Controlled Ecological Life Support Systems (CELSS) conceptual design option study

Results are given of a study to explore options for the development of a Controlled Ecological Life Support System (CELSS) for a future Space Station. In addition, study results will benefit the design of other facilities such as the Life Sciences Research Facility, a ground-based CELSS demonstrator, and will be useful in planning longer range missions such as a lunar base or manned Mars mission. The objectives were to develop weight and cost estimates for one CELSS module selected from a set of preliminary plant growth unit (PGU) design options. Eleven Space Station CELSS module conceptual PGU designs were reviewed, components and subsystems identified and a sensitivity analysis performed. Areas where insufficient data is available were identified and divided into the categories of biological research, engineering research, and technology development. Topics which receive significant attention are lighting systems for the PGU, the use of automation within the CELSS system, and electric power requirements. Other areas examined include plant harvesting and processing, crop mix analysis, air circulation and atmosphere contaminant flow subsystems, thermal control considerations, utility routing including accessibility and maintenance, and nutrient subsystem design

The development of one teacher\u27s skills at instructional conversation

This study examined one teacher\u27s learning and implementing instructional conversations (Tharp and Gallimore, 1988). She received assistance through opportunities to: 1) observe effective examples of instructional conversations; 2) practice skills and get immediate feedback through conversation; 3) read and discuss articles about instructional conversations and questioning techniques; and 4) read and comment on transcripts of lessons and follow-up conversations. Participant-observation, unstructured conversations, and interviews comprised the data, which included transcripts of audio-taped lessons, follow-up conversations, and interviews. There was a gradual shift in the teacher\u27s practices from recitation to instructional conversation. Action, reflection, and collaborative talk became the process of change in her practice and thinking. Additionally, data revealed that students gave longer responses, initiated conversation, and participated in responsive conversation in which they contributed to, challenged, and extended each others\u27 statements. implications for teachers\u27 professional development are discussed

Assessment of the Mars Science Laboratory Entry, Descent, and Landing Simulation

On August 5, 2012, the Mars Science Laboratory rover, Curiosity, successfully landed inside Gale Crater. This landing was only the seventh successful landing and fourth rover to be delivered to Mars. Weighing nearly one metric ton, Curiosity is the largest and most complex rover ever sent to investigate another planet. Safely landing such a large payload required an innovative Entry, Descent, and Landing system, which included the first guided entry at Mars, the largest supersonic parachute ever flown at Mars, and a novel and untested Sky Crane landing system. A complete, end-to-end, six degree-of-freedom, multi-body computer simulation of the Mars Science Laboratory Entry, Descent, and Landing sequence was developed at the NASA Langley Research Center. In-flight data gathered during the successful landing is compared to pre-flight statistical distributions, predicted by the simulation. These comparisons provide insight into both the accuracy of the simulation and the overall performance of the vehicle

Modeling and analysis methodology for aeroelastically tailored chordwise deformable wings

Structural concepts have been created which produce chordwise camber deformation that results in enhanced lift. A wing box can be tailored to utilize each of these with composites. In attempting to optimize the aerodynamic benefits, we have found there are two optimal designs that are of interest. There is a weight optimum which corresponds to the maximum lift per unit structural weight. There is also a lift optimum that corresponds to maximum absolute lift. New structural models, the basic deformation mechanisms that are utilized and typical analytical results are presented. It appears that lift enhancements of sufficient magnitude can be produced to render this type of wing tailoring of practical interest. Experiments and finite element correlations are performed which confirm the validity of the theoretical models utilized

Internal wave effects on acoustic propagation

Underwater Acoustics Measurements (UAM) 1st International Conference “Underwater Acoustic Measurements: Technologies & Results,” 28 June- 1 July 2005, Heraklion, Crete, Greece,Internal gravity wave induced acoustic fluctuations are reviewed. It is well known that internal waves cause temporal and spatial variability above and beyond that caused by mesoscale and larger ocean heterogeneity. Increasingly detailed work over many decades has shown that deep-ocean internal waves, which have often been parameterized using the Garrett-Munk spectrum as a guide, are responsible for rapid acoustic field variability at all propagation ranges. Numerous experiments have shown that various sections of wavefronts from impulsive sources have fluctuation qualities well-described by theory, simulation, or both. In contrast, fluctuations in shallow water experiments, although known to be consistent with those expected from internal waves via theoretical and simulation arguments, are incompletely described by theories for a number of reasons. These reasons include nonstationary, inhomogeneous or anisotropic wave environments, unknown geoacoustic properties, and rapidly changing background currents, all of which prevent detailed comparison of observation and prediction. At this time, many different shallow-water internal wave scenarios give rise to similar field fluctuations, within reasonable confidence intervals for the predictions. This may simplify order-of magnitude fluctuation prediction, while simultaneously making inversion and highly-detailed prediction problematic.This work was supported by the Office of Naval Research

Assessment of left ventricle dynamic from cardiac magnetic resonance imaging by means a correspondence approach

In this research, an approach to assess the heart dynamics is reported. The cardiac magnetic resonance images are considered for assessing the left ventricle motion and deformation. The shape of the cavity is obtained by means a segmentation procedure based on a clustering algorithm at an initial instant. This three-dimensional structure is used to establish a region of interest around the border of the structure. An optical flow method allows determining the displacement vector of this region and then defining the shapes of the cavity during the all cardiac cycle. The points of the left ventricle are followed using the displacement vectors in the cardiac cycle, obtaining thus, a dense motion field of the cavity. This approximate deformation field is refined with a correspondence method that working in the three-dimensional space. The mapping of the points that define the left ventricle in the cardiac cycle obtained with the correspondence procedure are then used for computing a set of clinical parameters that allows assessing the motion and deformation of this principal structure of the human heart. The torsion, radial and longitudinal contraction are quantified. The obtained results are promising for evaluating the heart dynamics