Dissertations / Theses on the topic 'MINIMIZE RISK'

The use of financial derivatives requires special expertise, experience and rigorous controls. Critical management system be in place commensurate with each institution's use of derivative products. derivatives should not be executed without the proper system and internal controls necessary to monitor and analyze the performance of the instruments. An institution needs to ensure that the rewards associated with derivatives are commensurate with the risk being taken and that these risks are understood by the board of directors and senior management. This does not mean simply enumerating an endless list of theoretical possibilities, but quantifying risks so that the trivial and the significant are appropriately considered. In order to do this, there must exist real incentives that come form quantifying risks, tying these measures to compensation and business unit evaluation, and proper accountability. It is imperative that management understand what they are attempting to accomplish in making use of the various derivative products in the marketplace. when used properly, derivative products can become effective tools in managing business risks. In the marketplace, derivatives can be used to expand product offering to customers, manage capital and funding costs, and alter the risk-reward profile of a particular item or an entire balance sheet. Most importantly, derivative transactions offer the opportunity for financial institutions to reduce risks in the marketplace. An optimal risk management process works more at getting relevant risks on the radar screen than measuring what already appears on the radar screen more precisely. Derivatives have become an integral part of the financial markets because they can serve several economic functions. The counterparty must be an investment grade credit and the agreement must be marked to market no less frequently than monthly.

The exposure of companies to turbulence, uncertainty, and vulnerability in their supply chain results in supply chain disruption with an estimate cost of $10 million for each supply chain disruption. The purpose of this case study was to explore the strategies supply chain managers use to mitigate supply chain disruption on business performance in a pharmaceutical company in Maryland. Contingency theory of fit formed the conceptual framework for this study. Participant perceptions were elicited in interviews with 11 supply chain managers regarding strategies to mitigate risks associated with supply chain disruptions. Data from interviews and supporting documents were processed and analyzed using data source triangulation to discern emergent themes. Three main themes emerged: (a) supply chain design, planning, and forecasting; (b) flexible and multiple supplier base; and (c) resource allocation and demand management. The implications for positive social change include the potential of reducing supply chain risk, which could lead to lower prices of products for consumers, increased stakeholder satisfaction, and a higher standard of living.

This study examined loneliness and future orientation as predictors of suicidal risk, namely, depressive symptoms and suicide ideation, in a sample of 228 college students (54 males and 174 females). Results of regression analyses indicated that loneliness was a significant predictor of both indices of suicidal risk. The inclusion of future orientation was found to significantly augment the prediction model of both depressive symptoms and suicide ideation, even after accounting for loneliness. Noteworthy, beyond loneliness and future orientation, the Loneliness × Future Orientation interaction term was found to further augment both prediction models of suicidal risk. Consistent with the notion that future orientation is an important buffer of suicidal risk, among lonely students, those with high future orientation, compared to low future orientation, were found to report significantly lower levels of depressive symptoms and suicide ideation. Some implications of the present findings for studying both risk and protective factors associated with suicidal risk in young adults are discussed.

Adolescence is a time of increased control over food choices and dietary practices. Participating in high school sports or attending college presents unique nutritional concerns and health risks. Some female high school athletes have low energy availability (consuming inadequate calories to compensate for exercise energy expenditure), which can result in menstrual dysfunction, bone loss, and injury, also known as the female athlete triad (Triad). College students who consume diets low in fruits and vegetables and high in fast food are at increased risk for weight gain, chronic disease, and some cancers. Nutrition education interventions that were tailored to the participants' unique nutritional concerns yielded positive results such as increased Triad knowledge among female high school athletes and increased self-efficacy and readiness to change dietary behaviors among college students. Peer-led education was preferred by college students, but not by high school students.

Master of Public Health
Public Health Interdepartmental Program
Kate KuKanich
The College of Veterinary Medicine (CVM) environment is a place where veterinarians, veterinary staff, and veterinary students may have increased risk of exposure to zoonotic pathogens. This exposure may occur in classrooms or laboratories where pre-clinical veterinary students and non-clinical staff frequent. Exposure may also occur in the veterinary teaching hospital (VTH) and may impact veterinary patients, clinicians, interns, residents, veterinary technicians, veterinary students, animal caretakers, and others. This thesis is divided into 3 chapters. The first chapter describes a current review of the literature involving risk of zoonotic pathogen exposure at VTHs including descriptions of the most commonly documented zoonotic pathogens and their transmission, environmental sources of zoonotic pathogens at VTHs, and ways to prevent zoonotic pathogen exposure at individual and institutional levels. The second chapter describes an original research study of hand hygiene behavior among pre-clinical veterinary students at a CVM. The purpose of this study was to determine if a campaign could improve hand hygiene among veterinary students at extracurricular meetings serving meals. Campaign interventions included a 3.5 minute educational video and a novel motivational poster. The video was presented to all 1st, 2nd, and 3rd year veterinary students. Posters encouraging hand sanitization were displayed on doors and tables alongside sanitizers at each meeting. Observational hand hygiene data were collected immediately after introduction of interventions and again 3 months later. Environmental sampling for presence of bacteria in and around meeting locations was also performed. Observed hand hygiene was lowest during baseline (11.0% +/- 1.7), improved significantly post-intervention (48.8% +/- 3.2), and remained improved at 3-month follow-up (33.5% +/-4.0). Females had higher probability of hand- sanitizing (35.9% ± 2.2) than males (21.4% ± 2.4) (p<0.01). Clostridium perfringens was isolated from 2/42 samples, and Salmonella spp. were isolated from 4/42 samples. This study documented that a short-term public health campaign targeting veterinary students successfully improved hand hygiene before meals. The final chapter discusses future areas of research in the realm of risk of zoonotic pathogen exposure and risk mitigation at CVMs.

Thesis (M.C.P.)--Massachusetts Institute of Technology, Dept. of Urban Studies and Planning, 2008.
Includes bibliographical references (p. 47-50).
Exploding growth along the Colorado Front Range has expanded the wildland-urban interface-the area where homes and vegetation mix. This area, known as the WUI, is at high risk of wildfires. Wildfire risk is based on both natural conditions, such as invasive species and climate change, and human development decisions that allow continued growth in fire-prone areas. This thesis examines the approaches to wildfire risk mitigation taken by six counties along the Front Range. I argue that these mitigation approaches are effective but do not tackle important aspects of the wildfire problem, including who pays and how risks continue to increase. Counties should minimize development in the WUI by adopting strong policies that incorporate the full costs of fire protection into local jurisdictional budgets and address growth management in the WUI. This requires a greater incorporation of the land-use planning process into decisions that put people and property at risk to wildfire.
by Molly Anne Mowery.
M.C.P.

