84,913 research outputs found
Combustion: Structural interaction in a viscoelastic material
The effect of interaction between combustion processes and structural deformation of solid propellant was considered. The combustion analysis was performed on the basis of deformed crack geometry, which was determined from the structural analysis. On the other hand, input data for the structural analysis, such as pressure distribution along the crack boundary and ablation velocity of the crack, were determined from the combustion analysis. The interaction analysis was conducted by combining two computer codes, a combustion analysis code and a general purpose finite element structural analysis code
Theoretical and experimental investigation on modulation-inducing retrodirective optical systems /miros/ monthly progress report, 20 dec. 1964 - 20 jan. 1965
Modulation inducing retrodirecting optical system - diode mount for gallium arsenide lasers, and generation of alkaline line by stimulated Raman emissio
Origin of spin reorientation transitions in antiferromagnetic MnPt-based alloys
Antiferromagnetic MnPt exhibits a spin reorientation transition (SRT) as a
function of temperature, and off-stoichiometric Mn-Pt alloys also display SRTs
as a function of concentration. The magnetocrystalline anisotropy in these
alloys is studied using first-principles calculations based on the coherent
potential approximation and the disordered local moment method. The anisotropy
is fairly small and sensitive to the variations in composition and temperature
due to the cancellation of large contributions from different parts of the
Brillouin zone. Concentration and temperature-driven SRTs are found in
reasonable agreement with experimental data. Contributions from specific
band-structure features are identified and used to explain the origin of the
SRTs.Comment: 6 pages, 8 figure
Mental Health And The Role Of The States
Researchers from the State Health Care Spending Project -- a collaboration between The Pew Charitable Trusts and the John D. and Catherine T. MacArthur Foundation -- sought to better understand the country's mental health challenges and, in particular, the states' role in addressing them. The project found that:In 2013, approximately 44 million adults -- 18.5 percent of the population 18 and older -- were classified as having a mental illness. Of these, 10 million had a serious mental illness. The rate of serious mental illness varied from state to state.In 2009, the most recent year for which national mental health data are available, 22 billion (15 percent) in 2009. This total does not include state and local Medicaid expenditures. Counting those contributions brings total state and local spending up to $35.5 billion (24 percent).This report is intended to help federal, state, and local policymakers working to address the country's mental health challenges to better understand their prevalence, treatment, and funding trends
A secondary ejecta explanation of a lunar seismogram
Secondary ejecta explanation to seismograph of Apollo 12 LM impac
Development of a variational SEASAT data analysis technique
Oceans are data-sparse areas in terms of conventional weather observations. The surface pressure field obtained solely by analyzing the conventional weather data is not expected to possess high accuracy. On the other hand, in entering asynoptic data such as satellite-derived temperature soundings into an atmospheric prediction system, an improved surface analysis is crucial for obtaining more accurate weather predictions because the mass distribution of the entire atmosphere will be better represented in the system as a result of the more accurate surface pressure field. In order to obtain improved surface pressure analyses over the oceans, a variational adjustment technique was developed to help blend the densely distributed surface wind data derived from the SEASAT-A radar observations into the sparsely distributed conventional pressure data. A simple marine boundary layer scheme employed in the adjustment technique was discussed. In addition, a few aspects of the current technique were determined by numerical experiments
Two-terminal monolithic InP-based tandem solar cells with tunneling intercell ohmic connections
A monolithic two-terminal InP/InGaAsP tandem solar cell was successfully fabricated. This tandem solar cell consists of a p/n InP homojunction top subcell and a 0.95 eV p/n InGaAsP homojunction bottom subcell. A patterned 0.95 eV n(+)/p(+) InGaAsP tunnel diode was employed as an intercell ohmic connection. The solar cell structure was prepared by two-step liquid phase epitaxial growth. Under one sun, AM1.5 global illumination, the best tandem cell delivered a conversion efficiency of 14.8 pct
The weakly perturbed Schwarzschild lens in the strong deflection limit
We investigate the strong deflection limit of gravitational lensing by a
Schwarzschild black hole embedded in an external gravitational field. The study
of this model, analogous to the Chang & Refsdal lens in the weak deflection
limit, is important to evaluate the gravitational perturbations on the
relativistic images that appear in proximity of supermassive black holes hosted
in galactic centers. By a simple dimensional argument, we prove that the tidal
effect on the light ray propagation mainly occurs in the weak field region far
away from the black hole and that the external perturbation can be treated as a
weak field quadrupole term. We provide a description of relativistic critical
curves and caustics and discuss the inversion of the lens mapping. Relativistic
caustics are shifted and acquire a finite diamond shape. Sources inside the
caustics produce four sequences of relativistic images. On the other hand,
retro-lensing caustics are only shifted while remaining point-like to the
lowest order.Comment: 12 pages, 1 figure
Reptile scale paradigm: Evo-Devo, pattern formation and regeneration
The purpose of this perspective is to highlight the merit of the reptile integument as an experimental model. Reptiles represent the first amniotes. From stem reptiles, extant reptiles, birds and mammals have evolved. Mammal hairs and feathers evolved from Therapsid and Sauropsid reptiles, respectively. The early reptilian integument had to adapt to the challenges of terrestrial life, developing a multi-layered stratum corneum capable of barrier function and ultraviolet protection. For better mechanical protection, diverse reptilian scale types have evolved. The evolution of endothermy has driven the convergent evolution of hair and feather follicles: both form multiple localized growth units with stem cells and transient amplifying cells protected in the proximal follicle. This topological arrangement allows them to elongate, molt and regenerate without structural constraints. Another unique feature of reptile skin is the exquisite arrangement of scales and pigment patterns, making them testable models for mechanisms of pattern formation. Since they face the constant threat of damage on land, different strategies were developed to accommodate skin homeostasis and regeneration. Temporally, they can be under continuous renewal or sloughing cycles. Spatially, they can be diffuse or form discrete localized growth units (follicles). To understand how gene regulatory networks evolved to produce increasingly complex ectodermal organs, we have to study how prototypic scale-forming pathways in reptiles are modulated to produce appendage novelties. Despite the fact that there are numerous studies of reptile scales, molecular analyses have lagged behind. Here, we underscore how further development of this novel experimental model will be valuable in filling the gaps of our understanding of the Evo-Devo of amniote integuments
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