Prediction of Remaining Useful Life for Service-Exposed Industrial Turbine Blade

The project aims to determine the remaining useful life of service-exposed gas turbine blades by conducting an experiment to calculate the creep life. Common practice in the industries is to replace the turbine blade after its useful life has expired which is typically specified by the manufacturers. This practice is very costly and may be considered as a waste of capital if the blade can still be used. By determining the remaining useful life of a gas turbine blade, we can prolong the service life of the blade. Conducting the project will require extensive studies on the basic principle of creep deformation in metal and creep life prediction methods. Larson-Miller Parameter, which is a mean of predicting the lifetime of a material versus time and temperature using a correlative approach based on the Arrhenius rate equation, is used to extrapolate the change in rupture life with test temperature at a given stress level after the accelerated testing for creep rupture is done on the turbine blades samples. Accelerated testing needs to be done by extremely increasing the testing temperature and applied stress, thus, shortening the rupture time because the creep rate for the specimens at low temperature and stress might take a longer time frame than provided by the project time limit. A High Temperature Creep Testing Machine should be used to perform the experiment to provide reliable results and the data gathered from the experiment will be tabulated accordingly to ease the process of determining remaining useful life of the sample. Conclusion of the project will be made after the experiment data is thoroughly analyzed

A reinforcement learning formulation to the complex question answering problem

International audienceWe use extractive multi-document summarization techniques to perform complex question answering and formulate it as a reinforcement learning problem. Given a set of complex questions, a list of relevant documents per question, and the corresponding human generated summaries (i.e. answers to the questions) as training data, the reinforcement learning module iteratively learns a number of feature weights in order to facilitate the automatic generation of summaries i.e. answers to previously unseen complex questions. A reward function is used to measure the similarities between the candidate (machine generated) summary sentences and the abstract summaries. In the training stage, the learner iteratively selects the important document sentences to be included in the candidate summary, analyzes the reward function and updates the related feature weights accordingly. The final weights are used to generate summaries as answers to unseen complex questions in the testing stage. Evaluation results show the effectiveness of our system. We also incorporate user interaction into the reinforcement learner to guide the candidate summary sentence selection process. Experiments reveal the positive impact of the user interaction component on the reinforcement learning framework

L'utilisation des POMDP pour les résumés multi-documents orientés par une thématique

National audienceL’objectif principal du résumé multi-documents orienté par une thématique est de générer un résumé à partir de documents sources en réponse à une requête formulée par l’utilisateur. Cette tâche est difficile car il n’existe pas de méthode efficace pour mesurer la satisfaction de l’utilisateur. Cela introduit ainsi une incertitude dans le processus de génération de résumé. Dans cet article, nous proposons une modélisation de l’incertitude en formulant notre système de résumé comme un processus de décision markovien partiellement observables (POMDP) car dans de nombreux domaines on a montré que les POMDP permettent de gérer efficacement les incertitudes. Des expériences approfondies sur les jeux de données du banc d’essai DUC ont démontré l’efficacité de notre approche

Prediction of Remaining Useful Life for Service-Exposed Industrial Turbine Blade

The project aims to determine the remaining useful life of service-exposed gas turbine blades by conducting an experiment to calculate the creep life. Common practice in the industries is to replace the turbine blade after its useful life has expired which is typically specified by the manufacturers. This practice is very costly and may be considered as a waste of capital if the blade can still be used. By determining the remaining useful life of a gas turbine blade, we can prolong the service life of the blade. Conducting the project will require extensive studies on the basic principle of creep deformation in metal and creep life prediction methods. Larson-Miller Parameter, which is a mean of predicting the lifetime of a material versus time and temperature using a correlative approach based on the Arrhenius rate equation, is used to extrapolate the change in rupture life with test temperature at a given stress level after the accelerated testing for creep rupture is done on the turbine blades samples. Accelerated testing needs to be done by extremely increasing the testing temperature and applied stress, thus, shortening the rupture time because the creep rate for the specimens at low temperature and stress might take a longer time frame than provided by the project time limit. A High Temperature Creep Testing Machine should be used to perform the experiment to provide reliable results and the data gathered from the experiment will be tabulated accordingly to ease the process of determining remaining useful life of the sample. Conclusion of the project will be made after the experiment data is thoroughly analyzed

