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

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

Unpacking The Determinants Of Community Participation In Payment For Environmental Services Schemes: The Case Of The Plantation Establishment And Livelihoods Improvement Scheme In The Dundori Forest Socioecological System In Kenya

The world's forests are being rapidly degraded despite their vital importance in ecosystem services. This could be addressed through payment for environmental services (PES) that offer incentives to those involved in their conservation and management. However, there is a lack of a good understanding regarding the participation of local communities in payment for environmental service schemes in Africa. Therefore, this study undertook an analysis of factors that affect people’s participation in the payment of environmental services schemes within forest contexts in Kenya based on the case of the plantation establishment and livelihood improvement scheme. Data analysis was done using the probit regression model. The study found that various factors had a significant positive and negative relationship with the adoption of payment for environmental services. The study will inform the development and implementation of effective payment for environmental services schemes-related policies and programs. Keywords: Payment, Services, Environmental, Participation, Factors, Forest DOI: 10.7176/JRDM/95-05 Publication date: March 31st 202

The Role of Nature-Based Solutions in Building Resilience to Climate Change: An Analysis Based on the IPCC Vulnerability Framework in Kenya

Adaptation to climate change is imperative given that it continues to pose severe and escalating risks to humanity and the ecological systems on which it depends. This calls for Nature-based solutions in climate adaptation since they involve the sustainable management and restoration of ecosystems while improving human livelihoods. However, despite their importance, the potential of Nature-based solutions in building resilience to climate change has not been rigorously studied. Also, no studies have done a joint analysis of the effect of Nature-based solutions on the three dimensions of vulnerability to climate change (exposure, sensitivity, and adaptive capacity. This study thus aimed to undertake a joint analysis of the role of nature-based solutions in building resilience to climate change based on its influence on the three dimensions of vulnerability. Data analysis was done using the multivariate analysis of variance (MANOVA). The study’s multivariate and univariate tests found that nature-based climate solutions influenced the three dimensions of climate change vulnerability (Exposure, sensitivity, and adaptive capacity). The three dimensions of vulnerability were also found to be interconnected and have various relationships between them. The study will help understand how nature-based solutions build resilience to climate change and inform their design and implementatio

Socio-economic Factors Affecting Adoption of Agroforestry Practices in Forest Adjacent Communities: The Case of Ndabibi Location, Nakuru County, Kenya

Agroforestry greatly helps to improve production by creating the right conditions for other components of the production system and also creates other income streams and benefits. Agroforestry also creates an alternative source of forest derived products and thus help reduce forest destruction. The development of agroforestry in Africa has not been very successful due to poor understanding of the underlying socio-economic factors underpinning the adoption in specific local contexts, including adjacent forest communities. This hinders proper decision making hence ineffective management of agroforestry practices. This is especially the case for Ndabibi Location an area marked by low farm production including degradation of the adjacent Eburru Forest. This study, therefore, aimed to analyze the socio-economic factors affecting agroforestry adoption in Ndabibi Location, a forest adjacent community. This study used a descriptive study design and systematic sampling design. The study used primary and secondary data where primary data was collected using a household questionnaire survey, focus group discussions, key informant interviews and observations. The study found socio-economic factors either have positive or negative relationships with agroforestry adoption. The factors that have a positive relationship with agroforestry practice include age, household size, formal education level, contact with extension services, membership to community-based associations and income levels. Gender, land size and forest dependency were found to have a negative relationship with the adoption of agroforestry practice. Understanding of the socio-economic factors underlying and thus affecting adoption of agroforestry adoption in Ndabibi Location will help communities, policymakers and practitioners to make the right planning and management decisions towards the promotion of agroforestry practice in forest adjacent communities. This shall increase the production, livelihoods and income sources diversification hence leading to the sustainable management of forest ecosystems

Pressed for Space: The Effects of Justification and the Printing Process on Fifteenth-Century Orthography

There is a long-held belief that, prior to the standardisation of written English, printers altered spellings to justify their type. I investigate this claim through an analysis of spelling changes in William Caxton’s two editions of the Canterbury Tales—by examining text within one book, written by one author, and set by one compositor, the only difference between the sections of verse and the sections of prose should be the requirement for justification within the latter. Were the compositors altering spellings to justify their type, we would expect to see a greater number of altered spellings in the prose sections of text. This is not what the results of this study show—instead there is no statistically significant difference between the frequency of spelling changes in justified and non-justified text. However, there is a significantly higher number of abbreviations introduced into the justified text. These results suggest that the compositor of Caxton’s second edition Canterbury Tales did not change spellings to justify his type

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

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

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