7,473 research outputs found
Digital control of the Kuiper Airborne Observatory telescope
The feasibility of using a digital controller to stabilize a telescope mounted in an airplane is investigated. The telescope is a 30 in. infrared telescope mounted aboard a NASA C-141 aircraft known as the Kuiper Airborne Observatory. Current efforts to refurbish the 14-year-old compensation system have led to considering a digital controller. A typical digital controller is modeled and added into the telescope system model. This model is simulated on a computer to generate the Bode plots and time responses which determine system stability and performance parameters. Important aspects of digital control system hardware are discussed. A summary of the findings shows that a digital control system would result in satisfactory telescope performance
The Effect of Zonally Asymmetric Ozone Heating on the Northern Hemisphere Winter Polar Stratosphere
[1] Previous modeling studies have found significant differences in winter extratropical stratospheric temperatures depending on the presence or absence of zonally asymmetric ozone heating (ZAOH), yet the physical mechanism causing these differences has not been fully explained. The present study describes the effect of ZAOH on the dynamics of the Northern Hemisphere extratropical stratosphere using an ensemble of free-running atmospheric general circulation model simulations over the 1 December - 31 March period. We find that the simulations including ZAOH produce a significantly warmer and weaker stratospheric polar vortex in mid-February due to more frequent major stratospheric sudden warmings compared to the simulations using only zonal mean ozone heating. This is due to regions of enhanced Eliassen-Palm flux convergence found in the region between 40°N–70°N latitude and 10–0.05 hPa. These results are consistent with changes in the propagation of planetary waves in the presence of ZAOH predicted by an ozone-modified refractive index
Boys and girls come out to play: Gender differences in children\u27s play patterns
This paper presents findings from The Irish Neighbourhood Play Study; a national, cross-border research project which recorded children’s play patterns in Ireland during 2012. The study incorporated 1688 families across 240 communities. This study recorded the play patterns of children in Ireland aged birth-14 years. The findings of the study are discussed here in the context of gendered patterns. Particular emphasis is placed on the skill differences developed through various play choices. These differences are explored within the context of established literature on the learning strengths of boys and girls. Established bodies of literature on children’s learning across gender lines has long been engaged in the debate about whether these differences are biological or socially constructed. This paper offers a parallel question; Are gender differences within learning, constructed through play choices within childhood?
©IATED (2017). Reproduced in Research Online with permission
The age of imagination: imagining play and invention: implications for creative development
This paper presents findings from The Irish Neighbourhood Play Study; a national, cross-border research project which recorded children’s play patterns in Ireland during 2012. The study incorporated 1688 families across 240 communities. Data was established on the play choices of children aged from birth to 14 years. Multiple differentials were explored including socio-economic and geographical environments.
This paper focuses on the findings within imaginary play patterns for the full cohort. As such, it presents the play patterns for imaginary play in children aged birth-14 years. The findings are discussed in the context of developmental patterns with particular emphasis on the relationship between imaginary play and the development of creativity.
Creativity is a key concept within contemporary education. Its central nexus is problem solving in the face of uncertainty. Within a rapidly changing world, it is a key skill requirement for today’s children as they grow towards efficacy within instability. The relationship between the development of creativity and children’s engagement with imaginary play practices are explored in this paper.
©IATED (2017). Reproduced in Research Online with permission
A finite difference soil-structure interaction study of a section of the Bonneville Navigation Lock buttress diaphragm wall utilizing pressuremeter test results
The P-y curve, used in current practice as an efficient Iine-load vs. soi displacement model for input into the finite difference method of laterally loaded pile analysis, is extended in this study for use with cohesionless soils in diaphragm wall analysis on the Personal Computer with the BMCOL7 program. An analogous W-y curve is proposed, an elastic-plastic model with line-load limits developed from classical earth-pressure theories.
A new formula for predicting a horizontal walI modulus for cohesionless soiIs from the pressuremeter modulus is developed for use in predicting the displacements on the W-y curves. The resulting modulus values are shown to yield reasonable displacements values.
A new procedure for modeling preloaded tie-back anchors and staged excavation for diaphragm walIs was developed, utiIizing multiple computer runs, updated the W-y curves, and superposition of deflections.
These new developments were applied to a parametric study of a deflection-critical section of the new Bonnevilie Nav-Lock Buttress Diaphragm Wall, for which extensive high-quality pressuremeter test results were available. Deflection curves of the wall are presented, showing the effect of variations in anchor preload, walI cracking, anchor slip, at-rest pressure, and soiI modulus.
The results indicate that preloading will reduce wall deflections by at least 4-fold, but that wall cracking can potentially double deflections. Safety factors against passive soil failure were determined to be about 5 at anchor preload, and more than 40 after fulI excavation
The influences of opportunity. Differences in children\u27s play choices across diverse communities in Ireland
This paper presents findings from The Irish Neighbourhood Play Project; a research study initiated by IT Sligo and Early Childhood Ireland in 2012. The focus of this paper is on the data section which highlights children’s play choices and opportunities across socio-economic communities. The study incorporated almost 1800 families across 240 communities. Data was collected within disadvantaged communities, middle class communities and affluent communities. Where and what children are playing was investigated. The choices children and families make within play have a direct effect on the developing brain of the young child (Acar & Torquati, 2015). This, in turn, affects school performance and engagement. Choices however, are often framed by opportunities; opportunities are framed by government policy and investment in community facilities as well as socio-cultural norms. The data from this project shows that children across socio-economic divides are engaging in dramatically different play, experiences and activities. Key differences also emerged in relation to how children in diverse communities are engaging with technology. The differences across multiple themes are startling and offer insights into the breadth of childhood experience across the Island of Ireland.
©IATED (2017). Reproduced in Research Online with permission
Let\u27s get real: are today\u27s children playing with nature? Do the educational aspirations of the nature play movement emerge within children\u27s neighbourhood play?
The Irish Neighbourhood Play Research Project was a large scale research project which included almost 1700 participant families and 240 communities throughout Ireland. It used parental surveys and naturalistic observation to secure data on how children in modern Ireland aged 0-15 are spending their free time. An all-island approach was taken incorporating cities, towns and rural areas across a variety of socio-economic groupings.
Interesting findings arose from the data relating to the choices that children are making within their free time. This paper focuses on the choices they are making within their engagement with nature and natural materials. Data on the children’s nature choices will be presented and discussed through a child development lens. The positive and negative implications for both learning and development are raised. This leads us to interesting questions about the role of nature within child development and learning. As an international nature play movement gains ground in raising awareness about the importance of nature based learning and its linkages with educational structure and pedagogy, this research into children’s nature choices is timely
©IATED (2016). Reproduced in Research Online with permission
Children\u27s choices: the technology choices that children make within their free time. Influences and implications
The Irish Neighbourhood Play Research Project included almost 1700 families and 240 communities throughout Ireland. Using parental surveys and naturalistic observation, data was secured on how children in modern Ireland aged 0-14 are spending their free time. An all-island approach was taken incorporating cities, towns and rural areas across a variety of socio-economic groupings. Interesting findings arose from the data relating to the choices that children are making within their free time. This paper focuses on the choices they are making within technology use. Data on the children’s technological engagement will be presented and discussed through a child development lens. The positive and negative implications for both learning and development are raised. This generation of children will be the first to emerge into adulthood without ever experiencing a world without technology. For them, it will always have been central to their existence. What does this mean for the next generation of humanity?
©IATED (2016). Permission granted by IATED for inclusion in ResearchOnline@N
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