Safety cases must be produced by offshore operators to assess the risks posed to the personnel by potential accidents. On an offshore platform two of the major hazards are fires and explosions resulting from an accidental hydrocarbon release. The overpressures generated during an explosion can threaten the integrity of the platform structure. It is therefore important to be able to estimate the overpressures generated, should an explosion occur, and to predict the frequency of such an event. A methodology has been developed to predict the frequency of explosions of different magnitudes occurring in a module on an offshore platform. This methodology combines established risk assessment techniques, such as event tree analysis and fault tree analysis, with fluid flow modelling. Assumptions have been made in the methodology to simplify the calculation procedure. These assumptions relate to the conditions under which the leak occurs, the build up of gas in air concentration and the probability calculations. Frequency predictions are required to be as accurate as possible to enable the acceptability of the risk to be determined and reduced to a level which is as low as reasonably practicable. Hence each of the assumptions within the methodology has been addressed, to determine a more complete prediction tool. Once an accurate frequency for the explosion occurring has been determined, the risk to personnel must be minimised to an acceptable yet practical level. On existing designs it is impractical to alter the layout of the platform. However the nature of the safety systems may be changed. These safety features include isolation, blowdown, mitigation and detection systems. An optimisation study presents three schemes to identify the optimum configuration of the safety systems, in terms of the overpressures generated, as a means of reducing the risk to the platform.

The transition process to ICT (Information and Communication Technology) has had significant influence on different aspects of society. Although the computerisation process has motivated the alignment of different technical and human factors with the expansion process, the technical pace of the transition surpasses the human adaptation to change. Much research on ICT development has shown that ICT security is essentially a political and a managerial act that must not disregard the importance of the relevant cultural characteristics of a society. Information sharing is a necessary action in society to exchange knowledge and to enable and facilitate communication. However, certain information should be shared only with selected parties or even kept private. Information sharing by humans forms the main obstacle to security measure undertaken by organisations to protect their assets. Moreover, certain cultural traits play a major role in thwarting information security measures. Arab culture of the United Arab Emirates is one of those cultures with strong collectivism featuring strong ties among individuals. Sharing sensitive information including passwords of online accounts can be found in some settings in some cultures, but with reason and generally on a small scale. However, this research includes a study on 3 main Gulf Cooperation Council (GCC) countries, namely, Saudi Arabia (KSA), United Arab Emirates (UAE) and Oman, showing that there is similar a significant level of sensitive information sharing among employees in the region. This is proven to highly contribute to compromising user digital authentication, eventually, putting users’ accounts at risk. The research continued by carrying out a comparison between the United Kingdom (UK) and the Gulf Cooperation Council (GCC) countries in terms of attitudes and behaviour towards information sharing. It was evident that there is a significant difference between GCC Arab culture and the UK culture in terms of information sharing. Respondents from the GCC countries were more inclined to share sensitive information with their families and friends than the UK respondents were. However, UK respondents still revealed behaviour in some contexts, which may lead potential threats to the authentication mechanism and consequently to other digital accounts that require a credential pass. It was shown that the lack of awareness and the cultural impact are the main issues for sensitive information sharing among family members and friends in the GCC. The research hence investigated channels and measures of reducing the prevalence of social engineering attacks, such as legislative measures, technological measures, and education and awareness. The found out that cultural change is necessary to remedy sensitive information sharing as a cultural trait. Education and awareness are perhaps the best defence to cultural change and should be designed effectively. Accordingly, the work critically analysed three national cybersecurity strategies of the United Kingdom (UK), the United States (U.S.) and Australia (AUS) in order to identify any information security awareness education designed to educate online users about the risk of sharing sensitive information including passwords. The analysis aimed to assess possible adoption of certain elements, if any, of these strategies by the UAE. The strategies discussed only user awareness to reduce information sharing. However, awareness in itself may not achieve the required result of reducing information sharing among family members and friends. Rather, computer users should be educated about the risks of such behaviour in order to realise and change. As a result, the research conducted an intervention study that proposed a UAE-focused strategy designed to promote information security education for the younger generation to mitigate the risk of sensitive information sharing. The results obtained from the intervention study of school children formed a basis for the information security education framework also proposed in this work.

The characteristics of a patient support interface can influence the susceptibility of subjects, particularly there who are immobilised and insensate, to pressure ulcer development. Accordingly, externally powered alternating pressure air mattresses (APAM) are utilised to produce intermittent pressure relief and control of the interface microclimate. These conditions will permit adequate blood and lymph flow within the soft tissues and favourable conditions at the loaded skin surface and thus minimise the risk of ulcer formation. Two sets of measurements were performed. Tissue viability was estimated, from a measure of transcutaneous gas tensions and sweat content, from healthy volunteers subjected to various alternating pressure regimens. The latter was achieved by two different strategies a) a custom–made controller which imposes the pressure profile on the subject and b) a prototype APAMs incorporating a novel sensor, which adjusts the profile according to individual subject characteristics. The latter prototype was placed on an articulated hospital bed, with an adjustable Head of Bed (HOB) angle. The second set of measurements involved monitoring the microclimate, namely temperature and humidity, at the interface loaded with a human analogue model supported on an APAM system. The interface was saturated with moisture to simulate sweating. The human studies, involving healthy subjects with BMI values ranging from 18.9 to 42.5 kg/m2, revealed significant differences in soft tissue response under various support surface profile by both strategies. In many cases, the TcPO2 levels either remained fairly stable during the loaded period or fluctuated at a periodicity equivalent to the cycle period of the APAM system, with the corresponding TcPCO2 levels remaining within the normal basal range. These findings were associated with II maximum interface pressures generally not exceeding 50 mmHg (6.67 kPa). By contrast in some cases, there was a significant compromise to the TcPO2 levels during the loaded period, which was often associated with an increase in TcPCO2 levels. These cases generally corresponded with the internal pressures in the mattress prescribed at a maximum amplitude of 100 / 0 mmHg or when the Head of Bed angle was raised to 45º or above. Changes in prototype covering sheet and air flow rates of the APAM system were found to influence both interface temperature and humidity. These results revealed enhanced levels of humidity often reaching 100% RH at the high simulated sweat rates. By contrast, at the lower sweat rate of 1.5 ml/min, the nature of the prototype covering sheets had an effect on the interface humidity profile, with values considerably reduced in the latter stages of the monitoring period. These results were compared with a compartmental model, which predicted the transport of moisture and heat using various mattress support systems. The results offer the potential for the development of intelligent APAM systems, whose characteristics can be adjusted to an individual morphology. These systems will need to be designed to ensure adequate tissue viability and maintain appropriate microclimate at the loaded interface. Such an approach will be directed at those subjects considered to be at high/medium risk of developing pressure ulcers.

