[pt] Este trabalho faz uma análise da variação dos parâmetros que têm importância na propagação de fraturas hidráulicas e da influência desses parâmetros na conten-ção do fraturamento. Os experimentos numéricos foram feitos em um modelo 2D utilizando um simulador de elementos finitos com acoplamento sequencial hidro-dinâmico, tendo como premissa o comportamento dos processos envolvidos em es-tado estacionário. Inicialmente foram feitos testes de validação das soluções numé-ricas empregadas neste trabalho a partir de casos cujas soluções são bem conheci-das. Então, efeitos de variações de poropressão, de estado de tensões, propriedades das rochas, intervalos de início da fratura hidráulica, efeitos térmicos e o dano à permeabilidade da formação permoporosa foram utilizados para avaliar a contenção da fratura hidráulica. Primeiramente os efeitos foram avaliados separadamente e, em seguida, foram combinados aos pares, por meio de sorteio, e então avaliados. Os estudos levaram à conclusão de que o fator de maior influência para o início da propagação da fratura hidráulica na rocha capeadora (primeiros metros) é o valor da tensão mínima de confinamento do reservatório e a continuidade da propagação vertical na rocha selante é dominada pelo contraste de tensões entre rochas reserva-tório e capeadora. Entretanto, os demais parâmetros exercem influência na conten-ção do fraturamento hidráulico e devem ser levados em consideração neste tipo de estudo, principalmente os que servirão de insumo para a tomada de decisões. / [en] This master thesis analyzes the parameter s variation on the hydraulic frac-ture s propagation importance and the influence of these parameters on fracture containment. The numerical experiments were performed in a 2D model using a finite element simulator with sequential hydrodynamic coupling, having the sta-tionary behavior of the processes involved as premise. Validation tests were ini-tially performed for the numerical solutions used in this thesis from cases which solutions are well known. Then, effects of pore pressure variations, stress state, rock properties, hydraulic fracture opening intervals, thermal effects, and damage to the permoporous formation were used to evaluate the hydraulic fracture containment. At first, the effects were evaluated separately, then sorted for pair combinations, so they could be analyzed. These analyzes led to the conclusion that the most influen-tial factor for the hydraulic fracture initial propagation in the cap rock (first meters) is the reservoir’s minimum confinement stress value, and the vertical propagation continuity in the sealing rock is dominated by the stress contrast between reservoir and cap rocks. However, other parameters influence the hydraulic fracturing con-tainment and should be considered for this type of study, especially those that will serve as input for decision-making.

Integrating more renewable energy sources into the grid has caused increased instability due to the intermittency of renewable energy sources. Hence, the need for grid balancing strategies such as frequency regulation has intensified. Areim, a Nordic real estate investment company, through this thesis, aims to have an assessment conducted to estimate the environmental benefits or consequences of using their specific battery system as a participant in the Swedish frequency regulation market, using the lifecycle assessment framework. The study only considered the cradle-to-gate lifecycle scope, excluding the product disposal stage, and the impact categories used align with the Environmental Footprint assessment methodology. The functional unit is in per kilo-watthour delivered, and the batteries are expected to deliver 933 kWh of electric energy over the estimated lifetime of 15 years. The normalized carbon emissions caused by delivering 1 kWh of energy for frequency regulation using the status quo prequalified technologies primarily comprised of hydropower, combined heat and power, and battery energy storage produce 4.75 kgCO2eq. Introducing Areim's specific battery system 200 kW bid into the prequalified technologies mix by substitution produces 0.075 kgCO2eq fewer carbon emissions per kWh delivered. The sensitivity analysis further supports that Areim will yield added carbon emission savings by increasing its available prequalified re-source capacity in the market. The findings of this thesis can be used to support Areim and other companies interested in grid support services such as frequency regulation to decide whether it is beneficial to use their specific battery systems for such services from an environmental effect perspective.

