Engineering Papers⌕ Search

SEARCH · Engineering Papers

Results for “diversion”

Search indexed NASA NTRS and DOE OSTI research on propulsion, heat transfer, battery materials and energy systems. Follow report and document links to the original sources.

Quote a phrase for an exact phrase match. Source license links do not imply unrestricted reuse.

At least 343 records · Page 19
All sourcesNASA NTRSDOE OSTI
NASA NTRS1997

Reduced naphthylphthalamic acid binding in the tir3 mutant of Arabidopsis is associated with a reduction in polar auxin transport and diverse morphological defects

Polar auxin transport plays a key role in the regulation of plant growth and development. To identify genes involved in this process, we have developed a genetic procedure to screen for mutants of Arabidopsis that are altered in their response to auxin transport inhibitors. We recovered a total of 16 independent mutants that defined seven genes, called TRANSPORT INHIBITOR RESPONSE (TIR) genes. Recessive mutations in one of these genes, TIR3, result in altered responses to transport inhibitors, a reduction in polar auxin transport, and a variety of morphological defects that can be ascribed to changes in indole-3-acetic acid distribution. Most dramatically, tir3 seedlings are strongly deficient in lateral root production, a process that is known to depend on polar auxin transport from the shoot into the root. In addition, tir3 plants display a reduction in apical dominance as well as decreased elongation of siliques, pedicels, roots, and the inflorescence. Biochemical studies indicate that tir3 plants have a reduced number of N-1-naphthylphthalamic (NPA) binding sites, suggesting that the TIR3 gene is required for expression, localization, or stabilization of the NPA binding protein (NBP). Alternatively, the TIR3 gene may encode the NBP. Because the tir3 mutants have a substantial defect in NPA binding, their phenotype provides genetic evidence for a role for the NBP in plant growth and development.

Non-NASA Center↗
NASA NTRS1996

Diversity of eukaryotic microorganisms: computer-based resources, "The Handbook of Protoctista" and its "Glossary"

The kingdom Protoctista comprises some 30 phyla, including the eukaryotic anaerobes that permanently lack mitochondria, the Phylum Archaeprotista, with its three classes: (i) Archamoebae, e.g., Pelomyxa, Mastigina, (ii) Metamonada, e.g., Giardia, Pyrsonympha, and (iii) Parabasalia, e.g., Trichomonas, Calonympha, and the Phylum Microspora (Microsporidia), e.g., Vairimorpha. These and all algae, protozoa, labyrinthulids, "water molds" (oomycota, plasmodiophorans, hyphochytrids, chytrids, etc.) and other eukaryotes excluded from plants, animals and fungi are detailed in the Handbook of Protoctista. The Illustrated Glossary of Protoctista contains descriptions of the morphology and taxonomy of these microorganisms, including the many equivalent and homologous structures with different names. The Glossary has also been made into a Macintosh-compatible CD-ROM disk.

NASA Discipline Number 52-30↗
NASA NTRS1996

Kinetics of amino acid and glucose absorption following pancreatic diversion in the pig

An experiment was conducted in the pig to determine the consequences of deprivation of exocrine pancreatic secretion on the composition and quantity of nutrients absorbed after intake of a balanced diet. Five growing pigs (53.8 kg body weight) were fitted with permanent catheters in the portal vein and the carotid artery and with an electromagnetic flow probe around the portal vein to measure the exchanges between the blood and the intestinal lumen. They were also fitted with a permanent catheter in the duct of Wirsung to educe the exocrine pancreatic secretion and another one in the duodenum in order to reintroduce it. In each animal, glucose, amino-N and amino acid absorption as well as insulin and glucagon production were measured over a period of 10 h after the meal (semi-purified diet based on purified starch and containing 180 g fish meal/kg, DM content of the meal 731 g), either in the presence of pancreatic juice (group C: immediate reintroduction), or in the absence of pancreatic juice (group D: deprivation). The deprivation of pancreatic juice provoked a marked depression in the absorption of glucose (D 67.9 (SEM 27.9) g/10 h, C 437.7 (SEM 39.5) g/10 h, P < 0.001), and of amino-N (D 7.55 (SEM 0.54) g/10 h, C 15.80 (SEM 0.79) g/10 h, P < 0.001). The composition of the mixture of amino acids in the portal blood was only slightly modified: only the levels of histidine (P < 0.05) and of valine (P < 0.06, NS) decreased in the absence of pancreatic juice. Insulin production was much lower (by 64%, P < 0.05) in the absence of pancreatic juice whereas that of glucagon was not affected.