The majority of software development projects, in particular the larger more complex ones, end in failure (The Standish group, 1994, 1998,2003,2009). There has been much discussion over the best approach to adopt in order to address this issue (Beck and Fowler, 2000; Boehm and Turner, 2003; Larman, 2004; Rico, 2008). Proponents of both Agile and Plan-Driven methods have put forward arguments supporting their particular preference. Agile software development methods such as Extreme Programming (XP), Scrum, Crystal, DSDM and Feature Driven Development (FDD) promise increased customer satisfaction, lower defect rates, faster development times, and a solution to rapidly changing requirements. Plan-driven approaches such as Waterfall, incremental, spiral, Rational Unified Process (RUP), the Personal Software Process (PSP), or methods based on the Capability Maturity Model (CMM), promise predictability, stability, and high assurance. However, both approaches have shortcomings that, if left unaddressed, can lead to project failure. One of the purposes of this study is based on Barry Boehm's (Boehm and Turner, 2003) risk-based framework of risk analysis by integrating each phase of the project life cycle with the risk process framework in an overall development strategy in order to convince the stakeholders what risk they should be aware of and getting their involvement in the early project risk assessment stage. This is an empirical survey-based study to identify the risk factors from the perspective of software practitioners who practice agile software development or/and plan-driven methods in software development projects. The study used a mixture of quantitative and qualitative methods. Based on the literature reviews, and an analysis of the key factors which caused IT project failures collected from the survey, this study proposes that the integrated risk analysis framework is an ideal tool of 6- Dimensional tool to define and address the risks associated with agile and plan-driven methods. The proposed framework also helps IT managers to manage risks and budgets for managing risks in order to make their projects successful.

Swimming pools contain organic compounds originating from both filling water and bather load. These organic compounds react with added disinfectants to form unwanted disinfection by-products in the pools. This Thesis presents an improved understanding of the occurrence and formation of disinfection by-products in pools and their potential chemical health risks. It provides significant knowledge for pool operators and the leisure industry to drive improvements in the chemical water quality of pools in the future.

Orientador: Elisabete Salay
Tese (doutorado) - Universidade Estadual de Campinas, Faculdade de Engenharia de Alimentos
Made available in DSpace on 2018-08-20T07:40:39Z (GMT). No. of bitstreams: 1 Danelon_MarianaSchievano_D.pdf: 3248029 bytes, checksum: e8ac5de57aff9a65e1d5662613e18c3d (MD5) Previous issue date: 2012
Resumo: O padrão alimentar da população brasileira tem sido caracterizado, entre outros aspectos, pelo reduzido consumo de hortaliças e pelo crescimento do número de refeições realizadas fora do domicílio. A utilização dos serviços de alimentação pode representar oportunidade para a inclusão de variedade de hortaliças na dieta. Tem sido pouco estudado, no Brasil, o comportamento do consumidor quando se alimenta fora de casa. Este pode ser influenciado pelos riscos percebidos em uma situação de compra. Com base na percepção dos riscos, o consumidor pode adotar diferentes estratégias no momento das escolhas, na tentativa de minimizá-los. Face ao exposto, a presente pesquisa teve como objetivos: desenvolver uma escala, com indicadores de validade e confiabilidade satisfatórios, para analisar a percepção do consumidor sobre os riscos relacionados ao consumo de saladas de hortaliças cruas em restaurantes à la carte; examinar a frequência de uso, pelo consumidor, de estratégias redutoras dos riscos físicos, no contexto estudado; identificar o perfil dos frequentadores de restaurantes à la carte e consumidores de saladas de hortaliças cruas neste tipo de estabelecimento; e avaliar associações entre as variáveis estudadas (percepção de risco, frequência de uso das estratégias redutoras de risco e frequências de consumo) e as características sociodemográficas do consumidor e, quando pertinente, a tendência à desejabilidade social. Uma escala de percepção de risco foi previamente elaborada com base em revisão de literatura, realização de dois grupos focais (envolvendo seis consumidores em cada sessão), avaliação de dez especialistas (validação de conteúdo) e pré-teste (n = 30 consumidores). Duas pesquisas de campo foram realizadas, envolvendo indivíduos adultos, residentes na cidade de Campinas, SP, e que haviam freqüentado restaurantes à la carte no mínimo uma vez nos três meses prévios à realização da pesquisa. Na primeira coleta, 271 consumidores foram entrevistados em dois shopping centers da cidade. Esta coleta teve como objetivo a purificação da escala, sendo avaliadas a correlação item-total, a confiabilidade e a análise fatorial exploratória. Na segunda coleta de dados, 359 consumidores foram entrevistados em um shopping center da região central da cidade, sendo realizadas as etapas de purificação da escala e a validação de construto (análise fatorial confirmatória). Além da escala de percepção de risco, o questionário apresentava 17 estratégias redutoras de risco (elaboradas com base em revisão de literatura e na condução dos dois grupos focais), variáveis sociodemográficas e uma escala para identificar a tendência à desejabilidade social. Com base nos resultados da segunda coleta (n = 359), foram realizadas as análises envolvendo as diferenças nos níveis de riscos percebidos pelo consumidor e na frequência de uso das estratégias de redução de risco em função de variáveis sociodemográficas. As análises envolvendo a frequência de consumo de saladas de hortaliças em restaurantes à la carte foram conduzidas tendo por base os resultados das duas coletas (n = 630). Foram construídos bancos de dados usando os softwares Predictive Analytics Software 18.0 e LISREL 8.80. Análises descritivas foram realizadas e testes não paramétricos foram utilizados para a comparação de médias e correlações. A escala de percepção de risco final apresentou 26 itens e adequada confiabilidade (a de Cronbach = 0,93). A análise fatorial confirmatória validou um modelo de percepção composto por seis tipos de risco: físico, de desempenho, financeiro, de tempo, psicológico e social. Os resultados da aplicação do questionário revelaram que 52,3% dos indivíduos afirmaram se alimentar em restaurantes à la carte no mínimo uma vez por semana. Diferenças significativas (p<0,05) foram observadas ao se considerar as variáveis sociodemográficas e a frequência de consumo em restaurantes à la carte ou a frequência de consumo de saladas. A frequência de consumo de salada neste tipo de restaurante foi significativamente (p<0,05) maior no almoço durante a semana. A desejabilidade social parece não ter influenciado as respostas dos consumidores quanto à frequência de consumo deste tipo de alimento. Os consumidores apresentaram uma moderada percepção de risco, sendo percebidos maiores níveis para os riscos físicos e de desempenho (médias iguais a 24,2, considerando escala que poderia variar entre 1 e 49). A média para o risco social (igual a 8,5) foi significativamente inferior a dos demais tipos de riscos. Diferenças (p<0,05) nos níveis percebidos dos tipos de riscos foram identificadas em função das variáveis sociodemográficas: de forma geral, as mulheres e os indivíduos com menor escolaridade perceberam os maiores níveis de riscos no contexto pesquisado. As estratégias redutoras de risco ¿levo em consideração a aparência geral do restaurante¿, ¿frequento restaurantes que já conheço¿, ¿deixo de frequentar o restaurante no qual já tive alguma experiência desagradável¿ e ¿levo em consideração a higiene geral do restaurante¿ foram as mais frequentemente utilizadas. ¿Visito a cozinha do restaurante¿ foi a estratégia com freqüência de uso significativamente menor que todas as demais. Diferenças (p<0,05) na frequência de uso das estratégias em função das variáveis sociodemográficas foram identificadas. Foi observada correlação positiva significativa (p<0,05) entre a desejabilidade social e algumas estratégias. Conclui-se que a escala de percepção de risco desenvolvida apresenta indicadores adequados de confiabilidade e validade e se espera que os resultados constituam subsídios para os programas públicos (como aqueles voltados a informar o consumidor), bem como forneçam suporte à elaboração de estratégias de crescimento do setor de serviços de alimentação
Abstract: The standard diet of the Brazilian population has been characterized, amongst other aspects, by a reduced consumption of vegetables and by an increasing number of meals eaten away from home, and hence the use of food services could represent an opportunity to include a variety of vegetables in the diet. Consumer behavior when eating away from home has been little studied in Brazil, and could be influenced by the risks perceived in a buying situation. Based on his/her perception of the risks, the consumer could adopt different strategies at the moment of choice, in an attempt to minimize them. With this in mind, the present research had the following objectives: develop a scale with satisfactory validity and reliability indicators to analyze consumer perception with respect to the risks involved in eating raw vegetable salads in full-service restaurants; examine the frequency with which the consumers use strategies to reduce physical risks in the context under study; identify the profile of those frequenting full-service restaurants and eating raw vegetable salads; evaluate associations between the variables studied (risk perception, frequency of use of risk reducing strategies and the frequencies of consumption) and the sociodemographic characteristics and, when pertinent, the tendency for social desirability. A risk perception scale was previously elaborated based on a review of the literature, the carrying out of two focus groups (involving six consumers in each session), the evaluation of ten specialists (content validation) and a pre-test (n = 30 consumers). Two field surveys were also carried out involving adult individuals resident in the city of Campinas, SP, Brazil, all of whom were used to frequenting full-service restaurants at least once in the 3 months prior to the survey. In the first data collection, 271 consumers were interviewed in two shopping centers in the city. The objective of this collection was to purify the scale, and hence the item-total correlation, reliability and exploratory factor analysis were evaluated. In the second data collection, 359 consumers were interviewed in a shopping center in the central region of the city, carrying out the scale purification and construct validation (confirmatory factor analysis) steps. In addition to the risk perception scale, the final questionnaire presented 17 risk-reducing strategies (elaborated based on a review of the literature and the carrying out of two focus groups), socio-demographic variables and a scale to identify a tendency for social desirability. Based on the results of the second collection (n = 359), analyses were carried out involving the differences in the risk levels perceived by the consumer and the frequency of use of the risk-reducing strategies as a function of the socio-demographic variables. The frequency of eating vegetable salads in full-service restaurants was evaluated based on results of both collection (n = 630). Data banks were constructed using the Predictive Analytics 18.0 software and the LISREL 8.80 software. Descriptive analyses were carried out and non-parametric tests used to compare the means and correlations. The final risk perception scale presented 26 items and adequate reliability (Cronbach¿s a coefficient = 0.93). The confirmatory factor analysis validated a perception model composed of six types of risk: physical, performance, financial, time, psychological and social. The results of applying the questionnaire showed that 52.3% of the individuals stated they ate in full-service restaurants at least once a week. Significant differences (p<0.05) were observed when considering the socio-demographic variables and the frequency of eating in full-service restaurants or the frequency of eating salads. The frequency of eating salads in this type of restaurant was significantly higher for weekday lunches and social desirability apparently had no influence on consumer responses with respect to the frequency of eating salads. The consumers showed moderate risk perception, perceiving higher risk levels for physical and performance (means of 24.2 on a scale varying from 1 to 49). The mean for social risk (equal to 8.5) was significantly lower than for the other types of risk. Differences (p<0.05) in the levels perceived for the different types of risk as a function of the socio-demographic variables were identified: in general women and those with lower scholastic levels perceived higher levels of risk in the context surveyed. The most frequently used risk reducing strategies were the following: ¿I take the general appearance of the restaurant into consideration¿, ¿I frequent restaurants I already know¿, ¿I don¿t go back to restaurants where I had an unpleasant experience¿ and ¿I take the general hygiene level of the restaurant into consideration¿. The strategy ¿I visit the restaurant¿s kitchen¿ showed a significantly lower frequency of use than the other strategies. Differences (p<0.05) in the frequency of use of the strategies as a function of the socio-demographic variables were identified and a significant positive correlation (p<0.05) was observed between social desirability and some strategies. It was concluded that the risk perception scale developed showed adequate reliability and validity indicators, and it is hoped that the results provide subsidy for public programs (such as those directed at providing information to the consumer), and provide support for the elaboration of growth strategies for the foodservice sector
Doutorado
Consumo e Qualidade de Alimentos
Doutor em Alimentos e Nutrição

