Modelling the production of biodiesel from non-edible oils (Jatropha curcas oil and Tobacco seed oil (TSO): a kinetic study

Thesis submitted in partial fulfilment of the requirements for the degree of Master of Science in Engineering at the School of Chemical and Metallurgical Engineering, Faculty of Engineering and the Built Environment, University of the Witwatersrand Johannesburg, South Africa October, 2017The significant increase in the primary energy demand and the effort to reduce harmful emissions related to the greenhouse gases enhanced the search for alternative energy. Production and modelling processes of biofuel from non-edible oil sources assist in the process development of an environmentally friendly fuel such as biodiesel. This work focused on the kinetic modelling of biodiesel synthesised from non-edible oils. Two types of non-edible oils (Jatropha curcas seed oil and Tobacco seed oil) were used in this study including the development of the kinetic behaviour of the transesterification reaction. A linear polynomial model was generated from experimental data found in literature in order to study the influence of operating parameters during biodiesel production. It was found that the temperature improves the yield of biodiesel; this is attributed to the fact that temperature affects the reaction rate constants; and the higher the reaction rate, the lower the activation energy required for a reaction to occur. The optimum conditions for the transesterification of Jatropha curcas seed oil are a temperature of 55 0C, methanol to oil ratio of 6:1, catalyst concentration of 1.2% KOH (by volume of oil), and agitation speed range of 0-250 rpm. Results from both the homogeneous and heterogeneous reactions of Jatropha curcas oil and tobacco seed oil were used to verify the theoretical kinetic and empirical models. It was found that both models describe the kinetic behaviour of transesterification with minor deviations in the estimated parameters. However, the use of empirical model in determining the reaction order, as opposed to the theoretical assumption, gave a second order with respect to oil triglycerides at a temperature of 60 0C. The theoretical kinetic model gave a first order with respect to oil triglycerides. In this case, the activation energy was found to be 71.83 kJ/mol and pre-exponential factor was found to be 2.48 x1010. More investigation should be done to describe the kinetic behaviour of biodiesel production from non-edible oil in order to confirm the correct reaction order and why there is change in reaction order when the temperature increases above 60°C.MT201

Airborne Contaminant Dispersal in Critical Built Environments

The Indoor Air Quality (IAQ), being one of the most significant exposures to human beings, encompasses the concepts of comfort and safety from unwanted contaminants. Whereas the thermal comfort is controlled through proper conditioning and distribution of ventilated air, controlling the airborne contaminants requires careful investigation of the flow characteristics. IAQ translates to different requirements, depending on the intended use of the indoor environment. In critical indoor spaces such as Operating Rooms and Cleanrooms, the principal focus of IAQ is to remove/contain/divert contaminants flowing with the airstream to maintain the required sterility, as contamination can lead to adverse patient/product outcomes. The airborne contaminants, generally submicron-sized particles, are controlled by directional airflow through differential pressure, depending on whether the space needs to exfiltrate (e.g., Operating Room – positive pressure) or contain (e.g., Isolation Room – negative pressure) the airborne contaminants. The current design paradigm that determines such pressure differential assumes steady-state conditions. Theoretically, during the steady-state, the rate of flow velocity change is zero, resulting in a constant flow field in time, and the distribution of contaminants in the space can be modeled using ordinary differential equations. Therefore, the steady-state assumption must hold to explain the contamination dispersal. However, in practice, transient occupant interventions like a door opening and walking through the steady-state flow fields alter the flow characteristics. In response, this dissertation examines how occupant-introduced transient events affect the steady-state flow. This study aims to quantify and identify patterns of the changes in the flow characteristics for different scenarios of realistic door openings and human walks under a range of ventilation rates through controlled experiments and numerical simulations. Through specifically designed experiments, the impacts of door operation and occupant walking were characterized and quantified based on different levels of supply flow rates from the ventilation system. The results of the experiments suggested that special considerations were required to control for the transient phenomena and the pressure differential. The walking and door opening experiments also found distinguishable changes in the flow characteristics under each separate interaction between the indoor environment and the occupant. It was interesting to note that even though the magnitude of the effects was different for different levels of initial condition and intervention types, the changes in the flow properties exhibited identical patterns that were possible to model and make predictions. Thus, this dissertation considers the sporadic transient interventions from the occupants (e.g., - door opening and walking) as events and discusses an approximation method called ‘Event-Based Modeling’ (EBM) using the collected data through these experiments. Two-dimensional numerical models were developed to obtain additional data on the changes in airflow characteristics and were used to model and test the accuracy of EBM’s prediction capabilities. The results demonstrated that the predictions from EBM were accurate, and the computational efficiency is improved compared to the traditional numerical simulation approach. This method can eliminate parallel modeling of the same phenomena, providing alternatives to simulate complex and computationally intensive transient events repeatedly. As a potential application, the changes in flow velocities from human-environment interactions in a critical indoor environment like an operating room can be predicted using the EBM method. This way, the ventilation systems can be designed as occupant-centric and energy-efficient by considering the impacts of the transient events instead of only considering the steady-state events

