RELIABILITY-BASED MAINTENANCE STRATEGY FOR A MILITARY WEAPON SYSTEM – A CASE STUDY

Military Weapons Systems are currently facing increasing use in a worldwide intensification of military conflicts, leading to various changes to improve and solve problems in logistics operations. The main objective of this paper is to use RCM (Reliability Centered Maintenance) and FMECA (Failure Modes, Effects, and Criticality Analysis) methodology applied to this High-Tech Weapon System to identify the need for spare parts by improving the current maintenance plan. A functional analysis was performed. Then, functional failures, failure modes, and effects are defined. This methodology manages the identified risks, knowing which components have a high failure rate, improving maintenance plans, and identifying the need for spare parts at the earliest possible stage. Thus, the study was supported by “ReliaSoft RCM++” software that facilitates the RCM analysis approach. This software supports all major RCM industry standards such as ATA, MSG-3, MIL-STD-1629A, SAE JA1011, and SAE JA1012 and provides complete capabilities for FMECA. This study aims to identify the systems, subsystems, and components that frequently fail, ensuring operational capability and corrective actions to improve the weapon system’s plans, maintenance schedules, and availability. This technique is powerful as decision support to the Military Logistics Command because it identifies the need for spare parts as early as possible

O papel mediador da dor psicológica na relação entre trauma infantil e ideação suicida em indivíduos com perturbação de uso de substâncias

O objetivo desta investigação, descritiva correlacional e transversalmente operacionalizada, foi estudar os efeitos de mediação da dor psicológica e da tolerância à dor psicológica na relação entre trauma infantil e ideação suicida, em indivíduos com perturbação de uso de substâncias. Esperava-se que esta associação fosse mediada por níveis elevados de dor psicológica e níveis baixos de tolerância à dor psicológica. Participou uma amostra de 102 adultos com perturbação de uso de substâncias. Utilizou-se path analysis por modelação de equações estruturais para testar dois modelos de mediação. Verificou-se que sintomas depressivos e níveis baixos de managing the pain mediaram totalmente a relação entre trauma infantil e ideação suicida. Contrariamente ao esperado, a dor psicológica não se apresentou como variável mediadora. Os resultados sugerem que os sintomas depressivos e a menor capacidade de gerir a dor psicológica contribuem para explicar o porquê de experiências traumáticas na infância poderem resultar em cognições suicidas; The mediating role of psychological pain in the relationship between childhood trauma and suicidal ideation in individuals with a substance use disorder Abstract: The aim of this research, of a descriptive correlational nature and cross-sectionally operationalized, was to study the mediating effects of psychological pain and tolerance for psychological pain in the relationship between childhood trauma and suicidal ideation, in individuals with a substance use disorder. We expected such association would be mediated by high levels of psychological pain and low levels of tolerance for psychological pain. A sample of 102 adults with a substance use disorder participated in the study. Path analysis by structural equation modeling was used to test two mediation models. It was found that depressive symptoms and low levels of managing the pain fully mediated the relationship between childhood trauma and suicidal ideation. Contrary to expectations, psychological pain did not act as a mediating variable. Findings suggest that depressive symptoms and lower ability to manage psychological pain contribute towards explaining why traumatic childhood experiences may result in suicidal cognitions

Evolution of the temporal structure of world high competition judo combat (2013 a 2017)

[EN] Judo is a sport that is constantly evolving. Rule modifications and changes in tactical strategies have enhanced scoring opportunities and reduced penalties. This study analyzed the evolution of the temporal structure of combat through an assessment of the total match time (TMT), time engaged in combat (CT), time without (TWOG) and with grip (TWG), pause time (PT), the percentage of combat time in tachi-waza and combat in ne-waza, and the frequency of combat/tactical/technical actions/tasks. Data were descriptively analyzed overtime during the 2013, 2014, 2015, and 2017 World Championships and the 2016 Olympic Games. Data from 3,084 male and female matches across weight and gender categories were collapsed and used to compare the TMT, CT, TWOG, TWG, PT, and frequency of tactical actions over time and by competition phase (i.e., qualifiers, quarterfinals, recaps, semi-finals, bronze and finals). There were several temporal changes that occurred due to the rules modifications. The TMT increased by 3.6% over the sampling period for all competition phases. Regarding the duration of combat activities, relative to TMT: 25% was spent in PT (M PT = 8.9 s); 36% (M TWG = 9.6 s) was spent in TWG; 25% (M = 7.3 s) was spent in TWOG; 15% was spent in ne-waza(M = 7.7 s per action). With the changes of the rules in 2017, there was a Golden Point Score increase of 25% in the total number of combat; in relation to the competition phase, there was a 50% increase in the total number of combat activities. There was also a 15% increase in the number of actions in the competition final phase. There was some variation of the time structure of the combat, namely in the total time of the fighting and Golden Point, as a consequence of the change of the Referee rule changes