As the share of power electronics-based renewable energy sources increases in power systems, the system inertia provided by conventional generation is reduced. Inertia is an important factor in the grid's frequency stability, and with its reduction comes challenges to ensure the reliability of the grid. The frequency stabilising service of frequency containment reserves will need to work in conjunction with the faster, stabilising service of fast frequency reserves to avoid power failures in case of sudden disturbances. This project aims to examine the impact of inertia and methods of improving frequency stability in a future low inertia power system. The frequency behaviour is studied using a simplified and linearised model of the Nordic power system implemented in Matlab/Simulink. The model is extended by implementing supplementary battery control to support the frequency response. The simulation results show that there is an evident correlation between the reduction of system inertia and frequency instability. Moreover, it is concluded that the implemented battery support is successful in stabilising frequency following a disturbance. / Då andelen kraftelektronikbaserade förnybara energikällor ökar i kraftsystem så kommer systemets tröghet, tillfört av konventionell generering av elektricitet, att minska. Trögheten är en viktig faktor för elnätets frekvensstabilitet. Då trögheten minskar utmanas tillförlitligheten av elnätet. Frekvensstabiliserande frekvenshållningsreserver behöver fungera i samspel med de snabbare och stabiliserade frekvensreserverna för att undvika strömavbrott vid plötsliga störningar. Projektet ämnar undersöka trögheten och metoder som används vid förbättring av frekvensstabilitet i framtida kraftsystem med låg tröghet. Beteendet hos frekvenser studeras med en förenklad och linjäriserad modell av det nordiska kraftsystemet implementerat i Matlab/Simulink. Modellen utökas genom att inkludera en batterikontrollmetod för att tillförse ett snabbt frekvenssvar. Resultatet av simuleringarna visar att det finns en korrelation mellan minskning av systemets tröghet och frekvensinstabilitet. Vidare visas det att implementationen av batteristöd lyckas förbättra frekvensen i fallet av en störning. / Kandidatexjobb i elektroteknik 2022, KTH, Stockholm

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In the search for green energy to combat climatechange, a shift from conventional energy sources such as coal,oil, and nuclear towards Renewable Energy Sources (RES) isneeded. This shift poses a threat to the stability of the powergrids as RES do not contribute with rotating mass in the system.A lack of rotating mass, or in other words inertia, jeopardizesthe ability of power systems to counteract large disturbances.Frequency Containment Reserves (FCR) units are responsiblefor controlling the frequency in power systems by regulatingthe balance between the generated and consumed power. If thefrequency deviates outside of the defined range from the nominalvalue, it can lead to system separation, blackouts, and systemequipment damage. The frequency deviations are faster in lowinertia systems, making it more difficult for FCR to keep thefrequency within accepted ranges. Hydro turbines are often usedas FCR units, but additional means of support could be neededfor low inertia systems. Viable support could be battery systems.This project investigates the change towards low inertia and thepossible implementation of a battery system as fast step-wisepower support with a frequency trigger. The investigation is donethrough case studies of simulated system models in Matlab andSimulink. / I jakten på grön energi för att bekämpaklimatförändringarna behövs en övergång från konventionellaenergikällor som kol, olja och kärnkraft mot förnyelsebaraenergikällor. Denna övergång utgör ett hot mot kraftnätensstabilitet då förnyelsebara energikällor inte bidrar med roterandemassa. Brist på roterande massa eller med andra ord tröghetäventyrar kraftsystemens förmåga att motverka stora störningar.Frequency Containment Reserves (FCR) är system som aktivt arbetarmed att styra frekvensen i kraftsystemet genom att reglerabalansen mellan den producerade och konsumerade effekten.Om detta misslyckas och frekvensen avviker för mycket frånden nominella frekvensen kan detta leda till systemseparation,strömavbrott eller skada hos systemkomponenter. I ett systemmed låg tröghet blir frekvensavvikelserna snabbare. Detta gördet svårare att använda sig av FCR för att hålla frekvenseninom accepterade intervall. Vattenkraftverk används ofta somFCR enheter, men för system med låg tröghet kan ytterliggarestöd behövas. Ett möjligt effektstöd kan vara batterisystem.Detta projekt undersöker förändringen till lägre tröghet i ettkraftsystem och möjlig implementering av ett batterisystemmed ett snabbt stegsvar för effektstöd, vilket aktiveras vid enförbestämd frekvens. Undersökningen görs genom studier avspecifika fall med en linjäriserad modell av ett kraftsystemet,simulerade i Matlab och Simulink. / Kandidatexjobb i elektroteknik 2021, KTH, Stockholm

