Flutter of Darrieus wind turbine blades: Correlation of theory and experiment

Flutter analysis of two wind turbines was correlated with experimental data for flutter of Darrieus blades

Flutter of Darrieus wind turbine blades

The testing of Darrieus wind turbines has indicated that under certain conditions, serious vibrations of the blades can occur, involving flatwise bending, torsion, and chordwise bending. A theoretical method of predicting the aeroelastic stability of the coupled bending and torsional motion of such blades with a view to determining the cause of these vibrations, and a means of suppressing them was developed

A model-based framework for classifying and diagnosing usability problems

A great deal of study has been devoted to the problem of how to identify and categorize usability problems; however, there is still a lack of studies dealing with the problem of how to diagnose the causes of usability problems and how to feed them back into design process. The value of classifying usability problems can be enhanced when they are interpreted in connection with design process and activities. Thus, it is necessary to develop a systematic way of diagnosing usability problems in terms of design aspects and applying diagnosis results to improve design process and activities. With this issue in mind, this paper proposes a conceptual framework that supports a systematic classification and diagnosis of usability problems. This paper firstly reviews seven approaches to classifying usability problems. Then, we point out the needs of adopting a model-based approach to classifying and diagnosing usability problems and of developing a comprehensive framework guiding the use of model-based approaches. We then propose a conceptual framework that specifies how a model-based classification and diagnosis of usability problems should be conducted and suggests the combined use of three different types of models, each of which addresses context of use, design knowledge and design activities. Last, we explain how a sound classification scheme of usability problems can be systematically developed, and how the classification of usability problems can be connected to design process and activities on the basis of the framework

Modelling work domain knowledge with the combined use of abstraction hierarchy and living systems theory

This study is aimed at developing a new method for modelling work domain knowledge with the combined use of abstraction hierarchy (AH) and living systems theory (LST). AH has been widely used as a work domain knowledge representation framework in the field of cognitive systems engineering and human–computer interaction, and its usefulness has been proved in a range of work domains. However, its effective use still remains a challenging issue. In order to address this problem, this study firstly points out several issues that can be raised in the use of AH and then explains why and how LST can give concepts and principles helpful to resolve them. The proposed method offers a framework for how to combine AH and LST, particularly to identify functional knowledge at higher abstraction levels. It also offers a process for modelling the knowledge of a work domain based on the combined use of AH and LST. The use of the proposed method is exemplified by modelling the knowledge of a simplified secondary cooling system of nuclear power plants. The proposed method is a new approach to refining the concepts of AH and modelling the knowledge of a work domain that humans should interact. It is believed that it will be a useful tool for knowledge modellers in identifying and modelling the knowledge of a work domain in terms of its functional structure. However, it should be noted that its usefulness can be limited to technology-oriented engineering systems; it would not be easily applied to human activity-oriented systems

The photoelectron spectra of the diazanaphthalenes

The high-resolution He 584 Å photoelectron spectra of ten diazanaphthalenes are presented. The ordering of the π orbitals and the nitrogen “lone-pair” orbitals is discussed. Several semi-empirical quantum-chemical calculation methods have been screened against the experimental evidence

Perfluoro effect in the photoelectron spectra of quinoline and isoquinoline

The high-resolution He 584Aophotoelectron spectra of heptafluoroquinoline and heptafluoroisoquinoline are compared with those of the parent compounds. Shifts in π ionisation potentials, due to the fluorine substitution, can be described with an inductive and a combined inductive-conjugative Hu¨ckel model

Use of a big data analysis technique for extracting HRA data from event investigation reports based on the Safety-II concept

The safe operation of complex socio-technical systems including NPPs (Nuclear Power Plants) is a determinant for ensuring their sustainability. From this concern, it should be emphasized that a large portion of safety significant events were directly and/or indirectly caused by human errors. This means that the role of an HRA (Human Reliability Analysis) is critical because one of its applications is to systematically distinguish error-prone tasks triggering safety significant events. To this end, it is very important for HRA practitioners to access diverse HRA data which are helpful for understanding how and why human errors have occurred. In this study, a novel approach is suggested based on the Safety-II concept, which allows us to collect HRA data by considering failure and success cases in parallel. In addition, since huge amount of information can be gathered if the failure and success cases are simultaneously involved, a big data analysis technique called the CART (Classification And Regression Tree) is applied to deal with this problem. As a result, it seems that the novel approach proposed by combining the Safety-II concept with the CART technique is useful because HRA practitioners are able to get HRA data with respect to diverse task contexts

The Effect of Medicaid Expansions for Low-Income Children on Medicaid Participation and Insurance Coverage: Evidence from the SIPP

Increased availability of public health insurance for children has led to two potentially contradictory concerns for public policy: that expanded availability of public insurance may lead families to decline private insurance and that additional public coverage may not reach many uninsured children. We examine these two concerns using data from the 1987-1993 Surveys of Income and Program Participation. Using static models we find that the expansions resulted in increased Medicaid coverage, although the estimates of take-up are smaller than estimates from previous research. We find little evidence of a negative relationship of any significant magnitude between eligibility for Medicaid and private coverage. We also find that children who have been eligible for Medicaid longer are more likely to be enrolled in Medicaid but no more likely to have lost private coverage. Including individual fixed effects reduces the magnitude of the estimated take-up effect, while the fixed effects estimates for the private insurance regression become negative and marginally statistically significant in some specifications. Simple dynamic models of insurance choice show that insurance choice is quite persistent. The estimated long run impact of eligibility in the dynamic models is larger than the estimate from the static models, while the immediate impact of expanded Medicaid eligibility from the dynamic models is smaller than the estimated effect from the static models.