepared with 1% E/S ficin (DH 4.03% and 4.96%, respectively, after 2 and 4 hours of hydrolysis time) yielded smaller droplets size (0.75-0.87 μm) than droplet size (6.40-7.37 μm) of emulsions prepared with 1% E/S bromelain (DH 4.10% and 4.87% after 2 and 4 hours of hydrolysis time). Droplet size decreased as hydrolysis time increased from 2 to 4 hours for both ficin and bromelain hydrolysates with phase separation occurring the following day after the preparation of emulsions. Thus, DH and enzyme type had some influence on the emulsifying properties of EWP hydrolysates. In conclusion, this study demonstrated that egg white emulsions can be prepared with little or no aggregates using low oil (≤5%) and low protein (1%) concentrations and by enzymatic hydrolysis of EWP. Emulsions containing 5% oil prepared with a relatively higher protein concentration (1-2%) were more stable to destabilization to ionic strength (salt concentration), especially against NaCl. These could lead to production of egg white protein based-emulsions with distinct appearance and characteristics.
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    Power systems for dairy sheds : an investigation into the right mix of energy efficiency, load shifting and energy supply technologies : submitted as partial fulfilment of a Masters of Technology endorsed in Energy Management
    (Massey University, 2017) Marshall-Tate, Hugh
    This study investigated the potential for using stand-alone power systems for dairy milking sheds in New Zealand. The study was in two parts:  designing a typical load profile for a dairy shed and evaluating changes that could be made to the dairy shed to improve energy efficiency or shift load, using a mechanistic modelling approach.  using the optimisation modelling tool HOMER Pro to find the best configuration of power system, energy efficiency and/or load shifting improvements of a solar-diesel hybrid power system and a solar-diesel-biogas hybrid power system. The study found that milk vat insulation, variable speed drives and generator heat recovery were good investments to reduce power system costs. The high capital cost of ice banks made them less attractive for herds less than 370 cows. Superheat heat pumps and biogas systems were poor investments and increased costs in most cases when compared with the base scenario. While there was variation within the regions, overall the optimal system, when sensitivity scenarios were accounted for, was found to be similar between the three regions studied with the Bay of Plenty having the lowest overall costs followed by Taranaki and Manawatu. Sensitivity scenarios showed bias against deferrable loads such as ice bank refrigeration systems, hot water storage systems and the pumping of effluent. Diesel prices had a greater effect where the renewable fraction was low. Increasing diesel prices resulted in larger PV arrays and batteries.
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    Environmental evaluation of energy efficiency refurbishment in New Zealand's commercial office buildings : a thesis presented in partial fulfilment of the requirements for the degree of Doctor of Philosophy in Science in Life Cycle Management at Massey University, Manawatū, New Zealand
    (Massey University, 2017) Ghose, Agneta
    In New Zealand, 80 % of existing commercial office buildings are more than 20 years old and consume approximately 40 % more energy than newer counterparts. Moreover, nearly 38 % of the energy-related emissions in New Zealand’s cities are due to the heating and cooling requirements of commercial office buildings. Therefore, energy efficiency measures in office buildings are recommended to reduce operational energy related costs, provide better working conditions, and enhance business value. An energy efficiency refurbishment which involves adoption of multiple energy saving measures such as thermal insulation, improved glazing, air conditioning and lighting systems, can reduce the energy consumption of existing buildings by nearly 60 %. However, such a refurbishment also involves substantial construction work associated with the demolition and replacement of several building components, and this is associated with additional environmental impacts. It is therefore important to evaluate if the environmental benefits associated with reductions in energy demand can outweigh the environmental impacts of refurbishment. This research investigated the comprehensive environmental impacts of energy efficiency refurbishments in New Zealand’s office buildings using Life Cycle Assessment (LCA). The research used existing data collected for Building Energy End-use Study (BEES) by the Building Research Association of New Zealand (BRANZ). In particular, this research used the information on building design and annual energy consumption of existing and refurbished building prototypes. These building prototypes provided - construction details adopted in buildings of different sizes; and the operational energy performance based on typical climatic conditions found in New Zealand. The environmental performance of the buildings was calculated for Global Warming Potential (GWP), Ozone Depletion Potential (ODP), Photo-chemical Oxidation Potential (PCOP), Acidification Potential (AP), Eutrophication Potential (EP), Abiotic Depletion of resources (ADr), Abiotic Depletion of fossil fuels (ADff), Human toxicity carcinogenic (HT-carc), Human toxicity non-carcinogenic (HT-non carc), Eco-toxicity freshwater (ETfreshwater), Particulate Matter Formation (PMF), and Ionizing Radiation (IR). A series of studies were performed to: (i) assess the environmental impacts and identify the environmental hot-spots of energy efficiency refurbishment, (ii) assess the influence of building’s service life, energy, resource and waste management on the environmental performance of energy efficiency refurbishment, (iii) assess the influence of building size, design and location on the environmental performance of energy efficiency refurbishment, and (iv) to evaluate the contribution of energy efficiency refurbishment to New Zealand’s 2050 climate change mitigation target compared to the environmental performance of existing office building stock. The results showed that at energy efficiency refurbishments can reduce emissions for environmental impact categories affected by energy demand particularly for global warming, acidification and photochemical oxidation. However, the refurbishment is also associated with increase in environmental impacts affected by resource demand such ozone depletion potential, abiotic depletion of resources, human toxicity (carcinogenic) and ionizing radiation. Service life of over 25 years is required to compensate the embodied environmental impacts of refurbishment for most of the impact categories, particularly if the electricity is sourced from renewable energy sources. Refurbished components such as- on-site photovoltaic (PV), aluminium framed windows, façade components and heat pumps were identified as the major environmental hot-spots for most impact categories. The embodied environmental impacts to most categories could be reduced by 20 - 40 % if the waste recovery and recycling at construction site is improved. However, the overall environmental impacts of refurbished office buildings are highly sensitive to the choice of energy supply. Energy supply from grid electricity generated from renewable resources should be prioritised over the use of on- site PV. Benefits from on-site PV is limited if the grid electricity supply is mainly from renewable sources; moreover, the production of photovoltaic panels is energy and resource intensive. It can increase nearly 50 - 100 % of the embodied environmental associated with building refurbishment. If on- site photovoltaic is installed, it should be prioritised in buildings with large roof area located in regions with long sunshine hours. The results also show that in large buildings- efficient heating, ventilation and lighting equipment; and smaller wall to window ratios should be prioritised to reduce environmental impacts. In small buildings, the choice of façade materials with low embodied impacts should be prioritised to reduce environmental impacts. With respect to New Zealand’s 2050 target for the existing office building sector 60 - 90 % greenhouse gas emissions reductions is possible only if the office building stock refurbishment is combined with a renewable energy supply. Nearly 60 – 70 % of the greenhouse gas emissions can be reduced if the refurbishment of the existing office building stock is limited to existing large office building stock (>3500 m2) or to buildings in Auckland and Wellington. The main conclusions based on the results of this research are to prioritise better resource and waste management, to prioritise strategies for maintenance of refurbished buildings to promote longer service life, to support national level policies on increased use of renewable sources for grid electricity generation, and to prioritise refurbishment for a share of the building stock based on size and location which contributes to maximum energy reduction and minimal environmental impacts. The outcomes of this research can support national policy makers and independent building stakeholders (e.g. architects, owners, and engineers) who are keen on promoting energy efficiency refurbishments in New Zealand’s office buildings.
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    UV radiation as a new tool to control microalgal bio-product yield and quality : a thesis presented in partial fulfilment of the requirements for the degree of Doctor of Philosophy in Industrial Biotechnology at Massey University, Palmerston North, New Zealand
    (Massey University, 2018) Schaap, Roland