In a changing climate with an increasing risk of flooding, developing a sustainable approach to flood management is paramount. Sustainable Drainage Systems (SuDS) present a change in thinking with regards to drainage; storing water in the urban environment as opposed to rapidly removing it to outflows. The Non-Statutory Standards for SuDS (DEFRA 2015a) presented a requirement for all developments to integrate SuDS in their design to reduce runoff. This research models the impact on water quantity of combining different SuDS devices to demonstrate their success as a flood management system, as compared to conventional pipe based drainage. The research uses MicroDrainage®, the UK industry standard flood modelling tool which has an integrated SuDS function, to simulate the role of SuDS in a management train. As space is often cited as the primary reason for rejecting SuDS, determining the most effective technique at reducing runoff is critical. Detention basins were concluded as being highly effective at reducing peak flow (150 l/s when combined with swales), however Porous Pavement Systems (PPS) was nearly twice as effective per m3, reducing peak flow by up to 0.075 l/s/m3 compared to 0.025 l/s/m3. This therefore suggests that both detention basins and PPS should be high priority devices when developing new sites, but that no matter what combination of modelled SuDS are installed a reduction in runoff in comparison to conventional drainage can be achieved. A SuDS decision support tool was developed to assist design in MicroDrainage® by reducing the time spent determining the number of SuDS required for a site. The tool uses outputs from MicroDrainage® to rapidly predict the minimum and maximum peak flow for a site, in comparison to greenfield runoff, based on the site parameters of area, rainfall rate, infiltration, combined with the planned SuDS. The tool was underpinned by a model analysis for each site parameter and each SuDS device, which produced r2 values >0.8, with 70% above 0.9. This ensured a high level of confidence in the outputs, enabling a regression analysis between runoff and each site parameter and SuDS device at the 99% confidence level, with the outputs combined to create the tool. The final aspect of the research validated MicroDrainage® to analyse the accuracy of the software at predicting runoff. Using field data from Hamilton, Leicester, and laboratory data for PPS and filter drains, a comparison could be made with the output from MicroDrainage®. The field data created a Nash-Sutcliffe Efficiency (NSE) of 0.88, with filter drains and PPS providing an NSE of 0.98 and 0.94 respectively. This demonstrates the success with which MicroDrainage® predicts runoff and provides credibility to the outputs of the research. Furthermore, it offers SuDS specialists the confidence to use MicroDrainage® to predict runoff when using SuDS.

