8,388 research outputs found
Balinese Family: Keluarga
In Balinese, this word means “family.” In Banjar Wani this word means “everyone,” because everyone feels like family. [excerpt
Study of metallic structural design concepts for an arrow wing supersonic cruise configuration
A structural design study was made, to assess the relative merits of various metallic structural concepts and materials for an advanced supersonic aircraft cruising at Mach 2.7. Preliminary studies were made to ensure compliance of the configuration with general design criteria, integrate the propulsion system with the airframe, select structural concepts and materials, and define an efficient structural arrangement. An advanced computerized structural design system was used, in conjunction with a relatively large, complex finite element model, for detailed analysis and sizing of structural members to satisfy strength and flutter criteria. A baseline aircraft design was developed for assessment of current technology. Criteria, analysis methods, and results are presented. The effect on design methods of using the computerized structural design system was appraised, and recommendations are presented concerning further development of design tools, development of materials and structural concepts, and research on basic technology
Study of advanced composite structural design concepts for an arrow wing supersonic cruise configuration
Based on estimated graphite and boron fiber properties, allowable stresses and strains were established for advanced composite materials. Stiffened panel and conventional sandwich panel concepts were designed and analyzed, using graphite/polyimide and boron/polyimide materials. The conventional sandwich panel was elected as the structural concept for the modified wing structure. Upper and lower surface panels of the arrow wing structure were then redesigned, using high strength graphite/polyimide sandwich panels, retaining the titanium spars and ribs from the prior study. The ATLAS integrated analysis and design system was used for stress analysis and automated resizing of surface panels. Flutter analysis of the hybrid structure showed a significant decrease in flutter speed relative to the titanium wing design. The flutter speed was increased to that of the titanium design by selective increase in laminate thickness and by using graphite fibers with properties intermediate between high strength and high modulus values
Spontaneous and Stimulated Raman Scattering near Metal Nanostructures in the Ultrafast, High-Intensity regime
The inclusion of atomic inversion in Raman scattering can significantly alter
field dynamics in plasmonic settings. Our calculations show that large local
fields and femtosecond pulses combine to yield: (i) population inversion within
hot spots; (ii) gain saturation; and (iii) conversion efficiencies
characterized by a switch-like transition to the stimulated regime that spans
twelve orders of magnitude. While in Raman scattering atomic inversion is
usually neglected, we demonstrate that in some circumstances full accounting of
the dynamics of the Bloch vector is required
Strain controlled oxygen vacancy formation and ordering in CaMnO
We use first-principles calculations to investigate the stability of
bi-axially strained \textit{Pnma} perovskite CaMnO towards the formation of
oxygen vacancies. Our motivation is provided by promising indications that
novel material properties can be engineered by application of strain through
coherent heteroepitaxy in thin films. While it is usually assumed that such
epitaxial strain is accommodated primarily by changes in intrinsic lattice
constants, point defect formation is also a likely strain relaxation mechanism.
This is particularly true at the large strain magnitudes (4%) which
first-principles calculations often suggest are required to induce new
functionalities. We find a strong dependence of oxygen vacancy defect formation
energy on strain, with tensile strain lowering the formation energy consistent
with the increasing molar volume with increasing oxygen deficiency. In
addition, we find that strain differentiates the formation energy for different
lattice sites, suggesting its use as a route to engineering vacancy ordering in
epitaxial thin films.Comment: 7 pages, 7 figure
Fearful temperament moderates the association between positive parenting and children\u27s social competence during early childhood
Social competence during kindergarten has been linked to adaptive teacher-child and peer relationships. The quality of parents’ interaction with their children during the toddler years may promote better social development placing children on a trajectory towards social competence. Quite possibly, children vary in how responsive they are to parenting efforts. This study evaluated the extent to which positive parenting predicted change in social competence from child age 3 to 4 among 137 parent-child dyads. Observational measures of positive parenting and fearful temperament were analyzed when children were 3-years of age. Teacher reports of social competence in the classroom were collected during children’s 4-year old assessment. Positive parenting was positively associated with children’s level of social competence. No evidence emerged of fearful temperament as a moderator for the association between positive parenting and social competence. Regardless of children’s temperament, all children benefit from positive parenting during early childhood
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