Improving on-farm water management by introducing wetting-front detector tools to smallholder farms in Ethiopia

Global Affairs Canad

Child labor and childhood behavioral and mental health problems in Ethiopia

Background: According to ILO estimates, at least 180 million children aged 5 to 14 years are currently engaged in fulltime work in the developing countries. However, very little information exists about childhood behavioral and mental disorders in Ethiopia. Objective: The objectives of this study are to estimate the prevalence and describe the nature of behavioral and mental health problems, as well as child abuse, nutritional problems, gross physical illness and injury among child laborers aged 8 to 15 years in Ethiopia. However, only the behavioral and mental health problems of the study population are examined here. Methods: A cross-sectional survey of children aged 8 to 15 years, and who were engaged in fulltime work in different formal and informal sectors non-laborers, was conducted in four major towns of Ethiopia. The screening instrument known as Reported Questionnaire on Children (RQC) and a diagnostic instrument known as the Diagnostic Interview for Children and Adolescents ( DICA) were used to detect symptoms and signs of behavioral and mental problems in the children. br> Results: A total of 2000 child laborers and 400 non-laborers were interviewed using RQC to screen for probable cases of behavioral and mental problems. Of these, 50% of the laborers and 42% of the non-laborers were males. The mean age of the laborers was 13.8 ±1.8 years while that of the non-laborers was 12.2 ±2.1 years. More females (76.8%) were found to have been engaged in domestic labor than males. The RQC interview screened 9.4% (n=226) of the children as probable cases of mental/ behavioral disorders, (14.0% non-laborers and 8.5% laborers). The second stage DICA interview gave an overall prevalence of 5.5% (4.9% in laborers and 8.8% in non-laborers). Conclusion: The prevalence of childhood behavioral and mental disorders in this study is within the range reported in previews studies conducted on children of the same age group. However, the lower prevalence of childhood disorders in the child laborers compared to that of the non-laborers found in the current study is probably due to selection bias or healthy workers effect. Thus, further study is recommended to explain this unexpected finding. The Ethiopian Journal of Health Development Vol. 20 (2) 2006: 119-12

Feeding hungry and thirsty soils increases yield and protects the environment: Some results of WFD experiments in LIVES

Global Affairs Canad

Improving on-farm water management by introducing wetting front detectors to small scale irrigators in Ethiopia

Smallholder irrigation to improve food security in the dry season as well as economic and demographic growth within Ethiopia is developing rapidly. However, the long term sustainability of increased irrigated production, together with degradation of soils (and associated water bodies) may be irreparably damaged by inappropriate watering schedules. In irrigation schemes, over-irrigation results in periodic water scarcity issues and in some cases sodicity. The aim of the study was to evaluate whether using wetting front detectors (WFD), a simple mechanical irrigation advice tool, would give farmers the right knowledge on when and how much to irrigate. Therefore, improving sustainable on-farm water management without negatively affecting crop and water productivity while fostering a more equitable water distribution within the scheme. The study, conducted in different regions of Ethiopia, covered various agro-ecological zones and soil conditions with over 200 farmers irrigating cereals or vegetables. Farmers and water user associations were trained on using the WFD to irrigate and distribute water within the scheme. Irrigation and crop performance was evaluated against control plots, having the same crop variety and management but traditional irrigation practices. Reduction in applied irrigation volume due to the WFD differed within and between sites due to furrow length, soil texture and farmer experience. Although yield increases were highly variable between farmers due to differences in farm management and crop variety cultivated, there was a positive effect of WFD on water productivity. Water productivity on average increased by 9 % whereas yields for the different crops increased between 13 and 17 %. In some cases the volume of water saved could double the cropped area. The reduction of irrigation events, when using the WFD, led to labour saving (up to 11 working days per ha) and fuel saving (between 50 and 150 US$ per ha). In both sites, farmers positively evaluated the scheduling tool, acknowledging that they learned to save water without negatively impacting crop productivity. The study showed that by providing access to when and how much to irrigate, farmers can positively adjust their on-farm water management resulting in more sustainable usage of their natural resources