[pt] Este trabalho propõe um método para hierarquizar a contribuição de diferentes estratégias para conter a evolução da pandemia de COVID-19 em diferentes estados do Brasil, nos períodos pré- e pós-vacinação. O método proposto incluiu o aprendizado automático de modelos de regressão utilizando o algoritmo de aprendizado de máquina XGBoost, e aplicou a teoria dos jogos cooperativos de Shapley para quantificar a contribuição das características analisadas para a variável-alvo. Para interpretar o modelo globalmente, foi usado o SHapley Additive exPlanations (SHAP), que é um algoritmo baseado na teoria de Shapley. Os resultados de avaliação do método apontaram a sua eficácia para quantificar a contribuição de cada variável de forma robusta, e revelam que os percentuais de cobertura vacinal de primeira e segunda dose, além do fechamento das escolas, foram as medidas que tiveram maior contribuição na evolução do número de casos e óbitos por COVID-19. A ponderação das variáveis pode ajudar os atores responsáveis na elaboração de políticas públicas para minimizar os efeitos socioeconômicos em suas regiões, dado que o Brasil é um país que possui extrema desigualdade social. / [en] This work proposes a method to rank the contribution of different strategies to contain the evolution of the COVID-19 pandemic in different states of Brazil, in the pre- and post-vaccination periods. The proposed method included the automatic learning of regression models using the XGBoost machine learning algorithm, and applied Shapley s cooperative game theory to quantify the contribution of the analyzed characteristics to the target variable. To interpret the model globally, the SHapley Additive exPlanations (SHAP) was used, which is an algorithm based on Shapley s theory. The evaluation results point to its efficacy to quantify the contribution of each variable in a robust way, and reveal that the percentages of first and second dose vaccination coverage, in addition to the closing of schools, were the measures that had the greatest contribution in the evolution of the number of cases and deaths due to COVID-19. The weighting of variables can help the actors responsible in the elaboration of public policies to minimize the socioeconomic effects in their regions, since Brazil is a country that has extreme social inequality.

[pt] Somente no século XXI, o mundo enfrentou os impactos devastadores de três doenças respiratórias agudas: a Síndrome Respiratória do Oriente Médio(MERS), a Síndrome Respiratória Aguda Grave (SARS) e a COVID-19, que evoluiu para uma pandemia. Essas doenças não apenas causaram um grande número de mortes, mas também prejudicaram a economia das regiões afetadas. Em particular, os países da região da América Latina e Caribe (LAC)enfrentaram desafios adicionais, devido a maiores desigualdades sociais, acesso limitado a serviços de saúde e condições de vida precárias. Portanto, é imperativo compreender os efeitos das ações de mitigação para orientar as ações no sentido de mitigar os impactos sanitários e socioeconômicos, se (ou quando)surgirem novas doenças respiratórias agudas, especialmente nestes países. Foi realizado um estudo retrospectivo para modelar a dinâmica da variação da mortalidade por COVID-19 em países da LAC e analisar sua associação com estratégias de vacinação, medidas de contenção, restrições de mobilidade e fatores socioeconômicos. A metodologia do estudo aplicou técnicas de clustering que revelaram dois agrupamentos distintos com base em características socio-demográficas, seguidos pela aplicação do XGBoost para modelar a dinâmica de variação de mortes nos países de cada cluster, ao longo do tempo. Por fim, foi aplicada a técnica de SHAP Values para compreender as associações entre mortalidade e fatores como vacinação, medidas de contenção e restrições de mobilidade. Além disso, foi realizado um painel com especialistas para avaliar a relevância e efetividade dos resultados encontrados. O estudo fornece evidências de que o suporte econômico e a conclusão do esquema de vacinação foram especialmente relevantes para reduzir a mortalidade por COVID-19.Foi possível detectar dois grupos distintos de países, onde um grupo pode ter características de maior vulnerabilidade do que o outro grupo. As intervenções mais importantes para entender a mortalidade por COVID-19 variaram em dois períodos distintos da pandemia: pré-vacinação e pós-vacinação. No período pré-vacinação, as medidas de contenção foram as intervenções mais importantes para a mortalidade nos países menos vulneráveis, enquanto para os países mais vulneráveis, foram as variações na mobilidade populacional. No período pós-vacinação, a cobertura vacinal foi a intervenção mais importante para a mortalidade nos países menos vulneráveis, enquanto os países mais vulneráveis foram mais impactados pelas medidas de contenção. / [en] In the 21st century alone, the world has faced the devastating impacts of three acute respiratory diseases: Middle East Respiratory Syndrome (MERS), Severe Acute Respiratory Syndrome (SARS), and COVID-19, which evolved into a pandemic. These diseases have not only caused a large number of deaths but have also damaged the economies of the affected regions. In particular, countries in the Latin American and Caribbean (LAC) region have faced additional challenges due to greater social inequalities, limited access to health services, and precarious living conditions. Therefore, it is imperative to understand the effects of mitigation actions to guide actions to mitigate the health and socioeconomic impacts if (or when) new acute respiratory diseases emerge, especially in these countries. A retrospective study was conducted to model the dynamics of variation in COVID-19 mortality in LAC countries and analyze its association with vaccination strategies, containment measures, mobility restrictions, and socioeconomic factors. The study methodology applied clustering techniques that revealed two distinct clusters based on sociodemographic characteristics, followed by the application of XGBoost to model the dynamics of variation in deaths in the countries of each cluster, over time. Finally, the SHAP Values technique was applied to understand the associations between mortality and factors such as vaccination, containment measures and mobility restrictions. In addition, a panel of experts was held to assess the relevance and effectiveness of the results found. The study provides evidence that economic support and the completion of the vaccination scheme were especially relevant in reducing COVID-19 mortality. It was possible to detect two distinct groups of countries, where one group may have characteristics of greater vulnerability than the other group. The most important interventions for understanding COVID-19 mortality varied in two distinct periods of the pandemic: pre-vaccination and post-vaccination. In the pre-vaccination period, containment measures were the most important interventions for mortality in the least vulnerable countries, while for the most vulnerable countries, they were variations in population mobility. In the post-vaccination period, vaccination coverage was the most important intervention for mortality in the least vulnerable countries, while the most vulnerable countries were more impacted by containment measures.