Glucose/metabolism↗
NASA NTRS1992

Evolution of EF-hand calcium-modulated proteins. II. Domains of several subfamilies have diverse evolutionary histories

In the first report in this series we described the relationships and evolution of 152 individual proteins of the EF-hand subfamilies. Here we add 66 additional proteins and define eight (CDC, TPNV, CLNB, LPS, DGK, 1F8, VIS, TCBP) new subfamilies and seven (CAL, SQUD, CDPK, EFH5, TPP, LAV, CRGP) new unique proteins, which we assume represent new subfamilies. The main focus of this study is the classification of individual EF-hand domains. Five subfamilies--calmodulin, troponin C, essential light chain, regulatory light chain, CDC31/caltractin--and three uniques--call, squidulin, and calcium-dependent protein kinase--are congruent in that all evolved from a common four-domain precursor. In contrast calpain and sarcoplasmic calcium-binding protein (SARC) each evolved from its own one-domain precursor. The remaining 19 subfamilies and uniques appear to have evolved by translocation and splicing of genes encoding the EF-hand domains that were precursors to the congruent eight and to calpain and to SARC. The rates of evolution of the EF-hand domains are slower following formation of the subfamilies and establishment of their functions. Subfamilies are not readily classified by patterns of calcium coordination, interdomain linker stability, and glycine and proline distribution. There are many homoplasies indicating that similar variants of the EF-hand evolved by independent pathways.

Non-NASA Center↗
NASA NTRS2000

Determining CDOM Absorption Spectra in Diverse Coastal Environments Using a Multiple Pathlength, Liquid Core Waveguide System. Measuring the Absorption of CDOM in the Field Using a Multiple Pathlength Liquid Waveguide System

We evaluated the accuracy, sensitivity and precision of a multiple pathlength, liquid core waveguide (MPLCW) system for measuring colored dissolved organic matter (CDOM) absorption in the UV-visible spectral range (370-700 nm). The MPLCW has four optical paths (2.0, 9.8, 49.3, and 204 cm) coupled to a single Teflon AF sample cell. Water samples were obtained from inland, coastal and ocean waters ranging in salinity from 0 to 36 PSU. Reference solutions for the MPLCW were made having a refractive index of the sample. CDOM absorption coefficients, a(sub CDOM), and the slope of the log-linearized absorption spectra, S, were compared with values obtained using a dual-beam spectrophotometer. Absorption of phenol red secondary standards measured by the MPLCW at 558 nm were highly correlated with spectrophotometer values (r > 0.99) and showed a linear response across all four pathlengths. Values of a(sub CDOM) measured using the MPLCW were virtually identical to spectrophotometer values over a wide range of concentrations. The dynamic range of a(sub CDOM) for MPLCW measurements was 0.002 - 231.5/m. At low CDOM concentrations (a(sub 370) < 0.1/m) spectrophotometric a(sub CDOM) were slightly greater than MPLCW values and showed larger fluctuations at longer wavelengths due to limitations in instrument precision. In contrast, MPLCW spectra followed an exponential to 600 nm for all samples. The maximum deviation in replicate MPLCW spectra was less than 0.001 absorbance units. The portability, sampling, and optical characteristics of a MPLCW system provide significant enhancements for routine CDOM absorption measurements in a broad range of natural waters.

Miller, Richard L.↗
NASA NTRS2005

Exploring Diverse Data Sets and Developing New Theories and Ideas With Project Integration Architecture

The development of new ideas is the essence of scientific research. This is frequently done by developing models of physical processes and comparing model predictions with results from experiments. With models becoming ever more complex and data acquisition systems becoming more powerful, the researcher is burdened with wading through data ranging in volume up to a level of many terabytes and beyond. These data often come from multiple, heterogeneous sources and usually the methods for searching through it are at or near the manual level. In addition, current documentation methods are generally limited to researchers pen-and-paper style notebooks. Researchers may want to form constraint-based queries on a body of existing knowledge that is, itself, distributed over many different machines and environments and from the results of such queries then spawn additional queries, simulations, and data analyses in order to discover new insights into the problem being investigated. Currently, researchers are restricted to working within the boundaries of tools that are inefficient at probing current and legacy data to extend the knowledge of the problem at hand and reveal innovative and efficient solutions. A framework called the Project Integration Architecture is discussed that can address these desired functionalities.

Benyo, Theresa L.↗
NASA NTRS2005

Studies of Coronae and Large Volcanoes on Venus: Constraining the Diverse Outcomes of Small-Scale Mantle Upwellings on Venus

Proxemy Research had a grant from NASA to perform science research on upwelling and volcanism on Venus. This was a 3 year Planetary Geology and Geophysics grant to E. Stofan, entitled Coronae and Large volcanoes on Venus. This grant closes on 12/31/05. Here we summarize the scientific progress and accomplishments of this grant. Scientific publications and abstracts of presentations are indicated in the final section. This was a very productive grant and the progress that was made is summarized. Attention is drawn to the publications and abstracts published in each year. The proposal consisted of two tasks, one examining coronae and one studying large volcanoes. The corona task (Task 1) consisted of three parts: 1) a statistical study of the updated corona population, with Sue Smrekar, Lori Glaze, Paula Martin and Steve Baloga; 2) geologic analysis of several specific groups of coronae, with Sue Smrekar and others; and 3) determining the histories and significance of a number of coronae with extreme amounts of volcanism, with Sue Smrekar. Task 2, studies of large volcanoes, consisted of two subtasks. In the first, we studied the geologic history of several volcanoes, with John Guest, Peter Grindrod, Antony Brian and Steve Anderson. In the second subtask, I analyzed a number of Venusian volcanoes with evidence of summit diking along with Peter Grindrod and Francis Nimmo.