Optimising digital nature for wellbeing

The global burdens of negative psychological states such as stress, anxiety, and burnout represent a growing public health concern. As the incidence of these conditions has risen so too has awareness that natural environments might provide cognitive and affective benefits. Yet unrelenting urbanisation, unprecedented species extinction, and rampant ecological degradation are fostering a creeping extinction of experience, straining the links between people and planet. In an increasingly technologically mediated world, growing emphasis is being placed on how digital forms of nature could impact health. Understanding how simulated contact with the natural world might be optimised for positive wellbeing outcomes is vital if ‘virtual nature’ is to be used as a therapeutic tool. This thesis consists of three original studies – conducted with large samples and as part of national broadcast initiatives – that aimed to address this burgeoning need. We first investigated nuances in the way natural soundscapes are experienced. Through an award-winning collaboration with the BBC Natural History Unit, a novel podcast series and experiment generated responses from 7,596 participants. Results indicated how the composition of nature-based soundscapes can affect their restorative potential, demonstrated the crucial role that memories play in these relationships, and suggested that appraisals of restoration can exert an important mediating effect on pro-environmental behaviour. Next, a similar level of granularity was applied to landscape aesthetics. An online experiment probed how ephemeral features such as sunrise, sunsets, and storms can impact appraisals of virtual environments. Data from 2,509 people supported the familiar urban-nature dichotomy yet revealed substantial momentary and diurnal heterogeneity in measures of beauty and awe. Changes in these metrics also partially mediated participants’ willingness to pay to visit these locations in the ‘real world’. Partnering again with the BBC on a multi-platform broadcast initiative called Soundscapes for Wellbeing, our third experiment assessed how the visual and acoustic elements of a digital nature experience, including music, might influence viewer emotions. Analyses from 7,636 respondents suggested that whilst music could enhance high arousal feelings such as excitement, natural sounds were integral to eliciting restoration, calmness, awe, and nostalgia. Again, these data revealed a substantial moderating effect of memories, underlining the importance of lived experiences in determining outcomes. Taken together, these findings reveal important distinctions in the way natural soundscapes are perceived, demonstrate the potential for both ephemeral features and natural sounds to elicit the complex emotions of awe and nostalgia, and highlight the profound moderating effects of personal memories. Future work might focus on expanding understanding of how awe, nostalgia, and memories could represent a hitherto under-recognised depth to the therapeutic potential of encounters with nature in both virtual and real settings.Wellcome Trus

The challenges facing recruitment and retention of doctors in obstetrics and gynaecology in Ireland