Includes bibliographical references.
TB is an airborne infectious disease which is spread by droplet nuclei, carrying Mycobacterium tuberculosis, in the air. The droplet nuclei small enough to enter human respiratory pathways are 1-5 μm in size and are able to travel long distances (Hodgson, et al., 2009) (WHO, 1999), and can be distributed widely throughout (hospital) buildings (Beggs, Noakes, Sleigh, Fletcher, & Siddiqi, 2003). These droplet nuclei may remain suspended in the air until they are removed by dilution ventilation or other disinfection methods (Parsons, Hussey, Abbott, & de Jager, 2008) (National Department of Health, 2007). Dilution ventilation refers to the dilution of contaminated air with “clean” air (ACGIH, 2005), thereby reducing the concentration of contaminants in the room. One of the recognised approaches for minimising the risk of transmission of TB is to adequately ventilate the contaminated room/space. A higher ventilation rate can provide higher dilution capability, in turn reducing the risk of airborne infections (WHO, 2009). The parameters of concern in ventilation design are ventilation flow rate and airflow pattern in the room (and building). The former reduces contaminant concentration while the latter aims to move uncontaminated air to high risk areas, and contaminated air away from occupied areas, usually to the outside. The shortcomings of conventional natural ventilation strategies are well documented. The aim of this research project is to review and study the effectiveness of natural ventilation design supplemented by a turbine ventilator. The project was divided into two components: a field study and laboratory experiments. In the field study, a turbine ventilator was installed into a bedroom of a low-income house in Pretoria. Tracer gas (concentration decay) tests were performed to determine the ventilation flow rates, mean age of air and air change efficiency of four natural ventilation configurations. These included infiltration/leakage (IL), two cases of single-sided ventilation (SS1 and SS2), and crossventilation (CV). Three baseline (without the turbine ventilator) and three turbine ventilator tests were performed, one each in the morning, noon and afternoon. The tests were performed between February and April 2011 on typical summer days. The turbine ventilator was then tested in a laboratory environment under wind, buoyancy and a combination of wind and buoyancy forces. The wind speeds were low, ranging from 0.0 to 0.5 m/s (0.0 to 1.8 km/h), and the temperature differential tested was in the range of 5.5 to 9.3˚C. The in-duct velocities and centreline velocities were investigated to establish if, under the subjected force(s), a capture envelope described by Dalla Valle’s equation could be measured. This envelope would be used to determine if the turbine ventilator could potentially reduce the concentration of airborne contaminants in the test volume. In the field study baseline tests, IL, SS1, CV and SS2 mean – and range of - ventilation flow rates of 0.6 [0.5 – 0.6], 8.1 [6.8 – 9.3], 16.9 [14.7 – 19.0] and 7.4 [7.0 – 7.9] ACH, respectively, were reported. The baseline tests highlight the potential of cross-ventilation where, by simply opening windows and doors, a ventilation rate exceeding IPC recommendations was obtained. All configurations, save An investigation into turbine venti lators as a potential environmental co ntrol measur e to minimise the risk of transmission on TB Page IV SS1, appear to have approached the fully-mixed case.SS1 also showed the greatest variability in ventilation flow rates. This finding is not unexpected, as air exchange in single-sided ventilation is due to wind pressure fluctuations, which varied across each test. In addition, in all tests it was found that the ventilation flow rate was dependant on the natural ventilation configuration and openable area, and not necessarily environmental conditions. In the turbine ventilator tests, the mean ventilation flow rates for IL, SS1, CV and SS2 were 1.8 [1.6 – 2.1], 5.4 [5.2 – 5.7], 17.7 [16.0 – 18.6] and 9.5 [8.5 – 10.1] ACH, respectively. The mean ventilation flow rate increased in IL and SS2 with the installation of the turbine ventilator, while in SS1 a decrease was reported. The increase in ventilation flow rate in IL was found to be due to natural convection, where the turbine ventilator merely facilitated the exhaustion of warm air. The results of the field study are specific to the environmental conditions at the time of the test, and are not generalizable. In the laboratory experiments, the in-duct velocity increased with an increase in wind speed and temperature differential. For a given temperature differential, an increase in wind speed resulted in a decrease in in-duct velocity. Across all tests, no centreline velocity profile, described by the Dalla Valle equation, could be measured. In the wind speed tests, no capture envelope could be established. This was due to the low wind speed test range, where the resulting centreline velocity was beyond the limit of detection of the thin-film sensors. In the buoyancy forces test, a turbulent region near the base of the turbine ventilator was realised, where the magnitude and direction of the air flowing at 1.5D continuously changed. This turbulent region was again observed in the combined wind and buoyancy forces tests, though the magnitude was smaller and occurrence less frequent. The results of the laboratory experiments are specific to the parameters tested, and are not generalizable. By correlating the field study, laboratory experiments, and previous (similar) studies, it was concluded, that, under the tested conditions, adding a turbine ventilator as a supplement to natural ventilation system will not reduce the concentration of contaminants in the occupied zone in a room.

Cette thèse de doctorat est consacrée à l’étude sur le risque d’inflammation de gaz imbrûlés au niveau du système de ventilation suite à un incendie dans un milieu confiné sous-ventilé. La caractérisation de l’état de stratification des fumées et du désenfumage apparaît aussi comme un objectif. Lors d’un incendie en milieu clos, la quantité d’oxygène présente dans le local peut devenir insuffisante, engendrant une combustion incomplète. Des gaz chauds imbrûlés résiduels peuvent alors s’accumuler dans le local et être évacués par la ventilation d’extraction. Lorsque ces derniers sont mis en présence d’air apporté par un autre conduit de ventilation, ils peuvent s’enflammer spontanément et générer une déflagration pouvant rompre le confinement dynamique des matières dangereuses, situation inacceptable pour la sûreté des installations nucléaires. Cette inflammation dépend de la quantité des imbrûlés, de la température dans la gaine d’extraction et de la concentration minimale en oxygène. L’objectif de cette étude est de quantifier et d’analyser ce risque par l’étude aérodynamique de la flamme et par le niveau de confinement dynamique afin de choisir le type de ventilation présentant le moins de risque. Cette étude, à la fois numérique et expérimentale, permet d’améliorer la compréhension de l’influence de la richesse globale liée au niveau de confinement de l’enceinte sur la production d’imbrûlés comme CO, H2 et fuel. Elle permet par la suite de mettre en évidence l’influence de celle-ci sur le risque d’inflammation de gaz imbrûlés au niveau du système de ventilation
This doctoral thesis is devoted to the study of the risk of ignition of unburnt gases in the ventilation system after a fire in an under-ventilated confined enclosure. The characterization of the state of lamination of smoke and smoke extraction also appears as an objective. In a closed fire, the amount of oxygen present in the room may become insufficient leading to incomplete combustion. Residual unburnt hot gases can then accumulate in the room and be evacuated by extraction ventilation. When the latter are placed in the presence of air supplied by another ventilation duct, they can ignite spontaneously and generate a deflagration capable of breaking the dynamic containment of hazardous materials, an unacceptable situation for the safety of nuclear installations. This ignition depends on the quantity of the unburned gases, the temperature in the extraction sheath and the minimum concentration of oxygen. The objective of this study is to quantify and analyze this risk through the aerodynamic study of the flame and the level of dynamic confinement in order to choose the ventilation posing the least possible risk. This study, both numerical and experimental, makes possible to improve the understanding of the influence of the equivalence ratio linked to the level of confinement of the enclosure on the production of unburned like CO, H2 and fuel. Then, it makes possible to highlight the influence of the latter on the risk of ignition of unburnt gases in the ventilation network

