A framework development to predict remaining useful life of a gas turbine mechanical component

Power-by-the-hour is a performance based offering for delivering outstanding service to operators of civil aviation aircraft. Operators need to guarantee to minimise downtime, reduce service cost and ensure value for money which requires an innovative advanced technology for predictive maintenance. Predictability, availability and reliability of the engine offers better service for operators, and the need to estimate the expected component failure prior to failure occurrence requires a proactive approach to predict the remaining useful life of components within an assembly. This research offers a framework for component remaining useful life prediction using assembly level data. The thesis presents a critical analysis on literature identifying the Weibull method, statistical technique and data-driven methodology relating to remaining useful life prediction, which are used in this research. The AS-IS practice captures relevant information based on the investigation conducted in the aerospace industry. The analysis of maintenance cycles relates to the examination of high-level events for engine availability, whereby more communications with industry showcase a through-life performance timeline visualisation. Overhaul sequence and activities are presented to gain insights of the timeline visualisation. The thesis covers the framework development and application to gas turbine single stage assembly, repair and replacement of components in single stage assembly, and multiple stage assembly. The framework is demonstrated in aerospace engines and power generation engines. The framework developed enables and supports domain experts to quickly respond to, and prepare for maintenance and on-time delivery of spare parts. The results of the framework show the probability of failure based on a pair of error values using the corresponding Scale and Shape parameters. The probability of failure is transformed into the remaining useful life depicting a typical Weibull distribution. The resulting Weibull curves developed with three scenarios of the case shows there are components renewals, therefore, the remaining useful life of the components are established. The framework is validated and verified through a case study with three scenarios and also through expert judgement

DSP phase angle controlled three phase to single phase uninterruptible power supply

Includes bibliographical references

Overview of Remaining Useful Life prediction techniques in Through-life Engineering Services

Through-life Engineering Services (TES) are essential in the manufacture and servicing of complex engineering products. TES improves support services by providing prognosis of run-to-failure and time-to-failure on-demand data for better decision making. The concept of Remaining Useful Life (RUL) is utilised to predict life-span of components (of a service system) with the purpose of minimising catastrophic failure events in both manufacturing and service sectors. The purpose of this paper is to identify failure mechanisms and emphasise the failure events prediction approaches that can effectively reduce uncertainties. It will demonstrate the classification of techniques used in RUL prediction for optimisation of products’ future use based on current products in-service with regards to predictability, availability and reliability. It presents a mapping of degradation mechanisms against techniques for knowledge acquisition with the objective of presenting to designers and manufacturers ways to improve the life-span of components

Development of an ontology for aerospace engine components degradation in service

This paper presents the development of an ontology for component service degradation. In this paper, degradation mechanisms in gas turbine metallic components are used for a case study to explain how a taxonomy within an ontology can be validated. The validation method used in this paper uses an iterative process and sanity checks. Data extracted from on-demand textual information are filtered and grouped into classes of degradation mechanisms. Various concepts are systematically and hierarchically arranged for use in the service maintenance ontology. The allocation of the mechanisms to the AS-IS ontology presents a robust data collection hub. Data integrity is guaranteed when the TO-BE ontology is introduced to analyse processes relative to various failure events. The initial evaluation reveals improvement in the performance of the TO-BE domain ontology based on iterations and updates with recognised mechanisms. The information extracted and collected is required to improve service k nowledge and performance feedback which are important for service engineers. Existing research areas such as natural language processing, knowledge management, and information extraction were also examined

Religious values in an age of globalization and development in Nigeria

This write-up attempts to review the role of Christian Religion Studies and values in an age of globalization and development. This is because the world is undergoing a turbulent experience of war, civil unrest, national and international conflict and crises situation. Using the expository and deductive reasoning, the paper has found out that only religion and particularly Christian Religious Studies and education can use the values in its kit to overcome these challenges. These can be done through the framework of dialogue, respect for the plurality of religious faiths and good leadership. It provides a theoretical framework of the concepts of religion and globalization. It examines how Christian religious values become global and identifies the common Christian values and using such as indexes of globalization and development. It finally draws conclusion

Morphological alterations in the seminiferous tubules of adult Wistar rats: the effects of prenatal ethanol exposure

This study presents the effects of prenatal ethanol exposure on the morphology of the seminiferous tubules of the testes in the adult male rat. Timed-pregnant adult female Wistar rats (average weight 200 g) were given daily intragastric intubation of 5.8 g/kg ethanol between gestation days 9 and 12. Pair-fed and ad lib-fed animals served as controls. The pups were weighed at birth and weaned at 30 days. At 42 days of age the male offspring (n = 10) from each group were anaesthetised and the testes removed and weighed. Another set of male rats from each group (n = 6), were anaesthetised, whole body perfused and the testes removed and processed for paraffin embedding. Sections were subjected to morphological analysis and morphometric measurements based on computerised techniques following haematoxylin and eosin, PAS and reticulin staining. The results demonstrated that prenatal ethanol exposure induced persistent growth retardation and a 66% reduction in testicular weight and severely altered the morphology of the seminiferous tubules of adult male rats, causing a reduction in the cross-sectional area of the tubules by 18%, germinal epithelium thickness by 21% (p < 0.001) and an inhibition of spermatogenesis. The study showed the absence of reticulin fibres in the peritubular tissue of seminiferous tubules of prenatal ethanol-exposed adult male rats. The results imply that damage following prenatal ethanol exposure occurs irreversibly in utero and persists into adulthood in the exposed animals, which may have implications for male fertility