Modelling groundwater-surface water interactions in the Sines aquifer system (Southwest of Portugal)

The Sines aquifer system, with an area of approximately 250 km2, located on the southwest coast of Portugal, is a multi-aquifer system consisting in a lower artesian karst aquifer supported by carbonate formations of the Jurassic, and a top detritic phreatic aquifer which lies in marine Miocene and Plio-Pleistocene formations. A numerical flow model for this aquifer system has already been developed previous to this study. However, the estimates of water transfers between the top detritic aquifer system and the stream network have not been validated and calibrated, due to insufficient monitoring to allow real data to be compared with the model simulations. Answering this issue, a monitoring plan was implemented, in the context of research project Groundscene, to continuously register hydraulic head and stream discharges data, in order to produce estimates of groundwater contributions from the top detritic aquifer to the stream network, allowing the calibration of the numerical flow model developed for the top detritic Sines aquifer system. The proposed model allowed the simulations of groundwater contributions in different scenarios of prospective exploitation and climate change, being useful as a forecast tool to support decision making regarding groundwater exploitation for human consumption while protecting groundwater dependent ecosystems

Sistema dinâmico de microprodução fotovoltaica de elevado rendimento

Mestrado em Engenharia de Automação IndustrialA presente dissertação foca-se em sistemas de microprodução fotovoltaicos e numa possibilidade de aumentar a sua produção. Neste tipo de sistemas os painéis solares são o elemento principal, que permitem converter a energia solar em energia eléctrica, mas esta conversão é feita com uma eficiência baixa, da ordem dos 15%. Para que seja possível a conversão é necessário que as células sejam submetidas a luz solar, quanto maior for a quantidade de luz incidente maior será o valor de energia convertido. Devido ao movimento de rotação e translação da terra, a posição relativa do sol vai-se alterando ao longo do dia e do ano. As variações de luz solar ao longo do dia, fazem com que a produção do sistema fotovoltaico também varie. Os sistemas de microprodução fotovoltaica em Portugal estão sujeitos a determinadas leis, uma das quais limita a potência máxima que o sistema pode debitar. Nesta situação o sistema de microprodução irá debitar a sua potência máxima no meio do dia, onde a luz solar é mais intensa, sendo que no restante tempo o sistema irá produzir uma potência inferior à limite. É o objectivo desta tese desenvolver um sistema para melhorar o aproveitamento das horas em que a luz solar disponível não permite produzir a potência máxima. A abordagem tomada parte pelo sobredimensionamento do sistema de produção fotovoltaico e desenvolvimento de um sistema de controlo. O sistema de controlo será responsável por regular a potência produzida ao longo do dia, e assegurar-se de que esta nunca excede o limite. Pretende-se desenvolver um protótipo para controlo da potência produzida e a sua análise, a fim de verificar os ganhos obtidos com esta abordagem para aumentar a produção de um sistema fotovoltaico.This thesis is focused in photovoltaic micro production systems and the possibility of improving its efficiency. In this kind of systems the solar panels are the main element, because they allow the conversion of sun light into electrical energy, but with low efficiency around 15%. To start the conversion it is required that the solar cells receive sun light, increased light will also increase the production. Because of the earth’s rotation and translation movements, the sun position changes along the day and year. The sun light changes make the photovoltaic production to change as well. The photovoltaic micro production systems in Portugal are subject to laws, one of them limits the maximum power production. In this case the system will produce its maximum power at around mid-day, where the sun light is stronger, during the rest of the day the production will be lower than the limit because of the weaker sun light. It is the purpose of this thesis to develop a system that makes better use of the sun light when it is not enough to produce the maximum power. The approach taken requires over dimensioning the photovoltaic system and the development of a controlling system. The control system will take part in regulating the production along the day, avoiding the production to exceed the power limit. A prototype of the production control system is to be study and developed, in order to check the benefits of this this kind of approach to increase efficiency in photovoltaic micro production systems