L'objectif de cette thèse est d'étudier la réalisation d'un équilibre dans un marché où les prix des actifs financiers sont discontinus et sur lequel les agents sont différemment informés. Dans une première partie, nous résolvons le problème d'optimisation d'un initié qui possède une information forte initiale, i.e. il connaît dès le début une fonctionnelle des trajectoires du processus des prix. Nous établissons, sous une hypothèse d'indépendance de tribus, une condition nécessaire et suffisante d'existence d'un équilibre, défini par le fait que le marché des consommations s'équilibre. Nous montrons qu'à l'équilibre le marché révèle toutes les informations pertinentes. Dans une deuxième partie, nous étudions deux autres modélisations de l'information privée. La première est l'information forte progressive : l'information privée est perturbée par un bruit indépendant qui décroît au cours du temps. La deuxième s'appelle information faible : l'agent sait qu'une information concernant une variable aléatoire va être révélée, il ne peut pas l'observer mais il anticipe sa loi. D'un point de vue mathématique, l'information privée de l'initié n'est plus exprimée par une augmentation de filtration (à la différence d'une information forte, initiale ou progressive) mais par une mesure de probabilité différente assignée à cet agent. Enfin, nous avons étudié la formation d'un équilibre avec plusieurs agents initiés ayant des informations différentes. Nous avons plus particulièrement examiné sous quelles conditions la somme de leur portefeuille est nulle. Nous avons montré que plus un agent est informé sur le marché, plus il doit rester discret et investir peu sur ce marché, afin qu'un équilibre puisse exister. Dans la dernière partie, nous avons simulé les stratégies d'initiés pour différentes informations privées et nous les avons comparées à la stratégie optimale d'un non-initié. Nous avons aussi simulé la formation d'un équilibre et le montant maximal que peut investir un initié dans le marché sans empêcher un équilibre d'avoir lieu.

碩士
中華大學
工業管理學系
107
Many companies have found that traditional organizations cannot effectively manage all kinds of projects in a highly competitive market environment at present. It is necessary to make breakthroughs in various aspects such as increasing productivity, reducing production costs, and improving management methods. However, the factors in the activities of the project are interlocking such as time, cost and risk. In this case, as long as some factors cannot be expected, the whole project will be affected. When the progress of the project is postponed, it is necessary to adopt a compression strategy. Using the crashing or fast tracking method to bring the late progress back to the original schedule will increase the cost and risk of the project. This study hopes to develop a mathematical model to explore how to choose the implementation method that is most suitable for the project activities to minimize the risk and cost. The model is verified by virtual cases, and then the best solution is obtained by using LINGO software.

