Structures and Materials Working Group report

The appropriateness of the selection of four issues (advanced materials development, analysis/design methods, tests of large flexible structures, and structural concepts) was evaluated. A cross-check of the issues and their relationship to the technology drivers is presented. Although all of the issues addressed numerous drivers, the advanced materials development issue impacts six out of the seven drivers and is considered to be the most crucial. The advanced materials technology development and the advanced design/analysis methods development were determined to be enabling technologies with the testing issues and development of structural concepts considered to be of great importance, although not enabling technologies. In addition, and of more general interest and criticality, the need for a Government/Industry commitment which does not now exist, was established. This commitment would call for the establishment of the required infrastructure to facilitate the development of the capabilities highlighted through the availability of resources and testbed facilities, including a national testbed in space to be in place in ten years

Closed-form solutions for linear regulator design of mechanical systems including optimal weighting matrix selection

Vibration in modern structural and mechanical systems can be reduced in amplitude by increasing stiffness, redistributing stiffness and mass, and/or adding damping if design techniques are available to do so. Linear Quadratic Regulator (LQR) theory in modern multivariable control design, attacks the general dissipative elastic system design problem in a global formulation. The optimal design, however, allows electronic connections and phase relations which are not physically practical or possible in passive structural-mechanical devices. The restriction of LQR solutions (to the Algebraic Riccati Equation) to design spaces which can be implemented as passive structural members and/or dampers is addressed. A general closed-form solution to the optimal free-decay control problem is presented which is tailored for structural-mechanical system. The solution includes, as subsets, special cases such as the Rayleigh Dissipation Function and total energy. Weighting matrix selection is a constrained choice among several parameters to obtain desired physical relationships. The closed-form solution is also applicable to active control design for systems where perfect, collocated actuator-sensor pairs exist

Fabrication of J79 boron/aluminum compressor blades

A total of 81 boron/aluminum first stage compressor blades were developed. The processing of the blades and the series designs established for various types of blade tests are described

NASA'S controls-structures interaction program

A NASA program is about to start which has the objective to advance Controls-Structures Interaction (CSI) technology to a point where it can be used in spacecraft design for future missions. Because of the close interrelationships between the structure, the control hardware, and the analysis/design, a highly interdisciplinary activity is defined in which structures, dynamics, controls, computer and electronics engineers work together on a daily basis and are co-located to a large extent. Methods will be developed which allow the controls and structures analysis and design functions to use the same mathematical models. Hardware tests and applications are emphasized and will require development of concepts and test methods to carry out. Because of a variety of mission application problem classes, several time-phased, focus ground test articles are planned. They will be located at the Langley Researdh Center (LaRC), the Marshall Space Flight Center (MSFC) and at the Jet Propulsion Laboratory (JPL). It is anticipated that the ground tests will be subject to gravity and other environmental effects to the extent that orbital flights tests will be needed for verification of some technology items. The need for orbital flight experiments will be quantified based on ground test results and mission needs. Candidate on-orbit experiments will be defined and preliminary design/definition and cost studies will be carried out for one or more high-priority experiments

Generation of Lamprey Monoclonal Antibodies (Lampribodies) Using the Phage Display System.

The variable lymphocyte receptors (VLRs) consist of leucine rich repeats (LRRs) and comprise the humoral antibodies produced by lampreys and hagfishes. The diversity of the molecules is generated by stepwise genomic rearrangements of LRR cassettes dispersed throughout the VLRB locus. Previously, target-specific monovalent VLRB antibodies were isolated from sea lamprey larvae after immunization with model antigens. Further, the cloned VLR cDNAs from activated lamprey leukocytes were transfected into human cell lines or yeast to select best binders. Here, we expand on the overall utility of the VLRB technology by introducing it into a filamentous phage display system. We first tested the efficacy of isolating phage into which known VLRB molecules were cloned after a series of dilutions. These experiments showed that targeted VLRB clones could easily be recovered even after extensive dilutions (1 to 109). We further utilized the system to isolate target-specific "lampribodies" from phage display libraries from immunized animals and observed an amplification of binders with relative high affinities by competitive binding. The lampribodies can be individually purified and ostensibly utilized for applications for which conventional monoclonal antibodies are employed

Regolith production and transport at the Susquehanna Shale Hills Critical Zone Observatory, Part 2: Insights from meteoric 10Be

