27,943 research outputs found
Subsolar-meridian mean annual distributions for Martian troposphere below 50 kilometers
Subsolar-meridian mean annual distributions for Martian troposphere below 50 k
High performance sapphire windows
High-quality, wide-aperture optical access is usually required for the advanced laser diagnostics that can now make a wide variety of non-intrusive measurements of combustion processes. Specially processed and mounted sapphire windows are proposed to provide this optical access to extreme environment. Through surface treatments and proper thermal stress design, single crystal sapphire can be a mechanically equivalent replacement for high strength steel. A prototype sapphire window and mounting system have been developed in a successful NASA SBIR Phase 1 project. A large and reliable increase in sapphire design strength (as much as 10x) has been achieved, and the initial specifications necessary for these gains have been defined. Failure testing of small windows has conclusively demonstrated the increased sapphire strength, indicating that a nearly flawless surface polish is the primary cause of strengthening, while an unusual mounting arrangement also significantly contributes to a larger effective strength. Phase 2 work will complete specification and demonstration of these windows, and will fabricate a set for use at NASA. The enhanced capabilities of these high performance sapphire windows will lead to many diagnostic capabilities not previously possible, as well as new applications for sapphire
A technique for solving certain Wiener-Hopf type boundary value problems Technical report no. 9
Technique for solving Weiner-Hopf type boundary value problem
An alternative approach to the solution of a class of Wiener-Hopf and related problems Technical report no. 8
Alternative method to Weiner-Hopf approach for solving radiation and diffraction problem
Alternative Support for Teachers In Challenging Economic Times: The Use of Virtual Coaching
This qualitative study explored the use of virtual literacy coaching by examining 18 coaching sessions between a university-based literacy coach and a first-grade reading interventionist using Adobe Connect, a web-based collaborative tool. The application provided a virtual meeting space and through the use of video pods the teacher and coach had synchronous audio and video communication. Each coaching session lasted approximately one hour and included a pre-observation discussion, a 30-minute individualized lesson with a struggling reader, and a debriefing conversation. Data, including transcriptions of the coaching sessions, interviews with participants, field notes, and journal entries were analyzed using the constant-comparative method. Categories that reflected patterns in the data were collapsed into themes, which highlighted the influence of the virtual environment on the relationship between coach and teacher and their coaching interactions
Reading Recovery in South Carolina: 2018-2019 State Report
Developed by New Zealand educator Dr. Marie M. Clay, Reading Recovery® is a short-term early intervention for first grade students who have the lowest achievement on measures of literacy outcomes. Students meet individually with a specially trained teacher for 30 minutes each day for a period of 12-20 weeks. The goal during this period is for children to develop a network of reading and writing strategies so they may independently perform within the average range of their class
Cosmological production of H_2 before the formation of the first galaxies
Previous calculations of the pregalactic chemistry have found that a small
amount of H_2, x[H_2]=n[H_2]/n[H] = 2.6e-6, is produced catalytically through
the H^-, H_2^+, and HeH^+ mechanisms. We revisit this standard calculation
taking into account the effects of the nonthermal radiation background produced
by cosmic hydrogen recombination, which is particularly effective at destroying
H^- via photodetachment. We also take into consideration the non-equilibrium
level populations of H_2^+, which occur since transitions among the
rotational-vibrational levels are slow compared to photodissociation. The new
calculation predicts a final H_2 abundance of x[H_2] = 6e-7 for the standard
cosmology. This production is due almost entirely to the H^- mechanism, with ~1
per cent coming from HeH^+ and ~0.004 per cent from H_2^+. We evaluate the
heating of the diffuse pregalactic gas from the chemical reactions that produce
H_2 and from rotational transitions in H_2, and find them to be negligible.Comment: 13 pages, 5 figures, MNRAS submitte
Strengths of sulfur-basalt concretes
Sulfur used in bonding high strength basalt aggregates to form sulfur-basalt concrete
Elephant cognition in primate perspective
On many of the staple measures of comparative psychology, elephants show no obvious differences from other mammals, such as primates: discrimination learning, memory, spontaneous tool use, etc. However, a range of more naturalistic measures have recently suggested that elephant cognition may be rather different. Wild elephants sub-categorize humans into groups, independently making this classification on the basis of scent or colour. In number discrimination, elephants show no effects of absolute magnitude or relative size disparity in making number judgements. In the social realm, elephants show empathy into the problems faced by others, and give hints of special abilities in cooperation, vocal imitation and perhaps teaching. Field data suggest that the elephant’s vaunted reputation for memory may have a factual basis, in two ways. Elephants’ ability to remember large-scale space over long periods suggests good cognitive mapping skills. Elephants’ skill in keeping track of the current locations of many family members implies that working memory may be unusually developed, consistent with the laboratory finding that their quantity judgements do not show the usual magnitude effects.Publisher PDFPeer reviewe
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