This study investigated the attitudes and perceptions of nurse managers regarding cost containment issues in selected public hospitals in the Port Elizabeth metropole of the Eastern Cape. Four hospitals participated in the study, and 211 nurse managers completed questionnaires. The results obtained from the participants’ responses indicated that: ✦ Nurse managers are ill-prepared for many responsibilities regarding cost containment, and need appropriate orientation and preparation both during their initial formal, and during their nurse management and in service training in order to fulfil their “financial” or cost containment role more effectively. ✦ Nurse managers perceived the relationship between the productivity of staff and cost containment positively, but were reportedly unable to • prevent nurses from leaving their points of duty • curb the rate of absenteeism among nurses • reduce the number of resignations ✦ Nurse managers suggested that more effective hospital cost containment efforts should ensure that • effective security checks are performed to curb losses of stock and equipment • more public telephones are installed in hospitals • stricter controls regarding wheelchairs are implemented The rationalisation of staff and services, as well as specialised equipment among the four public hospitals could enhance these hospitals’ cost containment results. However, this would necessitate reorganising these hospitals’ services at provincial level. The nurse managers required more knowledge about hospitals’ financial management and cost containment issues. Guidelines for such a course were developed addressing: analysis of monthly variance reports; budgeting for manpower; balance statement; calculations for the supplies and expenses budget; income statements; the hospital’s budgetary cycle; break-even analysis; analysis of cost-effectiveness and cost-benefit analysis. / ADVANCED NURSING SCIENCES / D.Litt. et Phil.

This thesis investigates the literature on trauma and grief in order to explore the existence of the phenomenon of traumatic grief in children. Appropriate therapies are explored for treating traumatic grief in children. The focus in this research is on non-directive art therapy as the literature has found it to be useful in traumatic circumstances. The therapeutic relationship and the focus on containment are valuable in addressing the primary need of the child in therapy especially when traumatic grief is to be addressed. A qualitative case study approach was chosen. Two case studies were selected to investigate the phenomenon of traumatic grief in children. Purposeful sampling was used to select the cases to observe the phenomenon of traumatic grief. The case studies included pre-therapy and post-therapy assessments, which included cognitive, emotional and behavioural assessments. Art therapy was found to address the problems in the two cases. / Educational Studies / M.Ed.