Steady-state unit-operations are globally used in chemical engineering. Advantages include ease of control and a uniform product quality. Nonetheless there will be naturally occurring, random (stochastic) fluctuations about any steady-state ‘set’ value of a process parameter. Traditional chemical engineering does not explicitly take account of these. This is because, generally, fluctuation in one parameter appears to be off-set by change in another – with the process outcome remaining apparently steady. However Davey and co-workers (e.g. Davey et al., 2015; Davey, 2015 a; Zou and Davey, 2016; Abdul-Halim and Davey, 2016; Chandrakash and Davey, 2017 a) have shown these naturally occurring fluctuations can accumulate and combine unexpectedly to leverage significant impact and thereby make apparently well-running processes vulnerable to sudden and surprise failure. They developed a probabilistic and quantitative risk framework they titled Fr 13 (Friday 13th) to underscore the nature of these events. Significantly, the framework can be used in ‘second-tier’ studies for re-design to reduce vulnerability to failure. Here, this framework is applied for the first time to show how naturally occurring fluctuations in peak ambient temperature (T₀) and occupancy (room traffic flows) (Lᴛ) can impact heat transfers for conditioning of room air. The conditioning of air in large buildings, including hotels and hospitals, is globally important (Anon., 2012 a). The overarching aim is to quantitatively ‘use’ these fluctuations to develop a strategy for minimum energy. A justification is that methods that permit quantitative determination of reliable strategies for conditioning of air can lead to better energy use, with potential savings, together with reductions in greenhouse gases (GHG). Oddly many buildings do not appear to have a quantitative strategy to minimize conditioning heat transfers. Wide-spread default practice is to simply use an on-off strategy i.e. conditioning-on when the room is occupied and conditioning-off, when un-occupied. One alternative is an on-only strategy i.e. leave the conditioner run continuously. A logical and stepwise combined theoretical-and-experimental, approach was used as a research strategy. A search of the literature showed that work had generally focused on discrete, deterministic aspects and not on mathematically rigorous developments to minimise overall whole-of-building conditioning heat transfers. A preliminary steady-state convective model was therefore synthesized for conditioning air in a (hotel) room (4.5 x 5.0 x 2.5, m) in dry, S-E Australia during summer (20 ≤ T₀ ≤ 40, °C) to an auto-set room bulk temperature of 22 °C for the first time. This was solved using traditional, deterministic methods to show the alternative on-only strategy would use less electrical energy than that of the default on-off for Lᴛ > 36 % (Chu et al., 2016). Findings underscored the importance of the thermal capacitance of a building. The model was again solved using the probabilistic Fr 13 framework in which distributions to mimic fluctuations in T₀ and Lᴛ were (reasonably) assumed and a new energy risk factor (p) was synthesized such that all p > 0 characterized a failure in applied energy strategy (Chu and Davey, 2015). Predictions showed on-only would use less energy on 86.6 % of summer days. Practically, this meant that a continuous on-only strategy would be expected to fail in only 12 of the 90 days of summer, averaged over the long term. It was concluded the Fr 13 framework was an advance over the traditional, deterministic method because all conditioning scenarios that can practically exist are simulated. It was acknowledged however that: 1) a more realistic model was needed to account for radiative heat transfers, and; 2) to improve predictive accuracy, local distributions for T₀ and Lᴛ were needed. To address these: 1) the model was extended mathematically to account for radiative transfers from ambient to the room-interior, and; 2) distributions were carefully-defined based on extensive historical data for S-E Australia from, respectively, Bureau of Meteorology (BoM) (Essendon Airport) and Clarion Suites Gateway Hotel (CSGH) (Melbourne) – a large (85 x 2-room suites) commercial hotel (latitude -37.819708, longitude 144.959936) – for T₀ and Lᴛ for 541 summer days (Dec. 2009 to Feb. 2015) (Chu and Davey, 2017 a). Predictions showed that radiative heat transfers were significant and highlighted that for Lᴛ ≥ 70 %, that is, all commercially viable occupancies, the on-only conditioning strategy would be expected to use less energy. Because findings predicted meaningful savings with the on-only strategy, ‘proof-of-concept’ experiments were carried out for the first time in a controlled-trial in-situ in CSGH over 10 (2 x 5 contiguous) days of summer with 24.2 ≤ T₀ ≤ 40.5, °C and 13.3 ≤ Lᴛ ≤ 100, %. Independent invoices (Origin Energy Ltd, or Simply Energy Ltd, Australia) (at 30 min intervals from nationally registered ‘smart’ power meters) for geometrically identical control and treated suites showed a mean saving of 18.9 % (AUD $2.23 per suite per day) with the on-only strategy, with a concomitant 20.7 % reduction (12.2 kg CO₂-e) in GHG. It was concluded that because findings supported model predictions, and because robust experimental SOPs had been established and agreed by CSGH, a large-scale validation test of energy strategies should be undertaken in the hotel. Commercial-scale testing over 77 contiguous days of summer (Jan. to Mar., 2016) was carried out in two, dimensionally-identical 2-room suites, with the same fit-out and (S-E) aspect, together with identical air-conditioner (8.1 kW) and nationally registered meters to automatically transmit contiguous (24-7) electrical use (at 30 min intervals) (n = 3,696) for the first time. Each suite (10.164 x 9.675, m floor plan) was auto-set to a bulk air temperature of 22 °C (Chu and Davey, 2017 b). In the treated suite the air-conditioner was operated on-only, whilst in the control it was left to wide-spread industry practice of on-off. The suites had (standard) single-glazed pane windows with heat-attenuating (fabric) internal curtains. Peak ambient ranged from 17.8 ≤ T₀ ≤ 39.1, °C. There were 32 days with recorded rainfall. The overall occupancy Lᴛ of both suites was almost identical at 69.7 and 71.2, % respectively for the treated and control suite. Importantly, this coincided with a typical business period for the CSGH hotel. Based on independent electrical invoices, results showed the treated suite used less energy on 47 days (61 %) of the experimental period, and significantly, GHG was reduced by 12 %. An actual reduction in electrical energy costs of AUD $0.75 per day (9 %) averaged over the period was demonstrated for the treated suite. It was concluded therefore that experimental findings directly confirmed the strategy hypothesis that continuous on-only conditioning will use less energy. Although the hypothesis appeared generalizable, and adaptable to a range of room geometries, it was acknowledged that a drawback was that extrapolation of results could not be reliably done because actual energy used would be impacted by seasons. The in-situ commercial-scale experimental study was therefore extended to encompass four consecutive seasons. The research aim was to provide sufficient experimental evidence (n = 13,008) to reliably test the generalizability of the on-only hypothesis (Chu and Davey, 2017 c). Ambient peak ranged from 9.8 ≤ T₀ ≤ 40.5, °C, with rainfall on 169 days (62 %). Overall, Lᴛ was almost identical at 71.9 and 71.7, % respectively, for the treated and control suite. Results based on independent electrical energy invoices showed the on-only strategy used less energy on 147 days (54 %) than the on-off. An overall mean energy saving of 2.68 kWh per suite per day (9.2 %) (i.e. AUD $0.58 or 8.0 %) with a concomitant reduction in indirect GHG of 3.16 kg CO₂-e was demonstrated. Extrapolated for the 85 x 2-room suites of the hotel, this amounted to a real saving of AUD $18,006 per annum - plus credit certificates that could be used to increase savings. Overall, it was concluded therefore the on-only conditioning hypothesis is generalizable to all seasons, and that there appears no barrier to adaption to a range of room geometries. Highly significantly, the methodology could be readily applied to existing buildings without capital outlays or increases in maintenance. A total of five (5) summative research presentations of results and findings were made to the General Manager and support staff of CSGH over the period to July 2017 inclusive (see Appendix I) that maintained active industry-engagement for the study. To apply these new findings, the synthesis of a computational algorithm in the form of a novel App (Anon., 2012 b; Davey, 2015 b) was carried out for the first time (Chu and Davey, 2017 d). The aim was to demonstrate an App that could be used practically to minimize energy in conditioning of dry air in buildings that must maintain an auto-set temperature despite the impact of fluctuations in T₀ and Lᴛ . The App was synthesized from the extensive experimental commercial-scale data and was applied to compute energy for both strategies from independently forecast T₀ and Lᴛ . Practical performance of the App was shown to be dependent on the accuracy of locally forecast T₀ and Lᴛ . Overall results predicted a saving of 2.62 kWh per 2-room suite per day ($47,870 per annum for CSGH) where accuracy of forecast T₀ is 77 % and Lᴛ is 99 %, averaged over the long term. A concomitant benefit was a predicted reduction greenhouse emissions of 3.1 kg CO₂-e per day. The App appears generalizable – and importantly it is not limited by any underlying heat-model. Its predictive accuracy can be refined with accumulation of experimental data for a range of geo-locations and building-types to make it globally applicable. It was concluded that the App is a useful new tool to minimize energy transfers in conditioning of room dry air in large buildings – and could be readily developed commercially 6. Importantly, it can be applied without capital outlays or additional maintenance cost and at both design and analysis stages. This research is original and not incremental work. Results of this research will be of immediate benefit to risk analysts, heat-design engineers, and owners and operators of large buildings.
Thesis (Ph.D.) -- University of Adelaide, School of Chemical Engineering, 2018

Кваліфікаційна робота магістра складається з трьох розділів. Об’єкт дослідження – кредитування у діяльності комерційного банку з урахуванням ризикованості. У роботі розглядаються теоретичні аспекти кредитної політики комерційного банку та мінімізації кредитних ризиків. Проаналізовано банківське кредитування, обсяги капіталу, структуру та динаміку кредитного портфелю на прикладі ПАТ «Альфа Банку». Запропоновано шляхи удосконалення організації кредитного процесу та напрямки оптимізації кредитної політики банку.
Квалификационная работа магистра состоит из трех разделов. Объект исследования – кредитования в деятельности коммерческого банка с учетом рискованности. В работе рассматриваются теоретические аспекты кредитной политики коммерческого банка и минимизации кредитных рисков. Проанализированы банковское кредитование, объемы капитала, структуру и динамику кредитного портфеля на примере ОАО «Альфа Банка». Предложены пути совершенствования организации кредитного процесса и направления оптимизации кредитной политики банка.
Thesis consists of three chapters. Object of study – bank’s credit policy. Diploma thesis deals with theoretical aspects of credit policy and credit risk. Defined the essence of monetary policy, conducted a critical analysis of scientific definitions of the term «credit policy of the bank.» The essence of the concept of «credit risk». The methods of credit risk and indicating ways to minimize it.