Hidden archives, hidden practices: debats about music-making: abstracts

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XXXV Congress of the International Association of Hydrogeologists, Groundwater and Ecosystems – Abstract Book

Resumos das comunicações do XXXV Congresso da Associação Internacional de Hidrogeólogos (IAH

Análise dos Estados de Atenção Visual e Auditiva com Base na Análise de Electroencefalogramas

Os electroencefalogramas são actualmente uma técnica médica, não invasiva e pouco dispensiosa, que mede a função do cérebro através da monitorização da actividade eléctrica gerada pelas estruturas cerebrais. A descoberta dos padrões resultantes desta actividade irá permitir determinar a ocorrência de certos estados mentais e por conseguinte: diagnosticar algumas anomalias, tratar certas patologias e mesmo interagir com dispositivos sem a utilização do sistema nervoso periférico - os mecanismos computador-cérebro. As técnicas de processamento dos electroencefalogramas são, contudo, complexas. Os padrões obtidos nos registos variam com o sujeito e o seu estado de espírito, e podem ser afectados por diversos tipos de perturbações, como por exemplo movimentos oculares. Neste âmbito, este relatório irá abordar, com base em técnicas de análise e processamento de electroencefalogramas, a detecção da abertura ou fecho de olhos em sujeitos com o sentido da visão dentro dos parâmetros normais, e da ocorrência de sons que sobressaiem no ambiente que envolve sujeitos, como é o caso por exemplo do ruído de um avião. Ambos os problemas em estudo são relevantes, uma vez que permitem de uma forma preliminar analisar os estados de atenção visual e auditiva do utilizador. O trabalho descrito integra-se num objectivo de investigação mais vasto, na qual se pretende utilizar técnicas de análise e processamento de electroencefalogramas na avaliação da usabilidade de interfaces. O trabalho desenvolvido envolveu a realização de experiências específicas, com sujeitos distintos, utilizando um sistema de mapeamento electroencefalográfico com 16 electródos. Os dados obtidos foram processados utilizando algoritmos desenvolvidos em MatLab 6.5 [1] e 2

Development of Neurogenic Detrusor Overactivity after Thoracic Spinal Cord Injury Is Accompanied by Time-Dependent Changes in Lumbosacral Expression of Axonal Growth Regulators

Thoracic spinal cord injury (SCI) results in urinary dysfunction, which majorly affects the quality of life of SCI patients. Abnormal sprouting of lumbosacral bladder afferents plays a crucial role in this condition. Underlying mechanisms may include changes in expression of regulators of axonal growth, including chondroitin sulphate proteoglycans (CSPGs), myelin-associated inhibitors (MAIs) and repulsive guidance molecules, known to be upregulated at the injury site post SCI. Here, we confirmed lumbosacral upregulation of the growth-associated protein GAP43 in SCI animals with bladder dysfunction, indicating the occurrence of axonal sprouting. Neurocan and Phosphacan (CSPGs), as well as Nogo-A (MAI), at the same spinal segments were upregulated 7 days post injury (dpi) but returned to baseline values 28 dpi. In turn, qPCR analysis of the mRNA levels for receptors of those repulsive molecules in dorsal root ganglia (DRG) neurons showed a time-dependent decrease in receptor expression. In vitro assays with DRG neurons from SCI rats demonstrated that exposure to high levels of NGF downregulated the expression of some, but not all, receptors for those regulators of axonal growth. The present results, therefore, show significant molecular changes at the lumbosacral cord and DRGs after thoracic lesion, likely critically involved in neuroplastic events leading to urinary impairment