Service Knowledge Capture and Reuse

The keynote will start with the need for service knowledge capture and reuse for industrial product-service systems. A novel approach to capture the service damage knowledge about individual component will be presented with experimental results. The technique uses active thermography and image processing approaches for the assessment. The paper will also give an overview of other non-destructive inspection techniques for service damage assessment. A robotic system will be described to automate the damage image capture. The keynote will then propose ways to reuse the knowledge to predict remaining life of the component and feedback to design and manufacturing

The Role Of Competitive Strategies On Performance Of Kenya State Corporations

Competitive strategies are important determinant of performance of State Corporations in Kenya. The main objective of the study was to determine the role of organizational autonomy and strategic positioning in the relationship between competitive strategies and performance of Kenyan State Corporations. This study was guided by positivist philosophy. The study adopted a descriptive cross-sectional census survey on a population of 187 Kenyan state corporations across the public sector. The study used both primary and secondary data. Primary data was collected by questionnaires which were administered to the Chief Executive Officers of the State Corporations. Data analysis entailed both descriptive and inferential statistics. The results indicated moderate mean score for cost leadership an indication that cost leadership was rated by the respondents as being inadequate for the Kenyan State Corporations. The corporations that emphasized efficiency had the highest mean score followed by the organizations emphasizing on time management. The study concluded that competitive strategies had a great influence on performance

"Prologue". Eneydos

Dialecto literario. -- Inglés del norte. -- Inglés del sur. -- Pertenece a la colección LD 1500-1700 del Salamanca Corpus. -- Prosa. -- William Caxton. -- Prologue. Eneydos. -- 1490.[ES]Uno de los primeros comentarios sobre la variación regional en Inglaterra. [EN]One of the first remarks on regional variation in England

Chronic Treatment with Ethanolic Extract of the Leavesof Azadirachta indica Ameliorates Lesions of Pancreatic Islets in Streptozotocin Diabetes

Botanical drugs are complementary therapies in the management of diabetes mellitus. In this work, we studied the effects of chronic treatment of diabetic rats with A. indica (neem) on blood glucose, pancreatic islet histopathology, and oxidative status of the pancreas. Fifty-four Wistar rats (5-8 weeks old) were randomly assigned to 5 treatment groups. Hyperglycemia was induced in 34 fasted rats with a single i.p. injection of STZ (70 mg/kg bw/d). Ethanolic extract of A. indica leaves (500 mg/kg bw/d) was given orally to diabetic rats (n=12) for 50d. Glibenclamide was given (p.o) at 600 µg/ kg bw/d. In each group, blood glucose, islet histopathology, and pancreatic oxidative status, were assessed. All hyperglycemic rats in the neem-treated group had become normoglycemic at the end of week 2. By 50d, the number of viable b cells was highest in the neem-treated diabetic rats (compared with the diabetic and glibenclamide groups). Similarly, islet histology showed marked improvement in this group, in addition to improved oxidative stress. Our findings confirmed the hypoglycemic effect of neem. Besides, the improved islet morphology and oxidative status in neem-treated diabetic rats suggest the potential of this herb at improving lesions of the pancreatic islet in diabetes mellitus. Los medicamentos a base de plantas son terapias complementarias en el manejo de la diabetes mellitus. En este trabajo se estudiaron los efectos del tratamiento crónico de ratas diabéticas con A. indica (Neem) sobre la glucosa de la sangre, la histopatología de los islotes pancreáticos, y el estado oxidativo del páncreas. Cincuenta y cuatro ratas Wistar (5-8 semanas de edad) fueron asignadas aleatoriamente a 5 grupos de tratamiento. La hiperglucemia fue inducida en 34 ratas en ayunas con una única inyección IP de STZ (70 mg/kg peso corporal/d). El extracto etanólico de hojas de A. indica (500 mg/kg de peso corporal/día) fue administrado por vía oral a ratas diabéticas (n=12) por 50d. Glibenclamida fue dada (PO) a 600 mg/kg peso corporal/d. En cada grupo, la glucosa en la sangre, la histopatología de los islotes, y el estado oxidativo de páncreas, se evaluaron. Todas las ratas de hiperglucemia en el grupo tratado con el Neem se habían convertido en normoglucémicas al final de la semana 2. Por 50d, el número de células b viables fue mayor en el Neem ratas tratadas con diabetes (en comparación con los grupos de diabéticos y glibenclamida). Del mismo modo, la histología de los islotes mostró una notable mejoría en este grupo, además de mejorar el estrés oxidativo. Nuestros resultados confirman el efecto hipoglucemiante de Neem. Además, la mejora de la morfología de los islotes y el estado de oxidación en el neem tratados con ratas diabéticas sugieren el potencial de esta hierba en la mejora de las lesiones de los islotes pancreáticos en la diabetes mellitus