    While ultraviolet (UV) radiation is most commonly known as an abiotic stress, various studies have shown targeted UV exposure increases bioproduct and biomass yields in microalgae. Microalgal cultivation processes face significant limitations in achievable bioproduct and biomass yields and thus improvements offered by targeted UV treatments during large-scale microalgae cultivation provide an opportunity for development of a novel UV treatment tool. Growing demand in microalgae (bio)products indicate there may be a substantial market for such UV treatment tools. No initiatives that explore the development of targeted UV treatments during large-scale microalgae cultivation have been found in the literature or in the industry. In collaboration with industrial partner BioLumic, a company specializing in applying targeted UV treatments in plants as a tool in agriculture, this PhD research examined if specific treatments of UV radiation (i.e. specific in UV waveband, irradiance and exposure duration) can reliably increase carotenoid accumulation in the microalga Dunaliella salina and if this new understanding can be feasibly used to develop an industrial system for UV treatment of microalgae. The PhD research was conducted utilizing D.salina after evaluation in four commercially relevant microalgae species: Arthrospira platensis, Chlorella vulgaris, Haematococcus pluvialis and D.salina. A UV-A induced carotenoid accumulated response was identified in D.salina (strain UTEX 1644). Targeted UV-A treatments reliably induced carotenoid accumulation in this species, and the magnitude of the response depended on the UV-A wavelength, UV irradiance, UV exposure duration, and UV dose. The UV-A carotenoid accumulation response was induced within 6 hours and was largely complete in 96 hours (24 h·d⁻¹ UV exposure). The highest UV-A dose tested induced the highest carotenoid accumulation rates and the highest total carotenoid concentrations after continuous UV exposure (24 h·d⁻¹) at the highest UV-A irradiance tested (30 W·m⁻²). Total carotenoid concentration increases of up to 162% were thus observed after 72 hr of UV-A exposure. UV-A exposure was associated with slowed or stopped cell proliferation as well as increased D.salina cell size (up to 15%) and altered intracellular structural organization. Carotenoid accumulation ceased and cell proliferation increased when UV-A exposure was stopped, leading to a subsequent resumption of cell proliferation. UV-A induced carotenoid accumulation was improved 51% during UV-A exposure concomitant with non-UV carotegenic stimuli (high PAR intensity and salinity) compared to UV-A exposure alone. The observations from experiments carried out in the thesis served as inputs in a techno-economic analysis (TEA) model developed to assess feasibility of large-scale UV treatment. The TEA model was developed to allow assessment of the most critical areas for improving profitability of large-scale UV treatment technology, rather than provide absolute economical outputs for revenue and profit. The TEA was based on two reference cultivation systems currently used for commercial D.salina cultivation. The TEA analysis considered four locations for the UV treatment system applied along the cultivation process: pre-cultivation stage (i.e. inoculum), main cultivation stage, post-cultivation stage (i.e. immediately prior to harvest) and during fluid transfer between stages. A dedicated post-cultivation UV treatment stage was shown to have a number of advantages over other treatment options. A model cultivation system for the case-study of D.salina was developed assuming an annual β-carotene production of 1,000 kg. The developed TEA model cultivation system and TEA UV treatment system were able to identify a potential increase in profitability generated from the application targeted UV treatment during large-scale D.salina cultivation. The maximum increase in profitability was achieved using a broad wavelength UV treatment system (irradiance = 30 W·m⁻², exposure duration = 24 h·d⁻¹, surface area coverage = 100%) applied during an intensive cultivation post-cultivation system. A relatively small contribution of the UV treatment system to CAPEX and OPEX to overall β-carotene production cost (i.e. < 10%) combined with the large increase in β-carotene production (711 kg·y⁻¹ and 895 kg·y⁻¹ for fluorescent UV tube and UV LED systems, respectively) leads to potentially large increases in profitability. The TEA analysis identified the magnitude of the UV-A induced carotenoid accumulation response to be the most important factor to influence the potential profitability. Moreover, the TEA indicated the increases in profitability are strongly influenced by optical efficiency, electrical efficiency and maximum optical power. The profitability estimates from the current TEA indicate that UV treatment during commercial microalgae cultivation has potential and justifies further research. To our knowledge the exploration of the fundamental UV photobiology in microalgae required to develop UV treatment regimes from discrete UV wavebands, complemented with a commercial microalgal-engineering insight, to produce UV treatment regimes and UV treatment technology for application during large-scale microalgae cultivation, has never been attempted. The multidisciplinary approach employed during this PhD research explored for the first time the development of a UV treatment system from laboratory observations to commercial cultivation. The current research described for the first time the UV exposure behaviour of D.salina (strain UTEX 1644) to varying UV waveband, UV irradiance, UV exposure durations as well as UV response interaction with PAR and salinity. The case-study of UV treatment during large-scale D.salina cultivation in this PhD research allowed recommendations to be made to the industrial partner BioLumic on potential areas of focus for continued research and development.