Stofan, Ellen R.↗
NASA NTRS2005

Distribution and Diversity of Organic and Biological Signatures in Soils From the Atacama Desert

The Atacama Desert is amongst the driest places on Earth. It is considered to be a suitable analog for the Martian surface in which to conduct studies of life and life detection. Soil samples were collected in June 2005 from the Atacama Desert and analyzed in the lab for amino acid content. HPLC was the primary tool used to analyze samples. The amino acids of interest are aspartic acid, serine, glutamic acid, glycine, and alanine. D and L isomers of each amino acid (except for glycine) were separated through HPLC. The purpose of this study is to find correlations between location of the sample collection sites and amino acid content as well as D/L isomer ratios in order to formulate theories of how different types of environments may affect the abundance and distribution of life forms. Initial analysis of data shows a general lack of or slight correlation between location and amino acid content. Some data appears to contradict the hypothesis that harsher environments would have lower amino acid content than less harsh environments. Further analysis of data is needed to come up with a more conclusive report of the distribution of amino acids in the Atacama Desert.

Sharma, Aditi↗
NASA NTRS2001

Estimation of comprehensive forest variable sets from multiparameter SAR data over a large area with diverse species

Polarimetric and multifrequency data from the NASA/JPL airborne synthetic aperture radar (AIRSAR) have been used in a multi-tier estimation algorithm to calculate a comprehensive set of forest canopy properties including branch layer moisture and thickness, trunk density, trunk water content and diameter, trunk height, and subcanapy soil moisture. The estimation algorithm takes advantage of species-specific allometric relations, and is applied to a 100Km x 100Km area in the Canadian boreal region containing many different vegetation species types. The results show very good agreement with ground measurements taken at several focused and auxiliary study sites. This paper expands on the results reported in [1] and applies the algorithm on the regional scale.

variable estimation forestry multiparameter SAR↗
NASA NTRS2008

Plasma Processing of Lunar Regolith Simulant for Diverse Applications

Versatile manufacturing technologies for extracting resources from the moon are needed to support future space missions. Of particular interest is the production of gases and metals from lunar resources for life support, propulsion, and in-space fabrication. Deposits made from lunar regolith could yield highly emissive coatings and near-net shaped parts for replacement or repair of critical components. Equally important is development of high fidelity lunar simulants for ground based validation of potential lunar surface operations. Described herein is an innovative plasma processing technique for insitu production of gases, metals, coatings, and deposits from lunar regolith, and synthesis of high fidelity lunar simulant from NASA issued lunar simulant JSC-1. Initial plasma reduction trials of JSC-1 lunar simulant have indicated production of metallic iron and magnesium. Evolution of carbon monoxide has been detected subsequent to reduction of the simulant using the plasma process. Plasma processing of the simulant has also resulted in glassy phases resembling the volcanic glass and agglutinates found in lunar regolith. Complete and partial glassy phase deposits have been obtained by varying the plasma process variables. Experimental techniques, product characterization, and process gas analysis will be discussed.

Schofield, Elizabeth C.↗
NASA NTRS2006

Chemical Diversity along the Traverse of the Rover Spirit at Gusev Crater

The Alpha-Particle-X-ray Spectrometer (APXS) is part of the in situ payload of the Mars Exploration Rovers. It has determined the chemical composition of soils and rocks along the nearly 6 km long traverse of the rover Spirit. The measuring method a combination of PIXE and XRF using Cm244 sources - allowed the unambiguous identification of elemental compositions with high precision. Besides sample triage and quantification of saltforming elements as indicators for aqueous alteration, the APXS also delivered important constraints to mineralogy intruments (i.e., Mossbauer (MB), MiniTES, Pancam) on minerals and rock types. The mineralogy instruments on the other hand provided constraints on minerals used for APXS normative calculations and, e.g. allowed the attribution of S to sulfate, instead of sulfide or elemental sulfur. This abstract gives an updated overview of the data obtained up to our current rover position on sol 720 at the eastern base of the Columbia Hills. We will emphasize elemental correlations that imply the presence of certain minerals that can not be identified by the MER mineralogy instruments.

Gellert, R.↗