Experimental study of rotor unsteady airloads due to blade-vortex interaction

Measurements of unsteady, rotary wing air loads and time derivatives for rotor blade intersecting completely rolled up vorte

Effect of Wing Tip Configuration on the Strength and Position of a Rolled-Up Vortex

Effect of wing tip configuration on strength and position of rolled-up vorte

Analysis of model rotor blade pressures during parallel interaction with twin vortices

This paper presents and provides analysis of unsteady surface pressures measured on a model rotor blade as the blade experienced near parallel blade vortex interaction with a twin vortex system. To provide a basis for analysis, the vortex system was characterized by hot-wire measurements made in the interaction plane but in the absence of the rotor. The unsteady pressure response resulting from a single vortex interaction is then presented to provide a frame of reference for the twin vortex results. A series of twin vortex interaction cases are then presented and analyzed. It is shown that the unsteady blade pressures and forces are very sensitive to the inclination angle and separation distance of the vortex pair. When the vortex cores lie almost parallel to the blade chord, the interaction is characterized by a two-stage response associated with the sequential passage of the two cores. Conversely, when the cores lie on a plane that is almost perpendicular to the blade chord, the response is similar to that of a single vortex interaction. In all cases, the normal force response is consistent with the distribution of vertical velocity in the flow field of the vortex system. The pitching moment response, on the other hand, depends on the localized suction associated with the vortex cores as they traverse the blade chord

Development of a home literacy environment questionnaire for Tamil-speaking kindergarten children

Abstract Background The development of emergent literacy skills depends upon the literacy environments and experiences of children at home. Children’s home literacy environment is closely related to the development of various aspects of emergent literacy like letter knowledge, phonological awareness, and vocabulary. Dimensions of home literacy environment, such as physical (literacy) environment, child’s own literacy habits, parental literacy habits, parent-child interaction for language and literacy activities, and parental beliefs about literacy, have been reported in literature. Methods The present study describes the construction of a home literacy environment questionnaire for Tamil-speaking kindergarten children in the Indian context. The various dimensions of home literacy environment were described, and items related to each dimension were listed. Seventeen judges rated each item on a five-point Likert scale ranging from 0 (no fit) to 4 (excellent fit). Their comments/remarks/opinion, specific to an item or dimension, were also taken. The rating responses were analyzed for content validity and internal consistency. Results Content validity index was calculated at item level as well as scale level. The items in each subscale/dimension which had the item level content validity index scores higher than 0.78 were included in the final questionnaire and the other items were rejected. The scale level content validity index scores were higher than 0.90, indicating good content validity. Cronbach’s alpha was calculated as a measure of internal consistency. Cronbach’s alpha values were lower than 0.7 for three domains: physical environment, parent literacy habits, and parental beliefs. Conclusions The questionnaire developed promises to be a useful tool to evaluate the home literacy environment of Tamil children who undergo formal education in English medium schools like in India. The questionnaire developed and presented here can help in collecting reliable data to make informed decisions about children’s (whether typically developing or with developmental disabilities) home literacy environment

Introduction: Reading and writing in semi-syllabic scripts

Overview of special issue.This article is an overview of studies in a special issue of the journal, focused on reading and writing in semi-syllabic scripts

Cortical network for reading linear words in an alphasyllabary

Functional imaging studies have established cortical networks for reading alphabetic, syllabic and logographic scripts. There is little information about the different cortical areas that participate in reading an alphasyllabary. We use functional brain imaging to study the reading network for Devanagari, an alphasyllabary. Similar to syllabic scripts, the basic phonological unit that corresponds to a grapheme in Devanagari, called an akshara, is a syllable but the component consonant and vowel within akshara can always be visually analyzed giving it the appearance of an alphabetic system. Unlike an alphabetic system wherein arrangement of consonants and vowels is linear, in Devanagari, vowels can also be placed linearly in a sequential manner or non-linearly, above or below, making it visuospatially complex. In this study we used functional neuroimaging to ascertain the cortical reading network when 10 native speakers of Hindi, read linear words in Devanagari. Akin to other word reading studies, we find activation in the mid-fusiform gyrus (visual word form area, BA 37). Region of interest analysis shows involvement of left superior temporal gyrus (BA 41), inferior (BA 40) and superior parietal (BA 7) lobules. These findings suggest that the reading network for Devanagari, an alphasyllabary encompasses cortical areas involved in reading both alphabetic and syllabic writing systems

Cognitive Assessment System (CAS): A review

This paper presents a review of literature of cognitive Assessment system (CAS) developed by J. P. Das and Jack A. Naglieri in1997 following their PASS theory (Planning, Attention, Successive & Simultaneous) based on Luria�s model of neuropsychological processing. CAS is a reliable measure of cognitive functioning which has proved its validity across cultures. CAS is acquiring professional status in assessment of multiple as well as specific neuropsychological processing over the past 27 years. The battery has also resulted in remedial tests such as PREP (PASS Remedial Enhancement Program). This paper traces the CAS through important research papers published in various international journals and books between 1983 and 2012