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    Building development cost drivers in the New Zealand construction industry : a multilevel analysis of the causal relationships : a thesis submitted in fulfilment of the requirements for the degree of Doctor of Philosophy (PhD) in Construction, School of Engineering & Advanced Technology, Massey University, Albany, New Zealand
    (Massey University, 2018) Zhao, Linlin
    Building development cost is influenced by a raft of complex factors which range from project characteristics to the operating environment and external dynamics. It is not yet clearly understood how these factors interact with each other and individually to influence building cost. This gap in knowledge has resulted in inaccuracies in estimates, improper cost management and control, and poor project cost performance. This study aims to bridge the knowledge gap by developing and validating a multilevel model of the key drivers of building development cost (BDC) and their causal relationships. Based on literature insights and feedback from a survey of industry practitioners, some hypotheses were put forward in regards to the causal relationships between the BDC and the following key drivers as latent constructs: project component costs factor, project characteristics factor, project stakeholders’ influences factor, property market and construction industry factor, statutory and regulatory factor, national and global dynamics, and socio-economic factor. Observed indicators of the model's latent constructs were identified and measured using a mixed methods research design. Results showed that property market and construction industry factor was the most significant predictor of building development cost in New Zealand, while project component cost factor has the least impact. The model’s fit to the empirical dataset, and its predictive reliability, was validated using structural equation modelling. Results of an additional model validation test by a panel of experts further confirmed its efficacy. Overall, the results suggest that sole reliance on the immediate project component costs without due consideration of the wider and more influencing effects of the external factors could result in inaccurate estimates of building development cost. Key recommendations included addressing the priority observed indicators of the most significant latent variables in cost studies and analysis. Keywords: Building development cost, cost drivers, cost modelling, cost prediction
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    CMOS radiation sensor design in 130nm CMOS technology : a thesis presented in partial fulfillment of the requirements for the degree of Master of Engineering in Electronics and Computer Engineering at School of Engineering and Advanced Technology, Massey University, Albany Campus
    (Massey University, 2017) Zhang, Chaoping
    This research work deals with a CMOS radiation sensor design, which covers a new open source floating-gate MOSFET (FGMOSFET) device model for analog circuit design, Floating Gate Radiation Field Effect Transistor (FGRADFET) design, FGRADFET sensor output circuit design and their layout implementation using the 130nm IBM CMOS process. At first, a new FGMOSFET device model to facilitate circuit design is presented. In this model, the floating gate is charged by the Fowler-Nordheim tunneling effect. The equations representing the new device model were explored and verified on MATLAB. Verilog-A script was employed to transfer the equations and build the complete device model. The new FGMOSFET circuit model was plugged-in as a pop-up menu component in a standard 130 nm CMOS technology design library so that it can be instanced directly on a schematic editor palette for analog circuit simulation and design in a similar fashion as the standard MOSFET devices. Furthermore, the thesis describes the radiation sensor of FGRADFET that has an extra silicon area (125μm×200μm) as an antenna to sense the radiation from the environment. There are 16 PMOS transistors (1μm×2μm each) beneath the edge of the antenna to charge the floating gate. A radiation sensor readout circuit is also designed for this sensor. This circuit includes differentiator, pre-amplify buffer, chopper amplifier, low-pass filter and single-ended output amplifier. This integrated dosimeter has a 3.205mW power consumption and 2.33mGy- 23mGy measuring range (The single-ended output voltage changes from 26mV to 967mV), which could be used for tremendous radiation exposure applications such as radiation therapy.
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    Behaviour of milk protein ingredients and emulsions stabilised by milk protein ingredients in the simulated gastrointestinal tract : a thesis presented in partial fulfilment of the requirements for the degree of Master of Food Technology, Massey University, Manawatu, New Zealand
    (Massey University, 2017) Wang, Xin
    Milk clotting behaviours in the stomach impact the digestion rates of protein and fat. A variety of milk protein products are applied as functional ingredients in many foods. This research was conducted to investigate the digestion behaviours of various commercial dairy ingredients and lipids in emulsions stabilised by these ingredients using a dynamic in vitro digestion model, i.e., a human gastric simulator (HGS), with a focus on the effect of different structures of clots formed in dairy ingredients during gastric digestion on hydrolysis of proteins and/or lipids. Skim milk powder (SMP), milk protein concentrate (MPC) 4851, MPC 4861, sodium caseinate, whey protein isolate (WPI) and heated (90°C, 20 min) WPI were used in the present study. Results showed that SMP and MPC 4851, which contained casein micelles, formed ball-like clots with a relatively dense network after 10 min of gastric digestion. These clots did not disintegrate after 220 min of digestion. MPC 4861 and sodium caseinate generated clots at around 40 min, and a