Regolith-mantled hillslopes are ubiquitous features of most temperate landscapes, and their morphology reflects the climatically, biologically, and tectonically mediated interplay between regolith production and downslope transport. Despite intensive research, few studies have quantified both of these mass fluxes in the same field site. Here we present an analysis of 87 meteoric 10Be measurements from regolith and bedrock within the Susquehanna Shale Hills Critical Zone Observatory (SSHO), in central Pennsylvania. Meteoric 10Be concentrations in bulk regolith samples (n=73) decrease with regolith depth. Comparison of hillslope meteoric 10Be inventories with analyses of rock chip samples (n=14) from a 24 m bedrock core confirms that >80% of the total inventory is retained in the regolith. The systematic downslope increase of meteoric 10Be inventories observed at SSHO is consistent with 10Be accumulation in slowly creeping regolith (∼ 0.2 cm yr-1). Regolith flux inferred from meteoric 10Be varies linearly with topographic gradient (determined from high-resolution light detection and ranging-based topography) along the upper portions of hillslopes at SSHO. However, regolith flux appears to depend on the product of gradient and regolith depth where regolith is thick, near the base of hillslopes. Meteoric 10Be inventories at the north and south ridgetops indicate minimum regolith residence times of 10.5 ± 3.7 and 9.1 ± 2.9 ky, respectively, similar to residence times inferred from U-series isotopes in Ma et al. (2013). The combination of our results with U-series-derived regolith production rates implies that regolith production and erosion rates are similar to within a factor of two on SSHO hillcrests. ©2013. American Geophysical Union. All Rights Reserved

The western economy in the 80s

Federal Reserve District, 12th ; Economic conditions - West (U.S.)

Wrongful Birth: The Emerging Status of a New Tort.

Abstract Forthcoming

Status of the Mast experiment

Many sophisticated mathematical control techniques for flexible structures have been devised. The basic problem is that most of them require a relatively accurate mathematical model of the system under control including the dynamics of both the structure and the control system components. Obtaining such a model for either subsystem traditionally has required great effort including a significant validation step based on test data. Because of the quantum increase in complexity over proven methods, promising techniques for the control of flexible structures must be validated in actual hardware experiments before committing to their use in actual spacecraft missions. The Mast experiment system serves as a focus for such validation. It is the first in a series of experiments under the Control of Flexible Structures (COFS) Program at the NASA Langley Research Center. The Mast experiment is a combination of ground tests, orbital flight test, and analysis of a deployable beam under the COFS program. It provides a vehicle for research in structures, structural dynamics, and control issues

Amplification Dynamics of Platy-1 Retrotransposons in the Cebidae Platyrrhine Lineage

Platy-1 elements are Platyrrhine-specific, short interspersed elements originally discovered in the Callithrix jacchus (common marmoset) genome. To date, only the marmoset genome has been analyzed for Platy-1 repeat content. Here, we report full-length Platy-1 insertions in other New World monkey (NWM) genomes (Saimiri boliviensis, squirrel monkey; Cebus imitator, capuchin monkey; and Aotus nancymaae, owl monkey) and analyze the amplification dynamics of lineage-specific Platy-1 insertions. A relatively small number of full-length and lineage-specific Platy-1 elements were found in the squirrel, capuchin, and owl monkey genomes compared with the marmoset genome. In addition, only a few older Platy-1 subfamilies were recovered in this study, with no Platy-1 subfamilies younger than Platy-1-6. By contrast, 62 Platy-1 subfamilies were discovered in the marmoset genome. All of the lineage-specific insertions found in the squirrel and capuchin monkeys were fixed present. However, similar to 15% of the lineage-specific Platy-1 loci in Aotus were polymorphic for insertion presence/absence. In addition, two new Platy-1 subfamilies were identified in the owl monkey genome with low nucleotide divergences compared with their respective consensus sequences, suggesting minimal ongoing retrotransposition in the Aotus genus and no current activity in the Saimiri, Cebus, and Sapajus genera. These comparative analyses highlight the finding that the high number of Platy-1 elements discovered in the marmoset genome is an exception among NWM analyzed thus far, rather than the rule. Future studies are needed to expand upon our knowledge of Platy-1 amplification in other NWM genomes