Obstetrics and gynaecology is a medical specialty which includes all aspects of sexual and reproductive health across the life course of a female. It is traditionally perceived as a “lifestyle unfriendly” specialty, and future specialist shortages have been identified internationally. Irish maternity services have low consultant numbers, understaffed units, predominantly female trainees and have been exposed to high levels of litigation and intense media scrutiny for years. Using a combination of quantitative and qualitative research, this thesis presents a detailed exploration of attitudes to and experience of obstetrics and gynaecology as a career from the perspectives of the following groups: 1. Medical students from an Irish medical school (University College Cork), 2. Current specialists in training across all levels of experience, and 3. Consultant obstetrician gynaecologists. The quantitative research involved detailed surveys of all penultimate year medical students in UCC (n=134, response rate 68.7%) and trainees in obstetrics and gynaecology (n=124, response rate 70.8%). The qualitative research involved semistructured interviews using deductive thematic analysis, of 17 consultant obstetrician gynaecologists from different ages, genders and geographical locations across the country. For medical students, factors that increased the attraction to the specialty were continuity of care (p= 0.002), delivering babies (p=0.004), female patients only (p=0.026), limited focus of disease (p=0.01), intellectual content (p=0.001), combination of obstetrics and gynaecology (p=0.014), predominance of female practitioners (p=0.002), career opportunities and interaction with consultants (p=0.016). Protection from litigation was deemed by 85% of students to moderately or strongly increase the appeal to the specialty. When trainees were asked how much they enjoyed working in the specialty on a scale of 1 to 10 with 1 representing no enjoyment at all and 10 representing immense enjoyment, 85.3% responded with a value of 7 or higher. When asked if they would recommend a career in obstetrics and gynaecology to their family member or child, only 3% strongly agreed. 86.7% of trainees felt that the media did not have a positive impact on patients and 94.1% felt that the media representation of obstetrics and gynaecology was fair and balanced. 82.3% felt that the media negatively influenced patients’ attitudes to doctors. 37.1% of trainees have been involved in a medico-legal case and 79.5% state that the medico-legal climate has a moderately or strongly negative impact on recruitment and retention, while 84.2% feel it has a moderately or strongly negative impact on patients. In terms of future workforce planning, female trainees are significantly more likely to consider job-sharing (p=0.006) and are less likely to do private practice in obstetrics and gynaecology (p=0.002). 50.4% of all trainees plan to take parental leave and 33.9% plan on taking a sabbatical. The qualitative part of the study reflected themes of gender imbalance, reduced experience of new consultants due to EWTD, increased patient demand and unrealistic expectation, harm due to negative media coverage and the litigation culture, new entrant consultant pay disparity and lack of advocacy for doctors from professional bodies and the Health Service Executive. Solutions to the problems raised included restoration of pay parity, increased consultant numbers, improved advocacy, formal mentorship, and tackling negative media coverage and the litigation culture. Robust workforce planning, flexibility in training and consultant posts, diversification of the specialty to include community gynaecology and interdisciplinary spread of clinical care were also recommended. The voice of the current and future physician was at the centre of this work and the opinions and perceptions of these doctors is what I wish to address in this thesis. Their knowledge of the particular problems facing obstetrics and gynaecology in terms of clinical need and medical recruitment is unparalleled. Policymakers would do well to partner with the professional and training bodies to ensure, practical, economical and evidence-based solutions to the problems facing recruitment and retention in maternity services

Psychological Engagement in Choice and Judgment Under Risk and Uncertainty

Theories of choice and judgment assume that agents behave rationally, choose the higher expected value option, and evaluate the choice consistently (Expected Utility Theory, Von Neumann, & Morgenstern, 1947). However, researchers in decision-making showed that human behaviour is different in choice and judgement tasks (Slovic & Lichtenstein, 1968; 1971; 1973). In this research, we propose that psychological engagement and control deprivation predict behavioural inconsistencies and utilitarian performance with judgment and choice. Moreover, we explore the influences of engagement and control deprivation on agent’s behaviours, while manipulating content of utility (Kusev et al., 2011, Hertwig & Gigerenzer 1999, Tversky & Khaneman, 1996) and decision reward (Kusev et al, 2013, Shafir et al., 2002)