loose, fragmented structure was observed at the end of the gastric digestion due to a lacking micellar structure of caseins. No clot was observed in WPI or heated WPI after 220 min gastric digestion, although aggregation occurred at around 40 min in heated WPI. These differences in coagulation behaviours apparently affected the rate of gastric emptying and protein hydrolysis by pepsin in the gastric system. In SMP and MPC 4851, the gastric emptying and hydrolysis of caseins was much slower than that observed in MPC 4861 and sodium caseinate. The most rapid gastric emptying of proteins was observed in the WPI samples both with and without heating. This is attributed to the formation of varied structured clots at different times under the gastric conditions. The effect of protein concentration on the gastric behaviour of these dairy ingredients in solution was then examined, with a particular emphasis on the structure of clots. SMP and MPC 4851 have been selected as model protein ingredients. Their gastric behaviours were investigated over a protein concentration range of 0.5-5.0% (w/w). The results showed that the digestion behaviour of SMP and MPC 4851 followed a similar pattern. The rate of pH changes in the emptied digesta during digestion was protein concentration dependent. With an increase in protein concentration, the decrease in pH slowed. The protein concentration had no apparent impact on the casein clotting time. Clots were formed in the first 10 min of digestion in all samples. However, in both SMP and MPC 4851, when protein concentration was lower than 2.0% (w/w) the clots consisted of small protein pieces with a loose, porous and open structure after a 220 min digestion. Whereas a cheese ball-like clot with a denser network was observed at the end of gastric digestion when the protein concentration varied from 2.0% to 5.0% (w/w). Such a difference in the structure apparently affected the rate of protein hydrolysis. A more rapid hydrolysis (P < 0.05) of the clotted protein was observed when protein concentration was lower than 2.0% (w/w) compared to the samples containing a higher proportion of protein (2.0%-5.0%, w/w). To study the effect of different coagulation behaviours on the digestion of oil droplets in oil-in-water emulsions, these dairy ingredients (with the exception of SMP) were used to prepare an oil-in-water emulsion (20.0% soy oil and 4.0% protein, w/w). They were digested under the dynamic gastric conditions using the HGS. The gastric digesta was emptied at 20 min intervals. Then all digesta were mixed to investigate the lipid digestion under the small intestinal conditions. Changes in physicochemical properties of emulsions, involving the particle size, the microstructure, the oil content of the emptied gastric digesta and the amount of free fatty acids (FFAs) released during the small intestine stage, were determined using an in vitro small intestinal digestion model. Aggregation of MPC 4851-stabilised emulsion took place after 5 min of digestion in the HGS with the largest size. The aggregates remained in the stomach and did not disappear during the whole gastric digestion. The hydrolysis of the aggregated network by pepsin was largely slowed by the reduced ability of the simulated gastric fluid (SGF, containing pepsin) to diffuse into the larger sized aggregates. MPC 4851-stabilised emulsion thus resulted in the slowest release of oil droplets into the small intestine. In comparison, MPC 4861 and sodium caseinate-stabilised emulsions aggregated in the stomach at approximately 40 min, forming smaller sized aggregates. These aggregates disintegrated at the mid and late-stages of digestion in these two emulsions. Therefore, MPC 4861 and sodium caseinate-stabilised emulsions had a more rapid delivery of oil droplets into the small intestine. In relation to the WPI-stabilised emulsions both with and without heating, the aggregations formed at a similar time to that which was observed in MPC 4861 and sodium caseinate-stabilised-emulsions; i.e., at approximately 40 min. However, they had the smallest sized aggregates amongst all samples and they disintegrated quickly with further digestion. WPI-stabilised emulsions both with and without heating had the fastest gastric emptying and hydrolysis by pepsin in the early and mid-stages of the gastric digestion process. Thus, the highest level of oil content contained in the emptied gastric digesta was produced from both WPI-stabilised emulsions. In the mixed gastric digesta, which were subjected to the small intestinal digestion, the oil contents contained in the different emulsion samples varied. This difference impacted the extent of lipid digestion by pancreatic lipase. The sample with a higher oil content released a greater amount of FFAs compared to the sample with a lower oil content. The extent of lipid digestion of different emulsion samples adhered to the following pattern: MPC 4851-stabilised emulsion < MPC 4861-stabilised emulsion < sodium caseinate-stabilised emulsion, WPI-stabilised emulsions both with and without heating. Overall, the gastric behaviours of dairy ingredients either in solutions or emulsions were affected by the formation of structured clots/aggregates. The differences in clotting/aggregation times and their structures were greatly dependent on the component and structure of protein, the processing prior to digestion and the susceptibility to proteases. These differences in protein coagulation/aggregation behaviour impacted the rates of protein hydrolysis and gastric emptying. The oil content and protein composition of the gastric digesta transferred into small intestine and the extent of lipid digestion in small intestine were also affected. These results are important in an application perspective. They provide useful information for the design and development of healthier food products by allowing greater control over the manipulation of protein bioavailability, which subsequently provides greater control over lipid metabolism.