2,607 research outputs found
New Models in Cell-Wall Mechanics
A comparison is made of the mechanical behavior of fiber cell-wall models with complete shear restraint and the earlier model of Mark in which shear restraint was assumed in the case of the S1 layer only. Literature review and experimental work indicate that for different circumstances, different models may be more appropriate. A further modification of the general analytical approach is offeredâa "two-wall" analysis that allows for the general existence of different transverse strains in radial and tangential walls, respectively. A more refined calculation of the elastic constants of each cell-wall layer is also employed. The effect of certain cell-wall parameters on stress and strain distribution is explored. New experimental work on the torsional behavior of wood fibers is presented in the light of the theoretical models for cell walls
Operation of the computer model for microenvironment solar exposure
A computer model for microenvironmental solar exposure was developed to predict solar exposure to satellite surfaces which may shadow or reflect on one another. This document describes the technical features of the model as well as instructions for the installation and use of the program
Calculated values of atomic oxygen fluences and solar exposure on selected surfaces of LDEF
Atomic oxygen (AO) fluences and solar exposure have been modeled for selected hardware from the Long Duration Exposure Facility (LDEF). The atomic oxygen exposure was modeled using the microenvironment modeling code SHADOWV2. The solar exposure was modeled using the microenvironment modeling code SOLSHAD version 1.0
Operation of the computer model for direct atomic oxygen exposure of Earth satellites
One of the primary causes of material degradation in low Earth orbit (LEO) is exposure to atomic oxygen. When atomic oxygen molecules collide with an orbiting spacecraft, the relative velocity is 7 to 8 km/sec and the collision energy is 4 to 5 eV per atom. Under these conditions, atomic oxygen may initiate a number of chemical and physical reactions with exposed materials. These reactions contribute to material degradation, surface erosion, and contamination. Interpretation of these effects on materials and the design of space hardware to withstand on-orbit conditions requires quantitative knowledge of the atomic oxygen exposure environment. Atomic oxygen flux is a function of orbit altitude, the orientation of the orbit plan to the Sun, solar and geomagnetic activity, and the angle between exposed surfaces and the spacecraft heading. We have developed a computer model to predict the atomic oxygen exposure of spacecraft in low Earth orbit. The application of this computer model is discussed
Rotation-induced 3D vorticity in 4He superfluid films adsorbed on a porous glass
Detailed study of torsional oscillator experiments under steady rotation up
to 6.28 rad/sec is reported for a 4He superfluid monolayer film formed in 1
micrometer-pore diameter porous glass. We found a new dissipation peak with the
height being in proportion to the rotation speed, which is located to the lower
temperature than the vortex pair unbinding peak observed in the static state.
We propose that 3D coreless vortices ("pore vortices") appear under rotation to
explain this new peak. That is, the new peak originates from dissipation close
to the pore vortex lines, where large superfluid velocity shifts the vortex
pair unbinding dissipation to lower temperature. This explanation is confirmed
by observation of nonlinear effects at high oscillation amplitudes.Comment: 4pages, 5figure
Woe from stones: commemoration, identity politics and Estonia's 'War of Monuments'
No abstract available
A kapwa-infused paradigm in teaching Catholic theology/catechesis in a multireligious classroom in the Philippines
The increasing religious diversity in educational space has raised a legitimate question on how Catholic theology/ catechesis must be taught in Philippine Catholic universities given the institutional mandate to educate students âinto the faith of the Church through teaching of Christian doctrine in an organic and systematic wayâ (Wuerl, 2013, 1). On this note, the paper makes reference to âcentered plural- ismâ (CP), a positional posture espoused by Georgetown University in dealing with this predicament. In an attempt to (re) appropriate CP into local context, there is a need to explore the Filipino conception of self/others as enveloped within the indigenous concept of kapwa. Hereon, the paper finds that CP is not just feasibly suitable in local context but with kapwa's more inclusive description of the relationship of self and others, a CPâbased teaching paradigm in theology/ catechesis is a promising project in the educational scene of the Philippines
Finding the coast: environmental governance and the characterisation of land and sea
This is the author accepted manuscript. The final version is available from Wiley via the DOI in this record.In environmental governance for land and sea, the cultural is increasingly imbricated with the natural in the language of ecosystem services and the promise of integrated management. We are witnessing accelerated efforts to bring cultural and natural landscape character assessments into dialogue with other sorts of planning and governance mechanisms for coastal and marine environments. As land, sea, nature and culture are brought into closer correspondence, the coast assumes ever greater significance as a site and object of decisionâmaking in planning and environmental governance. In this paper, I draw on the critical analytical techniques of cultural geography to argue that coasts suffer from definitional ambiguity and conceptual insufficiency, both of which are exemplified by landscape and seascape characterisation, with specific consequences for environmental governance. I argue that we need to (1) both recognise and destabilise the unhelpful dichotomy between land and sea embodied in landscape and seascape character assessments, which have their provenance in landscape architecture; and (2) engage new language and conceptual tools that help us to rethink coasts critically. To this end, later on this paper, I briefly discuss alternative ways of conceptualising the coast, for example as a liminal space
One-pot homologation of boronic acids : a platform for diversity-oriented synthesis
Formal homologation of sp2-hybridized boronic acids is achieved via cross-coupling of boronic acids with conjunctive haloaryl BMIDA components in the presence of a suitably balanced basic phase. The utility of this approach to provide a platform for diversity-oriented synthesis in discovery medicinal chemistry is demonstrated in the context of the synthesis of a series of analogues of a BET bromodomain inhibitor
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