abstract: A roofing manufacturer wants to differentiate themselves from other roofing manufacturers based on performance information. However, construction industry has revealed poor performance documentation in the last couple of decades. With no current developed performance measurement model in the industry, two roofing manufacturers approached the research group to implement a warranty program that measures the performance information of their systems and applicators. Moreover, the success of any project in the construction industry heavily relies upon the capability of the contractor(s) executing the project. Low-performing contractors are correlated with increased cost and delayed schedules, resulting in end-user dissatisfaction with the final product. Hence, the identification and differentiation of the high performing contractors from their competitors is also crucial. The purpose of this study is to identify and describe a new model for measuring manufacturer performance and differentiating contractor performance and capability for two roofing manufacturers (Manufacturer 1 and Manufacturer 2) in the roofing industry. The research uses multiple years of project data and customer satisfaction data collected for two roofing manufacturers for over 1,000 roofing contractors. The performance and end-user satisfaction was obtained for over 7,000 manufacturers' projects and each contractor associated with that project for cost, schedule, and quality metrics. The measurement process was successfully able to provide a performance measurement for the manufacturer based on the customer satisfaction and able to identify low performing contractors. This study presents the research method, the developed measurement model, and proposes a new performance measurement process that entities in the construction industry can use to measure performance.
Dissertation/Thesis
Doctoral Dissertation Construction 2016

The main objective of the work developed in this thesis was to address spent caustic treatment as a way to decrease the high organic load of this effluent and reduce its great impact on the quality of the wastewater sent to wastewater treatment plants, particularly in terms of oil and grease (O&G) contamination. The naphthenic spent caustic generated by Galp refinery in Sines was used as case study. Spent caustic effluents are very challenging due to their very hazardous nature in terms of toxicity as well as their extreme pH (approximately 12-13). Spent caustic treatment is presently a challenge for refineries, due to its composition rich in mercaptans, sulphides and other aromatic compounds. In general, proton nuclear magnetic ressonance (NMR), Fourier transform infrared spectroscopy (FT-IR) and gas chromatography mass spectromery (GC-MS) analyses suggested that aromatic structures account for a significant part of the organic structures that constitute naphthenic spent caustic, which are also present in the final wastewater. It was found that acid crudes processing with lower molecular-weight acid components seem to have a great impact on polar O&G concentration increase in spent caustic and therefore in the final wastewater. Nanofiltration (NF) is a very effective technology when treatment and separation/recovery of specific components is required since it is able to remove low molecular weight organic molecules like hydrocarbons and phenolic compounds. The potential application of polymeric and ceramic membranes was addressed by conducting ageing studies (only in the case of polymeric membranes) and NF experiments to assess their retention properties and lifespan. Contrarily to expectations, neither of the tested types of membranes presented attractive results for spent caustic treatment, due to very quick losses of their retention properties; analysis by FT-IR and Inductively coupled plasma atomic emission spectroscopy (ICPAES) corroborated the ocurrence of desintegration mechanisms in the structure of the tested membranes. A different strategy based on chemical treatments was followed to treat spent caustic: (i) neutralization, followed by Fenton oxidation post-treatment (approach 1) and (ii) neutralization, followed by liquid-liquid extraction (approach 2). Approach 1 (lab scale tests) allowed to remove 95 % of polar O&G, with a 70% decrease in the acute toxicity after treatment. Approach 2 (pilot scale tests) allowed to remove 99 % of polar O&G. Both technologies allowed direct discharge of treated spent caustic into the Sines refinery wastewater circuit, with approach 2 being the best option since it presented the highest annual savings (1.5 yearly effluent management cost. The results obtained in the present thesis may be useful for the development/optimization of industrial-scale plants in petroleum refineries for the treatment of naphthenic spent caustic effluents, providing an effective treatment technology proposal, with interesting effluent management cost reduction.
O presente trabalho teve como principal objetivo o tratamento da soda exausta como forma de diminuir a elevada carga orgânica deste efluente e assim reduzir o seu impacto no efluente final descarregado para a estação de tratamento, particularmente em termos da contaminação por óleos e gorduras (O&G). Para tal, a soda exausta nafténica produzida na refineria de Sines (Galp) foi utilizada como caso de estudo. A soda exausta constitui um verdadeiro desafio devido à sua natureza tóxica e ao seu pH extremo (aproximadamente 12-13). Este efluente tem-se apresentado como um enigma para as refinarias no que concerne ao tratamento de efluentes, tendo em conta a sua composição rica em mercaptanos, sulfuretos e outros compostos aromáticos. No geral, as análises de ressonância magnética nuclear de protão (NMR), espectroscopia de infravermelho com transformada de Fourier (FT-IR) e cromatografia gasosa com espectroscopia de massa (GC-MS) sugerem que as estruturas aromáticas representam uma parte significativa das estruturas orgânicas que constituem a soda exausta nafténica, as quais também estão presentes no efluente final. Verificou-se que o processamento de crudes ácidos com compostos ácidos de baixo peso molecular apresentam maior impacto no aumento da concentração de O&G de natureza polar na soda exausta e por consequência no efluente final. A nanofiltração (NF) caracteriza-se por ser uma tecnologia eficiente quando o tratamento e separação/recuperação de compostos específicos é necessário, uma vez que consegue remover moléculas orgânicas de baixo peso molecular como hidrocarbonetos e compostos fenólicos. O potencial de tratamento da soda exausta foi estudado com membranas polimérica e cerâmica, avaliando-se para tal o tempo de vida útil das membranas (apenas no caso da membrana polimérica). Contrariamente às expectativas, nenhum dos tipos de membranas testados apresentou resultados interessantes para o tratamento da soda exausta, devido a perdas muito rápidas de propriedades retentivas; efetivamente, análises por FT-IR e espectroscopia de emissão atómica de indução por plasma e espectroscopia de absorção atómica com câmara de grafite (ICP-AES) corroboraram a ocorrência de mecanismos de desintegração na estrutura das membranas testadas. Foi testada uma estratégia diferente para tratar a soda exausta, baseada em tratamentos químicos: (i) neutralização, seguida de oxidação Fenton como pós-tratamento (1ª abordagem) e (ii) neutralização, seguida de extração líquido-líquido (2ª abordagem). A 1ª abordagem (realizada à escala laboratorial) permitiu remover 95 % de O&G de natureza polar, com uma redução de 70 % da toxicidade aguda após tratamento. A 2ª abordagem (realizada à escala piloto) permitiu remover 99 % de O&G de natureza polar. Ambas as tecnologias produziram um efluente tratado com características aceitáveis para descarga no circuito de tratamento de efluentes da refinaria de Sines. A 2ª abordagem foi considerada a melhor opção, uma vez que apresentou a maior poupança no custo anual com a Os resultados obtidos na presente tese poderão ser úteis no desenvolvimento/otimização de unidades à escala industrial em refinarias de petróleo para o tratamento de sodas exaustas nafténicas, providenciando para tal uma proposta de tecnologia de tratamento eficiente, com uma redução interessante no custo anual com a gestão de efluentes.